On the TRAIL of Better Therapies: Understanding TNFRSF Structure-Function

Therapeutic targets for age-related macular degeneration: proteome-wide Mendelian randomization and colocalization analyses

Background

Currently, effective therapeutic drugs for age-related macular degeneration (AMD) are urgently needed, and it is crucial to explore new treatment targets. The proteome is indispensable for exploring disease targets, so we conducted a Mendelian randomization (MR) of the proteome to identify new targets for AMD and its related subtypes.

Methods

The plasma protein level data used in this study were obtained from two large-scale studies of protein quantitative trait loci (pQTL), comprising 35,559 and 54,219 samples, respectively. The expression quantitative trait loci (eQTL) data were sourced from eQTLGen and GTEx Version 8. The discovery set for AMD data and subtypes was derived from the FinnGen study, consisting of 9,721 AMD cases and 381,339 controls, 5,239 wet AMD cases and 273,920 controls, and 6,651 dry AMD cases and 272,504 controls. The replication set for AMD data was obtained from the study by Winkler TW et al., comprising 14,034 cases and 91,234 controls. Summary Mendelian randomization (SMR) analysis was employed to assess the association between QTL data and AMD and its subtypes, while colocalization analysis was performed to determine whether they share causal variants. Additionally, chemical exploration and molecular docking were utilized to validate potential drugs targeting the identified proteins.

Results

SMR and colocalization analysis jointly identified risk-associated proteins for AMD and its subtypes, including 5 proteins (WARS1, BRD2, IL20RB, TGFB1, TNFRSF10A) associated with AMD, 2 proteins (WARS1, IL20RB) associated with Dry-AMD, and 9 proteins (COL10A1, WARS1, VTN, SDF2, LBP, CD226, TGFB1, TNFRSF10A, CSF2) associated with Wet-AMD. The results revealed potential therapeutic chemicals, and molecular docking indicated a good binding between the chemicals and protein structures.

Conclusion

Proteome-wide MR have identified risk-associated proteins for AMD and its subtypes, suggesting that these proteins may serve as potential therapeutic targets worthy of further clinical investigation.

TNF-Related Apoptosis-Inducing Ligand: Non-Apoptotic Signalling

TNF-related apoptosis-inducing ligand (TRAIL or Apo2 or TNFSF10) belongs to the TNF superfamily. When bound to its agonistic receptors, TRAIL can induce apoptosis in tumour cells, while sparing healthy cells. Over the last three decades, this tumour selectivity has prompted many studies aiming at evaluating the anti-tumoral potential of TRAIL or its derivatives. Although most of these attempts have failed, so far, novel formulations are still being evaluated. However, emerging evidence indicates that TRAIL can also trigger a non-canonical signal transduction pathway that is likely to be detrimental for its use in oncology. Likewise, an increasing number of studies suggest that in some circumstances TRAIL can induce, via Death receptor 5 (DR5), tumour cell motility, potentially leading to and contributing to tumour metastasis. While the pro-apoptotic signal transduction machinery of TRAIL is well known from a mechanistic point of view, that of the non-canonical pathway is less understood. In this study, we the current state of knowledge of TRAIL non-canonical signalling.

Immune activation of the p75 neurotrophin receptor: implications in neuroinflammation

Despite structural similarity with other tumor necrosis factor receptor superfamily (TNFRSF) members, the p75 neurotrophin receptor (p75NTR, TNFR16) mediates pleiotropic biological functions not shared with other TNFRs. The high level of p75NTR expression in the nervous system instead of immune cells, its utilization of co-receptors, and its interaction with soluble dimeric, rather than soluble or cell-tethered trimeric ligands are all characteristics which distinguish it from most other TNFRs. Here, we compare these attributes to other members of the TNFR superfamily. In addition, we describe the recent evolutionary adaptation in B7-1 (CD80), an immunoglobulin (Ig) superfamily member, which allows engagement to neuronally-expressed p75NTR. B7-1-mediated binding to p75NTR occurs in humans and other primates, but not lower mammals due to specific sequence changes that evolved recently in primate B7-1. This discovery highlights an additional mechanism by which p75NTR can respond to inflammatory cues and trigger synaptic elimination in the brain through engagement of B7-1, which was considered to be immune-restricted. These observations suggest p75NTR does share commonality with other immune co-modulatory TNFR family members, by responding to immunoregulatory cues. The evolution of primate B7-1 to bind and elicit p75NTR-mediated effects on neuronal morphology and function are discussed in relationship to immune-driven modulation of synaptic actions during injury or inflammation.

