Effects of arsenic and its metabolites on p53 gene expression in BEAS-2B cells / 环境与职业医学

Background Arsenic is a human carcinogen. Arsenic and its metabolites affect the expression of p53, but whether there are any changes of p53 phosphorylation and ubiquitination levels in human bronchial epithelium cells (BEAS-2B) are not clear after exposure to arsenic and its metabolites. Objective To study the effects of arsenic and its metabolites monomethylarsic acid (MMA) and dimethylarsinic acid (DMA) on the expression of tumor suppressor gene p53 in BEAS-2B cells. Methods Different concentrations of sodium arsenite (NaAsO2) were used to infect BEAS-2B cells, and the cell viability was detected with CCK-8 reagent to determine the dose and time of NaAsO2 used for the following study. Based on the results of cell viability, the cells were divided into two panels: a sodium arsenide panel and an arsenic methylation metabolite penal. The doses of sodium arsenite were 0, 2, 4, and 6 μmol·L−1 NaAsO2; the arsenic methylation metabolite panel consisted of 0 μmol·L−1 NaAsO2 group (control), 6 μmol· L−1 MMA group, 6 μmol· L−1 DMA group， and 6 μmol· L−1 NaAsO2 group. The cells were collected after 48 h treatment, and the total protein and total RNA were extracted. The relative levels of p53 mRNA expression were determined by quantitative real-time polymerase chain reaction (qRT-PCR), the relative expression levels of p53 protein, p53 Ser9 and Ser15 phosphorylated proteins were determined by Western blot, and the level of p53 ubiquitination was detected by co-immunoprecipitation (CO-IP). Results Compared with the control group, the cell viability rates in all BEAS-2B cells treated by NaAsO2 were significantly reduced (P<0.05), and the 50% cell viability was observed at 6 μmol·L−1. Compared with the control group, the relative expression level of p53 mRNA gradually decreased after NaAsO2 (2, 4, 6 μmol·L−1) treatment (P<0.05), the relative expression levels of p53 protein and Ser9 phosphorylated protein induced by NaAsO2 also decreased gradually (P<0.05), and the relative expression level of p53 Ser15 phosphorylated protein induced by NaAsO2 followed the same pattern, but it was only lower than that of the control group in the 6 μmol·L−1 NaAsO2 group (P<0.05). Compared with the control group, there were no significant effects on the relative expression levels of p53 mRNA, p53 protein, Ser9 and Ser15 phosphorylated proteins in the MMA group and the DMA group. Compared with the control group, the expression level of p53 ubiquitination was significantly decreased and the expression of K48 ubiquitination decreased significantly after NaAsO2 infection. Conclusion Arsenic causes a decrease in the expression of the p53 protein in BEAS-2B cells, largely due to inhibition of the phosphorylated pathway and a decrease in mRNA expression, and protein changes caused by a decrease in p53 ubiquitination do not play a dominant role. MMA and DMA do not affect p53 gene expression.

Zoledronic acid affects osteogenic differentiation and bone formation by regulating the expression of SIRT3/P53 / 中华内分泌外科杂志

