In Vivo Analysis of Troponin C Knock-In (A8V) Mice

Evidence that TNNC1 Is a Hypertrophic Cardiomyopathy Susceptibility Gene

Adriano S. Martins, Michelle S. Parvatiyar, Han Zhong Feng, J. Martijn Bos, David Gonzalez-Martinez, Milica Vukmirovic, Rajdeep S. Turna, Marcos A. Sanchez-Gonzalez, Crystal Dawn Badger, Diego A R Zorio, Rakesh K. Singh, Yingcai Wang, J. P. Jin, Michael J. Ackerman, Jose R. Pinto

Research output: Contribution to journalArticle

22 Citations (Scopus)

Abstract

Background-Mutations in thin-filament proteins have been linked to hypertrophic cardiomyopathy, but it has never been demonstrated that variants identified in the TNNC1 (gene encoding troponin C) can evoke cardiac remodeling in vivo. The goal of this study was to determine whether TNNC1 can be categorized as an hypertrophic cardiomyopathy susceptibility gene, such that a mouse model can recapitulate the clinical presentation of the proband. Methods and Results-The TNNC1-A8V proband diagnosed with severe obstructive hypertrophic cardiomyopathy at 34 years of age exhibited mild-to-moderate thickening in left and right ventricular walls, decreased left ventricular dimensions, left atrial enlargement, and hyperdynamic left ventricular systolic function. Genetically engineered knock-in (KI) mice containing the A8V mutation (heterozygote=KI-TnC-A8V+/-; homozygote=KI-TnC-A8V+/+) were characterized by echocardiography and pressure-volume studies. Three-month-old KI-TnC-A8V+/+ mice displayed decreased ventricular dimensions, mild diastolic dysfunction, and enhanced systolic function, whereas KI-TnC-A8V+/- mice displayed cardiac restriction at 14 months of age. KI hearts exhibited atrial enlargement, papillary muscle hypertrophy, and fibrosis. Liquid chromatography-mass spectroscopy was used to determine incorporation of mutant cardiac troponin C (≈21%) into the KI-TnC-A8V+/- cardiac myofilament. Reduced diastolic sarcomeric length, increased shortening, and prolonged Ca2+ and contractile transients were recorded in intact KI-TnC-A8V+/- and KI-TnC-A8V+/+ cardiomyocytes. Ca2+ sensitivity of contraction in skinned fibers increased with mutant gene dose: KI-TnC-A8V+/+>KI-TnC-A8V+/->wild-type, whereas KI-TnC-A8V+/+ relaxed more slowly on flash photolysis of diazo-2. Conclusions-The TNNC1-A8V mutant increases the Ca2+-binding affinity of the thin filament and elicits changes in Ca2+ homeostasis and cellular remodeling, which leads to diastolic dysfunction. These in vivo alterations further implicate the role of TNNC1 mutations in the development of cardiomyopathy.

Original languageEnglish (US)
Pages (from-to)653-664
Number of pages12
JournalCirculation: Cardiovascular Genetics
Volume8
Issue number5
DOIs
StatePublished - Oct 1 2015

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Troponin C
Hypertrophic Cardiomyopathy
Mutation
Genes
Gene Knock-In Techniques
Papillary Muscles
Myofibrils
Photolysis
Homozygote
Heterozygote
Cardiomyopathies
Left Ventricular Function
Cardiac Myocytes
Liquid Chromatography
Hypertrophy
Echocardiography
Mass Spectrometry
Homeostasis
Fibrosis
Pressure

Keywords

  • Ca handling
  • calcium sensitization
  • cardiomyopathy
  • hypertrophic cardiomyopathy
  • knock-in mouse model
  • mouse
  • myofilament protein
  • TNNC1
  • troponin
  • troponin C

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine
  • Genetics(clinical)
  • Genetics

Cite this

Martins, A. S., Parvatiyar, M. S., Feng, H. Z., Bos, J. M., Gonzalez-Martinez, D., Vukmirovic, M., ... Pinto, J. R. (2015). In Vivo Analysis of Troponin C Knock-In (A8V) Mice: Evidence that TNNC1 Is a Hypertrophic Cardiomyopathy Susceptibility Gene. Circulation: Cardiovascular Genetics, 8(5), 653-664. https://doi.org/10.1161/CIRCGENETICS.114.000957

In Vivo Analysis of Troponin C Knock-In (A8V) Mice : Evidence that TNNC1 Is a Hypertrophic Cardiomyopathy Susceptibility Gene. / Martins, Adriano S.; Parvatiyar, Michelle S.; Feng, Han Zhong; Bos, J. Martijn; Gonzalez-Martinez, David; Vukmirovic, Milica; Turna, Rajdeep S.; Sanchez-Gonzalez, Marcos A.; Badger, Crystal Dawn; Zorio, Diego A R; Singh, Rakesh K.; Wang, Yingcai; Jin, J. P.; Ackerman, Michael J.; Pinto, Jose R.

In: Circulation: Cardiovascular Genetics, Vol. 8, No. 5, 01.10.2015, p. 653-664.

