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1.
EMBO J ; 41(2): e108690, 2022 12 17.
Artigo em Inglês | MEDLINE | ID: mdl-34931711

RESUMO

During apoptosis, the BCL-2-family protein tBID promotes mitochondrial permeabilization by activating BAX and BAK and by blocking anti-apoptotic BCL-2 members. Here, we report that tBID can also mediate mitochondrial permeabilization by itself, resulting in release of cytochrome c and mitochondrial DNA, caspase activation and apoptosis even in absence of BAX and BAK. This previously unrecognized activity of tBID depends on helix 6, homologous to the pore-forming regions of BAX and BAK, and can be blocked by pro-survival BCL-2 proteins. Importantly, tBID-mediated mitochondrial permeabilization independent of BAX and BAK is physiologically relevant for SMAC release in the immune response against Shigella infection. Furthermore, it can be exploited to kill leukaemia cells with acquired venetoclax resistance due to lack of active BAX and BAK. Our findings define tBID as an effector of mitochondrial permeabilization in apoptosis and provide a new paradigm for BCL-2 proteins, with implications for anti-bacterial immunity and cancer therapy.


Assuntos
Apoptose , Proteína Agonista de Morte Celular de Domínio Interatuante com BH3/metabolismo , Proteínas Reguladoras de Apoptose/metabolismo , Proteína Agonista de Morte Celular de Domínio Interatuante com BH3/química , Proteína Agonista de Morte Celular de Domínio Interatuante com BH3/genética , Células HCT116 , Células HeLa , Humanos , Mitocôndrias/metabolismo , Proteínas Mitocondriais/metabolismo , Domínios Proteicos , Proteólise , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Proteína Killer-Antagonista Homóloga a bcl-2/metabolismo , Proteína X Associada a bcl-2/metabolismo
2.
Nature ; 575(7784): 683-687, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31748744

RESUMO

Caspase-8 is the initiator caspase of extrinsic apoptosis1,2 and inhibits necroptosis mediated by RIPK3 and MLKL. Accordingly, caspase-8 deficiency in mice causes embryonic lethality3, which can be rescued by deletion of either Ripk3 or Mlkl4-6. Here we show that the expression of enzymatically inactive CASP8(C362S) causes embryonic lethality in mice by inducing necroptosis and pyroptosis. Similar to Casp8-/- mice3,7, Casp8C362S/C362S mouse embryos died after endothelial cell necroptosis leading to cardiovascular defects. MLKL deficiency rescued the cardiovascular phenotype but unexpectedly caused perinatal lethality in Casp8C362S/C362S mice, indicating that CASP8(C362S) causes necroptosis-independent death at later stages of embryonic development. Specific loss of the catalytic activity of caspase-8 in intestinal epithelial cells induced intestinal inflammation similar to intestinal epithelial cell-specific Casp8 knockout mice8. Inhibition of necroptosis by additional deletion of Mlkl severely aggravated intestinal inflammation and caused premature lethality in Mlkl knockout mice with specific loss of caspase-8 catalytic activity in intestinal epithelial cells. Expression of CASP8(C362S) triggered the formation of ASC specks, activation of caspase-1 and secretion of IL-1ß. Both embryonic lethality and premature death were completely rescued in Casp8C362S/C362SMlkl-/-Asc-/- or Casp8C362S/C362SMlkl-/-Casp1-/- mice, indicating that the activation of the inflammasome promotes CASP8(C362S)-mediated tissue pathology when necroptosis is blocked. Therefore, caspase-8 represents the molecular switch that controls apoptosis, necroptosis and pyroptosis, and prevents tissue damage during embryonic development and adulthood.


Assuntos
Apoptose/genética , Caspase 8/genética , Caspase 8/metabolismo , Necroptose/genética , Piroptose/genética , Animais , Linhagem Celular , Células Cultivadas , Ativação Enzimática/genética , Perfilação da Expressão Gênica , Técnicas de Inativação de Genes , Células HEK293 , Humanos , Inflamassomos/metabolismo , Mucosa Intestinal/citologia , Mucosa Intestinal/enzimologia , Queratinócitos/citologia , Queratinócitos/patologia , Camundongos , Mutação , Receptor TIE-2/genética , Receptor TIE-2/metabolismo
3.
J Pediatr ; 257: 113392, 2023 06.
Artigo em Inglês | MEDLINE | ID: mdl-36948386

