RESUMO
Barrett's esophagus is an intestine-like metaplasia and precursor of esophageal adenocarcinoma. Triggered by gastroesophageal reflux disease, the origin of this metaplasia remains unknown. p63-deficient mice, which lack squamous epithelia, may model acid-reflux damage. We show here that p63 null embryos rapidly develop intestine-like metaplasia with gene expression profiles similar to Barrett's metaplasia. We track its source to a unique embryonic epithelium that is normally undermined and replaced by p63-expressing cells. Significantly, we show that a discrete population of these embryonic cells persists in adult mice and humans at the squamocolumnar junction, the source of Barrett's metaplasia. We show that upon programmed damage to the squamous epithelium, these embryonic cells migrate toward adjacent, specialized squamous cells in a process that may recapitulate early Barrett's. Our findings suggest that certain precancerous lesions, such as Barrett's, initiate not from genetic alterations but from competitive interactions between cell lineages driven by opportunity.
Assuntos
Esôfago de Barrett/patologia , Esôfago/patologia , Animais , Esôfago de Barrett/embriologia , Perfilação da Expressão Gênica , Humanos , Intestino Delgado/citologia , Metaplasia , Camundongos , Fosfoproteínas/genética , Fosfoproteínas/metabolismo , Transativadores/genética , Transativadores/metabolismoRESUMO
The extent of lung regeneration following catastrophic damage and the potential role of adult stem cells in such a process remains obscure. Sublethal infection of mice with an H1N1 influenza virus related to that of the 1918 pandemic triggers massive airway damage followed by apparent regeneration. We show here that p63-expressing stem cells in the bronchiolar epithelium undergo rapid proliferation after infection and radiate to interbronchiolar regions of alveolar ablation. Once there, these cells assemble into discrete, Krt5+ pods and initiate expression of markers typical of alveoli. Gene expression profiles of these pods suggest that they are intermediates in the reconstitution of the alveolar-capillary network eradicated by viral infection. The dynamics of this p63-expressing stem cell in lung regeneration mirrors our parallel finding that defined pedigrees of human distal airway stem cells assemble alveoli-like structures in vitro and suggests new therapeutic avenues to acute and chronic airway disease.
Assuntos
Brônquios/citologia , Vírus da Influenza A Subtipo H1N1 , Influenza Humana/patologia , Pulmão/fisiologia , Alvéolos Pulmonares/citologia , Síndrome do Desconforto Respiratório/patologia , Células-Tronco/citologia , Animais , Modelos Animais de Doenças , Perfilação da Expressão Gênica , Humanos , Pulmão/citologia , Pulmão/virologia , Camundongos , Camundongos Endogâmicos C57BL , Alvéolos Pulmonares/virologia , Ratos , Fatores de Transcrição/genética , CicatrizaçãoRESUMO
Chronic inflammation and dysregulated repair mechanisms after epithelial damage have been implicated in chronic obstructive pulmonary disease (COPD). However, the lack of ex vivo-models that accurately reflect multicellular lung tissue hinders our understanding of epithelial-mesenchymal interactions in COPD. Through a combination of transcriptomic and proteomic approaches applied to a sophisticated in vitro iPSC-alveolosphere with fibroblasts model, epithelial-mesenchymal crosstalk was explored in COPD and following SARS-CoV-2 infection. These experiments profiled dynamic changes at single-cell level of the SARS-CoV-2-infected alveolar niche that unveiled the complexity of aberrant inflammatory responses, mitochondrial dysfunction, and cell death in COPD, which provides deeper insights into the accentuated tissue damage/inflammation/remodeling observed in patients with SARS-CoV-2 infection. Importantly, this 3D system allowed for the evaluation of ACE2-neutralizing antibodies and confirmed the potency of this therapy to prevent SARS-CoV-2 infection in the alveolar niche. Thus, iPSC-alveolosphere cultured with fibroblasts provides a promising model to investigate disease-specific mechanisms and to develop novel therapeutics.
