Regulation of PI3-kinase/Akt signaling by muscle-enriched microRNA-486

LncRNA NEAT1 sponges miR-214-3p to promote osteoblast differentiation through regulating the PI3K/AKT/mTOR pathway in aortic valve calcification

Calcific aortic valve disease (CAVD) is the common valvular disease associated with significant morbidity and mortality. Dysregulation of long non-coding RNA (lncRNA) has been implicated in the pathogenesis of CAVD. This study aims to investigate the role of NEAT1 in CAVD pathogenesis. NEAT1, miR-214-3p and mRNA expressions were determined by qRT-PCR. Protein expressions were detected by Western blotting. Mineralized bone matrix formation was assessed by Alizarin Red staining. The osteogenic phenotype was evaluated by the alkaline phosphatase activity assay. Dual-luciferase assays were employed to confirm the binding interactions between NEAT1 and miR-214-3p, miR-214-3p and PTEN. NEAT1 was up-regulated in calcific aortic valves and after osteogenic induction of valve interstitial cells (VICs). NEAT1 could act as a positive regulator of osteogenic differentiation by repressing miR-214-3p and thereby promote expression of osteoblast-specific markers. Mechanistically, we identified PTEN as a direct target of miR-214-3p. PTEN could regulate the PI3K/AKT/mTOR pathway and participate in osteogenic differentiation. Importantly, NEAT1 could directly interact with miR-214-3p and change of miR-214-3p expression could efficiently reverse PTEN expression and osteogenic differentiation induced by NEAT1. Thus, NEAT1 positively regulated PTEN expression and activated autophagy through sponging miR-214-3p, and promoted osteogenic differentiation through the PI3K/AKT/mTOR pathway. In conclusion, we elucidates the vital function of NEAT1 as a miRNA sponge in CAVD pathogenesis, and sheds new light on lncRNA-directed diagnostic and therapeutic strategies for CAVD.

Lymph Node Exosomes Delivery Attenuates Myocardial Ischemia-Reperfusion Injury via Regulating PTEN-PI3K/Akt Pathway Mediated Myocardiocyte Apoptosis

Background

Ischemia/reperfusion (I/R) injury following acute myocardial infarction (AMI) induces myocardial apoptosis. Exosomes from KLF2-overexpressing endothelial cells (KLF2-EXO) dampened the effects of I/R injury. The intra-lymph node drainage pathway provides an alternative method to study the therapeutic effects of exosomes. In this study, we explored the role of intra-lymph node injection of KLF2-EXO in myocardial I/R injury.

Method and Result

Exosomes were isolated from KLF2-overexpressing mouse coronary endothelial cell supernatant via gradient centrifugation. The mice were subjected to ischemia and reperfusion, and an appropriate dosage of KLF2-EXO was administrated via intra-inguinal lymph node injection. KLF2-EXO attenuated I/R injury and alleviated myocardiocyte apoptosis in heart tissue, and immunofluorescence staining indicated KLF2-EXO could be transferred into the heart. MiRNA-sequencing of KLF2-EXO implicated that miRNA-486-5p (miR-486-5p) was a potent candidate mediator that inhibited myocardiocyte apoptosis, and the miR-486-5p antagomir reversed the effect. Further bioinformatics analysis and confirmation experiments revealed that PTEN functions as a downstream target and that the PTEN- PI3K/Akt pathway participates in the regulation of cardiomyocyte apoptosis.

Conclusion

Our data demonstrated that intra-lymph node injection of KLF2-EXO attenuated myocardial I/R injury in mice by delivering miR-486-5p to target PTEN- PI3K/Akt pathway, which restrained myocardiocyte apoptosis. KLF2-EXO may serve as an alternative therapy for myocardial I/R injury.

Correlation Between CAV-1 and PTEN-Mediated Apoptosis in Hyperoxia-Induced Acute Lung Injury

PURPOSE

Respiratory support is essential in the clinical management of critically ill patients; however, prolonged exposure to high concentrations of oxygen can result in hyperoxia-induced acute lung injury (HALI). In this study, we developed a model of hyperoxia exposure utilizing C57BL/6 mice and human bronchial epithelial (BEAS-2B) cells. We employed CAV-1 siRNA transfection and CAV-1 expression plasmid techniques to analyze the effects of hyperoxia on the expression of caveolin-1 (CAV-1), the deletion of the phosphatase and tensin homolog (PTEN) gene on chromosome 10, and the apoptotic markers Bax and Bcl-2. Additionally, we explored the mechanisms by which CAV-1 regulates PTEN-mediated apoptosis in the context of HALI. Our findings aim to provide valuable insights for developing effective preventive and therapeutic strategies to combat this condition.

METHODS

First, we established a hyperoxia-induced acute lung injury (HALI) model in male C57BL/6 mice. Histopathological examination was conducted using hematoxylin-eosin staining to evaluate the pathological changes and the severity of lung tissue damage. Next, we developed an in vitro HALI model utilizing the BEAS-2B cell line. Subsequently, CAV-1 siRNA and CAV-1 expression plasmids were transfected into BEAS-2B cells. We quantified the expression levels of CAV-1, PTEN, Bax, and Bcl-2 using reverse transcription polymerase chain reaction (RT-PCR) and immunoblotting techniques. Additionally, the impact of altered CAV-1 expression on apoptosis in BEAS-2B cells was assessed through flow cytometry.

RESULTS

Exposure to hyperoxia led to pathological alterations in mice's lung tissue, increased the CAV-1, PTEN, and Bax expression levels, and decreased Bcl-2 expression. Initially, there were no notable variances in the expression levels of CAV-1, PTEN, and Bax in the cells. However, as the exposure time to hyperoxia prolonged, there was a significant increase in both mRNA and protein expression levels of CAV-1 and PTEN, while Bcl-2 exhibited a significant decrease. Moreover, CAV-1 knockdown attenuated the expression of PTEN and Bax, and elevated the expression of Bcl-2. However, CAV-1 overexpression showed an opposite result. The expression levels of CAV-1, PTEN, and Bax were positively correlated in mice and cell models, and negatively correlated with those of Bcl-2. Additionally, downregulation of CAV-1 suppressed apoptosis in BEAS-2B cells.

CONCLUSION

Our results indicate that CAV-1 plays a pivotal role in regulating the expression of PTEN and the apoptosis-related factors Bax and Bcl-2 in a hyperoxic environment. This regulatory function of CAV-1 on PTEN and its downstream apoptotic pathways suggests a significant correlation between CAV-1 and PTEN-mediated apoptosis. Consequently, CAV-1 is involved in the development of hyperoxic lung injury (HALI) through the PTEN-mediated apoptotic pathway. These findings offer new insights into the molecular mechanisms underlying the pathogenesis of HALI and underscore the potential therapeutic implications of targeting CAV-1 in the management of this condition.

Dysregulated cholesterol uptake and efflux of bone marrow-derived α-SMA+ macrophages contribute to atherosclerotic plaque formation

Macrophages play differential roles in the pathogenesis of atherosclerosis due to their different phenotypes. Although α-SMA+ macrophages have been found to present in bone marrow and atherosclerotic plaques, their role in atherosclerosis remains unclear. By performing partial carotid ligation (PCL) on monocyte/macrophage lineage-tracked mice, we observed bone marrow-derived α-SMA+ macrophages in the subendothelium and atherosclerotic plaques under disturbed flow conditions. The functional role of α-SMA+ macrophages in atherosclerotic plaque formation was examined using macrophage-specific Acta2 knockout (Acta2MKO) mice generated by crossing Acta2f/f transgenic mice with LysM-Cre mice. The size of the aortic plaques was 77.43% smaller in Acta2MKO mice than in Acta2f/f mice following adeno-associated virus-mutant PCSK9 injection and high-fat diet (HFD) feeding for 12 weeks. A significant reduction in lipid deposition, macrophage infiltration and the α-SMA+ area was observed in the aortic roots of Acta2MKO mice compared with Acta2f/f mice. Mechanistically, using Acta2-overexpressing Raw264.7 cells (Acta2hi cells) and bone marrow-derived macrophages (BMDMs) from Acta2MKO mice (Acta2MKO BMDMs), we showed that macrophage α-SMA increased the expression of the scavenger receptor SR-A, induced Ox-LDL binding and uptake, and reduced the level of the cholesterol transporter ABCA1, potentially via the AKT pathway. Together, our results indicate that bone marrow-derived α-SMA+ macrophages contribute to atherosclerotic plaque formation due to dysregulated cholesterol uptake and efflux, providing potential targets for the prevention and treatment of atherosclerosis.