Objective:To explore the mechanism of zoledronic acid (ZOL) affects osteogenic differentiation and bone formation through the regulation of sirtuin 3 (SIRT3) / P53 expression.Methods:Bone marrow mesenchymal stem cells (BMSCs) were induced to differentiate into osteogenic cells, the expression of SIRT3 in the cells was detected, and the targeting regulation relationship between SIRT3 and P53 was analyzed. The intracellular expressions of SIRT3 and P53 were intervened and ZOL was used to treat the cells. MTT method, Western blot method and kit were used to detect cell viability, osteogenesis-related genes Osteoprotegerin (OPG), runt-related transcription factor 2 (Runx2) expression, alkaline phosphatase (ALP) activity and alizarin red S (ARS) staining, respectively. Ovariectomy (OVX) was used to construct a rat model and explore the effect of ZOL on the progression of osteoporosis (OP) in vivo.Results:ZOL promoted osteogenic differentiation of BMSCs. The expression of SIRT3 was down-regulated in the serum of OP patients (0.78±0.23) compared with that of healthy subjects (1.00±0.26 vs. 0.78±0.23. t=3.85, P<0.001). During the osteogenic differentiation of BMSCs, the expression level of SIRT3 gradually increased with the prolonged induction of osteogenesis. Compared with the p53 protein expression and BMSCs activity in the control group, SIRT3 knockout could increase the expression level of p53 protein (0.59±0.05 vs. 1.01±0.11. t=6.02, P=0.004) but inhibited the activity of BMSCs (100.00±8.41 vs. 51.26±5.59. t=8.36, P=0.001). After ZOL treatment, the inhibitory effect of SIRT3 on cell viability (49.61±5.11 vs. 87.61±7.31. t=7.38, P=0.002) and osteogenesis was relieved, and the level of P53 was inhibited (1.10±0.10 vs. 0.69±0.04. t=6.59, P=0.003). P53 overexpression partially offseted the effects of ZOL on cell viability (84.61±6.52 vs. 66.54±5.47. t=3.68, P=0.021) and osteogenesis. Compared with the sham surgery group, the OVX group showed inhibition of osteogenesis in rats, and ZOL treatment significantly improved osteogenic inhibition. ZOL treatment increased the expression level of SIRT3 protein in bone tissue of OVX rats, but inhibited the expression level of P53. Conclusion:ZOL promoted osteogenic differentiation and bone formation of BMSCs by promoting the ubiquitination and degradation of P53 by SIRT3.

Abnormal modification of alpha-synuclein and its mechanism in Parkinson's disease / 中国组织工程研究

BACKGROUND:The formation of Lewy bodies due to abnormal α-synuclein aggregation is a characteristic pathological change in Parkinson's disease.In recent years,several studies have revealed that the formation of α-synuclein aggregates is closely related to its post-translational modifications.The modification of α-synuclein such as phosphorylation,nitration,acetylation,and ubiquitination has attracted extensive attention in the pathogenesis and progression of Parkinson's disease. OBJECTIVE:To review the research progress in the effect of modification types and sites of α-synuclein on the characteristic pathological formation and progression of Parkinson's disease. METHODS:PubMed and CNKI databases were searched by the first author with the key words of"α-synuclein,Parkinson's disease,phosphorylation,acetylation,ubiquitination,nitration"in English and Chinese respectively to collect and sort out the literature related to abnormal modification of α-synuclein in recent years.Finally,61 articles were included for further review. RESULTS AND CONCLUSION:Abnormal modification of α-synuclein is closely related to its protein structure and its positive and negative charges.Its amino terminus is positively charged and prone to ubiquitination and acetylation modifications.The central hydrophobic region is prone to forming β-pleated sheet due to its hydrophobic property.The carboxyl terminus is negatively charged,which is the main phosphorylation modification region.Phosphorylation modification sites promote phosphorylation modification and are closely related to α-synuclein aggregation,while protein kinases can target the activation of translational modifications,which may help to promote or inhibit aggregate formation.The degradation pathway of α-synuclein mainly plays a role in removing pathological proteins.Various kinase catalysts contribute to impaired protein ubiquitination modifications that lead to abnormal protein accumulation,thereby exacerbating neurodegeneration.The amino-terminal acetylation of α-synuclein improves the shuttle ability of the protein to the cell membrane and slows down the protein aggregation,which may be the protection target of nerve cells.However,the acetylation modification of the mutant protein produces the opposite effect.The protein nitration modification is mainly related to oxidative stress.The aggregation tendency of the protein modified by nitration is enhanced under the action of reactive oxygen species.Different post-translational modifications have different effects.Therefore,elucidating the main mechanisms of their post-translational modifications and inhibiting the post-translational modifications that contribute to protein aggregation may provide a reference for new targets for early diagnosis and treatment of Parkinson's disease.

