Antioxidative properties of paraoxonase 2 in intestinal epithelial cells

Abstract

Paraoxonase (PON) family members seem central to a wide variety of human illnesses, but appreciation of their antioxidative function in the gastrointestinal tract is in its infancy. The major objective of the present work is to highlight the role of the ubiquitously expressed PON2 in the small intestine. With use of pLKO lentiviral vector containing short hairpin RNA (shRNA) lentivirus, PON2 expression was knocked down in intestinal Caco-2/15 cells, where antioxidative status, lipid peroxidation, and degree of inflammation were evaluated. As a consequence of PON2 inactivation in the epithelial cells, we observed 1) imbalanced primary and secondary antioxidative responses, characterized by increased superoxide dismutases and decreased catalase, 2) high concentrations of H2O2 and malondialdehyde, along with low glutathione-to-glutathione disulfide ratio, 3) upregulation of TNF-α, IL-6, and monocyte chemoattractant protein-1 gene expression after induction of oxidative stress, and 4) raised level of the activation of transcription factor NF-κB, which was likely implicated in exacerbation of the inflammatory activation. These results suggest that PON2 is involved in the antioxidative and anti-inflammatory response in intestinal epithelial cells.

Iron-Ascorbate-Mediated Lipid Peroxidation Causes Epigenetic Changes in the Antioxidant Defense in Intestinal Epithelial Cells: Impact on Inflammation

“…We have extensively used iron/ascorbate as a strong oxygen-radical generating system in our previous studies. To provide only few examples, we could document the ability of these combined molecules to (i) initiate sturdy lipid peroxidation in native cell membranes thereby affecting regulatory enzymes [63]; (ii) disturb the assembly and secretion of lipoproteins, thereby resulting in abnormal lipid transport [61], [64]; (iii) provoke inflammatory reactions in intestinal cells [65]; (iv) induce various dysregulations [24]–[26], [66]; and (v) produce harmful effects on mitochondrial function and DNA integrity [27]. Before performing many of these studies, we examined the impact of Fe/Asc on lipid peroxidation as a function of concentration and incubation periods [65].…”

“…Before performing many of these studies, we examined the impact of Fe/Asc on lipid peroxidation as a function of concentration and incubation periods [65]. In addition, relevant studies from our laboratory demonstrated that a 6 h-period is sufficient to induce inflammation by Fe/Asc [26], [27], [52]. The deteriorations resulting from the exposure of Caco-2/15 cells to Fe/Asc are probably attributable to OxS, because the addition of the Trolox antioxidant simultaneously alleviated, without totally preventing, the occurrence of lipid peroxidation along with inflammation relief.…”

“…Lipid peroxidation was estimated by measuring the release of free malondialdehyde (MDA) from Caco-2/15 cells in the culture medium by HPLC as described previously [24]–[26]. Proteins were first precipitated with a 10% sodium tungstate solution (Sigma).…”

“…The activities of SOD2, GPx and G-Red was measured as described previously [26]. Briefly, Caco-2/15 cells were harvested in hypotonic lysis buffer (10 mM HEPES, 1.5 mM MgCl 2 , 10 mM KCl, 0.5 mM DTT, and 0.2 mM PMSF).…”

Prevention of oxidative stress, inflammation and mitochondrial dysfunction in the intestine by different cranberry phenolic fractions

“…Intestinal Caco-2/15 cells were cultured as described previously [26][27][28][29][30][31][32][33][34]. Intestinal Caco-2/15 cells were cultured as described previously [26][27][28][29][30][31][32][33][34].…”