MicroRNAs in disease States

This review highlights the role of miRNAs in various diseases affecting major organ systems. miRNAs are small, non-coding RNA molecules that regulate numerous genes. Dysregulation of miRNAs is linked to many pathological conditions due to their involvement in gene silencing and cellular pathways. We discuss miRNA expression patterns, their physiological and pathological roles, and how changes in miRNA levels contribute to disease. Notably, miRNAs like miR-499 and miR-21 are implicated in heart failure and atherosclerosis. miRNA dysregulation is also associated with colorectal and gastric cancers, influencing tumorigenesis and chemoresistance. In neurological diseases, miRNAs exhibit diverse profiles that affect neurodevelopment and degeneration. Additionally, miRNAs modulate cell function in reproductive organs, impacting fertility and cancer progression. miRNAs such as miR-192 and miR-204 serve as biomarkers for nephropathy and acute kidney injury. These miRNAs are involved in skeletal muscle diseases, contributing to conditions like osteoporosis and sarcopenia. miRNAs function as oncogenes or tumor suppressors in cancer, highlighting their potential in diagnostics and therapy. Further research is needed to develop miRNA-based diagnostics and treatments.

Circulating miR-29c, miR-195, and miR-486 Are Objective Indicators to Determine the Moderate Intensity of Resistance Exercise

Background and objective Moderate exercise is important for health; however, there are variations among individuals in terms of characterizing moderate intensity and it is difficult to identify. In light of this, the purpose of this study was to identify new objective indicators to determine effective exercise intensity. Methods This study involved both human and animal experiments. After subjecting mice to exercise of effective intensity, microarray analysis of circulating microRNA expression was conducted to identify candidates for objective indicators to determine effective exercise intensity. Then, we assessed if these microRNAs were altered after aerobic or resistance exercises in humans using quantitative real-time PCR. Twelve healthy males were randomly assigned to two groups: the low-intensity exercise group (LI group) and the high-intensity exercise group (HI group) and they underwent four weeks of exercise program. Results Based on microarray analysis, 188 microRNAs were altered after aerobic exercise, and 167 microRNAs were altered after resistance exercise. Combining these findings with the data from some published reports, we selected miR-29c, miR-23b, miR-222, miR-195, miR-126, miR-133a, and miR-486 as the candidates for biomarkers to determine the effective exercise intensity. In the human study, physical performance improved after resistance exercise only in the HI group. Of the microRNAs, miR-29c, miR-195, and miR-486 increased immediately after resistance exercise only in the HI group. Fold change of miR-486 correlated with changes in knee extensor strength (r=0.744, p=0.005). Conclusions Resistance exercise at effective intensity upregulated the expression of miR-29c, miR-195, and miR-486. Hence, these microRNAs may serve as objective indicators to determine the intensity of resistance exercise. Among them, miR-486 may aid in predicting the response to resistance exercise.

Muscle-enriched microRNA-486-mediated regulation of muscular atrophy and exercise

The objectives of this review were to understand the impact of microRNA-486 on myogenesis and muscle atrophy, and the change of microRNA-486 following exercise, and provide valuable information for improving muscle atrophy based on exercise intervention targeting microRNA-486. Muscle-enriched microRNAs (miRNAs), also referred to as myomiRs, control various processes in skeletal muscles, from myogenesis and muscle homeostasis to different responses to environmental stimuli such as exercise. MicroRNA-486 is a miRNA in which a stem-loop sequence is embedded within the ANKYRIN1 (ANK1) locus and is strictly conserved across mammals. MicroRNA-486 is involved in the development of muscle atrophy caused by aging, immobility, prolonged exposure to microgravity, or muscular and neuromuscular disorders. PI3K/AKT signaling is a positive pathway, as it increases muscle mass by increasing protein synthesis and decreasing protein degradation. MicroRNA-486 can activate this pathway by inhibiting phosphatase and tensin homolog (PTEN), it may also indirectly inhibit the HIPPO signaling pathway to promote cell growth. Exercises regulate microRNA-486 expression both in blood and muscle. This review focused on the recent elucidation of sarcopenia regulation by microRNA-486 and its effects on pathological states, including primary muscular disease, secondary muscular disorders, and age-related sarcopenia. Additionally, the role of exercise in regulating skeletal muscle-enriched microRNA-486 was highlighted, along with its physiological significance. Growing evidence indicates that microRNA-486 significantly impacts the development of muscle atrophy. MicroRNA-486 has great potential to become a therapeutic target for improving muscle atrophy through exercise intervention.

Targeting serum response factor (SRF) deactivates ΔFosB and mitigates Levodopa-induced dyskinesia in a mouse model of Parkinson's disease

L-3,4-dihydroxyphenylalanine (L-DOPA) is currently the preferred treatment for Parkinson's Disease (PD) and is considered the gold standard. However, prolonged use of L-DOPA in patients can result in involuntary movements known as Levodopa-induced dyskinesia (LID), which includes uncontrollable dystonia affecting the trunk, limbs, and face. The role of ΔFosB protein, a truncated splice variant of the FosB gene, in LID has been acknowledged, but its underlying mechanism has remained elusive. Here, using a mouse model of Parkinson's disease treated with chronic levodopa we demonstrate that serum response factor (SRF) binds to the FosB promoter, thereby activating FosB expression and levodopa induced-dyskinetic movements. Western blot analysis demonstrates a significant increase in SRF expression in the dyskinetic group compared to the control group. Knocking down SRF significantly reduced abnormal involuntary movements (AIMS) and ΔFosB expression compared to the control. Conversely, overexpression of SRF led to an increase in ΔFosB expression and worsened levodopa-induced dyskinesia. To shed light on the regulatory role of the Akt signaling pathway in this phenomenon, we administered the Akt agonist SC79 to PD mouse models via intraperitoneal injection, followed by L-DOPA administration. The expression of SRF, ΔFosB, and phosphorylated Akt (p-Akt) significantly increased in this group compared to the group receiving normal saline to signify that these happen through Akt signaling pathway. Collectively, our findings identify a promising therapeutic target for addressing levodopa-induced dyskinesia.

MicroRNAs as commonly expressed biomarkers for sarcopenia and frailty: A systematic review

BACKGROUND

Coexistent sarcopenia and frailty is more strongly associated with adverse health outcomes than each condition alone. As the importance of coexistent sarcopenia and frailty increases, exploring their underlying mechanisms is warranted. Recently, noncoding ribonucleic acids (RNAs) have been suggested as potential biomarkers of sarcopenia and frailty. This systematic review aimed to summarize noncoding RNAs commonly expressed in sarcopenia and frailty, and to search the predicted target genes and biological pathways of them.

METHODS

We systematically searched the literatures on PubMed, Embase, Cochrane Library, Web of Science, and Scopus for literature published till November 15, 2023. A total of 7,202 literatures were initially retrieved. After de-duplication, 34 studies (26 sarcopenia-related and 8 frailty-related) were full-text reviewed, and 15 studies (11 sarcopenia-related and 4 frailty-related) were finally included.

RESULTS

miR-29a-3p, miR-29b-3p, and miR-328 were identified as commonly expressed in same direction in sarcopenia and frailty. These microRNAs (miRNAs), identified in the literature search using PubMed, modulate transforming growth factor-β signaling via extracellular matrix components and calcineurin/nuclear factor of activated T cells 3 signaling via sarcoplasmic/endoplasmic reticulum Ca2+ ATPase 2a, which are involved in regulating skeletal muscle fibrosis and the growth of slow-twitch muscle fibers, respectively. miR-155-5p, miR-486, and miR-23a-3p were also commonly expressed in two conditions, although in different or conflicting directions.

CONCLUSION

In this systematic review, we highlight the potential of shared miRNAs that exhibit consistent expression patterns as biomarkers for the early diagnosis and progression assessment of both sarcopenia and frailty.

