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1.
Cell ; 187(15): 4061-4077.e17, 2024 Jul 25.
Artigo em Inglês | MEDLINE | ID: mdl-38878777

RESUMO

NLRs constitute a large, highly conserved family of cytosolic pattern recognition receptors that are central to health and disease, making them key therapeutic targets. NLRC5 is an enigmatic NLR with mutations associated with inflammatory and infectious diseases, but little is known about its function as an innate immune sensor and cell death regulator. Therefore, we screened for NLRC5's role in response to infections, PAMPs, DAMPs, and cytokines. We identified that NLRC5 acts as an innate immune sensor to drive inflammatory cell death, PANoptosis, in response to specific ligands, including PAMP/heme and heme/cytokine combinations. NLRC5 interacted with NLRP12 and PANoptosome components to form a cell death complex, suggesting an NLR network forms similar to those in plants. Mechanistically, TLR signaling and NAD+ levels regulated NLRC5 expression and ROS production to control cell death. Furthermore, NLRC5-deficient mice were protected in hemolytic and inflammatory models, suggesting that NLRC5 could be a potential therapeutic target.


Assuntos
Inflamação , Peptídeos e Proteínas de Sinalização Intracelular , NAD , Animais , Camundongos , Inflamação/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/genética , NAD/metabolismo , Humanos , Imunidade Inata , Camundongos Endogâmicos C57BL , Espécies Reativas de Oxigênio/metabolismo , Camundongos Knockout , Transdução de Sinais , Células HEK293 , Inflamassomos/metabolismo , Proteínas Reguladoras de Apoptose/metabolismo , Proteínas Reguladoras de Apoptose/genética , Receptores Toll-Like/metabolismo , Masculino , Citocinas/metabolismo , Proteínas de Ligação ao Cálcio
2.
Cell ; 186(13): 2783-2801.e20, 2023 06 22.
Artigo em Inglês | MEDLINE | ID: mdl-37267949

RESUMO

Cytosolic innate immune sensors are critical for host defense and form complexes, such as inflammasomes and PANoptosomes, that induce inflammatory cell death. The sensor NLRP12 is associated with infectious and inflammatory diseases, but its activating triggers and roles in cell death and inflammation remain unclear. Here, we discovered that NLRP12 drives inflammasome and PANoptosome activation, cell death, and inflammation in response to heme plus PAMPs or TNF. TLR2/4-mediated signaling through IRF1 induced Nlrp12 expression, which led to inflammasome formation to induce maturation of IL-1ß and IL-18. The inflammasome also served as an integral component of a larger NLRP12-PANoptosome that drove inflammatory cell death through caspase-8/RIPK3. Deletion of Nlrp12 protected mice from acute kidney injury and lethality in a hemolytic model. Overall, we identified NLRP12 as an essential cytosolic sensor for heme plus PAMPs-mediated PANoptosis, inflammation, and pathology, suggesting that NLRP12 and molecules in this pathway are potential drug targets for hemolytic and inflammatory diseases.


Assuntos
Inflamassomos , Moléculas com Motivos Associados a Patógenos , Animais , Camundongos , Inflamassomos/metabolismo , Heme , Inflamação , Piroptose , Peptídeos e Proteínas de Sinalização Intracelular
3.
Cell ; 185(4): 614-629.e21, 2022 02 17.
Artigo em Inglês | MEDLINE | ID: mdl-35148840

RESUMO

Activation of the innate immune system via pattern recognition receptors (PRRs) is key to generate lasting adaptive immunity. PRRs detect unique chemical patterns associated with invading microorganisms, but whether and how the physical properties of PRR ligands influence the development of the immune response remains unknown. Through the study of fungal mannans, we show that the physical form of PRR ligands dictates the immune response. Soluble mannans are immunosilent in the periphery but elicit a potent pro-inflammatory response in the draining lymph node (dLN). By modulating the physical form of mannans, we developed a formulation that targets both the periphery and the dLN. When combined with viral glycoprotein antigens, this mannan formulation broadens epitope recognition, elicits potent antigen-specific neutralizing antibodies, and confers protection against viral infections of the lung. Thus, the physical properties of microbial ligands determine the outcome of the immune response and can be harnessed for vaccine development.