Respiratory syncytial virus-approved mAb Palivizumab as ligand for anti-idiotype nanobody-based synthetic cytokine receptors

Synthetic cytokine receptors can modulate cellular functions based on an artificial ligand to avoid off-target and/or unspecific effects. However, ligands that can modulate receptor activity so far have not been used clinically because of unknown toxicity and immunity against the ligands. Here, we developed a fully synthetic cytokine/cytokine receptor pair based on the antigen-binding domain of the respiratory syncytial virus-approved mAb Palivizumab as a synthetic cytokine and a set of anti-idiotype nanobodies (AIPVHH) as synthetic receptors. Importantly, Palivizumab is neither cross-reactive with human proteins nor immunogenic. For the synthetic receptors, AIPVHH were fused to the activating interleukin-6 cytokine receptor gp130 and the apoptosis-inducing receptor Fas. We found that the synthetic cytokine receptor AIPVHHgp130 was efficiently activated by dimeric Palivizumab single-chain variable fragments. In summary, we created an in vitro nonimmunogenic full-synthetic cytokine/cytokine receptor pair as a proof of concept for future in vivo therapeutic strategies utilizing nonphysiological targets during immunotherapy.

Development of a 1:1-binding biparatopic anti-TNFR2 antagonist by reducing signaling activity through epitope selection

Conventional bivalent antibodies against cell surface receptors often initiate unwanted signal transduction by crosslinking two antigen molecules. Biparatopic antibodies (BpAbs) bind to two different epitopes on the same antigen, thus altering crosslinking ability. In this study, we develop BpAbs against tumor necrosis factor receptor 2 (TNFR2), which is an attractive immune checkpoint target. Using different pairs of antibody variable regions specific to topographically distinct TNFR2 epitopes, we successfully regulate the size of BpAb-TNFR2 immunocomplexes to result in controlled agonistic activities. Our series of results indicate that the relative positions of the two epitopes recognized by the BpAb are critical for controlling its signaling activity. One particular antagonist, Bp109-92, binds TNFR2 in a 1:1 manner without unwanted signal transduction, and its structural basis is determined using cryo-electron microscopy. This antagonist suppresses the proliferation of regulatory T cells expressing TNFR2. Therefore, the BpAb format would be useful in designing specific and distinct antibody functions.

The benefits of clustering in TNF receptor superfamily signaling

The tumor necrosis factor (TNF) receptor superfamily is a structurally and functionally related group of cell surface receptors that play crucial roles in various cellular processes, including apoptosis, cell survival, and immune regulation. This review paper synthesizes key findings from recent studies, highlighting the importance of clustering in TNF receptor superfamily signaling. We discuss the underlying molecular mechanisms of signaling, the functional consequences of receptor clustering, and potential therapeutic implications of targeting surface structures of receptor complexes.

Hepatocellular carcinoma cell differentiation trajectory predicts immunotherapy, potential therapeutic drugs, and prognosis of patients

The aim of this study is to explore a novel classification and investigate the clinical significance of hepatocellular carcinoma (HCC) cells. We analyzed integrated single-cell RNA sequencing and bulk RNA-seq data obtained from HCC samples. Cell trajectory analysis divided HCC cells into three subgroups with different differentiation states: state 1 was closely related to phosphoric ester hydrolase activity, state 2 was involved in eukaryotic initiation factor 4E binding, translation regulator activity and ribosome, and state 3 was associated with oxidoreductase activity and metabolism. Three molecular classes based on HCC differentiation-related genes (HDRGs) from HCC samples were identified, which revealed immune checkpoint gene expression and overall survival (OS) of HCC patients. Moreover, a prognostic risk scoring (RS) model was generated based on eight HDRGs, and the results showed that the OS of the high-risk group was worse than that of the low-risk group. Further, potential therapeutic drugs were screened out based on eight prognostic RS-HDRGs. This study highlights the importance of HCC cell differentiation in immunotherapy, clinical prognosis, and potential molecular-targeted drugs for HCC patients, and proposes a direction for the development of individualized treatments for HCC.

