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Profilin modulates sarcomeric organization and mediates cardiomyocyte hypertrophy.

Kooij V, Viswanathan MC, Lee DI, Rainer PP, Schmidt W, Kronert WA, Harding SE, Kass DA, Bernstein SI, Van Eyk JE, Cammarato A - Cardiovasc. Res. (2016)

Bottom Line: Mechanistically, we found that profilin-1 regulates hypertrophy, in part, through activation of the ERK1/2 signalling cascade.Elevated profilin levels resulted in elongated sarcomeres, myofibrillar disorganization, and sarcomeric disarray, which correlated with impaired muscle function.Our results identify novel roles for profilin as an important mediator of cardiomyocyte hypertrophy.

View Article: PubMed Central - PubMed

Affiliation: Department of Medicine, Division of Cardiology, The Johns Hopkins University, Baltimore, MD, USA National Heart and Lung Institute, Imperial College London, 4th floor, ICTEM, Hammersmith Campus, Du Cane Road, London W12 0NN, UK v.kooij@imperial.ac.uk.

No MeSH data available.


Related in: MedlinePlus

Profilin-1 is involved in the ERK1/2 signalling pathway. (A) The transcriptional activity of RCAN and MEF2 significantly increased when cells were stimulated with PE. Activity did not decrease upon silencing of profilin-1 (n = 5, **P < 0.01 and ***P < 0.001; two-way ANOVA with the Bonferroni post hoc test). (B) Phosphorylation levels of JNK (corrected for total JNK) and p38 (corrected for total p38) were unaltered by Pfn1 silencing and PE treatment (n = 3, two-way ANOVA with the Bonferroni post hoc test). (C) Phosphorylation of ERK1/2 (corrected for total ERK1/2) and Raf (corrected for GAPDH) was significantly increased in hypertrophic NRVMs and reduced upon diminished profilin-1 expression (n = 3, *P < 0.05 and **P < 0.01; two-way ANOVA with the Bonferroni post hoc test). (D) PE-increased mRNA levels of IL-6 and CTGF, effector genes of the ERK1/2 signalling cascade, were significantly reduced upon silencing of Pfn1 (n = 3, *P < 0.05, **P < 0.01, and ***P < 0.001; two-way ANOVA with the Bonferroni post hoc test).
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CVW050F7: Profilin-1 is involved in the ERK1/2 signalling pathway. (A) The transcriptional activity of RCAN and MEF2 significantly increased when cells were stimulated with PE. Activity did not decrease upon silencing of profilin-1 (n = 5, **P < 0.01 and ***P < 0.001; two-way ANOVA with the Bonferroni post hoc test). (B) Phosphorylation levels of JNK (corrected for total JNK) and p38 (corrected for total p38) were unaltered by Pfn1 silencing and PE treatment (n = 3, two-way ANOVA with the Bonferroni post hoc test). (C) Phosphorylation of ERK1/2 (corrected for total ERK1/2) and Raf (corrected for GAPDH) was significantly increased in hypertrophic NRVMs and reduced upon diminished profilin-1 expression (n = 3, *P < 0.05 and **P < 0.01; two-way ANOVA with the Bonferroni post hoc test). (D) PE-increased mRNA levels of IL-6 and CTGF, effector genes of the ERK1/2 signalling cascade, were significantly reduced upon silencing of Pfn1 (n = 3, *P < 0.05, **P < 0.01, and ***P < 0.001; two-way ANOVA with the Bonferroni post hoc test).

Mentions: To elucidate the signalling pathway involved in profilin-1-mediated cardiomyocyte-specific remodelling, we evaluated the activity of two major transcription factors (NFAT and MEF2) that govern the stress response during cardiac hypertrophy.37 Activity was measured using luciferase assays with the regulator of calcineurin (RCAN, an upstream regulator of NFAT) and MEF2 reporters. Following incubation with Pfn1 siRNA and PE, RCAN and MEF2 luciferase signals were not reduced (n = 5), suggesting the profilin-1-associated hypertrophic response relies on alternative signal transduction pathways (Figure 7A). Next, involvement of the mitogen-activated protein kinase (MAPK) hypertrophic signalling pathway was tested. The amount of phosphorylated JNK and p38 was not significantly different among the groups and thus did not appear to be involved (n = 3; Figure 7B). However, activated (phosphorylated active sites) levels of ERK1/2 (Thr 202/Tyr 204) and Raf (Ser 338) were significantly reduced in cells treated with PE and Pfn1 siRNA compared with control PE-treated cells, indicating that profilin-1 is likely involved in the ERK1/2 MAPK hypertrophic signalling pathway (n = 3; Figure 7C). Consistent with this result, we measured reduced transcript levels of two downstream genes, IL-6 and CTGF, of the ERK1/2 signalling pathway upon silencing of Pfn1 in cells stimulated with PE (Figure 7D) and ET1 (see Supplementary material online, Figure S4). Particular proteins, collagens, actin isoforms, and actin-binding proteins, however, remained unaltered following PE stimulation in cardiomyocytes with profilin-1 knockdown (see Supplementary material online, Figure S5A–C).Figure 7


Profilin modulates sarcomeric organization and mediates cardiomyocyte hypertrophy.

