Exercise Training Enhances Myocardial Mitophagy and Improves Cardiac Function via Irisin/FNDC5-PINK1/Parkin Pathway in MI Mice

Exerkine-mediated organ interactions: A new interpretation of exercise on cardiovascular function improvement

Cardiovascular diseases impair the structure and function of distal organs, including the liver, skeletal muscle, kidney, and adipose tissue. Exercise stimulates the interaction between the cardiovascular system and distal organs that is important for disease rehabilitation and organ health. However, the mechanisms by which exercise improves cardiovascular function through exerkine-mediated organ crosstalk remain incompletely elucidated. We used cardiovascular, exercise, exerkines, skeletal muscle, liver, kidney, and adipose tissue as keywords to search for the relevant articles, sorted out the differences between different exercise types, summarized the functions of 17 exerkines, focused on reviewing and categorizing the molecular mechanisms of interactions between the cardiovascular system and remote organs. We also look forward to future research perspectives on exercise prevention and control of chronic metabolic diseases. The aim of this review is to provide a new theoretical basis for establishing clinical rehabilitation and exercise prescriptions for cardiovascular system diseases.

Exercise enhances cardiomyocyte mitochondrial homeostasis to alleviate left ventricular dysfunction in pressure overload induced remodelling

This study aims to explore how exercise enhances mitochondrial regulation and mitigates pathological cardiac hypertrophy. Rat groups were assigned as the control group (CN, n = 8), sham group (sham, n = 8), model group (SC, n = 16) and exercise group (SE, n = 20). A bioinformatics analysis was conducted to uncover the underlying mechanisms.H9C2 cells were divided into: the Ang II 0 h group (CON), Ang II 48 h group (Ang II), Ang II 48 h + sh-control group (sh-GFP + Ang II), Ang II 48 h + sh-ndufb10 group (sh-ndufb10 + Ang II), Ang II 48 h + overexpressedndufb10 control group (Ad-GFP + Ang II) and Ang II 48 h + over-expressedndufb10group (Ad-ndufb10 + Ang II). Mitochondrial function was measured. mRNA and protein expression were assessed by qPCR or western blot analysis respectively. In the SC group, a significant increase was observed in cardiomyocyte diameter, cardiac function, autophagy, and apoptosis. After 8 weeks of swimming exercise, there was a substantial reduction in cardiomyocyte diameter, an improvement in cardiac function, a mitigation of mitochondrial fission and autophagy. Ndufb10 was markedly enriched in oxidative phosphorylation and downregulated in the SC group, while it was upregulated in the SE group. In the sh-ndufb10 group, mitochondrial fusion was suppressed; fission and autophagy were further facilitated; mitochondrial membrane potential, mPTP, and ROS levels increased; and TUNEL positive nuclei and apoptosis-related proteins showed significant upregulation. Overexpression of ndufb10 reversed pathological hypertrophy, mitochondrial autophagy, mitochondrial dysfunction, and cardiomyocyte apoptosis in vitro. Swimming exercise improves mitochondrial abnormalities and reduces cardiomyocyte hypertrophy through regulation of the ndufb10 in left ventricular hypertrophy.

The mechanisms of exercise improving cardiovascular function by stimulating Piezo1 and TRP ion channels: a systemic review

Mechanosensitive ion channels are widely distributed in the heart, lung, bladder and other tissues, and plays an important role in exercise-induced cardiovascular function promotion. By reviewing the PubMed databases, the results were summarized using the terms "Exercise/Sport", "Piezo1", "Transient receptor potential (TRP)" and "Cardiovascular" as the keywords, 124-related papers screened were sorted and reviewed. The results showed that: (1) Piezo1 and TRP channels play an important role in regulating blood pressure and the development of cardiovascular diseases such as atherosclerosis, myocardial infarction, and cardiac fibrosis; (2) Exercise promotes cardiac health, inhibits the development of pathological heart to heart failure, regulating the changes in the characterization of Piezo1 and TRP channels; (3) Piezo1 activates downstream signaling pathways with very broad pathways, such as AKT/eNOS, NF-κB, p38MAPK and HIPPO-YAP signaling pathways. Piezo1 and Irisin regulate nuclear localization of YAP and are hypothesized to act synergistically to regulate tissue mechanical properties of the cardiovascular system and (4) The cardioprotective effects of exercise through the TRP family are mostly accomplished through Ca2+ and involve many signaling pathways. TRP channels exert their important cardioprotective effects by reducing the TRPC3-Nox2 complex and mediating Irisin-induced Ca2+ influx through TRPV4. It is proposed that exercise stimulates the mechanosensitive cation channel Piezo1 and TRP channels, which exerts cardioprotective effects. The activation of Piezo1 and TRP channels and their downstream targets to exert cardioprotective function by exercise may provide a theoretical basis for the prevention of cardiovascular diseases and the rehabilitation of clinical patients.

