Circulating extracellular vesicles delivering beneficial cargo as key players in exercise effects

Molecular insights of exercise therapy in disease prevention and treatment

Despite substantial evidence emphasizing the pleiotropic benefits of exercise for the prevention and treatment of various diseases, the underlying biological mechanisms have not been fully elucidated. Several exercise benefits have been attributed to signaling molecules that are released in response to exercise by different tissues such as skeletal muscle, cardiac muscle, adipose, and liver tissue. These signaling molecules, which are collectively termed exerkines, form a heterogenous group of bioactive substances, mediating inter-organ crosstalk as well as structural and functional tissue adaption. Numerous scientific endeavors have focused on identifying and characterizing new biological mediators with such properties. Additionally, some investigations have focused on the molecular targets of exerkines and the cellular signaling cascades that trigger adaption processes. A detailed understanding of the tissue-specific downstream effects of exerkines is crucial to harness the health-related benefits mediated by exercise and improve targeted exercise programs in health and disease. Herein, we review the current in vivo evidence on exerkine-induced signal transduction across multiple target tissues and highlight the preventive and therapeutic value of exerkine signaling in various diseases. By emphasizing different aspects of exerkine research, we provide a comprehensive overview of (i) the molecular underpinnings of exerkine secretion, (ii) the receptor-dependent and receptor-independent signaling cascades mediating tissue adaption, and (iii) the clinical implications of these mechanisms in disease prevention and treatment.

Acute exercise-induced release of innate immune proteins via small extracellular vesicles changes with aerobic fitness and age

AIM

Physical exercise triggers the secretion of small extracellular vesicles (sEVs) into the circulation in humans, enabling signalling crosstalk between tissues. Exercise-derived EVs and their cargo have been proposed to mediate adaptations to exercise; however, our understanding of how exercise-derived EV protein cargo is modulated by factors such as aerobic fitness and age of an individual is currently unknown. Here, we examined the circulating sEV proteome following aerobic exercise in healthy males of different ages and aerobic fitness to understand exercise-induced EV response during the aging process.

METHODS

Twenty-eight healthy men completed a bout of 20-min cycling exercise at 70% estimated VO2peak . Small EVs were isolated from blood samples collected before and immediately after exercise, and then quantified using particle analysis and Western blotting. Small EV proteome was examined using quantitative proteomic analysis.

RESULTS

We identified a significant increase in 13 proteins in small plasma EVs following moderate-to-vigorous intensity exercise. We observed distinct changes in sEV proteome after exercise in young, mature, unfit, and fit individuals, highlighting the impact of aerobic fitness and age on sEV protein secretion. Functional enrichment and pathway analysis identified that the majority of the significantly altered sEV proteins are associated with the innate immune system, including proteins known to be damage-associated molecular patterns (DAMPs).

CONCLUSION

Together, our findings suggest that exercise-evoked acute stress can positively challenge the innate immune system through the release of signalling molecules such as DAMPs in sEVs, proposing a novel EV-based mechanism for moderate-to-vigorous intensity exercise in immune surveillance pathways.

Interaction of the C2C12 myotube contractions and glucose availability on transcriptome and extracellular vesicle microRNAs

