The potential role and mechanism of circRNAs in foam cell formation

Semen Ziziphi Spinosae alleviates cardiomyocyte apoptosis in rats with coronary heart disease via the AMPK/SIRT1/PGC-1α signaling pathway activation

BACKGROUND

Coronary heart disease (CHD) represents a significant cardiovascular condition, with its occurrence increasing as a result of alterations in lifestyle and dietary habits. Semen Ziziphi Spinosae (SZS) is commonly utilized for the management of disorders associated with the nervous system, including conditions like depression and insomnia. Recent research has revealed its potential therapeutic properties for cardiovascular issues. Nevertheless, there exists a limited amount of research addressing the mechanisms involved.

PURPOSE

This research seeks to explore the protective effects that SZS has on cardiac tissue, specifically within the framework of CHD. By conducting this investigation, the study aims to uncover the various mechanisms that play a role in these protective effects. This understanding could yield significant insights into how SZS may result in the preservation and enhancement of cardiac health in patients affected by CHD.

STUDY DESIGN

The study innovatively combines multiple advanced techniques. It first integrates UPLC-Q-TOF/MS analysis and network pharmacology to identify SZS components. In vitro experiments were conducted using H9c2 rat cardiomyocytes, and in vivo experiments used a CHD model in SD rats. Multiple assays were performed for multi - level and multi - dimensional validation.

METHODS

In the initial stage, the primary components of SZS and their possible mechanisms for combating CHD were examined through UPLC-Q-TOF/MS analysis in conjunction with network pharmacology approaches. For the in vitro investigation, an ischemia-hypoxia model was established utilizing H9c2 rat cardiomyocytes. The CCK-8 assay was used to assess myocardial injury markers. TUNEL staining and Western blot techniques were employed to confirm the impact of SZS treatment on apoptosis in H9c2 cells. The expression levels of proteins associated with the AMPK/SIRT1/PGC-1α signaling pathway were measured using RT-qPCR and Western blotting, and the results were validated with the AMPK inhibitor, compound C. In the in vivo segment, a model of coronary heart disease (CHD) in SD rats was established through the administration of a high-fat emulsion diet combined with pituitrin injections. Cardiac function in the rats was evaluated through electrocardiograms and echocardiograms. Pathological changes in the heart were observed utilizing TTC and H&E staining. Kits were implemented to measure the serum biochemical indicators in the rats.RT - qPCR and Western blotting were employed to measure the expression levels of proteins related to the AMPK/SIRT1/PGC - 1α signaling pathway.

RESULTS

The study identified 67 in vitro components, 27 blood - absorbed components, and 12 metabolic components of SZS. Network pharmacology analysis suggested the AMPK/SIRT1/PGC - 1α signaling pathway as a key mechanism. In vitro and in vivo experiments showed that SZS increased cell viability, reduced apoptosis, and activated the AMPK/SIRT1/PGC - 1α signaling pathway. Inhibiting AMPK abolished SZS's effects. SZS also improved cardiac function and reduced myocardial damage in rats with CHD.

CONCLUSION

This study for the first time highlights that Semen Ziziphi Spinosae plays a beneficial role in cardiovascular health by activating the AMPK/SIRT1/PGC-1α signaling pathway and reducing apoptosis in cardiomyocytes. These findings support its potential application in the treatment of CHD and other cardiac conditions.

Circular RNA transcriptome across various development periods of Paralichthys olivaceus reveal skeletal muscle-specific circchd6 regulating myogenesis

