Role Of TNF Research Articles

The Role of TNF- α Inhibitors in The Management of Gout Arthritis and Its Comparison with Other Modalities

Background: Gout arthritis is caused by the deposition of monosodium urate crystals in the joints, which can cause significant pain, swelling, and recurring inflammation, particularly in the big toe. Inflammatory mediators are critical to the beginning and duration of the inflammatory response in gout arthritis. Gout is mediated by TNF-α, ILs, and the NLRP3 inflammasome, which promotes macrophages, monocytes, and neutrophils, leading to inflammatory reactions. TNF-α acts as a potent inflammatory mediator by stimulating the expression of other inflammatory cytokines, adhesion molecules, and matrix metalloproteinases (MMPs). TNF-α interacts with particular receptors and activates intracellular signaling pathways, leading to leukocyte recruitment, NLRP3 inflammasome activation, and the release of other inflammatory mediators. Objective: This article is a review article in which the researchers examine the current state of understanding regarding the role of TNF-α as a major inflammatory mediator in gout arthritis, deepen the understanding of TNF-α in gout inflammation, and explore its potential as a therapeutic target. Method: It involvedsystematically searching relevant databases, selecting studies based on inclusion criteria, and synthesizing findings to identify trends, gaps, and the current state of knowledge on the topic. Result: The results of this review article indicated that TNF-α plays a crucial role in joint inflammation by triggering the release of pro-inflammatory cytokines and stimulating neutrophil infiltration into the joints. Conclusion: Thus, Inhibiting TNF-α can reduce inflammation and improve symptoms in people with gout arthritis.

Differential regulation of natural killer cells by tumor necrosis factor receptors 1 and 2

Abstract Tumor necrosis factor (TNF) is a key cytokine across homeostasis, health, and disease. However, the role of TNF is often dichotomous in that it is critical for protective anti-microbial and anti-tumour responses, yet it is also a major player in immune dysfunction and immune-related pathology. Surprisingly, while the effects of TNF on myeloid responses are well studied, how TNF impacts lymphocyte responses is yet to be elucidated. This is particularly the case for natural killer (NK) cells, innate lymphoid cells which play a key role in immune protection against both cancer and infection. To address this knowledge gap, we have generated novel transgenic mouse models which lack the receptors for TNF (TNFR1 and/or TNFR2) specifically on NK cells, allowing us to precisely dissect how TNF directly regulates NK cell function and survival, along with the relative importance of each receptor. Using single cell RNA sequencing among other techniques, we have discovered TNF regulates expression of co-inhibitory receptors on NK cells, including Tim3 and TIGIT, through both TNFR1 and TNFR2. In models of infection and cancer we have found that TNFR1 plays an inhibitory role through depletion of NK cells, leading to increased disease burden. Conversely, TNFR2 plays a protective role through maintenance of optimal NK function and cytokine production, promoting disease control. This ongoing work establishes the importance of TNF in the regulation of NK cell function, which could have significant clinical implications.

Impact of Vitamin C on Gene Expression Profile of Inflammatory and Anti-Inflammatory Cytokines in the Male Partners of Couples with Recurrent Pregnancy Loss

Immune system disorders and increased inflammation in the male reproductive system can lead to fetal risk in the early stages of development and implantation. Antioxidants such as vitamin C can play a protective role against sperm inflammatory reactions. This study aimed to evaluate the effect of vitamin C on the expression of inflammatory and anti-inflammatory cytokine genes in the male partners of couples with recurrent pregnancy loss. In this randomized clinical trial, twenty male partners of couples with RPL were examined for sperm parameters and expression profile of some inflammatory and anti-inflammatory cytokine genes before and after treatment with vitamin C. There was a statistically significant higher rate of normal morphology and sperm concentration in each patient before and after treatment with vitamin C (p ≤ 0.05). The mRNA levels of interleukin 6 and tumor necrosis factor-alpha were significantly decreased in the sperm of patients after treatment with vitamin C compared to before treatment. In contrast, the gene expression levels of interleukin 4 and transforming growth factor-beta showed a significant increase in the sperm of patients after treatment with vitamin C. Oral daily administration of vitamin C may be effective in the fertility potential of male partners of couples with RPL not only through the improvement of the sperm parameters but also by modulating the expression profile of inflammatory and anti-inflammatory genes. Further studies on protein levels are needed to clarify the role of TNF-⍺ and IFN-γ as a prognostic value in evaluating the recurrent abortion risk in infertile male partners. This trial is registered with IRCT20180312039059N1.

