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alpha3beta1 Integrin is required for normal development of the epidermal basement membrane.

DiPersio CM, Hodivala-Dilke KM, Jaenisch R, Kreidberg JA, Hynes RO - J. Cell Biol. (1997)

Bottom Line: Laminin-5 and other matrix proteins remained associated with both the dermal and epidermal sides of blisters, suggesting rupture of the basement membrane itself, rather than detachment of the epidermis from the basement membrane as occurs in some blistering disorders such as epidermolysis bullosa.Consistent with this notion, primary keratinocytes from alpha3beta1-deficient skin adhered to laminin-5 through alpha6 integrins.However, alpha3beta1-deficient keratinocytes spread poorly compared with wild-type cells on laminin-5, demonstrating a postattachment requirement for alpha3beta1 and indicating distinct roles for alpha3beta1 and alpha6beta4.

View Article: PubMed Central - PubMed

Affiliation: Center for Cancer Research, and Department of Biology, Massachusetts Institute of Technology, Cambridge 02139, USA.

ABSTRACT
Integrins alpha3beta1 and alpha6beta4 are abundant receptors on keratinocytes for laminin-5, a major component of the basement membrane between the epidermis and the dermis in skin. These integrins are recruited to distinct adhesion structures within keratinocytes; alpha6beta4 is present in hemidesmosomes, while alpha3beta1 is recruited into focal contacts in cultured cells. To determine whether differences in localization reflect distinct functions of these integrins in the epidermis, we studied skin development in alpha3beta1-deficient mice. Examination of extracellular matrix by immunofluorescence microscopy and electron microscopy revealed regions of disorganized basement membrane in alpha3beta1-deficient skin. Disorganized matrix was first detected by day 15.5 of embryonic development and became progressively more extensive as development proceeded. In neonatal skin, matrix disorganization was frequently accompanied by blistering at the dermal-epidermal junction. Laminin-5 and other matrix proteins remained associated with both the dermal and epidermal sides of blisters, suggesting rupture of the basement membrane itself, rather than detachment of the epidermis from the basement membrane as occurs in some blistering disorders such as epidermolysis bullosa. Consistent with this notion, primary keratinocytes from alpha3beta1-deficient skin adhered to laminin-5 through alpha6 integrins. However, alpha3beta1-deficient keratinocytes spread poorly compared with wild-type cells on laminin-5, demonstrating a postattachment requirement for alpha3beta1 and indicating distinct roles for alpha3beta1 and alpha6beta4. Our findings support a novel role for alpha3beta1 in establishment and/or maintenance of basement membrane integrity, while alpha6beta4 is required for stable adhesion of the epidermis to the basement membrane through hemidesmosomes.

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α3- mice form  skin blisters. (A and B) Frozen skin sections from wildtype (A) or α3- (B) mice  were stained with hematoxylin and eosin and the epidermal-dermal junctions were  compared. Arrowheads point  to basal keratinocytes of the  epidermis. (C and D) A frozen skin section from an α3 mouse showing a blister  viewed by phase contrast  (C) or stained by immunofluorescence with an antiserum  against laminin-5 (D). Arrowheads and arrows point  to areas of laminin-5 staining  at the dermal and epidermal  sides of the blister, respectively. e, epidermis; d, dermis. Bars, 50 μm.
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Figure 2: α3- mice form skin blisters. (A and B) Frozen skin sections from wildtype (A) or α3- (B) mice were stained with hematoxylin and eosin and the epidermal-dermal junctions were compared. Arrowheads point to basal keratinocytes of the epidermis. (C and D) A frozen skin section from an α3 mouse showing a blister viewed by phase contrast (C) or stained by immunofluorescence with an antiserum against laminin-5 (D). Arrowheads and arrows point to areas of laminin-5 staining at the dermal and epidermal sides of the blister, respectively. e, epidermis; d, dermis. Bars, 50 μm.

Mentions: Frozen sections were prepared from the limbs of α3- or wild-type mice and stained by immunofluorescence with an antiserum against the cytoplasmic domain of the α3 subunit (DiPersio et al., 1995). In wild-type mice, α3 expression was restricted to the basal layer of keratinocytes in the epidermis (Fig. 1, A and B, arrows), as expected for this integrin (Peltonen et al., 1989; Carter et al., 1990a,b; Hertle et al., 1991). Preimmune serum did not stain the epidermis (Fig. 1, C and D). In α3- mice, stratification of the epidermis appeared normal (Figs. 1 E and 2 B). However, staining of the basal keratinocytes of α3- epidermis with anti-α3 (Fig. 1 F, arrow) was comparable to background staining with preimmune serum (Figs. 1, G and H). The absence of α3β1 from α3- skin was confirmed by Western blotting (data not shown). α3 staining intensity of basal keratinocytes in mice that were heterozygous for the α3 mutation was intermediate (data not shown).


alpha3beta1 Integrin is required for normal development of the epidermal basement membrane.

