Single Stem Cell Imaging and Analysis Reveals Telomere Length Differences inDiseased Human and Mouse Skeletal Muscles.

Elisia D Tichy,Scott Mubarak,Alessandra Sacco,David K Sidibe,Harish Hosalkar,F Brad Johnson,Maryam Sharifi-Sanjani,Michael J Stec,Foteini Mourkioti,Matthew T Tierney

doi:10.1016/j.stemcr.2017.08.003

Abstract

SummaryMuscle stem cells (MuSCs) contribute to muscle regeneration following injury. In many muscle disorders, the repeated cycles of damage and repair lead to stem cell dysfunction. While telomere attrition may contribute to aberrant stem cell functions, methods to accurately measure telomere length in stem cells from skeletal muscles have not been demonstrated. Here, we have optimized and validated such a method, named MuQ-FISH, for analyzing telomere length in MuSCs from either mice or humans. Our analysis showed no differences in telomere length between young and aged MuSCs from uninjured wild-type mice, but MuSCs isolated from young dystrophic mice exhibited significantly shortened telomeres. In corroboration, we demonstrated that telomere attrition is present in human dystrophic MuSCs, which underscores its importance in diseased regenerative failure. The robust technique described herein provides analysis at a single-cell resolution and may be utilized for other cell types, especially rare populations of cells.

Highlights

Telomeres are long, repetitive DNA sequences (50-TTAGGG-30) that are present at chromosome ends (Collins, 2000)
After validating the MuQ-fluorescence in situ hybridization (FISH) method using mice lacking the RNA component of telomerase (TERC/TR), we showed that there were no telomere length differences in Muscle stem cells (MuSCs) isolated from uninjured young and old mice
Validation of MuQ-FISH The effect of telomere length on maintaining tissue homeostasis and stem cell function has been studied in many tissues

Summary

Introduction

Repetitive DNA sequences (50-TTAGGG-30) that are present at chromosome ends (Collins, 2000). During each cycle of DNA replication, telomeres shorten, as DNA polymerases have no primers available to complex with and extend DNA (Ohki et al, 2001). Telomere shortening can result from aberrant nuclease activity (Wu et al, 2012). Eroded telomeres activate the DNA damage response, inducing cellular senescence and/or the activation of cell death processes (Shay and Wright, 2005). Cells have evolved mechanisms to combat such a dilemma. The action of telomerase (TERT), an RNA primer (TERC/TR), and accessory factors can extend telomere length in cells where these components are expressed and active (Sarek et al, 2015). The proper functioning of this pathway could play a crucial role in the regulation of stem cell aging and the prevention of the stem cell dysfunctional phenotype observed in degenerative disorders (Blasco, 2007b; Flores and Blasco, 2010)

Results

Discussion

Conclusion