Investigation of the effect of TNF-α on damage to retinal pigment epithelial cells in age-related macular degeneration

Oxidative stress alters cellular homeostasis and elicits a cellular response that depends on the severity and type of damage: some cells activate defense mechanisms designed to ensure survival; the other, provided that the defense mechanisms are inhibited, triggers alternative signaling pathways that lead to apoptosis, necrosis, pyroptosis, autophagy, and so on. However, the exact cause of such damage and induction of oxidative stress, including the associated oxidative effects around pigment epithelial cells in the context of the onset and progression of age-related macular degeneration – one of the world’s most common eye diseases with blindness, remains unclear. Therefore, in the course of the study we turned to key biogenetic points of regulation of inflammation and apoptosis, in particular TNF. The aim of the work is to shed light on the role of TNF as a genetic determinant that can initiate and influence the course of age-related macular degeneration. For this purpose, the main pathognomonic markers of the morphological structure of the macula were determined in 291 persons with age-related macular degeneration and in 105 persons without ophthalmic pathology, using optical coherence tomography to confirm or exclude the diagnosis of the disease. To detect polymorphism of the TNF gene, we used the method of real-time PCR diagnostics on the BioRad CFX 96 amplifier using LiTech reagents. Statistical processing of the results was performed using Hardy-Weinberg equilibrium, Kruskal-Wallis method, logistic regression analysis and construction of the ROC curve to determine the AUC range and sensitivity and specificity values. The study revealed a significant difference in the distribution of mutant genotypes between patients with both forms of AMD and the control group. There was also a statistically significant effect of mutant allele A on the development of both "dry" (OR = 3.40; 95.0 %; CI = 1.90-6.07, p<0.001) and "wet" form of AMD (OR = 4.78; 95.0 % CI 2.65-8.64, p<0.001), and in the analysis of mutant genotypes it was found that the GA genotype increases the chances of "dry" and "wet" forms of the disease by 3.13 and 4.74 times, respectively, while AA – 5 times, regardless of the form of the disease. confirms the influence of TNF gene polymorphism on the occurrence and progression of age-related macular degeneration. In the analysis of ROC-curves and AUC regions, it was found that all mutant genotypes have a significant effect on the occurrence of age-related macular degeneration (p<0.05). However, the obtained values of sensitivity and specificity, especially in the AA genotype in both "dry" (17.9 % and 95.8 %, respectively) and "wet" (18.2 % and 95.8 %, respectively) forms of age-related macular degeneration indicate a low chance of error-free confirmation of the diagnosis. a disease that may be associated with multifactorial disease and requires further research.

Role of TNF-α in Periodontal Disease & Its Implication on Systemic Health

Periodontal disease is a polymicrobial infection, characterized by gingival inflammation, pocket formation, loss of connective tissue attachment and supporting alveolar bone. Though the etiology of periodontal disease has been established and micro-organisms have been implicated, pathology of these inflammatory lesions have been attributed not only to bacterial products, that have adverse effects on the tissues, but also to chemical mediators released by the host cells, as a result of inflammatory and immune reactions. Oral micro- organisms trigger the endogenous pathways of tissue degradation by activating host cells to produce and release inflammatory mediators and cytokines. These inflammatory mediators and cytokines manifest potent pro-inflammatory and catabolic activity and may play a key role in local amplification of the immune response as well as in periodontal tissue breakdown Apart from playing an important role in periodontal destruction, systemic elevation of TNF –  levels is extremely toxic to the host and hence has been termed as the “Suicide hormone”. TNF – , has been postulated to mediate wasting during chronic infections. This review aims to explore the role of TNF –  in periodontal disease & its implication on systemic health.

Current Perspectives on the Role of TNF inHematopoiesis Using Mice With Humanization of TNF/LT System.