Kooij V, Viswanathan MC, Lee DI, Rainer PP, Schmidt W, Kronert WA, Harding SE, Kass DA, Bernstein SI, Van Eyk JE, Cammarato A - Cardiovasc. Res. (2016)

Profilin-1 is involved in the ERK1/2 signalling pathway. (A) The transcriptional activity of RCAN and MEF2 significantly increased when cells were stimulated with PE. Activity did not decrease upon silencing of profilin-1 (n = 5, **P < 0.01 and ***P < 0.001; two-way ANOVA with the Bonferroni post hoc test). (B) Phosphorylation levels of JNK (corrected for total JNK) and p38 (corrected for total p38) were unaltered by Pfn1 silencing and PE treatment (n = 3, two-way ANOVA with the Bonferroni post hoc test). (C) Phosphorylation of ERK1/2 (corrected for total ERK1/2) and Raf (corrected for GAPDH) was significantly increased in hypertrophic NRVMs and reduced upon diminished profilin-1 expression (n = 3, *P < 0.05 and **P < 0.01; two-way ANOVA with the Bonferroni post hoc test). (D) PE-increased mRNA levels of IL-6 and CTGF, effector genes of the ERK1/2 signalling cascade, were significantly reduced upon silencing of Pfn1 (n = 3, *P < 0.05, **P < 0.01, and ***P < 0.001; two-way ANOVA with the Bonferroni post hoc test).
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Related In: Results  -  Collection

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CVW050F7: Profilin-1 is involved in the ERK1/2 signalling pathway. (A) The transcriptional activity of RCAN and MEF2 significantly increased when cells were stimulated with PE. Activity did not decrease upon silencing of profilin-1 (n = 5, **P < 0.01 and ***P < 0.001; two-way ANOVA with the Bonferroni post hoc test). (B) Phosphorylation levels of JNK (corrected for total JNK) and p38 (corrected for total p38) were unaltered by Pfn1 silencing and PE treatment (n = 3, two-way ANOVA with the Bonferroni post hoc test). (C) Phosphorylation of ERK1/2 (corrected for total ERK1/2) and Raf (corrected for GAPDH) was significantly increased in hypertrophic NRVMs and reduced upon diminished profilin-1 expression (n = 3, *P < 0.05 and **P < 0.01; two-way ANOVA with the Bonferroni post hoc test). (D) PE-increased mRNA levels of IL-6 and CTGF, effector genes of the ERK1/2 signalling cascade, were significantly reduced upon silencing of Pfn1 (n = 3, *P < 0.05, **P < 0.01, and ***P < 0.001; two-way ANOVA with the Bonferroni post hoc test).
Mentions: To elucidate the signalling pathway involved in profilin-1-mediated cardiomyocyte-specific remodelling, we evaluated the activity of two major transcription factors (NFAT and MEF2) that govern the stress response during cardiac hypertrophy.37 Activity was measured using luciferase assays with the regulator of calcineurin (RCAN, an upstream regulator of NFAT) and MEF2 reporters. Following incubation with Pfn1 siRNA and PE, RCAN and MEF2 luciferase signals were not reduced (n = 5), suggesting the profilin-1-associated hypertrophic response relies on alternative signal transduction pathways (Figure 7A). Next, involvement of the mitogen-activated protein kinase (MAPK) hypertrophic signalling pathway was tested. The amount of phosphorylated JNK and p38 was not significantly different among the groups and thus did not appear to be involved (n = 3; Figure 7B). However, activated (phosphorylated active sites) levels of ERK1/2 (Thr 202/Tyr 204) and Raf (Ser 338) were significantly reduced in cells treated with PE and Pfn1 siRNA compared with control PE-treated cells, indicating that profilin-1 is likely involved in the ERK1/2 MAPK hypertrophic signalling pathway (n = 3; Figure 7C). Consistent with this result, we measured reduced transcript levels of two downstream genes, IL-6 and CTGF, of the ERK1/2 signalling pathway upon silencing of Pfn1 in cells stimulated with PE (Figure 7D) and ET1 (see Supplementary material online, Figure S4). Particular proteins, collagens, actin isoforms, and actin-binding proteins, however, remained unaltered following PE stimulation in cardiomyocytes with profilin-1 knockdown (see Supplementary material online, Figure S5A–C).Figure 7

Bottom Line: Mechanistically, we found that profilin-1 regulates hypertrophy, in part, through activation of the ERK1/2 signalling cascade.Elevated profilin levels resulted in elongated sarcomeres, myofibrillar disorganization, and sarcomeric disarray, which correlated with impaired muscle function.Our results identify novel roles for profilin as an important mediator of cardiomyocyte hypertrophy.

View Article: PubMed Central - PubMed

Affiliation: Department of Medicine, Division of Cardiology, The Johns Hopkins University, Baltimore, MD, USA National Heart and Lung Institute, Imperial College London, 4th floor, ICTEM, Hammersmith Campus, Du Cane Road, London W12 0NN, UK v.kooij@imperial.ac.uk.

No MeSH data available.


Related in: MedlinePlus