Mitochondrial dysregulation and protection in cisplatin nephrotoxicity

Advances in understanding cisplatin-induced toxicity: Molecular mechanisms and protective strategies

Cisplatin, a widely used chemotherapeutic agent, has proven efficacy against various malignancies. However, its clinical utility is hampered by its dose-limiting toxicities, including nephrotoxicity, ototoxicity, neurotoxicity, and myelosuppression. This review aims to provide a comprehensive overview of cisplatin toxicity, encompassing its underlying mechanisms, risk factors, and emerging therapeutic strategies. The mechanisms of cisplatin toxicity are multifactorial and involve oxidative stress, inflammation, DNA damage, and cellular apoptosis. Various risk factors contribute to the interindividual variability in susceptibility to cisplatin toxicity. The risk of developing cisplatin-induced toxicity could be related to pre-existing conditions, including kidney disease, hearing impairment, neuropathy, impaired liver function, and other comorbidities. Additionally, this review highlights the emerging therapeutic strategies that could be applied to minimize cisplatin-induced toxicities and aid in optimizing cisplatin treatment regimens, improving patient outcomes, and enhancing the overall quality of cancer care.

Nephropathy induced by cisplatin results from mitochondrial disruption, impaired energy metabolism, altered expression of renal transporters, and accumulation of urinary toxins

BACKGROUND

The administration of platinum-based drugs such as cisplatin and its derivatives, which are frequently used during clinical chemotherapy, is highly restricted due to the incidence of nephrotoxicity. The present study focused on investigating cisplatin-induced nephrotoxicity from the perspective of energy metabolism, renal transporter expression and urinary toxin accumulation.

METHODS

This study investigated cisplatin's toxic effects, including nephrotoxicity, cardiotoxicity, hepatotoxicity, pulmonary toxicity, and splenotoxicity. We used transmission electron microscopy (TEM) and scanning electron microscopy (SEM) to characterize the accumulation of cisplatin in the kidney and the structure of renal mitochondria. The production of reactive oxygen species (ROS) induced by cisplatin in renal tubular epithelial cells was evaluated by in vitro experiments, and apoptosis of renal tubular epithelial cells and alterations to the renal microvasculature were assessed. Metabolites associated with the glycolytic and tricarboxylic acid pathways were measured, and renal transporters expression, autophagy, and urinary toxins (UTs) accumulation were also assessed.

RESULTS

Our results reveal that cisplatin-induced varying degrees of damage to the heart, liver, spleen, lungs, and kidneys, including inflammatory and fibrotic damage. Accumulation of cisplatin in renal mitochondria disrupted mitochondrial structure and mitochondrial function, as evidenced by decreased levels of glucose 6-phosphate and ribose 5-phosphate and elevated levels of isocitric acid. Cisplatin-induced accumulation of ROS in renal tubular epithelial cells led to apoptosis and, ultimately, constriction or loss of renal microvasculature. Furthermore, dysregulation of renal transporter expression, activation of autophagy and increased accumulation of UTs was observed.

CONCLUSION

Accumulation of cisplatin in the kidney led to damage to mitochondrial structure and function, apoptosis of renal tubular epithelial cells, constriction or loss of renal microvasculature, dysfunction of renal transporters, activation of autophagy, and accumulation of UTs.

Renal Glutathione: Dual roles as antioxidant protector and bioactivation promoter

The tripeptide glutathione (GSH) possesses two key structural features, namely the nucleophilic sulfur and the γ-glutamyl isopeptide bond. The former allows GSH to serve as a critical antioxidant and anti-electrophile. The latter allows GSH to translocate throughout the systemic circulation without being degraded. The kidneys exhibit several unique processes for handling GSH. This includes the extraction of 80% of plasma GSH, in part by glomerular filtration but mostly by transport across the basolateral plasma membrane. Studies on the protective effect of exogenous GSH are summarized, showing the different inherent susceptibility of proximal tubular and distal tubular cells and the impact on pathological or disease states, including hypoxia, diabetic nephropathy, and compensatory renal growth associated with uninephrectomy. Studies on mitochondrial GSH transport show the coordination between the citric acid cycle and oxidative phosphorylation in generating driving forces for both plasma membrane and mitochondrial carriers. The strong protective effects of increasing expression and activity of these carriers against oxidants and mitochondrial toxicants are summarized. Although GSH plays a cytoprotective role in most situations, two distinct exceptions to this are presented. In contrast to expectations, overexpression of the mitochondrial 2-oxoglutarate carrier markedly increased cell death from exposure to the nephrotoxic chemotherapeutic drug cisplatin (CDDP). Another key example of GSH serving a bioactivation role in the kidneys, rather than a detoxification role, is the metabolism of halogenated alkenes such as trichloroethylene (TCE). Although considerable research has gone into this topic, unanswered questions and emerging topics remain and are discussed.

The toxicity of cisplatin derives from effects on renal organic ion transporters expression and serum endogenous substance levels

Acute kidney injury (AKI) is a worldwide public health problem with high morbidity and mortality. Cisplatin is a widely used chemotherapeutic agent for treating solid tumors, but the induction of AKI restricts its clinical application. In this study, the effect of cisplatin on the expression of organic ion transporters was investigated through in vivo and in vitro experiments. Targeted metabolomics techniques were used to measure the levels of selected endogenous substances in serum. Transmission electron microscopy was used to observe the microstructure of renal tubular epithelial cells. Our results show that the toxicity of cisplatin on HK-2 cells or HEK-293 cells was time- and dose-dependent. Administration of cisplatin decreased the expression of OAT1/3 and OCT2 and increased the expression of MRP2/4. Mitochondrial damage induced by cisplatin lead to renal tubular epithelial cell injury. In addition, administration of cisplatin resulted in significant changes in endogenous substance levels in serum, including amino acids, carnitine, and fatty acids. These serum amino acids and metabolites (α-aminobutyric acid, proline, and alanine), carnitines (tradecanoylcarnitine, hexanylcarnitine, octanoylcarnitine, 2-methylbutyroylcarnitine, palmitoylcarnitine, and linoleylcarnitine) and fatty acids (9E-tetradecenoic acid) represent endogenous substances with diagnostic potential for cisplatin-induced AKI.

Synthesis and Biological Evaluation of Novel Psidium Meroterpenoid Derivatives against Cisplatin-Induced Acute Kidney Injury

Cisplatin is a widely used drug for the clinical treatment of tumors. However, nephrotoxicity limits its widespread use. A series of compounds including eight analogs (G3-G10) and 40 simplifiers (G11-G50) were synthesized based on the total synthesis of Psiguamer A and B, which were novel meroterpenoids with unusual skeletons from the leaves of Psidium guajava. Among these compounds, (d)-G8 showed the strongest protective effect on cisplatin-induced acute kidney injury (AKI) in vitro and vivo, and slightly enhanced the antitumor efficacy of cisplatin. A mechanistic study showed that (d)-G8 promoted the efflux of cisplatin via upregulating the copper transporting efflux proteins ATP7A and ATP7B. It enhanced autophagy through the activation of the adenosine monophosphate-activated protein kinase (AMPK) signaling pathway. (d)-G8 showed no acute toxicity or apparent pathological damage in the healthy mice at a single dose of 1 g/kg. This study provides a promising lead against cisplatin-induced AKI.

Efficacy of Trametinib in Alleviating Cisplatin-Induced Acute Kidney Injury: Inhibition of Inflammation, Oxidative Stress, and Tubular Cell Death in a Mouse Model

Cisplatin, a platinum-based chemotherapeutic, is effective against various solid tumors, but its use is often limited by its nephrotoxic effects. This study evaluated the protective effects of trametinib, an FDA-approved selective inhibitor of mitogen-activated protein kinase kinase 1/2 (MEK1/2), against cisplatin-induced acute kidney injury (AKI) in mice. The experimental design included four groups, control, trametinib, cisplatin, and a combination of cisplatin and trametinib, each consisting of eight mice. Cisplatin was administered intraperitoneally at a dose of 20 mg/kg to induce kidney injury, while trametinib was administered via oral gavage at 3 mg/kg daily for three days. Assessments were conducted 72 h after cisplatin administration. Our results demonstrate that trametinib significantly reduces the phosphorylation of MEK1/2 and extracellular signal-regulated kinase 1/2 (ERK1/2), mitigated renal dysfunction, and ameliorated histopathological abnormalities. Additionally, trametinib significantly decreased macrophage infiltration and the expression of pro-inflammatory cytokines in the kidneys. It also lowered lipid peroxidation by-products, restored the reduced glutathione/oxidized glutathione ratio, and downregulated NADPH oxidase 4. Furthermore, trametinib significantly inhibited both apoptosis and necroptosis in the kidneys. In conclusion, our data underscore the potential of trametinib as a therapeutic agent for cisplatin-induced AKI, highlighting its role in reducing inflammation, oxidative stress, and tubular cell death.

Identification of proteins related to SIS3 by iTRAQ and PRM-based comparative proteomic analysis in cisplatin-induced acute kidney injury

Background

Cisplatin is a commonly used nephrotoxic drug and can cause acute kidney injury (AKI). In the present study, isobaric tags for relative and absolute quantification (iTRAQ) and parallel reaction monitoring (PRM)-based comparative proteomics were used to analyze differentially expressed proteins (DEPs) to determine the key molecular mechanism in mice with cisplatin-induced AKI in the presence or absence of SIS3, a specific p-smad3 inhibitor, intervention.

