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Han Z, Ge L, Wen S, Sun J. Dysfunction of the intestinal physical barrier in the intestinal inflammation of tongue sole, Cynoglossus semilaevis, induced by Shewanella algae infection. FISH & SHELLFISH IMMUNOLOGY 2023:108900. [PMID: 37315911 DOI: 10.1016/j.fsi.2023.108900] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2023] [Revised: 06/10/2023] [Accepted: 06/12/2023] [Indexed: 06/16/2023]
Abstract
Bacterial intestinal inflammation occurs frequently in cultured fish. However, research on the dysfunction of the intestinal physical barrier in fish intestinal inflammation is scarce. In this study, intestinal inflammation in tongue sole Cynoglossus semilaevis was induced by Shewanella algae and the intestinal permeability was investigated. Gene expression patterns in inflammatory factors, tight junction molecules, and keratins 8 and 18 in the intestines were further explored. Histological examinations of the middle intestines showed that S. algae induced pathological lesions of intestinal inflammation and significantly increased the total number of mucous cells (p < 0.01). Ultrastructural observation in the middle intestines showed that intercellular spaces between epithelial cells were significantly wider in infected fish compared with the control (p < 0.01). The positive result of fluorescence in situ hybridization confirmed the presence of S. algae in the intestine. Enhanced Evans blue exudation and increased levels of serum d-lactate and intestinal fatty acid binding protein were suggestive of increased intestinal barrier permeability. The mRNA levels of four pro-inflammatory cytokines, namely IL-6, IL-8, IL-β, and TNF-α, were significantly increased after S. algae infection at most tested time points (p < 0.01 or p < 0.05), while there was an alternating increasing and decreasing trend in the gene expression patterns of IL-10, TGF-β, TLR-2, AP-1, and CASP-1. The mRNA expression of tight junction molecules (claudin-1, claudin-2, ZO-1, JAM-A, and MarvelD3) and keratins 8 and 18 in the intestines was significantly decreased at 6, 12, 24, 48, or 72 h post infection (p < 0.01 or p < 0.05). In conclusion, S. algae infection induced intestinal inflammation accompanied by increased intestinal permeability in tongue sole, and tight junction molecules and keratins were probably associated with the pathological process.
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Affiliation(s)
- Zhuoran Han
- Tianjin Key Lab of Aqua-ecology and Aquaculture, Fisheries College, Tianjin Agricultural University, Tianjin, 300384, China.
| | - Lunhua Ge
- Tianjin Key Lab of Aqua-ecology and Aquaculture, Fisheries College, Tianjin Agricultural University, Tianjin, 300384, China.
| | - Siyi Wen
- Tianjin Key Lab of Aqua-ecology and Aquaculture, Fisheries College, Tianjin Agricultural University, Tianjin, 300384, China.
| | - Jingfeng Sun
- Tianjin Key Lab of Aqua-ecology and Aquaculture, Fisheries College, Tianjin Agricultural University, Tianjin, 300384, China.
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2
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Yamamoto Y, Akanuma SI, Kon H, Endo H, Kubo Y, Hosoya KI. Newly-established in vitro inner BRB spheroids to elucidate retinal Ang2-linked substance transfer. J Control Release 2022; 351:8-21. [PMID: 36122894 DOI: 10.1016/j.jconrel.2022.09.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Revised: 09/09/2022] [Accepted: 09/11/2022] [Indexed: 10/31/2022]
Abstract
Conjugation of angiopep-2 (Ang2) with drugs/compounds is known to increase plasma membrane permeability across endothelial barriers. The inner blood-retinal barrier (BRB) regulates retinal drug distribution and is formed by retinal capillary endothelial cells, supported by Müller cells and retinal pericytes. To elucidate the potential of Ang2 conjugation in promoting retinal drug distribution after peripheral administration across the inner BRB, an in vivo administration study and in vitro transport experiments using newly developed multicellular inner BRB spheroids were performed. After intravenous administration of Ang2-linked green fluorescence protein (GFP-Ang2) in mice, GFP-derived signals were observed in the neural retina. In contrast, GFP-derived signals were not observed after intravenous GFP administration, suggesting the promotion of the retinal distribution of substances by Ang2 conjugation. To overcome the limitations of in vitro studies using cells cultured on dishes, inner BRB spheroids were established using conditionally immortalized rat retinal capillary endothelial cells, Müller cells, and retinal pericytes. Immunocytochemistry of marker molecules suggests that the central part of the spheroids is occupied by Müller cells, and encapsulated by retinal pericytes and capillary endothelial cells. Studies on the expression and functions of tight junctions suggest that tight junctions are formed on the surface of the inner BRB spheroids by retinal capillary endothelial cells. The functional expression of drug transporters, such as P-glycoprotein, was observed in the spheroids, implying that the inner side of the spheroids reflects the retinal side of the inner BRB. In the inner BRB spheroids, energy-dependent accumulation of GFP-Ang2 and Ang2-linked 5(6)-carboxyfluorescein (FAM-Ang2) was observed. Moreover, an endocytic inhibition study revealed that clathrin-dependent endocytosis/transcytosis was involved in the transcellular transport of Ang2-conjugated drugs/compounds across the inner BRB. Consequently, it is suggested that the Ang2 linkage is useful for promoting retinal drug distribution via clathrin-dependent transcytosis at the inner BRB.
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Affiliation(s)
- Yudai Yamamoto
- Department of Pharmaceutics, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Sugitani 2630, Toyama 930-0194, Japan
| | - Shin-Ichi Akanuma
- Department of Pharmaceutics, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Sugitani 2630, Toyama 930-0194, Japan.
| | - Hideki Kon
- Department of Pharmaceutics, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Sugitani 2630, Toyama 930-0194, Japan
| | - Hiroki Endo
- Department of Pharmaceutics, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Sugitani 2630, Toyama 930-0194, Japan
| | - Yoshiyuki Kubo
- Department of Pharmaceutics, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Sugitani 2630, Toyama 930-0194, Japan
| | - Ken-Ichi Hosoya
- Department of Pharmaceutics, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Sugitani 2630, Toyama 930-0194, Japan.
