RESUMO
Patients with ataxia-telangiectasia (A-T) lack a functional ATM kinase protein and exhibit defective repair of DNA double-stranded breaks and response to oxidative stress. We show that CRISPR/Cas9-assisted gene correction combined with piggyBac (PB) transposon-mediated excision of the selection cassette enables seamless restoration of functional ATM alleles in induced pluripotent stem cells from an A-T patient carrying compound heterozygous exonic missense/frameshift mutations, and from a patient with a homozygous splicing acceptor mutation of an internal coding exon. We show that the correction of one allele restores expression of ~ 50% of full-length ATM protein and ameliorates DNA damage-induced activation (auto-phosphorylation) of ATM and phosphorylation of its downstream targets, KAP-1 and H2AX. Restoration of ATM function also normalizes radiosensitivity, mitochondrial ROS production and oxidative-stress-induced apoptosis levels in A-T iPSC lines, demonstrating that restoration of a single ATM allele is sufficient to rescue key ATM functions. Our data further show that despite the absence of a functional ATM kinase, homology-directed repair and seamless correction of a pathogenic ATM mutation is possible. The isogenic pairs of A-T and gene-corrected iPSCs described here constitute valuable tools for elucidating the role of ATM in ageing and A-T pathogenesis.
Assuntos
Proteínas Mutadas de Ataxia Telangiectasia/genética , Ataxia Telangiectasia/prevenção & controle , Dano ao DNA , Reparo do DNA , Células-Tronco Pluripotentes Induzidas/citologia , Mutação , Estresse Oxidativo , Ataxia Telangiectasia/etiologia , Ataxia Telangiectasia/patologia , Proteínas Mutadas de Ataxia Telangiectasia/metabolismo , Células Cultivadas , Humanos , Células-Tronco Pluripotentes Induzidas/metabolismo , Fosforilação , Recuperação de Função FisiológicaRESUMO
The mechanism of the sterile inflammatory response in the respiratory tract induced by exposure to sterile particles has not been fully elucidated. The aim of our study is to explore the earlier events in initiating inflammatory response at molecular and cellular level in primary cultured human airway epithelial cells (AEC) exposed to silica particles in order to provide information for earlier diagnosis and prevention of silica particle-induced toxicity as well as possible information on the genesis of silicosis. We isolated primary AEC from three healthy adults and treated them with silica particles at different concentrations for 48 h. We found evidence for silica-induced inflammasome activation by the co-localization of Caspase-1 and NLRP3, as well as increased levels of IL-1ß and IL-18. Lactate dehydrogenase and NucGreen analysis proved the occurrence of pyroptosis. High throughput mRNA sequencing showed that the inflammatory response and NF-κB signaling pathways were significantly enriched in gene ontology and Kyoto encyclopedia of genes and genomes analysis, and pyroptosis-related genes were up-regulated. The miR-455-3p and five lncRNAs (LOC105375913, NEAT1, LOC105375181, LOC100506098, and LOC105369370) were verified as key factors related to the mechanism by ceRNA network analysis. LOC105375913 was first discovered to be associated with inflammation in AEC. These data suggest that microcrystalline silica can induce significant inflammation and pyroptosis in human primary AEC through NLRP3 inflammasome pathway and NF-κB signaling pathway at both the gene and protein levels, and the possible mechanism could be miR-455-3p mediated ceRNA hypothesis. Our data provide a method for the studies of the respiratory toxicity of fine particulate matter and the pathogenesis of early silicosis. The miR-455-3p and five lncRNAs related ceRNA network might be the toxicity mechanism of microcrystalline silica particles to AEC.
