TNF Molecules Research Articles

Soluble Plasma Proteins of Tumor Necrosis Factor and Immunoglobulin Superfamilies Reveal New Insights into Immune Regulation in People with HIV and Opioid Use Disorder.

People with HIV (PWH) frequently suffer from Opioid (OP) Use Disorder (OUD). In an investigation of the impact of OUD on underlying immune dysfunction in PWH, we previously reported that OP use exacerbates inflammation in virally controlled PWH followed in the Infectious Diseases Elimination Act (IDEA) Syringe Services Program (SSP). Unexpectedly, Flu vaccination-induced antibody responses in groups with OUD were superior to PWH without OUD. Here, we investigated the profile of 48 plasma biomarkers comprised of TNF and Ig superfamily (SF) molecules known to impact interactions between T and B cells in 209 participants divided into four groups: (1) HIV+OP+, (2) HIV-OP+, (3) HIV+OP-, and (4) HIV-OP-. The differential expression of the top eight molecules ranked by median values in individual Groups 1-3 in comparison to Group 4 was highly significant. Both OP+ groups 1 and 2 had higher co-stimulatory TNF SF molecules, including 4-1BB, OX-40, CD40, CD30, and 4-1BBL, which were found to positively correlate with Flu Ab titers. In contrast, HIV+OP- exhibited a profile dominant in Ig SF molecules, including PDL-2, CTLA-4, and Perforin, with PDL-2 showing a negative correlation with Flu vaccine titers. These findings are relevant to vaccine development in the fields of HIV and OUD.

TNF-α and its soluble receptors mediate the relationship between prior severe mood episodes and cognitive dysfunction in euthymic bipolar disorder

BackgroundBipolar disorder (BD) is one of the most disabling mental health conditions in the world. Symptoms of cognitive impairment in BD contribute directly to occupational and social deficiencies and are very difficult to treat. Converging evidence suggests that BD patients have increased peripheral markers of inflammation. The hypothesis of neuroprogression in BD postulates that cognitive deficits develop over the course of the illness and are influenced by prior severe mood episodes, leading to wear-and-tear on the brain– however, there exists a paucity of data statistically testing a mediating role of immune molecules in cognitive dysfunction in BD. MethodsThis is a cross-sectional study. We measured serum levels of tumor necrosis factor alpha (TNF-α), and soluble (s) TNF receptors one and two (sTNF-R1 and sTNF-R2) in 219 euthymic BD patients and 52 Healthy Controls (HCs). Structural equation modeling (SEM) was used for the primary purpose of assessing whether TNF markers (measured by the multiple indicators TNF-α, sTNF-R1 and sTNF-R2) mediate the effect or number of prior severe mood episodes (number of prior psychiatric hospitalizations) on cognitive performance. ResultsBD and HC groups did not differ on circulating levels of TNF molecules in the present study. However, we found higher sTNF-R1 concentration in ‘late-stage’ BD illness (>1 prior psychiatric hospitalization) compared to those in early stage illness. In the subsequent SEM, we found that the model fits the data acceptably (Chi-square = 49.2, p = 0.3), and had a ‘close fit’ (RMSEA = 0.02, PCLOSE = 0.9). Holding covariates constant (age, sex, premorbid IQ, education, and race), we found that the standardized indirect effect was significant, p = 0.015, 90%CI [-0.07, −0.01], indicating that the estimated model was consistent with peripheral TNF markers partially mediating a causal effect of severe mood episodes on executive function. ConclusionsOur results indicate that circulating levels of TNF molecules partially mediate the relationship between prior severe mood episodes and executive function in BD. These results may implicate TNF variables in the neuroprogressive course of BD and could point to novel interventions for cognition.

Diagnosis and treatment of rheumatoid arthritis:toward the best practice. Change in immune phenotype by the treatment of rheumatoid arthritis.

Considerable advance in the treatment of rheumatoid arthritis has been made following the advent of biological disease-modifying anti-rheumatic drugs that target TNF, IL-6 and co-stimulatory molecules. In addition, the introduction of molecular targeted drugs triggered accelerating translational research from the bedside to the bench. One example is immunophenotyping analysis using peripheral blood from patients. Accumulating evidences suggest that molecular targeted therapies induced different changes in different immune cell phenotypes involving both innate immunity and acquired immunity. Immunophenotypic analysis might be useful in evaluating the immune signatures and in predicting the therapeutic efficacy for individual patients.