RESUMO

OBJECTIVE: To determine the clinical manifestations, management, and outcomes of pediatric granuloma annulare (GA). STUDY DESIGN: We searched MEDLINE via PubMed, Latin American and Caribbean Health Sciences, and EMBASE from inception to January 2021. We included all original reports of patients <18 years of age with a diagnosis of GA and all original reports describing any intervention, including topical or systemic agents, in these patients. Two authors independently extracted sociodemographics and clinical data of the study patients and treatment(s) used. RESULTS: Of 2440 reports screened, 202 were included (836 patients). The mean age was 5.7 (SD 3.8) years and F:M ratio 1.3:1. Localized GA (n = 384/821, 46.8%) and subcutaneous GA (n = 353/821, 43.0%) were the most prevalent subtypes. The most affected site was lower limbs (n = 272/568, 47.9%). Suspected triggering factors were mainly local trauma. Diabetes was associated in 22 (2.6%) patients. The rate of spontaneous remission was high (n = 140/155, 90.3%), with a median time of 12 months. The most frequent therapies were surgery and topical corticosteroids. Recurrence was observed in 38.3% (n = 168/439) of patients, regardless of treatment. CONCLUSIONS: Pediatric GA frequently resolves spontaneously yet displays a high recurrence rate. Hence, in asymptomatic forms, invasive therapies are not recommended as first-line treatment.


Assuntos
Diabetes Mellitus , Granuloma Anular , Humanos , Criança , Pré-Escolar , Granuloma Anular/terapia , Granuloma Anular/tratamento farmacológico , Glucocorticoides/uso terapêutico , Remissão Espontânea , Diagnóstico Diferencial
4.
EMBO J ; 35(10): 1058-76, 2016 05 17.
Artigo em Inglês | MEDLINE | ID: mdl-26988032

RESUMO

Amino acids regulate TOR complex 1 (TORC1) via two counteracting mechanisms, one activating and one inactivating. The presence of amino acids causes TORC1 recruitment to lysosomes where TORC1 is activated by binding Rheb. How the absence of amino acids inactivates TORC1 is less well understood. Amino acid starvation recruits the TSC1/TSC2 complex to the vicinity of TORC1 to inhibit Rheb; however, the upstream mechanisms regulating TSC2 are not known. We identify here the eIF4A-containing eIF4F translation initiation complex as an upstream regulator of TSC2 in response to amino acid withdrawal in Drosophila We find that TORC1 and translation preinitiation complexes bind each other. Cells lacking eIF4F components retain elevated TORC1 activity upon amino acid removal. This effect is specific for eIF4F and not a general consequence of blocked translation. This study identifies specific components of the translation machinery as important mediators of TORC1 inactivation upon amino acid removal.


Assuntos
Proteínas de Drosophila/metabolismo , Fator de Iniciação 4A em Eucariotos/metabolismo , Fatores de Transcrição/metabolismo , Sistemas de Transporte de Aminoácidos Neutros/genética , Sistemas de Transporte de Aminoácidos Neutros/metabolismo , Aminoácidos/metabolismo , Animais , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Linhagem Celular , Drosophila , Proteínas de Drosophila/genética , Fator de Iniciação 4A em Eucariotos/genética , Células HeLa , Humanos
5.
Brain ; 142(6): 1736-1750, 2019 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-31038156

RESUMO

Tauopathies are neurodegenerative diseases characterized by the intraneuronal accumulation of aggregated tau. The staging of this neurodegenerative process is well established for Alzheimer's disease as well as for other tauopathies. The stereotypical pattern of tau pathology in these diseases is consistent with the hypothesis that the tau protein can spread in a 'prion-like' manner. It proposes that extracellular pathological tau species can transmit pathology from cell to cell. Accordingly, by targeting these spreading species with therapeutic antibodies one should be able to slow or halt the progression of tau pathology. To be effective, antibodies should neutralize the pathological species present in Alzheimer's disease brains and block their cell-to-cell spread. To evaluate both aspects, tau antibody D, which recognizes an epitope in the central region of tau, and was selected for its outstanding ability to block tau seeding in cell based assays, was used in this study. Here, we addressed two fundamental questions: (i) can this anti-tau antibody neutralize the pathological species present in Alzheimer's disease brains; and (ii) can it block the cell-to-cell spread of tau seeds in vivo? First, antibody D effectively prevented the induction of tau pathology in the brains of transgenic mice that had been injected with human Alzheimer's disease brain extracts, showing that it could effectively neutralize the pathological species present in these extracts. Second, by using K18 P301L tau fibrils to induce pathology, we further demonstrated that antibody D was also capable of blocking the progression of tau pathology to distal brain regions. In contrast, an amino-terminal tau antibody, which was less effective at blocking tau seeding in vitro showed less efficacy in reducing Alzheimer's disease patient tau driven pathology in the transgenic mouse model. We did not address whether the same is true for a spectrum of other amino-terminal antibodies that were tested in vitro. These data highlight important differences between tau antibodies and, when taken together with other recently published data, suggest that epitope may be important for function.


