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In the last decade, clear evidence has emerged that the cellular components of skeletal muscle are important sites for the release of proteins and peptides called "myokines", suggesting that skeletal muscle plays the role of a secretory organ. After their secretion by muscles, these factors serve many biological functions, including the exertion of complex autocrine, paracrine and/or endocrine effects. In sum, myokines affect complex multi-organ processes, such as skeletal muscle trophism, metabolism, angiogenesis and immunological response to different physiological (physical activity, aging, etc.) or pathological states (cachexia, dysmetabolic conditions, chronic inflammation, etc.). The aim of this review is to describe in detail a number of myokines that are, to varying degrees, involved in skeletal muscle aging processes and belong to the group of proteins present in the functional environment surrounding the muscle cell known as the "Niche". The particular myokines described are those that, acting both from within the cell and in an autocrine manner, have a defined relationship with the modulation of oxidative stress in muscle cells (mature or stem) involved in the regulatory (metabolic or regenerative) processes of muscle aging. Myostatin, IGF-1, NGF, S100 and irisin are examples of specific myokines that have peculiar features in their mechanisms of action. In particular, the potential role of one of the most recently characterized myokines-irisin, directly linked to an active lifestyle-in reducing if not reversing senescence-induced oxidative damage is discussed in terms of its possible application as an agent able to counteract the deleterious effects of muscle aging.
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Envelhecimento/metabolismo , Senescência Celular , Citocinas/metabolismo , Músculo Esquelético/metabolismo , HumanosRESUMO
Purines are nitrogen compounds consisting mainly of a nitrogen base of adenine (ABP) or guanine (GBP) and their derivatives: nucleosides (nitrogen bases plus ribose) and nucleotides (nitrogen bases plus ribose and phosphate). These compounds are very common in nature, especially in a phosphorylated form. There is increasing evidence that purines are involved in the development of different organs such as the heart, skeletal muscle and brain. When brain development is complete, some purinergic mechanisms may be silenced, but may be reactivated in the adult brain/muscle, suggesting a role for purines in regeneration and self-repair. Thus, it is possible that guanosine-5'-triphosphate (GTP) also acts as regulator during the adult phase. However, regarding GBP, no specific receptor has been cloned for GTP or its metabolites, although specific binding sites with distinct GTP affinity characteristics have been found in both muscle and neural cell lines. Finally, even if the cross regulation mechanisms between the two different purines (ABP and GBP) are still largely unknown, it is now possible to hypothesize the existence of specific signal paths for guanosine-based nucleotides that are capable of modulating the intensity and duration of the intracellular signal, particularly in excitable tissues such as brain and muscle.
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Guanosina/metabolismo , Nucleotídeos/metabolismo , Purinas/metabolismo , Encéfalo/metabolismo , Desenvolvimento Embrionário/fisiologia , Guanina/metabolismo , Nucleotídeos de Guanina/metabolismo , Guanosina Trifosfato/metabolismo , Humanos , Músculos/metabolismo , Sistema Nervoso/metabolismo , Nucleosídeos/metabolismo , Receptores Purinérgicos/metabolismoRESUMO
Satellite cells that reside on the myofibre surface are crucial for the muscle homeostasis and regeneration. Aging goes along with a less effective regeneration of skeletal muscle tissue mainly due to the decreased myogenic capability of satellite cells. This phenomenon impedes proper maintenance and contributes to the age-associated decline in muscle mass, known as sarcopenia. The myogenic potential impairment does not depend on a reduced myogenic cell number, but mainly on their difficulty to complete a differentiation program. The unbalanced production of reactive oxygen species in elderly people could be responsible for skeletal muscle impairments. microRNAs are conserved post-transcriptional regulators implicated in numerous biological processes including adult myogenesis. Here, we measure the ROS level and analyze myomiR (miR-1, miR-133b and miR-206) expression in human myogenic precursors obtained from Vastus lateralis of elderly and young subjects to provide the molecular signature responsible for the differentiation impairment of elderly activated satellite cells.
