Downregulation of intestinal Mdr-1 in obese mice: impact on its barrier function and role of TNF-α receptor 1 signaling

BARRANCO, MARIA MANUELA; PERDOMO, VIRGINIA GABRIELA; ZECCHINATI, FELIPE; MANARIN, ROMINA; MASSUH, GRETA; SIGAL, NICOLAS; VIGNADUZZO, SILVANA; MOTTINO, ALDO DOMINGO; VILLANUEVA, SILVINA STELLA MARIS; GARCÍA, FABIANA

NUTRITION

ELSEVIER SCIENCE INC

Lugar: Amsterdam; Año: 2023

0899-9007

Multidrug resistance transporter-1 (Mdr-1) is a relevant component of the intestinal transcellular barrier by decreasing oral drugs absorption, thus modulating their bioavailability. Obese patients with metabolic disorders take medicaments that are subjected to intestinal metabolism and Mdr-1-dependent barrier. Objective: Evaluate the effect of a high-fat diet (HFD, 40% fat for 16 weeks) on Mdr-1 expression and transport activity, in C57BL/6 (C57) male mice. Comparable studies were performed in TNF-α receptor 1 knockout mice (R1KO) to delineate a possible role of TNF-α signaling. Methods: mRNA expression was evaluated by real-time PCR, and protein levels by immunohistochemistry. Mdr-1 activity was assessed using the everted intestinal sac model, with Rhodamine 123 as substrate. Statistical comparisons were done by student-t test or one-way ANOVA followed by the post hoc Tukey test.Results: There was a decrease in ileal mRNA expression of Mdr1a and Mdr1b of 62% and 66% respectively in C57-HFD as compared with controls. Immunohistochemical studies confirmed downregulation of Mdr-1 in situ. These results correlated with a 48% decrease in the basolateral to apical transport of Rhodamine 123. In contrast, R1KO-HFD neither modified intestinal Mdr-1 mRNAs, nor its protein expression or activity. Besides, C57-HFD showed elevated intestinal TNF-α mRNA levels, whereas in R1KO this cytokine was not detectable with either diet. Conclusion: We demonstrate for the first time an impairment of the Mdr-1 intestinal barrier function induced by HFD as a consequence of both Mdr-1 gene homologues downregulation, resulting in impaired Mdr-1 protein expression. TNF-α receptor 1 signaling-mediated inflammatory response is likely involved.