Biology subjects

McGovern, J.

Publications and source records attributed to McGovern, J..

9 recordsLinked to original sources

bioRxiv2026

Loss of Sun2 ablates nuclear mechanosensing-driven extracellular matrix production and mitigates lung fibrosis

Fibrosis and pathological stiffening of tissue are driven by mechanical and biochemical signaling pathways. Here, we find that Sun2, an integral inner nuclear membrane component of Linker of Nucleoskeleton and Cytoskeleton (LINC) complexes, is up-regulated in the lung of patients suffering from fibrotic conditions and in fibroblasts during an injury-induced mouse model of lung fibrosis. Sun2 protein levels also increase in primary lung fibroblasts in a substrate stiffness-dependent manner. Sun2-/- primary lung fibroblasts respond to TGF{beta}, become contractile, and express a key marker of extracellular matrix-producing fibroblasts, Cthrc1. Consistent with this, Sun2 is dispensable for myofibroblast formation and repairing the alveolar barrier after bleomycin injury. Remarkably, however, fibrosis does not develop in bleomycin-treated Sun2-/- mouse lungs. This is explained by the requirement for Sun2 to up-regulate genes encoding extracellular matrix proteins. We therefore suggest that Sun2-containing LINC complexes contribute to a mechanical coincidence detection mechanism that acts in concert with canonical TGF{beta} signaling necessary for pathologic extracellular matrix protein production, representing a nuclear mechanosensing node for intervention in fibrotic diseases of the lung.

cell biology↗

bioRxiv2024

ENTPD3-specific CAR Regulatory T cells for Local Immune Control in T1D

Despite advances in Type 1 Diabetes (T1D) management such as hybrid closed loop systems, patients still face significant morbidity, reduced life expectancy, and impaired glucose regulation compared to healthy individuals or those with pancreas transplants. Here we developed beta cell-specific Chimeric Antigen Receptors (CAR) targeting the antigen ectonucleoside triphosphate diphosphohydrolase 3 (ENTPD3) using a novel cell-based phage display methodology. ENTPD3 is highly expressed on beta cells of both early and progressed T1D patients. ENTPD3 CAR regulatory T cells (Tregs) homed, expanded and persisted in pancreatic islets in a T1D mouse model (NOD) and completely prevented disease progression. Human ENTPD3 CAR Tregs displayed a stable regulatory phenotype, strong activation, and suppression. Importantly, ENTPD3 CAR T cells recognised and were fully activated by human islets. This approach holds great promise as a durable treatment option for patients with prediabetes, new-onset diabetes, or those undergoing beta cell replacement therapy.

immunology↗

bioRxiv2024

A Nerve-Fibroblast Axis in Mammalian Lung Fibrosis

Fibrosis contributes to incurable pathologies in vital organs including the lung. Myofibroblasts are fibrogenic effector cells that accumulate via incompletely understood mechanisms. We discovered that 1-adrenoreceptor expressing myofibroblasts receive sympathetic nerve-derived noradrenergic inputs in fibrotic mouse and human lungs. We combined optical clearing, whole lung imaging, cell-specific gene deletion in sympathetic nerves and myofibroblasts, pharmacologic interventions, sympathetic nerve co-culture and precision-cut lung slices, with analysis of bronchoalveolar lavage fluid, lung tissues, single-cell RNA sequencing datasets, and isolated lung fibroblasts from patients with diverse forms of pulmonary fibrosis to characterize a fibrogenic unit comprised of aberrantly patterned sympathetic nerves and 1-adrenoreceptor subtype D expressing myofibroblasts. The discovery of this previously undefined nerve-fibroblast axis that is conserved across species demonstrates the pivotal contribution of nerves to tissue remodeling and heralds a novel paradigm in fibrosis research.

cell biology↗

bioRxiv2024

Damage sensing through TLR9 Promotes Viral Clearance and Recovery During Influenza Infection

