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1.
Arch Virol ; 166(3): 767-778, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33420816

RESUMO

Complement component 1 Q subcomponent-binding protein (C1QBP) has been shown to interact with the porcine circovirus type 2 (PCV2) Cap protein. Here, using yeast two-hybrid (Y2H) and co-immunoprecipitation assays, as well as laser confocal microscopy, the interaction between C1QBP and Cap was confirmed. Furthermore, overexpression of C1QBP in cells altered the intracellular location of Cap, which was observed using confocal microscopy and verified by detection of Cap in nuclear protein extracts in a Western blot assay. By inhibiting nuclear transport of Cap, overexpression of C1QBP downregulated PCV2 proliferation in PK-15 cells, as determined by quantitative polymerase chain reaction (qPCR). As C1QBP plays a similar role in a fusion of green fluorescent protein (GFP) with the Cap nuclear localisation signal (NLS) sequence, (CapNLS-GFP), we propose that the target site for C1QBP in Cap is possibly located in the NLS region. Considering all the results together, this study demonstrated that C1QBP interacts with the Cap NLS region, resulting in changes in the intracellular localisation of the Cap protein. We confirmed that overexpression of C1QBP inhibits the proliferation of PCV2, and this is possibly related to the function of C1QBP in controlling nuclear transport of Cap.


Assuntos
Transporte Ativo do Núcleo Celular/fisiologia , Proteínas do Capsídeo/metabolismo , Circovirus/crescimento & desenvolvimento , Complemento C1q/metabolismo , Replicação Viral/fisiologia , Animais , Linhagem Celular , Chlorocebus aethiops , DNA Viral/metabolismo , Células HEK293 , Humanos , Domínios Proteicos/genética , Interferência de RNA , RNA Interferente Pequeno/genética , Reação em Cadeia da Polimerase em Tempo Real , Suínos , Células Vero
2.
PLoS Negl Trop Dis ; 14(9): e0008602, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32886656

RESUMO

Besides the common Fc receptor (FcR)-mediated mechanism of antibody-dependent enhancement (ADE), Ebola virus (EBOV) is known to utilize the complement component C1q for ADE of infection. This mechanism is FcR-independent and mediated by cross-linking of virus-antibody-C1q complexes to cell surface C1q receptors, leading to enhanced viral entry into cells. Using confocal microscopy, we found that virus-like particles (VLPs) consisting of EBOV glycoprotein, nucleoprotein, and matrix protein attached to the surface of human kidney 293 cells more efficiently in the presence of an ADE monoclonal antibody and C1q than with the antibody or C1q alone, and that there was no significant difference in the efficiency of VLP uptake into endosomes between the C1q-mediated ADE and non-ADE entry. Accordingly, both ADE and non-ADE infection were similarly decreased by inhibitors of the signaling pathways known to be required for endocytosis. These results suggest that C1q-mediated ADE of EBOV infection is simply caused by increased attachment of virus particles to the cell surface, which is distinct from the mechanism of FcR-mediated ADE requiring intracellular signaling to promote phagocytosis/macropinocytosis.


Assuntos
Anticorpos Facilitadores/imunologia , Complemento C1q/metabolismo , Ebolavirus/imunologia , Doença pelo Vírus Ebola/imunologia , Glicoproteínas de Membrana/metabolismo , Receptores de Complemento/metabolismo , Animais , Anticorpos Monoclonais/imunologia , Anticorpos Antivirais/imunologia , Linhagem Celular , Chlorocebus aethiops , Ebolavirus/patogenicidade , Endocitose/imunologia , Células HEK293 , Doença pelo Vírus Ebola/patologia , Humanos , Células Vero , Proteínas Virais/imunologia , Proteínas Virais/metabolismo , Ligação Viral
3.
Nat Commun ; 11(1): 3753, 2020 07 27.
Artigo em Inglês | MEDLINE | ID: mdl-32719333

RESUMO

Reactive astrocytes have been implicated in the pathogenesis of neurodegenerative diseases, including a non-cell autonomous effect on motor neuron survival in ALS. We previously defined a mechanism by which microglia release three factors, IL-1α, TNFα, and C1q, to induce neurotoxic astrocytes. Here we report that knocking out these three factors markedly extends survival in the SOD1G93A ALS mouse model, providing evidence for gliosis as a potential ALS therapeutic target.


