Depletion of the miR-34a “sponge” MALAT1 in aging skeletal muscle: Implications for age-related muscle loss

Abstract We have recently shown that increased levels of reactive oxygen species (ROS) in aging skeletal muscle are associated with increased expression of the senescence-associated microRNA miR-34a-5p (miR-34a). The histone deacetylase Sirt1 is a validated target of miR-34a, and miR-34a expression is induced by the tumor suppressor p53 which is itself stimulated by ROS. Long noncoding RNAs (lncRNAs) are known to function as “sponges” for microRNAs, but the role of such competing endogenous RNAs (ceRNA) in muscle aging is not well understood. We therefore examined in skeletal muscles of young (4-6 mos) and aged (22-24) male and female mice the expression of several lncRNAs that are predicted to bind miR-34a-5p in silico and whose predicted binding has been validated experimentally. Results indicate a significant decrease in lncRNA MALAT1 expression with aging. MALAT1 is known to be highly expressed during the later stages of myoblast differentiation and myotube maturation. We therefore treated C2C12 cells at 48 hrs with hydrogen peroxide (10 uM) and examined changes in MALAT1 expression. MALAT1 was significantly decreased with H2O2 treatment, whereas miR-34a is increased in C2C12 cells after hydrogen peroxide exposure. Age-related muscle atrophy mediated by ROS may therefore result in part from related mechanisms involving miR-34a activity: an increase in miR-34a targeting Sirt1 resulting from p53 activation and an increase in miR-34a bioavailability resulting from a decline in miR-34a “sponging” due to ceRNA MALAT1 depletion. These findings suggest that therapeutic interventions increasing MALAT1 expression in muscle may potentially enhance the preservation of muscle mass with aging.

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Role of Age-Related Mitochondrial Dysfunction in Sarcopenia

International Journal of Molecular Sciences ◽

10.3390/ijms21155236 ◽

2020 ◽

Vol 21 (15) ◽

pp. 5236 ◽

Cited By ~ 1

Author(s):

Evelyn Ferri ◽

Emanuele Marzetti ◽

Riccardo Calvani ◽

Anna Picca ◽

Matteo Cesari ◽

...

Keyword(s):

Skeletal Muscle ◽

Cellular Senescence ◽

Significant Loss ◽

Muscle Aging ◽

Age Related ◽

Mitochondrial Functions ◽

Health Quality ◽

Skeletal Muscle Aging ◽

And Function

Skeletal muscle aging is associated with a significant loss of skeletal muscle strength and power (i.e., dynapenia), muscle mass and quality of life, a phenomenon known as sarcopenia. This condition affects nearly one-third of the older population and is one of the main factors leading to negative health outcomes in geriatric patients. Notwithstanding the exact mechanisms responsible for sarcopenia are not fully understood, mitochondria have emerged as one of the central regulators of sarcopenia. In fact, there is a wide consensus on the assumption that the loss of mitochondrial integrity in myocytes is the main factor leading to muscle degeneration. Mitochondria are also key players in senescence. It has been largely proven that the modulation of mitochondrial functions can induce the death of senescent cells and that removal of senescent cells improves musculoskeletal health, quality, and function. In this review, the crosstalk among mitochondria, cellular senescence, and sarcopenia will be discussed with the aim to elucidate the role that the musculoskeletal cellular senescence may play in the onset of sarcopenia through the mediation of mitochondria.

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Zfp422 promotes skeletal muscle differentiation by regulating EphA7 to induce appropriate myoblast apoptosis

Cell Death and Differentiation ◽

10.1038/s41418-019-0448-9 ◽

2019 ◽

Vol 27 (5) ◽

pp. 1644-1659 ◽

Cited By ~ 1

Author(s):

Yaping Nie ◽

Shufang Cai ◽

Renqiang Yuan ◽

Suying Ding ◽

Xumeng Zhang ◽

...

