scholarly journals Androgen-Dependent Sertoli Cell Tight Junction Remodeling Is Mediated by Multiple Tight Junction Components

2014 ◽  
Vol 28 (7) ◽  
pp. 1055-1072 ◽  
Author(s):  
Papia Chakraborty ◽  
F. William Buaas ◽  
Manju Sharma ◽  
Benjamin E. Smith ◽  
Anne R. Greenlee ◽  
...  
Keyword(s):  
Androgen Receptor ◽  
Tight Junction ◽  
Tight Junctions ◽  
Sertoli Cell ◽  
Chromatin Immunoprecipitation ◽  
Target Genes ◽  
Altered Expression ◽  
Junction Protein ◽  
Epithelial Compartment ◽  
Androgen Regulation

Sertoli cell tight junctions (SCTJs) of the seminiferous epithelium create a specialized microenvironment in the testis to aid differentiation of spermatocytes and spermatids from spermatogonial stem cells. SCTJs must be chronically broken and rebuilt with high fidelity to allow the transmigration of preleptotene spermatocytes from the basal to adluminal epithelial compartment. Impairment of androgen signaling in Sertoli cells perturbs SCTJ remodeling. Claudin (CLDN) 3, a tight junction component under androgen regulation, localizes to newly forming SCTJs and is absent in Sertoli cell androgen receptor knockout (SCARKO) mice. We show here that Cldn3-null mice do not phenocopy SCARKO mice: Cldn3−/− mice are fertile, show uninterrupted spermatogenesis, and exhibit fully functional SCTJs based on imaging and small molecule tracer analyses, suggesting that other androgen-regulated genes must contribute to the SCARKO phenotype. To further investigate the SCTJ phenotype observed in SCARKO mutants, we generated a new SCARKO model and extensively analyzed the expression of other tight junction components. In addition to Cldn3, we identified altered expression of several other SCTJ molecules, including down-regulation of Cldn13 and a noncanonical tight junction protein 2 isoform (Tjp2iso3). Chromatin immunoprecipitation was used to demonstrate direct androgen receptor binding to regions of these target genes. Furthermore, we demonstrated that CLDN13 is a constituent of SCTJs and that TJP2iso3 colocalizes with tricellulin, a constituent of tricellular junctions, underscoring the importance of androgen signaling in the regulation of both bicellular and tricellular Sertoli cell tight junctions.

GENETIC SUSCEPTIBILITY TO IBD OPERATES VIA CONTROL OF APICAL JUNCTIONAL COMPLEXES

2021 ◽  
Vol 27 (Supplement_1) ◽  
pp. S30-S30
Author(s):  
Isabelle Hébert-Milette ◽  
Chloé Lévesque ◽  
Guy Charron ◽  
John Rioux
Keyword(s):  
Tight Junction ◽  
Tight Junctions ◽  
Intestinal Inflammation ◽  
Protein Localization ◽  
Junctional Complex ◽  
Epithelial Permeability ◽  
3D Cultures ◽  
Apical Junctional Complex ◽  
Junction Protein ◽  
The Impact

Abstract Introduction Intestinal permeability is increased in unaffected 1st degree relatives of patients with inflammatory bowel disease (IBD), and is considered a risk factor for the development of IBD, likely increasing the interactions between intestinal microorganisms and the immune system. We recently reported that C1orf106, a gene located within a genomic region associated with IBD, regulates epithelial permeability. We further demonstrated that a rare coding variant within C1orf106 (p.Y333F) decreases protein stability and that lower levels of C1orf106 protein leads altered stability of adherens junctions (AJ) and to an increase in epithelial permeability. Hypothesis In addition to altering AJ, we believe that C1orf106 is also involved in the regulation of tight junction (TJ) formation, which also impacts epithelial permeability. Objectives The objectives of the project are to (a) validate the impact of C1orf106 on tight junctions and (b) verify the impact of C1orf106 IBD-associated variants on intestinal barrier integrity. Results We observed that knocking down the expression of C1orf106 in Caco-2 cells leads to a number of phenotypes in human epithelial monolayer (2D) and spheroid (3D) cultures that are associated with alterations in TJs. Specifically, when studying the dynamic reformation of TJ in 2D cultures after transient withdrawal of calcium, which is required for TJ stability, we observed that lower levels of C1orf106 resulted in (1) decreased recovery of barrier function as measured by transepithelial electrical resistance (TEER); (2) an alteration of tight junction protein localization; and (3) thickening of the circumferential actin belt. Moreover, in 3D cultures, we observed an altered spheroid formation associated with impaired epithelial polarization. In addition, our preliminary studies of human induced pluripotent stem cell (hiPSC)-derived epithelial cultures support that Y333F heterozygotes also have altered structure and function of their tight junctions. Conclusion Our observations indicate an important role of C1orf106 in apical junctional complex (AJC) formation likely mediated by a regulation of the circumferential actin belt. This can affect other functions of AJC, like the establishment of cell polarity. AJC formation is important for epithelial repair after an injury and its dysregulation impairs the formation of an impermeable epithelial barrier, which likely facilitates the passage of microorganisms and the induction and maintenance of intestinal inflammation.