The Role of Ubiquitination in Regulating Ferroptosis / 生物化学与生物物理进展

Ferroptosis is a novel type of iron-dependent cell death driven by lipid peroxidation. More and more evidence shows that ferroptosis is related to various pathological conditions, such as neurodegenerative diseases, diabetic nephropathy, and cancer. Ferroptosis driven by lipid peroxidation may promote or inhibit the occurrence and development of these diseases. The intracellular antioxidant system plays an important role in resisting ferroptosis by inhibiting lipid peroxidation. The key pathways of ferroptosis include the amino acid metabolism pathway with SLC7A11-GPX4 as the key molecule, the iron metabolism pathway with ferritin or transferrin as the main component, and the lipid metabolism pathway. The occurrence of ferroptosis is regulated by intracellular proteins, which undergo various post-translational modifications, including ubiquitination. The ubiquitin-proteasome system (UPS) is one of the main degradation systems in cells. It catalyzes the ubiquitin molecule to label the protein and then the proteasome recognizes and degrades the target protein. UPS promotes ferroptosis by promoting the degradation of key ferroptosis molecules (such as SLC7A11, GPX4, and GSH) and antioxidant systems (such as NRF2). UPS can also inhibit ferroptosis by promoting the degradation of related molecules in the lipid metabolism pathway (such as ACLS4 and ALOX15). In this review, we summarize the latest research progress of ubiquitination modification in the regulation of ferroptosis, generalize the published studies on the regulation of ferroptosis by E3 ubiquitin ligase and deubiquitination, and sum up the targets of ubiquitin ligase and deubiquitination regulating ferroptosis, which is helpful to identify new prognostic indicators in human diseases and provide potential therapeutic strategies for these diseases.

Research progress in ferroptosis pathways and ubiquitination modification of ferroptosis-related molecules / 中国药理学通报

Ferroptosis is an iron-dependent cell death caused by phospholipid peroxidation damage of polyunsaturated fatty acids on cell membranes and involves several pathways, including the iron homeostasis regulatory pathway, the cystine glutamate reverse transporter (system Xc) pathway and the voltage-dependent anion channel (VDAC) pathway. Ferroptosis is involved in the development of several diseases (e. g. myocardial infarction, stroke, cancer and degenerative diseases). The ubiquitination is an important post-translational modification of various protein molecules in the organism. Studies have shown that regulating the ubiquitination of ferroptosis pathway-related molecules can control cellular ferroptosis. Targeting the ubiquitination of ferroptosis pathway-related molecules can effectively promote or inhibit ferroptosis, which is expected to be a new strategy for the treatment of cancer or cardiovascular diseases. In this paper we review the progress of the ferroptosis pathways and the ubiquitination modification of ferroptosis-related molecules.

Research progress of Parkin protein regulating mitochondrial homeostasis through ubiquitination in cardiovascular diseases / 中国药理学通报

In addition to providing energy for cells, mitochondria also participate in calcium homeostasis, cell information transfer, cell apoptosis, cell growth and differentiation. Therefore, maintaining mitochondrial homeostasis is very crucial for the body to carry out normal life activities. Ubiquitination, a post-translational modification of proteins, is involved in various physiological and pathological processes of cells by regulating mitochondrial homeostasis. However, the mechanism by which ubiquitination regulates mitochondrial homeostasis has not been summarized, especially the effect of Parkin protein on cardiovascular diseases. In this paper, the specific mechanism of mitochondrial homeostasis regulated by ubiquitination of Parkin protein is discussed, and the influence of mitochondrial homeostasis imbalance on cardiovascular diseases is reviewed, with a view to providing potential therapeutic strategies for the clinical treatment of cardiovascular diseases.

Role of post-translational modification of basic leucine zipper transcription factors in response to abiotic stresses in plants / 生物工程学报

Abiotic stresses substantially affect the growth and development of plants. Plants have evolved multiple strategies to cope with the environmental stresses, among which transcription factors play an important role in regulating the tolerance to abiotic stresses. Basic leucine zipper transcription factors (bZIP) are one of the largest gene families. The stability and activity of bZIP transcription factors could be regulated by different post-translational modifications (PTMs) in response to various intracellular or extracellular stresses. This paper introduces the structural feature and classification of bZIP transcription factors, followed by summarizing the PTMs of bZIP transcription factors, such as phosphorylation, ubiquitination and small ubiquitin-like modifier (SUMO) modification, in response to abiotic stresses. In addition, future perspectives were prospected, which may facilitate cultivating excellent stress-resistant crop varieties by regulating the PTMs of bZIP transcription factors.

