Quercetin Alleviates Lipopolysaccharide-Induced Cardiac Inflammation via Inhibiting Autophagy and Programmed Cell Death / 生物医学与环境科学（英文）

OBJECTIVE@#The aim of this study is to explore the potential modulatory role of quercetin against Endotoxin or lipopolysaccharide (LPS) induced septic cardiac dysfunction.@*METHODS@#Specific pathogen-free chicken embryos ( n = 120) were allocated untreated control, phosphate buffer solution (PBS) vehicle, PBS with ethanol vehicle, LPS (500 ng/egg), LPS with quercetin treatment (10, 20, or 40 nmol/egg, respectively), Quercetin groups (10, 20, or 40 nmol/egg). Fifteen-day-old embryonated eggs were inoculated with abovementioned solutions via the allantoic cavity. At embryonic day 19, the hearts of the embryos were collected for histopathological examination, RNA extraction, real-time polymerase chain reaction, immunohistochemical investigations, and Western blotting.@*RESULTS@#They demonstrated that the heart presented inflammatory responses after LPS induction. The LPS-induced higher mRNA expressions of inflammation-related factors (TLR4, TNFα, MYD88, NF-κB1, IFNγ, IL-1β, IL-8, IL-6, IL-10, p38, MMP3, and MMP9) were blocked by quercetin with three dosages. Quercetin significantly decreased immunopositivity to TLR4 and MMP9 in the treatment group when compared with the LPS group. Quercetin significantly decreased protein expressions of TLR4, IFNγ, MMP3, and MMP9 when compared with the LPS group. Quercetin treatment prevented LPS-induced increase in the mRNA expression of Claudin 1 and ZO-1, and significantly decreased protein expression of claudin 1 when compared with the LPS group. Quercetin significantly downregulated autophagy-related gene expressions (PPARα, SGLT1, APOA4, AMPKα1, AMPKα2, ATG5, ATG7, Beclin-1, and LC3B) and programmed cell death (Fas, Bcl-2, CASP1, CASP12, CASP3, and RIPK1) after LPS induction. Quercetin significantly decreased immunopositivity to APOA4, AMPKα2, and LC3-II/LC3-I in the treatment group when compared with the LPS group. Quercetin significantly decreased protein expressions of AMPKα1, LC3-I, and LC3-II. Quercetin significantly decreased the protein expression to CASP1 and CASP3 by immunohistochemical investigation or Western blotting in treatment group when compared with LPS group.@*CONCLUSION@#Quercetin alleviates cardiac inflammation induced by LPS through modulating autophagy, programmed cell death, and myocardiocytes permeability.

Zhizhu Decoction Alleviates Intestinal Barrier Damage via Regulating SIRT1/FoxO1 Signaling Pathway in Slow Transit Constipation Model Mice / 中国结合医学杂志

OBJECTIVE@#To explore the possible effects and mechanism of Zhizhu Decoction (ZZD) on the pathophysiology of slow transit constipation (STC).@*METHODS@#A total of 54 C57BL/6 mice was randomly divided into the following 6 groups by a random number table, including control, STC model (model), positive control, and low-, medium- and high-doses ZZD treatment groups (5, 10, 20 g/kg, namely L, M-, and H-ZZD, respectively), 9 mice in each group. Following 2-week treatment, intestinal transport rate (ITR) and fecal water content were determined, and blood and colon tissue samples were collected. Hematoxylin-eosin and periodic acid-Schiff staining were performed to evaluate the morphology of colon tissues and calculate the number of goblet cells. To determine intestinal permeability, serum levels of lipopolysaccharide (LPS), low-density lipoprotein (LDL) and mannose were measured using enzyme-linked immunosorbent assay (ELISA). Western blot analysis was carried out to detect the expression levels of intestinal tight junction proteins zona-occludens-1 (ZO-1), claudin-1, occludin and recombinant mucin 2 (MUC2). The mRNA expression levels of inflammatory cytokines including tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6, IL-4, IL-10 and IL-22 were determined using reverse transcription-quantitative reverse transcription reaction. Colon indexes of oxidative stress were measured by ELISA, and protein expression levels of colon silent information regulator 1/forkhead box O transcription factor 1 (SIRT1/FoxO1) antioxidant signaling pathway were detected by Western blot.@*RESULTS@#Compared with the model group, ITR and fecal moisture were significantly enhanced in STC mice in the M-ZZD and H-ZZD groups (P<0.01). Additionally, ZZD treatment notably increased the thickness of mucosal and muscular tissue, elevated the number of goblet cells in the colon of STC mice, reduced the secretion levels of LPS, LDL and mannose, and upregulated ZO-1, claudin-1, occludin and MUC2 expressions in the colon in a dose-dependent manner, compared with the model group (P<0.05 or P<0.01). In addition, ZZD significantly attenuated intestinal inflammation and oxidative stress and activated the SIRT1/FoxO1 signaling pathway (P<0.05 or P<0.01).@*CONCLUSION@#ZZD exhibited beneficial effects on the intestinal system of STC mice and alleviated intestinal inflammation and oxidative stress via activating SIRT1/FoxO1 antioxidant signaling pathway in the colon.

