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Impaired skin wound healing in peroxisome proliferator-activated receptor (PPAR)alpha and PPARbeta mutant mice.

Michalik L, Desvergne B, Tan NS, Basu-Modak S, Escher P, Rieusset J, Peters JM, Kaya G, Gonzalez FJ, Zakany J, Metzger D, Chambon P, Duboule D, Wahli W - J. Cell Biol. (2001)

Bottom Line: Interestingly, PPARalpha and beta expression is reactivated in the adult epidermis after various stimuli, resulting in keratinocyte proliferation and differentiation such as tetradecanoylphorbol acetate topical application, hair plucking, or skin wound healing.PPARalpha is mainly involved in the early inflammation phase of the healing, whereas PPARbeta is implicated in the control of keratinocyte proliferation.In addition and very interestingly, PPARbeta mutant primary keratinocytes show impaired adhesion and migration properties.

View Article: PubMed Central - PubMed

Affiliation: Institut de Biologie Animale, Université de Lausanne, Bâtiment de Biologie, CH-1015 Lausanne, Switzerland.

ABSTRACT
We show here that the alpha, beta, and gamma isotypes of peroxisome proliferator-activated receptor (PPAR) are expressed in the mouse epidermis during fetal development and that they disappear progressively from the interfollicular epithelium after birth. Interestingly, PPARalpha and beta expression is reactivated in the adult epidermis after various stimuli, resulting in keratinocyte proliferation and differentiation such as tetradecanoylphorbol acetate topical application, hair plucking, or skin wound healing. Using PPARalpha, beta, and gamma mutant mice, we demonstrate that PPARalpha and beta are important for the rapid epithelialization of a skin wound and that each of them plays a specific role in this process. PPARalpha is mainly involved in the early inflammation phase of the healing, whereas PPARbeta is implicated in the control of keratinocyte proliferation. In addition and very interestingly, PPARbeta mutant primary keratinocytes show impaired adhesion and migration properties. Thus, the findings presented here reveal unpredicted roles for PPARalpha and beta in adult mouse epidermal repair.

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PPARβ1/− primary keratinocytes show impaired adhesion and migration properties. Primary keratinocytes isolated from skin of PPARβ+/+ (a–d) or PPARβ+/− (e–h) newborn pups. (a) Wild-type keratinocytes 24 h after plating; (e) PPARβ+/− keratinocytes 3 d after plating. (b–d and f–h) Wounded cultures of primary keratinocytes: scrape wounds were made at day 0 (day 0 corresponds to the obtention of 70–80% confluent cell culture) (b and f). Panels c and g and d and h represent the wounds at day 2 and 4 after scraping, respectively. Bar: (a, b, e, f, and insets) 100 μm; (c, d, g, and h) 200 μm.
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fig9: PPARβ1/− primary keratinocytes show impaired adhesion and migration properties. Primary keratinocytes isolated from skin of PPARβ+/+ (a–d) or PPARβ+/− (e–h) newborn pups. (a) Wild-type keratinocytes 24 h after plating; (e) PPARβ+/− keratinocytes 3 d after plating. (b–d and f–h) Wounded cultures of primary keratinocytes: scrape wounds were made at day 0 (day 0 corresponds to the obtention of 70–80% confluent cell culture) (b and f). Panels c and g and d and h represent the wounds at day 2 and 4 after scraping, respectively. Bar: (a, b, e, f, and insets) 100 μm; (c, d, g, and h) 200 μm.

Mentions: Since the hypothesis of a defect in PPARβ+/− skin elasticity was unlikely, the adhesion and migration capacities of the PPARβ-mutated keratinocytes were studied in vitro using primary keratinocyte cultures. Keratinocytes were isolated from the skin of wild-type and PPARβ+/− newborn pups. PPARβ mutant keratinocytes in culture immediately showed impaired adhesion capacities: they adopted a rounded shape and only adhered 4 d after seeding, whereas the wild-type primary keratinocytes spread and adhered easily 24 h after seeding (Fig. 9) . However, despite this adhesion defect and delay in adherence, the PPARβ mutant keratinocytes remain viable. Seeding of more mutant keratinocytes compared with the wild-type cells (see Materials and methods) allowed us to obtain 70–80% confluent cultures for both keratinocyte genotypes, allowing the study of in vitro healing of a scraping wound. After scraping of the culture, the wild-type and mutant cells behaved very differently at the edges of the in vitro wound. As shown in Fig. 9, the PPARβ wild-type keratinocytes remained in tight contact with each other and scraping resulted in folds at the edges (Fig. 9 b). On the contrary, the PPARβ+/− keratinocytes were easier to detach, and the produced edges were blunt (Fig. 9 f). Once the PPARβ wild-type keratinocytes started to migrate out of the edges, their migration rate was higher compared with that of the PPARβ+/− keratinocytes (Fig. 9, c, d, g, and h). This in vitro result indicates that the migration properties of the PPARβ mutant keratinocytes are impaired, consistent with observations in whole animal. Indeed, in vivo, the number of keratinocytes per surface unit is slightly higher at the edges of skin wound in the PPARβ mutant animals compared with the wild-type mice, also indicating that in vivo as well, the migration is slower in PPARβ mutant cells (data not shown).


