GITRL impairs hepatocyte repopulation by liver progenitor cells to aggravate inflammation and fibrosis by GITR+CD8+ T lymphocytes in CDE Mice.

As an alternative pathway for liver regeneration, liver progenitor cells and their derived ductular reaction cells increase during the progression of many chronic liver diseases. However, the mechanism underlying their hepatocyte repopulation after liver injury remains unknown. Here, we conducted progenitor cell lineage tracing in mice and found that fewer than 2% of hepatocytes were derived from liver progenitor cells after 9 weeks of injury with a choline-deficient diet supplemented with ethionine (CDE), and this percentage increased approximately three-fold after 3 weeks of recovery. We also found that the proportion of liver progenitor cells double positive for the ligand of glucocorticoid-induced tumour necrosis factor receptor (GITRL, also called Tnfsf18) and SRY-related HMG box transcription 9 (Sox9) among nonparenchymal cells increased time-dependently upon CDE injury and reduced after recovery. When GITRL was conditionally knocked out from hepatic progenitor cells, its expression in nonparenchymal cells was downregulated by approximately fifty percent, and hepatocyte repopulation increased by approximately three folds. Simultaneously, conditional knockout of GITRL reduced the proportion of liver-infiltrating CD8+ T lymphocytes and glucocorticoid-induced tumour necrosis factor receptor (GITR)-positive CD8+ T lymphocytes. Mechanistically, GITRL stimulated cell proliferation but suppressed the differentiation of liver progenitor organoids into hepatocytes, and CD8+ T cells further reduced their hepatocyte differentiation by downregulating the Wnt/ß-catenin pathway. Therefore, GITRL expressed by liver progenitor cells impairs hepatocyte differentiation, thus hindering progenitor cell-mediated liver regeneration.

Transcription factor FoxO1 regulates myoepithelial cell diversity and growth.

Salivary gland myoepithelial cells regulate saliva secretion and have been implicated in the histological diversity of salivary gland tumors. However, detailed functional analysis of myoepithelial cells has not been determined owing to the few of the specific marker to isolate them. We isolated myoepithelial cells from the submandibular glands of adult mice using the epithelial marker EpCAM and the cell adhesion molecule CD49f as indicators and found predominant expression of the transcription factor FoxO1 in these cells. RNA-sequence analysis revealed that the expression of cell cycle regulators was negatively regulated in FoxO1-overexpressing cells. Chromatin immunoprecipitation analysis showed that FoxO1 bound to the p21/p27 promoter DNA, indicating that FoxO1 suppresses cell proliferation through these factors. In addition, FoxO1 induced the expression of ectodysplasin A (Eda) and its receptor Eda2r, which are known to be associated with X-linked hypohidrotic ectodermal dysplasia and are involved in salivary gland development in myoepithelial cells. FoxO1 inhibitors suppressed Eda/Eda2r expression and salivary gland development in primordial organ cultures after mesenchymal removal. Although mesenchymal cells are considered a source of Eda, myoepithelial cells might be one of the resources of Eda. These results suggest that FoxO1 regulates myoepithelial cell proliferation and Eda secretion during salivary gland development in myoepithelial cells.

[Mechanism of Shikonin on spinal cord injury in rats based on TNFR/RIPK1 pathway].

