[Role of PKCδ on the phosphorylation and mitochondrial translocation of p66Shc in HK-2 cells induced by high glucose].

OBJECTIVE

To observe the effect of PKCδ on the phosphorylation of p66Shc and its mitochondrial translocation in human proximal tubular cells (HK-2) under high glucose (HG).

METHODS

HK-2 cells were incubated with different concentrations of D-glucose (5-45 mmol/L) for indicated time (0-48 h). Then the mRNA expressions of PKCδ and p66Shc and the phosphorylation levels of PKCδ (p-PKCδ) and p66Shc (p-p66Shc) were determined by real-time polymerase chain reaction (PCR) and Western blot analysis respectively. In addition, the effect of PKCδ inhibitor on the phosphorylation and mitochondrial translocation of p66Shc in HK-2 cells exposed to HG was also observed. HK-2 cells were divided into 3 groups of 5 mmol/L glucose, 30 mmol/L glucose and 30 mmol/L glucose + 1.0 µmol/L Rottlerin. Cell immunofluorescence and Western blotting were used to observe the phosphorylation and mitochondrial translocation of p66Shc.

RESULTS

Both mRNA expression and phosphorylation level of p66shc and PKCδ significantly increased in HK-2 cells after exposure to HG (15, 30, 45 mmol/L). And it was in a concentration- and time-dependent manner as compared with control group (up-regulated 0.9, 1.3 and 1.6-fold in mRNA of PKCδ, 0.4, 1.5 and 2.0-fold in protein of p-PKCδ respectively (all P < 0.05). PKCδ inhibitor Rottlerin dramatically inhibited the phosphorylation and mitochondrial translocation of p66Shc induced by HG in HK-2 cells (down-regulated 3.1 folds in protein of p-p66Shc in mitochondria, P < 0.01).

CONCLUSIONS

HG increases the transcription and phosphorylation of PKCδ and p66Shc in HK-2 cells. And PKCδ may modulate the phosphorylation and mitochondrial translocation of p66Shc under HG.