Downregulation of miR-133 via MAPK/ERK signaling pathway involved in nicotine-induced cardiomyocyte apoptosis

Traditional Therapeutics and Potential Epidrugs for CVD: Why Not Both?

Cardiovascular disease (CVD) is the leading cause of death worldwide. In addition to the high mortality rate, people suffering from CVD often endure difficulties with physical activities and productivity that significantly affect their quality of life. The high prevalence of debilitating risk factors such as obesity, type 2 diabetes mellitus, smoking, hypertension, and hyperlipidemia only predicts a bleak future. Current traditional CVD interventions offer temporary respite; however, they compound the severe economic strain of health-related expenditures. Furthermore, these therapeutics can be prescribed indefinitely. Recent advances in the field of epigenetics have generated new treatment options by confronting CVD at an epigenetic level. This involves modulating gene expression by altering the organization of our genome rather than altering the DNA sequence itself. Epigenetic changes are heritable, reversible, and influenced by environmental factors such as medications. As CVD is physiologically and pathologically diverse in nature, epigenetic interventions can offer a ray of hope to replace or be combined with traditional therapeutics to provide the prospect of addressing more than just the symptoms of CVD. This review discusses various risk factors contributing to CVD, perspectives of current traditional medications in practice, and a focus on potential epigenetic therapeutics to be used as alternatives.

Nicotine neurotoxicity exacerbation following engineered Ag and Cu (50-60 nm) nanoparticles intoxication. Neuroprotection with nanowired delivery of antioxidant compound H-290/51 together with serotonin 5-HT3 receptor antagonist ondansetron

Nicotine abuse is frequent worldwide leading to about 8 millions people die every year due to tobacco related diseases. Military personnel often use nicotine smoking that is about 12.8% higher than civilian populations. Nicotine smoking triggers oxidative stress and are linked to several neurodegenerative diseases such as Alzheimer's disease. Nicotine neurotoxicity induces significant depression and oxidative stress in the brain leading to neurovascular damages and brain pathology. Thus, details of nicotine neurotoxicity and factors influencing them require additional investigations. In this review, effects of engineered nanoparticles from metals Ag and Cu (50-60 nm) on nicotine neurotoxicity are discussed with regard to nicotine smoking. Military personnel often work in the environment where chances of nanoparticles exposure are quite common. In our earlier studies, we have shown that nanoparticles alone induces breakdown of the blood-brain barrier (BBB) and exacerbates brain pathology in animal models. In present investigation, nicotine exposure in with Ag or Cu nanoparticles intoxicated group exacerbated BBB breakdown, induce oxidative stress and aggravate brain pathology. Treatment with nanowired H-290/51 a potent chain-breaking antioxidant together with nanowired ondansetron, a potent 5-HT3 receptor antagonist significantly reduced oxidative stress, BBB breakdown and brain pathology in nicotine exposure associated with Ag or Cu nanoparticles intoxication. The functional significance of this findings and possible mechanisms of nicotine neurotoxicity are discussed based on current literature.

Exosomes: mediators regulating the phenotypic transition of vascular smooth muscle cells in atherosclerosis

Cardiovascular disease is one of the leading causes of human mortality worldwide, mainly due to atherosclerosis (AS), and the phenotypic transition of vascular smooth muscle cells (VSMCs) is a key event in the development of AS. Exosomes contain a variety of specific nucleic acids and proteins that mediate intercellular communication. The role of exosomes in AS has attracted attention. This review uses the VSMC phenotypic transition in AS as the entry point, introduces the effect of exosomes on AS from different perspectives, and discusses the status quo, deficiencies, and potential future directions in this field to provide new ideas for clinical research and treatment of AS. Video Abstract.

The Regulatory Role of H19/miR-181a/ATG5 Signaling in Perinatal Nicotine Exposure-Induced Development of Neonatal Brain Hypoxic-Ischemic Sensitive Phenotype

Nicotine exposure either from maternal cigarette smoking or e-cigarette vaping is one of the most common risk factors for neurodevelopmental disease in offspring. Previous studies revealed that perinatal nicotine exposure programs a sensitive phenotype to neonatal hypoxic-ischemic encephalopathy (HIE) in postnatal life, yet the underlying mechanisms remain undetermined. The goal of the present study was to determine the regulatory role of H19/miR-181a/ATG5 signaling in perinatal nicotine exposure-induced development of neonatal brain hypoxic-ischemic sensitive phenotype. Nicotine was administered to pregnant rats via subcutaneous osmotic minipumps. All experiments were conducted in offspring pups at postnatal day 9 (P9). Perinatal nicotine exposure significantly enhanced expression of miR-181a but attenuated autophagy-related protein 5 (ATG5) mRNA and protein levels in neonatal brains. Of interest, miR-181a mimicking administration in the absence of nicotine exposure also produced dose-dependent increased hypoxia/ischemia (H/I)-induced brain injury associated with a decreased ATG5 expression, closely resembling perinatal nicotine exposure-mediated effects. Locked nucleic acid (LNA)-miR-181a antisense reversed perinatal nicotine-mediated increase in H/I-induced brain injury and normalized aberrant ATG5 expression. In addition, nicotine exposure attenuated a long non-coding RNA (lncRNA) H19 expression level. Knockdown of H19 via siRNA increased the miR-181a level and enhanced H/I-induced neonatal brain injury. In conclusion, the present findings provide a novel mechanism that aberrant alteration of the H19/miR-181a/AGT5 axis plays a vital role in perinatal nicotine exposure-mediated ischemia-sensitive phenotype in offspring and suggests promising molecular targets for intervention and rescuing nicotine-induced adverse programming effects in offspring.

Exercise Training Attenuates Cardiac Vulnerability and Promotes Cardiac Resistance to Isoproterenol-Induced Injury Following Hookah Smoke Inhalation in Male Rats: Role of Klotho and Sirtuins

Hookah smoking is on the rise around the world. Present study investigated the heart resistance to harmful stress following long-term waterpipe tobacco smoking (WTS) and moderate-intensity exercise training intervention in male Wistar rats. Animals were randomly divided into a non-ischemic heart control group and four ischemic heart groups including ISO (isoproterenol-treated), Ex + ISO (subjected to exercise plus ISO), S + ISO (exposed to hookah smoke plus ISO), and Ex + S + ISO (subjected to exercise along with hookah smoke plus ISO). After eight weeks of training and WTS, heart ischemia induced by isoproterenol injections. Then, cardiac functional indices and some biochemical and histopathological parameters were assessed. WTS + ISO reduced systolic pressure, ± dP/dt max, and contractility indices (P < 0.001 vs. ISO group) and increased end diastolic pressure and Tau index (P < 0.001 vs. ISO) of the left ventricle. Also, WTS + ISO was associated with an increase in Bax protein level and Bax/Bcl-2 ratio (P < 0.05 and P < 001, respectively, vs. ISO group) as apoptotic markers of heart tissue. Hookah smoke significantly decreased SIRT1 (P < 0.05 and P < 0.001, respectively, vs. ISO) and klotho (P < 0.01 and P < 0.001, respectively, vs. ISO) in serum and heart, and SIRT3 and pS9-GSK-3β (P < 001 and P < 0.05, respectively, vs. ISO) in heart tissue. Combination of exercise with WTS prevented the hookah smoke-induced alterations in apoptotic markers, cardiac functional indices, and SIRT1, SIRT3, klotho, and pS9-GSK-3β proteins. The findings demonstrated that hookah smoke inhalation intensifies ventricular dysfunction and decreases heart resistance to harmful stresses. Moderate-intensity exercise training attenuated these complications partly through recovering the klotho and sirtuins levels and apoptosis-survival balancing.

