Project description:Toolsets available for in-depth analysis of scRNAseq datasets by biologists with little informatics experience is limited. Here we describe an informatics tool (PyMINEr) that fully automates cell type identification, cell type-specific pathway analyses, graph theory-based analysis of gene regulation, and detection of autocrine/paracrine signaling networks in silico. We applied PyMINEr to interrogate human pancreatic islet scRNAseq datasets and discovered several features of co-expression graphs including: concordance of scRNAseq-graph structure with both protein-protein interactions and 3D-genomic architecture; association of high connectivity and low expression genes with cell type-enrichment; and potential for graph-structure to clarify potential etiologies of enigmatic disease-associated variants. We further created a consensus co-expression network and autocrine/paracrine signaling networks within and across islet cell types from 7-datasets. PyMINEr correctly identified changes in BMP/WNT signaling associated with cystic fibrosis pancreatic acinar-cell loss. This proof-of-principle study demonstrates that the PyMINEr framework will be a valuable resource for scRNAseq analyses.
Project description:The role of paracrine/autocrine factors in inflammation, immune response and tumor development is well established. There is also an evidence that some of the cytokines there involved may participate in the regulation of the male gonads. However, their involvement in pathogenesis of male infertility has not been well defined yet. The aim of the present study was to examine the expression levels of IL-1 family members, IL-6, IL-10, TNF family, SCF and c-kit in infertile patients with idiopathic non-obstructive azoospermia (NOA) compared to men with normal spermatogenesis We analyzed testicular biopsy specimens obtained from 16 patients with non-obstructive azoospermia (NOA) and 4 with normal spermatogenesis using Affymetrix Human Gene 1.0 ST.
Project description:Nitric oxide (NO) produced by macrophages (MØs) is toxic to both host tissues and invading pathogens and its regulation is therefore essential to suppress host cytotoxicity. MØ arginase 1 (Arg1) inhibits NO production by competing with NO synthases for arginine, the common substrate of NO synthases and arginases. Two signal transduction pathways control Arg1 expression in MØs. First, a MyD88-dependent pathway induces Arg1 in intracellular infections, while a second Stat6-dependent pathway is required for Arg1 expression in alternativelyactivated MØs. We found that mycobacteria-infected MØs produce soluble factors that induce Arg1 in an autocrine-paracrine manner via Stat3. We identify these factors as IL-6, IL-10 and GCSF. We further establish that Arg1 expression is controlled by the MyD88-dependent production of IL-6, IL-10 and G-CSF rather than cell intrinsic MyD88 signaling to Arg1. Our data reveal the MyD88-dependent pathway of Arg1induction following BCG infection requires Stat3 activation and may result in the development of an immunosuppressive niche in granulomas due to the induced Arg1 production in surrounding uninfected MØs We used microarrays to perform genome wide expression analysis in mycobacteria-infected macrophages from C57Bl/6 WT and MyD88-knockout mice.
Project description:The role of paracrine/autocrine factors in inflammation, immune response and tumor development is well established. There is also an evidence that some of the cytokines there involved may participate in the regulation of the male gonads. However, their involvement in pathogenesis of male infertility has not been well defined yet. The aim of the present study was to examine the expression levels of IL-1 family members, IL-6, IL-10, TNF family, SCF and c-kit in infertile patients with idiopathic non-obstructive azoospermia (NOA) compared to men with normal spermatogenesis
Project description:Cutaneous squamous tumors rely on autocrine/paracrine loops for proper fitness. Targeting this Achilles’ heel is therefore considered a potential avenue for patient treatment. However, the mechanisms that engage and sustain such programs during tumor ontogeny are poorly understood. Here, we show that two Rho/Rac activators, the exchange factors Vav2 and Vav3, control the expression of an epithelial autocrine/paracrine program that regulates keratinocyte survival and proliferation as well as the creation of an inflammatory microenvironment. Vav proteins are also critically involved in some of the subsequent autocrine signaling loops activated in keratinocytes. The genetic inactivation of both Vav proteins reduces tumor multiplicity without hampering skin homeostasis, thus suggesting that pan-specific Vav therapies may be useful in skin tumor prevention and treatment. The dorsal skin of WT and DKO mice (Vav2-/-;Vav3-/-) were treated with either one or four applications of phorbol ester 12-O-tetradecanoylphorbol-13 acetate (TPA) (6.8 nmol in 200 μl acetone) two days after shaving. As control, we applied 200 μl of acetone. Animals were euthanized 24 hours after treatment.
