WO2022251597A1

WO2022251597A1 - Methods of treating neurological disorders with modulators of ribosomal protein s6 kinase alpha-1 (rsk1) and ribosomal protein s6 kinase alpha-3 (rsk2)

Info

Publication number: WO2022251597A1
Application number: PCT/US2022/031293
Authority: WO
Inventors: Thomas J.F. Nieland; Victor HANSON-SMITH; Irene Y. Choi
Original assignee: Verge Analytics, Inc.
Priority date: 2021-05-28
Filing date: 2022-05-27
Publication date: 2022-12-01
Also published as: TW202307005A

Abstract

The present disclosure relates to methods for treating a neurological disorder such as Parkinson's Disease (PD) and Alzheimer's Disease. The method may comprise administering to a subject in need thereof an effective amount of an agent that modulates RSK1 and/or RSK2.

Description

METHODS OF TREATING NEUROLOGICAL DISORDERS WITH MODULATORS OF RIBOSOMAL PROTEIN S6 KINASE ALPHA-1 (RSK1) AND RIBOSOMAL PROTEIN S6 KINASE ALPHA-3 (RSK2)

CROSS-REFERENCE TO RELATED APPLICATIONS [001] This application claims priority to U.S. Provisional Application No. 63/194,609, filed on May 28, 2021, the disclosures of which is hereby incorporated by reference in its entirety.

Technical Field

[002] The present disclosure provides methods for treating neurological disorders, in particular, neurodegenerative diseases. Compositions useful in the methods described herein include modulators of ribosomal protein S6 kinase alpha- 1 (RSK1) and ribosomal protein S6 kinase alpha-3 (RSK2).

Introduction and Summary

[003] The ribosomal S6 kinase (RSK) family of proteins regulate diverse cellular processes including cell growth, proliferation, survival, and motility. The RSK family includes four vertebrate isoforms, RSK1, RSK2, RSK3, and RSK4, and single family member orthologs are also present in Drosophila and C. elegans. The diversity of biological functions regulated by RSK proteins highlight the potential use of RSK proteins as therapeutic targets in human disease.

[004] Ribosomal protein S6 kinase alpha- 1 (RPS6KA1; RSK1) is a 90-kDA, serine/threonine kinase of the RSK family. RSK1 is highly expressed in human blood cells, which is consistent with its role in inflammatory processes (Figure IB). Within the brain, cell-type specific transcriptional profiling and single cell transcriptomic methods show RSK1 expression is highest in microglial cells (innate immune cells of the CNS) of healthy tissue, but also expressed in low levels in neurons (Figures 2 A and 2B).

[005] Phosphorylated RSK1 and ERK cytoplasmic aggregates have been reported in the substantia nigra Lewy bodies of Parkinson’s Disease (PD) patients (Zhu et ah, Am J Pathol 161(6):2087-2098 (2002)). RSK1 may phosphorylate microtubule associated protein (MAPT) (Virdee et ah, FEBS Lett 581(14):2657-62 (2007)), a cytoskeletal protein known to be aggregated in Alzheimer’s disease (AD). Also known as Tau, mutations in this gene are associated with frontotemporal dementia (Greaves et al., J Neurol 266(8):2075-2086 (2019)) and with PD (Davis et al., Neurobiol Aging (37:209.el-209.e7 (2016)).

[006] Ribosomal protein S6 kinase alpha-3 (RPS6KA3; RSK2) is a 90-kDA, serine/threonine kinase of the RSK family. RSK2 acts in the Ras/mitogen activated protein kinase (MAPK) signaling pathway. RSK2 is prominently expressed in brain structures essential for cognitive function and learning (Zeniou et al., Human Molecular Genetics ll(23):2929-2940 (2002)). Loss-of-function mutations in RSK2 have been implicated in Coffin-Lowry Syndrome (CLS), an X-linked mental retardation disorder associated with cognitive deficits and behavioral impairments (Lim et al., PLoS One 8(9):e74334 (2013)).

[007] The present disclosure is based in part on the findings that RSK1 and RSK2 are regulators of neurological pathways, such as PD- and ALS-specific signaling pathways. Accordingly, one aspect described herein provides a method of treating a neurological disorder, such as a neurodegenerative disease, the method comprising administering to a subject in need thereof an effective amount of an agent that modulates an RSK protein chosen from RSK1 and RSK2.

[008] The following embodiments are provided.

[009] Embodiment 1 is a method of treating a neurological disorder, the method comprising administering to a subject in need thereof an effective amount of an agent that modulates RSK1 and/or RSK2.

[0010] Embodiment 2 is the method of embodiment 1, wherein the neurological disorder is a neurological disorder in which the expression and/or activity levels of RSK1 and/or RSK2 detected in the subject is higher than a normal control.

[0011] Embodiment 3 is the method of embodiment 1 or 2 wherein the agent modulates RSK1.

[0012] Embodiment 4 is the method of embodiment 1 or 2 wherein the agent modulates RSK2.

[0013] Embodiment 5 is the method of any one of embodiments 1-4, wherein the agent that modulates RSK1 and/or RSK2 is a small molecule, an antibody, a peptide, a PROTAC, an antisense oligonucleotide, or an RNAi.

[0014] Embodiment 6 is the method of any one of embodiments 1-5, wherein the agent that modulates RSK1 and/or RSK2 is a small molecule.

[0015] Embodiment 7 is the method of any one of embodiments 1-3, 5, or 6, wherein modulation of RSK1 results in decreased expression of RSK1. [0016] Embodiment 8 is the method of embodiment 7, wherein the decreased expression level of RSK1 is at least 10%, at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, or more as compared to an appropriate control.

[0017] Embodiment 9 is the method of any one of embodiments 1-3, 5 or 6, wherein modulation of RSK1 results in decreased activity of RSK1.

[0018] Embodiment 10 is the method of embodiment 9, wherein the decreased activity of RSK1 is at least 10%, at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, or more as compared to an appropriate control.

[0019] Embodiment 11 is the method of any one of embodiments 1, 2, 4-6, wherein modulation of RSK2 results in decreased expression of RSK2.

[0020] Embodiment 12 is the method of embodiment 11, wherein the decreased expression level of RSK2 is at least 10%, at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, or more as compared to an appropriate control. [0021] Embodiment 13 is the method of any one of embodiments 1, 2, 4-6, wherein modulation of RSK2 results in decreased activity of RSK2.

[0022] Embodiment 14 is the method of embodiment 13, wherein the decreased activity of RSK2 is at least 10%, at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, or more as compared to an appropriate control.

[0023] Embodiment 15 is the method of any one of embodiments 1-14, wherein the neurological disorder is Parkinson’s Disease (PD), Parkinson’s Disease (PD) with Lewy bodies, amyotrophic lateral sclerosis (ALS), frontotemporal dementia (FTD), primary lateral sclerosis (PLS), Charcot-Marie-Tooth (CMT; including type 4J (CMT4J)), and Yunis-Varon syndrome, autophagy, polymicrogyria (including polymicrogyria with seizures), temporo-occipital polymicrogyria, Pick’s disease, dementia with Lewy bodies, Lewy body disease, diseases of neuronal nuclear inclusions of polyglutamine and intranuclear inclusion bodies, disease of Marinesco and Hirano bodies, tauopathy, Alzheimer’s disease, neurodegeneration, spongiform neurodegeneration, peripheral neuropathy, leukoencephalopathy, motor neuropathy, sensory neuropathy, abnormal lysosomal storage syndrome, myotubular myopathy, muscle weakness, cleidocranial dysplasia, Lewy body disease, inclusion body disease, progressive supranuclear palsy, corticobasal syndrome, chronic traumatic encephalopathy, traumatic brain injury (TBI), cerebral ischemia, Guillain-Barre Syndrome, chronic inflammatory demyelinating polyneuropathy, multiple sclerosis, a lysosomal storage disease, Fabry’s disorder, Gaucher’s disorder, Niemann Pick C disease, Tay-Sachs disease, and Mucolipidosis type IV, neuropathy, Coffin-Lowry Syndrome (CLS), X-linked mental retardation disorder (XLMR), intellectual disability, Huntington’s disease, a psychiatric disorder, ADHD, schizophrenia, a mood disorder, major depressive disorder, depression, bipolar disorder I, or bipolar disorder II.

[0024] Embodiment 16 is the method of any one of embodiments 1-14, wherein the neurological disorder is a neurodegenerative disease.

