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Desmoglein 1-dependent suppression of EGFR signaling promotes epidermal differentiation and morphogenesis.

Getsios S, Simpson CL, Kojima S, Harmon R, Sheu LJ, Dusek RL, Cornwell M, Green KJ - J. Cell Biol. (2009)

Bottom Line: Moreover, this capability did not depend on cytodomain interactions with the armadillo protein plakoglobin or coexpression of its companion suprabasal cadherin, Dsc1 (desmocollin 1).Instead, Dsg1 was required for suppression of epidermal growth factor receptor-Erk1/2 (extracellular signal-regulated kinase 1/2) signaling, thereby facilitating keratinocyte progression through a terminal differentiation program.In addition to serving as a rigid anchor between adjacent cells, this study implicates desmosomal cadherins as key components of a signaling axis governing epithelial morphogenesis.

View Article: PubMed Central - PubMed

Affiliation: Department of Pathology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA.

ABSTRACT
Dsg1 (desmoglein 1) is a member of the cadherin family of Ca(2+)-dependent cell adhesion molecules that is first expressed in the epidermis as keratinocytes transit out of the basal layer and becomes concentrated in the uppermost cell layers of this stratified epithelium. In this study, we show that Dsg1 is not only required for maintaining epidermal tissue integrity in the superficial layers but also supports keratinocyte differentiation and suprabasal morphogenesis. Dsg1 lacking N-terminal ectodomain residues required for adhesion remained capable of promoting keratinocyte differentiation. Moreover, this capability did not depend on cytodomain interactions with the armadillo protein plakoglobin or coexpression of its companion suprabasal cadherin, Dsc1 (desmocollin 1). Instead, Dsg1 was required for suppression of epidermal growth factor receptor-Erk1/2 (extracellular signal-regulated kinase 1/2) signaling, thereby facilitating keratinocyte progression through a terminal differentiation program. In addition to serving as a rigid anchor between adjacent cells, this study implicates desmosomal cadherins as key components of a signaling axis governing epithelial morphogenesis.

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Dsg1 deficiency impairs morphogenesis of epidermal raft cultures. (A) H&E-stained sections of 6-d-old rafts expressing miR Lmn or miR DG1. Dsg1-deficient rafts exhibited abnormal suprabasal morphology (insets with continuous lines) and a poorly differentiated appearance (insets with dashed lines) compared with controls. (B) IHC analysis of Dsg1 in miR Lmn or miR DG1 rafts revealed a profound loss of Dsg1 at 6 d. The keratinocyte–collagen interface is highlighted by the dotted line. (C) Western blot analysis of Dsg1, Dsg3, lamin A/C (Lmn A/C), and GAPDH (glyceraldehyde-3-phosphate dehydrogenase) from these raft cultures indicated that Dsg1 or lamin A/C levels were reduced by ∼90%. (D) An actin antibody was used to highlight the cellular cortex in Dsg1-deficient cultures and generate surface area measurements of individual suprabasal cells using indirect immunofluorescence staining. Although control cultures exhibited compact, uniformly shaped suprabasal cells, cultures lacking Dsg1 possessed suprabasal cells that displayed a highly irregular array of individual cell sizes. Boxed insets highlight suprabasal cell morphology between miR Lmn and miR DG1 rafts. (E) The surface area from individual suprabasal cells (n > 150) from miR Lmn or miR DG1 rafts was measured using MetaMorph software, and individual data points from a representative experiment are shown in the scatter plot. Bars: (A, B, and D) 50 µm; (insets) 20 µm.
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fig2: Dsg1 deficiency impairs morphogenesis of epidermal raft cultures. (A) H&E-stained sections of 6-d-old rafts expressing miR Lmn or miR DG1. Dsg1-deficient rafts exhibited abnormal suprabasal morphology (insets with continuous lines) and a poorly differentiated appearance (insets with dashed lines) compared with controls. (B) IHC analysis of Dsg1 in miR Lmn or miR DG1 rafts revealed a profound loss of Dsg1 at 6 d. The keratinocyte–collagen interface is highlighted by the dotted line. (C) Western blot analysis of Dsg1, Dsg3, lamin A/C (Lmn A/C), and GAPDH (glyceraldehyde-3-phosphate dehydrogenase) from these raft cultures indicated that Dsg1 or lamin A/C levels were reduced by ∼90%. (D) An actin antibody was used to highlight the cellular cortex in Dsg1-deficient cultures and generate surface area measurements of individual suprabasal cells using indirect immunofluorescence staining. Although control cultures exhibited compact, uniformly shaped suprabasal cells, cultures lacking Dsg1 possessed suprabasal cells that displayed a highly irregular array of individual cell sizes. Boxed insets highlight suprabasal cell morphology between miR Lmn and miR DG1 rafts. (E) The surface area from individual suprabasal cells (n > 150) from miR Lmn or miR DG1 rafts was measured using MetaMorph software, and individual data points from a representative experiment are shown in the scatter plot. Bars: (A, B, and D) 50 µm; (insets) 20 µm.

