Mori Cortex regulates P-glycoprotein in Caco-2 cells and colons from rats with experimental colitis via direct and gut microbiota-mediated mechanisms

Abstract

ac P-Glycoprotein dysregulation and microbial imbalance have been implicated in inflammatory bowel diseases. Here we found that oral dosing of Mori Cortex, the root bark of Morus alba L. markedly alleviated inflammatory responses, reinstated microbial balance, and enhanced P-glycoprotein (P-gp) expression in rat colitis (UC) induced by oral administration of dextran sulfate sodium. The effects of Mori Cortex extract (MCE) on colon P-gp were examined using Caco-2 cells which revealed a timedependent regulatory profile. The distinct effects on P-gp by individual main components may account for the direct biphasic effects of MCE. The involvement of gut microbiota in P-gp regulation by MCE was assessed by incubating the culture supernatant (CS) of fecal bacteria from normal, UC or MCE pretreated rats with Caco-2 cells. Interestingly, compared to normal CS, UC CS but not MCE CS diminished P-gp expression in Caco-2 cells, and this down-regulation could be reversed by pretreatment of Caco-2 cells with MCE. Moreover, MCE CS treated Caco-2 cells generated proinflammatory IL-1b and IL-8 comparable to that of the normal group and lower than the UC group, whereas, the anti-inflammatory IL-10 stimulated by MCE CS was significantly higher than the UC CS. In conclusion, MCE alleviated colitis-like symptoms and enhanced the intestinal epithelial integrity (P-gp up-regulation) in experimental colitis. The mechanisms involve both a direct effect and a gut microbiota-mediated pathway.

Berberine Upregulates P-Glycoprotein in Human Caco-2 Cells and in an Experimental Model of Colitis in the Rat via Activation of Nrf2-Dependent Mechanisms

“…The DAI, including stool consistency, body weight loss, and gross bleeding, was elevated after DSS administration for 2 days (Fig. 1A), in agreement with our previous study (Jing et al, 2016). Rats with DSS-induced colitis treated with berberine (10 and 40 mg/kg) for 7 days showed reduced responses to DSS and lowering of DAI scores (Fig.…”

“…After DSS administration, we also observed increased levels of proinflammatory cytokines in colon tissues (TNF-a, IL-1b, and IL-6). These findings are similar to those of our previous study involving rats with colitis induced by 5% DSS administration (Jing et al, 2016). In this study, berberine treatment alleviated colitis symptoms in a dose-dependent manner (Figs.…”

“…Splenomegaly is common among patients with UC (Ashrafi et al, 2014), and spleen weight represents an index of systemic inflammation (Antonioli et al, 2007). In agreement with earlier studies (Jing et al, 2016), enlarged spleens were observed in DSS-treated rats, and this was significantly attenuated by berberine (10 and 40 mg/kg) treatment (Fig. 1, B and C).…”

“…The colon tissues were removed and fixed with 10% formalin solution overnight. Histologic sections were stained with H&E. Colon injury and inflammation were graded on a 0-5 scale, as described in previous reports (Maeda et al, 2005;Jing et al, 2016).…”

“…Western Blotting Analysis. Cytoplasmic and nuclear extracts of colon tissues and cells were prepared as described in our previous reports (Jing et al, 2016). Proteins of interest in the cytoplasmic and nuclear fractions of colon tissues or cells were measured by Western blotting as described in our previous report (Jing et al, 2016(Jing et al, , 2017 using the following antibodies: anti P-gp (1:400, cat.…”