Impaired skin wound healing in peroxisome proliferator-activated receptor (PPAR)alpha and PPARbeta mutant mice.

Michalik L, Desvergne B, Tan NS, Basu-Modak S, Escher P, Rieusset J, Peters JM, Kaya G, Gonzalez FJ, Zakany J, Metzger D, Chambon P, Duboule D, Wahli W - J. Cell Biol. (2001)

PPARβ1/− primary keratinocytes show impaired adhesion and migration properties. Primary keratinocytes isolated from skin of PPARβ+/+ (a–d) or PPARβ+/− (e–h) newborn pups. (a) Wild-type keratinocytes 24 h after plating; (e) PPARβ+/− keratinocytes 3 d after plating. (b–d and f–h) Wounded cultures of primary keratinocytes: scrape wounds were made at day 0 (day 0 corresponds to the obtention of 70–80% confluent cell culture) (b and f). Panels c and g and d and h represent the wounds at day 2 and 4 after scraping, respectively. Bar: (a, b, e, f, and insets) 100 μm; (c, d, g, and h) 200 μm.
© Copyright Policy
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC2196455&req=5

fig9: PPARβ1/− primary keratinocytes show impaired adhesion and migration properties. Primary keratinocytes isolated from skin of PPARβ+/+ (a–d) or PPARβ+/− (e–h) newborn pups. (a) Wild-type keratinocytes 24 h after plating; (e) PPARβ+/− keratinocytes 3 d after plating. (b–d and f–h) Wounded cultures of primary keratinocytes: scrape wounds were made at day 0 (day 0 corresponds to the obtention of 70–80% confluent cell culture) (b and f). Panels c and g and d and h represent the wounds at day 2 and 4 after scraping, respectively. Bar: (a, b, e, f, and insets) 100 μm; (c, d, g, and h) 200 μm.
Mentions: Since the hypothesis of a defect in PPARβ+/− skin elasticity was unlikely, the adhesion and migration capacities of the PPARβ-mutated keratinocytes were studied in vitro using primary keratinocyte cultures. Keratinocytes were isolated from the skin of wild-type and PPARβ+/− newborn pups. PPARβ mutant keratinocytes in culture immediately showed impaired adhesion capacities: they adopted a rounded shape and only adhered 4 d after seeding, whereas the wild-type primary keratinocytes spread and adhered easily 24 h after seeding (Fig. 9) . However, despite this adhesion defect and delay in adherence, the PPARβ mutant keratinocytes remain viable. Seeding of more mutant keratinocytes compared with the wild-type cells (see Materials and methods) allowed us to obtain 70–80% confluent cultures for both keratinocyte genotypes, allowing the study of in vitro healing of a scraping wound. After scraping of the culture, the wild-type and mutant cells behaved very differently at the edges of the in vitro wound. As shown in Fig. 9, the PPARβ wild-type keratinocytes remained in tight contact with each other and scraping resulted in folds at the edges (Fig. 9 b). On the contrary, the PPARβ+/− keratinocytes were easier to detach, and the produced edges were blunt (Fig. 9 f). Once the PPARβ wild-type keratinocytes started to migrate out of the edges, their migration rate was higher compared with that of the PPARβ+/− keratinocytes (Fig. 9, c, d, g, and h). This in vitro result indicates that the migration properties of the PPARβ mutant keratinocytes are impaired, consistent with observations in whole animal. Indeed, in vivo, the number of keratinocytes per surface unit is slightly higher at the edges of skin wound in the PPARβ mutant animals compared with the wild-type mice, also indicating that in vivo as well, the migration is slower in PPARβ mutant cells (data not shown).

Bottom Line: Interestingly, PPARalpha and beta expression is reactivated in the adult epidermis after various stimuli, resulting in keratinocyte proliferation and differentiation such as tetradecanoylphorbol acetate topical application, hair plucking, or skin wound healing.PPARalpha is mainly involved in the early inflammation phase of the healing, whereas PPARbeta is implicated in the control of keratinocyte proliferation.In addition and very interestingly, PPARbeta mutant primary keratinocytes show impaired adhesion and migration properties.

View Article: PubMed Central - PubMed

Affiliation: Institut de Biologie Animale, Université de Lausanne, Bâtiment de Biologie, CH-1015 Lausanne, Switzerland.

ABSTRACT
We show here that the alpha, beta, and gamma isotypes of peroxisome proliferator-activated receptor (PPAR) are expressed in the mouse epidermis during fetal development and that they disappear progressively from the interfollicular epithelium after birth. Interestingly, PPARalpha and beta expression is reactivated in the adult epidermis after various stimuli, resulting in keratinocyte proliferation and differentiation such as tetradecanoylphorbol acetate topical application, hair plucking, or skin wound healing. Using PPARalpha, beta, and gamma mutant mice, we demonstrate that PPARalpha and beta are important for the rapid epithelialization of a skin wound and that each of them plays a specific role in this process. PPARalpha is mainly involved in the early inflammation phase of the healing, whereas PPARbeta is implicated in the control of keratinocyte proliferation. In addition and very interestingly, PPARbeta mutant primary keratinocytes show impaired adhesion and migration properties. Thus, the findings presented here reveal unpredicted roles for PPARalpha and beta in adult mouse epidermal repair.

Show MeSH
Related in: MedlinePlus