Mentions: Dsg1 was commonly detected at the interface between basal and suprabasal keratinocytes (Fig. 1 A), leading us to posit that this desmosomal cadherin might play an early instructive role as epidermal cells commit to a differentiation program. To address this possibility, we silenced Dsg1 expression in raft cultures using retroviruses engineered to express microRNA (miRNA)-like sequences specific for this desmosomal cadherin (miR DG1) or lamin A/C (miR Lmn) as a control. Unlike lamin A/C–silenced rafts, there was a marked disorganization in the suprabasal layers that formed in Dsg1-deficient cultures (Fig. 2, A–C). In comparison with controls, we noted widened intercellular spaces (Fig. S3), irregular cell shapes in the intermediate layers (Fig. 2, D and E), and an immature granular layer suggestive of impaired differentiation (Fig. 2 A). Expression of a companion suprabasal cadherin, Dsc1, was markedly reduced; in contrast, the levels of classical and other desmosomal cadherins present in the lower layers were only marginally affected by the loss of Dsg1 and remained prominent at areas of cell–cell contact (Fig. S1).


Desmoglein 1-dependent suppression of EGFR signaling promotes epidermal differentiation and morphogenesis.

Getsios S, Simpson CL, Kojima S, Harmon R, Sheu LJ, Dusek RL, Cornwell M, Green KJ - J. Cell Biol. (2009)

Dsg1 deficiency impairs morphogenesis of epidermal raft cultures. (A) H&E-stained sections of 6-d-old rafts expressing miR Lmn or miR DG1. Dsg1-deficient rafts exhibited abnormal suprabasal morphology (insets with continuous lines) and a poorly differentiated appearance (insets with dashed lines) compared with controls. (B) IHC analysis of Dsg1 in miR Lmn or miR DG1 rafts revealed a profound loss of Dsg1 at 6 d. The keratinocyte–collagen interface is highlighted by the dotted line. (C) Western blot analysis of Dsg1, Dsg3, lamin A/C (Lmn A/C), and GAPDH (glyceraldehyde-3-phosphate dehydrogenase) from these raft cultures indicated that Dsg1 or lamin A/C levels were reduced by ∼90%. (D) An actin antibody was used to highlight the cellular cortex in Dsg1-deficient cultures and generate surface area measurements of individual suprabasal cells using indirect immunofluorescence staining. Although control cultures exhibited compact, uniformly shaped suprabasal cells, cultures lacking Dsg1 possessed suprabasal cells that displayed a highly irregular array of individual cell sizes. Boxed insets highlight suprabasal cell morphology between miR Lmn and miR DG1 rafts. (E) The surface area from individual suprabasal cells (n > 150) from miR Lmn or miR DG1 rafts was measured using MetaMorph software, and individual data points from a representative experiment are shown in the scatter plot. Bars: (A, B, and D) 50 µm; (insets) 20 µm.
© Copyright Policy - openaccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC2712955&req=5

