Interleukin-6 downregulated vascular smooth muscle cell contractile proteins via ATG4B-mediated autophagy in thoracic aortic dissection

Relationship between inflammatory-related cytokines with aortic dissection

Aortic dissection, characterized by severe intramural hematoma formation and acute endometrial rupture, is caused by excessive bleeding within the aortic wall or a severe tear within the intimal layer of the aorta, which subsequently promotes the separation or dissection in the layers of the aortic wall. Epidemiological surveys showed that aortic dissection was most observed among those patients from 55 to 80 years of age, with a prevalence of approximately 40 cases per 100,000 individuals per year, posing serious risks to future health and leading to high mortality. Other risk factors of aortic dissection progression contained dyslipidemia, hypertension, and genetic disorders, such as Marfan syndrome. Currently, emerging evidence indicates the pathological progression of aortic dissection is significantly complicated, which is correlated with the aberrant infiltration of pro-inflammatory cells into the aortic wall, subsequently facilitating the apoptosis of vascular smooth muscle cells (VSMCs) and inducing the aberrant expression of pro-inflammatory cytokines, including tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and interferon (IF). Other pro-inflammatory-related cytokines, including the colony-stimulating factor (CSF), chemotactic factor, and growth factor (GF), played an essential function in facilitating aortic dissection. Multiple studies focused on the important relationship between pro-inflammatory cytokines and aortic dissection, which could deepen the understanding of aortic dissection and further guide the therapeutic strategies in clinical practice. The present review elucidated pro-inflammatory cytokines' functions in modulating the risk of aortic dissection are summarized. Moreover, the emerging evidence that aimed to elucidate the potential mechanisms wherebyvarious pro-inflammatory cytokines affected the pathological development of aortic dissection was also listed.

Bioinformatics analysis of aging-related genes in thoracic aortic aneurysm and dissection

Objective

Thoracic aortic aneurysm and dissection (TAAD) is a cardiovascular disease with a high mortality rate. Aging is an important risk factor for TAAD. This study explored the relationship between aging and TAAD and investigated the underlying mechanisms, which may contribute to the diagnosis and treatment of TAAD.

Methods

Human aging genes were obtained from the Aging Atlas official website. Various datasets were downloaded from the GEO database:the human TAAD dataset GSE52093 were used for screening differentially expressed genes (DEGs); GSE137869, GSE102397 and GSE153434 were used as validation sets, and GSE9106 was used for diagnostic prediction of receiver operating characteristic (ROC) curves. Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), Gene Set Enrichment Analysis (GSEA), and protein-protein interaction (PPI) network analysis were used to screen differentially co-expressed genes from human aging genes and TAAD. Using five methods of the cytoHubba plugin in Cytoscape software (Degree, Closeness, EPC, MNC, Radiality), hub genes were identified from the differentially co-expressed genes. Single-cell RNA sequencing was used to verify the expression levels of hubgenes in different cell types of aortic tissue. ROC curves were used to further screen for diagnostic genes.

Results

A total of 70 differentially co-expressed genes were screened from human aging genes and DEGs in human TAAD dataset GSE52093. GO enrichment analysis revealed that the DEGs played a major role in regulating DNA metabolism and damaged DNA binding. KEGG enrichment analysis revealed enrichment in the longevity regulating pathway, cellular senescence, and HIF-1 signaling pathway. GSEA indicated that the DEGs were concentrated in the cell cycle and aging-related p53 signaling pathway. The five identified hubgenes were MYC, IL6, HIF1A, ESR1, and PTGS2. Single-cell sequencing of the aging rat aorta showed that hubgenes were expressed differently in different types of cells in aortic tissue. Among these five hubgenes, HIF1A and PTGS2 were validated in the aging dataset GSE102397; MYC, HIF1A and ESR1 were validated in the TAAD dataset GSE153434. The combined area under the diagnostic ROC curve (AUC) values for the five hub genes were >0.7 in the testing and training sets of the dataset GSE9106. The combined AUC values of MYC and ESR1 were equal to the combin ed AUC values of the five hub genes.

Conclusion

The HIF-1 signaling pathway may play an important role in TAAD and aging. MYC and ESR1 may have diagnostic value for aging-related TAAD.

The role of vascular smooth muscle cells in the development of aortic aneurysms and dissections

BACKGROUND

Aortic aneurysms (AA) are pathological dilations of the aorta, associated with an overall mortality rate up to 90% in case of rupture. In addition to dilation, the aortic layers can separate by a tear within the layers, defined as aortic dissections (AD). Vascular smooth muscle cells (vSMC) are the predominant cell type within the aortic wall and dysregulation of vSMC functions contributes to AA and AD development and progression. However, since the exact underlying mechanism is poorly understood, finding potential therapeutic targets for AA and AD is challenging and surgery remains the only treatment option.

