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Supplementary figure legend

Supplementary Figure 1: Murine SAR expression and immunophenotyping of transduced T cells

Supplementary Figure 5: Effect of pre-activated SAR T cells on hepatocellular carcinoma and glioblastoma cells


Purpose:Genetically engineered T cells are powerful anticancer treatments but are limited by safety and specificity issues. We herein describe an MHC-unrestricted modular platform combining autologous T cells, transduced with a targetable synthetic agonistic receptor (SAR), with bispecific antibodies (BiAb) that specifically recruit and activate T cells for tumor killing.Experimental Design:BiAbs of different formats were generated by recombinant expression. T cells were retrovirally transduced with SARs. T-cell activation, proliferation, differentiation, and T-cell–induced lysis were characterized in three murine and human tumor models in vitro and in vivo.Results:Murine T cells transduced with SAR composed of an extracellular domain EGFRvIII fused to CD28 and CD3ζ signaling domains could be specifically recruited toward murine tumor cells expressing EpCAM by anti-EGFRvIII × anti-EpCAM BiAb. BiAb induced selective antigen-dependent activation, proliferation of SAR T cells, and redirected tumor cell lysis. Selectivity was dependent on the monovalency of the antibody for EGFRvIII. We identified FAS ligand as a major mediator of killing utilized by the T cells. Similarly, human SAR T cells could be specifically redirected toward mesothelin-expressing human pancreatic cancer cells. In vivo, treatment with SAR T cells and BiAb mediated antitumoral activity in three human pancreatic cancer cell xenograft models. Importantly, SAR activity, unlike CAR activity, was reversible in vitro and in vivo.Conclusions:We describe a novel ACT platform with antitumor activity in murine and human tumor models with a distinct mode of action that combines adoptive T-cell therapy with bispecific antibodies.

Supplementary Figure 4: Human SAR T cells are specifically stimulated by anti-human mesothelin x anti-EGFRv3 2 + 1 BiAb and redirect lysis to mesothelin+ target cells in vitro and in vivo

Supplementary Figure 3: In contrast to SAR T cells, CAR T cells rely on the release of perforin for efficient killing.

Supplementary Figure 2: Soluble and bound EGFR ligands do not trigger unwanted SAR T cell activation, while antibodies monovalent and bivalent for SAR can trigger T cell activation to the same extent.

Major depressive disorder (MDD) is one of the most severe global health problems with millions of people affected, however, the mechanisms underlying this disorder is still poorly understood. Genome-wide association studies have highlighted a link between the neutral amino acid transporter SLC6A15 and MDD. Additionally, a number of preclinical studies support the function of this transporter in modulating levels of brain neurotransmitters, stress system regulation and behavioural phenotypes related to MDD. However, the molecular and functional mechanisms involved in this interaction are still unresolved. Therefore, to investigate the effects of the SLC6A15 transporter, we used hippocampal tissue from Slc6a15-KO and wild-type mice, together with several in-vitro assays in primary hippocampal neurons. Utilizing a proteomics approach we identified differentially regulated proteins that formed a regulatory network and pathway analysis indicated significantly affected cellular domains, including metabolic, mitochondrial and structural functions. Furthermore, we observed reduced release probability at glutamatergic synapses, increased mitochondrial function, higher GSH/GSSG redox ratio and an improved neurite outgrowth in primary neurons lacking SLC6A15. In summary, we hypothesize that by controlling the intracellular concentrations of neutral amino acids, SLC6A15 affects mitochondrial activity, which could lead to alterations in neuronal structure and activity. These data provide further indication that a pharmacological or genetic reduction of SLC6A15 activity may indeed be a promising approach for antidepressant therapy.

