Antidiarrheal efficacy of a quinazolin CFTR inhibitor on human intestinal epithelial cell and in mouse model of cholera

Abstract

Objective:This study aimed to evaluate the antidiarrheal efficacy and pharmacological properties of ethyl 2-(4-oxo-3-o-tolyl-3,4-dihydroquinazolin-2-ylthio)acetate (DQA) as an inhibitor of cystic fibrosis transmembrane conductance regulator protein (CFTR) both in vitro and in vivo.Materials and Methods:The effects of DQA on CFTR function and cell viability were investigated in Fisher rat thyroid (FRT) cells expressing human CFTR and human intestinal epithelial T84 cells by short-circuit current measurements and MTT assays, respectively. In vivo antidiarrheal efficacy of DQA was evaluated in a closed loop model of cholera in mice.Results:In permeabilized FRT cells, apical chloride current induced by CFTR agonists (10 μM forskolin, 100 μM CPT-cAMP, and 20 μM apigenin) was inhibited by DQA with IC50 ~ 20 μM and complete inhibition at 200 μM. The inhibitory effect was reversible and not associated with cytotoxicity to FRT cells (5–500 μM DQA for 24 h). Likewise, DQA effectively inhibited both forskolin and cholera toxin-induced transepithelial chloride secretion in T84 cells. In mice, intraluminal injection of 100 μM DQA reduced cholera toxin (1 μg/closed loop)-induced intestinal fluid secretion by 85% without affecting intestinal fluid absorption.Conclusions:DQA represents a new class of small molecule CFTR inhibitor with potential application in treatment of cholera.

Genistein-induced fluid accumulation in ovariectomised rats' uteri is associated with increased cystic fibrosis transmembrane regulator expression

“…Our hypothesis that CFTR is involved in uterine fluid secretion is also supported by the observation that a marked increase in uterine CFTR expression occurs in diseases related to excessive fluid accumulation in the uterus, such as hydrosalpinx 45 . Apart from the uterus, CFTR has been reported to mediate fluid secretion in the small intestine 46 , submucosal glands 47 , and salivary glands 48 . Therefore, it is likely that the observed increase in fluid accumulation within the uterine lumen was due to genistein-induced CFTR up-regulation.…”