Effects of Extracellular Matrix Softening on Vascular Smooth Muscle Cell Dysfunction

Dissecting causal relationships between immune cells, blood metabolites, and aortic dissection: A mediation Mendelian randomization study

Background

There exists a robust correlation between the infiltration of immune cells and the pathogenesis of aortic dissection (AD). Moreover, blood metabolites serve as immunomodulatory agents within the organism, influencing the immune system's response and potentially playing a role in the development of AD. Nevertheless, the intricate genetic causal nexus between specific immune cells, blood metabolites, and AD remains partially elucidated.

Objectives

This study aims to elucidate the causal relationships between specific immune cell types and the risk of developing AD, mediated by blood metabolites, using Mendelian Randomization (MR) methods.

Methods

We undertook a comprehensive investigation of 731 immune cell types through the analysis of published genome-wide association studies (GWAS). Our methodology hinged on the application of two-sample Mendelian randomization (MR) and mediator MR analyses, prioritizing blood metabolites as potential intermediary factors and AD as the principal outcome of interest. The primary statistical method employed was inverse variance-weighted estimation, complemented by a variety of sensitivity analyses to reinforce our conclusions. The entirety of our statistical analyses was executed on the R software platform.

Results

Our analyses elucidated that three immune cell types exhibited a positive correlation with the incidence of AD, whereas two immune cell types were inversely associated with AD risk. Significantly, our mediation Mendelian randomization (MR) findings identified Benzoate as a pivotal mediator in the influence of CD19 on IgD - CD38br cells on AD, with a mediation proportion of 5.38 %. Additionally, N-acetylproline was determined to mediate the effect of CD24 on IgD- CD38- cells on AD, accounting for a mediation proportion of 13.70 %. Furthermore, Carnitine C5:1 was found to mediate the effect of CD28 on secreting T regulatory (Treg) cells on AD, with a mediation proportion of 17.80 %.

Conclusions

These findings offer a nuanced understanding of the pathophysiological mechanisms underlying AD, thereby advancing the precision medicine paradigm in the clinical management of AD.Abbreviations: AD: aortic dissection; AA: aortic aneurysm; GWAS: genome-wide association study; MR: Mendelian randomization; TSMR: two-step Mendelian randomization; Treg: secreting T regulatory cell; VSMC: vascular smooth muscle cell; MMP: matrix metalloproteinase; ROS: reactive oxygen species; IV: instrumental variable; SNP: single-nucleotide polymorphism; IVW: inverse variance weighted; LDSC: linkage disequilibrium score regression; OR: odds ratio; CI: confidence interval; LD: linkage disequilibrium; AC: absolute cell; MFI: median fluorescence intensity; MP: morphological parameter; RC: relative cell; CLSA: Canadian Longitudinal Study of Aging; Lp(a): Lipoprotein a; OxPL: oxidised phospholipid; NMDAR: N-methyl-d-aspartate glutamate receptor; STROBE-MR: Strengthening the Reporting of Observational Studies in Epidemiology using Mendelian Randomization.

Early matrix softening contributes to vascular smooth muscle cell phenotype switching and aortic dissection through down-regulation of microRNA-143/145

Thoracic aortic dissection (TAD) is characterized by extracellular matrix (ECM) dysregulation. Aberrations in the ECM stiffness can lead to changes in cellular functions. However, the mechanism by which ECM softening regulates vascular smooth muscle cell (VSMCs) phenotype switching remains unclear. To understand this mechanism, we cultured VSMCs in a soft extracellular matrix and discovered that the expression of microRNA (miR)-143/145, mediated by activation of the AKT signalling pathway, decreased significantly. Furthermore, overexpression of miR-143/145 reduced BAPN-induced aortic softening, switching the VSMC synthetic phenotype and the incidence of TAD in mice. Additionally, high-throughput sequencing of immunoprecipitated RNA indicated that the TEA domain transcription factor 1 (TEAD1) is a common target gene of miR-143/145, which was subsequently verified using a luciferase reporter assay. TEAD1 is upregulated in soft ECM hydrogels in vitro, whereas the switch to a synthetic phenotype in VSMCs decreases after TEAD1 knockdown. Finally, we verified that miR-143/145 levels are associated with disease severity and prognosis in patients with thoracic aortic dissection. ECM softening, as a result of promoting the VSMCs switch to a synthetic phenotype by downregulating miR-143/145, is an early trigger of TAD and provides a therapeutic target for this fatal disease. miR-143/145 plays a role in the early detection of aortic dissection and its severity and prognosis, which can offer information for future risk stratification of patients with dissection.