Role of Nrf2/GPX4 mediated ferroptosis in intestinal injury in sepsis / 中华危重病急救医学

OBJECTIVE@#To investigate whether ferroptosis exists in sepsis induced intestinal injury, and to verify the association between ferroptosis in sepsis induced intestinal injury and intestinal inflammation and barrier function by stimulating and inhibiting the nuclear factor E2-related factor 2/glutathione peroxidase 4 (Nrf2/GPX4) pathway.@*METHODS@#Forty-eight SPF grade male Sprague-Darvley (SD) rats with a body weight of 220-250 g were divided into sham operation group (Sham group), sepsis group (CLP group), sepsis+iron chelating agent deferoxamine (DFO) group (CLP+DFO group) and sepsis+ferroptosis inducer Erastin group (CLP+Erastin group) using a random number table method, with 12 rats in each group. The sepsis model was established by cecal ligation and puncture (CLP). The Sham group was only performed with abdominal opening and closing operations. After modeling, the CLP+DFO group received subcutaneous injection of 20 mg/kg of DFO, the CLP+Erastin group was intraperitoneally injected with 20 mg/kg of Erastin. Each group received subcutaneous injection of 50 mg/kg physiological saline for fluid resuscitation after surgery, and the survival status of the rats was observed 24 hours after surgery. At 24 hours after model establishment, 6 rats in each group were selected. First, live small intestine tissue was taken for observation of mitochondrial morphology in smooth muscle cells under transmission electron microscopy and determination of reactive oxygen species (ROS). Then, blood was collected from the abdominal aorta and euthanized. The remaining 6 rats were sacrificed after completing blood collection from the abdominal aorta, and then small intestine tissue was taken. Western blotting was used to detect the expression of intestinal injury markers such as Claudin-1 and ferroptosis related proteins GPX4 and Nrf2. Observe the pathological changes of small intestine tissue using hematoxylin-eosin (HE) staining and complete Chiu score; Detection of tumor necrosis factor-α (TNF-α), interleukins (IL-1β, IL-6) levels in serum using enzyme-linked immunosorbent assay (ELISA). The levels of serum iron ions (Fe3+), malondialdehyde (MDA), and D-lactate dehydrogenase (D-LDH) were measured.@*RESULTS@#(1) Compared with the Sham group, the 24-hour survival rate of rats in the CLP group and CLP+Erastin group significantly decreased (66.7%, 50.0% vs. 100%, both P < 0.05), while there was no significant difference in the CLP+DFO group (83.3% vs. 100%, P = 0.25). (2) Western blotting results showed that compared with the Sham group, the expressions of GPX4 and Claudin-1 in the small intestine tissue of the CLP group, CLP+DFO group, and CLP+Erastin group decreased significantly, while the expression of Nrf2 increased significantly (GPX4/β-actin: 0.56±0.02, 1.03±0.01, 0.32±0.01 vs. 1.57±0.01, Claudin-1/β-actin: 0.60±0.04, 0.96±0.07, 0.41±0.01 vs. 1.40±0.01, Nrf2/β-actin: 0.88±0.02, 0.72±0.01, 1.14±0.01 vs. 0.43±0.02, all P < 0.05). Compared with the CLP group, the expressions of GPX4 and Claudin-1 were significantly increased in the CLP+DFO group, while the expression of Nrf2 was significantly reduced. In the CLP+Erastin group, the expressions of GPX4 and Claudin-1 further decreased, while the expression of Nrf2 further increased (all P < 0.05). (3) Under the light microscope, compared with the Sham group, the CLP group, CLP+DFO group, and CLP+Erastin group showed structural disorder in the small intestinal mucosa and submucosal tissue, significant infiltration of inflammatory cells, and destruction of glandular and villous structures. The Chui score was significantly higher (3.25±0.46, 2.00±0.82, 4.50±0.55 vs. 1.25±0.45, all P < 0.05). (4) Under transmission electron microscopy, compared with the Sham group, the mitochondria in the other three groups of small intestinal smooth muscle cells showed varying degrees of volume reduction, increased membrane density, and reduced or disappeared cristae. The CLP+Erastin group showed the most significant changes, while the CLP+DFO group showed only slight changes in mitochondrial morphology. (5) Compared to the Sham group, the CLP group, CLP+DFO group, and CLP+Erastin group had serum levels of TNF-α, IL-1β, IL-6, MDA, D-LDH, and ROS in small intestine tissue were significantly increased, while the serum Fe3+ content was significantly reduced [TNF-α (ng/L): 21.49±1.41, 17.24±1.00, 28.66±2.72 vs. 14.17±1.24; IL-1β (ng/L): 108.40±3.09, 43.19±8.75, 145.70±11.00 vs. 24.50±5.55; IL-6 (ng/L): 112.50±9.76, 45.90±6.52, 151.80±9.38 vs. 12.89±6.11; MDA (μmol/L): 5.61±0.49, 3.89±0.28, 8.56±1.17 vs. 1.86±0.41; D-LDH (kU/L): 39.39±3.22, 25.38±2.34, 53.29±10.53 vs. 10.79±0.52; ROS (fluorescence intensity): 90 712±6 436, 73 278±4 775, 110 913±9 287 vs. 54 318±2 226; Fe3+ (μmol/L): 22.19±1.34, 34.05±1.94, 12.99±1.08 vs. 51.74±11.07; all P < 0.05]. Compared with CLP group, the levels of TNF-α, IL-1β, IL-6, MDA, D-LDH and ROS in CLP+Erastin group were further increased, and the content of Fe3+ was further decreased, the CLP+DFO group was the opposite (all P < 0.05).@*CONCLUSIONS@#Ferroptosis exists in the intestinal injury of septic rats, and stimulating or inhibiting ferroptosis through the Nrf2/GPX4 pathway can effectively intervene in the inflammatory state and intestinal mechanical barrier of the body.

