Fibro-adipogenic progenitors of dystrophic mice are insensitive to NOTCH regulation of adipogenesis

Fibro-adipogenic progenitors (FAPs) promote satellite cell differentiation in adult skeletal muscle regeneration. However, in pathological conditions, FAPs are responsible for fibrosis and fatty infiltrations. Here we show that the NOTCH pathway negatively modulates FAP differentiation both in vitro and in vivo. However, FAPs isolated from young dystrophin-deficient mdx mice are insensitive to this control mechanism. An unbiased mass spectrometry–based proteomic analysis of FAPs from muscles of wild-type and mdx mice suggested that the synergistic cooperation between NOTCH and inflammatory signals controls FAP differentiation. Remarkably, we demonstrated that factors released by hematopoietic cells restore the sensitivity to NOTCH adipogenic inhibition in mdx FAPs. These results offer a basis for rationalizing pathological ectopic fat infiltrations in skeletal muscle and may suggest new therapeutic strategies to mitigate the detrimental effects of fat depositions in muscles of dystrophic patients.

Download Full-text

Skeletal muscle fibro-adipogenic progenitors of dystrophic mice are insensitive to NOTCH-dependent regulation of adipogenesis

10.1101/223370 ◽

2017 ◽

Cited By ~ 1

Author(s):

Milica Marinkovic ◽

Francesca Sacco ◽

Filomena Spada ◽

Lucia Lisa Petrilli ◽

Claudia Fuoco ◽

...

Keyword(s):

Skeletal Muscle ◽

Cell Mass ◽

Notch Pathway ◽

Notch Signaling Pathway ◽

Skeletal Muscle Regeneration ◽

Mdx Mice ◽

List Type ◽

Adult Skeletal Muscle

SummaryFibro adipogenic progenitors (FAPs) promote satellite cell differentiation in adult skeletal muscle regeneration. However, in pathological conditions, FAPs are responsible for fibrosis and fat infiltrations. Here we show that the NOTCH pathway negatively modulates FAP differentiation both in vitro and in vivo. However, FAPs isolated from young dystrophin-deficient mdx mice are insensitive to this control mechanism. Nonetheless, factors released by hematopoietic cells restore the sensitivity to NOTCH adipogenic inhibition. An unbiased mass spectrometry-based proteomic analysis of FAPs from muscles of wild type and mdx mice, revealed that the synergistic cooperation between NOTCH and inflammatory signals controls FAP differentiation. These results offer a basis for rationalizing the pathological outcomes of fat infiltrations in skeletal muscle and may suggest new therapeutic strategies to mitigate the detrimental effects of fatty depositions in muscles of dystrophic patients.HighlightsSingle-cell mass cytometry reveals that wt and mdx FAPs are in different cell states.Activation of the NOTCH signaling pathway negatively regulates adipogenesis of wt but not mdx FAPs.Deep proteomics suggests a mechanism explaining the different sensitivity of mdx- FAPs to NOTCH.TNF-a stimulation restores the anti-adipogenic effect of NOTCH in mdx FAPs.

Download Full-text

Plasmin activity is required for myogenesis in vitro and skeletal muscle regeneration in vivo

Blood ◽

10.1182/blood.v99.8.2835 ◽

2002 ◽

Vol 99 (8) ◽

pp. 2835-2844 ◽

Cited By ~ 62

Author(s):

Mònica Suelves ◽

Roser López-Alemany ◽

Frederic Lluı́s ◽

Gloria Aniorte ◽

Erika Serrano ◽

...

