Recombinant human colony-stimulating factor 1 (rhCSF1), TNFSF11 (rhTNFSF11) and MCP-1 (rhMCP-1) were purchased from PeproTech, Inc. α-minimal essential medium (α-MEM), penicillin-streptomycin solution, PBS without calcium and magnesium, FBS, DAPI staining solution and Rhodamine-conjugated phalloidin were purchased from Gibco; Thermo Fisher Scientific, Inc. The tartrate-resistant acid phosphatase (TRAP) staining kit, Escherichia coli (E. coli) LPS, and haematoxylin and eosin (H&E) were purchased from Sigma-Aldrich; Merck KGaA. Cell Counting Kit-8 (CCK-8) reagent was obtained from Dojindo Molecular Technologies, Inc. 7ND protein was purified as previously reported (12 (link)).