Ursodeoxycholic acid protects against cisplatin-induced acute kidney injury and mitochondrial dysfunction through acting on ALDH1L2

Integrin-Linked Kinase (ILK) Promotes Mitochondrial Dysfunction by Decreasing CPT1A Expression in a Folic Acid-Based Model of Kidney Disease

Integrin-linked kinase (ILK) is a key scaffolding protein between extracellular matrix protein and the cytoskeleton and has been implicated previously in the pathogenesis of renal damage. However, its involvement in renal mitochondrial dysfunction remains to be elucidated. We studied the role of ILK and its downstream regulations in renal damage and mitochondria function both in vivo and vitro, using a folic acid (FA)-induced kidney disease model. Wild type (WT) and ILK conditional-knockdown (cKD-ILK) mice were injected with a single intraperitoneal dose of FA and studied after 15 days of chronic renal damage progression. Human Kidney tubular epithelial cells (HK2) were transfected with specific siRNAs targeting ILK, glycogen synthase kinase 3-β (GSK3β), or CCAAT/enhancer binding protein-β (C/EBPβ). The expressions and activities of renal ILK, GSK3β, C/EBPβ, mitochondrial oxidative phosphorylation enzymes, and mitochondrial membrane potential were assessed. Additionally, the expression of markers for fibrosis fibronectin (FN) and collagen 1 (COL1A1), for autophagy p62 and cytosolic light chain 3 (LC3B) isoforms II and I, and mitochondrial homeostasis marker carnitine palmitoyl-transferase 1A (CPT1A) were evaluated using immunoblotting, RT-qPCR, immunofluorescence, or colorimetric assays. FA upregulated ILK expression, leading to the decrease of GSK3β activity, increased tubular fibrosis, and produced mitochondrial dysfunction, both in vivo and vitro. These alterations were fully or partially reversed upon ILK depletion, mitigating FA-induced renal damage. The signaling axis composed by ILK, GSK3β, and C/EBPβ regulated CPT1A transcription as the limiting factor in the FA-based impaired mitochondrial activity. We highlight ILK as a potential therapeutical target for preserving mitochondrial function in kidney injury.

A Dual-Channel Fluorescence Probe for Early Diagnosis and Treatment Monitoring of Acute Kidney Injury by Detecting HOCl and Cys with Different Fluorescence Signals

The pathogenesis of acute kidney injury (AKI) is a multifaceted process involving various mechanisms, with oxidative stress playing a crucial role in its development. Hypochlorite (HOCl) and cysteine (Cys) are indicators of oxidative stress in AKI pathophysiology, directly reflecting the degree of oxidative stress and disease severity. However, their exact mechanism of action in AKI pathophysiology remains unknown. Herein, we developed a dual-channel fluorescent probe, MB-NAP, which allowed for the simultaneous detection of HOCl and Cys. The probe exhibited distinct fluorescence responses in the green channel (λex = 450 nm, λem = 560 nm) and red channel (λex = 610 nm, λem = 690 nm), without any spectral crosstalk, allowing for accurate measurement of both analytes. We successfully applied MB-NAP to monitor the levels of HOCl and Cys in cellular and in vivo models of AKI, revealing a significant increase in their concentrations compared to normal models. Furthermore, MB-NAP was demonstrated to exhibit outstanding capabilities for drug screening by effectively real-time monitoring HOCl and Cys. This study not only provides a more sensitive and reliable method/tool for tracking AKI-related pathological processes but also offers a potential breakthrough in the early diagnosis and identification of therapeutic agents aimed at mitigating oxidative stress-induced damage in AKI.

Olesoxime protects against cisplatin-induced acute kidney injury by attenuating mitochondrial dysfunction

BACKGROUND

Mitochondrial dysfunction is a critical factor in the pathogenesis of acute kidney injury (AKI). Agents that ameliorate mitochondrial dysfunction hold potential for AKI treatment. The objective of this study was to investigate the impact of olesoxime, a novel mitochondrial-targeted agent, on cisplatin-induced AKI.

METHODS

In vivo, a cisplatin-induced AKI mouse model was established by administering a single intraperitoneal dose of cisplatin (25 mg/kg) to male C57BL/6 mice for 72 hours, followed by gavage of either olesoxime or a control solution. In vitro, human proximal tubular HK2 cells were cultured and subjected to treatments with cisplatin, either in the presence or absence of olesoxime.

RESULTS

In vivo, our findings demonstrated that olesoxime administration significantly mitigated the nephrotoxic effects of cisplatin in mice, as evidenced by reduced blood urea nitrogen (BUN) and serum creatinine (SCr) levels, improved renal histopathology, and decreased expression of renal tubular injury markers such as kidney injury molecule 1 (KIM-1) and neutrophil gelatinase-associated lipocalin (NGAL). Furthermore, olesoxime administration markedly reduced cisplatin-induced apoptosis, inflammation, and oxidative stress in the kidneys of AKI mice. Additionally, olesoxime treatment effectively restored mitochondrial function in the kidneys of AKI mice. In vitro, our results indicated that olesoxime treatment protected against cisplatin-induced apoptosis and mitochondrial dysfunction in cultured HK2 cells. Notably, cisplatin's anticancer effects were unaffected by olesoxime treatment in human cancer cells.

CONCLUSION

The results of this study suggest that olesoxime is a viable and efficient therapeutic agent in the treatment of cisplatin-induced acute kidney injury presumably by alleviating mitochondrial dysfunction.

SREBP1c-Mediated Transcriptional Repression of YME1L1 Contributes to Acute Kidney Injury by Inducing Mitochondrial Dysfunction in Tubular Epithelial Cells

Acute kidney injury (AKI) is a prevalent clinical syndrome with high morbidity and mortality. Accumulating studies suggest mitochondrial dysfunction as the typical characteristics and key process of AKI, but the underlying mechanism remains elusive. The YME1-like 1 (YME1L1) ATPase, an inner mitochondrial membrane protein, is screened and identified to be downregulated in renal tubular epithelial cells of various mouse models and patients of AKI. Dramatically, restoration of YME1L1 expression significantly alleviates cisplatin-induced AKI and subsequent chronic kidney disease (CKD) through attenuating mitochondrial dysfunction via maintaining optic atrophy 1 (OPA1)-mediated mitochondrial energy metabolism homeostasis. Mechanistically, the upregulated expression of sterol regulatory element binding transcription factor 1c (SREBP1c) is demonstrated to be responsible for cisplatin-mediated transcriptional inhibition of YME1L1 via directly binding to its promoter region. Moreover, cisplatin-induced methyltransferase-like 3 (METTL3)-mediated m6A modification enhances SREBP1c mRNA stability, thereby upregulating its expression. Notably, both depletion of SREBP1c and renal tubule-specific overexpression of YME1L1 markedly ameliorate cisplatin-induced AKI and its transition to CKD. Taken together, these findings suggest that METTL3-mediated SREBP1c upregulation contributes to AKI and its progression to CKD through disrupting mitochondrial energy metabolism via transcriptionally suppressing YME1L1. Targeting the SREBP1c/YME1L1 signaling may serve as a novel therapeutic strategy against AKI.