Assuntos
MicroRNAs , Piroptose , Células Epiteliais , Humanos , Inflamassomos/genética , MicroRNAs/genética , Proteína 3 que Contém Domínio de Pirina da Família NLR/genética , Sistema Respiratório , Dióxido de Silício/toxicidadeRESUMO
Silica dust particles are representative of air pollution and long-term inhalation of silicon-containing dust through the respiratory tract can cause pulmonary fibrosis. Epithelial-mesenchymal transformation (EMT) plays an important role in the development of fibrosis. This process can relax cell-cell adhesion complexes and enhance cell migration and invasion properties of these cells. Dysregulation of microRNA-34c (miR-34c) is highly correlated with organ fibrosis including pulmonary fibrosis. In this study, we found that miR-34c-5p could alleviate the occurrence and development of silica-mediated EMT. Fos-related antigen 1 was identified as a functional target of miR-34c-5p by bioinformatics analysis and the dual luciferase gene reporting assay. Importantly, chemically induced up-regulation of hsa-miR-34c-5p correlated inversely with the expression of Fra-1 and further exploration found that the miR-34c-5p/Fra-1 axis inhibits the activation of the phosphatase and tensin homolog deleted on chromosome 10/phosphatidylinositol-4,5-bisphosphate3-kinase/protein kinase B (PTEN/PI3K/AKT) signaling pathway. In addition, through interaction with PTEN/p53 it inhibits the proliferation and migration of human bronchial epithelial cells stimulated by silica, and promotes cell apoptosis, thereby preventing EMT. This finding provides a promising biomarker for the diagnosis and prognosis of pulmonary fibrosis. Furthermore, overexpression of miR-34c-5p represents a potential therapeutic approach.
Assuntos
MicroRNAs , Fibrose Pulmonar , Proliferação de Células/genética , Poeira , Transição Epitelial-Mesenquimal/genética , Fibrose , Humanos , MicroRNAs/genética , MicroRNAs/metabolismo , PTEN Fosfo-Hidrolase/genética , PTEN Fosfo-Hidrolase/metabolismo , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Proto-Oncogênicas c-akt/genética , Proteínas Proto-Oncogênicas c-akt/metabolismo , Proteínas Proto-Oncogênicas c-fos , Fibrose Pulmonar/induzido quimicamente , Fibrose Pulmonar/genética , Transdução de Sinais/genética , Dióxido de Silício/toxicidade , Proteína Supressora de Tumor p53/metabolismoRESUMO
Ataxia oculomotor apraxia type 2 (AOA2) is a rare autosomal recessive cerebellar ataxia. Recent evidence suggests that the protein defective in this syndrome, senataxin (SETX), functions in RNA processing to protect the integrity of the genome. To date, only patient-derived lymphoblastoid cells, fibroblasts and SETX knockdown cells were available to investigate AOA2. Recent disruption of the Setx gene in mice did not lead to neurobehavioral defects or neurodegeneration, making it difficult to study the etiology of AOA2. To develop a more relevant neuronal model to study neurodegeneration in AOA2, we derived neural progenitors from a patient with AOA2 and a control by induced pluripotent stem cell (iPSC) reprogramming of fibroblasts. AOA2 iPSC and neural progenitors exhibit increased levels of oxidative damage, DNA double-strand breaks, increased DNA damage-induced cell death and R-loop accumulation. Genome-wide expression and weighted gene co-expression network analysis in these neural progenitors identified both previously reported and novel affected genes and cellular pathways associated with senataxin dysfunction and the pathophysiology of AOA2, providing further insight into the role of senataxin in regulating gene expression on a genome-wide scale. These data show that iPSCs can be generated from patients with the autosomal recessive ataxia, AOA2, differentiated into neurons, and that both cell types recapitulate the AOA2 cellular phenotype. This represents a novel and appropriate model system to investigate neurodegeneration in this syndrome.
Assuntos
Reprogramação Celular , Modelos Animais de Doenças , Mutação , Células-Tronco Neurais/metabolismo , RNA Helicases/genética , Ataxias Espinocerebelares/congênito , Animais , Apoptose , Quebras de DNA de Cadeia Dupla , DNA Helicases , Feminino , Fibroblastos/fisiologia , Humanos , Células-Tronco Pluripotentes Induzidas/fisiologia , Camundongos , Enzimas Multifuncionais , Neurônios/fisiologia , Estresse Oxidativo , Ataxias Espinocerebelares/genética , Ataxias Espinocerebelares/metabolismo , Ataxias Espinocerebelares/fisiopatologiaRESUMO
Senataxin, mutated in the human genetic disorder ataxia with oculomotor apraxia type 2 (AOA2), plays an important role in maintaining genome integrity by coordination of transcription, DNA replication, and the DNA damage response. We demonstrate that senataxin is essential for spermatogenesis and that it functions at two stages in meiosis during crossing-over in homologous recombination and in meiotic sex chromosome inactivation (MSCI). Disruption of the Setx gene caused persistence of DNA double-strand breaks, a defect in disassembly of Rad51 filaments, accumulation of DNA:RNA hybrids (R-loops), and ultimately a failure of crossing-over. Senataxin localised to the XY body in a Brca1-dependent manner, and in its absence there was incomplete localisation of DNA damage response proteins to the XY chromosomes and ATR was retained on the axial elements of these chromosomes, failing to diffuse out into chromatin. Furthermore persistence of RNA polymerase II activity, altered ubH2A distribution, and abnormal XY-linked gene expression in Setxâ»/â» revealed an essential role for senataxin in MSCI. These data support key roles for senataxin in coordinating meiotic crossing-over with transcription and in gene silencing to protect the integrity of the genome.
