Investigation of Circulating Extracellular Vesicle MicroRNA Following Two Consecutive Bouts of Muscle-Damaging Exercise

Exercise mediates myocardial infarction via non-coding RNAs

Myocardial infarction (MI), a widespread cardiovascular issue, mainly occurs due to blood clot formation in the coronary arteries, which reduces blood flow to the heart muscle and leads to cell death. Incorporating exercise into a lifestyle can significantly benefit recovery and reduce the risk of future cardiac events for MI patients. Non-coding RNAs (ncRNAs) play various roles in the effects of exercise on myocardial infarction (MI). ncRNAs regulate gene expression, influence cardiac remodeling, angiogenesis, inflammation, oxidative stress, apoptosis, cardioprotection, and cardiac electrophysiology. The expression of specific ncRNAs is altered by exercise, leading to beneficial changes in heart structure, function, and recovery after MI. These ncRNAs modulate molecular pathways that contribute to improved cardiac health, including reducing inflammation, enhancing angiogenesis, promoting cell survival, and mitigating oxidative stress. Furthermore, they are involved in regulating changes in cardiac remodeling, such as hypertrophy and fibrosis, and can influence the electrical properties of the heart, thereby decreasing the risk of arrhythmias. Knowledge on MI has entered a new phase, with investigations of ncRNAs in physical exercise yielding invaluable insights into the impact of this therapeutic modality. This review compiled research on ncRNAs in MI, with an emphasis on their applicability to physical activity.

Exploring the Impact of Exercise-Derived Extracellular Vesicles in Cancer Biology

Cancer remains a major challenge in medicine, prompting exploration of innovative therapies. Recent studies suggest that exercise-derived extracellular vesicles (EVs) may offer potential anti-cancer benefits. These small, membrane-bound particles, including exosomes, carry bioactive molecules such as proteins and RNA that mediate intercellular communication. Exercise has been shown to increase EV secretion, influencing physiological processes like tissue repair, inflammation, and metabolism. Notably, preclinical studies have demonstrated that exercise-derived EVs can inhibit tumor growth, reduce metastasis, and enhance treatment response. For instance, in a study using animal models, exercise-derived EVs were shown to suppress tumor proliferation in breast and colon cancers. Another study reported that these EVs reduced metastatic potential by decreasing the migration and invasion of cancer cells. Additionally, exercise-induced EVs have been found to enhance the effectiveness of chemotherapy by sensitizing tumor cells to treatment. This review highlights the emerging role of exercise-derived circulating biomolecules, particularly EVs, in cancer biology. It discusses the mechanisms through which EVs impact cancer progression, the challenges in translating preclinical findings to clinical practice, and future research directions. Although research in this area is still limited, current findings suggest that EVs could play a crucial role in spreading molecules that promote better health in cancer patients. Understanding these EV profiles could lead to future therapies, such as exercise mimetics or targeted drugs, to treat cancer.

Analysis of plasma-derived small extracellular vesicle characteristics and microRNA cargo following exercise-induced skeletal muscle damage in men

Extracellular vesicle (EV) cargo is known to change in response to stimuli such as muscle damage. This study aimed to assess particle size, concentration and microRNA (miR) content within small EV-enriched separations prepared from human blood taken before and after unaccustomed eccentric-biased exercise-induced muscle damage. Nine male volunteers underwent plyometric jumping and downhill running, with blood samples taken at baseline, 2, and 24 h post-exercise. EVs were separated using size exclusion chromatography (SEC) and their characteristics evaluated by nanoparticle tracking. No changes in EV size or concentration were seen following the muscle-damaging exercise. Small RNA sequencing identified 240 miRs to be consistently present within the EVs. RT-qPCR analysis was performed: specifically, for known muscle-enriched/important miRs, including miR-1, -206, -133a, -133b, -31, -208b, -451a, -486 and - 499 and the immune-important miR-21, -146a and - 155. Notably, none of the immune-important miRs within the EVs tested changed in response to the muscle damage. Of the muscle-associated miRs tested, only the levels of miR-31-5p were seen to change with decreased levels at 24 h compared to baseline and 2 h, indicating involvement in the damage response. These findings shed light on the dynamic role of EV miRs in response to exercise-induced muscle damage.

From sweat to hope: The role of exercise-induced extracellular vesicles in cancer prevention and treatment

The benefits of regular physical exercise on cancer prevention, as well as reducing fatigue, treatment side effects and recurrence, and improving quality of life and overall survival of cancer patients, are increasingly recognised. Initial studies showed that the concentration of extracellular vesicles (EVs) increases during physical activity and that EVs carry biologically active cargo. These EVs are released by blood cells, skeletal muscle and other organs involved in exercise, thus suggesting that EVs may mediate tissue crosstalk during exercise. This possibility triggered a great interest in the study of the roles of EVs in systemic adaptation to exercise and in their potential applications in the prevention and treatment of various diseases, including cancer. This review presents studies exploring the concentration and molecular cargo of EVs released during exercise. Furthermore, we discuss putative stimuli that may trigger EV release from various cell types, the biological functions and the impact of exercise-induced EVs on cancer development and progression. Understanding the interplay between exercise, EVs, and cancer biology may offer insights into novel therapeutic strategies and preventive measures for cancer.

The effects of extracellular vesicles and their cargo on metabolism and its adaptation to physical exercise in insulin resistance and type 2 diabetes

Lifestyle modification represents the first-line strategy for the prevention and treatment of type 2 diabetes mellitus (T2DM), which is frequently associated with obesity and characterized by defective pancreatic insulin secretion and/or insulin resistance. Exercise training is an essential component of lifestyle modification and has been shown to ameliorate insulin resistance by reducing body fat mass and by enhancing skeletal muscle mitochondrial biogenesis and insulin-independent glucose uptake. Additionally, exercising stimulates the release of exerkines such as metabolites or cytokines, but also long non-coding RNA, microRNAs, cell-free DNA (cf-DNA), and extracellular vesicles (EVs), which contribute to inter-tissue communication. There is emerging evidence that EV number and content are altered in obesity and T2DM and may be involved in several metabolic processes, specifically either worsening or improving insulin resistance. This review summarizes the current knowledge on the metabolic effects of exercise training and on the potential role of humoral factors and EV as new biomarkers for early diagnosis and tailored treatment of T2DM.

Exercise improves cardiac fibrosis by stimulating the release of endothelial progenitor cell-derived exosomes and upregulating miR-126 expression

Cardiac fibrosis is an important pathological manifestation of various cardiac diseases such as hypertension, coronary heart disease, and cardiomyopathy, and it is also a key link in heart failure. Previous studies have confirmed that exercise can enhance cardiac function and improve cardiac fibrosis, but the molecular target is still unclear. In this review, we introduce the important role of miR-126 in cardiac protection, and find that it can regulate TGF-β/Smad3 signaling pathway, inhibit cardiac fibroblasts transdifferentiation, and reduce the production of collagen fibers. Recent studies have shown that exosomes secreted by cells can play a specific role through intercellular communication through the microRNAs carried by exosomes. Cardiac endothelial progenitor cell-derived exosomes (EPC-Exos) carry miR-126, and exercise training can not only enhance the release of exosomes, but also up-regulate the expression of miR-126. Therefore, through derivation and analysis, it is believed that exercise can inhibit TGF-β/Smad3 signaling pathway by up-regulating the expression of miR-126 in EPC-Exos, thereby weakening the transdifferentiation of cardiac fibroblasts into myofibroblasts. This review summarizes the specific pathways of exercise to improve cardiac fibrosis by regulating exosomes, which provides new ideas for exercise to promote cardiovascular health.

Exploiting the therapeutic potential of contracting skeletal muscle-released extracellular vesicles in cancer: Current insights and future directions

The health benefits of exercise training in a cancer setting are increasingly acknowledged; however, the underlying molecular mechanisms remain poorly understood. It has been suggested that extracellular vesicles (EVs) released from contracting skeletal muscles play a key role in mediating the systemic benefits of exercise by transporting bioactive molecules, including myokines. Nevertheless, skeletal muscle-derived vesicles account for only about 5% of plasma EVs, with the immune cells making the largest contribution. Moreover, it remains unclear whether the contribution of skeletal muscle-derived EVs increases after physical exercise or how muscle contraction modulates the secretory activity of other tissues and thus influences the content and profile of circulating EVs. Furthermore, the destination of EVs after exercise is unknown, and it depends on their molecular composition, particularly adhesion proteins. The cargo of EVs is influenced by the training program, with acute training sessions having a greater impact than chronic adaptations. Indeed, there are numerous questions regarding the role of EVs in mediating the effects of exercise, the clarification of which is critical for tailoring exercise training prescriptions and designing exercise mimetics for patients unable to engage in exercise programs. This review critically analyzes the current knowledge on the effects of exercise on the content and molecular composition of circulating EVs and their impact on cancer progression.

