RESUMEN

Acute lung injury (ALI) is a common clinical syndrome, which often results in pulmonary edema and respiratory distress. It has been recently reported that phosphatidylethanolamine binding protein 4 (PEBP4), a basic cytoplasmic protein, has anti-inflammatory and hepatoprotective effects, but its relationship with ALI remains undefined so far. In this study, we generated PEBP4 knockout (KO) mice to investigate the potential function of PEBP4, as well as to evaluate the capacity of alveolar fluid clearance (AFC) and the activity of phosphatidylinositide 3-kinases (PI3K)/serine-theronine protein kinase B (PKB, also known as AKT) signaling pathway in lipopolysaccharide (LPS)-induced ALI mice models. We found that PEBP4 deficiency exacerbated lung pathological damage and edema, and increased the wet/dry weight ratio and total protein concentration of bronchoalveolar lavage fluid (BALF) in LPS-treated mice. Meanwhile, PEBP4 KO promoted an LPS-induced rise in the pulmonary myeloperoxidase (MPO) activity, serum interleuin (IL)-1ß, IL-6, and tumor necrosis factor (TNF)-α levels, and pulmonary cyclooxygenase-2 (COX-2) expression. Mechanically, PEBP4 deletion further reduced the protein expression of Na+ transport markers, including epithelial sodium channel (ENaC)-α, ENaC-γ, Na,K-ATPase α1, and Na,K-ATPase ß1, and strengthened the inhibition of PI3K/AKT signaling in LPS-challenged mice. Furthermore, we demonstrated that selective activation of PI3K/AKT with 740YP or SC79 partially reversed all of the above effects caused by PEBP4 KO in LPS-treated mice. Altogether, our results indicated the PEBP4 deletion has a deterioration effect on LPS-induced ALI by impairing the capacity of AFC, which may be achieved through modulating the PI3K/AKT pathway.

Asunto(s)

Lesión Pulmonar Aguda , Lipopolisacáridos , Animales , Ratones , Lesión Pulmonar Aguda/inducido químicamente , Lipopolisacáridos/farmacología , Pulmón/metabolismo , Fosfatidilinositol 3-Quinasas/metabolismo , Proteínas Proto-Oncogénicas c-akt/metabolismo , Transducción de Señal , ATPasa Intercambiadora de Sodio-Potasio/metabolismo , ATPasa Intercambiadora de Sodio-Potasio/farmacología , ATPasa Intercambiadora de Sodio-Potasio/uso terapéutico , Factor de Necrosis Tumoral alfa/metabolismo

RESUMEN

Sepsis-induced acute respiratory distress syndrome (ARDS) causes significant fatalities worldwide and lacks pharmacological intervention. Alveolar fluid clearance (AFC) plays a pivotal role in the remission of ARDS and is markedly impaired in the pathogenesis of ARDS. Here, we demonstrated that erythropoietin could effectively ameliorate lung injury manifestations and lethality, restore lung function and promote AFC in a rat model of lipopolysaccharide (LPS)-induced ARDS. Moreover, it was proven that EPO-induced restoration of AFC occurs through triggering the total protein expression of ENaC and Na,K-ATPase channels, enhancing their protein abundance in the membrane, and suppressing their ubiquitination for degeneration. Mechanistically, the data indicated the possible involvement of EPOR/JAK2/STAT3/SGK1/Nedd4-2 signaling in this process, and the pharmacological inhibition of the pathway markedly eliminated the stimulating effects of EPO on ENaC and Na,K-ATPase, and subsequently reversed the augmentation of AFC by EPO. Consistently, in vitro studies of alveolar epithelial cells paralleled with that EPO upregulated the expression of ENaC and Na,K-ATPase, and patch-clamp studies further demonstrated that EPO substantially strengthened sodium ion currents. Collectively, EPO could effectively promote AFC by improving ENaC and Na,K-ATPase protein expression and abundance in the membrane, dependent on inhibition of ENaC and Na,K-ATPase ubiquitination, and resulting in diminishing LPS-associated lung injuries.