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3
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Jimenez IA, Stilin AP, Morohaku K, Hussein MH, Koganti PP, Selvaraj V. Mitochondrial translocator protein deficiency exacerbates pathology in acute experimental ulcerative colitis. Front Physiol 2022; 13:896951. [PMID: 36060674 PMCID: PMC9437295 DOI: 10.3389/fphys.2022.896951] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Accepted: 07/26/2022] [Indexed: 11/13/2022] Open
Abstract
In human patients and animal models of ulcerative colitis (UC), upregulation of the mitochondrial translocator protein (TSPO) in the colon is consistent with inflammation. Although the molecular function for TSPO remains unclear, it has been investigated as a therapeutic target for ameliorating UC pathology. In this study, we examined the susceptibility of Tspo gene-deleted (Tspo -/- ) mice to insults as provided by the dextran sodium sulfate (DSS)-induced acute UC model. Our results show that UC clinical signs and pathology were severely exacerbated in Tspo -/- mice compared to control Tspo fl/fl cohorts. Histopathology showed extensive inflammation and epithelial loss in Tspo -/- mice that caused an aggravated disease. Colonic gene expression in UC uncovered an etiology linked to precipitous loss of epithelial integrity and disproportionate mast cell activation assessed by tryptase levels in Tspo -/- colons. Evaluation of baseline homeostatic shifts in Tspo -/- colons revealed gene expression changes noted in elevated epithelial Cdx2, mast cell Cd36 and Mcp6, with general indicators of lower proliferation capacity and elevated mitochondrial fatty acid oxidation. These findings demonstrate that intact physiological TSPO function serves to limit inflammation in acute UC, and provide a systemic basis for investigating TSPO-targeting mechanistic therapeutics.
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Affiliation(s)
- Isabel A. Jimenez
- Department of Animal Science, College of Agriculture and Life Sciences, Cornell University, Ithaca, NY, United States,Department of Molecular and Comparative Pathobiology, The Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Allison P. Stilin
- Department of Animal Science, College of Agriculture and Life Sciences, Cornell University, Ithaca, NY, United States
| | - Kanako Morohaku
- Department of Animal Science, College of Agriculture and Life Sciences, Cornell University, Ithaca, NY, United States,School of Science and Technology, Institute of Agriculture, Shinshu University, Nagano, Japan
| | - Mahmoud H. Hussein
- Department of Animal Science, College of Agriculture and Life Sciences, Cornell University, Ithaca, NY, United States
| | - Prasanthi P. Koganti
- Department of Animal Science, College of Agriculture and Life Sciences, Cornell University, Ithaca, NY, United States
| | - Vimal Selvaraj
- Department of Animal Science, College of Agriculture and Life Sciences, Cornell University, Ithaca, NY, United States,*Correspondence: Vimal Selvaraj,
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Roles of Keratins in Intestine. Int J Mol Sci 2022; 23:ijms23148051. [PMID: 35887395 PMCID: PMC9317181 DOI: 10.3390/ijms23148051] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Revised: 07/19/2022] [Accepted: 07/19/2022] [Indexed: 12/02/2022] Open
Abstract
Keratins make up a major portion of epithelial intermediate filament proteins. The widely diverse keratins are found in both the small and large intestines. The human intestine mainly expresses keratins 8, 18, 19, and 20. Many of the common roles of keratins are for the integrity and stability of the epithelial cells. The keratins also protect the cells and tissue from stress and are biomarkers for some diseases in the organs. Although an increasing number of studies have been performed regarding keratins, the roles of keratin in the intestine have not yet been fully understood. This review focuses on discussing the roles of keratins in the intestine. Diverse studies utilizing mouse models and samples from patients with intestinal diseases in the search for the association of keratin in intestinal diseases have been summarized.
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Varani J, McClintock SD, Aslam MN. Cell-Matrix Interactions Contribute to Barrier Function in Human Colon Organoids. Front Med (Lausanne) 2022; 9:838975. [PMID: 35360746 PMCID: PMC8960989 DOI: 10.3389/fmed.2022.838975] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2021] [Accepted: 02/10/2022] [Indexed: 11/13/2022] Open
Abstract
The importance of cell-matrix adhesion to barrier control in the colon is unclear. The goals of the present study were to: (i) determine if disruption of colon epithelial cell interactions with the extracellular matrix alters permeability control measurement and (ii) determine if increasing the elaboration of protein components of cell-matrix adhesion complexes can mitigate the effects of cell-matrix disruption. Human colon organoids were interrogated for transepithelial electrical resistance (TEER) under control conditions and in the presence of Aquamin®, a multi-mineral product. A function-blocking antibody directed at the C-terminal region of the laminin α chain was used in parallel. The effects of Aquamin® on cell-matrix adhesion protein expression were determined in a proteomic screen and by Western blotting. Aquamin® increased the expression of multiple basement membrane, hemidesmosomal and focal adhesion proteins as well as keratin 8 and 18. TEER values were higher in the presence of Aquamin® than they were under control conditions. The blocking antibody reduced TEER values under both conditions but was most effective in the absence of Aquamin®, where expression of cell-matrix adhesion proteins was lower to begin with. These findings provide evidence that cell-matrix interactions contribute to barrier control in the colon.
