Plumbagin Prevents Secretory Diarrhea by Inhibiting CaCC and CFTR Channel Activities

Abstract

Secretory diarrhea, which primarily originates through intestinal pathogens and viruses, is a health burden in many regions worldwide. Enterocyte Cl− channels, as the final step in enterotoxin-induced fluid secretion, constitute an attractive class of targets for diarrhea therapy. Chloride channel inhibitors have become a new class of candidates for antisecretion and anti-intestinal motility agents. In the present study, we identified plumbagin as a transmembrane protein 16A (TMEM16A) inhibitor in a cell-based fluorescence-quenching assay, and the IC50 value was ∼12.46 µM. Short-circuit current measurements showed that plumbagin reversibly inhibited the Eact-induced Cl− current on the apical side of TMEM16A-transfected Fischer rat thyroid (FRT) cells with no significant effect on cytoplasmic Ca2+ signaling. Notably, plumbagin also inhibited the activity of intestinal epithelial calcium-activated chloride channel (CaCC) and cystic fibrosis transmembrane conductance regulator (CFTR) in both HT-29 cells and mouse colons, but had no effects on the activity of the Na+-K+ ATPase or K+ channels. In in vivo experiments, the administration of plumbagin reduced both Escherichia coli heat-stable enterotoxin (STa)- and cholera toxin (CT)-induced intestinal fluid secretion. In neonatal mouse models of CT- and rotavirus infection-induced diarrhea, 0.4 µg plumbagin inhibited secretory diarrhea by >40% and 50%, respectively, without affecting intestinal epithelial integrity or the rotaviral infection. In addition, plumbagin exerted inhibitory effects on the vasoactive intestinal peptide (VIP)-, prostaglandin E2 (PGE2)-, and 5-hydroxytryptamine (5-HT)-stimulated Cl− currents. In the evaluations of intestinal motility, plumbagin significantly delayed intestinal motility and inhibited intestinal smooth muscle contractility without an evident impact on contractive frequency. Collectively, our results indicate that plumbagin inhibits both Ca2+- and cAMP-activated Cl− channels, accounting for the mechanisms of plumbagin inhibition of chloride secretion and intestinal motility. Thus, plumbagin can be a lead compound in the treatment of CT-induced, Traveler’s, and rotaviral diarrhea, as well as other types of secretory diarrhea that result from excessive intestinal fluid secretion and increased intestinal peristalsis.

Effect of lentivirus-mediated CFTR overexpression on oxidative stress injury and inflammatory response in the lung tissue of COPD mouse model

“…It is a type of Cl − channel in epithelial cell regulated by phosphorylation and is expressed in many apical membranes of epithelium related to fluid secretion and absorption [7]. CFTR, as a chloride channel activated by cAMP, participates in the secretion and transport of transepithelial ion and water molecule in endothelial cells through Cl − transmembrane transport and serves a critical role in the cell proliferation, migration, and ion concentration adjustment [8].…”

Treading a HOSTile path: Mapping the dynamic landscape of host cell–rotavirus interactions to explore novel host-directed curative dimensions

“…Secretory NSP4dependent [Ca 2+ ] cyto elevation and subsequent activation of calcium-activated chloride channels (CaCC) (such as TMEM16A) leading to augmented Ca 2+ -dependent Cl − secretion in the intestinal lumen has been considered to be a pivotal regulatory component of RV-induced secretory diarrhea [219] (Figure 4b). Consistently, inhibition of CaCC by plant products (Plumbagin from Plumbago zeylanica L., a herbal extract Krisanaklan, Shikonin from roots of Lithospermum erythrorhizori, resveratrol dimer trans-ε-viniferin and tetramer r-2-viniferin), red wine extracts, or targeted synthetic small molecule (CaCC inh -A01) proved to be significantly effective in attenuating intestinal fluid secretion without affecting rotaviral infection (Figure 4b) [220][221][222][223][224].…”

Phytochemistry and Pharmacological Activities of Plumbago indica L.: An Overview

“…Plumbagin produces inhibition in smooth muscle contractility and delayed in intestinal motility and; inhibits both cAMP-activated and Ca 2+ Cl-channels as per mechanism and can be used in the therapy of CT-induced, rotaviral diarrhea and travelers with the inhibition of CaCC-calcium-activated Cl-channels and cystic fibrosis Transmembrane conductance regulator in both HT-29 cells and mouse colon. 40…”