Complement receptor 1 gene polymorphisms are associated with cardiovascular risk

Canonical and non-canonical roles of complement in atherosclerosis

Cardiovascular diseases are the leading cause of death globally, and atherosclerosis is the major contributor to the development and progression of cardiovascular diseases. Immune responses have a central role in the pathogenesis of atherosclerosis, with the complement system being an acknowledged contributor. Chronic activation of liver-derived and serum-circulating canonical complement sustains endothelial inflammation and innate immune cell activation, and deposition of complement activation fragments on inflamed endothelial cells is a hallmark of atherosclerotic plaques. However, increasing evidence indicates that liver-independent, cell-autonomous and non-canonical complement activities are underappreciated contributors to atherosclerosis. Furthermore, complement activation can also have atheroprotective properties. These specific detrimental or beneficial contributions of the complement system to the pathogenesis of atherosclerosis are dictated by the location of complement activation and engagement of its canonical versus non-canonical functions in a temporal fashion during atherosclerosis progression. In this Review, we summarize the classical and the emerging non-classical roles of the complement system in the pathogenesis of atherosclerosis and discuss potential strategies for therapeutic modulation of complement for the prevention and treatment of atherosclerotic cardiovascular disease.

Study on Potential Differentially Expressed Genes in Idiopathic Pulmonary Fibrosis by Bioinformatics and Next-Generation Sequencing Data Analysis

Idiopathic pulmonary fibrosis (IPF) is a chronic progressive lung disease with reduced quality of life and earlier mortality, but its pathogenesis and key genes are still unclear. In this investigation, bioinformatics was used to deeply analyze the pathogenesis of IPF and related key genes, so as to investigate the potential molecular pathogenesis of IPF and provide guidance for clinical treatment. Next-generation sequencing dataset GSE213001 was obtained from Gene Expression Omnibus (GEO), and the differentially expressed genes (DEGs) were identified between IPF and normal control group. The DEGs between IPF and normal control group were screened with the DESeq2 package of R language. The Gene Ontology (GO) and REACTOME pathway enrichment analyses of the DEGs were performed. Using the g:Profiler, the function and pathway enrichment analyses of DEGs were performed. Then, a protein-protein interaction (PPI) network was constructed via the Integrated Interactions Database (IID) database. Cytoscape with Network Analyzer was used to identify the hub genes. miRNet and NetworkAnalyst databaseswereused to construct the targeted microRNAs (miRNAs), transcription factors (TFs), and small drug molecules. Finally, receiver operating characteristic (ROC) curve analysis was used to validate the hub genes. A total of 958 DEGs were screened out in this study, including 479 up regulated genes and 479 down regulated genes. Most of the DEGs were significantly enriched in response to stimulus, GPCR ligand binding, microtubule-based process, and defective GALNT3 causes HFTC. In combination with the results of the PPI network, miRNA-hub gene regulatory network and TF-hub gene regulatory network, hub genes including LRRK2, BMI1, EBP, MNDA, KBTBD7, KRT15, OTX1, TEKT4, SPAG8, and EFHC2 were selected. Cyclothiazide and rotigotinethe are predicted small drug molecules for IPF treatment. Our findings will contribute to identification of potential biomarkers and novel strategies for the treatment of IPF, and provide a novel strategy for clinical therapy.

The Potential of Single Nucleotide Polymorphisms (SNPs) as Biomarkers and Their Association with the Increased Risk of Coronary Heart Disease: A Systematic Review

Human genetic analyses and epidemiological studies showed a potential association between several types of gene polymorphism and the development of coronary heart disease (CHD). Many studies on this pertinent topic need to be investigated further to reach an evidence-based conclusion. Therefore, in this current review, we describe several types of gene polymorphisms that are potentially linked to CHD. A systematic review using the databases EBSCO, PubMed, and ScienceDirect databases was searched until October of 2022 to find relevant studies on the topic of gene polymorphisms on risk factors for CHD, especially for the factors associated with single nucleotide polymorphisms (SNPs). The risk of bias and quality assessment was evaluated by Joanna Briggs Institute (JBI) guidelines. From keyword search results, a total of 6243 articles were identified, which were subsequently narrowed to 14 articles using prespecified inclusion criteria. The results suggested that there were 33 single nucleotide polymorphisms (SNPs) that can potentially increase the risk factors and clinical symptoms of CHD. This study also indicated that gene polymorphisms had a potential role in increasing CHD risk factors that were causally associated with atherosclerosis, increased homocysteine, immune/inflammatory response, Low-Density Lipoprotein (LDL), arterial lesions, and reduction of therapeutic effectiveness. In conclusion, the findings of this study indicate that SNPs may increase risk factors for CHD and SNPs show different effects between individuals. This demonstrates that knowledge of SNPs on CHD risk factors can be used to develop biomarkers for diagnostics and therapeutic response prediction to decide successful therapy and become the basis for defining personalized medicine in future.