METHODS

In this review, we summarize current knowledge about vSMC functions within the aortic wall and give an overview of how vSMC functions are altered in AA and AD pathogenesis, organized per anatomical location (abdominal or thoracic aorta).

RESULTS

Important functions of vSMC in healthy or diseased conditions are apoptosis, phenotypic switch, extracellular matrix regeneration and degradation, proliferation and contractility. Stressors within the aortic wall, including inflammatory cell infiltration and (epi)genetic changes, modulate vSMC functions and cause disturbance of processes within vSMC, such as changes in TGF-β signalling and regulatory RNA expression.

CONCLUSION

This review underscores a central role of vSMC dysfunction in abdominal and thoracic AA and AD development and progression. Further research focused on vSMC dysfunction in the aortic wall is necessary to find potential targets for noninvasive AA and AD treatment options.

Dysregulation of interaction between LOXhigh fibroblast and smooth muscle cells contributes to the pathogenesis of aortic dissection

Rationale: While cell-cell interaction plays a critical role in physiology and disease, a comprehensive understanding of its dynamics in vascular homeostasis and diseases is yet absent. Methods: Here, by use of single-cell RNA-sequencing and multi-color staining, we delineate the cellular composition and spatial characterization of human aorta with or without aortic dissection (AD). Results: Scrutinization of cell subtype alterations revealed significantly changed fibroblast (FB)-smooth muscle cell (SMC) interactions in AD. Of these cellular interactions, LOX^high fibroblast (fibroblast subtype 2, FB2) in diseased state exerted the most pronounced effects on pathological deterioration of SMCs in AD. In addition, pharmacologically targeting the BMP (bone morphogenetic protein) signaling pathway effectively suppressed FB2 state transition and reduced AD incidence in mice. Finally, COL5A1 (collagen type V alpha 1 chain), one of the secreted proteins released from FB2, was significantly higher in the plasma of AD patients than in control patients, suggesting its potential use as a biomarker for AD diagnosis. Conclusions: Our work not only identified a pivotal role of a specific FB subtype in AD progression, but also shed light on cell interaction dynamics in vascular diseases.

Targeting regulated cell death in aortic aneurysm and dissection therapy

Regulated cell death (RCD) is a basic biological phenomenon associated with cell and tissue homeostasis. Recent studies have enriched our understanding of RCD, and many novel cell death types, such as ferroptosis and pyroptosis, have been discovered and defined. Aortic aneurysm and dissection (AAD) is a life-threatening condition, but the pathogenesis remains largely unclear. A series of studies have indicated that the death of smooth muscle cells, endothelial cells and inflammatory cells participates in the development of AAD and that corresponding interventions could alleviate disease progression. Many treatments against cell death have been used to impede the process of AAD in vitro and in vivo, which provides strategies to protect against this condition. In this review, we focus on various types of regulated cell death and provide a framework of their roles in AAD, and the information contributes to further exploration of the molecular mechanisms of AAD.

LINC01278 Sponges miR-500b-5p to Regulate the Expression of ACTG2 to Control Phenotypic Switching in Human Vascular Smooth Muscle Cells During Aortic Dissection

Background Phenotypic switching in vascular smooth muscle cells (VSMCs) is involved in the pathogenesis of aortic dissection (AD). This study aims to explore the potential mechanisms of linc01278 during VSMC phenotypic switching. Methods and Results Twelve samples (6 AD and 6 control) were used for lncRNA, microRNA, and mRNA microarray analysis. We integrated the mRNA microarray data set with GSE52093 to determine the differentially expressed genes. Bioinformatic analysis, including Gene Expression Omnibus 2R, Venn diagram analysis, gene ontology, pathway enrichment, and protein-protein interaction networks were used to identify the target lncRNA, microRNA, and mRNA involved in AD. Subsequently, we validated the bioinformatics data using techniques in molecular biology in human tissues and VSMCs. Linc01278, microRNA-500b-5p, and ACTG2 played an important role in the vascular smooth muscle contraction pathway. Linc01278 and ACTG2 were downregulated and miR-500b-5p was upregulated in AD tissues. Molecular markers of VSMC phenotypic switching, including SM22α, SMA, calponin, and MYH11, were downregulated in AD tissues. Plasmid-based overexpression and RNA interference-mediated downregulation of linc01278 weakened and enhanced VSMC proliferation and phenotypic switching, respectively. Dual-luciferase reporter assays confirmed that linc01278 regulated miR-500b-5p that directly targeted ACTG2 in HEK293T cells. Conclusions These data demonstrate that linc01278 regulates ACTG2 to control the phenotypic switch in VSMCs by sponging miR-500b-5p. This linc01278-miR-500b-5p-ACTG2 axis has a potential role in developing diagnostic markers and therapeutic targets for AD.

