In vivo autophagy and biogenesis of autophagosomes within male haploid cells during spermiogenesis

// Ping Yang 1, 2 , Nisar Ahmed 1, 3 , Lingling Wang 1 , Hong Chen 1 , Yasir Waqas 1 , Tengfei Liu 1 , Abdul Haseeb 1 , Nasrullah Bangulzai 3 , Yufei Huang 1 and Qiusheng Chen 1 1 Laboratory of Animal Cell Biology and Embryology, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China 2 The Postdoctoral Research Station in Animal Science, College of Animal Science & Technology, Nanjing Agricultural University, Nanjing 210095, China 3 Department of Veterinary Anatomy & Histology, Faculty of Veterinary and Animal Sciences, LUAWMS, Uthal 90150, Pakistan Correspondence to: Qiusheng Chen, email: chenqsh305@njau.edu.cn Keywords: ATG7, LC3, male haploid cells, spermiogenesis, chrysanthemum flower center Received: March 15, 2017      Accepted: April 26, 2017      Published: May 26, 2017 ABSTRACT Autophagy is a unique catabolic pathway that is linked to several physiological processes. However, its role in the process of spermiogenesis is largely unknown. The aim of the current study was to determine the in vivo role of autophagy and the origin of autophagosome membrane biogenesis within male haploid cells. Our immunohistochemistry results demonstrated that LC3 and ATG7 localization were increased dramatically in round to elongated spermatids (haploid cells) towards the lumen of seminiferous tubules, however, poorly expressed in the early stages of germ cells near the basal membrane. Moreover, transmission electron microscopy revealed that the numbers of lysosomes and autophagosomes increased in the elongated spermatids as spermiogenesis progressed. However, no evidence was found for the presence of autophagosomes in the Sertoli cells, spermatogonia or early primary spermatocytes (diploid cells). Furthermore, TEM showed that many endoplasmic reticula were transformed into a “chrysanthemum flower center,” from which a double-layered isolation membrane appeared to develop into an autophagosome. This study provides novel evidence about the formation of autophagosomes through the chrysanthemum flower center from the endoplasmic reticulum, and suggests that autophagy may have an important role in the removal of extra cytoplasm within male haploid cells during spermiogenesis.