Effect of Avian Influenza Virus subtype H9N2 on the expression of complement-associated genes in chicken erythrocytes

The H9N2 subtype avian influenza virus can infect both chickens and humans. Previous studies have reported a role for erythrocytes in immunity. However, the role of H9N2 against chicken erythrocytes and the presence of complement-related genes in erythrocytes has not been studied. This research investigated the effect of H9N2 on complement-associated gene expression in chicken erythrocytes. The expression of complement-associated genes (C1s, C1q, C2, C3, C3ar1, C4, C4a, C5, C5ar1, C7, CD93 and CFD) was detected by reverse transcription-polymerase chain reaction (RT-PCR). Quantitative Real-Time PCR (qRT-PCR) was used to analyse the differential expression of complement-associated genes in chicken erythrocytes at 0 h, 2 h, 6 h and 10 h after the interaction between H9N2 virus and chicken erythrocytes in vitro and 3, 7 and 14 d after H9N2 virus nasal infection of chicks. Expression levels of C1q, C4, C1s, C2, C3, C5, C7 and CD93 were significantly up-regulated at 2 h and significantly down-regulated at 10 h. Gene expression levels of C1q, C3ar1, C4a, CFD and C5ar1 were seen to be different at each time point. The expression levels of C1q, C4, C1s, C2, C3, C5, C7, CFD, C3ar1, C4a and C5ar1 were significantly up-regulated at 7 d and the gene expression of levels of C3, CD93 and C5ar1 were seen to be different at each time point. The results confirmed that all the complement-associated genes were expressed in chicken erythrocytes and showed the H9N2 virus interaction with chicken erythrocytes and subsequent regulation of chicken erythrocyte complement-associated genes expression. This study reported, for the first time, the relationship between H9N2 and complement system of chicken erythrocytes, which will provide a foundation for further research into the prevention and control of H9N2 infection.

Identification of candidate biomarkers and therapeutic agents for heart failure by bioinformatics analysis

INTRODUCTION

Heart failure (HF) is a heterogeneous clinical syndrome and affects millions of people all over the world. HF occurs when the cardiac overload and injury, which is a worldwide complaint. The aim of this study was to screen and verify hub genes involved in developmental HF as well as to explore active drug molecules.

METHODS

The expression profiling by high throughput sequencing of GSE141910 dataset was downloaded from the Gene Expression Omnibus (GEO) database, which contained 366 samples, including 200 heart failure samples and 166 non heart failure samples. The raw data was integrated to find differentially expressed genes (DEGs) and were further analyzed with bioinformatics analysis. Gene ontology (GO) and REACTOME enrichment analyses were performed via ToppGene; protein-protein interaction (PPI) networks of the DEGs was constructed based on data from the HiPPIE interactome database; modules analysis was performed; target gene-miRNA regulatory network and target gene-TF regulatory network were constructed and analyzed; hub genes were validated; molecular docking studies was performed.

RESULTS

A total of 881 DEGs, including 442 up regulated genes and 439 down regulated genes were observed. Most of the DEGs were significantly enriched in biological adhesion, extracellular matrix, signaling receptor binding, secretion, intrinsic component of plasma membrane, signaling receptor activity, extracellular matrix organization and neutrophil degranulation. The top hub genes ESR1, PYHIN1, PPP2R2B, LCK, TP63, PCLAF, CFTR, TK1, ECT2 and FKBP5 were identified from the PPI network. Module analysis revealed that HF was associated with adaptive immune system and neutrophil degranulation. The target genes, miRNAs and TFs were identified from the target gene-miRNA regulatory network and target gene-TF regulatory network. Furthermore, receiver operating characteristic (ROC) curve analysis and RT-PCR analysis revealed that ESR1, PYHIN1, PPP2R2B, LCK, TP63, PCLAF, CFTR, TK1, ECT2 and FKBP5 might serve as prognostic, diagnostic biomarkers and therapeutic target for HF. The predicted targets of these active molecules were then confirmed.

