Non-coding RNA in Ischemic and Non-ischemic Cardiomyopathy

Causal Relationship Between Immune Cells/Cytokines and Dilated Cardiomyopathy

To date, whether there is any causal relationship between dilated cardiomyopathy (DCM) and the changes in the levels/expression of immune cells/cytokines is still unclear. This study aimed to investigate the causal relationship between the levels of various types of immune cells/cytokines and DCM. Herein, two-sample Mendelian randomization (MR) (TSMR) using R software was conducted. Single nucleotide polymorphisms (SNPs) related to the levels of various types of immune cells/cytokines and DCM were screened based on the genome-wide association studies (GWAS) obtained from open-source databases. The TSMR was conducted using inverse variance weighted (IVW), method, MR-Egger regression, weighted median method, and simple estimator based on mode to explore the causal association between the levels of each immune cell/cytokine and DCM. Sensitivity analysis was conducted using MR-Egger regression and a leave-one-out sensitivity test. A total of 1816 SNPs related to host immune status and DCM were identified. The IVW results showed a relationship between DCM and the circulating levels of basophils/eosinophils, total eosinophils-basophils, lymphocytes, and C-reactive protein (CRP). Increased lymphocytes levels (odds ratio (OR) = 0.91, 95% confidence interval (CI): 0.84-0.97, P = 0.005) were seen as protective against DCM, whereas increased basophil (OR = 1.18, 95% CI: 1.04-1.33, P = 0.022), eosinophil (OR = 1.1, 95% CI: 1.03-1.17, P = 0.007), eosinophil-basophil (OR = 1.09, 95% CI: 1.02-1.17, P = 0.014), and CRP (OR = 1.1, 95% CI: 1.03-1.18, P = 0.013) levels were associated with an increased risk of DCM. These analyses revealed that there may be a relationship between immune cells/select cytokine status and the onset of DCM. Future studies are required to further validate these outcomes in animal models and clinical trials.

Searching for Intrinsic Causality between Colonic Dysbiosis and Non-Ischemic Cardiomyopathy: A Mendelian Randomization-Based Analysis

Objective: Little is known about gut microbiota (GM) and cardiomyopathy. Their causal relationship was explored using two-sample Mendelian randomization (TSMR) performed by R software. Methods: The single nucleotide polymorphisms (SNPs) were further screened based on the genome-wide association studies (GWAS) of gut microbiota and cardiomyopathy obtained from an open database. TSMR was performed using an MR-Egger regression, simple estimator based on mode, weighted median method, inverse variance weighted (IVW), weighted estimator and CML-MA-BIC to explore the causal association. And the sensitivity analysis was carried out using an MR-Egger regression and the leave-one-out sensitivity test. Results: As for 211 GM taxa, IVW results confirmed that the class Actinobacteria (OR = 0.81, p = 0.021) and genus Coprobacter (OR = 0.85, p = 0.033) were protective factors for cardiomyopathy. The phylum Firmicutes (OR = 0.87, p < 0.01), family Acidaminococcaceae (OR = 0.89, p < 0.01), genus Desulfovibrio (OR = 0.92, p = 0.030) and genus Prevotella9 (OR = 0.93, p = 0.029) were protective factors for ischemic cardiomyopathy. The family Rhodospirillaceae (OR = 1.06, p = 0.036) and genus Turicibacter (OR = 1.09, p = 0.019) were risk factors for ischemic cardiomyopathy. The genus Olsenella (OR = 0.91, p = 0.032) was a protective factor for non-ischemic cardiomyopathy. The order Rhodospirillales (OR = 1.14, p = 0.024), family Rikenellaceae (OR = 1.21, p = 0.012) and genus Gordonibacter (OR = 1.12, p = 0.019) were risk factors for non-ischemic cardiomyopathy. The robustness of MR results was reflected in the heterogeneity (p > 0.05) and pleiotropy (p > 0.05) analyses. Conclusions: A potential causal relationship of cardiomyopathy with some GM taxa has been confirmed in the current study.

