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PAR2 absence completely rescues inflammation and ichthyosis caused by altered CAP1/Prss8 expression in mouse skin.

Frateschi S, Camerer E, Crisante G, Rieser S, Membrez M, Charles RP, Beermann F, Stehle JC, Breiden B, Sandhoff K, Rotman S, Haftek M, Wilson A, Ryser S, Steinhoff M, Coughlin SR, Hummler E - Nat Commun (2011)

Bottom Line: K14-CAP1/Prss8 ectopic expression impairs epidermal barrier function and causes skin inflammation characterized by an increase in thymic stromal lymphopoietin levels and immune cell infiltrations.Strikingly, both gross and functional K14-CAP1/Prss8-induced phenotypes are completely negated when superimposed on a PAR2- background, establishing PAR2 as a pivotal mediator of pathogenesis.Our data provide genetic evidence for PAR2 as a downstream effector of CAP1/Prss8 in a signalling cascade that may provide novel therapeutic targets for ichthyoses, pruritus and inflammatory skin diseases.

View Article: PubMed Central - PubMed

Affiliation: Department of Pharmacology and Toxicology, University of Lausanne, Lausanne 1005, Switzerland.

ABSTRACT
Altered serine protease activity is associated with skin disorders in humans and in mice. The serine protease channel-activating protease-1 (CAP1; also termed protease serine S1 family member 8 (Prss8)) is important for epidermal homeostasis and is thus indispensable for postnatal survival in mice, but its roles and effectors in skin pathology are poorly defined. In this paper, we report that transgenic expression in mouse skin of either CAP1/Prss8 (K14-CAP1/Prss8) or protease-activated receptor-2 (PAR2; Grhl3(PAR2/+)), one candidate downstream target, causes epidermal hyperplasia, ichthyosis and itching. K14-CAP1/Prss8 ectopic expression impairs epidermal barrier function and causes skin inflammation characterized by an increase in thymic stromal lymphopoietin levels and immune cell infiltrations. Strikingly, both gross and functional K14-CAP1/Prss8-induced phenotypes are completely negated when superimposed on a PAR2- background, establishing PAR2 as a pivotal mediator of pathogenesis. Our data provide genetic evidence for PAR2 as a downstream effector of CAP1/Prss8 in a signalling cascade that may provide novel therapeutic targets for ichthyoses, pruritus and inflammatory skin diseases.

No MeSH data available.


Related in: MedlinePlus

Altered protein and lipid composition in K14-CAP1/Prss8 epidermis.(a) Epidermal differentiation markers (keratin-14, -6, -1, filaggrin, loricrin and involucrin) as present (green) in both wild-type and transgenic mice. Dotted lines indicate basal membrane. Below: tight junction permeability assay using NHS-LC-biotin (red). Nuclei are counterstained with DAPI (blue). Scale bar represents 20 μm; n=3 mice per group. (b) Western blot analyses demonstrate the expression of filaggrin, loricrin, involucrin, keratin-1 (K1), keratin-6 (K6) and keratin-14 (K14) in skin of transgenic and control mice. Loading is controlled by β-actin and proteins are quantified in (c), n≥4 animals per group. (d) Analysis of unbound stratum corneum lipids by thin layer chromatography in transgenic versus littermate controls. Cholesterol (Chol), ceramide (Cer), free fatty acids (FFA). (e) Analysis of probarrier lipids sphingomyelin (SM), cholesterol sulphate (CSO4) and glucosylceramide (GlcCer). (f) Covalently bound lipids: In K14-CAP1/Prss8 transgenic mice, ceramide (OS) levels (Cer(OS)) were reduced to 6.3% of controls. (Chl: cholesterol, FFA: free fatty acids, ω-OH FA: ω-hydroxy fatty acids), n≥3 mice per group; (c–f) All data are presented as mean±s.e.m. *P<0.05, **P<0.01, ***P<0.001. (g) Electron microscopy of skin of K14-CAP1/Prss8 2-week-old transgenic (n=4) and wild-type littermates (n=3) depicting interface between stratum granulosum (SG) and stratum corneum (SC; left, middle panel). Lamellar bodies are shown in the SG (black) and SC (white arrows). Right panel: intermediate portion of hyperkeratotic scales in transgenic mice. Scale bar represents 200 nm.
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f3: Altered protein and lipid composition in K14-CAP1/Prss8 epidermis.(a) Epidermal differentiation markers (keratin-14, -6, -1, filaggrin, loricrin and involucrin) as present (green) in both wild-type and transgenic mice. Dotted lines indicate basal membrane. Below: tight junction permeability assay using NHS-LC-biotin (red). Nuclei are counterstained with DAPI (blue). Scale bar represents 20 μm; n=3 mice per group. (b) Western blot analyses demonstrate the expression of filaggrin, loricrin, involucrin, keratin-1 (K1), keratin-6 (K6) and keratin-14 (K14) in skin of transgenic and control mice. Loading is controlled by β-actin and proteins are quantified in (c), n≥4 animals per group. (d) Analysis of unbound stratum corneum lipids by thin layer chromatography in transgenic versus littermate controls. Cholesterol (Chol), ceramide (Cer), free fatty acids (FFA). (e) Analysis of probarrier lipids sphingomyelin (SM), cholesterol sulphate (CSO4) and glucosylceramide (GlcCer). (f) Covalently bound lipids: In K14-CAP1/Prss8 transgenic mice, ceramide (OS) levels (Cer(OS)) were reduced to 6.3% of controls. (Chl: cholesterol, FFA: free fatty acids, ω-OH FA: ω-hydroxy fatty acids), n≥3 mice per group; (c–f) All data are presented as mean±s.e.m. *P<0.05, **P<0.01, ***P<0.001. (g) Electron microscopy of skin of K14-CAP1/Prss8 2-week-old transgenic (n=4) and wild-type littermates (n=3) depicting interface between stratum granulosum (SG) and stratum corneum (SC; left, middle panel). Lamellar bodies are shown in the SG (black) and SC (white arrows). Right panel: intermediate portion of hyperkeratotic scales in transgenic mice. Scale bar represents 200 nm.

