Uncovering the Effects of Estrogen in an iPSC Derived-Vascular Smooth Muscle Model of Marfan Syndrome.

The phenotype and severity of cardiovascular diseases, such as a thoracic aortic aneurysm and dissection and atherosclerosis, differ between females and males. Notably, coronary artery dissection risk increases four-fold in women during late pregnancy and postpartum, suggesting that female sex hormones such as estrogen may play a role in vascular pathophysiology, yet are considered protective under most other circumstances. This paradox underscores the fact that the effect of estrogen on the vasculature is not fully understood at a molecular level, and most previous work in this area has been done using immortalized cell lines or animal models, which may not accurately model human responses. Furthermore, examining these effects in genetic diseases such as Marfan syndrome (MFS) allows us to view these effects in an aneurysm phenotypic model. Marfan syndrome is a connective tissue disorder caused by a mutation in the fibrillin-1 gene. Individuals typically develop aortic root aneurysms with aortic disruption and rupture that remains a leading cause of death. Here, we used Healthy and MFS iPSC-derived vascular smooth muscle cells (iVSMCs) to examine the effects of estrogen. Healthy and MFS IPSC's were differentiated into iVSMCs for 21 days then treated with estrogen for 72hrs. Immunofluorescence of smooth muscle markers and contractility assays were conducted to confirm a contractile vascular smooth muscle phenotype. A proteomic profile was established to evaluate molecular differences. Peptide data was collected using a Thermo Fusion Lumos Orbitrap mass spectrometer. Data were analyzed using the DIA-Neural networks software. We showed expression of smooth muscle markers and contractile response to stimuli. MFS iVSMCs showed decreased contractility response and a decrease in FBN1 expression compared to healthy control (MFS iVSMC vs Control iVMSC of-1.4). The proteomic profile revealed an upregulation in proteins related to elastin fiber formation and cell adhesion in both Healthy and Marfan iVSMCs following estrogen treatment. FBN1 expression increased in response to estrogen in both Healthy and Marfan iVSMC. As well as increases in Lysyl Oxidase and TGFB2 expression in MFS iVSMC following treatment. We also see a downregulation of collagen expression and RNA synthesis in healthy iVSMCs. These findings will allow us to gain a greater understanding of the complex interaction estrogen has on the vasculature and to determine their role in cardiovascular disease risk.