Forced expression of C-X-C chemokine receptor type 6 in antigen-specific T cells enhanced the recognition and lysis of pancreatic cancer cells and the efficacy of adoptive cell therapy for pancreatic cancer.The efficacy of adoptive cell therapy for solid tumours is hampered by the poor accumulation of the transferred T cells in tumour tissue. Here, we show that forced expression of C-X-C chemokine receptor type 6 (whose ligand is highly expressed by human and murine pancreatic cancer cells and tumour-infiltrating immune cells) in antigen-specific T cells enhanced the recognition and lysis of pancreatic cancer cells and the efficacy of adoptive cell therapy for pancreatic cancer. In mice with subcutaneous pancreatic tumours treated with T cells with either a transgenic T-cell receptor or a murine chimeric antigen receptor targeting the tumour-associated antigen epithelial cell adhesion molecule, and in mice with orthotopic pancreatic tumours or patient-derived xenografts treated with T cells expressing a chimeric antigen receptor targeting mesothelin, the T cells exhibited enhanced intratumoral accumulation, exerted sustained anti-tumoral activity and prolonged animal survival only when co-expressing C-X-C chemokine receptor type 6. Arming tumour-specific T cells with tumour-specific chemokine receptors may represent a promising strategy for the realization of adoptive cell therapy for solid tumours.

Purpose: Genetically engineered T cells are powerful anticancer treatments but are limited by safety and specificity issues. We herein describe an MHC-unrestricted modular platform combining autologous T cells, transduced with a targetable synthetic agonistic receptor (SAR), with bispecific antibodies (BiAb) that specifically recruit and activate T cells for tumor killing. Experimental Design: BiAbs of different formats were generated by recombinant expression. T cells were retrovirally transduced with SARs. T-cell activation, proliferation, differentiation, and T-cell–induced lysis were characterized in three murine and human tumor models in vitro and in vivo. Results: Murine T cells transduced with SAR composed of an extracellular domain EGFRvIII fused to CD28 and CD3ζ signaling domains could be specifically recruited toward murine tumor cells expressing EpCAM by anti-EGFRvIII × anti-EpCAM BiAb. BiAb induced selective antigen-dependent activation, proliferation of SAR T cells, and redirected tumor cell lysis. Selectivity was dependent on the monovalency of the antibody for EGFRvIII. We identified FAS ligand as a major mediator of killing utilized by the T cells. Similarly, human SAR T cells could be specifically redirected toward mesothelin-expressing human pancreatic cancer cells. In vivo, treatment with SAR T cells and BiAb mediated antitumoral activity in three human pancreatic cancer cell xenograft models. Importantly, SAR activity, unlike CAR activity, was reversible in vitro and in vivo. Conclusions: We describe a novel ACT platform with antitumor activity in murine and human tumor models with a distinct mode of action that combines adoptive T-cell therapy with bispecific antibodies.

Dimethyl sulfoxide (DMSO) is a polar organic solvent used in a wide range of biological applications. DMSO is routinely used as a cryoprotectant for long-term cell freezing as well as to dissolve peptides and drugs for immune cell functional assays. Here, human CD4

Selenoproteins are rare proteins among all kingdoms of life containing the 21 st amino acid, selenocysteine. Selenocysteine resembles cysteine, differing only by the substitution of selenium for sulfur. Yet the actual advantage of selenolate- versus thiolate-based catalysis has remained enigmatic, as most of the known selenoproteins also exist as cysteine-containing homologs. Here, we demonstrate that selenolate-based catalysis of the essential mammalian selenoprotein GPX4 is unexpectedly dispensable for normal embryogenesis. Yet the survival of a specific type of interneurons emerges to exclusively depend on selenocysteine-containing GPX4, thereby preventing fatal epileptic seizures. Mechanistically, selenocysteine utilization by GPX4 confers exquisite resistance to irreversible overoxidation as cells expressing a cysteine variant are highly sensitive toward peroxide-induced ferroptosis. Remarkably, concomitant deletion of all selenoproteins in Gpx4 cys/cys cells revealed that selenoproteins are dispensable for cell viability provided partial GPX4 activity is retained. Conclusively, 200 years after its discovery, a specific and indispensable role for selenium is provided. The trace element selenium protects a critical population of interneurons from ferroptotic cell death.

