Human serum albumin Cys34 oxidative modifications following infiltration in the carotid atherosclerotic plaque

The multi-dimensional impact of captopril modification on human serum albumin

Captopril is a thiol drug, widely used for the management of hypertension and cardiovascular diseases. Reactive thiols are found to covalently modify the cysteines of plasma proteins and affect their structure and function. Human serum albumin (HSA) is prone to undergo modification by various low molecular weight compounds, including drugs. Cysteine34 (Cys34) in HSA has a free thiol group with antioxidant properties, considered to be the most redox-sensitive amino acid in plasma. Through mass-spectrometric analysis, we demonstrate for the first time that captopril forms a disulfide adduct at Cys34 residue and increases the protease susceptibility of HSA to trypsin. As evidenced by our biophysical and electron microscopy studies, HSA undergoes structural alteration, aggregation and morphological changes when treated with different captopril concentrations. Molecular dynamics studies further revealed the regions of secondary structural changes in HSA due to disulfide adduct formation by captopril at Cys34. It also elucidated the residues involved in the noncovalent interactions with captopril. It is envisaged that structural change in HSA may influence the efficacy of drug delivery as well as its own biological function. These findings may thus provide significant insights into the field of pharmacology intriguing further investigation into the effects of long-term captopril treatment.

To explore the protective effect of gastrodin on PC12 cells against oxidative stress induced by lead acetate based on network pharmacology

Objective

Screening and predicting potential targets for gastrodin antioxidant stress based on network pharmacology methods, and exploring the effect of gastrodin on lead acetate induced oxidative stress in PC12 cells through cell experiments.

Methods

Through the Pharmaper database Predict the target of action of gastrodin. Through OMIM and GeneCards to collect oxidative stress targets from database, and intersect with drug targets to obtain drug disease intersection targets; Construct a PPI network diagram using the STRING database. Perform GO enrichment analysis and KEGG pathway enrichment analysis on intersection targets through the DAVID platform. Lead acetate (PbAc) exposure was used to establish a lead poisoning cell model, and intracellular ROS levels, ALB, AKT1, and Caspase-3 levels were measured.

Results

A total of 288 targets of gastrodin action, 638 targets related to oxidative stress, and 62 drug disease intersection targets were obtained, among which core targets such as ALB, AKT1, CASP3 may be closely related to oxidative stress. KEGG pathway analysis showed that gastrodin antioxidant stress mainly involved in lipid, cancer pathway and other signaling pathways. The results of the cell experiment showed that 50 μM is the optimal effective concentration for PbAc induced ROS production in PC12 cells. Gastrodin significantly increased the ROS content of PC12 cells treated with PbAc, Upregulation of ALB expression and downregulation of AKT1 and CASP3 expression.

Conclusions

Gastrodin may alleviate PbAc-induced ROS in PC12 cells, indicating potential protective effects against oxidative stress. Further studies are needed to confirm these findings and explore the underlying mechanisms.

Can lipid mediators and free fatty acids guide acute coronary syndrome diagnosis and treatment?

OBJECTIVE

The aim of this study was to investigate fatty acids, lipid mediator levels, and the desaturase index rates on different acute coronary syndrome types and their possible relationship with routine lipid parameters.

METHODS

The study included 81 patients with myocardial infarction (MI), 20 patients with unstable angina pectoris, and 31 healthy people. Fatty acids, CD59, lipoxin A4, 8-isoprostane, serum lipids, albumin, C-reactive protein (CRP), and high sensitive troponin levels were measured in all participants.

RESULTS

When the fatty acid groups were evaluated as a ratio of albumin, MUFA/albumin and SFA/albumin ratios were significantly higher in the MI group compared to the control group. Although CD59 and lipoxin A4 levels were higher in the control group, there was no significant differences between the groups. When lipoxin A4/CRP and CD59/CRP ratios were evaluated, the results were significantly lower than those in the control group.

CONCLUSION

Lipid mediators may be useful in treating atherosclerosis by contributing to the resolution of inflammation.

Novel insights about albumin in cardiovascular diseases: Focus on heart failure

The Human Plasma Proteome has always been the most investigated compartment in proteomics-based biomarker discovery, and is considered the largest and deepest version of the human proteome, reflecting the state of the body in health and disease. Even if efforts have been always dedicated to the refinement of proteomic approaches to investigate more deeply the plasma proteome, it should not be forgotten that also highly abundant plasma proteins, like human serum albumin (HSA), often neglected in these studies, might provide fundamental physiological functions in plasma, and should be better considered. This review summarizes the important roles of HSA in the context of cardiovascular diseases (CVD), and in particular in heart failure. Notwithstanding much attention has been historically directed toward the association of HSA levels and CVD risk, the advances in the field of mass spectrometry research allow also a better characterization of the effects of oxidative modifications that could alter not only the structure but also the function of HSA.

