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The multi-pass transmembrane protein ACCELERATED CELL DEATH 6 (ACD6) is an immune regulator in Arabidopsis thaliana with an unclear biochemical mode of action. We have identified two loci, MODULATOR OF HYPERACTIVE ACD6 1 (MHA1) and its paralog MHA1-LIKE (MHA1L), that code for â¼7 kDa proteins, which differentially interact with specific ACD6 variants. MHA1L enhances the accumulation of an ACD6 complex, thereby increasing the activity of the ACD6 standard allele for regulating plant growth and defenses. The intracellular ankyrin repeats of ACD6 are structurally similar to those found in mammalian ion channels. Several lines of evidence link increased ACD6 activity to enhanced calcium influx, with MHA1L as a direct regulator of ACD6, indicating that peptide-regulated ion channels are not restricted to animals.
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Proteínas de Arabidopsis , Arabidopsis , Anquirinas/metabolismo , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Morte Celular , Canais Iônicos/genética , Canais Iônicos/metabolismo , Imunidade Vegetal/genéticaRESUMO
Although the cell membrane and cytoskeleton play essential roles in cellular morphogenesis, the interaction between the membrane and cytoskeleton is poorly understood. Cotton fibers are extremely elongated single cells, which makes them an ideal model for studying cell development. Here, we used the sphingolipid biosynthesis inhibitor, fumonisin B1 (FB1), and found that it effectively suppressed the myeloblastosis (MYB) transcription factor GhMYB86, thereby negatively affecting fiber elongation. A direct target of GhMYB86 is GhTUB7, which encodes the tubulin protein, the major component of the microtubule cytoskeleton. Interestingly, both the overexpression of GhMYB86 and GhTUB7 caused an ectopic microtubule arrangement at the fiber tips, and then leading to shortened fibers. Moreover, we found that GhMBE2 interacted with GhMYB86 and that FB1 and reactive oxygen species induced its transport into the nucleus, thereby enhancing the promotion of GhTUB7 by GhMYB86. Overall, we established a GhMBE2-GhMYB86-GhTUB7 regulation module for fiber elongation and revealed that membrane sphingolipids affect fiber elongation by altering microtubule arrangement.
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A key step in jasmonic acid (JA) signaling is the ligand-dependent assembly of a coreceptor complex comprising the F-box protein COI1 and JAZ transcriptional repressors. The assembly of this receptor complex results in proteasome-mediated degradation of JAZ repressors, which in turn bind and repress MYC transcription factors. Many studies on JAZs have been performed in Arabidopsis thaliana, but the function of JAZs in rice is largely unknown. To systematically reveal the function of OsJAZs, in this study, we compared the various phenotypes resulting from 13 OsJAZs via ectopic expression in Arabidopsis thaliana and the phenotypes of 12 AtJAZs overexpression (OE) lines. Phylogenetic analysis showed that the 25 proteins could be divided into three major groups. Yeast two-hybrid (Y2H) assays revealed that most OsJAZ proteins could form homodimers or heterodimers. The statistical results showed that the phenotypes of the OsJAZ OE plants were quite different from those of AtJAZ OE plants in terms of plant growth, development, and immunity. As an example, compared with other JAZ OE plants, OsJAZ11 OE plants exhibited a JA-insensitive phenotype and enhanced resistance to Pst DC3000. The protein stability after JA treatment of OsJAZ11 emphasized the specific function of the protein. This study aimed to explore the commonalities and characteristics of different JAZ proteins functions from a genetic perspective, and to screen genes with disease resistance value. Overall, the results of this study provide insights for further functional analysis of rice JAZ family proteins.
