Replication of Newly Identified Genetic Associations Between Abdominal Aortic Aneurysm and SMYD2, LINC00540, PCIF1/MMP9/ZNF335, and ERG

Olfactory Receptors and Aortic Aneurysm: Review of Disease Pathways

Aortic aneurysm, the pathological dilatation of the aorta at distinct locations, can be attributed to many different genetic and environmental factors. The resulting pathobiological disturbances generate a complex interplay of processes affecting cells and extracellular molecules of the tunica interna, media and externa. In short, aortic aneurysm can affect processes involving the extracellular matrix, lipid trafficking/atherosclerosis, vascular smooth muscle cells, inflammation, platelets and intraluminal thrombus formation, as well as various endothelial functions. Many of these processes are interconnected, potentiating one another. Newer discoveries, including the involvement of odorant olfactory receptors in these processes, have further shed light on disease initiation and pathology. Olfactory receptors are a varied group of G protein coupled-receptors responsible for the recognition of chemosensory information. Although they comprise many different subgroups, some of which are not well-characterized or identified in humans, odorant olfactory receptors, in particular, are most commonly associated with recognition of olfactory information. They can also be ectopically localized and thus carry out additional functions relevant to the tissue in which they are identified. It is thus the purpose of this narrative review to summarize and present pathobiological processes relevant to the initiation and propagation of aortic aneurysm, while also incorporating evidence associating these ectopically functioning odorant olfactory receptors with the overall pathology.

Machine Learning and Omics Analysis in Aortic Aneurysm

Aortic aneurysm is a life-threatening condition and mechanisms underlying its formation and progression are still incompletely understood. Omics approach has brought new insights to identify a broad spectrum of biomarkers and better understand cellular and molecular pathways involved. Omics generate a large amount of data and several studies have highlighted that artificial intelligence (AI) and techniques such as machine learning (ML)/deep learning (DL) can be of use in analyzing such complex datasets. However, only a few studies have so far reported the use of ML/DL for omics analysis in aortic aneurysms. The aim of this study is to summarize recent advances on the use of ML/DL for omics analysis to decipher aortic aneurysm pathophysiology and develop patient-tailored risk prediction models. In the light of current knowledge, we discuss current limits and highlight future directions in the field.

Factors associated with all-cause mortality following endovascular abdominal aortic aneurysm repair

Background: Knowledge of factors that influence all-cause mortality after endovascular abdominal aortic aneurysm repair (EVAR) could improve therapeutic strategies post-EVAR and thus patient prognosis. Our study aimed to evaluate the association between sociodemographic information, comorbidities, laboratory parameters, treatment, selected anatomical and genetic factors and all-cause mortality post-EVAR. Patients and methods: We reviewed all patients who had undergone elective EVAR for non-ruptured abdominal aortic aneurysm (AAA) between January 2010 and December 2019. AAA size (maximum diameter and volume) was measured using CT-angiography. Sac expansion was defined as at least 5 mm increase, sac regression as at least 5 mm decrease in the sac diameter determined at 36±3 months post-EVAR in relation to pre-EVAR AAA diameter. Adjustments were performed for age, hypertension, diabetes mellitus, dyslipidaemia, sex, smoking, number of lumbar arteries, patency of inferior mesenteric artery and number of reinterventions post-EVAR. Results: One hundred and sixty-two patients (150 men, 12 women) with a mean age of 72.6±7.3 years were included in the analysis. Pre-EVAR AAA diameter (HR 1.07; 95% CI 1.03 - 1.12; p=0.001), pre-EVAR AAA volume (HR 1.01; 95% CI 1.002 - 1.011; p=0.008), post-EVAR sac diameter (HR 1.06; 95% CI 1.03 - 1.10; p=0.000), post-EVAR sac volume (HR 1.01; 95% CI 1.002 - 1.011; p=0.006) and anticoagulation therapy (HR 2.46; 95% CI 1.18 - 5.14; p=0.019) were associated with higher mortality in multivariate analysis. Sac regression (HR 0.42; 95% CI 0.22 - 0.82; p=0.011), and treatment with angiotensin-converting enzyme (ACE) inhibitors or angiotensin II receptor blockers (ARBs) (HR 0.71; 95% CI 0.36 - 0.97; p=0.047) were associated with lower mortality. Conclusions: Greater pre- and post-EVAR diameter and volume, failure of sac regression and anticoagulation were associated with higher mortality post-EVAR. Reduced mortality was observed in patients treated with ACE inhibitors or ARBs, and in patients with AAA sac regression.

