RESUMO
Bronchial airways and lung parenchyma undergo both static and dynamic stretch in response to normal breathing but also in the context of insults such as mechanical ventilation (MV) or in diseases such as asthma and COPD which lead to airway remodeling involving increased extracellular matrix (ECM) production. Here, the role of fibroblasts is critical, but the relationship between stretch and fibroblast induced ECM remodeling under these conditions is not well-explored. Piezo (PZ) channels play a role in mechanotransduction in many cell and organ systems, but their role in mechanical stretch-induced airway remodeling is not known. To explore this, we exposed human lung fibroblasts to 10% static stretch on a background of 5% oscillations for 48 hours, with no static stretch considered controls. Collagen I, Fibronectin, α-SMA, and Piezo 1 (PZ1) expression were determined in the presence or absence of Yoda1 (PZ1 agonist) or GsMTx4 (PZ1 inhibitor). Collagen I, Fibronectin, and α-SMA expression was increased by stretch and Yoda1 while pretreatment with GsMTx4 or knockdown of PZ1 by siRNA blunted this effect. Acute stretch in the presence and absence of Yoda1 demonstrated activation of ERK pathway but not Smad. Measurement of [Ca2+] i responses to histamine showed significantly greater responses following stretch: effects that were blunted by knockdown of PZ1.Our findings identify an essential role for PZ1 in mechanical stretch-induced production of ECM mediated by ERK phosphorylation and Ca2+ influx in lung fibroblasts. Targeting PZ channels in fibroblasts may constitute a novel approach to ameliorate airway remodeling by decreasing ECM deposition.
RESUMO
Alteration in the normal mechanical forces of breathing can contribute to changes in contractility and remodeling characteristic of airway diseases, but the mechanisms that mediate these effects in airway cells are still under investigation. Airway smooth muscle (ASM) cells contribute to both contractility and extracellular matrix (ECM) remodeling. In this study, we explored ASM mechanisms activated by mechanical stretch, focusing on mechanosensitive piezo channels and the key Ca2+ regulatory protein stromal interaction molecule 1 (STIM1). Expression of Ca2+ regulatory proteins, including STIM1, Orai1, and caveolin-1, mechanosensitive ion channels Piezo-1 and Piezo-2, and NLRP3 inflammasomes were upregulated by 10% static stretch superimposed on 5% cyclic stretch. These effects were blunted by STIM1 siRNA. Histamine-induced [Ca2+]i responses and inflammasome activation were similarly blunted by STIM1 knockdown. These data show that the effects of mechanical stretch in human ASM cells are mediated through STIM1, which activates multiple pathways, including Piezo channels and the inflammasome, leading to potential downstream changes in contractility and ECM remodeling.NEW & NOTEWORTHY Mechanical forces on the airway can contribute to altered contractility and remodeling in airway diseases, but the mechanisms are not clearly understood. Using human airway smooth muscle cells exposed to cyclic forces with static stretch to mimic breathing and static pressure, we found that the effects of stretch are mediated through STIM1, resulting in the activation of multiple pathways, including Piezo channels and the inflammasome, with potential downstream influences on contractility and remodeling.
Assuntos
Miócitos de Músculo Liso , Molécula 1 de Interação Estromal , Humanos , Molécula 1 de Interação Estromal/metabolismo , Molécula 1 de Interação Estromal/genética , Miócitos de Músculo Liso/metabolismo , Proteínas de Neoplasias/metabolismo , Proteínas de Neoplasias/genética , Inflamassomos/metabolismo , Estresse Mecânico , Mecanotransdução Celular , Músculo Liso/metabolismo , Canais Iônicos/metabolismo , Caveolina 1/metabolismo , Caveolina 1/genética , Transdução de Sinais , Proteína 3 que Contém Domínio de Pirina da Família NLR/metabolismo , Proteína 3 que Contém Domínio de Pirina da Família NLR/genética , Cálcio/metabolismo , Células Cultivadas , Contração Muscular/fisiologia , Remodelação das Vias Aéreas/fisiologia , Proteína ORAI1/metabolismo , Proteína ORAI1/genéticaRESUMO
Mechanosensitive channels (MS channels) are membrane proteins capable of responding to mechanical stress over a wide dynamic range of external mechanical stimuli. In recent years, it has been found that MS channels play an important role as "sentinels" in the process of cell sensing and response to extracellular and intracellular force signals. There is growing appreciation for mechanical activation of ion channels and their subsequent initiation of downstream signaling pathways. Members of the transient receptor potential (TRP) superfamily and Piezo channels are broadly expressed in human tissues and contribute to multiple cellular functions. Both TRP and Piezo channels are thought to play key roles in physiological homeostasis and pathophysiology of disease states including in the lung. Here, we review the current state of knowledge on the expression, regulation, and function of TRP and Piezo channels in the context of the adult lung across the age spectrum, and in lung diseases such as asthma, COPD and pulmonary fibrosis where mechanical forces likely play varied roles in the structural and functional changes characteristic of these diseases. Understanding of TRP and Piezo in the lung can provide insights into new targets for treatment of pulmonary disease.