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Proteínas de Arabidopsis , Arabidopsis , Oryza , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Ciclopentanos/metabolismo , Expressão Ectópica do Gene , Regulação da Expressão Gênica de Plantas , Oryza/genética , Oryza/metabolismo , Oxilipinas/metabolismo , Filogenia , Plantas/metabolismo , Proteínas Repressoras/genética , Proteínas Repressoras/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismoRESUMO
Citrus Huanglongbing (HLB), caused by Candidatus Liberibacter asiaticus (Las), is one of the most destructive citrus diseases worldwide, yet how Las causes HLB is poorly understood. Here we show that a Las-secreted protein, SDE15 (CLIBASIA_04025), suppresses plant immunity and promotes Las multiplication. Transgenic expression of SDE15 in Duncan grapefruit (Citrus × paradisi) suppresses the hypersensitive response induced by Xanthomonas citri ssp. citri (Xcc) and reduces the expression of immunity-related genes. SDE15 also suppresses the hypersensitive response triggered by the Xanthomonas vesicatoria effector protein AvrBsT in Nicotiana benthamiana, suggesting that it may be a broad-spectrum suppressor of plant immunity. SDE15 interacts with the citrus protein CsACD2, a homolog of Arabidopsis (Arabidopsis thaliana) ACCELERATED CELL DEATH 2 (ACD2). SDE15 suppression of plant immunity is dependent on CsACD2, and overexpression of CsACD2 in citrus suppresses plant immunity and promotes Las multiplication, phenocopying overexpression of SDE15. Identification of CsACD2 as a susceptibility target has implications in genome editing for novel plant resistance against devastating HLB.
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Proteínas Reguladoras de Apoptose/fisiologia , Proteínas de Arabidopsis/fisiologia , Proteínas de Bactérias/fisiologia , Citrus sinensis/imunologia , Interações Hospedeiro-Patógeno/imunologia , Liberibacter/fisiologia , Oxirredutases/fisiologia , Proteínas de Bactérias/isolamento & purificação , Citrus sinensis/metabolismo , Imunidade Vegetal , Plantas Geneticamente ModificadasRESUMO
Microbial pathogen contamination is a leading cause of impairment for urban rivers and streams in Michigan. Reports on the ability of green infrastructure best management practices to remove microbial pathogens have been highly variable. This study evaluated the influence of a detention basin (Kreiser Pond) on microbial dynamics in the Plaster Creek watershed in West Michigan. High levels of fecal indicator bacteria and coliphage were documented in influent and effluent water, with significant increases in indicator microbe concentrations during storm events. In dry conditions, Kreiser Pond efficiently reduced the number of indicator microbes flowing through the basin. Rainfall volume had a greater influence on the diversity of bacteria than sampling location. Antibiotic resistance was prevalent in culturable E. coli from Kreiser Pond, demonstrating a potential public health risk and highlighting the need for identifying the ultimate sources of microbial pollution.
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Lagoas , Microbiologia da Água , Monitoramento Ambiental , Escherichia coli , Fezes , RiosRESUMO
The present study aimed to investigate the protective role of sirtuin 1 (SIRT1) and oxygen regulated protein 150 (ORP150) in a rat COPD model by inducing changes in ER stress and apoptosis. We separated 48 Sprague Dawley (SD) rats into four groups randomly: the control group, resveratrol group, COPD group and the resveratrol intervention group. Rats were challenged with cigarette smoke and lipopolysaccharide with resveratrol (a selective activator of SIRT1). The lung functions of the rats were measured and recorded. The expression levels of SIRT1 and ORP150 in lung tissues were examined by western blot and RTq PCR. The expression levels of the ER stress apoptosis-associated protein were determined .The apoptotic level of lung tissues was analyzed. The results suggest that SIRT1 attenuated apoptosis and ER stress in the lung tissues of rats with COPD. During this process, a positive correlation was identified between SIRT1 and ORP150.
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Apoptose , Estresse do Retículo Endoplasmático , Doença Pulmonar Obstrutiva Crônica/metabolismo , Sirtuína 1/metabolismo , Animais , Antioxidantes/farmacologia , Proteínas de Choque Térmico HSP70/genética , Proteínas de Choque Térmico HSP70/metabolismo , Lipopolissacarídeos/toxicidade , Pulmão/efeitos dos fármacos , Pulmão/metabolismo , Masculino , Doença Pulmonar Obstrutiva Crônica/etiologia , Ratos , Ratos Sprague-Dawley , Resveratrol/farmacologia , Sirtuína 1/genética , Poluição por Fumaça de Tabaco/efeitos adversosRESUMO
Chronic obstructive pulmonary disease (COPD) is partly characterized as epithelial-mesenchymal transition (EMT)-related airflow limitation. Extracellular vesicles (EVs) play crucial roles in the crosstalk between cells, affecting many diseases including COPD. Up to now, the roles of EVs in COPD are still debated. As we found in this investigation, COPD patients have higher miR-21 level in total serum EVs. EMT occurs in lungs of COPD mice. Furthermore, bronchial epithelial cells (BEAS-2B) could generate EVs with less miR-21 when treated with cigarette smoke extract (CSE), impacting less on the M2-directed macrophage polarization than the control-EVs (PBS-treated) according to EVs miR-21 level. Furthermore, the EMT processes in BEAS-2B cells were enhanced with the M2 macrophages proportion when co-cultured. Collectively, these results demonstrate that CSE-treated BEAS-2B cells could alleviate M2 macrophages polarization by modulated EVs, and eventually relieve the EMT process of BEAS-2B cells themselves under COPD pathogenesis, revealing a novel compensatory role of them in COPD.
