title: RhoA activation by CNFy restores cell-cell adhesion in kindlin-2-deficient keratinocytes.
abstract: Kindlins are a family of integrin adapter and cell-matrix adhesion proteins causally linked to human genetic disorders. Kindlin-2 is a ubiquitously expressed protein with manifold functions and interactions. The contribution of kindlin-2 to integrin-based cell-matrix adhesions has been extensively explored, while other integrin-independent roles emerge. Because of the early involvement of kindlin-2 in development, no viable animal models with its constitutional knockout are available to study its physiological functions in adult skin. Here, we uncovered a critical physiological role of kindlin-2 in the epidermis by using a skin-equivalent model with shRNA-mediated knock-down of kindlin-2 in keratinocytes. Kindlin-2-deficient keratinocytes built stratified epidermal layers, but displayed impaired dermal-epidermal and intra-epidermal adhesion and barrier function. Co-immunoprecipitation studies demonstrated that kindlin-2 interacts with both integrin- and cadherin-based adhesions. In kindlin-2-deficient keratinocytes, reduced cell-cell adhesion was associated with abnormal cytoplasmic distribution of adherens junctions and desmosomal proteins, which was dependent on RhoA activation. Direct activation of RhoA with recombinant bacterial cytotoxic necrotizing factor y (CNFy) reverted the abnormal phenotype and barrier function of kindlin-2-deficient keratinocytes and skin equivalents. These findings have physiological and pathological significance, since kindlin-2 expression modulates the phenotype in Kindler syndrome, a skin fragility disorder caused by kindlin-1 deficiency. Our results suggest that pharmacological regulation of RhoGTPase activity may represent a therapeutic option for skin fragility.
authors.affiliation: Department of Dermatology, Medical Centre-University of Freiburg, Germany.
authors.forename: Yinghong
authors.initials: Y
authors.lastname: He
authors.forename: Tanja
authors.initials: T
authors.lastname: Sonnenwald
authors.forename: Adrian
authors.initials: A
authors.lastname: Sprenger
authors.forename: Uwe
authors.initials: U
authors.lastname: Hansen
authors.forename: Joern
authors.initials: J
authors.lastname: Dengjel
authors.forename: Leena
authors.initials: L
authors.lastname: Bruckner-Tuderman
authors.forename: Gudula
authors.initials: G
authors.lastname: Schmidt
authors.forename: Cristina
authors.initials: C
authors.lastname: Has
mesh_terms: D001427:Bacterial Toxins / Q000494:pharmacology*; D002448:Cell Adhesion / Q000187:drug effects*; D002450:Cell Communication / Q000187:drug effects*; D002460:Cell Line; D018920:Coculture Techniques; D004789:Enzyme Activation; D004817:Epidermis / Q000187:drug effects* / Q000201:enzymology / Q000473:pathology; D061252:Feeder Cells; D055785:Gene Knockdown Techniques; D005838:Genotype; D006801:Humans; D015603:Keratinocytes / Q000187:drug effects* / Q000201:enzymology / Q000473:pathology; D008565:Membrane Proteins / Q000172:deficiency* / Q000235:genetics; D009363:Neoplasm Proteins / Q000172:deficiency* / Q000235:genetics; D010539:Permeability; D010641:Phenotype; D034622:RNA Interference; D011994:Recombinant Proteins / Q000494:pharmacology; D015398:Signal Transduction / Q000187:drug effects; D014162:Transfection; D020742:rhoA GTP-Binding Protein / Q000378:metabolism*
chemical_list: D001427:Bacterial Toxins; C477322:FERMT3 protein, human; D008565:Membrane Proteins; D009363:Neoplasm Proteins; D011994:Recombinant Proteins; C066737:RHOA protein, human; D020742:rhoA GTP-Binding Protein
keywords: actin; blistering; epidermal adhesion; epidermal barrier; integrin