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1.
Front Microbiol ; 15: 1391453, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38863748

RESUMO

Mycoplasma pneumoniae (M. pneumoniae, Mp) is a cell wall-deficient microorganism known to cause chronic respiratory infections in both children and adults. Nucleotide-binding oligomerization domain-containing protein 2 (NOD2) is an intracellular pattern recognition receptor primarily responsible for identifying muramyl dipeptide (MDP) found in bacterial cell walls. Previous experiments have demonstrated that Mycoplasma ovipneumoniae induces macrophage autophagy through NOD2. In this study, we conducted RNA-seq analysis on macrophages infected with M. pneumoniae and observed an up-regulation in the expression of genes associated with the NOD2 signaling pathway. Mechanistic investigations further revealed the involvement of the NOD2 signaling pathway in the inflammatory response of macrophages activated by M. pneumoniae. We utilized GST pull-down technology in conjunction with liquid chromatography-tandem mass spectrometry (LC-MS/MS) to pinpoint the M. pneumoniae proteins that interact with NOD2. Additionally, co-immunoprecipitation (Co-IP) and immunofluorescence co-localization techniques were used to confirm the interaction between DUF16 protein and NOD2. We found that DUF16 protein can enter macrophages and induce macrophage inflammatory response through the NOD2/RIP2/NF-κB pathway. Notably, the region spanning amino acids 13-90 was identified as a critical region necessary for DUF16-induced inflammation. This research not only broadens our comprehension of the recognition process of the intracellular receptor NOD2, but also deepens our understanding of the development of M. pneumoniae infection.

2.
Int J Mol Sci ; 24(10)2023 May 11.
Artigo em Inglês | MEDLINE | ID: mdl-37239946

RESUMO

Mycoplasma pneumoniae (M. pneumoniae, Mp) is an intracellular pathogen that causes pneumonia, tracheobronchitis, pharyngitis, and asthma in humans and can infect and survive in the host cells leading to excessive immune responses. Extracellular vesicles (EVs) from host cells carry components of pathogens to recipient cells and play a role in intercellular communication during infection. However, there is limited knowledge on whether EVs derived from M. pneumoniae-infected macrophages play as intercellular messengers and functional mechanisms. In this study, we establish a cell model of M. pneumoniae-infected macrophages that continuously secrete EVs to further asses their role as intercellular messengers and their functional mechanisms. Based on this model, we determined a method for isolating the pure EVs from M. pneumoniae-infected macrophages, which employs a sequence of operations, including differential centrifugation, filtering, and ultracentrifugation. We identified EVs and their purity using multiple methods, including electron microscopy, nanoparticle tracking analysis, Western blot, bacteria culture, and nucleic acid detection. EVs from M. pneumoniae-infected macrophages are pure, with a 30-200 nm diameter. These EVs can be taken up by uninfected macrophages and induce the production of tumor necrosis factor (TNF)-α, interleukin (IL)-1ß, IL-6, and IL-8 through the nuclear factor (NF)-κB, and mitogen-activated protein kinases (MAPK) signals pathway. Moreover, the expression of inflammatory cytokines induced by EVs relies on TLR2-NF-κB/JNK signal pathways. These findings will help us better understand a persistent inflammatory response and cell-to-cell immune modulation in the context of M. pneumoniae infection.


Assuntos
Vesículas Extracelulares , NF-kappa B , Humanos , NF-kappa B/metabolismo , Sistema de Sinalização das MAP Quinases , Mycoplasma pneumoniae/metabolismo , Receptor 2 Toll-Like/metabolismo , Transdução de Sinais , Macrófagos/metabolismo , Fator de Necrose Tumoral alfa/metabolismo , Vesículas Extracelulares/metabolismo
3.
Sheng Wu Gong Cheng Xue Bao ; 39(1): 248-261, 2023 Jan 25.
Artigo em Chinês | MEDLINE | ID: mdl-36738214