The Japanese flounder (Paralichthys olivaceus) is greatly influenced in terms of muscle quality and quantity by the development of skeletal muscle. While the mechanisms underlying skeletal muscle development are well-studied, the role of non-coding RNAs, particularly circRNAs, in the skeletal muscle development of Japanese flounder remains unclear. To investigate the expression patterns of circRNAs during different developmental stages (JP1: 7 days, JP2: 90 days, JP3: 24 months (female), JP4: 24 months (male)) in Japanese flounder, we performed transcriptome sequencing analysis. We identified a total of 3523 circRNAs, of which 10.19 % were differentially expressed. These differentially expressed (DE) circRNAs were studied, and their impacts on muscle development were analyzed. The RNA interaction network revealed that skeletal muscle-specific circchd6 targeted novel-miR-508 and further regulated dual specificity tyrosine-phosphorylation regulated kinase 2 (dyrk2). Functional analysis showed that overexpressed circchd6 and dyrk2 promoted myoblast proliferation and differentiation, while novel-miR-508 inhibited both. Our study identified the circchd6-novel-miR-508-dyrk2 axis as a regulatory mechanism and provided new evidence for the use of epigenetic approaches in genetic breeding.

Novel molecular mechanisms of immune evasion in hepatocellular carcinoma: NSUN2-mediated increase of SOAT2 RNA methylation

BACKGROUND

Hepatocellular carcinoma (HCC) is a deadly malignancy known for its ability to evade immune surveillance. NOP2/Sun RNA methyltransferase family member 2 (NSUN2), an RNA methyltransferase involved in carcinogenesis, has been associated with immune evasion and energy metabolism reprogramming. This study aimed to examine the molecular mechanisms underlying the involvement of NSUN2 in immune evasion and metabolic reprogramming of HCC.

METHODS

Single-cell transcriptomic sequencing was applied to examine cellular composition changes, particularly immune cell dynamics, in HCC and adjacent normal tissues. Bulk RNA-seq and proteomics identified key genes and proteins. Methylation sequencing and methylated RNA immunoprecipitation (MeRIP) were carried out to characterize the role of NSUN2 in 5-methylcytosine (m5C) modification of sterol O-acyltransferase 2 (SOAT2). Clinical samples from 30 HCC patients were analyzed using reverse transcription-quantitative polymerase chain reaction and Western blotting. Gene expression was manipulated using CRISPR/Cas9 and lentiviral vectors. In vitro co-culture models and metabolomics were used to study HCC cell-T cell interactions, energy metabolism, and immune evasion. Tumor growth in an orthotopic mouse model was monitored by bioluminescence imaging, with subsequent measurements of tumor weight, volume, and immunohistochemical staining.

RESULTS

Single-cell transcriptomic analysis identified a marked increase in malignant cells in HCC tissues. Cell communication analysis indicated that tumor cells might promote cancer progression by evading immune clearance. Multi-omics analyses identified NSUN2 as a key regulator in HCC development. MeRIP confirmed that NSUN2 facilitated the m5C modification of SOAT2. Analysis of human HCC tissue samples demonstrated pronounced upregulation of NSUN2 and SOAT2, along with elevated m5C levels in HCC tissues. In vitro experiments uncovered that NSUN2 augmented the reprogramming of energy metabolism and repressed the activity and cytotoxicity of CD8+ T cells, contributing to immune evasion. In vivo studies further substantiated the role of NSUN2 in fostering immune evasion and tumor formation of HCC by modulating the m5C modification of SOAT2.

CONCLUSIONS

The findings highlight the critical role of NSUN2 in driving HCC progression through the regulation of m5C modification on SOAT2. These findings present potential molecular markers for HCC diagnosis and therapeutic targets for its treatment.

Recent Advances in the Mutual Regulation of m6A Modification and Non-Coding RNAs in Atherosclerosis

Atherosclerosis, a progressive inflammatory disease of the arteries, remains a leading cause of cardiovascular morbidity and mortality worldwide. Recent years have witnessed the pivotal role of N6-methyladenosine (m6A) RNA methylation in regulating various biological processes, including those implicated in atherosclerosis. Current evidence suggested that m6A regulators (writers, erasers, and readers) participated in the modification of multiple non-coding RNAs (ncRNAs), including microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs), thereby affecting their metabolism and functions. Meanwhile, ncRNAs have also emerged as key modulator of m6A regulators expression in turn. Therefore, understanding the mutual regulation between m6A modifications and ncRNAs is of great significance to identify novel therapeutic targets for atherosclerosis and has great clinical application prospects. This review aims to summarize the recent advances in the reciprocal regulation and provide insights into the interaction between m6A modification and ncRNAs in the context of atherosclerosis.

