Inhibition of miR-29 by TGF-beta-Smad3 signaling through dual mechanisms promotes transdifferentiation of mouse myoblasts into myofibroblasts

Non-coding RNA therapeutics in the treatment of heart failure

Non-coding RNA (ncRNA) therapeutics can target either ncRNAs or conventional messenger RNA, offering both superior pharmacokinetics and selectivity to conventional therapies and addressing new, previously unexplored pathways. Although no ncRNA has yet been approved for the treatment of heart failure, in this review we present five most promising pathways and agents that either are in human clinical trials or offer great promise in the near future.

Exploring the role of pericardial miRNAs and exosomes in modulating cardiac fibrosis

The potential of the pericardial space as a therapeutic delivery tool for cardiac fibrosis and heart failure (HF) treatment has yet to be elucidated. Recently, miRNAs and exosomes have been discovered to be present in human pericardial fluid (PF). Novel studies have shown characteristic human PF miRNA compositions associated with cardiac diseases and higher miRNA expressions in PF compared to peripheral blood. Five key studies found differentially expressed miRNAs in HF, angina pectoris, aortic stenosis, ventricular tachycardia, and congenital heart diseases with either atrial fibrillation or sinus rhythm. As miRNA-based therapeutics for cardiac fibrosis and HF showed promising results in several in vivo studies for multiple miRNAs, we hypothesize a potential role of miRNA-based therapeutics delivered through the pericardial cavity. This is underlined by the favorable results of the first phase 1b clinical trial in this emerging field. Presenting the first human miRNA antisense drug trial, inhibition of miR-132 by intravenous administration of a novel antisense oligonucleotide, CDR132L, established efficacy in reducing miR-132 in plasma samples in a dose-dependent manner. We screened the literature, provided an overview of the miRNAs and exosomes present in PF, and drew a connection to those miRNAs previously elucidated in cardiac fibrosis and HF. Further, we speculate about clinical implications and potential delivery methods.

Microneedle Patch Loaded with Exosomes Containing MicroRNA-29b Prevents Cardiac Fibrosis after Myocardial Infarction

Myocardial infarction (MI) is a cardiovascular disease that poses a serious threat to human health. Uncontrolled and excessive cardiac fibrosis after MI has been recognized as a primary contributor to mortality by heart failure. Thus, prevention of fibrosis or alleviation of fibrosis progression is important for cardiac repair. To this end, a biocompatible microneedle (MN) patch based on gelatin is fabricated to load exosomes containing microRNA-29b (miR-29b) mimics with antifibrotic activity to prevent excessive cardiac fibrosis after MI. Exosomes are isolated from human umbilical cord mesenchymal stem cells and loaded with miR-29b mimics via electroporation, which can be internalized effectively in cardiac fibroblasts to upregulate the expression of miR-29b and downregulate the expression of fibrosis-related proteins. After being implanted in the infarcted heart of a mouse MI model, the MN patch can increase the retention of loaded exosomes in the infarcted myocardium, leading to alleviation of inflammation, reduction of the infarct size, inhibition of fibrosis, and improvement of cardiac function. This design explored the MN patch as a suitable platform to deliver exosomes containing antifibrotic biomolecules locally for the prevention of cardiac fibrosis, showing the potential for MI treatment in clinical applications.

IFN-γ blockade after genetic inhibition of PD-1 aggravates skeletal muscle damage and impairs skeletal muscle regeneration

BACKGROUND

Innate immune responses play essential roles in skeletal muscle recovery after injury. Programmed cell death protein 1 (PD-1) contributes to skeletal muscle regeneration by promoting macrophage proinflammatory to anti-inflammatory phenotype transition. Interferon (IFN)-γ induces proinflammatory macrophages that appear to hinder myogenesis in vitro. Therefore, we tested the hypothesis that blocking IFN-γ in PD-1 knockout mice may dampen inflammation and promote skeletal muscle regeneration via regulating the macrophage phenotype and neutrophils.

METHODS

Anti-IFN-γ antibody was administered in PD-1 knockout mice, and cardiotoxin (CTX) injection was performed to induce acute skeletal muscle injury. Hematoxylin and eosin (HE) staining was used to view morphological changes of injured and regenerated skeletal muscle. Masson's trichrome staining was used to assess the degree of fibrosis. Gene expressions of proinflammatory and anti-inflammatory factors, fibrosis-related factors, and myogenic regulator factors were determined by real-time polymerase chain reaction (PCR). Changes in macrophage phenotype were examined by western blot and real-time PCR. Immunofluorescence was used to detect the accumulation of proinflammatory macrophages, anti-inflammatory macrophages, and neutrophils.

RESULTS

IFN-γ blockade in PD-1 knockout mice did not alleviate skeletal muscle damage or improve regeneration following acute cardiotoxin-induced injury. Instead, it exacerbated skeletal muscle inflammation and fibrosis, and impaired regeneration via inhibiting macrophage accumulation, blocking macrophage proinflammatory to anti-inflammatory transition, and enhancing infiltration of neutrophils.

CONCLUSION

IFN-γ is crucial for efficient skeletal muscle regeneration in the absence of PD-1.

The Preventive Effect of Specific Collagen Peptides against Dexamethasone-Induced Muscle Atrophy in Mice

Muscle atrophy, also known as muscle wasting, is the thinning of muscle mass due to muscle disuse, aging, or diseases such as cancer or neurological problems. Muscle atrophy is closely related to the quality of life and has high morbidity and mortality. However, therapeutic options for muscle atrophy are limited, so studies to develop therapeutic agents for muscle loss are always required. For this study, we investigated how orally administered specific collagen peptides (CP) affect muscle atrophy and elucidated its molecular mechanism using an in vivo model. We treated mice with dexamethasone (DEX) to induce a muscular atrophy phenotype and then administered CP (0.25 and 0.5 g/kg) for four weeks. In a microcomputed tomography analysis, CP (0.5 g/kg) intake significantly increased the volume of calf muscles in mice with DEX-induced muscle atrophy. In addition, the administration of CP (0.25 and 0.5 g/kg) restored the weight of the gluteus maximus and the fiber cross-sectional area (CSA) of the pectoralis major and calf muscles, which were reduced by DEX. CP significantly inhibited the mRNA expression of myostatin and the phosphorylation of Smad2, but it did not affect TGF-β, BDNF, or FNDC5 gene expression. In addition, AKT/mTOR, a central pathway for muscle protein synthesis and related to myostatin signaling, was enhanced in the groups that were administered CP. Finally, CP decreased serum albumin levels and increased TNF-α gene expression. Collectively, our in vivo results demonstrate that CP can alleviate muscle wasting through a multitude of mechanisms. Therefore, we propose CP as a supplement or treatment to prevent muscle atrophy.

Co-modified 3D printed β-tricalcium phosphate with magnesium and selenium promotes bone defect regeneration in ovariectomized rat

Magnesium (Mg) and Selenium (Se) are essential elements for bone health and have been studied extensively for its powerful osteogenesis and promoting bone regeneration. The purpose was to observe whether Co-modified 3D-printed β-tricalcium phosphate with Mg and Se could promote bone defect regeneration in an ovariectomized(OVX) rat model. The MC3T3-E1 cells were co-cultured with the leachate of β-TCP, Mg-TCP, and Mg/Se-TCP and induced to osteogenesis, and the cell viability, ROS, and osteogenic activity were observed by Cell Count Kit-8(CCK-8), fluorescent probe 2', 7'-dichlorofluorescin diacetate, Alkaline phosphatase (ALP) staining, Alizarin Red(RES) staining, western blotting(WB), and immunofluorescence. Then the β-TCP, Mg-TCP, and Mg/Se-TCP were implanted into the femoral epiphysis bone defect model of OVX rats for 12 weeks. Micro-CT and histology analysis were used to observe the therapeutic effect. In vitro results show that the cell mineralization and osteogenic activity of the Mg/Se-TCP group is significantly higher than the β-TCP group and Mg-TCP group. Protein expressions such as FOxO1, SIRT1, SOD2, Runx-2, Cola1a, and OC of the Mg/Se-TCP group are significantly higher than the Con group and the β-TCP group. The results of intracellular ROS and SIRT1 and SOD2 immunofluorescence showed that Mg/Se-TCP can restore the oxidative stress balance of osteoblasts. Micro-CT and histology analysis showed that treatment with Mg/Se-TCP showed the largest amount of bone tissue in the defect area (p < 0.05), and exhibited lower values of residual biological material (p < 0.05), compared to that of the β-TCP group and Mg-TCP group. Our research results confirm that Mg/Se-TCP can improve the activity and function of osteoblasts and enhance bone regeneration mediated by reducing intracellular ROS in OVX rat models. The release of Mg and Se during the degradation of Mg/Se-TCP can improve the local bone repair ability. At the same time, it can also inhibit cell ROS, and ultimately greatly promote local bone repair.