Assuntos
Esclerose Amiotrófica Lateral/metabolismo , Esclerose Amiotrófica Lateral/patologia , Astrócitos/metabolismo , Complemento C1q/metabolismo , Progressão da Doença , Interleucina-1alfa/metabolismo , Fator de Necrose Tumoral alfa/metabolismo , Animais , Complemento C3/metabolismo , Modelos Animais de Doenças , Humanos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Microglia , Superóxido Dismutase-1/metabolismo
4.
Proc Natl Acad Sci U S A ; 117(29): 17381-17388, 2020 07 21.
Artigo em Inglês | MEDLINE | ID: mdl-32632018

RESUMO

Adiponectin (Acrp30) is an adipokine associated with protection from cardiovascular disease, insulin resistance, and inflammation. Although its effects are conventionally attributed to binding Adipor1/2 and T-cadherin, its abundance in circulation, role in ceramide metabolism, and homology to C1q suggest an overlooked role as a lipid-binding protein, possibly generalizable to other C1q/TNF-related proteins (CTRPs) and C1q family members. To investigate this, adiponectin, representative family members, and variants were expressed in Expi293 cells and tested for binding to lipids in liposomes using density centrifugation. Binding to physiological lipids were also analyzed using gradient ultracentrifugation, liquid chromatography-mass spectrometry, and shotgun lipidomics. Interestingly, adiponectin selectively bound several anionic phospholipids and sphingolipids, including phosphatidylserine, ceramide-1-phosphate, glucosylceramide, and sulfatide, via the C1q domain in an oligomerization-dependent fashion. Binding to lipids was observed in liposomes, low-density lipoproteins, cell membranes, and plasma. Other CTRPs and C1q family members (Cbln1, CTRP1, CTRP5, and CTRP13) also bound similar lipids. These findings suggest that adiponectin and CTRPs function not only as hormones, but also as lipid opsonins, as may other C1q family proteins.


Assuntos
Adiponectina/metabolismo , Complemento C1q/metabolismo , Fosfolipídeos/metabolismo , Esfingolipídeos/metabolismo , Fator de Necrose Tumoral alfa/metabolismo , Adipocinas/metabolismo , Adiponectina/genética , Animais , Ânions , Membrana Celular , LDL-Colesterol , Humanos , Metabolismo dos Lipídeos , Lipidômica , Lipoproteínas/metabolismo , Lipossomos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Proteínas Opsonizantes/metabolismo , Plasma
5.
Life Sci ; 256: 117913, 2020 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-32526287

RESUMO

The growing evidence has been tried to explain and characterize C1q/TNF- related proteins (CTRPs) family as the potential diagnostic or therapeutic targets of obesity-related metabolic disorders such as insulin resistance, type 2 diabetes (T2D), and cardiovascular disorders. However, the underlying mechanism is still obscure. Unraveling the signaling pathways downstream of CTRP family members is of great interest and could certainly be beneficial for finding new insights into therapeutic strategies for improving metabolic abnormalities. This review focused on the role of CTRP members in the initiation and development of obesity-related metabolic disorders with a focus on T2D and cardiovascular diseases. Here we summarize and discuss the role of CTRPs in the regulation of insulin signaling, inflammatory pathways, and energy metabolism, and other signaling pathways pertinent to the pathogenesis of T2D and cardiovascular diseases. We also review available clinical studies to better elucidate the roles of these potential molecules in the initiation and development of the afore-mentioned disorders.


Assuntos
Doenças Cardiovasculares/etiologia , Complemento C1q/metabolismo , Diabetes Mellitus Tipo 2/etiologia , Obesidade/complicações , Fator de Necrose Tumoral alfa/metabolismo , Animais , Doenças Cardiovasculares/metabolismo , Complemento C1q/genética , Diabetes Mellitus Tipo 2/metabolismo , Metabolismo Energético , Regulação da Expressão Gênica , Humanos , Inflamação/metabolismo , Resistência à Insulina , RNA Mensageiro , Transdução de Sinais , Fator de Necrose Tumoral alfa/genética
6.
Immunogenetics ; 72(5): 305-314, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32556499

RESUMO

Several genetic studies have implicated genes that encode for components of the innate immune response in tuberculosis (TB) susceptibility. The complement system is an early player in the innate immune response and provides the host with initial protection by promoting phagocytosis of apoptotic or necrotic cells. The C1q molecule is the first component of the classical pathway that leads to the activation of complement by binding to immune complexes and is encoded by the C1Q gene cluster. We investigated variants in this region to determine its association with TB susceptibility. Five single nucleotide polymorphisms (SNPs) (rs12033074, rs631090, rs172378, rs587585, and rs665691) were genotyped using TaqMan® SNP assays in 456 TB cases and 448 healthy controls and analysed by logistic regression models. The rs587585 variant showed a significant additive allelic association where the minor G allele was found more frequently in TB cases than in controls in both the discovery (p = 0.023; OR = 1.30; 95% CI, 1.04-1.64) and validation cohort (p = 0.038; OR = 1.31; 95% CI, 1.22-1.40). In addition, we detected increased C1qA expression when comparing cases and controls (p = 0.037) and linked this to a dosage effect of the G allele, which increased C1qA expression in TB cases. This is the first study to report the association of C1Q gene polymorphisms with progression to tuberculosis.