Ursodeoxycholic acid protects against sepsis-induced acute kidney injury by activating Nrf2/HO-1 and inhibiting NF-κB pathway

BACKGROUND

Ursodeoxycholic acid (UDCA), traditionally recognized for its hepatoprotective effects, has also shown potential in protecting kidney injury. This study aimed to evaluate the protective effects of UDCA against sepsis-induced acute kidney injury (AKI) and to elucidate the underlying mechanisms.

METHODS

Sixty male C57BL/6 N mice were utilized to establish a sepsis-induced AKI model through intravenous injection of lipopolysaccharides (LPS, 10 mg/kg). UDCA (15, 30, and 60 mg/kg) was administered intraperitoneally once daily for 7 days before LPS injection. Kidney injury was evaluated by HE staining and biochemical markers, including serum creatinine (Cr), blood urea nitrogen (BUN), urinary protein, neutrophil gelatinase-associated lipocalin (NGAL), kidney injury molecule-1 (KIM-1), N-acetyl-β-D-glucosaminidase (NAG), and retinol binding protein (RBP). Oxidative stress parameters and nuclear factor erythroid 2-related factor 2 (Nrf2)/ heme oxygenase-1 (HO-1) pathway, pro-inflammatory cytokines and nuclear factor-kappa B (NF-κB) pathway were also evaluated. Additionally, HK-2 cells were treated with LPS in vitro, and cell viability and apoptosis were detected using CCK-8 kit and flow cytometer, respectively.

RESULTS

UDCA significantly attenuated LPS-induced renal histopathological damage and improved renal function, as evidenced by reduction in serum Cr, BUN, and urinary protein levels. UDCA also up-regulated the protein expression of zonula occludens-1 (ZO-1) and Ezrin in the kidney, and reduced the urinary levels of NGAL, KIM-1, NAG, and RBP. Moreover, UDCA inhibited NF-κB p65 phosphorylation and reduced pro-inflammatory cytokines levels (TNF-α, IL-1β, and IL-6) in both serum and kidney. UDCA alleviated oxidative stress by activating the Nrf2/HO-1 pathway in the kidney. In vitro, UDCA reduced LPS-induced cell injury and apoptosis in HK-2 cells, with these protective effects being blocked by the Nrf2 inhibitor ML385.

CONCLUSIONS

Our present study demonstrated that UDCA exerts protective effects against sepsis-induced AKI by attenuating oxidative stress and inflammation, primarily through the activation of the Nrf2/HO-1 pathway and inhibition of the NF-κB pathway. These findings highlight the therapeutic potential of UDCA in preventing sepsis-induced AKI.

Fecal bile acid dysmetabolism and reduced ursodeoxycholic acid correlate with novel microbial signatures in feline chronic kidney disease

Background

Microbial-derived secondary bile acids (SBAs) are reabsorbed and sensed via host receptors modulating cellular inflammation and fibrosis. Feline chronic kidney disease (CKD) occurs with progressive renal inflammation and fibrosis, mirroring the disease pathophysiology of human CKD patients.

Methods

Prospective cross-sectional study compared healthy cats (n = 6) with CKD (IRIS Stage 2 n = 17, Stage 3 or 4 n = 11). Single timepoint fecal samples from all cats underwent targeted bile acid metabolomics. 16S rRNA gene amplicon sequencing using DADA2 with SILVA taxonomy characterized the fecal microbiota.

Results

CKD cats had significantly reduced fecal concentrations (median 12.8 ng/mg, Mann-Whitney p = 0.0127) of the SBA ursodeoxycholic acid (UDCA) compared to healthy cats (median 39.4 ng/mg). Bile acid dysmetabolism characterized by <50% SBAs was present in 8/28 CKD and 0/6 healthy cats. Beta diversity significantly differed between cats with <50% SBAs and > 50% SBAs (PERMANOVA p < 0.0001). Twenty-six amplicon sequence variants (ASVs) with >97% nucleotide identity to Peptacetobacter hiranonis were identified. P. hiranonis combined relative abundance was significantly reduced (median 2.1%) in CKD cats with <50% SBAs compared to CKD cats with >50% SBAs (median 13.9%, adjusted p = 0.0002) and healthy cats with >50% SBAs (median 15.5%, adjusted p = 0.0112). P. hiranonis combined relative abundance was significantly positively correlated with the SBAs deoxycholic acid (Spearman r = 0.5218, adjusted p = 0.0407) and lithocholic acid (Spearman r = 0.5615, adjusted p = 0.0156). Three Oscillospirales ASVs and a Roseburia ASV were also identified as significantly correlated with fecal SBAs.

Clinical and translational importance

The gut-kidney axis mediated through microbial-derived SBAs appears relevant to the spontaneous animal CKD model of domestic cats. This includes reduced fecal concentrations of the microbial-derived SBA UDCA, known to regulate inflammation and fibrosis and be reno-protective. Microbes correlated with fecal SBAs include bai operon containing P. hiranonis, as well as members of Oscillospirales, which also harbor a functional bai operon. Ultimately, CKD cats represent a translational opportunity to study the role of SBAs in the gut-kidney axis, including the potential to identify novel microbial-directed therapeutics to mitigate CKD pathogenesis in veterinary patients and humans alike.

Ursodeoxycholic Acid Platinum(IV) Conjugates as Antiproliferative and Antimetastatic Agents: Remodel the Tumor Microenvironment through Suppressing JAK2/STAT3 Signaling

Tumor microenvironment (TME) is a pivotal factor driving the tumor metastasis and leading to the failure of tumor therapy. Here, a series of ursodeoxycholic acid platinum(IV) conjugates with potency in remodeling the TME through suppressing JAK2/STAT3 signaling was developed. A candidate was screened out, which displayed potent antiproliferative and antimetastatic performance both in vitro and in vivo. It displayed superior pharmacokinetic properties compared to cisplatin. Serious DNA injury was induced, and then mitochondria-mediated apoptosis was initiated through the Bcl-2/Bax/Caspase3 pathway. The JAK2/STAT3 and TGF-β1 signaling pathways were remarkably inhibited, and pro-death autophagy was subsequently promoted. The inflammatory and hypoxic TME was suppressed by downregulating COX-2, MMP9, and HIF-1α, which resulted in inhibited angiogenesis in tumors by inhibiting the HIF-1α/VEGFA axis. Additionally, the immunosuppressive TME was reversed by blocking the immune checkpoint PD-L1, further improving the density of CD3+ and CD8+ tumor-infiltrating lymphocytes, and promoting macrophage polarization from M2- to M1-type.

