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1.
Front Immunol ; 13: 861545, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35669782

RESUMO

Cutaneous melanoma is one of the most aggressive human malignancies and shows increasing incidence. Mast cells (MCs), long-lived tissue-resident cells that are particularly abundant in human skin where they regulate both innate and adaptive immunity, are associated with melanoma stroma (MAMCs). Thus, MAMCs could impact melanoma development, progression, and metastasis by secreting proteases, pro-angiogenic factors, and both pro-inflammatory and immuno-inhibitory mediators. To interrogate the as-yet poorly characterized role of human MAMCs, we have purified MCs from melanoma skin biopsies and performed RNA-seq analysis. Here, we demonstrate that MAMCs display a unique transcriptome signature defined by the downregulation of the FcεRI signaling pathway, a distinct expression pattern of proteases and pro-angiogenic factors, and a profound upregulation of complement component C3. Furthermore, in melanoma tissue, we observe a significantly increased number of C3+ MCs in stage IV melanoma. Moreover, in patients, C3 expression significantly correlates with the MC-specific marker TPSAB1, and the high expression of both markers is linked with poorer melanoma survival. In vitro, we show that melanoma cell supernatants and tumor microenvironment (TME) mediators such as TGF-ß, IL-33, and IL-1ß induce some of the changes found in MAMCs and significantly modulate C3 expression and activity in MCs. Taken together, these data suggest that melanoma-secreted cytokines such as TGF-ß and IL-1ß contribute to the melanoma microenvironment by upregulating C3 expression in MAMCs, thus inducing an MC phenotype switch that negatively impacts melanoma prognosis.


Assuntos
Melanoma , Neoplasias Cutâneas , Complemento C3/metabolismo , Humanos , Mastócitos , Melanoma/patologia , Peptídeo Hidrolases/metabolismo , Neoplasias Cutâneas/patologia , Fator de Crescimento Transformador beta/metabolismo , Microambiente Tumoral/genética , Regulação para Cima
2.
Cell Mol Life Sci ; 79(6): 291, 2022 May 11.
Artigo em Inglês | MEDLINE | ID: mdl-35546365

RESUMO

Complement C3 was originally regarded as a serum effector protein, although recent data has emerged suggesting that intracellular C3 can also regulate basic cellular processes. Despite the growing interest in intracellular C3 functions, the mechanism behind its generation has not been demonstrated. In this study we show that C3 can be expressed from an alternative translational start site, resulting in C3 lacking the signal peptide, which is therefore translated in the cytosol. In contrast to the secreted form, alternatively translated cytosolic C3 is not glycosylated, is present mainly in a reduced state, and is turned over by the ubiquitin-proteasome system. C3 can also be retrotranslocated from the endoplasmic reticulum into the cytosol, structurally resembling secreted C3. Finally, we demonstrate that intracellular cytosolic C3 can opsonize invasive Staphylococcus aureus within epithelial cell, slowing vacuolar escape as well as impacting bacterial survival on subsequent exposure to phagocytes. Our work therefore reveals the existence and origin of intracellular, cytosolic C3, and demonstrates functions for cytosolic C3 in intracellular detection of cytoinvasive pathogens.


Assuntos
Complemento C3 , Complexo de Endopeptidases do Proteassoma , Bactérias/metabolismo , Complemento C3/metabolismo , Citosol/metabolismo , Retículo Endoplasmático/metabolismo , Complexo de Endopeptidases do Proteassoma/metabolismo
3.
Front Immunol ; 13: 891994, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35592325

RESUMO

Complement components have a reputation to be very labile. One of the reasons for this is the spontaneous hydrolysis of the internal thioester that is found in both C3 and C4 (but not in C5). Despite the fact that ≈20,000 papers have been published on human C3 there is still no reliable method to store the protein without generating C3(H2O), a fact that may have affected studies of the conformation and function of C3, including recent studies on intracellular C3(H2O). The aim of this work was to define the conditions for storage of native C3 and to introduce a robust method that makes C3 almost resistant to the generation of C3(H2O). Here, we precipitated native C3 at the isoelectric point in low ionic strength buffer before freezing the protein at -80°C. The formation of C3(H2O) was determined using cation exchange chromatography and the hemolytic activity of the different C3 preparations was determined using a hemolytic assay for the classical pathway. We show that freezing native C3 in the precipitated form is the best method to avoid loss of function and generation of C3(H2O). By contrast, the most efficient way to consistently generate C3(H2O) was to incubate native C3 in a buffer at pH 11.0. We conclude that we have defined the optimal storage conditions for storing and maintaining the function of native C3 without generating C3(H2O) and also the conditions for consistently generating C3(H2O).