Methods

The cisplatin-induced AKI mouse model was established and treated with SIS3. We used iTRAQ to search for DEPs, PRM to verify key DEPs and combined Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) for bioinformatics analysis. We then assessed lipid deposition, malondialdehyde (MDA) and reactive oxygen species (ROS) and detected the expression of SREBF1, SCD1, CPT1A, PPARα and NDRG1 in vitro.

Results

Proteomic analysis showed that the identified DEPs were mainly enriched in energy metabolism pathways, especially in lipid metabolism. When SIS3 was applied to inhibit the phosphorylation of Smad3, the expression of NDRG1 and fatty acid oxidation key proteins CPT1A and PPARα increased, the expression of lipid synthesis related proteins SREBF1 and SCD1 decreased and the production of lipid droplets, MDA and ROS decreased.

Conclusion

SIS3 alleviates oxidative stress, reduces lipid accumulation and promotes fatty acid oxidation through NDRG1 in cisplatin-induced AKI. Our study provides a new candidate protein for elucidating the molecular mechanisms of fatty acid metabolism disorders in cisplatin-induced acute kidney injury.

A combination of generated hydrogen sulfide and nitric oxide activity has a potentiated protectant effect against cisplatin induced nephrotoxicity

Aim

Hydrogen sulfide and nitric oxide possess cytoprotective activity and in vivo, they are generated from exogenous sodium hydrosulfide and L-arginine respectively. Cisplatin is a major chemotherapeutic agent used to treat cancer and has a high incidence of nephrotoxicity as a side effect. The study aim was to explore the effects of NaHS and L-arginine or their combination on cisplatin induced nephrotoxicity in rats.

Methods

Wistar Kyoto rats were given a single intraperitoneal dose of cisplatin (5 mg/kg) followed either by NaHS (56 μmol/kg, i. p.), L-arginine (1.25 g/L in drinking water) or their combination daily for 28-days. Post-mortem plasma, urine and kidney samples were collected for biochemical assays and histopathological analysis.

Results

Cisplatin decreased body weights and increased urinary output, while plasma creatinine and urea levels were elevated, but sodium and potassium concentrations were diminished. The renal function parameters, blood urea nitrogen and creatinine clearance, were raised and decreased respectively. Regarding markers of reactive oxygen species, plasma total superoxide dismutase was reduced, whereas malondiadehyde was augmented.Cisplatin also diminished plasma and urinary H2S as well as plasma NO, while NaHS and L-arginine counteracted this activity on both redox-active molecules. Cisplatin cotreatment with NaHS, and/or L-arginine exhibited a reversal of all other measured parameters.

Conclusion

In current study, NaHS and L-arginine as monotherapy protected the rats from cisplatin-induced nephrotoxicity but the combination of both worked more effectively suggesting the augmented anti-inflammatory and antioxidative potential of test treatments when administered together.

Indole-3-carboxaldehyde alleviates cisplatin-induced acute kidney injury in mice by improving mitochondrial dysfunction via PKA activation

Cisplatin (DDP) is widely used in the treatment of cancer as a chemotherapeutic drug. However, its severe nephrotoxicity limits the extensive application of cisplatin, which is characterized by injury and apoptosis of renal tubular epithelial cells. This study aimed to reveal the protective effect and its underlying mechanism of Indole-3-carboxaldehyde (IC) against DDP-induced AKI in mice and NRK-52E cells pretreated with PKA antagonist (H-89). Here, we reported that IC improved renal artery blood flow velocity and renal function related indicators, attenuated renal pathological changes, which were confirmed by the results of HE staining and PASM staining. Meanwhile, IC inhibited the levels of inflammatory factors, oxidative stress, CTR1, OCT2, and the levels of autophagy and apoptosis. Mitochondrial dysfunction was significantly improved as observed by TEM. To clarify the potential mechanism, NRK-52E cells induced by DDP was used and the results proved that H-89 could blocked the improvement with IC effectively in vitro. Our findings showed that IC has the potential to treat cisplatin-induced AKI, and its role in protecting the kidney was closely related to activating PKA, inhibiting autophagy and apoptosis, improving mitochondrial function, which could provide a theoretical basis for the development of new clinical drugs.

Sensitivity of Human Induced Pluripotent Stem Cells and Thereof Differentiated Kidney Proximal Tubular Cells towards Selected Nephrotoxins

Proximal tubular epithelial cells (PTEC) are constantly exposed to potentially toxic metabolites and xenobiotics. The regenerative potential of the kidney enables the replacement of damaged cells either via the differentiation of stem cells or the re-acquisition of proliferative properties of the PTEC. Nevertheless, it is known that renal function declines, suggesting that the deteriorated cells are not replaced by fully functional cells. To understand the possible causes of this loss of kidney cell function, it is crucial to understand the role of toxins during the regeneration process. Therefore, we investigated the sensitivity and function of human induced pluripotent stem cells (hiPSC), hiPSC differentiating, and hiPSC differentiated into proximal tubular epithelial-like cells (PTELC) to known nephrotoxins. hiPSC were differentiated into PTELC, which exhibited similar morphology to PTEC, expressed prototypical PTEC markers, and were able to undergo albumin endocytosis. When treated with two nephrotoxins, hiPSC and differentiating hiPSC were more sensitive to cisplatin than differentiated PTELC, whereas all stages were equally sensitive to cyclosporin A. Both toxins also had an inhibitory effect on albumin uptake. Our results suggest a high sensitivity of differentiating cells towards toxins, which could have an unfavorable effect on regenerative processes. To study this, our model of hiPSC differentiating into PTELC appears suitable.

The Role of Mitochondria in Phytochemically Mediated Disease Amelioration

Mitochondrial dysfunction may cause cell death, which has recently emerged as a cancer prevention and treatment strategy mediated by chemotherapy drugs or phytochemicals. However, most existing drugs cannot target cancerous cells and may adversely affect normal cells via side effects. Mounting studies have revealed that phytochemicals such as resveratrol could ameliorate various diseases with dysfunctional or damaged mitochondria. For instance, resveratrol can regulate mitophagy, inhibit oxidative stress and preserve membrane potential, induce mitochondrial biogenesis, balance mitochondrial fusion and fission, and enhance the functionality of the electron transport chain. However, there are only a few studies suggesting that phytochemicals could potentially protect against the cytotoxicity of some current cancer drugs, especially those that damage mitochondria. Besides, COVID-19 and long COVID have also been reported to be correlated to mitochondrial dysfunction. Curcumin has been reported bringing a positive impact on COVID-19 and long COVID. Therefore, in this study, the benefits of resveratrol and curcumin to be applied for cancer treatment/prevention and disease amelioration were reviewed. Besides, this review also provides some perspectives on phytochemicals to be considered as a treatment adjuvant for COVID-19 and long COVID by targeting mitochondrial rescue. Hopefully, this review can provide new insight into disease treatment with phytochemicals targeting mitochondria.

Augmented nephroprotective effect of liraglutide and rabeprazole via inhibition of OCT2 transporter in cisplatin-induced nephrotoxicity in rats

AIMS

Cisplatin, a widely used anticancer treatment, has a marked nephrotoxic effect. This nephrotoxic effect is linked to the triggering of oxidative stress, inflammation, activation of mitogen-activated protein kinase (MAPK) pathway as well as apoptosis. The purpose of the present research was to examine the possible ameliorative effect of liraglutide and/or rabeprazole on cisplatin-induced nephrotoxicity in rats and to underline the potential molecular pathways involved.

MAIN METHODS

Rats were divided into five groups: Control, cisplatin, liraglutide (200 μg/kg/day, i.p), rabeprazole (10 mg/kg/day, orally) and liraglutide + rabeprazole combination groups. All treatments were given for 7 days. Cisplatin was given as a single dose (7 mg/kg, i.p) at day 4 to induce nephrotoxicity in all groups except the control group.

KEY FINDINGS

Treatment with liraglutide and/or rabeprazole prior to cisplatin maintained the function and morphology of kidney via decreasing cisplatin renal uptake by significant inhibition of OCT2. Besides, they showed a significant increase in GLP-1 receptor expression. Liraglutide and/or rabeprazole significantly attenuated the levels of TNF-α. ICAM, NF-κB, and downregulated MAPK pathway proteins such as JNK, and ERK1/2. Moreover, they maintained oxidant antioxidant balance by decreasing MDA level and increasing GSH level and CAT activity. Additionally, liraglutide and/or rabeprazole exhibited antiapoptotic effect evidenced by the decreased caspase-3 level and Bax expression and the increased Bcl-2 expression.

SIGNIFICANCE

The current study showed that both liraglutide and rabeprazole exerted a nephroprotective effect against cisplatin-induced renal toxicity in rats. Interestingly, co-treatment with both drugs showed an augmented effect.

Degranulation of Murine Resident Cochlear Mast Cells: A Possible Factor Contributing to Cisplatin-Induced Ototoxicity and Neurotoxicity

Permanent hearing loss is one of cisplatin's adverse effects, affecting 30-60% of cancer patients treated with that drug. Our research group recently identified resident mast cells in rodents' cochleae and observed that the number of mast cells changed upon adding cisplatin to cochlear explants. Here, we followed that observation and found that the murine cochlear mast cells degranulate in response to cisplatin and that the mast cell stabilizer cromoglicic acid (cromolyn) inhibits this process. Additionally, cromolyn significantly prevented cisplatin-induced loss of auditory hair cells and spiral ganglion neurons. Our study provides the first evidence for the possible mast cell participation in cisplatin-induced damage to the inner ear.