Assuntos
Dano ao DNA/genética , DNA Helicases/genética , Recombinação Homóloga/genética , Meiose/genética , Espermatogênese , Animais , Apraxias/congênito , Ataxia/genética , Cromatina/genética , Síndrome de Cogan/genética , Troca Genética , Quebras de DNA de Cadeia Dupla , Reparo do DNA/genética , Replicação do DNA/genética , Inativação Gênica , Humanos , Masculino , Camundongos , Enzimas Multifuncionais , RNA Helicases/genética , RNA Helicases/metabolismo , Rad51 Recombinase/metabolismo , Inativação do Cromossomo X/genéticaAssuntos
Proteínas Mutadas de Ataxia Telangiectasia/metabolismo , Ataxia Telangiectasia/metabolismo , Estresse Oxidativo , Mucosa Respiratória/metabolismo , Infecções Respiratórias/metabolismo , Infecções Estreptocócicas/metabolismo , Ataxia Telangiectasia/genética , Proteínas Mutadas de Ataxia Telangiectasia/genética , Estudos de Casos e Controles , Células Cultivadas , Humanos , Mucosa Nasal/metabolismo , Streptococcus pneumoniaeRESUMO
Epidemiological evidence links lower air quality with increased incidence and severity of COVID-19; however, mechanistic data have yet to be published. We hypothesized air pollution-induced oxidative stress in the nasal epithelium increased viral replication and inflammation. Nasal epithelial cells (NECs), collected from healthy adults, were grown into a fully differentiated epithelium. NECs were infected with the ancestral strain of SARS-CoV-2. An oxidant combustion by-product found in air pollution, the environmentally persistent free radical (EPFR) DCB230, was used to mimic pollution exposure four hours prior to infection. Some wells were pretreated with antioxidant, astaxanthin, for 24 hours prior to EPFR-DCB230 exposure and/or SARS-CoV-2 infection. Outcomes included viral replication, epithelial integrity, surface receptor expression (ACE2, TMPRSS2), cytokine mRNA expression (TNF-α, IFN-ß), intracellular signaling pathways, and oxidative defense enzymes. SARS-CoV-2 infection induced a mild phenotype in NECs, with some cell death, upregulation of the antiviral cytokine IFN-ß, but had little effect on intracellular pathways or oxidative defense enzymes. Prior exposure to EPFR-DCB230 increased SARS-CoV-2 replication, upregulated TMPRSS2 expression, increased secretion of the proinflammatory cytokine TNF-α, inhibited expression of the mucus producing MUC5AC gene, upregulated expression of p21 (apoptosis pathway), PINK1 (mitophagy pathway), and reduced levels of antioxidant enzymes. Pretreatment with astaxanthin reduced SARS-CoV-2 replication, downregulated ACE2 expression, and prevented most, but not all EPFR-DCB230 effects. Our data suggest that oxidant damage to the respiratory epithelium may underly the link between poor air quality and increased COVID-19. The apparent protection by antioxidants warrants further research.
