People living with HIV (PLWH) face a growing burden of chronic diseases, owing to the combinations of aging, environmental triggers, lifestyle choices, and virus-induced chronic inflammation. The rising incidence of pulmonary vascular diseases represents a major concern for PLWH. The study of HIV-associated pulmonary vascular complications ideally requires a strong understanding of pulmonary vascular cell biology and HIV pathogenesis at the molecular level for effective applications in infectious diseases and vascular medicine. Active HIV infection and/or HIV proteins disturb the delicate balance between vascular tone and constriction, which is pivotal for maintaining pulmonary vascular health. One of the defining features of HIV is its high genetic diversity owing to several factors including its high mutation rate, recombination between viral strains, immune selective pressures, or even geographical factors. The intrinsic HIV genetic diversity has several important implications for pathogenic outcomes of infection and the overall battle to combat HIV. Challenges in the field present themselves from two sides of the same coin: those imposed by the virus itself and those stemming from the host. The field may be advanced by further developing in vivo and in vitro models that are well described for both pulmonary vascular diseases and HIV for mechanistic studies. In essence, the study of HIV-associated pulmonary vascular complications requires a multidisciplinary approach, drawing upon insights from both infectious diseases and vascular medicine. In this review article, we discuss the fundamentals of HIV virology and their impact on pulmonary disease, aiming to enhance the understanding of either area or both simultaneously. Bridging the gap between preclinical research findings and clinical practice is essential for improving patient care. Addressing these knowledge gaps requires interdisciplinary collaborations, innovative research approaches, and dedicated efforts to prioritize HIV-related pulmonary complications on the global research agenda.

The SARS-CoV-2 pandemic provides a natural opportunity for the collision of coronavirus disease-2019 (COVID-19) with chronic infections, which place numerous individuals at high risk of severe COVID-19. Infection with Human Immunodeficiency Virus (HIV), a global epidemic, remains a major public health concern. Whether prior HIV+ status exacerbates COVID-19 warrants investigation. Herein, we characterized the impact of SARS-CoV-2 in human bronchial epithelial cells (HBECs) previously exposed to HIV. We optimized the air-liquid interface (ALI) cell culture technique to allow for challenges with HIV at the basolateral cell surface and SARS-CoV-2 spike protein on the apical surface, followed by genetic analyses for cellular stress/toxicity and innate/adaptive immune responses. Our results suggest that the IL-10 pathway was consistently activated in HBECs treated with spike, HIV, or a combination. Recombinant spike protein elicited COVID-19 cytokine storms while HIV activated different signaling pathways. HIV-treated HBECs could no longer activate NF-kB, pro-inflammatory TRAF-6 ubiquitination nor RIP1 signaling. Combinations of HIV and SARS-CoV-2 spike increased gene expression for activation of endoplasmic reticulum-phagosome pathway and downregulated non-canonical NF-kB pathways that are key in functional regulatory T cells and RNA Polymerase II transcription. Our in vitro studies suggest that prior HIV infection may not exacerbate COVID-19. Further in vivo studies are warranted to advance this field.

Background: Human Immunodeficiency Virus (HIV) infections remain a source of cardiopulmonary complications among people receiving antiretroviral therapy. Still to this day, pulmonary hypertension (PH) severely affects the prognosis in this patient population. The persistent expression of HIV proteins, even during viral suppression, has been implicated in vascular dysfunction; however, little is known about the specific effects of these proteins on the pulmonary vasculature. This study investigates the impact of Nef variants derived from HIV-positive pulmonary hypertensive and normotensive donors on pulmonary vascular cells in vitro. Methods: We utilized well-characterized Nef molecular constructs to examine their effects on cell adhesion molecule gene expression (ICAM1, VCAM1, and SELE), pro-apoptotic gene expression (BAX, BAK), and vasoconstrictive endothelin-1 (EDN1) gene expression in endothelial nitric oxide synthase (eNOS) nitric oxide and the production and secretion of pro-inflammatory cytokines over 24, 48, and 72 h post-transfections with Nef variants. Results: HIV Nef variants SF2, NA7, and PH-associated Fr17 and 3236 induced a significant increase in adhesion molecule gene expression of ICAM1, VCAM1, and SELE. Pulmonary normotensive Nef 1138 decreased ICAM1 gene expression, but had increased VCAM1. PH Nef ItVR showed a consistent decrease in ICAM1 and no changes in SELE and VCAM1 expression. Further gene expression analyses of pro-apoptotic genes BAX and BAK demonstrated that Nef NA7, SF2, normotensive Nef 1138, and PH Nef Fr8, Fr9, Fr17, and 3236 variants significantly increased gene expression for apoptosis. Normotensive Nef 1138, as well as PH Nef Fr9 and ItVR, all displayed a statistically significant decrease in BAX expression. The expression of EDN1 had a statistically significant increase in samples treated with Nef NA7, SF2, normotensive Nef 2044 and PH Nef 3236, Fr17, and Fr8. Notably, PH-associated Nef variants sustained pro-inflammatory cytokine production, including IL-2, IL-4, and TNFα, while anti-inflammatory cytokine levels remained insufficient. Furthermore, eNOS was transiently upregulated by all Nef variants except for normotensive Nef 2044. Conclusions: The distinct effects of Nef variants on pulmonary vascular cell biology highlight the complex interplay between Nef, host factors, and vascular pathogenesis according to the variants.