RESUMO
INTRODUCTION: Asthma is a chronic lung disease influenced by environmental and inflammatory triggers and involving complex signaling pathways across resident airway cells such as epithelium, airway smooth muscle, fibroblasts, and immune cells. While our understanding of asthma pathophysiology is continually progressing, there is a growing realization that cellular microdomains play critical roles in mediating signaling relevant to asthma in the context of contractility and remodeling. Mechanosensitive pathways are increasingly recognized as important to microdomain signaling, with Piezo and transient receptor protein (TRP) channels at the plasma membrane considered important for converting mechanical stimuli into cellular behavior. Given their ion channel properties, particularly Ca2+ conduction, a question becomes whether and how mechanosensitive channels contribute to Ca2+ microdomains in airway cells relevant to asthma. AREAS COVERED: Mechanosensitive TRP and Piezo channels regulate key Ca2+ regulatory proteins such as store operated calcium entry (SOCE) involving STIM and Orai channels, and sarcoendoplasmic (SR) mechanisms such as IP3 receptor channels (IP3Rs), and SR Ca2+ ATPase (SERCA) that are important in asthma pathophysiology including airway hyperreactivity and remodeling. EXPERT OPINION: Physical and/or functional interactions between Ca2+ regulatory proteins and mechanosensitive channels such as TRP and Piezo can toward understanding asthma pathophysiology and identifying novel therapeutic approaches.
Assuntos
Asma , Cálcio , Humanos , Cálcio/metabolismo , Sinalização do Cálcio/fisiologia , Sistema Respiratório/metabolismo , Membrana Celular/metabolismo , Asma/metabolismoRESUMO
The use of respiratory support strategies such as continuous positive airway pressure in premature infants can substantially stretch highly compliant perinatal airways, leading to airway hyperreactivity and remodeling in the long term. The mechanisms by which stretch detrimentally affects the airway are unknown. Airway smooth muscle cells play a critical role in contractility and remodeling. Using 18-22-wk gestation human fetal airway smooth muscle (fASM) as an in vitro model, we tested the hypothesis that mechanosensitive Piezo (PZ) channels contribute to stretch effects. We found that PZ1 and PZ2 channels are expressed in the smooth muscle of developing airways and that their expression is influenced by stretch. PZ activation via agonist Yoda1 or stretch results in significant [Ca2+]i responses as well as increased extracellular matrix production. These data suggest that functional PZ channels may play a role in detrimental stretch-induced airway changes in the context of prematurity.NEW & NOTEWORTHY Piezo channels were first described just over a decade ago and their function in the lung is largely unknown. We found that piezo channels are present and functional in the developing airway and contribute to intracellular calcium responses and extracellular matrix remodeling in the setting of stretch. This may improve our understanding of the mechanisms behind development of chronic airway diseases, such as asthma, in former preterm infants exposed to respiratory support, such as continuous positive airway pressure (CPAP).
