Analysis Of Tumor Necrosis Factor Research Articles

Bibliometric analysis of tumor necrosis factor in post-stroke neuroinflammation from 2003 to 2021.

Tumor necrosis factor (TNF), a crucial cytokine, has important research value in post-stroke neuroinflammation (PSN). We analyzed the studies that have been conducted in this area and used bibliometric methods to predict research hotspots and identify trends regarding TNF in PSN. Publications were accessed at the Science Citation Index Expanded 1975-2021 (SCI expanded), Web of Science Core Collection (WoSCC), on May 1, 2022. Additionally, software such as CiteSpace and VOSviewer were utilized for bibliometric analyses. In total, 1391 original articles and reviews on TNF in PSN published from 2003 to 2021 were identified. An upward trend was observed in the number of publications on TNF in PSN. These publications were primarily from 57 countries and 1446 institutions, led by China and the United States with China leading the number of publications (NP) and the US with the number of citations (NC). The League of European Research Universities (LERU) and Journal of Neuroinflammation, respectively were the most prolific branches and journals. Zhang, John H. published the most papers and Finsen, Bente had the most cited papers. One paper by Kettenmann, H. published in 2011 reached the highest level of Global Citation Score (GCS). The keyword co-occurrence and reference co-citation analyses suggest that poststroke therapy and potential mechanistic pathways are important topics related to PSN in recent years. Reference burst detection suggests new burst hotspots after 2015, focusing on pathway modulation and discovery of therapeutic targets, suggesting a substantial development in the study of TNF in PSN research. The present bibliometric analysis shows a continuous trend of increasing literature related to TNF in PSN, and shows that TNF plays an important role in PSN involves multiple immune mechanisms and may contribute as a potential target for neuroprotective therapeutics after stroke. Prior to 2011, most of the research was focused on discovering the specific role of TNF in PSN, and in recent years studies have mainly targeted the exploration of the signaling pathways. Future research prospects may lie in finding key therapeutic targets in pathway of TNF in PSN.

Inhibitory activity of flaxseed oil against CdCl2 induced liver and kidney damage: Histopathology, genotoxicity, and gene expression study

The present work evaluated the effect of flaxseed oil (FO) against toxicity induced by cadmium chloride (CdCl2) in the mouse liver and kidney. Male Swiss albino mice were treated with CdCl2 (4.5 mg/kg, intraperitoneally) with or without FO at three concentrations (4, 8, 12 mL/kg, orally) for two consecutive weeks. To analyze the effects of FO, we used the following techniques: (1) histopathological examination; (2) comet assay; (3) RT-PCR gene expression analysis of tumor necrosis factor (TNF-α) and tumor suppressor protein (p53); and (4) immunohistochemical analysis of caspase-9 protein expression. The gas chromatography-mass spectrometry results showed that FO had a high content of unsaturated fatty acids including, oleic acid, linolenic acid, and linoleic acid. Oral supplementation with FO (12 mL/kg) resulted in a normal histological appearance without alteration in the DNA integrity and gene expression of TNF-α, p53, and caspase-9 in liver and kidney tissues. As expected, CdCl2 remarkably induced loss of histological integrity, increased DNA comet formation, increased TNF-α and p53 mRNA expression levels and increased the immunoreactivity of caspase-9 expression. When FO was given before administration of CdCl2, these histopathological defects were reversed; necrosis, degeneration, inflammatory cell infiltration, hemorrhage, Kupffer cells, and pyknotic cells were all reduced. These histological improvements induced by FO were accompanied by reduced DNA breakage, downregulated mRNA expression of TNF-α and p53, and downregulated immunohistochemical expression of caspase-9 protein. In conclusion, FO and its constituents may act as signaling molecules and modify the expression of genes involved in proinflammatory cytokine production (TNF-α), cell cycle arrest (p53), and apoptosis (caspase-9), thereby improving biological activities and health.

