scholarly journals Initiation of testicular tubulogenesis is controlled by neurotrophic tyrosine receptor kinases in a three-dimensional Sertoli cell aggregation assay

Reproduction ◽  
2008 ◽  
Vol 136 (4) ◽  
pp. 459-469 ◽  
Author(s):  
Kathrin Gassei ◽  
Jens Ehmcke ◽  
Stefan Schlatt

The first morphological sign of testicular differentiation is the formation of testis cords. Prior to cord formation, newly specified Sertoli cells establish adhesive junctions, and condensation of somatic cells along the surface epithelium of the genital ridge occurs. Here, we show that Sertoli cell aggregation is necessary for subsequent testis cord formation, and that neurotrophic tyrosine kinase receptors (NTRKs) regulate this process. In a three-dimensional cell culture assay, immature rat Sertoli cells aggregate to form large spherical aggregates (81.36±7.34 μm in diameter) in a highly organized, hexagonal arrangement (376.95±21.93 μm average distance between spherical aggregates). Exposure to NTRK inhibitors K252a and AG879 significantly disrupted Sertoli cell aggregation in a dose-dependent manner. Sertoli cells were prevented from establishing cell–cell contacts and from forming spherical aggregates.In vitro-derived spherical aggregates were xenografted into immunodeficient nude mice to investigate their developmental potential. In controls, seminiferous tubule-like structures showing polarized single-layered Sertoli cell epithelia, basement membranes, peritubular myoid cells surrounding the tubules, and lumen were observed in histological sections. By contrast, grafts from treatment groups were devoid of tubules and only few single Sertoli cells were present in xenografts after 4 weeks. Furthermore, the grafts were significantly smaller when Sertoli cell aggregation was disrupted by K252ain vitro(20.87 vs 6.63 mg;P<0.05). We conclude from these results that NTRK-regulated Sertoli–Sertoli cell contact is essential to the period of extensive growth and remodeling that occurs during testicular tubulogenesis, and our data indicate its potential function in fetal and prepubertal testis differentiation.

1995 ◽  
Vol 108 (3) ◽  
pp. 917-925
Author(s):  
N. Gerard ◽  
A. Corlu ◽  
B. Kneip ◽  
H. Kercret ◽  
M. Rissel ◽  
...  

We have identified a liver-regulating protein involved in cell contact-mediated regulation of Sertoli cell function by primary spermatocytes in rat testis. Liver-regulating protein was studied using monoclonal antibody L8 prepared from rat primitive biliary epithelial cells. This molecule was located in vivo at the interface of Sertoli cells and spermatocytes, and expressed in a stage-dependent manner (expression peaked on leptotene-zygotene spermatocytes). In vitro, the liver-regulating protein was found on Sertoli cell, spermatocyte and early spermatid membranes. Immunoaffinity procedures revealed two peptides of 85 and 73 kDa for Sertoli cells, while spermatocytes and spermatids displayed a single smaller peptide of 56 kDa. The involvement of the liver-regulating protein in cell interaction-mediated regulation of Sertoli cell was assessed in vitro by tracing Sertoli cell transferrin and inhibin secretion, as well as mRNA synthesis in spermatocyte-Sertoli cell cocultures and in rat liver biliary epithelial cell-Sertoli cell cocultures, performed in the presence or absence of monoclonal antibody L8. Inhibition of the spermatocyte- and liver biliary epithelial cell-stimulated secretion of transferrin and inhibin by Sertoli cells was observed in the presence of antibody, whereas spermatocyte adhesiveness was unchanged. Using northern blot analysis, the steady state levels of transferrin mRNA decreased when the anti-liver-regulating protein antibody was added to the Sertoli cell-spermatocyte cocultures or to the Sertoli cell-liver biliary epithelial cell cocultures. The data demonstrate the role of the liver-regulating protein in cell-cell contact-mediated regulation of Sertoli function by primary spermatocytes and the important implications of this cell contact-dependent control in testicular activity.


