TGF-β signaling and microRNA cross-talk regulates abdominal aortic aneurysm progression

MicroRNA Inhibiting Atheroprotective Proteins in Patients with Unstable Angina Comparing to Chronic Coronary Syndrome

Patients with unstable angina present clinical characteristics of atherosclerotic plaque vulnerability, contrary to chronic coronary syndrome patients. The process of athersclerotic plaque destabilization is also regulated by microRNA particles. In this study, the investigation on expression levels of microRNAs inhibiting the expression of proteins that protect from atherosclerotic plaque progression (miR-92a inhibiting KLF2, miR-10b inhibiting KLF4, miR-126 inhibiting MerTK, miR-98 inhibiting IL-10, miR-29b inhibiting TGFβ1) was undertaken. A number of 62 individuals were enrolled-unstable angina (UA, n = 14), chronic coronary syndrome (CCS, n = 38), and healthy volunteers (HV, n = 10). Plasma samples were taken, and microRNAs expression levels were assessed by qRT-PCR. As a result, the UA patients presented significantly increased miR-10b levels compared to CCS patients (0.097 vs. 0.058, p = 0.033). Moreover, in additional analysis when UA patients were grouped together with stable patients with significant plaque in left main or proximal left anterior descending ("UA and LM/proxLAD" group, n = 29 patients) and compared to CCS patients with atherosclerotic lesions in other regions of coronary circulation ("CCS other" group, n = 25 patients) the expression levels of both miR-10b (0.104 vs. 0.046; p = 0.0032) and miR-92a (92.64 vs. 54.74; p = 0.0129) were significantly elevated. In conclusion, the study revealed significantly increased expression levels of miR-10b and miR-92a, a regulator of endothelial protective KLF factors (KLF4 and KLF2, respectively) in patients with more vulnerable plaque phenotypes.

Therapeutic potential of natural products and underlying targets for the treatment of aortic aneurysm

Aortic aneurysm is a vascular disease characterized by irreversible vasodilatation that can lead to dissection and rupture of the aortic aneurysm, a life-threatening condition. Thoracic aortic aneurysm (TAA) and abdominal aortic aneurysm (AAA) are two main types. The typical treatments for aortic aneurysms are open surgery and endovascular aortic repair, which are only indicated for more severe patients. Most patients with aneurysms have an insidious onset and slow progression, and there are no effective drugs to treat this stage. The inability of current animal models to perfectly simulate all the pathophysiological states of human aneurysms may be the key to this issue. Therefore, elucidating the molecular mechanisms of this disease, finding new therapeutic targets, and developing effective drugs to inhibit the development of aneurysms are the main issues of current research. Natural products have been applied for thousands of years to treat cardiovascular disease (CVD) in China and other Asian countries. In recent years, natural products have combined multi-omics, computational biology, and integrated pharmacology to accurately analyze drug components and targets. Therefore, the multi-component and multi-target complexity of natural products have made them a potentially ideal treatment for multifactorial diseases such as aortic aneurysms. Natural products have regained popularity worldwide. This review provides an overview of the known natural products for the treatment of TAA and AAA and searches for potential cardiovascular-targeted natural products that may treat TAA and AAA based on various cellular molecular mechanisms associated with aneurysm development.

Roles and Mechanisms of miRNAs in Abdominal Aortic Aneurysm: Signaling Pathways and Clinical Insights

PURPOSE OF REVIEW

Abdominal aortic aneurysm refers to a serious medical condition that can cause the irreversible expansion of the abdominal aorta, which can lead to ruptures that are associated with up to 80% mortality. Currently, surgical and interventional procedures are the only treatment options available for treating abdominal aortic aneurysm patients. In this review, we focus on the upstream and downstream molecules of the microRNA-related signaling pathways and discuss the roles, mechanisms, and targets of microRNAs in abdominal aortic aneurysm modulation to provide novel insights for precise and targeted drug therapy for the vast number of abdominal aortic aneurysm patients.