Assuntos
Complemento C1q/genética , Complemento C1q/metabolismo , Predisposição Genética para Doença/genética , Tuberculose/genética , Adulto , Grupo com Ancestrais do Continente Africano/genética , Alelos , Estudos de Casos e Controles , Feminino , Estudos de Associação Genética , Genótipo , Humanos , Masculino , Pessoa de Meia-Idade , Família Multigênica , Polimorfismo de Nucleotídeo Único , Tuberculose/imunologia , Adulto Jovem
7.
Am J Physiol Regul Integr Comp Physiol ; 318(6): R1047-R1057, 2020 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-32374620

RESUMO

Preeclampsia is a spontaneously occurring, pregnancy-specific syndrome that is clinically diagnosed by new onset hypertension and proteinuria. Epidemiological evidence describes an association between a history of preeclampsia and increased risk for cardiovascular disease in later life; however, the mechanism(s) driving this relationship are unclear. Our study aims to leverage a novel preeclampsia-like mouse model, the C1q-/- model, to help elucidate the acute and persistent vascular changes during and following a preeclampsia-like pregnancy. Female C57BL/6J mice were mated to C1q-/- male mice to model a preeclampsia-like pregnancy ("PE-like"), and the maternal cardiovascular phenotype (blood pressure, renal function, systemic glycocalyx, and ex vivo vascular function) was assessed in late pregnancy and postpartum at 6 and 10 mo of age. Uncomplicated, normotensive pregnancies (female C57BL/6J bred to male C57BL/6J mice) served as age-matched controls. In pregnancy, PE-like dams exhibited increased systolic and diastolic pressure during mid- and late gestation, renal dysfunction, fetal growth restriction, and reduced placental efficiency. Ex vivo wire myography studies of mesenteric arteries revealed severe pregnancy-specific endothelial-dependent and -independent vascular dysfunction. At 3 and 7 mo postpartum (6 and 10 mo old, respectively), hypertension resolved in PE-like dams, whereas mild vascular dysfunction persisted at 3 mo postpartum. In conclusion, the female C57BL/6J-by-male C57BL/6J C1q-/- model recapitulates many aspects of the human preeclampsia syndrome in a low-risk, wild-type female mouse. The pregnancy-specific phenotype results in systemic maternal endothelial-dependent and -independent vascular dysfunction that persists postpartum.


Assuntos
Complemento C1q/metabolismo , Pré-Eclâmpsia/metabolismo , Animais , Pressão Sanguínea/fisiologia , Complemento C1q/genética , Modelos Animais de Doenças , Feminino , Masculino , Camundongos , Camundongos Knockout , Placenta/irrigação sanguínea , Pré-Eclâmpsia/genética , Gravidez
8.
J Psychosom Res ; 133: 110105, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32272297

RESUMO

BACKGROUND: The complement system is involved in multiple biological processes including inflammation, synaptic pruning, and apoptosis. However, it is not well understood whether peripheral complement C1q levels are altered in major depressive disorder (MDD) patients. OBJECTIVE: This study aimed at assessing serum levels of complement C1q in MDD patients using a cross-sectional, case-control design. Also, the correlations between complement C1q and inflammation and lipid profile in patients with MDD were also assessed. METHODS: Serum complement C1q levels were measured by ADVIA 2400 biochemical analyzer in 160 patients with MDD diagnosed using International Classification of Diseases-10 criteria (ICD-10) and were compared with those of 159 healthy controls between January 2017 to May 2019. Then correlation analysis was carried out between the level of serum complement C1q among MDD patients with inflammation and lipid profile. RESULTS: Serum complement C1q levels were higher in MDD patients than in controls (P < .0001) and the difference between the two groups was small (r = 0.239 [0.128 to 0.350]). We found that serum complement C1q concentrations was positively correlated with HAMD-24 score (r = 0.234, P = .003) and log hs-CRP (r = 0.334, P < .001). CONCLUSION: We found serum complement C1q levels were significantly higher in MDD patients than in controls. The current results suggest that the dysfunction of complement C1q may be involved in the pathophysiology of MDD.


Assuntos
Complemento C1q/metabolismo , Transtorno Depressivo Maior/sangue , Adulto , Estudos de Casos e Controles , Estudos Transversais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
9.
Immunol Cell Biol ; 98(4): 305-317, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32142167

RESUMO

Antibody-dependent complement activity is associated not only with autoimmune morbidity, but also with antitumor efficacy. In infectious disease, both recombinant monoclonal antibodies and polyclonal antibodies generated in natural adaptive responses can mediate complement activity to protective, therapeutic or disease-enhancing effect. Recent advances have contributed to the structural resolution of molecular complexes involved in antibody-mediated complement activation, defining the avid nature of participating interactions and pointing to how antibody isotype, subclass, hinge flexibility, glycosylation state, amino acid sequence and the contextual nature of the cognate antigen/epitope are all factors that can determine complement activity through impact on antibody multimerization and subsequent recruitment of complement component 1q. Beyond the efficiency of activation, complement activation products interact with various cell types that mediate immune adherence, trafficking, immune education and innate functions. Similarly, depending on the anatomical location and extent of activation, complement can support homeostatic restoration or be leveraged by pathogens or neoplasms to enhance infection or promote tumorigenic microenvironments, respectively. Advances in means to suppress complement activation by intravenous immunoglobulin (IVIG), IVIG mimetics and complement-intervening antibodies represent proven and promising exploratory therapeutic strategies, while antibody engineering has likewise offered frameworks to enhance, eliminate or isolate complement activation to interrogate in vivo mechanisms of action. Such strategies promise to support the optimization of antibody-based drugs that are able to tackle emerging and difficult-to-treat diseases by improving our understanding of the synergistic and antagonistic relationships between antibody mechanisms mediated by Fc receptors, direct binding and the products of complement activation.