OBJECTIVE: To explore the effect of shikonin on the recovery of nerve function after acute spinal cord injury(SCI) in rats. METHODS: 96 male Sprague-Dawley(SD)rats were divided into 4 groups randomly:sham operation group (Group A), sham operation+shikonin group (Group B), SCI+ DMSO(Group C), SCI+shikonin group (Group D).The acute SCI model of rats was made by clamp method in groups C and D . After subdural catheterization, no drug was given in group A. rats in groups B and D were injected with 100 mg·kg-1 of shikonin through catheter 30 min after modeling, and rats in group C were given with the same amount of DMSO, once a day until the time point of collection tissue. Basso-Beattie-Bresnahan(BBB) scores were performed on 8 rats in each group at 6, 12, and 3 d after moneling, and oblique plate tests were performed on 1, 3, 7 and 14 d after modeling, and then spinal cord tissues were collected. Eight rats were intraperitoneally injected with propidine iodide(PI) 1 h before sacrificed to detection PI positive cells at 24 h in each group. Eight rats were sacrificed in each group at 24 h after modeling, the spinal cord injury was observed by HE staining.The Nissl staining was used to observe survivor number of nerve cells. Western-blot technique was used to detect the expression levels of Bcl-2 protein and apoptosis related protein RIPK1. RESULTS: After modeling, BBB scores were normal in group A and B, but in group C and D were significantly higher than those in group A and B. And the scores in group D were higher than those in group C in each time point (P<0.05). At 12 h after modeling, the PI red stained cells in group D were significantly reduced compared with that in group C, and the disintegration of neurons was alleviated(P<0.05). HE and Nissl staining showed nerve cells with normal morphology in group A and B at 24h after operation. The degree of SCI and the number of neuronal survival in group D were better than those in group C, the difference was statistically significant at 24h (P<0.05). The expression of Bcl-2 and RIPK1 proteins was very low in group A and B;The expression of RIPK1 was significantly increased in Group C and decreased in Group D, with a statistically significant difference (P<0.05);The expression of Bcl-2 protein in group D was significantly higher than that in group C (P<0.05). CONCLUSION: Shikonin can alleviate the pathological changes after acute SCI in rats, improve the behavioral score, and promote the recovery of spinal nerve function. The specific mechanism may be related to the inhibition of TNFR/RIPK1 signaling pathway mediated necrotic apoptosis.

TNFRSF19 promotes endoplasmic reticulum stress-induced paraptosis via the activation of the MAPK pathway in triple-negative breast cancer cells.

TNFRSF19 is a member of the tumor necrosis factor receptor superfamily, and its function exhibits variability among different types of cancers. The influence of TNFRSF19 on triple-negative breast cancer (TNBC) has yet to be definitively established. In this study, bioinformatics analyses revealed that lower TNFRSF19 was associated with the poorer prognosis, higher lymph node metastasis and lower immune infiltration. Subsequently, data obtained from the TCGA database and collection of tissue samples revealed that the mRNA and protein expression levels of TNFRSF19 were observed to be significantly reduced in TNBC tissue compared to normal tissue. Additionally, the results of in vitro experiments have demonstrated that TNFRSF19 possessed the ability to inhibit the proliferation, migration and invasive capabilities of TNBC cells. In vivo trials elucidated that TNFRSF19 could suppress tumor xenografts growth. Mechanistically, TNFRSF19 initiated caspase-independent cell death and induced paraptosis. Moreover, rescue assays demonstrated that TNFRSF19 induced-paraptosis was facilitated by MAPK pathway-mediated endoplasmic reticulum (ER) stress. In conclusion, our findings demonstrated that the upregulation of TNFRSF19 functioned as a tumor suppressor in TNBC by stimulating paraptosis through the activation of the MAPK pathway-mediated ER stress, highlighting its potential to be a new therapeutic target for TNBC.

Tumour necrosis factor-α induces C-C motif chemokine ligand 5 production in canine keratinocytes.

BACKGROUND: C-C motif chemokine ligand (CCL)5 induces skin inflammation in healthy dogs. In addition, CCL5 is overexpressed in the skin of experimental models of canine atopic dermatitis (cAD). Tumour necrosis factor (TNF)-α has been shown to be upregulated in cAD. However, it remains unclear whether TNF-α induces CCL5 production in canine keratinocytes. HYPOTHESIS/OBJECTIVES: To determine the effect of TNF-α on CCL5 production in canine keratinocyte culture and investigate possible synergy with interferon (IFN)-γ and interleukin (IL)-4. MATERIALS AND METHODS: CCL5 protein concentrations were measured by enzyme-linked immunosorbent assay (ELISA) in the culture supernatant of a cell line of canine progenitor epidermal keratinocyte (CPEK) cells stimulated with TNF-α with or without inhibitors of the TNF receptor signalling pathway. CCL5 protein concentrations also were measured in CPEK cells stimulated with TNF-α in the absence or presence of IFN-γ, a T-helper (Th)1-type cytokine, and/or IL-4, a Th2-type cytokine. RESULTS: TNF-α increased CCL5 production in CPEK cells in time- and dose-dependent manners. Inhibitors of the TNF receptor signalling pathway diminished CCL5 production. Although neither IFN-γ nor IL-4 alone induced CCL5 production in CPEK cells, the combination of TNF-α and IFN-γ, and not IL-4, synergistically enhanced CCL5 production in these cells. CONCLUSIONS AND CLINICAL RELEVANCE: TNF-α may be involved in skin inflammation in dogs by promoting CCL5 production in keratinocytes. Furthermore, the synergistic effect of TNF-α and IFN-γ suggests that the local Th1-type milieu may aggravate skin inflammation. Further studies are required to elucidate the role of TNF-α-induced CCL5 production of keratinocytes in the pathogenesis of cAD.

