Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 3.556
Filtrar
1.
Life Sci ; 241: 117164, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31838135

RESUMO

AIMS: This study was to assess whether andrographolide derivative (AL-1) could restore mucosal homeostasis and regulate tight junctions through MLCK-dependent pathway in DSS-induced colitis mice. MAIN METHODS: Colitis mice model was induced by daily administration of 2.5% DSS for seven days. The therapeutic effect was determined by evaluating the histopathological changes and the pro-inflammatory cytokine level. In addition, the effects of AL-1 on tight junctions were examined by immunohistochemistry and Western blot. The expressions of factors in MLCK-dependent pathway were evaluated by immunofluorescence and Western blot. KEY FINDINGS: AL-1 protected the intestinal barrier function in DSS-induced colitis mice. These protective effects were achieved by maintaining the normal mucus secretion and preserving tight junctions via suppression of the MLCK-dependent pathway. SIGNIFICANCE: AL-1 could prevent the increase in the DSS-induced intestinal permeability. These data indicated that AL-1 could be a promising agent for UC treatment.


Assuntos
Anti-Inflamatórios/farmacologia , Permeabilidade da Membrana Celular/fisiologia , Colite/tratamento farmacológico , Sulfato de Dextrana/toxicidade , Diterpenos/farmacologia , Mucosa Intestinal/efeitos dos fármacos , Junções Íntimas/efeitos dos fármacos , Animais , Anti-Inflamatórios/química , Permeabilidade da Membrana Celular/efeitos dos fármacos , Colite/induzido quimicamente , Colite/metabolismo , Colite/patologia , Diterpenos/química , Mucosa Intestinal/metabolismo , Mucosa Intestinal/patologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Quinase de Cadeia Leve de Miosina/metabolismo , Fosforilação , Transdução de Sinais , Junções Íntimas/metabolismo , Junções Íntimas/patologia
2.
Toxicol Lett ; 321: 73-82, 2020 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-31862507

RESUMO

An enterogenic infection occurs when intestinal mucosal disruption is followed by the invasion of intestinal bacteria into the blood and distant organs, which can result in severe diseases or even death. Our previous study using Rhesus monkeys as an in vivo model revealed that methamphetamine (MA) induced intestinal mucosal barrier damage, which poses a high risk of enterogenic infection. However, how methamphetamine causes intestinal mucosal barrier damage remains largely unknown. In this study, we employed an in vitro model, and found that MA treatment could inhibit the expression of miR-181c, which directly targets and regulates TNF-α, and ultimately induces apoptosis and damages the intestinal barrier. Moreover, we measured TNF-α serum levels as well as the intestinal mucosal barrier damage indicators (diamine oxidase, d-lactic acid, and exotoxin) and found that their levels were significantly higher in MA-dependents than in healthy controls (P < 0.001). To the best of our knowledge, this is the first report evidencing that miR-181c is involved in MA-induced intestinal barrier injury via TNF-α regulation, which introduces novel potential therapeutic targets for MA-dependent intestinal diseases.


Assuntos
Transtornos Relacionados ao Uso de Anfetaminas/metabolismo , Estimulantes do Sistema Nervoso Central/efeitos adversos , Células Epiteliais/efeitos dos fármacos , Mucosa Intestinal/efeitos dos fármacos , Metanfetamina/efeitos adversos , MicroRNAs/metabolismo , Junções Íntimas/efeitos dos fármacos , Fator de Necrose Tumoral alfa/metabolismo , Adolescente , Adulto , Transtornos Relacionados ao Uso de Anfetaminas/sangue , Transtornos Relacionados ao Uso de Anfetaminas/genética , Transtornos Relacionados ao Uso de Anfetaminas/patologia , Animais , Apoptose/efeitos dos fármacos , Translocação Bacteriana/efeitos dos fármacos , Biomarcadores/sangue , Estudos de Casos e Controles , Linhagem Celular , Impedância Elétrica , Células Epiteliais/metabolismo , Células Epiteliais/patologia , Feminino , Microbioma Gastrointestinal , Humanos , Mucosa Intestinal/metabolismo , Mucosa Intestinal/patologia , Masculino , MicroRNAs/genética , Pessoa de Meia-Idade , Permeabilidade , Ratos , Transdução de Sinais , Junções Íntimas/metabolismo , Junções Íntimas/patologia , Fator de Necrose Tumoral alfa/sangue , Fator de Necrose Tumoral alfa/genética , Adulto Jovem
3.
Zhonghua Nei Ke Za Zhi ; 59(1): 40-46, 2020 Jan 01.
Artigo em Chinês | MEDLINE | ID: mdl-31887835

