Expression of beta-1 integrin in human developing salivary glands and its parallel relation with maturation markers: in situ hybridisation and immunofluorescence study

BACKGROUND AND OBJECTIVE: Salivary gland development entails co-ordinated processes involving complex molecular interactions in which integrins have a fundamental role. The integrins are a family of heterodimeric transmembrane receptors comprising alpha and beta subunits that mediate intercellular and extracellular signals involved in the organisation of cells in tissues and organs during development. The beta-1 integrin in particular have been implicated in proliferation and differentiation of cells involved in the development of epithelial tissues. To understand the role of beta-1 integrin in salivary gland development we have studied its expression in human foetal tissues. DESIGN: In situ hybridisation was used to compare the expression and localisation of integrin beta-1 with differentiation markers in developing human salivary glands obtained from foetuses of 8-24 weeks gestation. RESULTS: Integrin beta-1 first appeared during bud stage in a few cells and its distribution increased as salivary gland morphogenesis progressed. This increased pattern of beta-1 integrin expression was coincident with the appearance of the differentiation markers CK14, CK low MW and smooth-muscle actin. CONCLUSIONS: The developmentally regulated expression of integrin beta-1 in association with the establishment of a mature phenotype indicated by salivary gland tissue differentiation markers is suggestive of its role in salivary gland morphogenesis.