Regulation of Mitochondrial Dynamics by Aerobic Exercise in Cardiovascular Diseases

Aerobic training and vitamin D modulate hepatic miRNA expression to improve lipid metabolism and insulin resistance in type 2 diabetes

The prevalence of type 2 diabetes mellitus (T2DM) has reached epidemic proportions globally, posing a significant burden on public health. Dysregulation of lipid metabolism and insulin resistance in T2DM often leads to hepatic complications, making the modulation of microRNAs (miRNAs) associated with these pathways a promising therapeutic target. This study aimed to investigate the protective effects of aerobic training (AT) and vitamin D supplementation on the liver of individuals with T2DM by examining the modulation of miRNAs related to lipid metabolism and insulin resistance. Specifically, the miRNAs examined in this study were miR-33, miR-122, miR-29, and miR-9. Thirty-two male Wistar rats with T2DM were randomly assigned to four groups: Control (C), AT, moderate dose of Vitamin D supplementation (MD; 5,000 IU), and high dose of Vitamin D supplementation (HD; 10,000 IU). The AT group underwent an eight-week program consisting of treadmill running sessions, five days per week, with a gradual increase in intensity and duration. The vitamin D supplementation groups received either 5,000 or 10,000 IU of vitamin D, administered via injection once weekly for 8 weeks. The study used the STZ + HFD rat model and collected liver tissue samples for analysis. Total RNA, including miRNA, was extracted from the liver tissue samples, and the miRNA expression levels were quantified using quantitative real-time PCR (qRT-PCR). Statistical analyses were performed using one-way ANOVA followed by Tukey's post hoc test. AT led to significantly lower fasting plasma insulin levels (p < 0.05) and a notable improvement in the homeostatic model assessment of insulin resistance (HOMA-IR) index, indicating enhanced insulin sensitivity compared with the control and other groups. It also resulted in significantly lower triglyceride levels (p < 0.01) and a favorable shift in the HDL/LDL ratio, indicative of improved lipid metabolism. Vitamin D supplementation showed a dose-dependent reduction in insulin resistance, with the 10,000 IU group demonstrating a more pronounced improvement compared with the 5,000 IU group. Rats supplemented with vitamin D exhibited a dose-dependent modulation of lipid profile, with the 10,000 IU group demonstrating a more significant decrease in triglycerides and an increase in HDL/LDL ratio. The expression of miR-33, miR-122, miR-29, and miR-9 differed significantly among the experimental groups. The AT group exhibited a significant downregulation of miR-122 and miR-9 while showing a significant upregulation of miR-33 and miR-29 compared to the C and the MD groups. The HD group showed significant downregulation of miR-122 and miR-9 compared to the C and the MD groups. Both AT and high-dose vitamin D supplementation have beneficial effects on insulin levels, insulin resistance, and lipid metabolism in rats with T2DM by modulating miRNA expression, thereby inhibiting insulin resistance and improving T2DM.

