Exploring Alzheimer's Therapeutics

About This Grant

Significance to VA: Based on our recent reported search criteria for mild cognitive impairment (MCI) and Alzheimer's disease (AD) from electronic health records (EHR) within Veterans Affairs Healthcare System (VAHS), we identified 339,007 Veterans with MCI and 572,063 Veterans with AD, but there is no effective, safe therapy for MCI and AD. The newly FDA approved anti-amyloid antibody therapies (AAT) have limited effects on halting cognitive decline and exhibit serious side effects of cerebral hemorrhages. Innovation and Impact: We propose to test a potent Rho-associated coiled-coil kinase (ROCK) 1 and 2 inhibitor as a novel AD therapeutic agent, based on our findings that prescriptions of ROCK inhibitor were associated with a ~50% lower risk of developing MCI and AD, compared to non-users, adjusted with age, sex and comorbidities from 25 million Veterans' medical records. We will use AD patient-derived induced pluripotent stem (iPS) cell-differentiated human neurons and three AD mouse models to perform proof-of- concept preclinical studies. We will also perform proteomics and snRNAseq analyses of mouse brains treated with ROCK inhibitors to identify molecular changes. Specific Aims: Aim 1. To evaluate the efficacy of ROCK inhibition in AD mouse models and human neurons. Pharmacokinetic-pharmacodynamics (PK-PD) relationship will be established in mice after chronic dosing via oral gavage or highly palatable foods mixed with ROCK inhibitor to quantify reduction in neurodegeneration, astrogliosis, microgliosis, and memory impairment in 3 AD mouse models. We will also use isogenic iPS cells carrying either familial AD (FAD) mutant or wild-type PSEN1 and then differentiate them into neuro-spheroids. Outcomes from PSEN1 mutant iPS cells will be compared to those from Psen1 Knock-In mice. Aim 2. To identify molecular changes following ROCK inhibition in AD mouse models and human neurons. We will identify changes of proteins related to Tau phosphorylation (e.g. GSK3β), Aβ clearance (e.g. clusterin), pro- and anti-inflammatory cytokine and chemokines, gliosis, apoptosis and neuronal loss (e.g. AKT1). We will profile plasma and brain proteomics of AD mice after chronic dosing and will identify transcriptomic changes using snRNAseq. We will determine whether changes in proteomics and transcriptomics correlate with clinic-pathological outcomes in these mutant mice following ROCK inhibition. Methodology: We will use isogenic iPS cells carrying either an FAD mutant or wild-type PSEN1 and differentiate them into neuro-spheroids. We will also use wild-type mice and three AD mouse models for PK-PD analyses of the ROCK inhibitor, based on their relevant pathological phenotypes, PS19 (overexpressing mutant Tau), Psen conditional double knockout mice (increased pTau), and Psen1 L435F knock-in (KI) mice (increased Aβ42/40 ratio and amyloid pathology). Conventional biochemical analysis and cutting edge mass spectrometry-based proteomic profiling and snRNAseq will be used to obtain and integrate outcomes from mouse brains, such as levels of pathological proteins, astrogliosis, microgliosis, neurodegeneration, and memory impairment in AD mouse models. Path to Translation/Implementation: Our repurposed FDA-approved drug in this study derives from the analysis of large quantities of VA clinical records and shows little harmful side effects in clinical uses. We will execute our in vivo proof-of-concept studies under chronic dosing paradigms. We hope to translate our findings to future drug development by performing toxicity studies in rats and further seeking FDA approval for future clinical trials to test its safety and efficacy as a repurposed AD drug.