Assuntos
Asma , Recém-Nascido Prematuro , Humanos , Recém-Nascido , Músculo Liso/metabolismo , Pulmão/metabolismo , Asma/metabolismo , Miócitos de Músculo Liso/metabolismoRESUMO
The lung is an inherently mechanosensitive organ, where cells of the airway and parenchyma experience a range of mechanical forces throughout life including shear, stretch, and compression, in both health and disease. In this regard, pediatric and adult lung diseases such as wheezing and asthma, bronchopulmonary dysplasia (BPD), chronic obstructive pulmonary disease (COPD), and pulmonary fibrosis (PF) all involve macroscopic and cellular changes to the mechanical properties of the bronchial airways and/or parenchyma to varying extents. Accordingly, understanding how mechanical forces are sensed in the lung, and the responses of cells and tissues in the context of normal development and health versus disease conditions becomes highly relevant. There is increasing recognition that transduction of mechanical forces into cellular responses involves a number of channels, some of which are inherently mechanosensitive. Such channels trigger mechanotransduction pathways that may further mediate cellular remodeling, inflammation, and other pathophysiologic mechanisms in response to stretch, stiffness, and inflammatory cascades. Two particularly important channel families have emerged in pulmonary pathophysiology: the transient receptor potential vanilloid family with focus on member TRPV4 and the recently identified Piezo (PZ) channels. Here, we explore current understanding of the contributions of TRPV4 and PZ channels in lung health and disease states, focusing on the interactions between these mechanosensitive channels and their local environment including immune cells, the extracellular matrix, and cellular cytoskeletal elements. We further discuss potential areas for future research to better understand the impact of mechanical channels on pulmonary health and disease. © 2023 American Physiological Society. Compr Physiol 13:5157-5178, 2023.
Assuntos
Asma , Fibrose Pulmonar , Adulto , Recém-Nascido , Humanos , Criança , Canais de Cátion TRPV/metabolismo , Mecanotransdução Celular/fisiologia , Pulmão/metabolismo , Fibrose Pulmonar/metabolismoRESUMO
Chronic airway diseases, such as wheezing and asthma, remain significant sources of morbidity and mortality in the pediatric population. This is especially true for preterm infants who are impacted both by immature pulmonary development as well as disproportionate exposure to perinatal insults that may increase the risk of developing airway disease. Chronic pediatric airway disease is characterized by alterations in airway structure (remodeling) and function (increased airway hyperresponsiveness), similar to adult asthma. One of the most common perinatal risk factors for development of airway disease is respiratory support in the form of supplemental oxygen, mechanical ventilation, and/or CPAP. While clinical practice currently seeks to minimize oxygen exposure to decrease the risk of bronchopulmonary dysplasia (BPD), there is mounting evidence that lower levels of oxygen may carry risk for development of chronic airway, rather than alveolar disease. In addition, stretch exposure due to mechanical ventilation or CPAP may also play a role in development of chronic airway disease. Here, we summarize the current knowledge of the impact of perinatal oxygen and mechanical respiratory support on the development of chronic pediatric lung disease, with particular focus on pediatric airway disease. We further highlight mechanisms that could be explored as potential targets for novel therapies in the pediatric population.
RESUMO
A persistent patent ductus arteriosus (PDA) can have significant clinical consequences in preterm infants, depending on the degree of left-to-right shunting, its impact on cardiac performance, and associated perinatal risk factors that can mitigate or exacerbate the shunt. Although the best management strategy remains contentious, PDAs that have contraindications to, or have failed medical management have historically undergone surgical ligation. Recently smaller occluder devices and delivery systems have allowed for minimally invasive closure in the catheterization laboratory even in extremely premature infants. The present review summarizes the pathophysiologic manifestations, treatment options and management of hemodynamically significant PDA in preterm infants. Additionally, we review the available literature surrounding the respiratory support and outcomes of preterm infants following definitive PDA closure.