Mechanotransduction regulates inflammation responses of epicardial adipocytes in cardiovascular diseases

Adipose tissue is a crucial regulator in maintaining cardiovascular homeostasis by secreting various bioactive products to mediate the physiological function of the cardiovascular system. Accumulating evidence shows that adipose tissue disorders contribute to several kinds of cardiovascular disease (CVD). Furthermore, the adipose tissue would present various biological effects depending on its tissue localization and metabolic statuses, deciding the individual cardiometabolic risk. Crosstalk between adipose and myocardial tissue is involved in the pathophysiological process of arrhythmogenic right ventricular cardiomyopathy (ARVC), cardiac fibrosis, heart failure, and myocardial infarction/atherosclerosis. The abnormal distribution of adipose tissue in the heart might yield direct and/or indirect effects on cardiac function. Moreover, mechanical transduction is critical for adipocytes in differentiation, proliferation, functional maturity, and homeostasis maintenance. Therefore, understanding the features of mechanotransduction pathways in the cellular ontogeny of adipose tissue is vital for underlining the development of adipocytes involved in cardiovascular disorders, which would preliminarily contribute positive implications on a novel therapeutic invention for cardiovascular diseases. In this review, we aim to clarify the role of mechanical stress in cardiac adipocyte homeostasis and its interplay with maintaining cardiac function.

Role of nucleus accumbens microRNA-181a and MeCP2 in incubation of heroin craving in male rats

RATIONALE

Epigenetic regulation has been implicated in the incubation of drug craving (the time-dependent increase in drug seeking after prolonged withdrawal from drug self-administration). There is little information available on the role of microRNAs in incubation of heroin craving.

OBJECTIVE

This study aimed to investigate the roles and mechanisms of miR-181a and methyl CpG binding protein 2 (MeCP2) in the nucleus accumbens (NAc) in incubation of heroin seeking.

METHODS

MiRNA sequencing was used to predict potential miRNAs, and miRNA profiles were performed in the NAc after 1 day or 14 days after withdrawal from heroin self-administration. Following 14 days of heroin self-administration, rats were injected of lentiviral vectors into the NAc and evaluated for the effects of overexpression of miR-181a or knockdown of MeCP2 on non-reinforced heroin seeking after 14 withdrawal days.

RESULTS

Lever presses during the heroin-seeking tests were higher after 14 withdrawal days than after 1 day (incubation of heroin craving). miR-181a expression in NAc was lower after 14 withdrawal days than after 1 day, and meCP2 expression in NAc was higher after 14 days than after 1 day. Luciferase activity assay showed that the 3'UTR of MeCP2 is directly regulated by miR-181a. Overexpression of miR-181a in NAc decreased heroin seeking after 14 withdrawal days and decreased MeCP2 mRNA and protein expression. Knockdown of MeCP2 expression in NAc by LV-siRNA-MeCP2 also decreased heroin seeking after 14 withdrawal days.

CONCLUSIONS

Results indicate that incubation of heroin craving is mediated in part by time-dependent decreases in NAc miR181a expression that leads to time-dependent increases in MeCP2 expression. Our data suggest that NAc miR-181a and MeCP2 contribute to incubation of heroin craving.

Epimutational effects of electronic cigarettes

Electronic cigarettes (e-cigarettes), since they do not require tobacco combustion, have traditionally been considered less harmful than conventional cigarettes (c-cigarettes). In recent years, however, researchers have found many toxic compounds in the aerosols of e-cigarettes, and numerous studies have shown that e-cigarettes can adversely affect the human epigenome. In this review, we provide an update on recent findings regarding epigenetic outcomes of e-cigarette aerosols. Moreover, we discussed the effects of several typical e-cigarette ingredients (nicotine, tobacco-specific nitrosamines, volatile organic compounds, carbonyl compounds, and toxic metals) on DNA methylation, histone modifications, and noncoding RNA expression. These epigenetic effects could explain some of the diseases caused by e-cigarettes. It also reminds the public that like c-cigarettes, inhaling e-cigarette aerosols could also be accompanied with potential epigenotoxicity on the human body.

EnDuo, a novel derivative of Endostar, inhibits the migration of colon cancer cells, suppresses matrix metalloproteinase-2/9 expression and impedes AKT/ERK activation

BACKGROUND/AIMS

Colon cancer remains a life-threating disease with increasing morbidity and mortality worldwide despite the advancement in modern medical treatment. Therefore, novel and effective anti-colon cancers drugs are urgently needed. In this study, we investigated the anti-metastatic property EnDuo, a modified version of Endostar, and the underlying mechanisms.

METHODS

Colon cancer cells were treated with different concentrations of EnDuo (50 μg/mL, 100 μg/mL, 200 μg/mL), and Endostar (100 μg/mL) as positive control. Cell Counting Kit-8 assay was performed to test the effect of EnDuo on cell viability. A scratch wound assay and transwell assay were employed to evaluate the relocation and motility of malignant colon cells following treatment with EnDuo. Western blot analysis was used to determine inhibitory effects of EnDuo by detecting the phosphorylation level of AKT and ERK proteins, and the expression of MMP-2 and MMP-9 proteins.

RESULTS

Our results showed that EnDuo impedes the migration of colon cancer cells in a dose-dependent manner. At the molecular level, EnDuo induced a significant reduction in the phosphorylation of AKT and ERK proteins, and inhibited the expression of MMP-2 and MMP-9 proteins.

CONCLUSIONS

Collectively, these results demonstrate that EnDuo exhibits a comparable anti-metastatic effect by suppressing the migration of colon cancer cells. Possibly, EnDuo interrupts the PI3K/AKT/ERK signaling pathway to arrest cell migration. Our study provides a novel insight to the potential clinical applications of EnDuo against colon cancers in the future.

MicroRNAs as regulators of ERK/MAPK pathway: A comprehensive review

The ERK/MAPK cascade is one the four distinctive MAPK cascades which transmit extracellular signals to intracellular targets. This cascade has an important role in the regulation of several fundamental processes such as proliferation, differentiation and cell response to diverse extrinsic stresses. Moreover, several studies have shown participation of this cascade in the pathogenesis of cancer. Recent investigations have unraveled interaction between microRNAs (miRNAs) and ERK/MAPK cascade. These transcripts reside in both upstream and downstream of this cascade, regulating or being regulated by ERK/MAPK proteins. In the current review, we summarize the role of miRNAs in the regulation of ERK/MAPK and their contribution in the pathogenesis of human disorders with particular focus on cancers.

PERK-Mediated Suppression of microRNAs by Sildenafil Improves Mitochondrial Dysfunction in Heart Failure

Oxidative/nitrosative stress is a major trigger of cardiac dysfunction, involving the unfolded protein response and mitochondrial dysfunction. Activation of nitric oxide-cyclic guanosine monophosphate-protein kinase G signaling by sildenafil improves cardiac mal-remodeling during pressure-overload-induced heart failure. Transcriptome analysis was conducted in failing hearts with or without sildenafil treatment. Protein kinase R-like endoplasmic reticulum (ER) kinase (PERK) downstream signaling pathways, EIF2 and NRF2, were significantly altered. Although EIF2 signaling was suppressed, NRF2 signaling was upregulated, inhibiting the maturation of miR 24-3p through EGFR-mediated Ago2 phosphorylation. To study the effect of sildenafil on these pathways, we generated cardiac-specific PERK knockout mice. In these mice, sildenafil could not inhibit the maturations, the nuclear translocation of NRF2 was suppressed, and mitochondrial dysfunction advanced. Altogether, these results show that PERK-mediated suppression of miRNAs by sildenafil is vital for maintaining mitochondrial homeostasis through NRF2-mediated oxidative stress response.