TNF is a multifunctional cytokine with its key functions attributed to inflammation, secondary lymphoid tissue organogenesis and immune regulation. However, it is also a physiological regulator of hematopoiesis and is involved in development and homeostatic maintenance of various organs and tissues. Somewhat unexpectedly, the most important practical application of TNF biology in medicine is anti-TNF therapy in several autoimmune diseases. With increased number of patients undergoing treatment with TNF inhibitors and concerns regarding possible adverse effects of systemic cytokine blockade, the interest in using humanized mouse models to study the efficacy and safety of TNF-targeting biologics in vivo is justified. This Perspective discusses the main functions of TNF and its two receptors, TNFR1 and TNFR2, in steady state, as well as in emergency hematopoiesis. It also provides a comparative overview of existing mouse lines with humanization of TNF/TNFR system. These genetically engineered mice allow us to study TNF signaling cascades in the hematopoietic compartment in the context of various experimental disease models and for evaluating the effects of various human TNF inhibitors on hematopoiesis and other physiological processes.

TNF-Alpha Serum Level as Prognostic Factor in Pediatric Sepsis Patients

OBJECTIVE: The study aimed to investigate the role of TNFα-308 genetic polymorphism, association between TNF-α serum level and prognostic factor of mortality in pediatric sepsis. 
 
 METHODS: This was a prospective cohort study. Consecutive sampling method was used and samples were obtained from septic patients diagnosed based on the IPSC 2005 criteria. Serum TNF-α and genetic polymorphism were measuread and analyzed with ELISA and PCR plus sequencing, respectively.
 
 RESULT: One hundred and seventeen samples were included, 62 were in survivor grioup and 55 in non survivor group. A very significant association was found between TNF-α serum level and mortality (p<0.001). The optimal cut off point of TNFα serum level as prognostic factor for mortality was ≥ 500 pg/mL (p<0.001 and OR 16.6) sensitivity 78.1%, specificity 82%, Positive Predictive Value (PPV) 79.6%, Negative Predictive Value (NPV) 80.9%, Area Under Curve (AUC) 0.811. Two samples showed TNFα-308A polymorphism and mutation of GG allele to heterozygote GA allele. Neither TNFα polymorphism and TNFα serum level showed any association with mortality. There was no significant association between TNFα-308 polymorphism and TNF-α serum level p=0.461(p>0.05) and mortality p=0.219 (p>0.05), all sample who had TNFα-308 genetic polymorphism were in non survivor group and had TNF-α serum level ≥ 500 pg/mL. 
 
 CONCLUSION: Genetic polymorphism of TNF-α-308 showed no statistic significant on mortality, but all subjects with TNFα-308 polymorphism had higher TNF-α serum and were all in non-survivor group.

Abstract P430: Inflammatory Survival Gene Expression Patterns Differentiate Favorable and Unfavorable Outcomes Following Surgical Intervention in Intracerebral Hemorrhage

Background and Aims: Surgical management of intracerebral (ICH) remains controversial due to unclear benefit. In this study, we analyzed temporal changes in expression of proinflammatory and anti-inflammatory survival genes to discern the molecular differences between favorable and unfavorable outcomes after surgery. Methods: Venous blood collected in Paxgene Blood RNA from ICH patients before surgery at ‘early’ (Day 0-2) and at ‘delayed’ (Day 3-5) timepoints. Extracted total RNA was used for real-time Taqman PCR analysis for anti-inflammatory, survival genes superoxide dismutase 1(SOD1), COX-2, IL-10, peroxisome proliferator activated receptor gamma (PPARG), TGF-B1, and IL-10. The pro-inflammatory genes included arginase-1 (ARG1), TNF, IL-1B, monocyte/macrophage activity markers (CD36, CD163) and NF-kB members (NFKB1, NFKB2, RELA, RELB, REL, NFKBIA). Relative fold changes were determined after normalizing to GAPDH. 90-day Modified Rankin Score (mRS) were collected and classified as favorable, mRS 0-3 (n=4) and unfavorable, mRS 4-6 (n=8). Statistical analysis was carried out by Welch’s ANOVA test (p<0.05). Results: Mean age was 56.25yrs (SD 19.7). ICH location was 10 deep nuclei (thalamus or basal ganglia), 1 cerebellum, and 1 lobar. ICH volume was lower in the mRS 0-3 group (24.15ml SD21.2 vs 35.8ml SD 31.7 p=0.68). All patients had a decompressive hemicraniectomy and 7 included hematoma evacuation. Overall, the NFkB family gene expression was increased at ‘delayed’ relative to the early time points in both groups. However, RELB expression was significantly higher at the early time point of mRS 0-3 compared to mRS 4-6 group. Expression of ARG1, SOD1, COX2, IL-1B, IL-10, TGF-B1, PPARG and CD36 increased significantly at the delayed compared to the early time point. In the unfavorable outcome group (mRS 4-6), TNF expression increased significantly at the delayed timepoints compared to mRS 0-3 which was unchanged. Conclusions: The studied genes were highly expressed and differed significantly between time points. TNF was significantly expressed at the delayed time point in the mRS 4-6 group but unchanged in the mRS 0-3 group. Further studies will explore the role of TNF and related genes in patient selection and outcomes for surgical management of ICH.

