Reproductive MedicineCell BiologyObstetrics and GynecologyEmbryologyEndocrinology
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Reproduction is the official journal of the Society of Reproduction and Fertility (SRF). It was formed in 2001 when the Society merged its two journals, the Journal of Reproduction and Fertility and Reviews of Reproduction. Reproduction publishes original research articles and topical reviews on the subject of reproductive and developmental biology, and reproductive medicine. The journal will consider publication of high-quality meta-analyses; these should be submitted to the research papers category. The journal considers studies in humans and all animal species, and will publish clinical studies if they advance our understanding of the underlying causes and/or mechanisms of disease. Scientific excellence and broad interest to our readership are the most important criteria during the peer review process. The journal publishes articles that make a clear advance in the field, whether of mechanistic, descriptive or technical focus. Articles that substantiate new or controversial reports are welcomed if they are noteworthy and advance the field. Topics include, but are not limited to, reproductive immunology, reproductive toxicology, stem cells, environmental effects on reproductive potential and health (eg obesity), extracellular vesicles, fertility preservation and epigenetic effects on reproductive and developmental processes.
The intricate molecular and cellular interactions between spermatogonial stem cells (SSCs) and their cognate niche form the basis for life-long sperm production. To maintain long-term fertility and sustain sufficiently high levels of spermatogenesis, a delicate balance needs to prevail between the different niche factors that control cell fate decisions of SSCs by promoting self-renewal, differentiation priming or spermatogenic commitment of undifferentiated spermatogonia (Aundiff). Previously the SSC niche was thought to be formed primarily by Sertoli cells. However, recent research has indicated that many distinct cell types within the testis contribute to the SSC niche including most somatic cell populations and differentiating germ cells. Moreover, postnatal testis development involves maturation of somatic supporting cell populations and onset of cyclic function of the seminiferous epithelium. The stochastic and flexible behavior of Aundiff further complicates the definition of the SSC niche. Unlike in invertebrate species, providing a simple anatomical description of the SSC niche in the mouse is therefore challenging. Rather, the niche needs to be understood as a dynamic system that is able to serve the long-term reproductive function and maintenance of fertility both under steady-state and during development plus regeneration. Recent data from us and others have also shown that Aundiff reversibly transition between differentiation-primed and self-renewing states based on availability of niche-derived cues. This review focuses on defining the current understanding of the SSC niche and the elements involved in its regulation.
Philippa Saunders, Justine Turner, Matteo Ruggiu, Mary Taggart, Paul S. Burgoyne, David J. Elliott, Howard J. Cooke
The autosomal gene DAZL is a member of a family of genes (DAZL, DAZ, BOULE), all of which contain a consensus RNA binding domain and are expressed in germ cells. Adult male and female mice null for Dazl lack gametes. In order to define more precisely the developmental stages in germ cells that require Dazl expression, the patterns of germ cell loss in immature male and female wild-type (+/+, WT) and Dazl -/- (DazlKO) mice were analysed. In females, loss of germ cells occurred during fetal life and was coincident with progression of cells through meiotic prophase. In males, testes were recovered from WT and DazlKO males obtained before and during the first wave of spermatogenesis (days 2-19). Mitotically active germ cells were present up to and including day 19. Functional differentiation of spermatogonia associated with detection of c-kit positive cells did not depend upon expression of Dazl. RBMY-positive cells (A, intermediate, B spermatogonia, zygotene and preleptotene spermatocytes) were reduced in DazlKO compared with WT testes. Staining of cell squashes from day 19 testes with anti-gamma-H2AX and anti-SCP3 antibodies showed that germ cells from DazlKO males were unable to progress beyond the leptotene stage of meiotic prophase I. It was concluded that in the absence of Dazl, germ cells can complete mitosis, and embark on functional differentiation but that, in both sexes, progression through meiotic prophase requires this RNA binding protein.
Maria Elena Manca, Maria Lucia Manunta, Antonio Spezzigu, Laura Torres-Rovira, Antonio González-Bulnes, Valeria Pasciu, Peter Piu, Giovanni Giuseppe Leoni, Sara Succu, Didier Chesneau, Salvatore Naitana, Fiammetta Berlinguer
This study assessed the effect of melatonin deprival on ovarian status and function in sheep. Experimental procedures were carried out within two consecutive breeding seasons. Animals were divided into two groups: pinealectomised (n=6) and sham-operated (n=6). The completeness of the pineal gland removal was confirmed by the plasma concentration of melatonin. Ovarian status was monitored by ovarian ultrasonography for 1 year to study reproductive seasonality. Follicular and corpus luteal growth dynamics were assessed during an induced oestrous cycle. As the effects of melatonin on the ovary may also be mediated by its antioxidant properties, plasma Trolox equivalent antioxidant capacity (TEAC) was determined monthly for 1 year. Pinealectomy significantly extended the breeding season (310±24.7 vs 217.5±24.7 days in controls;P<0.05). Both pinealectomised and sham-operated ewes showed a well-defined wave-like pattern of follicle dynamics; however, melatonin deficiency caused fewer waves during the oestrous cycle (4.3±0.2 vs 5.2±0.2;P<0.05), because waves were 1 day longer when compared with the controls (7.2±0.3 vs 6.1±0.3;P<0.05). The mean area of the corpora lutea (105.4±5.9 vs 65.4±5.9 mm2;P<0.05) and plasma progesterone levels (7.1±0.7 vs 4.9±0.6 ng/ml;P<0.05) were significantly higher in sham-operated ewes compared with pinealectomised ewes. In addition, TEAC values were significantly lower in pinealectomised ewes compared with control ones. These data suggest that melatonin, besides exerting its well-known role in the synchronisation of seasonal reproductive fluctuations, influences the growth pattern of the follicles and the steroidogenic capacity of the corpus luteum.Free Italian abstractAn Italian translation of this abstract is freely available athttp://www.reproduction-online.org/content/147/6/885/suppl/DC1.
CE Green, J. C. S. Bredl, W. V. Holt, P.P. Watson, Alireza Fazeli
After mating, mammalian spermatozoa are transported to the lower oviductal isthmus. Spermatozoa are sequestered at the isthmus by attaching and interacting with oviductal epithelial cells, hence forming a sperm reservoir. In several mammalian species, specific carbohydrates mediate sperm-oviductal epithelial cell binding. A quantitative in vitro free cell bioassay was developed to investigate the involvement of carbohydrate recognition in pig sperm-oviductal epithelial cell interactions. This assay was validated. The sensitivity of the assay was such that it was possible to discriminate between different sperm concentrations and sperm-oviductal epithelial cell co-incubation periods, spermatozoa with damaged plasma membranes and epithelial cells of non-reproductive origin. Optimal conditions were used to incubate spermatozoa and oviductal epithelial cells in the presence of six hexose sugars at concentrations of 0, 2, 10 and 50 mmol l(-1). A significant (P < or = 0.05) reduction in the binding of spermatozoa to the oviductal epithelium was detected with 2, 10 and 50 mmol maltose l(-1), 50 mmol lactose l(-1) and 50 mmol mannose l(-1). These findings support the hypothesis that attachment of pig spermatozoa to oviductal epithelium before fertilization is mediated by carbohydrate recognition.