title: Muscle injury-induced thymosin β4 acts as a chemoattractant for myoblasts.
abstract: Thymosin β4 (Tβ4) is a major intracellular G-actin-sequestering peptide. There is increasing evidence to support important extracellular functions of Tβ4 related to angiogenesis, wound healing and cardiovascular regeneration. We investigated the expression of 'Tβ4' and 'thymosin β10', a closely related peptide, during skeletal muscle regeneration in mice and chemotactic responses of myoblasts to these peptides. The mRNA levels of 'Tβ4' and 'thymosin β10' were up-regulated in the early stage of regenerating muscle fibres and inflammatory haematopoietic cells in the injured skeletal muscles of mice. We found that both Tβ4 and its sulphoxized form significantly accelerated wound closure and increased the chemotaxis of C2C12 myoblastic cells. Furthermore, we showed that primary myoblasts and myocytes derived from muscle satellite cells of adult mice were chemoattracted to sulphoxized form of Tβ4. These data indicate that muscle injury enhances the local production of Tβ4, thereby promoting the migration of myoblasts to facilitate skeletal muscle regeneration.
authors.affiliation: Stem Cell Project Group, The Tokyo Metropolitan Institute of Medical Science, Tokyo Metropolitan Organization for Medical Research, 2-1-6 Kamikitazawa, Setagaya-ku, Tokyo 156-8506, Japan.
authors.forename: Yuka
authors.initials: Y
authors.lastname: Tokura
authors.forename: Yuki
authors.initials: Y
authors.lastname: Nakayama
authors.forename: So-Ichiro
authors.initials: S
authors.lastname: Fukada
authors.forename: Noriko
authors.initials: N
authors.lastname: Nara
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Yamamoto
authors.forename: Ryoichi
authors.initials: R
authors.lastname: Matsuda
authors.forename: Takahiko
authors.initials: T
authors.lastname: Hara
mesh_terms: D000818:Animals; D002454:Cell Differentiation / Q000235:genetics; D002460:Cell Line; D002633:Chemotaxis; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018482:Muscle, Skeletal / Q000293:injuries* / Q000473:pathology* / Q000503:physiopathology; D032446:Myoblasts / Q000187:drug effects* / Q000502:physiology; D012333:RNA, Messenger / Q000096:biosynthesis; D012038:Regeneration; D013947:Thymosin / Q000096:biosynthesis* / Q000235:genetics / Q000494:pharmacology; D014158:Transcription, Genetic; D015854:Up-Regulation; D000099201:Thymosin beta(4)
chemical_list: D012333:RNA, Messenger; D013947:Thymosin; D000099201:Thymosin beta(4); C094615:thymosin beta(4) sulfoxide; C039302:thymosin beta(10)