Assuntos
Complemento C3 , Hemólise , Complemento C3/metabolismo , Humanos , Hidrólise
4.
J Am Soc Nephrol ; 33(6): 1137-1153, 2022 06.
Artigo em Inglês | MEDLINE | ID: mdl-35545301

RESUMO

BACKGROUND: C3 glomerulopathy (C3G) is a heterogeneous group of chronic renal diseases characterized predominantly by glomerular C3 deposition and complement dysregulation. Mutations in factor H-related (FHR) proteins resulting in duplicated dimerization domains are prototypical of C3G, although the underlying pathogenic mechanism is unclear. METHODS: Using in vitro and in vivo assays, we performed extensive characterization of an FHR-1 mutant with a duplicated dimerization domain. To assess the FHR-1 mutant's association with disease susceptibility and renal prognosis, we also analyzed CFHR1 copy number variations and FHR-1 plasma levels in two Spanish C3G cohorts and in a control population. RESULTS: Duplication of the dimerization domain conferred FHR-1 with an increased capacity to interact with C3-opsonized surfaces, which resulted in an excessive activation of the alternative pathway. This activation does not involve C3b binding competition with factor H. These findings support a scenario in which mutant FHR-1 binds to C3-activated fragments and recruits native C3 and C3b; this leads to formation of alternative pathway C3 convertases, which increases deposition of C3b molecules, overcoming FH regulation. This suggests that a balanced FHR-1/FH ratio is crucial to control complement amplification on opsonized surfaces. Consistent with this conceptual framework, we show that the genetic deficiency of FHR-1 or decreased FHR-1 in plasma confers protection against developing C3G and associates with better renal outcome. CONCLUSIONS: Our findings explain how FHR-1 mutants with duplicated dimerization domains result in predisposition to C3G. They also provide a pathogenic mechanism that may be shared by other diseases, such as IgA nephropathy or age-related macular degeneration, and identify FHR-1 as a potential novel therapeutic target in C3G.


Assuntos
Proteínas Inativadoras do Complemento C3b , Glomerulonefrite por IGA , Proteínas Sanguíneas , Complemento C3/genética , Complemento C3/metabolismo , Proteínas Inativadoras do Complemento C3b/genética , Proteínas Inativadoras do Complemento C3b/metabolismo , Fator H do Complemento/genética , Variações do Número de Cópias de DNA , Suscetibilidade a Doenças , Glomerulonefrite por IGA/genética , Glomerulonefrite por IGA/metabolismo , Humanos , Prognóstico
5.
Immunobiology ; 227(3): 152225, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35567980

RESUMO

Several disorders associated with the total or partial absence of components of the human complement system are known. Deficiencies of classical pathway (CP) components are generally linked to systemic lupus erythematosus (SLE) or SLE-like syndromes. However, only approximately one-third of patients who lack C2 show mild symptoms of SLE. The relatively high frequency of homozygous C2 deficiency without or with minor disease manifestation suggests that there might be a compensatory mechanism which allows the activation of the CP of complement without the absolute requirement of C2. In this study we show that factor B (FB), the C2 homologue of the alternative pathway (AP) of complement, can substitute for C2. This was confirmed by using C4b as immobilised ligand and FB as analyte in Surface Plasmon Resonance (BIACORE). C2 binding to the immobilised C3b-like molecule C3(CH3NH2) was not seen. The estimated binding constant for C4bB complex formation was 2.00 * 10-5 [M]. We were further able to demonstrate that C4b supports the cleavage of Factor B by Factor D. Finally, cleavage of 125I-C3 by C4bBb was evaluated and gave strong evidence that the "hybrid" convertase C4bBb can cleave and activate C3 in vitro. Cleavage activity is very low, but consistent with some of the "C2-bypass" observations of others.