RESUMO

Objective: To investigate the association between adherens junction proteins E-cadherin and ß-catenin and tight junction protein claudin-2 and clinical symptoms in patients with diarrhea predominant irritable bowel syndrome (IBS-D). Methods: Cecal biopsy tissues were collected from IBS-D patients (n=26) according to Rome Ⅲ criterion and healthy controls (n=26). The duration of symptoms, abdominal pain score and mean weekly bowel movements were recorded. Colorectal dilatation combined with restraint stress were applied to establish visceral hypersensitivity rat model. Abdominal contraction reflex (AWR) was applied to assess the visceral sensitivity in rats. The stool frequency within 1 hour was recorded after establishing the rat model. The expression of E-cadherin、ß-catenin and claudin-2 were assessed by Western blot and immunofluorescence microscopy. Intercellular ultrastructure was observed by transmission electron microscopy. Results: Compared with the healthy controls, the protein expression of E-cadherin and ß-catenin in cecal epithelium in IBS-D patients were significantly lower (P=0.015 and P=0.005, respectively), while claudin-2 was significantly higher (P=0.000). Reduced E-cadherin and ß-catenin expression was associated high abdominal pain score (r=-0.463, P=0.017 and r=-0.407, P=0.039). The lower expression of ß-catenin was associated with longer duration of symptoms (r=-0.458, P=0.019). The protein expression of E-cadherin and ß-catenin in the cecal epithelium of the visceral hypersensitivity rats were significantly lower (P=0.004 and P=0.003, respectively), while claudin-2 was significantly higher (P=0.008). Reduced E-cadherin and ß-catenin expression was associated high visceral sensitivity in IBS-D rats (r=-0.639, P=0.047 and r=-0.888, P=0.001). Conclusions: Intercellular ultrastructure alterations well as cecal ß-catenin and E-cadherin protein expression decrease and are associated with high abdominal pain score in IBS-D patients and hypersensitivity rats. ß-catenin is further associated with prolonged duration of symptoms in IBS-D patients. The expression of E-cadherin and ß-catenin may play a vital role in visceral sensitivity and intestinal barrier dysfunction in IBS-D.


Assuntos
Junções Aderentes/metabolismo , Caderinas/metabolismo , Síndrome do Intestino Irritável/metabolismo , Junções Íntimas/metabolismo , Dor Abdominal/metabolismo , Dor Abdominal/fisiopatologia , Animais , Biópsia , Estudos de Casos e Controles , Ceco/metabolismo , Claudina-2 , Diarreia/metabolismo , Humanos , Mucosa Intestinal/metabolismo , Mucosa Intestinal/patologia , Síndrome do Intestino Irritável/patologia , Ratos , beta Catenina
4.
Life Sci ; 238: 116971, 2019 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-31634462

RESUMO

AIM: High-fat diet (HFD) intake has been associated with changes in intestinal microbiota composition, increased intestinal permeability, and onset of type 2 diabetes mellitus (T2DM). The aim of this work was twofold: 1) to investigate the structural and functional alterations of the tight junction (TJ)-mediated intestinal epithelial barrier of ileum and colon, that concentrate most of the microbiota, after exposure to a HFD for 15, 30 and 60 days, and 2) to assess the effect of in vitro exposure to free fatty acids (FFAs), one of the components of HFD, on paracellular barrier of colon-derived Caco-2 cells. METHODS/KEY FINDINGS: HFD exposure induced progressive metabolic changes in male mice that culminated in prediabetes after 60d. Morphological analysis of ileum and colon mucosa showed no signs of epithelial rupture or local inflammation but changes in the junctional content/distribution and/or cellular content of TJ-associated proteins (claudins-1, -2, -3, and occludin) in intestinal epithelia were seen mainly after a prediabetes state has been established. This impairment in TJ structure was not associated with significant changes in intestinal permeability to FITC-dextran. Exposure of Caco-2 monolayers to palmitic or linoleic acids seems to induce a reinforcement of TJ structure while treatment with oleic acid had a more diverse effect on TJ protein distribution. SIGNIFICANCE: TJ structure in distal intestinal epithelia can be specifically impaired by HFD intake at early stage of T2DM, but not by FFAs in vitro. Since the TJ change in ileum/colon was marginal, probably it does not contribute to the disease onset.


Assuntos
Diabetes Mellitus Experimental/patologia , Diabetes Mellitus Tipo 2/patologia , Dieta Hiperlipídica/efeitos adversos , Mucosa Intestinal/patologia , Estado Pré-Diabético/patologia , Junções Íntimas/patologia , Animais , Células CACO-2 , Diabetes Mellitus Experimental/etiologia , Diabetes Mellitus Experimental/metabolismo , Diabetes Mellitus Tipo 2/etiologia , Diabetes Mellitus Tipo 2/metabolismo , Humanos , Mucosa Intestinal/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Ocludina , Estado Pré-Diabético/etiologia , Estado Pré-Diabético/metabolismo , Proteínas de Junções Íntimas/metabolismo , Junções Íntimas/metabolismo , Fatores de Tempo
5.
Pharm Res ; 36(12): 172, 2019 Oct 28.
Artigo em Inglês | MEDLINE | ID: mdl-31659456