Assuntos
COVID-19 , Células-Tronco Pluripotentes Induzidas , Doença Pulmonar Obstrutiva Crônica , Humanos , SARS-CoV-2 , Proteômica , Imunoterapia , InflamaçãoRESUMO
BACKGROUND: Benralizumab is a humanised, anti-interleukin-5 receptor α monoclonal antibody with anti-eosinophilic activity. Lack of fucose (afucosylation) increases its affinity to CD16a and significantly enhances antibody-dependent cell-mediated cytotoxicity by natural killer (NK) cells. Although benralizumab proved clinically efficacious in clinical trials for patients with severe asthma and hypereosinophilic syndrome, in-depth characterisation of its anti-eosinophilic mechanisms of action remains elusive. METHODS: Here, we further investigated the mechanisms involved in benralizumab's anti-eosinophilic activities by employing relevant primary human autologous cell co-cultures and real-time-lapse imaging combined with flow cytometry. RESULTS: In the presence of NK cells, benralizumab induced potent eosinophil apoptosis as demonstrated by the upstream induction of Caspase-3/7 and upregulation of cytochrome c. In addition, we uncovered a previously unrecognised mechanism whereby benralizumab can induce eosinophil phagocytosis/efferocytosis by macrophages, a process called antibody-dependent cellular phagocytosis. Using live cell imaging, we unravelled the stepwise processes leading to eosinophil apoptosis and uptake by activated macrophages. Through careful observations of cellular co-culture assays, we identified a novel role for macrophage-derived tumour necrosis factor (TNF) to further enhance benralizumab-mediated eosinophil apoptosis through activation of TNF receptor 1 on eosinophils. TNF-induced eosinophil apoptosis was associated with cytochrome c upregulation, mitochondrial membrane depolarisation and increased Caspase-3/7 activity. Moreover, activated NK cells were found to amplify this axis through the secretion of interferon-γ, subsequently driving TNF expression by macrophages. CONCLUSIONS: Our data provide deeper insights into the timely appearance of events leading to benralizumab-induced eosinophil apoptosis and suggest that additional mechanisms may contribute to the potent anti-eosinophilic activity of benralizumab in vivo. Importantly, afucosylation of benralizumab strongly enhanced its potency for all mechanisms investigated.
Assuntos
Antiasmáticos , Asma , Antiasmáticos/farmacologia , Antiasmáticos/uso terapêutico , Anticorpos Monoclonais Humanizados/farmacologia , Anticorpos Monoclonais Humanizados/uso terapêutico , Eosinófilos , HumanosRESUMO
The prominent role of Ca(2+) in cell physiology is mediated by a whole set of proteins involved in Ca(2+)-signal generation, deciphering and arrest. Among these intracellular proteins, calmodulin (CaM) known as a prototypical calcium sensor, serves as a ubiquitous carrier of the intracellular calcium signal in all eukaryotic cell types. CaM is assumed to be involved in many diseases including Parkinson, Alzheimer, and rheumatoid arthritis. Defects in some of many reaction partners of CaM might be responsible for disease symptoms. Several classes of drugs bind to CaM with unwanted side effects rather than specific therapeutic use. Thus, it may be more promising to concentrate at searching for pharmacological interferences with the CaM target proteins, in order to find tools for dissecting and investigating CaM-regulatory and modulatory functions in cells. In the present study, we have established a screening assay based on fluorescence polarization (FP) to identify a diverse set of small molecules that disrupt the regulatory function of CaM. The FP-based CaM assay consists in the competition of two fluorescent probes and a library of chemical compounds for binding to CaM. Screening of about 5300 compounds (Strasbourg Academic Library) by displacement of the probe yielded 39 compounds in a first step, from which 6 were selected. Those 6 compounds were characterized by means of calorimetry studies and by competitive displacement of two fluorescent probes interacting with CaM. Moreover, those small molecules were tested for their capability to displace 8 different CaM binding domains from CaM. Our results show that these CaM/small molecules interactions are not functionally equivalent. The strategy that has been set up for CaM is a general model for the development and validation of other CaM interactors, to decipher their mode of action, or rationally design more specific CaM antagonists. Moreover, this strategy may be used for other protein binding assays intended to screen for molecules with preferred binding activity. This article is part of a Special Issue entitled: 12th European Symposium on Calcium.