DiPersio CM, Hodivala-Dilke KM, Jaenisch R, Kreidberg JA, Hynes RO - J. Cell Biol. (1997)

α3- mice form  skin blisters. (A and B) Frozen skin sections from wildtype (A) or α3- (B) mice  were stained with hematoxylin and eosin and the epidermal-dermal junctions were  compared. Arrowheads point  to basal keratinocytes of the  epidermis. (C and D) A frozen skin section from an α3 mouse showing a blister  viewed by phase contrast  (C) or stained by immunofluorescence with an antiserum  against laminin-5 (D). Arrowheads and arrows point  to areas of laminin-5 staining  at the dermal and epidermal  sides of the blister, respectively. e, epidermis; d, dermis. Bars, 50 μm.
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Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2139886&req=5

Figure 2: α3- mice form skin blisters. (A and B) Frozen skin sections from wildtype (A) or α3- (B) mice were stained with hematoxylin and eosin and the epidermal-dermal junctions were compared. Arrowheads point to basal keratinocytes of the epidermis. (C and D) A frozen skin section from an α3 mouse showing a blister viewed by phase contrast (C) or stained by immunofluorescence with an antiserum against laminin-5 (D). Arrowheads and arrows point to areas of laminin-5 staining at the dermal and epidermal sides of the blister, respectively. e, epidermis; d, dermis. Bars, 50 μm.
Mentions: Frozen sections were prepared from the limbs of α3- or wild-type mice and stained by immunofluorescence with an antiserum against the cytoplasmic domain of the α3 subunit (DiPersio et al., 1995). In wild-type mice, α3 expression was restricted to the basal layer of keratinocytes in the epidermis (Fig. 1, A and B, arrows), as expected for this integrin (Peltonen et al., 1989; Carter et al., 1990a,b; Hertle et al., 1991). Preimmune serum did not stain the epidermis (Fig. 1, C and D). In α3- mice, stratification of the epidermis appeared normal (Figs. 1 E and 2 B). However, staining of the basal keratinocytes of α3- epidermis with anti-α3 (Fig. 1 F, arrow) was comparable to background staining with preimmune serum (Figs. 1, G and H). The absence of α3β1 from α3- skin was confirmed by Western blotting (data not shown). α3 staining intensity of basal keratinocytes in mice that were heterozygous for the α3 mutation was intermediate (data not shown).

Bottom Line: Laminin-5 and other matrix proteins remained associated with both the dermal and epidermal sides of blisters, suggesting rupture of the basement membrane itself, rather than detachment of the epidermis from the basement membrane as occurs in some blistering disorders such as epidermolysis bullosa.Consistent with this notion, primary keratinocytes from alpha3beta1-deficient skin adhered to laminin-5 through alpha6 integrins.However, alpha3beta1-deficient keratinocytes spread poorly compared with wild-type cells on laminin-5, demonstrating a postattachment requirement for alpha3beta1 and indicating distinct roles for alpha3beta1 and alpha6beta4.

View Article: PubMed Central - PubMed

Affiliation: Center for Cancer Research, and Department of Biology, Massachusetts Institute of Technology, Cambridge 02139, USA.

ABSTRACT
Integrins alpha3beta1 and alpha6beta4 are abundant receptors on keratinocytes for laminin-5, a major component of the basement membrane between the epidermis and the dermis in skin. These integrins are recruited to distinct adhesion structures within keratinocytes; alpha6beta4 is present in hemidesmosomes, while alpha3beta1 is recruited into focal contacts in cultured cells. To determine whether differences in localization reflect distinct functions of these integrins in the epidermis, we studied skin development in alpha3beta1-deficient mice. Examination of extracellular matrix by immunofluorescence microscopy and electron microscopy revealed regions of disorganized basement membrane in alpha3beta1-deficient skin. Disorganized matrix was first detected by day 15.5 of embryonic development and became progressively more extensive as development proceeded. In neonatal skin, matrix disorganization was frequently accompanied by blistering at the dermal-epidermal junction. Laminin-5 and other matrix proteins remained associated with both the dermal and epidermal sides of blisters, suggesting rupture of the basement membrane itself, rather than detachment of the epidermis from the basement membrane as occurs in some blistering disorders such as epidermolysis bullosa. Consistent with this notion, primary keratinocytes from alpha3beta1-deficient skin adhered to laminin-5 through alpha6 integrins. However, alpha3beta1-deficient keratinocytes spread poorly compared with wild-type cells on laminin-5, demonstrating a postattachment requirement for alpha3beta1 and indicating distinct roles for alpha3beta1 and alpha6beta4. Our findings support a novel role for alpha3beta1 in establishment and/or maintenance of basement membrane integrity, while alpha6beta4 is required for stable adhesion of the epidermis to the basement membrane through hemidesmosomes.

Show MeSH
Related in: MedlinePlus