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Atopic dermatitis-like disease and associated lethal myeloproliferative disorder arise from loss of Notch signaling in the murine skin.

Dumortier A, Durham AD, Di Piazza M, Vauclair S, Koch U, Ferrand G, Ferrero I, Demehri S, Song LL, Farr AG, Leonard WJ, Kopan R, Miele L, Hohl D, Finke D, Radtke F - PLoS ONE (2010)

Bottom Line: The AD-like associated inflammation is accompanied by a myeloproliferative disorder (MPD) characterized by an increase in immature myeloid populations in the bone marrow and spleen.Genetic studies demontrated that G-CSF mediates the MPD as well as changes in the bone marrow microenvironment leading to osteopenia.Our data demonstrate a critical role for Notch in repressing TSLP production in keratinocytes, thereby maintaining integrity of the skin and the hematopoietic system.

View Article: PubMed Central - PubMed

Affiliation: Ecole Polytechnique Fédérale de Lausanne (EPFL SV ISREC), Lausanne, Switzerland.

ABSTRACT

Background: The Notch pathway is essential for proper epidermal differentiation during embryonic skin development. Moreover, skin specific loss of Notch signaling in the embryo results in skin barrier defects accompanied by a B-lymphoproliferative disease. However, much less is known about the consequences of loss of Notch signaling after birth.

Methodology and principal findings: To study the function of Notch signaling in the skin of adult mice, we made use of a series of conditional gene targeted mice that allow inactivation of several components of the Notch signaling pathway specifically in the skin. We demonstrate that skin-specific inactivation of Notch1 and Notch2 simultaneously, or RBP-J, induces the development of a severe form of atopic dermatitis (AD), characterized by acanthosis, spongiosis and hyperkeratosis, as well as a massive dermal infiltration of eosinophils and mast cells. Likewise, patients suffering from AD, but not psoriasis or lichen planus, have a marked reduction of Notch receptor expression in the skin. Loss of Notch in keratinocytes induces the production of thymic stromal lymphopoietin (TSLP), a cytokine deeply implicated in the pathogenesis of AD. The AD-like associated inflammation is accompanied by a myeloproliferative disorder (MPD) characterized by an increase in immature myeloid populations in the bone marrow and spleen. Transplantation studies revealed that the MPD is cell non-autonomous and caused by dramatic microenvironmental alterations. Genetic studies demontrated that G-CSF mediates the MPD as well as changes in the bone marrow microenvironment leading to osteopenia.

Significance: Our data demonstrate a critical role for Notch in repressing TSLP production in keratinocytes, thereby maintaining integrity of the skin and the hematopoietic system.

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Related in: MedlinePlus

Notch signaling deficient epidermis massively produces TSLP.(A) qRT-PCR analysis of inflammatory cytokines on scraped epidermis of control (Ctrl, n = 3), N1N2K5 (n = 3) and RBP-JK5 (n = 3) mice (* p<0.01; ** p<0.001) showing relative increased expression of a wide panel of cytokines in mutant mice. TSLP shows the highest relative increase (125 fold) in mRNA among the tested cytokines. Three individual experiments were performed. (B) Serum TSLP levels in control (Ctrl, n = 4), N1N2K5 (n = 4) and RBP-JK5 (n = 4) mice revealing a 400 fold increase of this cytokine in mutant mice. The experiment was performed in triplicates. (C-D) Control (Ctrl) and N1N2K5 new born skin was grafted onto Athymic nu/nu mice and allowed to grow for 2 months (-Tamoxifen, n = 3). After induction of Cre-mediated recombination (+Tamoxifen, n = 3), the graft develops a similar phenotype to N1N2K5 mice. H/E and Toluidin blue staining shows acanthosis, hyperkeratosis, spongiosis, epidermoid cysts and massive infiltration of mast cells in the dermis of the N1N2K5 derived graft. Three individual experiments were performed. (E) TSLP serum levels of athymic nu/nu mice after grafting the skin of control (Ctrl) or N1N2K5 mice and subsequent gene inactivation. Serum from 3 Ctrl and 3 grafted Athymic nu/nu mice were pooled for the analysis. Bars represent the mean of two individual experiments.
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pone-0009258-g002: Notch signaling deficient epidermis massively produces TSLP.(A) qRT-PCR analysis of inflammatory cytokines on scraped epidermis of control (Ctrl, n = 3), N1N2K5 (n = 3) and RBP-JK5 (n = 3) mice (* p<0.01; ** p<0.001) showing relative increased expression of a wide panel of cytokines in mutant mice. TSLP shows the highest relative increase (125 fold) in mRNA among the tested cytokines. Three individual experiments were performed. (B) Serum TSLP levels in control (Ctrl, n = 4), N1N2K5 (n = 4) and RBP-JK5 (n = 4) mice revealing a 400 fold increase of this cytokine in mutant mice. The experiment was performed in triplicates. (C-D) Control (Ctrl) and N1N2K5 new born skin was grafted onto Athymic nu/nu mice and allowed to grow for 2 months (-Tamoxifen, n = 3). After induction of Cre-mediated recombination (+Tamoxifen, n = 3), the graft develops a similar phenotype to N1N2K5 mice. H/E and Toluidin blue staining shows acanthosis, hyperkeratosis, spongiosis, epidermoid cysts and massive infiltration of mast cells in the dermis of the N1N2K5 derived graft. Three individual experiments were performed. (E) TSLP serum levels of athymic nu/nu mice after grafting the skin of control (Ctrl) or N1N2K5 mice and subsequent gene inactivation. Serum from 3 Ctrl and 3 grafted Athymic nu/nu mice were pooled for the analysis. Bars represent the mean of two individual experiments.

