Pharmacologic Inhibition of ROCK2 Suppresses Amyloid-β Production in an Alzheimer's Disease Mouse Model

• Type of Material: Article
• Authors: Jeremy H. Herskowitz, Emory University; Yangbo Feng, The Scripps Research Institute; Alexa L Mattheyses, Emory University; Chad Hales, Emory University; Lenora A. Higginbotham, Emory University; Duc Duong, Emory University; Thomas J. Montine, University of Washington; Juan C. Troncoso, Johns Hopkins School of Medicine; Madhav Thambisetty, National Institute on Aging; Nicholas Seyfried, Emory University; Allan I Levey, Emory University; James J Lah, Emory University
• Language: English
• Date: 2013-12-04
• Publisher: Society for Neuroscience
• Publication Version: Author Accepted Manuscript (After Peer Review)
• Copyright Statement: © 2013 the authors
• Final Published Version (URL): http://www.jneurosci.org/content/33/49/19086
• Title of Journal or Parent Work: Journal of Neuroscience Nursing
• ISSN: 0270-6474
• Volume: 33
• Issue: 49
• Start Page: 19086
• End Page: 19098
• Grant/Funding Information: J.C.T. was supported by grants from the Johns Hopkins University Alzheimer's Disease Research Center (NIAAG05146) and the Alzheimer's Association (IIRG-09-134090).; N.T.S. is supported by Alzheimer's Association Grant NIRG-12-242297.; We thank the donors of ADR, a program of the BrightFocus Foundation, for support of this research.; This work was supported by the National Institutes of Health through National Institute on Aging (NIA) Grant 5K99AG043552–02 to J.H.H., National Institute of Neurological Disorders and Stroke (NINDS) Grant P30NS055077, and NIA Grants AG025688, P01AG1449, and AG05136.; This research project was supported in part by the Emory University Integrated Cellular Imaging Microscopy Core of the Emory Neuroscience NINDS Core Facilities grant.; This work was supported in part by the NIA Intramural Research Program of the National Institutes of Health.
• Research Categories: Health Sciences, Pathology; Biology, Neuroscience; Health Sciences, Pharmacology

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.