TNFR1 Signaling Research Articles

Tumor Necrosis Factor Alpha in Amyotrophic Lateral Sclerosis: Friend or Foe?

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease characterized by a massive neuroinflammatory reaction, which plays a key role in the progression of the disease. One of the major mediators of the inflammatory response is the pleiotropic cytokine tumor necrosis factor α (TNFα), mainly released within the central nervous system (CNS) by reactive astrocytes and microglia. Increased levels of TNFα and its receptors (TNFR1 and TNFR2) have been described in plasma, serum, cerebrospinal fluid and CNS tissue from both ALS patients and transgenic animal models of disease. However, the precise role exerted by TNFα in the context of ALS is still highly controversial, since both protective and detrimental functions have been reported. These opposing actions depend on multiple factors, among which includes the type of TNFα receptor activated. In fact, TNFR2 seems to mediate a harmful role being involved in motor neuron cell death, whereas TNFR1 signaling mediates neuroprotective effects, promoting the expression and secretion of trophic factors. This suggests that a better understanding of the cytokine impact on ALS progression may enable the development of effective therapies aimed at strengthening the protective roles of TNFα and at suppressing the detrimental ones.

A TNFR2-hnRNPK Axis Promotes Primary Liver Cancer Development via Activation of YAP Signaling in Hepatic Progenitor Cells.

Most primary liver cancer (PLC) cases progress mainly due to underlying chronic liver inflammation, yet the underlying mechanisms of inflammation-mediated PLC remain unclear. Here we uncover a TNF receptor II (TNFR2)-hnRNPK-YAP signaling axis in hepatic progenitor cells (HPC) essential for PLC development. TNFR2, but not TNF receptor I (TNFR1), was required for TNFα-induced activation of YAP during malignant transformation of HPCs and liver tumorigenesis. Mechanistically, heterogeneous nuclear ribonuclear protein K (hnRNPK) acted downstream of TNFα-TNFR2 signaling to directly interact with and stabilize YAP on target gene promoters genome-wide, therefore coregulating the expression of YAP target genes. Single-cell RNA sequencing confirmed the association of TNFR2-hnRNPK with YAP expression and the pathologic importance of HPC. Accordingly, expressions of TNFR2, hnRNPK, and YAP were all upregulated in PLC tissues and were strongly associated with poor prognosis of PLC including patient survival. Collectively, this study clarifies the differential roles of TNFRs in HPC-mediated tumorigenesis, uncovering a TNFR2-hnRNPK-centered mechanistic link between the TNFα-mediated inflammatory milieu and YAP activation in HPCs during PLC development. SIGNIFICANCE: This work defines how hnRNPK links TNFα signaling and Hippo pathway transcription coactivator YAP in hepatic progenitor cells during primary liver tumorigenesis.

TNFR1-d2 carrying the p.(Thr79Met) pathogenic variant is a potential novel actor of TNF\u03b1/TNFR1 signalling regulation in the pathophysiology of TRAPS

Binding of tumour necrosis factor α (TNFα) to its receptor (TNFR1) is critical for both survival and death cellular pathways. TNFα/TNFR1 signalling is complex and tightly regulated at different levels to control cell fate decisions. Previously, we identified TNFR1-d2, an exon 2-spliced transcript of TNFRSF1A gene encoding TNFR1, whose splicing may be modulated by polymorphisms associated with inflammatory disorders. Here, we investigated the impact of TNFRSF1A variants involved in TNFR-associated periodic syndrome (TRAPS) on TNFR1-d2 protein expression and activity. We found that TNFR1-d2 could be translated by using an internal translation initiation codon and a de novo internal ribosome entry site (IRES), which resulted in a putative TNFR1 isoform lacking its N-terminal region. The kinetic of assembly of TNFR1-d2 clusters at the cell surface was reduced as compared with full-length TNFR1. Although co-localized with the full-length TNFR1, TNFR1-d2 neither activated nuclear factor (NF)-κB signalling, nor interfered with TNFR1-induced NF-κB activation. Translation of TNFR1-d2 carrying the severe p.(Thr79Met) pathogenic variant (also known as T50M) was initiated at the mutated codon, resulting in an elongated extracellular domain, increased speed to form preassembled clusters in absence of TNFα, and constitutive NF-κB activation. Overall, TNFR1-d2 might reflect the complexity of the TNFR1 signalling pathways and could be involved in TRAPS pathophysiology of patients carrying the p.(Thr79Met) disease-causing variant.