Functional impact of allelic variations/haplotypes of TNF-\u03b1 on reproductive tract infections in Indian women

The aim of the present study is to investigate the functional role of TNF-α single-nucleotide polymorphisms/haplotypes in an association with reproductive tract infections (RTIs) in symptomatic and asymptomatic women. A total of 850 consecutive subjects consisting of 400 cases and 450 healthy controls, were screened for RTIs, along with their risk factors and associated symptoms. The propensity score matching was performed to reduce the confounding bias arise owing to covariates and to balance the data between two groups. A total of 211 pairs (1:1) have been created. Genotyping of rs1800629 (-308) and rs361525 (-238) SNPs of TNF-α was done by PCR–RFLP followed by sequencing. The functional implication of TNF-α SNPs in an association with RTIs was also checked by using ELISA. The frequency of -238A allele and -308A allele was found to be twofold (P < 0.0001) and threefold (P < 0.0001) higher in the presence of RTIs. AA haplotype emerged as a major player in an association with RTIs and elevated TNF-α expression. The present study revealed the functional role of rs1800629 (-308) and rs361525 (-238) of TNF-α in an association with RTIs. This information may be used to establish biomarkers for an inflammatory response during the persistence of RTIs.

Mating induces early transcriptional response in the rat endosalpinx: the role of TNF and RA.

During mating, males provide not only the spermatozoa to fertilize the oocyte but also other stimuli that are essential for initiating and maintaining the reproductive programme in females. In the mammalian oviduct, mating regulates sperm storage, egg transport, fertilization, early embryonic development, and oestradiol metabolism. However, the main molecules underlying these processes are poorly understood. Using microarray analyses, we identified 58 genes that were either induced or repressed by mating in the endosalpinx at 3 h post-stimulus. RT-qPCR confirmed that mating downregulated the expression of the Oas1h and Prim1 genes and upregulated the expression of the Ceacam1, Chad, Chst10, Slc5a3 and Slc26a4 genes. The functional category 'cell-to-cell signalling and interaction' was over-represented in this gene list. Network modelling identified TNF and all-trans retinoic acid (RA) as upstream regulators of the mating-induced transcriptional response, which was confirmed by intraoviductal injection of TNF or RA in unmated rats. It partially mimicked the transcriptional effect of mating in the rat endosalpinx. Furthermore, mating decreased RA levels in oviductal fluid, and RA-receptor-gamma (RARG) exhibited a nuclear location in oviductal epithelium in both unmated and mated rats, indicating RA-RARG transcriptional activity. In conclusion, the early transcriptional response regulated by mating in the rat endosalpinx is mediated by TNF and RA. These signalling molecules regulate a cohort of genes involved in 'cell-to-cell signalling and interactions' and merit further studies to understand the specific processes activated in the endosalpinx to sustain the events that occur in the mammalian oviduct early after mating.

Effects of tumour necrosis factor on cardiovascular disease and cancer: A two-sample Mendelian randomization study.

BackgroundTumour necrosis factor (TNF) inhibitors are used in the treatment of certain autoimmune diseases but given the role of TNF in tumour biology and atherosclerosis, such therapies may influence the risk of cancer and cardiovascular disease. We conducted a Mendelian randomization study to explore whether TNF levels are causally related to cardiovascular disease and cancer.MethodsSingle-nucleotide polymorphisms associated with TNF levels at genome-wide significance were identified from a genome-wide association study of 30 912 European-ancestry individuals. Three TNF-associated single-nucleotide polymorphisms associated with higher risk of autoimmune diseases were used as instrumental variables. Summary-level data for 14 cardiovascular diseases, overall cancer and 14 site-specific cancers were obtained from UK Biobank and consortia.FindingsGenetically-predicted TNF levels were positively associated with coronary artery disease (odds ratio (OR) 2.25; 95% confidence interval (CI) 1.50, 3.37) and ischaemic stroke (OR 2.27; 95% CI 1.50, 3.43), and inversely associated with overall cancer (OR 0.54; 95% CI 0.42, 0.69), breast cancer (OR 0.51; 95% CI 0.39, 0.67), and colorectal cancer (OR 0.20; 95% CI 0.09, 0.45). There were suggestive associations of TNF with venous thromboembolism (OR 2.18; 95% CI 1.32, 3.59), endometrial cancer (OR 0.25; 95% CI 0.07, 0.94), and lung cancer (OR 0.45; 95% CI 0.21, 0.94).InterpretationThis study found evidence of causal associations of increased TNF levels with higher risk of common cardiovascular diseases and lower risk of overall and certain cancers.

