Effect of cigarette smoke extract on mitochondrial division in mouse quadriceps femoris cells

Zhidan Tan; Siqi Li; Su Zhu; Xiaoxuan Yao; Jing Li; Xinglin Gao; Shifang Yang

doi:10.21037/atm-21-5891

Effect of cigarette smoke extract on mitochondrial division in mouse quadriceps femoris cells

Ann Transl Med. 2021 Nov;9(22):1699. doi: 10.21037/atm-21-5891.

Authors

Zhidan Tan¹, Siqi Li¹, Su Zhu², Xiaoxuan Yao², Jing Li³, Xinglin Gao^#³, Shifang Yang^#³

Affiliations

¹ The Second School of Clinical Medicine, Southern Medical University, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China.
² Shantou University Medical College, Shantou, China.
³ Department of Respiratory and Critical Care Medicine, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangdong Provincial Geriatrics Institute, The Second School of Clinical Medicine, Southern Medical University, Guangzhou, China.

^# Contributed equally.

Abstract

Background: To observe the effect of cigarette smoke extract (CSE) on mitochondrial division in mouse quadriceps femoris cells and to explore the potential molecular mechanism of skeletal muscle dysfunction (SMD) in patients with chronic obstructive pulmonary disease (COPD).

Methods: Quadriceps femoris were cultured, passaged, and stimulated with different concentrations of CSE. We divided cells into four groups (Control, 2.5%, 5%, 10%). The growth of cells, the expression of Dynamin related protein 1 (Drp-1), and apoptosis were observed and evaluated by fluorescence microscopy, RT-PCR, Western blot, and flow cytometry.

Results: The longer the intervention time, the more obvious the decrease in cell number. In the 5% and 10% groups, the cells became round with gaps. Under an inverted fluorescence microscope, the green fluorescence of cells in 5% and 10% stained with Mito-Tracker Green was significantly less than that of the Control and 2.5%. Red fluorescence was reduced and the green fluorescence was increased in the 5% and 10% stained with JC-1. Flow cytometry analysis showed that reactive oxygen species (ROS) and apoptosis were increased in the CSE intervention groups. In the Control, 2.5%, 5%, and 10%, the levels of ROS were 0.052±0.015, 0.170±0.030, 5.340±0.500, and 24.400±1.900, respectively. The apoptotic rates (%) were 0.270±0.009, 2.650±0.060, 11.850±0.020, and 31.820±1.260, respectively. The relative expression levels were, 0.900±0.093, 1.141±0.099, 1.361±0.034, 2.155±0.092 for DNM1L mRNA, and 0.509±0.008, 0.569±0.028, 0.792±0.048, 0.940±0.062 for Drp-1. There were significant differences in the apoptotic rate, and Drp-1 expression between 5% and 10% compared with the Control and 2.5% (P<0.05).

Conclusions: CSE may enhance mitochondrial division of quadriceps femoris cells by up-regulating the expression of Drp-1, affecting cellular energy metabolism and promoting quadriceps femoris apoptosis, ultimately leading to the occurrence and development of skeletal muscle dysfunction in COPD.

Keywords: Chronic obstructive pulmonary disease (COPD); Dynamin related protein 1 (Drp-1); cigarette smoke extract (CSE); quadriceps femoris.