The Exposure to Human Breast Cancer Cells Altered 14 Post-Translational Modifications of Human Serum Albumin

Purpose

Serum albumin is in contact with practically all cells in the human body, including tumor cells in cancer patients. The purpose of this study was to explore whether cancer cells affect post-translational modifications (PTMs) of albumin.

Material and methods

Mass spectrometry was used to identify the PTMs. Purified human serum albumin was incubated with human breast cancer cells MDA-MB-231, MDA-MB-468, MCF7, or kept in water or in cell culture media. PTMs which were affected upon exposure of the albumin to cancer cells were identified. Three-dimensional analysis was performed to locate PTMs in albumin.

Results

We report here that an exposure to human breast cancer cells affected post-translational modifications (PTMs) of 14 peptides of human serum albumin (HSA). PTMs at 8 peptides were observed upon exposure of HSA to metastatic MDA-MB-231 and MDA-MB-468 breast cancer cells. PTMs at another 6 peptides were lost in MDA-MB-231 and MDA-MB-468 cells, while these 6 PTMs were observed in HSA exposed to conditionally tumorigenic MCF7 cells, or in HSA kept in water or a cell culture medium. Cancer cell altered phosphorylation, deamidation followed by methylation, acetylation, myristylation, palmitoylation, methylation, cysteine persulfide, and S-6-FMN cysteine modifications were detected in HSA. These PTMs locate predominantly in IB and IIA domains of HSA. Three-dimensional analysis showed that this region corresponds to the lipid-binding site and Sudlow's site 1.

Conclusion

Data reported here show that 14 PTMs of human serum albumin can be modified upon its exposure to human breast cancer cells.

Site-Directed Spin Labeling EPR Spectroscopy for Determination of Albumin Structural Damage and Hypoalbuminemia in Critical COVID-19

The main factors in the COVID-19 pathology, which can initiate extensive structural changes at the cellular and molecular levels, are the generation of free radicals in abnormal amounts, and oxidative stress. Under "oxidative shock" conditions, the proteins undergo various modifications that affect their function and activity, and as a result distribute malfunctioning protein derivatives in the body. Human serum albumin is a small globular protein characterized by a high overall binding capacity for neutral lipophilic and acidic dosage forms. The albumin concentration is crucial for the maintenance of plasma oncotic pressure, the transport of nutrients, amino acids, and drugs, the effectiveness of drug therapy, and the prevention of drug toxicity. Hypoalbuminemia and structural defects molecule in the protein suggest a risk of changed metabolism and increased plasma concentration of unbound drugs. Therefore, the albumin structural and functional changes accompanied by low protein levels can be a serious prerequisite for ineffective therapy, frequent complications, and high mortality in patients with SARS-CoV-2 infection. The current opinion aims the research community the application of Site-Directed Spin Labeling Electron Paramagnetic Resonance spectroscopy (SDSL-EPR) and 3-Maleimido-PROXYL radical in determining abnormalities of the albumin dynamics and protein concentrations in COVID-19 critical patients.

A network pharmacology technique used to investigate the potential mechanism of Ligustilide's effect on atherosclerosis

Ligustilide (LIG) is a major active ingredient in traditional Chinese medicines that is also found in plant rhizomes such as carrot, coriander, and others, and it has been demonstrated to have cardiovascular preventive benefits. However, the mechanisms through which LIG protects the cardiovascular and cerebrovascular systems in atherosclerosis (AS) remain unknown. This study was aimed to investigate the mechanisms of LIG in AS utilizing the network pharmacology and molecular docking, and then to validate the putative mechanism through experiments. The network pharmacological analysis indicated that a total of 55 were performed on LIG and AS intersection targets. The genes of LIG and AS intersection targets enriched in the regulation of receptor and enzyme activity, cytokines-related, and transcription factors, indicating that these targets were primarily involved in cell proliferation and migration, regulating cell differentiation and skeletal activities in the development of AS. Finally, molecular docking was used to validate the major targets of LIG and AS intersection targets. Further experiments revealed that LIG may inhibit cell migration induced by AngII by reducing calcium influx, and regulating phenotypic translation-related proteins SM-22α and OPN. The present study investigated the potential targets and signaling pathways of LIG, which provides new insight into its anti-atherosclerosis actions in terms of reducing inflammation, cell proliferation, and migration, and may constitute a novel target for the treatment of AS. PRACTICAL APPLICATIONS: LIG has been shown to have cardiovascular protective benefits, the mechanism by which it protects the cardiovascular and cerebrovascular systems in AS remains unknown. This study uses a holistic network pharmacology strategy to investigate putative treatment pathways and conducts exploratory experimentation. The findings demonstrate that LIG reduces VSMC migration in the treatment of AS, acts as an anti-inflammatory agent, and prevents excessive cell proliferation and migration. Finally, the goal of our research is to uncover the molecular mechanism of LIG's influence on AS. The findings will provide a new research avenue for LIG as well as suggestions for the study of other herbal treatments. These research results will provide a new research direction for LIG and provide guidance for the research of other herbal medicines. This work revealed the multi-component, multi-target, multi-pathway, and multi-disease mechanism of LIG.

