Whole-Blood Transcriptome Unveils Altered Immune Response in Acute Myocardial Infarction Patients With Aortic Valve Sclerosis.

BACKGROUND: Aortic valve sclerosis (AVSc) presents similar pathogenetic mechanisms to coronary artery disease and is associated with short- and long-term mortality in patients with coronary artery disease. Evidence of AVSc-specific pathophysiological traits in acute myocardial infarction (AMI) is currently lacking. Thus, we aimed to identify a blood-based transcriptional signature that could differentiate AVSc from no-AVSc patients during AMI. METHODS: Whole-blood transcriptome of AVSc (n=44) and no-AVSc (n=66) patients with AMI was assessed by RNA sequencing on hospital admission. Feature selection, differential expression, and enrichment analyses were performed to identify gene expression patterns discriminating AVSc from no-AVSc and infer functional associations. Multivariable Cox regression analysis was used to estimate the hazard ratios of cardiovascular events in AVSc versus no-AVSc patients. RESULTS: This cross-sectional study identified a panel of 100 informative genes capable of distinguishing AVSc from no-AVSc patients with 94% accuracy. Further analysis revealed significant mean differences in 143 genes, of which 30 genes withstood correction for age and previous AMI or coronary interventions. Functional inference unveiled a significant association between AVSc and key biological processes, including acute inflammatory responses, type I IFN (interferon) response, platelet activation, and hemostasis. Notably, patients with AMI with AVSc exhibited a significantly higher incidence of adverse cardiovascular events during a 10-year follow-up period, with a full adjusted hazard ratio of 2.4 (95% CI, 1.3-4.5). CONCLUSIONS: Our findings shed light on the molecular mechanisms underlying AVSc and provide potential prognostic insights for patients with AMI with AVSc. During AMI, patients with AVSc showed increased type I IFN (interferon) response and earlier adverse cardiovascular outcomes. Novel pharmacological therapies aiming at limiting type I IFN response during or immediately after AMI might improve poor cardiovascular outcomes of patients with AMI with AVSc.

Reduction of Cardiac Fibrosis by Interference With YAP-Dependent Transactivation.

BACKGROUND: Conversion of cardiac stromal cells into myofibroblasts is typically associated with hypoxia conditions, metabolic insults, and/or inflammation, all of which are predisposing factors to cardiac fibrosis and heart failure. We hypothesized that this conversion could be also mediated by response of these cells to mechanical cues through activation of the Hippo transcriptional pathway. The objective of the present study was to assess the role of cellular/nuclear straining forces acting in myofibroblast differentiation of cardiac stromal cells under the control of YAP (yes-associated protein) transcription factor and to validate this finding using a pharmacological agent that interferes with the interactions of the YAP/TAZ (transcriptional coactivator with PDZ-binding motif) complex with their cognate transcription factors TEADs (TEA domain transcription factors), under high-strain and profibrotic stimulation. METHODS: We employed high content imaging, 2-dimensional/3-dimensional culture, atomic force microscopy mapping, and molecular methods to prove the role of cell/nuclear straining in YAP-dependent fibrotic programming in a mouse model of ischemia-dependent cardiac fibrosis and in human-derived primitive cardiac stromal cells. We also tested treatment of cells with Verteporfin, a drug known to prevent the association of the YAP/TAZ complex with their cognate transcription factors TEADs. RESULTS: Our experiments suggested that pharmacologically targeting the YAP-dependent pathway overrides the profibrotic activation of cardiac stromal cells by mechanical cues in vitro, and that this occurs even in the presence of profibrotic signaling mediated by TGF-ß1 (transforming growth factor beta-1). In vivo administration of Verteporfin in mice with permanent cardiac ischemia reduced significantly fibrosis and morphometric remodeling but did not improve cardiac performance. CONCLUSIONS: Our study indicates that preventing molecular translation of mechanical cues in cardiac stromal cells reduces the impact of cardiac maladaptive remodeling with a positive effect on fibrosis.

Effects of RAGE Deletion on the Cardiac Transcriptome during Aging.