Nicotine induces cardiac toxicity through blocking mitophagic clearance in young adult rat

Since an outbreak of vaping-related deaths in the US has been reported as a public health crisis, the cardiovascular safety of nicotine nowadays receives increasing attention due to use of tobacco cigarette alternatives, such as electronic cigarettes. However, whether and how nicotine contributes to cardiac detrimental effects are in great controversy, especially less understood in young adult population. We report that chronic nicotine exposure, a major component of Electronic cigarettes, resulted in directly inhibited cardiomyocytes viability, increased cardiac fibrosis, and markedly suppressed cardiac function compared with sham. Gene array combined with bioinformatics analysis identified cardiac apoptosis and mitophagy were the key signals responsible for nicotine induced cardiac detrimental effect. Mechanistically, nicotine exposure markedly increased cleaved Caspase 3 and cleaved Caspase 9 indicating the involvement of intrinsic apoptotic pathway (mitochondrial cell death pathway). Meanwhile, nicotine-induced ROS outbreak promoted lysomal alkalization, furthermore blocked mitophagic degradation, thereby disrupted mitophagic flux promoted mitochondrial cell death cascade. Taken together, these findings indicate that nicotine confers cardiotoxicity via ROS-induced mitophagic flux blockage and provide the first demonstration of a causative link between nicotine and cardiac toxicity in young adult rat which may suggest nicotine induces cardiomyocytes impairment leading to cardiotoxicity in young adult population.

RGD-PEG-PLA Delivers MiR-133 to Infarct Lesions of Acute Myocardial Infarction Model Rats for Cardiac Protection

Studies have shown that microRNA-133 (miR-133) plays a positive role in the growth of cardiac myocytes, the maintenance of cardiac homeostasis, and the recovery of cardiac function, which is of great significance for the recovery of acute myocardial infarction. However, the delivery of miRNA to the site of action remains a challenge at present. The purpose of this study was to design an ideal carrier to facilitate the delivery of miR-133 to the infarct lesion for cardiac protection. A disease model was constructed by ligating the left anterior descending coronary artery of rats, and polyethylene glycol (PEG)-polylactic acid (PLA) nanoparticles modified with arginine-glycine-aspartic acid tripeptide (RGD) carrying miR-133 were injected via the tail vein. The effects of miR-133 were evaluated from multiple perspectives, including cardiac function, blood indexes, histopathology, and myocardial cell apoptosis. The results showed that RGD-PEG-PLA maintained a high level of distribution in the hearts of model rats, indicating the role of the carrier in targeting the heart infarction lesions. RGD-PEG-PLA/miR-133 alleviated cardiac histopathological changes, reduced the apoptosis of cardiomyocytes, and reduced the levels of factors associated with myocardial injury. Studies on the mechanism of miR-133 by immunohistochemistry and polymerase chain reaction demonstrated that the expression level of Sirtuin3 (SIRT3) was increased and that the expression of adenosine monophosphate activated protein kinase (AMPK) decreased in myocardial tissue. In summary, the delivery of miR-133 by RGD-PEG-PLA carrier can achieve cardiac lesion accumulation, thereby improving the cardiac function damage and reducing the myocardial infarction area. The inhibition of cardiomyocyte apoptosis, inflammation, and oxidative stress plays a protective role in the heart. The mechanism may be related to the regulation of the SIRT3/AMPK pathway.

Cytotoxic and genotoxic evaluation of cotinine using human neuroblastoma cells (SH-SY5Y)

Cotinine is the main metabolite of nicotine, which is metabolized in the liver through a cytochrome P450 enzyme. Different studies point to genetic instability caused by nicotine, such as single and double DNA strand breaks and micronuclei formation, but little is known about the effect of cotinine. Therefore, the present in vitro study assessed the effects of cotinine on cell viability and DNA damage in SH-SY5Y neuroblastoma cells, as well as genotoxicity related to oxidative stress mechanisms. Comparisons with nicotine were also performed. An alkaline comet assay modified by repair endonucleases (FPG, OGG1, and Endo III) was used to detect oxidized nucleobases. SH-SY5Y neuronal cells were cultured under standard conditions and exposed for 3 h to different concentrations of cotinine and nicotine. Cytotoxicity was observed at higher doses of cotinine and nicotine in the MTT assay. In the trypan blue assay, cells showed viability above 80% for both compounds. Alkaline comet assay results demonstrated a significant increase in damage index and frequency for cells treated with cotinine and nicotine, presenting genotoxicity. The results of the enzyme-modified comet assay suggest a DNA oxidative damage induced by nicotine. Unlike other studies, our results demonstrated genotoxicity induced by both cotinine and nicotine. The similar effects observed for these two pyridine alkaloids may be due to the similarity of their structures.

Aloe-emodin attenuates myocardial infarction and apoptosis via up-regulating miR-133 expression

Aloe-emodin (AE) is an anthraquinone derived from rhubarb and has a variety of pharmacological actions. However, the role of AE in regulating ischemic heart diseases is still unclear. The present study investigated the effect of AE on cardiac injuries induced by myocardial infarction (MI) in vivo and oxidative insults in vitro and explored the mechanisms involved. TUNEL and Flow cytometry were performed to measure cell apoptosis. Western blot analysis was employed to detect expression of Bcl-2, Bax and Caspase-3 proteins. Real-time PCR was used to quantify the microRNAs levels. Our data showed that AE protected neonatal rat ventricular myocytes (NRVMs) from hydrogen peroxide (H₂O₂) induced apoptosis and significantly inhibited H₂O₂-induced reactive oxygen species (ROS) elevation. Furthermore, AE treatment significantly reversed H₂O₂-induced upregulation of Bax/Bcl-2 and the loss of mitochondrial membrane potential. In vivo, AE treatment significantly reduced infarct size, ameliorated impaired cardiac function and obviously decreased cardiac apoptosis and oxidative stress in MI mice heart. Meanwhile, AE restored H₂O₂-induced downregulation of miR-133, and transfection with miR-133 inhibitor abolished the anti-apoptotic and anti-oxidative effects of AE. Moreover, AE prevented H₂O₂-induced increase in caspase-3 activity, which was diminished by application of miR-133 inhibitor. Our results indicate that AE protectes against myocardial infarction via the upregulation of miR-133, inhibition of ROS production and suppression of caspase-3 apoptotic signaling pathway.