Assuntos
Adjuvantes Imunológicos/farmacologia , Antígenos Virais/imunologia , Candida albicans/química , Mananas/imunologia , Hidróxido de Alumínio/química , Animais , Anticorpos Neutralizantes/imunologia , Especificidade de Anticorpos/imunologia , Linfócitos B/imunologia , COVID-19/imunologia , COVID-19/prevenção & controle , COVID-19/virologia , Chlorocebus aethiops , Epitopos/imunologia , Imunidade Inata , Imunização , Inflamação/patologia , Interferons/metabolismo , Lectinas Tipo C/metabolismo , Ligantes , Pulmão/imunologia , Pulmão/patologia , Pulmão/virologia , Linfonodos/imunologia , Linfonodos/metabolismo , Macrófagos/metabolismo , Camundongos Endogâmicos C57BL , Seios Paranasais/metabolismo , Subunidades Proteicas/metabolismo , Lectina 1 Semelhante a Ig de Ligação ao Ácido Siálico/metabolismo , Solubilidade , Glicoproteína da Espícula de Coronavírus/metabolismo , Linfócitos T/imunologia , Fator de Transcrição RelB/metabolismo , Células Vero , beta-Glucanas/metabolismo
4.
Immunity ; 57(4): 674-699, 2024 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-38599165

RESUMO

Nucleotide-binding oligomerization domain (NOD)-like receptors, also known as nucleotide-binding leucine-rich repeat receptors (NLRs), are a family of cytosolic pattern recognition receptors that detect a wide variety of pathogenic and sterile triggers. Activation of specific NLRs initiates pro- or anti-inflammatory signaling cascades and the formation of inflammasomes-multi-protein complexes that induce caspase-1 activation to drive inflammatory cytokine maturation and lytic cell death, pyroptosis. Certain NLRs and inflammasomes act as integral components of larger cell death complexes-PANoptosomes-driving another form of lytic cell death, PANoptosis. Here, we review the current understanding of the evolution, structure, and function of NLRs in health and disease. We discuss the concept of NLR networks and their roles in driving cell death and immunity. An improved mechanistic understanding of NLRs may provide therapeutic strategies applicable across infectious and inflammatory diseases and in cancer.


Assuntos
Inflamassomos , Receptores de Reconhecimento de Padrão , Inflamassomos/metabolismo , Piroptose , Imunidade Inata , Nucleotídeos
5.
Cell ; 171(4): 809-823.e13, 2017 Nov 02.
Artigo em Inglês | MEDLINE | ID: mdl-29056340

RESUMO

Constitutive cell-autonomous immunity in metazoans predates interferon-inducible immunity and comprises primordial innate defense. Phagocytes mobilize interferon-inducible responses upon engagement of well-characterized signaling pathways by pathogen-associated molecular patterns (PAMPs). The signals controlling deployment of constitutive cell-autonomous responses during infection have remained elusive. Vita-PAMPs denote microbial viability, signaling the danger of cellular exploitation by intracellular pathogens. We show that cyclic-di-adenosine monophosphate in live Gram-positive bacteria is a vita-PAMP, engaging the innate sensor stimulator of interferon genes (STING) to mediate endoplasmic reticulum (ER) stress. Subsequent inactivation of the mechanistic target of rapamycin mobilizes autophagy, which sequesters stressed ER membranes, resolves ER stress, and curtails phagocyte death. This vita-PAMP-induced ER-phagy additionally orchestrates an interferon response by localizing ER-resident STING to autophagosomes. Our findings identify stress-mediated ER-phagy as a cell-autonomous response mobilized by STING-dependent sensing of a specific vita-PAMP and elucidate how innate receptors engage multilayered homeostatic mechanisms to promote immunity and survival after infection.


Assuntos
Bactérias Gram-Positivas/fisiologia , Infecções por Bactérias Gram-Positivas/imunologia , Proteínas de Membrana/metabolismo , Fagócitos/imunologia , Animais , Autofagia , Retículo Endoplasmático/metabolismo , Estresse do Retículo Endoplasmático , Feminino , Masculino , Camundongos , Moléculas com Motivos Associados a Patógenos/metabolismo , Serina-Treonina Quinases TOR/metabolismo
6.
EMBO J ; 41(23): e107257, 2022 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-36314733

