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Differential expression of lumican and fibromodulin regulate collagen fibrillogenesis in developing mouse tendons.

Ezura Y, Chakravarti S, Oldberg A, Chervoneva I, Birk DE - J. Cell Biol. (2000)

Bottom Line: With development, the amount of lumican decreases to barely detectable levels while fibromodulin increases significantly, and these changing patterns may regulate this process.The observed increased ratio of fibromodulin to lumican and a competition for the same binding site could mediate these transitions.These studies indicate that lumican and fibromodulin have different developmental stage and leucine-rich repeat protein specific functions in the regulation of fibrillogenesis.

View Article: PubMed Central - PubMed

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

ABSTRACT
Collagen fibrillogenesis is finely regulated during development of tissue-specific extracellular matrices. The role(s) of a leucine-rich repeat protein subfamily in the regulation of fibrillogenesis during tendon development were defined. Lumican-, fibromodulin-, and double-deficient mice demonstrated disruptions in fibrillogenesis. With development, the amount of lumican decreases to barely detectable levels while fibromodulin increases significantly, and these changing patterns may regulate this process. Electron microscopic analysis demonstrated structural abnormalities in the fibrils and alterations in the progression through different assembly steps. In lumican-deficient tendons, alterations were observed early and the mature tendon was nearly normal. Fibromodulin-deficient tendons were comparable with the lumican- in early developmental periods and acquired a severe phenotype by maturation. The double-deficient mice had a phenotype that was additive early and comparable with the fibromodulin-deficient mice at maturation. Therefore, lumican and fibromodulin both influence initial assembly of intermediates and the entry into fibril growth, while fibromodulin facilitates the progression through growth steps leading to mature fibrils. The observed increased ratio of fibromodulin to lumican and a competition for the same binding site could mediate these transitions. These studies indicate that lumican and fibromodulin have different developmental stage and leucine-rich repeat protein specific functions in the regulation of fibrillogenesis.

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Lumican and fibromodulin content during normal tendon development. (a) A representative semiquantitative Western analysis of lumican and fibromodulin during development in the normal mouse tendon is presented. Tendons were extracted in 4 M guanidine-HCl at 4 d, 10 d, and 1 mo. 80, 40, and 20 μg of total protein from each time point were loaded onto the gel. The core proteins were transferred, reacted with antilumican or antifibromodulin antisera followed by radiolabeled goat anti–rabbit IgG, and quantitated using phosphoimaging. A duplicate gel stained with Coomassie shows similar amounts of type I collagen in the extracts. (b) The relative lumican and fibromodulin content in the tendon at 4 d, 10 d, and 1 mo postnatal were derived from three independent experiments. The mean values for both lumican and fibromodulin were set to 100 at 4 d and the results were plotted as a function of development (bars indicate SD).
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Figure 3: Lumican and fibromodulin content during normal tendon development. (a) A representative semiquantitative Western analysis of lumican and fibromodulin during development in the normal mouse tendon is presented. Tendons were extracted in 4 M guanidine-HCl at 4 d, 10 d, and 1 mo. 80, 40, and 20 μg of total protein from each time point were loaded onto the gel. The core proteins were transferred, reacted with antilumican or antifibromodulin antisera followed by radiolabeled goat anti–rabbit IgG, and quantitated using phosphoimaging. A duplicate gel stained with Coomassie shows similar amounts of type I collagen in the extracts. (b) The relative lumican and fibromodulin content in the tendon at 4 d, 10 d, and 1 mo postnatal were derived from three independent experiments. The mean values for both lumican and fibromodulin were set to 100 at 4 d and the results were plotted as a function of development (bars indicate SD).

Mentions: The amount of lumican and fibromodulin core protein present during normal development was analyzed using semiquantitative Western analysis. Fibromodulin core protein increased by ∼30–40% from 4 d to 1 mo, while lumican decreased by ∼60–70% during the same period (Fig. 3). The spatial distribution of the core proteins was analyzed by immunofluorescence histochemistry during normal tendon development. Reactivity for lumican and fibromodulin was present throughout the tendon matrix at 10-d postnatal (Fig. 4). Comparable results were observed in the 4-d and 1-mo tendon (data not shown); however, lumican reactivity was decreased in the 1-mo matrix, consistent with the core protein content. This localization to the region of tendon fibril formation rather than a spatially restricted pattern, for example to the tendon sheath, demonstrates that regulatory interactions are possible. The controls without primary antibody or with an irrelevant antibody were negative. Taken together, these data suggest that lumican functions during early stages in fibrillogenesis, while fibromodulin would function throughout this period with a more prominent role in regulation of the later stages. The codistribution of lumican and fibromodulin with collagen fibrils is consistent with the regulation of fibrillogenesis.