Exercise-like electrical pulse stimulation (EL-EPS) of myotubes mimics many key physiological changes induced by in vivo exercise. Besides enabling intracellular research, EL-EPS allows to study secreted factors, including muscle-specific microRNAs (myomiRs) carried in extracellular vesicles (EVs). These factors can participate in contraction-induced intercellular cross talk and may mediate the health benefits of exercise. However, the current knowledge of these responses, especially under variable nutritional conditions, is limited. We investigated the effects of EL-EPS on C2C12 myotube transcriptome in high- and low-glucose conditions by messenger RNA sequencing, while the expression of EV-carried miRNAs was analyzed by small RNA sequencing and RT-qPCR. We show that higher glucose availability augmented contraction-induced transcriptional changes and that the majority of the differentially expressed genes were upregulated. Furthermore, based on the pathway analyses, processes related to contractility and cytokine/inflammatory responses were upregulated. In addition, we report that EL-EPS increased packing of miR-1-3p into EVs independent of glucose availability. Together our findings suggest that in vitro EL-EPS is a usable tool not only to study contraction-induced intracellular mechanisms but also extracellular responses. The distinct transcriptional changes observed under variable nutritional conditions emphasize the importance of careful consideration of media composition in future exercise-mimicking studies.NEW & NOTEWORTHY The present study examined for the first time the effects of exercise-like electrical pulse stimulation administered under distinct nutritional conditions on 1) the transcriptome of the C2C12 myotubes and 2) their media containing extracellular vesicle-carried microRNAs. We report that higher glucose availability augmented transcriptional responses related especially to contractility and cytokine/inflammatory pathways. Agreeing with in vivo studies, we show that the packing of exercise-responsive miR-1-3p was increased in the extracellular vesicles in response to myotube contractions.

Exploring the role of urinary extracellular vesicles in kidney physiology, aging, and disease progression

Extracellular vesicles (EVs), membranous vesicles present in all body fluids, are considered important messengers, carrying their information over long distance and modulating the gene expression profile of recipient cells. EVs collected in urine (uEVs) are mainly originated from the apical part of urogenital tract, following the urine flow. Moreover, bacterial-derived EVs are present within urine and may reflect the composition of microbiota. Consolidated evidence has established the involvement of uEVs in renal physiology, being responsible for glomerular and tubular cross talk and among different tubular segments. uEVs may also be involved in other physiological functions such as modulation of innate immunity, coagulation, or metabolic activities. Furthermore, it has been recently remonstrated that age, sex, endurance excise, and lifestyle may influence uEV composition and release, modifying their cargo. On the other hand, uEVs appear modulators of different urogenital pathological conditions, triggering disease progression. uEVs sustain fibrosis and inflammation processes, both involved in acute and chronic kidney diseases, aging, and stone formation. The molecular signature of uEVs collected from diseased patients can be of interest for understanding kidney physiopathology and for identifying diagnostic and prognostic biomarkers.

Major Depressive Disorder and Gut Microbiota: Role of Physical Exercise

Major depressive disorder (MDD) has a high prevalence and is a major contributor to the global burden of disease. This psychiatric disorder results from a complex interaction between environmental and genetic factors. In recent years, the role of the gut microbiota in brain health has received particular attention, and compelling evidence has shown that patients suffering from depression have gut dysbiosis. Several studies have reported that gut dysbiosis-induced inflammation may cause and/or contribute to the development of depression through dysregulation of the gut-brain axis. Indeed, as a consequence of gut dysbiosis, neuroinflammatory alterations caused by microglial activation together with impairments in neuroplasticity may contribute to the development of depressive symptoms. The modulation of the gut microbiota has been recognized as a potential therapeutic strategy for the management of MMD. In this regard, physical exercise has been shown to positively change microbiota composition and diversity, and this can underlie, at least in part, its antidepressant effects. Given this, the present review will explore the relationship between physical exercise, gut microbiota and depression, with an emphasis on the potential of physical exercise as a non-invasive strategy for modulating the gut microbiota and, through this, regulating the gut-brain axis and alleviating MDD-related symptoms.

Muscle-derived exosomes and exercise in cancer prevention

There are a lot of evidences on the beneficial effects mediated by exercise on the prevention of not communicable diseases (NCDs) including different type of cancer. The production of circulating exerkines transported in exosomes represents a novel pathway activated by exercise. However, the biological mechanisms that could explain the role of exosomes in cancer prevention have been not fully elucidated. The aim of this mini-review is to provide an update on the biological mechanisms bringing the release of muscle-derived exosomes during exercise and cancer prevention.