Effects of Buyang Huanwu Decoction on Intestinal Barrier, Intestinal Flora, and Trimethylamine Oxide in Rats with Heart Failure / 中国结合医学杂志

OBJECTIVE@#To explore the mechanisms of Buyang Huanwu Decoction (BYHWD) modulating the gut microbiome and trimethylamine oxide (TAMO) to exert cardioprotective effects.@*METHODS@#Ligation of the left anterior descending coronary artery was performed in rats to induce heart failure (HF). Except for the sham-operation group (n=10), 36 operation-induced models were randomized into 3 groups using a random number table (n=12 in each group): the model group, the BYHWD group (15.02 g/kg BYHWD), and the positive group (4.99 g/kg metoprolol succinate). After 4-week treatment (once daily by gavage), echocardiography was applied to evaluate the cardiac function and the Tei index (the ratio of ventricular isovolumic contraction time (IVCT) and isovolumic diastolic time (IVRT) to ejection time (ET)) was calculated; hematoxylin-eosin (HE) staining was observed to characterize the pathology of the myocardium and small intestinal villi. D-lactic acid was detected by an enzyme-linked immunosorbent assay (ELISA). Expressions of occludin, claudin-1, and zonula occludens (ZO-1) were detected by Western blot. 16S ribosomal ribonucleic acid (16S rRNA) sequencing was used to explore the changes in the intestinal flora. TMAO was detected via liquid chromatography-tandem mass spectrometry (LC-MS/MS).@*RESULTS@#In the echocardiography, the Tei index was considerably lower in the positive and BYHWD groups compared with the model group (P<0.05). Besides, BYHWD improved the pathology of myocardium and small intestine of HF rats and lowered the D-lactic acid content in the serum, when compared with the model group (P<0.05). BYHWD also improved the expression of occludin and claudin-1 (P<0.05); in the gut microbiota analysis, BYHWD slowed down modifications in the structure distribution of gut microbiota and regulated the diversity of intestinal flora in HF rats. The content of TMAO in the serum was significantly lowered by BYWHT compared with the model group (P<0.05).@*CONCLUSION@#BYHWD may delay progression of HF by enhancing the intestinal barrier structure, and regulating intestinal flora and TAMO.

Zuogui Jiangtang Qinggan Prescription promotes recovery of intestinal mucosal barrier in mice with type 2 diabetes mellitus and nonalcoholic fatty liver disease by improving intestinal flora homeostasis / 中国中药杂志

