scholarly journals Hedgehog signalling promotes germ cell survival in the rat testis

Reproduction ◽  
2011 ◽  
Vol 142 (5) ◽  
pp. 711-721 ◽  
Author(s):  
Juho-Antti Mäkelä ◽  
Vuokko Saario ◽  
Sonia Bourguiba-Hachemi ◽  
Mirja Nurmio ◽  
Kirsi Jahnukainen ◽  
...  
Keyword(s):  
Cell Differentiation ◽  
Germ Cell ◽  
Germ Cells ◽  
Tyrosine Kinases ◽  
Negative Regulator ◽  
Mrna Levels ◽  
Paracrine Signalling ◽  
Rat Testis ◽  
Germ Cell Differentiation

Hedgehog (Hh) signalling has a crucial role in testis development. Sertoli cell-derived desert hedgehog (DHH) guides the formation of testis cords and differentiation of foetal-type Leydig cells. Dhh mutant mice are infertile due to a block in germ cell differentiation, hypogonadism and hypoandrogenism. Hh signalling pathway components are also expressed in postnatal testis. In the rat testis the transcription factor of the Hh pathway, glioma-associated oncogene homologue (GLI1), is expressed by a wide variety of germ cells. This suggests that Hh signalling is involved in spermatogenesis at many different levels. Our data show that canonical Hh signalling is turned off in early condensing spermatids that strongly express the negative regulator of the pathway, suppressor of fused (SUFU). Most of the Hh pathway specific mRNAs display the highest values in stages II–VI of the rat seminiferous epithelial cycle. The key endocrine regulator of germ cell differentiation, FSH, down-regulates Dhh mRNA levels in vitro. Hh signalling inhibition in vitro leads to massive apoptosis of germ cells. In prepubertal rat testis imatinib mesylate-induced inhibition of tyrosine kinases impinges on Dhh transcript levels and Hh signalling. Our data indicate that Hh signalling is part of the paracrine signalling network in the rat testis. It promotes the survival of germ cells and is suppressed by FSH.

scholarly journals Critical role of Emx2 in the pluripotency – differentiation transition in male gonocytes via regulation of FGF9/NODAL pathway

Reproduction ◽  
2016 ◽  
Vol 151 (6) ◽  
pp. 673-681 ◽  
Author(s):  
Ma Tian-Zhong ◽  
Chen Bi ◽  
Zhang Ying ◽  
Jing Xia ◽  
Peng Cai-Ling ◽  
...  
Keyword(s):  
Cell Differentiation ◽  
Mouse Model ◽  
Germ Cell ◽  
Germ Cells ◽  
Critical Role ◽  
Genital Ridge ◽  
Germ Cell Differentiation ◽  
Pluripotency Markers

Abstract Emx2 deletion impairs the growth and maintenance of the genital ridge. However, its role in subsequent germ cell differentiation during embryonic stages is unknown. Using a tamoxifen-inducible Cre-loxP mouse model (Emx2flox/flox, Cre-ERTM, hereafter called as Emx2 knockdown), we showed that germ cell differentiation was impaired in Emx2-knockdown testes. Representative characteristics of male germ cell differentiation, including a reduced ability to form embryonic germ (EG) cell colonies in vitro, down-regulation of pluripotency markers and G1/G0 arrest, did not occur in Emx2-knockdown testes. Furthermore, FGF9 and NODAL signalling occurred at abnormally high levels in Emx2-knockdown testes. Both blocking FGF9 signalling with SU5402 and inhibiting NODAL signalling with SB431542 allowed germ cells from Emx2-knockdown testes to differentiate in vitro. Therefore, EMX2 in somatic cells is required to trigger germ cell differentiation in XY foetuses, posterior to its previously reported role in the growth and maintenance of the genital ridge.

scholarly journals Arrest of WNT/β-catenin signaling enables the transition from pluripotent to differentiated germ cells in mouse ovaries

2021 ◽  
Vol 118 (30) ◽  
pp. e2023376118
Author(s):  
Morgane Le Rolle ◽  
Filippo Massa ◽  
Pam Siggers ◽  
Laurent Turchi ◽  
Agnès Loubat ◽  
...  
Keyword(s):  
Cell Differentiation ◽  
Germ Cell ◽  
Sexual Reproduction ◽  
Germ Cells ◽  
Molecular Basis ◽  
Primordial Germ Cells ◽  
Negative Regulator ◽  
Loss Of Function ◽  
Timely Manner ◽  
Germ Cell Differentiation

