Deficiency of peroxiredoxin 2 exacerbates angiotensin II-induced abdominal aortic aneurysm

Implications and progression of peroxiredoxin 2 (PRDX2) in various human diseases

Peroxiredoxin 2 (PRDX2), a characteristic 2-Cys enzyme is one of the foremost effective scavenger proteins against reactive oxygen species (ROS) and hydrogen peroxide (H2O2) defending cells against oxidative stress. Dysregulation of this antioxidant raises the quantity of ROS and oxidative stress implicated in several diseases. PRDX2 lowers the generation of ROS that takes part in controlling several signalling pathways occurring in neurons, protecting them from stress caused by oxidation and an inflammatory harm. Depending on the aetiological variables, the kind of cancer, and the stage of tumour development, PRDX2 may behave either as an onco-suppressor or a promoter. However, overexpression of PRDX2 may be linked to the development of numerous cancers, including those of the colon, cervix, breast, and prostate. PRDX2 also plays a beneficial effect in inflammatory diseases. PRDX2 being a thiol-specific peroxidase, is known to control proinflammatory reactions. The spilling of PRDX2, on the other hand, accelerates cognitive impairment following a stroke by triggering an inflammatory reflex. PRDX2 expression patterns in vascular cells tend to be crucial to its involvement in cardiovascular diseases. In vascular smooth muscle cells, if the protein tyrosine phosphatase is restricted, PRDX2 could avoid the neointimal thickening which relies on platelet derived growth factor (PDGF), a vital component of vascular remodelling. A proper PRDX2 balance is therefore crucial. The imbalance causes a number of illnesses, including cancers, inflammatory diseases, cardiovascular ailments, and neurological and neurodegenerative problems which are discussed in this review.

Aortic aneurysms: current pathogenesis and therapeutic targets

Aortic aneurysm is a chronic disease characterized by localized expansion of the aorta, including the ascending aorta, arch, descending aorta, and abdominal aorta. Although aortic aneurysms are generally asymptomatic, they can threaten human health by sudden death due to aortic rupture. Aortic aneurysms are estimated to lead to 150,000 ~ 200,000 deaths per year worldwide. Currently, there are no effective drugs to prevent the growth or rupture of aortic aneurysms; surgical repair or endovascular repair is the only option for treating this condition. The pathogenic mechanisms and therapeutic targets for aortic aneurysms have been examined over the past decade; however, there are unknown pathogenic mechanisms involved in cellular heterogeneity and plasticity, the complexity of the transforming growth factor-β signaling pathway, inflammation, cell death, intramural neovascularization, and intercellular communication. This review summarizes the latest research findings and current pathogenic mechanisms of aortic aneurysms, which may enhance our understanding of aortic aneurysms.

In Vivo Validation of Modulated Acoustic Radiation Force-Based Imaging in Murine Model of Abdominal Aortic Aneurysm Using VEGFR-2-Targeted Microbubbles

OBJECTIVES

The objective of this study is to validate the modulated acoustic radiation force (mARF)-based imaging method in the detection of abdominal aortic aneurysm (AAA) in murine models using vascular endothelial growth factor receptor 2 (VEGFR-2)-targeted microbubbles (MBs).

MATERIALS AND METHODS

The mouse AAA model was prepared using the subcutaneous angiotensin II (Ang II) infusion combined with the β-aminopropionitrile monofumarate solution dissolved in drinking water. The ultrasound imaging session was performed at 7 days, 14 days, 21 days, and 28 days after the osmotic pump implantation. For each imaging session, 10 C57BL/6 mice were implanted with Ang II-filled osmotic pumps, and 5 C57BL/6 mice received saline infusion only as the control group. Biotinylated lipid MBs conjugated to either anti-mouse VEGFR-2 antibody (targeted MBs) or isotype control antibody (control MBs) were prepared before each imaging session and were injected into mice via tail vein catheter. Two separate transducers were colocalized to image the AAA and apply ARF to translate MBs simultaneously. After each imaging session, tissue was harvested and the aortas were used for VEGFR-2 immunostaining analysis. From the collected ultrasound image data, the signal magnitude response of the adherent targeted MBs was analyzed, and a parameter, residual-to-saturation ratio ( Rres - sat ), was defined to measure the enhancement in the adherent targeted MBs signal after the cessation of ARF compared with the initial signal intensity. Statistical analysis was performed with the Welch t test and analysis of variance test.