fig2: Dsg1 deficiency impairs morphogenesis of epidermal raft cultures. (A) H&E-stained sections of 6-d-old rafts expressing miR Lmn or miR DG1. Dsg1-deficient rafts exhibited abnormal suprabasal morphology (insets with continuous lines) and a poorly differentiated appearance (insets with dashed lines) compared with controls. (B) IHC analysis of Dsg1 in miR Lmn or miR DG1 rafts revealed a profound loss of Dsg1 at 6 d. The keratinocyte–collagen interface is highlighted by the dotted line. (C) Western blot analysis of Dsg1, Dsg3, lamin A/C (Lmn A/C), and GAPDH (glyceraldehyde-3-phosphate dehydrogenase) from these raft cultures indicated that Dsg1 or lamin A/C levels were reduced by ∼90%. (D) An actin antibody was used to highlight the cellular cortex in Dsg1-deficient cultures and generate surface area measurements of individual suprabasal cells using indirect immunofluorescence staining. Although control cultures exhibited compact, uniformly shaped suprabasal cells, cultures lacking Dsg1 possessed suprabasal cells that displayed a highly irregular array of individual cell sizes. Boxed insets highlight suprabasal cell morphology between miR Lmn and miR DG1 rafts. (E) The surface area from individual suprabasal cells (n > 150) from miR Lmn or miR DG1 rafts was measured using MetaMorph software, and individual data points from a representative experiment are shown in the scatter plot. Bars: (A, B, and D) 50 µm; (insets) 20 µm.
Mentions: Dsg1 was commonly detected at the interface between basal and suprabasal keratinocytes (Fig. 1 A), leading us to posit that this desmosomal cadherin might play an early instructive role as epidermal cells commit to a differentiation program. To address this possibility, we silenced Dsg1 expression in raft cultures using retroviruses engineered to express microRNA (miRNA)-like sequences specific for this desmosomal cadherin (miR DG1) or lamin A/C (miR Lmn) as a control. Unlike lamin A/C–silenced rafts, there was a marked disorganization in the suprabasal layers that formed in Dsg1-deficient cultures (Fig. 2, A–C). In comparison with controls, we noted widened intercellular spaces (Fig. S3), irregular cell shapes in the intermediate layers (Fig. 2, D and E), and an immature granular layer suggestive of impaired differentiation (Fig. 2 A). Expression of a companion suprabasal cadherin, Dsc1, was markedly reduced; in contrast, the levels of classical and other desmosomal cadherins present in the lower layers were only marginally affected by the loss of Dsg1 and remained prominent at areas of cell–cell contact (Fig. S1).

Bottom Line: Moreover, this capability did not depend on cytodomain interactions with the armadillo protein plakoglobin or coexpression of its companion suprabasal cadherin, Dsc1 (desmocollin 1).Instead, Dsg1 was required for suppression of epidermal growth factor receptor-Erk1/2 (extracellular signal-regulated kinase 1/2) signaling, thereby facilitating keratinocyte progression through a terminal differentiation program.In addition to serving as a rigid anchor between adjacent cells, this study implicates desmosomal cadherins as key components of a signaling axis governing epithelial morphogenesis.

View Article: PubMed Central - PubMed

Affiliation: Department of Pathology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA.

ABSTRACT
Dsg1 (desmoglein 1) is a member of the cadherin family of Ca(2+)-dependent cell adhesion molecules that is first expressed in the epidermis as keratinocytes transit out of the basal layer and becomes concentrated in the uppermost cell layers of this stratified epithelium. In this study, we show that Dsg1 is not only required for maintaining epidermal tissue integrity in the superficial layers but also supports keratinocyte differentiation and suprabasal morphogenesis. Dsg1 lacking N-terminal ectodomain residues required for adhesion remained capable of promoting keratinocyte differentiation. Moreover, this capability did not depend on cytodomain interactions with the armadillo protein plakoglobin or coexpression of its companion suprabasal cadherin, Dsc1 (desmocollin 1). Instead, Dsg1 was required for suppression of epidermal growth factor receptor-Erk1/2 (extracellular signal-regulated kinase 1/2) signaling, thereby facilitating keratinocyte progression through a terminal differentiation program. In addition to serving as a rigid anchor between adjacent cells, this study implicates desmosomal cadherins as key components of a signaling axis governing epithelial morphogenesis.

Show MeSH
Related in: MedlinePlus