The phthalide compound tokinolide B from Angelica sinensis exerts anti-inflammatory effects through Nur77 binding.

BACKGROUND: Nur77, an orphan member of the nuclear receptor superfamily, regulates inflammatory diseases and is a therapeutic target for treating inflammation. Phthalides in Angelica sinensis exhibit anti-inflammatory activity. PURPOSE: This study aimed to screen compounds from A. sinensis phthalide extract that could exert anti-inflammatory activity by targeting Nur77. To provide new theoretical support for better elucidation of Chinese medicine targeting mitochondria to achieve multiple clinical efficacies. METHODS: The anti-inflammatory capacity of phthalides was assessed in tumor necrosis factor-alpha (TNF-α)-stimulated HepG2 cells using western blotting. The interaction between phthalides and Nur77 was verified by molecular docking, surface plasmon resonance, and cellular thermal shift assay. Co-immunoprecipitation, western blotting, and immunostaining were performed to determine the molecular mechanisms. The in vivo anti-inflammatory activity of the phthalides was evaluated in a lipopolysaccharide (LPS)/d-galactosamine (d-GalN)-induced acute hepatitis and liver injury mouse model of acute hepatitis and liver injury. Finally, the toxicity of phthalide toxicity was assessed in zebrafish experiments. RESULTS: Among the 27 phthalide compounds isolated from A. sinensis, tokinolide B (TB) showed the best Nur77 binding capacity and, the best anti-inflammatory activity, which was induced without apoptosis. In vivo and in vitro experiments showed that TB promoted Nur77 translocation from the nucleus to the mitochondria and interacted with tumor necrosis factor receptor-associated factor 2 (TRAF2) and sequestosome 1 (p62) to induce mitophagy for anti-inflammatory functions. TB substantially inhibited LPS/d-GalN-induced acute hepatitis and liver injury in mice. TB also exhibited significantly lower toxicity than celastrol in zebrafish experiments. CONCLUSION: These findings suggested that TB inhibits inflammation by promoting Nur77 interaction with TRAF2 and p62, thereby inducing mitophagy. These findings offer promising directions for developing novel anti-inflammatory agents, enhance the understanding of phthalide compounds, and highlight the therapeutic potential of traditional Chinese herbs.

USP24 promotes hepatocellular carcinoma tumorigenesis through deubiquitinating and stabilizing TRAF2.

Ubiquitin-specific peptidase 24 (USP24), a member of the deubiquitinase family, plays an important role in tumor regulation. However, the role of USP24 in Hepatocellular carcinoma（HCC）is unknown. The aim of our study was to explore the role of USP24 in HCC to seek new therapeutic targets for HCC. In this study, we found that USP24 was aberrantly upregulated in HCC tissues and predicted poor prognosis. USP24 markedly promoted HCC proliferation and progression in vitro and in vivo. Mechanistically, USP24 binds to tumor necrosis factor receptor-associated factor 2(TRAF2) and inhibits its degradation, thereby promoting the accumulation of TRAF2. Upregulation of TRAF2 activated protein kinase B/nuclear factor kappa-B (AKT/ NF-κB) signaling pathway and promoted HCC cell survival. In addition, USP24 positively correlated with programmed cell death ligand 1(PD-L1) expression in HCC, highlighting the clinical significance of USP24 activation in tumor immune evasion. Deletion of USP24 enhanced the tumor-killing ability of CD8+ T cells. Deletion of USP24 combined with anti-PD-1 antibody significantly enhanced the efficacy of HCC immunotherapy. Taken together, USP24 can be employed as a promising target to restrain tumor growth and increase the efficacy of HCC immunotherapy.

TRAF2 associates with cullin neddylation complex assembly.

Cullin-based RING ligases (CRLs) comprise the largest family of ubiquitin E3 ligases. CRL activity is tightly regulated by cullin neddylation, which has been associated with various diseases. Although inhibitors of CRLs neddylation have been reported, there is a lack of small molecules that can selectively target individual cullins. Here, we identified a natural product, liquidambaric acid (LDA), with relatively selective inhibition properties against cullin (Cul) 2 neddylation, and found that its target, Tumor Necrosis Factor receptor-associated factor 2 (TRAF2) was required for the activity. TRAF2 associates with the Cul2 neddylation complex and regulates the machinery assembly, especially that of E2 (UBC12) and E3 (RBX1) enzymes. In addition, we demonstrated that by intervention of the associations between TRAF2 and the neddylation machinery, LDA disturbed NEDD8 transfer from E1 to E2, therefore blocking Cul2 neddylation. Taken together, we show that TRAF2 plays a positive role in neddylation cascades, and we have identified a small molecule capable of selective modulation of cullin neddylation.