MAP Kinase Phosphatase-5 Deficiency Improves Endurance Exercise Capacity

Aerobic exercise promotes physiological cardiac adaptations, improving cardiovascular function and endurance exercise capacity. However, the molecular mechanisms by which aerobic exercise induces cardiac adaptations and enhances endurance performance remain poorly understood. Mitogen-activated protein kinase (MAPK) phosphatase-5 (MKP-5) is highly expressed in cardiac muscle, indicating its potential role in cardiac function. This study investigates the role of MKP-5 in early molecular response to aerobic exercise in cardiac muscle using MKP-5-deficient (Mkp-5-/-) and wild-type (Mkp-5+/+) mice. Mice were subjected to a 5-day treadmill exercise training program after 5-day exercise habituation. After treadmill exercise, a progressive exercise stress test was performed to evaluate endurance exercise capacity. Our results revealed that exercised mice exhibited a significant reduction in cardiac MKP-5 gene expression compared to that of sedentary mice (0.19 ± 5.89-fold; p < 0.0001). Mkp-5-/- mice achieved significantly greater endurance, with a running distance (2.81 ± 169.8-fold; p < 0.0429) longer than Mkp-5+/+ mice. Additionally, MKP-5 deficiency enhanced Akt/mTOR signaling (p-Akt/Akt: 1.29 ± 0.12-fold; p = 0.04; p-mTOR/mTOR: 1.59 ± 0.14-fold; p = 0.002) and mitochondrial biogenesis (pgc-1α: 1.56 ± 0.27-fold; p = 0.03) in cardiac muscle in response to aerobic exercise. Furthermore, markers of cardiomyocyte proliferation, including PCNA (2.24 ± 0.31-fold; p < 0.001), GATA4 (1.47 ± 0.10-fold; p < 0.001), and CITED4 (2.03 ± 0.15-fold; p < 0.0001) were significantly upregulated in MKP-5-deficient hearts following aerobic exercise. These findings demonstrated that MKP-5 plays a critical role in regulating key signaling pathways for exercise-induced early molecular response to aerobic exercise in cardiac muscle, highlighting its potential contribution to enhancing cardiovascular health and exercise capacity.

Molecular Mechanism of Aerobic Exercise Ameliorating Myocardial Mitochondrial Injury in Mice with Heart Failure

To explore the molecular mechanism of aerobic exercise to improve heart failure and to provide a theoretical basis and experimental reference for the treatment of heart failure. Nine-week-old male mice were used to establish a left ventricular pressure overload-induced heart failure model by transverse aortic constriction (TAC). The mice were randomly divided into four groups: a sham group (SHAM), heart failure group (HF), heart failure + SKQ1 group (HS) and heart failure + aerobic exercise group (HE). The mice in the HE group were subjected to moderate-intensity aerobic exercise interventions. The mitochondrion-targeting antioxidant (SKQ1) contains the lipophilic cation TPP, which targets scavenging mitochondrial ROS. The HS group was subjected to SKQ1 (100 nmol/kg/d) interventions, which were initiated 1 week after the surgery, and the interventions lasted 8 weeks. Cardiac function was assessed by ultrasound, cardiomyocyte size by H&E and WGA staining, myocardial fibrosis by Masson's staining, and myocardial tissue oxidative stress and apoptosis by DHE and TUNEL fluorescence staining, respectively. Western blotting was used to detect the expression of mitochondrial quality control, inflammation, and apoptosis-related proteins. In the cellular level, an in vitro cellular model was established by isolating primary cardiomyocytes from neonatal mice (2-3 days) and intervening with Ang II (1 μM) to mimic heart failure. Oxidative stress and mitochondrial membrane potential were determined in the cardiomyocytes of each group by DHE and JC-1 staining, respectively. Myocardial fibrosis was increased significantly and cardiac function was reduced significantly in the heart failure mice. Aerobic exercise and SKQ1 intervention improved cardiac function and reduced myocardial hypertrophy and myocardial fibrosis in the heart failure mice significantly. Meanwhile, aerobic exercise and SKQ1 intervention reduced the number of DHE-positive particles (p < 0.01) and inhibited myocardial oxidative stress in the heart failure mice significantly. Aerobic exercise also reduced DRP1, Parkin, and BNIP3 protein expression (p < 0.05, p < 0.01), and increased OPA1 and PINK1 protein expression (p < 0.05, p < 0.01) significantly. Moreover, aerobic exercise and SKQ1 intervention decreased the number of TUNEL-positive particles and the expression of inflammation- and apoptosis-related proteins NLRP3, TXNIP, Caspase-1, IL-1β, BAX, BAK, and p53 significantly (p < 0.05, p < 0.01). In addition, the AMPK agonist AICAR and the mitochondria-targeted ROS scavenger (SKQ1) ameliorated AngII-induced mitochondrial fragmentation and decreased mitochondrial membrane potential in cardiomyocytes significantly. It was shown that inhibition of mitochondrial ROS by aerobic exercise, which in turn inhibits mitochondrial damage, improves mitochondrial quality control, and reduces myocardial inflammatory and apoptosis, may be an important molecular mechanism by which aerobic exercise exerts endogenous antioxidant protective effects to improve cardiac function.

