Sheep (Ovis aries) Milk Exosomal miRNAs Attenuate Dextran Sulfate Sodium-Induced Colitis in Mice via TLR4 and TRAF-1 Inhibition.

Mammalian milk exosomal miRNAs play an important role in maintaining intestinal immune homeostasis and protecting epithelial barrier function, but the specific miRNAs and whether miRNA-mediated mechanisms are responsible for these benefits remain a matter of investigation. This study isolated sheep milk-derived exosomes (sheep MDEs), identifying the enriched miRNAs in sheep MDEs, oar-miR-148a, and oar-let-7b as key components targeting TLR4 and TRAF1, which was validated by a dual-luciferase reporter assay. In dextran sulfate sodium-induced colitis mice, administration of sheep MDEs alleviated colitis symptoms, reduced colonic inflammation, and systemic oxidative stress, as well as significantly increased colonic oar-miR-148a and oar-let-7b while reducing toll-like receptor 4 (TLR4) and TNF-receptor-associated factor 1 (TRAF1) level. Further characterization in TNF-α-challenged Caco-2 cells showed that overexpression of these miRNAs suppressed the TLR4/TRAF1-IκBα-p65 pathway and reduced IL-6 and IL-12 production. These findings indicate that sheep MDEs exert gastrointestinal anti-inflammatory effects through the miRNA-mediated modulation of TLR4 and TRAF1, highlighting their potential in managing colitis.

Role of Selected Genetic Polymorphisms in the Development of Rheumatoid Arthritis in a British White Population.

BACKGROUND: Rheumatoid arthritis (RA) is a complex autoimmune disease that negatively affects synovial joints, leading to the deterioration of movement and mobility of patients. This chronic disease is considered to have a strong genetic inheritance, with genome-wide association studies (GWAS) highlighting many genetic loci associated with the disease. Moreover, numerous confounding and non-genetic factors also contribute to the risk of the disease. AIMS: This study investigates the association of selected genetic polymorphisms with rheumatoid arthritis risk and develops a polygenic risk score (PRS) based on selected genes. METHODS: A case-control study recruited fully consenting participants from the East Midlands region of the UK. DNA samples were genotyped for a range of polymorphisms and genetic associations were calculated under several inheritance models. PRS was calculated at crude (unweighted) and weighted levels, and its associations with clinical parameters were determined. RESULTS: There were significant associations with the risk of RA at six genetic markers and their associated risk alleles (TNRF2*G, TRAF1*A, PTPN22*T, HLA-DRB1*G, TNFα*A, and IL4-590*T). The TTG haplotype at the VDR locus increased the risk of RA with an OR of 3.05 (CI 1.33-6.98, p = 0.009). The GA haplotype of HLADRB1-TNFα-308 was a significant contributor to the risk of RA in this population (OR = 2.77, CI 1.23-6.28, p = 0.01), although linkage disequilibrium was low. The polygenic risk score was significantly higher in cases over controls in both unweighted (mean difference = 1.48, t285 = 5.387, p < 0.001) and weighted (mean difference = 2.75, t285 = 6.437, p < 0.001) results. CONCLUSION: Several genetic loci contribute to the increased risk of RA in the British White sample. The PRS is significantly higher in those with RA and can be used for clinical applications and personalised prevention of disease.

The methyltransferase METTL3 regulates endothelial cell proliferation and inflammation via m6A RNA methylation-mediated TRAF1 expression.

