Complement System Proteins Research Articles

Alternative Pathway Involvement in Protoporphyria Patients Related to Sun Exposure.

The homeostasis of tissues in a chronic disease is an essential function of the alternative pathway (AP) of the complement system (CS). However, if not controlled, it may also be detrimental to healthy cells with a consequent aggravation of symptoms. The protoporphyria (PP) is a rare chronic disease that causes phototoxicity in visible light with local skin pain and general malaise. In order to establish if there is a systemic involvement of the CS during sun exposure, we designed a non-invasive method with a serum collection in winter and summer from 19 PP and 13 controls to detect the levels of CS protein: Properdin, Factor H (FH), and C5. Moreover, the global radiation data were collected from the regional agency of environmental protection (ARPA). The results show growing values for every protein in patients with PP, compared to control, in both seasons, in particular in summer compared to winter. To reinforce the evidence, we have estimated the personal exposure of patients based on the global radiation data. The main factors of the AP increased over the season, confirming the involvement of the AP in relation to light exposure. The systemic response could justify the general malaise of patients after long light exposure and can be exploited to elucidate new therapeutic approaches.

Peculiarities of sheep pathogenesis at associative invasions of gastrointestinal tract

In the Republic of Belarus, primarily in farms with imperfect technology, parasitic diseases of sheep are widespread, including: nematodes of gastrointestinal tract, strongyloidosis, eimeriosis, monieziosis, trichocephalosis, cryptosporidiosis, etc. Study of impact of associative parasitosis of sheep on the immunobiological reactivity of animal body has recently become more and more theoretical and practical for rational use of drugs in treatment of these diseases. The purpose of research is to study peculiarities of sheep pathogenesis at associative invasions of gastrointestinal tract. The study was carried out at farm “Villia-agro”, Kobrin district, Brest region. Lambs of 2-4 months of age spontaneously infested with parasites of gastrointestinal tract have been selected. Parameters of cellular immunity were determined: number of leukocytes, monocytes, neutrophils, eosinophils, level of rosette-forming T- and B-lymphocytes and humoral immunity: circulating immune complexes, total protein, protein fractions, including proteins of C3 complement system and immunoglobulins, macro and microelements (calcium, phosphorus and iron) in blood serum. With spontaneous invasion of sheep by associations of parasites of gastrointestinal tract, the following changes have been determined: significant decrease in number of lymphocytes, T-lymphocytes, concentration of total protein, albumin, - β- and g-globulins, calcium and phosphorus. Significant increase in leukocytes: Eosinophils and stab neutrophils, a1-globulins , circulating immune complexes. All this together indicates disturbance in functioning of body’s immunity and requires immediate appropriate treatment aimed both at destroying associations of parasites of gastrointestinal tract and restoring immune system of animal’s body. These studies will form basis for development of rational system for therapeutic and preventive measures for associative parasitosis of sheep in the Republic of Belarus, which will reduce economic damage from these diseases and improve quality of livestock products.

Comparative Analysis of the Transcriptome, Proteome, and miRNA Profile of Kupffer Cells and Monocytes.

Macrophage populations in most mammalian organs consist of cells of different origin. Resident macrophages originate from erythromyeloid precursors of the yolk sac wall; maintenance of the numbers of such macrophages in postnatal ontogenesis is practically independent of bone marrow haematopoiesis. The largest populations of the resident macrophages of embryonic origin are found in the central nervous system (microglia) and liver (Kupffer cells). In contrast, skin dermis and mucous membranes become predominantly colonized by bone marrow-derived monocytes that show pronounced functional and phenotypic plasticity. In the present study, we compared Kupffer cells and monocytes using the immunophenotype, gene expression profile, proteome, and pool of microRNA. The observed differences did not consider the resident liver macrophages as purely M2 macrophages or state that monocytes have purely M1 features. Monocytes show signs of high plasticity and sensitivity to pathogen-associated molecular patterns (e.g., high levels of transcription for Tlr 2, 4, 7, and 8). In contrast, the resident liver macrophages were clearly involved in the regulation of specific organ functions (nitrogen metabolism, complement system protein synthesis).

