Evy Lundgren-Åkerlund

We have previously identified and characterised the collagen type II-binding integrin subunit α10, which is a member of the β1 family and is expressed by chondrocytes. In the present study, we examined the expression of the α10 integrin in various mouse tissues. Immunohistochemical analysis of α10 on cryosections from 3-day-old mice demonstrated that α10β1 was present in the hyaline cartilage of joints, vertebral column, trachea and bronchi. In addition, α10 was found in the ossification groove of Ranvier, in the aortic and atrioventricular valves of the heart and in the fibrous tissue lining skeletal muscle and ligaments. Overall, the distribution was distinct from that of the collagen-binding integrins α1β1 and α2β1. We also found that α10β1was the dominating collagen-binding integrin during cartilage development. Expression of α10 appeared at embryonic day 11.5 (E11.5) at the same time as chondrogenesis started as judged by collagen type II expression. At E13.5, α10 was present throughout the anlage as well as in the perichondrium and in mesenchyme just outside the perichondrium, where it localised with collagen type I. Four weeks after birth, α10 was prominent both at the articular surface and in the growth plate. In conclusion, we found that integrin α10β1 was a major collagen-binding integrin during cartilage development and in mature hyaline cartilage. In addition, we found that α10β1 was present in some fibrous tissues.