Limits...
Re-expression of alpha skeletal actin as a marker for dedifferentiation in cardiac pathologies.

Driesen RB, Verheyen FK, Debie W, Blaauw E, Babiker FA, Cornelussen RN, Ausma J, Lenders MH, Borgers M, Chaponnier C, Ramaekers FC - J. Cell. Mol. Med. (2009)

Bottom Line: Differentiation of foetal cardiomyocytes is accompanied by sequential actin isoform expression, i.e. down-regulation of the 'embryonic' alpha smooth muscle actin, followed by an up-regulation of alpha skeletal actin (alphaSKA) and a final predominant expression of alpha cardiac actin (alphaCA).Immunohistochemistry of alphaCA, alphaSKA and cardiotin was performed on left ventricle biopsies from human patients after coronary bypass surgery.Dedifferentiating cardiomyocytes in vitro revealed a degradation of the contractile apparatus and local re-expression of alphaSKA.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular Cell Biology, Maastricht University, Maastricht, The Netherlands.

ABSTRACT
Differentiation of foetal cardiomyocytes is accompanied by sequential actin isoform expression, i.e. down-regulation of the 'embryonic' alpha smooth muscle actin, followed by an up-regulation of alpha skeletal actin (alphaSKA) and a final predominant expression of alpha cardiac actin (alphaCA). Our objective was to detect whether re-expression of alphaSKA occurred during cardiomyocyte dedifferentiation, a phenomenon that has been observed in different pathologies characterized by myocardial dysfunction. Immunohistochemistry of alphaCA, alphaSKA and cardiotin was performed on left ventricle biopsies from human patients after coronary bypass surgery. Furthermore, actin isoform expression was investigated in left ventricle samples of rabbit hearts suffering from pressure- and volume-overload and in adult rabbit ventricular cardiomyocytes during dedifferentiation in vitro. Atrial goat samples up to 16 weeks of sustained atrial fibrillation (AF) were studied ultrastructurally and were immunostained for alphaCA and alphaSKA. Up-regulation of alphaSKA was observed in human ventricular cardiomyocytes showing down-regulation of alphaCA and cardiotin. A patchy re-expression pattern of alphaSKA was observed in rabbit left ventricular tissue subjected to pressure- and volume-overload. Dedifferentiating cardiomyocytes in vitro revealed a degradation of the contractile apparatus and local re-expression of alphaSKA. Comparable alphaSKA staining patterns were found in several areas of atrial goat tissue during 16 weeks of AF together with a progressive glycogen accumulation at the same time intervals. The expression of alphaSKA in adult dedifferentiating cardiomyocytes, in combination with PAS-positive glycogen and decreased cardiotin expression, offers an additional tool in the evaluation of myocardial dysfunction and indicates major changes in the contractile properties of these cells.

Show MeSH

Related in: MedlinePlus

Detection of αCA (A, B), αSKA (C, D) and periodic acid Schiff (PAS) staining (E, F) in frozen sections from sham left rabbit ventricular myocardium (A, C, E) and left ventricular tissue after induction of 2 weeks aortic insuffiency and subsequently 16 weeks of banding (B, D, F). Re-expression of αSKA and presence of glycogen accumulation in the same areas of pressure and volume overloaded myocardium is evident. Scale bars represent 20 μm.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC3823406&req=5

fig03: Detection of αCA (A, B), αSKA (C, D) and periodic acid Schiff (PAS) staining (E, F) in frozen sections from sham left rabbit ventricular myocardium (A, C, E) and left ventricular tissue after induction of 2 weeks aortic insuffiency and subsequently 16 weeks of banding (B, D, F). Re-expression of αSKA and presence of glycogen accumulation in the same areas of pressure and volume overloaded myocardium is evident. Scale bars represent 20 μm.

Mentions: Longitudinal sections of left ventricle tissue of sham-operated rabbits revealed a normal αCA cross-striated pattern in the cardiomyocytes (Fig. 3A). The tissue was devoid of any αSKA expression (Fig. 3C) and the PAS staining showed no glycogen deposition (Fig. 3E). After 16 weeks of overload, αCA was still abundantly expressed (Fig. 3B) but some regions demonstrated an intense patchy expression of αSKA (between 20% and 40% of total tissue area) (Fig. 3D). PAS staining of the αSKA-positive regions often showed an accumulation of glycogen (Fig. 3F), although not all areas with αSKA-positive cardiomyocytes were PAS-positive.