Assuntos
Anticorpos Monoclonais/imunologia , Doenças Transmissíveis/imunologia , Ativação do Complemento/imunologia , Proteínas do Sistema Complemento/imunologia , Neoplasias/imunologia , Animais , Anticorpos Monoclonais/efeitos adversos , Anticorpos Monoclonais/metabolismo , Antígenos/imunologia , Antígenos/metabolismo , Autoanticorpos/efeitos adversos , Autoanticorpos/imunologia , Engenharia Biomédica , Doenças Transmissíveis/microbiologia , Doenças Transmissíveis/patologia , Doenças Transmissíveis/virologia , Complemento C1q/química , Complemento C1q/imunologia , Complemento C1q/metabolismo , Proteínas do Sistema Complemento/química , Proteínas do Sistema Complemento/metabolismo , Humanos , Fragmentos Fc das Imunoglobulinas/imunologia , Imunoglobulina G/química , Imunoglobulina G/imunologia , Imunoglobulina G/ultraestrutura , Neoplasias/patologia , Receptores Fc/imunologia , Receptores Fc/metabolismo
10.
Mol Immunol ; 120: 187-195, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32179338

RESUMO

BACKGROUND: To facilitate better discrimination between patients with active tuberculosis (TB) and latent TB infection (LTBI), whole blood transcriptomic studies have been performed to identify novel candidate host biomarkers. SERPING1, which encodes C1-inhibitor (C1-INH), the natural inhibitor of the C1-complex has emerged as candidate biomarker. Here we collated and analysed SERPING1 expression data and subsequently determined C1-INH protein levels in four cohorts of patients with TB. METHODS: SERPING1 expression data were extracted from online deposited datasets. C1-INH protein levels were determined by ELISA in sera from individuals with active TB, LTBI as well as other disease controls in geographically diverse cohorts. FINDINGS: SERPING1 expression was increased in patients with active TB compared to healthy controls (8/11 cohorts), LTBI (13/14 cohorts) and patients with other (non-TB) lung-diseases (7/7 cohorts). Serum levels of C1-INH were significantly increased in The Gambia and Italy in patients with active TB relative to the endemic controls but not in South Africa or Korea. In the largest cohort (n = 50), with samples collected longitudinally, normalization of C1-INH levels following successful TB treatment was observed. This cohort, also showed the most abundant increase in C1-INH, and a positive correlation between C1q and C1-INH levels. Combined presence of increased levels of both C1q and C1-INH had high specificity for active TB (96 %) but only very modest sensitivity 38 % compared to the endemic controls. INTERPRETATION: SERPING1 transcript expression is increased in TB patients, while serum protein levels of C1-INH were increased in half of the cohorts analysed.


Assuntos
Proteína Inibidora do Complemento C1/biossíntese , Proteína Inibidora do Complemento C1/genética , Tuberculose Latente/genética , Tuberculose Latente/imunologia , Tuberculose Pulmonar/genética , Tuberculose Pulmonar/imunologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Biomarcadores/sangue , Estudos de Casos e Controles , Estudos de Coortes , Proteína Inibidora do Complemento C1/metabolismo , Complemento C1q/metabolismo , Feminino , Expressão Gênica , Humanos , Tuberculose Latente/sangue , Estudos Longitudinais , Masculino , Pessoa de Meia-Idade , Tuberculose Pulmonar/sangue , Adulto Jovem
11.
PLoS One ; 15(3): e0229992, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32163462

RESUMO

Recombinant production of IgM antibodies poses a special challenge due to the complex structure of the proteins and their not yet fully elucidated interactions with the immune effector proteins, especially the complement system. In this study, we present transient expression of IgM antibodies (IgM617, IgM012 and IgM012_GL) in HEK cells and compared it to the well-established stable expression system in CHO cells. The presented workflow investigates quality attributes including productivity, polymer distribution, glycosylation, antibody structure and activation of the classical complement pathway. The HEK293E transient expression system is able to generate comparable amounts and polymer distribution as IgM stably produced in CHO. Although the glycan profile generated by HEK293E cells contained a lower degree of sialylation and a higher portion of oligomannose structures, the potency to activate the complement cascade was maintained. Electron microscopy also confirmed the structural integrity of IgM pentamers produced in HEK293E cells, since the conventional star-shaped structure is observed. From our studies, we conclude that the transient expression system provides an attractive alternative for rapid, efficient and high-throughput production of complex IgM antibodies with slightly altered post-translational modifications, but comparable structure and function.