Elucidating VSMC phenotypic transition mechanisms to bridge insights into cardiovascular disease implications

Cardiovascular diseases (CVD) are the leading cause of death worldwide, despite advances in understanding cardiovascular health. Significant barriers still exist in effectively preventing and managing these diseases. Vascular smooth muscle cells (VSMCs) are crucial for maintaining vascular integrity and can switch between contractile and synthetic functions in response to stimuli such as hypoxia and inflammation. These transformations play a pivotal role in the progression of cardiovascular diseases, facilitating vascular modifications and disease advancement. This article synthesizes the current understanding of the mechanisms and signaling pathways regulating VSMC phenotypic transitions, highlighting their potential as therapeutic targets in cardiovascular disease interventions.

Murine double minute 2-mediated estrogen receptor 1 degradation activates macrophage migration inhibitory factor to promote vascular smooth muscle cell dedifferentiation and oxidative stress during thoracic aortic aneurysm progression

Estrogen receptor 1 (ESR1) has been recently demonstrated as a potential diagnostic biomarker for thoracic aortic aneurysm (TAA). However, its precise role in the progression of TAA remains unclear. In this study, TAA models were established in ApoE-knockout mice and primary mouse vascular smooth muscle cells (VSMCs) through treatment with angiotensin (Ang) II. Our findings revealed a downregulation of ESR1 in Ang II-induced TAA mice and VSMCs. Upregulation of ESR1 mitigated expansion and cell apoptosis in the mouse aorta, reduced pathogenetic transformation of VSMCs, and reduced inflammatory infiltration and oxidative stress both in vitro and in vivo. Furthermore, we identified macrophage migration inhibitory factor (MIF) as a biological target of ESR1. ESR1 bound to the MIF promoter to suppress its transcription. Artificial MIF restoration negated the mitigating effects of ESR1 on TAA. Additionally, we discovered that murine double minute 2 (MDM2) was highly expressed in TAA models and mediated protein degradation of ESR1 through ubiquitination modification. Silencing of MDM2 reduced VSMC dedifferentiation and suppressed oxidative stress. However, these effects were reversed upon further silencing of ESR1. In conclusion, this study demonstrates that MDM2 activates MIF by mediating ESR1 degradation, thus promoting VSMC dedifferentiation and oxidative stress during TAA progression.

Independent and Interactive Roles of Immunity and Metabolism in Aortic Dissection

Aortic dissection (AD) is a cardiovascular disease that seriously endangers the lives of patients. The mortality rate of this disease is high, and the incidence is increasing annually, but the pathogenesis of AD is complicated. In recent years, an increasing number of studies have shown that immune cell infiltration in the media and adventitia of the aorta is a novel hallmark of AD. These cells contribute to changes in the immune microenvironment, which can affect their own metabolism and that of parenchymal cells in the aortic wall, which are essential factors that induce degeneration and remodeling of the vascular wall and play important roles in the formation and development of AD. Accordingly, this review focuses on the independent and interactive roles of immunity and metabolism in AD to provide further insights into the pathogenesis, novel ideas for diagnosis and new strategies for treatment or early prevention of AD.

Resveratrol Inhibits Abdominal Aortic Aneurysm Progression by Reducing Extracellular Matrix Degradation, Apoptosis, Autophagy, and Inflammation of Vascular Smooth Muscle Cells via Upregulation of HMOX1

OBJECTIVE

This study aimed to explore the therapeutic effect of resveratrol (RES) against abdominal aortic aneurysm (AAA) and the role of HMOX1 underlying this effect.