RESULTS

The Rres - sat of abdominal aortic segments from Ang II-challenged mice was significantly higher compared with that in the saline-infused control group ( P < 0.001) at all 4 time points after osmotic pump implantation (1 week to 4 weeks). In control mice, the Rres - sat values were 2.13%, 1.85%, 3.26%, and 4.85% at 1, 2, 3, and 4 weeks postimplantation, respectively. In stark contrast, the Rres - sat values for the mice with Ang II-induced AAA lesions were 9.20%, 20.6%, 22.7%, and 31.8%, respectively. It is worth noting that there was a significant difference between the Rres - sat for Ang II-infused mice at all 4 time points ( P < 0.005), a finding not present in the saline-infused mice. Immunostaining results revealed the VEGFR-2 expression was increased in the abdominal aortic segments of Ang II-infused mice compared with the control group.

CONCLUSIONS

The mARF-based imaging technique was validated in vivo using a murine model of AAA and VEGFR-2-targeted MBs. Results in this study indicated that the mARF-based imaging technique has the ability to detect and assess AAA growth at early stages based on the signal intensity of adherent targeted MBs, which is correlated with the expression level of the desired molecular biomarker. The results may suggest, in very long term, a pathway toward eventual clinical implementation for an ultrasound molecular imaging-based approach to AAA risk assessment in asymptomatic patients.

Unbalanced Redox With Autophagy in Cardiovascular Disease

Precise redox balance is essential for the optimum health and physiological function of the human body. Furthermore, an unbalanced redox state is widely believed to be part of numerous diseases, ultimately resulting in death. In this review, we discuss the relationship between redox balance and cardiovascular disease (CVD). In various animal models, excessive oxidative stress has been associated with increased atherosclerotic plaque formation, which is linked to the inflammation status of several cell types. However, various antioxidants can defend against reactive oxidative stress, which is associated with an increased risk of CVD and mortality. The different cardiovascular effects of these antioxidants are presumably due to alterations in the multiple pathways that have been mechanistically linked to accelerated atherosclerotic plaque formation, macrophage activation, and endothelial dysfunction in animal models of CVD, as well as in in vitro cell culture systems. Autophagy is a regulated cell survival mechanism that removes dysfunctional or damaged cellular organelles and recycles the nutrients for the generation of energy. Furthermore, in response to atherogenic stress, such as the generation of reactive oxygen species, oxidized lipids, and inflammatory signaling between cells, autophagy protects against plaque formation. In this review, we characterize the broad spectrum of oxidative stress that influences CVD, summarize the role of autophagy in the content of redox balance-associated pathways in atherosclerosis, and discuss potential therapeutic approaches to target CVD by stimulating autophagy.

Experimental Bothrops atrox Envenomation: Blood Plasma Proteome Effects after Local Tissue Damage and Perspectives on Thromboinflammation

The clinical manifestations of Bothrops atrox envenoming involve local and systemic changes, among which edema requires substantial attention due to its ability to progress to compartmental syndromes and sometimes cause tissue loss and amputations. However, the impact of edema on the poisoned body’s system has not been explored. Thus, the present study aimed to explore the systemic pathological and inflammatory events that are altered by intraplantar injection of B. atrox venom in a mouse model through hematologic, lipidic, and shotgun proteomics analysis. Plasma samples collected showed a greater abundance of proteins related to complement, coagulation, lipid system, platelet and neutrophil degranulation, and pathways related to cell death and ischemic tolerance. Interestingly, some proteins, in particular, Prdx2 (peroxiredoxin 2), Hba (hemoglobin subunit alpha), and F9 (Factor IX), increased according to the amount of venom injected. Our findings support that B. atrox venom activates multiple blood systems that are involved in thromboinflammation, an observation that may have implications for the pathophysiological progression of envenomations. Furthermore, we report for the first time a potential role of Prdx2, Hba, and F9 as potential markers of the severity of edema/inflammation in mice caused by B. atrox.

Construction and analysis of competing endogenous RNA network and patterns of immune infiltration in abdominal aortic aneurysm

Background

Various studies have highlighted the role of circular RNAs (circRNAs) as critical molecular regulators in cardiovascular diseases, but its role in abdominal aortic aneurysm (AAA) is unclear. This study explores the potential molecular mechanisms of AAA based on the circRNA-microRNA (miRNA)-mRNA competing endogenous RNA (ceRNA) network and immune cell infiltration patterns.