Cardiac aging is characterized by increased cardiomyocyte hypertrophy, myocardial stiffness, and fibrosis, which enhance cardiovascular risk. The receptor for advanced glycation end-products (RAGE) is involved in several age-related diseases. RAGE knockout (Rage-/-) mice show an acceleration of cardiac dimension changes and interstitial fibrosis with aging. This study identifies the age-associated cardiac gene expression signature induced by RAGE deletion. We analyzed the left ventricle transcriptome of 2.5-(Young), 12-(Middle age, MA), and 21-(Old) months-old female Rage-/- and C57BL/6N (WT) mice. By comparing Young, MA, and Old Rage-/- versus age-matched WT mice, we identified 122, 192, and 12 differently expressed genes, respectively. Functional inference analysis showed that RAGE deletion is associated with: (i) down-regulation of genes involved in antigen processing and presentation of exogenous antigen, adaptive immune response, and cellular responses to interferon beta and gamma in Young animals; (ii) up-regulation of genes related to fatty acid oxidation, cardiac structure remodeling and cellular response to hypoxia in MA mice; (iii) up-regulation of few genes belonging to complement activation and triglyceride biosynthetic process in Old animals. Our findings show that the age-dependent cardiac phenotype of Rage-/- mice is associated with alterations of genes related to adaptive immunity and cardiac stress pathways.

Multiomic Approaches to Uncover the Complexities of Dystrophin-Associated Cardiomyopathy.

Despite major progress in treating skeletal muscle disease associated with dystrophinopathies, cardiomyopathy is emerging as a major cause of death in people carrying dystrophin gene mutations that remain without a targeted cure even with new treatment directions and advances in modelling abilities. The reasons for the stunted progress in ameliorating dystrophin-associated cardiomyopathy (DAC) can be explained by the difficulties in detecting pathophysiological mechanisms which can also be efficiently targeted within the heart in the widest patient population. New perspectives are clearly required to effectively address the unanswered questions concerning the identification of authentic and effectual readouts of DAC occurrence and severity. A potential way forward to achieve further therapy breakthroughs lies in combining multiomic analysis with advanced preclinical precision models. This review presents the fundamental discoveries made using relevant models of DAC and how omics approaches have been incorporated to date.

GARS: Genetic Algorithm for the identification of a Robust Subset of features in high-dimensional datasets.

BACKGROUND: Feature selection is a crucial step in machine learning analysis. Currently, many feature selection approaches do not ensure satisfying results, in terms of accuracy and computational time, when the amount of data is huge, such as in 'Omics' datasets. RESULTS: Here, we propose an innovative implementation of a genetic algorithm, called GARS, for fast and accurate identification of informative features in multi-class and high-dimensional datasets. In all simulations, GARS outperformed two standard filter-based and two 'wrapper' and one embedded' selection methods, showing high classification accuracies in a reasonable computational time. CONCLUSIONS: GARS proved to be a suitable tool for performing feature selection on high-dimensional data. Therefore, GARS could be adopted when standard feature selection approaches do not provide satisfactory results or when there is a huge amount of data to be analyzed.

Genome-Wide Expression Profiling Unveils Autoimmune Response Signatures in the Perivascular Adipose Tissue of Abdominal Aortic Aneurysm.