Keyword(s):

Skeletal Muscle ◽

Zinc Finger ◽

Muscle Development ◽

Zinc Finger Protein ◽

Critical Role ◽

Muscle Differentiation ◽

C2c12 Cells ◽

Myoblast Differentiation ◽

Skeletal Muscle Differentiation ◽

Finger Protein

Abstract Zinc finger protein 422 (Zfp422) is a widely expressed zinc finger protein that serves as a transcriptional factor to regulate downstream gene expression, but until now, little is known about its roles in myogenesis. We found here that Zfp422 plays a critical role in skeletal muscle development and regeneration. It highly expresses in mouse skeletal muscle during embryonic development. Specific knockout of Zfp422 in skeletal muscle impaired embryonic muscle formation. Satellite cell-specific Zfp422 deletion severely inhibited muscle regeneration. Myoblast differentiation and myotube formation were suppressed in Zfp422-deleted C2C12 cells, isolated primary myoblasts, and satellite cells. Chromatin Immunoprecipitation Sequencing (ChIP-Seq) revealed that Zfp422 regulated ephrin type-A receptor 7 (EphA7) expression by binding an upstream 169-bp DNA sequence, which was proved to be an enhancer of EphA7. Knocking EphA7 down in C2C12 cells or deleting Zfp422 in myoblasts will inhibit cell apoptosis which is required for myoblast differentiation. These results indicate that Zfp422 is essential for skeletal muscle differentiation and fusion, through regulating EphA7 expression to maintain proper apoptosis.

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miR-1/206 downregulates splicing factor Srsf9 to promote C2C12 differentiation

Skeletal Muscle ◽

10.1186/s13395-019-0211-4 ◽

2019 ◽

Vol 9 (1) ◽

Cited By ~ 6

Author(s):

Kristen K. Bjorkman ◽

Massimo Buvoli ◽

Emily K. Pugach ◽

Michael M. Polmear ◽

Leslie A. Leinwand

Keyword(s):

Gene Expression ◽

Time Course ◽

C2c12 Cell ◽

Muscle Differentiation ◽

Protein Isoforms ◽

C2c12 Cells ◽

Therapeutic Interventions ◽

Splicing Factor ◽

Myoblast Differentiation ◽

Functional Link

Abstract Background Myogenesis is driven by specific changes in the transcriptome that occur during the different stages of muscle differentiation. In addition to controlled transcriptional transitions, several other post-transcriptional mechanisms direct muscle differentiation. Both alternative splicing and miRNA activity regulate gene expression and production of specialized protein isoforms. Importantly, disruption of either process often results in severe phenotypes as reported for several muscle diseases. Thus, broadening our understanding of the post-transcriptional pathways that operate in muscles will lay the foundation for future therapeutic interventions. Methods We employed bioinformatics analysis in concert with the well-established C2C12 cell system for predicting and validating novel miR-1 and miR-206 targets engaged in muscle differentiation. We used reporter gene assays to test direct miRNA targeting and studied C2C12 cells stably expressing one of the cDNA candidates fused to a heterologous, miRNA-resistant 3′ UTR. We monitored effects on differentiation by measuring fusion index, myotube area, and myogenic gene expression during time course differentiation experiments. Results Gene ontology analysis revealed a strongly enriched set of putative miR-1 and miR-206 targets associated with RNA metabolism. Notably, the expression levels of several candidates decreased during C2C12 differentiation. We discovered that the splicing factor Srsf9 is a direct target of both miRNAs during myogenesis. Persistent Srsf9 expression during differentiation impaired myotube formation and blunted induction of the early pro-differentiation factor myogenin as well as the late differentiation marker sarcomeric myosin, Myh8. Conclusions Our data uncover novel miR-1 and miR-206 cellular targets and establish a functional link between the splicing factor Srsf9 and myoblast differentiation. The finding that miRNA-mediated clearance of Srsf9 is a key myogenic event illustrates the coordinated and sophisticated interplay between the diverse components of the gene regulatory network.

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Distinct and additive effects of calorie restriction and rapamycin in aging skeletal muscle

10.1101/2021.05.28.446097 ◽

2021 ◽

Author(s):

Daniel J Ham ◽

Anastasiya Boersch ◽

Kathrin Chojnowska ◽

Shuo Lin ◽

Aurel B Leuchtmann ◽

...

Keyword(s):