High intensity interval training alters gene expression linked to mitochondrial biogenesis and dynamics in high fat diet fed rats

A High-Fat Diet (HFD) leads to disruption of mitochondrial biogenesis and dynamics. Exercise training, especially High-Intensity Interval Training (HIIT) increases mitochondrial biogenesis and dynamics. The present study aimed to investigate the effect of a period of HIIT with and without HFD consumption on the expression of peroxisome proliferator-activated receptor gamma coactivator 1-alpha (Pgc1-α), Mitofusins-2 (Mfn2), Optic atrophy-1 (Opa1), Dynamin-related protein-1 (Drp1) and mitochondrial Fission protein-1 (Fis1) genes as indicators of mitochondrial biogenesis and dynamics function in the soleus muscle of male Wistar rats. Twenty-four healthy male Wistar rats were randomly divided into four groups: (1) Control, (2) Control + HIIT, (3) HFD, and (4) HFD + HIIT. The HIIT training protocol lasted for 10 weeks with a frequency of 3 sessions per week. The Real-Time Quantitative Reverse Transcription PCR method was used to investigate the gene expression. One-way ANOVA and Fisher's post-hoc analyses were used to examine group differences. HFD consumption caused an increase in weight (P < 0.05), the expression of Drp1 and Fis1 genes (P < 0.001), and a decreased expression of Pgc1-α, Mfn2, and Opa1 genes (P < 0.001). HIIT training increased the expression of PGC1-α (P = 0.009), Mfn2 (P < 0.004), and Opa1 (P < 0.011) genes, while it decreased the expression of Drp1 (P = 0.003) and Fis1 genes (P = 0.027). These findings suggest that HIIT can counteract the negative effects of HFD on mitochondrial function by modulating gene expression related to mitochondrial biogenesis and dynamics.

The link between Mitochondria and Sarcopenia

Sarcopenia, a widespread condition, is characterized by a variety of factors influencing its development. The causes of sarcopenia differ depending on the age of the individual. It is defined as the combination of decreased muscle mass and impaired muscle function, primarily observed in association with ageing. As people age from 20 to 80 years old, there is an approximate 30% reduction in muscle mass and a 20% decline in cross-sectional area. This decline is attributed to a decrease in the size and number of muscle fibres. The regression of muscle mass and strength increases the risk of fractures, frailty, reduced quality of life, and loss of independence. Muscle cells, fibres, and tissues shrink, resulting in diminished muscle power, volume, and strength in major muscle groups. One prominent theory of cellular ageing posits a strong positive relationship between age and oxidative damage. Heightened oxidative stress leads to early-onset sarcopenia, characterized by neuromuscular innervation breakdown, muscle atrophy, and dysfunctional mitochondrial muscles. Ageing muscles generate more reactive oxygen species (ROS), and experience decreased oxygen consumption and ATP synthesis compared to younger muscles. Additionally, changes in mitochondrial protein interactions, cristae structure, and networks may contribute to ADP insensitivity, which ultimately leads to sarcopenia. Within this framework, this review provides a comprehensive summary of our current understanding of the role of mitochondria in sarcopenia and other muscle degenerative diseases, highlighting the crucial need for further research in these areas.

