Soluble factors mediate the interaction between Schwann cells and osteocytes

Abstract Objective Regenerating loss of bone and nerve tissue is a serious concern among oral and maxillofacial surgeons, yet there is little information regarding the connection between bone metabolism and the nervous system. This study aimed to obtain evidence of this connection. Methods Osteocyte and Schwann cell lines were maintained in a non-contact co-culture system. Quantitative reverse-transcription polymerase chain reactions, immunoblot analyses, and cell proliferation assays were performed. The dendrite length of osteocytes was analyzed quantitatively. Results The dendrite length of osteocytes co-cultured with Schwann cells was significantly increased and associated with E11 protein expression. Schwann cell culture supernatant inhibited osteocyte proliferation and promoted dendrite elongation. However, myelin basic protein in Schwann cells was upregulated in the presence of osteocyte culture supernatant without changes in proliferation and dendrite extension. Schwann cells express the Sema3A gene and co-culture with osteocytes enhanced Sema3A mRNA expression. Conclusions Our data suggest that Schwann cells promote osteocyte maturation via humoral factors including Sema3A and osteocytes regulate myelination of Schwann cells.