Impact of Targeting Moiety Type and Protein Corona Formation on the Uptake of Fn14-Targeted Nanoparticles by Cancer Cells.

The TWEAK receptor, Fn14, is a promising candidate for active targeting of cancer nanotherapeutics to many solid tumor types, including metastatic breast and primary brain cancers. Targeting of therapeutic nanoparticles (NPs) has been accomplished using a range of targeting moieties including monoclonal antibodies and related fragments, peptides, and small molecules. Here, we investigated a full-length Fn14-specific monoclonal antibody, ITEM4, or an ITEM4-Fab fragment as a targeting moiety to guide the development of a clinical formulation. We formulated NPs with varying densities of the targeting moieties while maintaining the decreased nonspecific adhesivity with receptor targeting (DART) characteristics. To model the conditions that NPs experience following intravenous infusion, we investigated the impact of serum exposure in relation to the targeting moiety type and surface density. To further evaluate performance at the cancer cell level, we performed experiments to assess differences in cellular uptake and trafficking in several cancer cell lines using confocal microscopy, imaging flow cytometry, and total internal reflection fluorescence microscopy. We observed that Fn14-targeted NPs exhibit enhanced cellular uptake in Fn14-high compared to Fn14-low cancer cells and that in both cell lines uptake levels were greater than observed with control, nontargeted NPs. We found that serum exposure increased Fn14-targeted NP specificity while simultaneously reducing the total NP uptake. Importantly, serum exposure caused a larger reduction in cancer cell uptake over time when the targeting moiety was an antibody fragment (Fab region of the monoclonal antibody) compared with the full-length monoclonal antibody targeting moiety. Lastly, we uncovered that full monoclonal antibody-targeted NPs enter cancer cells via clathrin-mediated endocytosis and traffic through the endolysosomal pathway. Taken together, these results support a pathway for developing a clinical formulation using a full-length Fn14 monoclonal antibody as the targeting moiety for a DART cancer nanotherapeutic agent.

Reconciling intrinsic properties of activating TNF receptors by native ligands versus synthetic agonists.

The extracellular domain of tumor necrosis factor receptors (TNFR) generally require assembly into a homotrimeric quaternary structure as a prerequisite for initiation of signaling via the cytoplasmic domains. TNF receptor homotrimers are natively activated by similarly homo-trimerized TNF ligands, but can also be activated by synthetic agonists including engineered antibodies and Fc-ligand fusion proteins. A large body of literature from pre-clinical models supports the hypothesis that synthetic agonists targeting a diverse range of TNF receptors (including 4-1BB, CD40, OX40, GITR, DR5, TNFRSF25, HVEM, LTßR, CD27, and CD30) could amplify immune responses to provide clinical benefit in patients with infectious diseases or cancer. Unfortunately, however, the pre-clinical attributes of synthetic TNF receptor agonists have not translated well in human clinical studies, and have instead raised fundamental questions regarding the intrinsic biology of TNF receptors. Clinical observations of bell-shaped dose response curves have led some to hypothesize that TNF receptor overstimulation is possible and can lead to anergy and/or activation induced cell death of target cells. Safety issues including liver toxicity and cytokine release syndrome have also been observed in humans, raising questions as to whether those toxicities are driven by overstimulation of the targeted TNF receptor, a non-TNF receptor related attribute of the synthetic agonist, or both. Together, these clinical findings have limited the development of many TNF receptor agonists, and may have prevented generation of clinical data which reflects the full potential of TNF receptor agonism. A number of recent studies have provided structural insights into how different TNF receptor agonists bind and cluster TNF receptors, and these insights aid in deconvoluting the intrinsic biology of TNF receptors with the mechanistic underpinnings of synthetic TNF receptor agonist therapeutics.