[0025] Embodiment 17 is the method of embodiment 16, wherein the neurodegenerative disease is amyotrophic lateral sclerosis (ALS), frontotemporal dementia (FTD), Alzheimer’s disease, Parkinson’s Disease (PD), Huntington’s disease, prion disease, Lewy body disease, Friedreich’s ataxia, or spinal muscular atrophy.

[0026] Embodiment 18 is the method of any one of embodiments 16 or 17, wherein the neurodegenerative disease is amyotrophic lateral sclerosis (ALS).

[0027] Embodiment 19 is the method of any one of embodiments 16 or 17, wherein the neurodegenerative disease is Parkinson’s Disease (PD).

[0028] Embodiment 20 is the method of embodiment 1-3, 5-10, or 15-19, wherein modulation of RSK1 modulates aggregation or toxicity of RSK1 and/or extracellular signal-regulated kinase (ERK).

[0029] Embodiment 21 is the method of embodiment 1-3, 5-10, or 15-19, wherein modulation of RSK1 modulates mammalian target of rapamycin (mTOR) signaling.

[0030] Embodiment 22 is the method of embodiment 1-3, 5-10, or 15-19, wherein modulation of RSK1 modulates phosphorylation to STAT1.

[0031] Embodiment 23 is the method of any one of embodiments 1-3, 5-10, or 15-19, wherein modulation of RSK 1 modulates expression proinflammatory factors comprising CCL2/MCP-1, CCL7/MCP-3, and/or CCL8/MCP-2.

[0032] Embodiment 24 is the method of any one of embodiments 1-3, 5-10, or 15-19, wherein modulation of RSK1 modulates expression of progranulin (PGRN) in cells exposed to IL6. [0033] Embodiment 25 is the method of any one of embodiments 1-3, 5-10, or 15-19, wherein modulation of RSK1 modulates phosphorylation of microtubule associated protein (MAPT). [0034] Embodiment 26 is the method of any one of embodiments 1, 2, 4-6, or 11-19, wherein modulation of RSK2 modulates activation of CREN1, ETVl/ER8a, and/or NR4A1/NUR77. [0035] Embodiment 27 is the method of any one of embodiments 1-6, or 11-19, wherein modulation of RSK1 and/or RSK2 modulates phosphorylation of YB1, RPS6, EIF4B, BAD, and/or DAPK1. [0036] Embodiment 28 is the method of any one of the preceding embodiments, wherein the subject is a human.

[0037] Embodiment 29 is the method of embodiment 28, wherein the subject is a human having or suspected of having a neurological disorder.

[0038] Embodiment 30 is the method of embodiment 28, wherein the subject is a human having or suspected of having a neurodegenerative disease.

[0039] Embodiment 31 is a composition comprising an RSK modulator described herein for use in treating a neurological disorder in a subject in need thereof.

[0040] Embodiment 32 is the composition of embodiment 31, wherein the RSK modulator modulates RSK1 and/or RSK2.

[0041] Embodiment 33 is the composition of embodiment 31, wherein the RSK modulator is an RSK 1 modulator.

[0042] Embodiment 34 is the composition of embodiment 31, wherein the RSK modulator is an RSK2 modulator.

[0043] Embodiment 35 is the composition of embodiment 31, wherein the RSK modulator is an RSK1/2 dual modulator.

[0044] Embodiment 36 is the composition of any one of embodiments 31-35, further comprising a pharmaceutically acceptable carrier.

[0045] Embodiment 37 is a use of an agent that modulates RSK1 and/or RSK2 described herein in the manufacture of a medicament for treating a neurological disorder in a subject in need thereof.

[0046] Embodiment 38 is the use of embodiment 37, wherein the agent modulates RSK1. [0047] Embodiment 39 is the use of embodiment 37, wherein the agent modulates RSK2. [0048] Embodiment 40 is the method of embodiment 5 or 6, wherein the small molecule is a compound of Table 1, or a pharmaceutically acceptable salt thereof.

[0049] Embodiment 41 is the use of any one of embodiments 37-39, wherein the agent is a compound of Table 1, or a pharmaceutically acceptable salt thereof.

Brief Description of the Figures

[0050] Figures 1A-1B show expression of RSK1 in human tissues. RSK1 is highly expressed and enriched in whole blood or immune cells but present in various central nervous system (CNS) tissues. [0051] Figures 2A-2B show expression of RSK1 in brain tissue. RSK1 is enriched in mouse (Figure 2 A) microglia and human microglia (Figure 2B).

[0052] Figure 3 shows co-expression of modules identified for PD using transcriptomic data. [0053] Figures 4A-4B show that treatment with RSK1 inhibitors LJI308 and LJH685 rescue 1- methyl-4-phenylpyridine (MPP+) and rotenone induced SH-SY5Y cell death.

[0054] Figure 5 confirms target engagement of RSK1 after treatment with RSK1 inhibitors LJI308 and LJH685. 48 hrs. of incubation with MPP+ increases serine-102 phosphorylation of YB1 (pYBl(S102)) compared to the DMSO control in SH-SY5Y derived neurons. 72h pretreatment with RSK1 inhibitors LJI308 and LJH685 prevents MPP induced serine- 102 phosphorylation of YB1 (pYBl(S102), suggesting chemical inhibition prevents activation of the RSK pathway in this PD model.

Detailed Description

[0055] Reference will now be made in detail to certain embodiments of the invention, examples of which are illustrated in the accompanying drawings. While the invention will be described in conjunction with the illustrated embodiments, it will be understood that they are not intended to limit the invention to those embodiments. On the contrary, the invention is intended to cover all alternatives, modifications, and equivalents, which may be included within the invention as defined by the appended claims.

[0056] The section headings used herein are for organizational purposes only and are not to be construed as limiting the desired subject matter in any way. In the event that any literature incorporated by reference contradicts any term defined in this specification, this specification controls. While the present teachings are described in conjunction with various embodiments, it is not intended that the present teachings be limited to such embodiments. On the contrary, the present teachings encompass various alternatives, modifications, and equivalents, as will be appreciated by those of skill in the art.

A. Definitions

[0057] Unless otherwise stated, the following terms used in the specification and claims are defined for the purposes of this disclosure and have the following meanings.

[0058] As used herein, “RSK” refers to a family of 90-kDa ribosomal S6 kinases (RSKs), which are highly conserved serine/threonine kinases that are downstream effectors of the Ras- extracellular signal-regulated kinase (ERK)/mitogen-activated protein kinase (MAPK) signaling cascade. The RSK family includes four vertebrate isoforms, RSK1-4, and two structurally related homologs, mitogen- and stress-activated kinases (MSKs)-l and 2.

[0059] As used herein, “RSK1” refers to any RSK1 protein that is readily available to a skilled artisan at Genbank. Examples of RSK1 include, but are not limited to proteins, having a GenBank Accession number AL109743.4, AL627313.16 (65630..110901), CH471059.2, EAX07799.1, EAX07800.1,AK092955.1, AK225672.1, AK292722.1, AK294818.1, AK299007.1, AK315730.1, BC014966.1, BC039069.1, BF982517.1, BM836865.1, DC428094.1, L07597.1, AL837508.21 (24057..64567), CH466552.2, AF084468.1, AK132856.1, AK148208.1, AK160571.1, AK167790.1, AK179546.1, AK187369.1, AK187954.1, AK210375.1, AK213589.1, AK214145.1, BC049076.1, BC094470.1, BY226173.1, BY737295.1, CA547794.1, or M28489.1. In some embodiments, an RSK1 is a homolog with at least 95% similarity with any of the abovementioned GenBank Accession numbers for RSK1.

[0060] As used herein, “RSK2” refers to any RSK2 protein that is readily available to a skilled artisan at Genbank. Examples of RSK2 include, but are not limited to, proteins having a GenBank Accession number AB102311.1, AB102312.1, AB102313.1, AB102314.1,

AB 102315.1, AB 102316.1, AB 102317.1, AB 102318.1, AB 102319.1, AB 102320.1,

AB 102321.1, AB102322.1, AB102323.1, AB102324.1, AB102325.1, AB102326.1,

AB 102327.1, AB102328.1, AB102329.1, AB102330.1, AB102341.1, AB102342.1,

AB 102343.1, AB102344.1, AL808146.3 (10499..122961), CH466571.2, AK041476.1,

AK079102.1, AK081329.1, AK154778.1, AK163594.1, AY083469.1, BC008162.1, BC038683.1, BC150156.1, BC150478.1, or CJ123041.1. In some embodiments, an RSK2 is a homolog with at least 95% similarity with any of the abovementioned GenBank Accession numbers for RSK2.

