RESUMO
BACKGROUND: Muscle atrophy is a typical affliction in patients affected by knee Osteoarthritis (KOA). This study aimed to examine the potential pathogenesis and biomarkers that coalesce to induce muscle atrophy, primarily through the utilization of bioinformatics analysis. METHODS: Two distinct public datasets of osteoarthritis and muscle atrophy (GSE82107 and GSE205431) were subjected to differential gene expression analysis and gene set enrichment analysis (GSEA) to probe for common differentially expressed genes (DEGs) and conduct transcription factor (TF) enrichment analysis from such genes. Venn diagrams were used to identify the target TF, followed by the construction of a protein-protein interaction (PPI) network of the common DEGs governed by the target TF. Hub genes were determined through the CytoHubba plug-in whilst their biological functions were assessed using GSEA analysis in the GTEx database. To validate the study, reverse transcriptase real-time quantitative polymerase chain reaction (qRT-PCR), enzyme-linked immunosorbent assay (ELISA), and Flow Cytometry techniques were employed. RESULTS: A total of 138 common DEGs of osteoarthritis and muscle atrophy were identified, with 16 TFs exhibiting notable expression patterns in both datasets. Venn diagram analysis identified early growth response gene-1 (EGR1) as the target TF, enriched in critical pathways such as epithelial mesenchymal transition, tumor necrosis factor-alpha signaling NF-κB, and inflammatory response. PPI analysis revealed five hub genes, including EGR1, FOS, FOSB, KLF2, and JUNB. The reliability of EGR1 was confirmed by validation testing, corroborating bioinformatics analysis trends. CONCLUSIONS: EGR1, FOS, FOSB, KLF2, and JUNB are intricately involved in muscle atrophy development. High EGR1 expression directly regulated these hub genes, significantly influencing postoperative muscle atrophy progression in KOA patients.
Assuntos
Artroplastia do Joelho , Proteína 1 de Resposta de Crescimento Precoce , Atrofia Muscular , Osteoartrite do Joelho , Humanos , Proteína 1 de Resposta de Crescimento Precoce/genética , Proteína 1 de Resposta de Crescimento Precoce/metabolismo , Atrofia Muscular/metabolismo , Atrofia Muscular/etiologia , Atrofia Muscular/genética , Atrofia Muscular/patologia , Artroplastia do Joelho/efeitos adversos , Osteoartrite do Joelho/genética , Osteoartrite do Joelho/metabolismo , Osteoartrite do Joelho/cirurgia , Osteoartrite do Joelho/patologia , Masculino , Complicações Pós-Operatórias/metabolismo , Complicações Pós-Operatórias/genética , Complicações Pós-Operatórias/etiologia , Feminino , Mapas de Interação de Proteínas/genética , Biomarcadores/metabolismo , Expressão Gênica/genética , Biologia Computacional/métodosRESUMO
Sarcopenia is characterized by accelerated muscle mass and function loss, which burdens and challenges public health worldwide. Several studies indicated that selenium deficiency is associated with sarcopenia; however, the specific mechanism remains unclear. Here, we demonstrated that selenoprotein W (SELENOW) containing selenium in the form of selenocysteine functioned in sarcopenia. SELENOW expression is up-regulated in dexamethasone (DEX)-induced muscle atrophy and age-related sarcopenia mouse models. Knockout (KO) of SELENOW profoundly aggravated the process of muscle mass loss in the two mouse models. Mechanistically, SELENOW KO suppressed the RAC1-mTOR cascade by the interaction between SELENOW and RAC1 and induced the imbalance of protein synthesis and degradation. Consistently, overexpression of SELENOW in vivo and in vitro alleviated the muscle and myotube atrophy induced by DEX. SELENOW played a role in age-related sarcopenia and regulated the genes associated with aging. Together, our study uncovered the function of SELENOW in age-related sarcopenia and provides promising evidence for the prevention and treatment of sarcopenia.
Assuntos
Camundongos Knockout , Complexo de Endopeptidases do Proteassoma , Biossíntese de Proteínas , Sarcopenia , Selenoproteína W , Ubiquitina , Animais , Complexo de Endopeptidases do Proteassoma/metabolismo , Camundongos , Sarcopenia/metabolismo , Sarcopenia/genética , Sarcopenia/patologia , Ubiquitina/metabolismo , Selenoproteína W/genética , Selenoproteína W/metabolismo , Músculo Esquelético/metabolismo , Músculo Esquelético/patologia , Músculo Esquelético/efeitos dos fármacos , Proteínas rac1 de Ligação ao GTP/metabolismo , Proteínas rac1 de Ligação ao GTP/genética , Dexametasona/farmacologia , Serina-Treonina Quinases TOR/metabolismo , Modelos Animais de Doenças , Atrofia Muscular/metabolismo , Atrofia Muscular/genética , Atrofia Muscular/patologia , Atrofia Muscular/induzido quimicamente , Envelhecimento/metabolismo , Masculino , Transdução de Sinais , NeuropeptídeosRESUMO
BACKGROUND: Dysferlin-deficient limb-girdle muscular dystrophy type 2B (Dysf) mice are notorious for their mild phenotype. Raising plasma total cholesterol (CHOL) via apolipoprotein E (ApoE) knockout (KO) drastically exacerbates muscle wasting in Dysf mice. However, dysferlinopathic patients have abnormally reduced plasma high-density lipoprotein cholesterol (HDL-C) levels. The current study aimed to determine whether HDL-C lowering can exacerbate the mild phenotype of dysferlin-null mice. METHODS: Human cholesteryl ester transfer protein (CETP), a plasma lipid transfer protein not found in mice that reduces HDL-C, and/or its optimal adapter protein human apolipoprotein B (ApoB), were overexpressed in Dysf mice. Mice received a 2% cholesterol diet from 2 months of age and characterized through ambulatory and hanging functional tests, plasma analyses, and muscle histology. RESULTS: CETP/ApoB expression in Dysf mice caused reduced HDL-C (54.5%) and elevated ratio of CHOL/HDL-C (181.3%) compared to control Dysf mice in plasma, but without raising CHOL. Compared to the severe muscle pathology found in high CHOL Dysf/ApoE double knockout mice, Dysf/CETP/ApoB mice did not show significant changes in ambulation, hanging capacity, increases in damaged area, collagen deposition, or decreases in cross-sectional area and healthy myofibre coverage. CONCLUSIONS: CETP/ApoB over-expression in Dysf mice decreases HDL-C without increasing CHOL or exacerbating muscle pathology. High CHOL or nonHDL-C caused by ApoE KO, rather than low HDL-C, likely lead to rodent muscular dystrophy phenotype humanization.