Keyword(s):

Skeletal Muscle ◽

Muscle Regeneration ◽

Myoblast Fusion ◽

Skeletal Muscle Regeneration ◽

Wild Type ◽

Plasmin Activity ◽

Type Plasminogen Activator ◽

Deficient Mice

Abstract Plasmin, the primary fibrinolytic enzyme, has a broad substrate spectrum and is implicated in biologic processes dependent upon proteolytic activity, such as tissue remodeling and cell migration. Active plasmin is generated from proteolytic cleavage of the zymogen plasminogen (Plg) by urokinase-type plasminogen activator (uPA) and tissue-type plasminogen activator (tPA). Here, we have investigated the role of plasmin in C2C12 myoblast fusion and differentiation in vitro, as well as in skeletal muscle regeneration in vivo, in wild-type and Plg-deficient mice. Wild-type mice completely repaired experimentally damaged skeletal muscle. In contrast, Plg−/− mice presented a severe regeneration defect with decreased recruitment of blood-derived monocytes and lymphocytes to the site of injury and persistent myotube degeneration. In addition, Plg-deficient mice accumulated fibrin in the degenerating muscle fibers; however, fibrinogen depletion of Plg-deficient mice resulted in a correction of the muscular regeneration defect. Because we found that uPA, but not tPA, was induced in skeletal muscle regeneration, and persistent fibrin deposition was also reproducible in uPA-deficient mice following injury, we propose that fibrinolysis by uPA-dependent plasmin activity plays a fundamental role in skeletal muscle regeneration. In summary, we identify plasmin as a critical component of the mammalian skeletal muscle regeneration process, possibly by preventing intramuscular fibrin accumulation and by contributing to the adequate inflammatory response after injury. Finally, we found that inhibition of plasmin activity with α2-antiplasmin resulted in decreased myoblast fusion and differentiation in vitro. Altogether, these studies demonstrate the requirement of plasmin during myogenesis in vitro and muscle regeneration in vivo.

Download Full-text

Lactate Metabolism and Satellite Cell Fate

Frontiers in Physiology ◽

10.3389/fphys.2020.610983 ◽

2020 ◽

Vol 11 ◽

Author(s):

Minas Nalbandian ◽

Zsolt Radak ◽

Masaki Takeda

Keyword(s):

Skeletal Muscle ◽

Cell Fate ◽

Cell Communication ◽

Cell Types ◽

Short Review ◽

Skeletal Muscle Regeneration ◽

Metabolic Switch ◽

Adult Skeletal Muscle

Lactate is one of the metabolic products of glycolysis. It is widely accepted as an important energy source for many cell types and more recently has been proposed to actively participate in cell-cell communication. Satellite cells (SCs), which are adult skeletal muscle stem cells, are the main players of the skeletal muscle regeneration process. Recent studies have proposed a metabolic switch to increase glycolysis in activated SCs. Moreover, lactate has been shown to affect SCs and myoblasts in vivo and in vitro. In this short review, we describe how metabolic variations relate with SC fate (quiescence, activation, proliferation, migration, differentiation, fusion, and self-renewal), as well as discuss possible relationships between lactate as a metabolite and as a signaling molecule affecting SC fate.

Download Full-text

A Nonerythroid Isoform of Protein 4.1R Interacts with Components of the Contractile Apparatus in Skeletal Myofibers

Molecular Biology of the Cell ◽

10.1091/mbc.11.11.3805 ◽

2000 ◽

Vol 11 (11) ◽

pp. 3805-3817 ◽

Cited By ~ 29

Author(s):

Aikaterini Kontrogianni-Konstantopoulos ◽

Shu-Ching Huang ◽

Edward J. Benz

Keyword(s):

