NF-κB-mediated miR-30b regulation in cardiomyocytes cell death by targeting Bcl-2

The interplay of hydrogen sulfide and microRNAs in cardiovascular diseases: insights and future perspectives

Hydrogen sulfide (H2S) is recognized as the third gasotransmitter, after nitric oxide (NO) and carbon monoxide (CO). It is known for its cardioprotective properties, including the relaxation of blood vessels, promotion of angiogenesis, regulation of myocardial cell apoptosis, inhibition of vascular smooth muscle cell proliferation, and reduction of inflammation. Additionally, abnormal H2S generation has been linked to the development of cardiovascular diseases (CVD), such as pulmonary hypertension, hypertension, atherosclerosis, vascular calcification, and myocardial injury. MicroRNAs (miRNAs) are non-coding, conserved, and versatile molecules that primarily influence gene expression by repressing translation and have emerged as biomarkers for CVD diagnosis. Studies have demonstrated that H2S can ameliorate cardiac dysfunction by regulating specific miRNAs, and certain miRNAs can also regulate H2S synthesis. The crosstalk between miRNAs and H2S offers a novel perspective for investigating the pathophysiology, prevention, and treatment of CVD. The present analysis outlines the interactions between H2S and miRNAs and their influence on CVD, providing insights into their future potential and advancement.

Polystyrene microplastics induce myocardial inflammation and cell death via the TLR4/NF-κB pathway in carp

Microplastics (MPs) have attracted widespread attention as an emerging environmental pollutant. Especially in aquatic ecosystems, the harm of MPs to aquatic animals has increasingly become a severe environmental problem. In this study, we constructed a carp polystyrene microplastics (PS-MPs) exposure model to explore the damage and mechanism of PS-MPs exposure to carp myocardial tissue. The results of H&E, TUNEL, and AO/EB staining showed that PS-MPs exposure could induce inflammation, apoptosis, and necrosis in carp myocardial tissue and cardiomyocytes. In addition, our study explored the targeting relationship between PS-MPs and TLR4 and found that PS-MPs exposure could significantly increase the expression of TLR4 pathway-related factors. As the concentration of PS-MPs increased, the NF-κB pathway and inflammation-related factors increased dose-dependent. In addition, myocardial injury induced by exposure to PS-MPs was predominantly apoptotic, accompanied by necrosis. In short, our data suggest that PS-MPs cause damage to myocardial tissue via the TLR4\NF-κB pathway. The above findings enrich the theory of toxicological studies on PS-MPs and provide an essential reference for aquaculture.

MiR-15a-5p accelerated vascular smooth muscle cells viabilities and migratory abilities via targeting Bcl-2

Aortic dissection (AD) caused by the tear in the aortic wall threatens aorta, causing severe chest pain, syncope and even death. Fortunately, development of genetic technology provides promising approaches for AD treatment. To analyze impacts of miR-15a-5p on modulating cell viability and migratory ability of vascular smooth muscle cells (VSMCs). Ang II (0, 0.05 and 0.1 microM) treatment were applied for inducing inflammatory reactions of VSMCs. RNA expressions of miR-15a-5p with Bcl-2 was examined using RT-qPCR. CCK-8 and transwell evaluated cell viability and migratory ability, respectively. The binding about miR-15a-5p with Bcl-2 were detected by luciferase reporter assay. Western blot detected protein expressions of Bcl-2, MCP-1 and MMP-9. Ang II treatment not only accelerated VSMCs viability and migratory abilities, but also upregulated MCP-1 and MMP-9 protein expressions. MiR-15a-5p was detected to be promoted by Ang II. However, miR-15a-5p inhibitor decreased VSMC cell viability and migratory ability and suppressed protein expressions of MCP-1 and MMP-9. Bcl-2 was targeted and downregulated by miR-15a-5p. Nevertheless, high VSMC cell viability and migration caused by miR-15a-5p overexpression were hindered with overexpressed Bcl-2. MiR-15a-5p mimics also elevated MCP-1 and MMP-9 protein expressions, which were inhibited by Bcl-2 upregulation.

Transcription Factors Involved in the Development and Prognosis of Cardiac Remodeling

To compensate increasing workload, heart must work harder with structural changes, indicated by increasing size and changing shape, causing cardiac remodeling. However, pathological and unlimited compensated cardiac remodeling will ultimately lead to decompensation and heart failure. In the past decade, numerous studies have explored many signaling pathways involved in cardiac remodeling, but the complete mechanism of cardiac remodeling is still unrecognized, which hinders effective treatment and drug development. As gene transcriptional regulators, transcription factors control multiple cellular activities and play a critical role in cardiac remodeling. This review summarizes the regulation of fetal gene reprogramming, energy metabolism, apoptosis, autophagy in cardiomyocytes and myofibroblast activation of cardiac fibroblasts by transcription factors, with an emphasis on their potential roles in the development and prognosis of cardiac remodeling.

