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.

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.

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.

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.

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.

TRAF1 suppresses antifungal immunity through CXCL1-mediated neutrophil recruitment during Candida albicans intradermal infection.

BACKGROUND: Candida albicans is the most common opportunistic human fungal pathogen. The chemokine ligand CXCL1 plays a protective role in fungal infection through the recruitment of neutrophils. TRAF1 (tumor necrosis factor-associated factor 1) can be highly induced by proinflammatory stimuli such as LPS and TNF and has been implicated in septic shock. However, the role of TRAF1 in infection, especially fungal infection, remains elusive. Herein, we reveal that TRAF1 suppresses the antifungal immune response to Candida albicans intradermal infection through the regulation of CXCL1 induction and neutrophil recruitment. METHODS: A mouse model of C. albicans intradermal infection was established. The Traf1-/- mice and Traf1-/- immortalized human keratinocytes were generated. The p65 inhibitor triptolide, STAT1 inhibitor fludarabine, neutrophil-depletion antibody Ly6G, and neutralizing antibody for CXCL1 were utilized. The expression of proinflammatory cytokines and chemokines was assessed by real-time PCR and ELISA, and the activation of signaling molecules was analyzed by Western blotting. Hematoxylin and eosin staining and periodic acid Schiff staining were used for histology or fungal detection, respectively. The immunofluorescence and flow cytometry analyses were employed in the assessment of immune cell infiltration. Bone marrow transplantation and adoptive transfer experiments were conducted to establish a role for TRAF1 in the macrophage compartment in fungal skin infection. RESULTS: TRAF1-deficient mice demonstrated improved control of Candida albicans intradermal infection, and concomitant increase in neutrophil recruitment and reduction in fungal burden. The chemokine CXCL1 was upregulated in the TRAF1-deficient macrophages treated with heat-killed C. albicans. Mechanistically, TRAF1-deficient macrophages showed increased activation of transcription factor NFκB p65. The human CXCL8 was also highly induced in the TRAF1-deficient human keratinocytes upon TNF stimulation through decreasing the activation of transcription factor STAT1. TRAF1-deficient macrophages played a critical role in containing the C. albicans skin infection in vivo. CONCLUSION: TRAF1-deficient mice can better control fungal infection in the skin, a process attributable to the CXCL-neutrophil axis. Mechanistically, TRAF1 likely regulates CXCL1 expression in both macrophages and keratinocytes through the transcriptional factor NFκB and STAT1, respectively. Our finding offers new insight into the understanding of the immune regulatory mechanisms in host defense against C. albicans infection.

Association of TRAF1/C5 Locus Polymorphisms with Epilepsy and Clinical Traits in Mexican Patients with Neurocysticercosis.

Neurocysticercosis is caused by the establishment of Taenia solium cysts in the central nervous system. Murine cysticercosis by Taenia crassiceps is a useful model of cysticercosis in which the complement component 5 (C5) has been linked to infection resistance/permissiveness. This work aimed to study the possible relevance for human neurocysticercosis of single nucleotide polymorphisms (SNPs) in the C5-TRAF1 region (rs17611 C/T, rs992670 G/A, rs25681 G/A, rs10818488 A/G, and rs3761847 G/A) in a Mexican population and associated with clinical and radiological traits related to neurocysticercosis severity (cell count in the cerebrospinal fluid [CSF cellularity], parasite location and parasite load in the brain, parasite degenerating stage, and epilepsy). The AG genotype of the rs3761847 SNP showed a tendency to associate with multiple brain parasites, while the CT and GG genotypes of the rs17611 and rs3761847 SNPs, respectively, showed a tendency to associate with low CSF cellularity. The rs3761847 SNP was associated with epilepsy under a dominant model, whereas rs10818488 was associated with CSF cellularity and parasite load under dominant and recessive models, respectively. For haplotypes, C5- and the TRAF1-associated SNPs were, respectively, in strong linkage disequilibrium with each other; thus, these haplotypes were studied independently. For C5 SNPs, carrying the CAA haplotype increases the risk of showing high CSF cellularity 3-fold and the risk of having extraparenchymal parasites 4-fold, two conditions that are related to severe disease. For TRAF1 SNPs, the GA and AG haplotypes were associated with CSF cellularity, and the AG haplotype was associated with epilepsy. Overall, these findings support the clear participation of C5 and TRAF1 in the risk of developing severe neurocysticercosis in the Mexican population.

