As the major pathway mediating specific protein degradation in eukaryotes, ubiquitin-proteasome system (UPS) is involved in various physiological and pathological processes such as cell cycle regulation, immune response, signal transduction and DNA-repair. Deubiquitinases (DUB) maintain the balance of UPS and related physiological processes via reversibly removing ubiquitin from the covalently modified protein substrates, which have been implicated in various disease processes in case of their imbalance expression. Because DUB plays critical regulating roles in the UPS pathway, they may be also the ideal drug targets for severe and intractable human diseases, such as cancer and neurodegenerative disease. With the rapid development of proteomic technology, systematical investigation of specific substrates and interacting proteins of varied DUB via mass spectrometry approach may shed light on these DUB's biological function and regulating roles in the physiological and pathogenic states. In this review, we briefly introduce the characteristics of DUB and summarize the recent application and progresses of proteomics in DUB research.
Humans ; Mass Spectrometry ; Proteasome Endopeptidase Complex ; metabolism ; Proteomics ; Signal Transduction ; Ubiquitin ; metabolism ; Ubiquitin-Specific Proteases ; metabolism

Apoptosis ; Autophagy ; Ferroptosis ; Iron/metabolism* ; Sequestosome-1 Protein/metabolism* ; Ubiquitin-Specific Proteases/metabolism*

OBJECTIVE: To study the expression and significance of ubiquitin-specific protease 7 (USP7) and the key factors of the Wnt signaling pathway in the lung tissue of preterm rats after hyperoxia exposure. METHODS: A total of 180 preterm neonatal Wistar rats were randomly divided into an air control group, an air intervention group, a hyperoxia control group, and a hyperoxia intervention group, with 45 rats in each group. Lung injury was induced by hyperoxia exposure in the hyperoxia groups. The preterm rats in the intervention groups were given intraperitoneal injection of the USP7 specific inhibitor P5091 (5 mg/kg) every day. The animals were sacrificed on days 3, 5, and 9 of the experiment to collect lung tissue specimens. Hematoxylin-eosin staining was used to observe the pathological changes of lung tissue. RT-PCR and Western blot were used to measure the mRNA and protein expression levels of USP7 and the key factors of the Wnt signaling pathway β-catenin and α-smooth muscle actin (α-SMA) in lung tissue. RESULTS: The air groups had normal morphology and structure of lung tissue; on days 3 and 5, the hyperoxia control group showed obvious alveolar compression and disordered structure, with obvious inflammatory cells, erythrocyte diapedesis, and interstitial edema. On day 9, the hyperoxia control group showed alveolar structural disorder and obvious thickening of the alveolar septa. Compared with the hyperoxia control group at the corresponding time points, the hyperoxia intervention group had significantly alleviated disordered structure, inflammatory cell infiltration, and bleeding in lung tissue. At each time point, the hyperoxia groups had a significantly lower radial alveolar count (RAC) than the corresponding air groups ( CONCLUSIONS Hyperoxia exposure can activate the Wnt/β-catenin signaling pathway, and USP7 may participate in hyperoxic lung injury through the Wnt/β-catenin signaling pathway. The USP7 specific inhibitor P5091 may accelerate the degradation of β-catenin by enhancing its ubiquitination, reduce lung epithelial-mesenchymal transition, and thus exert a certain protective effect against hyperoxic lung injury.
Animals ; Animals, Newborn ; Hyperoxia/physiopathology* ; Lung/physiopathology* ; Random Allocation ; Rats ; Rats, Wistar ; Thiophenes/pharmacology* ; Ubiquitin-Specific Peptidase 7/metabolism* ; Ubiquitin-Specific Proteases ; Wnt Signaling Pathway