NF-κB inducible miR-30b-5p aggravates joint pain and loss of articular cartilage via targeting SIRT1-FoxO3a-mediated NLRP3 inflammasome

MicroRNAs (miRNAs) contribute to osteoarthritis (OA) development. Nevertheless, the function and mechanism of miR-30b-5p in OA are unclear. In the present article, we gauged the miR-30b-5p level in OA patients and analyzed its correlation with OA stages. Then, we conducted in-vivo and in-vitro gain-of-function assays to determine the function of miR-30b-5p, silent information regulator 2 homolog 1 (SIRT1) and Fox. Cell counting Kit-8 (CCK-8) assay, BrdU assay and flow cytometry were utilized to gauge cell viability and apoptosis of human chondrocyte (HC-A). The targeting association between miR-30b-5p and SIRT1 was validated through the dual-luciferase reporter assay and RNA immunoprecipitation (RIP) experiment. The results signified that miR-30b-5p was up-regulated in OA patients, OA rats and interleukin-1β (IL-1β)-induced chondrocytes. The higher miR-30b-5p expression brought about progressive stages of OA patients and enhanced levels of pro-inflammatory mediators in the synovial fluid. Functionally, overexpressing miR-30b-5p hampered cell viability, aggravated chondrocyte apoptosis and NLRP3 inflammasome activation induced by IL-1β, while down-regulating miR-30b-5p exerted the reverse effects. The in-vivo experiment exhibited that down-regulating miR-30b-5p improved joint pain and loss of articular cartilage in the rats with restrained inflammation and NLRP3 inflammasome activation. Mechanistically, miR-30b-5p targeted the 3'-non-translated region (3'UTR) of SIRT1, and miR-30b-5p was inducible with NF-κB phosphorylation enhancement. Overexpressing SIRT1 or inhibiting NF-κB relieved miR-30b-5p-induced apoptosis and NLRP3 inflammasome activation by promoting FoxO3a, while down-regulating SIRT1 or FoxO3a reversed miR-30b-5p-in-induced anti-inflammatory and apoptosis-suppressive effects. Collectively, NF-κB-induced miR-30b-5p modulates chondrocyte apoptosis and OA progression by regulating the SIRT1-FoxO3a-mediated NLRP3 inflammasome.

Cellular FADD-like IL-1β-converting enzyme-inhibitory protein attenuates myocardial ischemia/reperfusion injury via suppressing apoptosis and autophagy simultaneously

BACKGROUND AND AIMS

Myocardial ischemia/reperfusion injury (MI/RI) is a result of coronary revascularization, and often increases cell apoptosis and autophagy. Downregulated cellular FADD-like-IL-1β-converting enzyme-inhibitory protein (cFLIP) was associated with development of several myocardial diseases, whether overexpression of cFLIP can attenuate MI/RI remains unclear. This study aimed to determine the effects of cFLIP on apoptosis and autophagy in MI/RI.

METHODS AND RESULTS

Ischemia/reperfusion (I/R) rat model and hypoxia/reoxygenation (H/R) cardiomyocytes model were established. Both I/R injury and H/R injury down-regulated expression of two cFLIP isoforms (cFLIPL and cFLIPS), and instigated apoptosis and autophagy simultaneously. Overexpression of cFLIPL and/or cFLIPS led to a significant increase in cardiomyocytes viability in vitro, and also reduced the myocardial infarct volume in vivo, these changes were associated with suppressed apoptosis and autophagy. Mechanistically, overexpression of cFLIP significantly downregulated pro-apoptotic molecules (Caspase-3, -8, -9), and pro-autophagic molecules (Beclin-1 and LC3-II). Moreover, cFLIP significantly suppressed activity of NF-κB pathway to upregulate the expression of Bcl-2, which is the molecular of interplay of apoptosis and autophagy.

CONCLUSION

Overexpression of cFLIP significantly attenuated MI/RI both in vivo and vitro via suppression of apoptosis and lethal autophagy. cFLIP can suppress activity of NF-κB pathway, and further upregulated expression of Bcl-2.

Novel therapeutic strategies and perspectives for pancreatic cancer: Autophagy and apoptosis are key mechanisms to fight pancreatic cancer

Pancreatic cancer (PC) is the most lethal malignancy of the gastrointestinal tract. The poor prognosis of patients with PC is primarily due to lack of effective treatments against its progressive and metastatic behavior. Hence, figuring out the mechanisms underlying PC development and putting up with effective targeted therapies are of great significance to improve the prognosis of patients with PC. Apoptosis and autophagy serve to maintain tissue homoeostasis. Escaping from apoptosis or autophagy is one of the features of malignancy. PC is seriously resistant to autophagy and apoptosis, which explains its invasiveness and resistance to conventional treatment. Recently, several biological activities and pharmacological functions found in natural product extracts have been reported to inhibit PC progression. The current review focuses on understanding natural product extracts and their derivatives as one kind of novel treatments through affecting the apoptosis or autophagy in PC.