Skeletal Muscle ◽

Protein S ◽

Binding Assays ◽

Adult Skeletal Muscle ◽

Exon 2 ◽

Alternatively Spliced ◽

Translation Initiation Codon ◽

Protein 4.1R

The ∼80-kDa erythroid 4.1R protein is a major component of the erythrocyte cytoskeleton, where it links transmembrane proteins to the underlying spectrin/actin complexes. A diverse collection of 4.1R isoforms has been described in nonerythroid cells, ranging from ∼30 to ∼210 kDa. In the current study, we identified the number and primary structure of 4.1R isoforms expressed in adult skeletal muscle and characterized the localization patterns of 4.1R message and protein. Skeletal muscle 4.1R appears to originate solely from the upstream translation initiation codon (AUG-1) residing in exon 2′. Combinations of alternatively spliced downstream exons generate an array of distinct 4.1R spliceoforms. Two major isoform classes of ∼105/110 and ∼135 kDa are present in muscle homogenates. 4.1R transcripts are distributed in highly ordered signal stripes, whereas 4.1R protein(s) decorate the sarcoplasm in transverse striations that are in register with A-bands. An ∼105/110-kDa 4.1R isoform appears to occur in vivo in a supramolecular complex with major sarcomeric proteins, including myosin, α-actin, and α-tropomyosin. In vitro binding assays showed that 4.1R may interact directly with the aforementioned contractile proteins through its 10-kDa domain. All of these observations suggest a topological model whereby 4.1R may play a scaffolding role by anchoring the actomyosin myofilaments and possibly modulating their displacements during contraction/relaxation.

Download Full-text

Urokinase-dependent plasminogen activation is required for efficient skeletal muscle regeneration in vivo

Blood ◽

10.1182/blood.v97.6.1703 ◽

2001 ◽

Vol 97 (6) ◽

pp. 1703-1711 ◽

Cited By ~ 82

Author(s):

Frederic Lluı́s ◽

Josep Roma ◽

Mònica Suelves ◽

Maribel Parra ◽

Gloria Aniorte ◽

...

Keyword(s):

Skeletal Muscle ◽

Plasminogen Activator ◽

Muscle Regeneration ◽

Plasminogen Activators ◽

Skeletal Muscle Regeneration ◽

Plasminogen Activation ◽

Wild Type ◽

Type Plasminogen Activator ◽

Deficient Mice

Plasminogen activators urokinase-type plasminogen activator (uPA) and tissue-type plasminogen activator (tPA) are extracellular proteases involved in various tissue remodeling processes. A requirement for uPA activity in skeletal myogenesis was recently demonstrated in vitro. The role of plasminogen activators in skeletal muscle regeneration in vivo in wild-type, uPA-deficient, and tPA-deficient mice is investigated here. Wild-type and tPA−/− mice completely repaired experimentally damaged skeletal muscle. In contrast, uPA−/− mice had a severe regeneration defect, with decreased recruitment of blood-derived monocytes to the site of injury and with persistent myotube degeneration. In addition, uPA-deficient mice accumulated fibrin in the degenerating muscle fibers; however, the defibrinogenation of uPA-deficient mice resulted in a correction of the muscle regeneration defect. A similar severe regeneration deficit with persistent fibrin deposition was also reproducible in plasminogen-deficient mice after injury, suggesting that fibrinolysis by uPA-mediated plasminogen activation plays a fundamental role in skeletal muscle regeneration. In conclusion, the uPA-plasmin system is identified as a critical component of the mammalian skeletal muscle regeneration process, possibly because it prevents intramuscular fibrin accumulation and contributes to the adequate inflammatory response after injury. These studies demonstrate the requirement of an extracellular proteolytic cascade during muscle regeneration in vivo.

Download Full-text

Molecular Targets of Androgen Signaling that Characterize Skeletal Muscle Recovery and Regeneration

Nuclear Receptor Signaling ◽

10.1621/nrs.13005 ◽

2015 ◽

Vol 13 (1) ◽

pp. nrs.13005 ◽

Cited By ~ 11

Author(s):

James G. MacKrell ◽

Benjamin C. Yaden ◽

Heather Bullock ◽

Keyue Chen ◽

Pamela Shetler ◽

...