[0061] As used herein, “RSK3” refers to any RSK3 protein that is readily available to a skilled artisan at Genbank. Examples of RSK3 include, but are not limited to, proteins having a GenBank Accession number AL022069.1, AL023775.1, AL159163.40 (2001..82456), AX019387.1, CH471051.2, Z98049.1, AA588877.1, AB073884.1, AB209116.1, AF140710.1, AK027727.1, AK095751.1, AK295674.1, AK307470.1, AK310428.1, BC002363.2, BC011189.1, BF205134.1, BF339000.1 BI836819.1, BQ029058.1, BU160797.1, BU617697.1, DA320139.1, DA328327.1, AC117241.4 (88206..164436), AC122413.4, AC126433.3, AF140707.1 (1296..9608), AF551762.1, CH466693.1, AF141019.1, AJ131021.1, AK019881.1, AK044173.1, AK047061.1 AK050996.1, AK132079.1, AK182754.1, AK191325.1, BC038251.1, BC043064.1, BC051079.1, BC055331.1, BC056946.1, or X57237.1. In some embodiments, an RSK3 is a homolog with at least 95% similarity with any of the abovementioned GenBank Accession numbers for RSK3.

[0062] As used herein, “RSK4” refers to any RSK4 protein that is readily available to a skilled artisan at Genbank. Examples of RSK4 include, but are not limited to, proteins having a GenBank Accession number AC003001.1 (19770..46162), AL022160.1, AL035552.9 (101..149731), AL121867.13 (101..131238), AL354653.26 (146320..173760), AL389887.7 (2001..98724), AL590228.7 (2001..36037), AL593849.4 (2001..17716), AL603626.6 (2001..7689), CH471104.2, CS172421.1, AF184965.1, AK023104.1, AK026301.1, AK310346.1, AK313240.1, BC143647.1, BC143648.1, BQ448025.1, CR536566.1,

BX649629.4 (2000..73503), CH466564.2, CR392009.5 (27494..106097), AK012150.2, AK014822.1, AK049349.1, BC054113.1, BY096109.1, or CN694399.1. In some embodiments, an RSK4 is homolog with at least 95% similarity with any of the abovementioned GenBank Accession numbers for RSK4.

[0063] As used herein, “modulate” (and grammatical variations thereof such as “modulator,” “modulated,” “modulating,” or “modulates”) refers to interfere, inhibit, enhance, reduce, increase, activate, inactivate, change, or affect. For example, a modulator of RSK may interfere with RSK, such that the activity and/or expression level of RSK is inhibited, enhanced, reduced, increased, activated, inactivated, changed, and/or affected. A modulator may interact directly with RSK, thereby modulating RSK. In this way, a modulator of RSK may also modulate a signaling pathway that is downstream of RSK. In another example, a modulator may instead interact with a protein that interacts with or affects RSK, thereby modulating RSK indirectly. [0064] As used herein, “treatment” (and grammatical variations thereof such as “treat” or “treating”) refers to any indicia of success in the treatment or amelioration of the disease or condition. Treating can include, for example, reducing, delaying, or alleviating the severity of one or more symptoms of the disease or condition, or it can include reducing the frequency with which symptoms of a disease, defect, disorder, or adverse condition, and the like, are experienced by a patient. Treat can be used herein to refer to a method that results in some level of treatment or amelioration of the disease or condition and can contemplate a range of results directed to that end, including but not restricted to prevention of the condition entirely.

[0065] As used herein, an “effective amount” of an agent refers to the amount of the agent, at dosages and for periods of time necessary, sufficient to provide a beneficial effect or to otherwise reduce a detrimental non-beneficial event to the individual to whom the composition is administered. One of ordinary skill in the art would understand that the amount, duration, and frequency of administration of an agent described herein to a subject in need thereof depends on several factors including, for example but not limited to, the health of the subject, the specific disease or condition of the subject, the grade or level of a specific disease or condition of the subject, the additional therapeutics the subject is being or has been administered, and the like. [0066] As used herein, a “subject” refers to any member of the animal kingdom. In some embodiments, subject refers to humans. In some embodiments, subject refers to non-human animals. In some embodiments, subjects include, but are not limited to, mammals, birds, reptiles, amphibians, fish, insects, and/or worms. In certain embodiments, the non-human subject is a mammal (e.g., a rodent, a mouse, a rat, a rabbit, a monkey, a dog, a cat, a sheep, cattle, a horse, a primate, and/or a pig). In some embodiments, a subject may be a transgenic animal, genetically engineered animal, and/or a clone. In certain embodiments, the subject is an adult, an adolescent, or an infant. In some embodiments, terms “individual” or “patient” are used and are intended to be interchangeable with “subject.”

[0067] As used herein, the phrase “pharmaceutically acceptable” is employed herein to refer to those compounds, materials, compositions, and/or dosage forms which are, within the scope of sound medical judgment, suitable for use in contact with the tissues of human beings and animals without excessive toxicity, irritation, allergic response, or other problem or complication, commensurate with a reasonable benefit/risk ratio.

[0068] Before describing the present teachings in detail, it is to be understood that the disclosure is not limited to specific compositions or process steps, as such may vary.

[0069] It should be noted that, as used in this specification and the appended claims, the singular form “a”, “an” and “the” include plural references unless the context clearly dictates otherwise. Thus, for example, reference to “a conjugate” includes a plurality of conjugates and reference to “a cell” includes a plurality of cells and the like.

[0070] “Optional” or “optionally” means that the subsequently described event or circumstance may but need not occur, and that the description includes instances where the event or circumstance occurs and instances in which it does not.

[0071] Numeric ranges are inclusive of the numbers defining the range. Measured and measurable values are understood to be approximate, taking into account significant digits and the error associated with the measurement. Also, the use of “comprise”, “comprises”, “comprising”, “contain”, “contains”, “containing”, “include”, “includes”, and “including” are not intended to be limiting. It is to be understood that both the foregoing general description and detailed description are exemplary and explanatory only and are not restrictive of the teachings. [0072] Unless specifically noted in the above specification, embodiments in the specification that recite “comprising” various components are also contemplated as “consisting of’ or “consisting essentially of’ the recited components; embodiments in the specification that recite “consisting of’ various components are also contemplated as “comprising” or “consisting essentially of’ the recited components; and embodiments in the specification that recite “consisting essentially of’ various components are also contemplated as “consisting of’ or “comprising” the recited components (this interchangeability does not apply to the use of these terms in the claims).

[0073] The terms “or a combination thereof’ and “or combinations thereof’ as used herein refers to any and all permutations and combinations of the listed terms preceding the term. For example, “A, B, C, or combinations thereof’ is intended to include at least one of: A, B, C, AB, AC, BC, or ABC, and if order is important in a particular context, also BA, CA, CB, ACB,

CBA, BCA, BAC, or CAB. Continuing with this example, expressly included are combinations that contain repeats of one or more item or term, such as BB, AAA, AAB, BBC, and so forth. The skilled artisan will understand that typically there is no limit on the number of items or terms in any combination, unless otherwise apparent from the context.

[0074] “Or” is used in the inclusive sense, i.e., equivalent to “and/or,” unless the context requires otherwise.

B. Methods of Treatment

[0075] Provided herein are methods of treating a neurological disorder, the method comprising administering to a subject in need thereof an effective amount of an agent that modulates RSK (or “the RSK modulator” hereinafter). The methods of treatment and compositions described herein are for use with a subject having or suspected of having a neurological disorder. In some embodiments, the methods of treatment and compositions are for use with a subject having or suspected of having a neurodegenerative disease. In some embodiments, the subject is human. [0076] In some embodiments, the RSK modulator is administered to a subject in need of treatment for a neurological disorder and the RSK modulator is able to bind to RSK or a homolog thereof and modulate RSK or a homolog thereof. In some embodiments, the modulator inhibits RSK or a homolog thereof. In some embodiments, the neurological disorder is a neurological disorder in which the expression and/or activity levels of RSK detected in the subject is higher than a healthy subject (i.e., a normal control).