Ginkgolide A downregulates transient receptor potential (melastatin) 2 to protect cisplatin-induced acute kidney injury in rats through the TWEAK/Fn14 pathway: Ginkgolide A improve acute renal injury.

PURPOSE: In order to seek effective drugs for treating cisplatin-induced acute renal injury and explore the corresponding potential mechanism. METHODS: Mouse kidney injury model was established by intraperitoneal injection of 20 mg/kg cisplatin. The temporal expression of TRPM2 and the regulation of Ginkgolide A on its expression were analyzed by western blot. In order to perform the mechanical analysis, we used TRPM2-KO knockout mice. In this study, we evaluated the repair effect of GA on acute kidney injury through renal function factors, inflammatory factors and calcium and potassium content. Pathological injury and cell apoptosis were detected by H&E and TUNEL, respectively. RESULT: Ginkgolide A inhibited inflammatory reaction and excessive oxidative stress, reduced renal function parameters, and improved pathological injury. Meanwhile, we also found that the repair effect of Ginkgolide A on renal injury is related to TRPM2, and Ginkgolide A downregulated TRPM2 expression and inactivated TWEAK/Fn14 pathway in cisplatin-induced renal injury model. We also found that inhibition of TWEAK/Fn14 pathway was more effective in TRPM2-KO mice than TRPM2-WT mice. CONCLUSION: Ginkgolide A was the effective therapeutic drug for cisplatin-induced renal injury through acting on TRPM2, and TWEAK/Fn14 pathway was the downstream pathway of Ginkgolide A in acute renal injury, and Ginkgolide A inhibited TWEAK/Fn14 pathway in cisplatin-induced renal injury model.

Inducible nitric oxide synthase activity mediates TNF-α-induced endothelial cell dysfunction.

Inducible nitric oxide synthase (iNOS) and vascular endothelial dysfunction have been implicated in the development and progression of atherosclerosis. This study aimed to elucidate the role of iNOS in vascular endothelial dysfunction. Ultrahigh performance liquid chromatography-quadrupole time-of-flight mass spectrometry combined with multivariate data analysis was used to characterize the metabolic changes in human umbilical vein endothelial cells (HUVECs) in response to different treatment conditions. In addition, molecular biology techniques were employed to explain the molecular mechanisms underlying the role of iNOS in vascular endothelial dysfunction. Tumor necrosis factor-α (TNF-α) enhances the expression of iNOS, TXNIP, and the level of reactive oxygen species (ROS) facilitates the entry of nuclear factor-κB (NF-κB) into the nucleus and promotes injury in HUVECs. iNOS deficiency reversed the TNF-α-mediated pathological changes in HUVECs. Moreover, TNF-α increased the expression of tumor necrosis factor receptor-2 (TNFR-2) and the levels of p-IκBα and IL-6 proteins and CD31, ICAM-1, and VCAM-1 protein expression, which was significantly reduced in HUVECs with iNOS deficiency. In addition, treating HUVECs in the absence or presence of TNF-α or iNOS, respectively, enabled the identification of putative endogenous biomarkers associated with endothelial dysfunction. These biomarkers were involved in critical metabolic pathways, including glycosylphosphatidylinositol-anchor biosynthesis, amino acid metabolism, sphingolipid metabolism, and fatty acid metabolism. iNOS deficiency during vascular endothelial dysfunction may affect the expression of TNFR-2, vascular adhesion factors, and the level of ROS via cellular metabolic changes, thereby attenuating vascular endothelial dysfunction.NEW & NOTEWORTHY Inducible nitric oxide synthase (iNOS) deficiency during vascular endothelial dysfunction may affect the expression of tumor necrosis factor receptor-2 and vascular adhesion factors via cellular metabolic changes, thereby attenuating vascular endothelial dysfunction.

Antibody-based soluble and membrane-bound TWEAK mimicking agonists with FcγR-independent activity.

