The purpose of this proposal is to define the influence of microRNA expression on specific changes in endothelial cell function that occur in response to shear stress forces. Shear stress forces, generated by blood flow, play an important role in the regulation of vascular tone, vascular remodeling, and the focal development of atherosclerotic lesions. In the arterial tree, endothelial cells are exposed to different shear stress forces that induce distinct effects on gene expression and function. Unidirectional shear stress, which occurs in the straight part of the tree, elicits a change in endothelial gene expression that is generally anti-inflammatory and atheroprotective. In contrast, oscillatory shear stress, which occurs at branch points in the arterial tree, induces an overall pro-inflammatory and proatherosclerotic response. MicroRNAs (miRNAs) are a recently recognized class of short (19-25 nt), single stranded, noncoding RNAs that have become a major focus in molecular biology research because they posttranscriptional regulate the expression of genes involved in an array of cell functions, including differentiation, growth, proliferation, and apoptosis. Although an important role for miRNA expression has been demonstrated for various biological processes, including cardiogenesis and angiogenesis, data on the role of specific miRNAs in endothelial cell biology is currently limited. In preliminary studies of human endothelial cells subjected to prolonged unidirectional shear stress (24 hrs, 15 dynes/cm2), a group of miRNAs was identified whose expression was significantly upregulated in response to this stimulus, suggesting that these miRNAs are important in regulating gene expression and function in endothelial cells. To further define the role of miRNA expression in modulating shear stress-induced changes in endothelial cell biology, the function of one highly shear-responsive miRNA, miR-155, will be studied. Specifically, the proposed research will define the impact of miR-155-target gene interaction on endothelial cell apoptosis, barrier function and migration. To study the mechanism by which miR-155 modulates apoptosis, we will focus on the SHIP1/PI3K/Akt pathway. To study the mechanism by which miR-155 modulates endothelial monolayer permeability and migration, we will focus on the RhoA/Rho kinase pathway. We will test the influence of miR- 155 on these critical pathways by experimentally manipulating expression of miR-155, its target gene, or members of the pathway that are downstream of the miRNA-target gene interaction. Subsequently, the effect of these manipulations on endothelial cell apoptosis, monolayer permeability, and migration will be quantified. Finally, the association between shear-induced miR-155 expression and activity of endothelial cell regulatory pathways will be studied in vivo, in a mouse model of altered aortic flow. We anticipate that these studies will help address a deficit in our knowledge about the function of miRNAs in endothelial cells and will enhance our understanding of the mechanisms by which shear stress forces modulate vascular disease.
Coronary atherosclerotic heart disease is an inflammatory disease that is the greatest cause of mortality in the U.S. Although the etiology of atherosclerosis is related to risk factors, such as diabetes, hypertension, hypercholesterolemia, and smoking, the inflammatory process occurs preferentially in arterial regions associated with low and disturbed blood flow while sparing the undisturbed flow regions, indicating that blood flow patterns are essential to the disease process. The purpose of this project is to examine the mechanisms by which an important new class of regulatory molecules, known as microRNAs, modulate vascular gene expression and function in response to flow.
|Mitchell, Adam J; Gray, Warren D; Schroeder, Max et al. (2016) Pleomorphic Structures in Human Blood Are Red Blood Cell-Derived Microparticles, Not Bacteria. PLoS One 11:e0163582|
|Mitchell, Adam J; Gray, Warren D; Hayek, Salim S et al. (2016) Platelets confound the measurement of extracellular miRNA in archived plasma. Sci Rep 6:32651|
|Mitchell, Adam J; Alexy, Tamas; Rubinsztain, Leon et al. (2016) Rheumatoid Arthritis Presenting as Acute Myopericarditis. Am J Med 129:e17-8|
|Gray, Warren D; Mitchell, Adam J; Searles, Charles D (2015) An accurate, precise method for general labeling of extracellular vesicles. MethodsX 2:360-7|
|Hudson, Matthew B; Woodworth-Hobbs, Myra E; Zheng, Bin et al. (2014) miR-23a is decreased during muscle atrophy by a mechanism that includes calcineurin signaling and exosome-mediated export. Am J Physiol Cell Physiol 306:C551-8|
|Alexy, Tamas; Rooney, Kimberly; Weber, Martina et al. (2014) TNF-? alters the release and transfer of microparticle-encapsulated miRNAs from endothelial cells. Physiol Genomics 46:833-40|
|Alexy, Tamas; James, Amanda Marie; Searles, Charles D (2014) Shear sensitive microRNAs and atherosclerosis. Biorheology 51:147-58|
|Weber, Martina; Kim, Sinae; Patterson, Nicole et al. (2014) MiRNA-155 targets myosin light chain kinase and modulates actin cytoskeleton organization in endothelial cells. Am J Physiol Heart Circ Physiol 306:H1192-203|
|Finn, Nnenna A; Searles, Charles D (2013) Using information theory to assess the communicative capacity of circulating microRNA. Biochem Biophys Res Commun 440:1-7|
|Finn, Nnenna A; Eapen, Danny; Manocha, Pankaj et al. (2013) Coronary heart disease alters intercellular communication by modifying microparticle-mediated microRNA transport. FEBS Lett 587:3456-63|
Showing the most recent 10 out of 13 publications