Investigating the altered expression of miR-486-5p and miR-novel-chr1_40444 in dysglycemia in a South African population

AIMS

This study aims to investigate miR-486-5p and miR-novel-chr1_40444 expressions in dysglycemic individuals. Validating RNA-sequencing findings in a larger sample via reverse transcription qPCR (RT-qPCR), we aim to address global diagnostic and screening limitations, using an African cohort as an example.

MATERIALS AND METHODS

This cross-sectional study involved 1,271 individuals [normoglycemic (n = 974), prediabetic (n = 206), screen-detected type 2 diabetes (n = 91)] from the ongoing Vascular and Metabolic Health (VMH) study in Cape Town, South Africa. Whole blood miRNA expression was assessed using TaqMan-based RT-qPCR, with data normalized to an endogenous control (miR-16-5p).

RESULTS

Significant underexpression was observed in prediabetes vs normoglycemia for miR-486-5p (P = 0.038), whilst both miRNAs demonstrated significant upregulation in screen-detected type 2 diabetes vs normoglycemia (miR-486-5p, P = 0.009; miR-novel-chr1_40444, P < 0.001), and screen-detected type 2 diabetes in comparison with prediabetes (miR-486-5p, P < 0.001; miR-novel-chr1_40444, P < 0.001). Multivariable regression analyses revealed pronounced interrelations between miR-novel-chr1_40444 and screen-detected type 2 diabetes in unadjusted and adjusted models (Model 1: P < 0.001, Model 2: P < 0.001, Model 3: P = 0.030). Moreover, receiver operating characteristic (ROC) curves revealed significantly enhanced diagnostic capabilities for screen-detected type 2 diabetes vs either normoglycemia (AUC = 0.971, P < 0.001), non-diabetes (AUC = 0.959, P < 0.001), or prediabetes (AUC = 0.902, P < 0.001) when combining the miRNAs with 2 h postprandial glucose.

CONCLUSIONS

This study demonstrated the enhanced power of incorporating miRNAs with traditional markers in distinguishing screen-detected type 2 diabetes, warranting further investigations on their unique role in the development of type 2 diabetes.

The Role of Non-Coding RNAs in Regulating Cachexia Muscle Atrophy

Cachexia is a late consequence of various diseases that is characterized by systemic muscle loss, with or without fat loss, leading to significant mortality. Multiple signaling pathways and molecules that increase catabolism, decrease anabolism, and interfere with muscle regeneration are activated. Non-coding RNAs (ncRNAs), such as microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs), play vital roles in cachexia muscle atrophy. This review mainly provides the mechanisms of specific ncRNAs to regulate muscle loss during cachexia and discusses the role of ncRNAs in cachectic biomarkers and novel therapeutic strategies that could offer new insights for clinical practice.

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.

Circulating MicroRNAs as a biomarker signature of perinatal asphyxia

AIM

This study aimed to explore whether microRNAs (miRNAs) could serve as biomarkers of perinatal asphyxia and whether they were correlated with severity of brain magnetic resonance imaging.

METHODS

We prospectively enrolled 26 full-term newborns, including 10 with perinatal asphyxia and 16 healthy controls. Plasma samples were collected at 0-6 h and 7 days of age. Encephalopathy was classified according to modified Sarnat staging. Magnetic resonance imaging was performed in surviving infants within 30 days of birth, and a score was established. We used next-generation sequencing to explore differentially expressed miRNAs, which were then further validated using quantitative reverse transcription real-time polymerase chain reaction (RT-PCR).

RESULTS

A significantly lower expression of miR-486-5p was found at 0-6 h of age in the asphyxiated newborns compared with the healthy controls (p = 0.005). The area under the receiver operating characteristic curve (AUC) of miR-486-5p at 0-6 h of age to differentiate the perinatal asphyxia group from the healthy control group was 0.831, and the AUC to differentiate newborns eligible for therapeutic hypothermia from others was 0.782. In addition, a lower expression of miR-486-5p at 7 days of age was noted in the asphyxiated newborns with adverse outcomes compared to those with normal outcomes.

CONCLUSION

MiR-486-5p may be a biomarker of perinatal asphyxia in newborns, and further research is warranted to clarify its role.

Expression mechanisms of mir-486-5p and its host gene sANK1 in porcine muscle

BACKGROUND

MiR-486-5p has been identified as a crucial regulator of the PI3K/AKT signalling pathway, which plays a significant role in skeletal muscle development. Its host gene, sANK1, is also essential for skeletal muscle development. However, the understanding of porcine miR-486-5p and sANK1 has been limited.

METHODS AND RESULTS

In this study, PCR analyses revealed a positive correlation between the expression of miR-486-5p and sANK1 in the longissimus dorsi muscle of the Bama mini-pig and Landrace-pig, as well as during myoblast differentiation. Furthermore, the expression of miR-486-5p/sANK1 was higher in the Bama mini-pig compared to the Landrace-pig. There was a total of 18 single nucleotide polymorphisms (SNP) present in the sANK1 promoter region. Among these SNPs, 14 of them resulted in alterations in transcription factor binding sites (TFBs). Additionally, the promoter fluorescence assay demonstrated that the activity of the sANK1 promoter derived from the Bama mini-pig was significantly higher compared to Landrace-pig. It is worth noting that ten regulatory SNPs have the potential to influence the activity of the sANK1 promoter. A nuclear mutation A-G located at position - 401 (relative to the transcription start site) in the Bama mini-pig was identified, which creates a putative TFB motif for MyoD.

CONCLUSIONS

The findings presented in this study offer fundamental molecular knowledge and expression patterns of miR-486-5p/sANK1, which can be valuable for gaining a deeper understanding of the gene's involvement in porcine skeletal muscle development, and meat quality.

Myogenic microRNAs as Therapeutic Targets for Skeletal Muscle Mass Wasting in Breast Cancer Models

Breast cancer is the type of cancer with the highest prevalence in women worldwide. Skeletal muscle atrophy is an important prognostic factor in women diagnosed with breast cancer. This atrophy stems from disrupted skeletal muscle homeostasis, triggered by diminished anabolic signalling and heightened inflammatory conditions, culminating in an upregulation of skeletal muscle proteolysis gene expression. The importance of delving into research on modulators of skeletal muscle atrophy, such as microRNAs (miRNAs), which play a crucial role in regulating cellular signalling pathways involved in skeletal muscle protein synthesis and degradation, has been recognised. This holds true for conditions of homeostasis as well as pathologies like cancer. However, the determination of specific miRNAs that modulate skeletal muscle atrophy in breast cancer conditions has not yet been explored. In this narrative review, we aim to identify miRNAs that could directly or indirectly influence skeletal muscle atrophy in breast cancer models to gain an updated perspective on potential therapeutic targets that could be modulated through resistance exercise training, aiming to mitigate the loss of skeletal muscle mass in breast cancer patients.

Exploring the Role of Extracellular Vesicles in Skeletal Muscle Regeneration

Skeletal muscle regeneration entails a multifaceted process marked by distinct phases, encompassing inflammation, regeneration, and remodeling. The coordination of these phases hinges upon precise intercellular communication orchestrated by diverse cell types and signaling molecules. Recent focus has turned towards extracellular vesicles (EVs), particularly small EVs, as pivotal mediators facilitating intercellular communication throughout muscle regeneration. Notably, injured muscle provokes the release of EVs originating from myofibers and various cell types, including mesenchymal stem cells, satellite cells, and immune cells such as M2 macrophages, which exhibit anti-inflammatory and promyogenic properties. EVs harbor a specific cargo comprising functional proteins, lipids, and nucleic acids, including microRNAs (miRNAs), which intricately regulate gene expression in target cells and activate downstream pathways crucial for skeletal muscle homeostasis and repair. Furthermore, EVs foster angiogenesis, muscle reinnervation, and extracellular matrix remodeling, thereby modulating the tissue microenvironment and promoting effective tissue regeneration. This review consolidates the current understanding on EVs released by cells and damaged tissues throughout various phases of muscle regeneration with a focus on EV cargo, providing new insights on potential therapeutic interventions to mitigate muscle-related pathologies.

