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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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Related in: MedlinePlus

N-terminal ectodomain residues of Dsg1 required for adhesion are not essential for epidermal raft development. (A) H&E analysis of raft cultures treated with WT ETA (ETA WT) or a protease-dead mutant (ETA mut) and maintained at an air–liquid interface for an additional 6 d. Chronic Dsg1 EC1–3 cleavage did not grossly alter suprabasal morphogenesis. (B) Western blot analysis revealed a reduction in Dsc1, K10, filaggrin, and loricrin in raft cultures deficient in Dsg1 (miR DG1) compared with miR Lmn controls. In contrast, there were no differences in the levels of these suprabasal proteins in rafts treated with ETA WT or mut. Levels of Dsg3 and the basal marker K14 were equivalent in all conditions. Black lines indicate that intervening lanes have been spliced out. CL, cleaved; FL, full length; GAPDH, glyceraldehyde-3-phosphate dehydrogenase. (C) IHC staining confirmed that both K10 and Dsc1 (Figs. S1 and S4) were reduced in Dsg1-silenced cultures (miR DG1), whereas control (miR Lmn) and ETA-treated (ETA WT) cultures robustly expressed these suprabasal markers. Also, note that ETA-treated cultures retained a cleaved fragment (aa 382–1,049) of Dsg1 at intercellular borders, as revealed by staining with an antibody against the cytoplasmic domain of Dsg1 (Dsg1 cyto), whereas the extracellular epitope (aa 1–381) was effectively removed by ETA (inset). The dotted lines indicate the boundary between keratinocytes and the collagen matrix. (D) The mean surface area (±SEM) of individual suprabasal cells from ETA-treated or Dsg1 knockdown rafts was determined using actin immunostaining to outline the cell cortex. Although control and ETA-treated cultures exhibited suprabasal cells of similar size, cultures lacking Dsg1 possessed suprabasal cells that were nearly twice as large. Bars, 50 µm.
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fig3: N-terminal ectodomain residues of Dsg1 required for adhesion are not essential for epidermal raft development. (A) H&E analysis of raft cultures treated with WT ETA (ETA WT) or a protease-dead mutant (ETA mut) and maintained at an air–liquid interface for an additional 6 d. Chronic Dsg1 EC1–3 cleavage did not grossly alter suprabasal morphogenesis. (B) Western blot analysis revealed a reduction in Dsc1, K10, filaggrin, and loricrin in raft cultures deficient in Dsg1 (miR DG1) compared with miR Lmn controls. In contrast, there were no differences in the levels of these suprabasal proteins in rafts treated with ETA WT or mut. Levels of Dsg3 and the basal marker K14 were equivalent in all conditions. Black lines indicate that intervening lanes have been spliced out. CL, cleaved; FL, full length; GAPDH, glyceraldehyde-3-phosphate dehydrogenase. (C) IHC staining confirmed that both K10 and Dsc1 (Figs. S1 and S4) were reduced in Dsg1-silenced cultures (miR DG1), whereas control (miR Lmn) and ETA-treated (ETA WT) cultures robustly expressed these suprabasal markers. Also, note that ETA-treated cultures retained a cleaved fragment (aa 382–1,049) of Dsg1 at intercellular borders, as revealed by staining with an antibody against the cytoplasmic domain of Dsg1 (Dsg1 cyto), whereas the extracellular epitope (aa 1–381) was effectively removed by ETA (inset). The dotted lines indicate the boundary between keratinocytes and the collagen matrix. (D) The mean surface area (±SEM) of individual suprabasal cells from ETA-treated or Dsg1 knockdown rafts was determined using actin immunostaining to outline the cell cortex. Although control and ETA-treated cultures exhibited suprabasal cells of similar size, cultures lacking Dsg1 possessed suprabasal cells that were nearly twice as large. Bars, 50 µm.

Mentions: To determine whether the aberrant morphology of stratifying keratinocytes in Dsg1-deficient cultures was accompanied by alterations in the differentiation program, we investigated the expression of several well-characterized structural proteins that are induced upon keratinocyte differentiation. Consistent with the histological analysis, rafts lacking Dsg1 exhibited a marked reduction in both early (Dsc1 and keratin 10 [K10]) and late markers (loricrin and processed filaggrin) of epidermal differentiation (Fig. 3, B and C). In addition, proliferation, as assessed by Ki67 staining and BrdU incorporation (Fig. S2), and the expression of proteins more prominent in the basal layer such as K14 remained unchanged in Dsg1-deficient cultures.