Assuntos
Apolipoproteínas E , Proteínas de Transferência de Ésteres de Colesterol , HDL-Colesterol , Disferlina , Camundongos Knockout , Distrofia Muscular do Cíngulo dos Membros , Animais , Humanos , Masculino , Camundongos , Apolipoproteínas B/sangue , Apolipoproteínas B/genética , Apolipoproteínas E/genética , Apolipoproteínas E/deficiência , Proteínas de Transferência de Ésteres de Colesterol/genética , Proteínas de Transferência de Ésteres de Colesterol/deficiência , HDL-Colesterol/sangue , Modelos Animais de Doenças , Disferlina/genética , Disferlina/deficiência , Músculo Esquelético/metabolismo , Músculo Esquelético/patologia , Atrofia Muscular/genética , Atrofia Muscular/patologia , Atrofia Muscular/metabolismo , Distrofia Muscular do Cíngulo dos Membros/genética , Distrofia Muscular do Cíngulo dos Membros/patologiaRESUMO
Muscle wasting is a universal hallmark of aging which is displayed by a wide range of organisms, although the causes and mechanisms of this phenomenon are not fully understood. We used Drosophila to characterize the phenomenon of spontaneous muscle fiber degeneration (SMFD) during aging. We found that SMFD occurs across diverse types of somatic muscles, progresses with chronological age, and positively correlates with functional muscle decline. Data from vital dyes and morphological markers imply that degenerative fibers most likely die by necrosis. Mechanistically, SMFD is driven by the damage resulting from muscle contractions, and the nervous system may play a significant role in this process. Our quantitative model of SMFD assessment can be useful in identifying and validating novel genetic factors that influence aging-related muscle wasting.
Assuntos
Envelhecimento , Estresse Mecânico , Animais , Envelhecimento/genética , Envelhecimento/fisiologia , Drosophila melanogaster/genética , Atrofia Muscular/genética , Atrofia Muscular/patologia , Atrofia Muscular/fisiopatologia , Atrofia Muscular/metabolismo , Fibras Musculares Esqueléticas/patologia , Fibras Musculares Esqueléticas/metabolismo , Contração MuscularRESUMO
Oxidative stress contributes to the loss of skeletal muscle mass and function in cancer cachexia. However, this outcome may be mitigated by an improved endogenous antioxidant defence system. Here, using the well-established oxidative stress-inducing muscle atrophy model of Lewis lung carcinoma (LLC) in 13-week-old male C57BL/6J mice, we demonstrate that extracellular superoxide dismutase (EcSOD) levels increase in the cachexia-prone extensor digitorum longus muscle. LLC transplantation significantly increased interleukin-1ß (IL-1ß) expression and release from extensor digitorum longus muscle fibres. Moreover, IL-1ß treatment of C2C12 myotubes increased NBR1, p62 phosphorylation at Ser351, Nrf2 nuclear translocation and EcSOD protein expression. Additional studies in vivo indicated that intramuscular IL-1ß injection is sufficient to stimulate EcSOD expression, which is prevented by muscle-specific knockout of p62 and Nrf2 (i.e. in p62 skmKO and Nrf2 skmKO mice, respectively). Finally, since an increase in circulating IL-1ß may lead to unwanted outcomes, we demonstrate that targeting this pathway at p62 is sufficient to drive muscle EcSOD expression in an Nrf2-dependent manner. In summary, cancer cachexia increases EcSOD expression in extensor digitorum longus muscle via muscle-derived IL-1ß-induced upregulation of p62 phosphorylation and Nrf2 activation. These findings provide further mechanistic evidence for the therapeutic potential of p62 and Nrf2 to mitigate cancer cachexia-induced muscle atrophy. KEY POINTS: Oxidative stress plays an important role in muscle atrophy during cancer cachexia. EcSOD, which mitigates muscle loss during oxidative stress, is upregulated in 13-week-old male C57BL/6J mice of extensor digitorum longus muscles during cancer cachexia. Using mouse and cellular models, we demonstrate that cancer cachexia promotes muscle EcSOD protein expression via muscle-derived IL-1ß-dependent stimulation of the NBR1-p62-Nrf2 signalling pathway. These results provide further evidence for the potential therapeutic targeting of the NBR1-p62-Nrf2 signalling pathway downstream of IL-1ß to mitigate cancer cachexia-induced muscle atrophy.
