[Expressions of reactive oxygen species and fibronectin are regulated by transcriptional co-activator p300 in human mesangial cells exposed to high glucose and methylglyoxal advanced glycation end products].

OBJECTIVE

To study the roles and interrelationship of transcriptional co-activator p300 and protein kinase Cβ2(PKCβ2) in the production of reactive oxygen species (ROS) and the expression of fibronectin in human mesangial cells (HMCs) under the stimulation of high glucose and methylglyoxal-derived advanced glycation end products (AGEs).

METHODS

The HMCs were divided into the following groups: 1 normal glucose group (NG), high glucose group (HG), osmotic control group (LG), normal glucose+bovine serum albumin group (BSA), normal glucose+AGEs group (AGEs); 2 high glucose+empty vector group (HN), high glucose+PKCβ2 group (PO), high glucose+PKCβ2 inhibitor CGP53353 group (PI), AGEs+empty vector group (AN), AGEs+PKCβ2 group (APO), AGEs+PKCβ2 inhibitor CGP53353 group (API); 3 normal glucose+p300 inhibitor garcinol group (NG+Gar), high glucose+garcinol group (HG+Gar), BSA+garcinol group (BSA+Gar), and AGEs+garcinol group (AGEs+Gar). All cells in each group were cultured for 2 d. ROS levels were measured by fluorescence microscope and fluorescence microplate reader. The protein expressions of p300, PKCβ2 and fibronectin were detected by Western blotting.

RESULTS

Levels of p300, PKCβ2 and ROS in HG and AGEs groups were elevated by 1.04, 1.26, 0.78 and 1.45, 1.07, 0.71 folds of those in NG group and BSA control group, respectively (P<0.05). However, ROS levels in HG+Gar and AGEs+Gar groups decreased significantly to 0.43 and 0.39 folds of those in HG and AGEs groups, respectively (P<0.05). p300 and PKCβ2 protein expressions in PO and APO groups were up-regulated by 1.19, 1.73 and 1.23, 1.69 folds compared with HG and AGEs groups, respectively (P<0.05). However, in the present of CGP53353, both p300 and PKCβ2 decreased significantly (P<0.05); the two factors stayed stable in HN and AN groups as compared with HG and AGEs groups. Expressions of p300 and FN proteins decreased in HG+Gar and AGEs+Gar groups, being 31%, 43% and 37%, 29% of those in HG and AGEs groups, respectively (P<0.05).

CONCLUSION

High glucose and AGEs can up-regulate the expressions of ROS and fibronectin in human mesangial cells by activating transcriptional co-activator p300.