The blood‐testis barrier and sertoli cell junctions: Structural considerations

Pelletier, R.‐Marc; Byers, Stephen W.

doi:10.1002/jemt.1070200104

Cited by 153 publications

(115 citation statements)

References 210 publications

(268 reference statements)

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“…Cx43-mediated heterocellular contacts between Sertoli and germinal cells is consistent with recent findings of Cx43 gene transcript in germinal and Sertoli cells by in situ hybridization (Batias et al, 2000). It is also consistent with the description of dye transfer (Batias et al, 2000;Orth and Boehm, 1990) and gap junctions (Byers and Pelletier, 1991;McGinley et al, 1979) between Sertoli and germinal cells, and between adjacent germinal cells (Pelletier and Byers, 1992). Further studies using electron microscopic techniques will confirm whether Cx43-mediated heterocellular contacts exist between SC cells.…”

Section: Bsupporting

confidence: 88%

Expression of Connexin43 in mouse Leydig, Sertoli, and germinal cells at different stages of postnatal development

et al. 2001

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Connexin 43 (Cx43) is the most abundant and ubiquitously distributed gap junction protein in testicular cells. Lack of Cx43 expression results in male infertility. We investigated whether Cx43 is expressed and regulated in Leydig, Sertoli and germinal cells at different stages of postnatal development. Cx43 was detected using three different antibodies shown by immunoblotting to be highly specific. At different postnatal ages Cx43 localization was compared in serial or double labeled testicular cryosections with immunocytochemical distribution of steroidogenic enzyme, 3 ␤hidroxysteroid-dehydrogenase (3␤HSD), Mullerian inhibitory hormone (MIH), and germinal nuclear cell antigen (GNCA1), which are specific markers of interstitial Leydig, Sertoli and germinal cells, respectively. In the interstitium, round cell clumps (RCC) with lipid droplets positive for 3␤HSD and Cx43 were frequently found at intertubular areas at birth and Cx43 was mainly localized at cell membrane appositions. From day 3, the number and size of 3␤HSD-positive RCC started to decrease, and reached a minimum at 7-14 dpp; Cx43 expressed by them is progressively downregulated. From day 21 an increase in the size and number of RCC positive for Cx43 and 3␤HSD was found that continued at 24, 26 and 28 days and reached a maximum at 35 and 60 dpp. Biphasic expression of interstitial Cx43 and 3␤HSD was also found to be positively and temporally correlated with fluctuations in intratesticular testosterone content at all ages studied. In the seminiferous cord (SC), Cx43 was expressed at birth between adjacent Sertoli cells (MIH positive) localized at the periphery, as well as in their cytoplasm projections that surround centrally localized gonocytes. From days 3 to 7, Cx43 labeling increased in Sertoli cells mainly at their apical border. At day 14, Cx43 distribution in Sertoli cells changed from apical to basal in parallel to migration of germinal (GNCA1-positive) cells from the periphery to the center of the SC. At all these ages, Cx43 was also localized at cell borders between Sertoli and germinal cells. In conclusion, this study demonstrates that Cx43 in Leydig cells is regulated during postnatal development in an age and functional dependent manner. In the tubule, it is demonstrated that Cx43 is modulated in Sertoli cells during the neonatal and prepubertal period. We also provide evidence for the first time that Cx43-gap junctions communicate between Sertoli and germinal cells before and during the first wave of spermatogenesis. Anat Rec 264: [13][14][15][16][17][18][19][20][21][22][23][24] 2001.

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Section: Bsupporting

confidence: 88%

Expression of Connexin43 in mouse Leydig, Sertoli, and germinal cells at different stages of postnatal development

et al. 2001

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“…Although Sertoli cells extend from the basal compartment into the adluminal compartment, the two tubular compartments are separated by junctional complexes (tight and adherens junctions) between neighbouring Sertoli cells, that function as the major component of the blood-testis barrier Dym & Fawcett, 1971;Russell, 1977;Holash et al, 1993;Li et al, 2006). This barrier, dividing the seminiferous epithelium, selectively restricts the passage of many substances contained in the general circulation (Dym, 1973, Pelletier & Byers, 1992Kato et al, 2005;Li et al, 2006). The integrity of the bloodtestis barrier is a prerequisite for normal spermatogenesis.…”

Section: Compartmentalization and The Blood-testis Barriermentioning

confidence: 99%

“…As well as tight junctions, gap junctions are also present in the blood-testis barrier as shown by ultrastructural analysis in rats (Dym & Fawcett, 1970;Gilula et al, 1976;Batias et al, 2000). The blood-testis barrier sequesters germ cells usually considered antigenic, protecting the differentiated germ cells from the autoimmune response (Pelletier & Byers, 1992;Willing et al, 1998;Hemendinger et al, 2002) and from exposure to many compounds found in blood or interstitial tissue fluid which can be harmful to germ cells (Waites & Glawell, 1982;Bart et al, 2004;Augustine et al, 2005). The unique components of the tubular fluid in the adluminal compartment formed by Sertoli-Sertoli tight junctions create the necessary chemical microenvironment for completion of meiosis and spermiogenesis (Fenton et al, 2002;Xia et al, 2006).…”