Skeletal Muscle ◽

Calorie Restriction ◽

Expression Profiles ◽

Life Quality ◽

Gene Expression Profiles ◽

Nutrient Sensing ◽

Skeletal Muscle Function ◽

Muscle Gene Expression ◽

Muscle Aging ◽

Age Related

As global life expectancy continues to climb, maintaining skeletal muscle function is increasingly essential to ensure a good life quality for aging populations. Calorie restriction (CR) is the most potent and reproducible intervention to extend health and lifespan, but is largely unachievable in humans. Therefore, identification of 'CR mimetics' has received much attention. CR targets nutrient-sensing pathways centering on mTORC1. The mTORC1 inhibitor, rapamycin, has been proposed as a potential CR mimetic and is proven to counteract age-related muscle loss. Therefore, we tested whether rapamycin acts via similar mechanisms as CR to slow muscle aging. Contrary to our expectation, long-term CR and rapamycin-treated geriatric mice display distinct skeletal muscle gene expression profiles despite both conferring benefits to aging skeletal muscle. Furthermore, CR improved muscle integrity in a mouse with nutrient-insensitive sustained muscle mTORC1 activity and rapamycin provided additive benefits to CR in aging mouse muscles. Therefore, RM and CR exert distinct, compounding effects in aging skeletal muscle, opening the possibility of parallel interventions to counteract muscle aging.

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Molecular Regulation and Rejuvenation of Muscle Stem (Satellite) Cell Aging

The Indonesian Biomedical Journal ◽

10.18585/inabj.v7i2.73 ◽

2015 ◽

Vol 7 (2) ◽

pp. 73

Author(s):

Anna Meiliana ◽

Nurrani Mustika Dewi ◽

Andi Wijaya

Keyword(s):

Skeletal Muscle ◽

Stem Cells ◽

Stem Cell ◽

Satellite Cell ◽

Muscle Mass ◽

Satellite Cells ◽

Cell Function ◽

Muscle Stem Cell ◽

Muscle Aging ◽

Age Related

BACKGROUND: Age-related muscle loss leads to lack of muscle strength, resulting in reduced posture and mobility and an increased risk of falls, all of which contribute to a decrease in quality of life. Skeletal muscle regeneration is a complex process, which is not yet completely understood.CONTENT: Skeletal muscle undergoes a progressive age-related loss in mass and function. Preservation of muscle mass depends in part on satellite cells, the resident stem cells of skeletal muscle. Reduced satellite cell function may contribute to the age-associated decrease in muscle mass. Recent studies have delineated that the aging process in organ stem cells is largely caused by age-specific changes in the differentiated niches, and that regenerative outcomes often depend on the age of the niche, rather than on stem cell age. It is likely that epigenetic states will be better define such key satellite cell features as prolonged quiescence and lineage fidelity. It is also likely that DNA and histone modifications will underlie many of the changes in aged satellite cells that account for age-related declines in functionality and rejuvenation through exposure to the systemic environment.SUMMARY: Skeletal muscle aging results in a gradual loss of skeletal muscle mass, skeletal muscle function and regenerative capacity, which can lead to sarcopenia and increased mortality. Although the mechanisms underlying sarcopenia remain unclear, the skeletal muscle stem cell, or satellite cell, is required for muscle regeneration. Decreased muscle stem cell function in aging has long been shown to depend on altered environmental cues, whereas the contribution of intrinsic mechanisms remained less clear. Signals in the aged niche were shown to cause permanent defects in the ability of satellite cells to return to quiescence, ultimately also impairing the maintenance of self-renewing satellite cells. Therefore, only anti-aging strategies taking both factors, the stem cell niche and the stem cells per se, into consideration may ultimately be successful.KEYWORDS: satellite cell, muscle, aging, niche, regenerations

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A Study on Myogenesis by Regulation of Reactive Oxygen Species and Cytotoxic Activity by Selenium Nanoparticles

Antioxidants ◽

10.3390/antiox10111727 ◽

2021 ◽

Vol 10 (11) ◽

pp. 1727

Author(s):

Sang-Cheol Lee ◽

Na-Hyun Lee ◽

Kapil D. Patel ◽

Soo-Kyung Jun ◽

Jeong-Hui Park ◽

...

Keyword(s):