Methods

The expression profiles of circRNAs (GSE144431) and mRNAs (GSE57691 and GSE47472) were obtained from the Gene Expression Omnibus (GEO). Then, the differentially expressed circRNAs (DEcircRNAs) and mRNAs (DEmRNAs) between AAA patients and healthy control samples, and the target miRNAs of these DEmRNAs and DEcircRNAs were identified. Based on the miRNA-DEmRNAs and miRNA-DEcircRNAs pairs, the ceRNA network was constructed. Furthermore, the proportion of the 22 immune cell types in AAA patients was assessed using cell type identification by estimating relative subsets of RNA transcripts (CIBERSORT) algorithm. The expressions of key genes and immune cell infiltration were validated using clinical specimens.

Results

A total of 214 DEmRNAs were identified in the GSE57691 and GSE47472 datasets, and 517 DEcircRNAs were identified in the GSE144431 dataset. The ceRNA network included 19 circRNAs, 36 mRNAs, and 68 miRNAs. Two key genes, PPARG and FOXO1, were identified among the hub genes of the established protein-protein interaction between mRNAs in the ceRNA network. Moreover, seven types of immune cells were differentially expressed between AAA patients and healthy control samples. Hub genes in ceRNA, such as FOXO1, HSPA8, and RAB5C, positively correlated with resting CD4 memory T cells or M1 macrophages, or both.

Conclusion

In conclusion, a ceRNA interaction axis was constructed. The composition of infiltrating immune cells was analyzed in the abdominal aorta of AAA patients and healthy control samples. This may help identify potential therapeutic targets for AAA.

Ageing- and AAA-associated differentially expressed proteins identified by proteomic analysis in mice

Background

Abdominal aortic aneurysm (AAA) is a disease of high prevalence in old age, and its incidence gradually increases with increasing age. There were few studies about differences in the circulatory system in the incidence of AAA, mainly because younger patients with AAA are fewer and more comorbid nonatherosclerotic factors.

Method

We induced AAA in ApoE^-/- male mice of different ages (10 or 24 weeks) and obtained plasma samples. After the top 14 most abundant proteins were detected, the plasma was analyzed by a proteomic study using the data-dependent acquisition (DDA) technique. The proteomic results were compared between different groups to identify age-related differentially expressed proteins (DEPs) in the circulation that contribute to AAA formation. Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and protein-protein interaction (PPI) network analyses were performed by R software. The top 10 proteins were determined with the MCC method of Cytoscape, and transcription factor (TF) prediction of the DEPs was performed with iRegulon (Cytoscape).

Results

The aortic diameter fold increase was higher in the aged group than in the youth group (p < 0.01). Overall, 92 DEPs related to age and involved in AAA formation were identified. GO analysis of the DEPs showed enrichment of the terms wounding healing, response to oxidative stress, regulation of body fluid levels, ribose phosphate metabolic process, and blood coagulation. The KEGG pathway analysis showed enrichment of the terms platelet activation, complement and coagulation cascades, glycolysis/gluconeogenesis, carbon metabolism, biosynthesis of amino acids, and ECM-receptor interaction. The top 10 proteins were Tpi1, Eno1, Prdx1, Ppia, Prdx6, Vwf, Prdx2, Fga, Fgg, and Fgb, and the predicted TFs of these proteins were Nfe2, Srf, Epas1, Tbp, and Hoxc8.

Conclusion

The identified proteins related to age and involved in AAA formation were associated with the response to oxidative stress, coagulation and platelet activation, and complement and inflammation pathways, and the TFs of these proteins might be potential targets for AAA treatments. Further experimental and biological studies are needed to elucidate the role of these age-associated and AAA-related proteins in the progression of AAA.

Biomarkers in EndoVascular Aneurysm Repair (EVAR) and Abdominal Aortic Aneurysm: Pathophysiology and Clinical Implications

Circulating biomarkers have been recently investigated among patients undergoing endovascular aortic aneurysm repair (EVAR) for abdominal aortic aneurysm (AAA). Considering the plethora of small descriptive studies reporting potential associations between biomarkers and clinical outcomes, this review aims to summarize the current literature considering both the treated disease (post EVAR) and the untreated disease (AAA before EVAR). All studies describing outcomes of tissue biomarkers in patients undergoing EVAR and in patients with AAA were included, and references were checked for additional sources. In the EVAR scenario, circulating interleukin-6 (IL-6) is a marker of inflammatory reaction which might predict postoperative morbidity; cystatin C is a promising early marker of post-procedural acute kidney injury; plasma matrix metalloproteinase-9 (MMP-9) concentration after 3 months from EVAR might help in detecting post-procedural endoleak. This review also summarizes the current gaps in knowledge and future direction of this field of research. Among markers used in patients with AAA, galectin and granzyme appear to be promising and should be carefully investigated even in the EVAR setting. Larger prospective trials are required to establish and evaluate prognostic models with highest values with these markers.