Assuntos
COVID-19 , SARS-CoV-2 , Humanos , SARS-CoV-2/metabolismo , COVID-19/metabolismo , Antioxidantes/metabolismo , Fator de Necrose Tumoral alfa/metabolismo , Enzima de Conversão de Angiotensina 2/metabolismo , Radicais Livres/metabolismo , Citocinas/metabolismo , Mucosa Respiratória/metabolismo , Oxidantes/metabolismoRESUMO
Oxidative stress (OS) in the airway epithelium is associated with cell damage, inflammation, and mitochondrial dysfunction that may initiate or worsen respiratory disease. However, it is unclear whether exogenous antioxidants can provide protection to the airway epithelium from OS. Resveratrol and astaxanthin are nutritional compounds that have shown diverse benefits including protection against OS and inflammation in various situations. The aim of this study was to examine the utility of pre-treatment with resveratrol and astaxanthin to prevent the negative effects of oxidant exposure and restore redox homeostasis in a well-differentiated epithelium grown from primary human nasal epithelial cells (NECs) at the air-liquid interface. Fully differentiated NECs were pretreated with the antioxidants for 24 hours and the cultured epithelia was subsequently exposed to hydrogen peroxide (H2O2) for 1 hour to induce an acute OS. Responses measured included mitochondrial reactive oxygen species (mtROS) generation, redox status (GSH/GSSG ratio), cellular ATP, and signaling pathways (SIRT1, FOXO3, p21, PINK1, PARKIN, NRF2). Following H2O2 exposure, mtROS production increased by 4-fold compared with control (p<0.01) and pre-treatment with resveratrol or astaxanthin reduced this by 50% (p<0.05). H2O2 exposure reduced GSH/GSSG ratio and this decline was prevented by antioxidants pre-treatment. H2O2 exposure caused 2.5-fold increase in p21 mRNA expression compared with control (p<0.05), while a slight decrease in p21 mRNA expression was observed when cells were pre-treated with resveratrol or astaxanthin. Our results demonstrate that antioxidants, resveratrol, and astaxanthin were able to protect cells from an acute OS. These agents show promise that encourages further research.
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Oxidative stress (OS) in the airway epithelium is associated with inflammation, cell damage, and mitochondrial dysfunction that may initiate or worsen respiratory disease. Redox regulation maintains the equilibrium of pro-oxidant/antioxidant reactions but can be disturbed by environmental exposures. The mechanism(s) underlying the induction and impact of OS on airway epithelium and how these influences on respiratory disease is poorly understood. The aim of this study was to develop a stress response model in primary human nasal epithelial cells (NECs) grown at the air-liquid interface (ALI) into a well-differentiated epithelium and to use this model to investigate the mechanisms underlying OS. Hydrogen peroxide (H2O2) was used to induce acute OS and the responses were measured with trans epithelial electrical resistance (TEER), membrane permeability, cell death (LDH release), mitochondrial reactive oxygen species (mtROS) generation, redox status (GSH/GSSG ratio), cellular ATP, and signaling pathways (SIRT1, FOXO3, p53, p21, PINK1, PARKIN, NRF2). Following 25 mM (sensitive) or 50mM (resistant) H2O2 exposure, cell integrity decreased (p<0.05), GSH/GSSG ratio reduced (p<0.05), and ATP production declined by 83% (p<0.05) in the sensitive and 55% (p<0.05) in the resistant group; mtROS production increased 3.4-fold (p<0.001). Significant inter-individual differences between healthy humans with regards to susceptibility to OS, and differential activation of various pathways (FOXO3, PARKIN) were observed. These intra-individual differences in susceptibility to OS may be attributed to resistant individuals having more mitochondria or greater mitochondrial function.
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The blood-brain barrier (BBB) is a selective, semi-permeable layer of endothelial cells that protects the central nervous system from harmful substances circulating in blood. It is one of the important barriers of the nervous system. BBB dysfunction is an early pathophysiological change observed in nervous system diseases. There are few treatments for BBB dysfunction, so this motivates the review. Ferroptosis is a novel cell death mode caused by iron-mediated lipid peroxidation accumulation, which has recently attracted more attention due to its possible role in nervous system disorders. Studies have shown that lipid peroxidation and iron accumulation are related to the barrier dysfunction, especially the expression of tight junction proteins. Therefore, examination of the relationship between ferroptosis and BBB dysfunction may reveal new targets for the treatment of brain diseases.
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Mutations in genes that function in nucleic metabolism have been shown to be linked to Aicardi-Goutières syndrome. In this issue of Neuron, Aditi et al. (2021) provide evidence that DNA damage-dependent signaling rather than type I interferon signaling underlies neurodegeneration in this class of neurodevelopmental/neuroinflammatory disease.