Assuntos
Cálcio/metabolismo , Calmodulina/antagonistas & inibidores , Calmodulina/metabolismo , Membrana Celular/metabolismo , Fragmentos de Peptídeos/farmacologia , Sítio Alostérico , Sítios de Ligação , Ligação Competitiva , Canais de Cálcio Tipo L/metabolismo , Polarização de Fluorescência , Humanos , Estrutura Molecular , Biblioteca de Peptídeos , Ligação Proteica , TermodinâmicaRESUMO
Calmodulin (CaM) is a ubiquitous Ca(2+) sensor regulating many biochemical processes in eukaryotic cells. Its interaction with a great variety of different target proteins has led to the fundamental question of its mechanism of action. CaM exhibits four "EF hand" type Ca(2+) binding sites. One way to explain CaM functioning is to consider that the protein interacts differently with its target proteins depending on the number of Ca(2+) ions bound to it. To test this hypothesis, the binding properties of three entities known to interact with CaM (a fluorescent probe and two peptide analogs to the CaM binding sites of death associated protein kinase (DAPK) and of EGFR) were investigated using a quantitative approach based on fluorescence polarization (FP). Probe and peptide interactions with CaM were studied using a titration matrix in which both CaM and calcium concentrations were varied. Experiments were performed with SynCaM, a hybrid CaM able to activate CaM dependent enzymes from mammalian and plant cells. Results show that the interaction between CaM and its targets is regulated by the number of calcium ions bound to the protein, namely one for the DAPK peptide, two for the probe and four for the EGFR peptide. The approach used provides a new tool to elaborate a typology of CaM-targets, based on their recognition by the various CaM-Ca(n) (n=0-4) complexes. This article is part of a Special Issue entitled: 11th European Symposium on Calcium.
Assuntos
Proteínas Reguladoras de Apoptose/química , Proteínas Reguladoras de Apoptose/metabolismo , Bioquímica/métodos , Proteínas Quinases Dependentes de Cálcio-Calmodulina/química , Proteínas Quinases Dependentes de Cálcio-Calmodulina/metabolismo , Cálcio/metabolismo , Calmodulina/metabolismo , Receptores ErbB/química , Receptores ErbB/metabolismo , Sequência de Aminoácidos , Proteínas Quinases Associadas com Morte Celular , Corantes Fluorescentes/metabolismo , Cinética , Dados de Sequência Molecular , Proteínas Mutantes/química , Proteínas Mutantes/metabolismo , Peptídeos/química , Peptídeos/metabolismo , Ligação Proteica , Estrutura Terciária de Proteína , Proteínas Recombinantes/química , Proteínas Recombinantes/metabolismo , Eletricidade Estática , TermodinâmicaRESUMO
OBJECTIVE: Novel biomarkers related to main clinical hallmarks of Chronic obstructive pulmonary disease (COPD), a heterogeneous disorder with pulmonary and extra-pulmonary manifestations, were investigated by profiling the serum levels of 1305 proteins using Slow Off-rate Modified Aptamers (SOMA)scan technology. METHODS: Serum samples were collected from 241 COPD subjects in the multicenter French Cohort of Bronchial obstruction and Asthma to measure the expression of 1305 proteins using SOMAscan proteomic platform. Clustering of the proteomics was applied to identify disease subtypes and their functional annotation and association with key clinical parameters were examined. Cluster findings were revalidated during a follow-up visit, and compared to those obtained in a group of 47 COPD patients included in the Melbourne Longitudinal COPD Cohort. RESULTS: Unsupervised clustering identified two clusters within COPD subjects at inclusion. Cluster 1 showed elevated levels of factors contributing to tissue injury, whereas Cluster 2 had higher expression of proteins associated with enhanced immunity and host defense, cell fate, remodeling and repair and altered metabolism/mitochondrial functions. Patients in Cluster 2 had a lower incidence of exacerbations, unscheduled medical visits and prevalence of emphysema and diabetes. These protein expression patterns were conserved during a follow-up second visit, and substanciated, by a large part, in a limited series of COPD patients. Further analyses identified a signature of 15 proteins that accurately differentiated the two COPD clusters at the 2 visits. CONCLUSIONS: This study provides insights into COPD heterogeneity and suggests that overexpression of factors involved in lung immunity/host defense, cell fate/repair/ remodelling and mitochondrial/metabolic activities contribute to better clinical outcomes. Hence, high throughput proteomic assay offers a powerful tool for identifying COPD endotypes and facilitating targeted therapies.