RESUMO

Mycoplasma pneumoniae is the most common pathogen of respiratory tract infection in children and adults. Clinical observation shows that M. pneumoniae infection can cause massive mucus secretion in the respiratory tract, which makes the breathing of patients difficult. Studies have shown that M. pneumoniae infection can cause massive secretion of mucin 5AC (MUC5AC). Adhesin P1 plays an important role in the pathogenesis of M. pneumoniae infection by mediating the adhesion of pathogens to host cells, and the C-terminal residues of P1 (P1-C) are immunogenic. This study investigated the molecular mechanism of Wnt/ß-catenin signaling pathway inhibitor Dickkopf-1 (DKK1) in the secretion of MUC5AC in mouse airway epithelial cells (MAECs) induced by P1-C. Scanning electron microscope and hematoxylin-eosin staining were used to observe the effect of P1-C on mucus secretion of MAECs. Protein chip was used to detect the secretion of cytokines and analyse the enrichment of related signaling pathways induced by P1-C in MAECs. Periodic acid schiff stain (PAS) staining, Tunel staining and Masson staining were used to detect the damage of the lungs of mouse exposed to P1-C. Immunohistochemistry was used to detect the secretion of MUC5AC expression, and Western blotting was used to reveal the molecular mechanism of DKK1-regulated secretion of MUC5AC induced by P1-C protein in MACES. The results showed that P1-C induced the massive secretion of mucus and inflammatory factors in MAECs. During P1-C infection, DKK1 down-regulated janus kinase 2 (JAK2), phosphorylation signaling and transcription activator 1 (p-STAT1) and phosphorylation signaling and activator of transcription 3 (p-STAT3) expression. Overexpression of DKK1 significantly up-regulated the expression of MUC5AC repressor transcription factor fork-head box protein A2 (FOXA2). At the same time, the expression of MUC5AC induced by P1-C was inhibited significantly. It is speculated that DKK1 can effectively reduce the secretion of MUC5AC in MAECs induced by P1-C by inhibiting the JAK/STAT1-STAT3 signaling pathway and up-regulating the expression of FOXA2.


Assuntos
Mucina-5AC , Mycoplasma pneumoniae , Animais , Camundongos , Células Epiteliais , Pulmão , Mucina-5AC/genética , Mucina-5AC/metabolismo , Mycoplasma pneumoniae/metabolismo , Transdução de Sinais
4.
Mol Immunol ; 153: 60-74, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36444819

RESUMO

Mycoplasma pneumoniae (M. pneumoniae) is the most common pathogen of respiratory tract infections in both children and adults. M. pneumoniae P1 adhesin plays an important role in the pathogenesis of M. pneumoniae infection by mediating the attachment of pathogen to host cells. The inoculation of C-terminal residuals of P1 (P1-C) showed a protective role from M. pneumoniae infection. Accumulated evidence suggests that the Wnt/ß-Catenin signaling is implicated in regulation of inflammatory responses to bacterial infections. However, mechanisms underlying the regulatory roles of Wnt signaling in host cells in response to M. pneumoniae infections are incompletely understood. In the present study, the impact and molecular mechanism of Wnt/ß-catenin signaling in immune responses induced by M. pneumoniae P1-C were investigated. The results demonstrated that the P1-C could activate Wnt/ß-catenin and Toll-like receptor (TLR) signaling in primary mouse airway epithelial cells cultured in an air-liquid interface (ALI) state. Interestingly, the inhibition of Wnt/ß-catenin signaling by an adenovirus-mediated Wnt inhibitor Dickkopf-1 (Dkk1) gene transduction alleviated the P1-C induced inflammation fibrosis in mouse lung, accompanied by the reduced expression of epithelial mesenchymal transition (EMT) markers. Mechanistical analysis further demonstrated that the Dkk1 could suppress the expression of JAK2/STAT1-STAT3 and Caspase3, 8/Bax signaling in mouse lung tissues. In vitro study further revealed that XAV939, a small molecule of Wnt/ß-catenin inhibitor, inhibited the P1-C-activated TLR4/MyD88 signaling and cytokine productions in primary mouse airway ALI epithelial cells. This study thus provides an insight into the function of Wnt/ß-catenin signaling in regulation of the pathogenesis of M. pneumoniae infection, suggesting that targeting Wnt/ß-catenin signaling by gene transduction of Dkk1, or pharmacological molecules of inhibitor may be a promised approach that worthy of further investigation in the treatment of M. pneumoniae pneumonia.


