Epigenetic regulation of microglial identity and function by ARID5B in alzheimer's disease

The National Institute on Aging awarded The Trustees of Columbia University in the City of New York $100,228 on February 18, 2027, under the Aging Research program (CFDA 93.866) for epigenetic regulation research on microglial dysfunction in Alzheimer's disease.

The award funds laboratory research investigating how the protein ARID5B regulates histone modifications that influence microglial identity and function in Alzheimer's disease pathogenesis. The recipient will use CRISPR/Cas9 and CRISPR activating gene-editing techniques to create ARID5B knockout and overexpression models in human microglial cell line 3 (HMC3) and induced pluripotent stem cell–derived microglia. Aim 1 employs chromatin immunoprecipitation sequencing and assay for transposase-accessible chromatin sequencing to identify microglial subtypes with altered histone H3 lysine 9 dimethylation modifications in edited cell lines. The research tests the hypothesis that ARID5B regulates the balance between repressive and activating histone modifications on downstream genes that influence microglial transcriptional states and disease-associated microglial phenotypes.

The work is performed in New York, New York. The period of performance runs from February 18, 2027, through August 31, 2028. This is a Project Grant, a standard assistance type under the Aging Research program supporting biomedical research directed toward understanding aging and age-related diseases including Alzheimer's disease and its related dementias.

Abstract

Alzheimer's disease (ad) is a devastating neurodegenerative condition characterized by cognitive decline and chronic neuroinflammation, and despite the modern standard of care, only has one FDA approved intervention. With microglial dysfunction emerging as a central driver of disease progression, recent studies from our lab have highlighted the role of epigenetic regulation, particularly histone modifications such as histone H3 lysine 9 dimethylation (H3K9ME2) and acetylation (H3K9AC), in shaping microglial identity and behavior in the context of ad. Our preliminary work has identified ARID5B, whose encoded proteins create a demethylase complex with H3K9ME2, as a critical factor in modulating microglial transcriptional states. ARID5B appears to counteract repressive chromatin structures by targeting H3K9ME2 on downstream genes, enabling microglia to transition into disease-associated microglia states (DAM) that may play protective or pathological roles in ad. However, the specific mechanisms by which this ARID5B-mediated chromatin and heterochromatin remodeling drives microglial phenotypes to ad pathology remain unclear. This proposal will test my hypothesis that ARID5B regulates the balance between repressive and activating histone modifications of downstream genes which influence microglial identity and function in ad. I will utilize crispr/CAS9 and crispr activating (crispra) to create ARID5B gene-edited knockout (KO) and overexpression in vitro human microglial cell line 3 (HMC3) and induced pluripotent stem cell (ipsc) derived microglia (IMG). In aim 1, i will use chromatin immunoprecipitation sequencing (chip-SEQ) and assay for transposase-accessible chromatin sequencing (atac-SEQ) to then identify predicted microglial subtypes with upregulation of H3K9ME2 modifications in ARID5B crispr/CAS9 knockout and downregulation in ARID5B crispra cells. In aim 2, i will integrate single-cell RNA sequencing of the ARID5B KO and overexpression in vitro microglia to determine how ARID5B-driven epigenetic changes influence microglial transcription states and then observe whether these changes contribute to DAM-like phenotypes linked to ad pathology. I will then examine the functional influence of ARID5B-mediated epigenetic changes on microglia and whether they are associated with microglial subtypes that exhibit altered cytokine production and phagocytic capacity. This project will investigate how ARID5B modulates microglial identity and behavior through chromatin remodeling, providing critical insights into the cellular and molecular mechanisms driving microglial transitions in ad.