Evidence for a causal link between adaptor protein PDZK1 downregulation and Na -H exchanger NHE3 dysfunction in human and murine colitisReportar como inadecuado




Evidence for a causal link between adaptor protein PDZK1 downregulation and Na -H exchanger NHE3 dysfunction in human and murine colitis - Descarga este documento en PDF. Documentación en PDF para descargar gratis. Disponible también para leer online.

Journal Title:

Pflügers Archiv European Journal of Physiology

Volume:

Volume 467, Number 8

Publisher:

Springer Verlag Germany | 2014-10-02, Pages 1795-1807

Type of Work:

Article | Final Publisher PDF

Abstract: A dysfunction of the Na+<-sup>-H+<-sup> exchanger isoform 3 NHE3 significantly contributes to the reduced salt absorptive capacity of the inflamed intestine. We previously reported a strong decrease in the NHERF family member PDZK1 NHERF3, which binds to NHE3 and regulates its function in a mouse model of colitis. The present study investigates whether a causal relationship exists between the decreased PDZK1 expression and the NHE3 dysfunction in human and murine intestinal inflammation. Biopsies from the colon of patients with ulcerative colitis, murine inflamed ileal and colonic mucosa, NHE3-transfected Caco-2BBe colonic cells with short hairpin RNA shRNA knockdown of PDZK1, and Pdzk1-gene-deleted mice were studied. PDZK1 mRNA and protein expression was strongly decreased in inflamed human and murine intestinal tissue as compared to inactive disease or control tissue, whereas that of NHE3 or NHERF1 was not. Inflamed human and murine intestinal tissues displayed correct brush border localization of NHE3 but reduced acid-activated NHE3 transport activity. A similar NHE3 transport defect was observed when PDZK1 protein content was decreased by shRNA knockdown in Caco-2BBe cells or when enterocyte PDZK1 protein content was decreased to similar levels as found in inflamed mucosa by heterozygote breeding of Pdzk1-gene-deleted and WT mice. We conclude that a decrease in PDZK1 expression, whether induced by inflammation, shRNA-mediated knockdown, or heterozygous breeding, is associated with a decreased NHE3 transport rate in human and murine enterocytes. We therefore hypothesize that inflammation-induced loss of PDZK1 expression may contribute to the NHE3 dysfunction observed in the inflamed intestine.

Subjects: Health Sciences, Immunology - Health Sciences, General - Research Funding: This work was supported by a grant from the German Science Foundations grants SFB621-C9 and Se460-9-6 to U.S. and by the Volkswagenstiftung to U.S. and the Hochschulinterne Leistungsförderung HiLF from Hannover Medical School to S.Y



Keywords: Science and Technology - Life Sciences and Biomedicine - Physiology - pH regulation - Sodium absorption - Electrolyte transport - Intestinal inflammation - Inflammatory bowel disease - INFLAMMATORY-BOWEL-DISEASE - INTESTINAL ION-TRANSPORT - ULCERATIVE-COLITIS - DEFICIENT MICE - UP-REGULATION - DIARRHEA - INHIBITION - EXPRESSION - MODEL - COLON -



Autor: Sunil Yeruva, Giriprakash Chodisetti, Min Luo, Mingmin Chen, Ayhan Cinar, Lisa Ludolph, Maria Luennemann, Julia Goldstein, Anurag

Fuente: https://open.library.emory.edu/



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