RESUMO

PURPOSE: Caco-2 monolayers are the most common model of the intestinal epithelium and are critical to the development of oral drug delivery strategies and gastrointestinal disease treatments. However, current monolayer systems are cost- and/or time-intensive, hampering progress. This study evaluates two separate methods to reduce resource input: FB Essence as a fetal bovine serum (FBS) alternative and a new, 3-day Caco-2 system deemed "thrifty, rapid intestinal monolayers" (TRIM). METHODS: Caco-2 cells were cultured with FB Essence and compared to cells in 10% FBS for proliferation and monolayer formation. TRIM were compared to commonly-used 21-day and Corning® HTS monolayer systems, as well as mouse intestines, for permeability behavior, epithelial gene expression, and tight junction arrangement. RESULTS: No amount of FB Essence maintained Caco-2 cells beyond 10 passages. In contrast, TRIM compared favorably in permeability and gene expression to intestinal tissues. Furthermore, TRIM cost $109 and required 1.3 h of time per 24-well plate, compared to $164 and 3.7 h for 21-day monolayers, and $340 plus 1.0 h for the HTS system. CONCLUSIONS: TRIM offer a new approach to generating Caco-2 monolayers that resemble the intestinal epithelium. They are anticipated to accelerate the pace of in vitro intestinal experiments while easing financial burden.


Assuntos
Mucosa Intestinal/metabolismo , Administração Oral , Animais , Células CACO-2 , Proliferação de Células , Células Cultivadas , Colágeno/química , Dextranos/metabolismo , Liberação Controlada de Fármacos , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Permeabilidade , Propriedades de Superfície , Junções Íntimas/metabolismo
6.
J Biochem Mol Toxicol ; 33(11): e22397, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31557363

RESUMO

Fumonisins (Fums) are mycotoxins widely distributed in crops and feed, and ingestion of Fums-contaminated crops is harmful to animal health. The purpose of this study is to explore the effect of Fum B1 (FB1 ) on barrier functions of porcine intestinal epithelial cells, IPEC-J2, to clarify the intestinal toxicity of Fums in pigs. The results showed that the persistent treatment of FB1 significantly decreased the viability of IPEC-J2. Moreover, the expressions of Claudin 1, Occludin, Zonula Occluden-1 (ZO-1) on the messenger RNA (mRNA), and protein levels and MUC1 on the mRNA level were significantly inhibited after FB1 treatment, while the mRNA relative expression level of MUC2 was clearly increased. FB1 also enhanced the monolayer cell permeability of IPEC-J2. Importantly, FB1 promoted the expression of phosphorylated extracellular regulated protein kinase (p-ERK1/2 ). These data suggest that long-term treatment of FB1 can suppress IPEC-J2 proliferation, damage tight junctions of IPEC-J2, and regulate expression of mucins to induce the damage of barrier functions of porcine intestinal epithelial cells, which may be associated with the ERK1/2 phosphorylation pathway.


Assuntos
Células Epiteliais/metabolismo , Fumonisinas/farmacologia , Mucosa Intestinal/citologia , Micotoxinas/farmacologia , Permeabilidade/efeitos dos fármacos , Junções Íntimas/efeitos dos fármacos , Animais , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Fusarium/metabolismo , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Mucina-1/genética , Mucina-1/metabolismo , Mucina-2/genética , Mucina-2/metabolismo , Fosforilação/efeitos dos fármacos , RNA Mensageiro/genética , Reação em Cadeia da Polimerase em Tempo Real , Transdução de Sinais/efeitos dos fármacos , Suínos , Proteínas de Junções Íntimas/genética , Proteínas de Junções Íntimas/metabolismo , Junções Íntimas/metabolismo
7.
Invest Ophthalmol Vis Sci ; 60(12): 3842-3853, 2019 09 03.
Artigo em Inglês | MEDLINE | ID: mdl-31529081

RESUMO

Purpose: Outer blood retinal barrier breakdown is a neglected feature of diabetic retinopathy (DR). We demonstrated that the agonism of the δ opioid receptor (DOR) by epicatechin preserves the tight junction proteins in ARPE-19 cells under diabetic conditions. Presently, we aimed to evaluate the possible role of the DOR on the maintenance of tight junction of RPE layer and on the early markers of experimental DR. Methods: DR markers and external retinal tight junction proteins were evaluated in CL57B diabetic mice submitted to intravitreous injection of short hairpin RNA (shRNA)-DOR (108 transducing units [TU]/mL) treated or not with DOR agonist (0.05 g/animal/d of epicatechin in drinking water) for 16 weeks. The presence of DOR in human retina from postmortem eyes from diabetic and nondiabetic donors were also performed. Results: DOR is present in RPE layer and in neuro retina. The treatment with DOR agonist prevented the upregulation of the early markers of retinopathy (glial fibrillary acidic protein, VEGF) and the downregulation of pigment epithelium-derived factor, occludin, claudin-1, and zonula occludens-1 tight junction expressions. The silencing of DOR in retina of diabetic mice partially abolished the protective effects of epicatechin. In human retina specimens, DOR is present throughout the retina, similarly in nondiabetic and diabetic donors. Conclusions: This set of experiments strongly indicates that the DOR agonism preserves RPE tight junctions and reduces the early markers of retinopathy in model of diabetes. These novel findings designate DOR as a potential therapeutic tool to treat DR with preservation of the RPE tight junction proteins.