Cobaltosic oxide-polyethylene glycol-triphenylphosphine nanoparticles ameliorate the acute-to-chronic kidney disease transition by inducing BNIP3-mediated mitophagy

Accumulating evidence highlights mitochondrial dysfunction as a crucial factor in the pathogenesis of acute kidney injury (AKI); thus, novel therapeutic strategies maintaining mitochondrial homeostasis are highly anticipated. Recent studies have shown that cobaltosic oxide has peroxidase-like catalytic activities, although its role and mechanism remain elusive in AKI. In the present study, we synthesized and identified cobaltosic oxide-polyethylene glycol-triphenylphosphine (COPT) nanoparticles by conjugating cobaltosic oxide with polyethylene glycol and triphenylphosphine, to improve its biocompatibility and mitochondria-targeting property. We found that COPT preferentially accumulated in the kidney proximal tubule cells, and significantly alleviated ischemic AKI in mouse models and gentamicin induced-AKI in the zebrafish model. COPT also inhibited the transition from AKI to chronic kidney disease (CKD), with few side effects. Further studies demonstrated that COPT localized in the mitochondria, and ameliorated hypoxia-reoxygenation-mediated mitochondrial damage through enhancing mitophagy in vitro and in vivo. Mechanistically, COPT dose-dependently induced the expression of Bcl-2/adenovirus E1B 19-kDa interacting protein (BNIP3), while knockdown of BNIP3 attenuated COPT-induced mitophagic flux and mitochondrial protection. Thus, our findings suggest that COPT nanoparticles ameliorate AKI and its progression to CKD through inducing BNIP3-mediated mitophagy, indicating that COPT may serve as a promising mitochondria-targeting therapeutic agent against AKI.

Role of Transcription Factor EB in Mitochondrial Dysfunction of Cisplatin-Induced Acute Kidney Injury

Cisplatin, a widely used anticancer agent, can cause nephrotoxicity, including both acute kidney injury (AKI) and chronic kidney diseases, by accumulating in renal tubular epithelial cells (TECs). Mitochondrial pathology plays an important role in the pathogenesis of AKI. Based on the regulatory role of transcription factor EB (TFEB) in mitochondria, we investigated whether TFEB is involved in cisplatin-induced TEC damage. The results show that the expression of TFEB decreased in a concentration-dependent manner in both mouse kidney tissue and HK-2 cells when treated with cisplatin. A knockdown of TFEB aggravated cisplatin-induced renal TEC injury, which was partially reversed by TFEB overexpression in HK-2 cells. It was further observed that the TFEB knockdown also exacerbated cisplatin-induced mitochondrial damage in vitro, and included the depolarization of membrane potential, mitochondrial fragmentation and swelling, and the production of reactive oxygen species. In contrast, TFEB overexpression alleviated cisplatin-induced mitochondrial damage in TECs. These findings suggest that decreased TFEB expression may be a key mechanism of mitochondrial dysfunction in cisplatin-induced AKI, and that upregulation of TFEB has the potential to act as a therapeutic target to alleviate mitochondrial dysfunction and cisplatin-induced TEC injury. This study is important for developing therapeutic strategies to manipulate mitochondria through TFEB to delay AKI progression.

A novel 3-phenylglutaric acid derivative (84-B10) alleviates cisplatin-induced acute kidney injury by inhibiting mitochondrial oxidative stress-mediated ferroptosis

Cisplatin is one of the most effective chemotherapy drugs and is widely used for cancer treatment. However, its clinical use is limited by nephrotoxicity. Emerging findings suggested that both ferroptosis and mitochondrial dysfunction mediate cisplatin-induced nephrotoxicity. In the current study, a novel 3-phenylglutaric acid derivative 5-[[2-(4-methoxyphenoxy)-5-(trifluoromethyl)phenyl]amino]-5-oxo-3-phenylpentanoic acid (referred to as 84-B10) was found to play a protective role in cisplatin-induced acute kidney injury with no tumor promoting effects. A genome-wide transcriptome analysis indicated that the protective effect of 84-B10 might be dependent on antagonizing ferroptosis. In accordance, lipid peroxide accumulation and downregulation of key ferroptosis suppressors were reversed using 84-B10 treatment both in vivo and in vitro. In addition, 84-B10 inhibited cisplatin-induced mitochondrial damage and mitochondrial reactive oxygen species (mtROS) production and restored superoxide dismutases (SODs). Furthermore, 84-B10 showed similar therapeutic effects to MnTBAP (a cell-permeable SOD mimetic) in eliminating mtROS, restoring mitochondrial homeostasis, and inhibiting ferroptosis under cisplatin challenge. Comparable effects of 84-B10 and liproxstatin-1 in ameliorating cisplatin-induced ferroptosis were observed. However, liproxstatin-1 failed to prevent mitochondrial dysfunction. These data indicated that mtROS might act upstream of cisplatin-induced tubular ferroptosis. Taken together, the novel 3-phenylglutaric acid derivative 84-B10 showed therapeutic potential against cisplatin-induced nephrotoxicity possibly by restoring mitochondria homeostasis and inhibiting mtROS-induced ferroptosis, which suggests the potential use of 84-B10 in preventing and treating cisplatin-nephrotoxicity.

The diminution and modulation role of water-soluble gallic acid-carboxymethyl chitosan conjugates against the induced nephrotoxicity with cisplatin

The toxicity of cisplatin (CDDP) toward the renal tubules and its severe effects on the proximal tubules limits its further use in cancer therapy. The current study was undertaken to evaluate the protective effects of gallic acid-grafted O-carboxymethyl chitosan (GA@CMCS) against nephrotoxicity induced by CDDP in rats. Renal injury was assessed in the GA@CMCS/CDDP-treated rats using kidney injury molecule-1 (KIM-1). Moreover, the levels of reduced glutathione (GSH), malondialdehyde (MDA), and nitric oxide (NO) were measured. The comet assay was performed to measure the DNA damage. The renoprotective activity of GA@CMCS was supported by histo- and immuno-pathological studies of the kidney. GA@CMCS significantly normalized the increases in kidney homogenate of KIM-1, MDA, and NO-induced by CDDP and significantly increased GSH as compared with the CDDP group. GA@CMCS also significantly protects rat kidneys from CDDP-induced histo- and immuno-pathological changes. Both biochemical findings and histo- and immuno-pathological evidence showed the renoprotective potential of GA@CMCS against CDDP-induced oxidative stress, inflammation, and renal dysfunction in rats. In conclusion, GA@CMCS has been shown to mitigate the nephrotoxicity impact of CDDP in cancer therapy.

Protective Effect of Natural Antioxidants on Reducing Cisplatin-Induced Nephrotoxicity

The clinical application of cisplatin is limited by its adverse events, of which nephrotoxicity is the most commonly observed. In a cisplatin-induced pathological response, oxidative stress is one of the upstream reactions which inflicts different degrees of damages to the intracellular material components. Reactive oxygen species (ROS) are also one of the early signaling molecules that subsequently undergo a series of pathological reactions, such as apoptosis and necrosis. This review summarizes the mechanism of intracellular ROS generation induced by cisplatin, mainly from the consumption of endogenous antioxidants, destruction of antioxidant enzymes, induction of mitochondrial crosstalk between the endoplasmic reticulum by ROS and Ca²⁺, and destruction of the cytochrome P450 (CYP) system in the endoplasmic reticulum, all of which result in excessive accumulation of intracellular ROS and oxidative stress. In addition, studies demonstrated that natural antioxidants can protect against the cisplatin-induced nephrotoxicity, by reducing or even eliminating excess free radicals and also affecting other nonredox pathways. Therefore, this review on the one hand provides theoretical support for the research and clinical application of natural antioxidants and on the other hand provides a new entry point for the detailed mechanism of cisplatin nephrotoxicity, which may lay a solid foundation for the future clinical use of cisplatin.

Magnesium Isoglycyrrhizinate Reduces the Target-Binding Amount of Cisplatin to Mitochondrial DNA and Renal Injury through SIRT3

Nephrotoxicity is the dose-limiting factor of cisplatin treatment. Magnesium isoglycyrrhizinate (MgIG) has been reported to ameliorate renal ischemia–reperfusion injury. This study aimed to investigate the protective effect and possible mechanisms of MgIG against cisplatin-induced nephrotoxicity from the perspective of cellular pharmacokinetics. We found that cisplatin predominantly accumulated in mitochondria of renal tubular epithelial cells, and the amount of binding with mitochondrial DNA (mtDNA) was more than twice that with nuclear DNA (nDNA). MgIG significantly lowered the accumulation of cisplatin in mitochondria and, in particular, the degree of target-binding to mtDNA. MgIG notably ameliorated cisplatin-induced changes in mitochondrial membrane potential, morphology, function, and cell viability, while the magnesium donor drugs failed to work. In a mouse model, MgIG significantly alleviated cisplatin-caused renal dysfunction, pathological changes of renal tubules, mitochondrial ultrastructure variations, and disturbed energy metabolism. Both in vitro and in vivo data showed that MgIG recovered the reduction of NAD+-related substances and NAD+-dependent deacetylase sirtuin-3 (SIRT3) level caused by cisplatin. Furthermore, SIRT3 knockdown weakened the protective effect of MgIG on mitochondria, while SIRT3 agonist protected HK-2 cells from cisplatin and specifically reduced platinum-binding activity with mtDNA. In conclusion, MgIG reduces the target-binding amount of platinum to mtDNA and exerts a protective effect on cisplatin-induced renal injury through SIRT3, which may provide a new strategy for the treatment of cisplatin-induced nephrotoxicity.