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6
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Wu J, Niu J, Li M, Miao Y. Keratin 1 maintains the intestinal barrier in ulcerative colitis. Genes Genomics 2021; 43:1389-1402. [PMID: 34562265 DOI: 10.1007/s13258-021-01166-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2021] [Accepted: 09/14/2021] [Indexed: 12/20/2022]
Abstract
BACKGROUND The intestinal mechanical barrier plays a key role in the pathogenesis of ulcerative colitis (UC). Our previous study showed keratin 1 (KRT1) was downregulated in UC, but the mechanism by which KRT1 affects the intestinal barrier remains unknown. OBJECTIVES To explore the mechanism of KRT1 in the intestinal barrier in UC. METHODS Colonic tissues were collected from 20 UC patients before and after mucosal healing (MH) and 15 healthy controls. The expression of KRT1 was measured by PCR, western blotting and immunohistochemistry (IHC). A dextran sulfate sodium (DSS)-induced colitis model was established in krt1 transgenic (TG) mice, and the mice were treated with methylprednisolone (MP) to explore the role of KRT1 in the intestinal barrier. Inflammation was evaluated through the DAI score, colon, spleen and H&E. The expression of KRT1 and tight junction (TJ) proteins in mouse was analysed by the same methods. RESULTS The transcription and expression of KRT1 in UC was decreased and recovered after MH but did not reach the level of the healthy controls. Similar to the clinical results, the expression of krt1 was decreased in DSS-induced colitis and upregulated after MP. Moreover, the krt1 TG group exhibited less inflammation than wild-type (WT) group. The expression of Occludin and ZO-1 decreased after DSS induction, the decreases in Occludin and ZO-1 in the krt1 TG group were lower than WT group, which was significantly increased after MP, while the expression of Claudin-2 exhibited the opposite effect. CONCLUSIONS Keratin 1 maintains the intestinal barrier by upregulating TJ proteins in UC.
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Affiliation(s)
- Jing Wu
- Department of Gastroenterology, The First Affiliated Hospital of Kunming Medical University, No. 295 Xichang Road, Kunming, 650032, Yunnan, China
| | - Junkun Niu
- Department of Gastroenterology, The First Affiliated Hospital of Kunming Medical University, No. 295 Xichang Road, Kunming, 650032, Yunnan, China
| | - Maojuan Li
- Department of Gastroenterology, The First Affiliated Hospital of Kunming Medical University, No. 295 Xichang Road, Kunming, 650032, Yunnan, China
| | - Yinglei Miao
- Department of Gastroenterology, The First Affiliated Hospital of Kunming Medical University, No. 295 Xichang Road, Kunming, 650032, Yunnan, China.
- Yunnan Province Clinical Research Center for Digestive Diseases, Kunming, Yunnan, China.
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7
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Chalar C, Clivio G, Montagne J, Costábile A, Lima A, Papa NG, Berois N, Arezo MJ. Embryonic developmental arrest in the annual killifish Austrolebias charrua: A proteomic approach to diapause III. PLoS One 2021; 16:e0251820. [PMID: 34086690 PMCID: PMC8177498 DOI: 10.1371/journal.pone.0251820] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Accepted: 05/03/2021] [Indexed: 11/18/2022] Open
Abstract
Diapause is a reversible developmental arrest faced by many organisms in harsh environments. Annual killifish present this mechanism in three possible stages of development. Killifish are freshwater teleosts from Africa and America that live in ephemeral ponds, which dry up in the dry season. The juvenile and adult populations die, and the embryos remain buried in the bottom mud until the next rainy season. Thus, species survival is entirely embryo-dependent, and they are perhaps the most remarkable extremophile organisms among vertebrates. The aim of the present study was to gather information about embryonic diapauses with the use of a "shotgun" proteomics approach in diapause III and prehatching Austrolebias charrua embryos. Our results provide insight into the molecular mechanisms of diapause III. Data are available via ProteomeXchange with identifier PXD025196. We detected a diapause-dependent change in a large group of proteins involved in different functions, such as metabolic pathways and stress tolerance, as well as proteins related to DNA repair and epigenetic modifications. Furthermore, we observed a diapause-associated switch in cytoskeletal proteins. This first glance into global protein expression differences between prehatching and diapause III could provide clues regarding the induction/maintenance of this developmental arrest in A. charrua embryos. There appears to be no single mechanism underlying diapause and the present data expand our knowledge of the molecular basis of diapause regulation. This information will be useful for future comparative approaches among different diapauses in annual killifish and/or other organisms that experience developmental arrest.
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Affiliation(s)
- Cora Chalar
- Sección Bioquímica, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay
| | - Graciela Clivio
- Sección Biología Celular, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay
| | - Jimena Montagne
- Sección Biología Celular, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay
| | - Alicia Costábile
- Sección Bioquímica, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay
| | - Analía Lima
- Unidad de Bioquímica y Proteómica Analíticas, Institut Pasteur Montevideo, Montevideo, Uruguay
- Instituto de Investigaciones Biológicas Clemente Estable, Ministerio de Educación y Cultura, Montevideo, Uruguay
| | - Nicolás G. Papa
- Laboratorio de Biología Molecular de Organismos Acuáticos, Sección Biología Celular, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay
| | - Nibia Berois
- Laboratorio de Biología Molecular de Organismos Acuáticos, Sección Biología Celular, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay
| | - María José Arezo
- Laboratorio de Biología Molecular de Organismos Acuáticos, Sección Biología Celular, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay
- * E-mail:
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8
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Keratin intermediate filaments in the colon: guardians of epithelial homeostasis. Int J Biochem Cell Biol 2020; 129:105878. [PMID: 33152513 DOI: 10.1016/j.biocel.2020.105878] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 10/24/2020] [Accepted: 10/29/2020] [Indexed: 12/12/2022]
Abstract
Keratin intermediate filament proteins are major cytoskeletal components of the mammalian simple layered columnar epithelium in the gastrointestinal tract. Human colon crypt epithelial cells express keratins 18, 19 and 20 as the major type I keratins, and keratin 8 as the type II keratin. Keratin expression patterns vary between species, and mouse colonocytes express keratin 7 as a second type II keratin. Colonic keratin patterns change during cell differentiation, such that K20 increases in the more differentiated crypt cells closer to the central lumen. Keratins provide a structural and mechanical scaffold to support cellular stability, integrity and stress protection in this rapidly regenerating tissue. They participate in central colonocyte processes including barrier function, ion transport, differentiation, proliferation and inflammatory signaling. The cell-specific keratin compositions in different epithelial tissues has allowed for the utilization of keratin-based diagnostic methods. Since the keratin expression pattern in tumors often resembles that in the primary tissue, it can be used to recognize metastases of colonic origin. This review focuses on recent findings on the biological functions of mammalian colon epithelial keratins obtained from pivotal in vivo models. We also discuss the diagnostic value of keratins in chronic colonic disease and known keratin alterations in colon pathologies. This review describes the biochemical properties of keratins and their molecular actions in colonic epithelial cells and highlights diagnostic data in colorectal cancer and inflammatory bowel disease patients, which may facilitate the recognition of disease subtypes and the establishment of personal therapies in the future.