METHODS

Vascular smooth muscle cells (VSMCs) were induced by angiotensin II (Ang II) to construct the microenvironment of AAA. HMOX1 expression was downregulated by the short hairpin ribonucleic acid (RNA) specific to HMOX1 in RES-pretreated VSMCs. The levels of matrix metalloproteinase (MMP)-2, MMP-9, and elastin were measured by quantitative reverse transcription polymerase chain reaction (qRT-PCR) and western blot. Apoptosis rate was detected. The levels of apoptosis-related proteins (caspase-3 and Bax/Bcl-2), inflammatory cytokines (interleukin [IL]-6, tumor necrosis factor [TNF]-α, and IL-1β), and autophagy-related proteins (Beclin 1, light chain 3 [LC3] II/I, and p62) were detected by western blot. The secretion of inflammatory factors in cell supernatant was detected by enzyme-linked immunosorbent assay (ELISA). The number of autophagic vesicles in VSMCs was observed and analyzed by transmission electron microscopy. A rat model of pancreatic elastase-induced AAA was established to verify the effect and action mechanism of RES.

RESULTS

Stimulation of Ang II increased the messenger RNA (mRNA) and protein levels of MMP-2 and MMP-9, decreased elastin expression, and enhanced apoptosis, secretion of inflammatory factors, and autophagy in VSMCs, whereas RES pretreatment ameliorated Ang II-induced VSMC dysfunction. In addition, HMOX1 mRNA and heme oxygenase-1 (HO-1) protein levels were significantly increased in VSMCs pretreated with RES compared with Ang II treatment alone. Silencing of HMOX1 abolished the effects of RES on VSMC dysfunction. Consistently, RES suppressed the development of AAA in rats by increasing the expression of HMOX1.

CONCLUSION

Resveratrol protects against AAA by inhibiting extracellular matrix degradation, apoptosis, autophagy, and inflammation of VSMCs via HMOX1 upregulation.

CLINICAL IMPACT

Our study found that angiotensin II (Ang II) stimulated increased the levels of MMP-2 and MMP-9 in vascular smooth muscle cells (VSMCs), decreased elastin expression, and promoted apoptosis, autophagy occurrence, and secretion of inflammatory factors, while resveratrol (RES) pretreatment improved this effect. In addition, downregulation of HMOX1 expression eliminated the effect of RES on the function of VSMCs. Our study elucidates that RES improves AAA progression through HMOX1 at both cellular and animal levels. This work can help doctors better understand the pathological mechanism of the occurrence and development of AAA, and provide a theoretical basis for clinicians to find better treatment options.

Cellular mechanotransduction in health and diseases: from molecular mechanism to therapeutic targets

Cellular mechanotransduction, a critical regulator of numerous biological processes, is the conversion from mechanical signals to biochemical signals regarding cell activities and metabolism. Typical mechanical cues in organisms include hydrostatic pressure, fluid shear stress, tensile force, extracellular matrix stiffness or tissue elasticity, and extracellular fluid viscosity. Mechanotransduction has been expected to trigger multiple biological processes, such as embryonic development, tissue repair and regeneration. However, prolonged excessive mechanical stimulation can result in pathological processes, such as multi-organ fibrosis, tumorigenesis, and cancer immunotherapy resistance. Although the associations between mechanical cues and normal tissue homeostasis or diseases have been identified, the regulatory mechanisms among different mechanical cues are not yet comprehensively illustrated, and no effective therapies are currently available targeting mechanical cue-related signaling. This review systematically summarizes the characteristics and regulatory mechanisms of typical mechanical cues in normal conditions and diseases with the updated evidence. The key effectors responding to mechanical stimulations are listed, such as Piezo channels, integrins, Yes-associated protein (YAP) /transcriptional coactivator with PDZ-binding motif (TAZ), and transient receptor potential vanilloid 4 (TRPV4). We also reviewed the key signaling pathways, therapeutic targets and cutting-edge clinical applications of diseases related to mechanical cues.