Asunto(s)

Canales Epiteliales de Sodio , Eritropoyetina , Ratas Sprague-Dawley , Síndrome de Dificultad Respiratoria , Sepsis , ATPasa Intercambiadora de Sodio-Potasio , Ubiquitinación , Animales , Canales Epiteliales de Sodio/metabolismo , ATPasa Intercambiadora de Sodio-Potasio/metabolismo , Eritropoyetina/farmacología , Sepsis/complicaciones , Sepsis/tratamiento farmacológico , Sepsis/metabolismo , Ubiquitinación/efectos de los fármacos , Síndrome de Dificultad Respiratoria/tratamiento farmacológico , Síndrome de Dificultad Respiratoria/metabolismo , Masculino , Ratas , Alveolos Pulmonares/efectos de los fármacos , Alveolos Pulmonares/metabolismo , Alveolos Pulmonares/patología , Lipopolisacáridos , Transducción de Señal/efectos de los fármacos , Modelos Animales de Enfermedad

RESUMEN

Acute lung injury (ALI) is a common lung disease with increasing morbidity and mortality rates due to the lack of specific drugs. Impaired alveolar fluid clearance (AFC) is a primary pathological feature of ALI. Epithelial sodium channel (ENaC) is a primary determinant in regulating the transport of Na+ and the clearance of alveolar edema fluid. Therefore, ENaC is an important target for the development of drugs for ALI therapy. However, the role of ENaC in the progression of ALI remains unclear. Inhibition of early growth response factor (EGR-1) expression has been reported to induce a protective effect on ALI; therefore, we evaluated whether EGR-1 participates in the progression of ALI by regulating ENaC-α in alveolar epithelium. We investigated the potential mechanism of EGR-1-mediated regulation of ENaC in ALI. We investigated whether EGR-1 aggravates the pulmonary edema response in ALI by regulating ENaC. ALI mouse models were established by intrabronchial injection of lipopolysaccharides (LPS). Lentiviruses with EGR-1 knockdown were transfected into LPS-stimulated A549 cells. We found that EGR-1 expression was upregulated in the lung tissues of ALI mice and in LPS-induced A549 cells, and was negatively correlated with ENaC-α expression. Knockdown of EGR-1 increased ENaC-α expression and relieved cellular edema in ALI. Moreover, EGR-1 regulated ENaC-α expression at the transcriptional level, and correspondingly promoted pulmonary edema and aggravated ALI symptoms. In conclusion, our study demonstrated that EGR-1 could promote pulmonary edema by downregulating ENaC-α at the transcriptional level in ALI. Our study provides a new potential therapeutic strategy for treatment of ALI.

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EGR-1 expression was increased in LPS-induced ALI mice and associated with aggravated pulmonary edemaEGR-1 induced pulmonary edema relying on regulating the expression of ENaC-α at the transcriptional level by manipulating the promoter.

Asunto(s)

Lesión Pulmonar Aguda , Edema Pulmonar , Animales , Humanos , Ratones , Células A549 , Lesión Pulmonar Aguda/inducido químicamente , Canales Epiteliales de Sodio/genética , Lipopolisacáridos

RESUMEN

Impaired alveolar fluid clearance (AFC) is an important cause of alveolar edema fluid accumulation in patients with acute respiratory distress syndrome (ARDS). Alveolar edema leads to insufficient gas exchange and worse clinical outcomes. Thus, it is important to understand the pathophysiology of impaired AFC in order to develop new therapies for ARDS. Over the last few decades, multiple experimental studies have been done to understand the molecular, cellular, and physiological mechanisms that regulate AFC in the normal and the injured lung. This review provides a review of AFC in the normal lung, focuses on the mechanisms of impaired AFC, and then outlines the regulation of AFC. Finally, we summarize ongoing challenges and possible future research that may offer promising therapies for ARDS.