A meta-analysis of microRNA expression profiling studies in heart failure

Heart failure (HF) is a major consequence of many cardiovascular diseases with high rate of morbidity and mortality. Early diagnosis and prevention are hampered by the lack of informative biomarkers. The aim of this study was to perform a meta-analysis of the miRNA expression profiling studies in HF to identify novel candidate biomarkers or/and therapeutic targets. A comprehensive literature search of the PubMed for miRNA expression studies related to HF was carried out. The vote counting and robust rank aggregation meta-analysis methods were used to identify significant meta-signatures of HF-miRs. The targets of HF-miRs were identified, and network construction and gene set enrichment analysis (GSEA) were performed to identify the genes and cognitive pathways most affected by the dysregulation of the miRNAs. The literature search identified forty-five miRNA expression studies related to CHF. Shared meta-signature was identified for 3 up-regulated (miR-21, miR-214, and miR-27b) and 13 down-regulated (miR-133a, miR-29a, miR-29b, miR-451, miR-185, miR-133b, miR-30e, miR-30b, miR-1, miR-150, miR-486, miR-149, and miR-16-5p) miRNAs. Network properties showed miR-29a, miR-21, miR-29b, miR-1, miR-16, miR-133a, and miR-133b have the most degree centrality. GESA identified functionally related sets of genes in signaling and community pathways in HF that are the targets of HF-miRs. The miRNA expression meta-analysis identified sixteen highly significant HF-miRs that are differentially expressed in HF. Further validation in large patient cohorts is required to confirm the significance of these miRs as HF biomarkers and therapeutic targets.

Roles and regulatory mechanisms of miR-30b in cancer, cardiovascular disease, and metabolic disorders (Review)

MicroRNAs (miRNAs) are non-coding RNAs 21-23 nucleotides in length that regulate gene expression, and thereby modulate signaling pathways and protein synthesis in both physiological and pathogenic processes. miR-30b inhibits cell proliferation, migration, invasion and epithelial-mesenchymal transformation in multiple types of cancer. In addition to its role in several types of neoplasias, miR-30b has been shown to exhibit essential roles in cardiovascular and metabolic diseases. In the present review, an overview of the biological functions of miR-30b and its role in the pathogenesis of neoplastic, cardiovascular and metabolic diseases is provided. miR-30b is a potential candidate for clinical development as a diagnostic and prognostic biomarker, therapeutic agent and drug target. However, further research is required to elucidate its role in health and disease and to harness its potential clinical utility.

Characterization of Antiphospholipid Syndrome Atherothrombotic Risk by Unsupervised Integrated Transcriptomic Analyses

OBJECTIVE

Our aim was to characterize distinctive clinical antiphospholipid syndrome phenotypes and identify novel microRNA (miRNA)-mRNA-intracellular signaling regulatory networks in monocytes linked to cardiovascular disease. Approach and Results: Microarray analysis in antiphospholipid syndrome monocytes revealed 547 differentially expressed genes, mainly involved in inflammatory, cardiovascular, and reproductive disorders. Besides, this approach identified several genes related to inflammatory, renal, and dermatologic diseases. Functional analyses further demonstrated phosphorylation of intracellular kinases related to thrombosis and immune-mediated chronic inflammation. miRNA profiling showed altered expression of 22 miRNAs, enriched in pathways related to immune functions, cardiovascular disease, and autoimmune-associated pathologies. Unbiased integrated mRNA-miRNA analysis identified a signature of 9 miRNAs as potential modulators of 17 interconnected genes related to cardiovascular disease. The altered expression of that miRNA-mRNA signature was proven to be stable along time and distinctive of nonautoimmune thrombotic patients. Transfection studies and luciferase assays established the relationship between specific miRNAs and their identified target genes and proteins, along with their involvement in the regulation of monocytes procoagulant activity and cell adhesion. Correlation analyses showed relationship among altered miRNAs and their interconnected genes with aPL (antiphospholipid antibodies)-titers, along with microvascular endothelial dysfunction. In vitro studies demonstrated modulation in healthy monocytes by IgG-aPLs of several genes/miRNAs, which further intermediated downstream effects on endothelial function. The identified transcriptomic signature allowed the unsupervised division of three clusters of patients with antiphospholipid syndrome showing distinctive clinical profiles, mainly associated with their prothrombotic risk (thrombosis, autoantibody profile, cardiovascular risk factors, and atherosclerosis).

CONCLUSIONS

Extensive molecular profiling of monocytes in patients with primary antiphospholipid syndrome might help to identify distinctive clinical phenotypes, thus enabling new patients' tailored treatments.

Cadmium-Induced Renal Cell Toxicity Is Associated With MicroRNA Deregulation

Cadmium is an environmental pollutant well known for its nephrotoxic effects. Nevertheless, mechanisms underlying nephrotoxicity continue to be elucidated. MicroRNAs (miRNAs) have emerged in recent years as modulators of xenobiotic-induced toxicity. In this context, our study aimed at elucidating whether miRNAs are involved in renal proximal tubular toxicity induced by cadmium exposure. We showed that cadmium exposure, in 2 distinct renal proximal tubular cell models (renal proximal tubular epithelial cell [RPTEC]/human telomerase reverse transcriptase [hTERT] and human kidney-2), resulted in cytotoxicity associated with morphological changes, overexpression of renal injury markers, and induction of apoptosis and inflammation processes. Cadmium exposure also resulted in miRNA modulation, including the significant upregulation of 38 miRNAs in RPTEC/hTERT cells. Most of these miRNAs are known to target genes whose coding proteins are involved in oxidative stress, inflammation, and apoptosis, leading to tissue remodeling. In conclusion, this study provides a list of dysregulated miRNAs which may play a role in the pathophysiology of cadmium-induced kidney damages and highlights promising cadmium molecular biomarkers that warrants to be further evaluated.