Hydrogen Sulfide Attenuates Aortic Remodeling in Aortic Dissection Associating with Moderated Inflammation and Oxidative Stress through a NO-Dependent Pathway

Aortic dissection (AD) is a highly lethal vascular disease characterized by separation of the constituent layers of the aortic wall. An increasing body of research indicates that inflammatory response and oxidative stress are implicated in vascular remodeling, which plays a key role in the development of AD. Hydrogen sulfide (H₂S) has been found to protect against various types of cardiovascular disease, including myocardial infarction, arthrosclerosis, and hypertension. However, research on the effect of H₂S on AD is insufficient. This study therefore elucidated the effect of H₂S on the development and progression of AD, and the potential mechanism involved. Using β-aminopropionitrile fumarate (BAPN) and angiotensin II (Ang-II)-induced AD animal models, the administration of NaHS (as H₂S donor, 56 μmol/kg body weight/day) was found to retard the development of AD. Murine VSMCs (Movas) exposed to interleukin-6 (IL-6) (20 ng/mL) to induce phenotypic switch. Histological analyses indicated that H₂S administration inhibited the accumulation of inflammatory cells in the aortic wall and the related expression of inflammatory genes. Additionally, H₂S treatment elevated aortic superoxide dismutase (SOD) activity and ablated malonaldehyde (MDA) and nitric oxide (NO) levels. In mechanistic terms, H₂S attenuated IL-6 induced a pathological VSMC phenotypical switch through NO modulation by N(G)-monomethyl-L-arginine acetate salt (L-NMMA) stimulation. H₂S inhibits AD formation by decreasing the inflammatory response, and oxidative stress, and by positively participating in vascular remodeling. These findings suggest a role for H₂S as a novel and promising therapeutic strategy to prevent AD development.

Cardiovascular Outcomes in the Acute Phase of COVID-19

The cumulative number of cases in the current global coronavirus disease 19 (COVID-19) pandemic, caused by the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has exceeded 100 million, with the number of deaths caused by the infection having exceeded 2.5 million. Recent reports from most frontline researchers have revealed that SARS-CoV-2 can also cause fatal non-respiratory conditions, such as fatal cardiovascular events. One of the important mechanisms underlying the multiple organ damage that is now known to occur during the acute phase of SARS-CoV-2 infection is impairment of vascular function associated with inhibition of angiotensin-converting enzyme 2. To manage the risk of vascular dysfunction-related complications in patients with COVID-19, it would be pivotal to clearly elucidate the precise mechanisms by which SARS-CoV-2 infects endothelial cells to cause vascular dysfunction. In this review, we summarize the current state of knowledge about the mechanisms involved in the development of vascular dysfunction in the acute phase of COVID-19.

LncRNA H19 regulates smooth muscle cell functions and participates in the development of aortic dissection through sponging miR-193b-3p

BACKGROUND

Multiple studies showed that long-chain noncoding RNA H19 (LncRNA H19) is high-expressed in human and mouse abdominal aortic aneurysms (AAAs). We speculated that it plays an important role in arterial disease, and therefore studied the role and mechanism of H19 in aortic dissection (AD).

METHODS

The expressions of related genes in human aortic smooth muscle cells (HASMCs) induced by platelet-derived growth factor BB (PDGF-BB) or in the aortic tissue of AD patients/mice were identified by Western blot and quantitative real-time polymerase chain reaction. The targeting relationship between H19 and miR-193b-3p was predicted and verified by bioinformatics analysis, dual luciferase assay, RNA pull-down assay, RNA immunoprecipitation (RIP), and Pearson correlation coefficient. The H19 and miR-193b-3p effects on the biological functions of tissues and cells were examined by MTT (3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide, thiazolyl blue tetrazolium bromide) assay, wound-healing assay, and Hematoxylin-Eosin (HE) staining.

RESULTS

LncRNA H19 was abnormally high-expressed in thoracic aorta tissues of AD patients, and it could competitively bind to and inhibit miR-193b-3p. In the PDGF-BB group, the expressions of H19, matrix metallopeptidase (MMP) 2 (MMP-2) and MMP-9 were up-regulated and the expressions of miR-193b-3p, α-SMA, and SM22α were down-regulated; moreover, the proliferation and migration rate of HASMCs were increased. However, H19 silencing reversed the regulation of PDGF-BB on HASMCs. More interestingly, miR-193b-3p inhibitor could partially reverse the effect of H19 silencing. In addition, the above results were verified by animal experiments, showing that shH19 and up-regulated miR-193b-3p could significantly reduce the thoracic aorta pathological damage in AD mice.