MicroRNA expression profiling of nicotine-treated human periodontal ligament cells

Cigarette smoking is a lifestyle-related risk factor involved in the causation and progression of periodontal disease. Nicotine is a key toxic component of tobacco. However, the mechanisms underlying nicotine-induced periodontitis have not yet been fully elucidated. The present study investigated the microRNA (miRNA) expression profile of human periodontal ligament cells (PDLCs) treated with nicotine. Using differential analysis of miRNA array data, several differentially expressed miRNAs were identified in nicotine-treated PDLCs. Quantitative real-time PCR was employed to verify the accuracy of the miRNA array, and the targets of these dysregulated miRNAs were further analyzed. Function and pathway enrichment of differentially expressed miRNAs suggested that several important signaling pathways, such as the Toll-like receptor signaling pathway, nicotine addiction, the transforming growth factor-beta signaling pathway, and the hypoxia inducible factor-1 signaling pathway, are potentially responsible for nicotine-induced periodontitis. This study has helped to clarify the epigenetic mechanisms of nicotine-induced periodontitis, highlighting novel biomarkers and therapeutic targets.

miR-133b Downregulation Reduces Vulnerable Plaque Formation in Mice with AS through Inhibiting Macrophage Immune Responses

Atherosclerosis (AS) is a chronic inflammatory disease characterized by accumulating deposition of lipids in the arterial intima. Notably, macrophages participate centrally in the pathogenesis of this deadly disease. In this study, we established AS mouse models in order to investigate the effect of microRNA-133b (miR-133b) on vulnerable plaque formation and vascular remodeling in AS and explore the potential functional mechanisms. The expression of miR-133b was altered or the Notch-signaling pathway was blocked in the AS mouse models in order to evaluate the proliferation, migration, and apoptosis of macrophages. It was observed that miR-133b was upregulated in AS, which might target MAML1 to regulate the Notch-signaling pathway. AS mice with downregulated miR-133b or inhibited Notch-signaling pathway presented with a reduced AS plaque area, a decreased positive rate of macrophages, and an increased positive rate of vascular smooth muscle cells. Moreover, Notch-signaling pathway blockade or miR-133b downregulation inhibited the macrophage viability and migration and accelerated the apoptosis. This study provides evidence that downregulated miR-133b expression may inhibit the immune responses of macrophages and attenuate the vulnerable plaque formation and vascular remodeling in AS mice through the MAML1-mediated Notch-signaling pathway, highlighting miR-133b as a novel therapeutic target for AS.

Alteration in cardiac PI3K/Akt/mTOR and ERK signaling pathways with the use of growth hormone and swimming, and the roles of miR21 and miR133

Athletes misuse recombinant human growth hormone (r-hGH) to enhance their performance. Although r-hGH is known to increase cardiac hypertrophy, the underlying molecular mechanism remains unclear. The aim of the present study was to investigate the role of r-hGH in cardiac intracellular signaling pathways and of miR-21 and miR-133 expression in rat hearts during exercise. A total of 36 adult male Sprague-Dawley rats were divided into sedentary control (SC, n=9), swimming exercise (SE, n=8), r-hGH (GH, n=10) and swimming exercise plus r-hGH (SE-GH, n=9) groups. The exercise groups completed a 1-h swimming exercise 5 times a week for 8 weeks. Subcutaneous r-hGH was administered as 0.3 mg/kg/day. Phosphoinositide-3-kinase (PI3K), serine/threonine protein kinase 1 (AKT1), extracellular signal-regulated kinase (ERK), microRNA (miR)-21 and miR-133 expression was evaluated in ventricular muscle by real-time quantitative polymerase chain reaction. Protein expression of PI3K, AKT1, ERK and mechanistic target of rapamycin (mTOR) was also assessed by immunohistochemistry. Statistical differences were analyzed by two-way ANOVA. PI3K and AKT1 expression and the gene and protein levels was notably increased in the SE-GH group compared with in SC ventricular tissues (P<0.05). mTOR protein expression was higher in the GH, SE and SE-GH groups compared with in the SC group (P<0.05, <0.05 and <0.001, respectively). ERK gene/protein expression was similar across all groups. miR-21 and miR-133 levels in ventricular muscle were higher in the SE and GH groups than those in the SC group. In summary, growth hormone application coupled with swimming exercise appeared to affect the PI3K/AKT/mTOR signaling pathway in the left ventricular tissue of rats; however, ERK signaling pathway appeared inactive in physiological left ventricular hypertrophy caused by swimming and GH administration over 8 weeks. Furthermore, GH treatment resulted in increased miR-21 and miR-133 expression. Future study by our group will aim to assess the effects of higher dose GH treatment.

MicroRNA-150 contributes to ischemic stroke through its effect on cerebral cortical neuron survival and function by inhibiting ERK1/2 axis via Mal

Ischemic stroke, caused by the blockage of blood supply, is a major cause of death worldwide. For identifying potential candidates, we explored the effects microRNA-150 (miR-150) has on ischemic stroke and its underlying mechanism by developing a stable middle cerebral artery occlusion (MCAO) rat model. Gene expression microarray analysis was performed to screen differentially expressed genes associated with MCAO. We evaluated the expression of miR-150 and Mal and the status of ERK1/2 axis in the brain tissues of MCAO rats. Then the cerebral cortical neurons (CCNs) were obtained and introduced with elevated or suppressed miR-150 or silenced Mal to validate regulatory mechanisms for miR-150 governing Mal in vitro. The relationship between miR-150 and Mal was verified by dual luciferase reporter gene assay. Besides, cell growth and apoptosis of CCNs were detected by means of MTT assay and flow cytometry analyses. We identified Mal as a downregulated gene in MCAO, based on the microarray data of GSE16561. MiR-150 was over-expressed and negatively targeted Mal in the brain tissues obtained from MCAO rats and their CCNs. Increasing miR-150 blocked the ERK1/2 axis, resulting in an inhibited cell growth of CNNs but an enhanced apoptosis. Furthermore, MiR-150 inhibition was observed to have effects on CNNs as opposed to those inhibited by miR-150 promotion. The key findings of this study support the notion that miR-150 under-expression-mediated direct promotion of Mal protects CNN functions through the activation of the ERK1/2 axis, and underscore the concept that miR-150 may represent a novel pharmacological target for ischemic stroke intervention.

Gestational Hypoxia and Developmental Plasticity

Hypoxia is one of the most common and severe challenges to the maintenance of homeostasis. Oxygen sensing is a property of all tissues, and the response to hypoxia is multidimensional involving complicated intracellular networks concerned with the transduction of hypoxia-induced responses. Of all the stresses to which the fetus and newborn infant are subjected, perhaps the most important and clinically relevant is that of hypoxia. Hypoxia during gestation impacts both the mother and fetal development through interactions with an individual's genetic traits acquired over multiple generations by natural selection and changes in gene expression patterns by altering the epigenetic code. Changes in the epigenome determine "genomic plasticity," i.e., the ability of genes to be differentially expressed according to environmental cues. The genomic plasticity defined by epigenomic mechanisms including DNA methylation, histone modifications, and noncoding RNAs during development is the mechanistic substrate for phenotypic programming that determines physiological response and risk for healthy or deleterious outcomes. This review explores the impact of gestational hypoxia on maternal health and fetal development, and epigenetic mechanisms of developmental plasticity with emphasis on the uteroplacental circulation, heart development, cerebral circulation, pulmonary development, and the hypothalamic-pituitary-adrenal axis and adipose tissue. The complex molecular and epigenetic interactions that may impact an individual's physiology and developmental programming of health and disease later in life are discussed.

Nicotine upregulates FGFR3 and RB1 expression and promotes non-small cell lung cancer cell proliferation and epithelial-to-mesenchymal transition via downregulation of miR-99b and miR-192

BACKGROUND

Tobacco smoke is by far the greatest risk factor for non-small-cell lung cancer (NSCLC). Nicotine, an active alkaloid in tobacco, is unable to initiate tumorigenesis in humans and rodents, but can promote the growth and metastasis of various tumors, including NSCLC, initiated by tobacco carcinogens. Recently, cigarette smoke is reported to downregulate 24 miRNAs more than 3-fold in the lungs of rats, and most of these downregulated miRNAs are associated with NSCLC initiation and development. Nicotine as the major tobacco component might be associated with the expression changes of some miRNAs.