Mitochondrial Targeted Antioxidant SKQ1 Ameliorates Acute Kidney Injury by Inhibiting Ferroptosis

Emerging evidence suggests that ferroptosis is highly correlated with the pathogenesis of acute kidney injury (AKI). Ferroptosis, an iron-dependent form of cell death, is manifested by a toxic accumulation of lipid peroxides and ultrastructural changes in mitochondria. We herein investigated the effect of Visomitin (SKQ1), a novel mitochondria-targeting antioxidant, on several AKI models in vivo and in vitro. Our results revealed that SKQ1 treatment greatly reversed renal outcomes in cisplatin, ischemia-reperfusion injury (IRI), or folic acid-induced AKI models. These effects were reflected in attenuated levels of renal injury biomarkers, histologic indices of tubular injury, and inflammatory infiltration in the SKQ1-treated groups. Transcriptomics analysis depicted ferroptosis signaling as the most pronounced pathway downregulated after SKQ1 treatment. Consequently, administration of SKQ1 significantly ameliorated lipid peroxide accumulation and inhibited ferroptosis in the kidneys of mice with AKI. In cultured human proximal tubule epithelial cells (HK2), SKQ1 treatment markedly mitigated cisplatin-induced mitochondrial reactive oxygen species (ROS) production, resulting in lower levels of lipid peroxidation and ferroptosis. In conclusion, SKQ1 treatment protected against ischemic- or nephrotoxic-induced AKI by inhibiting ferroptosis in vivo and in vitro. These results could facilitate a broader understanding of the interaction between mitochondrial antioxidants and ferroptotic defense mechanisms, providing a possible therapeutic strategy in AKI.

Repurposing FDA-approved drugs against the toxicity of platinum-based anticancer drugs

Platinum-based anticancer drugs (PADs), mainly cisplatin, carboplatin, and oxaliplatin, are widely used efficacious long-standing anticancer agents for treating several cancer types. However, clinicians worry about PAD chemotherapy and its induction of severe non-targeted organ toxicity. Compelling evidence has shown that toxicity of PAD on delicate body organs is associated with free radical generation, DNA impairment, endocrine and mitochondrial dysfunctions, oxidative inflammation, apoptosis, endoplasmic reticulum stress, and activation of regulator signaling proteins, cell cycle arrest, apoptosis, and pathways. The emerging trend is the repurposing of FDA-approved non-anticancer drugs (FNDs) for combating the side effects toxicity of PADs. Thus, this review chronicled the mechanistic preventive and therapeutic effects of FNDs against PAD organ toxicity in preclinical studies. FNDs are potential clinical drugs for the modulation of toxicity complications associated with PAD chemotherapy. Therefore, FNDs may be suggested as non-natural agent inhibitors of unpalatable side effects of PADs.

Nephroprotective effect of exercise training in cisplatin-induced renal damage in mice: influence of training protocol

Cisplatin is an effective antineoplastic agent, but its use is limited by its nephrotoxicity caused by the oxidative stress in tubular epithelium of nephrons. On the other hand, regular exercise provides beneficial adaptations in different tissues and organs. As with many drugs, dosing is extremely important to get the beneficial effects of exercise. Thus, we aimed to investigate the influence of exercise intensity and frequency on cisplatin-induced (20 mg/kg) renal damage in mice. Forty male Swiss mice were divided into five experimental groups (n=8 per group): 1) sedentary; 2) low-intensity forced swimming, three times per week; 3) high-intensity forced swimming, three times per week; 4) low-intensity forced swimming, five times per week; and 5) high-intensity forced swimming, five times per week. Body composition, renal structure, functional indicators (plasma urea), lipid peroxidation, antioxidant enzyme activity, expression of genes related to antioxidant defense, and inflammatory and apoptotic pathways were evaluated. Comparisons considered exercise intensity and frequency. High lipid peroxidation was observed in the sedentary group compared with trained mice, regardless of exercise intensity and frequency. Groups that trained three times per week showed more benefits, as reduced tubular necrosis, plasma urea, expression of CASP3 and Rela (NFkB subunit-p65) genes, and increased total glutathione peroxidase activity. No significant difference in Nfe2l2 (Nrf2) gene expression was observed between groups. Eight weeks of regular exercise training promoted nephroprotection against cisplatin-mediated oxidative injury. Exercise frequency was critical for nephroprotection.

Tubular Mitochondrial Dysfunction, Oxidative Stress, and Progression of Chronic Kidney Disease

Acute kidney injury (AKI) and chronic kidney disease (CKD) are interconnected conditions, and CKD is projected to become the fifth leading global cause of death by 2040. New therapeutic approaches are needed. Mitochondrial dysfunction and oxidative stress have emerged as drivers of kidney injury in acute and chronic settings, promoting the AKI-to-CKD transition. In this work, we review the role of mitochondrial dysfunction and oxidative stress in AKI and CKD progression and discuss novel therapeutic approaches. Specifically, evidence for mitochondrial dysfunction in diverse models of AKI (nephrotoxicity, cytokine storm, and ischemia-reperfusion injury) and CKD (diabetic kidney disease, glomerulopathies) is discussed; the clinical implications of novel information on the key role of mitochondria-related transcriptional regulators peroxisome proliferator-activated receptor gamma coactivator 1-alpha, transcription factor EB (PGC-1α, TFEB), and carnitine palmitoyl-transferase 1A (CPT1A) in kidney disease are addressed; the current status of the clinical development of therapeutic approaches targeting mitochondria are updated; and barriers to the clinical development of mitochondria-targeted interventions are discussed, including the lack of clinical diagnostic tests that allow us to categorize the baseline renal mitochondrial dysfunction/mitochondrial oxidative stress and to monitor its response to therapeutic intervention. Finally, key milestones for further research are proposed.

Regulation of mitophagy through HIF-1α/miR-140-5p/PARKIN axis in acute kidney injury

Mitochondria homeostasis plays an important role in acute kidney injury (AKI). In this study, we aimed at identifying the mechanism of mitophagy regulation in AKI. Activation of mitophagy after ischemic kidney injury was visualized with increased expression of LC3, PINK1, PARKIN expression and with a subsequent decline in p62 levels. Immuohistochemistry staining showed higher LC3 levels in ischemic kidney injury mice. Further, differential expression of PARKIN targeting miRNAs revealed that miR-140-5p was significantly downregulated followed by ischemic kidney injury. miR-140-5p mimics suppressed PARKIN expressions and their mitochondrial translocation. Further, miR-140-5p mimics under hypoxia prevented mitophagosome formation. These effects on hypoxia-induced PARKIN expression and LC3/TOMM20 levels were reversed by antagomiR miR-140-5p treatment. Dual-luciferase reporter assay revealed that miR-140-5p had significant interaction with 3'UTR of PARKIN. Our findings show that HIF-1α is bound to miR-140-5p promoter and down regulates its expression and thereby promotes mitophagy process under hypoxic conditions. These results cumulatively show that HIF-1α regulates mitophagy during AKI through the regulation of miR-140-5p/PARKIN axis.

Mitochondrial activity is the key to the protective effect of β-Lapachone, a NAD+ booster, in healthy cells against cisplatin cytotoxicity

BACKGROUND

Cisplatin (CDDP) is a first-line chemotherapeutic drug for treating various cancers. However, CDDP also damages normal cells and causes many side effects. Recently, CDDP has been demonstrated to kill cancer cells by targeting mitochondria. Protecting mitochondria might be a potential therapeutic strategy for CDDP-induced side effects. β-Lapachone (β-lap), a recognized NAD⁺ booster, has been reported to regulate mitochondrial activity. However, it remains unclear whether maintaining mitochondrial activity is the key factor in the protective effects of β-lap in CDDP-treated normal cells.

PURPOSE

In this study, the protective effects of β-lap on mitochondria against CDDP cytotoxicity in normal cells were evaluated.

STUDY DESIGN

In vitro cell models were used in this study, including 3T3 fibroblasts, human dermal fibroblasts, MCF-7 breast cancer cells, and MDA-MB-231 breast cancer cells.

METHODS

Cells were treated with CDDP and β-lap, and cell survival, NAD⁺, mitochondrial activity, autophagy, and ATP production were measured. Various inhibitors and siRNAs were used to confirm the key signal underlying the protective effects of β-lap.

RESULTS

The results demonstrated that β-lap significantly decreased CDDP cytotoxicity in normal fibroblasts. With various inhibitors and siRNAs, β-lap reduced CDDP-induced damage to normal fibroblasts by maintaining mitochondrial activity and increasing autophagy through the NQO1/NAD⁺/SIRT1 axis. Most importantly, the protective effects of β-lap in fibroblasts did not affect the therapeutic effects of CDDP in cancer cells. This study indicated that mitochondrial activity, energy production, and NQO1 levels might be crucial responses separating normal cells from cancer cells under exposure to CDDP and β-lap.

