PLZFposc-KITpos-delineated A1-A4-differentiating spermatogonia by subset and stage detection upon Bouin fixation

Advanced isolation, expansion and characterization research study on pig testicular cells during differentiation and proliferation

Spermatogenesis is the complex process of sperm production to transmit paternal genetic information to the subsequent generation. This process is determined by the collaboration of several germ and somatic cells, most importantly spermatogonia stem cells and Sertoli cells. To characterize germ and somatic cells in the tubule seminiferous contort in pig and consequently has an impact on the analysis of pig fertility. Germ cells were extracted from pig testis by enzymatic digestion before being expanded on Sandos inbred mice (SIM) embryo-derived thioguanine and ouabain resistant fibroblasts (STO) feeder layer supplemented with FGF, EGF, and GDNF. Immunohistochemistry (IHC) and immunocytochemistry (ICC) analysis for Sox9, Vimentin, and PLZF markers were performed to examine the generated colonies of pig testicular cells. Electron microscopy was also utilized to analyze the morphological features of the extracted pig germ cells. IHC analysis revealed that Sox9 and Vimentin were expressed in the basal compartment of the seminiferous tubules. Moreover, ICC results showed that the cells have low expression of PLZF while expressing Vimentin. The heterogeneity of the in vitro cultured cells was detected via morphological analysis by the electron microscope. In this experimental study, we tried to reveal exclusive information which obviously could be helpful for future success in the achievement of proper therapies against infertility and sterility as an important global issue.

Protective effects of human amniotic membrane derived mesenchymal stem cells (hAMSCs) secreted factors on mouse spermatogenesis and sperm chromatin condensation following unilateral testicular torsion

Testicular torsion is considered a urological disorder that requires immediate detorsion surgery. Ischemia/reperfusion (I/R) injury after testicular torsion detorsion causes of drastic impairment of spermatogenesis and infertility. Cell-free-based approaches seem to be a promising strategy to prevent I/R injury, they have more stable biological properties, and they contain paracrine factors of mesenchymal stem cells. The purpose of this study was to evaluate the protective effects of human amniotic membrane derived mesenchymal stem cells (hAMSCs) secreted factors on mouse sperm chromatin condensation and spermatogenesis improvement after I/R injury. hAMSCs were isolated and characterized by RT- PCR and flow cytometry, preparation of hAMSCs secreted factors was performed. Forty male mice were randomly divided into 4 groups: sham-operated, torsion detorsion, torsion detorsion+ intratesticular injection of DMEM/F-12, and torsion detorsion+ intratesticular injection of hAMSCs secreted factors. After one cycle of spermatogenesis, the mean number of germ cells, Sertoli, Leydig, myoid as well as tubular parameters, Johnson score, and spermatogenesis indexes were evaluated by H& E and PAS stainings. Sperm chromatin condensation and relative expression of c-kit and prm 1 genes were assessed by aniline blue staining and real-time PCR, respectively. The mean number of spermatogenic cells, Leydig, Myoid, Sertoli, spermatogenesis parameters, Johnson score, as well as germinal epithelial height and diameters of seminiferous tubules decreased significantly after I/R injury. The thickness of basement membrane and percentage of sperm with excessive histone significantly increased, while the relative expression of c-kit and prm 1 significantly decreased in torsion detorsion group (p<0.001). hAMSCs secreted factors remarkably restored normal sperm chromatin condensation, spermatogenesis parameters and histomorphometric organization of seminiferous tubules via intratesticular injection (p<0.001). Thus, hAMSCs secreted factors may potentially salvage torsion-detorsion-induced infertility.

Insights from the Applications of Single-Cell Transcriptomic Analysis in Germ Cell Development and Reproductive Medicine

Mechanistic understanding of germ cell formation at a genome-scale level can aid in developing novel therapeutic strategies for infertility. Germ cell formation is a complex process that is regulated by various mechanisms, including epigenetic regulation, germ cell-specific gene transcription, and meiosis. Gonads contain a limited number of germ cells at various stages of differentiation. Hence, genome-scale analysis of germ cells at the single-cell level is challenging. Conventional genome-scale approaches cannot delineate the landscape of genomic, transcriptomic, and epigenomic diversity or heterogeneity in the differentiating germ cells of gonads. Recent advances in single-cell genomic techniques along with single-cell isolation methods, such as microfluidics and fluorescence-activated cell sorting, have helped elucidate the mechanisms underlying germ cell development and reproductive disorders in humans. In this review, the history of single-cell transcriptomic analysis and their technical advantages over the conventional methods have been discussed. Additionally, recent applications of single-cell transcriptomic analysis for analyzing germ cells have been summarized.

PAX7 promotes CD49f-positive dairy goat spermatogonial stem cells' self-renewal

Spermatogenesis is a complex process that originates from and depends on the spermatogonial stem cells (SSCs). The number of SSCs is rare, which makes the separation and enrichment of SSCs difficult and inefficient. The transcription factor PAX7 maintains fertility in normal spermatogenesis in mice. However, for large animals, much less is known about the SSCs' self-renewal regulation, especially in dairy goats. We isolated and enriched the CD49f-positive and negative dairy goat testicular cells by magnetic-activated cell sorting strategies. The RNA- sequencing and experimental data revealed that cells with a high CD49f and PAX7 expression are undifferentiated spermatogonia in goat testis. Our findings indicated that ZBTB16 (PLZF), PAX7, LIN28A, BMPR1B, FGFR1, and FOXO1 were expressed higher in CD49f-positive cells as compared to negative cells and goat fibroblasts cells. The expression and distribution of PAX7 in dairy goat also have been detected, which gradually decreased in testis tissue along with the increasing age. When the PAX7 gene was overexpressed in dairy goat immortal mGSCs-I-SB germ cell lines, the expression of PLZF, GFRα1, ID4, and OCT4 was upregulated. Together, our data demonstrated that there is a subset of spermatogonial stem cells with a high expression of PAX7 among the CD49f⁺ spermatogonia, and PAX7 can maintain the self-renewal of CD49f-positive SSCs.