Regulation of Germ Cell Proliferation In Vitro by Activins, Follistatin, and Other Growth Factors

Author(s):  
Jennie P. Mather ◽  
Penelope E. Roberts ◽  
Lynne A. Krummen
1998 ◽  
Vol 40 (3) ◽  
pp. 173-178 ◽  
Author(s):  
Nina Atanassova ◽  
Ludmila Kancheva ◽  
Boris Somlev

2016 ◽  
Vol 201 (1) ◽  
pp. 1-13 ◽  
Author(s):  
Ruhui Tian ◽  
Shi Yang ◽  
Yong Zhu ◽  
Shasha Zou ◽  
Peng Li ◽  
...  

Vascular endothelial growth factor (VEGF) plays fundamental roles in testicular development; however, its function on testicular regeneration remains unknown. The objective of this study was to explore the roles VEGF/VEGFR2 signaling plays in mouse germ cells and in mouse testicular regeneration. VEGF and the VEGFR2 antagonist SU5416 were added to culture medium to evaluate their effects on spermatogonial stem cell line (C18-4 cells) proliferation. Testicular cells obtained from newborn male ICR mice were grafted into the dorsal region of male BALB/c nude mice. VEGF and SU5416 were injected into the graft sites to assess the effects of the VEGF and VEGFR2 signaling pathways on testicular reconstitution. The grafts were analyzed after 8 weeks. We found that VEGF promoted C18-4 proliferation in vitro, indicating its role in germ cell survival. HE staining revealed that seminiferous tubules were reconstituted and male germ cells from spermatogonia to spermatids could be observed in testis-like tissues 8 weeks after grafting. A few advantaged male germ cells, including spermatocytes and spermatids, were found in SU5416-treated grafts. Moreover, VEGF enhanced the expression of genes specific for male germ cells and vascularization in 8-week grafts, whereas SU5416 decreased the expression of these genes. SU5416-treated grafts had a lower expression of MVH and CD31, indicating that blockade of VEGF/VEGFR2 signaling reduces the efficiency of seminiferous tubule reconstitution. Collectively, these data suggest that VEGF/VEGFR2 signaling regulates germ cell proliferation and promotes testicular regeneration via direct action on germ cells and the enhancement of vascularization.


2004 ◽  
Vol 16 (9) ◽  
pp. 253
Author(s):  
S. M. Degen ◽  
P. G. Stanton ◽  
K. L. Loveland ◽  
S. J. Meachem

FSH is a key determinant of adult sperm output influencing both Sertoli and germ cell development. The aim of this study was to assess the impact of FSH action on Sertoli and germ cell proliferation and survival in vitro, and to identify FSH-regulated genes that may underpin these responses. Testis fragments from 17-day-old rats were cultured with recombinant human FSH for 2 or 24 h and then labelled with bromodeoxyuridine (BrdU) to identify proliferating cells. The testis fragments were then processed for analysis of cell numbers by stereology, BrdU incorporation by immunohistochemistry, and apoptosis by TUNEL. The TUNEL assay revealed that without FSH, spermatogonial apoptosis was induced to 195% and 179% (P�<�0.05) compared to fragments with FSH after 2 and 24 h, respectively. No difference in apoptosis was observed in spermatocyte or Sertoli cell populations at these time points. No differences in Sertoli or germ cell proliferation were observed with or without FSH. To understand how FSH mediates spermatogonial apoptosis the response of 5 testicular genes of interest was examined. Expression of cyclin D2 (cell cycle, G1-S), N-cadherin (N-Cad; adhesion molecule), Bax (pro-apoptotic), Bcl-w (anti-apoptotic), and stem cell factor (SCF; pro-apoptotic and other functions) was elevated to 151%, 348%, 209%, 258%, and 198%, respectively (all P�<�0.001), in fragments cultured without FSH for 24 h, compared to fragments with FSH. No gene expression differences were observed at 2 h, except for SCF, which was elevated to 135% (P�<�0.01). In conclusion, these studies have examined apoptosis and proliferation activities simultaneously in testis fragments in vitro, and demonstrated that FSH withdrawal induces both spermatogonial apoptosis and expression of testicular genes known to be involved in cell survival. This model will now be used to further investigate FSH-mediation of Sertoli and germ cell development.