Fibroblast growth factor (FGF)-inducible 14 (Fn14) activates the classical and alternative NFκB (nuclear factor 'kappa-light-chain-enhancer' of activated B-cells) signaling pathway but also enhances tumor necrosis factor (TNF)-induced cell death. Fn14 expression is upregulated in non-hematopoietic cells during tissue injury and is also often highly expressed in solid cancers. In view of the latter, there were and are considerable preclinical efforts to target Fn14 for tumor therapy, either by exploiting Fn14 as a target for antibodies with cytotoxic activity (e.g. antibody-dependent cellular cytotoxicity (ADCC)-inducing IgG variants, antibody drug conjugates) or by blocking antibodies with the aim to interfere with protumoral Fn14 activities. Noteworthy, there are yet no attempts to target Fn14 with agonistic Fc effector function silenced antibodies to unleash the proinflammatory and cell death-enhancing activities of this receptor for tumor therapy. This is certainly not at least due to the fact that anti-Fn14 antibodies only act as effective agonists when they are presented bound to Fcγ receptors (FcγR). Thus, there are so far no antibodies that robustly and selectively engage Fn14 signaling without triggering unwanted FcγR-mediated activities. In this study, we investigated a panel of variants of the anti-Fn14 antibody 18D1 of different valencies and domain architectures with respect to their inherent FcγR-independent ability to trigger Fn14-associated signaling pathways. In contrast to conventional 18D1, the majority of 18D1 antibody variants with four or more Fn14 binding sites displayed a strong ability to trigger the alternative NFκB pathway and to enhance TNF-induced cell death and therefore resemble in their activity soluble (TNF)-like weak inducer of apoptosis (TWEAK), one form of the natural occurring ligand of Fn14. Noteworthy, activation of the classical NFκB pathway, which naturally is predominately triggered by membrane-bound TWEAK but not soluble TWEAK, was preferentially observed with a subset of constructs containing Fn14 binding sites at opposing sites of the IgG scaffold, e.g. IgG1-scFv fusion proteins. A superior ability of IgG1-scFv fusion proteins to trigger classical NFκB signaling was also observed with the anti-Fn14 antibody PDL192 suggesting that we identified generic structures for Fn14 antibody variants mimicking soluble and membrane-bound TWEAK.

Head or tail? A molecular dynamics approach to the complex structure of TNF-associated factor TRAF2.

Tumor necrosis factor receptor-associated factor proteins (TRAFs) are trimeric proteins that play a fundamental role in signaling, acting as intermediaries between the tumor necrosis factor (TNF) receptors and the proteins that transmit the downstream signal. The monomeric subunits of all the TRAF family members share a common tridimensional structure: a C-terminal globular domain and a long coiled-coil tail characterizing the N-terminal section. In this study, the dependence of the TRAF2 dynamics on the length of its tail was analyzed in silico. In particular, we used the available crystallographic structure of a C-terminal fragment of TRAF2 (168 out of 501 a.a.), TRAF2-C, and that of a longer construct, addressed as TRAF2-plus, that we have re-constructed using the AlphaFold2 code. The results indicate that the longer N-terminal tail of TRAF2-plus has a strong influence on the dynamics of the globular regions in the protein C-terminal head. In fact, the quaternary interactions among the TRAF2-C subunits change asymmetrically in time, while the movements of TRAF2-plus monomers are rather limited and more ordered than those of the shorter construct. Such findings shed a new light on the dynamics of TRAF subunits and on the protein mechanism in vivo, since TRAF monomer-trimer equilibrium is crucial for several reasons (receptor recognition, membrane binding, hetero-oligomerization).

Fundamental Characterization of Antibody Fusion-Single-Chain TNF Recombinant Proteins Directed against Costimulatory TNF Receptors Expressed by T-Lymphocytes.

