Granulosa cells provide elimination of apoptotic oocytes through unconventional autophagy-assisted phagocytosis.

STUDY QUESTION: Do human granulosa cells (GCs) ingest and destroy apoptotic oocytes? SUMMARY ANSWER: Somatic GCs ingest and destroy apoptotic oocytes and other apoptotic substrates through unconventional autophagy-assisted phagocytosis. WHAT IS KNOWN ALREADY: Most (99%) ovarian germ cells undergo apoptosis through follicular atresia. The mode of cleaning of atretic follicles from the ovary is unclear. Ovarian GCs share striking similarities with testicular Sertoli cells with respect to their origin and function. Somatic Sertoli cells are responsible for the elimination of apoptotic spermatogenic cells through unconventional autophagy-assisted phagocytosis. STUDY DESIGN, SIZE, DURATION: Human GCs were tested for the ability to ingest and destroy the apoptotic oocytes and other apoptotic substrates. A systemic study of the main phagocytosis steps has been performed at different time points after loading of apoptotic substrates into the GC. PARTICIPANTS/MATERIALS, SETTING, METHODS: Primary cultures of GC retrieved following controlled ovarian stimulation of five women for IVF/ICSI and a human granulosa KGN cell line were incubated with different apoptotic substrates: oocytes which underwent spontaneous apoptosis during the cultivation of immature germ cells for IVF/ICSI; apoptotic KGN cells; and apoptotic membranes from rat retinas. Cultured GC were analyzed for the presence of specific molecular markers characteristic of different steps of phagocytic and autophagy machineries by immunocytochemistry, confocal microscopy, transmission electron microscopy and western blotting, before and after loading with apoptotic substrates. MAIN RESULTS AND THE ROLE OF CHANCE: Incubation of human GC with apoptotic substrates resulted in their translocation in cell cytoplasm, concomitant with activation of the phagocytosis receptor c-mer proto-oncogene tyrosine kinase MERTK (P < 0.001), clumping of motor molecule myosin II, recruitment of autophagy proteins: autophagy-related protein 5 (ATG5), autophagy-related protein 6 (Beclin1) and the rise of a membrane form of microtubule-associated protein 1 light chain 3 (LC3-II) protein. Ingestion of apoptotic substrates was accompanied by increased expression of the lysosomal protease Cathepsin D (P < 0.001), and a rise of lysosomes in the GCs, as assessed by different techniques. The level of autophagy adaptor, sequestosome 1/p62 (p62) protein remained unchanged. LARGE SCALE DATA: N/A. LIMITATIONS, REASONS FOR CAUTION: The number of patients described here is limited. Also the dependence of phagocytosis on reproductive hormone status of patients should be analyzed. WIDER IMPLICATIONS OF THE FINDINGS: Removal of apoptotic oocytes by surrounding GC seems likely to be a physiological mechanism involved in follicular atresia. Proper functioning of this mechanism may be a new strategy for the treatment of ovarian dysfunctions associated with an imbalance in content of germ cells in the ovaries, such as premature ovarian failure and polycystic ovary syndrome. STUDY FUNDING/COMPETING INTEREST(S): The study was funded by Rennes Metropole (AIS 2015) and Agence de BioMédecine. This work was supported by funding from Université de Rennes1, Institut National de la Santé et de la Recherche Médicale (INSERM) and CHU de Rennes. A.B. is funded in part by the program Actions Concertées Interpasteuriennes (ACIP) and a research grant from the European Society of Pediatric Endocrinology. This work is supported by the Agence Nationale de la Recherche Grants ANR-17-CE14-0038 and ANR-10-LABX-73. The authors declare no competing interests.

Update on the cellular and molecular aspects of cystic fibrosis transmembrane conductance regulator (CFTR) and male fertility.

CFTR protein regulates electrolyte and fluid transport in almost all tissues with exocrine function, including male reproductive tract. Mutation of CFTR gene causes cystic fibrosis (CF), which affects the function of several organs, and impairs male fertility. The role of CFTR protein in different compartments of male reproductive tract (testis, epididymis, sperm) as well as an impact of CFTR mutation(s) on male fertility phenotype is discussed in relation with the choice of optimal technique for Assisted Reproductive Techniques (ART) management.

Semen variation in a population of fertile donors: evaluation in a French centre over a 34-year period.

Although it has been suspected that there is a decrease in semen quality over time, the results reported to date remain debatable because of methodological issues. The aim of the study reported here was to investigate the evolution of semen quality over time in a population of 1114 fertile candidates for sperm donation at CECOS, Tours, between 1976 and 2009. We investigated semen volume, sperm concentration, progressive motility, vitality, percentage of normal forms and multiple abnormalities index of the first ejaculate in this population. We did not find a decline in semen volume, whereas we observed a significant decrease in total sperm count (from 443.2 million in 1976 to 300.2 million in 2009), motility (from 64% in 1976 to 49% in 2009) and vitality (from 88% to 80%). Moreover, a significant decline in the percentage of normal forms was noted between 1976 and 1997 (from 67% to 26%) with a steady rise in the multiple abnormalities index between 1998 and 2009 (from 1.19 to 1.65). This study involving a population of fertile men from a restricted area revealed various degrees of decline in semen parameters over a period of 34 years. These findings will have to be compared with findings in other geographical areas.

[Vitrification: Principles and results]. / La vitrification: principes et résultats.

Sperm and embryos cryopreservation is a commonly applied technique for several years. Recently authorized in France, vitrification tends to replace gradually the conventional technique of slow freezing, so upsetting the practices in the management of patients. It allows from now on the cryopreservation of oocytes and opens new perspectives in egg donation either still in fertility preservation. This review thus attempted to examine the contribution of vitrification in the freezing of oocytes and human embryos at various stages of development. If obviously vitrification appears as the current method of choice for the cryopreservation of oocytes as well as blastocysts, the results are less cut as regards embryos to early stages. No increase in adverse obstetric and perinatal outcomes in children conceived from vitrified oocytes or embryos is noted in the literature.