Biology subjects

Gentek, R.

Publications and source records attributed to Gentek, R..

8 recordsLinked to original sources

bioRxiv2025

FAK inhibitor treatment systemically regulates the glioblastoma immune environment via blocking monocyte trafficking

Glioblastoma (GBM) is the most common primary malignant brain tumour in adults with dismal survival rates, and current therapies, including most immunotherapies, are not efficacious due to the highly immunosuppressive microenvironment. Studies in other solid cancers report that impairment of the integrin effector pathway involving focal adhesion kinase (FAK) can promote anti-tumour immune responses. Therefore, we set out to address whether, and if so how, suppressing FAK function may influence GBM by using both tumour cell-specific FAK gene deletion and systemic delivery of a clinically relevant FAK kinase inhibitor (FAKi) VS-4718 in an orthotopic murine stem cell model of GBM. We found that treatment with the FAKi, but not tumour cell-specific FAK gene deletion, resulted in GBM clearance and improved survival. This was dependent on adaptive immunity, and tumour-infiltrating T cells in FAKi-treated tumours displayed increased cytotoxic potential and reduced exhaustion. We also found a significant reduction in immuno-suppressive peripherally-derived macrophages and FAKi treatment caused sequestration of inflammatory monocytes within the bone marrow, resulting in impaired monocyte trafficking to tumours as judged by adoptive transfer. This is due to suppression of key adhesion and migration signalling through 4{beta}1 integrin and CX3CR1 in peripheral monocytes. Our work here describes a previously unidentified role for FAK in trafficking of peripheral suppressive macrophages to GBM tumours, reducing T cell exhaustion and promoting anti-tumour immunity. This highlights a new way in which systemic FAK inhibitors can be used to provide a beneficial immune modulatory strategy for the treatment of GBM.

immunology↗

bioRxiv2025

The synovial lining macrophage layer develops in the first weeks of life in a CSF1- and TGFβ- dependent but monocyte-independent process.

Synovial joints harbor a protective lining layer, consisting of fibroblasts and macrophages, which form an epithelial-like barrier. In inflamed joints, lining macrophages regulate both early inflammatory cell influx and resolution. Despite these critical functions, it is currently unknown at what stage during development the synovial macrophage lining is established, and which signals drive this process. Here, we use a combination of genetic models and in vivo perturbations, single cell transcriptomics and imaging to delineate the process of lining formation in mice. We find that the synovial lining is immature at birth and becomes established within the first 3 weeks of life. In this window, the lining is gradually populated with macrophages that originate from fetal sources, proliferate and acquire the lining-specific transcriptional identity. In contrast, monocytes contribute only minimally to the developing lining, and their input remains limited in healthy adulthood. We identify CSF1 and TGF{beta} as key signals in this process, which also involves mechanosensing through PIEZO1. Our study thus identifies the early postnatal window as a critical period for lining macrophage development, with potential lifelong impact on joint health and disease.

immunology↗

bioRxiv2025

Perivascular RELM-positive synovial macrophages recruit monocytes at the onset of inflammatory arthritis

Macrophages, monocytes and neutrophils are major types of myeloid cells involved in inflammatory diseases, such as rheumatoid arthritis (RA). Recent scRNA-seq studies identified a remarkable diversity of synovial macrophages but, with the exception of lining macrophages, their geographical location and specific roles remain largely unexplored. Here, we localised the RELM-positive macrophages, predicted to produce high levels of monocyte-recruiting chemokines, to the synovial interstitium and more specifically, to the vicinity of interstitial blood vessels. Using complementary reporter mouse models, CCL2mCherry to label CCL2-producing cells, and CCR2CRE/mKate2 marking CCR2 expressing monocytes, we demonstrated that RELM-positive perivascular macrophages secrete CCL2 to recruit monocytes predominantly to the synovial interstitium at the onset of antigen-induced arthritis. The inflamed synovial environment guides the differentiation of the recruited monocytes into tissue-resident macrophages, including but not limited to macrophages expressing VSIG4, a characteristic marker of lining macrophages. Thus, RELM-positive macrophages orchestrate monocyte recruitment to the synovium during articular inflammation, contributing to a local replenishment of synovial lining macrophages.

immunology↗

bioRxiv2024

Mast cells are not essential for pubertal mammary gland branching.

Mast cells are long-lived, tissue-resident immune cells of the myeloid lineage with cardinal functions in allergy and atopic disease. They are now increasingly recognized also for protective roles e.g. against infections and venoms. Other functions originally assigned to mast cells in development and physiology, however, have been refuted, and for yet others, their true contribution remains uncertain. Mast cells have been implicated in promoting ductal branching in the pubertal mammary gland, the organ that produces and secretes milk in mammals, but these findings are based on mouse models that are not mast cell-specific. In this study, we therefore re-addressed the impact of mast cells on mammary gland branching using several complementary genetic models, including a new transgenic line. We report that neither constitutive deficiency of mast cells, nor their conditional ablation induced at puberty affected mammary gland branching. Our results thus dispute that mast cells promote this process in mice, at least in a unique and non-redundant manner. This study adds to a growing body of work clarifying the biological roles of mast cells, and further expands the toolbox available to the field of mast cell research.