The Influence of Coronary Artery Disease in the Development of Aortic Stenosis and the Importance of the Albumin Redox State

Calcific aortic valve and coronary artery diseases are related cardiovascular pathologies in which common processes lead to the calcification of the corresponding affected tissue. Among the mechanisms involved in calcification, the oxidative stress that drives the oxidation of sulfur-containing amino acids such ascysteines is of particular interest. However, there are important differences between calcific aortic valve disease and coronary artery disease, particularly in terms of the reactive oxygen substances and enzymes involved. To evaluate what effect coronary artery disease has on aortic valves, we analyzed valve tissue from patients with severe calcific aortic stenosis with and without coronary artery disease. Proteins and peptides with oxidized cysteines sites were quantified, leading to the identification of 16 proteins with different levels of expression between the two conditions studied, as well as differences in the redox state of the tissue. We also identified two specific sites of cysteine oxidation in albumin that have not been described previously. These results provide evidence that coronary artery disease affects valve calcification, modifying the molecular profile of aortic valve tissue. In addition, the redox proteome is also altered when these conditions coincide, notably affecting human serum albumin.

Assessment of Albumin ECM Accumulation and Inflammation as Novel In Vivo Diagnostic Targets for Multi-Target MR Imaging

Atherosclerosis is a progressive inflammatory vascular disease characterized by endothelial dysfunction and plaque burden. Extracellular matrix (ECM)-associated plasma proteins play an important role in disease development. Our magnetic resonance imaging (MRI) study investigates the feasibility of using two different molecular MRI probes for the simultaneous assessment of ECM-associated intraplaque albumin deposits caused by endothelial damage and progressive inflammation in atherosclerosis. Male apolipoprotein E-deficient (ApoE^-/-)-mice were fed a high-fat diet (HFD) for 2 or 4 months. Another ApoE^-/--group was treated with pravastatin and received a HFD for 4 months. T1- and T2*-weighted MRI was performed before and after albumin-specific MRI probe (gadofosveset) administration and a macrophage-specific contrast agent (ferumoxytol). Thereafter, laser ablation inductively coupled plasma mass spectrometry and histology were performed. With advancing atherosclerosis, albumin-based MRI signal enhancement and ferumoxytol-induced signal loss areas in T2*-weighted MRI increased. Significant correlations between contrast-to-noise-ratio (CNR) post-gadofosveset and albumin stain (R² = 0.78, p < 0.05), and signal loss areas in T2*-weighted MRI with Perls' Prussian blue stain (R² = 0.83, p < 0.05) were observed. No interference of ferumoxytol with gadofosveset enhancement was detectable. Pravastatin led to decreased inflammation and intraplaque albumin. Multi-target MRI combining ferumoxytol and gadofosveset is a promising method to improve diagnosis and treatment monitoring in atherosclerosis.

Oxidative Modifications in Advanced Atherosclerotic Plaques: A Focus on In Situ Protein Sulfhydryl Group Oxidation

Although oxidative stress has been long associated with the genesis and progression of the atherosclerotic plaque, scanty data on its in situ effects on protein sulfhydryl group modifications are available. Within the arterial wall, protein sulfhydryls and low-molecular-weight (LMW) thiols are involved in the cell regulation of both Reactive Oxygen Species (ROS) and Reactive Nitrogen Species (RNS) levels and are a target for several posttranslational oxidative modifications that take place inside the atherosclerotic plaque, probably contributing to both atherogenesis and atherosclerotic plaque progression towards complicated lesions. Advanced carotid plaques are characterized by very high intraplaque GSH levels, due to cell lysis during apoptotic and/or necrotic events, probably responsible for the altered equilibrium among protein sulfhydryls and LMW thiols. Some lines of evidence show that the prooxidant environment present in atherosclerotic tissue could modify filtered proteins also by protein-SH group oxidation, and demonstrate that particularly albumin, once filtered, represents a harmful source of homocysteine and cysteinylglycine inside the plaque. The oxidative modification of protein sulfhydryls, with particular emphasis to protein thiolation by LMW thiols and its association with atherosclerosis, is the main topic of this review.