Host response aimed at eliminating the infecting pathogen, as well as the pathogen itself, can cause tissue injury. Tissue injury leads to the release of a myriad of cellular components including mitochondrial DNA, which the host senses through pattern recognition receptors. How the sensing of tissue injury by the host shapes the anti-pathogen response remains poorly understood. In this study, we utilized mice that are deficient in toll-like receptor-9 (TLR9), which binds to unmethylated CpG DNA sequences such as those present in bacterial and mitochondrial DNA. To avoid direct pathogen sensing by TLR9, we utilized the influenza virus, which lacks ligands for TLR9, to determine how damage sensing by TLR9 contributes to anti-influenza immunity. Our data show that TLR9-mediated sensing of tissue damage promotes an inflammatory response during early infection, driven by the epithelial and myeloid cells. Along with the diminished inflammatory response, the absence of TLR9 led to impaired viral clearance manifested as a higher and prolonged influenza components in myeloid cells including monocytes and macrophages rendering them highly inflammatory. The persistent inflammation driven by infected myeloid cells led to persistent lung injury and impaired recovery in influenza-infected TLR9-/-mice. Further, we show elevated TLR9 activation in the plasma samples of patients with influenza and its association with the disease severity in hospitalized patients, demonstrating its clinical relevance. Overall, we demonstrate an essential role of damage sensing through TLR9 in promoting anti-influenza immunity and inflammatory response. Author SummaryTissue damage is an inevitable outcome of clinically relevant lung infections, but the host mechanisms for detecting such damage during infection are not well understood. We investigated the role of Toll-like receptor 9 (TLR9) in sensing tissue damage caused by influenza. Since influenza lacks TLR9 ligands, we hypothesized that TLR9 signaling is driven by tissue damage molecules like mitochondrial DNA (mtDNA). Our data indicate that TLR9 reduces early inflammatory lung injury but impairs viral clearance, resulting in extensive immune cell infection, persistent inflammation, and delayed recovery. Myeloid-specific TLR9 deletion ameliorated late-stage inflammatory responses. In humans, influenza-infected individuals exhibited elevated TLR9 activity and mtDNA levels in plasma compared to healthy controls, with higher TLR9 activation potential correlating with severe disease requiring ICU admission. These findings suggest that TLR9-mediated damage sensing triggers both inflammatory tissue injury and viral clearance. These data indicate that TLR9 activity can serve as a crucial biomarker and therapeutic target to limit influenza induced tissue injury.

immunology↗

bioRxiv2024

The Effect of Adrenalectomy on Bleomycin-Induced Pulmonary Fibrosis in Mice

Progressive lung fibrosis is often fatal and has limited treatment options. Though the mechanisms are poorly understood, fibrosis is increasingly linked with catecholamines such as adrenaline (AD) and noradrenaline (NA), and hormones such as aldosterone (ALD). The essential functions of adrenal glands include the production of catecholamines and numerous hormones, but the contribution of adrenal glands to lung fibrosis remains less well studied. Here, we characterized the impact of surgical adrenal ablation in the bleomycin model of lung fibrosis. Wild type mice underwent surgical adrenalectomy or sham surgery followed by bleomycin administration. We found that the bleomycin induced collagen over deposition in the lung was not affected by adrenalectomy. However, histologic indices of lung remodeling were ameliorated by adrenalectomy. These findings were accompanied by a decrease in bronchoalveolar lavage (BAL) cell count along with concomitant reductions in alpha smooth muscle actin (SMA) and fibronectin. Surgical adrenalectomy completely abrogated AD detection in all compartments, but only reduced NA in the BAL of uninjured mice. Systemic ALD levels were reduced after adrenalectomy. Taken together, these results support the presence of pulmonary-adrenal axis in lung fibrosis and suggest that adrenalectomy is protective in this disease. Further investigation will be needed to better understand this observation and aid in the development of novel therapeutic strategies.

pathology↗

bioRxiv2023

Aerosolized α1 adrenoreceptor antagonism does not affect experimentally induced lung fibrosis in animal models

Pulmonary Fibrosis is a progressive and incurable condition that complicates many disease states. Adrenergic hyperinnervation and accumulation of fibroblasts expressing 1- adrenoreceptors have been implicated in this process. Previous studies have demonstrated that systemic treatment with an 1-adrenoreceptors antagonist attenuates fibrotic endpoints in lung fibrosis models. In an attempt to develop a lung targeted therapy, we determined whether 1- adrenoreceptors antagonism delivered via inhaled administration of terazosin exerts antifibrotic benefits in experimentally induced lung fibrosis. C57/BL6 mice treated with bleomycin, or a doxycycline inducible line of transgenic mice with lung specific overexpression of the bioactive form of the human TGF{beta}1 (TGF{beta}1-Tg+ model), received nebulized terazosin at varying doses on a therapeutic schedule following the induction of fibrosis and were sacrificed at 21 days. Airway inflammation, fibrotic endpoints, and lung function were evaluated. 1-adrenoreceptors antagonism delivered via this method did not impact airway inflammation as indicated by bronchoalveolar lavage cell counts, and there was no significant difference observed in soluble collagen content. There was similarly no significant difference in respiratory mechanics with terazosin administration. These data show that inhaled delivery of the 1-adrenoreceptors antagonist terazosin by this method is ineffective at treating fibrosis in these models and suggest that alternative dosing schedules or delivery methods may be more fruitful avenues of investigation. Further exploration of these findings may provide new therapeutic options and illuminate mechanisms through which adrenergic innervation and 1-adrenoreceptors mediate fibrosis in the adult mammalian lung.