Objective- Perivascular adipose tissue (PVAT) is thought to play a role in vascular homeostasis and in the pathogenesis of large vessel diseases, including abdominal aortic aneurysm (AAA). Herein, we tested the hypothesis that locally restricted transcriptional profiles characterize PVAT surrounding AAA, indicating specific dysfunctions associated with the disease. Approach and Results- Using a paired sample design to limit the effects of interindividual variation, we performed a microarray-based investigation of the PVAT transcriptome in 30 patients with AAA, comparing the adipose layer of the dilated abdominal aorta with that of the not-dilated aortic neck in each patient. Furthermore, we used a state-of-the-art data mining procedure to remove the effect of confounders produced by high-throughput gene expression techniques. We found substantial differences in PVAT gene expression clearly distinguishing the dilated from the not-dilated aorta, which increased in number and magnitude with increasing AAA diameter. Comparisons with other adipose depots (omental or subcutaneous fat) confirmed that gene expression changes are locally restricted. We dissected putative mechanisms associated with AAA PVAT dysfunction through a functional enrichment network analysis: both innate and adaptive immune-response genes along with genes related to cell-death pathways, metabolic processes of collagen, sphingolipids, aminoglycans, and extracellular matrix degradation were strongly overrepresented in PVAT of AAA compared with PVAT of the not-dilated aorta. Conclusions- Our results support a possible function of PVAT in AAA pathogenesis and suggest that AAA is an immunologic disease with an underlying autoimmune component. Interfering with these disease-specific pathways would clarify their precise role in AAA pathogenesis.

Melanocortin-1 Receptor Positively Regulates Human Artery Endothelial Cell Migration.

BACKGROUND/AIMS: Melanocortin receptors (MCRs) belong to a hormonal signalling pathway with multiple homeostatic and protective actions. Microvascular and umbilical vein endothelial cells (ECs) express components of the melanocortin system, including the type 1 receptor (MC1R), playing a role in modulating inflammation and vascular tone. Since ECs exhibit a remarkable heterogeneity, we investigated whether human artery ECs express any functional MCR and whether its activation affects cell migration. METHODS: We used reverse transcription real-time PCR to examine the expression of melanocortin system components in primary human artery ECs. We assessed MC1R protein expression and activity by western blot, immunohistochemistry, cAMP production, and intracellular Ca²âº mobilization assays. We performed gap closure and scratch tests to examine cell migration after stimulation with alpha-melanocyte-stimulating hormone (α-MSH), the receptor highest-affinity natural ligand. We assessed differential time-dependent transcriptional changes in migrating cells by microarray analysis. RESULTS: We showed that human aortic ECs (HAoECs) express a functionally active MC1R. Unlike microvascular ECs, arterial cells did not express the α-MSH precursor proopiomelanocortin, nor produced the hormone. MC1R engagement with a single pulse of α-MSH accelerated HAoEC migration both in the directional migration assay and in the scratch wound healing test. This was associated with an enhancement in Ca²âº signalling and inhibition of cAMP elevation. Time-course genome-wide expression analysis in HAoECs undergoing directional migration allowed identifying dynamic co-regulation of genes involved in extracellular matrix-receptor interaction, vesicle-mediated trafficking, and metal sensing - which have all well-established influences on EC motility -, without affecting the balance between pro- and anticoagulant genes. CONCLUSION: Our work broadens the knowledge on peripherally expressed MC1R. These results indicate that the receptor is constitutively expressed by arterial ECs and provide evidence of a novel homeostatic function for MC1R, whose activation may participate in preventing/healing endothelial dysfunction or denudation in macrovascular arteries.

DaMiRseq-an R/Bioconductor package for data mining of RNA-Seq data: normalization, feature selection and classification.

Summary: RNA-Seq is becoming the technique of choice for high-throughput transcriptome profiling, which, besides class comparison for differential expression, promises to be an effective and powerful tool for biomarker discovery. However, a systematic analysis of high-dimensional genomic data is a demanding task for such a purpose. DaMiRseq offers an organized, flexible and convenient framework to remove noise and bias, select the most informative features and perform accurate classification. Availability and implementation: DaMiRseq is developed for the R environment (R ≥ 3.4) and is released under GPL (≥2) License. The package runs on Windows, Linux and Macintosh operating systems and is freely available to non-commercial users at the Bioconductor open-source, open-development software project repository (https://bioconductor.org/packages/DaMiRseq/). In compliance with Bioconductor standards, the authors ensure stable package maintenance through software and documentation updates. Contact: luca.piacentini@ccfm.it. Supplementary information: Supplementary data are available at Bioinformatics online.

Deciphering Abdominal Aortic Diseases Through T-Cell Clonal Repertoire of Perivascular Adipose Tissue.