Scan and Unlock: A Programmable DNA Molecular Automaton for Cell-Selective Activation of Ligand-Based Signaling.

Selective modulation of ligand-receptor interaction is essential in targeted therapy. In this study, we design an intelligent "scan and unlock" DNA automaton (SUDA) system to equip a native protein-ligand with cell-identity recognition and receptor-mediated signaling in a cell-type-specific manner. Using embedded DNA-based chemical reaction networks (CRNs) on the cell surface, SUDA scans and evaluates molecular profiles of cell-surface proteins via Boolean logic circuits. Therefore, it achieves cell-specific signal modulation by quickly unlocking the protein-ligand in proximity to the target cell-surface to activate its cognate receptor. As a proof of concept, we non-genetically engineered hepatic growth factor (HGF) with distinct logic SUDAs to elicit target cell-specific HGF signaling and wound healing behaviors in multiple heterogeneous cell types. Furthermore, the versatility of the SUDA strategy was shown by engineering tumor necrotic factor-α (TNFα) to induce programmed cell death of target cell subpopulations through cell-specific modulation of TNFR1 signaling.

Scan and Unlock: A Programmable DNA Molecular Automaton for Cell‐Selective Activation of Ligand‐Based Signaling

AbstractSelective modulation of ligand–receptor interaction is essential in targeted therapy. In this study, we design an intelligent “scan and unlock” DNA automaton (SUDA) system to equip a native protein‐ligand with cell‐identity recognition and receptor‐mediated signaling in a cell‐type‐specific manner. Using embedded DNA‐based chemical reaction networks (CRNs) on the cell surface, SUDA scans and evaluates molecular profiles of cell‐surface proteins via Boolean logic circuits. Therefore, it achieves cell‐specific signal modulation by quickly unlocking the protein‐ligand in proximity to the target cell‐surface to activate its cognate receptor. As a proof of concept, we non‐genetically engineered hepatic growth factor (HGF) with distinct logic SUDAs to elicit target cell‐specific HGF signaling and wound healing behaviors in multiple heterogeneous cell types. Furthermore, the versatility of the SUDA strategy was shown by engineering tumor necrotic factor‐α (TNFα) to induce programmed cell death of target cell subpopulations through cell‐specific modulation of TNFR1 signaling.

ABIN-1 is a key regulator in RIPK1-dependent apoptosis (RDA) and necroptosis, and ABIN-1 deficiency potentiates necroptosis-based cancer therapy in colorectal cancer

ABIN-1, also called TNIP1, is an ubiquitin-binding protein that serves an important role in suppressing RIPK1-independent apoptosis, necroptosis, and NF-κB activation. However, the involvement of ABIN-1 in the regulation of RIPK1-dependent apoptosis (RDA) is unknown. In this study, we found that poly(I:C) + TAK1 inhibitor 5Z-7-oxozeaenol (P5) concurrently induces RDA and necroptosis in Abin-1−/−, but not in Abin-1+/+ mouse embryonic fibroblasts (MEFs). Upon P5 stimulation, cells initially die by necroptosis and subsequently by RDA. Furthermore, we explored the therapeutic effect of ABIN-1 deficiency in necroptosis-based cancer therapy in colorectal cancer (CRC). We found that poly(I:C) + 5Z-7-oxozeaenol + IDN-6556 (P5I) yields a robust pro-necroptosis response, and ABIN-1 deficiency additionally enhances this P5I-induced necroptosis. Moreover, phase I/II cIAP inhibitor birinapant with clinical caspase inhibitor IDN-6556 (BI) alone and 5-fluorouracil with IDN-6556 (FI) alone are sufficient to induce necroptotic cell death in CRC cells by promoting auto-secretion of tumor necrosis factor (TNF); ABIN-1 deficiency amplifies the BI- or FI-induced necroptosis. Two independent xenograft experiments using HT-29 or COLO205 cells show that both BI and P5I remarkably inhibit tumor growth via necroptosis activation. For poly(I:C)-induced cell death, the sensitizing effect of ABIN-1 deficiency on cell death may be attributed to increased expression of TLR3. In TNF-induced necroptosis, ABIN-1 deficiency increases TNF-induced RIPK1 polyubiquitination by reducing the recruitment of ubiquitin-editing enzyme A20 to the TNFR1 signaling complex and induces more TNF secretion in CRC cells upon pro-necroptosis stimulation. With this combined data, ABIN-1 deficiency promotes greater sensitization of CRC cells to necroptosis.