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Envelhecimento , Regulação da Expressão Gênica , MicroRNAs/genética , Desenvolvimento Muscular , Espécies Reativas de Oxigênio/metabolismo , Células Satélites de Músculo Esquelético/metabolismo , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Células Cultivadas , Humanos , Masculino , Sarcopenia/genética , Sarcopenia/metabolismo , Células Satélites de Músculo Esquelético/citologia , Adulto JovemRESUMO
BACKGROUND/AIMS: Extracellular GTP is able to modulate some specific functions in neuron, glia and muscle cell models as it has been demonstrated over the last two decades. In fact, extracellular GTP binds its specific plasma membrane binding sites and induces signal transduction via [Ca(2+)]i increase. We demonstrate, for the first time, that extracellular GTP is able to modulate cell swelling in M1-CCD cortical collecting duct epithelial cells via upregulation of aquaporin 5 (AQP5) expression. METHODS: We used videoimaging, immunocitochemistry, flow cytometry, confocal techniques, Western blotting and RT-PCR for protein and gene expression analysis, respectively. RESULTS: We demonstrate that AQP5 mRNA is up-regulated 7 h after the GTP exposure in the cell culture medium, and its protein level is increased after 12-24 h. We show that AQP5 is targeted to the plasma membrane of M1-CCD cells, where it facilitates cell swelling, and that the GTP-dependent AQP5 up-regulation occurs via [Ca(2+)]i increase. Indeed, GTP induces both oscillating and transient [Ca(2+)]i increase, and specifically the oscillating kinetic appears to be responsible for blocking cell cycle in the S-phase while the [Ca(2+)]i influx, with whatever kinetic, seems to be responsible for inducing AQP5 expression. CONCLUSION: The role of GTP as a regulator of AQP5-mediated water transport in renal cells is of great importance in the physiology of renal epithelia, due to its possible physiopathological implications. GTP-dependent AQP5 expression could act as osmosensor. In addition, the data presented here suggest that GTP might play the same role in other tissues where rapid water transport is required for cell volume regulation and maintenance of the homeostasis.
Assuntos
Aquaporina 5/biossíntese , Membrana Celular/metabolismo , Células Epiteliais/metabolismo , Guanosina Trifosfato/farmacologia , Túbulos Renais Coletores/metabolismo , Regulação para Cima/efeitos dos fármacos , Animais , Sinalização do Cálcio/efeitos dos fármacos , Linhagem Celular , Células Epiteliais/citologia , Túbulos Renais Coletores/citologia , CamundongosRESUMO
Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a demanding medical condition for patients and society. It has raised much more public awareness after the COVID-19 pandemic since ME/CFS and long-COVID patients share many clinical symptoms such as debilitating chronic fatigue. However, unlike long COVID, the etiopathology of ME/CFS remains a mystery despite several decades' research. This review moves from pathophysiology of ME/CFS through the compelling evidence and most interesting hypotheses. It focuses on the pathophysiology of skeletal muscle by proposing the hypothesis that skeletal muscle tissue offers novel opportunities for diagnosis and treatment of this syndrome and that new evidence can help resolve the long-standing debate on terminology.
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Síndrome de Fadiga Crônica , Humanos , Síndrome de Fadiga Crônica/diagnóstico , Síndrome de Fadiga Crônica/epidemiologia , Síndrome de COVID-19 Pós-Aguda , Pandemias , Músculo Esquelético/metabolismoRESUMO
Long COVID-19-related changes in physiology includes alterations in performing muscle work as fatigue. Data available do not allow us to define the usefulness of physical activity to attenuate long COVID-19 functional modifications. The present observational study investigates the effects of physical activity on the perception of fatigue, maximum power output, sleep, and cognitive modifications in subjects affected by long COVID-19, distinguishing between active and sedentary subjects. The data demonstrated the following: the perception of fatigue 1 year after the end of virus positivity was significantly reduced with respect to that observed after 6 months by more than 50% more in active subjects compared to sedentary ones; 6 months after the end of virus positivity, the force developed by active subjects was reduced (RM factor: p < 0.001, η2p = 0.527, post hoc: p < 0.001), but the reduction was more pronounced in sedentary ones (mean difference = 38.499 W); poor sleep quality and mild cognitive impairment were assessed in both active and sedentary subjects. In conclusion, the study suggests that the long COVID-19 fatigue was lower in active subjects respect to sedentary ones. A comparative analysis performed due to the overlap of functional alterations between long COVID-19 and ME/CFS showed that in a small percentage of the enrolled subjects (8%), the symptomatology reflected that of ME/CFS and was independent of the individual physical capacities.