Dysregulation of a lncRNA within the TNFRSF10A locus activates cell death pathways

TNFRSF10A (tumor necrosis factor receptor superfamily member 10A) encodes a cell surface receptor protein involved in apoptotic, necroptotic, and inflammatory pathways. Dysregulation of TNFRSF10A has been implicated in sensitization to apoptosis and to the development of multiple diseases, yet little is known of the AC100861.1 long noncoding RNA (lncRNA) that lies head-to-head with TNFRSF10A. Given its genomic positioning, we sought to investigate the function of AC100861.1, focusing on its potential relationship with TNFRSF10A and the role it may play in death receptor signaling. Using knockdown and overexpression strategies, we probed cell viability and examined transcript and protein-level changes in key genes involved in apoptosis, necroptosis, and inflammation. Decreased cell viability was observed upon TNFRSF10A overexpression, regardless of whether the cells were subjected to the chemical stressor tunicamycin. Similarly, overexpression of AC100861.1 led to increased cell death, with a further increase observed under conditions of cellular stress. Knockdown of TNFRSF10A increased cell death only when the cells were stressed, and AC100861.1 knockdown exhibited no effect on cell death. Neither knockdown nor overexpression of either of these genes greatly affected the expression of the other. Manipulating AC100861.1, however, led to marked changes in the expression of genes involved in necroptosis and inflammatory cell-signaling pathways. Additionally, RNA fluorescence in situ hybridization (RNA-FISH) revealed that the AC100861.1 transcript is localized primarily to the cytoplasm. Together, these data suggest that AC100861.1 may have a role in regulating necroptotic and inflammatory signaling pathways and that this function is separate from changes in TNFRSF10A expression. Given the importance of this genomic locus for cell survival, these data provide insight into the function of a poorly understood lncRNA with potential implications regarding disease pathology and treatment.

Construction and comprehensive analysis of a curoptosis-related lncRNA signature for predicting prognosis and immune response in cervical cancer

Cuproptosis (copper-ion-dependent cell death) is an unprogrammed cell death, and intracellular copper accumulation, causing copper homeostasis imbalance and then leading to increased intracellular toxicity, which can affect the rate of cancer cell growth and proliferation. This study aimed to create a newly cuproptosis-related lncRNA signature that can be used to predict survival and immunotherapy in patients with cervical cancer, but also to predict prognosis in patients treated with radiotherapy and may play a role in predicting radiosensitivity. First of all, we found lncRNAs associated with cuproptosis between cervical cancer tumor tissues and normal tissues. By LASSO-Cox analysis, overlapping lncRNAs were then used to construct lncRNA signatures associated with cuproptosis, which can be used to predict the prognosis of patients, especially the prognosis of radiotherapy patients, ROC curves and PCA analysis based on cuprotosis-related lncRNA signature and clinical signatures were developed and demonstrated to have good predictive potential. In addition, differences in immune cell subset infiltration and differences in immune checkpoint expression between high-risk and low-risk score groups were analyzed, and we investigated the relationship between this signature and tumor mutation burden. In summary, we constructed a lncRNA prediction signature associated with cuproptosis. This has important clinical implications, including improving the predictive value of cervical cancer patients and providing a biomarker for cervical cancer.

TRAF trimers form immune signalling networks via RING domain dimerization

For many inflammatory cytokines, the response elicited is dependent on the recruitment of the tumour necrosis factor receptor-associated factor (TRAF) family of adaptor proteins. All TRAF proteins have a trimeric C-terminal TRAF domain, while at the N-terminus most TRAFs have a RING domain that forms dimers. The symmetry mismatch of the N- and C-terminal halves of TRAF proteins means that when receptors cluster, it is presumed that RING dimers connect TRAF trimers to form a network. Here, using purified TRAF6 proteins, we provide direct evidence in support of this model, and we show that TRAF6 trimers bind Lys63-linked ubiquitin chains to promote their processive assembly. This study provides critical evidence in support of TRAF trimers as key players in signalling.