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Brônquios/patologia , Polaridade Celular , Células Epiteliais/metabolismo , Transição Epitelial-Mesenquimal , Vesículas Extracelulares/metabolismo , Macrófagos/patologia , Doença Pulmonar Obstrutiva Crônica/patologia , Animais , Apoptose , Linhagem Celular , Fumar Cigarros , Modelos Animais de Doenças , Vesículas Extracelulares/ultraestrutura , Feminino , Humanos , Macrófagos/metabolismo , Masculino , Camundongos Endogâmicos C57BL , MicroRNAs/sangue , Pessoa de Meia-Idade , Doença Pulmonar Obstrutiva Crônica/sangueRESUMO
MicroRNAs and autophagy play important roles in chronic obstructive pulmonary disease (COPD). This study was designed to explore the role of microRNA-21 (miR-21) induced autophagy in COPD. Using the C57BL/6, miR-21-/- mice and human bronchial epithelial (16HBE) cell line, we found that in the lung tissues of mice, the level of autophagy in the COPD model group was significantly higher than that in the control group. However, compared to the COPD model, the level of autophagy was significantly lower in the miR-21-/- CSE+CS group. In the COPD model, miR-21 was overexpressed. Moreover, in human bronchial epithelial (16HBE) cells exposed to cigarette smoke extract (CSE), miR-21 expression was upregulated and autophagy was notably increased. In addition, pretreatment of 16HBE cells with miR-21 inhibitor significantly inhibited autophagy activity and decreased apoptosis, indicating that miR-21 is involved in CSE-induced autophagy and apoptosis. The results showed that miR-21 could increase autophagy and promote the apoptosis of 16HBE cells in COPD. This information contributes to our further understanding of COPD.
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Autofagia , MicroRNAs , Doença Pulmonar Obstrutiva Crônica/genética , Animais , Apoptose , Linhagem Celular , Fumar Cigarros/efeitos adversos , Humanos , Camundongos , Camundongos Endogâmicos C57BL , MicroRNAs/efeitos dos fármacos , Doença Pulmonar Obstrutiva Crônica/patologiaRESUMO
INTRODUCTION: Macrophages play an important role in chronic obstructive pulmonary disease (COPD). Cigarette smoke (CS) impairs autophagy in alveolar macrophages from COPD patients, and autophagic impairment leads to reduced clearance of protein aggregates, dysfunctional mitochondria, and defective bacterial delivery to lysosomes. However, the exact function of lung macrophage autophagy in the pathogenesis of CS-induced COPD remains largely unknown. METHODS: Western blot detected the expression of autophagy-related proteins induced by CSE. The model of COPD mice was established by CS exposure combined with CSE intraperitoneal injection. Double immunofluorescence was used to measure the CD206+LC3B+ cells. The morphological changes and effects on lung function were observed. Masson staining detected the changes in collagen fibers in lung tissue. The expression levels of E-cadherinb and N-cadherinb were detected by immunohistochemistry. Western blot detected the expression of ATP6V1E1 in lung tissue. RESULTS: At 24 hours of exposure to CSE, the expression levels of LC3B (microtubule-associated protein 1A/1B-light chain 3B) and P62 (nucleoporin 62) were highest at 1% CSE and AGT5 (nucleoporin 62) at 2.5% CSE; at 48 hours, the expression levels of LC3B, P62 and AGT5 were highest at 2.5% CSE, and as the intervention time increased.CD206+LC3B+ cells were significantly higher in the COPD group. Enhanced macrophage autophagy may promote emphysema formation and aggravate lung function damage. The expression of E-cadherinb in lung tissue of the COPD group was decreased, and N-cadherinb expression was increased; the expression of E-cadherinb was increased, and N-cadherinb expression was decreased in ATG5myeΔ COPD mice. The expression of ATP6V1E1 in the lung tissue was increased in the COPD group; ATP6V1E1 expression was decreased in the lung tissues of ATG5myeΔ COPD mice. CONCLUSIONS: CSE enhanced macrophage autophagy, leads to increased lung function impairment and collagenous fiber in lung tissue, as well as promotes epithelial-mesenchymal transition, and eventually leads to small airway remodeling, which may be achieved through the ATG5/ATP6V1E1 pathway.