Assuntos
Permeabilidade do Canal Arterial , Permeabilidade do Canal Arterial/cirurgia , Humanos , Lactente , Lactente Extremamente Prematuro , Recém-Nascido , Fatores de RiscoRESUMO
OBJECTIVE: To determine whether children with Down syndrome (DS) receive higher doses of opioid medications compared with children without DS for repair of complete atrioventricular canal (CAVC). DESIGN: A retrospective chart review of children with and without DS who underwent primary repair of CAVC. The exclusion criteria included unbalanced CAVC and patients undergoing biventricular staging procedures. The primary outcome was oral morphine equivalents (OME) received in the first 24 hours after surgery. The secondary outcomes included intraoperative OME, OME at 48 and 72 hours, nonopioid analgesic and sedative medications received, pain scores, time to extubation, and length of stay. SETTING: A pediatric academic medical center in the United States. PARTICIPANTS: One hundred thirty-one patients with DS and 24 without, all Assuntos
Procedimentos Cirúrgicos Cardíacos
, Síndrome de Down
, Analgésicos Opioides
, Criança
, Pré-Escolar
, Síndrome de Down/complicações
, Humanos
, Dor Pós-Operatória/diagnóstico
, Dor Pós-Operatória/tratamento farmacológico
, Estudos Retrospectivos
RESUMO
The detrimental effects of tobacco exposure on children's health are well known. Nonetheless, the prevalence of secondhand or direct cigarette smoke exposure (CSE) in the pediatric population has not significantly decreased over time. On the contrary, the rapid incline in use of e-cigarettes among adolescents has evoked public health concerns since increasing cases of vaping-induced acute lung injury have highlighted the potential harm of these new "smoking" devices. Two pediatric populations are especially vulnerable to the detrimental effects of cigarette smoke. The first group is former premature infants whose risk is elevated both due to their prematurity as well as other risk factors such as oxygen and mechanical ventilation to which they are disproportionately exposed. The second group is children and adolescents with chronic respiratory diseases, in particular asthma and other wheezing disorders. Coronavirus disease 2019 (COVID-19) is a spectrum of diseases caused by infection with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that has spread worldwide over the last year. Here, respiratory symptoms ranging from mild to acute respiratory distress syndrome (ARDS) are at the forefront of COVID-19 cases among adults, and cigarette smoking is associated with worse outcomes in this population, and cigarette smoking is associated with worse outcomes in this population. Interestingly, SARS-CoV-2 infection affects children differently in regard to infection susceptibility, disease manifestations, and complications. Although children carry and transmit the virus, the likelihood of symptomatic infection is low, and the rates of hospitalization and death are even lower when compared to the adult population. However, multisystem inflammatory syndrome is recognized as a serious consequence of SARS-CoV-2 infection in the pediatric population. In addition, recent data demonstrate specific clinical patterns in children infected with SARS-CoV-2 who develop multisystem inflammatory syndrome vs. severe COVID-19. In this review, we highlight the pulmonary effects of CSE in vulnerable pediatric populations in the context of the ongoing SARS-CoV-2 pandemic.
RESUMO
OBJECTIVE: There are no data on the effect of X-Ray irradiation to the vulnerable pelvic organs of babies during DDH follow-up. This study aims to calculate, for the first time, the radiation exposure to infants during follow-up for DDH harness treatment, and thus quantify the lifetime risk of malignancy. METHODS: Patients who had completed 5 years' follow-up following successful Pavlik harness treatment were identified from the hospital DDH database. The radiation dose was extracted from the Computerised Radiology Information System database for every radiograph of every patient. The effective dose (ED) was calculated using conversion coefficients for age, sex and body region irradiated. Cumulative ED was compared to Health Protection Agency standards to calculate lifetime risk of malignancy from the radiographs. RESULTS: All radiographs of 40 infants, successfully treated in Pavlik harness for DDH, were assessed. The mean number of AP pelvis radiographs was 7.00 (range: 6-9, mode: 7). The mean cumulative ED was 0.25 mSv (Range: 0.11-0.46, SD: 0.07). This is far lower than the annual 'safe' limit for healthcare workers of 20 mSv and is categorised as "Very Low Risk". CONCLUSION: Clinicians involved in the treatment DDH can be re-assured that the cumulative radiation exposure from pelvic radiographs following Pavlik harness treatment is "Very Low Risk". Whilst being mindful of any radiation exposure in children, this study provides a scientific answer that help addresses parental concerns.
