TYPE-VIII COLLAGEN IS A PRODUCT OF VASCULAR SMOOTH-MUSCLE CELLS IN DEVELOPMENT AND DISEASE

Type VIII collagen is a short-chain collagen with considerable similar ity to type X collagen. We have generated chain-specific antibodies to the alpha 1 and alpha 2 chains of type VIII collagen, and used them a s probes to examine the synthesis of type VIII collagen by vascular sm ooth muscle cells (VSMC). In addition, chain-specific oligonucleotides have been used in reverse transcriptase-PCR (RT-PCR) reactions with R NA extracted from cultured smooth muscle cells in culture and from fre shly isolated vascular tissues. Radiolabelling of VSMC in culture and immunoprecipitation with chain-specific antibodies showed that both ch ains were expressed. Lower levels of type VIII collagen were found in adult VSMC than in neonatal VSMC. RT-PCR showed that both chains were expressed in tissues as well as cells in culture. The results indicate that type VIII collagen is a product of VSMC of normal adult vessels and is expressed at high levels by VSMC in vascular lesions.