RESUMO
Ptpn6 is a cytoplasmic phosphatase that functions to prevent autoimmune and interleukin-1 (IL-1) receptor-dependent, caspase-1-independent inflammatory disease. Conditional deletion of Ptpn6 in neutrophils (Ptpn6∆PMN) is sufficient to initiate IL-1 receptor-dependent cutaneous inflammatory disease, but the source of IL-1 and the mechanisms behind IL-1 release remain unclear. Here, we investigate the mechanisms controlling IL-1α/ß release from neutrophils by inhibiting caspase-8-dependent apoptosis and Ripk1-Ripk3-Mlkl-regulated necroptosis. Loss of Ripk1 accelerated disease onset, whereas combined deletion of caspase-8 and either Ripk3 or Mlkl strongly protected Ptpn6∆PMN mice. Ptpn6∆PMN neutrophils displayed increased p38 mitogen-activated protein kinase-dependent Ripk1-independent IL-1 and tumor necrosis factor production, and were prone to cell death. Together, these data emphasize dual functions for Ptpn6 in the negative regulation of p38 mitogen-activated protein kinase activation to control tumor necrosis factor and IL-1α/ß expression, and in maintaining Ripk1 function to prevent caspase-8- and Ripk3-Mlkl-dependent cell death and concomitant IL-1α/ß release.
Assuntos
Apoptose/imunologia , Caspase 8/imunologia , Neutrófilos/imunologia , Proteínas Quinases/imunologia , Proteína Tirosina Fosfatase não Receptora Tipo 6/metabolismo , Proteína Serina-Treonina Quinases de Interação com Receptores/imunologia , Animais , Caspase 8/genética , Células Cultivadas , Deleção de Genes , Inflamação/imunologia , Interleucina-1/imunologia , Interleucina-1alfa/metabolismo , Interleucina-1beta/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Proteína Tirosina Fosfatase não Receptora Tipo 6/genética , Receptores Tipo I de Interleucina-1/imunologia , Fator de Necrose Tumoral alfa/metabolismo , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismoRESUMO
Necroptosis is a regulated form of necrosis, with the dying cell rupturing and releasing intracellular components that can trigger an innate immune response. Toll-like receptor 3 and 4 agonists, tumor necrosis factor, certain viral infections, or the T cell receptor can trigger necroptosis if the activity of the protease caspase-8 is compromised. Necroptosis signaling is modulated by the kinase RIPK1 and requires the kinase RIPK3 and the pseudokinase MLKL. Either RIPK3 deficiency or RIPK1 inhibition confers resistance in various animal disease models, suggesting that inflammation caused by necroptosis contributes to tissue damage and that inhibitors of these kinases could have therapeutic potential. Recent studies have revealed unexpected complexity in the regulation of cell death programs by RIPK1 and RIPK3 with the possibility that necroptosis is but one mechanism by which these kinases promote inflammation.
Assuntos
Regulação da Expressão Gênica , Necrose/genética , Proteínas Quinases/genética , Proteína Serina-Treonina Quinases de Interação com Receptores/genética , Animais , Apoptose , Caspase 8/genética , Caspase 8/imunologia , Perfilação da Expressão Gênica , Humanos , Imunidade Inata , Inflamação , Necrose/imunologia , Necrose/patologia , Proteínas Quinases/imunologia , Proteína Serina-Treonina Quinases de Interação com Receptores/imunologia , Transdução de Sinais , Receptor 3 Toll-Like/genética , Receptor 3 Toll-Like/imunologia , Fator de Necrose Tumoral alfa/genética , Fator de Necrose Tumoral alfa/imunologiaRESUMO
Inflammation is a healthy response to infection or danger and should be rapid, specific and terminated once the threat has passed. Inflammatory diseases, where this regulation fails, cause considerable human suffering. Treatments have successfully targeted pro-inflammatory cytokines, such as tumor-necrosis factor (TNF), that directly induce genes encoding inflammatory products. Inflammatory signals, including TNF, may also directly induce caspase-independent cell death (necroptosis), which can also elicit inflammation. Necroptosis was originally defined as being dependent on the kinase RIPK1 but is now known to be dependent on RIPK3 and the pseudo-kinase MLKL. Therefore, RIPK1, RIPK3 and MLKL are potential therapeutic targets. RIPK1 and RIPK3 also directly regulate inflammatory signaling, which complicates interpretation of their function but might alter their therapeutic utility. This Review examines the role of cell death, particularly necroptosis, in inflammation, in the context of recent insights into the roles of the key necroptosis effector molecules RIPK1, RIPK3 and MLKL.
Assuntos
Inflamação/imunologia , Necrose/imunologia , Proteína Serina-Treonina Quinases de Interação com Receptores/imunologia , Animais , Citocinas/imunologia , Citocinas/metabolismo , Humanos , Inflamação/metabolismo , Modelos Imunológicos , Proteínas Quinases/imunologia , Proteínas Quinases/metabolismo , Proteína Serina-Treonina Quinases de Interação com Receptores/metabolismo , Transdução de Sinais/imunologiaRESUMO
RIPK3 kinase-mediated phosphorylation of MLKL pseudokinase is the execution event of necroptosis. Two independent reports-in Immunity (Yoon et al., 2017) and Cell (Gong et al., 2017)-reveal that MLKL affects homeostatic membrane trafficking and necroptosis-enhanced bubble formation involving interaction with the ESCRT machinery.
