Rosiglitazone ameliorates cisplatin-induced renal injury in mice

Leonurine alleviates vancomycin nephrotoxicity via activating PPARγ and inhibiting the TLR4/NF-κB/TNF-α pathway

Vancomycin (VCM) is the first-line antibiotic for severe infections, but nephrotoxicity limits its use. Leonurine (Leo) has shown protective effects against kidney damage. However, the effect and mechanism of Leo on VCM nephrotoxicity remain unclear. In this study, mice and HK-2 cells exposed to VCM were treated with Leo. Biochemical and pathological analysis and fluorescence probe methods were performed to examine the role of Leo in VCM nephrotoxicity. Immunohistochemistry, q-PCR, western blot, FACS, and Autodock software were used to verify the mechanism. The present results indicate that Leo significantly alleviates VCM-induced renal injury, morphological damage, and oxidative stress. Increased intracellular and mitochondrial ROS in HK-2 cells and decreased mitochondrial numbers in mouse renal tubular epithelial cells were reversed in Leo-administrated groups. In addition, molecular docking analysis using Autodock software revealed that Leo binds to the PPARγ protein with high affinity. Mechanistic exploration indicated that Leo inhibited VCM nephrotoxicity via activating PPARγ and inhibiting the TLR4/NF-κB/TNF-α inflammation pathway. Taken together, our results indicate that the PPARγ inhibition and inflammation reactions were implicated in the VCM nephrotoxicity and provide a promising therapeutic strategy for renal injury.

Perfluorooctanoic acid (PFOA) exposure induces renal filtration and reabsorption disorders via down-regulation of aquaporins

Perfluorooctanoic acid (PFOA) exposure is associated with kidney dysfunction, however the exact mechanisms by which PFOA induces nephrotoxicity and the specific involvement of aquaporins (AQPs) in kidney tissue remains unclear. In this study, adult male Sprague-Dawley (SD) rats were exposed to PFOA by oral gavage for 28 days and compared with controls. Body weight, water intake and urine volume were recorded daily. At the end of the experiment, blood and kidney samples were collected, and serum urea, creatine and uric acid levels were assessed. The renal expression levels of water channel proteins AQP1, AQP3, AQP2 and p-AQP2 (Ser256) were observed by immunohistochemical staining, and the corresponding transcription levels were detected by Western blot and qRT-PCR. The results showed that PFOA exposure inhibited weight gain and increased water intake, urine volume, kidney weight and renal visceral index. PASM staining and transmission electron microscopy revealed pathological thickening of the glomerular capsule and basement membrane. Serum urea levels were increased, while serum creatine levels were decreased compared to controls. Additionally, the expression levels of AQP1, AQP3, AQP2 and p-AQP2 in kidney tissues were decreased, and the phosphorylation of AQP2 at Ser256 was inhibited. In conclusion, we demonstrate that PFOA exposure can damage the renal filtration barrier and reduce the expression level of AQPs in renal tissues, leading to renal filtration and reabsorption disorders.

Transcriptomics-based analysis reveals the nephrotoxic effects of triphenyltin (TPT) on SD rats by affecting RAS, AQPs and lipid metabolism

Triphenyltin (TPT) is a class of organotin compounds that are extensively used in industry and agriculture. They have endocrine-disrupting effects and cause severe environmental contamination. Pollutants may accumulate in the kidneys and cause pathological complications. However, the mechanism of TPT's toxicological effects on the kidney remains unclear. This study aimed to investigate the toxic effects and mechanism of action of TPT exposure on renal impairment in rats. Male SD rats were divided into four groups: the Ctrl group (control group), TPT-L group (0.5 mg/kg/d), TPT-M group (1 mg/kg/d), and TPT-H group (2 mg/kg/d). After 28 days of exposure to TPT, we observed the morphology and structure of kidney tissue using HE, PASM, and Masson staining. We also detected serum biochemical indexes, performed transcriptome sequencing of rat kidney tissue using RNA-seq. Furthermore, protein expression levels were measured through immunohistochemistry and gene expression levels were determined using RT-qPCR. The study results indicated a decrease in kidney weight and relative kidney weight after 28 days of exposure to TPT. Additionally, TPT caused damage to kidney structure and function, as evidenced by HE staining, PASM staining, and serum biochemical tests. Transcriptomics identified 352 DEGs, and enrichment analyses revealed that TPT exposure primarily impacted the renin-angiotensin system (RAS). The expression levels of water channel proteins were reduced, and the expression levels of RAS and lipid metabolism-related genes (Mme, Ace, Fasn, Cyp4a8, Cpt1b and Ppard) were significantly decreased in the TPT-treated group. In summary, exposure to TPT may impair renal structure and function in rats by affecting RAS, AQPs, and lipid metabolism.

A Cross-Talk about Radioresistance in Lung Cancer-How to Improve Radiosensitivity According to Chinese Medicine and Medicaments That Commonly Occur in Pharmacies

Lung cancer is one of the most common cancers in the population and is characterized by non-specific symptoms that delay the diagnosis and reduce the effectiveness of oncological treatment. Due to the difficult placement of the tumor, one of the main methods of lung cancer treatment is radiotherapy, which damages the DNA of cancer cells, inducing their apoptosis. However, resistance to ionizing radiation may develop during radiotherapy cycles, leading to an increase in the number of DNA points of control that protect cells from apoptosis. Cancer stem cells are essential for radioresistance, and due to their ability to undergo epithelial-mesenchymal transition, they modify the phenotype, bypassing the genotoxic effect of radiotherapy. It is therefore necessary to search for new methods that could improve the cytotoxic effect of cells through new mechanisms of action. Chinese medicine, with several thousand years of tradition, offers a wide range of possibilities in the search for compounds that could be used in conventional medicine. This review introduces the potential candidates that may present a radiosensitizing effect on lung cancer cells, breaking their radioresistance. Additionally, it includes candidates taken from conventional medicine-drugs commonly available in pharmacies, which may also be significant candidates.

Protective effects of recombinant human golimumab and pentoxifylline in nephrotoxicity induced by cisplatin

In cisplatin-induced nephrotoxicity, the significant role of activation of inflammatory pathways has been reported earlier. Studies indicate elevated expression and activity of tumor necrosis factor-α (TNF-α) in both, serum and kidneys of cisplatin-treated animals. Golimumab, an anti-TNF biologic, has been approved for the management of many inflammatory conditions. This experiment was planned and executed to evaluate the impact of golimumab on renal function, inflammation in cisplatin-induced nephrotoxicity in mice, and oxidative stress. Cisplatin (22 mg/kg) as a single intraperitoneal injection was used to induce nephrotoxicity in mice. Golimumab was administered at 24 mg/kg for 7 days by subcutaneous route. Pentoxifylline (PTX) was administered for 7 days (150 mg/kg) as a reference standard. Renal functions, oxidative stress, and inflammation were evaluated on the seventh day. Cisplatin administration in mice caused a significant rise in serum cystatin C, creatinine, blood urea nitrogen, and neutrophil gelatinase-associated lipocalin. A significant rise of urinary clusterin, kidney injury molecule-1, and β-N-acetylglucosaminidase levels was also seen in cisplatin-treated animals. Furthermore, cisplatin-induced nephrotoxicity was associated with a significant increase in oxidative stress and inflammation in serum and kidneys. Golimumab treatment significantly prevented the cisplatin-induced alteration in markers of renal function and renal damage. There was a significant reduction in oxidative stress and inflammation in golimumab-treated animals. Furthermore, the histopathological evaluation also revealed inverted changes in the proximal tubules after golimumab treatment in kidneys after cisplatin toxicity. The standard drug, PTX, also prevented nephrotoxicity caused by cisplatin as indicated by the recovery in renal function, reduction in oxidative stress and inflammation. These results indicate that golimumab was effective in nephrotoxicity induced by cisplatin through inhibition of oxidative stress, and inflammatory response.

An Activatable Near-Infrared Fluorescence Probe for in Vivo Imaging of Acute Kidney Injury by Targeting Phosphatidylserine and Caspase-3

Renal-clearable and target-responsive near-infrared (NIR) fluorescent imaging probes have been promising for in vivo diagnosis of acute kidney injury (AKI). However, designing an imaging probe that is renal-clearable and concurrently responsive toward multiple molecular targets to facilitate early detection of AKI with improved sensitivity and specificity is challenging. Herein, by leveraging the receptor-mediated binding and retention effect along with enzyme-triggered fluorescence activation, we design and synthesize an activatable small-molecule NIR fluorescent probe (1-DPA2) using a "one-pot sequential click reaction" approach. 1-DPA2 can target both the externalized phosphatidylserine (PS) and active caspase-3 (Casp-3), two essential biomarkers of apoptosis, producing enhanced 808 nm NIR fluorescence and a high signal-to-background ratio (SBR) amenable to detecting the onset of cisplatin-induced AKI in mice as early as 24 h post-treatment with cisplatin. We not only monitor the gradual activation of Casp-3 in the kidney of mice upon AKI progression but also can report on the progressive recovery of kidney functions in AKI mice following N-acetyl-l-cysteine (NAC) therapy via real-time fluorescence imaging by 1-DPA2. This study demonstrates the ability of 1-DPA2 for longitudinal monitoring of renal cell apoptosis by concurrently targeting PS externalization and Casp-3 activation, which is efficient for early diagnosis of AKI and useful for prediction of potential drug nephrotoxicity as well as in vivo screening of anti-AKI drugs' efficacy.

