Hydralazine represses Fpn ubiquitination to rescue injured neurons via competitive binding to UBA52

A major impedance to neuronal regeneration after peripheral nerve injury (PNI) is the activation of various programmed cell death mechanisms in the dorsal root ganglion. Ferroptosis is a form of programmed cell death distinguished by imbalance in iron and thiol metabolism, leading to lethal lipid peroxidation. However, the molecular mechanisms of ferroptosis in the context of PNI and nerve regeneration remain unclear. Ferroportin (Fpn), the only known mammalian nonheme iron export protein, plays a pivotal part in inhibiting ferroptosis by maintaining intracellular iron homeostasis. Here, we explored in vitro and in vivo the involvement of Fpn in neuronal ferroptosis. We first delineated that reactive oxygen species at the injury site induces neuronal ferroptosis by increasing intracellular iron via accelerated UBA52-driven ubiquitination and degradation of Fpn, and stimulation of lipid peroxidation. Early administration of the potent arterial vasodilator, hydralazine (HYD), decreases the ubiquitination of Fpn after PNI by binding to UBA52, leading to suppression of neuronal cell death and significant acceleration of axon regeneration and motor function recovery. HYD targeting of ferroptosis is a promising strategy for clinical management of PNI.

Role of deubiquitinase JOSD2 in the pathogenesis of esophageal squamous cell carcinoma

BACKGROUND Esophageal squamous cell carcinoma(ESCC)is a deadly malignancy with limited treatment options.Deubiquitinases(DUBs)have been confirmed to play a crucial role in the development of malignant tumors.JOSD2 is a DUB involved in con-trolling protein deubiquitination and influencing critical cellular processes in cancer.AIM To investigate the impact of JOSD2 on the progression of ESCC.METHODS Bioinformatic analyses were employed to explore the expression,prognosis,and enriched pathways associated with JOSD2 in ESCC.Lentiviral transduction was utilized to manipulate JOSD2 expression in ESCC cell lines(KYSE30 and RESULTS )Preliminary research indicated that JOSD2 was highly expressed in ESCC tissues,which was associated with poor prognosis.Further analysis demonstrated that JOSD2 was upregulated in ESCC cell lines compared to normal esophageal cells.JOSD2 knockdown inhibited ESCC cell activity,including proliferation and colony-forming ability.Moreover,JOSD2 knockdown decreased the drug resistance and migration of ESCC cells,while JOSD2 overexpression enhanced these phenotypes.In vivo xenograft assays further confirmed that JOSD2 promoted tumor proliferation and drug resistance in ESCC.Mechanistically,JOSD2 appears to activate the MAPK/ERK and PI3K/AKT signaling pathways.Mass spectrometry was used to identify crucial substrate proteins that interact with JOSD2,which identified the four primary proteins that bind to JOSD2,namely USP47,IGKV2D-29,HSP90AB1,and PRMT5.CONCLUSION JOSD2 plays a crucial role in enhancing the proliferation,migration,and drug resistance of ESCC,suggesting that JOSD2 is a potential therapeutic target in ESCC.