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Bone healing is a major clinical issue, especially in bone defects of critical dimensions. Some studies have reported in vivo positive effects on bone healing by some bioactive compounds, such as the phenolic derivatives found in vegetables and plants, such as resveratrol, curcumin, and apigenin. The aim of this work was (1) to analyze in vitro in human dental pulp stem cells the effects of these three natural compounds on the gene expression of related genes downstream to RUNX2 and SMAD5, key factor transcriptions associated with osteoblast differentiation, in order to better understand the positive effects that can occur in vivo in bone healing, and (2) to evaluate in vivo the effects on bone healing of critical-size defects in the calvaria in rats of these three nutraceuticals tested in parallel and for the first time administered by the gastric route. Upregulation of the RUNX2, SMAD5, COLL1, COLL4, and COLL5 genes in the presence of apigenin, curcumin, and resveratrol was detected. In vivo, apigenin induced more consistent significant bone healing in critical-size defects in rat calvaria compared to the other study groups. The study findings encourage a possible therapeutic supplementation with nutraceuticals during the bone regeneration process.
Assuntos
Curcumina , Ratos , Humanos , Animais , Resveratrol , Curcumina/farmacologia , Apigenina , Subunidade alfa 1 de Fator de Ligação ao Core/genética , Osteogênese , Suplementos Nutricionais , Adjuvantes ImunológicosRESUMO
Previous studies have reported an association between oral microbial dysbiosis and the development and progression of pathologies in the central nervous system. Porphyromonas gingivalis (Pg), the keystone pathogen of the oral cavity, can induce a systemic antibody response measured in patients' sera using enzyme-linked immunosorbent assays. The present case-control study quantified the immune system's response to Pg abundance in the oral cavities of patients affected by different central nervous system pathologies. The study cohort included 87 participants: 23 healthy controls (HC), 17 patients with an acute neurological condition (N-AC), 19 patients with a chronic neurological condition (N-CH), and 28 patients with neurodegenerative disease (N-DEG). The results showed that the Pg abundance in the oral cavity was higher in the N-DEG patients than in the HC (p = 0.0001) and N-AC patients (p = 0.01). In addition, the Pg abundance was higher in the N-CH patients than the HCs (p = 0.005). Only the N-CH patients had more serum anti-Pg antibodies than the HC (p = 0.012). The inadequate response of the immune system of the N-DEG group in producing anti-Pg antibodies was also clearly indicated by an analysis of the ratio between the anti-Pg antibodies quantity and the Pg abundance. Indeed, this ratio was significantly lower between the N-DEG group than all other groups (p = 0.0001, p = 0.002, and p = 0.03 for HC, N-AC, and N-CH, respectively). The immune system's response to Pg abundance in the oral cavity showed a stepwise model: the response diminished progressively from the patients affected with an acute condition to the patients suffering from chronic nervous system disorders and finally to the patients affected by neurodegenerative diseases.