The many faces of the zinc finger protein 335 in brain development and immune system

Zinc finger protein 335 (ZNF335) plays a crucial role in the methylation and, consequently, regulates the expression of a specific set of genes. Variants of the ZNF335 gene have been identified as risk factors for microcephaly in a variety of populations worldwide. Meanwhile, ZNF335 has also been identified as an essential regulator of T-cell development. However, an in-depth understanding of the role of ZNF335 in brain development and T cell maturation is still lacking. In this review, we summarize current knowledge of the molecular mechanisms underlying the involvement of ZNF335 in neuronal and T cell development across a wide range of pre-clinical, post-mortem, ex vivo, in vivo, and clinical studies. We also review the current limitations regarding the study of the pathophysiological functions of ZNF335. Finally, we hypothesize a potential role for ZNF335 in brain disorders and discuss the rationale of targeting ZNF335 as a therapeutic strategy for preventing brain disorders.

Comparison of Genes Associated with Thoracic and Abdominal Aortic Aneurysms

Aneurysms impacting the ascending thoracic aorta and the abdominal aorta affect patient populations with distinct clinical characteristics. Through a literature review, this paper compares the genetic associations of ascending thoracic aortic aneurysm (ATAA) with abdominal aortic aneurysms (AAA). Genes related to atherosclerosis, lipid metabolism, and tumor development are associated specifically with sporadic AAA, while genes controlling extracellular matrix (ECM) structure, ECM remodeling, and tumor growth factor β function are associated with both AAA and ATAA. Contractile element genes uniquely predispose to ATAA. Aside from known syndromic connective tissue disease and poly-aneurysmal syndromes (Marfan disease, Loeys-Dietz syndrome, and Ehlers-Danlos syndrome), there is only limited genetic overlap between AAA and ATAA. The rapid advances in genotyping and bioinformatics will elucidate further the various pathways associated with the development of aneurysms affecting various parts of the aorta.

Identification of PTPN22 as a potential genetic biomarker for abdominal aortic aneurysm

Abdominal aortic aneurysm (AAA) is a severe life-threatening disease that is generally asymptomatic and is diagnosed at a very late stage. The genetic component underpinning AAA is considerable, with an estimated heritability of up to 70%. Therefore, identifying genetic biomarkers for AAA is valuable for predicting high-risk populations. We used integrative bioinformatics and cellular AAA model-based validation to reveal that the gene encoding protein tyrosine phosphatase non-receptor type 22 (PTPN22) may be a potentially useful diagnostic biomarker for AAA. Integrative bioinformatics analyses of clinical specimens showed that PTPN22 expression was consistently upregulated in aortic tissues and peripheral blood mononuclear cells (PBMCs) derived from patients with AAA. Moreover, transcriptomics data revealed that PTPN22 is a potential biomarker for AAA with limited diagnostic value in patients with thoracic aortic aneurysm/dissection. Single-cell RNA sequencing-based findings further highlight PTPN22 expression in aortic immune cells and vascular smooth muscle cells (VSMCs) is consistently upregulated in patients with AAA. A cellular AAA model was eventually employed to verify the increase in PTPN22 expression. Collectively, the results indicate that PTPN22 could be a potentially useful diagnostic biomarker for AAA.

Functions of SMYD proteins in biological processes: What do we know? An updated review

BACKGROUND

Epigenetic modifiers, such as methyltransferases, play crucial roles in the regulation of many biological processes, including development, cancer and multiple physiopathological conditions.

SUMMARY

The Su(Var)3-9, Enhancer-of-zeste and Trithorax (SET) and Myeloid, Nervy, and DEAF-1 (MYND) domain-containing (SMYD) protein family consists of five members in humans and mice (i.e. SMYD1, SMYD2, SMYD3, SMYD4 and SMYD5), which are known or predicted to have methyltransferase activity on histone and non-histone substrates. The abundance of information concerning SMYD2 and SMYD3 is of note, whereas the other members of the SMYD family have not been so thoroughly studied CONCLUSION: Here we review the literature regarding SMYD proteins published in the last five years, including basic molecular biology mechanistic studies using in vitro systems and animal models, as well as human studies with a more translational or clinical approach.

Smoking, Hypertension, and GG Genotype of the IL-6 rs1800796 Polymorphism are Independent Risk Factors for Abdominal Aortic Aneurysm in Han Population

Background

Recent researches have investigated the link between the rs1800796 polymorphism (−572G/C) in the interleukin-6 (IL-6) gene and the risk of abdominal aortic aneurysm (AAA). However, no Chinese studies have addressed the association between the risk of AAA and this polymorphism.

Methods

This case-control study included 153 AAA patients and 205 controls. Diabetes mellitus, hypertension, dyslipidemia, and coronary artery disease (CAD) status were collected. The AAA and control groups were 69.20 ± 7.56 and 68.50 ± 7.12 years old, respectively.

Results

The analysis revealed that the G allele and GG genotype of the IL-6 rs1800796 polymorphism were remarkedly correlated with an elevated risk of AAA. The GG genotype displayed an association with the risk of AAA after adjustment for gender, body mass index, age, drinking, and smoking. Subgroup analyses indicated that this polymorphism elevated the risk of AAA among males, individuals aged ≥70 years, smokers, drinkers, individuals with a body mass index (BMI) ≥25 kg/m², patients without diabetes, and patients with hypertension. Univariate and multivariate analyses indicated that smoking, hypertension, and the GG genotype (rs1800796 polymorphism) were independently related with the risk of AAA.