CONCLUSION

The current investigation identified a series of key genes and pathways that might be involved in the progression of HF, providing a new understanding of the underlying molecular mechanisms of HF.

The Prevalence and Risk Factors of Cerebral Microbleeds: A Community-Based Study in China

Introduction

Cerebral microbleeds (CMBs) are frequently found in the healthy elderly. However, data on the prevalence and risk factors of CMBs in the general population of China are lacking.

Methods

A cross-sectional study focusing on the prevalence and risk factors of CMBs was conducted in stroke-free elderly from Shanghai Wuliqiao community. MRI was performed at 3Tesla and cardiovascular risk factors (eg, age, smoking history, and hypertension), cerebral small vessel disease (CSVD) markers (eg, white matter hyperintensities, lacunar infarction, and enlarged perivascular space) and genetic information (eg, APOE, CR1) were recorded. Poisson regression was used to analyze the risk factors of the presence and location of microbleeds.

Results

A total of 199 participants (70.8±7.2 years old; male 31.2%) were finally included in our analysis. The overall prevalence of CMBs was 12.6% (25/199) and increased with age from 7.5% (55-64 years old) to 19.3% (over 75 years old). Of those with CMBs, most of them (16/25) located in the deep/mixed region and had 1-2 CMBs (18/25). Poisson regression analysis showed that white matter hyperintensities (OR=1.22, 95% CI: 1.16-1.29), APOE ε4+ carrier (OR=2.16, 95% CI: 1.18-3.96) and CR1 non-F/F isoform (OR=7.78, 95% CI: 4.34-13.96) were associated with CMBs. Further analysis found that in addition to the above three risk factors, hypertension (OR=2.98, 95% CI: 1.16-7.64), lacunar infarction (OR=2.39, 95% CI: 1.19-4.81) also increased the risk of deep/mixed CMBs.

Conclusion

The prevalence of cerebral microbleeds is similar to other countries. Cardiovascular risk factors, CSVD markers, and genetic factors (APOE ε4, CR1 non-F/F isoform) were associated with CMBs, suggesting an interaction of multiple pathogenesis in Chinese stroke-free community population.

Therapeutic Lessons to be Learned From the Role of Complement Regulators as Double-Edged Sword in Health and Disease

The complement system is an important part of the innate immune system, providing a strong defense against pathogens and removing apoptotic cells and immune complexes. Due to its strength, it is important that healthy human cells are protected against damage induced by the complement system. To be protected from complement, each cell type relies on a specific combination of both soluble and membrane-bound regulators. Their importance is indicated by the amount of pathologies associated with abnormalities in these complement regulators. Here, we will discuss the current knowledge on complement regulatory protein polymorphisms and expression levels together with their link to disease. These diseases often result in red blood cell destruction or occur in the eye, kidney or brain, which are tissues known for aberrant complement activity or regulation. In addition, complement regulators have also been associated with different types of cancer, although their mechanisms here have not been elucidated yet. In most of these pathologies, treatments are limited and do not prevent the complement system from attacking host cells, but rather fight the consequences of the complement-mediated damage, using for example blood transfusions in anemic patients. Currently only few drugs targeting the complement system are used in the clinic. With further demand for therapeutics rising linked to the wide range of complement-mediated disease we should broaden our horizon towards treatments that can actually protect the host cells against complement. Here, we will discuss the latest insights on how complement regulators can benefit therapeutics. Such therapeutics are currently being developed extensively, and can be categorized into full-length complement regulators, engineered complement system regulators and antibodies targeting complement regulators. In conclusion, this review provides an overview of the complement regulatory proteins and their links to disease, together with their potential in the development of novel therapeutics.

Circulating Neutrophils Do Not Predict Subclinical Coronary Artery Disease in Women with Former Preeclampsia

: Introduction: Preeclampsia (PE) represents a hypertensive pregnancy disorder that is associated with increased cardiovascular disease (CVD) risk. This increased risk has been attributed to accelerated atherosclerosis, with inflammation being a major contributor. Neutrophils play an important role in the onset and progression of atherosclerosis and have been associated with vascular damage in the placenta as well as the chronic inflammatory state in women with PE. We therefore investigated whether circulating neutrophil numbers or reactivity were associated with the presence and severity of subclinical atherosclerosis in women with a history of PE.

