Project description:Aortic aneurysms is increasing as the human population ages. Pathological oxidative stress is implicated in development of aortic aneurysms. We pursued a chemogenetic approach to create an animal model of aortic aneurysm formation using a transgenic mouse line DAAO-TGTie2 that expresses yeast D-amino acid oxidase (DAAO) under control of the endothelial Tie2 promoter. In DAAO-TGTie2 mice, DAAO generates the reactive oxygen species hydrogen peroxide (H2O2) in endothelial cells only when provided with D-amino acids. When DAAO-TGTie2 mice are chronically fed D-alanine, the animals become hypertensive and develop abdominal but not thoracic aortic aneurysms. Generation of H2O2 in the endothelium leads to oxidative stress throughout the vascular wall. Proteomic analyses indicate that the oxidant-modulated protein kinase JNK1 is dephosphorylated by the phophoprotein phosphatase DUSP3 in abdominal but not thoracic aorta, causing activation of KLF4-dependent transcriptional pathways that trigger phenotypic switching and aneurysm formation. Pharmacological DUSP3 inhibition completely blocks aneurysm formation caused by chemogenetic oxidative stress. These studies establish that regional differences in oxidant-modulated signaling pathways lead to differential disease progression in discrete vascular beds, and identify DUSP3 as a potential pharmacological target for the treatment of aortic aneurysms.
Project description:Plasma biomarkers that identify abdominal aortic aneurysm (AAA) rupture risk would greatly assist in stratifying patients with small aneurysms. Identification of such biomarkers has hitherto been unsuccessful over a range of studies using different methods. The present study used an alternative proteomic approach to find new, potential plasma AAA biomarker candidates. Pre-fractionated plasma samples from twelve patients with AAA and eight matched controls without aneurysm were analyzed by mass spectrometry applying a tandem mass tag (TMT) technique. Eight proteins were differentially regulated in patients compared to controls, including decreased levels of the enzyme bleomycin hydrolase. The down-regulation of this enzyme was confirmed in an extended validation study using an ELISA assay. The TMT-based proteomic approach thus identified novel potential plasma biomarkers for AAA.
Project description:Analysis of differential gene expression for rutured vs stable abdominal aortic aneurysms (AAA) and for intermediate size (≤55mm) vs large (>70mm) AAA.
Project description:Thoracic aortic aneurysms have a higher prevalence in male patients compared to female patients. Marfan syndrome causes a hereditary form of TAA with dilation of the aortic root. Male patients with Marfan syndrome are more likely than women to have aortic dilation and dissection and mouse models of Marfan syndrome demonstrate larger aortic roots in males compared to females even after adjustment for body size. Similar sex disparities are present in patients and models of abdominal aortic aneurysms where estrogen has been demonstrated to attenuate aneurysm formation perhaps through anti-inflammatory mechanisms. In this study we demonstrate the effects of estrogen on aortic dilation and rupture in a Marfan mouse model and we investigate if these effects operate through suppression of complement components of the immune system.
Project description:The development of aneurysm is involved in imbalance between connective tissue repair and degradation. CD34+ cells are a heterogeneous population with stem/progenitor cell properties. However, the role of CD34+ cells in abdominal aortic aneurysms/dissections (AAAs) is unknown. We aimed to uncover the exact role and potential mechanism of CD34+ cells in the development of AAAs.
Project description:Global gene expression information that can be used to identify pathways involved in the pathophysiology of disease. We used microarrays to identify which genes are expressed in either the abdominal aorta (control) or in abdominal aortic aneurysms (case), and also which genes may be differential between the two tissue states. Keywords: Characterization of expression in both diseased and non-diseased abdominal aortas.
Project description:We conducted single-cell RNA sequencing (scRNA-seq) on CD4+ T cells of the aneurysmal aorta and the corresponding splenic cells, in order to unveil the diversity of CD4+ T Cell in Abdominal Aortic Aneurysms.
Project description:This study aims at identifying genes involved in this metabolic activation potentially related to rupture. A genome-wide transcriptomic analysis was performed on biopsies collected from patients with a Fluorodeoxyglucose (FDG) uptake both in the positive spot (A+Pos) and in a distant negative site of the same aneurysm (A+Neg). These paired biopsies were further compared to samples collected from (abdominal aortic aneurysms) AAA patients with no FDG uptake (A0) in order to discriminate biological alterations associated with FDG uptake, to detect new systemic biomarkers correlated with a higher risk of rupture and to identify new pathways involved in the progression and rupture of AAA).