Reductively modified albumin attenuates DSS-Induced mouse colitis through rebalancing systemic redox state

Abstract

Albumin (Alb) is the most abundant plasma protein with multiple biological functions, including antioxidative property through its thiol activity. Given that inflammatory bowel disease is associated with a decreased level of Alb and an increased level of Alb oxidation, we asked whether Alb could have a therapeutic effect on colitis. Here we tested this possibility. Bovine serum albumin (BSA) was reductively modified with dithiothreitol (DTT) and administrated via gavage or intraperitoneal injection. Dextran sulfate sodium (DSS)-induced mice colitis was associated with massive oxidative stress, as indicated by the elevated sulfenic acid formation in blood, colon tissues, and feces. Treatment of mice with the reductively modified albumin (r-Alb) attenuated the oxidative stress and reduced local inflammation and tissue injury. These effects of r-Alb were only partially achieved by unmodified Alb and wholly lost after blocking the –SH groups with maleimide. In cultured colon epithelial cells, r-Alb prevented DSS- and H 2 O 2 -induced ROS elevation and barrier dysfunction, preceded by inhibition of sulfenic acid formation and P38 activation. Further analysis revealed that Alb was susceptible to H 2 O 2 -induced oxidation, and it detoxified H 2 O 2 in a –SH group-dependent way. Moreover, Alb reacted with GSH/GSSG via thiol-disulfide exchange and reciprocally regulated the availability of –SH groups. Collectively, our study shows that r-Alb effectively attenuates DSS colitis via –SH group-mediated antioxidative action. Given that the oxidative stress underlies many life-threatening diseases, r-Alb, functioning as a potent antioxidant, could have a wide range of applications.

Tanshinone IIA Stimulates Cystathionine γ-Lyase Expression and Protects Endothelial Cells from Oxidative Injury

“…This assay was performed as we previously reported [31,33]. Cell lysates were extracted and allowed to react with Alexa Fluor 680 C2 maleimide (red fluorescence at the final concentration of 2.5 µM) at 4 • C for 2 h. Afterward, samples were separated by 10% SDS-PAGE and transferred to PVDF membranes.…”

“…Detection of sulfenic acid formation in protein samples was performed using an anti-cysteine sulfenic acid antibody from Millipore (Cat. #07-2139) as we had previously described [33]. Cells at 12-well plate were lysed at 100 µL dimedone lysis buffer (1 mM dimedone, 0.1%TX100, 0.012M Na 2 HPO 4 /0.003M Citric acid, PH6) for 20 min at RT, which was followed by the addition of 25 µL 5 X non-reducing sample buffer that contained 500 µM maleimide.…”

“…•− ) and ROS were detected using a kit from Enzo life sciences (Tokyo, Japan, ENZ-51010) following the protocol provided by the manufacturer [32,33,35]. Briefly, cells in 96-well plates were preloaded with O 2…”

“…Cells were allowed to incubate with a mixture of Calcein-AM (green) and PI (red) solution for 10-20 min. The PI-positive red and calcein-AM positive green cells were photographed using fluorescence microscopy [33,35].…”

ROS-responsive nanoparticles for oral delivery of luteolin and targeted therapy of ulcerative colitis by regulating pathological microenvironment

“…Reactive oxygen species (ROS) have been recognized as a common mechanism in UC [ 13 , 14 ]. Either antioxidants or free radical scavengers are reported as an effective therapeutic agent for UC [ 15 , 16 ]. Moreover, due to the relatively high ROS concentration in UC tissue, ROS responsive system may specifically release drugs in inflamed colon tissues [ 13 ].…”