RECENT FINDINGS

Recent studies have highlighted that microRNAs, which are emerging as novel regulators of gene expression, are involved in the biological activities of regulating abdominal aortic aneurysms. Accumulating studies suggested that microRNAs modulate abdominal aortic aneurysm development through various signaling pathways that are yet to be comprehensively summarized. A total of six signaling pathways (NF-κB signaling pathway, PI3K/AKT signaling pathway, MAPK signaling pathway, TGF-β signaling pathway, Wnt signaling pathway, and P53/P21 signaling pathway), and a total of 19 miRNAs are intimately associated with the biological properties of abdominal aortic aneurysm through targeting various essential molecules. MicroRNAs modulate the formation, progression, and rupture of abdominal aortic aneurysm by regulating smooth muscle cell proliferation and phenotype change, vascular inflammation and endothelium function, and extracellular matrix remodeling. Because of the broad crosstalk among signaling pathways, a comprehensive analysis of miRNA-mediated signaling pathways is necessary to construct a well-rounded upstream and downstream regulatory network for future basic and clinical research of AAA therapy.

Epigenetic modifications in abdominal aortic aneurysms: from basic to clinical

Abdominal Aortic Aneurysm (AAA) is a disease characterized by localized dilation of the abdominal aorta, involving multiple factors in its occurrence and development, ultimately leading to vessel rupture and severe bleeding. AAA has a high mortality rate, and there is a lack of targeted therapeutic drugs. Epigenetic regulation plays a crucial role in AAA, and the treatment of AAA in the epigenetic field may involve a series of related genes and pathways. Abnormal expression of these genes may be a key factor in the occurrence of the disease and could potentially serve as promising therapeutic targets. Understanding the epigenetic regulation of AAA is of significant importance in revealing the mechanisms underlying the disease and identifying new therapeutic targets. This knowledge can contribute to offering AAA patients better clinical treatment options beyond surgery. This review systematically explores various aspects of epigenetic regulation in AAA, including DNA methylation, histone modification, non-coding RNA, and RNA modification. The analysis of the roles of these regulatory mechanisms, along with the identification of relevant genes and pathways associated with AAA, is discussed comprehensively. Additionally, a comprehensive discussion is provided on existing treatment strategies and prospects for epigenetics-based treatments, offering insights for future clinical interventions.

Clinical value of serum miR-1-3p as a potential circulating biomarker for abdominal aortic aneurysm

BACKGROUND

Although abdominal aortic aneurysm (AAA) is associated with life-threatening complications, there are still limited reliable biomarkers for diagnostic purpose. MicroRNAs (miRNAs) have been proposed as the potential diagnostic and risk stratification markers of AAA patients, and we aim to evaluate the serum level of miR-1-3p and its diagnostic value in AAA.

METHODS

This study included 200 AAA patients and 200 controls. Demographic data and clinical information were collected from the subjects' medical records. Individual image analyses of AAA morphology were determined based on computed tomography angiography (CTA). The levels of serum miRNA expression were detected by quantitative real-time PCR. Bioinformatics tools were used to identify the target genes of miR-1-3p and their potential biological functions were further enriched.

RESULTS

Serum miR-1-3p levels in the AAA group were significantly lower when compared with those in the control group in overall and subgroup comparisons. It was negatively related to WBC, CRP, maximal aneurysm diameter, area, and volume in AAA patients. Circulating miR-1-3p levels could significantly discriminate between AAA patients and healthy individuals with an area under the curve (AUC) of 0.672 (95% CI = 0.619-0.724, p < 0.001), a sensitivity of 84.5% and a specificity of 45.5%. Serum miR-1-3p was associated with a reduced risk of AAA even after adjustment for possible risk factors (OR = 0.440 per unit increase, 95% CI = 0.301-0.643, p < 0.001). And low levels of serum miR-1-3p could significantly elevate the risk of AAA in both univariate and multivariate logistic regression analyses with ORs of 4.076 and 4.136, respectively (all p < 0.001). Further GO enrichment analysis revealed that miR-1-3p was mainly involved in negative regulation of apoptotic process, sprouting angiogenesis, angiogenesis, positive regulation of blood vessel endothelial cell migration, positive regulation of cell proliferation, regulation of cell shape, etc.