Protective effect of vasostatin-1 plasmid-like nanoparticles on aortic aneurysm and its mechanism

Vasostatin 1 (VS-1) plays an important role in the regulation of various tissue injury and repair processes, but its role in aortic aneurysm remains unclear. The plasmid-like nanoparticles containing the vasostatin-1 gene Pul-PGEA-pCas-sgVs-1 were constructed, and their guarantee, safety, hemolysis, and particle size were analyzed. Eighty-four eight-week-old male ApoE-mice were randomly divided into blank group (without any treatment), model group (Ang II aortic aneurysm model + tail injection of PBS), control group (modeling + tail injection of Pul-PGEA-pCas9), and experimental group (modeling + tail injection of Pul-PGEA-pCas-sgVs-1), with 21 rats in each group. The incidence, mortality, and maximum diameter of abdominal aortic aneurysm (AAA) and the contents of high sensitivity C-reactive protein (HS-CRP), soluble intercellular adhesion molecule-1 (ICAM-1), soluble vascular cell adhesion molecule-1 (VCAM-1), and TNF-a in serum were compared in different groups of mice. The results showed that Pul-PGEA-pCas-sgVs-1 had good biosafety and transfection ability. The maximum diameter of abdominal aorta, incidence of abdominal aortic aneurysm, mortality, and the expression levels of HS-CRP, ICAM-1, VCAM-1, and TNF-a in the experimental group were lower than those in the model group (P< 0.05). These results indicated that the plasmid-like nanoparticles Pul-PGEA-pCas-sgVs-1 can inhibit the development of aorta by down-regulating the expression of inflammatory factors, which played a good protective role on the aorta.

LncRNA HSPA7 in human atherosclerotic plaques sponges miR-223 and promotes the proinflammatory vascular smooth muscle cell transition

Although there are many genetic loci in noncoding regions associated with vascular disease, studies on long noncoding RNAs (lncRNAs) discovered from human plaques that affect atherosclerosis have been highly limited. We aimed to identify and functionally validate a lncRNA using human atherosclerotic plaques. Human aortic samples were obtained from patients who underwent aortic surgery, and tissues were classified according to atherosclerotic plaques. RNA was extracted and analyzed for differentially expressed lncRNAs in plaques. Human aortic smooth muscle cells (HASMCs) were stimulated with oxidized low-density lipoprotein (oxLDL) to evaluate the effect of the identified lncRNA on the inflammatory transition of the cells. Among 380 RNAs differentially expressed between the plaque and control tissues, lncRNA HSPA7 was selected and confirmed to show upregulated expression upon oxLDL treatment. HSPA7 knockdown inhibited the migration of HASMCs and the secretion and expression of IL-1β and IL-6; however, HSPA7 knockdown recovered the oxLDL-induced reduction in the expression of contractile markers. Although miR-223 inhibition promoted the activity of Nf-κB and the secretion of inflammatory proteins such as IL-1β and IL-6, HSPA7 knockdown diminished these effects. The effects of miR-223 inhibition and HSPA7 knockdown were also found in THP-1 cell-derived macrophages. The impact of HSPA7 on miR-223 was mediated in an AGO2-dependent manner. HSPA7 is differentially increased in human atheroma and promotes the inflammatory transition of vascular smooth muscle cells by sponging miR-223. For the first time, this study elucidated the molecular mechanism of action of HSPA7, a lncRNA of previously unknown function, in humans.

A long non-coding RNA (lncRNA) called HSPA7 promotes the development of atherosclerosis, plaque in arteries. Many atherosclerosis-related genetic loci are in noncoding regions of genome, but there has been an incomplete understanding of them. Sang-Hak Lee at Yonsei University College of Medicine, Seoul, South Korea, and co-workers set out to identify a lncRNA involved in atherosclerosis and investigate its mode of action. Comparison of aortic tissues allowed them to identify lncRNAs more abundant in atherosclerotic tissue but less in healthy tissue. Of the 380 lncRNAs identified, only HSPA7 reliably increased when aortic cells were treated with a trigger of atherosclerosis. Inhibiting HSPA7 restored normal function in vascular cells, decreasing migration and inflammation. Further investigation showed that HSPA7 blocks the activity of miR-223, a microRNA that suppresses inflammation. These results identify a potential therapeutic target for atherosclerosis.