This study aimed to investigate the recovery effect of Zuogui Jiangtang Qinggan Prescription on intestinal flora homeostasis control and intestinal mucosal barrier in type 2 diabetes mellitus(T2DM) with nonalcoholic fatty liver disease(NAFLD) induced by a high-fat diet. NAFLD was established in MKR transgenic mice(T2DM mice) by a high-fat diet(HFD), and subsequently treated for 8 weeks with Zuogui Jiangtang Qinggan Prescription(7.5, 15 g·kg~(-1)) and metformin(0.067 g·kg~(-1)). Triglyceride and liver function were assessed using serum. The hematoxylin-eosin(HE) staining and Masson staining were used to stain the liver tissue, while HE staining and AB-PAS staining were used to stain the intestine tissue. 16S rRNA sequencing was utilized to track the changes in the intestinal flora of the mice in each group. Polymerase chain reaction(PCR) and immunofluorescence were used to determine the protein and mRNA expression levels of ZO-1, Occludin, and Claudin-1. The results demonstrated that Zuogui Jiangtang Qinggan Prescription increased the body mass of T2DM mice with NAFLD and decreased the hepatic index. It down-regulated the serum biomarkers of liver function and dyslipidemia such as alanine aminotransferase(ALT), aspartate transaminase(AST), and triglycerides(TG), increased insulin sensitivity, and improved glucose tolerance. According to the results of 16S rRNA sequencing, the Zuogui Jiangtang Qinggan Prescription altered the composition and abundance of the intestinal flora, increasing the relative abundances of Muribaculaceae, Lactobacillaceae, Lactobacillus, Akkermansia, and Bacteroidota and decreasing the relative abundances of Lachnospiraceae, Firmicutes, Deslfobacteria, Proteobacteria, and Desulfovibrionaceae. According to the pathological examination of the intestinal mucosa, Zuogui Jiangtang Qinggan Prescritpion increased the expression levels of the tight junction proteins ZO-1, Occludin, and Claudin-1, promoted intestinal mucosa repair, protected intestinal villi, and increased the height of intestinal mucosa villi and the number of goblet cells. By enhancing intestinal mucosal barrier repair and controlling intestinal microbiota homeostasis, Zuogui Jiangtang Qinggan Prescription reduces intestinal mucosal damage induced by T2DM and NAFLD.

Claudin-1 and Claudin-3 as Molecular Regulators of Myelination in Leukoaraiosis Patients

OBJECTIVES: Leukoaraiosis is described as white matter lesions that are associated with cognitive dysfunction, neurodegenerative disorders, etc. Myelin depletion is a salient pathological feature of, and the loss of oligodendrocytes is one of the most robust alterations evident in, white matter degeneration. Recent studies have revealed that claudin proteins are aberrantly expressed in leukoaraiosis and regulate oligodendrocyte activity. However, the roles of claudin-1 and claudin-3 in oligodendrocytes and leukoaraiosis are still not well-defined. METHODS: Quantitative polymerase chain reaction was used to measure the expression of claudin-1 (CLDN1), claudin-3 (CLDN3), and myelinogenesis-related genes such as myelin basic protein (MBP), proteolipid protein (PLP), oligodendrocyte transcription factor 2 (OLIG2), and SRY-box transcription factor 10 (SOX10) in leukoaraiosis patients (n=122) and healthy controls (n=122). The expression of claudin-1 and claudin-3 was either ectopically silenced or augmented in Oli-neu oligodendrocytes, and colony formation, apoptosis, and migration assays were performed. Finally, the expression of myelin proteins was evaluated by western blotting. RESULTS: Our results revealed that in addition to SOX10, the expression levels of claudin-1, claudin-3, and myelinogenesis-related proteins were prominently downregulated in leukoaraiosis patients, compared to those in healthy controls. Furthermore, the growth and migration of Oli-neu cells were downregulated upon silencing claudin-1 or claudin-3. However, the overexpression of claudin-1 or claudin-3 resulted in the reduction of the degree of apoptosis in Oli-neu cells. In addition, claudin-1 and claudin-3 promoted the expression of MBP, OLIG2, PLP, and SOX10 at the translational level. CONCLUSION: Our data has demonstrated that the abnormal expression of claudin-1 and claudin-3 regulates the pathological progression of leukoaraiosis by governing the viability and myelination of oligodendrocytes. These findings provide novel insights into the regulatory mechanisms underlying the roles of claudin-1 and claudin-3 in leukoaraiosis.

