Integrins are a large family of transmembrane heterodimeric proteins that
constitute the main receptors for extracellular matrix components. Integrins were initially
thought to be primarily involved in the maintenance of cell adhesion and tissue integrity.
However, it is now appreciated that integrins play important roles in many other biological
processes such as cell survival, proliferation, differentiation, migration, cell shape and
polarity. Lung cells express numerous combinations and permutations of integrin
heterodimers. The complexity and diversity of different integrin heterodimers being implicated
in different lung diseases present a major challenge for drug development. Here we provide a comprehensive
overview of the current knowledge of integrins from studies in cell culture to integrin knockout mouse models
and provide an update of results from clinical trials for which integrins are therapeutic targets with a focus on
respiratory diseases (asthma, emphysema, pneumonia, lung cancer, pulmonary fibrosis and sarcoidosis).