Epigenetics, spermatogenesis, and male infertility

Abstract

Spermatogenesis is a complicated process comprising three main stages, namely, the proliferation (mitotic proliferation of spermatogonia), maturation (meiotic division and development of germ cells into spermatocytes), and differentiation (spermiogenesis). This process is starting with diploid stem cells, the spermatogonia, and ending with the release of haploid mature spermatozoa. This process needs timely and fast transitions between mitotic, meiotic, and postmeiotic stages, which are closely organized at both transcriptional and posttranscriptional levels. Recent data indicate that epigenetic regulation plays an essential role in the control of gene expression regulating transitions between the main phases of spermatogenesis in mammals. Epigenetic regulation could be affected by a variety of environmental factors, and their aberrations including DNA methylation of developmental and imprinted genes, modifications of histones, packaging of sperm DNA with protamines, and miRNAs have been implicated in various human diseases. This chapter highlights the current findings on the impacts of epigenetic modifications on male infertility. © 2018 Elsevier Inc. All rights reserved.