Small Molecules with Big Impacts on Cardiovascular Diseases

Metagenomic sequencing revealed the regulative effect of Danshen and Honghua herb pair on the gut microbiota in rats with myocardial ischemia injury

In recent years, more and more evidence has shown that the disorder of gut microbiota (GM) is closely correlated with myocardial ischemia (MI). Even though the Danshen and Honghua herb pair (DHHP) is widely used in treating cardiovascular disease in China and exhibits obvious clinical efficacy on MI, the anti-MI mechanism of DHHP remains and needs to be explored in depth. Thus, in this study, we investigated whether the amelioration effect and molecular mechanism of DHHP on MI were related to regulating GM through pharmacodynamics evaluation and metagenomic sequencing. Histopathological testing results showed that DHHP treatment could alleviate the pathological changes of myocardial tissue in the acute MI (AMI) rats induced by isoproterenol (ISO), especially structural disorder, irregular distribution, and enlargement of the myocardial space. These pathological changes were all alleviated to some extent by DHHP treatment. Biochemical analysis results suggested that compared with the control group, the serum levels of AST, CTn-I, CK-MB, and TNF-α in model group rats were notably decreased, and the CAT and SOD levels in serum were markedly increased. These abnormal trends were significantly reversed by DHHP treatment. Furthermore, metagenomic sequencing analysis results indicated that DHHP could improve disorders in the composition and function of GM in AMI rats, mainly reflected in increasing diversity and richness, and obviously enhancing the abundance of Bacteroides fluxus, B. uniformis, B. stercoris, Roseburia hominis, Schaedlerella arabinosiphila, and R. intestinalis, and reducing the abundance of Enterococcus avium and E. canintestini, which were associated with purine metabolism, tyrosine metabolism, cyanoamino acid metabolism, and glutathione metabolism. In conclusion, DHHP may attenuate ISO-induced MI by regulating the structure, composition, and function of GM, thus contributing to further our understanding of the anti-MI mechanisms of DHHP and providing new therapeutic ideas and diagnostic targets for the clinical studies of MI.

Significance of microRNA-targeted ErbB signaling pathway genes in cardiomyocyte differentiation

OBJECTIVE(S)

Cardiomyocyte differentiation is a complex process that follows the progression of gene expression alterations. The ErbB signaling pathway is necessary for various stages of cardiac development. We aimed to identify potential microRNAs targeting the ErbB signaling pathway genes by in silico approaches.

METHODS

Small RNA-sequencing data were obtained from GSE108021 for cardiomyocyte differentiation. Differentially expressed miRNAs were acquired via the DESeq2 package. Signaling pathways and gene ontology processes for the identified miRNAs were determined and the targeted genes of those miRNAs affecting the ErbB signaling pathway were determined.

RESULTS

Results revealed highly differentially expressed miRNAs were common between the differentiation stages and they targeted the genes involved in the ErbB signaling pathway as follows: let-7g-5p targets both CDKN1A and NRAS, while let-7c-5p and let-7d-5p hit CDKN1A and NRAS exclusively. let-7 family members targeted MAPK8 and ABL2. GSK3B was targeted by miR-199a-5p and miR-214-3p, and ERBB4 was targeted by miR-199b-3p and miR-653-5p. miR-214-3p, miR-199b-3p, miR-1277-5p, miR-21-5p, and miR-21-3p targeted CBL, mTOR, Jun, JNKK, and GRB1, respectively. MAPK8 was targeted by miR-214-3p, and ABL2 was targeted by miR-125b-5p and miR-1277-5p, too.

CONCLUSION

We determined miRNAs and their target genes in the ErbB signaling pathway in cardiomyocyte development and consequently heart pathophysiology progression.