Microarray profiling provides insights into mechanisms of mesenchymal stem cells-mediated immunomodulation of activated microglia

Event Abstract Back to Event Microarray profiling provides insights into mechanisms of mesenchymal stem cells-mediated immunomodulation of activated microglia Shinsmon Jose1*, Soon C. Chan2, King-Hwa Ling3, Abhi Veerakumarasivam3 and Sharmili Vidyadaran1 1 Universiti Putra Malaysia, Neuroinflammation Group, Immunology Laboratory, Department of Pathology, Faculty of Medicine Health Sciences, Malaysia 2 Perdana University , Graduate School of Medicine (PUGSOM), Malaysia 3 Universiti Putra Malaysia, Medical Genetics Laboratory, Faculty of Medicine and Health Sciences, Malaysia Mesenchymal stem cell’s (MSC) potential to exert an immunomodulatory effect on activated microglia is known for over a decade. However, the mechanism of immunomodulation is poorly understood. Here, we employ a microarray [Agilent] to first define the genes expressed in microglia following an inflammatory stimuli [LPS] and secondly to elucidate the effects exerted by MSC on those genes. Transcriptome level responses to LPS and MSC were determined based on differentially expressed gene (DEG) profile of Refseq annotated genes compared to unstimulated microglia (p<0.05, FC>2). A total of 428 genes were differentially expressed in LPS-stimulated microglia compared to 449 in activated co-culture. Gene ontology of DEGs in these two groups using DAVID Bioinformatics online tool were similar. However, a close examination of DEGs revealed that co-culture with MSC downregulated the expression of inflammatory molecules such as lipocalin-2 (percentage reduction; 9), TNF (19), CXCL10 (44), CD40 (32) and several other pro-inflammatory molecules which were upregulated in LPS-stimulated microglia. In addition, co-culture with MSC induced the expression of anti-inflammatory genes such as TGM2 (fold increase; 3), TGFß (3), TIMP (18) and IL1ra (12) compared to LPS-stimulated microglia. By using this non-conventional approach of microarray data analysis, we have obtained a snapshot view of the genes expressed by microglia in response to an inflammatory stimulus that are modulated by MSC. Keywords: Gene Expression, Immunomodulation, Mesenchymal Stem Cells, Microglia, Microarray Conference: 14th Meeting of the Asian-Pacific Society for Neurochemistry, Kuala Lumpur, Malaysia, 27 Aug - 30 Aug, 2016. Presentation Type: YIC06: Young Investigator Colloquium 6 Topic: 14th Meeting of the Asian-Pacific Society for Neurochemistry Citation: Jose S, Chan SC, Ling K, Veerakumarasivam A and Vidyadaran S (2016). Microarray profiling provides insights into mechanisms of mesenchymal stem cells-mediated immunomodulation of activated microglia. Conference Abstract: 14th Meeting of the Asian-Pacific Society for Neurochemistry. doi: 10.3389/conf.fncel.2016.36.00076 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 04 Aug 2016; Published Online: 11 Aug 2016. * Correspondence: Dr. Shinsmon Jose, Universiti Putra Malaysia, Neuroinflammation Group, Immunology Laboratory, Department of Pathology, Faculty of Medicine Health Sciences, Serdang, Selangor, Malaysia, josesn@ucmail.uc.edu Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Shinsmon Jose Soon C Chan King-Hwa Ling Abhi Veerakumarasivam Sharmili Vidyadaran Google Shinsmon Jose Soon C Chan King-Hwa Ling Abhi Veerakumarasivam Sharmili Vidyadaran Google Scholar Shinsmon Jose Soon C Chan King-Hwa Ling Abhi Veerakumarasivam Sharmili Vidyadaran PubMed Shinsmon Jose Soon C Chan King-Hwa Ling Abhi Veerakumarasivam Sharmili Vidyadaran Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Curcumin as an adjuvant to breast cancer treatment.

