The role of microRNA in nutritional control

d-Allulose Supplementation Prevents Diet-Induced Hepatic Lipid Accumulation via miR-130-Mediated Regulation in C57BL/6 Mice

SCOPE

d-allulose is a low-calorie rare sugar. It has been reported that d-allulose supplementation significantly inhibits diet-induced hepatic fat accumulation. However, the underlying molecular mechanisms remain unclear. This study elucidates the mechanism underlying the suppressive effect of d-allulose on hepatic fat accumulation in terms of miRNA regulation.

METHODS AND RESULTS

Male C57BL/6 mice are divided into three experimental groups-normal diet and distilled water (CC group), high-fat diet (HFD) and distilled water (HC group), and HFD and 5% d-allulose solution (HA group)-and fed the respective diets for 8 weeks. Weight gain is significantly lower in the HA group than that in the HC group, although the caloric intake is the same in both. Histological analysis of liver tissues reveals excessive lipid accumulation in the HC group; this is greatly attenuated in the HA group. Real-time PCR and western blot analyses demonstrate that, compared to the HC group, the HA group exhibits decreased hepatic PPARγ and CD36 expression. Hepatic miR-130 expression levels are higher in the HA group than those in the CC and HC groups.

CONCLUSIONS

These results indicate that miRNA changes associated with PPARγ may underlie the suppression of hepatic lipid accumulation induced by d-allulose intake.

Progress of Noncoding RNA Regulating the Growth and Development of Antler Tissue Research

Antler is the secondary sexual characteristic of deer, which develops on the forehead at puberty. It is the only organ that can be regenerated entirely in mammals. Therefore, it is often used as a research model in the field of organ regeneration and wound repair. Many growth factors and proteins play an active role throughout the developmental process of antler regeneration. With the rapid development of sequencing technology, more and more noncoding RNAs (ncRNAs) have been discovered, and the relationship between ncRNA and antler regeneration has gradually become clear. This paper focuses on the research progress of several ncRNAs (including miRNA and lncRNA) in deer antler tissues, which are helpful to reveal the molecular mechanism of deer antler regeneration at the molecular level.

MicroRNA-340 is involved in ultraviolet B-induced pigmentation by regulating the MITF/TYRP1 axis

Objective

There is growing evidence that ultraviolet B (UVB) irradiation can change the expression profile of microRNAs (miRNAs) in immortalized human epidermal melanocytes (Pig-1). We aimed to investigate the effect of miR-340 on regulating UVB-induced pigmentation.

Methods

Real-time quantitative PCR (qRT-PCR) was used to evaluate the expression of miR-340 in Pig-1 cells. Immunoblotting analysis, qRT-PCR, and luciferase reporter assays were used to detect the potential target of miR-340. The sodium hydroxide dissolution assay was used to assess the effect of miR-340 on changes in melanin content.

Results

Expression of miR-340 was reduced in human Pig-1 cells after UVB irradiation. We found a negative correlation between miR-340 and melanocyte inducing transcription factor (MITF) in Pig-1 cells after UVB irradiation. Knockdown and overexpression of MITF in Pig-1 cells down- and upregulated melanogenesis, respectively. Overexpression of miR-340 inhibited MITF expression, reduced the amount of melanin, and suppressed expression of multiple key molecules involved in the pigment synthesis pathway, whereas knockdown of miR-340 showed the opposite results.

Conclusions

Our results showed that miR-340 inhibited melanogenesis by regulating the downstream molecules of MITF and its signaling pathways, suggested that miRNA-340 may be a new target for the clinical treatment of UVB-induced pigmentation.