The costimulatory signal regulated by the members of the tumor necrosis factor receptor (TNFR) superfamily expressed by T cells plays essential roles for T cell responses and has emerged as a promising target for cancer immunotherapy. However, it is unclear how the difference in TNFR costimulation contributes to T cell responses. In this study, to clarify the functional significance of four different TNFRs, OX40, 4-1BB, CD27 and GITR, we prepared corresponding single-chain TNF ligand proteins (scTNFLs) connected to IgG Fc domain with beneficial characteristics, i.e., Fc-scOX40L, Fc-sc4-1BBL, Fc-scCD27L (CD70) and Fc-scGITRL. Without intentional cross-linking, these soluble Fc-scTNFL proteins bound to corresponding TNFRs induced NF-kB signaling and promoted proliferative and cytokine responses in CD4+ and CD8+ T cells with different dose-dependencies in vitro. Mice injected with one of the Fc-scTNFL proteins displayed significantly augmented delayed-type hypersensitivity responses, showing in vivo activity. The results demonstrate that each individual Fc-scTNFL protein provides a critical costimulatory signal and exhibits quantitatively distinct activity toward T cells. Our findings provide important insights into the TNFR costimulation that would be valuable for investigators conducting basic research in cancer immunology and also have implications for T cell-mediated immune regulation by designer TNFL proteins.

The Drosophila tumor necrosis factor receptor, Wengen, couples energy expenditure with gut immunity.

It is well established that tumor necrosis factor (TNF) plays an instrumental role in orchestrating the metabolic disorders associated with late stages of cancers. However, it is not clear whether TNF/TNF receptor (TNFR) signaling controls energy homeostasis in healthy individuals. Here, we show that the highly conserved Drosophila TNFR, Wengen (Wgn), is required in the enterocytes (ECs) of the adult gut to restrict lipid catabolism, suppress immune activity, and maintain tissue homeostasis. Wgn limits autophagy-dependent lipolysis by restricting cytoplasmic levels of the TNFR effector, TNFR-associated factor 3 (dTRAF3), while it suppresses immune processes through inhibition of the dTAK1/TAK1-Relish/NF-κB pathway in a dTRAF2-dependent manner. Knocking down dTRAF3 or overexpressing dTRAF2 is sufficient to suppress infection-induced lipid depletion and immune activation, respectively, showing that Wgn/TNFR functions as an intersection between metabolism and immunity allowing pathogen-induced metabolic reprogramming to fuel the energetically costly task of combatting an infection.

LC3-independent autophagy is vital to prevent TNF cytotoxicity.

The (macro)autophagy field is facing a paradigm shift after the recent discovery that cytosolic cargoes can still be selectively targeted to phagophores (the precursors to autophagosomes) even in the absence of LC3 or other Atg8-protein family members. Several in vitro studies have indeed reported on the existence of an unconventional selective autophagic pathway that involves the in-situ formation of an autophagosome around the cargo through the direct selective autophagy receptor-mediated recruitment of RB1CC1/FIP200, thereby bypassing the requirement of LC3. In an article recently published in Science, we demonstrate the physiological importance of this unconventional autophagic pathway in the context of TNF (tumor necrosis factor) signaling. We show that it promotes the degradation of the cytotoxic TNFRSF1A/TNFR1 (TNF receptor superfamily member 1A) complex II that assembles upon TNF sensing and thereby protects mice from TNFRSF1A-driven embryonic lethality and skin inflammation.Abbreviations: ATG: autophagy related; CASP: caspase; FIR: RB1CC1/FIP200-interacting region; LIR: LC3-interacting region; M1: linear; PAS: phagophore assembly site; PtdIns3K: phosphatidylinositol 3-kinase; TNF: tumor necrosis factor; TNFRSF1A: TNF receptor superfamily member 1A.

Noninvasive Imaging OX40+ Activated T Cells Provides Early Warning of Rheumatoid Arthritis.