Assuntos
Complemento C4 , Lúpus Eritematoso Sistêmico , Ativação do Complemento , Complemento C2/metabolismo , Complemento C3/metabolismo , Convertases de Complemento C3-C5/metabolismo , Complemento C3b , Fator B do Complemento , Via Clássica do Complemento , Humanos
6.
Front Immunol ; 13: 840861, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35359984

RESUMO

Complement proteins emerged early in evolution but outside the vertebrate clade they are poorly characterized. An evolutionary model of C3 family members revealed that in contrast to vertebrates the evolutionary trajectory of C3-like genes in cnidarian, protostomes and invertebrate deuterostomes was highly divergent due to independent lineage and species-specific duplications. The deduced C3-like and vertebrate C3, C4 and C5 proteins had low sequence conservation, but extraordinarily high structural conservation and 2-chain and 3-chain protein isoforms repeatedly emerged. Functional characterization of three C3-like isoforms in a bivalve representative revealed that in common with vertebrates complement proteins they were cleaved into two subunits, b and a, and the latter regulated inflammation-related genes, chemotaxis and phagocytosis. Changes within the thioester bond cleavage sites and the a-subunit protein (ANATO domain) explained the functional differentiation of bivalve C3-like. The emergence of domain-related functions early during evolution explains the overlapping functions of bivalve C3-like and vertebrate C3, C4 and C5, despite low sequence conservation and indicates that evolutionary pressure acted to conserve protein domain organization rather than the primary sequence.


Assuntos
Complemento C3 , Invertebrados , Sequência de Aminoácidos , Animais , Complemento C3/metabolismo , Filogenia , Especificidade da Espécie
7.
Cell Prolif ; 55(5): e13226, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35403306

RESUMO

Triple-negative breast cancer (TNBC) is the most aggressive subtype of breast cancer. However, the treatment regimens for TNBC are limited. Chromosome segregation 1-like (CSE1L), also called cellular apoptosis susceptibility protein (CAS), is highly expressed in breast cancer and plays a crucial role in the progression of various tumours. However, the involvement of CAS in TNBC remains elusive. In this study, we showed that the expression of CAS was higher in TNBC samples than in non-TNBC samples in the Gene Expression Omnibus database. Knockdown of CAS inhibited MDA-MB-231 cell growth, migration and invasion. Further RNA-seq analysis revealed that complement pathway activity was significantly elevated. Of note, complement component 3 (C3), the key molecule in the complement pathway, was significantly upregulated, and the expression of C3 was negatively correlated with that of CAS in breast cancer. Lower C3 expression was related to poor prognosis. Interestingly, the expression level of C3 was positively correlated with the infiltration of multiple immune cells. Taken together, our findings suggest that CAS participates in the development of TNBC through C3-mediated immune cell suppression and might constitute a potential therapeutic target for TNBC.


Assuntos
Complemento C3/metabolismo , Neoplasias de Mama Triplo Negativas , Mama/patologia , Linhagem Celular Tumoral , Movimento Celular , Proliferação de Células , Proteína de Suscetibilidade a Apoptose Celular/genética , Regulação Neoplásica da Expressão Gênica , Humanos , Neoplasias de Mama Triplo Negativas/patologia
8.
Food Chem Toxicol ; 164: 113017, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35452770

RESUMO

Kaempferol is a natural antioxidant present in vegetables and fruits used in human nutrition. In previous work, we showed that intraperitoneal (i.p.) kaempferol administration strongly protects against striatum neurodegeneration induced by i.p. injections of 3-nitropropionic acid (NPA), an animal model of Huntington's disease. Recently, we have shown that reactive A1 astrocytes generation is an early event in the neurodegeneration induced by NPA i.p. injections. In the present work, we have experimentally evaluated the hypothesis that kaempferol protects both against the activation of complement C3 protein and the generation of reactive A1 astrocytes in rat brain striatum and hippocampus. To this end, we have administered NPA and kaempferol i.p. injections to adult Wistar rats following the protocol described in previous work. Kaempferol administration prevents proteolytic activation of complement C3 protein and generation of reactive A1 astrocytes NPA-induced in the striatum and hippocampus. Also, it blocked the NPA-induced increase of NF-κB expression and enhanced secretion of cytokines IL-1α, TNFα, and C1q, which have been linked to the generation of reactive A1 astrocytes. In addition, kaempferol administration prevented the enhanced production of amyloid ß peptides in the striatum and hippocampus, a novel finding in NPA-induced brain degeneration found in this work.