RESUMO

Plant immunity is tightly controlled by a complex and dynamic regulatory network, which ensures optimal activation upon detection of potential pathogens. Accordingly, each component of this network is a potential target for manipulation by pathogens. Here, we report that RipAC, a type III-secreted effector from the bacterial pathogen Ralstonia solanacearum, targets the plant E3 ubiquitin ligase PUB4 to inhibit pattern-triggered immunity (PTI). PUB4 plays a positive role in PTI by regulating the homeostasis of the central immune kinase BIK1. Before PAMP perception, PUB4 promotes the degradation of non-activated BIK1, while after PAMP perception, PUB4 contributes to the accumulation of activated BIK1. RipAC leads to BIK1 degradation, which correlates with its PTI-inhibitory activity. RipAC causes a reduction in pathogen-associated molecular pattern (PAMP)-induced PUB4 accumulation and phosphorylation. Our results shed light on the role played by PUB4 in immune regulation, and illustrate an indirect targeting of the immune signalling hub BIK1 by a bacterial effector.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Ubiquitina-Proteína Ligases/genética , Ubiquitina-Proteína Ligases/metabolismo , Moléculas com Motivos Associados a Patógenos/metabolismo , Imunidade Vegetal/genética , Doenças das Plantas , Proteínas Serina-Treonina Quinases/genética
7.
Methods ; 230: 68-79, 2024 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-39097177

RESUMO

Beta glucans are found in many natural sources, however, only Baker's Yeast Beta Glucan (BYBG) has been well documented to have structure-function effects that are associated with improved innate immune response to stressors (e.g., exercise, infection, etc.). The purpose was to identify a BYBG-associated mRNA expression pattern following exercise. Participants gave IRB-approved consent and were randomized to BYBG (Wellmune®; N=9) or Placebo (maltodextrin; N=10) for 6-weeks prior to performing 90 min of whole-body exercise. Paxgene blood samples were collected prior to exercise (PRE), after exercise (POST), two hours after exercise (2H), and four hours after exercise (4H). Total RNA was isolated and analyzed for the expression of 770 innate immune response mRNA (730 mRNA targets; 40 housekeepers/controls; Nanostring nCounter). The raw data were normalized against housekeeping controls and expressed as Log2 fold change from PRE for a given condition. Significance was set at p < 0.05 with adjustments for multiple comparisons and false discovery rate. We identified 47 mRNA whose expression was changed after exercise with BYBG and classified them to four functional pathways: 1) Immune Cell Maturation (8 mRNA), 2) Immune Response and Function (5 mRNA), 3) Pattern Recognition Receptors and DAMP or PAMP Detection (25 mRNA), and 4) Detection and Resolution of Tissue Damage (9 mRNA). The identified mRNA whose expression was altered after exercise with BYBG may represent an innate immune response pattern and supports previous conclusions that BYBG improves immune response to a future sterile inflammation or infection.


Assuntos
Exercício Físico , Imunidade Inata , RNA Mensageiro , Saccharomyces cerevisiae , beta-Glucanas , Humanos , Imunidade Inata/efeitos dos fármacos , Imunidade Inata/genética , beta-Glucanas/farmacologia , beta-Glucanas/administração & dosagem , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Exercício Físico/fisiologia , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/imunologia , Masculino , Suplementos Nutricionais , Adulto , Feminino , Adulto Jovem , Regulação da Expressão Gênica/efeitos dos fármacos
8.
J Neurochem ; 168(9): 2935-2955, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-38943350

RESUMO

Astrocytes provide metabolic support to neurons, maintain ionic and water homeostasis, and uptake and recycle neurotransmitters. After exposure to the prototypical PAMP lipopolysaccharide (LPS), reactive astrocytes increase the expression of pro-inflammatory genes, facilitating neurodegeneration. In this study, we analyzed the expression of homeostatic genes in astrocytes exposed to LPS and identified the epigenetic factors contributing to the suppression of homeostatic genes in reactive astrocytes. Primary astrocytic cultures were acutely exposed to LPS and allowed to recover for 24, 72 h, and 7 days. As expected, LPS exposure induced reactive astrogliosis and increased the expression of pro-inflammatory IL-1B and IL-6. Interestingly, the acute exposure resulted in persistent hypermethylation of astroglial DNA. Similar hypermethylation was observed in highly reactive astrocytes from the traumatic brain injury (TBI) penumbra in vivo. Hypermethylation was accompanied by decreased expression of homeostatic genes including LDHA and Scl16a1 (MCT1) both involved in the lactate shuttle to neurons; glutamine synthase (GS) responsible for glutamate processing; Kcnj10 (Kir4.1) important for K+ homeostasis, and the water channel aquaporin-4 (Aqp4). Furthermore, the master regulator of DNA methylation, MAFG-1, as well as DNA methyl transferases DNMT1 and DNMT3a were overexpressed. The downregulation of homeostatic genes correlated with increased methylation of CpG islands in their promoters, as assessed by methylation-sensitive PCR and increased DNMT3a binding to the GS promoter. Treatment with decitabine, a DNMT inhibitor, prevented the LPS- and the HMGB-1-induced downregulation of homeostatic genes. Decitabine treatment also prevented the neurotoxic effects of these astrocytes in primary cortical cultures. In summary, our findings reveal that the pathological remodeling of reactive astrocytes encompasses not only the pro-inflammatory response but, significantly, also entails a long-term suppression of homeostatic gene expression with methylation of crucial CpG islands within their promoters.