Irisin in degenerative musculoskeletal diseases: Functions in system and potential in therapy

Degenerative musculoskeletal diseases are a class of diseases related to the gradual structural and functional deterioration of muscles, joints, and bones, including osteoarthritis (OA), osteoporosis (OP), sarcopenia (SP), and intervertebral disc degeneration (IDD). As the proportion of aging people around the world increases, degenerative musculoskeletal diseases not only have a multifaceted impact on patients, but also impose a huge burden on the medical industry in various countries. Therefore, it is crucial to find key regulatory factors and potential therapeutic targets. Recent studies have shown that irisin plays an important role in degenerative musculoskeletal diseases, suggesting that it may become a key molecule in the prevention and treatment of degenerative diseases of the musculoskeletal system. Therefore, this review provides a comprehensive description of the release and basic functions of irisin, and summarizes the role of irisin in OA, OP, SP, and IDD from a cellular and tissue perspective, providing comprehensive basis for clinical application. In addition, we summarized the many roles of irisin as a key information molecule in bone-muscle-adipose crosstalk and a regulatory molecule involved in inflammation, senescence, and cell death, and proposed the interesting possibility of irisin in degenerative musculoskeletal diseases.

Irisin's emerging role in Parkinson's disease research: A review from molecular mechanisms to therapeutic prospects

Parkinson's disease (PD), a neurodegenerative disorder characterized by impaired motor function, is typically treated with medications and surgery. However, recent studies have validated physical exercise as an effective adjunct therapy, significantly improving both motor and non-motor symptoms in PD patients. Irisin, a myokine, has garnered increasing attention for its beneficial effects on the nervous system. Research has shown that irisin plays a crucial role in regulating metabolic balance, optimizing autophagy, maintaining mitochondrial quality, alleviating oxidative stress and neuroinflammation, and regulating cell death-all processes intricately linked to the pathogenesis of PD. This review examines the mechanisms through which irisin may counteract PD, provides insights into its biological effects, and considers its potential as a target for therapeutic strategies.

High intensity interval training as a therapy: Mitophagy restoration in breast cancer

Recent studies have highlighted the role of mitophagy in tumorigenesis. This study aimed to investigate the effects of high-intensity interval training (HIIT) on mitophagy in tumor tissues of mice with breast cancer. Twenty-eight female BALB/c mice were randomly assigned to four groups: Healthy Control (CO), Cancer (CA), Exercise (EX), and Cancer + Exercise (CA + EX). Mammary tumors were induced in the CA and CA + EX groups via 4T1 cell injections. Upon confirmation of tumor formation, the EX and CA + EX groups underwent 8 weeks (40 sessions) of HIIT, comprising 4-10 intervals of running at 80-100 % of maximum speed. The expression levels of mitophagy-related proteins, including parkin, PTEN-induced putative kinase 1 (PINK1), NIP3-like protein X (NIX), BCL2 interacting protein-3 (BINP3), microtubule-associated protein light chain 3-I (LC3-I), microtubule-associated protein light chain 3-II (LC3-II), AMP-activated protein kinase (AMPK), Unc-51 like autophagy activating kinase-1 (ULK1), and sirtuin-1 (SIRT1), were measured in breast and tumor tissues. Tumor volume relative to body weight was assessed weekly during the eight-week HIIT intervention. Protein expression of parkin, PINK1, NIX, BINP3, LC3-II, LC3-I, AMPK, ULK1, and SIRT1 was reduced in the breast tissue of the CA group, while HIIT restored expression levels across all measured variables (P < 0.01). Additionally, tumor volume relative to body weight was significantly lower in the CA + EX group compared to the CA group from weeks 3-8 (P < 0.01). These findings suggest that breast cancer suppresses mitophagy, yet HIIT effectively reverses this suppression, potentially reducing tumor burden. HIIT may thus represent a promising therapeutic strategy for managing breast cancer.

The role and underlying mechanisms of irisin in exercise-mediated cardiovascular protection

Irisin, a product of the post-translational processing of fibronectin type III domain-containing protein 5 (FNDC5), is a novel myokine which is upregulated during exercise. This hormone not only promotes the transformation of white adipose tissue into a brown-fat-like phenotype but also enhances energy expenditure and mitigates fat accumulation. Its role is crucial in the management of certain metabolic disorders such as diabetes and heart disease. Of note, the type of exercise performed significantly affects blood irisin levels, indicating the critical role of physical activity in regulating this hormone. This article aims to summarize the current scientific understanding of the role of irisin and the mechanisms through which it mediates cardiovascular protection through exercise. Moreover, this article aims to establish irisin as a potential target for preventing and treating cardiovascular diseases.

Myokines May Be the Answer to the Beneficial Immunomodulation of Tailored Exercise-A Narrative Review

Exercise can regulate the immune function, activate the activity of immune cells, and promote the health of the organism, but the mechanism is not clear. Skeletal muscle is a secretory organ that secretes bioactive substances known as myokines. Exercise promotes skeletal muscle contraction and the expression of myokines including irisin, IL-6, BDNF, etc. Here, we review nine myokines that are regulated by exercise. These myokines have been shown to be associated with immune responses and to regulate the proliferation, differentiation, and maturation of immune cells and enhance their function, thereby serving to improve the health of the organism. The aim of this article is to review the effects of myokines on intrinsic and adaptive immunity and the important role that exercise plays in them. It provides a theoretical basis for exercise to promote health and provides a potential mechanism for the correlation between muscle factor expression and immunity, as well as the involvement of exercise in body immunity. It also provides the possibility to find a suitable exercise training program for immune system diseases.