Research output: Contribution to journalArticle

Martins, AS, Parvatiyar, MS, Feng, HZ, Bos, JM, Gonzalez-Martinez, D, Vukmirovic, M, Turna, RS, Sanchez-Gonzalez, MA, Badger, CD, Zorio, DAR, Singh, RK, Wang, Y, Jin, JP, Ackerman, MJ & Pinto, JR 2015, 'In Vivo Analysis of Troponin C Knock-In (A8V) Mice: Evidence that TNNC1 Is a Hypertrophic Cardiomyopathy Susceptibility Gene', Circulation: Cardiovascular Genetics, vol. 8, no. 5, pp. 653-664. https://doi.org/10.1161/CIRCGENETICS.114.000957
Martins, Adriano S. ; Parvatiyar, Michelle S. ; Feng, Han Zhong ; Bos, J. Martijn ; Gonzalez-Martinez, David ; Vukmirovic, Milica ; Turna, Rajdeep S. ; Sanchez-Gonzalez, Marcos A. ; Badger, Crystal Dawn ; Zorio, Diego A R ; Singh, Rakesh K. ; Wang, Yingcai ; Jin, J. P. ; Ackerman, Michael J. ; Pinto, Jose R. / In Vivo Analysis of Troponin C Knock-In (A8V) Mice : Evidence that TNNC1 Is a Hypertrophic Cardiomyopathy Susceptibility Gene. In: Circulation: Cardiovascular Genetics. 2015 ; Vol. 8, No. 5. pp. 653-664.
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title = "In Vivo Analysis of Troponin C Knock-In (A8V) Mice: Evidence that TNNC1 Is a Hypertrophic Cardiomyopathy Susceptibility Gene",
abstract = "Background-Mutations in thin-filament proteins have been linked to hypertrophic cardiomyopathy, but it has never been demonstrated that variants identified in the TNNC1 (gene encoding troponin C) can evoke cardiac remodeling in vivo. The goal of this study was to determine whether TNNC1 can be categorized as an hypertrophic cardiomyopathy susceptibility gene, such that a mouse model can recapitulate the clinical presentation of the proband. Methods and Results-The TNNC1-A8V proband diagnosed with severe obstructive hypertrophic cardiomyopathy at 34 years of age exhibited mild-to-moderate thickening in left and right ventricular walls, decreased left ventricular dimensions, left atrial enlargement, and hyperdynamic left ventricular systolic function. Genetically engineered knock-in (KI) mice containing the A8V mutation (heterozygote=KI-TnC-A8V+/-; homozygote=KI-TnC-A8V+/+) were characterized by echocardiography and pressure-volume studies. Three-month-old KI-TnC-A8V+/+ mice displayed decreased ventricular dimensions, mild diastolic dysfunction, and enhanced systolic function, whereas KI-TnC-A8V+/- mice displayed cardiac restriction at 14 months of age. KI hearts exhibited atrial enlargement, papillary muscle hypertrophy, and fibrosis. Liquid chromatography-mass spectroscopy was used to determine incorporation of mutant cardiac troponin C (≈21{\%}) into the KI-TnC-A8V+/- cardiac myofilament. Reduced diastolic sarcomeric length, increased shortening, and prolonged Ca2+ and contractile transients were recorded in intact KI-TnC-A8V+/- and KI-TnC-A8V+/+ cardiomyocytes. Ca2+ sensitivity of contraction in skinned fibers increased with mutant gene dose: KI-TnC-A8V+/+>KI-TnC-A8V+/->wild-type, whereas KI-TnC-A8V+/+ relaxed more slowly on flash photolysis of diazo-2. Conclusions-The TNNC1-A8V mutant increases the Ca2+-binding affinity of the thin filament and elicits changes in Ca2+ homeostasis and cellular remodeling, which leads to diastolic dysfunction. These in vivo alterations further implicate the role of TNNC1 mutations in the development of cardiomyopathy.",
keywords = "Ca handling, calcium sensitization, cardiomyopathy, hypertrophic cardiomyopathy, knock-in mouse model, mouse, myofilament protein, TNNC1, troponin, troponin C",
author = "Martins, {Adriano S.} and Parvatiyar, {Michelle S.} and Feng, {Han Zhong} and Bos, {J. Martijn} and David Gonzalez-Martinez and Milica Vukmirovic and Turna, {Rajdeep S.} and Sanchez-Gonzalez, {Marcos A.} and Badger, {Crystal Dawn} and Zorio, {Diego A R} and Singh, {Rakesh K.} and Yingcai Wang and Jin, {J. P.} and Ackerman, {Michael J.} and Pinto, {Jose R.}",
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T1 - In Vivo Analysis of Troponin C Knock-In (A8V) Mice

T2 - Evidence that TNNC1 Is a Hypertrophic Cardiomyopathy Susceptibility Gene

AU - Martins, Adriano S.

AU - Parvatiyar, Michelle S.

AU - Feng, Han Zhong

AU - Bos, J. Martijn

AU - Gonzalez-Martinez, David

AU - Vukmirovic, Milica

AU - Turna, Rajdeep S.

