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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

Overexpression of profilin in Drosophila IFM impairs muscle function and ultrastructure. (A) Western blot analysis showed increased profilin in whole Mef2 > Pfn_1 and Mef2 > Pfn_2 transgenic flies (top) (n = 5, *P < 0.05, **P < 0.01; one-way ANOVA with the Bonferroni post hoc test). Actin/myosin heavy chain ratios remained unchanged in flies with muscle-restricted profilin overexpression compared with control (bottom) (n = 5). (B) Two-day-old Mef2 > Pfn_1 and Mef2 > Pfn_2 flies were unable to fly and demonstrated significantly reduced climbing ability (n = 35–64, ***P < 0.001; Kruskal–Wallis test with Dunn's post hoc test). (C) UH3-GAL4-mediated overexpression of profilin significantly diminished flight ability (n = 54–83, ***P < 0.001; one-way ANOVA with the Bonferroni post hoc test). (D) Representative electron micrographs of transverse sections of Mef2 > Pfn_1 IFMs (top) show that the double hexagonal lattice of myofilament arrangement was less ordered and thin and thick filaments were missing on the outer edges of the myofibril (inset) relative to control. Moreover, there was Z-band buckling and M-line distortion in longitudinal sections (bottom). Single arrowheads delineate an M-line and double arrowheads a Z-line. MT, mitochondrion; MF, myofibril. Scale bars, 500 nm and 250 nm for longitudinal and transverse sections, respectively, and 50 nm in the inset.
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CVW050F3: Overexpression of profilin in Drosophila IFM impairs muscle function and ultrastructure. (A) Western blot analysis showed increased profilin in whole Mef2 > Pfn_1 and Mef2 > Pfn_2 transgenic flies (top) (n = 5, *P < 0.05, **P < 0.01; one-way ANOVA with the Bonferroni post hoc test). Actin/myosin heavy chain ratios remained unchanged in flies with muscle-restricted profilin overexpression compared with control (bottom) (n = 5). (B) Two-day-old Mef2 > Pfn_1 and Mef2 > Pfn_2 flies were unable to fly and demonstrated significantly reduced climbing ability (n = 35–64, ***P < 0.001; Kruskal–Wallis test with Dunn's post hoc test). (C) UH3-GAL4-mediated overexpression of profilin significantly diminished flight ability (n = 54–83, ***P < 0.001; one-way ANOVA with the Bonferroni post hoc test). (D) Representative electron micrographs of transverse sections of Mef2 > Pfn_1 IFMs (top) show that the double hexagonal lattice of myofilament arrangement was less ordered and thin and thick filaments were missing on the outer edges of the myofibril (inset) relative to control. Moreover, there was Z-band buckling and M-line distortion in longitudinal sections (bottom). Single arrowheads delineate an M-line and double arrowheads a Z-line. MT, mitochondrion; MF, myofibril. Scale bars, 500 nm and 250 nm for longitudinal and transverse sections, respectively, and 50 nm in the inset.

Mentions: To further index myopathic effects associated with elevated profilin levels, transgenic Drosophila overexpressing Pfn_1 and Pfn_2 throughout the somatic musculature were established using the Mef2-GAL4 driver line. Mef2 > Pfn_1 flies (n = 5) exhibited a significant, ∼17-fold increase of profilin, whereas Mef2 > Pfn_2 flies (n = 5) showed an ∼8-fold increase compared with controls (Figure 3A). Actin/myosin heavy chain (MHC) ratio and individual intensity values normalized to total intensity, determined by densitometric analysis of Coomassie-stained protein bands, were not altered in these flies (Figure 3A and see Supplementary material online, Figure S2). Muscle performance was evaluated in 2-day-old flies using flight and climbing assays. Elevated profilin eliminated flight and reduced climbing abilities (control 14.91 ± 0.50 cm, n = 64; Mef2 > Pfn_1 9.29 ± 0.56 cm, n = 48; Mef2 > Pfn_2 9.43 ± 0.58 cm, n = 35; Figure 3B). Furthermore, IFM-specific overexpression of profilin via UH3-GAL427 reduced, but did not completely abolish flight ability compared with control animals (control 5.11 ± 0.17 a.u., n = 83; UH3 > Pfn_1 1.43 ± 0.19 a.u., n = 74; UH3 > Pfn_2 2.30 ± 0.39 a.u., n = 54; Figure 3C).Figure 3


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)

