• Korean Journal of Clinical Laboratory Science
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• v.47 no.4
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• pp.267-272
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• 2015

'Tight junctions (TJ)' have recently been identified in the granular cell layer of the human epidermis, where they contribute to the normal adhesion between keratinocytes and to the physiologic barrier function of the epidermis. Among the TJ proteins in the epidermis, occludin is an important transmembrane protein, which is considered as a major component. The purpose of this study is to investigate whether regional variation exists in the expression of the tight junction protein occludin in normal human epidermis. Indirect immunofluorescence staining for occludin was performed with specimens taken from different areas of normal skin (4 from each of 7 different anatomical sites, including the scalp, face, posterior neck, upper arm, abdomen, lower back, and inner thigh). The degrees of the expression-intensity in each specimen were estimated with the reciprocals of positive end-point titer of occludin in an indirect immunofluorescence study. The highest degree expression-intensity of the TJ protein occludin among the different areas of normal epidermis was observed on the face and abdomen with a titer of 600 (p=0.001). The lowest intensity of expression of occludin was seen in the epidermis from the upper arm. Skin specimens from the scalp, neck, back, and leg demonstrated intermediate degrees of the expression in intensity. The expression of occludin in the skin samples obtained from different locations of the body showed a statistically significant variation. This suggests that there is a certain degree of regional variation in the expression-intensity of TJ protein 'occludin' in the human epidermis.

• Journal of Korean Neurosurgical Society
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• v.38 no.1
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• pp.12-15
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• 2005

Objective : Cerebral edema develops in the brain tumors by loosening of the endothelial tight junction. Tight junction[TJ] proteins, such as occludin and claudin bind adjacent cells tightly. Authors examine the expression rate of occludin in human brain tumors to evaluate the effect of altered expression of occludin on cerebral edema. Methods : Seventy surgical specimens stored at $-70^{\circ}C$ were used. It included 14 astrocytic tumors, 27 meningiomas, 12 scwannomas, 7 pituitary adenomas, 6 hemangioblastomas. and 4 craniopharyngiomas. After protein extraction, expression of occludin was investigated by Western blot analysis. The tumors were classified according to World Health Organization[WHO] classification. Results : The expression rates of occludin in brain tumors were : glioma [8/14=57.1%]. meningioma [16/27=59.3%], schwannoma [10/12=83.3%], pituitary adenoma [6/7=85.7%], hemangioblastoma [6/6=100%], and craniopharyngioma [3/4=75.0%]. The expression rate in glioma and meningioma was lower than other brain tumors. In gliomas, high grade tumor [1/4=25.0%] exhibited lower expression rate of occludin than low grade one [7/10=70.0%]. Conclusion : These results suggest that the expression of occludin is different among the various kinds of brain tumors. In gliomas, its expression is correlated with the histological grade. It may indicate that occludin plays a role in the development of edema in the brain tumors.

• Applied Microscopy
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• v.34 no.4
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• pp.231-239
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• 2004

Cerebral microvessel endothelial cells that form blood-brain barrier (BBB) have tight junction for maintaining brain homeostasis. Occludin, one of tight junction protein, is crucial for BBB function. $H_2O_2$ induced occludin changes and effects in bovine brain BBB endothelial cells were examined in this study. The decrease of transendothelial electrical resistance (TEER) by $H_2O_2$ was due to disruption of occludin localization. Cytotoxicity test revealed that $H_2O_2$ did not cause cell death below 1 mM $H_2O_2$ within 4 hr. $H_2O_2$ caused intermittent disruption and loss of occludin at tight junctions and occludin disappeared with dose dependent manner from tight junction in confocal laser microscopy. But Western blot revealed that the total amounts of occludin increased by $H_2O_2$ administration. Transmission electron microscopy revealed that the ultrastructure of tight junction was not changed by $H_2O_2$. These data suggest that functional disruption of BBB by $H_2O_2$ was due to the localized loss of occludin in tight junction, but the expression of occludin increased in order to compensate the disrupted function in BBB.

• Korean Journal of Environmental Biology
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• v.24 no.2 s.62
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• pp.166-171
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• 2006

To elucidate the effect of phytoestrogens on the prevention of neurodegenerative disease in postmenopausal women, the expression of occludin which build up the blood-brain barrier was examined in hippocampus following oral administration of estrogen (E2), genistein, diadzein or combination of genistein and diadzein in ovariectomized (OVX) female rats. E2 significantly increased occludin mRNA level in OVX rat hippocampus, suggesting that estrogen is a physiological regulator for structural integrity of the blood-brain barrier in hippocampus. Following isoflavone diet for 4 weeks, there was significant increase in occludin mRNA level in hippocampus, suggesting that isoflavone diet may be effective for protection of structural integrity of blood-brain barrier in hippocampus from degenerative changes in estrogen deficiency.