Assuntos
Complemento C3 , Quempferóis , Peptídeos beta-Amiloides/metabolismo , Animais , Astrócitos/metabolismo , Complemento C3/metabolismo , Corpo Estriado/metabolismo , Quempferóis/metabolismo , Quempferóis/farmacologia , Nitrocompostos/toxicidade , Propionatos/farmacologia , Ratos , Ratos Wistar
9.
Front Immunol ; 13: 813173, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35281048

RESUMO

In the complement system, C3 is a central component in complement activation, immune defense and immune regulation. In all pathways of complement activation, the pivotal step is conversion of the component C3 to C3b and C3a, which is responsible to eliminate the pathogen and opsonization. In this study, we examined the immunological properties of C3 and its activated fragment C3a from Japanese flounder (Paralichthys olivaceus) (PoC3 and PoC3a), a teleost species with important economic value. PoC3 is composed of 1655 amino acid residues, contains the six domains and highly conserved GCGEQ sequence of the C3 family. We found that PoC3 expression occurred in nine different tissues and was upregulated by bacterial challenge. In serum, PoC3 was able to bind to a broad-spectrum of bacteria, and purified native PoC3 could directly kill specific pathogen. When PoC3 expression in Japanese flounder was knocked down by siRNA, serum complement activity was significantly decreased, and bacterial replication in fish tissues was significantly increased. Recombinant PoC3a (rPoC3a) exhibited apparent binding capacities to bacteria and Japanese flounder peripheral blood leukocytes (PBL) and induce chemotaxis of PBL. Japanese flounder administered rPoC3a exhibited enhanced resistance against bacterial infection. Taken together, these results indicate that PoC3 is likely a key factor of complement activation, and PoC3 and PoC3a are required for optimal defense against bacterial infection in teleost.


Assuntos
Infecções Bacterianas , Doenças dos Peixes , Linguado , Animais , Bactérias , Ativação do Complemento , Complemento C3/genética , Complemento C3/metabolismo
10.
Biomolecules ; 12(3)2022 03 11.
Artigo em Inglês | MEDLINE | ID: mdl-35327625

RESUMO

Uncontrolled complement activation contributes to multiple immune pathologies. Although synthetic compstatin derivatives targeting C3 and C3b are robust inhibitors of complement activation, their physicochemical and molecular properties may limit access to specific organs, development of bifunctional moieties, and therapeutic applications requiring transgenic expression. Complement-targeting therapeutics containing only natural amino acids could enable multifunctional pharmacology, gene therapies, and targeted delivery for underserved diseases. A Nanofitin library of hyperthermophilic protein scaffolds was screened using ribosome display for C3/C3b-targeting clones mimicking compstatin pharmacology. APL-1030, a recombinant 64-residue Nanofitin, emerged as the lead candidate. APL-1030 is thermostable, binds C3 (KD, 1.59 nM) and C3b (KD, 1.11 nM), and inhibits complement activation via classical (IC50 = 110.8 nM) and alternative (IC50 = 291.3 nM) pathways in Wieslab assays. Pharmacologic activity (determined by alternative pathway inhibition) was limited to primate species of tested sera. C3b-binding sites of APL-1030 and compstatin were shown to overlap by X-ray crystallography of C3b-bound APL-1030. APL-1030 is a novel, high-affinity inhibitor of primate C3-mediated complement activation developed from natural amino acids on the hyperthermophilic Nanofitin platform. Its properties may support novel drug candidates, enabling bifunctional moieties, gene therapy, and tissue-targeted C3 pharmacologics for diseases with high unmet need.


Assuntos
Ativação do Complemento , Complemento C3 , Aminoácidos , Animais , Sítios de Ligação , Complemento C3/metabolismo , Cristalografia por Raios X
11.
Front Immunol ; 13: 781273, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35250972

RESUMO

Complement C3 plays a prominent role in inflammatory processes, and its increase exacerbates ischemia reperfusion injury (IRI)-induced acute kidney injury (AKI). Infiltrated neutrophils can be stimulated to form neutrophil extracellular traps (NETs), leading to renal injury. However, the relationship between the increase of C3 and the release of NETs in AKI was not clear. Here we found that IRI in the mouse kidney leads to increased neutrophils infiltration and NET formation. Furthermore, neutrophils depletion by anti-Ly6G IgG (1A8) did not reduce C3 activation but reduced kidney injury and inflammation, indicating a link between neutrophils infiltration and renal tissue damage. Pretreatment with 1A8 suppressed ischemia-induced NET formation, proving that extracellular traps (ETs) in renal tissue were mainly derived from neutrophils. Renal ischemia injury also leads to increased expression of C3. Moreover, C3 KO mice (C3 KO) with IRI exhibited attenuated kidney damage and decreased neutrophils and NETs. In vitro, C3a primed neutrophils to form NETs, reflected by amorphous extracellular DNA structures that colocalized with CitH3 and MPO. These data reveal that C3 deficiency can ameliorate AKI by reducing the infiltration of neutrophils and the formation of NETs. Targeting C3 activation may be a new therapeutic strategy for alleviating the necroinflammation of NETs in AKI.


