Biology subjects

Golec, D. P.

Publications and source records attributed to Golec, D. P..

7 recordsLinked to original sources

bioRxiv2026

An ITK - SLP-76 Y173 Axis Regulates TCR Signal Persistence and Thymic Development

The TCR-induced tyrosine kinase cascade results in ITK-mediated phosphorylation of at least two substrates: PLC-{gamma}1 Y783, an essential mediator of TCR signaling, and SLP-76 Y173. We previously provided evidence that SLP-76 Y173 supports proximal TCR and Fc{varepsilon}RI signaling; but its role in thymocyte development was never explored. Here we demonstrate that SLP-76 Y173 was required for TCR/CD28-induced degradation of I{kappa}B; moreover, both ITK and SLP-76 Y173 were required for persistent TCR-induced phosphorylation of PLC-{gamma}1, ERK and p38. To explore whether SLP-76 Y173 may mediate ITK-dependent events in vivo, we replaced SLP 76 Y173 with phenylalanine in a mouse model. Like ITK-deficient thymocytes, SLP-76 Y173F thymocytes exhibited reduced thymic cellularity, reduced CD4/CD8 ratios, and reduced surface expression of CD5. In ex vivo-stimulated thymocytes, mutation of SLP-76 Y173 or inhibition of ITK reduced the persistence of TCR-induced calcium flux; moreover, TCR-induced phosphorylation of ERK and p38 depended on SLP-76 Y173. Like ITK-deficient thymi, SLP-76 Y173F thymocytes exhibited decreased production of CD4- iNKT1 thymocytes, coupled with increased production of innate-like CD4+ and CD8+ SP thymocytes. Our results provide strong evidence that the ITK substrate site, SLP-76 Y173, promotes TCR signal persistence that is required to mediate the thymic developmental effects of ITK.

immunology↗

bioRxiv2025

PI3Kdelta promotes T cell effector differentiation and plasticity during chronic infection

Persistent antigen exposure in chronic infections and cancer leads to a progressive state of T cell dysfunction known as exhaustion, which represents a major barrier to effective immune control, but allows antigen-specific T cells to persist. Understanding signaling pathways that mitigate exhaustion and reinvigorate CD8+ T cell effector function is a key goal for immunotherapeutic strategies. Here, we show that an activating mutant of phosphoinositide-3-kinase {delta} (PI3K{delta}) led to a reduction of FoxO1-dependent TCF-1+ stem-like progenitor CD8+ T cells that are required for sustaining antigen-specific T cells in response to chronic viral infection. Nonetheless, mice expressing activated PI3K{delta} maintained CD8+ T cell responses that were skewed instead towards effector-like cells in a FoxO1-independent manner, associated with an amplified IL-21-STAT3 response axis and improved viral control. Activated PI3K{delta} limited TOX expression, prevented epigenetic changes associated with T cell exhaustion, and promoted effector differentiation and function from both progenitor stem-like cells and cells with an exhausted phenotype. Together, this work uncovers a key role for PI3K{delta} activation in shaping the balance and plasticity between effector function and exhaustion while promoting T cell persistence during chronic infection, providing insight for immunotherapeutic strategies.

immunology↗

bioRxiv2025

Spatial organization of pulmonary type 2 inflammation by a macrophage-derived cholesterol metabolite

Effective pulmonary immunity requires the precise spatial organization of immune cells, yet the mechanisms guiding their intratissue positioning during inflammation remain unclear. Here, we identify a cholesterol-derived chemotactic axis that spatially organizes T helper 2 (TH2) cells during fungal-induced pulmonary type 2 inflammation. Inflammation-expanded macrophages expressing cholesterol-25-hydroxylase (CH25H) produce 25-hydroxycholesterol, which is converted into the oxysterol 7,25-dihydroxycholesterol to attract GPR183-expressing TH2 cells into infectious lesions. This TH2 positioning suppresses interferon-{gamma} responsiveness in inflammatory Ly6C macrophages, promoting fungal persistence. Disruption of this axis via TH2-specific GPR183 deletion restores type 1 macrophage activation and enhances fungal clearance. Our findings reveal a macrophage-driven, metabolite-based mechanism of immunosuppressive cell positioning in inflamed lung tissue.

immunology↗

bioRxiv2025

Sulfide is a keystone metabolite for gut homeostasis and immunity

Hydrogen sulfide is a gaseous, reactive molecule specifically enriched in the gastrointestinal tract. Here, we uncover a non-redundant role for sulfide in the control of both microbial and immune homeostasis of the gut. Notably, depletion of sulfide via both pharmaceutical and dietary interventions led to a profound collapse of CD4 T cells in the ileum of the small intestine lamina propria and significant impact on microbial ecology. As a result, mice with reduced sulfide within the gut were deficient in their ability to mount T cell dependent antibody responses to oral vaccine. Mechanistically, our results support the idea that sulfide could act directly on CD4 T cells via enhanced AP-1 activation, leading to heightened proliferation and cytokine production. This study uncovers sulfides as keystone components in gut ecology and provides mechanistic insight between diet, gut sulfide production and mucosal immunity.