Mentions: Consequently, we investigated more specifically the strong inflammatory response within the Notch deficient epidermis. For this purpose, we selectively isolated RNA from the epidermis of control, N1N2K5 and RBP-JK5 mice and conducted quantitative real-time PCR analysis for a panel of inflammatory cytokines, many of which were significantly increased (Figure 2A). These included TNFα (2.5 fold), IL-1β (28 fold) and IL-6 (27 fold), MCP1 (15 fold), MIP3α (43 fold), S100A8 (15 fold), S100A9 (56 fold), G-CSF (6 fold) and ICAM1 (3.5 fold). However, the cytokine TSLP showed the highest increase in relative amount (up to 125 fold), in both N1N2 and RBP-J deficient epidermis. Other Keratin 5-expressing tissues such as the thymic epithelium or bone marrow (BM) cells did not show increased TSLP expression (data not shown). Protein levels of TNFα and IL-1β were similar throughout the serum samples of mice investigated (data not shown). However, TSLP levels increased 400 fold in N1N2K5 and RBP-JK5 mice. They reached on average 4 to 7 ng/ml respectively (Figure 2B), suggesting that TSLP might be causative for the AD-like phenotype, as previously reported in humans and mice [22], [23], [24].


Atopic dermatitis-like disease and associated lethal myeloproliferative disorder arise from loss of Notch signaling in the murine skin.

Dumortier A, Durham AD, Di Piazza M, Vauclair S, Koch U, Ferrand G, Ferrero I, Demehri S, Song LL, Farr AG, Leonard WJ, Kopan R, Miele L, Hohl D, Finke D, Radtke F - PLoS ONE (2010)

Notch signaling deficient epidermis massively produces TSLP.(A) qRT-PCR analysis of inflammatory cytokines on scraped epidermis of control (Ctrl, n = 3), N1N2K5 (n = 3) and RBP-JK5 (n = 3) mice (* p<0.01; ** p<0.001) showing relative increased expression of a wide panel of cytokines in mutant mice. TSLP shows the highest relative increase (125 fold) in mRNA among the tested cytokines. Three individual experiments were performed. (B) Serum TSLP levels in control (Ctrl, n = 4), N1N2K5 (n = 4) and RBP-JK5 (n = 4) mice revealing a 400 fold increase of this cytokine in mutant mice. The experiment was performed in triplicates. (C-D) Control (Ctrl) and N1N2K5 new born skin was grafted onto Athymic nu/nu mice and allowed to grow for 2 months (-Tamoxifen, n = 3). After induction of Cre-mediated recombination (+Tamoxifen, n = 3), the graft develops a similar phenotype to N1N2K5 mice. H/E and Toluidin blue staining shows acanthosis, hyperkeratosis, spongiosis, epidermoid cysts and massive infiltration of mast cells in the dermis of the N1N2K5 derived graft. Three individual experiments were performed. (E) TSLP serum levels of athymic nu/nu mice after grafting the skin of control (Ctrl) or N1N2K5 mice and subsequent gene inactivation. Serum from 3 Ctrl and 3 grafted Athymic nu/nu mice were pooled for the analysis. Bars represent the mean of two individual experiments.
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Related In: Results  -  Collection