Nonsense-mediated mRNA decay: The challenge of telling right from wrong in a complex transcriptome

The nonsense-mediated mRNA decay pathway selects and degrades its targets using a dense network of RNA-protein and protein-protein interactions. Together, these interactions allow the pathway to collect copious information about the translating mRNA, including translation termination status, splice junction positions, mRNP composition, and 3'UTR length and structure. The core NMD machinery, centered on the RNA helicase UPF1, integrates this information to determine the efficiency of decay. A picture of NMD is emerging in which many factors contribute to the dynamics of decay complex assembly and disassembly, thereby influencing the probability of decay. The ability of the NMD pathway to recognize mRNP features of diverse potential substrates allows it to simultaneously perform quality control and regulatory functions. In vertebrates, increased transcriptome complexity requires balance between these two functions since high NMD efficiency is desirable for maintenance of quality control fidelity but may impair expression of normal mRNAs. NMD has adapted to this challenge by employing mechanisms to enhance identification of certain potential substrates, while using sequence-specific RNA-binding proteins to shield others from detection. These elaborations on the conserved NMD mechanism permit more sensitive post-transcriptional gene regulation but can have severe deleterious consequences, including the failure to degrade pathogenic aberrant mRNAs in many B cell lymphomas. This article is categorized under: RNA Evolution and Genomics > RNA and Ribonucleoprotein Evolution RNA Interactions with Proteins and Other Molecules > Protein-RNA Interactions: Functional Implications RNA Turnover and Surveillance > Turnover/Surveillance Mechanisms.

GP73, a novel TGF-β target gene, provides selective regulation on Smad and non-Smad signaling pathways

Increased GP73 expression in hepatocytes from patients with acute hepatitis, through disease progression to cirrhosis and chronic liver disease suggests that progressive tissue remodeling and fibrogenesis are driving forces for GP73 upregulation. Nevertheless, details about regulation of GP73 expression and its biological functions remain elusive and await further characterization. In this study, we demonstrate that GP73 is a direct target of TGF-β1 transcriptional regulation. Its induced expression inhibits TGF-β-Smad mediated growth suppression. On the other hand, elevated GP73 results in upregulation of ERK/Akt signaling induced by TGF-β1. Mechanistically, upregulation of lipid raft and caveolae-1 induced by GP73 overexpression mediates its regulatory effect on TGF-β1 signaling. Notably, lipid raft expression is elevated in HCC tumors and tissues with higher GP73 expression yield more intensive Flotillin staining. Our results establish the linkage between GP73 and TGF-β signaling, indicating that GP73 may promote HCC tumorigenesis by selectively regulating TGF-β signaling through lipid raft modulation.

hnRNP L-dependent protection of normal mRNAs from NMD subverts quality control in B cell lymphoma

The human nonsense-mediated mRNA decay pathway (NMD) performs quality control and regulatory functions within complex post-transcriptional regulatory networks. In addition to degradation-promoting factors, efficient and accurate detection of NMD substrates involves proteins that safeguard normal mRNAs. Here, we identify hnRNP L as a factor that protects mRNAs with NMD-inducing features including long 3'UTRs. Using biochemical and transcriptome-wide approaches, we provide evidence that the susceptibility of a given transcript to NMD can be modulated by its 3'UTR length and ability to recruit hnRNP L. Integrating these findings with the previously defined role of polypyrimidine tract binding protein 1 in NMD evasion enables enhanced prediction of transcript susceptibility to NMD. Unexpectedly, this system is subverted in B cell lymphomas harboring translocations that produce BCL2:IGH fusion mRNAs. CRISPR/Cas9 deletion of hnRNP L binding sites near the BCL2 stop codon reduces expression of the fusion mRNAs and induces apoptosis. Together, our data indicate that protection by hnRNP L overrides the presence of multiple 3'UTR introns, allowing these aberrant mRNAs to evade NMD and promoting BCL2 overexpression and neoplasia.

Deciphering Non-coding RNAs in Cardiovascular Health and Disease

After being long considered as “junk” in the human genome, non-coding RNAs (ncRNAs) currently represent one of the newest frontiers in cardiovascular disease (CVD) since they have emerged in recent years as potential therapeutic targets. Different types of ncRNAs exist, including small ncRNAs that have fewer than 200 nucleotides, which are mostly known as microRNAs (miRNAs), and long ncRNAs that have more than 200 nucleotides. Recent discoveries on the role of ncRNAs in epigenetic and transcriptional regulation, atherosclerosis, myocardial ischemia/reperfusion (I/R) injury and infarction (MI), adverse cardiac remodeling and hypertrophy, insulin resistance, and diabetic cardiomyopathy prompted vast interest in exploring candidate ncRNAs for utilization as potential therapeutic targets and/or diagnostic/prognostic biomarkers in CVDs. This review will discuss our current knowledge concerning the roles of different types of ncRNAs in cardiovascular health and disease and provide some insight on the cardioprotective signaling pathways elicited by the non-coding genome. We will highlight important basic and clinical breakthroughs that support employing ncRNAs for treatment or early diagnosis of a variety of CVDs, and also depict the most relevant limitations that challenge this novel therapeutic approach.