Parameters of macrophage reaction and humoral immunity in patients with implant-associated in-flammation after primary endoprosthetics of knee joint

Aim. To study peculiarities of macrophage reaction and humoral immunity in patients with signs of implant-associated inflammation after the primary endoprosthetics of the knee joint.
 Materials and Methods. Examination of 48 patients with signs of implant-associated inflammation after the primary endoprosthetics of the knee joints (the main group) and of 44 patients without signs of inflammatory reactions (comparison group) was carried out. Control group involved 30 healthy donors without diseases of the musculoskeletal system.
 Results. In 1 and 12 months after the surgery, patients of the main group showed elevated levels of the factor inhibiting migration of macrophages (MIF), of macrophage stimulating protein (MSP), class A immunoglobulins (IgA), С3 and С4 complement components as compared to control, and also to each previous period. In 1 month after the surgery, the content of class M and G immunoglobulins (IgM and IgG) decreased relative to control; in 12 months after the surgery a more pronounced reduction was noted. Increase in serum concentrations of MIF, MSP, IgA, С3 and С4-complement components was noted in the comparison group in 1 and 12 months and also in comparison with the previous period. Reduction of the levels of IgM, IgG in 1 and 12 months after the operation was noted in comparison with control and with the previous period.
 Conclusion. A study of parameters of macrophage reaction, proteins of complement system and the main classes of immunoglobulins permits to identify signs of implant-associated inflammation in 1 and 12 months after surgery, and, consequently, to determine patients of risk groups that require additional diagnostics measures.

Precision Medicine in Neurology: The Inspirational Paradigm of Complement Therapeutics.

Precision medicine has emerged as a central element of healthcare science. Complement, a component of innate immunity known for centuries, has been implicated in the pathophysiology of numerous incurable neurological diseases, emerging as a potential therapeutic target and predictive biomarker. In parallel, the innovative application of the first complement inhibitor in clinical practice as an approved treatment of myasthenia gravis (MG) and neuromyelitis optica spectrum disorders (NMOSD) related with specific antibodies raised hope for the implementation of personalized therapies in detrimental neurological diseases. A thorough literature search was conducted through May 2020 at MEDLINE, EMBASE, Cochrane Library and ClinicalTrials.gov databases based on medical terms (MeSH)” complement system proteins” and “neurologic disease”. Complement’s role in pathophysiology, monitoring of disease activity and therapy has been investigated in MG, multiple sclerosis, NMOSD, spinal muscular atrophy, amyotrophic lateral sclerosis, Parkinson, Alzheimer, Huntington disease, Guillain–Barré syndrome, chronic inflammatory demyelinating polyneuropathy, stroke, and epilepsy. Given the complexity of complement diagnostics and therapeutics, this state-of-the-art review aims to provide a brief description of the complement system for the neurologist, an overview of novel complement inhibitors and updates of complement studies in a wide range of neurological disorders.

Predictive value of blood measurement of Complement System proteins and metabolic components for early detection of obstetric complications linked to poor placental function

Preeclampsia-eclampsia syndrome (PES) is associated with severe obstetric complications and there are no efficient methods available for an early detection. We studied blood concentration of some immunological and metabolic markers in association with obstetric outcome in healthy pregnant women and patients with obstetric risk factors, by ELISA and biochemical tests.Patients with complications showed higher levels of CRP and C4 positively correlated with Triglycerides and Cholesterol concentrations.Our results provide evidence that Immunological and metabolic alterations contribute to obstetric complications and that biomarkers linked to these alterations could be useful for an early detection of these problems.

Contribution of Complement System pathways to the killing of Leptospira spp.

The Complement System (CS) plays an important role in the immune response against leptospirosis and can be activated by the Alternative and Lectin Pathways (Innate Immunity) and by the Classical Pathway (Acquired Immunity). Here we analyzed a broad range of nonpathogenic and pathogenic Leptospira strains considering their interaction with each CS pathway. We determined bacterial survival rate and CS protein deposition in the presence of purified proteins, specific component depleted sera and NHS treated with the chelating agents EDTA (inhibits all three activation pathways) or EGTA (inhibits the Classical and Lectin Pathways). We suggest that the Lectin and the Alternative Pathways have an important role to eliminate saprophytic leptospires since i) approximately 50% survival of both saprophytic strains was observed in the presence of MBL-deficient serum; ii) approximately 50% survival of Leptospira biflexa Patoc I was observed in the presence of NHS – EGTA and iii) C1q-depleted serum caused significant bacterial lysis. In all serovars investigated the deposition of C5–C9 proteins on saprophytic Leptospira strains was more pronounced when compared to pathogenic species confirming previous studies in the literature. No difference on C3 deposition was observed between nonpathogenic and pathogenic strains. In conclusion, Leptospira strains interact to different degrees with CS proteins, especially those necessary to form MAC, indicating that some strains and specific ligands could favor the binding of certain CS proteins.