Assuntos
Caquexia , Interleucina-1beta , Camundongos Endogâmicos C57BL , Músculo Esquelético , Fator 2 Relacionado a NF-E2 , Transdução de Sinais , Superóxido Dismutase , Animais , Fator 2 Relacionado a NF-E2/metabolismo , Fator 2 Relacionado a NF-E2/genética , Caquexia/metabolismo , Caquexia/etiologia , Caquexia/genética , Masculino , Interleucina-1beta/metabolismo , Músculo Esquelético/metabolismo , Camundongos , Superóxido Dismutase/metabolismo , Superóxido Dismutase/genética , Proteína Sequestossoma-1/metabolismo , Proteína Sequestossoma-1/genética , Carcinoma Pulmonar de Lewis/metabolismo , Carcinoma Pulmonar de Lewis/complicações , Carcinoma Pulmonar de Lewis/genética , Atrofia Muscular/metabolismo , Atrofia Muscular/etiologia , Atrofia Muscular/genética , Camundongos Knockout , Estresse OxidativoRESUMO
Skeletal muscle atrophy is a morbidity and mortality risk factor that happens with disuse, chronic disease, and aging. The tissue remodeling that happens during recovery from atrophy or injury involves changes in different cell types such as muscle fibers, and satellite and immune cells. Here, we show that the previously uncharacterized gene and protein Zfp697 is a damage-induced regulator of muscle remodeling. Zfp697/ZNF697 expression is transiently elevated during recovery from muscle atrophy or injury in mice and humans. Sustained Zfp697 expression in mouse muscle leads to a gene expression signature of chemokine secretion, immune cell recruitment, and extracellular matrix remodeling. Notably, although Zfp697 is expressed in several cell types in skeletal muscle, myofiber-specific Zfp697 genetic ablation in mice is sufficient to hinder the inflammatory and regenerative response to muscle injury, compromising functional recovery. We show that Zfp697 is an essential mediator of the interferon gamma response in muscle cells and that it functions primarily as an RNA-interacting protein, with a very high number of miRNA targets. This work identifies Zfp697 as an integrator of cell-cell communication necessary for tissue remodeling and regeneration.
Assuntos
Músculo Esquelético , Proteínas de Ligação a RNA , Animais , Camundongos , Músculo Esquelético/metabolismo , Músculo Esquelético/patologia , Proteínas de Ligação a RNA/metabolismo , Proteínas de Ligação a RNA/genética , Humanos , Inflamação/metabolismo , Inflamação/patologia , Inflamação/genética , Camundongos Knockout , Atrofia Muscular/metabolismo , Atrofia Muscular/genética , Atrofia Muscular/patologia , MicroRNAs/genética , MicroRNAs/metabolismo , Camundongos Endogâmicos C57BL , Interferon gama/metabolismoRESUMO
Skeletal muscle atrophy, characterized by diminished muscle strength and mass, arises from various causes, including malnutrition, aging, nerve damage, and disease-related secondary atrophy. Aging markedly escalates the prevalence of sarcopenia. Concurrently, the incidence of muscle atrophy significantly rises among patients with chronic ailments such as heart failure, diabetes, and chronic obstructive pulmonary disease (COPD). Epigenetics plays a pivotal role in skeletal muscle atrophy. Aging elevates methylation levels in the promoter regions of specific genes within muscle tissues. This aberrant methylation is similarly observed in conditions like diabetes, neurological disorders, and cardiovascular diseases. This study aims to explore the relationship between epigenetics and skeletal muscle atrophy, thereby enhancing the understanding of its pathogenesis and uncovering novel therapeutic strategies.
Assuntos
Metilação de DNA , Epigênese Genética , Músculo Esquelético , Atrofia Muscular , Humanos , Atrofia Muscular/genética , Atrofia Muscular/patologia , Atrofia Muscular/metabolismo , Músculo Esquelético/patologia , Músculo Esquelético/metabolismo , Animais , Envelhecimento/genética , Envelhecimento/patologiaRESUMO
RATIONALE: Allan-Herndon-Dudley syndrome (AHDS) results from a pathogenic variant in the hemizygous subunit of the SLC16A2 gene, which encodes monocarboxylate transporter 8 and follows an X-linked recessive pattern. AHDS manifests as neuropsychomotor developmental delay, intellectual disability, movement disorders, and thyroid hormone abnormalities. It is frequently misdiagnosed as cerebral palsy or hypothyroidism. PATIENT CONCERNS: A 9-month-old male infant exhibited poor head control, hypodynamia, motor retardation, hypertonic limbs, and thyroid abnormalities. Despite levothyroxine supplementation and rehabilitation therapy, no improvements were observed. Whole-exome sequencing identified a novel nonsense mutation in SLC16A2 (c.124Gâ >â T, p.E42X), which unequivocally established the diagnosis. DIAGNOSES: AHDS was confirmed. INTERVENTIONS: Levothyroxine treatment commenced early in infancy, followed by 3 months of rehabilitation therapy, starting at 5 months of age. The combined administration of levothyroxine and methimazole was initiated at 1 year and 10 months of age, respectively. OUTCOMES: While improvements were noted in thyroid hormone levels, neurological developmental delays persisted. LESSONS: AHDS should be considered in patients presenting with atypical neurological features and thyroid hormone abnormalities such as elevated triiodothyronine and decreased thyroxine levels. The early utilization of exome sequencing aids in prompt diagnosis. The identified SLC16A2 nonsense mutation correlates with severe neurological phenotypes and adds to the spectrum of genetic variations associated with AHDS.
