Jolie Huang
Ph.D. Student in Neurosciences, admitted Autumn 2020
All Publications
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C4d, a high-affinity LilrB2 ligand, is elevated in Alzheimer's disease and mediates synapse pruning.
Proceedings of the National Academy of Sciences of the United States of America
2025; 122 (38): e2519253122
Abstract
Synapse pruning sculpts neural circuits throughout life. The human Leukocyte immunoglobulin-like receptor type B2 (LilrB2)/murine Paired immunoglobulin receptor B (PirB) receptors expressed in neurons and complement protein C4 have been separately implicated in pruning. Here, we report that C4d, a C4 cleavage product with unknown function, binds LilrB2/PirB with nanomolar affinity. C4d and LilrB2 colocalize at excitatory synapses in the human cerebral cortex as well as with beta amyloid in Alzheimer's disease (AD). C4d, as well as C4, increase with age and more so in AD. To examine whether C4d-PirB interactions can drive pruning, dendritic spines-the postsynaptic structure of excitatory synapses-were monitored on L5 pyramidal neurons in the mouse cerebral cortex: A significant decrease in dendritic spine density occurred in WT with C4d exposure, but KO of PirB completely prevented this loss. Together, our findings reveal an unexpected physiological role for C4d in pruning and imply that different complement cascade components may collaborate to engage both neuronal and glial-specific effectors of synaptic pruning.
View details for DOI 10.1073/pnas.2519253122
View details for PubMedID 40966293
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TREM1 disrupts myeloid bioenergetics and cognitive function in aging and Alzheimer disease mouse models.
Nature neuroscience
2024
Abstract
Human genetics implicate defective myeloid responses in the development of late-onset Alzheimer disease. A decline in peripheral and brain myeloid metabolism, triggering maladaptive immune responses, is a feature of aging. The role of TREM1, a pro-inflammatory factor, in neurodegenerative diseases is unclear. Here we show that Trem1 deficiency prevents age-dependent changes in myeloid metabolism, inflammation and hippocampal memory function in mice. Trem1 deficiency rescues age-associated declines in ribose 5-phosphate. In vitro, Trem1-deficient microglia are resistant to amyloid-β42 oligomer-induced bioenergetic changes, suggesting that amyloid-β42 oligomer stimulation disrupts homeostatic microglial metabolism and immune function via TREM1. In the 5XFAD mouse model, Trem1 haploinsufficiency prevents spatial memory loss, preserves homeostatic microglial morphology, and reduces neuritic dystrophy and changes in the disease-associated microglial transcriptomic signature. In aging APPSwe mice, Trem1 deficiency prevents hippocampal memory decline while restoring synaptic mitochondrial function and cerebral glucose uptake. In postmortem Alzheimer disease brain, TREM1 colocalizes with Iba1+ cells around amyloid plaques and its expression is associated with Alzheimer disease clinical and neuropathological severity. Our results suggest that TREM1 promotes cognitive decline in aging and in the context of amyloid pathology.
View details for DOI 10.1038/s41593-024-01610-w
View details for PubMedID 38539014
View details for PubMedCentralID 4369837