title: Pharmacologic inhibition of ROCK2 suppresses amyloid-β production in an Alzheimer's disease mouse model.
abstract: Alzheimer's disease (AD) is the leading cause of dementia and has no cure. Genetic, cell biological, and biochemical studies suggest that reducing amyloid-β (Aβ) production may serve as a rational therapeutic avenue to delay or prevent AD progression. Inhibition of RhoA, a Rho GTPase family member, is proposed to curb Aβ production. However, a barrier to this hypothesis has been the limited understanding of how the principal downstream effectors of RhoA, Rho-associated, coiled-coil containing protein kinase (ROCK) 1 and ROCK2, modulate Aβ generation. Here, we report that ROCK1 knockdown increased endogenous human Aβ production, whereas ROCK2 knockdown decreased Aβ levels. Inhibition of ROCK2 kinase activity, using an isoform-selective small molecule (SR3677), suppressed β-site APP cleaving enzyme 1 (BACE1) enzymatic action and diminished production of Aβ in AD mouse brain. Immunofluorescence and confocal microscopy analyses revealed that SR3677 alters BACE1 endocytic distribution and promotes amyloid precursor protein (APP) traffic to lysosomes. Moreover, SR3677 blocked ROCK2 phosphorylation of APP at threonine 654 (T654); in neurons, T654 was critical for APP processing to Aβ. These observations suggest that ROCK2 inhibition reduces Aβ levels through independent mechanisms. Finally, ROCK2 protein levels were increased in asymptomatic AD, mild cognitive impairment, and AD brains, demonstrating that ROCK2 levels change in the earliest stages of AD and remain elevated throughout disease progression. Collectively, these findings highlight ROCK2 as a mechanism-based therapeutic target to combat Aβ production in AD.
authors.affiliation: Center for Neurodegenerative Disease, and Departments of Neurology, Cell Biology, and Biochemistry, Emory University School of Medicine, Atlanta, Georgia 30322, Medicinal Chemistry, Translational Research Institute, The Scripps Research Institute, Jupiter, Florida 33458, Department of Pathology, University of Washington, Seattle, Washington 98104, Departments of Pathology and Neurology, Johns Hopkins School of Medicine, Baltimore, Maryland 21205, and Unit of Clinical and Translational Neuroscience and Laboratory of Behavioral Neuroscience, National Institute on Aging, Baltimore, Maryland 21224.
authors.forename: Jeremy H
authors.initials: JH
authors.lastname: Herskowitz
authors.forename: Yangbo
authors.initials: Y
authors.lastname: Feng
authors.forename: Alexa L
authors.initials: AL
authors.lastname: Mattheyses
authors.forename: Chadwick M
authors.initials: CM
authors.lastname: Hales
authors.forename: Lenora A
authors.initials: LA
authors.lastname: Higginbotham
authors.forename: Duc M
authors.initials: DM
authors.lastname: Duong
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Montine
authors.forename: Juan C
authors.initials: JC
authors.lastname: Troncoso
authors.forename: Madhav
authors.initials: M
authors.lastname: Thambisetty
authors.forename: Nicholas T
authors.initials: NT
authors.lastname: Seyfried
authors.forename: Allan I
authors.initials: AI
authors.lastname: Levey
authors.forename: James J
authors.initials: JJ
authors.lastname: Lah
mesh_terms: D000544:Alzheimer Disease / Q000378:metabolism*; D053829:Amyloid Precursor Protein Secretases / Q000037:antagonists & inhibitors; D016229:Amyloid beta-Peptides / Q000037:antagonists & inhibitors / Q000096:biosynthesis*; D016564:Amyloid beta-Protein Precursor / Q000378:metabolism; D000818:Animals; D016282:Aspartic Acid Endopeptidases / Q000037:antagonists & inhibitors; D015153:Blotting, Western; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D002851:Chromatography, High Pressure Liquid; D004247:DNA / Q000235:genetics; D004305:Dose-Response Relationship, Drug; D057809:HEK293 Cells; D006801:Humans; D007150:Immunohistochemistry; D016086:Lentivirus / Q000235:genetics; D051379:Mice; D018613:Microscopy, Confocal; D010957:Plasmids / Q000235:genetics; D013238:Stereotaxic Techniques; D053719:Tandem Mass Spectrometry; D054460:rho-Associated Kinases / Q000037:antagonists & inhibitors*
chemical_list: D016229:Amyloid beta-Peptides; D016564:Amyloid beta-Protein Precursor; D004247:DNA; C515854:Rock1 protein, mouse; C515855:Rock2 protein, mouse; D054460:rho-Associated Kinases; D053829:Amyloid Precursor Protein Secretases; D016282:Aspartic Acid Endopeptidases; C509282:Bace1 protein, mouse