scholarly journals Evaluation of Sucrose Laurate as an Intestinal Permeation Enhancer for Macromolecules: Ex Vivo and In Vivo Studies

Pharmaceutics ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 565 ◽  
Author(s):  
Fiona McCartney ◽  
Mónica Rosa ◽  
David J. Brayden
Keyword(s):  
Plasma Membrane ◽  
Membrane Potential ◽  
Tight Junction ◽  
Oral Delivery ◽  
Ex Vivo ◽  
In Vivo Studies ◽  
Apparent Permeability ◽  
Sodium Caprate ◽  
Altered Expression ◽  
Junction Protein

Oral delivery of macromolecules requires permeation enhancers (PEs) adaptable to formulation. Sucrose laurate (SL) (D1216), a food grade surfactant, was assessed in Caco-2 monolayers, isolated rat intestinal tissue mucosae, and rat intestinal instillations. Accordingly, 1 mM SL increased the apparent permeability coefficient (Papp) of [14C]-mannitol and reduced transepithelial electrical resistance (TEER) across monolayers. It altered expression of the tight junction protein, ZO-1, increased plasma membrane potential, and decreased mitochondrial membrane potential in Caco-2 cells. The concentrations that increased flux were of the same order as those that induced cytotoxicity. In rat colonic tissue mucosae, the same patterns emerged in respect to the concentration-dependent increases in paracellular marker fluxes and TEER reductions with 5 mM being the key concentration. While the histology revealed some perturbation, ion transport capacity was retained. In rat jejunal and colonic instillations, 50 and 100 mM SL co-administered with insulin induced blood glucose reductions and achieved relative bioavailability values of 2.4% and 8.9%, respectively, on a par with the gold standard PE, sodium caprate (C10). The histology of the intestinal loops revealed little damage. In conclusion, SL is a candidate PE with high potential for emulsion-based systems. The primary action is plasma membrane perturbation, leading to tight junction openings and a predominant paracellular flux.

Campylobacter jejuni inhibits the absorptive transport functions of Caco-2 cells and disrupts cellular tight junctions

Microbiology ◽  
2005 ◽  
Vol 151 (7) ◽  
pp. 2451-2458 ◽  
Author(s):  
Amanda MacCallum ◽  
Simon P. Hardy ◽  
Paul H. Everest
Keyword(s):  
Tight Junction ◽  
Tight Junctions ◽  
Campylobacter Jejuni ◽  
Fluid Transport ◽  
Cell Function ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Ussing Chambers ◽  
Cell Monolayers ◽  
Junction Protein

Caco-2 cells are models of absorptive enterocytes. The net transport of fluid from apical to basolateral surfaces results in ‘domes' forming in differentiated monolayers. Here, the effect of Campylobacter jejuni on this process has been examined. C. jejuni caused no changes in short-circuit current upon infection of Caco-2 cell monolayers in Ussing chambers. Thus, no active secretory events could be demonstrated using this model. It was therefore hypothesized that C. jejuni could inhibit the absorptive function of enterocytes and that this may contribute to diarrhoeal disease. C. jejuni infection of fluid-transporting (‘doming’) Caco-2 cells resulted in a significant reduction in dome number, which correlated with a decrease in tight junction integrity in infected monolayers, when measured as transepithelial electrical resistance. Defined mutants of C. jejuni also reduced dome numbers in infected monolayers. C. jejuni also altered the distribution of the tight junction protein occludin within cell monolayers. The addition to monolayers of extracellular gentamicin prevented these changes, indicating the contribution of extracellular bacteria to this process. Thus, tight junction integrity is required for fluid transport in Caco-2 cell monolayers as leaky tight junctions cannot maintain support of transported fluid at the basolateral surface of infected cell monolayers. Inhibition of absorptive cell function, changes in epithelial resistance and rearrangement of tight junctional proteins such as occludin represent a potential diarrhoeal mechanism of C. jejuni.