Tumor necrosis factor receptor signaling modulates carcinogenesis in a mouse model of breast cancer

Pro-inflammatory conditions have long been associated with mammary carcinogenesis and breast cancer progression. The underlying mechanisms are incompletely understood but signaling of pro-inflammatory cytokine TNFα through its receptors TNFR1 and TNFR2 is a major mediator of inflammation in both obesity and in the response of tissues to radiation, 2 known risk factors for the development of breast cancer. Here, we demonstrated the loss of one TNFR2 allele led to ductal hyperplasia in the mammary gland with increased numbers of mammary epithelial stem cell and terminal end buds. Furthermore, loss of one TNFR2 allele increased the incidence of breast cancer in MMTV-Wnt1 mice and resulted in tumors with a more aggressive phenotype and metastatic potential. The underlying mechanisms include a preferential activation of canonical NF-κB signaling pathway and autocrine production of TNFα. Analysis of the TCGA dataset indicated inferior overall survival for patients with down-regulated TNFR2 expression. These findings unravel the imbalances in TNFR signaling promote the development and progression of breast cancer, indicating that selective agonists of TNFR2 could potentially modulate the risk for breast cancer in high-risk populations.

Single Cell Transcriptomics Implicate Novel Monocyte and T Cell Immune Dysregulation in Sarcoidosis.

Sarcoidosis is a systemic inflammatory disease characterized by infiltration of immune cells into granulomas. Previous gene expression studies using heterogeneous cell mixtures lack insight into cell-type-specific immune dysregulation. We performed the first single-cell RNA-sequencing study of sarcoidosis in peripheral immune cells in 48 patients and controls. Following unbiased clustering, differentially expressed genes were identified for 18 cell types and bioinformatically assessed for function and pathway enrichment. Our results reveal persistent activation of circulating classical monocytes with subsequent upregulation of trafficking molecules. Specifically, classical monocytes upregulated distinct markers of activation including adhesion molecules, pattern recognition receptors, and chemokine receptors, as well as enrichment of immunoregulatory pathways HMGB1, mTOR, and ephrin receptor signaling. Predictive modeling implicated TGFβ and mTOR signaling as drivers of persistent monocyte activation. Additionally, sarcoidosis T cell subsets displayed patterns of dysregulation. CD4 naïve T cells were enriched for markers of apoptosis and Th17/Treg differentiation, while effector T cells showed enrichment of anergy-related pathways. Differentially expressed genes in regulatory T cells suggested dysfunctional p53, cell death, and TNFR2 signaling. Using more sensitive technology and more precise units of measure, we identify cell-type specific, novel inflammatory and regulatory pathways. Based on our findings, we suggest a novel model involving four convergent arms of dysregulation: persistent hyperactivation of innate and adaptive immunity via classical monocytes and CD4 naïve T cells, regulatory T cell dysfunction, and effector T cell anergy. We further our understanding of the immunopathology of sarcoidosis and point to novel therapeutic targets.

TNFR2 Is a Crucial Hub Controlling Mesenchymal Stem Cell Biological and Functional Properties.

Mesenchymal stem cells (MSCs) have drawn lots of attention as gold standard stem cells in fundamental and clinical researches during the last 20 years. Due to their tissue and vascular repair capacities, MSCs have been used to treat a variety of degenerative disorders. Moreover, MSCs are able to modulate immune cells’ functions, particularly T cells while inducing regulatory T cells (iTregs). MSCs are very sensitive to inflammatory signals. Their biological functions could remarkably vary after exposure to different pro-inflammatory cytokines, notably TNFα. In this article, we have explored the importance of TNFR2 expression in a series of MSCs’ biological and functional properties. Thus, MSCs from wild-type (WT) and TNFR2 knockout (TNFR2 KO) mice were isolated and underwent several ex vivo experiments to investigate the biological significance of TNFR2 molecule in MSC main functions. Hampering in TNFR2 signaling resulted in reduced MSC colony-forming units and proliferation rate and diminished the expression of all MSC characteristic markers such as stem cell antigen-1 (Sca1), CD90, CD105, CD44, and CD73. TNFR2 KO-MSCs produced more pro-inflammatory cytokines like TNFα, IFNγ, and IL-6 and less anti-inflammatory mediators such as IL-10, TGFβ, and NO and induced Tregs with less suppressive effect. Furthermore, the TNFR2 blockade remarkably decreased MSC regenerative functions such as wound healing, complex tube formation, and endothelial pro-angiogenic support. Therefore, our results reveal the TNFα–TNFR2 axis as a crucial regulator of MSC immunological and regenerative functions.