The imbalance of vascular endothelial cell homeostasis is the key mechanism for the progression of many vascular diseases. RNA modification, particularly N6-Methyladenosine (m6A), plays important function in numerous biological processes. Nevertheless, the regulatory function of m6A RNA methylation in endothelial dysfunction remains insufficiently characterized. In this study, we established that the m6A methyltransferase METTL3 is critical for regulating endothelial function. Functionally, depletion of METTL3 results in decreased endothelial cells proliferation, survival and inflammatory response. Conversely, overexpression of METTL3 elicited the opposite effects. Mechanistically, MeRIP-seq identified that METTL3 catalyzed m6A modification of TRAF1 mRNA and enhanced TRAF1 translation, thereby up-regulation of TRAF1 protein. Over-expression of TRAF1 successfully rescued the inhibition of proliferation and adhesion of endothelial cells due to METTL3 knockdown. Additionally, m6A methylation-mediated TRAF1 expression can be reversed by the demethylase ALKBH5. Knockdown of ALKBH5 upregulated the level of m6A and protein level of TRAF1, and also increased endothelial cells adhesion and inflammatory response. Collectively, our findings suggest that METTL3 regulates vascular endothelium homeostasis through TRAF1 m6A modification, suggesting that targeting the METTL3-m6A-TRAF1 axis may hold therapeutic potential for patients with vascular diseases.

TRAF1 Deficiency in Macrophages Drives Exacerbated Joint Inflammation in Rheumatoid Arthritis.

The tumor necrosis factor receptor-associated factor 1 (TRAF1) plays a key role in promoting lymphocyte survival, proliferation, and cytokine production. Recent evidence showed that TRAF1 plays opposing roles in monocytes and macrophages where it controls NF-κB activation and limits pro-inflammatory cytokine production as well as inflammasome-dependent IL-1ß secretion. Importantly, TRAF1 polymorphisms have been strongly linked to an increased risk of rheumatoid arthritis (RA). However, whether and how TRAF1 contributes to RA pathogenesis is not fully understood. Moreover, investigating the role of TRAF1 in driving RA pathogenesis is complicated by its multifaceted and opposing roles in various immune cells. In this study, we subjected wildtype (WT) mice to the collagen antibody-induced arthritis (CAIA) model of RA and injected them intra-articularly with WT- or TRAF1-deficient macrophages. We show that mice injected with TRAF1-deficient macrophages exhibited significantly exacerbated joint inflammation, immune cell infiltration, and tissue damage compared to mice injected with WT macrophages. This study may lay the groundwork for novel therapies for RA that target TRAF1 in macrophages.

PKMYT1 knockdown inhibits cholesterol biosynthesis and promotes the drug sensitivity of triple-negative breast cancer cells to atorvastatin.

Triple negative breast cancer (TNBC) as the most aggressive molecular subtype of breast cancer is characterized by high cancer cell proliferation and poor patient prognosis. Abnormal lipid metabolism contributes to the malignant process of cancers. Study observed significantly enhanced cholesterol biosynthesis in TNBC. However, the mechanisms underlying the abnormal increase of cholesterol biosynthesis in TNBC are still unclear. Hence, we identified a member of the serine/threonine protein kinase family PKMYT1 as a key driver of cholesterol synthesis in TNBC cells. Aberrantly high-expressed PKMYT1 in TNBC was indicative of unfavorable prognostic outcomes. In addition, PKMYT1 promoted sterol regulatory element-binding protein 2 (SREBP2)-mediated expression of enzymes related to cholesterol biosynthesis through activating the TNF/ TNF receptor-associated factor 1 (TRAF1)/AKT pathway. Notably, downregulation of PKMYT1 significantly inhibited the feedback upregulation of statin-mediated cholesterol biosynthesis, whereas knockdown of PKMYT1 promoted the drug sensitivity of atorvastatin in TNBC cells. Overall, our study revealed a novel function of PKMYT1 in TNBC cholesterol biosynthesis, providing a new target for targeting tumor metabolic reprogramming in the cancer.

Uncovering the Interaction between TRAF1 and MAVS in the RIG-I Pathway to Enhance the Upregulation of IRF1/ISG15 during Classical Swine Fever Virus Infection.