Mitigation of cisplatin induced nephrotoxicity by casticin in male albino rats

Cisplatin (CP) is a commonly used, powerful antineoplastic drug, having numerous side effects. Casticin (CAS) is considered as a free radical scavenger and a potent antioxidant. The present research was planned to assess the curative potential of CAS on CP persuaded renal injury in male albino rats. Twenty four male albino rats were distributed into four equal groups. Group-1 was considered as a control group. Animals of Group-2 were injected with 5mg/kg of CP intraperitoneally. Group-3 was co-treated with CAS (50mg/kg) orally and injection of CP (5mg/kg). Group-4 was treated with CAS (50mg/kg) orally throughout the experiment. CP administration substantially reduced the activities of catalase (CAT), superoxide dismutase (SOD), peroxidase (POD), glutathione S-transferase (GST), glutathione reductase (GSR), glutathione (GSH) content while increased thiobarbituric acid reactive substances (TBARS), and hydrogen peroxide (H2O2) levels. Urea, urinary creatinine, urobilinogen, urinary proteins, kidney injury molecule-1 (KIM-1), and neutrophil gelatinase-associated lipocalin (NGAL) levels were substantially increased. In contrast, albumin and creatinine clearance was significantly reduced in CP treated group. The results demonstrated that CP significantly increased the inflammation indicators including nuclear factor kappa-B (NF-κB), tumor necrosis factor-α (TNF-α), Interleukin-1β (IL-1β), Interleukin-6 (IL-6) levels and cyclooxygenase-2 (COX-2) activity and histopathological damages. However, the administration of CAS displayed a palliative effect against CP-generated renal toxicity and recovered all parameters by bringing them to a normal level. These results revealed that the CAS is an effective compound having the curative potential to counter the CP-induced renal damage.

Conventional Chemotherapy Nephrotoxicity

Conventional chemotherapies remain the mainstay of treatment for many malignancies. Kidney complications of these therapies are not infrequent and may have serious implications for future kidney function, cancer treatment options, eligibility for clinical trials, and overall survival. Kidney adverse effects may include acute kidney injury (via tubular injury, tubulointerstitial nephritis, glomerular disease and thrombotic microangiopathy), long-term kidney function loss and CKD, and electrolyte disturbances. In this review, we summarize the kidney complications of conventional forms of chemotherapy and, where possible, provide estimates of incidence, and identify risk factors and strategies for kidney risk mitigation. In addition, we provide recommendations regarding kidney dose modifications, recognizing that these adjustments may be limited by available supporting pharmacokinetic and clinical outcomes data. We discuss management strategies for kidney adverse effects associated with these therapies with drug-specific recommendations. We focus on frequently used anticancer agents with established kidney complications, including platinum-based chemotherapies (cisplatin, carboplatin, oxaliplatin), cyclophosphamide, gemcitabine, ifosfamide, methotrexate and pemetrexed, among others.

Overexpression of aquaporin 2 in renal tubular epithelial cells alleviates pyroptosis

Background

Severe renal ischemia-reperfusion injury results in worse outcomes of kidney transplantation. Compared to the collecting duct, the proximal tubule is more likely to exhibit severe pyroptosis and damage during renal ischemia-reperfusion. Aquaporins were reported of having regulatory roles in pyroptosis. We explored whether aquaporin 2 overexpression in proximal tubular cells could alleviate ischemia-reperfusion injury related pyroptosis.

Methods

A renal ischemia-reperfusion model of mice was established, and human kidney 2 cells were treated with hypoxia-reoxygenation. Aquaporin 2 overexpression was achieved in human kidney 2 cells transfected with lentivirus, which were then cultured with murine cells. Renal tissues and serum of the mice, and human kidney 2 cells were subjected to histological, molecular, and biochemical examinations.

Results

Compared with the sham group, the renal function of the ischemia-reperfusion group was significantly decreased, and the tissue injury was severe and accompanied by more nuclear dissolved and necrosis. Besides, the expression of aquaporin 1-5 decreased significantly, while the expression of Toll-like receptor 4, caspase-1, kim-1 and interleukin 1β and 18 increased significantly in ischemia-reperfusion group. Similar results were observed in the human kidney 2 cells test. Overexpression of aquaporin 2 partially reversed the cell damage, pyroptosis, and molecular expression changes of human kidney 2 cells induced by hypoxia-reoxygenation.

Conclusions

Our findings suggest that aquaporin 2 overexpression can potentially reduce pyroptosis in proximal tubular cells, and thus might be a novel target for relieving pyroptosis and injury in renal ischemia-reperfusion injury.

Nephroprotective effect of ethanol extract and fractions of a sea lettuce, Ulva fasciata against cisplatin-induced kidney injury in rats

Cisplatin is widely used in anticancer therapy, but a substantial percentage of patients who receive the therapeutic dose of cisplatin develop nephrotoxicity. Hepatotoxicity may also develop after a single dose or low repeated doses of cisplatin. Ulva fasciata is an edible seaweed, commonly known as sea lettuces have also been shown various biological activities. In this study, ethanol extract and its solvent fractions (n-hexane and chloroform) of U. fasciata were given (orally) to different groups of rats for 10 days. Injury to the kidney was induced by administrating cisplatin, intraperitoneally (i.p.) to rats at a dose of 7 mg/kg body weight (b.w.) dissolved in 1 mL saline, at 5th day of the experiment. At 10th day rats were sacrificed and kidney parameters (creatinine, urea, and blood urea nitrogen (BUN)) and electrolyte balance (Ca⁺⁺, Mg⁺⁺, K+, and Na⁺) in serum were determined, while oxidative stress markers glutathione (GSH), catalase (CAT) and malondialdehyde (MDA), and inflammatory cytokines, tumor necrosis factor (TNF α), and interleukin (IL-6) were determined in kidney tissues. Histological examination of the kidney was also performed to examine the changes in kidney tissues. Cisplatin caused adverse effects on blood parameters, antioxidants, and inflammatory markers with severe renal tubular injury in kidney tissues. Ethanol extract of U. fasciata and its fractions effectively improved these disorders and diminished the renal dysfunction. However, ethanol extract was found more effective in attenuating the adverse effect of cisplatin than its fractions. n-Hexane-soluble fraction that was subjected to GC-FID and GC-MS analysis revealed the presence of several compounds and some of them are new from this source. It could be concluded that the U. fasciata possesses nephroprotective effect and can attenuate cisplatin-induced renal dysfunction. Since U. fasciata is an edible seaweed, it may be used as a diet supplement.

The protective efficacy of vitamin E and cod liver oil against cisplatin-induced acute kidney injury in rats

Cisplatin (CP) is a highly effective chemotherapeutic agent against neoplasms, but its clinical utility is limited due to the side effects of its dose-dependent nephrotoxicity. Vitamin E (Vit E) and cod liver oil (CLO) are natural substances with chemoprotective effects. The present study was conducted to evaluate the protective effects of Vit E and/or CLO for CP-induced acute kidney injury (AKI) in rats. This study involved 40 mature male Wistar albino rats that were equally allocated into eight groups: Veh, Vit E, CLO, Vit E + CLO, CP, Vit E + CP, CLO + CP, and Vit E + CLO + CP. The co-administration of Vit E and CLO significantly ameliorated CP-induced elevations in serum creatinine (Cr), blood urea nitrogen (BUN), interleukin 1 beta (IL-1β), and interleukin- 6 (IL-6). Further, rats that received Vit E and/or CLO showed significant decrease in malondialdehyde (MDA) and increases in superoxide dismutase (SOD), catalase (CAT), and glutathione (GSH) levels in renal tissues, compared to CP-intoxicated rats. Additionally, the treatment restored the normal histological architecture (except for few cast formations) and upregulated the immunostaining area% of aquaporin 3 (AQP3) and downregulated the immunostaining area% of Bcl2 associated X protein (BAX) and inducible nitric oxide synthase (iNOS). The observed effects were stronger in the combination treatment group. The obtained data revealed that Vit E and CLO co-administration protects against the CP-induced AKI more than monotherapy with Vit E or CLO.