The mechanism of the effects of Monascus jmbA rice on increased platelet count in Wistar rats infected with Dengue virus serotype 3.

BackgroundSeveral traditional medicines have been developed among communities as part of the efforts to improve thrombocytopenia in patients with Dengue virus infection (DVI). Among those efforts is the administration of Monascus jmbA rice (MJR), which is rice fermented with Monascus purpureus. The administration of MJR is believed to increase the platelet count in patients with DVI.AimThe objective of this study is to elucidate the mechanism of the effects of MJR on increased levels of platelets in DVI serotype 3 through changes in IL-3, IL-6, IL-11 and TNF-α.MethodsIt was a true experimental laboratory study using the randomized posttest only control group design. The study compared between groups of wistar rats were being treated only with group IVD wistar rats who experienced treatment followed by administration of MJR as well as groups of wistar rats without any treatment as a control group.ResultsThe increase in platelet count in the group treated with DVI + MJR was higher than that treated with only DVI and the difference was a significant (P<0.05). Increased levels of TNF-α in the group treated with DVI + MJR were lower than that treated with only DVI and the difference was significant (P<0.05). The significant levels of the causal relationship of TNF-α with IL-6, TNF-α with IL-11 and IL- 6 with platelets were 0.044 (P<0.05), 0.029 (P<0.05) and 0.041 (P<0.05), respectively.ConclusionMJR is capable of increasing platelet count through the role of TNF- α and IL-6 in Wistar rats infected with DVI serotype 3.

Assessment of the Microbiome Role in Skin Protection Against UV Irradiation Via Network Analysis.

Introduction: Diverse microbiotas which have some contributions to gene expression reside in human skin. To identify the protective role of the skin microbiome against UV exposure, proteinprotein interaction (PPI) network analysis is used to assessment gene expression alteration. Methods: A microarray dataset, GEO accession number GSE117359, was considered in this respect. Differential expressed genes (DEGs) in the germ-free (GF) and specific pathogen-free (SPF) groups are analyzed by GEO2R. The top significant DEGs were assigned for network analysis via Cytoscape 3.7.2 and its applications. Results: A total of 28 genes were identified as significant DEGs and the centrality analysis of the network indicated that only one of the seven hub-bottlenecks was from queried genes. The gene ontology analysis of Il6, Cxcl2, Cxcl1, TNF, Il10, Cxcl10, and Mmp9 showed that the crucial genes were highly enriched in the immune system. Conclusion: The skin microbiome plays a significant role in the protection of skin against UV irradiation and the role of TNF and IL6 is prominent in this regard.

A 3\u2032UTR modification of the TNF-\u03b1 mouse gene increases peripheral TNF-\u03b1 and modulates the Alzheimer-like phenotype in 5XFAD mice

Tumor necrosis factor-α (TNF-α) is a pro-inflammatory cytokine, involved in Alzheimer’s disease pathogenesis. Anti-TNF-α therapeutic approaches currently used in autoimmune diseases have been proposed as a therapeutic strategy in AD. We have previously examined the role of TNF-α and anti-TNF-α drugs in AD, using 5XFAD mice, and we have found a significant role for peripheral TNF-α in brain inflammation. Here we investigated the role of mouse TNF-α on the AD-like phenotype of 5XFAD mice using a knock-in mouse with deletion of the 3’UTR of the endogenous TNF-α (TNFΔARE/+) that develops rheumatoid arthritis and Crohn’s disease. 5XFAD/TNFΔARE/+ mice showed significantly decreased amyloid deposition. Interestingly, microglia but not astrocytes were activated in 5XFAD/ TNFΔARE/+ brains. This microglial activation was associated with increased infiltrating peripheral leukocytes and perivascular macrophages and synaptic degeneration. APP levels and APP processing enzymes involved in Aβ production remained unchanged, suggesting that the reduced amyloid burden can be attributed to the increased microglial and perivascular macrophage activation caused by TNF-α. Peripheral TNF-α levels were increased while brain TNF-α remained the same. These data provide further evidence for peripheral TNF-α as a mediator of inflammation between the periphery and the brain.