Assuntos
Mycoplasma pneumoniae , Pneumonia Bacteriana , Via de Sinalização Wnt , Animais , Camundongos , beta Catenina/metabolismo , Células Epiteliais/metabolismo , Inflamação/metabolismo , Pulmão/metabolismo , Mycoplasma pneumoniae/metabolismo , Pneumonia Bacteriana/metabolismo
5.
Int J Mol Sci ; 23(19)2022 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-36233330

RESUMO

Bovine respiratory disease (BRD) continues to pose a serious threat to the cattle industry, resulting in substantial economic losses. As a multifactorial disease, pathogen infection and respiratory microbial imbalance are important causative factors in the occurrence and development of BRD. Integrative analyses of 16S rRNA sequencing and metabolomics allow comprehensive identification of the changes in microbiota and metabolism associated with BRD, making it possible to determine which pathogens are responsible for the disease and to develop new therapeutic strategies. In our study, 16S rRNA sequencing and metagenomic analysis were used to describe and compare the composition and diversity of nasal microbes in healthy cattle and cattle with BRD from different farms in Yinchuan, Ningxia, China. We found a significant difference in nasal microbial diversity between diseased and healthy bovines; notably, the relative abundance of Mycoplasma bovis and Pasteurella increased. This indicated that the composition of the microbial community had changed in diseased bovines compared with healthy ones. The data also strongly suggested that the reduced relative abundance of probiotics, including Pasteurellales and Lactobacillales, in diseased samples contributes to the susceptibility to bovine respiratory disease. Furthermore, serum metabolomic analysis showed altered concentrations of metabolites in BRD and that a significant decrease in lactic acid and sarcosine may impair the ability of bovines to generate energy and an immune response to pathogenic bacteria. Based on the correlation analysis between microbial diversity and the metabolome, lactic acid (2TMS) was positively correlated with Gammaproteobacteria and Bacilli and negatively correlated with Mollicutes. In summary, microbial communities and serum metabolites in BRD were characterized by integrative analysis. This study provides a reference for monitoring biomarkers of BRD, which will be critical for the prevention and treatment of BRD in the future.


Assuntos
Doenças dos Bovinos , Microbiota , Transtornos Respiratórios , Doenças Respiratórias , Animais , Bovinos , Cromatografia Gasosa , Ácido Láctico , Metabolômica , Microbiota/genética , RNA Ribossômico 16S/genética , Doenças Respiratórias/veterinária , Sarcosina
6.
Int J Mol Sci ; 23(17)2022 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-36077142

RESUMO

Rhodococcus equi (R. equi) is a Gram-positive coccobacillus that causes pneumonia in foals of less than 3 months, which have the ability of replication in macrophages. The ability of R. equi persist in macrophages is dependent on the virulence plasmid pVAPA. Gram-positive extracellular vesicles (EVs) carry a variety of virulence factors and play an important role in pathogenic infection. There are few studies on R. equi-derived EVs (R. equi-EVs), and little knowledge regarding the mechanisms of how R. equi-EVs communicate with the host cell. In this study, we examine the properties of EVs produced by the virulence strain R. equi 103+ (103+-EVs) and avirulenct strain R. equi 103− (103−-EVs). We observed that 103+-EVs and 103−-EVs are similar to other Gram-positive extracellular vesicles, which range from 40 to 260 nm in diameter. The 103+-EVs or 103−-EVs could be taken up by mouse macrophage J774A.1 and cause macrophage cytotoxicity. Incubation of 103+-EVs or 103−-EVs with J774A.1 cells would result in increased expression levels of IL-1ß, IL-6, and TNF-α. Moreover, the expression of TLR2, p-NF-κB, p-p38, and p-ERK were significantly increased in J774A.1 cells stimulated with R. equi-EVs. In addition, we presented that the level of inflammatory factors and expression of TLR2, p-NF-κB, p-p38, and p-ERK in J774A.1 cells showed a significant decreased when incubation with proteinase K pretreated-R. equi-EVs. Overall, our data indicate that R. equi-derived EVs are capable of mediating inflammatory responses in macrophages via TLR2-NF-κB/MAPK pathways, and R. equi-EVs proteins were responsible for TLR2-NF-κB/MAPK mediated inflammatory responses in macrophage. Our study is the first to reveal potential roles for R. equi-EVs in immune response in R. equi-host interactions and to compare the differences in macrophage inflammatory responses mediated by EVs derived from virulent strain R. equi and avirulent strain R. equi. The results of this study have improved our knowledge of the pathogenicity of R. equi.