Investigation of electrical stimulation on phenotypic vascular smooth muscle cells differentiation in tissue-engineered small-diameter vascular graft

In the development of vascular tissue engineering, particularly in the case of small diameter vessels, one of the key obstacles is the blockage of these veins once they enter the in vivo environment. One of the contributing factors to this problem is the aberrant proliferation and migration of vascular smooth muscle cells (VSMCs) from the media layer of the artery to the interior of the channel. Two distinct phenotypes have been identified for smooth muscle cells, namely synthetic and contractile. Since the synthetic phenotype plays an essential role in the unusual growth and migration, the aim of this study was to convert the synthetic phenotype into the contractile one, which is a solution to prevent the abnormal growth of VSMCs. To achieve this goal, these cells were subjected to electrical signals, using a 1000 μA sinusoidal stimulation at 10 Hz for four days, with 20 min duration per 24 h. The morphological transformations and changes in the expression of vimentin, nestin, and β-actin proteins were then studied using ICC and flow cytometry assays. Also, the expression of VSMC specific markers such as smooth muscle myosin heavy chain (SMMHC) and smooth muscle alpha-actin (α-SMA) were evaluated using RT-PCR test. In the final phase of this study, the sheep decellularized vessel was employed as a scaffold for seeding these cells. Based on the results, electrical stimulation resulted in some morphological alterations in VSMCs. Furthermore, the observed reductions in the expression levels of vimentin, nestin and β-actin proteins and increase in the expression of SMMHC and α-SMA markers showed that it is possible to convert the synthetic phenotype to the contractile one using the studied regime of electrical stimulation. Finally, it can be concluded that electrical stimulation can significantly affect the phenotype of VSMCs, as demonstrated in this study.

Applying multi-omics techniques to the discovery of biomarkers for acute aortic dissection

Acute aortic dissection (AAD) is a cardiovascular disease that manifests suddenly and fatally. Due to the lack of specific early symptoms, many patients with AAD are often overlooked or misdiagnosed, which is undoubtedly catastrophic for patients. The particular pathogenic mechanism of AAD is yet unknown, which makes clinical pharmacological therapy extremely difficult. Therefore, it is necessary and crucial to find and employ unique biomarkers for Acute aortic dissection (AAD) as soon as possible in clinical practice and research. This will aid in the early detection of AAD and give clear guidelines for the creation of focused treatment agents. This goal has been made attainable over the past 20 years by the quick advancement of omics technologies and the development of high-throughput tissue specimen biomarker screening. The primary histology data support and add to one another to create a more thorough and three-dimensional picture of the disease. Based on the introduction of the main histology technologies, in this review, we summarize the current situation and most recent developments in the application of multi-omics technologies to AAD biomarker discovery and emphasize the significance of concentrating on integration concepts for integrating multi-omics data. In this context, we seek to offer fresh concepts and recommendations for fundamental investigation, perspective innovation, and therapeutic development in AAD.

The Microenvironment That Regulates Vascular Wall Stem/Progenitor Cells in Vascular Injury and Repair

Vascular repair upon injury is a frequently encountered pathology in cardiovascular diseases, which is crucial for the maintenance of arterial homeostasis and function. Stem/progenitor cells located on vascular walls have multidirectional differentiation potential and regenerative ability. It has been demonstrated that stem/progenitor cells play an essential role in the basic medical research and disease treatment. The dynamic microenvironment around the vascular wall stem/progenitor cells (VW-S/PCs) possesses many stem cell niche-like characteristics to support and regulate cells' activities, maintaining the properties of stem cells. Under physiological conditions, vascular homeostasis is a cautiously balanced and efficient interaction between stem cells and the microenvironment. These interactions contribute to the vascular repair and remodeling upon vessel injury. However, the signaling mechanisms involved in the regulation of microenvironment on stem cells remain to be further elucidated. Understanding the functional characteristics and potential mechanisms of VW-S/PCs is of great significance for both basic and translational research. This review underscores the microenvironment-derived signals that regulate VW-S/PCs and aims at providing new targets for the treatment of related cardiovascular diseases.