Assuntos
Injúria Renal Aguda , Complemento C3 , Armadilhas Extracelulares , Traumatismo por Reperfusão , Injúria Renal Aguda/etiologia , Injúria Renal Aguda/metabolismo , Animais , Complemento C3/genética , Complemento C3/metabolismo , Modelos Animais de Doenças , Armadilhas Extracelulares/genética , Armadilhas Extracelulares/metabolismo , Feminino , Isquemia/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Traumatismo por Reperfusão/metabolismo
12.
J Immunol ; 208(7): 1772-1781, 2022 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-35277417

RESUMO

Alternative pathway complement dysregulation with abnormal glomerular C3 deposits and glomerular damage is a key mechanism of pathology in C3 glomerulopathy (C3G). No disease-specific treatments are currently available for C3G. Therapeutics inhibiting complement are emerging as a potential strategy for the treatment of C3G. In this study, we investigated the effects of N-acetylgalactosamine (GalNAc)-conjugated small interfering RNA (siRNA) targeting the C3 component of complement that inhibits liver C3 expression in the C3G model of mice with heterozygous deficiency of factor H (Cfh +/- mice). We showed a duration of action for GalNAc-conjugated C3 siRNA in reducing the liver C3 gene expression in Cfh +/- mice that were dosed s.c. once a month for up to 7 mo. C3 siRNA limited fluid-phase alternative pathway activation, reducing circulating C3 fragmentation and activation of factor B. Treatment with GalNAc-conjugated C3 siRNA reduced glomerular C3d deposits in Cfh +/- mice to levels similar to those of wild-type mice. Ultrastructural analysis further revealed the efficacy of the C3 siRNA in slowing the formation of mesangial and subendothelial electron-dense deposits. The present data indicate that RNA interference-mediated C3 silencing in the liver may be a relevant therapeutic strategy for treating patients with C3G associated with the haploinsufficiency of complement factor H.


Assuntos
Glomerulonefrite Membranoproliferativa , Nefropatias , Animais , Complemento C3/genética , Complemento C3/metabolismo , Fator B do Complemento/metabolismo , Fator H do Complemento/genética , Via Alternativa do Complemento/genética , Glomerulonefrite Membranoproliferativa/patologia , Humanos , Camundongos , RNA Interferente Pequeno/genética
13.
Anticancer Res ; 42(3): 1207-1215, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-35220210

RESUMO

BACKGROUND: We aimed to clarify the role of complement C3a and its receptor C3aR in progression of pancreatic ductal adenocarcinoma (PDAC). MATERIALS AND METHODS: We evaluated the serum levels of C3 and C3a in patients with PDAC. C3aR expression in tissue was assessed using a tissue microarray. To confirm the protumoral effects of C3a in PDAC, we conducted in vitro experiments using PDAC cell lines (Panc-1 and MiaPaca-2) that exhibit high C3aR expression. RESULTS: Serum levels of both C3 and C3a were higher in 26 patients with PDAC than in 28 nontumor-bearing controls. In the tissue microarray, we observed increased expression of C3aR in PDAC cells, especially in cases with metastatic lesions. In vitro experiments showed that C3a facilitated tumor cell proliferation, migration and invasion by activating the extracellular-regulated kinase signaling pathway and inducing epithelial-to-mesenchymal transition. Inhibition of the C3a-C3aR axis by pharmacological blockade and short-hairpin RNA-mediated knockdown of C3aR alleviated its protumoral effect. CONCLUSION: These findings provide a new approach for the development of treatments targeting the C3a-C3aR axis.


Assuntos
Carcinoma Ductal Pancreático/enzimologia , Complemento C3/metabolismo , Transição Epitelial-Mesenquimal , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Neoplasias Pancreáticas/enzimologia , Receptores de Complemento/metabolismo , Idoso , Idoso de 80 Anos ou mais , Arginina/análogos & derivados , Arginina/farmacologia , Compostos Benzidrílicos/farmacologia , Carcinoma Ductal Pancreático/genética , Carcinoma Ductal Pancreático/patologia , Linhagem Celular Tumoral , Movimento Celular , Proliferação de Células , Inativadores do Complemento/farmacologia , Ativação Enzimática , Transição Epitelial-Mesenquimal/efeitos dos fármacos , Feminino , Regulação Neoplásica da Expressão Gênica , Humanos , Masculino , Pessoa de Meia-Idade , Invasividade Neoplásica , Neoplasias Pancreáticas/genética , Neoplasias Pancreáticas/patologia , Receptores de Complemento/antagonistas & inibidores , Receptores de Complemento/genética , Transdução de Sinais
14.
Sci Rep ; 12(1): 1700, 2022 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-35105928