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Xanthomonas oryzae pv. oryzicola (Xoc), which causes rice bacterial leaf streak, invades leaves mainly through stomata, which are often closed as a plant immune response against pathogen invasion. How Xoc overcomes stomatal immunity is unclear. Here, we show that the effector protein AvrRxo1, an ATP-dependent protease, enhances Xoc virulence and inhibits stomatal immunity by targeting and degrading rice OsPDX1 (pyridoxal phosphate synthase), thereby reducing vitamin B6 (VB6) levels in rice. VB6 is required for the activity of aldehyde oxidase, which catalyzes the last step of abscisic acid (ABA) biosynthesis, and ABA positively regulates rice stomatal immunity against Xoc. Thus, we provide evidence supporting a model in which a major bacterial pathogen inhibits plant stomatal immunity by directly targeting VB6 biosynthesis and consequently inhibiting the biosynthesis of ABA in guard cells to open stomata. Moreover, AvrRxo1-mediated VB6 targeting also explains the poor nutritional quality, including low VB6 levels, of Xoc-infected rice grains.
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Oryza , Proteínas de Bactérias , Oryza/genética , Oryza/metabolismo , Doenças das Plantas/microbiologia , Vitamina B 6 , XanthomonasRESUMO
OBJECTIVE: To understand the clinical characteristics of COVID-19 patients with clinically diagnosed bacterial co-infection (CDBC), and therefore contributing to their early identification and prognosis estimation. METHOD: 905 COVID-19 patients from 7 different centers were enrolled. The demography data, clinical manifestations, laboratory results, and treatments were collected accordingly for further analyses. RESULTS: Around 9.5% of the enrolled COVID-19 patients were diagnosed with CDBC. Older patients or patients with cardiovascular comorbidities have increased CDBC probability. Increased body temperature, longer fever duration, anhelation, gastrointestinal symptoms, illness severity, intensive care unit attending, ventilation treatment, glucocorticoid therapy, longer hospitalization time are correlated to CDBC. Among laboratory results, increased white blood cell counting (mainly neutrophil), lymphocytopenia, increased procalcitonin, erythrocyte sedimentation rate, C-reaction protein, D-dimer, blood urea nitrogen, lactate dehydrogenase, brain natriuretic peptide, myoglobin, blood sugar and decreased albumin are also observed, indicating multiple system functional damage. Radiology results suggested ground glass opacity mixed with high density effusion opacities and even pleural effusion. CONCLUSION: The aged COVID-19 patients with increased inflammatory indicators, worse lymphopenia and cardiovascular comorbidities are more likely to have clinically diagnosed bacterial co-infection. Moreover, they tend to have severer clinical manifestations and increased probability of multiple system functional damage.