Assuntos
Códon sem Sentido , Transportadores de Ácidos Monocarboxílicos , Hipotonia Muscular , Atrofia Muscular , Simportadores , Humanos , Masculino , Transportadores de Ácidos Monocarboxílicos/genética , Lactente , Hipotonia Muscular/genética , Hipotonia Muscular/diagnóstico , Simportadores/genética , Atrofia Muscular/genética , Atrofia Muscular/diagnóstico , Fenótipo , Deficiência Intelectual Ligada ao Cromossomo X/genética , Deficiência Intelectual Ligada ao Cromossomo X/diagnóstico , Tiroxina/uso terapêutico , Hipertonia Muscular/genética , Hipertonia Muscular/diagnóstico , Sequenciamento do Exoma/métodosRESUMO
BACKGROUND: Tumour-induced skeletal muscle wasting in the context of cancer cachexia is a condition with profound implications for patient survival. The loss of muscle mass is a significant clinical obstacle and is linked to reduced tolerance to chemotherapy and increased frailty. Understanding the molecular mechanisms driving muscle atrophy is crucial for the design of new therapeutics. METHODS: Lewis lung carcinoma tumours were utilized to induce cachexia and muscle atrophy in mice. Single-nucleus libraries of the tibialis anterior (TA) muscle from tumour-bearing mice and their non-tumour-bearing controls were constructed using 10X Genomics applications following the manufacturer's guidelines. RNA sequencing results were analysed with Cell Ranger software and the Seurat R package. Oxygen consumption of mitochondria isolated from TA muscle was measured using an Oroboros O2k-FluoRespirometer. Mouse primary myotubes were treated with a recombinant ectodysplasin A2 (EDA-A2) protein to activate EDA-A2 receptor (EDA2R) signalling and study changes in gene expression and oxygen consumption. RESULTS: Tumour-bearing mice were sacrificed while exhibiting moderate cachexia. Average TA muscle weight was reduced by 11% (P = 0.0207) in these mice. A total of 12 335 nuclei, comprising 6422 nuclei from the control group and 5892 nuclei from atrophying muscles, were studied. The analysis of single-nucleus transcriptomes identified distinct myonuclear gene signatures and a shift towards type IIb myonuclei. Muscle atrophy-related genes, including Atrogin1, MuRF1 and Eda2r, were upregulated in these myonuclei, emphasizing their crucial roles in muscle wasting. Gene set enrichment analysis demonstrated that EDA2R activation and tumour inoculation led to similar expression patterns in muscle cells, including the stimulation of nuclear factor-kappa B, Janus kinase-signal transducer and activator of transcription and transforming growth factor-beta pathways and the suppression of myogenesis and oxidative phosphorylation. Muscle oxidative metabolism was suppressed by both tumours and EDA2R activation. CONCLUSIONS: This study identified tumour-induced transcriptional changes in muscle tissue at single-nucleus resolution and highlighted the negative impact of tumours on oxidative metabolism. These findings contribute to a deeper understanding of the molecular mechanisms underlying muscle wasting.
Assuntos
Atrofia Muscular , Transcriptoma , Animais , Camundongos , Atrofia Muscular/metabolismo , Atrofia Muscular/genética , Músculo Esquelético/metabolismo , Músculo Esquelético/patologia , Proteólise , Carcinoma Pulmonar de Lewis/metabolismo , Carcinoma Pulmonar de Lewis/genética , Carcinoma Pulmonar de Lewis/patologia , Modelos Animais de Doenças , Caquexia/metabolismo , Caquexia/genética , Caquexia/etiologia , MasculinoRESUMO
PURPOSE OF THE REVIEW: Cancer-associated cachexia is a wasting syndrome entailing loss in body mass and a shortened life expectancy. There is currently no effective treatment to abrogate this syndrome, which leads to 20-30% of deaths in patients with cancer. While there have been advancements in defining signaling factors/pathways in cancer-induced muscle wasting, targeting the same in the clinic has not been as successful. Krüppel-like factor 10 (KLF10), a transcription factor implicated in muscle regulation, is regulated by the transforming growth factor-beta signaling pathway. This review proposes KLF10 as a potential convergence point of diverse signaling pathways involved in muscle wasting. RECENT FINDINGS: KLF10 was discovered as a target of transforming growth factor-beta decades ago but more recently it has been shown that deletion of KLF10 rescues cancer-induced muscle wasting. Moreover, KLF10 has also been shown to bind key atrophy genes associated with muscle atrophy in vitro . SUMMARY: There is an elevated need to explore targets in cachexia, which will successfully translate into the clinic. Investigating a convergence point downstream of multiple signaling pathways might hold promise in developing effective therapies for cachexia.