Ubiquitination of RIPK1 regulates its activation mediated by TNFR1 and TLRs signaling in distinct manners

RIPK1 is a death-domain (DD) containing kinase involved in regulating apoptosis, necroptosis and inflammation. RIPK1 activation is known to be regulated by its DD-mediated interaction and ubiquitination, though underlying mechanisms remain incompletely understood. Here we show that K627 in human RIPK1-DD and its equivalent K612 in murine RIPK1-DD is a key ubiquitination site that regulates the overall ubiquitination pattern of RIPK1 and its DD-mediated interactions with other DD-containing proteins. K627R/K612R mutation inhibits the activation of RIPK1 and blocks both apoptosis and necroptosis mediated by TNFR1 signaling. However, Ripk1K612R/K612R mutation sensitizes cells to necroptosis and caspase-1 activation in response to TLRs signaling. Ripk1K612R/K612R mice are viable, but develop age-dependent reduction of RIPK1 expression, spontaneous intestinal inflammation and splenomegaly, which can be rescued by antibiotic treatment and partially by Ripk3 deficiency. Furthermore, we show that the interaction of RIPK1 with FADD contributes to suppressing the activation of RIPK3 mediated by TLRs signaling. Our study demonstrates the distinct roles of K612 ubiquitination in mRIPK1/K627 ubiquitination in hRIPK1 in regulating its pro-death kinase activity in response to TNFα and pro-survival activity in response to TLRs signaling.

Novel natural plant protein and mimetic peptides rescues aberrant brain‐energy metabolism and Alzheimer’s disease pathology

AbstractBackgroundExtensive evidence has indicated that a high rate of cholesterol biogenesis and abnormal neuronal energy metabolism play key roles in Alzheimer’s disease (AD) pathogenesis. Here, for the first time, we used protein and peptide, a plant protein homolog of mammalian adiponectin, to determine its therapeutic efficacy in different AD models.MethodMice were grouped before treatment as follows: WT and Transgenic mice (APP/PS1 and Adipo‐/‐ mice) were administered via intraperitoneal injection with 3 types of solution (saline, osmotin and osmotin mimetic peptide). Mice were decapitated at the age of 5, 9, 12 or 16 months. Protein samples were analyzed by immunobloting as well as immunofluorescence. Brain sections were analyzed by immune histochemistry. LTP was measured by mEPSC.ResultOsmotin, natural plant protein, and its mimetic peptide treatment modulated adiponectin receptor 1 (AdipoR1), significantly induced AMPK/SIRT1 activation, and reduced SREBP2 expression in both in vivo and in vitro AD and Adiponectin deficient mice. Osmotin acts Via AdipoR1/AMPK/SIRT1/SREBP2 and TNFR1 signaling pathway, Osmotin and its mimetic peptide significantly diminished amyloidogenic Aβ production, abundance and aggregation, accompanied by improved pre‐ and post‐synaptic dysfunction, cognitive impairment, memory deficits. Most importantly, it reversed the suppression of long‐term potentiation (LTP) in AD mice. Interestingly, AdipoR1, AMPK, and SIRT1 silencing not only abolished Osmotin capability but also further enhanced AD pathology by increasing SREBP2, APP, and β‐secretase (BACE1) expression and the levels of toxic Aβ production. Likewise, mimetic peptide mechanistically instigates AdipoR1/AMPK signaling and consequently suppressed the hyperactivated TNF‐α/TNFR1 signaling in both in vivo and in vitro models of AD.ConclusionOsmotin and its mimetic peptide mitigate aberrant brain‐energy metabolism and AD pathology in in vivo and in vitro AD models via regulating AdipoR1/AMPK/SIRT1/SREBP2/TNFR1 signaling pathway. These results suggest that Osmotin and peptide‐based mimetics can be a potential candidate for AD treatment.