Reactive Oxygen Species ◽

Skeletal Muscle ◽

Contractile Activity ◽

Reactive Oxygen ◽

Selenium Nanoparticles ◽

C2c12 Cells ◽

Myoblast Differentiation ◽

Oxygen Species ◽

Protective Effects ◽

Intracellular Ros

Reactive oxygen species (ROS) are continuously produced by skeletal muscle during contractile activity and even at rest. However, the ROS generated from excessive exercise or traumatic damage may produce more ROS than can be neutralized by an antioxidant capacity, which can be harmful to muscle function. In particular, selenium is a known antioxidant that regulates physiological functions such as cell differentiation and anti-inflammatory function. In this study, we developed nano-sized antioxidative biomaterials using selenium to investigate the protective and differentiation effects against C2C12 myoblasts in an H2O2-induced oxidative stress environment. The selenium nanoparticles (SeNPs) were produced with a size of 35.6 ± 4.3 nm and showed antioxidant effects according to the 3,3′,5,5′-tetramethylbenzidine assay. Then, SeNPs were treated to C2C12 cells with or without H2O2. Our results showed that SeNPs reduced C2C12 apoptosis and intracellular ROS levels. Additionally, SeNPs effectively up-regulated in the presence of H2O2, MyoD, MyoG, α-actinin, and myosin heavy chain, which are well known to increase during myoblast differentiation as assayed by qRT-PCR, immunocytochemistry-staining, western blotting. These results demonstrate that SeNPs can accelerate differentiation with its protective effects from the ROS environment and can be applied to the treatment of skeletal muscle in a cellular redox environment.

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miR-1/206 down-regulates splicing factor Srsf9 to promote myogenesis

10.1101/691162 ◽

2019 ◽

Author(s):

Kristen K. Bjorkman ◽

Massimo Buvoli ◽

Emily K. Pugach ◽

Michael M. Polmear ◽

Leslie A. Leinwand

Keyword(s):

Gene Expression ◽

Time Course ◽

C2c12 Cell ◽

Muscle Differentiation ◽

Protein Isoforms ◽

C2c12 Cells ◽

Therapeutic Interventions ◽

Splicing Factor ◽

Myoblast Differentiation ◽

Functional Link

AbstractBackgroundMyogenesis is driven by specific changes in the transcriptome that occur during the different stages of muscle differentiation. In addition to controlled transcriptional transitions, several other post-transcriptional mechanisms direct muscle differentiation. Both alternative splicing and miRNA activity regulate gene expression and production of specialized protein isoforms. Importantly, disruption of either process often results in severe phenotypes as reported for several muscle diseases. Thus, broadening our understanding of the post-transcriptional pathways that operate in muscles will lay the foundation for future therapeutic interventions.MethodsWe employed bioinformatics analysis in concert with the well-established C2C12 cell system for predicting and validating novel miR-1 and miR-206 targets engaged in muscle differentiation. We used reporter gene assays to test direct miRNA targeting and studied C2C12 cells stably expressing one of the cDNA candidates fused to a heterologous, miRNA-resistant 3’ UTR. We monitored effects on differentiation by measuring fusion index, myotube area, and myogenic gene expression during time course differentiation experiments.ResultsGene ontology analysis revealed a strongly enriched set of putative miR-1 and miR-206 targets associated with RNA metabolism. Notably, the expression levels of several candidates decreased during C2C12 differentiation. We discovered that the splicing factor Srsf9 is a direct target of both miRNAs during myogenesis. Persistent Srsf9 expression during differentiation impaired myotube formation and blunted induction of the early pro-differentiation factor myogenin as well as the late differentiation marker sarcomeric myosin, Myh8.ConclusionsOur data uncover novel miR-1 and miR-206 cellular targets and establish a functional link between the splicing factor Srsf9 and myoblast differentiation. The finding that miRNA-mediated clearance of Srsf9 is a key myogenic event illustrates the coordinated and sophisticated interplay between the diverse components of the gene regulatory network.

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IRE1-XBP1 Pathway of the Unfolded Protein Response Is Required during Early Differentiation of C2C12 Myoblasts

International Journal of Molecular Sciences ◽

10.3390/ijms21010182 ◽

2019 ◽

Vol 21 (1) ◽

pp. 182 ◽

Cited By ~ 4

Author(s):

Yukako Tokutake ◽

Keita Yamada ◽

Satoko Hayashi ◽

Wataru Arai ◽

Takafumi Watanabe ◽

...

Keyword(s):

Skeletal Muscle ◽

Muscle Differentiation ◽

C2c12 Cells ◽

Myoblast Differentiation ◽

Skeletal Muscle Differentiation ◽

Cyclin Dependent Kinase ◽

Early Differentiation ◽

Unfolded Protein ◽

The Unfolded Protein Response ◽

Protein Response

In skeletal muscle, myoblast differentiation results in the formation of multinucleated myofibers. Although recent studies have shown that unfolded protein responses (UPRs) play an important role in intracellular remodeling and contribute to skeletal muscle differentiation, the involvement of IRE1–XBP1 signaling, a major UPR signaling pathway, remains unclear. This study aimed to investigate the effect of the IRE1–XBP1 pathway on skeletal muscle differentiation. In C2C12 cells, knockdown of IRE1 and XBP1 in cells remarkably suppressed differentiation. In addition, apoptosis and autophagy were dramatically enhanced in the XBP1-knockdown cells, highlighting the participation of IRE1–XBP1 in cell survival maintenance with differentiation stimuli during skeletal muscle differentiation. In myogenic cells, we demonstrated that the expression of CDK5 (cyclin-dependent kinase 5) is regulated by XBP1s, and we propose that XBP1 regulates the expression of MyoD family genes via the induction of CDK5. In conclusion, this study revealed that IRE1–XBP1 signaling plays critical roles in cell viability and the expression of differentiation-related genes in predifferentiated myoblasts and during the early differentiation phase.