Assuntos
Caquexia , Fatores de Transcrição de Resposta de Crescimento Precoce , Fatores de Transcrição Kruppel-Like , Neoplasias , Transdução de Sinais , Caquexia/etiologia , Caquexia/genética , Caquexia/fisiopatologia , Humanos , Fatores de Transcrição Kruppel-Like/genética , Neoplasias/complicações , Fatores de Transcrição de Resposta de Crescimento Precoce/genética , Atrofia Muscular/genética , Fator de Crescimento Transformador beta/metabolismo , Músculo Esquelético/metabolismoRESUMO
The dystrophin protein has well-characterized roles in force transmission and maintaining membrane integrity during muscle contraction. Studies have reported decreased expression of dystrophin in atrophying muscles during wasting conditions, and that restoration of dystrophin can attenuate atrophy, suggesting a role in maintaining muscle mass. Phosphorylation of S3059 within the cysteine-rich region of dystrophin enhances binding between dystrophin and ß-dystroglycan, and mimicking phosphorylation at this site by site-directed mutagenesis attenuates myotube atrophy in vitro. To determine whether dystrophin phosphorylation can attenuate muscle wasting in vivo, CRISPR-Cas9 was used to generate mice with whole body mutations of S3059 to either alanine (DmdS3059A) or glutamate (DmdS3059E), to mimic a loss of, or constitutive phosphorylation of S3059, on all endogenous dystrophin isoforms, respectively. Sciatic nerve transection was performed on these mice to determine whether phosphorylation of dystrophin S3059 could attenuate denervation atrophy. At 14 days post denervation, atrophy of tibialis anterior (TA) but not gastrocnemius or soleus muscles, was partially attenuated in DmdS3059E mice relative to WT mice. Attenuation of atrophy was associated with increased expression of ß-dystroglycan in TA muscles of DmdS3059E mice. Dystrophin S3059 phosphorylation can partially attenuate denervation-induced atrophy, but may have more significant impact in less severe modes of muscle wasting.
Assuntos
Distrofina , Músculo Esquelético , Atrofia Muscular , Animais , Fosforilação , Camundongos , Atrofia Muscular/metabolismo , Atrofia Muscular/patologia , Atrofia Muscular/genética , Músculo Esquelético/metabolismo , Músculo Esquelético/inervação , Músculo Esquelético/patologia , Distrofina/metabolismo , Distrofina/genética , Masculino , Denervação Muscular/métodos , Camundongos Endogâmicos C57BLRESUMO
Skeletal muscular atrophy is a complex disease involving a large number of gene expression regulatory networks and various biological processes. Despite extensive research on this topic, its underlying mechanisms remain elusive, and effective therapeutic approaches are yet to be established. Recent studies have shown that epigenetics play an important role in regulating skeletal muscle atrophy, influencing the expression of numerous genes associated with this condition through the addition or removal of certain chemical modifications at the molecular level. This review article comprehensively summarizes the different types of modifications to DNA, histones, RNA, and their known regulators. We also discuss how epigenetic modifications change during the process of skeletal muscle atrophy, the molecular mechanisms by which epigenetic regulatory proteins control skeletal muscle atrophy, and assess their translational potential. The role of epigenetics on muscle stem cells is also highlighted. In addition, we propose that alternative splicing interacts with epigenetic mechanisms to regulate skeletal muscle mass, offering a novel perspective that enhances our understanding of epigenetic inheritance's role and the regulatory network governing skeletal muscle atrophy. Collectively, advancements in the understanding of epigenetic mechanisms provide invaluable insights into the study of skeletal muscle atrophy. Moreover, this knowledge paves the way for identifying new avenues for the development of more effective therapeutic strategies and pharmaceutical interventions.
Assuntos
Epigênese Genética , Músculo Esquelético , Atrofia Muscular , Humanos , Atrofia Muscular/genética , Atrofia Muscular/metabolismo , Atrofia Muscular/patologia , Músculo Esquelético/patologia , Músculo Esquelético/metabolismo , Animais , Histonas/metabolismo , Histonas/genética , Metilação de DNA/genética , Processamento Alternativo/genéticaRESUMO
BACKGROUND: Amyotrophic lateral sclerosis (ALS) is characterized by progressive motor neuron (MN) degeneration, leading to neuromuscular junction (NMJ) dismantling and severe muscle atrophy. The nuclear receptor interaction protein (NRIP) functions as a multifunctional protein. It directly interacts with calmodulin or α-actinin 2, serving as a calcium sensor for muscle contraction and maintaining sarcomere integrity. Additionally, NRIP binds with the acetylcholine receptor (AChR) for NMJ stabilization. Loss of NRIP in muscles results in progressive motor neuron degeneration with abnormal NMJ architecture, resembling ALS phenotypes. Therefore, we hypothesize that NRIP could be a therapeutic factor for ALS. METHODS: We used SOD1 G93A mice, expressing human SOD1 with the ALS-linked G93A mutation, as an ALS model. An adeno-associated virus vector encoding the human NRIP gene (AAV-NRIP) was generated and injected into the muscles of SOD1 G93A mice at 60 days of age, before disease onset. Pathological and behavioral changes were measured to evaluate the therapeutic effects of AAV-NRIP on the disease progression of SOD1 G93A mice. RESULTS: SOD1 G93A mice exhibited lower NRIP expression than wild-type mice in both the spinal cord and skeletal muscle tissues. Forced NRIP expression through AAV-NRIP intramuscular injection was observed in skeletal muscles and retrogradely transduced into the spinal cord. AAV-NRIP gene therapy enhanced movement distance and rearing frequencies in SOD1 G93A mice. Moreover, AAV-NRIP increased myofiber size and slow myosin expression, ameliorated NMJ degeneration and axon terminal denervation at NMJ, and increased the number of α-motor neurons (α-MNs) and compound muscle action potential (CMAP) in SOD1 G93A mice. CONCLUSIONS: AAV-NRIP gene therapy ameliorates muscle atrophy, motor neuron degeneration, and axon terminal denervation at NMJ, leading to increased NMJ transmission and improved motor functions in SOD1 G93A mice. Collectively, AAV-NRIP could be a potential therapeutic drug for ALS.
