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The CXC chemokine cCAF stimulates precocious deposition of ECM molecules by wound fibroblasts, accelerating development of granulation tissue.

Feugate JE, Wong L, Li QJ, Martins-Green M - BMC Cell Biol. (2002)

Bottom Line: In contrast, stimulation of fibronectin and collagen I both require the entire molecule and do not involve changes in gene expression.Fibronectin accumulation appears to be linked to tenascin production, and collagen I to decreased MMP-1 levels.In addition, cCAF is chemotactic for fibroblasts and accelerates their migration.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Cell Biology and Neuroscience, University of California, Riverside, California, USA. feugate@citrus.ucr.edu

ABSTRACT

Background: During wound repair, fibroblasts orchestrate replacement of the provisional matrix formed during clotting with tenascin, cellular fibronectin and collagen III. These, in turn, are critical for migration of endothelial cells, keratinocytes and additional fibroblasts into the wound site. Fibroblasts are also important in the deposition of collagen I during scar formation. The CXC chemokine chicken Chemotactic and Angiogenic Factor (cCAF), is highly expressed by fibroblasts after wounding and during development of the granulation tissue, especially in areas where extracellular matrix (ECM) is abundant. We hypothesized that cCAF stimulates fibroblasts to produce these matrix molecules.

Results: Here we show that this chemokine can stimulate precocious deposition of tenascin, fibronectin and collagen I, but not collagen III. Studies in culture and in vivo show that tenascin stimulation can also be achieved by the N-terminal 15 aas of the protein and occurs at the level of gene expression. In contrast, stimulation of fibronectin and collagen I both require the entire molecule and do not involve changes in gene expression. Fibronectin accumulation appears to be linked to tenascin production, and collagen I to decreased MMP-1 levels. In addition, cCAF is chemotactic for fibroblasts and accelerates their migration.

Conclusions: These previously unknown functions for chemokines suggest that cCAF, the chicken orthologue of human IL-8, enhances healing by rapidly chemoattracting fibroblasts into the wound site and stimulating them to produce ECM molecules, leading to precocious development of granulation tissue. This acceleration of the repair process may have important application to healing of impaired wounds.

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Levels of TN in the granulation tissue of excision wounds. Paraffin-embedded sections of excision wounds treated every other day with vehicle or 1 μg cCAF were immunostained with an antibody against TN. At 3 days after wounding, control wounds (A) show almost no labeling for TN whereas those treated with cCAF already show substantial labeling for TN (B). (C) Immunoblot analysis of proteins extracted from treated and control tissues reveals that treatment with cCAF results in greatly increased levels of TN within 3 days after wounding, but that by seven days, the amount of TN in the treated wounds had decreased whereas untreated wounds showed levels similar to those of cCAF treated at 3 days. All lanes contain equal amounts of total protein, as measured by the DC protein assay (BioRad).
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Figure 2: Levels of TN in the granulation tissue of excision wounds. Paraffin-embedded sections of excision wounds treated every other day with vehicle or 1 μg cCAF were immunostained with an antibody against TN. At 3 days after wounding, control wounds (A) show almost no labeling for TN whereas those treated with cCAF already show substantial labeling for TN (B). (C) Immunoblot analysis of proteins extracted from treated and control tissues reveals that treatment with cCAF results in greatly increased levels of TN within 3 days after wounding, but that by seven days, the amount of TN in the treated wounds had decreased whereas untreated wounds showed levels similar to those of cCAF treated at 3 days. All lanes contain equal amounts of total protein, as measured by the DC protein assay (BioRad).

Mentions: To determine whether this effect is also observed in vivo, excision wounds were made on the underside of wings of 2 week-old chicks. To avoid variations in genetic background, for each bird one wing was treated with vehicle and the other with cCAF, and treatments were applied every other day for 5 days. In normal wound healing, TN appeared at days 2–3 and disappeared during remodeling which begins around day 10 after wounding. Therefore, tissues were collected at days 3 and 7 after wounding and analyzed for TN by immunostaining and western blot analysis (Fig. 2A &2B). Immunoblot analysis of protein extracted from control wounds confirmed that TN deposition begun by 3 days and that it increased dramatically by 7 days (Fig. 2C, Control). In contrast, by 3 days, cCAF-treated wounds already contained as much TN as the control at 7 days and that by 7 days, the TN is dramatically reduced by the ongoing processes of repair (Fig 2C, cCAF). Thus, the addition of the chemokine to wounds shifts the peak of TN in the wound tissues to earlier stages of wound healing than in control wounds.