Advances on BTB protein ubiquitination mediated plant development and stress response / 生物工程学报

The BTB (broad-complex, tramtrack, and bric-à-brac) domain is a highly conserved protein interaction motif in eukaryotes. They are widely involved in transcriptional regulation, protein degradation and other processes. Recently, an increasing number of studies have shown that these genes play important roles in plant growth and development, biotic and abiotic stress processes. Here, we summarize the advances of these proteins ubiquitination-mediated development and abiotic stress responses in plants based on the protein structure, which may facilitate the study of this type of gene in plants.

Hydralazine represses Fpn ubiquitination to rescue injured neurons via competitive binding to UBA52 / 药物分析学报

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 pro-grammed 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 ac-celeration of axon regeneration and motor function recovery.HYD targeting of ferroptosis is a promising strategy for clinical management of PNI.

GLUL stabilizes N-Cadherin by antagonizing β-Catenin to inhibit the progresses of gastric cancer

Glutamate-ammonia ligase (GLUL, also known as glutamine synthetase) is a crucial enzyme that catalyzes ammonium and glutamate into glutamine in the ATP-dependent condensation. Although GLUL plays a critical role in multiple cancers, the expression and function of GLUL in gastric cancer remain unclear. In the present study, we have found that the expression level of GLUL was significantly lower in gastric cancer tissues compared with adjacent normal tissues, and correlated with N stage and TNM stage, and low GLUL expression predicted poor survival for gastric cancer patients. Knockdown of GLUL promoted the growth, migration, invasion and metastasis of gastric cancer cells in vitro and in vivo, and vice versa, which was independent of its enzyme activity. Mechanistically, GLUL competed with β-Catenin to bind to N-Cadherin, increased the stability of N-Cadherin and decreased the stability of β-Catenin by alerting their ubiquitination. Furthermore, there were lower N-Cadherin and higher β-Catenin expression levels in gastric cancer tissues compared with adjacent normal tissues. GLUL protein expression was correlated with that of N-Cadherin, and could be the independent prognostic factor in gastric cancer. Our findings reveal that GLUL stabilizes N-Cadherin by antagonizing β-Catenin to inhibit the progress of gastric cancer.

The deubiquitinating enzyme 13 retards non-alcoholic steatohepatitis via blocking inactive rhomboid protein 2-dependent pathway

Nowadays potential preclinical drugs for the treatment of nonalcoholic steatohepatitis (NASH) have failed to achieve expected therapeutic efficacy because the pathogenic mechanisms are underestimated. Inactive rhomboid protein 2 (IRHOM2), a promising target for treatment of inflammation-related diseases, contributes to deregulated hepatocyte metabolism-associated nonalcoholic steatohepatitis (NASH) progression. However, the molecular mechanism underlying Irhom2 regulation is still not completely understood. In this work, we identify the ubiquitin-specific protease 13 (USP13) as a critical and novel endogenous blocker of IRHOM2, and we also indicate that USP13 is an IRHOM2-interacting protein that catalyzes deubiquitination of Irhom2 in hepatocytes. Hepatocyte-specific loss of the Usp13 disrupts liver metabolic homeostasis, followed by glycometabolic disorder, lipid deposition, increased inflammation, and markedly promotes NASH development. Conversely, transgenic mice with Usp13 overexpression, lentivirus (LV)- or adeno-associated virus (AAV)-driven Usp13 gene therapeutics mitigates NASH in 3 models of rodent. Mechanistically, in response to metabolic stresses, USP13 directly interacts with IRHOM2 and removes its K63-linked ubiquitination induced by ubiquitin-conjugating enzyme E2N (UBC13), a ubiquitin E2 conjugating enzyme, and thus prevents its activation of downstream cascade pathway. USP13 is a potential treatment target for NASH therapy by targeting the Irhom2 signaling pathway.

