Knock-in mice harboring a Ca2+ desensitizing mutation in cardiac troponin C develop early onset dilated cardiomyopathy

McConnell, Bradley K.; Singh, Sonal; Fan, Qingjun; Hernández, A. F. Valencia; Portillo, Jesus; Reiser, Peter J.; Tikunova, Svetlana B.

doi:10.3389/fphys.2015.00242

Cited by 9 publications

(23 citation statements)

References 55 publications

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“…Consistent with the results from our previous study (McConnell et al . ), mean heart mass was significantly greater (46%) in D73N mice than in WT mice. The mean heart mass/body mass ratio was also significantly greater (48%) in D73N mice.…”

Section: Resultsmentioning

confidence: 85%

“…Previously, we determined that none of the homozygous D73N knock‐in mice survived longer than 1 day (McConnell et al . ). Thus, all of the D73N knock‐in mice in this study were heterozygous.…”

Section: Methodsmentioning

confidence: 97%

“…The ratio of ss/cTnC transcript with the D73N mutation to total ss/cTnC transcript in the soleus muscle of D73N mice was estimated by RT‐PCR using TNNC1 sequence‐specific primers followed by digestion of RT‐PCR product by the restriction enzyme Kpn I, as previously described for cardiac muscle (McConnell et al . ).…”

Section: Methodsmentioning

confidence: 97%

“…Recently, we evaluated the effects of desensitizing the regulatory N‐domain of ss/cTnC to Ca 2+ (by the D73N mutation) on cardiac muscle function (McConnell et al . ). The D73N mutation is not known to be associated with striated muscle diseases in humans, and was rationally designed by us to test whether desensitizing ss/cTnC to Ca 2+ can trigger the pathogenesis of dilatated cardiomyopathy (DCM).…”

Section: Introductionmentioning

confidence: 97%

“…Our results indicated that heterozygous knock‐in mice harbouring the D73N mutation in ss/cTnC develop cardiac muscle abnormalities similar to that of human patients with DCM, including higher mortality, increased heart weight‐to‐body weight ratio, increased left ventricular internal dimensions with thinner walls, reduced ejection fraction and fractional shortening, and electrophysiological abnormalities (McConnell et al . ). The consequences of the D73N mutation were consistent with results from a number of studies showing that desensitizing cardiac muscle to Ca 2+ could be detrimental to the physiological function of the heart (see reviews by Kimura, ; Willott et al .…”

Section: Introductionmentioning

confidence: 97%

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Desensitizing mouse cardiac troponin C to calcium converts slow muscle towards a fast muscle phenotype

Tikunova¹,

Belevych

Doan

et al. 2018

The Journal of Physiology

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The missense mutation, D73N, in mouse cardiac troponin C has a profound impact on cardiac function, mediated by a decreased myofilament Ca sensitivity. Mammalian cardiac muscle and slow skeletal muscle normally share expression of the same troponin C isoform. Therefore, the objective of this study was to determine the consequences of the D73N mutation in skeletal muscle, as a potential mechanism that contributes to the morbidity associated with heart failure or other conditions in which Ca sensitivity might be altered. Effects of the D73N mutation on physiological properties of mouse soleus muscle, in which slow-twitch fibres are prevalent, were examined. The mutation resulted in a rightward shift of the force-stimulation frequency relationship, and significantly faster kinetics of isometric twitches and tetani in isolated soleus muscle. Furthermore, soleus muscles from D73N mice underwent a significantly greater reduction in force during a fatigue test. The mutation significantly reduced slow fibre mean cross-sectional area without affecting soleus fibre type composition. The effects of the mutation on Ca sensitivity of force development in soleus skinned slow and fast fibres were also examined. As expected, the D73N mutation did not affect the Ca sensitivity of force development in fast fibres but resulted in substantially decreased Ca sensitivity in slow fibres. The results demonstrate that a point mutation in a single constituent of myofilaments (slow/cardiac troponin C) led to major changes in physiological properties of skeletal muscle and converted slow muscle toward a fast muscle phenotype with reduced fatigue resistance and Ca sensitivity of force generation.

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Section: Resultsmentioning

confidence: 85%

Section: Methodsmentioning

confidence: 97%

Section: Methodsmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 97%

See 3 more Smart Citations

Desensitizing mouse cardiac troponin C to calcium converts slow muscle towards a fast muscle phenotype

Tikunova¹,

Belevych

Doan

et al. 2018

The Journal of Physiology

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Adaptative Steered Molecular Dynamics Study of Mutagenesis Effects on Calcium Affinity in the Regulatory Domain of Cardiac Troponin C

Hantz

Lindert

2021

J. Chem. Inf. Model.

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Calcium-dependent cardiac muscle contraction is regulated by the protein complex troponin (cTn) and specifically by the regulatory N-terminal domain (N-cTnC) which contains one active Ca 2+ binding site (site II). It has been previously shown that cardiac muscle contractility and functionality is affected by mutations in N-cTnC which alter calcium binding affinity. Here, we describe the application of adaptive steered molecular dynamics to characterize the influence of N-cTnC mutations on site II calcium binding affinity. We observed the correct trends for all of the studied calcium sensitizing and desensitizing mutants, in conjunction with loop II perturbations. Additionally, the potential of mean force accuracy was shown to increase substantially with increasingly slower speeds and using fewer trajectories. This study presents a novel approach to computationally estimate the Ca 2+ binding affinity of N-cTnC structures and is a valuable potential tool to support the design and characterization of novel mutations with potential therapeutic benefits.

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Computational Exploration and Characterization of Potential Calcium Sensitizing Mutations in Cardiac Troponin C

Hantz

Lindert

2022

J. Chem. Inf. Model.

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Calcium-dependent heart muscle contraction is regulated by the cardiac troponin protein complex (cTn) and specifically by the N-terminal domain of its calcium binding subunit (cNTnC). cNTnC contains one calcium binding site (site II), and altered calcium binding in this site has been studied for decades. It has been previously shown that cNTnC mutants, which increase calcium sensitization may have therapeutic benefits, such as restoring cardiac muscle contractility and functionality post-myocardial infarction events. Here, we computationally characterized eight mutations for their potential effects on calcium binding affinity in site II of cNTnC. We utilized two distinct methods to estimate calcium binding: adaptive steered molecular dynamics (ASMD) and thermodynamic integration (TI). We observed a sensitizing trend for all mutations based on the employed ASMD methodology. The TI results showed excellent agreement with experimentally known calcium binding affinities in wild-type cNTnC. Based on the TI results, five mutants were predicted to increase calcium sensitivity in site II. This study presents an interesting comparison of the two computational methods, which have both been shown to be valuable tools in characterizing the impacts of calcium sensitivity in mutant cNTnC systems.

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Knock-in mice harboring a Ca2+ desensitizing mutation in cardiac troponin C develop early onset dilated cardiomyopathy

Cited by 9 publications

References 55 publications

Desensitizing mouse cardiac troponin C to calcium converts slow muscle towards a fast muscle phenotype

Desensitizing mouse cardiac troponin C to calcium converts slow muscle towards a fast muscle phenotype

Adaptative Steered Molecular Dynamics Study of Mutagenesis Effects on Calcium Affinity in the Regulatory Domain of Cardiac Troponin C

Computational Exploration and Characterization of Potential Calcium Sensitizing Mutations in Cardiac Troponin C

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