Dimethyl sulfoxide (DMSO) is a polar organic solvent used in a wide range of biological applications. DMSO is routinely used as a cryoprotectant for long-term cell freezing as well as to dissolve peptides and drugs for immune cell functional assays. Here, human CD4(+) T cell activation, cytokine production, proliferation, and metabolism were investigated after stimulation in the presence of 0.01% to 1%, DMSO, representing concentrations commonly used in vitro. Surface expression of the activation markers CD69, CD25 and CD154 after polyclonal activation of CD4(+) T cells was inhibited by 0.25% or higher concentrations of DMSO. The frequencies of IL-21(+), IL-4(+), and IL-22(+) CD4(+) T cells, following polyclonal activation were variably inhibited by DMSO at concentrations ranging from 0.25% to 1%, whereas IFN gamma(+) cells were unaffected. CD4(+) T cell proliferation after anti-CD3 or antigen stimulation was inhibited by 0.5% DMSO and abolished by 1% DMSO. After polyclonal stimulation, glucose uptake was inhibited in the presence of 1% DMSO, but only minor effects on CD4+ T cell respiration were observed. Consistent with the immune effects, the gene expression of early signaling and activation pathways were inhibited in CD4+ T cells in the presence of 1% DMSO. Our study revealed that DMSO at concentrations generally used for in vitro studies of T cells impacts multiple features of T cell function. Therefore, we urge care when adding DMSO-containing preparations to T cell cultures.

In pancreatic β-cells, mitochondrial bioenergetics control glucose-stimulated insulin secretion. Mitochondrial dynamics are generally associated with quality control, maintaining the functionality of bioenergetics. By acute pharmacological inhibition of mitochondrial fission protein

Brown adipose tissue (BAT)-dependent thermogenesis and its suggested augmenting hormone, FGF21, are potential therapeutic targets in current obesity and diabetes research. Here, we studied the role of UCP1 and FGF21 for metabolic homeostasis in the cold and dissected underlying molecular mechanisms using UCP1-FGF21 double-knockout mice. We report that neither UCP1 nor FGF21, nor even compensatory increases of FGF21 serum levels in UCP1 knockout mice, are required for defense of body temperature or for maintenance of energy metabolism and body weight. Remarkably, cold-induced browning of inguinal white adipose tissue (iWAT) is FGF21 independent. Global RNA sequencing reveals major changes in response to UCP1- but not FGF21-ablation in BAT, iWAT, and muscle. Markers of mitochondrial failure and inflammation are observed in BAT, but in particular the enhanced metabolic reprogramming in iWAT supports the thermogenic role of UCP1 and excludes an important thermogenic role of endogenous FGF21 in normal cold acclimation.

In pancreatic β-cells, mitochondrial bioenergetics control glucose-stimulated insulin secretion. Mitochondrial dynamics are generally associated with quality control, maintaining the functionality of bioenergetics. By acute pharmacological inhibition of mitochondrial fission protein Drp1, we demonstrate in this study that mitochondrial fission is necessary for glucose-stimulated insulin secretion in mouse and human islets. We confirm that genetic silencing of Drp1 increases mitochondrial proton leak in MIN6 cells. However, our comprehensive analysis of pancreatic islet bioenergetics reveals that Drp1 does not control insulin secretion via its effect on proton leak but instead via modulation of glucose-fueled respiration. Notably, pyruvate fully rescues the impaired insulin secretion of fission-deficient β-cells, demonstrating that defective mitochondrial dynamics solely affect substrate supply upstream of oxidative phosphorylation. The present findings provide novel insights into how mitochondrial dysfunction may cause pancreatic β-cell failure. In addition, the results will stimulate new thinking in the intersecting fields of mitochondrial dynamics and bioenergetics, as treatment of defective dynamics in mitochondrial diseases appears to be possible by improving metabolism upstream of mitochondria.