Stem Cell Based Approaches to Modulate the Matrix Milieu in Vascular Disorders

The extracellular matrix (ECM) represents a complex and dynamic framework for cells, characterized by tissue-specific biophysical, mechanical, and biochemical properties. ECM components in vascular tissues provide structural support to vascular cells and modulate their function through interaction with specific cell-surface receptors. ECM–cell interactions, together with neurotransmitters, cytokines, hormones and mechanical forces imposed by blood flow, modulate the structural organization of the vascular wall. Changes in the ECM microenvironment, as in post-injury degradation or remodeling, lead to both altered tissue function and exacerbation of vascular pathologies. Regeneration and repair of the ECM are thus critical toward reinstating vascular homeostasis. The self-renewal and transdifferentiating potential of stem cells (SCs) into other cell lineages represents a potentially useful approach in regenerative medicine, and SC-based approaches hold great promise in the development of novel therapeutics toward ECM repair. Certain adult SCs, including mesenchymal stem cells (MSCs), possess a broader plasticity and differentiation potential, and thus represent a viable option for SC-based therapeutics. However, there are significant challenges to SC therapies including, but not limited to cell processing and scaleup, quality control, phenotypic integrity in a disease milieu in vivo, and inefficient delivery to the site of tissue injury. SC-derived or -inspired strategies as a putative surrogate for conventional cell therapy are thus gaining momentum. In this article, we review current knowledge on the patho-mechanistic roles of ECM components in common vascular disorders and the prospects of developing adult SC based/inspired therapies to modulate the vascular tissue environment and reinstate vessel homeostasis in these disorders.

ONOO- -mediated oxidative modification of extracellular matrix aggravates atherosclerosis by affecting biological behaviors of vascular smooth muscle cells

Atherosclerosis (AS) is a principal contributor to stroke and coronary heart disease in humans characterized by chronic low-grade inflammation. The extracellular matrix (ECM) plays critical roles in regulating the function of arteries. However, the effect of changes in ECM on AS development is rarely studied. In this context, we intend to study the effect of oxidizing agent peroxynitrite (ONOO^- )-mediated oxidization of ECM proteins on the biological behaviors of vascular smooth muscle cells (SMCs) and the development of AS. AS mouse models were established, and mouse coronary artery smooth muscle cells (MCASMCs) were cultured in vitro to derive ECM (SMC-ECM), which was obtained by deoxycholate (DOC)-based decellularization. Further, MCASMCs were subjected to the determination of ECM oxidative damage and ECM protein structure. Finally, roles of ONOO^- -mediated oxidization of ECM in SMC adhesion and migration and in AS development were explored through Transwell assay, transcriptome sequencing, and gene enrichment analysis. High concentration of ONOO^- was found in the serum of AS mice, and ONOO^- could stimulate the development of AS. SMC-ECM with intact structure can be obtained in vitro by DOC treatment. Functionally, ONOO^- -mediated oxidization destroyed the three-dimensional structure of SMC-ECM proteins, affected SMC adhesion and migration and promoted the absorption efficiency of lipids while reducing the efflux of cholesterol. In addition, the expression of inflammation- and oxidative stress-related genes was significantly increased in ECM subjected to ONOO^- -mediated oxidization, thereby contributing to AS progression. ONOO^- -mediated oxidative modification of ECM aggravates AS by affecting the biological behavior of SMCs.

Comprehensive Analysis of Endoplasmic Reticulum Stress in Intracranial Aneurysm

Background

Aberrant endoplasmic reticulum stress (ERS) plays an important role in multiple cardiovascular diseases. However, their implication in intracranial aneurysms (IAs) remains unclear. We designed this study to explore the general expression pattern and potential functions of ERS in IAs.

Methods

Five Gene Expression Omnibus (GEO) microarray datasets were used as the training cohorts, and 3 GEO RNA sequencing (RNA-seq) datasets were used as the validating cohorts. Differentially expressed genes (DEGs), functional enrichment, Lasso regression, logistic regression, ROC analysis, immune cell profiling, vascular smooth muscle cell (VSMC) phenotyping, weighted gene coexpression network analysis (WGCNA), and protein-protein interaction (PPI) analysis were applied to investigate the role of ERS in IA. Finally, we predicted the upstream transcription factor (TF)/miRNA and potential drugs targeting ERS.