METHODS

qRT-PCR was performed to determine the miRNA and mRNA expression, and western blot was conducted to measure protein expression. MTT assay was used to detect cell proliferation.

RESULTS

The effects of nicotine on the expression of 24 miRNAs in NSCLC cell lines were determined, and the results showed that nicotine treatment decreased miR-99b and miR-192 expression. Cell proliferation and epithelial-to-mesenchymal transition (EMT) detection showed that nicotine promoted NSCLC cell proliferation and EMT, and restoration of miR-99b or miR-192 expression relieved the effects of nicotine on NSCLC cell proliferation and EMT. Subsequently, fibroblast growth factor receptor 3 (FGFR3) and retinoblastoma 1 (RB1) were confirmed to be the targets of miR-99b and miR-192, respectively, and were upregulated by nicotine in NSCLC cells. In addition, FGFR3 or RB1 knockdown inhibited NSCLC cell proliferation and EMT.

CONCLUSION

This study, for the first time, elucidates nicotine-miR-99b/miR-192-FGFR3/RB1 regulatory network that nicotine promotes NSCLC cell proliferation and EMT by downregulating miR-99b and miR-192, and upregulating their targets FGFR3 and RB1. These findings offer novel insights into the understanding of underlying molecular mechanisms of NSCLC related with the nicotine effects.

miR‑133b‑5p contributes to hypoxic preconditioning‑mediated cardioprotection by inhibiting the activation of caspase‑8 and caspase-3 in cardiomyocytes

In a previous study using a microRNA (miRNA/miR) microarray assay, we demonstrated that miR-133b-5p was upregulated in response to hypoxic preconditioning (HPC). The present study was designed to investigate the role of the miR‑133b‑5p in HPC‑induced cardioprotection and the underlying mechanisms involving caspase‑8 and caspase‑3 apoptotic signaling. Adult rats were subjected to myocardial ischemia/reperfusion (I/R) injury with or without ischemic preconditioning (IPC), and the level of miR‑133b‑5p in myocardium was measured. Neonatal rat cardiomyocytes were isolated and subjected to hypoxia/reoxygenation (H/R) injury, with or without HPC. miR‑133b‑5p antagomir was transfected into the cardiomyocytes to observe whether it could block HPC‑induced cardioprotection. Cellular injury was evaluated by detecting cell viability, lactate dehydrogenase (LDH) activity and apoptotic rate. Reverse transcription‑quantitative polymerase chain reaction was used to measure the level of miR‑133b‑5p. The activation of caspase‑8 and caspase‑3 were measured by western blot analysis to detect the cleaved fragments as well as a colorimetric assay. Following myocardial I/R injury, the expression of miR‑133b‑5p was decreased in myocardium, while this decrease was restored by IPC. HPC protected neonatal rat cardiomyocytes against H/R injury by increasing cell viability, while reducing LDH release and cell apoptosis. These protective effects were coupled with the upregulation of miR‑133b‑5p. However, the knockdown of miR‑133b‑5p in the cardiomyocytes blocked HPC‑mediated cardioprotection as reflected by the aggravation of cell injury and apoptosis. HPC upregulated miR‑133b‑5p level was markedly suppressed by the antagomir. In addition, the cleavage and activities of caspase‑8 and caspase‑3 were inhibited by HPC while reversed by knockdown of miR‑133b‑5p. Upregulation of miR‑133b‑5p contributes to HPC‑mediated cardioprotection in cardiomyocytes, and the mechanism may be associated with inhibition of caspase‑8 and caspase‑3 apoptotic signaling.

Identification and characterization of microRNAs in the intestinal tissues of sheep (Ovis aries)

Sheep are small ruminants, and their long intestines exhibit high digestive and absorptive capacity in many different rearing conditions; however, the genetic bases of this characteristic remains unclear. MicroRNAs (miRNAs) play a major role in maintaining both intestinal morphological structure as well as in regulating the physiological functions of this organ. However, no study has reported on the miRNA expression profile in the intestinal tissues of sheep. Here, we analyzed and identified the miRNA expression profile of three different intestinal tissues (i.e., duodenum, cecum, and colon) of sheep (Ovis aries) using high-throughput sequencing and bioinformatic methods. In total, 106 known miRNAs were identified, 458 conserved miRNAs were detected, 192 unannotated novel miRNAs were predicted, and 195 differentially expressed miRNAs were found between the different tissues. Additionally, 3,437 candidate target genes were predicted, and 17 non-redundant significantly enriched GO terms were identified using enrichment analysis. A total of 99 candidate target genes were found to significantly enriched in 4 KEGG biological pathways. A combined regulatory network was constructed based on 92 metabolism-related candidate target genes and 65 differentially expressed miRNAs, among which 7 miRNAs were identified as hub miRNAs. Via these mechanisms, miRNAs may play a role in maintaining intestinal homeostasis and metabolism. This study helps to further explain the mechanisms that underlie differences in tissue morphology and function in three intestinal segments of sheep.

Metformin synergistically enhances antitumor activity of cisplatin in gallbladder cancer via the PI3K/AKT/ERK pathway

Metformin (Met) is a widely used antidiabetic drug and has demonstrated interesting anticancer effects in various cancer models, alone or in combination with chemotherapeutic drugs. The aim of the present study is to investigate the synergistic effect of Met with cisplatin (Cis) on the tumor growth inhibition of gallbladder cancer cells (GBC-SD and SGC-996) and explore the underlying mechanism. Cells were treated with Met and/or Cis and subjected to cell viability, colony formation, apoptosis, cell cycle, western blotting, xenograft tumorigenicity assay and immunohistochemistry. The results demonstrated that Met and Cis inhibited the proliferation of gallbladder cancer cells, and combination treatment with Met and Cis resulted in a combination index < 1, indicating a synergistic effect. Co-treatment with Met and Cis caused G0/G1 phase arrest by upregulating P21, P27 and downregulating CyclinD1, and induced apoptosis through decreasing the expression of p-PI3K, p-AKT, and p-ERK. In addition, pretreatment with a specific AKT activator (IGF-1) significantly neutralized the pro-apoptotic activity of Met + Cis, suggesting the key role of AKT in this process. More importantly, in nude mice model, Met and Cis in combination displayed more efficient inhibition of tumor weight and volume in the SGC-996 xenograft mouse model than Met or Cis alone. Immunohistochemistry analysis suggests the combinations greatly suppressed tumor proliferation, which is consistent with our in vitro results. In conclusion, our findings indicate that the combination therapy with Met and Cis exerted synergistic antitumor effects in gallbladder cancer cells through PI3K/AKT/ERK pathway, and combination treatment with Met and Cis would be a promising therapeutic strategy for gallbladder cancer patients.