Germ cells form the basis for sexual reproduction by producing gametes. In ovaries, primordial germ cells exit the cell cycle and the pluripotency-associated state, differentiate into oogonia, and initiate meiosis. Despite the importance of germ cell differentiation for sexual reproduction, signaling pathways regulating their fate remain largely unknown. Here, we show in mouse embryonic ovaries that germ cell–intrinsic β-catenin activity maintains pluripotency and that its repression is essential to allow differentiation and meiosis entry in a timely manner. Accordingly, in β-catenin loss-of-function and gain-of-function mouse models, the germ cells precociously enter meiosis or remain in the pluripotent state, respectively. We further show that interaction of β-catenin and the pluripotent-associated factor POU5F1 in the nucleus is associated with germ cell pluripotency. The exit of this complex from the nucleus correlates with germ cell differentiation, a process promoted by the up-regulation of Znrf3, a negative regulator of WNT/β-catenin signaling. Together, these data identify the molecular basis of the transition from primordial germ cells to oogonia and demonstrate that β-catenin is a central gatekeeper in ovarian differentiation and gametogenesis.

scholarly journals Cell-type-specific regulation of genes involved in testicular lipid metabolism: fatty acid-binding proteins, diacylglycerol acyltransferases, and perilipin 2

Reproduction ◽  
2013 ◽  
Vol 146 (5) ◽  
pp. 471-480 ◽  
Author(s):  
Gerardo M Oresti ◽  
Jesús García-López ◽  
Marta I Aveldaño ◽  
Jesús del Mazo
Keyword(s):  
Fatty Acid ◽  
Cell Differentiation ◽  
Germ Cell ◽  
Germ Cells ◽  
Sertoli Cells ◽  
Fatty Acid Binding Proteins ◽  
Cell Type ◽  
Fatty Acid Binding ◽  
Germ Cell Differentiation ◽  
Perilipin 2

Male germ cell differentiation entails the synthesis and remodeling of membrane polar lipids and the formation of triacylglycerols (TAGs). This requires fatty acid-binding proteins (FABPs) for intracellular fatty acid traffic, a diacylglycerol acyltransferase (DGAT) to catalyze the final step of TAG biosynthesis, and a TAG storage mode. We examined the expression of genes encoding five members of the FABP family and two DGAT proteins, as well as the lipid droplet protein perilipin 2 (PLIN2), during mouse testis development and in specific cells from seminiferous epithelium.Fabp5expression was distinctive of Sertoli cells and consequently was higher in prepubertal than in adult testis. The expression ofFabp3increased in testis during postnatal development, associated with the functional differentiation of interstitial cells, but was low in germ cells.Fabp9, together withFabp12, was prominently expressed in the latter. Their transcripts increased from spermatocytes to spermatids and, interestingly, were highest in spermatid-derived residual bodies (RB). Both Sertoli and germ cells, which produce neutral lipids and store them in lipid droplets, expressedPlin2. Yet, whileDgat1was detected in Sertoli cells,Dgat2accumulated in germ cells with a similar pattern of expression asFabp9. These results correlated with polyunsaturated fatty acid-rich TAG levels also increasing with mouse germ cell differentiation highest in RB, connecting DGAT2 with the biosynthesis of such TAGs. The age- and germ cell type-associated increases inFabp9,Dgat2, andPlin2levels are thus functionally related in the last stages of germ cell differentiation.

scholarly journals Ligand–Receptor Interactions Elucidate Sex-Specific Pathways in the Trajectory From Primordial Germ Cells to Gonia During Human Development

2021 ◽  
Vol 9 ◽  
Author(s):  
Arend W. Overeem ◽  
Yolanda W. Chang ◽  
Jeroen Spruit ◽  
Celine M. Roelse ◽  
Susana M. Chuva De Sousa Lopes
Keyword(s):  
Germ Cell ◽  
Signaling Pathways ◽  
Germ Cells ◽  
Tyrosine Kinases ◽  
Intracellular Localization ◽  
Primordial Germ Cells ◽  
Cell Lineage ◽  
Systematic Analysis ◽  
Receptor Interactions