RESUMEN

@#Abstract: Objective　To explore the correlation between levels of hypersensitive C-reactive protein (hs-CRP) and procalcitonin (PCT) in serum and alveolar fluid and severity of disease in children with lobar pneumonia. Methods　A total of 112 children diagnosed with lobar pneumonia from September 2020 to September 2021 were selected as the research subjects. The levels of hs-CRP and PCT in serum and alveolar fluid were detected by double antibody sandwich enzyme-linked immunosorbent assay (ELISA). The children were divided into severe group (clinical pulmonary infection score, CPIS≥6 points) and mild group (CPIS<6 points) according to the severity of disease, and further classified into good prognosis group (cured, improved) and poor prognosis group (uncured) according to their treatment outcomes. The correlation of levels of hs-CRP and PCT in serum and alveolar fluid with disease severity in children and their predictive value on prognosis were analyzed. Results　The levels of serum hs-CRP and PCT in severe group were (17.73±3.26) μg/L and (8.59±1.84) μg/L, which were significantly higher than corresponding (12.58±3.09) μg/L, and (5.62±1.59) μg/L in mild group (P<0.05); the levels of hs-CRP and PCT in alveolar fluid in severe group were (21.25±4.18) μg/L and (8.71±1.54) μg/L, which were significantly higher than corresponding (13.79±2.76) μg/L and (5.38±1.69) μg/L in mild group (P<0.05). The levels of hs-CRP and PCT in serum and alveolar fluid were positively correlated with CPIS scores (r=0.398, 0.441; 0.475, 0.586, P<0.05). The levels of hs-CRP and PCT in serum in poor prognosis group were (20.09±4.20) μg/L and (13.35±2.91) μg/L, which were significantly higher corresponding (8.75±2.19) μg/L and (6.28±1.31) μg/L in good prognosis group (P<0.05). The levels of hs-CRP and PCT in alveolar fluid were (23.70±4.29) μg/L and (10.73±2.04) μg/L, which were higher than corresponding (15.08±3.56) μg/L and (5.79±1.10) μg/L in poor prognosis group (P<0.05). There was no significant difference in AUC between combined detection of serum indicators and combined detection of alveolar perfusion fluid indicators in predicting the prognosis of children with lobar pneumonia (P>0.05). Conclusions　The levels of hs-CRP and PCT in serum and alveolar fluid of children with lobar pneumonia are significantly increased and positively correlated with the severity of disease. However, the predictive value of the combined detection of serum indicators and combined detection of alveolar perfusion fluid indicators for the prognosis of children with lobar pneumonia is comparable.

RESUMEN

Acute lung injury ( ALI) and its most extreme form a-cute respiratory distress syndrome ( ARDS) are lung diseases with high morbidity and mortality. There is no effective therapeutic intervention until now for its complicated pathophysiologi-cal processes and sophisticated regulatory mechanism. Histone deacetylases (HDACs) are a family of proteins with deacetylase activity. Studies have shown that HDACs are involved in the pathophysiological processes of ALI/ARDS, including inflammatory responses,endothelial permeability,oxidative stresses,alveolar fluid clearance and lung tissue repairment. Simultaneously, the use of HDACs inhibitors (HDACIs) can interfere with ALI/ ARDS progression. In this review we describe and summarize the pathophysiological processes and the underlying mechanisms in ALI/ARDS regulated by HDACs and HDACIs in detail, in order to provide the basis for the clinical application of HDACs-targe- ted agents and indicate directions for future study.

RESUMEN

Alumina nanoparticles (Al2O3 NPs) can be released in occupational environments in different contexts such as industry, defense, and aerospace. Workers can be exposed by inhalation to these NPs, for instance, through welding fumes or aerosolized propellant combustion residues. Several clinical and epidemiological studies have reported that inhalation of Al2O3 NPs could trigger aluminosis, inflammation in the lung parenchyma, respiratory symptoms such as cough or shortness of breath, and probably long-term pulmonary fibrosis. The present review is a critical update of the current knowledge on underlying toxicological, molecular, and cellular mechanisms induced by exposure to Al2O3 NPs in the lungs. A major part of animal studies also points out inflammatory cells and secreted biomarkers in broncho-alveolar lavage fluid (BALF) and blood serum, while in vitro studies on lung cells indicate contradictory results regarding the toxicity of these NPs.

RESUMEN

Tumor necrosis factor (TNF) is a homotrimer that has two spatially distinct binding regions, three lectin-like domains (LLD) at the TIP of the protein and three basolaterally located receptor-binding sites, the latter of which are responsible for the inflammatory and cell death-inducing properties of the cytokine. Solnatide (a.k.a. TIP peptide, AP301) is a 17-mer cyclic peptide that mimics the LLD of human TNF which activates the amiloride-sensitive epithelial sodium channel (ENaC) and, as such, recapitulates the capacity of TNF to enhance alveolar fluid clearance, as demonstrated in numerous preclinical studies. TNF and solnatide interact with glycoproteins and these interactions are necessary for their trypanolytic and ENaC-activating activities. In view of the crucial role of ENaC in lung liquid clearance, solnatide is currently being evaluated as a novel therapeutic agent to treat pulmonary edema in patients with moderate-to-severe acute respiratory distress syndrome (ARDS), as well as severe COVID-19 patients with ARDS. To facilitate the description of the functional properties of solnatide in detail, as well as to further target-docking studies, we have analyzed its folding properties by NMR. In solution, solnatide populates a set of conformations characterized by a small hydrophobic core and two electrostatically charged poles. Using the structural information determined here and also that available for the ENaC protein, we propose a model to describe solnatide interaction with the C-terminal domain of the ENaCα subunit. This model may serve to guide future experiments to validate specific interactions with ENaCα and the design of new solnatide analogs with unexplored functionalities.