CONCLUSION

LncRNA H19 regulated smooth muscle cell function by sponging miR-193b-3p and it participated in the development of AD.

Bioinformatics Analysis Reveals MicroRNA-193a-3p Regulates ACTG2 to Control Phenotype Switch in Human Vascular Smooth Muscle Cells

Aortic dissection (AD) is among the most fatal cardiovascular diseases. However, the pathogenesis of AD remains poorly understood. This study aims to integrate the microRNAs (miRNA) and mRNA profiles and use bioinformatics analyses with techniques in molecular biology to delineate the potential mechanisms involved in the development of AD. We used the human miRNA and mRNA microarray datasets GSE98770, GSE52093, and GEO2R, Venn diagram analysis, gene ontology, and protein–protein interaction networks to identify target miRNAs and mRNAs involved in AD. RNA interference, western blotting, and luciferase reporter assays were performed to validate the candidate miRNAs and mRNAs in AD tissues and human vascular smooth muscle cells (VSMCs). Furthermore, we studied vascular smooth muscle contraction in AD. In silico analyses revealed that miR-193a-3p and ACTG2 were key players in the pathogenesis of AD. miR-193a-3p was upregulated in the AD tissues. We also found that biomarkers for the contractile phenotype in VSMCs were downregulated in AD tissues. Overexpression and depletion of miR-193a-3p enhanced and suppressed VSMC proliferation and migration, respectively. Dual luciferase reporter assays confirmed that ACTG2 was a target of miR-193a-3p. ACTG2 was also downregulated in human AD tissues and VMSCs overexpressing miR-193a-3p. Taken together, miR-193a-3p may be a novel regulator of phenotypic switching in VSMCs and the miR-193a-3p/ACTG2 axis may serve as a promising diagnostic biomarker and therapeutic candidate for AD.

The regulatory factors and pathological roles of autophagy-related protein 4 in diverse diseases: Recent research advances

Macroautophagy (autophagy) is an evolutionarily conserved and dynamic degradation/recycling pathway in which portions of the cytoplasm, such as dysfunctional proteins and surplus organelles, are engulfed by double-membrane bound vesicles through a lysosome-dependent process. As the only proteolytic enzyme of the core mammalian autophagy proteins, autophagy-related protein 4 (ATG4) primes newly synthesized pro-light chain 3 (LC3) to form LC3-I that attaches to phosphatidylethanolamine and delipidates LC3-PE to LC3-I for recycling. Besides autophagy, ATG4 has been shown to be involved in regulating various biological and pathological processes. The roles of ATG4 in cancer therapy, a methodology for ATG4 activity detection, and the discovery of chemical modulators have been well-reviewed. However, a comprehensive summary on how ATG4 is regulated by multiple factors and, thereby, how ATG4 influences autophagy or other pathways remains lacking. In this paper, we summarize multiple processes and molecules that regulate the activity of ATG4, such as micro-RNAs, posttranslational modifications, and small molecules. Additionally, we focus on the relationship between ATG4 and diverse diseases, including cancer, neurodegeneration, microbial infection, and other diseases. It provides insight regarding potential ATG4-targeted therapeutic opportunities, which could be beneficial for future studies and human health.

Autophagy Modulation in Lymphocytes From COVID-19 Patients: New Therapeutic Target in SARS-COV-2 Infection

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) is the novel coronavirus, causing coronavirus disease 2019 (COVID-19). During virus infection, several pro-inflammatory cytokines are produced, leading to the "cytokine storm." Among these, interleukin (IL)-6, tumor necrosis factor-α (TNF-α), and IL-1β seem to have a central role in the progression and exacerbation of the disease, leading to the recruitment of immune cells to infection sites. Autophagy is an evolutionarily conserved lysosomal degradation pathway involved in different aspects of lymphocytes functionality. The involvement of IL-6, TNF-α, and IL-1β in autophagy modulation has recently been demonstrated. Moreover, preliminary studies showed that SARS-CoV-2 could infect lymphocytes, playing a role in the modulation of autophagy. Several anti-rheumatic drugs, now proposed for the treatment of COVID-19, could modulate autophagy in lymphocytes, highlighting the therapeutic potential of targeting autophagy in SARS-CoV-2 infection.

