Yasuhiko Bando1, Hide Sakashita2, Arata Nagasaka3, Koji Sakiyama4, Nobuko Tokuda5, Shoichi Iseki6, Yuji Owada7, Osamu Amano8. 1. Division of Anatomy, Meikai University School of Dentistry, 1-1 Keyakidai, Sakado, Saitama 3500283, Japan. Electronic address: y-bando@dent.meikai.ac.jp. 2. Division of Anatomy, Meikai University School of Dentistry, 1-1 Keyakidai, Sakado, Saitama 3500283, Japan. Electronic address: ri.sakasita@dent.meikai.ac.jp. 3. Division of Anatomy, Meikai University School of Dentistry, 1-1 Keyakidai, Sakado, Saitama 3500283, Japan. Electronic address: anagasaka@dent.meikai.ac.jp. 4. Division of Anatomy, Meikai University School of Dentistry, 1-1 Keyakidai, Sakado, Saitama 3500283, Japan. Electronic address: sakiyama@dent.meikai.ac.jp. 5. Department of Anatomy (Macro), School of Medicine, Dokkyo Medical University, 880 Kitakobayashi, Mibu, Tochigi 3210293, Japan. Electronic address: tokudan@dokkyomed.ac.jp. 6. Department of Clinical Engineering, Faculty of Health Sciences, Komatsu University, He 14-1 Mukai-motoori-machi, Komatsu, Ishikawa 923-0961, Japan. Electronic address: shoichi.iseki@komatsu-u.ac.jp. 7. Department of Organ Anatomy, Tohoku University Graduate School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai, Miyagi 9808575, Japan. Electronic address: owada@med.tohoku.ac.jp. 8. Division of Anatomy, Meikai University School of Dentistry, 1-1 Keyakidai, Sakado, Saitama 3500283, Japan. Electronic address: oamano@dent.meikai.ac.jp.
Abstract
BACKGROUND: Long-chain fatty acids (LCFAs) and retinoic acid (RA) are abundant in the growth plates (GPs) of long bones; however, their roles have not been elucidated. We observed that epidermal fatty acid-binding protein (E-FABP/FABP5) with a high affinity for both LCFAs and RA is exclusively expressed in the septoclasts located at the chondro-osseous junction (COJ) of the GP. HIGHLIGHTS: E-FABP expressed in septoclasts is involved in both LCFA metabolism and RA signaling as an intracellular transporter of both LCFAs and RA. Septoclasts with shortened cytoplasmic processes are associated with cartilage resorptive activity downregulation because of E-FABP deficiency or excess or deficiency of RA. In ontogeny, the septoclasts are differentiated from the pericytes and involved in the resorption of the uncalcified matrix of the cartilage templates in endochondral ossification. CONCLUSION: Septoclasts originate from pericytes and express E-FABP to play crucial roles in uncalcified matrix resorption by LCFA metabolism and RA signaling during endochondral ossification.
BACKGROUND: Long-chain fatty acids (LCFAs) and retinoic acid (RA) are abundant in the growth plates (GPs) of long bones; however, their roles have not been elucidated. We observed that epidermal fatty acid-binding protein (E-FABP/FABP5) with a high affinity for both LCFAs and RA is exclusively expressed in the septoclasts located at the chondro-osseous junction (COJ) of the GP. HIGHLIGHTS: E-FABP expressed in septoclasts is involved in both LCFA metabolism and RA signaling as an intracellular transporter of both LCFAs and RA. Septoclasts with shortened cytoplasmic processes are associated with cartilage resorptive activity downregulation because of E-FABP deficiency or excess or deficiency of RA. In ontogeny, the septoclasts are differentiated from the pericytes and involved in the resorption of the uncalcified matrix of the cartilage templates in endochondral ossification. CONCLUSION: Septoclasts originate from pericytes and express E-FABP to play crucial roles in uncalcified matrix resorption by LCFA metabolism and RA signaling during endochondral ossification.