Assuntos
Imunoglobulina M/metabolismo , Animais , Células CHO , Ativação do Complemento , Complemento C1q/química , Complemento C1q/metabolismo , Cricetinae , Cricetulus , Glicosilação , Células HEK293 , Humanos , Imunoglobulina M/química , Imunoglobulina M/genética , Microscopia Eletrônica de Transmissão , Oligossacarídeos/química , Plasmídeos/genética , Plasmídeos/metabolismo , Transfecção
12.
Mol Immunol ; 120: 130-135, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32120180

RESUMO

BACKGROUND AND OBJECTIVES: The complement system plays an important role in the development of acute coronary syndrome (ACS). Complement C1q is an important initial component of the classical complement pathway and closely related to many chronic inflammatory diseases, including atherosclerosis (AS). We aimed to determine whether there was association between serum complement C1q and the severity of coronary stenosis. SUBJECTS AND METHODS: 320 patients who underwent coronary arteriography (CAG) were stratified into non-ACS group (control group, n = 74), unstable angina group (UA group, n = 197) and acute myocardial infarction group (AMI group, n = 49) according to the severity of coronary stenosis and clinical manifestations. The severity of coronary stenosis was represented in Gensini score, and serum complement C1q level was compared using immunity transmission turbidity among three groups. RESULTS: The level of complement C1q in AMI group was lower significantly than control group and UA group (P < 0.05), but there was no correlation between serum complement C1q and Gensini score (ß=-0.086, P = 0.125). In nitrate-taking patients, serum complement C1q had a negative association with Gensini score (r=-0.275, P = 0.001), and in non-smokers, there was also a negative correlation (ß=-0.159, P = 0.036). After calibrating smoking, drinking or statins, the serum complement C1q levels of control group, UA group and AMI group decreased in sequence (P <  0.05). Logistic regression analysis showed that the decreasing of serum complement C1q was an unfavorable factor for acute myocardial infarction (OR=0.984, 95 %CI=0.972∼0.997, P = 0.015) and for ACS (OR=0.984, 95 %CI=0.971∼0.984, P = 0.025) in drinking patients. Regrettably, ROC curve suggested that the accuracy in diagnosing coronary atherosclerotic heart disease by serum complement C1q was low (AUC=0.568, 95 %CI= 0.492-0.644, P = 0.076, sensitivity 73.6 %, specificity 58.1 %). CONCLUSION: Serum complement C1q in ACS patients, in particular AMI patients, showed lower level. This finding suggests further decrease of complement C1q level in ACS patients may be a contributory factor to instability or rupture of atherosclerotic plaques. Combined with other clinical indicators, it can be helpful to predict the risk and severity of coronary stenosis.


Assuntos
Síndrome Coronariana Aguda/sangue , Síndrome Coronariana Aguda/imunologia , Complemento C1q/metabolismo , Síndrome Coronariana Aguda/etiologia , Idoso , Angina Instável/sangue , Angina Instável/complicações , Angina Instável/imunologia , Biomarcadores/sangue , Estudos de Casos e Controles , Complemento C1q/deficiência , Estenose Coronária/sangue , Estenose Coronária/complicações , Estenose Coronária/imunologia , Feminino , Humanos , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Infarto do Miocárdio/sangue , Infarto do Miocárdio/complicações , Infarto do Miocárdio/imunologia , Placa Aterosclerótica/sangue , Placa Aterosclerótica/complicações , Placa Aterosclerótica/imunologia , Curva ROC , Fatores de Risco , Ruptura Espontânea
13.
Proc Natl Acad Sci U S A ; 117(12): 6717-6725, 2020 03 24.
Artigo em Inglês | MEDLINE | ID: mdl-32139604

RESUMO

Most hepatocellular carcinomas (HCCs) develop in patients with chronic hepatitis, which creates a microenvironment for the growth of hepatic progenitor cells (HPCs) at the periportal area and subsequent development of HCCs. We investigated the signal from the inflammatory liver for this pathogenic process in the hepatic conditional ß-catenin knockout mouse model. Senescent ß-catenin-depleted hepatocytes in aged mice create an inflammatory microenvironment that stimulates periportal HPC expansion but arrests differentiation, which predisposes mice to the development of liver tumors. The release of complement C1q from macrophages in the inflammatory niche was identified as the unorthodox signal that activated the ß-catenin pathway in periportal HPCs and was responsible for their expansion and de-differentiation. C1q inhibitors blocked the ß-catenin pathway in both the expanding HPCs and the liver tumors but spared its orthodox pathway in pericentral normal hepatocytes. This mechanism has been validated in human liver specimens from patients with chronic hepatitis. Taken together, these results demonstrate that C1q- mediated activation of ß-catenin pathway in periportal HPCs is a previously unrecognized mechanism for replenishing hepatocytes in the inflammatory liver and, if unchecked, for promoting hepatocarcinogenesis. C1q may become a new target for blocking carcinogenesis in patients with chronic hepatitis.