Irisin and Autophagy: First Update

Aging and sedentary life style are considered independent risk factors for many disorders. Under these conditions, accumulation of dysfunctional and damaged cellular proteins and organelles occurs, resulting in a cellular degeneration and cell death. Autophagy is a conserved recycling pathway responsible for the degradation, then turnover of cellular proteins and organelles. This process is a part of the molecular underpinnings by which exercise promotes healthy aging and mitigate age-related pathologies. Irisin is a myokine released during physical activity and acts as a link between muscles and other tissues and organs. Its main beneficial function is the change of subcutaneous and visceral adipose tissue into brown adipose tissue, with a consequential increase in thermogenesis. Irisin modulates metabolic processes, acting on glucose homeostasis, reduces systemic inflammation, maintains the balance between resorption and bone formation, and regulates the functioning of the nervous system. Recently, some of its pleiotropic and favorable properties have been attributed to autophagy induction, posing irisin as an important regulator of autophagy by exercise. This review article proposes to bring together for the first time the "state of the art" knowledge regarding the effects of irisin and autophagy. Furthermore, treatments on relation between exercise/myokines and autophagy have been also achieved.

Tocilizumab improves oxidative stress and endothelial glycocalyx: A mechanism that may explain the effects of biological treatment on COVID-19

We investigated the effects of tocilizumab on endothelial glycocalyx, a determinant of vascular permeability, and myocardial function in rheumatoid arthritis (RA). Eighty RA patients were randomized to tocilizumab (n = 40) or conventional synthetic disease-modifying antirheumatic drugs (csDMARDs) and glucocorticoids (GC) (n = 40) for 3 months. Forty healthy subjects with similar age and sex served as controls. We measured: (a)perfused boundary region (PBR) of the sublingual arterial microvessels (increased PBR indicates reduced glycocalyx thickness), (b)pulse wave velocity (PWV), (c)global LV longitudinal strain (GLS), (d)global work index (GWI) using speckle tracking echocardiography and e)C-reactive protein (CRP), malondialdehyde (MDA) and protein carbonyls (PCs) as oxidative stress markers at baseline and post-treatment. Compared to controls, RA patients had impaired glycocalyx and myocardial deformation markers (P < 0.05). Compared with baseline, tocilizumab reduced PBR(2.14 ± 0.2 versus 1.97 ± 0.2 μm; P < 0.05) while no significant differences were observed post-csDMARDs + GC(P > 0.05). Compared with csDMARDs + GC, tocilizumab achieved a greater increase of GLS, GWI and reduction of MDA, PCs and CRP(P < 0.05). The percent improvement of glycocalyx thickness (PBR) was associated with the percent decrease of PWV, MDA, PCs and the percent improvement of GLS and GWI(P < 0.05). Tocilizumab improves endothelial function leading to a greater increase of effective myocardial work than csDMARDs + GC through a profound reduction of inflammatory burden and oxidative stress. This mechanism may explain the effects of tocilizumab on COVID-19.

Clinical trial registration

url: https://www.clinicaltrials.gov. Unique identifier: NCT03288584.

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Tocilizumab improves endothelial glycocalyx and increases effective myocardial work.

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IL-6 inhibition significantly reduces the inflammatory burden and oxidative stress.

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Tocilizumab may have favorable effects on diseases with excess IL-6 release.

Role of autophagy in aneurysm and dissection of the ascending aorta

Maintenance of physiologically balanced levels of autophagy is crucial for cellular homeostasis and in the normal vessel wall, balanced autophagy can be considered a cytoprotective mechanism that preserves endothelial function and prevents cardiovascular disease. Recent studies pointed out the importance of the modulation of the autophagic flux in the pathogenesis of aortic dissection and aneurysms of the ascending aorta. Notably, shear stress (and its receptor p62), IL-6, Rab7 and Atg5/IRE1α pathways of autophagy may be considered the novel super-selective therapeutic target for the preventive and postoperative treatment of aortic aneurysm and aortic dissection. This review intends to summarize current evidences in this field trying to enlighten new avenues for future researches.