immunology↗

bioRxiv2024

RasGRP1 Signalling Programs Developing γδ-Thymocytes towards the γδT17 Lineage Through Control of c-Maf Expression

The {gamma}{delta} TCR instructively directs both lineage specification and effector programming of developing {gamma}{delta} T cells. However, the manner in which different TCR signal strengths and other auxiliary signals coordinate downstream of the {gamma}{delta} TCR to regulate {gamma}{delta} T cell development remains unclear. In this study we characterized the role of Ras guanyl-releasing protein 1 (RasGRP1) in the development and effector programming of {gamma}{delta} T cells. While RasGRP1 was not necessary for bulk {gamma}{delta} T cell generation, we found it required for efficient generation of V{gamma}4+ thymocytes, and lineage-committed CD73+ {gamma}{delta} T cells in the thymus and periphery. Despite a decrease in immature CD73+ {gamma}{delta} thymocytes, we report an expansion of the perinatal wave of CD8+IFN{gamma}+ {gamma}{delta} T cell population in the absence of RasGRP1. IL-17 producing {gamma}{delta} T cells were significantly reduced in RasGRP1 KO mice, with a specific loss of V{gamma}2+ {gamma}{delta} T cells that corresponds to a loss of c-Maf expression as early as the DN1d thymocyte stage. Critically, these adult-programmed {gamma}{delta}T17s could express c-Maf in response to CCR9 stimulation, with RasGRP1 being required for CCR9-induced c-Maf expression. Thus, RasGRP1 activation serves as an important signalling hub in the effector programming of {gamma}{delta} T cells, which integrates signals from both non-TCR and TCR inputs to direct differentiation.

immunology↗

bioRxiv2024

A PI3Kδ-Foxo1-FasL signaling amplification loop rewires CD4+ T helper cell signaling, differentiation and epigenetic remodeling

While inputs regulating CD4+ T helper cell (Th) differentiation are well-defined, the integration of downstream signaling with transcriptional and epigenetic programs that define Th-lineage identity remain unresolved. PI3K signaling is a critical regulator of T cell function; activating mutations affecting PI3K{delta} result in an immunodeficiency with multiple T cell defects. Using mice expressing activated-PI3K{delta}, we found aberrant expression of proinflammatory Th1-signature genes under Th2-inducing conditions, both in vivo and in vitro. This dysregulation was driven by a robust PI3K{delta}-IL-2-Foxo1 signaling loop, fueling Foxo1-inactivation, loss of Th2-lineage restriction, altered chromatin accessibility and global impairment of CTCF-DNA interactions. Surprisingly, ablation of Fasl, a Foxo1-repressed gene, restored normal Th2 differentiation, TCR signaling and CTCF expression. BioID revealed Fas interactions with TCR- signaling components, which were supported by Fas-mediated potentiation of TCR signaling. Our results highlight Fas-FasL signaling as a critical intermediate in phenotypes driven by activated-PI3K{delta}, thereby linking two key pathways of immune dysregulation.

immunology↗

bioRxiv2021

γδ-Thymocyte Maturation and Emigration

The thymus is the site of both {beta} and {gamma}{delta}-T cell development. After several unique waves of {gamma}{delta}-T cells are generated in, and exported from, the fetal/neonatal thymus, the adult thymus continues to produce a stream of {gamma}{delta}-T cells throughout life. One intriguing feature of {gamma}{delta} T cell development is the coordination of differentiation and acquisition of effector function within the fetal thymus, however, it is less clear whether this paradigm holds true in adult animals. To investigate the relationship between maturation and time since V(D)J recombination in adult-derived {gamma}{delta}-thymocytes, we used the Rag2pGFP model. Immature (CD24+) {gamma}{delta}-thymocytes expressed high levels of GFP while only a small minority of mature (CD24-) {gamma}{delta}-thymocytes were GFP+. Similarly, most GFP+ {gamma}{delta}-splenocytes were immature, while some were mature. Analysis of {gamma}{delta}-recent thymic emigrants (RTEs) indicated that most {gamma}{delta}-T cell RTEs were CD24+ and GFP+ and adoptive transfer experiments showed that immature {gamma}{delta}-thymocytes could be maintained in the periphery for at least 3 days over which time they matured. With respect to the mature {gamma}{delta}-thymocytes that were GFP-, parabiosis experiments demonstrated that mature {gamma}{delta}-T cells did not recirculate from the periphery. Instead, a population of mature {gamma}{delta}-thymocytes remained resident in the thymus for at least 60 days while mature {gamma}{delta}-thymocytes derived solely from adult hematopoiesis were mostly lost from the thymus within 60 days. Collectively, these data demonstrate two streams of actively developing {gamma}{delta}-T cells in adult mice: an immature subset that quickly leaves the thymus and matures in the periphery, and one that completes maturation within the thymus over a longer period of time. Furthermore, there is a fetal-derived and heterogeneous population of resident {gamma}{delta}-thymocytes of unknown functional importance.

immunology↗