Inflammasome-Dependent Peroxiredoxin 2 Secretion Induces the Classical Complement Pathway Activation

Peroxiredoxins (Prxs) are ubiquitously expressed peroxidases that reduce hydrogen peroxide or alkyl peroxide production in cells. Prxs are released from cells in response to various stress conditions, and they function as damage-associated molecular pattern molecules. However, the secretory mechanism of Prxs and their roles have not been elucidated. Thus, we aimed to determine whether inflammasome activation is a secretory mechanism of Prxs and subsequently identify the effect of the secreted Prxs on activation of the classical complement pathway. Using J774A.1, a murine macrophage cell line, we demonstrated that NLRP3 inflammasome activation induces Prx1, Prx2, Prx5, and Prx6 secretion in a caspase-1 dependent manner. Using HEK293T cells with a transfection system, we revealed that the release of Prx1 and Prx2 relies on gasdermin-D (GSDMD)-mediated secretion. Next, we confirmed the binding of both Prx1 and Prx2 to C1q; however, only Prx2 could induce the C1q-mediated classical complement pathway activation. Collectively, our results suggest that inflammasome activation is a secretory mechanism of Prxs and that GSDMD is a mediator of their secretion. Moreover, secreted Prx1 and Prx2 bind with C1q, but only Prx2 mediates the classical complement pathway activation.

Peroxiredoxins as Potential Targets for Cardiovascular Disease

Increased oxidative stress (OS) is considered a common etiology in the pathogenesis of cardiovascular disease (CVD). Therefore, the precise regulation of reactive oxygen species (ROS) in cardiovascular cells is essential to maintain normal physiological functions. Numerous regulators of cellular homeostasis are reportedly influenced by ROS. Hydrogen peroxide (H₂O₂), as an endogenous ROS in aerobic cells, is a toxic substance that can induce OS. However, many studies conducted over the past two decades have provided substantial evidence that H₂O₂ acts as a diffusible intracellular signaling messenger. Antioxidant enzymes, including superoxide dismutases, catalase, glutathione peroxidases, and peroxiredoxins (Prdxs), maintain the balance of ROS levels against augmentation of ROS production during the pathogenesis of CVD. Especially, Prdxs are regulatory sensors of transduced intracellular signals. The intracellular abundance of Prdxs that specifically react with H₂O₂ act as regulatory proteins. In this review, we focus on the role of Prdxs in the regulation of ROS-induced pathological changes in the development of CVD.

PRDX2 Protects Against Atherosclerosis by Regulating the Phenotype and Function of the Vascular Smooth Muscle Cell

Peroxiredoxin 2 (PRDX2), an inhibitor of reactive oxygen species (ROS), is potentially involved in the progression of atherosclerosis (AS). The aim of this study was to explore the role and mechanism of PRDX2 in AS. The expression of PRDX2 was evaluated in 14 human carotid artery tissues with or without AS. The results showed that the positive reaction of PRDX2 was observed in the carotid artery vascular smooth muscle cells (CAVSMCs). To assess the mechanism by which PRDX2 may function in AS, the CAVSMCs were transfected with pEX4-PRDX2 and si-PRDX2. The catalase, hydrogen peroxide (H₂O₂) scavenger, was used to further confirm that PRDX2-induced inhibitory effects might be mediated through reducing ROS levels. Phenotype alteration and functional testing included transcription testing, immunostaining, and expression studies. The drug of MAPK signaling pathway inhibitors SB203580, SP600125, and PD98059 was used to evaluate the underlying mechanism. In this study, we found that the protein level of PRDX2 and the level of H₂O₂ were higher in the human AS carotid artery tissues than in the normal carotid artery tissues, accompanied with the activation of MAPK signaling pathway. The up-regulation of PRDX2 in the CAVSMCs significantly decreased the expression of ROS, collagen type I (COL I), collagen type III (COL III), vascular cell adhesion molecule-1 (VCAM-1), and intercellular adhesion molecule-1 (ICAM-1) and inhibited the proliferation, migration, and transformation of the CAVSMCs. The up-regulation of PRDX2 reversed the effect of the CAVSMCs treated with tumor necrosis factor-α (TNF-α). In addition, PRDX2 down-regulation promoted the protein levels of p-p38, p-JNK, and p-ERK, which was confirmed in relevant MAPK inhibitor treatment experiments. Our results suggest a protective role of PRDX2, as a scavenger of ROS, in AS progression through inhibiting the VSMC phenotype alteration and function via MAPK signaling pathway.