Renoprotective and haemodynamic effects of adiponectin and peroxisome proliferator-activated receptor agonist, pioglitazone, in renal vasculature of diabetic Spontaneously hypertensive rats

Pioglitazone, a therapeutic drug for diabetes, possesses full PPAR-γ agonist activity and increase circulating adiponectin plasma concentration. Plasma adiponectin concentration decreases in hypertensive patients with renal dysfunctions. Present study investigated the reno-protective, altered excretory functions and renal haemodynamic responses to adrenergic agonists and ANG II following separate and combined therapy with pioglitazone in diabetic model of hypertensive rats. Pioglitazone was given orally [10mg/kg/day] for 28 days and adiponectin intraperitoneally [2.5μg/kg/day] for last 7 days. Groups of SHR received either pioglitazone or adiponectin in combination. A group of Wistar Kyoto rats [WKY] served as normotensive controls, whereas streptozotocin administered SHRs served as diabetic hypertensive rats. Metabolic data and plasma samples were taken on day 0, 8, 21 and 28. In acute studies, the renal vasoconstrictor actions of Angiotensin II [ANGII], noradrenaline [NA], phenylephrine [PE] and methoxamine [ME] were determined. Diabetic SHRs control had a higher basal mean arterial blood pressure than the WKY, lower RCBP and plasma adiponectin, higher creatinine clearance and urinary sodium excretion compared to WKY [all P<0.05] which were normalized by the individual drug treatments and to greater degree following combined treatment. Responses to intra-renal administration of NA, PE, ME and ANGII were larger in diabetic SHR than WKY and SHRs [P<0.05]. Adiponectin significantly blunted responses to NA, PE, ME and ANG II in diabetic treated SHRs by 40%, whereas the pioglitazone combined therapy with adiponectin further attenuated the responses to adrenergic agonists by 65%. [all P <0.05]. These findings suggest that adiponectin possesses renoprotective effects and improves renal haemodynamics through adiponectin receptors and PPAR-γ in diabetic SHRs, suggesting that synergism exists between adiponectin and pioglitazone. A cross-talk relationship also supposed to exists between adiponectin receptors, PPAR-γ and alpha adrenoceptors in renal vasculature of diabetic SHRs.

Vernonia cinerea regenerates tubular epithelial cells in cisplatin induced nephrotoxicity in cancer bearing mice without affecting antitumor activity

Background

Traditional Siddha Medicine advises using metal-based formulations to treat cancers. In the case of any toxicities during the therapy, Siddha physicians use Vernonia cinerea (VC) whole plant kashayam (crude aqueous extract-CAE) to reverse the toxic effects.

Aim

To evaluate the nephroprotective activity of CAE and its fractions in cisplatin-induced nephrotoxicity and to assess whether they compromise the anticancer efficacy of cisplatin.

Materials and methods

Cisplatin-induced renal damage was induced in Ehrlich Ascites Carcinoma (EAC) bearing mice during mild phase of tumor growth. CAE and its butanol (BF) and aqueous (AF) fractions were administered orally from the 5th day for five days. Nephroprotective potential (serum urea, creatinine, renal histology) and effect of VC on cisplatin anticancer efficacy (tumor volume, viable tumor cells, percentage increase in life span (% ILS)) were calculated.

Result

CAE and its fractions significantly reversed the cisplatin-induced renal damage. CAE and BF treated animals showed regeneration of 50%–75% of proximal tubular cells. Compared to EAC control mice, the % ILS of the cisplatin-treated group was 244% and it was further extended to 379% after CAE administration. The % ILS in the CAE treated group was 1.6 times higher than the cisplatin alone treated group. GC-MS study showed the presence of astaxanthin and betulin.

Conclusion

CAE of VC reverses cisplatin-induced kidney damage as well as regenerates proximal tubular epithelial cells, without compromising the anticancer effect of cisplatin. When CAE was further fractionated, the nephroprotective activity was retained, but the beneficial anticancer effect of cisplatin was compromised.

•

Vernonia cinerea (VC) significantly reverses cisplatin-induced kidney damage.

•

VC regenerates the damaged proximal tubular epithelial cells.

•

VC did not compromise the anticancer beneficial effect of cisplatin.

•

Fractionation of VC lead to compromising of cisplatin anticancer effect.

•

Astaxanthin and betulin present in VC could be resposible for its nephroprotective effect.

PPARγ Agonists in Combination Cancer Therapies

Peroxisome proliferator-activated receptor-gamma (PPARγ) is a nuclear receptor acting as a transcription factor involved in the regulation of energy metabolism, cell cycle, cell differentiation, and apoptosis. These unique properties constitute a strong therapeutic potential that place PPARγ agonists as one of the most interesting and widely studied anticancer molecules. Although PPARγ agonists exert significant, antiproliferative and tumoricidal activity in vitro, their anticancer efficacy in animal models is ambiguous, and their effectiveness in clinical trials in monotherapy is unsatisfactory. However, due to pleiotropic effects of PPARγ activation in normal and tumor cells, PPARγ ligands interact with many antitumor treatment modalities and synergistically potentiate their effectiveness. The most spectacular example is a combination of PPARγ ligands with tyrosine kinase inhibitors (TKIs) in chronic myeloid leukemia (CML). In this setting, PPARγ activation sensitizes leukemic stem cells, resistant to any previous form of treatment, to targeted therapy. Thus, this combination is believed to be the first pharmacological therapy able to cure CML patients. Within the last decade, a significant body of data confirming the benefits of the addition of PPARγ ligands to various antitumor therapies, including chemotherapy, hormonotherapy, targeted therapy, and immunotherapy, has been published. Although the majority of these studies have been carried out in vitro or animal tumor models, a few successful attempts to introduce PPARγ ligands into anticancer therapy in humans have been recently made. In this review, we aim to summarize shines and shadows of targeting PPARγ in antitumor therapies.

Galectin 3 protects from cisplatin-induced acute kidney injury by promoting TLR-2-dependent activation of IDO1/Kynurenine pathway in renal DCs

Strategies targeting cross-talk between immunosuppressive renal dendritic cells (DCs) and T regulatory cells (Tregs) may be effective in treating cisplatin (CDDP)-induced acute kidney injury (AKI). Galectin 3 (Gal-3), expressed on renal DCs, is known as a crucial regulator of immune response in the kidneys. In this study, we investigated the role of Gal-3 for DCs-mediated expansion of Tregs in the attenuation of CDDP-induced AKI. Methods: AKI was induced in CDDP-treated wild type (WT) C57BL/6 and Gal-3 deficient (Gal-3^-/-) mice. Biochemical, histological analysis, enzyme-linked immunosorbent assay (ELISA), immunohistochemistry, real-time PCR, magnetic cell sorting, flow cytometry and intracellular staining of renal-infiltrated immune cells were used to determine the differences between CDDP-treated WT and Gal-3^-/- mice. Newly synthesized selective inhibitor of Gal-3 (Davanat) was used for pharmacological inhibition of Gal-3. Recombinant Gal-3 was used to demonstrate the effects of exogenously administered soluble Gal-3 on AKI progression. Pam3CSK4 was used for activation of Toll-like receptor (TLR)-2 in DCs. Cyclophosphamide or anti-CD25 antibody were used for the depletion of Tregs. 1-Methyl Tryptophan (1-MT) was used for pharmacological inhibition of Indoleamine 2,3-dioxygenase-1 (IDO1) in TLR-2-primed DCs which were afterwards used in passive transfer experiments. Results: CDDP-induced nephrotoxicity was significantly more aggravated in Gal-3^-/- mice. Significantly reduced number of immunosuppressive TLR-2 and IDO1-expressing renal DCs, lower serum levels of KYN, decreased presence of IL-10-producing Tregs and significantly higher number of inflammatory IFN-γ and IL-17-producing neutrophils, Th1 and Th17 cells were observed in the CDDP-injured kidneys of Gal-3^-/- mice. Pharmacological inhibitor of Gal-3 aggravated CDDP-induced AKI in WT animals while recombinant Gal-3 attenuated renal injury and inflammation in CDDP-treated Gal-3^-/- mice. CDDP-induced apoptosis, driven by Bax and caspase-3, was aggravated in Gal-3^-/- animals and in WT mice that received Gal-3 inhibitor (CDDP+Davanat-treated mice). Recombinant Gal-3 managed to completely attenuate CDDP-induced apoptosis in CDDP-injured kidneys of Gal-3^-/- mice. Genetic deletion as well as pharmacological inhibition of Gal-3 in renal DCs remarkably reduced TLR-2-dependent activation of IDO1/KYN pathway in these cells diminishing their capacity to prevent transdifferentiation of Tregs in inflammatory Th1 and Th17 cells. Additionally, Tregs generated by Gal-3 deficient DCs were not able to suppress production of IFN-γ and IL-17 in activated neutrophils. TLR-2-primed DCs significantly enhanced capacity of Tregs for attenuation of CDDP-induced AKI and inflammation and expression of Gal-3 on TLR-2-primed DCs was crucially important for their capacity to enhance nephroprotective and immunosuppressive properties of Tregs. Adoptive transfer of TLR-2-primed WTDCs significantly expanded Tregs in the kidneys of CDDP-treated WT and Gal-3^-/- recipients resulting in the suppression of IFN-γ and IL-17-driven inflammation and alleviation of AKI. Importantly, this phenomenon was not observed in CDDP-treated WT and Gal-3^-/- recipients of TLR-2-primed Gal-3^-/-DCs. Gal-3-dependent nephroprotective and immunosuppressive effects of renal DCs was due to the IDO1-induced expansion of renal Tregs since either inhibition of IDO1 activity in TLR-2-primed DCs or depletion of Tregs completely diminished DCs-mediated attenuation of CDDP-induced AKI. Conclusions: Gal-3 protects from CDDP-induced AKI by promoting TLR-2-dependent activation of IDO1/KYN pathway in renal DCs resulting in increased expansion of immunosuppressive Tregs in injured kidneys. Activation of Gal-3:TLR-2:IDO1 pathway in renal DCs should be further explored as new therapeutic approach for DC-based immunosuppression of inflammatory renal diseases.