Assuntos
Esclerose Lateral Amiotrófica , Dependovirus , Modelos Animais de Doenças , Terapia Genética , Camundongos Transgênicos , Neurônios Motores , Atrofia Muscular , Animais , Esclerose Lateral Amiotrófica/genética , Esclerose Lateral Amiotrófica/terapia , Esclerose Lateral Amiotrófica/metabolismo , Esclerose Lateral Amiotrófica/patologia , Terapia Genética/métodos , Atrofia Muscular/genética , Atrofia Muscular/terapia , Atrofia Muscular/metabolismo , Atrofia Muscular/patologia , Neurônios Motores/metabolismo , Neurônios Motores/patologia , Dependovirus/genética , Camundongos , Humanos , Músculo Esquelético/metabolismo , Músculo Esquelético/patologia , Junção Neuromuscular/metabolismo , Junção Neuromuscular/patologia , Vetores Genéticos/administração & dosagem , Degeneração Neural/genética , Degeneração Neural/terapia , Masculino , Superóxido Dismutase-1/genética , Superóxido Dismutase-1/metabolismoRESUMO
Muscular atrophy is a complex catabolic condition that develops due to several inflammatory-related disorders, resulting in muscle loss. Tumor necrosis factor alpha (TNF-α) is believed to be one of the leading factors that drive inflammatory response and its progression. Until now, the link between inflammation and muscle wasting has been thoroughly investigated, and the non-coding RNA machinery is a potential connection between the candidates. This study aimed to identify specific miRNAs for muscular atrophy induced by TNF-α in the C2C12 murine myotube model. The difference in expression of fourteen known miRNAs and two newly identified miRNAs was recorded by next-generation sequencing between normal muscle cells and treated myotubes. After validation, we confirmed the difference in the expression of one novel murine miRNA (nov-mmu-miRNA-1) under different TNF-α-inducing conditions. Functional bioinformatic analyses of nov-mmu-miRNA-1 revealed the potential association with inflammation and muscle atrophy. Our results suggest that nov-mmu-miRNA-1 may trigger inflammation and muscle wasting by the downregulation of LIN28A/B, an anti-inflammatory factor in the let-7 family. Therefore, TNF-α is involved in muscle atrophy through the modulation of the miRNA cellular machinery. Here, we describe for the first time and propose a mechanism for the newly discovered miRNA, nov-mmu-miRNA-1, which may regulate inflammation and promote muscle atrophy.
Assuntos
MicroRNAs , Atrofia Muscular , Fator de Necrose Tumoral alfa , Animais , MicroRNAs/genética , MicroRNAs/metabolismo , Camundongos , Fator de Necrose Tumoral alfa/metabolismo , Fator de Necrose Tumoral alfa/genética , Atrofia Muscular/genética , Atrofia Muscular/metabolismo , Atrofia Muscular/patologia , Atrofia Muscular/induzido quimicamente , Linhagem Celular , Músculo Esquelético/metabolismo , Músculo Esquelético/patologia , Fibras Musculares Esqueléticas/metabolismo , Fibras Musculares Esqueléticas/patologia , Fibras Musculares Esqueléticas/efeitos dos fármacos , Regulação da Expressão Gênica/efeitos dos fármacos , Sequenciamento de Nucleotídeos em Larga EscalaRESUMO
Breast cancer is the type of cancer with the highest prevalence in women worldwide. Skeletal muscle atrophy is an important prognostic factor in women diagnosed with breast cancer. This atrophy stems from disrupted skeletal muscle homeostasis, triggered by diminished anabolic signalling and heightened inflammatory conditions, culminating in an upregulation of skeletal muscle proteolysis gene expression. The importance of delving into research on modulators of skeletal muscle atrophy, such as microRNAs (miRNAs), which play a crucial role in regulating cellular signalling pathways involved in skeletal muscle protein synthesis and degradation, has been recognised. This holds true for conditions of homeostasis as well as pathologies like cancer. However, the determination of specific miRNAs that modulate skeletal muscle atrophy in breast cancer conditions has not yet been explored. In this narrative review, we aim to identify miRNAs that could directly or indirectly influence skeletal muscle atrophy in breast cancer models to gain an updated perspective on potential therapeutic targets that could be modulated through resistance exercise training, aiming to mitigate the loss of skeletal muscle mass in breast cancer patients.
Assuntos
Neoplasias da Mama , MicroRNAs , Músculo Esquelético , Atrofia Muscular , Humanos , MicroRNAs/genética , MicroRNAs/metabolismo , Neoplasias da Mama/genética , Neoplasias da Mama/patologia , Neoplasias da Mama/metabolismo , Feminino , Atrofia Muscular/metabolismo , Atrofia Muscular/genética , Atrofia Muscular/patologia , Atrofia Muscular/etiologia , Músculo Esquelético/metabolismo , Músculo Esquelético/patologia , Animais , Desenvolvimento Muscular/genéticaRESUMO
Loss of muscle mass and function induced by sepsis contributes to physical inactivity and disability in intensive care unit patients. Limiting skeletal muscle deconditioning may thus be helpful in reducing the long-term effect of muscle wasting in patients. We tested the hypothesis that invalidation of the myostatin gene, which encodes a powerful negative regulator of skeletal muscle mass, could prevent or attenuate skeletal muscle wasting and improve survival of septic mice. Sepsis was induced by caecal ligature and puncture (CLP) in 13-week-old C57BL/6J wild-type and myostatin knock-out male mice. Survival rates were similar in wild-type and myostatin knock-out mice seven days after CLP. Loss in muscle mass was also similar in wild-type and myostatin knock-out mice 4 and 7 days after CLP. The loss in muscle mass was molecularly supported by an increase in the transcript level of E3-ubiquitin ligases and autophagy-lysosome markers. This transcriptional response was blunted in myostatin knock-out mice. No change was observed in the protein level of markers of the anabolic insulin/IGF1-Akt-mTOR pathway. Muscle strength was similarly decreased in wild-type and myostatin knock-out mice 4 and 7 days after CLP. This was associated with a modified expression of genes involved in ion homeostasis and excitation-contraction coupling, suggesting that a long-term functional recovery following experimental sepsis may be impaired by a dysregulated expression of molecular determinants of ion homeostasis and excitation-contraction coupling. In conclusion, myostatin gene invalidation does not provide any benefit in preventing skeletal muscle mass loss and strength in response to experimental sepsis. KEY POINTS: Survival rates are similar in wild-type and myostatin knock-out mice seven days after the induction of sepsis. Loss in muscle mass and muscle strength are similar in wild-type and myostatin knock-out mice 4 and 7 days after the induction of an experimental sepsis. Despite evidence of a transcriptional regulation, the protein level of markers of the anabolic insulin/IGF1-Akt-mTOR pathway remained unchanged. RT-qPCR analysis of autophagy-lysosome pathway markers indicates that activity of the pathway may be altered by experimental sepsis in wild-type and myostatin knock-out mice. Experimental sepsis induces greater variations in the mRNA levels of wild-type mice than those of myostatin knock-out mice, without providing any significant catabolic resistance or functional benefits.