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pone-0009258-g002: Notch signaling deficient epidermis massively produces TSLP.(A) qRT-PCR analysis of inflammatory cytokines on scraped epidermis of control (Ctrl, n = 3), N1N2K5 (n = 3) and RBP-JK5 (n = 3) mice (* p<0.01; ** p<0.001) showing relative increased expression of a wide panel of cytokines in mutant mice. TSLP shows the highest relative increase (125 fold) in mRNA among the tested cytokines. Three individual experiments were performed. (B) Serum TSLP levels in control (Ctrl, n = 4), N1N2K5 (n = 4) and RBP-JK5 (n = 4) mice revealing a 400 fold increase of this cytokine in mutant mice. The experiment was performed in triplicates. (C-D) Control (Ctrl) and N1N2K5 new born skin was grafted onto Athymic nu/nu mice and allowed to grow for 2 months (-Tamoxifen, n = 3). After induction of Cre-mediated recombination (+Tamoxifen, n = 3), the graft develops a similar phenotype to N1N2K5 mice. H/E and Toluidin blue staining shows acanthosis, hyperkeratosis, spongiosis, epidermoid cysts and massive infiltration of mast cells in the dermis of the N1N2K5 derived graft. Three individual experiments were performed. (E) TSLP serum levels of athymic nu/nu mice after grafting the skin of control (Ctrl) or N1N2K5 mice and subsequent gene inactivation. Serum from 3 Ctrl and 3 grafted Athymic nu/nu mice were pooled for the analysis. Bars represent the mean of two individual experiments.
Mentions: Consequently, we investigated more specifically the strong inflammatory response within the Notch deficient epidermis. For this purpose, we selectively isolated RNA from the epidermis of control, N1N2K5 and RBP-JK5 mice and conducted quantitative real-time PCR analysis for a panel of inflammatory cytokines, many of which were significantly increased (Figure 2A). These included TNFα (2.5 fold), IL-1β (28 fold) and IL-6 (27 fold), MCP1 (15 fold), MIP3α (43 fold), S100A8 (15 fold), S100A9 (56 fold), G-CSF (6 fold) and ICAM1 (3.5 fold). However, the cytokine TSLP showed the highest increase in relative amount (up to 125 fold), in both N1N2 and RBP-J deficient epidermis. Other Keratin 5-expressing tissues such as the thymic epithelium or bone marrow (BM) cells did not show increased TSLP expression (data not shown). Protein levels of TNFα and IL-1β were similar throughout the serum samples of mice investigated (data not shown). However, TSLP levels increased 400 fold in N1N2K5 and RBP-JK5 mice. They reached on average 4 to 7 ng/ml respectively (Figure 2B), suggesting that TSLP might be causative for the AD-like phenotype, as previously reported in humans and mice [22], [23], [24].

Bottom Line: The AD-like associated inflammation is accompanied by a myeloproliferative disorder (MPD) characterized by an increase in immature myeloid populations in the bone marrow and spleen.Genetic studies demontrated that G-CSF mediates the MPD as well as changes in the bone marrow microenvironment leading to osteopenia.Our data demonstrate a critical role for Notch in repressing TSLP production in keratinocytes, thereby maintaining integrity of the skin and the hematopoietic system.

View Article: PubMed Central - PubMed

Affiliation: Ecole Polytechnique Fédérale de Lausanne (EPFL SV ISREC), Lausanne, Switzerland.

ABSTRACT

Background: The Notch pathway is essential for proper epidermal differentiation during embryonic skin development. Moreover, skin specific loss of Notch signaling in the embryo results in skin barrier defects accompanied by a B-lymphoproliferative disease. However, much less is known about the consequences of loss of Notch signaling after birth.

Methodology and principal findings: To study the function of Notch signaling in the skin of adult mice, we made use of a series of conditional gene targeted mice that allow inactivation of several components of the Notch signaling pathway specifically in the skin. We demonstrate that skin-specific inactivation of Notch1 and Notch2 simultaneously, or RBP-J, induces the development of a severe form of atopic dermatitis (AD), characterized by acanthosis, spongiosis and hyperkeratosis, as well as a massive dermal infiltration of eosinophils and mast cells. Likewise, patients suffering from AD, but not psoriasis or lichen planus, have a marked reduction of Notch receptor expression in the skin. Loss of Notch in keratinocytes induces the production of thymic stromal lymphopoietin (TSLP), a cytokine deeply implicated in the pathogenesis of AD. The AD-like associated inflammation is accompanied by a myeloproliferative disorder (MPD) characterized by an increase in immature myeloid populations in the bone marrow and spleen. Transplantation studies revealed that the MPD is cell non-autonomous and caused by dramatic microenvironmental alterations. Genetic studies demontrated that G-CSF mediates the MPD as well as changes in the bone marrow microenvironment leading to osteopenia.

Significance: Our data demonstrate a critical role for Notch in repressing TSLP production in keratinocytes, thereby maintaining integrity of the skin and the hematopoietic system.

Show MeSH
Related in: MedlinePlus