Assuntos
Proteômica , Doença Pulmonar Obstrutiva Crônica , HumanosRESUMO
Calcium (Ca2+) is a ubiquitous second messenger which promotes cell responses through transient changes in intracellular concentrations. The prominent role of Ca2+ in cell physiology is mediated by a whole set of proteins constituting a Ca2+-signalling toolkit involved in Ca2+-signal generation, deciphering and arrest. The different Ca2+-signalosomes deliver Ca2+-signals with spatial and temporal dynamics to control the function of specific cell types. Among the intracellular proteins involved in Ca2+-signal deciphering, calmodulin (CaM) plays a pivotal role in controlling Ca2+-homeostasis and downstream Ca2+-based signalling events. Due to its ubiquitous expression in eukaryotic cells and the variety of proteins it interacts with, CaM is central in Ca2+-signalling networks. For these reasons, it is expected that disrupting or modifying CaM interactions with its target proteins will affect Ca2+-homeostasis and cellular responses. The resulting calcium response will vary depending on which interactions between CaM and target proteins are altered by the molecules and on the specific Ca2+-toolkit expressed in a given cell, even in the resting state. In the present paper, the effect of six classical CaM interactors (W5, W7, W12, W13, bifonazole and calmidazolium) was studied on Ca2+-signalling in tumor initiating cells isolated from human glioblastoma (TG1) and tobacco cells (BY-2) using the fluorescent Ca2+-sensitive Indo-1 dye and aequorin, respectively. Various Ca2+-fingerprints were obtained depending both on the CaM interactor used and the cell type investigated. These data demonstrate that interaction between the antagonists and CaM results in a differential inhibition of CaM-dependent proteins involved in Ca2+-signal regulation. In addition, the distinct Ca2+-fingerprints in tobacco and human tumor initiating glioblastoma cells induced by a given CaM interactor highlight the specificity of the Ca2+-signalosome in eukaryotic cells.
Assuntos
Sinalização do Cálcio/fisiologia , Cálcio/metabolismo , Calmodulina/metabolismo , Células Eucarióticas/metabolismo , Anisotropia , Calmodulina/antagonistas & inibidores , Linhagem Celular , Inibidores Enzimáticos/química , Inibidores Enzimáticos/metabolismo , Humanos , Imidazóis/química , Imidazóis/metabolismo , Estrutura Molecular , Espectrometria de Fluorescência , Sulfonamidas/química , Sulfonamidas/metabolismo , NicotianaRESUMO
Evidence points to an indispensable function of macrophages in tissue regeneration, yet the underlying molecular mechanisms remain elusive. Here we demonstrate a protective function for the IL-33-ST2 axis in bronchial epithelial repair, and implicate ST2 in myeloid cell differentiation. ST2 deficiency in mice leads to reduced lung myeloid cell infiltration, abnormal alternatively activated macrophage (AAM) function, and impaired epithelial repair post naphthalene-induced injury. Reconstitution of wild type (WT) AAMs to ST2-deficient mice completely restores bronchial re-epithelialization. Central to this mechanism is the direct effect of IL-33-ST2 signaling on monocyte/macrophage differentiation, self-renewal and repairing ability, as evidenced by the downregulation of key pathways regulating myeloid cell cycle, maturation and regenerative function of the epithelial niche in ST2-/- mice. Thus, the IL-33-ST2 axis controls epithelial niche regeneration by activating a large multi-cellular circuit, including monocyte differentiation into competent repairing AAMs, as well as group-2 innate lymphoid cell (ILC2)-mediated AAM activation.