1986 ◽  
Vol 103 (3) ◽  
pp. 1109-1119 ◽  
Author(s):  
G C Enders ◽  
J H Henson ◽  
C F Millette

We have examined the adhesion of primary Sertoli cells to a seminiferous tubule basement membrane (STBM) preparation in vitro. The STBM isolation procedure (Watanabe, T.K., L.J. Hansen, N.K. Reddy, Y.S. Kanwar, and J.K. Reddy, 1984, Cancer Res., 44:5361-5368) yields segments of STBM that retain their histotypic form in both three-dimensional tubular geometry and ultrastructural appearance. The STBM sleeves contain two laminae: a thick, inner basal lamina that was formed in vivo between Sertoli cells and peritubular myoid cells; and a thinner, outer basal lamina that was formed between myoid cells and sinusoidal endothelial cells. Characterization by immunofluorescence and SDS PAGE revealed that the isolated STBM retained fibronectin, laminin, and putative type IV collagen among its many components. When the STBM sleeves were gently shaken with an enriched fraction of primary Sertoli cells, the Sertoli cells bound preferentially to the lumenal basal lamina at the ends of the STBM sleeves. Few Sertoli cells bound to either the outer basal lamina of the STBM sleeves or to vascular extracellular matrix material which contaminated the STBM preparation. 3T3 cells, in contrast, bound to all surfaces of the STBM sleeves. Pretreatment of the STBM sleeves with proteases, 0.1 M Na metaperiodate, 4 M guanidine HCl, or heating to 80 degrees-90 degrees C inhibited lumenal Sertoli cell binding, but binding was not inhibited by chondroitinase ABC, heparinase, hyaluronidase, or 4 M NaCl. The lumenal Sertoli cell binding occurred in the presence or absence of added soluble laminin, but not fibronectin. The addition of soluble laminin, but not fibronectin, restored random binding of Sertoli cells to trypsinized STBM sleeves. Our in vitro model system indicates that Sertoli cells recognize differences in two basal laminae produced in vivo on either side of myoid cells.


Endocrinology ◽  
2014 ◽  
Vol 155 (10) ◽  
pp. 3981-3995 ◽  
Author(s):  
N. Ece Gungor-Ordueri ◽  
Elizabeth I. Tang ◽  
Ciler Celik-Ozenci ◽  
C. Yan Cheng

Abstract During spermatogenesis, the transport of spermatids and the release of sperms at spermiation and the remodeling of the blood-testis barrier (BTB) in the seminiferous epithelium of rat testes require rapid reorganization of the actin-based cytoskeleton. However, the mechanism(s) and the regulatory molecule(s) remain unexplored. Herein we report findings that unfold the functional significance of ezrin in the organization of the testis-specific adherens junction at the spermatid-Sertoli cell interface called apical ectoplasmic specialization (ES) in the adluminal compartment and the Sertoli cell-cell interface known as basal ES at the BTB. Ezrin is expressed at the basal ES/BTB in all stages, except from late VIII to IX, of the epithelial cycle. Its knockdown by RNA interference (RNAi) in vitro perturbs the Sertoli cell tight junction-permeability barrier via a disruption of the actin microfilaments in Sertoli cells, which in turn impeded basal ES protein (eg, N-cadherin) distribution, perturbing the BTB function. These findings were confirmed by a knockdown study in vivo. However, the expression of ezrin at the apical ES is restricted to stage VIII of the cycle and limited only between step 19 spermatids and Sertoli cells. A knockdown of ezrin in vivo by RNAi was found to impede spermatid transport, causing defects in spermiation in which spermatids were embedded deep inside the epithelium, and associated with a loss of spermatid polarity. Also, ezrin was associated with residual bodies and phagosomes, and its knockdown by RNAi in the testis also impeded the transport of residual bodies/phagosomes from the apical to the basal compartment. In summary, ezrin is involved in regulating actin microfilament organization at the ES in rat testes.


2007 ◽  
Vol 292 (2) ◽  
pp. E513-E522 ◽  
Author(s):  
Andrii Domanskyi ◽  
Fu-Ping Zhang ◽  
Mirja Nurmio ◽  
Jorma J. Palvimo ◽  
Jorma Toppari ◽  
...  