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9
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Gouveia M, Zemljič-Jokhadar Š, Vidak M, Stojkovič B, Derganc J, Travasso R, Liovic M. Keratin Dynamics and Spatial Distribution in Wild-Type and K14 R125P Mutant Cells-A Computational Model. Int J Mol Sci 2020; 21:E2596. [PMID: 32283594 PMCID: PMC7177522 DOI: 10.3390/ijms21072596] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Revised: 04/02/2020] [Accepted: 04/03/2020] [Indexed: 12/30/2022] Open
Abstract
Keratins are one of the most abundant proteins in epithelial cells. They form a cytoskeletal filament network whose structural organization seriously conditions its function. Dynamic keratin particles and aggregates are often observed at the periphery of mutant keratinocytes related to the hereditary skin disorder epidermolysis bullosa simplex, which is due to mutations in keratins 5 and 14. To account for their emergence in mutant cells, we extended an existing mathematical model of keratin turnover in wild-type cells and developed a novel 2D phase-field model to predict the keratin distribution inside the cell. This model includes the turnover between soluble, particulate and filamentous keratin forms. We assumed that the mutation causes a slowdown in the assembly of an intermediate keratin phase into filaments, and demonstrated that this change is enough to account for the loss of keratin filaments in the cell's interior and the emergence of keratin particles at its periphery. The developed mathematical model is also particularly tailored to model the spatial distribution of keratins as the cell changes its shape.
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Affiliation(s)
- Marcos Gouveia
- CFisUC, Center for Physics of the University of Coimbra, Department of Physics, University of Coimbra, R Larga, 3004-516 Coimbra, Portugal
| | - Špela Zemljič-Jokhadar
- Institute for Biophysics, Faculty of Medicine, University of Ljubljana, Vrazov trg 2, 1000 Ljubljana, Slovenia; (Š.Z.-J.); (B.S.); (J.D.)
| | - Marko Vidak
- Medical Center for Molecular Biology, Institute for Biochemistry, Faculty of Medicine, University of Ljubljana, Vrazov trg 2, 1000 Ljubljana, Slovenia; (M.V.); (M.L.)
| | - Biljana Stojkovič
- Institute for Biophysics, Faculty of Medicine, University of Ljubljana, Vrazov trg 2, 1000 Ljubljana, Slovenia; (Š.Z.-J.); (B.S.); (J.D.)
| | - Jure Derganc
- Institute for Biophysics, Faculty of Medicine, University of Ljubljana, Vrazov trg 2, 1000 Ljubljana, Slovenia; (Š.Z.-J.); (B.S.); (J.D.)
| | - Rui Travasso
- CFisUC, Center for Physics of the University of Coimbra, Department of Physics, University of Coimbra, R Larga, 3004-516 Coimbra, Portugal
| | - Mirjana Liovic
- Medical Center for Molecular Biology, Institute for Biochemistry, Faculty of Medicine, University of Ljubljana, Vrazov trg 2, 1000 Ljubljana, Slovenia; (M.V.); (M.L.)
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10
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Phosphorylation of keratin 18 serine 52 regulates mother-daughter centriole engagement and microtubule nucleation by cell cycle-dependent accumulation at the centriole. Histochem Cell Biol 2020; 153:307-321. [PMID: 32078038 DOI: 10.1007/s00418-020-01849-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/23/2020] [Indexed: 12/11/2022]
Abstract
Serine-52 (Ser52) is the major physiologic site of keratin 18 (K18) phosphorylation. Here, we report that serine-52 phosphorylated K18 (phospho-Ser52 K18) accumulated on centrosomes in a cell cycle-dependent manner. Moreover, we found that phospho-Ser52 K18 was located at the proximal end of the mother centriole. Transfection with the K18 Ser52 → Ala (K18 S52A) mutant prevented centriole localization of phospho-Ser52 K18 and resulted in separation of the mother-daughter centrioles. Inhibition of microtubule polymerization led to the disappearance of aggregated phospho-Ser52 K18 on the centrosome; removal of inhibitors resulted in reaccumulation of phospho-Ser52 K18 in microtubule-organizing centers. Transfection with a K18 S52A mutant inhibited microtubule nucleation. These results reveal a cell cycle-dependent change in centrosome localization of phospho-Ser52 k18 and strongly suggest that the phosphorylation status of Ser52 K18 of mother centrioles plays a critical role in maintaining a tight engagement between mother and daughter centrioles and also contributes to microtubule nucleation.