Mutant RAS-driven Secretome Causes Skeletal Muscle Defects in Breast Cancer

Cancer-induced skeletal muscle defects differ in severity between individuals with the same cancer type. Cancer subtype-specific genomic aberrations are suggested to mediate these differences, but experimental validation studies are very limited. We utilized three different breast cancer patient-derived xenograft (PDX) models to correlate cancer subtype with skeletal muscle defects. PDXs were derived from brain metastasis of triple-negative breast cancer (TNBC), estrogen receptor-positive/progesterone receptor-positive (ER+/PR+) primary breast cancer from a BRCA2-mutation carrier, and pleural effusion from an ER+/PR- breast cancer. While impaired skeletal muscle function as measured through rotarod performance and reduced levels of circulating and/or skeletal muscle miR-486 were common across all three PDXs, only TNBC-derived PDX activated phospho-p38 in skeletal muscle. To further extend these results, we generated transformed variants of human primary breast epithelial cells from healthy donors using HRASG12V or PIK3CAH1047R mutant oncogenes. Mutations in RAS oncogene or its modulators are found in approximately 37% of metastatic breast cancers, which is often associated with skeletal muscle defects. Although cells transformed with both oncogenes generated adenocarcinomas in NSG mice, only HRASG12V-derived tumors caused skeletal muscle defects affecting rotarod performance, skeletal muscle contraction force, and miR-486, Pax7, pAKT, and p53 levels in skeletal muscle. Circulating levels of the chemokine CXCL1 were elevated only in animals with tumors containing HRASG12V mutation. Because RAS pathway aberrations are found in 19% of cancers, evaluating skeletal muscle defects in the context of genomic aberrations in cancers, particularly RAS pathway mutations, may accelerate development of therapeutic modalities to overcome cancer-induced systemic effects.

SIGNIFICANCE

Mutant RAS- and PIK3CA-driven breast cancers distinctly affect the function of skeletal muscle. Therefore, research and therapeutic targeting of cancer-induced systemic effects need to take aberrant cancer genome into consideration.

Association of circulating hsa-miRNAs with sarcopenia: the SarcoPhAge study

OBJECTIVE

To identify a microRNA signature associated to sarcopenia in community-dwelling older adults form the SarcoPhAge cohort.

METHODS

In a screening phase by next generation sequencing (NGS), we compared the hsa-miRome expression of 18 subjects with sarcopenia (79.6 ± 6.8 years, 9 men) and 19 healthy subjects without sarcopenia (77.1 ± 6 years, 9 men) at baseline. Thereafter, we have selected eight candidate hsa-miRNAs according to the NGS results and after a critical assessment of previous literature. In a validation phase and by real-time qPCR, we then analyzed the expression levels of these 8 hsa-miRNAs at baseline selecting 92 healthy subjects (74.2 ± 10 years) and 92 subjects with sarcopenia (75.3 ± 6.8 years). For both steps, the groups were matched for age and sex.

RESULTS

In the validation phase, serum has-miRNA-133a-3p and has-miRNA-200a-3p were significantly decreased in the group with sarcopenia vs controls [RQ: relative quantification; median (interquartile range)]: -0.16 (-1.26/+0.90) vs +0.34 (-0.73/+1.33) (p < 0.01) and -0.26 (-1.07/+0.68) vs +0.27 (-0.55/+1.10) (p < 0.01) respectively. Has-miRNA-744-5p was decreased and has-miRNA-151a-3p was increased in the group with sarcopenia vs controls, but this barely reached significance: +0.16 (-1.34/+0.79) vs +0.44 (-0.31/+1.00) (p = 0.050) and  +0.35 (-0.22/+0.90) vs  +0.03 (-0.68/+0.75) (p = 0.054).

CONCLUSION

In subjects with sarcopenia, serum hsa-miRNA-133a-3p and hsa-miRNA-200a-3p expression were downregulated, consistent with their potential targets inhibiting muscle cells proliferation and differentiation.

The role of CEMIP in cancers and its transcriptional and post-transcriptional regulation

CEMIP is a protein known for inducing cell migration and binding to hyaluronic acid. Functioning as a hyaluronidase, CEMIP primarily facilitates the breakdown of the extracellular matrix component, hyaluronic acid, thereby regulating various signaling pathways. Recent evidence has highlighted the significant role of CEMIP in different cancers, associating it with diverse pathological states. While identified as a biomarker for several diseases, CEMIP's mechanism in cancer seems distinct. Accumulating data suggests that CEMIP expression is triggered by chemical modifications to itself and other influencing factors. Transcriptionally, chemical alterations to the CEMIP promoter and involvement of transcription factors such as AP-1, HIF, and NF-κB regulate CEMIP levels. Similarly, specific miRNAs have been found to post-transcriptionally regulate CEMIP. This review provides a comprehensive summary of CEMIP's role in various cancers and explores how both transcriptional and post-transcriptional mechanisms control its expression.

Topographic Distribution of miRNAs (miR-30a, miR-223, miR-let-7a, miR-let-7f, miR-451, and miR-486) in the Plasma Extracellular Vesicles

There are many articles on the quantitative analysis of miRNAs contained in a population of EVs of different sizes under various physiological and pathological conditions. For such analysis, it is important to correctly quantify the miRNA contents of EVs. It should be considered that quantification is skewed depending on the isolation protocol, and different miRNAs are degraded by nucleases with different efficiencies. In addition, it is important to consider the contribution of miRNAs coprecipitating with the EVs population, because the amount of miRNAs in the EVs population under study is skewed without appropriate enzymatic treatment. By studying a population of EVs from the blood plasma of healthy donors, we found that the absolute amount of miRNA inside the vesicles is commensurate with the amount of the same type of miRNA adhered to the outside of the EVs. The inside/outside ratio ranged from 1.02 to 2.64 for different investigated miRNAs. According to our results, we propose the hypothesis that high occupancy of miRNAs on the outer surface of EVs influence on the transporting RNA repertoire no less than the inner cargo received from the host cell.

Integrated 4D Analysis of Intramuscular Fat Deposition: Quantitative Proteomic and Transcriptomic Studies in Wannanhua Pig Longissimus Dorsi Muscle

Wannanhua (WH) is a pig breed indigenous to Anhui Province, China. This breed has a high intramuscular fat (IMF) content, making it an ideal model for investigating lipid deposition mechanisms in pigs. IMF content is one of the main indicators of meat quality in pigs and is regulated by multiple genes and metabolic pathways. Building upon our prior transcriptomic investigation, the present study focused on the longissimus dorsi muscle tissue of Wannanhua (WH) pigs in the rapid fat-deposition stages (120 and 240 days of age). Employing 4D label-free quantitative proteomic analysis, we identified 106 differentially expressed proteins (DEPs). Parallel reaction monitoring (PRM) technology was used to verify the DEPs, and the results showed that the 4D label-free results were reliable and valid. Functional enrichment and protein-protein interaction analyses showed that the DEPs were mainly involved in the skeletal-muscle-associated structural proteins, mitochondria, energy metabolism, and fatty acid metabolism. By integrating transcriptomic data, we identified seven candidate genes including ACADL, ACADM, ANKRD2, MYOZ2, TNNI1, UCHL1, and ART3 that play a regulatory role in fat deposition and muscle development. These findings establish a theoretical foundation for future analyses of lipid deposition traits, contributing to potential enhancements in pig meat quality during breeding and advancing the selection process for Chinese indigenous breeds.