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)

N-terminal ectodomain residues of Dsg1 required for adhesion are not essential for epidermal raft development. (A) H&E analysis of raft cultures treated with WT ETA (ETA WT) or a protease-dead mutant (ETA mut) and maintained at an air–liquid interface for an additional 6 d. Chronic Dsg1 EC1–3 cleavage did not grossly alter suprabasal morphogenesis. (B) Western blot analysis revealed a reduction in Dsc1, K10, filaggrin, and loricrin in raft cultures deficient in Dsg1 (miR DG1) compared with miR Lmn controls. In contrast, there were no differences in the levels of these suprabasal proteins in rafts treated with ETA WT or mut. Levels of Dsg3 and the basal marker K14 were equivalent in all conditions. Black lines indicate that intervening lanes have been spliced out. CL, cleaved; FL, full length; GAPDH, glyceraldehyde-3-phosphate dehydrogenase. (C) IHC staining confirmed that both K10 and Dsc1 (Figs. S1 and S4) were reduced in Dsg1-silenced cultures (miR DG1), whereas control (miR Lmn) and ETA-treated (ETA WT) cultures robustly expressed these suprabasal markers. Also, note that ETA-treated cultures retained a cleaved fragment (aa 382–1,049) of Dsg1 at intercellular borders, as revealed by staining with an antibody against the cytoplasmic domain of Dsg1 (Dsg1 cyto), whereas the extracellular epitope (aa 1–381) was effectively removed by ETA (inset). The dotted lines indicate the boundary between keratinocytes and the collagen matrix. (D) The mean surface area (±SEM) of individual suprabasal cells from ETA-treated or Dsg1 knockdown rafts was determined using actin immunostaining to outline the cell cortex. Although control and ETA-treated cultures exhibited suprabasal cells of similar size, cultures lacking Dsg1 possessed suprabasal cells that were nearly twice as large. Bars, 50 µm.
© Copyright Policy - openaccess
Related In: Results  -  Collection

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

fig3: N-terminal ectodomain residues of Dsg1 required for adhesion are not essential for epidermal raft development. (A) H&E analysis of raft cultures treated with WT ETA (ETA WT) or a protease-dead mutant (ETA mut) and maintained at an air–liquid interface for an additional 6 d. Chronic Dsg1 EC1–3 cleavage did not grossly alter suprabasal morphogenesis. (B) Western blot analysis revealed a reduction in Dsc1, K10, filaggrin, and loricrin in raft cultures deficient in Dsg1 (miR DG1) compared with miR Lmn controls. In contrast, there were no differences in the levels of these suprabasal proteins in rafts treated with ETA WT or mut. Levels of Dsg3 and the basal marker K14 were equivalent in all conditions. Black lines indicate that intervening lanes have been spliced out. CL, cleaved; FL, full length; GAPDH, glyceraldehyde-3-phosphate dehydrogenase. (C) IHC staining confirmed that both K10 and Dsc1 (Figs. S1 and S4) were reduced in Dsg1-silenced cultures (miR DG1), whereas control (miR Lmn) and ETA-treated (ETA WT) cultures robustly expressed these suprabasal markers. Also, note that ETA-treated cultures retained a cleaved fragment (aa 382–1,049) of Dsg1 at intercellular borders, as revealed by staining with an antibody against the cytoplasmic domain of Dsg1 (Dsg1 cyto), whereas the extracellular epitope (aa 1–381) was effectively removed by ETA (inset). The dotted lines indicate the boundary between keratinocytes and the collagen matrix. (D) The mean surface area (±SEM) of individual suprabasal cells from ETA-treated or Dsg1 knockdown rafts was determined using actin immunostaining to outline the cell cortex. Although control and ETA-treated cultures exhibited suprabasal cells of similar size, cultures lacking Dsg1 possessed suprabasal cells that were nearly twice as large. Bars, 50 µm.
Mentions: To determine whether the aberrant morphology of stratifying keratinocytes in Dsg1-deficient cultures was accompanied by alterations in the differentiation program, we investigated the expression of several well-characterized structural proteins that are induced upon keratinocyte differentiation. Consistent with the histological analysis, rafts lacking Dsg1 exhibited a marked reduction in both early (Dsc1 and keratin 10 [K10]) and late markers (loricrin and processed filaggrin) of epidermal differentiation (Fig. 3, B and C). In addition, proliferation, as assessed by Ki67 staining and BrdU incorporation (Fig. S2), and the expression of proteins more prominent in the basal layer such as K14 remained unchanged in Dsg1-deficient cultures.

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