Tumor Necrosis Factor Receptors: Pleiotropic Signaling Complexes and Their Differential Effects.

Since its discovery in 1975, TNFα has been a subject of intense study as it plays significant roles in both immunity and cancer. Such attention is well deserved as TNFα is unique in its engagement of pleiotropic signaling via its two receptors: TNFR1 and TNFR2. Extensive research has yielded mechanistic insights into how a single cytokine can provoke a disparate range of cellular responses, from proliferation and survival to apoptosis and necrosis. Understanding the intracellular signaling pathways induced by this single cytokine via its two receptors is key to further revelation of its exact functions in the many disease states and immune responses in which it plays a role. In this review, we describe the signaling complexes formed by TNFR1 and TNFR2 that lead to each potential cellular response, namely, canonical and non-canonical NF-κB activation, apoptosis and necrosis. This is followed by a discussion of data from in vivo mouse and human studies to examine the differential impacts of TNFR1 versus TNFR2 signaling.

Transition from TNF-Induced Inflammation to Death Signaling.

Tumor necrosis factor (TNF) plays a key role in inflammatory responses and in various cellular events such as apoptosis and necroptosis. The interaction of TNF with its receptor, TNFR1, drives the initiation of complex molecular pathways leading to inflammation and cell death. RARγ is released from the nucleus to orchestrate the formation of the cytosolic death complexes, and it is cytosolic RARγ that plays a pivotal role in switching TNF-induced inflammatory responses to RIPK1-initiated cell death. Thus, RARγ provides a checkpoint for the transition from inflammatory signaling to death machinery of RIPK1-initiated cell death in response to TNF. Here, we use techniques to identify RARγ as a downstream mediator of TNFR1 signaling complex. We use confocal imaging to show the localization of RARγ upon activation of cell death. Immunoprecipitation of RARγ identified the interacting proteins.

Induction of Antigen-Independent Proliferation of Regulatory T-Cells by TNF Superfamily Ligands OX40L and GITRL.

TNF receptor superfamily comprises many T-cell costimulatory receptors, including TNFRSF1, TNFRSF2, TNFRSF4 (OX40), TNFRSF9 (4-1BB), TNFRSF18 (GITR), and TNFRSF7 (CD27). Signaling through these costimulatory stimulatory receptors can promote conventional T-cell (Tconv) proliferation, and effector functions in an antigen-dependent manner. Thus, agonistic antibodies and ligands for OX40, 4-1BB, GITR, and CD27 have been tested for inducing T-cell-mediated antitumor responses in several cancers. However, recently emerging reports show critical role for TNFR signaling in regulatory T-cell (Treg) differentiation and expansion, which might suppress effector T-cell proliferation and functions. Here, we show preferential over expression of TNFR2, OX40, 4-1BB, and GITR in Treg cells over Tconv cells, and the ability of OX40L and GITRL to induce selective proliferation of Treg cells, but not Tconv cells, in an antigen-independent manner. We describe the standard protocols used for Affymetrix gene expression profiling, T-cell isolation, and Cell Trace Violet-based cell proliferation assay.

A systems-biology model of the tumor necrosis factor (TNF) interactions with TNF receptor 1 and 2

Clustering enables TNF receptors to stimulate intracellular signaling. The differential soluble ligand-induced clustering behavior of TNF receptor 1 (TNFR1) and TNFR2 was modeled. A structured, rule-based model implemented ligand-independent pre-ligand binding assembly domain (PLAD)-mediated homotypic low affinity interactions of unliganded and liganded TNF receptors. Soluble TNF initiates TNFR1 signaling but not TNFR2 signaling despite receptor binding unless it is secondarily oligomerized. We consider high affinity binding of TNF to signaling-incompetent pre-assembled dimeric TNFR1 and TNFR2 molecules and secondary clustering of liganded dimers to signaling competent ligand-receptor clusters. Published receptor numbers, affinities and measured different activities of clustered receptors validated model simulations for a large range of receptor and ligand concentrations. Different PLAD-PLAD affinities and different activities of receptor clusters explain the observed differences in the TNF receptor stimulating activities of soluble TNF. All scripts and data are in manuscript and supplement at Bioinformatics online. Supplementary data are available at Bioinformatics online.