Classical swine fever (CSF) is caused by the classical swine fever virus (CSFV), which poses a threat to swine production. The activation of host innate immunity through linker proteins such as tumor necrosis factor receptor (TNF-R)-associated factor (TRAF) is crucial for the induction of the NF-κB pathway. Recent research has revealed the involvement of mitochondrial antiviral-signaling protein (MAVS) in the interaction with TRAF2, 3, 5, and 6 to activate both the NF-κB and IRF3 pathways. This study revealed that CSFV infection led to the upregulation of TRAF1 mRNA and protein levels; moreover, TRAF1 overexpression inhibited CSFV replication, while TRAF1 knockdown promoted replication, highlighting its importance in the host response to CSFV infection. Additionally, the expression of RIG-I, MAVS, TRAF1, IRF1, and ISG15 were detected in PK-15 cells infected with CSFV, revealing that TRAF1 plays a role in regulating IRF1 and ISG15 within the RIG-I pathway. Furthermore, Co-IP, GST pull-down, and IFA analyses demonstrated that TRAF1 interacted with MAVS and co-localized in the cytoplasm during CSFV infection. Ultimately, TRAF1 acted as a novel member of the TRAF family, bound to MAVS as a linker molecule, and functioned as a mediator downstream of MAVS in the RIG-I/MAVS pathway against CSFV replication.

TRAF1 from a Structural Perspective.

Tumor necrosis factor receptor-associated factor (TRAF) proteins play pivotal roles in a multitude of cellular signaling pathways, encompassing immune response, cell fate determination, development, and thrombosis. Their involvement in these processes hinges largely on their ability to interact directly with diverse receptors via the TRAF domain. Given the limited binding interface, understanding how specific TRAF domains engage with various receptors and how structurally similar binding interfaces of TRAF family members adapt their distinct binding partners has been the subject of extensive structural investigations over several decades. This review presents an in-depth exploration of the current insights into the structural and molecular diversity exhibited by the TRAF domain and TRAF-binding motifs across a range of receptors, with a specific focus on TRAF1.

Interactions between TNFAIP3, PTPN22, and TRAF1-C5 gene polymorphisms in patients with primary Sjögren's syndrome.

Objectives: The aim of our study was to investigate whether TNFAIP3, PTPN22, and TRAF1-5 single nucleotide polymorphisms (SNPs) are associated with susceptibility, severity, or serological markers in primary Sjögren's syndrome (pSS). Patients and methods: The cases and controls study was conducted between December 2021 and June 2022. TNFAIP3 rs10499194C/T, rs6920220G/A, and rs2230926T/G, PTPN22 rs2476601C/T and rs33996649G/A, and TRAF1-C5 rs10818488G/A polymorphisms were genotyped in 154 female pSS patients (mean age: 45.2±6.8 years) and 313 female control subjects (mean age: 50.3±7.5 years) using the TaqMan® SNP genotyping assay. An association analysis between TNFAIP3, PTPN22, and TRAF1-C5 SNPs and susceptibility, clinical characteristics, and serological markers of pSS was performed. Interactions between TNFAIP3, PTPN22, and TRAF1-C5 SNPs were also evaluated in patients and controls. Results: The genotype and allele frequencies showed no association with susceptibility, severity, or serological markers of pSS. Nevertheless, several interactions between TNFAIP3 and TRAF1-C5 or TNFAIP3, PTPN22, and TRAF1-C5 genotypes were associated with susceptibility to pSS (p<0.01). Conclusion: Individual TNFAIP3, PTPN22, and TRAF1-C5 SNPs are not associated with susceptibility, severity, or serological markers of pSS. However, genetic interactions between TRAF1-C5 and TNFAIP3 or TNFAIP3, PTPN22, and TRAF1-C5 SNPs are risk factors for pSS.

Detection of TRAF1-ALK fusion in skin lesions of systemic ALK+ anaplastic large cell lymphoma initially involving the skin and the draining lymph node.