Assuntos
Músculo Esquelético , Miostatina , Sepse , Animais , Masculino , Camundongos , Autofagia , Camundongos Endogâmicos C57BL , Camundongos Knockout , Força Muscular , Músculo Esquelético/metabolismo , Atrofia Muscular/genética , Atrofia Muscular/metabolismo , Miostatina/genética , Miostatina/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Proteínas Proto-Oncogênicas c-akt/genética , Sepse/genética , Sepse/metabolismo , Serina-Treonina Quinases TOR/metabolismo , Serina-Treonina Quinases TOR/genéticaRESUMO
Mitochondria play a central role in muscle metabolism and function. A unique family of iron-sulfur proteins, termed CDGSH Iron Sulfur Domain-containing (CISD/NEET) proteins, support mitochondrial function in skeletal muscles. The abundance of these proteins declines during aging leading to muscle degeneration. Although the function of the outer mitochondrial CISD/NEET proteins, CISD1/mitoNEET and CISD2/NAF-1, has been defined in skeletal muscle cells, the role of the inner mitochondrial CISD protein, CISD3/MiNT, is currently unknown. Here, we show that CISD3 deficiency in mice results in muscle atrophy that shares proteomic features with Duchenne muscular dystrophy. We further reveal that CISD3 deficiency impairs the function and structure of skeletal muscles, as well as their mitochondria, and that CISD3 interacts with, and donates its [2Fe-2S] clusters to, complex I respiratory chain subunit NADH Ubiquinone Oxidoreductase Core Subunit V2 (NDUFV2). Using coevolutionary and structural computational tools, we model a CISD3-NDUFV2 complex with proximal coevolving residue interactions conducive of [2Fe-2S] cluster transfer reactions, placing the clusters of the two proteins 10 to 16 Å apart. Taken together, our findings reveal that CISD3/MiNT is important for supporting the biogenesis and function of complex I, essential for muscle maintenance and function. Interventions that target CISD3 could therefore impact different muscle degeneration syndromes, aging, and related conditions.
Assuntos
Complexo I de Transporte de Elétrons , Proteínas Mitocondriais , Músculo Esquelético , Animais , Músculo Esquelético/metabolismo , Músculo Esquelético/patologia , Camundongos , Complexo I de Transporte de Elétrons/metabolismo , Complexo I de Transporte de Elétrons/genética , Proteínas Mitocondriais/metabolismo , Proteínas Mitocondriais/genética , Mitocôndrias/metabolismo , Proteínas Ferro-Enxofre/metabolismo , Proteínas Ferro-Enxofre/genética , Camundongos Knockout , Mitocôndrias Musculares/metabolismo , Humanos , Atrofia Muscular/metabolismo , Atrofia Muscular/patologia , Atrofia Muscular/genética , Distrofia Muscular de Duchenne/metabolismo , Distrofia Muscular de Duchenne/patologia , Distrofia Muscular de Duchenne/genéticaRESUMO
BACKGROUND: The rate and magnitude of skeletal muscle wasting after severe spinal cord injury (SCI) exceeds most other disuse conditions. Assessing the time course of molecular changes can provide insight into the progression of muscle wasting post-SCI. The goals of this study were (1) to identify potential targets that may prevent the pathologic features of SCI in soleus muscles and (2) to establish therapeutic windows for treating these pathologic changes. METHODS: Four-month-old Sprague-Dawley male rats received T9 laminectomy (SHAM surgery) or severe contusion SCI. Hindlimb locomotor function was assessed weekly, with soleus muscles obtained 1 week, 2 weeks, 1 month and 3 months post-surgery (n = 6-7 per group per timepoint). RNA was extracted from muscles for bulk RNA-sequencing analysis (n = 3-5 per group per timepoint). Differentially expressed genes (DEGs) were evaluated between age-matched SHAM and SCI animals. Myofiber size, muscle fibre type and fibrosis were assessed on contralateral muscles. RESULTS: SCI produced immediate and persistent hindlimb paralysis, with Basso-Beattie-Bresnahan locomotor scores remaining below 7 throughout the study, contributing to a progressive 25-50% lower soleus mass and myofiber atrophy versus SHAM (P < 0.05 at all timepoints). Transcriptional comparisons of SCI versus SHAM resulted in 184 DEGs (1 week), 436 DEGs (2 weeks), 133 DEGs (1 month) and 1200 DEGs (3 months). Upregulated atrophy-related genes included those associated with cell senescence, nuclear factor kappa B, ubiquitin proteasome and unfolded protein response pathways, along with upregulated genes that negatively influence muscle growth through the transforming growth factor beta pathway and inhibition of insulin-like growth factor-I/Akt/mechanistic target of rapamycin and p38/mitogen-activated protein kinase signalling. Genes associated with extracellular matrix (ECM), including collagens, collagen crosslinkers, proteoglycans and those regulating ECM