Irisin Protects Musculoskeletal Homeostasis via a Mitochondrial Quality Control Mechanism

Irisin, a myokine derived from fibronectin type III domain-containing 5 (FNDC5), is increasingly recognized for its protective role in musculoskeletal health through the modulation of mitochondrial quality control. This review synthesizes the current understanding of irisin's impact on mitochondrial biogenesis, dynamics, and autophagy in skeletal muscle, elucidating its capacity to bolster muscle strength, endurance, and resilience against oxidative-stress-induced muscle atrophy. The multifunctional nature of irisin extends to bone metabolism, where it promotes osteoblast proliferation and differentiation, offering a potential intervention for osteoporosis and other musculoskeletal disorders. Mitochondrial quality control is vital for cellular metabolism, particularly in energy-demanding tissues. Irisin's influence on this process is highlighted, suggesting its integral role in maintaining cellular homeostasis. The review also touches upon the regulatory mechanisms of irisin secretion, predominantly induced by exercise, and its systemic effects as an endocrine factor. While the therapeutic potential of irisin is promising, the need for standardized measurement techniques and further elucidation of its mechanisms in humans is acknowledged. The collective findings underscore the burgeoning interest in irisin as a keystone in musculoskeletal health and a candidate for future therapeutic strategies.

The role of mitophagy in metabolic diseases and its exercise intervention

Mitochondria are energy factories that sustain life activities in the body, and their dysfunction can cause various metabolic diseases that threaten human health. Mitophagy, an essential intracellular mitochondrial quality control mechanism, can maintain cellular and metabolic homeostasis by removing damaged mitochondria and participating in developing metabolic diseases. Research has confirmed that exercise can regulate mitophagy levels, thereby exerting protective metabolic effects in metabolic diseases. This article reviews the role of mitophagy in metabolic diseases, the effects of exercise on mitophagy, and the potential mechanisms of exercise-regulated mitophagy intervention in metabolic diseases, providing new insights for future basic and clinical research on exercise interventions to prevent and treat metabolic diseases.

Cardioprotective Effects of Exercise: The Role of Irisin and Exosome

Exercise is an effective measure for preventing and treating cardiovascular diseases, although the exact molecular mechanism remains unknown. Previous studies have shown that both irisin and exosomes can improve the course of cardiovascular disease independently. Therefore, it is speculated that the cardiovascular protective effect of exercise is also related to its ability to regulate the concentrations of irisin and exosomes in the circulatory system. In this review, the potential synergistic interactions between irisin and exosomes are examined, as well as the underlying mechanisms including the AMPK/PI3K/AKT pathway, the TGFβ1/Smad2/3 pathway, the PI3K/AKT/VEGF pathway, and the PTEN/PINK1/Parkin pathway are examined. This paper provides evidence to propose that exercise promotes the release of exosomes enriched with irisin, miR-486-5p and miR-342-5p from skeletal muscles, which results in the activation protective networks in the cardiovascular system. Moreover, the potential synergistic effect in exosomal cargo can provide new ideas for clinical research of exercise mimics.

Irisin inhibits CCK-8-induced TNF-α production via integrin αVβ5-NF-κB signaling pathways in Nile tilapia (Oreochromis niloticus)

Irisin, a secreted myokine generated by fibronectin type III domain-containing protein 5, has recently shown the potential to alleviate inflammation. Cholecystokinin-octapeptide (CCK-8) is closely associated with the inflammatory factor TNF-α, a central cytokine in inflammatory reactions. However, the interactions between irisin and CCK-8 in regulating TNF-α production and the underlying mechanism have not yet been elucidated. In the present study, irisin treatment inhibited the basal and the CCK-8-induced TNF-α production in vivo. Additionally, neutralizing circulating irisin using an irisin antiserum significantly augmented the CCK-8-induced stimulation of TNF-α levels. Moreover, the incubation of head kidney cells with irisin or CCK-8 has opposite effects on TNF-α secretion. Notably, irisin treatment inhibited basal and CCK-8-stimulated TNF-α release and gene transcription in head kidney cells. Mechanistically, the inhibitory actions of irisin on basal and CCK-8-induced TNF-α production could be negated by co-administered with the selective integrin αVβ5 inhibitor cilengitide. In addition, the inhibitory effect of irisin on basal and CCK-8-triggered TNF-α production could be abolished by the inhibition of the nuclear factor-kappa B (NF-κB) signaling pathway. Furthermore, irisin impeded CCK-8-induced phosphorylation and degradation of IκBα, simultaneously inhibiting NF-κB phosphorylation, preventing its translocation into the nucleus, and suppressing its DNA-binding activity induced by CCK-8. Collectively, these results suggest that the inhibitory effect of irisin on TNF-α production caused by CCK-8 is mediated via the integrin αVβ5-NF-κB signaling pathways in tilapia.

Musculoskeletal health in children and adolescents

The purpose of this narrative review was to investigate the key determinants of musculoskeletal health in childhood and adolescence, with particular attention to the role of physical activity. First, we examined the importance of bone modeling and remodeling in maintaining the bone health and the integrity and mechanical characteristic of the skeleton. In addition, we reported the evidence on an appropriate calcium and vitamin D intake, as well as local load variation in achieving proper peak bone mass. Proteomic and transcriptomic studies identified the skeletal muscle "secretoma", consisting of several myokines involved in endocrine and paracrine functions. Among these, we explored the role of irisin, a myokine involved in the muscle-bone crosstalk, and in the regulation of metabolic pathways. It is known that physical activity during growing positively impacts on skeleton and can protect by bone loss in adulthood. However, there are still concerns about the optimal interval duration and exercise intensity, particularly at the pubertal growth spurt which represents a window of opportunity to increase skeletal strength. We reported data from clinical trials performed in the last 5 years analyzing the impact of the type and timing of physical activity during childhood on skeletal development. Finally, we reported recent data on the significance of physical activity in some rare diseases.

