Claudins, which are known as transmembrane proteins play an essential role in tight junctions (TJs) to form physical barriers and regulate paracellular transportation. To understand equine diseases, it is helpful to measure the tissue-specific expression of TJs in horses. Major equine diseases such as colic and West Nile cause damage to TJs. In this study, the expression level and distribution of claudin-1, -2, -4, and -5 in eight tissues were assessed by Western blotting and immunohistochemistry methods. Claudin-1 was primarily identified in the lung, duodenum, and uterus, claudin-2 was evenly observed in equine tissues, claudin-4 was abundantly detected in the liver, kidney and uterus, and claudin-5 was strongly expressed in the lung, duodenum, ovary, and uterus, as determined by Western blotting method. The localization of equine claudins was observed by immunohistochemistry methods. These findings provide knowledge regarding the expression patterns and localization of equine claudins, as well as valuable information to understand tight junction-related diseases according to tissue specificity and function of claudins in horses.
Animals ; Architectural Accessibility ; Blotting, Western ; Claudin-1* ; Claudin-2 ; Claudin-4 ; Claudin-5 ; Claudins ; Colic ; Duodenum ; Female ; Horse Diseases ; Horses ; Immunohistochemistry ; Kidney ; Liver ; Lung ; Methods ; Organ Specificity ; Ovary ; Tight Junctions ; Transportation ; Uterus

OBJECTIVE: Cell to cell and cell to extracellular matrix interaction are crucial in tumor development and progression. Tight junction proteins such as claudins and zonula occludens-1 (ZO-1) play an important role in these processes. This study was performed to investigate the difference of expressions of claudin-1, claudin-4 and ZO-1 in low grade squamous intraepithelial lesion (LSIL), high grade squamous intraepithelial lesion (HSIL), and invasive squamous cell carcinoma (ISCC) of the uterine cervix. METHODS: The expressions of claudin-1, claudin-4 and ZO-1 were evaluated using immunohistochemical staining in 78 cervical tissue specimens (LSIL 22 case, HSIL 36 case, and ISCC 20 case). RESULTS: Claudin-1 expression was positive in 40.9% of LSIL, in 94.0% of HSIL and in 20.0% of ISCC. The expression of claudin-1 was significantly high in HSIL (p=0.0001). Claudin-4 expression was positive in 31.8% of LSIL, in 41.7% of HSIL and in 25.0% of ISCC. The expression of claudin-4 was high in HSIL, but it was not statistically different. ZO-1 expression was positive in 13.6% of LSIL, in 41.7% of HSIL, and in 25.5% of ISCC. The expression of ZO-1 was significantly high in HSIL (p=0.011). CONCLUSION: These results indicate increased expressions of claudin-1 and ZO-1 in the HSIL that includes cervical intraepithelial neoplasia (CIN) 2 and 3, which decrease during progression to cervical cancer.
Carcinoma, Squamous Cell* ; Cervical Intraepithelial Neoplasia* ; Cervix Uteri ; Claudin-1* ; Claudin-4* ; Claudins ; Extracellular Matrix ; Female ; Tight Junction Proteins ; Uterine Cervical Neoplasms