Steady-state redox status in circulating extracellular vesicles: A proof-of-principle study on the role of fitness level and short-term aerobic training in healthy young males

Considering the role of redox homeostasis in exercise-induced signaling and adaptation, this study focuses on the exercise training-related intercellular communication of redox status mediated by circulating extracellular vesicles (EVs). 19 healthy young males were divided into trained (TG, 7) and untrained (UG, 12) subjects based on their VO_2MAX. The UG subjects were further randomly distributed in experimental (UG_EX, N = 7) and control (UG_CTRL, N = 5) groups. The steady state of plasma EVs in TG and UG_EX have been characterized for total number and size, as well as cargo redox status (antioxidants, transcription factors, HSPs) before, 3 and 24 h after a single bout of aerobic exercise (30', 70% HRM). Plasma EVs from UG_EX and UG_CTRL have been further characterized after 24 h from the last session of a 5-day consecutive aerobic training or no training, respectively. No differences were detected in the EVs' size and distribution at baseline in TG and UG_EX (p>0.05), while the EVs cargo of UG_EX showed a significantly higher concentration of protein carbonyl, Catalase, SOD2, and HSF1 compared to TG (p<0.05). 5 days of consecutive aerobic training in UG_EX did not determine major changes in the steady-state number and size of EVs. The post-training levels of protein carbonyl, HSF1, Catalase, and SOD2 in EVs cargo of UG_EX resulted significantly lower compared with UG_EX before training and UG_CTRL, resembling the steady-state levels in circulating EVs of TG subjects. Altogether, these preliminary data indicate that individual aerobic capacity influences the redox status of circulating EVs, and that short-term aerobic training impacts the steady-state redox status of EVs. Taking this pilot study as a paradigm for physio-pathological stimuli impacting redox homeostasis, our results offer new insights into the utilization of circulating EVs as biomarkers of exercise efficacy and of early impairment of oxidative-stress related diseases.

Extracellular vesicles and insulin-mediated vascular function in metabolic syndrome

Metabolic Syndrome (MetS) raises cardiovascular disease risk. Extracellular vesicles (EVs) have emerged as important mediators of insulin sensitivity, although few studies on vascular function exist in humans. We determined the effect of insulin on EVs in relation to vascular function. Adults with MetS (n = 51, n = 9 M, 54.8 ± 1.0 years, 36.4 ± 0.7 kg/m2 , ATPIII: 3.5 ± 0.1 a.u., VO2 max: 22.1 ± 0.6 ml/kg/min) were enrolled in this cross-sectional study. Peripheral insulin sensitivity (M-value) was determined during a euglycemic clamp (40 mU/m2 /min, 90 mg/dl), and blood was collected for EVs (CD105+, CD45+, CD41+, TX+, and CD31+; spectral flow cytometry), inflammation, insulin, and substrates. Central hemodynamics (applanation tonometry) was determined at 0 and 120 min via aortic waveforms. Pressure myography was used to assess insulin-induced arterial vasodilation from mouse 3rd order mesenteric arteries (100-200 μm in diameter) at 0.2, 2 and 20 nM of insulin with EVs from healthy and MetS adults. Adults with MetS had low peripheral insulin sensitivity (2.6 ± 0.2 mg/kg/min) and high HOMA-IR (4.7 ± 0.4 a.u.) plus Adipose-IR (13.0 ± 1.3 a.u.). Insulin decreased total/particle counts (p < 0.001), CD45+ EVs (p = 0.002), AIx75 (p = 0.005) and Pb (p = 0.04), FFA (p < 0.001), total adiponectin (p = 0.006), ICAM (p = 0.002), and VCAM (p = 0.03). Higher M-value related to lower fasted total EVs (r = -0.40, p = 0.004) while higher Adipose-IR associated with higher fasted EVs (r = 0.42, p = 0.004) independent of VAT. Fasting CD105+ and CD45+ derived total EVs correlated with fasting AIx75 (r = 0.29, p < 0.05) and Pb (r = 0.30, p < 0.05). EVs from MetS participants blunted insulin-induced vasodilation in mesenteric arteries compared with increases from healthy controls across insulin doses (all p < 0.005). These data highlight EVs as potentially novel mediators of vascular insulin sensitivity and disease risk.