Particulate Matter 2.5 Causes Deficiency in Barrier Integrity in Human Nasal Epithelial Cells

PURPOSE: The effect of air pollution-related particulate matter (PM) on epithelial barrier function and tight junction (TJ) expression in human nasal mucosa has not been studied to date. This study therefore aimed to assess the direct impact of PM with an aerodynamic diameter less than 2.5 μm (PM2.5) on the barrier function and TJ molecular expression of human nasal epithelial cells. METHODS: Air-liquid interface cultures were established with epithelial cells derived from noninflammatory nasal mucosal tissue collected from patients undergoing paranasal sinus surgery. Confluent cultures were exposed to 50 or 100 µg/mL PM2.5 for up to 72 hours, and assessed for 1) epithelial barrier integrity as measured by transepithelial resistance (TER) and permeability of fluorescein isothiocyanate (FITC) 4 kDa; 2) expression of TJs using real-time quantitative polymerase chain reaction and immunofluorescence staining, and 3) proinflammatory cytokines by luminometric bead array or enzyme-linked immunosorbent assay. RESULTS: Compared to control medium, 50 and/or 100 µg/mL PM2.5-treatment 1) significantly decreased TER and increased FITC permeability, which could not be restored by budesonide pretreatment; 2) significantly decreased the expression of claudin-1 messenger RNA, claudin-1, occludin and ZO-1 protein; and 3) significantly increased production of the cytokines interleukin-8, TIMP metallopeptidase inhibitor 1 and thymic stromal lymphopoietin. CONCLUSIONS: Exposure to PM2.5 may lead to loss of barrier function in human nasal epithelium through decreased expression of TJ proteins and increased release of proinflammatory cytokines. These results suggest an important mechanism of susceptibility to rhinitis and rhinosinusitis in highly PM2.5-polluted areas.

NFATC3–PLA2G15 Fusion Transcript Identified by RNA Sequencing Promotes Tumor Invasion and Proliferation in Colorectal Cancer Cell Lines / Journal of the Korean Cancer Association, 대한암학회지

PURPOSE: This study was designed to identify novel fusion transcripts (FTs) and their functional significance in colorectal cancer (CRC) lines. MATERIALS AND METHODS: We performed paired-end RNA sequencing of 28 CRC cell lines. FT candidates were identified using TopHat-fusion, ChimeraScan, and FusionMap tools and further experimental validation was conducted through reverse transcription-polymerase chain reaction and Sanger sequencing. FT was depleted in human CRC line and the effects on cell proliferation, cell migration, and cell invasion were analyzed. RESULTS: One thousand three hundred eighty FT candidates were detected through bioinformatics filtering. We selected six candidate FTs, including four inter-chromosomal and two intrachromosomal FTs and each FT was found in at least one of the 28 cell lines. Moreover, when we tested 19 pairs of CRC tumor and adjacent normal tissue samples, NFATC3–PLA2G15 FT was found in two. Knockdown of NFATC3–PLA2G15 using siRNA reduced mRNA expression of epithelial–mesenchymal transition (EMT) markers such as vimentin, twist, and fibronectin and increased mesenchymal–epithelial transition markers of E-cadherin, claudin-1, and FOXC2 in colo-320 cell line harboring NFATC3–PLA2G15 FT. The NFATC3–PLA2G15 knockdown also inhibited invasion, colony formation capacity, and cell proliferation. CONCLUSION: These results suggest that that NFATC3–PLA2G15 FTs may contribute to tumor progression by enhancing invasion by EMT and proliferation.

Effects of Vitamin D Receptor on Mucosal Barrier Proteins in Colon Cells under Hypoxic Environment / 中国医学科学院学报

To investigate the expressions of mucosal barrier proteins in colon cell line DLD-1 under hypoxic environment and its mechanism. Methods After DLD-1 cells were treated separately with hypoxia(l% O),vitamin D(100 nmol/L),or vitamin D plus hypoxia for 48 hours,the expressions of vitamin D receptor(VDR),tight junction proteins zonula occludens-1(ZO-1),occludin,Claudin-1,and adherent junction protein(E-cadherin)were determined by Western blot.Stable VDR knock-down(Sh-VDR)DLD-1 cell line and control DLD-1 cell line were established by lentivirus package technology and the protein expressions after hypoxia treatment were detected. Results Compared with control group,the expressions of occludin,Claudin-1,and VDR increased significantly after hypoxia treatment(all <0.001).In addition to the protein expressions of occludin,Claudin-1 and VDR,the expressions of ZO-1 and E-cadherin were also obviously higher in vitamin D plus hypoxia group than in single vitamin D treatment group(all <0.001).After hypoxia treatment,Sh-VDR cell line showed significantly decreased expressions of ZO-1(<0.001),occludin(<0.05),Claudin-1(<0.01)and E-cadherin(<0.001)when compared with untreated Sh-VDR cell line. Conclusion VDR acts as a regulator for the expressions of intestinal mucosal barrier proteins under hypoxia environment in DLD-1 colon cell line,indicating that VDR pathway may be another important protective mechanism for gut barrier in low-oxygen environment.

