INTRODUCTION:Renal fibrosis as a common pathological endpoint in chronic kidney disease (CKD) and end-stage renal disease (ESRD) is a serious threat to patients' life and health. In recent years, the link between epigenetic modifications and renal fibrosis has been increasingly discovered. OBJECTIVES:This study aimed to investigate the effects of the deubiquitinating enzyme OTUD7B on renal fibrosis and its underlying mechanism. METHODS:Transcriptome sequencing of control and fibrotic cells were performed to screen for deubiquitinating enzymes, and the expression of these enzymes were validated in cellular models, animal models, and clinical specimens. The specific role of OTUD7B in renal fibrosis was elucidated through knockdown and overexpression experiments. Subsequently, IP-MS was employed to identify OTUD7B downstream targets, confirming its interaction with PRDX1 and detecting PRDX1 ubiquitination levels and sites. Finally, IP and UbiBrowser were used to predicte SMURF1 as the PRDX1 ubiquitin ligase. Detection of ubiquitination levels and sites revealed that OTUD7B and SMURF1 maintained PRDX1 protein stability together. RESULTS:The reduction of renal fibrosis deubiquitinating enzyme, OTUD7B, was identified by RNA sequencing and validated in cellular, animal and human samples. In addition, its function was verified by knockdown and overexpression of OTUD7B, with overexpression attenuating renal fibrosis and knockdown exacerbating it. Mechanistically, through reducing SMURF1-mediated K63-linked ubiquitination and subsequent lysosomal degradation of PRDX1, OTUD7B elevated PRDX1 expression, resulting in attenuation of renal fibrosis. CONCLUSION:Collectively, targeting the OTUD7B-SMURF1-PRDX1 axis may offer a promising therapeutic approach for renal fibrosis.

The global incidence of diabetes mellitus (DM) is rapidly rising, and DM worsens renal ischemia/reperfusion (I/R) injury, a major cause of high-mortality acute kidney injury (AKI). Therefore, preventing renal I/R injury in DM is crucial. Platycodin D (PD), a compound from Platycodon grandiflorum roots, is known to activate AMP-activated protein kinase (AMPK). Numerous studies have demonstrated that AMPK activation has protective effects in diabetes mellitus (DM) and ischemia/reperfusion (I/R) injury. However, the impact of PD on renal I/R injury in DM and its underlying mechanisms remain unclear. Our experiments revealed that PD treatment via gavage significantly alleviated kidney tissue damage and cell apoptosis in diabetic renal I/R injury. Additionally, PD reduced reactive oxygen species (ROS) levels, and transmission electron microscopy (TEM) indicated a notable discovery in mitophagosome formation. The expression levels of P-AMPK, light chain 3B (LC3B)-II, PTEN-induced putative protein kinase 1 (PINK1) and Parkin all increased under PD treatment, while sequestosome 1 (P62) level decreased. Importantly, AMPK antagonist Compound C (CC) abolished these effects. Additionally, our transcriptomic profiling revealed that PD treatment significantly suppressed MAPK/NF-κB signaling activation. Through functional rescue experiments, we mechanistically demonstrated that PD-mediated AMPK phosphorylation governs this regulatory axis. AMPK inhibition abolished PD's effects on both MAPK/NF-κB suppression, establishing AMPK activation as the upstream modulator. Overall, PD may reduce renal I/R injury in DM through AMPK/PINK1/Parkin-mediated mitophagy and inhibiting MAPK/NF-κB pathway.

Introduction Diabetic renal ischemia-reperfusion injury (RIRI) is a severe surgical complication with particularly poor outcomes in diabetic patients. The histone methyltransferase G9a has been implicated in various pathological processes, but its role in diabetic RIRI remains unclear. Emerging evidence suggests that non-histone protein methylation may play crucial roles in cellular responses to ischemic injury. Objectives This study aimed to investigate the functional role of G9a in diabetic RIRI and elucidate its molecular mechanisms, with particular focus on its regulation of FoxO3a stability, oxidative stress and cellular pyroptosis. Methods We established diabetic RIRI models using G9a conditional knockout mice and HK-2 cells under high glucose conditions. Renal function was assessed through serum creatinine and BUN measurements. Histopathological evaluation and molecular analyses were performed to examine tissue damage and pyroptosis markers. Mechanistic studies included mass spectrometry identification of G9a-interacting proteins, co-immunoprecipitation to verify protein interactions, and ubiquitination assays to characterize post-translational modifications. Site-directed mutagenesis was employed to identify critical residues in FoxO3a regulation. Results G9a expression was significantly upregulated in diabetic RIRI models. Genetic ablation of G9a attenuated renal injury and reduced oxidative stress and pyroptosis in both in vivo and in vitro models. Mechanistically, G9a directly interacted with and methylated FoxO3a at lysine 262, which facilitated its recognition by the E3 ubiquitin ligase TRIM21. TRIM21 subsequently mediated K48-linked polyubiquitination of FoxO3a at lysine 176, leading to proteasomal degradation. This G9a-mediated FoxO3a degradation promoted oxidative stress, NLRP3 inflammasome activation and pyroptosis. Importantly, pharmacological inhibition of G9a with BIX-01294 or FoxO3a overexpression significantly ameliorated diabetic RIRI. Conclusion Our study reveals a novel G9a-TRIM21-FoxO3a regulatory axis in diabetic RIRI, where G9a-mediated methylation licenses FoxO3a ubiquitination and degradation, thereby promoting pyroptosis and oxidative stress. These findings identify G9a as a potential therapeutic target for preventing or treating diabetic kidney ischemia-reperfusion injury.

