The self-renewal and differentiation of adult stem cells are closely related to their niches. Naturally, spermatogonial stem cells (SSCs) are the only adult stem cells in the body, which can transfer genetic information into the offspring. An insight into the modulation of the self-renewal and differentiation of SSCs can help elucidate the mechanisms of spermatogenesis and investigate the proliferation and differentiation of other adult stem cells. Therefore, the SSC system provides an ideal model for researches on the adult stem cell niche. More and more evidence indicates that the self-renewal and differentiation of SSCs are regulated by their niches. Based on our previous work and other related findings recently reported, this article presents an overview on the biological properties of SSC niches and their relationship with the self-renewal and differentiation of SSCs, focusing on the basic properties and components of SSC niches and various regulatory factors they produce.
Animals ; Cell Differentiation ; Male ; Spermatogenesis ; Spermatogonia ; cytology ; Stem Cell Niche ; Stem Cells ; cytology

Spermatogonial stem cells (SSCs) play an important role in spermatogenesis and have a unique mode of replication. A single SSC can produce two differentiating cells, or one stem cell and one differentiating cell. The self-renewal and differentiation of SSCs are precisely regulated as relating the niche of SSCs, glial cell line-derived neurotrophic factor, and several signaling pathways. This article reviews the self-renewal and differentiation of SSCs and their regulation mechanisms, which may offer a deeper insight into spermatogenesis and male infertility and pave a theoretical ground for studying testicular tumorigenesis and searching for new potential approaches to the treatment of testicular cancer and other related diseases.
Adult Stem Cells ; cytology ; Cell Differentiation ; Cells, Cultured ; Humans ; Male ; Spermatogenesis ; Spermatogonia ; cytology ; Stem Cell Transplantation

OBJECTIVETo study the feasibility of spermatogonial stem cell allotransplantation.

METHODSThe spermatogonial stem cell allotransplantation was performed, without the use of immune inhibitor, in KM mice of similar gene types, and the spermatogenesis in recipients' testes was evaluated. The right testes were pierced for transplantation while the left ones were taken as control.

RESULTSAllotransplant germ cells in KM mice can recover normal function of spermatogenesis in the transplanted testis without any immune suppression.

CONCLUSIONAllospermatogonial stem cells can be transplanted successfully among KM mice.

Animals ; Male ; Mice ; Models, Animal ; Spermatogonia ; cytology ; transplantation ; Stem Cell Transplantation ; Testis ; cytology ; Transplantation, Homologous

In recent years, people have paid more attention to the spermatogonial stem cells that have the capacity for self renewal and multilineage differentiation and produce daughter cells that can expand and differentiate into spermatozoa under the adjustment of self genes and external signal. This article reviews recent advances in studies of enrichment and original selection of the spermatogonial stem cells. This review also summarizes some control factors in proliferation and transplantation techniques.
Animals ; Cell Proliferation ; Humans ; Male ; Rats ; Spermatogonia ; cytology ; Stem Cell Transplantation ; Stem Cells ; cytology

Animals ; Cell Culture Techniques ; methods ; Cells, Cultured ; Cryopreservation ; Male ; Mice ; Spermatogonia ; cytology ; Stem Cells ; cytology

Stem cell can both self-renew and have the ability to differentiate into one or more cell types that perform normal tissue/organ function throughout life, including embryonic stem cell and adult stem cell. The treatment with stem cells will be widely used in the future. This article reviews recent advances in studies of the use of embryonic stem cells and spermatogonial stem cells in male reproduction.
Embryonic Stem Cells ; transplantation ; Humans ; Male ; Spermatogonia ; cytology ; Stem Cell Transplantation ; trends ; Stem Cells ; cytology

Clinically many patients with non-obstructive azoospermia cannot benefit from assisted reproductive technology for absence of spermatozoa. However, the achievement in the studies of spermatogonial stem cells has brought hope to this cohort. This article reviews the molecular mechanisms of the proliferation and differentiation of spermatogonial stem cells, in such aspects as related genes, growth factors, and so on.
Azoospermia ; therapy ; Cell Differentiation ; Cell Proliferation ; Humans ; Male ; Spermatogonia ; cytology ; Stem Cells ; cytology

OBJECTIVETo establish a long-term culture system for mouse spermatogonial stem cells (SSCs) and to discuss the key factor that supports mouse SSC self-renewal and proliferation.

