Project description:We are interested in the role of NOTCH1 and Shear Stress in Aortic Valve Endothelium. Primary human aortic valve endothelium was subjected to 4 conditions in vitro. 1) Control siRNA, No shear stress. 2) NOTCH1 siRNA, No shear stress. 3) Control siRNA, 15 dynes/cm2 shear stress. 4) NOTCH1 siRNA, 15 dynes/cm2 shear stress. Triplicates of each condition were pooled for library perp and sequencing
Project description:The lymphatic system removes fluid from the interstitial space and returns it to the blood with a tremendous capacity: during inflammation, lymph flow rates can increase dramatically; however, during chronic lymphedema, there is little or no flow. The ability of lymphatic endothelium to sense and actively regulate this function is unknown, and shear stress is likely a key indicator of lymph flow. We profiled gene expression in human dermal microvascular lymphatic endothelial cells exposed to 0, 2 and 20 dyn/cm2 shear stress as representative of chronic lymphedema, normal, and acute inflammatory conditions, respectively. We found important adaptive responses correlated to multiple aspects of lymphatic function. Importantly, shear stress upregulated intracellular water and solute transporters while decreasing cell-cell adhesion and basement membrane components and increasing cell-matrix interactions. This data indicate that during high loading conditions, both passive and active drainage function increases, while conversely when fluid drainage is blocked, transport function is diminished in the lymphatic endothelium. These data demonstrate the first functional-adaptive response of lymphatic endothelium to flow conditions, thus indicating that the lymphatic endothelium plays an active role in regulating their function. Keywords: Shear stress, dose response, cell type comparison Lymphatic endothelial cells were subjected to 0, 2, or 20 dyn/cm2 shear stress; blood endothelial cells were subjected to 0 or 20 dyn/cm2 shear stress. Four samples were used for each cell type/shear level group for a total of 20 samples. Each sample was independently compared to human universal reference RNA via two-color microarray analysis for a total of 20 arrays. In all cases, the experimental samples were labeled with Cy5 dye while the reference RNA was labeled with Cy3.
Project description:The lymphatic system removes fluid from the interstitial space and returns it to the blood with a tremendous capacity: during inflammation, lymph flow rates can increase dramatically; however, during chronic lymphedema, there is little or no flow. The ability of lymphatic endothelium to sense and actively regulate this function is unknown, and shear stress is likely a key indicator of lymph flow. We profiled gene expression in human dermal microvascular lymphatic endothelial cells exposed to 0, 2 and 20 dyn/cm2 shear stress as representative of chronic lymphedema, normal, and acute inflammatory conditions, respectively. We found important adaptive responses correlated to multiple aspects of lymphatic function. Importantly, shear stress upregulated intracellular water and solute transporters while decreasing cell-cell adhesion and basement membrane components and increasing cell-matrix interactions. This data indicate that during high loading conditions, both passive and active drainage function increases, while conversely when fluid drainage is blocked, transport function is diminished in the lymphatic endothelium. These data demonstrate the first functional-adaptive response of lymphatic endothelium to flow conditions, thus indicating that the lymphatic endothelium plays an active role in regulating their function. Keywords: Shear stress, dose response, cell type comparison
Project description:Many studies have characterized the results of shear stress changes on cultured endothelial cells in different bioreactor systems. However it is still unclear how an invasive intervention like stent procedure may influence the transcriptional response of endothelium. To study the simultaneous effects of shear stress changes and stent application on endothelial gene expression, we have used an experimental apparatus of laminar flow bioreactor (LFB) system with human cultured endothelial cells exposed or not exposed to stent procedure with different flow conditions. Microarray analysis was evaluated in each experimental protocol.
Project description:The role of shear stress, the frictional force of blood flow, on the endothelium has been well documented. Differences in shear stress can have profound effects on endothelial and blood vessel biology. Endothelial cells (ECs), termed endocardial ECs, line the heart chambers and are exposed to complex shear stress patterns. While it has been demonstrated that shear stress is important for heart development, little has been shown on the role of shear stress on adult ECs. 4D-MRI studies demonstrate regional differences in blood residence time. We sought to determine the effect of regional differences in endocardial shear stress on the endocardial transcriptome using RNA sequencing (RNA-seq) on 3 different regions (apex, mid-ventricle, outflow tract) from 8 adult pigs, for a total of 24 RNA-seq assays.
Project description:Many studies have characterized the results of shear stress changes on cultured endothelial cells in different bioreactor systems. However it is still unclear how an invasive intervention like stent procedure may influence the transcriptional response of endothelium. To study the simultaneous effects of shear stress changes and stent application on endothelial gene expression, we have used an experimental apparatus of laminar flow bioreactor (LFB) system with human cultured endothelial cells exposed or not exposed to stent procedure with different flow conditions. Microarray analysis was evaluated in each experimental protocol. HUVECs (2nd and 5th passage) covered on Thermanox slides were submitted to static, low and physiological (0, 1, 5 and 10 dyne/cm2) shear stress in absence (AS) or presence (PS) of stent in LFB system for 24h. Affymetryx analysis has been performed in duplicate by Consortium for Genomic Technologies (Cogentech; Milan, Italy)
Project description:Background: Hemodynamic forces exert a profound influence on endothelial cell signaling and, when abnormal, contribute centrally to human vascular disease. Pulmonary arterial hypertension (PAH) is characterized by both hemodynamic derangement and pulmonary arterial endothelial cell (PAEC) dysfunction. Despite importance in disease initiation and progression, the combined effects of shear and pressure forces on PAEC biology remain incompletely understood, particularly in the context of PAH. Methods: PAECs obtained at explant from controls and from patients with idiopathic or congenital heart disease-associated PAH (CHD-PAH) were cultured in a custom resistor-coupled microfluidic platform and exposed to static, low (3 dyne/cm²), or high (20 dyne/cm²) shear stress under either low or elevated (60 mmHg) pressure. After 24 hours, we assessed cellular morphology and performed systems-level transcriptomic analysis via bulk RNA sequencing, incorporating analyses of PAH subtype and donor sex. Results: PAECs (n=18 donors) aligned with flow under high, but not low, shear, and alignment was not significantly altered by disease state or pressure. Shear stress fundamentally reorganized the PAEC transcriptome and the “dose-response” to increasing shear differed across biological pathways in six statistically significant patterns. Increasing shear led to divergence in transcription between control and PAH cells, particularly in pathways involved in immune activation, stress signaling, and vascular remodeling, with subtype differences also observed. Pressure alone had modest effects on transcription, though CHD-PAH PAECs especially displayed pressure-induced stress and inflammatory signaling. We identified sexual dimorphism in the endothelial shear response, noting male cells under shear enriched for pathways involved in proliferation and inflammation and female cells enriched for lipid metabolism and stress responses. Conclusions: Shear and pressure forces profoundly influence PAEC transcription, with responses shaped by disease state, PAH subtype, and sex. These findings highlight the need for further investigation into mechanosensitive pathways in PAH as potential targets for novel therapies.