The SIRT6/BAP1/xCT signaling axis mediates ferroptosis in cisplatin-induced AKI.

Cisplatin is extensively utilized in clinical settings for treating solid tumors; However, its use is restricted because of the kidney damage caused by side effects. Moreover, currently, no effective medications have been approved to prevent or treat acute kidney injury induced by cisplatin. Our research indicates that sirtuin 6 (SIRT6) can inhibit ferroptosis induced by cisplatin, and the use of SIRT6 agonists can alleviate acute kidney injury caused by cisplatin. An animal model of cisplatin-induced acute kidney injury (AKI) was established, followed by RNA sequencing to identify potential differentially expressed genes (DEGs) and associated pathways. To explore the role of SIRT6 in this model, SIRT6 knockout mice were generated, and recombinant adeno-associated virus was employed to achieve SIRT6 overexpression in the mice. In vitro, cells were cultured in a cisplatin-containing medium to establish a cisplatin-induced cell model. The function of SIRT6 was further investigated by overexpressing or knocking down the gene using lentiviral plasmids. To elucidate the underlying molecular mechanisms, we employed RNA sequencing, performed bioinformatics analyses, and conducted chromatin immunoprecipitation assays. RNA sequencing and Western blot analyses revealed a significant reduction in SIRT6 expression in mice with cisplatin-induced acute kidney injury (AKI). Enhancing SIRT6 expression improved renal function, reduced ferroptosis, and mitigated kidney damage, whereas SIRT6 knockout exacerbated kidney injury and heightened ferroptosis. Mechanistically, RNA sequencing, bioinformatics analysis, and chromatin immunoprecipitation assays demonstrated that SIRT6 inhibits ferroptosis by reducing the acetylation of histone H4K9ac at the BAP1 promoter. Furthermore, in vitro studies demonstrated that the SIRT6 agonist UBCS039 can alleviate cisplatin-induced acute kidney injury, highlighting its potential therapeutic role in mitigating cisplatin's damaging effects. However, further research is needed to fully elucidate the underlying mechanisms and to validate these findings in vivo. Our findings underscore the critical role of the SIRT6/BAP1/xCT axis in regulating ferroptosis, particularly via the downregulation of SIRT6, in the context of cisplatin-induced acute kidney injury (AKI). This suggests that SIRT6 could be a promising therapeutic target for treating cisplatin-induced AKI. However, additional research is required to explore the specific mechanisms and fully assess the therapeutic potential of SIRT6 in this context.

Yang S ，Chen L ，Din S ，Ye Z ，Zhou X ，Cheng F ，Li W ... -  《-》

The SP1/SIRT1/ACLY signaling axis mediates fatty acid oxidation in renal ischemia-reperfusion-induced renal fibrosis.

Renal ischemia-reperfusion is the primary cause of acute kidney injury (AKI). Clinically, most patients who experience ischemia-reperfusion injury eventually progress gradually to renal fibrosis and chronic kidney disease (CKD). However, the underlying mechanism for AKI to CKD transition remain absent. Our study demonstrated that the downregulation of sirtuin 1 (Sirt1)-mediated fatty acid oxidation (FAO) facilitates IRI-induced renal fibrosis. The IRI animal model was established, and ribonucleic acid (RNA) sequencing was used to explore potential differentially expressed genes (DEGs) and pathways. The SIRT1 knockout mice were generated, and a recombinant adeno-associated virus that overexpresses SIRT1 was injected into mice to explore the function of SIRT1 in renal fibrosis induced by renal IRI. In vitro, hypoxia/reoxygenation (H/R) was used to establish the classical model of renal IRI and overexpression or knockdown of SIRT1 to investigate the SIRT1 function through lentiviral plasmids. The underlying molecular mechanism was explored through RNA sequencing, bioinformatics analysis, and chromatin immunoprecipitation assay. RNA sequencing analysis and western blot demonstrated that the expression of SIRT1 was significantly decreased in IRI mice. Overexpression of SIRT1 improved renal function and reduced lipid deposition and renal fibrosis. On the contrary, knockout of SIRT1 aggravated kidney injury and renal fibrosis. RNA sequencing, bioinformatics analysis, and chromatin immunoprecipitation assay mechanistically revealed that SIRT1 impairs the acetylation of histone H3K27 on the promoter region of ACLY, thereby impeding FAO activity and promoting renal fibrosis. Additionally, SP1 regulated FAO by directly modulating SIRT1 expression. Our findings highlight that downregulation of SIRT1-modulated FAO facilitated by the SP1/SIRT1/ACLY axis in the kidney increases IRI, suggesting SIRT1 to be a potential therapeutic target for renal fibrosis induced by renal IRI.

