circ_TGFBR2 Inhibits Vascular Smooth Muscle Cells Phenotypic Switch and Suppresses Aortic Dissection Progression by Sponging miR-29a

Single-Cell RNA-Seq Reveals Injuries in Aortic Dissection and Identifies PDGF Signalling Pathway as a Potential Therapeutic Target

Aortic dissection (AD) represents a critical condition characterised by a tear in the inner lining of the aorta, leading to the leakage of blood into the layers of the aortic wall, posing a significant risk to life. However, the pathogenesis is unclear. In this study, scRNA-seq was applied to cells derived from aortas of both AD and non-AD donors (control) to unveil the cellular landscape. ScRNA-seq data uncover significant cellular heterogeneity in AD aortas. Specifically, we observed an accumulation of CD4+ T cells, which contributed to inflammation and cell death, and abnormal collagen formation mediated by fibroblast cells in AD. Moreover, we revealed a greater prevalence of cell death, oxidative stress and senescence in AD aorta cells. Furthermore, we found a decrease in the percentage of vascular stem cells (VSCs), along with a repression in their ability to differentiate into contractile vascular smooth muscle cells (VSMCs). Finally, our data demonstrated that the PDGF signalling pathway was activated in AD. We found that PDGF activation could lead to VSMCs aberrant switch from contractile to synthetic phenotype, which could be ameliorated by PDGF inhibitor. This underscores the potential of the PDGF as a therapeutic target for AD. In summary, our study highlights the cellular heterogeneity and associated injuries within aortas affected by AD, including cell death, oxidative stress, senescence and dysregulation of signalling pathways influencing the aberrant phenotypic switch of VSMCs. These insights offer valuable contributions to understanding the molecular mechanisms underlying AD and present new avenues for therapeutic intervention in this condition.

CircNRIP1 promotes proliferation, migration and phenotypic switch of Ang II-induced HA-VSMCs by increasing CXCL5 mRNA stability via recruiting IGF2BP1

Circular RNA (circRNA) has been found to be differentially expressed and involved in regulating the processes of human diseases, including thoracic aortic dissection (TAD). However, the role and mechanism of circNRIP1 in the TAD process are still unclear. GEO database was used to screen the differentially expressed circRNA and mRNA in type A TAD patients and age-matched normal donors. Angiotensin II (Ang II)-induced human aortic vascular smooth muscle cells (HA-VSMCs) were used to construct TAD cell models. The expression levels of circNRIP1, NRIP1, CXC-motif chemokine 5 (CXCL5) and IGF2BP1 were detected by quantitative real-time PCR. Cell proliferation and migration were determined by EdU assay, transwell assay and wound healing assay. The protein levels of synthetic phenotype markers, contractile phenotype markers, CXCL5 and IGF2BP1 were tested by western blot analysis. The interaction between IGF2BP1 and circNRIP1/CXCL5 was confirmed by RIP assay, and CXCL5 mRNA stability was assessed by actinomycin D assay. CircNRIP1 was upregulated in TAD patients and Ang II-induced HA-VSMCs. Knockdown of circNRIP1 suppressed Ang II-induced proliferation, migration and phenotypic switch of HA-VSMCs. Also, high expression of CXCL5 was observed in TAD patients, and its knockdown could inhibit Ang II-induced HA-VSMCs proliferation, migration and phenotypic switch. Moreover, CXCL5 overexpression reversed the regulation of circNRIP1 knockdown on Ang II-induced HA-VSMCs functions. Mechanistically, circNRIP1 could competitively bind to IGF2BP1 and subsequently enhance CXCL5 mRNA stability. CircNRIP1 might contribute to TAD progression by promoting CXCL5 mRNA stability via recruiting IGF2BP1.

A review of KLF4 and inflammatory disease: Current status and future perspective

Inflammation is the response of the human body to injury, infection, or other abnormal states, which is involved in the development of many diseases. As a member of the Krüppel-like transcription factors (KLFs) family, KLF4 plays a crucial regulatory role in physiological and pathological processes due to its unique dual domain of transcriptional activation and inhibition. A growing body of evidence has demonstrated that KLF4 plays a pivotal role in the pathogenesis of various inflammatory disorders, including inflammatory bowel disease, osteoarthritis, renal inflammation, pneumonia, neuroinflammation, and so on. Consequently, KLF4 has emerged as a promising new therapeutic target for inflammatory diseases. This review systematically generalizes the molecular regulatory network, specific functions, and mechanisms of KLF4 to elucidate its complex roles in inflammatory diseases. An in-depth study on the biological function of KLF4 is anticipated to offer a novel research perspective and potential intervention strategies for inflammatory diseases.

