Indomethacin-induced translocation of bacteria across enteric epithelia is reactive oxygen species-dependent and reduced by vitamin C

Abstract

Schoultz I, McKay CM, Graepel R, Phan VC, Wang A, Söderholm J, McKay DM. Indomethacin-induced translocation of bacteria across enteric epithelia is reactive oxygen species-dependent and reduced by vitamin C. Am J Physiol Gastrointest Liver Physiol 303: G536-G545, 2012. First published June 14, 2012 doi:10.1152/ajpgi.00125.2012.-The enteric epithelium must absorb nutrients and water and act as a barrier to the entry of luminal material into the body; this barrier function is a key component of innate immunity. Nonsteroidal anti-inflammatory drug (NSAID)-induced enteropathy occurs via inhibition of prostaglandin synthesis and perturbed epithelial mitochondrial activity. Here, the direct effect of NSAIDs [indomethacin, piroxicam (cyclooxygenase 1 and 2 inhibitors), and SC-560 (a cyclooxygenase 1 inhibitor)] on the barrier function of human T84 epithelial cell line monolayers was assessed by transepithelial electrical resistance (TER) and internalization and translocation of a commensal Escherichia coli. Exposure to E. coli in the presence and absence of drugs for 16 h reduced TER; however, monolayers cotreated with E. coli and indomethacin, but not piroxicam or SC-560, displayed significant increases in internalization and translocation of the bacteria. This was accompanied by increased reactive oxygen species (ROS) production, which was also increased in epithelia treated with E. coli only. Colocalization revealed upregulation of superoxide synthesis by mitochondria in epithelia treated with E. coli ϩ indomethacin. Addition of antioxidants (vitamin C or a green tea polyphenol, epigallocathechin gallate) quenched the ROS and prevented the increase in E. coli internalization and translocation evoked by indomethacin, but not the drop in TER. Evidence of increased apoptosis was not observed in this model. The data implicate epithelial-derived ROS in indomethacin-induced barrier dysfunction and show that a portion of the bacteria likely cross the epithelium via a transcellular pathway. We speculate that addition of antioxidants as dietary supplements to NSAID treatment regimens would reduce the magnitude of decreased barrier function, specifically the transepithelial passage of bacteria. permeability; nonsteroidal anti-inflammatory drug; mitochondria; intestine

ER-stress mobilization of death-associated protein kinase-1–dependent xenophagy counteracts mitochondria stress–induced epithelial barrier dysfunction

“…Fig.1D). ] The NSAID indomethacin increased intracellular viable E. coli in T84 cells (9) and this was reduced by tunicamycin ( Fig.1E) [HeLa cells provided similar data (Suppl. Fig.2 (Fig.1F).…”

“…For instance, NSAID use can elicit disease relapse in some patients with IBD (29), and NSAID enteropathy is characterized by abnormal epithelial mitochondrial structure (8,9). Modelling mitochondria dysfunction with DNP treatment provided evidence that targeted loss of mitochondria function resulted in ROSdependent internalization of bacteria by enteric epithelia (15).…”

“…For instance, nonsteroidal anti-inflammatory drugs (NSAID) can cause relapses in IBD (7) and their use damages mitochondria contributing to decreased enteric barrier function (8,9).…”

The relationship between vitamin C status, the gut-liver axis, and metabolic syndrome

“…This proposed mechanism is consistent with ascorbate's coenzyme function that hydroxylates proline and lysine to cross-link collagen [85]. For example, studies in the T84 human crypt-like epithelial cell line with indomethacin-induced barrier dysfunction show that bacteria cross the epithelium via a transcellular pathway, which is abrogated by treatment with vitamin C [74]. Thus, poor ascorbate status at the gut likely exacerbates barrier dysfunction that increases the translocation of LPS-derived Gram-negative bacteria to potentiate inflammation.…”

“…C-reactive protein, procalcitonin) [71], thereby demonstrating the close interrelationship of inadequate vitamin C status, endotoxemia, and increased inflammation. In agreement, vitamin C supplementation reverses these effects in vitro [74], in translational models [62], [75], [76], [77], and in humans [71], [72].…”