Schedule of Events | Symposia

Validating Microglia Cell Line HMC3 to Study the B7-1/p75NTR Interaction

Poster Session E - Monday, March 31, 2025, 2:30 – 4:30 pm EDT, Back Bay Ballroom/Republic Ballroom

Emmanuel Makinde^1,2, Hrshita Das², Matthew Houpert², Bruce Carter²; ¹New York University Center for Neural Science, ²Vanderbilt University Medical Center: Department of Biochemistry

The neuroimmune response is crucial to understanding neurodegenerative disease. Microglia are motile brain resident macrophages that surveil the brain, phagocytose pathogens, and release signaling molecules to regulate the tissue microenvironment. Microglia activity increases following the recognition of damage-associated molecular patterns (DAMPs), engulfment of pathogens or dying cells, and response to/production of pro- and anti-inflammatory cytokines to modulate inflammation. T-cells are also major players during the immune response. Cytotoxic T-cells perforate pathogens while helper T-cells support other immune cells. T-cell activation requires detection of two proteins on the microglia membrane: an antigen and a costimulatory factor called B7-1. Recent research identified a primate-specific interaction between the p75 neurotrophin receptor (p75NTR) and the B7-1 protein that contributes to the degradation of synapses in hippocampal neurons. Due to the primate-specificity of this interaction, we chose the Human Microglial Clone 3 (HMC3). The mechanism of the B7-1/p75NTR interaction is unknown. It is also unknown whether the HMC3 cell line is suitable for studying this interaction. In this study, we performed western blots and immunocytochemistry to study B7-1, and markers of inflammation and microglia. We observed increased B7-1 and Iba1 expression in HMC3 cells following lipopolysaccharide treatment, indicating that these cells appropriately respond to inflammatory stimuli. Interestingly, we also found that NLRP3 expression increases with lower doses of LPS. Validating this cell line will enable subsequent studies to investigate microglia-neuron cocultures under inflammatory conditions to clarify the mechanisms of this B7-1/p75NTR interaction, why it leads to synapse degradation, and further, neurodegenerative diseases.

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