Assuntos
Catequina/farmacologia , Diabetes Mellitus Experimental/prevenção & controle , Retinopatia Diabética/prevenção & controle , Receptores Opioides delta/agonistas , Epitélio Pigmentado da Retina/metabolismo , Junções Íntimas/metabolismo , Idoso , Animais , Glicemia/metabolismo , Western Blotting , Claudina-1/metabolismo , Diabetes Mellitus Experimental/metabolismo , Retinopatia Diabética/metabolismo , Retinopatia Diabética/patologia , Impedância Elétrica , Proteínas do Olho/metabolismo , Feminino , Técnica Indireta de Fluorescência para Anticorpo , Proteína Glial Fibrilar Ácida/metabolismo , Humanos , Imuno-Histoquímica , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Pessoa de Meia-Idade , Fatores de Crescimento Neural/metabolismo , Ocludina/metabolismo , RNA Interferente Pequeno , Reação em Cadeia da Polimerase em Tempo Real , Receptores Opioides delta/metabolismo , Serpinas/metabolismo , Fator A de Crescimento do Endotélio Vascular/metabolismo , Proteína da Zônula de Oclusão-1/metabolismo
8.
Int J Mol Sci ; 20(18)2019 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-31500238

RESUMO

The inner medullary collecting duct (IMCD) is subject to severe changes in ambient osmolality and must either allow water transport or be able to seal the lumen against a very high osmotic pressure. We postulate that the tight junction protein claudin-19 is expressed in IMCD and that it takes part in epithelial adaptation to changing osmolality at different functional states. Presence of claudin-19 in rat IMCD was investigated by Western blotting and immunofluorescence. Primary cell culture of rat IMCD cells on permeable filter supports was performed under different osmotic culture conditions and after stimulation by antidiuretic hormone (AVP). Electrogenic transepithelial transport properties were measured in Ussing chambers. IMCD cells cultivated at 300 mosm/kg showed high transepithelial resistance, a cation selective paracellular pathway and claudin-19 was mainly located in the tight junction. Treatment by AVP increased cation selectivity but did not alter transepithelial resistance or claudin-19 subcellular localization. In contrast, IMCD cells cultivated at 900 mosm/kg had low transepithelial resistance, anion selectivity, and claudin-19 was relocated from the tight junctions to intracellular vesicles. The data shows osmolality-dependent transformation of IMCD epithelium from tight and sodium-transporting to leaky, with claudin-19 expression in the tight junction associated to tightness and cation selectivity under low osmolality.


Assuntos
Claudinas/metabolismo , Túbulos Renais Coletores/citologia , Junções Íntimas/metabolismo , Vasopressinas/farmacologia , Animais , Proliferação de Células/efeitos dos fármacos , Células Cultivadas , Regulação da Expressão Gênica/efeitos dos fármacos , Túbulos Renais Coletores/efeitos dos fármacos , Túbulos Renais Coletores/metabolismo , Camundongos , Concentração Osmolar , Ratos , Migração Transendotelial e Transepitelial
9.
Int J Mol Sci ; 20(18)2019 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-31500278

RESUMO

Extracellular vesicles (EVs) are nanometer-sized membranous vesicles used for primitive cell-to-cell communication. We previously reported that colon cancer-derived EVs contain abundant miR-92a-3p and have a pro-angiogenic function. We previously identified Dickkopf-3 (Dkk-3) as a direct target of miR-92a-3p; however, the pro-angiogenic function of miR-92a-3p cannot only be attributed to downregulation of Dkk-3. Therefore, the complete molecular mechanism by which miR-92a-3p exerts pro-angiogenic effects is still unclear. Here, we comprehensively analyzed the gene sets affected by ectopic expression of miR-92a-3p in endothelial cells to elucidate processes underlying EV-induced angiogenesis. We found that the ectopic expression of miR-92a-3p upregulated cell cycle- and mitosis-related gene expression and downregulated adhesion-related gene expression in endothelial cells. We also identified a novel target gene of miR-92a-3p, claudin-11. Claudin-11 belongs to the claudin gene family, which encodes essential components expressed at tight junctions (TJs). Disruption of TJs with a concomitant loss of claudin expression is a significant event in the process of epithelial-to-mesenchymal transition. Our findings have unveiled a new EV-mediated mechanism for tumor angiogenesis through the induction of partial endothelial-to-mesenchymal transition in endothelial cells.