Assuntos
Doença de Alzheimer/patologia , Emaranhados Neurofibrilares/patologia , Tauopatias/metabolismo , Proteínas tau/genética , Doença de Alzheimer/metabolismo , Doença de Alzheimer/terapia , Animais , Anticorpos/metabolismo , Encéfalo/metabolismo , Encéfalo/patologia , Modelos Animais de Doenças , Progressão da Doença , Epitopos , Feminino , Fatores Imunológicos/metabolismo , Imunoterapia , Masculino , Camundongos Transgênicos , Proteínas tau/metabolismo
6.
Toxicol Appl Pharmacol ; 352: 59-67, 2018 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-29782965

RESUMO

Saponins exhibit several biological and pharmacological activities, such as antibacterial, anti-inflammatory and anticancer effects. Many studies attribute their activities to their interactions with cholesterol. In this study, we focus on the steroid saponin ginsenoside Rh2, one of the active principles of Panax ginseng root. Some evidence suggests that lipid rafts, defined as nanodomains enriched in cholesterol and sphingolipids, could be involved in the Rh2-induced apoptosis. However, the role of membrane lipids, especially cholesterol, in this process is still poorly understood. Here, we demonstrate that (i) A549, THP-1 and U937 cells are all susceptible to the Rh2-induced apoptosis but to a differential extent and (ii) the cytotoxic effect inversely correlates with the cell membrane cholesterol content. Upon cholesterol depletion via methyl-ß-cyclodextrin, those three cells lines become more sensitive to Rh2-induced apoptosis. Then, focusing on the cholesterol-auxotroph U937 cell line, we showed that Rh2 alters plasma membrane fluidity by compacting the hydrophobic core of lipid bilayer (DPH anisotropy) and relaxing the interfacial packaging of the polar head of phospholipids (TMA-DPH anisotropy). The treatment with Rh2 conducts to the dephosphorylation of Akt and the activation of the intrinsic pathway of apoptosis (loss of mitochondrial membrane potential, caspase-9 and -3 activation). All these features are induced faster in cholesterol-depleted cells, which could be explained by faster cell accumulation of Rh2 in these conditions. This work is the first reporting that membrane cholesterol could delay the activity of ginsenoside Rh2, renewing the idea that saponin cytotoxicity is ascribed to an interaction with membrane cholesterol.


Assuntos
Antineoplásicos Fitogênicos/farmacologia , Apoptose/efeitos dos fármacos , Colesterol/metabolismo , Ginsenosídeos/farmacologia , Microdomínios da Membrana/efeitos dos fármacos , Células A549 , Caspase 3/metabolismo , Caspase 9/metabolismo , Colesterol/deficiência , Humanos , Fluidez de Membrana/efeitos dos fármacos , Microdomínios da Membrana/metabolismo , Microdomínios da Membrana/patologia , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Mitocôndrias/patologia , Fosforilação , Proteínas Proto-Oncogênicas c-akt/metabolismo , Transdução de Sinais/efeitos dos fármacos , Células THP-1 , Células U937
7.
Anesthesiology ; 120(2): 326-34, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24317204