Assuntos
Astrócitos , Metilação de DNA , Regulação para Baixo , Homeostase , Astrócitos/metabolismo , Astrócitos/efeitos dos fármacos , Astrócitos/patologia , Metilação de DNA/efeitos dos fármacos , Animais , Homeostase/efeitos dos fármacos , Regulação para Baixo/efeitos dos fármacos , Células Cultivadas , Lipopolissacarídeos/farmacologia , Masculino , Camundongos , Lesões Encefálicas Traumáticas/patologia , Lesões Encefálicas Traumáticas/metabolismo , Lesões Encefálicas Traumáticas/genética , Ratos , Camundongos Endogâmicos C57BL
9.
Planta ; 260(5): 108, 2024 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-39333439

RESUMO

MAIN CONCLUSION: Despite modulating senescence and drought responses, the GmERD15-like subfamily members are differentially induced by multiple stresses and diverge partially in stress signaling functions. The PAM2 motif represents a binding site for poly (A)-binding proteins (PABPs), often associated with RNA metabolism regulation. The PAM2-containing protein ERD15 stands out as a critical regulator of diverse stress responses in plants. Despite the relevance of the PAM2 motif, a comprehensive analysis of the PAM2 superfamily and ERD15-like subfamily in the plant kingdom is lacking. Here, we provide an extensive in silico analysis of the PAM2 superfamily and the ERD15-like subfamily in soybean, using Arabidopsis and rice sequences as prototypes. The Glycine max ERD15-like subfamily members were clustered in pairs, likely originating from DNA-based gene duplication, as the paralogs display high sequence conservation, similar exon/intron genome organization, and are undergoing purifying selection. Complementation analyses of an aterd15 mutant demonstrated that the plant ERD15-like subfamily members are functionally redundant in response to drought, osmotic stress, and dark-induced senescence. Nevertheless, the soybean members displayed differential expression profiles, biochemical activity, and subcellular localization, consistent with functional diversification. The expression profiles of Glyma04G138600 under salicylic acid (SA) and abscisic acid (ABA) treatments differed oppositely from those of the other GmERD15-like genes. Abiotic stress-induced coexpression analysis with soybean PABPs showed that Glyma04G138600 was clustered separately from other GmERD15s. In contrast to the AtERD15 stress-induced nuclear redistribution, Glyma04G138600 and Glyma02G260800 localized to the cytoplasm, while Glyma03G131900 fractionated between the cytoplasm and nucleus under normal and stress conditions. These data collectively indicate that despite modulating senescence and drought responses, the GmERD15-like subfamily members are differentially induced by multiple stresses and may diverge partially in stress signaling functions.


Assuntos
Arabidopsis , Regulação da Expressão Gênica de Plantas , Glycine max , Proteínas de Plantas , Estresse Fisiológico , Glycine max/genética , Glycine max/fisiologia , Glycine max/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Estresse Fisiológico/genética , Arabidopsis/genética , Secas , Oryza/genética , Oryza/metabolismo , Oryza/fisiologia , Filogenia , Família Multigênica
10.
New Phytol ; 242(1): 170-191, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38348532

RESUMO

Plants activate immunity upon recognition of pathogen-associated molecular patterns. Although phytopathogens have evolved a set of effector proteins to counteract plant immunity, some effectors are perceived by hosts and induce immune responses. Here, we show that two secreted ribonuclease effectors, SRN1 and SRN2, encoded in a phytopathogenic fungus, Colletotrichum orbiculare, induce cell death in a signal peptide- and catalytic residue-dependent manner, when transiently expressed in Nicotiana benthamiana. The pervasive presence of SRN genes across Colletotrichum species suggested the conserved roles. Using a transient gene expression system in cucumber (Cucumis sativus), an original host of C. orbiculare, we show that SRN1 and SRN2 potentiate host pattern-triggered immunity responses. Consistent with this, C. orbiculare SRN1 and SRN2 deletion mutants exhibited increased virulence on the host. In vitro analysis revealed that SRN1 specifically cleaves single-stranded RNAs at guanosine, leaving a 3'-end phosphate. Importantly, the potentiation of C. sativus responses by SRN1 and SRN2, present in the apoplast, depends on ribonuclease catalytic residues. We propose that the pathogen-derived apoplastic guanosine-specific single-stranded endoribonucleases lead to immunity potentiation in plants.