Comment on “Prognostic Role of Claudin-1 Immunohistochemistry in Malignant Solid Tumors: A Meta-Analysis”

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Prognostic Role of Claudin-1 Immunohistochemistry in Malignant Solid Tumors: A Meta-Analysis

BACKGROUND: Although the correlation between low claudin-1 expression and worse prognosis has been reported, details on the prognostic implications of claudin-1 expression in various malignant tumors remain unclear. The present study aimed to elucidate the prognostic roles of claudin- 1 immunohistochemistry (IHC) in various malignant tumors through a meta-analysis. METHODS: The study included 2,792 patients from 22 eligible studies for assessment of the correlation between claudin-1 expression and survival rate in various malignant tumors. A subgroup analysis based on the specific tumor and evaluation criteria of claudin-1 IHC was conducted. RESULTS: Low claudin-1 expression was significantly correlated with worse overall survival (OS) (hazard ratio [HR], 1.851; 95% confidence interval [CI], 1.506 to 2.274) and disease-free survival (DFS) (HR, 2.028; 95% CI, 1.313 to 3.134) compared to high claudin-1 expression. Breast, colorectal, esophageal, gallbladder, head and neck, and lung cancers, but not cervical, liver or stomach cancers, were significantly correlated with worse OS. Breast, colorectal, esophageal, and thyroid cancers with low claudin-1 expression were associated with poorer DFS. In the lower cut-off subgroup (< 25.0%) with respect to claudin-1 IHC, low claudin-1 expression was significantly correlated with worse OS and DFS. CONCLUSIONS: Taken together, low claudin-1 IHC expression is significantly correlated with worse survival in various malignant tumors. More detailed criteria for claudin-1 IHC expression in various malignant tumors are needed for application in daily practice.

Protease-Activated Receptors 2-Antagonist Suppresses Asthma by Inhibiting Reactive Oxygen Species-Thymic Stromal Lymphopoietin Inflammation and Epithelial Tight Junction Degradation

PURPOSE: Protease-activated receptor 2 (PAR2) reportedly triggers the immune response in allergic asthma. We aimed to investigate the mechanism on allergic inflammation mediated by PAR2. METHODS: Human lung epithelial cells (A549 cells) were used for in vitro, and the German cockroach extract (GCE)-induced mouse model was developed for in vivo studies. RESULTS: In A549 cells, the levels of reactive oxygen species (ROS) and thymic stromal lymphopoietin (TSLP) were significantly increased by GCE treatment, but were suppressed by PAR2-antagonist (PAR2-ant) or N-acetylcysteine (NAC) treatment. Claudin-1 was degraded by GCE, and was restored by PAR2-ant or NAC in the cells. In the mouse model, the clinical appearance including bronchial hyperresponsiveness, bronchoalveolar lavage fluid analysis and total immunoglobulin E were significantly suppressed by PAR2-ant or NAC. Moreover, TSLP levels in the lung were suppressed by the same treatments in the lung. Claudin-1 was also degraded by GCE, and was restored by PAR2-ant or NAC. CONCLUSIONS: ROS generation and epidermal tight junction degradation are triggered by protease, followed by the induction of TSLP in allergic asthma. Our findings could suggest that PAR2-ant or anti-oxidants could be considered for allergic diseases as preventive alternatives.

Comparison of Tight Junction Protein-Related Gene mRNA Expression Levels between Male and Female Gastroesophageal Reflux Disease Patients

BACKGROUND/AIMS: Male predominance has been observed in the erosive reflux disease (ERD), but reverse finding in nonerosive reflux disease (NERD). This suggests sex-specific medicine approach is needed but its mechanism is remained to be elucidated. We aimed to compare clinical characteristics and mRNA expression levels of tight junction-related proteins between male and female gastroesophageal reflux disease (GERD). METHODS: Sixteen healthy controls, 45 ERD, and 14 NERD patients received upper endoscopies and completed questionnaires. Quantitative real-time polymerase chain reactions of occludin (OCLN), zonal occludens (ZO) 1, claudin-1 (CLDN1) and claudin-4 (CLDN4), and neurokinin 1 receptor (NK1R) were performed in the distal esophageal mucosal specimen. These results were analyzed by sex. RESULTS: Female GERD patients were affected more by reflux symptoms than males. The impairment of overall quality of life was more prominent in female patients with reflux symptoms than male patients (5.6±0.2 vs 4.9±0.6, p=0.009). The levels of OCLN mRNA expression were significantly lower in the male ERD group. On the other hand, those of CLDN1, CLDN4, and NK1R except ZO-1 were significantly higher in the male ERD group. CONCLUSIONS: We demonstrated that female ERD/NERD patients were affected more by GERD and male ERD patients showed significant changes of tight junction protein mRNA expression levels.