Pro-elastogenic effects of mesenchymal stem cell derived smooth muscle cells in a 3D collagenous milieu

Intrinsically poor auto-regenerative repair of proteolytically-disrupted elastic matrix structures by resident SMCs in the wall of abdominal aortic aneurysms (AAAs) prevents growth arrest and regression of these wall expansions. Supporting their possible future use in a regenerative cell therapy for AAAs, in a prior study, we showed that bone marrow mesenchymal stem cell-derived Smooth Muscle Cells (BM-SMCs) secrete biological factors that have significant pro-elastogenic and anti-proteolytic effects on aneurysmal rat aortic SMCs (EaRASMCs) in non-contact co-cultures. We also identified one stable BM-SMC phenotype (cBM-SMC) generated by differentiating BM-MSCs on a 2D fibronectin substrate in the presence of PDGF (Platelet Derived Growth Factor) and TGF-β1 (Transforming Growth Factor-β1) that exhibited superior elastogenicity and pro-elastogenic/anti-proteolytic properties. In this study, we further investigated the ability of these cBM-SMCs to maintain these superior elastogenic properties in a 3D collagenous milieu alone and in co-culture with EaRASMC to evaluate their potential as an alternative cell source for cell therapy in AAA. Some of our key observations were higher contractility and greater amount of structurally intact elastin production in both standalone culture of cBM-SMCs as well as co-culture of cBM-SMCs with EaRASMCs as shown by VVG (Verhoeff-Van Gieson) staining and Pontamine Sky Blue labeling and lower MMP-9 protein expression in standalone culture in 3D collagenous environment. Our overall result indicates that cBM-SMCs possess the ability to provide elastogenic impetus in a 3D collagenous AAA milieu which is otherwise not conducive to elastogenesis. Therefore our study strongly suggest the utility of cBM-SMCs as a potential cell source for cell therapy to augment elastic matrix neo-assembly and fiber formation and attenuate proteolysis in a collagenous milieu that is evocative of the de-elasticized aneurysmal wall. STATEMENT OF SIGNIFICANCE: Abdominal aortic aneurysm (AAA) or ballooning of the aorta is one of the leading causes of cardiovascular disease (CVD) related death caused by significantly increased proteolytic activity in the aortic wall. Reversing pathophysiology of this condition is challenging due to intrinsically poor regeneration of elastin by aortic smooth muscle cells. Current management of AAA is limited to passive monitoring of the disease until it becomes large enough to receive surgical intervention and no drug based therapy currently exists. Cell based therapy can be a potential alternative treatment in this scenario because it provides elastogenic impetus to the aneurysmal SMCs, compensates for the dead SMCs and serves as a robust source of elastin while being delivered with minimal invasiveness. Hence this work will have significant impact in the field of tissue engineering and regenerative medicine.

Verification of hub genes in the expression profile of aortic dissection

Background

To assess the mRNA expression profile and explore the hub mRNAs and potential molecular mechanisms in the pathogenesis of human thoracic aortic dissection (TAD).

Methodology

mRNA microarray expression signatures of TAD tissues (n = 6) and non-TAD tissues (NT; n = 6) were analyzed by an Arraystar human mRNA microarray. Real-time PCR (qRT-PCR) was used to validate the results of the mRNA microarray. Bioinformatic tools, including Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway analysis, were utilized. Protein-protein interaction (PPI) networks were constructed based on data from the STRING database. Molecular Complex Detection (MCODE) and cytoHubba analyses were used to predict the strongest hub gene and pathway.

Results

The top 10 hub genes were CDK1, CDC20, CCNB2, CCNB1, MAD2L1, AURKA, C3AR1, NCAPG, CXCL12 and ASPM, which were identified from the PPI network. Module analysis revealed that TAD was associated with the cell cycle, oocyte meiosis, the p53 signaling pathway, and progesterone-mediated oocyte maturation. The qRT-PCR results showed that the expression of all hub genes was significantly increased in TAD samples (p < 0.05). Immunostaining of Ki-67 and CDK1 showed a high proliferation state and high expression in TAD, respectively.

Conclusions

CDK1 could be used as a potential diagnostic biomarker and therapeutic target of TAD.

miR-27a regulates vascular remodeling by targeting endothelial cells' apoptosis and interaction with vascular smooth muscle cells in aortic dissection

Rationale: Aortic dissection (AD) is caused by functional disorder of cells in the aortic wall, which is largely attributed to vascular remodeling. Therapeutic strategies for AD remain limited due to our incomplete understanding of the role of endothelial cells (ECs) in AD pathogenesis. This study aimed to identify the regulatory role of miR-27a in AD and provide a mechanistic basis for a non-invasive treatment of AD.

Methods: We harvested aortas from normal and AD patients to explore the expression of miR-27a. In vitro and in vivo assays were preformed to explore the biological effects of differential expression of miR-27a in ECs and its regulatory effect on AD.