BACKGROUND: Chronic kidney disease (CKD) is characterized by progressive renal fibrosis, which contributes to disease progression and ultimately leads to kidney failure. Circular RNAs (circRNAs) are key regulators in various fibrotic diseases, showing different expression patterns in different organs. However, the exact role and mechanisms of circRNAs in renal fibrosis are still not fully understood. METHODS: We analyzed circRNA expression in kidney tissues from unilateral ureteral obstruction (UUO) mice using RNA sequencing (RNA-seq). Bioinformatics analysis identified a significant downregulation of circG6pc in fibrotic kidneys. The role and mechanisms by which circG6pc inhibits renal fibrosis were explored both in vivo and in vitro. To further validate our findings, we employed gene overexpression and knockdown, along with immunohistochemistry, dual-luciferase reporter assays, RNA antisense purification (RAP) assays, RNA immunoprecipitation (RIP) assays, western blotting, and RT-qPCR. RESULTS: CircG6pc is significantly downregulated in fibrotic kidneys, and overexpression of circG6pc can notably improve renal fibrosis, mitochondrial dysfunction, and oxidative stress damage. Mechanistically, circG6pc acts as a sponge, directly binding to miR-7018-5p, thereby relieving its inhibitory effect on Aldh6a1 expression. The upregulation of Aldh6a1 promotes mitochondrial biogenesis, corrects mitochondrial dynamics imbalance, alleviates oxidative stress induced by mitochondrial dysfunction, and ultimately suppresses the progression of renal fibrosis. CONCLUSIONS: These findings reveal the molecular mechanism by which circG6pc alleviates mitochondrial dysfunction and oxidative stress through the miR-7018-5p/Aldh6a1 axis, thereby inhibiting renal fibrosis. This provides a potential new strategy for the treatment of progressive CKD.

Kidney renal clear cell carcinoma (KIRC) is recognized as an immunogenic tumor, and immunotherapy is incorporated into its treatment landscape for decades. The acquisition of a tumor mesenchymal phenotype through epithelial-to-mesenchymal transition (EMT) is associated with immune evasion and can contribute to immunotherapy resistance. Here, the involvement of STAM Binding Protein Like 1 (STAMBPL1) is reported in the development of mesenchymal and immune evasion phenotypes in KIRC cells. Mechanistically, STAMBPL1 elevated protein abundance and surface accumulation of TAM Receptor AXL through diminishing the TRIM21-mediated K63-linked ubiquitination and subsequent lysosomal degradation of AXL, thereby enhancing the expression of mesenchymal genes while suppressing chemokines CXCL9/10 and HLA/B/C. In addition, STAMBPL1 enhanced PD-L1 transcription via facilitating nuclear translocation of p65, and knockdown (KD) of STAMBPL1 augmented antitumor effects of PD-1 blockade. Furthermore, STAMBPL1 silencing and the tyrosine kinase inhibitor (TKI) sunitinib also exhibited a synergistic effect on the suppression of KIRC. Collectively, targeting the STAMBPL1/TRIM21/AXL axis can decrease mesenchymal phenotype and potentiate anti-tumor efficacy of cancer therapy.

Long non-coding RNAs (lncRNAs), typically more than 200 nt long, cannot encode proteins, but can regulate gene expression. They play an indispensable role in the occurrence and progression of various cancers. The main purpose of this study is to discuss the role and mechanism of LNC-565686 in prostate cancer. First, we found an increased expression of LNC-565686 in prostate cancer cells using RNA sequencing, which was further verified using qRT-PCR. Then, catRAPID was used to find that LNC-565686 might regulate SND1. Furthermore, a protein half-life experiment was performed to verify that LNC-565686 could stabilize the expression of SND1. In order to further explore the effects of LNC-565686 and SND1 on prostate cancer cells, we knocked down LNC-565686 and SND1 in prostate cancer cells, and verified using CCK8 and flow cytometry and western blot for the detection of apoptosis-related indicators. Collectively, we have found that LNC-565686 can promote the proliferation of prostate cancer cells and inhibit apoptosis by stabilizing the expression of SND1. Therefore, targeting LNC-565686 might be a new treatment for prostate cancer.