METHODS

Women aged 45-60 years with a 10 to 20 years earlier history of early onset preeclampsia (delivery <34 weeks of gestation) (n = 90), but without symptomatic CVD burden were screened for the presence of subclinical coronary artery disease (CAD) using both contrast-enhanced and non-contrast coronary CT angiography. Subclinical CAD was defined as a coronary artery calcium (CAC) score ≥100 Agatston Units and/or ≥50% coronary luminal stenosis. We assessed whether the numbers and activity of circulating neutrophils were associated with the presence of subclinical CAD and as secondary outcome measurements, with the presence of any calcium (CAC score > 0 AU) or stenosis, categorized as absent (0%), minimal to mild (>0 and <50%), and moderate to severe (≥50%) narrowing of the coronary artery. Blood was drawn just before CT and neutrophil numbers were assessed by flow cytometry. In addition, the presence of the chemokine receptors CXCR2 and CXCR4, which are known to be instrumental in neutrophil recruitment, and neutrophil activity upon stimulation with the bacterial peptide N-Formylmethionyl-leucyl-phenylalanine (fMLF) was assessed by flow cytometry.

RESULTS

Of the participating women, with an average age of 49 years, 13% (12 out of 90) presented with subclinical signs of CAD (CAC score ≥100 AU and/or ≥50% luminal stenosis), and 37% (33 out of 90) had a positive CAC score (>0). Total white blood cell count and neutrophil counts were not associated with the presence of subclinical CAD or with a positive CAC score. When assessing the presence of the chemokine receptors CXCR4 and CXCR2, we observed a slight decrease of neutrophil CXCR2 expression in women with CAC (median MFI 22.0 [interquartile range (IQR) 20.2-23.8]) compared to women without CAC (23.8 [IQR 21.6-25.6], p = 0.02). We observed no differences regarding neutrophil CXCR4 expression. In addition, expression of the early activity marker CD35 was slightly lower on neutrophils of women with subclinical CAD (median MFI 1.6 [IQR 1.5-1.9] compared to 1.9 [IQR 1.7-2.1] in women without CAD, p = 0.02). However, for all findings, statistical significance disappeared after adjustment for multiple testing.

CONCLUSION

Our findings indicate that neutrophil counts and (re)activity are not directly associated with silent CAD disease burden and as such are not suitable as biomarkers to predict the presence of subclinical CAD in a high-risk population of women with a history of preeclampsia.

The role of the complement factor B-arginase-polyamine molecular axis in uremia-induced cardiac remodeling in mice

The role of complement system in heart diseases is controversial. Besides, the mechanisms by which complement components participate in cardiac remodeling (CR) and heart failure during uremia are unclear. In this study, 5/6 nephrectomy was performed to adult mice to establish the uremic model and CR deteriorated over the course of uremia. Although complement pathways were not further activated over the course of the disease, soluble complement factor B (CFB) was upregulated at post-nephrectomy day 90 (PNx90) compared with PNx30. Further, CFB notably deteriorated CR in uremic mice but this effect was reversed by depletion of macrophages with liposomal clodronate. In vivo and in vitro CFB upregulated arginase 1 (ARG1) expression, increased ARG1 enzymatic activity, and stimulated the syntheses of ornithine, leading to polyamine overproduction in macrophages. Putrescine, an important polyamine, promoted cardiac fibroblast proliferation and collagen production, resulting in progressive CR. In vivo the inhibition of ARG1 activity with N^ω -hydroxyl-l-arginine remarkably improved the general survival rates, inhibited the infiltration of cardiac fibroblasts, and alleviated progression of CR in uremic mice. Taken together, the CFB-ARG1-putrescine axis is related to progression of CR and ARG1 hyperactivity in macrophages may provide a novel therapeutic target against the heart injury in uremia.

Role of complement system in pathological remodeling of the vascular wall

Cardiovascular diseases (CVD) remain the major cause of morbidity and mortality in Europe. The clinical complications associated to arterial wall rupture involve intimal cap rupture in complicated atherosclerotic plaques and medial rupture in abdominal aortic aneurysm (AAA). The mechanisms underlying pathological vascular remodeling include lipid accumulation, cell proliferation, redox imbalance, proteolysis, leukocyte infiltration, cell death, and eventually, thrombosis. The complement system could participate in vascular remodeling by several mechanisms, from an initial protective response that aims in the clearing of cell debris to a potential deleterious role participating in leukocyte chemotaxis and cell activation and bridging innate and adaptive immunity. We have reviewed the presence and distribution of complement components, as well as the triggers of complement activation in atherosclerotic plaques and AAA, to later assess the functional consequences of complement modulation in experimental models of pathological vascular remodeling and the potential role of complement components as potential circulating biomarkers of CVD. On the whole, complement system is a key mechanism involved in vascular remodelling, which could be useful in the diagnostic/prognostic setting, as well as a potential therapeutic target, of CVD.

