Gene expression data at the single cell level of human hamstring, deltoid, supraspinatus muscle; as well as, cultured human muscle fibroadipogenic cells (FAPs)
Ontology highlight
ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE227548 | GEO | 2026/07/13
REPOSITORIES: GEO
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Project description:Utilizing glycerol intramuscular injections in M. musculus provides a model of skeletal muscle damage followed by skeletal muscle regeneration. In particular, glycerol-induced muscle injury triggers accute activation of muscle Fibro/Adipogenic Progenitors, also called FAPs. However, aging dramatically impairs FAP function. We characterized genome-wide expression profiles of young and old FAPs in the non-proliferative and activated state, freshly isolated to non-injured or damaged muscles, respectively. Our goal was to uncover new regulatory signalings specific to FAP entry into the activation program that are affected with age.
2018-11-26 | GSE92508 | GEO
Project description:Muscle fibrosis is a key pathological feature of Duchenne muscular dystrophy (DMD) and is closely associated with disease progression. Fibroadipogenic progenitors (FAPs) are major contributors to fibrosis, yet the precise mechanisms remain unclear. To investigate FAP dynamics and lineage specification, we generated dual-reporter mice (PRURD2) by crossing D2.B10-Dmdmdx/J (D2-mdx) mice with FAP and brown/beige adipose tissue (BAT) reporter lines. Corresponding control mice (PRURDBA) were established on the DBA/2J background. At 12 months, heart, diaphragm, and tibialis anterior (TA) muscles were collected for histological analysis. FAPs were isolated via FACS and subjected to single-cell RNA sequencing. PRURD2 mice exhibited increased fibrosis across all muscles compared to controls (p < 0.01) and a significant rise in PDGFRα-GFP+ FAPs (p < 0.05). UMAP clustering identified 11 distinct FAP subpopulations, with the fibrosis-associated CD55 cluster enriched in PRURD2 mice. Pseudotime analysis showed lineage progression from progenitor clusters toward the fibrogenic CD55 cluster. CellChat analysis indicated increased interactions in PRURD2 mice involving fibrosis-related pathways like COLLAGEN, TGF-β, WNT, NOTCH, and ANGPTL. Additionally, fibrosis-related signaling pathways such as THY1, TWEAK, EPHA, EPHB, and SEMA6 showed increased interactions among FAP clusters in PRURD2 mice. Differential gene expression analysis revealed top upregulated genes including Cxcl13, Cxcl3, Ly6d, Klk1, Fgf23, Serpinb2, Mmp13, Ccl17, Postn, and Adam12. PRURD2 mice develop severe fibrosis in skeletal and cardiac muscle, driven by FAP-induced signaling pathways and genes. This model is valuable for understanding muscle fibrosis in DMD and developing anti-fibrotic therapies.
2026-08-12 | GSE322960 | GEO
Project description:Fibroadipogenic progenitors (FAPs) play a key role in skeletal muscle homeostasis and regeneration. They produce extracellular matrix components and secrete cytokines that regulate muscle stem cell function. The number of FAPs and their activity need to be dynamically regulated to avoid their chronic accumulation and overproduction of fibrosis. However, the intrinsic factors by which FAPs control their cell fate decisions remain elusive. Here, we show that FAPs-secreted prostaglandin-E2 (PGE2) functions as a key autoregulatory factor. Using single cell lipidomics and single cell transcriptomics, we show that FAPs are the main cellular source of PGE2 in resting muscle and during regeneration. FAP-secreted PGE2 exerts paracrine effects that maintain the muscle stem cell pool at steady state and stimulate their proliferation post-injury. Moreover, it has autocrine effects that influence FAP fate decisions and promote their apoptosis. Administration of non-steroidal anti-inflammatory drugs that inhibit the prostaglandin-synthesizing enzyme COX2 increases FAPs content post-injury. Using Pdgfrα-CreERT2_Cox2flox mice, we showed that conditional ablation of COX2 specifically in FAPs increases FAPs content, fibrosis, and impairs muscle regeneration, which can be rescued by PGE2 administration. Furthermore, we show that PGE2 production in FAPs is impaired in mouse models of Duchenne muscular dystrophy, and we provide a proof-of-concept that PGE2 administration can reduce FAPs numbers, fibrosis accumulation, and increase muscle strength. Overall, we uncover a novel role for PGE2 beyond its function in inflammation and identify a mechanism by which FAPs intrinsically regulate their own cell fate, revealing therapeutic potential for muscle injury and dystrophic conditions.
