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

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Title: Loss of PILRA promotes microglial immunometabolism to reduce amyloid pathology in cell and mouse models of Alzheimer's disease.
Authors: Weerakkody, Tanya N., Sabelström, Hanna, Andrews, Shan V., Chadarevian, Jean Paul, Chin, Marcus Y., Tatarakis, David, Propson, Nicholas E., Kim, Do Jin, Theolis, Richard, Parico, Gian Carlo G., Misker, Hiwot, Kung, Jennifer E., Bandyopadhyay, Abira, Robles Colmenares, Yaneth, Jackson, Taggra-Nicole, Qerqez, Ahlam N., Balasundar, Srijana, Davis, Sonnet S., Ha, Connie, Ghosh, Rajarshi
Source: Science Translational Medicine; 12/3/2025, Vol. 17 Issue 827, p1-15, 15p
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 protective PILRA G78R gene variant reduces AD risk in apolipoprotein E4 (APOE4) 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. PILRA knockout (KO) in iMG rescued ApoE4-mediated immunometabolic deficits and prevented lipotoxicity through increased lipid storage, improved mitochondrial bioenergetics, and antioxidant activity. PILRA 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 PILRA-dependent microglial functions. AD mice transplanted with human PILRA KO microglia exhibited reduced amyloid pathology and rescued synaptic markers. A high-affinity ligand blocking PILRA antibody phenocopied PILRA KO iMG. These findings suggest that PILRA is a pharmacologically tractable therapeutic target for AD. Editor's summary: Loss-of-function mutations in the gene paired immunoglobulin-like type 2 receptor alpha (PILRA) may have protective effects against Alzheimer's disease (AD), but how PILRA loss affects cellular function remains elusive. Here, Weerakkody et al. challenged human-derived microglia in different inflammatory and neurodegenerative culture conditions and found that knockout (KO) of PILRA boosted lipid storage and catabolism, reduced oxidative stress, and ameliorated immunometabolic deficits. Transplantation of human-derived PILRA KO microglia ameliorated amyloid pathology in a mouse model of AD. The authors developed a high-affinity PILRA-specific antagonist antibody that had similar effects as PILRA KO in cell models, highlighting a potential therapeutic avenue to inhibit this receptor. —Daniela Neuhofer [ABSTRACT FROM AUTHOR]
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Database: Complementary Index
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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 protective PILRA G78R gene variant reduces AD risk in apolipoprotein E4 (APOE4) 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. PILRA knockout (KO) in iMG rescued ApoE4-mediated immunometabolic deficits and prevented lipotoxicity through increased lipid storage, improved mitochondrial bioenergetics, and antioxidant activity. PILRA 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 PILRA-dependent microglial functions. AD mice transplanted with human PILRA KO microglia exhibited reduced amyloid pathology and rescued synaptic markers. A high-affinity ligand blocking PILRA antibody phenocopied PILRA KO iMG. These findings suggest that PILRA is a pharmacologically tractable therapeutic target for AD. Editor's summary: Loss-of-function mutations in the gene paired immunoglobulin-like type 2 receptor alpha (PILRA) may have protective effects against Alzheimer's disease (AD), but how PILRA loss affects cellular function remains elusive. Here, Weerakkody et al. challenged human-derived microglia in different inflammatory and neurodegenerative culture conditions and found that knockout (KO) of PILRA boosted lipid storage and catabolism, reduced oxidative stress, and ameliorated immunometabolic deficits. Transplantation of human-derived PILRA KO microglia ameliorated amyloid pathology in a mouse model of AD. The authors developed a high-affinity PILRA-specific antagonist antibody that had similar effects as PILRA KO in cell models, highlighting a potential therapeutic avenue to inhibit this receptor. —Daniela Neuhofer [ABSTRACT FROM AUTHOR]
ISSN:19466234
DOI:10.1126/scitranslmed.adw7428