First Discovery of Cholesterol-Lowering Activity of Parthenolide as NPC1L1 Inhibitor

Elevated cholesterol significantly increases the risk of developing atherosclerosis and coronary heart disease. The key to treating hypercholesterolemia is lowering plasma cholesterol levels. There have been no studies on the cholesterol-lowering potential of parthenolide (PTL), a naturally occurring small molecule from Tanacetum parthenium. Here, we first put forth PTL’s cholesterol-lowering ability to inhibit cellular uptake of cholesterol in a dose-dependent manner. Its performance was on par with the positive control drug, ezetimibe. Niemann–Pick C1 Like-1 (NPC1L1) has been identified as a potential therapeutic target for hypercholesterolemia. The interaction of PTL with NPC1L1 could be explained by the results of molecular docking and filipin staining further reinforces this hypothesis. Furthermore, PTL reduced the expression of NPC1L1 in HepG2 cells in a concentration-dependent manner, which suggests that PTL functions as a potential NPC1L1 inhibitor with therapeutic potential for hypercholesterolemia.

Circular RNAs: New Players in Cardiomyopathy

Cardiomyopathies comprise a heterogeneous group of cardiac diseases identified by myocardium disorders and diminished cardiac function. They often lead to heart failure or heart transplantation and constitute one of the principal causes of morbidity and mortality worldwide. Circular RNAs (circRNAs) are a novel type of noncoding RNAs. They are covalently closed and single-stranded and derived from the exons and introns of genes by alternative splicing. This specific structure renders them resistant to exonuclease digestion. Many recent studies have demonstrated that circRNAs are highly abundant and conserved and can play central roles in biological functions such as microRNA (miRNA) sponging, splicing, and transcription regulation. Emerging evidence indicates that circRNAs can play significant roles in cardiovascular diseases, including cardiomyopathies. In this review, we briefly describe the current understanding regarding the classification, nomenclature, characteristics, and function of circRNAs and report recent significant findings concerning the roles of circRNAs in cardiomyopathies. Furthermore, we discuss the clinical application potential of circRNAs as the therapeutic targets and diagnostic biomarkers of cardiomyopathies.

Tenascin-C as a noninvasive biomarker of coronary artery disease

BACKGROUND

Coronary artery disease (CAD), is the leading cause of mortality and morbidity worldwide. Tenascin-C (TNC) with high expression levels in inflammatory and cardiovascular diseases, leads to the rupture of atherosclerotic plaques. The origin of plaque destabilization can be associated to endothelial dysfunction. Given the high prevalence of CAD, finding valuable biomarkers for its early detection is of great interest. Using serum samples from patients with CAD and individuals without CAD, we assessed the efficacy of TNC expression levels in serum exosomes and during endothelial cell differentiation as a noninvasive biomarker of CAD.

METHODS

TNC expression was analyzed using the RNA-sequencing data sets of 6 CAD and 6 normal samples of blood exosomes and endothelial differentiation transitions. Additionally, TNC expression was investigated in the serum samples of patients with CAD and individuals without CAD via qRT-PCR. ROC curve analysis was employed to test the suitability of TNC expression alterations as a CAD biomarker.

RESULTS

TNC exhibited higher expression in the exosomes of the CAD samples than in those of the non-CAD samples. During endothelial differentiation, TNC expression was upregulated and then consistently downregulated in mature endothelial cells. Moreover, TNC was significantly upregulated in the serum of the CAD group (P = 0.02), with an AUC of 0.744 for the expression level (95% confidence interval, 0.582 to 0.907; P = 0.011). Hence its expression level can be discriminated CAD from non-CAD samples.

DISCUSSION

Our study is the first to confirm that altered TNC expression is associated with pathological CAD conditions in Iranian patients. The expression of TNC is involved in endothelial differentiation and CAD development. Accordingly, TNC can serve as a valuable noninvasive biomarker with potential application in CAD diagnosis.

Post-Transcriptional Effects of miRNAs on PCSK7 Expression and Function: miR-125a-5p, miR-143-3p, and miR-409-3p as Negative Regulators