Construction of LncRNA-Related ceRNA Networks in Longissimus Dorsi Muscle of Jinfen White Pigs at Different Developmental Stages

The development of skeletal muscle in pigs might determine the quality of pork. In recent years, long non-coding RNAs (lncRNAs) have been found to play an important role in skeletal muscle growth and development. In this study, we investigated the whole transcriptome of the longissimus dorsi muscle (LDM) of Jinfen White pigs at three developmental stages (1, 90, and 180 days) and performed a comprehensive analysis of lncRNAs, mRNAs, and micro-RNAs (miRNAs), aiming to find the key regulators and interaction networks in Jinfen White pigs. A total of 2638 differentially expressed mRNAs (DE mRNAs) and 982 differentially expressed lncRNAs (DE lncRNAs) were identified. Compared with JFW_1d, there were 497 up-regulated and 698 down-regulated DE mRNAs and 212 up-regulated and 286 down-regulated DE lncRNAs in JFW_90d, respectively. In JFW_180d, there were 613 up-regulated and 895 down-regulated DE mRNAs and 184 up-regulated and 131 down-regulated DE lncRNAs compared with JFW_1d. There were 615 up-regulated and 477 down-regulated DE mRNAs and 254 up-regulated and 355 down-regulated DE lncRNAs in JFW_180d compared with JFW_90d. Compared with mRNA, lncRNA has fewer exons, fewer ORFs, and a shorter length. We performed GO and KEGG pathway functional enrichment analysis for DE mRNAs and the potential target genes of DE lncRNAs. As a result, several pathways are involved in muscle growth and development, such as the PI3K-Akt, MAPK, hedgehog, and hippo signaling pathways. These are among the pathways through which mRNA and lncRNAs function. As part of this study, bioinformatic screening was used to identify miRNAs and DE lncRNAs that could act as ceRNAs. Finally, we constructed an lncRNA-miRNA-mRNA regulation network containing 26 mRNAs, 7 miRNAs, and 17 lncRNAs; qRT-PCR was used to verify the key genes in these networks. Among these, XLOC_022984/miR-127/ENAH and XLOC_016847/miR-486/NRF1 may function as key ceRNA networks. In this study, we obtained transcriptomic profiles from the LDM of Jinfen White pigs at three developmental stages and screened out lncRNA-miRNA-mRNA regulatory networks that may provide crucial information for the further exploration of the molecular mechanisms during skeletal muscle development.

LncRNA NONHSAT227443.1 Confers Esophageal Squamous Cell Carcinoma Chemotherapy Resistance by Activating PI3K/AKT Signaling via Targeting MRTFB

INTRODUCTION

Esophageal cancer presents significant challenges due to limited treatment options and poor prognosis, particularly in advanced stages. Dysregulated long non-coding RNAs (lncRNAs) are implicated in cancer progression and treatment resistance. This study investigated the roles of dysregulated lncRNA NONHSAT227443.1, identified through lncRNA-seq, and its downstream target gene MRTFB in esophageal squamous cell carcinoma (ESCC).

METHODS

Dysregulated lncRNAs were identified through lncRNA-seq in esophageal cancer tissues with varying chemotherapy response. The regulatory interaction of overexpressed NONHSAT227443.1 was assessed using quantitative real-time polymerase chain reaction (qRT-PCR) and western blotting. Functional assays, including cell viability, cell proliferation, and flow cytometry analyses, were performed to comprehensively investigate the influence of NONHSAT227443.1 and its downstream molecules on ESCC.

RESULTS

NONHSAT227443.1 was significantly overexpressed in paclitaxel plus platinum chemotherapy non-responders and esophageal cancer cell lines. Chemotherapy exposure led to diminished NONHSAT227443.1 expression. NONHSAT227443.1 negatively regulated MRTFB expression, and their combined dysregulation correlated with increased cancer activity, proliferation, and suppressed apoptosis. Diminished MRTFB expression was associated with PI3K/AKT pathway activation.

CONCLUSION

Our study provides insights into NONHSAT227443.1 and MRTFB roles in esophageal cancer, contributing to aggressive traits and treatment resistance. NONHSAT227443.1 and MRTFB may serve as potential therapeutic targets to enhance the response to paclitaxel plus platinum chemotherapy in non-responsive cases.

The roles of miRNAs in adult skeletal muscle satellite cells

Satellite cells are bona fide muscle stem cells that are indispensable for successful post-natal muscle growth and regeneration after severe injury. These cells also participate in adult muscle adaptation in several capacities. MicroRNAs (miRNAs) are post-transcriptional regulators of mRNA that are implicated in several aspects of stem cell function. There is evidence to suggest that miRNAs affect satellite cell behavior in vivo during development and myogenic progenitor behavior in vitro, but the role of miRNAs in adult skeletal muscle satellite cells is less studied. In this review, we provide evidence for how miRNAs control satellite cell function with emphasis on satellite cells of adult skeletal muscle in vivo. We first outline how miRNAs are indispensable for satellite cell viability and control the phases of myogenesis. Next, we discuss the interplay between miRNAs and myogenic cell redox status, senescence, and communication to other muscle-resident cells during muscle adaptation. Results from recent satellite cell miRNA profiling studies are also summarized. In vitro experiments in primary myogenic cells and cell lines have been invaluable for exploring the influence of miRNAs, but we identify a need for novel genetic tools to further interrogate how miRNAs control satellite cell behavior in adult skeletal muscle in vivo.

Role of Actin-Binding Proteins in Skeletal Myogenesis

Maintenance of skeletal muscle quantity and quality is essential to ensure various vital functions of the body. Muscle homeostasis is regulated by multiple cytoskeletal proteins and myogenic transcriptional programs responding to endogenous and exogenous signals influencing cell structure and function. Since actin is an essential component in cytoskeleton dynamics, actin-binding proteins (ABPs) have been recognized as crucial players in skeletal muscle health and diseases. Hence, dysregulation of ABPs leads to muscle atrophy characterized by loss of mass, strength, quality, and capacity for regeneration. This comprehensive review summarizes the recent studies that have unveiled the role of ABPs in actin cytoskeletal dynamics, with a particular focus on skeletal myogenesis and diseases. This provides insight into the molecular mechanisms that regulate skeletal myogenesis via ABPs as well as research avenues to identify potential therapeutic targets. Moreover, this review explores the implications of non-coding RNAs (ncRNAs) targeting ABPs in skeletal myogenesis and disorders based on recent achievements in ncRNA research. The studies presented here will enhance our understanding of the functional significance of ABPs and mechanotransduction-derived myogenic regulatory mechanisms. Furthermore, revealing how ncRNAs regulate ABPs will allow diverse therapeutic approaches for skeletal muscle disorders to be developed.

The role of PI3K/AKT signaling pathway in myocardial ischemia-reperfusion injury

Myocardial ischemia has a high incidence and mortality rate, and reperfusion is currently the standard intervention. However, reperfusion may lead to further myocardial damage, known as myocardial ischemia/reperfusion injury (MIRI). There are currently no effective clinical treatments for MIRI. The PI3K/Akt signaling pathway is involved in cardiovascular health and disease and plays an important role in reducing myocardial infarct size and restoring cardiac function after MIRI. Activation of the PI3K/Akt pathway provides myocardial protection through synergistic upregulation of antioxidant, anti-inflammatory, and autophagy activities and inhibition of mitochondrial dysfunction and cardiomyocyte apoptosis. Many studies have shown that PI3K/Akt has a significant protective effect against MIRI. Here, we reviewed the molecular regulation of PI3K/Akt in MIRI and summarized the molecular mechanism by which PI3K/Akt affects MIRI, the effects of ischemic preconditioning and ischemic postconditioning, and the role of related drugs or activators targeting PI3K/Akt in MIRI, providing novel insights for the formulation of myocardial protection strategies. This review provides evidence of the role of PI3K/Akt activation in MIRI and supports its use as a therapeutic target.

Idiopathic inflammatory myopathy and non-coding RNA

Idiopathic inflammatory myopathies (IIMs) are common autoimmune diseases that affect skeletal muscle quality and function. The lack of an early diagnosis and treatment can lead to irreversible muscle damage. Non-coding RNAs (ncRNAs) play an important role in inflammatory transfer, muscle regeneration, differentiation, and regulation of specific antibody levels and pain in IIMs. ncRNAs can be detected in blood and hair; therefore, ncRNAs detection has great potential for diagnosing, preventing, and treating IIMs in conjunction with other methods. However, the specific roles and mechanisms underlying the regulation of IIMs and their subtypes remain unclear. Here, we review the mechanisms by which micro RNAs and long non-coding RNA-messenger RNA networks regulate IIMs to provide a basis for ncRNAs use as diagnostic tools and therapeutic targets for IIMs.

