Poly (ADP-ribose) polymerase as a potential target for the treatment of acute renal injury caused by lipopolysaccharide

Effect of curcumin on methotrexate-induced ovarian damage and follicle reserve in rats: the role of PARP-1 and P53

BACKGROUND

Methotrexate (MTX) is an agent used in the treatment of many neoplastic and non-neoplastic diseases and is known to cause oxidative damage in normal tissues. Curcumin (Cur) is a natural polyphenol compound with powerful antioxidant and antiapoptotic effects. In this study we investigate the effects of Cur on MTX-induced ovarian damage.

MATERIALS AND METHODS

Thirty-two young adult female Wistar albino rats were divided into four groups: (1) Control (n = 8): only vehicle group, (2) Cur (n = 8): Cur-only group (200 mg/kg/day), (3) MTX (n = 8): MTX-only group (0.35 mg/kg/day), (4) MTX+Cur (n = 8): The group was given MTX (0.35 mg/kg/day) and Cur (200 mg/kg/day) for 28 days. Then, SOD, CAT, MDA, AMH levels were measured using ELISA kits. Follicle count was performed on H&E stained slides. In addition, the expressions of P53 and PARP-1 were analysed by immunohistochemistry.

RESULTS

MDA levels were seen to be higher in the MTX group than in the MTX+Cur group (p < 0.05). Cur treatment lowered MDA levels and increased SOD and CAT levels (p < 0.05 for all). In the MTX+Cur group, atretic follicle count decreased (p < 0,05), however, primordial follicle count increased (p < 0,01). Secondary follicle count and AMH levels were higher in MTX-treated groups (p < 0,05 and p < 0,01, respectively). Expressions of p53 and Poly [ADP-ribose] polymerase 1 (PARP-1) increased significantly in the MTX group compared to the other groups (p < 0,05).

CONCLUSION

Cur pretreatment prior to MTX administration may be an effective option in preserving the ovarian follicle pool by regulating P53 and PARP-1 expressions with its antioxidant effect.

An Overview of Pathways of Regulated Necrosis in Acute Kidney Injury

Necrosis is the predominant form of regulated cell death in acute kidney injury (AKI) and represents results in the formation of casts that appear in the urine sedimentation, referred to as muddy brown casts, which are part of the diagnosis of AKI. Pathologists referred to this typical feature as acute tubular necrosis. We are only beginning to understand the dynamics and the molecular pathways that underlie such typical necrotic morphology. In this review, we provide an overview of candidate pathways and summarize the emerging evidence for the relative contribution of these pathways of regulated necrosis, such as necroptosis, ferroptosis, mitochondrial permeability transition-mediated regulated necrosis, parthanatos, and pyroptosis. Inhibitors of each of these pathways are available, and clinical trials may be started after the detection of the most promising drug targets, which will be discussed here. With the global burden of AKI in mind, inhibitiors of regulated necrosis represent promising means to prevent this disease.

PARP inhibitor, olaparib ameliorates acute lung and kidney injury upon intratracheal administration of LPS in mice

We have previously shown that PARP-1 inhibition provides protection against lung inflammation in the context of asthma and acute lung injury. Olaparib is a potent new generation PARP inhibitor that has been approved for human testing. The present work was designed to evaluate its beneficial potential against LPS-induced acute lung injury and acute kidney injury upon intratracheal administration of the endotoxin in mice. Administration of olaparib at different doses, 30 min after LPS treatment showed that single intraperitoneal injection of the drug at 5 mg/kg b.wt. reduced the total number of inflammatory cells particularly neutrophils in the lungs. This was associated with reduced pulmonary edema as the total protein content in the bronchoalveolar fluid was found to be decreased substantially. Olaparib provided strong protection against LPS-mediated secondary kidney injury as reflected by restoration of serum levels of urea, creatinine, and uric acid toward normal. The drug restored the LPS-mediated redox imbalance toward normal in lung and kidney tissues as assessed by measuring malondialdehyde and GSH levels. Finally, RT-PCR data revealed that olaparib downregulates the LPS-induced expression of NF-κB-dependent genes namely TNF-α, IL-1β, and VCAM-1 in the lungs without altering the expression of total p65NF-κB. Overall, the data suggest that olaparib has a strong potential to protect against LPS-induced lung injury and associated dysfunctioning of kidney in mice. Given the fact that olaparib is approved by FDA for human testing, our findings can pave the way for testing of the drug on humans inflicted with acute lung injury.