Mentions: To explore the basis for skin barrier defects observed in K14-CAP1/Prss8 transgenic mice, we first looked for alterations in expression of keratinocyte differentiation markers by immunohistochemistry and western blot. Expression of keratin-1, loricrin, filaggrin and involucrin appeared to be more widespread within the epidermis of K14-CAP1/Prss8 mice, but there was no obvious change in distribution within the differentiated layers (Fig. 3a; Supplementary Fig. S1g), and expression levels were normal with the exception of filaggrin. Levels of all proteolytically cleaved intermediates of filaggrin were increased (Fig. 3b,c; Supplementary Fig. S1h,i). Moreover, the differentiation marker keratin-14, normally expressed exclusively in the stratum basale and hair follicles, was now detected in all nucleated epidermal cell layers. The expression of keratin-6, normally present only in hair follicles, was also detectable in interfollicular keratinocytes (Fig. 3a; Supplementary Fig. S1g), consistent with epidermal hyperplasia.


PAR2 absence completely rescues inflammation and ichthyosis caused by altered CAP1/Prss8 expression in mouse skin.

Frateschi S, Camerer E, Crisante G, Rieser S, Membrez M, Charles RP, Beermann F, Stehle JC, Breiden B, Sandhoff K, Rotman S, Haftek M, Wilson A, Ryser S, Steinhoff M, Coughlin SR, Hummler E - Nat Commun (2011)

Altered protein and lipid composition in K14-CAP1/Prss8 epidermis.(a) Epidermal differentiation markers (keratin-14, -6, -1, filaggrin, loricrin and involucrin) as present (green) in both wild-type and transgenic mice. Dotted lines indicate basal membrane. Below: tight junction permeability assay using NHS-LC-biotin (red). Nuclei are counterstained with DAPI (blue). Scale bar represents 20 μm; n=3 mice per group. (b) Western blot analyses demonstrate the expression of filaggrin, loricrin, involucrin, keratin-1 (K1), keratin-6 (K6) and keratin-14 (K14) in skin of transgenic and control mice. Loading is controlled by β-actin and proteins are quantified in (c), n≥4 animals per group. (d) Analysis of unbound stratum corneum lipids by thin layer chromatography in transgenic versus littermate controls. Cholesterol (Chol), ceramide (Cer), free fatty acids (FFA). (e) Analysis of probarrier lipids sphingomyelin (SM), cholesterol sulphate (CSO4) and glucosylceramide (GlcCer). (f) Covalently bound lipids: In K14-CAP1/Prss8 transgenic mice, ceramide (OS) levels (Cer(OS)) were reduced to 6.3% of controls. (Chl: cholesterol, FFA: free fatty acids, ω-OH FA: ω-hydroxy fatty acids), n≥3 mice per group; (c–f) All data are presented as mean±s.e.m. *P<0.05, **P<0.01, ***P<0.001. (g) Electron microscopy of skin of K14-CAP1/Prss8 2-week-old transgenic (n=4) and wild-type littermates (n=3) depicting interface between stratum granulosum (SG) and stratum corneum (SC; left, middle panel). Lamellar bodies are shown in the SG (black) and SC (white arrows). Right panel: intermediate portion of hyperkeratotic scales in transgenic mice. Scale bar represents 200 nm.
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Related In: Results  -  Collection