Mitophagy-dependent cardioprotection of resistance training on heart failure

Resistance exercise is an indispensable mode of exercise rehabilitation for heart failure. Here we elucidate the cardiac effects of resistance training alone or combined with different aerobic trainings on heart failure and explore the critical regulation of mitophagy. The chronic heart failure model was constructed by transverse aortic constriction surgery, followed by 8 wk of resistance training (RT), moderate-intensity continuous training combined with resistance training (MRT), and high-intensity interval training combined with resistance training (HRT), and subsequently analyzed the changes of maximum load, cardiac structure and function, and myocardial mitophagic activity. The role and signaling of mitophagy in exercise protection of heart failure were investigated by knockdown of Hif1α and Parkin genes in primary neonatal cardiomyocytes. RT and especially MRT improved maximum load (P < 0.0001), myocardial morphology and fibrosis (P < 0.0001), reduced left ventricular diameter and enhanced left ventricular systolic function (P < 0.01), and enhanced myocardial mitophagic activity and HIF1α expression (P < 0.05) in heart failure mice. However, HRT had no obvious protective effect on ventricular diameter and function or mitophagy. The abilities of exercise stimulation to regulate reactive oxygen species, adenosine triphosphate, and brain natriuretic peptide were impaired after knockdown of Hif1α and Parkin genes inhibited mitophagy in failing cardiomyocytes (P < 0.05). Different exercise modalities provide discrepant cardiovascular effects on heart failure, and MRT exhibits optimal protection. The HIF1α-Parkin-mitophagy pathway is involved in the protection and regulation of exercise on heart failure.NEW & NOTEWORTHY Impaired myocardial mitophagy is implicated in the pathogenesis of heart failure. Resistance training alone or combined with different aerobic trainings provide discrepant cardiovascular effects on heart failure, and the cardioprotective function depends on HIF1α-Parkin-mitophagy pathway.

Inhibition of integrin alpha v/beta 5 mitigates the protective effect induced by irisin in hemorrhage

INTRODUCTION

Irisin plays an important role in regulating tissue stress, cardiac function, and inflammation. Integrin αvβ5 was recently identified as a receptor for irisin to elicit its physiologic function. It remains unknown whether integrin αvβ5 is required for irisin's function in modulating the physiologic response to hemorrhage. The objective of this study is to examine if integrin αvβ5 contributes to the effects of irisin during the hemorrhagic response.

METHODS

Hemorrhage was induced in mice by achieving a mean arterial blood pressure of 35-45 mmHg for one hour, followed by two hours of resuscitation. Irisin (0.5  μg/kg) was administrated to assess its pharmacologic effects in hemorrhage. Cilengitide, a cyclic Arg-Gly-Asp peptide (cRGDyK) which is an inhibitor of integrin αvβ5, or control RGDS (1 mg/kg) was administered with irisin. In another cohort of mice, the irisin-induced protective effect was examined after knocking down integrin β5 with nanoparticle delivery of integrin β5 sgRNA using CRSIPR/Cas-9 gene editing. Cardiac function and hemodynamics were measured using echocardiography and femoral artery catheterization, respectively. Systemic cytokine releases were measured using Enzyme-linked immunosorbent assay (ELISA). Histological analyses were used to determine tissue damage in myocardium, skeletal muscles, and lung tissues. Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) was carried out to assess apoptosis in tissues.

RESULTS

Hemorrhage induced reduction of integrin αvβ5 in skeletal muscles and repressed recovery of cardiac performance and hemodynamics. Irisin treatment led to significantly improved cardiac function, which was abrogated by treatment with Cilengitide or knockdown of integrin β5. Furthermore, irisin resulted in a marked suppression of tumor necrosis factor-α (TNF-α) and interleukin-1 (IL-1), muscle edema, and inflammatory cells infiltration in myocardium and skeletal muscles, which was attenuated by Cilengitide or knockdown of integrin β5. Irisin-induced reduction of apoptosis in the myocardium, skeletal muscles, and lung, which were attenuated by either the inhibition of integrin αvβ5, or knockdown of integrin β5.

CONCLUSION

Integrin αvβ5 plays an important role for irisin in modulating the protective effect during hemorrhage.

3,4-benzo[a]pyrene aggravates myocardial infarction injury by activating NLRP3-related pyroptosis through PINK1/Parkin-mitophagy-mPTP opening axis

BACKGROUND

Air pollution is an important and interventionable risk factor for cardiovascular disease. Air pollution exposure, even for a short-term exposure, is conspicuously relevant to increased risk of myocardial infarction (MI) mortality and clinical evidence has shown that air pollution particulate matter (PM) induces the aggravation of AMI. 3,4-benzo[a]pyrene (BaP), an extremely toxic polycyclic aromatic hydrocarbon (PAH) and a common component of PM, is listed as one of the main objects of environmental pollution monitoring. Both epidemiological and toxicological studies suggest that BaP exposure may be associated with cardiovascular disease. Since PM is significantly associated with the increased risk of MI mortality, and BaP is an important component of PM associated with cardiovascular disease, we intend to investigate the effect of BaP on MI models.

METHODS

The MI mouse model and the oxygen and glucose deprivation (OGD) H9C2 cell model were used to investigate the effect of BaP in MI injury. The involvement of mitophagy and pyroptosis in regulating deterioration of cardiac function and aggravation of MI injury induced by BaP was comprehensively evaluated.