Wu H ，Wang L ，Kang P ，Zhou X ，Li W ，Xia Z ... -  《-》

Bergenin inhibits ferritinophagy and ferroptosis in cisplatin-induced acute kidney injury by activating the p-GSK3β/Nrf2/PPARγ pathway.

Ferroptosis plays a key role in cisplatin-induced acute kidney injury (AKI). Bergenin, which is extracted from Ardisiae Japonicae Herba and has long been used in folk tea and herbal tea drinks, is known to activate Nrf2 and has anti-inflammatory and antioxidant properties, however, its protective influence on CI-AKI has not been elucidated. We used models of cisplatin-induced nephrotoxicity in vitro and CI-AKI models in vivo. In vitro, we found that ferroptosis and ferritinophagy biomarkers were strongly regulated by bergenin treatment. Mechanistic experiments demonstrated that bergenin bound to and phosphorylated GSK3β, which inhibited its activity, to promote the nuclear translocation of Nrf2 and its subsequent binding to the PPARγ promoter sequence to activate PPARγ. However, the protective effects of bergenin on ferroptosis and ferritinophagy in cisplatin-exposed HK-2 cells were diminished when Nrf2 or PPARγ was inhibited. In vivo, bergenin effectively inhibited renal damage induced by cisplatin. Furthermore, bergenin attenuated ferritinophagy-mediated ferroptosis caused by cisplatin; these effects were abolished in Nrf2 knockout mice. Our findings revealed that bergenin effectively protected against ferritinophagy and ferroptosis in CI-AKI, which was largely dependent on the activation of the p-GSK3β/Nrf2/PPARγ pathway.

Hu J ，Zhang Y ，Zhang Y ，Shi N ，Miu Y ，Huang J ，Miao M ，Ci X ... -  《-》

Yi-Qi-Jian-Pi-Xiao-Yu formula inhibits cisplatin-induced acute kidney injury through suppressing ferroptosis via STING-NCOA4-mediated ferritinophagy.

The kidneys are the primary excretory organs for platinum drugs, making them susceptible to damage from these drugs. Cisplatin-induced acute kidney injury (CIAKI) is the most common side effect observed in patients undergoing clinical cisplatin treatment. A traditional Chinese medicinal preparation, the Yi-Qi-Jian-Pi-Xiao-Yu formula (YQJPXY), which is a modified formulation of the classical Chinese medicine formula Buyang Huanwu Decoction, has long been used in the treatment of clinical kidney diseases. It is expected to be used to ameliorate cisplatin-induced acute kidney injury. However, the mechanism of this YQJPXY for the treatment of cisplatin-induced acute kidney injury remains unclear. The objective of this study is to examine the impact of the YQJPXY on the inhibition of ferroptosis in cisplatin-induced acute kidney injury and to elucidate the underlying mechanisms. The active components of YQJPXY were analysed using UPLC-MS/MS. A comprehensive investigation was conducted to elucidate the effects and regulatory mechanisms of YQJPXY on CIAKI and ferroptosis in mice subjected to acute cisplatin treatment and in mice receiving cisplatin treatment after STING expression was inhibited using the STING inhibitor C176. The renoprotective effect of YQJPXY on cisplatin-treated mice was evaluated by measuring tissue damage, inflammation and pro-fibrosis. In addition, we employed network pharmacology and molecular docking methodologies to analyse the principal regulatory targets of YQJPXY. Furthermore, the expression of key proteins and markers of ferroptosis and iron metabolism, as well as the levels of key indicators related to STING-associated ferritinophagy, were examined by immunoblotting, immunohistochemistry, immunoprecipitation, quantitative real-time PCR (qPCR) and specific probes. The results demonstrated that YQJPXY reduced the levels of indicators of injury, inflammation and pro-fibrosis in CIAKI mice, with renoprotective effects. Network pharmacological analyses revealed that ferroptosis might be the main biological process regulated by YQJPXY. Furthermore, molecular docking results indicated that STING might be a potential regulatory target of YQJPXY. Furthermore, YQJPXY treatment resulted in a significant reduction in MDA and 4-HNE levels, as well as the inhibition of ferroptosis and improvement in iron metabolic processes. Concomitantly, YQJPXY exhibited a robust protective effect on ferroptosis and iron metabolism homeostasis, as evidenced by its inhibitory action on ferritinophagy. Validation experiments utilising the cisplatin inhibitor C176 demonstrated that YQJPXY inhibits cisplatin-induced ferroptosis in kidney via STING-mediated ferritinophagy. These suggest that YQJPXY alleviates cisplatin-induced acute kidney injury through suppressing ferroptosis via STING-NCOA4-mediated Ferritinophagy.