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Infecções Bacterianas , COVID-19/epidemiologia , Coinfecção , Adulto , Idoso , Infecções Bacterianas/diagnóstico , Infecções Bacterianas/epidemiologia , Coinfecção/diagnóstico , Coinfecção/epidemiologia , Comorbidade , Diagnóstico Precoce , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Prognóstico , Índice de Gravidade de DoençaRESUMO
Chronic obstructive pulmonary disease (COPD) is a complex disease with multiple etiologies, while smoking is the most established one. The present study investigated the modulation of T-helper 17 (Th17) cell differentiation by the miR-21/Smad7/TGF-ß pathway, and their roles in COPD. Lung tissues were obtained from lung cancer patients with or without COPD who underwent lobotomy and the levels of miR-21, TGF-ß/Smad signaling molecules, RORγT, and other Th17-related cytokines were detected. Mouse COPD models were built by exposing both wild-type (WT) and miR-21-/- mice to cigarette smoke (CS) and cigarette smoke extract (CSE) intraperitoneal injection. Isolated primary CD4+ T cells were treated with either CS extract, miR-21 mimics or inhibitors, followed by measuring Th17 cells markers and the expression of TGF-ß/Smad signaling molecules and RORγT. Increased levels of miR-21, Smad7, phosphorylated (p)-Smad2, p-Smad3, TGF-ß, and Th17-related cytokines was detected in the lungs of COPD patients. Lung function in modeled WT mice, but not miR-21-/- ones, deteriorated and the number of inflammatory cells in the lung tissues increased compared to the control WT-mice. Moreover, primary CD4+ lymphocytes tend to differentiate into Th17 cells after the treatment with CSE or miR-21 mimics, and the expression of RORγT and the TGF-ß/Smad signaling were all increased, however miR-21 inhibitors worked reversely. Our findings demonstrated that Th17 cells increased under COPD pathogenesis and was partially modulated by the miR-21/Smad7/TGF-ß pathway.
Assuntos
MicroRNAs/genética , Membro 3 do Grupo F da Subfamília 1 de Receptores Nucleares/genética , Doença Pulmonar Obstrutiva Crônica/genética , Proteína Smad7/genética , Fator de Crescimento Transformador beta/genética , Animais , Linfócitos T CD4-Positivos , Diferenciação Celular/genética , Fumar Cigarros/efeitos adversos , Modelos Animais de Doenças , Humanos , Pulmão/metabolismo , Pulmão/patologia , Neoplasias Pulmonares/complicações , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/patologia , Ativação Linfocitária/efeitos dos fármacos , Ativação Linfocitária/genética , Camundongos , Doença Pulmonar Obstrutiva Crônica/complicações , Doença Pulmonar Obstrutiva Crônica/patologia , Transdução de Sinais , Fumaça/efeitos adversos , Células Th17/metabolismo , Células Th17/patologiaRESUMO
To analyze the clinical characteristics of re-positive discharged COVID-19 patients and find distinguishing markers. The demographic features, clinical symptoms, laboratory results, comorbidities, co-infections, treatments, illness severities and chest CT scan results of 267 patients were collected from 1st January to 15th February 2020. COVID-19 was diagnosed by RT-PCR. Clinical symptoms and nucleic acid test results were collected during the 14 days post-hospitalization quarantine. 30 out of 267 COVID-19 patients were detected re-positive during the post-hospitalization quarantine. Re-positive patients could not be distinguished by demographic features, clinical symptoms, laboratory results, comorbidities, co-infections, treatments, chest CT scan results or subsequent clinical symptoms. However, re-positive rate was found to be correlated to illness severity, according the Acute Physiology and Chronic Health Evaluation II (APACHE II) severity-of-disease classification system, and the confusion, urea, respiratory rate and blood pressure (CURB-65) score. Common clinical characteristics were not able to distinguish re-positive patients. However, severe and critical cases classified high according APACHE II and CURB-65 scores, were more likely to become re-positive after discharge.
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Betacoronavirus/genética , Infecções por Coronavirus/patologia , Pneumonia Viral/patologia , Adulto , Idoso , Betacoronavirus/isolamento & purificação , COVID-19 , China , Comorbidade , Infecções por Coronavirus/virologia , Feminino , Seguimentos , Humanos , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Pandemias , Alta do Paciente , Pneumonia Viral/virologia , Quarentena , RNA Viral/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , SARS-CoV-2 , Índice de Gravidade de Doença , Tórax/diagnóstico por imagem , Tomografia Computadorizada por Raios XRESUMO
The broadly conserved AvrE-family of type III effectors from gram-negative plant-pathogenic bacteria includes important virulence factors, yet little is known about the mechanisms by which these effectors function inside plant cells to promote disease. We have identified two conserved motifs in AvrE-family effectors: a WxxxE motif and a putative C-terminal endoplasmic reticulum membrane retention/retrieval signal (ERMRS). The WxxxE and ERMRS motifs are both required for the virulence activities of WtsE and AvrE, which are major virulence factors of the corn pathogen Pantoea stewartii subsp. stewartii and the tomato or Arabidopsis pathogen Pseudomonas syringae pv. tomato, respectively. The WxxxE and the predicted ERMRS motifs are also required for other biological activities of WtsE, including elicitation of the hypersensitive response in nonhost plants and suppression of defense responses in Arabidopsis. A family of type III effectors from mammalian bacterial pathogens requires WxxxE and subcellular targeting motifs for virulence functions that involve their ability to mimic activated G-proteins. The conservation of related motifs and their necessity for the function of type III effectors from plant pathogens indicates that disturbing host pathways by mimicking activated host G-proteins may be a virulence mechanism employed by plant pathogens as well.