CONCLUSION

β-lap could be a good synergistic drug for reducing the side effects of CDDP without affecting the anticancer drug effect.

Protective Effects of Liquiritigenin against Cisplatin-Induced Nephrotoxicity via NRF2/SIRT3-Mediated Improvement of Mitochondrial Function

Acute kidney injury (AKI) induced by cisplatin (CP), a first-line anticancer drug for chemotherapy, is common. To date, there is an urgent need to find effective treatments to reduce the nephrotoxicity caused by CP. Meanwhile, the restoration of mitochondrial dysfunction shows potential to be used as an adjunct to conventional therapeutic strategies. This study found that liquiritigenin can ameliorate mitochondrial dysfunction and acute kidney injury induced by CP in mice. The intraperitoneal injection of 15 mg/kg body weight liquiritigenin for 2 days markedly protected against CP-induced mitochondrial dysfunction, restored renal tubule and mitochondrial morphology, decreased blood Scr and BUN levels, and decreased cell apoptosis. Furthermore, the elevated expression of SIRT3 induced by liquiritigenin, which can be upregulated by NRF2, was confirmed in vivo and in vitro. The underlying protective mechanisms of liquiritigenin in CP-induced nephrotoxicity were then investigated. Molecular docking results showed that liquiritigenin has potent binding activities to KEAP1, GSK-3β and HRD1. Further results showed that liquiritigenin induced the nuclear translocation of NRF2 and increased the levels of mitochondrial bioenergetics-related protein such as PGC-1α, and TFAM, which are related to NRF2 activity and mitochondrial biogenesis. In addition, liquiritigenin was found to possibly reverse the decrease in BCL2/BAX ratio induced by CP in live cultured renal tubule epithelial cells. Collectively, these results indicated that liquiritigenin could be used as a potential nephroprotective agent to protect against cisplatin-induced acute kidney injury in a NRF2-dependent manner by improving mitochondria function.

Serum Proteomics in Patients with Head and Neck Cancer: Peripheral Blood Immune Response to Treatment

In this real-world study, the aims were to prospectively evaluate the expression of inflammatory proteins in serum collected from head and neck cancer patients before and after treatment, and to assess whether there were differences in expression associated with treatment modalities. The mixed study cohort consisted of 180 patients with head and neck cancer. The most common tumor sites were the oropharynx (n = 81), the oral cavity (n = 53), and the larynx (n = 22). Blood tests for proteomics analysis were carried out before treatment, 7 weeks after the start of treatment, and 3 and 12 months after the termination of treatment. Sera were analyzed for 83 proteins using an immuno-oncology biomarker panel (Olink, Uppsala, Sweden). Patients were divided into four treatment groups: surgery alone (Surg group, n = 24), radiotherapy with or without surgery (RT group, n = 94), radiotherapy with concomitant cisplatin (CRT group, n = 47), and radiotherapy with concomitant targeted therapy (RT Cetux group, n = 15). For the overall cohort, the expression levels of 15 of the 83 proteins changed significantly between the pretreatment sample and the sample taken 7 weeks after the start of treatment. At 7 weeks after the start of treatment, 13 proteins showed lower expression in the CRT group compared to the RT group. The majority of the inflammatory proteins had returned to their pretreatment levels after 12 months. It was clearly demonstrated that cisplatin-based chemoradiation has immunological effects in patients with head and neck cancer. This analysis draws attention to several inflammatory proteins that are of interest for further studies.

Irbesartan decreased mitochondrial stress related apoptosis in cisplatin induced acute kidney injury via regulating BCL-2/BAX signaling

BACKGROUND

Cisplatin (CPN) is used in the treatment of various cancers. However, the especially nephrotoxic effect is limiting its use. We aimed to evaluate the renoprotective effects of Irbesartan (IBN) on CPN-induced acute kidney injury via mitochondrial stress related apoptosis.

METHODS AND RESULTS

32 rats were divided into 4 groups as control, CPN, CPN + IBN and IBN. Water or IBN 50 mg/kg (orally) was administered for 7 days and a single dose of CPN (5 mg/kg) intraperitoneally was given CPN and CPN + IBN groups on fourth day of experiment. At the end of the experiment, serum BUN and creatinine (Cre) levels, which are the indicators of kidney function are measured. Bcl-2-associated X protein (Bax) and B-cell-lymphoma-2 (Bcl-2) mRNA levels were analyzed by using qRT-PCR from kidneys as a mitochondrial stress indicator. Also, active caspase-3(cas-3) protein and tumor necrosis factor alpha (TNF-α) expressions were examined by immunostaining of the kidney tissues. For evaluation of oxidative stress, malondialdehyde (MDA), total oxidant status (TOS) and total antioxidant status (TAS) levels of renal tissues were measured and oxidative stress index (OSI) were calculated. CPN increased serum BUN and creatinine levels. Also, MDA, TOS and OSI levels were significantly elevated and TAS levels decreased in the CPN group. Moreover, CPN elevated the levels of Bax, active cas-3 protein and TNF-α expressions and suppressed Bcl-2 levels. IBN treatment reversed all these changes.

CONCLUSIONS

IBN significantly regressed kidney damage by its anti-inflammatory and antioxidant activity via inhibiting mitochondrial stress. IBN could be used as a renoprotective agent in CPN-induced kidney injury.

Unexpected Enhancement of Cytotoxicity of Cisplatin in a Rat Kidney Proximal Tubular Cell Line Overexpressing Mitochondrial Glutathione Transport Activity

In previous studies, we identified the two principal transporters that mediate the uptake of glutathione (GSH) from cytoplasm into the mitochondrial matrix of rat kidney proximal tubular cells. We hypothesized that genetic modulation of transporter expression could markedly alter susceptibility of renal proximal tubular cells to a broad array of oxidants and mitochondrial toxicants. Indeed, we previously showed that overexpression of either of these transporters resulted in diminished susceptibility to several chemicals. In the present work, we investigated the influence of overexpression of the mitochondrial 2-oxoglutarate carrier (OGC) in NRK-52E cells on the cytotoxicity of the antineoplastic drug cisplatin. In contrast to previous results showing that overexpression of the mitochondrial OGC provided substantial protection of NRK-52E cells from injury due to several toxicants, we found a remarkable enhancement of cellular injury from exposure to cisplatin as compared to wild-type NRK-52E cells. Despite the oxidative stress that cisplatin is known to cause in the renal proximal tubule, the increased concentrations of mitochondrial GSH associated with OGC overexpression likely resulted in increased delivery of cisplatin to molecular targets and increased cellular injury rather than the typical protection observed in the previous work.

Antioxidant Roles of SGLT2 Inhibitors in the Kidney

The reduction-oxidation (redox) system consists of the coupling and coordination of various electron gradients that are generated thanks to serial reduction-oxidation enzymatic reactions. These reactions happen in every cell and produce radical oxidants that can be mainly classified into reactive oxygen species (ROS) and reactive nitrogen species (RNS). ROS and RNS modulate cell-signaling pathways and cellular processes fundamental to normal cell function. However, overproduction of oxidative species can lead to oxidative stress (OS) that is pathological. Oxidative stress is a main contributor to diabetic kidney disease (DKD) onset. In the kidney, the proximal tubular cells require a high energy supply to reabsorb proteins, metabolites, ions, and water. In a diabetic milieu, glucose-induced toxicity promotes oxidative stress and mitochondrial dysfunction, impairing tubular function. Increased glucose level in urine and ROS enhance the activity of sodium/glucose co-transporter type 2 (SGLT2), which in turn exacerbates OS. SGLT2 inhibitors have demonstrated clear cardiovascular benefits in DKD which may be in part ascribed to the generation of a beneficial equilibrium between oxidant and antioxidant mechanisms.

Protective effects of low-temperature plasma on cisplatin-induced nephrotoxicity

The application of atmospheric pressure low-temperature plasma (LTP) in medical treatment has received extensive attention owing to its redox regulatory and anti-inflammatory properties. Nephrotoxicity due to oxidative stress and inflammation is the main adverse effect of cisplatin. In the present study, rats with cisplatin-induced nephrotoxicity were treated with LTP to investigate its potential protective effect. The results showed that LTP treatment has multiple protective effects on cisplatin-induced nephrotoxicity. It significantly improved clinical indicators such as survival rate, water intake, food intake, body weight, and mobility, as well as physiological indexes such as reduced renal index and levels of serum urea, creatinine, and total bilirubin; pathological indicators such as reduced tubular injury, inflammatory infiltration, tubulointerstitial fibrosis, and apoptosis; cell survival indicators such as decreased protein levels of Caspase-3 and Bax and increased Bcl-2; anti-oxidation status such as reduced malondialdehyde content and increased activities of catalase, superoxide dismutase, and glutathione peroxidase; and reduced inflammatory factors such as TNF-α in kidney tissues. Specially, LTP treatment did not influence the anticancer effect of cisplatin as observed in the solid tumor mouse model established by subcutaneously inoculating H22 cells. Moreover, LTP did not influence the physiological and pathological indicators of normal rats, suggesting its biological safety. In conclusion, LTP can protect against cisplatin-induced nephrotoxicity through its anti-oxidation, anti-inflammation, and anti-apoptosis effects, without influencing the anticancer effect of cisplatin.