Assuntos
Claudinas/genética , Neoplasias do Colo/irrigação sanguínea , Vesículas Extracelulares/genética , MicroRNAs/genética , Neovascularização Patológica/genética , Linhagem Celular Tumoral , Claudinas/metabolismo , Neoplasias do Colo/genética , Neoplasias do Colo/metabolismo , Células Endoteliais/química , Células Endoteliais/citologia , Transição Epitelial-Mesenquimal , Regulação Neoplásica da Expressão Gênica , Redes Reguladoras de Genes , Células Endoteliais da Veia Umbilical Humana , Humanos , Neovascularização Patológica/metabolismo , Mapas de Interação de Proteínas , Junções Íntimas/genética , Junções Íntimas/metabolismo
10.
Toxicol Lett ; 316: 109-118, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31472180

RESUMO

Lithocholic acid (LCA) is both a secondary bile acid and a vitamin D receptor (VDR) ligand. The VDR is activated by 1,25-dihydroxy vitamin D3 and plays an important role in maintaining integrity of the intestinal mucosal barrier. LCA can also substitute for vitamin D to carry out the in vivo functions of vitamin D. However, it is unclear whether activation of the VDR by LCA affects mucosal barrier function. In the present study, we researched the protective effect of LCA on tumor necrosis factor-alpha (TNF-α)-induced intestinal epithelial barrier dysfunction in Caco-2 cells of the human epithelial intestinal adenocarcinoma cell line. Caco-2 cell monolayers were pretreated with LCA and then exposed to 100 ng/mL TNF-α. The results showed that LCA alleviated the decrease in transepithelial electrical resistance and the increase in FITC-Dextran flux induced by TNF-α. LCA ameliorated the TNF-α-induced decrease in protein expression and distribution of ZO-1, E-cadherin, Occludin, and Claudin-1, which are tight junction markers. Additionally, the LCA treatment effectively counteracted TNF-α-mediated downregulation of silent information regulator 1 (SIRT1), nuclear factor erythroid2-related factor 2 (Nrf2), and heme oxygenase-1, which are related to oxidative stress. Increases in NF-κB p-p65 and p-IκB-α induced by TNF-α were significantly inhibited by LCA. Considering all these, the present study indicates that LCA has a significant protective effect on TNF-α-induced injury of intestinal barrier function through the VDR and suggests that suppressing NF-κB signaling and activating the SIRT1/Nrf2 pathway might be one of the mechanisms underlying the protective effect of LCA.


Assuntos
Células Epiteliais/efeitos dos fármacos , Absorção Intestinal/efeitos dos fármacos , Mucosa Intestinal/efeitos dos fármacos , Ácido Litocólico/farmacologia , Fator 2 Relacionado a NF-E2/metabolismo , NF-kappa B/metabolismo , Receptores de Calcitriol/agonistas , Sirtuína 1/metabolismo , Fator de Necrose Tumoral alfa/toxicidade , Células CACO-2 , Citoproteção , Impedância Elétrica , Células Epiteliais/metabolismo , Células Epiteliais/patologia , Humanos , Mucosa Intestinal/metabolismo , Mucosa Intestinal/patologia , Permeabilidade , Receptores de Calcitriol/genética , Receptores de Calcitriol/metabolismo , Transdução de Sinais/efeitos dos fármacos , Proteínas de Junções Íntimas/metabolismo , Junções Íntimas/efeitos dos fármacos , Junções Íntimas/metabolismo , Junções Íntimas/patologia
11.
Int J Mol Sci ; 20(16)2019 Aug 08.
Artigo em Inglês | MEDLINE | ID: mdl-31398894

RESUMO

Claudin-1 (CLDN1) is expressed in the tight junction (TJ) of the skin granular layer and acts as a physiological barrier for the paracellular transport of ions and nonionic molecules. Ultraviolet (UV) and oxidative stress may disrupt the TJ barrier, but the mechanism of and protective agents against this effect have not been clarified. We found that UVB and hydrogen peroxide (H2O2) caused the internalization of CLDN1 and increased the paracellular permeability of lucifer yellow, a fluorescent marker, in human keratinocyte-derived HaCaT cells. Therefore, the mechanism of mislocalization of CLDN1 and the protective effect of an ethanol extract of Brazilian green propolis (EBGP) were investigated. The UVB- and H2O2-induced decreases in CLDN1 localization were rescued by EBGP. H2O2 decreased the phosphorylation level of CLDN1, which was also rescued by EBGP. Wild-type CLDN1 was distributed in the cytosol after treatment with H2O2, whereas T191E, its H2O2-insensitive phosphorylation-mimicking mutant, was localized at the TJ. Both protein kinase C activator and protein phosphatase 2A inhibitor rescued the H2O2-induced decrease in CLDN1 localization. The tight junctional localization of CLDN1 and paracellular permeability showed a negative correlation. Our results indicate that UVB and H2O2 could induce the elevation of paracellular permeability mediated by the dephosphorylation and mislocalization of CLDN1 in HaCaT cells, which was rescued by EBGP. EBGP and its components may be useful in preventing the destruction of the TJ barrier through UV and oxidative stress.