Keyword(s):

Skeletal Muscle ◽

Molecular Targets ◽

Gene Signature ◽

Muscle Recovery ◽

In Vivo Models ◽

Adult Skeletal Muscle ◽

Injury Model ◽

Androgen Regulation

The high regenerative capacity of adult skeletal muscle relies on a self-renewing depot of adult stem cells, termed muscle satellite cells (MSCs). Androgens, known mediators of overall body composition and specifically skeletal muscle mass, have been shown to regulate MSCs. The possible overlapping function of androgen regulation of muscle growth and MSC activation has not been carefully investigated with regards to muscle regeneration. Therefore, the aim of this study was to examine coinciding androgen-mediated genetic changes in an in vitro MSC model and clinically relevant in vivo models. A gene signature was established via microarray analysis for androgen-mediated MSC engagement and highlighted several markers including follistatin (FST), IGF-1, C-X-C chemokine receptor 4 (CXCR4), hepatocyte growth factor (HGF) and glucocorticoid receptor (GR/Nr3c1). In an in vivo muscle atrophy model, androgen re-supplementation significantly increased muscle size and expression of IGF-1, FST, and HGF, while significantly decreasing expression of GR. Biphasic gene expression profiles over the 7-day re-supplementation period identifed temporal androgen regulation of molecular targets involved in satellite cell engagement into myogenesis. In a muscle injury model, removal of androgens resulted in delayed muscle recovery and regeneration. Modifications in the androgen signaling gene signature, along with reduced Pax7 and MyoD expression, suggested that limited MSC activation and increased inflammation contributed to the delayed regeneration. However, enhanced MSC activation in the androgen-deplete mouse injury model was driven by an androgen receptor (AR) agonist. These results provide novel in vitro and in vivo evidence describing molecular targets of androgen signaling, while also increasing support for translational use of AR agonists in skeletal muscle recovery and regeneration.

Download Full-text

FGF-2–dependent signaling activated in aged human skeletal muscle promotes intramuscular adipogenesis

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.2021013118 ◽

2021 ◽

Vol 118 (37) ◽

pp. e2021013118 ◽

Cited By ~ 1

Author(s):

Sebastian Mathes ◽

Alexandra Fahrner ◽

Umesh Ghoshdastider ◽

Hannes A. Rüdiger ◽

Michael Leunig ◽

...

Keyword(s):

Skeletal Muscle ◽

Transcriptional Activation ◽

Human Skeletal Muscle ◽

Muscle Growth ◽

Muscle Cells ◽

Adeno Associated Virus ◽

Adult Skeletal Muscle

Aged skeletal muscle is markedly affected by fatty muscle infiltration, and strategies to reduce the occurrence of intramuscular adipocytes are urgently needed. Here, we show that fibroblast growth factor-2 (FGF-2) not only stimulates muscle growth but also promotes intramuscular adipogenesis. Using multiple screening assays upstream and downstream of microRNA (miR)-29a signaling, we located the secreted protein and adipogenic inhibitor SPARC to an FGF-2 signaling pathway that is conserved between skeletal muscle cells from mice and humans and that is activated in skeletal muscle of aged mice and humans. FGF-2 induces the miR-29a/SPARC axis through transcriptional activation of FRA-1, which binds and activates an evolutionary conserved AP-1 site element proximal in the miR-29a promoter. Genetic deletions in muscle cells and adeno-associated virus–mediated overexpression of FGF-2 or SPARC in mouse skeletal muscle revealed that this axis regulates differentiation of fibro/adipogenic progenitors in vitro and intramuscular adipose tissue (IMAT) formation in vivo. Skeletal muscle from human donors aged >75 y versus <55 y showed activation of FGF-2–dependent signaling and increased IMAT. Thus, our data highlights a disparate role of FGF-2 in adult skeletal muscle and reveals a pathway to combat fat accumulation in aged human skeletal muscle.

Download Full-text

PEDF-derived peptide promotes skeletal muscle regeneration through its mitogenic effect on muscle progenitor cells

AJP Cell Physiology ◽

10.1152/ajpcell.00344.2014 ◽

2015 ◽

Vol 309 (3) ◽

pp. C159-C168 ◽

Cited By ~ 18

Author(s):

Tsung-Chuan Ho ◽

Yi-Pin Chiang ◽

Chih-Kuang Chuang ◽

Show-Li Chen ◽

Jui-Wen Hsieh ◽

...

