Patient-derived microphysiological model identifies the therapeutic potential of metformin for thoracic aortic aneurysm

METTL14 promotes ferroptosis in smooth muscle cells during thoracic aortic aneurysm by stabilizing the m6A modification of ACSL4

Thoracic aortic aneurysm (TAA) is a vascular disease associated with high mortality rates. Ferroptosis has been shown to mediate the transformation of vascular smooth muscle cells (VSMCs). However, the regulatory mechanisms by which ferroptosis influences TAA remain unclear. In this study, we induced TAA mouse models using angiotensin II (Ang II) and evaluated the impact of ferroptosis on the pathological changes observed in TAA mice, employing liproxstatin-1 as a treatment. In addition, we assessed the regulatory effect of METTL14 on the ferroptosis of VSMCs after treating them with a ferroptosis activator (imidazole ketone erastin, IKE). RNA binding protein immunoprecipitation (RIP) and RNA pull-down assays were conducted to investigate the interaction between acyl-CoA synthase long-chain family member 4 (ACSL4) mRNA and the proteins METTL14 or IGF2BP2. The results indicated that the level of ferroptosis was elevated in the thoracic aorta of TAA mice, and METTL14 was upregulated in TAA models and IKE-induced VSMCs. Knockdown of METTL14 was found to inhibit the progression of TAA by reducing the ferroptosis of VSMCs. Furthermore, IGF2BP2 recognized METTL14-modified ACSL4 mRNA and regulated its stability, thereby mediating the ferroptosis of VSMCs. Collectively, the effects of METTL14 on VSMC ferroptosis present therapeutic potential for the treatment of TAA.NEW & NOTEWORTHY Our study confirmed that METTL14 can induce ferroptosis in vascular smooth muscle cells during the progression of thoracic aortic aneurysm by mediating the m6A modification of ACSL4 mRNA.

Knowledge mapping of macrophage and its role in aneurysm from 1999 to 2022: A bibliometric analysis

Background

Various factors play crucial roles in aneurysm development and prognosis. Macrophages have recently emerged as a major research focus. Despite the numerous studies on the role and function of macrophages in aneurysm pathogenesis, no bibliometric analyses have focused on this topic.

Objective

This study aimed to analyze articles related to macrophages and aneurysms to reveal trends, hotspots, and new frontiers in macrophage-related aneurysm research.

Methods

We retrieved and incorporated 1211 articles from the Science Citation Index Expanded database of the Web of Science Core Collection between 1999 and 2022. The data were analyzed and visualized using CiteSpace and VOSviewer, and Microsoft Excel 2019 was used to plot the data.

Results

The most influential articles were published between 1999 and 2022, with a total citation count of 43870. This study encompassed a comprehensive analysis of 74 research directions. The year with the highest number of publications was 2021 when 109 articles were published. 'ARTERIOSCLEROSIS THROMBOSIS AND VASCULAR BIOLOGY' journal has made significant contributions by publishing the highest number of articles (99 articles), while funding support primarily came from the National Institutes of Health and United States Department of Health and Human Services. The United States exerted a substantial influence within this field, with a total publication count of 453 publications and the highest centrality value (0.63). Recent studies have focused on understanding the developmental processes underlying aneurysms and devising preventive measures to effectively impede disease progression.

Conclusions

Our analysis demonstrates the rapid growth in research exploring the relationship between macrophages and aneurysms over the past two decades. Continued exploration and collaboration among different specialties and manufacturers will facilitate innovative approaches for effective management strategies that target patients with diverse forms of aneurysms.

Costunolide mitigates inflammation and promotes extracellualr matrix integrity of thoracic aortic dissection by inhibiting NF-κB signaling

BACKGROUND

Thoracic aortic dissection (TAD) is one of the most fatal cardiovascular diseases. One of its important pathological characteristics is the local inflammatory response. Many studies have found that Macrophage polarization plays an extremely critical role in the inflammatory progression and tissue remodeling of TAD. Costunolide (CTD) has an improving effect on oxidative stress and inflammation in the body. However, whether it can promote the integrity of extracellular matrix in Aortic dissection and its mechanism are still unclear.