Potential involvement of circulating extracellular vesicles and particles on exercise effects in malignancies

Physical activity and exercise have been widely related to prevention, treatment, and control for several non-communicable diseases. In this context, there are innumerous pre-clinical and clinical evidence indicating the potential role of exercise, beyond cancer prevention and survival, improved quality of life, including on psychological components, bone health and cachexia, from cancer survivors is described as well. This mini-review raises the potential role of circulating extracellular and particles vesicles (EVPs) cargo, as exerkines, conducting several positive effects on adjacent and/or distant tissues such as tumor, immune, bone and muscle cells. We highlighted new perspectives about microRNAs into EVPs changes induced by exercise and its benefits on malignancies, since microRNAs can be implicated with intricated physiopathological processes. Potential microRNAs into EVPs were pointed out here as players spreading beneficial effects of exercise, such as miR-150-5p, miR-124, miR-486, and miRNA-320a, which have previous findings on involvement with clinical outcomes and as well as tumor microenvironment, regulating intercellular communication and tumor growth. For example, high-intensity interval aerobic exercise program seems to increase miR-150 contents in circulating EVPs obtained from women with normal weight or overweight. In accordance circulating EVPs miR-150-5p content is correlated with prognosis colorectal cancer, and ectopic expression of miR-150 may reduce cell proliferation, invasion and metastasis. Beyond the involvement of bioactive miRNAs into circulating EVPs and their pathways related to clinical and preclinical findings, this mini review intends to support further studies on EVPs cargo and exercise effects in oncology.

Circulating Extracellular Vesicles Impair Mesenchymal Stromal Cell Differentiation Favoring Adipogenic Rather than Osteogenic Differentiation in Adolescents with Obesity

Excess body weight has been considered beneficial to bone health because of its anabolic effect on bone formation; however, this results in a poor quality bone structure. In this context, we evaluated the involvement of circulating extracellular vesicles in the impairment of the bone phenotype associated with obesity. Circulating extracellular vesicles were collected from the plasma of participants with normal weight, as well as overweight and obese participants, quantified by flow cytometry analysis and used to treat mesenchymal stromal cells and osteoblasts to assess their effect on cell differentiation and activity. Children with obesity had the highest amount of circulating extracellular vesicles compared to controls. The treatment of mesenchymal stromal cells with extracellular vesicles from obese participants led to an adipogenic differentiation in comparison to vesicles from controls. Mature osteoblasts treated with extracellular vesicles from obese participants showed a reduction in differentiation markers in comparison to controls. Children with obesity who regularly performed physical exercise had a lower circulating extracellular vesicle amount in comparison to those with a sedentary lifestyle. This pilot study demonstrates how the high amount of circulating extracellular vesicles in children with obesity affects the bone phenotype and that physical activity can partially rescue this phenotype.

