Poly(ADP-ribose) polymerase-1 gene ablation protects mice from ischemic renal injury

Abstract

Increased generation of reactive oxygen species (ROS) and the subsequent DNA damage and excessive activation of poly(ADP-ribose) polymerase-1 (PARP-1) have been implicated in the pathogenesis of ischemic injury. We previously demonstrated that pharmacological inhibition of PARP protects against ischemic renal injury (IRI) in rats (Martin DR, Lewington AJ, Hammerman MR, and Padanilam BJ. Am J Physiol Regul Integr Comp Physiol 279: R1834-R1840, 2000). To further define the role of PARP-1 in IRI, we tested whether genetic ablation of PARP-1 attenuates tissue injury after renal ischemia. Twenty-four hours after reperfusion following 37 min of bilateral renal pedicle occlusion, the effects of the injury on renal functions in PARP-/- and PARP+/+ mice were assessed by determining glomerular filtration rate (GFR) and the plasma levels of creatinine. The levels of plasma creatinine were decreased and GFR was augmented in PARP-/- mice. Morphological evaluation of the kidney tissues showed that the extent of damage due to the injury in PARP-/- mice was less compared with their wild-type counterparts. The levels of ROS and DNA damage were comparable in the injured kidneys of PARP+/+ and PARP-/- mice. PARP activity was induced in ischemic kidneys of PARP+/+ mice at 6-24 h postinjury. At 6, 12, and 24 h after injury, ATP levels in the PARP+/+ mice kidney declined to 28, 26, and 43%, respectively, whereas it was preserved close to normal levels in PARP-/- mice. The inflammatory cascade was attenuated in PARP-/- mice as evidenced by decreased neutrophil infiltration and attenuated expression of inflammatory molecules such as TNF-alpha, IL-1beta, and intercellular adhesion molecule-1. At 12 h postinjury, no apoptotic cell death was observed in PARP-/- mice kidneys. However, by 24 h postinjury, a comparable number of cells underwent apoptosis in both PARP-/- and PARP+/+ mice kidneys. Thus activation of PARP post-IRI contributes to cell death most likely by ATP depletion and augmentation of the inflammatory cascade in the mouse model. PARP ablation preserved ATP levels, renal functions, and attenuated inflammatory response in the setting of IRI in the mouse model. PARP inhibition may have clinical efficacy in preventing the progression of acute renal failure complications.

Peritubular Ischemia Contributes More to Tubular Damage than Proteinuria in Immune-Mediated Glomerulonephritis

“…Other possible mechanisms associated with initial FcR activation by anti-GBM antibody, such as acute cytokine activation or production of reactive oxygen species in glomeruli and subsequent tubular damage, 27,28 could play an additional role.…”

Targeted Deletion of p53 in the Proximal Tubule Prevents Ischemic Renal Injury

“…31,44 All animals were given free access to food and water. The mice were anesthetized by intraperitoneal administration of a cocktail containing ketamine (200 mg) and xylazine (16 mg) per 1 kg body wt.…”

“…44 The slides were sequentially incubated with rabbit anti-mouse neutrophil antibody (Accurate, Westbury, NY) at a 1:100 dilution overnight at 4°C followed by FITCconjugated goat anti-rabbit IgG (Vector Laboratories, Burlingame, CA) at a 1:200 dilution for 1 hour at room temperature. Neutrophil infiltration was quantified by counting the number of stained cells per field.…”

“…44 The slides were sequentially incubated with mouse anti-a-SMA antibody (A5228; Sigma-Aldrich) at a 1:500 dilution overnight at 4°C followed by FITC-conjugated horse anti-mouse IgG (Vector Laboratories) at a 1:200 dilution for 1 hour at room temperature. a-SMA deposition was quantified by measuring a-SMA-positive area per field.…”

Mice Lacking the 110-kD Isoform of Poly(ADP-Ribose) Glycohydrolase Are Protected against Renal Ischemia/Reperfusion Injury

“…Although both isoforms exhibit exo-and endoglycosidase activity, PARG 110 is the major form of PARG in the nucleus (6,7) Inhibitors of PARP activity reduce the tissue injury caused by I/R of the heart (8,9), brain (10), gut (11), liver (12), and kidney (13). Most notable, the degree of tissue injury caused by I/R in the heart (14), brain (15), gut (16), and most recently kidney (17) is reduced in mice in which the gene encoding for PARP-1 has been disrupted (PARP-1 Ϫ/Ϫ mice). These studies support the view that the excessive activation of PARP-1 plays a key role in the pathophysiology of I/R injury.…”