Met and Cxcr4 cooperate to protect skeletal muscle stem cells against inflammation-induced damage during regeneration
Ines Lahmann,
Joscha Griger,
Jie-Shin Chen,
Yao Zhang,
Markus Schuelke,
Carmen Birchmeier
Affiliations
Ines Lahmann
Neurowissenschaftliches Forschungzentrum, NeuroCure Cluster of Excellence, Charité–Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany; Developmental Biology/Signal Transduction Group, Max Delbrueck Center for Molecular Medicine (MDC) in the Helmholtz Society, Berlin, Germany
Joscha Griger
Developmental Biology/Signal Transduction Group, Max Delbrueck Center for Molecular Medicine (MDC) in the Helmholtz Society, Berlin, Germany
Jie-Shin Chen
Developmental Biology/Signal Transduction Group, Max Delbrueck Center for Molecular Medicine (MDC) in the Helmholtz Society, Berlin, Germany
Yao Zhang
Developmental Biology/Signal Transduction Group, Max Delbrueck Center for Molecular Medicine (MDC) in the Helmholtz Society, Berlin, Germany
Markus Schuelke
Department of Neuropediatrics, Charité–Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
Neurowissenschaftliches Forschungzentrum, NeuroCure Cluster of Excellence, Charité–Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany; Developmental Biology/Signal Transduction Group, Max Delbrueck Center for Molecular Medicine (MDC) in the Helmholtz Society, Berlin, Germany
Acute skeletal muscle injury is followed by an inflammatory response, removal of damaged tissue, and the generation of new muscle fibers by resident muscle stem cells, a process well characterized in murine injury models. Inflammatory cells are needed to remove the debris at the site of injury and provide signals that are beneficial for repair. However, they also release chemokines, reactive oxygen species, as well as enzymes for clearance of damaged cells and fibers, which muscle stem cells have to withstand in order to regenerate the muscle. We show here that MET and CXCR4 cooperate to protect muscle stem cells against the adverse environment encountered during muscle repair. This powerful cyto-protective role was revealed by the genetic ablation of Met and Cxcr4 in muscle stem cells of mice, which resulted in severe apoptosis during early stages of regeneration. TNFα neutralizing antibodies rescued the apoptosis, indicating that TNFα provides crucial cell-death signals during muscle repair that are counteracted by MET and CXCR4. We conclude that muscle stem cells require MET and CXCR4 to protect them against the harsh inflammatory environment encountered in an acute muscle injury.