摘要
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.
摘要
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.
摘要
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.
摘要
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.
摘要
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.
摘要
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.
摘要
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.
摘要
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.
摘要
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.
Subject(s)
Basic-Leucine Zipper Transcription Factors/genetics , Protein Processing, Post-Translational , Phosphorylation , Transcription Factors/genetics , Stress, Physiological/genetics摘要
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.
Subject(s)
Eukaryota , Plant Development/genetics , Proteolysis , Ubiquitination摘要
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.
摘要
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.
摘要
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.
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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.
Subject(s)
Humans , Cell Line, Tumor , Cell Movement , Cell Proliferation , Colorectal Neoplasms/pathology , Lysine/metabolism , NF-kappa B/metabolism , TNF Receptor-Associated Factor 6/metabolism , Transcription Factor AP-1/metabolism , Ubiquitin/metabolism摘要
Triple-negative breast cancer (TNBC) is a nasty disease with extremely high malignancy and poor prognosis. Annexin A3 (ANXA3) is a potential prognosis biomarker, displaying an excellent correlation of ANXA3 overexpression with patients' poor prognosis. Silencing the expression of ANXA3 effectively inhibits the proliferation and metastasis of TNBC, suggesting that ANXA3 can be a promising therapeutic target to treat TNBC. Herein, we report a first-in-class ANXA3-targeted small molecule (R)-SL18, which demonstrated excellent anti-proliferative and anti-invasive activities to TNBC cells. (R)-SL18 directly bound to ANXA3 and increased its ubiquitination, thereby inducing ANXA3 degradation with moderate family selectivity. Importantly, (R)-SL18 showed a safe and effective therapeutic potency in a high ANXA3-expressing TNBC patient-derived xenograft model. Furthermore, (R)-SL18 could reduce the β-catenin level, and accordingly inhibit the Wnt/β-catenin signaling pathway in TNBC cells. Collectively, our data suggested that targeting degradation of ANXA3 by (R)-SL18 possesses the potential to treat TNBC.
摘要
Acetaminophen (APAP) overdose is a major cause of liver injury. Neural precursor cell expressed developmentally downregulated 4-1 (NEDD4-1) is an E3 ubiquitin ligase that has been implicated in the pathogenesis of numerous liver diseases; however, its role in APAP-induced liver injury (AILI) is unclear. Thus, this study aimed to investigate the role of NEDD4-1 in the pathogenesis of AILI. We found that NEDD4-1 was dramatically downregulated in response to APAP treatment in mouse livers and isolated mouse hepatocytes. Hepatocyte-specific NEDD4-1 knockout exacerbated APAP-induced mitochondrial damage and the resultant hepatocyte necrosis and liver injury, while hepatocyte-specific NEDD4-1 overexpression mitigated these pathological events both in vivo and in vitro. Additionally, hepatocyte NEDD4-1 deficiency led to marked accumulation of voltage-dependent anion channel 1 (VDAC1) and increased VDAC1 oligomerization. Furthermore, VDAC1 knockdown alleviated AILI and weakened the exacerbation of AILI caused by hepatocyte NEDD4-1 deficiency. Mechanistically, NEDD4-1 was found to interact with the PPTY motif of VDAC1 through its WW domain and regulate K48-linked ubiquitination and degradation of VDAC1. Our present study indicates that NEDD4-1 is a suppressor of AILI and functions by regulating the degradation of VDAC1.
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Pulmonary fibrosis (PF) is the pathological structure of incurable fibroproliferative lung diseases that are attributed to the repeated lung injury-caused failure of lung alveolar regeneration (LAR). Here, we report that repetitive lung damage results in a progressive accumulation of the transcriptional repressor SLUG in alveolar epithelial type II cells (AEC2s). The abnormal increased SLUG inhibits AEC2s from self-renewal and differentiation into alveolar epithelial type I cells (AEC1s). We found that the elevated SLUG represses the expression of the phosphate transporter SLC34A2 in AEC2s, which reduces intracellular phosphate and represses the phosphorylation of JNK and P38 MAPK, two critical kinases supporting LAR, leading to LAR failure. TRIB3, a stress sensor, interacts with the E3 ligase MDM2 to suppress SLUG degradation in AEC2s by impeding MDM2-catalyzed SLUG ubiquitination. Targeting SLUG degradation by disturbing the TRIB3/MDM2 interaction using a new synthetic staple peptide restores LAR capacity and exhibits potent therapeutic efficacy against experimental PF. Our study reveals a mechanism of the TRIB3-MDM2-SLUG-SLC34A2 axis causing the LAR failure in PF, which confers a potential strategy for treating patients with fibroproliferative lung diseases.
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Insulin-like growth factor-1 receptor (IGF-1R) has been made an attractive anticancer target due to its overexpression in cancers. However, targeting it has often produced the disappointing results as the role played by cross talk with numerous downstream signalings. Here, we report a disobliging IGF-1R signaling which promotes growth of cancer through triggering the E3 ubiquitin ligase MEX3A-mediated degradation of RIG-I. The active β-arrestin-2 scaffolds this disobliging signaling to talk with MEX3A. In response to ligands, IGF-1Rβ activated the basal βarr2 into its active state by phosphorylating the interdomain domain on Tyr64 and Tyr250, opening the middle loop (Leu130‒Cys141) to the RING domain of MEX3A through the conformational changes of βarr2. The models of βarr2/IGF-1Rβ and βarr2/MEX3A could interpret the mechanism of the activated-IGF-1R in triggering degradation of RIG-I. The assay of the mutants βarr2Y64A and βarr2Y250A further confirmed the role of these two Tyr residues of the interlobe in mediating the talk between IGF-1Rβ and the RING domain of MEX3A. The truncated-βarr2 and the peptide ATQAIRIF, which mimicked the RING domain of MEX3A could prevent the formation of βarr2/IGF-1Rβ and βarr2/MEX3A complexes, thus blocking the IGF-1R-triggered RIG-I degradation. Degradation of RIG-I resulted in the suppression of the IFN-I-associated immune cells in the TME due to the blockade of the RIG-I-MAVS-IFN-I pathway. Poly(I:C) could reverse anti-PD-L1 insensitivity by recovery of RIG-I. In summary, we revealed a disobliging IGF-1R signaling by which IGF-1Rβ promoted cancer growth through triggering the MEX3A-mediated degradation of RIG-I.
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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.
摘要
Neuropathic pain is a common chronic pain that affects human health worldwide. As an important mediator of excitatory conduction in neurons, ion channels are important targets for mechanism research and drug research in this field. T-type calcium channel(Cav3) can be activated transiently when neurons are close to the resting potential of -70 mV, resulting in a transient Ca