MDM2 inhibitor ameliorates cisplatin-induced nephropathy via NFκΒ signal inhibition

Cisplatin is a platinum-containing chemotherapeutic drug, which is widely used and highly effective. While effective against tumors, its use is limited by severe side effects such as nephrotoxicity and bone marrow suppression. Murine double minute 2 (MDM2) is the E3 ubiquitin ligase of the tumor suppressor gene, p53, and inhibition of MDM2 can suppress tumor cell growth. However, independent of p53, MDM2 acts as a co-transcription factor for nuclear factor-κB (NFκB), whose signaling can be involved in cisplatin-induced tubular injury. We therefore examined the effects of MDM2 inhibitor on cisplatin cytotoxicity. In order to induce acute kidney injury and to investigate MDM2 inhibitory effects, we injected cisplatin into rats with or without the MDM2 inhibitor, DS-5272, and analyzed kidney physiology/histology and NFκB signaling. Serum creatinine was significantly lower in the DS-5272 group than in the vehicle group on day 3 (0.55 ± 0.069 vs 0.70 ± 0.072 mg/dL, P < 0.05). DS-5272 also significantly decreased kidney injury molecule-1 (KIM-1) expression, improved tubular injury, and decreased apoptotic cells. Western blotting showed that cisplatin increased NFκB phosphorylation in kidneys, which was significantly suppressed by DS-5272. In vitro, we treated HEK 293 cells with cisplatin, in the absence or presence of DS-5272, and examined cytotoxicity and NFκB transcriptional activity. DS-5272 co-treatment reduced both cisplatin-induced cell death and NFκB transcriptional activity. Collectively, these findings suggest that DS-5272 can ameliorate cisplatin nephrotoxicity via NFκB signal inhibition.

Protective effect of rosiglitazone on chronic renal allograft dysfunction in rats

BACKGROUND

Chronic renal allograft dysfunction (CRAD) is the main condition affecting the long-term survival of renal allografts. Rosiglitazone, which is a peroxisome proliferator-activated receptor-γ (PPAR-γ) agonist, has been shown to exert antifibrotic and anti-inflammatory effects on some renal diseases. The present paper investigates the effect of rosiglitazone on CRAD using a murine model.

METHODS

The CRAD group received classical orthotopic F344-Lewis kidney transplantation. The treatment group was treated with rosiglitazone for 12 weeks following renal transplantation. The control subjects were uninephrectomized F344 and Lewis rats. Twelve weeks after the operation, the rats were harvested for renal function, histological, immunohistochemical and molecular biological analyses.

RESULTS

Rosiglitazone treatment effectively decreased urine protein excretion and preserved renal function in the CRAD rats. Administration of rosiglitazone also inhibited interstitial fibrosis and macrophage infiltration in the CRAD rat kidneys. Furthermore, rosiglitazone treatment inhibited TGF-β and NF-κB pathway activation, decreased collagen I, collagen IV, α-SMA, MCP-1, ICAM-1, TNF-α, and IL-1β expression, and increased E-cadherin expression in renal allograft tissues from the CRAD rats.

CONCLUSIONS

Rosiglitazone successfully attenuates the development of CRAD via inhibition of TGF-β signaling, the renal tubular epithelial-to-mesenchymal transition (EMT), and inflammation.

Deciphering the SUMO code in the kidney

SUMOylation of proteins is an important regulatory element in modulating protein function and has been implicated in the pathogenesis of numerous human diseases such as cancers, neurodegenerative diseases, brain injuries, diabetes, and familial dilated cardiomyopathy. Growing evidence has pointed to a significant role of SUMO in kidney diseases such as DN, RCC, nephritis, AKI, hypertonic stress and nephrolithiasis. Recently, emerging studies in podocytes demonstrated that SUMO might have a protective role against podocyte apoptosis. However, the SUMO code responsible for beneficial outcome in the kidney remains to be decrypted. Our recent experiments have revealed that the expression of both SUMO and SUMOylated proteins is appreciably elevated in hypoxia‐induced tubular epithelial cells (TECs) as well as in the unilateral ureteric obstruction (UUO) mouse model, suggesting a role of SUMO in TECs injury and renal fibrosis. In this review, we attempt to decipher the SUMO code in the development of kidney diseases by summarizing the defined function of SUMO and looking forward to the potential role of SUMO in kidney diseases, especially in the pathology of renal fibrosis and CKD, with the goal of developing strategies that maximize correct interpretation in clinical therapy and prognosis.

A novel dual PPAR-γ agonist/sEH inhibitor treats diabetic complications in a rat model of type 2 diabetes

AIMS/HYPOTHESIS

The metabolic syndrome is a cluster of risk correlates that can progress to type 2 diabetes. The present study aims to evaluate a novel molecule with a dual action against the metabolic syndrome and type 2 diabetes.

METHODS

We developed and tested a novel dual modulator, RB394, which acts as a soluble epoxide hydrolase (sEH) inhibitor and a peroxisome proliferator-activated receptor-γ (PPAR-γ) agonist in rat models of the metabolic syndrome-the obese spontaneously hypertensive (SHROB) rat and the obese diabetic Zucker fatty/spontaneously hypertensive heart failure F1 hybrid (ZSF1) rat. In SHROB rats we studied the ability of RB394 to prevent metabolic syndrome phenotypes, while in ZSF1 obese diabetic rats we compared RB394 with the ACE inhibitor enalapril in the treatment of type 2 diabetes and associated comorbid conditions. RB394 (10 mg/kg daily) and enalapril (10 mg/kg daily) were administered orally for 8 weeks.

RESULTS

RB394 blunted the development of hypertension, insulin resistance, hyperlipidaemia and kidney injury in SHROB rats and reduced fasting blood glucose and HbA_1c, improved glucose tolerance, reduced blood pressure and improved lipid profiles in obese ZSF1 rats. A reduction in liver fibrosis and hepatosteatosis was evident in RB394-treated obese ZSF1 rats. Unlike RB394, enalapril did not demonstrate any positive effects in relation to diabetes, hyperlipidaemia or liver dysfunction in obese ZSF1 rats. RB394 ameliorated diabetic nephropathy by reducing renal interstitial fibrosis and renal tubular and glomerular injury in obese diabetic ZSF1 rats. Intriguingly, enalapril demonstrated a weaker action against diabetic nephropathy in obese ZSF1 rats.

CONCLUSIONS/INTERPRETATION

These findings demonstrate that a novel sHE inhibitor/PPAR-γ agonist molecule targets multiple risk factors of the metabolic syndrome and is a glucose-lowering agent with a strong ability to treat diabetic complications.

Cisplatin-Induced Rodent Model of Kidney Injury: Characteristics and Challenges

Cisplatin is an antitumor drug used in the treatment of a wide variety of malignancies. However, its primary dose-limiting side effect is kidney injury, which is a major clinical concern. To help understand mechanisms involved in the development of kidney injury, cisplatin rodent model has been developed. Given the complex pathogenesis of kidney injury, which involves both local events in the kidney and interconnected and interdependent systemic effects in the body, cisplatin rodent model is indispensable in the investigation of underlying mechanisms and potential treatment strategies of both acute and chronic kidney injury. Cisplatin rodent model is well appreciated and widely used model due to its simplicity. It has many similarities to human cisplatin nephrotoxicity, which are mentioned in the paper. In spite of its simplicity and wide applicability, there are also traps that need to be taken into account when using cisplatin model. The present paper is aimed at giving a concise insight into the complex characteristics of cisplatin rodent model and heterogeneity of cisplatin dosage regimens as well as outlining factors that can severely influence the outcome of the model and the study. Challenges for future research are also mentioned.

Dunnione protects against experimental cisplatin-induced nephrotoxicity by modulating NQO1 and NAD+ levels

Despite being an efficacious anticancer agent, the clinical utility of cisplatin is hindered by its cardinal side effects. This investigation aimed to appraise potential protective impact of dunnione, a natural naphthoquinone pigment with established NQO1 stimulatory effects, on cisplatin nephrotoxicity of rats. Dunnione was administered orally at 10 and 20 mg/kg doses for 4 d and a single injection of cisplatin was delivered at the second day. Renal histopathology, inflammatory/oxidative stress/apoptotic markers, kidney function, and urinary markers of renal injury were assessed. Dunnione repressed cisplatin-induced inflammation in the kidneys as indicated by decreased TNF-α/IL-1β levels, and reduced nuclear phosphorylated NF-κB p65. This agent also obviated cisplatin-invoked oxidative stress as elucidated by decreased MDA/GSH levels and increased SOD/CAT activities. Dunnione, furthermore, improved renal histological deteriorations as well as caspase-3 activities and terminal deoxynucleotidyl transferase (TUNEL) positive cells, the indicators of apoptosis. Moreover, it up-regulated nuclear Nrf2 and cytosolic haeme-oxygenase-1 (HO-1) and NQO1 levels; meanwhile, promoted NAD⁺/NADH ratios followed by enhancing the activities of Sirt1 and PARP1; and further attenuated nuclear acetylated NF-κB p65. Dunnione additionally declined cisplatin-evoked retrogression in renal function and upraise in urinary markers of glomerular and tubular injury as demonstrated by decreased serum urea and creatinine with simultaneous reductions in urinary excretions of collagen type IV, podocin, cystatin C, and retinol-binding protein (RBP). Altogether, these findings offer dunnione as a potential protective agent against cisplatin-induced nephrotoxicity in rats.