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Several purine receptors have been localised on skeletal muscle membranes. Previous data support the hypothesis that extracellular guanosine 5'-triphosphate (GTP) is an important regulatory factor in the development and function of muscle tissue. We have previously described specific extracellular binding sites for GTP on the plasma membrane of mouse skeletal muscle (C2C12) cells. Extracellular GTP induces an increase in intracellular Ca(2+) concentrations that results in membrane hyperpolarisation through Ca(2+)-activated K(+) channels, as has been demonstrated by patch-clamp experiments. This GTP-evoked increase in intracellular Ca(2+) is due to release of Ca(2+) from intracellular inositol-1,4,5-trisphosphate-sensitive stores. This enhances the expression of the myosin heavy chain in these C2C12 myoblasts and commits them to fuse into multinucleated myotubes, probably via a phosphoinositide-3-kinase-dependent signal-transduction mechanism. To define the signalling of extracellular GTP as an enhancer or modulator of myogenesis, we investigated whether the gene-expression profile of differentiated C2C12 cells (4 and 24 h in culture) is affected by extracellular GTP. To investigate the nuclear activity and target genes modulated by GTP, transcriptional profile analysis and real-time PCR were used. We demonstrate that in the early stages of differentiation, GTP up-regulates genes involved in different pathways associated with myogenic processes, including cytoskeleton structure, the respiratory chain, myogenesis, chromatin reorganisation, cell adhesion, and the Jak/Stat pathway, and down-regulates the mitogen-activated protein kinase pathway. GTP also increases the expression of three genes involved in myogenesis, Pp3ca, Gsk3b, and Pax7. Our data suggests that in the myogenic C2C12 cell line, extracellular GTP acts as a differentiative factor in the induction and sustaining of myogenesis.
Assuntos
Diferenciação Celular/genética , Guanosina Trifosfato/genética , Guanosina Trifosfato/farmacologia , Músculo Esquelético/fisiologia , Mioblastos/fisiologia , Transcrição Gênica/fisiologia , Animais , Linhagem Celular , Camundongos , Músculo Esquelético/efeitos dos fármacos , Mioblastos/efeitos dos fármacos , Transcrição Gênica/efeitos dos fármacosRESUMO
Bone blocks are proposed in oral bone regeneration for their biocompatibility and osteoconductivity. Human dental pulp stem cells (hDPSCs) have been used with bone substitutes as a biocomplex. Melatonin, produced by the pineal gland, has specific functions in the oral cavity in bone remodeling and enhancing the dual actions on osteoblasts and osteoclasts, the genic expression of bone markers. This study evaluated the osteogenic differentiation of hDPSCs, stimulated by melatonin on equine bone blocks. hDPSCs were cultured in growth medium (GM) or differentiation medium (DM) with or without the presence of equine bone blocks and 100 µm melatonin. After 7, 14, and 21 days of culture, expression of miRNAs (miR-133a, miR-133b, miR-135a, miR-29b, miR-206, and miR- let-7b) and genes (RUNX2, SMAD5, HDAC4, COL4a2, and COL5a3), osteocalcin levels and histolgic analyses were evaluated. Melatonin and equine blocks increased the osteogenic potential of hDPSCs even in GM, regulated miRNA and gene expression related to osteogenesis, and increased osteocalcin. hDPSCs cultured in DM showed a significantly higher osteogenic potential compared to GM. This study suggests that equine bone blocks and melatonin enhanced osteogenesis, stimulating early stages of cell differentiation. hDPSCs/equine bone block and melatonin represent a promising, useful biocomplex in bone regeneration with a potential for a possible clinical application.
Assuntos
Substitutos Ósseos , Melatonina , MicroRNAs , Animais , Diferenciação Celular , Células Cultivadas , Polpa Dentária , Cavalos , Humanos , Melatonina/farmacologia , Osteogênese , Células-TroncoRESUMO
[This corrects the article DOI: 10.1155/2018/2615372.].
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Recent studies support the hypothesis that microbes can seed some Alzheimer's disease (AD) cases, leading to inflammation and overproduction of amyloid peptides. Porphyromonas gingivalis (Pg) is a keystone pathogen of chronic periodontitis and has been identified as risk factor for the development and progression of AD. The present preliminary study aimed to quantify Pg abundance in neurodegenerative disease (ND) patients compared with neurologic patients without neurodegenerative disorders (no-ND) and healthy controls (HC) to determine possible association between Pg abundance and neurodegenerative process. Pg was quantified on DNA extracted from the oral samples of 49 patients and 29 HC by quantitative polymerase chain reaction (qPCR). Anti-Pg antibodies were also detected on patient serum samples by enzyme-linked immunosorbent assays (ELISA). The Pg abundance in the oral cavity was significantly different among groups (p = 0.004). It was higher in ND than no-ND (p = 0.010) and HC (p = 0.008). The Pg abundance was correlated with the antibodies (p = 0.001) with different slopes between ND and no-ND (p = 0.037). Pg abundance was not correlated with oral indices and comorbidities. These results extend our understanding of the association between oral pathogens and AD to other neurodegenerative processes, confirming the hypothesis that oral pathogens can induce an antibody systemic response, influencing the progression of the disease.