Systematic analysis of DNA polymerases as therapeutic targets in pan-cancers

Introduction:DNA polymerases are crucial for maintaining genome stability and influencing tumorigenesis.However,the clinical implications of DNA polymerases in tumorigenesis and their potential as anti-cancer therapy targets are not well understood.Methods:We conducted a systematic analysis using TCGA Pan-Cancer Atlas data and Gene Set Cancer Analysis results to examine the expression profiles of 15 DNA polymerases(POLYs)and their clinical correlations.We also evaluated the prognostic value of POLYs by analyzing their expression levels in relation to overall survival time(OS)using Kaplan-Meier survival curves.Additionally,we investigated the correlations between POLY expression and immune cells,DNA damage repair(DDR)pathways,and ubiquitination.Drug sensitivity analysis was performed to assess the relationship between POLY expression and drug response.Results:Our analysis revealed that 14 out of 15 POLYs exhibited significantly distinct expression patterns between tumor and normal samples across most cancer types,except for DNA nucleotidylexotransferase(DNTT).Specifically,POLD1 and POLE showed elevated expression in almost all cancers,while POLQ exhibited high expression levels in all cancer types.Some POLYs showed heightened expression in specific cancer subtypes,while others exhibited low expression.Kaplan-Meier survival curves demonstrated significant prognostic value of POLYs in multiple cancers,including PAAD,KIRC,and ACC.Cox analysis further validated these findings.Alteration patterns of POLYs varied significantly among different cancer types and were associated with poorer survival outcomes.Significant correlations were observed between the expression of POLY members and immune cells,DDR pathways,and ubiquitination.Drug sensitivity analysis indicated an inverse relationship between POLY expression and drug response.Conclusion:Our comprehensive study highlights the significant role of POLYs in cancer development and identifies them as promising prognostic and immunological biomarkers for various cancer types.Additionally,targeting POLYs therapeutically holds promise for tumor immunotherapy.

The ubiquitin system： a critical regulator of innate immunity and pathogen-host interactions

The ubiquitin system comprises enzymes that are responsible for ubiquitination and deubiquitination, as well as ubiquitin receptors that are capable of recognizing and deciphering the ubiquitin code, which act in coordination to regulate almost all host cellular processes, including host-pathogen interactions. In response to pathogen infection, the host innate immune system launches an array of distinct antimicrobial activities encompassing inflammatory signaling, phagosomal maturation, autophagy and apoptosis, all of which are fine-tuned by the ubiquitin system to eradicate the invading pathogens and to reduce concomitant host damage. By contrast, pathogens have evolved a cohort of exquisite strategies to evade host innate immunity by usurping the ubiquitin system for their own benefits. Here, we present recent advances regarding the ubiquitin system-mediated modulation of host-pathogen interplay, with a specific focus on host innate immune defenses and bacterial pathogen immune evasion.

Ubiquitin-proteasome system and oxidative stress in liver transplantation

A major issue in organ transplantation is the development of a protocol that can preserve organs under optimal conditions. Damage to organs is commonly a consequence of flow deprivation and oxygen starvation following the restoration of blood flow and reoxygenation. This is known as ischemia-reperfusion injury(IRI): a complex multifactorial process that causes cell damage. While the oxygen deprivation due to ischemia depletes cell energy, subsequent tissue oxygenation due to reperfusion induces many cascades, from reactive oxygen species production to apoptosis initiation. Autophagy has also been identified in the pathogenesis of IRI, although such alterations and their subsequent functional significance are controversial. Moreover, proteasome activation may be a relevant pathophysiological mechanism. Different strategies have been adopted to limit IRI damage, including the supplementation of commercial preservation media with pharmacological agents or additives. In this review, we focus on novel strategies related to the ubiquitin proteasome system and oxidative stress inhibition, which have been used to minimize damage in liver transplantation.

Peroxisome proliferator activated receptor-γ and the ubiquitin-proteasome system in colorectal cancer

Peroxisome proliferator activated receptor-γ (PPARγ), a transcription factor of the nuclear receptor superfamily plays a significant role in colorectal cancer pathogenesis. In most experimental systems PPARγ activation has tumor suppressing effects in the colon. PPARγ is regulated at multiple levels by the ubiquitin-proteasome system (UPS). At a first level, UPS regulates PPARγ transcription. This regulation involves both PPARγ transcription specific factors and the general transcription machinery. At a second level UPS regulates PPARγ and its co-factors themselves, as PPARγ and many co-factors are proteasome substrates. At a third level of regulation, transduction pathways working in parallel but also having interrelations with PPARγ are regulated by the UPS, creating a network of regulation in the colorectal carcinogenesisrelated pathways that are under UPS control. Activation of PPARγ transcription by direct pharmacologic activators and by stabilization of its molecule by proteasome inhibitors could be strategies to be exploited in colorectal cancer treatment.