RESULTS

Our study shows that BaP exacerbates MI injury in vivo and in vitro, a result based on BaP-induced NLRP3-related pyroptosis. In addition, BaP can inhibit PINK1/Parkin dependent mitophagy through the aryl hydrocarbon receptor (AhR), thus the mitochondrial permeability transition pore (mPTP) was induced to open.

CONCLUSION

Our results suggest a role for the BaP from air pollution in MI injury aggravation and reveal that BaP aggravates MI injury by activating NLRP3-related pyroptosis via the PINK1/Parkin-mitophagy-mPTP opening axis.

The Role of Swelling in the Regulation of OPA1-Mediated Mitochondrial Function in the Heart In Vitro

Optic atrophy-1 (OPA1) plays a crucial role in the regulation of mitochondria fusion and participates in maintaining the structural integrity of mitochondrial cristae. Here we elucidate the role of OPA1 cleavage induced by calcium swelling in the presence of Myls22 (an OPA1 GTPase activity inhibitor) and TPEN (an OMA1 inhibitor). The rate of ADP-stimulated respiration was found diminished by both inhibitors, and they did not prevent Ca2+-induced mitochondrial respiratory dysfunction, membrane depolarization, or swelling. L-OPA1 cleavage was stimulated at state 3 respiration; therefore, our data suggest that L-OPA1 cleavage produces S-OPA1 to maintain mitochondrial bioenergetics in response to stress.

Exerkines and redox homeostasis

Exercise physiology has gained increasing interest due to its wide effects to promote health. Recent years have seen a growth in this research field also due to the finding of several circulating factors that mediate the effects of exercise. These factors, termed exerkines, are metabolites, growth factors, and cytokines secreted by main metabolic organs during exercise to regulate exercise systemic and tissue-specific effects. The metabolic effects of exerkines have been broadly explored and entail a promising target to modulate beneficial effects of exercise in health and disease. However, exerkines also have broad effects to modulate redox signaling and homeostasis in several cellular processes to improve stress response. Since redox biology is central to exercise physiology, this review summarizes current evidence for the cross-talk between redox biology and exerkines actions. The role of exerkines in redox biology entails a response to oxidative stress-induced pathological cues to improve health outcomes and to modulate exercise adaptations that integrate redox signaling.

Exercise-Induced Autophagy Ameliorates Motor Symptoms Progressivity in Parkinson's Disease Through Alpha-Synuclein Degradation: A Review

This study reviews the molecular mechanism of exercise-induced autophagy/mitophagy and its possible mechanism in delaying motor symptoms progressivity in Parkinson's disease (PD). Relevant articles obtained from PubMed and EBSCOhost were reviewed. After analyzing the articles, it was found that autophagy can be induced by exercise and can possibly be activated through the AMPK-ULK1 pathway. Mitophagy can also be induced by exercise and can possibly be activated through PINK1/Parkin pathway and AMPK-dependent pathway. Moreover, exercise-induced autophagy can decrease the accumulation of toxic α-synuclein aggregates in PD and therefore can delay motor symptoms progressivity.

RhoA rescues cardiac senescence by regulating Parkin-mediated mitophagy

Heart failure is one of the leading causes of death worldwide. RhoA, a small GTPase, governs actin dynamics in various tissue and cell types, including cardiomyocytes; however, its involvement in cardiac function has not been fully elucidated. Here, we generated cardiomyocyte-specific RhoA conditional knockout (cKO) mice, which demonstrated a significantly shorter lifespan with left ventricular dilation and severely impaired ejection fraction. We found that the cardiac tissues of the cKO mice exhibited structural disorganization with fibrosis and also exhibited enhanced senescence compared with control mice. In addition, we show that cardiomyocyte mitochondria were structurally abnormal in the aged cKO hearts. Clearance of damaged mitochondria by mitophagy was remarkably inhibited in both cKO cardiomyocytes and RhoA-knockdown HL-1 cultured cardiomyocytes. In RhoA-depleted cardiomyocytes, we reveal that the expression of Parkin, an E3 ubiquitin ligase that plays a crucial role in mitophagy, was reduced, and expression of N-Myc, a negative regulator of Parkin, was increased. We further reveal that the RhoA-Rho kinase axis induced N-Myc phosphorylation, which led to N-Myc degradation and Parkin upregulation. Re-expression of Parkin in RhoA-depleted cardiomyocytes restored mitophagy, reduced mitochondrial damage, attenuated cardiomyocyte senescence, and rescued cardiac function both in vitro and in vivo. Finally, we found that patients with idiopathic dilated cardiomyopathy without causal mutations for dilated cardiomyopathy showed reduced cardiac expression of RhoA and Parkin. These results suggest that RhoA promotes Parkin-mediated mitophagy as an indispensable mechanism contributing to cardioprotection in the aging heart.