Androgen receptor-interacting protein 4 (ARIP4) belongs to the SNF2 family of proteins involved in chromatin remodeling, DNA excision repair, and homologous recombination. It is a DNA-dependent ATPase, binds to DNA and mononucleosomes, and interacts with androgen receptor (AR) and modulates AR-dependent transactivation. We have examined in this study the expression and cellular localization of ARIP4 during postnatal development of mouse testis. ARIP4 was detected by immunohistochemistry in Sertoli cell nuclei at all ages studied, starting on day 5, and exhibited the highest expression level in adult mice. At the onset of spermatogenesis, ARIP4 expression became evident in spermatogonia, pachytene, and diplotene spermatocytes. Immunoreactive ARIP4 antigen was present in Leydig cell nuclei. In Sertoli cells ARIP4 was expressed in a stage-dependent manner, with high expression levels at stages II–VI and VII–VIII. ARIP4 expression patterns did not differ significantly in testes of wild-type, follicle-stimulating hormone receptor knockout, and luteinizing hormone receptor knockout mice. In testes of hypogonadal mice, ARIP4 was found mainly in interstitial cells and exhibited lower expression in Sertoli and germ cells. In vitro stimulation of rat seminiferous tubule segments with testosterone, FSH, or forskolin did not significantly change stage-specific levels of ARIP4 mRNA. Heterozygous ARIP4+/− mice were haploinsufficient and had reduced levels of Sertoli-cell specific androgen-regulated Rhox5 (also called Pem) mRNA. Collectively, ARIP4 is an AR coregulator in Sertoli cells in vivo, but the expression in the germ cells implies that it has also AR-independent functions in spermatogenesis.


2001 ◽  
Vol 12 (1) ◽  
pp. 85-100 ◽  
Author(s):  
Meredith Gonzales ◽  
Babette Weksler ◽  
Daisuke Tsuruta ◽  
Robert D. Goldman ◽  
Kristine J. Yoon ◽  
...  

The α4 laminin subunit is a component of endothelial cell basement membranes. An antibody (2A3) against the α4 laminin G domain stains focal contact-like structures in transformed and primary microvascular endothelial cells (TrHBMECs and HMVECs, respectively), provided the latter cells are activated with growth factors. The 2A3 antibody staining colocalizes with that generated by αv and β3 integrin antibodies and, consistent with this localization, TrHBMECs and HMVECs adhere to the α4 laminin subunit G domain in an αvβ3-integrin–dependent manner. The αvβ3 integrin/2A3 antibody positively stained focal contacts are recognized by vinculin antibodies as well as by antibodies against plectin. Unusually, vimentin intermediate filaments, in addition to microfilament bundles, interact with many of the αvβ3 integrin-positive focal contacts. We have investigated the function of α4-laminin and αvβ3-integrin, which are at the core of these focal contacts, in cultured endothelial cells. Antibodies against these proteins inhibit branching morphogenesis of TrHBMECs and HMVECs in vitro, as well as their ability to repopulate in vitro wounds. Thus, we have characterized an endothelial cell matrix adhesion, which shows complex cytoskeletal interactions and whose assembly is regulated by growth factors. Our data indicate that this adhesion structure may play a role in angiogenesis.


2005 ◽  
Vol 288 (3) ◽  
pp. E502-E509 ◽  
Author(s):  
Melanie J. Luther ◽  
Emma Davies ◽  
Dany Muller ◽  
Moira Harrison ◽  
Adrian J. Bone ◽  
...  

Cell-to-cell interactions play an important role in the development and maintenance of the β-cell phenotype. Here, we have investigated whether E-cadherin plays a role in regulating the growth of insulin-secreting MIN6 cells configured as three-dimensional islet-like clusters (pseudoislets). Pseudoislets form by cell aggregation rather than by proliferation from individual cells and attain the size of primary mouse islets after ∼7 days of maintenance in culture. E-cadherin is known to mediate homotypic cell adhesion between β-cells and has also been implicated in a number of cellular processes, including proliferation, apoptosis, and differentiation. E-cadherin and its associated intracellular elements, α- and β-catenin, were upregulated in MIN6 pseudoislets. Pseudoislet formation was associated with an increased expression of cyclin-dependent kinase inhibitors and a concomitant downregulation of Ki67, suggesting an overall reduction in cellular proliferation. However, measurements of 5-bromo-2′-deoxyuridine incorporation revealed that there were no differences in the rate of MIN6 cell proliferation whether they were configured as monolayers or as pseudoislets, which is likely to be a result of their being a transformed cell line. Cells within pseudoislets were not necrotic, but apoptosis appeared to be upregulated in the islet-like structures. However, no differential expression of Fas and FasL was detected in monolayers and pseudoislets. These results suggest that cell-to-cell interactions within islet-like structures may initiate antiproliferative and proapoptotic signals.