Activation of activator protein-1-fibroblast growth factor 21 signaling attenuates Cisplatin hepatotoxicity

Fibroblast growth factor (Fgf/FGF) 21, which plays important roles in sugar, lipid and energy metabolism, has been accepted as a mito-stress marker gene. We recently reported that FGF21 expression can be up-regulated via activation of aryl hydrocarbon receptor (AhR) or glucocorticoid receptor (GR) and that FGF21 plays important cytoprotective roles. Cisplatin (cis-diamminedichloroplatinum, CDDP) is a widely used chemotherapeutic drug. Numerous adverse effects including hepatotoxicity have been noted during CDDP therapy. It is known that CDDP can induce mitochondrial dysfunction. The studies were designed to determine the regulation of Fgf/FGF21 expression by CDDP, and to characterize the underlying mechanisms of its regulation, as well as to determine the impact of gain or loss of Fgf/FGF21 function on the progression of CDDP hepatotoxicity. Our results showed that CDDP and phorbol ester induced mRNA and protein expression of Fgf/FGF21 and β-Klotho, two essential components of Fgf21 signaling, in mouse livers and cultured mouse/human hepatocytes. Luciferase reporter assays and ChIP-qPCR assays demonstrated that the cJun-AP-1 activation is responsible for CDDP- and phorbol ester-induced Fgf/FGF21 expression. Such induction is abolished after cotreated with AP-1 inhibitor SR11302. In addition, CDDP produces more severe liver injury in Fgf21-null than wild-type mice. Pre-treatment of GR activator dexamethasone or AhR activator β-Naphthoflavone, both of which can induce Fgf21 expression, attenuated CDDP-induced hepatotoxicity in vivo and in vitro. In conclusion, Fgf/FGF21-β-Klotho signaling can be activated via AP-1 activation. Gain of Fgf/FGF21 function attenuates the progression of CDDP hepatotoxicity, which may be considered clinically to improve CDDP therapy.

Protective Effects of Low-Dose Alcohol against Acute Stress-Induced Renal Injury in Rats: Involvement of CYP4A/20-HETE and LTB4/BLT1 Pathways

Low-dose alcohol possesses multiple bioactivities. Accordingly, we investigated the protective effect and related molecular mechanism of low-dose alcohol against acute stress- (AS-) induced renal injury. Herein, exhaustive swimming for 15 min combined with restraint stress for 3 h was performed to establish a rat acute stress model, which was verified by an open field test. Evaluation of renal function (blood creatinine and urea nitrogen), urine test (urine leukocyte esterase and urine occult blood), renal histopathology, oxidative stress, inflammation, and apoptosis was performed. The key indicators of the cytochrome P450 (CYP) 4A1/20-hydroxystilbenetetraenoic acid (20-HETE) pathway, cyclooxygenase (COX)/prostaglandin E₂ (PGE₂) pathway, and leukotriene B₄ (LTB₄)/leukotriene B₄ receptor 1 (BLT1) pathway were measured by real-time PCR and ELISA. We found that low-dose alcohol (0.05 g/kg, i.p.) ameliorated AS-induced renal dysfunction and histological damage. Low-dose alcohol also attenuated AS-induced oxidative stress and inflammation, presenting as reduced malondialdehyde and hydrogen peroxide formation, increased superoxide dismutase and glutathione activity, and decreased myeloperoxidase, interleukin-6, interleukin-1β, and monocyte chemoattractant protein-1 levels (P < 0.05). Moreover, low-dose alcohol alleviated AS-induced apoptosis by downregulating Bax and cleaved caspase 3 protein expression and reduced numbers of terminal deoxynucleotidyl transferase-mediated dUTP nick-end label-positive cells (P < 0.01). Correlation analysis indicated that 20-HETE was strongly correlated with oxidative stress, while LTB₄ was strongly correlated with inflammation. Low-dose alcohol inhibited AS-induced increases in CYP4A1, CYP4A2, CYP4A3, CYP4A8, and BLT1 mRNA levels and LTB₄ and 20-HETE content (P < 0.01). Interestingly, low-dose alcohol had no effect on COX1 or COX2 mRNA expression or the concentration of PGE₂. Furthermore, low-dose alcohol reduced calcium-independent phospholipase A₂ mRNA expression, but did not affect secreted phospholipase A₂ or cytosolic phospholipase A₂ mRNA expression. Together, these results indicate that low-dose alcohol ameliorated AS-induced renal injury by inhibiting CYP4A/20-HETE and LTB₄/BLT1 pathways, but not the COX/PGE₂ pathway.

Cyclophilin D Promotes Acute, but Not Chronic, Kidney Injury in a Mouse Model of Aristolochic Acid Toxicity

The plant-derived toxin, aristolochic acid (AA), is the cause of Chinese Herb Nephropathy and Balkan Nephropathy. Ingestion of high dose AA induces acute kidney injury, while chronic low dose ingestion leads to progressive kidney disease. Ingested AA is taken up by tubular epithelial cells of the kidney, leading to DNA damage and cell death. Cyclophilin D (CypD) participates in mitochondrial-dependent cell death, but whether this mechanism operates in acute or chronic AA-induced kidney injury is unknown. We addressed this question by exposing CypD-/- and wild type (WT) mice to acute high dose, or chronic low dose, AA. Administration of 5 mg/kg AA to WT mice induced acute kidney injury 3 days later, characterised by loss of kidney function, tubular cell damage and death, and neutrophil infiltration. All of these parameters were significantly reduced in CypD-/- mice. Chronic low dose (2 mg/kg AA) administration in WT mice resulted in chronic kidney disease with impaired renal function and renal fibrosis by day 28. However, CypD-/- mice were not protected from AA-induced chronic kidney disease. In conclusion, CypD facilitates AA-induced acute kidney damage, but CypD does not contribute to the transition of acute kidney injury to chronic kidney disease during ongoing AA exposure.

Protective Effect of Pyxinol, One Active Ingredient of Lichenes on Cisplatin-Induced Nephrotoxicity via Ameliorating DNA Damage Response

Background: Cisplatin is a valuable chemotherapeutic agent against malignant tumors. However, the clinical use of cisplatin is limited by its side effects such as renal injury. Pyxinol is an active constituent of Lichenes and its effects on cisplatin-induced nephrotoxicity is currently unknown. This study aims to examine the potential protective effects of pyxinol on cisplatin-induced renal injury and explore the underlying mechanisms.

Methods:In vivo rat model of cisplatin-induced nephrotoxicity was induced by intraperitoneal (i.p) administration of cisplatin. The blood urea nitrogen and creatinine levels were measured and renal histological analysis was conducted to evaluate the renal function; The TUNEL staining, western blotting and real-time PCR assays were conducted to examine related molecular changes. Finally, the in vivo anti-tumor efficacy was examined in the xenograft tumor model using nude mice.

Results: Pretreatment with pyxinol attenuated cisplatin-induced increase in blood urea nitrogen, creatinine and urinary protein excretion and the magnitude of injury in the renal tubules. Pyxinol ameliorated the activation of p53 via attenuating the DNA damage response, which then attenuated the tubular cell apoptosis. Finally, pyxinol could potentiate the in vivo anti-tumor efficacy of cisplatin against the xenograft tumor of cervical cancer cells in nude mice.

Conclusions: Combining pyxinol with cisplatin could alleviate cisplatin-induced renal injury without decreasing its therapeutic efficacy, which might represent a beneficial adjunct therapy for cisplatin-based chemotherapeutic regimens in the clinic.

Mechanism Prediction of Astragalus membranaceus against Cisplatin-Induced Kidney Damage by Network Pharmacology and Molecular Docking

Background

Cisplatin is a frequently used and effective chemotherapy drug in clinical practice, but severe side effects limit its use, among which nephrotoxicity is considered the most serious and prolonged damage to the body. Astragalus membranaceus (AM) is a well-known herbal medicine, and modern pharmacological studies have confirmed its antioxidant, immunomodulatory, and antiapoptotic effects. Clinical studies have shown that AM and its active components can attenuate cisplatin-induced kidney damage, but the molecular mechanism has not been fully expounded.

Materials and Methods

First, the components and targets information of AM were collected from the TCMSP, and the relevant targets of cisplatin-induced kidney damage were accessed from the GeneCards and OMIM databases. Then, the core targets were selected by the Venn diagram and network topology analysis, which was followed by GO and KEGG pathway enrichment analysis. Finally, we construct a component-target-pathway network. Furthermore, molecular docking was carried out to identify the binding activity between active components and key targets.

Results

A total of 20 active components and 200 targets of AM and 646 targets related to cisplatin-induced kidney damage were obtained. 91 intersection targets were found between AM and cisplatin-induced kidney damage. Then, 16 core targets were identified, such as MAPK1, TNF-α, and p53. Furthermore, GO and KEGG pathway enrichment analysis suggested that MAPK, Toll-like receptor, and PI3K-Akt signaling pathways may be of significance in the treatment of cisplatin-induced kidney damage by AM. Molecular docking indicated that quercetin and kaempferol had high binding affinities with many core targets.

Conclusion

In summary, the active components, key targets, and signaling pathways of AM in the treatment of cisplatin-induced kidney damage were predicted in this study, which contributed to the development and application of AM.