RESUMO

To determine whether complement component 3 (C3) deficiency affects its receptor downstream-mediated inflammatory response, the current study was undertaken to measure alterations in the inducible nitric oxide synthase (iNOS)­mediated cyclooxygenase­2 (COX­2) induction pathway, inflammasome pathway, nuclear factor-κB (NF-κB) activation, and inflammatory cytokine expressions in the mid colon of C3 knockout (KO) mice. Significant enhancement was observed in expressions of key components of the iNOS­mediated COX­2 induction pathway, and in the phosphorylation of mitogen­activated protein (MAP) kinase members. A similar pattern of increase was also observed in the expression levels of inflammasome proteins in C3 KO mice. Moreover, compared to WT mice, C3 KO mice showed remarkably enhanced phosphorylation of NF-κB and Inhibitor of κB-α (IκB-α), which was reflected in entirety as increased expressions of Tumor necrosis factor (TNF), IL-6 and IL-1α. However, the levels of E-cadherin, tight junction channels and ion channels expressions were lower in the C3 KO mice, although myeloperoxidase (MPO) activity for neutrophils was slightly increased. Taken together, results of the current study indicate that C3 deficiency promotes inflammatory responses in the mid colon of C3 KO mice through activation of the iNOS­mediated COX­2 induction pathway, Apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC)-inflammasome pathway and NF-κB signaling pathway, and the enhancement of inflammatory cytokine expressions.


Assuntos
Proteínas Adaptadoras de Sinalização CARD/metabolismo , Colite/metabolismo , Complemento C3/metabolismo , Ciclo-Oxigenase 2/metabolismo , Citocinas/metabolismo , Inflamassomos/metabolismo , NF-kappa B/metabolismo , Óxido Nítrico Sintase Tipo II/metabolismo , Transdução de Sinais/genética , Animais , Apoptose/genética , Colite/genética , Complemento C3/genética , Técnicas de Inativação de Genes/métodos , Camundongos , Camundongos Knockout , Fosforilação/genética
15.
Sci Rep ; 12(1): 1654, 2022 01 31.
Artigo em Inglês | MEDLINE | ID: mdl-35102298

RESUMO

Burn injuries elicit a unique and dynamic stress response which can lead to burn injury progression. Though neutrophils represent crucial players in the burn-induced immunological events, the dynamic secretion pattern and systemic levels of neutrophil-derived factors have not been investigated in detail so far. Serum levels of neutrophil elastase (NE), myeloperoxidase (MPO), citrullinated histone H3 (CitH3), and complement factor C3a were quantified in burn victims over 4 weeks post injury. Furthermore, the potential association with mortality, degree of burn injury, and inhalation trauma was evaluated. In addition, leukocyte, platelet, neutrophil, and lymphocyte counts were assessed. Lastly, we analyzed the association of neutrophil-derived factors with clinical severity scoring systems. Serum levels of NE, MPO, CitH3, and C3a were remarkably elevated in burn victims compared to healthy controls. Leukocyte and neutrophil counts were significantly increased on admission day and day 1, while relative lymphocytes were decreased in the first 7 days post burn trauma. Though neutrophil-derived factors did not predict mortality, patients suffering from 3rd degree burn injuries displayed increased CitH3 and NE levels. Accordingly, CitH3 and NE were elevated in cases with higher abbreviated burn severity indices (ABSI). Taken together, our data suggest a role for neutrophil activation and NETosis in burn injuries and burn injury progression. Targeting exacerbated neutrophil activation might represent a new therapeutic option for severe cases of burn injury.


Assuntos
Queimaduras/imunologia , Ativação de Neutrófilo , Neutrófilos/imunologia , Adulto , Idoso , Biomarcadores/sangue , Queimaduras/sangue , Queimaduras/diagnóstico , Queimaduras/mortalidade , Estudos de Casos e Controles , Citrulinação , Complemento C3/metabolismo , Feminino , Histonas/sangue , Humanos , Contagem de Leucócitos , Elastase de Leucócito/sangue , Masculino , Pessoa de Meia-Idade , Neutrófilos/metabolismo , Peroxidase/sangue , Valor Preditivo dos Testes , Prognóstico , Processamento de Proteína Pós-Traducional , Índice de Gravidade de Doença , Fatores de Tempo , Adulto Jovem
16.
Ann Rheum Dis ; 81(5): 632-643, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35115332