Irisin and ALCAT1 mediated aerobic exercise-alleviated oxidative stress and apoptosis in skeletal muscle of mice with myocardial infarction

Skeletal muscle in patients with heart failure (HF) exhibits altered structure, function and metabolism. Myocardial infarction (MI) is the most common cause of HF. Oxidative stress and cell apoptosis are involved in the pathophysiology of MI/HF-induced skeletal muscle atrophy. It is well recognized that aerobic exercise (AE) could prevent skeletal muscle atrophy after MI, but the underlying mechanism and molecular targets are still not fully clarified. In this study, Fndc5^-/- and Alcat1^-/- mice were used to establish the MI model and subjected to six weeks of moderate-intensity AE. C2C12 cells were treated with H₂O₂ and recombinant human Irisin (rhIrisin), or transduced with a lentiviral vector to mediate the overexpression of ALCAT1 (LV-Alcat1). Results showed that MI reduced Irisin expression and antioxidant capacity of skeletal muscle, increased ALCAT1 expression, induced protein degradation and cell apoptosis, which were partly reversed by AE; Knockout of Fndc5 further aggravated MI-induced oxidative stress and cell apoptosis in skeletal muscle, and partly weakened the beneficial effects of AE. In contrast, knockout of Alcat1 reduced MI-induced oxidative stress and cell apoptosis and strengthened the beneficial effects of AE. rhIrisin and AICAR intervention inhibited ALCAT1 expression, oxidative stress and cell apoptosis, which induced by H₂O₂ or LV-Alcat1 in C2C12 cells. These findings reveal that AE could alleviate the levels of oxidative stress and apoptosis in skeletal muscle following MI, partly via up-regulating Irisin and inhibiting ALCAT1 expression.

Effects of combined aerobic and resistance training on gut microbiota and cardiovascular risk factors in physically active elderly women: A randomized controlled trial

Background: Exercise can modulate gut microbiota and lower the risk of cardiovascular disease (CVD). However, the association between exercise-induced changes in gut microbiota and CVD risk have not been investigated.

Objective: This study determined the effects of exercise training on CVD risk and gut microbiota in physically active elderly women and whether exercise-induced gut microbiota changes were associated with CVD risk.

Methods: An 8-week randomized controlled trial was conducted with 14 elderly women assigned to exercise group (n = 8) or control group (n = 6). Physical function, sarcopenic obesity, and metabolic syndrome were evaluated as components of CVD risk. Gut microbiota composition was determined using 16S rRNA gene sequencing. Repeated-measures analysis of variance was used to examine intra-group and inter-group differences.

Results: A significant group × time interaction was observed for chair sit-and-reach (F = 8.262, p = 0.014), single-leg standing with eyes closed (F = 7.340, p = 0.019), waist circumference (F = 6.254, p = 0.028), and body fat mass (F = 12.263, p = 0.004), for which the exercise group showed improved trends. The exercise group exhibited significant improvements in skeletal muscle mass (p = 0.041) and fasting blood glucose (p = 0.017). Regarding gut microbiota, a significant interaction was observed for the class Betaproteobacteria (F = 6.822, p = 0.023) and genus Holdemania (F = 4.852, p = 0.048).

Conclusion: The 8-week exercise training improved physical function, lowered CVD risk, and modulated relative abundance of gut microbiota associated with CVD in physically active elderly women.

Effect of exercise training on cardiac mitochondrial respiration, biogenesis, dynamics, and mitophagy in ischemic heart disease

Objective

Cardiac mitochondrial dysfunction was found in ischemic heart disease (IHD). Hence, this study determined the effects of exercise training (ET) on cardiac mitochondrial respiration and cardiac mitochondrial quality control in IHD.

Methods

A narrative synthesis was conducted after searching animal studies written in English in three databases (PubMed, Web of Science, and EMBASE) until December 2020. Studies that used aerobic exercise as an intervention for at least 3 weeks and had at least normal, negative (sedentary IHD), and positive (exercise-trained IHD) groups were included. The CAMARADES checklist was used to check the quality of the included studies.

Results

The 10 included studies (CAMARADES score: 6–7/10) used swimming or treadmill exercise for 3–8 weeks. Seven studies showed that ET ameliorated cardiac mitochondrial respiratory function as manifested by decreased reactive oxygen species (ROS) production and increased complexes I-V activity, superoxide dismutase 2 (SOD2), respiratory control ratio (RCR), NADH dehydrogenase subunits 1 and 6 (ND1/6), Cytochrome B (CytB), and adenosine triphosphate (ATP) production. Ten studies showed that ET improved cardiac mitochondrial quality control in IHD as manifested by enhanced and/or controlled mitochondrial biogenesis, dynamics, and mitophagy. Four other studies showed that ET resulted in better cardiac mitochondrial physiological characteristics.

Conclusion

Exercise training could improve cardiac mitochondrial functions, including respiration, biogenesis, dynamics, and mitophagy in IHD.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=226817, identifier: CRD42021226817.

Role of irisin in physiology and pathology

Irisin, out-membrane part of fibronectin type III domain-containing 5 protein (FNDC5), was activated by Peroxisome proliferator-activated receptor γ (PPARγ) coactivator-1α (PGC-1α) during physical exercise in skeletal muscle tissues. Most studies have reported that the concentration of irisin is highly associated with health status. For instance, the level of irisin is significantly lower in patients with obesity, osteoporosis/fractures, muscle atrophy, Alzheimer's disease, and cardiovascular diseases (CVDs) but higher in patients with cancer. Irisin can bind to its receptor integrin αV/β5 to induce browning of white fat, maintain glucose stability, keep bone homeostasis, and alleviate cardiac injury. However, it is unclear whether it works by directly binding to its receptors to regulate muscle regeneration, promote neurogenesis, keep liver glucose homeostasis, and inhibit cancer development. Supplementation of recombinant irisin or exercise-activated irisin might be a successful strategy to fight obesity, osteoporosis, muscle atrophy, liver injury, and CVDs in one go. Here, we summarize the publications of FNDC5/irisin from PubMed/Medline, Scopus, and Web of Science until March 2022, and we review the role of FNDC5/irisin in physiology and pathology.