Section: Compartmentalization and The Blood-testis Barriermentioning

confidence: 99%

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Vitamin C and oxidative stress in the seminiferous epithelium

et al. 2011

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In this article, we focus on the fundamental role of vitamin C transporters for the normal delivery of vitamin C to germ cells in the adluminal compartment of seminiferous tubules. We argue that the redox status within spermatozoa or in semen is partly responsible for the etiology of infertility. In this context, antioxidant defence plays a critical role in male fertility. Vitamin C, a micronutrient required for a wide variety of metabolic functions, has long been associated with male reproduction. Two systems for vitamin C transport have been described in mammals. Facilitative hexose transporters (GLUTs), with 14 known isoforms to date, GLUT1-GLUT14, transport the oxidized form of vitamin C (dehydroascorbic acid) into the cells. Sodium ascorbic acid co-transporters (SVCTs), SVCT1 and SVCT2 transport the reduced form of vitamin C (ascorbic acid). Sertoli cells control germ cell proliferation and differentiation through cell-cell communication and form the blood-testis barrier. Because the blood-testis barrier limits direct access of molecules from the plasma into the adluminal compartment of the seminiferous tubule, one important question is the method by which germ cells obtain vitamin C. Some interesting results have thrown light on this matter. Expression of SVCT2 and some isoforms of GLUT transporters in the testis have previously been described. Our group has demonstrated that Sertoli cells express functionally active vitamin C transporters. Kinetic characteristics were described for both transport systems (SVCT and GLUT systems). Sertoli cells are able to transport both forms of vitamin C. These fi ndings are extremely relevant, because Sertoli cells may control the amount of vitamin C in the adluminal compartment, as well as regulating the availability of this metabolite throughout spermatogenesis.

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“…[3][4][5][6], the BTB is composed of coexisting TJs, AJs, and desmosome-like junctions (for reviews, see refs. [7][8][9]. One of the main roles of the TJ barrier is to prevent small molecules from passing through the paracellular space.…”

mentioning

confidence: 99%

Blood–testis barrier dynamics are regulated by an engagement/disengagement mechanism between tight and adherens junctions via peripheral adaptors

Yan

Cheng

2005

Proc. Natl. Acad. Sci. U.S.A.

102

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In the mammalian testis, the blood-testis barrier (BTB), unlike the blood-brain and blood-retina barriers, is composed of coexisting tight junctions (TJs) and adherens junctions (AJs). Yet these junctions must open (or disassemble) to accommodate the migration of preleptotene and leptotene spermatocytes across the BTB during spermatogenesis while maintaining its integrity. In this report, we show that the BTB utilizes a unique ''engagement'' and ''disengagement'' mechanism to permit the disruption of AJ that facilitates germ cell movement without compromising the BTB integrity. For instance, both TJ (e.g., occludin and JAM-1) and AJ (e.g., N-cadherin) integral membrane proteins were colocalized to the same site at the BTB. Although these TJ-and AJ-integral membrane proteins did not physically interact with each other, they were structurally linked by means of peripheral adaptors (e.g., ZO-1 and ␣-and ␥-catenins). As such, these proteins are structurally ''engaged'' under physiological conditions to reinforce the BTB. When rats were exposed to Adjudin to induce AJ restructuring that eventually led to germ cell loss from the epithelium, this structural interaction between occludin and N-cadherin by means of their adaptors became ''disengaged'' while their protein levels were significantly induced. In short, when the epithelium is under assault, such as by Adjudin or plausibly at the time of germ cell migration across the BTB during spermatogenesis, the TJ-and AJ-integral membrane proteins can be disengaged. Thus, this mechanism is used by the testis to facilitate AJ restructuring to accommodate germ cell migration while maintaining the BTB integrity.spermatogenesis ͉ ectoplasmic specialization ͉ Sertoli-germ cell interaction D uring spermatogenesis, preleptotene and leptotene spermatocytes that are residing outside the blood-testis barrier (BTB) in the basal compartment of the seminiferous epithelium traverse the BTB at stages VIII-IX of the epithelial cycle in mammalian testes, such as those of the rat (1). As such, extensive restructuring of tight junctions (TJs), adherens junctions (AJs), and desmosomelike junctions must take place in the epithelium to facilitate germ cell movement (for a review, see ref.2). Interestingly, unlike barriers in other mammalian organs, such as the blood-brain, blood-retina, and blood-epididymal barriers, where TJ is restricted to the apical portion of the cell epithelium and͞or endothelium, to be followed by AJ (for reviews, see refs. 3-6), the BTB is composed of coexisting TJs, AJs, and desmosome-like junctions (for reviews, see refs. 7-9). One of the main roles of the TJ barrier is to prevent small molecules from passing through the paracellular space. The endothelial TJ barrier in blood vessels, for example, is only opened occasionally to allow the passage of neutrophils and macrophages during inflammation (for a review, see ref. 10). However, in the testis, the BTB is a highly dynamic structure because it must open (or disassemble) periodically to accommodate the migration of g...

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The blood‐testis barrier and sertoli cell junctions: Structural considerations

Cited by 153 publications

References 210 publications

Expression of Connexin43 in mouse Leydig, Sertoli, and germinal cells at different stages of postnatal development

Expression of Connexin43 in mouse Leydig, Sertoli, and germinal cells at different stages of postnatal development

Vitamin C and oxidative stress in the seminiferous epithelium

Blood–testis barrier dynamics are regulated by an engagement/disengagement mechanism between tight and adherens junctions via peripheral adaptors

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