Protein extracted from Porphyra yezoensis prevents cisplatin-induced nephrotoxicity by downregulating the MAPK and NF-κB pathways

Acute renal failure is a serious complication of treatment with the anticancer drug cisplatin. Cisplatin exerts a cytotoxic effect on renal cells by inducing apoptosis through activating the tumor suppressor p53, nuclear factor‑κB (NF‑κB) and mitogen‑activated protein kinase (MAPK)/p38 pathways. Effects of protein extracts of the brown seaweed Porphyra yezoensis (P. yezoensis) on cytotoxicity, inflammation and cell proliferation have been reported; however, the effects of P. yezoensis protein (PYP) extract on cisplatin‑induced renal injury have remained elusive. The present study investigated the effects of PYP on cisplatin‑induced nephrotoxicity in the HK2 human proximal tubular epithelial cell line. PYP treatment reduced cisplatin‑induced apoptosis and death of HK2 cells by restoring the B‑cell lymphoma‑2 (Bcl‑2)‑associated X protein (Bax)/Bcl‑2 imbalance, cytochrome c release and caspase‑3 activation. In addition, PYP activated the redox‑sensitive transcription factor NF‑κB via stimulating the nuclear translocation of p65 in HK2 cells. PYP also restored renal antioxidant levels and increased the total and nuclear accumulation of NF erythroid 2‑related factor 2 in HK2 cells. PYP markedly attenuated cisplatin‑induced p38, MAPK and c‑Jun N‑terminal kinase phosphorylation. Furthermore, treatment with PYP ameliorated cisplatin‑induced renal cell damage by upregulating antioxidant defense mechanisms and downregulating the MAPK and NF‑κB signaling pathways. In addition, mice were divided into three treatment groups (control, cisplatin and PYP + cisplatin) and the effects of PYP were evaluated in a mouse model of cisplatin‑induced acute kidney injury. The concentrations of blood urea nitrogen and serum creatinine in the PYP + cisplatin group were lower than those in the cisplatin group. The mRNA expression levels of inflammatory factors interleukin‑6 (IL‑6), IL‑1β, tumor necrosis factor‑α and monocyte chemoattractant protein‑1 in the kidney tissues of the PYP + cisplatin group were also lower than those in the cisplatin group. These results suggest that PYP treatment had a preventive effect on nephrotoxicity, specifically by downregulating the MAPK and NF‑κB signaling pathways and the mRNA levels of inflammatory genes.

Ameliorative effects of pine bark extract on cisplatin-induced acute kidney injury in rats

Objective: This study investigated the dose–response effects of pine bark extract (PBE, pycnogenol^®) on oxidative stress-mediated apoptotic changes induced by cisplatin (Csp) in rats.

Materials and methods: The ameliorating potential of PBE was evaluated after orally administering PBE at doses of 10 or 20 mg/kg for 10 days. Acute kidney injury was induced by a single intraperitoneal injection of Csp at 7 mg/kg on test day 5.

Results: Csp treatment caused acute kidney injury manifested by elevated levels of serum blood urea nitrogen (BUN) and creatinine (CRE) with corresponding histopathological changes, including degeneration of tubular epithelial cells, hyaline casts in the tubular lumen, and inflammatory cell infiltration (interstitial nephritis). Csp also induced significant apoptotic changes in renal tubular cells. In addition, Csp treatment induced high levels of oxidative stress, as evidenced by an increased level of malondialdehyde, depletion of the reduced glutathione (GSH) content, and decreased activities of glutathione S-transferase, superoxide dismutase, and catalase in kidney tissues. On the contrary, PBE treatment lowered BUN and CRE levels and effectively attenuated histopathological alterations and apoptotic changes induced by Csp. Additionally, treatment with PBE suppressed lipid peroxidation, prevented depletion of GSH, and enhanced activities of the antioxidant enzymes in kidney tissue.

Conclusions: These results indicate that PBE has a cytoprotective effect against oxidative stress-mediated apoptotic changes caused by Csp in the rat kidney, which may be attributed to both increase of antioxidant enzyme activities and inhibition of lipid peroxidation.

TNF-α, IL-6 and IL-10 expressions, responsible for disparity in action of curcumin against cisplatin-induced nephrotoxicity in rats

Cisplatin is a regularly employed effective chemotherapeutic agent for the treatment of many types of cancer. The main drawback of cisplatin treatment is kidney toxicity which affects 25-35% of treated patients. Many mechanisms are believed to be involved in this kidney damage, but inflammation plays a significant role in this event. Curcumin is a polyphenol and has antioxidant and anti-inflammatory effects. The purpose of this study was to determine the protective effects of curcumin on cisplatin-induced nephrotoxicity. Female rats were randomly divided into 5 groups: control, curcumin, cisplatin, curcumin plus cisplatin (pre-treatment group) and cisplatin plus curcumin (post-treatment group). Rats were given cisplatin (7.5 mg/kg body weight) with or without curcumin treatment (120 mg/kg body weight). Blood urea nitrogen (BUN), creatinine, albumin, tumour necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6, IL-8, IL-10 expressions and histological changes were determined on the 5th day after cisplatin injection. Acute kidney damage was evident by increased BUN and creatinine levels. In addition, cisplatin showed a marked pro-inflammatory response as revealed by a significant increase in the tissue levels of TNF-α, IL-6, IL-8 and decrease in the IL-10 level. Pre-treatment of curcumin reduced cisplatin-induced nephrotoxicity which was clearly evident from the reduced BUN, creatinine, TNF-α, IL-6 and IL-8 levels and increased albumin and IL-10 levels. Additionally, these findings were also supported by histopathology of the kidneys. In contrast, post-treatment of curcumin failed to cut down the expression of inflammatory markers substantially and also neglected to increase the expression of IL-10. The disparity in the action of curcumin after pre- and post-treatment with cisplatin-induced nephrotoxicity was due to the inability of post-treatment to reduce TNF-α & IL-6, besides to show a concurrent rise in IL-10 expression in renal tissues.

Macrophages in kidney injury, inflammation, and fibrosis

Macrophages are found in normal kidney and in increased numbers in diseased kidney, where they act as key players in renal injury, inflammation, and fibrosis. Macrophages are highly heterogeneous cells and exhibit distinct phenotypic and functional characteristics in response to various stimuli in the local microenvironment in different types of kidney disease. In kidney tissue necrosis and/or infection, damage- and/or pathogen-associated molecular patterns induce pro-inflammatory macrophages, which contribute to further tissue injury, inflammation, and subsequent fibrosis. Apoptotic cells and anti-inflammatory factors in post-inflammatory tissues induced anti-inflammatory macrophages, which can mediate kidney repair and regeneration. This review summarizes the role of macrophages with different phenotypes in kidney injury, inflammation, and fibrosis in various acute and chronic kidney diseases. Understanding alterations of kidney microenvironment and the factors that control the phenotype and functions of macrophages may offer an avenue for the development of new cellular and cytokine/growth factor-based therapies as alternative treatment options for patients with kidney disease.

The peroxisome proliferator-activated receptor γ agonist pioglitazone prevents NF-κB activation in cisplatin nephrotoxicity through the reduction of p65 acetylation via the AMPK-SIRT1/p300 pathway

The thiazolidinedione pioglitazone, which is also a PPAR-γ agonist, now is widely used in patients with hypercholesterolemia and hypertriglyceridemia. NF-κB is a ubiquitously expressed transcription factor controlling the expression of numerous genes involved in inflammation. The aim of the present study was to evaluate whether the activation of PPAR-γ attenuates the cisplatin-induced NF-κB activation in cisplatin nephrotoxicity. The results showed that the PPAR-γ agonist pioglitazone decreased the expression of NF-κB p65 transcription target genes (e.g., IL-6, IL-1β, and TNF-α) and inhibited histological injury and inflammatory cells infiltration in cisplatin nephrotoxicity. The suppression of NF-κB activity following pioglitazone treatment inhibited the cisplatin-induced IκB-α degredation and NF-κB p65 subunit translocation. Translocation of the NF-κB p65 subunit depends on p65 acetylation, which primarily regulated by SIRT1 or p300. Notably, AMP kinase (AMPK) activation not only decreased the phosphorylation, activation and p65 interaction of p300 but also increased SIRT1 expression, activation and p65 binding, thus leading to a significant reduction in p65 acetylation. Interestingly, the reduction of IL-6, TNF-α and IL-1β, the inhibition of histological injury and the inflammatory cells infiltration following pioglitazone treatment in cisplatin nephrotoxicity were attenuated after treatment with the PPAR-γ antagonist GW9662. These results suggest that the PPAR-γ agonist pioglitazone prevents NF-κB activation in cisplatin nephrotoxicity through a reduction in p65 acetylation via the AMPK-SIRT1/p300 pathway.