A case of cytoplasmic anaplastic lymphoma kinase (ALK)-positive anaplastic large cell lymphoma (ALCL) initially involving the skin in a 44-year-old Japanese female is reported. The patient had a hemorrhagic erythematous tumor on the right thigh without any systemic symptoms. Pathology showed diffuse infiltration of CD30-positive anaplastic large cells positive for epithelial membrane antigen and cytoplasmic ALK. The right inguinal lymph node showed infiltration of tumor cells in the marginal sinus. Only 2 weeks after radiation therapy, the patient developed multiple subcutaneous nodules and lung involvement. Even after subsequent multichemotherapy sessions, cutaneous recurrence occurred. Literature review of cytoplasmic ALK-positive ALCL initially involving in the skin revealed that skin lesions were mostly seen in the extremities and that half of the cases developed extracutaneous lesions. Radiation and chemotherapy were effective for most cases. Inverse RT-PCR identified a tumor necrosis factor receptor-associated factor (TRAF)1-ALK fusion in our case. Most reported cases with this translocation experienced repeated changes in chemotherapy, suggesting poorer prognosis. Although ALK-positive ALCL generally responds well to chemotherapy, the presence of a TRAF1-ALK fusion may suggest resistance to treatment. Detection of fusion partners of ALK is important for predicting clinical courses and deciding treatment options.

Association between TRAF1/C5 Gene Polymorphisms and IgA Vasculitis in Chinese Children.

OBJECTIVE: To investigate the association between loci rs3761847 and rs10818488 of tumor necrosis factor receptor-associated factor 1/complement C5 (TRAF1/C5) gene and the susceptibility to IgAV. METHODS: 100 blood samples of children with IgAV and 100 blood samples of healthy children were collected from the Third Xiangya Hospital of Central South University from June 2017 to June 2019. The target gene fragment was amplified by polymerase chain reaction (PCR), and the single nucleic acid gene polymorphism of the gene loci was detected by PCR sequencing based typing technique. The association between gene polymorphism of each locus and susceptibility to IgAV was analyzed. RESULTS: There were significant differences in both genotype (P < .05) and allele frequencies （P < .05) of rs3761847 of TRAF1/C5 gene between the IgAV group and the control group.Besides, the risks of developing IgAV in children with the TT genotype was 0.495 times and in children with the C allele was 1.627 times of that in children with other genotypes and alleles, respectively (P < .05). For IgAV patients, renal involvement risk in children with CC genotype was 5.859 times of that in children with other genotypes (P < .05). There were no significant differences in genotype (P > .05) and allele frequencies (P > .05) of rs10818488 of TRAF1/C5 gene between the IgAV group and the control group. IgAV patients with TT genotype had a 3.2 times higher risk of renal involvement than those with other genotypes (P < .05). CONCLUSIONS: There is an association between locus rs3761847 of TRAF1/C5 gene single nucleotide polymorphisms and susceptibility to IgAV. The T allele at locus rs3761847 of TRAF1/C5 gene may be a protective factor for IgAV. The C allele at locus rs3761847 and the T allele at locus rs10818488 of TRAF1/C5 gene may be associated with kidney injury in IgAV.

Identification of a regulatory pathway governing TRAF1 via an arthritis-associated non-coding variant.

TRAF1/C5 was among the first loci shown to confer risk for inflammatory arthritis in the absence of an associated coding variant, but its genetic mechanism remains undefined. Using Immunochip data from 3,939 patients with juvenile idiopathic arthritis (JIA) and 14,412 control individuals, we identified 132 plausible common non-coding variants, reduced serially by single-nucleotide polymorphism sequencing (SNP-seq), electrophoretic mobility shift, and luciferase studies to the single variant rs7034653 in the third intron of TRAF1. Genetically manipulated experimental cells and primary monocytes from genotyped donors establish that the risk G allele reduces binding of Fos-related antigen 2 (FRA2), encoded by FOSL2, resulting in reduced TRAF1 expression and enhanced tumor necrosis factor (TNF) production. Conditioning on this JIA variant eliminated attributable risk for rheumatoid arthritis, implicating a mechanism shared across the arthritis spectrum. These findings reveal that rs7034653, FRA2, and TRAF1 mediate a pathway through which a non-coding functional variant drives risk of inflammatory arthritis in children and adults.

