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1.
Hum Mol Genet ; 2024 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-38776952

RESUMO

Pulmonary arterial hypertension (PAH) is a disorder with a large genetic component. Biallelic mutations of EIF2AK4, which encodes the kinase GCN2, are causal in two ultra-rare subtypes of PAH, pulmonary veno-occlusive disease and pulmonary capillary haemangiomatosis. EIF2AK4 variants of unknown significance have also been identified in patients with classical PAH, though their relationship to disease remains unclear. To provide patients with diagnostic information and enable family testing, the functional consequences of such rare variants must be determined, but existing computational methods are imperfect. We applied a suite of bioinformatic and experimental approaches to sixteen EIF2AK4 variants that had been identified in patients. By experimentally testing the functional integrity of the integrated stress response (ISR) downstream of GCN2, we determined that existing computational tools have insufficient sensitivity to reliably predict impaired kinase function. We determined experimentally that several EIF2AK4 variants identified in patients with classical PAH had preserved function and are therefore likely to be non-pathogenic. The dysfunctional variants of GCN2 that we identified could be subclassified into three groups: misfolded, kinase-dead, and hypomorphic. Intriguingly, members of the hypomorphic group were amenable to paradoxical activation by a type-1½ GCN2 kinase inhibitor. This experiment approach may aid in the clinical stratification of EIF2AK4 variants and potentially identify hypomorophic alleles receptive to pharmacological activation.

2.
Blood ; 143(22): 2314-2331, 2024 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-38457357

RESUMO

ABSTRACT: For monogenic diseases caused by pathogenic loss-of-function DNA variants, attention focuses on dysregulated gene-specific pathways, usually considering molecular subtypes together within causal genes. To better understand phenotypic variability in hereditary hemorrhagic telangiectasia (HHT), we subcategorized pathogenic DNA variants in ENG/endoglin, ACVRL1/ALK1, and SMAD4 if they generated premature termination codons (PTCs) subject to nonsense-mediated decay. In 3 patient cohorts, a PTC-based classification system explained some previously puzzling hemorrhage variability. In blood outgrowth endothelial cells (BOECs) derived from patients with ACVRL1+/PTC, ENG+/PTC, and SMAD4+/PTC genotypes, PTC-containing RNA transcripts persisted at low levels (8%-23% expected, varying between replicate cultures); genes differentially expressed to Bonferroni P < .05 in HHT+/PTC BOECs clustered significantly only to generic protein terms (isopeptide-bond/ubiquitin-like conjugation) and pulse-chase experiments detected subtle protein maturation differences but no evidence for PTC-truncated protein. BOECs displaying highest PTC persistence were discriminated in unsupervised hierarchical clustering of near-invariant housekeeper genes, with patterns compatible with higher cellular stress in BOECs with >11% PTC persistence. To test directionality, we used a HeLa reporter system to detect induction of activating transcription factor 4 (ATF4), which controls expression of stress-adaptive genes, and showed that ENG Q436X but not ENG R93X directly induced ATF4. AlphaFold accurately modeled relevant ENG domains, with AlphaMissense suggesting that readthrough substitutions would be benign for ENG R93X and other less rare ENG nonsense variants but more damaging for Q436X. We conclude that PTCs should be distinguished from other loss-of-function variants, PTC transcript levels increase in stressed cells, and readthrough proteins and mechanisms provide promising research avenues.


Assuntos
Receptores de Activinas Tipo II , Códon sem Sentido , Endoglina , Telangiectasia Hemorrágica Hereditária , Humanos , Telangiectasia Hemorrágica Hereditária/genética , Telangiectasia Hemorrágica Hereditária/patologia , Endoglina/genética , Endoglina/metabolismo , Receptores de Activinas Tipo II/genética , Proteína Smad4/genética , Células Endoteliais/metabolismo , Células Endoteliais/patologia , Mutação , Masculino , Feminino , Degradação do RNAm Mediada por Códon sem Sentido
3.
Eur Respir J ; 63(1)2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38212075

RESUMO

The pleural lining of the thorax regulates local immunity, inflammation and repair. A variety of conditions, both benign and malignant, including pleural mesothelioma, can affect this tissue. A lack of knowledge concerning the mesothelial and stromal cells comprising the pleura has hampered the development of targeted therapies. Here, we present the first comprehensive single-cell transcriptomic atlas of the human parietal pleura and demonstrate its utility in elucidating pleural biology. We confirm the presence of known universal fibroblasts and describe novel, potentially pleural-specific, fibroblast subtypes. We also present transcriptomic characterisation of multiple in vitro models of benign and malignant mesothelial cells, and characterise these through comparison with in vivo transcriptomic data. While bulk pleural transcriptomes have been reported previously, this is the first study to provide resolution at the single-cell level. We expect our pleural cell atlas will prove invaluable to those studying pleural biology and disease. It has already enabled us to shed light on the transdifferentiation of mesothelial cells, allowing us to develop a simple method for prolonging mesothelial cell differentiation in vitro.


