Proteolysis in Facial Nerve Regeneration

2010 Fiscal Year Final Research Report

• Project/Area Number: 19791314
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Single-year Grants
• Research Field: Plastic surgery
• Research Institution: Kyoto Prefectural University of Medicine
• Principal Investigator: NUMAJIRI Toshiaki Kyoto Prefectural University of Medicine, 医学研究科, 講師 (20326234)
• Project Period (FY): 2007 – 2010
• Keywords: 顔面神経麻痺 / Motopsin / Facial nerve injury / axotomy / GAP-43

Research Abstract

Motopsin is a trypsin-like serine protease which is strongly expressed in nucleus of motoneuron such as facial nucleus. Motopsin has a unique multi-domain serine protease, which has protease domain, kringle domain, and three scavenger receptor cysteine rich domain. We report the expression of motopsin mRNA level in facial nucleus after axotomy and during facial nerve regeneration. After transection axotomy of facial nerve, the transected nerves were caused with microsurgical immediate anastomosis to regenerate innervation. Motopsin and GAP-43 (growth associated protein-43) mRNA expression in facial nucleus were analysed by in situ hybridization, and it revealed that expression of motopsin mRNA was down-regulated at 14th day after axotomy, and that expression recovered with functional recovery of facial nerve. On the contrary, GAP-43 mRNA expression, as a regenerative marker, showed temporal induction until 3 weeks after axotomy, and then reduced with functional recovery. This suggests motopsin may have fundamental role in its motor function, and be possibly indispensable protease.