Distinct Phases of Postnatal Skeletal Muscle Growth Govern the Progressive Establishment of Muscle Stem Cell Quiescence

Abstract

Summary Muscle stem cells (or muscle satellite cells [MuSCs]) are required for postnatal growth. Yet, the detailed characterization of myogenic progression and establishment of quiescence during this process remains poorly documented. Here, we provide an overview of myogenic cells heterogeneity and dynamic from birth to adulthood using flow cytometry. We demonstrated that PAX7+ cells acquire an increasing ability to progress in the myogenic program from birth to adulthood. We then simultaneously analyzed the cycling state (KI67 expression) of the MuSCs and progenitors (PAX7+) and their progression into myogenic precursors (PAX7−MYOD+) and differentiating cells (MYOG+) in vivo . We identified two distinct peaks of myogenic differentiation between P7–P10 and P21–P28, and showed that the quiescent MuSC pool is established between 7 and 8 weeks of age. Overall our study provides a comprehensive in vivo characterization of myogenic heterogeneity and demonstrates the highly dynamic nature of skeletal muscle postnatal growth process.

Small-RNA sequencing reveals altered skeletal muscle microRNAs and snoRNAs signatures in weanling male offspring from mouse dams fed a low protein diet during lactation

“…It is also known that miR-1 and −206 suppress Pax7 expression and act as regulators of satellite cell proliferation and differentiation (80). Postnatal muscle hypertrophy may also be regulated by satellite cell number per fibre at birth and their rate of proliferation as well as protein deposition (i.e., protein synthesis and degradation) (82). Therefore, our future studies will focus on satellite cells which will be assessed in histological sections.…”

Chemoradiation impairs myofiber hypertrophic growth in a pediatric tumor model

“…Myonuclear accretion during juvenile muscle development continues up to at least 6 weeks of age (puberty onset) in the mouse, and early adolescence in humans 30,44,[53][54][55] . The adult quiescent SC pool is not fully established until young adult age, and contribution of active SCs is necessary for prepubertal myofiber growth 30,56 . Prepubertal SC ablation leaves both the adult EDL and SOL muscles with reduced myofiber size and myonuclear number 30 .…”

Progressive and Coordinated Mobilization of the Skeletal Muscle Niche throughout Tissue Repair Revealed by Single-Cell Proteomic Analysis

“…Cells were washed with HBSS, and then fixed and permeabilized in 500 µL of Fixation solution (Transcription buffer set, BD Biosciences) for 45 min at +4 °C, in accordance with manufacturer’s instructions. Fixed cells were washed with the Permeabilization/Wash buffer (Transcription buffer set, BD Pharmingen) and proceeded for nuclear immunostaining as previously reported [ 23 ]. The following mix of conjugated antibodies was used: mouse anti-PAX3/7-AF647 (B-5) (Santa Cruz, Dallas, TX, USA #sc-365843), mouse anti-MYOD-PE (BD Biosciences, #554130, custom made coupling by manufacturer), mouse anti-MYOG-AF488 (5FD) (Santa Cruz, #sc-52903), mouse anti-KI67-bV421 (BD Biosciences, #562899).…”

“…The following mix of conjugated antibodies was used: mouse anti-PAX3/7-AF647 (B-5) (Santa Cruz, Dallas, TX, USA #sc-365843), mouse anti-MYOD-PE (BD Biosciences, #554130, custom made coupling by manufacturer), mouse anti-MYOG-AF488 (5FD) (Santa Cruz, #sc-52903), mouse anti-KI67-bV421 (BD Biosciences, #562899). Specificity of the staining was verified using isotypic controls for each antibody [ 23 ]. Cells were washed with the Permeabilization/Wash solution, re-suspended in HBSS and transferred in BD Trucount TM Absolute Counting Tubes (BD Biosciences, #340334) before being analyzed using a BD FACS Canto TM Flow Cytometer (BD Biosciences).…”