Abstract 15659: Development of Novel EMAP-II Neutralizing Antibody Therapy for HIV-Associated Pulmonary Hypertension via Abrogation of HIV-Nef Induced Pulmonary Endothelial Damage

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Rationale: People living with HIV experience increased rates of cardiovascular co-morbidities including pulmonary hypertension (600-fold higher prevalence) despite immediate prescription of combined antiviral therapy (ART) upon HIV diagnosis. Previously, we reported that the virally encoded HIV-Nef protein persists in extracellular vesicles (EV) isolated from bronchoalveolar lavage fluid of aviremic HIV patients on ART. Interestingly, Nef-positivity correlated with increased EMAPII levels, a cellular protein which when released extracellularly specifically amplifies endothelial apoptosis. We hypothesize that Nef-EMAPII signaling axis induces endothelial apoptosis and senescence, which could give rise to apoptosis-senescence-resistant, plexiform lesion-forming endothelial cells. Methods and Results: Co-culture with Nef EV producing SupT1 T-cells induces endothelial senescence quantified using senescence associated marker-p16INK4a (p<0.001) which corresponds to increased EMAPII surface expression. Nef induced endothelial senescence as quantified by β-Galactosidase activity was blocked with EMAPII neutralizing antibody (Fig). Transgenic mice with endothelium specific Nef expression had elevated EMAP II surface expression. Two-dose injection of EMAPII neutralizing antibodies (1 mg/mouse, sc) abrogates apoptosis induction as determined by cleaved caspase 3+ pulmonary endothelial cells (p<0.001). Furthermore, Nef Tg mice derived pulmonary endothelial cells had reduced colony formation (p<0.001) which is being tested with EMAPII neutralization as a therapeutic agent. Conclusion: Nef induced apoptosis and cellular senescence can be targeted with EMAP II neutralizing antibodies both in vitro and in vivo . These data suggest that A) Nef can give rise to apoptosis-senescence-resistant plexiform lesion forming endothelial cells and B) neutralizing EMAPII antibodies can be employed to block progression of PAH.