Assuntos
Apoptose , Membrana Celular/metabolismo , Vesículas Extracelulares/metabolismo , Necrose , Proteínas Quinases/metabolismo , Transporte Proteico , Proteína Serina-Treonina Quinases de Interação com Receptores/metabolismo , Animais , Complexos Endossomais de Distribuição Requeridos para Transporte , Humanos , Proteínas Quinases/imunologiaRESUMO
Parkinson's disease is a neurodegenerative disorder with motor symptoms linked to the loss of dopaminergic neurons in the substantia nigra compacta. Although the mechanisms that trigger the loss of dopaminergic neurons are unclear, mitochondrial dysfunction and inflammation are thought to have key roles1,2. An early-onset form of Parkinson's disease is associated with mutations in the PINK1 kinase and PRKN ubiquitin ligase genes3. PINK1 and Parkin (encoded by PRKN) are involved in the clearance of damaged mitochondria in cultured cells4, but recent evidence obtained using knockout and knockin mouse models have led to contradictory results regarding the contributions of PINK1 and Parkin to mitophagy in vivo5-8. It has previously been shown that PINK1 and Parkin have a key role in adaptive immunity by repressing presentation of mitochondrial antigens9, which suggests that autoimmune mechanisms participate in the aetiology of Parkinson's disease. Here we show that intestinal infection with Gram-negative bacteria in Pink1-/- mice engages mitochondrial antigen presentation and autoimmune mechanisms that elicit the establishment of cytotoxic mitochondria-specific CD8+ T cells in the periphery and in the brain. Notably, these mice show a sharp decrease in the density of dopaminergic axonal varicosities in the striatum and are affected by motor impairment that is reversed after treatment with L-DOPA. These data support the idea that PINK1 is a repressor of the immune system, and provide a pathophysiological model in which intestinal infection acts as a triggering event in Parkinson's disease, which highlights the relevance of the gut-brain axis in the disease10.
Assuntos
Infecções por Enterobacteriaceae/microbiologia , Infecções por Enterobacteriaceae/fisiopatologia , Intestinos/microbiologia , Doença de Parkinson/genética , Doença de Parkinson/microbiologia , Proteínas Quinases/deficiência , Proteínas Quinases/genética , Animais , Apresentação de Antígeno/imunologia , Autoantígenos/imunologia , Axônios/patologia , Linfócitos T CD8-Positivos/imunologia , Linfócitos T CD8-Positivos/patologia , Citrobacter rodentium/imunologia , Citrobacter rodentium/patogenicidade , Modelos Animais de Doenças , Neurônios Dopaminérgicos/imunologia , Neurônios Dopaminérgicos/patologia , Infecções por Enterobacteriaceae/imunologia , Infecções por Enterobacteriaceae/patologia , Feminino , Intestinos/imunologia , Intestinos/patologia , Levodopa/uso terapêutico , Masculino , Camundongos , Mitocôndrias/imunologia , Mitocôndrias/patologia , Neostriado/imunologia , Neostriado/microbiologia , Neostriado/patologia , Neostriado/fisiopatologia , Doença de Parkinson/tratamento farmacológico , Doença de Parkinson/fisiopatologia , Proteínas Quinases/imunologia , Ubiquitina-Proteína Ligases/deficiência , Ubiquitina-Proteína Ligases/genética , Ubiquitina-Proteína Ligases/imunologiaRESUMO
Autoimmunity is a normal physiological state that requires immunological homeostasis and surveillance, whereas necroptosis is a type of inflammatory cell death. When necroptosis occurs, various immune system cells must perform their appropriate duties to preserve immunological homeostasis, whether the consequence is expanding or limiting the inflammatory response and the pathological condition is cleared or progresses to the autoimmune disease stage. This article discusses necroptosis based on RIP homotypic interaction motif (RHIM) interaction under various physiological and pathological situations, with the RIPK1-RIPK3-MLKL necrosome serving as the regulatory core. In addition, the cell biology of necroptosis involved in autoimmunity and its application in autoimmune diseases were also reviewed.
