Grant: Catalyst Grant: Bone Health

Apolipoprotein D (apoD) is a glycoprotein that is associated, in mammals, to High Density Lipoproteins (HDL), a key player in lipid metabolism, but it is widespread to other species such as chicken, plants and insects. Structurally, it belongs to the large lipocalin family of proteins that transport small hydrophobic ligands. In the case of apoD, it includes cholesterol, progesterone, pregnenolone, bilirubine, arachidonic acid and possibly other molecules. In human, the gene is expressed in all tissues at varying concentrations: low in the liver and intestine but high in spleen, adrenals, brain, lung, testis, and kidney. The gene expression is induced by growth arrest, oxidative stress and inflammatory molecules. No study has yet discovered the precise role of apoD but it is very likely a multi-ligand-multi-function protein. Our preliminary results indicate that mice lacking apoD present a lower trabecular bone mass of the femur when compared to the Wild Type mice resembling very much osteoporosis in human. Thus, these mice represent a good model to study this disease.