Small molecule deoxynyboquinone triggers alkylation and ubiquitination of Keap1 at Cys489 on Kelch domain for Nrf2 activation and inflammatory therapy

Activation of nuclear factor erythroid 2-related factor 2(Nrf2)by Kelch-like ECH-associated protein 1(Keap1)alkylation plays a central role in anti-inflammatory therapy.However,activators of Nrf2 through alkylation of Keap1-Kelch domain have not been identified.Deoxynyboquinone(DNQ)is a natural small molecule discovered from marine actinomycetes.The current study was designed to investigate the anti-inflammatory effects and molecular mechanisms of DNQ via alkylation of Keap1.DNQ exhibited significant anti-inflammatory properties both in vitro and in vivo.The pharmacophore responsible for the anti-inflammatory properties of DNQ was determined to be theα,β-unsaturated amides moieties by a chemical reaction between DNQ and N-acetylcysteine.DNQ exerted anti-inflammatory effects through activation of Nrf2/ARE pathway.Keap1 was demonstrated to be the direct target of DNQ and bound with DNQ through conjugate addition reaction involving alkylation.The specific alkylation site of DNQ on Keap1 for Nrf2 activation was elucidated with a synthesized probe in conjunction with liquid chromatography-tandem mass spectrometry.DNQ triggered the ubiquitination and subsequent degradation of Keap1 by alkylation of the cysteine residue 489(Cys489)on Keap1-Kelch domain,ultimately enabling the activation of Nrf2.Our findings revealed that DNQ exhibited potent anti-inflammatory capacity throughα,β-unsaturated amides moieties active group which specifically activated Nrf2 signal pathway via alkylation/ubiquitination of Keap1-Kelch domain,suggesting the potential values of targeting Cys489 on Keap1-Kelch domain by DNQ-like small molecules in inflammatory therapies.

Pathophysiological changes of muscle after ischemic stroke:a secondary consequence of stroke injury

Sufficient clinical evidence suggests that the damage caused by ischemic stroke to the body occurs not only in the acute phase but also during the recovery period,and that the latter has a greater impact on the long-term prognosis of the patient.However,current stroke studies have typically focused only on lesions in the central nervous system,ignoring secondary damage caused by this disease.Such a phenomenon arises from the slow progress of pathophysiological studies examining the central nervous system.Further,the appropriate therapeutic time window and benefits of thrombolytic therapy are still controversial,leading scholars to explore more pragmatic intervention strategies.As treatment measures targeting limb symptoms can greatly improve a patient’s quality of life,they have become a critical intervention strategy.As the most vital component of the limbs,skeletal muscles have become potential points of concern.Despite this,to the best of our knowledge,there are no comprehensive reviews of pathophysiological changes and potential treatments for post-stroke skeletal muscle.The current review seeks to fill a gap in the current understanding of the pathological processes and mechanisms of muscle wasting atrophy,inflammation,neuroregeneration,mitochondrial changes,and nutritional dysregulation in stroke survivors.In addition,the challenges,as well as the optional solutions for individualized rehabilitation programs for stroke patients based on motor function are discussed.

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.

Ubiquitination in osteosarcoma:unveiling the impact on cell biology and therapeutic strategies

Ubiquitination,a multifaceted post-translational modification,regulates protein function,degradation,and gene expression.The pivotal role of ubiquitination in the pathogenesis and progression of cancer,including colorectal,breast,and liver cancer,is well-established.Osteosarcoma,an aggressive bone tumor predominantly affecting adolescents,also exhibits dysregulation of the ubiquitination system,encompassing both ubiquitination and deubiquitination processes.This dysregulation is now recognized as a key driver of osteosarcoma development,progression,and chemoresistance.This review highlights recent progress in elucidating how ubiquitination modulates tumor behavior across signaling pathways.We then focus on the mechanisms by which ubiquitination influences osteosarcoma cell function.Finally,we discuss the potential for targeting the ubiquitin-proteasome system in osteosarcoma therapy.By unraveling the impact of ubiquitination on osteosarcoma cell physiology,we aim to facilitate the development of novel strategies for prognosis,staging,treatment,and overcoming chemoresistance.

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.