Assuntos
Anticorpos Antibacterianos/sangue , Boca/microbiologia , Doenças Neurodegenerativas/sangue , Doenças Neurodegenerativas/microbiologia , Porphyromonas gingivalis/metabolismo , Idoso , Idoso de 80 Anos ou mais , Infecções por Bacteroidaceae/sangue , Infecções por Bacteroidaceae/diagnóstico , Biomarcadores/sangue , Estudos de Coortes , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Doenças Neurodegenerativas/diagnóstico , Projetos Piloto , Porphyromonas gingivalis/isolamento & purificaçãoRESUMO
Skeletal muscle aging is a multifactorial process strictly related to progressive weakness. One of the results that were focused on was the fiber phenotype modification and their loss. The physiological muscle recruitment to contraction, basically prosecuted under volitional control, can also be engaged by means of Neuromuscular Electrical Stimulation (NMES). Knowing that the NMES is effective in improving muscle strength in active healthy elderly, the aim was to investigate which physiological modifications were able to produce in the Vastus lateralis muscle and the pathways involved. It was found that NMES increased the cross sectional area and the isometric strength of type II myofibers together with the activated myogenic pathway in order to shift glycolytic toward the oxidative phenotype II myofibers, at a molecular level and with an increase of maximal voluntary contraction (MVC) at a functional level. Using the TaqMan low density array on 48 different genes, we found that NMES specific gene regulation highlighted: (i) increased protein synthesis with respect to protein degradation; (ii) the activation of an apoptotic pathway involved in the differentiation process; (iii) increased regeneration signals; (iv) oxidative enzyme regulation. These pathways were validated via confirmatory RT-PCR for genes involved in the regeneration process as well as Myosin isoforms. We also investigated the oxidative stress status analyzing superoxide anion levels, the protein expression of two different superoxide dismutase and the activity of both catalase and superoxide anion dismutase, being two main antioxidant enzymes. In conclusion, data demonstrates that NMES is effective in producing physiological adaptation on Vastus Lateralis of active healthy elderly as well as providing new insights for further research on elderly who experienced muscle detriment for periodic or permanent immobility.
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Several studies suggest that extremely low-frequency magnetic fields (ELF-MFs) may enhance the free radical endogenous production. It is also well known that one of the unavoidable consequences of ageing is an overall oxidative stress-based decline in several physiological functions and in the general resistance to stressors. On the basis of these assumptions, the aim of this study was to establish whether the ageing process can increase susceptibility towards widely present ELF-MF-mediated pro-oxidative challenges. To this end, female Sprague-Dawley rats were continuously exposed to a sinusoidal 50 Hz, 0.1 mT magnetic field for 10 days. Treatment-induced changes in the major antioxidant protection systems and in the neurotrophic support were investigated, as a function of the age of the subjects. All analyses were performed in brain cortices, due to the high susceptibility of neuronal cells to oxidative injury. Our results indicated that ELF-MF exposure significantly affects anti-oxidative capability, both in young and aged animals, although in opposite ways. Indeed, exposed young individuals enhanced their neurotrophic signalling and anti-oxidative enzymatic defence against a possible ELF-MF-mediated increase in oxygen radical species. In contrast, aged subjects were not capable of increasing their defences in response to ELF-MF treatment but, on the contrary, they underwent a significant decrease in the major antioxidant enzymatic activities. In conclusion, our data seem to suggest that the exposure to ELF-MFs may act as a risk factor for the occurrence of oxidative stress-based nervous system pathologies associated with ageing.