SMAD3 contributes to ascending aortic dilatation independent of transforming growth factor-beta in bicuspid and unicuspid aortic valve disease

We sought to determine whether there are differences in transforming growth factor-beta (TGFß) signaling in aneurysms associated with bicuspid (BAV) and unicuspid (UAV) aortic valves versus normal aortic valves. Ascending aortic aneurysms are frequently associated with BAV and UAV. The mechanisms are not yet clearly defined, but similarities to transforming growth factor-beta TGFß vasculopathies (i.e. Marfan, Loeys-Dietz syndromes) are reported. Non-dilated (ND) and aneurysmal (D) ascending aortic tissue was collected intra-operatively from individuals with a TAV (N = 10ND, 10D), BAV (N = 7ND, 8D) or UAV (N = 7ND, 8D). TGFß signaling and aortic remodeling were assessed through immuno-assays and histological analyses. TGFß1 was increased in BAV/UAV-ND aortas versus TAV (P = 0.02 and 0.04, respectively). Interestingly, TGFß1 increased with dilatation in TAV (P = 0.03) and decreased in BAV/UAV (P = 0.001). In TAV, SMAD2 and SMAD3 phosphorylation (pSMAD2, pSMAD3) increased with dilatation (all P = 0.04) and with TGFß1 concentration (P = 0.04 and 0.03). No relationship between TGFß1 and pSMAD2 or pSMAD3 was observed for BAV/UAV (all P > 0.05). pSMAD3 increased with dilatation in BAV/UAV aortas (P = 0.01), whereas no relationship with pSMAD2 was observed (P = 0.56). Elastin breaks increased with dilatation in all groups (all P < 0.05). In TAV, elastin degradation correlated with TGFß1, pSMAD2 and pSMAD3 (all P < 0.05), whereas in BAV and UAV aortas, elastin degradation correlated only with pSMAD3 (P = 0.0007). TGFß signaling through SMAD2/SMAD3 contributes to aortic remodeling in TAV, whereas TGFß-independent activation of SMAD3 may underlie aneurysm formation in BAV/UAV aortas. Therefore, SMAD3 should be further investigated as a therapeutic target against ascending aortic dilatation in general, and particularly in BAV/UAV patients.

Silibinin-modified Hydroxyapatite coating promotes the osseointegration of titanium rods by activation SIRT1/SOD2 signaling pathway in diabetic rats

The purpose of this study is to investigate the role of Silibinin (SIL)-modified Hydroxyapatite coating on osseointegration in diabetes in vivo and in vitro and explore the mechanism of osteogenic differentiation of MC3T3-E1. RT-qPCR, Immunofluorescence, and Western blot were used to measure the expression level of oxidative Stress Indicators and osteogenic markers proteins. Moreover, CCK-8 assay was conducted to detect cell viability in hyperglycemia. Alizarin red staining and alkaline phosphatase staining were used to examine osteogenic function and calcium deposits. The diabetic rat model receive titanium rod implantation was set up successfully and Von-Gieson staining was used to examine femoral bone tissue around titanium rod. Our results showed that intracellular oxidative stress in hyperglycemia was overexpressed, while FoxO1, SIRT1, GPX1, and SOD2 were downregulated. SIL suppressed oxidative stress to promote osteogenic differentiation. Additionally, it was confirmed that SIL promoted osteogenic differentiation of MC3T3-E1 and obviously restored the osseointegration ability of diabetic rats. Further study indicated that SIL exerted its beneficial function through activation SIRT1/SOD2 signaling pathway to restore osteoblast function, and improved the osseointegration and stability of titanium rods in vivo. Our research suggested that the SIL-modulated oxidative Stress inhibition is responsible for the activation of the process of osteogenic differentiation through activation SIRT1/SOD2 signaling pathway in hyperglycemia, providing a novel insight into improving prosthetic osseointegration in diabetic patients. Hyperglycemia impaired the activity and function of MC3T3-E1 and inhibits bone formation by up-regulating intracellular ROS levels through inhibition of SIRT1/SOD2 signaling pathway. Local administrator SIL can improve the activity and function of osteoblasts and enhance osseointegration by reducing intracellular ROS through activation of SIRT1/SOD2 signaling pathway in DM rat models.

Silk sericin patches delivering miRNA-29-enriched extracellular vesicles-decorated myoblasts (SPEED) enhances regeneration and functional repair after severe skeletal muscle injury

Severe skeletal muscle injuries usually lead to a series of poor recovery issues, such as massive myofibers loss, scar tissue formation, significant muscle function impairment, etc. Here, a silk sericin patch delivering miRNA-29-enriched extracellular vesicles-decorated myoblasts (SPEED) is designed for the rapid regeneration and functional repair after severe skeletal muscle injury. Specifically, miR29-enriched extracellular vesicles (miR29-EVs) are prepared and used to deliver miR29 into primary myoblasts, which promote the myotube formation of myoblasts and increase the expression of myogenic genes while inhibiting the expression of fibrotic genes. Our results indicate that miR29-EVs promote the integration of primary myoblasts and host muscle in a severe mouse tibialis anterior (TA) muscle injury model. Moreover, implantation of SPEED drastically stimulates skeletal muscle regeneration, inhibits fibrosis of injured muscles, and leads to significant improvement of muscle contraction forces and motor ability of mice about 3 weeks after treatment. Subsequently, we further evaluate the transcriptomes of TA muscles and find that SPEED can significantly ameliorate energy metabolism and muscular microenvironment of TA muscles on day 9 after implantation. Additionally, bioinformatic analysis and comprehensive molecular biology studies also reveal that the down-regulation of CDC20-MEF2C signaling axis may participate in the muscle repair process. Together, SPEED may serve as an effective alternative for the rapid repair of severe skeletal muscle injuries in the future.

The microRNA-29 family - role in metabolism and metabolic disease

The microRNA-29a family members miR-29a-3p, miR-29b-3p and miR-29c-3p are ubiquitously expressed and consistently increased in various tissues and cell types in conditions of metabolic disease; obesity, insulin resistance and type 2 diabetes. In pancreatic beta cells, miR-29a is required for normal exocytosis, but increased levels are associated with impaired beta cell function. Similarly, in liver miR-29 species are higher in models of insulin resistance and type 2 diabetes, and either knock-out or depletion using a microRNA inhibitor improves hepatic insulin resistance. In skeletal muscle, miR-29 upregulation is associated with insulin resistance and altered substrate oxidation, and similarly, in adipocytes over-expression of miR-29a leads to insulin resistance. Blocking miR-29a using nucleic acid antisense therapeutics show promising results in preclinical animal models of obesity and type 2 diabetes, although the widespread expression pattern of miR-29 family members complicates the exploration of single target tissues. However, in fibrotic diseases, such as in late complications of diabetes and metabolic disease (diabetic kidney disease, non-alcoholic steatohepatitis), miR-29 expression is suppressed by TGFβ allowing increased extracellular matrix collagen to form. In the clinical setting circulating levels of miR-29a and miR-29b are consistently increased in type 2 diabetes and in gestational diabetes, and are also possible prognostic markers for deterioration of glucose tolerance. In conclusion, miR-29 plays an essential role in various organs relevant to intermediary metabolism and its upregulation contribute to impaired glucose metabolism, while it suppresses fibrosis development. Thus, a correct balance of miR-29a levels seems important for cellular and organ homeostasis in metabolism.

CircRIMKLB promotes myoblast proliferation and inhibits differentiation by sponging miR-29c to release KCNJ12

Muscle development is a complex process that was regulated by many factors, among which non-coding RNAs (ncRNAs) play a vital role in regulating multiple life activities of muscle cells. Circular RNA (circRNA), a type of non-coding RNA with closed-loop structure, has been reported to affect multiple life processes. However, the roles of circRNAs on muscle development have not been fully elucidated. The present study aimed to determine whether and how circRIMKLB affects muscle development. Our study revealed that circRIMKLB promoted myoblast proliferation and inhibited differentiation. Besides, miR-29c was proved as a downstream target of circRIMKLB using dual-luciferase reporter assay and RNA-binding protein immunoprecipitation (RIP) assay. Also, potassium inwardly rectifying channel subfamily J member 12 (KCNJ12) was identified as a novel target of miR-29c via dual-luciferase reporter assay, quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR), and western blot. CircRIMKLB and KCNJ12 were both proved to regulate cell cycle on muscle regeneration after injury in vivo. In conclusion, we demonstrated that circRIMKLB sponged miR-29c, releasing KCNJ12 to regulate myoblast proliferation and differentiation and regulating cell cycle during muscle regeneration after injury in vivo.

