Mitochondrial Rieske iron-sulfur protein is a crucial molecule in COPD-associated pulmonary hypertension

Abstract

Pulmonary hypertension (PH) often occurs in chronic obstructive pulmonary disease (COPD) and is the major cause of death in COPD patients. Molecular mechanisms for PH in COPD remain poorly understood, and clinical treatments are neither specific nor effective. Cigarette and e-cigarette smoking (CS) account for up to 90% of COPD cases, in which nicotine is the major active component and causes COPD-like cellular responses; moreover, hypoxia is a known key factor in the development of PH. In this study, we aim to develop a PH in COPD animal model and determine the underlying molecular mechanisms. Our findings revealed that co-exposure of nicotine (or CS) and hypoxia synergistically elevated PH (i.e., right ventricular pressure and weight) compared to nicotine, CS, or hypoxia alone. We also found that mitochondrial reactive oxygen species ([ROS] m ), assessed using mitochondrial-specific ROS indicator MitoSOX, was significantly increased in pulmonary artery smooth muscle cells (PASMCs) from CS patients with COPD compared to normal PASMCs from non-CS patients. The increased [ROS] m was blocked by lentiviral short hairpin RNA (shRNA)-mediated knockdown of Rieske iron-sulfur protein (RISP) in mitochondrial complex III. More importantly, SMC-specific RISP gene knockout blocked nicotine/hypoxia exposure-induced PA remodeling and hypertension, whereas SMC-specific RISP overexpression exacerbated PH in mice. We further discovered that RISP regulated DNA damage following nicotine/hypoxia co-exposure via ataxia telangiectasia-mutated (ATM) signaling. RISP also mediated nuclear factor (NF)-κB inflammatory signaling. Together, our studies for the first time demonstrate that nicotine/hypoxia co-exposure leads to RISP-dependent [ROS] m , ATM-mediated DNA damage-dependent NF-κB-associated inflammation, PA vasoremodeling and PH in COPD in a sex-dependent manner. Moreover, RISP, ATM, and NF-κB may serve as novel and effective molecular targets in treating COPD and its associated PH. NIH R01 HL122865, NIH R03AG070784, and NIH R01 HL108232 This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.