Complement split product C3c in saliva as biomarker for periodontitis and response to periodontal treatment.

Background and ObjectiveThe complement system is engaged in inflammatory reactions both in the periodontal pockets and in the periodontium itself, where it can mediate tissue destruction. The aim of this study was, first, to compare salivary levels of the total complement system protein C3 and its split product, fluid‐phase C3c in patients with periodontitis and periodontally healthy controls. Next, to determine if C3 and C3c levels had biomarker potential in diagnosing and monitoring periodontitis and its treatment. We hypothesized that salivary levels of total C3 and the split product C3c associated with the severity of periodontitis and reflected decreased inflammatory activity after periodontal treatment.MethodsAt baseline, stimulated saliva samples were collected from patients with periodontitis (n = 18) and periodontally healthy controls (n = 15). Subsequently, non‐surgical periodontal treatment was performed in the patients, and saliva sampling from patients was repeated two‐, six‐, and twelve weeks post‐treatment (NCT02913248 at clinicaltrials.gov).The patients were grouped as good and poor responders to treatment according to the achieved reduction in bleeding on probing (BOP).Salivary levels of C3 and C3c were quantified using sandwich ELISA.ResultsPatients with periodontitis had higher baseline levels of both total C3 and the split product C3c in saliva than did periodontally healthy controls (P < .0001). Receiver operating curve (ROC) analyses discriminated patients with periodontitis from controls based on both C3 (AUC (area under curve) = 0.91, P < .001) and C3c levels (AUC = 0.84, P < .001) in saliva. Periodontal treatment improved all clinical parameters (P < .01). Good responders (n = 10) had lower baseline levels of C3c than poor responders (n = 8), (P < .05), and baseline levels of C3c discriminated between good and poor responders (AUC = 0.80, P < .05).ConclusionIn conclusion, patients with periodontitis had higher salivary levels of C3c, and the C3c levels were predictive of reductions in BOP, that is, the poor responders. This suggests that salivary C3c levels possess potential to serve as a biomarker predicting the clinical response to non‐surgical periodontal treatment.

Systemic Alterations of Immune Response-Related Proteins during Glaucoma Development in the Murine Model DBA/2J.

Animal models of glaucoma, a neurodegenerative disease affecting the retina, offer the opportunity to study candidate molecular biomarkers throughout the disease. In this work, the DBA/2J glaucomatous mouse has been used to study the systemic levels of several proteins previously identified as potential biomarkers of glaucoma, along the pre- to post-glaucomatous transition. Serum samples obtained from glaucomatous and control mice at 4, 10, and 14 months, were classified into different experimental groups according to the optic nerve damage at 14 months old. Quantifications of ten serum proteins were carried out by enzyme immunoassays. Changes in the levels of some of these proteins in the transition to glaucomatous stages were identified, highlighting the significative decrease in the concentration of complement C4a protein. Moreover, the five-protein panel consisting of complement C4a, complement factor H, ficolin-3, apolipoprotein A4, and transthyretin predicted the transition to glaucoma in 78% of cases, and to the advanced disease in 89%. Our data, although still preliminary, suggest that disease development in DBA/2J mice is associated with important molecular changes in immune response and complement system proteins and demonstrate the utility of this model in identifying, at systemic level, potential markers for the diagnosis of glaucoma.