RESUMO

BACKGROUND: The authors sought to determine the level of inspiratory pressure minimizing the risk of gastric insufflation while providing adequate pulmonary ventilation. The primary endpoint was the increase in incidence of gastric insufflation detected by ultrasonography of the antrum while inspiratory pressure for facemask pressure-controlled ventilation increased from 10 to 25 cm H2O. METHODS: In this prospective, randomized, double-blind study, patients were allocated to one of the four groups (P10, P15, P20, and P25) defined by the inspiratory pressure applied during controlled-pressure ventilation: 10, 15, 20, and 25 cm H2O. Anesthesia was induced using propofol and remifentanil; no neuromuscular-blocking agent was administered. Once loss of eyelash reflex occurred, facemask ventilation was started for a 2-min period while gastric insufflation was detected by auscultation and by real-time ultrasonography of the antrum. The cross-sectional antral area was measured using ultrasonography before and after facemask ventilation. Respiratory parameters were recorded. RESULTS: Sixty-seven patients were analyzed. The authors registered statistically significant increases in incidences of gastric insufflation with inspiratory pressure, from 0% (group P10) to 41% (group P25) according to auscultation, and from 19 to 59% according to ultrasonography. In groups P20 and P25, detection of gastric insufflation by ultrasonography was associated with a statistically significant increase in the antral area. Lung ventilation was insufficient for group P10. CONCLUSION: Inspiratory pressure of 15 cm H2O allowed for reduced occurrence of gastric insufflation with proper lung ventilation during induction of anesthesia with remifentanil and propofol in nonparalyzed and nonobese patients. (Anesthesiology 2014; 120:326-34).


Assuntos
Auscultação/métodos , Insuflação , Complicações Intraoperatórias/diagnóstico por imagem , Complicações Intraoperatórias/prevenção & controle , Máscaras Laríngeas , Respiração Artificial/efeitos adversos , Estômago/diagnóstico por imagem , Adulto , Idoso , Manuseio das Vias Aéreas , Algoritmos , Anatomia Transversal , Anestesia Intravenosa , Cromatografia Gasosa , Sistemas Computacionais , Método Duplo-Cego , Determinação de Ponto Final , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Probabilidade , Estudos Prospectivos , Antro Pilórico/diagnóstico por imagem , Respiração Artificial/métodos , Ultrassonografia
8.
Cell Death Differ ; 31(5): 544-557, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38514848

RESUMO

The dysregulated immune response and inflammation resulting in severe COVID-19 are still incompletely understood. Having recently determined that aberrant death-ligand-induced cell death can cause lethal inflammation, we hypothesized that this process might also cause or contribute to inflammatory disease and lung failure following SARS-CoV-2 infection. To test this hypothesis, we developed a novel mouse-adapted SARS-CoV-2 model (MA20) that recapitulates key pathological features of COVID-19. Concomitantly with occurrence of cell death and inflammation, FasL expression was significantly increased on inflammatory monocytic macrophages and NK cells in the lungs of MA20-infected mice. Importantly, therapeutic FasL inhibition markedly increased survival of both, young and old MA20-infected mice coincident with substantially reduced cell death and inflammation in their lungs. Intriguingly, FasL was also increased in the bronchoalveolar lavage fluid of critically-ill COVID-19 patients. Together, these results identify FasL as a crucial host factor driving the immuno-pathology that underlies COVID-19 severity and lethality, and imply that patients with severe COVID-19 may significantly benefit from therapeutic inhibition of FasL.


Assuntos
COVID-19 , Modelos Animais de Doenças , Proteína Ligante Fas , SARS-CoV-2 , COVID-19/patologia , COVID-19/imunologia , COVID-19/metabolismo , COVID-19/virologia , COVID-19/mortalidade , Animais , Proteína Ligante Fas/metabolismo , Camundongos , Humanos , Pulmão/patologia , Pulmão/virologia , Pulmão/metabolismo , Células Matadoras Naturais/imunologia , Células Matadoras Naturais/metabolismo , Camundongos Endogâmicos C57BL , Feminino , Masculino , Inflamação/patologia , Inflamação/metabolismo , Líquido da Lavagem Broncoalveolar , Macrófagos/metabolismo , Macrófagos/patologia
9.
RSC Med Chem ; 14(2): 378-385, 2023 Feb 22.
Artigo em Inglês | MEDLINE | ID: mdl-36846375

RESUMO

Transglutaminase 2 (TG2), also referred to as tissue transglutaminase, plays crucial roles in both protein crosslinking and cell signalling. It is capable of both catalysing transamidation and acting as a G-protein, these activities being conformation-dependent, mutually exclusive, and tightly regulated. The dysregulation of both activities has been implicated in numerous pathologies. TG2 is expressed ubiquitously in humans and is localized both intracellularly and extracellularly. Targeted TG2 therapies have been developed but have faced numerous hurdles including decreased efficacy in vivo. Our latest efforts in inhibitor optimization involve the modification of a previous lead compound's scaffold by insertion of various amino acid residues into the peptidomimetic backbone, and derivatization of the N-terminus with substituted phenylacetic acids, resulting in 28 novel irreversible inhibitors. These inhibitors were evaluated for their ability to inhibit TG2 in vitro and their pharmacokinetic properties, and the most promising candidate 35 (k inact/K I = 760 × 103 M-1 min-1) was tested in a cancer stem cell model. Although these inhibitors display exceptional potency versus TG2, with k inact/K I ratios nearly ten-fold higher than their parent compound, their pharmacokinetic properties and cellular activity limit their therapeutic potential. However, they do serve as a scaffold for the development of potent research tools.