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.

The separation and identification of circulating small extracellular vesicles from endurance-trained, strength-trained and recreationally active men

Small extracellular vesicles (EV) are membrane-encapsulated particles that carry bioactive cargoes, are released by all cell types and are present in all human biofluids. Changes in EV profiles and abundance occur in response to acute exercise, but this study investigated whether individuals with divergent histories of exercise training (recreationally active controls - CON; endurance-trained - END; strength-trained - STR) presented with varied abundances of small EVs in resting samples and whether the abundance of small EVs differed within each group across two measurement days. Participants (n = 38, all male; CON n = 12, END n = 13, STR n = 13) arrived at the lab on two separate occasions in a rested, overnight fasted state, with standardisation of time of day of sampling, recent dietary intake, time since last meal and time since last exercise training session (∼40 h). Whole blood samples were collected and separated into plasma from which small EVs were separated using size exclusion chromatography and identified in accordance with the Minimal Information For Studies of Extracellular Vesicles (MISEV) guidelines. No differences in the abundance of small EVs were observed within or between groups across multiple methods of small EV identification (nanoparticle tracking analysis, flow cytometry, immunoblot of specific EV markers). Targeted metabolomics of the small EV preparations identified 96 metabolites that were associated with the structure and function of small EVs, with no statistically significant differences in concentrations observed across groups. The results of the current study suggest that the abundance and metabolomic profile of small EVs derived from men with divergent histories of exercise training are similar to those in resting blood samples. KEY POINTS: Extracellular vesicles (EV) are membrane-encapsulated particles that are present in circulation and carry bioactive materials as 'cargo'. The abundance and profile of small EVs are responsive to acute exercise, but little is known about the relationship between small EVs and exercise training. This study examined the abundance, and a targeted metabolomic profile, of small EVs separated from the blood of endurance athletes, strength athletes and recreationally active controls at rest (∼40 h after the most recent exercise session) on two separate but identical lab visits. No differences were observed in the abundance or metabolomic profile of small EV preparations between the groups or between the lab visits within each group. Further research should determine whether the bioactive cargoes (e.g. RNA, protein and additional metabolites) carried within EVs are altered in individuals with divergent histories of exercise training or in response to exercise training interventions.

Single vesicle analysis reveals the release of tetraspanin positive extracellular vesicles into circulation with high intensity intermittent exercise

Small extracellular vesicles (sEVs) are released from all cell types and participate in the intercellular exchange of proteins, lipids, metabolites and nucleic acids. Proteomic, flow cytometry and nanoparticle tracking analyses suggest sEVs are released into circulation with exercise. However, interpretation of these data may be influenced by sources of bias introduced by different analytical approaches. Seven healthy participants carried out a high intensity intermittent training (HIIT) cycle protocol consisting of 4 × 30 s at a work-rate corresponding to 200% of individual max power (watts) interspersed by 4.5 min of active recovery. EDTA-treated blood was collected before and immediately after the final effort. Platelet-poor (PPP) and platelet-free (PFP) plasma was derived by one or two centrifugal spins at 2500 g, respectively (15 min, room temperature). Platelets were counted on an automated haemocytometer. Plasma samples were assessed with the Exoview R100 platform, which immobilises sEVs expressing common tetraspanin markers CD9, CD63, CD81 and CD41a on microfluidic chips and with the aid of fluorescence imaging, counts their abundance at a single sEV resolution, importantly, without a pre-isolation step. There was a lower number of platelets in the PFP than PPP, which was associated with a lower number of CD9, CD63 and CD41a positive sEVs. HIIT induced an increase in fluorescence counts in CD9, CD63 and CD81 positive sEVs in both PPP and PFP. These data support the concept that sEVs are released into circulation with exercise. Furthermore, platelet-free plasma is the preferred, representative analyte to study sEV dynamics and phenotype during exercise. KEY POINTS: Small extracellular vesicles (sEV) are nano-sized particles containing protein, metabolites, lipid and RNA that can be transferred from cell to cell. Previous findings implicate that sEVs are released into circulation with exhaustive, aerobic exercise, but since there is no gold standard method to isolate sEVs, these findings may be subject to bias introduced by different approaches. Here, we use a novel method to immobilise and image sEVs, at single-vesicle resolution, to show sEVs are released into circulation with high intensity intermittent exercise. Since platelet depletion of plasma results in a reduction in sEVs, platelet-free plasma is the preferred analyte to examine sEV dynamics and phenotype in the context of exercise.

Converging protective pathways: Exploring the linkage between physical exercise, extracellular vesicles and oxidative stress

Physical Exercise (EXR) has been shown to have numerous beneficial effects on various systems in the human body. It leads to a decrease in the risk of mortality from chronic diseases, such as cardiovascular disease, cancer, metabolic and central nervous system disorders. EXR results in improving cardiovascular fitness, cognitive function, immune activity, endocrine action, and musculoskeletal health. These positive effects make EXR a valuable intervention for promoting overall health and well-being in individuals of all ages. These beneficial effects are partially mediated by the role of the regular EXR in the adaptation to redox homeostasis counteracting the sudden increase of ROS, the hallmark of many chronic diseases. EXR can trigger the release of numerous humoral factors, e.g. protein, microRNA (miRs), and DNA, that can be shuttled as cargo of Extracellular vesicles (EVs). EVs show different cargo modification after oxidative stress stimuli as well as after EXR. In this review, we aim to highlight the main studies on the role of EVs released during EXR and oxidative stress conditions in enhancing the antioxidant enzymes pathway and in the decrease of oxidative stress environment mediated by their cargo.

Fatiguing freestyle swimming modifies miRNA profiles of circulating extracellular vesicles in athletes

Extracellular vesicles (EVs) are secreted by various tissues and cells under normal physiological or pathological conditions. Exercise-induced EVs may be involved in the adaptation of exercise-induced fatigue. The 1500-m freestyle is the longest pool-based swimming event in the Olympic Games, and there is a paucity of information regarding changes in the miRNA profiles of circulating EVs after a single session of fatiguing swimming. In this study, 13 male freestyle swimmers conducted a fatiguing 1500-m freestyle swimming session at the speed of their best previously recorded swimming performance. Fasting venous blood was collected before and after the swimming session for analysis. 70 miRNAs from the circulating EVs were found to be differentially expressed after the fatiguing 1500-m freestyle swimming session, among which 45 and 25 miRNAs were up-regulated and down-regulated, respectively. As for the target genes of five miRNAs (miR-144-3p, miR-145-3p, miR-509-5p, miR-891b, and miR-890) with the largest expression-fold variation, their functional enrichment analysis demonstrated that the target genes were involved in the regulation of long-term potentiation (LTP), vascular endothelial growth factor (VEGF), glutathione metabolism pathway, dopaminergic synapse, signal transmission, and other biological processes. In summary, these findings reveal that a single session of fatiguing swimming modifies the miRNAs profiles of the circulating EVs, especially miR-144-3p, miR-145-3p, miR-509-5p, miR-891b, and miR-890, which clarifies new mechanisms for the adaptation to a single session of fatiguing exercise from the perspective of EV-miRNAs.

The role of exercise parameters on small extracellular vesicles and microRNAs cargo in preventing neurodegenerative diseases

Physical activity (PA), which includes exercise, can reduce the risk of developing various non-communicable diseases, including neurodegenerative diseases (NDs), and mitigate their adverse effects. However, the mechanisms underlying this ability are not yet fully understood. Among several possible mechanisms proposed, such as the stimulation of brain-derived neurotrophic factor (BDNF), endothelial nitric oxide synthase (eNOS), insulin-like growth factor-1 (IGF-1), vascular endothelial growth factor (VEGF), and nerve growth factor (NGF), the possible involvement of particular vesicular structures enclosed in lipid membranes known as extracellular vesicles (EVs) has recently been investigated. These EVs would appear to exert a paracrine and systemic action through their ability to carry various molecules, particularly so-called microRNAs (miRNAs), performing a function as mediators of intercellular communication. Interestingly, EVs and miRNAs are differentially expressed following PA, but evidence on how different exercise parameters may differentially affect EVs and the miRNAs they carry is still scarce. In this review we summarized the current human findings on the effects of PA and different exercise parameters exerted on EVs and their cargo, focusing on miRNAs molecules, and discussing how this may represent one of the biological mechanisms through which exercise contributes to preventing and slowing NDs.