Integrated proteomic analysis of tumor necrosis factor α and interleukin 1β-induced endothelial inflammation

The vascular endothelium provides a unique interaction plane for plasma proteins and leukocytes in inflammation. The pro-inflammatory cytokines Tumor Necrosis Factor α (TNFα) and interleukin 1β (IL-1β) have a profound effect on endothelial cells, which includes increased levels of adhesion molecules and a disrupted barrier function. To assess the endothelial response to these cytokines at the protein level, we evaluated changes in the whole proteome, cell surface proteome and phosphoproteome after 24 h of cytokine treatment. The effects of TNFα and IL-1β on endothelial cells were strikingly similar and included changes in proteins not previously associated with endothelial inflammation. Temporal profiling revealed time-dependent proteomic changes, including a limited number of early responsive proteins such as adhesion receptors ICAM1 and SELE. In addition, this approach uncovered a greater number of late responsive proteins, including proteins related to self-antigen peptide presentation, and a transient increase in ferritin. Peptide-based cell surface proteomics revealed extensive changes at the cell surface, which were in agreement with the whole proteome. In addition, site-specific changes within ITGA5 and ICAM1 were detected. Combined, our integrated proteomic data provide detailed information on endothelial inflammation, emphasize the role of the extracellular matrix therein, and include potential targets for therapeutic intervention. SignificancePro-inflammatory cytokines induce the expression of cell adhesion molecules in vascular endothelial cells. These molecules mediate the adhesion and migration of immune cells across the vessel wall, which is a key process to resolve infections in the underlying tissue. Dysregulation of endothelial inflammation can contribute to vascular diseases and the vascular endothelium is therefore an attractive target to control inflammation. Current strategies targeting endothelial adhesion molecules, including PECAM, CD99, ICAM1 and VCAM1 do not completely prevent transmigration. To identify additional therapeutic targets, we mapped the endothelial proteome after pro-inflammatory cytokine treatment. In addition to the whole proteome, we assessed the surface proteome to focus on cell adhesion molecules, and the phosphoproteome to uncover protein activation states. Here, we present an integrated overview of affected processes which further improves our understanding of endothelial inflammation and may eventually aid in therapeutic intervention of imbalanced inflammation.

Computation and measurement of cell decision making errors using single cell data.

In this study a new computational method is developed to quantify decision making errors in cells, caused by noise and signaling failures. Analysis of tumor necrosis factor (TNF) signaling pathway which regulates the transcription factor Nuclear Factor κB (NF-κB) using this method identifies two types of incorrect cell decisions called false alarm and miss. These two events represent, respectively, declaring a signal which is not present and missing a signal that does exist. Using single cell experimental data and the developed method, we compute false alarm and miss error probabilities in wild-type cells and provide a formulation which shows how these metrics depend on the signal transduction noise level. We also show that in the presence of abnormalities in a cell, decision making processes can be significantly affected, compared to a wild-type cell, and the method is able to model and measure such effects. In the TNF—NF-κB pathway, the method computes and reveals changes in false alarm and miss probabilities in A20-deficient cells, caused by cell’s inability to inhibit TNF-induced NF-κB response. In biological terms, a higher false alarm metric in this abnormal TNF signaling system indicates perceiving more cytokine signals which in fact do not exist at the system input, whereas a higher miss metric indicates that it is highly likely to miss signals that actually exist. Overall, this study demonstrates the ability of the developed method for modeling cell decision making errors under normal and abnormal conditions, and in the presence of transduction noise uncertainty. Compared to the previously reported pathway capacity metric, our results suggest that the introduced decision error metrics characterize signaling failures more accurately. This is mainly because while capacity is a useful metric to study information transmission in signaling pathways, it does not capture the overlap between TNF-induced noisy response curves.