Associations of TRAF2 (rs867186), TAB2 (rs237025), IKBKB (rs13278372) Polymorphisms and TRAF2, TAB2, IKBKB Protein Levels with Clinical and Morphological Features of Pituitary Adenomas.

AIM: The aim of this study was to determine associations of TRAF2 (rs867186), TAB2 (rs237025), IKBKB (rs13278372) gene polymorphisms and TRAF2, TAB2, IKBKB protein levels with clinical and morphological features of pituitary adenomas (PAs). METHODS: This case-control study included 459 individuals divided into two groups: a control group (n = 320) and a group of individuals with PAs (n = 139). DNA from peripheral blood leukocytes was isolated using salt precipitation and column method. Real-time PCR was used for TRAF2 (rs867186), TAB2 (rs237025), and IKBKB (rs13278372) SNP genotyping, and TRAF2, TAB2, IKBKB protein concentration measurements were performed by immunoenzymatic analysis tests using a commercial ELISA kit according to the manufacturer's recommendations. The labeling index Ki-67 was determined by immunohistochemical analysis using a monoclonal antibody (clone SP6; Spring Bioscience Corporation). Statistical data analysis was performed using the programs "IMB SPSS Statistics 29.0". RESULTS: We found significant differences in TRAF2 (rs867186) genotypes (AA, AG, GG) between groups: 79.1%, 17.3%, 3.6% vs. 55.3%, 20.9%, 23.8% (p < 0.001). The G allele was less frequent in the PA group than in controls (12.2% vs. 34.2%, p < 0.001). The AG and GG genotypes reduced PA occurrence by 1.74-fold and 9.43-fold, respectively, compared to AA (p < 0.001). In the dominant model, GG and AG genotypes reduced PA odds by 3.07-fold, while in the recessive model, the GG genotype reduced PA odds by 8.33-fold (p < 0.001). Each G allele decreased PA odds by 2.49-fold in the additive model (p < 0.001). Microadenomas had significant genotype differences compared to controls: 81.3%, 18.8%, 0.0% vs. 55.3%, 20.9%, 23.8% (p < 0.001), with the G allele being less frequent (9.4% vs. 34.2%, p < 0.001). In macroadenomas, genotype differences were 78%, 16.5%, 5.5% vs. 55.3%, 20.9%, 23.8% (p < 0.001), and the G allele was less common (13.7% vs. 34.2%, p < 0.001). The dominant model showed that GG and AG genotypes reduced microadenoma odds by 3.5-fold (p = 0.001), and each G allele reduced microadenoma odds by 3.1-fold (p < 0.001). For macroadenomas, the GG genotype reduced odds by 6.1-fold in the codominant model (p < 0.001) and by 2.9-fold in GG and AG genotypes combined compared to AA (p < 0.001). The recessive model indicated the GG genotype reduced macroadenoma odds by 5.3-fold (p < 0.001), and each G allele reduced odds by 2.2-fold in the additive model (p < 0.001). CONCLUSIONS: The TRAF2 (rs867186) G allele and GG genotype are significantly associated with reduced odds of pituitary adenomas, including both microadenomas and macroadenomas, compared to the AA genotype. These findings suggest a protective role of the G allele against the occurrence of these tumors.

Ginsenoside Rb1 reduced ischemic stroke-induced apoptosis through endoplasmic reticulum stress-associated IRE1/TRAF2/JNK pathway.

The neuroprotective function of ginsenoside Rb1 (GRb1) in cerebral ischemia-reperfusion (I/R) was lately emphasized. However, whether GRb1 plays a regulatory role on endoplasmic reticulum (ER) stress-associated pathway in cerebral I/R damage is still unclear. The aim of this study is to explore the function of GRb1 in cerebral ischemia-induced ER stress and the underlying mechanism related to IRE1/TRAF2/JNK pathway. Longa method, cerebral infarct volume, and HE staining were used to evaluate the efficacy of GRb1 in mice with a mouse model of middle cerebral artery occlusion reperfusion (MCAO/R). We also investigated the effect and mechanism of GRb1 against ischemic stroke using in vitro oxygen-glucose deprivation reperfusion (OGD/R) model. We found that GRb1 could improve neurological scores, infarct volume, and histological injury in ischemic mice. Ischemic attack also activated neuronal apoptosis and ER stress, and this effect was attenuated by GRb1. In addition, GRb1 significantly reduced I/R-induced IRE1-TRAF2 interaction, IRE1, and JNK phosphorylation. The present study also confirmed that GRb1 significantly improved OGD/R-induced PC12 cells injury. GRb1 could decrease ER stress in OGD/R-injured PC12 cells, which was reflected by the decreased expression of GRP78 and CHOP. The ER stress inducer tunicamycin partially prevented the effects of GRb1 on cell viability, ER stress, and apoptosis after OGD/R, whereas the ER stress inhibitor 4-PBA exerted the opposite effect. Moreover, GRb1 markedly decreased IRE1-TRAF2 interaction, IRE1, and JNK phosphorylation in the presence of OGD/R insult. Furthermore, JNK inhibitor SP600125 and IRE1 inhibitor DBSA pretreatment further promoted the inhibition of GRb1 on ER stress induction and cell damage induced by OGD/R. Molecular docking further elucidated that the mechanism by which GRb1 improves cerebral ischemia maybe related to its direct binding to the kinase domain of IRE1, which in turn inhibited the phosphorylation of IRE1. Collectively, these results demonstrated that GRb1 reduced ischemic stroke-induced apoptosis through the ER stress-associated IRE1/TRAF2/JNK pathway and GRb1 has the potential as a protective drug for the treatment of cerebral ischemia.