FcγRs and Their Relevance for the Activity of Anti-CD40 Antibodies

Inhibitory targeting of the CD40L-CD40 system is a promising therapeutic option in the field of organ transplantation and is also attractive in the treatment of autoimmune diseases. After early complex results with neutralizing CD40L antibodies, it turned out that lack of Fcγ receptor (FcγR)-binding is the crucial factor for the development of safe inhibitory antibodies targeting CD40L or CD40. Indeed, in recent years, blocking CD40 antibodies not interacting with FcγRs, has proven to be well tolerated in clinical studies and has shown initial clinical efficacy. Stimulation of CD40 is also of considerable therapeutic interest, especially in cancer immunotherapy. CD40 can be robustly activated by genetically engineered variants of soluble CD40L but also by anti-CD40 antibodies. However, the development of CD40L-based agonists is biotechnologically and pharmacokinetically challenging, and anti-CD40 antibodies typically display only strong agonism in complex with FcγRs or upon secondary crosslinking. The latter, however, typically results in poorly developable mixtures of molecule species of varying stoichiometry and FcγR-binding by anti-CD40 antibodies can elicit unwanted side effects such as antibody-dependent cellular cytotoxicity (ADCC) or antibody-dependent cellular phagocytosis (ADCP) of CD40 expressing immune cells. Here, we summarize and compare strategies to overcome the unwanted target cell-destroying activity of anti-CD40-FcγR complexes, especially the use of FcγR type-specific mutants and the FcγR-independent cell surface anchoring of bispecific anti-CD40 fusion proteins. Especially, we discuss the therapeutic potential of these strategies in view of the emerging evidence for the dose-limiting activities of systemic CD40 engagement.

A Signature Based on Costimulatory Molecules for the Assessment of Prognosis and Immune Characteristics in Patients With Stomach Adenocarcinoma

Although costimulatory molecules have been shown to boost antitumor immune responses, their significance in stomach adenocarcinoma (STAD) remains unknown. The purpose of this study was to examine the gene expression patterns of costimulatory molecule genes in patients with STAD and develop a predictive signature to aid in therapy selection and outcome prediction. We used 60 costimulatory family genes from prior research to conduct the first complete costimulatory molecular analysis in patients with STAD. In the two study groups, consensus clustering analysis based on these 60 genes indicated unique distribution patterns and prognostic differences. Using the least absolute shrinkage and selection operator and Cox regression analysis, we identified nine costimulatory molecular gene pairs (CMGPs) with prognostic value. With these nine CMGPs, we were able to develop a costimulatory molecule-related prognostic signature that performed well in an external dataset. For the patients with STAD, the signature was proven to be a risk factor independent of the clinical characteristics, indicating that this signature may be employed in conjunction with clinical considerations. A further connection between the signature and immunotherapy response was discovered. The patients with high mutation rates, an abundance of infiltrating immune cells, and an immunosuppressive milieu were classified as high-risk patients. It is possible that these high-risk patients have a better prognosis for immunotherapy since they have higher cytolytic activity scores and immunophenoscores of CTLA4 and PD-L1/PD-L2 blockers. Therefore, our signature may help clinicians in assessing patient prognosis and developing treatment plans.

TRAIL protects the immature lung from hyperoxic injury

The hyperoxia-induced pro-inflammatory response and tissue damage constitute pivotal steps leading to bronchopulmonary dysplasia (BPD) in the immature lung. The pro-inflammatory cytokines are considered attractive candidates for a directed intervention but the complex interplay between inflammatory and developmental signaling pathways requires a comprehensive evaluation before introduction into clinical trials as studied here for the death inducing ligand TRAIL. At birth and during prolonged exposure to oxygen and mechanical ventilation, levels of TRAIL were lower in tracheal aspirates of preterm infants <29 weeks of gestation which developed moderate/severe BPD. These findings were reproduced in the newborn mouse model of hyperoxic injury. The loss of TRAIL was associated with increased inflammation, apoptosis induction and more pronounced lung structural simplification after hyperoxia exposure for 7 days while activation of NFκB signaling during exposure to hyperoxia was abrogated. Pretreatment with recombinant TRAIL rescued the developmental distortions in precision cut lung slices of both wildtype and TRAIL^-/- mice exposed to hyperoxia. Of importance, TRAIL preserved alveolar type II cells, mesenchymal progenitor cells and vascular endothelial cells. In the situation of TRAIL depletion, our data ascribe oxygen toxicity a more injurious impact on structural lung development. These data are not surprising taking into account the diverse functions of TRAIL and its stimulatory effects on NFκB signaling as central driver of survival and development. TRAIL exerts a protective role in the immature lung as observed for the death inducing ligand TNF-α before.