Expression Pattern, Interaction Network, and Functional Analysis of the Arabidopsis Botrytis Susceptible1 Interactor

E3 ubiquitin ligases are participated in numerous processes, regulating the response to biotic and abiotic stresses. Botrytis susceptible1 interactor (BOI) is a RING (Really Interesting New Gene)-type E3 ligase that mediates the ubiquitination of BOS1 (Botrytis susceptible1), a transcription factor involved in stress and pathogen responses. Although BOI is an E3 ligase, there are reports to show that BOI interacts with target proteins such as DELLAs or CONSTANS to repress gibberellin responses and flowering without the degradation of the target proteins. In this article, we utilize diversified methods to comprehensively analyze the expression pattern, interaction network and function of BOI gene. Firstly, 1800 bp upstream region of BOI gene from Arabidopsis thaliana (Arabidopsis) genome was isolated, and fused GUS reporter gene. The resulting expression cassette was introduced into wild-type Arabidopsis through Agrobacterium-mediated transformation. The result demonstrated that BOI gene was expressed predominantly in leaves, siliques, young roots, and flowering tissues, indicating that BOI gene may be involved in multiple processes in plant growth and development in Arabidopsis. Besides, eight candidate interacting proteins were obtained from the Arabidopsis cDNA library via yeast two-hybrid technology, including EXO70E2 (AT5G61010), WRKY7 (AT4G24240), WRKY11 (AT4G31550), WRKY17 (AT2G24570), UBP20 (AT4G17895), L5 (AT1G12290), SAUR9 (AT4G36110) and TCP21 (AT5G08330). Functional analysis of these candidate interacting proteins manifested that they related to multiple pathways, including biological and abiotic stress, programmed cell death, protein degradation, material metabolism and transcriptional regulation. In addition, the results of the transient assay proclaimed that BOI protein affects the protein stability of EXO70E2 and L5 through its E3 ubiquitin ligase activity. Our results provide novel clues for a better understanding of molecular mechanisms underlying BOI-mediated regulations.

反复离心运动对大鼠骨骼肌损伤和蛋白质降解机制的影响

目的:探讨连续离心运动训练对骨骼肌中Calpain和Ubiquitin含量的影响及其与骨骼肌损伤之间的关系;方法:雄性SD大鼠29只随机分为对照组、离心训练后即刻组、24h组和7天组。训练组大鼠连续进行7天的下坡跑运动,分别在末次训练后即刻,24h和第7天取股四头肌,测定股四头肌的超微结构、血清LDH和CK活性以及骨骼肌中Calpain-1、Calpain-2和Ubiquitin含量;结果:1)7天离心训练后即刻和24h,股四头肌超微结构的损伤性变化呈渐进性加重,离心训练后24h组出现明显的肌丝坏死。训练后第7天仍不能完全恢复。血清CK和LDH活性的变化与大鼠股四头肌超微结构的变化相一致。2)与对照组相比,末次训练后即刻骨骼肌中Calpain-1、Calpain-2和Ubiquitin含量均显著升高;训练后24h,Calpain-1和Calpain-2含量进一步升高,其中,Calpain-1显著高于对照组和训练后24h组,Calpain-2虽显著高于对照组,但与训练后即刻组相比无显著性差异;而Ubiquitin含量显著低于训练后即刻组。训练后第7天,Calpain-1和Calpain-2含量显著低于训练后24h组,但仍然高于对照组;而Ubiquitin含量虽高于训练后24h组和对照组,但无显著性差异;结论:1)连续的离心运动可能对骨骼肌纤维的损伤产生一定的累加作用;2)短期连续的离心训练后,骨骼肌中Calpain和Ubiquitin的动态变化几乎与骨骼肌超微结构的动态变化相一致。离心运动训练导致骨骼肌中Calpain和Ubiquitin含量的增加,可能是导致骨骼肌累积性损伤的重要机制。