Molecular signatures in prion disease: altered death receptor pathways in a mouse model.

BACKGROUND: Prion diseases are transmissible and fatal neurodegenerative diseases characterized by accumulation of misfolded prion protein isoform (PrPSc), astrocytosis, microgliosis, spongiosis, and neurodegeneration. Elevated levels of cell membrane associated PrPSc protein and inflammatory cytokines hint towards the activation of death receptor (DR) pathway/s in prion diseases. Activation of DRs regulate, either cell survival or apoptosis, autophagy and necroptosis based on the adaptors they interact. Very little is known about the DR pathways activation in prion disease. DR3 and DR5 that are expressed in normal mouse brain were never studied in prion disease, so also their ligands and any DR adaptors. This research gap is notable and investigated in the present study. METHODS: C57BL/6J mice were infected with Rocky Mountain Laboratory scrapie mouse prion strain. The progression of prion disease was examined by observing morphological and behavioural abnormalities. The levels of PrP isoforms and GFAP were measured as the marker of PrPSc accumulation and astrocytosis respectively using antibody-based techniques that detect proteins on blot and brain section. The levels of DRs, their glycosylation and ectodomain shedding, and associated factors warrant their examination at protein level, hence western blot analysis was employed in this study. RESULTS: Prion-infected mice developed motor deficits and neuropathology like PrPSc accumulation and astrocytosis similar to other prion diseases. Results from this research show higher expression of all DR ligands, TNFR1, Fas and p75NTR but decreased levels DR3 and DR5. The levels of DR adaptor proteins like TRADD and TRAF2 (primarily regulate pro-survival pathways) are reduced. FADD, which primarily regulate cell death, its level remains unchanged. RIPK1, which regulate pro-survival, apoptosis and necroptosis, its expression and proteolysis (inhibits necroptosis but activates apoptosis) are increased. CONCLUSIONS: The findings from the present study provide evidence towards the involvement of DR3, DR5, DR6, TL1A, TRAIL, TRADD, TRAF2, FADD and RIPK1 for the first time in prion diseases. The knowledge obtained from this research discuss the possible impacts of these 16 differentially expressed DR factors on our understanding towards the multifaceted neuropathology of prion diseases and towards future explorations into potential targeted therapeutic interventions for prion disease specific neuropathology.

B(a)P induces ovarian granulosa cell apoptosis via TRAF2-NFκB-Caspase1 axis during early pregnancy.

Benzo(a)pyrene [B(a)P] is an environmental endocrine disruptor with reproductive toxicity. The corpus luteum (CL) of the ovary plays an important role in embryo implantation and pregnancy maintenance. Our previous studies have shown that B(a)P exposure affects embryo implantation and endometrial decidualization in mouse, but its effects and mechanisms on CL function remain unclear. In this study, we explore the mechanism of ovarian toxicity of B(a)P using a pregnant mouse model and an in vitro model of human ovarian granulosa cells (GCs) KGN. Pregnant mice were gavaged with corn oil or 0.2 mg/kg.bw B(a)P from pregnant day 1 (D1) to D7, while KGN cells were treated with DMSO, 1.0IU/mL hCG, or 1.0IU/mL hCG plus benzo(a)pyrene-7,8-dihydrodiol-9,10-epoxide (BPDE), a B(a)P metabolite. Our findings revealed that B(a)P exposure damaged embryo implantation and reduced estrogen and progesterone levels in early pregnant mice. Additionally, in vitro, BPDE impaired luteinization in KGN cells. We observed that B(a)P/BPDE promoted oxidative stress (OS) and inflammation, leading to apoptosis rather than pyroptosis in ovaries and luteinized KGN cells. This apoptotic response was mediated by the activation of inflammatory Caspase1 through the cleavage of BID. Furthermore, B(a)P/BPDE inhibited TRAF2 expression and suppressed NFκB signaling pathway activation. The administration of VX-765 to inhibit the Caspase1 activation, over-expression of TRAF2 using TRAF2-pcDNA3.1 (+) plasmid, and BetA-induced activation of NFκB signaling pathway successfully alleviated BPDE-induced apoptosis and cellular dysfunction in luteinized KGN cells. These findings were further confirmed in the KGN cell treated with H2O2 and NAC. In conclusion, this study elucidated that B(a)P/BPDE induces apoptosis rather than pyroptosis in GCs via TRAF2-NFκB-Caspase1 during early pregnancy, and highlighting OS as the primary contributor to B(a)P/BPDE-induced ovarian toxicity. Our results unveil a novel role of TRAF2-NFκB-Caspase1 in B(a)P-induced apoptosis and broaden the understanding of mechanisms underlying unexplained luteal phase deficiency.