Assuntos
Mesotelioma Maligno , Mesotelioma , Neoplasias Pleurais , Humanos , Pleura/patologia , Mesotelioma/genética , Mesotelioma/patologia , Mesotelioma Maligno/patologia , Neoplasias Pleurais/genética , Neoplasias Pleurais/patologia , Perfilação da Expressão Gênica
4.
Thorax ; 77(2): 196-198, 2022 02.
Artigo em Inglês | MEDLINE | ID: mdl-34145047

RESUMO

Familial spontaneous pneumothorax (FSP) accounts for 10% of primary spontaneous pneumothoraces. Appropriate investigation of FSP enables early diagnosis of serious monogenic diseases and the practice of precision medicine. Here, we show that a pneumothorax genetics multidisciplinary team (MDT) can efficiently diagnose a range of syndromic causes of FSP. A sizeable group (73.6%) of clinically unclassifiable FSPs remains. Using whole genome sequencing we demonstrate that most of these cases are not known monogenic disorders. Therefore, clinico-radiological assessment by an MDT has high sensitivity for currently known clinically important monogenic causes of FSP, which has relevance for the design of efficient pneumothorax services.


Assuntos
Pneumotórax , Humanos , Pneumotórax/diagnóstico por imagem , Pneumotórax/genética , Pneumotórax/terapia , Medicina de Precisão
5.
Eur Respir J ; 59(1)2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34049951

RESUMO

BACKGROUND: Alveolar epithelial cell dysfunction plays an important role in the pathogenesis of idiopathic pulmonary fibrosis (IPF), but remains incompletely understood. Some monogenic forms of pulmonary fibrosis are associated with expression of mutant surfactant protein C (SFTPC). The commonest pathogenic mutant, I73T, mislocalises to the alveolar epithelial cell plasma membrane and displays a toxic gain of function. Because the mechanisms explaining the link between this mutant and IPF are incompletely understood, we sought to interrogate SFTPC trafficking in health and disease to understand the functional significance of SFTPC-I73T relocalisation. METHODS: We performed mechanistic analysis of SFTPC trafficking in a cell model that reproduces the in vivo phenotype and validated findings in human primary alveolar organoids. RESULTS: We show that wild-type SFTPC takes an unexpected indirect trafficking route via the plasma membrane and undergoes the first of multiple cleavage events before reaching the multivesicular body (MVB) for further processing. SFTPC-I73T takes this same route, but its progress is retarded both at the cell surface and due to failure of trafficking into the MVB. Unable to undergo onward trafficking, it is recycled to the plasma membrane as a partially cleaved intermediate. CONCLUSION: These data show for the first time that all SFTPC transits the cell surface during normal trafficking, and the I73T mutation accumulates at the cell surface through both retarded trafficking and active recycling. This understanding of normal SFTPC trafficking and how the I73T mutant disturbs it provides novel insight into SFTPC biology in health and disease, and in the contribution of the SFTPC mutant to IPF development.


Assuntos
Fibrose Pulmonar Idiopática , Proteína C Associada a Surfactante Pulmonar/metabolismo , Células Epiteliais Alveolares , Humanos , Fibrose Pulmonar Idiopática/genética , Mutação , Proteína C Associada a Surfactante Pulmonar/genética , Tensoativos
6.
J Asthma ; 59(8): 1577-1583, 2022 08.
Artigo em Inglês | MEDLINE | ID: mdl-34112043