Assuntos
Envelhecimento/fisiologia , Antioxidantes/metabolismo , Encéfalo/metabolismo , Encéfalo/efeitos da radiação , Campos Eletromagnéticos/efeitos adversos , Animais , Encéfalo/citologia , Encéfalo/enzimologia , Catalase/metabolismo , Feminino , Glutationa Peroxidase/metabolismo , Glutationa Redutase/metabolismo , Glutationa Transferase/metabolismo , Estresse Oxidativo/efeitos da radiação , Ratos , Ratos Sprague-Dawley , Superóxido Dismutase/metabolismo , Fatores de TempoRESUMO
The excitation-contraction coupling in skeletal muscle is modulated by nitric oxide via redox status modification of ryanodine receptor on sarcoplasmic reticulum during events that lead to muscle contraction. We have synthesized a derivative of antilipidemic drug, gemfibrozil, in which a NO-donor furoxan moiety is joined to the fibrate by an ester linkage. Aim of the present study was to determine if the NO released from the above compound is capable of influencing the NO-sensible E-C coupling steps in skeletal muscle and if this effect could be potentially utilised for physiopathological studies and pharmaceutical applications. To obtain this goal we decided to study some of the excitation-contraction mechanisms in the presence of NO-releasing derivative of gemfibrozil in skeletal muscle C2C12 cell line.
Assuntos
Ésteres/farmacologia , Genfibrozila/análogos & derivados , Genfibrozila/farmacologia , Contração Muscular/efeitos dos fármacos , Fibras Musculares Esqueléticas/efeitos dos fármacos , Músculo Esquelético/efeitos dos fármacos , Doadores de Óxido Nítrico/farmacologia , Oxidiazóis/farmacologia , Animais , Linhagem Celular , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Ésteres/síntese química , Ésteres/química , Genfibrozila/síntese química , Genfibrozila/química , Camundongos , Estrutura Molecular , Contração Muscular/fisiologia , Fibras Musculares Esqueléticas/citologia , Fibras Musculares Esqueléticas/fisiologia , Músculo Esquelético/citologia , Músculo Esquelético/fisiologia , Óxido Nítrico/metabolismo , Doadores de Óxido Nítrico/síntese química , Doadores de Óxido Nítrico/química , Oxidiazóis/síntese química , Oxidiazóis/químicaRESUMO
BACKGROUND: Denervation triggers numerous molecular responses in skeletal muscle, including the activation of catabolic pathways and oxidative stress, leading to progressive muscle atrophy. Histone deacetylase 4 (HDAC4) mediates skeletal muscle response to denervation, suggesting the use of HDAC inhibitors as a therapeutic approach to neurogenic muscle atrophy. However, the effects of HDAC4 inhibition in skeletal muscle in response to long-term denervation have not been described yet. METHODS: To further study HDAC4 functions in response to denervation, we analyzed mutant mice in which HDAC4 is specifically deleted in skeletal muscle. RESULTS: After an initial phase of resistance to neurogenic muscle atrophy, skeletal muscle with a deletion of HDAC4 lost structural integrity after 4 weeks of denervation. Deletion of HDAC4 impaired the activation of the ubiquitin-proteasome system, delayed the autophagic response, and dampened the OS response in skeletal muscle. Inhibition of the ubiquitin-proteasome system or the autophagic response, if on the one hand, conferred resistance to neurogenic muscle atrophy; on the other hand, induced loss of muscle integrity and inflammation in mice lacking HDAC4 in skeletal muscle. Moreover, treatment with the antioxidant drug Trolox prevented loss of muscle integrity and inflammation in in mice lacking HDAC4 in skeletal muscle, despite the resistance to neurogenic muscle atrophy. CONCLUSIONS: These results reveal new functions of HDAC4 in mediating skeletal muscle response to denervation and lead us to propose the combined use of HDAC inhibitors and antioxidant drugs to treat neurogenic muscle atrophy.