TRAF1 meditates lipopolysaccharide-induced acute lung injury by up regulating JNK activation.

Acute lung injury (ALI) is served as a severe life-threatening disease. However, the pathogenesis that contributes to ALI has not been fully understood. Tumor necrosis factor receptor-associated factor 1 (TRAF1) interacts with multiple regulators, performing its diverse role in biological functions. However, the effects of TRAF1 on ALI remain unknown. In this study, we attempted to explore the role of TRAF1 in ALI progression. The findings suggested that TRAF1-knockout (KO) markedly attenuated LPS-induced severe mortality rate in murine animals. LPS-elicited histological alterations in pulmonary tissues were significantly alleviated by TRAF1-deletion. Additionally, TRAF1 knockout effectively attenuated lung injury, as evidenced by the reduced lung wet/dry (W/D) weight ratio, as well as decreased bronchoalveolar lavage fluid (BALF) protein levels and neutrophil infiltration. Meanwhile, TRAF1 deletion markedly lessened inflammation, oxidative stress and apoptosis in BALF and/or lung tissues. The levels of pro-inflammatory cytokines stimulated by LPS were down-regulated by TRAF1 ablation, along with the inactivation of nuclear factor κB (NF-κB). LPS-promoted reactive oxygen species (ROS) generation was decreased in TRAF1-KO mice, partly through the improvement of anti-oxidants. Apoptosis was also inhibited by TRAF1 deletion in lung tissues of LPS-challenged mice through the suppression of cleaved Caspase-3. Moreover, TRAF1 knockout significantly decreased c-Jun N-terminal kinase (JNK) activation and its down-streaming signal of c-Jun in pulmonary samples of LPS-induced mice. Importantly, the in vitro study suggested that promoting JNK activation markedly abrogated TRAF1 knockdown-attenuated inflammation, ROS production and apoptosis in LPS-exposed A549 cells. Therefore, our experimental results provided evidence that TRAF1 suppression effectively protected LPS-induced ALI against inflammation, oxidative stress and apoptosis through the suppression of JNK activity.

According to Hepatitis C Virus (HCV) Infection Stage, Interleukin-7 Plus 4-1BB Triggering Alone or Combined with PD-1 Blockade Increases TRAF1low HCV-Specific CD8+ Cell Reactivity.