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。

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。

Fanconi Anemia and Ubiquitination

Fanconi anemia （FA） is a rare recessive hereditary disease characterized clinically by congenital defects, progressive bone-marrow failure, and cancer predisposition. Cells from FA patients exhibit hypersensitivity to DNA cross-linking agents, such as mitomycin C （MMC）. To date, at least 12 FA genes have been found deleted or mutated in FA cells, and 10 FA gene products form a core complex involved in FA/BRCA2 DNA repair pathway-FA pathway. The ubiquitin E3 ligase FANCL, an important factor of FA core complex, co-functions with a new ubiquitin conjugating enzyme UBE2T to catalyze the monoubiquitination of FANCD2. FANCD2-Ub binds BRCA2 to form a new complex located in chromatin foci and then take part in DNA repair process. The deubiquitylating enzyme USP1 removes the mono-ubiquitin from FANCD2-Ub following completion of the repair process, then restores the blocked cell cycle to normal order by shutting off the FA pathway. In a word, the FANCD2 activity adjusted exquisitely by ubiquitination and/or deubiquitination in vivo may co-regulate the FA pathway involving in variant DNA repair pathway.

急性离心运动后骨骼肌超微结构、钙依赖性蛋白酶和泛素的动态变化

目的:探讨1次离心运动后大鼠骨骼肌超微结构、Calpains和Ubiquitin的动态变化。方法:30只雄性SD大鼠随机分为对照组和1次离心运动后即刻组、24 h组和7天组。各运动组大鼠进行1次下坡跑运动,速度16 m/min,坡度?16°,运动100 min后休息10 min,再运动100 min,总时间200 min。分别在急性运动后即刻、24 h和第7天取材,测定血清LDH、CK活性和股四头肌超微结构及Calpain-1、Calpain-2和Ubiquitin含量。结果:①1次离心运动后即刻组大鼠股四头肌肌丝排列混杂、卷曲;运动后24 h出现轻度溶解、断裂,Z线不规则,局部Z线消失;运动后7天超微结构与对照组相比无显著变化。血清CK和LDH活性变化与股四头肌超微结构变化一致。②与对照组相比,运动后即刻组大鼠股四头肌Calpain-1、Calpain-2和Ubiquitin含量均有所降低,但均无显著性差异;运动后24 h组股四头肌Calpain-1、Calpain-2和Ubiquitin含量均显著高于对照组和运动后即刻组;运动后7天组与运动后24 h组相比均显著下降,而与对照组相比均无显著性差异。结论:①1次离心运动所致的骨骼肌损伤有一定的延迟性,骨骼肌损伤在运动后即刻从整体看并不严重,但在运动后24 h出现明显损伤,运动后7天基本恢复。②急性离心运动后骨骼肌Calpain和Ubiquitin含量变化与骨骼肌损伤的动态变化基本一致。

CbDREB1A基因表达载体构建及转化水稻光温敏核不育系的研究

为了增强荠菜DREB1A基因在转基因水稻中的表达,构建了由Ubi启动子驱动的植物表达载体pUΩCbDREB3300。通过基因枪转化法将CbDREB1A基因导入水稻光温敏核不育系4008S,获得5个抗干旱胁迫的再生植株。运用PCR及Southern杂交技术对抗性再生植株进行鉴定,结果显示CbDREB1A基因已整合到水稻基因组中。干旱胁迫后转基因水稻植株脯氨酸含量显著高于对照,显示耐旱性增强。

Ubiquitin基因介导下的PRRSV GP5基因免疫特性研究

目的:探讨泛素基因对GP5基因免疫的影响。泛素-蛋白酶体途径是一种高效蛋白降解途径,主要负责真核细胞内蛋白选择性降解。方法:本研究将ORF5 DNA片段克隆到含泛素(Ub)基因的表达载体pCMV-Ub和pCMV载体,构建成重组质粒pCMV-Ub-GP5和pCMV-GP5。两种质粒DNA肌肉注射免疫BALb/c小鼠后,分别检测体液免疫反应和细胞免疫反应,比较GP5单基因和Ub-GP5融合基因DNA免疫所诱生免疫应答的强度。结果:二者均可诱生PRRSV ELJSA抗体和中和抗体,其抗体水平无明显差别,但Ub-GP5融合基因诱生的淋巴细胞反应和CTL反应明显高于GP5基因。结论:泛素基因可以促进GP5诱生细胞免疫反应。

