Project description:Aortic smooth muscle cell (SMC) phenotype modulation is a central feature of cell-mediated pathology in Marfan syndrome aortic aneurysm and Klf4 is proposed to contribute to this process. We generated mice with smooth muscle cell-specific Klf4 deletion using an Myh11-creERT2 transgene, induced deletion at 8 weeks and performed single cell RNA sequencing at 24 weeks on whole aortic root tissues.
Project description:We report dynamic temporal and spatial smooth muscle cell phenotype modulation using aortic single cell RNA sequencing in a murine model of Marfan syndrome (Fbn1C1041G/+) and littermate controls. Aortic root/ascending aortic tissue samples from both genotypes were studied at 4 and 24 weeks of age. The non-aneurysmal descending thoracic aorta was also studied at 24 weeks. Finally human aortic tissue from a Marfan syndrome patient undergoing aneurysm repair surgery was studied.
Project description:Although abnormal TGFbeta signaling is observed in several heritable forms of thoracic aortic aneurysms and dissections including Marfan syndrome, the precise role of TGFbeta signaling in aortic disease progression is still disputed. Using a mouse genetic approach and quantitative isobaric labeling proteomics, we sought to investigate the role of TGFbeta signaling in molecular pathways of pathogenesis associated with development of aortic aneurysm and aortic rupture. This study reports an isoform-specific effect of TGFbeta in MFS aortic disease and the effects of deleting the first hybrid domain of fibrillin-1 on TGFbeta signaling. Distinct molecular differences in mouse models of aneurysm (Fbn_GT-8_plus), of aneurysm and rupture (Fbn1_GT-8_H1delta), and of microdissection (Fbn1_H1delta_plus) were identified, which associated with TGFbeta signaling and extracellular matrix composition, possibly contributing to the development of dissection and rupture. These findings offer new insights into the pathophysiological mechanisms that potentially drive initiation of aortic dissection and could pave the way for development of new treatment targets of aortic disease.
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:To improve our limited understanding of the pathogenesis of thoracic aortic aneurysm (TAA) leading to acute aortic dissection, we used single-cell RNA sequencing to profile disease-relevant transcriptomic changes of aortic cell populations in a well-characterized mouse model of the most commonly diagnosed form of Marfan syndrome (MFS). As result,MFSmod were identified only in the aorta of Fbn1mgR/mgR mice. In situ hybridizations of diagnostic transcripts located MFSmod cells to the intima of Fbn1mgR/mgR aortas. Consistent with angiotensin II type I receptor (At1r) contribution to TAA development, MFSmod cells were absent in the aorta of Fbn1mgR/mgR mice treated with the At1r antagonist losartan. Altogether, our findings indicate that a discrete dynamic alteration of aortic cell identity is associated with dissecting TAA in MFS mice and increased risk of aortic dissection in MFS patients.
Project description:Vascular smooth muscle cell (VSMC) differentiation reprogramming plays an essential role in abdominal aortic aneurysm (AAA). However, the underlying mechanisms are still indistinct. FAM3A (family with sequence similarity 3, member A) is a newly identified metabolism regulator. We examined FAM3A expression and the downstream pathways affected by FAM3A in AAA, and how FAM3A regulated VSMC differentiation. We found that overexpression or supplement of FAM3A significantly attenuated the progression of AAA, manifested by maintenance of VSMC well-differentiation state and inhibition of VSMC transformation towards macrophage-, chondrocyte-, osteogenic-, mesenchymal-, and fibroblast-like cell subpopulations. Importantly, FAM3A induced a decrease in Krüppel-like factor 4 (KLF4) phosphorylation (Ser254) level, leading to its ubiquitination and a weakened nuclear localization. Our findings identify FAM3A as a novel VSMC fate-shaping regulator in AAA and unveil the underpinning mechanism associated with KLF4 ubiquitination and stability, which could develop new strategies based on FAM3A to restore VSMC homeostasis in AAA.
Project description:Using Cdh5-Cre and Sm22-Cre transgenes to characterize the impact of disruption of the angiotensin II type 1a receptor (AT1ar) in vascular endothelial and smooth muscle cells, respectively, of wild type (WT) mice compared to fibrillin-1 hypomorphic mice (Fbn1mgR/mgR mice) that replicate early onset progressively severe Marfan syndrome (MFS) with dissecting thoracic aortic aneurysm (TAA).
Project description:Smooth muscle cell TGFβ signaling is one of the primary drivers of smooth muscle cell maturation. Inhibition of smooth muscle cell TGFβ signaling in hyperlipidemic mice induces vessel wall inflammation and vessel wall dilation/dissection and leads aortic aneurysm. We performed bulk RNAseq method to examine smooth muscle cell gene expression profile using fresh human tissues from normal aortic media smooth muscle cells and aneurysm aortic media smooth muscle cells.