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CDK9 and its repressor LARP7 modulate cardiomyocyte proliferation and response to injury in the zebrafish heart.

Matrone G, Wilson KS, Maqsood S, Mullins JJ, Tucker CS, Denvir MA - J. Cell. Sci. (2015)

Bottom Line: Cdk9 expression and activity were inhibited in the zebrafish (Danio rerio) embryo.We show that dephosphorylation of residue Ser2 on the C-terminal domain of RNA polymerase II is associated with impaired cardiac structure and function, and cardiomyocyte proliferation and also results in impaired functional recovery following cardiac laser injury.Larp7 knockdown rescued the structural and functional phenotype associated with knockdown of Cdk9.

View Article: PubMed Central - PubMed

Affiliation: British Heart Foundation Centre for Cardiovascular Science, The Queen's Medical Research Institute, The University of Edinburgh, Edinburgh EH16 4TJ, UK Center for Cardiovascular Regeneration, Department of Cardiovascular Sciences, Methodist Hospital Research Institute, Houston, TX 77030, USA.

No MeSH data available.


Related in: MedlinePlus

Effects of CDK9 inhibition or knockdown on the structure and function of the developing zebrafish heart. For pharmacological inhibition (A), embryos were continuously exposed to vehicle (1% DMSO, clear bars) or flavopiridol (3 μmol/l, dark bars) from 24 to 120 hpf. For morpholino-mediated knockdown (B), embryo eggs at the one- to two-cell stage were injected with Cdk9 mismatch morpholino (clear bars) or Cdk9-targeting morpholino (SB, black bars). Ventricle ejection fraction (A,B, upper panels) and diastolic area (A,B, lower panels) were assessed sequentially in the same embryos at 72, 96 and 120 hpf. Images in C show embryonic hearts following treatment with flavopiridol and Cdk9-Mo (SB). Left-hand panels are bright field images of the heart, and right-hand panels are histological sections through the heart stained with haematoxylin and eosin (H&E). n=3 experiments, >10 embryos per experiment, *P<0.05, **P<0.01, ***P<0.001. Two-way ANOVA test for repeated measures followed by Bonferroni's post-hoc test. ‘A’, atrium; BA, bulbous arteriosus; V, ventricle. Means±s.e.m. are shown in upper and lower panels of A and B.
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JCS175018F3: Effects of CDK9 inhibition or knockdown on the structure and function of the developing zebrafish heart. For pharmacological inhibition (A), embryos were continuously exposed to vehicle (1% DMSO, clear bars) or flavopiridol (3 μmol/l, dark bars) from 24 to 120 hpf. For morpholino-mediated knockdown (B), embryo eggs at the one- to two-cell stage were injected with Cdk9 mismatch morpholino (clear bars) or Cdk9-targeting morpholino (SB, black bars). Ventricle ejection fraction (A,B, upper panels) and diastolic area (A,B, lower panels) were assessed sequentially in the same embryos at 72, 96 and 120 hpf. Images in C show embryonic hearts following treatment with flavopiridol and Cdk9-Mo (SB). Left-hand panels are bright field images of the heart, and right-hand panels are histological sections through the heart stained with haematoxylin and eosin (H&E). n=3 experiments, >10 embryos per experiment, *P<0.05, **P<0.01, ***P<0.001. Two-way ANOVA test for repeated measures followed by Bonferroni's post-hoc test. ‘A’, atrium; BA, bulbous arteriosus; V, ventricle. Means±s.e.m. are shown in upper and lower panels of A and B.

Mentions: During normal development, zebrafish larvae show a progressive increase in ventricle size, measured as diastolic area, in the period 72–120 hpf. The ejection fraction of the ventricle does not change during normal development. However, the increase in heart rate and cardiac size results in an increase in cardiac output. Pharmacological inhibition of Cdk9 with flavopiridol from 24 hpf onwards reduced ventricle size and the ejection fraction compared to controls (Fig. 3A), although flavopiridol did not have a great impact on the anatomical structure of the heart (Fig. 3C). Treatment with Cdk9-Mo-SB had a marked effect on cardiac structure during development with a high proportion of hearts showing a string-like appearance at 120 hpf (Fig. 3B,C). These hearts were also significantly smaller and displayed a reduced ejection fraction (Fig. 3B).Fig. 3.


