Abstract 4120480: HIV-Nef extracellular vesicles utilize the novel Btk-NFκB-MerTK signaling axis to impair macrophage efferocytosis and promote atherosclerosis: A multiomics study

Background: People living with HIV (PLWH) on anti-retroviral therapy remain at risk for cardiovascular diseases, including atherosclerosis. We hypothesized that persistent viral protein (HIV-Nef) in extracellular vesicles (EVs) modulate macrophage heterogeneity to impair atheroprotective efferocytosis to accelerate cardiovascular disease. Methods and Results: Macrophage heterogeneity was characterized in human primary macrophages (50,931 cells; 4 donors) stimulated with EVs engineered to contain HIV-Nef by simultaneous scRNAseq and scATACseq. Among 16 clusters (Fig.1A), two inflammatory Nef dominant clusters were characterized using gene set enrichment analysis. Gene regulatory network analysis of scRNAseq (pySCENIC) and transcription factor footprinting analysis of sc-ATACseq (ChromVar) suggest elevated NFκB activation in these clusters. Whole cell and sub-cellular compartmentalized proteomics of nucleus, cytosol, cell surface and secreted EVs indicate changes in immune response related biological pathways. Network analysis of our multi-omics data predicts Bruton Tyrosine Kinase (Btk) signaling as a potential contributor to Nef induced macrophage dysregulation. Pathway enrichment analysis of these multiomics dataset suggest Nef influences atheroprotective efferocytosis through the Btk-NFκB signaling axis. Spectral flow cytometry, high content imaging and multiplexed qPCR showed reduction in key effector of efferocytosis, MerTK. Btk inhibition using siRNA, reversible and irreversible Btk inhibitors restored MerTK expression and rescued efferocytosis. Importantly, CRISPRa based overexpression of MerTK in human primary macrophages rescued Nef impaired efferocytosis. Injection of HIV-Nef EVs into male and female C57BL6/J mice impaired efferocytosis of peritoneal and bone marrow derived macrophages which was rescued with Btk inhibition in vivo . Critically, injection of HIV-Nef EV into male and female Ldlr -/- enhanced atherogenesis with larger aortic wall thickness and necrotic core (Fig.1B). Conclusion: Persistent Nef in EV in PLWH may modulate macrophage heterogeneity to impair efferocytosis. These findings may help develop novel atheroprotective therapies by restoring macrophage efferocytosis.