Gene expression analysis signifies the association of inflammatory proteins with the development of endometriosis

Endometriosis is primarily defined by the presence of endometrial glands and stroma outside of the uterine cavity. The diagnosis and management of the disease are challenging because of the unclear pathogenesis and heterogeneity of clinical symptoms.The main focus of the current study is to analyze the gene expression profiles of individuals with endometriosis and to clarify key candidate genes and pathways involved in the disease pathogenesis using the integrated bioinformatics analysis. The following mRNA expression profile datasets, namely GSE23339 and GSE25628, were obtained from the Gene Expression Omnibus database and differentially expressed genes (DEGs) with the following criteria p < 0.05 and [logFC] > 1 were identified. Totally, we identified 310 shared DEGs in the two datasets mentioned above. Subsequently, we conducted the enrichment analysis to discover the most critical pathways. The functional enrichment analysis showed that the identified DEGs mainly contributed to extracellular matrix organization and positive regulation of cell-cell adhesion. The PPI network was established for the analysis of DEGs, and the MCODE plug-in was applied for the characterization of the densely connected regions in the PPI network.Our findings propose a critical role of chemokines and complement system proteins in the promotion of endometriosis. These groups of genes might be considered a possible molecular signature for the early detection of endometriosis.

Mimicry between respiratory virus proteins and some human immune proteins

A comparative analysis on search for amino acid sequences in viral proteins causing respiratory infections (or respiratory infections syndrome) homologous to amino acid sequences from some human immune proteins was performed. The following viruses were used for comparative computer analysis: coronavirus (SARS-CoV), serotype C subgroup adenovirus C (adenoid 71 strain), measles virus (ICHINOSE-BA strain), rubella (Therien strain) and respiratory syncytial (B1 strain) virus. The search for homologous sequences in viral and human immune proteins was carried out by computer comparison of 12 amino acid fragments, which were assigned as homologous at identity in ≥ 8 positions. The data obtained showed that viral proteins contained homologous motifs in several host immune proteins involved in regulating both the inflammatory response and immune response. Mechanistically, all viruses studied were characterized by sequences homologous to host immune proteins such as complement system proteins, integrins, apoptosis inhibitory proteins, interleukins, and toll-like receptors. Such cellular proteins are actively involved in regulating host inflammatory process and immune response formation. Upon that, a set of host immune proteins, to which homologous fragments were found in viral proteins, was individual for each virus. Interestingly, the largest amount of homologous fragments (up to 20) was mainly concentrated in viral proteins with polymerase and protease activity suggesting that these proteins apart to their major role were involved in production of viral nucleic acids and might participate in regulating host immune system. Envelope, internal and non-structural viral proteins, homologous fragments were detected in much smaller quantities (from 1 to 4). In addition, two fragments homologous to various motifs of the same cellular protein were detected in some viral proteins. Thus, the data obtained further support our understanding that signs of immune system disorders in viral infections can result from multi-layered processes associated with modulation of host innate and adaptive immune system, and open up new approaches to study interaction of viruses with host immune system and identify new functions of viral proteins.

EPIGENOMIC FACTORS FOR THE DEVELOPMENT OF PERITONEAL ADHESIONS

Summary. The etiology of the development of adhesive disease — the most common postoperative complication — can be determined by epigenomic disorders related to various links of resistance and immunogenetic control.&#x0D; Purpose of the study. To study the epigenomic factors in the development of adhesive disease, the immune status of patients operated on in the abdominal cavity was studied. The comparison group included 55 patients with a complicated course of peritoneal commissural disease, the main group consisted of 59 patients operated on on the abdominal organs on the background of peritoneal commissural disease, the course of which was asymptomatic.&#x0D; Results and its discussion. The revealed epigenomic factors associated with the risk of developing adhesive disease: belongs to an increase in the concentration of acute phase proteins - ceruloplasmin, haptoglobin, C-reactive protein, C3 fragment of the complement system proteins, changes in the expression of adhesion molecule genes (CD31 increased by 10 %, CD54 increased to 24.1 % in comparison with the comparison group — 13.25 %).&#x0D; Conclusions. The results of our studies showed that patients with adhesive disease have a wide range of epigenome trigger factors. Epigenomic factors associated with the risk of developing adhesive disease include an increase in the concentration of acute phase proteins - ceruloplasmin, haptoglobin, C-reactive protein, C3 fragment of the complement system proteins, changes in the expression of adhesion molecule genes (CD31 increased by 10 %, CD54 increased to 24, 1 % compared with the comparison group - 13.25 %)

Evaluation of complement system proteins C3a, C5a and C6 in patients of endometriosis