Abstract 936: Targeting TNFR2 for cancer immunotherapy: Ligand blocking depletors versus receptor agonists

Abstract The pleiotropic TNF-α:TNFR axis plays a central role in the immune system. While the cellular expression of TNFR1 is broad, TNFR2 expression is mainly restricted to immune cells and especially high on T regs. The therapeutic potential of targeting TNFR2 for cancer treatment has been previously indicated but the mechanism-of-action (MoA) of these reagents remains unclear, with conflicting data reported by different investigators. To gain further insight, we identified and characterized a wide panel of human and mouse TNFR2-specific antibodies, generated from the n-CoDeR F.I.R.S.T™ phage display platform. Based on their ability to block TNF-α:TNFR2 binding and to agonize or antagonize TNFR2 signaling, we identified parallel human and mouse TNFR2-specific antibodies with activities ranging from agonist to antagonist, and from complete ligand blocking to non-blocking. Two antibody variants with distinctly opposing in vitro activities (complete ligand-blocking antagonist versus non-blocking agonist), were expressed in various IgG formats preferentially engaging activating FcγR (mIgG2a), inhibitory FcγR (mIgG1), or no FcγR (N297A Fc-mutated) and screened for in vivo antitumor activity. Both anti-TNFR2 antibody clones displayed anti-tumor efficacy but showed strikingly different FcγR-dependence for optimal antitumor activity. Further characterization demonstrated potent anti-tumor efficacy across several syngeneic in vivo cancer models (CT26, MC38 and B16), both as single agents, and when combined with anti-PD-1. In vivo mode-of-action studies indicated different initial events are evoked by the two antibodies but that they ultimately converge to elicit a similar immune modulation within the tumor that is associated with anti-tumor efficacy. The antagonist antibody caused early intra-tumoral T reg depletion, while the agonist caused dramatic CD8+ T cell increases. Over time, both antibodies induce an increase in effector T cells at the tumor site, improved CD8/T reg ratios, and tumor regression. In addition, the two antibodies similarly modulated the tumor myeloid content. Based on careful MoA-characterization, two human lead candidate anti-TNFR2 antibodies are being developed for treatment of solid cancer; BI-1808, a ligand-blocking T reg depleting antibody and BI-1910, a TNFR2 agonist. Citation Format: Linda Mårtensson, Kirstie Cleary, Monika Semmrich, Mathilda Kovacek, Petra Holmkvist, Caroline Svensson, Mimoza Demiri, Therese Blidberg, Ulla-Carin Thornberg, Vincentiu Pitic, Osman Dadas, Sean H. Lim, Stephen A. Beers, Mark S. Cragg, Björn Frendéus, Ingrid Teige. Targeting TNFR2 for cancer immunotherapy: Ligand blocking depletors versus receptor agonists [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 936.

Aberrant TNF Signaling Links RIPK3-Dependent Cell Death and Loss of TLR5 with Intestinal Inflammation and Dysbiosis

Intestinal homeostasis depends on the symbiotic nature of host-microbiota interactions. Whereas elevated TNF and dysbiosis are known hallmarks of inflammatory bowel disease (IBD), the mechanistic link between TNF, its cognate receptors, and the microbiome remains only partially understood. Using XIAP-deficiency as a murine model for a mendelian form of IBD, we show that the host-encoded TNF response cooperated with environmental cues to induce dysbiosis. Specifically, aberrant TNF signaling resulted in Paneth cell dysfunction, deregulated inflammatory pathways, and dysbiosis, which was characterized by loss of beneficial commensals. Mucosal inflammation was dependent on the individual action of TNF receptor (TNFR)1 and TNFR2. Mechanistically, aberrant TNFR2 signaling individually targeted IRF8+ lamina-propria dendritic cells to undergo MLKL-independent but RIPK3-driven cell death, whereas aberrant TNFR1 signaling also compromised Paneth cell function. Genetic loss of either receptor was sufficient to restore Clostridia and prevent intestinal inflammation. Primary patient data support the murine genetic evidence that TNFR2 promotes IBD in human patients. Our data show that the impairment of Paneth cells together with the inflammatory demise of dendritic cells is central for driving IBD and dysbiosis.