Insights into the gut-kidney axis and implications for chronic kidney disease management in cats and dogs

Chronic kidney disease (CKD) in cats and dogs presents significant clinical challenges, with emerging research highlighting the pivotal role of the gut-kidney axis in its pathogenesis and management. Gut dysbiosis, characterized by alterations in the gut microbiome composition and function, contributes to microbial dysmetabolism of key nutrients causing uremic toxin accumulation and disruptions in amino acid, bile acid and fatty acid profiles. These disturbances in turn exacerbate renal dysfunction and systemic inflammation. Recent research in veterinary medicine, particularly in cats, supports the gut microbiome and microbial-derived metabolites as novel therapeutic targets. Potential therapeutic strategies targeting the gut microbiome and microbial dysmetabolism, including dietary management, probiotics, adsorbents, and addressing constipation, offer promising avenues for intervention to restore metabolic balance and preserve renal function. This review highlights the microbial influence on renal health and focuses on potential therapeutic strategies available to veterinarians to optimize the management of CKD in cats and dogs.

Further delineation of the phenotypic and metabolomic profile of ALDH1L2-related neurodevelopmental disorder

ALDH1L2, a mitochondrial enzyme in folate metabolism, converts 10-formyl-THF (10-formyltetrahydrofolate) to THF (tetrahydrofolate) and CO2. At the cellular level, deficiency of this NADP+-dependent reaction results in marked reduction in NADPH/NADP+ ratio and reduced mitochondrial ATP. Thus far, a single patient with biallelic ALDH1L2 variants and the phenotype of a neurodevelopmental disorder has been reported. Here, we describe another patient with a neurodevelopmental disorder associated with a novel homozygous missense variant in ALDH1L2, Pro133His. The variant caused marked reduction in the ALDH1L2 enzyme activity in skin fibroblasts derived from the patient as probed by 10-FDDF, a stable synthetic analog of 10-formyl-THF. Additional associated abnormalities in these fibroblasts include reduced NADPH/NADP+ ratio and pool of mitochondrial ATP, upregulated autophagy and dramatically altered metabolomic profile. Overall, our study further supports a link between ALDH1L2 deficiency and abnormal neurodevelopment in humans.

Tiliroside attenuates acute kidney injury by inhibiting ferroptosis through the disruption of NRF2-KEAP1 interaction

BACKGROUND

Ferroptosis, an iron-dependent process that regulates cell death. Emerging evidences suggest that ferroptosis induces acute kidney injury (AKI) progression, and inhibiting ferroptosis provides an effect strategy for AKI treatment. The disruption of the NRF2-KEAP1 protein to protein interaction (PPI) induces NRF2 activation, which provides a promising strategy that can identify new ferroptosis inhibitors. A previous study revealed that tiliroside, a glycosidic flavonoid extracted from Edgeworthia chrysantha Lindl (buds), has anti-neuroinflammatory and neuroprotective effects via NRF2 activation. However, the mechanism through which tiliroside activates NRF2 is unknown, and it remains unclear whether it has protective effects against AKI.

PURPOSE

To investigate whether tiliroside has protective effects against AKI in mice and the associated mechanisms.

METHODS

Possible tiliroside substrates were analyzed using molecular docking. Cisplatin- and ischemia-reperfusion injury (IRI)-induced AKI mouse models and HK2 cells model were constructed to evaluate the protective effects of tiliroside. CRISPR/Cas9 mediated NRF2 knockout HK2 cells were used to verify whether NRF2 mediates tiliroside protective effects.

RESULTS

In vivo, our results showed that tiliroside treatment preserved kidney functions in AKI mice models, as showed by lower levels of serum creatinine (SCr), blood urea nitrogen (BUN), and renal injury markers, including neutrophil gelatinase-associated lipocalin (NGAL) and kidney injury molecule 1 (KIM1), compared with the mice in control groups. In vitro, tiliroside treatment greatly ameliorated cisplatin-induced ferroptosis through NRF2 activation in cultured HK2 cells, as evidenced by the protective effects of tiliroside being greatly blunted after the knockout of NRF2 in HK2 cells. Mechanistic studies indicated that tiliroside promoted NRF2/GPX4 pathway activation and ferroptosis inhibition, perhaps via the disruption of the NRF2-KEAP1 PPI.

CONCLUSION

Together, our results demonstrate that tiliroside may serve as a NRF2-KEAP1 PPI inhibitor and prevents ferroptosis-induced AKI, indicating its potential for clinical AKI treatment.

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.

Isorhamnetin alleviates cisplatin-induced acute kidney injury via enhancing fatty acid oxidation

Cisplatin is an effective chemotherapy drug widely used in the treatment of various solid tumors. However, the clinical usage of cisplatin is limited by its nephrotoxicity. Isorhamnetin, a natural flavanol compound, displays remarkable pharmacological effects, including anti-inflammatory and anti-oxidation. In this study, we aimed to investigate the potential of isorhamnetin in alleviating acute kidney injury induced by cisplatin. In vitro study showed that isorhamnetin significantly suppressed the cytotoxic effects of cisplatin on human tubular epithelial cells. Furthermore, isorhamnetin exerted significantly inhibitory effects on cisplatin-induced apoptosis and inflammatory response. In acute kidney injury mice induced by a single intraperitoneal injection with 20 mg/kg cisplatin, oral administration of isorhamnetin two days before or 2 h after cisplatin injection effectively ameliorated renal function and renal tubule injury. Transcriptomics RNA-seq analysis of the mice kidney tissues suggested that isorhamnetin treatment may protect against cisplatin-induced nephrotoxicity via PGC-1α mediated fatty acid oxidation. Isorhamnetin achieved significant enhancements in the lipid clearance, ATP level, as well as the expression of PGC-1α and its downstream target genes PPARα and CPT1A, which were otherwise impaired by cisplatin. In addition, the protection effects of isorhamnetin against cisplatin-induced nephrotoxicity were abolished by a PGC-1α inhibitor, SR-18292. In conclusion, our findings indicate that isorhamnetin could protect against cisplatin-induced acute kidney injury by inducing PGC-1α-dependent reprogramming of fatty acid oxidation, which highlights the clinical potential of isorhamnetin as a therapeutic approach for the management of cisplatin-induced nephrotoxicity.

