Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 366
Filtrar
1.
Cell Death Dis ; 13(12): 1029, 2022 12 08.
Artigo em Inglês | MEDLINE | ID: mdl-36481780

RESUMO

The NAIP/NLRC4 inflammasome is classically associated with the detection of bacterial invasion to the cytosol. However, recent studies have demonstrated that NAIP/NLRC4 is also activated in non-bacterial infections, and in sterile inflammation. Moreover, in addition to the well-established model for the detection of bacterial proteins by NAIP proteins, the participation of other cytosolic pathways in the regulation of NAIP/NLRC4-mediated responses has been reported in distinct contexts. Using pharmacological inhibition and genetic deletion, we demonstrate here that cathepsins, well known for their involvement in NLRP3 activation, also regulate NAIP/NLRC4 responses to cytosolic flagellin in murine and human macrophages. In contrast to that observed for NLRP3 agonists, cathepsins inhibition did not reduce ASC speck formation or caspase-1 maturation in response to flagellin, ruling out their participation in the effector phase of NAIP/NLRC4 activation. Moreover, cathepsins had no impact on NF-κB-mediated priming of pro-IL-1ß, thus suggesting these proteases act downstream of the NAIP/NLRC4 inflammasome activation. IL-1ß levels secreted in response to flagellin were reduced in the absence of either cathepsins or Gasdermin-D (GSDMD), a molecule involved in the induction of pyroptosis and cytokines release. Notably, IL-1ß secretion was abrogated in the absence of both GSDMD and cathepsins, demonstrating their non-redundant roles for the optimal IL-1ß release in response to cytosolic flagellin. Given the central role of NAIP/NLRC4 inflammasomes in controlling infection and, also, induction of inflammatory pathologies, many efforts have been made to uncover novel molecules involved in their regulation. Thus, our findings bring together a relevant contribution by describing the role of cathepsins as players in the NAIP/NLRC4-mediated responses.


Assuntos
Proteínas Adaptadoras de Sinalização CARD , Proteínas de Ligação ao Cálcio , Catepsinas , Lisossomos , Proteína Inibidora de Apoptose Neuronal , Animais , Humanos , Camundongos , Proteínas de Ligação ao Cálcio/metabolismo , Proteínas Adaptadoras de Sinalização CARD/metabolismo , Catepsinas/metabolismo , Deleção de Genes , Proteína Inibidora de Apoptose Neuronal/metabolismo , Interleucina-1beta/metabolismo
2.
Front Immunol ; 13: 953530, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36189327

RESUMO

Innate immunity is a primary defense system against microbial infections. Innate immune pattern recognition receptors (PRRs) play pivotal roles in detection of invading pathogens. When pathogens, such as bacteria and viruses, invade our bodies, their components are recognized by PRRs as pathogen-associated molecular patterns (PAMPs), activating the innate immune system. Cellular components such as DNA and RNA, acting as damage-associated molecular patterns (DAMPs), also activate innate immunity through PRRs under certain conditions. Activation of PRRs triggers inflammatory responses, interferon-mediated antiviral responses, and the activation of acquired immunity. Research on innate immune receptors is progressing rapidly. A variety of these receptors has been identified, and their regulatory mechanisms have been elucidated. Nucleotide-binding and oligomerization domain (NOD)-like receptors (NLRs) constitute a major family of intracellular PRRs and are involved in not only combating pathogen invasion but also maintaining normal homeostasis. Some NLRs are known to form multi-protein complexes called inflammasomes, a process that ultimately leads to the production of inflammatory cytokines and induces pyroptosis through the proteolytic cascade. The aberrant activation of NLRs has been found to be associated with autoimmune diseases. Therefore, NLRs are considered targets for drug discovery, such as for antiviral drugs, immunostimulants, antiallergic drugs, and autoimmune disease drugs. This review summarizes our recent understanding of the activation and regulation mechanisms of NLRs, with a particular focus on their structural biology. These include NOD2, neuronal apoptosis inhibitory protein (NAIP)/NLRC4, NLR family pyrin domain containing 1 (NLRP1), NLRP3, NLRP6, and NLRP9. NLRs are involved in a variety of diseases, and their detailed activation mechanisms based on structural biology can aid in developing therapeutic agents in the future.


Assuntos
Antialérgicos , Inflamassomos , Adjuvantes Imunológicos , Antivirais , Biologia , Proteínas de Transporte/metabolismo , Citocinas/metabolismo , Inflamassomos/metabolismo , Interferons/metabolismo , Proteína 3 que Contém Domínio de Pirina da Família NLR/metabolismo , Proteína Inibidora de Apoptose Neuronal/metabolismo , Nucleotídeos/metabolismo , Padrões Moleculares Associados a Patógenos , RNA , Receptores de Reconhecimento de Padrão/metabolismo , Transdução de Sinais , Receptores Toll-Like/metabolismo
3.
Infect Immun ; 90(7): e0066321, 2022 07 21.
Artigo em Inglês | MEDLINE | ID: mdl-35678562