USP2 Promotes the Proliferation and Inflammation of Fibroblast-Like Synovial Cells in Rheumatoid Arthritis Through Deubiquitination of TRAF2.

Rheumatoid arthritis (RA) is a prevalent inflammatory disorder affecting about 1% of the global population. The ubiquitin-specific protease 2 (USP2) is known to have a substantial influence on the regulation of several cellular processes. Both in vivo (using rats with collagen-induced arthritis, CIA) and in vitro (using human fibroblast-like synoviocytes, HFLS-RA) models of RA were used to examine the role of USP2 in RA. The proliferation of HFLS-RA cells was assessed using the cell counting kit 8 test and EdU staining. The technique used for the assessment of gene expression was quantitative real-time PCR. Protein expression was quantified using Western blot (WB) analysis, while the quantities of inflammatory factors and matrix metalloproteinases were assessed using an ELISA test. The co-immunoprecipitation and ubiquitination tests investigated the relationships between proteins and the underlying molecular pathways. The results of this study demonstrate an upregulation of USP2 expression in both vivo and vitro models of RA. In addition, our findings indicate that the overexpression of USP2 notably exacerbates both proliferation and inflammation. The consistent downregulation of USP2 resulted in a reduction in the secretion of inflammatory cytokines and a suppression of cellular proliferation. Furthermore, it was shown that USP2 interacts with tumor necrosis factor receptor-associated factor 2 (TRAF2) and facilitates the removal of ubiquitination chains from TRAF2, enhancing its stability. Our findings propose that USP2 functions as a favorable modulator of proliferation and inflammatory reactions in HFLS-RA, thereby indicating its potential as a therapeutic target for the treatment of RA.

TRAF2 decrease promotes the TGF-ß-mTORC1 signal in MAFLD-HCC through enhancing AXIN1-mediated Smad7 degradation.

According to recent research, metabolic-associated fatty liver disease (MAFLD) has emerged as an important underlying etiology of hepatocellular carcinoma (HCC). However, the molecular mechanism of MAFLD-HCC is still unclear. Tumor necrosis factor receptor-associated factor 2 (TRAF2) is the key molecule to mediate the signal of inflammatory NF-κB pathway. This study aims to investigate the potential dysregulation of TRAF2 and its biological function in MAFLD-HCC. Huh7 TRAF2-/- demonstrated increased tumor formation ability compared to huh7 TRAF2+/+ when stimulated with transforming growth factor-ß (TGF-ß). The decisive role of TGF-ß in the development of MAFLD-HCC was confirmed through the specific depletion of TGF-ß receptor II gene in the hepatocytes (Tgfbr2ΔHep) of mice. In TRAF2-/- cells treated with TGF-ß, both the glycolysis rate and lipid synthesis were enhanced. We proved the signal of the mechanistic target of rapamycin complex 1 (mTORC1) could be activated in the presence of TGF-ß, and was enhanced in TRAF2-/- cells. The coimmunoprecipitation (co-IP) experiments revealed that TRAF2 fortified the Smurf2-mediated ubiquitination degradation of AXIN1. Hence, TRAF2 depletion resulted in increased Smad7 degradation induced by AXIN1, thus promoting the TGF-ß signal. We also discovered that PLX-4720 could bind with AXIN1 and restrained the tumor proliferation of TRAF2-/- in mice fed with high-fat diet (HFD). Our findings indicate that TRAF2 plays a significant role in the pathogenesis of MAFLD-HCC. The reduction of TRAF2 expression leads to the enhancement of the TGF-ß-mTORC1 pathway by facilitating AXIN1-mediated Smad7 degradation.