CONCLUSIONS

MiR-1-3p can be used as a promising circulating biomarker in the development of AAA, and it may participate in multiple biological processes to play a crucial role in AAA pathogenesis.

Circulating miRNAs as biomarkers for diagnosis, surveillance and post-operative follow-up of abdominal aortic aneurysms

OBJECTIVE

To provide a summary of the current state of research in English medical literature on circulating miRNAs, as biomarkers for AAA. Additionally, for the most commonly mentioned circulating miRNAs in the literature, to attempt a documentation of the biological mechanisms underlying their role in AAA development.

METHODS

A literature search was undertaken in the MEDLINE database. Only reports that involved peripheral blood samples (whole blood, plasma, serum) were included. The following terms were used in combination: microrna, mirna, abdominal aortic aneurysm, human, circulating, plasma, serum, endovascular and EVAR.

RESULTS

A total of 25 reports, published from 2012 to 2022 were included with a total of 1259 patients with AAA, predominantly men (N= 1040, 90%). Six of these reports recruited healthy donors who underwent ultrasound screening for AAA as control samples. The majority of studies were undertaken in plasma samples and the most preferred microRNA profiling method was Real - Time quantitative polymerase chain reaction (qRT-PCR). The following nine miRNAs (out of a total of 76) were studied in more than two references: miR-145, miR-24, miR-33, miR-125, let-7, miR-15, miR-191, miR-29 and miR-133.

CONCLUSION

The nine miRNAs described in this study, are implicated in known pathogenetic mechanisms of AAA such as atherosclerosis, vascular smooth muscle cell phenotype switch and apoptosis, vascular inflammation, extracellular matrix degradation and lipid metabolism. Identifying disease-specific miRNAs, in combination with other clinical parameters, as indicators of AAA, is crucial for early diagnosis as well as follow-up of AAAs. For future research on miRNAs as AAA biomarkers, strict case and control group definitions, sample acquisition protocols, and miRNA expression profiling techniques are warranted.

Statin therapy protects against abdominal aortic aneurysms by inducing the accumulation of regulatory T cells in ApoE-/- mice

CD4⁺CD25⁺ regulatory T cells (Tregs) have been shown to protect against abdominal aortic aneurysm (AAA) progression. Statins have immunomodulatory properties, and their effect on AAA partly depends on immune-related mechanisms. In this study, we aimed to explore whether there is an association between statins and Tregs in AAA progression. Sixty ApoE^-/- mice were randomly divided into four groups (n = 15 per group): A, saline group; B, control group; C, simvastatin group (intragastric administration of simvastatin); and D, PC61 group (simvastatin combined with an intraperitoneal injection of 100 μg CD25-depleting antibody PC61). After 2 weeks of simvastatin treatment, the mice received a continuous subcutaneous infusion of angiotensin II (Ang II; B, C, and D groups) or saline (A group) for 28 days. Simvastatin therapy for 6 weeks significantly decreased the incidence and severity of AAA and inhibited the apoptosis of smooth muscle cells and generation of reactive oxygen species, which was partly abolished after the injection of PC61 antibody. Importantly, simvastatin increased the number of Tregs and the levels of Treg-associated cytokines (TGF-β and IL-10) and decreased the level of IL-17 both in aortic tissues and serum. Interestingly, simvastatin attenuated Ang II-induced gut microbial dysbiosis, which might be associated with the accumulation of Tregs. In conclusion, simvastatin therapy prevented the development of AAA induced by Ang II in ApoE^-/- mice, which might be partly due to the induction of Treg accumulation. In addition, simvastatin regulated gut microbial dysbiosis, which might also be associated with Treg generation.