Autophagy-Related Activation of Hepatic Stellate Cells Reduces Cellular miR-29a by Promoting Its Vesicular Secretion

BACKGROUND & AIMS

Liver fibrosis arises from long-term chronic liver injury, accompanied by an accelerated wound healing response with interstitial accumulation of extracellular matrix (ECM). Activated hepatic stellate cells (HSC) are the main source for ECM production. MicroRNA29a (miR-29a) is a crucial antifibrotic miRNA that is repressed during fibrosis, resulting in up-regulation of collagen synthesis.

METHODS

Intracellular and extracellular miRNA levels of primary and immortalized myofibroblastic HSC in response to profibrogenic stimulation by transforming growth factor β (TGFβ) or platelet-derived growth factor-BB (PDGF-BB) or upon inhibition of vesicular transport and autophagy processes were determined by quantitative polymerase chain reaction. Autophagy flux was studied by electron microscopy, flow cytometry, immunoblotting, and immunocytochemistry. Hepatic and serum miR-29a levels were quantified by using both liver tissue and serum samples from a cohort of chronic hepatitis C virus patients and a murine CCl4 induced liver fibrosis model.

RESULTS

In our study, we show that TGFβ and PDGF-BB resulted in decrease of intracellular miR-29a and a pronounced increase of vesicular miR-29a release into the supernatant. Strikingly, miR-29a vesicular release was accompanied by enhanced autophagic activity and up-regulation of the autophagy marker protein LC3. Moreover, autophagy inhibition strongly prevented miR-29a secretion and repressed its targets' expression such as Col1A1. Consistently, hepatic miR-29a loss and increased LC3 expression in myofibroblastic HSC were associated with increased serum miR-29a levels in CCl4-treated murine liver fibrosis and specimens of hepatitis C virus patients with chronic liver disease.

CONCLUSIONS

We provide evidence that activation-associated autophagy in HSC induces release of miR-29a, whereas inhibition of autophagy represses fibrogenic gene expression in part through attenuated miR-29a secretion.

Simultaneous disruption of circulating miR-21 and cytotoxic T lymphocytes (CTLs): Prospective diagnostic and prognostic markers for esophageal squamous cell carcinoma (ESCC)

BACKGROUND

Esophageal squamous cell carcinoma (ESCC) as the most prominent type of esophageal cancer (EC) in developing countries encompasses a substantial contribution of cancer-related mortalities and morbidities. Cytotoxic T lymphocytes (CTLs) are the major subset of effector T cells against cancer. However, the microRNAs involved in the development and regulation of CTLs could be disrupted in cancers such as EC.

METHODS

Here, we evaluated the population of IL-10, TGF-β, IFN-γ, and IL-17a-producing CD3+CD8+ T cells, their association with the circulating levels of miR-21 and miR-29b, and their diagnostic and/or prognostic (after 160 weeks of follow-up) utilities in 34 ESCC patients (12 newly diagnosed: ND, 24 under-treatment: UT) and 34 matched healthy donors.

RESULTS

The population of IL-10 and TGF-β-producing CTLs (CD8+ Tregs) were considerably expanded, in addition to the overexpression of miR-21 in both groups (ND and UT) of ESCC patients, while the frequency of Tc17 and CD8+ Treg cells increased only in UT patients. The expression means of TGF-β and IL-10 in CTLs were considered to be excellent biomarkers (1 ≥ area under the curve: AUC ≥0.9) in distinguishing ESCC patients and associated subgroups from healthy subjects. Moreover, the lower expressions of TGF-β, IL-17a, IL-10, and IFN-γ in CTLs were associated with ESCC better prognosis.

CONCLUSIONS

The association between the impaired function of CD3+ CD8+ T cell subsets and miR-21 expression could be introduced as novel therapeutic targets and powerful diagnostic and prognostic markers for ESCC.

MicroRNAs in peripheral artery disease: potential biomarkers and pathophysiological mechanisms

Peripheral artery disease (PAD) is a disease of atherosclerosis in the lower extremities. PAD carries a massive burden worldwide, while diagnosis and treatment options are often lacking. One of the key points of research in recent years is the involvement of microRNAs (miRNAs), which are short 20-25 nucleotide single-stranded RNAs that can act as negative regulators of post-transcriptional gene expression. Many of these miRNAs have been discovered to be misregulated in PAD patients, suggesting a potential utility as biomarkers for PAD diagnosis. miRNAs have also been shown to play an important role in many different pathophysiological aspects involved in the initiation and progression of the disease including angiogenesis, hypoxia, inflammation, as well as other cellular functions like cell proliferation and migration. The research on miRNAs in PAD has the potential to lead to a whole new class of diagnostic tools and treatments.

Circular RNA circUSP13 sponges miR-29c to promote differentiation and inhibit apoptosis of goat myoblasts by targeting IGF1

Circular RNAs (circRNAs) are an indispensable element of post-transcriptional gene regulation, influencing a variety of biological processes including myogenic differentiation; however, little is known about the function of circRNA in goat myogenic differentiation. Using RNA-sequencing data from our laboratory, we explored the influences of circUSP13, as a candidate circRNA, on myoblast differentiation since its expression is higher in myoblasts of lamb (first day of age) than that of the fetus (75th day of pregnancy). In in vitro experiments, circUSP13 significantly promoted differentiation and inhibited apoptosis in goat primary myoblasts. Mechanistically, circUSP13 localized with miR-29c in the cytoplasm of goat myoblasts to regulate IGF1 expression. We further demonstrated that circUSP13 sponges miR-29c, promoting IGF1 expression that upregulated the expression of MyoG and MyHC. Thus, our results identified circUSP13 as a molecular marker for breeding programs of mutton production, as well as the circUSP13-miR-29c-IGF1 axis as a potential therapeutic target for combating muscle wasting.

MicroRNAs in Hypertrophic, Arrhythmogenic and Dilated Cardiomyopathy

MicroRNAs (miRNAs) are a class of non-coding RNAs of about 20 nucleotides in length, involved in the regulation of many biochemical pathways in the human body. The level of miRNAs in tissues and circulation can be deregulated because of altered pathophysiological mechanisms; thus, they can be employed as biomarkers for different pathological conditions, such as cardiac diseases. This review summarizes published findings of these molecular biomarkers in the three most common structural cardiomyopathies: human dilated, arrhythmogenic and hypertrophic cardiomyopathy.

Higher glucose availability augments the metabolic responses of the C2C12 myotubes to exercise-like electrical pulse stimulation

The application of exercise-like electrical pulse simulation (EL-EPS) has become a widely used exercise mimetic in vitro. EL-EPS produces similar physiological responses as in vivo exercise, while less is known about the detailed metabolic effects. Routinely, the C2C12 myotubes are cultured in high-glucose medium (4.5 g/L), which may alter EL-EPS responses. In this study, we evaluate the metabolic effects of EL-EPS under the high- and low-glucose (1.0 g/L) conditions to understand how substrate availability affects the myotube response to EL-EPS. The C2C12 myotube, media, and cell-free media metabolites were analyzed using untargeted nuclear magnetic resonance (NMR)-based metabolomics. Furthermore, translational and metabolic changes and possible exerkine effects were analyzed. EL-EPS enhanced substrate utilization as well as production and secretion of lactate, acetate, 3-hydroxybutyrate, and branched-chain fatty acids (BCFAs). The increase in BCFAs correlated with branched-chain amino acids (BCAAs) and BCFAs were strongly decreased when myotubes were cultured without BCAAs suggesting the action of acyl-CoA thioesterases on BCAA catabolites. Notably, not all EL-EPS responses were augmented by high glucose because EL-EPS increased phosphorylated c-Jun N-terminal kinase and interleukin-6 secretion independent of glucose availability. Administration of acetate and EL-EPS conditioned media on HepG2 hepatocytes had no adverse effects on lipolysis or triacylglycerol content. Our results demonstrate that unlike in cell-free media, the C2C12 myotube and media metabolites were affected by EL-EPS, particularly under high-glucose condition suggesting that media composition should be considered in future EL-EPS studies. Furthermore, acetate and BCFAs were identified as putative exerkines warranting more research.NEW & NOTEWORTHY The present study examined for the first time the metabolome of 1) C2C12 myotubes, 2) their growth media, and 3) cell-free media after exercise-like electrical pulse stimulation under distinct nutritional loads. We report that myotubes grown under high-glucose conditions had greater responsiveness to EL-EPS when compared with lower glucose availability conditions and increased media content of acetate and branched-chain fatty acids suggests they might act as putative exerkines warranting further research.