Structural biology of tumor necrosis factor demonstrated for undergraduates instruction by computer simulation

This work presents a three-dimensional (3D) modeling exercise for undergraduate students in chemistry and health sciences disciplines, focusing on a protein-group linked to immune system regulation. Specifically, the exercise involves molecular modeling and structural analysis of tumor necrosis factor (TNF) proteins, both wild type and mutant. The structure of the tumor necrosis factor type 1 receptor (TNF-R1) is also briefly explored. TNF and TNF-R1 play major roles in maintaining human immune-system homeostasis. Upon binding with TNFR-1, the TNF can activate the nuclear factor kappa B (NF-κB), eventually resulting in apoptosis or cell death. These essential features of the clinically relevant TNF family is explored within the frame work of a readily adaptable tutorial. © 2015 by The International Union of Biochemistry and Molecular Biology, 44:246-255, 2016.

Omega-3 polyunsaturated fatty acid and ursodeoxycholic acid have an additive effect in attenuating diet-induced nonalcoholic steatohepatitis in mice.

Nonalcoholic steatohepatitis (NASH) can progress into liver cirrhosis; however, no definite treatment is available. Omega-3 polyunsaturated fatty acid (omega-3) has been reported to alleviate experimental NASH, although its beneficial effect was not evident when tested clinically. Thus, this study aimed to investigate the additive effect of omega-3 and ursodeoxycholic acid (UDCA) on diet-induced NASH in mice. C57BL/6 mice were given a high-fat diet (HFD) for 24 weeks, at which point the mice were divided into three groups and fed HFD alone, HFD with omega-3 or HFD with omega-3 in combination with UDCA for another 24 weeks. Feeding mice an HFD and administering omega-3 improved histologically assessed liver fibrosis, and UDCA in combination with omega-3 further attenuated this disease. The assessment of collagen α1(I) expression agreed with the histological evaluation. Omega-3 in combination with UDCA resulted in a significant attenuation of inflammation whereas administering omega-3 alone failed to improve histologically assessed liver inflammation. Quantitative analysis of tumor necrosis factor α showed an additive effect of omega-3 and UDCA on liver inflammation. HFD-induced hepatic triglyceride accumulation was attenuated by omega-3 and adding UDCA accentuated this effect. In accordance with this result, the expression of sterol regulatory binding protein-1c decreased after omega-3 administration and adding UDCA further diminished SREBP-1c expression. The expression of inducible nitric oxide synthase (iNOS), which may reflect oxidative stress-induced tissue damage, was suppressed by omega-3 administration and adding UDCA further attenuated iNOS expression. These results demonstrated an additive effect of omega-3 and UDCA for alleviating fibrosis, inflammation and steatosis in diet-induced NASH.

Effects of supplemental chromium propionate and rumen-protected amino acids on nutrient metabolism, neutrophil activation, and adipocyte size in dairy cows during peak lactation

The objective of this study was to evaluate effects of chromium propionate (CrPr), rumen-protected lysine and methionine (RPLM), or both on metabolism, neutrophil function, and adipocyte size in lactating dairy cows (38±15d in milk). Forty-eight individually fed Holstein cows (21 primiparous, 27 multiparous) were stratified by calving date in 12 blocks and randomly assigned to 1 of 4 treatments within block. Treatments were control, CrPr (8mg/d of Cr, KemTRACE brand chromium propionate 0.04%, Kemin Industries Inc., Des Moines, IA), RPLM (10g/d lysine and 5g/d methionine intestinally available, from LysiPEARL and MetiPEARL, Kemin Industries Inc.), or CrPr plus RPLM. Treatments were fed for 35 d; blood plasma samples were collected ond 21 and 35 of treatment, and blood neutrophils were isolated from 24 cows for analysis of tumor necrosis factor α (TNFα) and interleukin 1β (IL-1β) transcript abundance in the basal state and after 12h of lipopolysaccharide (LPS) activation. Tailhead subcutaneous adipose tissue samples were collected ond 35 for measurement of adipocyte size. Plasma glucose, nonesterified fatty acids, and glucagon concentrations were unaffected by treatments, whereas plasma insulin concentration was increased by RPLM. Basal TNFα transcript abundance in neutrophils was not affected by treatment, but basal IL-1β transcript abundance was decreased by RPLM and tended to be increased by CrPr. After LPS activation, CrPr increased neutrophil TNFα transcript abundance. In addition, RPLM×parity interactions were detected for both TNFα and IL-1β abundance after LPS activation, reflecting enhanced responses in primiparous cows and attenuated responses in multiparous cows supplemented with RPLM. Adipocyte size was not affected by treatment. Supplemental CrPr and RPLM had minimal effects on metabolism when fed for 35d near peak lactation but may modulate innate immune function in lactating dairy cows.