10.
Sci Adv ; 9(30): eadg2829, 2023 07 28.
Artigo em Inglês | MEDLINE | ID: mdl-37494451

RESUMO

Cell death coordinates repair programs following pathogen attack and tissue injury. However, aberrant cell death can interfere with such programs and cause organ failure. Cellular FLICE-like inhibitory protein (cFLIP) is a crucial regulator of cell death and a substrate of Caspase-8. However, the physiological role of cFLIP cleavage by Caspase-8 remains elusive. Here, we found an essential role for cFLIP cleavage in restraining cell death in different pathophysiological scenarios. Mice expressing a cleavage-resistant cFLIP mutant, CflipD377A, exhibited increased sensitivity to severe acute respiratory syndrome coronavirus (SARS-CoV)-induced lethality, impaired skin wound healing, and increased tissue damage caused by Sharpin deficiency. In vitro, abrogation of cFLIP cleavage sensitizes cells to tumor necrosis factor(TNF)-induced necroptosis and apoptosis by favoring complex-II formation. Mechanistically, the cell death-sensitizing effect of the D377A mutation depends on glutamine-469. These results reveal a crucial role for cFLIP cleavage in controlling the amplitude of cell death responses occurring upon tissue stress to ensure the execution of repair programs.


Assuntos
Apoptose , Viroses , Animais , Camundongos , Caspase 8/genética , Pele/metabolismo , Fator de Necrose Tumoral alfa/metabolismo
11.
Front Med (Lausanne) ; 10: 1129288, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37168268

RESUMO

Background: Symptoms lasting longer than 12 weeks after severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) infection are called post-coronavirus disease (COVID) syndrome (PCS). The identification of new biomarkers that predict the occurrence or course of PCS in terms of a post-viral syndrome is vital. T-cell dysfunction, cytokine imbalance, and impaired autoimmunity have been reported in PCS. Nevertheless, there is still a lack of conclusive information on the underlying mechanisms due to, among other things, a lack of controlled study designs. Methods: Here, we conducted a prospective, controlled study to characterize the humoral and cellular immune response in unvaccinated patients with and without PCS following SARS-CoV-2 infection over 7 months and unexposed donors. Results: Patients with PCS showed as early as 6 weeks and 7 months after symptom onset significantly increased frequencies of SARS-CoV-2-specific CD4+ and CD8+ T-cells secreting IFNγ, TNF, and expressing CD40L, as well as plasmacytoid dendritic cells (pDC) with an activated phenotype. Remarkably, the immunosuppressive counterparts type 1 regulatory T-cells (TR1: CD49b/LAG-3+) and IL-4 were more abundant in PCS+. Conclusion: This work describes immunological alterations between inflammation and immunosuppression in COVID-19 convalescents with and without PCS, which may provide potential directions for future epidemiological investigations and targeted treatments.

12.
Mol Microbiol ; 79(1): 94-108, 2011 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-21166896

RESUMO

Awareness is growing that drug target validation should involve systems analysis of cellular networks. There is less appreciation, though, that the composition of networks may change in response to drugs. If the response is homeostatic (e.g. through upregulation of the target protein), this may neutralize the inhibitory effect. In this scenario the effect on cell growth and survival would be less than anticipated based on affinity of the drug for its target. Glycolysis is the sole free-energy source for the deadly parasite Trypanosoma brucei and is therefore a possible target pathway for anti-trypanosomal drugs. Plasma-membrane glucose transport exerts high control over trypanosome glycolysis and hence the transporter is a promising drug target. Here we show that at high inhibitor concentrations, inhibition of trypanosome glucose transport causes cell death. Most interestingly, sublethal concentrations initiate a domino effect in which network adaptations enhance inhibition. This happens via (i) metabolic control exerted by the target protein, (ii) decreases in mRNAs encoding the target protein and other proteins in the same pathway, and (iii) partial differentiation of the cells leading to (low) expression of immunogenic insect-stage coat proteins. We discuss how these 'anti-homeostatic' responses together may facilitate killing of parasites at an acceptable drug dosage.


