title: Myogenic skeletal muscle satellite cells communicate by tunnelling nanotubes.
abstract: Quiescent satellite cells sit on the surface of the muscle fibres under the basal lamina and are activated by a variety of stimuli to disengage, divide and differentiate into myoblasts that can regenerate or repair muscle fibres. Satellite cells adopt their parent's fibre type and must have some means of communication with the parent fibre. The mechanisms behind this communication are not known. We show here that satellite cells form dynamic connections with muscle fibres and other satellite cells by F-actin based tunnelling nanotubes (TNTs). Our results show that TNTs readily develop between satellite cells and muscle fibres. Once developed, TNTs permit transport of intracellular material, and even cellular organelles such as mitochondria between the muscle fibre and satellite cells. The onset of satellite cell differentiation markers Pax-7 and MyoD expression was slower in satellite cells cultured in the absence than in the presence of muscle cells. Furthermore physical contact between myofibre and satellite cell progeny is required to maintain subtype identity. Our data establish that TNTs constitute an integral part of myogenic cell communication and that physical cellular interaction control myogenic cell fate determination.
authors.affiliation: Department of Biotechnology and Molecular Medicine, A. I. Virtanen Institute for Molecular Medicine, University of Kuopio, FIN-70211 Kuopio, Finland. pasi.tavi@uku.fi
authors.forename: Pasi
authors.initials: P
authors.lastname: Tavi
authors.forename: Topi
authors.initials: T
authors.lastname: Korhonen
authors.forename: Sandra L
authors.initials: SL
authors.lastname: Hänninen
authors.forename: Joseph D
authors.initials: JD
authors.lastname: Bruton
authors.forename: Sara
authors.initials: S
authors.lastname: Lööf
authors.forename: Andras
authors.initials: A
authors.lastname: Simon
authors.forename: Håkan
authors.initials: H
authors.lastname: Westerblad
mesh_terms: D008841:Actin Cytoskeleton / Q000378:metabolism / Q000648:ultrastructure; D000818:Animals; D001693:Biological Transport, Active / Q000502:physiology; D002450:Cell Communication / Q000502:physiology*; D002454:Cell Differentiation / Q000502:physiology; D019070:Cell Lineage / Q000502:physiology; D022081:Cell Surface Extensions / Q000378:metabolism / Q000648:ultrastructure; D002478:Cells, Cultured; D017077:Culture Media, Conditioned / Q000494:pharmacology; D008297:Male; D051379:Mice; D024510:Muscle Development / Q000502:physiology*; D018485:Muscle Fibers, Skeletal / Q000378:metabolism / Q000648:ultrastructure; D018482:Muscle, Skeletal / Q000166:cytology / Q000254:growth & development* / Q000378:metabolism*; D017570:MyoD Protein / Q000378:metabolism; D045333:Nanotubes, Peptide; D051763:PAX7 Transcription Factor / Q000378:metabolism; D010641:Phenotype; D032496:Satellite Cells, Skeletal Muscle / Q000502:physiology* / Q000648:ultrastructure
chemical_list: D017077:Culture Media, Conditioned; D017570:MyoD Protein; C057363:MyoD1 myogenic differentiation protein; D045333:Nanotubes, Peptide; D051763:PAX7 Transcription Factor; C497322:Pax7 protein, mouse