Cellular and Molecular Regulation of Muscle Regeneration

2004 ◽  
Vol 84 (1) ◽  
pp. 209-238 ◽  
Author(s):  
SOPHIE B. P. CHARGÉ ◽  
MICHAEL A. RUDNICKI

Chargé, Sophie B. P., and Michael A. Rudnicki. Cellular and Molecular Regulation of Muscle Regeneration. Physiol Rev 84: 209–238, 2004; 10.1152/physrev.00019.2003.—Under normal circumstances, mammalian adult skeletal muscle is a stable tissue with very little turnover of nuclei. However, upon injury, skeletal muscle has the remarkable ability to initiate a rapid and extensive repair process preventing the loss of muscle mass. Skeletal muscle repair is a highly synchronized process involving the activation of various cellular responses. The initial phase of muscle repair is characterized by necrosis of the damaged tissue and activation of an inflammatory response. This phase is rapidly followed by activation of myogenic cells to proliferate, differentiate, and fuse leading to new myofiber formation and reconstitution of a functional contractile apparatus. Activation of adult muscle satellite cells is a key element in this process. Muscle satellite cell activation resembles embryonic myogenesis in several ways including the de novo induction of the myogenic regulatory factors. Signaling factors released during the regenerating process have been identified, but their functions remain to be fully defined. In addition, recent evidence supports the possible contribution of adult stem cells in the muscle regeneration process. In particular, bone marrow-derived and muscle-derived stem cells contribute to new myofiber formation and to the satellite cell pool after injury.

2018 ◽  
Vol 315 (5) ◽  
pp. C714-C721 ◽  
Author(s):  
Irena A. Rebalka ◽  
Cynthia M. F. Monaco ◽  
Nina E. Varah ◽  
Thorsten Berger ◽  
Donna M. D’souza ◽  
...  

Lipocalin-2 (LCN2) is an adipokine previously described for its contribution to numerous processes, including innate immunity and energy metabolism. LCN2 has also been demonstrated to be an extracellular matrix (ECM) regulator through its association with the ECM protease matrix metalloproteinase-9 (MMP-9). With the global rise in obesity and the associated comorbidities related to increasing adiposity, it is imperative to gain an understanding of the cross talk between adipose tissue and other metabolic tissues, such as skeletal muscle. Given the function of LCN2 on the ECM in other tissues and the importance of matrix remodeling in skeletal muscle regeneration, we examined the localization and expression of LCN2 in uninjured and regenerating wild-type skeletal muscle and assessed the impact of LCN2 deletion (LCN2−/−) on skeletal muscle repair following cardiotoxin injury. Though LCN2 was minimally present in uninjured skeletal muscle, its expression was increased significantly at 1 and 2 days postinjury, with expression present in Pax7-positive satellite cells. Although satellite cell content was unchanged, the ability of quiescent satellite cells to become activated was significantly impaired in LCN2−/− skeletal muscles. Skeletal muscle regeneration was also significantly compromised as evidenced by decreased embryonic myosin heavy chain expression and smaller regenerating myofiber areas. Consistent with a role for LCN2 in MMP-9 regulation, regenerating muscle also displayed a significant increase in fibrosis and lower ( P = 0.07) MMP-9 activity in LCN2−/− mice at 2 days postinjury. These data highlight a novel role for LCN2 in muscle regeneration and suggest that changes in adipokine expression can significantly impact skeletal muscle repair.


2020 ◽  
Vol 319 (1) ◽  
pp. C116-C128
Author(s):  
Nasibeh Daneshvar ◽  
Ryuichi Tatsumi ◽  
Jason Peeler ◽  
Judy E. Anderson