Hepatitis C virus (HCV)-specific CD8+ T cells suffer a progressive exhaustion during persistent infection (PI) with HCV. This process could involve the positive immune checkpoint 4-1BB/4-1BBL through the loss of its signal transducer, TRAF1. To address this issue, peripheral HCV-specific CD8+ T cells (pentamer-positive [pentamer+]/CD8+ T cells) from patients with PI and resolved infection (RI) after treatment were studied. The duration of HCV infection and the liver fibrosis progression rate inversely correlated with the likelihood of detection of peripheral pentamer+/CD8+ cells. In PI, pentamer+/CD8+ cells had impaired antigen-specific reactivity that worsened when these cells were not detectable ex vivo Short/midduration PI was characterized by detectable peripheral PD-1+ CD127low TRAF1low cells. After triggering of T cell receptors (TCR), the TRAF1 level positively correlated with the levels of CD127, Mcl-1, and CD107a expression and proliferation intensity but negatively with PD-1 expression, linking TRAF1low to exhaustion. In vitro treatment with interleukin-7 (IL-7) upregulated TRAF1 expression, while treatment with transforming growth factor-ß1 (TGF-ß1) did the opposite, suggesting that the IL-7/TGF-ß1 balance, besides TCR stimulation, could be involved in TRAF1 regulation. In fact, the serum TGF-ß1 concentration was higher in patients with PI than in patients with RI, and it negatively correlated with TRAF1 expression. In line with IL-7 increasing the level of TRAF1 expression, IL-7 plus 4-1BBL treatment in vitro enhanced T cell reactivity in patients with short/midduration infection. However, in patients with long-lasting PI, anti-PD-L1, in addition to the combination of IL-7 and 4-1BBL, was necessary to reestablish T cell proliferation in individuals with slowly progressing liver fibrosis (slow fibrosers) but had no effect in rapid fibrosers. In conclusion, a peripheral hyporeactive TRAF1low HCV-specific CD8+ T cell response, restorable by IL-7 plus 4-1BBL treatment, characterizes short/midduration PI. In long-lasting disease, HCV-specific CD8+ T cells are rarely detectable ex vivo, but treatment with IL-7, 4-1BBL, and anti-PD-L1 recovers their reactivity in vitro in slow fibrosers.IMPORTANCE Hepatitis C virus (HCV) infects 71 million people worldwide. Two-thirds develop a chronic disease that can lead to cirrhosis and hepatocellular carcinoma. Direct-acting antivirals clear the infection, but there are still patients who relapse. In these cases, additional immunotherapy could play a vital role. A successful anti-HCV immune response depends on virus-specific CD8+ T cells. During chronic infection, these cells are functionally impaired, which could be due to the failure of costimulation. This study describes exhausted specific T cells, characterized by low levels of expression of the signal transducer TRAF1 of the positive costimulatory pathway 4-1BB/4-1BBL. IL-7 upregulated TRAF1 expression and improved T cell reactivity in patients with short/midduration disease, while in patients with long-lasting infection, it was also necessary to block the negative PD-1/PD-L1 checkpoint. When the results are taken together, this work supports novel ways of restoring the specific CD8+ T cell response, shedding light on the importance of TRAF1 signaling. This could be a promising target for future immunotherapy.

miR-214 Down-Regulation Promoted Hypoxia/Reoxygenation-Induced Hepatocyte Apoptosis Through TRAF1/ASK1/JNK Pathway.

OBJECTIVE: This study investigated the role of miR-214 in the hepatocyte apoptosis induced by hypoxia/reoxygenation (H/R) injury. MATERIALS AND METHODS: In vivo hepatic ischemia/reperfusion (HIR) injury, mice model and in vitro HR model were established. miR-214, TRAF1, ASK1, and JNK expression levels were detected by qRT-PCR and western blot. The apoptosis of mouse hepatocyte AML12 was detected by flow cytometry analysis. The interaction between miR-214 and TRAF1 was confirmed by dual-luciferase reporter gene assay. RESULTS: Serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels were elevated in HIR injury mice compared with sham mice. miR-214 expression was down-regulated in liver tissues of HIR and H/R-induced hepatocytes, whereas TRAF1, ASK1, and JNK expressions were up-regulated in HIR and H/R groups. H/R stimulation promoted the apoptosis of hepatocytes, and miR-214 overexpression inhibited the apoptosis of hepatocytes. Besides, TRAF1 was a target of miR-214 and negatively regulated by miR-214. miR-214/TRAF1 pathway involved in the modulation of H/R-induced apoptosis of hepatocytes. In vivo study proved miR-214 reduced hepatic injury of HIR mice. CONCLUSION: miR-214 overexpression reduces hepatocyte apoptosis after HIR injury through negatively regulating TRAF1/ASK1/JNK pathway.

[CD40/TNF receptor associated factor 1 expression and NF-κB-dependent proinflammatory gene expression in rheumatoid arthritis].