METHODSTestis cells from 4-6 days postpartum male transgenic BALB/c mce were collected by a modified two-step enzymatic digestion method and plated on 0. 2% elatin-coated tissue culture plates. The germ cells were enriched by differential adherence selections after respectively incubated for 1, 5 and 24 h and then plated on the mitomycin C-inactivated mouse embryonic fibroblast (MEF) feeder layer. The basal culture medium was StemPro-34 SFM supplemented with other 15 nutrient factors. The 20 ng/ml Glial cell line-derived neurotrophic factor (GDNF), 10 ng/ml basic fibroblast growth factor (bFGF) and 200 ng/ml GDNF-family receptor alpha 1 (GFRalpha1) were added to the serum-free medium to promote SSC proliferation. Several important surface markers and special genes were examined by immunocytochemical staining and RT-PCR analysis.

RESULTSAfter 3-4 days culture on the MEF feeder, SSCs proliferated continuously and formed typical colonies. SSCs from the BALB/c mice could be cultured in a steady state for 3 months. Immunocytochemical staining showed that Oct4 was specifically expressed in the cultured SSC nucleus and GFRalpha1 strongly expressed on the surface of the membrane. RT-PCR confirmed that the cultured SSCs expressed Oct-4, GFRalpha1, Sox2 and several other special genes resembling undifferentiated spermatogonia.

CONCLUSIONSSCs from BALB/c mice could be cultured in the improved culture system for 3 months. This culture system could help further understand the regulating mechanism of SSCs and might provide an opportunity for the treatment of male infertility by SSC transplantation.

Animals ; Cell Culture Techniques ; methods ; Male ; Mice ; Mice, Inbred BALB C ; Spermatogonia ; cytology ; Stem Cells ; cytology

OBJECTIVETo study the expression of Annexin A7 in the mouse testis, especially in different types of spermatogonia.

METHODSWe prepared Annexin A7 recombinant protein using prokaryotic expression, adsorbed the Annexin A7 antibody with it after identified by mass spectrometry, and detected the expression of Annexin A7 by Western-blot and immunohistochemistry.

RESULTSAnnexin A7 was expressed in a development-dependent manner in the spermatogonia of the prepubertal mice and in the type-A single (As) and type-A paired (Apr) spermatogonia of adult mice. These results were confirmed by the co-localization of Annexin A7 and Stra8, a known determinant of differentiated spermatogonial stem cells (SSCs).

CONCLUSIONAnnexin A7 is the internal factor of As and Apr spermatogonia, which might be involved in the biological functions of SSCs.

Animals ; Annexin A7 ; metabolism ; Male ; Mice ; Spermatogonia ; cytology ; metabolism ; Stem Cells ; cytology ; metabolism

OBJECTIVETo investigate the methods and conditions for the isolation, purification and culture of human spermatogonial stem cells (SSCs) on the feeder layer cells of human embryonic fibroblasts (hEFs).

METHODSSSCs isolated and purified from normal human fetal testicular tissues by sequential two-step enzyme digestion and Percoll uncontinuous density gradient centrifugation were cultured on the feeder layer cells of hEFs isolated from 5-9 weeks old human embryos. The surface markers SSEA-1 and OCT4 of the SSCs were detected by immunohistochemistry; the alkaline phosphatase (AKP) activity of the SSC clones measured; and the expressions of the SSC-related genes determined by RT-PCR.

RESULTSSSCs survived, proliferated and formed colonies on the feeder layers, and the colonies were highly positive for SSEA-1 and OCT4, with strong AKP activity and high expressions of the SSC-related genes.

CONCLUSIONThe feeder layer of hEFs supports the growth of human spermatogonial stem cells.

Cell Culture Techniques ; methods ; Cell Differentiation ; Cells, Cultured ; Embryo, Mammalian ; cytology ; Fibroblasts ; cytology ; Humans ; Male ; Spermatogonia ; cytology ; Stem Cells ; cytology