Assuntos
Carcinoma Hepatocelular/etiologia , Complemento C1q/metabolismo , Hepatite Crônica/complicações , Neoplasias Hepáticas/etiologia , Fígado/patologia , Células-Tronco/patologia , beta Catenina/fisiologia , Animais , Carcinogênese , Carcinoma Hepatocelular/metabolismo , Carcinoma Hepatocelular/patologia , Diferenciação Celular , Senescência Celular , Humanos , Fígado/imunologia , Fígado/metabolismo , Neoplasias Hepáticas/metabolismo , Neoplasias Hepáticas/patologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Camundongos Transgênicos , Transdução de Sinais , Células-Tronco/imunologia , Células-Tronco/metabolismo , Microambiente Tumoral
14.
Vet Microbiol ; 241: 108563, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31928703

RESUMO

Complement component 1, q subcomponent binding protein (C1QBP) is a receptor for the globular heads of C1q and modulates various biological processes including infection, inflammation, autoimmunity, and cancer. In our previous study to identify differentially expressed secretory proteins in Marc-145 cells infected with porcine reproductive and respiratory syndrome virus (PRRSV), mass spectrum data showed that C1QBP was secreted after PRRSV infection. However, the biological significance of secreted C1QBP remains unclear. In this study, we confirmed that PRRSV infection promoted C1QBP secretion in Marc-145 cells and porcine alveolar macrophages (PAMs), the target cells of PRRSV in vivo. Knockdown of endogenous C1QBP decreased PRRSV-induced inflammatory responses. The purified recombinant porcine C1QBP (poC1QBP) had proinflammatory effects. The exogenous addition of poC1QBP significantly enhanced PRRSV-induced inflammatory responses and abolished the inhibitory effects mediated by poC1QBP-knockdown. Taken together, these results demonstrate that PRRSV infection promotes poC1QBP secretion that enhances inflammatory responses.


Assuntos
Complemento C1q/metabolismo , Proteínas Mitocondriais/metabolismo , Síndrome Respiratória e Reprodutiva Suína/metabolismo , Vírus da Síndrome Respiratória e Reprodutiva Suína/fisiologia , Sequência de Aminoácidos , Animais , Western Blotting/veterinária , Linhagem Celular , Chlorocebus aethiops , Clonagem Molecular , Complemento C1q/genética , Citocinas/metabolismo , DNA Complementar/genética , Técnica Indireta de Fluorescência para Anticorpo/veterinária , Regulação Viral da Expressão Gênica , Técnicas de Silenciamento de Genes , Inflamação/metabolismo , Rim/citologia , Rim/virologia , Macrófagos Alveolares/virologia , Síndrome Respiratória e Reprodutiva Suína/patologia , RNA Mensageiro/metabolismo , Reação em Cadeia da Polimerase em Tempo Real/veterinária , Alinhamento de Sequência/veterinária , Suínos
15.
J Neuroinflammation ; 17(1): 8, 2020 Jan 06.
Artigo em Inglês | MEDLINE | ID: mdl-31906973

RESUMO

BACKGROUND: Cognitive impairment in schizophrenia, aging, and Alzheimer's disease is associated with spine and synapse loss from the dorsolateral prefrontal cortex (dlPFC) layer III. Complement cascade signaling is critical in driving spine loss and disease pathogenesis. Complement signaling is initiated by C1q, which tags synapses for elimination. C1q is thought to be expressed predominately by microglia, but its expression in primate dlPFC has never been examined. The current study assayed C1q levels in aging primate dlPFC and rat medial PFC (mPFC) and used immunoelectron microscopy (immunoEM), immunoblotting, and co-immunoprecipitation (co-IP) to reveal the precise anatomical distribution and interactions of C1q. METHODS: Age-related changes in C1q levels in rhesus macaque dlPFC and rat mPFC were examined using immunoblotting. High-spatial resolution immunoEM was used to interrogate the subcellular localization of C1q in aged macaque layer III dlPFC and aged rat layer III mPFC. co-IP techniques quantified protein-protein interactions for C1q and proteins associated with excitatory and inhibitory synapses in macaque dlPFC. RESULTS: C1q levels were markedly increased in the aged macaque dlPFC. Ultrastructural localization found the expected C1q localization in glia, including those ensheathing synapses, but also revealed extensive localization within neurons. C1q was found near synapses, within terminals and in spines, but was also observed in dendrites, often near abnormal mitochondria. Similar analyses in aging rat mPFC corroborated the findings in rhesus macaques. C1q protein increasingly associated with PSD95 with age in macaque, consistent with its synaptic localization as evidenced by EM. CONCLUSIONS: These findings reveal novel, intra-neuronal distribution patterns for C1q in the aging primate cortex, including evidence of C1q in dendrites. They suggest that age-related changes in the dlPFC may increase C1q expression and synaptic tagging for glial phagocytosis, a possible mechanism for age-related degeneration.