Satellite cell (SC) activation, mediated by nitric oxide (NO), is essential to myogenic repair, whereas myotube function requires innervation. Semaphorin (Sema) 3A, a neuro-chemorepellent, is thought to regulate axon guidance to neuromuscular junctions (NMJs) during myotube differentiation. We tested whether “premature” SC activation (SC activation before injury) by a NO donor (isosorbide dinitrate) would disrupt early myogenesis and/or NMJs. Adult muscle was examined during regeneration in two models of injury: myotoxic cardiotoxin (CTX) and traumatic crush (CR) ( n = 4–5/group). Premature SC activation was confirmed by increased DNA synthesis by SCs immediately in pretreated mice after CTX injury. Myotubes grew faster after CTX than after CR; growth was accelerated by pretreatment. NMJ maturation, classified by silver histochemistry (neurites) and acetylcholinesterase (AchE), and α-bungarotoxin staining (Ach receptors, AchRs) were delayed by pretreatment, consistent with a day 6 rise in the denervation marker γ-AchR. With pretreatment, S100B from terminal Schwann cells (TSCs) increased 10- to 20-fold at days 0 and 10 after CTX and doubled 6 days after CR. Premature SC activation disrupted motoneuritogenesis 8–10 days post-CTX, as pretreatment reduced colocalization of pre- and postsynaptic NMJ features and increased Sema3A-65. Premature SC activation before injury both accelerated myogenic repair and disrupted NMJ remodeling and maturation, possibly by reducing Sema3A neuro-repulsion and altering S100B. This interpretation extends the model of Sema3A-mediated motoneuritogenesis during muscle regeneration. Manipulating the timing and type of Sema3A by brief NO effects on SCs suggests an important role for TSCs and Sema3A-65 processing in axon guidance and NMJ restoration during muscle repair.


2011 ◽  
Vol 366 (1575) ◽  
pp. 2297-2306 ◽  
Author(s):  
Jennifer L. Shadrach ◽  
Amy J. Wagers

Skeletal muscle is a highly specialized tissue composed of non-dividing, multi-nucleated muscle fibres that contract to generate force in a controlled and directed manner. Skeletal muscle is formed during embryogenesis from a subset of muscle precursor cells, which generate both differentiated muscle fibres and specialized muscle-forming stem cells known as satellite cells. Satellite cells remain associated with muscle fibres after birth and are responsible for muscle growth and repair throughout life. Failure in satellite cell function can lead to delayed, impaired or failed recovery after muscle injury, and such failures become increasingly prominent in cases of progressive muscle disease and in old age. Recent progress in the isolation of muscle satellite cells and elucidation of the cellular and molecular mediators controlling their activity indicate that these cells represent promising therapeutic targets. Such satellite cell-based therapies may involve either direct cell replacement or development of drugs that enhance endogenous muscle repair mechanisms. Here, we discuss recent breakthroughs in understanding both the cell intrinsic and extrinsic regulators that determine the formation and function of muscle satellite cells, as well as promising paths forward to realizing their full therapeutic potential.


2019 ◽  
Author(s):  
Brandon J. Gheller ◽  
Jamie E. Blum ◽  
Erica L. Bender ◽  
Mary E. Gheller ◽  
Esther W. Lim ◽  
...  

SummarySkeletal muscle regeneration is reliant on a population of muscle specific adult stem cells (muscle progenitor cells; MPCs). During regeneration, the MPC population undergoes a transient and rapid period of population expansion, which is necessary to repair damaged myofibers and restore muscle homeostasis. Much research has focused on the age-related accumulation of negative regulators of regeneration, while the age-related decline of nutrient and metabolic determinants of the regenerative process needs examination. We hypothesized that older individuals, a population that is at risk for protein malnutrition, have diminished availability of amino acids that are necessary for MPC function. Here, we identified that levels of the non-essential amino acid serine are reduced in the skeletal muscle of healthy, older individuals. Furthermore, using stable-isotope tracing studies, we demonstrate that primary, human MPCs (hMPCs) exhibit a limited capacity for de novo biosynthesis of serine and the closely related amino acid glycine. We identified that serine and glycine are essential for hMPC proliferation and, therefore, population expansion. Serine and glycine were necessary to support synthesis of the intracellular antioxidant glutathione, and restriction of serine and glycine was sensed in an EIF2α-dependent manner resulting in cell cycle arrest in G0/G1. In conclusion, we elucidate that, despite an absolute requirement of serine/glycine for hMPC proliferation, availability of serine in the skeletal muscle microenvironment is limited to the hMPCs of healthy older adults and is a likely underlying mechanism for impaired skeletal muscle regeneration with advancing age. Graphical Abstract


2018 ◽  
Author(s):  
Palanikumar Manoharan ◽  
Taejeong Song ◽  
Tatiana L Radzyukevich ◽  
Sakthivel Sadayappan ◽  
Jerry B Lingrel ◽  
...  