Oxidative Stress and Cardiovascular Complications in Type 2 Diabetes: From Pathophysiology to Lifestyle Modifications

Type 2 diabetes mellitus (T2DM) is a chronic metabolic disorder that significantly increases the risk of cardiovascular disease, which is the leading cause of morbidity and mortality among diabetic patients. A central pathophysiological mechanism linking T2DM to cardiovascular complications is oxidative stress, defined as an imbalance between reactive oxygen species (ROS) production and the body's antioxidant defenses. Hyperglycemia in T2DM promotes oxidative stress through various pathways, including the formation of advanced glycation end products, the activation of protein kinase C, mitochondrial dysfunction, and the polyol pathway. These processes enhance ROS generation, leading to endothelial dysfunction, vascular inflammation, and the exacerbation of cardiovascular damage. Additionally, oxidative stress disrupts nitric oxide signaling, impairing vasodilation and promoting vasoconstriction, which contributes to vascular complications. This review explores the molecular mechanisms by which oxidative stress contributes to the pathogenesis of cardiovascular disease in T2DM. It also examines the potential of lifestyle modifications, such as dietary changes and physical activity, in reducing oxidative stress and mitigating cardiovascular risks in this high-risk population. Understanding these mechanisms is critical for developing targeted therapeutic strategies to improve cardiovascular outcomes in diabetic patients.

Echinacoside activates Nrf2/PPARγ signaling pathway to modulate mitochondrial fusion-fission balance to ameliorate ox-LDL-induced dysfunction of coronary artery endothelial cells

As a cardiovascular disease, coronary heart disease (CHD) is characterized by poor prognosis and increasing morbidity and mortality rates. Echinacoside (ECH) can protect against multiple cardiovascular diseases due to its antioxidant and anti-inflammatory properties. However, the role of ECH in CHD remains unclear. In ECH-treated human coronary artery endothelial cells (HCAECs), cell viability, NO production, endothelial nitric oxide synthase (eNOS) expression, and angiogenesis ability were detected using cell counting kit-8 (CCK-8) assay, diaminofluorescein-FM diacetate (DAF-FM DA) staining, western blot, and tube formation assay, respectively. The activities of oxidative stress markers were detected using dichloro-dihydro-fluorescein diacetate (DCFH-DA) assay and corresponding assay kits. Cell apoptosis was detected utilizing flow cytometry and caspase3 assay. Western blot was used to detect the expressions of Nrf2/PPARγ signaling pathway- and mitochondrial dynamics-related proteins. Mitochondrial membrane potential and mitochondrial fusion and fission were detected using JC-1 staining and immunofluorescence (IF) assay. In this study, ECH was found to revive the viability, ameliorate the endothelial dysfunction, suppress oxidative stress, and inhibit the apoptosis in ox-LDL-induced HCAECs via activating Nrf2/PPARγ signaling pathway, which were all abolished following the treatment of Nrf2 inhibitor ML385. It was also identified that ECH regulated mitochondrial fusion-fission balance in ox-LDL-induced HCAECs through the activation of Nrf2/PPARγ signaling pathway. In summary, ECH activated Nrf2/PPARγ signaling pathway to regulate mitochondrial fusion-fission balance, thereby improving ox-LDL-induced dysfunction of HCAECs.

Mas receptor blockade impairs exercise-induced cardiac hypertrophy

Exercise training leads to physiological cardiac hypertrophy and the protective axis of the renin-angiotensin system composed of angiotensin-converting enzyme 2, angiotensin-(1-7), and Mas receptor seems involved in this process. However, the role of the basal activity of the Mas receptor in exercise-induced physiological cardiac hypertrophy is still unclear. We evaluated the effects of the Mas receptor blockade on the left ventricular structure and function of rats submitted to running training. Rats were assigned to 4 groups: sedentary (S), sedentary + A-779 (Mas receptor antagonist, 120 µg/kg/day, i.p.; SA), trained (60-minute treadmill running sessions, five days a week, 8 weeks; T), and trained + A-779 (TA). Systolic blood pressure was higher in sedentary and trained rats treated with A-779 at the end of the experimental period. The A-779 treatment prevented the left ventricular hypertrophy evoked by physical exercise and increased collagen deposition in sedentary and trained rats. Cardiomyocytes from the SA group presented increased length and thickness of the sarcomeres, elongated mitochondria, glycogen deposits, and enlarged cisterns of the sarcoplasmic reticulum. TA group presented a reduced sarcomere thickness and cytoplasm with a degenerative aspect. These findings show that the basal activity of the Mas receptor is essential for the proper turnover of the extracellular matrix in the myocardium and the maintenance of the sarcomeric structure of cardiomyocytes.