Gender Differences and miRNAs Expression in Cancer: Implications on Prognosis and Susceptibility

MicroRNAs are small, noncoding molecules of about twenty-two nucleotides with crucial roles in both healthy and pathological cells. Their expression depends not only on genetic factors, but also on epigenetic mechanisms like genomic imprinting and inactivation of X chromosome in females that influence in a sex-dependent manner onset, progression, and response to therapy of different diseases like cancer. There is evidence of a correlation between miRNAs, sex, and cancer both in solid tumors and in hematological malignancies; as an example, in lymphomas, with a prevalence rate higher in men than women, miR-142 is "silenced" because of its hypermethylation by DNA methyltransferase-1 and it is blocked in its normal activity of regulating the migration of the cell. This condition corresponds in clinical practice with a more aggressive tumor. In addition, cancer treatment can have advantages from the evaluation of miRNAs expression; in fact, therapy with estrogens in hepatocellular carcinoma determines an upregulation of the oncosuppressors miR-26a, miR-92, and miR-122 and, consequently, apoptosis. The aim of this review is to present an exhaustive collection of scientific data about the possible role of sex differences on the expression of miRNAs and the mechanisms through which miRNAs influence cancerogenesis, autophagy, and apoptosis of cells from diverse types of tumors.

Skeletal Muscle MicroRNA Patterns in Response to a Single Bout of Exercise in Females: Biomarkers for Subsequent Training Adaptation?

microRNAs (miRs) have been proposed as a promising new class of biomarkers in the context of training adaptation. Using microarray analysis, we studied skeletal muscle miR patterns in sedentary young healthy females (n = 6) before and after a single submaximal bout of endurance exercise ('reference training'). Subsequently, participants were subjected to a structured training program, consisting of six weeks of moderate-intensity continuous endurance training (MICT) and six weeks of high-intensity interval training (HIIT) in randomized order. In vastus lateralis muscle, we found significant downregulation of myomiRs, specifically miR-1, 133a-3p, and -5p, -133b, and -499a-5p. Similarly, exercise-associated miRs-23a-3p, -378a-5p, -128-3p, -21-5p, -107, -27a-3p, -126-3p, and -152-3p were significantly downregulated, whereas miR-23a-5p was upregulated. Furthermore, in an untargeted approach for differential expression in response to acute exercise, we identified n = 35 miRs that were downregulated and n = 20 miRs that were upregulated by factor 4.5 or more. Remarkably, KEGG pathway analysis indicated central involvement of this set of miRs in fatty acid metabolism. To reproduce these data in a larger cohort of all-female subjects (n = 29), qPCR analysis was carried out on n = 15 miRs selected from the microarray, which confirmed their differential expression. Furthermore, the acute response, i.e., the difference between miR concentrations before and after the reference training, was correlated with changes in maximum oxygen uptake (V̇O₂max) in response to the training program. Here, we found that miRs-199a-3p and -19b-3p might be suitable acute-response candidates that correlate with individual degrees of training adaptation in females.

Green tea actions on miRNAs expression – An update

Compounds derived from plants have been widely studied in the context of metabolic diseases and associated clinical conditions. In this regard, although the effects of Camellia sinensis plant, from which various types of teas, such as green tea, originate, have been vastly reported in the literature, the mechanisms underlying these effects remain elusive. A deep search of the literature showed that green tea's action in different cells, tissues, and diseases is an open field in the research of microRNAs (miRNAs). miRNAs are important communicator molecules between cells in different tissues implicated in diverse cellular pathways. They have emerged as an important linkage between physiology and pathophysiology, raising the issue of polyphenols can act also by changing miRNA expression. miRNAs are short, non-coding endogenous RNA, which silence the gene functions by targeting messenger RNA (mRNA) through degradation or translation repression. Therefore, the aim of this review is to present the studies that show the main compounds of green tea modulating the expression of miRNAs in inflammation, adipose tissue, skeletal muscle, and liver. We provide an overview of a few studies that have tried to demonstrate the role of miRNAs associated with the beneficial effects of compounds from green tea. We have emphasized that there is still a considerable gap in the literature investigating the role and likely involvement of miRNAs in the extensive beneficial health effects of green tea compounds already described, indicating miRNAs as potential polyphenols' mediators with a promising field to be investigated.

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.

Differential Effect of Extracellular Vesicles Derived from Plasmodium falciparum-Infected Red Blood Cells on Monocyte Polarization

Malaria is a life-threatening tropical arthropod-borne disease caused by Plasmodium spp. Monocytes are the primary immune cells to eliminate malaria-infected red blood cells. Thus, the monocyte's functions are one of the crucial factors in controlling parasite growth. It is reasoned that the activation or modulation of monocyte function by parasite products might dictate the rate of disease progression. Extracellular vesicles (EVs), microvesicles, and exosomes, released from infected red blood cells, mediate intercellular communication and control the recipient cell function. This study aimed to investigate the physical characteristics of EVs derived from culture-adapted P. falciparum isolates (Pf-EVs) from different clinical malaria outcomes and their impact on monocyte polarization. The results showed that all P. falciparum strains released similar amounts of EVs with some variation in size characteristics. The effect of Pf-EV stimulation on M1/M2 monocyte polarization revealed a more pronounced effect on CD14+CD16+ intermediate monocytes than the CD14+CD16- classical monocytes with a marked induction of Pf-EVs from a severe malaria strain. However, no difference in the levels of microRNAs (miR), miR-451a, miR-486, and miR-92a among Pf-EVs derived from virulent and nonvirulent strains was found, suggesting that miR in Pf-EVs might not be a significant factor in driving M2-like monocyte polarization. Future studies on other biomolecules in Pf-EVs derived from the P. falciparum strain with high virulence that induce M2-like polarization are therefore recommended.

The Role of microRNA in the Development, Diagnosis, and Treatment of Cardiovascular Disease: Recent Developments

Since their discovery in 1993, microRNAs (miRNAs) have emerged as important regulators of many crucial cellular processes, and their dysregulation have been shown to contribute to multiple pathologic conditions, including cardiovascular disease (CVD). miRNAs have been found to regulate the expression of various genes involved in cardiac development and function and in the development and progression of CVD. Many miRNAs are master regulators fine-tuning the expression of multiple, often interrelated, genes involved in inflammation, apoptosis, fibrosis, senescence, and other processes crucial for the development of different forms of CVD. This article presents a review of recent developments in our understanding of the role of miRNAs in the development of CVD and surveys their potential applicability as therapeutic targets and biomarkers to facilitate CVD diagnosis, prognosis, and treatment. There are currently multiple potential miRNA-based therapeutic agents in different stages of development, which can be grouped into two classes: miRNA mimics (replicating the sequence and activity of their corresponding miRNAs) and antagomiRs (antisense inhibitors of specific miRNAs). However, in spite of promising preliminary data and our ever-increasing knowledge about the mechanisms of action of specific miRNAs, miRNA-based therapeutics and biomarkers have yet to be approved for clinical applications. SIGNIFICANCE STATEMENT: Over the last few years microRNAs have emerged as crucial, specific regulators of the cardiovascular system and in the development of cardiovascular disease, by posttranscriptional regulation of their target genes. The minireview presents the most recent developments in this area of research, including the progress in diagnostic and therapeutic applications of microRNAs. microRNAs seem very promising candidates for biomarkers and therapeutic agents, although some challenges, such as efficient delivery and unwanted effects, need to be resolved.

Small ankyrin 1 (sANK1) promotes docetaxel resistance in castration-resistant prostate cancer cells by enhancing oxidative phosphorylation

Docetaxel (DTX) plays an important role in treating advanced prostate cancer (PCa). However, nearly all patients receiving DTX therapy ultimately progress to DTX resistance. How to address DTX resistance in PCa remains a key challenge for all urologists. Small ankyrin 1 (sAnk1) is an integral membrane protein in the endoplasmic reticulum. In the present study, we identified that sAnk1 is upregulated in PCa tissues and is positively associated with DTX therapy resistance in PCa. Further investigation demonstrated that overexpression of sAnk1 can significantly increase the DTX-resistant ability of PCa cells in vitro and in vivo. In addition, overexpression of sAnk1 could enhance oxidative phosphorylation (OXPHOS) levels in PCa cells, which was consistent with the higher OXPHOS levels observed in DTX-resistant PCa cells as compared to DTX-sensitive PCa cells. sAnk1 was also found to interact with polypyrimidine-tract-binding protein (PTBP1), an alternative splicing factor, and suppressed PTBP1-mediated alternative splicing of the pyruvate kinase gene (PKM). Thus, overexpression of sAnk1 decreased the ratio of PKM2/PKM1, enhanced the OXPHOS level, and ultimately promoted the resistance of PCa cells to DTX. In summary, our data suggest that sAnk1 enhances DTX resistance in PCa cells.