PURPOSE: The goal of this study was to develop an imaging probe-IRDye-680RD-OX40 mAb-that can be used for noninvasive imaging and optical imaging of rheumatoid arthritis (RA). OX40/OX40 ligand (OX40L) interactions have been shown to exert potent costimulatory effects on T cell activation. Detectable change in T cell activation profiles was observed in early RA. METHODS: OX40 expression pattern was analyzed by flow cytometry. N-hydroxysuccinimide (NHS) esters are used to label proteins selectively on free amino groups of OX40 monoclonal antibody (mAb). Characterization of IRDye-680RD-OX40 mAb was measured and a fluorescence spectrum gathered. Cell binding assay was also performed between activated and naïve murine T cells. Longitudinal near-infrared fluorescence (NIRF) imaging of the probe was performed on day 8, day 9, day 10, and day 11 of adjuvant-induced arthritis (AIA) mouse model. Paw thickness and body weight were compared between the OX40 mAb and IgG injection groups. RESULTS: NIRF imaging with IRDye-680RD-OX40 mAb revealed strong OX40-positive responses with high specificity. Flow analysis showed that OX40 was specifically expressed on the surface of T cells in RP and spleen of AIA model. The AIA group was significantly differentiated from the control group at all time points with imaging monitoring. The region of interest (ROI) was in line with ex vivo imaging and biodistribution study. This study highlights the potential utility of the OX40 NIRF imaging as a new strategy for RA prediction and T cell monitoring. CONCLUSION: The results provide evidence that IRDye-680RD-OX40 mAb detects organized T cells activation in early RA. The optical probe was capable of detection of RA pathogenesis. It identified transcriptional responses to RA that mediate its immune functions. Thus, it may be an ideal probe for RA imaging.

Basic characterization of antibodies targeting receptors of the tumor necrosis factor receptor superfamily.

Many new immunotherapeutic approaches aim on the stimulatory targeting of receptors of the tumor necrosis factor (TNF) receptor superfamily (TNFRSF) using antibodies with intrinsic or conditional agonism. There is an initial need to characterize corresponding TNFRSF receptor (TNFR)-targeting antibodies with respect to affinity, ligand binding, receptor activation and the epitope recognized. Here, we report a collection of simple and matched protocols enabling the detailed investigation of these aspects by help of Gaussia princeps luciferase (GpL) fusion proteins and analysis of interleukin-8 (IL8) production as an easily measurable readout of TNFR activation. In a first step, the antibodies and antibody variants of interest are transiently expressed in human embryonal kidney 293 cells, either in non-modified form or as fusion proteins with GpL as a reporter domain. The supernatants containing the antibody-GpL fusion proteins can then be used without further purification in cell-free and/or cellular binding studies to determine affinity. Similarly, binding studies with mutated TNFR variants enable the characterization of the antibody binding site within the TNFR ectodomain. Furthermore, in cellular binding studies with GpL fusion proteins of soluble TNFL molecules, the ability of the non-modified antibody variants to interfere with TNFL-TNFR interaction can be analyzed. Last but not least, we describe a protocol to determine the intrinsic and the Fc gamma receptor (FcγR)-dependent agonism of anti-TNFR antibodies which exploits i) the capability of TNFRs to trigger IL8 production in tumor cell lines lacking expression of FcγRs and ii) vector- and FcγR-transfected cells, which produce no or only very low amounts of human IL8. The presented protocols only require standard molecular biological equipment, eukaryotic cell culture and plate readers for the quantification of luminescent and colorimetric signals.

Ensemble-based molecular docking and spectrofluorometric analysis of interaction between cytotoxin and tumor necrosis factor receptor 1.

Cytotoxin (CTX) is a three-finger toxin presents predominantly in cobra venom. The functional site of the toxin is located at its three hydrophobic loop tips. Its actual mechanism of cytotoxicity remains inconclusive as few conflicting hypotheses have been proposed in addition to direct cytolytic effects. The present work investigated the interaction between CTX and death receptor families via ensemble-based molecular docking and fluorescence titration analysis. Multiple sequence alignments of different CTX isoforms obtained a conserved CTX sequence. The three-dimensional structure of the conserved CTX was later determined using homology modelling, and its quality was validated. Ensemble-based molecular docking of CTX was performed with different death receptors, such as Fas-ligand and tumor necrosis factor receptor families. Our results showed that tumor necrosis factor receptor 1 (TNFR1) was the best receptor interacting with CTX attributed to the interaction of all three functional loops and evinced with low HADDOCK, Z-score and RMSD value. The interaction between CTX and TNFR1 was also supported by a concentration-dependent reduction of fluorescence intensity with increasing binding affinity. The possible intermolecular interactions between CTX and TNFR1 were Van der Waals forces and hydrogen bonding. Our findings suggest a possibility that CTX triggers apoptosis cell death through non-covalent interactions with TNFR1.Communicated by Ramaswamy H. Sarma.