PIM1 attenuates cisplatin-induced AKI by inhibiting Drp1 activation

Cisplatin, an effective anti-cancer drug, always causes acute kidney injury (AKI) by inducing mitochondrial damage. PIM1 is a serine/threonine kinase, which has been shown to regulate mitochondrial function. However, the role and mechanisms of PIM1 in cisplatin-induced AKI remain unexplored. This study aimed to investigate the effects of PIM1 in cisplatin-induced AKI and its underlying mechanisms. To established Cisplatin-induced AKI model, mice were given a single intraperitoneal injection(20 mg/kg) and BUMPT cells were treated with cisplatin(20 μM). PIM1 inhibitor AZD1208 was used to inhibit PIM1 and PIM1-experssing adenovirus was used to overexpress PIM1. Drp1 inhibitor P110 and pcDNA3-Drp1K38A were used to inhibit the activation of Drp1 and mitochondrial fission. The indicators of renal function, renal morphology, apoptosis and mitochondrial dysfunction were assessed to evaluate cisplatin-induced nephrotoxicity. We observed that PIM1 was activated in cisplatin-induced AKI in vivo and cisplatin-induced tubular cells injury in vitro. PIM1 inhibition aggravated cisplatin-induced AKI in vivo, while PIM1 overexpression attenuated cisplatin-induced kidney injury in vivo and in vitro. Moreover, inhibiting PIM1 exacerbated mitochondrial damage in mice, but overexpressing PIM1 relieved mitochondrial damage in mice and BUMPT cells. In mice and BUMPT cells, inhibiting PIM1 deregulated the expression of p-Drp1S637, overexpressing PIM1 upregulated the ex-pression of p-Drp1S637. And inhibiting Drp1 activity alleviated cell damage in BUMPT cells with PIM1 knockdown or inhibition. This study demonstrated the protective effect of PIM1 in cisplatin-induced AKI, and regulation of Drp1 activation might be the underlying mechanism. Altogether, PIM1 may be a potential therapeutic target for cisplatin-induced AKI.

Ursodeoxycholic acid alleviates sepsis-induced lung injury by blocking PANoptosis via STING pathway

Acute lung injury (ALI), a progressive lung disease mostly caused by sepsis, is characterized by uncontrolled inflammatory responses, increased oxidative stress, pulmonary barrier dysfunction, and pulmonary edema. Ursodeoxycholic acid (UDCA) is a natural bile acid with various pharmacological properties and is extensively utilized in clinical settings for the management of hepatobiliary ailments. Nonetheless, the potential protective effects and mechanism of UDCA on sepsis-induced lung injuries remain unknown. In this study, we reported that UDCA effectively inhibited pulmonary edema, inflammatory cell infiltration, pro-inflammatory cytokines production, and oxidative stress. Furthermore, UDCA treatment significantly alleviated the damage of pulmonary barrier and enhanced alveolar fluid clearance. Importantly, UDCA treatment potently suppressed PANoptosis-like cell death which is demonstrated by the block of apoptosis, pyroptosis, and necroptosis. Mechanistically, UDCA treatment prominently inhibited STING pathway. And the consequential loss of STING substantially impaired the beneficial effects of UDCA treatment on the inflammatory response, pulmonary barrier, and PANoptosis. These results indicate that STING plays a pivotal role in the UDCA treatment against sepsis-induced lung injury. Collectively, our findings show that UDCA treatment can ameliorate sepsis-induced lung injury and verified a previously unrecognized mechanism by which UDCA alleviated sepsis-induced lung injury through blocking PANoptosis-like cell death via STING pathway.

Umbelliferone attenuates cisplatin-induced acute kidney injury by inhibiting oxidative stress and inflammation via NRF2

In this study, we investigated the nephroprotective effects of Umbelliferone (UMB) against cisplatin-induced acute kidney injury (AKI). C57BL/6J mice were treated with cisplatin via a single intraperitoneal injection (25 mg/kg) with or without UMB (40 mg/kg/day) by gavage. Renal function, apoptosis, oxidative stress, inflammation, and mitochondrial function were analyzed to evaluate kidney injury. In vitro, human proximal tubule epithelial cells were treated with cisplatin, with or without UMB, for 24 h. Western blotting and immunohistochemistry were performed to explore the mechanisms underlying the nephroprotective effects of UMB. Cisplatin-induced renal dysfunction, including increases in blood urea nitrogen, serum creatinine, and renal tubular injury indices (NGAL and KIM-1), were significantly attenuated by UMB treatment, along with renal phenotypic changes and renal tubular injury, as evidenced by improved renal histology. Moreover, NRF2 was activated by UMB pretreatment, along with the inhibition of oxidative stress and inflammatory response, as evidenced by decreased levels of antioxidant genes and inflammatory cytokines in cisplatin-induced AKI. Our results demonstrate that UMB can protect against cisplatin-induced nephrotoxicity, which is mediated by the NRF2 signaling pathway via antioxidant and anti-inflammatory activities, suggesting the clinical potential of UMB for the treatment of AKI.

The biocompatibility and the metabolic impact of thermoresponsive, bile acid-based nanogels on auditory and macrophage cell lines

Deoxycholic acid (DCA), lithocholic acid (LCA), and ursodeoxycholic acid (UDCA) are bile acids that may serve as permeation enhancers when incorporated within the nanogel matrix for drug delivery in the inner ear. In this study, thermoresponsive nanogels were formulated with DCA, LCA and UDCA and their rheological properties and biocompatibility were assessed. The impact of nanogel on cellular viability was evaluated via cell viability assay, the impact of nanogels on cellular bioenergetic parameters was estimated by Seahorse mito-stress test and glycolysis-stress test, while the presence of intracellular free radicals was assessed by reactive oxygen species assay. Nanogels showed a high level of biocompatibility after 24-hour exposure to auditory and macrophage cell lines, with minimal cytotoxicity compared to untreated control. Incubation with nanogels did not alter cellular respiration and glycolysis of the auditory cell line but showed possible mitochondrial dysfunction in macrophages, suggesting tissue-dependent effects of bile acids. Bile acid-nanogels had minimal impact on intracellular reactive oxygen species, with LCA demonstrating the most pro-oxidative behaviour. This study suggests that thermoresponsive nanogels with bile acid, particularly DCA and UDCA, may be promising candidates for inner ear drug delivery.

7-hydroxycoumarin-β-D-glucuronide protects against cisplatin-induced acute kidney injury via inhibiting p38MAPK-mediated apoptosis in mice

AIMS

Cisplatin is a widely-used drug in the clinical treatment of tumors, but kidney nephrotoxicity is one of the reasons that limits its widespread use. We previously found that 7-hydroxycoumarin-β-D-glucuronide (7-HCG) was one of metabolites of skimmin and highly enriched in the kidneys and maintained a high blood concentration in skimmin-treated rats. Therefore, we investigated whether 7-HCG has a protective effect on cisplatin-induced acute kidney injury.

MATERIALS AND METHODS

Male C57BL/6 mice were continuously administered 7-HCG for five days, and on the third day, an intraperitoneal injection of cisplatin was given to induce acute kidney injury. After 72 h, the mice were sacrificed for analysis. Serum and renal tissue were collected for renal function evaluation. RNA sequencing was used to explore mechanism, and further validated by western blot and immunohistochemistry. In addition, pharmacokinetic study of oral 7-HCG administration was performed to examine how much 7-hydroxycoumarin (7-HC) was metabolized and 7-HC possible effect on renal protection.