Assuntos
Histona Desacetilases/fisiologia , Proteínas Musculares/fisiologia , Músculo Esquelético/inervação , Atrofia Muscular/patologia , Animais , Antioxidantes/farmacologia , Antioxidantes/uso terapêutico , Autofagia/fisiologia , Cromanos/farmacologia , Cromanos/uso terapêutico , Feminino , Histona Desacetilases/deficiência , Histona Desacetilases/genética , Camundongos Knockout , Denervação Muscular/métodos , Proteínas Musculares/deficiência , Proteínas Musculares/genética , Músculo Esquelético/efeitos dos fármacos , Músculo Esquelético/metabolismo , Músculo Esquelético/patologia , Atrofia Muscular/genética , Atrofia Muscular/metabolismo , Atrofia Muscular/prevenção & controle , Estresse Oxidativo/efeitos dos fármacos , Estresse Oxidativo/fisiologia , Complexo de Endopeptidases do Proteassoma/metabolismo , Ubiquitina/metabolismoRESUMO
Sarcopenia is the age-related loss of skeletal muscle mass, strength, and function. It is associated with regenerative difficulties by satellite cells, adult muscle stem cells, and alteration of oxidative management, mainly the increase in superoxide anions (O2â¢-). We aimed to investigate the relation between regenerative deficit in elderly and increase in O2â¢- production along with mitochondrial alterations. Myoblasts and myotubes from skeletal muscle of young and elderly healthy subjects (27.8 ± 6 and 72.4 ± 6.5 years old) were measured: (1) superoxide dismutase activity and protein content, (2) mitochondrial O2â¢- production levels, (3) O2â¢- production variability, and (4) mitochondrial bioenergetic profile. Compared to young myoblasts, elderly myoblasts displayed decreased SOD2 protein expression, elevated mitochondrial O2â¢- baseline levels, and decreased oxidative phosphorylation and glycolysis. Additionally, elderly versus young myotubes showed elevated mitochondrial O2â¢- levels when stressed with N-acetyl cysteine or high glucose and higher glycolysis despite showing comparable oxidative phosphorylation levels. Altogether, the elderly may have less metabolic plasticity due to the impaired mitochondrial function caused by O2â¢-. However, the increased energy demand related to the differentiation process appears to activate compensatory mechanisms for the partial mitochondrial dysfunction.
Assuntos
Biópsia/métodos , Fibras Musculares Esqueléticas/metabolismo , Músculo Esquelético/metabolismo , Mioblastos/metabolismo , Superóxidos/metabolismo , Adulto , Idoso , Diferenciação Celular , Células Cultivadas , Feminino , Humanos , Masculino , Mioblastos/patologiaRESUMO
The surface roughness of dental implants influences the proliferation and differentiation rate of adult mesenchymal stem cells (MSCs). The aim of the present study was to evaluate whether specifically treated titanium implant surfaces influenced human dental pulp stem cells (DPSCs) differentiation in an osteogenic pattern through modulation of microRNAs expression. The degree of differentiation was evaluated after 7, 14, and 21 days, through the expression of microRNAs characterizing the osteogenesis (miR-133 and miR-135), of Runx2 and Smad5 (key factor transcriptions associated with osteoblast differentiation) and Osteocalcin, marker for the bone formation process. DPSCs were cultured on sandblasted and acid-etched titanium disks, with (Test) or without the presence of ions (Control). Early differentiation of DPSCs cultured on titanium could be detected at all the evaluated time points, respect to cells grown alone. Moreover, the Test surfaces seemed to induce a more marked cells differentiation. The obtained results demonstrated that microRNAs played a pivotal role in the differentiation of MSCs and could be used as marker of osteogenic differentiation. Furthermore, the evaluated ionized sandblasted and acid-etched surface seemed to markedly enhance the development of osteoblast cells. A faster osseointegration could be achieved in the presence of specifically treated implant surfaces, promising encouraging clinical outcomes. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 953-965, 2017.