RESUMEN

In order to effectively treat the infection of Streptococcus suis and reduce the emergence of drug-resistant bacteria, an aditoprim (ADP) injection was developed in this study. The pharmaceutical property investigation results demonstrated that ADP injection was a clear yellow liquid with 10 g ADP distributing in every 100 mL solution uniformly. Its pH value and drug content were around 6.20 and 99.35~100.40%, respectively. And quality assessment preliminarily indicated its reliable quality and stability. Additionally, the bronchoalveolar lavage fluid method was first applied to evaluate accurate ADP concentration at infection site in this study. Through pharmacodynamic assay, the MIC, MBC and MPC of ADP against Streptococcus suis CVCC 607 was 2 µg/mL, 4 µg/mL and 12.8 µg/mL, respectively. The bacteria growth inhibition curves showed that ADP was a concentration-dependent antibacterial drug, and the PK-PD model parameter of AUC/MIC was selected. The pharmacokinetic parameters of alveolar fluid evaluated by WinNonlin software revealed similar pharmacokinetic process of ADP in healthy pigs and infected pigs. Combined with pharmacokinetics-pharmacodynamics (PK-PD) modeling, the dosage regimen of 3~5 days with an interval of 12 h at 4.10 mg/kg or 5.91 mg/kg could be adopted to treat the infection of Streptococcus suis. Consequently, this ADP injection with a multi-dose protocol would be a promising antimicrobial product for efficient treatment of S. suis infection of pigs.

RESUMEN

Coronaviruses are highly pathogenic and transmissible viruses. The SARS-CoV-2 virus that emerged in December 2019 is increasingly recognized as a serious, worldwide public health concern. Respiratory infections and the hyper-inflammatory response induced by SARS-CoV-2 play a key role in disease severity and death in infected COVID-19 patients. However, much uncertainty still exists about the pathogenesis and various effects of COVID-19 on immune system. It seems that memory T cells can reduce the severity of COVID-19 infection by inducing a protective immune response. Memory T cells along with protective antibodies are the main defenses and also protective barrier against recurrent COVID-19 infection. The role of Memory T cells varies in different ages and the severity of COVID-19 infection varies between children, adults and the elderly. Furthermore, the aim of this review is to evaluate the role of memory cells in mild, moderate and severe infected COVID-19 patients with different ages.

RESUMEN

ETHNOPHARMACOLOGICAL RELEVANCE: Luteolin (Lut) was recently identified as the major active ingredient of Mosla scabra, which was a typical representative traditional Chinese medicine and had been used to treat pulmonary diseases for thousands of years. AIM OF THE STUDY: This study was to explore the effects and relative mechanisms of Lut in LPS-induced acute lung injury/acute respiratory distress syndrome (ALI/ARDS). The main characteristic of ALI/ARDS is pulmonary edema, and epithelial sodium channel (ENaC) is a key factor in effective removal of excessive alveolar edematous fluid, which is essential for repairing gas exchange and minimizing damage to the peripheral tissues. However, whether the therapeutic effects of Lut on respiratory diseases are relative with ENaC is still unknown. MATERIALS AND METHODS: Alveolar fluid clearance was calculated in BALB/c mice and ENaC function was measured in H441 cells. Moreover, ENaC membrane protein and mRNA were detected by Western blot and real-time PCR, respectively. We also studied the involvement of cGMP/PI3K pathway during the regulation of Lut on ENaC during LPS-induced ALI/ARDS by ELISA method and applying cGMP/PI3K inhibitors/siRNA. RESULTS: The beneficial effects of Lut in ALI/ARDS were evidenced by the alleviation of pulmonary edema, and enhancement of both amiloride-sensitive alveolar fluid clearance and short-circuit currents. Lut could alleviate the LPS decreased expression levels of ENaC mRNA and membrane protein in H441 cells and mouse lung. In addition, cGMP concentration was increased after the administration of Lut in ALI/ARDS mice, while the inhibition of cGMP/PI3K pathway could abrogate the enhanced AFC and ENaC protein expression of Lut. CONCLUSION: These results implied that Lut could attenuate pulmonary edema via enhancing the abundance of membrane ENaC at least partially through the cGMP/PI3K pathway, which could provide a promising therapeutic strategy for treating ALI/ARDS.