[0077] In some embodiments, modulation of RSK may lead to a modulation in the expression levels and/or activity levels of RSK. In some embodiments, modulation of RSK may lead to a decrease in the expression levels and/or activity levels of RSK. In some embodiments, modulation of RSK may lead to a modulation in aggregation of toxicity of RSK. In some embodiments, modulation of RSK may lead to a decrease in aggregation of toxicity of RSK. [0078] The RSK may be chosen from any one of the isoforms of RSK. In many embodiments, the RSK is RSK1 or RSK2.

C. RSK

[0079] The RSK family of proteins are ribosomal S6 kinases (RSKs) involved in signal transduction. Members of the RSK family are activated by the mitogen-activated protein kinase (MAPK)/Ras-extracellular signal-regulated kinase (ERK) signaling cascade. The four vertebrate isoforms of RSK are RSK1, RSK2, RSK3, and RSK4. i. RSK1

[0080] In some embodiments, the RSK is RSK 1 (also known as RPS6KA1). RSK1 transmits phosphorylation signaling downstream of extracellular signal-regulated kinase (ERK1/2) signaling, which is itself activated in response to numerous growth and mitogenic factors (Lavoie et ah, Nat Rev Mol Cell Biol 21(10):607-632 (2020)). RSK1 can translocate to the cell nucleus to phosphorylate nuclear substrates, including transcription factors that subsequently activate or repress gene expression programs.

[0081] MAPK/ERK and RSK signaling are involved in many biological processes, including wound repair, cell proliferation, and development. RSK signaling has been linked to control of autophagy via regulation of the mammalian target of rapamycin (mTOR) signaling. Numerous studies have shown dysfunctional autophagy and lysosome function to be underlying mechanisms of PD, ALS, and related neurodegenerative diseases. In some embodiments, modulation of RSK1 modulates mTOR. In some embodiments, modulation of RSK1 reduces or inhibits mTOR.

[0082] The disordered C-terminal tail of RSK1 contains a phosphorylatable motif, or PBM, which interacts with many different PDZ domain-containing proteins (Gogl et ah, J Mol Biol 431(6): 1234-1249, doi:10.1016/j.jmb.2019.01.038 (2019)). The human genome lists over 266 different PDZ proteins. Depending on the activation state of the cell and the phosphorylation state of RSK1, the PBM domain may switch interactions between different PDZ proteins, thus changing downstream signaling pathways. In some embodiments, modulation of RSK1 modulates signaling pathways that are downstream of RSK1. In some embodiments, modulation of RSK1 modulates the phosphorylation state of its PBM. In some embodiments, modulation of RSK1 alters RSK’s ability to interact with PDZ protein(s). In some embodiments, modulation of RSK1 modulates the activity and/or expression of a PDZ-domain containing protein.

[0083] RSK1 has been shown to phosphorylate elongation factor 2 kinase (eEF2K) and YB1 (Stratford et al., Breast Cancer Res 10: R99, doi: 10.1186/bcr2202 (2008)), thereby inhibiting its activity (Hamdi et al., J Physiol 586 (Pt 14):3623-3640, doi: 10.1113/jphysiol.2011.207175 (2011); Roberts et al., Br J Pharmacol 145(4):477-489, doi: 10.1038/sj.bjp.0706210 (2005); Wang et al., EMBO K 20(16):4370-4379, doi: 10.1093/emboj/20.16.4370 (2001)). In some embodiments, modulation of RSK1 modulates eEF2k activity and/or phosphorylation. In some embodiments, modulation of RSK1 reduces or inhibits eEF2k or YB1 activity and/or phosphorylation.

[0084] RSK1 has been implicated in STATl-mediated pro-inflammatory signaling in human primary macrophages, a cell lineage similar to CNS-resident microglia ( See Figure of Nihira et al., ATVB 38(Suppl_l:Abstract 663) (2018), which is a schematic of RSK1 -mediated STAT1 activation in monocytic lineage cells).

[0085] RSK1 was shown to translocate to the nucleus upon interferon-gamma (IFN-g) stimulation and directly phosphorylate STATE Phosphorylated STAT1 is then capable of turning on expression of multiple proinflammatory factors, including the chemokines CCF2/MCP-1, CCF7/MCP-3, and CCF8/MCP-2. In some embodiments, modulation of RSK1 modulates phosphorylation of STATE In some embodiments, modulation of RSK1 reduces or inhibits phosphorylation of STATE In some embodiments, modulation of RSK1 modulates expression of proinflammatory factors such as CCF2/MCP-1, CCF7/MCP-3, and CCF8/MCP-2. In some embodiments, modulation of RSK1 reduces or inhibits expression of proinflammatory factors such as CCF2/MCP-1, CCF7/MCP-3, and CCF8/MCP-2.

[0086] Increased expression of RSK1 has been associated with neurodegenerative diseases. For example, levels of pERK and its substrate RSK1 are increased in substantia nigra neurons in PD patients (Zhu et al., Am J Pathol 161(6):2087-2098 (2002)) & ERK associates with Fewy bodies, (Ferrer et al., Journal of Neural Transmission 108:1383-1396 (2001); Zhu et al., Am J Pathol 161(6):2087-2098 (2002)). In another example, RSK1 protein levels are also upregulated in AES patients (Hu et al., J Neurochem 85(2):432-420 (2003). In yet another example, a single nucleotide polymorphism (SNP) at rs 17162257 was found to be associated with sporadic ALS in a study of 500 Chinese patients (Xie T et ah, Neurobiology of Aging 35(7): 1778. e9-1778.e23 (2014)). While the nearest gene to this SNP is RSK1, the distance between the SNP and RSKl’s transcriptional start site (TSS) is 72,750 base pairs, which is greater than the conventional threshold for associating a SNP to a gene (Brodie A et al., Nucleic Acids Res 44(13):6046-6054 (2016)).

[0087] Mutations in the PD associated kinase LRRK2, such as G2019S, have been linked to increased dopaminergic neuron vulnerability to pro-inflammatory IFN-g signaling (Panagiotakopoulou et al., Nat Commun 11(1):5163 (2020)) and increased levels of phosphorylated ERLl/2(Reinhard et al., Cell Stem Cell 12(3): {354-367 (2013)). Chemical inhibition of RSK1 reduces expression of progranulin (PGRN) in cells exposed to the proinflammatory cytokine IL6 (Frampton et al., Gut 61(2):268-77 (2012)). Mutations in progranulin are associated with ALS and frontotemporal lobar degeneration (FTLD; Greaves et al., J Neurol 266(8):2075-2086 (2019)). In some embodiments, modulation of RSK1 modulates expression of downstream targets of RSK1 such as PGRN and MAPT. In some embodiments, modulation of RSK1 reduces or inhibits expression of downstream targets of RSK1 such as PGRN and MAPT. In some embodiments, modulation of RSK1 modulates PGRN in cells exposed to IL6. In some embodiments, modulation of RSK1 reduces or inhibits PGRN in cells exposed to IL6. In some embodiments, modulation of RSK1 modulates MAPT. In some embodiments, RSK1 reduces or inhibits MAPT.

[0088] Similarly, in Huntington’s disease, RSK1 levels are upregulated in vivo in mouse models and in vitro models of the disease, together with a change in phosphorylation status. [0089] Further, several studies indicate that a decrease in RSK1 activity is protective. In support, a pan-RSK inhibitor protects mice from EAE via reducing the infiltration of TH1 and TH17 cells into the CNS. (Takada et al., Immunobiology 221(2): 188-192 (2016)). Further, activation of ERK1/2-RPS6KA1 pathway following in vitro ischemia phosphorylates NHE1 and increases its activity and resulting in neuronal damage (Luo et al., Journal of Biological Chemistry 282(38):28274-28284 (2007)).

[0090] Other studies suggest that RSK1 inhibition may be detrimental to cell survival. It may be that activation of RSK1 signaling is implicated in protecting cells from oxidative stress, which involves the upregulation of Cu/ZN SOD after exposure to the natural product Artemisinin (Fang et al., Stem Cell Res Ther 10(1):312 (2019)). Similarly, loss-of-function of RSK1 and RSK2 activity with shRNA and chemical treatments enhance toxicity in an in vitro mutant huntingtin toxicity model, suggesting the protective effect of RSK1 function (Xifro et al., Molecular Neurodegeneration 6:74 (2011)). In some embodiments, modulation of RSK1 modulates aggregation or toxicity of RSK1 and/or ERK. In some embodiments, modulation of RSK1 reduces or inhibits aggregation or toxicity of RSK1 and/or ERK.

