TAB1 regulates glycolysis and activation of macrophages in diabetic nephropathy.

OBJECTIVE AND

DESIGN

Macrophages exhibit strong phenotypic plasticity and can mediate renal inflammation by polarizing into an M1 phenotype. They play a pivotal role in diabetic nephropathy (DN). Here, we have investigated the regulatory role of transforming growth factor β-activated kinase 1-binding protein 1 (TAB1) in glycolysis and activation of macrophages during DN.

METHODS

TAB1 was inhibited using siRNA in high glucose (HG)-stimulated bone marrow-derived macrophages (BMMs) and lentiviral vector-mediated TAB1 knockdown was used in streptozotocin (STZ)-induced diabetic mice. Western blotting, flow cytometry, qRT-PCR, ELISA, PAS staining and immunohistochemical staining were used for assessment of TAB1/nuclear factor-κB (NF-κB)/hypoxia-inducible factor-1α (HIF-1α), iNOS, glycolysis, inflammation and the clinical and pathological manifestations of diabetic nephropathy.

RESULTS

We found that TAB1/NF-κB/HIF-1α, iNOS and glycolysis were up-regulated in BMMs under HG conditions, leading to release of further inflammatory factors, Downregulation of TAB1 could inhibit glycolysis/polarization of macrophages and inflammation in vivo and in vitro. Furthermore, albuminuria, the tubulointerstitial damage index and glomerular mesangial expansion index of STZ-induced diabetic nephropathy mice were decreased by TAB1 knockdown.

CONCLUSIONS

Our results suggest that the TAB1/NF-κB/HIF-1α signaling pathway regulates glycolysis and activation of macrophages in DN.