pathology↗

bioRxiv2021

NKG2D signaling regulates IL-17A-producing γδT cells to promote cancer progression

{gamma}{delta}T cells are unconventional T cells particularly abundant in mucosal tissues that play an important role in tissue surveillance and homeostasis. {gamma}{delta}T cell activation is mediated by the T cell receptor composed of {gamma} and {delta} chains, as well as activating receptors for stress-induced ligands, such as NKG2D. Contrary to the well-established anti-tumor function of {gamma}{delta}T cells, recent studies have shown that {gamma}{delta}T cells can promote tumor development in certain contexts. However, the mechanisms leading to this diseasepromoting role remain poorly understood. Here, we show that mice lacking {gamma}{delta}T cells survive longer in a mouse model of intestinal cancer, further supporting their pro-tumoral role. In a surprising conceptual twist, we found that these pro-tumor {gamma}{delta}T cells are regulated by NKG2D signaling, a receptor normally associated with cancer cell killing. Germline deletion of Klrk1, the gene encoding NKG2D, reduced the frequency of {gamma}{delta}T cells in the tumor microenvironment and delayed tumor progression. We further show that blocking NKG2D reduces the capability of {gamma}{delta}T cells to produce IL-17A in the pre-metastatic lung and that co-culture of lung T cells with NKG2D ligand-expressing tumor cells specifically increases the frequency of {gamma}{delta}T cells. Together, these data support the hypothesis that in a tumor microenvironment where NKG2D ligands are constitutively expressed, {gamma}{delta}T cells accumulate in an NKG2D-dependent manner and drive tumor progression by secreting pro-inflammatory cytokines, such as IL-17A.

immunology↗

bioRxiv2018

Three-dimensional experiments and individual based simulations show that cell proliferation drives melanoma nest formation in human skin tissue

BackgroundMelanoma can be diagnosed by identifying nests of cells on the skin surface. Understanding the processes that drive nest formation is important as these processes could be potential targets for new cancer drugs. Cell proliferation and cell migration are two potential mechanisms that could conceivably drive melanoma nest formation. However, it is unclear which one of these two putative mechanisms plays a dominant role in driving nest formation.\n\nResultsWe use a suite of three-dimensional (3D) experiments in human skin tissue and a parallel series of 3D individual-based simulations to explore whether cell migration or cell proliferation plays a dominant role in nest formation. In the experiments we measure nest formation in populations of irradiated (non-proliferative) and non-irradiated (proliferative) melanoma cells, cultured together with primary keratinocyte and fibroblast cells on a 3D experimental human skin model. Results show that nest size depends on initial cell number and is driven primarily by cell proliferation rather than cell migration.\n\nConclusionsWe find that nest size depends on initial cell number, and is driven primarily by cell proliferation rather than cell migration. All experimental results are consistent with simulation data from a 3D individual based model (IBM) of cell migration and cell proliferation.

cell biology↗

bioRxiv2017

Quantifying Rates Of Cell Migration And Cell Proliferation In Co-Culture Barrier Assays Reveals How Skin And Melanoma Cells Interact During Melanoma Spreading And Invasion

Malignant spreading involves the migration of cancer cells amongst other native cell types. For example, in vivo melanoma invasion involves individual melanoma cells migrating through native skin, which is composed of several distinct subpopulations of cells. Here, we aim to quantify how interactions between melanoma and fibroblast cells affect the collective spreading of a heterogeneous population of these cells in vitro. We perform a suite of circular barrier assays that includes: (i) monoculture assays with fibroblast cells; (ii) monoculture assays with SK-MEL-28 melanoma cells; and (iii) a series of co-culture assays initiated with three different ratios of SK-MEL-28 melanoma cells and fibroblast cells. Using immunostaining, detailed cell density histograms are constructed to illustrate how the two subpopulations of cells are spatially arranged within the spreading heterogeneous population. Calibrating the solution of a continuum partial differential equation to the experimental results from the monoculture assays allows us to estimate the cell diffusivity and the cell proliferation rate for the melanoma and the fibroblast cells, separately. Using the parameter estimates from the monoculture assays, we then make a prediction of the spatial spreading in the co-culture assays. Results show that the parameter estimates obtained from the monoculture assays lead to a reasonably accurate prediction of the spatial arrangement of the two subpopulations in the co-culture assays. Overall, the spatial pattern of spreading of the melanoma cells and the fibroblast cells is very similar in monoculture and co-culture conditions. Therefore, we find no clear evidence of any interactions other than cell-to-cell contact and crowding effects.

cancer biology↗