Reading between the (Genetic) Lines: How Epigenetics is Unlocking Novel Therapies for Type 1 Diabetes

Type 1 diabetes (T1D) is an autoimmune condition where the body’s immune cells destroy their insulin-producing pancreatic beta cells leading to dysregulated glycaemia. Individuals with T1D control their blood glucose through exogenous insulin replacement therapy, often using multiple daily injections or pumps. However, failure to accurately mimic intrinsic glucose regulation results in glucose fluctuations and long-term complications impacting key organs such as the heart, kidneys, and/or the eyes. It is well established that genetic and environmental factors contribute to the initiation and progression of T1D, but recent studies show that epigenetic modifications are also important. Here, we discuss key epigenetic modifications associated with T1D pathogenesis and discuss how recent research is finding ways to harness epigenetic mechanisms to prevent, reverse, or manage T1D.

Rutin treats myocardial damage caused by pirarubicin via regulating miR-22-5p-regulated RAP1/ERK signaling pathway

Our experiments have previously demonstrated that rutin (RUT) can improve myocardial damage caused by pirarubicin (THP). However, the underlying molecular mechanisms remain uncertain. In this study, we developed an microRNA (miRNA) chip by replicating the rat model of THP-induced myocardial injury and identified miR-22-5p and the RAP1-member of RAS oncogene family/extracellular regulated protein kinases (RAP1/ERK) signaling pathway as an object of study. Also, in vivo experiments demonstrated that THP caused abnormal changes in the electrocardiogram, cardiac function, and histomorphology in rats (P < .01). THP also reduces the expression of miR-22-5p (P < .01) and increases the levels of RAP1/ERK signaling pathway-related proteins (P < .01, P < .05). RUT significantly improved THP-induced myocardial damage (P < .01), increased the expression of miR-22-5p (P < .01), and decreased the levels of RAP1/ERK signaling pathway-related proteins (P < .01, P < .05). In vitro studies confirmed that Rap1a is one of the target genes of miR-22-5p. miR-22-5p overexpression in cardiomyocytes can affect the RAP1/ERK pathway and reduce reactive oxygen species production and cardiomyocyte apoptosis caused by THP (P < .01), which is consistent with the effect of RUT. Our results indicate that RUT treats THP-induced myocardial damage, which may be achieved by upregulating miR-22-5p, causing changes in its target gene Rap1a and the RAP1/ERK pathway.

Circulating microRNA expression profiling in young obese Korean women

BACKGROUND/OBJECTIVES

This study investigates correlations between circulating microRNAs (miRNAs) and obesity-related parameters among young women (aged 20–30 years old) in Korea.

SUBJECTS/METHODS

We analyzed TaqMan low density arrays (TLDAs) of circulating miRNAs in 9 lean (body mass index [BMI] < 25 kg/m²) and 15 obese (BMI > 25 kg/m²) women. We also performed gene ontology (GO) analyses of the biological functions of predicted miRNA target genes, and clustered the results using the database for annotation, visualization and integrated discovery.

RESULTS

The TLDA cards contain 754 human miRNAs; of these, the levels of 8 circulating miRNAs significantly declined (> 2-fold) in obese subjects compared with those in lean subjects, including miR-1227, miR-144-5p, miR-192, miR-320, miR-320b, miR-484, miR-324-3p, and miR-378. Among them, miR-484 and miR-378 displayed the most significant inverse correlations with BMI (miR-484, r = −0.5484, P = 0.0056; miR-378, r = −0.5538, P = 0.0050) and visceral fat content (miR-484, r = −0.6141, P = 0.0014; miR-378, r = −0.6090, P = 0.0017). GO analysis indicated that genes targeted by miR-484 and miR-378 had major roles in carbohydrate and lipid metabolism.

CONCLUSION

Our result showed the differentially expressed circulating miRNAs in obese subjects compared to lean subjects. Although the mechanistic study to reveal the causal role of miRNAs remains, these miRNAs may be novel biomarkers for obesity.