Assuntos
Infecções por Actinomycetales , Vesículas Extracelulares , Rhodococcus equi , Infecções por Actinomycetales/metabolismo , Infecções por Actinomycetales/veterinária , Animais , Vesículas Extracelulares/metabolismo , Cavalos , Macrófagos/metabolismo , Camundongos , NF-kappa B/metabolismo , Rhodococcus equi/genética , Receptor 2 Toll-Like/genética , Receptor 2 Toll-Like/metabolismo
7.
Sheng Wu Gong Cheng Xue Bao ; 38(3): 855-867, 2022 Mar 25.
Artigo em Chinês | MEDLINE | ID: mdl-35355459

RESUMO

As a malleable and novel tool for antigen recognition and modulation, nanobodies have the advantages of small size, easiness of expression, screening and modification, as well as high affinity and stability. Nanobodies are capable of recognizing more cryptic antigenic epitopes that are difficult to be recognized by traditional antibodies, making them increasingly used in the diagnosis and treatment of various diseases and assays. Nanobodies are also playing an irreplaceable role in the basic research. This review summarized the recent development of nanobodies and their derivatives in the detection of small molecules, pathogenic microorganisms and diagnosis of diseases, as well as in the fields of targeted therapies, cellular and molecular imaging. Broad prospects of nanobodies in the field of protein conformation studies were also reviewed.


Assuntos
Anticorpos de Domínio Único
8.
J Bacteriol ; 202(20)2020 09 23.
Artigo em Inglês | MEDLINE | ID: mdl-32778560

RESUMO

Mycoplasma ovipneumoniae belongs to Mycoplasma, a genus containing the smallest self-replicating microorganisms, and causes infectious pleuropneumonia in goats and sheep. Nucleotide-binding oligomerization domain-containing protein (NOD2), an intracellular pattern recognition receptor, interacts with muramyl dipeptide (MDP) to recognize bacterial peptidoglycans and is involved in autophagy induction. However, there have been no reports about NOD recognition of mycoplasmas or M. ovipneumoniae-induced autophagy. In this study, we sought to determine the role of NOD2 in M. ovipneumoniae-induced autophagy using Western blotting, immunofluorescence, real-time PCR (RT-PCR), and color-changing unit (CCU) analysis. M. ovipneumoniae infection markedly increased NOD2 but did not increase NOD1 expression in RAW 264.7 cells. Treating RAW 264.7 cells with MDP significantly increased colocalization of M. ovipneumoniae and LC3, whereas treatment with NOD inhibitor, NOD-IN-1, decreased colocalization of M. ovipneumoniae and LC3. Furthermore, suppressing NOD2 expression with small interfering RNA (siRNA)-NOD2 failed to trigger M. ovipneumoniae-induced autophagy by detecting autophagy markers Atg5, beclin1, and LC3-II. In addition, M. ovipneumoniae infection significantly increased the phosphorylated c-Jun NH2-terminal kinase (p-JNK)/JNK, p-Bcl-2/Bcl-2, beclin1, Atg5, and LC3-II ratios in RAW 264.7 cells. Treatment with JNK inhibitor, SP600126, or siRNA-NOD2 did not increase this reaction. These findings suggested that M. ovipneumoniae infection activated NOD2, and both NOD2 and JNK pathway activation promoted M. ovipneumoniae-induced autophagy. This study provides new insight into the NOD2 reorganization mechanism and the pathogenesis of M. ovipneumoniae infection.IMPORTANCEM. ovipneumoniae, which lacks a cell wall, causes infectious pleuropneumonia in goats and sheep. In the present study, we focused on the interaction between NOD and M. ovipneumoniae, as well as its association with autophagy. We showed for the first time that NOD2 was activated by M. ovipneumoniae even when peptidoglycans were not present. We also observed that both NOD2 and JNK pathway activation promoted M. ovipneumoniae-induced autophagy.