Antitumor Activity of a Novel Homodimeric SMAC Mimetic in Ovarian Carcinoma

Treatment of ovarian carcinoma often fails to be curative because of drug resistance, and many efforts are directed to overcome tumor cell resistance by increasing apoptosis induction. The potential of second mitochondria-derived activator of caspases (SMAC) mimetics (SMACm) has appeared in preclinical studies, but novel proapoptotic agents of this class with improved pharmacological profile are needed. To identify novel treatment options for ovarian carcinoma by interfering with antiapoptotic factors, in the present study a novel homodimeric SMACm (SM83) was employed in preclinical models both in vitro and in vivo. An investigation of the structural features of dimeric SM83 as compared to a closely related reference compound indicated slight differences, likely because of the interaction between one of the terminal phenyl groups and triazole rings of SM83 with the BIR2 domain. Although SM83 per se did not inhibit cell proliferation, it displayed a synergistic effect in combination with TNF-related apoptosis inducing ligand (TRAIL) in cell sensitivity assays. Because the tumor microenvironment is a reservoir of cytokines that may act in conjunction with SMACm to affect tumor growth, the activity of the novel compound was tested in vivo in ovarian carcinoma cells subcutaneously xenografted into immunodeficient mice. A significant tumor volume inhibition was observed together with activation of caspase 3 and apoptotic cell death. A biochemical analysis of tumor necrosis factor (TNF) and TRAIL content in specimens from xenografted mice indicated that SM83 downmodulated the levels of human TNF in plasma samples and tended to upmodulate human TRAIL levels in tumors. Thus, TRAIL appears to contribute to the antitumor activity of novel SMACm SM83 in subcutaneously grown ovarian carcinoma. Overall, our results indicate that SM83 is an attractive candidate for further development.

Inhibition of indoleamine 2,3-dioxygenase prevented cognitive impairment in adult Wistar rats subjected to pneumococcal meningitis

Streptococcus pneumoniae is a common cause of forms of bacterial meningitis that have a high mortality rate and cause long-term neurologic sequelae. We evaluated the effects of an indoleamine 2,3-dioxygenase (IDO) inhibitor on proinflammatory mediators and memory in Wistar rats subjected to pneumococcal meningitis. The animals were divided into 4 groups: sham, sham treated with IDO inhibitor, meningitis, and meningitis treated with IDO inhibitor. During the first experiment, the animals were killed 24 hours later, and the hippocampus was isolated for the analysis of tumor necrosis factor (TNF)-α, interleukin (IL)-4, IL-6, IL-10, and cytokine-induced neutrophil chemoattractant 1 (CINC-1) levels. The survival rate was 56.296% in the meningitis group and 29.616% in the meningitis group with IDO inhibitor. In the control group, we found a mean of 14.29 white blood cells/mL cerebrospinal fluid, whereas the mean was 80.00 white blood cells/mL cerebrospinal fluid in the sham IDO inhibitor group, 1167.00 white blood cells/mL cerebrospinal fluid in the meningitis group, and 286.70 white blood cells/mL cerebrospinal fluid in the meningitis IDO inhibitor group. In the meningitis group with IDO inhibitor, the levels of TNF-α and CINC-1 were reduced. In the second experiment, animals were subjected to a behavioral task and cytokine analysis 10 days after meningitis induction. In the meningitis group, there was an impairment of aversive memory. However, in the meningitis group that received adjuvant treatment with the IDO inhibitor, animals demonstrated preservation of aversive memory. These findings showed dual effects of the IDO inhibitor on a pneumococcal meningitis animal model because the inhibitor impaired survival but also produced beneficial effects, including anti-inflammatory activity and neuroprotection against the latter behavioral deficits.

