RESUMO
BACKGROUND: SARS-CoV-2 infection is considered as a relapsing inflammatory process with a dysregulation of IL-6 signalling. Classic IL-6 signalling is thought to represent a defence mechanism against pathogens. In contrast, IL-6 trans-signalling has pro-inflammatory effects. In severe COVID-19, therapeutic strategies have focused on global inhibition of IL-6, with controversial results. We hypothesized that specific blockade of IL-6 trans-signalling could inhibit inflammatory response preserving the host defence activity inherent to IL-6 classic signalling. METHODS: To test the role of the specific IL-6 trans-signalling inhibition by sgp130Fc in short- and long-term consequences of COVID-19, we used the established K18-hACE2 transgenic mouse model. Histological as well as immunohistochemical analysis, and pro-inflammatory marker profiling were performed. To investigate IL-6 trans-signalling in human cells we used primary lung microvascular endothelial cells and fibroblasts in the presence/absence of sgp130Fc. FINDINGS: We report that targeting IL-6 trans-signalling by sgp130Fc attenuated SARS-CoV-2-related clinical symptoms and mortality. In surviving mice, the treatment caused a significant decrease in lung damage. In vitro, IL-6 trans-signalling induced strong and persisting JAK1/STAT3 activation in endothelial cells and lung fibroblasts with proinflammatory effects, which were attenuated by sgp130Fc. Our data also suggest that in those cells with scant amounts of IL-6R, the induction of gp130 and IL-6 by IL-6:sIL-6R complex sustains IL-6 trans-signalling. INTERPRETATION: IL-6 trans-signalling fosters progression of COVID-19, and suggests that specific blockade of this signalling mode could offer a promising alternative to mitigate both short- and long-term consequences without affecting the beneficial effects of IL-6 classic signalling. These results have implications for the development of new therapies of lung injury and endotheliopathy in COVID-19. FUNDING: The project was supported by ISCIII, Spain (COV-20/00792 to MB, PI23/01351 to MARH) and the European Commission-Next generation EU (European Union) (Regulation EU 2020/2094), through CSIC's Global Health Platform (PTI Salud Global, SGL2103029 to MB). PID2019-110587RB-I00 (MB) supported by MICIN/AEI/10.13039/501100011033/and PID2022-143034OB-I00 (MB) by MICIN/AEI/10.13039/501100011033/FEDER. MAR-H acknowledges support from ISCIII, Spain and the European Commission-Next generation EU (European Union), through CSIC's Global Health PTI.
Assuntos
COVID-19 , Receptor gp130 de Citocina , Interleucina-6 , Camundongos Transgênicos , SARS-CoV-2 , Transdução de Sinais , Animais , Humanos , Camundongos , Enzima de Conversão de Angiotensina 2/metabolismo , Betacoronavirus , Infecções por Coronavirus/tratamento farmacológico , Infecções por Coronavirus/virologia , Infecções por Coronavirus/patologia , COVID-19/metabolismo , Tratamento Farmacológico da COVID-19 , Receptor gp130 de Citocina/metabolismo , Receptor gp130 de Citocina/antagonistas & inibidores , Modelos Animais de Doenças , Células Endoteliais/metabolismo , Interleucina-6/metabolismo , Pulmão/patologia , Pulmão/virologia , Pulmão/metabolismo , Pneumonia Viral/tratamento farmacológico , Pneumonia Viral/virologia , Pneumonia Viral/patologia , Pneumonia Viral/metabolismo , Receptores de Interleucina-6/metabolismo , Receptores de Interleucina-6/antagonistas & inibidores , Proteínas Recombinantes de Fusão/farmacologia , Índice de Gravidade de Doença , Transdução de Sinais/efeitos dos fármacosRESUMO
IL-6 is one of the major mediators of the hyper-inflammatory responses with complex biological functions as it can signal via different modes of action. IL-6 by classical signalling has anti-inflammatory and antibacterial activities, while trans-signalling mediates pro-inflammatory effects. The net biological effect of IL-6 is established by multiple factors beyond its absolute concentration. Here, we assess the relationship between IL-6 signalling variables [IL-6, soluble IL-6R (sIL-6R) and soluble gp130 (sgp130)] and outcomes in a cohort of 366 COVID-19 patients. The potential trans-signalling was evaluated by a ratio between the pro-inflammatory binary IL-6:sIL-6R complex and the inactive ternary IL-6:sIL-6R:sgp130 complex (binary/ternary complex) and the fold molar excess of sgp130 over sIL-6R (FME). Our data provide new evidence that high levels of IL-6, sIL-6R, sgp130, binary/ternary complex ratio, and low FME are independent predictors of COVID-19 severity in survivor patients (without death), and the combination of IL-6 + sIL-6R + sgp130 exhibited the most robust classification capacity. Conversely, in a subgroup of patients with a very poor prognosis, we found that high levels of IL-6 and low levels of sIL-6R, sgp130, and binary/ternary complex ratio were predictors of death. In this context, the highest predictive capacity corresponded to the combined analysis of IL-6 + FME + lymphopenia + creatinine. Herein, we present IL-6 signalling variables as a helpful tool for the early identification and stratification of patients with clear implications for treatment and clinical decision-making.