Construction of TRAF6 ubiquitin site 331 mutant colorectal cancer cell stable line and its effect on biological behavior of colorectal cancer cells / 中华肿瘤杂志

Objective: To investigate the effect of ubiquitin mutation at position 331 of tumor necrosis factor receptor related factor 6 (TRAF6) on the biological characteristics of colorectal cancer cells and its mechanism. Methods: lentivirus wild type (pCDH-3×FLAG-TRAF6) and mutation (pCDH-3×FLAG-TRAF6-331mut) of TRAF6 gene expression plasmid with green fluorescent protein tag were used to infect colorectal cancer cells SW480 and HCT116, respectively. The infection was observed by fluorescence microscope, and the expressions of TRAF6 and TRAF6-331mut in cells was detected by western blot. Cell counting kit-8 (CCK-8) and plate cloning test were used to detect the proliferation ability of colorectal cancer cells in TRAF6 group and TRAF6-331mut group, cell scratch test to detect cell migration, Transwell chamber test to detect cell migration and invasion, immunoprecipitation to detect the ubiquitination of TRAF6 and TRAF6-331mut with ubiquitinof lysine binding sites K48 and K63. Western blot was used to detect the effects of TRAF6 and TRAF6-331mut over expression on the nuclear factor kappa-B (NF-κB) and mitogen activated protein kinase mitogen-activated protein kinase (MAPK)/activating protein-1(AP-1) signal pathway. Results: The successful infection of colorectal cancer cells was observed under fluorescence microscope. Western blot detection showed that TRAF6 and TRAF6-331mut were successfully expressed in colorectal cancer cells. The results of CCK-8 assay showed that on the fourth day, the absorbance values of HCT116 and SW480 cells in TRAF6-331mut group were 1.89±0.39 and 1.88±0.24 respectively, which were lower than those in TRAF6 group (2.09±0.12 and 2.17±0.45, P=0.036 and P=0.011, respectively). The results of plate colony formation assay showed that the number of clones of HCT116 and SW480 cells in TRAF6-331mut group was 120±14 and 85±14 respectively, which was lower than those in TRAF6 group (190±21 and 125±13, P=0.001 and P=0.002, respectively). The results of cell scratch test showed that after 48 hours, the percentage of wound healing distance of HCT116 and SW480 cells in TRAF6-331mut group was (31±12)% and (33±14)%, respectively, which was lower than those in TRAF6 group [(43±13)% and (43±7)%, P=0.005 and 0.009, respectively]. The results of Transwell migration assay showed that the migration numbers of HCT116 and SW480 cells in TRAF6-331mut group were significantly lower than those in TRAF6 group (P<0.001 and P<0.002, respectively). The results of Transwell invasion assay showed that the number of membrane penetration of HCT116 and SW480 cells in TRAF6-331mut group was significantly lower than those in TRAF6 group (P=0.008 and P=0.009, respectively). The results of immunoprecipitation detection showed that the ubiquitin protein of K48 chain pulled by TRAF6-331mut was lower than that of wild type TRAF6 in 293T cells co-transfected with K48 (0.57±0.19), and the ubiquitin protein of K63 chain pulled down by TRAF6-331mut in 293T cells co-transfected with K63 was lower than that of wild type TRAF6 (0.89±0.08, P<0.001). Western blot assay showed that the protein expression levels of NF-κB, p-NF-κB and p-AP-1 in TRAF6-331mut-HCT116 cells were 0.63±0.08, 0.42±0.08 and 0.60±0.07 respectively, which were lower than those in TRAF6-HCT116 cells (P=0.002, P<0.001 and P<0.001, respectively). The expression level of AP-1 protein in TRAF6-HCT116 cells was 0.89±0.06, compared with that in TRAF6-HCT116 cells. The difference was not statistically significant (P>0.05). The protein expression levels of NF-κB, p-NF-κB and p-AP-1 in TRAF6-331mut-SW480 cells were 0.50±0.06, 0.51±0.04, 0.48±0.02, respectively, which were lower than those in TRAF6-SW480 cells (all P<0.001). There was no significant difference in AP-1 protein expression between TRAF6-331mut-SW480 cells and TRAF6-SW480 cells. Conclusion: The ubiquitin site mutation of TRAF6 gene at 331 may prevent the binding of TRAF6 and ubiquitin lysine sites K48 and K63, and then affect the expressions of proteins related to downstream NF-κB and MAPK/AP-1 signal pathways, and inhibit the proliferation, migration and invasion of colorectal cancer cells.