Zhu J ，Yuan A ，Le Y ，Chen X ，Guo J ，Liu J ，Chen H ，Wang CY ，Lu D ，Lu K ... -  《-》

NDUFS3 alleviates oxidative stress and ferroptosis in sepsis induced acute kidney injury through AMPK pathway.

In recent years, ferroptosis has been found to play an important role in various acute kidney injury (AKI). However, relatively little research has been conducted on sepsis-induced acute kidney injury (SI-AKI). As an important trigger of ferroptosis, how mitochondrial damage plays a regulatory role in SI-AKI is still unclear. To explore the potential relationship between mitochondria and ferroptosis, we established a SI-AKI rat model by intraperitoneal injection of lipopolysaccharide (LPS). Transcriptome sequencing was used to detect changes in gene transcription levels in the control group, LPS 3 h group, LPS 6 h group and LPS 12 h group. The severity of kidney injury was determined based on serum creatinine (CRE), blood urea nitrogen (BUN), tissue HE staining, TUNEL staining and inflammatory factor levels. Cytoscape software was utilized to screen several mitochondria-related HUB genes, and NADH dehydrogenase [ubiquinone] ferrithionein 3 (NDUFS3) was selected for subsequent validation due to its novelty and feasibility. qRT-PCR, Western blot was employed to evaluate the expression of NDUFS3 in kidney tissues. GO enrichment analysis revealed that up-regulated genes in the LPS 12 h group were enriched in several cell death terms while down-regulated genes were enriched in lipid metabolic process and oxidation-reduction progress terms. Furthermore, Western blot, IHC, MDA, GSH and iron content levels were used to assess ferroptosis in the kidney tissue of the SI-AKI rats, dihydroethidium (DHE) assay and ATP kit were used to assess mitochondrial ROS levels and mitochondrial function. To further validate the function of NDUFS3, we constructed overexpression rats using hydrodynamic method by tail vein injection of pc DNA3.1-NDUFS3 overexpression plasmid. we utilized LPS to stimulate HK-2 cells and establish an in vitro model. We then overexpressed NDUFS3 using pcDNA 3.1. The overexpression of NDUFS3 was found to inhibit LPS-induced ferroptosis and mitochondrial damage in HK-2 cells, as evidenced by Western blot, MDA, GSH, divalent iron, ROS levels, Mitosox red, ATP content and transmission electron microscopy. Finally, the use of Compound C to inhibit AMPK in HK-2 cells demonstrated that NDUFS3 plays a protective role through the AMPK pathway. Therefore, our study supports the emerging role of NDUFS3 in SI-AKI, providing new potential mitochondria-related targets for the treatment of SI-AKI.

Wang Y ，Lv W ，Ma X ，Diao R ，Luo X ，Shen Q ，Xu M ，Yin M ，Jin Y ... -  《-》