Proteomic Profiling of Endothelial Cells Exposed to Mitomycin C: Key Proteins and Pathways Underlying Genotoxic Stress-Induced Endothelial Dysfunction

Mitomycin C (MMC)-induced genotoxic stress can be considered to be a novel trigger of endothelial dysfunction and atherosclerosis-a leading cause of cardiovascular morbidity and mortality worldwide. Given the increasing genotoxic load on the human organism, the decryption of the molecular pathways underlying genotoxic stress-induced endothelial dysfunction could improve our understanding of the role of genotoxic stress in atherogenesis. Here, we performed a proteomic profiling of human coronary artery endothelial cells (HCAECs) and human internal thoracic endothelial cells (HITAECs) in vitro that were exposed to MMC to identify the biochemical pathways and proteins underlying genotoxic stress-induced endothelial dysfunction. We denoted 198 and 71 unique, differentially expressed proteins (DEPs) in the MMC-treated HCAECs and HITAECs, respectively; only 4 DEPs were identified in both the HCAECs and HITAECs. In the MMC-treated HCAECs, 44.5% of the DEPs were upregulated and 55.5% of the DEPs were downregulated, while in HITAECs, these percentages were 72% and 28%, respectively. The denoted DEPs are involved in the processes of nucleotides and RNA metabolism, vesicle-mediated transport, post-translation protein modification, cell cycle control, the transport of small molecules, transcription and signal transduction. The obtained results could improve our understanding of the fundamental basis of atherogenesis and help in the justification of genotoxic stress as a risk factor for atherosclerosis.

Calciprotein Particles Induce Cellular Compartment-Specific Proteome Alterations in Human Arterial Endothelial Cells

Calciprotein particles (CPPs) are indispensable scavengers of excessive Ca2+ and PO43- ions in blood, being internalised and recycled by liver and spleen macrophages, monocytes, and endothelial cells (ECs). Here, we performed a pathway enrichment analysis of cellular compartment-specific proteomes in primary human coronary artery ECs (HCAEC) and human internal thoracic artery ECs (HITAEC) treated with primary (amorphous) or secondary (crystalline) CPPs (CPP-P and CPPs, respectively). Exposure to CPP-P and CPP-S induced notable upregulation of: (1) cytokine- and chemokine-mediated signaling, Ca2+-dependent events, and apoptosis in cytosolic and nuclear proteomes; (2) H+ and Ca2+ transmembrane transport, generation of reactive oxygen species, mitochondrial outer membrane permeabilisation, and intrinsic apoptosis in the mitochondrial proteome; (3) oxidative, calcium, and endoplasmic reticulum (ER) stress, unfolded protein binding, and apoptosis in the ER proteome. In contrast, transcription, post-transcriptional regulation, translation, cell cycle, and cell-cell adhesion pathways were underrepresented in cytosol and nuclear compartments, whilst biosynthesis of amino acids, mitochondrial translation, fatty acid oxidation, pyruvate dehydrogenase activity, and energy generation were downregulated in the mitochondrial proteome of CPP-treated ECs. Differentially expressed organelle-specific pathways were coherent in HCAEC and HITAEC and between ECs treated with CPP-P or CPP-S. Proteomic analysis of mitochondrial and nuclear lysates from CPP-treated ECs confirmed bioinformatic filtration findings.

The Role of Polymorphism in the Endothelial Homeostasis and Vitamin D Metabolism Genes in the Severity of Coronary Artery Disease

Coronary artery disease (CAD) remains one of the leading causes of cardiovascular morbidity and mortality worldwide. The maintenance of endothelial homeostasis and vitamin D metabolism play an important role in CAD pathogenesis. This study aimed to determine the association of endothelial homeostasis and vitamin D metabolism gene polymorphism with CAD severity. A total of 224 low-risk patients (SYNTAX score ≤ 31) and 36 high-risk patients (SYNTAX score > 31) were recruited for this study. The serum level of E-, L- and P-selectins; endothelin; eNOS; 25OH; and 1.25-dihydroxy vitamin D was measured using an enzyme-linked immunosorbent assay (ELISA). Polymorphic variants in SELE, SELP, SELPLG, END1, NOS3, VDR and GC were analyzed using a polymerase chain reaction (PCR). We found no differences in the serum levels of the studied markers between high- and low-risk patients. Three polymorphic variants associated with CAD severity were discovered: END1 rs3087459, END1 rs5370 and GC rs2298849 in the log-additive model. Moreover, we discovered a significantly decreased serum level of 1.25-dihydroxy vitamin D in high-risk CAD patients with the A/A-A/G genotypes of the rs2228570 polymorphism of the VDR gene, the A/A genotype of the rs7041 polymorphism of the GC gene and the A/A genotype of the rs2298849 polymorphism of the GC gene.