Assuntos
Doenças Autoimunes , Autoimunidade , Necroptose , Proteína Serina-Treonina Quinases de Interação com Receptores , Humanos , Necroptose/imunologia , Autoimunidade/imunologia , Animais , Proteína Serina-Treonina Quinases de Interação com Receptores/imunologia , Proteína Serina-Treonina Quinases de Interação com Receptores/metabolismo , Doenças Autoimunes/imunologia , Proteínas Quinases/imunologia , Proteínas Quinases/metabolismoRESUMO
Receptor-interacting protein kinase 3 (RIPK3) and mixed lineage kinase domain-like pseudokinase (MLKL) are proteins that are critical for necroptosis, a mechanism of programmed cell death that is both activated when apoptosis is inhibited and thought to be antiviral. Here, we investigated the role of RIPK3 and MLKL in controlling the Orthopoxvirus ectromelia virus (ECTV), a natural pathogen of the mouse. We found that C57BL/6 (B6) mice deficient in RIPK3 (Ripk3-/-) or MLKL (Mlkl-/-) were as susceptible as wild-type (WT) B6 mice to ECTV lethality after low-dose intraperitoneal infection and were as resistant as WT B6 mice after ECTV infection through the natural footpad route. Additionally, after footpad infection, Mlkl-/- mice, but not Ripk3-/- mice, endured lower viral titers than WT mice in the draining lymph node (dLN) at three days postinfection and in the spleen or in the liver at seven days postinfection. Despite the improved viral control, Mlkl-/- mice did not differ from WT mice in the expression of interferons or interferon-stimulated genes or in the recruitment of natural killer (NK) cells and inflammatory monocytes (iMOs) to the dLN. Additionally, the CD8 T-cell responses in Mlkl-/- and WT mice were similar, even though in the dLNs of Mlkl-/- mice, professional antigen-presenting cells were more heavily infected. Finally, the histopathology in the livers of Mlkl-/- and WT mice at 7 dpi did not differ. Thus, the mechanism of the increased virus control by Mlkl-/- mice remains to be defined. IMPORTANCE The molecules RIPK3 and MLKL are required for necroptotic cell death, which is widely thought of as an antiviral mechanism. Here we show that C57BL/6 (B6) mice deficient in RIPK3 or MLKL are as susceptible as WT B6 mice to ECTV lethality after a low-dose intraperitoneal infection and are as resistant as WT B6 mice after ECTV infection through the natural footpad route. Mice deficient in MLKL are more efficient than WT mice at controlling virus loads in various organs. This improved viral control is not due to enhanced interferon, natural killer cell, or CD8 T-cell responses. Overall, the data indicate that deficiencies in the molecules that are critical to necroptosis do not necessarily result in worse outcomes following viral infection and may improve virus control.
Assuntos
Ectromelia Infecciosa , Animais , Camundongos , Vírus da Ectromelia , Ectromelia Infecciosa/imunologia , Interferons/metabolismo , Camundongos Endogâmicos C57BL , Necroptose/imunologia , Proteínas Quinases/genética , Proteínas Quinases/imunologia , Proteína Serina-Treonina Quinases de Interação com Receptores/genética , Proteína Serina-Treonina Quinases de Interação com Receptores/imunologiaRESUMO
Pseudorabies virus (PRV) has evolved various immune evasion mechanisms that target host antiviral immune responses. However, it is unclear whether and how PRV encoded proteins modulate the cGAS-STING axis for immune evasion. Here, we show that PRV tegument protein UL13 inhibits STING-mediated antiviral signaling via regulation of STING stability. Mechanistically, UL13 interacts with the CDN domain of STING and recruits the E3 ligase RING-finger protein 5 (RNF5) to promote K27-/K29-linked ubiquitination and degradation of STING. Consequently, deficiency of RNF5 enhances host antiviral immune responses triggered by PRV infection. In addition, mutant PRV lacking UL13 impaired in antagonism of STING-mediated production of type I IFNs and shows attenuated pathogenicity in mice. Our findings suggest that PRV UL13 functions as an antagonist of IFN signaling via a novel mechanism by targeting STING to persistently evade host antiviral responses.
Assuntos
Herpesvirus Suídeo 1 , Proteínas de Membrana , Proteínas Quinases , Pseudorraiva , Ubiquitina-Proteína Ligases , Animais , Herpesvirus Suídeo 1/imunologia , Imunidade Inata , Proteínas de Membrana/imunologia , Camundongos , Proteínas Quinases/imunologia , Pseudorraiva/imunologia , Ubiquitina-Proteína Ligases/imunologia , Proteínas Virais/imunologiaRESUMO
Arabidopsis CDG1 negatively regulates flg22- and chitin-triggered immunity by promoting FLS2 and CERK1 degradation and is partially required for bacterial effector AvrRpm1-induced RIN4 phosphorylation. Negative regulators play indispensable roles in pattern-triggered immunity in plants by preventing sustained immunity impeding growth. Here, we report Arabidopsis thaliana CONSTITUTIVE DIFFERENTIAL GROWTH1 (CDG1), a receptor-like cytoplasmic kinase VII member, as a negative regulator of bacterial flagellin/flg22- and fungal chitin-triggered immunity. CDG1 can interact with the flg22 receptor FLAGELLIN SENSITIVE2 (FLS2) and chitin co-receptor CHITIN ELICITOR RECEPTOR KINASE1 (CERK1). CDG1 overexpression impairs flg22 and chitin responses by promoting the degradation of FLS2 and CERK1. This process requires the kinase activity of MEK KINASE1 (MEKK1), but not the Plant U-Box (PUB) ubiquitin E3 ligases PUB12 and PUB13. Interestingly, the Pseudomonas syringae effector AvrRpm1 can induce CDG1 to interact with its host target RPM1-INTERACTING PROTEIN4 (RIN4), which depends on the ADP-ribosyl transferase activity of AvrRpm1. CDG1 is capable of phosphorylating RIN4 in vitro at multiple sites including Thr166 and the AvrRpm1-induced Thr166 phosphorylation of RIN4 is diminished in cdg1 null plants. Accordingly, CDG1 knockout attenuates AvrRpm1-induced hypersensitive response and increases the growth of AvrRpm1-secreting bacteria in plants. Unexpectedly, AvrRpm1 can also induce FLS2 depletion, which is fully dependent on RIN4 and partially dependent on CDG1, but does not require the kinase activity of MEKK1. Collectively, this study reveals previously unknown functions of CDG1 in both pattern-triggered immunity and effector-triggered susceptibility in plants.
Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/fisiologia , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Imunidade Vegetal/fisiologia , Proteínas Quinases/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/imunologia , Proteínas de Bactérias/metabolismo , Botrytis/patogenicidade , Quitina/metabolismo , Resistência à Doença , Regulação da Expressão Gênica de Plantas , MAP Quinase Quinase Quinases/genética , MAP Quinase Quinase Quinases/imunologia , MAP Quinase Quinase Quinases/metabolismo , Fosforilação , Doenças das Plantas/imunologia , Doenças das Plantas/microbiologia , Plantas Geneticamente Modificadas , Proteínas Quinases/genética , Proteínas Quinases/imunologia , Proteínas Serina-Treonina Quinases/genética , Proteínas Serina-Treonina Quinases/metabolismo , Ubiquitina-Proteína Ligases/metabolismoRESUMO
Stress granules (SGs) are dynamic structures that store cytosolic messenger ribonucleoproteins. SGs have recently been shown to serve as a platform for activating antiviral innate immunity; however, several pathogenic viruses suppress SG formation to evade innate immunity. In this study, we investigated the relationship between rabies virus (RABV) virulence and SG formation, using viral strains with different levels of virulence. We found that the virulent Nishigahara strain did not induce SG formation, but its avirulent offshoot, the Ni-CE strain, strongly induced SG formation. Furthermore, we demonstrated that the amino acid at position 95 in the RABV matrix protein (M95), a pathogenic determinant for the Nishigahara strain, plays a key role in inhibiting SG formation, followed by protein kinase R (PKR)-dependent phosphorylation of the α subunit of eukaryotic initiation factor 2α (eIF2α). M95 was also implicated in the accumulation of RIG-I, a viral RNA sensor protein, in SGs and in the subsequent acceleration of interferon induction. Taken together, our findings strongly suggest that M95-related inhibition of SG formation contributes to the pathogenesis of RABV by allowing the virus to evade the innate immune responses of the host. IMPORTANCE Rabies virus (RABV) is a neglected zoonotic pathogen that causes lethal infections in almost all mammalian hosts, including humans. Recently, RABV has been reported to induce intracellular formation of stress granules (SGs), also known as platforms that activate innate immune responses. However, the relationship between SG formation capacity and pathogenicity of RABV has remained unclear. In this study, by comparing two RABV strains with completely different levels of virulence, we found that the amino acid mutation from valine to alanine at position 95 of matrix protein (M95), which is known to be one of the amino acid mutations that determine the difference in virulence between the strains, plays a major role in SG formation. Importantly, M95 was involved in the accumulation of RIG-I in SGs and in promoting interferon induction. These findings are the first report of the effect of a single amino acid substitution associated with SGs on viral virulence.
Assuntos
Vírus da Raiva , Grânulos de Estresse , Proteínas da Matriz Viral , Aminoácidos/metabolismo , Animais , Fator de Iniciação 2 em Eucariotos/metabolismo , Humanos , Interferons/imunologia , Proteínas Quinases/imunologia , RNA Viral/metabolismo , Vírus da Raiva/genética , Vírus da Raiva/patogenicidade , Ribonucleoproteínas/metabolismo , Grânulos de Estresse/genética , Grânulos de Estresse/imunologia , Proteínas da Matriz Viral/genética , Proteínas da Matriz Viral/imunologia , Proteínas Virais/genética , Proteínas Virais/metabolismoRESUMO
Autosomal-recessive juvenile Parkinsonism (AR-JP) is caused by mutations in a number of PARK genes, in particular the genes encoding the E3 ubiquitin ligase Parkin (PARK2, also known as PRKN) and its upstream protein kinase PINK1 (also known as PARK6). PINK1 phosphorylates both ubiquitin and the ubiquitin-like domain of Parkin on structurally protected Ser65 residues, triggering mitophagy. Here we report a crystal structure of a nanobody-stabilized complex containing Pediculus humanus corporis (Ph)PINK1 bound to ubiquitin in the 'C-terminally retracted' (Ub-CR) conformation. The structure reveals many peculiarities of PINK1, including the architecture of the C-terminal region, and reveals how the N lobe of PINK1 binds ubiquitin via a unique insertion. The flexible Ser65 loop in the Ub-CR conformation contacts the activation segment, facilitating placement of Ser65 in a phosphate-accepting position. The structure also explains how autophosphorylation in the N lobe stabilizes structurally and functionally important insertions, and reveals the molecular basis of AR-JP-causing mutations, some of which disrupt ubiquitin binding.