Energetic Stress-Induced Metabolic Regulation by Extracellular Vesicles

Recent studies have demonstrated that extracellular vesicles (EVs) serve powerful and complex functions in metabolic regulation and metabolic-associated disease, although this field of research is still in its infancy. EVs are released into the extracellular space from all cells and carry a wide range of cargo including miRNAs, mRNA, DNA, proteins, and metabolites that have robust signaling effects in receiving cells. EV production is stimulated by all major stress pathways and, as such, has a role in both restoring homeostasis during stress and perpetuating disease. In metabolic regulation, the dominant stress signal is a lack of energy due to either nutrient deficits or damaged mitochondria from nutrient excess. This stress signal is termed "energetic stress," which triggers a robust and evolutionarily conserved response that engages major cellular stress pathways, the ER unfolded protein response, the hypoxia response, the antioxidant response, and autophagy. This article proposes the model that energetic stress is the dominant stimulator of EV release with a focus on metabolically important cells such as hepatocytes, adipocytes, myocytes, and pancreatic β-cells. Furthermore, this article will discuss how the cargo in stress-stimulated EVs regulates metabolism in receiving cells in both beneficial and detrimental ways. © 2023 American Physiological Society. Compr Physiol 13:5051-5068, 2023.

Exercise-derived skeletal myogenic exosomes as mediators of intercellular crosstalk: a major player in health, disease, and exercise

Exosomes are extracellular membrane vesicles that contain biological macromolecules such as RNAs and proteins. It plays an essential role in physiological and pathological processes as carrier of biologically active substances and new mediator of intercellular communication. It has been reported that myokines secreted by the skeletal muscle are wrapped in small vesicles (e.g., exosomes), secreted into the circulation, and then regulate the receptor cells. This review discussed the regulation of microRNAs (miRNAs), proteins, lipids, and other cargoes carried by skeletal muscle-derived exosomes (SkMCs-Exs) on the body and their effects on pathological states, including injury atrophy, aging, and vascular porosis. We also discussed the role of exercise in regulating skeletal muscle-derived exosomes and its physiological significance.

Transplantation of Exercise-Induced Extracellular Vesicles as a Promising Therapeutic Approach in Ischemic Stroke

Clinical evidence affirms physical exercise is effective in preventive and rehabilitation approaches for ischemic stroke. This sustainable efficacy is independent of cardiovascular risk factors and associates substantial reprogramming in circulating extracellular vesicles (EVs). The intricate journey of pluripotent exercise-induced EVs from parental cells to the whole-body and infiltration to cerebrovascular entity offers several mechanisms to reduce stroke incidence and injury or accelerate the subsequent recovery. This review delineates the potential roles of EVs as prospective effectors of exercise. The candidate miRNA and peptide cargo of exercise-induced EVs with both atheroprotective and neuroprotective characteristics are discussed, along with their presumed targets and pathway interactions. The existing literature provides solid ground to hypothesize that the rich vesicles link exercise to stroke prevention and rehabilitation. However, there are several open questions about the exercise stressors which may optimally regulate EVs kinetic and boost brain mitochondrial adaptations. This review represents a novel perspective on achieving brain fitness against stroke through transplantation of multi-potential EVs generated by multi-parental cells, which is exceptionally reachable in an exercising body.

When should I run-the role of exercise timing in metabolic health

The prevalence of type 2 diabetes is reaching epidemic proportions. First line therapy approaches are lifestyle interventions including exercise. Although a vast amount of studies reports on beneficial effects of exercise on metabolism in humans per se, overall data are contradictory which makes it difficult to optimize interventions. Innovative exercise strategies and its underlying mechanism are needed to elucidate in order to close this therapeutic gap. The skeletal muscle produces and secretes myokines and microRNAs in response to exercise and both are discussed as mechanisms linking exercise and metabolic adaptation. Aspects of chronophysiology such as diurnal variation in insulin sensitivity or exercise as a signal to reset dysregulated peripheral clocks are of growing interest in the context of impaired metabolism. Deep insight of how exercise timing determines metabolic adaptations is required to optimize exercise interventions. This review aims to summarize the current state of research on the interaction between timing of exercise and metabolism in humans, providing insights into proposed mechanistic concepts focusing on myokines and microRNAs. First evidence points to an impact of timing of exercise on health outcome, although data are inconclusive. Underlying mechanisms remain elusive. It is currently unknown if the timed release of mykokines depends on time of day when exercise is performed. microRNAs have been found as an important mediator of processes associated with exercise adaptation. Further research is needed to evaluate their full relevance. In conclusion, it seems to be too early to provide concrete recommendations on timing of exercise to maximize beneficial effects.

Defining the influence of size-exclusion chromatography fraction window and ultrafiltration column choice on extracellular vesicle recovery in a skeletal muscle model

Extracellular vesicles (EVs) have the potential to provide new insights into skeletal muscle (SM) physiology and pathophysiology. However, current isolation protocols often do not eliminate co-isolated components such as lipoproteins and RNA binding proteins that could confound outcomes and hinder downstream clinical translation. In this study, we validated an EV isolation protocol that combined size-exclusion chromatography (SEC) with ultrafiltration (UF) to increase sample throughput, scalability and purity, while providing the very first analysis of the effects of UF column choice and fraction window on EV recovery. C2C12 myotube conditioned medium was pre-concentrated using either Amicon® Ultra 15 or Vivaspin®20 100 KDa UF columns and processed by SEC (IZON, qEV 70 nm). The resulting thirty fractions obtained were individually analysed to identify an optimal fraction window for EV recovery. The EV marker TSG101 could be detected from fractions 5 to 14, while CD9 and Annexin A2 only up to fraction 6. ApoA1+ lipoprotein co-isolates were detected from fraction 6 onwards for both protocols. Strikingly, Amicon and Vivaspin UF concentration protocols led to qualitative and quantitative variations in EV marker profiles and purity. Eliminating lipoprotein co-isolation by reducing the SEC fraction window resulted in a net loss of particles, but increased measures of sample purity and had only a negligible impact on the presence of EV marker proteins. In conclusion, our study developed an effective UF+SEC protocol for the isolation of EVs based on sample purity (fractions 1-5) and total EV abundance (fractions 2-10). We provide evidence to demonstrate that the choice of UF column can affect the composition of the resulting EV preparation and needs to be considered when being applied in EV isolation studies in SM. The resulting protocols will be valuable in isolating highly pure EV preparations for applications in a range of therapeutic and diagnostic studies.

Modulation of the Circulating Extracellular Vesicles in Response to Different Exercise Regimens and Study of Their Inflammatory Effects

Exercise-released extracellular vesicles (EVs) are emerging as a novel class of exerkines that promotes systemic beneficial effects. However, slight differences in the applied exercise protocols in terms of mode, intensity and duration, as well as the need for standardized protocols for EV isolation, make the comparison of the studies in the literature extremely difficult. This work aims to investigate the EV amount and EV-associated miRNAs released in circulation in response to different physical exercise regimens. Healthy individuals were subjected to different exercise protocols: acute aerobic exercise (AAE) and training (AT), acute maximal aerobic exercise (AMAE) and altitude aerobic training (AAT). We found a tendency for total EVs to increase in the sedentary condition compared to trained participants following AAE. Moreover, the cytofluorimetric analysis showed an increase in CD81⁺/SGCA⁺/CD45^- EVs in response to AAE. Although a single bout of moderate/maximal exercise did not impact the total EV number, EV-miRNA levels were affected as a result. In detail, EV-associated miR-206, miR-133b and miR-146a were upregulated following AAE, and this trend appeared intensity-dependent. Finally, THP-1 macrophage treatment with exercise-derived EVs induced an increase of the mRNAs encoding for IL-1β, IL-6 and CD163 using baseline and immediately post-exercise EVs. Still, 1 h post-exercise EVs failed to stimulate a pro-inflammatory program. In conclusion, the reported data provide a better understanding of the release of circulating EVs and their role as mediators of the inflammatory processes associated with exercise.

Effects of a 6-wk Sprint Interval Training Protocol at Different Altitudes on Circulating Extracellular Vesicles

PURPOSE

This study aimed to investigate the modulation of circulating exosome-like extracellular vesicles (ELVs) after 6 wk of sprint interval training (SIT) at sea level and at 2000, 3000, and 4000 m.

METHODS

Thirty trained endurance male athletes (18-35 yr) participated in a 6-wk SIT program (30-s all-out sprint, 4-min 30-s recovery; 4-9 repetitions, 2 sessions per week) at sea level ( n = 8), 2000 m (fraction of inspired oxygen (F io2 ) 0.167, n = 8), 3000 m (F io2 0.145, n = 7), or 4000 m (F io2 0.13, n = 7). Venous blood samples were taken before and after the training period. Plasma ELVs were isolated by size exclusion chromatography, counted by nanoparticle tracking analysis, and characterized according to international standards. Candidate ELV microRNAs (miRNAs) were quantified by real-time polymerase chain reaction.