Assuntos
Cucumis sativus , Ribonucleases , Cucumis sativus/microbiologia , Fungos , Plantas , Imunidade , Doenças das Plantas/microbiologia , Imunidade Vegetal
11.
Int J Mol Sci ; 25(16)2024 Aug 08.
Artigo em Inglês | MEDLINE | ID: mdl-39201361

RESUMO

Plant recognition of pathogen-associated molecular patterns (PAMPs) is pivotal in triggering immune responses, highlighting their potential as inducers of plant immunity. However, the number of PAMPs identified and applied in such contexts remains limited. In this study, we characterize a novel PAMP, designated Ss4368, which is derived from Scleromitrula shiraiana. Ss4368 is specifically distributed among a few fungal genera, including Botrytis, Monilinia, and Botryotinia. The transient expression of Ss4368 elicits cell death in a range of plant species. The signaling peptides, three conserved motifs, and cysteine residues (C46, C88, C112, C130, and C148) within Ss4368 are crucial for inducing robust cell death. Additionally, these signaling peptides are essential for the protein's localization to the apoplast. The cell death induced by Ss4368 and its homologous protein, Bc4368, is independent of the SUPPRESSOR OF BIR1-1 (SOBIR1), BRI1-ASSOCIATED KINASE-1 (BAK1), and salicylic acid (SA) pathways. Furthermore, the immune responses triggered by Ss4368 and Bc4368 significantly enhance the resistance of Nicotiana benthamiana to Phytophthora capsici. Therefore, we propose that Ss4368, as a novel PAMP, holds the potential for developing strategies to enhance plant resistance against P. capsici.


Assuntos
Morte Celular , Resistência à Doença , Nicotiana , Moléculas com Motivos Associados a Patógenos , Phytophthora , Doenças das Plantas , Imunidade Vegetal , Phytophthora/patogenicidade , Resistência à Doença/genética , Doenças das Plantas/microbiologia , Doenças das Plantas/genética , Moléculas com Motivos Associados a Patógenos/metabolismo , Nicotiana/microbiologia , Nicotiana/genética , Proteínas Fúngicas/metabolismo , Proteínas Fúngicas/genética , Proteínas de Plantas/metabolismo , Proteínas de Plantas/genética , Regulação da Expressão Gênica de Plantas , Células Vegetais/metabolismo , Células Vegetais/microbiologia
12.
Infect Immun ; 91(2): e0033222, 2023 02 16.
Artigo em Inglês | MEDLINE | ID: mdl-36794951

RESUMO

OmpU is one of the major porins of Vibrio cholerae, a Gram-negative human pathogen. Previously, we showed that OmpU stimulates host monocytes and macrophages and induces the production of proinflammatory mediators via activation of the Toll-like receptor 1/2 (TLR1/2)-MyD88-dependent pathways. In the present study, we show that OmpU activates murine dendritic cells (DCs) via activation of the TLR2-mediated pathway and the NLRP3 inflammasome, leading to the production of proinflammatory cytokines and DC maturation. Our data reveal that although TLR2 plays an important role in providing both priming and the activation signal for the NLRP3 inflammasome in OmpU-activated DCs, OmpU is capable of activating the NLRP3 inflammasome, even in the absence of TLR2, if a priming signal is given. Furthermore, we show that the OmpU-mediated interleukin-1ß (IL-1ß) production in DCs depends on calcium flux and mitochondrial reactive oxygen species (mitoROS) generation. Interestingly, both OmpU translocation to the mitochondria of DCs as well as calcium signaling contribute to mitoROS production and prompt NLRP3 inflammasome activation. We also demonstrate that OmpU induces downstream signaling via activation of phosphoinositide-3-kinase (PI3K)-AKT, protein kinase C (PKC), mitogen-activated protein kinases (MAPKs), and transcription factor NF-κB. Furthermore, our data reveal that OmpU-mediated activation of TLR2 induces signaling via PKC, MAPKs p38 and extracellular signal-regulated kinase (ERK), and transcription factor NF-κB; however, PI3K and MAPK Jun N-terminal protein kinase (JNK) are activated in TLR2 independent manner.