Assuntos
Pediculus/enzimologia , Proteínas Quinases/química , Proteínas Quinases/metabolismo , Ubiquitina/química , Ubiquitina/metabolismo , Animais , Sítios de Ligação , Cristalografia por Raios X , Mitofagia , Modelos Moleculares , Mutação , Fosforilação , Proteínas Quinases/genética , Proteínas Quinases/imunologia , Anticorpos de Cadeia Única/química , Anticorpos de Cadeia Única/imunologiaRESUMO
Programmed necrotic cell death induced by the tumor necrosis factor alpha (TNF-α) family of cytokines is dependent on a kinase cascade consisting of receptor-interacting kinases RIP1 and RIP3. How these kinase activities cause cells to die by necrosis is not known. The mixed lineage kinase domain-like protein MLKL is a functional RIP3 substrate that binds to RIP3 through its kinase-like domain but lacks kinase activity of its own. RIP3 phosphorylates MLKL at the T357 and S358 sites. Reported here is the development of a monoclonal antibody that specifically recognizes phosphorylated MLKL in cells dying of this pathway and in human liver biopsy samples from patients suffering from drug-induced liver injury. The phosphorylated MLKL forms an oligomer that binds to phosphatidylinositol lipids and cardiolipin. This property allows MLKL to move from the cytosol to the plasma and intracellular membranes, where it directly disrupts membrane integrity, resulting in necrotic death.
Assuntos
Membrana Celular/enzimologia , Proteínas Quinases/metabolismo , Proteína Serina-Treonina Quinases de Interação com Receptores/metabolismo , Anticorpos Monoclonais/imunologia , Sítios de Ligação , Cardiolipinas/metabolismo , Membrana Celular/patologia , Doença Hepática Induzida por Substâncias e Drogas/enzimologia , Doença Hepática Induzida por Substâncias e Drogas/patologia , Células HT29 , Células HeLa , Humanos , Membranas Intracelulares/enzimologia , Membranas Intracelulares/patologia , Fígado/enzimologia , Fígado/patologia , Lipídeos de Membrana/metabolismo , Necrose , Fosforilação , Conformação Proteica , Proteínas Quinases/genética , Proteínas Quinases/imunologia , Transporte Proteico , Interferência de RNA , Proteína Serina-Treonina Quinases de Interação com Receptores/genética , Transdução de Sinais , Especificidade por Substrato , Fatores de Tempo , TransfecçãoRESUMO
The rapid production of reactive oxygen species (ROS) burst is a conserved signaling output in immunity across kingdoms. In plants, perception of pathogen-associated molecular patterns (PAMPs) by surface-localized pattern recognition receptors (PRRs) activates the NADPH oxidase RBOHD by hitherto unknown mechanisms. Here, we show that RBOHD exists in complex with the receptor kinases EFR and FLS2, which are the PRRs for bacterial EF-Tu and flagellin, respectively. The plasma-membrane-associated kinase BIK1, which is a direct substrate of the PRR complex, directly interacts with and phosphorylates RBOHD upon PAMP perception. BIK1 phosphorylates different residues than calcium-dependent protein kinases, and both PAMP-induced BIK1 activation and BIK1-mediated phosphorylation of RBOHD are calcium independent. Importantly, phosphorylation of these residues is critical for the PAMP-induced ROS burst and antibacterial immunity. Our study reveals a rapid regulatory mechanism of a plant RBOH, which occurs in parallel with and is essential for its paradigmatic calcium-based regulation.
Assuntos
Proteínas de Arabidopsis/imunologia , Proteínas de Arabidopsis/metabolismo , Arabidopsis/enzimologia , Imunidade Inata , NADPH Oxidases/imunologia , Nicotiana/enzimologia , Imunidade Vegetal , Proteínas Serina-Treonina Quinases/metabolismo , Sequência de Aminoácidos , Arabidopsis/genética , Arabidopsis/imunologia , Arabidopsis/microbiologia , Proteínas de Arabidopsis/genética , Linhagem Celular , Ativação Enzimática , Flagelina/imunologia , Flagelina/metabolismo , Regulação Enzimológica da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Ligantes , Dados de Sequência Molecular , Complexos Multienzimáticos , NADPH Oxidases/genética , Fator Tu de Elongação de Peptídeos/imunologia , Fator Tu de Elongação de Peptídeos/metabolismo , Fosforilação , Estômatos de Plantas/imunologia , Estômatos de Plantas/metabolismo , Proteínas Quinases/imunologia , Proteínas Quinases/metabolismo , Proteínas Serina-Treonina Quinases/genética , Espécies Reativas de Oxigênio/metabolismo , Receptores Imunológicos/metabolismo , Receptores de Reconhecimento de Padrão/imunologia , Receptores de Reconhecimento de Padrão/metabolismo , Transdução de Sinais , Nicotiana/genética , Nicotiana/imunologia , Nicotiana/microbiologiaRESUMO
Community-acquired pneumonia is the most common type of pneumonia and remains a leading cause of morbidity and mortality worldwide. Although many different pathogens can contribute to pneumonia, Streptococcus pneumoniae is one of the common bacterial pathogens that underlie community-acquired pneumonia. RIPK3 (receptor-interacting protein kinase 3) is widely recognized as a key modulator of inflammation and cell death. To elucidate a potential role of RIPK3 in pneumonia, we examined plasma from healthy control subjects and patients positive for streptococcal pneumonia. In human studies, RIPK3 protein concentrations were significantly elevated and were identified as a potential plasma marker of pneumococcal pneumonia. To expand these findings, we used an in vivo murine model of pneumococcal pneumonia to demonstrate that RIPK3 deficiency leads to reduced bacterial clearance, severe pathological damage, and high mortality. Our results illustrated that RIPK3 forms a complex with RIPK1, MLKL (mixed-lineage kinase domain-like protein), and MCU (mitochondrial calcium uniporter) to induce mitochondrial calcium uptake and mitochondrial reactive oxygen species(mROS) production during S. pneumoniae infection. In macrophages, RIPK3 initiated necroptosis via the mROS-mediated mitochondrial permeability transition pore opening and NLRP3 inflammasome activation via the mROS-AKT pathway to protect against S. pneumoniae. In conclusion, our study demonstrated a mechanism by which RIPK3-initiated necroptosis is essential for host defense against S. pneumoniae.