MiR-29ab1 Cluster Resists Muscle Atrophy Through Inhibiting MuRF1

Skeletal muscle has great plasticity. An increase in protein degradation can cause muscle atrophy. Atrogin-1 and muscle ring finger-1 (MuRF1) are dramatically upregulated in various muscle atrophy. Inhibition of Atrogin-1 and MuRF1 protects against muscle atrophy. MiR-29 plays an important regulatory role in skeletal muscle development. However, the function of miR-29 in skeletal muscle protein metabolism is not clear. To investigate the function of miR-29, we generated miR-29 knockout mice and the miR-29ab1 cluster overexpression mice. The disruption of miR-29 led to severe atrophy of skeletal muscle during puberty, and the muscle-specific overexpression of the miR-29ab1 cluster protected against denervation-induced and fasting-induced muscle atrophy. Furthermore, the overexpression of miR-29a, b mimics in myotubes resisted the muscle atrophy. MuRF1 was the direct target gene of miR-29a, b. These results demonstrate that miR-29ab1 cluster plays a critical role in the maintenance of skeletal muscle. MiR-29ab1 cluster is the excellent inhibitor of MuRF1, ultimately indicating that miR-29ab1 cluster is good therapeutic molecule candidate for adulthood.

Mirna Expression in Glaucomatous and TGFβ2 Treated Lamina Cribrosa Cells

Glaucoma is a group of optic neuropathies that leads to irreversible vision loss. The optic nerve head (ONH) is the site of initial optic nerve damage in glaucoma. ONH-derived lamina cribrosa (LC) cells synthesize extracellular matrix (ECM) proteins; however, these cells are adversely affected in glaucoma and cause detrimental changes to the ONH. LC cells respond to mechanical strain by increasing the profibrotic cytokine transforming growth factor-beta 2 (TGFβ2) and ECM proteins. Moreover, microRNAs (miRNAs or miR) regulate ECM gene expression in different fibrotic diseases, including glaucoma. A delicate homeostatic balance between profibrotic and anti-fibrotic miRNAs may contribute to the remodeling of ONH. This study aimed to determine whether modulation of miRNAs alters the expression of ECM in human LC cells. Primary human normal and glaucoma LC cells were grown to confluency and treated with or without TGFβ2 for 24 h. Differences in expression of miRNAs were analyzed using miRNA qPCR arrays. miRNA PCR arrays showed that the miR-29 family was significantly decreased in glaucomatous LC cell strains compared to age-matched controls. TGFβ2 treatment downregulated the expression of multiple miRNAs, including miR-29c-3p, compared to controls in LC cells. LC cells transfected with miR-29c-3p mimics or inhibitors modulated collagen expression.

Cell-Free Biological Approach for Corneal Stromal Wound Healing

Corneal opacification is the fourth most common cause of blindness globally behind cataracts, glaucoma, and age-related macular degeneration. The standard treatment of serious corneal scarring is corneal transplantation. Though it is effective for restoring vision, the treatment outcome is not optimal, due to limitations such as long-term graft survival, lifelong use of immunosuppressants, and a loss of corneal strength. Regulation of corneal stromal wound healing, along with inhibition or downregulation of corneal scarring is a promising approach to prevent corneal opacification. Pharmacological approaches have been suggested, however these are fraught with side effects. Tissue healing is an intricate process that involves cell death, proliferation, differentiation, and remodeling of the extracellular matrix. Current research on stromal wound healing is focused on corneal characteristics such as the immune response, angiogenesis, and cell signaling. Indeed, promising new technologies with the potential to modulate wound healing are under development. In this review, we provide an overview of cell-free strategies and some approaches under development that have the potential to control stromal fibrosis and scarring, especially in the context of early intervention.

Implications the Role of miR-155 in the Pathogenesis of Autoimmune Diseases

MicroRNAs (miRNAs) are small noncoding conserved RNAs containing 19 to 24 nucleotides that are regulators of post-translational modifications and are involved in the majority of biological processes such as immune homeostasis, T helper cell differentiation, central and peripheral tolerance, and immune cell development. Autoimmune diseases are characterized by immune system dysregulation, which ultimately leads to destructive responses to self-antigens. A large body of literature suggests that autoimmune diseases and immune dysregulation are associated with different miRNA expression changes in the target cells and tissues of adaptive or innate immunity. miR-155 is identified as a critical modulator of immune responses. Recently conducted studies on the expression profile of miR-155 suggest that the altered expression and function of miR-155 can mediate vulnerability to autoimmune diseases and cause significant dysfunction of the immune system.

Targeting lncRNA H19/miR-29b/COL1A1 Axis Impedes Myofibroblast Activities of Precancerous Oral Submucous Fibrosis

Oral submucous fibrosis (OSF) is known as a potentially malignant disorder, which may result from chemical irritation due to areca nuts (such as arecoline). Emerging evidence suggests that fibrogenesis and carcinogenesis are regulated by the interaction of long noncoding RNAs (lncRNAs) and microRNAs. Among these regulators, profibrotic lncRNA H19 has been found to be overexpressed in several fibrosis diseases. Here, we examined the expression of H19 in OSF specimens and its functional role in fibrotic buccal mucosal fibroblasts (fBMFs). Our results indicate that the aberrantly overexpressed H19 contributed to higher myofibroblast activities, such as collagen gel contractility and migration ability. We also demonstrated that H19 interacted with miR-29b, which suppressed the direct binding of miR-29b to the 3′-untranslated region of type I collagen (COL1A1). We showed that ectopic expression of miR-29b ameliorated various myofibroblast phenotypes and the expression of α-smooth muscle actin (α-SMA), COL1A1, and fibronectin (FN1) in fBMFs. In OSF tissues, we found that the expression of miR-29b was downregulated and there was a negative correlation between miR-29b and these fibrosis markers. Lastly, we demonstrate that arecoline stimulated the upregulation of H19 through the transforming growth factor (TGF)-β pathway. Altogether, this study suggests that increased TGF-β secretion following areca nut chewing may induce the upregulation of H19, which serves as a natural sponge for miR-29b and impedes its antifibrotic effects.

Epigenetics-based therapeutics for myocardial fibrosis

Myocardial fibrosis (MF) is a reactive remodeling process in response to myocardial injury. It is mainly manifested by the proliferation of cardiac muscle fibroblasts and secreting extracellular matrix (ECM) proteins to replace damaged tissue. However, the excessive production and deposition of extracellular matrix, and the rising proportion of type I and type III collagen lead to pathological fibrotic remodeling, thereby facilitating the development of cardiac dysfunction and eventually causing heart failure with heightened mortality. Currently, the molecular mechanisms of MF are still not fully understood. With the development of epigenetics, it is found that epigenetics controls the transcription of pro-fibrotic genes in MF by DNA methylation, histone modification and noncoding RNAs. In this review, we summarize and discuss the research progress of the mechanisms underlying MF from the perspective of epigenetics, including the newest m6A modification and crosstalk between different epigenetics in MF. We also offer a succinct overview of promising molecules targeting epigenetic regulators, which may provide novel therapeutic strategies against MF.

MicroRNAs in Skeletal Muscle and Hints on Their Potential Role in Muscle Wasting During Cancer Cachexia

Cancer-associated cachexia is a heterogeneous, multifactorial syndrome characterized by systemic inflammation, unintentional weight loss, and profound alteration in body composition. The main feature of cancer cachexia is represented by the loss of skeletal muscle tissue, which may or may not be accompanied by significant adipose tissue wasting. Such phenotypic alteration occurs as the result of concomitant increased myofibril breakdown and reduced muscle protein synthesis, actively contributing to fatigue, worsening of quality of life, and refractoriness to chemotherapy. According to the classical view, this condition is primarily triggered by interactions between specific tumor-induced pro-inflammatory cytokines and their cognate receptors expressed on the myocyte membrane. This causes a shift in gene expression of muscle cells, eventually leading to a pronounced catabolic condition and cell death. More recent studies, however, have shown the involvement of regulatory non-coding RNAs in the outbreak of cancer cachexia. In particular, the role exerted by microRNAs is being widely addressed, and several mechanistic studies are in progress. In this review, we discuss the most recent findings concerning the role of microRNAs in triggering or exacerbating muscle wasting in cancer cachexia, while mentioning about possible roles played by long non-coding RNAs and ADAR-mediated miRNA modifications.