Project description:Nitric oxide (NO) produced by macrophages (MØs) is toxic to both host tissues and invading pathogens and its regulation is therefore essential to suppress host cytotoxicity. MØ arginase 1 (Arg1) inhibits NO production by competing with NO synthases for arginine, the common substrate of NO synthases and arginases. Two signal transduction pathways control Arg1 expression in MØs. First, a MyD88-dependent pathway induces Arg1 in intracellular infections, while a second Stat6-dependent pathway is required for Arg1 expression in alternativelyactivated MØs. We found that mycobacteria-infected MØs produce soluble factors that induce Arg1 in an autocrine-paracrine manner via Stat3. We identify these factors as IL-6, IL-10 and GCSF. We further establish that Arg1 expression is controlled by the MyD88-dependent production of IL-6, IL-10 and G-CSF rather than cell intrinsic MyD88 signaling to Arg1. Our data reveal the MyD88-dependent pathway of Arg1induction following BCG infection requires Stat3 activation and may result in the development of an immunosuppressive niche in granulomas due to the induced Arg1 production in surrounding uninfected MØs
Project description:Cutaneous squamous tumors rely on autocrine/paracrine loops for proper fitness. Targeting this Achilles’ heel is therefore considered a potential avenue for patient treatment. However, the mechanisms that engage and sustain such programs during tumor ontogeny are poorly understood. Here, we show that two Rho/Rac activators, the exchange factors Vav2 and Vav3, control the expression of an epithelial autocrine/paracrine program that regulates keratinocyte survival and proliferation as well as the creation of an inflammatory microenvironment. Vav proteins are also critically involved in some of the subsequent autocrine signaling loops activated in keratinocytes. The genetic inactivation of both Vav proteins reduces tumor multiplicity without hampering skin homeostasis, thus suggesting that pan-specific Vav therapies may be useful in skin tumor prevention and treatment.
Project description:Neuregulin-1 (NRG1) is a paracrine growth factor, secreted by cardiac endothelial cells (Ecs) in conditions of cardiac overload/injury. The current concept is that the cardiac effects of NRG1 are mediated by activation of ERBB4/ERBB2 receptors on cardiomyocytes. However, recent studies have shown that paracrine effects of NRG1 on fibroblasts and macrophages are equally important. Here, we hypothesize that NRG1 autocrine signaling plays a role in cardiac remodeling. We generated EC–specific Erbb4 knockout mice to eliminate endothelial autocrine ERBB4 signaling without affecting paracrine NRG1/ERBB4 signaling in the heart. We first observed no basal cardiac phenotype in these mice up to 32 weeks. We next studied these mice following transverse aortic constriction (TAC), exposure to angiotensin II (Ang II) or myocardial infarction in terms of cardiac performance, myocardial hypertrophy, myocardial fibrosis and capillary density. In general, no major differences between EC–specific Erbb4 knockout mice and control littermates were observed. However, 8 weeks following TAC both myocardial hypertrophy and fibrosis were attenuated by EC–specific Erbb4 deletion, albeit these responses were normalized after 20 weeks. Similarly, 4 weeks after Ang II treatment myocardial fibrosis was less pronounced compared to control littermates. These observations were supported by RNA-sequencing experiments on cultured endothelial cells showing that NRG1 controls the expression of various hypertrophic and fibrotic pathways. Overall, this study shows a role of endothelial autocrine NRG1/ERBB4 signaling in the modulation of hypertrophic and fibrotic responses during early cardiac remodeling. This study contributes to understanding the spatio-temporal heterogeneity of myocardial autocrine and paracrine responses following cardiac injury.
Project description:Growth differentiating factor (GDF)15 is a TGFβ superfamily cytokine and a reported biomarker of heart failure. Myocardial expression of GDF15 is increased in heart failure. Yet, the mechanisms that control synthesis and release of GDF15 as well as the autocrine/paracrine functions of GDF15 on fibroblast function is lacking. Thus, the aim of this study was to investigate signaling pathways and functions of GDF15 in cardiac fibroblasts. Cardiac fibroblasts and cardiac myocytes were isolated from adult C57/BL6 mice, maintained in primary culture and stimulated with recombinant (r)GDF15 or recombinant (r)CCN2. Short-term stimulation (30 minutes) of cardiac fibroblasts demonstrated a GDF15-induced activation of several intracellular signaling pathways including a concentration-dependent increase of phospho-Smad3(Ser423/425) (p<0.05, n=3), phospho-AKT(Ser473) (p<0.05, n=3) and phospho-IκBα(Ser32/36) (p<0.05, n=3) levels. However, rGDF15 did not phosphorylate Smad3(Ser423/425) or IκBα(Ser32/36) in cardiac myocyte. Cardiac fibroblasts exposed to rGDF15 for 48 hours displayed differentiation towards myofibroblasts reflected by increased levels of the differentiation marker α-smooth muscle actin (SMA) similar to cardiac fibroblasts stimulated with TGFβ. The effect of GDF15 on α-SMA was dose-dependent ranging from 500 nM - 20 nM rGDF15 (p<0.05, n=3). Differentiation towards a myofibroblast phenotype in the presence of GDF15 was also supported by higher matrix metalloproteinase (MMP) enzyme activity in the cell culture medium (6±1 fold increase, n=3, p<0.05) and increased expression and release of MMP-3, 9 and 13. Immunoreactive GDF15 was predominantly found in cardiac myocytes. Recombinant CCN2 substantially induced GDF15 expression in cardiac myocytes, but not in cardiac fibroblasts. In conclusion, our data demonstrate that GDF15 is a paracrine factor in myocardial tissue and specifically regulated by CCN2 in cardiac myocytes. GDF15 has similar effects as TGFβ on fibroblasts by activation of intracellular signaling pathways and differentiation to a myofibroblasts phenotype.