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11
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Geesala R, Schanz W, Biggs M, Dixit G, Skurski J, Gurung P, Meyerholz DK, Elliott D, Issuree PD, Maretzky T. Loss of RHBDF2 results in an early-onset spontaneous murine colitis. J Leukoc Biol 2019; 105:767-781. [PMID: 30694569 DOI: 10.1002/jlb.4a0718-283rr] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Revised: 01/16/2019] [Accepted: 01/17/2019] [Indexed: 12/16/2022] Open
Abstract
Inflammatory bowel disease (IBD) is a heterogeneous group of inflammation-mediated pathologies that include Crohn's disease and ulcerative colitis and primarily affects the colon and small intestine. Previous studies have shown that a disintegrin and metalloprotease (ADAM) 17, a membrane-bound sheddase, capable of cleaving the proinflammatory cytokine TNF and epidermal growth factor receptor ligands, plays a critical role in maintaining gut homeostasis and modulating intestinal inflammation during IBD. Rhomboid 5 homolog 2 (RHBDF2), a catalytically inactive member of the rhomboid family of intramembrane serine proteases, was recently identified as a crucial regulator of ADAM17. Here, we assessed the role of RHBDF2 in the development of colitis in the context of IL10 deficiency. Il10-/- /Rhbdf2-/- mice developed spontaneous colitis and experienced severe weight loss starting at 8 wk of age, without the need for exogenous triggers. Severity of disease pathology in Il10-/- /Rhbdf2-/- mice correlated with a dysbiotic gut microbiota and elevated Th1-associated immune responses with increased interferon gamma and IL2 production. In addition, Il10-/- /Rhbdf2-/- mice failed to maintain their epithelial cell homeostasis, although the intestinal epithelial barrier of Rhbdf2-/- mice is intact and loss of Rhbdf2 did not significantly exacerbate sensitivity to dextran sulfate sodium-induced colitis, suggesting differences in the underlying disease pathway of intestinal inflammation in this model. Taken together, our results demonstrate a critical regulatory role for RHBDF2 in the maintenance of the unique homeostasis between intestinal microbiota and host immune responses in the gut that is dysregulated during the pathogenesis of IBD.
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Affiliation(s)
- Ramasatyaveni Geesala
- Inflammation Program, Roy J. and Lucille A. Carver College of Medicine University of Iowa, Iowa City, Iowa, USA.,Department of Internal Medicine, Roy J. and Lucille A. Carver College of Medicine University of Iowa, Iowa City, Iowa, USA
| | - Willow Schanz
- Inflammation Program, Roy J. and Lucille A. Carver College of Medicine University of Iowa, Iowa City, Iowa, USA.,Department of Internal Medicine, Roy J. and Lucille A. Carver College of Medicine University of Iowa, Iowa City, Iowa, USA
| | - Mikayla Biggs
- Inflammation Program, Roy J. and Lucille A. Carver College of Medicine University of Iowa, Iowa City, Iowa, USA.,Department of Internal Medicine, Roy J. and Lucille A. Carver College of Medicine University of Iowa, Iowa City, Iowa, USA
| | - Garima Dixit
- Inflammation Program, Roy J. and Lucille A. Carver College of Medicine University of Iowa, Iowa City, Iowa, USA.,Department of Internal Medicine, Roy J. and Lucille A. Carver College of Medicine University of Iowa, Iowa City, Iowa, USA
| | - Joseph Skurski
- Inflammation Program, Roy J. and Lucille A. Carver College of Medicine University of Iowa, Iowa City, Iowa, USA.,Department of Internal Medicine, Roy J. and Lucille A. Carver College of Medicine University of Iowa, Iowa City, Iowa, USA.,Immunology Graduate Program, Iowa City, Iowa, USA
| | - Prajwal Gurung
- Inflammation Program, Roy J. and Lucille A. Carver College of Medicine University of Iowa, Iowa City, Iowa, USA.,Department of Internal Medicine, Roy J. and Lucille A. Carver College of Medicine University of Iowa, Iowa City, Iowa, USA.,Immunology Graduate Program, Iowa City, Iowa, USA
| | - David K Meyerholz
- Department of Pathology, Roy J. and Lucille A. Carver College of Medicine, Iowa City, Iowa, USA
| | - David Elliott
- Department of Veterans Affairs Medical Center, Roy J. and Lucille A. Carver College of Medicine, Iowa City, Iowa, USA
| | - Priya D Issuree
- Inflammation Program, Roy J. and Lucille A. Carver College of Medicine University of Iowa, Iowa City, Iowa, USA.,Department of Internal Medicine, Roy J. and Lucille A. Carver College of Medicine University of Iowa, Iowa City, Iowa, USA
| | - Thorsten Maretzky
- Inflammation Program, Roy J. and Lucille A. Carver College of Medicine University of Iowa, Iowa City, Iowa, USA.,Department of Internal Medicine, Roy J. and Lucille A. Carver College of Medicine University of Iowa, Iowa City, Iowa, USA.,Immunology Graduate Program, Iowa City, Iowa, USA.,Holden Comprehensive Cancer Center, University of Iowa, Iowa City, Iowa, USA
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Geisler F, Coch RA, Richardson C, Goldberg M, Denecke B, Bossinger O, Leube RE. The intestinal intermediate filament network responds to and protects against microbial insults and toxins. Development 2019; 146:dev.169482. [PMID: 30630824 DOI: 10.1242/dev.169482] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Accepted: 12/19/2018] [Indexed: 12/12/2022]
Abstract
The enrichment of intermediate filaments in the apical cytoplasm of intestinal cells is evolutionarily conserved, forming a sheath that is anchored to apical junctions and positioned below the microvillar brush border, which suggests a protective intracellular barrier function. To test this, we used Caenorhabditis elegans, the intestinal cells of which are endowed with a particularly dense intermediate filament-rich layer that is referred to as the endotube. We found alterations in endotube structure and intermediate filament expression upon infection with nematicidal B. thuringiensis or treatment with its major pore-forming toxin crystal protein Cry5B. Endotube impairment due to defined genetic mutations of intermediate filaments and their regulators results in increased Cry5B sensitivity as evidenced by elevated larval arrest, prolonged time of larval development and reduced survival. Phenotype severity reflects the extent of endotube alterations and correlates with reduced rescue upon toxin removal. The results provide in vivo evidence for a major protective role of a properly configured intermediate filament network as an intracellular barrier in intestinal cells. This notion is further supported by increased sensitivity of endotube mutants to oxidative and osmotic stress.