Rosiglitazone attenuates indoxyl sulphate-induced endothelial dysfunction

Indoxyl sulphate is a protein-bound uraemic toxin that has deleterious effects on the cardiovascular system. Rosiglitazone (RGZ) is an insulin sensitizer used for glycaemic control in type 2 diabetes. Rosiglitazone has been shown to be beneficial for cardiovascular disease because of its pleiotropic effects. Whether RGZ can improve indoxyl sulphate-induced endothelial damage has not been investigated. In the present in vitro study, we examined the effects of RGZ on indoxyl sulphate-induced endothelial injury. Endothelial cells were exposed to RGZ (5 and 10 μmol/L) and then treated with indoxyl sulphate (100 and 1000 μmol/L) for 48 h. Indoxyl sulphate upregulated intracellular cell adhesion molecule-1, vascular cell adhesion molecule-1 and monocyte chemotactic protein-1 expression. Indoxyl sulphate also increased the abundance of NADPH oxidase 4 (NOX4) and nuclear factor (NF)-κB. Both extracellular signal-regulated kinase (ERK) 1/2 and p38 mitogen-activated protein kinase (MAPK) signalling pathways were activated after 48 h treatment with indoxyl sulphate. Pretreatment of cells with both concentrations of RGZ improved indices of endothelial injury. In addition, RGZ attenuated the increase in NOX4 and NF-κB and prevented the activation of the ERK1/2 and p38 MAPK signalling pathways. We conclude that RGZ ameliorates indoxyl sulphate-induced endothelial injury.

Airway epithelial cell PPARγ modulates cigarette smoke-induced chemokine expression and emphysema susceptibility in mice

Chronic obstructive pulmonary disease (COPD) is a highly prevalent, chronic inflammatory lung disease with limited existing therapeutic options. While modulation of peroxisome proliferator-activating receptor (PPAR)-γ activity can modify inflammatory responses in several models of lung injury, the relevance of the PPARG pathway in COPD pathogenesis has not been previously explored. Mice lacking Pparg specifically in airway epithelial cells displayed increased susceptibility to chronic cigarette smoke (CS)-induced emphysema, with excessive macrophage accumulation associated with increased expression of chemokines, Ccl5, Cxcl10, and Cxcl15. Conversely, treatment of mice with a pharmacological PPARγ activator attenuated Cxcl10 and Cxcl15 expression and macrophage accumulation in response to CS. In vitro, CS increased lung epithelial cell chemokine expression in a PPARγ activation-dependent fashion. The ability of PPARγ to regulate CS-induced chemokine expression in vitro was not specifically associated with peroxisome proliferator response element (PPRE)-mediated transactivation activity but was correlated with PPARγ-mediated transrepression of NF-κB activity. Pharmacological or genetic activation of PPARγ activity abrogated CS-dependent induction of NF-κB activity. Regulation of NF-κB activity involved direct PPARγ-NF-κB interaction and PPARγ-mediated effects on IKK activation, IκBα degradation, and nuclear translocation of p65. Our data indicate that PPARG represents a disease-relevant pathophysiological and pharmacological target in COPD. Its activation state likely contributes to NF-κB-dependent, CS-induced chemokine-mediated regulation of inflammatory cell accumulation.

Vetiver oil (Java) attenuates cisplatin-induced oxidative stress, nephrotoxicity and myelosuppression in Swiss albino mice

Clinical efficacy of the widely used anticancer drug cisplatin is limited due to its adverse side effects in normal tissues mediated by oxidative stress. This study was aimed to investigate the protective effects of vetiver acetate oil, Java (VO) against cisplatin-induced toxicity in Swiss albino mice. The ameliorating potential was evaluated by orally priming the animals with VO at doses 5, 10 or 20 mg/kg bw for 7 days prior to cisplatin treatment. Acute toxicity in mice was induced by injecting cisplatin (3 mg/kg bw) intraperitoneally for 5 consecutive days. Significant attenuation of renal toxicity was confirmed by histopathological examination, lowered levels of serum blood urea nitrogen, creatinine and reduced DNA damage. VO also compensated deficits in the renal antioxidant system. VO intervention significantly inhibited DNA damage, clastogenic effects, and cell cycle arrest in the bone marrow cells of mice. Hematological parameters indicated attenuation of cisplatin-induced myelosuppression. Overall, this study provides for the first time that VO has a protective role in the abatement of cisplatin-induced toxicity in mice which may be attributed to its antioxidant activity.

Recombinant human erythropoietin pretreatment attenuates acute renal tubular injury against ischemia-reperfusion by restoring transient receptor potential channel-6 expression and function in collecting ducts

OBJECTIVE

Acute renal tubular injury is a serious complication in the postoperative period, which is associated with high mortality and increased ICU stay. We aimed to demonstrate the protective effect of rhEPO against acute tubular injury induced by ischemia-reperfusion and to explore the mechanism of canonical transient receptor potential channel-6.

DESIGN

Randomized laboratory animal study.

SETTINGS

Animal research laboratory.

INTERVENTIONS

Male Sprague-Dawley rats were randomly divided into three groups: the sham group, the control group, and the rhEPO group. Experimental acute tubular injury was established in rats by bilateral renal arterial occlusion for 30 minutes followed by reperfusion.

MEASUREMENTS AND MAIN RESULTS

Blood samples were obtained for cystatin-C and neutrophil gelatinase-associated lipocalin measurements by enzyme-linked immunosorbance assays. Seventy-two hours after reperfusion, urine samples were collected for osmolality and fractional excretion of sodium (%) assays on a chemistry analyzer. Kidneys were harvested at 24, 48, and 72 hours after reperfusion. Transient receptor potential channel-6, aquaporin-2, and Na,K-ATPase expression in collecting ducts were studied by immunofluorescence and Western blot. Coimmunoprecipitations were also performed to identify the possible signalplex relation between transient receptor potential channel-6 and aquaporin-2 or Na,K-ATPase channels. RhEPO pretreatment significantly inhibited serum cystatin-C (2 hr: 453 ± 64 μg/L vs 337 ± 28 μg/L, p < 0.01), serum neutrophil gelatinase-associated lipocalin (72 hr: 1,175 ± 107 ng/L vs 1,737 ± 402 ng/L, p < 0.05), and urinary fractional excretion of sodium (%) increase (0.9 ± 0.1 vs 2.2 ± 0.8, p < 0.05) and alleviated the decrease of urinary osmolality (1,293 ± 101 mosmol/kg H2O vs 767 ± 91 mosmol/kg H2O, p < 0.05) induced by ischemia-reperfusion injury. Meanwhile, recombinant human erythropoietin greatly improved the ischemia-reperfusion-induced attenuation of transient receptor potential channel-6 expression (48 hr: 42% ± 2% vs 67% ± 2% and 72 hr: 55% ± 2% vs 66% ± 2%), as well as aquaporin-2 and Na,K-ATPase expression in collecting ducts. Transient receptor potential channel-6 functionally interacted with Na,K-ATPase but not aquaporin-2.

CONCLUSIONS

Recombinant human erythropoietin pretreatment at the dose of 5,000 IU/kg potently prevented ischemia-reperfusion-induced acute tubular injury, which might be partly attributed to the restoring the effect of transient receptor potential channel-6 expression and collecting duct function.

P2X7 receptor blockade protects against cisplatin-induced nephrotoxicity in mice by decreasing the activities of inflammasome components, oxidative stress and caspase-3

Nephrotoxicity is a common complication of cisplatin chemotherapy and thus limits the use of cisplatin in clinic. The purinergic 2X7 receptor (P2X7R) plays important roles in inflammation and apoptosis in some inflammatory diseases; however, its roles in cisplatin-induced nephrotoxicity remain unclear. In this study, we first assessed the expression of P2X7R in cisplatin-induced nephrotoxicity in C57BL/6 mice, and then we investigated the changes of renal function, histological injury, inflammatory response, and apoptosis in renal tissues after P2X7R blockade in vivo using an antagonist A-438079. Moreover, we measured the changes of nod-like receptor family, pyrin domain containing proteins (NLRP3) inflammasome components, oxidative stress, and proapoptotic genes in renal tissues in cisplatin-induced nephrotoxicity after treatment with A-438079. We found that the expression of P2X7R was significantly upregulated in the renal tubular epithelial cells in cisplatin-induced nephrotoxicity compared with that of the normal control group. Furthermore, pretreatment with A-438079 markedly attenuated the cisplatin-induced renal injury while lightening the histological damage, inflammatory response and apoptosis in renal tissue, and improved the renal function. These effects were associated with the significantly reduced levels of NLRP3 inflammasome components, oxidative stress, p53 and caspase-3 in renal tissues in cisplatin-induced nephrotoxicity. In conclusions, our studies suggest that the upregulated activity of P2X7R might play important roles in the development of cisplatin-induced nephrotoxicity, and P2X7R blockade might become an effective therapeutic strategy for this disease.