Association of TGF-β Canonical Signaling-Related Core Genes With Aortic Aneurysms and Aortic Dissections

Transforming growth factor-beta (TGF-β) signaling is essential for the maintenance of the normal structure and function of the aorta. It includes SMAD-dependent canonical pathways and noncanonical signaling pathways. Accumulated genetic evidence has shown that TGF-β canonical signaling-related genes have key roles in aortic aneurysms (AAs) and aortic dissections and many gene mutations have been identified in patients, such as those for transforming growth factor-beta receptor one TGFBR1, TGFBR2, SMAD2, SMAD3, SMAD4, and SMAD6. Aortic specimens from patients with these mutations often show paradoxically enhanced TGF-β signaling. Some hypotheses have been proposed and new AA models in mice have been constructed to reveal new mechanisms, but the role of TGF-β signaling in AAs is controversial. In this review, we focus mainly on the role of canonical signaling-related core genes in diseases of the aorta, as well as recent advances in gene-mutation detection, animal models, and in vitro studies.

Daxx ameliorates abdominal aortic aneurysm through inhibiting the TGF-β1-mediated PI3K/AKT/ID2 signaling pathway

Background

Abdominal aortic aneurysm (AAA) is a potentially life-threatening vascular abnormality, that, if ruptured, is almost universally fatal without repair, and is associated with up to 50% mortality even if repaired in hospital. To date, there is no drug therapy that has clinically proven benefit to reduce or prevent expansion of AAA. The aim of this study was to investigate whether Daxx could affect AAA through inhibiting the PI3K/AKT/ID2 signaling pathway mediated by transforming growth factor β-1 (TGFβ1).

Methods

The AAA model was constructed by injecting angiotensin Ⅱ (Ang-Ⅱ) into rats, and the Daxx lentivirus vector was constructed. Hematoxylin and eosin (HE) staining was used to detect the wall thickness of the abdominal aorta in rats. The gene and protein expressions in abdominal aortic tissues were detected utilizing western blot, immunohistochemistry (IHC) and fluorescence quantitative real-time polymerase chain reaction (qRT-PCR). Finally, the concentration of TGF-β1 in abdominal aortic tissue was determined by ELISA.

Results

The abdominal aortic wall thickness was decreased in the Daxx expression group (by HE staining), and Daxx overexpression markedly reduced the protein expression levels of MMP2 and MMP9. Proteins related to the PI3K/AKT/ID2 signaling pathway were highly enhanced in the aneurysm wall of rats, but were reduced following Daxx addition. Moreover, Daxx reduced the damage to elastin (by IHC), and the expression levels of α-SMA and SM22α were up-regulated by Daxx (by qRT-PCR). The concentration of TGF-β1 was correlated with the activation of the PI3K/AKT/ID2 signaling pathway (by ELISA), whereas AKT overexpression weakened the inhibitory effect of Daxx.

Conclusion

Daxx ameliorated several mechanisms that contributed to expansion of AAA suppressing the tissue concentration of TGF-β1, thereby inhibiting the activation of the PI3K/AKT/ID2 signaling pathway. This evidence might form the basis to develop a therapeutic target for AAA.

Adventitial Fibroblasts in Aortic Aneurysm: Unraveling Pathogenic Contributions to Vascular Disease

Aortic aneurysm (AA) is a degenerative vascular disease that involves aortic dilatation, and, if untreated, it can lead to rupture. Despite its significant impact on the healthcare system, its multifactorial nature and elusive pathophysiology contribute to limited therapeutic interventions that prevent the progression of AA. Thus, further research into the mechanisms underlying AA is paramount. Adventitial fibroblasts are one of the key constituents of the aortic wall, and they play an essential role in maintaining vessel structure and function. However, adventitial fibroblasts remain understudied when compared with endothelial cells and smooth muscle cells. Adventitial fibroblasts facilitate the production of extracellular matrix (ECM), providing structural integrity. However, during biomechanical stress and/or injury, adventitial fibroblasts can be activated into myofibroblasts, which move to the site of injury and secrete collagen and cytokines, thereby enhancing the inflammatory response. The overactivation or persistence of myofibroblasts has been shown to initiate pathological vascular remodeling. Therefore, understanding the underlying mechanisms involved in the activation of fibroblasts and in regulating myofibroblast activation may provide a potential therapeutic target to prevent or delay the progression of AA. This review discusses mechanistic insights into myofibroblast activation and associated vascular remodeling, thus illustrating the contribution of fibroblasts to the pathogenesis of AA.

