The contribution of hypoxia inducible factor-1-dependent glycolysis in lung interstitial macrophages to the pathobiology of schistosomiasis-induced pulmonary hypertension.

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Project Summary/Abstract Schistosomiasis-induced pulmonary hypertension (Sch-PH) is globally the most common cause of pulmonary arterial hypertension (PAH), and its classification as a “neglected tropical disease” underscores the large unmet need in understanding the disease pathobiology and developing effective treatments. Although accumulating data support the likely contribution of the transcription factor hypoxia inducible factor-1 (HIF-1) and HIF-1-regulated glycolysis to the pathogenesis of PH, their significance in Sch-PH is largely unknown. This proposal examines the potential role of HIF-1-dependent glycolysis in promoting Sch-PH, specifically in lung interstitial macrophages (IMs). Available data demonstrate increased pulmonary perivascular infiltration of IMs in both humans and experimental mice with Sch-PH; increased transcription of HIF-1-associated genes encoding glycolytic enzymes in murine lung IMs with Sch-PH; and a protective effect of HIF-1α deletion in LsyM+ myeloid cells against murine Sch-PH. Building upon these key insights, this proposal will test the hypothesis that HIF-1- dependent glycolysis in perivascular lung IMs critically contributes to the development of Sch-PH. Of the three potential growth-promoting mechanisms of glycolysis--lactate fermentation, the pentose phosphate pathway, and the mitochondrial Krebs cycle--the potential mechanistic link between lactate and pulmonary artery smooth muscle cell (PASMC) proliferation will be additionally examined. Two aims are proposed. Aim 1 will determine necessity and sufficiency of lung IM HIF-1α stabilization in Sch-PH by conditionally deleting and stabilizing HIF- 1α in IMs of transgenic mice. The effect of lactate dehydrogenase A (LDH-A; an enzyme responsible for lactate fermentation) deletion and oxamate (LDH-A inhibitor) treatment on Sch-PH severity will be examined. Aim 2 will spatiotemporally phenotype lung IMs, quantify their glucose metabolism, and test, using co-culture, if lung IM- derived lactate induces a pro-proliferative, pro-fibrogenic phenotype in PASMCs. Completion of the project will clarify how glucose metabolism in lung IMs contributes to Sch-PH pathobiology. The proposed career development plan was designed with the ultimate goal of supporting the applicant’s successful transition to independence as a clinician-scientist, in the field of pulmonary vascular metabolism. The plan leverages the combined expertise of his mentors and advisors in basic-translational research, their commitment to mentorship, and the collective resources for research and professional development at UCSF. In the five years of training, the applicant will acquire proficiency in key experimental approaches (spatially resolved proteomics; flow cytometry and cell sorting; Seahorse metabolic assay; mass spectrometry; and confocal microscopy), develop data analytical skills, disseminate his findings, and refine grantsmanship, collectively positioning him as an expert investigator in the field of pulmonary vascular metabolism.