Assuntos
COVID-19 , Interleucina-6 , Receptores de Interleucina-6 , Transdução de Sinais , COVID-19/diagnóstico , COVID-19/imunologia , Receptor gp130 de Citocina/metabolismo , Humanos , Interleucina-6/metabolismo , Receptores de Interleucina-6/metabolismo , Índice de Gravidade de DoençaRESUMO
Electrons feed into the mitochondrial electron transport chain (mETC) from NAD- or FAD-dependent enzymes. A shift from glucose to fatty acids increases electron flux through FAD, which can saturate the oxidation capacity of the dedicated coenzyme Q (CoQ) pool and result in the generation of reactive oxygen species. To prevent this, the mETC superstructure can be reconfigured through the degradation of respiratory complex I, liberating associated complex III to increase electron flux via FAD at the expense of NAD. Here, we demonstrate that this adaptation is driven by the ratio of reduced to oxidized CoQ. Saturation of CoQ oxidation capacity induces reverse electron transport from reduced CoQ to complex I, and the resulting local generation of superoxide oxidizes specific complex I proteins, triggering their degradation and the disintegration of the complex. Thus, CoQ redox status acts as a metabolic sensor that fine-tunes mETC configuration in order to match the prevailing substrate profile.
Assuntos
Complexo de Proteínas da Cadeia de Transporte de Elétrons/metabolismo , Transporte de Elétrons , Ubiquinona/metabolismo , Animais , Linhagem Celular , Flavina-Adenina Dinucleotídeo/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , NAD/metabolismo , Espécies Reativas de Oxigênio/metabolismoRESUMO
Coenzyme Q10 deficiency is a clinically and genetically heterogeneous disorder, with manifestations that may range from fatal neonatal multisystem failure, to adult-onset encephalopathy. We report a patient who presented at birth with severe lactic acidosis, proteinuria, dicarboxylic aciduria, and hepatic insufficiency. She also had dilation of left ventricle on echocardiography. Her neurological condition rapidly worsened and despite aggressive care she died at 23 h of life. Muscle histology displayed lipid accumulation. Electron microscopy showed markedly swollen mitochondria with fragmented cristae. Respiratory-chain enzymatic assays showed a reduction of combined activities of complex I+III and II+III with normal activities of isolated complexes. The defect was confirmed in fibroblasts, where it could be rescued by supplementing the culture medium with 10 µM coenzyme Q10. Coenzyme Q10 levels were reduced (28% of controls) in these cells. We performed exome sequencing and focused the analysis on genes involved in coenzyme Q10 biosynthesis. The patient harbored a homozygous c.545T>G, p.(Met182Arg) alteration in COQ2, which was validated by functional complementation in yeast. In this case the biochemical and morphological features were essential to direct the genetic diagnosis. The parents had another pregnancy after the biochemical diagnosis was established, but before the identification of the genetic defect. Because of the potentially high recurrence risk, and given the importance of early CoQ10 supplementation, we decided to treat with CoQ10 the newborn child pending the results of the biochemical assays. Clinicians should consider a similar management in siblings of patients with CoQ10 deficiency without a genetic diagnosis.
Assuntos
Alquil e Aril Transferases/genética , Ataxia/diagnóstico , Ataxia/genética , Mitocôndrias Musculares/genética , Doenças Mitocondriais/diagnóstico , Doenças Mitocondriais/genética , Debilidade Muscular/diagnóstico , Debilidade Muscular/genética , Mutação Puntual , Ubiquinona/análogos & derivados , Ubiquinona/deficiência , Acidose Láctica/sangue , Acidose Láctica/genética , Acidose Láctica/patologia , Alquil e Aril Transferases/deficiência , Ataxia/sangue , Ataxia/patologia , Consanguinidade , Evolução Fatal , Feminino , Expressão Gênica , Insuficiência Hepática/sangue , Insuficiência Hepática/genética , Insuficiência Hepática/patologia , Humanos , Recém-Nascido , Deficiência Intelectual/sangue , Deficiência Intelectual/genética , Deficiência Intelectual/patologia , Mitocôndrias Musculares/enzimologia , Mitocôndrias Musculares/patologia , Doenças Mitocondriais/sangue , Doenças Mitocondriais/patologia , Debilidade Muscular/sangue , Debilidade Muscular/patologia , Músculo Esquelético/enzimologia , Músculo Esquelético/patologia , Proteinúria/sangue , Proteinúria/genética , Proteinúria/patologia , Aminoacidúrias Renais/sangue , Aminoacidúrias Renais/genética , Aminoacidúrias Renais/patologia , Análise de Sequência de DNA , Ubiquinona/sangue , Ubiquinona/genéticaRESUMO
BACKGROUND: COQ4 encodes a protein that organises the multienzyme complex for the synthesis of coenzyme Q(10) (CoQ(10)). A 3.9 Mb deletion of chromosome 9q34.13 was identified in a 3-year-old boy with mental retardation, encephalomyopathy and dysmorphic features. Because the deletion encompassed COQ4, the patient was screened for CoQ(10) deficiency. METHODS: A complete molecular and biochemical characterisation of the patient's fibroblasts and of a yeast model were performed. RESULTS: The study found reduced COQ4 expression (48% of controls), CoQ(10) content and biosynthetic rate (44% and 43% of controls), and activities of respiratory chain complex II+III. Cells displayed a growth defect that was corrected by the addition of CoQ(10) to the culture medium. Knockdown of COQ4 in HeLa cells also resulted in a reduction of CoQ(10.) Diploid yeast haploinsufficient for COQ4 displayed similar CoQ deficiency. Haploinsufficency of other genes involved in CoQ(10) biosynthesis does not cause CoQ deficiency, underscoring the critical role of COQ4. Oral CoQ(10) supplementation resulted in a significant improvement of neuromuscular symptoms, which reappeared after supplementation was temporarily discontinued. CONCLUSION: Mutations of COQ4 should be searched for in patients with CoQ(10) deficiency and encephalomyopathy; patients with genomic rearrangements involving COQ4 should be screened for CoQ(10) deficiency, as they could benefit from supplementation.