Brief Report: Large‐scale analysis of tumor necrosis factor α levels in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) disease manifestations are highly variable among patients, and the prevalence of individual clinical features differs significantly by ancestry. Serum tumor necrosis factor α (TNFα) levels are elevated in some SLE patients and may play a role in disease pathogenesis. The aim of this study was to look for associations between serum TNFα levels, clinical manifestations of SLE, autoantibodies, and serum interferon-α (IFNα) levels in a large multiancestral SLE cohort. We studied serum TNFα levels in 653 SLE patients (214 African Americans, 298 European Americans, and 141 Hispanic Americans). TNFα was measured using an enzyme-linked immunosorbent assay, and IFNα was measured with a functional reporter cell assay. Stratified and multivariate analyses were used to detect associations in each ancestral background separately, with meta-analysis when appropriate. Serum TNFα levels were significantly higher in SLE patients than in non-autoimmune disease controls (P < 5.0 × 10(-3) for each ancestral background). High serum TNFα levels were positively correlated with high serum IFNα levels when tested in the same sample across all ancestral backgrounds (odds ratio range 1.76-1.86, P = 4.8 × 10(-3) by Fisher's combined probability test). While serum TNFα levels alone did not differ significantly among SLE patients of different ancestral backgrounds, the proportion of patients with concurrently high levels of TNFα and IFNα was highest in African Americans and lowest in European Americans (P = 5.0 × 10(-3) ). Serum TNFα levels were not associated with autoantibodies, clinical criteria for the diagnosis of SLE, or age at the time of sampling. Serum TNFα levels are high in many SLE patients, and we observed a positive correlation between serum TNFα and IFNα levels. These data support a role for TNFα in the pathogenesis of SLE across all ancestral backgrounds and suggest important cytokine subgroups within the disease.

Lack of association between TNF-α gene polymorphisms at position -308 A, -850T and risk of simple febrile convulsion in pediatric patients

Background:Febrile convulsions (FCs), occurring between 6 months and 6 years of age is the most common seizure disorder during childhood. The febrile response is thought to be mediated by the release of pyrogenic cytokines, such as tumor necrosis factor and interleukin-1 (IL-1). There is a significant relationship between genetic components for susceptibility of FCs and different report mutation. We investigated association between two polymorphisms in the tumor necrosis factor (TNF)-α promoter region (G-308A, C-850T) and FCs in the southwest area of Iran.Materials and Methods:In this matched case–control study, 100 patients with febrile convulsion as case group and 130 healthy children as control group were enrolled in the study. Peripheral blood samples were collected and DNA was extracted by standard phenol–chloroform method. The genotype and allele frequencies of TNF- α polymorphisms in case and control groups were determined by using PCR-RFLP (polymerase chain reaction restriction fragment length polymorphism) method. Statistical analysis was done using Chi-square test.Results:The average age of case and control groups were 3.4 ± 1.4 and 3.4 ± 1.2 years, respectively. There was no significant difference between age and sex in both the groups (P > 0.05). A family history of febrile convulsion was detected in 44% of patients. Moreover, the simple febrile convulsion was detected in 85% of the case group.Conclusion:RFLP analysis of TNF- α promoter region polymorphisms, considering P = 0.146 and P = 0.084 for G-308A and C-850T, respectively, showed no correlation between TNF- α polymorphisms and predisposition to simple febrile, based on the kind of convulsion (atypical and simple febrile convulsion). We found a significant relation between genotype distribution of G-308A and atypical febrile convulsion in case group (P = 0.04). A significant correlation between genotype distribution of G-308A and atypical febrile convulsion in the case group was found, but there was no correlation between TNF- α polymorphisms at positions of -308A, and 850T and predisposition to simple febrile convulsion. Further studies are needed to understand clinical usefulness of this correlation.