Effects of herbal cake separated moxibustion on Tim-4 and ubiquitination of PD-1 in rabbits with immunosuppression / 中国针灸

OBJECTIVE@#To observe the effects of herbal cake separated moxibustion on macrophage effector molecule T-cell immunoglobulin and mucin-domain containing-4 (Tim-4) and ubiquitination of programmed cell death protein 1 (PD-1) in rabbits with immunosuppression, and to explore the possible mechanism on herbal cake separated moxibustion in improving immunosuppression.@*METHODS@#Thirty-two big-ear white rabbits were randomly divided into a normal group, a model group, a moxa stick moxibustion group and a herbal cake separated moxibustion group, 8 rabbits in each group. Except the normal group, the immunosuppression model was established by intraperitoneal injection of cyclophosphamide of60 mg/kg in the other 3 groups. "Shenque" (CV 8), "Shenshu" (BL 23), "Zusanli" (ST 36), etc. were selected in both the moxa stick moxibustion group and the herbal cake separated moxibustion group. Moxa stick moxibustion was applied in the moxa stick moxibustion group, one cone at each acupoint; herbal cake separated moxibustion was applied in the herbal cake separated moxibustion group, 5 cones at each acupoint. The intervention was given once every other day for 10 times in both groups. Leukocyte content in peripheral blood was detected by blood cell analyzer; the positive expression of PD-1 in CD+4 T lymphocytes, CD+8T lymphocytes and CD+68 macrophages in peripheral blood was measured by flow cytometry, the serum levels of interleukin 2 (IL-2), CD8, CD68 and Tim-4 were detected by ELISA, and the expression of Tim-4 and F-box only protein 38 (FBXO38) in the liver and spleen tissues was measured by immunohistochemistry.@*RESULTS@#Compared with the normal group, in the model group, white blood cell count (WBC) and percentage of neutrophils (NEU%) were decreased while percentage of lymphocyte (LYM%) was increased (P<0.01) in peripheral blood; the positive expression rates of PD-1 in CD+4 T lymphocytes, CD+8T lymphocytes and CD+68 macrophages in peripheral blood were increased (P<0.01); the serum levels of IL-2, CD68 and Tim-4 were increased (P<0.01), the serum level of CD8 was decreased (P<0.01); the average optical density (AOD) of Tim-4 in the liver tissue and FBXO38 in the liver and spleen tissues was increased (P<0.01). Compared with the model group, in the moxa stick moxibustion group and the herbal cake separated moxibustion group, WBC and NEU% were increased (P<0.01); the positive expression rates of PD-1 in CD+4 T lymphocytes, CD+8T lymphocytes and CD+68 macrophages in peripheral blood were decreased (P<0.01); the serum levels of IL-2, CD68 and Tim-4 were decreased (P<0.01), the serum levels of CD8 were increased (P<0.01); the AOD of Tim-4 and FBXO38 in the liver tissue and FBXO38 in the spleen tissue was decreased (P<0.01, P<0.05). Compared with the moxa stick moxibustion group, in the herbal cake separated moxibustion group, the positive expression rate of PD-1 in CD+68 macrophages in peripheral blood was increased (P<0.05); serum level of Tim-4 was increased (P<0.01); AOD of Tim-4 in the liver tissue was decreased (P<0.05).@*CONCLUSION@#Herbal cake separated moxibustion can improve immunosuppression by regulating the expression of macrophage effector molecule Tim-4 and the FBXO38 mediated ubiquitination of PD-1, Tim-4 may be one of the specific indexes of immunomodulation involving with herbal cake separated moxibustion.

Research progress on linear ubiquitin chain assembly complex and OTU deubiquitinase with linear linkage specificity in tumor / 药学实践与服务

Linear ubiquitination is an important post-translational modification that has been discovered in recent years. The linear ubiquitin chain is formed by the linkage of glycine residue of one ubiquitin protein to the methionine residue of another ubiquitin. This process is regulated by the linear ubiquitin chain assembly complex (LUBAC) and the OTU deubiquitinase with linear linkage specificity (OTULIN). Linear ubiquitination is involved in various biological processes, including immune response, inflammation, and cell apoptosis. Recent studies have shown that linear ubiquitination is closely related to the occurrence, development, and drug resistance of tumors by affecting signaling pathways such as NF-κB and Wnt/β-catenin. The research progress on the function of LUBAC and OTULIN in tumors was reviewed in this paper.