Circ_0000006 and circ_0000160 regulate hsa-let-7e-5p/UBQLN4 axis in aortic dissection progression

Aortic aneurysms (AA) and aorta dissection (AD) are life-threatening conditions with a rising incidence and high mortality rate. Recent research has linked non-coding RNAs to the regulation of AA and AD progression. In this study, we performed circRNA sequencing, microRNA (miRNA) sequencing, and messenger RNA (mRNA) sequencing on plasma samples from AA and AD patients to identify the key circRNA-miRNA-mRNA axis involved in the transition from AA to AD. Our results showed elevated levels of circ_0000006 and circ_0000160, along with decreased levels of hsa-let-7e-5p in AD samples compared to AA samples. Predictive analysis suggested that circ_0000006 and circ_0000160 potentially target hsa-let-7e-5p, which in turn may bind to the mRNA of Ubiquilin 4 (UBQLN4). In an AD cell model using vascular smooth muscle cells (VSMCs), silencing circ_0000006 and circ_0000160 attenuated the effects of platelet-derived growth factor (PDGF)-induced phenotypic changes, proliferation, and migration. This effect was partially reversed by inhibiting hsa-let-7e-5p. Furthermore, we found that overexpression of UBQLN4 counteracted the effects of hsa-let-7e-5p, suggesting UBQLN4 as a downstream mediator of hsa-let-7e-5p. In an animal model of AD, knockdown of circ_0000006 and circ_0000160 also showed protective effects against aortic septation. Overall, our findings indicate that the upregulation of circ_0000006 and circ_0000160 contributes to the progression from AA to AD by influencing abnormal phenotypic changes, migration, and proliferation of VSMCs. The Hsa-let-7e-5p/UBQLN4 axis may play a critical role in AD development. Targeting circ_0000006 and circ_0000160 could be a potential therapeutic strategy for preventing the progression of AD.

Downregulation of LILRB4 Promotes Human Aortic Smooth Muscle Cell Contractile Phenotypic Switch and Apoptosis in Aortic Dissection

Aortic dissection (AD) is a severe vascular disease with high rates of mortality and morbidity. However, the underlying molecular mechanisms of AD remain unclear. Differentially expressed genes (DEGs) were screened by bioinformatics methods. Alterations of histopathology and inflammatory factor levels in β-aminopropionitrile (BAPN)-induced AD mouse model were evaluated through Hematoxylin-Eosin (HE) staining and Enzyme-linked immunosorbent assay (ELISA), respectively. Reverse transcription quantitative real-time polymerase chain reaction was performed to detect DEGs expression. Furthermore, the role of LILRB4 in AD was investigated through Cell Counting Kit-8 (CCK-8), wound healing, and flow cytometry. Western blotting was employed to assess the phenotypic switch and extracellular matrix (ECM)-associated protein expressions in platelet-derived growth factor-BB (PDGF-BB)-stimulated in vitro model of AD. In the AD mouse model, distinct dissection formation was observed. TNF-α, IL-1β, IL-8, and IL-6 levels were higher in the AD mouse model than in the controls. Six hub genes were identified, including LILRB4, TIMP1, CCR5, CCL7, MSR1, and CLEC4D, all of which were highly expressed. Further exploration revealed that LILRB4 knockdown inhibited the cell vitality and migration of PDGF-BB-induced HASMCs while promoting apoptosis and G0/G1 phase ratio. More importantly, LILRB4 knockdown promoted the protein expression of α-SMA and SM22α, while decreasing the expression of Co1, MMP2, and CTGF, which suggested that LILRB4 silencing promoted contractile phenotypic transition and ECM stability. LILRB4 knockdown inhibits the progression of AD. Our study provides a new potential target for the clinical treatment of AD.