[0091] In some embodiments, modulation of RSK1 modulates the expression level and/or activity of RSK1. In some embodiments, modulation of RSK1 inhibits or reduces the expression level and/or activity of RSK1. ii. RSK2

[0092] In some embodiments, the RSK is RSK2 (also known as RPS6KA3). RSK2 acts downstream of ERK (MAPK1/ ERK2 and MAPK3/ERK1) signaling and mediates mitogenic and stress-induced activation of the transcription factors CREB1, ETV1/ER81, and NR4A1/NUR77. RSK2 also regulates translation through RPS6 and EIF4B phosphorylation, and mediates cellular proliferation, survival, and differentiation by modulating mTOR signaling and repressing pro-apoptotic function of BAD and DAPK1 by phosphorylating BAD and DAPK1. RSK2 has been shown to phosphorylate YB1.

[0093] Aberrant RSK2 has been associated with neurological conditions. For example, mutations in RSK2 have been linked to X-linked mental retardation- 19 (OMIM) and a loss-of- function mutation in RSK2 is associated with abnormal increased axon growth in Coffin-Lowry syndrome (CLS) (OMIM; Fischer and Raabe, Front Behav Neuroxci 23:106 (2018); Fim et al., PFOS One 8(9):e74334 (2013)). In another example, overexpression of a constitutively active RSK2 can also cause reduced axon growth (Fischer and Raabe, Front Behav Neuroxci 23:106 (2018)). As observed in RSK1, a use of shRNA that decreases RSK2 activity with shRNA and chemical treatments enhance toxicity in an in vitro mutant huntingtin toxicity model, suggesting the protective effect of RSK1 function (Xifro et al., Molecular Neurodegeneration 6:74 (2011)). [0094] In some embodiments, modulation of RSK2 modulates aggregation or toxicity of RSK2. In some embodiments, modulation of RSK2 reduces or inhibits aggregation or toxicity of RSK2. In some embodiments, modulation of RSK2 modulates the expression level and/or activity of RSK2. In some embodiments, modulation of RSK2 inhibits or reduces the expression level and/or activity of RSK2.

D. Neurological Disorders

[0095] In some embodiments, the neurological disorder is Parkinson’s Disease (PD), Parkinson’s Disease (PD) with Fewy bodies, amyotrophic lateral sclerosis (AFS), frontotemporal dementia (FTD), primary lateral sclerosis (PLS), Charcot-Marie-Tooth (CMT; including type 4J (CMT4J)), and Yunis-Varon syndrome, autophagy, polymicrogyria (including polymicrogyria with seizures), temporo-occipital polymicrogyria, Pick’s disease, dementia with Lewy bodies, Lewy body disease, diseases of neuronal nuclear inclusions of polyglutamine and intranuclear inclusion bodies, disease of Marinesco and Hirano bodies, tauopathy, Alzheimer’s disease, neurodegeneration, spongiform neurodegeneration, peripheral neuropathy, leukoencephalopathy, motor neuropathy, sensory neuropathy, abnormal lysosomal storage syndrome, myotubular myopathy, muscle weakness, cleidocranial dysplasia, Lewy body disease, inclusion body disease, progressive supranuclear palsy, corticobasal syndrome, chronic traumatic encephalopathy, traumatic brain injury (TBI), cerebral ischemia, Guillain-Barre Syndrome, chronic inflammatory demyelinating polyneuropathy, multiple sclerosis, a lysosomal storage disease, Fabry’s disorder, Gaucher’s disorder, Niemann Pick C disease, Tay-Sachs disease, and Mucolipidosis type IV, neuropathy, Coffin-Lowry Syndrome (CLS), X-linked mental retardation disorder (XLMR), intellectual disability, Huntington’s disease, a psychiatric disorder, ADHD, schizophrenia, a mood disorder, major depressive disorder, depression, bipolar disorder I, or bipolar disorder II.

[0096] In some embodiments, the neurological disorder is a neurodegenerative disease. In some embodiments, the neurodegenerative disease is a central nervous system (CNS) neurodegenerative disease. Examples of the neurodegenerative disease include, but is not limited to PD, ALS, FID, Alzheimer’s disease, Huntington’s disease, prion disease, Lewy body disease, Friedreich’s ataxia, or spinal muscular atrophy. In some embodiments, the neurodegenerative disease is PD. In some embodiments, the neurodegenerative disease is amyotrophic lateral sclerosis (ALS).

[0097] In some embodiments, the neurological disorder or neurodegenerative disease is PD. Thus, in some embodiments, a method of treating PD is provided comprising administering to a subject in need thereof an effective amount of an agent that modulates RSK. In some embodiments, the effective amount of said agent inhibits RSK. In some embodiments, the RSK is RSK1 and/or RSK2.

[0098] In some embodiments, the neurological disorder or neurodegenerative disease is ALS. Thus, in some embodiments, a method of treating ALS is provided comprising administering to a subject in need thereof an effective amount of an agent that modulates RSK. In some embodiments, the effective amount of said agent inhibits RSK. In some embodiments, the RSK is RSK1 and/or RSK2. E. Compositions

[0099] Compositions that are useful in the methods described herein include any agent that modulates RSK (i.e., an RSK modulator), wherein the agent is an RSK1 modulator and/or an RSK2 modulator. In some embodiments, the composition comprises an RSK1 modulator. In some embodiments, the composition comprises an RSK2 modulator.

[00100] Compositions that are useful in the methods described herein include any agent that inhibits RSK (i.e., an RSK modulator), wherein the agent is an RSK1 inhibitor and/or an RSK2 inhibitor. In some embodiments, the composition comprises an RSK1 inhibitor. In some embodiments, the composition comprises an RSK2 inhibitor.

[00101] The compositions may further comprise a pharmaceutically acceptable carrier.

[00102] In some embodiments, agents that modulate RSK1 and/or RSK2 for use in the manufacture of a medicament for treating a neurological disorder in a subject in need thereof are provided, optionally wherein the neurological disorder is PD or ALS. In some embodiments, said agents that modulate RSK1 and/or RSK2 inhibit RSK1 and/or RSK2. i. RSK Modulators

[00103] An RSK modulator disclosed herein may have an IC50, Ki, or Kd of less than 500 nM when determined at a physiologically relevant concentration of adenosine triphosphate (ATP). [00104] Examples of molecules known to modulate RSK are disclosed in a journal article by A. Costales et al. Bioorg. Med. Chem. Lett. 24 (2014) 1592-1596, and in US 9,771,366,

WO 2011/060440, US 9,073,926, WO 2011/071716A1, WO 2008/031594, and WO 2013/071217. Some examples of molecules known to modulate RSK include the compounds of Table 1.

[00105] Table 1: Compounds that modulate RSK

and pharmaceutically acceptable salts thereof.

[00106] In some embodiments, the RSK modulator is an RSK1 modulator. In some embodiments, the RSK modulator is an RSK1 inhibitor. In some embodiments, the RSK modulator is an RSK2 inhibitor. In some embodiments, the RSK modulator is an RSK2 inhibitor. In some embodiments, the RSK modulator is an RSK1/RSK2 dual modulator. In some embodiments, the RSK modulator is an RSK1/RSK2 dual inhibitor.

[00107] In some embodiments, the RSK modulator is a small molecule, an antibody, a peptide, an antisense oligonucleotide, a proteolysis targeting chimera (PROTAC), a short hairpin RNA, and an RNAi. In some embodiments, the antibody is a humanized antibody. In some embodiments, the PROTAC comprises a protein of interest (POI) ligand and an E3 ubiquitin ligase (E3) recruiting ligand, wherein the POI ligand and the E3 are linked. In some embodiments, the RNAi is a microRNA, an siRNA, or a shRNA. In some embodiments, the RSK modulator is a small molecule. In some embodiments, the RSK modulator is a small molecule inhibitor. In some embodiments, the RSK modulator is any one of the compounds of Table 1. [00108] In some embodiments, the RSK modulator binds to RSK1 and/or RSK2.

[00109] In some embodiments, the RSK modulator is an ATP-competitive, cell permeable modulator of one, more, or all RSK isoforms. In some embodiments, the ATP-competitive, cell permeable modulator is an inhibitor of one, more, or all RSK isoforms.

[00110] In some embodiments, the RSK modulator is a selective modulator of the RSK family of proteins. In some embodiments, the RSK modulator is a selective inhibitor of the RSK family of proteins. In some embodiments, the RSK modulator does not modulate upstream kinases such as MEK, Raf, and PKC. In some embodiments, the RSK modulator does not inhibit upstream kinases such as MEK, Raf, and PKC.