Serum CircNIPSNAP3A is Associated with Metabolic Disorders, Atherosclerosis and Severity of Coronary Artery Disease in a Chinese Population

The relationships of serum circNIPSNAP3A and circHIPK3 with metabolic disorders, atherosclerosis and severity of coronary artery disease (CAD) remain to be clarified. Three hundred and thirty-eight subjects were categorized into normal coronary artery, atherosclerosis and CAD groups. Clinical data including anthropometric indexes, medical history, and physiological and biochemical parameters were collected. Serum circNIPSNAP3A and circHIPK3 were determined by quantitative real-time PCR. CAD severity was evaluated by clinical manifestation, electrocardiogram and coronary angiography. Both CAD and atherosclerosis groups had a higher serum level of circNIPSNAP3A than the normal coronary artery group (P < 0.05 for all). The subjects with a high percentage (> 66th percentile) of circNIPSNAP3A had higher mean levels of triglycerides, uric acid and homocysteine, and lower mean levels of high-density lipoprotein cholesterol and apolipoprotein AI than those with a low percentage (< 33rd percentile) of circNIPSNAP3A. Notably, circNIPSNAP3A is significantly and independently associated with CAD, and subjects with a high percentage of circNIPSNAP3A had more diseased coronary branches and a higher incidence of acute coronary syndrome than those with a low percentage of circNIPSNAP3A. Regarding circHIPK3, subjects with a medium or high percentage of circHIPK3 had a lower mean level of apolipoprotein AI than those with a low percentage of circHIPK3, but no significant differences in the incidence and severity of CAD among the < 33rd, 33rd-66th, and > 66th percentiles of circHIPK3 were detected. Serum circNIPSNAP3A is related to cardiovascular risk factors and CAD severity, and may be a potential prognostic marker and/or therapeutic target for CAD.

Is the suppression of CD36 a promising way for atherosclerosis therapy?

Atherosclerosis is the main underlying pathology of many cardiovascular diseases and is marked by plaque formation in the artery wall. It has posed a serious threat to the health of people all over the world. CD36 acts as a significant regulator of lipid homeostasis, which is closely associated with the onset and progression of atherosclerosis and may be a new therapeutic target. The abnormal overexpression of CD36 facilitates lipid accumulation, foam cell formation, inflammation, endothelial apoptosis, and thrombosis. Numerous natural products and lipid-lowering agents are found to target the suppression of CD36 or inhibit the upregulation of CD36 to prevent and treat atherosclerosis. Here, the structure, expression regulation and function of CD36 in atherosclerosis and its related pharmacological therapies are reviewed. This review highlights the importance of drugs targeting CD36 suppression in the treatment and prevention of atherosclerosis, in order to develop new therapeutic strategies and potential anti-atherosclerotic drugs both preclinically and clinically.

Circular RNAs Variously Participate in Coronary Atherogenesis

Over the past decade, numerous studies have shown that circular RNAs (circRNAs) play a significant role in coronary artery atherogenesis and other cardiovascular diseases. They belong to the class of non-coding RNAs and arise as a result of non-canonical splicing of premature RNA, which results in the formation of closed single-stranded circRNA molecules that lack 5'-end caps and 3'-end poly(A) tails. circRNAs have broad post-transcriptional regulatory activity. Acting as a sponge for miRNAs, circRNAs compete with mRNAs for binding to miRNAs, acting as competing endogenous RNAs. Numerous circRNAs are involved in the circRNA-miRNA-mRNA regulatory axes associated with the pathogenesis of cardiomyopathy, chronic heart failure, hypertension, atherosclerosis, and coronary artery disease. Recent studies have shown that сirc_0001445, circ_0000345, circ_0093887, сircSmoc1-2, and circ_0003423 are involved in the pathogenesis of coronary artery disease (CAD) with an atheroprotective effect, while circ_0002984, circ_0029589, circ_0124644, circ_0091822, and circ_0050486 possess a proatherogenic effect. With their high resistance to endonucleases, circRNAs are promising diagnostic biomarkers and therapeutic targets. This review aims to provide updated information on the involvement of atherogenesis-related circRNAs in the pathogenesis of CAD. We also discuss the main modern approaches to detecting and studying circRNA-miRNA-mRNA interactions, as well as the prospects for using circRNAs as biomarkers and therapeutic targets for the treatment of cardiovascular diseases.