The Traf2 and NcK interacting kinase inhibitor NCB-0846 suppresses seizure activity involving the decrease of GRIA1.

Epilepsy, one of the most common neurological disorders, is characterized by spontaneous recurrent seizures. Temporal lobe epilepsy (TLE) is one of the most common medically intractable seizure disorders. Traf2-and NcK-interacting kinase (TNIK) has recently attracted attention as a critical modulation target of many neurological and psychiatric disorders, but its role in epilepsy remains unclear. In this study, we hypothesized the involvement of TNIK in epilepsy and investigated TNIK expression in patients with intractable TLE and in a pilocarpine-induced rat model of epilepsy by western blotting, immunofluorescence, and immunohistochemistry. A pentylenetetrazole (PTZ)-induced epilepsy rat model was used to determine the effect of the TNIK inhibitor NCB-0846 on behavioral manifestations of epilepsy. Coimmunoprecipitation (Co-IP)/mass spectrometry (MS) was used to identify the potential mechanism. Through Co-IP, we detected and confirmed the main potential TNIK interactors. Subcellular fractionation was used to establish the effect of NCB-0846 on the expression of the main interactors in postsynaptic density (PSD) fractions. We found that TNIK was primarily located in neurons and decreased significantly in epilepsy model rats and TLE patients compared with controls. NCB-0846 delayed kindling progression and decreased seizure severity. Co-IP/MS identified 63 candidate TNIK interactors in rat hippocampi, notably CaMKII. Co-IP showed that TNIK might correlate with endogenous GRIA1, SYN2, PSD-95, CaMKIV, GABRG1, and GABRG2. In addition, the significant decrease in GRIA1 in hippocampal total lysate and PSDs after NCB-0846 treatment might help modify the progression of PTZ kindling. Our results suggest that TNIK contributes to epileptic pathology and is a potential antiepileptic drug target.

Oncogenic KEAP1 mutations activate TRAF2-NFκB signaling to prevent apoptosis in lung cancer cells.

The Kelch-like ECH-associated protein 1 (KEAP1) - Nuclear factor erythroid 2 -related factor 2 (NRF2) pathway is the major transcriptional stress response system in cells against oxidative and electrophilic stress. NRF2 is frequently constitutively active in many cancers, rendering the cells resistant to chemo- and radiotherapy. Loss-of-function (LOF) mutations in the repressor protein KEAP1 are common in non-small cell lung cancer, particularly adenocarcinoma. While the mutations can occur throughout the gene, they are enriched in certain areas, indicating that these may have unique functional importance. In this study, we show that in the GSEA analysis of TCGA lung adenocarcinoma RNA-seq data, the KEAP1 mutations in R320 and R470 were associated with enhanced Tumor Necrosis Factor alpha (TNFα) - Nuclear Factor kappa subunit B (NFκB) signaling as well as MYC and MTORC1 pathways. To address the functional role of these hotspot mutations, affinity purification and mass spectrometry (AP-MS) analysis of wild type (wt) KEAP1 and its mutation forms, R320Q and R470C were employed to interrogate differences in the protein interactome. We identified TNF receptor associated factor 2 (TRAF2) as a putative protein interaction partner. Both mutant KEAP1 forms showed increased interaction with TRAF2 and other anti-apoptotic proteins, suggesting that apoptosis signalling could be affected by the protein interactions. A549 lung adenocarcinoma cells overexpressing mutant KEAP1 showed high TRAF2-mediated NFκB activity and increased protection against apoptosis, XIAP being one of the key proteins involved in anti-apoptotic signalling. To conclude, KEAP1 R320Q and R470C and its interaction with TRAF2 leads to activation of NFκB pathway, thereby protecting against apoptosis.

TRAF2 inhibits senescence in hepatocellular carcinoma cells via regulating the ROMO1/ NAD+/SIRT3/SOD2 axis.

The suppression of tumor proliferation via cellular senescence has emerged as a promising approach for anti-tumor therapy. Tumor necrosis factor receptor-associated factor 2 (TRAF2), an adaptor protein involved in the NF-κB signaling pathway and reactive oxygen species (ROS) production, has been implicated in hepatocellular carcinoma (HCC) proliferation. However, little is currently known about whether TRAF2 promotes HCC development by inhibiting cellular senescence. Replicative senescence model and IR-induced mouse model demonstrated that TRAF2 expression was decrease in senescence cells or liver tissues. Depletion of TRAF2 could inhibit proliferation and arrest the cell cycle via activating p53/p21WAF1 and p16INK4a/pRb signaling pathways in HCC cells and eventually lead to cellular senescence. Mechanistically, TRAF2 deficiency increased the expression of mitochondrial protein reactive oxygen species modulator 1 (ROMO1) and subsequently activated the NAD+/SIRT3/SOD2 pathway to promote the production of ROS and cause mitochondrial dysfunction, which eventually contributed to DNA damage response (DDR). Our findings demonstrate that TRAF2 deficiency inhibits the proliferation of HCC by promoting senescence. Therefore, targeting TRAF2 through various approaches holds therapeutic potential for treating HCC.