Transforming growth factor-β (TGF-β) members are key cytokines that control embryogenesis and tissue homeostasis via transmembrane TGF-β type II (TβR II) and type I (TβRI) and serine/threonine kinases receptors. Aberrant activation of TGF-β signaling leads to diseases, including cancer. In advanced cancer, the TGF-β/SMAD pathway can act as an oncogenic factor driving tumor cell invasion and metastasis, and thus is considered to be a therapeutic target. The activity of TGF-β/SMAD pathway is known to be regulated by ubiquitination at multiple levels. As ubiquitination is reversible, emerging studies have uncovered key roles for ubiquitin-removals on TGF-β signaling components by deubiquitinating enzymes (DUBs). In this paper, we summarize the latest findings on the DUBs that control the activity of the TGF-β signaling pathway. The regulatory roles of these DUBs as a driving force for cancer progression as well as their underlying working mechanisms are also discussed.
Animals ; Humans ; Molecular Targeted Therapy ; Receptors, Transforming Growth Factor beta ; metabolism ; Signal Transduction ; Smad Proteins ; physiology ; Transforming Growth Factor beta ; physiology ; Ubiquitin Thiolesterase ; metabolism ; Ubiquitin-Specific Proteases ; Ubiquitination

AIMTo study the incidence of single nucleotide polymorphisms in ubiquitin-specific protease 26 (USP26) gene and its involvement in idiopathic male infertility in China.

METHODSRoutine semen analysis was performed. Infertility factors such as immunological, infectious and biochemical disorders were examined to select patients with idiopathic infertility. DNA was isolated from peripheral blood of the selected patients and control population, which were examined for mutations using polymerase chain reaction-single strand conformation polymorphism analysis. Furthermore, nucleotide sequences were sequenced in some patients and controls.

RESULTSOf 41 infertile men, 9 (22.0%, P = 0.01) had changes in USP26 gene on the X chromosome. A compound mutation (364insACA; 460G right triple arrow A) was detected in 8 patients (19.5%, P = 0.01) and a 1044T right triple arrow A substitution was found in 1 patient (2.4%, P > 0.05). All three variations led to changes in the coding amino acids. Two substitutions predict some changes: 460G right triple arrow A changes a valine into an isoleucine, and 1044T right triple arrow A substitutes a leucine for a phenylalanine. Another insertion of three nucleotides ACA causes an insertion of threonine. No other changes were found in the remaining patients and fertile controls.

CONCLUSIONThe USP26 gene might be of importance in male reproduction. Mutations in this gene might be associated with male infertility, and might negatively affect testicular function. Further research on this issue is in progress.

Asian Continental Ancestry Group ; ethnology ; genetics ; Case-Control Studies ; China ; Cysteine Endopeptidases ; genetics ; metabolism ; Endopeptidases ; genetics ; metabolism ; Humans ; Incidence ; Infertility, Male ; ethnology ; genetics ; Leydig Cells ; metabolism ; Male ; Polymorphism, Single Nucleotide ; genetics ; RNA, Messenger ; genetics ; metabolism ; Sertoli Cells ; metabolism ; Spermatogenesis ; genetics ; Testis ; metabolism ; Ubiquitin-Specific Proteases