Extracellular vesicles stimulate smooth muscle cell migration by presenting collagen VI

The extracellular matrix (ECM) supports blood vessel architecture and functionality and undergoes active remodelling during vascular repair and atherogenesis. Vascular smooth muscle cells (VSMCs) are essential for vessel repair and, via their secretome, are able to invade from the vessel media into the intima to mediate ECM remodelling. Accumulation of fibronectin (FN) is a hallmark of early vascular repair and atherosclerosis and here we show that FN stimulates VSMCs to secrete small extracellular vesicles (sEVs) by activating the β1 integrin/FAK/Src pathway as well as Arp2/3-dependent branching of the actin cytoskeleton. Spatially, sEV were secreted via filopodia-like cellular protrusions at the leading edge of migrating cells. We found that sEVs are trapped by the ECM in vitro and colocalise with FN in symptomatic atherosclerotic plaques in vivo. Functionally, ECM-trapped sEVs induced the formation of focal adhesions (FA) with enhanced pulling forces at the cellular periphery. Proteomic and GO pathway analysis revealed that VSMC-derived sEVs display a cell adhesion signature and are specifically enriched with collagen VI. In vitro assays identified collagen VI as playing the key role in cell adhesion and invasion. Taken together our data suggests that the accumulation of FN is a key early event in vessel repair acting to promote secretion of collage VI enriched sEVs by VSMCs. These sEVs stimulate migration and invasion by triggering peripheral focal adhesion formation and actomyosin contraction to exert sufficient traction forces to enable VSMC movement within the complex vascular ECM network.

Atorvastatin Can Modulate DNA Damage Repair in Endothelial Cells Exposed to Mitomycin C

HMG-CoA reductase inhibitors (statins) are widely used in the therapy of atherosclerosis and have a number of pleiotropic effects, including DNA repair regulation. We studied the cytogenetic damage and the expression of DNA repair genes (DDB1, ERCC4, and ERCC5) in human coronary artery (HCAEC) and internal thoracic artery endothelial cells (HITAEC) in vitro exposed to mitomycin C (MMC) (positive control), MMC and atorvastatin (MMC+Atv), MMC followed by atorvastatin treatment (MMC/Atv) and 0.9% NaCl (negative control). MMC/Atv treated HCAEC were characterized by significantly decreased micronuclei (MN) frequency compared to the MMC+Atv group and increased nucleoplasmic bridges (NPBs) frequency compared to both MMC+Atv treated cells and positive control; DDB1, ERCC4, and ERCC5 genes were upregulated in MMC+Atv and MMC/Atv treated HCAEC in comparison with the positive control. MMC+Atv treated HITAEC were characterized by reduced MN frequency compared to positive control and decreased NPBs frequency in comparison with both the positive control and MMC/Atv group. Nuclear buds (NBUDs) frequency was significantly lower in MMC/Atv treated cells than in the positive control. The DDB1 gene was downregulated in the MMC+Atv group compared to the positive control, and the ERCC5 gene was upregulated in MMC/Atv group compared to both the positive control and MMC+Atv group. We propose that atorvastatin can modulate the DNA damage repair response in primary human endothelial cells exposed to MMC in a cell line- and incubation scheme-dependent manner that can be extremely important for understanding the fundamental aspects of pleoitropic action of atorvastatin and can also be used to correct the therapy of patients with atherosclerosis characterized by a high genotoxic load.

Calciprotein Particles Cause Physiologically Significant Pro-Inflammatory Response in Endothelial Cells and Systemic Circulation

Calciprotein particles (CPPs) represent an inherent mineral buffering system responsible for the scavenging of excessive Ca²⁺ and PO₄^3- ions in order to prevent extraskeletal calcification, although contributing to the development of endothelial dysfunction during the circulation in the bloodstream. Here, we performed label-free proteomic profiling to identify the functional consequences of CPP internalisation by endothelial cells (ECs) and found molecular signatures of significant disturbances in mitochondrial and lysosomal physiology, including oxidative stress, vacuolar acidification, accelerated proteolysis, Ca²⁺ cytosolic elevation, and mitochondrial outer membrane permeabilisation. Incubation of intact ECs with conditioned medium from CPP-treated ECs caused their pro-inflammatory activation manifested by vascular cell adhesion molecule 1 (VCAM1) and intercellular adhesion molecule 1 (ICAM1) upregulation and elevated release of interleukin (IL)-6, IL-8, and monocyte chemoattractant protein-1/ C-C motif ligand 2 (MCP-1/CCL2). Among the blood cells, monocytes were exclusively responsible for CPP internalisation. As compared to the co-incubation of donor blood with CPPs in the flow culture system, intravenous administration of CPPs to Wistar rats caused a considerably higher production of chemokines, indicating the major role of monocytes in CPP-triggered inflammation. Upregulation of sICAM-1 and IL-8 also suggested a notable contribution of endothelial dysfunction to systemic inflammatory response after CPP injections. Collectively, our results demonstrate the pathophysiological significance of CPPs and highlight the need for the development of anti-CPP therapies.