BACKGROUND: Recent studies suggest that immune-mediated inflammation of perivascular adipose tissue of abdominal aortic aneurysms (AAAs) contributes to disease development and progression. Whether the perivascular adipose tissue of AAA is characterized by a specific adaptive immune signature remains unknown. METHODS AND RESULTS: To investigate this hypothesis, we sequenced the T-cell receptor ß-chain in the perivascular adipose tissue of patients with AAA and compared it with patients with aortic occlusive disease, who share the former anatomical site of the lesion and risk factors but differ in pathogenic mechanisms. Our results demonstrate that patients with AAA have a lower repertoire diversity than those with aortic occlusive disease and significant differences in variable/joining gene segment usage. Furthermore, we identified a set of 7 public T-cell receptor ß-chain clonotypes that distinguished AAA and aortic occlusive disease with very high accuracy. We also found that the T-cell receptor ß-chain repertoire differentially characterizes small and large AAAs (aortic diameter<55 mm and ≥55 mm, respectively). CONCLUSIONS: This work supports the hypothesis that T cell-mediated immunity is fundamental in AAA pathogenesis and opens up new clinical perspectives.

Overactivation of plasmacytoid dendritic cells inhibits antiviral T-cell responses: a model for HIV immunopathogenesis.

A delicate balance between immunostimulatory and immunosuppressive signals mediated by dendritic cells (DCs) and other antigen-presenting cells (APCs) regulates the strength and efficacy of antiviral T-cell responses. HIV is a potent activator of plasmacytoid DCs (pDCs), and chronic pDC activation by HIV promotes the pathogenesis of AIDS. Cholesterol is pivotal in maintaining HIV envelope integrity and allowing HIV-cell interaction. By depleting envelope-associated cholesterol to different degrees, we generated virions with reduced ability to activate pDCs. We found that APC activation was dissociated from the induction of type I IFN-α/ß and indoleamine-2,3-dioxygenase (IDO)-mediated immunosuppression in vitro. Extensive cholesterol withdrawal, resulting in partial protein and RNA loss from the virions, rendered HIV a more powerful recall immunogen for stimulating memory CD8 T-cell responses in HIV-exposed, uninfected individuals. These enhanced responses were dependent on the inability of cholesterol-depleted HIV to induce IFN-α/ß.

High Phosphate-Induced JAK-STAT Signalling Sustains Vascular Smooth Muscle Cell Inflammation and Limits Calcification.

Vascular calcification (VC) is an age-related complication characterised by calcium-phosphate deposition in the arterial wall driven by the osteogenic transformation of vascular smooth muscle cells (VSMCs). The JAK-STAT pathway is an emerging target in inflammation. Considering the relationship between VC and inflammation, we investigated the role of JAK-STAT signalling during VSMC calcification. Human aortic smooth muscle cells (HASMCs) were cultured in high-inorganic phosphate (Pi) medium for up to 7 days; calcium deposition was determined via Alizarin staining and colorimetric assay. Inflammatory factor secretion was evaluated via ELISA and JAK-STAT members' activation using Western blot or immunohistochemistry on HASMCs or calcified aortas of Vitamin D-treated C57BL6/J mice, respectively. The JAK-STAT pathway was blocked by JAK Inhibitor I and Von Kossa staining was used for calcium deposits in murine aortic rings. During Pi-induced calcification, HASMCs released IL-6, IL-8, and MCP-1 and activated JAK1-JAK3 proteins and STAT1. Phospho-STAT1 was detected in murine calcified aortas. Blocking of the JAK-STAT cascade reduced HASMC proliferation and pro-inflammatory factor expression and release while increasing calcium deposition and osteogenic transcription factor RUNX2 expression. Consistently, JAK-STAT pathway inhibition exacerbates mouse aortic ring calcification ex vivo. Intriguingly, our results suggest an alternative link between VSMC inflammation and VC.

Genetic diversity at endoplasmic reticulum aminopeptidases is maintained by balancing selection and is associated with natural resistance to HIV-1 infection.