TRAF1 improves cisplatin-induced acute kidney injury via inhibition of inflammation and metabolic disorders.

BACKGROUND: Cisplatin-induced acute kidney injury (AKI) is a severe clinical complication with no satisfactory therapies in the clinic. Tumor necrosis factor receptor (TNFR)-associated factor 1 (TRAF1) plays a vital role in both inflammation and metabolism. However, the TRAF1 effect in cisplatin induced AKI needs to be evaluated. METHODS: We observed the role of TRAF1 in eight-week-old male mice and mouse proximal tubular cells both treated with cisplatin by examining the indicators associated with kidney injury, apoptosis, inflammation, and metabolism. RESULTS: TRAF1 expression was decreased in cisplatin-treated mice and mouse proximal tubular cells (mPTCs), suggesting a potential role of TRAF1 in cisplatin-associated kidney injury. TRAF1 overexpression significantly alleviated cisplatin-triggered AKI and renal tubular injury, as demonstrated by reduced serum creatinine (Scr) and urea nitrogen (BUN) levels, as well as the ameliorated histological damage and inhibited upregulation of NGAL and KIM-1. Moreover, the NF-κB activation and inflammatory cytokine production enhanced by cisplatin were significantly blunted by TRAF1. Meanwhile, the increased number of apoptotic cells and enhanced expression of BAX and cleaved Caspase-3 were markedly decreased by TRAF1 overexpression both in vivo and vitro. Additionally, a significant correction of the metabolic disturbance, including perturbations in energy generation and lipid and amino acid metabolism, was observed in the cisplatin-treated mice kidneys. CONCLUSION: TRAF1 overexpression obviously attenuated cisplatin-induced nephrotoxicity, possibly by correcting the impaired metabolism, inhibiting inflammation, and blocking apoptosis in renal tubular cells. GENERAL SIGNIFICANCE: These observations emphasize the novel mechanisms associated to metabolism and inflammation of TRAF1 in cisplatin-induced kidney injury.

Knockdown of circ_0038467 alleviates lipopolysaccharides-induced 16HBE cell injury by regulating the miR-545-3p/TRAF1 axis in neonatal pneumonia.

BACKGROUND: Neonatal pneumonia is a common illness in the neonatal period with a high fatality rate. Accumulating proofs have attested to the crucial role of circular RNAs (circRNAs) in pneumonia. This study was intended to expound on the function of circ_0038467 and the underlying mechanism in lipopolysaccharide (LPS)-stimulated 16HBE cell injury in neonatal pneumonia. METHODS: 16HBE cells were exposed to LPS to establish an in vitro neonatal pneumonia cell model. Quantitative real-time polymerase chain reaction (qRT-PCR) was implemented for detecting the levels of circ_0038467, microRNA-545-3p (miR-545-3p), and tumor necrosis factor receptor-associated factor 1 (TRAF1) in neonatal pneumonia serums and LPS-treated 16HBE cells. Cell Counting Kit-8 (CCK-8), 5-ethynyl-2'-deoxyuridine (EdU) incorporation, and flow cytometry assays were used to examine cell viability, proliferation, and apoptosis, respectively. The protein abundances of proliferation/apoptosis/inflammation-correlated makers and TRAF1 were tested by Western blot. RNase R and Actinomycin D assays were implemented to determine the features of circ_0038467. The mutual effect between miR-545-3p and circ_0038467 or TRAF1 was affirmed by a dual-luciferase reporter and RNA pull-down assay assays. RESULTS: Circ_0038467 was upregulated in neonatal pneumonia serum specimens and LPS-triggered 16HBE cells. LPS administration restrained 16HBE cell proliferation and promoted apoptosis and inflammation, whereas circ_0038467 silence recovered these influences. Meanwhile, miR-545-3p was targeted by circ_0038467, and circ_0038467 could modulate LPS-treated 16HBE cell injury through absorbing miR-545-3p. Furthermore, circ_0038467 controlled TRAF1 level via segregating miR-545-3p. Moreover, TRAF1 overexpression relieved the suppressive impact of circ_0038467 silence in LPS-triggered 16HBE cell detriment. CONCLUSION: Circ_0038467 knockdown mitigated LPS-exposed 16HBE cell damage through regulating miR-545-3p/PPARA axis.