METHODS

The male C57BL/6J mice were used to construct an animal model of TAD with β-aminopropionitrile (BAPN) (100 mg/kg/day, lasting for 28 days), and then CTD (10 mg/kg or 100 mg/kg) was injected intraperitoneally for 28 days to check the survival rate, TAD incidence, aortic morphology and other indicators of the mice. Using hematoxylin-eosin (HE), Masson, Elastin van Gieson (EVG) staining, immunofluorescence (IF), and immunohistochemical staining, the study aimed to determine the therapeutic effects of CTD on an animal model with BAPN-induced TAD. To enhance the examination of the regulatory mechanism of CTD, we conducted transcriptome sequencing on arterial tissues of mice in both the BAPN group and the BAPN + CTD100 group. Next, ANG II were used to construct TAD model in vascular smooth muscle cells (VMSCs). The effects of CTD on the proliferation, migration, invasion, and apoptosis of ANG II-induced cells are to be detected. The expression of MMP2, MMP9, P65, and p-P65 in each group will be examined using Western blot. Finally, the overexpression of IκB kinaseβ (IKKβ) will be established in VMSCs cells to further explore the protective function of CTD.

RESULTS

The result showed that CTD significantly inhibited BAPN induced mortality and TAD incidence in the animal model, improved aortic vascular morphology, promoted the integrity of extracellular matrix in TAD, reduced tissue inflammation, reduced the accumulation of M1 macrophage, promoted M2 macrophage polarization, and reduced the expression of NF-κB pathway related proteins. Mechanistically, CTD significantly weakened the proliferation, migration, invasion, and apoptosis. p-P65 protein expression of TAD cells were induced by ANG II and IKK-β.

CONCLUSION

CTD has the potential to alleviate inflammation, VSMC apoptosis, MMP2/9 levels, and enhance extracellular matrix integrity in TAD by inhibiting the NF-κB signaling pathway.

Metformin Therapeutic Targets for Aortic Aneurysms: A Mendelian Randomization and Colocalization Study

Background

Identifying effective pharmacological interventions to prevent the progressive enlargement and rupture of aortic aneurysms (AAs) is critical. Previous studies have suggested links between metformin use and a decreased incidence of AAs. In this study, we employed Mendelian randomization (MR) to investigate causal effects of metformin's targets on AA risk and to explore the underlying mechanisms underlying these effects.

Methods

To examine the relationship between metformin use and AA risk, we implemented both two-sample MR and multivariable MR analyses. Utilizing genetic instrumental variables, we retrieved cis-expression quantitative trait loci (cis-eQTL) data for potential targets of metformin from the Expression Quantitative Trait Loci Genetics Consortium (eQTLGen) Consortium and Genotype-Tissue Expression (GTEx) project. Colocalization analysis was employed to ascertain the probability of shared causal genetic variants between single nucleotide polymorphisms (SNPs) associated with eQTLs and AA.

Results

Our findings reveal that metformin use reduces AA risk, exhibiting a protective effect with an odds ratio (OR) of 4.88 × 10 - 3 (95% confidence interval [CI]: 7.30 × 10 - 5 -0.33, p = 0.01). Furthermore, the protective effect of type 2 diabetes on AA risk appears to be driven by metformin use ( OR MVMR = 1.34 × 10 - 4 , 95% CI: 3.97 × 10 - 8 -0.45, p = 0.03). Significant Mendelian randomization (MR) results were observed for the expression of two metformin-related genes in the bloodstream: NADH:ubiquinone oxidoreductase subunit A6 (NDUFA6) and cytochrome b5 type B (CYB5B), across two independent datasets ( OR CYB5B = 1.35, 95% CI: 1.20-1.51, p = 2.41 × 10 - 7 ; OR NDUFA6 = 1.12; 95% CI: 1.07-1.17, p = 1.69 × 10 - 6 ). The MR analysis of tissue-specific expression also demonstrated a positive correlation between increased NDUFA6 expression and heightened AA risk. Lastly, NDUFA6 exhibited evidence of colocalization with AA.

Conclusions

Our study suggests that metformin may play a significant role in lowering the risk of AA. This protective effect could potentially be linked to the mitigation of mitochondrial and immune dysfunction. Overall, NDUFA6 has emerged as a potential mechanism through which metformin intervention may confer AA protection.