Irisin Regulates Cardiac Responses to Exercise in Health and Diseases: a Narrative Review

Exercise has been recognized as an important non-pharmacological approach for the prevention, treatment, and rehabilitation of cardiovascular diseases, but the mechanisms of exercise in promoting cardiovascular health remain unclear. Exercise generates cardiac benefits via stimulating muscle to secret hundreds of myokines that directly enter circulation and target heart tissue. Therefore, inter-organ communication between skeletal muscle and heart may be one important regulating pattern, and such communication can occur through secretion of molecules, frequently known as myokines. Irisin, a newly identified myokine, is cleaved from fibronectin type III domain-containing protein 5 (FNDC5) and secreted by the stimulation of exercise. Recently, accumulating evidence focusing on the interaction between irisin and cardiac function has been reported. This review highlights the molecular signaling by which irisin regulates the benefits of exercise on cardiac function both in physiological and pathological process, and discusses the clinical potential of irisin in treating heart diseases. Exercise generates various cardiovascular benefits through stimulating skeletal muscle to secrete irisin. The exercise "hormone" irisin, both produced by exercise or recombinant form, exerts therapeutic effects in a group of cardiovascular disorders including heart failure, myocardial infarction, atherosclerosis and hypertension. However, the molecular mechanisms involved remain ambiguous.This review highlights the most up-to-date findings to bridge the gap between exercise, irisin and cardiovascular diseases, and discusses the potential clinical prospect of irisin.

Exercise-induced modulation of myokine irisin in bone and cartilage tissue—Positive effects on osteoarthritis: A narrative review

Osteoarthritis is a chronic degenerative musculoskeletal disease characterized by pathological changes in joint structures along with the incidence of which increases with age. Exercise is recommended for all clinical treatment guidelines of osteoarthritis, but the exact molecular mechanisms are still unknown. Irisin is a newly discovered myokine released mainly by skeletal muscle in recent years—a biologically active protein capable of being released into the bloodstream as an endocrine factor, the synthesis and secretion of which is specifically induced by exercise-induced muscle contraction. Although the discovery of irisin is relatively recent, its role in affecting bone density and cartilage homeostasis has been reported. Here, we review the production and structural characteristics of irisin and discuss the effects of the different types of exercise involved in the current study on irisin and the role of irisin in anti-aging. In addition, the role of irisin in the regulation of bone mineral density, bone metabolism, and its role in chondrocyte homeostasis and metabolism is reviewed. A series of studies on irisin have provided new insights into the mechanisms of exercise training in improving bone density, resisting cartilage degeneration, and maintaining the overall environmental homeostasis of the joint. These studies further contribute to the understanding of the role of exercise in the fight against osteoarthritis and will provide an important reference and aid in the development of the field of osteoarthritis prevention and treatment.

Mechanism of CNS regulation by irisin, a multifunctional protein

Exercise not only builds up our body but also improves cognitive function. Skeletal muscle secretes myokine during exercise as a large reservoir of signaling molecules, which can be considered as a medium between exercise and brain health. Irisin is a circulating myokine derived from the Fibronectin type III domain-containing protein 5 (FNDC5). Irisin regulates energy metabolism because it can stimulate the "Browning" of white adipose tissue. It has been reported that irisin can cross the blood-brain barrier and increase the expression of a brain-derived neurotrophic factor (BDNF) in the hippocampus, which improves learning and memory. In addition, the neuroprotective effect of irisin has been verified in various disease models. Therefore, this review summarizes how irisin plays a neuroprotective role, including its signal pathway and mechanism. In addition, we will briefly discuss the therapeutic potential of irisin for neurological diseases.

Irisin is an Effector Molecule in Exercise Rehabilitation Following Myocardial Infarction (Review)

Background: Regular exercise is an effective non-pharmacological therapy for treatment and prevention of cardiovascular disease (CVD). The therapeutic benefits of exercise are mediated partly through improved vascular and increase in metabolic health. Release of exercise-responsive myokines, including irisin, is associated with beneficial effects of exercise in CVD patients.

Observations: The present review provides an overview of the role of exercise in cardiac rehabilitation of patients with myocardial infarction (MI). Further, the role of irisin as a motion-responsive molecule in improving vascular and metabolic health is explored. Possible mechanism of cardioprotective effect of irisin-mediated exercise on myocardial infarction are also summarized in this review.

Conclusion and significance of the review: Irisin is associated with reduced inflammation, antioxidant properties, and anti-apoptotic effect, implying that it is a potential key mediator of the beneficial effects of exercise on vascular and metabolic health. The findings show that irisin is a promising therapeutic target for treatment of patients with cardiovascular disease, particularly post-MI. Further research should be conducted to elucidate the potential mechanisms of cardioprotective effects of irisin and explored whether irisin induced by exercise exerts rehabilitation effects post-MI.

PINK1/Parkin-mediated mitophagy in cardiovascular disease: From pathogenesis to novel therapy

Cardiovascular disease(CVD)is one of the predominant causes of death and morbidity. Mitochondria play a key role in maintaining cardiac energy metabolism. However, mitochondrial dysfunction leads to excessive production of ROS, resulting in oxidative damage to cardiomyocytes and contributing to a variety of cardiovascular diseases. In such a case, the clearance of impaired mitochondria is necessary. Currently, most studies have indicated an essential role for mitophagy in maintaining cardiac homeostasis and regulating CVD-related metabolic transition. Recent studies have implicated that PTEN-induced putative kinase 1 (PINK1)/Parkin-mediated mitophagy has been implicated in maintaining cardiomyocyte homeostasis. Here, we discuss the physiological and pathological roles of PINK1/Parkin-mediated mitophagy in the cardiovascular system, as well as potential therapeutic strategies based on PINK1/Parkin-mediated mitophagy modulation, which are of great significance for the prevention and treatment of cardiovascular diseases.