Background: Prostate cancer (PC) is one of the most commonly diagnosed cancer in men worldwide. Epithelial-mesenchymal transition (EMT) is considered to play a crucial role in the development of the metastatic castration-resistant prostate cancer, which causes the majority of the death cases in PC. Golgi membrane protein 1 (GOLM1) is highly expressed in PC and has been identified as a driver factor for EMT in various cancers. However, its biological functions and underlying mechanisms remain ambiguous in PC. Method: GOLM1 expression level of PC was detected by Western blot and immunohistochemistry analyses. To investigate GOLM1 functions in cancer cells, we overexpressed and knocked down GOLM1 in different prostate cancer cell lines. Transwell assay and wound healing assay were used to determine the role of GOLM1 in cell EMT, such as migration and invasion abilities. TGF-β1/Smad2 signaling pathway downstream of GOLM1 was detected by Western blot and Transwell assay. Result: GOLM1 expression is up-regulated in PC and correlated with a worse prognosis. GOLM1 promotes the abilities of migration and invasion in PC cell lines (DU145 and LNCaP). Furthermore, TGF-β1/Smad2 signaling is positively regulated by GOLM1 to facilitate EMT in PC, whereas this role can be restored by TGF-β1 after GOLM1 knockdown or be abrogated by p-Smad inhibitor SB431542. Conclusion: GOLM1 is significantly upregulated in PC and acts as a critical oncogene by promoting PC cell EMT process by activating TGF-β1/Smad2 signaling pathway. Therefore, GOLM1 has the potential to be a biomarker for PC diagnosis and to predict the prognosis of PC patients. It is of great significance to seek effective and specific inhibitor of GOLM1 for PC treatment as well.

Prostate cancer (PCa) is the most common cancer in men and the fifth leading cause of cancer death worldwide. Unfortunately, castration-resistant prostate cancer (CRPCa) is incurable with surgical treat and prone to drug resistance. Therefore, it is of great importance to find a new target for treatment. LSD1 is up-regulated in PCa and related with prognosis. The high-expression LSD1 has been shown to be a potential target for treatment and is widely studied for its demethylase-activity. However, its demethylation-independent function remains to be elusive in PCa. Recent study shows that LSD1 can destabilize cancer suppressor protein FBXW7 without demethylation-function. Hence, we hope to investigate the impact of non-canonical function of LSD1 on PCa cell survival. We over-expressed FBXW7 gene through plasmid vector in LNCaP and PC3 cell lines and the result shows that up-regulated FBXW7 can suppress the viability of PC cell through suppressing oncoproteins, such as c-MYC, NOTCH-1. After FBXW7 function experiment on PC cell, we knock-down LSD1 gene in the same kinds of cell lines. In western blot assay, we detected that down-regulation of LSD1 will cause the increasing of FBXW7 protein level and decreasing of its targeting oncoproteins. And mRNA level of FBXW7 did not change significantly after LSD1 knock-down, which means LSD1 may destabilize FBXW7 by protein-protein interactions. Moreover, exogenous wild type LSD1 and catalytically deficient mutant K661A both can abrogate previous effect of LSD1 knock-down. Consequently, LSD1 may promote PC cell survival by destabilizing FBXW7 without its demethylase-activity. Next, we compared two kinds inhibitors, and found that SP-2509 (Allosteric inhibitor) treatment suppress the cancer cell survival by blocking the LSD1–FBXW7 interaction, which is an effect that GSK-2879552 (catalytic inhibitor) cannot achieve. This work revealed a pivotal function of LSD1 in PCa, and indicated a new direction of LSD1 inhibitor research for PCa treatment.

组蛋白赖氨酸特异性去甲基化酶1(LSD1)可以特异性去除组蛋白H3第4、第9位赖氨酸上的单、双甲基,从而调节基因转录.通过去甲基化作用,LSD1参与人类体内多种细胞活动,如细胞增殖、上皮间质转化、自噬等.越来越多的研究表明,其异常表达与多种癌症和其他疾病的发生发展及不良预后相关,而且LSD1是其中关键的调控因子.因此,一系列针对LSD1的药物正在进行临床试验研究.然而,这些抑制剂大多以阻断其脱甲基酶活性为基础.最近的研究表明,LSD1还参与了一系列蛋白质间相互作用,且与其去甲基化作用无关.这极大地扩展了LSD1的生物学作用范围,也为LSD1抑制剂的设计提供了新的思路和方向.本文将对LSD1功能最新的研究进展进行综述,并对其应用前景进行展望.