Results

Significant DEGs were majorly associated with ERS, autophagy, and metabolism. Eight-gene ERS signature and IRE1 pathway were identified during the IA formation. WGCNA showed that ERS was highly associated with a VSMC synthesis phenotype. Next, ERS-VSMC-metabolism-autophagy PPI and ERS-TF-miRNA networks were constructed. Finally, we predicted 9 potential drugs targeting ERS in IAs.

Conclusion

ERS is involved in IA formation. Upstream and downstream regulatory networks for ERS were identified in IAs. Novel potential drugs targeting ERS were also proposed, which may delay IA formation and progress.

Molecular feature of arterial remodeling in the brain arteriovenous malformation revealed by arteriovenous shunt rat model and RNA sequencing

PURPOSE

Morphological research suggested the feeding artery of brain arteriovenous malformation (bAVM) had vascular remodeling under the high blood flow; however, the underlying molecular mechanisms were unclear.

METHODS

We constructed 32 simplified AVM rat models in four groups: the control group (n = 6), 1-week high-blood-flow group (n = 9), 3-week high-blood-flow group (n = 7) and 6-week high-blood-flow group (n = 10). The circumference, blood velocity, blood flow, pressure, and wall shear of the feeding artery were measured or calculated. The arterial wall change was observed by Masson staining. RNA sequencing (RNA-seq) of feeding arteries was performed, followed by bioinformatics analysis to detect the potential molecular mechanism for bAVM artery remodeling under the high blood flow.

RESULTS

We observed hemodynamic injury and vascular remodeling on the feeding artery under the high blood flow. RNA-seq showed immune/inflammation infiltration and vascular smooth muscle cell (VSMC) phenotype transformation during remodeling. Weighted gene co-expression network analysis (WGCNA) and time series analysis further identified 27 key genes and pathways involved in remodeling. Upstream miRNA and molecular drugs were predicted targeting these key genes.

CONCLUSIONS

We depicted molecular change of bAVM arterial remodeling via RNA-seq in high-blood-flow rat models. Twenty-seven key genes may regulate immune/inflammation infiltration and VSMC phenotype transform in bAVM arterial remodeling.

β-Aminopropionitrile-induced aortic aneurysm and dissection in mice

The mechanistic basis for the formation of aortic aneurysms and dissection needs to be elucidated to facilitate the development of effective medications. β-Aminopropionitrile administration in mice has been used frequently to study the pathologic features and mechanisms of aortic aneurysm and dissection. This mouse model mimics several facets of the pathology of human aortic aneurysms and dissection, although many variables exist in the experimental design and protocols that must be resolved to determine its application to the human disease. In the present brief review, we have introduced the development of this mouse model and provided insights into understanding its pathologic features.

The Phenotypic Responses of Vascular Smooth Muscle Cells Exposed to Mechanical Cues

During the development of atherosclerosis and other vascular diseases, vascular smooth muscle cells (SMCs) located in the intima and media of blood vessels shift from a contractile state towards other phenotypes that differ substantially from differentiated SMCs. In addition, these cells acquire new functions, such as the production of alternative extracellular matrix (ECM) proteins and signal molecules. A similar shift in cell phenotype is observed when SMCs are removed from their native environment and placed in a culture, presumably due to the absence of the physiological signals that maintain and regulate the SMC phenotype in the vasculature. The far majority of studies describing SMC functions have been performed under standard culture conditions in which cells adhere to a rigid and static plastic plate. While these studies have contributed to discovering key molecular pathways regulating SMCs, they have a significant limitation: the ECM microenvironment and the mechanical forces transmitted through the matrix to SMCs are generally not considered. Here, we review and discuss the recent literature on how the mechanical forces and derived biochemical signals have been shown to modulate the vascular SMC phenotype and provide new perspectives about their importance.