Ubiquitin proteasome system research in gastrointestinal cancer

The ubiquitin proteasome system(UPS) is important for the degradation of proteins in eukaryotic cells. It is involved in nearly every cellular process and plays an important role in maintaining body homeostasis. An increasing body of evidence has linked alterations in the UPS to gastrointestinal malignancies,including esophageal,gastric and colorectal cancers. Here,we summarize the current literature detailing the involvement of the UPS in gastrointestinal cancer,highlighting its role in tumor occurrence and development,providing information for therapeutic targets research and antigastrointestinal tumor drug design.

DI-3-n-butylphthalide exerts neuroprotective effects by modulating hypoxia-inducible factor 1-alpha ubiquitination to attenuate oxidative stress-induced apoptosis

DI-3-n-butylphthalide is used to treat mild and moderate acute ischemic stroke.However,the precise underlying mechanism requires further investigation.In this study,we investigated the molecular mechanism of DI-3-n-butylphthalide action by various means.We used hydrogen peroxide to induce injury to PC12cells and RAW264.7 cells to mimic neuronal oxidative stress injury in stroke in vitro and examined the effects of DI-3-n-butylphthalide.We found that DI-3-nbutylphthalide pretreatment markedly inhibited the reduction in viability and reactive oxygen species production in PC12 cells caused by hydrogen peroxide and inhibited cell apoptosis.Furthermore,DI-3-n-butylphthalide pretreatment inhibited the expression of the pro-apoptotic genes Bax and Bnip3.DI-3-nbutylphthalide also promoted ubiquitination and degradation of hypoxia inducible factor 1α,the key transcription factor that regulates Bax and Bnip3 genes.These findings suggest that DI-3-n-butylphthalide exhibits a neuroprotective effect on stroke by promoting hypoxia inducible factor-1α ubiquitination and degradation and inhibiting cell apoptosis.

Neuroendocrine differentiation and the ubiquitinproteasome system in cancer:Partners or enemies?

Neuroendocrine(NE)differentiation of cancer and deregulation of the ubiquitin-proteasome system(UPS)are two processes that have been independently linked to the development of aggressive and treatment-resistant tumors.Striking data suggest a plausible interconnection between these two mechanisms,based on indirect evidence of neuropeptide-induced effects on UPS,reversed by proteasome inhibition and deubiquitinaselike properties of NE markers.Deciphering the model of their exact interactions is one of the keys to targeting the NE malignant phenotype more effectively.

Research Progress in Function and Regulation of E3 Ubiquitin Ligase SMURF1

Smad ubiquitylation regulatory factor 1(Smurf1)is an important homologous member of E6-AP C-terminus type E3 ubiquitin ligase.Initially,Smurf1 was reportedly involved in the negative regulation of the bone morphogenesis protein(BMP)pathway.After further research,several studies have confirmed that Smurf1 is widely involved in various biological processes,such as bone homeostasis regulation,cell migration,apoptosis,and planar cell polarity.At the same time,recent studies have provided a deeper understanding of the regulatory mechanisms of Smurf1’s expression,activity,and substrate selectivity.In our review,a brief summary of recent important biological functions and regulatory mechanisms of E3 ubiquitin ligase Smurf1 is proposed.

Calcyclin-binding protein contributes to cholangiocarcinoma progression by inhibiting ubiquitination of MCM2

Background:Cholangiocarcinoma(CCA)represents the epithelial cell cancer with high aggressiveness whose five-year survival rate is poor with standard treatment.Calcyclin-binding protein(CACYBP)shows aberrant expression within several malignant tumors,but the role of CACYBP in CCA remains unknown.Methods:Immunohistochemical(IHC)analysis was used to identify CACYBP overexpression in clinical samples of CCA patients.Moreover,its correlation with clinical outcome was revealed.Furthermore,CACYBP’s effect on CCA cell growth and invasion was investigated in vitro and in vivo using loss-of-function experiments.Results:CACYBP showed up-regulation in CCA,which predicts the dismal prognostic outcome.CACYBP had an important effect on in-vitro and in-vivo cancer cell proliferation and migration.Additionally,knockdown of CACYBP weakened protein stability by promoting ubiquitination of MCM2.Accordingly,MCM2 up-regulation partly reversed CACYBP deficiency’s inhibition against cancer cell viability and invasion.Thus,MCM2 might drive CCA development by Wnt/β-catenin pathway.Conclusions:CACYBP exerted a tumor-promoting role in CCA by suppressing ubiquitination of MCM2 and activating Wnt/β-catenin pathway,hence revealing that it may be the possible therapeutic target for CCA treatment.