MicroRNA-30b protects myocardial cell function in patients with acute myocardial ischemia by targeting plasminogen activator inhibitor-1

The aim of the present study was to determine the expression of plasminogen activator inhibitor-1 (PAI-1) and microRNA (miR)-30b in the blood of patients with acute myocardial ischemia (AMI) and in the blood and myocardial tissue of mice with AMI. In addition, the present study aimed to identify the mechanism of action of miR-30b in AMI. A total of 36 patients with AMI were included in the present study and 28 healthy subjects were included as a control. Peripheral blood was collected from all subjects. For animal experiments, mice in the AMI group received an intraperitoneal injection of pituitrin (20 U/kg), whereas mice in the negative control group received an intraperitoneal injection of the same volume of saline. Blood and myocardial tissue was collected from all mice for analysis. Reverse transcription-quantitative polymerase chain reaction was performed to determine the expression of PAI-1 mRNA and miR-30b in the serum and myocardial tissue. An enzyme-linked immunosorbent assay was performed to measure the expression of PAI-1 protein in the serum of humans and mice, whereas western blotting was performed to determine the expression of PAI-1 protein in mouse myocardial tissue. Catalase, glutathione peroxidase and superoxide dismutase activity was measured using an automatic biochemical analyzer. A dual luciferase assay was performed to identify the interactions between PAI-1 mRNA and miR-30b. The results indicated that patients with AMI have higher PAI-1 levels and lower miR-30b expression in the peripheral blood compared with healthy subjects. AMI damaged the myocardium tissue of mice and reduced catalase, glutathione peroxidase and superoxide dismutase activity. Mice that have undergone AMI exhibit increased PAI-1 levels but decreased miR-30b expression in the peripheral blood and myocardial tissues. It was also demonstrated that miR-30b is able to bind to the 3'-untranslated region of PAI-1 mRNA to regulate its expression. The present study demonstrates that patients with AMI exhibit decreased miR-30b expression and elevated PAI-1 expression in the peripheral blood. miR-30b may therefore inhibit the damage to myocardial cells that occurs following AMI and protect myocardial cell function by targeting PAI-1 expression.

B7-Homolog 4 Promotes Epithelial-Mesenchymal Transition and Invasion of Bladder Cancer Cells via Activation of Nuclear Factor-κB

B7-homolog 4 (B7-H4), a member of the B7 family of costimulatory molecules, has been reported to be upregulated in urothelial cell carcinoma. This study was conducted to explore the biological role of B7-H4 in the aggressiveness of bladder cancer and the associated molecular mechanism. We found that the mRNA and protein levels of B7-H4 were significantly greater in bladder cancer cell lines than in SV-HUC-1 (normal human urothelial cells). Overexpression of B7-H4 significantly promoted bladder cancer cell migration and invasion, whereas knockdown of B7-H4 exerted an opposite effect. However, the growth of bladder cancer cells was not altered by B7-H4 overexpression or knockdown. Overexpression of B7-H4 promoted epithelial–mesenchymal transition (EMT), as evidenced by decreased E-cadherin and increased vimentin expression. The EMT inducers Twist1 and Snail were upregulated by B7-H4 overexpression and downregulated by B7-H4 silencing. Mechanistically, overexpression of B7-H4 induced the activation of NF-κB signaling. Pharmacological inhibition of NF-κB partially prevented B7-H4-mediated bladder cancer cell invasion. Taken together, B7-H4/NF-κB signaling is involved in the EMT and invasion of bladder cancer cells and represents a new candidate target for the treatment of bladder cancer.

Rapid and label-free fluorescence bioassay for microRNA based on exonuclease III-assisted cycle amplification

A new assay for the rapid and simple detection of microRNA based on G-quadruplex and Exonuclease III (ExoIII) dual signal amplification was constructed.

Sporamin induces apoptosis and inhibits NF-κB activation in human pancreatic cancer cells

Sporamin, a Kunitz-type trypsin inhibitor (TI) from sweet potato tuberous roots, has demonstrated anti-tumor activity through poorly defined mechanisms. Furthermore, the effects of sporamin on pancreatic cancer have not been explored. Herein, we studied the effects of sporamin on two human pancreatic cancer cell lines, PANC-1 and BxPC-3. Sporamin significantly inhibited the cell viability and proliferation activity and induced apoptosis in PANC-1 and BxPC-3 cells. Consistently, in sporamin-treated PANC-1 and BxPC-3 cells, the anti-apoptotic proteins Bcl-2 and Bcl-XL were downregulated and the pro-apoptotic protein Bax was upregulated. Moreover, nuclear factor kappa B activation and IκBα phosphorylation were inhibited, and total IκBα expression was increased in sporamin-treated PANC-1 and BxPC-3 cells. Thus, our results suggest that the anti-tumor effects of sporamin in pancreatic cancer cells might result partly from induction of apoptosis by downregulating nuclear factor kappa B pathway.