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Proteínas de Bactérias/fisiologia , Pantoea/patogenicidade , Pseudomonas syringae/patogenicidade , Fatores de Virulência/fisiologia , Motivos de Aminoácidos/fisiologia , Arabidopsis/metabolismo , Arabidopsis/microbiologia , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Morte Celular , Retículo Endoplasmático/metabolismo , Membranas Intracelulares , Mutação , Pantoea/genética , Pantoea/metabolismo , Filogenia , Sinais Direcionadores de Proteínas , Pseudomonas syringae/genética , Pseudomonas syringae/metabolismo , Virulência , Fatores de Virulência/química , Fatores de Virulência/genética , Zea mays/citologia , Zea mays/metabolismo , Zea mays/microbiologiaRESUMO
Chronic obstructive pulmonary disease (COPD) is a multi-pathogenesis chronic lung disease. The mechanisms underlying COPD have not been adequately illustrated. Many reseachers argue that microRNAs (miRs) could play a crucial role in COPD. The classic animal model of COPD is both time consuming and costly. This study proposes a novel mice COPD model and explores the role of miR-21 in COPD. A total of 50 wide-type (WT) C57BL/6 mice were separated into five euqlly-sized groups-(1) control group (CG), (2) the novel combined method group (NCM, cigarette smoke (CS) exposure for 28 days combined with cigarette smoke extract (CSE) intraperitoneal injection), (3) the short-term CS exposure group (SCSE, CS exposure for 28 days), (4) the CSE intraperitoneal injection group (CSEII, 28 days CSE intraperitoneal injection), and (5) the long-term CS exposure group (LCSE, CS exposure).The body weight gain of mice were recorded and lung function tested once the modeling was done. The pathological changes and the inflammation level by hematoxylin eosin (H&E) staining and immunohistochemical staining (IHS) on the lung tissue sections were also evaluated. The level of miR-21 in the mice lungs of the mice across all groups was detected by RT-qPCR and the effects of miR-21 knock-down in modeled mice were observed. The mice in LCSE and NCM exhibited the most severe inflammation levels and pathological and pathophysiological changes; while the changes for the mice in SCSE and CSEII were less, they remained more severe than the mice in the CG. The level of miR-21 was found to be negatively correlated with lung functions. Moreover, knocking miR-21 down from the modeled mice, ameliorated all those tested COPD-related changes. Our novel modeling method detected virtually the same changes as those detected in the classic method in WT mice, but in less time and cost. Further, it was determined that the level of miR-21 in the lungs could be an indicator of COPD severity and blocking functions of miR-21 could be a potential treatment for early stage COPD.
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Despite impressive advances in the study of plant resistance to pathogens, little is known about the molecular basis of plant susceptibility to virulent pathogens. Recent progress in susceptible plant-Pseudomonas syringae interactions has provided a glimpse into the battles fought between plants and bacterial pathogens. A key step for pathogenesis appears to be the suppression of host defenses. Suppression of host defenses, including basal defense, gene-for-gene resistance and nonhost resistance, is a key step for pathogenesis. Defense suppression is mediated by bacterial effector proteins, which are secreted through the type III secretion system, and by coronatine, a bacterial toxin that structurally and functionally mimics methyl jasmonate, a plant defense signaling molecule.