Bioactive peptide apelin rescues acute kidney injury by protecting the function of renal tubular mitochondria

Mitochondrial dysfunction in proximal tubular epithelial cells is a key event in acute kidney injury (AKI), which is a risk factor for the development of chronic kidney disease (CKD). Apelin is a bioactive peptide that protects against AKI by alleviating inflammation, inhibiting apoptosis, and preventing lipid oxidation, but its role in protecting against mitochondrial damage remains unknown. Herein, we examined the protective effects of apelin on mitochondria in cisplatin-stimulated human renal proximal tubular epithelial cells and evaluated its therapeutic efficacy in cisplatin-induced AKI mice. In vitro, apelin inhibited the cisplatin-induced mitochondrial fission factor (MFF) upregulation and the fusion-promoting protein optic atrophy 1 (OPA1) downregulation. Apelin co-treatment reversed the decreased levels of the deacetylase, Sirt3, and the increased levels of protein acetylation in mitochondria of cisplatin-stimulated cells. Overall, apelin improved the mitochondrial morphology and membrane potential in vitro. In the AKI model, apelin administration significantly attenuated mitochondrial damage, as evidenced by longer mitochondrial profiles and increased ATP levels in the renal cortex. Suppression of MFF expression, and maintenance of Sirt3 and OPA1 expression in apelin-treated AKI mice was also observed. Finally, exogenous administration of apelin normalized the serum level of creatinine and urea nitrogen and the urine levels of NGAL and Kim-1. We also confirmed a regulatory pathway that drives mitochondrial homeostasis including PGC-1α, ERRα and Sirt3. In conclusion, we demonstrated that apelin ameliorates renal functions by protecting tubular mitochondria through Sirt3 upregulation, which is a novel protective mechanism of apelin in AKI. These results suggest that apelin has potential renoprotective effects and may be an effective agent for AKI treatment to significantly retard CKD progression.

Necrostatins regulate apoptosis, necroptosis, and inflammation in cisplatin-induced nephrotoxicity in LLC-PK1 cells

Acute kidney injury (AKI) is a common clinical problem that is associated with high mortality due to multiple complex mechanisms. Cisplatin is the most important and highly effective chemotherapeutic agent used for the treatment of various solid tumors; however, it is associated with dose-dependent adverse effects, particularly in the kidney where it can cause severe nephrotoxicity. The pathophysiological basis of cisplatin-induced nephrotoxicity has been investigated over the last few decades, and the key pathological occurrences in cisplatin nephrotoxicity include renal tubular cell injury and death. Necrostatin-1 (Nec-1) has been confirmed to act as a specific and potent small-molecule inhibitor of necroptosis. However, the effects of three structurally distinct necrostatins on cisplatin-induced nephrotoxicity remain ambiguous. The aim of this study was to determine if three types of necrostatins (Nec-1, Nec-3-A, and/or Nec-3-B) can exert protective effects in regard to the AKI induced by cisplatin. Our results indicated that necrostatins can prevent cisplatin induced nephrotoxicity via modulating apoptotic pathways through the suppression of cleaved caspase-3 and also by influencing the function of mitogen-activated protein kinase pathway members, including extracellular signal-regulated kinases, c-Jun N-terminal kinases, and p38, in the renal tubular epithelial cell line LLC-PK1. These findings suggest that necrostatins exert beneficial anti-apoptotic effects in the context of AKI induced by cisplatin.

Annexin A1 Tripeptide Mimetic Increases Sirtuin-3 and Augments Mitochondrial Function to Limit Ischemic Kidney Injury

Background: Acute kidney injury (AKI) is one of the most common organ failures following surgery. We have developed a tripeptide mimetic (ANXA1sp) of the parent annexin A1 molecule that shows promise as an organ protectant limiting cellular stress; however, its potential as a kidney protective agent remains unexplored, and its mechanism of action is poorly understood. Our hypothesis was that ANXA1sp would limit kidney injury following surgical ischemic kidney injury. Methods: In a blinded fashion, wildtype mice were assigned to receive vehicle control or ANXA1sp one hour prior to and one hour after kidney vascular clamping. Our primary outcomes were markers of kidney injury and function as measured by serum creatinine and histologic injury scoring of kidney tissue sections. Immunofluorescence microscopy, real-time PCR, and Western blot were used to assess cell death, oxidative stress, and mitochondrial biomarkers. An in vitro model of oxygen-glucose deprivation in immortalized kidney tubule cells was used. Results: ANXA1sp given prior to and after ischemic kidney injury abrogated ischemic kidney injury. ANXA1sp limited cell death both in vivo and in vitro and abrogated oxidative stress following ischemia. ANXA1sp significantly increased the expression of markers associated with protective mitophagy and limited the expression of markers associated with detrimental mitochondrial fission. ANXA1sp upregulated the expression of the mitochondrial protectant sirtuin-3 (SIRT3) in the mitochondria of kidney tubular cells. Silencing of SIRT3 reversed ANXA1sp-mediated protection against hypoxic cell death. Conclusions: ANXA1sp limits kidney injury, upregulates SIRT3, and preserves mitochondrial integrity following ischemic kidney injury. ANXA1sp holds considerable promise as a perioperative kidney protectant prior to ischemia inducing surgery and kidney transplantation.

Human antigen R regulates hypoxia-induced mitophagy in renal tubular cells through PARKIN/BNIP3L expressions

Mitochondrial dysfunction contributes to the pathophysiology of acute kidney injury (AKI). Mitophagy selectively degrades damaged mitochondria and thereby regulates cellular homeostasis. RNA-binding proteins (RBPs) regulate RNA processing at multiple levels and thereby control cellular function. In this study, we aimed to understand the role of human antigen R (HuR) in hypoxia-induced mitophagy process in the renal tubular cells. Mitophagy marker expressions (PARKIN, p-PARKIN, PINK1, BNIP3L, BNIP3, LC3) were determined by western blot analysis. Immunofluorescence studies were performed to analyze mitophagosome, mitolysosome, co-localization of p-PARKIN/TOMM20 and BNIP3L/TOMM20. HuR-mediated regulation of PARKIN/BNIP3L expressions was determined by RNA-immunoprecipitation analysis and RNA stability experiments. Hypoxia induced mitochondrial dysfunction by increased ROS, decline in membrane potential and activated mitophagy through up-regulated PARKIN, PINK1, BNIP3 and BNIP3L expressions. HuR knockdown studies revealed that HuR regulates hypoxia-induced mitophagosome and mitolysosome formation. HuR was significantly bound to PARKIN and BNIP3L mRNA under hypoxia and thereby up-regulated their expressions through mRNA stability. Altogether, our data highlight the importance of HuR in mitophagy regulation through up-regulating PARKIN/BNIP3L expressions in renal tubular cells.

Suppressed Hepatic Production of Indoxyl Sulfate Attenuates Cisplatin-Induced Acute Kidney Injury in Sulfotransferase 1a1-Deficient Mice

Endogenous factors involved in the progression of cisplatin nephropathy remain undetermined. Here, we demonstrate the toxico-pathological roles of indoxyl sulfate (IS), a sulfate-conjugated uremic toxin, and sulfotransferase 1A1 (SULT1A1), an enzyme involved in its synthesis, in cisplatin-induced acute kidney injury using Sult1a1-deficient (Sult1a1^-/- KO) mice. With cisplatin administration, severe kidney dysfunction, tissue damage, and apoptosis were attenuated in Sult1a1^-/- (KO) mice. Aryl hydrocarbon receptor (AhR) expression was increased by treatment with cisplatin in mouse kidney tissue. Moreover, the downregulation of antioxidant stress enzymes in wild-type (WT) mice was not observed in Sult1a1^-/- (KO) mice. To investigate the effect of IS on the reactive oxygen species (ROS) levels, HK-2 cells were treated with cisplatin and IS. The ROS levels were significantly increased compared to cisplatin or IS treatment alone. IS-induced increases in ROS were reversed by downregulation of AhR, xanthine oxidase (XO), and NADPH oxidase 4 (NOX4). These findings suggest that SULT1A1 plays toxico-pathological roles in the progression of cisplatin-induced acute kidney injury, while the IS/AhR/ROS axis brings about oxidative stress.

Florfenicol causes excessive lipid peroxidation and apoptosis induced renal injury in broilers

In order to study the effects and mechanism of florfenicol (FFC) on the kidney function of broilers, 180 1-day-old broilers were randomly divided into 6 groups, 30 in each group. Except for the control group, different doses of FFC were added to drinking water in the other 5 groups (0.15 g/L, 0.3 g/L, 0.6 g/L, 1.2 g/L and 1.8 g/L). After continuous administration for 5 days, renal histopathological changes, serum renal function indicators, renal peroxidation products and antioxidant factors, and apoptotic factors were detected in broilers aged 21 and 42 days. The results showed that compared with the control group, the kidney tissue structure was disordered, the glomerulus was atrophic, the cystic cavity was enlarged, and the epithelial cells of renal tubules were seriously vacuolated in broilers of treatment groups. And with the growth of broilers, the kidney injury of broilers in the low-dose FFC group was relieved. FFC significantly increased the contents of uric acid (UA), blood urea nitrogen (BUN), creatinine (CRE) in serum and malondialdehyde (MDA) in kidney of broilers, but significantly reduced the levels of glutathione (GSH), superoxide dismutase (SOD) and catalase (CAT) in kidney. FFC significantly inhibited the mRNA relative transcriptional levels of nuclear factor-erythroid 2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1) and nicotinamide adenine dinucleotide phosphate: quinone oxidoreductase-1 (NQO-1), and increased the mRNA and protein expression levels of p53, Caspase-3 and Caspase-6 in kidney tissue of broilers. It is concluded that FFC has certain nephrotoxicity to broilers, and its effect on kidney is dose-dependent and reversible. FFC causes intense lipid peroxidation in broiler kidney by inhibiting the expression of related factors in the downstream signal pathway of Nrf2. FFC can also up-regulate the expression of pro-apoptotic factors and accelerate the abnormal apoptosis of renal cells, thus seriously affecting the renal function of broilers.

