Semaphorin 3A Promotes Dendrite Elongation of Osteocytes in Association with Down-regulation of CDK6.
BACKGROUND
Osteocytes, which comprise over 90% of all bone cells, communicate with osteoblasts and osteoclasts to regulate each other's physiological function via dendrites, suggesting that dendrite elongation plays a vital role for bone regeneration. We examined the effect of semaphorin 3A (SEMA3A) on dendritic processes of an osteocyte cell line, since in previous work we found it to be essential for promoting osteoblast differentiation.


METHODS
Dendrite length was analyzed by Cellomics Array Scan VTI quantitatively in osteocyte-like cell line, MLO-Y4 cells. We performed cell proliferation assay. Gene and protein expression was examined by real-time reverse-transcriptase polymerase chain reaction and western blotting, respectively.


RESULTS
Both total and average dendrite length were significantly increased in MLO-Y4 cells stimulated with SEMA3A compared to control. E11 protein was up-regulated upon SEMA3A stimulation. Moreover, cyclin-dependent kinase 6 (CDK6) was down-regulated in a time-dependent manner. Taken together, these results suggest that SEMA3A regulates dendrites of osteocytes in association with down-regulation of CDK6. SEMA3A may be a promising drug to apply for bone tissue engineering.
Department of Oral and Maxillofacial Surgery, Saitama Medical University, Saitama, Japan Niimura Dental Clinic, Tokyo, Japan.
Masahiro
M
Niimura
Department of Oral and Maxillofacial Surgery, Saitama Medical University, Saitama, Japan tsato@saitama-med.ac.jp.
Tsuyoshi
T
Sato
Department of Oral and Maxillofacial Surgery, Saitama Medical University, Saitama, Japan.
Yuichiro
Y
Enoki
Department of Oral and Maxillofacial Surgery, Saitama Medical University, Saitama, Japan.
Masahiko
M
Okubo
Division of Molecular Signaling and Biochemistry, Department of Health Promotion, Kyushu Dental University, Fukuoka, Japan.
Shoichiro
S
Kokabu
Department of Physiology and Cell Biology, Tokyo Medical and Dental University, Tokyo, Japan.
Shu
S
Takeda
Department of Oral and Maxillofacial Surgery, Saitama Medical University, Saitama, Japan.
Tetsuya
T
Yoda
D000818:Animals; D015153:Blotting, Western; D002460:Cell Line; D049109:Cell Proliferation / Q000187:drug effects / Q000235:genetics; D051361:Cyclin-Dependent Kinase 6 / Q000378:metabolism*; D003712:Dendrites / Q000187:drug effects* / Q000502:physiology; D015536:Down-Regulation / Q000187:drug effects*; D015870:Gene Expression / Q000187:drug effects; D008562:Membrane Glycoproteins / Q000235:genetics / Q000378:metabolism; D051379:Mice; D010011:Osteocytes / Q000187:drug effects* / Q000378:metabolism / Q000502:physiology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D040121:Semaphorin-3A / Q000494:pharmacology*; D013997:Time Factors; D000098853:Podoplanin
D051361:Cyclin-Dependent Kinase 6; D008562:Membrane Glycoproteins; D040121:Semaphorin-3A; C490441:Pdpn protein, mouse; D000098853:Podoplanin; C495912:Cdk6 protein, mouse
CDK6; Semaphorin 3A; dendrite elongation; osteocyte