Human Immunodeficiency Virus Transgene Expression (HIV‐1 TG) Decreases MicroRNAs Targeting 5‐Lipoxygenase (ALOX5) and Increases Endothelial Dysfunction
Authors: Kang Bum‐Yong , Chang Sarah , Ma Jing , Hart C. Micheal , Sutliff Roy L. 
Published: November 2023

Rationale

Approximately 1.2 million Americans have been infectedwith human immunodeficiency virus (HIV‐1). Among the HIV‐1‐associated spectrumof cardiovascular disorders, pulmonary hypertension (PH) causes high morbidityand mortality. The mechanismsunderlying this increased susceptibility of HIV patients to develop PH have yetto be defined. We previously demonstrated that 5‐lipoxygenase (ALOX5) is apotential mediator in HIV‐induced PH (HIV‐PH). microRNAs (miRNAs or miR), play a pivotal role as post‐transcriptional gene regulatorsthat are differentially expressed during development and disease. However,the role of miRNAs in HIV‐PH pathogenesis remainsincompletely defined. We hypothesizedthat HIV‐mediated miRNAs that target ALOX5 expression may contribute to endothelialdysfunction in HIV‐PH.

Methods and Results

To define pulmonary vascular derangements in HIV‐PH, rightventricular systolic pressure and right ventricular hypertrophy (RVH) weremeasured in HIV‐1 transgene expression (HIV‐1 TG) mice and littermate control (CON)mice. Male HIV‐1 TG mice (age 8–12 weeks) spontaneously develop PH. HIV‐1 TG andCON mice were exposed to normoxia or hypoxia (10% O2) for 3‐weeks. Chronichypoxia exacerbates PH in HIV‐1 TG mice. Additionally, to examine ALOX5 levels,qRT‐PCR and Western blot analysis was performed. Our results show that lungsfrom HIV‐1 TG mice had increased ALOX5 mRNA and protein levels compared to CONmice. To examine potential miRNAs that regulate ALOX5 shared between human,mouse, and rat species, a bioinformatics approach using multiple predictionalgorithms (microRNA.org, miRDB, and TargetScan 7.1) was employed, and bindingsites for miRNAs in the 3′UTR of ALOX5 were identified. This analysis indicatedmiR‐7, miR‐29a, miR‐134, and miR‐193a as potential regulators of ALOX5. Toexamine whether these putative miRNAs targeting ALOX5 were downregulated in lungsof HIV‐1 TG mice, total RNAs and miRNAs were isolated from lungs of CON andHIV‐1 TG mice and then qRT‐PCR analysis was performed. Levels of lung miR‐7,miR‐29a, miR‐134, and miR‐193a were decreased in HIV‐1 TG mice compared to CON mice.Decreases in these miRNAs paralleled ALOX5 upregulation in lungs from HIV‐1 TG mice. To examine HIV‐1‐triggered endothelialdysfunction, markers of endothelial dysfunction, such as C‐C Motif ChemokineLigand 2 (CCL2) and selectin P (P‐SEL) levels were examined using qRT‐PCR. Adhesionmolecule expression is increased in HIV‐1 TG mouse lungs. These results suggestthat HIV‐induced reductions in miR‐7, miR‐29a, miR‐134, and miR‐193a contributeto increases in ALOX5 levels and endothelial dysfunction.

Conclusion

These findings suggest that HIV‐inducedreductions in miRNAs upregulate ALOX5 and increase endothelial dysfunction. These HIV‐regulated miRNAs may play animportant role in HIV‐PH.

Support or Funding Information

Supported by Atlanta VA Merit Review 1I01BX001910 (CMH), NIH HL102167 (RLS and CMH),and AHA‐SDG 13SDG14150004 (BYK).