Objective: To investigatea cellular/molecular mechanism of the CD40/TRAF1 signalling pathway involved in Rheumatoid arthritis (RA). Methods: 16 patients with active RA and 9 patients with Fractures who underwent total knee or hip replacement in The First Affiliated Hospital of Soochow University were included in the study. Synovial tissues (ST) and serum were obtained from each patient. The CD40, TRAF1, NF-κB p65 were detected by ELISA and Immunohistochemistry in serum and tissue respectively. Real time-PCR (RT-PCR) was applied to measure NF-κB-related gene expression. Results: CD40 and TRAF1 positive area (%) in RA patients were 28.7±5.4, 34.3±4.8 respectively, which were significantly higher (P<0.05) than Fracture controls (21.2±9.5, 21.6±8.7 respectively). The expression of total NF-κB p65, and phospho-NF-κB p65 proteins, as well as NF-κB-related gene expression, including cytokines (TNFα, IL-6), chemokines (MCP-1),and adhesion molecules (ICAM-1) were significantly higher in the ST of RA patients compared to Fracture controls. Conclusion: It is thus possible that the CD40/TRAF1 pathway acted as a positive regulator through NF-κB activation and NF-κB-dependent proinflammatory genes in RA.

Associations of TRAF1/C5 rs10818488 and rs3761847 polymorphisms with genetic susceptibility to rheumatoid arthritis: a case-control study and updated meta-analysis.

The results on associations of tumor necrosis factor (TNF)-receptor associated factor 1/complement component 5 (TRAF1/C5) rs10818488 and rs3761847 polymorphisms with rheumatoid arthritis (RA) are controversial, thus this study was performed to examine whether the aforementioned polymorphisms were associated with RA in a Chinese population. Furthermore, an updated meta-analysis was conducted. The polymorphisms were genotyped in 328 Chinese RA patients and 449 healthy controls. Studies examining the association of TRAF1/C5 rs10818488 and/or rs3761847 polymorphism with RA were exhaustively searched. No significant difference in either genotype or allele distribution between RA patients and controls was found. The updated meta-analysis was conducted based on 19 articles including the present study. A significant association of RA with TRAF1/C5 rs10818488 polymorphism G allele in Europeans (OR = 0.843, 95% CI = 0.730-0.975, p = 0.021) and in Asians (OR = 1.070, 95% CI = 1.009-1.136, p = 0.024) was found. Additionally, a significant association of RA with TRAF1/C5 rs10818488 polymorphism G allele under the recessive model in Asians (OR = 1.129, 95% CI = 1.023-1.246, p = 0.016) and in Africans (OR = 0.657, 95% CI = 0.507-0.851, p = 0.001) was found. Only a borderline significant association of RA with TRAF1/C5 rs3761847 polymorphism A allele was found in Europeans. Non-significant associations of RA with TRAF1/C5 rs10818488 and rs3761847 polymorphisms were found in our study. The updated meta-analysis results demonstrate that TRAF1/C5 rs10818488 polymorphism is associated with RA in Europeans, Asians and Africans, and TRAF1/C5 rs3761847 polymorphism is associated with RA in Europeans with borderline significant evidence.

Targeting hepatic TRAF1-ASK1 signaling to improve inflammation, insulin resistance, and hepatic steatosis.

BACKGROUND & AIMS: Tumor necrosis factor receptor-associated factor 1 (TRAF1) is an important adapter protein that is largely implicated in molecular events regulating immunity/inflammation and cell death. Although inflammation is closely related to and forms a vicious circle with insulin dysfunction and hepatic lipid accumulation, the role of TRAF1 in hepatic steatosis and the related metabolic disorders remains unclear. METHODS: The participation of TRAF1 in the initiation and progression of hepatic steatosis was evaluated in high fat diet (HFD)-induced and genetic obesity. Mice with global TRAF1 knockout or liver-specific TRAF1 overexpression were employed to investigate the role of TRAF1 in insulin resistance, inflammation, and hepatic steatosis based on various phenotypic examinations. Molecular mechanisms underlying TRAF1-regulated hepatic steatosis were further explored in vivo and in vitro. RESULTS: TRAF1 expression was significantly upregulated in the livers of NAFLD patients and obese mice and in palmitate-treated hepatocytes. In response to HFD administration or in ob/ob mice, TRAF1 deficiency was hepatoprotective, whereas the overexpression of TRAF1 in hepatocytes contributed to the pathological development of insulin resistance, inflammatory response and hepatic steatosis. Mechanistically, hepatocyte TRAF1 promotes hepatic steatosis through enhancing the activation of ASK1-mediated P38/JNK cascades, as evidenced by the fact that ASK1 inhibition abolished the exacerbated effect of TRAF1 on insulin dysfunction, inflammation, and hepatic lipid accumulation. CONCLUSIONS: TRAF1 functions as a positive regulator of insulin resistance, inflammation, and hepatic steatosis dependent on the activation of ASK1-P38/JNK axis.