Human ERAP1 and ERAP2 encode two endoplasmic reticulum aminopeptidases. These enzymes trim peptides to optimal size for loading onto major histocompatibility complex class I molecules and shape the antigenic repertoire presented to CD8(+) T cells. Therefore, ERAP1 and ERAP2 may be considered potential selection targets and modulators of infection susceptibility. We resequenced two genic regions in ERAP1 and ERAP2 in three HapMap populations. In both cases, we observed high levels of nucleotide variation, an excess of intermediate-frequency alleles, and reduced population genetic differentiation. The genealogy of ERAP1 and ERAP2 haplotypes was split into two major branches with deep coalescence times. These features suggest that long-standing balancing selection has acted on these genes. Analysis of the Lys528Arg (rs30187 in ERAP1) and Asn392Lys (rs2549782 in ERAP2) variants in an Italian population of HIV-1-exposed seronegative (ESN) individuals and a larger number of Italian controls indicated that rs2549782 significantly deviates from Hardy-Weinberg equilibrium (HWE) in ESN but not in controls. Technical errors were excluded and a goodness-of-fit test indicated that a recessive model with only genetic effects adequately explains HWE deviation. The genotype distribution of rs2549782 is significantly different in the two cohorts (P = 0.004), mainly as the result of an over-representation of Lys/Lys genotypes in the ESN sample (P-value for a recessive model: 0.00097). Our data suggest that genetic diversity in ERAP1 and ERAP2 has been maintained by balancing selection and that variants in ERAP2 confer resistance to HIV-1 infection possibly via the presentation of a distinctive peptide repertoire to CD8(+) T cells.

TLR activation pathways in HIV-1-exposed seronegative individuals.

TLRs trigger innate immunity that recognizes conserved motifs of invading pathogens, resulting in cellular activation and release of inflammatory factors. The influence of TLR activation on resistance to HIV-1 infection has not been investigated in HIV-1 exposed seronegative (ESN) individuals. PBMCs isolated from heterosexually ESN individuals were stimulated with agonists specific for TLR3 (poly I:C), TLR4 (LPS), TLR7 (imiquimod), and TLR7/8 (ssRNA40). We evaluated expression of factors involved in TLR signaling cascades, production of downstream effector immune mediators, and TLR-expression in CD4+ and CD14+ cells. Results were compared with those obtained in healthy controls (HCs). ESN individuals showed: 1) comparable percentages of CD14+/TLR4+ and CD4+/TLR8+ CD14+/TLR8+ cells; 2) higher responsiveness to poly I:C, LPS, imiquimod, and ssRNA40 stimulation, associated with significantly increased production of IL-1beta, IL-6, TNF-alpha, and CCL3; 3) augmented expression of mRNA specific for other targets (CCL2, CSF3, CSF2, IL-1alpha, IL-8, IL-10, IL-12, cyclooxygenase 2) demonstrated by broader TLRs pathway expression analyses; and 4) increased MyD88/MyD88s(short) ratio, mainly following TLR7/8 stimulation. We also compared TLR-agonist-stimulated cytokine/chemokine production in CD14+ PBMCs and observed decreased IFN-beta production in ESN individuals compared with HCs upon TLR7/8-agonist stimulation. These data suggest that TLR stimulation in ESN individuals results in a more robust release of immunologic factors that can influence the induction of stronger adaptive antiviral immune responses and might represent a virus-exposure-induced innate immune protective phenotype against HIV-1.

Trained Immunity in Perivascular Adipose Tissue of Abdominal Aortic Aneurysm-A Novel Concept for a Still Elusive Disease.