MicroRNA-574 regulates FAM210A expression and influences pathological cardiac remodeling

Aberrant expression of mitochondrial proteins impairs cardiac function and causes heart disease. The mechanism of regulation of mitochondria encoded protein expression during cardiac disease, however, remains underexplored. Here, we show that multiple pathogenic cardiac stressors induce the expression of miR-574 guide and passenger strands (miR-574-5p/3p) in both humans and mice. miR-574 knockout mice exhibit severe cardiac disorder under different pathogenic cardiac stresses while miR-574-5p/3p mimics that are delivered systematically using nanoparticles reduce cardiac pathogenesis under disease insults. Transcriptomic analysis of miR-574-null hearts uncovers family with sequence similarity 210 member A (FAM210A) as a common target mRNA of miR-574-5p and miR-574-3p. The interactome capture analysis suggests that FAM210A interacts with mitochondrial translation elongation factor EF-Tu. Manipulating miR-574-5p/3p or FAM210A expression changes the protein expression of mitochondrial-encoded electron transport chain (ETC) genes but not nuclear-encoded mitochondrial ETC genes in both human AC16 cardiomyocyte cells and miR-574-null murine hearts. Together, we discovered that miR-574 regulates FAM210A expression and modulates mitochondrial-encoded protein expression, which may influence cardiac remodeling in heart failure.

Non-coding RNAs in cardiomyocyte proliferation and cardiac regeneration: Dissecting their therapeutic values

Cardiovascular diseases are associated with high incidence and mortality, contribute to disability and place a heavy economic burden on countries worldwide. Stimulating endogenous cardiomyocyte proliferation and regeneration has been considering as a key to repair the injured heart caused by ischaemia. Emerging evidence has proved that non‐coding RNAs participate in cardiac proliferation and regeneration. In this review, we focus on the observation and mechanism that microRNAs (or miRNAs), long non‐coding RNAs (or lncRNAs) and circular RNA (or circRNAs) regulate cardiomyocyte proliferation and regeneration to repair a damaged heart. Furthermore, we highlight the potential therapeutic role of some non‐coding RNAs used in stimulating CMs proliferation. Finally, perspective on the development of non‐coding RNAs therapy in cardiac regeneration is presented.

The functions of LncRNA in the heart

Cardiovascular disease is a major cause of death and disability worldwide. Recently, increasing evidence has demonstrated that various lncRNAs play critical roles in the pathogenesis of cardiovascular diseases, including myocardial ischemia and reperfusion (I/R) injury. LncRNAs are transcripts longer than 200 nucleotides. They are considered a class of dynamic noncoding RNAs known to be involved in physiological and pathological conditions with regulatory and structural roles in numerous biological processes, including genomic imprinting, epigenetic regulation, cell proliferation, development, aging and apoptosis. They are emerging as potential key regulators of a variety of cardiovascular diseases. However, the roles of lncRNAs in the heart function remain largely unknown. The purpose of this review was to summarize the functions of lncRNAs in the heart and discuss the challenges and possible strategies of lncRNA research for cardiovascular disease.

A susceptibility biomarker identification strategy based on significantly differentially expressed ceRNA triplets for ischemic cardiomyopathy

Ischemic cardiomyopathy (ICM) is a common human heart disease that causes death. No effective biomarkers for ICM could be found in existing databases, which is detrimental to the in-depth study of this disease. In the present study, ICM susceptibility biomarkers were identified using a proposed strategy based on RNA-Seq and miRNA-Seq data of ICM and normal samples. Significantly differentially expressed competing endogenous RNA (ceRNA) triplets were constructed using permutation tests and differentially expressed mRNAs, miRNAs and lncRNAs. Candidate ICM susceptible genes were screened out as differentially expressed genes in significantly differentially expressed ceRNA triplets enriched in ICM-related functional classes. Finally, eight ICM susceptibility genes and their significantly correlated lncRNAs with high classification accuracy were identified as ICM susceptibility biomarkers. These biomarkers would contribute to the diagnosis and treatment of ICM. The proposed strategy could be extended to other complex diseases without disease biomarkers in public databases.