Mechanistic study of tripterygium glycosides in the treatment of ulcerative colitis through the Nur77-Traf2-P62 signaling pathway / 中国现代医生

@#Objective To investigated the effect of tripterygium glycosides(TG)on dextran sodium sulfate(DSS)-induced colonic mucosal damage in ulcerative colitis(UC)mice and its regulatory mechanism.Methods Forty C57BL/6J mice were randomly divided into a normal group,a model group,and a tretinoin low,medium,and high dose group(administered at concentrations of 9.00mg/kg,27.03mg/kg,and 81.09mg/kg,respectively).The mice in the normal group were free to drink distilled water,and the rest of the mice drank 5％DSS to induce UC modeling.After modeling,mice in the model group were given 0.4ml of saline by gavage daily,and the rest of the mice in the treatment group were given the corresponding dose of TG for gavage intervention.The mass and disease activity index of the mice in each group were compared,and the pathological and histological damage of the colon was observed.Tumor necrosis factor-α(TNF-α),malondialdehyde(MDA),and superoxide dismutase(SOD)levels were measured using the corresponding kits.Western blot Detection of Nur77,tumor necrosis factor receptor-associated factor 2(Traf2),nucleoporin 62(P62),autophagy protein-microtubule associated protein1 light chain 3(LC3)molecular expression.Results Compared with the blank group,the body weight,colon length,SOD,Nur77,Traf2,and LC3Ⅱ/LC3Ⅰ levels of mice in the model group were significantly decreased(P<0.05),and the DAI level,colon pathology score,TNF-α,MDA level,and P62 of the mice were significantly increased(P<0.05).Compared with mice in the UC model group,mice in the low,medium and high dose groups of tretinoin polyphenols showed significant increases in body weight,colon length,SOD,Nur77,Traf2,LC3Ⅱ/LC3Ⅰlevels(P<0.05),and mice with DAI scores,TNF-α,MDA levels in the colon,and P62 levels were significantly decreased(P<0.05).Mice in the medium and high dose groups of tretinoin polyphenols pathological scores were significantly reduced(P<0.05).Conclusion TG is able to treat ulcerative colitis through Nur77-Traf2-P62 signaling pathway.

TRAIP suppressed apoptosis and cell cycle to promote prostate cancer proliferation via TRAF2-PI3K-AKT pathway activation.

BACKGROUND: TRAF-interacting protein (TRAIP) is a RING-type E3 ubiquitin ligase, which has been implicated in various cellular processes and participated in various cancers as an oncogene. However, the function and potential mechanism of TRAIP in prostate cancer (PCa) have not been investigated so far. METHODS: Public TGCA data were used to evaluate the expression profile of TRAIP in prostatic tumors. The relative expression of TRAIP and TRAF2 in PCa tissues and tumor cell lines was detected by qPCR, western blot, and IHC staining. Next, TRAIP knockdown and overexpression plasmids were constructed and transfected into PCa cell lines. Moreover, cell proliferation, invasion, migration, and apoptosis were measured by colony formation, Transwell, wound healing, and flow cytometry assays. Subsequently, cell cycle and signaling pathway-related proteins were tested by western blot. Finally, the effect of TRAIP on PCa was measured based on the nude mouse xenograft model. RESULTS: TRAIP was significantly upregulated in PCa tissues and tumor cell lines. In addition, TRAIP promoted cell proliferation, invasion, and migration of PCa cell lines. Such an oncogenic property was mediated by the cell cycle arrest and the inhibition of apoptosis, as indicated by different functional assays and the expression of cell cycle and apoptosis regulatory proteins in cultured cells. Moreover, TRAIP combined with TRAF2 to activate PI3K/AKT pathway. Finally, TRAIP depletion suppressed the growth of tumors and cell proliferation in vivo. CONCLUSIONS: Our study first revealed that TRAIP promoted tumor progression and identified it as a potential therapeutic target for PCa patients in the future.

Molecular and cellular evidence of a direct interaction between the TRAF2 C-terminal domain and ganglioside GM1.