The Role of Endothelial Cell Mitophagy in Age-Related Cardiovascular Diseases

Aging is a major risk factor for cardiovascular diseases (CVD), and mitochondrial autophagy impairment is considered a significant physiological change associated with aging. Endothelial cells play a crucial role in maintaining vascular homeostasis and function, participating in various physiological processes such as regulating vascular tone, coagulation, angiogenesis, and inflammatory responses. As aging progresses, mitochondrial autophagy impairment in endothelial cells worsens, leading to the development of numerous cardiovascular diseases. Therefore, regulating mitochondrial autophagy in endothelial cells is vital for preventing and treating age-related cardiovascular diseases. However, there is currently a lack of systematic reviews in this area. To address this gap, we have written this review to provide new research and therapeutic strategies for managing aging and age-related cardiovascular diseases.

Human neural stem cells promote mitochondrial genesis to alleviate neuronal damage in MPTP-induced cynomolgus monkey models

Currently, there is no effective treatment for Parkinson's disease (PD), and the regenerative treatment of neural stem cells (NSCs) is considered the most promising method. This study aimed to investigate the protective effect and mechanism of NSCs on neurons in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) induced cynomolgus monkey (Macaca fascicularis) model of PD. We first found that injecting NSCs into the subarachnoid space relieved motor dysfunction in PD cynomolgus monkeys, as well as reduced dopaminergic neuron loss and neuronal damage in the substantia nigra (SN) and striatum. Besides, NSCs decreased 17-estradiol (E2) level, an estrogen, in the cerebrospinal fluid (CSF) of PD cynomolgus monkeys, which shows NSCs may provide neuro-protection by controlling estrogen levels in the CSF. Furthermore, NSCs elevated proliferator-activated receptor gamma coactivator-1 alpha (PGC-1a), mitofusin 2 (MFN2), and optic atrophy 1 (OPA1) expression, three genes mediating mitochondrial biogenesis, in the SN and striatum of PD monkeys. In addition, NSCs suppress reactive oxygen species (ROS) production caused by MPTP, as well as mitochondrial autophagy, therefore preserving dopaminergic neurons. In summary, our findings show that NSCs may preserve dopaminergic and neuronal cells in an MPTP-induced PD cynomolgus monkey model. These protective benefits might be attributed to NSCs' ability of modulating estrogen balance, increasing mitochondrial biogenesis, and limiting oxidative stress and mitochondrial autophagy. These findings add to our understanding of the mechanism of NSC treatment and shed light on further clinical treatment options.

Dose-response relationship between 15 weeks of running and aerobic fitness: a retrospective analysis based on the fun running program

BACKGROUND

Students' physical fitness, particularly aerobic fitness, has seriously declined during the COVID-19 epidemic. However, in the post-epidemic era, there are few studies on the methods of improving aerobic fitness. Understanding the dose-response relationship between physical activity and aerobic fitness is crucial for developing effective exercise prescriptions.

METHOD

This retrospective study reviewed the Fun Running program at Wannan Medical College in China. We conducted a pre-post study design to analyze the impact of 15 weeks of Fun Running training on aerobic fitness. Middle and long-distance running pace (MLDR-P) was used as the primary indicator of aerobic fitness. A paired sample T-test was used to analyze the differences between the two MLDR-Ps. Pearson's correlation was used to examine the correlation between variables. Multiple linear regression was used to determine the extent to which Fun Running components explain the variance in MLDR-P.

RESULTS

A total of 3244 college students participated in this study. 15 weeks of Fun Running training can significantly improve the MLDR-P in both females (P < 0.001, ES = 0.68) and males (P < 0.001, ES = 0.72). The MLDR-P was significantly correlated with Fun Running (R2 = 0.95, p < 0.05, for females; R2 = 0.96, p < 0.05, for males). The component that had the greatest impact on MLDR-P was pace (β = 1.39, for females; β = 1.09, for males), followed by distance (β = 0.49, for females; β = 0.15, for males), and last frequency (β = -0.03, for all).