Factors inducing transdifferentiation of myoblasts into adipocytes

Fat infiltration in skeletal muscle is observed in several myopathies, is associated with muscular dysfunction, and is strongly correlated with insulin resistance, diabetes, obesity, and aging. In animal production, skeletal muscle fat (also known as intermuscular and intramuscular fat) is positively related to meat quality including tenderness, flavor, and juiciness. Thus, understanding the cell origin and regulation mechanism of skeletal muscle fat infiltration is important for developing therapies against human myopathies as well as for improving meat quality. Notably, age, sarcopenia, oxidative stress, injury, and regeneration can activate adipogenic differentiation potential in myoblasts and affect fat accumulation in skeletal muscle. In addition, several transcriptional and nutritional factors can directly induce transdifferentiation of myoblasts into adipocytes. In this review, we focused on the recent progress in understanding the muscle-to-adipocyte differentiation and summarized and discussed the genetic, nutritional, and physiological factors that can induce transdifferentiation of myoblasts into adipocytes. Moreover, the regulatory roles and mechanisms of these factors during the transdifferentiation process were also discussed.

hsa_circNFXL1_009 modulates apoptosis, proliferation, migration, and potassium channel activation in pulmonary hypertension

In this study, we explored the circular RNA (circRNA) profile in pulmonary arterial hypertension (PAH) patients caused by chronic obstructive pulmonary disease (COPD) and the effects of hsa_circNFXL1_009 on abnormal proliferation, apoptosis, and migration of human pulmonary arterial smooth muscle cells (hPASMCs) driven by hypoxia. Using microarrays, we screened the circRNA profile in whole-blood samples from three pairs of subjects and found 158 dysregulated circRNAs in patients with PAH-COPD. Quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) analysis further validated that hsa_circNFXL1_009 was dramatically downregulated with the highest area under a receiver operating characteristic curve (ROC) in 21 pairs of subjects. Consistently, exposure to hypoxia markedly reduced the hsa_circNFXL1_009 level in cultured hPASMCs. Delivery of exogenous hsa_circNFXL1_009 attenuated hypoxia-induced proliferation, apoptotic resistance, and migration of hPASMCs, as evidenced by immunocytochemistry, 5-ethynyl-2′-deoxyuridine incorporation, wound healing, and a TUNEL (terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end labeling) assay. A luciferase assay showed that hsa_circNFXL1_009 directly sponged hsa-miR-29b-2-5p (miR-29b) and positively regulated the expression of voltage-gated potassium (K⁺) channel subfamily B member 1 (KCNB1) at the mRNA level. Using patch-clamp electrophysiology, we proved that overexpression of hsa_circNFXL1_009 promoted a whole-cell K⁺ current in hPASMCs. Taken together, these studies identify hsa_circNFXL1_009 as a key regulator of PAH, and it may be used as a potential therapeutic target for the treatment of PAH.

Mechanisms of IGF-1-Mediated Regulation of Skeletal Muscle Hypertrophy and Atrophy

Insulin-like growth factor-1 (IGF-1) is a key growth factor that regulates both anabolic and catabolic pathways in skeletal muscle. IGF-1 increases skeletal muscle protein synthesis via PI3K/Akt/mTOR and PI3K/Akt/GSK3β pathways. PI3K/Akt can also inhibit FoxOs and suppress transcription of E3 ubiquitin ligases that regulate ubiquitin proteasome system (UPS)-mediated protein degradation. Autophagy is likely inhibited by IGF-1 via mTOR and FoxO signaling, although the contribution of autophagy regulation in IGF-1-mediated inhibition of skeletal muscle atrophy remains to be determined. Evidence has suggested that IGF-1/Akt can inhibit muscle atrophy-inducing cytokine and myostatin signaling via inhibition of the NF-κΒ and Smad pathways, respectively. Several miRNAs have been found to regulate IGF-1 signaling in skeletal muscle, and these miRs are likely regulated in different pathological conditions and contribute to the development of muscle atrophy. IGF-1 also potentiates skeletal muscle regeneration via activation of skeletal muscle stem (satellite) cells, which may contribute to muscle hypertrophy and/or inhibit atrophy. Importantly, IGF-1 levels and IGF-1R downstream signaling are suppressed in many chronic disease conditions and likely result in muscle atrophy via the combined effects of altered protein synthesis, UPS activity, autophagy, and muscle regeneration.

MicroRNA-mRNA Co-sequencing Identifies Transcriptional and Post-transcriptional Regulatory Networks Underlying Muscle Wasting in Cancer Cachexia

Cancer cachexia is a metabolic syndrome with alterations in gene regulatory networks that consequently lead to skeletal muscle wasting. Integrating microRNAs-mRNAs omics profiles offers an opportunity to understand transcriptional and post-transcriptional regulatory networks underlying muscle wasting. Here, we used RNA sequencing to simultaneously integrate and explore microRNAs and mRNAs expression profiles in the tibialis anterior (TA) muscles of the Lewis Lung Carcinoma (LLC) model of cancer cachexia. We found 1,008 mRNAs and 18 microRNAs differentially expressed in cachectic mice compared with controls. Although our transcriptomic analysis demonstrated a high heterogeneity in mRNA profiles of cachectic mice, we identified a reduced number of differentially expressed genes that were uniformly regulated within cachectic muscles. This set of uniformly regulated genes is associated with the extracellular matrix (ECM), proteolysis, and inflammatory response. We also used transcriptomic data to perform enrichment analysis of transcriptional factor binding sites in promoter sequences, which revealed activation of the atrophy-related transcription factors NF-κB, Stat3, AP-1, and FoxO. Furthermore, the integration of mRNA and microRNA expression profiles identified post-transcriptional regulation by microRNAs of genes involved in ECM organization, cell migration, transcription factors binding, ion transport, and the FoxO signaling pathway. Our integrative analysis of microRNA-mRNA co-profiles comprehensively characterized regulatory relationships of molecular pathways and revealed microRNAs targeting ECM-associated genes in cancer cachexia.

Wnt-11 as a Potential Prognostic Biomarker and Therapeutic Target in Colorectal Cancer

The expression of the secreted factor Wnt-11 is elevated in several types of cancer, including colorectal cancer, where it promotes cancer cell migration and invasion. Analysis of colorectal cancer gene expression databases associated WNT11 mRNA expression with increased likelihood of metastasis in a subset of patients. WNT11 expression was correlated with the expression of the Wnt receptors FZD6, RYK, and PTK7, and the combined expression of WNT11, FZD6 and RYK or PTK7 was associated with an increased risk of 5-year mortality rates. Immunohistochemical analysis of Wnt-11 in a cohort of 357 colorectal cancer patients found significantly higher Wnt-11 levels in tumors, compared with benign tissue. Elevated Wnt-11 levels occurred more frequently in rectal tumors than in colonic tumors and in tumors from women than men. In univariate analysis, increased Wnt-11 expression was also associated with tumor invasion and increased 5-year mortality. High Wnt-11 levels were not associated with high levels of nuclear β-catenin, suggesting Wnt-11 is not simply an indicator for activation of β-catenin-dependent signaling. Expression of Wnt-11 in colorectal cancer cell lines expressing low endogenous Wnt-11 inhibited β-catenin/Tcf activity and increased ATF2-dependent transcriptional activity. WNT11 gene silencing and antibody-mediated inhibition of Wnt-11 in colorectal cancer cell lines expressing high Wnt-11 reduced their capacity for invasion. Together, these observations suggest that Wnt-11 could be a potential target for the treatment of patients with invasive colorectal cancer.

Role of Transforming Growth Factor-β in Skeletal Muscle Fibrosis: A Review

Transforming growth factor-beta (TGF-β) isoforms are cytokines involved in a variety of cellular processes, including myofiber repair and regulation of connective tissue formation. Activation of the TGF-β pathway contributes to pathologic fibrosis in most organs. Here, we have focused on examining the evidence demonstrating the involvement of TGF-β in the fibrosis of skeletal muscle particularly. The TGF-β pathway plays a role in different skeletal muscle myopathies, and TGF-β signaling is highly induced in these diseases. In this review, we discuss different molecular mechanisms of TGF-β-mediated skeletal muscle fibrosis and highlight different TGF-β-targeted treatments that target these relevant pathways.

A therapeutic approach towards microRNA29 family in vascular diabetic complications: A boon or curse?