Comparative Analysis of Circular RNAs Expression and Function between Aortic and Intracranial Aneurysms

An aneurysm is an abnormal enlargement or bulging of the wall of a blood vessel. Most often, aneurysms occur in large blood vessels - the aorta (Thoracic Aortic Aneurysm (TAA) and Abdominal Aortic Aneurysm (AAA)) and brain vessels (Intracranial Aneurysm (IA)). Despite the presence of significant differences in the pathogenesis of the development and progression of IA and TAA/AAA, there are also similarities. For instance, both have been shown to be strongly influenced by shear stress, inflammatory processes, and enzymatic destruction of the elastic lamellae and extracellular matrix (ECM) proteins of the vascular wall. Moreover, although IA and TAA are predominantly considered arteriopathies with different pathological mechanisms, they share risk factors with AAA, such as hypertension and smoking. However, there is a need for a more in- -depth study of the key elements that may influence the formation and progression of a particular aneurysm to find ways of therapeutic intervention or search for a diagnostic tool. Today, it is known that the disruption of gene expression is one of the main mechanisms that contribute to the development of aneurysms. At the same time, growing evidence suggests that aberrant epigenetic regulation of gene function is strongly related to the genesis of aneurysms. Although much has been studied of the known protein-coding genes, circular RNAs (circRNAs), a relatively new and rapidly evolving large family of transcripts, have recently received much scientific attention. CircRNAs regulate gene expression through the sponging of microRNAs (miRNAs) and can also be used as therapeutic targets and biomarkers. Increasing evidence has implicated circRNAs in the pathogenesis of multiple cardiovascular diseases, including the development of aneurysms. However, the mechanism of dysregulation of certain circRNAs in a particular aneurysm remains to be studied. The discovery of circRNAs has recently advanced our understanding of the latest mode of miRNAs/target genes regulation in the development and progression of IA and TAA/AAA. The aim of this study is to compare the expression profiles of circRNAs to search for similar or different effects of certain circRNAs on the formation and progression of IA and TAA/AAA.

Epigenomics in aortic dissection: From mechanism to therapeutics

Aortic dissection (AD) has an unfavorable prognosis. It requires early diagnosis, appropriate treatment strategies, and suspicion to recognize symptoms; thus, it is commonly described as an acute aortic emergency. The clinical manifestations of painless AD are complex and variable. However, there is no effective treatment to prevent the progression of AD. Therefore, study of the molecular targets and mechanisms of AD to enable prevention or early intervention is particularly important. Although multiple gene mutations have been proposed as linked to AD development, evidence that multiple epigenetic elements are strongly associated is steadily increasing. These epigenetic processes include DNA methylation, N6-methyladenosine, histone modification, non-histone posttranslational modification, and non-coding RNAs (ncRNAs). Among these processes, resveratrol targeting Sirtuin 1 (SIRT1), 5-azacytidine (5azaC) targeting DNA methyltransferase (DNMT), and vitamin C targeting ten-eleven translocation 2 (Tet2) showed unique advantages in improving AD and vascular dysfunction. Finally, we explored potential epigenetic drugs and diagnostic methods for AD, which might provide options for the future.

Exosomal circ-1199 derived from EPCs exposed to oscillating shear stress acts as a sponge of let-7g-5p to promote endothelial-mesenchymal transition of EPCs by increasing HMGA2 expression

AIMS

Our previous study showed that oscillatory shear stress (OSS) induces endothelial progenitor cells (EPCs) to undergo endothelial to mesenchymal transition (EndoMT), which may contribute to the onset and progression of atherosclerosis (AS). However, the underlying mechanisms have not been elucidated. A recent study showed that exosomes (Exos) released from EPCs played a key role in various cardiovascular diseases. The purpose of this study was to identify the role and mechanism of Exos released by EPCs exposed to OSS in EPC EndoMT.

MAIN METHODS

EPCs derived from the human umbilical cord blood were cultured and characterized. The Flexcell flow STR-4000 parallel plate flow chamber system was employed to apply OSS (±3.5 dyne/cm², 1 Hz) to EPCs for 12 h. Then, Exos were extracted from the cellular supernatant (Static-Exos) or perfusate (OSS-Exos) by exoEasy Maxi Kit. Afterward, cellular intervention, angiogenesis assays, high-throughput sequencing and online database predictions were used to identify the role and mechanism of OSS-Exos in EPC EndoMT.