AU - Sanchez-Gonzalez, Marcos A.

AU - Badger, Crystal Dawn

AU - Zorio, Diego A R

AU - Singh, Rakesh K.

AU - Wang, Yingcai

AU - Jin, J. P.

AU - Ackerman, Michael J.

AU - Pinto, Jose R.

PY - 2015/10/1

Y1 - 2015/10/1

N2 - Background-Mutations in thin-filament proteins have been linked to hypertrophic cardiomyopathy, but it has never been demonstrated that variants identified in the TNNC1 (gene encoding troponin C) can evoke cardiac remodeling in vivo. The goal of this study was to determine whether TNNC1 can be categorized as an hypertrophic cardiomyopathy susceptibility gene, such that a mouse model can recapitulate the clinical presentation of the proband. Methods and Results-The TNNC1-A8V proband diagnosed with severe obstructive hypertrophic cardiomyopathy at 34 years of age exhibited mild-to-moderate thickening in left and right ventricular walls, decreased left ventricular dimensions, left atrial enlargement, and hyperdynamic left ventricular systolic function. Genetically engineered knock-in (KI) mice containing the A8V mutation (heterozygote=KI-TnC-A8V+/-; homozygote=KI-TnC-A8V+/+) were characterized by echocardiography and pressure-volume studies. Three-month-old KI-TnC-A8V+/+ mice displayed decreased ventricular dimensions, mild diastolic dysfunction, and enhanced systolic function, whereas KI-TnC-A8V+/- mice displayed cardiac restriction at 14 months of age. KI hearts exhibited atrial enlargement, papillary muscle hypertrophy, and fibrosis. Liquid chromatography-mass spectroscopy was used to determine incorporation of mutant cardiac troponin C (≈21%) into the KI-TnC-A8V+/- cardiac myofilament. Reduced diastolic sarcomeric length, increased shortening, and prolonged Ca2+ and contractile transients were recorded in intact KI-TnC-A8V+/- and KI-TnC-A8V+/+ cardiomyocytes. Ca2+ sensitivity of contraction in skinned fibers increased with mutant gene dose: KI-TnC-A8V+/+>KI-TnC-A8V+/->wild-type, whereas KI-TnC-A8V+/+ relaxed more slowly on flash photolysis of diazo-2. Conclusions-The TNNC1-A8V mutant increases the Ca2+-binding affinity of the thin filament and elicits changes in Ca2+ homeostasis and cellular remodeling, which leads to diastolic dysfunction. These in vivo alterations further implicate the role of TNNC1 mutations in the development of cardiomyopathy.

AB - Background-Mutations in thin-filament proteins have been linked to hypertrophic cardiomyopathy, but it has never been demonstrated that variants identified in the TNNC1 (gene encoding troponin C) can evoke cardiac remodeling in vivo. The goal of this study was to determine whether TNNC1 can be categorized as an hypertrophic cardiomyopathy susceptibility gene, such that a mouse model can recapitulate the clinical presentation of the proband. Methods and Results-The TNNC1-A8V proband diagnosed with severe obstructive hypertrophic cardiomyopathy at 34 years of age exhibited mild-to-moderate thickening in left and right ventricular walls, decreased left ventricular dimensions, left atrial enlargement, and hyperdynamic left ventricular systolic function. Genetically engineered knock-in (KI) mice containing the A8V mutation (heterozygote=KI-TnC-A8V+/-; homozygote=KI-TnC-A8V+/+) were characterized by echocardiography and pressure-volume studies. Three-month-old KI-TnC-A8V+/+ mice displayed decreased ventricular dimensions, mild diastolic dysfunction, and enhanced systolic function, whereas KI-TnC-A8V+/- mice displayed cardiac restriction at 14 months of age. KI hearts exhibited atrial enlargement, papillary muscle hypertrophy, and fibrosis. Liquid chromatography-mass spectroscopy was used to determine incorporation of mutant cardiac troponin C (≈21%) into the KI-TnC-A8V+/- cardiac myofilament. Reduced diastolic sarcomeric length, increased shortening, and prolonged Ca2+ and contractile transients were recorded in intact KI-TnC-A8V+/- and KI-TnC-A8V+/+ cardiomyocytes. Ca2+ sensitivity of contraction in skinned fibers increased with mutant gene dose: KI-TnC-A8V+/+>KI-TnC-A8V+/->wild-type, whereas KI-TnC-A8V+/+ relaxed more slowly on flash photolysis of diazo-2. Conclusions-The TNNC1-A8V mutant increases the Ca2+-binding affinity of the thin filament and elicits changes in Ca2+ homeostasis and cellular remodeling, which leads to diastolic dysfunction. These in vivo alterations further implicate the role of TNNC1 mutations in the development of cardiomyopathy.

KW - Ca handling

KW - calcium sensitization

KW - cardiomyopathy

KW - hypertrophic cardiomyopathy

KW - knock-in mouse model

KW - mouse

KW - myofilament protein

KW - TNNC1

KW - troponin

KW - troponin C

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