Two classes of tight junctions are revealed by ZO-1 isoforms

1993 ◽  
Vol 264 (4) ◽  
pp. C918-C924 ◽  
Author(s):  
M. S. Balda ◽  
J. M. Anderson
Keyword(s):  
Tight Junction ◽  
Tight Junctions ◽  
Rna Splicing ◽  
Seminiferous Tubules ◽  
Junction Protein ◽  
Acid Domain ◽  
Ribonuclease Protection ◽  
Tissue Compartments ◽  
Junctional Resistance ◽  
Amino Acid Domain

The tight junction forms the intercellular barrier separating tissue compartments. The characteristics of this barrier are remarkably diverse among different epithelia and endothelia and are not explained by our limited knowledge of its molecular composition. Two isoforms of the 220-kDa tight junction protein ZO-1 result from alternative RNA splicing and differ by an internal 80-amino acid domain, termed alpha (E. Willott, M. S. Balda, M. Heintzman, B. Jameson, and J. M. Anderson. Am. J. Physiol. 262 (Cell Physiol. 31): C1119-C1124, 1992). Using antibodies specific for each isoform and double-labeled immunofluorescence microscopy, we observed that the ZO-1 alpha- isoform is restricted to junctions of endothelial cells and highly specialized epithelial cells of both seminiferous tubules (Sertoli cells) and renal glomeruli (podocytes); in contrast, the ZO-1 alpha+ isoform is expressed in cells of all other epithelia examined. Both immunoblotting and ribonuclease protection analysis confirmed this pattern of expression. This distribution does not correlate with differences in junctional resistance or ultrastructural complexity. Instead, we observe a correlation with junctional plasticity; ZO-1 alpha- is expressed in structurally dynamic junctions, whereas ZO-1 alpha+ is expressed in those which are less dynamic. This is the first molecular distinction among tight junctions and reveals a fundamental dichotomy with implications for how the paracellular barriers of endothelia and epithelia are regulated.

Localization and differential expression of two isoforms of the tight junction protein ZO-1

1992 ◽  
Vol 262 (5) ◽  
pp. C1119-C1124 ◽  
Author(s):  
E. Willott ◽  
M. S. Balda ◽  
M. Heintzelman ◽  
B. Jameson ◽  
J. M. Anderson
Keyword(s):  
Tight Junction ◽  
Tight Junctions ◽  
Cell Lines ◽  
Dna Amplification ◽  
Immunoblot Analysis ◽  
Protein Isoforms ◽  
Variable Expression ◽  
Junction Protein ◽  
Epithelial Cell Lines ◽  
Normal Rat

ZO-1 is a peripheral membrane protein of approximately 225 kDa located on the cytoplasmic side of all tight junctions. ZO-1 cDNA sequencing disclosed the presence of a 240-bp sequence in only some of the ZO-1 cDNAs studied. This 240-bp region encoded an inframe insertion of 80 amino acids, named motif-alpha. Expression of the predicted transcripts in normal rat and human tissues and in human epithelial cell lines (Caco-2, T84, Hep G2) was shown by reverse transcription of RNA and then DNA amplification. Immunoblot analysis showed both protein isoforms were present; however, in different cell lines, their amounts differed markedly relative to each other. Immunolocalization at light and ultrastructural levels, using antibodies generated against motif-alpha or shared sequences flanking it, indicated both forms localized indistinguishably to tight junctions. These observations demonstrate the existence and variable expression of ZO-1 isoforms and raise the question whether these isoforms contribute to tight junction diversity in different epithelia.