Assuntos
Bronquíolos/metabolismo , Diferenciação Celular/efeitos dos fármacos , Células Epiteliais/metabolismo , Proteína 1 Semelhante a Receptor de Interleucina-1/metabolismo , Interleucina-33/metabolismo , Interleucina-33/farmacologia , Animais , Bronquíolos/lesões , Bronquíolos/patologia , Citocinas/metabolismo , Modelos Animais de Doenças , Células Epiteliais/patologia , Feminino , Proteína 1 Semelhante a Receptor de Interleucina-1/genética , Pulmão/patologia , Ativação Linfocitária , Linfócitos/metabolismo , Macrófagos/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Transdução de SinaisRESUMO
Periplakin is a component of the desmosomes that acts as a cytolinker between intermediate filament scaffolding and the desmosomal plaque. Periplakin is strongly expressed by epithelial cells in the lung and is a target antigen for autoimmunity in idiopathic pulmonary fibrosis. The aim of this study was to determine the role of periplakin during lung injury and remodeling in a mouse model of lung fibrosis induced by bleomycin. We found that periplakin expression was downregulated in the whole lung and in alveolar epithelial cells following bleomycin-induced injury. Deletion of the Ppl gene in mice improved survival and reduced lung fibrosis development after bleomycin-induced injury. Notably, Ppl deletion promoted an antiinflammatory alveolar environment linked to profound changes in type 2 alveolar epithelial cells, including overexpression of antiinflammatory cytokines, decreased expression of profibrotic mediators, and altered cell signaling with a reduced response to TGF-ß1. These results identify periplakin as a previously unidentified regulator of the response to injury in the lung.
Assuntos
Células Epiteliais Alveolares/patologia , Fibrose Pulmonar Idiopática/patologia , Lesão Pulmonar/patologia , Plaquinas/metabolismo , Mucosa Respiratória/patologia , Células Epiteliais Alveolares/efeitos dos fármacos , Células Epiteliais Alveolares/imunologia , Animais , Bleomicina/administração & dosagem , Bleomicina/toxicidade , Citocinas/imunologia , Citocinas/metabolismo , Modelos Animais de Doenças , Regulação para Baixo , Humanos , Fibrose Pulmonar Idiopática/induzido quimicamente , Fibrose Pulmonar Idiopática/imunologia , Lesão Pulmonar/induzido quimicamente , Lesão Pulmonar/imunologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Plaquinas/genética , Mucosa Respiratória/citologia , Mucosa Respiratória/efeitos dos fármacos , Mucosa Respiratória/imunologia , Transdução de Sinais/imunologiaRESUMO
In order to develop a fluorescence polarization (FP) assay for calcium binding proteins, a fluorescent peptides based library of 1328 compounds has been synthesized. The use of this library has been validated by setting up a FP-high-throughput screening (FP-HTS) assay for calmodulin using the synthetic gene product (synCaM). With this assay, a set of 880 FDA approved compounds was screened. Besides the promazine class, we discovered two new classes of compounds that interact with calmodulin in a calcium dependent manner. One class has compounds with anti-histaminic/spasmolytic activities, and the other one are detergents with antibacterial activities.