Cancer is the second largest leading cause of death worldwide and breast cancer is the most prevailing cause of mortality among all cases of malignant neoplastic disease in adult females. The incidence rate of breast malignant neoplastic disease is predominantly higher in Western women, when compared to women in Asian nations. The definitive reason for this conflict is even unknown, but dietary factors have been conceived to account for approximately 30% of cancers in Western nations. It has been hypothesized that ethnicity, including use of a variety of spices in the food would be a major reason. Among all spices, turmeric (Curcuma longa) has been proven for its better anticancer potential. In this review different molecular mechanisms including cell cycle arrest; G0/G1 and/or G2/M phase cell cycle arrest by up-regulating Cdk inhibitor, p21/WAF/CIPI and p53, inhibition of transcriptional factors; NFκB, AP-1, TNFα, IL, STAT-3, and PPAR-γ, downstream gene regulation; c-myc, Bcl-2, COX-2, NOS, Cyclin D1, TNFα, interleukins and MMP-9, growth factors; bFGF, EGF, GCSF, IL-8, PDGF, TGFα, TNF, VEGF and cell adhesion molecules; fibronectin, vitronectin, and collagen which are involved in angiogenesis and metastasis, alsothe effectiveness of curcumin, when given in combination with chemotherapeutics like cyclophosphamide, doxorubicin, mitomycin etc. in treating breast cancer have been reviewed.

Modified regimen of etanercept for tumor necrosis factor receptor associated periodic syndrome (TRAPS) like illness

TRAPS, an autosomal dominant autoinflammatory disorder occurs due to mutations of the TNFRSF1A gene. Mutation negative TRAPS (TRAPS like illness) is also known. Anti TNF molecules (etanercept) is the mainstay of therapy. A 11-year-old boy with a 5 year clinical profile indicative of a TRAPS like illness and with negative mutation studies is described. He has been followed up for nearly 2 years after starting etanercept. He had sustained response to etanercept which has subsequently been titrated (0.4 mg/kg subcutaneously every 23-24 days) to keep him symptom free. Mutation negative cases of TRAPS can be diagnosed with a high index of suspicion. Treatment with etanercept is expensive but possibly intervals between doses could be titrated to reduce cost.

Controlled human wood smoke exposure: oxidative stress, inflammation and microvascular function

BackgroundExposure to wood smoke is associated with respiratory symptoms, whereas knowledge on systemic effects is limited. We investigated effects on systemic inflammation, oxidative stress and microvascular function (MVF) after controlled wood smoke exposure.MethodsIn a randomised, double-blinded, cross-over study 20 non-smoking atopic subjects were exposed at rest to 14, 220, or 354 μg/m3 of particles from a well-burning modern wood stove for 3 h in a climate controlled chamber with 2 week intervals. We investigated the level of oxidatively damaged DNA, inflammatory markers and adhesion molecules before and 0, 6 and 20 h after exposure. Six h after exposure we measured MVF non-invasively by digital peripheral artery tonometry following arm ischemia.ResultsThe MVF score was unaltered after inhalation of clean air (1.58 ± 0.07; mean ± SEM), low (1.51 ± 0.07) or high (1.61 ± 0.09) concentrations of wood smoke particles in atopic subjects, whereas unexposed non-atopic subjects had higher score (1.91 ± 0.09). The level of oxidatively damaged DNA, mRNA of ITGAL, CCL2, TNF, IL6, IL8, HMOX1, and OGG1 and surface marker molecules ICAM1, ITGAL and L-selectin in peripheral blood mononuclear cells were not affected by inhalation of wood smoke particles.ConclusionsExposure to wood smoke had no effect on markers of oxidative stress, DNA damage, cell adhesion, cytokines or MVF in atopic subjects.

β-Arrestin-1 Protein Represses Diet-induced Obesity

Diet-related obesity is a major metabolic disorder. Excessive fat mass is associated with type 2 diabetes, hepatic steatosis, and arteriosclerosis. Dysregulation of lipid metabolism and adipose tissue function contributes to diet-induced obesity. Here, we report that β-arrestin-1 knock-out mice are susceptible to diet-induced obesity. Knock-out of the gene encoding β-arrestin-1 caused increased fat mass accumulation and decreased whole-body insulin sensitivity in mice fed a high-fat diet. In β-arrestin-1 knock-out mice, we observed disrupted food intake and energy expenditure and increased macrophage infiltration in white adipose tissue. At the molecular level, β-arrestin-1 deficiency affected the expression of many lipid metabolic genes and inflammatory genes in adipose tissue. Consistently, transgenic overexpression of β-arrestin-1 repressed diet-induced obesity and improved glucose tolerance and systemic insulin sensitivity. Thus, our findings reveal that β-arrestin-1 plays a role in metabolism regulation.

