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.

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.

Chemical Synthesis of Structurally Defined Phosphorylated Ubiquitins Suggests Impaired Parkin Activation by Phosphorylated Ubiquitins with a Non-Phosphorylated Distal Unit

Mutations in genes encoding PINK1(PTEN-induced kinase 1)and Parkin(E3 ubiquitin ligase)are identified in familial Parkinson’s disease.However,it remains unclear whether the phosphorylated Ub chains activate wild-type Parkin(w-Parkin)or phosphorylated Parkin(p-Parkin),with the consequent expulsion of the damaged mitochondria.

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.

F-box only protein 2 exacerbates non-alcoholic fatty liver disease by targeting the hydroxyl CoA dehydrogenase alpha subunit

BACKGROUND Non-alcoholic fatty liver disease(NAFLD)is a major health burden with an increasing global incidence.Unfortunately,the unavailability of knowledge underlying NAFLD pathogenesis inhibits effective preventive and therapeutic measures.AIM To explore the molecular mechanism of NAFLD.METHODS Whole genome sequencing(WGS)analysis was performed on liver tissues from patients with NAFLD(n=6)and patients with normal metabolic conditions(n=6)to identify the target genes.A NAFLD C57BL6/J mouse model induced by 16 wk of high-fat diet feeding and a hepatocyte-specific F-box only protein 2(FBXO2)overexpression mouse model were used for in vivo studies.Plasmid transfection,co-immunoprecipitation-based mass spectrometry assays,and ubiquitination in HepG2 cells and HEK293T cells were used for in vitro studies.RESULTS A total of 30982 genes were detected in WGS analysis,with 649 up-regulated and 178 down-regulated.Expression of FBXO2,an E3 ligase,was upregulated in the liver tissues of patients with NAFLD.Hepatocyte-specific FBXO2 overexpression facilitated NAFLD-associated phenotypes in mice.Overexpression of FBXO2 aggravated odium oleate(OA)-induced lipid accumulation in HepG2 cells,resulting in an abnormal expression of genes related to lipid metabolism,such as fatty acid synthase,peroxisome proliferator-activated receptor alpha,and so on.In contrast,knocking down FBXO2 in HepG2 cells significantly alleviated the OA-induced lipid accumulation and aberrant expression of lipid metabolism genes.The hydroxyl CoA dehydrogenase alpha subunit(HADHA),a protein involved in oxidative stress,was a target of FBXO2-mediated ubiquitination.FBXO2 directly bound to HADHA and facilitated its proteasomal degradation in HepG2 and HEK293T cells.Supplementation with HADHA alleviated lipid accumulation caused by FBXO2 overexpression in HepG2 cells.CONCLUSION FBXO2 exacerbates lipid accumulation by targeting HADHA and is a potential therapeutic target for NAFLD。

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.

TRIM72‑mediated degradation of the short form of p62/SQSTM1 rheostatically controls selective autophagy in human cells

Dear Editor,Autophagy is an evolutionarily conserved catabolic process that involves the sequestration and transport of organelles,macromolecules,or invading microorganisms to lysosomes for degradation[1].Sequestosome 1(p62/SQSTM1)was the first protein shown to bind target-associated ubiquitin(Ub)and LC3 conjugated to the phagophore membrane,thus,acting as an important autophagy receptor for ubiquitinated targets[2].