Immune Response and Lipid Metabolism Gene Polymorphisms Are Associated with the Risk of Obesity in Middle-Aged and Elderly Patients

More than two billion people around the world are overweight or obese. Even in apparently healthy people, obesity has a potent effect on their quality of life. Experimental data indicate the role of infectious agents in systemic inflammation, revealing a correlation between the dietary habits of people with obesity and the level of systemic inflammation mediators, serum lipid concentration, and hormonal and immune status. This study aimed to determine the association of immune response and lipid metabolism gene polymorphisms with the risk of obesity. This study included 560 Caucasian participants living in Western Siberia (Russian Federation). A total of 52 polymorphic sites in 20 genes were analyzed using the 5′ TaqMan nuclease assay. Four risk-associated polymorphic variants were discovered—two variants in immune response genes (IL6R rs2229238, OR = 1.92, 95% CI = 1.36–2.7, p = 0.0002 in the dominant model; IL18 rs1946518, OR = 1.45, 95% CI = 1.03–2.04, p = 0.033 in the over-dominant model) and two variants in lipid metabolism genes (LPA rs10455872, OR = 1.86, 95% CI = 1.07–3.21, p = 0.026 in the log-additive model; LEPR rs1137100, OR = 2.88, 95% CI = 1.52–5.46, p = 0.001 in the recessive model). Thus, polymorphisms in immune response and lipid metabolism genes are potentially associated with the modification of obesity risk in the Caucasian population.

P4416Influence of rosuvastatin on the secretion of leptin and its receptor by adipocytes isolated from different adipose depots in patients with ischemic heart disease

Purpose

The study was to evaluate the effect of rosuvastatin on the secretion of leptin and its receptor by adipocytes of different localization, as well as on the expression of their genes in patients with ischemic heart disease.

Methods

29 patients with coronary heart disease which will be held coronary bypass surgery. Adipocytes were isolated from the samples of SAT, EAT and PVAT obtained during coronary artery bypass grafting, which were cultured for 24 hours with rosuvastatin 1 μmol/l and 5 μmol/l. A day later, the concentration of leptin and the leptin receptor in cell culture was determined. All study was carried out in compliance with the Helsinki Declaration, and its protocol was approved by the Ethical Committee of Research Institute. Statistical analysis was performed using Statistica 10.0. All patients gave written informed consent to participate in the study.

Results

1 μmol/l of rosuvastatin increased the level of leptin 1.6 and 2.9 times higher in adipocytes SAT compared with EAT and PVAT, respectively, and 1.8 times higher in EAT than in PVAT, which is consistent with the results of expression leptin gene. The concentration of rosuvastatin 5 μmol/l had an effect only on adipocytes SAT, increasing the level of leptin 1.6 and 2.2 times in comparison with adipocytes EAT and PVAT. Rosuvastatin had no significant effect on leptin receptor soluble levels. The free leptin index was higher in adipocytes SAT in the presence of 1 μmol/l of rosuvastatin 1.6 and 2.8 times in comparison with adipocytes of EAT and PVAT.

Conclusion

The concentration of rosuvastatin 1 μmol/l had a more pronounced effect on adipocytes compared to a concentration of 5 μmol/l and increased the level of leptin and its expression in cell culture. At the same time, a high content of leptin under conditions of low expression of a soluble receptor to leptin in the presence of rosuvastatin 1 μmol/l can lead to leptin resistance, more pronounced in SAT adipocytes.

P3482Leptin, receptor to leptin and expression in adipocytes isolated from different adipose depots in patients with ischemic heart disease

Purpose

To study the peculiarities of the content of leptin and the leptin receptor in adipocyte culture of subcutaneous (SAT), epicardial (EAT) and perivascular (PVAT) adipose tissue and the expression of their genes.

Methods

29 patients with coronary heart disease were examined. Adipocytes were isolated from SAT, EAT and PVAT samples obtained during coronary artery bypass grafting, followed by evaluation (after 24 hours) of the leptin concentration (Human resistin ELISA, R&D Systems, USA) and leptin gene expression in cell culture. Magnetic resonance imaging (MRI) was used to determine the area of the visceral (VAT) and subcutaneous adipose tissue (SAT) of the abdominal region, the thickness of epicardial adipose tissue (EAT). The calculation of the free leptin index (FLI) was determined by the formula: leptin/SOB-R * 100. Leptin resistance was defined as an FLI >0.25. All study was carried out in compliance with the Helsinki Declaration, and its protocol was approved by the Ethical Committee of Research Institute. Statistical analysis was performed using Statistica 10.0.

