Interrelated but Not Time-Aligned Response in Myogenic Regulatory Factors Demethylation and mRNA Expression after Divergent Exercise Bouts.

INTRODUCTION: DNA methylation regulates exercise-induced changes in the skeletal muscle transcriptome. However, the specificity and the time course responses in the myogenic regulatory factors DNA methylation and mRNA expression after divergent exercise modes are unknown. PURPOSE: This study aimed to compare the time course changes in DNA methylation and mRNA expression for selected myogenic regulatory factors ( MYOD1 , MYF5 , and MYF6 ) immediately after, 4 h after, and 8 h after a single bout of resistance exercise (RE), high-intensity interval exercise (HIIE), and concurrent exercise (CE). METHODS: Nine healthy but untrained males (age, 23.9 ± 2.8 yr; body mass, 70.1 ± 14.9 kg; peak oxygen uptake [V̇O 2peak ], 41.4 ± 5.2 mL·kg -1 ·min -1 ; mean ± SD) performed a counterbalanced, randomized order of RE (4 × 8-12 repetition maximum), HIIE (12 × 1 min sprints at V̇O 2peak running velocity), and CE (RE followed by HIIE). Skeletal muscle biopsies (vastus lateralis) were taken before (REST) immediately (0 h), 4 h, and 8 h after each exercise bout. RESULTS: Compared with REST, MYOD1 , MYF5 , and MYF6 , mean methylation across all CpGs analyzed was reduced after 4 and 8 h in response to all exercise protocols ( P < 0.05). Reduced levels of MYOD1 methylation were observed after HIIE and CE compared with RE ( P < 0.05). Compared with REST, all exercise bouts increased mRNA expression over time ( MYOD1 at 4 and 8 h, and MYF6 at 4 h; P < 0.05). MYF5 mRNA expression was lower after 4 h compared with 0 h and higher at 8 h compared with 4 h ( P < 0.05). CONCLUSIONS: We observed an interrelated but not time-aligned response between the exercise-induced changes in myogenic regulatory factors demethylation and mRNA expression after divergent exercise modes. Despite divergent contractile stimuli, changes in DNA methylation and mRNA expression in skeletal muscle were largely confined to the late (4-8 h) recovery period and similar between the different exercise challenges.

Exercise-Induced Circulating microRNAs: Potential Key Factors in the Control of Breast Cancer.

Losses in skeletal muscle mass, strength, and metabolic function are harmful in the pathophysiology of serious diseases, including breast cancer. Physical exercise training is an effective non-pharmacological strategy to improve health and quality of life in patients with breast cancer, mainly through positive effects on skeletal muscle mass, strength, and metabolic function. Emerging evidence has also highlighted the potential of exercise-induced crosstalk between skeletal muscle and cancer cells as one of the mechanisms controlling breast cancer progression. This intercellular communication seems to be mediated by a group of skeletal muscle molecules released in the bloodstream known as myokines. Among the myokines, exercise-induced circulating microRNAs (c-miRNAs) are deemed to mediate the antitumoral effects produced by exercise training through the control of key cellular processes, such as proliferation, metabolism, and signal transduction. However, there are still many open questions regarding the molecular basis of the exercise-induced effects on c-miRNA on human breast cancer cells. Here, we present evidence regarding the effect of exercise training on c-miRNA expression in breast cancer, along with the current gaps in the literature and future perspectives.

Time Course of Skeletal Muscle miRNA Expression after Resistance, High-Intensity Interval, and Concurrent Exercise.