Pathophysiology of cisplatin-induced acute kidney injury

Cisplatin and other platinum derivatives are the most widely used chemotherapeutic agents to treat solid tumors including ovarian, head and neck, and testicular germ cell tumors. A known complication of cisplatin administration is acute kidney injury (AKI). The nephrotoxic effect of cisplatin is cumulative and dose-dependent and often necessitates dose reduction or withdrawal. Recurrent episodes of AKI may result in chronic kidney disease. The pathophysiology of cisplatin-induced AKI involves proximal tubular injury, oxidative stress, inflammation, and vascular injury in the kidney. There is predominantly acute tubular necrosis and also apoptosis in the proximal tubules. There is activation of multiple proinflammatory cytokines and infiltration of inflammatory cells in the kidney. Inhibition of the proinflammatory cytokines TNF-α or IL-33 or depletion of CD4+ T cells or mast cells protects against cisplatin-induced AKI. Cisplatin also causes endothelial cell injury. An understanding of the pathogenesis of cisplatin-induced AKI is important for the development of adjunctive therapies to prevent AKI, to lessen the need for dose decrease or drug withdrawal, and to lessen patient morbidity and mortality.

Activation of G-protein-coupled receptor 40 attenuates the cisplatin-induced apoptosis of human renal proximal tubule epithelial cells

G-protein-coupled receptor 40 (GPR40) is known to play a role in the regulation of fatty acids, insulin secretion and inflammation. However, the pathophysiological roles of GPR40 in kidney disease have not yet been identified. In the present study, we investigated the expression of GPR40 during cisplatin-induced kidney injury using male Sprague-Dawley rats that were treated with 8 mg/kg cisplatin. Control rats were treated with saline. Following treatment with cisplatin, the protein expression of GPR40 in the kidneys was decreased in association with an increase in serum creatinine levels and the Bax/Bcl-2 expression ratio. To further investigate the function of GPR40, the human renal proximal tubule epithelial cell line (HK-2) was cultured with cisplatin in the absence or presence of GW9508, a selective GPR40 agonist. Pre-treatment of the HK-2 cells with GW9508 attenuated the decrease in cell viability induced by treatment with cisplatin. Treatment with cisplatin increased the number of cells with condensed nuclei, which was ameliorated by GW9508 pre-treatment. TUNEL assay also revealed that pre-treatment with GW9508 ameliorated cisplatin-induced apoptosis. Treatment with cisplatin increased the Bax/Bcl-2 expression ratio and cleaved caspase-3 expression, and promoted the activation of nuclear factor-κB (NF-κB). These changes were attenuated by pre-treatment with GW9508. The cisplatin-induced generation of reactive oxygen species (ROS) and the activation of the Src/epidermal growth factor receptor (EGFR)/extracellular signal-regulated kinase (ERK) pathway were also counteracted by pre-treatment with GW9508. Thus, the activation of GPR40 attenuates cisplatin-induced apoptosis by inhibiting the generation of ROS, the activation of the Src/EGFR/ERK signaling pathway and the nuclear activation of NF-κB and pro-apoptotic factors.

Protective effect of metalloporphyrins against cisplatin-induced kidney injury in mice

Oxidative and nitrative stress is a well-known phenomenon in cisplatin-induced nephrotoxicity. The purpose of this work is to study the role of two metalloporphyrins (FeTMPyP and MnTBAP), water soluble complexes, in cisplatin-induced renal damage and their ability to scavenge peroxynitrite. In cisplatin-induced nephropathy study in mice, renal nitrative stress was evident by the increase in protein nitration. Cisplatin-induced nephrotoxicity was also evident by the histological damage from the loss of the proximal tubular brush border, blebbing of apical membranes, tubular epithelial cell detachment from the basement membrane, or intra-luminal aggregation of cells and proteins and by the increase in blood urea nitrogen and serum creatinine. Cisplatin-induced apoptosis and cell death as shown by Caspase 3 assessments, TUNEL staining and DNA fragmentation Cisplatin-induced nitrative stress, apoptosis and nephrotoxicity were attenuated by both metalloporphyrins. Heme oxygenase (HO-1) also plays a critical role in metalloporphyrin-mediated protection of cisplatin-induced nephrotoxicity. It is evident that nitrative stress plays a critical role in cisplatin-induced nephrotoxicity in mice. Our data suggest that peroxynitrite is involved, at least in part, in cisplatin-induced nephrotoxicity and protein nitration and cisplatin-induced nephrotoxicity can be prevented with the use of metalloporphyrins.

SUMOylation of PPARγ by rosiglitazone prevents LPS-induced NCoR degradation mediating down regulation of chemokines expression in renal proximal tubular cells

Rosiglitazone (RGL), a synthetic agonist for peroxisome proliferator activated receptor γ (PPARγ), exhibits a potent anti-inflammatory activity by attenuating local infiltration of neutrophils and monocytes in the renal interstitium. To evaluate the mechanisms that account for inhibiting inflammatory cells infiltration, we investigated the effect of RGL on chemokines secretion and nuclear factor-kappa B (NF-κB) activation in human renal proximal tubular cells (PTCs). We demonstrated that RGL significantly inhibited lipopolysaccharide (LPS)-induced interleukin-8 (IL-8) and monocyte chemoattractant protein-1 (MCP-1) production in a dose-dependent manner, without appreciable cytotoxicity. Chromatin immunoprecipitation (ChIP) assays clearly revealed that, RGL inhibited p65 binding to IL-8/MCP-1 gene promoters in LPS-stimulated PTCs. Interestingly, further experiments showed RGL reversed LPS-induced nuclear receptor corepressor (NCoR) degradation. In addition, knockdown of protein inhibitor of activated STAT1 (PIAS1), an indispensable small ubiquitin-like modifier (SUMO) ligase, abrogated the effects of RGL on antagonizing LPS-induced IL-8/MCP-1 overexpression and NCoR degradation. These findings suggest that, RGL activates PPARγ SUMOylation, inhibiting NCoR degradation and NF-κB activation in LPS-stimulated PTCs, which in turn decrease chemokines expression. The results unveil a new mechanism triggered by RGL for prevention of tubular inflammatory injury.

Disparity in actions of rosiglitazone against cisplatin-induced nephrotoxicity in female Sprague-Dawley rats

Cisplatin is one of the most common chemotherapeutic drugs used against various solid, tumours. Despite of its therapeutic benefits, its use in clinical practice is often limited because of dose, related toxicity. The nephrotoxic potential of cisplatin has been ascribed to its accumulation in the, renal tubular cells generating reactive oxygen species (ROS), activation of Bax, increased secretion of, TNFα and activation of certain inflammatory mediators like cytokines. The present investigation was, undertaken with an objective to study the effect of rosiglitazone against cisplatin induced, nephrotoxicity. Pretreatment of rosiglitazone prevents cisplatin induced nephrotoxicity which was, clearly evident from the renal biochemical parameters like reduced BUN, creatinine and TNFα levels, and increased albumin levels, which was also supported by histopathological studies of the kidneys. In contrast, posttreatment of rosiglitazone was not able to protect the renal damage in cisplatin induced, renal toxicity. These results showed the variation of pre & posttreatment effects of rosiglitazone, against the cisplatin induced nephrotoxicity.

Pharmacological activation of NQO1 increases NAD⁺ levels and attenuates cisplatin-mediated acute kidney injury in mice

Cisplatin is a widely used chemotherapeutic agent for the treatment of various tumors. In addition to its antitumor activity, cisplatin affects normal cells and may induce adverse effects, such as ototoxicity, nephrotoxicity, and neuropathy. Various mechanisms, such as DNA adduct formation, mitochondrial dysfunction, oxidative stress, and inflammatory responses, are critically involved in cisplatin-induced adverse effects. As NAD⁺ is a cofactor for various enzymes associated with cellular homeostasis, we studied the effects of increased NAD⁺ levels by means of NAD(P)H:quinone oxidoreductase 1 (NQO1) activation using a known pharmacological activator (β-lapachone) in wild-type and NQO1^−/− mice on cisplatin-induced renal dysfunction in vivo. The intracellular NAD⁺/NADH ratio in renal tissues was significantly increased in wild-type mice co-treated with cisplatin and β-lapachone compared with the ratio in mice treated with cisplatin alone. Inflammatory cytokines and biochemical markers for renal damage were significantly attenuated by β-lapachone co-treatment compared with those in the cisplatin alone group. Notably, the protective effects of β-lapachone in wild-type mice were completely abrogated in NQO1^−/− mice. Moreover, β-lapachone enhanced the tumoricidal action of cisplatin in a xenograft tumor model. Thus, intracellular regulation of NAD⁺ levels through NQO1 activation might be a promising therapeutic target for the protection of cisplatin-induced acute kidney injury.

Signalling mechanisms involved in renal pathological changes during cisplatin-induced nephropathy

CONTEXT

Cisplatin, a coordination platinum complex, is used as a potential anti-neoplastic agent, having well recognized DNA-damaging property that triggers cell-cycle arrest and cell death in cancer therapy. Beneficial chemotherapeutic actions of cisplatin can be detrimental for kidneys.