Incidence of MicroR-4513C/T Gene Variability in Coronary Artery Disease - A Case-Control Study

BACKGROUND

Genetic variants in pre-microRNA genes or the 3'UTR of miRNA target genes could influence miRNA-mediated regulation of gene expression and thus contribute to the susceptibility and prognosis of human diseases. Several studies have investigated the association of genetic variants in the seed region of miRNAs with cardiometabolic phenotypes .Therefore the aim of study was to investigate the potential association of miR-4513 rs2168518 C>T gene variability with the risk of developing CAD and its association with different cardiometabolic phenotypes in an Indian cohort to stratify CAD burden in the general population.

METHODS

The study was conducted on 100 clinically confirmed CAD patients and 100 healthy individuals. Genotyping of MicroR-4513 rs2168518C>T gene variability was performed using Amplification refractory mutation system PCR method.

RESULTS

A significant difference was observed in the genotype distribution among CAD cases and healthy controls. The frequencies of three genotypes CC, CT, TT in CAD patient and healthy controls were 5%, 77%, 18%, and 28%, 45% and 27% respectively. A multivariate analysis showed that miR- 4513 rs2168518 polymorphism is associated with an increased susceptibility to CAD in codominant inheritance model for variant CC vs. CT OR 9.58 CI (3.45-26.57), RR 2.3(1.75-3.02), P=0.001. Results also indicate a potential dominant effect of miR-4513 rs2168518 C/T polymorphism on susceptibility of CAD in dominant inheritance model for variant CC vs. (CT+TT) OR 7.38 (2.71-20.07), RR 1.96 (1.56-2.46), P=0.001. In allelic comparison, T allele weakly increased risk of CAD compared to C allele (OR=1.50, 95% CI (1.09-2.26) RR 1.15 (0.94-1.39) P=0.044.

CONCLUSION

It is concluded that CT genotype and T allele of microR-4513 rs2168518 is strongly associated with increased susceptibility to CAD. Furthers studies with larger sample sizes are necessary to confirm this result.

Potential roles of microRNAs in redox state: An update

Oxidative stress is an important underlying cause of many disease processes and may arise due to either increasing free radical generation or decreasing antioxidant defense systems. MicroRNAs (miRs) are 22-nucleotide non-coding RNAs that may regulate many intracellular processes; and, more recently, they have been implicated in the pathways for free radical generation leading to oxidative stress. However, conversely, there is evidence that miRs may have an antioxidant effect, thus miR expression may be critical for the maintenance of the normal redox state and cell homeostasis. This review addresses these discrepant and opposing miR actions on how they may modify and regulate the oxidative balance.

Nonhuman Primates and Translational Research-Cardiovascular Disease

Cardiovascular disease (CVD) is the leading cause of morbidity and mortality in the United States. Human epidemiological studies provide challenges for understanding mechanisms that regulate initiation and progression of CVD due to variation in lifestyle, diet, and other environmental factors. Studies describing metabolic and physiologic aspects of CVD, and those investigating genetic and epigenetic mechanisms influencing CVD initiation and progression, have been conducted in multiple Old World nonhuman primate (NHP) species. Major advantages of NHPs as models for understanding CVD are their genetic, metabolic, and physiologic similarities with humans, and the ability to control diet, environment, and breeding. These NHP species are also genetically and phenotypically heterogeneous, providing opportunities to study gene by environment interactions that are not feasible in inbred animal models. Each Old World NHP species included in this review brings unique strengths as models to better understand human CVD. All develop CVD without genetic manipulation providing multiple models to discover genetic variants that influence CVD risk. In addition, as each of these NHP species age, their age-related comorbidities such as dyslipidemia and diabetes are accelerated proportionally 3 to 4 times faster than in humans.In this review, we discuss current CVD-related research in NHPs focusing on selected aspects of CVD for which nonprimate model organism studies have left gaps in our understanding of human disease. We include studies on current knowledge of genetics, epigenetics, calorie restriction, maternal calorie restriction and offspring health, maternal obesity and offspring health, nonalcoholic steatohepatitis and steatosis, Chagas disease, microbiome, stem cells, and prevention of CVD.

