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The Early-Onset Myocardial Infarction Associated PHACTR1 Gene Regulates Skeletal and Cardiac Alpha-Actin Gene Expression.

Kelloniemi A, Szabo Z, Serpi R, Näpänkangas J, Ohukainen P, Tenhunen O, Kaikkonen L, Koivisto E, Bagyura Z, Kerkelä R, Leosdottir M, Hedner T, Melander O, Ruskoaho H, Rysä J - PLoS ONE (2015)

Bottom Line: We characterized the mechanisms regulating Phactr1 expression in the heart, used adenoviral gene delivery to investigate the effects of Phactr1 on cardiac function, and analyzed the relationship between MI associated PHACTR1 allele and cardiac function in human subjects.When the direct myocardial effects of Phactr1 were studied, the skeletal α-actin to cardiac α-actin isoform ratio was significantly higher (1.5-fold, P<0.05) at 3 days but 40% lower (P<0.05) at 2 weeks after adenovirus-mediated Phactr1 gene delivery into the anterior wall of the left ventricle.In human subjects, MI associated PHACTR1 allele was not associated significantly with cardiac function (n = 1550).

View Article: PubMed Central - PubMed

Affiliation: Institute of Biomedicine, Department of Pharmacology and Toxicology, University of Oulu, Oulu, Finland.

ABSTRACT
The phosphatase and actin regulator 1 (PHACTR1) locus is a very commonly identified hit in genome-wide association studies investigating coronary artery disease and myocardial infarction (MI). However, the function of PHACTR1 in the heart is still unknown. We characterized the mechanisms regulating Phactr1 expression in the heart, used adenoviral gene delivery to investigate the effects of Phactr1 on cardiac function, and analyzed the relationship between MI associated PHACTR1 allele and cardiac function in human subjects. Phactr1 mRNA and protein levels were markedly reduced (60%, P<0.01 and 90%, P<0.001, respectively) at 1 day after MI in rats. When the direct myocardial effects of Phactr1 were studied, the skeletal α-actin to cardiac α-actin isoform ratio was significantly higher (1.5-fold, P<0.05) at 3 days but 40% lower (P<0.05) at 2 weeks after adenovirus-mediated Phactr1 gene delivery into the anterior wall of the left ventricle. Similarly, the skeletal α-actin to cardiac α-actin ratio was lower at 2 weeks in infarcted hearts overexpressing Phactr1. In cultured neonatal cardiac myocytes, adenovirus-mediated Phactr1 overexpression for 48 hours markedly increased the skeletal α-actin to cardiac α-actin ratio, this being associated with an enhanced DNA binding activity of serum response factor. Phactr1 overexpression exerted no major effects on the expression of other cardiac genes or LV structure and function in normal and infarcted hearts during 2 weeks' follow-up period. In human subjects, MI associated PHACTR1 allele was not associated significantly with cardiac function (n = 1550). Phactr1 seems to regulate the skeletal to cardiac α-actin isoform ratio.

No MeSH data available.


Related in: MedlinePlus

Effects of Phactr1 overexpression in cultured ventricular myocytes.A) Phactr1 mRNA levels measured by RT-PCR from cultured neonatal rat ventricular myocytes (NRVMs) transduced with Phactr1 or LacZ adenovirus for 48 hours at the virus amount of 1MOI, 2 MOI and 4 MOI. B) Skeletal α-actin (skα-A) and cardiac α-actin (caα-A) mRNA levels and skα-A to caα-A ratio, and C) β-myosin heavy chain (β-MHC) and α-myosin heavy chain (α-MHC) mRNA levels and β-MHC to α-MHC ratio from cultured NRVMs transduced with Phactr1 or LacZ adenovirus at the virus concentration of 4 MOI. Open bars represent LacZ and solid bars Phactr1 (n = 11–12 from 3 different experiments) *P<0.05, **P<0.01, ***P<0.001 versus LacZ (Student’s t-test). D) SRF DNA binding activity in cultured NRVMs transduced with Phactr1 adenovirus at the virus concentration of 1 MOI. Open bars represent LacZ and solid bars Phactr1 (n = 7–9). *P< 0.05 versus LacZ (Student’s t-test). E) ANP, α-SMA, c-fos, corin, BMP2 and GATA4 mRNA levels measured by RT-PCR from cultured NRVMs transduced with Phactr1 or LacZ adenovirus for 48 hours at the virus concentration of 4 MOI. Open bars represent LacZ and solid bars Phactr1 (n = 11–12 from 3 different experiments) ***P<0.001 versus LacZ (Student’s t-test). The results are expressed as mean±SEM.
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pone.0130502.g009: Effects of Phactr1 overexpression in cultured ventricular myocytes.A) Phactr1 mRNA levels measured by RT-PCR from cultured neonatal rat ventricular myocytes (NRVMs) transduced with Phactr1 or LacZ adenovirus for 48 hours at the virus amount of 1MOI, 2 MOI and 4 MOI. B) Skeletal α-actin (skα-A) and cardiac α-actin (caα-A) mRNA levels and skα-A to caα-A ratio, and C) β-myosin heavy chain (β-MHC) and α-myosin heavy chain (α-MHC) mRNA levels and β-MHC to α-MHC ratio from cultured NRVMs transduced with Phactr1 or LacZ adenovirus at the virus concentration of 4 MOI. Open bars represent LacZ and solid bars Phactr1 (n = 11–12 from 3 different experiments) *P<0.05, **P<0.01, ***P<0.001 versus LacZ (Student’s t-test). D) SRF DNA binding activity in cultured NRVMs transduced with Phactr1 adenovirus at the virus concentration of 1 MOI. Open bars represent LacZ and solid bars Phactr1 (n = 7–9). *P< 0.05 versus LacZ (Student’s t-test). E) ANP, α-SMA, c-fos, corin, BMP2 and GATA4 mRNA levels measured by RT-PCR from cultured NRVMs transduced with Phactr1 or LacZ adenovirus for 48 hours at the virus concentration of 4 MOI. Open bars represent LacZ and solid bars Phactr1 (n = 11–12 from 3 different experiments) ***P<0.001 versus LacZ (Student’s t-test). The results are expressed as mean±SEM.