Assuntos
Macrófagos Alveolares/imunologia , Mitocôndrias/imunologia , Pneumonia Pneumocócica/imunologia , Proteínas Quinases/imunologia , Proteína Serina-Treonina Quinases de Interação com Receptores/imunologia , Streptococcus pneumoniae/patogenicidade , Idoso , Animais , Canais de Cálcio/genética , Canais de Cálcio/imunologia , Estudos de Casos e Controles , Modelos Animais de Doenças , Feminino , Regulação da Expressão Gênica , Humanos , Inflamassomos/genética , Inflamassomos/imunologia , Macrófagos Alveolares/patologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Pessoa de Meia-Idade , Mitocôndrias/patologia , Poro de Transição de Permeabilidade Mitocondrial/imunologia , Poro de Transição de Permeabilidade Mitocondrial/metabolismo , Proteína 3 que Contém Domínio de Pirina da Família NLR/genética , Proteína 3 que Contém Domínio de Pirina da Família NLR/imunologia , Necroptose/genética , Necroptose/imunologia , Pneumonia Pneumocócica/complicações , Pneumonia Pneumocócica/microbiologia , Proteínas Quinases/genética , Proteínas Proto-Oncogênicas c-akt/genética , Proteínas Proto-Oncogênicas c-akt/imunologia , Espécies Reativas de Oxigênio/imunologia , Espécies Reativas de Oxigênio/metabolismo , Proteína Serina-Treonina Quinases de Interação com Receptores/genética , Transdução de Sinais , Streptococcus pneumoniae/imunologiaRESUMO
Mitochondria have emerged as important signaling organelles where intracellular perturbations are integrated and, consequently, intracellular signaling pathways are modulated to execute appropriate cellular functions. MAVS (mitochondrial antiviral signaling protein) represents such an example that functions as a platform molecule to mediate mitochondrial innate immune signaling. Recently, multimeric aggregation of MAVS has been identified as a key molecular process for its signaling. The underlying mechanisms to regulate this, however, are still incompletely understood. We hypothesized that PINK1 (PTEN-induced kinase 1) plays an important role in the regulation of multimeric MAVS aggregation and its consequent pathobiology. To test whether PINK1 interacts with MAVS, bimolecular fluorescence complementation analysis and IP were performed. RLH (RIG-I-like helicase) and NLRP3 inflammasome signaling were evaluated by in vitro assay. In vivo functional significance of PINK1 in the regulation of MAVS signaling was evaluated from both murine modeling of influenza viral infection and bleomycin-induced experimental pulmonary fibrosis, wherein MAVS plays important roles. Multimeric MAVS aggregation was induced by mitochondria dysfunction, and, during this event, the stabilized PINK1 interacted physically with MAVS and antagonized multimeric MAVS aggregation. Accordingly, the MAVS-mediated antiviral innate immune and NLRP3 inflammasome signaling were enhanced in PINK1 deficiency. In addition, in vivo studies revealed that MAVS-mediated pulmonary antiviral innate immune responses and fibrotic responses after bleomycin injury were enhanced in PINK1 deficiency. In conclusion, these results establish a new role of PINK1 in the regulation of MAVS signaling and the consequent pulmonary pathobiology.
