Box A of HMGB1 Maintains the DNA Gap and Prevents DDR-induced Kidney Injury in D-galactose Induction Rats

Abstract

Background/Aim: Disability and mortality rates for renal failure are still increasing. DNA damage and oxidative stress intoxication from body metabolism, high blood glucose, or the environment cause significant kidney damage. Recently, we reported that Box A of HMGB1 (Box A) acts as molecular scissors, producing DNA gaps that prevent DNA damage in kidney cell lines and ultimately reverse aging phenotypes in aging rat models. The present study aimed to demonstrate the potency of Box A in preventing D-galactose (D-gal)-induced kidney injury. Materials and Methods: A Box A expression plasmid was constructed and administered to a rat model. D-gal was injected subcutaneously for eight weeks. Serum was collected to study renal function, and white blood cells were collected for DNA gap measurement. Kidney tissue was also collected for γ-H2AX and NF-ĸB immunostaining; Senescence-associated (SA)-beta-gal staining; and analysis of the mRNA expression of p16 INK4A , TNF-α, and IL-6. Moreover, histopathology analysis was performed using hematoxylin & eosin and Masson trichome staining. Results: Pretreatment with Box A administration prevented the reduction of DNA gaps and the consequences of the DNA damage response, which include elevated serum creatinine; high serum BUN; an increased positive SA-beta-gal staining area; overexpression of p16 INK4A , NF-ĸB and senescenceassociated secretory phenotype molecules, including IL-6, TNF-α; and histological alterations, including tubular dilation and collagen accumulation. Conclusion: Box A effectively prevents DNA gap reduction and all D-gal-induced kidney pathological changes at the molecular, histological, and physiological levels. Therefore, Box A administration is a promising novel therapeutic strategy to prevent DNAdamaging agent-induced kidney failure.DNA damage and the associated DNA damage response (DDR) have been identified as common causes of kidney injury. Chemicals, ischemia-reperfusion injury, or sepsis can cause DNA damage with increased apoptosis of renal tubular epithelial cells, interstitial fibrosis, and ultimately chronic kidney disease (CKD) (1). Diabetes is a critical and commonly leading cause of CKD that accounts for nearly 50% of the 1170