RESUMO
Reactive airway diseases are significant sources of pulmonary morbidity in neonatal and pediatric patients. Supplemental oxygen exposure in premature infants contributes to airway diseases such as asthma and promotes development of airway remodeling, characterized by increased airway smooth muscle (ASM) mass and extracellular matrix (ECM) deposition. Decreased plasma membrane caveolin-1 (CAV1) expression has been implicated in airway disease and may contribute to airway remodeling and hyperreactivity. Here, we investigated the impact of clinically relevant moderate hyperoxia (50% O2) on airway remodeling and caveolar protein expression in a neonatal mouse model. Within 12 h of birth, litters of B6129SF2J mice were randomized to room air (RA) or 50% hyperoxia exposure for 7 days with or without caveolin-1 scaffolding domain peptide (CSD; caveolin-1 mimic; 10 µl, 0.25 mM daily via intraperitoneal injection) followed by 14 days of recovery in normoxia. Moderate hyperoxia significantly increased airway reactivity and decreased pulmonary compliance at 3 wk. Histologic assessment demonstrated airway wall thickening and increased ASM mass following hyperoxia. RNA from isolated ASM demonstrated significant decreases in CAV1 and cavin-1 in hyperoxia-exposed animals while cavin-3 was increased. Supplementation with intraperitoneal CSD mitigated both the physiologic and histologic changes observed with hyperoxia. Overall, these data show that moderate hyperoxia is detrimental to developing airway and may predispose to airway reactivity and remodeling. Loss of CAV1 is one mechanism through which hyperoxia produces these deleterious effects. Supplementation of CAV1 using CSD or similar analogs may represent a new therapeutic avenue for blunting hyperoxia-induced pulmonary damage in neonates.
Assuntos
Anti-Inflamatórios/farmacologia , Hiper-Reatividade Brônquica/tratamento farmacológico , Caveolina 1/farmacologia , Hiperóxia/tratamento farmacológico , Pulmão/efeitos dos fármacos , Fragmentos de Peptídeos/farmacologia , Remodelação das Vias Aéreas/efeitos dos fármacos , Remodelação das Vias Aéreas/imunologia , Animais , Animais Recém-Nascidos , Hiper-Reatividade Brônquica/etiologia , Hiper-Reatividade Brônquica/genética , Hiper-Reatividade Brônquica/imunologia , Broncoconstritores/farmacologia , Caveolina 1/genética , Caveolina 1/imunologia , Modelos Animais de Doenças , Feminino , Regulação da Expressão Gênica , Humanos , Hiperóxia/etiologia , Hiperóxia/genética , Hiperóxia/imunologia , Injeções Intraperitoneais , Pulmão/imunologia , Pulmão/patologia , Masculino , Proteínas de Membrana/genética , Proteínas de Membrana/imunologia , Cloreto de Metacolina/farmacologia , Camundongos , Oxigênio/efeitos adversos , Proteínas de Ligação a RNA/genética , Proteínas de Ligação a RNA/imunologia , Transdução de SinaisRESUMO
BACKGROUND: Premature infants are at increased risk for airway diseases, such as wheezing and asthma, because of early exposure to risk factors including hyperoxia. As in adult asthma, airway remodeling and increased extracellular matrix (ECM) deposition is involved. METHODS: We assessed the impact of 24-72 h of moderate hyperoxia (50%) on human fetal airway smooth muscle (fASM) ECM deposition through western blot, modified in-cell western, and zymography techniques. RESULTS: Hyperoxia exposure significantly increased collagen I and collagen III deposition, increased pro- and cleaved matrix metalloproteinase 9 (MMP9) activity, and decreased endogenous MMP inhibitor, TIMP1, expression. Hyperoxia-induced change in caveolin-1 (CAV1) expression was assessed as a potential mechanism for the changes in ECM deposition. CAV1 expression was decreased following hyperoxia. Supplementation of CAV1 activity with caveolar scaffolding domain (CSD) peptide abrogated the hyperoxia-mediated ECM changes. CONCLUSION: These results demonstrate that moderate hyperoxia enhances ECM deposition in developing airways by altering the balance between MMPs and their inhibitors (TIMPs), and by increasing collagen deposition. These effects are partly mediated by a hyperoxia-induced decrease in CAV1 expression. In conjunction with prior data demonstrating increased fASM proliferation with hyperoxia, these data further demonstrate that hyperoxia is an important instigator of remodeling in developing airways.
