Project description:Loeys-Dietz Syndrome (LDS), caused by a spectrum of mutations in the TGF-β signaling cascade, leads to aggressive thoracic aneurysms. Given the ubiquitous nature of TGF-β signaling machinery, the exact cell type(s) responsible for initiation of LDS pathogenesis is poorly understood.
Project description:Loeys-Dietz Syndrome (LDS), caused by a spectrum of mutations in the TGF-β signaling cascade, leads to aggressive thoracic aneurysms. Given the ubiquitous nature of TGF-β signaling machinery, the exact cell type(s) responsible for initiation of LDS pathogenesis is poorly understood.
Project description:Loeys-Dietz Syndrome (LDS), caused by a spectrum of mutations in the TGF-β signaling cascade, leads to aggressive thoracic aneurysms. Given the ubiquitous nature of TGF-β signaling machinery, the exact cell type(s) responsible for initiation of LDS pathogenesis is poorly understood.
Project description:Loeys Dietz Syndrome (LDS) is a connective tissue disorder caused by mutations along the TGF-beta signaling pathway and characterized by severe aortic aneurysm and craniofacial anomalies. Patients with LDS Type II (LDS2), caused by mutations in the TGFBR2 gene also exhibit enamel defects. A mouse model for LDS2, harboring a G357W mutation in the Tgfbr2 gene, recapitulates the cardiovascular, craniofacial and dental phenotype of the disease. This transcriptomic analysis aimed at identifying genes that are differentially regulated in first molars of Tgfbr2-G357W/+ mice at postnatal day 5 and 11. Total RNA was extracted from enamel organs from Tgfbr2-G357W/+ mice (LDSR2, KI) and Tgfbr2-+/+ wild-type littermates (WT).
Project description:Loeys-Dietz syndrome (LDS) is a hereditary aneurysm disorder caused by mutations that impair transforming growth factor-β (TGF-β) signaling. Although LDS patients develop aneurysms throughout the arterial tree, the aortic root is a site of increased risk. In order to identify molecular determinants of this regional vulnerability, we investigated the transcriptional heterogeneity of vascular smooth muscle cells (VSMCs) in the aorta of Tgfbr1M318R/+ LDS mouse models by single cell RNA sequencing (scRNAseq) and spatial transcriptomics. Downregulation of transcripts coding for components of the extracellular matrix-receptor mechanosensing apparatus and upregulation of transcripts related to stress and inflammation were observed in all Tgfbr1M318R/+ VSMCs. However, regardless of genotype, a subset of Gata4-expressing VSMCs predominantly located in the aortic root intrinsically displayed a less differentiated, pro-inflammatory transcriptional profile. A similar population was also identified in a published scRNAseq dataset of the aorta of LDS patients via the Coordinated Gene Activity in Pattern Sets (CoGAPS)/ProjectR pipeline. Postnatal VSMC-specific Gata4 deletion resulted in reduced aortic root dilation in LDS mice, in association with decreased levels of Agtr1a and other pro-inflammatory regulators. We propose that widespread dysregulation of mechanosensitive pathways may act on regionally restricted factors that “prime” specific aortic locations to increased risk of aneurysm.
Project description:Loeys Dietz Syndrome (LDS) is a connective tissue disorder caused by mutations along the TGF-beta signaling pathway and characterized by severe aortic aneurysm and craniofacial anomalies. Patients with LDS Type II (LDS2), caused by mutations in the TGFBR2 gene also exhibit enamel defects. A mouse model for LDS2, harboring a G357W mutation in the Tgfbr2 gene, recapitulates the cardiovascular, craniofacial and dental phenotype of the disease. This transcriptomic analysis aimed at identifying genes that are differentially regulated in the enamel organ of Tgfbr2-G357W/+ mice at postnatal day 11. Total RNA was extracted from enamel organs from five Tgfbr2-G357W/+ mice (LDSR2, KI) and eight Tgfbr2-+/+ wild-type littermates (WT). This dataset indicates that the mutation in Tgfbr2 in the enamel organ minimally affects gene expression and suggests that the enamel phenotype in LDS2 is not dependent on canonical TGF-beta signaling.
Project description:Loeys Dietz Syndrome (LDS) is a connective tissue disorder caused by mutations along the TGF-beta signaling pathway and characterized by severe aortic aneurysm and craniofacial anomalies. Patients with LDS Type II (LDS2), caused by mutations in the TGFBR2 gene also exhibit enamel defects. A mouse model for LDS2, harboring a G357W mutation in the Tgfbr2 gene, recapitulates the cardiovascular, craniofacial and dental phenotype of the disease. As part of our transcriptomic analysis aimed at identifying genes that are differentially regulated in the enamel organ of Tgfbr2-G357W/+ mice at postnatal day 11, we peformed a similar analysis on the aorta transcriptome at the same age. Total RNA was extracted from aortic arches from six Tgfbr2-G357W/+ mice (LDS2, Het) and five Tgfbr2-+/+ wild-type littermates (WT). This dataset provides a comprehensive list of genes affected in the aorta of an LDS2 mouse model at a young age.
Project description:BackgroundLoeys-Dietz syndrome (LDS) is a connective tissue disorder that commonly presents with vascular abnormalities. Owing to the rarity and severity of the condition, consensus guidelines for aortic surgery thresholds vary. In addition, evaluation of coronary arteries in patients with LDS (either routinely or before aortic root surgery) remain undefined. In this case report, we discuss a patient with LDS who found to have an ectatic aortic root and a coronary artery aneurysm and discuss guidelines for evaluation and management in this patient population.Case summaryA 48-year-old woman was incidentally found to have a 45 mm ectatic aortic root during evaluation for a neck mass. As part of pre-operative evaluation for aortic root replacement, left heart catheterization revealed a left main coronary artery aneurysm. Family history revealed aortic aneurysms, sudden cardiac death, and tall height. Physical examination was notable for pectus excavatum and elongated limbs. Workup for inflammatory aetiologies of aortic root dilation was negative. Genetic testing revealed a heterozygous pathogenic TGBF3 variant, consistent with LDS Type 5. She subsequently underwent two-vessel coronary artery bypass, excision of her left main coronary artery aneurysm, and ascending aortic replacement.DiscussionIn this case, we describe a patient with LDS who was noted to have a coronary artery aneurysm, a rare finding in the initial presentation of disease. In addition, we examine guidelines regarding evaluation of management of aortic root disease and coronary aneurysms.