High Level of Ubiquitin Conjugate Enzyme E2O Indicates Poor Prognosis of Patients with Hepatocellular Carcinoma

Objective Ubiquitin conjugate enzyme E2O(UBE2O)is a ubiquitin-conjugating enzyme that has been reported to be involved in tumorigenesis.This study investigated the role of UBE2O in hepatocellular carcinoma(HCC).Methods The expression of UBE2O was detected using qRT-PCR,Western blotting,and immunohistochemical staining.Cell proliferation and Transwell assays were used to detect proliferation,migration,and invasion of HCC cells,respectively.Bioinformatic analysis was performed to analyze the relationship between UBE2O and the clinical features,prognosis,and immune cell infiltration of HCC.Results UBE2O was significantly over-expressed in HCC tissues.High expression of UBE2O was associated with poor tumor grade and poor prognosis.Functional experiments showed that down-regulation of UBE2O inhibited HCC cell proliferation,migration,and invasion.Co-expression gene analysis and gene set enrichment analysis showed that UBE2O was associated with protein hydrolysis,cell cycle,and cancer-related pathways in HCC.The results of immune analysis revealed that the expression of UBE2O was positively correlated with the immune infiltration and expression of immune-related chemokines of HCC.Conclusions UBE2O is significantly correlated with the prognosis of HCC and may be a valuable prognostic biomarker for HCC.

UCHL5 inhibits U251 glioma cell proliferation and tumor growth via stabilizing and deubiquitinating PTEN

Glioma is the most common primary brain tumor.Exploration of new tumorigenesis mechanism of glioma is critical to determine more effective treatment targets as well as to develop effective prognosis methods that can enhance the treatment efficacy.We previously demonstrated that the deubiquitinase biquitin carboxyl-terminal hydrolase L5(UCHL5)was downregulated in human glioma.However,the effect and mechanism of UCHL5 on the proliferation of glioma cells remains unknown.Methods:Transfection of siRNA was used to knockdown the expression of UCHL5 in U251 cells.The 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide(MTT)assay,Edu assay,and colony formation assay were employed to identify the effect of UCHL5 on the proliferation of U251 glioma cells.Western blotting and quantitative real-time PCR were carried out to detect the interaction of UCHL5 and PTEN.The effect of UCHL5 on the growth of glioma in vivo was evaluated in nude mice.Then Immunohistochemistry(IHC)were performed to analysis the expression of UCHL5 and PTEN in human glioma tissues.Results:Here,we have reported that silencing of UCHL5 could promote the proliferation of U251 glioma cells through MTT assay,Edu assay,and colony formation assay.Mechanically,we revealed that UCHL5 stabilizes the phosphatase and tensin homolog(PTEN)expression by deubiquitination,thereby inhibiting cell proliferation in U251 cells.Tumor xenograft experiments further demonstrated that silencing the UCHL5 expression could accelerate U251 cell growth in vivo.Finally,in human glioma tissue microarray,the positive correlation between UCHL5 and PTEN expression was confirmed through IHC assay.Conclusion:UCHL5 restrains the proliferation of U251 glioma cells by stabilizing and deubiquitinating PTEN.Our findings provide ideas for developing enhanced targeted PTEN therapy for patients with glioma.