Computational analyses of the interactome between TNF and TNFR superfamilies.

Proteins in the tumor necrosis factor (TNF) superfamily (TNFSF) regulate diverse cellular processes by interacting with their receptors in the TNF receptor (TNFR) superfamily (TNFRSF). Ligands and receptors in these two superfamilies form a complicated network of interactions, in which the same ligand can bind to different receptors and the same receptor can be shared by different ligands. In order to study these interactions on a systematic level, a TNFSF-TNFRSF interactome was constructed in this study by searching the database which consists of both experimentally measured and computationally predicted protein-protein interactions (PPIs). The interactome contains a total number of 194 interactions between 18 TNFSF ligands and 29 TNFRSF receptors in human. We modeled the structure for each ligand-receptor interaction in the network. Their binding affinities were further computationally estimated based on modeled structures. Our computational outputs, which are all publicly accessible, serve as a valuable addition to the currently limited experimental resources to study TNF-mediated cell signaling.

Quantitative systems pharmacology model of GITR-mediated T cell dynamics in tumor microenvironment.

T cell interaction in the tumor microenvironment is a key component of immuno-oncology therapy. Glucocorticoid-induced tumor necrosis factor receptor (TNFR)-related protein (GITR) is expressed on immune cells including regulatory T cells (Tregs) and effector T cells (Teffs). Preclinical data suggest that agonism of GITR in combination with Fc-γ receptor-mediated depletion of Tregs results in increased intratumoral Teff:Treg ratio and tumor shrinkage. A novel quantitative systems pharmacology (QSP) model was developed for the murine anti-GITR agonist antibody, DTA-1.mIgG2a, to describe the kinetics of intratumoral Tregs and Teffs in Colon26 and A20 syngeneic mouse tumor models. It adequately captured the time profiles of intratumoral Treg and Teff and serum DTA-1.mIgG2a and soluble GITR concentrations in both mouse models, and described the response differences between the two models. The QSP model provides a quantitative understanding of the trade-off between maximizing Treg depletion versus Teff agonism, and offers insights to optimize drug design and dose regimen.

TNF receptor-related factor 3 inactivation promotes the development of intrahepatic cholangiocarcinoma through NF-κB-inducing kinase-mediated hepatocyte transdifferentiation.

BACKGROUND AND AIMS: Intrahepatic cholangiocarcinoma (ICC) is a deadly but poorly understood disease, and its treatment options are very limited. The aim of this study was to identify the molecular drivers of ICC and search for therapeutic targets. APPROACH AND RESULTS: We performed a Sleeping Beauty transposon-based in vivo insertional mutagenesis screen in liver-specific Pten -deficient mice and identified TNF receptor-related factor 3 ( Traf3 ) as the most significantly mutated gene in murine ICCs in a loss-of-function manner. Liver-specific Traf3 deletion caused marked cholangiocyte overgrowth and spontaneous development of ICC in Pten knockout and KrasG12D mutant mice. Hepatocyte-specific, but not cholangiocyte-specific, Traf3 -deficient and Pten -deficient mice recapitulated these phenotypes. Lineage tracing and single-cell RNA sequencing suggested that these ICCs were derived from hepatocytes through transdifferentiation. TRAF3 and PTEN inhibition induced a transdifferentiation-like phenotype of hepatocyte-lineage cells into proliferative cholangiocytes through NF-κB-inducing kinase (NIK) up-regulation in vitro. Intrahepatic NIK levels were elevated in liver-specific Traf3 -deficient and Pten -deficient mice, and NIK inhibition alleviated cholangiocyte overgrowth. In human ICCs, we identified an inverse correlation between TRAF3 and NIK expression, with low TRAF3 or high NIK expression associated with poor prognosis. Finally, we showed that NIK inhibition by a small molecule inhibitor or gene silencing suppressed the growth of multiple human ICC cells in vitro and ICC xenografts in vivo. CONCLUSIONS: TRAF3 inactivation promotes ICC development through NIK-mediated hepatocyte transdifferentiation. The oncogenic TRAF3-NIK axis may be a potential therapeutic target for ICC.