The deubiquitinating enzyme ubiquitin specific peptidase 15 (USP15) is regarded as a regulator of TGFβ signaling pathway. This process depends on Smad7, the inhibitory factor of the TGFβ signal, and type I TGFβ receptor (TβR-I), one of the receptors of TGFβ. The expression level of USP15 seems to play vital roles in the pathogenesis of many neoplasms, but so far there has been no report about USP15 in psoriasis. In this study, immunohistochemical staining of USP15, TβR-I and Smad7 was performed in 30 paraffin-embedded psoriasis specimens and 10 normal specimens to investigate the expression of USP15, TβR-I and Smad7 in psoriasis and to explore the relevance among them. And USP15 small interfering RNA (USP15 siRNA) was used to transfect Hacat cells to detect the mRNA expression of TβR-I and Smad7. Of 30 cases of psoriasis in active stage, 28, 24 and 26 cases were positive for USP15, TβR-I and Smad7 staining, respectively. The positive rates of USP15 and Smad7 were significantly higher in psoriasis specimens than in normal skin specimens (44.1%±26.0% vs. 6.1%±6.6%, 47.2%±27.1% vs. 6.6%±7.1%), and positive rate of TβR-I (20.3%±22.2%) in psoriasis was lower than that in normal skin specimens (46.7%±18.2%). There was a significant positive correlation between USP15 and Smad7 expression, and significant negative correlations between USP15 and TβR-expression, an I d between TβR- and Smad7 expression I in psoriasis. After transfection of USP15 siRNA in Hacat cells, the expression of TβR-mRNA was up I -regulated and that of Smad7 was down-regulated. It is concluded that USP15 may play a role in the pathogenesis of psoriasis through regulating the TβR-I/Smad7 pathway and there may be other cell signaling pathways interacting with USP15 to take part in the development of psoriasis.
Adult ; Cell Line ; Female ; Gene Expression ; Humans ; Immunohistochemistry ; Keratinocytes ; cytology ; metabolism ; Male ; Middle Aged ; Protein-Serine-Threonine Kinases ; biosynthesis ; genetics ; Psoriasis ; genetics ; metabolism ; RNA Interference ; Receptors, Transforming Growth Factor beta ; biosynthesis ; genetics ; Reverse Transcriptase Polymerase Chain Reaction ; Signal Transduction ; genetics ; Skin ; metabolism ; Smad7 Protein ; biosynthesis ; genetics ; Ubiquitin-Specific Proteases ; biosynthesis ; genetics ; Young Adult

Gambogic acid (GA) is an anticancer agent in phase ‖b clinical trial in China but its mechanism of action has not been fully clarified. The present study was designed to search the possible target-related proteins of GA in cancer cells using proteomic method and establish possible network using bioinformatic analysis. Cytotoxicity and anti-migration effects of GA in MDA-MB-231 cells were checked using MTT assay, flow cytometry, wound migration assay, and chamber migration assay. Possible target-related proteins of GA at early (3 h) and late stage (24 h) of treatment were searched using a proteomic technology, two-dimensional electrophoresis (2-DE). The possible network of GA was established using bioinformatic analysis. The intracellular expression levels of vimentin, keratin 18, and calumenin were determined using Western blotting. GA inhibited cell proliferation and induced cell cycle arrest at G2/M phase and apoptosis in MDA-MB-231 cells. Additionally, GA exhibited anti-migration effects at non-toxic doses. In 2-DE analysis, totally 23 possible GA targeted proteins were found, including those with functions in cytoskeleton and transport, regulation of redox state, metabolism, ubiquitin-proteasome system, transcription and translation, protein transport and modification, and cytokine. Network analysis of these proteins suggested that cytoskeleton-related proteins might play important roles in the effects of GA. Results of Western blotting confirmed the cleavage of vimentin, increase in keratin 18, and decrease in calumenin levels in GA-treated cells. In summary, GA is a multi-target compound and its anti-cancer effects may be based on several target-related proteins such as cytoskeleton-related proteins.
Antineoplastic Agents ; pharmacokinetics ; Apoptosis ; drug effects ; Breast Neoplasms ; drug therapy ; metabolism ; Calcium-Binding Proteins ; genetics ; Cell Line, Tumor ; Cell Migration Assays ; Cell Migration Inhibition ; drug effects ; Cell Proliferation ; drug effects ; Computational Biology ; methods ; Cytoskeleton ; metabolism ; Electrophoresis, Gel, Two-Dimensional ; Flow Cytometry ; Gene Expression ; Humans ; Keratin-18 ; genetics ; Oxidation-Reduction ; Protein Biosynthesis ; drug effects ; Protein Transport ; Proteomics ; methods ; Transcription, Genetic ; drug effects ; Ubiquitin-Specific Proteases ; pharmacokinetics ; Vimentin ; genetics ; Xanthones ; pharmacokinetics