ZLN005 improves the protective effect of mitochondrial function on alveolar epithelial cell aging by upregulating PGC-1α

Miao Ma; Yujuan Gao; Xiaohua Qiu; Xianhua Gui; Yaqiong Tian; Mi Tian; Timothy E Albertson; Tomoo Kishaba; Yoshinori Tanino; Yuichi Sakairi; Jingyu Chen; Jinghong Dai; Hourong Cai

doi:10.21037/jtd-23-815

ZLN005 improves the protective effect of mitochondrial function on alveolar epithelial cell aging by upregulating PGC-1α

J Thorac Dis. 2023 Nov 30;15(11):6160-6177. doi: 10.21037/jtd-23-815. Epub 2023 Nov 27.

Authors

Miao Ma^#^{1

2}, Yujuan Gao^#², Xiaohua Qiu^#², Xianhua Gui², Yaqiong Tian², Mi Tian², Timothy E Albertson³, Tomoo Kishaba⁴, Yoshinori Tanino⁵, Yuichi Sakairi⁶, Jingyu Chen⁷, Jinghong Dai², Hourong Cai^{1

2}

Affiliations

¹ Department of Respiratory and Critical Care Medicine, Nanjing Drum Tower Hospital Clinical College of Nanjing Medical University, Nanjing, China.
² Department of Respiratory and Critical Care Medicine, Nanjing Drum Tower Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing, China.
³ Department of Internal Medicine, Division of Pulmonary, Critical Care and Sleep Medicine, University of California, Davis, Sacramento, CA, USA.
⁴ Department of Respiratory Medicine, Okinawa Chubu Hospital, Okinawa, Japan.
⁵ Department of Pulmonary Medicine, Fukushima Medical University School of Medicine, Fukushima, Japan.
⁶ Department of General Thoracic Surgery, Chiba University Graduate School of Medicine, Chiba, Japan.
⁷ Jiangsu Key Laboratory of Organ Transplantation, Wuxi People's Hospital, Nanjing Medical University, Wuxi, China.

^# Contributed equally.

Abstract

Background: Idiopathic pulmonary fibrosis (IPF) is a chronic and fatal pulmonary interstitial disease that usually occurs in the elderly. The senescence of alveolar epithelial cells (AECs) is an important mechanism of IPF. The AECs of patients with IPF have lower expression of peroxisome proliferator-activated receptor-γ coactivator-1 alpha (PGC-1α), which has been shown to play an important role in maintaining mitochondrial morphology and energy metabolism. This study sought to explore the mechanism by which ZLN005 improves mitochondrial function by upregulating PGC-1α to protect AECs from aging.

Methods: Western blot was used to detect the expression of PGC-1α, mitochondrial synthesis protein nuclear respiratory factor-1 (NRF-1), and p21^WAF1 in the lung tissue of the IPF patients and the mice with bleomycin (BLM)-induced pulmonary fibrosis. A549 cells and mice AEC2 cells were treated with hydrogen peroxide (H₂O₂) to construct cell senescence models. Cell senescence was detected by senescence-associated beta-galactosidase staining. The mitochondrial respiratory function was measured, including the adenosine triphosphate (ATP) generation, reactive oxygen species (ROS) level, changes in cell membrane potential, and energy metabolism. Using lentivirus as a vector and using gene editing technology to over express (upPGC-1α) and knockdown PGC-1α (shPGC-1α) in the A549 cells. The PGC-1α agonist ZLN005 was used to pretreat the A549 and shPGC-1α A549 cells, and cell aging and mitochondrial respiratory function were observed.

Results: The Western blot and immunofluorescence assays showed that the expression of PGC-1α and NRF-1 was decreased in the lung tissues of the IPF patients and BLM-induced mice pulmonary fibrosis model, while the expression of p21^WAF1 was increased. The results of the immunofluorescence and mitochondrial function experiments also indicated that the expression of PGC-1α and mitochondrial synthesis protein NRF-1 were decreased in the senescent cells. Further, the mitochondrial morphology was abnormal and the mitochondrial function was impaired. PGC-1α was involved in the AEC senescence by regulating mitochondrial morphology and function. Treatment with the agonist of PGC-1α (i.e., ZLN005) blocked the H₂O₂-induced cell senescence by enhancing the expression of PGC-1α.

Conclusions: These results provide preliminary insights into the potential clinical application of ZLN005 as a novel therapeutic agent for the treatment of IPF.

Keywords: Idiopathic pulmonary fibrosis (IPF); alveolar epithelial cells (AECs); cellular senescence; mitochondrial function; peroxisome proliferator-activated receptor-γ coactivator-1 alpha (PGC-1α).