Assuntos
Claudina-1/metabolismo , Queratinócitos/efeitos dos fármacos , Queratinócitos/metabolismo , Estresse Oxidativo , Própole/farmacologia , Permeabilidade da Membrana Celular/efeitos dos fármacos , Claudina-1/genética , Endocitose/efeitos dos fármacos , Expressão Gênica , Humanos , Peróxido de Hidrogênio/metabolismo , Mutação , Fosforilação , Transporte Proteico , Espécies Reativas de Oxigênio/metabolismo , Junções Íntimas/metabolismo
12.
Life Sci Alliance ; 2(4)2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31399484

RESUMO

The paracellular barrier function of tight junctions (TJs) in epithelial cell sheets is robustly maintained against mechanical fluctuations, by molecular mechanisms that are poorly understood. Vinculin is an adaptor of a mechanosensory complex at the adherens junction. Here, we generated vinculin KO Eph4 epithelial cells and analyzed their confluent cell-sheet properties. We found that vinculin is dispensable for the basic TJ structural integrity and the paracellular barrier function for larger solutes. However, vinculin is indispensable for the paracellular barrier function for ions. In addition, TJs stochastically showed dynamically distorted patterns in vinculin KO cell sheets. These KO phenotypes were rescued by transfecting full-length vinculin and by relaxing the actomyosin tension with blebbistatin, a myosin II ATPase activity inhibitor. Our findings indicate that vinculin resists mechanical fluctuations to maintain the TJ paracellular barrier function for ions in epithelial cell sheets.


Assuntos
Células Epiteliais/citologia , Vinculina/genética , Vinculina/metabolismo , Actomiosina/metabolismo , Linhagem Celular , Células Epiteliais/metabolismo , Técnicas de Inativação de Genes , Células HEK293 , Compostos Heterocíclicos de 4 ou mais Anéis/farmacologia , Humanos , Íons/metabolismo , Processos Estocásticos , Junções Íntimas/efeitos dos fármacos , Junções Íntimas/metabolismo
13.
Int J Mol Sci ; 20(16)2019 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-31430850

RESUMO

Phosphatidylcholine (PC) translocation into mucus of the intestine was shown to occur via a paracellular transport across the apical/lateral tight junction (TJ) barrier. In case this could also be operative in biliary epithelial cells, this may have implication for the pathogenesis of primary sclerosing cholangitis (PSC). We here evaluated the transport of PC across polarized cholangiocytes. Therefore, the biliary tumor cell line Mz-ChA-1 was grown to confluency. In transwell culture systems the translocation of PC to the apical compartment was analyzed. After 21 days in culture, polarized Mz-ChA-1 cells revealed a predominant apical translocation of choline containing phospholipids including PC with minimal intracellular accumulation. Transport was suppressed by TJ destruction employing chemical inhibitors and pretreatment with siRNA to TJ forming proteins as well as the apical transmembrane mucin 3 as PC acceptor. Apical translocation was dependent on a negative apical electrical potential created by the cystic fibrosis transmembrane conductance regulator (CFTR) and the anion exchange protein 2 (AE2). It was stimulated by apical application of secretory mucins. The results indicated the existence of a paracellular PC passage across apical/lateral TJ of the polarized biliary epithelial tumor cell line Mz-ChA-1. This has implication for the generation of a protective mucus barrier in the biliary tree.


Assuntos
Sistema Biliar/metabolismo , Células Epiteliais/metabolismo , Fosfatidilcolinas/metabolismo , Sistema Biliar/citologia , Neoplasias do Sistema Biliar/metabolismo , Linhagem Celular Tumoral , Polaridade Celular , Células Epiteliais/citologia , Humanos , Junções Íntimas/metabolismo , Transcitose
14.
Int J Mol Sci ; 20(16)2019 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-31430854

RESUMO

Blood-brain barrier (BBB) disruption is a critical event after ischemic stroke, which results in edema formation and hemorrhagic transformation of infarcted tissue. BBB dysfunction following stroke is partly mediated by proinflammatory agents. We recently have shown that high frequency stimulation of the mesencephalic locomotor region (MLR-HFS) exerts an antiapoptotic and anti-inflammatory effect in the border zone of cerebral photothrombotic stroke in rats. Whether MLR-HFS also has an impact on BBB dysfunction in the early stage of stroke is unknown. In this study, rats were subjected to photothrombotic stroke of the sensorimotor cortex and implantation of a stimulating microelectrode into the ipsilesional MLR. Thereafter, either HFS or sham stimulation of the MLR was applied for 24 h. After scarifying the rats, BBB disruption was assessed by determining albumin extravasation and tight junction integrity (claudin 3, claudin 5, and occludin) using Western blot analyses and immunohistochemistry. In addition, by applying zymography, expression of pro-metalloproteinase-9 (pro-MMP-9) was analyzed. No differences were found regarding infarct size and BBB dysfunction between stimulated and unstimulated animals 24 h after induction of stroke. Our results indicate that MLR-HFS neither improves nor worsens the damaged BBB after stroke. Attenuating cytokines/chemokines in the perilesional area, as mediated by MLR-HFS, tend to play a less significant role in preventing the BBB integrity.