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Doenças das Plantas/microbiologia , Plantas/imunologia , Pseudomonas syringae/fisiologia , Regulação da Expressão Gênica de Plantas , Imunidade Inata , Plantas/genética , Pseudomonas syringae/patogenicidade , Transdução de Sinais , VirulênciaRESUMO
BACKGROUND: COPD is a multi-pathogenesis disease mainly caused by smoking. A further understanding of the mechanism of smoking-related COPD might contribute to preventions and treatments of this disease in the early stages. This study was designed to identify the characteristics of M2 macrophages in COPD for a better understanding about their potential role. MATERIALS AND METHODS: COPD models were built in the C57BL/6 mouse by cigarette smoke (CS) exposure combined with intraperitoneal injection of cigarette smoke extract (CSE). The modeling efficiency was evaluated by lung function and hematoxylin and eosin (H&E) staining. The number of different macrophage phenotypes was detected by immunohistochemical staining (IHS) of CD206, CD86 and CD68 on the lung tissue paraffin section. The RAW264.7 cells were polarized toward the M2 phenotype by interleukin IL-4 and confirmed by a flow cytometer. The gene expression levels of TGF-ßRII, Smad2, Smad3 and Smad7 in CSE-treated M2 macrophages were detected by real-time reverse transcription polymerase chain reaction (RT-PCR). The expression levels of TGF-ß/Smad pathway-related makers (TGF-ßRII, p-Smad2, p-Smad3, Smad7 and TGF-ß) in alveolar M2 macrophages were detected by two consecutive paraffin section IHS. RESULTS: The COPD model is well established, which is confirmed by the lung function test and lung H&E staining. The whole number of macrophages and the ratio of M2/M1 phenotype are both increased (p<0.05). The level of CD206+ cells in IL-4-stimulated RAW264.7 cells is up to 93.4%, which is confirmed by a flow cytometer. The gene expression of TGF-ßRII, Smad2, Smad3 and Smad7 are all enhanced (p<0.05) in CES-treated M2 macrophages, which is detected by RT-PCR. The protein levels of TGF-ß/Smad pathway-related markers are all increased in alveolar M2 macrophages of the model group. CONCLUSION: This study found an increased deposition of alveolar M2 macrophages in the mouse COPD model and an increased expression level of TGF-ß/Smad pathway in M2 macrophages, both in vitro and in vivo, induced by CSE and/or CS exposure, indicating that M2 macrophages might contribute to COPD through changing of phenotype and TGF-ß/Smad pathway.
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Pulmão/metabolismo , Macrófagos Alveolares/metabolismo , Doença Pulmonar Obstrutiva Crônica/metabolismo , Animais , Antígenos CD/metabolismo , Antígenos de Diferenciação Mielomonocítica/metabolismo , Antígeno B7-2/metabolismo , Modelos Animais de Doenças , Interleucina-4/farmacologia , Lectinas Tipo C/metabolismo , Pulmão/imunologia , Pulmão/patologia , Macrófagos Alveolares/efeitos dos fármacos , Macrófagos Alveolares/imunologia , Macrófagos Alveolares/patologia , Receptor de Manose , Lectinas de Ligação a Manose/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Fenótipo , Fosforilação , Proteínas Serina-Treonina Quinases/genética , Proteínas Serina-Treonina Quinases/metabolismo , Doença Pulmonar Obstrutiva Crônica/imunologia , Doença Pulmonar Obstrutiva Crônica/patologia , Células RAW 264.7 , Receptor do Fator de Crescimento Transformador beta Tipo II , Receptores de Superfície Celular/metabolismo , Receptores de Fatores de Crescimento Transformadores beta/genética , Receptores de Fatores de Crescimento Transformadores beta/metabolismo , Transdução de Sinais , Proteína Smad2/genética , Proteína Smad2/metabolismo , Proteína Smad3/genética , Proteína Smad3/metabolismo , Proteína Smad7/genética , Proteína Smad7/metabolismoRESUMO
The enterobacterium Erwinia amylovora is a devastating plant pathogen causing necrotrophic fire blight disease of apple, pear, and other rosaceous plants. In an attempt to identify genes induced during infection of host plants, we identified and cloned a putative effector gene, avrRpt2EA. The deduced amino-acid sequence of the translated AvrRpt2EA protein is homologous to the effector protein AvrRpt2 previously reported in Pseudomonas syringae pv. tomato. These two proteins share 58% identity (70% similarity) in the functional domain; however, the secretion and translocation signal domain varied. The avrRpt2EA promoter region contains a typical 'hrp box,' which suggests that avrRpt2EA is regulated by the alternative sigma factor, HrpL. avrRpt2EA was detected in all E. amylovora strains tested but not in other closely related Erwinia species. An avrRpt2EA deletion mutant was reduced in its ability to cause systemic infection on immature pear fruits as compared with the wild-type strain, indicating that avrRpt2EA acts as a virulence factor on its native host. Growth of P. syringae pv. tomato DC3000 expressing avrRpt2EA was 10-fold higher than that of P. syringae pv. tomato DC3000 in an Arabidopsis rps2 mutant, indicating that avrRpt2EA promotes virulence of P. syringae pv. tomato DC3000 on Arabidopsis similar to P. syringae pv. tomato avrRpt2. When avrRpt2EA was expressed in P. syringae pv. tomato DC3000 in its native form, a weak hypersensitive response (HR) was induced in Arabidopsis; however, a hybrid protein containing the P. syringae pv. tomato avrRpt2 signal sequence, when expressed from the P syringae pv. tomato avrRpt2 promoter, caused a strong HR. Thus, the signal sequence and promoter of avrRpt2EA may affect its expression, secretion, or translocation, singly or in combination, in P. syringae pv. tomato DC3000. These results indicated that avrRpt2EA is genetically recognized by the RPS2 disease resistance gene in Arabidopsis when expressed in P. syringae pv. tomato DC3000. The results also suggested that although distinct pathogens such as E. amylovora and P. syringae may contain similar effector genes, expression and secretion of these effectors can be under specific regulation by the native pathogen.