RESULTS

When the three hypoxic groups were analyzed separately, only very minor differences could be detected in the levels of circulating particles, ELV markers, or miRNA. However, the levels of circulating particles increased (+262%) after training when the three hypoxic groups were pooled, and tended to increase at sea level (+65%), with no difference between these two groups. A trend to an increase was observed for the two ELV markers, TSG101 (+65%) and HSP60 (+441%), at sea level, but not in hypoxia. Training also seemed to decrease the abundance of miR-23a-3p and to increase the abundance of miR-21-5p in hypoxia but not at sea level.

CONCLUSIONS

A 6-wk SIT program tended to increase the basal levels of circulating ELVs when performed at sea level but not in hypoxia. In contrast, ELV miRNA cargo seemed to be modulated in hypoxic conditions only. Further research should explore the potential differences in the origin of ELVs between normoxic and local and systemic hypoxic conditions.

Effects of Exercise on Circulating Extracellular Vesicles in Cardiovascular Disease

The evidence that physical exercise has multiple beneficial effects and is essential to a healthy lifestyle is widely accepted for a long-time. The functional and psychological changes promoted by exercise improve clinical outcomes and prognosis in several diseases, by decreasing mortality, disease severity, and hospital admissions. Nonetheless, the mechanisms that regulate the release, uptake, and communication of several factors in response to exercise are still not well defined. In the last years, extracellular vesicles have attracted significant interest in the scientific community due to their ability to carry and deliver proteins, lipids, and miRNA to distant organs in the body, promoting a very exciting crosstalk machinery. Moreover, increasing evidence suggests that exercise can modulate the release of those factors within EVs into the circulation, mediating its systemic adaptations.In this chapter, we summarize the effects of acute and chronic exercise on the extracellular vesicle dynamics in healthy subjects and patients with cardiovascular disease. The understanding of the changes in the cargo and kinetics of extracellular vesicles in response to exercise may open new possibilities of research and encourage the development of novel therapies that mimic the effects of exercise.

Extracellular vesicle characteristics and microRNA content in cerebral palsy and typically developed individuals at rest and in response to aerobic exercise

In this study, the properties of circulating extracellular vesicles (EVs) were examined in cerebral palsy (CP) and typically developed (TD) individuals at rest and after aerobic exercise, focusing on the size, concentration, and microRNA cargo of EVs. Nine adult individuals with CP performed a single exercise bout consisting of 45 min of Frame Running, and TD participants completed either 45 min of cycling (n = 10; TD EX) or were enrolled as controls with no exercise (n = 10; TD CON). Blood was drawn before and 30 min after exercise and analyzed for EV concentration, size, and microRNA content. The size of EVs was similar in CP vs. TD, and exercise had no effect. Individuals with CP had an overall lower concentration (∼25%, p < 0.05) of EVs. At baseline, let-7a, let-7b and let-7e were downregulated in individuals with CP compared to TD (p < 0.05), while miR-100 expression was higher, and miR-877 and miR-4433 lower in CP compared to TD after exercise (p < 0.05). Interestingly, miR-486 was upregulated ∼2-fold in the EVs of CP vs. TD both at baseline and after exercise. We then performed an in silico analysis of miR-486 targets and identified the satellite cell stemness factor Pax7 as a target of miR-486. C2C12 myoblasts were cultured with a miR-486 mimetic and RNA-sequencing was performed. Gene enrichment analysis revealed that several genes involved in sarcomerogenesis and extracellular matrix (ECM) were downregulated. Our data suggest that circulating miR-486 transported by EVs is elevated in individuals with CP and that miR-486 alters the transcriptome of myoblasts affecting both ECM- and sarcomerogenesis-related genes, providing a link to the skeletal muscle alterations observed in individuals with CP.

Extracellular vesicles and microRNAs are altered in response to exercise, insulin sensitivity and overweight

Extracellular vesicles induced by exercise have emerged as potential mediators of tissue crosstalk. Extracellular vesicles and their cargo miRNAs have been linked to dysglycemia and obesity in animal models, but their role in humans is unclear.

AIM

The aim of the study was to characterize the miRNA content in plasma extracellular vesicle isolates after acute and long-term exercise and to study associations between extracellular vesicle miRNAs, mRNA expression in skeletal muscle and adipose tissue, and cardiometabolic risk factors.

METHODS

Sedentary men with or without dysglycemia and overweight underwent an acute bicycle test and a 12-week exercise intervention with extensive metabolic phenotyping. Gene expression in m. vastus lateralis and subcutaneous adipose tissue was measured with RNA sequencing. Extracellular vesicles were purified from plasma with membrane affinity columns or size exclusion chromatography.

RESULTS

Extracellular vesicle miRNA profiling revealed a transient increase in the number of miRNAs after acute exercise. We identified miRNAs, such as miR-652-3p, that were associated to insulin sensitivity and adiposity. By performing explorative association analyses, we identified two miRNAs, miR-32-5p and miR-339-3p, that were strongly correlated to an adipose tissue macrophage signature.

CONCLUSION

Numerous miRNAs in plasma extracellular vesicle isolates were increased by exercise, and several miRNAs correlated to insulin sensitivity and adiposity. Our findings warrant future studies to characterize exercise-induced extracellular vesicles and cargo miRNA to clarify where exercise-induced extracellular vesicles originate from, and to determine whether they influence metabolic health or exercise adaptation.

Skeletal muscle releases extracellular vesicles with distinct protein and microRNA signatures that function in the muscle microenvironment

Extracellular vesicles (EVs) contain various regulatory molecules and mediate intercellular communications. Although EVs are secreted from various cell types, including skeletal muscle cells, and are present in the blood, their identity is poorly characterized in vivo, limiting the identification of their origin in the blood. Since skeletal muscle is the largest organ in the body, it could substantially contribute to circulating EVs as their source. However, due to the lack of defined markers that distinguish skeletal muscle-derived EVs (SkM-EVs) from others, whether skeletal muscle releases EVs in vivo and how much SkM-EVs account for plasma EVs remain poorly understood. In this work, we perform quantitative proteomic analyses on EVs released from C2C12 cells and human iPS cell-derived myocytes and identify potential marker proteins that mark SkM-EVs. These markers we identified apply to in vivo tracking of SkM-EVs. The results show that skeletal muscle makes only a subtle contribution to plasma EVs as their source in both control and exercise conditions in mice. On the other hand, we demonstrate that SkM-EVs are concentrated in the skeletal muscle interstitium. Furthermore, we show that interstitium EVs are highly enriched with the muscle-specific miRNAs and repress the expression of the paired box transcription factor Pax7, a master regulator for myogenesis. Taken together, our findings confirm previous studies showing that skeletal muscle cells release exosome-like EVs with specific protein and miRNA profiles in vivo and suggest that SkM-EVs mainly play a role within the muscle microenvironment where they accumulate.

MSC-Derived Small Extracellular Vesicles Attenuate Autoimmune Dacryoadenitis by Promoting M2 Macrophage Polarization and Inducing Tregs via miR-100-5p

Background

Mesenchymal stem cell-derived small extracellular vesicles (MSC-sEVs) have been increasingly proved as promising immunomodulators against some autoimmune disorders. However, the possible effect and the underlying mechanism of MSC-sEVs in autoimmune dry eye have been rarely studied.

Methods

Small extracellular vesicles from human umbilical cord mesenchymal stem cells (hUC-MSC-sEVs) were subconjunctivally injected to rabbit dry eye model, and their preventive or therapeutical effects were assessed by recording the clinical and histological scores. Quantitative real-time PCR (Q-PCR), western blot and flow cytometry were performed to evaluate the immunomodulatory effects of hUC-MSC-sEVs on macrophages and T regulatory cells (Tregs) both in vivo and in vitro, and the in vitro T cell proliferation was detected by Bromodeoxyuridine (BrdU) assay. In addition, high expression of miR-100-5p in hUC-MSC-sEVs was identified by Q-PCR, and the functional role of sEVs-miR-100-5p on macrophages was explored by a series of co-culture experiments using sEVs derived from hUC-MSCs transfected with miR-100-5p inhibitor.

Results

We firstly demonstrated that hUC-MSC-sEVs had the preventive and therapeutical effects on rabbit autoimmune dacryoadenitis, an animal model of Sjögren’s syndrome (SS) dry eye. Further investigation revealed that hUC-MSC-sEVs administration effectively elicited macrophages into an anti-inflammatory M2 phenotype and elevated the proportion of Tregs both in vivo and in vitro, which contributed to reduced inflammation and improved tissue damage. Importantly, hUC-MSC-sEVs-educated macrophages with M2-like phenotype exhibited strong capacity to inhibit CD4+ T cell proliferation and promote Treg generation in vitro. Mechanistically, miR-100-5p was highly enriched in hUC-MSC-sEVs, and knockdown of miR-100-5p in hUC-MSC-sEVs partially blunted the promotion of hUC-MSC-sEVs on M2 macrophage polarization and even attenuated the effect of hUC-MSC-sEVs-educated macrophages on T cell suppression and Treg expansion.