Review: Epigenetics, developmental programming and nutrition in herbivores

Epidemiological studies in humans and animal models (including ruminants and horses) have highlighted the critical role of nutrition on developmental programming. Indeed, it has been demonstrated that the nutritional environment during the periconceptional period and foetal development can altered the postnatal performance of the resultant offspring. This nutritional programming can be exerted by maternal and paternal lineages and can affect offspring beyond the F1 generation. Alterations in epigenetic mechanisms have been proposed as the causative link behind the programming trajectories observed in the offspring. Although a clear cause-effect relationship between epigenetic modifications during early development and later offspring phenotype has not been demonstrated in livestock species, strong associations have been reported for some epigenetic marks (e.g. messenger RNA) that are worth exploring as possible predictors of future offspring phenotype. In this review, we shortly describe the main epigenetic mechanisms studied so far in mammals (i.e. mainly in the mouse) thought to be associated with developmental programming, and discuss the few studies available in mammalian herbivores (e.g. cattle) showing the effect of nutrition on epigenetic marks and the associated phenotype. Clearly, there is a need to develop research on nutritional strategies capable of modulating the epigenetic machinery with positive influence on the phenotype of livestock herbivores. This type of research is needed to alleviate the challenges currently faced by the livestock industry (e.g. impaired fertility of high-yielding dairy cows). This in turn will have a positive influence on animal welfare and productivity of livestock enterprises.

Emerging concepts on the role of epigenetics in the relationships between nutrition and health

Understanding the physiological and metabolic underpinnings that confer individual differences in responses to diet and diet-related chronic disease is essential to advance the field of nutrition. This includes elucidating the differences in gene expression that are mediated through programming of the genome through epigenetic chromatin modifications. Epigenetic landscapes are influenced by age, genetics, toxins and other environmental factors, including dietary exposures and nutritional status. Epigenetic modifications influence transcription and genome stability are established during development with life-long consequences. They can be inherited from one generation to the next. The covalent modifications of chromatin, which include methylation and acetylation, on DNA nucleotide bases, histone proteins and RNA are derived from intermediates of one-carbon metabolism and central metabolism. They influence key physiological processes throughout life, and together with inherited DNA primary sequence, contribute to responsiveness to environmental stresses, diet and risk for age-related chronic disease. Revealing diet-epigenetic relationships has the potential to transform nutrition science by increasing our fundamental understanding of: (i) the role of nutrients in biological systems, (ii) the resilience of living organisms in responding to environmental perturbations, and (iii) the development of dietary patterns that programme physiology for life-long health. Epigenetics may also enable the classification of individuals with chronic disease for specific dietary management and/or for efficacious diet-pharmaceutical combination therapies. These new emerging concepts at the interface of nutrition and epigenetics were discussed, and future research needs identified by leading experts at the 26th Marabou Symposium entitled 'Nutrition, Epigenetics, Genetics: Impact on Health and Disease'. For a compilation of the general discussion at the marabou symposium, click here http://www.marabousymposium.org/.

Evidence for plant-derived xenomiRs based on a large-scale analysis of public small RNA sequencing data from human samples

In recent years, an increasing number of studies have reported the presence of plant miRNAs in human samples, which resulted in a hypothesis asserting the existence of plant-derived exogenous microRNA (xenomiR). However, this hypothesis is not widely accepted in the scientific community due to possible sample contamination and the small sample size with lack of rigorous statistical analysis. This study provides a systematic statistical test that can validate (or invalidate) the plant-derived xenomiR hypothesis by analyzing 388 small RNA sequencing data from human samples in 11 types of body fluids/tissues. A total of 166 types of plant miRNAs were found in at least one human sample, of which 14 plant miRNAs represented more than 80% of the total plant miRNAs abundance in human samples. Plant miRNA profiles were characterized to be tissue-specific in different human samples. Meanwhile, the plant miRNAs identified from microbiome have an insignificant abundance compared to those from humans, while plant miRNA profiles in human samples were significantly different from those in plants, suggesting that sample contamination is an unlikely reason for all the plant miRNAs detected in human samples. This study also provides a set of testable synthetic miRNAs with isotopes that can be detected in situ after being fed to animals.