RESUMO

OBJECTIVES: The goals of these studies were to elucidate the inter-relationships of specific anti-nuclear antibody (ANA), complement, and the interferon gene signature (IGS) in the pathogenesis of systemic lupus erythematosus (SLE). METHODS: Data from the Illuminate trials were analysed for antibodies to dsDNA as well as RNA-binding proteins (RBP), levels of C3, C4 and various IGS. Statistical hypothesis testing, linear regression analyses and classification and regression trees analysis were employed to assess relationships between the laboratory features of SLE. RESULTS: Inter-relationships of ANAs, complement and the IGS differed between patients of African Ancestry (AA) and European Ancestry (EA); anti-RNP and multiple autoantibodies were more common in AA patients and, although both related to the presence of the IGS, relationships between autoantibodies and complement differed. Whereas, anti-dsDNA had an inverse relationship to C3 and C4, levels of anti-RNP were not related to these markers. The IGS was only correlated with anti-dsDNA in EA SLE and complement was more correlated to the IGS in AA SLE. Finally, autoantibodies occurred in the presence and absence of the IGS, whereas the IGS was infrequent in anti-dsDNA/anti-RBP-negative SLE patients. CONCLUSION: There is a complex relationship between autoantibodies and the IGS, with anti-RNP associated in AA and both anti-dsDNA and RNP associated in EA. Moreover, there was a difference in the relationship between anti-dsDNA, but not anti-RBP, with complement levels. The lack of a relationship of anti-RNP with C3 and C4 suggests that anti-RNP immune complexes (ICs) may drive the IGS without complement fixation, whereas anti-dsDNA ICs involve complement consumption.


Assuntos
Complemento C3 , Complemento C4 , Interferons , Lúpus Eritematoso Sistêmico , Anticorpos Antinucleares/imunologia , Complexo Antígeno-Anticorpo , Antivirais , Autoanticorpos/imunologia , Complemento C3/imunologia , Complemento C3/metabolismo , Complemento C4/imunologia , Complemento C4/metabolismo , DNA , Humanos , Interferons/imunologia , Lúpus Eritematoso Sistêmico/genética , Lúpus Eritematoso Sistêmico/imunologia , Lúpus Eritematoso Sistêmico/metabolismo
17.
Science ; 375(6581): eabf7470, 2022 02 11.
Artigo em Inglês | MEDLINE | ID: mdl-35143312

RESUMO

Marginal zone (MZ) B cells produce broad-spectrum antibodies that protect against infection early in life. In some instances, antibody production requires MZ B cells to display pathogen antigens bound to major histocompatibility complex class II (MHC II) molecules to T cells. We describe the trogocytic acquisition of these molecules from conventional dendritic cells (cDCs). Complement component 3 (C3) binds to murine and human MHC II on cDCs. MZ B cells recognize C3 with complement receptor 2 (CR2) and trogocytose the MHC II-C3 complexes, which become exposed on their cell surface. The ubiquitin ligase MARCH1 limits the number of MHC II-C3 complexes displayed on cDCs to prevent their elimination through excessive trogocytosis. Capture of C3 by MHC II thus enables the transfer of cDC-like properties to MZ B cells.


Assuntos
Linfócitos B/imunologia , Complemento C3/metabolismo , Células Dendríticas/imunologia , Tecido Linfoide/imunologia , Adulto , Animais , Apresentação do Antígeno , Linfócitos B/metabolismo , Membrana Celular/metabolismo , Ativação do Complemento , Complemento C3/imunologia , Células Dendríticas/metabolismo , Feminino , Antígenos HLA-D/imunologia , Antígenos HLA-D/metabolismo , Antígenos de Histocompatibilidade Classe II/metabolismo , Humanos , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C3H , Camundongos Endogâmicos C57BL , Pessoa de Meia-Idade , Receptores de Complemento 3d/imunologia , Receptores de Complemento 3d/metabolismo , Linfócitos T/imunologia , Ubiquitina-Proteína Ligases/genética , Ubiquitina-Proteína Ligases/metabolismo , Ubiquitinação
18.
J Neuroimmunol ; 363: 577793, 2022 02 15.
Artigo em Inglês | MEDLINE | ID: mdl-34990981

RESUMO

Immune system dysregulation may be involved in schizophrenia, but biomarker studies have thus far reported inconsistent findings. The relationship of plasma levels of complement markers C3 and C4, with schizophrenia, sociodemographic and clinico-psychological factors were here studied in 183 patients and 212 controls. C3 and C4 levels were significantly higher in the patients and in subjects with elevated C-reactive protein (CRP), and positively correlated with body mass index (BMI) (p < 0.05). Schizophrenia, BMI, and CRP were significant predictors for C3 and C4 levels in multivariate analyses (p < 0.001). In conclusion, complements C3 and C4 are potential peripheral biomarkers in schizophrenia.