The regulatory mechanism of PCSK7 gene is still unknown, although its encoded protein PC7 is the most ancient and highly conserved of all proprotein convertases and exhibits enzymatic and non-enzymatic functions in liver triglyceride regulation. Bioinformatics algorithms were used to predict regulatory microRNAs (miRNAs) of PCSK7 expression. This led to the identification of four miRNAs, namely miR-125a-5p, miR-143-3p, miR-409-3p, and miR-320a-3p, with potential binding sites on the 3′-untranslated region (3′-UTR) of human PCSK7 mRNA. The expression patterns of these miRNAs and PCSK7 mRNA were assessed in three different cell lines with quantitative polymerase chain reaction (qPCR), which revealed reciprocal expression patterns between the expression levels of the four selected miRNAs and PCSK7. Next, the interactions and effects of these miRNAs on PCSK7 expression levels were investigated via cell-based expression analysis, dual-luciferase assay, and Western blot analysis. The data revealed that PCSK7 mRNA levels decreased in cells transfected with vectors overexpressing miR-125a-5p, miR-143-3p, and miR-409-3p, but not miR-320a-3p. The dual-luciferase assay demonstrated that the above three miRNAs could directly interact with putative target sites in PCSK7 3′-UTR and regulate its expression, whereas miR-320-3p exhibited no interaction. Western blot analysis further revealed that the overexpression of miR-125a-5p in Huh7 cells inhibits the expression and ability of PC7 to cleave human transferrin receptor 1. Our results support a regulatory role of these miRNAs on PCSK7 expression and function and open the way to assess their roles in the regulation of PC7 activity in vivo in the development of hepatic steatosis.

EpisomiR, a New Family of miRNAs, and Its Possible Roles in Human Diseases

MicroRNAs (miRNAs) are synthesized through a canonical pathway and play a role in human diseases, such as cancers and cardiovascular, neurodegenerative, psychiatric, and chronic inflammatory diseases. The development of sequencing technologies has enabled the identification of variations in noncoding miRNAs. These miRNA variants, called isomiRs, are generated through a non-canonical pathway, by several enzymes that alter the length and sequence of miRNAs. The isomiR family is, now, expanding further to include episomiRs, which are miRNAs with different modifications. Since recent findings have shown that isomiRs reflect the cell-specific biological function of miRNAs, knowledge about episomiRs and isomiRs can, possibly, contribute to the optimization of diagnosis and therapeutic technology for precision medicine.

Linc-ROR has a Potential ceRNA Activity for OCT4A by Sequestering miR-335-5p in the HEK293T Cell Line

Linc-ROR has a regulatory role in reprogramming, and the core stem cell transcription factors, OCT4, SOX2, and NANOG, regulate its expression. MicroRNAs (miRNAs) are also a critical constituent of pivotal posttranscriptional regulatory pathways. One of such interactions is a competing endogenous RNA interaction that connects small and long non-coding RNAs with coding transcripts. Here, we aimed to investigate the existence of such associations between OCT4A, Linc-ROR, hsa-miR-335-5p, and hsa-miR-544. Bioinformatic analysis was performed to evaluate the expression status of OCT4A, Linc-ROR, miR-335, and miR-544 throughout differentiation as well as in various differentiated cells. The complete lengths of OCT4A and Linc-ROR, and OCT4A 3'-UTR were cloned in the luciferase reporter vector, and the precursors of miR-335 and miR-544 were cloned in expression vectors. Following the overexpression of miR-335 and miR-544 in the 5637 cell line, the endogenous expression of OCT4A and Linc-ROR was evaluated. Afterward, the expression vectors of miRNAs and the reporter vectors of OCT4A/Linc-ROR were co-transfected in the HEK293T cell line. Via the Dual-Luciferase assay, the effect of the overexpression of miRNAs on their two possible targets (Linc-ROR and OCT4A) was investigated. The bioinformatic analysis demonstrated a relatively similar expression pattern for OCT4A and Linc-ROR, while miR-335 showed a different expression status. Both miR-335 and miR-544 inhibited the endogenous expression of OCT4A. The Dual-Luciferase assay likewise confirmed the inhibitory effect of miR-335 and miR-544 on OCT4A expression. In contrast, the miR-335 inhibitory effect was reversed in the presence of Linc-ROR, resulting in the upregulation of OCT4A. Such evidence suggests that Linc-ROR may compete with OCT4A to interact with miR-335.

