scholarly journals c-Yes regulates cell adhesion at the apical ectoplasmic specialization-blood-testis barrier axis via its effects on protein recruitment and distribution

2013 ◽  
Vol 304 (2) ◽  
pp. E145-E159 ◽  
Author(s):  
Xiang Xiao ◽  
Dolores D. Mruk ◽  
C. Yan Cheng

During spermatogenesis, extensive restructuring takes place at the cell-cell interface since developing germ cells migrate progressively from the basal to the adluminal compartment of the seminiferous epithelium. Since germ cells per se are not motile cells, their movement relies almost exclusively on the Sertoli cell. Nonetheless, extensive exchanges in signaling take place between these cells in the seminiferous epithelium. c-Yes, a nonreceptor protein tyrosine kinase belonging to the Src family kinases (SFKs) and a crucial signaling protein, was recently shown to be upregulated at the Sertoli cell-cell interface at the blood-testis barrier (BTB) at stages VIII–IX of the seminiferous epithelial cycle of spermatogenesis. It was also highly expressed at the Sertoli cell-spermatid interface known as apical ectoplasmic specialization (apical ES) at stage V to early stage VIII of the epithelial cycle during spermiogenesis. Herein, it was shown that the knockdown of c-Yes by RNAi in vitro and in vivo affected both Sertoli cell adhesion at the BTB and spermatid adhesion at the apical ES, causing a disruption of the Sertoli cell tight junction-permeability barrier function, germ cell loss from the seminiferous epithelium, and also a loss of spermatid polarity. These effects were shown to be mediated by changes in distribution and/or localization of adhesion proteins at the BTB (e.g., occludin, N-cadherin) and at the apical ES (e.g., nectin-3) and possibly the result of changes in the underlying actin filaments at the BTB and the apical ES. These findings implicate that c-Yes is a likely target of male contraceptive research.

1998 ◽  
Vol 4 (S2) ◽  
pp. 1068-1069
Author(s):  
Ann-Marie Broome ◽  
Clarke F. Millette

Cell adhesion and cell adhesion molecules (CAMs) play a crucial role in testicular development and function. The seminiferous epithelium, the functional unit of the testis, represents a three dimensional architecture of supporting Sertoli cells (SC), and developing germ cells (GC). The seminiferous epithelium, therefore, must be receptive not only to individual cell growth and differentiation, but also to cell-cell interactions. Morphologically distinct cell-cell interactions occur between SC and GC and also between SC.[1] In general, these junctions can be categorized into three types: adhesive, occluding, and gap junctions. The orientation and function of these junctions are interaction dependent. For example, desmosome-like junctions (spot desmosomes) are found between SC and GC. These junctions are present in the basal and intermediate compartments of the testis and serve to translocate developing GC. SC-SC interactions, like the zonula occludens (tight junction), function as vectorial mediators, maintaining the blood-testis barrier and SC polarity.


Author(s):  
Rachel L Gewiss ◽  
Nathan C Law ◽  
Aileen R Helsel ◽  
Eric A Shelden ◽  
Michael D Griswold

Abstract Sertoli cells are a critical component of the testis environment for their role in maintaining seminiferous tubule structure, establishing the blood-testis barrier, and nourishing maturing germ cells in a specialized niche. This study sought to uncover how Sertoli cells are regulated in the testis environment via germ cell crosstalk in the mouse. We found two major clusters of Sertoli cells as defined by their transcriptomes in Stages VII–VIII of the seminiferous epithelium and a cluster for all other stages. Additionally, we examined transcriptomes of germ cell-deficient testes and found that these existed in a state independent of either of the germ cell-sufficient clusters. Altogether, we highlight two main transcriptional states of Sertoli cells in an unperturbed testis environment, and a germ cell-deficient environment does not allow normal Sertoli cell transcriptome cycling and results in a state unique from either of those seen in Sertoli cells from a germ cell-sufficient environment.