Author(s):  
Yu Takahashi ◽  
Yu Inoue ◽  
Keitaro Kuze ◽  
Shintaro Sato ◽  
Makoto Shimizu ◽  
...  

Abstract Intestinal organoids better represent in vivo intestinal properties than conventionally used established cell lines in vitro. However, they are maintained in three-dimensional culture conditions that may be accompanied by handling complexities. We characterized the properties of human organoid-derived two-dimensionally cultured intestinal epithelial cells (IECs) compared with those of their parental organoids. We found that the expression of several intestinal markers and functional genes were indistinguishable between monolayer IECs and organoids. We further confirmed that their specific ligands equally activate intestinal ligand-activated transcriptional regulators in a dose-dependent manner. The results suggest that culture conditions do not significantly influence the fundamental properties of monolayer IECs originating from organoids, at least from the perspective of gene expression regulation. This will enable their use as novel biological tools to investigate the physiological functions of the human intestine.


1999 ◽  
Vol 340 (1) ◽  
pp. 309-320 ◽  
Author(s):  
Sikha Bettina MUKHERJEE ◽  
S. ARAVINDA ◽  
B. GOPALAKRISHNAN ◽  
Sushma NAGPAL ◽  
Dinakar M. SALUNKE ◽  
...  

The seminiferous tubular fluid (STF) provides the microenvironment necessary for spermatogenesis in the adluminal compartment of the seminiferous tubule (ST), primarily through secretions of the Sertoli cell. Earlier studies from this laboratory demonstrated the presence of glutathione S-transferase (GST) in STF collected from adult rat testis and in the spent media of ST cultures. This study describes the cellular source, isoform composition and possible function of GSTs in the STF. The major GST isoforms present in STF in vivo share extensive N-terminal similarity with rat GSTM1 (rGSTM1), rGSTM2, rGSTM3 and rGST-Alpha. Molecular masses of rGSTM2, rGSTM3 and rGST-Alpha from liver and testis sources were similar, unlike STF-GSTM1, which was larger by 325 Da than its liver counterpart. Peptide digest analysis profiles on reverse-phase HPLC between liver and STF isoforms were identical, and N-terminal sequences of selected peptides obtained by digestion of the various isoforms were closely similar. The above results confirmed close structural similarity between liver and STF-GST isoforms. Active synthesis and secretion of GSTs by the STs were evident from recovery of radiolabelled GST from the spent media of ST cultures. Analysis of secreted GST isoforms showed that GST-Alpha was not secreted by the STs in vitro, whereas there was an induction of GST-Pi secretion. Detection of immunostainable GST-Mu in Sertoli cells in vitro and during different stages of the seminiferous epithelium in vivo, coupled with the recovery of radiolabelled GST from Sertoli cell-culture media, provided evidence for Sertoli cells as secretors of GST. In addition, STF of ‘Sertoli cell only’ animals showed no change in the profile of GST isoform secretion, thereby confirming Sertoli cells as prime GST secretors. Non-recovery of [35S]methionine-labelled GSTs from germ cell culture supernatants, but their presence in germ cell lysates, confirm the ability of the germ cells to synthesize, but not to release, GSTs. Functionally, STF-GSTM1 appeared to serve as a steroid-binding protein by its ability to bind to testosterone and oestradiol, two important hormones in the ST that are essential for spermatogenesis, with binding constants of < 9.8×10-7 M for testosterone and 9×10-6 M for oestradiol respectively.


2010 ◽  
Vol 22 (9) ◽  
pp. 66
Author(s):  
P. K. Nicholls ◽  
P. G. Stanton ◽  
K. L. Walton ◽  
R. I. McLachlan ◽  
L. O'Donnell ◽  
...  

