Search

Undifferentiated germ cells, including spermatogonial stem cells (SSCs), make up only a very small proportion of germ cells within the testis; for example, 0.03% of germ cells in the mouse testis are SSCs. In this study, we investigated the characteristics of bovine undifferentiated germ cells and developed an enrichment procedure for these cells on the basis of fluorescence-activated cell sorting (FACS), using the specific cell surface marker glial cell line-derived neurotrophic factor family receptor alpha 1 (GFRα1). FACS analysis showed that only 0.6% of the total testicular cells were GFRα1-positive. These GFRα1-positive cells had a significantly higher expression of UCHL1, ZBTB16, and DDX4 (all markers of undifferentiated spermatogonial and germ cells) than that of fresh testicular cells. Quantitative reverse-transcription PCR analyses also indicated that the gene expression of BCL6B and NANOS2 was significantly higher in GFRα1-positive cells. Furthermore, xenogeneic transplantation of bovine testicular cells into immunodeficient mice resulted in 4.4-fold more colonies of GFRα1-positive cells than those of fresh testicular cells, indicating that FACS with antibodies to GFRα1 had efficiently enriched putative SSCs from total testicular cells. Collectively, these results demonstrate that GFRα1 could be used as a marker of bovine undifferentiated germ cells, including putative SSCs, and that its expression on SSCs has important implications for the further development of techniques for enriching stem cells from other species. • FACS selection with GFRα1 facilitates enrichment for undifferentiated spermatogonia. • GFRα1-positive cell population is enriched in putative SSCs. • Expression of GFRα1 is conserved among bovine and other species. [ABSTRACT FROM AUTHOR]

Purpose: To investigate if T. officinale root aqueous extract has anti-spermatogenic activity similar to that of the whole plant which was shown previously to inhibit spermatogenesis. Methods: T. officinale aqueous extract was prepared by soaking 100 g of dried materials in 1 L distilled water for two days at 45 °C. Fifty adult male rats were divided into five groups and treated for 60 days. Four groups were gavaged with the whole plant or root aqueous extract in low or high doses. The male rat rats were allowed to mate with female rats. The control group received distilled water. Sperm count, motility and morphology as well as chromatin integrity were evaluated. Results: Serum testosterone level, sperm parameters, pregnancy rate and average number of fetuses per pregnant females decreased significantly in the treated groups compared to control and in the rootreceiving rats compared to the whole plant-receiving rats. Female rats which were mated with high dose root-receiving males did not deliver fetuses. Cross sections of seminiferous tubules of T. officinaletreated rats showed lesions and disorganized germinal epithelium. Late spermatogenesis maturation arrest (spermatid stage) was observed in all of the treated groups except the high dose root-receiving group which showed early maturation arrest (spermatocyte stage). In addition, the mRNA level of two spermatogonial stem cell markers responsible for self-renewal and proliferation of spermatogonia increased in high dose-receiving rats. Conclusion: T. officinale root aqueous extract has inhibitory effects on spermatogenesis. Further studies are required to identify specific ingredient(s) in T. officinale that may be useful as male contraceptive(s). [ABSTRACT FROM AUTHOR]

In a healthy adult brain, glial cell line-derived neurotrophic factor (GDNF) is exclusively expressed by neurons, and, in some instances, it has also been shown to derive from a single neuronal subpopulation. Secreted GDNF acts in a paracrine fashion by forming a complex with the GDNF family receptor α1 (GFRα1), which is mainly expressed by neurons and can act in cis as a membrane-bound factor or in trans as a soluble factor. The GDNF/GFRα1 complex signals through interactions with the "rearranged during transfection" (RET) receptor or via the neural cell adhesion molecule (NCAM) with a lower affinity. GDNF can also signal independently from GFRα1 by interacting with syndecan-3. RET, which is expressed by neurons involved in several pathways (nigro–striatal dopaminergic neurons, motor neurons, enteric neurons, sensory neurons, etc.), could be the main determinant of the specificity of GDNF's pro-survival effect. In an injured brain, de novo expression of GDNF occurs in glial cells. Neuroinflammation has been reported to induce GDNF expression in activated astrocytes and microglia, infiltrating macrophages, nestin-positive reactive astrocytes, and neuron/glia (NG2) positive microglia-like cells. This disease-related GDNF overexpression can be either beneficial or detrimental depending on the localization in the brain and the level and duration of glial cell activation. Some reports also describe the upregulation of RET and GFRα1 in glial cells, suggesting that GDNF could modulate neuroinflammation. [ABSTRACT FROM AUTHOR]