Genome Editing for the Understanding and Treatment of Inherited Cardiomyopathies

Cardiomyopathies are diseases of heart muscle, a significant percentage of which are genetic in origin. Cardiomyopathies can be classified as dilated, hypertrophic, restrictive, arrhythmogenic right ventricular or left ventricular non-compaction, although mixed morphologies are possible. A subset of neuromuscular disorders, notably Duchenne and Becker muscular dystrophies, are also characterized by cardiomyopathy aside from skeletal myopathy. The global burden of cardiomyopathies is certainly high, necessitating further research and novel therapies. Genome editing tools, which include zinc finger nucleases (ZFNs), transcription activator-like effector nucleases (TALENs) and clustered regularly interspaced short palindromic repeats (CRISPR) systems have emerged as increasingly important technologies in studying this group of cardiovascular disorders. In this review, we discuss the applications of genome editing in the understanding and treatment of cardiomyopathy. We also describe recent advances in genome editing that may help improve these applications, and some future prospects for genome editing in cardiomyopathy treatment.

Blocking lncRNA MIR155HG/miR-155-5p/-3p inhibits proliferation, invasion and migration of clear cell renal cell carcinoma

This study aimed to investigate the effect of blocking the MIR155HG/miR-155-5p/-3p axis on proliferation, invasion and migration of clear cell renal cell carcinoma. RT-qPCR was used to detect the expression of MIR155HG, miR-155-5p, miR-155-3p in clear cell renal cell carcinoma cell lines. To study the effects of blocking LncRNA MIR155HG and interfering with miR-155-5p and miR-155-3p on the biological function. The g proliferation of tumor was detected by CCK-8, and the cell invasion and migration abilities were detected by wound healing and transwell experiments. Western blot analyzed protein levels of KI67, PCNA, MMP2 and MMP9. Furthermore, TargetScan and miRDB were used to predict the co-target gene of miR-155-3p and miR-155-5p, and the functional analysis of co-target genes was performed using the DAVID. In the current research, the expression of MIR155HG was increased in ccRCC. Interference of MIR155HG inhibited the cellular functions of ccRCC cells, which was reversed by overexpression of miR-155-3p and miR-155-5p. In addition, MIR155HG interference repressed the expression of miR-155-5p and miR-155-3p in ccRCCs, while inhibition of miR-155-5p and miR-155-3p restrained the proliferation, invasion and migration of ccRCCs. Bioinformatics software analysis showed 13 co-targeting genes of miR-155-3p and miR-155-5p. Functional analysis presented that the target genes of miR-31-3p were involved in numerous of biochemical processes and pathways.Blocking lncRNA MIR155HG/miR-155-5p/-3p inhibits proliferation, invasion and migration of renal clear cell carcinoma, which provided a new method for early diagnosis and precise treatment of ccRCC.

MiR-421 inhibition protects H9c2 cells against hypoxia/reoxygenation-induced oxidative stress and apoptosis by targeting Sirt3

BACKGROUND

MicroRNAs (miRNAs) are involved in myocardial ischemia-reperfusion injury. miRNA-421 (miR-421) plays a significant role in the initiation of apoptosis and myocardial infarction. However, the molecular regulation of miR-421 in myocardial ischemia-reperfusion injury requires further elucidation.

METHODS

An in vitro hypoxia/reoxygenation model was established, and the expression levels of miR-421 and Sirtuin-3 (Sirt3) in H9c2 cells were quantified using quantitative real-time polymerase chain reaction. Flow cytometry was employed to measure the effects of miR-421 on myocardial apoptosis induced by hypoxia/reoxygenation. The activity of lactate dehydrogenase and superoxide dismutase and levels of malondialdehyde were measured. The binding sites of miR-421 on Sirt3 were predicted using TargetScan software. A luciferase reporter assay was used to validate the direct targeting of Sirt3 with miR-421. Protein expression levels of Sirt3 and its downstream proteins were evaluated using Western blot analysis.

