miR-15b induces premature ovarian failure in mice via inhibition of α-Klotho expression in ovarian granulosa cells

Free Radic Biol Med. 2019 Sep:141:383-392. doi: 10.1016/j.freeradbiomed.2019.07.010. Epub 2019 Jul 13.

Abstract

A thorough understanding of epigenetics regulatory mechanisms of premature ovarian failure (POF) is still lacking. Here, we found that cyclophosphamide induced significantly decrease in α-Klotho (Kl) expression in mouse ovarian granulosa cells (mOGCs), suggesting that cyclophosphamide inhibited Kl expression. Cyclophosphamide also significantly accelerated ageing and led to a decline in the pregnancy rate of C. elegans. We subsequently noted that the pathological condition exhibited by Kl-/- mice was similar to that observed in cyclophosphamide-induced POF mice. Furthermore, the mOGCs in both types of mice showed significant signs of oxidative stress damage, including decreased SOD and ATP, increased ROS levels. Detailed analyses revealed that the decreased Kl expression led to the reduced expression of autophagy-related proteins in mOGCs, which resulted in decreased autophagy activity. Finally, we found that cyclophosphamide attenuated the autophagy function of mOGCs via upregulating microRNA-15b expression, which silenced the endogenous Kl mRNA expression and stimulated the activity of the downstream TGFβ1/Smad pathway. Therefore, we demonstrated that Kl was one of the key inhibitory factors in the development of POF. It elucidated the underlying epigenetic regulatory mechanism, whereby cyclophosphamide-dependent microRNA-15b inhibited Kl expression, leading to the reduced ability of mOGCs to induce autophagy and ROS scavenging, ultimately causing POF.

Keywords: Autophagy; Ovarian granulosa cells; Oxidative stress; Premature ovarian failure; microRNA; α-Klotho.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Autophagy / drug effects
  • Cyclophosphamide / pharmacology
  • Female
  • Gene Expression Regulation / drug effects
  • Glucuronidase / genetics*
  • Granulosa Cells / metabolism*
  • Granulosa Cells / pathology
  • Humans
  • Klotho Proteins
  • Mice
  • MicroRNAs / genetics*
  • Ovarian Follicle / metabolism
  • Ovarian Follicle / pathology
  • Pregnancy
  • Primary Ovarian Insufficiency / drug therapy
  • Primary Ovarian Insufficiency / genetics*
  • Primary Ovarian Insufficiency / pathology
  • Signal Transduction / drug effects
  • Smad Proteins / genetics
  • Transforming Growth Factor beta1 / genetics

Substances

  • MicroRNAs
  • Mirn15 microRNA, mouse
  • Smad Proteins
  • Tgfb1 protein, mouse
  • Transforming Growth Factor beta1
  • Cyclophosphamide
  • Glucuronidase
  • Klotho Proteins