Assuntos
Barreira Hematoencefálica/fisiopatologia , Terapia por Estimulação Elétrica , Mesencéfalo/fisiopatologia , Acidente Vascular Cerebral/terapia , Animais , Masculino , Ratos , Ratos Wistar , Acidente Vascular Cerebral/fisiopatologia , Junções Íntimas/metabolismo
15.
Eur J Pharm Biopharm ; 143: 98-105, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31425857

RESUMO

Oral delivery of peptides is challenging due to their low uptake through the small intestinal epithelium. Tight junctions, connecting the enterocytes, impede permeability, often necessitating the use of permeation enhancers in the formulation. Loading of peptide and permeation enhancer into micro-scale devices, such as microcontainers, can potentially confine the effective absorptive area through unidirectional release and thereby enhance absorption. This concept is investigated by in vitro permeation studies of insulin across Caco-2 cell and Caco-2/HT29-MTX-E12 co-culture monolayers mimicking the intestinal absorption barrier. The importance of proximity between the microcontainers and the barrier is assessed, by keeping the amounts of insulin and sodium caprate fixed throughout all experiments, while collectively orienting the unidirectional release towards the cell monolayers. Increasing the distance is observed to have a negative effect on insulin permeation matching a one-phase exponential decay function, while no difference in insulin transport is observed between Caco-2 and co-culture monolayers. Although there are no signs of cytotoxicity caused by the microcontainer material, reversible cell deterioration, as a consequence of high local concentrations of sodium caprate, becomes evident upon qualitative assessment of the cell monolayers. These results both suggest a potential of increasing oral bioavailability of peptides by the use of microcontainers, while simultaneously visualising the ability of regaining monolayer integrity upon local permeation enhancer induced toxicity.


Assuntos
Insulina/administração & dosagem , Insulina/química , Permeabilidade/efeitos dos fármacos , Administração Oral , Disponibilidade Biológica , Transporte Biológico/efeitos dos fármacos , Células CACO-2 , Linhagem Celular Tumoral , Técnicas de Cocultura/métodos , Humanos , Absorção Intestinal/efeitos dos fármacos , Mucosa Intestinal/metabolismo , Peptídeos/administração & dosagem , Peptídeos/química , Junções Íntimas/metabolismo
16.
Int J Mol Sci ; 20(17)2019 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-31438472

RESUMO

Atopic dermatitis (AD) is the most common chronic and relapsing inflammatory skin disease. AD is typically characterized by skewed T helper (Th) 2 inflammation, yet other inflammatory profiles (Th1, Th17, Th22) have been observed in human patients. How cytokines from these different Th subsets impact barrier function in this disease is not well understood. As such, we investigated the impact of the canonical Th17 cytokine, IL-17A, on barrier function and protein composition in primary human keratinocytes and human skin explants. These studies demonstrated that IL-17A enhanced tight junction formation and function in both systems, with a dependence on STAT3 signaling. Importantly, the Th2 cytokine, IL-4 inhibited the barrier-enhancing effect of IL-17A treatment. These observations propose that IL-17A helps to restore skin barrier function, but this action is antagonized by Th2 cytokines. This suggests that restoration of IL-17/IL-4 ratio in the skin of AD patients may improve barrier function and in so doing improve disease severity.


Assuntos
Epiderme/efeitos dos fármacos , Epiderme/metabolismo , Interleucina-17/farmacologia , Interleucina-4/farmacologia , Junções Íntimas/efeitos dos fármacos , Junções Íntimas/metabolismo , Células Cultivadas , Claudina-4/metabolismo , Dermatite Atópica/metabolismo , Humanos , Técnicas In Vitro , Queratinócitos/efeitos dos fármacos , Queratinócitos/metabolismo , Fator de Transcrição STAT3/metabolismo , Pele/efeitos dos fármacos , Pele/metabolismo
17.
Int J Mol Sci ; 20(17)2019 Aug 24.
Artigo em Inglês | MEDLINE | ID: mdl-31450555

RESUMO

ZO-2 is a cytoplasmic protein of tight junctions (TJs). Here, we describe ZO-2 involvement in the formation of the apical junctional complex during early development and in TJ biogenesis in epithelial cultured cells. ZO-2 acts as a scaffold for the polymerization of claudins at TJs and plays a unique role in the blood-testis barrier, as well as at TJs of the human liver and the inner ear. ZO-2 movement between the cytoplasm and nucleus is regulated by nuclear localization and exportation signals and post-translation modifications, while ZO-2 arrival at the cell border is triggered by activation of calcium sensing receptors and corresponding downstream signaling. Depending on its location, ZO-2 associates with junctional proteins and the actomyosin cytoskeleton or a variety of nuclear proteins, playing a role as a transcriptional repressor that leads to inhibition of cell proliferation and transformation. ZO-2 regulates cell architecture through modulation of Rho proteins and its absence induces hypertrophy due to inactivation of the Hippo pathway and activation of mTOR and S6K. The interaction of ZO-2 with viral oncoproteins and kinases and its silencing in diverse carcinomas reinforce the view of ZO-2 as a tumor regulator protein.