developmental biology↗

bioRxiv2023

Bcl2 supports survival and metabolic fitness of quiescent tissue-resident ILC3

Group 3 innate lymphoid cells (ILC3) are potent effector cells with critical roles in enforcing immunity, barrier integrity and tissue homeostasis along the gastrointestinal tract. ILC3 are considered to be primarily tissue-resident cells, seeding the gastrointestinal tract during embryonic stages. However, the mechanisms through which ILC3 are maintained within these tissues are poorly understood. Here, we report that ILC3 are minimally replenished from bone marrow precursors in healthy adult mice, persist in the tissue for extended periods of time in the gut, and display a quiescent phenotype. Strikingly, despite robustly producing cytokines, LTi-like ILC3 remain non-proliferative during enteric bacterial infection. Survival of LTi-like ILC3 was found to be dependent upon the balance of the metabolic activity required to drive effector function and anti-apoptotic programs. Notably, the pro-survival protein Bcl-2 was required for the survival of LTi-like ILC3 but was rendered partially dispensable if mitochondrial respiration was inhibited. Together we demonstrate LTi-like ILC3 are a quiescent-like population that persists independently of haematopoietic replenishment to survive within the tissue microenvironment.

immunology↗

bioRxiv2022

CSF1R-dependent macrophages in the salivary gland are essential for epithelial regeneration following radiation-induced injury

The salivary glands often become damaged in individuals receiving radiotherapy for head and neck cancer, resulting in xerostomia, or chronic dry mouth. This leads to detrimental effects on their health and quality of life, for which there is no regenerative therapy. Macrophages are the predominant cell type in the salivary glands and are attractive therapeutic targets due to their unrivalled capacity to drive tissue repair and regeneration. Yet, the nature and role of macrophages in salivary gland homeostasis and whether or not they contribute to tissue repair/regeneration following injury is not well understood. Here, we have used single cell RNA-seq, multi-parameter flow cytometry and fluorescence microscopy to map the heterogeneity of the salivary gland macrophage compartment throughout development and following radiation-induced injury. We show that there are highly dynamic changes in the composition of the salivary gland macrophage compartment with age, in part due to changes in the ontogeny of these cells, determined using a suite of complementary fate mapping systems. A combination of mutant mice and antibody blockade demonstrates that salivary gland macrophages are dependent on CSF1, but not IL-34 or GM-CSF, for their development and maintenance. Finally, using an in vivo model of radiation-induced salivary gland injury combined with a novel Mafb-specific depletion system, we demonstrate an essential role for macrophages. Without macrophages the clearance of cells with DNA damage, and effective tissue repair following such injury, is severely comprised. Our data, therefore, indicate a strong case for exploring the therapeutic potential of manipulating macrophages in order to promote tissue repair and thus minimise salivary gland dysfunction after radiotherapy.

immunology↗

bioRxiv2020

Functionally distinct resident macrophage subsets differentially shape responses to infection in the bladder

Resident macrophages are abundant in the bladder, playing key roles in immunity to uropathogens. Yet, whether they are heterogeneous, where they come from, and how they respond to infection remain largely unknown. We identified two macrophage subsets in mouse bladders, MacM in the muscle and MacL in the lamina propria, with distinct protein expression and transcriptomes. Using a urinary tract infection model, we validated our transcriptomic analyses, finding that MacM macrophages phagocytosed more bacteria and polarized to a more anti-inflammatory profile, whereas the MacL subset died rapidly during infection. During resolution, monocyte-derived cells contributed to tissue-resident macrophage pools and both subsets acquired transcriptional profiles distinct from naive macrophages. Depletion of these altered macrophages resulted in the induction of a type 1 biased immune response to a second urinary tract infection, improving bacterial clearance. Our study uncovers the biology of resident macrophages and their response to an exceedingly common infection in a largely overlooked organ, the bladder.

immunology↗

bioRxiv2019

Origin and microenvironment contribute to the sexually dimorphic phenotype and function of peritoneal macrophages.

Macrophages reside in the body cavities where they maintain serosal homeostasis and provide immune surveillance. Peritoneal macrophages are implicated in the aetiology of pathologies including peritonitis, endometriosis and metastatic cancer thus understanding the factors that govern their behaviour is vital. Using a combination of fate mapping techniques, we have investigated the impact of sex and age on murine peritoneal macrophage differentiation, turnover and function. We demonstrate that the sexually dimorphic replenishment of peritoneal macrophages from the bone marrow, which is high in males and very low in females, is driven by changes in the local microenvironment that arise upon sexual maturation. Population and single cell RNAseq revealed striking dimorphisms in gene expression between male and female peritoneal macrophages that was in part explained by differences in composition of these populations. By estimating the time of residency of different subsets within the cavity and assessing development of dimorphisms with age and in monocytopenic Ccr2-/- mice, we demonstrate that key sex-dependent features of peritoneal macrophages are a function of the differential rate of replenishment from the bone marrow while others are reliant on local microenvironment signals. Importantly, we demonstrate that the dimorphic turnover of peritoneal macrophages contributes to differences in the ability to protect against pneumococcal peritonitis between the sexes. These data highlight the importance of considering both sex and age in susceptibility to inflammatory and infectious disease.

immunology↗