The ins and outs of muscle stem cell aging

Skeletal Muscle

Table 1 Reports of age-related changes in muscle stem cell function based on purified satellite cell and single muscle fiber transplantation assays

Age of donor	SC or single fiber transplant	Cell number and purification	Genotype and age of recipient	IR host	Muscle injury	Method of detection	Analysis timepoint	Change in SC function (aged relative to adult)	Ref.
4 vs 24 m	SC	2000 Lin-VCAM+, INT-A7	4 m C57Bl6	No	BaCl₂	H2B-GFP marked nuclei per muscle	30 dPI	SC and myofiber: 40 % decline	[13]
5, 22, 30 m	SC	10,000 FACS: Lin-CD31+/INT-A7	4 m NOD/SCID	No	CTX	Lentiviral GFP	21 dPI	Myofiber: 70 % decline	[14]
2 vs 24 m	SC	10–100 (limiting dilution series) FACS	2 m NOD/SCID	Yes	CTX	GFP/Luc or Myf5lacZ	30 d/60 dPI	100 SCs: not different. 10 SCs: 30 % decline in SC	[16]
3 vs 18 m	SC	10,000 Pax7-Zs-green	2–4 m mdx	No	Natural turnover + CTX	Pax-Zs-green and dystrophin antibody	21 dPI	SC: 70 % decline; myofiber: 50 % decline	[17]
4 vs 26 m	Single fiber	5–7 muscle fibers	4 m C57Bl6	No	BaCl₂	SC: β-actin GFP/Pax7+	30 d PI	60 % decline SC repopulation	[15]
1–2 vs 22–30 m	Single fiber	1 muscle fiber	1 m mdx. NOD/SCID	Yes	Natural turnove + repeated CTX	Myonuclei :3F-nlacZ-2E. SC: Myf5lacZ	30 d/40 dPI	SC and myofiber: not different	[41]

The results highlight the different approaches that have been employed to study the effect of age on satellite cell engraftment, self-renewal, and differentiation using purified satellite cell and single muscle fiber transplantation assays
Abbreviations: m month, Lin ⁻ Sca1⁻/CD31⁻/Cd45⁻, NOD/SCID non-obese diabetic/severe combined immune deficiency, Mdx mouse model carrying naturally occurring mutation of dystrophin gene, IR irradiation, CTX cardiotoxin, BaCl ₂ barium chloride, dPI days post injury, GFP/LucZ ubiquitous readout, Myf5lacZ lacZ reporter of myf5 locus, Ref. reference

ISSN: 2044-5040