Data supporting possible implication of APOBEC2 in self-renewal functions of myogenic stem satellite cells: Toward understanding the negative regulation of myoblast differentiation

This paper provides in vitro phenotypical data to show that APOBEC2, a member of apoB mRNA editing enzyme, catalytic polypeptide-like family, may implicate in self-renewal functions of myogenic stem satellite cells, namely in the re-establishment of quiescent status after activation and proliferation of myoblasts in single-myofiber culture.


Specifications
Molecular mechanism for myogenic cell fate determination, especially for "self-renewal" functions of satellite cells, is a big research subject and hence of value to the scientific community.
APOBEC2 expression is predominant in skeletal and cardiac muscles and elevated exclusively at the early-differentiation phase of myoblasts in muscle regeneration; however the biological and physiological significance is still unknown.
The particular idea of an essential role for APOBEC2 in the self-renewal functions may extend our understanding of the previous finding that APOBEC2 negatively drives regulation of myoblast differentiation and fusion (see Ref. [1]).

Data
We tested a hypothesis that APOBEC2 may be an important mediator in the "self-renewal" functions of satellite cells, namely in the re-establishment of quiescent status after activation and proliferation. in vitro experiments in mouse single-myofiber cultures prepared from APOBEC2-KO (A2KO) mice demonstrated a significant decrease in the population of Pax7( þ) MyoD(À ) quiescent satellite cells along with a complementary increase in Pax7(À ) MyoD(þ) early-differentiated myoblasts concerned in Ref. [1] (p o0.0005) (Fig. 1), supporting a possible insight that APOBEC2 regulates a competitive balance between two trajectories of proliferated myoblasts during muscle regeneration: a return to cell quiescence which re-establishes the satellite cell pool and their differentiation and fusion which results in myotube formation.

Animal care and use
A2KO mice (C57BL/6 as the background strain) were generated by Dr. Neuberger (Medical Research Council Laboratory of Molecular Biology, United Kingdom) [2] and bred in our laboratory. Inbred C57BL/6 mice were used as WT controls. All animal experiments were conducted in strict accordance with the Guidelines for Proper Conduct of Animal Experiments published by the Science Council of Japan and ethics approvals from the Kyushu University Institutional Review Board (Approval nos. 20-12, 23-62, A22-218, A24-075, A26-078, and A28-090).

Single-fiber isolation and culture
Single myofibers were isolated from extensor digitorum longus (EDL) muscle of 8-wk-old adult male WT and A2KO mice according to Anderson et al. [3] and Ravenscroft et al. [4] with some modifications [5,6]. In brief, EDL muscle was dissected and digested with 0.2% (v/v) collagenase type 1 (CSL-1; Worthington Biochemical, Lakewood, NJ, USA) in high-glucose Dulbecco's modified Eagle's medium (DMEM) for 45 min at 37°C. Muscles were triturated with a flame-polished Pasteur pipette to dissociate them into single muscle fibers, which were then maintained for 72 h in DMEM supplemented with 10% (v/v) normal horse serum (16050-122 from Invitrogen, Grand Island, NY, USA) and 0.5% (v/v) chick embryo extract in a humidified 5% CO 2 atmosphere at 37°C in an incubator followed by Pax7/MyoD-immunostaining.

Statistical analysis
Chi-square tests were employed for statistical analysis of experimental results using Microsoft Excel X for Macintosh. Data are represented as mean 7S.E. and the level of significance was set to p o0.05. Results are representative examples of at least three independent experiments. the Developmental Studies Hybridoma Bank, created by the NICHD of the NIH and maintained at The University of Iowa, Department of Biology, Iowa City, IA 52242.

Transparency document. Supplementary material
Transparency data associated with this article can be found in the online version at http://dx.doi. org/10.1016/j.dib.2017.03.051.