Lack of nidogen-1 and -2 prevents basement membrane assembly in skin-organotypic coculture.
Nidogens are considered as classical linkers joining laminin and collagen IV networks in basement membranes (BMs); however, recent genetic approaches have suggested that nidogens function in a tissue-specific and developmental context. Thus, in mice lacking both nidogen-1 and -2 heart and lung were severely affected, causing neonatal death. Furthermore, in various locations, extravasation of erythrocytes was observed implying microvascular defects. Mice expressing solely either isoform, had a functional BM, although nidogen-2 binds with lower affinity to the laminin gamma1 chain. Having previously blocked BM formation by interfering with nidogen-1 binding to laminin in skin-organotypic cocultures, here we investigated the roles of nidogen-1 and -2 in this model. For that purpose, human HaCaT cells were grown in three-dimensional cocultures on collagen matrices containing murine fibroblasts of varying nidogen deficiency. As with our experiments blocking laminin-nidogen interaction, lack of both nidogens completely prevented BM deposition and ultrastructural assembly of BM and hemidesmosomes, although other BM proteins remained detectable at comparable levels with no signs of degradation. Supplementation by recombinant nidogen-1 or -2 restored these structures, as shown by immunofluorescence and electron microscopy, confirming that in this system nidogen-2 is equivalent to nidogen-1, and both can promote the development of a functional BM zone.
Nischt
Roswitha
R
Department of Dermatology, University of Cologne, Cologne, Germany.
Schmidt
Cathrine
C
Mirancea
Nicolae
N
Baranowsky
Anke
A
Mokkapati
Sharada
S
Smyth
Neil
N
Woenne
Eva C
EC
Stark
Hans-Jürgen
HJ
Boukamp
Petra
P
Breitkreutz
Dirk
D
D000818:Animals; D001485:Basement Membrane / Q000378:metabolism*; D002135:Calcium-Binding Proteins; D015815:Cell Adhesion Molecules / Q000096:biosynthesis / Q000502:physiology*; D018920:Coculture Techniques; D003094:Collagen / Q000737:chemistry; D020405:Dermis / Q000378:metabolism; D004817:Epidermis / Q000378:metabolism; D004912:Erythrocytes / Q000378:metabolism; D005347:Fibroblasts / Q000378:metabolism; D006801:Humans; D008562:Membrane Glycoproteins / Q000096:biosynthesis / Q000502:physiology*; D051379:Mice; D009924:Organ Culture Techniques; D020033:Protein Isoforms; D012867:Skin / Q000276:immunology*
D002135:Calcium-Binding Proteins; D015815:Cell Adhesion Molecules; D008562:Membrane Glycoproteins; C114729:NID2 protein, human; D020033:Protein Isoforms; C029967:nidogen; D003094:Collagen