Glutaredoxin 2 from big belly seahorse (Hippocampus abdominalis) and its potential involvement in cellular redox homeostasis and host immune responses

Glutaredoxins are oxidoreductases present in almost all living organisms. They belong to the thioredoxin superfamily and share the thioredoxin structure and catalytic motif. Glutaredoxin 2 has been identified as a mitochondrial protein in vertebrates. In this study, the sequence of Glutaredoxin 2 from Hippocampus abdominalis (HaGrx2) was analyzed by molecular, transcriptional, and functional assays. In-silico analysis revealed that HaGrx2 shows the highest homology with Hippocampus comes, while distinctly cluster with fish Grx2 orthologs. Tissue distribution analysis showed that HaGrx2 is ubiquitously expressed in all tissues tested, and the highest expression was observed in the brain and skin. Significant HaGrx2 transcript modulation was identified in blood and liver upon injecting bacterial and Pathogen Associated Molecular Patterns. The redox activity of HaGrx2 was revealed by Dehydroascorbic reduction and insulin disulfide reduction activity assays. Further, the deglutathionylation activity of 1 nM HaGrx2 was found to be equivalent to that of 0.84 nM HaGrx1. HaGrx2 exhibited antiapoptotic activity against H₂O₂-induced oxidative stress in FHM cells. Altogether, the results of this study suggest that HaGrx2 plays a role in redox homeostasis and innate immune responses in fish.

A Proteomic Study of Atherosclerotic Plaques in Men with Coronary Atherosclerosis

Background: To study the changes in protein composition of atherosclerotic plaques at different stages of their development in coronary atherosclerosis using proteomics. Methods: The object of research consisted of homogenates of atherosclerotic plaques from coronary arteries at different stages of development, obtained from 15 patients. Plaque proteins were separated by two-dimensional electrophoresis. The resultant protein spots were identified by the matrix-assisted laser desorption ionization method with peptide mass mapping. Results: Groups of differentially expressed proteins, in which the amounts of proteins differed more than twofold (p < 0.05), were identified in pools of homogenates of atherosclerotic plaques at three stages of development. The amounts of the following proteins were increased in stable atherosclerotic plaques at the stage of lipidosis and fibrosis: vimentin, tropomyosin β-chain, actin, keratin, tubulin β-chain, microfibril-associated glycoprotein 4, serum amyloid P-component, and annexin 5. In plaques at the stage of fibrosis and calcification, the amounts of mimecan and fibrinogen were increased. In unstable atherosclerotic plaque of the necrotic–dystrophic type, the amounts of human serum albumin, mimecan, fibrinogen, serum amyloid P-component and annexin were increased. Conclusion: This proteomic study identifies the proteins present in atherosclerotic plaques of coronary arteries by comparing their proteomes at three different stages of plaque development during coronary atherosclerosis.

Recombinant Human Serum Albumin Containing 3 Copies of Domain I, Has Significant in Vitro Antioxidative Capacity Compared to the Wild-Type

Human serum albumin (HSA), the most abundant protein in serum, functions as carrier of drugs and contributes to maintaining serum colloid osmotic pressure. We report herein on the preparation of a genetic recombinant HSA, in which domains II and III were changed to domain I (triple domain I; TDI). Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) results indicated that the purity of the TDI was equivalent to that of the wild type (WT). Both far- and near-UV circular dichroism (CD) spectra of the TDI showed that its structural characteristics were similar to the WT. Ligand binding capacity was examined by an ultrafiltration method using 3-carboxy-4-methyl-5-propyl-2-furanpropanoic acid (CMPF) and ketoprofen as markers for site I and site II, respectively. The binding capacity of TDI for both ligands was lower than that for the wild type. TDI significantly suppressed the oxidation of dihydrorhodamine 123 (DRD) by H₂O₂ compared to the WT. Our current results suggest that TDI has great potential for further development as HSA a product having antioxidative functions.