116. Contribution of claudin-11 to the inter-Sertoli cell tight junction, in vitro

2005 ◽  
Vol 17 (9) ◽  
pp. 72
Author(s):  
M. J. McCabe ◽  
P. G. Stanton
Keyword(s):  
Tight Junction ◽  
Mrna Expression ◽  
Sertoli Cell ◽  
Adhesion Molecule ◽  
Sertoli Cells ◽  
Adherens Junction ◽  
Adherens Junction Protein ◽  
Junction Protein

The inter-Sertoli cell tight junction (TJ) forms the blood testis barrier (BTB) between Sertoli cells and is composed of three major transmembrane proteins: claudin-11, occludin and junctional adhesion molecule. Formation of the BTB occurs during puberty associating with an increase in circulating gonadotrophins. Claudin-11 and occludin are hormonally regulated in vitro although their importance to the function of the TJ is unknown. The aim of this study was to investigate the contribution of claudin-11 to the inter-Sertoli cell TJ in vitro by blocking gene expression using RNA interference. Two claudin-11-specific siRNA fragments were designed for this purpose. Sertoli cells in primary culture formed stable TJs within 5 days as measured by transepithelial electrical resistance (TER). The addition of siRNA for 2 days resulted in a significant (P < 0.01) 55% (mean, SD, n = 4 cultures) decrease in TER along with a major reduction in claudin-11 localisation to the TJ as assessed by immunocytochemistry. The specificity of the siRNA was shown by the presence of extensive immunostaining of occludin and of the adherens junction protein β-catenin in the same treatments. Similarly, claudin-11 mRNA expression significantly (P < 0.01) decreased by 71% (mean, SD, n = 3 cultures) in response to both claudin-11 siRNA fragments. Occludin mRNA expression was not affected. It is concluded that claudin-11 contributes at least 55% to the function of the rat Sertoli cell TJ in vitro. It is hypothesised that the remaining 45% of TJ function can be attributed to other integral proteins, such as occludin and junctional adhesion molecule. It is expected that claudin-11 and other TJ proteins play a pivotal role in the function of the BTB in vivo with potential implications in fertility and contraception.

Altered expression of tight junction molecules in alveolar septa in lung injury and fibrosis

2012 ◽  
Vol 302 (2) ◽  
pp. L193-L205 ◽  
Author(s):  
Hiromitsu Ohta ◽  
Shigeki Chiba ◽  
Masahito Ebina ◽  
Mikio Furuse ◽  
Toshihiro Nukiwa
Keyword(s):  
Epithelial Cells ◽  
Pulmonary Fibrosis ◽  
Lung Injury ◽  
Tight Junction ◽  
Tight Junctions ◽  
Molecular Mechanisms ◽  
Transforming Growth Factor ◽  
Alveolar Epithelial Cells ◽  
Altered Expression ◽  
Alveolar Epithelial

The dysfunction of alveolar barriers is a critical factor in the development of lung injury and subsequent fibrosis, but the underlying molecular mechanisms remain poorly understood. To clarify the pathogenic roles of tight junctions in lung injury and fibrosis, we examined the altered expression of claudins, the major components of tight junctions, in the lungs of disease models with pulmonary fibrosis. Among the 24 known claudins, claudin-1, claudin-3, claudin-4, claudin-7, and claudin-10 were identified as components of airway tight junctions. Claudin-5 and claudin-18 were identified as components of alveolar tight junctions and were expressed in endothelial and alveolar epithelial cells, respectively. In experimental bleomycin-induced lung injury, the levels of mRNA encoding tight junction proteins were reduced, particularly those of claudin-18. The integrity of the epithelial tight junctions was disturbed in the fibrotic lesions 14 days after the intraperitoneal instillation of bleomycin. These results suggest that bleomycin mainly injured alveolar epithelial cells and impaired alveolar barrier function. In addition, we analyzed the influence of transforming growth factor-β (TGF-β), a critical mediator of pulmonary fibrosis that is upregulated after bleomycin-induced lung injury, on tight junctions in vitro. The addition of TGF-β decreased the expression of claudin-5 in human umbilical vein endothelial cells and disrupted the tight junctions of epithelial cells (A549). These results suggest that bleomycin-induced lung injury causes pathogenic alterations in tight junctions and that such alterations seem to be induced by TGF-β.

scholarly journals Crosstalk between Androgen-ZIP9 Signaling and Notch Pathway in Rodent Sertoli Cells

2020 ◽  
Vol 21 (21) ◽  
pp. 8275
Author(s):  
Alicja Kamińska ◽  
Sylwia Marek ◽  
Laura Pardyak ◽  
Małgorzata Brzoskwinia ◽  
Barbara Bilinska ◽  
...  
Keyword(s):  
Androgen Receptor ◽  
Sertoli Cell ◽  
Sertoli Cells ◽  
Cell Function ◽  
Active Form ◽  
Notch Pathway ◽  
Altered Expression ◽  
Effector Genes ◽  
Pathway Activation ◽  
Hes1 Expression

