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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

Increased expression of profilin-1 in hypertrophic cardiomyocytes. (A) Pressure-overload following TAC resulted in elevated levels of profilin-1 in mouse hearts. Protein levels were corrected for total gel loading (see Supplementary material online, Figure S1A). Representative actin bands from Direct Blue 71-stained membranes are shown. A significant increase in profilin-1/total protein was observed in the myocardium of the TAC vs. Sham group (n = 5–10, *P < 0.05; Student's t-test). (B) A hypertrophic/HF mouse model overexpressing wild-type Gαq showed higher levels of cardiac profilin-1 compared with control (n = 3–7, *P < 0.05; Student's t-test). Protein levels were corrected for total gel loading (see Supplementary material online, Figure S1A). Representative actin bands from Direct Blue 71-stained membranes are shown. (C) PE treatment in NRVMs increased Pfn1 mRNA (n = 6, *P < 0.05; Student's t-test) and profilin-1 (n = 6, ***P < 0.001; Student's t-test) content. (D) Representative confocal images of control murine cardiac tissue show profilin-1 repetitively associates with myofibrils in a striated manner. Scale bar, 10 μm.
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CVW050F1: Increased expression of profilin-1 in hypertrophic cardiomyocytes. (A) Pressure-overload following TAC resulted in elevated levels of profilin-1 in mouse hearts. Protein levels were corrected for total gel loading (see Supplementary material online, Figure S1A). Representative actin bands from Direct Blue 71-stained membranes are shown. A significant increase in profilin-1/total protein was observed in the myocardium of the TAC vs. Sham group (n = 5–10, *P < 0.05; Student's t-test). (B) A hypertrophic/HF mouse model overexpressing wild-type Gαq showed higher levels of cardiac profilin-1 compared with control (n = 3–7, *P < 0.05; Student's t-test). Protein levels were corrected for total gel loading (see Supplementary material online, Figure S1A). Representative actin bands from Direct Blue 71-stained membranes are shown. (C) PE treatment in NRVMs increased Pfn1 mRNA (n = 6, *P < 0.05; Student's t-test) and profilin-1 (n = 6, ***P < 0.001; Student's t-test) content. (D) Representative confocal images of control murine cardiac tissue show profilin-1 repetitively associates with myofibrils in a striated manner. Scale bar, 10 μm.

Mentions: To determine whether profilin-1 abundance in the heart is altered in different animal models of cardiac hypertrophy and HF, western blot analysis was performed on ventricular tissues from mice that underwent TAC (Figure 1A and see Supplementary material online, Figure S1A)35 and from Gαq-overexpressing mice and appropriate controls (Figure 1B and see Supplementary material online, Figure S1A).25 Relative to total protein, profilin-1 levels were ∼2.5-fold higher in the TAC group (0.40 ± 0.06 a.u., n = 10) compared with the control group (0.16 ± 0.04 a.u., n = 5). TAC animals additionally demonstrated cardiac dysfunction (see Supplementary material online, Figure S1B). Moreover, cardiac tissue obtained from Gαq-overexpressing mice showed significantly increased levels of profilin-1 (0.35 ± 0.02 a.u., n = 7) compared with controls (0.27 ± 0.02 a.u., n = 3). NRVMs were isolated to assess cardiomyocyte-specific expression levels of Pfn1 (profilin-1) in cells treated with PE or ET1 to stimulate hypertrophy. Pfn1 transcripts were significantly increased after stimulation with 20 μM PE for 24 h (1.7 ± 0.22, n = 6) compared with unstimulated NRVMs (1.0 ± 0.05, n = 6; Figure 1C), and also in NRVMs treated with 100 nM ET1 (1.3 ± 0.12, n = 6) relative to controls (1.0 ± 0.08, n = 6; see Supplementary material online, Figure S1C). Furthermore, profilin-1 was significantly more abundant after PE treatment (2.0 ± 0.08, n = 6) compared with untreated controls (1.1 ± 0.08, n = 6). To define the gross localization of profilin-1, sectioned cardiac tissue from control mice was subjected to anti-profilin-1 antibody, DAPI, and TRITC-phalloidin staining. Confocal images showed a striated profilin-1 signal, which implies the protein associates recurrently along sarcomeres (Figure 1D). This is consistent with earlier results,6 confirming the presence of profilin-1 in cardiomyocytes, and repetitive occupancy of profilin-1 along myofibrils. Cardiac tissues from explanted hearts of patients with end-stage HF (Failing) contained decreased PFN1 transcript levels (0.55 ± 0.04 a.u. n = 9) compared with donor hearts (Healthy, 1.05 ± 0.21 a.u., n = 8; see Supplementary material online, Table S1 and Figure S1D). The discrepancy in profilin-1/Pfn-1/PFN1 levels between the hypertrophic hearts and human end-stage failing hearts may be due to differences in disease and diseased (e.g. compensated vs. decompensated) state.Figure 1


