OBJECTIVE: To investigate the protective effects of total saponins from Panax japonicus (TSPJ) against high-fat dietinduced testicular Sertoli cell junction damage in mice. METHODS: Forty male C57BL/6J mice were randomized into normal diet group, high-fat diet group, and low-dose (25 mg/kg) and high-dose (75 mg/kg) TSPJ treatment groups (n=10). The mice in the normal diet group were fed a normal diet, while the mice in the other groups were fed a high-fat diet. After TSPJ treatment via intragastric administration for 5 months, the testes and epididymis of the mice were collected for measurement of weight, testicular and epididymal indices and sperm parameters. HE staining was used for histological evaluation of the testicular tissues and measurement of seminiferous tubule diameter and seminiferous epithelium height. The expression levels of ZO-1, occludin, claudin11, N-cadherin, E-cadherin and β-catenin in Sertoli cells were detected with Western blot, and the localization and expression levels of ZO-1 and β-catenin in the testicular tissues were detected with immunofluorescence assay. The protein expressions of LC3B, p-AKT and p-mTOR in testicular Sertoli cells were detected using double immunofluorescence assay. RESULTS: Treatment with TSPJ significantly improved high-fat diet-induced testicular dysfunction by reducing body weight (P < 0.001), increasing testicular and epididymal indices (P < 0.05), and improving sperm concentration and sperm viability (P < 0.05). TSPJ ameliorated testicular pathologies and increased seminiferous epithelium height of the mice with high-fat diet feeding (P < 0.05) without affecting the seminiferous tubule diameter. TSPJ significantly increased the expression levels of ZO-1, occludin, N-cadherin, E-cadherin and β-catenin (P < 0.05) but did not affect claudin11 expression in the testicular tissues. Immunofluorescence assay showed that TSPJ significantly increased ZO-1 and β-catenin expression in the testicular tissues (P < 0.001), downregulated LC3B expression and upregulated p-AKT and p-mTOR expressions in testicular Sertoli cells. CONCLUSION TSPJ alleviates high-fat diet-induced damages of testicular Sertoli cell junctions and spermatogenesis possibly by activating the AKT/mTOR signaling pathway and inhibiting autophagy of testicular Sertoli cells.
Male ; Animals ; Mice ; Mice, Inbred C57BL ; Testis ; Sertoli Cells ; beta Catenin ; Diet, High-Fat ; Occludin ; Proto-Oncogene Proteins c-akt ; Seeds ; Cadherins ; Intercellular Junctions

PURPOSE: Despite the well-known anti-inflammatory effects of vitamin D in periodontal health, its mechanism has not been fully elucidated. In the present study, the effect of vitamin D on strengthening E-cadherin junctions (ECJs) was explored in human gingival keratinocytes (HGKs). ECJs are the major type of intercellular junction within the junctional epithelium, where loose intercellular junctions develop and microbial invasion primarily occurs. METHODS: HOK-16B cells, an immortalized normal human gingival cell line, were used for the study. To mimic the inflammatory environment, cells were treated with tumor necrosis factor-alpha (TNF-α). Matrix metalloproteinases (MMPs) in the culture medium were assessed by an MMP antibody microarray and gelatin zymography. The expression of various molecules was investigated using western blotting. The extent of ECJ development was evaluated by comparing the average relative extent of the ECJs around the periphery of each cell after immunocytochemical E-cadherin staining. Vitamin D receptor (VDR) expression was examined via immunohistochemical analysis. RESULTS: TNF-α downregulated the development of the ECJs of the HGKs. Dissociation of the ECJs by TNF-α was accompanied by the upregulation of MMP-9 production and suppressed by a specific MMP-9 inhibitor, Bay 11-7082. Exogenous MMP-9 decreased the development of ECJs. Vitamin D reduced the production of MMP-9 and attenuated the breakdown of ECJs in the HGKs treated with TNF-α. In addition, vitamin D downregulated TNF-α-induced nuclear factor kappa B (NF-κB) signaling in the HGKs. VDR was expressed in the gingival epithelium, including the junctional epithelium. CONCLUSIONS: These results suggest that vitamin D may avert TNF-α-induced downregulation of the development of ECJs in HGKs by decreasing the production of MMP-9, which was upregulated by TNF-α. Vitamin D may reinforce ECJs by downregulating NF-κB signaling, which is upregulated by TNF-α. Strengthening the epithelial barrier may be a way for vitamin D to protect the periodontium from bacterial invasion.
Bays ; Blotting, Western ; Cadherins ; Cell Line ; Down-Regulation ; Epithelial Attachment ; Epithelium ; Gelatin ; Humans ; Intercellular Junctions ; Keratinocytes ; Matrix Metalloproteinase 9 ; Matrix Metalloproteinases ; NF-kappa B ; Periodontium ; Receptors, Calcitriol ; Tumor Necrosis Factor-alpha ; Up-Regulation ; Vitamin D ; Vitamins

