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A central function for perlecan in skeletal muscle and cardiovascular development.

Zoeller JJ, McQuillan A, Whitelock J, Ho SY, Iozzo RV - J. Cell Biol. (2008)

Bottom Line: In the perlecan morphants, primary intersegmental vessel sprouts, which develop through angiogenesis, fail to extend and show reduced protrusive activity.The phenotype is partially rescued by microinjection of human perlecan or endorepellin.These findings indicate that perlecan is essential for the integrity of somitic muscle and developmental angiogenesis and that endorepellin mediates most of these biological activities.

View Article: PubMed Central - PubMed

Affiliation: Department of Pathology, Anatomy, and Cell, Thomas Jefferson University, Philadelphia, PA 19107, USA.

ABSTRACT
Perlecan's developmental functions are difficult to dissect in placental animals because perlecan disruption is embryonic lethal. In contrast to mammals, cardiovascular function is not essential for early zebrafish development because the embryos obtain adequate oxygen by diffusion. In this study, we use targeted protein depletion coupled with protein-based rescue experiments to investigate the involvement of perlecan and its C-terminal domain V/endorepellin in zebrafish development. The perlecan morphants show a severe myopathy characterized by abnormal actin filament orientation and disorganized sarcomeres, suggesting an involvement of perlecan in myopathies. In the perlecan morphants, primary intersegmental vessel sprouts, which develop through angiogenesis, fail to extend and show reduced protrusive activity. Live videomicroscopy confirms the abnormal swimming pattern caused by the myopathy and anomalous head and trunk vessel circulation. The phenotype is partially rescued by microinjection of human perlecan or endorepellin. These findings indicate that perlecan is essential for the integrity of somitic muscle and developmental angiogenesis and that endorepellin mediates most of these biological activities.

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Ultrastructural analysis of perlecan morphant embryos. (A and B) Parasagittal epon sections stained with toluidine blue from 4 dpf control (A) and MO-DV morphant embryos (B). Note the irregular structure and organization of the morphant's skeletal muscle and associated abnormal u-shaped myoseptal boundaries. The DA appears collapsed in the morphant and devoid of blood cells. NC, notochord; DA, dorsal aorta; PCV, posterior cardinal vein. (C–I) A comparison of morphant and control basement membrane structure. Electron microscopy of the vascular (C–E), epithelial (F and G), and notochord basement membranes (BM; H and I) suggest that morpholino-based perlecan knockdown does not compromise the integrity of the basement membrane. Bars: (A and B) 25 μm; (C–I) 1 μm.
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fig4: Ultrastructural analysis of perlecan morphant embryos. (A and B) Parasagittal epon sections stained with toluidine blue from 4 dpf control (A) and MO-DV morphant embryos (B). Note the irregular structure and organization of the morphant's skeletal muscle and associated abnormal u-shaped myoseptal boundaries. The DA appears collapsed in the morphant and devoid of blood cells. NC, notochord; DA, dorsal aorta; PCV, posterior cardinal vein. (C–I) A comparison of morphant and control basement membrane structure. Electron microscopy of the vascular (C–E), epithelial (F and G), and notochord basement membranes (BM; H and I) suggest that morpholino-based perlecan knockdown does not compromise the integrity of the basement membrane. Bars: (A and B) 25 μm; (C–I) 1 μm.

Mentions: Longitudinal sections of the trunk of 4-dpf control zebrafish showed a well-formed DA filled with red cells and a properly developed PCV (Fig. 4 A). In contrast, in the perlecan morphants, the lumen of the DA was often collapsed and devoid of erythrocytes at 4 dpf (Fig. 4 B), although at earlier time points, the lumen was patent with circulation (see Perlecan is essential for developmental angiogenesis...). In addition, we observed a significant disruption of the muscular architecture in the perlecan morphants, with numerous vacuolizations and nucleated cells indicating muscle regeneration (Fig. 4 B). These lesions were found throughout the entire myotome, suggesting an essential role for perlecan in muscle development and maintenance. Ultrastructural analysis of various basement membranes, including vessels, skin, and notochord, showed no significant alterations in the morphants (Fig. 4, C–I), which is in agreement with the perlecan- mice in which basement membrane assembly is developmentally normal (Arikawa-Hirasawa et al., 1999; Costell et al., 1999).


A central function for perlecan in skeletal muscle and cardiovascular development.