The CXC chemokine cCAF stimulates precocious deposition of ECM molecules by wound fibroblasts, accelerating development of granulation tissue.

Feugate JE, Wong L, Li QJ, Martins-Green M - BMC Cell Biol. (2002)

Levels of TN in the granulation tissue of excision wounds. Paraffin-embedded sections of excision wounds treated every other day with vehicle or 1 μg cCAF were immunostained with an antibody against TN. At 3 days after wounding, control wounds (A) show almost no labeling for TN whereas those treated with cCAF already show substantial labeling for TN (B). (C) Immunoblot analysis of proteins extracted from treated and control tissues reveals that treatment with cCAF results in greatly increased levels of TN within 3 days after wounding, but that by seven days, the amount of TN in the treated wounds had decreased whereas untreated wounds showed levels similar to those of cCAF treated at 3 days. All lanes contain equal amounts of total protein, as measured by the DC protein assay (BioRad).
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Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC117214&req=5

Figure 2: Levels of TN in the granulation tissue of excision wounds. Paraffin-embedded sections of excision wounds treated every other day with vehicle or 1 μg cCAF were immunostained with an antibody against TN. At 3 days after wounding, control wounds (A) show almost no labeling for TN whereas those treated with cCAF already show substantial labeling for TN (B). (C) Immunoblot analysis of proteins extracted from treated and control tissues reveals that treatment with cCAF results in greatly increased levels of TN within 3 days after wounding, but that by seven days, the amount of TN in the treated wounds had decreased whereas untreated wounds showed levels similar to those of cCAF treated at 3 days. All lanes contain equal amounts of total protein, as measured by the DC protein assay (BioRad).
Mentions: To determine whether this effect is also observed in vivo, excision wounds were made on the underside of wings of 2 week-old chicks. To avoid variations in genetic background, for each bird one wing was treated with vehicle and the other with cCAF, and treatments were applied every other day for 5 days. In normal wound healing, TN appeared at days 2–3 and disappeared during remodeling which begins around day 10 after wounding. Therefore, tissues were collected at days 3 and 7 after wounding and analyzed for TN by immunostaining and western blot analysis (Fig. 2A &2B). Immunoblot analysis of protein extracted from control wounds confirmed that TN deposition begun by 3 days and that it increased dramatically by 7 days (Fig. 2C, Control). In contrast, by 3 days, cCAF-treated wounds already contained as much TN as the control at 7 days and that by 7 days, the TN is dramatically reduced by the ongoing processes of repair (Fig 2C, cCAF). Thus, the addition of the chemokine to wounds shifts the peak of TN in the wound tissues to earlier stages of wound healing than in control wounds.

Bottom Line: In contrast, stimulation of fibronectin and collagen I both require the entire molecule and do not involve changes in gene expression.Fibronectin accumulation appears to be linked to tenascin production, and collagen I to decreased MMP-1 levels.In addition, cCAF is chemotactic for fibroblasts and accelerates their migration.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Cell Biology and Neuroscience, University of California, Riverside, California, USA. feugate@citrus.ucr.edu

ABSTRACT

Background: During wound repair, fibroblasts orchestrate replacement of the provisional matrix formed during clotting with tenascin, cellular fibronectin and collagen III. These, in turn, are critical for migration of endothelial cells, keratinocytes and additional fibroblasts into the wound site. Fibroblasts are also important in the deposition of collagen I during scar formation. The CXC chemokine chicken Chemotactic and Angiogenic Factor (cCAF), is highly expressed by fibroblasts after wounding and during development of the granulation tissue, especially in areas where extracellular matrix (ECM) is abundant. We hypothesized that cCAF stimulates fibroblasts to produce these matrix molecules.

Results: Here we show that this chemokine can stimulate precocious deposition of tenascin, fibronectin and collagen I, but not collagen III. Studies in culture and in vivo show that tenascin stimulation can also be achieved by the N-terminal 15 aas of the protein and occurs at the level of gene expression. In contrast, stimulation of fibronectin and collagen I both require the entire molecule and do not involve changes in gene expression. Fibronectin accumulation appears to be linked to tenascin production, and collagen I to decreased MMP-1 levels. In addition, cCAF is chemotactic for fibroblasts and accelerates their migration.

Conclusions: These previously unknown functions for chemokines suggest that cCAF, the chicken orthologue of human IL-8, enhances healing by rapidly chemoattracting fibroblasts into the wound site and stimulating them to produce ECM molecules, leading to precocious development of granulation tissue. This acceleration of the repair process may have important application to healing of impaired wounds.

Show MeSH
Related in: MedlinePlus