BackgroundEndometriosis is a disease that shows auto-immune and chronic characteristics, suggesting a role for proteins mediating immune interactions in its pathophysiology. The aim was to evaluate C3a and C5a for their role in inflammatory responses and C6 as the down-stream interactor following our previous findings on C5 mRNA expression changes in endometriosis [1]. MethodsSera from 71 endometriosis patients and 77 women without endometriosis were taken. While the samples were taken only once from the controls, the patient samples were taken before, in 1st and in 7th days after laparoscopy. Levels of complement proteins C3a, C5a and C6 were measured with ELISA assays. MPV (Mean Platelet Volume), CRP (C-Reactive Protein) and NLR (Neutrophil-to-Leukocyte Ratio) were also analyzed from the retrospective data. ResultsC6 levels of early-stage patients at postoperative 1st day were significantly higher than controls. Patients with high MPV measurements had significantly higher C3a (p < 0.0001) and C6 (p < 0.05) levels than controls at all times of measurement. ConclusionsC6, an integral component of the membrane attack complex (MAC), could play a role at early disease-stage. The changes in levels of complement proteins and their relation to high MPV levels suggest a broader area of interplay for immune interactors in endometriosis. Although a bigger and longitudinal study design is needed to obtain more accurate results to evaluate these proteins as potential biomarkers, an important role of complement system within the pathophysiology of endometriosis is apparent.

Proteomic Analysis of Human Serum from Patients with Chronic Kidney Disease

Chronic kidney disease (CKD) is an important public health problem in the world. The aim of our research was to identify novel potential serum biomarkers of renal injury. ELISA assay showed that cytokines and chemokines IL-1β, IL-2, IL-4, IL-5, IL-6, IL-7, IL-8, IL-9, IL-10, IL-12 (p70), IL-13, IL-15, IL-17, Eotaxin, FGFb, G-CSF, GM-CSF, IP-10, MCP-1, MIP-1α, MIP-1β, PDGF-1bb, RANTES, TNF-α and VEGF were significantly higher (R > 0.6, p value < 0.05) in the serum of patients with CKD compared to healthy subjects, and they were positively correlated with well-established markers (urea and creatinine). The multiple reaction monitoring (MRM) quantification method revealed that levels of HSP90B2, AAT, IGSF22, CUL5, PKCE, APOA4, APOE, APOA1, CCDC171, CCDC43, VIL1, Antigen KI-67, NKRF, APPBP2, CAPRI and most complement system proteins were increased in serum of CKD patients compared to the healthy group. Among complement system proteins, the C8G subunit was significantly decreased three-fold in patients with CKD. However, only AAT and HSP90B2 were positively correlated with well-established markers and, therefore, could be proposed as potential biomarkers for CKD.

Immunological features of patients affected by Barraquer-Simons syndrome

BackgroundC3 hypocomplementemia and the presence of C3 nephritic factor (C3NeF), an autoantibody causing complement system over-activation, are common features among most patients affected by Barraquer-Simons syndrome (BSS), an acquired form of partial lipodystrophy. Moreover, BSS is frequently associated with autoimmune diseases. However, the relationship between complement system dysregulation and BSS remains to be fully elucidated. The aim of this study was to provide a comprehensive immunological analysis of the complement system status, autoantibody signatures and HLA profile in BSS. Thirteen subjects with BSS were recruited for the study. The circulating levels of complement components, C3, C4, Factor B (FB) and Properdin (P), as well as an extended autoantibody profile including autoantibodies targeting complement components and regulators were assessed in serum. Additionally, HLA genotyping was carried out using DNA extracted from peripheral blood mononuclear cells.ResultsC3, C4 and FB levels were significantly reduced in patients with BSS as compared with healthy subjects. C3NeF was the most frequently found autoantibody (69.2% of cases), followed by anti-C3 (38.5%), and anti-P and anti-FB (30.8% each). Clinical data showed high prevalence of autoimmune diseases (38.5%), the majority of patients (61.5%) being positive for at least one of the autoantibodies tested. The HLA allele DRB1*11 was present in 54% of BSS patients, and the majority of them (31%) were positive for *11:03 (vs 1.3% allelic frequency in the general population).ConclusionsOur results confirmed the association between BSS, autoimmunity and C3 hypocomplementemia. Moreover, the finding of autoantibodies targeting complement system proteins points to complement dysregulation as a central pathological event in the development of BSS.