Abdominal aortic aneurysm (AAA) is a chronic, life-threatening vascular disease whose only therapeutic option is a surgical repair to prevent vessel rupture. The lack of medical therapy results from an inadequate understanding of the etiopathogenesis of AAA. Many studies in animal and human models indicate a 'short-circuiting' of the regulation of the inflammatory-immune response as a major player in the AAA chronic process. In this regard, perivascular adipose tissue (PVAT) has received increasing interest because its dysfunction affects large arteries primarily through immune cell infiltration. Consistently, we have recently produced evidence that innate and adaptive immune cells present in the PVAT of AAAs contribute to sustaining a damaging inflammatory loop. However, it is still unclear how the complex crosstalk between adaptive and innate immunity can be self-sustaining. From our perspective, trained immunity may play a role in this crosstalk. Trained immunity is defined as a form of innate immune memory resulting in enhanced responsiveness to repeated triggers. Specific innate stimuli and epigenetic and metabolic reprogramming events induce and shape trained immunity in myeloid progenitor cells improving host defense, but also contributing to the progression of immune-mediated and chronic inflammatory diseases. Here we present this hypothesis with data from the literature and our observations to support it.

Whole-Blood Transcriptional Profiles Enable Early Prediction of the Presence of Coronary Atherosclerosis and High-Risk Plaque Features at Coronary CT Angiography.

Existing tools to estimate cardiovascular (CV) risk have sub-optimal predictive capacities. In this setting, non-invasive imaging techniques and omics biomarkers could improve risk-prediction models for CV events. This study aimed to identify gene expression patterns in whole blood that could differentiate patients with severe coronary atherosclerosis from subjects with a complete absence of detectable coronary artery disease and to assess associations of gene expression patterns with plaque features in coronary CT angiography (CCTA). Patients undergoing CCTA for suspected coronary artery disease (CAD) were enrolled. Coronary stenosis was quantified and CCTA plaque features were assessed. The whole-blood transcriptome was analyzed with RNA sequencing. We detected highly significant differences in the circulating transcriptome between patients with high-degree coronary stenosis (≥70%) in the CCTA and subjects with an absence of coronary plaque. Notably, regression analysis revealed expression signatures associated with the Leaman score, the segment involved score, the segment stenosis score, and plaque volume with density <150 HU at CCTA. This pilot study shows that patients with significant coronary stenosis are characterized by whole-blood transcriptome profiles that may discriminate them from patients without CAD. Furthermore, our results suggest that whole-blood transcriptional profiles may predict plaque characteristics.

Population genetics of IFIH1: ancient population structure, local selection, and implications for susceptibility to type 1 diabetes.

The human interferon induced with helicase C domain 1 (IFIH1) gene encodes a sensor of double-strand RNA involved in innate immunity against viruses, indicating that this gene is a likely target of virus-driven selective pressure. Notably, IFIH1 also plays a role in autoimmunity, as common and rare polymorphisms in this gene have been associated with type 1 diabetes (T1D). We analyzed the evolutionary history of IFIH1 in human populations. Results herein suggest that two major IFIH1 haplotype clades originated from ancestral population structure (or balancing selection) in the African continent and that local selective pressures have acted on the gene. Specifically, directional selection in Europe and Asia resulted in the spread of a common IFIH1 haplotype carrying a derived His460 allele. This variant changes a highly conserved arginine residue in the helicase domain, possibly conferring altered specificity in viral recognition. An alternative common haplotype has swept to high frequency in South Americans as a result of recent positive selection. Previous studies suggested that a portion of risk alleles for autoimmune diseases could have been maintained in humans as they conferred a selective advantage against infections. This is not the case for IFIH1, as population genetic differentiation and haplotype analyses indicated that the T1D susceptibility alleles behaved as neutral or nearly neutral polymorphisms. Our findings suggest that variants in IFIH1 confer different susceptibility to diverse viral infections and provide insight into the relationship between adaptation to past infection and predisposition to autoimmunity in modern populations.

Innate immunity in resistance to HIV infection.

Resistance to human immunodeficiency virus (HIV) infection in subjects who do not seroconvert despite multiple exposures to the virus and to the progression to AIDS in HIV‐infected individuals depends on multiple factors involving both the innate and the adaptive immune system. The contribution of natural immunity in preventing HIV infection has so far received little attention, but many recently published articles suggest a key role for Toll‐like receptors, natural killer cells, interleukin‐22, acute‐phase amyloid A protein, and APOBEC3G in conferring resistance to HIV infection. The study of these factors will shed light on HIV pathogenesis and contribute to the development of new therapeutic approaches to this elusive disease.