Threshold formation of an intermolecular charge transfer complex of a semiconducting polymer

It has been found that the formation of an intermolecular charge transfer complex in the ground electronic state between the model conjugated polymer (poly[2-methoxy-5-(2′-ethyl-hexyloxy)-1,4-phenylene vinylene] (MEH-PPV) and the low-molecular-weight organic acceptor (2,4,7-trinitrofluorenone, TNF) occurs stepwise with an increase in the acceptor concentration in the blend as is observed in the optical absorption spectra of solutions. The threshold dependence of the absorption of the charge transfer complex is attributed to the stepwise change in the concentration of the charge transfer complexes, which is not explained by the standard model describing the optical characteristics of intermolecular charge transfer complexes. A kinematic model has been proposed to explain the threshold increase in the concentration of charge transfer complexes: at low acceptor concentrations, the charge transfer complex is formed primarily on the surface of a polymer coil, whereas as the acceptor fraction in the solution increases, TNF molecules penetrate inside the polymer coils, forming the charge transfer complex with the units of the polymer inside the coil.

A potential role of TNFR gene polymorphisms in autoimmune thyroid diseases in the Tunisian population

Autoimmune thyroid diseases (AITDs) including Graves disease (GD) and autoimmune hypothyroidism (AH) are associated with TNF genes polymorphisms. TNF molecules bind to TNFRI and TNFRII. No genetic association was reported between TNFR and AITDs. In this study, we have analysed two polymorphisms in TNFRI gene (TNFRI+36A/G SNP and a microsatellite (GT)17 (GA)n) and one polymorphism in TNFRII gene (TNFRII +676 T/G). All these polymorphisms were studied in a large Tunisian family with high prevalence of AITDs, and on a case-control sample of 91 GD patients and 165 controls. The present study was undertaken to investigate the genetic association of these polymorphisms with AITDs development. We reported the implication of TNFRIA3 allele in AITDs pathogenesis in familial and case control studies, respectively (χ2=4.13, p=0.042; χ2=9.26, pc=0.005). In addition, Case-control study has revealed for the first time that TNFRII+676G allele was associated with GD (χ2=11.53; p=0.0007). Two TNFRI haplotypes were found to be associated with GD: TNFRI+36G-A8, TNFRI+36A-A3 (χ2=88.07; p=6.32×10−21, χ2=16.78; p=4.2×10−5, respectively). Our data showed that TNFRI polymorphisms have an important role in AITDs pathogenesis in both familial and case-control samples and that TNFRII was rather implicated in GD development in the Tunisian population.

Structure and Dynamics of a Discotic Liquid‐Crystalline Charge‐Transfer Complex

The structure of the charge-transfer complex hexakis(n-hexyloxy)triphenylene-2,4,7-trinitro-9-fluorenone (HAT6-TNF) has been characterized by neutron scattering, X-ray diffraction (XRD), optical microscopy, and dielectric relaxation spectroscopy (DRS). On the basis of these data and the 1:1 stoichiometry, a consistent structure for the complex is proposed. This structure differs markedly from structures previously proposed for similar materials, because the TNF molecules are found to be situated between the discotic columns rather than sandwiched between the discotic molecules of a given column. The addition of TNF to HAT6 is found to stiffen the structure, and quasi-elastic neutron scattering shows that the local dynamics of the discotic molecules in HAT6-TNF is slowed by the presence of the TNF molecules. This scenario is consistent with the observation of two VFT-type (VFT=Vogel-Fulcher-Tamman) dielectric relaxation processes that relate to the columnar glass transition and a polyethylene-like hindered glass transition originating from the nano-phase-separated fraction of the aliphatic tails.

MyD88-dependent changes in the pulmonary transcriptome after infection withChlamydia pneumoniae