BACKGROUND: The claudins are a family of transmembrane proteins associated with tight junctions and they are critical for maintaining cell-to-cell adhesion in sheets of epithelial cells. However, their role in the progression of cancer remains largely unexplored. The aims of this study were to evaluate the expression patterns of claudin-1 and -4 in benign lesions and invasive ductal carcinomas (IDC) of the breast, and relationships between the expression of these markers and the clinicopathological characteristics in IDC patients. METHODS: We examined the claudin-1 and -4 protein expressions by performing immunohistochemical stainings in 54 benign lesions and 120 IDCs via the tissue microarray method. We evaluated the correlation between the expression of these markers and the clinicopathological characteristics of IDC. RESULTS: The expressions of claudin-1 (p=0.099) and -4 (p=0.000) were up-regulated in IDCs as compared with benign lesions. The claudin-1 expression correlated with the loss of estrogen receptor (p=0.036) and progesterone receptor (p=0.011). The claudin-4 expression correlated with lymph node metastasis (p=0.043), the nuclear grade (p=0.030), the histologic grade (p=0.007), and the loss of estrogen receptor (p=0.001) and progesterone receptor (p= 0.029). CONCLUSIONS: These results suggest that claudin-1 and -4 may play a significant role in the carcinogenesis of IDC of the breast and these may represent novel markers for this disease.
Breast* ; Carcinogenesis ; Carcinoma, Ductal* ; Claudin-1* ; Claudin-4 ; Claudins ; Epithelial Cells ; Estrogens ; Humans ; Immunohistochemistry ; Lymph Nodes ; Neoplasm Metastasis ; Receptors, Progesterone ; Tight Junctions

PURPOSE: The purpose of this study was to evaluate the correlation between the expression of claudins and prognostic factors in patients with prostate cancer. MATERIALS AND METHODS: The subjects of this study were 48 patients who had undergone surgery for prostate cancer. The Gleason score (6 or lower, 7 or higher), prostate-specific antigen (PSA) level, T stage, biochemical recurrence, local recurrence, and distant metastasis were compared according to the expression of claudin-1 and claudin-5 in prostate cancer. RESULTS: In the group with a low expression of claudin-1, the Gleason score was 7 points or higher in 18 cases (82%) and 6 points or lower in 4 cases (18%). In the group with a high expression of claudin-1, the Gleason score was 7 points or higher in 13 cases (50%) and 6 points or lower in 13 cases (50%). Thus, the low-expression group had more cases with a Gleason score of 7 or higher (p=0.022). The group with a low expression of claudin-5 also had more cases with a Gleason score of 7 or higher (p=0.011). The mean PSA values in the groups with a low and high expression of claudin-1 were 9.6 ng/ml and 5.6 ng/ml, respectively (p=0.007). A low expression of claudin-5 was also associated with a high PSA value (p=0.002). There was no statistical difference in the expression of claudin-1 and claudin-5 by T stage, biochemical recurrence, local recurrence, or distant metastasis. CONCLUSIONS: The low expression of claudin-1, claudin-5 was associated with a Gleason score of 7 or higher and a high PSA value in prostate cancer.
Claudin-1 ; Claudin-5 ; Claudins ; Humans ; Neoplasm Grading ; Neoplasm Metastasis ; Prostate ; Prostate-Specific Antigen ; Prostatic Neoplasms ; Recurrence

OBJECTIVEThe aim of this study was to explore the possibility of creating a toxin, C-CPE-ETA', by fusing C-terminal high affinity binding domain of CPE (C-CPE) with a truncated form of Pseudomonas aeruginosa exotoxin A (ETA') and to examine whether C-CPE-ETA' could specifically target CLDN-3, 4 molecule and the targeted toxin was cytotoxic against CLDN-3,4-overexpressing ovarian cancer.

METHODSCLDN-3 and CLDN-4 expressions were analyzed at the mRNA level in three ovarian cancer cell lines and epithelial ovarian cancer tissues from 20 patients. After transforming an expression plasmid of C-CPE-ETA' into E. coli BL21 (DE3) plysS strain, the recombinant protein was purified using His-Bind resin chromatography column and analyzed by Western blot and Coomassie blue staining. The specific binding, proapoptotic and cytolytic activities were evaluated by flow cytometry, fluorescence microscopy with the JC-1 probe and MTT assay in CLDN-3,4-overexpressing ovarian cancer cells.