选择性自噬的研究

自噬（autophagy）是广泛存在于真核细胞内的一种溶酶体降解途径。这个古老而保守的降解途径主要有三种形式：巨自噬（giant autophagy）、微自噬（microautophagy）和分子伴侣介导的自噬（chaperon－mediated autophagy，CMA）。自噬一直被认为是一个饥饿诱导的非选择性本体降解途径，通过细胞质成分的“自我消化”，细胞在有限的能源中回收所有的营养成分。泛素化底物通过泛素受体传递，后者包括 p62／SQSTM1（sequestosome1）、BRCA1基因1邻位（neighbor of BRCA1 gene 1，NRB1）、核点蛋白质52（nuclear protein 52，NDP52）、组蛋白去乙酰酶6（histone deacetylase 6，HDAC6）及自噬相关 FYVE 蛋白（autophagy－linked FYVE protein，ALFY），泛素依赖的传感器系统负责底物特异性。自噬清除之前，这些受体将泛素化底物连接到初期自噬体，后者携带有泛素样（ubiquitin－like，UbL）蛋白，如其表面的微管相关蛋白1轻链3（microtubule associated protein 1 light chain 3，LC3）或 GABAA 受体相关蛋白（GABAA receptor associated protein，GABARAP）。因此，自噬受体结合到泛素和 LC3或 GABARAP 蛋白能够通过选择性自噬调控蛋白质降解。依据其底物名称来区别各种类型的选择性途径，如线粒体自噬（mitophagy）、过氧化物酶体自噬（pexophagy）、内质网自噬（ reticulophagy）、核糖体自噬（ ribophagy）和异源自噬（xenophagy）。

玉米转录因子基因ZmASR1的克隆及植物表达载体构建

为深入研究玉米转录因子基因ZmASR1的功能,提高玉米株系的产量和抗逆性,根据http://www.maizegdb.org/网站上公布的玉米自交系B73的ZmASR1序列和Cornejo发表的Ubiquitin启动子的序列,设计引物从玉米自交系B73的DNA序列中克隆了ZmASR1基因和Ubiquitin启动子,并对ZmASR1基因进行了生物信息学分析。序列分析结果表明,ZmASR1基因DNA全长为1 381 bp,包含1个长度为131 bp的内含子序列,存在1个完整的开放阅读框417bp,编码138个氨基酸。氨基酸序列分析表明其具有ASR家族典型的保守结构域ABA_WDS(abscisic acid/water deficit stress),氨基酸序列的N端有该家族成员所特有的依赖于Zn2+的DNA结合位点,而C端则有1个核定位信号,玉米的ZmASR1与单子叶植物的ZmASR1亲缘关系较近,而与双子叶植物的ZmASR1亲缘关系较远。并构建了同时带有该启动子和ZmASR1基因的植物表达载体。

Ubiquitin真核表达载体构建及在293T细胞中的表达

为构建泛素分子pcDNA3.1-Myc-ubiquitin真核表达载体,实现其在293T细胞中表达。采用人工合成ubiquitin基因序列并加入c-Myc标签序列及EcoRⅠ和BamHⅠ酶切位点的方法,克隆至pcDNA3.1真核表达载体中。重组表达质粒经PCR和测序鉴定正确后,脂质体法转染入293T细胞。Western blot和间接免疫荧光法分析重组质粒在细胞中的蛋白表达及定位情况。菌落PCR及测序等分析结果显示:成功构建了pcDNA3.1-Myc-ubiquitin真核表达载体。免疫荧光和Western-Blot结果显示:Myc-ubiquitin重组表达质粒在293T细胞中获得高效表达且蛋白定位于胞浆。由此可知,成功构建pcDNA3.1-Myc-ubiquitin融合表达载体并在293T细胞中高效表达,为课题组进一步探讨与泛素化修饰相关的neuritin的作用机制及功能奠定基础。

昆虫杆状病毒泛素基因研究进展

昆虫杆状病毒是目前已知唯一编码泛素 (ubiquitin)的病毒。迄今 ,已克隆了 8种该类病毒的泛素基因。与真核生物Uba5 2 (80 )相似 ,这些基因在一个泛素分子的C 末端都有不同长度的融合 ,其中斜纹夜蛾核多角体病毒 (Spodopteralituramulticapsidnucleopolyhedrovirus ,SpltMNPV)的ubiquitin gp37基因是一个典型的融合基因。近年来 ,对苜蓿银纹夜蛾核多角体病毒 (Autographacaliforniamulticapsidnucleopolyhedrovirus ,AcMNPV)

Tween-80在体内、外对温热抗肿瘤作用的影响

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