Assuntos
Inflamassomos , Vibrio cholerae , Humanos , Animais , Camundongos , Inflamassomos/metabolismo , Receptor 2 Toll-Like/metabolismo , NF-kappa B/metabolismo , Proteína 3 que Contém Domínio de Pirina da Família NLR/metabolismo , Vibrio cholerae/metabolismo , Porinas/metabolismo , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Receptor 1 Toll-Like/metabolismo , Células Dendríticas/metabolismo , Fosfatidilinositol 3-Quinases/metabolismo
13.
Neurobiol Dis ; 188: 106339, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37913832

RESUMO

Peripheral contact to pathogen-associated molecular patterns (PAMPs) evokes a systemic innate immune response which is rapidly relayed to the central nervous system (CNS). The remarkable cellular heterogeneity of the CNS poses a significant challenge to the study of cell type and stimulus dependent responses of neural cells during acute inflammation. Here we utilized single nuclei RNA sequencing (snRNAseq), serum proteome profiling and primary cell culture methods to systematically compare the acute response of the mammalian brain to the bacterial PAMP lipopolysaccharide (LPS) and the viral PAMP polyinosinic:polycytidylic acid (Poly(I:C)), at single cell resolution. Our study unveiled convergent transcriptional cytokine and cellular stress responses in brain vascular and ependymal cells and a downregulation of several key mediators of directed blood brain barrier (BBB) transport. In contrast the neuronal response to PAMPs was limited in acute neuroinflammation. Moreover, our study highlighted the dominant role of IFN signalling upon Poly(I:C) challenge, particularly in cells of the oligodendrocyte lineage. Collectively our study unveils heterogeneous, shared and distinct cell type and stimulus dependent acute responses of the CNS to bacterial and viral PAMP challenges. Our findings highlight inflammation induced dysregulations of BBB-transporter gene expression, suggesting potential translational implications on drug pharmacokinetics variability during acute neuroinflammation. The pronounced dependency of oligodendrocytes on IFN stimulation during viral PAMP challenges, emphasizes their limited molecular viral response repertoire.


Assuntos
Lipopolissacarídeos , Doenças Neuroinflamatórias , Animais , Lipopolissacarídeos/farmacologia , Moléculas com Motivos Associados a Patógenos , Sistema Nervoso Central , Inflamação , Mamíferos
14.
J Exp Bot ; 74(4): 1207-1220, 2023 02 13.
Artigo em Inglês | MEDLINE | ID: mdl-36377754

RESUMO

When attacked by herbivores, plants produce electrical signals which can activate the synthesis of the defense mediator jasmonate. These wound-induced membrane potential changes can occur in response to elicitors that are released from damaged plant cells. We list plant-derived elicitors of membrane depolarization. These compounds include the amino acid l-glutamate (Glu), a potential ligand for GLUTAMATE RECEPTOR-LIKE (GLR) proteins that play roles in herbivore-activated electrical signaling. How are membrane depolarization elicitors dispersed in wounded plants? In analogy with widespread turgor-driven cell and organ movements, we propose osmoelectric siphon mechanisms for elicitor transport. These mechanisms are based on membrane depolarization leading to cell water shedding into the apoplast followed by membrane repolarization and water uptake. We discuss two related mechanisms likely to occur in response to small wounds and large wounds that trigger leaf-to-leaf electrical signal propagation. To reduce jasmonate pathway activation, a feeding insect must cut through tissues cleanly. If their mandibles become worn, the herbivore is converted into a robust plant defense activator. Our models may therefore help to explain why numerous plants produce abrasives which can blunt herbivore mouthparts. Finally, if verified, the models we propose may be generalizable for cell to cell transport of water and pathogen-derived regulators.