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)

Increased expression of profilin-1 in hypertrophic cardiomyocytes. (A) Pressure-overload following TAC resulted in elevated levels of profilin-1 in mouse hearts. Protein levels were corrected for total gel loading (see Supplementary material online, Figure S1A). Representative actin bands from Direct Blue 71-stained membranes are shown. A significant increase in profilin-1/total protein was observed in the myocardium of the TAC vs. Sham group (n = 5–10, *P < 0.05; Student's t-test). (B) A hypertrophic/HF mouse model overexpressing wild-type Gαq showed higher levels of cardiac profilin-1 compared with control (n = 3–7, *P < 0.05; Student's t-test). Protein levels were corrected for total gel loading (see Supplementary material online, Figure S1A). Representative actin bands from Direct Blue 71-stained membranes are shown. (C) PE treatment in NRVMs increased Pfn1 mRNA (n = 6, *P < 0.05; Student's t-test) and profilin-1 (n = 6, ***P < 0.001; Student's t-test) content. (D) Representative confocal images of control murine cardiac tissue show profilin-1 repetitively associates with myofibrils in a striated manner. Scale bar, 10 μm.
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CVW050F1: Increased expression of profilin-1 in hypertrophic cardiomyocytes. (A) Pressure-overload following TAC resulted in elevated levels of profilin-1 in mouse hearts. Protein levels were corrected for total gel loading (see Supplementary material online, Figure S1A). Representative actin bands from Direct Blue 71-stained membranes are shown. A significant increase in profilin-1/total protein was observed in the myocardium of the TAC vs. Sham group (n = 5–10, *P < 0.05; Student's t-test). (B) A hypertrophic/HF mouse model overexpressing wild-type Gαq showed higher levels of cardiac profilin-1 compared with control (n = 3–7, *P < 0.05; Student's t-test). Protein levels were corrected for total gel loading (see Supplementary material online, Figure S1A). Representative actin bands from Direct Blue 71-stained membranes are shown. (C) PE treatment in NRVMs increased Pfn1 mRNA (n = 6, *P < 0.05; Student's t-test) and profilin-1 (n = 6, ***P < 0.001; Student's t-test) content. (D) Representative confocal images of control murine cardiac tissue show profilin-1 repetitively associates with myofibrils in a striated manner. Scale bar, 10 μm.
Mentions: To determine whether profilin-1 abundance in the heart is altered in different animal models of cardiac hypertrophy and HF, western blot analysis was performed on ventricular tissues from mice that underwent TAC (Figure 1A and see Supplementary material online, Figure S1A)35 and from Gαq-overexpressing mice and appropriate controls (Figure 1B and see Supplementary material online, Figure S1A).25 Relative to total protein, profilin-1 levels were ∼2.5-fold higher in the TAC group (0.40 ± 0.06 a.u., n = 10) compared with the control group (0.16 ± 0.04 a.u., n = 5). TAC animals additionally demonstrated cardiac dysfunction (see Supplementary material online, Figure S1B). Moreover, cardiac tissue obtained from Gαq-overexpressing mice showed significantly increased levels of profilin-1 (0.35 ± 0.02 a.u., n = 7) compared with controls (0.27 ± 0.02 a.u., n = 3). NRVMs were isolated to assess cardiomyocyte-specific expression levels of Pfn1 (profilin-1) in cells treated with PE or ET1 to stimulate hypertrophy. Pfn1 transcripts were significantly increased after stimulation with 20 μM PE for 24 h (1.7 ± 0.22, n = 6) compared with unstimulated NRVMs (1.0 ± 0.05, n = 6; Figure 1C), and also in NRVMs treated with 100 nM ET1 (1.3 ± 0.12, n = 6) relative to controls (1.0 ± 0.08, n = 6; see Supplementary material online, Figure S1C). Furthermore, profilin-1 was significantly more abundant after PE treatment (2.0 ± 0.08, n = 6) compared with untreated controls (1.1 ± 0.08, n = 6). To define the gross localization of profilin-1, sectioned cardiac tissue from control mice was subjected to anti-profilin-1 antibody, DAPI, and TRITC-phalloidin staining. Confocal images showed a striated profilin-1 signal, which implies the protein associates recurrently along sarcomeres (Figure 1D). This is consistent with earlier results,6 confirming the presence of profilin-1 in cardiomyocytes, and repetitive occupancy of profilin-1 along myofibrils. Cardiac tissues from explanted hearts of patients with end-stage HF (Failing) contained decreased PFN1 transcript levels (0.55 ± 0.04 a.u. n = 9) compared with donor hearts (Healthy, 1.05 ± 0.21 a.u., n = 8; see Supplementary material online, Table S1 and Figure S1D). The discrepancy in profilin-1/Pfn-1/PFN1 levels between the hypertrophic hearts and human end-stage failing hearts may be due to differences in disease and diseased (e.g. compensated vs. decompensated) state.Figure 1

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