Keyword(s):

Skeletal Muscle ◽

Cell Proliferation ◽

Cyclin D1 ◽

Satellite Cell ◽

Muscle Regeneration ◽

Muscle Fibers ◽

Skeletal Muscle Regeneration ◽

Satellite Cell Proliferation

In response injury, intrinsic repair mechanisms are activated in skeletal muscle to replace the damaged muscle fibers with new muscle fibers. The regeneration process starts with the proliferation of satellite cells to give rise to myoblasts, which subsequently differentiate terminally into myofibers. Here, we investigated the promotion effect of pigment epithelial-derived factor (PEDF) on muscle regeneration. We report that PEDF and a synthetic PEDF-derived short peptide (PSP; residues Ser93-Leu112) induce satellite cell proliferation in vitro and promote muscle regeneration in vivo. Extensively, soleus muscle necrosis was induced in rats by bupivacaine, and an injectable alginate gel was used to release the PSP in the injured muscle. PSP delivery was found to stimulate satellite cell proliferation in damaged muscle and enhance the growth of regenerating myofibers, with complete regeneration of normal muscle mass by 2 wk. In cell culture, PEDF/PSP stimulated C2C12 myoblast proliferation, together with a rise in cyclin D1 expression. PEDF induced the phosphorylation of ERK1/2, Akt, and STAT3 in C2C12 myoblasts. Blocking the activity of ERK, Akt, or STAT3 with pharmacological inhibitors attenuated the effects of PEDF/PSP on the induction of C2C12 cell proliferation and cyclin D1 expression. Moreover, 5-bromo-2′-deoxyuridine pulse-labeling demonstrated that PEDF/PSP stimulated primary rat satellite cell proliferation in myofibers in vitro. In summary, we report for the first time that PSP is capable of promoting the regeneration of skeletal muscle. The signaling mechanism involves the ERK, AKT, and STAT3 pathways. These results show the potential utility of this PEDF peptide for muscle regeneration.

Download Full-text

Conditional Deletion of Dicer in Adult Mice Impairs Skeletal Muscle Regeneration

International Journal of Molecular Sciences ◽

10.3390/ijms20225686 ◽

2019 ◽

Vol 20 (22) ◽

pp. 5686 ◽

Cited By ~ 2

Author(s):

Satoshi Oikawa ◽

Minjung Lee ◽

Takayuki Akimoto

Keyword(s):

Skeletal Muscle ◽

Muscle Regeneration ◽

Myogenic Differentiation ◽

Tibialis Anterior Muscle ◽

Critical Factor ◽

Skeletal Muscle Regeneration ◽

Small Noncoding Rnas ◽

Adult Mice

Skeletal muscle has a remarkable regenerative capacity, which is orchestrated by multiple processes, including the proliferation, fusion, and differentiation of the resident stem cells in muscle. MicroRNAs (miRNAs) are small noncoding RNAs that mediate the translational repression or degradation of mRNA to regulate diverse biological functions. Previous studies have suggested that several miRNAs play important roles in myoblast proliferation and differentiation in vitro. However, their potential roles in skeletal muscle regeneration in vivo have not been fully established. In this study, we generated a mouse in which the Dicer gene, which encodes an enzyme essential in miRNA processing, was knocked out in a tamoxifen-inducible way (iDicer KO mouse) and determined its regenerative potential after cardiotoxin-induced acute muscle injury. Dicer mRNA expression was significantly reduced in the tibialis anterior muscle of the iDicer KO mice, whereas the expression of muscle-enriched miRNAs was only slightly reduced in the Dicer-deficient muscles. After cardiotoxin injection, the iDicer KO mice showed impaired muscle regeneration. We also demonstrated that the number of PAX7+ cells, cell proliferation, and the myogenic differentiation capacity of the primary myoblasts did not differ between the wild-type and the iDicer KO mice. Taken together, these data demonstrate that Dicer is a critical factor for muscle regeneration in vivo.

Download Full-text