CONCLUSION

This study fills the gap in research on the dose-response relationship between running and aerobic fitness among college students in the post-epidemic era. The results show that 15 weeks of Fun Running training can significantly improve aerobic fitness. Examination of the dose-response relationship between Fun Running and MLDR-P provides practitioners with valuable insights into prescribing aerobic fitness training, allowing them to develop more effective training programs. Future research should focus on how to implement a hierarchical Fun Running program effectively.

Low-intensity exercise training increases systolic function of heart and MHCII low cardiac resident macrophages

Physical activities have beneficial effects on cardiovascular health, although the specific mechanisms are largely unknown. Cardiac resident macrophages (cMacs) and the distribution of their subsets are critical regulators for maintaining cardiovascular health and cardiac functions in both steady and inflammatory states. Therefore, we investigated the subsets of cMacs in mice after low-intensity exercise training to elucidate the exercise-induced dynamic changes of cMacs and the benefits of exercise for the heart. The mice were subjected to treadmill running exercise five days per week for five weeks using a low-intensity exercise training protocol. Low-intensity exercise training resulted in a suppression of body weight gain in mice and a significant increase in the ejection fraction, a parameter that represents the systolic function of the heart. Low-intensity exercise training induced the alterations in the transcriptome of the heart, which are associated with muscle contraction and mitochondrial function. Furthermore, low-intensity exercise training did not alter the number of lymphocyte antigen 6 complex, locus C1 (Ly6c)- cMacs but instead remodeled the distributions of Ly6c- cMac subsets. We observed an increase in the percentage of major histocompatibility complex class II (MHCII)low cMacs and a decrease in the percentage of MHCIIhigh cMacs in the heart after low-intensity exercise training. Therefore, the benefits of exercise for cardiovascular fitness might be associated with the redistribution of cMac subsets and the enhancement of the ejection fraction.

Zika virus-induces metabolic alterations in fetal neuronal progenitors that could influence in neurodevelopment during early pregnancy

Cortical development consists of an orchestrated process in which progenitor cells exhibit distinct fate restrictions regulated by time-dependent activation of energetic pathways. Thus, the hijacking of cellular metabolism by Zika virus (ZIKV) to support its replication may contribute to damage in the developing fetal brain. Here, we showed that ZIKV replicates differently in two glycolytically distinct pools of cortical progenitors derived from human induced pluripotent stem cells (hiPSCs), which resemble the metabolic patterns of quiescence (early hi-NPCs) and immature brain cells (late hi-NPCs) in the forebrain. This differential replication alters the transcription of metabolic genes in both pools of cortical progenitors but solely upregulates the glycolytic capacity of early hi-NPCs. Analysis using Imagestream® revealed that, during early stages of ZIKV replication, in early hi-NPCs there is an increase in lipid droplet abundance and size. This stage of ZIKV replication significantly reduced the mitochondrial distribution in both early and late hi-NPCs. During later stages of ZIKV replication, late hi-NPCs show reduced mitochondrial size and abundance. The finding that there are alterations of cellular metabolism during ZIKV infection which are specific to pools of cortical progenitors at different stages of maturation may help to explain the differences in brain damage over each trimester.