Assuntos
Proteínas Adaptadoras de Transdução de Sinal/genética , Mitocôndrias/metabolismo , Infecções por Orthomyxoviridae/genética , Proteínas Quinases/genética , Fibrose Pulmonar/genética , Transdução de Sinais/genética , Proteínas Adaptadoras de Transdução de Sinal/deficiência , Proteínas Adaptadoras de Transdução de Sinal/imunologia , Animais , Bleomicina/administração & dosagem , Células Epiteliais/imunologia , Células Epiteliais/metabolismo , Células Epiteliais/virologia , Regulação da Expressão Gênica , Células HEK293 , Humanos , Imunidade Inata , Inflamassomos/genética , Inflamassomos/imunologia , Vírus da Influenza A/imunologia , Vírus da Influenza A/patogenicidade , Pulmão/imunologia , Pulmão/virologia , Camundongos , Camundongos Knockout , Mitocôndrias/imunologia , Proteína 3 que Contém Domínio de Pirina da Família NLR/genética , Proteína 3 que Contém Domínio de Pirina da Família NLR/imunologia , Infecções por Orthomyxoviridae/imunologia , Infecções por Orthomyxoviridae/virologia , Peroxissomos/imunologia , Peroxissomos/metabolismo , Agregados Proteicos/genética , Ligação Proteica , Proteínas Quinases/deficiência , Proteínas Quinases/imunologia , Fibrose Pulmonar/induzido quimicamente , Fibrose Pulmonar/imunologia , Fibrose Pulmonar/patologia , Transdução de Sinais/imunologiaRESUMO
Cooperation between different innate signaling pathways induced by pattern-recognition receptors (PRRs) on dendritic cells (DCs) is crucial for tailoring adaptive immunity to pathogens. Here we show that carbohydrate-specific signaling through the C-type lectin DC-SIGN tailored cytokine production in response to distinct pathogens. DC-SIGN was constitutively associated with a signalosome complex consisting of the scaffold proteins LSP1, KSR1 and CNK and the kinase Raf-1. Mannose-expressing Mycobacterium tuberculosis and human immunodeficiency virus type 1 (HIV-1) induced the recruitment of effector proteins to the DC-SIGN signalosome to activate Raf-1, whereas fucose-expressing pathogens such as Helicobacter pylori actively dissociated the KSR1-CNK-Raf-1 complex from the DC-SIGN signalosome. This dynamic regulation of the signalosome by mannose- and fucose-expressing pathogens led to the enhancement or suppression of proinflammatory responses, respectively. Our study reveals another level of plasticity in tailoring adaptive immunity to pathogens.
Assuntos
Carboidratos/imunologia , Moléculas de Adesão Celular/imunologia , HIV-1/imunologia , Helicobacter pylori/imunologia , Lectinas Tipo C/imunologia , Mycobacterium tuberculosis/imunologia , Receptores de Superfície Celular/imunologia , Transdução de Sinais/imunologia , Western Blotting , Moléculas de Adesão Celular/metabolismo , Citocinas/biossíntese , Citocinas/imunologia , Células Dendríticas/imunologia , Células Dendríticas/metabolismo , Ensaio de Imunoadsorção Enzimática , Citometria de Fluxo , Fucose/imunologia , Humanos , Lectinas Tipo C/metabolismo , Manose/imunologia , Proteínas dos Microfilamentos/imunologia , Proteínas dos Microfilamentos/metabolismo , Proteínas Quinases/imunologia , Proteínas Quinases/metabolismo , Proteínas Proto-Oncogênicas c-raf/imunologia , Proteínas Proto-Oncogênicas c-raf/metabolismo , Receptores de Superfície Celular/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase ReversaRESUMO
Plant protein kinases form redundant signaling pathways to perceive microbial pathogens and activate immunity. Bacterial pathogens repress cellular immune responses by secreting effectors, some of which bind and inhibit multiple host kinases. To understand how broadly bacterial effectors may bind protein kinases and the function of these kinase interactors, we first tested kinase-effector (K-E) interactions using the Pseudomonas syringae pv. tomato-tomato pathosystem. We tested interactions between five individual effectors (HopAI1, AvrPto, HopA1, HopM1, and HopAF1) and 279 tomato kinases in tomato cells. Over half of the tested kinases interacted with at least one effector, and 48% of these kinases interacted with more than three effectors, suggesting a role in the defense. Next, we characterized the role of select multi-effector-interacting kinases and revealed their roles in basal resistance, effector-triggered immunity (ETI), or programmed cell death (PCD). The immune function of several of these kinases was only detectable in the presence of effectors, suggesting that these kinases are critical when particular cell functions are perturbed or that their role is typically masked. To visualize the kinase networks underlying the cellular responses, we derived signal-specific networks. A comparison of the networks revealed a limited overlap between ETI and basal immunity networks. In addition, the basal immune network complexity increased when exposed to some of the effectors. The networks were used to successfully predict the role of a new set of kinases in basal immunity. Our work indicates the complexity of the larger kinase-based defense network and demonstrates how virulence- and avirulence-associated bacterial effectors alter sectors of the defense network.