Assuntos
Antiprotozoários/farmacologia , Proteínas Facilitadoras de Transporte de Glucose/antagonistas & inibidores , Trypanosoma brucei brucei/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Perfilação da Expressão Gênica , Regulação da Expressão Gênica/efeitos dos fármacos , Redes e Vias Metabólicas , Biologia de Sistemas , Trypanosoma brucei brucei/metabolismo
13.
Cell Death Discov ; 8(1): 477, 2022 Dec 02.
Artigo em Inglês | MEDLINE | ID: mdl-36460631

RESUMO

Cilia are sensory organelles that project from the surface of almost all cells. Nephronophthisis (NPH) and NPH-related ciliopathies are degenerative genetic diseases caused by mutation of cilia-associated genes. These kidney disorders are characterized by progressive loss of functional tubular epithelial cells which is associated with inflammation, progressive fibrosis, and cyst formation, ultimately leading to end-stage renal disease. However, disease mechanisms remain poorly understood. Here, we show that targeted deletion of cilia in renal epithelial cells enhanced susceptibility to necroptotic cell death under inflammatory conditions. Treatment of non-ciliated cells with tumor necrosis factor (TNF) α and the SMAC mimetic birinapant resulted in Ripk1-dependent cell death, while viability of ciliated cells was almost not affected. Cell death could be enhanced and shifted toward necroptosis by the caspase inhibitor emricasan, which could be blocked by inhibitors of Ripk1 and Ripk3. Moreover, combined treatment of ciliated and non-ciliated cells with TNFα and cycloheximide induced a cell death response that could be partially rescued with emricasan in ciliated cells. In contrast, non-ciliated cells responded with pronounced cell death that was blocked by necroptosis inhibitors. Consistently, combined treatment with interferon-γ and emricasan induced cell death only in non-ciliated cells. Mechanistically, enhanced necroptosis induced by loss of cilia could be explained by induction of Ripk3 and increased abundance of autophagy components, including p62 and LC3 associated with the Ripk1/Ripk3 necrosome. Genetic ablation of cilia in renal tubular epithelial cells in mice resulted in TUNEL positivity and increased expression of Ripk3 in kidney tissue. Moreover, loss of Nphp1, the most frequent cause of NPH, further increased susceptibility to necroptosis in non-ciliated epithelial cells, suggesting that necroptosis might contribute to the pathogenesis of the disease. Together, these data provide a link between cilia-related signaling and cell death responses and shed new light on the disease pathogenesis of NPH-related ciliopathies.

14.
EMBO Mol Med ; 14(8): e15888, 2022 08 08.
Artigo em Inglês | MEDLINE | ID: mdl-35785445

RESUMO

Durable cell-mediated immune responses require efficient innate immune signaling and the release of pro-inflammatory cytokines. How precisely mRNA vaccines trigger innate immune cells for shaping antigen specific adaptive immunity remains unknown. Here, we show that SARS-CoV-2 mRNA vaccination primes human monocyte-derived macrophages for activation of the NLRP3 inflammasome. Spike protein exposed macrophages undergo NLRP3-driven pyroptotic cell death and subsequently secrete mature interleukin-1ß. These effects depend on activation of spleen tyrosine kinase (SYK) coupled to C-type lectin receptors. Using autologous cocultures, we show that SYK and NLRP3 orchestrate macrophage-driven activation of effector memory T cells. Furthermore, vaccination-induced macrophage priming can be enhanced with repetitive antigen exposure providing a rationale for prime-boost concepts to augment innate immune signaling in SARS-CoV-2 vaccination. Collectively, these findings identify SYK as a regulatory node capable of differentiating between primed and unprimed macrophages, which modulate spike protein-specific T cell responses.