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Exercise rescues mitochondrial coupling in aged skeletal muscle: a comparison of different modalities in preventing sarcopenia

Journal of Translational Medicine ◽

10.1186/s12967-021-02737-1 ◽

2021 ◽

Vol 19 (1) ◽

Author(s):

Colin Harper ◽

Venkatesh Gopalan ◽

Jorming Goh

Keyword(s):

Skeletal Muscle ◽

Mitochondrial Function ◽

Fiber Type ◽

Skeletal Muscle Function ◽

Atp Production ◽

Muscle Aging ◽

Age Related ◽

Key Factor ◽

Underlying Mechanisms ◽

Skeletal Muscle Aging

AbstractSkeletal muscle aging is associated with a decline in motor function and loss of muscle mass- a condition known as sarcopenia. The underlying mechanisms that drive this pathology are associated with a failure in energy generation in skeletal muscle, either from age-related decline in mitochondrial function, or from disuse. To an extent, lifelong exercise is efficacious in preserving the energetic properties of skeletal muscle and thus may delay the onset of sarcopenia. This review discusses the cellular and molecular changes in skeletal muscle mitochondria during the aging process and how different exercise modalities work to reverse these changes. A key factor that will be described is the efficiency of mitochondrial coupling—ATP production relative to O2 uptake in myocytes and how that efficiency is a main driver for age-associated decline in skeletal muscle function. With that, we postulate the most effective exercise modality and protocol for reversing the molecular hallmarks of skeletal muscle aging and staving off sarcopenia. Two other concepts pertinent to mitochondrial efficiency in exercise-trained skeletal muscle will be integrated in this review, including- mitophagy, the removal of dysfunctional mitochondrial via autophagy, as well as the implications of muscle fiber type changes with sarcopenia on mitochondrial function.

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Daily Oral Administration of Protease-Treated Royal Jelly Protects Against Denervation-Induced Skeletal Muscle Atrophy

Nutrients ◽

10.3390/nu12103089 ◽

2020 ◽

Vol 12 (10) ◽

pp. 3089

Author(s):

Tomohiko Shirakawa ◽

Aki Miyawaki ◽

Takuma Matsubara ◽

Nobuaki Okumura ◽

Hideto Okamoto ◽

...

Keyword(s):

Skeletal Muscle ◽

Muscle Atrophy ◽

Royal Jelly ◽

Muscle Metabolism ◽

Sebacic Acid ◽

C2c12 Cells ◽

Skeletal Muscle Atrophy ◽

Muscle Weight ◽

Age Related ◽

Myoblast Cells

Honeybees produce royal jelly (RJ) from their cephalic glands. Royal jelly is a source of nutrition for the queen honey bee throughout its lifespan and is also involved in fertility and longevity. Royal jelly has long been considered beneficial to human health. We recently observed that RJ delayed impairment of motor function during aging, affecting muscle fiber size. However, how RJ affects skeletal muscle metabolism and the functional component of RJ is as of yet unidentified. We demonstrate that feeding mice with RJ daily prevents a decrease in myofiber size following denervation without affecting total muscle weight. RJ did not affect atrophy-related genes but stimulated the expression of myogenesis-related genes, including IGF-1 and IGF receptor. Trans-10-hydroxy-2-decenoic acid (10H2DA) and 10-hydroxydecanoic acid (10HDAA), two major fatty acids contained in RJ. After ingestion, 10H2DA and 10HDAA are metabolized into 2-decenedioic acid (2DA) and sebacic acid (SA) respectively. We found that 10H2DA, 10HDAA, 2DA, and SA all regulated myogenesis of C2C12 cells, murine myoblast cells. These novel findings may be useful for potential preventative and therapeutic applications for muscle atrophy disease included in Sarcopenia, an age-related decline in skeletal muscle mass and strength.

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