The Role of MicroRNAs in Myocardial Infarction: From Molecular Mechanism to Clinical Application

MicroRNAs (miRNAs) are a class of small single-stranded and highly conserved non-coding RNAs, which are closely linked to cardiac disorders such as myocardial infarction (MI), cardiomyocyte hypertrophy, and heart failure. A growing number of studies have demonstrated that miRNAs determine the fate of the heart by regulating cardiac cell death and regeneration after MI. A deep understanding of the pathophysiology of miRNA dependent regulatory pathways in these processes is required. The role of miRNAs as diagnostic, prognostic, and therapeutic targets also needs to be explored in order to utilize them in clinical settings. This review summarizes the role of miRNAs in myocardial infarction and focuses mainly on their influence on cardiomyocyte regeneration and cell death including apoptosis, necrosis, and autophagy. In addition, the targets of pro- and anti-MI miRNAs are comparatively described. In particular, the possibilities of miRNA-based diagnostic and therapeutic strategies for myocardial infarction are discussed in this review.

Overview of MicroRNAs in Cardiac Hypertrophy, Fibrosis, and Apoptosis

MicroRNAs (miRNAs) are non-coding RNAs that play essential roles in modulating the gene expression in almost all biological events. In the past decade, the involvement of miRNAs in various cardiovascular disorders has been explored in numerous in vitro and in vivo studies. In this paper, studies focused upon the discovery of miRNAs, their target genes, and functionality are reviewed. The selected miRNAs discussed herein have regulatory effects on target gene expression as demonstrated by miRNA/3′ end untranslated region (3′UTR) interaction assay and/or gain/loss-of-function approaches. The listed miRNA entities are categorized according to the biological relevance of their target genes in relation to three cardiovascular pathologies, namely cardiac hypertrophy, fibrosis, and apoptosis. Furthermore, comparison across 86 studies identified several candidate miRNAs that might be of particular importance in the ontogenesis of cardiovascular diseases as they modulate the expression of clusters of target genes involved in the progression of multiple adverse cardiovascular events. This review illustrates the involvement of miRNAs in diverse biological signaling pathways and provides an overview of current understanding of, and progress of research into, of the roles of miRNAs in cardiovascular health and disease.

miR-30-5p Regulates Muscle Differentiation and Alternative Splicing of Muscle-Related Genes by Targeting MBNL

MicroRNAs (miRNAs), a class of single stranded, small (~22 nucleotides), non-coding RNAs, play an important role in muscle development. We focused on the role of the miR-30-5p family during bovine muscle development from previous high-throughput sequencing results and analyzed their expression profiles. MHC and MyoG mRNAs expression as well as their proteins were suppressed in differentiated C2C12 cells, suggesting the importance of miR-30-5p in muscle development. MBNL, the candidate target of miR-30-5p, is an alternative splicing regulation factor. MBNL1 and MBNL3 have opposite effects on muscle differentiation. Our results confirmed that miR-30a-5p and miR-30e-5p repress the expression of MBNL1, MBNL2 and MBNL3, whereas miR-30b-5p inhibits MBNL1 and MBNL2 expression. This provides direct evidence that MBNL expression can be flexibly regulated by miR-30-5p. Previous studies showed that MBNL1 promotes exon inclusion of two muscle-related genes (Trim55 and INSR). Through RNA splicing studies, we found that miR-30-5p had an effect on their alternative splicing, which means miR-30-5p via MBNL1 could be integrated into muscle signaling pathways in which INSR or Trim55 are located. In conclusion, miR-30-5p could inhibit muscle cell differentiation and regulate the alternative splicing of Trim55 and INSR by targeting MBNL. These results promote the understanding of the function of miRNAs in muscle development.

miR-101a and miR-30b contribute to inflammatory cytokine-mediated β-cell dysfunction

Inflammatory cytokines have a critical role in the progressive deterioration of pancreatic β-cell function and development of type 1 diabetes. Prolonged exposure of β-cells to inflammatory cytokines results in gene expression modifications, leading to loss of β-cell function. MicroRNAs (miRNAs) are small non-coding RNAs acting as key regulators of gene expression. Here, we demonstrate that miR-101a and miR-30b are key players in cytokine-mediated β-cell dysfunction. We found that IL-1β induces an increase in miR-101a and miR-30b in MIN6 cells, and that the two miRNAs participate in β-cell dysfunction, including decreased insulin content, gene expression, and increased β-cell death. miR-101a and miR-30b reduce proinsulin expression and insulin content by directly targeting the transcriptional factor Neurod1. In addition, β-cell apoptosis mediated by miR-101a and miR-30b is associated with diminished expression level of the antiapoptotic protein Bcl2. Moreover, we show that miR-101a causes an impairment in glucose-induced insulin secretion by decreasing the expression of the transcription factor Onecut2. Taken together, our findings suggest that changes in the levels of miR-101a and miR-30b contribute to cytokine-mediated β-cell dysfunction occurring during the development and progression of type 1 diabetes.