Do skeletal muscle-secreted factors influence the function of pancreatic β-cells?

Skeletal muscle is an endocrine organ that secretes a variety of compounds including proteins (myokines), metabolites, microRNAs (miRNAs), and exosomes, many of which are regulated by exercise and play important roles in endocrine signaling. Interorgan communication via muscle-secreted factors therefore provides a novel area for investigation and implicates the importance of skeletal muscle in the pathophysiology of metabolic diseases such as type 2 diabetes (T2D). Given that underlying molecular mechanisms of T2D are subject of ongoing research, in light of new evidence it is probable that interorgan cross-talk between skeletal muscle and pancreatic β-cells plays an important part. To date, the number of studies published in this field provide the basis of this review. Specifically, we discuss current experimental evidence in support for a role of skeletal muscle to β-cell cross-talk, paying particular attention to muscle-secreted factors including myokines, metabolites, miRNAs, and factors contained within exosomes that influence the function and/or the survival of β-cells in health and disease. In reviewing this evidence, we provide an update on the list of known muscle-secreted factors that have potential to influence the function and/or survival of β-cells under normal and diabetic conditions. We also report limitations of current cross-talk methods and discuss future directions in this growing field.

The clinical potential of adipogenesis and obesity-related microRNAs

Obesity is a growing health problem commonly associated with numerous metabolic disorders including type 2 diabetes, hypertension, cardiovascular disease, and some forms of cancer. The burden of obesity and associated cardiometabolic diseases are believed to arise through complex interplay between genetics and epigenetics predisposition, nutrition, environment, and lifestyle. However, the molecular basis and the repertoire of obesity-affecting factors are still unknown. Emerging evidence is connecting microRNAs (miRNAs) dysregulation with adipogenesis and obesity. Alteration in miRNAs expression could result in changes in the pattern of genes controlling a range of biological processes including inflammation, lipid metabolism, insulin resistance and adipogenesis. Hence, understanding exact roles of miRNAs as well as the degree of their contribution to the regulation of adipogenesis and fat cell development in obesity would provide new therapeutic targets for the development of novel and effective anti-obesity drugs. The objective of the current review is to: (i) discuss some of the latest development on relevant miRNAs dysregulation mainly in human adipogenesis and obesity, (ii) emphasize the role of circulating miRNAs as new promising therapeutics and attractive potential biomarkers for treating obesity and associated risk factor diseases, (iii) describe how dietary factors may influence obesity through modulation of miRNAs expression, (iv) highlight some of the actual limitations to the promise of miRNAs as novel therapeutics as well as to their translation for the benefit of patients, and finally (v) provide recommendations for future research on miRNA-based therapeutics that could lead to a breakthrough in the treatment of obesity and its associated pathologies.

Expression analysis of selected classes of circulating exosomal miRNAs in soccer players as an indicator of adaptation to physical activity