Our recent study demonstrated altered expression of Notch ligands, receptors, and effector genes in testes of pubertal rats following reduced androgen production or signaling. Herein we aimed to explore the role of nuclear androgen receptor (AR) and membrane androgen receptor (Zrt- and Irt-like protein 9; ZIP9) in the regulation of Notch pathway activation in rodent Sertoli cells. Experiments were performed using TM4 and 15P-1 Sertoli cell lines and rat primary Sertoli cells (PSC). We found that testosterone (10−8 M–10−6 M) increased the expression of Notch1 receptor, its active form Notch1 intracellular domain (N1ICD) (p < 0.05, p < 0.01, p < 0.001), and the effector genes Hey1 (p < 0.05, p < 0.01, p < 0.001) and Hes1 (p < 0.05, p < 0.001) in Sertoli cells. Knockdown of AR or ZIP9 as well as antiandrogen exposure experiments revealed that (i) action of androgens via both AR and ZIP9 controls Notch1/N1ICD expression and transcriptional activity of recombination signal binding protein (RBP-J), (ii) AR-dependent signaling regulates Hey1 expression, (iii) ZIP9-dependent pathway regulates Hes1 expression. Our findings indicate a crosstalk between androgen and Notch signaling in Sertoli cells and point to cooperation of classical and non-classical androgen signaling pathways in controlling Sertoli cell function.

scholarly journals Potential Regulatory Effects of Corticotropin-Releasing Factor on Tight Junction-Related Intestinal Epithelial Permeability are Partially Mediated by CK8 Upregulation

2017 ◽  
Vol 44 (3) ◽  
pp. 1161-1173 ◽  
Author(s):  
Hu Yue ◽  
Lu  Bin ◽  
Chen Chaoying ◽  
Zhang Meng ◽  
Li Meng ◽  
...  
Keyword(s):  
Tight Junction ◽  
Tight Junctions ◽  
Intestinal Permeability ◽  
Corticotropin Releasing Factor ◽  
Intestinal Epithelial ◽  
Epithelial Permeability ◽  
Expression Levels ◽  
Rhoa Activity ◽  
Junction Protein ◽  
Regulatory Effects

Background/Aims: Intestinal permeability and stress have been implicated in the pathophysiology of irritable bowel syndrome (IBS). Cytokeratin 8 (CK8), for the first time, has been shown to mediate corticotropin-releasing factor (CRF)-induced changes in intestinal permeability in animal models of IBS. In this study, we investigated the regulatory effects of CRF on the permeability of human intestinal epithelial cells through the CK8-mediated tight junction. Methods: The expression levels of corticotropin-releasing factor receptor 1 (CRFR1) and corticotropin-releasing factor receptor 2 (CRFR2) on the HT29 cell surface were determined by immunofluorescence, RT-PCR, and Western blotting. After treatment with 100 nM CRF for 72 h, the translocation of FITC-labelled dextran was measured in a transwell chamber; the structural changes of tight junctions were observed under transmission electron microscopy; the expression levels of CK8, F-actin and tight junction proteins ZO-1, claudin-1, and occludin were detected by immunoblotting and immunofluorescence. The activity of RhoA was detected by immunoprecipitation. Furthermore, the effects of CRF on intestinal epithelial permeability were examined in CK8-silenced HT29 cells, which were constructed by shRNA interference. Results: CRF treatment increased FITC-labelled dextran permeability, caused the opening of tight junctions, induced increased fluorescence intensity of CK8 and decreased the intensities of ZO-1, claudin-1, and occludin, together with structural disruption. The expression levels of F-actin, occludin, claudin-1, and ZO-1 were downregulated. RhoA activity peaked at 30 min after CRF treatment. CRF-induced increased permeability, and downregulation of claudin-1 and occludin were not blocked by CK8 silencing. Nevertheless, CK8 silencing blocked the effects of CRF regarding the decrease in the expression levels of F-action and ZO-1 and increase in RhoA activity. Conclusion: CRF may increase intestinal epithelial permeability by upregulating CK8 expression, activating the RhoA signalling pathway, promoting intestinal epithelial actin remodelling, and decreasing the expression of the tight junction protein ZO-1. Other CK8-independent pathways may be involved in the downregulation of claudin-1 and occludin, which might also contribute to increased intestinal epithelial permeability.

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