Biology subjects

Bekiaris, V.

Publications and source records attributed to Bekiaris, V..

7 recordsLinked to original sources

bioRxiv2025

A STAT5B-driven mouse model of hepatosplenic γδ T-cell lymphoma reveals therapeutic efficacy of JAK inhibition

Hepatosplenic T-cell lymphoma (HSTCL) is a rare and aggressive neoplasm associated with poor responses to standard chemotherapy regimens and low survival rates. No targeted therapies are available for HSTCL, and preclinical models to test new treatment options have not been established. The JAK-STAT signaling cascade is a key dysregulated pathway in HSTCL, and STAT5BN642His the most frequent somatic mutation in the disease. Here, we report on newly established clonal, murine {gamma}{delta} T-cell lymphoma cell lines initiated and driven by oncogenic STAT5BN642H, which recapitulate key immunophenotypic features, gene expression profiles and typically low cytolytic activity of patient-derived human HSTCL cells. CRISPR-Cas9 mediated knockout demonstrated growth dependence on STAT5BN642H. Murine C15 cells were allo-engrafted intravenously into both immunodeficient and immunocompetent mice to model an aggressive HSTCL-like disease at high penetrance, with recipient mice displaying hepatosplenomegaly and destructive {gamma}{delta} T cell organ infiltration, including bone marrow and blood involvement. We identified the potential of JAK inhibition as a targeted treatment strategy for HSTCL, and found the clinically approved JAK inhibitor upadacitinib to display selective anti-tumor efficacy against STAT5B-mutated HSTCL cell lines in vitro, in vivo, and in primary HSTCL patient samples. Overall, we describe the first robust STAT5B-driven preclinical model resembling features of HSTCL in an immune competent setting. This tool is expected to accelerate the study of HSTCL disease mechanisms and the testing of novel therapies. Our data further present the JAK inhibitor upadacitinib as a promising targeted treatment option for STAT5B-mutated HSTCL.

cancer biology↗

bioRxiv2025

Checkpoint receptors in circulating γδ T cells can discern the outcome of cancer immunotherapy

Gamma delta ({gamma}{delta}) T cells are innate-like lymphocytes that in humans can be broadly classified into two main subtypes based on their unique TCR{delta} chain, V{delta}1 and V{delta}2. Both subsets have potent anti-tumor properties and the presence of V{delta}1 cells in the tumor is often associated with positive prognosis. Herein, we investigated the molecular interplay between immune checkpoint receptors (ICRs), IC blockade (ICB) therapy and {gamma}{delta} T cells. We show that ICRs display differential expression and regulation by the JAK-STAT pathway in circulating V{delta}1 and V{delta}2 cells and identify constitutive (e.g. TIGIT, PD-1) and inducible (e.g. TIM-3, LAG-3, CTLA-4) ICRs. In melanoma, V{delta}1 cells, especially in patients who did not respond to ICB or required combination therapy, expressed high levels of ICR, TOX and inhibitory killer Ig-like receptors (KIR) transcripts, reminiscent of an exhaustion transcriptional signature. At the same time all {gamma}{delta} T cells had a prominent downregulation in AP-1 transcription factors. Patient derived cells were functionally competent, although induction of LAG-3 and CTLA-4 was impaired. In the context of anti-PD-1 monotherapy, V{delta}1 cells specifically bound high levels of therapeutic antibody but only in patients who responded to treatment, revealing a potential new prognostic marker for evaluating the efficacy of ICB therapy. Finally, expression of KIR genes in V{delta}1 cells was downregulated in response to successful ICB therapy. Collectively, our data indicate an intricate relationship between ICRs, putatively also KIRs, and {gamma}{delta} T cells and reveal novel approaches by which these cells can be harnessed in order to discern or improve cancer immunotherapy.

immunology↗

bioRxiv2023

IL-27 maintains cytotoxic Ly6C+ gamma delta T cells that arise from immature precursors

In mice, {gamma}{delta} T cells that express the co-stimulatory molecule, CD27, are committed to the IFN{gamma}-producing lineage in the thymus, and in the periphery, these cells play a critical role in host defence and anti-tumor immunity. Unlike {beta} T cells that rely on MHC-presented peptides to drive their terminal differentiation, it is unclear whether MHC-unrestricted {gamma}{delta} T cells undergo further functional maturation after exiting the thymus. Here, we provide evidence of phenotypic and functional diversity within peripheral IFN{gamma}-producing {gamma}{delta} T cells. We found that immature CD27+Ly6C-- cells convert into mature CD27+Ly6C+ cells, and these mature cells control cancer progression while the immature cells cannot. The gene signatures of these two subsets were highly analogous to human immature and mature {gamma}{delta} T cells, indicative of conservation across species. We show that IL-27 supports the cytotoxic phenotype and function of mouse CD27+Ly6C+ cells and human V{delta}2+ cells, while IL-27 is dispensable for mouse CD27+Ly6C-- cells and human V{delta}1+ cells. These data reveal increased complexity within IFN{gamma}-producing {gamma}{delta} T cells, comprising of immature and terminally differentiated subsets, that offer new insights into unconventional T cell biology.