Innate Immune Functions of Astrocytes are Dependent Upon Tumor Necrosis Factor-Alpha

Acute inflammation is a key feature of innate immunity that initiates clearance and repair in infected or damaged tissues. Alternatively, chronic inflammation is implicated in numerous disease processes. The contribution of neuroinflammation to the pathogenesis of neurological conditions, including infection, traumatic brain injury, and neurodegenerative diseases, has become increasingly evident. Potential drivers of such neuroinflammation include toll-like receptors (TLRs). TLRs confer a wide array of functions on different cell types in the central nervous system (CNS). Importantly, how TLR activation affects astrocyte functioning is unclear. In the present study, we examined the role of TLR2/4 signaling on various astrocyte functions (i.e., proliferation, pro-inflammatory mediator production, regulatory mechanisms, etc) by stimulating astrocytes with potent exogenous TLR2/4 agonist, bacterial lipopolysaccharide (LPS). Newborn astrocytes were derived from WT, Tnfα−/−, Il1α−/−/Il1β−/−, and Tlr2−/−/Tlr4−/− mice as well as Sprague Dawley rats for all in vitro studies. LPS activated mRNA expression of different pro-inflammatory cytokines and chemokines in time- and concentration-dependent manners, and upregulated the proliferation of astrocytes based on increased 3H-thymidine update. Following LPS-mediated TLR2/4 activation, TNF-α and IL-1β self-regulated and modulated the expression of pro-inflammatory cytokines and chemokines. Polyclonal antibodies against TNF-α suppressed TLR2/4-mediated upregulation of astrocyte proliferation, supporting an autocrine/paracrine role of TNF-α on astrocyte proliferation. Astrocytes perform classical innate immune functions, which contradict the current paradigm that microglia are the main immune effector cells of the CNS. TNF-α plays a pivotal role in the LPS-upregulated astrocyte activation and proliferation, supporting their critical roles in in CNS pathogenesis.

Influence of inflammatory conditions provided by macrophages on osteogenic ability of mesenchymal stem cells

BackgroundThe mechanisms by which macrophage phenotype contributes to mesenchymal stem cells (MSC)-mediated bone repair remain unclear. In this work, we investigated the influence of factors released by human macrophages polarized to a pro-inflammatory or an anti-inflammatory phenotype on the ability of human MSC to attach, migrate, and differentiate toward the osteoblastic lineage. We focused on the role of TNF-α and IL-10, key pro-inflammatory and anti-inflammatory cytokines, respectively, in regulating MSC functions.MethodsMSC were treated with media conditioned by pro-inflammatory or anti-inflammatory macrophages to study their influence in cell attachment, migration, and osteogenic differentiation. The involvement of TNF-α and IL-10 in the regulation of MSC functions was investigated using neutralizing antibodies and recombinant cytokines.ResultsTreatment of MSC with media conditioned by pro-inflammatory or anti-inflammatory macrophages promoted cell elongation and enhanced MSC ability to attach and migrate. These effects were more noticeable when MSC were treated with media from pro-inflammatory macrophages. Interestingly, MSC osteogenic activity was enhanced by factors released by anti-inflammatory macrophages, but not by pro-inflammatory macrophages. Significant IL-10 levels originated from anti-inflammatory macrophages enhanced MSC osteogenesis by increasing ALP activity and mineralization in MSC layers cultured under osteogenic conditions. Moreover, macrophage-derived IL-10 regulated the expression of the osteogenic markers RUNX2, COL1A1, and ALPL. Notably, low TNF-α levels secreted by anti-inflammatory macrophages increased ALP activity in differentiating MSC whereas high TNF-α levels produced by pro-inflammatory macrophages had no effects on osteogenesis. Experiments in which MSC were treated with cytokines revealed that IL-10 was more effective in promoting matrix maturation and mineralization than TNF-α.ConclusionsFactors secreted by pro-inflammatory macrophages substantially increased MSC attachment and migration whereas those released by anti-inflammatory macrophages enhanced MSC osteogenic activity as well as cell migration. IL-10 was identified as an important cytokine secreted by anti-inflammatory macrophages that potentiates MSC osteogenesis. Our findings provide novel insights into how environments provided by macrophages regulate MSC osteogenesis, which may be helpful to develop strategies to enhance bone regeneration.