KEY FINDINGS

7-HCG significantly reduced serum BUN and SCR levels, and alleviated pathological damage in renal tissue, and reduced the renal index. RNA sequencing revealed that 7-HCG could reverse p38 MAPK regulation and apoptosis. By western blotting, it was found that 7-HCG could reduce renal injury by reducing p-p38, p-ERK, p-JNK, cleaved-caspase3 and Bax. The immunohistochemical results of cleaved-caspase3 were consistent with western blotting. 7-HCG also significantly reduced the production of ROS in kidney tissue. Pharmacokinetic experiments have shown that 7-HCG in the blood increased rapidly and was eliminated slowly, with an average t_1/2β of 18.3 h. And the concentration of 7-HCG in the target organ kidney was about 4 times higher than that in blood.

SIGNIFICANCE

Our findings indicate that 7-HCG could exert its protective effect against cisplatin-induced acute kidney injury by inhibiting apoptosis via p38 MAPK regulation and elucidates its pharmacokinetics.

DNA-dependent protein kinase catalytic subunit (DNA-PKcs) drives chronic kidney disease progression in male mice

Kidney injury initiates epithelial dedifferentiation and myofibroblast activation during the progression of chronic kidney disease. Herein, we find that the expression of DNA-PKcs is significantly increased in the kidney tissues of both chronic kidney disease patients and male mice induced by unilateral ureteral obstruction and unilateral ischemia-reperfusion injury. In vivo, knockout of DNA-PKcs or treatment with its specific inhibitor NU7441 hampers the development of chronic kidney disease in male mice. In vitro, DNA-PKcs deficiency preserves epithelial cell phenotype and inhibits fibroblast activation induced by transforming growth factor-beta 1. Additionally, our results show that TAF7, as a possible substrate of DNA-PKcs, enhances mTORC1 activation by upregulating RAPTOR expression, which subsequently promotes metabolic reprogramming in injured epithelial cells and myofibroblasts. Taken together, DNA-PKcs can be inhibited to correct metabolic reprogramming via the TAF7/mTORC1 signaling in chronic kidney disease, and serve as a potential target for treating chronic kidney disease.

Hirsutidin Prevents Cisplatin-Evoked Renal Toxicity by Reducing Oxidative Stress/Inflammation and Restoring the Endogenous Enzymatic and Non-Enzymatic Level

Recent research has shown that phytocomponents may be useful in the treatment of renal toxicity. This study was conducted to evaluate the renal disease hirsutidin in the paradigm of renal toxicity induced by cisplatin. Male Wistar rats were given cisplatin (3 mg/kg body weight/day, for 25 days, i.p.) to induce renal toxicity. Experimental rats were randomly allocated to four different groups: group I received saline, group II received cisplatin, group III received cisplatin + hirsutidin (10 mg/kg)and group IV (per se)received hirsutidin (10 m/kg)for 25 days. Various biochemical parameters were assessed, oxidative stress (superoxide dismutase (SOD), glutathione transferase (GSH), malonaldehyde (MDA) and catalase (CAT)), blood-chemistry parameters (blood urea nitrogen (BUN) and cholesterol), non-protein-nitrogenous components (uric acid, urea, and creatinine), and anti-inflammatory-tumor necrosis factor-α (TNF-α), interleukin-1β(IL-1β). IL-6 and nuclear factor-kB (NFκB) were evaluated and histopathology was conducted. Hirsutidin alleviated renal injury which was manifested by significantly diminished uric acid, urea, urine volume, creatinine, and BUN, compared to the cisplatin group. Hirsutidin restored the activities of several antioxidant enzyme parameters—MDA, CAT, GSH, and SOD. Additionally, there was a decline in the levels of inflammatory markers—TNF-α, IL-1β, IL-6, and NFκB—compared to the cisplatin group. The current research study shows that hirsutidin may act as a therapeutic agent for the treatment of nephrotoxicity induced by cisplatin.

Biological synthesis of ursodeoxycholic acid

Ursodeoxycholic acid (UDCA) is a fundamental treatment drug for numerous hepatobiliary diseases that also has adjuvant therapeutic effects on certain cancers and neurological diseases. Chemical UDCA synthesis is environmentally unfriendly with low yields. Biological UDCA synthesis by free-enzyme catalysis or whole-cell synthesis using inexpensive and readily available chenodeoxycholic acid (CDCA), cholic acid (CA), or lithocholic acid (LCA) as substrates is being developed. The free enzyme-catalyzed one-pot, one-step/two-step method uses hydroxysteroid dehydrogenase (HSDH); whole-cell synthesis, mainly uses engineered bacteria (mainly Escherichia coli) expressing the relevant HSDHs. To further develop these methods, HSDHs with specific coenzyme dependence, high enzyme activity, good stability, and high substrate loading concentration, P450 monooxygenase with C-7 hydroxylation activity and engineered strain harboring HSDHs must be exploited.

Novel function of Roxadustat (FG-4592) as an anti-shock drug in sepsis by regulating mitochondrial oxidative stress and energy metabolism

BACKGROUND

Septic shock is a serious clinical syndrome leading to high mortality. A new anti-anemia drug Roxadustat (FG-4592) protected against cardiac injury and hypertension. However, its effect and mechanism on shock and cardiac dysfunction induced by sepsis require to be investigated.

METHODS

C57BL/6j mice received FG-4592 (10 mg/kg/day) by i.p injection, followed by lipopolysaccharide (LPS) or cecal ligation and puncture (CLP) treatment. Mortality and shock status were monitored during the experiment. Cardiac function was assessed using echocardiography and serum lactate dehydrogenase (LDH) and creatine kinase-MB (CK-MB) assay. TEM, COX-SDH staining and ATP production were used to evaluate mitochondrial function. A non-targeted metabolomic analysis was performed to evaluate the metabolic disorders.

RESULTS

Both pre- and post-treatment of FG-4592 could improve the survival rate in LPS- and CLP-induced sepsis mice with a better effect in pre-treated animals. Meanwhile, FG-4592 improved systolic blood pressure and body temperature drop in septic mice along with alleviated cardiac dysfunction (as shown by the restoration of decreased LVEF and LVFS and increased LDH and CK-MB) and inflammation. Interestingly, we observed that FG-4592 improved mitochondrial oxidative stress possibly by upregulating the anti-oxidative enzymes of SOD2 and HO-1. Furthermore, FG-4592 improved the energy supply and glycerophospholipid metabolism in cardiomyocytes, possibly through upregulating the HIF-1α-targeted genes of LDHA and PDK1 in glycolysis and CHK-α, respectively.