Diabetes Mellitus (DM) is one of the major metabolic disorders and its severity leads to death. Enhancement in hyperglycaemic conditions of DM gives rise to endothelial impairment in small and large blood vessels contributing towards microvascular and macrovascular complications respectively. The pathogenesis of diabetic complications is associated with interruption of various signal transduction pathways due to epigenetic modifications such as aberrant histone modifications, DNA methylation and expression of miRNAs along with the long non-coding RNAs (lncRNAs). Amongst these epigenetic alterations, modulated expressions of miRNAs confer to apoptosis and endothelial dysfunction of organs that gives rise to vascular complications. In this review, we principally focussed on physiological role of miR29 family in DM and have discussed crosstalk between miR29 family and numerous genes involved in signal transduction pathways of Diabetic vascular complications. Incidences of diabetic retinopathy exploiting the role of miR29 in regulation of EMT process, differential expression patterns of miR29 and promising therapeutic role of miR29 have been discussed. We have summarised the therapeutic role of miR29 in podocyte impairment and how miR29 regulates the expressions of profibrotic, inflammatory and ECM encoding genes in renal fibrosis under diabetic conditions. We have also highlighted impact of miR29 expression patterns in cardiac angiopathy, cardiomyocyte's apoptosis and cardiac fibrosis. Additionally, we have also presented the contradictory actions of miR29 family in amelioration as well as in enhancement of diabetic complications.

YY1 regulates skeletal muscle regeneration through controlling metabolic reprogramming of satellite cells

Skeletal muscle satellite cells (SCs) are adult muscle stem cells responsible for muscle regeneration after acute or chronic injuries. The lineage progression of quiescent SC toward activation, proliferation, and differentiation during the regeneration is orchestrated by cascades of transcription factors (TFs). Here, we elucidate the function of TF Yin Yang1 (YY1) in muscle regeneration. Muscle-specific deletion of YY1 in embryonic muscle progenitors leads to severe deformity of diaphragm muscle formation, thus neonatal death. Inducible deletion of YY1 in SC almost completely blocks the acute damage-induced muscle repair and exacerbates the chronic injury-induced dystrophic phenotype. Examination of SC revealed that YY1 loss results in cell-autonomous defect in activation and proliferation. Mechanistic search revealed that YY1 binds and represses mitochondrial gene expression. Simultaneously, it also stabilizes Hif1α protein and activates Hif1α-mediated glycolytic genes to facilitate a metabolic reprogramming toward glycolysis which is needed for SC proliferation. Altogether, our findings have identified YY1 as a key regulator of SC metabolic reprogramming through its dual roles in modulating both mitochondrial and glycolytic pathways.

Identification of miR-29c and its Target FBXO31 as a Key Regulatory Mechanism in Esophageal Cancer Chemoresistance: Functional Validation and Clinical Significance

Rationale: Dysregulated microRNA (miRNA) expressions in cancer can contribute to chemoresistance. This study aims to identify miRNAs that are associated with fluorouracil (5-FU) chemoresistance in esophageal squamous cell carcinoma (ESCC). The potential of miR-29c as a novel diagnostic, prognostic and treatment-predictive marker in ESCC, and its mechanisms and therapeutic implication in overcoming 5-FU chemoresistance were explored. Methods: The miRNA profiles of an ESCC cell model with acquired chemoresistance to 5-FU were analyzed using a Taqman miRNA microarray to identify novel miRNAs associated with 5-FU chemoresistance. Quantitative real-time PCR was used to determine miR-29c expression in tissue and serum samples of patients. Bioinformatics, gain- and loss-of-function experiments, and luciferase reporter assay were performed to validate F-box only protein 31 (FBXO31) as a direct target of miR-29c, and to identify potential transcription factor binding events that control miR-29c expression. The potential of systemic miR-29c oligonucleotide-based therapy in overcoming 5-FU chemoresistance was evaluated in tumor xenograft model. Results: MiR-29c, under the regulatory control of STAT5A, was frequently downregulated in tumor and serum samples of patients with ESCC, and the expression level was correlated with overall survival. Functional studies showed that miR-29c could override 5-FU chemoresistance in vitro and in vivo by directly interacting with the 3'UTR of FBXO31, leading to repression of FBXO31 expression and downstream activation of p38 MAPK. Systemically administered miR-29c dramatically improved response of 5-FU chemoresistant ESCC xenografts in vivo. Conclusions: MiR-29c modulates chemoresistance by interacting with FBXO31, and is a promising non-invasive biomarker and therapeutic target in ESCC.

Concordant miRNA and mRNA expression profiles in humans and mice with bladder outlet obstruction

Bladder outlet obstruction (BOO) leads to lower urinary tract symptoms (LUTS) and urodynamic changes of the bladder function. Previously we identified microRNA (miRNA) and mRNA expression profiles associated with different states of BOO-induced LUTD in human patients. Bladder wall remodeling resulting from obstruction is widely studied in animal models of experimentally-induced partial BOO (pBOO). Here we determined the expression profiles of miRNAs and selected mRNAs in pBOO mice and compared the observed changes to human patients. Similar to results from human patients, we observed a down-regulation of smooth muscle-associated miRNAs mmu-miR-1, mmu-miR-143, mmu-miR-145, mmu-miR-486 and mmu-miR-133a in pBOO mouse bladders. Pro-fibrotic miRNAs mmu-miR-142-3p and mmu-miR-21 were up-regulated, and anti-fibrotic miRNA mmu-miR-29c was down-regulated. Pathway analysis in human BOO patients identified TNF-alpha as the top upstream regulator. Although there was evidence of hypertrophic changes in pBOO mice, contrary to human data, we observed no regulation of TNF-responsive genes in the mouse model. Experimentally-induced pBOO in mice led to significant gene expression changes, including alteration of pro-fibrotic mRNAs and miRNAs resembling human BOO patients. Gene expression changes were also validated in a mouse model of bladder inflammation. Lack of evidence of TNF-alpha-induced miRNA and mRNA regulation might indicate a different pathophysiological mechanism of organ remodeling in pBOO model compared to the human disease.

miR29b regulates aberrant methylation in In-Vitro diabetic nephropathy model of renal proximal tubular cells

The role of DNA methylation has not been enough explored in pathophysiology of diabetic nephropathy (DN). However, according to recent reports it has been inferred that hypermethylation could be one of the principle cause associated with the enhancement of DN. An interrelationship between miR29b and DNA methylation has been studied via in-silico analysis. We have validated that miR29b prominently targets DNA methyl transferase (DNMT), specifically DNMT1, DNMT3A and DNMT3B. We have developed in vitro DN model using renal proximal tubule epithelial cells (RPTECs), contributed to a significant alleviation in RNA and protein expression levels of DNMT3A, DNMT3B and DNMT1. The developed model has also demonstrated downregulation in expression of miR29b. Our studies have also suggested that miR29b targets DNMT1 via targeting its transcription factor SP1. In addition to this, downregulation of a specific biomarker for kidney injury, tubular kidney injury molecule-1 (KIM-1) and fibrosis causing glycoprotein i.e. fibronectin, was also demonstrated. Hence, the developed model revealed that hypermethylation is a key factor incorporated in DN, and miR29b could effectively ameliorate defensive actions in DN pathogenesis.

A Novel Circular RNA Generated by FGFR2 Gene Promotes Myoblast Proliferation and Differentiation by Sponging miR-133a-5p and miR-29b-1-5p

It is well known that fibroblast growth factor receptor 2 (FGFR2) interacts with its ligand of fibroblast growth factor (FGF) therefore exerting biological functions on cell proliferation and differentiation. In this study, we first reported that the FGFR2 gene could generate a circular RNA of circFGFR2, which regulates skeletal muscle development by sponging miRNA. In our previous study of circular RNA sequencing, we found that circFGFR2, generated by exon 3–6 of FGFR2 gene, differentially expressed during chicken embryo skeletal muscle development. The purpose of this study was to reveal the real mechanism of how circFGFR2 affects skeletal muscle development in chicken. In this study, cell proliferation was analyzed by both flow cytometry analysis of the cell cycle and 5-ethynyl-2′-deoxyuridine (EdU) assays. Cell differentiation was determined by analysis of the expression of the differentiation marker gene and Myosin heavy chain (MyHC) immunofluorescence. The results of flow cytometry analysis of the cell cycle and EdU assays showed that, overexpression of circFGFR2 accelerated the proliferation of myoblast and QM-7 cells, whereas knockdown of circFGFR2 with siRNA reduced the proliferation of both cells. Meanwhile, overexpression of circFGFR2 accelerated the expression of myogenic differentiation 1 (MYOD), myogenin (MYOG) and the formation of myotubes, and knockdown of circFGFR2 showed contrary effects in myoblasts. Results of luciferase reporter assay and biotin-coupled miRNA pull down assay further showed that circFGFR2 could directly target two binding sites of miR-133a-5p and one binding site of miR-29b-1-5p, and further inhibited the expression and activity of these two miRNAs. In addition, we demonstrated that both miR-133a-5p and miR-29b-1-5p inhibited myoblast proliferation and differentiation, while circFGFR2 could eliminate the inhibition effects of the two miRNAs as indicated by rescue experiments. Altogether, our data revealed that a novel circular RNA of circFGFR2 could promote skeletal muscle proliferation and differentiation by sponging miR-133a-5p and miR-29b-1-5p.