Regeneration of adult skeletal muscle after injury is coordinated by complex interactions between the injured muscle and the innate immune system. Myeloid lineage cells predominate in this process. This study examined the role of Krüppel like factor 2 (KLF2), a zinc-finger transcription factor that regulates myeloid cell activation state, in muscle regeneration. Gastrocnemius muscles of wild-type and myeKlf2-/- mice, which lack KLF2 in all myeloid cells, were subjected to cardiotoxin injury and followed for 21 days. Injured muscles of myeKlf2-/- contained more infiltrating, inflammatory Ly6C+ monocytes, with elevated expression of inflammatory mediators. Infiltrating monocytes matured earlier into pro-inflammatory macrophages with phenotype Ly6C+, CD11b+, F4/80+. Inflammation resolved earlier and progressed to myogenesis, marked by an earlier decline of Ly6C+ macrophages and their replacement with anti-inflammatory Ly6C- populations, in association with elevated expression of factors that resolve inflammation and promote myogenesis. Overall, regeneration was completed earlier. These findings identify myeloid KLF2 as a central regulator of the innate immune response to acute skeletal muscle injury. Manipulating myeloid KLF2 levels may be a useful strategy for accelerating regeneration.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Sean M. Buchanan ◽  
Feodor D. Price ◽  
Alessandra Castiglioni ◽  
Amanda Wagner Gee ◽  
Joel Schneider ◽  
...  

Abstract Satellite cells are the canonical muscle stem cells that regenerate damaged skeletal muscle. Loss of function of these cells has been linked to reduced muscle repair capacity and compromised muscle health in acute muscle injury and congenital neuromuscular diseases. To identify new pathways that can prevent loss of skeletal muscle function or enhance regenerative potential, we established an imaging-based screen capable of identifying small molecules that promote the expansion of freshly isolated satellite cells. We found several classes of receptor tyrosine kinase (RTK) inhibitors that increased freshly isolated satellite cell numbers in vitro. Further exploration of one of these compounds, the RTK inhibitor CEP-701 (also known as lestaurtinib), revealed potent activity on mouse satellite cells both in vitro and in vivo. This expansion potential was not seen upon exposure of proliferating committed myoblasts or non-myogenic fibroblasts to CEP-701. When delivered subcutaneously to acutely injured animals, CEP-701 increased both the total number of satellite cells and the rate of muscle repair, as revealed by an increased cross-sectional area of regenerating fibers. Moreover, freshly isolated satellite cells expanded ex vivo in the presence of CEP-701 displayed enhanced muscle engraftment potential upon in vivo transplantation. We provide compelling evidence that certain RTKs, and in particular RET, regulate satellite cell expansion during muscle regeneration. This study demonstrates the power of small molecule screens of even rare adult stem cell populations for identifying stem cell-targeting compounds with therapeutic potential.


2004 ◽  
Vol 166 (3) ◽  
pp. 347-357 ◽  
Author(s):  
Peter S. Zammit ◽  
Jon P. Golding ◽  
Yosuke Nagata ◽  
Valérie Hudon ◽  
Terence A. Partridge ◽  
...  

Growth, repair, and regeneration of adult skeletal muscle depends on the persistence of satellite cells: muscle stem cells resident beneath the basal lamina that surrounds each myofiber. However, how the satellite cell compartment is maintained is unclear. Here, we use cultured myofibers to model muscle regeneration and show that satellite cells adopt divergent fates. Quiescent satellite cells are synchronously activated to coexpress the transcription factors Pax7 and MyoD. Most then proliferate, down-regulate Pax7, and differentiate. In contrast, other proliferating cells maintain Pax7 but lose MyoD and withdraw from immediate differentiation. These cells are typically located in clusters, together with Pax7−ve progeny destined for differentiation. Some of the Pax7+ve/MyoD−ve cells then leave the cell cycle, thus regaining the quiescent satellite cell phenotype. Significantly, noncycling cells contained within a cluster can be stimulated to proliferate again. These observations suggest that satellite cells either differentiate or switch from terminal myogenesis to maintain the satellite cell pool.


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