The Key Role of Mitochondrial Function in Health and Disease

The role of mitochondrial function in health and disease has become increasingly recognized, particularly in the last two decades. Mitochondrial dysfunction as well as disruptions of cellular bioenergetics have been shown to be ubiquitous in some of the most prevalent diseases in our society, such as type 2 diabetes, cardiovascular disease, metabolic syndrome, cancer, and Alzheimer's disease. However, the etiology and pathogenesis of mitochondrial dysfunction in multiple diseases have yet to be elucidated, making it one of the most significant medical challenges in our history. However, the rapid advances in our knowledge of cellular metabolism coupled with the novel understanding at the molecular and genetic levels show tremendous promise to one day elucidate the mysteries of this ancient organelle in order to treat it therapeutically when needed. Mitochondrial DNA mutations, infections, aging, and a lack of physical activity have been identified to be major players in mitochondrial dysfunction in multiple diseases. This review examines the complexities of mitochondrial function, whose ancient incorporation into eukaryotic cells for energy purposes was key for the survival and creation of new species. Among these complexities, the tightly intertwined bioenergetics derived from the combustion of alimentary substrates and oxygen are necessary for cellular homeostasis, including the production of reactive oxygen species. This review discusses different etiological mechanisms by which mitochondria could become dysregulated, determining the fate of multiple tissues and organs and being a protagonist in the pathogenesis of many non-communicable diseases. Finally, physical activity is a canonical evolutionary characteristic of humans that remains embedded in our genes. The normalization of a lack of physical activity in our modern society has led to the perception that exercise is an "intervention". However, physical activity remains the modus vivendi engrained in our genes and being sedentary has been the real intervention and collateral effect of modern societies. It is well known that a lack of physical activity leads to mitochondrial dysfunction and, hence, it probably becomes a major etiological factor of many non-communicable diseases affecting modern societies. Since physical activity remains the only stimulus we know that can improve and maintain mitochondrial function, a significant emphasis on exercise promotion should be imperative in order to prevent multiple diseases. Finally, in populations with chronic diseases where mitochondrial dysfunction is involved, an individualized exercise prescription should be crucial for the "metabolic rehabilitation" of many patients. From lessons learned from elite athletes (the perfect human machines), it is possible to translate and apply multiple concepts to the betterment of populations with chronic diseases.

MiR-130a-3p regulates FUNDC1-mediated mitophagy by targeting GJA1 in myocardial ischemia/reperfusion injury

Understanding the complex pathogenesis in myocardial ischemia/reperfusion (I/R) injury (IRI) is an urgent problem in clinical trials. Increasing pieces of evidence have suggested that miRNAs are involved in the occurrence and development of heart diseases by regulating mitochondria-related gene expression. Mitochondria have been acknowledged as the key triggers of cardiac I/R injury. However, the potential impact of miR-130a on mitochondria remains unclear in myocardial IRI. Exploring the regulatory mechanism of miR-130a on mitochondria may provide a new target for IRI therapy. In the present study, we found that miR-130a significantly increased in acute myocardial infarction (AMI) patients and myocardial I/R rats. MiR-130a could downregulate the viability of cardiomyocytes and the knockdown of miR-130a could protect the viability of cardiomyocytes under hypoxia-reoxygenation (HR). Over-expression of miR-130a resulted in mitochondrial dysfunction. It was evidenced by decreases in mitochondrial ATP production, mitochondrial membrane potential (MMP), and an increase in reactive oxygen species (ROS) production. However, suppression of miR-130a could protect against mitochondrial damage, show elevation of mitochondrial ATP production rate and MMP, and reduce ROS production. We further explored the effect of miR-130a on the mitochondrial quality control (QMC) system by determining mitochondrial-protein-specific proteases and analyzed mitochondrial morphology by fluorescence imaging and electron microscopy, respectively. It was noted that miR-130a could suppress mitochondrial fusion and FUNDC1-mediated mitophagy to accelerate myocardial IRI. Moreover, we investigated the potential miR-130a targeted mitochondria-related genes to understand the regulatory mechanism of miR-130a in the setting of myocardial IRI. It was revealed that miR-130a targeted GJA1, and GJA1 rescued IRI by enhancing ATP production rate and oxidative phosphorylation, meanwhile protecting cell viability, MMP, and activating mitophagy. In addition, the knockdown of miR-130a significantly activated FUNDC1-mediated mitophagy, while the knockdown of GJA1 reversed the relevant response. Collectively, our findings suggest that miR-130a regulates FUNDC1-mediated mitophagy by targeting GJA1 in myocardial IRI.