integrity, were enriched within upregulated DEGs at 1 week but subsequently downregulated at 2 weeks and 3 months and were accompanied by >50% higher ECM areas and hydroxyproline levels in SCI muscles (P < 0.05). Myofiber remodelling genes were enriched in upregulated DEGs at 2 weeks and 1 month and were downregulated at 3 months. Genes that regulate neuromuscular junction remodelling were evident in muscles post-SCI, along with slow-to-fast fibre-type shifts: 1 week and 2 weeks SCI muscles were composed of 90% myosin heavy chain (MHC) type I fibres, which decreased to only 16% at 3 months and were accompanied by 50% fibres containing MHC IIX (P < 0.05). Metabolism genes were enriched in upregulated DEGs at 1 month and were further enriched at 3 months. CONCLUSIONS: Our results substantiate many known pathologic features of SCI-induced wasting in rat skeletal muscle and identify a progressive and dynamic transcriptional landscape within the post-SCI soleus. Future studies are warranted to consider these therapeutic treatment windows when countering SCI muscle pathology.
Assuntos
Fibrose , Atrofia Muscular , Traumatismos da Medula Espinal , Animais , Traumatismos da Medula Espinal/complicações , Traumatismos da Medula Espinal/metabolismo , Traumatismos da Medula Espinal/patologia , Traumatismos da Medula Espinal/genética , Ratos , Atrofia Muscular/metabolismo , Atrofia Muscular/etiologia , Atrofia Muscular/patologia , Atrofia Muscular/genética , Masculino , Transcriptoma , Ratos Sprague-Dawley , Modelos Animais de Doenças , Músculo Esquelético/patologia , Músculo Esquelético/metabolismo , Perfilação da Expressão GênicaRESUMO
Muscle atrophy is a debilitating condition with various causes; while aging is one of these causes, reduced engagement in routine musclestrengthening activities also markedly contributes to muscle loss. Although extensive research has been conducted on microRNAs (miRNAs/miRs) and their associations with muscle atrophy, the roles played by miRNA precursors remain underexplored. The present study detected the upregulation of the miR206 precursor in cellfree (cf)RNA from the plasma of patients at risk of sarcopenia, and in cfRNAs from the muscles of mice subjected to muscle atrophy. Additionally, a decline in the levels of the miR6516 precursor was observed in mice with muscle atrophy. The administration of mimicmiR6516 to mice immobilized due to injury inhibited muscle atrophy by targeting and inhibiting cyclindependent kinase inhibitor 1b (Cdkn1b). Based on these results, the miR206 precursor appears to be a potential biomarker of muscle atrophy, whereas miR6516 shows promise as a therapeutic target to alleviate muscle deterioration in patients with muscle disuse and atrophy.
Assuntos
MicroRNAs , Atrofia Muscular , Transtornos Musculares Atróficos , Adulto , Idoso , Animais , Feminino , Humanos , Masculino , Camundongos , Pessoa de Meia-Idade , Biomarcadores , Modelos Animais de Doenças , MicroRNAs/genética , MicroRNAs/metabolismo , Músculo Esquelético/metabolismo , Músculo Esquelético/patologia , Atrofia Muscular/genética , Atrofia Muscular/metabolismo , Atrofia Muscular/patologia , Transtornos Musculares Atróficos/genética , Transtornos Musculares Atróficos/metabolismo , Transtornos Musculares Atróficos/patologia , Transtornos Musculares Atróficos/terapia , Sarcopenia/metabolismo , Sarcopenia/genética , Sarcopenia/patologia , Sarcopenia/terapiaRESUMO
Heterogeneous nuclear ribonucleoprotein U (hnRNPU) is known to play multiple biological roles by regulating transcriptional expression, RNA splicing, RNA stability, and chromatin structure in a tissue-dependent manner. The role of hnRNPU in skeletal muscle development and maintenance has not been previously evaluated. In this study, skeletal muscle specific hnRNPU knock out mice is utilized and evaluated skeletal muscle mass and immune cell infiltration through development. By 4 weeks, muscle-specific hnRNPU knockout mice revealed Ly6C+ monocyte infiltration into skeletal muscle, which preceded muscle atrophy. Canonical NF-kB signaling is activated in a myofiber-autonomous manner with hnRNPU repression. Inducible hnRNPU skeletal muscle knockout mice further demonstrated that deletion of hnRNPU in adulthood is sufficient to cause muscle atrophy, suggesting that hnRNPU's role in muscle maintenance is not during development alone. Treatment with salirasib, to inhibit proliferation of immune cells, prevents muscle atrophy in muscle-specific hnRNPU knock out mice, indicating that immune cell infiltration plays causal role in muscle atrophy of hnRNPU knock out mice. Overall, the findings suggest that loss of hnRNPU triggers muscle inflammation and activates NF-κB signaling in a cell-autonomous manner, culminating in muscle atrophy.