Formoterol treatment prevents the effects of endotoxin on muscle TNF/NF-kB, Akt/mTOR, and proteolytic pathways in a rat model. Role of IGF-I and miRNA 29b

Inflammatory diseases are associated with muscle wasting as a result of an increase in proteolysis. The purpose of this study was to elucidate whether administration of a β2 adrenergic agonist, formoterol, was able to prevent the acute effects of sepsis induced by liposaccharide (LPS) injection on rat gastrocnemius muscle and to evaluate the possible roles of corticosterone, IGF-I, miR-23a, and miR-29b. For this purpose, male Wistar rats were injected with LPS and/or formoterol. Formoterol treatment decreased LPS-induced increase in serum corticosterone, TNFα upregulation, and NF-κB(p65) and Forkhead box protein O1 activation in the gastrocnemius. Atrogin-1, muscle RING-finger protein-1, microtubule-associated protein-1 light chain 3b (LC3b), and the lipidation of LC3b-I to LC3b-II were increased by LPS, and formoterol blocked these effects. Serum IGF-I and its mRNA levels in the gastrocnemius were decreased, whereas mecano growth factor and IGF binding protein 3 mRNA levels were increased in the rats injected with LPS but not in the rats that received LPS and formoterol. Similarly, LPS decreased Akt and mammalian target of rapamycin phosphorylation, and formoterol blocked these decreases. Finally, miR-29b expression in the gastrocnemius was upregulated by endotoxin injection, whereas miR-23a was not significantly different. Formoterol treatment did not significantly modify LPS-induced increase in muscle miR-29b. Furthermore, in control rats formoterol increased the expression of this miRNA. We conclude that formoterol decreases endotoxin-induced inflammation and proteolysis in rat skeletal muscle. Those responses can be a direct effect of β2 adrenergic receptor stimulation or/and of blocking the effects of LPS on corticosterone and IGF-I. Muscle miR-23a and -29b do not seem to play an important role in those responses.

Non-coding RNAs in aneurysmal aortopathy

Aortic aneurysms represent a major public health burden, and currently have no medical treatment options. The pathophysiology behind these aneurysms is complex and variable, depending on location and underlying cause, and generally involves progressive dysfunction of all elements of the aortic wall. Changes in smooth muscle behavior, endothelial signaling, extracellular matrix remodeling, and to a variable extent inflammatory signaling and cells, all contribute to the dilation of the aorta, ultimately resulting in high mortality and morbidity events including dissection and rupture. A large number of researchers have identified non-coding RNAs as crucial regulators of aortic aneurysm development, both in humans and in animal models. While most work to-date has focused on microRNAs, intriguing information has also begun to emerge regarding the role of long-non-coding RNAs. This review summarizes the currently available data regarding the involvement of non-coding RNAs in aneurysmal aortopathies. Going forward, these represent key potential therapeutic targets that might be leveraged in the future to slow or prevent aortic aneurysm formation, progression and rupture.

Molecular study of wound healing after using biosynthesized BNC/Fe3O4 nanocomposites assisted with a bioinformatics approach

Background

Molecular investigation of wound healing has allowed better understanding about interaction of genes and pathways involved in healing progression.

Objectives

The aim of this study was to prepare magnetic/bacterial nanocellulose (Fe₃O₄/BNC) nanocomposite films as ecofriendly wound dressing in order to evaluate their physical, cytotoxicity and antimicrobial properties. The molecular study was carried out to evaluate expression of genes involved in healing of wounds after treatment with BNC/Fe₃O₄ films.

Study design, materials, and methods

Magnetic nanoparticles were biosynthesized by using Aloe vera extract in new isolated bacterial nanocellulose (BNC) RM1. The nanocomposites were characterized using X-ray diffraction, Fourier transform infrared, and field emission scanning electron microscopy. Moreover, swelling property and metal ions release profile of the nanocomposites were investigated. The ability of nanocomposites to promote wound healing of human dermal fibroblast cells in vitro was examined. Bioinformatics databases were used to identify genes with important healing effect. Key genes which interfered with healing were studied by quantitative real time PCR.

Results

Spherical magnetic nanoparticles (15–30 nm) were formed and immobilized within the structure of BNC. The BNC/Fe₃O₄ was nontoxic (IC₅₀>500 μg/mL) with excellent wound healing efficiency after 48 hours. The nanocomposites showed good antibacterial activity ranging from 6±0.2 to 13.40±0.10 mm against Staphylococcus aureus, Staphylococcus epidermidis and Pseudomonas aeruginosa. The effective genes for the wound healing process were TGF-B1, MMP2, MMP9, Wnt4, CTNNB1, hsa-miR-29b, and hsa-miR-29c with time dependent manner. BNC/Fe₃O₄ has an effect on microRNA by reducing its expression and therefore causing an increase in the gene expression of other genes, which consequently resulted in wound healing.

Conclusion

This eco-friendly nanocomposite with excellent healing properties can be used as an effective wound dressing for treatment of cutaneous wounds.

Allele-specific differences in transcriptome, miRNome, and mitochondrial function in two hypertrophic cardiomyopathy mouse models

Hypertrophic cardiomyopathy (HCM) stems from mutations in sarcomeric proteins that elicit distinct biophysical sequelae, which in turn may yield radically different intracellular signaling and molecular pathologic profiles. These signaling events remain largely unaddressed by clinical trials that have selected patients based on clinical HCM diagnosis, irrespective of genotype. In this study, we determined how two mouse models of HCM differ, with respect to cellular/mitochondrial function and molecular biosignatures, at an early stage of disease. We show that hearts from young R92W-TnT and R403Q-αMyHC mutation-bearing mice differ in their transcriptome, miRNome, intracellular redox environment, mitochondrial antioxidant defense mechanisms, and susceptibility to mitochondrial permeability transition pore opening. Pathway analysis of mRNA-sequencing data and microRNA profiles indicate that R92W-TnT mutants exhibit a biosignature consistent with activation of profibrotic TGF-β signaling. Our results suggest that the oxidative environment and mitochondrial impairment in young R92W-TnT mice promote activation of TGF-β signaling that foreshadows a pernicious phenotype in young individuals. Of the two mutations, R92W-TnT is more likely to benefit from anti-TGF-β signaling effects conferred by angiotensin receptor blockers and may be responsive to mitochondrial antioxidant strategies in the early stage of disease. Molecular and functional profiling may therefore serve as aids to guide precision therapy for HCM.

Regulation of type I collagen expression by microRNA-29 following ionizing radiation

Radiation-induced fibrosis (RIF) is thought to involve the excessive accumulation of collagen and other extracellular matrix components; previously, we reported that ionizing radiation increased the type I collagen expression and that transforming growth factor (TGF)-β was involved in this increase through activating its downstream mediator, Smad3. A recent study found that microRNAs (miRNAs)-small, noncoding sequences approximately 20 nucleotides long-negatively regulate the gene expression posttranscriptionally, and it has been suggested that miRNAs play essential roles in cellular processes, including fibrosis. However, their role in the development of RIF remains unexplored. In the present study, we examined the effects of miRNA on the expression of type I collagen induced by ionizing radiation and the mechanisms underlying the miRNA expression observed following ionizing radiation. We analyzed the regulation of miRNA following ionizing radiation by an miRNA real-time PCR, and found that miR-29 family members were downregulated in irradiated mouse fibroblasts and directly targeted type I collagen genes by specifically binding to the 3' untranslated region. We also found that the overexpression of miR-29 inhibited the ionizing radiation-induced expression of type I collagen, whereas the knockdown of miR-29 enhanced it. In addition, TGF-β/Smad-signaling significantly decreased the transcription of miR-29, whereas the inhibition of this signaling pathway cancelled this decrease. In conclusion, miR-29 was involved in the regulation of type I collagen expression through the TGF-β/Smad-signaling pathway in irradiated cells, suggesting that miR-29 may be an important regulator of RIF.