Maintenance of cell junctions plays a crucial role in the regulation of cellular functions including cell proliferation, permeability, and cell death. Disruption of cell junctions is implicated in a variety of human disorders, such as inflammatory diseases and cancers. Understanding molecular regulation of cell junctions is important for development of therapeutic strategies for intervention of human diseases. Ubiquitination is an important type of post-translational modification that primarily regulates endogenous protein stability, receptor internalization, enzyme activity, and protein-protein interactions. Ubiquitination is tightly regulated by ubiquitin E3 ligases and can be reversed by deubiquitinating enzymes. Recent studies have been focusing on investigating the effect of protein stability in the regulation of cell-cell junctions. Ubiquitination and degradation of cadherins, claudins, and their interacting proteins are implicated in epithelial and endothelial barrier disruption. Recent studies have revealed that ubiquitination is involved in regulation of Rho GTPases' biological activities. Taken together these studies, ubiquitination plays a critical role in modulating cell junctions and motility. In this review, we will discuss the effects of ubiquitination and deubiquitination on protein stability and expression of key proteins in the cell-cell junctions, including junction proteins, their interacting proteins, and small Rho GTPases. We provide an overview of protein stability in modulation of epithelial and endothelial barrier integrity and introduce potential future search directions to better understand the effects of ubiquitination on human disorders caused by dysfunction of cell junctions.
Animals ; Humans ; Inflammation ; metabolism ; pathology ; Intercellular Junctions ; metabolism ; Neoplasms ; metabolism ; pathology ; Protein Stability ; Ubiquitin-Protein Ligases ; metabolism ; Ubiquitination

Epidermal barrier formation and the maintenance of barrier homeostasis are essential to protect us from the external environments and organisms. Moreover, impaired keratinocytes differentiation and dysfunctional skin barrier can be the primary causes or aggravating factors for many inflammatory skin diseases including atopic dermatitis and psoriasis. Therefore, understanding the regulation mechanisms of keratinocytes differentiation and skin barrier homeostasis is important to understand many skin diseases and establish an effective treatment strategy. Calcium ions (Ca²⁺) and their concentration gradient in the epidermis are essential in regulating many skin functions, including keratinocyte differentiation, skin barrier formation, and permeability barrier homeostasis. Recent studies have suggested that the intracellular Ca²⁺ stores such as the endoplasmic reticulum (ER) are the major components that form the epidermal calcium gradient and the ER calcium homeostasis is crucial for regulating keratinocytes differentiation, intercellular junction formation, antimicrobial barrier, and permeability barrier homeostasis. Thus, both Ca²⁺ release from intracellular stores, such as the ER and Ca²⁺ influx mechanisms are important in skin barrier. In addition, growing evidences identified the functional existence and the role of many types of calcium channels which mediate calcium flux in keratinocytes. In this review, the origin of epidermal calcium gradient and their role in the formation and regulation of skin barrier are focused. We also focus on the role of ER calcium homeostasis in skin barrier. Furthermore, the distribution and role of epidermal calcium channels, including transient receptor potential channels, store-operated calcium entry channel Orai1, and voltage-gated calcium channels in skin barrier are discussed.
Calcium Channels ; Calcium* ; Dermatitis, Atopic ; Endoplasmic Reticulum ; Epidermis ; Homeostasis ; Intercellular Junctions ; Ions ; Keratinocytes ; Permeability ; Psoriasis ; Skin Diseases ; Skin* ; Transient Receptor Potential Channels

Men with diabetic erectile dysfunction (ED) respond poorly to the currently available oral phosphodiesterase-5 inhibitors. Therefore, functional therapies for diabetic ED are needed. Stromal vascular fraction (SVF) and the adenovirus-mediated cartilage oligomeric matrix angiopoietin-1 (Ad-COMP-Ang1) gene are known to play critical roles in penile erection. We previously reported that SVF and Ad-COMP-Ang1 have only a short-term effect in restoring erectile function. Further improvements to ED therapy are needed for long-lasting effects. In the present study, we aimed to test if the combination of SVF and Ad-COMP-Ang1 could extend the erection effect in diabetic ED. We found that the combination therapy showed a long-term effect in restoring erectile function through enhanced penile endothelial and neural cell regeneration. Combination therapy with SVF and Ad-COMP-Ang1 notably restored cavernous endothelial cell numbers, pericyte numbers, endothelial cell-cell junctions, decreased cavernous endothelial cell permeability, and promoted neural regeneration for at least 4 weeks in diabetic mice. In summary, this is an initial description of the long-term effect of combination therapy with SVF and Ad-COMP-Ang1 in restoring erectile function through a dual effect on endothelial and neural cell regeneration. Such combination therapy may have therapeutic potential for the treatment of diabetic ED.
Angiopoietin-1/genetics* ; Animals ; Diabetes Mellitus, Experimental/metabolism* ; Endothelium, Vascular/metabolism* ; Erectile Dysfunction/therapy* ; Genetic Therapy/methods* ; Intercellular Junctions/metabolism* ; Male ; Mesenchymal Stem Cell Transplantation ; Mice ; Penile Erection/physiology* ; Permeability