Chlamydia pneumoniae, an intracellular bacterium, causes pneumonia in humans and mice. Toll-like receptors and the key adaptor molecule myeloid differentiation factor-88 (MyD88) play a critical role in inducing immunity against this microorganism and are crucial for survival. To explore the influence of MyD88 on induction of immune responses in vivo on a genome-wide level, wildtype (WT) or MyD88(-/-) mice were infected with C. pneumoniae on anesthesia, and the pulmonary transcriptome was analyzed 3 days later by microarrays. We found that the infection caused pulmonary cellular infiltration in WT but not MyD88(-/-) mice. Furthermore, it induced the transcription of 360 genes and repressed 18 genes in WT mice. Of these, 221 genes were not or weakly induced in lungs of MyD88(-/-) mice. This cluster contains primarily genes encoding for chemokines and cytokines like MIP-1alpha, MIP-2, MIP-1gamma, MCP-1, TNF, and KC and other immune effector molecules like immunoresponsive gene-1 and TLR2. Arginase was highly induced after C. pneumoniae infection and was MyD88 dependent. Genes induced by interferons were abundant in a cluster of 102 genes that were only partially MyD88 dependent. Also, lcn2 (lipocalin-2) and timp1 were represented within this cluster. Interestingly, a set of 37 genes including sprr1a was induced more strongly in MyD88(-/-) mice, and most of them are involved in the regulation of cellular replication. In summary, ex vivo analysis of the pulmonary transcriptome on infection with C. pneumoniae demonstrated a major impact of MyD88 on inflammatory responses but not on interferon-type responses and identified MyD88-independent genes involved in cellular replication.

Enhanced photo and thermal oxidative stability of the charge-transfer complexes of a conjugated polymer

The thermal oxidative stability of a conjugated polymer (CP) is very important for its processing and exploitation, while the photoand/or thermo-oxidation of polymers is a major factor that leads to shortening the lifetime and lowering the efficiency of various devices based on them.1,2 Therefore, the elucidation of mechanisms of such a degradation and correct service life predictions are necessary for optimising CP-based devices. Poly[2-methoxy-5-(2'-ethylhexyloxy)-1,4-phenylene vinylene] (MEH-PPV) is now a ‘classic’ model for tackling generic problems of CPs.3 It has been reported recently4 that MEH-PPV is capable of forming intermolecular charge-transfer complexes (CTCs) with small organic acceptors such as 2,4,7-trinitrofluorene-9-one (TNF). The drop-cast films of both pristine MEH-PPV (SigmaAldrich, MW = 125000) and MEH-PPV blends with TNF (Aldrich, mp 171, > 98% purity) were prepared from chlorobenzene by varying the polymer concentration in the range 0.5–2 g dm–3 and the TNF:MEH-PPV molar ratio in the range 0.01–1. The susceptibility of neat MEH-PPV to photo oxidation and a comparison with that of MEH-PPV/TNF blends is illustrated in Figure 1. An immediate blue shift of lmax and a progressive reduction of Amax were observed in the course of irradiation; this was explained by shortening the π-electron delocalization length of the polymer. The FTIR spectra of the same films measured before and after irradiation exhibited new bands at 1279 and 1691 cm–1 unambiguously indicating5 the photo oxidation of PPV. It is evident that MEH-PPV/TNF blends exhibit a markedly improved photo-oxidative stability as compared to that of the neat polymer. Moreover, for TNF contents increasing in the range 5– 25 mol%, the blends demonstrated a clear systematic gain in their thermal-oxidative stability. It is of importance that both of the blend components have revealed a synergistic behaviour in terms of the stability enhancement (Figure 2). Comparative experiments have shown that fullerene C60 is also capable of stabilizing MEH-PPV, but in much higher concentrations. Experimental data obtained by other methods indicate spectacular non-covalent interactions between the donor and the acceptor within the same (5–25 mol%) range of TNF contents. Partial electron density transfer from the MEH-PPV polymer onto TNF molecules involved in the corresponding CTC (according to FTIR and Raman data) should, in principle, reduce the susceptibility of the polymer to oxygen. It is likely that the quenching of the triplet states excited on the macromolecules can effectively prevent triplet–triplet annihilation reactions, which are normally feasible in the presence of reactive singlet oxygen.6 The kinetic studies of both MEH-PPV/TNF blends and the pristine polymer (using a model-free Friedman analysis, nonlinear regression analysis of the kinetic parameters,7 and lifetime prediction) has indicated that four-step thermal-oxidative degradation processes are operative in the system. The experimental results suggest that the complexed TNF (or the corresponding TNF/MEH-PPV charge-transfer complex) is capable 1.0