Recently studies have shown that, depending on the type of training and its duration, the expression levels of selected circulating myomiRNAs (c-miR-27a,b, c-miR-29a,b,c, c-miR-133a) differ and correlate with the physiological indicators of adaptation to physical activity. To analyse the expression of selected classes of miRNAs in soccer players during different periods of their training cycle. The study involved 22 soccer players aged 17-18 years. The multi-stage 20-m shuttle run test was used to estimate VO2 max among the soccer players. Samples serum were collected at baseline (time point I), after one week (time point II), and after 2 months of training (time point III). The analysis of the relative quantification (RQ) level of three exosomal myomiRNAs, c-miRNA-27b, c-miR-29a, and c-miR-133, was performed by quantitative polymerase chain reaction (qPCR) at three time points - before the training, after 1 week of training and after the completion of two months of competition season training. The expression analysis showed low expression levels (according to references) of all evaluated myomiRNAs before the training cycle. Analysis performed after a week of the training cycle and after completion of the entire training cycle showed elevated expression of all tested myomiRNAs. Statistical analysis revealed significant differences between the first and the second time point in soccer players for c-miR-27b and c-miR-29a; between the first and the third time point for c-miR-27b and c-miR-29a; and between the second and the third time point for c-miR-27b. Statistical analysis showed a positive correlation between the levels of c-miR-29a and VO2 max. Two months of training affected the expression of c-miR-27b and miR-29a in soccer players. The increased expression of c-miR-27b and c-miR-29 with training could indicate their probable role in the adaptation process that takes place in the muscular system. Possibly, the expression of c-miR-29a will be found to be involved in cardiorespiratory fitness in future research.

Formidable challenges to the notion of biologically important roles for dietary small RNAs in ingesting mammals

The notion of uptake of active diet-derived small RNAs (sRNAs) in recipient organisms could have significant implications for our understanding of oral therapeutics and nutrition, for the safe use of RNA interference (RNAi) in agricultural biotechnology, and for ecological relationships. Yet, the transfer and subsequent regulation of gene activity by diet-derived sRNAs in ingesting mammals are still heavily debated. Here, we synthesize current information based on multiple independent studies of mammals, invertebrates, and plants. Rigorous assessment of these data emphasize that uptake of active dietary sRNAs is neither a robust nor a prevalent mechanism to maintain steady-state levels in higher organisms. While disagreement still continues regarding whether such transfer may occur in specialized contexts, concerns about technical difficulties and a lack of consensus on appropriate methods have led to questions regarding the reproducibility and biologic significance of some seemingly positive results. For any continuing investigations, concerted efforts should be made to establish a strong mechanistic basis for potential effects of dietary sRNAs and to agree on methodological guidelines for realizing such proof. Such processes would ensure proper interpretation of studies aiming to prove dietary sRNA activity in mammals and inform potential for application in therapeutics and agriculture.

Analysis of extracellular vesicles produced in the biofilm by the dimorphic yeast Pichia fermentans

The yeast Pichia fermentans DISAABA 726 strain (P. fermentans) is a dimorphic yeast that under different environmental conditions may switch from a yeast-like to pseudohyphal morphology. We hypothesize that exosomes-like vesicles (EV) could mediate this rapid modification. EV are membrane-derived vesicles carrying lipids, proteins, mRNAs and microRNAs and have been recognized as important mediators of intercellular communication. Although it has been assumed for a long time that fungi release EV, knowledge of their functions is still limited. In this work we analyze P. fermentans EV production during growth in two different media containing urea (YCU) or methionine (YCM) where yeast-like or pseudohyphal morphology are produced. We developed a procedure to extract EV from the neighboring biofilm which is faster and more efficient as compared to the widely used ultracentrifugation method. Differences in morphology and RNA content of EV suggest that they might have an active role during dimorphic transition as response to the growth conditions. Our findings are coherent with a general state of hypoxic stress of the pseudohyphal cells.

Inflammation Related MicroRNAs Are Modulated in Total Plasma and in Extracellular Vesicles from Rats with Chronic Ingestion of Sucrose