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Implantes Dentários , Polpa Dentária/metabolismo , Regulação da Expressão Gênica , Teste de Materiais , MicroRNAs/biossíntese , Células-Tronco/metabolismo , Titânio/química , Diferenciação Celular , Células Cultivadas , Polpa Dentária/citologia , Humanos , Células-Tronco/citologia , Propriedades de SuperfícieRESUMO
Physical activity has been demonstrated to be effective in the prevention and treatment of different chronic conditions, including type 2 diabetes (T2D). In particular, several studies highlighted how the beneficial effects of physical activity may be related to the stability of the DNA molecule, such as longer telomeric ends. Here we analyze the effect of exercise training on telomere length, spontaneous and H2O2-induced DNA damage, as well as the apoptosis level in leukocytes from untrained or trained T2D patients vs. age-matched control subjects (CS) (57-66 years). Moreover, expression analysis of selected genes belonging to DNA repair systems, cell cycle control, antioxidant and defence systems was performed. Subjects that participated in a regular exercise program showed a longer telomere sequence than untrained counterparts. Moreover, ex vivo treatment of leukocytes with H2O2 highlighted that: (1) oxidative DNA damage induced similar telomere attrition in all groups; (2) in T2D subjects, physical activity seemed to prevent a significant increase of genomic oxidative DNA damage induced by chronic exposure to pro-oxidant stimulus, and (3) decreased the sensitivity of leukocytes to apoptosis. Finally, the gene expression analysis in T2D subjects suggested an adaptive response to prolonged exercise training that improved the response of specific genes.
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Diabetes Mellitus Tipo 2/genética , Diabetes Mellitus Tipo 2/metabolismo , Exercício Físico , Instabilidade Genômica , Idoso , Apoptose/efeitos dos fármacos , Apoptose/genética , Estudos de Casos e Controles , Dano ao DNA , Perfilação da Expressão Gênica , Humanos , Peróxido de Hidrogênio/metabolismo , Peróxido de Hidrogênio/farmacologia , Hibridização in Situ Fluorescente , Leucócitos/metabolismo , Masculino , Pessoa de Meia-Idade , Telômero/genética , Homeostase do Telômero , Encurtamento do Telômero/efeitos dos fármacos , Encurtamento do Telômero/genéticaRESUMO
The aim of this study was to determine whether neuromuscular electrical stimulation (NMES) affects skeletal muscle regeneration through a reduction of oxidative status in satellite cells of healthy elderly subjects. Satellite cells from the vastus lateralis skeletal muscle of 12 healthy elderly subjects before and after 8 wk of NMES were allowed to proliferate to provide myogenic populations of adult stem cells [myogenic precursor cells (MPCs)]. These MPCs were then investigated in terms of their proliferation, their basal cytoplasmic free Ca2+ concentrations, and their expression of myogenic regulatory factors (PAX3, PAX7, MYF5, MYOD, and MYOG) and micro-RNAs (miR-1, miR-133a/b, and miR-206). The oxidative status of these MPCs was evaluated through superoxide anion production and superoxide dismutase and glutathione peroxidase activities. On dissected single skeletal myofibers, the nuclei were counted to determine the myonuclear density, the fiber phenotype, cross-sectional area, and tension developed. The MPCs obtained after NMES showed increased proliferation rates along with increased cytoplasmic free Ca2+ concentrations and gene expression of MYOD and MYOG on MPCs. Muscle-specific miR-1, miR-133a/b, and miR-206 were upregulated. This NMES significantly reduced superoxide anion production, along with a trend to reduction of superoxide dismutase activity. The NMES-dependent stimulation of muscle regeneration enhanced satellite cell fusion with mature skeletal fibers. NMES improved the regenerative capacity of skeletal muscle in elderly subjects. Accordingly, the skeletal muscle strength and mobility of NMES-stimulated elderly subjects significantly improved. NMES may thus be further considered for clinical or ageing populations.NEW & NOTEWORTHY The neuromuscular electrical stimulation (NMES) effect on skeletal muscle regeneration was assessed in healthy elderly subjects for the first time. NMES improved the regenerative capacity of skeletal muscle through increased myogenic precursor cell proliferation and fusion with mature myofibers. The increased cytoplasmic free Ca2+ concentration along with MYOD, MYOG, and micro-RNA upregulation could be related to reduced O2·- production, which, in turn, favors myogenic regeneration. Accordingly, the skeletal muscle strength of NMES-stimulated lower limbs of healthy elderly subjects improved along with their mobility.