Isolation and characterization ofβ-transducin repeat-containing protein ligands screened using a high-throughput screening system

β-transducin repeat-containing protein(β-TrCP)is an F-box protein subunit of the E3 Skp1-Cullin-F box(SCF)type ubiquitin-ligase complex,and provides the substrate specificity for the ligase.To find potent ligands ofβ-TrCP useful for the proteolysis targeting chimera(PROTAC)system usingβ-TrCP in the future,we developed a high-throughput screening system for small moleculeβ-TrCP ligands.We screened the chemical library utilizing the system and obtained several hit compounds.The effects of the hit compounds on in vitro ubiquitination activity of SCFβ-TrCP1 and on downstream signaling pathways were examined.Hit compounds NPD5943,NPL62020-01,and NPL42040-01 inhibited the TNFα-induced degradation of IκBαand its phosphorylated form.Hence,they inhibited the activation of the transcription activity of NF-κB,indicating the effective inhibition ofβ-TrCP by the hit compounds in cells.Next,we performed an in silico analysis of the hit compounds to determine the important moieties of the hit compounds.Carboxyl groups of NPL62020-01 and NPL42040-01 and hydroxyl groups of NPD5943 created hydrogen bonds withβ-TrCP similar to those created by intrinsic target phosphopeptides ofβ-TrCP.Our findings enhance our knowledge of useful small molecule ligands ofβ-TrCP and the importance of residues that can be ligands ofβ-TrCP.

Changes and significance of serum ubiquitin carboxyl-terminal hydrolase L1 and glial fibrillary acidic protein in patients with glioma

BACKGROUND Brain gliomas are malignant tumors with high postoperative recurrence rates.Early prediction of prognosis using specific indicators is of great significance.AIM To assess changes in ubiquitin carboxy-terminal hydrolase L1(UCH-L1)and glial fibrillary acidic protein(GFAP)levels in patients with glioma pre-and postoperatively.METHODS Between June 2018 and June 2021,91 patients with gliomas who underwent surgery at our hospital were enrolled in the glioma group.Sixty healthy volunteers were included in the control group.Serum UCH-L1 and GFAP levels were measured in peripheral blood collected from patients with glioma before and 3 d after surgery.UCH-L1 and GFAP levels in patients with glioma with different clinicopathological characteristics were compared before and after surgery.The patients were followed-up until February 2022.Postoperative glioma recurrence was recorded to determine the serum UCH-L1 and GFAP levels,which could assist in predicting postoperative glioma recurrence.RESULTS UCH-L1 and GFAP levels in patients with glioma decreased significantly 3 d after surgery compared to those before therapy(P<0.05).However,UCH-L1 and GFAP levels in the glioma group were significantly higher than those in the control group before and after surgery(P<0.05).There were no statistically significant differences in preoperative serum UCH-L1 and GFAP levels among patients with glioma according to sex,age,pathological type,tumor location,or number of lesions(P>0.05).Serum UCH-L1 and GFAP levels were significantly lower in the patients with WHO grade I-II tumors than in those with gradeⅢ-IV tumors(P<0.05).Serum UCH-L1 and GFAP levels were lower in the patients with tumor diameter≤5 cm than in those with diameter>5 cm,in which the differences were statistically significant(P<0.05).Glioma recurred in 22 patients.The preoperative and 3-d postoperative serum UCH-L1 and GFAP levels were significantly higher in the recurrence group than these in the non-recurrence group(P<0.05).Receiver operating characteristic curves were plotted.The areas under the curves of preoperative serum UCH-L1 and GFAP levels for predicting postoperative glioma recurrence were 0.785 and 0.775,respectively.However,the efficacy of serum UCH-L1 and GFAP levels 3 d after surgery in predicting postoperative glioma recurrence was slightly lower compared with their preoperative levels.CONCLUSION UCH-L1 and GFAP efficiently reflected the development and recurrence of gliomas and could be used as potential indicators for the recurrence and prognosis of glioma.