Results: MiR-27a was lower in intima of AD samples than in healthy individuals. Downregulation of miR-27a in EC was due to up-regulated expression of fas-associated protein with death domain (FADD) and the activation of apoptosis pathway, which led to apoptosis of ECs. Migration of vascular smooth muscle cells was promoted by EC after downregulation of miR-27a due to enhancement of growth/differentiation factor 8 (GDF8) and repression of matrix metalloproteinase-20 (MMP20) in the co-culture system supernatants. Increase in FADD and apoptosis of ECs to induce AD was shown using mouse models of AD in which miR-27a was stably knocked-down by antagomir. Up-regulation of miR-27a by agomir led to a protective effect on AD.

Conclusion: Treatment with miR-27a activator that targets apoptosis of ECs strongly diminished occurrence of AD, providing a new strategy for this disease.

[Autophagy regulates the function of vascular smooth muscle cells in the formation and rupture of intracranial aneurysms]

Vascular smooth muscle cells (VSMC) are the main cellular component of vessel wall. The changes of VSMC functions including phenotypic transformation and apoptosis play a critical role in the pathogenesis of intracranial aneurysm (IA). Autophagy can participate in the regulation of vascular function by regulating cell function. In the initial stage of IA, the activation of autophagy can accelerate the phenotypic transformation of VSMC and inhibit VSMC apoptosis. With the progress of IA, the relationship between autophagy and apoptosis changes from antagonism to synergy or promotion, and a large number of apoptotic VSMC lead to the rupture of IA. In this review, we describe the role of autophagy regulating the function of VSMC in the occurrence, development and rupture of IA, for further understanding the pathogenesis of IA and finding molecular targets to prevent the formation and rupture of IA.

Integration of Gene Expression Profile Data to Verify Hub Genes of Patients with Stanford A Aortic Dissection

Thoracic aortic dissection (TAD) is a catastrophic disease worldwide, but the pathogenic genes and pathways are largely unclear. This study aims at integrating two gene expression profile datasets and verifying hub genes and pathways involved in TAD as well as exploring potential molecular mechanisms. We will combine our mRNAs expression profile (6 TAD tissues versus 6 non-TAD tissues) and GSE52093 downloaded from the Gene Expression Omnibus (GEO) database. The two mRNAs expression profiles contained 13 TAD aortic tissues and 11 non-TAD tissues. The two expression profile datasets were integrated and we found out coexpression of differentially expressed genes (DEGs) using bioinformatics methods. The gene ontology and pathway enrichment of DEGs were performed by DAVID and Kyoto Encyclopedia of Genes and Genomes online analyses, respectively. The protein-protein interaction networks of the DEGs were constructed according to the data from the STRING database. Cytohubber calculating result shows the top 10 hub genes with CDC20, AURKA, RFC4, MCM4, TYMS, MCM2, DLGAP5, FANCI, BIRC5, and POLE2. Module analysis revealed that TAD was associated with significant pathways including cell cycle, vascular smooth muscle contraction, and adrenergic signaling in cardiomyocytes. The qRT-PCR result showed that the expression levels of all the hub genes were significantly increased in OA samples (p < 0.05), and these candidate genes could be used as potential diagnostic biomarkers and therapeutic targets of TAD.

Differential effects of inhibition of interleukin 1 and 6 on myocardial, coronary and vascular function

BACKGROUND

Anakinra, an interleukin-1 receptor antagonist and tocilizumab, an interleukin-6 receptor blocker, are used for the treatment of rheumatoid arthritis. We investigated the differential effects of anakinra and tocilizumab on myocardial and vascular function in an atherosclerosis model of patients with rheumatoid arthritis.

METHODS

120 patients with rheumatoid arthritis were randomized to anakinra (n = 40), tocilizumab (n = 40) or prednisolone (n = 40) for 3 months. Primary outcome measure was the change of left ventricular longitudinal strain after 3 months of treatment. Additionally, we measured coronary flow reserve, flow-mediated dilatation of the brachial artery, carotid-femoral pulse wave velocity, malondialdehyde and protein carbonyls as oxidative stress markers and C-reactive protein blood levels at baseline and post-treatment.

RESULTS

At baseline, patients among the three treatment arms had similar age, sex, disease activity score and atherosclerotic risk factors. Compared with baseline, all patients had improved longitudinal strain (- 16% vs. - 17.8%), coronary flow reserve (2.56 vs. 2.9), malondialdehyde (2.0 vs. 1.5 µM/L), protein carbonyls (0.0132 vs. 0.0115 nmol/mg), and C-reactive protein post-treatment. In all patients, the percent decrease of malondialdehyde was correlated with percent increase of longitudinal strain (p < 0.001). Compared with tocilizumab and prednisolone, anakinra treatment resulted in a greater improvement of longitudinal strain (18.7% vs. 9.7% vs. 6%) and coronary flow reserve (29% vs. 13% vs. 1%), while pulse wave velocity and brachial blood pressure were improved only after tocilizumab treatment (11 ± 3 vs. 10.3 ± 2 m/s p < 0.05 for all comparisons).