Assuntos
Autofagia , Sistema de Sinalização das MAP Quinases , Macrófagos/microbiologia , Mycoplasma ovipneumoniae/patogenicidade , Proteína Adaptadora de Sinalização NOD2/metabolismo , Animais , Camundongos , Fosforilação , Células RAW 264.7
9.
Animals (Basel) ; 10(8)2020 Aug 11.
Artigo em Inglês | MEDLINE | ID: mdl-32796682

RESUMO

Myostatin (MSTN) is a member of the transforming growth factor beta superfamily and is a negative regulator of myogenesis. It has been shown to function by controlling the proliferation of myoblasts. MSTN inhibition is considered as a promising treatment for promoting animal growth in livestock. Nanobodies, a special antibody discovered in camel, have arisen as an alternative to conventional antibodies and have shown great potential when used as tools in different biotechnology fields, such as diagnostics and therapy. In this study, we examined the effect of MSTN inhibition by RMN on the muscle growth of mice. The results showed that RMN could specifically detect and bind MSTN, as well as inhibit MSTN activity. A significant increase in skeletal muscle mass was observed after intramuscular injection of RMN into mice. Enhanced muscle growth occurred because of myofiber hypertrophy. These results offer a promising approach to enhance muscle growth that warrants further investigation in domestic animals.

10.
J Sci Food Agric ; 99(9): 4383-4390, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30851058

RESUMO

BACKGROUND: The variable domain of camelid heavy-chain antibodies (VHH) is increasingly being adapted to detect small molecules in various matrices. The insecticide carbaryl is widely used in agriculture while its residues have posed a threat to food safety and human health. RESULTS: VHHs specific for carbaryl were generated from an alpaca immunized with the hapten CBR1 coupled to keyhole limpet hemocyanin. An enzyme-linked immunosorbent assay (ELISA) based on the VHH C1 and the coating antigen CBR2-BSA was developed for the detection of carbaryl in cereals. This assay, using an optimized assay buffer (pH 6.5) containing 10% methanol and 0.8% NaCl, has a half-maximum signal inhibition concentration of 5.4 ng mL-1 and a limit of detection (LOD) of 0.3 ng mL-1 for carbaryl, and shows low cross reactivity (≤0.8%) with other tested carbamates. The LOD of carbaryl using the VHH-based ELISA was 36 ng g-1 in rice and maize and 72 ng g-1 in wheat. Recoveries of carbaryl in spiked rice, maize and wheat samples were in the range of 81-106%, 96-106% and 83-113%, respectively. Relative standard deviations of repeatability and intra-laboratory reproducibility were in the range of 0.8-9.2% and 2.9-9.7%, respectively. CONCLUSION: The VHH-based ELISA was highly effective in detecting carbaryl in cereal samples after simple sample extraction and dilution. © 2019 Society of Chemical Industry.