2026-06-05 | GSE320353 | GEO
Project description:Muscle fibroadipogenic progenitor (FAP) cells, which are muscular mesenchymal cells that originate from lateral plate mesoderm have been proposed to act as a critical regulator for adult muscle homeostasis1–7, including the maturation and proper functioning of the neuromuscular junction (NMJ)3, Prx-Bap1 paper. However, the mechanism and intercellular crosstalk by which FAPs regulate the stability and functionality of neuromuscular system remains unknown. Here we show that FAPs not only locally but also systemically regulate the neuromuscular system through the secretion of a serine-type endopeptidase Granzyme E which may imply the previously unidentified endocrine function of FAPs. Local transplantation of wild-type FAPs into the neuromuscular disease model (Prrx1Cre;Bap1f/f, hereafter, cKO) can readily prevent neuromuscular defects, including degeneration of the neuromuscular junction and loss of motor neurons. These effects are found not only in transplanted hindlimb muscles but also in the contralateral hindlimb and even forelimb muscles. Notably, subcutaneous administration of microparticles encapsulating FAP-conditioned media into cKO mice was sufficient to restore normal neuromuscular functions. By analyzing the transcriptomic and secretomic profiles of FAPs, we identified a novel protein, Granzyme E, which is specifically expressed in and secreted by FAPs, and which indispensably regulates the structure and function of NMJ and motor neuron survival. Our study has defined a unique mechanism of Granzyme E-dependent, systemic control of the neuromuscular system by FAPs, which would provide a comprehensive understanding on the neuromuscular systems and their crosstalk with non-neuronal cells. These findings may provide a therapeutic benefit to treat NMJ-related diseases.
2022-08-31 | GSE199660 | GEO
Project description:Gene expression data at the single cell level of human hamstring, deltoid, supraspinatus muscle as well as, cultured human muscle fibroadipogenic cells (FAPs)
| PRJNA945484 | ENA
Project description:The purpose of this study is to investigate how melatonin-influenced promyogenic factor secreted from fibro-adipogenic progenitors (FAPs) regulate muscle regeneration and muscle cell fusion during muscle repair. We highlighted the role of melatonin in regulating crosstalk between muscle stem cells and FAPs during muscle regeneration. Mice that were treated with melatonin exhibited improved muscle regeneration and reduced intramuscular fat deposition, which were associated with enhanced myogenesis, remodeled lipid metabolism and reduced immune cell infiltration. Notably, melatonin did not exert positive effects on cell fusion and myotube formation during differentiation. Interestingly, melatonin repressed fibro-adipogenic progenitor (FAP) adipogenesis in a dose-dependent manner in vitro. Furthermore, melatonin treatment enhanced the pro-myogenic effects of FAPs, which stimulated GDF10 secretion to promote muscle cell fusion and induce myotube hypertrophy.
2023-06-30 | GSE214008 | GEO
Project description:Wagyu cattle are renowned for their premium beef characterized by abundant intramuscular fat (IMF). In contrast, Brahman, a popular breed in the southern coastal area of the US, generally produces tough meat with scarce IMF. However, the mechanisms underlying the differential meat quality between the two breeds are still largely unknown. Using single-cell RNAseq (scRNAseq), we identified many tissue-resident and immune cell types in Wagyu, Brahman, and Wagyu/Brahman crossbred cattle muscle. Multiple fibro/adipogenic progenitor (FAP) subpopulations were identified, including an endomysial adipogenic subpopulation and a perimysial fibrogenic subpopulation. Further analysis comparing individual FAP subpopulations between Wagyu and Brahman identified stronger pro-adipogenic gene expression in Wagyu adipogenic FAP subpopulation and higher pro-fibrogenic gene expression in Brahman fibrogenic FAP subpopulation. Overexpression of CFD, a gene upregulated in Wagyu adipogenic FAPs, enhanced the adipogenic efficiency of FAPs. Moreover, the expression of CFD in FAPs was positively correlated with the IMF content. Interestingly, the expression of CFD was identified in human FAPs but not FAPs of mouse models of intramuscular adipogenesis, suggesting that CFD is a species-specific regulator of IMF formation. Using a mouse line that allows lineage-tracing of FAPs expressing Postn, a gene upregulated in Brahman FAPs, we found that Postn expression was specifically activated during fibrogenic but not adipogenic programming. Cell-cell communication analysis revealed robust interactions between FAPs and other cell types, further suggesting the critical role of FAPs in bovine skeletal muscle growth, development, and homeostasis.