Inflammation, Impaired Motility, and Permeability in a Guinea Pig Model of Postoperative Ileus

BACKGROUND/AIMS: Postoperative ileus (POI) is characterized by impaired propulsive function of the gastrointestinal tract after surgery. Although inflammation is considered to be an important pathogenesis of POI, significant data are lacking. We aim to correlate the recovery time of postoperative dysmotility with that of inflammation and mucosal permeability. METHODS: An experimental POI model of guinea pig was used. Contractile activity of the circular muscle of the stomach, jejunum, ileum, and proximal colon was measured through a tissue bath study. Inflammatory cells were counted, and the expression of calprotectin and tryptase were analyzed. The expression of protease-activated receptor 2 (PAR-2), claudin-1, and claudin-2 were analyzed with immunofluorescence. RESULTS: The small bowel and colon showed decreased contractile amplitude in the POI groups compared to control. In contrast to the colon, the contractile amplitude of the small bowel significantly recovered in the POI group at 6 hours after the operation compared to the control group. Inflammation was highly significant in the POI groups compared to the control and sham groups, especially in the colon. Immunofluorescence showed increased PAR-2 expression in the POI groups compared to sham. The decreased claudin-1 expression and increased claudin-2 expression may suggest increased mucosal permeability of the small bowel and colon in the POI groups. CONCLUSIONS: Increased inflammation and mucosal permeability may play an important role in the differential recovery stages in POI. These data may provide further insights into the pathophysiology and potential new therapeutic prospects of POI.

Additive Effects of Rebamipide Plus Proton Pump Inhibitors on the Expression of Tight Junction Proteins in a Rat Model of Gastro-Esophageal Reflux Disease

BACKGROUND/AIMS: The aim of this study was to investigate the effects of rebamipide on tight junction proteins in the esophageal mucosa in a rat model of gastroesophageal reflux disease (GERD). METHODS: GERD was created in rats by tying the proximal stomach. The rats were divided into a control group, a proton pump inhibitor (PPI) group, and a PPI plus rebamipide (PPI+R) group. Pantoprazole (5 mg/kg) was administered intraperitoneally to the PPI and PPI+R groups. An additional dose of rebamipide (100 mg/kg) was administered orally to the PPI+R group. Mucosal erosions, epithelial thickness, and leukocyte infiltration into the esophageal mucosa were measured in isolated esophagi 14 days after the procedure. A Western blot analysis was conducted to measure the expression of claudin-1, -3, and -4. RESULTS: The mean surface area of mucosal erosions, epithelial thickness, and leukocyte infiltration were lower in the PPI group and the PPI+R group than in the control group. Western blot analysis revealed that the expression of claudin-3 and -4 was significantly higher in the PPI+R group than in the control group. CONCLUSIONS: Rebamipide may exert an additive effect in combination with PPI to modify the tight junction proteins of the esophageal mucosa in a rat model of GERD. This treatment might be associated with the relief of GERD symptoms.

Rat prostate glandular epithelial cells cultured in vitro and their barrier function / 中华男科学杂志

<p><b>OBJECTIVE</b>To culture rat prostate glandular epithelial cells and study their barrier functions in vitro.</p><p><b>METHODS</b>Rat prostate glandular epithelial cells were cultured in vitro. The expression of the tight junction protein claudin-1 was determined by immunohistochemistry, the structure and composition of the epithelial cells observed under the inverted microscope and transmission electron microscope. The transepithelial electrical resistances (TEERs) were monitored with the Millicell system. The permeability of the prostate glandular epithelial cells was assessed by the phenol red leakage test.</p><p><b>RESULTS</b>Compact monolayer cell structures were formed in the prostate glandular epithelial cells cultured in vitro. Immunohistochemistry showed the expression of the tight junction protein claudin-1 and transmission electron microscopy confirmed the formation of tight junctions between the adjacent glandular epithelial cells. The TEERs in the cultured prostate glandular epithelial cells reached the peak of about (201.3 ± 3.5) Ω/cm2 on the 8th day. The phenol red leakage test manifested a decreased permeability of the cell layers with the increase of TEERs.</p><p><b>CONCLUSION</b>The structure and function of rat prostate glandular epithelial cells are similar to those of brain capillary endothelial cells, retinal capillary endothelial cells, and intestinal epithelial cells. In vitro cultured prostate glandular epithelial cells have the barrier function and can be used as a model for the study of blood prostate barrier in vitro.</p>

Claudin-1, -2, -4, and -5: comparison of expression levels and distribution in equine tissues

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.

