Diabetes-induced activation of canonical and noncanonical nuclear factor-kappaB pathways in renal cortex

Area of Science:

• Nephrology
• Molecular Biology
• Endocrinology

Background:

• Diabetes mellitus is associated with kidney complications.
• Nuclear factor-kappaB (NF-kappaB) activation is implicated in diabetic kidney disease.
• Mechanisms of NF-kappaB activation in diabetes remain incompletely understood.

Purpose of the Study:

• To investigate the effects of diabetes on NF-kappaB canonical and noncanonical activation pathways in the renal cortex.
• To elucidate the specific proteins and cellular locations involved in NF-kappaB activation during diabetes.

Main Methods:

• Utilized diabetic (db/db) mice model.
• Analyzed renal cortex protein expression and localization via immunohistochemistry.
• Assessed protein phosphorylation and nuclear translocation.
• Quantified NF-kappaB DNA binding activity using electrophoretic mobility shift assay (EMSA).

Main Results:

• Elevated plasma cytokines during early diabetes normalized, but renal cortex cytokine levels remained high.
• NF-kappaB noncanonical pathway proteins, including IKK-alpha, NIK, and RelB, were significantly increased in tubular epithelial cells.
• Despite decreased nuclear content of NF-kappaB proteins, EMSA confirmed increased DNA binding activity in diabetic kidneys.
• NF-kappaB canonical pathway proteins showed no significant changes in cytosolic content.

Conclusions:

• Diabetes induces chronic NF-kappaB activation in the renal cortex of db/db mice.
• A novel diabetes-linked mechanism involving both canonical and noncanonical NF-kappaB pathways is suggested.
• Specific alterations in noncanonical pathway proteins and their localization highlight a key aspect of diabetic nephropathy.