Re-expression of alpha skeletal actin as a marker for dedifferentiation in cardiac pathologies.

Driesen RB, Verheyen FK, Debie W, Blaauw E, Babiker FA, Cornelussen RN, Ausma J, Lenders MH, Borgers M, Chaponnier C, Ramaekers FC - J. Cell. Mol. Med. (2009)

Detection of αCA (A, B), αSKA (C, D) and periodic acid Schiff (PAS) staining (E, F) in frozen sections from sham left rabbit ventricular myocardium (A, C, E) and left ventricular tissue after induction of 2 weeks aortic insuffiency and subsequently 16 weeks of banding (B, D, F). Re-expression of αSKA and presence of glycogen accumulation in the same areas of pressure and volume overloaded myocardium is evident. Scale bars represent 20 μm.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3823406&req=5

fig03: Detection of αCA (A, B), αSKA (C, D) and periodic acid Schiff (PAS) staining (E, F) in frozen sections from sham left rabbit ventricular myocardium (A, C, E) and left ventricular tissue after induction of 2 weeks aortic insuffiency and subsequently 16 weeks of banding (B, D, F). Re-expression of αSKA and presence of glycogen accumulation in the same areas of pressure and volume overloaded myocardium is evident. Scale bars represent 20 μm.
Mentions: Longitudinal sections of left ventricle tissue of sham-operated rabbits revealed a normal αCA cross-striated pattern in the cardiomyocytes (Fig. 3A). The tissue was devoid of any αSKA expression (Fig. 3C) and the PAS staining showed no glycogen deposition (Fig. 3E). After 16 weeks of overload, αCA was still abundantly expressed (Fig. 3B) but some regions demonstrated an intense patchy expression of αSKA (between 20% and 40% of total tissue area) (Fig. 3D). PAS staining of the αSKA-positive regions often showed an accumulation of glycogen (Fig. 3F), although not all areas with αSKA-positive cardiomyocytes were PAS-positive.

Bottom Line: Differentiation of foetal cardiomyocytes is accompanied by sequential actin isoform expression, i.e. down-regulation of the 'embryonic' alpha smooth muscle actin, followed by an up-regulation of alpha skeletal actin (alphaSKA) and a final predominant expression of alpha cardiac actin (alphaCA).Immunohistochemistry of alphaCA, alphaSKA and cardiotin was performed on left ventricle biopsies from human patients after coronary bypass surgery.Dedifferentiating cardiomyocytes in vitro revealed a degradation of the contractile apparatus and local re-expression of alphaSKA.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular Cell Biology, Maastricht University, Maastricht, The Netherlands.

ABSTRACT
Differentiation of foetal cardiomyocytes is accompanied by sequential actin isoform expression, i.e. down-regulation of the 'embryonic' alpha smooth muscle actin, followed by an up-regulation of alpha skeletal actin (alphaSKA) and a final predominant expression of alpha cardiac actin (alphaCA). Our objective was to detect whether re-expression of alphaSKA occurred during cardiomyocyte dedifferentiation, a phenomenon that has been observed in different pathologies characterized by myocardial dysfunction. Immunohistochemistry of alphaCA, alphaSKA and cardiotin was performed on left ventricle biopsies from human patients after coronary bypass surgery. Furthermore, actin isoform expression was investigated in left ventricle samples of rabbit hearts suffering from pressure- and volume-overload and in adult rabbit ventricular cardiomyocytes during dedifferentiation in vitro. Atrial goat samples up to 16 weeks of sustained atrial fibrillation (AF) were studied ultrastructurally and were immunostained for alphaCA and alphaSKA. Up-regulation of alphaSKA was observed in human ventricular cardiomyocytes showing down-regulation of alphaCA and cardiotin. A patchy re-expression pattern of alphaSKA was observed in rabbit left ventricular tissue subjected to pressure- and volume-overload. Dedifferentiating cardiomyocytes in vitro revealed a degradation of the contractile apparatus and local re-expression of alphaSKA. Comparable alphaSKA staining patterns were found in several areas of atrial goat tissue during 16 weeks of AF together with a progressive glycogen accumulation at the same time intervals. The expression of alphaSKA in adult dedifferentiating cardiomyocytes, in combination with PAS-positive glycogen and decreased cardiotin expression, offers an additional tool in the evaluation of myocardial dysfunction and indicates major changes in the contractile properties of these cells.

Show MeSH
Related in: MedlinePlus