Delayed Dominant-Negative TNF Gene Therapy Halts Progressive Loss of Nigral Dopaminergic Neurons in a Rat Model of Parkinson's Disease

Parkinson's disease (PD) is a progressive neurodegenerative disorder typified by the loss of dopaminergic (DA) neurons in the substantia nigra pars compacta (SNpc). Recent evidence indicates that neuroinflammation may play a critical role in the pathogenesis of PD, particularly tumor necrosis factor (TNF). We have previously shown that soluble TNF (solTNF) is required to mediate robust degeneration induced by 6-hydroxydopamine (6-OHDA) or lipopolysaccharide. What remains unknown is whether TNF inhibition can attenuate the delayed and progressive phase of neurodegeneration. To test this, rats were injected in the SNpc with lentivirus encoding dominant-negative TNF (lenti-DN-TNF) 2 weeks after receiving a 6-OHDA lesion. Remarkably, when examined 5 weeks after the initial 6-OHDA lesion, no further loss of nigral DA neurons was observed. Lenti-DN-TNF also attenuated microglial activation. Together, these data suggest that TNF is likely a critical mediator of nigral DA neuron death during the delayed and progressive phase of neurodegeneration, and that microglia may be the principal cell type involved. These promising findings provide compelling reasons to perform DN-TNF gene transfer studies in nonhuman primates with the long-term goal of using it in the clinic to prevent the delayed and progressive degeneration of DA neurons that gives rise to motor symptoms in PD.

Isomaltitol Exacerbates Neutrophilia but Reduces Eosinophilia: New Insights into the Sephadex Model of Lung Inflammation

Background: We have previously examined isomaltitol in an in vitro static adhesion assay and were interested in investigating whether the potentially anti-inflammatory effects observed there could be relevant in vivo. The Sephadex-induced lung inflammation model was considered a suitablemodel due to the significant changes in global inflammatory endpoints seen upon provocation with Sephadex. Methods: Male Sprague-Dawley rats were instilled intratracheally with Sephadex (5 mg/ml), vehicle (0.9% NaCl), isomaltitol (50 mg/ml) or a combination of isomaltitol and Sephadex. After 24 h, the lungs were weighed to measure edema and preserved for histology. Bronchoalveolar lavage fluid was used for analysis of tumor necrosis factor, cysteinyl leukotrienes, and differential and total leukocyte counts. Results: Differential counts showed that isomaltitol increased the neutrophil component while decreasing the eosinophilia, thus asserting a modulatory role on the usually eosinophil-dominated Sephadex-induced cell profile. Isomaltitol alone also increased edema and cysteinyl leukotrienes, and generally aggravated total inflammation in combination with Sephadex. The mechanisms were not investigated in this study, but effects could relate to a combination of isomaltitol’s osmotic and structure-specific properties. Conclusion: Our results show that isomaltitol can modulate the inflammatory response induced by Sephadex instillation in addition to having proinflammatory effects on its own, and may therefore provide new insights into the mechanisms of this widely used animal model. Sugar alcohols similar to isomaltitol have already been used to aid mucus clearance in cystic fibrosis patients, and it is possible that isomaltitol could also be used for this purpose.

Family-based analysis of tumor necrosis factor and lymphotoxin-α tag polymorphisms with type 1 diabetes in the population of South Croatia

Tumor necrosis factor (TNF) and lymphotoxin-α (LTA) are cytokines with a wide range of inflammatory and immunomodulatory activities. Type 1 diabetes is an autoimmune disease characterized by destruction of insulin-producing pancreatic β cells. The aim of the present study was to evaluate the association of polymorphisms in the TNF/ LTA gene region with susceptibility to type 1 diabetes. We investigated 11 TNF/ LTA tag polymorphisms, designed to capture the majority of common variation in the region, in 160 trio families from South Croatia. We observed overtransmission of alleles from parents to affected child at five variants: (rs909253, allele C, p = 1.2×10 −4; rs1041981, allele A, p = 1.1×10 −4; rs1800629 (G-308A), allele A, p = 1.2×10 −4; rs361525 (G-238A), allele G, p = 8.2×10 −3 and rs3093668, allele G, p = 0.014). We also identified overtransmission of the rs1800629(G-308A)-rs361525(G-238A) A-G haplotype, p = 2.384×10 −5. The present study found an association of the TNF/ LTA gene region with type 1 diabetes. A careful assessment of TNF/ LTA variants adjusted for linkage disequilibrium with HLA loci is needed to further clarify the role of these genes in type 1 diabetes susceptibility in the population of South Croatia.