RESUMO

Salmonella enterica serovar Typhimurium is a Gram-negative pathogen that causes diseases ranging from gastroenteritis to systemic infection and sepsis. Salmonella uses type III secretion systems (T3SS) to inject effectors into host cells. While these effectors are necessary for bacterial invasion and intracellular survival, intracellular delivery of T3SS products also enables detection of translocated Salmonella ligands by cytosolic immune sensors. Some of these sensors form multimeric complexes called inflammasomes, which activate caspases that lead to interleukin-1 (IL-1) family cytokine release and pyroptosis. In particular, the Salmonella T3SS needle, inner rod, and flagellin proteins activate the NAIP/NLRC4 inflammasome in murine intestinal epithelial cells (IECs), which leads to restriction of bacterial replication and extrusion of infected IECs into the intestinal lumen, thereby preventing systemic dissemination of Salmonella. While these processes are quite well studied in mice, the role of the NAIP/NLRC4 inflammasome in human IECs remains unknown. Unexpectedly, we found the NAIP/NLRC4 inflammasome is dispensable for early inflammasome responses to Salmonella in both human IEC lines and enteroids. Additionally, NLRP3 and the adaptor protein ASC are not required for inflammasome activation in Caco-2 cells. Instead, we observed a necessity for caspase-4 and gasdermin D pore-forming activity in mediating inflammasome responses to Salmonella in Caco-2 cells. These findings suggest that unlike murine IECs, human IECs do not rely on NAIP/NLRC4 or NLRP3/ASC inflammasomes and instead primarily use caspase-4 to mediate inflammasome responses to Salmonella pathogenicity island 1 (SPI-1)-expressing Salmonella.


Assuntos
Inflamassomos , Animais , Proteínas Reguladoras de Apoptose , Proteínas Adaptadoras de Sinalização CARD , Células CACO-2 , Proteínas de Ligação ao Cálcio , Caspases Iniciadoras , Células Epiteliais/metabolismo , Humanos , Inflamassomos/metabolismo , Camundongos , Proteína 3 que Contém Domínio de Pirina da Família NLR/metabolismo , Proteína Inibidora de Apoptose Neuronal , Salmonella typhimurium , Sorogrupo
4.
Immunohorizons ; 6(3): 243-252, 2022 03 17.
Artigo em Inglês | MEDLINE | ID: mdl-35301258

RESUMO

Hosts rely on the innate immune system to clear pathogens in response to infection. Pathogen-associated molecular patterns bind to innate immune receptors and engage activation of downstream signaling to initiate a host immune response to fight infection. A key component of this innate response is programmed cell death. Recent work has highlighted significant cross-talk and functional redundancy between cell death pathways, leading to the discovery of PANoptosis, an inflammatory programmed cell death pathway dependent on PANoptosomes, which are innate immune danger-sensing complexes that activate inflammatory cell death and contain caspases with or without inflammasome components and receptor interacting protein homotypic interaction motif-containing proteins. Although PANoptosis has been characterized in response to a growing number of pathogens, inflammatory diseases, and cancer, its role and the functional consequences of PANoptotic component modulation during NLR family CARD domain-containing protein 4 (NLRC4) activation by Pseudomonas aeruginosa infection remain unknown. In this study, we show that P. aeruginosa can induce PANoptosis in mouse bone marrow-derived macrophages (BMDMs). Only the combined deletion of caspase-1, -11, -8, and RIPK3 protected mouse BMDMs from cell death. Moreover, we showed that PANoptotic components act in a compensatory manner; in the absence of NAIP5 and NLRC4 during P. aeruginosa challenge, activation of caspase-1, -3, -7, and -8 was reduced, whereas alternative cell death molecules such as RIPK1 and MLKL were activated in mouse BMDMs. Taken together, these data highlight the extensive cross-talk between cell death signaling molecules and showcase the plasticity of the system.


Assuntos
Macrófagos , Necroptose , Animais , Caspases/metabolismo , Inflamassomos/metabolismo , Camundongos , Proteína Inibidora de Apoptose Neuronal/metabolismo , Fosforilação , Proteínas Quinases/genética , Proteínas Quinases/metabolismo
5.
PLoS Pathog ; 18(1): e1009718, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-35073381

RESUMO

Salmonella enterica serovar Typhimurium is a Gram-negative pathogen that uses two distinct type III secretion systems (T3SSs), termed Salmonella pathogenicity island (SPI)-1 and SPI-2, to deliver virulence factors into the host cell. The SPI-1 T3SS enables Salmonella to invade host cells, while the SPI-2 T3SS facilitates Salmonella's intracellular survival. In mice, a family of cytosolic immune sensors, including NAIP1, NAIP2, and NAIP5/6, recognizes the SPI-1 T3SS needle, inner rod, and flagellin proteins, respectively. Ligand recognition triggers assembly of the NAIP/NLRC4 inflammasome, which mediates caspase-1 activation, IL-1 family cytokine secretion, and pyroptosis of infected cells. In contrast to mice, humans encode a single NAIP that broadly recognizes all three ligands. The role of NAIP/NLRC4 or other inflammasomes during Salmonella infection of human macrophages is unclear. We find that although the NAIP/NLRC4 inflammasome is essential for detecting T3SS ligands in human macrophages, it is partially required for responses to infection, as Salmonella also activated the NLRP3 and CASP4/5 inflammasomes. Importantly, we demonstrate that combinatorial NAIP/NLRC4 and NLRP3 inflammasome activation restricts Salmonella replication in human macrophages. In contrast to SPI-1, the SPI-2 T3SS inner rod is not sensed by human or murine NAIPs, which is thought to allow Salmonella to evade host recognition and replicate intracellularly. Intriguingly, we find that human NAIP detects the SPI-2 T3SS needle protein. Critically, in the absence of both flagellin and the SPI-1 T3SS, the NAIP/NLRC4 inflammasome still controlled intracellular Salmonella burden. These findings reveal that recognition of Salmonella SPI-1 and SPI-2 T3SSs and engagement of both the NAIP/NLRC4 and NLRP3 inflammasomes control Salmonella infection in human macrophages.