[00111] In some embodiments, the RSK modulator is an irreversible modulator of RSK1, RSK2, RSK3, RSK4, or any combination thereof. In some embodiments, the RSK modulator is an irreversible inhibitor of RSK1, RSK2, RSK3, RSK4, or any combination thereof. In some embodiments, the RSK modulator binds to RSK1 and/or RSK2.

[00112] In some embodiments, the RSK modulator is an MSK/RSK family kinase modulator.

In some embodiments, the RSK modulator is an MSK/RSK family kinase inhibitor. In some embodiments, the RSK modulator binds with higher affinity for RSK2 over NEK2 and PLK1. [00113] In some embodiments, the RSK modulator is a pan-RSK modulator and binds to RSK proteins including RSK1 and/or RSK2. In some embodiments, the RSK modulator is a pan-RSK inhibitor and binds to RSK proteins including RSK1 and/or RSK2.

[00114] In some embodiments, the RSK modulator is a cell-permeable modulator of p70 ribosomal S6 kinase (S6K1 isoform). In some embodiments, the RSK modulator is a cell- permeable inhibitor of p70 ribosomal S6 kinase (S6K1 isoform). In some embodiments, the RSK modulator binds to S6K1 and/or RSK proteins, including RSK1 and/or RSK2.

[00115] In some embodiments, the RSK modulator is soluble at pH 2 to pH 9.

[00116] In some embodiments, the RSK modulator modulates the expression level and/or the activity of RSK1 and/or RSK2. In some embodiments, the RSK modulator inhibits the expression level and/or the activity of RSK 1 and/or RSK2.

[00117] In some embodiments, modulation of RSK1 results in modulated expression of RSK1. In some embodiments, modulation of RSK1 results in decreased expression of RSK1. In some embodiments, modulation of RSK1 results in a decreased expression level of RSK1 that is at least 10%, at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, or more as compared to an appropriate control. In some embodiments, modulation of RSK1 results in modulated activity of RSK1. In some embodiments, modulation of RSK1 results in decreased activity of RSK1. In some embodiments, modulation of RSK1 results in decreased activity of RSK1 that is at least 10%, at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, or more as compared to an appropriate control.

[00118] In some embodiments, modulation of RSK1 modulates aggregation or toxicity of RSK1 and/or extracellular signal-regulated kinase (ERK). In some embodiments, modulation of RSK1 reduces or inhibits aggregation or toxicity of RSK1 and/or extracellular signal-regulated kinase (ERK). In some embodiments, modulation of RSK1 modulates mammalian target of rapamycin (mTOR) signaling. In some embodiments, modulation of RSK1 reduces or inhibits mammalian target of rapamycin (mTOR) signaling. In some embodiments, modulation of RSK1 modulates phosphorylation to STAT1. In some embodiments, modulation of RSK1 reduces or inhibits phosphorylation to STAT1. In some embodiments, modulation of RSK 1 modulates expression proinflammatory factors comprising CCL2/MCP-1, CCL7/MCP-3, and/or CCL8/MCP-2. In some embodiments, modulation of RSK 1 reduces or inhibits expression proinflammatory factors comprising CCL2/MCP-1, CCL7/MCP-3, and/or CCL8/MCP-2. In some embodiments, modulation of RSK1 modulates expression of progranulin (PGRN) in cells exposed to IL6. In some embodiments, modulation of RSK1 reduces or inhibits expression of progranulin (PGRN) in cells exposed to IL6. In some embodiments, modulation of RSK1 modulates phosphorylation of microtubule associated protein (MAPT). In some embodiments, modulation of RSK1 reduces or inhibits phosphorylation of microtubule associated protein (MAPT).

[00119] In some embodiments, modulation of RSK2 results in modulated expression of RSK2. In some embodiments, modulation of RSK2 results in decreased expression of RSK2. In some embodiments, modulation of RSK2 results in a decrease expression level of RSK2 is at least 10%, at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, or more as compared to an appropriate control. In some embodiments, modulation of RSK2 results in modulated activity of RSK2. In some embodiments, modulation of RSK2 results in decreased activity of RSK2. In some embodiments, modulation of RSK2 results in decreased activity of RSK2 that is at least 10%, at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, or more as compared to an appropriate control.

[00120] In some embodiments, modulation of RSK2 modulates activation of CREN1, ETVl/ER8a, and/or NR4A1/NUR77. In some embodiments, modulation of RSK2 reduces or inhibits activation of CREN1, ETVl/ER8a, and/or NR4A1/NETR77. In some embodiments, modulation of RSK2 modulates phosphorylation of YB 1, RPS6, EIF4B, BAD, and/or DAPK1. In some embodiments, modulation of RSK2 reduces or inhibits phosphorylation of YB 1, RPS6, EIF4B, BAD, and/or DAPK1.

[00121] The control can be determined by those of skill in the art as applicable to the particular situation. In some instances, the control is an industry standard agreed upon by those of skill as being a level or range of levels that is typical of a subject having a neurological disorder before the treatment. In some instances, the control is a reference level of RSK1 or RSK2 from the same individual taken at a time point before the treatment and whether the subject has decreased level of RSK1 or RSK2 after the treatment is determined based on a sample from that same individual taken before the treatment. In some embodiments, levels of RSK1 or RSK2 are measured in the in vitro or in vivo systems. In some embodiments, levels of RSK1 or RSK2 are measured in cells, e.g., motor neuronal cells, in plasma, or in cell culture media. In some embodiments, levels of RSK1 or RSK2 are measured from a plasma sample. In some embodiments, levels of RSK1 or RSK2 are measured from a serum sample.

[00122] In some embodiments, the RSK modulator described herein may be for use in treating a neurological disorder in a subject in need thereof. In some embodiments, the RSK modulator described herein may be for use in treating a neurodegenerative disease in a subject in need thereof. Examples of the neurological disorders and neurodegenerative diseases are disclosed in Section D. Neurological Disorders above.

[00123] In some embodiments, the neurological disorder is a neurological disorder in which the expression and/or activity levels of RSK detected in a subject is higher than a normal control. In some embodiments, the activity level of RSK is measured or determined by the extent of protein phosphorylation by RSK. In some embodiments, the extent of protein phosphorylation by RSK in a subject having a neurological disorder is different than the extent of protein phosphorylation by RSK in a normal control. In some embodiments, the extent of protein phosphorylation by RSK in a subject having a neurological disorder is higher than in a normal control. The normal control can be determined by those of skill in the art as applicable to the particular situation. In some instances, the normal control is an industry standard agreed upon by those of skill as being a level or range of levels that is typical of an individual without an RSK-associated condition. In some instances, the normal control is a reference level of RSK from the same individual taken at a time point and whether the subject has elevated RSK is determined based on a sample from that same individual taken at a different, typically later, time point. [00124] In general, the RSK modulator (or a pharmaceutical composition comprising the same described herein) of the present disclosure is administered in an effective amount by any of the accepted modes of administration for agents that serve similar utilities. Effective amounts of will depend upon numerous factors such as the severity of the disease to be treated, the age and relative health of the subject, the potency of the compound being utilized, the route and form of administration, and other factors. The RSK modulator (or a pharmaceutical composition comprising the same) described herein that can be used in treatment can be formulated and dosages established in a fashion consistent with good medical practice taking into account the disorder to be treated, the condition of the individual subject, the site of delivery, the method of administration and other factors known to practitioners.

[00125] Often, administration of the compounds or pharmaceutical compositions can include routes of administration. Non-limiting examples of administration routes include intravenous, intraarterial, subcutaneous, subdural, intramuscular, intracranial, intrastemal, intratumoral, or intraperitoneally. Additionally, a pharmaceutical composition or compound can be administered to a subject by additional routes of administration, for example, by inhalation, oral, dermal, intranasal, or intrathecal administration. The appropriate formulation and route of administration may be selected according to the intended application.

[00126] Pharmaceutical compositions or agents of the present disclosure can be administered to a subject in need thereof in a first administration, and in one or more additional administrations. The one or more additional administrations can be administered to the subject in need thereof minutes, hours, days, weeks, or months following the first administration. Any one of the additional administrations can be administered to the subject in need thereof less than 21 days, less than 14 days, less than 10 days, less than 7 days, less than 4 days or less than 1 day after the first administration. The one or more administrations can occur more than once per day, more than once per week, or more than once per month. The agents or pharmaceutical compositions can be administered to the subject in need thereof in cycles of 21 days, 14 days, 10 days, 7 days, 4 days, or daily over a period of one to seven days.