KEY FINDINGS

OSS-Exos inhibited angiogenesis, promoted the proliferation of EPCs both in vivo and in vitro, and induced EPC EndoMT. In addition, the expression of circ-1199 in OSS-Exos was higher than that in Static-Exos. Moreover, circ-1199 induced EPC EndoMT. The dual-luciferase reporter gene assay showed that let-7g-5p was the direct target of circ-1199. Furthermore, OSS-Exos upregulated the expression of circ-1199 and then downregulated let-7g-5p, upregulating HMGA2, which activated p-Smad3/Smad3 and Snail.

SIGNIFICANCE

OSS-Exos played an important role in the EndoMT of EPCs, which was mediated by the circ-1199/let-7g-5p/HMGA2 signaling pathway. These studies would have a high probability of revealing the mechanism of EPC EndoMT.

Noncoding RNA in the Regulation of Acute Aortic Dissection: From Profile to Mechanism

Aortic dissection is a life-threatening condition caused by a tear in the intimal layer of the aorta or bleeding within the aortic wall, resulting in the separation of the layers of the aortic wall. As Nienaber reported, aortic dissection is most common in people 65-75 years old and has an incidence of 35 cases per 100,000 people per year in this population. Many pathogenic factors are involved in aortic dissection, including hypertension, dyslipidemia, and abnormality of the aortic intima caused by genetic variation. However, with the development of gene sequencing and transgenic technology, genetic methods are being used for the diagnosis and treatment of diseases, including acute aortic dissection. Genetic research on acute aortic dissection began around 2006. Recently, research on acute aortic dissection has mainly focused on microRNA (miRNA). Studies have found that miRNA plays a critical regulatory role in the occurrence and development of acute aortic dissection. By regulating miRNA expression, acute aortic dissection can be prevented and treated.

Emerging Role of Non-Coding RNAs in Aortic Dissection

Aortic dissection (AD) is a fatal cardiovascular acute disease with high incidence and mortality, and it seriously threatens patients’ lives and health. The pathogenesis of AD mainly includes vascular inflammation, extracellular matrix degradation, and phenotypic conversion as well as apoptosis of vascular smooth muscle cells (VSMCs); however, its detailed mechanisms are still not fully elucidated. Non-coding RNAs (ncRNAs), including microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs), are an emerging class of RNA molecules without protein-coding ability, and they play crucial roles in the progression of many diseases, including AD. A growing number of studies have shown that the dysregulation of ncRNAs contributes to the occurrence and development of AD by modulating the expression of specific target genes or the activity of related proteins. In addition, some ncRNAs exhibit great potential as promising biomarkers and therapeutic targets in AD treatment. In this review, we systematically summarize the recent findings on the underlying mechanism of ncRNA involved in AD regulation and highlight their clinical application as biomarkers and therapeutic targets in AD treatment. The information reviewed here will be of great benefit to the development of ncRNA-based therapeutic strategies for AD patients.

Non-coding RNAs Regulate the Pathogenesis of Aortic Dissection

Aortic dissection (AD) is a fatal cardiovascular disease. It is caused by a rupture of the aortic intima or bleeding of the aortic wall that leads to the separation of different aortic wall layers. Patients with untreated AD have a mortality rate of 1–2% per hour after symptom onset. Therefore, effective biomarkers and therapeutic targets are needed to reduce AD-associated mortality. With the development of molecular technology, researchers have begun to explore the pathogenesis of AD at gene and protein levels, and have made some progress, but the pathogenesis of AD remains unclear. Non-coding RNAs, such as microRNAs, lncRNAs, and circRNAs, have been identified as basic regulators of gene expression and are found to play a key role in the pathogenesis of AD. Thus, providing a theoretical basis for developing these non-coding RNAs as clinical biomarkers and new therapeutic targets for AD in the future. Previous studies on the pathogenesis of AD focused on miRNAs, but recently, there have been an increasing number of studies that explore the role of lncRNAs, and circRNAs in AD. This review summarizes the existing knowledge on the roles of various non-coding RNAs in the pathogenesis of AD, discusses their potential role as clinical biomarkers and therapeutic targets, states the limitations of existing evidence, and recommends future avenues of research on the pathogenesis of AD.