CDK9 and its repressor LARP7 modulate cardiomyocyte proliferation and response to injury in the zebrafish heart.

Matrone G, Wilson KS, Maqsood S, Mullins JJ, Tucker CS, Denvir MA - J. Cell. Sci. (2015)

Effects of CDK9 inhibition or knockdown on the structure and function of the developing zebrafish heart. For pharmacological inhibition (A), embryos were continuously exposed to vehicle (1% DMSO, clear bars) or flavopiridol (3 μmol/l, dark bars) from 24 to 120 hpf. For morpholino-mediated knockdown (B), embryo eggs at the one- to two-cell stage were injected with Cdk9 mismatch morpholino (clear bars) or Cdk9-targeting morpholino (SB, black bars). Ventricle ejection fraction (A,B, upper panels) and diastolic area (A,B, lower panels) were assessed sequentially in the same embryos at 72, 96 and 120 hpf. Images in C show embryonic hearts following treatment with flavopiridol and Cdk9-Mo (SB). Left-hand panels are bright field images of the heart, and right-hand panels are histological sections through the heart stained with haematoxylin and eosin (H&E). n=3 experiments, >10 embryos per experiment, *P<0.05, **P<0.01, ***P<0.001. Two-way ANOVA test for repeated measures followed by Bonferroni's post-hoc test. ‘A’, atrium; BA, bulbous arteriosus; V, ventricle. Means±s.e.m. are shown in upper and lower panels of A and B.
© Copyright Policy - open-access
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4696495&req=5

JCS175018F3: Effects of CDK9 inhibition or knockdown on the structure and function of the developing zebrafish heart. For pharmacological inhibition (A), embryos were continuously exposed to vehicle (1% DMSO, clear bars) or flavopiridol (3 μmol/l, dark bars) from 24 to 120 hpf. For morpholino-mediated knockdown (B), embryo eggs at the one- to two-cell stage were injected with Cdk9 mismatch morpholino (clear bars) or Cdk9-targeting morpholino (SB, black bars). Ventricle ejection fraction (A,B, upper panels) and diastolic area (A,B, lower panels) were assessed sequentially in the same embryos at 72, 96 and 120 hpf. Images in C show embryonic hearts following treatment with flavopiridol and Cdk9-Mo (SB). Left-hand panels are bright field images of the heart, and right-hand panels are histological sections through the heart stained with haematoxylin and eosin (H&E). n=3 experiments, >10 embryos per experiment, *P<0.05, **P<0.01, ***P<0.001. Two-way ANOVA test for repeated measures followed by Bonferroni's post-hoc test. ‘A’, atrium; BA, bulbous arteriosus; V, ventricle. Means±s.e.m. are shown in upper and lower panels of A and B.
Mentions: During normal development, zebrafish larvae show a progressive increase in ventricle size, measured as diastolic area, in the period 72–120 hpf. The ejection fraction of the ventricle does not change during normal development. However, the increase in heart rate and cardiac size results in an increase in cardiac output. Pharmacological inhibition of Cdk9 with flavopiridol from 24 hpf onwards reduced ventricle size and the ejection fraction compared to controls (Fig. 3A), although flavopiridol did not have a great impact on the anatomical structure of the heart (Fig. 3C). Treatment with Cdk9-Mo-SB had a marked effect on cardiac structure during development with a high proportion of hearts showing a string-like appearance at 120 hpf (Fig. 3B,C). These hearts were also significantly smaller and displayed a reduced ejection fraction (Fig. 3B).Fig. 3.

Bottom Line: Cdk9 expression and activity were inhibited in the zebrafish (Danio rerio) embryo.We show that dephosphorylation of residue Ser2 on the C-terminal domain of RNA polymerase II is associated with impaired cardiac structure and function, and cardiomyocyte proliferation and also results in impaired functional recovery following cardiac laser injury.Larp7 knockdown rescued the structural and functional phenotype associated with knockdown of Cdk9.

View Article: PubMed Central - PubMed

Affiliation: British Heart Foundation Centre for Cardiovascular Science, The Queen's Medical Research Institute, The University of Edinburgh, Edinburgh EH16 4TJ, UK Center for Cardiovascular Regeneration, Department of Cardiovascular Sciences, Methodist Hospital Research Institute, Houston, TX 77030, USA.

No MeSH data available.


Related in: MedlinePlus