MicroRNAs as the Sentinels of Redox and Hypertrophic Signalling

Oxidative stress and inflammation are associated with skeletal muscle function decline with ageing or disease or inadequate exercise and/or poor diet. Paradoxically, reactive oxygen species and inflammatory cytokines are key for mounting the muscular and systemic adaptive responses to endurance and resistance exercise. Both ageing and lifestyle-related metabolic dysfunction are strongly linked to exercise redox and hypertrophic insensitivity. The adaptive inability and consequent exercise intolerance may discourage people from physical training resulting in a vicious cycle of under-exercising, energy surplus, chronic mitochondrial stress, accelerated functional decline and increased susceptibility to serious diseases. Skeletal muscles are malleable and dynamic organs, rewiring their metabolism depending on the metabolic or mechanical stress resulting in a specific phenotype. Endogenous RNA silencing molecules, microRNAs, are regulators of these metabolic/phenotypic shifts in skeletal muscles. Skeletal muscle microRNA profiles at baseline and in response to exercise have been observed to differ between adult and older people, as well as trained vs. sedentary individuals. Likewise, the circulating microRNA blueprint varies based on age and training status. Therefore, microRNAs emerge as key regulators of metabolic health/capacity and hormetic adaptability. In this narrative review, we summarise the literature exploring the links between microRNAs and skeletal muscle, as well as systemic adaptation to exercise. We expand a mathematical model of microRNA burst during adaptation to exercise through supporting data from the literature. We describe a potential link between the microRNA-dependent regulation of redox-signalling sensitivity and the ability to mount a hypertrophic response to exercise or nutritional cues. We propose a hypothetical model of endurance exercise-induced microRNA "memory cloud" responsible for establishing a landscape conducive to aerobic as well as anabolic adaptation. We suggest that regular aerobic exercise, complimented by a healthy diet, in addition to promoting mitochondrial health and hypertrophic/insulin sensitivity, may also suppress the glycolytic phenotype and mTOR signalling through miRNAs which in turn promote systemic metabolic health.

Targeting miR-21 in spinal cord injuries: a game-changer?

Spinal cord injury (SCI) is a devastating neurological state causing physical disability, psychological stress and financial burden. SCI global rate is estimated between 250,000 and 500,000 individuals every year, of which 60% of victims are young, healthy males between 15 and 35 years. A variety of pathological conditions such as neuroinflammation, mitochondrial dysfunction, apoptosis, glial scar formation, blood-spinal cord barrier disruption, and angiogenesis disruption occur after SCI leading to a limitation in recovery. MicroRNAs (miRs) are endogenous and non-coding RNAs consisting of 22 nucleotides that regulate 60% of all human genes and involve several normal physiological processes and pathological conditions. miR-21 is among the most highly expressed miRs and its expression has been shown to increase one day after SCI and this elevation is sustained up to 28 days after injury. Overexpression of miR-21 exerts many protective effects against SCI by inhibiting neuroinflammation, improving blood-spinal cord barrier function, regulating angiogenesis, and controlling glial scar formation. It also exhibits anti-apoptotic effects in SCI by down-regulating the expression of PTEN, Spry2, and PDCD4. This review provides a novel therapeutic perspective for miR-21 in SCI.

Urinary extracellular vesicle as a potential biomarker of exercise-induced fatigue in young adult males

Purpose

Previous studies have suggested that circulating extracellular vesicles (EVs) arise after high intensity exercise and urine could reflect the plasma proteome. Herein, we investigated the characteristic of urinary EVs from healthy young adult males who had completed a maximal effort exercise test.

Methods

Thirteen healthy men completed a 20 m shuttle run test (20 m SRT). Fresh urine samples were collected at first morning, right after, and 1 h rest after 20 m SRT. Also, blood lactate, heart rate, rating of perceived exertion, and blood pressure were measured before, right after, and 1 h rest after 20 m SRT. Urinary EVs were analyzed using Exoview instrument and microRNAs (miRNAs) sequencing on urinary EVs were performed.

Results

Urinary EVs increased significantly after exercise and returned to baseline value after 1 h of rest. miRNA sequencing on urinary EV revealed alterations in four miRNAs (1 up and 3 down) and nine miRNAs (2 up and 7 down) in pre- vs. post- and post- vs. post-1 h samples, respectively. Lastly, bioinformatic analysis of urinary EV miRNA suggests that predicted target genes could affect PI3K-Akt, mitogen-activated protein kinase, and insulin pathways by exercise.

Conclusions

Exercise to voluntary exhaustion increased the number of EVs in urine. Also, miRNAs in urinary EVs were altered after exercise. These findings could indicate the possibility of using the urinary EVs as a novel biomarker of acute exercise-induced fatigue.