{'fraction_non_alphanumeric': 0.019238812212463405, 'fraction_numerical': 0.037641154328732745, 'mean_word_length': 4.805825242718447, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Abstract 401: Epigenetic Regulation At
 LRP1
 Cardiovascular Disease Risk Locus And Assessment Of Cellular Function In Human Ipscs-derived Smooth Muscle Cells


 Background/Introduction:
 Spontaneous coronary artery dissection (SCAD) is an increasingly recognized cause of myocardial infarction in young and middle-aged women. A common genetic variant, rs11172113, located in
 LRP1
 (
 low density lipoprotein receptor-related protein 1)
 first intron, was associated with several vascular diseases, including SCAD, coronary artery disease and migraine. However, the biological mechanisms through which rs11172113 influence
 LRP1
 function in the context of arterial lesions is not fully understood.
 
 
 Methods:
 We applied luciferase reporter assay to measure the different enhancer activities between 2 alleles of rs11172113 in rat SMCs and human iPSC-derived SMCs. We edited iPSCs prior to differentiation using CRISPR-Cas9 to generate 100 bp deletion of the enhancer region containing rs11172113. We also created frame-shift indels in exons 2 or 5 of
 LRP1
 in iPSCs to generate SMCs knockouts and differentiated into SMCs. We then performed a proteomic and transcriptomic characterization of
 LRP1
 knockout effect in these iPSC-derived SMCs.
 
 
 Results:
 Reporter assay confirmed that rs11172113 belongs to a genomic region showing enhancer activity of 2 alleles
 in vitro
 . The transcription factor MECP2 increased the enhancer capacity in both alleles. iPSCs with homozygous deletion of rs11172113 enhancer region presented the same pluripotency compared with wild type. We found that the deletion of rs11172113 enhancer region decreased the expression of
 LRP1
 . LRP1 knockout decreased capacity of cell proliferation and migration in iPSC derived SMCs. Transcriptomic analysis in iPSC derived SMCs suggests
 LRP1
 knockout decreased the expression of genes involved in vascular smooth muscle cells microenvironment, such as
 decorin
 (
 DCN
 ), and contraction, such as
 ryanodine receptor 2
 (
 RYR2
 ). We are currently evaluating the effect of
 LRP1
 on SMC contraction and extracellular matrix synthesis.
 
 
 Conclusions:
 We confirmed rs11172113 to regulate
 LRP1
 expression in iPSCs derived synthetic and contractile SMCs. Our results support
 LRP1
 effect on SMCs cellular function alteration as a potential mechanism in genetic susceptibility for vascular disease.