The human germ cell lineage originates from primordial germ cells (PGCs), which are specified at approximately the third week of development. Our understanding of the signaling pathways that control this event has significantly increased in recent years and that has enabled the generation of PGC-like cells (PGCLCs) from pluripotent stem cells in vitro. However, the signaling pathways that drive the transition of PGCs into gonia (prospermatogonia in males or premeiotic oogonia in females) remain unclear, and we are presently unable to mimic this step in vitro in the absence of gonadal tissue. Therefore, we have analyzed single-cell transcriptomics data of human fetal gonads to map the molecular interactions during the sex-specific transition from PGCs to gonia. The CellPhoneDB algorithm was used to identify significant ligand–receptor interactions between germ cells and their sex-specific neighboring gonadal somatic cells, focusing on four major signaling pathways WNT, NOTCH, TGFβ/BMP, and receptor tyrosine kinases (RTK). Subsequently, the expression and intracellular localization of key effectors for these pathways were validated in human fetal gonads by immunostaining. This approach provided a systematic analysis of the signaling environment in developing human gonads and revealed sex-specific signaling pathways during human premeiotic germ cell development. This work serves as a foundation to understand the transition from PGCs to premeiotic oogonia or prospermatogonia and identifies sex-specific signaling pathways that are of interest in the step-by-step reconstitution of human gametogenesis in vitro.

scholarly journals Interactome analyses reveal profound proteasome structural and functional rearrangements throughout mammalian spermatogenesis

2021 ◽  
Author(s):  
Dusan Zivkovic ◽  
Angelique Sanchez Dafun ◽  
Thomas Menneteau ◽  
Adrien Schahl ◽  
Sandrine Lise ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Germ Cell ◽  
Germ Cells ◽  
Protein Assembly ◽  
Homologous Chromosomes ◽  
High Proteolytic Activity ◽  
Complex Processes ◽  
Germ Cell Differentiation ◽  
Mechanism Function

During spermatogenesis, spermatogonia undergo a series of mitotic and meiotic divisions on their path to spermatozoa. To achieve this, a succession of complex processes requiring high proteolytic activity are in part orchestrated by the proteasome. The spermatoproteasome (s20S) is a proteasome subtype specific to the developing gametes, in which the gamete-specific α4s subunit replaces the α4 isoform found in the constitutive proteasome (c20S). Although the s20S is conserved across species and was shown to be crucial for germ cell development, its mechanism, function and structure remain incompletely characterized. Here, we used advanced mass spectrometry (MS) methods to map the composition of proteasome complexes and their interactomes throughout spermatogenesis. We observed that the s20S becomes highly activated as germ cells enter meiosis, mainly through association with proteasome activators PA200 and 19S. Additionally, the proteasome population shifts from predominantly c20S (98%) to predominantly s20S (>82-92%) during differentiation, presumably due to the shift from α4 to α4s expression. We confirmed that s20S, but not c20S, interacts with components of the synaptonemal complex, the multi-protein assembly that connects homologous chromosomes during meiosis. In vitro, s20S preferentially bind to 19S, and displayed higher trypsin- and chymotrypsin-like activities, both with and without PA200 activation. Moreover, using MS methods to monitor protein dynamics, we identified significant differences in domain flexibility between α4 and α4s. We propose that these differences induced by α4s incorporation result in significant changes in the way the s20S interacts with its partners, and dictate its role in germ cell differentiation.

scholarly journals Abnormal Meiosis Initiation in Germ Cell Caused by Aberrant Differentiation of Gonad Somatic Cell

2019 ◽  
Vol 2019 ◽  
pp. 1-8
Author(s):  
Min Chen ◽  
Min Chen ◽  
Suren Chen ◽  
Jingjing Zhou ◽  
Fangfang Dong ◽  
...  
Keyword(s):  
Cell Differentiation ◽  
Germ Cell ◽  
Somatic Cell ◽  
Germ Cells ◽  
Somatic Cells ◽  
Ectopic Expression ◽  
Genital Ridge ◽  
Male And Female ◽  
Germ Cell Differentiation ◽  
Exact Function

The interaction between germ cell and somatic cell plays important roles in germ cell development. However, the exact function of gonad somatic cell in germ cell differentiation is unclear. In the present study, the function of gonad somatic cell in germ cell meiosis was examined by using mouse models with aberrant somatic cell differentiation. In Wt1R394W/R394W mice, the genital ridge is absent due to the apoptosis of coelomic epithelial cells. Interestingly, in both male and female Wt1R394W/R394W germ cells, STRA8 was detected at E12.5 and the scattered SYCP3 foci were observed at E13.5 which was consistent with control females. In Wt1-/flox; Cre-ERTM mice, Wt1 was inactivated by the injection of tamoxifen at E9.5 and the differentiation of Sertoli and granulosa cells was completely blocked. We found that most germ cells were located outside of genital ridge after Wt1 inactivation. STRA8, SYCP3, and γH2AX proteins were detected in germ cells of both male and female Wt1-/flox; Cre-ERTM gonads, whereas no thread-like SYCP3 signal was observed. Our study demonstrates that aberrant development of gonad somatic cells leads to ectopic expression of meiosis-associated genes in germ cells, but meiosis was arrested before prophase I. These results suggest that the proper differentiation of gonad somatic cells is essential for germ cell meiosis.