EGR1 and KLF4 as Diagnostic Markers for Abdominal Aortic Aneurysm and Associated With Immune Infiltration

Background

Formation and rupture of abdominal aortic aneurysm (AAA) is fatal, and the pathological processes and molecular mechanisms underlying its formation and development are unclear. Perivascular adipose tissue (PVAT) has attracted extensive attention as a newly defined secretory organ, and we aim to explore the potential association between PVAT and AAA.

Methods

We analyzed gene expression and clinical data of 30 PVAT around AAA and 30 PVAT around normal abdominal aorta (NAA). The diagnostic markers and immune cell infiltration of PVAT were further investigated by WGCNA, CIBERSORT, PPI, and multiple machine learning algorisms (including LASSO, RF, and SVM). Subsequently, eight-week-old C57BL/6 male mice (n = 10) were used to construct AAA models, and aorta samples were collected for molecular validation. Meanwhile, fifty-five peripheral venous blood samples from patients (AAA vs. normal: 40:15) in our hospital were used as an inhouse cohort to validate the diagnostic markers by qRT-PCR. The diagnostic efficacy of biomarkers was assessed by receiver operating characteristic (ROC) curve, area under the ROC (AUC), and concordance index (C-index).

Results

A total of 75 genes in the Grey60 module were identified by WGCNA. To select the genes most associated with PVAT in the grey60 module, three algorithms (including LASSO, RF, and SVM) and PPI were applied. EGR1 and KLF4 were identified as diagnostic markers of PVAT, with high accurate AUCs of 0.916, 0.926, and 0.948 (combined two markers). Additionally, the two biomarkers also displayed accurate diagnostic efficacy in the mice and inhouse cohorts, with AUCs and C-indexes all >0.8. Compared with the NAA group, PVAT around AAA was more abundant in multiple immune cell infiltration. Ultimately, the immune-related analysis revealed that EGR1 and KLF4 were associated with mast cells, T cells, and plasma cells.

Conclusion

EGR1 and KLF4 were diagnostic markers of PVAT around AAA and associated with multiple immune cells.

POU class 2 homeobox associating factor 1 (POU2AF1) participates in abdominal aortic aneurysm enlargement based on integrated bioinformatics analysis

Abdominal aortic aneurysm (AAA) is life-threatening, its natural course is progressively sac expansion and rupture. Elegant studies have been conducted to investigate the molecular markers associated with AAA growth and expansion, this topic however, still needs to be further elucidated. This study aimed to identify potential genes for AAA growth and expansion based on comprehensive bioinformatics approaches. Firstly, 29 up-regulated genes were identified through DEGs analysis between large AAA and small AAA in GSE57691. Secondly, signed WGCNA analysis was conducted based on GSE57691 and the green module was found to exhibit the topmost correlation with large AAA as well as AAA, 133 WGCNA hub genes were further identified. Merged gene set including 29 up-regulated DEGs and 858 green module genes was subjected to constructing a PPI network where 195 PPI hub genes were identified. Subsequently, 4 crucial genes including POU2AF1, FCRLA, CD79B, HLA-DOB were recognized by Venn plot. In addition, by using GSE7084 and GSE98278 for verification, POU2AF1 showed potential diagnostic value between AAA and normal groups, and exhibited a significant higher expression level in large AAA samples compared with small AAA samples. Furthermore, immunohistochemistry results indicated up-regulation of POU2AF1 in large AAA samples than small AAA samples, which implies POU2AF1 may be a key regulator in AAA enlargement and growth. In summary, this study indicates that POU2AF1 has great predictive value for the expansion of AAA, and may contribute to the further exploration of pathogenesis and progression of AAA.