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Affiliation(s)
- Florian Geisler
- Institute of Molecular and Cellular Anatomy, RWTH Aachen University, 52074 Aachen, Germany
| | - Richard A Coch
- Institute of Molecular and Cellular Anatomy, RWTH Aachen University, 52074 Aachen, Germany
| | - Christine Richardson
- School of Biological and Biomedical Sciences, Department of Biosciences, Durham University, Durham DH1 3LE, UK
| | - Martin Goldberg
- School of Biological and Biomedical Sciences, Department of Biosciences, Durham University, Durham DH1 3LE, UK
| | - Bernd Denecke
- Genomics Facility, IZKF Aachen, RWTH Aachen University, 52074 Aachen, Germany
| | - Olaf Bossinger
- Institute of Molecular and Cellular Anatomy, RWTH Aachen University, 52074 Aachen, Germany
| | - Rudolf E Leube
- Institute of Molecular and Cellular Anatomy, RWTH Aachen University, 52074 Aachen, Germany
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Geisler F, Gerhardus H, Carberry K, Davis W, Jorgensen E, Richardson C, Bossinger O, Leube RE. A novel function for the MAP kinase SMA-5 in intestinal tube stability. Mol Biol Cell 2016; 27:3855-3868. [PMID: 27733627 PMCID: PMC5170608 DOI: 10.1091/mbc.e16-02-0099] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Revised: 09/26/2016] [Accepted: 10/05/2016] [Indexed: 01/19/2023] Open
Abstract
In vivo evidence links SMA-5 to the maintenance of the apical domain in the Caenorhabditis elegans intestine. sma-5 mutations induce morphological and biochemical changes of the intermediate filament system, demonstrating the close relationship between posttranslational modification and structural integrity of the evolutionarily conserved intestinal cytoskeleton. Intermediate filaments are major cytoskeletal components whose assembly into complex networks and isotype-specific functions are still largely unknown. Caenorhabditis elegans provides an excellent model system to study intermediate filament organization and function in vivo. Its intestinal intermediate filaments localize exclusively to the endotube, a circumferential sheet just below the actin-based terminal web. A genetic screen for defects in the organization of intermediate filaments identified a mutation in the catalytic domain of the MAP kinase 7 orthologue sma-5(kc1). In sma-5(kc1) mutants, pockets of lumen penetrate the cytoplasm of the intestinal cells. These membrane hernias increase over time without affecting epithelial integrity and polarity. A more pronounced phenotype was observed in the deletion allele sma-5(n678) and in intestine-specific sma-5(RNAi). Besides reduced body length, an increased time of development, reduced brood size, and reduced life span were observed in the mutants, indicating compromised food uptake. Ultrastructural analyses revealed that the luminal pockets include the subapical cytoskeleton and coincide with local thinning and gaps in the endotube that are often enlarged in other regions. Increased intermediate filament phosphorylation was detected by two-dimensional immunoblotting, suggesting that loss of SMA-5 function leads to reduced intestinal tube stability due to altered intermediate filament network phosphorylation.
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Affiliation(s)
- Florian Geisler
- Institute of Molecular and Cellular Anatomy, RWTH Aachen University, 52074 Aachen, Germany
| | - Harald Gerhardus
- Institute of Molecular and Cellular Anatomy, RWTH Aachen University, 52074 Aachen, Germany
| | - Katrin Carberry
- Institute of Molecular and Cellular Anatomy, RWTH Aachen University, 52074 Aachen, Germany
| | - Wayne Davis
- Department of Biology and Howard Hughes Medical Institute, University of Utah, Salt Lake City, UT 84112-0840
| | - Erik Jorgensen
- Department of Biology and Howard Hughes Medical Institute, University of Utah, Salt Lake City, UT 84112-0840
| | - Christine Richardson
- School of Biological and Biomedical Sciences, Durham University, Durham DH1 3LE, United Kingdom
| | - Olaf Bossinger
- Institute of Molecular and Cellular Anatomy, RWTH Aachen University, 52074 Aachen, Germany
| | - Rudolf E Leube
- Institute of Molecular and Cellular Anatomy, RWTH Aachen University, 52074 Aachen, Germany
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14
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Babkair H, Yamazaki M, Uddin MS, Maruyama S, Abé T, Essa A, Sumita Y, Ahsan MS, Swelam W, Cheng J, Saku T. Aberrant expression of the tight junction molecules claudin-1 and zonula occludens-1 mediates cell growth and invasion in oral squamous cell carcinoma. Hum Pathol 2016; 57:51-60. [PMID: 27436828 DOI: 10.1016/j.humpath.2016.07.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Revised: 06/10/2016] [Accepted: 07/02/2016] [Indexed: 01/12/2023]
Abstract
We reported that altered cell contact mediated by E-cadherin is an initial event in the pathogenesis of oral epithelial malignancies. To assess other effects of cell adhesion, we examined the expression levels of tight junction (TJ) molecules in oral carcinoma in situ (CIS) and squamous cell carcinoma (SCC). To identify changes in the expression of TJ molecules, we conducted an analysis of the immunohistochemical profiles of claudin-1 (CLDN-1) and zonula occludens-1 (ZO-1) in surgical specimens acquired from patients with oral SCC containing foci of epithelial dysplasia or from patients with CIS. We used immunofluorescence, Western blotting, reverse-transcription polymerase chain reaction, and RNA interference to evaluate the functions of CLDN-1 and ZO-1 in cultured oral SCC cells. TJ molecules were not detected in normal oral epithelial tissues but were expressed in SCC/CIS cells. ZO-1 was localized within the nucleus of proliferating cells. When CLDN-1 expression was inhibited by transfecting cells with specific small interference RNAs, SCC cells dissociated, and their ability to proliferate and invade Matrigel was inhibited. In contrast, although RNA interference-mediated inhibition of ZO-1 expression did not affect cell morphology, it inhibited cell proliferation and invasiveness. Our findings indicated that the detection of TJ molecules in the oral epithelia may serve as a marker for the malignant phenotype of cells in which CLDN-1 regulates proliferation and invasion.