TNF receptor-associated factor 2 (TRAF2) is involved in different cellular processes including signal transduction and transcription regulation. We here provide evidence of a direct interaction between the TRAF domain of TRAF2 and the monosialotetrahexosylganglioside (GM1). Previously, we showed that the TRAF domain occurs mainly in a trimeric form in solution, but it can also exist as a stable monomer when in the nanomolar concentration range. Here, we report that the quaternary structure of the TRAF domain is also affected by pH changes, since a weakly acidic pH (5.5) favors the dissociation of the trimeric TRAF domain into stable monomers, as previously observed at neutral pH (7.6) with the diluted protein. The TRAF domain-GM1 binding was similar at pH 5.5 and 7.6, suggesting that GM1 interacts with both the trimeric and monomeric forms of the protein. However, only the monomeric protein appeared to cause membrane deformation and inward vesiculation in GM1-containing giant unilamellar vesicles (GUVs). The formation of complexes between GM1 and TRAF2, or its TRAF domain, was also observed in cultured human leukemic HAP1 cells expressing either the truncated TRAF domain or the endogenous full length TRAF2. The GM1-protein complexes were observed after treatment with tunicamycin and were more concentrated in cells undergoing apoptosis, a condition which is known to cause cytoplasm acidification. These findings open the avenue for future studies aimed at deciphering the physiopathological relevance of the TRAF domain-GM1 interaction.

Silencing of CPNE1-TRAF2 Axis Restrains the Development of Pancreatic Cancer.

BACKGROUND: Copine 1 (CPNE1) acts as a promoter in the progression of many kinds of cancers with the exception of pancreatic cancer (PC). This research is designed to probe the function of the CPNE1-tumor necrosis factor receptor-associated factor 2 (TRAF2) axis in PC. METHODS: In vivo and in vitro models of PC were constructed, and a series of biological function tests, including MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide], colony formation, flow cytometry, and immunohistochemistry, were performed. RESULTS: The level of CPNE1 elevated dramatically in PC cells. Downregulation of CPNE1in PC cells resulted in the inhibition of colony formation and proliferation. In addition, the silencing of CPNE1 induced the G1/S arrest and apoptosis in PC cells. Additionally, TRAF2 positively interacted with CPNE1 in PANC cells. CPNE1 silencing also inhibited the growth of tumors in in vivo mouse models. Functional experiments revealed that the anti-tumor effect of CPNE1 silencing was counteracted by TRAF2 overexpression, and the tumor-promoting effect of TRAF2 overexpression was reversed by CPNE1 silencing. CONCLUSIONS: In summary, our findings indicate that the silencing of the CPNE1-TRAF2 axis restrains PC development.

The natural compound Sanggenon C inhibits PRRSV infection by regulating the TRAF2/NF-κB signalling pathway.

Porcine reproductive and respiratory syndrome (PRRS) is a serious infectious disease and one of the major causes of death in the global pig industry. PRRS virus (PRRSV) strains have complex and diverse genetic characteristics and cross-protection between strains is low, which complicates vaccine selection; thus, the current vaccination strategy has been greatly compromised. Therefore, it is necessary to identify effective natural compounds for the clinical treatment of PRRS. A small molecule library composed of 720 natural compounds was screened in vitro, and we found that Sanggenon C (SC) was amongst the most effective natural compound inhibitors of PRRSV infection. Compared with ribavirin, SC more significantly inhibited PRRSV infection at both the gene and protein levels and reduced the viral titres and levels of protein expression and inflammatory cytokine secretion to more effectively protect cells from PRRSV infection and damage. Mechanistically, SC inhibits activation of the NF-κB signalling pathway by promoting TRAF2 expression, thereby reducing PRRSV replication. In conclusion, by screening natural compounds, we found that SC suppresses PRRSV infection by regulating the TRAF2/NF-κB signalling pathway. This study contributes to a deeper understanding of the therapeutic targets and pathogenesis of PRRSV infection. More importantly, our results demonstrate that SC has potential as a candidate for the treatment of PRRS.

Erythropoietin inhibits neutrophil extracellular traps formation to ameliorate lung injury in a pneumonia model.

BACKGROUND: Severe pneumonia is a kind of disease that develops from lung inflammation, and new drugs are still required to treat the same. Erythropoietin (EPO) is widely used to treat anemia in patients. However, there are fewer studies on the role of EPO in neutrophil extracellular trappings (NETs) and pneumonia, and the mechanism is unclear. OBJECTIVE: To investigate the possible effects of EPO on the formation of NETs and progression of pneumonia. METHODS: Mice pneumonia model was induced by tracheal lipopolysaccharide (LPS) administration. Hematoxylin and eosin (H&E) staining and automatic blood cell analysis were performed in this model to confirm the effects of EPO on lung injury. Flow cytometry, enzyme-linked immunosorbent serological assay, and immunostaining assay were conducted to detect the effects of EPO on the inflammation as well as formation of NETs in mice. Immunoblot was further conducted to confirm the mechanism. RESULTS: EPO alleviated LPS-induced lung injury. EPO reduced the release of inflammatory factors induced by LPS. In addition, EPO inhibited the formation of NETs. Mechanically, EPO inhibited tumor necrosis factor (TNF) receptor associated factor 2 (TRAF2)/nuclear factor kappa-B (NF-κB) activity in mouse models, and therefore suppressed the progression of pneumonia. CONCLUSION: EPO inhibited formation of NETs to ameliorate lung injury in a pneumonia model, and could serve as a drug of pneumonia.