Exercise training differently improve cardiac function and regulate myocardial mitophagy in ischemic and pressure-overloaded heart failure mice

NEW FINDINGS

What is the central question of this study? The cardioprotective effects of different aerobic exercises on chronic heart failure with different etiologies and whether mitophagy is involved remain elusive. What is the main finding and its importance? Moderate-intensity continuous training may be the "optimum" modality for improving cardiac structure and function in ischemic heart failure, while both moderate-intensity continuous training and high-intensity interval training were suitable for pressure-overloaded heart failure. Various mitophagy pathways especially PRKN-dependent pathways participated in the protective effects of exercise on heart failure.

ABSTRACT

The cardioprotective effects of different aerobic exercises on chronic heart failure with different etiologies and whether mitophagy is involved remain elusive. In the current research, left anterior descending ligation and transverse aortic constriction surgeries were used to establish mice models of heart failure, followed by 8 weeks of moderate-intensity continuous training (MICT) and high-intensity interval training (HIIT). The results showed that MICT significantly improved ejection fraction (P < 0.05) and fractional shortening (P < 0.05), mitigated left ventricular end-systolic dimension (P < 0.01), brain natriuretic peptide (P < 0.0001), and fibrosis (P < 0.0001), while HIIT only decreased brain natriuretic peptide (P < 0.0001) and fibrosis (P < 0.0001) for ischemic heart failure. Both MICT and HIIT significantly increased ejection fraction (P < 0.0001) and fractional shortening (MICT: P < 0.001, HIIT: P < 0.0001), reduced left ventricular end-diastolic and end-systolic dimension, brain natriuretic peptide (P < 0.0001), and fibrosis (MICT: P < 0.01, HIIT: P < 0.0001), even HIIT was better in reducing brain natriuretic peptide on pressure-overloaded heart failure. Myocardial autophagy and mitophagy were compromised in heart failure, exercises improved myocardial autophagic flux and mitophagy inconsistently in heart failure with different etiologies. Significant correlations were found between multiple mitophagy pathways and cardioprotection of exercises. Collectively, MICT may be the "optimum" modality for ischemic heart failure, both MICT and HIIT (especially HIIT) were suitable for pressure-overloaded heart failure. Exercises differently improved myocardial autophagy/mitophagy and multiple mitophagy-related pathways were closely implicated in cardioprotection of exercises for chronic heart failure. This article is protected by copyright. All rights reserved.

Irisin at the crossroads of inter-organ communications: Challenge and implications

The physiological functions of organs are intercommunicated occurring through secreted molecules. That exercise can improve the physiological function of organs or tissues is believed by secreting myokines from muscle to target remote organs. However, the underlying mechanism how exercise regulates the inter-organ communications remains incompletely understood yet. A recently identified myokine-irisin, primarily found in muscle and adipose and subsequently extending to bone, heart, liver and brain, provides a new molecular evidence for the inter-organ communications. It is secreted under the regulation of exercise and mediates the intercommunications between exercise and organs. To best our understanding of the regulatory mechanism, this review discusses the recent evidence involving the potential molecular pathways of the inter-organ communications, and the interactions between signalings and irisin in regulating the impact of exercise on organ functions are also discussed.

Establishing Equivalent Aerobic Exercise Parameters Between Early-Stage Parkinson's Disease and Pink1 Knockout Rats

BACKGROUND

Rodent Parkinson's disease (PD) models are valuable to interrogate neurobiological mechanisms of exercise that mitigate motor impairment. Translating these mechanisms to human PD must account for physical capabilities of the patient.

OBJECTIVE

To establish cardiovascular parameters as a common metric for cross-species translation of aerobic exercise impact.

METHOD

We evaluated aerobic exercise impact on heart rate (HR) in 21 early-stage PD subjects (Hoehn Yahr ≤1.5) exercising in non-contact boxing training for ≥3 months, ≥3x/week. In 4-month-old Pink1 knockout (KO) rats exercising in a progressively-increased treadmill speed regimen, we determined a specific treadmill speed that increased HR to an extent similar in human subjects.

RESULTS

After completing aerobic exercise for ∼30 min, PD subjects had increased HR∼35% above baseline (∼63% maximum HR). Motor and cognitive test results indicated the exercising subjects completed the timed up and go (TUG) and trail-making test (TMT-A) in significantly less time versus exercise-naïve PD subjects. In KO and age-matched wild-type (WT) rats, treadmill speeds of 8-10 m/min increased HR up to 25% above baseline (∼67% maximum HR), with no further increases up to 16 m/min. Exercised KO, but not WT, rats showed increased locomotor activity compared to an age-matched exercise-naïve cohort at 5 months old.

CONCLUSION

These proof-of-concept results indicate HR is a cross-species translation parameter to evaluate aerobic exercise impact on specific motor or cognitive functions in human subjects and rat PD models. Moreover, a moderate intensity exercise regimen is within the physical abilities of early-stage PD patients and is therefore applicable for interrogating neurobiological mechanisms in rat PD models.