CYT-6091 (Aurimune): a colloidal gold-based tumor-targeted nanomedicine

Format This is a copy of the slides presented at the meeting but not formally written up for the volume. Abstract Targeting potent anti-cancer therapeutics to solid tumors is best accomplished by first avoiding recognition and uptake by the immune system and second by limiting the biodistribution of the drug to the tumor. We have achieved these objectives by binding tumor necrosis factor alpha (TNF) to the surface of 30 nm pegylated colloidal gold particles. Pegylation of the gold nanoparticles is accomplished by binding thiolated polyethylene glycol in between the TNF molecules on the surface of the gold nanoparticles. This formulation is termed CYT-6091 (Aurimune). The liver or spleen (the RES) take-up little or no drug 6 hr after CYT-6091 is injected into mice, and TNF levels in the tumors increase over this time period (in contrast to decreasing levels of TNF seen in healthy tissues). Electron micrographs also show gold nanoparticles in the tumors, but few or no particles in healthy tissue. By getting more TNF to the tumors, CYT-6091 is both safer and more effective in causing tumor regression in mice. CYT-6091 has also been given to dogs with naturally occurring cancers. Most notably in both dogs with cancer and in healthy rabbits, CYT-6091 caused fever, but did not induce hypotension. Historically, hypotension has been the dose-limiting toxicity for TNF and the primary reason for its failure in human clinical trials. For human testing, the manufacturing of CYT-6091 was successfully scaled-up and produced under cGMP. CYT-6091 is currently being tested in end-stage disease cancer patients in an NCI sponsored Phase I clinical trial.

Therapeutic modulation of signal transduction pathways.

Inflammatory bowel disease (IBD) is a chronic, relapsing inflammatory disorder of the gastrointestinal tract, which arises from inappropriate activation of the immune system. The inflammatory response is characterized by overproduction of immune cells, inflammatory cytokines, and tissue-destructive enzymes. IBD is treated with conventional (immunosuppressive) drugs and relatively new therapeutics, such as antiTNF. Anti-TNF medication targets and neutralizes TNF molecules, which are extra cellular mediators of inflammation. Available drugs lighten many of the symptoms of disease. However, they generally do not interfere with the underlying mechanisms, are relatively non-selective and have dose-limiting side effects. Disease relapse remains also a problem with current drug options. For these reasons, new therapeutic modalities are needed in the field of inflammatory pathology. In the last decade, much is learned about underlying pathogenic mechanisms of these diseases and this created new therapeutic options. As a result, attention has shifted toward modulation of intracellular signaling pathways for several chronic inflammatory disorders, such as psoriasis, asthma, pancreatitis, rheumatoid arthritis and IBD. There have been described many signaling pathways, that play a crucial role in inflammatory pathology. These intracellular signaling pathways connect the extracellular environment to the process of gene transcription. We distinguish two major pathways of transcription factor activation, which is shown in Figure 1. 1 The first group consists of latent cytoplasmic transcription factors, which are directly activated upon receptor-ligand interaction. The second group includes intracellular phophorylation cascades. These signaling cascades contain various protein kinases, which can activate downstream target molecules, such as transcription factors.

Heterotrimers Formed by Tumor Necrosis Factors of Different Species or Muteins

Incubation of murine tumor necrosis factor (mTNF) at subnanomolar concentrations results in partial dissociation of the trimers, coinciding with a decrease in bioactivity. Using size-exclusion chromatography, we observed that the conversion of labeled mTNF to monomers is not only prevented by coincubation with an excess of unlabeled mTNF but also with unlabeled human TNF (hTNF). Moreover, after coincubation of mTNF and hTNF four different TNF complexes were revealed by native polyacrylamide gel electrophoresis, viz. homotrimeric mTNF and hTNF, as well as two complexes with an intermediate migration pattern. Analytical gel filtration in combination with native polyacrylamide gel electrophoresis and Western blot immunodetection indicated that these new complexes consisted of heterotrimeric TNF molecules. We conclude that an exchange of monomers takes place during coincubation of two different species of TNF, which results in homotrimeric and heterotrimeric TNF. To assess receptor interaction in vitro, TNF heterotrimeric molecules were used as obtained after incubation of mTNF with labeled hTNF (which only binds to mTNF receptor I) or with labeled mutein mTNF75 (specific for mTNF receptor II). These heterotrimers were retained by both mTNF receptors, which means that the mTNF subunits incorporated in heterotrimeric complexes still can bind to both types of TNF receptor. In addition, the gradual decrease in mTNF bioactivity during preincubation at subnanomolar concentrations was prevented by the presence of mutein mTNF75, which is inactive in an L929 cytotoxicity assay, indicating that heterotrimerization can influence the overall bioactivity.