Novel insights into the mechanism of reactive oxygen species-mediated neurodegeneration

Neurite degeneration,a major component of many neurodegenerative diseases,such as Parkinson’s disease,Alzheimer’s disease,and amyotrophic lateral sclerosis,is not part of the typical apoptosis signaling mechanism,but rather it appears that a self-destructive process is in action.Oxidative stress is a well-known inducer of neurodegenerative pathways:neuronal cell death and neurite degeneration.Although oxidative stress exerts cytotoxic effects leading to neuronal loss,the pathogenic mechanisms and precise signaling pathways by which oxidative stress causes neurite degeneration have remained entirely unknown.We previously reported that reactive oxygen species generated by NADPH oxidases induce activation of the E3 ubiquitin ligase ZNRF1 in neurons,which promotes neurite degeneration.In this process,the phosphorylation of an NADPH oxidase subunit p47-phox at the 345serine residue serves as an important checkpoint to initiate the ZNRF1-dependent neurite degeneration.Evidence provides new insights into the mechanism of reactive oxygen species-mediated neurodegeneration.In this review,we focus specifically on reactive oxygen species-induced neurite degeneration by highlighting a phosphorylation-dependent regulation of the molecular interaction between ZNRF1 and the NADPH oxidase complex.

Fine mapping of a major QTL qHYF_B06 for peanut yield

High yield is a major objective for peanut(Arachis hypogaea L.) breeding worldwide. However, fewer yield-related quantitative trait loci(QTL) have been reported in peanut than in other staple food crops such as rice(Oryza sativa), wheat(Triticum aestivum), and maize(Zea mays). This study aimed to identify stable major-effect QTL associated with pod yield per plant, hundred-pod weight for double-seeded pods,hundred-seed weight, shelling percentage, and pod number per plant, allowing us to predict candidate genes by means of transcriptome and genome sequencing. To this end, we used a population of recombinant inbred lines comprising 192 F9:11families derived from a JH6 × KX01-6 cross to construct a highresolution genetic map(1705.7 c M) consisting of 2273 polymorphic SNPs, with 0.75 c M(on average)between adjacent SNPs. We identified two high-confidence, yield-related QTL, qHYF_A08 and qHYF_B06, explaining 5.78%–31.40% of phenotypic variation and with LOD values of 5.10–24.48, in six environments. qHYF_A08 mainly explained the variation in shelling percentage, whereas qHYF_B06explained variation in hundred-pod weight and hundred-seed weight and accounted for 8.77%–31.40%of the variation in effective pod number per plant, pod number per plant, and shelling percentage. We narrowed down qHYF_B06 to an 890-kb interval using an advanced mapping population.Transcriptome and genome analyses revealed that only Arahy.129FS0 and Arahy.3R9A5K in the candidate mapping interval were differentially expressed between JH6 and KX01-6, with substantial structural variations in their promoter and coding regions. Genotypes of 208 peanut accessions determined using a diagnostic CAPS marker suggested that the two haplotypes of Arahy.3R9A5K were highly associated with hundred-seed weight and hundred-pod weight;this diagnostic CAPs marker could therefore be useful for selecting high-yielding lines during peanut breeding. Overall, our results provide valuable information for cloning alleles with favorable effects on peanut yield.

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 role of 5′-adenosine monophosphate-activated protein kinase(AMPK)in skeletal muscle atrophy

As a key coordinator of metabolism,AMP-activated protein kinase(AMPK)is vitally involved in skeletal muscle maintenance.AMPK exerts its cellular effects through its function as a serine/threonine protein kinase by regulating many downstream targets and plays important roles in the development and growth of skeletal muscle.AMPK is activated by phosphorylation and exerts its function as a kinase in many processes,including synthesis and degradation of proteins,mitochondrial biogenesis,glucose uptake,and fatty acid and cholesterol metabolism.Skeletal muscle atrophy is a result of various diseases or disorders and is characterized by a decrease in muscle mass.The pathogenesis and therapeutic strategies of skeletal muscle atrophy are still under investigation.In this review,we discuss the role of AMPK in skeletal muscle metabolism and atrophy.We also discuss targeting AMPK for skeletal muscle treatment,including exercise,AMPK activators including 5-amino-4-imidazolecarboxamide ribonucleoside and metformin,and low-level lasers.These studies show the important roles of AMPK in regulating muscle metabolism and function;thus,the treatment of skeletal muscle atrophy needs to take into account the roles of AMPK.

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.

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。