INTRODUCTION: Exercise-induced microRNA (miRNA) expression has been implicated in the regulation of skeletal muscle plasticity. However, the specificity and acute time course in miRNA expression after divergent exercise modes are unknown. In a randomized crossover design, we compared the acute expression profile of eight skeletal muscle miRNAs previously reported to be involved in skeletal muscle development, growth, and maintenance after a bout of either resistance exercise (RE), high-intensity interval exercise (HIIE), and concurrent resistance and high-intensity interval exercises (CE). METHODS: Nine untrained young men (23.9 ± 2.8 yr, 70.1 ± 14.9 kg, 177.2 ± 3.0 cm, 41.4 ± 5.2 mL·kg-1·min-1) underwent a counterbalanced crossover design in which they performed bouts of RE (2 × 10 repetitions maximum 45° leg press and leg extension exercises), HIEE (12 × 1-min sprints at V˙O2peak with 1-min rest intervals between sprints), and CE (RE followed by HIIE), separated by 1 wk. Vastus lateralis biopsies were harvested immediately before (Pre) and immediately (0 h), 4 h, and 8 h after each exercise bout. RESULTS: There were similar increases (main effect of time; P < 0.05) in miR-1-3p, miR-133a-3p, miR-133b, miR-181a-3p, and miR-486 expression at 8 h from Pre with all exercise modes. Besides a main effect of time, miR-23a-3p and miR-206 presented a main effect of condition with lower expression after HIIE compared with RE and CE. CONCLUSIONS: Select miRNAs (miR-1-3p, miR-133a-3p, miR-133b, miR-23a-3p, miR-181a-3p, miR-206, miR-486) do not exhibit an expression specificity in the acute recovery period after a single bout of RE, HIIE, or CE in skeletal muscle. Our data also indicate that RE has a higher effect on the expression of miR-23a-3p and miR-206 than HIIE. As upregulation of these miRNAs seems to be confined to the 8-h period after exercise, this may subsequently affect the expression patterns of target mRNAs forming the basis of exercise-induced adaptive responses.

Stress and Physical Inactivity: Two Explosive Ingredients for the Heart in COVID-19 Pandemic Times.

BACKGROUND: Coronavirus disease 2019 (Covid-19) pandemic is a global health crisis that has culminated in thousands of deaths. In order to reduce the spread of the Sars-CoV-2 virus, governments of several countries have adopted social isolation as a strategy. However, social isolation has culminated in deleterious effects on the population's health, including increased physical inactivity, stress and, consequently, adverse changes in body composition, cardiorespiratory capacity, muscle strength, physical functionality, and vascular events, which are increasingly pointed out as the main determinants of cardiovascular health. Staying physically active during lockdown is a challenge, especially for the population with a higher risk of mortality from COVID-19, who are still encouraged to maintain social distance until there is a vaccine available. Strategies to avoid physical inactivity and reduce stress levels can promote cardiovascular protection and must be considered during COVID-19 time. OBJECTIVE: The aim of this paper is to discuss the risks of physical inactivity and stress for the cardiovascular system during the COVID-19 pandemic and propose strategies to protect cardiovascular health. CONCLUSION: A home-based training protocol could be an interesting and effective strategy for the population who need to remain physically active and safe at home.

Attenuated PGC-1α Isoforms following Endurance Exercise with Blood Flow Restriction.

INTRODUCTION: Exercise performed with blood flow restriction simultaneously enhances the acute responses to both myogenic and mitochondrial pathways with roles in training adaptation. We investigated isoform-specific gene expression of the peroxisome proliferator-activated receptor gamma coactivator 1 and selected target genes and proteins regulating skeletal muscle training adaptation. METHODS: Nine healthy, untrained males participated in a randomized, counterbalanced, crossover design in which each subject completed a bout of low-intensity endurance exercise performed with blood flow restriction (15 min cycling at 40% of V˙O2peak, BFR-EE), endurance exercise (30 min cycling at 70% of V˙O2peak, EE), or resistance exercise (4 × 10 repetitions of leg press at 70% of one-repetition maximum) separated by at least 1 wk of recovery. A single resting muscle biopsy (vastus lateralis) was obtained 2 wk before the first exercise trial (rest) and 3 h after each bout. RESULTS: Total PGC-1α mRNA abundance, along with all four isoforms, increased above rest with EE only (P < 0.05) being higher than BFR-EE (P < 0.05). PGC-1α1, 2, and 4 were higher after EE compared with resistance exercise (P < 0.05). EE also increased vascular endothelial growth factor, Hif-1α, and MuRF-1 mRNA abundance above rest (P < 0.05), whereas COXIV mRNA expression increased with EE compared with BFR-EE (P < 0.05). CONCLUSION: The attenuated expression of all four PGC-1α isoforms when EE is performed with blood flow restriction suggests this type of exercise provides an insufficient stimulus to activate the signaling pathways governing mitochondrial and angiogenesis responses observed with moderate- to high-intensity EE.