Assuntos
Proteínas de Arabidopsis/fisiologia , Arabidopsis/microbiologia , Proteínas de Bactérias/fisiologia , Erwinia amylovora/patogenicidade , Pseudomonas syringae/genética , Pyrus/microbiologia , Sequência de Aminoácidos , Arabidopsis/anatomia & histologia , Arabidopsis/fisiologia , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Clonagem Molecular , Erwinia amylovora/genética , Erwinia amylovora/metabolismo , Dados de Sequência Molecular , Mutação , Folhas de Planta/anatomia & histologia , Folhas de Planta/microbiologia , Folhas de Planta/fisiologia , Regiões Promotoras Genéticas , Pyrus/anatomia & histologia , Pyrus/fisiologia , Proteínas Recombinantes de Fusão/metabolismo , Proteínas Recombinantes de Fusão/fisiologia , Alinhamento de SequênciaRESUMO
The type III secretion system is an essential virulence system used by many Gram-negative bacterial pathogens to deliver effector proteins into host cells. This review summarizes recent advancements in the understanding of the type III secretion system of Pseudomonas syringae, including regulation of the type III secretion genes, assembly of the Hrp pilus, secretion signals, the putative type III effectors identified to date, and their virulence action after translocation into plant cells.
Assuntos
Proteínas de Bactérias/metabolismo , Pseudomonas/metabolismo , Proteínas de Bactérias/genética , Regulação Bacteriana da Expressão Gênica , Modelos Biológicos , Chaperonas Moleculares/metabolismo , Plantas/metabolismo , Plantas/microbiologia , Pseudomonas/classificação , Pseudomonas/genética , Virulência/fisiologiaRESUMO
Acibenzolar-S-methyl (ASM, Actigard 50 WG), a synthetic inducer of systemic acquired resistance (SAR) and pathogenesis-related (PR) proteins, was evaluated for the control of fire blight on apple trees in the field and for PR protein gene expression in apple seedlings in the greenhouse. Expression of putative genes related to SAR induction was elevated in ASM-treated apple seedlings 2 to 7 days after treatment; levels of PR-1 and PR-8 RNA were increased 10-fold and PR-2 RNA was increased 100-fold in ASM-treated seedlings over levels in untreated seedlings. Spurs and shoots on Jonathan trees sprayed with ASM at 75 mg a.i./liter at pink and at weekly intervals thereafter had significantly less fire blight than untreated trees, both from natural infection and following artificial inoculation with the pathogen. Less fire blight was observed on trees sprayed weekly with ASM than on trees sprayed biweekly. The severity of fire blight on inoculated shoots of Fuji apple decreased with increasing rates of ASM (0 to 300 mg a.i./liter), and ASM combined with streptomycin showed enhanced activity over ASM at 75 mg a.i./liter alone. In general, ASM was not superior to streptomycin for fire blight control, but integrating a weekly schedule of ASM, preferably at 150 mg a.i./liter, with a schedule of streptomycin designed for blossom blight control appears promising for overall improvement in fire blight control.