Examples

[00127] The following examples are provided to illustrate certain disclosed embodiments and are not to be construed as limiting the scope of this disclosure in any way. Example 1: Identification of Co-expression Modules for Parkinson’s Disease (PD)

[00128] Using a consensus eigengene network, a co-expression module enriched for genes associated with PD was identified. Gene expression data from 5 bulk brain datasets from PD patients (NIH GEO accession numbers GSE20163, GSE20292, GSE7621, GSE20164, and GSE20168) were trained using the methods disclosed in Langfelder and Horvath, BMC Bioinformatics, 9:559 (2008). This network, referred to as network #3901, has 20 gene modules that are grouped into four clusters, each with a stereotyped pattern of gene regulation (Figure 3). Module #2 (a.k.a 3901-2) was identified as enriched for genes associated with PD using genome-wide association studies (GWAS), transcriptome-wide association studies (TWAS), or related studies.

Example 2: Identification of RSK1 and RSK2 as Candidate Targets in PD [00129] RSK1 was identified using a machine learning approach based on Network 3901 of Example 1. 19,797 protein coding genes were organized according 1,269 attributes so that the genes may be characterized. A feature matrix with three different types of attributes was produced. First, basic gene attributes were included, such as biological class (e.g., transcription factor, kinase, and RNA-binding), gene length, and brain tissue specificity. Second, the matrix included differential expression data (log2 fold change and p-value) for each gene that was measured in the five datasets used to construct Network 3901. Third, the matrix included features specific to modules from 3901, such as gene's module membership (measured as kME by the Weighted Gene Coexpression Network software package, Langfelder and Horvath, BMC Bioinformatics, 9:559 (2008)). Using this data, a neural network was trained on a positive set of genes (genes that are genetically associated with PD) and a ranking was produced for every gene based on their similarity to the positive set.

[00130] Using this method, RSK1 ranked #13 out of 19,797 total genes. This indicates that RSK1 has similar features to PD-associated genetic drivers and suggests that RSK1 could provide a potential therapeutic pathway.

[00131] Computational evidence for RSK2 (also known as RPS6KA3) was also examined for small molecule candidates that may inhibit RSK1 and/or RSK2, or RSKs in general. Using the approach described above for RSK1 analysis, RSK2 was ranked #1,695 out of 19,792 genes. A sensitivity analysis measuring the robustness of gene ranks in response to changes in the training data showed that ranks below 2,000 may be significant (not shown). RSK2’s ranking at #1,695 indicates that it may be a target candidate in PD. Further, the module membership score (kME) of RSK2 to the genetically enriched module 3901-2 was 0.62 (a ranking of 1,201 out of 17,422) and its kME to another genetically enriched module 3901-6 was 0.70 (a ranking of 615 out of 17,422). As context, kME values range from -1.0 to +1.0; with positive values indicating positive correlation with the network, and values greater than 0.6 being considered strong members of the network.

Example 3: Identification of STAT1, PGRN, and MAPT as a Candidate Target in PD and ALS

[00132] Using the methods described in Examples 1 and 2 above, STAT1 was identified as a highly ranked gene (in the top 100 of all human genes) based on association with disease gene co expression networks, evidence for functional regulation of disease networks, and human genetics evidence. RSK1 directly phosphorylates and activates STAT1 to promote pro-inflammatory gene expression. In this way, RSK1 mediates neuroinflammation in neurodegenerative diseases such as PD and ALS. Downstream targets of the RSK1 signaling pathway - PGRN (expression reduced under proinflammatory conditions; Frampton et ah, 2012) and MAPT (a direct substrate of the kinase; Virdee et al, 2007) - are also listed in the top 100 candidates in the ALS and PD discovery platforms. RSK1 gene expression is elevated in both PD and ALS patient tissue versus control tissue analyzed as described below (Tables 1 and 2). This observation provides support that RSK1 inhibition may be a therapeutic strategy in PD and ALS.

[00133] Table 2 shows that a modest but consistent up-regulation of RSK1 was observed in PD bulk-tissue substantia nigra and cortex samples versus matched non-neurological controls. “DEX Analysis” is the description of tissue and the name of the patient study from which data was acquired. “Gene” is the ensembl gene name. “Avg Expr” is the average number of reads after regularized log transformation for this gene in all samples for the study. “Log2FC” is the Log2 fold-change comparing expression in PD patient samples to non-neurological controls. Positive values indicate up-regulation in the PD case, while negative values indicate down-regulation. “P- value” is the significance of the log2FC value, as computed by DESeq2 software package. [00134] Table 3 shows that a modest but consistent up-regulation of RSK1 was observed in ALS patient bulk-tissue spinal cord, cortex, and laser dissected samples versus matched controls. See Table 2 definitions above for a description of the columns.

[00135] Table 2: Differential Expression of RSK1 mRNA in Substantia nigra and cortex tissue from Parkinson’s Disease Patients and non-neurological controls.

Table 3: Differential Expression of RSK1 mRNA in spinal cord and cortex from ALS Patients and non-neurological controls.

Example 4: Decreased RSK1 or SNCA Expression Improves HEK293 Cell Viability [00136] Viability of HEK293 cells that stably express alpha synuclein (SNCA, a known PD neurotoxic protein) can be improved with reduction of RSK1 expression. Knockdown of either RSK1 or SNCA rescues the viability of HEK SNCA stable cells treated with DMSO or rotenone (Table 4). Specific RSK1 knockdown was confirmed by RNA-seq data (not shown).

[00137] Table 4 shows knockdown efficiency and percentage of rescue in cells that were transfected with either control shRNA (SNCA) or Target RSK1 and then treated with either no toxin (1% DMSO) or mitochondrial toxin (rotenone; 15 nM) for 48 hours. These values, from a meta-analysis of 6 independent studies show there is robust knockdown efficiency (greater than 50%) with each respective shRNA. Although 100% knockdown efficiency was not observed, knockdown of SNCA results in significant rescue in both DMSO and rotenone conditions. Furthermore, knockdown of RSK1 exhibits significant rescue in both DMSO and rotenone conditions, similar to the positive control, demonstrating RSK1 knockdown rescues viability in SNCA-expressing HEK cells. S-values are the expected fraction of errors and were used to estimate the sign of all effects with greater absolute local false sign rate, which is analogous to q- values (p-value equivalent to the positive False Discovery Rate) (Storey JD, Ann Statist 31(6):2013-2035, doi: 10.1214/aos/1074290335 (2003)). Knockdown (KD) efficiency is reported as the % reduction in target mRNA as assayed by qPCR. Knockdown of SNCA or RSK1 using shRNA in SNCA-expressing HEK293 cells improved cell viability in cells that were treated with rotenone.

Table 4: Transfection of shRNA knockdown plasmids against SNCA or RSK1 rescues viability of HEK SNCA stable cells

Example 5: Decreased RSK1 activity Improves SH-SY5Y Cell Viability [00138] Treatment with RSK inhibitors LJH685 and LJI308 (Figures 4A-4B) improved viability of SH-SY5Y cells treated with rotenone. SH-SY5Y cells were seeded at 30,000 cells/well in a 96 well plate and differentiated for 12 days. SH-SY5Y cells, which are neuroblastoma cells, were differentiated into dopaminergic neuron-like cells. Nine concentrations of RSK1 inhibitors LJI308 and LJH685 were pre-incubated with SH-SY5Y cells for 72 hours followed by 48 hours of incubation with 200 mM MPP+ and 100 nM rotenone. [00139] Treatment with the RSK inhibitors rescued the viability of differentiated SH-SY5Y cells that were treated for 48 hours with MPP+ or rotenone (5 day total treatment of RSK inhibitors). MPP+ is specifically toxic to cells expressing the dopamine transporter. Cell viability was measured using CellTiter-Glo^® Cell Viability Assay (Promega Catalog #G9241). Data are the mean of three technical replicates ± SEM.