Profiling the Serum Albumin Cys34 Adductome of Solid Fuel Users in Xuanwei and Fuyuan, China

Xuanwei and Fuyuan counties in China have the highest lung cancer rates in the world due to household air pollution from combustion of smoky coal for cooking and heating. To discover potential biomarkers of indoor combustion products, we profiled adducts at the Cys34 locus of human serum albumin (HSA) in 29 nonsmoking Xuanwei and Fuyuan females who used smoky coal, smokeless coal, or wood and 10 local controls who used electricity or gas fuel. Our untargeted "adductomics" method detected 50 tryptic peptides of HSA, containing Cys34 and prominent post-translational modifications. Putative adducts included Cys34 oxidation products, mixed disulfides, rearrangements, and truncations. The most significant differences in adduct levels across fuel types were observed for S-glutathione (S-GSH) and S-γ-glutamylcysteine (S-γ-GluCys), both of which were present at lower levels in subjects exposed to combustion products than in controls. After adjustment for age and personal measurements of airborne benzo(a)pyrene, the largest reductions in levels of S-GSH and S-γ-GluCys relative to controls were observed for users of smoky coal, compared to users of smokeless coal and wood. These results point to possible depletion of GSH, an essential antioxidant, and its precursor γ-GluCys in nonsmoking females exposed to indoor-combustion products in Xuanwei and Fuyuan, China.

Infliximab equivalently suppresses oxidative stress compared to tocilizumab among well-controlled patients with rheumatoid arthritis

AIM

This study was designed to investigate which biological agent, infliximab or tocilizumab, would more intensively keep suppressing oxidative stress among well-controlled patients as C-reactive protein (CRP) levels normalized in rheumatoid arthritis (RA). In addition, it was intended to clarify indicative factors of oxidative stress among well-controlled patients with RA.

METHODS

We recruited 61 well-controlled (CRP < 0.3 mg/dL within normal ranges) patients with RA using biological agents (infliximab n = 33; tocilizumab n = 28), active RA patients with CRP > 1.0 mg/dL (n = 10) and healthy subjects (n = 10) and examined the fraction of oxidized albumin (oxidized-albumin [%]) as a marker of oxidative stress in addition to inflammatory measures and disease activity scores such as CRP, erythrocyte sedimentation rate (ESR), matrix metalloproteinase 3 (MMP-3), serum amyloid A (SAA), Clinical Disease Activity Index, Simplified Disease Activity Index, visual analog scale (VAS), Disease Activity Index of 28 joints (DAS28)-CRP, DAS28-ESR and renal function (creatinine clearance [CCr]).

RESULTS

Oxidized-albumin (%) was significantly elevated among active RA patients (33.83 ± 5.31%) as compared with healthy subjects (23.00 ± 2.56%). Although oxidized-albumin (%) among well-controlled RA patients also increased, there was no difference with oxidized-albumin (%) between infliximab and tocilizumab groups (26.40 ± 5.44% in infliximab; 26.62 ± 4.53% in tocilizumab). In Pearson's correlation, oxidized-albumin (%) had significant correlations with CRP, MMP-3, ESR, SAA, age, CCr, VAS, DAS28-CRP and DAS28-ESR. With those variables, multiple stepwise forward regression analysis was conducted and revealed that CCr, DAS28-ESR and CRP are the statistically significant explanatory variables on oxidized-albumin (%) among well-controlled RA patients.

CONCLUSIONS

We demonstrated that there was no difference with infliximab and tocilizumab on oxidative stress and we clarified that CCr, DAS28-ESR and CRP become indicative factors of oxidative stress among well-controlled RA patients.

Emerging risk biomarkers in cardiovascular diseases and disorders

Present review article highlights various cardiovascular risk prediction biomarkers by incorporating both traditional risk factors to be used as diagnostic markers and recent technologically generated diagnostic and therapeutic markers. This paper explains traditional biomarkers such as lipid profile, glucose, and hormone level and physiological biomarkers based on measurement of levels of important biomolecules such as serum ferritin, triglyceride to HDLp (high density lipoproteins) ratio, lipophorin-cholesterol ratio, lipid-lipophorin ratio, LDL cholesterol level, HDLp and apolipoprotein levels, lipophorins and LTPs ratio, sphingolipids, Omega-3 Index, and ST2 level. In addition, immunohistochemical, oxidative stress, inflammatory, anatomical, imaging, genetic, and therapeutic biomarkers have been explained in detail with their investigational specifications. Many of these biomarkers, alone or in combination, can play important role in prediction of risks, its types, and status of morbidity. As emerging risks are found to be affiliated with minor and microlevel factors and its diagnosis at an earlier stage could find CVD, hence, there is an urgent need of new more authentic, appropriate, and reliable diagnostic and therapeutic markers to confirm disease well in time to start the clinical aid to the patients. Present review aims to discuss new emerging biomarkers that could facilitate more authentic and fast diagnosis of CVDs, HF (heart failures), and various lipid abnormalities and disorders in the future.