PURPOSE: The entry of bacteria or harmful substances through the epithelial seal of human gingival keratinocytes (HGKs) in the junctional epithelium (JE) is blocked by specialized intercellular junctions such as E-cadherin junctions (ECJs). However, the influence of roughened substrates, which may occur due to apical migration of the JE, root planing, or peri-implantitis, on the development of the ECJs of HGKs remains largely unknown. METHODS: HGKs were cultured on substrates with varying levels of roughness, which were prepared by rubbing hydrophobic polystyrene dishes with silicon carbide papers. The activity of c-Jun N-terminal kinase (JNK) was inhibited with SP600125 or by transfection with JNK short hairpin RNA. The development of intercellular junctions was analyzed using scanning electron microscopy or confocal laser scanning microscopy after immunohistochemical staining of the cells for E-cadherin. The expression level of phospho-JNK was assessed by immunoblotting. RESULTS: HGKs developed tight intercellular junctions devoid of wide intercellular gaps on smooth substrates and on rough substrates with low-nanometer dimensions (average roughness [Ra]=121.3±13.4 nm), although the ECJs of HGKs on rough substrates with low-nanometer dimensions developed later than those of HGKs on smooth substrates. In contrast, HGKs developed short intercellular junctions with wide intercellular gaps on rough substrates with mid- or high-nanometer dimensions (Ra=505.3±115.3 nm, 867.0±168.6 nm). Notably, the stability of the ECJs was low on the rough substrates, as demonstrated by the rapid destruction of the cell junction following calcium depletion. Inhibition of JNK activity promoted ECJ development in HGKs. JNK was closely associated with cortical actin in the regulation of ECJs in HGKs. CONCLUSIONS: These results indicate that on rough substrates with nanometer dimensions, the ECJs of HGKs develop slowly or defectively, and that this effect can be reversed by inhibiting JNK.
Actins ; Bacteria ; Cadherins* ; Calcium ; Dental Implants ; Epithelial Attachment ; Humans* ; Immunoblotting ; Intercellular Junctions ; JNK Mitogen-Activated Protein Kinases ; Keratinocytes* ; Microscopy, Confocal ; Microscopy, Electron, Scanning ; Peri-Implantitis ; Periodontal Diseases ; Polystyrenes ; Re-Epithelialization ; RNA, Small Interfering ; Root Planing ; Silicon ; Transfection

The gut epithelial barrier, which is composed of the mucosal layer and the intestinal epithelium, has multiple defense mechanisms and interconnected regulatory mechanisms against enteric microbial pathogens. However, many bacterial pathogens have highly evolved infectious stratagems that manipulate mucin production, epithelial cell-cell junctions, cell death, and cell turnover to promote their replication and pathogenicity in the gut epithelial barrier. In this review, we focus on current knowledge about how bacterial pathogens regulate mucin levels to circumvent the epithelial mucus barrier and target cell-cell junctions to invade deeper tissues and increase their colonization. We also describe how bacterial pathogens manipulate various modes of epithelial cell death to facilitate bacterial dissemination and virulence effects. Finally, we discuss recent investigating how bacterial pathogens regulate epithelial cell turnover and intestinal stem cell populations to modulate intestinal epithelium homeostasis.
Colon ; Defense Mechanisms ; Epithelial Cells ; Homeostasis ; Intercellular Junctions ; Intestinal Mucosa ; Mucins ; Mucus ; Stem Cells ; Tight Junctions ; Virulence

OBJECTIVETo study on the expression patterns of proteins associated with cell junctions in the developing mouse testes.

METHODThe expression levels of reproductive related cell lines spermatogonia cell line GC1 spg, spermatocyte cell line GC2 spg, leydig cell line TM3, and sertoli cell line TM4, primary sertoli cells, and 1-6-week mouse testes were analyzed using Western blot.

RESULTSThe sertoli cell junction-associated membrane proteins adhesion molecule A, Occludin and Claudin, and the sertoli-germ cell junction-associated membrane proteins junctional adhesion molecule C, Nectin-3, and E-cadherin were stage-specific in the seminiferous tubules in the mouse testes. The adaptor proteins associated with cell juctions zonula occludens-1, zonula occludens-2, Afadin, Β-catenin, and CD2-associated protein were not stage-specific in the seminiferous tubules in the mouse testes.