RESUMO

Objectives: The impulse oscillometry system (IOS) provides an alternative method of lung function testing for patients in whom forced expiratory manoeuvres are contraindicated, such as those with inherited vascular connective tissue disorders. Here we examine the role of IOS in the diagnosis and monitoring of asthma in such patients through a clinical case series and literature review.Methods: The clinical case series comprised of data from 12 patients with inherited connective tissue disorders representing 32 clinical encounters. Of these, 11 encounters were for asthma diagnosis and 21 were for asthma monitoring. Symptoms, exhaled nitric oxide (FeNO) and IOS were assessed at each encounter.Results: In the clinical case series, 5 of 6 patients with likely asthma (as determined by physician review and exhaled nitric oxide testing) had abnormal IOS parameters compared with 0 of 5 of those with unlikely asthma. In the monitoring group, 11 encounters resulted in treatment escalation (demonstrating suboptimal control), and 8 resulted in no change to treatment (good control). Six of 11 of those with suboptimal control had abnormalities in ≥3 IOS parameters, with R5 and R5-20 most frequently affected. Only 1 of 8 of those with good control had abnormalities in ≥3 IOS parameters.Conclusions: IOS can be used as an alternative to conventional lung function testing to support the diagnosis and monitoring of asthma when forced expiratory manoeuvres are contraindicated. Larger studies are required to establish severity and treatment escalation thresholds and provide clearer comparisons with spirometry values.


Assuntos
Asma , Asma/tratamento farmacológico , Asma/terapia , Volume Expiratório Forçado , Humanos , Óxido Nítrico , Oscilometria/métodos , Testes de Função Respiratória/métodos , Espirometria/métodos
7.
Br J Cancer ; 125(8): 1039-1055, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34226685

RESUMO

Mesothelioma is an aggressive cancer that is associated with exposure to asbestos. Although asbestos is banned in several countries, including the UK, an epidemic of mesothelioma is predicted to affect middle-income countries during this century owing to their heavy consumption of asbestos. The prognosis for patients with mesothelioma is poor, reflecting a failure of conventional chemotherapy that has ultimately resulted from an inadequate understanding of its biology. However, recent work has revolutionised the study of mesothelioma, identifying genetic and pathophysiological vulnerabilities, including the loss of tumour suppressors, epigenetic dysregulation and susceptibility to nutrient stress. We discuss how this knowledge, combined with advances in immunotherapy, is enabling the development of novel targeted therapies.


Assuntos
Amianto/toxicidade , Redes Reguladoras de Genes , Mesotelioma/terapia , Terapia Combinada , Epigênese Genética , Humanos , Mesotelioma/induzido quimicamente , Mesotelioma/genética , Mesotelioma/patologia , Prognóstico
8.
Lancet ; 396(10243): 39-49, 2020 07 04.
Artigo em Inglês | MEDLINE | ID: mdl-32622394

RESUMO

BACKGROUND: Primary spontaneous pneumothorax occurs in otherwise healthy young patients. Optimal management is not defined and often results in prolonged hospitalisation. Data on efficacy of ambulatory options are poor. We aimed to describe the duration of hospitalisation and safety of ambulatory management compared with standard care. METHODS: In this open-label, randomised controlled trial, adults (aged 16-55 years) with symptomatic primary spontaneous pneumothorax were recruited from 24 UK hospitals during a period of 3 years. Patients were randomly assigned (1:1) to treatment with either an ambulatory device or standard guideline-based management (aspiration, standard chest tube insertion, or both). The primary outcome was total length of hospital stay including re-admission up to 30 days after randomisation. Patients with available data were included in the primary analysis and all assigned patients were included in the safety analysis. The trial was prospectively registered with the International Standard Randomised Clinical Trials Number, ISRCTN79151659. FINDINGS: Of 776 patients screened between July, 2015, and March, 2019, 236 (30%) were randomly assigned to ambulatory care (n=117) and standard care (n=119). At day 30, the median hospitalisation was significantly shorter in the 114 patients with available data who received ambulatory treatment (0 days [IQR 0-3]) than in the 113 with available data who received standard care (4 days [IQR 0-8]; p<0·0001; median difference 2 days [95% CI 1-3]). 110 (47%) of 236 patients had adverse events, including 64 (55%) of 117 patients in the ambulatory care arm and 46 (39%) of 119 in the standard care arm. All 14 serious adverse events occurred in patients who received ambulatory care, eight (57%) of which were related to the intervention, including an enlarging pneumothorax, asymptomatic pulmonary oedema, and the device malfunctioning, leaking, or dislodging. INTERPRETATION: Ambulatory management of primary spontaneous pneumothorax significantly reduced the duration of hospitalisation including re-admissions in the first 30 days, but at the expense of increased adverse events. This data suggests that primary spontaneous pneumothorax can be managed for outpatients, using ambulatory devices in those who require intervention. FUNDING: UK National Institute for Health Research.