Conclusion

Our data indicated that hUC-MSC-sEVs alleviated autoimmune dacryoadenitis by promoting M2 macrophage polarization and Treg generation possibly through shuttling miR-100-5p. This study sheds new light on the application of MSC-sEVs as a promising therapeutic method for SS dry eye.

Malnutrition and Biomarkers: A Journey through Extracellular Vesicles

Extracellular vesicles (EVs) have been identified as active components in cellular communication, which are easily altered both morphologically and chemically by the cellular environment and metabolic state of the body. Due to this sensitivity to the conditions of the cellular microenvironment, EVs have been found to be associated with disease conditions, including those associated with obesity and undernutrition. The sensitivity that EVs show to changes in the cellular microenvironment could be a reflection of early cellular alterations related to conditions of malnutrition, which could eventually be used in the routine monitoring and control of diseases or complications associated with it. However, little is known about the influence of malnutrition alone; that is, without the influence of additional diseases on the heterogeneity and specific content of EVs. To date, studies in “apparently healthy” obese patients show that there are changes in the size, quantity, and content of EVs, as well as correlations with some metabolic parameters (glucose, insulin, and serum lipids) in comparison with non-obese individuals. In light of these changes, a direct participation of EVs in the development of metabolic and cardiovascular complications in obese subjects is thought to exist. However, the mechanisms through which this process might occur are not yet fully understood. The evidence on EVs in conditions of undernutrition is limited, but it suggests that EVs play a role in the maintenance of homeostasis and muscle repair. A better understanding of how EVs participate in or promote cellular signaling in malnutrition conditions could help in the development of new strategies to treat them and their comorbidities.

Exercise-Induced Extracellular Vesicles Delay the Progression of Prostate Cancer

Increasing evidence suggests that regular physical exercise not only reduces the risk of cancer but also improves functional capacity, treatment efficacy and disease outcome in cancer patients. At least partially, these effects are mediated by the secretome of the tissues responding to exercise. The secreted molecules can be released in a carrier-free form or enclosed into extracellular vesicles (EVs). Several recent studies have shown that EVs are actively released into circulation during physical exercise. Here, we for the first time investigated the effects of exercise-induced EVs on the progression of cancer in an F344 rat model of metastatic prostate cancer. Although we did not observe a consistent increase in the circulating EV levels, RNA sequencing analysis demonstrated substantial changes in the RNA content of EVs collected before and immediately after forced wheel running exercise as well as differences between EVs from runners at resting state and sedentary rats. The major RNA biotype in EVs was mRNA, followed by miRNA and rRNA. Molecular functions of differentially expressed RNAs reflected various physiological processes including protein folding, metabolism and regulation of immune responses triggered by the exercise in the parental cells. Intravenous administration of exercise-induced EVs into F344 rats with orthotopically injected syngeneic prostate cancer cells PLS10, demonstrated reduction of the primary tumor volume by 35% and possibly—attenuation of lung metastases. Hence, our data provide the first evidence that exercise-induced EVs may modulate tumor physiology and delay the progression of cancer.

Effects of an acute exercise bout in hypoxia on extracellular vesicle release in healthy and prediabetic subjects

PURPOSE

To investigate exosome-like vesicle (ELV) plasma concentrations and markers of multivesicular body (MVB) biogenesis in skeletal muscle in response to acute exercise.

METHODS

Seventeen healthy (BMI: 23.5±0.5kg·m^-2) and fifteen prediabetic (BMI: 27.3±1.2kg·m^-2) men were randomly assigned to two groups performing an acute cycling bout in normoxia or hypoxia (FiO₂ 14.0%). Venous blood samples were taken before (T0), during (T30) and after (T60) exercise and biopsies from m. vastus lateralis were collected before and after exercise. Plasma ELVs were isolated by size exclusion chromatography, counted by nanoparticle tracking analysis (NTA), and characterized according to international standards, followed by expression analyses of canonical ELV markers in skeletal muscle.

RESULTS

In the healthy normoxic group, the total number of particles in the plasma increased during exercise from T0 to T30 (+313%) followed by a decrease from T30 to T60 (-53%). In the same group, an increase in TSG101, CD81 and HSP60 protein expression was measured after exercise in plasma ELVs; however, in the prediabetic group, the total number of particles in the plasma was not affected by exercise. The mRNA content of TSG101, ALIX and CD9 were upregulated in skeletal muscle after exercise in normoxia; whereas, CD9 and CD81 were downregulated in hypoxia.

CONCLUSIONS

ELV plasma abundance increased in response to acute aerobic exercise in healthy subjects in normoxia, but not in prediabetic subjects, nor in hypoxia. Skeletal muscle analyses suggested that this tissue did not likely play a major role of the exercise-induced increase in circulating ELVs.

Exercise Training and Circulating Small Extracellular Vesicles: Appraisal of Methodological Approaches and Current Knowledge

In response to acute exercise, an array of metabolites, nucleic acids, and proteins are enriched in circulation. Collectively termed "exercise factors," these molecules represent a topical area of research given their speculated contribution to both acute exercise metabolism and adaptation to exercise training. In addition to acute changes induced by exercise, the resting profile of circulating exercise factors may be altered by exercise training. Many exercise factors are speculated to be transported in circulation as the cargo of extracellular vesicles (EVs), and in particular, a sub-category termed "small EVs." This review describes an overview of exercise factors, small EVs and the effects of exercise, but is specifically focused on a critical appraisal of methodological approaches and current knowledge in the context of changes in the resting profile small EVs induced by exercise training, and the potential bioactivities of preparations of these "exercise-trained" small EVs. Research to date can only be considered preliminary, with interpretation of many studies hindered by limited evidence for the rigorous identification of small EVs, and the conflation of acute and chronic responses to exercise due to sample timing in proximity to exercise. Further research that places a greater emphasis on the rigorous identification of small EVs, and interrogation of potential bioactivity is required to establish more detailed descriptions of the response of small EVs to exercise training, and consequent effects on exercise adaptation.

Preliminary Investigations Into the Effect of Exercise-Induced Muscle Damage on Systemic Extracellular Vesicle Release in Trained Younger and Older Men

Background: Exercise-induced muscle damage (EIMD) results in transient muscle inflammation, strength loss, and muscle soreness and may cause subsequent exercise avoidance. Research has recently proven that skeletal muscle can also release extracellular vesicles (EVs) into the circulation following a bout of exercise. However, EV’s potential role, including as a biomarker, in the response to eccentric resistance exercise stimulus remains unclear.

Methods: Twelve (younger, n=7, 27.0±1.5years and older, n=5, 63.0±1.0years) healthy, physically active males, undertaking moderate, regular physical activity (3–5 times per week) performed a unilateral high intensity eccentric exercise protocol. Venous plasma was collected for assessment of EVs and creatine kinase (CK) prior to EIMD, immediately after EIMD, and 1–72h post-EIMD, and maximal voluntary isometric contraction (MVIC) and delayed onset muscle soreness (DOMS) were assessed at all time points, except 1 and 2h post-EIMD.

Results: A significant effect of both time (p=0.005) and group (p<0.001) was noted for MVIC, with younger participants’ MVIC being higher throughout. Whilst a significant increase was observed in DOMS in the younger group (p=0.014) and in the older group (p=0.034) following EIMD, no significant differences were observed between groups. CK was not different between age groups but was altered following the EIMD (main effect of time p=0.026), with increased CK seen immediately post-, at 1 and 2h post-EIMD. EV count tended to be lower in older participants at rest, relative to younger participants (p=0.056), whilst EV modal size did not differ between younger and older participants pre-EIMD. EIMD did not substantially alter EV modal size or EV count in younger or older participants; however, the alteration in EV concentration (ΔCount) and EV modal size (ΔMode) between post-EIMD and pre-EIMD negatively associated with CK activity. No significant associations were noted between MVIC or DOMS and either ΔCount or ΔMode of EVs at any time point.

Conclusion: These findings suggest that profile of EV release, immediately following exercise, may predict later CK release and play a role in the EIMD response. Exercise-induced EV release profiles may therefore serve as an indicator for subsequent muscle damage.