Circulating microRNAs (miRNAs) and the functional implications of miRNAs contained in extracellular vesicles (EVs) have gained attention in the last decade. Little is known about the regulation of the abundance of plasma miRNAs in response to chronic ingestion of carbohydrates. Therefore, we explored the circulating levels of miR-21, miR-146a, miR-155, and miR-223 in rats consuming sucrose in drinking water. Weanling Wistar rats were 25 weeks with 30% sucrose in drinking water, and miRNAs expression was determined in total plasma and in microvesicles, by RT-qPCR with TaqMan probe based assays for miR-21, miR-146a, miR-155, and miR-223, using cel-miR-39 (as spike in control and reference). Endotoxemia was also measured. Sucrose-fed animals showed higher body weight and retroperitoneal adipose tissue as well as higher glucose and triglyceride plasma levels than controls. Plasma endotoxin levels were low and not different among groups. Plasma miR-21 and miR-223 were higher in the sucrose group (p < 0.05), whereas miR-155 tended to be lower (p = 0.0661), and miR-146a did not show significant differences. In the plasma EVs the same trend was found except for miR-146a that showed significantly higher levels (p < 0.05). Overall, our results show that high carbohydrate ingestion modulates circulating miRNAs levels related to an inflammatory response.

Negligible uptake and transfer of diet-derived pollen microRNAs in adult honey bees

The putative transfer and gene regulatory activities of diet-derived miRNAs in ingesting animals are still debated. Importantly, no study to date has fully examined the role of dietary uptake of miRNA in the honey bee, a critical pollinator in both agricultural and natural ecosystems. After controlled pollen feeding experiments in adult honey bees, we observed that midguts demonstrated robust increases in plant miRNAs after pollen ingestion. However, we found no evidence of biologically relevant delivery of these molecules to proximal or distal tissues of recipient honey bees. Our results, therefore, support the premise that pollen miRNAs ingested as part of a typical diet are not robustly transferred across barrier epithelia of adult honey bees under normal conditions. Key future questions include whether other small RNA species in honey bee diets behave similarly and whether more specialized and specific delivery mechanisms exist for more efficient transport, particularly in the context of stressed barrier epithelia.

Circulating MicroRNAs as Potential Biomarkers of Exercise Response

Systematic physical activity increases physical fitness and exercise capacity that lead to the improvement of health status and athletic performance. Considerable effort is devoted to identifying new biomarkers capable of evaluating exercise performance capacity and progress in training, early detection of overtraining, and monitoring health-related adaptation changes. Recent advances in OMICS technologies have opened new opportunities in the detection of genetic, epigenetic and transcriptomic biomarkers. Very promising are mainly small non-coding microRNAs (miRNAs). miRNAs post-transcriptionally regulate gene expression by binding to mRNA and causing its degradation or inhibiting translation. A growing body of evidence suggests that miRNAs affect many processes and play a crucial role not only in cell differentiation, proliferation and apoptosis, but also affect extracellular matrix composition and maintaining processes of homeostasis. A number of studies have shown changes in distribution profiles of circulating miRNAs (c-miRNAs) associated with various diseases and disorders as well as in samples taken under physiological conditions such as pregnancy or physical exercise. This overview aims to summarize the current knowledge related to the response of blood c-miRNAs profiles to different modes of exercise and to highlight their potential application as a novel class of biomarkers of physical performance capacity and training adaptation.

Stress and Protists: No life without stress

We report a summary of the symposium "Stress and Protists: No life without stress", which was held in September 2015 on the VII European Congress of Protistology in partnership with the International Society of Protistologists (Seville, Spain). We present an overview on general comments and concepts on cellular stress which can be also applied to any protist. Generally, various environmental stressors may induce similar cell responses in very different protists. Two main topics are reported in this manuscript: (i) metallic nanoparticles as environmental pollutants and stressors for aquatic protists, and (ii) ultraviolet radiation - induced stress and photoprotective strategies in ciliates. Model protists such as Chlamydomonas reinhardtii and Tetrahymena thermophila were used to assess stress caused by nanoparticles while stress caused by ultraviolet radiation was tested with free living planktonic ciliates as well as with the symbiont-bearing model ciliate Paramecium bursaria. For future studies, we suggest more intensive analyses on protist stress responses to specific environmental abiotic and/or biotic stressors at molecular and genetic levels up to ecological consequences and food web dynamics.