Adoptive T cell therapy, namely chimeric antigen receptor (CAR) T cell therapy has been a groundbreaking and effective treatment of relapsed or refractory haematological malignancies. Still, many patients do not respond or relapse with treatment-resistant disease. Additionally, toxicities such as cytokine release syndrome remain problematic. Cancer heterogeneity, beyond cancer types and inter-patient differences, is present within every individual patient. This heterogeneity, especially in the context of solid tumors, has meant that targeted immunotherapies have fared relatively poorly, creating a need for a modular platform with a capacity to target multiple antigens simultaneously and/or sequentially. Likewise, treatment-related toxicities have limited the therapeutic efficacy and breadth of patient selection. To tackle these caveats through a modular and controllable approach, we equipped T cells with synthetic agonistic receptors (SARs) that are only activated when a tumor-associated antigen and a cross-linking bispecific antibody (BiAb) specific for both SAR T cell and tumor cell are also present. The SAR itself is constituted of an inert extracellular domain in the form of EGFRvIII, that is fused to the T cell activating domains CD28 and CD3ζ. The BiAb employed is a trivalent CrossMab, with two binding arms (2 x Fab) for the tumor-associated antigen (mesothelin), and one binding arm for the SAR receptor (EGFRvIII). We showed that BiAb triggering of the SAR is conditional upon the binding of the second BiAb specificity. What is particularly advantageous with this approach is that T cell activation may only occur when the BiAb is present and in proximity to the antibody-targeted tumor cell. This conditional T cell activation is an inherent safety feature of the platform, whereby if unwanted levels of T cell activation are observed, depletion of the BiAb from the system could result in the reversal of said activation, thus managing the potential toxicity. This work was able to determine the validity and efficacy of the approach. Through the generation of several human pancreatic cancer models, and extensive in vitro and in vivo testing, the platform could be characterized. Its translational relevance and significance as a next-generation adoptive T cell therapy with the potential to plug some gaping pitfalls of current ACT approaches were also shown.

Objective Circulating fibroblast growth factor 21 (FGF21) is an important auto- and endocrine player with beneficial metabolic effects on obesity and diabetes. In humans, thermogenic brown adipose tissue (BAT) was recently suggested as a source of FGF21 secretion during cold exposure. Here, we aim to clarify the role of UCP1 and ambient temperature in the regulation of FGF21 in mice. Methods Wildtype (WT) and UCP1-knockout (UCP1 KO) mice, the latter being devoid of BAT-derived non-shivering thermogenesis, were exposed to different housing temperatures. Plasma metabolites and FGF21 levels were determined, gene expression was analyzed by qPCR, and tissue histology was performed with adipose tissue. Results At thermoneutrality, FGF21 gene expression and serum levels were not different between WT and UCP1 KO mice. Cold exposure led to highly increased FGF21 serum levels in UCP1 KO mice, which were reflected in increased FGF21 gene expression in adipose tissues but not in liver and skeletal muscle. Ex vivo secretion assays revealed FGF21 release only from BAT, progressively increasing with decreasing ambient temperatures. In association with increased FGF21 serum levels in the UCP1 KO mouse, typical FGF21-related serum metabolites and inguinal white adipose tissue morphology and thermogenic gene expression were altered. Conclusions Here we show that the genetic ablation of UCP1 increases FGF21 gene expression in adipose tissue. The removal of adaptive nonshivering thermogenesis renders BAT a significant source of endogenous FGF21 under thermal stress. Thus, the thermogenic competence of BAT is not a requirement for FGF21 secretion. Notably, high endogenous FGF21 levels in UCP1-deficient models and subjects may confound pharmacological FGF21 treatments., Highlights • Genetic ablation of UCP1 increases FGF21 gene expression in adipose tissue. • The removal of adaptive nonshivering thermogenesis renders BAT a significant source of endogenous FGF21 under thermal stress. • The thermogenic competence of BAT is not a requirement for FGF21 secretion.

Obesity and type 2 diabetes are associated with metabolic defects and adipose tissue inflammation. Foxp3(+) regulatory Tcells (Tregs) control tissue homeostasis by counteracting local inflammation. However, if and how Tcells interlink environmental influences with adipocyte function remains unknown. Here, we report that enhancing sympathetic tone by cold exposure, beta3-adrenergic receptor (ADRB3) stimulation or a short-term high-calorie diet enhances Treg induction invitro and invivo. CD4(+) Tcell proteomes revealed higher expression of Foxp3 regulatory networks in response to cold or ADRB3 stimulation invivo reflecting Treg induction. Specifically, Ragulator-interacting protein C17orf59, which limits mTORC1 activity, was upregulated in CD4(+) Tcells by either ADRB3 stimulation or cold exposure, suggesting contribution to Treg induction. By loss- and gain-of-function studies, including Treg depletion and transfers invivo, we demonstrated that a Tcell-specific Stat6/Pten axis links cold exposure or ADRB3 stimulation with Foxp3(+) Treg induction and adipose tissue function. Our findings offer a new mechanistic model in which tissue-specific Tregs maintain adipose tissue function.