On the origin of proteins in human drusen: The meet, greet and stick hypothesis

Retinal drusen formation is not only a clinical hallmark for the development of age-related macular degeneration (AMD) but also for other disorders, such as Alzheimer's disease and renal diseases. The initiation and growth of drusen is poorly understood. Attention has focused on lipids and minerals, but relatively little is known about the origin of drusen-associated proteins and how they are retained in the space between the basal lamina of the retinal pigment epithelium and the inner collagenous layer space (sub-RPE-BL space). While some authors suggested that drusen proteins are mainly derived from cellular debris from processed photoreceptor outer segments and the RPE, others suggest a choroidal cell or blood origin. Here, we reviewed and supplemented the existing literature on the molecular composition of the retina/choroid complex, to gain a more complete understanding of the sources of proteins in drusen. These "drusenomics" studies showed that a considerable proportion of currently identified drusen proteins is uniquely originating from the blood. A smaller, but still large fraction of drusen proteins comes from both blood and/or RPE. Only a small proportion of drusen proteins is uniquely derived from the photoreceptors or choroid. We next evaluated how drusen components may "meet, greet and stick" to each other and/or to structures like hydroxyapatite spherules to form macroscopic deposits in the sub-RPE-BL space. Finally, we discuss implications of our findings with respect to the previously proposed homology between drusenogenesis in AMD and plaque formation in atherosclerosis.

Genetic polymorphisms in complement receptor 1 gene and its association with HBV-related liver disease: A case-control study

BACKGROUND

Several investigators have reported that complement receptor 1 (CR1) likely play a role in the pathogenesis of tumors, autoimmune and inflammatory diseases. However, the association of genetic polymorphisms of CR1 with risk of hepatitis B virus (HBV)-related liver disease remains unexplored.

METHODS

In a case-control study of 399 HBV-related liver disease patients and 227 healthy controls, we genotyped two SNPs in CR1 (rs3811381 and rs2274567) and assessed their associations with risk of HBV-related liver disease.

RESULTS

No significant differences were observed in the frequency distribution of genotypes or alleles between CR1 rs3811381 and rs2274567 polymorphisms in patients and controls. However, stratification analysis indicated that these two CR1 polymorphisms may contribute to the risk of HBV- hepatocellular carcinoma (HCC) and chronic hepatitis B (CHB) in subgroups of males, alcohol drinkers and nonsmokers. Further, our results showed that the rs3811381 polymorphism may contribute to HBV-HCC risk in subgroups of older and younger subjects, while the G allele, AG and the combined AG + GG genotypes of rs2274567 may be risk factors for HBV-HCC in younger subjects. In addition, our results indicated that subjects who carried the rs3811381 G allele and the rs2274567 AG genotype were at decreased risk of HBV- liver cirrhosis (LC) in subgroups of females.

CONCLUSIONS

Our results support the hypothesis that the CR1 gene rs3811381 and rs2274567 polymorphisms may contribute to HBV-HCC and HBV-CHB risk, particularly in subgroups of males, alcohol drinkers, nonsmokers, while these two CR1 polymorphisms were found to associate with decreased risk of HBV-LC, particularly in females. Further validation of these results is warranted.

Association of complement receptor 1 gene polymorphisms with cognitive function

Previous evidence suggest involvement of the complement receptor 1 (CR1) in development of Alzheimer’s disease. We investigated the association of CR1 gene polymorphisms with cognitive function in older subjects. Single nucleotide polymorphisms (SNPs) within the CR1 region on chromosome 1 (n = 73) were assessed in 5,244 participants in the PROspective Study of Pravastatin in the Elderly at Risk (51.9% female, mean age 75.3 yr). Linear regression, adjusted for age, sex, country, and use of pravastatin, was used to assess the association between the SNPs and cognitive function. All 73 SNPs within the genomic region of the CR1 gene on chromosome 1 were extracted. Eighteen were independent, according to a relatively stringent R² threshold of >0.8 with LDlink. Twelve of the 18 investigated CR1 SNPs were significantly associated with a decline in cognitive function (all P < 0.05). These data indicate that genetic variation within the CR1 gene is associated not only with Alzheimer’s disease, but also with general cognitive function during late life.