Assuntos
Proteínas Quinases/fisiologia , Solanum lycopersicum/imunologia , Fatores de Virulência/imunologia , Proteínas de Bactérias/metabolismo , Interações Hospedeiro-Patógeno , Solanum lycopersicum/genética , Doenças das Plantas/microbiologia , Imunidade Vegetal/fisiologia , Proteínas de Plantas/metabolismo , Proteínas Quinases/imunologia , Pseudomonas syringae/patogenicidade , Transdução de Sinais , VirulênciaRESUMO
Asthma represents an inflammatory airway disease related to the induction of airway eosinophilia, mucus overproduction, and bronchial hyperresponsiveness. This study explored the effects of microRNA-423 (miR-423) on mitophagy and inflammation in asthmatic mice challenged with house dust mites (HDMs) and rhinovirus (RV). By searching for differentially expressed miRNAs in the GSE25230 microarray, miR-423 was identified as our target. Moreover, miR-423 was expressed at low levels in the lung tissues from patients with asthma, and agomiR-423 significantly inhibited RV-induced inflammatory injury and activation of inflammasome signaling in mouse lung tissues. Additionally, miR-423 downregulated the expression of IL-1ß/NLRP3/Caspase-1 inflammasome signaling by targeting phosphatase and tensin homolog-induced putative kinase 1 (PINK1). Furthermore, luciferase reporter experiments and ChIP-qPCR assays revealed that estrogen receptor 2 (ESR2) transcriptionally repressed miR-423 expression by coordinating with H3K9me2 modification of the miR-423 promoter histone. Overall, ESR2 synergized with the H3K9me2 modification of the miR-423 promoter histone to transcriptionally repress miR-423 expression and increase PINK1 expression in lung tissues, resulting in asthma exacerbation.
Assuntos
Asma/genética , Receptor beta de Estrogênio/genética , MicroRNAs , Proteínas Quinases/genética , Animais , Antígenos de Dermatophagoides , Asma/imunologia , Linhagem Celular , Citocinas/genética , Citocinas/imunologia , Feminino , Humanos , Inflamassomos/genética , Inflamassomos/imunologia , Pulmão/imunologia , Masculino , Camundongos Endogâmicos C57BL , Camundongos Knockout , Mitofagia , Proteína 3 que Contém Domínio de Pirina da Família NLR/genética , Proteína 3 que Contém Domínio de Pirina da Família NLR/imunologia , Infecções por Picornaviridae/genética , Infecções por Picornaviridae/imunologia , Proteínas Quinases/imunologia , Rhinovirus , Transcrição GênicaRESUMO
INTRODUCTION: Mitochondrial dysfunction is a common denominator of neuroinflammation recognized by neuronal oxidative stress-mediated apoptosis that is well recognized by common intracellular molecular pathway-interlinked neuroinflammation and mitochondrial oxidative stress, a feature of epileptogenesis. In addition, the neuronal damage in the epileptic brain corroborated the concept of brain injury-mediated neuroinflammation, further providing an interlink between inflammation, mitochondrial dysfunction, and oxidative stress in epilepsy. MATERIALS AND METHODS: A systematic literature review of Bentham, Scopus, PubMed, Medline, and EMBASE (Elsevier) databases was carried out to provide evidence of preclinical and clinically used drugs targeting such nuclear, cytosolic, and mitochondrial proteins suggesting that the correlation of mechanisms linked to neuroinflammation has been elucidated in the current review. Despite that, the evidence of elevated levels of inflammatory mediators and pro-apoptotic protein levels can provide the correlation of inflammatory responses often concerned with hyperexcitability attributing to the fact that mitochondrial redox mechanisms and higher susceptibilities to neuroinflammation result from repetitive recurring epileptic seizures. Therefore, providing an understanding of seizure-induced pathological changes read by activating neuroinflammatory cascades like NF-kB, RIPK, MAPK, ERK, JNK, and JAK-STAT signaling further related to mitochondrial damage promoting hyperexcitability. CONCLUSION: The current review highlights the further opportunity for establishing therapeutic interventions underlying the apparent correlation of neuroinflammation mediated mitochondrial oxidative stress might contribute to common intracellular mechanisms underlying a future prospective of drug treatment targeting mitochondrial dysfunction linked to the neuroinflammation in epilepsy.
Assuntos
Epilepsia/imunologia , Mitocôndrias/imunologia , Doenças Neuroinflamatórias/imunologia , Animais , Morte Celular , Humanos , Inflamassomos/imunologia , Neurônios/imunologia , PPAR gama/imunologia , Fosfatidilinositol 3-Quinase/imunologia , Proteínas Quinases/imunologia , Proteínas Proto-Oncogênicas c-akt/imunologia , Proteínas Proto-Oncogênicas c-bcl-2/imunologia , Fatores de Transcrição STAT/imunologia , Proteína Desacopladora 2/imunologiaRESUMO
Invasive microbes causing diseases such as sudden oak death negatively affect ecosystems and economies around the world. The deployment of resistant genotypes for combating introduced diseases typically relies on breeding programs that can take decades to complete. To demonstrate how this process can be accelerated, we employed a genome-wide association mapping of ca 1,000 resequenced Populus trichocarpa trees individually challenged with Sphaerulina musiva, an invasive fungal pathogen. Among significant associations, three loci associated with resistance were identified and predicted to encode one putative membrane-bound L-type receptor-like kinase and two receptor-like proteins. A susceptibility-associated locus was predicted to encode a putative G-type D-mannose-binding receptor-like kinase. Multiple lines of evidence, including allele analysis, transcriptomics, binding assays, and overexpression, support the hypothesized function of these candidate genes in the P. trichocarpa response to S. musiva.