Assuntos
Biomarcadores/sangue , Proteína C-Reativa/metabolismo , Complemento C3/metabolismo , Complemento C4/metabolismo , Esquizofrenia/sangue , Adulto , Índice de Massa Corporal , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Esquizofrenia/imunologia
19.
Thromb Haemost ; 122(2): 240-256, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-35062036

RESUMO

BACKGROUND: Endothelial and complement activation were both associated with immunothrombosis, a key determinant of COVID-19 severity, but their interrelation has not yet been investigated. OBJECTIVES: We aimed to determine von Willebrand factor (VWF) antigen (VWF:Ag) concentration, VWF collagen binding activity (VWF:CBA), a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13 (ADAMTS13) activity (ADAMTS13:Ac), and their ratios in hospitalized COVID-19 patients, and to investigate how these parameters and their constellation with complement activation relate to disease severity and in-hospital mortality in COVID-19. METHODS: Samples of 102 hospitalized patients with polymerase chain reaction-confirmed severe acute respiratory syndrome coronavirus 2 positivity were included in our observational cohort study. Patients were stratified according to the peak severity of COVID-19 disease in agreement with the World Health Organization ordinal scale. Twenty-six convalescent plasma donors with previous COVID-19 disease formed the control group. VWF:Ag concentration and VWF:CBA were determined by enzyme-linked immunosorbent assay (ELISA); ADAMTS13:Ac was determined by fluorescence resonance energy transfer. Complement C3 and C3a were measured by turbidimetry and ELISA, respectively. Clinical covariates and markers of inflammation were extracted from hospital records. RESULTS: VWF:Ag and VWF:CBA were elevated in all groups of hospitalized COVID-19 patients and increased in parallel with disease severity. ADAMTS13:Ac was decreased in patients with severe COVID-19, with the lowest values in nonsurvivors. High (> 300%) VWF:Ag concentrations or decreased (< 67%) ADAMTS13:Ac were associated with higher risk of severe COVID-19 disease or in-hospital mortality. The concomitant presence of decreased ADAMTS13:Ac and increased C3a/C3 ratio-indicating complement overactivation and consumption-was a strong independent predictor of in-hospital mortality. CONCLUSION: Our results suggest that an interaction between the VWF-ADAMTS13 axis and complement overactivation and consumption plays an important role in the pathogenesis of COVID-19.


Assuntos
Proteína ADAMTS13/metabolismo , COVID-19/imunologia , Complemento C3/metabolismo , SARS-CoV-2/fisiologia , Fator de von Willebrand/metabolismo , Adulto , Idoso , COVID-19/epidemiologia , COVID-19/mortalidade , Ativação do Complemento , Convalescença , Feminino , Hospitalização , Humanos , Hungria/epidemiologia , Masculino , Pessoa de Meia-Idade , Nefelometria e Turbidimetria , Índice de Gravidade de Doença , Análise de Sobrevida
20.
Clin Immunol ; 235: 108785, 2022 02.
Artigo em Inglês | MEDLINE | ID: mdl-34147650

RESUMO

The FDA approval of pegcetacoplan (Empaveli), a PEGylated compstatin-based C3 therapeutic, as a new treatment for paroxysmal nocturnal hemoglobinuria (PNH) marks a milestone in the history of complement drug discovery. Almost 15 years after the approval of the first complement-specific drug for PNH, the anti-C5 antibody eculizumab, a novel class of complement inhibitors with a distinct mechanism of action finally enters the clinic. This landmark decision broadens the spectrum of available complement therapeutics, offering patients with unmet clinical needs or insufficient responses to anti-C5 therapy an alternative treatment option with a broad activity profile. Here we present a brief historical account of this newly approved complement drug, consolidating its approval within the long research record of the compstatin family of peptidic C3 inhibitors.


Assuntos
Complemento C3/antagonistas & inibidores , Hemoglobinúria Paroxística/tratamento farmacológico , Peptídeos Cíclicos/farmacologia , Complemento C3/metabolismo , Aprovação de Drogas , Regulação da Expressão Gênica/efeitos dos fármacos , Humanos , Peptídeos Cíclicos/química
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