2014 ◽  
Vol 223 (1) ◽  
pp. 79-91 ◽  
Author(s):  
Shabana Anjum ◽  
Amitabh Krishna ◽  
Kazuyoshi Tsutsui

The aim of this study was to evaluate the effects ofin vivoandin vitrotreatments with RFamide-related peptide 3 (RFRP3), a mammalian gonadotropin-inhibitory hormone ortholog, on testicular activities, i.e. spermatogenesis and steroidogenesis, in mice. Mice were treatedin vivowith different doses of RFRP3 (control: 0.02 μg, 0.2 μg, and 2.0 μg/day) for 8 days. Forin vitrostudy, the testes of mice were evaluated with different doses of RFRP3 (control: 1 and 10 ng/ml) with or without LH (control: 10 and 100 ng/ml) for 24 h at 37 °C. RFRP3 treatment produced significant changes in the body mass, circulating steroid level, and testicular activity in mice. RFRP3 treatment also caused dose-dependent histological changes in spermatogenesis, such as decline in germ cell proliferation and survival markers and increase in apoptotic markers in testis. Bothin vivoandin vitrostudies showed the inhibitory effect of RFRP3 on testosterone synthesis in the testis. RFRP3 inhibited the expression of the receptor for LH (LHCGR), STAR protein, cytochrome P450 side-chain cleavage (CYP11A1) and 3β-hydroxysteroid dehydrogenase in the testis, and testosterone secretion dose dependently. This study also suggested that the inhibitory effect of RFRP3 in the testis may be mediated through local production of GnRH. Thus, RFRP3 inhibits testicular steroidogenesis and spermatogenesis either indirectly through GnRH or by directly influencing germ cell proliferation, survival, and apoptosis.


2009 ◽  
Vol 21 (9) ◽  
pp. 88
Author(s):  
J. C. Young ◽  
A. Jaiprakash ◽  
S. Mithraprabhu ◽  
C. Itman ◽  
S. Kitazawa ◽  
...  

Testicular cancer, the second most common malignancy in young men, has a 95% cure rate but can result in infertility or subfertility. Its incidence has increased significantly in recent decades (1). This cancer is thought to arise during embryogenesis, based on the persistence of embryonic germ cell markers such as Blimp1 (2), Oct3/4 (3) and Nanog (3) in adult seminoma cells. TCam2 cells are a recently characterised in vitro seminoma model (4). We show by Q-PCR and immunofluorescence that they also express these early germ cell markers. TGFβ signaling plays a key role during germ cell development, and is implicated in the development of testicular cancers (5, 6). To investigate this further, we first determined whether the pathway is active in TCam2 cells. By Q-PCR we demonstrate expression of the TGFβ downstream transcription factors Smad 2, 3 and 4, and Activin type I and II receptors. Importantly, ActRIIA, which is undetectable in adult testicular germ cells, but readily detected in human foetal germ cells (7) and clinical seminoma samples (6), is readily detectable at both the mRNA and protein level in TCam2 cells. Furthermore, 24 hour treatment with Activin (5 and 50ng/ml) or BMP4 (5 and 50ng/ml) induces a 3-4 fold increase in ActRIIA mRNA levels, but not ActRIA, ActRIB or ActRIIB. Strikingly, in TCam2 cells BMP4 and to a lesser extent retinoic acid, but not activin, support survival and proliferation of TCam2 cells in the absence of serum. This is consistent with known roles of BMP4 and retinoic acid in enhancing murine foetal germ cell proliferation/self-renewal and survival (8, 9), and activin inhibition of foetal murine germ cell proliferation (10). This study is the first to demonstrate a functional response in seminoma cells consistent with their foetal germ cell-like identity and forms the basis for future mechanistic analyses of the role of TGFβ signaling in human testicular cancer.


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