CD40/TRAF1 decreases synovial cell apoptosis in patients with rheumatoid arthritis through JNK/NF-κB pathway.

INTRODUCTION: A genome-wide association analysis revealed a rheumatoid arthritis (RA)-risk-associated genetic locus on chromosome 9, which contained the tumor necrosis factor receptor-associated factor 1 (TRAF1). However, the detail mechanism by TRAF1 signaled to fibroblast-like synoviocytes (FLSs) apoptosis remains to be fully understood. MATERIALS AND METHODS: Synovial tissue of 10 RA patients and osteoarthritis patients were obtained during joint replacement surgery. We investigated TRAF1 level and FLSs apoptosis percentage in vivo and elucidated the mechanism involved in the regulation of apoptotic process in vitro. RESULTS: We proved the significant increase of TRAF1 level in FLSs of RA patients and demonstrated that TRAF1 level correlated positively with DAS28 score and negatively with FLSs apoptosis. Treatment with siTRAF1 was able to decrease MMPs levels and the phosphorylated forms of JNK/NF-κB in vitro. Moreover, JNK inhibitor could attenuate expression of MMPs and increase percentage of apoptosis in RA-FLSs, while siTRAF1 could not promote apoptosis when RA-FLSs were pretreated with JNK activator. CONCLUSIONS: High levels of TRAF1 in RA synovium play an important role in the synovial hyperplasia of RA by suppressing apoptosis through activating JNK/NF-kB-dependent signaling pathways in response to the engagement of CD40.

LINC00313 alleviates osteoarthritis progression in mice through promoting TRAF1 promoter methylation and inhibiting the ASK1/JNK signaling pathway.

OBJECTIVES: This study aimed to explore the underlying role and mechanism of LINC00313 in osteoarthritis (OA) progression. METHODS: CHON-001 chondrocytes were treated with interleukin (IL)-1ß to induce OA in vitro, and then transfected with LINC00313 overexpression plasmids (pcDNA-LINC00313) or small interfering RNA against tumor necrosis factor (TNF) receptor-associated factor 1 (si-TRAF1). Cell viability, apoptosis, levels of inflammatory cytokines tumor necrosis factor-α (TNF-α), IL-6 and IL-8, and expression of extracellular matrix (ECM) degradation related proteins in CHON-001 cells were determined. TRAF1 promoter methylation were was detected with methylation-specific polymerase chain reaction (MSP) assay. Furthermore, a c-Jun N-terminal kinase (JNK) signaling activator was used to confirm whether the apoptosis signal-regulating kinase 1 (ASK1)/JNK signaling pathway was involved in the function of LINC00313/TRAF1 axis in chondrocytes. In addition, an OA mouse model was established and lentivirus LINC00313 overexpression vector (Lv-LINC00313) was injected, and then inflammatory cytokine levels, ECM protein expression, and pathological changes in cartilage tissues were detected. RESULTS: LINC00313 was downregulated and TRAF1 was upregulated in OA cartilage tissues. LINC00313 overexpression or TRAF1 silencing attenuated IL-1ß-induced viability inhibition, apoptosis, inflammation and ECM degradation in CHON-001 cells. Moreover, LINC00313 inhibited TRAF1 expression through promoting DNA methyltransferase 1 (DNMT1) mediated promoter methylation. TRAF1 overexpression reversed the effects of LINC00313 on IL-1ß-induced chondrocyte injury. LINC00313 overexpression inhibited the ASK1/JNK signaling pathway, and JNK activator reversed the effect. In addition, Lv-LINC00313 treatment alleviated cartilage tissue damage and cartilage matrix degradation in OA mice. CONCLUSIONS: LINC00313 alleviated OA progression through inhibiting TRAF1 expression and the ASK1/JNK signaling pathway.

