Bacterial collagenase type 1

Recombinant mouse LIF, mouse OSM, bone morphogenetic protein-2 (BMP-2), macrophage colony-stimulating factor (M-CSF), RANKL (amino acids 158–316; cat. no. 462-TEC) and the ELISA kits for mouse RANKL and mouse OPG were purchased from R&D Systems, Abingdon, UK; bacterial collagenase type I from Worthington Biochemical Corp., Lakewood, NJ, USA; α-MEM, FBS, L-glutamine, and oligonucleotide primers from Invitrogen, Stockholm, Sweden; RNAqueous®-4PCR RNA isolation kit from Ambion, Inc., Austin TX, USA; 1st strand cDNA synthesis Kit and PCR Core Kit from Roche, Mannheim, Germany; DYEnamic ET terminator cycle sequencing kit from GE Healthcare, Uppsala, Sweden; QIAquick PCR Purification kit was from Qiagen Ltd., Crawley, West Sussex, England; TaqMan Universal PCR Master Mix and TaqMan probes from Applied Biosystems, Foster City, CA, USA; all primary and secondary antibodies used are specified in Supporting Information Table I; anti-IgG-HRP secondary antibodies used for Western blot were from Santa Cruz Biotechnology, Inc., Santa Cruz, CA, USA; culture dishes and multi-well plates from Costar, Cambridge, MA, USA, or Nunc International Corp., Naperville, IL, USA. Indomethacin was kindly supplied by Merck, Sharp & Dohme, Haarlem, the Netherlands; the mouse bone marrow stromal cell line ST-2 from Riken BRC Cell Bank (www.brc.riken.go.jp).