Assuntos
Envelhecimento/metabolismo , Complemento C1q/análise , Complemento C1q/metabolismo , Neurônios/metabolismo , Córtex Pré-Frontal/química , Córtex Pré-Frontal/metabolismo , Animais , Macaca mulatta , Neurônios/ultraestrutura , Córtex Pré-Frontal/ultraestrutura , Ratos , Ratos Sprague-Dawley
16.
Clin Exp Immunol ; 200(1): 1-11, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-31853959

RESUMO

Carbamylation is a post-translational modification that can be detected on a range of proteins, including immunoglobulin (Ig)G, in several clinical conditions. Carbamylated IgG (ca-IgG) was reported to lose its capacity to trigger complement activation, but the mechanism remains unclear. Because C1q binds with high affinity to hexameric IgG, we analyzed whether carbamylation of IgG affects binding of C1q, hexamerization and complement-dependent cytotoxicity (CDC). Synovial tissues of rheumatoid arthritis (RA) patients were analyzed for the presence of ca-IgG in vivo. Synovial tissues from RA patients were analyzed for the presence of ca-IgG using mass spectrometry (MS). Monomeric or hexameric antibodies were carbamylated in vitro and quality in solution was controlled. The capacity of ca-IgG to activate complement was analyzed in enzyme-linked immunosorbent (ELISAs) and cellular CDC assays. Using MS, we identified ca-IgG to be present in the joints of RA patients. Using in vitro carbamylated antibodies, we observed that ca-IgG lost its capacity to activate complement in both solid-phase and CDC assays. Mixing ca-IgG with non-modified IgG did not result in effective inhibition of complement activation by ca-IgG. Carbamylation of both monomeric IgG and preformed hexameric IgG greatly impaired the capacity to trigger complement activation. Furthermore, upon carbamylation, the preformed hexameric IgG dissociated into monomeric IgG in solution, indicating that carbamylation influences both hexamerization and C1q binding. In conclusion, ca-IgG can be detected in vivo and has a strongly reduced capacity to activate complement which is, in part, mediated through a reduced ability to form hexamers.


Assuntos
Artrite Reumatoide/imunologia , Ativação do Complemento/imunologia , Complemento C1q/imunologia , Imunoglobulina G/imunologia , Idoso , Sequência de Aminoácidos , Anticorpos Monoclonais/imunologia , Anticorpos Monoclonais/metabolismo , Artrite Reumatoide/metabolismo , Linhagem Celular Tumoral , Complemento C1q/metabolismo , Testes Imunológicos de Citotoxicidade , Ensaio de Imunoadsorção Enzimática , Humanos , Imunoglobulina G/química , Imunoglobulina G/metabolismo , Masculino , Espectrometria de Massas , Pessoa de Meia-Idade , Carbamilação de Proteínas/imunologia , Multimerização Proteica/imunologia , Líquido Sinovial/imunologia , Líquido Sinovial/metabolismo , Membrana Sinovial/imunologia , Membrana Sinovial/metabolismo
17.
J Neurosci ; 40(4): 769-783, 2020 01 22.
Artigo em Inglês | MEDLINE | ID: mdl-31801811

RESUMO

C1q, the initiator of the classical complement cascade, mediates synapse elimination in the postnatal mouse dorsolateral geniculate nucleus of the thalamus and sensorimotor cortex. Here, we asked whether C1q plays a role in experience-dependent synaptic refinement in the visual system at later stages of development. The binocular zone of primary visual cortex (V1b) undergoes spine loss and changes in neuronal responsiveness following the closure of one eye during a defined critical period [a process referred to as ocular dominance plasticity (ODP)]. We therefore hypothesized that ODP would be impaired in the absence of C1q, and that V1b development would also be abnormal without C1q-mediated synapse elimination. However, when we examined several features of V1b development in mice lacking C1q, we found that the densities of most spine populations on basal and proximal apical dendrites, as well as firing rates and ocular dominance, were normal. C1q was only transiently required for the development of spines on apical, but not basal, secondary dendrites. Dendritic morphologies were also unaffected. Although we did not observe the previously described spine loss during ODP in either genotype, our results reveal that the animals lacking C1q had normal shifts in neuronal responsiveness following eye closure. Experiments were performed in both male and female mice. These results suggest that the development and plasticity of the mouse V1b is grossly normal in the absence of C1q.SIGNIFICANCE STATEMENT These findings illustrate that the development and experience-dependent plasticity of V1b is mostly normal in the absence of C1q, even though C1q has previously been shown to be required for developmental synapse elimination in the mouse visual thalamus as well as sensorimotor cortex. The V1b phenotypes in mice lacking C1q are more similar to the mild defects previously observed in the hippocampus of these mice, emphasizing that the contribution of C1q to synapse elimination appears to be dependent on context.


Assuntos
Complemento C1q/metabolismo , Dominância Ocular/fisiologia , Plasticidade Neuronal/fisiologia , Neurônios/metabolismo , Córtex Visual/metabolismo , Animais , Complemento C1q/genética , Dendritos/metabolismo , Espinhas Dendríticas/metabolismo , Camundongos , Camundongos Knockout , Sinapses/metabolismo
18.
Rev Med Chil ; 148(5): 702-706, 2020 May.
Artigo em Espanhol | MEDLINE | ID: mdl-33399765

RESUMO

C1q nephropathy is a rare glomerulopathy characterized by mesangial deposition of the complement component C1q. These deposits can be isolated or associated with immunoglobulins or complement fractions, which are observed by immunofluorescence or immunohistochemical microscopy. In ultramicroscopy, dense mesangial deposits and alterations of the podocyte are observed. Clinically it presents as a nephrotic syndrome (NS) or by alterations of the urinalysis such as proteinuria and/or hematuria in children and young adults. In light microscopy, it is expressed with a morphological pattern of minimal change disease (MCD), mesangial proliferative glomerulonephritis or focal segmental glomerulosclerosis (FSGS). The NS during its evolution usually evolve in steroid resistance or steroid dependency, often requiring the association of immunosuppressants to obtain remission. We report a 14 years old male with a history of NS and its evolution under various treatments during a 12-year follow-up.


