Endogenous leptin promotes autophagy in EBSS-induced PFCs

Deling Jiao,Zhen Yang,Lulu Wang,Binyue Hu,Jing Wang,Anyong Xu,Wenmin Cheng,Baoyu Jia,Yubo Qing,Hong-Ye Zhao,Hong-Jiang Wei

doi:10.1080/19768354.2019.1651766

Abstract

ABSTRACTLeptin is an important adipokine and plays a vital role in animals. However, the role of leptin in the autophagic response of pig fibroblast cells (PFCs) has not been fully elucidated. In this study, we investigated the relationship between leptin and autophagy as well as underlying molecular basis. We found that PFCs treated with EBSS could secrete leptin, and the leptin concentration in the supernatant of leptin transgenic PFCs was higher than that of WT PFCs. We found an increase in LC3-II protein level and a decrease in p62 protein level in treated leptin transgenic PFCs compared with treated WT PFCs. Meanwhile, we observed an increase of autophagosomes by transmission electron microscopy and an enhancement of the accumulation of LC3 puncta in the cytoplasm of treated leptin transgenic PFCs, and these effects were further augmented by Baf A1 treatment. Furthermore, we detected the expression levels of 7 autophagy signaling pathway genes and 17 autophagy-related (ATG) genes by q-PCR. We found that between the two types of EBSS-treated cells 3 genes expression pattern were significantly different among the 7 autophagy signaling pathway genes and 8 genes expression pattern were significantly differernt among the ATG genes. These results indicated that leptin may promote autophagy and involving the downregulation of FOXO1 and LMNA genes via an unknown pathway which causes the upregulation of the 4 genes and the downregulation of 4 genes.

Highlights

Leptin is a polypeptide hormone secreted mainly by animal adipocytes and encoded by the OB gene (Matarese et al 2010)
The ELISA results showed that the leptin concentration was significantly increased in leptin transgenic pig fibroblast cells (PFCs) compared with WT PFCs (Figure 1(A))
We found that the expression level of P62 decreased and the expression level of LC3-II increased after EBSS treatment at 4 h in leptin transgenic PFCs, while the expression of LC3-II and P62 was not changed in WT PFCs

Summary

Introduction

Leptin is a polypeptide hormone secreted mainly by animal adipocytes and encoded by the OB gene (Matarese et al 2010). Leptin is involved in signaling pathways regulating cell proliferation, differentiation and survival (Villanueva and Myers 2008), autophagy (Cassano et al 2014) and nutrient metabolism (Varela and Horvath 2012). Autophagy is a cellular metabolic process that maintains physiological function and homeostasis through liposomal protein degradation. Autophagy plays an important role in the growth and development of animals, cell differentiation and the occurrence and development of diseases (Gozuacik and Kimchi 2004). Abnormal autophagy can lead to many diseases, such as energy metabolis (Jacob et al 2017) and immune-related diseases (Deretic et al 2013)

Methods

Results

Conclusion