Fn14 and TNFR2 as regulators of cytotoxic TNFR1 signaling.

Tumor necrosis factor (TNF) receptor 1 (TNFR1), TNFR2 and fibroblast growth factor-inducible 14 (Fn14) belong to the TNF receptor superfamily (TNFRSF). From a structural point of view, TNFR1 is a prototypic death domain (DD)-containing receptor. In contrast to other prominent death receptors, such as CD95/Fas and the two TRAIL death receptors DR4 and DR5, however, liganded TNFR1 does not instruct the formation of a plasma membrane-associated death inducing signaling complex converting procaspase-8 into highly active mature heterotetrameric caspase-8 molecules. Instead, liganded TNFR1 recruits the DD-containing cytoplasmic signaling proteins TRADD and RIPK1 and empowers these proteins to trigger cell death signaling by cytosolic complexes after their release from the TNFR1 signaling complex. The activity and quality (apoptosis versus necroptosis) of TNF-induced cell death signaling is controlled by caspase-8, the caspase-8 regulatory FLIP proteins, TRAF2, RIPK1 and the RIPK1-ubiquitinating E3 ligases cIAP1 and cIAP2. TNFR2 and Fn14 efficiently recruit TRAF2 along with the TRAF2 binding partners cIAP1 and cIAP2 and can thereby limit the availability of these molecules for other TRAF2/cIAP1/2-utilizing proteins including TNFR1. Accordingly, at the cellular level engagement of TNFR2 or Fn14 inhibits TNFR1-induced RIPK1-mediated effects reaching from activation of the classical NFκB pathway to induction of apoptosis and necroptosis. In this review, we summarize the effects of TNFR2- and Fn14-mediated depletion of TRAF2 and the cIAP1/2 on TNFR1 signaling at the molecular level and discuss the consequences this has in vivo.

TRAF2 promotes M2-polarized tumor-associated macrophage infiltration, angiogenesis and cancer progression by inhibiting autophagy in clear cell renal cell carcinoma.

BACKGROUND: The management of advanced clear cell renal cell carcinoma (ccRCC) remains a major challenge in clinical practice, and the construction of more reliable prognostic prediction models and the further elucidation of key molecular mechanisms of tumor progression are topics in urgent need of in-depth investigation. METHODS: We used CIBERSORT to estimate the proportion of 22 tumor-infiltrating immune cell types in the TCGA-KIRC cohort. Weighted gene co-expression network analysis, least absolute shrinkage and selection operator regression analysis were used to build risk prediction models. Expression patterns and clinical significance of TRAF2 were determined through bioinformatics analysis, real-time qPCR, Western Blot, immunohistochemistry. GSEA analysis, transmission electron microscopy, 2D/3D colony formation assay, cell migration and invasion assay, and tube-formation assay were used to investigate the underlying function and mechanism of the TRAF2/M2 macrophage/autophagy axis. RESULTS: We constructed a novel prognostic prediction model based on M2 macrophage-related genes, which was identified as an accurate, independent and specific prognostic risk model for ccRCC patients. A reliable nomogram was constructed to predict 1-, 3-, and 5-year overall survival for patients with ccRCC. As one of the constituent genes of the risk model, TRAF2 was determined to be upregulated in ccRCC and associated with poor clinical prognosis. We found that TRAF2 promotes malignant progression of ccRCC by regulating macrophage polarization, migration and angiogenesis. Mechanistically, we found that TRAF2 promotes the polarization of M2 macrophages, and this chemotaxis is achieved in an autophagy-dependent pathway. Orthotopic tumor growth assay results revealed that TRAF2 plays a key role as a promotor of ccRCC growth and metastasis. CONCLUSIONS: In conclusion, this risk model is highly predictive of prognostic in ccRCC patients, which is expected to promote improved treatment evaluation and comprehensive management of ccRCC. Moreover, our findings reveal that the TRAF2/M2 macrophage/autophagy axis plays a key regulatory role in the malignant progression of ccRCC, and suggest that TRAF2 is a potential novel therapeutic target for advanced ccRCC.