2023-07-01 | GSE205347 | GEO
Project description:Fibro-Adipogenic Progenitors (FAPs) are mesenchymal progenitor cells vital for muscle homeostasis and regeneration, but they also produce fibrosis and differentiate into intramuscular fat under pathological conditions. Insulin-like Growth Factor-I (IGF-I), a key regulator of muscle repair, influences satellite cell activity, macrophage polarization, and extracellular matrix (ECM) remodeling. Although FAPs are a major source of IGF-I in muscle, its specific role remains unclear. Thus, we generated inducible FAP-specific Igf1 knockout mice (FID mice) to determine the necessity of the FAP IGF-I source. After acute BaCl2 injury, FID mice exhibited impaired muscle regeneration, characterized by fewer Pax7+ cells, increased CD68+ macrophage accumulation, smaller fibers with lower proportions of EmbMHC+ fibers, and reduced ECM content compared to controls. FAP proliferation was impaired, with fewer total and Ki67+ FAPs in regenerating muscles from FID mice. Following glycerol injury, muscles from FID mice exhibited reduced adipocyte accumulation. To probe the autocrine role of FAP IGF-I, we isolated FAPs from muscles 3 days post-injury. Primary FAPs isolated from FID mice had blunted growth, accompanied by upregulation of immune-regulatory genes and downregulation of ECM and cell proliferation genes by RNASeq. Additionally, cultured FID FAPs had delayed differentiation and sustained PDGFRα expression in response to TGF-β, as well as impaired adipocyte differentiation in adipogenic media. Finally, FID FAPs entered a senescent state shortly after Cre recombination, showing high β-Gal expression in vivo and in vitro, and suppression of IGF-IR and IGF-I-dependent pathways. Taken together, our findings demonstrate that IGF-I derived from FAPs is a critical autocrine factor, with its absence leading to impaired function of FAPs for maintenance of muscle regenerative capacity
2025-11-19 | GSE282309 | GEO
Project description:Fatty infiltration, the ectopic deposition of adipose tissue within skeletal muscle, is mediated via the adipogenic differentiation of fibro-adipogenic progenitors (FAPs). We used single-nuclei and single-cell RNA sequencing to characterize FAP heterogeneity in patients with fatty infiltration. We identified an MME+ FAP subpopulation which, based on ex vivo characterization as well as transplantation experiments, exhibits high adipogenic potential. MME+ FAPs are characterized by low activity of WNT, known to control adipogenic commitment, and are refractory to the inhibitory role of WNT activators. Using preclinical models for muscle damage versus fatty infiltration, we show that many MME+ FAPs undergo apoptosis during muscle regeneration and differentiate into adipocytes under pathological conditions, leading to their depletion. Finally, we utilized the varying fat infiltration levels in human hip muscles to show the depletion of MME+ FAPs in fatty infiltrated human muscle. Altogether, we have identified the dominant adipogenic FAP subpopulation in skeletal muscle.
2023-01-18 | GSE200487 | GEO
Project description:Fibro-adipogenic progenitors (FAPs) are muscle-resident mesenchymal progenitors that can contribute to muscle tissue homeostasis and regeneration, as well as postnatal maturation and lifelong maintenance of the neuromuscular system. Recently, traumatic injury to the peripheral nerve was shown to activate FAPs, suggesting that FAPs can respond to nerve injury. However, questions of how FAPs can sense the anatomically distant peripheral nerve injury and whether FAPs can directly contribute to nerve regeneration remained unanswered. Here, utilizing single-cell transcriptomics and mouse models, we discovered that a subset of FAPs expressing GDNF receptors Ret and Gfra1 can respond to peripheral nerve injury by sensing GDNF secreted by Schwann cells. Upon GDNF sensing, this subset becomes activated and expresses Bdnf. FAP-specific inactivation of Bdnf (Prrx1-Cre; Bdnf-fl/fl) resulted in delayed nerve regeneration owing to defective remyelination, indicating that GDNF-sensing FAPs play an important role in the remyelination process during peripheral nerve regeneration. In aged mice, significantly reduced Bdnf expression in FAPs was observed upon nerve injury, suggesting the clinical relevance of FAP-derived BDNF in the age-related delays in nerve regeneration. Collectively, our study revealed the previously unidentified role of FAPs in peripheral nerve regeneration, and the molecular mechanism behind FAPs’ response to peripheral nerve injury.
2024-07-30 | GSE250436 | GEO