RESULTSQuantitive RT-PCR results showed there existed high levels of CLDN-3 and CLDN-4 in ovarian cancer cells, CAOV3, OVCAR3 and SKOV3. Moreover, high expressions of CLDN-3 and CLDN-4 were observed in 90.0% (18/20) and 60.0% (12/20) of ovarian cancer tissues, with an expression level 10-fold higher than that in the normal ovarian tissue. A 58 000 recombinant protein C-CPE-ETA' was demonstrated by Western blot and Coomassie blue staining. Purified and recombinant C-CPE-ETA' was bound with high affinity to CLDN-3,4-overexpressing ovarian cancer cells, CAOV3, OVCAR3 and SKOV3 cells. C-CPE-ETA' was strongly proapoptotic and cytotoxic towards the CLDN-3,4-overexpressing ovarian cancer cells. The concentration of IC(50) was 7.364 ng/ml for CAOV3 cells, 8.110 ng/ml for OVCAR3 cells and 22.340 ng/ml for SKOV3 cells, respectively. However, control CLDN-3,4-deficient cell line HUVEC was not susceptible to the recombinant C-CPE-ETA' at a concentration up to 10 µg/ml.

CONCLUSIONSThe C-CPE-ETA' protein exhibits remarkably specific cytotoxicity for CLDN-3,4-overexpressing ovarian cancer cells. Its therapeutic potential warrants further development for ovarian cancer molecular targeted therapy.

ADP Ribose Transferases ; metabolism ; physiology ; Apoptosis ; Bacterial Toxins ; metabolism ; Cell Line, Tumor ; Claudin-3 ; Claudin-4 ; Claudins ; genetics ; metabolism ; Enterotoxins ; metabolism ; physiology ; Exotoxins ; metabolism ; physiology ; Female ; Humans ; Immunotoxins ; metabolism ; Ovarian Neoplasms ; metabolism ; pathology ; RNA, Messenger ; metabolism ; Recombinant Fusion Proteins ; metabolism ; physiology ; Virulence Factors ; metabolism ; physiology

Bronchopulmonary dysplasia (BPD) has the main manifestations of pulmonary edema in the early stage and characteristic alveolar obstruction and microvascular dysplasia in the late stage, which may be caused by structural and functional destruction of the lung epithelial barrier. The Claudin family is the main component of tight junction and plays an important role in regulating the permeability of paracellular ions and solutes. Claudin-18 is the only known tight junction protein solely expressed in the lung. The lack of Claudin-18 can lead to barrier dysfunction and impaired alveolar development, and the knockout of Claudin-18 can cause characteristic histopathological changes of BPD. This article elaborates on the important role of Claudin-18 in the development and progression of BPD from the aspects of lung epithelial permeability, alveolar development, and progenitor cell homeostasis, so as to provide new ideas for the pathogenesis and clinical treatment of BPD.
Bronchopulmonary Dysplasia/etiology* ; Claudin-3 ; Claudins/genetics* ; Humans ; Infant ; Infant, Newborn ; Infant, Premature ; Lung ; Tight Junctions

OBJECTIVETo investigate the changes of intestinal mucosal tight junction proteins claudin-1, -3, -4 in patients with irritable bowel syndrome (IBS), and elucidate its possible role in the bowel evacuation habit changes and formation in these patients.

METHODSWestern blotting was employed to determine tight junction protein claudin-1,-3,-4 levels in the intestinal mucosa of patients in the control group, diarrhea-predominant IBS (D-IBS) group and constipation-predominant IBS (C-IBS) group.

RESULTSCompared with the control group, D-IBS patients showed significantly decreased claudin-1 protein levels in both the small intestinal and colonic mucosae (P<0.05), whereas C-IBS patients had significantly elevated claudin-1 protein levels (P<0.05). No significant difference was found in claudin-3 protein expression in the both small intestinal and colonic mucosae between the D-IBS group and the control group (P>0.05), but claudin-3 protein level was shown to increase significantly in C-IBS patients (P<0.05). Claudin-4 protein followed the same pattern of alteration as claudin-1.

CONCLUSIONDown-regulated claudin-1 and -4 expressions can be associated with bowel evacuation habit changes and formation in patients with D-IBS, but up-regulated claudin-1, -3 and -4 expressions may relate to such bowel changes in patients with C-IBS.

