Abstract
Coeliac disease (CD) is a chronic, immune-mediated small intestinal enteropathy, accompanied with gluten-triggered oxidative damage of duodenal mucosa. Previously, our research group reported an increased mucosal level of the antioxidant protein Parkinson's disease 7 (PARK7) in children with CD. In the present study, we investigated the role of increased PARK7 level on the epithelial cell and mucosal integrity of the small intestine. The presence of PARK7 was investigated using immunofluorescent staining on duodenal mucosa of children with CD and on FHs74Int duodenal epithelial cells. To investigate the role of oxidative stress, FHs74Int cells were treated with H2O2 in the absence or presence of Comp23, a PARK7-binding compound. Intracellular accumulation of reactive oxygen species (ROS) was determined by DCFDA-based assay. Cell viability was measured by MTT, LDH, and Annexin V apoptosis assays. Disruption of cytoskeleton and cell adhesion was investigated by immunofluorescence staining and by real-time RT PCR. Effect of PARK7 on mucosal permeability was investigated ex vivo using intestinal sacs derived from control and Comp-23-pretreated mice. Comp23 treatment reduced the H2O2-induced intracellular accumulation of ROS, thus preserving the integrity of the cytoskeleton and also the viability of the FHs74Int cells. Accordingly, Comp23 treatment increased the expression of antioxidants (NRF2, TRX1, GCLC, HMOX1, NQO1), cell-cycle regulators (TP53, CDKN1A, PCNA, BCL2, BAX), and cell adhesion molecules (ZO1, CDH1, VCL, ITGB5) of H2O2-treated cells. Pretreatment with Comp23 considerably decreased the small intestinal permeability. In this study, we demonstrate that PARK7-binding Comp23 reduces the oxidative damage of duodenal epithelial cells, via increased expression of NRF2- and P53-regulated genes. Our results suggest that PARK7 plays a significant role in the maintenance of mucosal integrity in CD.
Highlights
Coeliac disease (CD) is a chronic, immune-mediated small intestinal enteropathy triggered by the ingestion of gluten in the genetically predisposed individuals [1]
An increased Parkinson’s disease 7 (PARK7) immunopositivity was observed in the epithelial cells of the duodenal crypt and in the lamina propria of duodenal biopsies derived from children with CD compared to controls (Figure 1(a))
The treatment with H2O2 resulted in an increasing accumulation of reactive oxygen species (ROS) in a dose-dependent manner, which was reduced by 0.001 μM Comp23 at each H2O2 concentration
Summary
Coeliac disease (CD) is a chronic, immune-mediated small intestinal enteropathy triggered by the ingestion of gluten in the genetically predisposed individuals [1]. PARK7 is suggested to exert antioxidative defence directly via its enzymatic and chaperon activity; PARK7 influences the degree of oxidative damage more likely through its transcriptional regulatory effect. In response to Oxidative Medicine and Cellular Longevity oxidative stress due to its conformation changes, PARK7 releases these transcription factors, allowing them to translocate into the nucleus and to induce the expression of stressresponse elements [11, 12]. These mechanisms altogether moderate the oxidative damage of intracellular macromolecules, promote repair processes, and enhance the viability of the affected cells
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