Spermatogenesis is absolutely dependent on follicle stimulating hormone (FSH) and androgens; acute suppression of these hormones inhibits germ cell development and thus sperm production. The removal of intercellular junctions and release of spermatids by the Sertoli cell, a process known as spermiation, is particularly sensitive to acute hormone suppression(1). To define the molecular mechanisms that mediate FSH and androgen effects in the testis, we investigated the expression and hormonal regulation of micro-RNAs (miRNA), small non-coding RNAs that regulate protein translation and modify cellular responses. By array analysis, we identified 23 miRNAs that were upregulated >2-fold in stage VIII seminiferous tubules following hormone suppression, and in vitro in primary Sertoli cells. We subsequently validated the expression and hormonal regulation of several miRNAs, including miR-23b, -30d and -690 by quantitative PCR in primary Sertoli cells. Bioinformatic analysis of potential targets of hormonally-suppressed miRNAs identified genes associated with Focal adhesions (54 genes, P = –ln(17.97)) and the Regulation of the actin cytoskeleton (52 genes, P = –ln(10.16)), processes known to be intimately associated with adhesion of spermatids to Sertoli cells(2, 3). Furthermore, this analysis identified numerous components of the testicular tubulobulbar complex (TBC) as being targets of hormonally sensitive miRNAs. The TBC is a podosome-like structure between Sertoli and adjacent spermatids in the testis, which internalises intact inter-cellular junctions by endocytotic mechanisms prior to spermiation(4). We then demonstrate the hormonal regulation of predicted miRNA target proteins, and validate novel inhibitory miRNA interactions with Pten, nWASP, Eps15 and Picalm by luciferase knockdown in vitro. We hypothesise that hormonally suppressed miRNAs inhibit TBC function, and subsequently, endocytosis of intercellular junctions. In conclusion, we have demonstrated that hormonal suppression in the testis stimulates the expression of a subset of Sertoli cell miRNAs that are likely regulators of cell adhesion protein networks involved in spermiation. (1) Saito K, O’Donnell L, McLachlan RI, Robertson DM 2000 Spermiation failure is a major contributor to early spermatogenic suppression caused by hormone withdrawal in adult rats. Endocrinology 141: 2779–2.(2) O’Donnell L, Stanton PG, Bartles JR, Robertson DM 2000 Sertoli cell ectoplasmic specializations in the seminiferous epithelium of the testosterone-suppressed adult rat. Biol Reprod 63: 99–108.(3) Beardsley A, Robertson DM, O’Donnell L 2006 A complex containing alpha6beta1-integrin and phosphorylated focal adhesion kinase between Sertoli cells and elongated spermatids during spermatid release from the seminiferous epithelium. J Endocrinol 190(3): 759–70.(4) Young JS, Guttman JA, Vaid KS, Vogl AW 2009 Tubulobulbar complexes are intercellular podosome-like structures that internalize intact intercellular junctions during epithelial remodeling events in the rat testis. Biol Reprod 80: 162–74.


1991 ◽  
Vol 70 (5) ◽  
pp. 2259-2267 ◽  
Author(s):  
M. Somerville ◽  
P. S. Richardson ◽  
A. Rutman ◽  
R. Wilson ◽  
P. J. Cole

We have investigated the effect of elastase and alkaline protease from Pseudomonas aeruginosa on airway secretion into the trachea of anesthetized cats and from human bronchial mucosa in vitro. Secretory macromolecules were radiolabeled biosynthetically with two precursors in the cat, [3H]glucose and [35S]sulfate, and with [35S]-sulfate only in human tissue. Both enzymes (2.6 x 10(-9) to 1.3 x 10(-6)M elastase and 8 x 10(-9) to 2.4 x 10(-6)M alkaline protease) released radiolabeled macromolecules in a concentration-dependent manner from the two preparations. Purified elastase, 1.3 x 10(-6)M, released radiolabeled macromolecules (delta 3H = +397 +/- 72%, delta 35S 225 +/- 40% over control, P less than 0.001) and periodic acid-Schiff- (PAS) reactive glycoconjugates (delta PAS = +4.1 +/- 0.96 micrograms/min or +102 +/- 20%; P less than 0.01) from cat trachea, as did alkaline protease, 2.4 x 10(-6)M (delta 3H = +356 +/- 57%, delta 35S = +176 +/- 25%, delta PAS = +7.5 +/- 1.3 micrograms/min or 194 +/- 36%, P less than 0.001). Increases in 3H exceeded those of 35S, suggesting surface epithelium as the main source of secretion. Inhibition of enzyme activity abolished secretory effects. Both enzymes also stimulated secretion from human bronchus (e.g., with elastase, 1.3 x 10(-6)M: delta 35S = +331 +/- 67%, delta PAS = +4.3 +/- 0.92 micrograms/min or +131 +/- 24%, P less than 0.001; with alkaline protease, 2.4 x 10(-6)M: delta 35S = +220 +/- 67%, delta PAS = +12.7 +/- 3.2 micrograms/min or +575 +/- 245%, P less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)


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