Abstract
Background and Aims
Diabetic kidney disease (DKD) is the major cause of end-stage kidney disease which is characterized by prominent kidney fibrosis. Src family kinases (SFKs), a family of proto-oncogenes, has been acknowledged to mediate the development of kidney fibrosis. While, several studies in liver and skeletal muscle suggested the role of Src kinases in activating endoplasmic reticulum (ER) stress. The present study aimed to investigate the mechanism of Src kinases-ER stress in mediating the progression of DKD.
Method
Type 1 diabetes was induced by a single 60 mg/kg i.p injection of streptozotocin (STZ) in 7-week-old male, Sprague-Dawley rats. Diabetic rats received 8-week-treatment of either KF-1607 (30 mg/kg/day), a pharmacological inhibitor of SFKs, or losartan (1 mg/kg/day), a standard treatment for patients with DKD.
Results
Among SFKs, Fyn and Lyn kinases were particularly increased in the diabetic kidney. Inhibition of Src kinases by KF-1607 improved kidney function and inhibited tubular injury, presented by decreased serum creatinine, albuminuria, and urinary KIM-1 excretion. Pathological changes in the kidney, such as enhanced glomerular volume, tuft area, and fractional mesangial area, were ameliorated in KF-treated rats. Highly-accumulated collagen network as well as increased TGF-β and α-SMA mRNA levels in the diabetic kidney were also significantly reduced in response to KF treatment. Furthermore, it consistently attenuated kidney inflammation and oxidative stress. The renoprotective effects of KF were interestingly similar to those of losartan. We showed increases in protein levels of phosphorylated IRE-1α, ATF6, GRP78 as well as CHOP indicating an exacerbated ER stress in the diabetic kidney. These ER stress markers were significantly decreased in KF treated mice.
Conclusion
Altogether, Src kinases through activation of ER stress aggravates kidney injury in STZ-induced diabetic rats.
Do Tubular Changes in the Diabetic Kidney Affect the Susceptibility to Acute Kidney Injury?