[00140] Target engagement of RSK after RSK inhibitor treatment was confirmed in western blot experiments of Y-box protein 1 phosphorylation on the Serine 102 residue (See Stratford et al., Figure 4(e) RSK1 kinase activity leads to increased phosphorylation of its substrate, YB-1 (Y-box binding protein)). SH-SY5Y cells were seeded at 350,000 cells/well in 12 well plate and differentiated for 12 days. 20 pM RSK1 inhibitors LJI308 and LJH685 were pre-incubated with SH-SY5Y cells for 72 hours followed by 48 hours incubation of PBS (Figure 5, left) or 200pM MPP+ (Figure 5, right). Phospho-YBl (Serl02) levels were detected by Western blot using anti- pYBl (Serl02) (C34A2) rabbit mAb (#2900, cell signaling). Total YB1 levels were determined by anti- YB-1 antibody (59-Q) mouse mAb (sc-101198, Santa Cruz Biotechnology). The quantification of the Western blot was normalized to the DMSO/PBS control. The 48 hour treatment of SH-SY5Y dopamine-like neurons with MPP+ demonstrated an increase of pYB 1- S102 levels. The 72 hour pretreatment of SH-SY5Y dopamine-like neurons with 20 pM of RSK inhibitors FJH685 and FJI308 demonstrated a reduction of pYBl-S102 levels under control and MPP induced conditions. These results suggest activation of the RSK pathway and protection from PD toxin induced neuronal death by RSK inhibition.

[00141] The foregoing disclosure has been described in some detail by way of illustration and example, for purposes of clarity and understanding. Therefore, it is to be understood that the above description is intended to be illustrative and not restrictive. The scope of the disclosure should, therefore, be determined not with reference to the above description, but should instead be determined with reference to the following appended claims, along with the full scope of equivalents to which such claims are entitled.

Claims

What is claimed is:

1. A method of treating a neurological disorder, the method comprising administering to a subject in need thereof an effective amount of an agent that modulates RSK1 and/or RSK2.

2. The method of claim 1, wherein the neurological disorder is a neurological disorder in which the expression and/or activity levels of RSK1 and/or RSK2 detected in the subject is higher than a normal control.

3. The method of claim 1 or 2 wherein the agent modulates RSK1.

4. The method of claim 1 or 2 wherein the agent modulates RSK2.

5. The method of any one of claims 1-4, wherein the agent that modulates RSK1 and/or RSK2 is a small molecule, an antibody, a peptide, a PROTAC, an antisense oligonucleotide, or an RNAi.

6. The method of any one of claims 1-5, wherein the agent that modulates RSK1 and/or RSK2 is a small molecule.

7. The method of any one of claims 1-3, 5, or 6, wherein modulation of RSK1 results in decreased expression of RSK1.

8. The method of claim 7, wherein the decreased expression level of RSK1 is at least 10%, at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, or more as compared to an appropriate control.

9. The method of any one of claims 1-3, 5 or 6, wherein modulation of RSK1 results in decreased activity of RSK1.

10. The method of claim 9, wherein the decreased activity of RSK1 is at least 10%, at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, or more as compared to an appropriate control.

11. The method of any one of claims 1, 2, 4-6, wherein modulation of RSK2 results in decreased expression of RSK2.

12. The method of claim 11, wherein the decreased expression level of RSK2 is at least 10%, at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, or more as compared to an appropriate control.

13. The method of any one of claims 1, 2, 4-6, wherein modulation of RSK2 results in decreased activity of RSK2.

14. The method of claim 13, wherein the decreased activity of RSK2 is at least 10%, at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, or more as compared to an appropriate control.

15. The method of any one of claims 1-14, wherein the neurological disorder is Parkinson’s Disease (PD), Parkinson’s Disease (PD) with Lewy bodies, amyotrophic lateral sclerosis (ALS), frontotemporal dementia (FTD), primary lateral sclerosis (PLS), Charcot-Marie-Tooth (CMT; including type 4J (CMT4J)), and Yunis-Varon syndrome, autophagy, polymicrogyria (including polymicrogyria with seizures), temporo-occipital polymicrogyria, Pick’s disease, dementia with Lewy bodies, Lewy body disease, diseases of neuronal nuclear inclusions of polyglutamine and intranuclear inclusion bodies, disease of Marinesco and Hirano bodies, tauopathy, Alzheimer’s disease, neurodegeneration, spongiform neurodegeneration, peripheral neuropathy, leukoencephalopathy, motor neuropathy, sensory neuropathy, abnormal lysosomal storage syndrome, myotubular myopathy, muscle weakness, cleidocranial dysplasia, Lewy body disease, inclusion body disease, progressive supranuclear palsy, corticobasal syndrome, chronic traumatic encephalopathy, traumatic brain injury (TBI), cerebral ischemia, Guillain-Barre Syndrome, chronic inflammatory demyelinating polyneuropathy, multiple sclerosis, a lysosomal storage disease, Fabry’s disorder, Gaucher’s disorder, Niemann Pick C disease, Tay-Sachs disease, and Mucolipidosis type IV, neuropathy, Coffin-Lowry Syndrome (CLS), X-linked mental retardation disorder (XLMR), intellectual disability, Huntington’s disease, a psychiatric disorder, ADHD, schizophrenia, a mood disorder, major depressive disorder, depression, bipolar disorder I, or bipolar disorder II.

16. The method of any one of claims 1-14, wherein the neurological disorder is a neurodegenerative disease.

17. The method of claim 16, wherein the neurodegenerative disease is amyotrophic lateral sclerosis (ALS), frontotemporal dementia (FTD), Alzheimer’s disease, Parkinson’s Disease (PD), Huntington’s disease, prion disease, Lewy body disease, Friedreich’s ataxia, or spinal muscular atrophy.

18. The method of any one of claims 16 or 17, wherein the neurodegenerative disease is amyotrophic lateral sclerosis (ALS).

19. The method of any one of claims 16 or 17, wherein the neurodegenerative disease is Parkinson’s Disease (PD).

20. The method of claim 1-3, 5-10, or 15-19, wherein modulation of RSK1 modulates aggregation or toxicity of RSK1 and/or extracellular signal-regulated kinase (ERK).

21. The method of claim 1-3, 5-10, or 15-19, wherein modulation of RSK1 modulates mammalian target of rapamycin (mTOR) signaling.

22. The method of claim 1-3, 5-10, or 15-19, wherein modulation of RSK1 modulates phosphorylation to STAT1.

23. The method of any one of claims 1-3, 5-10, or 15-19, wherein modulation of RSK 1 modulates expression proinflammatory factors comprising CCL2/MCP-1, CCL7/MCP-3, and/or CCL8/MCP-2.

24. The method of any one of claims 1-3, 5-10, or 15-19, wherein modulation of RSK1 modulates expression of progranulin (PGRN) in cells exposed to IL6.

25. The method of any one of claims 1-3, 5-10, or 15-19, wherein modulation of RSK1 modulatesphosphorylation of microtubule associated protein (MAPT).

26. The method of any one of claims 1, 2, 4-6, or 11-19, wherein modulation of RSK2 modulatesactivation of CREN1, ETVl/ER8a, and/or NR4A1/NUR77.

27. The method of any one of claims 1, 2, 4-6, or 11-19, wherein modulation of RSK1 and/or RSK2 modulates phosphorylation of YB1, RPS6, EIF4B, BAD, and/or DAPK1.

28. The method of any one of the preceding claims, wherein the subject is a human.

29. The method of claim 28, wherein the subject is a human having or suspected of having a neurological disorder.

30. The method of claim 28, wherein the subject is a human having or suspected of having a neurodegenerative disease.

31. A composition comprising an RSK modulator described herein for use in treating a neurological disorder in a subject in need thereof.

32. The composition of claim 31, wherein the RSK modulator modulates RSK1 and/or RSK2.

33. The composition of claim 31, wherein the RSK modulator is an RSK1 modulator.

34. The composition of claim 31, wherein the RSK modulator is an RSK2 modulator.

35. The composition of claim 31, wherein the RSK modulator is an RSK1/2 dual modulator.

36. The composition of any one of claims 31-35, further comprising a pharmaceutically acceptable carrier.

37. A use of an agent that modulates RSK1 and/or RSK2 described herein in the manufacture of a medicament for treating a neurological disorder in a subject in need thereof.

38. The use of claim 37, wherein the agent modulates RSK1.

39. The use of claim 37, wherein the agent modulates RSK2.

40. The method of claim 5 or 6, wherein the small molecule is a compound of Table 1, or a pharmaceutically acceptable salt thereof.

41. The use of any one of claims 37-39, wherein the agent is a compound of Table 1, or a pharmaceutically acceptable salt thereof.