Digital PCR for high sensitivity viral detection in false-negative SARS-CoV-2 patients.

Patients requiring diagnostic testing for coronavirus disease 2019 (COVID-19) are routinely assessed by reverse-transcription quantitative polymerase chain reaction (RT-qPCR) amplification of Sars-CoV-2 virus RNA extracted from oro/nasopharyngeal swabs. Despite the good specificity of the assays certified for SARS-CoV-2 molecular detection, and a theoretical sensitivity of few viral gene copies per reaction, a relatively high rate of false negatives continues to be reported. This is an important challenge in the management of patients on hospital admission and for correct monitoring of the infectivity after the acute phase. In the present report, we show that the use of digital PCR, a high sensitivity method to detect low amplicon numbers, allowed us to correctly detecting infection in swab material in a significant number of false negatives. We show that the implementation of digital PCR methods in the diagnostic assessment of COVID-19 could resolve, at least in part, this timely issue.

Gene Regulatory Network Analysis of Perivascular Adipose Tissue of Abdominal Aortic Aneurysm Identifies Master Regulators of Key Pathogenetic Pathways.

The lack of medical therapy to treat abdominal aortic aneurysm (AAA) stems from our inadequate understanding of the mechanisms underlying AAA pathogenesis. To date, the only available treatment option relies on surgical intervention, which aims to prevent AAA rupture. Identifying specific regulators of pivotal pathogenetic mechanisms would allow the development of novel treatments. With this work, we sought to identify regulatory factors associated with co-expressed genes characterizing the diseased perivascular adipose tissue (PVAT) of AAA patients, which is crucially involved in AAA pathogenesis. We applied a reverse engineering approach to identify cis-regulatory elements of diseased PVAT genes, the associated transcription factors, and upstream regulators. Finally, by analyzing the topological properties of the reconstructed regulatory disease network, we prioritized putative targets for AAA interference treatment options. Overall, we identified NFKB1, SPIB, and TBP as the most relevant transcription factors, as well as MAPK1 and GSKB3 protein kinases and RXRA nuclear receptor as key upstream regulators. We showed that these factors could regulate different co-expressed gene subsets in AAA PVAT, specifically associated with both innate and antigen-driven immune response pathways. Inhibition of these factors may represent a novel option for the development of efficient immunomodulatory strategies to treat AAA.

Gene-expression profiles of abdominal perivascular adipose tissue distinguish aortic occlusive from stenotic atherosclerotic lesions and denote different pathogenetic pathways.

Perivascular adipose tissue (PVAT) helps regulate arterial homeostasis and plays a role in the pathogenesis of large vessel diseases. In this study, we investigated whether the PVAT of aortic occlusive lesions shows specific gene-expression patterns related to pathophysiology. By a genome-wide approach, we investigated the PVAT transcriptome in patients with aortoiliac occlusive disease. We compared the adipose layer surrounding the distal aorta (atherosclerotic lesion) with the proximal aorta (plaque-free segment), both within and between patients with complete aortoiliac occlusion (Oc) and low-grade aortic stenosis (St). We found that PVAT of the distal versus proximal aorta within both Oc- and St-patients lacks specific, locally restricted gene-expression patterns. Conversely, singular gene-expression profiles distinguished the PVAT between Oc- and St-patients. Functional enrichment analysis revealed that these signatures were associated with pathways related to metabolism of cholesterol, vessel tone regulation, and remodeling, including TGF-ß and SMAD signaling. We finally observed that gene-expression profiles in omental-visceral or subcutaneous fat differentiated between Oc- and St-patients, suggesting that the overall adipose component associates with a different atherosclerosis burden. Our work points out the role of PVAT and, likely, other adipose tissues play in the pathophysiological mechanisms underlying atherosclerotic disease, including the abdominal aortic occlusive forms.