Mentions: To further evaluate the role of Phactr1 in regulating cardiac gene expression, we transfected cultured NRVMs with recombinant adenoviruses at the virus concentration of 1, 2 or 4 MOI. Phactr1 mRNA levels were elevated dose-dependently and were significantly increased already at the virus concentration of 1 MOI (Fig 9A). In agreement with in vivo studies at 3 days, the skeletal α-actin to cardiac α-actin ratio significantly increased in response to adenovirus-mediated Phactr1 overexpression for 48 hours used at the concentration of 4 MOI, to ensure that Phactr1 had been fully overexpressed (Fig 9B). In addition, the β-myosin heavy chain to α-myosin heavy chain ratio increased significantly in NRVMs (Fig 9C).


The Early-Onset Myocardial Infarction Associated PHACTR1 Gene Regulates Skeletal and Cardiac Alpha-Actin Gene Expression.

Kelloniemi A, Szabo Z, Serpi R, Näpänkangas J, Ohukainen P, Tenhunen O, Kaikkonen L, Koivisto E, Bagyura Z, Kerkelä R, Leosdottir M, Hedner T, Melander O, Ruskoaho H, Rysä J - PLoS ONE (2015)

Effects of Phactr1 overexpression in cultured ventricular myocytes.A) Phactr1 mRNA levels measured by RT-PCR from cultured neonatal rat ventricular myocytes (NRVMs) transduced with Phactr1 or LacZ adenovirus for 48 hours at the virus amount of 1MOI, 2 MOI and 4 MOI. B) Skeletal α-actin (skα-A) and cardiac α-actin (caα-A) mRNA levels and skα-A to caα-A ratio, and C) β-myosin heavy chain (β-MHC) and α-myosin heavy chain (α-MHC) mRNA levels and β-MHC to α-MHC ratio from cultured NRVMs transduced with Phactr1 or LacZ adenovirus at the virus concentration of 4 MOI. Open bars represent LacZ and solid bars Phactr1 (n = 11–12 from 3 different experiments) *P<0.05, **P<0.01, ***P<0.001 versus LacZ (Student’s t-test). D) SRF DNA binding activity in cultured NRVMs transduced with Phactr1 adenovirus at the virus concentration of 1 MOI. Open bars represent LacZ and solid bars Phactr1 (n = 7–9). *P< 0.05 versus LacZ (Student’s t-test). E) ANP, α-SMA, c-fos, corin, BMP2 and GATA4 mRNA levels measured by RT-PCR from cultured NRVMs transduced with Phactr1 or LacZ adenovirus for 48 hours at the virus concentration of 4 MOI. Open bars represent LacZ and solid bars Phactr1 (n = 11–12 from 3 different experiments) ***P<0.001 versus LacZ (Student’s t-test). The results are expressed as mean±SEM.
© Copyright Policy
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4476650&req=5

