Juho Heliste1, Himanshu Chheda2, Ilkka Paatero3, Tiina A Salminen4, Yevhen Akimov2, Jere Paavola5, Klaus Elenius6, Tero Aittokallio7. 1. Institute for Molecular Medicine Finland, FIMM, University of Helsinki, Biomedicum 2U, Tukholmankatu 8, FI-00290 Helsinki, Finland; Institute of Biomedicine, University of Turku, Kiinamyllynkatu 10, FI-20014 Turku, Finland; Turku Doctoral Programme of Molecular Medicine, University of Turku, Turku, Finland. 2. Institute for Molecular Medicine Finland, FIMM, University of Helsinki, Biomedicum 2U, Tukholmankatu 8, FI-00290 Helsinki, Finland. 3. Turku Bioscience Centre, University of Turku and Åbo Akademi University, Tykistökatu 6, FI-20520 Turku, Finland. 4. Structural Bioinformatics Laboratory, Biochemistry, Faculty of Science and Engineering, Åbo Akademi University, Tykistökatu 6, FI-20520 Turku, Finland. 5. Unit of Cardiovascular Research, Minerva Foundation Institute for Medical Research, Biomedicum 2U, Tukholmankatu 8, FI-00290 Helsinki, Finland. 6. Institute of Biomedicine, University of Turku, Kiinamyllynkatu 10, FI-20014 Turku, Finland; Turku Bioscience Centre, University of Turku and Åbo Akademi University, Tykistökatu 6, FI-20520 Turku, Finland; Medicity Research Laboratories, University of Turku, Tykistökatu 6, FI-20520 Turku, Finland; Department of Oncology, Turku University Hospital, PO Box 52, FI-20521 Turku, Finland. 7. Institute for Molecular Medicine Finland, FIMM, University of Helsinki, Biomedicum 2U, Tukholmankatu 8, FI-00290 Helsinki, Finland; Department of Mathematics and Statistics, University of Turku, Vesilinnantie 5, FI-20014 Turku, Finland. Electronic address: tero.aittokallio@fimm.fi.
Abstract
BACKGROUND: To tackle the missing heritability of sporadic heart failure, we screened for novel heart failure-associated genetic variants in the Finnish population and functionally characterized a novel variant in vitro and in vivo. METHODS AND RESULTS: Heart failure-associated variants were screened in genotyping array data of the FINRISK study, consisting of 994 cases and 20,118 controls. Based on logistic regression analysis, a potentially damaging variant in TRIM55 (rs138811034), encoding an E140K variant, was selected for validations. In HL-1 cardiomyocytes, we used CRISPR/Cas9 technology to introduce the variant in the endogenous locus, and additionally TRIM55 wildtype or E140K was overexpressed from plasmid. Functional responses were profiled using whole-genome RNA sequencing, RT-PCR and Western analyses, cell viability and cell cycle assays and cell surface area measurements. In zebrafish embryos, cardiac contractility was measured using videomicroscopy after CRISPR-mediated knockout of trim55a or plasmid overexpression of TRIM55 WT or E140K. Genes related to muscle contraction and cardiac stress were highly regulated in Trim55 E140K/- cardiomyocytes. When compared to the WT/WT cells, the variant cells demonstrated reduced viability, significant hypertrophic response to isoproterenol, p21 protein overexpression and impaired cell cycle progression. In zebrafish embryos, the deletion of trim55a or overexpression of TRIM55 E140K reduced cardiac contractility as compared to embryos with wildtype genotype or overexpression of WT TRIM55, respectively. CONCLUSIONS: A previously uncharacterized TRIM55 E140K variant demonstrated a number of functional implications for cardiomyocyte functions in vitro and in vivo. These findings suggest a novel role for TRIM55 polymorphism in predisposing to heart failure.
BACKGROUND: To tackle the missing heritability of sporadic heart failure, we screened for novel heart failure-associated genetic variants in the Finnish population and functionally characterized a novel variant in vitro and in vivo. METHODS AND RESULTS:Heart failure-associated variants were screened in genotyping array data of the FINRISK study, consisting of 994 cases and 20,118 controls. Based on logistic regression analysis, a potentially damaging variant in TRIM55 (rs138811034), encoding an E140K variant, was selected for validations. In HL-1 cardiomyocytes, we used CRISPR/Cas9 technology to introduce the variant in the endogenous locus, and additionally TRIM55 wildtype or E140K was overexpressed from plasmid. Functional responses were profiled using whole-genome RNA sequencing, RT-PCR and Western analyses, cell viability and cell cycle assays and cell surface area measurements. In zebrafish embryos, cardiac contractility was measured using videomicroscopy after CRISPR-mediated knockout of trim55a or plasmid overexpression of TRIM55 WT or E140K. Genes related to muscle contraction and cardiac stress were highly regulated in Trim55 E140K/- cardiomyocytes. When compared to the WT/WT cells, the variant cells demonstrated reduced viability, significant hypertrophic response to isoproterenol, p21 protein overexpression and impaired cell cycle progression. In zebrafish embryos, the deletion of trim55a or overexpression of TRIM55 E140K reduced cardiac contractility as compared to embryos with wildtype genotype or overexpression of WT TRIM55, respectively. CONCLUSIONS: A previously uncharacterized TRIM55 E140K variant demonstrated a number of functional implications for cardiomyocyte functions in vitro and in vivo. These findings suggest a novel role for TRIM55 polymorphism in predisposing to heart failure.