The activator protein-1 complex governs a vascular degenerative transcriptional programme in smooth muscle cells to trigger aortic dissection and rupture

BACKGROUND AND AIMS

Stanford type A aortic dissection (AD) is a degenerative aortic remodelling disease marked by an exceedingly high mortality without effective pharmacologic therapies. Smooth muscle cells (SMCs) lining tunica media adopt a range of states, and their transformation from contractile to synthetic phenotypes fundamentally triggers AD. However, the underlying pathomechanisms governing this population shift and subsequent AD, particularly at distinct disease temporal stages, remain elusive.

METHODS

Ascending aortas from nine patients undergoing ascending aorta replacement and five individuals undergoing heart transplantation were subjected to single-cell RNA sequencing. The pathogenic targets governing the phenotypic switch of SMCs were identified by trajectory inference, functional scoring, single-cell regulatory network inference and clustering, regulon, and interactome analyses and confirmed using human ascending aortas, primary SMCs, and a β-aminopropionitrile monofumarate-induced AD model.

RESULTS

The transcriptional profiles of 93 397 cells revealed a dynamic temporal-specific phenotypic transition and marked elevation of the activator protein-1 (AP-1) complex, actively enabling synthetic SMC expansion. Mechanistically, tumour necrosis factor signalling enhanced AP-1 transcriptional activity by dampening mitochondrial oxidative phosphorylation (OXPHOS). Targeting this axis with the OXPHOS enhancer coenzyme Q10 or AP-1-specific inhibitor T-5224 impedes phenotypic transition and aortic degeneration while improving survival by 42.88% (58.3%-83.3% for coenzyme Q10 treatment), 150.15% (33.3%-83.3% for 2-week T-5224), and 175.38% (33.3%-91.7% for 3-week T-5224) in the β-aminopropionitrile monofumarate-induced AD model.

CONCLUSIONS

This cross-sectional compendium of cellular atlas of human ascending aortas during AD progression provides previously unappreciated insights into a transcriptional programme permitting aortic degeneration, highlighting a translational proof of concept for an anti-remodelling intervention as an attractive strategy to manage temporal-specific AD by modulating the tumour necrosis factor-OXPHOS-AP-1 axis.

Animal Models, Pathogenesis, and Potential Treatment of Thoracic Aortic Aneurysm

Thoracic aortic aneurysm (TAA) has a prevalence of 0.16-0.34% and an incidence of 7.6 per 100,000 person-years, accounting for 1-2% of all deaths in Western countries. Currently, no effective pharmacological therapies have been identified to slow TAA development and prevent TAA rupture. Large TAAs are treated with open surgical repair and less invasive thoracic endovascular aortic repair, both of which have high perioperative mortality risk. Therefore, there is an urgent medical need to identify the cellular and molecular mechanisms underlying TAA development and rupture to develop new therapies. In this review, we summarize animal TAA models including recent developments in porcine and zebrafish models: porcine models can assess new therapeutic devices or intervention strategies in a large mammal and zebrafish models can employ large-scale small-molecule suppressor screening in microwells. The second part of the review covers current views of TAA pathogenesis, derived from recent studies using these animal models, with a focus on the roles of the transforming growth factor-beta (TGFβ) pathway and the vascular smooth muscle cell (VSMC)-elastin-contractile unit. The last part discusses TAA treatment options as they emerge from recent preclinical studies.

Organ-on-a-chip meets artificial intelligence in drug evaluation

Drug evaluation has always been an important area of research in the pharmaceutical industry. However, animal welfare protection and other shortcomings of traditional drug development models pose obstacles and challenges to drug evaluation. Organ-on-a-chip (OoC) technology, which simulates human organs on a chip of the physiological environment and functionality, and with high fidelity reproduction organ-level of physiology or pathophysiology, exhibits great promise for innovating the drug development pipeline. Meanwhile, the advancement in artificial intelligence (AI) provides more improvements for the design and data processing of OoCs. Here, we review the current progress that has been made to generate OoC platforms, and how human single and multi-OoCs have been used in applications, including drug testing, disease modeling, and personalized medicine. Moreover, we discuss issues facing the field, such as large data processing and reproducibility, and point to the integration of OoCs and AI in data analysis and automation, which is of great benefit in future drug evaluation. Finally, we look forward to the opportunities and challenges faced by the coupling of OoCs and AI. In summary, advancements in OoCs development, and future combinations with AI, will eventually break the current state of drug evaluation.