The deubiquitinase OTULIN promotes aerobic glycolysis and proliferation of gastric cancer cells / 肿瘤

Objective:To examine the expression of OUT domain deubiquitinase with linear linkage specificity(OTULIN)in gastric cancer tissues and explore the impact of OTULIN silencing on the proliferation of gastric cancer MKN45 and AGS cells as well as its underlying mechanisms. Methods:Immunohistochemical staining was performed to detect the expression level of OTULIN in 73 gastric cancer tissues and 24 normal gastric mucosa.The association between OTULIN expression and the prognosis as well as the clinicopathological features of gastric cancer patients was analyzed.The above results were validated using public data from The Cancer Genome Atlas(TCGA)database and Gene Expression Omnibus(GEO)database.CRISPR/Cas9 gene editing technology was used to construct OTULIN-knockout gastric cancer cells MKN45 and AGS.The efficiency of gene knockout was validated by Western blotting.The effects of OTULIN knockout on the proliferation of gastric cancer cells MKN45 and AGS were assessed by CCK-8 assay and soft agar colony formation assay.Immunoprecipitation-mass spectrometry technique was exploited to identify potential protein substrates interacting with OTULIN and linear ubiquitin molecule INT-Ub.7KR.The changes in the activity of rate-limiting enzymes for glycolysis were measured using pyruvate kinase(PK)activity assay kit and lactate production was analyzed by lactate colorimetric/fluorometric assay kit in OTULIN-depleted cells.The effect of OTULIN on substrate linear ubiquitination was evaluated using co-immunoprecipitation and Western blotting. Results:The expression level of OTULIN in gastric cancer tissues was higher than that in normal gastric mucosa(P=0.004 1)as revealed by immunohistochemical analysis.Patients with higher OTULIN expression in the cancer tissues had a lower suvival time(P=0.007 7).Analysis of datasets from TCGA and GEO databases also confirmed that OTULIN was highly expressed in gastric tissues(P＜0.05)and high OTULIN expression was associated with poor prognosis(P=0.011).Statistical analysis also showed that higher expression of OTULIN was correlated with later TNM stages(P=0.027 3)and was an independent indicator for shorter survival time of gastric cancer patients(P=0.04).Knockout of OTULIN significantly inhibited the proliferation(P＜0.000 1),decreased the activity of PK(P＜0.01)and reduced lactate production(P＜0.01)of gastric cancer cells.OTULIN interacted with several key enzymes in the glycolysis pathway and downregulated the linear ubiquitination levels of these enzymes,including pyruvate kinase M1(PKM1),PKM2,lactate dehydrogenase A(LDHA)and LDHB. Conclusion:OTULIN is a novel biomarker for predicting the prognosis of gastric cancer patients.It activates the glycolytic pathway and promote the progression of gastric cancer possibly by downregulating the linear ubiquitination modification of rate-limiting enzymes in glycolysis.

Effect of icariin on ubiquitination of amyloid precur-sor protein in Alzheimer's disease mice / 中国药理学与毒理学杂志