182 In Vitro Derivation of Male Germ Cells from Bovine Bone Marrow-Derived Mesenchymal Stem Cells

2018 ◽  
Vol 30 (1) ◽  
pp. 231
Author(s):  
J. Cortez ◽  
J. Bahamonde ◽  
J. Palomino ◽  
M. De los Reyes ◽  
C. Torres ◽  
...  
Keyword(s):  
Stem Cells ◽  
Bone Marrow ◽  
Mesenchymal Stem Cells ◽  
Germ Cell ◽  
Mrna Expression ◽  
Male Germ Cell ◽  
Bovine Bone ◽  
Mrna Levels ◽  
Germ Cell Differentiation

During the last few years, the in vitro derivation of germ cell lineages from stem cells has emerged as an exciting new strategy for obtaining mature gametes. In vitro gamete derivation technology has potential applications as an alternative method for dissemination of elite animal genetics, production of transgenic animals, and conservation of endangered species. Germ cell differentiation and gametogenesis is a complex process and potential of different stem cell donors (i.e. SSC, ESC, iPSC) for in vitro male germ cell derivation has been inconsistent. Mesenchymal stem cells (MSC) may be suitable candidates for in vitro gamete derivation considering their (1) plasticity that is not limited to mesodermal derivatives, (2) availability of abundant tissues sources for isolation, (3) high proliferative potential, (4) simple and inexpensive isolation, and (5) high potential for cell therapy, including autologous or allogenic transplantation. The present study aimed to induce differentiation of MSC isolated from bone marrow derived from bovine male fetuses (bfMSC) into the germ cell lineage using an in vitro approach based on the exogenous effect of retinoic acid (RA) and bone morphogenetic protein 4 (BMP4). Differentiation media consisted in control media (DMEM with high glucose plus 10% fetal bovine serum, 100 IU mL−1 penicillin, 100 μg mL−1 streptomycin, and 0.25 μg mL−1amphotericin B) supplemented with RA (0.01, 0.1, or 1 µM) or BMP4 (10, 50, or 100 ng mL−1). Cell samples were obtained from differentiating and control bfMSC cultures and analysed for expression of housekeeping genes β-ACTIN and GAPDH, pluripotent genes OCT4 and NANOG, germ cell genes FRAGILLIS, STELLA, and VASA, male germ cell genes DAZL, PIWIl2, and STRA8, and meiotic biomarker SCP3 by quantitative-PCR (Q-PCR). OCT4, NANOG, and DAZL were immunodetected in undifferentiated and differentiated bfMSC using flow-cytometry analysis. The mRNA expression of DAZL was activated by RA or BMP4 supplementation, although no differences (P > 0.05) were detected among different concentrations. DAZL and NANOG mRNA levels increased (P < 0.05) from Day 7 to Day 21 during supplementation of RA (0.1 μM). In comparison, DAZL mRNA levels increased (P < 0.05) at Day 14 during supplementation of BMP4 (100 ng). OCT4 and SCP3 mRNA levels were not affected by RA or BMP4 treatments. Transcripts of FRAGILLIS, STELLA, VASA, PIWIl2, and STRA8 were not detected in control or differentiated bfMSC. Higher (P < 0.05) percentages of undifferentiated bfMSC were positive for NANOG (80.6%) and OCT4 (83.4%). DAZL- and NANOG-positive cells were 2.1% and 2.9%, and 95.9% and 97.8% at Days 0 and 21 of RA treatment, respectively. Data indicated that expression of germ cell biomarker DAZL in bfMSC is activated and increased after in vitro supplementation of RA and BMP4. Moreover, NANOG mRNA levels were regulated by RA treatment. Similar levels of SCP3 mRNA expression suggest that differentiated bfMSC were not induced into meiosis. Thus, exposure of bfMSC to RA or BMP4 under in vitro conditions might induce an early stage of premeiotic germinal differentiation.

Sign in / Sign up

Export Citation Format

Share Document