MicroRNAs as the Sentinels of Redox and Hypertrophic Signalling

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

Recent advances in cell-based and cell-free therapeutic approaches for sarcopenia

Sarcopenia is a progressive loss of muscle mass and function that is connected with increased hospital expenditures, falls, fractures, and mortality. Although muscle loss has been related to aging, injury, hormonal imbalances, and diseases such as malignancies, chronic obstructive pulmonary disease, heart failure, and kidney failure, the underlying pathogenic mechanisms of sarcopenia are unclear. Exercise-based interventions and multimodal strategies are currently being considered as potential therapeutic approaches to prevent or treat these diseases. Although drug therapy research is ongoing, no drug has yet been proven to have a substantial safety and clinical value to be the first drug therapy to be licensed for sarcopenia. To better understand the molecular alterations underlying sarcopenia and effective treatments, we review leading research and available findings from the systemic change to the muscle-specific microenvironment. Furthermore, we explore possible mechanisms of sarcopenia and provide new knowledge for the development of novel cell-free and cell-based therapeutics. This review will assist researchers in developing better therapies to improve muscle health in the elderly.

Small RNA sequencing in hypoxic naked mole-rat hearts suggests microRNA regulation of RNA- and translation-related processes

The naked mole-rat (Heterocephalus glaber) regularly endures intermittent periods of hypoxia in its burrows, surviving in part due to metabolic rate depression (MRD)-a strategy of conserving cellular resources by downregulating nonessential gene expression and reorganizing cellular processes. MicroRNA (miRNA) are short, noncoding RNAs already implicated for their roles in numerous models of extreme environmental stress; given their rapid, reversible nature, they are ideal for implementing MRD. We performed small RNA sequencing on cardiac tissue from normoxic vs. 24 h hypoxic naked mole-rats, and used bioinformatics to predict eighteen miRNAs which may be differentially regulated during hypoxia. Gene Ontology and KEGG pathway mapping further suggest these miRNAs play roles in largely translation-related functions, including RNA processing and catabolism.

Selective Loading and Variations in the miRNA Profile of Extracellular Vesicles from Endothelial-like Cells Cultivated under Normoxia and Hypoxia

Endothelial-like cells may be obtained from CD133⁺ mononuclear cells isolated from human umbilical cord blood (hUCB) and expanded using endothelial-inducing medium (E-CD133 cells). Their use in regenerative medicine has been explored by the potential not only to form vessels but also by the secretion of bioactive elements. Extracellular vesicles (EVs) are prominent messengers of this paracrine activity, transporting bioactive molecules that may guide cellular response under different conditions. Using RNA-Seq, we characterized the miRNA content of EVs derived from E-CD133 cells cultivated under normoxia (N-EVs) and hypoxia (H-EVs) and observed that changing the O₂ status led to variations in the selective loading of miRNAs in the EVs. In silico analysis showed that among the targets of differentially loaded miRNAs, there are transcripts involved in pathways related to cell growth and survival, such as FoxO and HIF-1 pathways. The data obtained reinforce the pro-regenerative potential of EVs obtained from E-CD133 cells and shows that fine tuning of their properties may be regulated by culture conditions.

miR-486 is essential for muscle function and suppresses a dystrophic transcriptome

miR-486 is a muscle-enriched microRNA, or "myomiR," that has reduced expression correlated with Duchenne muscular dystrophy (DMD). To determine the function of miR-486 in normal and dystrophin-deficient muscles and elucidate miR-486 target transcripts in skeletal muscle, we characterized mir-486 knockout mice (mir-486 KO). mir-486 KO mice developed disrupted myofiber architecture, decreased myofiber size, decreased locomotor activity, increased cardiac fibrosis, and metabolic defects were exacerbated in mir-486 KO:mdx 5cv (DKO) mice. To identify direct in vivo miR-486 muscle target transcripts, we integrated RNA sequencing and chimeric miRNA eCLIP sequencing to identify key transcripts and pathways that contribute towards mir-486 KO and dystrophic disease pathologies. These targets included known and novel muscle metabolic and dystrophic structural remodeling factors of muscle and skeletal muscle contractile transcript targets. Together, our studies identify miR-486 as essential for normal muscle function, a driver of pathological remodeling in dystrophin-deficient muscle, a useful biomarker for dystrophic disease progression, and highlight the use of multiple omic platforms to identify in vivo microRNA target transcripts.

A new biomarker to enhance the radiosensitivity of hepatocellular cancer: miRNAs

Aims: This review summarizes findings regarding miRNAs that modulate radiation in hepatocellular carcinoma (HCC) and evaluates their potential clinical therapeutic uses. Materials & methods: We searched the relevant English-language medical databases for papers on miRNAs and radiation therapy for tumors to identify miRNAs that are linked with radiosensitivity and radioresistance, focusing on those associated with HCC radiation. Results: There were 88 papers assessed for miRNAs associated with tumor radiation, 56 of which dealt with radiosensitization, 21 with radioresistance and 11 with radiosensitization for HCC. Conclusion: Further work in this area would enable future evaluation of radiation responses and the potential use of miRNAs as therapeutic agents in HCC patients.

circMEF2D Negatively Regulated by HNRNPA1 Inhibits Proliferation and Differentiation of Myoblasts via miR-486-PI3K/AKT Axis

Circular RNA (circRNA) is a form of endogenous RNA that can regulate gene expression and participate in the regulation of myogenesis. However, the molecular mechanisms and potential roles of circRNAs in bovine muscle development remain largely unknown. Nevertheless, the RNA splicing factors regulating the biogenesis of bovine circRNA have not yet been characterized. In this study, we identified a novel circRNA, circMEF2D, formed by back-splicing of constitutive exons (exons 5-7) of the bovine MEF2D gene. Functional assays showed that circMEF2D inhibited the proliferation and differentiation of bovine myoblasts. Importantly, we showed that circMEF2D regulated the PI3K-AKT signaling pathway through direct and competitive binding to miR-486. Furthermore, to explore the formation mechanism of circMEF2D, we explored the MEF2D gene alternative splicing progress. Four alternative linear variants of MEF2D were found. Due to its role in alternative splicing, the RNA-binding protein HNRNPA1 was selected for further study and the modulation of HNRNPA1 levels showed that it negatively regulated both back-splicing and linear splicing of MEF2D gene. Overall, in addition to the characterization of bovine circRNAs, these findings revealed the crucial role of HNRNPA1 in MEF2D gene alternative splicing and demonstrated a regulatory circMEF2D-miR-486-PI3K-AKT axis.

miRNA-486-5p: signaling targets and role in non-malignant disease

MicroRNAs (miRNAs) are short non-coding RNAs, highly conserved between species, that are powerful regulators of gene expression. Aberrant expression of miRNAs alters biological processes and pathways linked to human disease. miR-486-5p is a muscle-enriched miRNA localized to the cytoplasm and nucleus, and is highly abundant in human plasma and enriched in small extracellular vesicles. Studies of malignant and non-malignant diseases, including kidney diseases, have found correlations with circulating miR-486-5p levels, supporting its role as a potential biomarker. Pre-clinical studies of non-malignant diseases have identified miR-486-5p targets that regulate major signaling pathways involved in cellular proliferation, migration, angiogenesis, and apoptosis. Validated miR-486-5p targets include phosphatase and tensin homolog (PTEN) and FoXO1, whose suppression activates phosphatidyl inositol-3-kinase (PI3K)/Akt signaling. Targeting of Smad1/2/4 and IGF-1 by miR-486-5p inhibits transforming growth factor (TGF)-β and insulin-like growth factor-1 (IGF-1) signaling, respectively. Other miR-486-5p targets include matrix metalloproteinase-19 (MMP-19), Sp5, histone acetyltransferase 1 (HAT1), and nuclear factor of activated T cells-5 (NFAT5). In this review, we examine the biogenesis, regulation, validated gene targets and biological effects of miR-486-5p in non-malignant diseases.