Tanshinone IIA ameliorates apoptosis of myocardiocytes by up-regulation of miR-133 and suppression of Caspase-9

To explore the potential protective effect of Tanshinone ⅡA on myocardial cell apoptosis and elucidate the underlying molecular mechanisms. The rat heart cell H9c2 was treated by either H₂O₂ or doxorubicin (DOX) to mimic oxidative stress and DNA damage conditions in vivo. Cell growth was monitored by optical microscope observation or CCK-8 counting kit. The relative expression of miR-133 and U6 snoRNA was semi-quantitated by RT-PCR or real-time PCR. Cell apoptosis was analyzed by flow cytometry with Annexin V/PI double staining. The microRNA binding sites were predicted by online bioinformatics tools. The regulatory effect of miR-133 on caspase-9 was measured by luciferase reporter assay. Apoptosis pathway factors were analyzed by immunoblotting. Our data demonstrated that Tanshinone ⅡA significantly ameliorated myocardial apoptosis induced by either H₂O₂ or DOX. The protective effect was likely mediated by up-regulation of miR-133. We further identified Caspase-9 as the target of miR-133. Tanshinone ⅡA treatment significantly reversed down-regulation of miR-133 under harsh conditions and in turn suppressed evoking of Caspase-9 and related apoptotic effectors, which consequently contributed to the improvement of myocardial injury. In conclusion, Tanshinone ⅡA ameliorated myocardial apoptosis via restoration of miR-133 and suppression Caspase-9 signaling cascade, which underlies its well-proven clinical benefit and warrants larger scale clinical applications.

Vitamin K2 promotes mesenchymal stem cell differentiation by inhibiting miR‑133a expression

Vitamin K₂ has been demonstrated to promote the osteogenic differentiation of mesenchymal stem cells; however, the mechanisms underlying this effect remain unclear. As microRNA (miR)-133a has been identified as a negative regulator of osteogenic differentiation, the present study hypothesized that vitamin K₂ promoted osteogenesis by inhibiting miR-133a. Using human bone marrow stromal cells (hBMSCs) overexpressing miR-133a, or a control, the expression levels of osteogenesis-associated proteins, including runt-related transcription factor 2, alkaline phosphatase and osteocalcin, were analyzed. miR-133a significantly suppressed the osteogenic differentiation of hBMSCs. To determine the effect of vitamin K₂ on miR-133a expression and osteogenesis, hBMSCs were treated with vitamin K₂. Vitamin K₂ inhibited miR-133a expression, which was accompanied by enhanced osteogenic differentiation. Furthermore, the expression levels of vitamin K epoxide reductase complex subunit 1, the key protein in γ-carboxylation, were downregulated by miR-133a overexpression and upregulated by vitamin K₂ treatment, indicating a positive feedback on γ-carboxylation. The results of the present study suggested that vitamin K₂ targets miR-133a to regulate osteogenesis.

MicroRNAs as regulators of drug abuse and immunity

MicroRNAs (miRNAs) are 20-22 nucleotide non-coding RNAs that participate in gene regulation. They bind to 3'-untranslated regions of their mRNA targets, inhibiting the transcripts' translation and/or destabilizing them. Chronic drug abuse induces changes of miRNAs expression in the brain, which is thought to contribute to addictive behaviors. Lots of miRNAs have been identified to play critical roles in the development of drug addiction. Moreover, miRNAs have been shown to play critical roles in a broad array of biologic processes, including regulation of the cell cycle, oncogenic transformation, immune cell regeneration and differentiation, and psychiatry disorders. We hypothesized that chronic drug abuse leads to aberrant expression of several miRNAs, and then aberrant miRNAs influence the innate and adaptive immunity, especially differentiation and function of T cells and B cells, through down-regulated miRNAs' target gene expression. Characterization of miRNA actions is important and has high potential effect for the management of drug addiction and immunity diseases. miRNAs are potential biomarkers, and the modulation of their expression can be used for therapeutic purposes.

Noncoding RNA Profiles in Tobacco- and Alcohol-Associated Diseases

Tobacco and alcohol are the leading environmental risk factors in the development of human diseases, such as cancer, cardiovascular disease, and liver injury. Despite the copious amount of research on this topic, by 2030, 8.3 million deaths are projected to occur worldwide due to tobacco use. The expression of noncoding RNAs, primarily microRNAs (miRNAs) and long noncoding RNAs (lncRNAs), is modulated by tobacco and alcohol consumption. Drinking alcohol and smoking cigarettes can modulate the expression of miRNAs and lncRNAs through various signaling pathways, such as apoptosis, angiogenesis, and inflammatory pathways—primarily interleukin 6 (IL-6)/signal transducer and activator of transcription 3 (STAT3), which seems to play a major role in the development of diseases associated with these risk factors. Since they may be predictive and prognostic biomarkers, they can be used both as predictors of the response to therapy and as a targeted therapy. Further, circulating miRNAs might be valuable noninvasive tools that can be used to examine diseases that are related to the use of tobacco and alcohol. This review discusses the function of noncoding RNAs in cancer and other human tobacco- and alcohol-associated diseases.

Characterization and Functional Analysis of Extracellular Vesicles and Muscle-Abundant miRNAs (miR-1, miR-133a, and miR-206) in C2C12 Myocytes and mdx Mice

Duchenne muscular dystrophy (DMD) is a progressive neuromuscular disorder. Here, we show that the CD63 antigen, which is located on the surface of extracellular vesicles (EVs), is associated with increased levels of muscle-abundant miRNAs, namely myomiRs miR-1, miR-133a, and miR-206, in the sera of DMD patients and mdx mice. Furthermore, the release of EVs from the murine myoblast C₂C₁₂ cell line was found to be modulated by intracellular ceramide levels in a Ca²⁺-dependent manner. Next, to investigate the effects of EVs on cell survival, C₂C₁₂ myoblasts and myotubes were cultured with EVs from the sera of mdx mice or C₂C₁₂ cells overexpressing myomiRs in presence of cellular stresses. Both the exposure of C₂C₁₂ myoblasts and myotubes to EVs from the serum of mdx mice, and the overexpression of miR-133a in C₂C₁₂ cells in presence of cellular stress resulted in a significant decrease in cell death. Finally, to assess whether miRNAs regulate skeletal muscle regeneration in vivo, we intraperitoneally injected GW4869 (an inhibitor of exosome secretion) into mdx mice for 5 and 10 days. Levels of miRNAs and creatine kinase in the serum of GW4869-treated mdx mice were significantly downregulated compared with those of controls. The tibialis anterior muscles of the GW4869-treated mdx mice showed a robust decrease in Evans blue dye uptake. Collectively, these results indicate that EVs and myomiRs might protect the skeletal muscle of mdx mice from degeneration.

Nicotine plus a high-fat diet triggers cardiomyocyte apoptosis

Cigarette smoking is an important risk factor for diabetes, cardiovascular disease and non-alcoholic fatty liver disease. The health risk associated with smoking can be aggravated by obesity. Smoking might also trigger cardiomyocyte (CM) apoptosis. Given that CM apoptosis has been implicated as a potential mechanism in the development of cardiomyopathy and heart failure, we characterize the key signaling pathways in nicotine plus high-fat diet (HFD)-induced CM apoptosis. Adult C57BL6 male mice were fed a normal diet (ND) or HFD and received twice-daily intraperitoneal (IP) injections of nicotine (0.75 mg/kg body weight [BW]) or saline for 16 weeks. An additional group of nicotine-treated mice on HFD received twice-daily IP injections of mecamylamine (1 mg/kg BW), a non-selective nicotinic acetylcholine receptor antagonist, for 16 weeks. Nicotine when combined with HFD led to a massive increase in CM apoptosis that was fully prevented by mecamylamine treatment. Induction of CM apoptosis was associated with increased oxidative stress and activation of caspase-2-mediated intrinsic pathway signaling coupled with inactivation of AMP-activated protein kinase (AMPK). Furthermore, nicotine treatment significantly (P < 0.05) attenuated the HFD-induced decrease in fibroblast growth factor 21 (FGF21) and silent information regulator 1 (SIRT1). We conclude that nicotine, when combined with HFD, triggers CM apoptosis through the generation of oxidative stress and inactivation of AMPK together with the activation of caspase-2-mediated intrinsic apoptotic signaling independently of FGF21 and SIRT1.