BACKGROUND

Unbound cisplatin gets accumulated in renal tubular cells, leading to cell injury and death. This liable action of cisplatin on kidneys is mediated by altered intracellular signalling pathways such as mitogen-activated protein kinase (MAPK), extracellular regulated kinase (ERK), or C- Jun N terminal kinase/stress-activated protein kinase (JNK/SAPK). Further, these signalling alterations are responsible for release and activation of tumour necrosis factor (TNF-α), mitochondrial dysfunction, and apoptosis, which ultimately cause the renal pathogenic process. Cisplatin itself enhances the generation of reactive oxygen species (ROS) and activation of nuclear factor-κB (NF-κB), inflammation, and mitochondrial dysfunction, which further leads to renal apoptosis. Cisplatin-induced nephropathy is also mediated through the p53 and protein kinase-Cδ (PKCδ) signalling pathways.

OBJECTIVE

This review explores these signalling alterations and their possible role in the pathogenesis of cisplatin-induced renal injury.

Luteolin ameliorates cisplatin-induced nephrotoxicity in mice through inhibition of platinum accumulation, inflammation and apoptosis in the kidney

The aim of this study was to investigate the effects of flavone luteolin against cisplatin (CP)-induced kidney injury in mice. Luteolin at doses of 10mg/kg was administered intraperitoneally (ip) once daily for 3 days following single CP (10 or 20mg/kg) ip injection. Mice were sacrificed 24h after the last dose of luteolin. The CP treatment significantly increased serum creatinine and blood urea nitrogen and induced pathohistological changes in the kidneys. Renal oxidative/nitrosative stress was evidenced by decreased glutathione (GSH) levels and increased 3-nitrotyrosine (3-NT) and 4-hydroxynonenal (4-HNE) formation as well as cytochrome P450 2E1 (CYP2E1) expression. The CP administration triggered inflammatory response in mice kidneys through activation of nuclear factor-kappaB (NF-κB) and overexpression of tumor necrosis factor-alpha (TNF-α) and cyclooxygenase-2 (COX-2). Simultaneously, the increase in renal p53 and caspase-3 expression indicated apoptosis of tubular cells. The administration of luteolin significantly reduced histological and biochemical changes induced by CP, decreased platinum (Pt) levels and suppressed oxidative/nitrosative stress, inflammation and apoptosis in the kidneys. These results suggest that luteolin is an effective nephroprotective agent, with potential to reduce Pt accumulation in the kidneys and ameliorate CP-induced nephrotoxicity.

Amelioration of cisplatin-induced mouse renal lesions by a cyclooxygenase (COX)-2 selective inhibitor

In this study, we investigated the effects of the cyclooxygenase (COX)-2 selective inhibitor, meloxicam, on cisplatin-induced inflammation, oxidative stress and renal lesions in BALB/c mice. A single cisplatin injection (13 mg/kg, i.p.) significantly increased plasma creatinine, blood urea nitrogen and urinary glucose accompanied by a concomitant increase in COX-2 mRNA and COX-2 protein levels. These changes in renal lesion parameters were diminished by simultaneous treatment of meloxicam (0.7 mg/kg/day in drinking water). The expression of oxidative stress markers, p47(phox), p67(phox), hemoxygenase-1 (HO-1), nicotinamide adenine dinucleotide phosphate (NADPH) oxidase 2 (NOX2) and 4-hydroxy-2-nonenal (4-HNE)-modified protein were increased with cisplatin injection. Simultaneous treatment of meloxicam with cisplatin significantly inhibited the increase in p47(phox), HO-1 and 4-HNE-modified protein. The phosphorylation of extracellular regulated kinase (ERK) and c-jun-N-terminal kinase (JNK) were increased with cisplatin injection, but these changes were inhibited by meloxicam. Moreover, concomitant meloxicam treatment also prevented the cisplatin-induced infiltration of macrophages to the tubulointerstitial area. These results suggest that meloxicam can ameliorate cisplatin-induced mouse renal lesions, potentially through the inhibition of inflammatory and oxidative stress responses.

Pathogenic and protective role of macrophages in kidney disease

Macrophages (MΦ) are located throughout kidney tissue, where they play important roles in homeostasis, surveillance, tolerance, and cytoprotection. MΦ are highly heterogeneous cells and exhibit distinct phenotypic and functional characteristics depending on their microenvironment and the disease type and stage. Recent studies have identified a dual role for MΦ in several murine models of kidney disease. In this review, we discuss the pathogenic and protective roles of the various MΦ subsets in experimental and human kidney diseases and summarize current progress toward the therapeutic use of MΦ in kidney diseases.

Renoprotective effect of pioglitazone by the prevention of glomerular hyperfiltration through the possible restoration of altered macula densa signaling in rats with type 2 diabetic nephropathy

BACKGROUND/AIMS

Pioglitazone (PGZ), one of the thiazolidinediones, has been known to show renoprotective effects. In this study, we focused on the effect of PGZ on glomerular hyperfiltration (GHF), resultant glomerular injury and altered macula densa signaling as a cause of sustained GHF through modified tubuloglomerular feedback in rats with diabetic nephropathy.

METHODS

Kidneys from 24-week-old male OLETF rats and LET rats, nondiabetic controls, were used for the experiment. PGZ was administered (10 mg/kg/day, p.o.) for 2 weeks from 22 to 24 weeks of age in some of the OLETF rats (OLETF+PGZ).

RESULTS

Parameters relating GHF, kidney weight, creatinine clearance, urine albumin/creatinine ratio and glomerular surface were all increased in OLETF rats and partially restored in OLETF+PGZ rats. Expressions of desmin and TGF-β were also increased in OLETF rats and restored in OLETF+PGZ rats. The changes in TGF-β expression were confirmed to be independent of podocyte number. Finally, the immunoreactivity of neuronal nitric oxide synthase (nNOS) and cyclooxygenase 2 (COX-2) in the macula densa was assessed for the evaluation of macula densa signaling. Altered intensities of nNOS and COX-2 in OLETF rats were restored in OLETF+PGZ rats, which agreed with the gene expression analysis (nNOS: 100.2 ± 2.9% in LET, 64.2 ± 2.7% in OLETF, 87.4 ± 12.1% in OLETF+PGZ; COX-2: 100.8 ± 7.4% in LET, 249.2 ± 19.4% in OLETF, 179.9 ± 13.5% in OLETF+PGZ; n = 5) and the semiquantitative analysis of nNOS/COX-2-positive cells.

CONCLUSION

PGZ effectively attenuated the GHF and hyperfiltration-associated glomerular injury in diabetic nephropathy. The restoration of altered macula densa signaling might be involved in the renoprotective effect of PGZ.

Growth inhibition effect of peptide P110 plus cisplatin on various cancer cells and xenotransplanted tumors in mice

The combined use of currently used anticancer genotoxins with other drugs is a therapeutic tool for potentially increasing the efficacy of the genotoxins. In the present study, the effects of a RasGAP-derived peptide, P110 (RasGAP301-316), designed to target Ras-GTPase activating protein SH3 domain-binding proteins (G3BPs), on the chemotherapeutic agent, cisplatin (DDP), were examined. P110 was demonstrated to enhance the effect of DPP in vitro and in vivo. The results indicate that P110 significantly increased the DDP-induced apoptosis in SGC-7901, HCT-116, HeLa and A-549 cells. Furthermore, P110 combined with DDP significantly suppressed the growth of C26 xenograft tumors in a dose-dependent manner. This synergistic effect may be associated with DDP-induced apoptosis, involving the downregulation of Bcl-2 and the upregulation of Bax, cytochrome c and caspase-3. The results of the present study indicate that P110, in combination with chemotherapeutics, is likely to represent a potential therapeutic strategy for cancer.

Attenuation of cisplatin-induced renal injury by inhibition of soluble epoxide hydrolase involves nuclear factor κB signaling

Acute kidney injury is associated with a significant inflammatory response that has been the target of renoprotection strategies. Epoxyeicosatrienoic acids (EETs) are anti-inflammatory cytochrome P450-derived eicosanoids that are abundantly produced in the kidney and metabolized by soluble epoxide hydrolase (sEH; Ephx2) to less active dihydroxyeicosatrienoic acids. Genetic disruption of Ephx2 and chemical inhibition of sEH were used to test whether the anti-inflammatory effects of EETs, and other lipid epoxide substrates of sEH, afford protection against cisplatin-induced nephrotoxicity. EET hydrolysis was significantly reduced in Ephx2(-/-) mice and was associated with an attenuation of cisplatin-induced increases in serum urea nitrogen and creatinine levels. Histological evidence of renal tubular damage and neutrophil infiltration was also reduced in the Ephx2(-/-) mice. Likewise, cisplatin had no effect on renal function, neutrophil infiltration, or tubular structure and integrity in mice treated with the potent sEH inhibitor 1-adamantan-1-yl-3-(1-methylsulfonyl-piperidin-4-yl-urea) (AR9273). Consistent with the ability of EETs to interfere with nuclear factor-κB (NF-κB) signaling, the observed renoprotection was associated with attenuation of renal NF-κB activity and corresponding decreases in the expression of tumor necrosis factor (TNF) α, TNF receptor (TNFR) 1, TNFR2, and intercellular adhesive molecule-1 before the detection of tubular injury. These data suggest that EETs or other fatty acid epoxides can attenuate cisplatin-induced kidney injury and sEH inhibition is a novel renoprotective strategy.