Assuntos
COVID-19 , Proteína 3 que Contém Domínio de Pirina da Família NLR , COVID-19/prevenção & controle , Vacinas contra COVID-19 , Humanos , Imunidade Inata , Inflamassomos/metabolismo , Interleucina-1beta , Peptídeos e Proteínas de Sinalização Intracelular/genética , Proteínas Tirosina Quinases/metabolismo , RNA Mensageiro/genética , SARS-CoV-2 , Glicoproteína da Espícula de Coronavírus/genética , Quinase Syk , Vacinação
15.
EMBO Mol Med ; 13(8): e14150, 2021 08 09.
Artigo em Inglês | MEDLINE | ID: mdl-34133077

RESUMO

Innate immunity triggers responsible for viral control or hyperinflammation in COVID-19 are largely unknown. Here we show that the SARS-CoV-2 spike protein (S-protein) primes inflammasome formation and release of mature interleukin-1ß (IL-1ß) in macrophages derived from COVID-19 patients but not in macrophages from healthy SARS-CoV-2 naïve individuals. Furthermore, longitudinal analyses reveal robust S-protein-driven inflammasome activation in macrophages isolated from convalescent COVID-19 patients, which correlates with distinct epigenetic and gene expression signatures suggesting innate immune memory after recovery from COVID-19. Importantly, we show that S-protein-driven IL-1ß secretion from patient-derived macrophages requires non-specific monocyte pre-activation in vivo to trigger NLRP3-inflammasome signaling. Our findings reveal that SARS-CoV-2 infection causes profound and long-lived reprogramming of macrophages resulting in augmented immunogenicity of the SARS-CoV-2 S-protein, a major vaccine antigen and potent driver of adaptive and innate immune signaling.


Assuntos
COVID-19 , Glicoproteína da Espícula de Coronavírus , Humanos , Imunidade Inata , Inflamassomos , Interleucina-1beta , Macrófagos , Proteína 3 que Contém Domínio de Pirina da Família NLR/genética , SARS-CoV-2
16.
Cell Death Dis ; 11(9): 740, 2020 09 10.
Artigo em Inglês | MEDLINE | ID: mdl-32913203

RESUMO

The BH3-only protein NOXA is a regulator of mitochondrial apoptosis by specifically antagonizing the anti-apoptotic protein MCL-1. Here we show that the E3 ubiquitin ligase CHIP controls NOXA stability after DNA damage. Our findings reveal that CHIP and MCL-1 are binding partners of NOXA and differentially define the fate of NOXA. Whereas NOXA is initially targeted to mitochondria upon MCL-1-binding, CHIP mediates ubiquitylation of cytosolic NOXA and promotes lysosomal degradation of NOXA, which is not bound by MCL-1. Our data indicate that MCL-1 defines NOXA abundance and its pro-apoptotic activity. Increased NOXA levels beyond this threshold are effectively removed by lysosomal protein degradation triggered via CHIP-mediated ubiquitylation. Together, these results shed new light on regulatory circuits controlling DNA damage response and identified the E3 ligase CHIP as a new molecular guardian, which restricts the cytosolic accumulation of NOXA upon genotoxic stress.


Assuntos
Dano ao DNA/genética , Lisossomos/metabolismo , Ubiquitina-Proteína Ligases/metabolismo , Ubiquitinação/genética , Humanos
17.
PLoS One ; 12(11): e0187217, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-29095858

RESUMO

Krabbe disease is a fatal rare inherited lipid storage disorder affecting 1:100,000 births. This illness is caused by mutations in the galc gene encoding for the enzyme galactosylceramidase (GALC). Dysfunction of GALC has been linked to the toxic build-up of the galactolipid, galactosylsphingosine (psychosine), which induces cell death of oligodendrocytes. Previous studies show that phospholipase A2 (PLA2) may play a role in psychosine induce cell death. Here, we demonstrate that non-selective inhibition of cPLA2/sPLA2 and selective inhibition of cPLA2, but not sPLA2, also attenuates psychosine-induced cell death of human astrocytes. This study shows that extracellular calcium is required for psychosine induced cell death, but intracellular calcium release, reactive oxygen species or release of soluble factors are not involved. These findings suggest a cell autonomous effect, at least in human astrocytes. Supporting a role for PLA2 in psychosine-induced cell death of oligodendrocytes and astrocytes, the results show inhibition of PLA2 attenuates psychosine-induced decrease in the expression of astrocyte marker vimentin as well as myelin basic protein (MBP), myelin oligodendrocyte glycoprotein (MOG) and the neuronal marker SMI-32 in organotypic slice cultures. These findings provide further mechanistic details of psychosine-induced death of glia and suggest a role for PLA2 in the process. This work also supports the proposal that novel drugs for Krabbe disease may require testing on astrocytes as well as oligodendrocytes for more holistic prediction of pre-clinical and clinical efficacy.