miR-181a is a negative regulator of GRIA2 in methamphetamine-use disorder

A previous study reported that the miR-181a level in serum was significantly different between patients with methamphetamine-use disorder and healthy controls and that chronic methamphetamine use down-regulates the expression of miR-181a. Bioinformatic analysis predicted that miR-181a might bind the 3′-UTRs of the mRNA transcripts of the human glutamate receptor genes GRIA2 and GABRA1. In this study, we measured the expression of GRIA2 and GABRA1 in patients with methamphetamine-use disorder. In addition, we examined whether miR-181a down-regulates GRIA2 and GABRA1 in a cell-based assay. We further examined the effects of chronic methamphetamine exposure on the expression of miR-181a, GRIA2 and GABRA1. The results demonstrated that serum GRIA2 is higher in patients with methamphetamine-use disorder than in healthy controls. Dual luciferase reporter assays and a cell-based model of methamphetamine exposure also showed that miR-181a directly regulates expression of GRIA2. This study supports the evidence that miR-181a and the glutamate AMPA receptor gene GRIA2 play a critical role in methamphetamine-use disorder.

Tanshinone IIA ameliorates apoptosis of cardiomyocytes induced by endoplasmic reticulum stress

The fat-soluble diterpenoids tanshinone IIA (TSA) is the major active element of Danshen, which has widespread cardioprotective effect. However, the mechanism of its beneficial effect on cardiomyocytes has not been fully investigated. Here, we aim to demonstrate that TSA ameliorates apoptosis of cardiomyocytes activated by endoplasmic reticulum stress (ERS). Primary cultures of neonatal rat cardiomyocytes are used, in which ERS-mediated apoptosis is induced by tunicamycin (Tm). Apoptosis of cardiomyocytes are detected by Hoechst staining and caspase 3 activity analysis. Protein expression of ERS markers are detected by Western blot, and level of miroRNA-133 (miR-133) is detected by real-time polymerase chain reaction. Tm treatment significantly triggers the apoptosis and ERS of cardiomyocytes. TSA dramatically ameliorates apoptosis and ERS of cardiomyocytes induced by Tm. Interestingly, level of miR-133 is reduced by Tm treatment, which is reversed by TSA. The cardioprotective effect of TSA on apoptosis and ERS of cardiomyocytes is blocked by anti-miR-133. These results suggest that TSA protects cardiomyocytes through ameliorated ERS-mediated apoptosis, which may be resulted from upregulation of miR-133.

Antiapoptotic Effect of Recombinant HMGB1 A-box Protein via Regulation of microRNA-21 in Myocardial Ischemia-Reperfusion Injury Model in Rats

The ~80 amino acid A box DNA-binding domain of high mobility group box 1 (HMGB1) protein antagonizes proinflammatory responses during myocardial ischemia reperfusion (I/R) injury. The exact role of microRNA-21 (miR-21) is unknown, but its altered levels are evident in I/R injury. This study examined the roles of HMGB1 A-box and miR-21 in rat myocardial I/R injury model. Sixty Sprague-Dawley rats were randomly divided into six equal groups: (1) Sham; (2) I/R; (3) Ischemic postconditioning (IPost); (4) AntagomiR-21 post-treatment; (5) Recombinant HMGB1 A-box pretreatment; and (6) Recombinant HMGB1 A-box + antagomiR-21 post-treatment. Hemodynamic indexes, arrhythmia scores, ischemic area and infarct size, myocardial injury, and related parameters were studied. Expression of miR-21 was detected by real-time quantitative polymerase chain reaction (qRT-PCR) and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay was used to quantify apoptosis. Left ventricular systolic pressure (LVSP), left ventricular end diastolic pressure (LVEDP), maximal rate of pressure rise (+dp/dtmax), and decline (-dp/dtmax) showed clear reduction upon treatment with recombinant HMGB1 A-box. Arrhythmia was relieved and infarct area decreased in the group pretreated with recombinant HMGB1 A-box, compared with other groups. Circulating lactate dehydrogenase (LDH) and malondialdehyde (MDA) levels increased in response to irreversible cellular injury, while creatine kinase MB isoenzymes (CK-MB) and superoxide dismutase (SOD) activities were reduced in the I/R group, which was reversed following recombinant HMGB1 A-box treatment. Interestingly, pretreatment with recombinant HMGB1 A-box showed the most dramatic reductions in miR-21 levels, compared with other groups. Significantly reduced apoptotic index (AI) was seen in recombinant HMGB1 A-box pretreatment group and recombinant HMGB1 A-box + antagomiR-21 post-treatment group, with the former showing a more dramatic lowering in AI than the latter. Bax, caspase-8, and CHOP showed reduced expression, and Bcl-2 and p-AKT levels were upregulated in recombinant HMGB1 A-box pretreatment group. Thus, recombinant HMGB1 A-box treatment protects against I/R injury and the mechanisms may involve inhibition of miR-21 expression.

Regulatory roles of microRNA-21 in fibrosis through interaction with diverse pathways (Review)

MicroRNA-21 (miR-21) is a small, non-coding RNA which can regulate gene expression at the post‑transcriptional level. While the fibrogenic process is vital in tissue repair, proliferation and transition of fibrogenic cells combined with an imbalance of secretion and degradation of the extracellular matrix results in excessive tissue remodeling and fibrosis. Recent studies have indicated that miR‑21 is overexpressed during fibrosis and can regulate the fibrogenic process in a variety of organs and tissues via diverse pathways. The present review summarized the significant roles of miR-21 in fibrosis and discussed the underlying key pathways.

Electrical and mechanical stimulation of cardiac cells and tissue constructs

The field of cardiac tissue engineering has made significant strides over the last few decades, highlighted by the development of human cell derived constructs that have shown increasing functional maturity over time, particularly using bioreactor systems to stimulate the constructs. However, the functionality of these tissues is still unable to match that of native cardiac tissue and many of the stem-cell derived cardiomyocytes display an immature, fetal like phenotype. In this review, we seek to elucidate the biological underpinnings of both mechanical and electrical signaling, as identified via studies related to cardiac development and those related to an evaluation of cardiac disease progression. Next, we review the different types of bioreactors developed to individually deliver electrical and mechanical stimulation to cardiomyocytes in vitro in both two and three-dimensional tissue platforms. Reactors and culture conditions that promote functional cardiomyogenesis in vitro are also highlighted. We then cover the more recent work in the development of bioreactors that combine electrical and mechanical stimulation in order to mimic the complex signaling environment present in vivo. We conclude by offering our impressions on the important next steps for physiologically relevant mechanical and electrical stimulation of cardiac cells and engineered tissue in vitro.

Nicotine Induces Cardiomyocyte Hypertrophy Through TRPC3-Mediated Ca2+/NFAT Signalling Pathway

BACKGROUND

Nicotine is thought to be an important risk factor for the development of cardiovascular diseases. However, the effects of nicotine on cardiomyocyte hypertrophy are poorly understood. The present study was designed to explore the role of nicotine in cardiomyocyte hypertrophy and its underlying mechanism.