The Roles of TNF Signaling Pathways in Metabolism of Bone Tumors

The metabolism of bone tumors is extraordinarily complex and involves many signaling pathways and processes, including the tumor necrosis factor (TNF) signaling pathway, which consists of TNF factors and the TNF receptors that belong to the TNF receptor superfamily (TNFRSF). It is appreciated that signaling events and pathways involving TNFRSF components are essential in coordinating the functions of multiple cell types that act as a host defense network against pathogens and malignant cells, the implications of TNFRSF-related signaling pathways on bone tumor metabolism remain to be summarized, which is one of the significant obstacles to the application of TNF-related treatment modalities in the domain of bone oncology. This review will discuss and summarize the anti-tumor properties of important TNFRSF components concerning osteosarcoma, chondrosarcoma, and Ewing sarcoma.

Identification and Validation of Prognostic Related Hallmark ATP-Binding Cassette Transporters Associated With Immune Cell Infiltration Patterns in Thyroid Carcinoma

ATP-binding cassette (ABC) transporters are a large superfamily of membrane proteins that facilitate the translocation of heterogeneous substrates. Studies indicate that ABC transporters may play important roles in various carcinomas. However, the correlation between ABC transporters and immunomodulation in thyroid carcinoma (TC), as well as the prognoses for this disease, is poorly understood.TC data from The Cancer Genome Atlas (TCGA) database were used to identify prognostic hallmark ABC transporters associated with immune cell infiltration patterns via multiple bioinformatic analyses. Thereafter, quantitative real-time polymerase chain reaction (qRT-PCR) was performed to validate the expression of these selected hallmark ABC transporters in both TC and para-cancerous thyroid tissues. Of a total of 49 ABC transporters, five (ABCA8, ABCA12, ABCB6, ABCB8, and ABCC10) were identified as hallmark ABC transporters. All five were differentially expressed in TC and associated with the relapse-free survival rates of patients with TC. Immunoregulation by these five hallmark ABC transporters involved the modulation of various aspects of immune cell infiltration, such as hot or cold tumor subsets and the abundances of infiltrating immune cells, as well as specific immunomodulators and chemokines. Besides the diverse significantly correlated factors, the five hallmark ABC transporters and correlated genes were most highly enriched in plasma membrane, transporter activity, and transmembrane transport of small molecules. In addition, many chemicals, namely bisphenol A and vincristine, affected the expression of these five transporters. The qRT-PCR results of collected TC and para-cancerous thyroid tissues were consistent with those of TCGA. The findings in this study may reveal the role played by these five hallmark ABC transporters in regulating immune cell infiltration patterns in TC as well as the molecular mechanisms underlying their functions, leading to a better understanding of their potential prognostic and immunotherapeutic values.