Adolescent ; Adult ; Aged ; Animals ; Blotting, Western ; Case-Control Studies ; Claudin-1 ; Claudin-3 ; Claudin-4 ; Colon ; metabolism ; pathology ; Female ; Gene Expression Regulation ; Humans ; Intestinal Mucosa ; metabolism ; pathology ; Irritable Bowel Syndrome ; metabolism ; pathology ; Male ; Membrane Proteins ; metabolism ; Middle Aged ; Tight Junctions ; metabolism ; Young Adult

Ischemic stroke results in the diverse phathophysiologies including blood brain barrier (BBB) disruption, brain edema, neuronal cell death, and synaptic loss in brain. Vitamin C has known as the potent anti-oxidant having multiple functions in various organs, as well as in brain. Dehydroascorbic acid (DHA) as the oxidized form of ascorbic acid (AA) acts as a cellular protector against oxidative stress and easily enters into the brain compared to AA. To determine the role of DHA on edema formation, neuronal cell death, and synaptic dysfunction following cerebral ischemia, we investigated the infarct size of ischemic brain tissue and measured the expression of aquaporin 1 (AQP-1) as the water channel protein. We also examined the expression of claudin 5 for confirming the BBB breakdown, and the expression of bcl 2 associated X protein (Bax), caspase-3, inducible nitric oxide synthase (iNOS) for checking the effect of DHA on the neurotoxicity. Finally, we examined postsynaptic density protein-95 (PSD-95) expression to confirm the effect of DHA on synaptic dysfunction following ischemic stroke. Based on our findings, we propose that DHA might alleviate the pathogenesis of ischemic brain injury by attenuating edema, neuronal loss, and by improving synaptic connection.
Aquaporins ; Aquaporin 1 ; Ascorbic Acid ; bcl-2-Associated X Protein ; Blood-Brain Barrier ; Brain ; Brain Edema* ; Brain Injuries ; Brain Ischemia* ; Caspase 3 ; Cell Death ; Claudin-5 ; Dehydroascorbic Acid* ; Edema ; Neurons ; Nitric Oxide Synthase Type II ; Oxidative Stress ; Post-Synaptic Density ; Stroke

PURPOSE: Claudin-4 has been reported to function as a paracellular sodium barrier and is one of the 3 major claudins expressed in lung alveolar epithelial cells. However, the possible role of claudin-4 in bronchial asthma has not yet been fully studied. In this study, we aimed to elucidate the role of claudin-4 in the pathogenesis of bronchial asthma. METHODS: We determined claudin-4 levels in blood from asthmatic patients. Moreover, using mice sensitized and challenged with OVA, as well as sensitized and challenged with saline, we investigated whether claudin-4 is involved in the pathogenesis of bronchial asthma. Der p1 induced the inflammatory cytokines in NHBE cells. RESULTS: We found that claudin-4 in blood from asthmatic patients was increased compared with that from healthy control subjects. Plasma claudin-4 levels were significantly higher in exacerbated patients than in control patients with bronchial asthma. The plasma claudin-4 level was correlated with eosinophils, total IgE, FEV1% pred, and FEV1/FVC. Moreover, lung tissues from the OVA-OVA mice showed significant increases in transcripts and proteins of claudin-4 as well as in TJ breaks and the densities of claudin-4 staining. When claudin-4 was knocked down by transfecting its siRNA, inflammatory cytokine expressions, which were induced by Der p1 treatment, were significantly increased. CONCLUSIONS: These findings thus raise the possibility that regulation of lung epithelial barrier proteins may constitute a therapeutic approach for asthma.
Animals ; Asthma ; Claudin-4 ; Claudins ; Cytokines ; Eosinophils ; Epithelial Cells ; Humans ; Immunoglobulin E ; Inflammation ; Lung ; Mice ; Ovum ; Plasma ; RNA, Small Interfering ; Sodium

No abstract available.
Breast ; Breast Neoplasms ; Claudins ; Estrogens