CONCLUSIONS

FG-4592 protected against mortality and shock in septic animals possibly by antagonizing mitochondrial oxidative stress and metabolic disorders.

GENERAL SIGNIFICANCE

This study provides a potential of FG-4592 as a novel drug for treating septic shock.

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.

Ginsenoside Rg1 Ameliorates Acute Renal Ischemia/Reperfusion Injury via Upregulating AMPKα1 Expression

Acute renal ischemia/reperfusion (I/R) injury often occurs during kidney transplantation and other kidney surgeries, and the molecular mechanism involves oxidative stress. We hypothesized that ginsenoside Rg1 (Rg1), a saponin derived from ginseng, would protect the renal tissue against acute renal I/R injury by upregulating 5' adenosine monophosphate-activated protein kinase α1 (AMPKα1) expression and inhibiting oxidative stress. The models of acute anoxia/reoxygenation (A/R) damage in normal rat kidney epithelial cell lines (NRK-52E) and acute renal I/R injury in mice were constructed. The results revealed that pretreatment with 25 μM Rg1 significantly increased NRK-52E viability, decreased lactate dehydrogenase (LDH) activity and apoptosis, suppressed reactive oxygen species generation and oxidative stress, stabilized mitochondrial membrane potential and reduced mitochondria permeability transition pore openness, decreased adenosine monophosphate/adenosine triphosphate ratio, and upregulated the expression of AMPKα1, cytochrome b-c1 complex subunit 2, NADH dehydrogenase (ubiquinone) 1 beta subcomplex subunit 8, and B-cell lymphoma 2, while downregulating BCL2-associated X protein expression. The effects of Rg1 pretreatment were similar to those of pAD/Flag-AMPKα1. After acute renal I/R injury, serum creatinine, blood urea nitrogen, LDH activity, and oxidative stress in renal tissue significantly increased. Rg1 pretreatment upregulated AMPKα1 expression, which protects against acute renal I/R injury by maintaining renal function homeostasis, inhibiting oxidative stress, and reducing apoptosis. Compound C, a specific inhibitor of AMPK, reversed the effects of Rg1. In summary, Rg1 pretreatment upregulated AMPKα1 expression, inhibited oxidative stress, maintained mitochondrial function, improved energy metabolism, reduced apoptosis, and ultimately protected renal tissue against acute renal I/R injury.

TXN inhibitor impedes radioresistance of colorectal cancer cells with decreased ALDH1L2 expression via TXN/NF-κB signaling pathway

Background

Colorectal cancer (CRC) is prevalent worldwide and is often challenged by treatment failure and recurrence due to resistance to radiotherapy. Here, we aimed to identify the elusive underlying molecular mechanisms of radioresistance in CRC.

Methods

Weighted gene co-expression network analysis was used to identify potential radiation-related genes. Colony formation and comet assays and multi-target single-hit survival and xenograft animal models were used to validate the results obtained from the bioinformatic analysis. Immunohistochemistry was performed to examine the clinical characteristics of ALDH1L2. Co-immunoprecipitation, immunofluorescence and flow cytometry were used to understand the molecular mechanisms underlying radioresistance.

Results

Bioinformatic analysis, in vitro, and in vivo experiments revealed that ALDH1L2 is a radiation-related gene, and a decrease in its expression induces radioresistance in CRC cells by inhibiting ROS-mediated apoptosis. Patients with low ALDH1L2 expression exhibit resistance to radiotherapy. Mechanistically, ALDH1L2 interacts with thioredoxin (TXN) and regulates the downstream NF-κB signaling pathway. PX-12, the TXN inhibitor, overcomes radioresistance due to decreased ALDH1L2.

Conclusions

Our results provide valuable insights into the potential role of ALDH1L2 in CRC radiotherapy. We propose that the simultaneous application of TXN inhibitors and radiotherapy would significantly ameliorate the clinical outcomes of patients with CRC having low ALDH1L2.

Maintaining homeostasis of mitochondria and endoplasmic reticulum with NSC228155 alleviates cisplatin-induced acute kidney injury

Acute kidney injury (AKI) is a common complication of hospitalization with high mortality. Approximately 30% of patients receiving cisplatin, the first-line chemotherapy treatment, develop AKI. NSC228155 is a novel compound with potential anti-cancer and anti-bacterial effects. Its therapeutic efficacy in other diseases is unclear. In the present study, we investigated the effect of NSC228155 on cisplatin-induced AKI. The mice were consecutively treated with 2.5 mg/kg of NSC228155 for five days and injected with cisplatin (22 mg/kg) via intraperitoneal injection on day three. NSC228155 strikingly improved the renal function by decreasing the serum creatinine by 52.6% in the cisplatin-induced AKI mice model. Pathologically, NSC228155 profoundly alleviated the tubular damage in Periodic Acid-Schiff staining, and significantly reduced the expression of tubular injury markers and apoptosis in the cisplatin-injured mice kidneys. NSC228155 effectively restored the mitochondrial homeostasis by decreasing damaged mitochondria, activating signals for mitochondrial dynamics and recycling, and corrected mitochondrial dysfunction in ATP production and oxidative stress in the cisplatin model. Transcriptomics and metabolomics analysis on the mice renal cortex suggested that NSC228155 profoundly corrected energy metabolism, especially citrate cycle-related pathways, oxidative stress, and endoplasmic reticulum (ER) stress in the cisplatin-induced AKI kidneys. NSC228155 effectively inhibited ER stress induced by cisplatin or tunicamycin in mice kidneys and HK-2 cells. Co-treatment of NSC228155 with 4-phenylbutyrate or MnTBAP showed a similar therapeutic effect in AKI as the inhibitors or NSC228155 alone did, and corrected the mitochondrial dysfunction and ER stress, respectively, indicating the crosstalk between ER and mitochondria played essential roles in the therapeutic effect of NSC228155 in AKI. Together, these results consistently demonstrated that NSC228155 alleviated cisplatin-induced AKI by restoring the homeostasis in mitochondria and ER, suggesting a therapeutic potential and perhaps a novel strategy for drug discovery.

Management of acute kidney injury in gastrointestinal tumor: An overview

Gastrointestinal tumors remain a global health problem. Acute kidney injury (AKI) is a common complication during the treatment of gastrointestinal tumors. AKI can cause a decrease in the remission rate and an increase in mortality. In this review, we analyzed the causes and risk factors for AKI in gastrointestinal tumor patients. The possible mechanisms of AKI were divided into three groups: pretreatment, intrafraction and post-treatment causes. Treatment and prevention measures were proposed according to various factors to provide guidance to clinicians and oncologists that can reduce the incidence of AKI and improve the quality of life and survival rate of gastrointestinal tumor patients.