Assuntos
Plantas , Água , Água/metabolismo , Plantas/metabolismo , Oxilipinas/metabolismo , Ciclopentanos/metabolismo , Herbivoria
15.
J Exp Bot ; 74(15): 4367-4376, 2023 08 17.
Artigo em Inglês | MEDLINE | ID: mdl-37226440

RESUMO

The constant battle of survival between pathogens and host plants has played a crucial role in shaping the course of their co-evolution. However, the major determinants of the outcome of this ongoing arms race are the effectors secreted by pathogens into host cells. These effectors perturb the defense responses of plants to promote successful infection. In recent years, extensive research in the area of effector biology has reported an increase in the repertoire of pathogenic effectors that mimic or target the conserved ubiquitin-proteasome pathway. The role of the ubiquitin-mediated degradation pathway is well known to be indispensable for various aspects of a plant's life, and thus targeting or mimicking it seems to be a smart strategy adopted by pathogens. Therefore, this review summarizes recent findings on how some pathogenic effectors mimic or act as one of the components of the ubiquitin-proteasome machinery while others directly target the plant's ubiquitin-proteasome system.


Assuntos
Plantas , Complexo de Endopeptidases do Proteassoma , Complexo de Endopeptidases do Proteassoma/metabolismo , Ubiquitinação , Plantas/metabolismo , Ubiquitina-Proteína Ligases/metabolismo , Ubiquitina/metabolismo , Doenças das Plantas , Imunidade Vegetal
16.
J Exp Bot ; 74(19): 6069-6088, 2023 10 13.
Artigo em Inglês | MEDLINE | ID: mdl-37429579

RESUMO

The plant immune system is constituted of two functionally interdependent branches that provide the plant with an effective defense against microbial pathogens. They can be considered separate since one detects extracellular pathogen-associated molecular patterns by means of receptors on the plant surface, while the other detects pathogen-secreted virulence effectors via intracellular receptors. Plant defense depending on both branches can be effectively suppressed by host-adapted microbial pathogens. In this review we focus on bacterially driven suppression of the latter, known as effector-triggered immunity (ETI) and dependent on diverse NOD-like receptors (NLRs). We examine how some effectors secreted by pathogenic bacteria carrying type III secretion systems can be subject to specific NLR-mediated detection, which can be evaded by the action of additional co-secreted effectors (suppressors), implying that virulence depends on the coordinated action of the whole repertoire of effectors of any given bacterium and their complex epistatic interactions within the plant. We consider how ETI activation can be avoided by using suppressors to directly alter compromised co-secreted effectors, modify plant defense-associated proteins, or occasionally both. We also comment on the potential assembly within the plant cell of multi-protein complexes comprising both bacterial effectors and defense protein targets.


Assuntos
Bactérias , Plantas , Plantas/metabolismo , Bactérias/metabolismo , Proteínas de Plantas/metabolismo , Proteínas NLR , Imunidade Vegetal , Doenças das Plantas/microbiologia , Proteínas de Bactérias/metabolismo
17.
Brain Behav Immun ; 111: 259-269, 2023 07.
Artigo em Inglês | MEDLINE | ID: mdl-37116592

RESUMO

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) produces an array of neurologic and neuropsychiatric symptoms in the acute and post-acute phase of infection (PASC; post-acute sequelae of SARS-CoV-2 infection). Neuroinflammatory processes are considered key factors in the etiology of these symptoms. Several mechanisms underpinning the development of inflammatory events in the brain have been proposed including SARS-CoV-2 neurotropism and peripheral inflammatory responses (i.e., cytokine storm) to infection, which might produce neuroinflammation via immune-to-brain signaling pathways. In this review, we explore evidence in support of an alternate mechanism whereby structural proteins (e.g., spike and spike S1 subunit) derived from SARS-CoV-2 virions function as pathogen-associated molecular patterns (PAMPs) to elicit proinflammatory immune responses in the periphery and/or brain via classical Toll-Like Receptor (TLR) inflammatory pathways. We propose that SARS-CoV-2 structural proteins might directly produce inflammatory processes in brain independent of and/or in addition to peripheral proinflammatory effects, which might converge to play a causal role in the development of neurologic/neuropsychiatric symptoms in COVID-19.


Assuntos
COVID-19 , Humanos , SARS-CoV-2 , Doenças Neuroinflamatórias , Síndrome de COVID-19 Pós-Aguda , Transdução de Sinais
18.
Parasite Immunol ; 45(2): e12951, 2023 02.
Artigo em Inglês | MEDLINE | ID: mdl-36114607

RESUMO

C-type lectin receptors (CLRs) constitute a category of innate immune receptors that play an essential role in the antifungal immune response. For over two decades, scientists have uncovered what are the fungal ligands recognized by CLRs and how these receptors initiate the immune response. Such studies have allowed the identification of genetic polymorphisms in genes encoding for CLRs or for proteins involved in the signalisation cascade they trigger. Nevertheless, our understanding of how these receptors functions and the full extent of their function during the antifungal immune response is still at its infancy. In this review, we summarize some of the main findings about CLRs in antifungal immunity and discuss what the future might hold for the field.