Genetic Modifiers of Patent Ductus Arteriosus in Term Infants.

OBJECTIVE: To identify single-nucleotide polymorphisms (SNPs) in specific candidate genes associated with patent ductus arteriosus in term infants. STUDY DESIGN: We conducted an initial family-based, candidate gene study to analyze genotype data from DNA samples obtained from 171 term infants and their parents enrolled in the National Birth Defects Prevention Study (NBDPS). We performed transmission disequilibrium testing (TDT) using a panel of 55 SNPs in 17 genes. Replication of SNPs with P < .1 in the NBDPS trios was performed with a case-control strategy in an independent population. RESULTS: TDT analysis of the NBDPS trios resulted in 6 SNPs reaching the predetermined cutoff (P < .1) to be included in the replication study. These 6 SNPs were genotyped in the independent case-control population. A SNP in TGFBR2 was found to be associated with term patent ductus arteriosus in both populations after we corrected for multiple comparisons. (rs934328, TDT P = 2 × 10(-4), case-control P = 6.6 × 10(-5)). CONCLUSIONS: These findings confirm the importance of the transforming growth factor-beta pathway in the closure of the term ductus arteriosus and may suggest new therapeutic targets.

The Upregulation of TRAF1 Induced by Helicobacter pylori Plays an Antiapoptotic Effect on the Infected Cells.

BACKGROUND: Tumor necrosis factor receptor-associated factor 1 (TRAF1) is a member of the TRAF family and is dysregulated in diseases, such as atheroma, lymphoma, and solid tumors, but the role of TRAF1 in gastric cancer remains unknown. This study was aimed to investigate the role of TRAF1 in Helicobacter pylori (H. pylori)-related cell apoptosis and gastric carcinogenesis. MATERIALS AND METHODS: The mRNA and protein expression levels of TRAF1 were measured in a panel of gastric cancer cell lines and in H. pylori -infected mice by quantitative real-time PCR (qPCR) and Western blotting. The transcription factor that mainly affects transcription of TRAF1 during H. pylori infection was identified. The roles of H. pylori virulence factors that regulate TRAF1 expression were analyzed using isogenic cagA-, vacA-, and cagE-null mutants. The effects of TRAF1 on gastric cell viability and apoptosis during H. pylori infection were detected using the standard MTS (cell viability) assay and flow cytometry, respectively. RESULTS: H. pylori infection induced TRAF1 overexpression in both gastric epithelial cells and mice. The expression of TRAF1 in response to H. pylori infection was majorly regulated by the activation of NF-κB and was strongly related to H. pylori virulence factor CagA. The upregulation of TRAF1 inhibited cell apoptosis and increased the viability of infected cells. CONCLUSIONS: H. pylori infection induces the overexpression of TRAF1 in gastric epithelial cells. The upregulation of TRAF1 plays an antiapoptotic role in H. pylori -infected gastric cells and may contribute to the gastric carcinogenesis.

Association of the polymorphisms of TRAF1 (rs10818488) and TNFAIP3 (rs2230926) with rheumatoid arthritis and systemic lupus erythematosus and their relationship to disease activity among Egyptian patients.

