Discovering the Genomic Architecture of Cell-Type Specific Gene Regulation Using Genetically Diverse Strains of Mice

Abstract

In developed nations, thrombosis remains the most common cause of death, with myocardial infarction (MI) and stroke causing the most fatalities in the United States. Hemostasis, the highly regulated process of clot formation and dissolution, involves the complex interactions of diverse cell types and regulatory molecules, including clotting factors, fibrinolytic proteins, as well as components packed into vascular cells such as platelets and endothelial cells. Proper balance of this system is vital to prevent blood loss and unwanted clotting. Although the mechanisms of coagulation have been well characterized, the genetic regulation of essential molecules in the cell types contributing to hemostasis has not been well understood.To address this gap, I investigated the genetic regulators of three important coagulation and fibrinolysis molecules: Coagulation Factor V (FV), Plasminogen Activator Inhibitor 1 (PAI-1), and Protein C (PC). The appropriate regulation of these molecules is necessary for promoting hemostasis and fibrinolysis (the process of dissolving a clot) in the correct balance to maintain the physiological “status-quo”. I used inbred mice with natural differences in their antigen levels to generate four genetically informative crosses. I measured the antigen levels for all three proteins in the plasma and platelets of the strains and received genotyping data using miniMUGA to use in Quantitative Trait Loci (QTL) analyses to discover unique genetic regulators. This approach revealed a significant locus on Chromosome 1 when analyzing the plasma FV in one cross, and one significant and one suggestive locus when sex was included as a covariate for platelet FV. For platelet PAI-1, a major locus on Chromosome 5 was identified in all 4 crosses with suggestive loci identified in three crosses. Lastly, a suggestive locus on Chromosome 7 when using sex as an additive covariate was found when analyzing PC levels in the plasma. My findings offer improved insight into the cell-type specific regulatory pathways of these essential coagulation molecules. Enhanced understanding of physiological and pathogenic regulatory pathways may lead to future novel therapeutic strategies for humans.