METHODS

We used primary cardiomyocytes isolated from Wistar rats to examine the effects of nicotine on intracellular Ca²⁺ mobilization and hypertrophy determined by immunofluorescence, quantitative polymerase chain reaction, and western blot analysis. A luciferase reporter assay was used to examine the activity of NFAT signalling.

RESULTS

We found that nicotine caused cardiomyocyte hypertrophy, which was accompanied by increased intracellular Ca²⁺. Nicotine-enhanced intracellular Ca²⁺ concentration ([Ca²⁺]_i) was significantly abolished by store-operated Ca²⁺ entry (SOCE) and TRPC inhibitors. Knockdown of TRPC3 significantly decreased nicotine-induced SOCE and hypertrophy. Moreover, calcineurin-nuclear factor of activated T cells (NFAT) is involved in TRPC3-mediated Ca²⁺ signalling and cardiomyocyte hypertrophy. Notably, upregulation of TRPC3 by nicotine requires TRPC3-mediated Ca²⁺ influx and calcineurin-NFAT signalling activation.

CONCLUSIONS

Our findings demonstrate that the prohypertrophic effect of nicotine on cardiomyocytes is dependent on enhanced TRPC3 expression through a calcium-dependent regulatory loop, which could become a potential target for prevention and treatment of cardiac hypertrophy.

Oxymatrine synergistically enhances the inhibitory effect of 5-fluorouracil on hepatocellular carcinoma in vitro and in vivo

Oxymatrine (OMT), one of the main active components of extracts from the dry roots of Sophora flavescens, has long been employed clinically to treat cancers. Here, we investigated the synergistic effect of OMT with 5-fluorouracil (5-Fu) on the tumor growth inhibition of hepatocellular carcinoma cells (HCC; Hep-G2 and SMMC-7721) and explored the underlying mechanism. Cells were treated with OMT and/or 5-Fu and subjected to cell viability, colony formation, apoptosis, cell cycle, western blotting, xenograft tumorigenicity assay, and immunohistochemistry. OMT and 5-Fu inhibited the proliferation of Hep-G2 and SMMC-7721 cells, and combination treatment with OMT and 5-Fu resulted in a combination index <1, indicating a synergistic effect. Co-treatment with OMT and 5-Fu caused G0/G1 phase arrest by upregulating P21 and P27 and downregulating cyclin D, and induced apoptosis through increasing the production of reactive oxygen species (ROS) and decreasing the levels of p-ERK. In addition, the inhibition of ROS respectively reversed the cell death induced by 5-Fu + OMT, suggesting the key roles of ROS in the process. More importantly, 5-Fu and OMT in combination exhibit much superior tumor weight and volume inhibition on SMMC-7721 xenograft mouse model in comparison to 5-Fu or OMT alone. Immunohistochemistry analysis suggests the combinations greatly suppressed tumor proliferation, which was consistent with our in vitro results. Taken together, our findings indicated that OMT sensitizes HCC to 5-Fu treatment by the suppression of ERK activation through the overproduction of ROS, and combination treatment with OMT and 5-Fu would be a promising therapeutic strategy for HCC treatment.

MicroRNAs Regulate Mitochondrial Function in Cerebral Ischemia-Reperfusion Injury

Cerebral ischemia-reperfusion injury involves multiple independently fatal terminal pathways in the mitochondria. These pathways include the reactive oxygen species (ROS) generation caused by changes in mitochondrial membrane potential and calcium overload, resulting in apoptosis via cytochrome c (Cyt c) release. In addition, numerous microRNAs are associated with the overall process. In this review, we first briefly summarize the mitochondrial changes in cerebral ischemia-reperfusion and then describe the possible molecular mechanism of miRNA-regulated mitochondrial function, which likely includes oxidative stress and energy metabolism, as well as apoptosis. On the basis of the preceding analysis, we conclude that studies of microRNAs that regulate mitochondrial function will expedite the development of treatments for cerebral ischemia-reperfusion injury.

Comparative Analysis of Differentially Expressed miRNAs and their Downstream mRNAs in Ovarian Cancer and its Associated Endometriosis

Objective

There is an increased risk of developing ovarian cancer (OC) in patients with endometriosis. Hence, development of new biomarkers may provide a positive clinical outcome for early detection. MicroRNAs (miRNAs) are small non-coding RNAs that play an important role in biological and pathological process and are currently used as diagnostic and prognostic markers in various cancers. In the current study, we assessed the differential expression of miRNAs from 19 paired ovarian cancer and its associated endometriosis tissue samples. In addition we also analyzed the downstream targets of those miRNAs.

Methods

Nineteen paired cases of ovarian cancer and endometriosis foci were identified by a gynecologic pathologist and macro-dissected. The total RNAs were extracted and subjected to comprehensive miRNA profiling from the pooled samples of these two different entities using microarray analysis. Later, the abnormal expressions of few selected miRNAs were validated in individual cases by quantitative real-time PCR (qRT-PCR). Ingenuity pathway analysis revealed target mRNAs which were validated by qRT-PCR.

Results

The miRNA profiling identified deregulation of greater than 1156 miRNAs in OC, of which the top seven were further validated by qRT-PCR. The expression of miR-1, miR-133a, and miR-451 were reduced significantly (p<0.0001) in the OC patients compared to its associated endometriosis. In contrast, the expression of miR-141, miR-200a, miR-200c, and miR-3613 were elevated significantly (p<0.05) in most of the OC patients. Furthermore, among the downstream mRNAs of these miRNAs, the level of PTEN expression was significantly (p<0.05) reduced in OC compared to endometriosis while no significant difference was observed in NF-κB expression.

Conclusion

The expression of miRNAs and mRNAs in OC were significantly different compared to its concurrent endometriosis. These differential expressed miRNAs may serve as potential diagnostic and prognostic biomarkers for OC associated with endometriosis.

Lupeol inhibits proliferation and induces apoptosis of human pancreatic cancer PCNA-1 cells through AKT/ERK pathways

Lupeol, a dietary triterpene, present in many fruits and medicinal plants, has been reported to possess many pharmacological properties including anti-cancer activities both in vitro and in vivo. However, the precise mechanism involved remains largely unknown. The present study is conducted to investigate the anti-cancer activity and the underlying mechanisms of lupeol on human pancreatic cancer proliferating cell nuclear antigen 1 (PCNA-1) cells in vitro and in vivo. Lupeol significantly inhibited the proliferation of the cells in dose- and time-dependent manners and induced apoptosis as well as cell cycle arrest in G0/G1 phase by upregulating P21 and P27 and downregulating cyclin D1. The expression of apoptosis-related proteins in cells was evaluated by western blot analysis, and we found that lupeol induced cell apoptosis by decreasing the levels of p-AKT and p-ERK. In addition, pretreatment with a specific PI3K/AKT activator (IGF-1) significantly neutralized the pro-apoptotic activity of lupeol in PCNA-1 cells, demonstrating the important role of AKT in this process. More importantly, our in vivo studies showed that administration of lupeol decreased tumor growth in a dose-dependent manner. Immunohistochemistry analysis demonstrated the downregulation of p-AKT and p-ERK in tumor tissues following lupeol treatment, consistent with the in vitro results. Therefore, these findings indicate that lupeol can inhibit cell proliferation and induce apoptosis as well as cell cycle arrest of PCNA-1 cells and might offer a therapeutic potential advantage for human pancreatic cancer chemoprevention or chemotherapy.