Deletion of SA β-Gal+ Cells Using Senolytics Improves Muscle Regeneration in Old Mice

Authors

Cory M. Dungan, University of KentuckyFollow
Kevin A. Murach, University of KentuckyFollow
Christopher J. Zdunek, University of Kentucky
Zuo Jian Tang, Boehringer Ingelheim Pharmaceuticals Inc.
Georgia L. VonLehmden, University of KentuckyFollow
Camille R. Brightwell, University of KentuckyFollow
Zachary Hettinger, University of KentuckyFollow
Davis A. Englund, University of KentuckyFollow
Zheng Liu, Boehringer Ingelheim Pharmaceuticals Inc.
Christopher S. Fry, University of KentuckyFollow
Antonio Filareto, Boehringer Ingelheim Pharmaceuticals Inc.
Michael Franti, Boehringer Ingelheim Pharmaceuticals Inc.
Charlotte A. Peterson, University of KentuckyFollow

Abstract

Systemic deletion of senescent cells leads to robust improvements in cognitive, cardiovascular, and whole-body metabolism, but their role in tissue reparative processes is incompletely understood. We hypothesized that senolytic drugs would enhance regeneration in aged skeletal muscle. Young (3 months) and old (20 months) male C57Bl/6J mice were administered the senolytics dasatinib (5 mg/kg) and quercetin (50 mg/kg) or vehicle bi-weekly for 4 months. Tibialis anterior (TA) was then injected with 1.2% BaCl₂ or PBS 7- or 28 days prior to euthanization. Senescence-associated β-Galactosidase positive (SA β-Gal+) cell abundance was low in muscle from both young and old mice and increased similarly 7 days following injury in both age groups, with no effect of D+Q. Most SA β-Gal+ cells were also CD11b+ in young and old mice 7- and 14 days following injury, suggesting they are infiltrating immune cells. By 14 days, SA β-Gal+/CD11b+ cells from old mice expressed senescence genes, whereas those from young mice expressed higher levels of genes characteristic of anti-inflammatory macrophages. SA β-Gal+ cells remained elevated in old compared to young mice 28 days following injury, which were reduced by D+Q only in the old mice. In D+Q-treated old mice, muscle regenerated following injury to a greater extent compared to vehicle-treated old mice, having larger fiber cross-sectional area after 28 days. Conversely, D+Q blunted regeneration in young mice. In vitro experiments suggested D+Q directly improve myogenic progenitor cell proliferation. Enhanced physical function and improved muscle regeneration demonstrate that senolytics have beneficial effects only in old mice.

Document Type

Article

Publication Date

12-13-2021

Notes/Citation Information

Published in Aging Cell, e13528.

© 2021 The Authors

This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

Digital Object Identifier (DOI)

https://doi.org/10.1111/acel.13528

Funding Information

This research was supported by NIH grants AG049806 and AG069909 to C.A.P and AG063944 to K.A.M. The Glenn Foundation for Medical Research also provided support for this project.

Repository Citation

Dungan, Cory M.; Murach, Kevin A.; Zdunek, Christopher J.; Tang, Zuo Jian; VonLehmden, Georgia L.; Brightwell, Camille R.; Hettinger, Zachary; Englund, Davis A.; Liu, Zheng; Fry, Christopher S.; Filareto, Antonio; Franti, Michael; and Peterson, Charlotte A., "Deletion of SA β-Gal+ Cells Using Senolytics Improves Muscle Regeneration in Old Mice" (2021). Physical Therapy Faculty Publications. 128.
https://uknowledge.uky.edu/rehabsci_facpub/128