Results

In adipocytes of EAT, leptin secretion was 1.2 times higher than in adipocytes of PVAT, which is consistent with the expression of the leptin gene. The content of leptin soluble receptor was opposite in the adipocytes of PVAT higher than in EAT and SAT 2.3 and 3.1 times, respectively. At the same time, the index of free leptin was higher in SAT adipocytes 1.3 and 3.2 times in comparison with EAT and PVAT. The correlation analysis confirmed the relationship between EAT thickness and the serum concentrations of leptin. Thus, in patients with VO, the leptin concentration had a negative dependence on the thickness of the left and right ventricle (r=−0.28, p=0.02; r=−0.33, p=0.02, respectively). A negative dependence on the EAT thickness was also established for the FLI (r=−0.28; p=0.03). PVAT of the abdominal aorta is similar to the properties of visceral AT. An analysis of the possible relationship between perivascular adipocytes and adipokine exchange rates showed a direct relationship between the volume PVAT of the abdominal aortic ventricle and leptin (r=0.44, p=0.01), as well as the FLI (r=0.56; p=0.03).

Conclusion

Adipocytes SAT, EAT and PVAT differed in the level of secretion of leptin. In epicardial and, to a greater extent, in perivascular adipocytes, a protective mechanism against a high concentration of leptin was observed due to increased secretion of the soluble receptor to leptin. The high content of leptin and the low soluble receptor for leptin led to the development of leptin resistance, which was more pronounced in the culture of adipocytes SAT. Meanwhile, the EAT thickness was inversely related to the concentration of leptin and the FLI index (one of the main leptin-resistance markers).

Adipocytes Directly Affect Coronary Artery Disease Pathogenesis via Induction of Adipokine and Cytokine Imbalances

This study aimed to investigate the adipokine and cytokine profiles of adipocytes from epicardial and subcutaneous adipose tissues in interconnection with the visceral adipose tissue area and the biochemical and clinical characteristics of patients with coronary artery disease. We assessed 84 patients with coronary artery disease (65 men, 19 women) and divided them into two groups based on the presence of visceral obesity. We sampled epicardial and subcutaneous adipose tissues from the patients with visceral obesity. We then cultured the adipocytes and evaluated their adipokine profiles and pro-inflammatory activity. Results show that the mRNA expression of adiponectin in cultures of epicardial adipocytes from patients with and without visceral obesity was lower than that in subcutaneous adipocytes. Moreover, adiponectin mRNA expression in cultures of subcutaneous and epicardial adipocytes from patients with visceral obesity was lower than that in patients without obesity. For leptin, the reverse pattern was observed, with expression higher in cultures of epicardial adipocytes than in subcutaneous adipocytes and higher in epicardial adipocytes from patients with visceral obesity than in those from subjects without visceral obesity. In addition, in epicardial adipocytes, increased expression of proinflammatory cytokine genes (IL6, TNF) was observed compared with that in subcutaneous adipocytes. In contrast, expression of IL10 was higher in cultures of subcutaneous adipocytes than in epicardial adipocytes. The epicardial adipose tissue area was associated with the presence of higher levels of leptin and TNF-α within adipocytes and serum, increased lipid and carbohydrate metabolism. Coronary artery disease, in the context of the status of epicardial adipocytes, can be characterized as “metabolic inflammation,” suggesting the direct involvement of adipocytes in pathogenesis through the development of adipokine imbalances and activation of proinflammatory processes.

Lymphocytes with multiple chromosomal damages in a large cohort of West Siberia residents: Results of long-term monitoring

Cells with specific multiple chromosome aberrations, defined as rogue cells (RC) have been described in different populations, predominantly those exposed to radiation. The frequency, etiology and related health risks have still not been elucidated due to their low frequency of occurrences and rarely performed studies. This study reports RC frequency using chromosome aberration (CA) assay in peripheral lymphocytes in the group of 3242 subjects, during a 30-year long follow-up study in a general rural and urban population, children environmentally exposed to radon, occupationally exposed population and lung cancer patients from the Kemerovo region (Siberia, Russian Federation). Results show that the highest RC frequency was present in children environmentally exposed to radon and the lowest in the general urban population. Total frequency of CA did not correlate with frequency of RC. Genotoxic analysis of air and water samples excluded anthropogenic pollution as a possible cause of genome damage and RC frequency. In 85% of RCs, double minutes, observed in a large number of human tumors, were present. Results of CA analysis suggested that radon and its decay products (alpha-emitters) were the leading factors causing RC in subjects exposed to high LET radiation. Thus, RC may be a candidate biomarker for exposure to this type of radiation.