Tumor Necrosis Factor Receptor 2 (TNFR2): An Emerging Target in Cancer Therapy.

Despite the great success of TNF blockers in the treatment of autoimmune diseases and the identification of TNF as a factor that influences the development of tumors in many ways, the role of TNFR2 in tumor biology and its potential suitability as a therapeutic target in cancer therapy have long been underestimated. This has been fundamentally changed with the identification of TNFR2 as a regulatory T-cell (Treg)-stimulating factor and the general clinical breakthrough of immunotherapeutic approaches. However, considering TNFR2 as a sole immunosuppressive factor in the tumor microenvironment does not go far enough. TNFR2 can also co-stimulate CD8+ T-cells, sensitize some immune and tumor cells to the cytotoxic effects of TNFR1 and/or acts as an oncogene. In view of the wide range of cancer-associated TNFR2 activities, it is not surprising that both antagonists and agonists of TNFR2 are considered for tumor therapy and have indeed shown overwhelming anti-tumor activity in preclinical studies. Based on a brief summary of TNFR2 signaling and the immunoregulatory functions of TNFR2, we discuss here the main preclinical findings and insights gained with TNFR2 agonists and antagonists. In particular, we address the question of which TNFR2-associated molecular and cellular mechanisms underlie the observed anti-tumoral activities of TNFR2 agonists and antagonists.

N6-methyladenosine-modified TRAF1 promotes sunitinib resistance by regulating apoptosis and angiogenesis in a METTL14-dependent manner in renal cell carcinoma.

BACKGROUND: Sunitinib resistance can be classified into primary and secondary resistance. While accumulating research has indicated several underlying factors contributing to sunitinib resistance, the precise mechanisms in renal cell carcinoma are still unclear. METHODS: RNA sequencing and m6A sequencing were used to screen for functional genes involved in sunitinib resistance. In vitro and in vivo experiments were carried out and patient samples and clinical information were obtained for clinical analysis. RESULTS: We identified a tumor necrosis factor receptor-associated factor, TRAF1, that was significantly increased in sunitinib-resistant cells, resistant cell-derived xenograft (CDX-R) models and clinical patients with sunitinib resistance. Silencing TRAF1 increased sunitinib-induced apoptotic and antiangiogenic effects. Mechanistically, the upregulated level of TRAF1 in sunitinib-resistant cells was derived from increased TRAF1 RNA stability, which was caused by an increased level of N6-methyladenosine (m6A) in a METTL14-dependent manner. Moreover, in vivo adeno-associated virus 9 (AAV9) -mediated transduction of TRAF1 suppressed the sunitinib-induced apoptotic and antiangiogenic effects in the CDX models, whereas knockdown of TRAF1 effectively resensitized the sunitinib-resistant CDXs to sunitinib treatment. CONCLUSIONS: Overexpression of TRAF1 promotes sunitinib resistance by modulating apoptotic and angiogenic pathways in a METTL14-dependent manner. Targeting TRAF1 and its pathways may be a novel pharmaceutical intervention for sunitinib-treated patients.

DNMT1-induced miR-378a-3p silencing promotes angiogenesis via the NF-κB signaling pathway by targeting TRAF1 in hepatocellular carcinoma.