2014 ◽  
Vol 307 (9) ◽  
pp. E738-E753 ◽  
Author(s):  
N. Ece Gungor-Ordueri ◽  
Ciler Celik-Ozenci ◽  
C. Yan Cheng

In the testis, spermatids are polarized cells, with their heads pointing toward the basement membrane during maturation. This polarity is crucial to pack the maximal number of spermatids in the seminiferous epithelium so that millions of sperms can be produced daily. A loss of spermatid polarity is detected after rodents are exposed to toxicants (e.g., cadmium) or nonhormonal male contraceptives (e.g., adjudin), which is associated with a disruption on the expression and/or localization of polarity proteins. In the rat testis, fascin 1, an actin-bundling protein found in mammalian cells, was expressed by Sertoli and germ cells. Fascin 1 was a component of the ectoplasmic specialization (ES), a testis-specific anchoring junction known to confer spermatid adhesion and polarity. Its expression in the seminiferous epithelium was stage specific. Fascin 1 was localized to the basal ES at the Sertoli cell-cell interface of the blood-testis barrier in all stages of the epithelial cycle, except it diminished considerably at late stage VIII. Fascin 1 was highly expressed at the apical ES at stage VII–early stage VIII and restricted to the step 19 spermatids. Its knockdown by RNAi that silenced fascin 1 by ∼70% in Sertoli cells cultured in vitro was found to perturb the tight junction-permeability barrier via a disruption of F-actin organization. Knockdown of fascin 1 in vivo by ∼60–70% induced defects in spermatid polarity, which was mediated by a mislocalization and/or downregulation of actin-bundling proteins Eps8 and palladin, thereby impeding F-actin organization and disrupting spermatid polarity. In summary, these findings provide insightful information on spermatid polarity regulation.


Endocrinology ◽  
2009 ◽  
Vol 150 (10) ◽  
pp. 4724-4733 ◽  
Author(s):  
Ilona A. Kopera ◽  
Linlin Su ◽  
Barbara Bilińska ◽  
C. Yan Cheng ◽  
Dolores D. Mruk

Abstract Adjudin is known to specifically affect Sertoli-germ cell adhesion, resulting in germ cell loss from the seminiferous epithelium and transient infertility. The apical ectoplasmic specialization (ES) was shown to be the primary target of adjudin because adhesion was unaffected in organs that lack this structure. Herein we expand previous findings by treating rat pups with adjudin, and we aimed to address two questions. First, can adjudin perturb germ cell adhesion in the seminiferous epithelium of testes in which the apical ES is not yet present? Second, can adjudin affect assembly of the blood-testis barrier (BTB) at 15–18 d of age? Interesting changes were noted when aged-matched testes from control and adjudin-treated rats were examined, including a delay in the appearance of developing germ cells as well as a delay in the formation of the tubule lumen. Immunoblotting using antibodies against BTB-constituent proteins indicated that formation of the BTB was affected in rat pups gavaged with adjudin. These results were corroborated by immunofluorescence microscopy, which showed profound changes in the cellular distribution of tight junction and basal ES proteins. Moreover, the BTB was shown to be compromised in 30-d-old rats when its integrity was assessed by a functional in vivo assay. By 45 d of age, however, the seminiferous epithelium of treated rats was indistinguishable from that of control rats. Collectively these results demonstrate that adjudin targets the apical ES as well as the basal ES and tight junction, which in turn delays assembly of the BTB.


Endocrinology ◽  
2009 ◽  
Vol 150 (7) ◽  
pp. 3336-3344 ◽  
Author(s):  
Erica R. Siu ◽  
Elissa W. P. Wong ◽  
Dolores D. Mruk ◽  
K. L. Sze ◽  
Catarina S. Porto ◽  
...  

Several integral membrane proteins that constitute the blood-testis barrier (BTB) in mammalian testes, in particular rodents, are known to date. These include tight junction (TJ) proteins (e.g. occludin, junctional adhesion molecule-A, claudins), basal ectoplasmic specialization proteins (e.g. N-cadherin), and gap junction proteins (e.g. connexin43). However, the regulators (e.g. protein kinases and phosphatases) that affect these proteins, such as their interaction with the cytoskeletal actin, which in turn confer cell adhesion at the TJ, remain largely unknown. We report herein that focal adhesion kinase (FAK) is a putative interacting partner of occludin, but not claudin-11 or junctional adhesion molecule-A. Immunohistochemistry and fluorescence microscopy studies illustrated that the expression of FAK in the seminiferous epithelium of adult rat testes was stage specific. FAK colocalized with occludin at the BTB in virtually all stages of the seminiferous epithelial cycle but considerably diminished in stages VIII–IX, at the time of BTB restructuring to facilitate the transit of primary leptotene spermatocytes. Using Sertoli cells cultured in vitro with established TJ-permeability barrier and ultrastructures of TJ, basal ectoplasmic specialization and desmosome-like junction that mimicked the BTB in vivo, FAK was shown to colocalize with occludin and zonula occludens-1 (ZO-1) at the Sertoli-Sertoli cell interface. When these Sertoli cell cultures were treated with CdCl2 to perturb the TJ-barrier function, occludin underwent endocytic-mediated internalization in parallel with FAK and ZO-1. Thus, these findings demonstrate that FAK is an integrated regulatory component of the occludin-ZO-1 protein complex, suggesting that functional studies can be performed to study the role of FAK in BTB dynamics.