Sensory Ganglia-Specific TNF Expression Is Associated With Persistent Nociception After Resolution of Inflammation.

Joint pain is a distressing symptom of arthritis, and it is frequently persistent even after treatments which reduce local inflammation. Continuous production of algogenic factors activate/sensitize nociceptors in the joint structures and contribute to persistent pain, a challenging and difficult condition to treat. TNF is a crucial cytokine for the pathogenesis of several rheumatic diseases, and its inhibition is a mainstay of treatment to control joint symptoms, including pain. Here, we sought to investigate the inflammatory changes and the role of TNF in dorsal root ganglia (DRG) during persistent hypernociception after the resolution of acute joint inflammation. Using a model of antigen-induced arthritis, the peak of joint inflammation occurred 12–24 h after local antigen injection and was characterized by an intense influx of neutrophils, pro-inflammatory cytokine production, and joint damage. We found that inflammatory parameters in the joint returned to basal levels between 6 and 8 days after antigen-challenge, characterizing the resolving phase of joint inflammation. Mechanical hyperalgesia was persistent up to 14 days after joint insult. The persistent nociception was associated with the inflammatory status of DRG after cessation of acute joint inflammation. The late state of neuroinflammation in the ipsilateral side was evidenced by gene expression of TNF, TNFR2, IL-6, IL-1β, CXCL2, COX2, and iNOS in lumbar DRG (L3-L5) and leukocyte adhesion in the lumbar intumescent vessels between days 6 and 8. Moreover, there were signs of resident macrophage activation in DRG, as evidenced by an increase in Iba1-positive cells. Intrathecal or systemic injection of etanercept, an agent clinically utilized for TNF neutralization, at day 7 post arthritis induction, alleviated the persistent joint hyperalgesia by specific action in DRG. Our data suggest that neuroinflammation in DRG after the resolution of acute joint inflammation drives continuous neural sensitization resulting in persistent joint nociception in a TNF-dependent mechanism.

Immunoregulatory potential of mesenchymal stem cells following activation by macrophage-derived soluble factors

BackgroundImmunoregulatory capacity of mesenchymal stem cells (MSC) is triggered by the inflammatory environment, which changes during tissue repair. Macrophages are essential in mediating the inflammatory response after injury and can adopt a range of functional phenotypes, exhibiting pro-inflammatory and anti-inflammatory activities. An accurate characterization of MSC activation by the inflammatory milieu is needed for improving the efficacy of regenerative therapies. In this work, we investigated the immunomodulatory functions of MSC primed with factors secreted from macrophages polarized toward a pro-inflammatory or an anti-inflammatory phenotype. We focused on the role of TNF-α and IL-10, prototypic pro-inflammatory and anti-inflammatory cytokines, respectively, as priming factors for MSC.MethodsSecretion of immunoregulatory mediators from human MSC primed with media conditioned by human macrophages polarized toward a pro-inflammatory or an anti-inflammatory phenotype was determined. Immunomodulatory potential of primed MSC on polarized macrophages was studied using indirect co-cultures. Involvement of TNF-α and IL-10 in priming MSC and of PGE2 in MSC-mediated immunomodulation was investigated employing neutralizing antibodies. Collagen hydrogels were used to study MSC and macrophages interactions in a more physiological environment.ResultsPriming MSC with media conditioned by pro-inflammatory or anti-inflammatory macrophages enhanced their immunomodulatory potential through increased PGE2 secretion. We identified the pro-inflammatory cytokine TNF-α as a priming factor for MSC. Notably, the anti-inflammatory IL-10, mainly produced by pro-resolving macrophages, potentiated the priming effect of TNF-α. Collagen hydrogels acted as instructive microenvironments for MSC and macrophages functions and their crosstalk. Culturing macrophages on hydrogels stimulated anti-inflammatory versus pro-inflammatory cytokine secretion. Encapsulation of MSC within hydrogels increased PGE2 secretion and potentiated immunomodulation on macrophages, attenuating macrophage pro-inflammatory state and sustaining anti-inflammatory activation. Priming with inflammatory factors conferred to MSC loaded in hydrogels greater immunomodulatory potential, promoting anti-inflammatory activity of macrophages.ConclusionsFactors secreted by pro-inflammatory and anti-inflammatory macrophages activated the immunomodulatory potential of MSC. This was partially attributed to the priming effect of TNF-α and IL-10. Immunoregulatory functions of primed MSC were enhanced after encapsulation in hydrogels. These findings may provide insight into novel strategies to enhance MSC immunoregulatory potency.