Human Tumor Targeted Cytotoxic Mast Cells for Cancer Immunotherapy

The diversity of autologous cells being used and investigated for cancer therapy continues to increase. Mast cells (MCs) are tissue cells that contain a unique set of anti-cancer mediators and are found in and around tumors. We sought to exploit the anti-tumor mediators in MC granules to selectively target them to tumor cells using tumor specific immunoglobin E (IgE) and controllably trigger release of anti-tumor mediators upon tumor cell engagement. We used a human HER2/neu-specific IgE to arm human MCs through the high affinity IgE receptor (FcεRI). The ability of MCs to bind to and induce apoptosis of HER2/neu-positive cancer cells in vitro and in vivo was assessed. The interactions between MCs and cancer cells were investigated in real time using confocal microscopy. The mechanism of action using cytotoxic MCs was examined using gene array profiling. Genetically manipulating autologous MC to assess the effects of MC-specific mediators have on apoptosis of tumor cells was developed using siRNA. We found that HER2/neu tumor-specific IgE-sensitized MCs bound, penetrated, and killed HER2/neu-positive tumor masses in vitro. Tunneling nanotubes formed between MCs and tumor cells are described that parallel tumor cell apoptosis. In solid tumor, human breast cancer (BC) xenograft mouse models, infusion of HER2/neu IgE-sensitized human MCs co-localized to BC cells, decreased tumor burden, and prolonged overall survival without indications of toxicity. Gene microarray of tumor cells suggests a dependence on TNF and TGFβ signaling pathways leading to apoptosis. Knocking down MC-released tryptase did not affect apoptosis of cancer cells. These studies suggest MCs can be polarized from Type I hypersensitivity-mediating cells to cytotoxic cells that selectively target tumor cells and specifically triggered to release anti-tumor mediators. A strategy to investigate which MC mediators are responsible for the observed tumor killing is described so that rational decisions can be made in the future when selecting which mediators to target for deletion or those that could further polarize them to cytotoxic MC by adding other known anti-tumor agents. Using autologous human MC may provide further options for cancer therapeutics that offers a unique anti-cancer mechanism of action using tumor targeted IgE’s.

Signal Amplification in Highly Ordered Networks Is Driven by Geometry

Here, we hypothesize that, in biological systems such as cell surface receptors that relay external signals, clustering leads to substantial improvements in signaling efficiency. Representing cooperative signaling networks as planar graphs and applying Euler’s polyhedron formula, we can show that clustering may result in an up to a 200% boost in signaling amplitude dictated solely by the size and geometry of the network. This is a fundamental relationship that applies to all clustered systems regardless of its components. Nature has figured out a way to maximize the signaling amplitude in receptors that relay weak external signals. In addition, in cell-to-cell interactions, clustering both receptors and ligands may result in maximum efficiency and synchronization. The importance of clustering geometry in signaling efficiency goes beyond biological systems and can inform the design of amplifiers in nonbiological systems.

Inhibition of ADAM17 impairs endothelial cell necroptosis and blocks metastasis

Metastasis is the major cause of death in cancer patients. Circulating tumor cells need to migrate through the endothelial layer of blood vessels to escape the hostile circulation and establish metastases at distant organ sites. Here, we identified the membrane-bound metalloprotease ADAM17 on endothelial cells as a key driver of metastasis. We show that TNFR1-dependent tumor cell-induced endothelial cell death, tumor cell extravasation, and subsequent metastatic seeding is dependent on the activity of endothelial ADAM17. Moreover, we reveal that ADAM17-mediated TNFR1 ectodomain shedding and subsequent processing by the γ-secretase complex is required for the induction of TNF-induced necroptosis. Consequently, genetic ablation of ADAM17 in endothelial cells as well as short-term pharmacological inhibition of ADAM17 prevents long-term metastases formation in the lung. Thus, our data identified ADAM17 as a novel essential regulator of necroptosis and as a new promising target for antimetastatic and advanced-stage cancer therapies.

Controlled Modular Multivalent Presentation of the CD40 Ligand on P22 Virus-like Particles Leads to Tunable Amplification of CD40 Signaling

Ligands of the tumor necrosis factor superfamily (TNFSF) are appealing targets for immunotherapy research due to their integral involvement in stimulation or restriction of immune responses. TNFSF-targeted therapies are currently being developed to combat immunologically based diseases and cancer. A crucial determinant of effective TNFSF receptor binding and signaling is the trimeric quaternary structure of the ligand. Additionally, ligand multivalency is essential to propagate strong signaling in effector cells. Thus, designing a synthetic platform to display trimeric TNFSF ligands in a multivalent manner is necessary to further the understanding of ligand-receptor interactions. Viral nanocages have architectures that are amenable to genetic and chemical modifications of both their interior and exterior surfaces. Notably, the exterior surface of virus-like particles can be utilized as a platform for the modular multivalent presentation of target proteins. In this study, we build on previous efforts exploring the bacteriophage P22 virus-like particle for the exterior multivalent modular display of a potent immune-stimulating TNFSF protein, CD40 ligand (CD40L). Using a cell-based reporter system, we quantify the effects of tunable avidity on CD40 signaling by CD40L displayed on the surface of P22 nanocages. Multivalent presentation of CD40L resulted in a 53.6-fold decrease of the half maximal effective concentration (EC₅₀) compared to free CD40L, indicating higher potency. Our results emphasize the power of using P22-based biomimetics to study ligand-receptor interactions within their proper structural context, which may contribute to the development of effective immune modulators.