pone.0130502.g009: Effects of Phactr1 overexpression in cultured ventricular myocytes.A) Phactr1 mRNA levels measured by RT-PCR from cultured neonatal rat ventricular myocytes (NRVMs) transduced with Phactr1 or LacZ adenovirus for 48 hours at the virus amount of 1MOI, 2 MOI and 4 MOI. B) Skeletal α-actin (skα-A) and cardiac α-actin (caα-A) mRNA levels and skα-A to caα-A ratio, and C) β-myosin heavy chain (β-MHC) and α-myosin heavy chain (α-MHC) mRNA levels and β-MHC to α-MHC ratio from cultured NRVMs transduced with Phactr1 or LacZ adenovirus at the virus concentration of 4 MOI. Open bars represent LacZ and solid bars Phactr1 (n = 11–12 from 3 different experiments) *P<0.05, **P<0.01, ***P<0.001 versus LacZ (Student’s t-test). D) SRF DNA binding activity in cultured NRVMs transduced with Phactr1 adenovirus at the virus concentration of 1 MOI. Open bars represent LacZ and solid bars Phactr1 (n = 7–9). *P< 0.05 versus LacZ (Student’s t-test). E) ANP, α-SMA, c-fos, corin, BMP2 and GATA4 mRNA levels measured by RT-PCR from cultured NRVMs transduced with Phactr1 or LacZ adenovirus for 48 hours at the virus concentration of 4 MOI. Open bars represent LacZ and solid bars Phactr1 (n = 11–12 from 3 different experiments) ***P<0.001 versus LacZ (Student’s t-test). The results are expressed as mean±SEM.
Mentions: To further evaluate the role of Phactr1 in regulating cardiac gene expression, we transfected cultured NRVMs with recombinant adenoviruses at the virus concentration of 1, 2 or 4 MOI. Phactr1 mRNA levels were elevated dose-dependently and were significantly increased already at the virus concentration of 1 MOI (Fig 9A). In agreement with in vivo studies at 3 days, the skeletal α-actin to cardiac α-actin ratio significantly increased in response to adenovirus-mediated Phactr1 overexpression for 48 hours used at the concentration of 4 MOI, to ensure that Phactr1 had been fully overexpressed (Fig 9B). In addition, the β-myosin heavy chain to α-myosin heavy chain ratio increased significantly in NRVMs (Fig 9C).

Bottom Line: We characterized the mechanisms regulating Phactr1 expression in the heart, used adenoviral gene delivery to investigate the effects of Phactr1 on cardiac function, and analyzed the relationship between MI associated PHACTR1 allele and cardiac function in human subjects.When the direct myocardial effects of Phactr1 were studied, the skeletal α-actin to cardiac α-actin isoform ratio was significantly higher (1.5-fold, P<0.05) at 3 days but 40% lower (P<0.05) at 2 weeks after adenovirus-mediated Phactr1 gene delivery into the anterior wall of the left ventricle.In human subjects, MI associated PHACTR1 allele was not associated significantly with cardiac function (n = 1550).

View Article: PubMed Central - PubMed

Affiliation: Institute of Biomedicine, Department of Pharmacology and Toxicology, University of Oulu, Oulu, Finland.

ABSTRACT
The phosphatase and actin regulator 1 (PHACTR1) locus is a very commonly identified hit in genome-wide association studies investigating coronary artery disease and myocardial infarction (MI). However, the function of PHACTR1 in the heart is still unknown. We characterized the mechanisms regulating Phactr1 expression in the heart, used adenoviral gene delivery to investigate the effects of Phactr1 on cardiac function, and analyzed the relationship between MI associated PHACTR1 allele and cardiac function in human subjects. Phactr1 mRNA and protein levels were markedly reduced (60%, P<0.01 and 90%, P<0.001, respectively) at 1 day after MI in rats. When the direct myocardial effects of Phactr1 were studied, the skeletal α-actin to cardiac α-actin isoform ratio was significantly higher (1.5-fold, P<0.05) at 3 days but 40% lower (P<0.05) at 2 weeks after adenovirus-mediated Phactr1 gene delivery into the anterior wall of the left ventricle. Similarly, the skeletal α-actin to cardiac α-actin ratio was lower at 2 weeks in infarcted hearts overexpressing Phactr1. In cultured neonatal cardiac myocytes, adenovirus-mediated Phactr1 overexpression for 48 hours markedly increased the skeletal α-actin to cardiac α-actin ratio, this being associated with an enhanced DNA binding activity of serum response factor. Phactr1 overexpression exerted no major effects on the expression of other cardiac genes or LV structure and function in normal and infarcted hearts during 2 weeks' follow-up period. In human subjects, MI associated PHACTR1 allele was not associated significantly with cardiac function (n = 1550). Phactr1 seems to regulate the skeletal to cardiac α-actin isoform ratio.

No MeSH data available.


Related in: MedlinePlus