OBJECTIVE To investigate the effect of icariin(ICA)on the ubiquitination modification of β-amy-loid precursor protein(APP)in Alzheimer's disease mice.METHODS In vitro,① HEK 293 cells stably overex-pressing human APP695(OE-hAPP)were treated with different concentrations of ICA(10-100 μmol·L-1)for 24 h and the cell viability was detected by MTT assay.②CHX(50 mg·L-1)was used to block protein synthesis and MG132(20 μmol·L-1)inhibits proteasome activity,then the level of APP in different time(0,0.5,1,2,3 and 4 h)and the ubiquitination were tested by Western blotting.③ E3 ubiquitin ligases HMG-CoA reductase degradation pro-tein 1(HRD1)protein expression in OE-hAPP was tested by Western blotting,as well as the level and ubiquitination of APP were tested under HRD1 silent condition by Co-IP and Western blotting.In vivo,① male APP/PS1 mice and wild type(WT)mice were randomly divided into 5 groups:WT,WT+ICA,APP/PS1,APP/PS1+ICA,and APP/PS1+donepezil(DPZ)groups.ICA(60 mg·kg-1·d-1)and DPZ(1 mg·kg-1·d-1)were treated for 3 months by gavage from 6 months of age,and WT mice were given equal volume of distilled water.②Morris water maze and Y-maze experiments were used to detect the alteration of spatial learning memory function.③ After then,the brain tissues were collected,total proteins were extracted,APP antibodies were subjected to Co-IP,and total ubiqui-tination(Ub),K48-linked polyubiquitination(UbK48)and K63-linked polyubiquitination of APP level,APP and HRD1 proteins were detected by Western blotting.RESULTS In vitro results showed that ICA significantly enhanced APP degradation(vs control,P＜0.01),up-reg-ulated HRD1 expression(vs control,P＜0.05;vs OE-hAPP,P＜0.05),elevated the level Ub and UbK48 of APP,as well as increased APP degradation.Moreover,silenced HRD1 gene abolished abovementioned effects of ICA(vs control-siRNA,P＜0.05;vs HRD1-siRNA,P＜0.05).In vivo results showed that ICA improved the spa-tial learning and memory function APP/PS1 mice by Mor-ris water maze and Y-maze tests,increased HRD1 expres-sion(vs APP/PS1 + vehicle,P＜0.05),enhanced APP ubiquitination and reduced APP protein level(vs APP/PS1 + vehicle,P＜0.01).CONCLUSION ICA promotes the ubiquitination and proteasome-dependent degrada-tion of APP by up-regulating HRD1,thereby improving the spatial learning and memory function of Alzheimer disease mice.

Protein phosphorylation involved in psychedelic-induced head-twitch response in rats / 中国药理学通报

Aim To investigate the potential protein post-translational modifications of psychedelic-induced Head-twith response and underling mechanism. Methods Psychedelics LSD, DOM, or Psilocin was administered to rats by intraperitoneal injection to induce head-twitch response, then the most effective dosage was identified to create animal models of head-twitch behavior. Western blot was performed in detecting the protein phosphorylation, acetylation, and ubiquitination in prefrontal cortex of SD rats after 10 min or 30 min injection. Results LSD (0.025 mg • kg~, i. p.), DOM (3 mg•kg

Mechanism of nitidine chloride inducing apoptosis of cervical cancer cells by inhibiting p53 ubiquitination degradation / 中国药理学通报

Aim To investigate the effect of nitidine chloride (NC) on the apoptosis of cervical cancer cells and its mechanism. Methods Cervical cancer cell lines HeLa and SiHa were selected as subjects. The cytotoxicity of NC and its inhibitory effect on cell growth were detected by CCK-8 assay and clone formation assay. The effect of NC on the apoptosis of cervical cancer cells was detected by TUNEL assay, and the expression of apoptosis-related proteins was detected by Western blot. The effects of NC on the interaction between p53 and E6AP protein, the level of p53 ubiquitination modification and the stability of p53 protein in cervical cancer cells were analyzed by immunoprecipi-tation assay, ubiquitination assay and Western blot assay. Results NC could significantly inhibit the proliferation and induce apoptosis of cervical cancer cells. NC could inhibit the interaction between tumor suppressor protein p53 and E6AP in cervical cancer cells, reduce the level of p53 ubiquitination modification, delay the degradation of p53 and increase the expression level of p53 protein. Conclusions NC can inhibit the ubiquitination and degradation of p53, improve the expression level of p53 protein, restore its tumor suppressor function, and thus play an anti -cervical cancer role.

Mechanism of cucurbitacin B suppresses proliferation of hepatocellular carcinoma Huh-7 cells via inducing ferroptosis / 中国药理学通报

Aim To study the effects of cucurbitacin B (Cu B) on proliferation of hepatocellular carcinoma Huh-7 cells and its mechanism. Methods CCK-8 was used to detect the survival rate of Huh-7 cells with different concentrations of Cu B. Huh-7 cells were treated with Cu B (0. 5, 1, 2 njnol; L

Recent developments on transition of lung myofibroblasts / 中国药理学通报

Lung myofibroblasts are important effector that drive the development of idiopathic pulmonary fibrosis, but the mechanisms of lung myofibroblasts transition have not been clarified yet. In this review, we summarize the progress on the mechanisms of lung myofibroblast transitionfrom the aspects of mechanical transduction, metabolism, oxidative stress, ubiquitination and cell senescence in the past five years.