Assuntos
Assistência Ambulatorial/estatística & dados numéricos , Tempo de Internação/estatística & dados numéricos , Readmissão do Paciente/estatística & dados numéricos , Pneumotórax/terapia , Padrão de Cuidado , Adulto , Feminino , Hospitalização , Humanos , Masculino , Reino Unido
9.
Thorax ; 76(11): 1154-1162, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-33692175

RESUMO

Malignant pleural mesothelioma (MPM) is an aggressive cancer most commonly caused by prior exposure to asbestos. Median survival is 12-18 months, since surgery is ineffective and chemotherapy offers minimal benefit. Preclinical models that faithfully recapitulate the genomic and histopathological features of cancer are critical for the development of new treatments. The most commonly used models of MPM are two-dimensional cell lines established from primary tumours or pleural fluid. While these have provided some important insights into MPM biology, these cell models have significant limitations. In order to address some of these limitations, spheroids and microfluidic chips have more recently been used to investigate the role of the three-dimensional environment in MPM. Efforts have also been made to develop animal models of MPM, including asbestos-induced murine tumour models, MPM-prone genetically modified mice and patient-derived xenografts. Here, we discuss the available in vitro and in vivo models of MPM and highlight their strengths and limitations. We discuss how newer technologies, such as the tumour-derived organoids, might allow us to address the limitations of existing models and aid in the identification of effective treatments for this challenging-to-treat disease.


Assuntos
Amianto , Neoplasias Pulmonares , Mesotelioma Maligno , Mesotelioma , Neoplasias Pleurais , Animais , Camundongos
10.
Thorax ; 76(1): 92-99, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-33077618

RESUMO

The lungs are exposed to a range of environmental toxins (including cigarette smoke, air pollution, asbestos) and pathogens (bacterial, viral and fungal), and most respiratory diseases are associated with local or systemic hypoxia. All of these adverse factors can trigger endoplasmic reticulum (ER) stress. The ER is a key intracellular site for synthesis of secretory and membrane proteins, regulating their folding, assembly into complexes, transport and degradation. Accumulation of misfolded proteins within the lumen results in ER stress, which activates the unfolded protein response (UPR). Effectors of the UPR temporarily reduce protein synthesis, while enhancing degradation of misfolded proteins and increasing the folding capacity of the ER. If successful, homeostasis is restored and protein synthesis resumes, but if ER stress persists, cell death pathways are activated. ER stress and the resulting UPR occur in a range of pulmonary insults and the outcome plays an important role in many respiratory diseases. The UPR is triggered in the airway of patients with several respiratory diseases and in corresponding experimental models. ER stress has been implicated in the initiation and progression of pulmonary fibrosis, and evidence is accumulating suggesting that ER stress occurs in obstructive lung diseases (particularly in asthma), in pulmonary infections (some viral infections and in the setting of the cystic fibrosis airway) and in lung cancer. While a number of small molecule inhibitors have been used to interrogate the role of the UPR in disease models, many of these tools have complex and off-target effects, hence additional evidence (eg, from genetic manipulation) may be required to support conclusions based on the impact of such pharmacological agents. Aberrant activation of the UPR may be linked to disease pathogenesis and progression, but at present, our understanding of the context-specific and disease-specific mechanisms linking these processes is incomplete. Despite this, the ability of the UPR to defend against ER stress and influence a range of respiratory diseases is becoming increasingly evident, and the UPR is therefore attracting attention as a prospective target for therapeutic intervention strategies.


Assuntos
Estresse do Retículo Endoplasmático , Pneumopatias/metabolismo , Proteínas de Membrana/fisiologia , Humanos , Transdução de Sinais
11.
Eur Respir J ; 56(5)2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32907891