Overexpression of profilin in Drosophila IFM impairs muscle function and ultrastructure. (A) Western blot analysis showed increased profilin in whole Mef2 > Pfn_1 and Mef2 > Pfn_2 transgenic flies (top) (n = 5, *P < 0.05, **P < 0.01; one-way ANOVA with the Bonferroni post hoc test). Actin/myosin heavy chain ratios remained unchanged in flies with muscle-restricted profilin overexpression compared with control (bottom) (n = 5). (B) Two-day-old Mef2 > Pfn_1 and Mef2 > Pfn_2 flies were unable to fly and demonstrated significantly reduced climbing ability (n = 35–64, ***P < 0.001; Kruskal–Wallis test with Dunn's post hoc test). (C) UH3-GAL4-mediated overexpression of profilin significantly diminished flight ability (n = 54–83, ***P < 0.001; one-way ANOVA with the Bonferroni post hoc test). (D) Representative electron micrographs of transverse sections of Mef2 > Pfn_1 IFMs (top) show that the double hexagonal lattice of myofilament arrangement was less ordered and thin and thick filaments were missing on the outer edges of the myofibril (inset) relative to control. Moreover, there was Z-band buckling and M-line distortion in longitudinal sections (bottom). Single arrowheads delineate an M-line and double arrowheads a Z-line. MT, mitochondrion; MF, myofibril. Scale bars, 500 nm and 250 nm for longitudinal and transverse sections, respectively, and 50 nm in the inset.
© Copyright Policy - creative-commons
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4836629&req=5

CVW050F3: Overexpression of profilin in Drosophila IFM impairs muscle function and ultrastructure. (A) Western blot analysis showed increased profilin in whole Mef2 > Pfn_1 and Mef2 > Pfn_2 transgenic flies (top) (n = 5, *P < 0.05, **P < 0.01; one-way ANOVA with the Bonferroni post hoc test). Actin/myosin heavy chain ratios remained unchanged in flies with muscle-restricted profilin overexpression compared with control (bottom) (n = 5). (B) Two-day-old Mef2 > Pfn_1 and Mef2 > Pfn_2 flies were unable to fly and demonstrated significantly reduced climbing ability (n = 35–64, ***P < 0.001; Kruskal–Wallis test with Dunn's post hoc test). (C) UH3-GAL4-mediated overexpression of profilin significantly diminished flight ability (n = 54–83, ***P < 0.001; one-way ANOVA with the Bonferroni post hoc test). (D) Representative electron micrographs of transverse sections of Mef2 > Pfn_1 IFMs (top) show that the double hexagonal lattice of myofilament arrangement was less ordered and thin and thick filaments were missing on the outer edges of the myofibril (inset) relative to control. Moreover, there was Z-band buckling and M-line distortion in longitudinal sections (bottom). Single arrowheads delineate an M-line and double arrowheads a Z-line. MT, mitochondrion; MF, myofibril. Scale bars, 500 nm and 250 nm for longitudinal and transverse sections, respectively, and 50 nm in the inset.
Mentions: To further index myopathic effects associated with elevated profilin levels, transgenic Drosophila overexpressing Pfn_1 and Pfn_2 throughout the somatic musculature were established using the Mef2-GAL4 driver line. Mef2 > Pfn_1 flies (n = 5) exhibited a significant, ∼17-fold increase of profilin, whereas Mef2 > Pfn_2 flies (n = 5) showed an ∼8-fold increase compared with controls (Figure 3A). Actin/myosin heavy chain (MHC) ratio and individual intensity values normalized to total intensity, determined by densitometric analysis of Coomassie-stained protein bands, were not altered in these flies (Figure 3A and see Supplementary material online, Figure S2). Muscle performance was evaluated in 2-day-old flies using flight and climbing assays. Elevated profilin eliminated flight and reduced climbing abilities (control 14.91 ± 0.50 cm, n = 64; Mef2 > Pfn_1 9.29 ± 0.56 cm, n = 48; Mef2 > Pfn_2 9.43 ± 0.58 cm, n = 35; Figure 3B). Furthermore, IFM-specific overexpression of profilin via UH3-GAL427 reduced, but did not completely abolish flight ability compared with control animals (control 5.11 ± 0.17 a.u., n = 83; UH3 > Pfn_1 1.43 ± 0.19 a.u., n = 74; UH3 > Pfn_2 2.30 ± 0.39 a.u., n = 54; Figure 3C).Figure 3

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