Polymorphisms of the TNF, CD14, and HSPA1B Genes in Patients With Acute Alcohol-Induced Pancreatitis

Genotype assessment has been suggested to be a tool for predicting disease severity in acute pancreatitis (AP). To study this hypothesis, we performed genotype analysis of tumor necrosis factor (TNF) -308 A/G, CD14 -159C/T, and HSPA1B +1267 A/G polymorphisms. This is a case-control association study of 397 patients with AP (214 of whom had an alcohol-induced AP) and 300 controls. The control group comprised 218 subjects with detailed data of alcohol consumption, 70 of whom were heavy drinkers (daily alcohol intake >40 g), and 92 blood donors. The severity of AP was determined according to the Atlanta classification. Genotyping was performed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry-assisted genotyping method. Major allele frequency in TNF gene was 0.87 for patients with AP and 0.86 for controls. For CD14, the gene major allele frequency was 0.60 for patients and 0.63 for controls. For HSPA1B, the major allele frequencies were 0.52 for patients and 0.49 for controls, respectively. The allele frequencies did not differ significantly between AP patients with organ failure and those with mild disease, patients with alcohol-induced AP, or those with biliary AP. The patients with septic infectious complications (n = 47) had genotype distribution no different from those with mild, uncomplicated disease (n = 245). The TNF, CD14, and HSPA1B polymorphisms studied seem not to play a role in determining the severity of AP or the risk of alcohol-induced AP and thus do not serve as a tool for predicting disease severity.

Mass spectrometric analysis of tumor necrosis factor receptor-associated factor 1 ubiquitination mediated by cellular inhibitor of apoptosis 2.

Signaling complexes formed on tumor necrosis factor receptor 2 (TNF-R2) contain adaptor proteins TNF-R-associated factors (TRAFs) 1 and 2, and cellular inhibitors of apoptosis (cIAPs) 1 and 2 which function as regulators of programmed cell death. TRAF2, cIAP1 and cIAP2 all have RING finger domains known to possess E3 ubiquitin ligase activity, implying that ubiquitination may play an important role in the TNF signaling pathway. In this report, we have shown that cIAP2 specifically mediated ubiquitination and proteasome-dependent degradation of TRAF1. To identify the sites for cIAP2-mediated ubiquitination of TRAF1, we used high pressure liquid chromatography coupled with tandem mass spectrometry. Lys185 and Lys193 of TRAF1 were found to be modified with ubiquitin chains. Mutation of Lys185 and Lys193 to Arg almost completely blocked cIAP2-mediated ubiquitination of TRAF1, indicating that they are the major, if not the only, sites of TRAF1 ubiquitination. Our data suggest that cIAP2 may regulate the turnover of TRAF1 by adding polyubiquitin chains on Lys185 or Lys193 following its recruitment to TNF-R signaling complexes.

An analysis of tumor necrosis factor alpha gene polymorphisms and haplotypes with natural clearance of hepatitis C virus infection.

The cytokine tumor necrosis factor alpha (TNF-alpha) is important in generating an immune response against a hepatitis C virus (HCV) infection. The functions of TNF-alpha may be altered by single-nucleotide polymorphisms (SNPs) in its gene, TNF. We hypothesized that SNPs in TNF may be important in determining the outcome of an HCV infection. To test this hypothesis, we typed nine TNF SNPs in a cohort of individuals with well-defined HCV outcomes. Three of these SNPs were typed in a second cohort. Data were analyzed using logistic regression stratifying by ethnicity, since rates of HCV clearance differ in black subjects versus white subjects. The SNP -863A was associated with viral clearance in black subjects (odds ratios (OR) 0.52, 95% confidence interval (CI) 0.29-0.93). Furthermore, the common wild-type haplotype -863C/-308G was associated with viral persistence in black subjects (OR 1.91, 95% CI 1.24-2.95). These findings were independent of linkage with human leukocyte antigen (HLA) alleles. Further study of this polymorphism and haplotype is needed to understand these associations and the role of TNF-alpha in determining outcomes of HCV infection.