MicroRNA expression signature in the striated and smooth adductor muscles of Yesso scallop Patinopecten yessoensis

Increasing evidences point to the potential role of microRNAs (miRNAs) in muscle growth and development in animals. However, knowledge on the identity of miRNAs and their targets in molluscs remains largely unknown. Scallops have one large adductor muscle, composed of fast (striated) and slow (smooth) muscle types, which display great differences in muscle fibers, meat quality, cell types and molecular components. In the present study, we performed a comprehensive investigation of miRNA transcriptomes in fast and slow adductor muscles of Yesso scallop Patinopecten yessoensis. As a result, 47 differentially expressed miRNAs representing ten miRNA families were identified between the striated and smooth adductor muscles. The KEGG enrichment analysis of their target genes were mainly associated with amino acid metabolism, energy metabolism and glycan biosynthesis. The target genes of miR-133 and miR-71 were validated by the dual-luciferase reporter assays and miRNA antagomir treatment in vivo. The identification and functional validation of these different miRNAs in scallops will greatly help our understanding of miRNA regulatory mechanism that achieves the unique muscle phenotypes in scallops. The present findings provide the direct evidences for muscle-specific miRNAs involved in muscle growth and differentiation in molluscs.

Skeletal muscle-specific overexpression of miR-486 limits mammary tumor-induced skeletal muscle functional limitations

miR-486 is a myogenic microRNA, and its reduced skeletal muscle expression is observed in muscular dystrophy. Transgenic overexpression of miR-486 using muscle creatine kinase promoter (MCK-miR-486) partially rescues muscular dystrophy phenotype. We had previously demonstrated reduced circulating and skeletal muscle miR-486 levels with accompanying skeletal muscle defects in mammary tumor models. To determine whether skeletal muscle miR-486 is functionally similar in dystrophies and cancer, we performed functional limitations and biochemical studies of skeletal muscles of MMTV-Neu mice that mimic HER2+ breast cancer and MMTV-PyMT mice that mimic luminal subtype B breast cancer and these mice crossed to MCK-miR-486 mice. miR-486 significantly prevented tumor-induced reduction in muscle contraction force, grip strength, and rotarod performance in MMTV-Neu mice. In this model, miR-486 reversed cancer-induced skeletal muscle changes, including loss of p53, phospho-AKT, and phospho-laminin alpha 2 (LAMA2) and gain of hnRNPA0 and SRSF10 phosphorylation. LAMA2 is a part of the dystrophin-associated glycoprotein complex, and its loss of function causes congenital muscular dystrophy. Complementing these beneficial effects on muscle, miR-486 indirectly reduced tumor growth and improved survival, which is likely due to systemic effects of miR-486 on production of pro-inflammatory cytokines such as IL-6. Thus, similar to dystrophy, miR-486 has the potential to reverse skeletal muscle defects and cancer burden.

SRF: a seriously responsible factor in cardiac development and disease

The molecular mechanisms that regulate embryogenesis and cardiac development are calibrated by multiple signal transduction pathways within or between different cell lineages via autocrine or paracrine mechanisms of action. The heart is the first functional organ to form during development, which highlights the importance of this organ in later stages of growth. Knowledge of the regulatory mechanisms underlying cardiac development and adult cardiac homeostasis paves the way for discovering therapeutic possibilities for cardiac disease treatment. Serum response factor (SRF) is a major transcription factor that controls both embryonic and adult cardiac development. SRF expression is needed through the duration of development, from the first mesodermal cell in a developing embryo to the last cell damaged by infarction in the myocardium. Precise regulation of SRF expression is critical for mesoderm formation and cardiac crescent formation in the embryo, and altered SRF levels lead to cardiomyopathies in the adult heart, suggesting the vital role played by SRF in cardiac development and disease. This review provides a detailed overview of SRF and its partners in their various functions and discusses the future scope and possible therapeutic potential of SRF in the cardiovascular system.

MiR-486-5p Targets CD133+ Lung Cancer Stem Cells through the p85/AKT Pathway

Despite improvements in therapies and screening strategies, lung cancer prognosis still remains dismal, especially for metastatic tumors. Cancer stem cells (CSCs) are endowed with properties such as chemoresistance, dissemination, and stem-like features, that make them one of the main causes of the poor survival rate of lung cancer patients. MicroRNAs (miRNAs), small molecules regulating gene expression, have a role in lung cancer development and progression. In particular, miR-486-5p is an onco-suppressor miRNA found to be down-modulated in the tumor tissue of lung cancer patients. In this study, we investigate the role of this miRNA in CD133+ lung CSCs and evaluate the therapeutic efficacy of coated cationic lipid-nanoparticles entrapping the miR-486-5p miRNA mimic (CCL-486) using lung cancer patient-derived xenograft (PDX) models. In vitro, miR-486-5p overexpression impaired the PI3K/Akt pathway and decreased lung cancer cell viability. Moreover, miR-486-5p overexpression induced apoptosis also in CD133+ CSCs, thus affecting the in vivo tumor-initiating properties of these cells. Finally, we demonstrated that in vivo CCL-486 treatment decreased CD133+ percentage and inhibited tumor growth in PDX models. In conclusion, we provided insights on the efficacy of a novel miRNA-based compound to hit CD133+ lung CSCs, setting the basis for new combined therapeutic strategies.

miR-486-5p expression is regulated by DNA methylation in osteosarcoma

Background

Osteosarcoma is the most common primary malignant tumour of bone occurring in children and young adolescents and is characterised by complex genetic and epigenetic changes. The miRNA miR-486-5p has been shown to be downregulated in osteosarcoma and in cancer in general.

Results

To investigate if the mir-486 locus is epigenetically regulated, we integrated DNA methylation and miR-486-5p expression data using cohorts of osteosarcoma cell lines and patient samples. A CpG island in the promoter of the ANK1 host gene of mir-486 was shown to be highly methylated in osteosarcoma cell lines as determined by methylation-specific PCR and direct bisulfite sequencing. High methylation levels were seen for osteosarcoma patient samples, xenografts and cell lines based on quantitative methylation-specific PCR. 5-Aza-2′-deoxycytidine treatment of osteosarcoma cell lines caused induction of miR-486-5p and ANK1, indicating common epigenetic regulation in osteosarcoma cell lines. When overexpressed, miR-486-5p affected cell morphology.

Conclusions

miR-486-5p represents a highly cancer relevant, epigenetically regulated miRNA in osteosarcoma, and this knowledge contributes to the understanding of osteosarcoma biology.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12864-022-08346-6.

MiR-486 attenuates cardiac ischemia/reperfusion injury and mediates the beneficial effect of exercise for myocardial protection

Exercise and its regulated molecules have myocardial protective effects against cardiac ischemia/reperfusion (I/R) injury. The muscle-enriched miR-486 was previously identified to be upregulated in exercised heart, which prompted us to investigate the functional roles of miR-486 in cardiac I/R injury and to further explore its potential in contributing to exercise-induced protection against I/R injury. Our data showed that miR-486 was significantly downregulated in the heart upon cardiac I/R injury. Both preventive and therapeutic interventions of adeno-associated virus 9 (AAV9)-mediated miR-486 overexpression could reduce cardiac I/R injury. Using AAV9 expressing miR-486 with cTnT promoter, we further demonstrated that cardiac muscle cell-targeted miR-486 overexpression was also sufficient to protect against cardiac I/R injury. Consistently, miR-486 was downregulated in oxygen glucose deprivation/reperfusion (OGDR)-stressed cardiomyocytes, while upregulating miR-486 inhibited cardiomyocyte apoptosis through PTEN and FoxO1 inhibition and AKT/mTOR activation. Finally, we observed that miR-486 was necessary for exercise-induced protection against cardiac I/R injury. In conclusion, miR-486 is protective against cardiac I/R injury and myocardial apoptosis through targeting PTEN and FoxO1 and activation of the AKT/mTOR pathway, and mediates the beneficial effect of exercise for myocardial protection. Increasing miR-486 might be a promising therapeutic strategy for myocardial protection.