The "dark matter" of DNA and the regulation of bone metabolism: The role of non-coding RNAs

Epigenetics, present a new discipline that attempts to explain significant differences in phenotypes among patients with the same disease. In contrast to the other epigenetic mechanisms that modulate gene transcription, non-coding RNAs act at the post-transcriptional level. They directly modulate the gene expression of mRNA genes leading to mRNA target cleavage and degradation and translation repression. Bioinformatic predictions indicate that non coding RNAs may be involved in the regulation of 60% of the coding genes and each non-coding RNA can have multiple target genes, and each gene may be regulated by more than one non-coding RNAs. In the last decade several studies have shown a significant role of non-coding RNAs in the regulation of bone metabolism and function of bone cells opening a new era in the understanding of bone biology in health and disease.

MicroRNA-29: A Crucial Player in Fibrotic Disease

Fibrosis is a common pathological state characterized by the excessive accumulation of extracellular matrix components, but the pathogenesis of the disease is still not clear. Previous studies have shown that microRNA-29 (miR-29) can play pivotal roles in the regulation of a variety of organ fibrosis, including cardiac fibrosis, hepatic fibrosis, lung fibrosis, systemic sclerosis, and keloid. In this review, we outline the structure, expression, and regulation of miR-29 as well as its role in fibrotic diseases.

Exosomal small RNA sequencing uncovers the microRNA dose markers for power frequency electromagnetic field exposure

PURPOSE

The potential health risks caused by power frequency electromagnetic field (PFEMF) have led to increase public health concerns. However, the diagnosis and prognosis remain challenging in determination of exact dose of PFEMF exposure.

MATERIALS AND METHODS

Mice were exposed to different magnetic doses of PFEMF for the following isolation of serum exosomes, microRNAs (miRNAs) extraction and small RNA sequencing. After small RNA sequencing, bioinformatic analysis, quantitative real-time PCR (qRT-PCR) validation and serum exosomal miRNA biomarkers were determined.

RESULTS

Significantly changed serum exosomal miRNA as biomarkers of 0.1, 0.5, 2.5 mT and common PFEMF exposure were confirmed. Gene ontology (GO) and Kyoto encyclopaedia of genes and genomes (KEGG) pathway analysis of the downstream target genes of the above-identified exosomal miRNA markers indicated that, exosomal miRNA markers were predicted to be involved in critical pathophysiological processes of neural system and cancer- or other disease-related signalling pathways.

CONCLUSIONS

Aberrantly-expressed serum exosomal miRNAs, including miR-128-3p for 0.1 mT, miR-133a-3p for 0.5 mT, miR-142a-5p for 2.5 mT, miR-218-5p and miR-199a-3p for common PFEMF exposure, suggested a series of informative markers for not only identifying the exact dose of PFEMF exposure, also consolidating the base for future clinical intervention.

MicroRNA-29c Prevents Pulmonary Fibrosis by Regulating Epithelial Cell Renewal and Apoptosis

Successful repair and renewal of alveolar epithelial cells (AECs) are critical in prohibiting the accumulation of myofibroblasts in pulmonary fibrogenesis. MicroRNAs (miRNAs) are multifocal regulators involved in lung injury and repair. However, the contribution of miRNAs to AEC2 renewal and apoptosis is incompletely understood. We report that miRNA-29c (miR-29c) expression is lower in AEC2s of individuals with idiopathic pulmonary fibrosis than in healthy lungs. Epithelial cells overexpressing miR-29c show higher proliferative rates and viability. miR-29c protects epithelial cells from apoptosis by targeting forkhead box O3a (Foxo3a). Both overexpression of miR-29c conventionally and AEC2s specifically lead to less fibrosis and better recovery in vivo. Furthermore, deficiency of miR-29c in AEC2s results in higher apoptosis and reduced epithelial renewal. Interestingly, a gene network including a subset of apoptotic genes was coregulated by both Toll-like receptor 4 and miR-29c. Taken together, miR-29c maintains epithelial integrity and promotes recovery from lung injury, thereby attenuating lung fibrosis in mice.

Integration of miRNA and mRNA expression profiles reveals microRNA-regulated networks during muscle wasting in cardiac cachexia

Cardiac cachexia (CC) is a common complication of heart failure (HF) associated with muscle wasting and poor patient prognosis. Although different mechanisms have been proposed to explain muscle wasting during CC, its pathogenesis is still not understood. Here, we described an integrative analysis between miRNA and mRNA expression profiles of muscle wasting during CC. Global gene expression profiling identified 1,281 genes and 19 miRNAs differentially expressed in muscle wasting during CC. Several of these deregulated genes are known or putative targets of the altered miRNAs, including miR-29a-3p, miR-29b-3p, miR-210-5p, miR-214, and miR-489. Gene ontology analysis on integrative mRNA/miRNA expression profiling data revealed miRNA interactions affecting genes that regulate extra-cellular matrix (ECM) organization, proteasome protein degradation, citric acid cycle and respiratory electron transport. We further identified 11 miRNAs, including miR-29a-3p and miR-29b-3p, which target 21 transcripts encoding the collagen proteins related to ECM organization. Integrative miRNA and mRNA global expression data allowed us to identify miRNA target genes involved in skeletal muscle wasting in CC. Our functional experiments in C2C12 cells confirmed that miR-29b down-regulates collagen genes and contributes to muscle cell atrophy. Collectively, our results suggest that key ECM-associated miRNAs and their target genes may contribute to CC in HF.

LncFunNet: an integrated computational framework for identification of functional long noncoding RNAs in mouse skeletal muscle cells

Long noncoding RNAs (lncRNAs) are key regulators of diverse cellular processes. Recent advances in high-throughput sequencing have allowed for an unprecedented discovery of novel lncRNAs. To identify functional lncRNAs from thousands of candidates for further functional validation is still a challenging task. Here, we present a novel computational framework, lncFunNet (lncRNA Functional inference through integrated Network) that integrates ChIP-seq, CLIP-seq and RNA-seq data to predict, prioritize and annotate lncRNA functions. In mouse embryonic stem cells (mESCs), using lncFunNet we not only recovered most of the functional lncRNAs known to maintain mESC pluripotency but also predicted a plethora of novel functional lncRNAs. Similarly, in mouse myoblast C2C12 cells, applying lncFunNet led to prediction of reservoirs of functional lncRNAs in both proliferating myoblasts (MBs) and differentiating myotubes (MTs). Further analyses demonstrated that these lncRNAs are frequently bound by key transcription factors, interact with miRNAs and constitute key nodes in biological network motifs. Further experimentations validated their dynamic expression profiles and functionality during myoblast differentiation. Collectively, our studies demonstrate the use of lncFunNet to annotate and identify functional lncRNAs in a given biological system.

microRNA in Cardiovascular Aging and Age-Related Cardiovascular Diseases

Over the last decades, life expectancy has significantly increased although several chronic diseases persist in the population, with aging as the leading risk factor. Despite improvements in diagnosis and treatment, many elderlies suffer from cardiovascular problems that are much more frequent in an older, more fragile organism. In the long term, age-related cardiovascular diseases (CVDs) contribute to the decline of quality of life and ability to perform normal activities of daily living. microRNAs (miRNAs) are a class of small non-coding RNAs that regulate gene expression at the posttranscriptional level in both physiological and pathological conditions. In this review, we will focus on the role of miRNAs in aging and age-related CVDs as heart failure, hypertension, atherosclerosis, atrial fibrillation, and diabetes mellitus. miRNAs are key regulators of complex biological mechanisms, representing an exciting potential therapeutic target in CVDs. Moreover, one major challenge in geriatric medicine is to find reliable biomarkers for diagnosis, prognosis, and prediction of the response to specific drugs. miRNAs represent a very promising tool due to their stability in the circulation and unique signature in CVDs. However, further studies are needed to investigate their translational potential in the real clinical practice.

The Roles of Long Non-Protein-Coding RNAs in Osteo-Adipogenic Lineage Commitment

Osteoblasts and adipocytes share a common mesenchymal progenitor in the bone marrow. This implies that a reciprocal relationship exists between osteogenic and adipogenic differentiation. Further, cells of osteoblast lineage transdifferentiate into adipocytes under some circumstances. Dysregulation of osteo-adipogenic fate-determination leads to bone diseases such as osteoporosis, accompanied by an increase in bone marrow adipose tissue. Thus, the fine-tuning of osteo-adipogenesis is necessary for bone homeostasis. Osteo-adipogenic progression is governed by a complex crosstalk of extrinsic signals, transcription factors, and epigenetic factors. Long non-protein-coding RNAs (lncRNAs) act in part as epigenetic regulators in a broad range of biological activities, such as chromatin organization, transcriptional regulation, post-translational modifications, and histone modification. In this review, we highlight the roles of epigenetic regulators, particularly lncRNAs, in the osteo-adipogenic lineage commitment of bone marrow mesenchymal stem cells and the adipogenic transdifferentiation of osteoblasts.