Transthyretin-mediated protein and peptide oligomerization for enhanced target clustering

Advances in cancer research have led to the development of new therapeutics with significant and durable responses such as immune checkpoint inhibitors. More recent therapies aim to stimulate anti-tumor immune responses by targeting the tumor necrosis factor (TNF) receptors, however this approach has been shown to require clustering of receptors in order to achieve a significant response. Here we present a perspective on using transthyretin, a naturally occurring serum protein, as a drug delivery platform to enable cross-linking independent clustering of targets. TTR forms a stable homo-tetramer with exposed termini that make TTR a highly versatile platform for generating multimeric antibody fusions to enable enhanced target clustering. Fusions with antibodies or Fabs targeting TRAILR2 were shown to have robust cytotoxic activity in vitro and in vivo in colorectal xenograft models demonstrating that TTR is a highly versatile, stable, therapeutic fusion platform that can be used with antibodies, Fabs and other bioactive fusion partners and has broad applications in oncology and infectious disease research.

Pro- and anti-apoptotic fate decisions induced by di- and trimeric synthetic cytokine receptors

Synthetic strategies to activate cytokine receptors so far only address standard dimeric cytokine receptor assemblies. The 19 ligands of the tumor necrosis factor superfamily (TNFSF), however, form noncovalent trimers and receptor trimerization is considered to be essential for receptor activation. Synthetic TNFR1, TNFR2, and Fas/CD95 receptors were activated by synthetic trimeric ligands which induced NF-κB signaling or Caspase-induced apoptosis. Albeit dimeric receptor activation did not induce synthetic TNFR1 and TNFR2 signaling, dimeric FasL induced extenuated apoptosis. Simultaneous integration of dimeric Interleukin (IL-)6 receptor gp130 and trimeric Fas as synthetic cytokine receptors in one cell enabled binary cell fate decisions, gp130-mediated proliferation or Fas-mediated apoptosis. In summary, our modular fully synthetic cytokine signaling system allows precisely orchestrated cellular responses to selectively induce pro- and anti-apoptotic signaling via canonical dimeric receptors of the IL-6 family and non-canonical trimeric receptor complexes of the TNF superfamily.

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SyCyRs induce TNFR1 or TNFR2 mediated NF-κB activation as trimers or oligomers.

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Fas-SyCyR induces Caspase-induced apoptosis as trimer and as dimer.

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Synthetic loss of function Fas-SyCyR fails to induce Caspase mediated apoptosis.

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gp130-and Fas-SyCyR in one cell enable proliferation via gp130 or apoptosis via Fas.

Identification and characterization of a tumor necrosis factor receptor like protein encoded by Cyprinid Herpesvirus 2

Virus-encoded tumor necrosis factor receptors (vTNFRs) facilitate viral escape from the host immune response during viral propagation. Cyprinid Herpesvirus-2 (CyHV-2) is a double-stranded DNA virus of alloherpesviridae family that causes great economic losses in the aquaculture industry. The present study identified and characterized a novel TNFR homolog termed ORF4 in CyHV-2. ORF4 was identified as a secreted protein and a homolog of herpesvirus entry mediator (HVEM). ORF4 localized to the cytoplasm in infected GiCF cells. ORF4 overexpression enhanced viral propagation, while downregulation of ORF4 via siRNA decreased viral propagation. ORF4 overexpression promoted GiCF proliferation, and its downregulation suppressed CyHV-2-induced apoptosis. GST-pulldown and LC-MS/MS assays identified 44 conditional binding proteins that interact with ORF4 protein, while the GST pulldown test did not support the idea that ORF4 interact with histone H3.3. Taken together, our results contribute to our understanding of the vTNFR function in alloherpesviridae pathogenesis and host immune regulation.