Project description:Concerning the roles of LCN2 in chronic inflammation and fibrosis, we investigated chronic liver inflammation and fibrosis using repeated carbon tetrachloride (CCl4) in mineral oil injection. We found that mice treated with the mineral oil vehicle alone also showed liver inflammation and more severe in wild-type mice compared to lipocalin 2 null mice.
Project description:Members of the lipocalin protein family serve as biomarkers for kidney disease and acute phase inflammatory reactions, and are under pre-clinical development for the diagnosis and therapy of allergies. However, none of the lipocalin family members has made the step into clinical development, mostly due to their complex biological activity and the lack of in-depth mechanistic knowledge. Here, we show that the hepatokine lipocalin 13 (LCN13) triggers glucose-dependent insulin secretion and cell proliferation of primary mouse islets. However, inhibition of endogenous LCN13 expression in lean mice did not alter glucose and lipid homeostasis. Enhanced hepatic secretion of LCN13 in either diet-induced or genetic obesity led to no discernable impact on systemic energy homeostasis, neither in preventive nor therapeutic setting. Of note, loss or forced LCN13 hepatic secretion did not trigger any compensatory regulation of related lipocalin family members. Together, these data are in stark contrast to the suggested gluco-regulatory and therapeutic role of LCN13 in obesity, and imply complex regulatory steps in LCN13 biology at the organismic level mitigating its principal insulinotropic effects.
Project description:IGF1R (Insulin-like Growth Factor 1 Receptor) is a ubiquitously expressed transmembrane tyrosine kinase receptor with multiple functions including inflammation. IGF activity maintains human lung homeostasis, being involved in relevant pulmonary diseases with an inflammatory component, such as lung cancer, COPD, asthma and pulmonary fibrosis. Here we examined the role of IGF1R in lung inflammation using mice with a postnatal deficiency of Igf1r and a model of bleomycin(BLM)-induced lung injury. Lung transcriptome analysis of Igf1r-deficient mice showed a general inhibition of transcription of genes related to epigenetics, inflammation/immune response and oxidative stress activity with potential pulmonary protective roles. Early upon intratracheal BLM treatment, mutant mice showed improved survival and milder pulmonary injury and inflammation. Their lungs presented down-regulation of macrophage (Marco/Adgre1), neutrophil-related (Cxcl1/Ly6g), pro-inflammatory (Tnf/Il1b/Il6), endothelial adhesion (Icam1/Pecam1) and alveolar damage (Aqp5/Sftpc) markers and up-regulation of resolution phase markers (Csf1/Il13/Cd209a). Changes in mRNA of IGF system genes were also found, in parallel to a hindered response to hypoxia (Hif1a) and increased expression of the anti-oxidative stress marker Gpx8. These findings identify Igf1r as an important player in oxidative stress and inflammation and suggest that targeting Igf1r may block the inflammatory response in lung diseases with this component.
Project description:Levels of asymmetric dimethylarginine (ADMA), an endogenous inhibitor of nitric oxide synthase, are increased in lung, sputum, exhaled breath condensate and plasma samples from asthma patients. ADMA is metabolized primarily by dimethylarginine dimethylaminohydrolase 1 (DDAH1) and DDAH2. We determined the effect of DDAH1 overexpression on development of allergic inflammation in mouse models of asthma. Wild type and DDAH1-transgenic mice were challenged with PBS or house dust mite (HDM). Airway inflammation was assessed by bronchoalveolar lavage (BAL) total and differential cell counts. Gene expression in lungs was determined by RNA-Seq and RT-quantitative PCR (qPCR). The expression of DDAH1 and DDAH2 was decreased in the lungs of mice following HDM exposure. Transgenic overexpression of DDAH1 resulted in decreased BAL total cell and eosinophil numbers following HDM exposure. Total IgE levels in serum and BAL fluid were decreased in HDM-exposed DDAH1-transgenic mice compared to HDM-exposed wild type mice. RNA-Seq results showed downregulation of genes in inducible nitric oxide synthase (iNOS) signaling pathway in PBS-treated DDAH1 transgenic mice versus PBS-treated wild type mice and downregulation of genes in IL-13/FOXA2 signaling pathway in HDM-treated DDAH1 transgenic mice versus HDM-treated wild type mice. Our findings suggest that decreased expression of DDAH1 in airway epithelial cells may contribute to allergic asthma and overexpression of DDAH1 attenuates allergen-induced airway inflammation through modulation of Th2 responses. mRNA profiles of WT and DDAH1-transgenic mice treated with PBS or house dust mite (HDM).