RESUMO

INTRODUCTION: Pneumothorax and pneumomediastinum have both been noted to complicate cases of coronavirus disease 2019 (COVID-19) requiring hospital admission. We report the largest case series yet described of patients with both these pathologies (including nonventilated patients). METHODS: Cases were collected retrospectively from UK hospitals with inclusion criteria limited to a diagnosis of COVID-19 and the presence of either pneumothorax or pneumomediastinum. Patients included in the study presented between March and June 2020. Details obtained from the medical record included demographics, radiology, laboratory investigations, clinical management and survival. RESULTS: 71 patients from 16 centres were included in the study, of whom 60 had pneumothoraces (six with pneumomediastinum in addition) and 11 had pneumomediastinum alone. Two of these patients had two distinct episodes of pneumothorax, occurring bilaterally in sequential fashion, bringing the total number of pneumothoraces included to 62. Clinical scenarios included patients who had presented to hospital with pneumothorax, patients who had developed pneumothorax or pneumomediastinum during their inpatient admission with COVID-19 and patients who developed their complication while intubated and ventilated, either with or without concurrent extracorporeal membrane oxygenation. Survival at 28 days was not significantly different following pneumothorax (63.1±6.5%) or isolated pneumomediastinum (53.0±18.7%; p=0.854). The incidence of pneumothorax was higher in males. 28-day survival was not different between the sexes (males 62.5±7.7% versus females 68.4±10.7%; p=0.619). Patients aged ≥70 years had a significantly lower 28-day survival than younger individuals (≥70 years 41.7±13.5% survival versus <70 years 70.9±6.8% survival; p=0.018 log-rank). CONCLUSION: These cases suggest that pneumothorax is a complication of COVID-19. Pneumothorax does not seem to be an independent marker of poor prognosis and we encourage continuation of active treatment where clinically possible.


Assuntos
COVID-19/complicações , Enfisema Mediastínico/epidemiologia , Enfisema Mediastínico/virologia , Pneumotórax/epidemiologia , Pneumotórax/virologia , SARS-CoV-2 , Adulto , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , COVID-19/mortalidade , COVID-19/terapia , Oxigenação por Membrana Extracorpórea , Feminino , Hospitalização , Humanos , Incidência , Masculino , Enfisema Mediastínico/terapia , Pessoa de Meia-Idade , Pneumotórax/terapia , Prognóstico , Respiração Artificial , Estudos Retrospectivos , Fatores Sexuais , Taxa de Sobrevida , Reino Unido , Adulto Jovem
12.
Small ; 16(46): e2003793, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-33103323

RESUMO

The generation of effective and safe nanoagents for biological applications requires their physicochemical characteristics to be tunable, and their cellular interactions to be well characterized. Here, the controlled synthesis is developed for preparing high-aspect ratio gold nanotubes (AuNTs) with tailorable wall thickness, microstructure, composition, and optical characteristics. The modulation of optical properties generates AuNTs with strong near infrared absorption. Surface modification enhances dispersibility of AuNTs in aqueous media and results in low cytotoxicity. The uptake and trafficking of these AuNTs by primary mesothelioma cells demonstrate their accumulation in a perinuclear distribution where they are confined initially in membrane-bound vesicles from which they ultimately escape to the cytosol. This represents the first study of the cellular interactions of high-aspect ratio 1D metal nanomaterials and will facilitate the rational design of plasmonic nanoconstructs as cytosolic nanoagents for potential diagnosis and therapeutic applications.


Assuntos
Mesotelioma , Nanoestruturas , Nanotubos , Citosol , Ouro , Humanos , Mesotelioma/tratamento farmacológico
13.
J Transl Med ; 18(1): 341, 2020 09 04.
Artigo em Inglês | MEDLINE | ID: mdl-32887638

RESUMO

BACKGROUND: Malignant pleural mesothelioma (MPM) is an aggressive neoplasm of the pleura, mainly related to asbestos exposure. As in other solid tumors, malignant cells exhibit high glucose uptake and glycolytic rates with increased lactic acid efflux into the interstitial space. Lactate transport into and out of cells, crucial to maintaining intracellular pH homeostasis and glycolysis, is carried out by monocarboxylate transporters (MCTs) and the chaperone basigin (CD147). We set out to examine the clinical significance of basigin, MCT1 and MCT4 in the context of MPM and to evaluate their expression in relation to the evolution of the disease. METHODS: We used immunohistochemistry to measure the expression of basigin, MCT1 and MCT4 in a cohort of 135 individuals with MPM compared to a series of 15 non-MPM pleura specimens. Moreover, by Kaplan-Meier and Cox analyses we evaluated whether an expression over the average of these markers could be associated with the patients' overall survival (OS). RESULTS: We detected positive staining of basigin, MCT1, and MCT4 in most MPM specimens. In particular, MCT4 was always positive in malignant tissues but undetectable in the 4 normal pleural specimens incorporated within the tissue microarray. This was confirmed in the additional series of 15 normal pleural samples. Moreover, MCT4 expression was significantly associated with reduced OS. CONCLUSION: In this study, the tissue expression of basigin did not prove to be exploitable as a diagnostic or prognostic marker for MPM patients. The expression of MCT1 was not informative either, being tightly correlated with that of basigin. However, the expression of MCT4 showed promise as a diagnostic/therapeutic and prognostic biomarker.