RESULTS

Exposure of H9c2 cells to hypoxia/reoxygenation led to increased apoptosis, levels of malondialdehyde and lactate dehydrogenase, and decreased levels of superoxide dismutase. miR-421 knockdown resulted in decreased apoptosis, levels of lactate dehydrogenase and malondialdehyde, and increased superoxide dismutase levels in H9c2 cells. Hypoxia/reoxygenation significantly decreased the relative expression levels of Sirt3. Down-regulation of Sirt3 resulted from overexpression of miR-421, which directly targeted Sirt3. Knockdown of miR-421 up-regulated Sirt3 expression, inhibited activation of the Jun N-terminal kinase/activator protein 1 pathway and caspase 9/3-dependent cell death.

CONCLUSION

The miR-421-Sirt3-Jun N-terminal kinase/activator protein 1 axis is a novel molecular mechanism that accommodates hypoxia/reoxygenation-induced oxidative stress and apoptosis and provides a new direction for the study and treatment of hypoxia/reoxygenation.

MicroRNA-302d promotes the proliferation of human pluripotent stem cell-derived cardiomyocytes by inhibiting LATS2 in the Hippo pathway

Recent evidence has shown that cardiomyocytes (CMs) can proliferate at a low level after myocardial infarction (MI), but it is insufficient to reestablish heart function. Several microRNAs (miRNAs) have been proven to sufficiently induce rodent CM proliferation. However, whether miRNAs identified in rodents can promote human CM proliferation is unknown due to the poorly conserved functions of miRNAs among species. In the present study, we demonstrate that i) expression of microRNA-302d (miR-302d) decreased significantly during CM differentiation from human pluripotent stem cells (hPSCs) from day 4 to day 18; ii) miR-302d efficiently promoted proliferation of hPSC-derived CMs; iii) miR-302d promoted CM proliferation by targeting LATS2 in the Hippo pathway; and iv) RNA-sequencing analysis revealed that overexpression of miR-302d induced changes in gene expression, which mainly converged on the cell cycle. Our study provides further evidence for the therapeutic potential of miR-302d.

Effects of long non-coding RNA uc.245 on cardiomyocyte-like differentiation in P19 cells via FOG2

Each year, cardiac diseases may cause a high morbidity and mortality worldwide. Long non-coding RNAs (lncRNAs) that contained ultra-conserved elements (UCEs) may play important roles on cardiomyocytes differentiation. Further investigations underlying mechanisms of lncRNA-UC regulating embryonic heart development are necessary. In this study, we investigated the effects of lnc-uc.245 on proliferation, migration, apoptosis, and cardiomyocyte-like differentiation in P19 cells with DMSO stimulation, and hypothesized that lnc-uc.245 would influence cardiomyocytes differentiation via FOG2. Lentiviral vectors of pGPU6/GFP/Neo-uc.245 and pGPU6/GFP/Neo-shRNA-uc.245 were respectively transfected into P19 cells to overexpress or silence uc.245. MTT assay, Annexin V-FITC/PI double-staining, scratch test and transwell assay were performed and the results showed that uc.245 overexpression could significantly suppress P19 cell proliferation, migration, cardiomyocyte-like differentiation but promote cell apoptosis. Contrarily, sh-uc.245 treatment caused the opposite changes. Uc.245 overexpression obviously downregulated the expression of cardiomyogenic-specific molecular markers (cTnI, ANP, α-MHC, Nkx2.5, GATA4, MEF2C) but remarkably upregulated the expression of FOG2. Subsequently, we transfected the recombinant vectors loaded FOG2 or shRRNA-FOG2 into P19 cells to further address the functional significance of FOG2 in uc.245-regulated cardiomyocyte-like differentiation. Interestingly, we found that overexpressing of FOG2 promoted cell proliferation, migration, and inhibited apoptosis both in uc.245 overexpressed and silenced P19 cells, especially in uc.245 silenced cell line. In addition, sh-FOG2 promoted cardiomyocyte-like differentiation and upregulated the expression of cardiomyogenic-specific markers at the gene and protein levels both in uc.245 overexpressed and silenced P19 cells. Similarly, this upregulation effect of sh-FOG2 was more obvious after uc.245 silencing. These findings suggest that FOG2 is a key mediator during uc.245-regulated differentiation of P19 cells into cardiomyocytes. It is expected that lnc-uc.245/FOG2 will become a promising therapeutic target for cardiac diseases.