TNFSF11 and osteoporosis: Besides the enhanced expression of genes coding for osteoclast stimulating ligands, e.g. VEGF, TGFB and CSF1 [4], [46], [47], we also detected the osteoporosis-induced expression of Parathyroid hormone receptor PTH1R. Activation of PTH1R triggers osteoblast maturation and induces RANKL expression which leads to osteoclast precursor differentiation and activation [26].