Assuntos
Inflamassomos/imunologia , Macrófagos/imunologia , Macrófagos/microbiologia , Infecções por Salmonella/imunologia , Sistemas de Secreção Tipo III/imunologia , Proteínas Adaptadoras de Sinalização CARD/imunologia , Proteínas de Ligação ao Cálcio/imunologia , Humanos , Proteína 3 que Contém Domínio de Pirina da Família NLR/imunologia , Proteína Inibidora de Apoptose Neuronal/imunologia , Salmonella typhimurium/imunologia , Salmonella typhimurium/patogenicidade , Virulência
6.
Biochem Soc Trans ; 49(6): 2601-2610, 2021 12 17.
Artigo em Inglês | MEDLINE | ID: mdl-34854889

RESUMO

The gut relies on the complex interaction between epithelial, stromal and immune cells to maintain gut health in the face of food particles and pathogens. Innate sensing by the intestinal epithelium is critical for maintaining epithelial barrier function and also orchestrating mucosal immune responses. Numerous innate pattern recognition receptors (PRRs) are involved in such sensing. In recent years, several Nucleotide-binding-domain and Leucine-rich repeat-containing receptors (NLRs) have been found to partake in pathogen or damage sensing while also being implicated in gut pathologies, such as colitis and colorectal cancer (CRC). Here, we discuss the current literature focusing on NLR family apoptosis inhibitory proteins (NAIPs) and other NLRs that have non-inflammasome roles in the gut. The mechanisms behind NLR-mediated protection often converges on similar signalling pathways, such as STAT3, MAPK and NFκB. Further understanding of how these NLRs contribute to the maintenance of gut homeostasis will be important for understanding gut pathologies and developing new therapies.


Assuntos
Inflamassomos/metabolismo , Mucosa Intestinal/metabolismo , Proteínas NLR/metabolismo , Proteína Inibidora de Apoptose Neuronal/metabolismo , Animais , Neoplasias Colorretais/metabolismo , Humanos
7.
Sci Immunol ; 6(66): eabm1201, 2021 Dec 03.
Artigo em Inglês | MEDLINE | ID: mdl-34860580

RESUMO

DDX17 binds short interspersed nuclear element RNAs to nucleate a dual NLRC4/NLRP3 inflammasome, highlighting the emerging role of endogenous ligands in NLRC4 activation (see the related Research Article by Wang et al.).


Assuntos
Inflamassomos , Proteína Inibidora de Apoptose Neuronal , Proteínas Adaptadoras de Sinalização CARD , Proteínas de Ligação ao Cálcio , Imunidade Inata , Inflamassomos/metabolismo , Proteína Inibidora de Apoptose Neuronal/metabolismo
8.
Medicine (Baltimore) ; 100(46): e27882, 2021 Nov 19.
Artigo em Inglês | MEDLINE | ID: mdl-34797333

RESUMO

ABSTRACT: The inhibitor of apoptosis family proteins (IAPs) plays a crucial role in the process of carcinogenesis by regulating apoptosis and maintaining the tissue balance.In this study, a transcriptomic analysis of IAP-encoding genes in colon cancer was performed using oligonucleotide microarrays.Adenocarcinoma and healthy colon tissue samples were collected from 32 patients (16 females and 16 males) who underwent surgery due to colon cancer. The mRNA was extracted from tissue samples and tested using oligonucleotide microarrays (Affymetrix). The results were validated using the qRT-PCR technique. Hierarchical grouping was used to allocate 37 samples of normalized mRNA concentrations into 4 groups, with statistically significant differences in gene expression between these groups. The group of genes associated with colon cancer, including IAP-encoding gene - BIRC5 (Survivin), was selected for further testing.Our study confirmed an increased expression of BIRC5 in colon cancer tissue when compared to the control group. Increased levels of Neuronal Apoptosis Inhibitory Proteins were detected only in low-stage colon cancer, while the expression of Human X Chromosome-Encoded inhibitor of apoptosis family proteins decreased in colon cancer.The transcriptional activity of IAP-encoding genes varied, depending on the severity of colon cancer. The concentration of mRNA, encoding BIRC5 was elevated in samples obtained from more advanced colon cancer. Hence BIRC5 could be used as a complementary parameter for the diagnosis and prognosis of colon cancer.


Assuntos
Apoptose/genética , Neoplasias do Colo/genética , Neoplasias do Colo/metabolismo , Proteínas Inibidoras de Apoptose/genética , Survivina/genética , Biomarcadores Tumorais , Neoplasias do Colo/patologia , Feminino , Regulação Neoplásica da Expressão Gênica , Humanos , Masculino , Proteína Inibidora de Apoptose Neuronal , Prognóstico , RNA Mensageiro/genética , RNA Mensageiro/metabolismo
9.
Proc Natl Acad Sci U S A ; 118(16)2021 04 20.
Artigo em Inglês | MEDLINE | ID: mdl-33846244

RESUMO

The gut epithelium serves to maximize the surface for nutrient and fluid uptake, but at the same time must provide a tight barrier to pathogens and remove damaged intestinal epithelial cells (IECs) without jeopardizing barrier integrity. How the epithelium coordinates these tasks remains a question of significant interest. We used imaging and an optical flow analysis pipeline to study the dynamicity of untransformed murine and human intestinal epithelia, cultured atop flexible hydrogel supports. Infection with the pathogen Salmonella Typhimurium (STm) within minutes elicited focal contractions with inward movements of up to ∼1,000 IECs. Genetics approaches and chimeric epithelial monolayers revealed contractions to be triggered by the NAIP/NLRC4 inflammasome, which sensed type-III secretion system and flagellar ligands upon bacterial invasion, converting the local tissue into a contraction epicenter. Execution of the response required swift sublytic Gasdermin D pore formation, ion fluxes, and the propagation of a myosin contraction pulse across the tissue. Importantly, focal contractions preceded, and could be uncoupled from, the death and expulsion of infected IECs. In both two-dimensional monolayers and three-dimensional enteroids, multiple infection-elicited contractions coalesced to produce shrinkage of the epithelium as a whole. Monolayers deficient for Caspase-1(-11) or Gasdermin D failed to elicit focal contractions but were still capable of infected IEC death and expulsion. Strikingly, these monolayers lost their integrity to a markedly higher extent than wild-type counterparts. We propose that prompt NAIP/NLRC4/Caspase-1/Gasdermin D/myosin-dependent contractions allow the epithelium to densify its cell packing in infected regions, thereby preventing tissue disintegration due to the subsequent IEC death and expulsion process.


Assuntos
Mucosa Intestinal/metabolismo , Mucosa Intestinal/fisiologia , Proteína Inibidora de Apoptose Neuronal/metabolismo , Animais , Infecções Bacterianas/fisiopatologia , Proteínas Adaptadoras de Sinalização CARD/metabolismo , Proteínas de Ligação ao Cálcio/metabolismo , Caspase 1/metabolismo , Caspases/metabolismo , Células Epiteliais/metabolismo , Epitélio/metabolismo , Humanos , Inflamassomos , Mucosa Intestinal/microbiologia , Intestinos , Camundongos , Contração Muscular/fisiologia , Cultura Primária de Células , Receptores de Reconhecimento de Padrão/metabolismo , Salmonella typhimurium/patogenicidade , Sistemas de Secreção Tipo III/metabolismo
10.
PLoS Pathog ; 17(4): e1009417, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33861800

RESUMO

Macrophages are important drivers of pathogenesis and progression to AIDS in HIV infection. The virus in the later phases of the infection is often predominantly macrophage-tropic and this tropism contributes to a chronic inflammatory and immune activation state that is observed in HIV patients. Pattern recognition receptors of the innate immune system are the key molecules that recognise HIV and mount the inflammatory responses in macrophages. The innate immune response against HIV-1 is potent and elicits caspase-1-dependent pro-inflammatory cytokine production of IL-1ß and IL-18. Although, NLRP3 has been reported as an inflammasome sensor dictating this response little is known about the pattern recognition receptors that trigger the "priming" signal for inflammasome activation, the NLRs involved or the HIV components that trigger the response. Using a combination of siRNA knockdowns in monocyte derived macrophages (MDMs) of different TLRs and NLRs as well as chemical inhibition, it was demonstrated that HIV Vpu could trigger inflammasome activation via TLR4/NLRP3 leading to IL-1ß/IL-18 secretion. The priming signal is triggered via TLR4, whereas the activation signal is triggered by direct effects on Kv1.3 channels, causing K+ efflux. In contrast, HIV gp41 could trigger IL-18 production via NAIP/NLRC4, independently of priming, as a one-step inflammasome activation. NAIP binds directly to the cytoplasmic tail of HIV envelope protein gp41 and represents the first non-bacterial ligand for the NAIP/NLRC4 inflammasome. These divergent pathways represent novel targets to resolve specific inflammatory pathologies associated with HIV-1 infection in macrophages.


Assuntos
Infecções por HIV/virologia , Inflamassomos/imunologia , Interleucina-18/metabolismo , Interleucina-1beta/metabolismo , Macrófagos/virologia , Fragmentos de Peptídeos/metabolismo , Comunicação Celular/genética , Comunicação Celular/imunologia , Expressão Gênica/genética , Expressão Gênica/imunologia , Infecções por HIV/metabolismo , Humanos , Imunidade Inata/genética , Imunidade Inata/imunologia , Inflamassomos/metabolismo , Macrófagos/imunologia , Proteína Inibidora de Apoptose Neuronal/genética , Transdução de Sinais/imunologia
11.
Mucosal Immunol ; 14(3): 615-629, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33731826

RESUMO

The gut epithelium is a critical protective barrier. Its NAIP/NLRC4 inflammasome senses infection by Gram-negative bacteria, including Salmonella Typhimurium (S.Tm) and promotes expulsion of infected enterocytes. During the first ~12-24 h, this reduces mucosal S.Tm loads at the price of moderate enteropathy. It remained unknown how this NAIP/NLRC4-dependent tradeoff would develop during subsequent infection stages. In NAIP/NLRC4-deficient mice, S.Tm elicited severe enteropathy within 72 h, characterized by elevated mucosal TNF (>20 pg/mg) production from bone marrow-derived cells, reduced regeneration, excessive enterocyte loss, and a collapse of the epithelial barrier. TNF-depleting antibodies prevented this destructive pathology. In hosts proficient for epithelial NAIP/NLRC4, a heterogeneous enterocyte death response with both apoptotic and pyroptotic features kept S.Tm loads persistently in check, thereby preventing this dire outcome altogether. Our results demonstrate that immediate and selective removal of infected enterocytes, by locally acting epithelium-autonomous NAIP/NLRC4, is required to avoid a TNF-driven inflammatory hyper-reaction that otherwise destroys the epithelial barrier.


Assuntos
Proteínas Reguladoras de Apoptose/metabolismo , Proteínas de Ligação ao Cálcio/metabolismo , Enterócitos/imunologia , Inflamação/imunologia , Mucosa Intestinal/patologia , Proteína Inibidora de Apoptose Neuronal/metabolismo , Infecções por Salmonella/imunologia , Salmonella typhimurium/fisiologia , Animais , Proteínas Reguladoras de Apoptose/genética , Proteínas de Ligação ao Cálcio/genética , Células Cultivadas , Citotoxicidade Imunológica , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Proteína Inibidora de Apoptose Neuronal/genética , Junções Íntimas/metabolismo , Fator de Necrose Tumoral alfa/metabolismo
12.
Cell Death Dis ; 12(2): 158, 2021 02 05.
Artigo em Inglês | MEDLINE | ID: mdl-33547278

RESUMO

Uric acid (UA), a product of purine nucleotide degradation able to initiate an immune response, represents a breakpoint in the evolutionary history of humans, when uricase, the enzyme required for UA cleavage, was lost. Despite being inert in human cells, UA in its soluble form (sUA) can increase the level of interleukin-1ß (IL-1ß) in murine macrophages. We, therefore, hypothesized that the recognition of sUA is achieved by the Naip1-Nlrp3 inflammasome platform. Through structural modelling predictions and transcriptome and functional analyses, we found that murine Naip1 expression in human macrophages induces IL-1ß expression, fatty acid production and an inflammation-related response upon sUA stimulation, a process reversed by the pharmacological and genetic inhibition of Nlrp3. Moreover, molecular interaction experiments showed that Naip1 directly recognizes sUA. Accordingly, Naip may be the sUA receptor lost through the human evolutionary process, and a better understanding of its recognition may lead to novel anti-hyperuricaemia therapies.


Assuntos
Inflamassomos/metabolismo , Macrófagos/efeitos dos fármacos , Proteína 3 que Contém Domínio de Pirina da Família NLR/metabolismo , Proteína Inibidora de Apoptose Neuronal/metabolismo , Ácido Úrico/farmacologia , Animais , Ácidos Graxos/metabolismo , Humanos , Inflamassomos/genética , Inflamassomos/imunologia , Interleucina-1beta/metabolismo , Macaca mulatta , Macrófagos/imunologia , Macrófagos/metabolismo , Camundongos Endogâmicos C57BL , Proteína 3 que Contém Domínio de Pirina da Família NLR/genética , Proteína Inibidora de Apoptose Neuronal/genética , Ligação Proteica , Células THP-1 , Ácido Úrico/metabolismo
13.
J Cell Biol ; 220(3)2021 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-33535228

RESUMO

NLRC4 inflammasome activation and the subsequent maturation of IL-1ß and IL-18 are critical for protection against infection by bacterial pathogens. The epigenetic regulator Brd4 has emerged as a key player in inflammation by regulating the expression of inflammatory cytokines. However, whether Brd4 has any role in inflammasome activation remains undetermined. Here, we demonstrated that Brd4 is an important regulator of NLRC4 inflammasome activation in response to Salmonella typhimurium infection. Brd4-deficient bone marrow-derived macrophages (BMDMs) displayed impaired caspase-1 activation, ASC oligomerization, IL-1ß maturation, gasdermin-D cleavage, and pyroptosis in response to S.typhimurium infection. RNA sequencing and RT-PCR results revealed that the transcription of Naips was decreased in Brd4-deficient BMDMs. Brd4 formed a complex with IRF8/PU.1 and bound to the IRF8 and PU.1 binding motifs on the promoters of Naips to maintain the expression of Naips. Furthermore, myeloid lineage-specific Brd4 conditional knockout mice were more susceptible to S.typhimurium infection with increased mortality, bacterial loads, and tissue damage; impaired inflammasome-dependent cytokine production; and pyroptosis. Our studies identify a novel function of Brd4 in innate immunity by controlling inflammasome-mediated cytokine release and pyroptosis to effectively battle S.typhimurium infection.


Assuntos
Proteínas Reguladoras de Apoptose/metabolismo , Proteínas de Ligação ao Cálcio/metabolismo , Inflamassomos/metabolismo , Fatores Reguladores de Interferon/metabolismo , Proteínas Nucleares/metabolismo , Fatores de Transcrição/metabolismo , Transcrição Genética , Animais , Sequência de Bases , Proteínas Adaptadoras de Sinalização CARD/metabolismo , Ilhas de CpG/genética , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Macrófagos/metabolismo , Camundongos Knockout , Modelos Biológicos , Proteína Inibidora de Apoptose Neuronal/genética , Proteína Inibidora de Apoptose Neuronal/metabolismo , Proteínas Nucleares/deficiência , Proteínas de Ligação a Fosfato/metabolismo , Ligação Proteica , Proteínas Proto-Oncogênicas/metabolismo , Piroptose , Salmonella typhimurium/fisiologia , Transativadores/metabolismo , Fatores de Transcrição/deficiência
14.
Crit Rev Eukaryot Gene Expr ; 31(4): 35-48, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34587434

RESUMO

The inhibitors of apoptosis protein (IAP)/baculoviral IAP repeat containing (BIRC) gene families are necessary for cell protection, and most of these genes act as endogenous inhibitors of apoptosis. In some cancers, the over-expression of the BIRC gene is associated with cancer progression, multidrug resistance, poor prognosis and short-term survival. In this study, we aimed to assess the effect of the BIRC family in pan-cancer. We downloaded transcriptome and clinical data from 33 types of TCGA tumor samples and adjacent tissues. Then, the expression characteristics of IAP family members BIRC2, BIRC3, BIRC5, BIRC6 and BIRC7 in pan-cancer were analyzed. R packet and Cox regression were used to analyze the clinical correlation. In addition, the transcription level of BIRC and immune subtypes, stem cells, immune tumor microenvironment (TME) and drug sensitivity were analyzed by multidimensional correlation. Our studies have shown that the expression of IAP family members BIRC2, BIRC3, BIRC5, BIRC6, and BIRC7 is different in different tumor types, and the heterogeneity is obvious in cancers. Overall, our analysis showed that BIRC2, BIRC3, BIRC6, and BIRC7 were mainly down-regulated in tumors, whereas BIRC5 was mainly up-regulated in tumors. The expression of IAP family members is related to the overall survival of patients. However, the direction of the association varies depending on specific IAP subtypes and specific types of cancer. More specifically, BIRC5 is mainly related to poor prognosis. The rest of the IAP family showed either a survival advantage or a survival disadvantage, depending on the type of cancer. In addition, BIRC2, BIRC3, BIRC5, BIRC6 and BIRC7 were significantly correlated with immune infiltration subtypes and had different degrees of correlation with the degree of interstitial cell infiltration and tumor cell dryness. Finally, our study revealed that BIRC2, BIRC5, and BIRC7 genes may be related to drug resistance of tumor cells. Our systematic analysis of (IAP) gene expression and its relationship with immune infiltration, TME, cancer stem cells, drug sensitivity and prognosis of cancer patients highlights the need to study IAP family members as separate entities in each specific cancer type. In addition, our study confirmed that IAP family genes are promising therapeutic targets for cancer and potential prognostic indicators for clinical application, although further laboratory verification is needed.


Assuntos
Regulação Neoplásica da Expressão Gênica , Neoplasias/genética , Neoplasias/metabolismo , Proteína Inibidora de Apoptose Neuronal/genética , Proteína Inibidora de Apoptose Neuronal/metabolismo , Transcriptoma , Microambiente Tumoral , Apoptose , Resistencia a Medicamentos Antineoplásicos , Humanos , Proteínas Inibidoras de Apoptose , Prognóstico
15.
J Mol Histol ; 52(1): 113-123, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33237375

RESUMO

The neuronal apoptosis inhibitory protein (NAIP) is a constituent of the NLRC4 inflammasome, which plays a key role in innate immunity, and an antiapoptotic protein. Recently, we reported the previously undescribed role of NAIP in cell division. The liver is one of the body's most actively regenerative organs. Given the novel mitotic role of NAIP, we examined its expression in hepatic mass restoration. The major liver lobe of Wistar rats was removed, and samples from both newly formed liver tissue, assessed by positive Ki67 immunostaining, and the remnant, intact liver lobes from hepatectomized rats were taken 3 and 7 days after surgery. Naip5 and Naip6 mRNA levels were significantly higher in regenerating hepatic tissue than in intact liver lobe tissue, and this increase was also observed at the protein level. Naip5 and Naip6 mRNA in situ hybridization showed that this increase occurred in the hepatic parenchyma. The histology of the regenerated liver tissue was normal, with the exception of a noticeable deficiency of hepatic lobule central veins. The results of this study suggest the involvement of NAIP in liver mass restoration following partial hepatectomy.


Assuntos
Fígado/anatomia & histologia , Fígado/metabolismo , Proteína Inibidora de Apoptose Neuronal/metabolismo , Animais , Divisão Celular , Linhagem Celular , Regulação da Expressão Gênica , Hepatócitos/citologia , Hepatócitos/metabolismo , Humanos , Regeneração Hepática/genética , Masculino , Modelos Animais , Proteína Inibidora de Apoptose Neuronal/genética , Tamanho do Órgão , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Ratos Wistar
16.
J Immunol ; 206(3): 631-640, 2021 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-33380493

RESUMO

Infection of human macrophages with Salmonella enterica serovar Typhimurium (S. Typhimurium) leads to inflammasome activation. Inflammasomes are multiprotein complexes facilitating caspase-1 activation and subsequent gasdermin D-mediated cell death and IL-1ß and IL-18 cytokine release. The NAIP/NLRC4 inflammasome is activated by multiple bacterial protein ligands, including flagellin from the flagellum and the needle protein PrgI from the S. Typhimurium type III secretion system. In this study, we show that transfected ultrapure flagellin from S Typhimurium induced cell death and cytokine secretion in THP-1 cells and primary human monocyte-derived macrophages. In THP-1 cells, NAIP/NLRC4 and NLRP3 played redundant roles in inflammasome activation during infection with S. Typhimurium. Knockout of NAIP or NLRC4 in THP-1 cells revealed that flagellin, but not PrgI, now activated the NLRP3 inflammasome through a reactive oxygen species- and/or cathepsin-dependent mechanism that was independent of caspase-4/5 activity. In conclusion, our data suggest that NLRP3 can be activated by flagellin to act as a "safety net" to maintain inflammasome activation under conditions of suboptimal NAIP/NLRC4 activation, as observed in THP-1 cells, possibly explaining the redundant role of NLRP3 and NAIP/NLRC4 during S. Typhimurium infection.


Assuntos
Proteínas Adaptadoras de Sinalização CARD/metabolismo , Proteínas de Ligação ao Cálcio/metabolismo , Inflamassomos/metabolismo , Macrófagos/imunologia , Proteína 3 que Contém Domínio de Pirina da Família NLR/metabolismo , Proteína Inibidora de Apoptose Neuronal/metabolismo , Salmonella typhi/fisiologia , Febre Tifoide/imunologia , Apoptose , Proteínas Adaptadoras de Sinalização CARD/genética , Proteínas de Ligação ao Cálcio/genética , Caspases Iniciadoras/metabolismo , Flagelina , Humanos , Proteína Inibidora de Apoptose Neuronal/genética , Espécies Reativas de Oxigênio/metabolismo , Transdução de Sinais , Células THP-1 , Sistemas de Secreção Tipo III/metabolismo
17.
Elife ; 92020 10 19.
Artigo em Inglês | MEDLINE | ID: mdl-33074100

RESUMO

Bacteria of the genus Shigella cause shigellosis, a severe gastrointestinal disease that is a major cause of diarrhea-associated mortality in humans. Mice are highly resistant to Shigella and the lack of a tractable physiological model of shigellosis has impeded our understanding of this important human disease. Here, we propose that the differential susceptibility of mice and humans to Shigella is due to mouse-specific activation of the NAIP-NLRC4 inflammasome. We find that NAIP-NLRC4-deficient mice are highly susceptible to oral Shigella infection and recapitulate the clinical features of human shigellosis. Although inflammasomes are generally thought to promote Shigella pathogenesis, we instead demonstrate that intestinal epithelial cell (IEC)-specific NAIP-NLRC4 activity is sufficient to protect mice from shigellosis. In addition to describing a new mouse model of shigellosis, our results suggest that the lack of an inflammasome response in IECs may help explain the susceptibility of humans to shigellosis.


Assuntos
Proteínas Reguladoras de Apoptose/deficiência , Proteínas de Ligação ao Cálcio/deficiência , Suscetibilidade a Doenças/imunologia , Disenteria Bacilar/imunologia , Proteína Inibidora de Apoptose Neuronal/deficiência , Animais , Humanos , Inflamassomos/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Shigella/imunologia
18.
Immunol Rev ; 297(1): 67-82, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32729154

RESUMO

Cytosolic innate immune sensing is a cornerstone of innate immunity in mammalian cells and provides a surveillance system for invading pathogens and endogenous danger signals. The NAIP-NLRC4 inflammasome responds to cytosolic flagellin, and the inner rod and needle proteins of the type 3 secretion system of bacteria. This complex induces caspase-1-dependent proteolytic cleavage of the proinflammatory cytokines IL-1ß and IL-18, and the pore-forming protein gasdermin D, leading to inflammation and pyroptosis, respectively. Localized responses triggered by the NAIP-NLRC4 inflammasome are largely protective against bacterial pathogens, owing to several mechanisms, including the release of inflammatory mediators, liberation of concealed intracellular pathogens for killing by other immune mechanisms, activation of apoptotic caspases, caspase-7, and caspase-8, and expulsion of an entire infected cell from the mammalian host. In contrast, aberrant activation of the NAIP-NLRC4 inflammasome caused by de novo gain-of-function mutations in the gene encoding NLRC4 can lead to macrophage activation syndrome, neonatal enterocolitis, fetal thrombotic vasculopathy, familial cold autoinflammatory syndrome, and even death. Some of these clinical manifestations could be treated by therapeutics targeting inflammasome-associated cytokines. In addition, the NAIP-NLRC4 inflammasome has been implicated in the pathogenesis of colorectal cancer, melanoma, glioma, and breast cancer. However, no consensus has been reached on its function in the development of any cancer types. In this review, we highlight the latest advances in the activation mechanisms and structural assembly of the NAIP-NLRC4 inflammasome, and the functions of this inflammasome in different cell types. We also describe progress toward understanding the role of the NAIP-NLRC4 inflammasome in infectious diseases, autoinflammatory diseases, and cancer.


Assuntos
Doenças Transmissíveis , Neoplasias , Animais , Proteínas de Ligação ao Cálcio , Inflamassomos/metabolismo , Proteína Inibidora de Apoptose Neuronal/genética , Proteína Inibidora de Apoptose Neuronal/metabolismo
19.
Mol Aspects Med ; 76: 100863, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-32499055

RESUMO

In this review we give an overview of the NAIP/NLRC4 activation mechanism as well as the described roles of this inflammasome, with a focus on in vivo infection and pathology. After ligand recognition by NAIP sensor proteins the NAIP/NLRC4 inflammasome forms through oligomerization with the NLRC4 adaptor to activate Caspase-1. The activating ligands are intracellular bacterial flagellin or type-3 secretion system components, delivered by pathogens. In vivo experiments indicate a role in macrophages during lung, spleen and liver infection and systemic sepsis like conditions, as well as in intestinal epithelial cells. Upon NAIP/NLRC4 activation in the intestine, epithelial cell extrusion is triggered in addition to the canonical inflammasome outcomes of cytokine cleavage and pyroptosis. Human patients with auto-activating mutations in NLRC4 present with an autoinflammatory syndrome including enterocolitis. Although one of the better understood inflammasomes in terms of mechanism, tissue specific functions of NAIP/NLRC4 are only beginning to be understood.


Assuntos
Proteínas Adaptadoras de Sinalização CARD , Inflamassomos , Proteínas Adaptadoras de Sinalização CARD/metabolismo , Proteínas de Ligação ao Cálcio , Flagelina/metabolismo , Humanos , Imunidade Inata , Inflamassomos/metabolismo , Proteína Inibidora de Apoptose Neuronal/metabolismo
20.
Arch Biochem Biophys ; 688: 108366, 2020 07 30.
Artigo em Inglês | MEDLINE | ID: mdl-32387473

RESUMO

Preeclampsia (PE) is a pregnancy-related syndrome and has become the leading cause of maternal and neonatal morbidity and mortality. LncRNA has been elucidated to play critical roles in the phenotype of trophoblast cells. However, the effect of AK002210 has not been reported. We aim to investigate the effect of AK002210 on the phenotype of trophoblast cells. Quantitative reverse transcription PCR was used to assess the gene expression. CCK-8 assay was used to evaluate the cell proliferation. Transwell assay was performed to detect the migration and invasion of trophoblast cells. Luciferase assay and rescue experiment were carried out to verify the interaction between miR-590-3p and AK002210 as well as NLR family apoptosis inhibitory protein (NAIP). The results revealed that AK002210 promoted the proliferation, migration and invasion of trophoblast cell while AK002210 knockdown inhibited that. Mechanically, we found that AK002210 was targeted by miR-590-3p. Moreover, miR-590-3p also directly targets NAIP which served as a ceRNA of AK002210. Rescue experiment showed that miR-590-3p reversed the effect of AK002210 which further confirmed their interaction. Moreover, AK002210 was proved to participated in the regulation of ERK/MMP-2 signal axis. In conclusion, we found that AK002210 knockdown may play a critical role in the progression of PE via miR-590-3p/NAIP and ERK/MMP signaling. It has potential to be a novel prognostic or therapeutic marker of PE.


Assuntos
Movimento Celular/fisiologia , Proliferação de Células/fisiologia , Pré-Eclâmpsia/fisiopatologia , RNA Longo não Codificante/fisiologia , Transdução de Sinais/fisiologia , Trofoblastos/fisiologia , Apoptose/fisiologia , Linhagem Celular , Regulação para Baixo , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Feminino , Técnicas de Silenciamento de Genes , Humanos , Metaloproteinase 2 da Matriz/metabolismo , MicroRNAs/metabolismo , Proteína Inibidora de Apoptose Neuronal/metabolismo , Placenta/metabolismo , Pré-Eclâmpsia/metabolismo , Gravidez , RNA Longo não Codificante/genética , RNA Longo não Codificante/metabolismo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...