Expression of early growth response 1 affects miR-106a/signal transducer and activator of transcription 3 regulating cognitive impairment in ovariectomized mice

OBJECTIVE

This study aims to investigate the effects of early growth response 1 (Egr1) on miR-106a/signal transducer and activator of transcription 3 (STAT3) regulating cognitive impairment in an ovariectomy model.

METHODS

Using the Morris water maze test, we assessed escape latency and time spent in a quadrant among mice at 6, 8, and 12 weeks after ovariectomy and their age-matched controls (n = 15 each group). Egr1, miR-106a, and STAT3 messenger RNA expression (n = 7) in the hippocampus and cortex of mice at 6, 8, and 12 weeks after ovariectomy was detected by quantitative real-time polymerase chain reaction, whereas Egr1, phospho-STAT3 (p-STAT3), and STAT3 protein expression (n = 8) was evaluated by Western blot analysis. Moreover, alterations in miR-106a and STAT3 expression were investigated in neuroblastoma (SH-SY5Y) cells transfected with a human Egr1 interference fragment (si-Egr1) or an Egr1-overexpressing plasmid (GV141-Egr1), respectively.

RESULTS

Escape latency was significantly increased and time spent in a platform quadrant was reduced in mice at 12 weeks after ovariectomy compared with age-matched controls. Egr1 and miR-106a expression was obviously increased in the hippocampus and cortex at 12 weeks after ovariectomy, whereas STAT3 levels were decreased compared with 12-week controls. After SH-SY5Y cell transfection with the si-Egr1 fragment, miR-106a levels decreased and STAT3/p-STAT3 levels increased, whereas cotransfection of the miR-106a mimic caused a significant decrease in STAT3 levels. MiR-106a messenger RNA expression was significantly increased and STAT3/p-STAT3 protein levels were decreased by Egr1 overexpression, whereas simultaneous transfection with the miR-106a inhibitor inhibited alterations in STAT3 levels.

CONCLUSIONS

This study suggests that Egr1 decreases STAT3 expression via miR-106a in ovariectomized mice with cognitive impairment, indicating that Egr1 represents a potential target for therapeutic intervention in postmenopausal cognitive decline.

E2F1-regulated miR-30b suppresses Cyclophilin D and protects heart from ischemia/reperfusion injury and necrotic cell death

Cardiovascular disease remains the leading cause of morbidity and mortality worldwide. Cell death is a hallmark characteristic of various cardiac diseases, including myocardial infarction and heart failure. Emerging evidences suggest that necrosis is programmed and is one of the main forms of cell death in the pathological process in cardiac diseases. However, the molecular components regulating programmed necrosis in heart remain largely unidentified. Here we report that miR-30b, Cyclophilin D (CypD) and E2F1 constitute an axis that regulates necrosis. The results show that knockdown of CypD attenuated necrosis in the cellular model and also myocardial infarction in the animal model. miR-30b suppresses the translation of CypD and thus inhibits CypD-mediated necrotic cell death in cardiomyocytes. Cardiac-specific miR-30b transgenic mice exhibit reduced necrosis and myocardial infarct size upon ischemia/reperfusion (I/R) injury. Further, we identify that E2F1 transcriptionally represses miR-30b expression. Knockdown of E2F1 in cardiomyocytes inhibits necrotic cell death, and E2F1 knockout mice show reduced necrosis and myocardial infarct size upon I/R. Our present study identifies a novel signaling pathway composed of E2F1, miR-30b and CypD that regulates myocardial necrosis. This discovery will not only provide de novo regulators in the necrotic process but will also shed new light on the effective therapy of myocardial infarction and heart failure.

MiRNA and TF co-regulatory network analysis for the pathology and recurrence of myocardial infarction

Myocardial infarction (MI) is a leading cause of death in the world and many genes are involved in it. Transcription factor (TFs) and microRNAs (miRNAs) are key regulators of gene expression. We hypothesized that miRNAs and TFs might play combinatory regulatory roles in MI. After collecting MI candidate genes and miRNAs from various resources, we constructed a comprehensive MI-specific miRNA-TF co-regulatory network by integrating predicted and experimentally validated TF and miRNA targets. We found some hub nodes (e.g. miR-16 and miR-26) in this network are important regulators, and the network can be severed as a bridge to interpret the associations of previous results, which is shown by the case of miR-29 in this study. We also constructed a regulatory network for MI recurrence and found several important genes (e.g. DAB2, BMP6, miR-320 and miR-103), the abnormal expressions of which may be potential regulatory mechanisms and markers of MI recurrence. At last we proposed a cellular model to discuss major TF and miRNA regulators with signaling pathways in MI. This study provides more details on gene expression regulation and regulators involved in MI progression and recurrence. It also linked up and interpreted many previous results.