Complement System Activation by Amyloid Aggregates of Aβ(1-40) and Aβ(1-42) Peptides: Facts and Hypotheses

Abstract—Here, we consider the problem of the activation of the complement system by amyloid aggregates, in particular, amyloid fibrils of the Aβ(1-40) and Aβ(1-42) peptides found in the brain of patients with Alzheimer’s disease . In 1992, based on the data on colocalization of amyloid inclusions with complement system proteins in the brains of patients with this disease, it was suggested that this system is directly activated by amyloids. This hypothesis has been supported by a number of subsequent publications. However, in this study, we did not find evidence to support this idea. The issue remains as to whether amyloids activate the complement system, and, if not, which mechanism is responsible for its activation. Here, we try to elucidate these issues.

Plasma metabonomics and proteomics studies on the anti-thrombosis mechanism of aspirin eugenol ester in rat tail thrombosis model

Aspirin eugenol eater (AEE), a new drug compound, was synthesized through the combination of aspirin and eugenol. Antithrombotic effects of AEE have been confirmed in carrageenan-induced rat tail thrombosis model. However, its mechanism is unclear. With the application of integrated approach combining proteomics and metabolomics, the profilings of protein and metabolite in plasma were examined in thrombosis rat pretreated with AEE, aspirin and eugenol, respectively. A clear separation of the plasma metabolic profiles from different groups was found in score plots. 15 metabolites related with the metabolism of fatty acid, energy and amino acid were found. A total of 144, 38, 41 and 54 differentially abundant proteins (DAPs) were identified in control, AEE, aspirin and eugenol group, respectively. Proteomic results showed that aspirin modulated 7 proteins in amino acid metabolism and 4 proteins in complement system; eugenol regulated the 8 proteins related with coagulation cascades and fibrinogen; AEE improved 3 proteins in TCA cycle and 3 in lipid metabolism. Integrated analysis suggested that AEE improved fatty acid, energy and lipid metabolism to against thrombosis. Results of this study indicated AEE had different action mechanism on thrombosis from aspirin and eugenol, and contribute to understanding the mechanisms of AEE on thrombosis. SignificanceThrombosis is a threat to human health, and there is an urgent need for new drug. In this study, compared with the model group, plasma metabolic profiles in AEE-treated rats were clearly separated; 15 metabolites and 38 proteins were picked out. These metabolites and proteins may assist in understanding the action mechanism of AEE on thrombosis. The results of plasma metabonomics and proteomics also revealed the different action mechanism among AEE, aspirin and eugenol on thrombosis. This study established the foundation to further evaluate the druggability of AEE on thrombosis treatment.

Progress of complement system in Alzheimer′s disease

Alzheimer′s disease (AD) is a growing global health concern with huge implications for individuals and society. In this review, current understanding of the pathogenesis of complement system in Alzheimer′s disease is outlined and current clinical laboratory diagnostic methods are discussed. Some theoretical basis and new ideas for seeking the biomarkers of AD and its treatment are also provided. Key words: Alzheimer disease; Complement system proteins; Biomarkers

Complement mediated tumor immune escape and its application in immune checkpoint inhibitors therapy

The complement system is an important part of the innate immune system. More evidence showed that the function of complement was not only limited to the elimination of pathogens and other risk factors from the body but also affected the immune escape mechanism of the tumor through different activating pathways. Because of the complex and important role of complement in the tumor, this review expounds the mechanism of complement system participating in immune escape of the tumor from three aspects: complement inherent components, complement activation products and complement regulatory proteins. Additionally, these mechanisms are expected to provide a new application of complement in tumor immunotherapy with immune checkpoint inhibitors. Key words: Tumor escape; Complement activation; Complement system proteins; Immunosuppressive agents; Immunotherapy

The role and progress of complement activation in antiphospholipid syndrome

Antiphospholipid syndrome(APS) is a non-inflammatory autoimmune disease caused by anti-phospholipid antibodies. In recent years, it has been found that over-activation of complement is the key factor leading to the formation of thrombosis and pathological pregnancy in APS. With more understanding of the role of complement activation in the pathogenesis of APS, methods of complement inhibition therapy have emerged one after another. Therefore, the detection of complement components is of great significance for the early diagnosis, treatment and monitoring of APS. Key words: Complement activation; Antiphospholipid syndrome; Complement system proteins; Biomarkers