SUMOylation and deacetylation affect NF-κB p65 activity induced by high glucose in human lens epithelial cells.

Aim: To explore the effects of IκBα SUMOylation and NF-κB p65 deacetylation on NF-κB p65 activity induced by high glucose in cultured human lens epithelial cells (HLECs).

Methods: HLECs (SRA01/04) were cultured with 5.5, 25, and 50 mmol/L glucose media for 24h, and with 50 mmol/L glucose media for 0, 12, and 24h respectively. SUMO1 and SIRT1 expressions were detected by reverse transcription-polymerase chain reaction (RT-PCR) and Western blot (WB). IκBα and NF-κB p65 expressions were detected by WB. With NAC, DTT, MG132 or Resveratrol (RSV) treatment, SUMO1 and SIRT1 expressions were detected by WB. Protein expression localizations were examined by immunofluorescence and co-immunofluorescence. The effects of SUMO1 or SIRT1 overexpression, as well as MG132 and RSV, on the nuclear expression and activity of IκBα and NF-κB p65 were analyzed by immunoblot and dual luciferase reporter gene assay.

Results: SUMO1 and SIRT1 expressions were influenced by high glucose in mRNA and protein levels, which could be blocked by NAC or DTT. SUMO1 was down-regulated by using MG132, and SIRT1 was up-regulated under RSV treatment. IκBα nuclear expression was attenuated and NF-κB p65 was opposite under high glucose, while IκBα and NF-κB p65 location was transferred to the nucleus. SUMO1 or SIRT1 overexpression and MG132 or RSV treatment affected the nuclear expression and activity of IκBα and NF-κB p65 under high glucose condition.

Conclusion: IκBα SUMOylation and NF-κB p65 deacetylation affect NF-κB p65 activity in cultured HLECs under high glucose, and presumably play a significant role in controlling diabetic cataract.