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f3: Altered protein and lipid composition in K14-CAP1/Prss8 epidermis.(a) Epidermal differentiation markers (keratin-14, -6, -1, filaggrin, loricrin and involucrin) as present (green) in both wild-type and transgenic mice. Dotted lines indicate basal membrane. Below: tight junction permeability assay using NHS-LC-biotin (red). Nuclei are counterstained with DAPI (blue). Scale bar represents 20 μm; n=3 mice per group. (b) Western blot analyses demonstrate the expression of filaggrin, loricrin, involucrin, keratin-1 (K1), keratin-6 (K6) and keratin-14 (K14) in skin of transgenic and control mice. Loading is controlled by β-actin and proteins are quantified in (c), n≥4 animals per group. (d) Analysis of unbound stratum corneum lipids by thin layer chromatography in transgenic versus littermate controls. Cholesterol (Chol), ceramide (Cer), free fatty acids (FFA). (e) Analysis of probarrier lipids sphingomyelin (SM), cholesterol sulphate (CSO4) and glucosylceramide (GlcCer). (f) Covalently bound lipids: In K14-CAP1/Prss8 transgenic mice, ceramide (OS) levels (Cer(OS)) were reduced to 6.3% of controls. (Chl: cholesterol, FFA: free fatty acids, ω-OH FA: ω-hydroxy fatty acids), n≥3 mice per group; (c–f) All data are presented as mean±s.e.m. *P<0.05, **P<0.01, ***P<0.001. (g) Electron microscopy of skin of K14-CAP1/Prss8 2-week-old transgenic (n=4) and wild-type littermates (n=3) depicting interface between stratum granulosum (SG) and stratum corneum (SC; left, middle panel). Lamellar bodies are shown in the SG (black) and SC (white arrows). Right panel: intermediate portion of hyperkeratotic scales in transgenic mice. Scale bar represents 200 nm.
Mentions: To explore the basis for skin barrier defects observed in K14-CAP1/Prss8 transgenic mice, we first looked for alterations in expression of keratinocyte differentiation markers by immunohistochemistry and western blot. Expression of keratin-1, loricrin, filaggrin and involucrin appeared to be more widespread within the epidermis of K14-CAP1/Prss8 mice, but there was no obvious change in distribution within the differentiated layers (Fig. 3a; Supplementary Fig. S1g), and expression levels were normal with the exception of filaggrin. Levels of all proteolytically cleaved intermediates of filaggrin were increased (Fig. 3b,c; Supplementary Fig. S1h,i). Moreover, the differentiation marker keratin-14, normally expressed exclusively in the stratum basale and hair follicles, was now detected in all nucleated epidermal cell layers. The expression of keratin-6, normally present only in hair follicles, was also detectable in interfollicular keratinocytes (Fig. 3a; Supplementary Fig. S1g), consistent with epidermal hyperplasia.

Bottom Line: K14-CAP1/Prss8 ectopic expression impairs epidermal barrier function and causes skin inflammation characterized by an increase in thymic stromal lymphopoietin levels and immune cell infiltrations.Strikingly, both gross and functional K14-CAP1/Prss8-induced phenotypes are completely negated when superimposed on a PAR2- background, establishing PAR2 as a pivotal mediator of pathogenesis.Our data provide genetic evidence for PAR2 as a downstream effector of CAP1/Prss8 in a signalling cascade that may provide novel therapeutic targets for ichthyoses, pruritus and inflammatory skin diseases.

View Article: PubMed Central - PubMed

Affiliation: Department of Pharmacology and Toxicology, University of Lausanne, Lausanne 1005, Switzerland.

ABSTRACT
Altered serine protease activity is associated with skin disorders in humans and in mice. The serine protease channel-activating protease-1 (CAP1; also termed protease serine S1 family member 8 (Prss8)) is important for epidermal homeostasis and is thus indispensable for postnatal survival in mice, but its roles and effectors in skin pathology are poorly defined. In this paper, we report that transgenic expression in mouse skin of either CAP1/Prss8 (K14-CAP1/Prss8) or protease-activated receptor-2 (PAR2; Grhl3(PAR2/+)), one candidate downstream target, causes epidermal hyperplasia, ichthyosis and itching. K14-CAP1/Prss8 ectopic expression impairs epidermal barrier function and causes skin inflammation characterized by an increase in thymic stromal lymphopoietin levels and immune cell infiltrations. Strikingly, both gross and functional K14-CAP1/Prss8-induced phenotypes are completely negated when superimposed on a PAR2- background, establishing PAR2 as a pivotal mediator of pathogenesis. Our data provide genetic evidence for PAR2 as a downstream effector of CAP1/Prss8 in a signalling cascade that may provide novel therapeutic targets for ichthyoses, pruritus and inflammatory skin diseases.

No MeSH data available.


Related in: MedlinePlus