Lipid-laden foam cells in the pathology of atherosclerosis: shedding light on new therapeutic targets

INTRODUCTION

Lipid-laden foam cells within atherosclerotic plaques are key players in all phases of lesion development including its progression, necrotic core formation, fibrous cap thinning, and eventually plaque rupture. Manipulating foam cell biology is thus an attractive therapeutic strategy at early, middle, and even late stages of atherosclerosis. Traditional therapies have focused on prevention, especially lowering plasma lipid levels. Despite these interventions, atherosclerosis remains a major cause of cardiovascular disease, responsible for the largest numbers of death worldwide.

AREAS COVERED

Foam cells within atherosclerotic plaques are comprised of macrophages, vascular smooth muscle cells, and other cell types which are exposed to high concentrations of lipoproteins accumulating within the subendothelial intimal layer. Macrophage-derived foam cells are particularly well studied and have provided important insights into lipid metabolism and atherogenesis. The contributions of foam cell-based processes are discussed with an emphasis on areas of therapeutic potential and directions for drug development.

EXERT OPINION

As key players in atherosclerosis, foam cells are attractive targets for developing more specific, targeted therapies aimed at resolving atherosclerotic plaques. Recent advances in our understanding of lipid handling within these cells provide insights into how they might be manipulated and clinically translated to better treat atherosclerosis.

The potential role and mechanism of circRNA/miRNA axis in cholesterol synthesis

Cholesterol levels are an initiating risk factor for atherosclerosis. Many genes play a central role in cholesterol synthesis, including HMGCR, SQLE, HMGCS1, FDFT1, LSS, MVK, PMK, MVD, FDPS, CYP51, TM7SF2, LBR, MSMO1, NSDHL, HSD17B7, DHCR24, EBP, SC5D, DHCR7, IDI1/2. Especially, HMGCR, SQLE, FDFT1, LSS, FDPS, CYP51, and EBP are promising therapeutic targets for drug development due to many drugs have been approved and entered into clinical research by targeting these genes. However, new targets and drugs still need to be discovered. Interestingly, many small nucleic acid drugs and vaccines were approved for the market, including Inclisiran, Patisiran, Inotersen, Givosiran, Lumasiran, Nusinersen, Volanesorsen, Eteplirsen, Golodirsen, Viltolarsen, Casimersen, Elasomeran, Tozinameran. However, these agents are all linear RNA agents. Circular RNAs (circRNAs) may have longer half-lives, higher stability, lower immunogenicity, lower production costs, and higher delivery efficiency than these agents due to their covalently closed structures. CircRNA agents are developed by several companies, including Orna Therapeutics, Laronde, and CirCode, Therorna. Many studies have shown that circRNAs regulate cholesterol synthesis by regulating HMGCR, SQLE, HMGCS1, ACS, YWHAG, PTEN, DHCR24, SREBP-2, and PMK expression. MiRNAs are essential for circRNA-mediated cholesterol biosynthesis. Notable, the phase II trial for inhibiting miR-122 with nucleic acid drugs has been completed. Suppressing HMGCR, SQLE, and miR-122 with circRNA_ABCA1, circ-PRKCH, circEZH2, circRNA-SCAP, and circFOXO3 are the promising therapeutic target for drug development, specifically the circFOXO3. This review focuses on the role and mechanism of the circRNA/miRNA axis in cholesterol synthesis in the hope of providing knowledge to identify new targets.