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Affiliation(s)
- Hamzah Babkair
- Division of Oral Pathology, Niigata University Graduate School of Medical and Dental Sciences, Niigata 951-8514, Japan; Division of Oral Pathology, Department of Oral Basic and Clinical Sciences, College of Dentistry, Taibah University, Medina 41311, Saudi Arabia
| | - Manabu Yamazaki
- Division of Oral Pathology, Niigata University Graduate School of Medical and Dental Sciences, Niigata 951-8514, Japan.
| | - Md Shihab Uddin
- Division of Oral Pathology, Niigata University Graduate School of Medical and Dental Sciences, Niigata 951-8514, Japan
| | - Satoshi Maruyama
- Oral Pathology Section, Department of Surgical Pathology, Niigata University Hospital, Niigata 951-8520, Japan
| | - Tatsuya Abé
- Division of Oral Pathology, Niigata University Graduate School of Medical and Dental Sciences, Niigata 951-8514, Japan; Oral Pathology Section, Department of Surgical Pathology, Niigata University Hospital, Niigata 951-8520, Japan
| | - Ahmed Essa
- Division of Oral Pathology, Niigata University Graduate School of Medical and Dental Sciences, Niigata 951-8514, Japan
| | - Yoshimasa Sumita
- Division of Oral Pathology, Niigata University Graduate School of Medical and Dental Sciences, Niigata 951-8514, Japan
| | - Md Shahidul Ahsan
- Division of Oral Pathology, Niigata University Graduate School of Medical and Dental Sciences, Niigata 951-8514, Japan
| | - Wael Swelam
- Division of Oral Pathology, Department of Oral Basic and Clinical Sciences, College of Dentistry, Taibah University, Medina 41311, Saudi Arabia
| | - Jun Cheng
- Division of Oral Pathology, Niigata University Graduate School of Medical and Dental Sciences, Niigata 951-8514, Japan
| | - Takashi Saku
- Division of Oral Pathology, Niigata University Graduate School of Medical and Dental Sciences, Niigata 951-8514, Japan; Oral Pathology Section, Department of Surgical Pathology, Niigata University Hospital, Niigata 951-8520, Japan
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15
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Coch RA, Leube RE. Intermediate Filaments and Polarization in the Intestinal Epithelium. Cells 2016; 5:E32. [PMID: 27429003 PMCID: PMC5040974 DOI: 10.3390/cells5030032] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Revised: 07/05/2016] [Accepted: 07/06/2016] [Indexed: 01/02/2023] Open
Abstract
The cytoplasmic intermediate filament cytoskeleton provides a tissue-specific three-dimensional scaffolding with unique context-dependent organizational features. This is particularly apparent in the intestinal epithelium, in which the intermediate filament network is localized below the apical terminal web region and is anchored to the apical junction complex. This arrangement is conserved from the nematode Caenorhabditis elegans to humans. The review summarizes compositional, morphological and functional features of the polarized intermediate filament cytoskeleton in intestinal cells of nematodes and mammals. We emphasize the cross talk of intermediate filaments with the actin- and tubulin-based cytoskeleton. Possible links of the intermediate filament system to the distribution of apical membrane proteins and the cell polarity complex are highlighted. Finally, we discuss how these properties relate to the establishment and maintenance of polarity in the intestine.
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Affiliation(s)
- Richard A Coch
- Institute of Molecular and Cellular Anatomy, RWTH Aachen University, Wendlingweg 2, Aachen 52074, Germany.
| | - Rudolf E Leube
- Institute of Molecular and Cellular Anatomy, RWTH Aachen University, Wendlingweg 2, Aachen 52074, Germany.
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Asghar MN, Priyamvada S, Nyström JH, Anbazhagan AN, Dudeja PK, Toivola DM. Keratin 8 knockdown leads to loss of the chloride transporter DRA in the colon. Am J Physiol Gastrointest Liver Physiol 2016; 310:G1147-54. [PMID: 27125276 PMCID: PMC4935477 DOI: 10.1152/ajpgi.00354.2015] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/07/2015] [Accepted: 04/23/2016] [Indexed: 02/06/2023]
Abstract
Keratins (K) are intermediate filament proteins important in protection from stress. The roles of keratins in the intestine are not clear, but K8 knockout (K8(-/-)) mice develop a Th2-type colonic inflammation, epithelial hyperproliferation, and mild diarrhea caused by a keratin level-dependent decrease in short-circuit current and net sodium and chloride absorption in the distal colon. The lack of K8 leads to mistargeting or altered levels of membrane proteins in colonocytes; however, the main transporter responsible for the keratin-related ion transport defect is unknown. We here analyzed protein and mRNA levels of candidate ion transporters CFTR, PAT-1, NHE-3, and DRA in ileum, cecum, and proximal and distal colon. Although no differences were observed for CFTR, PAT-1, or NHE-3, DRA mRNA levels were decreased by three- to fourfold and DRA protein was almost entirely lost in K8(-/-) cecum and proximal and distal colon compared with K8(+/+), whereas the levels in ileum were normal. In K8(+/-) mice, DRA mRNA levels were unaltered, while decreased DRA protein levels were detected in the proximal colon. Immunofluorescence staining confirmed the loss of DRA in K8(-/-) distal colon, while K8(+/-) displayed a similar but more patchy apical DRA distribution compared with K8(+/+) DRA was similarly decreased when K8 was knocked down in Caco-2 cells, confirming that K8 levels modulate DRA levels in an inflammation-independent manner. Taken together, the loss of DRA in the K8(-/-) mouse colon and cecum explains the dramatic chloride transport defect and diarrheal phenotype after K8 inactivation and identifies K8 as a novel regulator of DRA.
