Nanos2 is a molecular marker of inchoate buffalo spermatogonia

Additional glial cell line-derived neurotrophic factor in vitro promotes the proliferation of undifferentiated spermatogonia from sterile cattleyak

Cattleyak is a typically male sterile species. The meiosis process is blocked and the scarcity of spermatogenic stems cells are both contributing factors to the inability of male cattleyak to produce sperm. While Glial cell line-derived neurotrophic factor (GDNF) is the first discovered growth factor known to promote the proliferation and self-renewal of spermatogenic stem cells, its relationship to the spermatogenesis arrest of cattleyak remains unclear. In this report, we studied the differential expression of GDNF in the testis of yak and cattleyak, and discussed the optimal concentration of GDNF in the culture medium of undifferentiated spermatogonia (UDSPG) of cattleyak in vitro and the effect of GDNF on the proliferation of cattleyak UDSPG. The results indicated that GDNF expression in the testicular tissue of cattleyak was inferior to that of yak. Moreover, the optimum value for the UDSPG in vitro culture was determined to be 20-30 ng/mL for cattleyak. In vitro, the proliferation activity of UDSPG was observed to increase with additional GDNF due to the up-regulation of proliferation-related genes and the down-regulation of differentiation-related genes. We hereby report that the scarcity of cattleyak UDSPG is due to insufficient expression of GDNF, and that the addition of GDNF in vitro can promote the proliferation of cattleyak UDSPG by regulating the expression of genes related to proliferation and differentiation. This work provides a new insight to solve the issue of spermatogenic arrest in cattleyak.

Comparison of the effects of buffalo LIF and mouse LIF on the in vitro culture of buffalo spermatogonia

Leukemia inhibitory factor (LIF) is an important growth factor that supports the culture and maintenance of spermatogonial stem cells (SSCs) by suppressing spontaneous differentiation. Different LIF sequences may lead to differences in function. The protein sequences of buffalo LIF and mouse LIF differed by 65.5% according to MEGA software analysis. The PB-LIF-GFP-Puro vector was constructed, and the CHO-K1 cell line was established. The final LIF protein concentration in the CHO-K1 cell culture medium was approximately 4.268 ng/mL. Here, we report that buffalo LIF effectively maintains the self-renewal of buffalo spermatogonia during culture. Buffalo spermatogonia were cultured in conditioned medium containing no LIF (0 ng/mL), mouse LIF (1 ng/mL), mouse LIF (10 ng/mL), or buffalo LIF (1 ng/mL). Furthermore, the effects of mouse LIF and buffalo LIF culture on the maintenance of buffalo spermatogonia were determined by analyzing cell colony formation, quantitative real-time polymerase chain reaction, cell immunofluorescence, and cell counting. The buffalo LIF (1 ng/mL) group showed similar maintenance of the proliferation of buffalo spermatogonia to that in the mouse LIF (10 ng/mL) group. These results demonstrated that the proliferation of buffalo spermatogonia can be maintained in vitro by adding a low dose of buffalo LIF. This study provides a foundation for the further optimization of in vitro buffalo SSC culture systems.

Molecular Cloning and Sexually Dimorphic Expression Analysis of nanos2 in the Sea Urchin, Mesocentrotus nudus

Sea urchin (Mesocentrotus nudus) is an economically important mariculture species in China and the gonads are the solely edible parts to human. The molecular mechanisms of gonad development have attracted increasing attention in recent years. Although the nanos2 gene has been identified as a germ cell marker in several invertebrates, little is known about nanos2 in adult sea urchins. Hereinto, we report the characterization of Mnnano2, an M. nudus nanos2 homology gene. Mnnanos2 is a maternal factor and can be detected continuously during embryogenesis and early ontogeny. Real-time quantitative PCR (RT-qPCR) and section in situ hybridization (ISH) analysis revealed a dynamic and sexually dimorphic expression pattern of Mnnano2 in the gonads. Its expression reached the maximal level at Stage 2 along with the gonad development in both ovary and testis. In the ovary, Mnnanos2 is specifically expressed in germ cells. In contrast, Mnnanos2 is expressed in both nutritive phagocytes (NP) cells and male germ cells in testis. Moreover, knocking down of Mnnanos2 by means of RNA interference (RNAi) reduced nanos2 and boule expression but conversely increased the expression of foxl2. Therefore, our data suggest that Mnnanos2 may serve as a female germ cell marker during gametogenesis and provide chances to uncover its function in adult sea urchin.

Spermatogonial stem cells identified by molecular expression of PLZF, integrin β1 and reactivity to Dolichos biflorus agglutinin in alpaca adult testes

The identification system of spermatogonial stem cell (SSC) was established in alpaca using the molecular expression as well as the reactivity pattern to Dolichos biflorus agglutinin (DBA) by flow cytometry. Twenty-four testicles with their epididymis were recovered from adult alpacas at the slaughterhouse of Huancavelica-Perú. Samples were transported to the Laboratory of Reproductive Physiology at Universidad Nacional Mayor de San Marcos. Testes were selected for our study when the progressive motility of epididymal spermatozoa (ESPM) was above 30%. Isolation of SSC was performed with two enzymatic digestions. Finally, sperm viability was evaluated by means of the trypan blue vital stain in spermatogonial round cells. Samples with more than 80% viability were selected. Isolated cells cultured for 2 days were used for identifying the presence of SSCs by the expression of integrin β1 (116 bp) and PLZF (206 bp) genes. Spermatogonia were classified according to the DBA reactivity. Spermatogonia with a strong positive to DBA (sDBA⁺ ) were classified as SSC (Mean ± SEM=4.44 ± 0.68%). Spermatogonia in early differentiation stages stained weakly positive with DBA (wDBA⁺ ) (Mean ± SEM=37.44 ± 3.07%) and differentiated round cells as DBA negative (Mean ± SEM=54.12 ± 3.18%). With the use of molecular and DBA markers, it is possible to identify easily the spermatogonial stem cells in alpaca.