Biology subjects

Jenkins, S. J.

Publications and source records attributed to Jenkins, S. J..

5 recordsLinked to original sources

bioRxiv2021

The transcription factor EGR2 is indispensable for tissue-specific imprinting of alveolar macrophages in health and tissue repair

Alveolar macrophages are the most abundant macrophages in the healthy lung where they play key roles in homeostasis and immune surveillance against air-borne pathogens. Tissue-specific differentiation and survival of alveolar macrophages relies on niche-derived factors, such as colony stimulating factor 2 (CSF-2) and transforming growth factor beta (TGF-{beta}). However, the nature of the downstream molecular pathways that regulate the identity and function of alveolar macrophages and their response to injury remains poorly understood. Here, we identify that the transcriptional factor EGR2 is an evolutionarily conserved feature of lung alveolar macrophages and show that cell-intrinsic EGR2 is indispensable for the tissue-specific identity of alveolar macrophages. Mechanistically, we show that EGR2 is driven by TGF-{beta} and CSF-2 in a PPAR-{gamma}-dependent manner to control alveolar macrophage differentiation. Functionally, EGR2 was dispensable for lipid handling, but crucial for the effective elimination of the respiratory pathogen Streptococcus pneumoniae. Finally, we show that EGR2 is required for repopulation of the alveolar niche following sterile, bleomycin-induced lung injury and demonstrate that EGR2-dependent, monocyte-derived alveolar macrophages are vital for effective tissue repair following injury. Collectively, we demonstrate that EGR2 is an indispensable component of the transcriptional network controlling the identity and function of alveolar macrophages in health and disease. One Sentence SummaryEGR2 controls alveolar macrophage function in health and disease

immunology↗

bioRxiv2021

Classical macrophage polarisation is limited by human β-defensin 3 via an autocrine IL-4 dependent process.

Human {beta}-defensin 3 (HBD3), is an anti-microbial host-defence peptide, that can rapidly enter macrophages to modulate TLR4 responses to lipopolysaccharide. However, the molecular mechanisms by which HBD3 exerts this anti-inflammatory influence remain unclear. Here, we show mice deleted for the orthologue of HBD3 have an increased acute lipopolysaccharide response in vivo. Furthermore, we found that HBD3 limited the response of macrophages to classical activation, and contemporaneously drove expression of IL-4. An increase in markers of alternative activation, and a change in metabolic flux was also observed. Consistent with these results, HBD3 enhanced the IL-4 mediated polarisation of naive macrophages. Finally, we demonstrate that the ability of HBD3 to limit macrophage classical activation requires IL-4R. These data reveal a previously unrecognised role for HBD3 in influencing the polarisation state of macrophages to enable a state conducive for repair and resolution. SYNOPSIS O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=131 SRC="FIGDIR/small/442606v2_ufig1.gif" ALT="Figure 1"> View larger version (25K): org.highwire.dtl.DTLVardef@f81c9aorg.highwire.dtl.DTLVardef@11dca23org.highwire.dtl.DTLVardef@c1e241org.highwire.dtl.DTLVardef@ed46ed_HPS_FORMAT_FIGEXP M_FIG C_FIG The anti-microbial host-defence peptide, Human {beta}-defensin 3 (HBD3), is shown here to modulate the inflammatory response to classical activation by promoting alternative activation through IL-4R, to enable a state conducive for repair and resolution. O_LIKnockout mice for the orthologous gene for HBD3, demonstrate increased acute lipopolysaccharide inflammatory response. C_LIO_LIHBD3 limited the classical activation of macrophages polarised with LPS/IFN{gamma} and drove expression of IL-4. Cells also displayed increase in alternative activation markers and promotion of oxidative phosphorylation. C_LIO_LIHBD3 enhanced the IL-4-mediated activation of naive macrophages. C_LIO_LIThe ability of HBD3 to limit macrophage classical activation and contemporaneously promote alternative activation required IL-4R. C_LI

immunology↗

bioRxiv2020

Recruited macrophages that colonise the post-inflammatory peritoneal niche convert into functionally divergent resident cells

Inflammation generally leads to substantial recruitment of monocyte-derived macrophages. What regulates the fate of these cells and to what extent they can assume the identity and function of resident macrophages remains unclear. We compared the normal fate of inflammation-elicited macrophages in the peritoneal cavity with their potential under non-inflamed conditions and in the absence of established resident macrophages. Following mild inflammation, elicited macrophages persisted for at least 5 months but failed to fully assume a GATA6hi resident identity due to the presence of enduring resident cells. In contrast, severe inflammation resulted in ablation of resident macrophages and a protracted phase wherein the cavity was incapable of sustaining a resident phenotype, yet ultimately elicited cells acquired a mature GATA6hi identity. Elicited macrophages also exhibited divergent features resulting from inflammation-driven alterations to the peritoneal cavity micro-environment and environment-independent features related to origin and time-of-residency. Critically, one environment-dependent feature of inflammation-elicited macrophages irrespective of severity of inflammation was a failure to produce the chemokine CXCL13, which correlated with a progressive loss in accumulation of peritoneal B1 cells post-inflammation. Hence, rather than being predetermined, the fate of inflammation-elicited peritoneal macrophages appears largely regulated by environment, changes in which result in long-term alteration in function of the peritoneal macrophage compartment post-inflammation.

immunology↗

bioRxiv2020

Macrophages can either inhibit or enhance endometriosis depending on their origin

Macrophages are intimately involved in the pathophysiology of endometriosis, a chronic inflammatory disorder characterized by the growth of endometrial-like tissue (lesions) outside the uterus. By combining genetic and pharmacological monocyte and macrophage depletion strategies we determined the ontogeny and function of macrophages in a mouse model of induced endometriosis. We demonstrate that lesion-resident macrophages are derived from eutopic endometrial tissue, infiltrating large peritoneal macrophages (LpM) and monocytes. Furthermore, we found endometriosis to trigger continuous recruitment of monocytes and expansion of CCR2+ LpM. Depletion of eutopic endometrial macrophages results in smaller endometriosis lesions, whereas constitutive inhibition of monocyte recruitment significantly reduces peritoneal macrophage populations and increased the number of lesions. We propose a putative model whereby endometrial macrophages are pro-endometriosis whilst newly-recruited monocyte-derived macrophages, possibly in LpM form, are anti-endometriosis. These observations highlight the importance of monocyte-derived macrophages in limiting disease progression.

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↗