Endocrinology ◽  
2009 ◽  
Vol 150 (10) ◽  
pp. 4713-4723 ◽  
Author(s):  
Elissa W. P. Wong ◽  
Shengyi Sun ◽  
Michelle W. M. Li ◽  
Will M. Lee ◽  
C. Yan Cheng

Abstract Polarity proteins have been implicated in regulating and maintaining tight junction (TJ) and cell polarity in epithelia. Here we report 14-3-3θ, the homolog of Caenorhabditis elegans Par5 in mammalian cells, which is known to confer cell polarity at TJ, is found at the apical ectoplasmic specialization (ES), a testis-specific adherens junction type restricted to the Sertoli cell-elongating spermatid interface, in which TJ is absent. 14-3-3θ was shown to play a critical role in conferring cell adhesion at the apical ES. A loss of 14-3-3θ expression at the apical ES was detected in the seminiferous epithelium before spermiation. Involvement of 14-3-3θ in Sertoli cell adhesion was confirmed by its knockdown by RNA interference in Sertoli cells cultured in vitro with established TJ permeability barrier that mimicked the blood-testis barrier (BTB) in vivo. Mislocalization of N-cadherin and zonula occludens-1, but not α- and β-catenins, was observed after 14-3-3θ knockdown in Sertoli cells, moving from the cell-cell interface to cytosol, indicating a disruption of cell adhesion. Studies by endocytosis assay illustrated that this loss of cell adhesion was mediated by an increase in the kinetics of endocytosis of N-cadherin and junctional adhesion molecule-A at the BTB, which may represent a general mechanism by which polarity proteins regulate cell adhesion. In summary, the testis is using 14-3-3θ to regulate cell adhesion at the apical ES to facilitate spermiation and at the BTB to facilitate the transit of preleptotene spermatocytes at stages VIII–IX of the epithelial cycle. 14-3-3θ may act as a molecular switch that coordinates these two cellular events in the seminiferous epithelium during spermatogenesis.


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.


F1000Research ◽  
2018 ◽  
Vol 7 ◽  
pp. 1544 ◽  
Author(s):  
Vivian W. Tang

The epithelial lateral membrane plays a central role in the integration of intercellular signals and, by doing so, is a principal determinant in the emerging properties of epithelial tissues. Mechanical force, when applied to the lateral cell–cell interface, can modulate the strength of adhesion and influence intercellular dynamics. Yet the relationship between mechanical force and epithelial cell behavior is complex and not completely understood. This commentary aims to provide an investigative look at the usage of cellular forces at the epithelial cell–cell adhesion interface.


2011 ◽  
Vol 209 (3) ◽  
pp. 337-351 ◽  
Author(s):  
Linlin Su ◽  
Dolores D Mruk ◽  
Will M Lee ◽  
C Yan Cheng

The blood–testis barrier (BTB) creates an immunological barrier that segregates the seminiferous epithelium into the basal and apical compartment. Thus, meiosis I/II and post-meiotic germ cell development take place in a specialized microenvironment in the apical compartment behind the BTB and these events are being shielded from the host immune system. If unwanted drugs and/or chemicals enter the apical compartment from the microvessels in the interstitium via the basal compartment, efflux pumps (e.g. P-glycoprotein) located in Sertoli cells and/or spermatids can actively transport these molecules out of the apical compartment. However, the mechanism(s) by which influx pumps regulate the entry of drugs/chemicals into the apical compartment is not known. In this study, a solute carrier (SLC) transporter organic anion transporting polypeptide 3 (Oatp3, Slco1a5) was shown to be an integrated component of the N-cadherin-based adhesion complex at the BTB. However, a knockdown of Oatp3 alone or in combination with three other major Sertoli cell drug influx pumps, namely Slc22a5, Slco6b1, and Slco6c1, by RNAi using corresponding specific siRNA duplexes failed to perturb the Sertoli cell tight junction (TJ) permeability barrier function. Yet, the transport of [3H]adjudin, a potential male contraceptive that is considered a toxicant to spermatogenesis, across the BTB was impeded following the knockdown of either Oatp3 or all the four SLC transporters. In short, even though drug transporters (e.g. influx pumps) are integrated components of the adhesion protein complexes at the BTB, they are not involved in regulating the Sertoli cell TJ permeability barrier function, instead they are only involved in the transport of drugs, such as adjudin, across the immunological barrier at the BTB.


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