Assuntos
Matriz Extracelular/metabolismo , Músculo Liso/citologia , Miócitos de Músculo Liso/efeitos dos fármacos , Sistema Respiratório/embriologia , Remodelação das Vias Aéreas , Asma/terapia , Caveolina 1/metabolismo , Hipóxia Celular , Proliferação de Células/efeitos dos fármacos , Células Cultivadas , Colágeno Tipo I/metabolismo , Proteínas da Matriz Extracelular/metabolismo , Humanos , Metaloproteinase 9 da Matriz/metabolismo , Fenótipo , RNA Interferente Pequeno/metabolismo , Sistema Respiratório/efeitos dos fármacos , Fatores de Risco , Transdução de Sinais , Fatores de Tempo , Inibidor Tecidual de Metaloproteinase-1/metabolismoRESUMO
BACKGROUND: Antenatal inflammation and preterm birth are associated with the development of airway diseases such as wheezing and asthma. Utilizing a newborn mouse model, we assessed the effects of maternal inflammation and postnatal hyperoxia on the neonatal airway. METHODS: Pregnant C57/Bl6 dams were injected with lipopolysaccharide (LPS) or saline on embryonic day 16. Offspring were placed in room air or hyperoxia (50% O2) for 7 d and then returned to normoxia. Airway mechanics, histology, and laser capture micro-dissection (LCM) were performed. RESULTS: At postnatal day 21, maternal LPS- and 50% O2-exposed pups exhibited increased resistance and decreased compliance compared to 21% O2 pups; however their effects were not synergistic. LPS and hyperoxia each increased the thickness of airway smooth muscle (ASM), but not the airway epithelial layer. Structural changes were largely limited to the conducting airways. Upregulation of inflammatory markers in the lung was observed at birth. LCM revealed increased collagen-3, transforming growth factor ß, and connective tissue growth factor expression with LPS and hyperoxia within the ASM layer. CONCLUSION: These novel studies provide functional, structural, and molecular evidence that antenatal inflammation is detrimental to the developing airway. Exposure to moderate hyperoxia does not exacerbate LPS effects on the airway.
Assuntos
Remodelação das Vias Aéreas , Hiperóxia/fisiopatologia , Inflamação/fisiopatologia , Lipopolissacarídeos/química , Sistema Respiratório/fisiopatologia , Animais , Animais Recém-Nascidos , Peso Corporal , Colágeno/química , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Elastina/química , Feminino , Pulmão/metabolismo , Cloreto de Metacolina/química , Camundongos , Camundongos Endogâmicos C57BL , Oxigênio/química , Gravidez , Prenhez , RespiraçãoRESUMO
Viral infections, such as respiratory syncytial virus and rhinovirus, adversely affect neonatal and pediatric populations, resulting in significant lung morbidity, including acute asthma exacerbation. Studies in adults have demonstrated that human airway smooth muscle (ASM) cells modulate inflammation through their ability to secrete inflammatory cytokines and chemokines. The role of ASM in the developing airway during infection remains undefined. In our study, we used human fetal ASM cells as an in vitro model to examine the effect of Toll-like receptor (TLR) agonists on chemokine secretion. We found that fetal ASM express multiple TLRs, including TLR3 and TLR4, which are implicated in the pathogenesis of respiratory syncytial virus and rhinovirus infection. Cells were treated with TLR agonists, polyinosinic-polycytidylic acid [poly(I:C)] (TLR3 agonist), lipopolysaccharide (TLR4 agonist), or R848 (TLR7/8 agonist), and IL-8 and chemokine (C-C motif) ligand 5 (CCL5) secretion were evaluated. Interestingly, poly(I:C), but neither lipopolysaccharide nor R848, increased IL-8 and chemokine (C-C motif) ligand 5 secretion. Examination of signaling pathways suggested that the poly(I:C) effects in fetal ASM involve TLR and ERK signaling, in addition to another major inflammatory pathway, NF-κB. Moreover, there are variations between fetal and adult ASM with respect to poly(I:C) effects on signaling pathways. Pharmacological inhibition suggested that ERK pathways mediate poly(I:C) effects. Overall, our data show that poly(I:C) initiates activation of proinflammatory pathways in developing ASM, which may contribute to immune responses to infection and exacerbation of asthma.