Assuntos
Carbaril/análise , Ensaio de Imunoadsorção Enzimática/métodos , Inseticidas/análise , Triticum/química , Zea mays/química , Animais , Camelídeos Americanos , Grão Comestível/química , Contaminação de Alimentos/análise , Cadeias Pesadas de Imunoglobulinas/análise , Cadeias Pesadas de Imunoglobulinas/imunologia , Limite de Detecção , Anticorpos de Cadeia Única/análise , Anticorpos de Cadeia Única/imunologia
11.
Sheng Wu Gong Cheng Xue Bao ; 33(7): 1085-1090, 2017 Jul 25.
Artigo em Chinês | MEDLINE | ID: mdl-28869728

RESUMO

Camelidae can produce a unique antibody that lacks light chain called variable heavy chain domain, also known as nanobodies. This antibody contains only one variable region, with high affinity, high stability, strong tissue penetration, efficient expression. Besides, their toxicity and immunogenicity are both low to be used for both therapeutic and diagnostic applications, as well as research tools. In this review, we discuss how nanobody has been explored as therapeutics in oncology, and provide ideas for the further development of nanobody.


Assuntos
Camelidae/imunologia , Neoplasias/terapia , Anticorpos de Domínio Único/farmacologia , Animais , Humanos
12.
Mol Immunol ; 62(1): 150-8, 2014 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-24995397

RESUMO

The emerging roles of microRNAs (miRNAs) in regulating immune responses have attracted increasing attention in recent years; and the alveolar macrophages (AMs) are the main targets of mycobacterial infection, which play a pivotal role in the pathogenesis of Mycobacterium tuberculosis infection. However, the immunoregulatory role of miRNAs in AMs has not been fully demonstrated. In this study, we find that miR-124 is up-regulated in the peripheral leukocytes of patients with pulmonary tuberculosis; furthermore, the expression miR-124 can be induced upon Mycobacterium bovis Bacillus Calmette-Guerin (BCG) infection in both RAW264.7 AM cells in vitro and murine AMs in vivo. Mechanistically, miR-124 is able to modulate toll-like receptor (TLR) signaling activity in RAW264.7 cells in response to BCG infection. In this regard, multiple components of TLR signaling cascade, including the TLR6, myeloid differentiation factor 88 (MyD88), TNFR-associated factor 6 and tumor necrosis factor-α are directly targeted by miR-124. In addition, both overexpression of TLR signaling adaptor MyD88 and BCG infection are able to augment miR-124 transcription, while MyD88 expression silenced by small interfering RNA dramatically suppresses miR-124 expression in AMs in vitro. Moreover, the abundance of miR-124 transcript in murine AMs of MyD88 deficient mice is significantly less than that of their wild-type or heterozygous littermates; and the BCG infection fails to induce miR-124 expression in the lung of MyD88 deficient mouse. These results indicate a negative regulatory role of miR-124 in fine-tuning inflammatory response in AMs upon mycobacterial infection, in part through a mechanism by directly targeting TLR signaling.


Assuntos
Macrófagos Alveolares/imunologia , MicroRNAs/fisiologia , Receptores Toll-Like/imunologia , Tuberculose Pulmonar/imunologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Animais , Células Cultivadas , Feminino , Humanos , Macrófagos Alveolares/microbiologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Pessoa de Meia-Idade , Mycobacterium bovis/imunologia , Fator 88 de Diferenciação Mieloide/genética , Fator 88 de Diferenciação Mieloide/metabolismo , Transdução de Sinais/genética , Tuberculose Pulmonar/genética , Adulto Jovem
13.
Int J Mol Sci ; 15(3): 5045-62, 2014 Mar 21.
Artigo em Inglês | MEDLINE | ID: mdl-24663056