Amlodipine alleviates cisplatin-induced nephrotoxicity in rats through gamma-glutamyl transpeptidase (GGT) enzyme inhibition, associated with regulation of Nrf2/HO-1, MAPK/NF-κB, and Bax/Bcl-2 signaling

BACKGROUND

The therapeutic utility of the effective chemotherapeutic agent cisplatin is hampered by its nephrotoxic effect. We aimed from the current study to examine the possible protective effects of amlodipine through gamma-glutamyl transpeptidase (GGT) enzyme inhibition against cisplatin nephrotoxicity.

METHODS

Amlodipine (5 mg/kg, po) was administered to rats for 14 successive days. On the 10th day, nephrotoxicity was induced by a single dose of cisplatin (6.5 mg/kg, ip). On the last day, blood samples were collected for estimation of kidney function, while kidney samples were used for determination of GGT activity, oxidative stress, inflammatory, and apoptotic markers, along with histopathological evaluation.

RESULTS

Amlodipine alleviated renal injury that was manifested by significantly diminished serum creatinine and blood urea nitrogen levels, compared to cisplatin group. Amlodipine inhibited GGT enzyme, which participates in the metabolism of extracellular glutathione (GSH) and platinum-GSH-conjugates to a reactive toxic thiol. Besides, amlodipine diminished mRNA expression of NADPH oxidase in the kidney, while enhanced the anti-oxidant defense by activating Nrf2/HO-1 signaling. Additionally, it showed marked anti-inflammatory response by reducing expressions of p38 mitogen-activated protein kinase (p38 MAPK) and nuclear factor-kappa B (NF-κB), with subsequent down-regulation of tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), and vascular cell adhesion molecule-1 (VCAM-1). Moreover, amlodipine reduced Bax/Bcl-2 ratio and elevated hepatocyte growth factor (HGF), thus favoring renal cell survival.

CONCLUSIONS

Effective GGT inhibition by amlodipine associated with enhancement of anti-oxidant defense and suppression of inflammatory signaling and apoptosis support our suggestion that amlodipine could replace toxic GGT inhibitors in protection against cisplatin nephrotoxicity.

NHERF1 Loss Upregulates Enzymes of the Pentose Phosphate Pathway in Kidney Cortex

(1) Background: We previously showed Na/H exchange regulatory factor 1 (NHERF1) loss resulted in increased susceptibility to cisplatin nephrotoxicity. NHERF1-deficient cultured proximal tubule cells and proximal tubules from NHERF1 knockout (KO) mice exhibit altered mitochondrial protein expression and poor survival. We hypothesized that NHERF1 loss results in changes in metabolic pathways and/or mitochondrial dysfunction, leading to increased sensitivity to cisplatin nephrotoxicity. (2) Methods: Two to 4-month-old male wildtype (WT) and KO mice were treated with vehicle or cisplatin (20 mg/kg dose IP). After 72 h, kidney cortex homogenates were utilized for metabolic enzyme activities. Non-treated kidneys were used to isolate mitochondria for mitochondrial respiration via the Seahorse XF24 analyzer. Non-treated kidneys were also used for LC-MS analysis to evaluate kidney ATP abundance, and electron microscopy (EM) was utilized to evaluate mitochondrial morphology and number. (3) Results: KO mouse kidneys exhibit significant increases in malic enzyme and glucose-6 phosphate dehydrogenase activity under baseline conditions but in no other gluconeogenic or glycolytic enzymes. NHERF1 loss does not decrease kidney ATP content. Mitochondrial morphology, number, and area appeared normal. Isolated mitochondria function was similar between WT and KO. Conclusions: KO kidneys experience a shift in metabolism to the pentose phosphate pathway, which may sensitize them to the oxidative stress imposed by cisplatin.

The implication of mitochondrial dysfunction and mitochondrial oxidative damage in di (2-ethylhexyl) phthalate induced nephrotoxicity in both in vivo and in vitro models

Di-(2-ethylhexyl) phthalate (DEHP) and its main metabolite, monoethylhexyl phthalic acid (MEHP), are a serious threat to human and animals' health in the current century. However, their exact mechanism to induce nephrotoxicity is not clear. In the current study, we addressed toxic effects of MEHP and DEHP on embryonic human kidney cells (HEK-293 cell line) and kidney tissue of rats, respectively. In the HEK-293, MTT assay and oxidative stress parameters were measured after treatment with different concentrations of MEHP. For in vivo study, rats were treated with different doses of DEHP (50, 100, 200, 400 mg/kg) via gavage administration for 45 days. The renal function biomarkers (BUN and creatinine) were determined in serum of rats. Mitochondrial toxic parameters including MTT, mitochondrial membrane potential (MMP), mitochondrial swelling, and also oxidative stress parameters were measured in isolated kidney mitochondria. Histopathological effects of DEHP were also evaluated in rats' kidneys. We demonstrated that MEHP induced oxidative stress and cytotoxicity in HEK-293 cells in a concentration dependent manner. The administration of DEHP led to histopathological changes in kidney tissue, which concurred with BUN and creatinine alternations in serum of rats. The results of present study showed a significant mitochondrial dysfunction and oxidative stress confirmed by enhancement of mitochondrial swelling, mitochondrial reactive oxygen species (ROS) and malondialdehyde (MDA), and reduction of MMP and mitochondrial glutathione (GSH). Taken together, this study showed that DEHP/MEHP resulted in mitochondrial dysfunction and oxidative damage, which suggest a vital role of mitochondria in DEHP/MEHP-induced nephrotoxicity.

Isocitrate dehydrogenase 2 deficiency aggravates prolonged high-fat diet intake-induced hypertension

The development of hypertension is associated with mitochondrial redox balance disruptions. NADP⁺-dependent isocitrate dehydrogenase 2 (IDH2) plays an important role in the maintenance of mitochondrial redox balance by producing mitochondrial NADPH, which is an essential cofactor in the reduction of glutathione (from GSSG to GSH) to reduced form of glutathione (GSH). We investigated the association of IDH2 between the development of prolonged high-fat diet (HFD)-induced hypertension. Idh2 gene-deleted (Idh2^-/-) male mice and wild-type (Idh2^+/+) littermates were fed either HFD or low-fat diet (LFD). Some mice were administrated with Mito-TEMPO, a mitochondria-specific antioxidant. HFD feeding increased blood pressure (BP) in both Idh2^-/- mice and Idh2^+/+ mice. HFD-induced BP increase was greater in Idh2^-/- than Idh2^+/+ mice. HFD intake decreased IDH2 activity, NADPH levels, and the GSH/(GSH + GSSG) ratio in the renal mitochondria. However, HFD intake increased mitochondrial ROS levels, along with the accompanying oxidative stress and damage. HFD intake increased angiotensin II receptor 1 type 1 mRNA levels in the kidneys and plasma renin and angiotensin II concentrations. These HFD-induced changes were more prominent in Idh2^-/- mice than Idh2^+/+ mice. Mito-TEMPO mitigated the HFD-induced changes in both Idh2^-/- and Idh2^+/+ mice, with greater effects in Idh2^-/- mice than Idh2^+/+ mice. These results indicate that prolonged HFD intake disrupts the IDH2-NADPH-GSH-associated antioxidant system and activates the renin-angiotensin system in the kidney, leading to increased BP, suggesting that IDH2 is a critical enzyme in the development of hypertension and that the IDH2-associated antioxidant system could serve as a potential hypertension treatment target.

Sirt3 modulates fatty acid oxidation and attenuates cisplatin-induced AKI in mice

Fatty acid oxidation (FAO) dysfunction is one of the important mechanisms of renal fibrosis. Sirtuin 3 (Sirt3) has been confirmed to alleviate acute kidney injury (AKI) by improving mitochondrial function and participate in the regulation of FAO in other disease models. However, it is not clear whether Sirt3 is involved in regulating FAO to improve the prognosis of AKI induced by cisplatin. Here, using a murine model of cisplatin-induced AKI, we revealed that there were significantly FAO dysfunction and extensive lipid deposition in the mice with AKI. Metabolomics analysis suggested reprogrammed energy metabolism and decreased ATP production. In addition, fatty acid deposition can increase reactive oxygen species (ROS) production and induce apoptosis. Our data suggested that Sirt3 deletion aggravated FAO dysfunction, resulting in increased apoptosis of kidney tissues and aggravated renal injury. The activation of Sirt3 by honokiol could improve FAO and renal function and reduced fatty acid deposition in wide-type mice, but not Sirt3-defective mice. We concluded that Sirt3 may regulate FAO by deacetylating liver kinase B1 and activating AMP-activated protein kinase. Also, the activation of Sirt3 by honokiol increased ATP production as well as reduced ROS and lipid peroxidation through improving mitochondrial function. Collectively, these results provide new evidence that Sirt3 is protective against AKI. Enhancing Sirt3 to improve FAO may be a potential strategy to prevent kidney injury in the future.