Spermidine induces cytoprotective autophagy of female germline stem cells in vitro and ameliorates aging caused by oxidative stress through upregulated sequestosome-1/p62 expression

Xiaoyan Yuan,Xiaopeng Hu,Geng G Tian,Xiuying Pei,Ji Wu

doi:10.1186/s13578-021-00614-4

Abstract

BackgroundAutophagy is required for oogenesis and plays a critical role in response to aging caused by oxidative stress. However, there have been no reports on regulation of cytoprotective autophagy in female germline stem cells (FGSCs) in response to aging caused by oxidative stress.ResultsWe found that Spermidine (SPD) significantly increased protein expression of autophagy markers microtubule-associated protein 1 light chain 3 beta-II (MAP1LC3B-II/LC3B-II) and sequestosome-1/p62 (SQSTM1/p62), and evoked autophagic flux in FGSCs. Moreover, SPD increased the number and viability of FGSCs in vitro. Further, we found that SPD significantly reduced basal or hydrogen peroxide (H2O2)-induced up-regulated protein expression of the aging markers, cyclin dependent kinase inhibitor 2A (p16/CDKN2A) and tumor protein 53 (p53). After knockdown of p62 in FGSCs, p16 protein levels were significant higher compared with controls. However, protein p16 levels were not significantly changed in p62 knockdown FGSCs with SPD treatment compared with without SPD. Moreover, SPD significantly changed the expression of autophagy-related genes and pathways in FGSCs, as shown by bioinformatics analysis of RNA sequencing data. Additionally, SPD significantly inhibited AKT/mTOR phosphorylation.ConclusionsSPD induces cytoprotective autophagy in FGSCs in vitro and ameliorates cellular senescence of FGSCs induced by H2O2. Furthermore, SPD can ameliorate cellular senescence of FGSCs through p62. SPD might induce autophagy in FGSCs via the PI3K/Akt pathway. Our findings could be helpful for delaying aging of female germ cells due to oxidative stress and preserving female fertility.

Highlights

Hyper-activation of autophagy is believed to cause autophagy-dependent cell death, autophagy primarily protects against cellular insults, nutrient starvation, or oxidative stress
There have been no reports on regulation of cytoprotective autophagy in female germline stem cells (FGSCs) in response to aging caused by oxidative stress
We found that 100 μM SPD significantly increased LC3B-II protein expression in a time-dependent manner from 4 to 16 h (Fig. 1A)

Summary

Introduction

Hyper-activation of autophagy is believed to cause autophagy-dependent cell death, autophagy primarily protects against cellular insults, nutrient starvation, or oxidative stress. Yuan et al Cell Biosci (2021) 11:107 organelles and harmful protein aggregates. This process removes and recycles cytoplasmic material that otherwise would accumulate during aging [1]. Cytoprotective autophagy is essential for cellular homeostasis [3], while a decline in activity of autophagy is a central molecular mechanism leading to aging [4, 5]. Autophagy is required for oogenesis and plays a critical role in response to aging caused by oxidative stress. There have been no reports on regulation of cytoprotective autophagy in female germline stem cells (FGSCs) in response to aging caused by oxidative stress

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