Conclusion

The IL-6 rs1800796 polymorphism increases the risk of AAA. In addition, smoking, hypertension, and the GG genotype of the rs1800796 polymorphism are independent risk factors for AAA. Further studies of Chinese populations are needed to validate these findings.

Circular RNA Expression: Its Potential Regulation and Function in Abdominal Aortic Aneurysms

Abdominal aortic aneurysms (AAAs) have posed a great threat to human life, and the necessity of its monitoring and treatment is decided by symptomatology and/or the aneurysm size. Accumulating evidence suggests that circular RNAs (circRNAs) contribute a part to the pathogenesis of AAAs. circRNAs are novel single-stranded RNAs with a closed loop structure and high stability, having become the candidate biomarkers for numerous kinds of human disorders. Besides, circRNAs act as molecular "sponge" in organisms, capable of regulating the transcription level. Here, we characterize that the molecular mechanisms underlying the role of circRNAs in AAA development were further elucidated. In the present work, studies on the biosynthesis, bibliometrics, and mechanisms of action of circRNAs were aims comprehensively reviewed, the role of circRNAs in the AAA pathogenic mechanism was illustrated, and their potential in diagnosing AAAs was examined. Moreover, the current evidence about the effects of circRNAs on AAA development through modulating endothelial cells (ECs), macrophages, and vascular smooth muscle cells (VSMCs) was summarized. Through thorough investigation, the molecular mechanisms underlying the role of circRNAs in AAA development were further elucidated. The results demonstrated that circRNAs had the application potential in the diagnosis and prevention of AAAs in clinical practice. The study of circRNA regulatory pathways would be of great assistance to the etiologic research of AAAs.

Systematic review of genome-wide association studies of abdominal aortic aneurysm

BACKGROUND AND AIMS

Abdominal aortic aneurysm (AAA) is an important cause of death worldwide and has an estimated heritability between 70 and 77%. Genome-wide association studies (GWAS) are an established way to discover genetic risk variants. The aim of this study was to systematically review the findings and quality of previous AAA GWAS.

METHODS

The Medline, PubMed, Web of Science and relevant genetic databases were searched to identify previous AAA GWAS. A framework was developed to grade the methodological quality of the GWAS. Data from included studies were extracted to assess methods and findings.

RESULTS

Eight case-control studies were included. Thirty-three of the 38 total single nucleotide polymorphisms (SNPs) previously reported were associated with AAA diagnosis at genome-wide significance (p < 5.0 × 10^-8). The CDKN2B antisense RNA-1 gene had the most significant association with AAA diagnosis (p = 6.94 × 10^-29 and p = 1.54 × 10^-33 for rs4007642 and rs10757274 respectively). Age, sex and smoking history were not reported for the complete cohort in any of the included studies, although five of the eight studies adjusted or matched for at least two confounding variables. All included studies had important design limitations including lack of sample size estimation, inconsistent case and control ascertainment and limited phenotyping of the AAAs. AAA growth was assessed in one GWAS, however, no significant associations with the reported SNPs were found.

CONCLUSIONS

This systematic review identified 33 SNPs associated with AAA diagnosis at genome-wide significance previously validated in multiple cohorts. The association between SNPs and AAA growth was not adequately examined. Previous GWAS have a number of design limitations.

Prostate Cancer Mortality Associated with Aggregate Polymorphisms in Androgen-Regulating Genes: The Atherosclerosis Risk in the Communities (ARIC) Study

Genetic variations in androgen metabolism may influence prostate cancer (PC) prognosis. Clinical studies consistently linked PC prognosis with four single nucleotide polymorphisms (SNPs) in the critical androgen-regulating genes: 3-beta-hydroxysteroid dehydrogenase (HSD3B1) rs1047303, 5-alpha-reductase 2 (SRD5A2) rs523349, and solute carrier organic ion (SLCO2B1) rs1789693 and rs12422149. We tested the association of four androgen-regulating SNPs, individually and combined, with PC-specific mortality in the ARIC population-based prospective cohort. Men diagnosed with PC (N = 622; 79% White, 21% Black) were followed for death (N = 350) including PC death (N = 74). Cox proportional hazards regression was used to estimate hazard ratios (HR) and 95%CI adjusting for center, age, stage, and grade at diagnosis using separate hazards for races. A priori genetic risk score (GRS) was created as the unweighted sum of risk alleles in the four pre-selected SNPs. The gain-of-function rs1047303C allele was associated PC-specific mortality among men with metastatic PC at diagnosis (HR = 4.89 per risk allele, p = 0.01). Higher GRS was associated with PC-specific mortality (per risk allele: HR = 1.26, p = 0.03). We confirmed that the gain-of-function allele in HSD3B1 rs1047303 is associated with greater PC mortality in men with metastatic disease. Additionally, our findings suggest a cumulative effect of androgen-regulating genes on PC-specific mortality; however, further validation is required.