PUBLICATION

Cellular dynamics of regeneration reveals role of two distinct Pax7 stem cell populations in larval zebrafish muscle repair

Authors
Pipalia, T.G., Koth, J., Roy, S.D., Hammond, C.L., Kawakami, K., Hughes, S.M.
ID
ZDB-PUB-160507-9
Date
2016
Source
Disease models & mechanisms   9(6): 671-84 (Journal)
Registered Authors
Hammond, Chrissy, Hughes, Simon M., Kawakami, Koichi, Koth, Jana
Keywords
Myotome, Myogenesis, Myogenin, Myoblast heterogeneity, Fusion, Somite, Satellite cell, Injury
MeSH Terms
  • Wound Healing*
  • Muscle Fibers, Skeletal/metabolism
  • Stem Cells/metabolism*
  • Leukocytes/metabolism
  • Transgenes
  • Genes, Reporter
  • PAX2 Transcription Factor/metabolism*
  • Animals
  • Time Factors
  • Cell Differentiation
  • Muscle, Skeletal/pathology*
  • Green Fluorescent Proteins/metabolism
  • Regeneration*
  • Cell Fusion
  • Cell Nucleus/metabolism
  • Zebrafish Proteins/metabolism*
  • Somites/metabolism
  • Time-Lapse Imaging
  • Zebrafish/metabolism*
  • Cell Proliferation
  • Epidermis/metabolism
  • Larva/metabolism
(all 22)
PubMed
27149989 Full text @ Dis. Model. Mech.
Abstract
Heterogeneity of stem cells or their niches is likely to influence tissue regeneration. Here we reveal stem/precursor cell diversity during wound repair in larval zebrafish somitic body muscle using time-lapse 3D confocal microscopy on reporter lines. Skeletal muscle with incision wounds rapidly regenerates both slow and fast muscle fibre types. A swift immune response is followed by an increase in cells at the wound site, many of which express the muscle stem cell marker Pax7. Pax7(+) cells proliferate and then undergo terminal differentiation involving Myogenin accumulation and subsequent loss of Pax7 followed by elongation and fusion to repair fast muscle fibres. Analysis of pax7a and pax7b transgenic reporter fish reveals that cells expressing each of the duplicated pax7 genes are distinctly localized in un-injured larvae. Cells marked by pax7a only or by both pax7a and pax7b enter the wound rapidly and contribute to muscle wound repair, but each behaves differently. Low numbers of pax7a-only cells form nascent fibres. Time-lapse microscopy revealed that the more numerous Pax7b-marked cells frequently fuse to pre-existing fibres, contributing more strongly than pax7a-only cells to repair of damaged fibres. Pax7b-marked cells are more often present in rows of aligned cells that are observed to fuse into a single fibre, but more rarely contribute to nascent regenerated fibres. Ablation of a substantial portion of nitroreductase-expressing pax7b cells with metronidazole prior to wounding triggered rapid pax7a-only cell accumulation, but this neither inhibited nor augmented pax7a-only cell derived myogenesis and thus altered the cellular repair dynamics during wound healing. Moreover, pax7a-only cells did not regenerate pax7b cells, suggesting a lineage distinction. We propose a modified founder cell/fusion competent cell model in which pax7a-only cells initiate fibre formation and pax7b cells contribute to fibre growth. This novel cellular complexity in muscle wound repair raises the possibility that distinct populations of myogenic cells contribute differentially to repair in other vertebrates.
Genes / Markers
Figures
Figure Gallery (15 images) / 2
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Expression
Phenotype
Mutations / Transgenics
Allele Construct Type Affected Genomic Region
a9
    Complex
    c264TgTransgenic Insertion
      i104TgTransgenic Insertion
        i114TgTransgenic Insertion
          i135TgTransgenic Insertion
            kca66TgTransgenic Insertion
              nkgsaizGFFD164AGtTransgenic Insertion
              nkuasgfp1aTgTransgenic Insertion
                nkuasrfp1aTgTransgenic Insertion
                  nz117TgTransgenic Insertion
                    1 - 10 of 14
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                    Human Disease / Model
                    No data available
                    Sequence Targeting Reagents
                    No data available
                    Fish
                    Antibodies
                    Name Type Antigen Genes Isotypes Host Organism
                    Ab1-myogpolyclonalIgGRabbit
                    Ab-A4.1025monoclonal
                      IgG2aMouse
                      Ab-F59monoclonal
                        IgG1Mouse
                        Ab-Pax7monoclonal
                          IgG1Mouse
                          1 - 4 of 4
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                          Orthology
                          No data available
                          Engineered Foreign Genes
                          Marker Marker Type Name
                          EGFPEFGEGFP
                          GAL4FFEFGGAL4FF
                          GFPEFGGFP
                          mCherryEFGmCherry
                          NTREFGNTR
                          RFPEFGRFP
                          1 - 6 of 6
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                          Mapping
                          No data available