Sete semanas de treinamento melhoram a resistência aeróbia e a potência muscular de jogadores de futebol / Seven weeks of training improve the endurance and muscle power in soccer players

O futebol se caracteriza pela alternância de períodos de atividades de curta duração e alta intensidade intercalada por momentos de recuperação. Desta forma há uma exigência de desenvolvimento de diversas capacidades biomotoras ao longo de uma temporada. O objetivo desse estudo foi avaliar e discutir os efeitos de sete semanas de treinamento nas capacidades biomotoras. Participaram deste estudo 15 atletas profissionais de futebol com idade média de 25,3±3,8 anos, massa corporal de 76,6±7,5 Kg, estatura de 1,77±0,1 m e percentual de gordura de 11,7% que disputaram o Campeonato da terceira divisão nacional. Os conteúdos de treinamento foram divididos em funcional e neuromuscular. Todos os atletas foram submetidos a dois testes máximos: Yo-Yo Edurance Test Nível 1 e salto horizontal em dois momentos distintos (M1): início do programa de treinamento e (M2) após o término do período preparatório. Os dados coletados foram armazenados em banco computacional, produzindo-se informações no plano descritivo (medidas de centralidade e dispersão) e, no inferencial, após assumir a normalidade dos dados pelo teste de Shapiro-Wilk, utilizou-se o teste t de Student para amostras pareadas, a fim de se verificar as mudanças ocorridas nas capacidades entre os momentos avaliados. O principal resultado, quanto ao indicador funcional, apresentou melhora na distância percorrida no Yo-Yo Endurance Test Nível 1 de M1 (2376,0±202,4 m) para M2 (2581,3±173,1 m). O indicador neuromuscular apontou melhora no salto horizontal de M1 (2,44±0,1 m) para M2 (2,48±0,1 m). Assim, concluímos com os resultados encontrados que a metodologia utilizada no presente estudo foi considerada eficaz em causar alteração sobre o indicador funcional, bem como no neuromuscular durante o período estudado.

Soccer is characterized by alternating periods of activities of short duration and high intensity interspersed with moments of recovery. Thus there is a demand of development of various physical capacities. The aim of this study was to evaluate and discuss the effects of seven weeks of training on the physical capacities. 15 professionals soccer players with an average age of 25, 3±3,8, weigth of 76,6±7,5, height of 1,77±0,1 m and body fat of 11,7% were included in this study and who dispute the third division of national championship. The training program was divided into functional and neuromuscular. All the athletes were submitted to maximal tests: Yo-Yo Edurance Test Level 1 andStanding long jump test which were performed before the training program (M1) and after seven weeks (M2). The data collected were kept in a computer, producing the information in the plan descriptive (measures of centrality and dispersion) and, inferentially, after taking the data for normality by the Shapiro-Wilk, we used the Student t-test for paired samples, in order to verify the possible changes in the capacities between the both moments. The main results, as the functional indicator, showed improvement on the cover distance in the Yo-Yo Endurance Test Level 1 from M1 (2376,0±202,4 m) to M2 (2581,3±173,1 m). The neuromuscular indicator showed improvement in the Standing long jump test from M1 (2,44±0,1 m) to M2 (2,48±0,1 m). Thus, we conclude with the results found that the methodology used in this study was effective in causing change on the functional indicator, as well as in the neuromuscular indicator during the study period.