Assuntos
Antifúngicos , Micoses , Humanos , Micoses/genética , Micoses/metabolismo , Lectinas Tipo C/genética , Lectinas Tipo C/metabolismo , Imunidade Inata
19.
Inflamm Res ; 72(5): 915-928, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-36964784

RESUMO

OBJECTIVE AND DESIGN: BacSp222 bacteriocin is a bactericidal and proinflammatory peptide stimulating immune cells to produce selected cytokines and NO in NF-ĸB dependent manner. This study aims to identify the receptor which mediates this activity. METHODS: We applied fluorescently labeled BacSp222 and a confocal microscopy imaging to analyze the direct interaction of the bacteriocin with the cells. Reporter HEK-Blue cells overexpressing human toll-like receptors (TLR2, TLR4, TLR5 or TLR2/TLR1 and TLR2/TLR6 heterodimers) were stimulated with BacSp222, and then the activity of NF-ĸB-dependent secreted embryonic alkaline phosphatase (SEAP) was measured. In turn, formylated peptide receptor (FPR) or TLR2 antagonists were used to verify bacteriocin-stimulated TNF production by murine monocyte-macrophage cell lines. RESULTS: BacSp222 undergoes internalization into cells without disturbing the cell membrane. FPR antagonists do not affect TNF produced by BacSp222-stimulated murine macrophage-like cells. In contrast, BacSp222 stimulates NF-ĸB activation in HEK-Blue overexpressing TLR2 or TLR2/TLR6 heterodimer, but not TLR2/TLR1, TLR4 or TLR5 receptors. Moreover, TLR2-specific antagonists inhibit NF-ĸB signaling in BacSp222-stimulated HEK-Blue TLR2/TLR6 cells and reduce TNF release by BacSp222-treated RAW 264.7 and P388.D1. CONCLUSIONS: BacSp222 is a novel ligand for TLR2/TLR6 heterodimer. By binding TLR complex the bacteriocin undergoes internalization, inducing proinflammatory signaling that employs MyD88 and NF-ĸB pathways.


Assuntos
Bacteriocinas , Receptor 6 Toll-Like , Humanos , Animais , Camundongos , Ligantes , Receptor 6 Toll-Like/metabolismo , NF-kappa B/metabolismo , Receptor 1 Toll-Like , Receptor 2 Toll-Like/metabolismo , Receptor 5 Toll-Like , Receptor 4 Toll-Like , Bacteriocinas/farmacologia
20.
Anim Biotechnol ; 34(8): 3729-3738, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37226739

RESUMO

Pathogen-associated molecular patterns (PAMPs) such as lipopolysaccharide (LPS), peptidoglycan (PGN), Polyinosinic-polycytidylic acid (poly I:C), and CpG Oligodeoxynucleotides (ODN) are recognized by Toll-like receptors (TLR). This study aimed to investigate the effect of diverse PAMPs on the transcription of TLR signaling pathway genes in goat blood. Whole blood was collected from 3 female BoerXSpanish goats and treated with the following PAMPs: 10 µg/ml LPS, PGN, CpG ODN (2216), CpG ODN (2006), and 12.5 µg/ml Poly I:C. Blood-treated PBS served as a control. The expression of 84 genes in the human TLR signaling pathway RT2 PCR Array (Qiagen) was evaluated using real-time PCR. Treatment with PBS affected the expression of 74 genes, Poly I:C affected the expression of 40 genes, t ODN 2006 affected the expression of 50 genes, ODN 2216 affected the expression of 52 genes, LPS affected the expression of 49 genes, while PGN affected the expression of 49 genes. Our results show that PAMPs modulated and increased the expression of genes in the TLR signaling pathway. These results highlight important insights into how the host responds to different pathogens and may help design adjuvants for therapeutics and vaccines that target different.


Assuntos
Lipopolissacarídeos , Moléculas com Motivos Associados a Patógenos , Feminino , Animais , Humanos , Lipopolissacarídeos/farmacologia , Cabras/genética , Cabras/metabolismo , Receptores Toll-Like/genética , Receptores Toll-Like/metabolismo , Transdução de Sinais/genética , Poli I
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