Wedelolactone protects against cisplatin-induced nephrotoxicity in mice via inhibition of organic cation transporter 2

The balance of cisplatin uptake and efflux, mediated mainly by organic cation transporter 2 (OCT2) and multidrug and toxin extrusion 1 (MATE1), respectively, determines the renal accumulation and nephrotoxicity of cisplatin. Using transporter-mediated cellular uptake assay, we identified wedelolactone (WEL), a medicinal plant-derived natural compound, is a competitive inhibitor of OCT2 and a noncompetitive inhibitor of MATE1. Wedelolactone showed a selectivity to inhibit OCT2 rather than MATE1. Cytotoxicity studies revealed that wedelolactone alleviated cisplatin-induced cytotoxicity in OCT2-overexpressing HEK293 cells, whereas it did not alter the cytotoxicity of cisplatin in various cancer cell lines. Additionally, wedelolactone altered cisplatin pharmacokinetics, reduced kidney accumulation of cisplatin, and ameliorated cisplatin-induced acute kidney injury in the Institute of Cancer Research mice. In conclusion, these findings suggest a translational potential of WEL as a natural therapy for preventing cisplatin-induced nephrotoxicity and highlight the need for drug-drug interaction investigations of WEL with other treatments which are substrates of OCT2 and/or MATE1.

Protective Effect of 20(R)-Ginsenoside Rg3 Against Cisplatin-Induced Renal Toxicity via PI3K/AKT and NF-[Formula: see text]B Signaling Pathways Based on the Premise of Ensuring Anticancer Effect

Although the protective effect of ginsenoside on cisplatin-induced renal injury has been extensively studied, whether ginsenoside interferes with the antitumor effect of cisplatin has not been confirmed. In this paper, we verified the main molecular mechanism of 20(R)-ginsenoside Rg3 (R-Rg3) antagonizing cisplatin-induced acute kidney injury (AKI) through the combination of in vivo and in vitro models. It is worth mentioning that the two cell models of HK-2 and HepG2 were used simultaneously for the first time to explore the effect of the activation site of tumor-associated protein p53 on apoptosis and tumor suppression. The results showed that a single injection of cisplatin (20 mg/kg) led to weight loss, the kidney index of the mice increased, and creatinine (CRE) and blood urea nitrogen (BUN) levels in mice sharply increased. Continuous administration of R-Rg3 at doses of 10 and 20 mg/kg for 10 days could significantly alleviate this symptom. Similarly, R-Rg3 treatment reduced oxidative stress damage caused by cisplatin. Moreover, R-Rg3 could observably reduce the apoptosis and inflammatory infiltration of renal tubular cells induced by cisplatin. We used western blotting analysis to demonstrate that R-Rg3 restored cisplatin-induced AKI might be related to PI3K/AKT and NF-[Formula: see text]B mediated apoptosis and inflammation pathways. In the meantime, we also verified that R-Rg3 could activate different sites of p53 to control renal cell apoptosis induced by cisplatin without affecting its antitumor effect.

Panax notoginseng saponins reduces the cisplatin-induced acute renal injury by increasing HIF-1α/BNIP3 to inhibit mitochondrial apoptosis pathway

Cisplatin (CDDP) may induce apoptosis of renal tubular epithelial cells (RTEC) and cause CDDP-induced acute kidney injury (CAKI) during cancer treatment, but yet lack of preventive measures and effective treatment. As a new Chinese herbal preparation, Panax notoginseng saponins (PNS) has been found to mitigate CDDP-induced CAKI through elevating the expression of HIF-1α in the rat model, according to the data from our previous works. However, the underlying link between HIF-1α and apoptosis has not been well elucidated. The current study as a follow-up work, was aimed to reveal if PNS improves CAKI through HIF-1α-dependent apoptosis. A stably HIF-1α-knockdown human proximal tubular epithelial cell (HK-2) line was established by transfecting a HIF-1α-siRNA into HK-2 cells. Cell viability, mitochondrial function, cell apoptosis ratio and the expression of apoptosis-associated proteins (Cyt C, Bcl2, Bax, caspases 3) were determined. In order to elucidate the underlying mechanism, the expression of HIF-1α and BNIP3 were assessed. Our results showed that treatment of PNS rescued the cell viability of CDDP-injured HK-2 or HIF-1α-knockdown HK-2 cells, and increased the expression levels of ATP and MMP in HK-2 or HIF-1α-knockdown HK-2 cells which were reduced by CDDP. Moreover, PNS treatment decreased the CDDP or CDDP plus HIF-1α-knockdown-induced elevation of apoptosis and apoptosis-associated protein expressions. These findings demonstrate that PNS reduces CAKI through increasing HIF-1α to inhibit mitochondrial apoptosis pathway. Hence, we suggest PNS as a protective and therapeutic new drug for CDDP treatment of cancers, which might have significant meaning of further research and application potential.

The intravenous administration of skin-derived mesenchymal stem cells ameliorates hearing loss and preserves cochlear hair cells in cisplatin-injected mice: SMSCs ameliorate hearing loss and preserve outer hair cells in mice

Mesenchymal stem cells (MSCs) can be isolated from different tissue origins, such as the bone marrow, the placenta, the umbilical cord, adipose tissues, and skin tissues. MSCs can secrete anti-inflammatory molecules and growth factors for tissue repair and remodeling. However, the ability of skin-derived MSCs (SMSCs) to repair cochlear damage and ameliorate hearing loss remains unclear. Cisplatin is a commonly used chemotherapeutic agent that has the side effect of ototoxicity due to inflammation and oxidative stress. This study investigated the effects of SMSCs on cisplatin-induced hearing loss in mice. Two independent experiments were designed for modeling cisplatin-induced hearing loss in mice, one for chronic toxicity (4 mg/kg intraperitoneal [IP] injection once per day for 5 consecutive days) and the other for acute toxicity (25 mg/kg IP injection once on day one). Three days after cisplatin injection, 1 × 10⁶ or 3 × 10⁶ SMSCs were injected through the tail vein. Data on auditory brain responses suggested that SMSCs could significantly reduce the hearing threshold of cisplatin-injected mice. Furthermore, immunohistochemical staining data suggested that SMSCs could significantly ameliorate the loss of cochlear hair cells, TUNEL-positive cells and cleaved caspase 3-positive cells in cisplatin-injected mice. Neuropathological gene analyses revealed that SMSCs treatment could downregulate the expression of cochlear genes involved in apoptosis, autophagy, chromatin modification, disease association, matrix remodeling, oxidative stress, tissue integrity, transcription, and splicing and unfolded protein responses. Additionally, SMSCs treatment could upregulate the expression of cochlear genes affecting the axon and dendrite structures, cytokines, trophic factors, the neuronal skeleton and those involved in carbohydrate metabolism, growth factor signaling, myelination, neural connectivity, neural transmitter release, neural transmitter response and reuptake, neural transmitter synthesis and storage, and vesicle trafficking. Results from TUNEL and caspase 3 staining further confirmed that cisplatin-induced apoptosis in cochlear tissues of cisplatin-injected mice could be reduced by SMSCs treatment. In conclusion, the evidence of the effects of SMSCs in favor of ameliorating ototoxicity-induced hearing loss suggests a potential clinical application.