Differential expression of lumican and fibromodulin regulate collagen fibrillogenesis in developing mouse tendons.

Ezura Y, Chakravarti S, Oldberg A, Chervoneva I, Birk DE - J. Cell Biol. (2000)

Lumican and fibromodulin content during normal tendon development. (a) A representative semiquantitative Western analysis of lumican and fibromodulin during development in the normal mouse tendon is presented. Tendons were extracted in 4 M guanidine-HCl at 4 d, 10 d, and 1 mo. 80, 40, and 20 μg of total protein from each time point were loaded onto the gel. The core proteins were transferred, reacted with antilumican or antifibromodulin antisera followed by radiolabeled goat anti–rabbit IgG, and quantitated using phosphoimaging. A duplicate gel stained with Coomassie shows similar amounts of type I collagen in the extracts. (b) The relative lumican and fibromodulin content in the tendon at 4 d, 10 d, and 1 mo postnatal were derived from three independent experiments. The mean values for both lumican and fibromodulin were set to 100 at 4 d and the results were plotted as a function of development (bars indicate SD).
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC2169450&req=5

Figure 3: Lumican and fibromodulin content during normal tendon development. (a) A representative semiquantitative Western analysis of lumican and fibromodulin during development in the normal mouse tendon is presented. Tendons were extracted in 4 M guanidine-HCl at 4 d, 10 d, and 1 mo. 80, 40, and 20 μg of total protein from each time point were loaded onto the gel. The core proteins were transferred, reacted with antilumican or antifibromodulin antisera followed by radiolabeled goat anti–rabbit IgG, and quantitated using phosphoimaging. A duplicate gel stained with Coomassie shows similar amounts of type I collagen in the extracts. (b) The relative lumican and fibromodulin content in the tendon at 4 d, 10 d, and 1 mo postnatal were derived from three independent experiments. The mean values for both lumican and fibromodulin were set to 100 at 4 d and the results were plotted as a function of development (bars indicate SD).
Mentions: The amount of lumican and fibromodulin core protein present during normal development was analyzed using semiquantitative Western analysis. Fibromodulin core protein increased by ∼30–40% from 4 d to 1 mo, while lumican decreased by ∼60–70% during the same period (Fig. 3). The spatial distribution of the core proteins was analyzed by immunofluorescence histochemistry during normal tendon development. Reactivity for lumican and fibromodulin was present throughout the tendon matrix at 10-d postnatal (Fig. 4). Comparable results were observed in the 4-d and 1-mo tendon (data not shown); however, lumican reactivity was decreased in the 1-mo matrix, consistent with the core protein content. This localization to the region of tendon fibril formation rather than a spatially restricted pattern, for example to the tendon sheath, demonstrates that regulatory interactions are possible. The controls without primary antibody or with an irrelevant antibody were negative. Taken together, these data suggest that lumican functions during early stages in fibrillogenesis, while fibromodulin would function throughout this period with a more prominent role in regulation of the later stages. The codistribution of lumican and fibromodulin with collagen fibrils is consistent with the regulation of fibrillogenesis.

Bottom Line: With development, the amount of lumican decreases to barely detectable levels while fibromodulin increases significantly, and these changing patterns may regulate this process.The observed increased ratio of fibromodulin to lumican and a competition for the same binding site could mediate these transitions.These studies indicate that lumican and fibromodulin have different developmental stage and leucine-rich repeat protein specific functions in the regulation of fibrillogenesis.

View Article: PubMed Central - PubMed

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

ABSTRACT
Collagen fibrillogenesis is finely regulated during development of tissue-specific extracellular matrices. The role(s) of a leucine-rich repeat protein subfamily in the regulation of fibrillogenesis during tendon development were defined. Lumican-, fibromodulin-, and double-deficient mice demonstrated disruptions in fibrillogenesis. With development, the amount of lumican decreases to barely detectable levels while fibromodulin increases significantly, and these changing patterns may regulate this process. Electron microscopic analysis demonstrated structural abnormalities in the fibrils and alterations in the progression through different assembly steps. In lumican-deficient tendons, alterations were observed early and the mature tendon was nearly normal. Fibromodulin-deficient tendons were comparable with the lumican- in early developmental periods and acquired a severe phenotype by maturation. The double-deficient mice had a phenotype that was additive early and comparable with the fibromodulin-deficient mice at maturation. Therefore, lumican and fibromodulin both influence initial assembly of intermediates and the entry into fibril growth, while fibromodulin facilitates the progression through growth steps leading to mature fibrils. The observed increased ratio of fibromodulin to lumican and a competition for the same binding site could mediate these transitions. These studies indicate that lumican and fibromodulin have different developmental stage and leucine-rich repeat protein specific functions in the regulation of fibrillogenesis.

Show MeSH
Related in: MedlinePlus