RESUMO

Apoptosis of alveolar macrophages following Mycobacterium tuberculosis infection have been demonstrated to play a central role in the pathogenesis of tuberculosis. In the present study, we found that Wnt/ß-catenin signaling possesses the potential to promote macrophage apoptosis in response to mycobacterial infection. In agreement with other findings, an activation Wnt/ß-catenin signaling was observed in murine macrophage RAW264.7 cells upon Mycobacterium bovis Bacillus Calmette-Guerin (BCG) infection at a multiple-of-infection of 10, which was accompanied with up-regulation of pro-inflammatory cytokines TNF-α and IL-6 production. However, the BCG-induced TNF-α and IL-6 secretion could be significantly reduced when the cells were exposed to a canonical Wnt signaling ligand, Wnt3a. Importantly, the activation of Wnt/ß-catenin signaling was able to further promote apoptosis in BCG-infected RAW264.7 cells in part by a mitochondria-dependent apoptosis pathway. Immunoblotting analysis further demonstrated that Wnt/ß-catenin signaling-induced cell apoptosis partly through a caspase-dependent apoptosis mechanism by down-regulation of anti-apoptotic protein Mcl-1, and up-regulation of pro-apoptotic proteins Bax and cleaved-caspase-3, as well as enhancement of caspase-3 activity in BCG-infected RAW264.7 cells. These data may imply an underlying mechanism of alveolar macrophages in response to mycobacterial infection, by which the pathogen induces Wnt/ß-catenin signaling activation, which in turn represses mycobacterium-trigged inflammatory responses and promotes mycobacteria-infected cell apoptosis.


Assuntos
Apoptose , Caspases/metabolismo , Macrófagos/metabolismo , Transdução de Sinais , Via de Sinalização Wnt , beta Catenina/metabolismo , Animais , Caspase 3/metabolismo , Linhagem Celular , Citometria de Fluxo , Interações Hospedeiro-Patógeno , Immunoblotting , Interleucina-6/metabolismo , Macrófagos/microbiologia , Macrófagos/ultraestrutura , Potencial da Membrana Mitocondrial , Camundongos , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão , Mycobacterium bovis/fisiologia , Proteína de Sequência 1 de Leucemia de Células Mieloides/metabolismo , Fator de Necrose Tumoral alfa/metabolismo , Proteína X Associada a bcl-2/metabolismo
14.
Mol Immunol ; 59(2): 128-35, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-24603120

RESUMO

Increasing evidence has demonstrated that the epithelial cells in the lung play crucial roles in regulating certain inflammatory responses by modulating Wnt signaling during microbial infection. However, the anti-microbial functions of Wnt signaling in alveolar epithelial cells remain elusive. In this report, we show that Wnt/ß-catenin signaling is repressed in A549 alveolar epithelial cells during a Toll-like receptor ligand stimulation with Mycobacterium bovis Bacillus Calmette-Guerin (BCG) or lipopolysaccharide (LPS). In addition to activating TLR signaling, a stimulation of BCG or LPS led to the up-regulation of a Wnt receptor Frizzled-1, cytosolic GSK3ß and Axin, and the down-regulation of nuclear ß-catenin, lymphoid enhancer factor 1 and transcription factor 4. While an enhancement of ß-catenin activity suppressed the TLR signal response, and substantially led to alleviate the TLR ligand-induced pro-inflammatory responses. Importantly, gain and loss of function studies by overexpressing or silencing of TLR signaling adaptor, myeloid differentiation primary response gene 88 (MyD88) further demonstrated an inverse relationship between TLR signaling and canonical Wnt signaling in A549 cells. These data imply that Wnt/ß-catenin signaling acts as a negative feedback loop to suppress inflammation in alveolar epithelial cells, and averts cell injury from excessive inflammatory reactions. This study thus reveals a novel immunoregulatory mechanism in alveolar epithelial cells in response to bacterial infection.


Assuntos
Células Epiteliais/imunologia , Fator 88 de Diferenciação Mieloide/metabolismo , Alvéolos Pulmonares/imunologia , Proteínas Wnt/metabolismo , beta Catenina/metabolismo , Proteína Axina/biossíntese , Fatores de Transcrição de Zíper de Leucina e Hélice-Alça-Hélix Básicos/biossíntese , Linhagem Celular , Regulação para Baixo , Células Epiteliais/metabolismo , Receptores Frizzled/biossíntese , Quinase 3 da Glicogênio Sintase/biossíntese , Glicogênio Sintase Quinase 3 beta , Humanos , Inflamação/imunologia , Lipopolissacarídeos/imunologia , Pulmão/imunologia , Fator 1 de Ligação ao Facilitador Linfoide/biossíntese , Mycobacterium bovis/imunologia , Fator 88 de Diferenciação Mieloide/biossíntese , Fator 88 de Diferenciação Mieloide/genética , Alvéolos Pulmonares/metabolismo , Interferência de RNA , RNA Interferente Pequeno , Mucosa Respiratória/imunologia , Fator de Transcrição 4 , Fatores de Transcrição/biossíntese , Regulação para Cima , Via de Sinalização Wnt/imunologia
15.
Cancers (Basel) ; 4(4): 1318-32, 2012 Dec 04.
Artigo em Inglês | MEDLINE | ID: mdl-24213508