• Proceedings of the Korean Society of Embryo Transfer Conference
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• 2004.10a
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• pp.47-48
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• 2004

• Journal of Life Science
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• v.26 no.5
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• pp.531-536
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• 2016

We previously showed that NAD(P)H:quinone oxidoreductase 1 (NQO1) knockout (KO) mice exhibited spontaneous inflammation with markedly increased mucosal permeability in the gut, and that NQO1 is functionally associated with regulating tight junctions in the mucosal epithelial cells that govern the mucosal barrier. Here, we confirm the role of NQO1 in the formation of tight junctions by human colonic epithelial cells (HT29). We treated HT29 cells with a chemical inhibitor of NQO1 (dicumarol; 10 μM), and examined the effect on the transepithelial resistance of epithelial cells and the protein expression levels of ZO1 and occludin (two known regulators of tight junctions between gut epithelial cells). The dicumarol-induced inhibition of NQO1 markedly reduced transepithelial resistance (a measure of tight junctions) and decreased the levels of the tested tight junction proteins. In vivo, luminal injection of dicumarol significantly increased mucosal permeability and decreased ZO1 and occludin protein expression levels in mouse guts. However, in contrast to the previous report that the epithelial cells of NQO1 KO mice showed marked down-regulations of the transcripts encoding ZO1 and occludin, these transcript levels were not affected in dicumarol-treated HT29 cells. This result suggests that the NQO1-depedent regulation of tight junction molecules may involve multiple processes, including both transcriptional regulation and protein degradation processes such as those governed by the ubiquitination/proteasomal, and/or lysosomal systems.

• Korean Journal of Organic Agriculture
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• v.29 no.1
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• pp.125-136
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• 2021

In this study, a meta-analysis was performed to determine the correlation between the expression of tight junction protein in the intestine and the productivity of broiler chickens. A total of 9 papers were selected in which the result values consisted of the mean and standard deviation value, and the standardized mean difference was calculated to compare the mean of the control and treatment groups. A meta-regression test was conducted to determine the effect of each type of tight junction protein. The TJPs observed in each study were claudin1, claudin2, claudin3, occludin, ZO1, ZO2, etc., and the indicators to indicate the productivity of broilers were body weight gain (BWG), feed intake (FI), and feed conversion rate (FCR), average daily feed intake (ADFI), average daily gain (ADG), and feed/gain ratio (FPG). Although there are differences depending on the type of TJP, it was found that the change in expression level had a close effect on the productivity of broilers. In particular, occludin significantly correlated with body weight gain, feed intake, and feed conversion rate. Based on the results of this study, a study on a method to effectively increase the expression level of TJP is expected to contribute to improving the productivity of broilers and producing safe livestock products.

• Journal of Animal Science and Technology
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• v.64 no.3
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• pp.500-514
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• 2022

The blood-epididymis barrier (BEB) forms a unique microenvironment that is crucial for the maturation, protection, transport, and storage of spermatozoa in the epididymis. To characterize the function of tight junctions (TJs), which are constitutive components of the BEB, we determined the expression and localization of TJ proteins such as zonula occludens (ZO)-1, 2, and 3, occludin, and claudin3 (Cldn3) during postnatal development in the goat epididymis. To assess the expression patterns of TJ proteins in immature (3 months of age) and mature (14 months of age) goat epididymides, two different experimental methods were used including immunofluorescence labeling and western blotting. We show that, ZO-1, 2, and 3, and occludin, were strictly expressed and localized to the TJs of the goat epididymis, whereas Cldn3 was present in basolateral membranes as well as TJs. All TJ proteins examined were more highly expressed in the immature epididymis compared to levels in mature tissue. In conclusion, our study indicates that at least five TJ proteins, namely ZO-1, ZO-2, ZO-3, occludin, and Cldn3, are present in TJs, and the expression strength and pattern of TJ proteins tend to be age dependent in the goat epididymis. Together, these data suggest that the distinct expression patterns of TJ proteins are essential for regulating components of the luminal contents in the epididymal epithelium and for forming adequate luminal conditions that are necessary for the maturation, protection, transport, and storage of spermatozoa in the goat epididymis.

• Journal of the korean academy of Pediatric Dentistry
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• v.33 no.2
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• pp.181-191
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• 2006

NFI-C null mice demonstrated aberrant odontoblast differentiation and thus abnormal dentin formation while other tissues/organs in the body, including ameloblasts, appear to be unaffected and normal. However little is known about the mechanism of NFI-C function in odontoblast differentiation and dentin formation. Odontoblasts are tall, highly polarized cells that are responsible for formation and maintenance of the predentin and dentin. An indication of their polarity is the acquisition of specialized intercellular junctions. As preodontoblasts differentiate into odontoblasts, they are Joined and attached at the apical end by well developed terminal webs of cytoskeletal actins, and associated tight as well as adherent njunctions. In this study, in order to investigate if disruption of the NFI-C gene interferes with formation of a specific or other structural proteins of the intercellular junctions, we examined morphological characteristic of the aberrant odontoblast in NFI-C null mice using light and electron microscope. In addition, we determined the expression of major structural proteins of intercellular junctions, ZO-1 and occludin, during the differentiation of odontoblasts using immunohitochemistry. The results were as follows : 1. In light microscopy, abnormal odontoblasts of incisors of the NFI-C null mice were round in shape, lost their polarity, and trapped in osteodentin-like mineralized tissue. Mutant molars have relatively normal crowns, but short and abnormal differentiating adontoblasts in root formation area. 2. Electron microscopy of abnormal odontoblasts revealed the dissociation of the round osteoblast-like cells, the loss of their cellular polarity, and the absence of an intercellular junctional complex known as the tight junctions. 3. A mutant incisor showed labeling for ZO-1 at the proximal and distal ends of secreting ameloblasts, while staining for ZO-1 was not observed in the abnormal odontoblasts. 4. A normal incisor showed immunoreactivity for occludin in the differentiating odontoblasts. However, staining for occludin was not observed in the abnormal odontoblasts of mutant incisor. These results suggest that NFI-C gene causes dissociation of odontoblast and thus abberant odontoblast differentiation and abnormal dentin formation by interfering with the formation of intercellular junctions.

• 대한생식의학회:학술대회논문집
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• 2007.06a
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• pp.133-133
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• 2007