title: ILK modulates epithelial polarity and matrix formation in hair follicles.
abstract: Hair follicle morphogenesis requires coordination of multiple signals and communication between its epithelial and mesenchymal constituents. Cell adhesion protein platforms, which include integrins and integrin-linked kinase (ILK), are critical for hair follicle formation. However, their precise contribution to this process is poorly understood. We show that in the absence of ILK, the hair follicle matrix lineage fails to develop, likely due to abnormalities in development of apical-basal cell polarity, as well as in laminin-511 and basement membrane assembly at the tip of the hair bud. These defects also result in impaired specification of hair matrix and absence of precortex and inner sheath root cell lineages. The molecular pathways affected in ILK-deficient follicles are similar to those in the absence of epidermal integrin β1 and include Wnt, but not sonic hedgehog, signaling. ILK-deficient hair buds also show abnormalities in the dermal papilla. Addition of exogenous laminin-511 restores morphological and molecular markers associated with hair matrix formation, indicating that ILK regulates hair bud cell polarity and functions upstream from laminin-511 assembly to regulate the developmental progression of hair follicles beyond the germ stage.
authors.affiliation: Department of Physiology and Pharmacology, University of Western Ontario, London, ON N6A 5C1, Canada Children's Health Research Institute and Lawson Health Research Institute, University of Western Ontario, London, ON N6A 5C1, Canada.
authors.forename: Alena
authors.initials: A
authors.lastname: Rudkouskaya
authors.forename: Ian
authors.initials: I
authors.lastname: Welch
authors.forename: Lina
authors.initials: L
authors.lastname: Dagnino
mesh_terms: D000818:Animals; D016764:Cell Polarity; D004847:Epithelial Cells / Q000166:cytology / Q000378:metabolism; D005109:Extracellular Matrix / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D018859:Hair Follicle / Q000166:cytology* / Q000254:growth & development / Q000378:metabolism; D015603:Keratinocytes / Q000166:cytology / Q000378:metabolism; D051379:Mice; D017346:Protein Serine-Threonine Kinases / Q000502:physiology*; D015398:Signal Transduction; D000099200:Scaffold Protein ILK
chemical_list: D017346:Protein Serine-Threonine Kinases; D000099200:Scaffold Protein ILK