TNF? and the TNF receptor superfamily: Structure-function relationship(s)

Tumour Necrosis Factor alpha (TNF alpha), is an inflammatory cytokine produced by macrophages/monocytes during acute inflammation and is responsible for a diverse range of signalling events within cells, leading to necrosis or apoptosis. The protein is also important for resistance to infection and cancers. TNF alpha exerts many of its effects by binding, as a trimer, to either a 55 kDa cell membrane receptor termed TNFR-1 or a 75 kDa cell membrane receptor termed TNFR-2. Both these receptors belong to the so-called TNF receptor superfamily. The superfamily includes FAS, CD40, CD27, and RANK. The defining trait of these receptors is an extra cellular domain comprised of two to six repeats of cysteine rich motifs. Additionally, a number of structurally related "decoy receptors" exist that act to sequester TNF molecules, thereby rescuing cells from apoptosis. The crystal structures of TNF alpha, TNF beta, the extracellular domain of TNFR-1 (denoted sTNFR-1), and the TNF beta sTNFR-1 complex have been defined by crystallography. This article will review the structure/function relationships of the TNF alpha and the TNF receptor superfamily. It will also discuss insights as to how structural features play a role in the pleiotropic effects of TNF alpha.

TNF and related molecules: trends in neuroscience and clinical applications

A clear message to emerge from the recent 6th International TNF Congress is that TNF- α, LT- α and possibly other TNF family members, are important integral mediators of the CNS stress response to threatened homeostasis and that either excessive or insufficient TNF- α production can have significant consequences upon correct CNS functioning. Experimental data are particularly relevant in light of recent evidence which shows some linkage between polymorphisms in the human TNF- α/LT- α locus and susceptibility to CNS infection and thus highlight such cytokine pathways as promising therapeutic targets for the management of certain CNS diseases. Judging by the significant advances that have been made recently in the field of cytokine neurobiology, and the currently explosive development of transgenic and gene mutant mouse models with which to probe the cellular and molecular mechanisms of TNF- α and LT- α action within the CNS, we can look forward to shortly understanding more precisely the important and diverse roles that these cytokines play in CNS health and disease.

Lyotropic phase behaviour of disc-shaped tetra-palladium organyls in apolar organic solvents [1

Abstract The lyomesomorphic behaviour in apolar organic solvents of members of two series 1 and 2 of disc-shaped palladium organyls—the syntheses of four of them are new (1d, f and 2a, e) and are described here—each carrying twelve long lipophilic chains have been studied. Their lyomesomorphism appeared to be complex and has been observed here for the first time with metal organyls. As can be seen by polarizing microscopy, most of the binary mixtures investigated here exhibit nematic properties. For two members of series 1—the chloro-bridged 1b and its bromo-analogue 1c—there is even evidence for the existence of two different nematic lyomesophases side by side showing reversible transitions between them. In ternary systems, i.e. after the addition of 2,4,7-trinitrofluorenone (TNF, a strong electron acceptor), the nematic phases are stabilized, suggesting that their mesophase structures are made up by columns with intercalated TNF molecules (charge transfer complex formation). Influences of structural features of the pallado-mesogens on the one hand and of the type of solvent on the other on the molecular self-aggregation in the observed types of lyotropic mesophase formed are discussed in detail.

The role of tumor necrosis factor receptors in cell signaling and the significance of soluble form levels in the serum.

Two types of tumor necrosis factor membrane receptors (TNF-R) have been identified, namely 55 and 75 kDa TNF-R. Soluble forms of these receptors are present in the human serum. Recent findings on the role of these two TNF-R in biological cell signaling and the clinical significance of the serum levels of soluble TNF-R (sTNF-R) were reviewed. It is not the uptake of TNF molecules into cells but rather the molecular capping of TNF-R on the cell membrane that initiates the biological activity of TNF. The 55 kDa TNF-R mediates major bioactivities of TNF, while the significance of 75 kDa TNF-R remains unclear. We herein suggest a new concept of the role of these two TNF-R: The 75 kDa TNF-R signal appeared to enhance that of 55 kDa TNF-R in the induction of ICAM-1 expression on HL-60 human promyelocytic leukemic cells. High serum levels of sTNF-R are reported in patients with malignancy, endotoxin shock, pneumonia, and autoimmune diseases. However, the source of elevated serum sTNF-R remains unclear. Studies on the clinical usefulness of serum sTNF-R levels as cancer and inflammation markers are now being carried out.