Assuntos
Astrócitos/fisiologia , Doenças Desmielinizantes , Neurônios/patologia , Fosfolipases A2/fisiologia , Psicosina/fisiologia , Animais , Células Cultivadas , Inibidores Enzimáticos/farmacologia , Humanos , Camundongos , Fosfolipases A2/efeitos dos fármacos
18.
J Med Chem ; 60(18): 7910-7927, 2017 09 28.
Artigo em Inglês | MEDLINE | ID: mdl-28858494

RESUMO

Human tissue transglutaminase (hTG2) is a multifunctional enzyme. It is primarily known for its calcium-dependent transamidation activity that leads to formation of an isopeptide bond between glutamine and lysine residues found on the surface of proteins, but it is also a GTP binding protein. Overexpression and unregulated hTG2 activity have been associated with numerous human diseases, including cancer stem cell survival and metastatic phenotype. Herein, we present a series of targeted covalent inhibitors (TCIs) based on our previously reported Cbz-Lys scaffold. From this structure-activity relationship (SAR) study, novel irreversible inhibitors were identified that block the transamidation activity of hTG2 and allosterically abolish its GTP binding ability with a high degree of selectivity and efficiency (kinact/KI > 105 M-1 min-1). One optimized inhibitor (VA4) was also shown to inhibit epidermal cancer stem cell invasion with an EC50 of 3.9 µM, representing a significant improvement over our previously reported "hit" NC9.


Assuntos
Desenho de Fármacos , Inibidores Enzimáticos/química , Inibidores Enzimáticos/farmacologia , Proteínas de Ligação ao GTP/antagonistas & inibidores , Guanosina Trifosfato/metabolismo , Transglutaminases/antagonistas & inibidores , Linhagem Celular , Proteínas de Ligação ao GTP/metabolismo , Humanos , Células-Tronco Neoplásicas/citologia , Células-Tronco Neoplásicas/efeitos dos fármacos , Células-Tronco Neoplásicas/metabolismo , Ligação Proteica/efeitos dos fármacos , Proteína 2 Glutamina gama-Glutamiltransferase , Relação Estrutura-Atividade , Transglutaminases/metabolismo
19.
Physiol Behav ; 151: 557-62, 2015 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-26325014

RESUMO

Exercise can suppress appetite and energy intake but the impact of the timing of exercise remains unknown. Knowing that orexigenic hormone levels decrease during exercise but rapidly increase afterward, the aim of the current study was to investigate whether energy intake is increasingly reduced when exercise immediately precedes a meal compared to when a delay occurs between the exercise and the meal. Non-obese boys (15-20 years old; N=12) were individually evaluated while performing two randomly assigned experimental visits: 1) a 30-min exercise session of moderate-to-vigorous intensity followed immediately by an ad libitum buffet at 12 PM and 2), an identical session followed by a 135-min waiting period and an ad libitum buffet-type meal at 12 PM. In both conditions, a snack in the afternoon and a second ad libitum buffet-type meal at 5 PM were served. Findings showed that hunger ratings were similar under both conditions. The exercise session immediately prior to the meal compared with the condition with a >2h delay led to reduction of 11% and 23% in overall and lipid energy intakes at lunch, respectively (P-values>0.05). No significant differences were found in the energy intakes from the afternoon snack and dinner. Apart from lipids at lunch, the proportions of energy from the various macronutrients at each meal were similar. This study reveals that being physically active before a meal plays a role in acute energy intake reduction when a shorter delay is present between exercise and a meal. In addition, the absence of compensation over several hours is noteworthy.


Assuntos
Ingestão de Energia , Exercício Físico , Refeições , Adolescente , Apetite/fisiologia , Ingestão de Energia/fisiologia , Exercício Físico/fisiologia , Humanos , Masculino , Saciação/fisiologia , Fatores de Tempo , Adulto Jovem
20.
Mol Cell Oncol ; 1(1): e29906, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-27308315

RESUMO

Biochemical analyses have characterized the BH3-only protein family member Noxa as a "sensitizer" with weak pro-apoptotic activity. Investigations into cancer cell responses to chemotherapeutic agents have identified Noxa as a pivotal factor mediating the cytotoxic effect of a plethora of anticancer treatments independent of its own pro-apoptotic activity. Accumulating evidence now suggests that tumor cells exert a number of strategies to counteract Noxa function by exploiting diverse cellular regulatory circuits that normally govern Noxa expression during cellular stress responses. Here, we summarize data concerning the role of Noxa in cancer chemosensitivity and highlight the potential of this enigmatic BH3-only protein family member in current and novel anticancer therapies.

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