RESUMO

In this study, the anti-proliferative and anticancer activity of azithromycin (AZM) was examined. In the presence of AZM, cell growth was inhibited more effectively in Hela and SGC-7901 cancer cells, relative to transformed BHK-21 cells. The respective 50% inhibition of cell growth (IC50) values for Hela, SGC-7901 and BHK-21 were 15.66, 26.05 and 91.00 µg/mL at 72 h post incubation, indicative of a selective cytotoxicity against cancer cells. Cell apoptosis analysis using Hoechst nuclear staining and annexin V-FITC binding assay further demonstrated that AZM was capable of inducing apoptosis in both cancer cells and transformed cells. The apoptosis induced by AZM was partly through a caspase-dependent mechanism with an up-regulation of apoptotic protein cleavage PARP and caspase-3 products, as well as a down-regulation of anti-apoptotic proteins, Mcl-1, bcl-2 and bcl-X1. More importantly, a combination of AZM and a low dose of the common anti-cancer chemotherapeutic agent vincristine (VCR), produced a selectively synergistic effect on apoptosis of Hela and SGC-7901 cells, but not BHK-21 cells. In the presence of 12.50 µg/mL of VCR, the respective IC50 values of Hela, SGC-7901 and BHK-21 cells to AZM were reduced to 9.47 µg/mL, 8.43 µg/mL and 40.15 µg/mL at 72 h after the incubation, suggesting that the cytotoxicity of AZM had a selective anti-cancer effect on cancer over transformed cells in vitro. These results imply that AZM may be a potential anticancer agent for use in chemotherapy regimens, and it may minimize side effects via reduction of dosage and enhancing the effectiveness common chemotherapeutic drugs.

16.
J Cell Biochem ; 105(1): 136-46, 2008 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-18465785

RESUMO

In flowering plants, pollen formation depends on the differentiation and interaction of two cell types in the anther: the reproductive cells, called microsporocytes, and somatic cells that form the tapetum. Previously, we cloned a pollen specific gene, zm401, from a cDNA library generated from the mature pollen of Zea mays. Expression of partial cDNA of zm401 in maize and ectopic expression of zm401 in tobacco suggested it may play a role in anther development. Here we present the expression and functional characterization of this pollen specific gene in maize. Zm401 is expressed primarily in the anthers (tapetal cells as well as microspores) in a developmentally regulated manner. That is, it is expressed from floret forming stage, increasing in concentration up to mature pollen. Knockdown of zm401 significantly affected the expression of ZmMADS2, MZm3-3, and ZmC5, critical genes for pollen development; led to aberrant development of the microspore and tapetum, and finally male-sterility. Zm401 possesses highly conserved sequences and evolutionary conserved stable RNA secondary structure in monocotyledon. These data show that zm401 could be one of the key growth regulators in anther development, and functions as a short-open reading-frame mRNA (sORF mRNA) and/or noncoding RNA (ncRNA).


Assuntos
Flores/crescimento & desenvolvimento , Flores/metabolismo , Fases de Leitura Aberta/genética , RNA não Traduzido/genética , Zea mays/crescimento & desenvolvimento , Zea mays/metabolismo , Flores/genética , Regulação da Expressão Gênica de Plantas , Dados de Sequência Molecular , Conformação de Ácido Nucleico , Fenótipo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas , RNA Mensageiro/genética , Zea mays/genética
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