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Affiliation(s)
- M. Nadeem Asghar
- 1Cell Biology, Biosciences, Faculty of Science and Engineering, Åbo Akademi University and Turku Center for Disease Modeling, University of Turku, Turku, Finland; and
| | - Shubha Priyamvada
- 2University of Illinois at Chicago, Jesse Brown Veterans Affairs Medical Center, Chicago, Illinois
| | - Joel H. Nyström
- 1Cell Biology, Biosciences, Faculty of Science and Engineering, Åbo Akademi University and Turku Center for Disease Modeling, University of Turku, Turku, Finland; and
| | | | - Pradeep K. Dudeja
- 2University of Illinois at Chicago, Jesse Brown Veterans Affairs Medical Center, Chicago, Illinois
| | - Diana M. Toivola
- 1Cell Biology, Biosciences, Faculty of Science and Engineering, Åbo Akademi University and Turku Center for Disease Modeling, University of Turku, Turku, Finland; and
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Salas PJ, Forteza R, Mashukova A. Multiple roles for keratin intermediate filaments in the regulation of epithelial barrier function and apico-basal polarity. Tissue Barriers 2016; 4:e1178368. [PMID: 27583190 PMCID: PMC4993576 DOI: 10.1080/21688370.2016.1178368] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Revised: 04/05/2016] [Accepted: 04/07/2016] [Indexed: 12/27/2022] Open
Abstract
As multicellular organisms evolved a family of cytoskeletal proteins, the keratins (types I and II) expressed in epithelial cells diversified in more than 20 genes in vertebrates. There is no question that keratin filaments confer mechanical stiffness to cells. However, such a number of genes can hardly be explained by evolutionary advantages in mechanical features. The use of transgenic mouse models has revealed unexpected functional relationships between keratin intermediate filaments and intracellular signaling. Accordingly, loss of keratins or mutations in keratins that cause or predispose to human diseases, result in increased sensitivity to apoptosis, regulation of innate immunity, permeabilization of tight junctions, and mistargeting of apical proteins in different epithelia. Precise mechanistic explanations for these phenomena are still lacking. However, immobilization of membrane or cytoplasmic proteins, including chaperones, on intermediate filaments (“scaffolding”) appear as common molecular mechanisms and may explain the need for so many different keratin genes in vertebrates.
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Affiliation(s)
- Pedro J Salas
- Department of Cell Biology, Miller School of Medicine, University of Miami , Miami, FL, USA
| | - Radia Forteza
- Department of Cell Biology, Miller School of Medicine, University of Miami , Miami, FL, USA
| | - Anastasia Mashukova
- Department of Cell Biology, Miller School of Medicine, University of Miami, Miami, FL, USA; Department of Physiology, Nova Southeastern University, Fort Lauderdale, FL, USA
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19
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The amount of keratins matters for stress protection of the colonic epithelium. PLoS One 2015; 10:e0127436. [PMID: 26000979 PMCID: PMC4441500 DOI: 10.1371/journal.pone.0127436] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2015] [Accepted: 04/15/2015] [Indexed: 11/19/2022] Open
Abstract
Keratins (K) are important for epithelial stress protection as evidenced by keratin mutations predisposing to human liver diseases and possibly inflammatory bowel diseases. A role for K8 in the colon is supported by the ulcerative colitis-phenotype with epithelial hyperproliferation and abnormal ion transport in K8-knockout (K8-/-) mice. The heterozygote knockout (K8+/-) colon appears normal but displays a partial ion transport-defect. Characterizing the colonic phenotype we show that K8+/- colon expresses ~50% less keratins compared to K8 wild type (K8+/+) but de novo K7 expression is observed in the top-most cells of the K8+/- and K8-/- crypts. The K8+/- colonic crypts are significantly longer due to increased epithelial hyperproliferation, but display no defects in apoptosis or inflammation in contrast to K8-/-. When exposed to colitis using the dextran sulphate sodium-model, K8+/- mice showed higher disease sensitivity and delayed recovery compared to K8+/+ littermates. Therefore, the K8+/- mild colonic phenotype correlates with decreased keratin levels and increased sensitivity to experimental colitis, suggesting that a sufficient amount of keratin is needed for efficient stress protection in the colonic epithelia.
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Trek1 contributes to maintaining nasal epithelial barrier integrity. Sci Rep 2015; 5:9191. [PMID: 25778785 PMCID: PMC7365316 DOI: 10.1038/srep09191] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2014] [Accepted: 02/24/2015] [Indexed: 02/07/2023] Open
Abstract
Epithelial barrier integrity is critical to maintain the homeostasis in the body. The regulatory mechanism of the epithelial barrier function has not been fully understood. This study aims to elucidate the role of the TWIK-related potassium channel-1 (Trek1) in the regulation of the epithelial barrier function of the nasal mucosa. In this study, the levels of Trek1 were assessed by real time RT-PCR and Western blotting. The epithelial barrier function of the rat nasal epithelia was evaluated by the Ussing chamber system. The results showed that Trek1 was detected in the human and rat nasal epithelia, which were significantly lower in patients and rats with allergic rhinitis than that in healthy controls. Exposure to the signature T helper 2 cytokine, interleukin (IL)-4, markedly suppressed the expression of Trek1 in the nasal mucosa via up regulating the expression of the histone deacetylase (HDAC)1. The IL-4-induced rat nasal epithelial barrier dysfunction could be blocked by HDAC1 inhibitor (Trichostatin A), or sodium butyrate, or administration of Clostridium Butyricum. We conclude that Trek1 is critical to maintain the nasal epithelial barrier function.
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