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

Exercise has been recognized as an effective preventive and therapeutic approach for numerous diseases. This review addresses the potential role of circulating extracellular vesicles (EV) cargo that is modulated by physical activity. EV transport and deliver beneficial molecules to adjacent and distant tissues as a whole-body phenomenon, resulting in a healthier global status. Several candidate EV molecules, especially miRNAs, are summarized here as mediators of the beneficial effects of exercise, using different modalities, frequencies, volumes, and intensities. The following are among the candidate miRNAs: miR-21, miR-146, miR-486, miR-148a-3p, miR-223-3p, miR-142-3p, and miR-191a-5p. We highlight the relationship between EV cargo modifications, their targets and pathway interactions, in clinical outcomes, for example, on cardiovascular or immune diseases. This review brings an innovative perspective providing evidence for an intricate biological basis of the relationship between EV cargo and exercise-induced benefits on several diseases. Moreover, specific changes on circulating EV content might potentially be used as biomarkers of exercise efficacy.

Skeletal Muscle Cell Growth Alters the Lipid Composition of Extracellular Vesicles

We sought to characterize the lipid profile of skeletal muscle cell-derived Extracellular Vesicles (EVs) to determine if a hypertrophic stimulus would affect the lipid composition of C2C12 myotube-derived EVs. Analyses included C2C12 murine myoblasts differentiated into myotubes and treated with Insulin-Like Growth Factor 1 (IGF-1) for 24 h to induce hypertrophic growth. EVs were isolated from cell culture media, quantified using Nanoparticle Tracking Analysis (NTA) and analyzed using Transmission Electron Microscopy (TEM). EVs were homogenized and lipids extracted for quantification by Mass Spectrometry followed by downstream lipid class enrichment and lipid chain analysis. IGF-1 treatment elicited an increase in CD63 and CD81 levels (39% and 21%) compared to the controls (16%), respectively. Analysis revealed that skeletal muscle-derived EVs are enriched in bioactive lipids that are likely selectively incorporated into EVs during hypertrophic growth. IGF-1 treatment of myotubes had a significant impact on the levels of diacylglycerol (DG) and ceramide (Cer) in secreted EVs. Specifically, the proportion of unsaturated DG was two- to three-fold higher in EVs derived from IGF-treated cells, as compared to those from control cells. The levels of saturated DG were unaffected. Selective increases were similarly seen in C16- and C24-Cer but not in other species. Levels of free sphingoid bases tended to decrease, while those of sphingosine-1-phosphate was unaffected. Our results suggest that the lipid composition and biogenesis of skeletal muscle-derived EVs, are specific and highly selective during hypertrophic growth.

Effects of Voluntary Running Wheel Exercise-Induced Extracellular Vesicles on Anxiety

Anxiety disorders are the most frequently diagnosed psychological condition, associated with serious comorbidities including excessive fear and interference with daily life. Drugs for anxiety disorders are typically prescribed but the side effects include weight gain, nausea, and sleepiness. Exercise is an effective treatment for anxiety. Exercise induces the release of extracellular vesicles (EVs) into the circulation, which transmit signals between organs. However, the effects of exercise-induced EVs on anxiety remain poorly understood. Here, we isolated EVs from the sera of mice that were sedentary or that voluntarily exercised. We characterized the changes in the miRNA profile of serum EVs after 4 weeks of voluntary exercise. miRNA sequencing showed that 82 miRNAs (46 of which were positive and 36 negative regulators) changed after exercise. We selected genes affected by at least two miRNAs. Of these, 27.27% were associated with neurotrophin signaling (9.09% with each of central nervous system neuronal development, cerebral cortical cell migration, and peripheral neuronal development). We also analyzed behavioral changes in mice with 3 weeks of restraint stress-induced anxiety after injection of 20 μg amounts of EVs from exercised or sedentary mice into the left cerebral ventricle. We found that exercise-derived EVs reduced anxiety (compared to a control group) in a nest-building test but found no between-group differences in the rotarod or open field tests. Exercise-derived EVs enhanced the expression of neuroactive ligand-receptor interaction genes. Thus, exercise-derived EVs may exhibit anti-anxiety effects and may be of therapeutic utility.

Short-Term High-Intensity Treadmill Exercise Promotes Ceramide-Dependent Extracellular Vesicle Secretion in the Central Nervous System of Mice

Background

A lack of physical exercise, a critical aspect of a healthy lifestyle, contributes to several cerebral diseases, such as cognitive impairment, Parkinson disease (PD), and Alzheimer disease (AD). The purpose of the present study was to evaluate the effect of physical exercise on cerebral disease via released extracellular vesicles (EVs).

Material/Methods

Short-term high-intensity treadmill exercise was applied to assess the effect of physical activity on EVs in the serum and brain tissue. Immunofluorescence staining and western blot analysis were used to analyze biomarkers of EVs, including TSG101, HSC70, and CD63. Nanoparticle tracking analysis (NTA) was used to analyze the size and concentration of EVs.

Results

Short-term high-intensity exercise increased the number of neuronal EVs in the brain. In the peripheral blood serum, the level of HSC70 showed a temporary increase after exercise and quickly returned to the normal level, whereas the levels of CD63 and TSG101 showed no obvious change in response to physical exercise. In brain tissue, the levels of HSC70 and TSG101 increased dramatically after exercise, while the level of CD63 remained unchanged. The concentration of EVs was significantly increased after exercise, while the mean diameter of the EVs showed no significant change. The levels of ceramide were significantly increased after exercise, and quickly returned to normal levels.

Conclusions

These data suggest that the secretion of EVs in the brain and blood is a transitory response to physical exercise and is dependent on ceramide synthesis.

Hypoxic pancreatic stellate cell-derived exosomal mirnas promote proliferation and invasion of pancreatic cancer through the PTEN/AKT pathway

Pancreatic stellate cells (PSCs) are important components of the tumor microenvironment in pancreatic cancer (PC) and contribute to its development and metastasis through mechanisms that remain incompletely characterized. Tumor hypoxia affects the function and behavior of PC and stromal cells, and can alter exosomal content to modify cell-cell communication. The present study explored the effects of exosomal miRNAs produced by hypoxia-preconditioned PSCs on the growth and metastatic potential of PC cells. Subcutaneous xenografts and liver metastasis mouse models revealed increased tumorigenic potential upon co-implantation of PC cells and PSCs as compared to PC cells alone. Screening miRNA profiles of mouse plasma exosomes and cultured PSCs, followed by miRNA overexpression and inhibition assays, enabled us to identify miR-4465 and miR-616-3p as prominent hypoxia-induced, PSC-derived, exosomal miRNAs promoting PC cell proliferation, migration, and invasion. Proteomics analysis of PC cells incubated with exosomes derived from hypoxic PSCs showed significant downregulation of PTEN. Dual-luciferase reporter assays and western blotting showed that both miR-4465 and miR-616-3p target PTEN and activate AKT signaling in PC cells. We conclude that hypoxia upregulates miR-4465 and miR-616-3p expression in PSC-derived exosomes. Following exosome uptake, these miRNAs promote PC progression and metastasis by suppressing the PTEN/AKT pathway.

Extracellular Vesicles and Exosomes: Insights From Exercise Science

The benefits of exercise on health and longevity are well-established, and evidence suggests that these effects are partially driven by a spectrum of bioactive molecules released into circulation during exercise (e.g., exercise factors or 'exerkines'). Recently, extracellular vesicles (EVs), including microvesicles (MVs) and exosomes or exosome-like vesicles (ELVs), were shown to be secreted concomitantly with exerkines. These EVs have therefore been proposed to act as cargo carriers or 'mediators' of intercellular communication. Given these findings, there has been a rapidly growing interest in the role of EVs in the multi-systemic, adaptive response to exercise. This review aims to summarize our current understanding of the effects of exercise on MVs and ELVs, examine their role in the exercise response and long-term adaptations, and highlight the main methodological hurdles related to blood collection, purification, and characterization of ELVs.

Roles of Skeletal Muscle-Derived Exosomes in Organ Metabolic and Immunological Communication

Skeletal muscles secrete various factors, such as proteins/peptides, nucleotides, and metabolites, which are referred to as myokines. Many of these factors are transported into extracellular bodily fluids in a free or protein-bound form. Furthermore, several secretory factors have been shown to be wrapped up by small vesicles, particularly exosomes, secreted into circulation, and subsequently regulate recipient cells. Thus, exosome contents can be recognized as myokines. In recipient cells, proteins, microRNAs, and metabolites in exosomes can regulate the expression and activity of target proteins associated with nutrient metabolism and immune function. The levels of circulating exosomes and their contents are altered in muscle disorders and metabolic-related states, such as metabolic dysfunction, sarcopenia, and physical fitness. Therefore, such circulating factors could mediate various interactions between skeletal muscle and other organs and may be useful as biomarkers reflecting physiological and pathological states associated with muscular function. Here, this review summarizes secretory regulation of muscle-derived exosomes. Their metabolic and immunological roles and the significance of their circulating levels are also discussed.

