Laminin, a Major Basement Membrane Component of the Blood Vessel, as a Negative Regulator of Osteoclastogenesis

Abstract.

Laminin, the major basement membrane glycoprotein of the blood vessel, inducing many cellular responses, inhibited the differentiation of osteoclasts in a rat bone marrow culture system when immobilized on the surface of the culture wells, showing that laminin acts as a negative regulator of osteoclast differentiation in a nonsolubilized form. Laminin inhibited the process of preosteoclast formation from early progenitor cells in bone marrow. This laminin-mediated inhibition of osteoclastogenesis was blocked by the addition of laminin fragment YIGSR, indicating that the inhibitory effect of laminin was mediated via laminin receptors. This finding suggests a significant role of basement membrane laminin of the blood vessels as a negative regulator of osteoclastogenesis.