TNF-\u03b1 enhances Th9 cell differentiation and antitumor immunity via TNFR2-dependent pathways

Tumor specific Th9 cells are potential effector cells for adoptive therapy of human cancers. TNF family members OX40L, TL1A and GITRL have been shown to promote the induction of Th9 cells and antitumor immunity. However, the role of TNF-α, the prototype of the TNF superfamily cytokines, in Th9 cell differentiation and their antitumor efficacy is not defined. Here, we showed that TNF-α potently promoted naïve CD4+ T cells to differentiate into Th9 cells in vitro. Furthermore, the addition of TNF-α during Th9 cell differentiation increased T cell survival and proliferation. More importantly, the adoptive transfer of TNF-α-treated Th9 cells induced more potent antitumor effects than regular Th9 cells in mouse tumor model. TNF-α signals via two cell surface receptors, TNFR1 and TNFR2. Mechanistic studies revealed that TNF-α drove Th9 cell differentiation through TNFR2 but not TNFR1. In addition, under Th9 polarizing condition, TNF-α activated STAT5 and NF-κB pathways in T cells in a TNFR2-dependent manner. Inhibition of STAT5 and NF-κB pathways by their specific inhibitors impaired TNF-α-induced Th9 cell differentiation. Our results identified TNF-α as a new powerful inducer of Th9 cells and clarified the molecular mechanisms underlying TNF-α-induced Th9 cell differentiation.

Involvement of tumor necrosis factor alpha in steroid-associated osteonecrosis of the femoral head: friend or foe?

BackgroundThe etiology and pathology osteonecrosis of the femoral head (ONFH) are not completely clarified. As a cytokine participating in systemic inflammation, tumor necrosis factor alpha (TNFα) has been shown to be involved in the pathogenesis of ONFH. However, the role of TNFα in ONFH is not clearly clarified. In the present study, we investigated the effects of TNFα on proliferation, angiogenesis, and osteogenic differentiation of rat bone mesenchymal stem cells (rMSCs) and the underlying mechanisms.MethodsAll femoral bone tissues were separated in surgeries. After extracting total RNA and protein, we evaluated TNFα content by ELISA and the relative expression levels of genes by quantitative real-time PCR and western blot. Also, immunohistochemistry staining was performed to observe the expression of Runx2 in the bone samples. Chick embryo chorioallantoic membrane (CAM) assay was performed to observe the effect of TNFα on angiogenesis. The genomic DNAs were treated by bisulfite modification, and methylation status of CpG sites in the CpG islands of human and rat Runx2 gene promoter was determined by DNA sequencing. The binding of H3K4me3 and H3K27me3 in Runx2 promoter was checked by ChIP assay. RNA-seq analysis was used to find out the genes and pathways changed by TNFα in rMSCs.ResultsThe results demonstrate TNFα promotes cell proliferation and angiogenesis whereas inhibits osteogenesis. Epigenetic regulations including DNA methylation and histone modifications play important roles in mediating the effect of TNFα on osteogenic differentiation. We find an increased rate of CpG methylation in rat Runx2 promoter in TNFα-treated rMSCs, as well as significantly increased occupancy of H3K27me3 in Runx2 gene promoter. The content of TNFα in necrotic tissue is much lower than that of normal tissue. And relevantly, human Runx2 promoter is demethylated in necrotic tissue using bone samples from patient with ONFH. In addition, we have observed that Wnt signaling pathway is inhibited by TNFα as multiple Wnts are markedly decreased in TNFα-treated rMSCs by RNA-seq analysis.ConclusionTaken together, our study shows that TNFα plays complicated roles in the pathogenesis of ONFH, including proliferation, angiogenesis, and osteogenesis. Targeting TNFα should not be considered as an applicable strategy to inhibit the progression of ONFH.