Assuntos
Mesotelioma Maligno , Simportadores , Basigina/metabolismo , Humanos , Transportadores de Ácidos Monocarboxílicos , Proteínas Musculares/metabolismo , Prognóstico
14.
Nature ; 510(7504): 268-72, 2014 Jun 12.
Artigo em Inglês | MEDLINE | ID: mdl-24776803

RESUMO

The blood system is sustained by a pool of haematopoietic stem cells (HSCs) that are long-lived due to their capacity for self-renewal. A consequence of longevity is exposure to stress stimuli including reactive oxygen species (ROS), nutrient fluctuation and DNA damage. Damage that occurs within stressed HSCs must be tightly controlled to prevent either loss of function or the clonal persistence of oncogenic mutations that increase the risk of leukaemogenesis. Despite the importance of maintaining cell integrity throughout life, how the HSC pool achieves this and how individual HSCs respond to stress remain poorly understood. Many sources of stress cause misfolded protein accumulation in the endoplasmic reticulum (ER), and subsequent activation of the unfolded protein response (UPR) enables the cell to either resolve stress or initiate apoptosis. Here we show that human HSCs are predisposed to apoptosis through strong activation of the PERK branch of the UPR after ER stress, whereas closely related progenitors exhibit an adaptive response leading to their survival. Enhanced ER protein folding by overexpression of the co-chaperone ERDJ4 (also called DNAJB9) increases HSC repopulation capacity in xenograft assays, linking the UPR to HSC function. Because the UPR is a focal point where different sources of stress converge, our study provides a framework for understanding how stress signalling is coordinated within tissue hierarchies and integrated with stemness. Broadly, these findings reveal that the HSC pool maintains clonal integrity by clearance of individual HSCs after stress to prevent propagation of damaged stem cells.


Assuntos
Estresse do Retículo Endoplasmático , Células-Tronco Hematopoéticas/citologia , Resposta a Proteínas não Dobradas/fisiologia , Fator 4 Ativador da Transcrição/metabolismo , Animais , Apoptose/efeitos dos fármacos , Estresse do Retículo Endoplasmático/efeitos dos fármacos , Fator de Iniciação 2 em Eucariotos/metabolismo , Proteínas de Choque Térmico HSP40/metabolismo , Células-Tronco Hematopoéticas/efeitos dos fármacos , Xenoenxertos , Humanos , Masculino , Proteínas de Membrana/metabolismo , Camundongos , Chaperonas Moleculares/metabolismo , Dobramento de Proteína , Proteína Fosfatase 1/metabolismo , Transdução de Sinais , Fator de Transcrição CHOP/metabolismo , Tunicamicina/farmacologia , Resposta a Proteínas não Dobradas/efeitos dos fármacos , eIF-2 Quinase/metabolismo
15.
Am J Respir Crit Care Med ; 199(11): 1344-1357, 2019 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-30681372

RESUMO

A genetic influence on spontaneous pneumothoraces-those occurring without a traumatic or iatrogenic cause-is supported by several lines of evidence: 1) pneumothorax can cluster in families (i.e., familial spontaneous pneumothorax), 2) mutations in the FLCN gene have been found in both familial and sporadic cases, and 3) pneumothorax is a known complication of several genetic syndromes. Herein, we review known genetic contributions to both sporadic and familial pneumothorax. We summarize the pneumothorax-associated genetic syndromes, including Birt-Hogg-Dubé syndrome, Marfan syndrome, vascular (type IV) Ehlers-Danlos syndrome, alpha-1 antitrypsin deficiency, tuberous sclerosis complex/lymphangioleiomyomatosis, Loeys-Dietz syndrome, cystic fibrosis, homocystinuria, and cutis laxa, among others. At times, pneumothorax is their herald manifestation. These syndromes have serious potential extrapulmonary complications (e.g., malignant renal tumors in Birt-Hogg-Dubé syndrome), and surveillance and/or treatment is available for most disorders; thus, establishing a diagnosis is critical. To facilitate this, we provide an algorithm to guide the clinician in discerning which cases of spontaneous pneumothorax may have a genetic or familial contribution, which cases warrant genetic testing, and which cases should prompt an evaluation by a geneticist.