Assuntos
Quimiocinas/metabolismo , Pulmão/metabolismo , Miócitos de Músculo Liso/metabolismo , Receptor 3 Toll-Like/metabolismo , Células Cultivadas , Citocinas/metabolismo , Humanos , Lipopolissacarídeos/farmacologia , NF-kappa B/metabolismo , Transdução de Sinais/efeitos dos fármacosRESUMO
Exposure to moderate hyperoxia in prematurity contributes to subsequent airway dysfunction and increases the risk of developing recurrent wheeze and asthma. The nitric oxide (NO)-soluble guanylate cyclase (sGC)-cyclic GMP (cGMP) axis modulates airway tone by regulating airway smooth muscle (ASM) intracellular Ca(2+) ([Ca(2+)]i) and contractility. However, the effects of hyperoxia on this axis in the context of Ca(2+)/contractility are not known. In developing human ASM, we explored the effects of novel drugs that activate sGC independent of NO on alleviating hyperoxia (50% oxygen)-induced enhancement of Ca(2+) responses to bronchoconstrictor agonists. Treatment with BAY 41-2272 (sGC stimulator) and BAY 60-2770 (sGC activator) increased cGMP levels during exposure to 50% O2. Although 50% O2 did not alter sGCα1 or sGCß1 expression, BAY 60-2770 did increase sGCß1 expression. BAY 41-2272 and BAY 60-2770 blunted Ca(2+) responses to histamine in cells exposed to 50% O2. The effects of BAY 41-2272 and BAY 60-2770 were reversed by protein kinase G inhibition. These novel data demonstrate that BAY 41-2272 and BAY 60-2770 stimulate production of cGMP and blunt hyperoxia-induced increases in Ca(2+) responses in developing ASM. Accordingly, sGC stimulators/activators may be a useful therapeutic strategy in improving bronchodilation in preterm infants.
Assuntos
Benzoatos/farmacologia , Compostos de Bifenilo/farmacologia , Guanilato Ciclase/antagonistas & inibidores , Hidrocarbonetos Fluorados/farmacologia , Hiperóxia/tratamento farmacológico , Miócitos de Músculo Liso/metabolismo , Pirazóis/farmacologia , Piridinas/farmacologia , Receptores Citoplasmáticos e Nucleares/antagonistas & inibidores , Brônquios/patologia , Sinalização do Cálcio , Células Cultivadas , GMP Cíclico/metabolismo , Avaliação Pré-Clínica de Medicamentos , Guanilato Ciclase/metabolismo , Humanos , Hiperóxia/enzimologia , Músculo Liso/efeitos dos fármacos , Músculo Liso/embriologia , Músculo Liso/patologia , Miócitos de Músculo Liso/efeitos dos fármacos , Oxigênio/fisiologia , Receptores Citoplasmáticos e Nucleares/metabolismo , Guanilil Ciclase Solúvel , Traqueia/patologiaRESUMO
Lung diseases, such as bronchopulmonary dysplasia (BPD), wheezing, and asthma, remain significant causes of morbidity and mortality in the pediatric population, particularly in the setting of premature birth. Pulmonary outcomes in these infants are highly influenced by perinatal exposures including prenatal inflammation, postnatal intensive care unit interventions, and environmental agents. Here, there is strong evidence that perinatal supplemental oxygen administration has significant effects on pulmonary development and health. This is of particular importance in the preterm lung, where premature exposure to room air represents a hyperoxic insult that may cause harm to a lung primed to develop in a hypoxic environment. Preterm infants are also subject to increased episodes of hypoxia, which may also result in pulmonary damage and disease. Here, we summarize the current understanding of the effects of oxygen on the developing lung and how low vs. high oxygen may predispose to pulmonary disease that may extend even into adulthood. Better understanding of the underlying mechanisms will help lead to improved care and outcomes in this vulnerable population.
Assuntos
Pneumopatias/etiologia , Pulmão/crescimento & desenvolvimento , Oxigênio/efeitos adversos , Animais , Feminino , Humanos , Hiperóxia/metabolismo , Hipóxia/metabolismo , Recém-Nascido Prematuro , Inflamação/metabolismo , Pulmão/metabolismo , Pneumopatias/patologia , Lesão Pulmonar/metabolismo , Oxigênio/metabolismo , Gravidez , Fator A de Crescimento do Endotélio Vascular/metabolismoRESUMO
Asthma in the pediatric population remains a significant contributor to morbidity and increasing healthcare costs. Vitamin D3 insufficiency and deficiency have been associated with development of asthma. Recent studies in models of adult airway diseases suggest that the bioactive Vitamin D3 metabolite, calcitriol (1,25-dihydroxyvitamin D3 ; 1,25(OH)2 D3 ), modulates responses to inflammation; however, this concept has not been explored in developing airways in the context of pediatric asthma. We used human fetal airway smooth muscle (ASM) cells as a model of the early postnatal airway to explore how calcitriol modulates remodeling induced by pro-inflammatory cytokines. Cells were pre-treated with calcitriol and then exposed to TNFα or TGFß for up to 72 h. Matrix metalloproteinase (MMP) activity, production of extracellular matrix (ECM), and cell proliferation were assessed. Calcitriol attenuated TNFα enhancement of MMP-9 expression and activity. Additionally, calcitriol attenuated TNFα and TGFß-induced collagen III expression and deposition, and separately, inhibited proliferation of fetal ASM cells induced by either inflammatory mediator. Analysis of signaling pathways suggested that calcitriol effects in fetal ASM involve ERK signaling, but not other major inflammatory pathways. Overall, our data demonstrate that calcitriol can blunt multiple effects of TNFα and TGFß in developing airway, and point to a potentially novel approach to alleviating structural changes in inflammatory airway diseases of childhood.