Assuntos
Regulação da Expressão Gênica , Transdução de Sinais , Proteína da Zônula de Oclusão-2/genética , Proteína da Zônula de Oclusão-2/metabolismo , Actomiosina/metabolismo , Animais , Apoptose/genética , Proliferação de Células , Forma Celular , Tamanho Celular , Desenvolvimento Embrionário/genética , Humanos , Proteínas Nucleares/metabolismo , Especificidade de Órgãos/genética , Ligação Proteica , Transporte Proteico , Junções Íntimas/metabolismo , Transcrição Genética , Proteína da Zônula de Oclusão-2/química
18.
Int J Mol Sci ; 20(14)2019 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-31319610

RESUMO

Epithelia act as a barrier to the external environment. The extracellular environment constantly changes, and the epithelia are required to regulate their function in accordance with the changes in the environment. It has been reported that a difference of the environment between the apical and basal sides of epithelia such as osmolality and hydrostatic pressure affects various epithelial functions including transepithelial transport, cytoskeleton, and cell proliferation. In this paper, we review the regulation of epithelial functions by the gradients of osmolality and hydrostatic pressure. We also examine the significance of this regulation in pathological conditions especially focusing on the role of the hydrostatic pressure gradient in the pathogenesis of carcinomas. Furthermore, we discuss the mechanism by which epithelia sense the osmotic and hydrostatic pressure gradients and the possible role of the tight junction as a sensor of the extracellular environment to regulate epithelial functions.


Assuntos
Citoesqueleto/metabolismo , Células Epiteliais/metabolismo , Neoplasias/metabolismo , Junções Íntimas/metabolismo , Animais , Transporte Biológico , Células Epiteliais/patologia , Humanos , Pressão Hidrostática , Neoplasias/patologia , Concentração Osmolar
19.
Sci Total Environ ; 689: 662-678, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31279213

RESUMO

Microcystin-leucine-arginine (MC-LR), which produced by toxic cyanobacteria and widely present in eutrophic waters, has been shown to have potent acute hepatotoxicity. MC-LR has been revealed to inflict damage to brain, while the neurotoxicity of chronic exposure to MC-LR and mechanisms underlying it are still confusing. Here, the mice were exposed to MC-LR dissolved in drinking water at dose of 1, 7.5, 15, and 30 µg/L for consecutive 180 days. MC-LR accumulated in mouse brains and impaired the blood-brain barrier by inducing the expression of matrix metalloproteinase-8 (MMP-8), which was regulated by NF-κB, c-Fos and c-Jun. Furthermore, MC-LR exposure induced microglial and astrocyte activation and resultant neuroinflammatory response. This study highlights the risks to human health of the current microcystin exposure.


Assuntos
Barreira Hematoencefálica/efeitos dos fármacos , Inflamação/fisiopatologia , Microcistinas/toxicidade , Junções Íntimas/efeitos dos fármacos , Animais , Astrócitos/efeitos dos fármacos , Astrócitos/fisiologia , Expressão Gênica/efeitos dos fármacos , Inflamação/induzido quimicamente , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Microglia/efeitos dos fármacos , Microglia/fisiologia , Junções Íntimas/metabolismo
20.
Int J Mol Sci ; 20(13)2019 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-31262043

RESUMO

Interleukin-13 (IL-13) drives symptoms in asthma with high levels of T-helper type 2 cells (Th2-cells). Since tight junctions (TJ) constitute the epithelial diffusion barrier, we investigated the effect of IL-13 on TJ in human tracheal epithelial cells. We observed that IL-13 increases paracellular permeability, changes claudin expression pattern and induces intracellular aggregation of the TJ proteins zonlua occludens protein 1, as well as claudins. Furthermore, IL-13 treatment increases expression of ubiquitin conjugating E2 enzyme UBE2Z. Co-localization and proximity ligation assays further showed that ubiquitin and the proteasomal marker PSMA5 co-localize with TJ proteins in IL-13 treated cells, showing that TJ proteins are ubiquitinated following IL-13 exposure. UBE2Z upregulation occurs within the first day after IL-13 exposure. Proteasomal aggregation of ubiquitinated TJ proteins starts three days after IL-13 exposure and transepithelial electrical resistance (TEER) decrease follows the time course of TJ-protein aggregation. Inhibition of JAK/STAT signaling abolishes IL-13 induced effects. Our data suggest that that IL-13 induces ubiquitination and proteasomal aggregation of TJ proteins via JAK/STAT dependent expression of UBE2Z, resulting in opening of TJs. This may contribute to barrier disturbances in pulmonary epithelia and lung damage of patients with inflammatory lung diseases.


Assuntos
Células Epiteliais/metabolismo , Interleucina-13/farmacologia , Junções Íntimas/metabolismo , Traqueia/metabolismo , Células Cultivadas , Células Epiteliais/efeitos dos fármacos , Humanos , Janus Quinases/metabolismo , Complexo de Endopeptidases do Proteassoma/metabolismo , Fatores de Transcrição STAT/metabolismo , Junções Íntimas/efeitos dos fármacos , Traqueia/citologia , Enzimas de Conjugação de Ubiquitina/metabolismo , Ubiquitinação
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA