RESUMO
The presence of DNA in the cytoplasm is normally a sign of microbial infections and is quickly detected by cyclic GMP-AMP synthase (cGAS) to elicit anti-infection immune responses. However, chronic activation of cGAS by self-DNA leads to severe autoimmune diseases for which no effective treatment is available yet. Here we report that acetylation inhibits cGAS activation and that the enforced acetylation of cGAS by aspirin robustly suppresses self-DNA-induced autoimmunity. We find that cGAS acetylation on either Lys384, Lys394, or Lys414 contributes to keeping cGAS inactive. cGAS is deacetylated in response to DNA challenges. Importantly, we show that aspirin can directly acetylate cGAS and efficiently inhibit cGAS-mediated immune responses. Finally, we demonstrate that aspirin can effectively suppress self-DNA-induced autoimmunity in Aicardi-Goutières syndrome (AGS) patient cells and in an AGS mouse model. Thus, our study reveals that acetylation contributes to cGAS activity regulation and provides a potential therapy for treating DNA-mediated autoimmune diseases.
Assuntos
DNA/imunologia , Nucleotidiltransferases/metabolismo , Tolerância a Antígenos Próprios/imunologia , Acetilação , Sequência de Aminoácidos , Animais , Aspirina/farmacologia , Doenças Autoimunes/genética , Doenças Autoimunes/imunologia , Doenças Autoimunes/metabolismo , Doenças Autoimunes do Sistema Nervoso/genética , Doenças Autoimunes do Sistema Nervoso/imunologia , Doenças Autoimunes do Sistema Nervoso/metabolismo , Autoimunidade , Linhagem Celular , DNA/genética , DNA/metabolismo , Modelos Animais de Doenças , Exodesoxirribonucleases/metabolismo , Células HEK293 , Células HeLa , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Modelos Moleculares , Mutação , Malformações do Sistema Nervoso/genética , Malformações do Sistema Nervoso/imunologia , Malformações do Sistema Nervoso/metabolismo , Nucleotidiltransferases/antagonistas & inibidores , Nucleotidiltransferases/química , Nucleotidiltransferases/genética , Células THP-1RESUMO
Cyclic GMP-AMP synthase (cGAS) is a key sensor responsible for cytosolic DNA detection. Here we report that GTPase-activating protein SH3 domain-binding protein 1 (G3BP1) is critical for DNA sensing and efficient activation of cGAS. G3BP1 enhanced DNA binding of cGAS by promoting the formation of large cGAS complexes. G3BP1 deficiency led to inefficient DNA binding by cGAS and inhibited cGAS-dependent interferon (IFN) production. The G3BP1 inhibitor epigallocatechin gallate (EGCG) disrupted existing G3BP1-cGAS complexes and inhibited DNA-triggered cGAS activation, thereby blocking DNA-induced IFN production both in vivo and in vitro. EGCG administration blunted self DNA-induced autoinflammatory responses in an Aicardi-Goutières syndrome (AGS) mouse model and reduced IFN-stimulated gene expression in cells from a patient with AGS. Thus, our study reveals that G3BP1 physically interacts with and primes cGAS for efficient activation. Furthermore, EGCG-mediated inhibition of G3BP1 provides a potential treatment for cGAS-related autoimmune diseases.
Assuntos
Doenças Autoimunes do Sistema Nervoso/metabolismo , DNA Helicases/metabolismo , Complexos Multiproteicos/metabolismo , Malformações do Sistema Nervoso/metabolismo , Nucleotidiltransferases/metabolismo , Proteínas de Ligação a Poli-ADP-Ribose/metabolismo , RNA Helicases/metabolismo , Proteínas com Motivo de Reconhecimento de RNA/metabolismo , Animais , Autoantígenos/imunologia , Autoantígenos/metabolismo , Doenças Autoimunes do Sistema Nervoso/tratamento farmacológico , Doenças Autoimunes do Sistema Nervoso/genética , Catequina/análogos & derivados , Catequina/uso terapêutico , Repetições Palindrômicas Curtas Agrupadas e Regularmente Espaçadas , Citosol/imunologia , Citosol/metabolismo , DNA/imunologia , DNA/metabolismo , DNA Helicases/antagonistas & inibidores , DNA Helicases/genética , Modelos Animais de Doenças , Exodesoxirribonucleases/genética , Células HEK293 , Células HeLa , Humanos , Interferons/metabolismo , Camundongos , Camundongos Knockout , Malformações do Sistema Nervoso/tratamento farmacológico , Malformações do Sistema Nervoso/genética , Fármacos Neuroprotetores/uso terapêutico , Fosfoproteínas/genética , Proteínas de Ligação a Poli-ADP-Ribose/antagonistas & inibidores , Proteínas de Ligação a Poli-ADP-Ribose/genética , Ligação Proteica , RNA Helicases/antagonistas & inibidores , RNA Helicases/genética , Proteínas com Motivo de Reconhecimento de RNA/antagonistas & inibidores , Proteínas com Motivo de Reconhecimento de RNA/genéticaRESUMO
Necroptosis is a form of regulated necrosis and is executed by MLKL when MLKL is engaged in triggering the rupture of cell plasma membrane. MLKL activation also leads to the protease, ADAMs-mediated ectodomain shedding of cell surface proteins of necroptotic cells. Tumor necroptosis often happens in advanced solid tumors, and blocking necroptosis by MLKL deletion in breast cancer dramatically reduces tumor metastasis. It has been suggested that tumor necroptosis affects tumor progression through modulating the tumor microenvironment. However, the exact mechanism by which tumor necroptosis promotes tumor metastasis remains elusive. Here, we report that the ectodomain shedding of cell surface proteins of necroptotic cells is critical for the promoting effect of tumor necroptosis in tumor metastasis through inhibiting the anti-tumor activity of T cells. We found that blocking tumor necroptosis by MLKL deletion led to the dramatic reduction of tumor metastasis and significantly elevated anti-tumor activity of tumor-infiltrating and peripheral blood T cells. Importantly, the increased anti-tumor activity of T cells is a key cause for the reduced metastasis as the depletion of CD8+ T cells completely restored the level of metastasis in the Mlkl KO mice. Interestingly, the levels of some soluble cell surface proteins including sE-cadherin that are known to promote metastasis are also dramatically reduced in MLKL null tumors/mice. Administration of ADAMs pan inhibitor reduces the levels of soluble cell surface proteins in WT tumors/mice and leads to the dramatic decrease in metastasis. Finally, we showed the sE-cadherin/KLRG1 inhibitory receptor is the major pathway for necroptosis-mediated suppression of the anti-tumor activity of T cells and the promotion of metastasis. Hence, our study reveals a novel mechanism of tumor necroptosis-mediated promotion of metastasis and suggests that tumor necroptosis and necroptosis-activated ADAMs are potential targets for controlling metastasis.
Assuntos
Neoplasias da Mama , Proteínas de Membrana , Necroptose , Metástase Neoplásica , Animais , Camundongos , Caderinas , Proteínas de Membrana/metabolismo , Camundongos Knockout , Proteínas Quinases , Proteína Serina-Treonina Quinases de Interação com Receptores/metabolismo , Proteína Serina-Treonina Quinases de Interação com Receptores/farmacologia , Microambiente Tumoral , Neoplasias da Mama/patologiaRESUMO
MicroRNAs are key regulators of many biological processes, including cell differentiation. Here we show that during human monocyte-macrophage differentiation, expression of the microRNAs miR-223, miR-15a and miR-16 decreased considerably, which led to higher expression of the serine-threonine kinase IKKalpha in macrophages. In macrophages, higher IKKalpha expression in conjunction with stabilization of the kinase NIK induced larger amounts of p52. Because of low expression of the transcription factor RelB in untreated macrophages, high p52 expression repressed basal transcription of both canonical and noncanonical NF-kappaB target genes. However, proinflammatory stimuli in macrophages resulted in greater induction of noncanonical NF-kappaB target genes. Thus, a decrease in certain microRNAs probably prevents macrophage hyperactivation yet primes the macrophage for certain responses to proinflammatory stimuli.
Assuntos
Diferenciação Celular/imunologia , Regulação da Expressão Gênica no Desenvolvimento , Quinase I-kappa B/imunologia , Quinase I-kappa B/metabolismo , Macrófagos/imunologia , MicroRNAs/imunologia , NF-kappa B/imunologia , Células Cultivadas , Técnicas de Silenciamento de Genes , Células HeLa , Humanos , Macrófagos/citologia , NF-kappa B/genética , Transdução de Sinais , Células U937 , Regulação para CimaRESUMO
ABSTRACT: Maxillary skeletal expansion (MSE) provides a new nonsurgical method for the treatment of patients with insufficient maxillary arch expansion width. In this study the aerodynamic changes of the upper airway after MSE in adult patients were explored based on three-dimensional reconstruction technology of cone-beam computed tomographic data and the numerical simulation technology of computational fluid dynamics. An upper airway experimental model was then created based on three-dimensional printing technology and tested in vitro to verify the reliability of the numerical simulation method. The comparison between numerical simulation and experimental results shows that the 2 results are in good agreement. The results of numerical simulation showed that the cross-sectional area of the upper airway was increased after MSE, the pressure and velocity of the upper airway were reduced, and airway resistance was also reduced during exhalation and inhalation. This study shows that MSE can effectively improve the airway dynamics of patients.
Assuntos
Técnica de Expansão Palatina , Faringe , Adulto , Tomografia Computadorizada de Feixe Cônico/métodos , Humanos , Maxila/diagnóstico por imagem , Nariz , Faringe/diagnóstico por imagem , Reprodutibilidade dos TestesRESUMO
The physiological function of the adaptor protein TRADD remains unclear because of the unavailability of a TRADD-deficient animal model. By generating TRADD-deficient mice, we found here that TRADD serves an important function in tumor necrosis factor receptor 1 (TNFR1) signaling by orchestrating the formation of TNFR1 signaling complexes. TRADD was essential for TNFR1 signaling in mouse embryonic fibroblasts but was partially dispensable in macrophages; abundant expression of the adaptor RIP in macrophages may have allowed some transmission of TNFR1 signals in the absence of TRADD. Although morphologically normal, TRADD-deficient mice were resistant to toxicity induced by TNF, lipopolysaccharide and polyinosinic-polycytidylic acid. TRADD was also required for TRIF-dependent Toll-like receptor signaling in mouse embryonic fibroblasts but not macrophages. Our findings definitively establish the biological function of TRADD in TNF signaling.
Assuntos
Transdução de Sinais , Proteína de Domínio de Morte Associada a Receptor de TNF/deficiência , Fator 1 Associado a Receptor de TNF/metabolismo , Receptores Toll-Like/metabolismo , Peptídeos e Proteínas Associados a Receptores de Fatores de Necrose Tumoral/fisiologia , Animais , Fibroblastos/metabolismo , Macrófagos/metabolismo , Camundongos , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Transdução de Sinais/efeitos dos fármacos , Proteína de Domínio de Morte Associada a Receptor de TNF/metabolismo , Peptídeos e Proteínas Associados a Receptores de Fatores de Necrose Tumoral/genética , Ubiquitina/metabolismoRESUMO
The regulation of apoptosis is critical for controlling tissue homeostasis and preventing tumor formation and growth. Reactive oxygen species (ROS) generation plays a key role in such regulation. Here, we describe a HIF-1 target, Vasn/ATIA (anti-TNFα-induced apoptosis), which protects cells against TNFα- and hypoxia-induced apoptosis. Through the generation of ATIA knockout mice, we show that ATIA protects cells from apoptosis through regulating the function of the mitochondrial antioxidant, thioredoxin-2, and ROS generation. ATIA is highly expressed in human glioblastoma, and ATIA knockdown in glioblastoma cells renders them sensitive to hypoxia-induced apoptosis. Therefore, ATIA is not only a HIF-1 target that regulates mitochondrial redox pathways but also a potentially diagnostic marker and therapeutic target in human glioblastoma.
Assuntos
Proteínas Reguladoras de Apoptose/fisiologia , Apoptose , Proteínas de Transporte/fisiologia , Fator 1 Induzível por Hipóxia/metabolismo , Proteínas de Membrana/fisiologia , Tiorredoxinas/metabolismo , Animais , Proteínas Reguladoras de Apoptose/análise , Proteínas Reguladoras de Apoptose/genética , Proteínas de Transporte/química , Proteínas de Transporte/genética , Hipóxia Celular , Linhagem Celular Tumoral , Membrana Celular/metabolismo , Glioblastoma/metabolismo , Humanos , Proteínas de Membrana/análise , Proteínas de Membrana/química , Proteínas de Membrana/genética , Camundongos , Mitocôndrias/metabolismo , Oxirredução , Tiorredoxinas/genéticaRESUMO
NADPH oxidases (NOXs) are involved in inflammation, angiogenesis, tumor growth, and osteoclast differentiation. However, the role of NOX1 and NOX2 in macrophage differentiation and tumor progression is still elusive. Here we report that NOX1 and NOX2 are critical for the differentiation of monocytes to macrophages, the polarization of M2-type but not M1-type macrophages, and the occurrence of tumor-associated macrophages (TAMs). We found that deletion of both NOX1 and NOX2 led to a dramatic decrease in ROS production in macrophages and resulted in impaired efficiency in monocyte-to-macrophage differentiation and M2-type macrophage polarization. We further showed that NOX1 and NOX2 were critical for the activation of the MAPKs JNK and ERK during macrophage differentiation and that the deficiency of JNK and ERK activation was responsible for the failure of monocyte-to-macrophage differentiation, in turn affecting M2 macrophage polarization. Furthermore, we demonstrated that the decrease in M2 macrophages and TAMs, concomitant with the reduction of cytokine and chemokine secretion, contributed to the delay in wound healing and the inhibition of tumor growth and metastasis in NOX1/2 double knockout mice compared with WT mice. Collectively, these data provide direct evidence that NOX1 and NOX2 deficiency impairs macrophage differentiation and the occurrence of M2-type TAMs during tumor development.
Assuntos
Diferenciação Celular/imunologia , Macrófagos/imunologia , Glicoproteínas de Membrana/imunologia , Monócitos/imunologia , NADH NADPH Oxirredutases/imunologia , NADPH Oxidases/imunologia , Espécies Reativas de Oxigênio/imunologia , Animais , Diferenciação Celular/genética , Quimiocinas/genética , Quimiocinas/imunologia , MAP Quinases Reguladas por Sinal Extracelular/genética , MAP Quinases Reguladas por Sinal Extracelular/imunologia , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Sistema de Sinalização das MAP Quinases/genética , Sistema de Sinalização das MAP Quinases/imunologia , Macrófagos/enzimologia , Glicoproteínas de Membrana/genética , Glicoproteínas de Membrana/metabolismo , Camundongos , Camundongos Knockout , Monócitos/enzimologia , NADH NADPH Oxirredutases/genética , NADH NADPH Oxirredutases/metabolismo , NADPH Oxidase 1 , NADPH Oxidase 2 , NADPH Oxidases/genética , NADPH Oxidases/metabolismo , Espécies Reativas de Oxigênio/metabolismoRESUMO
In many physiological and disease processes, TGF-beta usurps branches of MAP kinase pathways in conjunction with Smads to induce apoptosis and epithelial-to-mesenchymal transition, but the detailed mechanism of how a MAP kinase cascade is activated by TGF-beta receptors is not clear. We report here that TRAF6 is specifically required for the Smad-independent activation of JNK and p38, and its carboxyl TRAF homology domain physically interacts with TGF-beta receptors. TGF-beta induces K63-linked ubiquitination of TRAF6 and promotes association between TRAF6 and TAK1. Our results indicate that TGF-beta activates JNK and p38 through a mechanism similar to that operating in the interleukin-1beta/Toll-like receptor pathway.
Assuntos
Proteínas Quinases JNK Ativadas por Mitógeno/metabolismo , Fator 6 Associado a Receptor de TNF/metabolismo , Fator de Crescimento Transformador beta/farmacologia , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo , Animais , Apoptose/efeitos dos fármacos , Linhagem Celular , Ativação Enzimática/efeitos dos fármacos , Epitélio/efeitos dos fármacos , Epitélio/metabolismo , Humanos , Lisina/metabolismo , MAP Quinase Quinase Quinases/metabolismo , Mesoderma/efeitos dos fármacos , Mesoderma/metabolismo , Camundongos , Ligação Proteica/efeitos dos fármacos , Receptores de Fatores de Crescimento Transformadores beta/metabolismo , Transdução de Sinais/efeitos dos fármacos , Proteínas Smad/metabolismo , Ubiquitinação/efeitos dos fármacosRESUMO
Tumor necrosis factor (TNF) is an important inflammatory cytokine and induces many cellular responses, including inflammation, cell proliferation, apoptosis, and necrosis. It is known that receptor interacting protein (RIP) kinases, RIP1 and RIP3, are key effectors of TNF-induced necrosis, but little is known about how these two RIP kinases mediate this process, although reactive oxygen species (ROS) generation and JNK activation have been suggested to be two downstream events of RIP kinases. Here we report the identification of mixed lineage kinase domain-like, MLKL, as a key RIP3 downstream component of TNF-induced necrosis. Through screening a kinase/phosphatase shRNA library in human colon adenocarcinoma HT-29 cells, we found that knockdown of MLKL blocked TNF-induced necrosis. Our data suggest that MLKL functions downstream of RIP1 and RIP3 and is recruited to the necrosome through its interaction with RIP3. Finally, we found that MLKL is required for the generation of ROS and the late-phase activation of JNK during TNF-induced necrosis. However, because these two events are not involved in TNF-induced necrosis in HT-29 cells, the target of MLKL during TNF-induced necrosis remains elusive. Taken together, our study suggests that MLKL is a key RIP3 downstream component of TNF-induced necrotic cell death.
Assuntos
Necrose , Proteínas Quinases/metabolismo , Proteína Serina-Treonina Quinases de Interação com Receptores/metabolismo , Fator de Necrose Tumoral alfa/fisiologia , Sequência de Bases , Linhagem Celular , Primers do DNA , Ativação Enzimática , Humanos , MAP Quinase Quinase 4/metabolismo , Fosforilação , Reação em Cadeia da Polimerase , Espécies Reativas de Oxigênio/metabolismoRESUMO
Monocytes are programmed to undergo apoptosis in the absence of stimulation. Stimuli that promote monocyte-macrophage differentiation not only cause cellular changes, but also prevent the default apoptosis of monocytes. In the present study, we demonstrate that autophagy is induced when monocytes are triggered to differentiate and that the induction of autophagy is pivotal for the survival and differentiation of monocytes. We also show that inhibition of autophagy results in apoptosis of cells that are engaged in differentiation. We found that the differentiation signal releases Beclin1 from Bcl-2 by activating JNK and blocks Atg5 cleavage, both of which are critical for the induction of autophagy. Preventing autophagy induction hampers differentiation and cytokine production; therefore, autophagy is an important transition from monocyte apoptosis to differentiation.
Assuntos
Autofagia/fisiologia , Diferenciação Celular/fisiologia , Macrófagos/citologia , Monócitos/citologia , Animais , Western Blotting , Células Cultivadas , Citometria de Fluxo , Humanos , Imunoprecipitação , Camundongos , Camundongos Endogâmicos C57BL , Microscopia Confocal , Microscopia Eletrônica de Transmissão , Reação em Cadeia da Polimerase em Tempo Real , Transdução de Sinais/fisiologiaRESUMO
Isocitrate dehydrogenase (IDH)-mutant gliomas have distinctive metabolic and biological traits that may render them susceptible to targeted treatments. Here, by conducting a high-throughput drug screen, we pinpointed a specific susceptibility of IDH-mutant gliomas to zotiraciclib (ZTR). ZTR exhibited selective growth inhibition across multiple IDH-mutant glioma in vitro and in vivo models. Mechanistically, ZTR at low doses suppressed CDK9 and RNA Pol II phosphorylation in IDH-mutant cells, disrupting mitochondrial function and NAD+ production, causing oxidative stress. Integrated biochemical profiling of ZTR kinase targets and transcriptomics unveiled that ZTR-induced bioenergetic failure was linked to the suppression of PIM kinase activity. We posit that the combination of mitochondrial dysfunction and an inability to adapt to oxidative stress resulted in significant cell death upon ZTR treatment, ultimately increasing the therapeutic vulnerability of IDH-mutant gliomas. These findings prompted a clinical trial evaluating ZTR in IDH-mutant gliomas towards precision medicine ( NCT05588141 ). Highlights: Zotiraciclib (ZTR), a CDK9 inhibitor, hinders IDH-mutant glioma growth in vitro and in vivo . ZTR halts cell cycle, disrupts respiration, and induces oxidative stress in IDH-mutant cells.ZTR unexpectedly inhibits PIM kinases, impacting mitochondria and causing bioenergetic failure.These findings led to the clinical trial NCT05588141, evaluating ZTR for IDH-mutant gliomas.
RESUMO
The current paradigm of noncanonical NF-κB signaling suggests that the loss of TRAF2, TRAF3 or cIAP1 and cIAP2 leads to stabilization of NF-κB-inducing kinase (NIK) to activate the noncanonical pathway. Although a crucial role of RIP1 in the TNFα-induced canonical NF-κB pathway has been well established, its involvement in noncanonical activation of NF-κB through the TNFR1 receptor, is unknown. Here we show that TNFα is capable of activating the noncanonical NF-κB pathway, but that activation of this pathway is negatively regulated by RIP1. In the absence of RIP1, TNFR1 stimulation leads to activation of the noncanonical NF-κB pathway through TRAF2 degradation, leading to NIK stabilization, IKKα phosphorylation and the processing of p100 to generate p52. Thus although RIP1(-/-) mouse embryonic fibroblasts are sensitive at early time points to cell death induced by TNFα, probably as a result of lack of canonical NF-κB activation, the late activation of the noncanonical NF-κB pathway protects the remaining cells from further cell death. The TNFR1-dependent noncanonical NF-κB activation in RIP1(-/-) cells suggests that there is functional interplay between the two NF-κB pathways during TNFR1 signaling, which might regulate the number and kinds of NF-κB transcription factors and thus finely control NF-κB-dependent gene transcription.
Assuntos
Proteínas Ativadoras de GTPase/metabolismo , NF-kappa B/metabolismo , Fator 2 Associado a Receptor de TNF/metabolismo , Fator de Necrose Tumoral alfa/metabolismo , Animais , Linhagem Celular , Proteínas Ativadoras de GTPase/genética , Humanos , Camundongos , Camundongos Knockout , NF-kappa B/genética , Ligação Proteica , Estabilidade Proteica , Transdução de Sinais , Fator 2 Associado a Receptor de TNF/química , Fator 2 Associado a Receptor de TNF/genética , Fator de Necrose Tumoral alfa/genéticaRESUMO
TNFR-associated death domain protein (TRADD) is a key effector protein of TNFR1 signaling. However, the role of TRADD in other death receptor (DR) signaling pathways, including DR3, has not been completely characterized. Previous studies using overexpression systems suggested that TRADD is recruited to the DR3 complex in response to the DR3 ligand, TNF-like ligand 1A (TL1A), indicating a possible role in DR3 signaling. Using T cells from TRADD knockout mice, we demonstrate in this study that the response of both CD4(+) and CD8(+) T cells to TL1A is dependent upon the presence of TRADD. TRADD knockout T cells therefore lack the appropriate proliferative response to TL1A. Moreover, in the absence of TRADD, both the stimulation of MAPK signaling and activation of NF-κB in response to TL1A are dramatically reduced. Unsurprisingly, TRADD is required for recruitment of receptor interacting protein 1 and TNFR-associated factor 2 to the DR3 signaling complex and for the ubiquitination of receptor interacting protein 1. Thus, our findings definitively establish an essential role of TRADD in DR3 signaling.
Assuntos
Ativação Linfocitária/imunologia , Membro 25 de Receptores de Fatores de Necrose Tumoral/imunologia , Transdução de Sinais/imunologia , Linfócitos T/imunologia , Proteína de Domínio de Morte Associada a Receptor de TNF/imunologia , Membro 15 da Superfamília de Ligantes de Fatores de Necrose Tumoral/imunologia , Animais , Western Blotting , Separação Celular , Ensaio de Desvio de Mobilidade Eletroforética , Citometria de Fluxo , Imunoprecipitação , Camundongos , Camundongos Knockout , Membro 25 de Receptores de Fatores de Necrose Tumoral/metabolismo , Linfócitos T/metabolismo , Proteína de Domínio de Morte Associada a Receptor de TNF/metabolismo , Membro 15 da Superfamília de Ligantes de Fatores de Necrose Tumoral/metabolismoRESUMO
This paper presents a new segmentation-based algorithm for oil spill feature extraction from Synthetic Aperture Radar (SAR) intensity images. The proposed algorithm combines a Voronoi tessellation, Bayesian inference and Markov Chain Monte Carlo (MCMC) scheme. The shape and distribution features of dark spots can be obtained by segmenting a scene covering an oil spill and/or look-alikes into two homogenous regions: dark spots and their marine surroundings. The proposed algorithm is applied simultaneously to several real SAR intensity images and simulated SAR intensity images which are used for accurate evaluation. The results show that the proposed algorithm can extract the shape and distribution parameters of dark spot areas, which are useful for recognizing oil spills in a further classification stage.
RESUMO
Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) is a member of the TNF superfamily. TRAIL is promising for anticancer therapy because it induces apoptosis in cancer cells with little or no toxicity to normal cells; hence, TRAIL-receptor agonists are currently undergoing clinical trials for cancer treatment. However, many molecular signaling mechanisms in TRAIL signaling are not completely characterized. The functions of adaptor proteins, including TNF-receptor-associated death domain protein (TRADD) and receptor-interacting protein-1 (RIP1) in TRAIL signaling have been controversial. We demonstrate that while wild-type mouse embryonic fibroblasts (MEFs) are completely resistant to TRAIL-induced apoptosis, MEFs derived from Tradd(-/-) mice are hypersensitive to TRAIL (IC(50)~0.5 nM rmTRAIL, 24 h), an effect also seen in primary keratinocytes treated with TRAIL/CHX. Restoration of TRADD in Tradd(-/-) MEFs restores TRAIL resistance, indicating that TRADD plays a survival role in TRAIL signaling. We show that TRADD is recruited to the TRAIL-receptor complex, and RIP1 recruitment is mediated by TRADD. While early activation of the MAP kinase ERK is deficient in Tradd(-/-) cells, the main mechanism for enhanced TRAIL sensitivity is likely due to increased recruitment of FADD to the receptor complex, indicating that TRADD may limit FADD binding within the receptor complex and also mediate RIP1-dependent nonapoptotic signaling events, thus reducing caspase activation and subsequent apoptosis. These novel findings have potential implications for cancer therapy using TRAIL-receptor agonists.
Assuntos
Transdução de Sinais/fisiologia , Proteína de Domínio de Morte Associada a Receptor de TNF/fisiologia , Ligante Indutor de Apoptose Relacionado a TNF/farmacologia , Animais , Apoptose/fisiologia , Proteína de Domínio de Morte Associada a Fas/metabolismo , Proteínas Ativadoras de GTPase/metabolismo , Humanos , Camundongos , Receptores do Ligante Indutor de Apoptose Relacionado a TNF/agonistasRESUMO
Necroptosis is currently attracting the attention of the scientific community for its broad implications in inflammatory diseases and cancer. However, detecting ongoing necroptosis in vivo under both experimental and clinical disease conditions remains challenging. The technical barrier lies in four aspects, namely tissue sampling, real-time in vivo monitoring, specific markers, and distinction between different types of cell death. In this review, we presented the latest methodological advances for in vivo necroptosis identification. The advances highlighted the multi-parameter flow cytometry, sA5-YFP tool, radiolabeled Annexin V/Duramycin, Gallium-68-labeled IRDye800CW contrast agent, and SMART platform in vivo. We also discussed the up-to-date research models in studying necroptosis, particularly the mice models for manipulating and monitoring necroptosis. Based on these recent advances, this review aims to provide some advice on current necroptosis techniques and approaches.
RESUMO
Necroptosis, a form of programmed necrotic cell death, is a gatekeeper of host defense against certain pathogen invasions. The deregulation of necroptosis is also a key factor of many inflammatory diseases. Recent studies have revealed an important role of necroptosis in tumorigenesis and metastasis and imply the potential of targeting necroptosis as a novel cancer therapy. While its molecular mechanism has been well studied, details of the regulation and function of necroptosis of tumor cells in tumorigenesis and metastasis only began to emerge recently, and we discuss these herein.
Assuntos
Necroptose , Proteína Serina-Treonina Quinases de Interação com Receptores , Apoptose/genética , Humanos , Necroptose/genética , Necrose , Proteínas Quinases/metabolismo , Proteína Serina-Treonina Quinases de Interação com Receptores/metabolismoRESUMO
Necroptosis occurs predominantly in the center of late-stage tumors and necroptotic cells are dispersed and difficult to be detected by Western blotting of key markers without enrichment by microdissection. To overcome these obstacles, this protocol provides a detailed immunohistochemistry-oriented approach including the steps of tumor isolation from mouse mammary tumor models, necrotic region identification by H&E staining, and necroptosis detection through examining mixed lineage kinase domain-like protein (MLKL) phosphorylation. This protocol could be applied to other types of solid tumors. For complete details on the use and execution of this protocol, please refer to Baik et al. (2021).
Assuntos
Neoplasias Mamárias Animais , Necroptose , Animais , Camundongos , Necrose/patologia , Fosforilação , Proteínas Quinases/metabolismo , Fatores de Transcrição/metabolismoRESUMO
Cross talk between NF-kappaB and c-Jun N-terminal kinases (JNKs) has been implicated in the cell life and death decision under various stresses. Functional suppression of JNK activation by NF-kappaB has recently been proposed as a key cellular survival mechanism and contributes to cancer cells escaping from apoptosis. We provide a novel scenario of the proapoptotic role of IkappaB kinase beta (IKKbeta)-NF-kappaB, which can act as the activator of the JNK pathway through the induction of GADD45alpha for triggering MKK4/JNK activation, in response to the stimulation of arsenite, a cancer therapeutic reagent. This effect of IKKbeta-NF-kappaB is dependent on p50 but not the p65/relA NF-kappaB subunit, which can increase the stability of GADD45alpha protein through suppressing its ubiquitination and proteasome-dependent degradation. IKKbeta-NF-kappaB can therefore either activate or suppress the JNK cascade and consequently mediate pro- or antiapoptotic effects, depending on the manner of its induction. Furthermore, the NF-kappaB p50 subunit can exert a novel regulatory function on protein modification independent of the classical NF-kappaB transcriptional activity.