Targeting of Potassium Channels in Cardiac Arrhythmias

Cardiomyocytes are endowed with a complex repertoire of ion channels, responsible for the generation of action potentials (APs), travelling waves of electrical excitation, propagating throughout the heart and leading to cardiac contractions. Cardiac AP waveforms are shaped by a striking diversity of K⁺ channels. The pivotal role of K⁺ channels in cardiac health and disease is underscored by the dramatic impact that K⁺ channel dysfunction has on cardiac arrhythmias. The development of drugs targeted to specific K⁺ channels is expected to provide an optimized approach to antiarrhythmic therapy. Here, we review the functional roles of cardiac potassium channels under normal and diseased states. We survey current antiarrhythmic drugs (AADs) targeted to voltage-gated and Ca²⁺-activated K⁺ channels and highlight future research opportunities.

Mutational Spectrum of LDLR and PCSK9 Genes Identified in Iranian Patients With Premature Coronary Artery Disease and Familial Hypercholesterolemia

Familial hypercholesterolemia (FH) is a common, yet underdiagnosed, genetic disorder characterized by lifelong elevated low-density lipoprotein cholesterol levels, which can increase the risk of early-onset coronary artery disease (CAD). In the present study, we screened the nucleotide variations of the LDLR and PCSK9 genes, as well as a part of the APOB gene, in Iranian patients with FH and premature CAD to find the genetic cause of the disorder. Fifteen unrelated individuals with a clinical diagnosis of FH and premature CAD were recruited. Direct DNA sequencing was applied to screen the whole coding exons and exon-intron boundaries of the LDLR and PCSK9 genes and the main parts of their introns, together with exon 26 of the APOB gene. The pathogenicity of the identified mutations was investigated via either segregation analyses in the family or in silico predictive software. Six different point mutations (p.Cys148Tyr, p.Cys216Tyr, p.Cys302Trp, p.Cys338Trp, p.Leu479Gln, and p.G593Afs∗72) in LDLR and a double mutation (p.Asp172His and p.Ala53Val) in both LDLR and PCSK9 genes were identified in seven families with clinically diagnosed FH (43%), whereas no pathogenic mutations were found in eight families with clinically diagnosed FH. This study is the first to identify 1 pathogenic mutation in the LDLR gene (c.1014C > G [p.Cys338Trp]) and to cosegregate it from the affected individual in the family. No mutations were found in the APOB gene, whereas several silent mutations/polymorphisms were identified in the LDLR and PCSK9 genes. Genetic testing and reports on nucleotide alterations in the Iranian population are still limited. Our findings not only further confirm the significant role of FH in the incidence of premature CAD but also enlarge the spectrum of LDLR and PCSK9 variations and exhibit the heterogeneity of FH in Iranians. In patients with no mutation in the examined genes, the disease could be begotten either by a polygenic cause or by gene defects occurring in other related genes and regions not targeted in this study.

MiR-223-3p in Cardiovascular Diseases: A Biomarker and Potential Therapeutic Target

Cardiovascular diseases, involving vasculopathy, cardiac dysfunction, or circulatory disturbance, have become the major cause of death globally and brought heavy social burdens. The complexity and diversity of the pathogenic factors add difficulties to diagnosis and treatment, as well as lead to poor prognosis of these diseases. MicroRNAs are short non-coding RNAs to modulate gene expression through directly binding to the 3′-untranslated regions of mRNAs of target genes and thereby to downregulate the protein levels post-transcriptionally. The multiple regulatory effects of microRNAs have been investigated extensively in cardiovascular diseases. MiR-223-3p, expressed in multiple cells such as macrophages, platelets, hepatocytes, and cardiomyocytes to modulate their cellular activities through targeting a variety of genes, is involved in the pathological progression of many cardiovascular diseases. It participates in regulation of several crucial signaling pathways such as phosphatidylinositol 3-kinase/protein kinase B, insulin-like growth factor 1, nuclear factor kappa B, mitogen-activated protein kinase, NOD-like receptor family pyrin domain containing 3 inflammasome, and ribosomal protein S6 kinase B1/hypoxia inducible factor 1 α pathways to affect cell proliferation, migration, apoptosis, hypertrophy, and polarization, as well as electrophysiology, resulting in dysfunction of cardiovascular system. Here, in this review, we will discuss the role of miR-223-3p in cardiovascular diseases, involving its verified targets, influenced signaling pathways, and regulation of cell function. In addition, the potential of miR-223-3p as therapeutic target and biomarker for diagnosis and prediction of cardiovascular diseases will be further discussed, providing clues for clinicians.