Assuntos
Remodelação das Vias Aéreas/efeitos dos fármacos , Asma/metabolismo , Calcitriol/deficiência , Citocinas/metabolismo , Miócitos de Músculo Liso/metabolismo , Deficiência de Vitamina D/metabolismo , Proliferação de Células/efeitos dos fármacos , Matriz Extracelular/metabolismo , Humanos , Músculo Liso/metabolismo , Fator de Necrose Tumoral alfa/metabolismoRESUMO
Cigarette smoke is a common environmental insult associated with increased risk of developing airway diseases such as wheezing and asthma in neonates and children. In adults, asthma involves airway remodeling characterized by increased airway smooth muscle (ASM) cell proliferation and increased extracellular matrix (ECM) deposition, as well as airway hyperreactivity. The effects of cigarette smoke on remodeling and contractility in the developing airway are not well-elucidated. In this study, we used canalicular-stage (18-20 wk gestational age) human fetal airway smooth muscle (fASM) cells as an in vitro model of the immature airway. fASM cells were exposed to cigarette smoke extract (CSE; 0.5-1.5% for 24-72 h), and cell proliferation, ECM deposition, and intracellular calcium ([Ca(2+)]i) responses to agonist (histamine 10 µM) were used to evaluate effects on remodeling and hyperreactivity. CSE significantly increased cell proliferation and deposition of ECM molecules collagen I, collagen III, and fibronectin. In contrast, [Ca(2+)]i responses were not significantly affected by CSE. Analysis of key signaling pathways demonstrated significant increase in extracellular signal-related kinase (ERK) and p38 activation with CSE. Inhibition of ERK or p38 signaling prevented CSE-mediated changes in proliferation, whereas only ERK inhibition attenuated the CSE-mediated increase in ECM deposition. Overall, these results demonstrate that cigarette smoke may enhance remodeling in developing human ASM through hyperplasia and ECM production, thus contributing to development of neonatal and pediatric airway disease.
Assuntos
Proliferação de Células , Matriz Extracelular/metabolismo , Modelos Biológicos , Músculo Liso/metabolismo , Sistema Respiratório/metabolismo , Fumar/metabolismo , Cálcio/metabolismo , Sinalização do Cálcio , Colágeno Tipo I/biossíntese , Colágeno Tipo III/biossíntese , Matriz Extracelular/patologia , Feto/metabolismo , Feto/patologia , Humanos , Sistema de Sinalização das MAP Quinases , Músculo Liso/patologia , Sistema Respiratório/patologia , Fumar/efeitos adversos , Fumar/patologia , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismoRESUMO
Wheezing and asthma are significant clinical problems for infants and young children, particularly following premature birth. Recurrent wheezing in infants can progress to persistent asthma. As in adults, altered airway structure (remodeling) and function (increased bronchoconstriction) are also important in neonatal and pediatric airway diseases. Accumulating evidence suggests that airway disease in children is influenced by perinatal factors including perturbations in normal fetal lung development, postnatal interventions in the intensive care unit (ICU) and environmental and other insults in the neonatal period. Here, in addition to genetics, maternal health, environmental processes, innate immunity and impaired lung development/function can all influence pathogenesis of airway disease in children. We summarize current understanding of how prenatal and postnatal factors can contribute to development of airway diseases in neonates and children. Understanding these mechanisms will help identify and develop novel therapies for childhood airway diseases.