The effect of estrogen-mediated ubiquitin on cardiovascular diseases:a bioinformatics analysis

Objective:Using data mining tools,study the potential pathways of estrogen’s cardiovascular effects.Methods:The GeneExpression Omnibus database was used to download the relevant high-throughput microarray dataset GSE72180,which was then analyzed for differential genes using the GEO2R online analysis tool,gene function and pathway enrichment analysis using DAVID 6.8,protein interaction network analysis using the STRING database,and core network extraction using the MCODE algorithm.Results:A total of 131 differential genes were identified and enriched for gene function and signaling pathway analysis,which indicated that these genes were related with focal adhesion and the HIF-1 signaling pathway.MCODE algorithm analysis extracted 1 core sub-network of these genes to be related to ubiquitin protein transferase activity,protein polyubiquitination,protein ubiquitination involved in ubiquitin-dependent proteolytic metabolic processes,ligase activity,and clustering on ubiquitin-mediated protein hydrolysis signaling pathway.Conclusion:By using data mining tools,it is possible to identify how estrogen may influence the cardiovascular system by controlling the ubiquitination process.This information may be used as a reference for etiology and preventive studies of cardiovascular illnesses.

泛素-蛋白酶体系统在寄生原虫生长发育中的调控作用及潜在药物靶点分析

蛋白质降解是细胞维持正常生命活动的重要途径之一,其中泛素-蛋白酶体系统发挥关键作用。泛素-蛋白酶体系统参与调控细胞分化、细胞凋亡、DNA复制、蛋白质质量控制等生命活动。研究表明,对该系统中的功能蛋白进行干预,可直接影响寄生原虫的生长发育。本文主要探讨近年关于泛素-蛋白酶体系统在寄生原虫生长分化过程中发挥的关键作用,揭示其作用靶点,为开发新型抗原虫药物提供思路。

玉米Ubiquitin启动子的克隆及功能鉴定

根据Cornejo发表的Ubiquitin启动子的序列,设计引物从玉米自交系18红中克隆出该启动子,测序证明与发表的序列具有98%的同源性,并构建了带有该启动子和GUS基因的植物表达载体,将重组质粒导入农杆菌LBA4404,用农杆菌介导法转入烟草和小麦愈伤中,通过GUS染色反应,证明克隆的启动子在单子叶和双子叶植物中均有活性。

泛素-蛋白酶体系统与神经系统疾病的研究进展

泛素-蛋白酶体系统(UPS)是一种内部蛋白质分解机制,是细胞一系列生命过程的重要调节器,可处理大部分细胞的蛋白质周转,可去除老化、损坏和错误折叠的蛋白质,与各种疾病的发生发展密切相关。近年来各个领域对该系统的研究已渐渐成为热点,多项研究表明UPS的异常变化与炎症、糖尿病、肝肾疾病、肿瘤等疾病的发生有关,与神经系统疾病也有着密不可分的联系。本文就泛素-蛋白酶体系统的组成及其在神经系统疾病中的作用和治疗进展进行综述。

Ubiquitin B在宫颈癌细胞凋亡中的作用及机制的初步探讨

目的:研究Ubiquitin B的过度表达对宫颈癌细胞凋亡的影响,并初步探讨其机制。方法:脂质体转染Ubiquitin B至宫颈癌细胞系HeLa细胞后,real-time PCR检测细胞内Ubiquitin B mRNA的表达水平;流式细胞术和DNA Ladder法检测其凋亡;PI法检测细胞周期变化;Western blot法检测凋亡相关蛋白Smad4和Mcl-1的表达。结果:转染Ubiquitin B后,HeLa细胞中Ubiquitin B mRNA的表达水平在转染24h后明显高于它在对照组细胞中的表达。与对照组相比,转染了Ubiquitin B的HeLa细胞凋亡显著增加。但Ubiquitin B的过表达对HeLa细胞的周期无明显影响。Western blot分析表明,凋亡相关蛋白Smad4在转染Ubiquitin B48h时表达增强,而Mcl-1表达明显减弱。结论:UbiquitinB可促进宫颈癌细胞系HeLa细胞凋亡,其机制可能是Ubiquitin B通过增强表达凋亡促进蛋白Smad4和降解凋亡抑制蛋白Mcl-1而促进了HeLa细胞的凋亡。