Ambient fine particulate matter disrupts hepatic circadian oscillation and lipid metabolism in a mouse model

Ran Li; Yixuan Wang; Rucheng Chen; Weijia Gu; Lu Zhang; Jinge Gu; Ziyao Wang; Ying Liu; Qinghua Sun; Kezhong Zhang; Cuiqing Liu

doi:10.1016/j.envpol.2020.114179

Ambient fine particulate matter disrupts hepatic circadian oscillation and lipid metabolism in a mouse model

Environ Pollut. 2020 Jul:262:114179. doi: 10.1016/j.envpol.2020.114179. Epub 2020 Feb 28.

Authors

Ran Li¹, Yixuan Wang¹, Rucheng Chen¹, Weijia Gu¹, Lu Zhang¹, Jinge Gu², Ziyao Wang³, Ying Liu³, Qinghua Sun⁴, Kezhong Zhang⁵, Cuiqing Liu⁶

Affiliations

¹ School of Basic Medical Sciences and Public Health, Joint China-US Research Center for Environment and Pulmonary Diseases, Zhejiang Chinese Medical University, Hangzhou 310053, China.
² CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, CAS Center for Excellence in Nanoscience, Beijing Key Laboratory of Ambient Particles Health Effects and Prevention Techniques, National Center for Nanoscience and Technology of China and University of Chinese Academy of Sciences, Beijing 100190, China; Key Laboratory of Medicinal Chemistry and Molecular Diagnosis of Ministry of Education, College of Chemistry and Environmental Science, Hebei University, Baoding, China.
³ CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, CAS Center for Excellence in Nanoscience, Beijing Key Laboratory of Ambient Particles Health Effects and Prevention Techniques, National Center for Nanoscience and Technology of China and University of Chinese Academy of Sciences, Beijing 100190, China.
⁴ College of Public Health, The Ohio State University, Columbus, OH, USA.
⁵ Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, MI, USA.
⁶ School of Basic Medical Sciences and Public Health, Joint China-US Research Center for Environment and Pulmonary Diseases, Zhejiang Chinese Medical University, Hangzhou 310053, China. Electronic address: liucuiqing@zcmu.edu.cn.

PMID: 32145476
DOI: 10.1016/j.envpol.2020.114179

Abstract

Emerging evidence has shown that exposure to ambient fine particulate matter (PM_2.5) is associated with hepatic lipid accumulation. However, the underlying mechanism is not fully characterized yet. Autonomous circadian clock in the liver plays a fundamental role in maintaining lipid metabolism homeostasis. In this study, we evaluated the effects of ambient PM_2.5 exposure on the expression of hepatic circadian clock genes and expression rhythm of genes associated with lipid metabolism in mice liver. Male C57BL/6 mice were randomly assigned to ambient PM_2.5 or filtered air for 10 weeks via a whole body exposure system. We found that the liver mass was reduced significantly at zeitgeber time (ZT) 8 in mice exposed to PM_2.5 but not levels or circadian rhythm of hepatic triglycerides or free fatty acid (FFA). In addition, exposure to PM_2.5 led to enhanced expression of bmal1 at ZT0/24, cry1 at ZT16 and rev-erbα at ZT4 and ZT8. Furthermore, the expression of pparα was enhanced in mice liver at ZT4 and ZT8 after PM_2.5 exposure, with upregulation of pparα-mediated genes responsible for fatty acid transport and oxidation. Finally, the expression of rate-limiting enzymes for lipid synthesis was all significantly increased in the liver of PM_2.5 exposed mice at ZT12. Therefore, the present study provides new perspectives for revealing the etiology of hepatic lipid metabolism abnormality from PM_2.5-induced circadian rhythm disorder.

Keywords: Air pollution; Ambient fine particulate matter; Circadian rhythm; Lipid metabolism; Liver.

MeSH terms

Animals
Circadian Clocks*
Circadian Rhythm
Lipid Metabolism
Liver
Male
Mice
Mice, Inbred C57BL
Particulate Matter*

Substances

Particulate Matter