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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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Differential expression of the PPARs in mouse epidermis. (A) RNase protection analysis of PPAR mRNA during mouse skin development. Total lysates of skin from day 15.5 to 18.5 embryos (E15.5–E18.5), newborn (NB), 5- and 9-d-old (+5, +9), and adult mice were hybridized with radiolabeled probes specific for PPARα, PPARβ, PPARγ, and L27 mRNA (a). The amount of mRNA for each PPAR isotype was quantified based on the L27 mRNA amount and on the specific activity of each probe (b; n = 3–6). (B) In situ hybridization analysis of PPAR expression during fetal development. Cryosections of mouse skin from embryonic day 13.5–18.5 (E13.5–18.5) were hematoxilin and eosin stained (HE) or hybridized with specific antisense digoxygenin–labeled riboprobes (PPARα, β, or γ). (C) In situ hybridization analysis of PPAR expression during post natal growth. Cryosections of mouse skin from newborn (NB), 5- or 9-d-old pups (+5, +9) and adult animals were hematoxilin/eosin stained (HE) or hybridized with specific antisense digoxygenin-labeled riboprobes (PPARα, β, or γ). Arrows indicate the epidermis/dermis interface. For both B and C, a similar pattern of expression was observed for each time point in five different mice from independent litters. Bars, 80 μm.
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fig1: Differential expression of the PPARs in mouse epidermis. (A) RNase protection analysis of PPAR mRNA during mouse skin development. Total lysates of skin from day 15.5 to 18.5 embryos (E15.5–E18.5), newborn (NB), 5- and 9-d-old (+5, +9), and adult mice were hybridized with radiolabeled probes specific for PPARα, PPARβ, PPARγ, and L27 mRNA (a). The amount of mRNA for each PPAR isotype was quantified based on the L27 mRNA amount and on the specific activity of each probe (b; n = 3–6). (B) In situ hybridization analysis of PPAR expression during fetal development. Cryosections of mouse skin from embryonic day 13.5–18.5 (E13.5–18.5) were hematoxilin and eosin stained (HE) or hybridized with specific antisense digoxygenin–labeled riboprobes (PPARα, β, or γ). (C) In situ hybridization analysis of PPAR expression during post natal growth. Cryosections of mouse skin from newborn (NB), 5- or 9-d-old pups (+5, +9) and adult animals were hematoxilin/eosin stained (HE) or hybridized with specific antisense digoxygenin-labeled riboprobes (PPARα, β, or γ). Arrows indicate the epidermis/dermis interface. For both B and C, a similar pattern of expression was observed for each time point in five different mice from independent litters. Bars, 80 μm.

Mentions: PPAR gene expression in the mouse skin was analyzed by RNase protection assay from day 15.5 of gestation until adulthood (Fig. 1 A). Total skin extracts, including the epidermis and the dermis, were prepared and PPAR mRNA levels were analyzed using radiolabeled PPARα-, β-, and γ-specific probes. The three PPAR isotypes were found to be expressed both in embryonic and in postnatal developing skin at all the stages analyzed (Fig. 1 A). Normalization (L27 and specific activities of the probes) and quantification of the results revealed that PPARα is the least abundant isotype during development, except at embryonic day 15.5. The level of expression of PPARβ, which is ∼1.5 higher than PPARα at E15.5, steadily decreases until after birth. At day 15.5 of gestation, PPARγ is the least expressed PPAR isotype (1.5 and 2–3 times lower than PPARα and PPARβ, respectively). After a twofold increase during late embryonic development, the PPARγ expression level decreases in the postnatal period. In the adult skin, PPARα and PPARγ are low, with PPARβ remaining the highest expressed isotype.


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)

Differential expression of the PPARs in mouse epidermis. (A) RNase protection analysis of PPAR mRNA during mouse skin development. Total lysates of skin from day 15.5 to 18.5 embryos (E15.5–E18.5), newborn (NB), 5- and 9-d-old (+5, +9), and adult mice were hybridized with radiolabeled probes specific for PPARα, PPARβ, PPARγ, and L27 mRNA (a). The amount of mRNA for each PPAR isotype was quantified based on the L27 mRNA amount and on the specific activity of each probe (b; n = 3–6). (B) In situ hybridization analysis of PPAR expression during fetal development. Cryosections of mouse skin from embryonic day 13.5–18.5 (E13.5–18.5) were hematoxilin and eosin stained (HE) or hybridized with specific antisense digoxygenin–labeled riboprobes (PPARα, β, or γ). (C) In situ hybridization analysis of PPAR expression during post natal growth. Cryosections of mouse skin from newborn (NB), 5- or 9-d-old pups (+5, +9) and adult animals were hematoxilin/eosin stained (HE) or hybridized with specific antisense digoxygenin-labeled riboprobes (PPARα, β, or γ). Arrows indicate the epidermis/dermis interface. For both B and C, a similar pattern of expression was observed for each time point in five different mice from independent litters. Bars, 80 μm.
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC2196455&req=5

fig1: Differential expression of the PPARs in mouse epidermis. (A) RNase protection analysis of PPAR mRNA during mouse skin development. Total lysates of skin from day 15.5 to 18.5 embryos (E15.5–E18.5), newborn (NB), 5- and 9-d-old (+5, +9), and adult mice were hybridized with radiolabeled probes specific for PPARα, PPARβ, PPARγ, and L27 mRNA (a). The amount of mRNA for each PPAR isotype was quantified based on the L27 mRNA amount and on the specific activity of each probe (b; n = 3–6). (B) In situ hybridization analysis of PPAR expression during fetal development. Cryosections of mouse skin from embryonic day 13.5–18.5 (E13.5–18.5) were hematoxilin and eosin stained (HE) or hybridized with specific antisense digoxygenin–labeled riboprobes (PPARα, β, or γ). (C) In situ hybridization analysis of PPAR expression during post natal growth. Cryosections of mouse skin from newborn (NB), 5- or 9-d-old pups (+5, +9) and adult animals were hematoxilin/eosin stained (HE) or hybridized with specific antisense digoxygenin-labeled riboprobes (PPARα, β, or γ). Arrows indicate the epidermis/dermis interface. For both B and C, a similar pattern of expression was observed for each time point in five different mice from independent litters. Bars, 80 μm.
Mentions: PPAR gene expression in the mouse skin was analyzed by RNase protection assay from day 15.5 of gestation until adulthood (Fig. 1 A). Total skin extracts, including the epidermis and the dermis, were prepared and PPAR mRNA levels were analyzed using radiolabeled PPARα-, β-, and γ-specific probes. The three PPAR isotypes were found to be expressed both in embryonic and in postnatal developing skin at all the stages analyzed (Fig. 1 A). Normalization (L27 and specific activities of the probes) and quantification of the results revealed that PPARα is the least abundant isotype during development, except at embryonic day 15.5. The level of expression of PPARβ, which is ∼1.5 higher than PPARα at E15.5, steadily decreases until after birth. At day 15.5 of gestation, PPARγ is the least expressed PPAR isotype (1.5 and 2–3 times lower than PPARα and PPARβ, respectively). After a twofold increase during late embryonic development, the PPARγ expression level decreases in the postnatal period. In the adult skin, PPARα and PPARγ are low, with PPARβ remaining the highest expressed isotype.

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