Assuntos
Síndrome de Birt-Hogg-Dubé/genética , Pneumotórax/genética , Proteínas Proto-Oncogênicas/genética , Proteínas Supressoras de Tumor/genética , Predisposição Genética para Doença , Testes Genéticos , Humanos , Mutação , Linhagem
16.
Biol Cell ; 110(11): 249-255, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-30129166

RESUMO

An important function of the endoplasmic reticulum (ER) is to serve as a site of secretory protein folding. When the accumulation of misfolded proteins threatens to disturb luminal homoeostasis, the cell is said to experience ER stress. By contrast, the accumulation of well-folded proteins inside the ER leads to a distinct form of strain called ER overload. The serpins comprise a large family of proteins whose folding has been studied in great detail. Some mutant serpins misfold to cause ER stress, whereas others fold but then polymerise to cause ER overload. We discuss recent advances in the use of dynamic fluorescence imaging to study these phenomena. We also discuss a new technique that we recently published, rotor-based organelle viscosity imaging (ROVI), which promises to shed more light on the biophysical features of ER stress and ER overload.


Assuntos
Fenômenos Biofísicos , Retículo Endoplasmático/metabolismo , Retículo Endoplasmático/ultraestrutura , Polimerização , alfa 1-Antitripsina/metabolismo , Animais , Humanos , Corpos de Inclusão/metabolismo , Viscosidade
17.
Nature ; 503(7475): 272-6, 2013 Nov 14.
Artigo em Inglês | MEDLINE | ID: mdl-24089213

RESUMO

The recognition of autophagy related 16-like 1 (ATG16L1) as a genetic risk factor has exposed the critical role of autophagy in Crohn's disease. Homozygosity for the highly prevalent ATG16L1 risk allele, or murine hypomorphic (HM) activity, causes Paneth cell dysfunction. As Atg16l1(HM) mice do not develop spontaneous intestinal inflammation, the mechanism(s) by which ATG16L1 contributes to disease remains obscure. Deletion of the unfolded protein response (UPR) transcription factor X-box binding protein-1 (Xbp1) in intestinal epithelial cells, the human orthologue of which harbours rare inflammatory bowel disease risk variants, results in endoplasmic reticulum (ER) stress, Paneth cell impairment and spontaneous enteritis. Unresolved ER stress is a common feature of inflammatory bowel disease epithelium, and several genetic risk factors of Crohn's disease affect Paneth cells. Here we show that impairment in either UPR (Xbp1(ΔIEC)) or autophagy function (Atg16l1(ΔIEC) or Atg7(ΔIEC)) in intestinal epithelial cells results in each other's compensatory engagement, and severe spontaneous Crohn's-disease-like transmural ileitis if both mechanisms are compromised. Xbp1(ΔIEC) mice show autophagosome formation in hypomorphic Paneth cells, which is linked to ER stress via protein kinase RNA-like endoplasmic reticulum kinase (PERK), elongation initiation factor 2α (eIF2α) and activating transcription factor 4 (ATF4). Ileitis is dependent on commensal microbiota and derives from increased intestinal epithelial cell death, inositol requiring enzyme 1α (IRE1α)-regulated NF-κB activation and tumour-necrosis factor signalling, which are synergistically increased when autophagy is deficient. ATG16L1 restrains IRE1α activity, and augmentation of autophagy in intestinal epithelial cells ameliorates ER stress-induced intestinal inflammation and eases NF-κB overactivation and intestinal epithelial cell death. ER stress, autophagy induction and spontaneous ileitis emerge from Paneth-cell-specific deletion of Xbp1. Genetically and environmentally controlled UPR function within Paneth cells may therefore set the threshold for the development of intestinal inflammation upon hypomorphic ATG16L1 function and implicate ileal Crohn's disease as a specific disorder of Paneth cells.