Assuntos
Doenças Autoimunes do Sistema Nervoso , Malformações do Sistema Nervoso , Doenças Autoimunes do Sistema Nervoso/genética , Doenças Autoimunes do Sistema Nervoso/fisiopatologia , Dano ao DNA , Humanos , Mutação , Malformações do Sistema Nervoso/genéticaRESUMO
Oxidative stress and the inflammatory response are two important mechanisms of silica-induced lung injury. Hesperetin (HSP) is a natural flavonoid compound that is found in citrus fruits and has been indicated to exhibit strong antioxidant and anti-inflammatory properties. The current study evaluated the protective effect of HSP on lung injury in rats exposed to silica. The results indicated that the degree of alveolitis and pulmonary fibrosis in the HSP-treated group was significantly decreased compared with the silica model group. The content of hydroxyproline (HYP) was also revealed to decrease overall in the HSP treated group compared with the silica model group, indicating that the degree of pulmonary fibrosis was decreased compared with the silica model group. The present study also demonstrated that HSP reduced oxidation levels of malondialdehyde (MDA) and increased the activities of antioxidant enzymes superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-PX). Total antioxidant capacity (T-AOC) was also increased following HSP treatment, indicating that HSP can alleviate oxidative stress in the lung tissue of silica-exposed rats. In addition, HSP was revealed to inhibit the synthesis and secretion of fibrogenic factor TGF-ß1, reduce the production of pro-inflammatory cytokines IL-1ß, IL-4, TNF-α and increase the levels of anti-inflammatory factors IFN-γ and IL-10. The current study demonstrated that HSP can effectively attenuate silica-induced lung injury by reducing oxidative damage and the inflammatory response.
RESUMO
Long-term exposure to crystalline silica particles leads to silicosis characterized by persistent inflammation and progressive fibrosis in the lung. So far, there is no specific treatment to cure the disease other than supportive care. In this study, we examined the effects of metformin, a prescribed drug for type || diabetes on silicosis and explored the possible mechanisms in an established rat silicosis model in vivo, and an in vitro co-cultured model containing human macrophages cells (THP-1) and human bronchial epithelial cells (HBEC). Our results showed that metformin significantly alleviated the inflammation and fibrosis of lung tissues of rats exposed to silica particles. Metformin significantly reduced silica particle-induced inflammatory cytokines including transforming growth factor-ß1 (TGF-ß1), tumor necrosis factor-α (TNF-α) and interleukin-1ß (IL-1ß) in rat lung tissue and HBEC culture supernatant. The protein levels of Vimentin and α-smooth muscle actin (α-SMA) were significantly decreased by metfomin while expression level of E-cadherin (E-Cad) increased. Besides, metformin increased the expression levels of phosphorylated adenosine 5'-monophosphate (AMP)-activated protein kinase (p-AMPK), microtubule-associated protein (MAP) light chain 3B (LC3B) and Beclin1 proteins, and reduced levels of phosphorylated mammalian target of rapamycin (p-mTOR) and p62 proteins in vivo and in vitro. These results suggest that metformin could inhibit silica-induced pulmonary fibrosis by activating autophagy through the AMPK-mTOR pathway.
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There is evidence that ATM mutated in ataxia-telangiectasia (A-T) plays a key role in protecting against mitochondrial dysfunction, the mechanism for which remains unresolved. We demonstrate here that ATM-deficient cells are exquisitely sensitive to nutrient deprivation, which can be explained by defective cross talk between the endoplasmic reticulum (ER) and the mitochondrion. Tethering between these two organelles in response to stress was reduced in cells lacking ATM, and consistent with this, Ca2+ release and transfer between ER and mitochondria was reduced dramatically when compared with control cells. The impact of this on mitochondrial function was evident from an increase in oxygen consumption rates and a defect in mitophagy in ATM-deficient cells. Our findings reveal that ER-mitochondrial connectivity through IP3R1-GRP75-VDAC1, to maintain Ca2+ homeostasis, as well as an abnormality in mitochondrial fusion defective in response to nutrient stress, can account for at least part of the mitochondrial dysfunction observed in A-T cells.
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Silicosis is a fatal pulmonary disease caused by the inhalation of silica dust, and characterized by inflammation and fibrosis of the lung, with no effective treatment to date. Here we investigate the effect of emodin, an anthraquinone derivative isolated from rhubarb using a mouse silicosis model and in vitro cultured human macrophages and alveolar epithelial cells. Results from histological examination indicated that emodin reduced the degree of alveolitis and fibrosis in the lungs of mice exposed to silica particles. We also demonstrated that emodin effectively inhibited the phosphorylation of Smad3 and NF-κB and reduced the levels of inflammatory factors in the lung tissue of mice treated with silica particles. In addition, we found that emodin inhibited apoptosis and demonstrated an anti-fibrotic effect by down-regulating the pro-apoptotic protein Bax and up-regulating the anti-apoptotic protein Bcl-2. Furthermore, emodin increased E-cadherin levels, reduced the expression of Vimentin, α-SMA and Col-I, as well as pro-inflammatory factors TGF-ß1, TNF-α and IL-1ß in vivo and in vitro. These results suggested that emodin can regulate epithelial-mesenchymal transition (EMT) through the inhibition of the TGF-ß1/Smad3 signaling pathway and the NF-κB signaling pathway to prevent alveolar inflammation and apoptotic process. Overall, this study showed that emodin can alleviate pulmonary fibrosis in silicosis through regulating the inflammatory response and fibrotic process at multiple levels.
