Dermal myogenic precursors derive from muscle satellite stem cells

The contribution of non-resident, non-satellite myogenic progenitors to postnatal muscle homeostasis and repair is controversial. Precursor cells with the capacity to generate striated muscle fibers in vitro have been isolated from diverse adult tissues, although their physiological role being currently unclear. Since murine dermis-derived precursor cell cultures generate striated muscle when transplanted in vivo, we pursued to identify and characterize the myogenic cell population present in dermis-derived sphere cultures. Lineage tracing experiments for myogenic, perivascular and dermal precursor cell lineages showed a major contribution of Myf5 and Pax7-positive cell progeny to the dermal myogenic precursor cell subset. Tracing, in situ localization and ultrastructural analyses unequivocally demonstrated that Panniculus carnosus muscle-derived satellite stem cells expand in the dermal sphere culture conditions and originate dermis-derived myofibers in vitro. These results highlight the importance of unraveling distinct lineages in sphere cultures to avoid wrong assumptions when determining the developmental potential of adult stem cells. strain: Crl:CD1(ICR), B6.129S4-Myf5tm3(cre)Sor /J, B6,FVB-Tg(Cspg4-cre)1Akik/J, B195AP-Cre 7 samples were analyzed Myf5SOR+ Sdc4+, Lineage tracing of mouse Myf5SOR+ [B6.129S4-Myf5tm3(cre)Sor /J] Sdc4+, 1 replicate Cspg4- Sdc4+, Lineage tracing of mouse Cspg4- [Fullname strain: B6,FVB-Tg(Cspg4-cre)1Akik/J] Sdc4+, 1 replicate CD1 Sdc4+, Lineage tracing of mouse CD1 [Fullname strain: Crl:CD1(ICR)] Sdc4+, 1 replicate B195AP+ Sdc4-, Lineage tracing of mouse B195AP+ [Fullname strain: B195AP-Cre] Sdc4-, 1 replicate Cspg4- Sdc4-, Lineage tracing of mouse Cspg4- [Fullname strain: B6,FVB-Tg(Cspg4-cre)1Akik/J] Sdc4-, 1 replicate Cspg4+, Lineage tracing of mouse Cspg4+ [Fullname strain: B6,FVB-Tg(Cspg4-cre)1Akik/J], 1 replicate CD1 Sdc4-, Lineage tracing of mouse CD1 [Fullname strain: Crl:CD1(ICR)] Sdc4-, 1 replicate Total RNA was extracted from cells by miRNeasy Micro Kit (50) (217084, Qiagen) and a range between 10 ng and 200 ng of total DNA-free RNA was used as input for labelled cRNA synthesis with the Low Input Quick Amp Labeling Kit (5190-2305, Agilent Technologies), according to manufacturer´s instructions. These cRNA was used on a transcriptome analysis by Agilent SurePrint G3 Mouse GE 8x60K Microarray Kit. Microarray analysis was performed with 8-10 animals per phenotype.