Role of poly (ADP-ribose)-polymerase and its signaling pathway with renin-angiotensin aldosterone system in renal diseases

Poly(ADP-ribose) polymerase (PARP), a ubiquitous, chromatin-bound enzyme, plays a crucial role in many processes, including DNA repair, cell death, metabolism, and inflammatory responses, by activating DNA repair pathways responsible for cellular survival. Renin-angiotensin-aldosterone system (RAAS) genes encode renin, angiotensinogen, angiotensin-converting enzyme, angiotensin type-1 receptor and aldosterone synthase gene. RAAS is a hormone system which acts on multiple physiologic pathways primarily by regulating blood pressure, electrolyte and fluid homeostasis in mammals, but also by local autocrine and paracrine actions. The current status quo of scientific evidence shows that there might be a signaling pathway between PARP and RAAS. Herein, we review the role of PARP and its signaling pathways with RAAS in renal diseases.

Therapeutic applications of PARP inhibitors: anticancer therapy and beyond

The aim of this article is to describe the current and potential clinical translation of pharmacological inhibitors of poly(ADP-ribose) polymerase (PARP) for the therapy of various diseases. The first section of the present review summarizes the available preclinical and clinical data with PARP inhibitors in various forms of cancer. In this context, the role of PARP in single-strand DNA break repair is relevant, leading to replication-associated lesions that cannot be repaired if homologous recombination repair (HRR) is defective, and the synthetic lethality of PARP inhibitors in HRR-defective cancer. HRR defects are classically associated with BRCA1 and 2 mutations associated with familial breast and ovarian cancer, but there may be many other causes of HRR defects. Thus, PARP inhibitors may be the drugs of choice for BRCA mutant breast and ovarian cancers, and extend beyond these tumors if appropriate biomarkers can be developed to identify HRR defects. Multiple lines of preclinical data demonstrate that PARP inhibition increases cytotoxicity and tumor growth delay in combination with temozolomide, topoisomerase inhibitors and ionizing radiation. Both single agent and combination clinical trials are underway. The final part of the first section of the present review summarizes the current status of the various PARP inhibitors that are in various stages of clinical development. The second section of the present review summarizes the role of PARP in selected non-oncologic indications. In a number of severe, acute diseases (such as stroke, neurotrauma, circulatory shock and acute myocardial infarction) the clinical translatability of PARP inhibition is supported by multiple lines of preclinical data, as well as observational data demonstrating PARP activation in human tissue samples. In these disease indications, PARP overactivation due to oxidative and nitrative stress drives cell necrosis and pro-inflammatory gene expression, which contributes to disease pathology. Accordingly, multiple lines of preclinical data indicate the efficacy of PARP inhibitors to preserve viable tissue and to down-regulate inflammatory responses. As the clinical trials with PARP inhibitors in various forms of cancer progress, it is hoped that a second line of clinical investigations, aimed at testing of PARP inhibitors for various non-oncologic indications, will be initiated, as well.

Inhibition of poly (adenosine diphosphate-ribose) polymerase attenuates lung-kidney crosstalk induced by intratracheal lipopolysaccharide instillation in rats

Background

Acute respiratory distress syndrome (ARDS) is a severe form of lung injury that frequently occurs during pneumonia and sepsis. Lung inflammation in ARDS patients may have deleterious effects on remote organs such as the kidney. The nuclear enzyme poly(adenosine diphosphate-ribose) polymerase (PARP) enhances the nuclear factor (NF)-κB-dependent transcription of inflammatory cytokines. This study was conducted to elucidate two questions: first, whether the activation of PARP and NF-κB mediates the renal inflammation secondary to the lipopolysaccharide (LPS)-induced acute lung inflammation; second, whether a PARP inhibitor, 3-aminobenzamide (3-AB), attenuates lung and kidney inflammation by inhibiting NF-κB-dependent proinflammatory cytokines.

