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MUTATIONS IN SCAP AND AGXT2 REVEALED BY EXOME SEQUENCING A PEDIGREE WITH PREMATURE MYOCARDIAL INFARCTION
143 JACC March 21, 2017 Volume 69, Issue 11
Acute and Stable Ischemic Heart Disease MUTATIONS IN SCAP AND AGXT2 REVEALED BY EXOME SEQUENCING A PEDIGREE WITH PREMATURE MYOCARDIAL INFARCTION Poster Contributions Poster Hall, Hall C Saturday, March 18, 2017, 9:45 a.m.-10:30 a.m. Session Title: From Diet to Drugs: Mechanistic Insight Into Ischemic Heart Disease Abstract Category: 1. Acute and Stable Ischemic Heart Disease: Basic Presentation Number: 1202-297 Authors: Chong You Lee, Yuanfeng Gao, Junxian Song, Sufang Li, Yuxia Cui, Hong Chen, Department of Cardiology, Peking University People’s Hospital, Beijing, People’s Republic of China Bacground: To investigate the causative genes of myocardial infarction (MI) in a pedigree with multiple members with premature myocardial infarction (PMI) by whole-exome sequencing and functional verification.
Methods: PMI was defined by MI diagnosed before 50 for men and 60 for women. Peripheral blood of all the family members (n=17) was obtained under informed consent for DNA extraction. Whole-exome sequencing was performed on 8 individuals from a PMI pedigree with two siblings diagnosed with MI before the age of 45. Bioinformatics analysis served as a tool for causative gene screening. Another 100 PMI patients were also enrolled for population validation of the potential causative genes. Finally, the potential causative genes were introduced into corresponding model cell lines by CRISPR-Cas9, after which the functional consequences of the mutations were evaluated by western-blot and Elisa. Results: Upon exome-sequencing and Bioinformatics analysis, two variants in SCAP (c.3035C>T, p.Ala1012Val) and AGXT2 (c.1103C>T, p.Ala338Val) were identified as potential causative mutation for PMI. It was noteworthy that only patients that meet the diagnosis of PMI (n=2) harbored two variants all together, while other MI patients or members carried only one or no above variants. Population validation revealed another variant on SCAP (c.1403 T>C, p.Val468Ala), which was absent in 28, 000 east-Asian population. However, no potential causative mutation on AGXT2 was found in the present population. Further, the two variants on SCAP and AGXT2 were introduced into H293T and EA. hy926 cell lines respectively. Functional study revealed that the SCAP mutation impaired SCAP-SREBP feedback mechanism which may lead to a “consititutive activation” effect of cholesterol synthesis related genes, while the AGXT2 mutation caused a deficiency of its aminotransferase activity which would lead to a downregulation of NO production by ADMA accumulation. Conclusions: SCAP and AGXT2 are potential causative genes for MI. Digenic mutation carriers may manifest a more severe phenotype, namely premature MI. In addition, the present results also hints the role of digenic mutations in the molecular genetic mechanism of PMI.
Acute and Stable Ischemic Heart Disease MUTATIONS IN SCAP AND AGXT2 REVEALED BY EXOME SEQUENCING A PEDIGREE WITH PREMATURE MYOCARDIAL INFARCTION Poster Contributions Poster Hall, Hall C Saturday, March 18, 2017, 9:45 a.m.-10:30 a.m. Session Title: From Diet to Drugs: Mechanistic Insight Into Ischemic Heart Disease Abstract Category: 1. Acute and Stable Ischemic Heart Disease: Basic Presentation Number: 1202-297 Authors: Chong You Lee, Yuanfeng Gao, Junxian Song, Sufang Li, Yuxia Cui, Hong Chen, Department of Cardiology, Peking University People’s Hospital, Beijing, People’s Republic of China Bacground: To investigate the causative genes of myocardial infarction (MI) in a pedigree with multiple members with premature myocardial infarction (PMI) by whole-exome sequencing and functional verification.
Methods: PMI was defined by MI diagnosed before 50 for men and 60 for women. Peripheral blood of all the family members (n=17) was obtained under informed consent for DNA extraction. Whole-exome sequencing was performed on 8 individuals from a PMI pedigree with two siblings diagnosed with MI before the age of 45. Bioinformatics analysis served as a tool for causative gene screening. Another 100 PMI patients were also enrolled for population validation of the potential causative genes. Finally, the potential causative genes were introduced into corresponding model cell lines by CRISPR-Cas9, after which the functional consequences of the mutations were evaluated by western-blot and Elisa. Results: Upon exome-sequencing and Bioinformatics analysis, two variants in SCAP (c.3035C>T, p.Ala1012Val) and AGXT2 (c.1103C>T, p.Ala338Val) were identified as potential causative mutation for PMI. It was noteworthy that only patients that meet the diagnosis of PMI (n=2) harbored two variants all together, while other MI patients or members carried only one or no above variants. Population validation revealed another variant on SCAP (c.1403 T>C, p.Val468Ala), which was absent in 28, 000 east-Asian population. However, no potential causative mutation on AGXT2 was found in the present population. Further, the two variants on SCAP and AGXT2 were introduced into H293T and EA. hy926 cell lines respectively. Functional study revealed that the SCAP mutation impaired SCAP-SREBP feedback mechanism which may lead to a “consititutive activation” effect of cholesterol synthesis related genes, while the AGXT2 mutation caused a deficiency of its aminotransferase activity which would lead to a downregulation of NO production by ADMA accumulation. Conclusions: SCAP and AGXT2 are potential causative genes for MI. Digenic mutation carriers may manifest a more severe phenotype, namely premature MI. In addition, the present results also hints the role of digenic mutations in the molecular genetic mechanism of PMI.