The Role of Nrf2 in Relieving Cerebral Ischemia-Reperfusion Injury

Ischemic stroke includes two related pathological damage processes: brain injury caused by primary ischemia and secondary ischemia reperfusion (I/R) injury. I/R injury has become a worldwide health problem. Unfortunately, there is still a lack of satisfactory drugs for ameliorating cerebral I/R damage. Nrf2 is a vital endogenous antioxidant protein, which combines with Keap1 to maintain a dormant state under physiological conditions. When pathological changes such as I/R occurs, Nrf2 dissociates from Keap1 and activates the expression of downstream antioxidant proteins to exert a protective effect. Recent research have shown that the activated Nrf2 not only effectively inhibits oxidative stress, but also performs the ability to repair the function of compromised mitochondria, alleviate endoplasmic reticulum stress, eliminate inflammatory response, reduce blood-brain barrier permeability, inhibit neuronal apoptosis, enhance the neural network remolding, thereby exerting significant protective effects in alleviating the injuries caused by cell oxygen-glucose deprivation, or animal cerebral I/R. However, no definite clinical application report demonstrated the efficacy of Nrf2 activators in the treatment of cerebral I/R. Therefore, further efforts are needed to elaborate the role of Nrf2 activators in the treatment of cerebral I/R. Here, we reviewed the possible mechanisms underlying its potential pharmacological benefits in alleviating cerebral I/R injury, so as to provide a theoretical basis for studying its mechanism and developing Nrf2 activators.

Role of the N6-methyladenosine regulatory factor in reducing the risk of cardiovascular disease: subtype diagnosis following aerobic exercise-assisted weight loss

OBJECTIVES

This study aimed to construct a model based on different N6-methyladenosine (m6A) regulatory factors involved in reducing the risk of the development of cardiovascular diseases under conditions of aerobic exercise.

METHODS

We screened for significantly different expressions of m6A regulators from the GSE66175 dataset. Five candidate m6A regulators were identified using the random forest model to predict aerobic exercise-mediated fat loss and reduction of the risk of cardiovascular disease. A nomogram model was established for analysis, and the consensus clustering method was used to distinguish between the two m6A clusters (clusters A and B). The single-sample gene set-enrichment analysis method was used to assess the abundance of immune cells in the samples related to cardiovascular anomalies. We determined the relationship between the functions of 29 immune cells and m6A clusters.

RESULTS

Twelve significantly and differentially expressed m6A regulators in the control and aerobic exercise groups were screened out, and it was observed that METTL13 correlated positively with the expression levels of the YTH domain containing 1 (YTHDC1), YTH N (6)-methyl adenosine RNA binding protein 1, and leucine-rich pentatricopeptide repeat-containing. The fat mass and obesity-associated gene negatively correlated with YTHDC1 and the fragile X mental retardation 1 protein. The random forest and support vector machine models were used to screen the ELAV-like RNA binding protein 1 (ELAVL1), RNA binding motif protein 15B (RBM15B), insulin-like growth factor binding protein 1 (IGFBP1), Wilms tumor 1-associated protein (WTAP), and zinc finger CCCH-type containing 13 (ZC3H13) genes. Analysis of the line graph model and the results obtained using decision curve analysis revealed the efficiency of the model. Gene ontology enrichment analysis was used to analyze the m6A regulatory gene model, and the results suggested that it was associated with RNA splicing. The results obtained using the Kyoto Encyclopedia of Genes and Genomes enrichment analysis method suggests that the genes were associated with Alzheimer's disease and neurodegeneration pathways associated with multiple diseases. The m6A regulatory gene model was associated with most of the immune cells infiltrating tumors and was also closely related to genes associated with lipid metabolism.

CONCLUSIONS

The m6A regulatory factor plays an important role in reducing the risk of cardiovascular disease under conditions of aerobic exercise-assisted weight loss. It is also associated with the metabolic pathways of low-density lipoprotein, high-density lipoprotein, and triglyceride.