High-fat Diet Accelerates Intestinal Tumorigenesis Through Disrupting Intestinal Cell Membrane Integrity

BACKGROUND: Excess energy supply induces chronic low-grade inflammation in association with oxidative stress in various tissues including intestinal epithelium. The objective of this study was to investigate the effect of high-fat diet (HFD) on intestinal cell membrane integrity and intestinal tumorigenesis in ApcMin/+ mice. METHODS: Mice were fed with either normal diet (ND) or HFD for 12 weeks. The number of intestinal tumors were counted and biomarkers of endotoxemia, oxidative stress, and inflammation were determined. Changes in intestinal integrity was measured by fluorescein isothiocyanate (FITC)-dextran penetration and membrane gap junction protein expression. RESULTS: HFD group had significantly higher number of tumors compared to ND group (P < 0.05). Blood total antioxidant capacity was lower in HFD group, while colonic 8-hydroxy-2'-deoxyguanosine level, a marker of oxidative damage, was higher in HFD group compared to that of ND group (P < 0.05). The penetration of FITC-dextran was substantially increased in HFD group (P < 0.05) while the expressions of membrane gap junction proteins including zonula occludens-1, claudin-1, and occludin were lower in HFD group (P < 0.05) compared to those in ND group. Serum concentration of lipopolysaccharide (LPS) receptor (CD14) and colonic toll-like receptor 4 (a LPS receptor) mRNA expression were significantly higher in HFD group than in ND group (P < 0.05), suggesting that significant endotoxemia may occur in HFD group due to the increased membrane permeability. Serum interleukin-6 concentration and myeloperoxidase activity were also higher in HFD group compared to those of ND group (P < 0.05). CONCLUSIONS: HFD increases oxidative stress disrupting intestinal gap junction proteins, thereby accelerating membrane permeability endotoxemia, inflammation, and intestinal tumorigenesis.

Changes in expression of Slingshot protein in hypoxic human intestinal epithelial cell and its relation with barrier function of the cells / 中华烧伤杂志

<p><b>OBJECTIVE</b>To study the effect of hypoxia on Slingshot protein expression in human intestinal epithelial cell and its relation with changes in barrier function of the cells.</p><p><b>METHODS</b>The human intestinal epithelial cell line Caco-2 was used to reproduce monolayer-cells. One portion of the monolayer-cell specimens were divided into six parts according to the random number table, and they were respectively exposed to hypoxia for 0 (without hypoxia), 1, 2, 6, 12, and 24 h. Transepithelial electrical resistance (TER) was determined with an ohmmeter. Another portion of the monolayer-cell specimens were exposed to hypoxia as above. Western blotting was used to detect the protein expressions of zonula occludens 1 (ZO-1), occludin, claudin-1, Slingshot-1, Slingshot-2, and Slingshot-3. The remaining portion of the monolayer-cell specimens were also exposed to hypoxia as above. The content of fibrous actin (F-actin) and globular actin (G-actin) was determined by fluorescence method. The sample number of above-mentioned 3 experiments was respectively 10, 10, and 18 at each time point. Data were processed with one-way analysis of variance and Dunnett test.</p><p><b>RESULTS</b>(1) Compared with that of cells exposed to hypoxia for 0 h, TER of cells exposed to hypoxia for 1 to 24 h was significantly reduced (P values below 0.01). (2) Compared with those of cells exposed to hypoxia for 0 h (all were 1.00), the protein expressions of ZO-1, occludin, and claudin-1 of cells exposed to hypoxia for 1 to 24 h were generally lower, especially those of cells exposed to hypoxia for 12 h or 24 h (respectively 0.69 ± 0.20, 0.47 ± 0.15, and 0.47 ± 0.22, P<0.05 or P<0.01). Compared with those of cells exposed to hypoxia for 0 h, the protein expressions of Slingshot-1 and Slingshot-3 of cells exposed to hypoxia for 1 to 24 h were not obviously changed (P values above 0.05). The protein expression of Slingshot-2 of cells was decreased at first and then gradually increased from hypoxia hour 1 to 24. The protein expression of Slingshot-2 of cells exposed to hypoxia for 24 h (1.54 ± 0.57) was significantly higher than that of cells exposed to hypoxia for 0 h (1.00, P<0.05). (3) Compared with those of cells exposed to hypoxia for 0 h, the content of F-actin of cells exposed to hypoxia for 1, 6, 12, and 24 h was significantly decreased, whereas the content of G-actin of cells exposed to hypoxia for 6-24 h was significantly increased, P<0.05 or P<0.01; the content of F-actin and G-actin of cells exposed to hypoxia for the other time points was not obviously changed (P values above 0.05).</p><p><b>CONCLUSIONS</b>Hypoxia may cause cofilin activation after dephosphorylation and the depolymerization of F-actin by inducing Slingshot-2 protein expression, which in turn affects the tight junction of human intestinal epithelial cells, thus leading to deterioration of barrier function of these cells.</p>