Evaluating the behavior of cultured sertoli cells in the presence and absence of spermatogonial stem cell

Fetal bovine serum (FBS) enhances proliferation and colonization of caprine spermatogonial stem cells

Enrichment of cell suspension with germ cells prior to injection into recipient seminiferous tubules is of importance in spermatogonial stem cells (SSCs) transplantation. Fetal bovine serum (FBS) is the most widely used growth supplement for cell cultures, primarily because of its high levels of growth stimulatory factors and low levels of growth inhibitory factors. This study was undertaken to investigate the effect of serum concentration on colony formation and development of different types of SSC colonies with respect to passage number. Cells were isolated from pre-pubertal buck testes by two step enzymatic digestion method. The filtered cells were enriched by differential adherence selection method. Cells were then randomly divided into 8 groups, depending on concentration of FBS in culture medium ranging from 0% to 35%. In experiment 1, effect of different concentrations of FBS on total number pSSCs with reference to differential plating was observed while in experiment 2, effect of different concentrations of FBS on types of pSSC colonies with respect to passage number was observed. No colony formation was observed in control group (0% FBS) while significantly higher number of single, paired, cluster and rosette colonies observed were with 20% FBS group in differential 2 (D2) as compared to other groups. Alkaline phosphatase staining and immunocytochemistry staining (PGP9.5 and OCT4) were positive in SSCs colonies. The growth rate of the culture was significantly and consistently higher with 20% FBS.

Characterization and population dynamics of germ cells in adult macaque testicular cultures

BACKGROUND

From a biological and clinical perspective, it is imperative to establish primate spermatogonial cultures. Due to limited availability of human testicular tissues, the macaque (Macaca fascicularis) was employed as non-human primate model. The aim of this study was to characterize the expression of somatic as well as germ cell markers in testicular tissues and to establish macaque testicular primary cell cultures.

MATERIALS AND METHODS

Characterization of macaque testicular cell population was performed by immunohistochemical analyses for somatic cell markers (SOX9, VIM, SMA) as well as for germ cell markers (UTF1, MAGEA4, VASA). Testicular cells from adult macaque testes (n = 4) were isolated and cultured for 21 days using three stem cell culture media (SSC, PS and SM). An extended marker gene panel (SOX9, VIM, ACTA2; UTF1, FGFR3, MAGEA4, BOLL, DDX4) was then employed to assess the changes in gene expression levels and throughout the in vitro culture period. Dynamics of the spermatogonial population was further investigated by quantitative analysis of immunofluorescence-labeled MAGEA4-positive cells (n = 3).

RESULTS

RNA expression analyses of cell cultures revealed that parallel to decreasing SOX9-expressing Sertoli cells, maintenance of VIM and ACTA2-expressing somatic cells was observed. Expression levels of germ cell marker genes UTF1, FGFR3 and MAGEA4 were maintained until day 14 in SSC and SM media. Findings from MAGEA4 immunofluorescence staining corroborate mRNA expression profiling and substantiate the overall maintenance of MAGEA4-positive pre- and early meiotic germ cells until day 14.

CONCLUSIONS

Our findings demonstrate maintenance of macaque germ cell subpopulations in vitro. This study provides novel perspective and proof that macaques could be used as a research model for establishing in vitro germ cell-somatic cell cultures, to identify ideal culture conditions for long-term maintenance of primate germ cell subpopulation in vitro.

Manipulation of spermatogonial stem cells in livestock species

We are entering an exciting epoch in livestock biotechnology during which the fundamental approaches (such as transgenesis, spermatozoa cryopreservation and artificial insemination) will be enhanced based on the modern understanding of the biology of spermatogonial stem cells (SSCs) combined with the outstanding recent advances in genomic editing technologies and in vitro cell culture systems. The general aim of this review is to outline comprehensively the promising applications of SSC manipulation that could in the nearest future find practical application in livestock breeding. Here, we will focus on 1) the basics of mammalian SSC biology; 2) the approaches for SSC isolation and purification; 3) the available in vitro systems for the stable expansion of isolated SSCs; 4) a discussion of how the manipulation of SSCs can accelerate livestock transgenesis; 5) a thorough overview of the techniques of SSC transplantation in livestock species (including the preparation of recipients for SSC transplantation, the ultrasonographic-guided SSC transplantation technique in large farm animals, and the perspectives to improve further the SSC transplantation efficiency), and finally, 6) why SSC transplantation is valuable to extend the techniques of spermatozoa cryopreservation and/or artificial insemination. For situations where no reliable data have yet been obtained for a particular livestock species, we will rely on the data obtained from studies conducted in rodents because the knowledge gained from rodent research is translatable to livestock species to a great extent. On the other hand, we will draw special attention to situations where such translation is not possible.