ChREBP Deficiency Suppresses Renal Inflammation and Fibrosis Via Inhibiting NLRP3 Inflammasome Activation in Diabetic Kidney Disease.

BACKGROUND AND AIM: Diabetic kidney disease (DKD) is the most-common cause of chronic renal failure and end-stage renal disease (ERSD) in diabetes mellitus (DM) patients. Renal inflammation and glomerular or interstitial fibrosis are mainly associated with the progression of DKD. Carbohydrate response element binding protein (ChREBP) is activated and transcribed in a glucose dependent manner. This study is aimed at exploring the role and underlying mechanisms of ChREBP in DKD. METHODS: ChREBP knockout mice, obtained by CRISPR Cas9 gene editing technology, were used to study the effects of ChREBP on inflammation and fibrosis in diabetic kidney of mice. Human renal tubular epithelial (HK-2) cells were cultured in a medium containing normal or high glucose levels. Additionally, the role of ChREBP in high glucose (HG)-induced NLRP3 inflammasome activation was assessed. RESULTS: We identified that renal inflammation, renal extracellular matrix deposition, and renal fibrosis were restored by ChREBP deficiency in diabetic mouse kidney. Consequently, ChREBP deficiency decreased the activation of nucleotide leukin-rich polypeptide 3 (NLRP3) inflammasome, which later restrained hyperglycemia-induced renal fibrosis. Importantly, NLRP3 inflammasome aggravated the above-mentioned renal fibrosis via TGF-ß1 expression and the signaling pathways of Smad2/3 and the p38 MAPK. Additionally, ChREBP deficiency inhibited NLRP3 inflammasome activation both in HG-induced HK-2 cells and diabetic mouse kidney. CONCLUSION: Our findings establish a critical role of ChREBP in engaging inflammation and renal fibrosis by regulating NLRP3 inflammasome activation in DKD.

ChREBP deficiency alleviates apoptosis by inhibiting TXNIP/oxidative stress in diabetic nephropathy.

AIMS: In the present study, we investigated the effect of carbohydrate responsive element binding protein (ChREBP) on the TXNIP/oxidative stress and apoptosis in diabetic nephropathy. METHODS: ChREBP-/- mice (8-week old) were produced using the CRISPR/Cas9 gene editing approach. Diabetes was induced in C57BL/6 mice with streptozotocin. HK-2 cells was transfected with plasmid containing either ChREBP shRNA or TXNIP siRNA. RESULTS: Renal expression of ChREBP and thioredoxin-interacting protein (TXNIP) was increased in patients with type 2 diabetes mellitus (T2DM) and diabetic mice. ChREBP deficiency improved renal function, apoptosis as well as endoplasmic reticulum (ER) stress in diabetic mice. In addition, ChREBP deficiency prevented expression levels of TXNIP and NADPH oxidase 4 (Nox4), 8-hydroxydeoxyguanosine (8-OHdG) and heme oxygenase-1 (HO-1) in diabetic kidneys. The increased urinary 8-OHdG level induced by diabetes was also attenuated in ChREBP deficiency mice. Similarly, HG was shown to induce ChREBP expression and nuclear translocation in HK-2 cells. HG-induced apoptosis was inhibited by transfection of ChREBP shRNA plasmid. Moreover, we found that knockdown of ChREBP suppressed HG-induced TXNIP and Nox4 expression, reactive oxygen species (ROS) generation and ER stress in HK-2 cells. Furthermore, TXNIP knockdown effectively abrogated HG-induced apoptosis in HK-2 cells. CONCLUSIONS: These results suggest that ChREBP deficiency prevents diabetes-induced apoptosis via inhibiting oxidative stress and ER stress, highlighting ChREBP as a potential therapy target for diabetic nephropathy.