immunology↗

bioRxiv2020

The retinoic acid receptor drives neuroinflammation and fine tunes the homeostasis of interleukin-17-producing T cells

The vitamin A metabolite retinoic acid (RA) is critical for the maturation and function of the immune system, however, our knowledge regarding its role in gamma delta ({gamma}{delta}) T cells is limited. By specifically inactivating the RA receptor alpha (RAR) in type 3 lymphocytes and using a combination of fetal thymic organ cultures and single-cell RNA-sequencing we found that RA strengthened TCR signaling to limit the embryonic development of interleukin(IL)-17-producing {gamma}{delta} T cells ({gamma}{delta}T17), while at the same time it promoted their survival after birth. In adult mice, RA imposed a multi-level transcriptional program allowing {gamma}{delta}T17 cells to become activated, survive and sense interferon. Consequently, cells with inactive RAR responded poorly to immunization and produced low level of cytokines leading to near disease resistance in the experimental autoimmune encephalomyelitis model. Finally, RA was required for optimal expression of the 4{beta}1 integrin and {gamma}{delta}T17 cell infiltration to the brain. Collectively, these studies suggest that by acting at various stages during the lifetime of {gamma}{delta} T cells, RA supports their normal development, their survival and their ability to respond to inflammatory stimuli.

immunology↗

bioRxiv2020

Inhibitor of apoptosis proteins 1 and 2 are required for the homeostasis of murine RORγt+ γδ T cells

Environmental and molecular cues early in life are often associated with the permanent shaping of our immune system during adulthood. Although increasing, our knowledge of the signaling pathways that operate in early life and their temporal mode of action is limited. Herein, we demonstrate that the cellular inhibitor of apoptosis proteins 1 and 2 (cIAP1/2), which are E3 ubiquitin ligases and master regulators of the nuclear factor-kappa B (NF-{kappa}B) pathway, function during late neonatal and prepubescent life to sustain interleukin(IL)-17-producing gamma delta T cells ({gamma}{delta}T17) and group 3 innate lymphoid cells (ILC3). We show that cell-intrinsic deficiency in cIAP1/2 at 3-4 weeks of life leads to downregulation of the transcription factors cMAF and ROR{gamma}t, and failure to enter cytokine-induced cell cycle. This is followed by progressive loss of {gamma}{delta}T17 cells and ILC3 while mice are aging. Mice deficient in cIAP1/2 have severely reduced {gamma}{delta}T17 cells and ILC3, present with suboptimal {gamma}{delta}T17 responses in the skin, lack small intestinal isolated lymphoid follicles and cannot control intestinal bacterial infection. Mechanistically, these effects appear to be dependent on overt activation of the non-canonical NF-{kappa}B pathway. Our data identify the cIAP E3 ubiquitin ligases as critical early life molecular switches for establishing effective type-3 immunity during aging.

immunology↗

bioRxiv2019

Migration of intestinal dendritic cell subsets upon intrinsic and extrinsic TLR3 stimulation

Initiation of adaptive immunity to particulate antigens in lymph nodes largely depends on their presentation by migratory dendritic cells (DCs). DC subsets differ in their capacity to induce specific types of immunity, allowing subset-specific DC-targeting to influence vaccination and therapy outcomes. Faithful drug design however requires exact understanding of subset-specific versus global activation mechanisms. cDC1, the subset of DCs that excel in supporting immunity towards viruses, intracellular bacteria and tumors, express uniquely high levels of the pattern recognition receptor TLR3. Using various genetic models, we show here that both the cDC1 and cDC2 subsets of cDCs are activated and migrate equally well in response to TLR3 stimulation in a cell extrinsic and TNF dependent manner, but that cDC1 show a unique requirement for type I interferon signaling. Our findings reveal common and differing pathways regulating DC subset migration, offering important insights for the design of DC-based vaccination and therapy approaches.

immunology↗

bioRxiv2019

The neonatal microenvironment programs conventional and intestinal Tbet+ γδT17 cells through the transcription factor STAT5

Interleukin(IL)-17-producing ROR{gamma}t+ {gamma}{delta} T ({gamma}{delta}T17) cells develop in the embryonic thymus and participate in type 3 immune responses. Herein we show that {gamma}{delta}T17 cells rapidly proliferate within neonatal lymph nodes and gut, where upon entry they uniquely upregulate Tbet and co-express IL-17, IL-22 and interferon(IFN) {gamma} in a STAT3 and retinoic acid dependent manner. Neonatal expansion was halted in mice conditionally deficient in STAT5 and its loss resulted in {gamma}{delta}T17 cell depletion from all adult organs. Hyperactive STAT5 mutant mice showed that the STAT5A homologue had a dominant role over STAT5B in promoting {gamma}{delta}T17 cell expansion and downregulating gut-associated Tbet. In contrast, STAT5B preferentially expanded IFN{gamma}-producing {gamma}{delta} populations. Importantly, mice lacking {gamma}{delta}T17 cells due to STAT5 deficiency displayed a profound resistance to experimental autoimmune encephalomyelitis. Our data identify for the first time STAT5 as a key molecular checkpoint allowing {gamma}{delta}T17 cells to pass through a critical neonatal developmental window to acquire tissue-specific characteristics essential for infection and autoimmunity.

immunology↗