CONCLUSIONS

Anakinra is associated with an improvement in cardiac function and tocilizumab with improvement in vascular function.

CLINICAL TRIAL REGISTRATION

URL: https:// http://www.clinicaltrials.gov . Unique identifier: NCT03288584.

Cytokines in aortic dissection

Aortic dissection (AD) is one of the most dangerous forms of vascular disease, characterized by endometrial rupture and intramural hematoma formation. Generally, the pathological process is complicated and closely related to the infiltration of inflammatory cells into the aortic wall and apoptosis of vascular smooth muscle cells. Currently, multiple cytokines, including interleukins, interferon, the tumor necrosis factor superfamily, colony stimulating factor, chemotactic factor, growth factor and so on, have all been demonstrated to play a critical role in AD. Additionally, studies of the link between cytokines and AD could deepen our understanding of the disease and may guide future treatment therapies; therefore, this review focuses on the role of cytokines in AD.

Increased interleukin-11 levels in thoracic aorta and plasma from patients with acute thoracic aortic dissection

BACKGROUND

Interleukin (IL) 11 is closely related to tumor and hematological system diseases. Recent studies have demonstrated that IL-11 also participates in cardiovascular diseases, including ischemia-reperfusion mediated heart injury and acute myocardial infarction. This study aimed to investigate whether IL-11 is involved in acute thoracic aortic dissection (TAD).

METHODS

Aortic tissue samples from normal donors and acute TAD patients were collected, and the expression of IL-11 in all aortic tissue was analyzed. In addition, blood samples from patients with chest pain were collected and divided into a non-AD (NAD) group and a TAD group according to the results of computed tomography angiography of the thoracic aorta. The plasma IL-11, IL-17 and interferon (IFN) γ in all blood samples were measured.

RESULTS

Compared with aortic tissue of normal controls, IL-11 was significantly increased in aortic tissue of acute TAD patients, especially in the torn section. The IL-11 was derived from aorta macrophages in TAD. In addition, the plasma IL-11, IL-17 and IFN-γ were significantly higher in acute TAD patients than in NAD patients, and the correlation analysis showed that IL-11 levels were positively correlated with levels of IFN-γ, IL-17, glucose, systolic blood pressure, diastolic blood pressure, white blood cells, C-reactive proteins and D-dimers. Binary logistic regression analyses showed that elevated IL11 in patients who may have diagnostic value of TAD, but less that D-dimer.

CONCLUSION

IL-11 was increased in thoracic aorta and plasma of TAD patients and may be a promising biomarker for diagnosis in patients with TAD.

Maintaining Elastogenicity of Mesenchymal Stem Cell-Derived Smooth Muscle Cells in Two-Dimensional Culture

Abdominal aortic aneurysms (AAAs) are localized expansions of the abdominal aorta that grow slowly to rupture. AAA growth is driven by irreversible elastic matrix breakdown in the aorta wall by chronically upregulated matrix metalloproteases (MMPs). Since adult vascular smooth muscle cells (SMCs) poorly regenerate elastic matrix, we previously explored utility of bone marrow mesenchymal stem cells and SMCs derived therefrom (BM-SMCs) for this purpose. One specific differentiated phenotype (cBM-SMCs) generated on a fibronectin substrate in presence of exogenous transforming growth factor-β and platelet-derived growth factor exhibited superior elastogenicity versus other phenotypes, and usefully provided proelastogenic and antiproteolytic stimuli to aneurysmal SMCs. Since in vivo cell therapy demands large cell inoculates, these derived SMCs must be propagated in vitro while maintaining their superior elastogenic, proelastogenic, and antiproteolytic characteristics. In this work, we thus investigated the culture conditions that must be provided to this propagation phase, which ensure that the differentiated SMCs maintain their phenotype and matrix regenerative benefits. Our results indicate that our BM-SMCs retain their phenotype in long-term culture even in the absence of differentiation growth factors and fibronectin substrate, but these conditions must be continued to be provided during postdifferentiation propagation if they are to maintain their superior elastic matrix deposition, crosslinking, and fiber formation properties. Our study, however, showed that cells propagated under these conditions exhibit higher expression of MMP-2, but favorably, no expression of elastolytic MMP-9. Hence, the study outcomes provide crucial guidelines to maintain phenotypic stability of cBM-SMCs during their propagation in two-dimensional culture before their delivery to the AAA wall for therapy.