BACKGROUND: Angiogenesis plays an important role in the occurrence, development and metastasis of hepatocellular carcinoma (HCC). According to previous studies, miR-378a participates in tumorigenesis and tumor metastasis, but its exact role in HCC angiogenesis remains poorly understood. METHODS: qRT-PCR was used to investigate the expression of miR-378a-3p in HCC tissues and cell lines. The effects of miR-378a-3p on HCC in vitro and in vivo were examined by Cell Counting Kit-8 (CCK-8), Transwell, tube formation and Matrigel plug assays, RNA sequencing, bioinformatics, luciferase reporter, immunofluorescence and chromatin immunoprecipitation (ChIP) assays were used to detect the molecular mechanism by which miR-378a-3p inhibits angiogenesis. RESULTS: We confirmed that miR-378a-3p expression was significantly downregulated and associated with higher microvascular density (MVD) in HCC; miR-378a-3p downregulation indicated a short survival time in HCC patients. miR-378a-3p knockdown led to a significant increase in angiogenesis in vitro and in vivo. We found that miR-378a-3p directly targeted TNF receptor associated factor 1 (TRAF1) to attenuate NF-κB signaling, and then downregulated secreted vascular endothelial growth factor. DNA methyltransferase 1 (DNMT1)-mediated hypermethylation of miR-378a-3p was responsible for downregulating miR-378a-3p. Moreover, a series of investigations indicated that p65 initiated a positive feedback loop that could upregulate DNMT1 to promote hypermethylation of the miR-378a-3p promoter. CONCLUSION: Our study indicates a novel DNMT1/miR-378a-3p/TRAF1/NF-κB positive feedback loop in HCC cells, which may become a potential therapeutic target for HCC.

Blocking tumor necrosis factor-α delays progression of chronic obstructive pulmonary disease in rats through inhibiting MAPK signaling pathway and activating SOCS3/TRAF1.

The present study was conducted in order to study the detailed molecular mechanism of tumor necrosis factor (TNF)-α in chronic obstructive pulmonary disease (COPD). The rats were treated with cigarette smoke (CS) and lipopolysaccharide (LPS) to establish the COPD model. Next, the changes in lung injury in COPD rats with TNF-α knockdown was tested. Meanwhile, the regulation of TNF-α on MAPK pathway and its downstream molecules (SOCS3/TRAF1) was determined by western blotting. On this basis, the activation of MAPK and inhibition of SOCS3/TRAF1 was also examined. Subsequently, the lung function was tested with the plethysmograph, the cells of bronchoalveolar lavage fluid was counted and classified. Furthermore, lung tissue sections were stained with hematoxylin and eosin to verify whether the treatment of MAPK pathway and downstream molecules affected the effect of TNF-α knockdown on COPD. The present study showed that TNF-α knockdown could alleviate the decrease in the function and inflammatory injury of the lungs of rats with COPD. Western blot analysis verified that TNF-α knockdown could inhibit the activation of MAPK pathway and increase the expression of SOCS3/TRAF1. The following experimental results showed that the relief of lung injury caused by TNF-α knockdown could be deteriorated by activating MAPK pathway. It was also found that the symptom of COPD was decreased following transfection with sh-TNF-α but worsened by SOCS3/TRAF1 knockdown. Overall, TNF-α knockdown inhibited the activation of MAPK pathway and increased the expression of SOCS3/TRAF1, thus delaying the process of COPD.

A genetic variant in the TRAF1/C5 gene lead susceptibility to active pulmonary tuberculosis by decreased TNF-α levels.

Host genetics are important to consider in the role of resistance or susceptibility for developing active pulmonary tuberculosis (TB). Several association studies have reported the role of variants in STAT4 and TRAF1/C5 as risk factors to autoimmune diseases. Nevertheless, more data is needed to elucidate the role of these gene variants in infectious disease. Our data reports for the first time, variant rs10818488 in the TRAF1/C5 gene (found 47% of the population worldwide), is associated with susceptibility (OR = 1.51) to development TB. Multivariate analysis evidenced association between rs10818488 TRAF1/C5 and risk to multibacillary TB (OR = 4.18), confers increased bacteria load in the lung, indicates a decreased ability to control pathogen levels in the lung, and spread of the pathogen to new hosts. We showed that the "loss-of-function" variant in TRAF1/C5 led to susceptibility for TB by decreased production of TNF-α. Our results suggest the role of variant TRAF1/C5 in susceptibility to TB as well as in clinical presentation of multibacillary TB.