Assuntos
Complemento C1q , Glomerulonefrite , Adolescente , Complemento C1q/metabolismo , Glomerulonefrite/diagnóstico , Humanos , Masculino
19.
Pharm Res ; 37(1): 10, 2019 Dec 23.
Artigo em Inglês | MEDLINE | ID: mdl-31872347

RESUMO

PURPOSE: As nanoparticles (NPs) are intravenously entering the bloodstream, proteins in the plasma can recognize and bind them to form a protein corona that affects how NPs are perceived by biological systems. The complement is an essential part of the innate immunity that contributes to non-specific host defense. How complement recognizes NPs has not been elucidated. Here, we developed a proteomics and biochemical approach to understand the applied risk of activated complement by NPs. METHODS: Complement proteins absorbed on Hydroxyapatite Nanoparticles (HAP-NPs) and Silicon dioxide Nanoparticles (SiO2-NPs) were analyzed by proteomics with LC-MS. The effect of complement activation was studied by iC3b/Sc5b-9/C3a/C4a/C5a with ELISA. An inhibitory model was established via EDTA and EGTA to confirm the selective pathway activation of both NPs. Finally, the regulation of complement by NPs was analyzed by western blot. RESULTS: The results indicate that HAP-NPs start the activation of the complement through the classical pathway because of the absorption of C1q and the release of C1r/C1s. Meanwhile, the soluble regulatory molecules such as CFI, C4bp, and CFH tried to resist the complement system activation by the cleavage of C3 convertase. In contrast, SiO2-NPs can activate the alternative pathway of the complement through the absorption of CFD and CFB. CONCLUSION: It was clarified that HAP-NPs and SiO2-NPs activate complement through different mechanisms. These studies provide a scientific basis for the design and modification of nano-drug carriers for delaying their recognition and clearance by the mononuclear phagocytic system and simultaneously reducing the immunotoxicity of NPs. The understanding of protein corona is conducive to innovation in the field of "immune-safe-by-design" nanomedicines.


Assuntos
Complemento C1q/metabolismo , Portadores de Fármacos/química , Nanopartículas/química , Coroa de Proteína/química , Coroa de Proteína/metabolismo , Ativação do Complemento/efeitos dos fármacos , Proteínas do Sistema Complemento/metabolismo , Composição de Medicamentos/métodos , Liberação Controlada de Fármacos , Durapatita/química , Humanos , Proteômica , Soro/metabolismo , Transdução de Sinais , Dióxido de Silício/química , Manejo de Espécimes , Espectrometria de Massas em Tandem/métodos
20.
Front Immunol ; 10: 2712, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31824501

RESUMO

Complement C1q, the initiation molecule of the classical pathway, exerts various immunomodulatory functions independent of complement activation. Non-classical functions of C1q include the clearance of apoptotic cells and cholesterol crystals (CC), as well as the modulation of cytokine secretion by immune cells such as macrophages. Moreover, C1q has been shown to act as a binding partner for von Willebrand factor (vWF), initiation molecule of primary hemostasis. However, the consequences of this C1q-vWF interaction on the phagocytosis of CC by macrophages has remained elusive until now. Here, we used CC-C1q-vWF complexes to study immunological effects on human monocyte-derived macrophages (HMDMs). HMDMs were investigated by analyzing surface receptor expression, phagocytosis of CC complexes, cytokine secretion, and caspase-1 activity. We found that vWF only bound to CC in a C1q-dependent manner. Exposure of macrophages to CC-C1q-vWF complexes resulted in an upregulated expression of phagocytosis-mediating receptors MerTK, LRP-1, and SR-A1 as well as CD14, LAIR1, and PD-L1 when compared to CC-C1q without vWF, whereas phagocytosis of CC-C1q complexes was hampered in the presence of vWF. In addition, we observed a diminished caspase-1 activation and subsequent reduction in pro-inflammatory IL-1ß cytokine secretion, IL-1ß/IL-1RA ratio and IL-1α/IL-1RA ratio. In conclusion, our results demonstrate that vWF binding to C1q substantially modulates the effects of C1q on HMDMs. In this way, the C1q-vWF interaction might be beneficial in dampening inflammation, e.g., in the context of atherosclerosis.


Assuntos
Colesterol/metabolismo , Complemento C1q/imunologia , Complemento C1q/metabolismo , Macrófagos/imunologia , Macrófagos/metabolismo , Fagocitose/imunologia , Fator de von Willebrand/metabolismo , Biomarcadores , Caspase 1/metabolismo , Quimiocinas CC/metabolismo , Colesterol/química , Citocinas/metabolismo , Humanos , Imunidade Inata
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