Loss of PILRA promotes microglial immunometabolism to reduce amyloid pathology in cell and mouse models of Alzheimer's disease.

Abstract

The Alzheimer's disease (AD) genetic landscape identified microglia as a key disease-modifying cell type. Paired immunoglobulin-like type 2 receptor alpha (PILRA) is an immunoreceptor tyrosine-based inhibitory motif domain-containing inhibitory receptor, expressed by myeloid cells such as microglia. The known protectiveG78R gene variant reduces AD risk in() carriers and is enriched in a cohort of healthy centenarians. However, mechanisms underlying protective effects in microglia are undefined. Here, we identified biological functions of PILRA in human induced pluripotent stem cell-derived microglia (iMG) and chimeric AD mice.knockout (KO) in iMG rescued ApoE4-mediated immunometabolic deficits and prevented lipotoxicity through increased lipid storage, improved mitochondrial bioenergetics, and antioxidant activity.KO also enhanced microglial chemotaxis and attenuated inflammation. With pharmacological inhibitor studies, we showed that peroxisome proliferator-activated receptor and signal transducer and activator of transcription 1/3 mediated-dependent microglial functions. AD mice transplanted with humanKO microglia exhibited reduced amyloid pathology and rescued synaptic markers. A high-affinity ligand blocking PILRA antibody phenocopiedKO iMG. These findings suggest that PILRA is a pharmacologically tractable therapeutic target for AD.