Considerations for the Analysis of Small Extracellular Vesicles in Physical Exercise

Physical exercise induces acute physiological changes leading to enhanced tissue cross-talk and a liberation of extracellular vesicles (EVs) into the circulation. EVs are cell-derived membranous entities which carry bioactive material, such as proteins and RNA species, and are important mediators of cell-cell-communication. Different types of physical exercise interventions trigger the release of diverse EV subpopulations, which are hypothesized to be involved in physiological adaptation processes leading to health benefits and longevity. Large EVs (“microvesicles” and “microparticles”) are studied frequently in the context of physical exercise using straight forward flow cytometry approaches. However, the analysis of small EVs (sEVs) including exosomes is hampered by the complex composition of blood, confounding the methodology of EV isolation and characterization. This mini review presents a concise overview of the current state of research on sEVs released upon physical exercise (ExerVs), highlighting the technical limits of ExerV analysis. The purity of EV preparations is highly influenced by the co-isolation of non-EV structures in the size range or density of EVs, such as lipoproteins and protein aggregates. Technical constraints associated with EV purification challenge the quantification of distinct ExerV populations, the identification of their cargo, and the investigation of their biological functions. Here, we offer recommendations for the isolation and characterization of ExerVs to minimize the effects of these drawbacks. Technological advances in the ExerV research field will improve understanding of the inter-cellular cross-talk induced by physical exercise leading to health benefits.

Effects of exercise on exosome release and cargo in in vivo and ex vivo models: A systematic review

Exercise-released exosomes have been identified as novel players to mediate cell-to-cell communication in promoting systemic beneficial effects. This review aimed to systematically investigate the effects of exercise on exosome release and cargo, as well as provide an overview of their physiological implications. Among the 436 articles obtained in the database search (WOS, Scopus, and PubMed), 19 articles were included based on eligibility criteria. Results indicate that exercise promotes the release of exosomes without modification of its vesicle size. The literature has primarily shown an exercise-driven increase in exosome markers (Alix, CD63, CD81, and Flot-1), along with other exosome-carried proteins, into circulation. However, exosome isolation, characterization, and phenotyping methodology, as well as timing of sample recovery following exercise can influence the analysis and interpretation of findings. Moreover, a large number of exosome-carried microRNAs (miRNAs), including miR-1, miR-133a, miR-133b, miR-206, and miR-486, in response to exercise are involved in the modulation of proliferation and differentiation of skeletal muscle tissue, although antigen-presenting cells, leukocytes, endothelial cells, and platelets are the main sources of exosome release into the circulation. Collectively, with the physiological implications as evidenced by the ex vivo trials, the release of exercise-promoted exosomes and their cargo could provide the potential therapeutic applications via the role of intercellular communication.

The Protective Effect of Exercise in Neurodegenerative Diseases: The Potential Role of Extracellular Vesicles

Physical activity has systemic effects on the body, affecting almost every organ. It is important not only for general health and wellbeing, but also in the prevention of diseases. The mechanisms behind the therapeutic effects of physical activity are not completely understood; however, studies indicate these benefits are not confined to simply managing energy balance and body weight. They also include systemic factors which are released into the circulation during exercise and which appear to underlie the myriad of benefits exercise can elicit. It was shown that along with a number of classical cytokines, active tissues also engage in inter-tissue communication via extracellular vesicles (EVs), specifically exosomes and other small EVs, which are able to deliver biomolecules to cells and alter their metabolism. Thus, EVs may play a role in the acute and systemic adaptations that take place during and after physical activity, and may be therapeutically useful in the treatment of a range of diseases, including metabolic disorders such as type 2 diabetes and obesity; and the focus of this review, neurological disorders such as Alzheimer's disease.

Synovial Mesenchymal Stem Cell-Derived EV-Packaged miR-31 Downregulates Histone Demethylase KDM2A to Prevent Knee Osteoarthritis

Extracellular vesicles (EVs) derived from mesenchymal stem cells (MSCs) have emerged as important mediators of intercellular communication in response to cartilage damage. In this study, we sought to characterize the inhibitory role of microRNA (miR)-31 encapsulated in synovial MSC (SMSC)-derived EVs in knee osteoarthritis (OA). The expression of miR-31, lysine demethylase 2A (KDM2A), E2F transcription factor 1 (E2F1), and pituitary tumor transforming gene 1 (PTTG1) was validated in cartilage tissues of knee OA patients. Following SMSC-EV extraction and identification, chondrocytes with the miR-31 inhibitor were added with SMSC-EVs, whereupon the effects of miR-31 on proliferation and migration of chondrocytes were assessed. The interaction among miR-31, KDM2A, E2F1, and PTTG1 in chondrocyte activities was probed in vitro, along with an in vivo mouse knee OA model. We identified downregulated miR-31, E2F1, and PTTG1 and upregulated KDM2A in cartilage tissues of knee OA patients. SMSC-EV-packaged miR-31 potentiated chondrocyte proliferation and migration as well as cartilage formation by targeting KDM2A. Mechanistically, KDM2A bound to the transcription factor E2F1 and inhibited its transcriptional activity. Enrichment of E2F1 in the PTTG1 promoter region activated PTTG1 transcription, accelerating chondrocyte proliferation and migration. SMSC-EVs and EVs from miR-31-overexpressed SMSCs alleviated cartilage damage and inflammation in knee joints in vivo. SMSC-EV-encapsulated miR-31 ameliorates knee OA via the KDM2A/E2F1/PTTG1 axis.

Role of Extracellular Vesicles in Substance Abuse and HIV-Related Neurological Pathologies

Extracellular vesicles (EVs) are a broad, heterogeneous class of membranous lipid-bilayer vesicles that facilitate intercellular communication throughout the body. As important carriers of various types of cargo, including proteins, lipids, DNA fragments, and a variety of small noncoding RNAs, including miRNAs, mRNAs, and siRNAs, EVs may play an important role in the development of addiction and other neurological pathologies, particularly those related to HIV. In this review, we summarize the findings of EV studies in the context of methamphetamine (METH), cocaine, nicotine, opioid, and alcohol use disorders, highlighting important EV cargoes that may contribute to addiction. Additionally, as HIV and substance abuse are often comorbid, we discuss the potential role of EVs in the intersection of substance abuse and HIV. Taken together, the studies presented in this comprehensive review shed light on the potential role of EVs in the exacerbation of substance use and HIV. As a subject of growing interest, EVs may continue to provide information about mechanisms and pathogenesis in substance use disorders and CNS pathologies, perhaps allowing for exploration into potential therapeutic options.

The roles of microRNA in redox metabolism and exercise-mediated adaptation

MicroRNAs (miRs) are small regulatory RNA transcripts capable of post-transcriptional silencing of mRNA messages by entering a cellular bimolecular apparatus called RNA-induced silencing complex. miRs are involved in the regulation of cellular processes producing, eliminating or repairing the damage caused by reactive oxygen species, and they are active players in redox homeostasis. Increased mitochondrial biogenesis, function and hypertrophy of skeletal muscle are important adaptive responses to regular exercise. In the present review, we highlight some of the redox-sensitive regulatory roles of miRs.

Emerging roles of extracellular vesicles in the intercellular communication for exercise-induced adaptations

Complex organisms rely heavily on intercellular communication. The rapidly expanding field of extracellular vesicle biology has made it clear that the necessary intercellular communication occurs partly through their paracrine and endocrine actions. Extracellular vesicles are nanoscale lipid membranes (30-2,000 nm in diameter) that shuttle functional biological material between cells. They are released from numerous tissues and are isolated from nearly all biofluids and cell cultures. Although their biogenesis, cell targeting, and functional roles are incompletely understood, they appear to have crucial roles in physiological and disease processes. Their enormous potential to serve as sensitive biomarkers of disease and also new therapeutic interventions for diseases have gained them considerable attention in recent years. Regular physical exercise training confers systemic health benefits and consequently prevents many age-related degenerative diseases. Many of the molecular mechanisms responsible for the salubrious effects of exercise are known, yet a common underlying mechanism potentially responsible for the holistic health benefits of exercise has only recently been explored (i.e., via extracellular vesicle transport of biological material). Here, we provide an overview of extracellular vesicle biology before outlining the current evidence on the capacity for a single bout and chronic exercise to elicit changes in extracellular vesicle content and modulate their molecular cargo (e.g., small RNAs). We highlight areas for future research and emphasize their potential utility as biomarkers and therapeutic strategies of disease and its prevention.