Assuntos
Lesão Pulmonar Aguda/prevenção & controle , Apoptose/efeitos dos fármacos , Emodina/farmacologia , Transição Epitelial-Mesenquimal/efeitos dos fármacos , Pneumonia/prevenção & controle , Alvéolos Pulmonares/efeitos dos fármacos , Fibrose Pulmonar/prevenção & controle , Silicose/prevenção & controle , Células A549 , Lesão Pulmonar Aguda/induzido quimicamente , Lesão Pulmonar Aguda/metabolismo , Lesão Pulmonar Aguda/patologia , Animais , Anti-Inflamatórios/metabolismo , Proteínas Reguladoras de Apoptose/metabolismo , Técnicas de Cocultura , Modelos Animais de Doenças , Humanos , Macrófagos/efeitos dos fármacos , Macrófagos/metabolismo , Masculino , Camundongos Endogâmicos C57BL , Pneumonia/induzido quimicamente , Pneumonia/metabolismo , Pneumonia/patologia , Alvéolos Pulmonares/metabolismo , Alvéolos Pulmonares/patologia , Fibrose Pulmonar/induzido quimicamente , Fibrose Pulmonar/metabolismo , Fibrose Pulmonar/patologia , Transdução de Sinais , Dióxido de Silício , Silicose/metabolismo , Silicose/patologia , Células THP-1RESUMO
The protein defective in the human genetic disorder ataxia-telangiectasia, ATM, plays a central role in responding to DNA double strand breaks and other lesions to protect the genome against DNA damage and in this way minimize the risk of mutations that can lead to abnormal cellular behaviour. Its function in normal cells is to protect the cell against genotoxic stress but inadvertently it can assist cancer cells by providing resistance against chemotherapeutic agents and thus favouring tumour growth and survival. However, it is now evident that ATM also functions in a DNA damage-independent fashion to protect the cell against other forms of stress such as oxidative and nutrient stress and this non-canonical mechanism may also be relevant to cancer susceptibility in individuals who lack a functional ATM gene. Thus the use of ATM inhibitors to combat resistance in tumours may extend beyond a role for this protein in the DNA damage response. Here, we provide some background on ATM and its activation and investigate the efficacy of ATM inhibitors in treating cancer.
Assuntos
Antineoplásicos/uso terapêutico , Proteínas Mutadas de Ataxia Telangiectasia/antagonistas & inibidores , Dano ao DNA , Reparo do DNA , Terapia de Alvo Molecular , Neoplasias/tratamento farmacológico , Animais , Humanos , Mutação , Neoplasias/genética , Neoplasias/patologia , FosforilaçãoRESUMO
An amendment to this paper has been published and can be accessed via a link at the top of the paper.
RESUMO
Respiratory disease is a major cause of morbidity and mortality in patients with ataxia-telangiectasia (A-T) who are prone to recurrent sinopulmonary infections, bronchiectasis, pulmonary fibrosis, and pulmonary failure. Upper airway infections are common in patients and S. pneumoniae is associated with these infections. We demonstrate here that the upper airway microbiome in patients with A-T is different from that to healthy controls, with S. pneumoniae detected largely in patients only. Patient-specific airway epithelial cells and differentiated air-liquid interface cultures derived from these were hypersensitive to infection which was at least in part due to oxidative damage since it was partially reversed by catalase. We also observed increased levels of the pro-inflammatory cytokines IL-8 and TNF-α (inflammasome-independent) and a decreased level of the inflammasome-dependent cytokine IL-ß in patient cells. Further investigation revealed that the ASC-Caspase 1 signalling pathway was defective in A-T airway epithelial cells. These data suggest that the heightened susceptibility of these cells to S. pneumoniae infection is due to both increased oxidative damage and a defect in inflammasome activation, and has implications for lung disease in these patients.