Zoeller JJ, McQuillan A, Whitelock J, Ho SY, Iozzo RV - J. Cell Biol. (2008)

Ultrastructural analysis of perlecan morphant embryos. (A and B) Parasagittal epon sections stained with toluidine blue from 4 dpf control (A) and MO-DV morphant embryos (B). Note the irregular structure and organization of the morphant's skeletal muscle and associated abnormal u-shaped myoseptal boundaries. The DA appears collapsed in the morphant and devoid of blood cells. NC, notochord; DA, dorsal aorta; PCV, posterior cardinal vein. (C–I) A comparison of morphant and control basement membrane structure. Electron microscopy of the vascular (C–E), epithelial (F and G), and notochord basement membranes (BM; H and I) suggest that morpholino-based perlecan knockdown does not compromise the integrity of the basement membrane. Bars: (A and B) 25 μm; (C–I) 1 μm.
© Copyright Policy
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC2315682&req=5

fig4: Ultrastructural analysis of perlecan morphant embryos. (A and B) Parasagittal epon sections stained with toluidine blue from 4 dpf control (A) and MO-DV morphant embryos (B). Note the irregular structure and organization of the morphant's skeletal muscle and associated abnormal u-shaped myoseptal boundaries. The DA appears collapsed in the morphant and devoid of blood cells. NC, notochord; DA, dorsal aorta; PCV, posterior cardinal vein. (C–I) A comparison of morphant and control basement membrane structure. Electron microscopy of the vascular (C–E), epithelial (F and G), and notochord basement membranes (BM; H and I) suggest that morpholino-based perlecan knockdown does not compromise the integrity of the basement membrane. Bars: (A and B) 25 μm; (C–I) 1 μm.
Mentions: Longitudinal sections of the trunk of 4-dpf control zebrafish showed a well-formed DA filled with red cells and a properly developed PCV (Fig. 4 A). In contrast, in the perlecan morphants, the lumen of the DA was often collapsed and devoid of erythrocytes at 4 dpf (Fig. 4 B), although at earlier time points, the lumen was patent with circulation (see Perlecan is essential for developmental angiogenesis...). In addition, we observed a significant disruption of the muscular architecture in the perlecan morphants, with numerous vacuolizations and nucleated cells indicating muscle regeneration (Fig. 4 B). These lesions were found throughout the entire myotome, suggesting an essential role for perlecan in muscle development and maintenance. Ultrastructural analysis of various basement membranes, including vessels, skin, and notochord, showed no significant alterations in the morphants (Fig. 4, C–I), which is in agreement with the perlecan- mice in which basement membrane assembly is developmentally normal (Arikawa-Hirasawa et al., 1999; Costell et al., 1999).

Bottom Line: In the perlecan morphants, primary intersegmental vessel sprouts, which develop through angiogenesis, fail to extend and show reduced protrusive activity.The phenotype is partially rescued by microinjection of human perlecan or endorepellin.These findings indicate that perlecan is essential for the integrity of somitic muscle and developmental angiogenesis and that endorepellin mediates most of these biological activities.

View Article: PubMed Central - PubMed

Affiliation: Department of Pathology, Anatomy, and Cell, Thomas Jefferson University, Philadelphia, PA 19107, USA.

ABSTRACT
Perlecan's developmental functions are difficult to dissect in placental animals because perlecan disruption is embryonic lethal. In contrast to mammals, cardiovascular function is not essential for early zebrafish development because the embryos obtain adequate oxygen by diffusion. In this study, we use targeted protein depletion coupled with protein-based rescue experiments to investigate the involvement of perlecan and its C-terminal domain V/endorepellin in zebrafish development. The perlecan morphants show a severe myopathy characterized by abnormal actin filament orientation and disorganized sarcomeres, suggesting an involvement of perlecan in myopathies. In the perlecan morphants, primary intersegmental vessel sprouts, which develop through angiogenesis, fail to extend and show reduced protrusive activity. Live videomicroscopy confirms the abnormal swimming pattern caused by the myopathy and anomalous head and trunk vessel circulation. The phenotype is partially rescued by microinjection of human perlecan or endorepellin. These findings indicate that perlecan is essential for the integrity of somitic muscle and developmental angiogenesis and that endorepellin mediates most of these biological activities.

Show MeSH
Related in: MedlinePlus