Methods

Male Sprague–Dawley rats were anesthetized, ventilated, and divided into three groups; a control group (n = 8); an LPS group (n = 12) intratracheally instilled with LPS (16 mg/kg), and an LPS + 3-AB group (n = 12) given the same dose of LPS by the same method followed by an intravenous injection of 3-AB (20 mg/kg). Hemodynamics, arterial blood gas, and the plasma levels of lactate, creatinine and potassium were measured at 0,1,2,3, and 4 h after treatment. The lung wet/dry ratio was measured at 4 h. The mRNA expression of tumor necrosis factor (TNF)-α, interleukin (IL)-1β and IL-6 in the lung and kidney were measured by TaqMan real-time PCR. PARP and NF-κB in the lung and kidney were histologically examined by immunostaining and assigned expression scores.

Results

LPS induced metabolic acidosis, hypotension, hypoxemia, increased the lung wet/dry ratio, increased the plasma levels of creatinine and potassium, and increased the cytokine mRNA expressions in the lung and kidney. All of these effects were associated with strong expression of PARP and NF-κB. Treatment with 3-AB prevented the LPS-induced metabolic acidosis and hypotension, reduced the plasma levels of lactate, creatinine and potassium, reduced the cytokine mRNA expressions, reduced the expression of PARP and NF-κB, improved pulmonary edema and oxygenation and preserved renal function.

Conclusions

The PARP inhibition attenuated lung-kidney crosstalk induced by intratracheal LPS instillation, partly via an inhibition of NF-κB dependent proinflammatory cytokines.

Potential role of poly(ADP-ribose) polymerase (PARP) activation in methotrexate-induced nephrotoxicity and tubular apoptosis

Nephrotoxicity is one of the serious dose-limiting complications of methotrexate (MTX) when used in the treatment of various malignancies and nononcological diseases. The aim of this study was to investigate the role of poly(adenosine diphosphate ribose) polymerase (PARP) activity in MTX-induced nephrotoxicity. Rats were divided into 4 groups as control, MTX treated (MTX, 7 mg/kg per d, intraperitoneally [ip], once daily for 3 consecutive days), MTX plus 1,5-isoquinelinediol (ISO, a PARP inhibitor, 3 mg/kg per d, i.p.) treated, or ISO treated. Histopathology of kidneys was evaluated by light microscopy. Terminal deoxynucleotidyl transferase deoxyuridine triphosphate nick end labeling assay was used to analyze apoptosis in kidney sections. Blood urea nitrogen (BUN), serum creatinine, and urinary N-acetyl-β-d-glucosaminidase (NAG) were used as biochemical markers of MTX-induced renal injury. Our results showed that MTX administration significantly increased BUN, serum creatinine, and urinary NAG levels. The PARP-1 and PAR (a product of PARP activity) expression and apoptotic cell death were also markedly increased in renal tubules after MTX administration. The ISO treatment attenuated MTX-induced renal injury, as indicated by BUN and serum creatinine levels, urinary NAG excretion, and renal histology. The PARP inhibitor treatment reduced PARP-1 and PAR expression to levels similar to that of controls. These results revealed that ISO may have a protective effect against the nephrotoxic effects of MTX by inhibiting PARP activation. This is the first study that demonstrates the role of PARP activation in MTX-induced nephrotoxicity and tubular apoptosis.

Aminoguanidine, a selective nitric oxide synthase inhibitor, attenuates cyclophosphamide-induced renal damage by inhibiting protein nitration and poly(ADP-Ribose) polymerase activation

BACKGROUND

Cyclophosphamide (CP) is an antineoplastic agent that is used for the treatment of many neoplastic diseases. Renal damage is one of the dose-limiting side effects of CP. Recent studies show that nitrosative stress plays an important role in CP-induced renal damage.

AIM

The purpose of our study was to investigate whether aminoguanidine (AG), a selective inducible nitric oxide synthase inhibitor, protects against CP-induced nitrosative stress and renal damage.

METHOD

Renal damage was induced in rats by administration of a single injection of CP at a dose of 150 mg/kg body weight intraperitoneally. For the AG pretreatment studies, the rats were injected intraperitoneally with AG at a dose of 200 mg/kg body weight 1 h before administration of CP. The control rats received AG or saline alone. All the rats were killed 16 h after the administration of CP or saline. Pretreatment with AG prevented CP-induced nitration of protein tyrosine and poly(ADP-ribose) polymerase (PARP) activation.

RESULT

Pretreatment with AG attenuated CP-induced renal damage. The present study demonstrates that AG is effective in preventing CP-induced renal damage and also that the protective effect is from its ability to inhibit nitric oxide-induced protein nitration and PARP activation.