Assuntos
Ataxia Telangiectasia/patologia , Células Epiteliais/patologia , Imunidade Inata , Pulmão/patologia , Estresse Oxidativo , Infecções Pneumocócicas/imunologia , Infecções Pneumocócicas/patologia , Streptococcus pneumoniae/fisiologia , Adolescente , Proteínas Mutadas de Ataxia Telangiectasia/metabolismo , Estudos de Casos e Controles , Diferenciação Celular , Células Cultivadas , Criança , Pré-Escolar , Células Epiteliais/imunologia , Células Epiteliais/microbiologia , Feminino , Humanos , Inflamassomos/metabolismo , Inflamação/patologia , Pulmão/microbiologia , Masculino , Nariz/patologiaRESUMO
Previous studies have demonstrated that bone marrow mesenchymal stem cell (BMSC) transplantation is a promising treatment strategy for pulmonary fibrosis. Although encouraging results have been obtained using animal models of bleomycin (BLM)-induced pulmonary fibrosis, it is evident that transplantation of BMSCs at various time-points after BLM administration has produced different results in terms of treatment efficacy. To shed light on the potential utility of BMSCs for the treatment of lung disease, the present study performed a meta-analysis to estimate the efficacy of BMSCs in animal models of BLM-induced pulmonary fibrosis, and compare early transplantation (BMSCs injected on the same day after administration of BLM) with late transplantation (BMSCs injected on the 14th day after administration of BLM). Relevant studies were retrieved from the MEDLINE, PubMed, Chinese Knowledge Infrastructure and WanFang databases using a comprehensive search approach. A total of 6 studies involving 228 model rats were included. Meta-analysis indicated that early BMSC transplantation was able to prevent or reduce BLM-induced alveolitis and pulmonary fibrosis, while late BMSC transplantation was able to reduce alveolitis, but there was no significant evidence regarding improvement of pulmonary fibrosis. Although BMSC therapy was identified to be generally beneficial in rodent models of BLM-induced pulmonary fibrosis, the efficacy of early transplantation appears to be more satisfactory; overall, the efficacy of transplantation of BMSCs at the acute inflammatory phase was more effective compared with that at the chronic fibrosis stage. Of note, regarding alveolitis and pulmonary fibrosis scores after late transplantation of BMSCs, the sensitivity analysis revealed that the scores were less stable; thus, this result must be interpreted with caution. Furthermore, the quality and methodology of the included studies was comparatively low. Therefore, higher-quality and more rigorous studies are required to validate the results of the present meta-analysis in the future.
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Toluene-diisocyanate (TDI) is mainly used in the manufacturing process of polyurethane foams, and is a potent inducer of occupational asthma characterized by airway inflammation and airway hyperreactivity. Thymic stromal lymphopoietin (TSLP) plays an important role in the development of asthma, and correlating with the differentiation of Th2 and Th17 cells. However, the role of TSLP in TDI-induced asthma remains unclear. In this study, 96 TDI-exposed workers as well as a mouse model of TDI-induced asthma were investigated. The air exposure assessment result of TDI in the workplace showed that workers were exposed to inhalation of a very high concentration of TDI, approximately 8 times the recommended level, leading to a decrease in pulmonary function and an increase in inflammatory cells, as well as TSLP and IgE levels in the supernatant of sputum obtained from exposed workers. In order to further investigate the role of TSLP in the pathogenesis of TDI-induced asthma, a mouse model of TDI-induced asthma was also employed. Histopathological analysis of mouse lung and bronchus showed an obvious infiltration of inflammatory cells around the bronchus. The levels of inflammatory cells, IFN-γ, IL-4 and IL-17 in bronchoalveolar lavage fluid (BALF), the expression levels of TSLP protein and ROR-γt and IL-17 mRNA in mouse lung tissues were also significantly increased. However, after treatment with TSLP neutralizing antibody (TSLP-Ab), the degree of pulmonary and bronchial inflammation in mice was significantly alleviated, and the levels of inflammatory cells, IFN-γ, IL-4 and IL-17 in BALF, and the expression levels of ROR-γt and IL-17 mRNA in lung tissue were significantly decreased. Our data shows that TSLP plays an important role in the pathogenesis of TDI-induced asthma, and that TSLP-Ab can effectively alleviate TDI-induced airway inflammation of asthma.