Assuntos
Proteínas de Ligação ao Cálcio/química , Calmodulina/química , Avaliação Pré-Clínica de Medicamentos/métodos , Polarização de Fluorescência/métodos , Biblioteca de Peptídeos , Proteínas de Ligação ao Cálcio/genética , Calmodulina/genética , Ligantes , Peptídeos/síntese química , Peptídeos/químicaRESUMO
Understanding the role of calmodulin (CaM) in calcium signal transduction implies to describe the -calcium-dependent molecular mechanism of interaction of CaM with the various CaM-binding domains (CBD). In order to fulfill this aim, we have developed a new strategy and the afferent techniques to quantify the interaction of CaM with any CBD as a function of calcium concentration. Excel software has been used to deconvolute the experimental data and to obtain the macroscopic constants characterizing the system. We are illustrating our approach on six different CaM/CBD. This strategy may be used to analyze the interaction between any calcium-binding protein and its targets.
Assuntos
Calmodulina/química , Calmodulina/metabolismo , Sequência de Aminoácidos , Soluções Tampão , Polarização de Fluorescência , Humanos , Modelos Moleculares , Dados de Sequência Molecular , Peptídeos/síntese química , Peptídeos/química , Peptídeos/metabolismo , Ligação Proteica , Estrutura Terciária de ProteínaRESUMO
Two novel solid-phase organic tagging (SPOrT) resins were synthesized to facilitate the labeling of peptides and small organic compounds with a fluorescent probe. Both resins were obtained from the commercially available backbone amide linker (BAL) resin. Following the solid-phase synthesis of model compounds, a tripeptide and benzazepine, the fluorescent probe derived from Lissamine Rhodamine B was incorporated through CuI-catalyzed 1,3-dipolar cycloaddition. Final cleavage in acidic media enabled access to both types of molecules in good yield with high purity. The SPOrT resin was successfully applied to the preparation of the first non-peptidic fluorescent compound with a nanomolar affinity for the human vasopressin V2 receptor (V2R) subtype. This molecule will find application in binding assays that use polarization or fluorescence resonance energy-transfer (FRET) techniques. The SPOrT resins are also well suited for other tags and the parallel synthesis of a fluorescently tagged library for protein screening.
Assuntos
Corantes Fluorescentes/síntese química , Peptídeos/química , Receptores de Vasopressinas/química , Eletroquímica , Corantes Fluorescentes/química , Ligantes , Lítio/química , Receptores de Vasopressinas/metabolismo , Análise Espectral Raman , Água/químicaRESUMO
The chemokine CXCL12 and the receptor CXCR4 play pivotal roles in normal vascular and neuronal development, in inflammatory responses, and in infectious diseases and cancer. For instance, CXCL12 has been shown to mediate human immunodeficiency virus-induced neurotoxicity, proliferative retinopathy and chronic inflammation, whereas its receptor CXCR4 is involved in human immunodeficiency virus infection, cancer metastasis and in the rare disease known as the warts, hypogammaglobulinemia, immunodeficiency, and myelokathexis (WHIM) syndrome. As we screened chemical libraries to find inhibitors of the interaction between CXCL12 and the receptor CXCR4, we identified synthetic compounds from the family of chalcones that reduce binding of CXCL12 to CXCR4, inhibit calcium responses mediated by the receptor, and prevent CXCR4 internalization in response to CXCL12. We found that the chemical compounds display an original mechanism of action as they bind to the chemokine but not to CXCR4. The highest affinity molecule blocked chemotaxis of human peripheral blood lymphocytes ex vivo. It was also active in vivo in a mouse model of allergic eosinophilic airway inflammation in which we detected inhibition of the inflammatory infiltrate. The compound showed selectivity for CXCL12 and not for CCL5 and CXCL8 chemokines and blocked CXCL12 binding to its second receptor, CXCR7. By analogy to the effect of neutralizing antibodies, this molecule behaves as a small organic neutralizing compound that may prove to have valuable pharmacological and therapeutic potential.