CONCLUSION

The present study shows that AG can prevent CP-induced renal damage by inhibiting protein tyrosine nitration and PARP activation. Thus, a more efficient and comfortable therapy can be achieved for patients in need of CP treatment. AG appears to be a promising drug for the prevention of nephrotoxicity of CP.

Role of the poly(ADP-ribose)polymerase activity in vancomycin-induced renal injury

The aim of the present study was to investigate the role of poly(ADP-ribose)polymerase (PARP) activity in vancomycin (VCM)-induced renal injury and to determine whether 1,5-isoquinelinediol (ISO), a PARP inhibitor agent, could be offered as an alternative therapy in VCM-induced renal impairment. Rats were divided into four groups as follows: (i) control (Group 1); (ii) VCM-treated (Group 2); (iii) VCM plus ISO-treated (Group 3); and (iv) ISO-treated (Group 4). VCM (200mg/kg, i.p., twice daily) was administered to Groups 2 and 3 for 7 days. ISO (3mg/kg/day, i.p.) treatment was started 24h before the first administration of VCM and continued for 8 days. After the 14th VCM injection, the animals were placed in metabolic cages to collect urine samples. All the rats were sacrificed by decapitation, blood samples were taken in tubes and kidneys were excised immediately. Blood urea nitrogen (BUN) and plasma creatinine, and urinary N-acetyl-beta-d-glucosaminidase (NAG, a marker of renal tubular injury) were used as markers of VCM-induced renal injury in rats. Light microscopy was used to evaluate semi-quantitative analysis of the kidney sections. Poly(ADP-ribose) (PAR, the product of activated PARP) and PARP-1 expressions in renal tissues were demonstrated by immunohistochemistry and Western blot. VCM administration increased BUN levels from 8.07+/-0.75 mg/dL to 53.87+/-10.11 mg/dL. The plasma creatinine levels were 0.8+/-0.04 mg/dL and 3.38+/-0.51 mg/dL for the control and VCM-treated groups, respectively. Also, urinary excretion of NAG was increased after VCM injection. Besides, there was a significant dilatation of the renal tubules, eosinophilic casts within some tubules, desquamation and vacuolization of renal tubule epithelium, and interstitial tissue inflammation in VCM-treated rats. In VCM-treated rats, both PAR and PARP-1 expressions were increased in renal tubular cells. ISO treatment attenuated VCM-induced renal injury, as indicated by BUN and plasma creatinine levels, urinary NAG excretion, and renal histology. PARP inhibitor treatment also decreased PAR and PARP-1 protein expressions similar to that of controls. Herewith, the overactivation of the PARP pathway may have a role in VCM-induced renal impairment and pharmacological inhibition of this pathway might be an effective intervention to prevent VCM-induced acute renal injury.

Aldosterone-induced endothelial dysfunction of rat aorta: role of poly(ADP-ribose) activation

Introduction. The aim of this study was to investigate whether activation of the nuclear enzyme poly(ADP-ribose) polymerase (PARP) contributes to the development of aldosterone-induced endothelial dysfunction and treatment with the potent PARP inhibitor 1,5-isoquinolinediol (3 mg/kg/day, i.p.) could prevent endothelial dysfunction caused by aldosterone.

Methods. Infusion of subpressor doses of aldosterone with subcutaneously implanted mini-osmotic pumps (0.05 mg/kg/day) to rats for 21 days induced the development of endothelial dysfunction. In order to evaluate endothelial function, isometric tension studies were performed in response to acetylcholine and sodium nitroprusside.Additionally, PAR (the end product of activated PARP) and PARP-1 expressions in the endothelium of thoracic aortas were evaluated by immunohistochemistry.

Results. There was a significant loss of endothelium-dependent vasodilatation in response to acetylcholine in aldosterone-infused rats. In animals treated with 1,5-isoquinolinediol, the effect of aldosterone on vascular responsiveness was less than the untreated groups. Immunohistochemical studies demonstrated that aldosterone administration increased PAR and PARP-1 expressions in the endothelium of thoracic aortas, whereas PARP inhibition decreased their expressions to control levels.

Conclusion. Our results indicate that PARP activation in the vascular system may be a contributory factor to the impaired endothelial function associated with aldosterone administration.