Extracellular vesicular miRNA expression is not a proxy for skeletal muscle miRNA expression in males and females following acute, moderate intensity exercise

Skeletal muscle and extracellular vesicle (EV) miRNA expression increases following acute endurance exercise. However, research to date has only been performed in males. The aim of this study was to describe the expression levels of a subset of miRNAs in EVs following acute exercise and compare it to skeletal muscle miRNA expression. Twelve males (age 22.9 ± 2.6 years, mean ± SD) and eight females (age 23.0 ± 3.4 years) cycled for 60 min at 70% VO2 peak. Muscle biopsies and blood samples were collected at rest, immediately after and 3 hr after exercise. Acute exercise did not significantly alter the expression of miR-1, miR-16, miR-23b and miR-133a/b in EVs in males and females combined. There were no correlations between EV and skeletal muscle miRNA expression in any of the measured species at any time point. Exploratory analysis revealed differential miRNA responses to exercise between males and females. In males, a weak negative correlation was observed between skeletal muscle and EV miR-16 expression immediately following exercise; however, the physiological relevance of this correlation is unknown. Additionally, when compared with values at rest, male skeletal muscle miR-16 expression significantly increased immediately following exercise, whereas miR-133a expression significantly decreased 3 hr post exercise. Our findings suggest that miRNAs isolated from EVs are not a proxy for skeletal muscle miRNA content. Our exploratory data is the first known evidence of sex-specific differences in the miRNA response to an acute bout of endurance exercise, particularly for miRNA species implicated in mitochondrial metabolism and angiogenesis.

Comprehensive Analysis of Non-coding RNA Profiles of Exosome-Like Vesicles From the Protoscoleces and Hydatid Cyst Fluid of Echinococcus granulosus

Cystic echinococcosis is a worldwide chronic zoonotic disease that threatens human health and animal husbandry. Exosome-like vesicles (ELVs) have emerged recently as mediators in the parasite-parasite intercommunication and parasite-host interactions. Exosome-like vesicles from parasites can transfer non-coding RNAs (ncRNAs) into host cells to regulate their gene expression; however, the ncRNAs profiles of the ELVs from Echinococcus granulosus remain unknown. Here, we isolated protoscolece (PSC)-ELVs and hydatid fluid (HF)-ELVs from the culture medium for E. granulosus PSCs in vitro and the HF of fertile sheep cysts, respectively. The microRNA (miRNA), long non-coding RNA (lncRNA), and circular RNA (circRNA) profiles of the two types of ELVs were analyzed using high-throughput sequencing, and their functions were predicted using Gene Ontology enrichment and Kyoto Encyclopedia of Genes and Genomes pathway analysis. In PSC-ELVs and HF-ELVs, 118 and 58 miRNAs were identified, respectively, among which 53 miRNAs were present in both ELVs, whereas 65 and 5 miRNAs were unique to PSC-ELVs and HF-ELVs, respectively; 2,361 and 1,254 lncRNAs were identified in PSC-ELVs and HF-ELVs, respectively, among which 1,004 lncRNAs were present in both ELVs, whereas 1,357 and 250 lncRNAs were unique to PSC-ELVs and HF-ELVs, respectively. Intriguingly, the spilled PSCs from cysts excrete ELVs with higher numbers of and higher expression levels of miRNAs and circRNAs than HF-ELVs. The miRNA sequencing data were validated by quantitative reverse transcription-polymerase chain reaction. Furthermore, the target lncRNAs and mRNAs regulated by the 20 most abundant miRNAs were screened, and a ceRNA regulatory network containing 5 miRNAs, 41 lncRNAs, and 23 mRNAs was constructed, which provided new ideas and the molecular basis for further clarification of the function and mechanism of E. granulosus ELVs ncRNAs in the parasite-host interactions. Egr-miR-125-5p and egr-miR-10a-5p, sharing identical seed sites with host miRNAs, were predicted to mediate inflammatory response, collagen catabolic process, and mitogen-activated protein kinase cascade during parasite infections. In conclusion, for the first time, we identified the ncRNAs profiles in PSC-ELVs and HF-ELVs that might be involved in host immunity and pathogenesis, and enriched the ncRNAs data of E. granulosus. These results provided valuable resources for further analysis of the regulatory potential of ncRNAs, especially miRNAs, in both types of ELVs at the parasite-host interface.

Exosomes as Actively Targeted Nanocarriers for Cancer Therapy

In recent years, it has been found that exosomes can be used as nanocarriers, which can be used in the treatment of tumors by carrying contents. The exosomes are derived from the secretion of the organism's own cells and are characterized by a phospholipid bilayer structure and a small particle size. These characteristics guarantee that the exosomes can carry a wide range of tumor drugs, deliver the drug to the cancer, and reduce or eliminate the tumor drug band. The toxic side effects were significantly eliminated; meanwhile, the therapeutic effects of the drug on the tumor were remarkably improved. This paper reviewed the strategies and drugs presented by different scholars for the treatment of tumors based on the drugs carried by exosomes.

Sedentary and Trained Older Men Have Distinct Circulating Exosomal microRNA Profiles at Baseline and in Response to Acute Exercise

Exercise has multi-systemic benefits and attenuates the physiological impairments associated with aging. Emerging evidence suggests that circulating exosomes mediate some of the beneficial effects of exercise via the transfer of microRNAs between tissues. However, the impact of regular exercise and acute exercise on circulating exosomal microRNAs (exomiRs) in older populations remains unknown. In the present study, we analyzed circulating exomiR expression in endurance-trained elderly men (n = 5) and age-matched sedentary males (n = 5) at baseline (Pre), immediately after a forty minute bout of aerobic exercise on a cycle ergometer (Post), and three hours after this acute exercise (3hPost). Following the isolation and enrichment of exosomes from plasma, exosome-enriched preparations were characterized and exomiR levels were determined by sequencing. The effect of regular exercise on circulating exomiRs was assessed by comparing the baseline expression levels in the trained and sedentary groups. The effect of acute exercise was determined by comparing baseline and post-training expression levels in each group. Regular exercise resulted in significantly increased baseline expression of three exomiRs (miR-486-5p, miR-215-5p, miR-941) and decreased expression of one exomiR (miR-151b). Acute exercise altered circulating exomiR expression in both groups. However, exomiRs regulated by acute exercise in the trained group (7 miRNAs at Post and 8 at 3hPost) were distinct from those in the sedentary group (9 at Post and 4 at 3hPost). Pathway analysis prediction and reported target validation experiments revealed that the majority of exercise-regulated exomiRs are targeting genes that are related to IGF-1 signaling, a pathway involved in exercise-induced muscle and cardiac hypertrophy. The immediately post-acute exercise exomiR signature in the trained group correlates with activation of IGF-1 signaling, whereas in the sedentary group it is associated with inhibition of IGF-1 signaling. While further validation is needed, including measurements of IGF-1/IGF-1 signaling in blood or skeletal muscle, our results suggest that training status may counteract age-related anabolic resistance by modulating circulating exomiR profiles both at baseline and in response to acute exercise.

The mechanisms and treatments for sarcopenia: could exosomes be a perspective research strategy in the future?

The age-related loss of muscle mass and muscle function known as sarcopenia is a primary contributor to the problems faced by the old people. Sarcopenia has been a major public health problem with high prevalence in many countries. The related underlying molecular mechanisms of sarcopenia are not completely understood. This review is focused on the potential mechanisms and current research strategies for sarcopenia with the aim of facilitating the recognition and treatment of age-related sarcopenia. Previous studies suggested that protein synthesis and degradation, autophagy, impaired satellite cell activation, mitochondria dysfunction, and other factors associated with muscle weakness and muscle degeneration may be potential molecular pathophysiology of sarcopenia. Importantly, we also prospectively highlight that exosomes (small vesicles) as carriers can regulate muscle regeneration and protein synthesis according to recent researches. Dietary strategies and exercise represent the interventions that can also alleviate the progression of sarcopenia. At last, building on recent studies pointing to exosomes with the roles in increasing muscle regeneration, mediating the beneficial effects of exercise, and serving as messengers of intercellular communication and as carriers for research strategies of many diseases, we propose that exosomes could be a potential research direction or strategies of sarcopenia in the future.

The role of extracellular vesicles in skeletal muscle and systematic adaptation to exercise

Regular exercise has a central role in human health by reducing the risk of type 2 diabetes, obesity, stroke and cancer. How exercise is able to promote such systemic benefits has remained somewhat of a mystery but has been thought to be in part mediated by the release of myokines, skeletal muscle-specific cytokines, in response to exercise. Recent studies have revealed skeletal muscle can also release extracellular vesicles (EVs) into circulation following a bout of exercise. EVs are small membrane-bound vesicles capable of delivering biomolecules to recipient cells and subsequently altering their metabolism. The notion that EVs may have a role in both skeletal muscle and systemic adaptation to exercise has generated a great deal of excitement within a number of different fields including exercise physiology, neuroscience and metabolism. The purpose of this review is to provide an introduction to EV biology and what is currently known about skeletal muscle EVs and their potential role in the response of muscle and other tissues to exercise.