Molecular identification and expression analysis of tumor necrosis factor in channel catfish ( Ictalurus punctatus)

A tumor necrosis factor (TNF) α-like gene, encoding a propeptide of 230 amino acids and a mature (soluble) peptide of 162 amino acids, was identified in channel catfish ( Ictalurus punctatus). While the catfish protein shared features in common with both mammalian TNFα and TNFβ homologs, overall sequence identity/similarity was slightly higher vs. TNFα genes when mature TNF sequences were compared. Phylogenetic analysis placed catfish and other fish TNF sequences within their own cluster apart from mammalian TNFα and β genes, and supported the suggestion that TNFα and β genes separated after the divergence of mammals and teleosts. In contrast to trout and carp, but similar to flounder, catfish TNF was present as a single copy gene. Expression studies demonstrated that catfish TNFα mRNA was present in all tested tissues (i.e. liver, spleen, head kidney, mesonephros, gill, thymus, and PBLs) from an unstimulated fish. Moreover, catfish TNF was constitutively expressed in actively proliferating, but otherwise unstimulated, macrophage (42TA) and T cell (G14D; TS32.17) lines, but not in B cell (1G8 or 3B11) or fibroblast lines. TNF expression was upregulated in PBLs, and in G14D and 42TA cells, but not in 3B11 cells, by PMA/calcium ionophore treatment. These results demonstrate that a catfish homolog of TNFα has been identified, and indicate that catfish TNFα is expressed in catfish in a manner similar to that seen in mammals.

Molecular cloning and sequencing of partial cDNA of tumor necrosis factor and p75 tumor necrosis factor receptor of Syrian golden hamster (Mesocricetus auratus) with the use of universal primers.

In this study we cloned and analysed partial cDNA of tumor necrosis factor (TNF) and p75 TNF-R receptor of Syrian golden hamster (Mesocricetus auratus). We obtained a 382-bp sequence of TNF and a 148-bp sequence coding for p75 TNF-R. The primers used for the cloning were designed on the basis of inter-species homology, thus presumably can be used for cloning and analysis of TNF and p75 TNF-R genes of other mammals.

Molecular cloning and expression analysis of tumor necrosis factor alpha from a marine fish reveal its constitutive expression and ubiquitous nature.

The tumor necrosis factor alpha ( TNF alpha) gene from the marine fish, gilthead seabream (Sparus aurata L.), has been isolated by RT-PCR using degenerate primers designed against vertebrate TNF alpha conserved motifs and subsequent rapid amplification of cDNA ends (RACE). The TNF alpha cDNA consists of a 142 bp 5' untranslated region (5'UTR), a single open reading frame of 762 bp, which could code for a 253 amino acid protein, and a 476-bp 3'UTR. The protein sequence deduced from seabream TNF alpha gene shows a high degree of homology with the Japanese flounder TNF alpha (65.6% identity and 78.9% similarity) and, more important, it is more homologous to mammalian TNF alphas (41.1-48.6% similarity) than to TNF betas (36.0-43.5% similarity). The prediction of a transmembrane domain between residues 37 and 54 of seabream TNF alpha and the presence of a conserved Thr-Leu sequence, which is associated with cleavage of the mouse TNF alpha molecule, suggest that seabream TNF alpha exists in two forms, a membrane-bound and a soluble form. RT-PCR shows that the seabream TNF alpha messenger was widely and constitutively accumulated. Lastly, stimuli known to up-regulate seabream IL-1 beta, lipopolysaccharide and lymphocyte-derived macrophage-activating factor, failed to up-regulate TNF alpha in cultured macrophages. The putative role of three AU-rich endotoxin-responsive motifs (AREs) of seabream TNF alpha mRNA, found within two phylogenetically conserved protein binding regions, is discussed.