CONCLUSIONSIn the seminiferous tubules in the mouse testes, the membrane proteins associated with cell junctions are stage-specific. However, the expressions of adaptor proteins associated with cell junctions do not obviously change.

Adaptor Proteins, Signal Transducing ; metabolism ; Animals ; Cdh1 Proteins ; metabolism ; Cell Adhesion Molecules ; metabolism ; Cell Line ; Cytoskeletal Proteins ; metabolism ; Humans ; Intercellular Junctions ; metabolism ; Male ; Membrane Proteins ; metabolism ; Mice ; Microfilament Proteins ; metabolism ; Nectins ; Seminiferous Tubules ; cytology ; metabolism ; Sertoli Cells ; cytology ; Testis ; cytology ; Zonula Occludens-1 Protein ; metabolism ; Zonula Occludens-2 Protein ; metabolism ; beta Catenin ; metabolism

Tight junctions (TJs) form continuous intercellular contacts in intercellular junctions. TJs involve integral proteins such as occludin (OCLN) and claudins (CLDNs) as well as peripheral proteins such as zona occludens-1 (ZO-1) and junctional adhesion molecules (JAMs). TJs control paracellular transportation across cell-to-cell junctions. Although TJs have been studied for several decades, comparison of the transcriptional-translational levels of these molecules in canine organs has not yet been performed. In this study, we examined uterine expression of CLDNs, OCLN, junction adhesion molecule-A, and ZO-1 in canine. Expression levels of canine uterine TJ proteins, including CLDN1, 2, 4, 5, JAM-A, ZO-1, and OCLN, were measured using reverse transcription PCR, real-time PCR, and Western blotting, whereas TJs distribution was determined by immunohistochemistry. The mRNA and protein expression levels of OCLN, CLDN-1, 4, JAM-1, and ZO-1 were identified in the uterus. Immunohistochemistry demonstrated that TJs were localized to the endometrium and/or myometrium of the uterus. Our results show that canine TJ proteins, including CLDNs, OCLN, JAM-A, and ZO-1, were expressed in the canine uterus. Taken together, these proteins may perform unique physiological roles in the uterus. Therefore, these findings may serve as a basis for further studies on TJ proteins and their roles in the physiological or pathological condition of the canine uterus.
Animals ; Blotting, Western ; Claudins ; Dogs ; Endometrium ; Female ; Herpes Zoster ; Immunohistochemistry ; Intercellular Junctions ; Junctional Adhesion Molecules ; Mice ; Myometrium ; Occludin ; Physiology ; Polymerase Chain Reaction ; Real-Time Polymerase Chain Reaction ; Reverse Transcription ; RNA, Messenger ; Tight Junctions* ; Transportation ; Uterus*

OBJECTIVETo explore the molecular mechanism of dutasteride inhibiting fertility by studying its effects on the expressions of the epididymal epithelial junction proteins Claudin1 and β-catenin in rats.

METHODSSixteen 3-month-old SD male rats were equally divided into an experimental and a negative control group to be treated intragastrically with dutasteride at 40 mg/kg per day and the same dose of solvent, respectively, for 14 consecutive days. Then, the sperm motility and morphology of the rats were detected by computer-assisted sperm analysis, the serum levels of testosterone (T) and dihydrotestosterone (DHT) measured by ELISA, changes in the tight junction of epididymal cells observed under the transmission electron microscope, the protein and gene expressions of Claudin1 and β-catenin determined by RT-PCR and immunohistochemistry, and the conception rate of the mated female rats calculated.

RESULTSDutasteride significantly suppressed the serum DHT level, sperm motility, and fertility of the rats (P <0.05). Interspaces between epididymal epithelial cell tight junctions were observed, the volume of epididymal fluid obviously increased, and the expressions of Claudin1 and β-catenin gene and protein remarkably downregulated in the experimental rats (P <0.05).

CONCLUSIONDutasteride can significantly inhibit the fertility of male rats by reducing the serum DHT level, suppressing Claudin1 and β-catenin expressions, and damaging epididymal epithelial cell junctions.

Animals ; Azasteroids ; pharmacology ; Claudin-1 ; metabolism ; Dihydrotestosterone ; blood ; Dutasteride ; Epididymis ; drug effects ; metabolism ; Female ; Fertility ; drug effects ; Humans ; Intercellular Junctions ; drug effects ; Male ; Rats ; Rats, Sprague-Dawley ; Sperm Motility ; drug effects ; Testosterone ; blood ; Urological Agents ; pharmacology ; beta Catenin ; metabolism