Structural optimization of a TNFR1-selective antagonistic TNFα mutant to create new-modality TNF-regulating biologics

Excessive activation of the proinflammatory cytokine tumor necrosis factor-α (TNFα) is a major cause of autoimmune diseases, including rheumatoid arthritis. TNFα induces immune responses via TNF receptor 1 (TNFR1) and TNFR2. Signaling via TNFR1 induces proinflammatory responses, whereas TNFR2 signaling is suggested to suppress the pathophysiology of inflammatory diseases. Therefore, selective inhibition of TNFR1 signaling and preservation of TNFR2 signaling activities may be beneficial for managing autoimmune diseases. To this end, we developed a TNFR1-selective, antagonistic TNFα mutant (R1antTNF). Here, we developed an R1antTNF derivative, scR1antTNF-Fc, which represents a single-chain form of trimeric R1antTNF with a human IgG-Fc domain. scR1antTNF-Fc had properties similar to those of R1antTNF, including TNFR1-selective binding avidity, TNFR1 antagonistic activity, and thermal stability, and had a significantly extended plasma t1/2in vivo In a murine rheumatoid arthritis model, scR1antTNF-Fc and 40-kDa PEG-scR1antTNF (a previously reported PEGylated form) delayed the onset of collagen-induced arthritis, suppressed arthritis progression in mice, and required a reduced frequency of administration. Interestingly, with these biologic treatments, we observed an increased ratio of regulatory T cells to conventional T cells in lymph nodes compared with etanercept, a commonly used TNF inhibitor. Therefore, scR1antTNF-Fc and 40-kDa PEG-scR1antTNF indirectly induced immunosuppression. These results suggest that selective TNFR1 inhibition benefits the management of autoimmune diseases and that R1antTNF derivatives hold promise as new-modality TNF-regulating biologics.

Prolonged effect associated with inflammatory response observed after exposure to low dose of tritium β-rays

Background: The value of relative biological effectiveness of tritium increases at low dose domain, which results in the suspicion of weighting factor of 1 for tritium after low dose exposure. Thus, present study was carried out to analyze the differences in the cellular responses at early and late period between low dose of tritium β-rays and γ-rays radiation.Methods: MCF-10A cells were exposed to low dose of tritium β-rays or γ-rays, then cellular behaviors, such as DNA double strand breaks (DSBs), apoptosis, reactive oxygen species (ROS) level and inflammatory relevant gene expression were analyzed at early and late period post-irradiation.Results: At early period the elimination of DSB foci produced by HTO is longer than γ-rays. High ROS level and a continual change of cell cycle distribution are observed in HTO radiation group. Based on the results of RNA sequencing, Ingenuity Pathway Analysis (IPA) indicates TNFR1 signaling and production of nitric oxide and ROS are activated as an acute response at 24 h post radiation. Moreover, it also shows a disturbance in cholesterol biosynthesis. The results of 30 days point that there is a lasting active inflammatory response, accompanying with a persistent high expression of relevant cytokines, such as TNF and IL1R.Conclusion: Compared to an acute response induced by γ-rays, a persistent inflammatory response exists in HTO-irradiated cells when cultured for 30 days, which might be related to accumulation of tritium in the form of organically bound tritium (OBT) in cellular DNA or lipids.

VCAM1/VLA4 interaction mediates Ly6Clow monocyte recruitment to the brain in a TNFR signaling dependent manner during fungal infection

Abstract Monocytes exist in two major populations, termed Ly6Chi and Ly6Clow monocytes. Compared to Ly6Chi monocytes, less is known about Ly6Clow monocyte recruitment and mechanisms involved in the recruitment of this subset. Furthermore, the role of Ly6Clow monocytes during infections is largely unknown. Here, using intravital microscopy, we demonstrate that Ly6Clow monocytes are predominantly recruited to the brain vasculature following infection with Cryptococcus neoformans, a fungal pathogen causing meningoencephalitis. The recruitment depends primarily on the interaction of VCAM1 expressed on the brain endothelium with VLA4 expressed on Ly6Clow monocytes. Furthermore, TNFR signaling is essential for the recruitment through enhancing VLA4 expression on Ly6Clow monocytes. Interestingly, the recruited Ly6Clow monocytes internalized C. neoformans and carried the organism while crawling on and adhering to the luminal wall of brain vasculature and migrating to the brain parenchyma. Our study reveals a substantial recruitment of Ly6Clow monocytes to the brain and highlights important properties of this subset during infection.