Protective effect of microRNA-30b on hypoxia/reoxygenation-induced apoptosis in H9C2 cardiomyocytes

We examined the protective role of microRNA-30b (miR-30b) in ischemia-reperfusion (I/R)-induced injury in rat H9C2 cardiomyocytes. H9C2 cells were subjected to hypoxia-reoxygenation (H/R) treatment to simulate ischemia-reperfusion (I/R) injury. H9C2 cells were divided into: vehicle control (VC) group; scrambled inhibitors (INC) group; scrambled mimics (MNC) group; H/R+VC group; H/R+INC group; H/R+mimics group. H/R induced apoptosis was detected by flow cytometry and the pathways involved in miR-30b-mediated protection were examined by analyzing the expression of miR-30b, Bcl-2, Bax, Caspase-3, KRAS, p-AKT and total AKT in H9C2 cells. Overexpression of miR-30b mimic (H/R+mimics group) significantly increased Bcl-2 and Bcl-2/Bax levels and decreased Bax and Caspase-3 levels, compared with the H/R+VC group (all P<0.05). Consistent with this, the apoptosis rate was significantly decreased in the H/R+mimics group (P<0.05) compared with the H/R+VC group. Western blot analysis revealed that overexpression of miR-30b mimic resulted in significantly increase in AKT activation and decreased KRAS, compared to the H/R+VC group (both P<0.05). In conclusion, the H/R induced apoptosis decreased miR-30b expression, but over-expression of miR-30b inhibited H/R induced apoptosis. The observed miR-30b-mediated protection against H/R induced apoptosis involved the upregulation of Ras-PI3K-Akt pathway.

miRNA-30 family inhibition protects against cardiac ischemic injury by regulating cystathionine-γ-lyase expression

AIMS

Myocardial infarction (MI) is a leading cause of death globally. MicroRNAs (miRNAs) have been identified as a novel class of MI injury regulators. Hydrogen sulfide (H2S) is a gaseous signaling molecule that regulates cardiovascular function. The purpose of this study was to explore the role of the miR-30 family in protecting against MI injury by regulating H2S production.

RESULTS

The expression of miR-30 family was upregulated in the murine MI model as well as in the primary cardiomyocyte hypoxic model. However, the cystathionine-γ-lyase (CSE) expression was significantly decreased. The overexpression of miR-30 family decreased CSE expression, reduced H2S production, and then aggravated hypoxic cardiomyocyte injury. In contrast, silencing the whole miR-30 family can protect against hypoxic cell injury by elevating CSE and H2S level. Nonetheless, the protective effect was abolished by cotransfecting with CSE-siRNA. Systemic delivery of a locked nucleic acid (LNA)-miR-30 family inhibitor correspondingly increased CSE and H2S level, then reduced infarct size, decreased apoptotic cell number in the peri-infarct region, and improved cardiac function in response to MI. However, these cardioprotective effects were absent in CSE knockout mice. MiR-30b overexpression in vivo aggravated MI injury because of H2S reduction, and this could be rescued by S-propargyl-cysteine (SPRC), which is a novel modulator of CSE, or further exacerbated by propargylglycine (PAG), which is a selective inhibitor of CSE.

INNOVATION AND CONCLUSION

Our findings reveal a novel molecular mechanism for endogenous H2S production in the heart at the miRNA level and demonstrate the therapeutic potential of miR-30 family inhibition for ischemic heart diseases by increasing H2S production.

MicroRNAs and biological functions of hepatic stellate cells

MicroRNAs (miRNAs) are single-stranded, 18-24 nucleotide long, non-coding RNA molecules which are involved in virtually every cellular process including proliferation, differentiation and apoptosis by specifically interacting with the mRNA and regulating the expression of genes. Recently it has been found that miRNAs cooperate with transforming growth factor (TGF-β), nuclear factor kappa B (NF-κB), tumor necrosis factor α (TNF-α) and other cytokines, and form complex "network" signaling pathways to influence the activation, proliferation, migration and apoptosis of hepatic stellate cells (HSCs), suggesting that miRNAs may regulate biological behaviors of HSCs via various signal transduction pathways, and have a great influence on the development of hepatic fibrosis. This article will review the impact of miRNAs on the biological functions of HSCs via different signal transduction pathways.

MicroRNAs affect BCL-2 family proteins in the setting of cerebral ischemia

The BCL-2 family is centrally involved in the mechanism of cell death after cerebral ischemia. It is well known that the proteins of the BCL-2 family are key regulators of apoptosis through controlling mitochondrial outer membrane permeabilization. Recent findings suggest that many BCL-2 family members are also directly involved in controlling transmission of Ca(2+) from the endoplasmic reticulum (ER) to mitochondria through a specialization called the mitochondria-associated ER membrane (MAM). Increasing evidence supports the involvement of microRNAs (miRNAs), some of them targeting BCL-2 family proteins, in the regulation of cerebral ischemia. In this mini-review, after highlighting current knowledge about the multiple functions of BCL-2 family proteins and summarizing their relationship to outcome from cerebral ischemia, we focus on the regulation of BCL-2 family proteins by miRNAs, especially miR-29 which targets multiple BCL-2 family proteins.