Assuntos
Enteropatias/fisiopatologia , Mucosa Intestinal/patologia , Celulas de Paneth/patologia , Animais , Autofagia/genética , Proteínas Relacionadas à Autofagia , Proteínas de Transporte/genética , Proteínas de Transporte/metabolismo , Linhagem Celular , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Estresse do Retículo Endoplasmático/genética , Inflamação , Enteropatias/genética , Mucosa Intestinal/citologia , Camundongos , Fatores de Transcrição de Fator Regulador X , Transdução de Sinais , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Resposta a Proteínas não Dobradas/fisiologia , Proteína 1 de Ligação a X-Box , eIF-2 Quinase/metabolismo
18.
BMC Biol ; 16(1): 34, 2018 04 03.
Artigo em Inglês | MEDLINE | ID: mdl-29609607

RESUMO

BACKGROUND: Developmental pathways must be responsive to the environment. Phosphorylation of eIF2α enables a family of stress-sensing kinases to trigger the integrated stress response (ISR), which has pro-survival and developmental consequences. Bone morphogenetic proteins (BMPs) regulate multiple developmental processes in organisms from insects to mammals. RESULTS: Here we show in Drosophila that GCN2 antagonises BMP signalling through direct effects on translation and indirectly via the transcription factor crc (dATF4). Expression of a constitutively active GCN2 or loss of the eIF2α phosphatase dPPP1R15 impairs developmental BMP signalling in flies. In cells, inhibition of translation by GCN2 blocks downstream BMP signalling. Moreover, loss of d4E-BP, a target of crc, augments BMP signalling in vitro and rescues tissue development in vivo. CONCLUSION: These results identify a novel mechanism by which the ISR modulates BMP signalling during development.


Assuntos
Proteínas de Drosophila/metabolismo , Transdução de Sinais/fisiologia , Animais , Proteínas Morfogenéticas Ósseas/genética , Proteínas Morfogenéticas Ósseas/metabolismo , Drosophila , Proteínas de Drosophila/genética , Fator de Iniciação 2 em Eucariotos/genética , Fator de Iniciação 2 em Eucariotos/metabolismo , Regulação da Expressão Gênica/genética , Regulação da Expressão Gênica/fisiologia , Fosforilação , Proteínas Quinases/genética , Proteínas Quinases/metabolismo , Transdução de Sinais/genética
19.
J Hepatol ; 69(4): 851-860, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-29879455

RESUMO

BACKGROUND & AIMS: α1-Antitrypsin deficiency (A1ATD) is an autosomal recessive disorder caused by mutations in the SERPINA1 gene. Individuals with the Z variant (Gly342Lys) retain polymerised protein in the endoplasmic reticulum (ER) of their hepatocytes, predisposing them to liver disease. The concomitant lack of circulating A1AT also causes lung emphysema. Greater insight into the mechanisms that link protein misfolding to liver injury will facilitate the design of novel therapies. METHODS: Human-induced pluripotent stem cell (hiPSC)-derived hepatocytes provide a novel approach to interrogate the molecular mechanisms of A1ATD because of their patient-specific genetic architecture and reflection of human physiology. To that end, we utilised patient-specific hiPSC hepatocyte-like cells (ZZ-HLCs) derived from an A1ATD (ZZ) patient, which faithfully recapitulated key aspects of the disease at the molecular and cellular level. Subsequent functional and "omics" comparisons of these cells with their genetically corrected isogenic-line (RR-HLCs) and primary hepatocytes/human tissue enabled identification of new molecular markers and disease signatures. RESULTS: Our studies showed that abnormal A1AT polymer processing (immobilised ER components, reduced luminal protein mobility and disrupted ER cisternae) occurred heterogeneously within hepatocyte populations and was associated with disrupted mitochondrial structure, presence of the oncogenic protein AKR1B10 and two upregulated molecular clusters centred on members of inflammatory (IL-18 and Caspase-4) and unfolded protein response (Calnexin and Calreticulin) pathways. These results were validated in a second patient-specific hiPSC line. CONCLUSIONS: Our data identified novel pathways that potentially link the expression of Z A1AT polymers to liver disease. These findings could help pave the way towards identification of new therapeutic targets for the treatment of A1ATD. LAY SUMMARY: This study compared the gene expression and protein profiles of healthy liver cells and those affected by the inherited disease α1-antitrypsin deficiency. This approach identified specific factors primarily present in diseased samples which could provide new targets for drug development. This study also demonstrates the interest of using hepatic cells generated from human-induced pluripotent stem cells to model liver disease in vitro for uncovering new mechanisms with clinical relevance.


Assuntos
Hepatócitos/citologia , Células-Tronco Pluripotentes Induzidas/fisiologia , Inflamação/complicações , Resposta a Proteínas não Dobradas/fisiologia , Deficiência de alfa 1-Antitripsina/etiologia , Células Cultivadas , Retículo Endoplasmático/fisiologia , Humanos , alfa 1-Antitripsina/genética
20.
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