AIM OF THE STUDY: Recent studies demonstrated the association of tumor necrosis factor α-induced protein 3 (TNFAIP3) (rs2230926) and tumor necrosis factor receptor associated factor 1 (TRAF1) (rs10818488) with rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE) in different populations. We aimed at determining whether they confer susceptibility to SLE and RA in Egyptian population and if there is any relation to disease activity and auto-antibodies profile. MATERIAL AND METHODS: A case-control study involving 105 individuals with RA, 90 with SLE and 75 healthy controls was performed using TaqMan genotyping assay for two SNPs that showed the best evidence of association in the previous Caucasian studies. RESULTS: We detected significant differences in G allele frequency of TNFAIP3 (rs2230926) with SLE (p = 0.017(*)) and RA (OR = 2.333; 95% CI: 1.103-4.935, p = 0.023(*)) and association with RA disease activity (< 0.001). The A allele of TRAF1 was significantly increased in RA compared to controls(p = 0.049) and with RA activity (p = 0.001), while TRAF1 polymorphism did not exhibit any significant difference in the frequencies of genotypes or alleles in SLE and control (p = 0.280). CONCLUSIONS: TNFAIP3 is a susceptibility gene to SLE and RA in the Egyptian population and is correlated to disease activity and the presence of autoantibodies while TRAF1 polymorphisms increase the risk of RA but not to SLE in Egyptian populations.

TRAF1 knockdown alleviates palmitate-induced insulin resistance in HepG2 cells through NF-κB pathway.

High-fat diet (HFD) and inflammation are key contributors to insulin resistance (IR) and Type 2 diabetes mellitus (T2DM). With HFD, plasma free fatty acids (FFAs) can activate the nuclear factor-κB (NF-κB) in target tissues, then initiate negative crosstalk between FFAs and insulin signaling. However, the molecular link between IR and inflammation remains to be identified. We here reported that tumor necrosis factor receptor-associated factor 1 (TRAF1), an adapter in signal transduction, was involved in the onset of IR in hepatocytes. TRAF1 was significantly up-regulated in insulin-resistant liver tissues and palmitate (PA)-treated HepG2 cells. In addition, we showed that depletion of TRAF1 led to inhibition of the activity of NF-κB. Given the fact that the activation of NF-κB played a facilitating role in IR, the phosphorylation of Akt and GSK3ß was also analyzed. We found that depletion of TRAF1 markedly reversed PA-induced attenuation of the phosphorylation of Akt and GSK3ß in the cells. The accumulation of lipid droplets in hepatocyte and expression of two key gluconeogenic enzymes, PEPCK and G6Pase, were also determined and found to display a similar tendency with the phosphorylation of Akt and GSK3ß. Glucose uptake assay indicated that knocking down TRAF1 blocked the effect of PA on the suppression of glucose uptake. These data implicated that TRAF1 knockdown might alleviate PA-induced IR in HepG2 cells through NF-κB pathway.

The expression level of TRAF1 in human gastric mucosa is related to virulence genotypes of Helicobacter pylori.

OBJECTIVE: To investigate the expression level of tumor necrosis factor receptor-associated factor 1 (TRAF1) in gastric mucosa tissue in patients infected with Helicobacter pylori (H. pylori) and to analyze the relationship between TRAF1 expression and H. pylori virulence. METHODS: Gastric tissue samples were collected from patients with gastritis, atrophic gastritis, intestinal metaplasia with atypical hyperplasia, and gastric cancer. The expression level of TRAF1 in each group was analyzed by real-time polymerase chain reaction (PCR) and Western blot analysis. Virulence genotypes of H. pylori were determined by PCR. RESULTS: Significant differences in TRAF1 mRNA levels were observed between the gastritis and gastric cancer groups, and the atrophic gastritis and gastric cancer groups (p < 0.05). Moreover, significant differences in TRAF1 protein levels were observed between the gastritis and intestinal metaplasia with atypical hyperplasia groups, between the gastritis and gastric cancer groups, and between the atrophic gastritis and gastric cancer groups (all p < 0.05). The virulence genotypes of cytotoxin-associated gene A (cagA), vacAs1, and vacAm1 were more frequent in the TRAF1 high-level group than in the TRAF1 low-level group (p < 0.05). CONCLUSION: Higher TARF1 expression level is associated with infection by CagA(+)/vacAs1(+)/m1(+) virulent H. pylori strains and may promote the proliferation of gastric mucosal cells and induce gastric cancer.