Mechanisms of Cisplatin-Induced Acute Kidney Injury: Pathological Mechanisms, Pharmacological Interventions, and Genetic Mitigations

Administration of the chemotherapeutic agent cisplatin leads to acute kidney injury (AKI). Cisplatin-induced AKI (CIAKI) has a complex pathophysiological map, which has been linked to cellular uptake and efflux, apoptosis, vascular injury, oxidative and endoplasmic reticulum stress, and inflammation. Despite research efforts, pharmaceutical interventions, and clinical trials spanning over several decades, a consistent and stable pharmacological treatment option to reduce AKI in patients receiving cisplatin remains unavailable. This has been predominately linked to the incomplete understanding of CIAKI pathophysiology and molecular mechanisms involved. Herein, we detail the extensively known pathophysiology of cisplatin-induced nephrotoxicity that manifests and the variety of pharmacological and genetic alteration studies that target them.

The novel STING antagonist H151 ameliorates cisplatin-induced acute kidney injury and mitochondrial dysfunction

Stimulator of interferon genes (STING) is an important adaptor in cytosolic DNA-sensing pathways. A recent study found that the deletion of STING ameliorated cisplatin-induced acute kidney injury (AKI), suggesting that STING could serve as a potential target for AKI therapy. Up to now, a series of small-molecule STING inhibitors/antagonists have been identified. However, none of the research was performed to explore the role of human STING inhibitors in AKI. Here, we investigated the effect of a newly generated covalent antagonist, H151, which targets both human and murine STING, in cisplatin-induced AKI. We found that H151 treatment significantly ameliorated cisplatin-induced kidney injury as shown by the improvement of renal function, kidney morphology, and renal inflammation. In addition, tubular cell apoptosis and increased renal tubular injury marker neutrophil gelatinase-associated lipocalin induced by cisplatin were also effectively attenuated in H151-treated mice. Moreover, the mitochondrial injury caused by cisplatin was also reversed as evidenced by improved mitochondrial morphology, restored mitochondrial DNA content, and reversed mitochondrial gene expression. Finally, we observed enhanced mitochondrial DNA levels in the plasma of patients receiving platinum-based chemotherapy compared with healthy controls, which could potentially activate STING signaling. Taken together, these findings suggested that H151 could be a potential therapeutic agent for treating AKI possibly through inhibiting STING-mediated inflammation and mitochondrial injury.NEW & NOTEWORTHY Although various stimulator of interferon genes (STING) inhibitors have been identified, no research was performed to investigate the role of human STING inhibitors in AKI. Here, we evaluated the effect of H151 targeting both human and murine STING on cisplatin-induced AKI and observed a protection against renal injury possibly through ameliorating inflammation and mitochondrial dysfunction.

Parkin overexpression alleviates cardiac aging through facilitating K63-polyubiquitination of TBK1 to facilitate mitophagy

Cumulative clinical and experimental evidence has revealed a cardinal role for mitochondrial integrity in cardiac aging. Parkin-mediated mitophagy is essential to ensure mitochondrial quality control in myocardium. This study was designed to examine the impact of Parkin overexpression on aging-induced myocardial anomalies and the underlying mechanisms with a focus on Parkin-regulated mitophagy. Cardiac function, myocardial apoptosis, mitochondrial ultrastructure and mitophagy were examined in young (3 mo) and old (24-26 mo) wild-type (WT) and Parkin transgenic mice. Our data revealed compromised myocardial function and mitochondrial morphology along with overtly apoptosis with advanced aging, the effects of which were attenuated by Parkin overexpression. Advanced aging dampened mitophagy as evidenced by decreased levels of Parkin, LC3II, phosphorylation of p62 and TBK1 in isolated mitochondria as well as reduced mitochondria autophagosomes, the effects of which were mitigated by restoration of mitophagy via Parkin overexpression. Using the low-dose doxorubicin (DOX) in vitro model of cell senescence, we noted that Parkin-offered beneficial effect against senescence was abolished by the TBK1 kinase inhibitor BX795. With TBK1 overexpression in cardiomyocytes, we uncovered the interaction of Parkin with TBK1 using a Co-immunoprecipitation (Co-IP) assay. The interaction of Parkin with TBK1 contributed to K63-linked polyubiquitination of TBK1. Our study also noted that DOX disturbed K63-linked polyubiquitination of TBK1 with downregulation of Parkin. Parkin overexpression promoted K63-linked polyubiquitination of TBK1 through Lys30 and Lys401 residues to foster TBK1 phosphorylation to facilitate efficient mitophagy. In summary, these findings suggested that Parkin effectively rescued cardiac aging through promoting K63-linked polyubiquitination of TBK1 to facilitate mitophagy.

Inhibition of ROCK2 alleviates renal fibrosis and the metabolic disorders in the proximal tubular epithelial cells

Non-specific inhibition of Rho-associated kinases (ROCKs) alleviated renal fibrosis in the unilateral ureteral obstruction (UUO) model, while genetic deletion of ROCK1 did not affect renal pathology in mice. Thus, whether ROCK2 plays a role in renal tubulointerstitial fibrosis needs to be clarified. In the present study, a selective inhibitor against ROCK2 or genetic approach was used to investigate the role of ROCK2 in renal tubulointerstitial fibrosis. In the fibrotic kidneys of chronic kidney diseases (CKDs) patients, we observed an enhanced expression of ROCK2 with a positive correlation with interstitial fibrosis. In mice, the ROCK2 protein level was time-dependently increased in the UUO model. By treating CKD animals with KD025 at the dosage of 50 mg/kg/day via intraperitoneal injection, the renal fibrosis shown by Masson's trichrome staining was significantly alleviated along with the reduced expression of fibrotic genes. In vitro, inhibiting ROCK2 by KD025 or ROCK2 knockdown/knockout significantly blunted the pro-fibrotic response in transforming growth factor-β1 (TGF-β1)-stimulated mouse renal proximal tubular epithelial cells (mPTCs). Moreover, impaired cellular metabolism was reported as a crucial pathogenic factor in CKD. By metabolomics analysis, we found that KD025 restored the metabolic disturbance, including the impaired glutathione metabolism in TGF-β1-stimulated tubular epithelial cells. Consistently, KD025 increased antioxidative stress enzymes and nuclear erythroid 2-related factor 2 (Nrf2) in fibrotic models. In addition, KD025 decreased the infiltration of macrophages and inflammatory response in fibrotic kidneys and blunted the activation of macrophages in vitro. In conclusion, inhibition of ROCK2 may serve as a potential novel therapy for renal tubulointerstitial fibrosis in CKD.