Asunto(s)

Células Epiteliales Alveolares/efectos de los fármacos , Lipopolisacáridos/toxicidad , Lesión Pulmonar/tratamiento farmacológico , Luteolina/uso terapéutico , Síndrome de Dificultad Respiratoria/tratamiento farmacológico , Canales de Sodio/metabolismo , Animales , Cromonas/farmacología , GMP Cíclico/antagonistas & inhibidores , GMP Cíclico/genética , GMP Cíclico/metabolismo , Regulación de la Expresión Génica/efectos de los fármacos , Lesión Pulmonar/inducido químicamente , Masculino , Ratones , Ratones Endogámicos BALB C , Morfolinas/farmacología , Fosfatidilinositol 3-Quinasas/genética , Fosfatidilinositol 3-Quinasas/metabolismo , Distribución Aleatoria , Síndrome de Dificultad Respiratoria/inducido químicamente , Regulación hacia Arriba/efectos de los fármacos

RESUMEN

Background: Ventilator-induced lung injury (VILI) is characterized by vascular barrier dysfunction and suppression of alveolar fluid clearance (AFC). Obesity itself leads to chronic inflammation, which may initiate an injurious cascade to the lungs and simultaneously induce a protective feedback. In this study, we investigated the protective mechanism of obesity on VILI in a mouse model. Methods: The VILI model was set up via 6-h mechanical ventilation with a high tidal volume. Parameters including lung injury score, STAT3/NFκB pathway, and AFC were assessed. Mice with diet-induced obesity were obtained by allowing free access to a high-fat diet since the age of 3 weeks. After a 9-week diet intervention, these mice were sacrificed at the age of 12 weeks. The manipulation of SOCS3 protein was achieved by siRNA knockdown and pharmaceutical stimulation using hesperetin. WNK4 knockin and knockout obese mice were used to clarify the pathway of AFC modulation. Results: Obesity itself attenuated VILI. Knockdown of SOCS3 in obese mice offset the protection against VILI afforded by obesity. Hesperetin stimulated SOCS3 upregulation in nonobese mice and provided protection against VILI. In obese mice, the WNK4 axis was upregulated at the baseline, but was significantly attenuated after VILI compared with nonobese mice. At the baseline, the manipulation of SOCS3 by siRNA and hesperetin also led to the corresponding alteration of WNK4, albeit to a lesser extent. After VILI, WNK4 expression correlated with STAT3/NFκB activation, regardless of SOCS3 status. Obese mice carrying WNK4 knockout had VILI with a severity similar to that of wild-type obese mice. The severity of VILI in WNK4-knockin obese mice was counteracted by obesity, similar to that of wild-type nonobese mice only. Conclusions: Obesity protects lungs from VILI by upregulating SOCS3, thus suppressing the STAT3/NFκB inflammatory pathway and enhancing WNK4-related AFC. However, WNK4 activation is mainly from direct NFκB downstreaming, and less from SOCS3 upregulation. Moreover, JAK2-STAT3/NFκB signaling predominates the pathogenesis of VILI. Nevertheless, the interaction between SOCS3 and WNK4 in modulating VILI in obesity warrants further investigation.

Asunto(s)

Obesidad/complicaciones , Factor de Transcripción STAT3/metabolismo , Transducción de Señal , Proteína 3 Supresora de la Señalización de Citocinas/metabolismo , Lesión Pulmonar Inducida por Ventilación Mecánica/complicaciones , Lesión Pulmonar Inducida por Ventilación Mecánica/metabolismo , Animales , Biomarcadores , Citocinas/metabolismo , Dieta Alta en Grasa , Modelos Animales de Enfermedad , Progresión de la Enfermedad , Susceptibilidad a Enfermedades , Regulación de la Expresión Génica , Técnicas de Silenciamiento del Gen , Ratones , Ratones Noqueados , FN-kappa B/metabolismo , Proteínas Serina-Treonina Quinasas/metabolismo , Interferencia de ARN , Proteína 3 Supresora de la Señalización de Citocinas/genética , Lesión Pulmonar Inducida por Ventilación Mecánica/etiología

RESUMEN

We previously reported that extracellular vesicles (EVs) released during Escherichia coli (E. coli) bacterial pneumonia were inflammatory, and administration of high molecular weight hyaluronic acid (HMW HA) suppressed several indices of acute lung injury (ALI) from E. coli pneumonia by binding to these inflammatory EVs. The current study was undertaken to study the therapeutic effects of HMW HA in ex vivo perfused human lungs injured with Pseudomonas aeruginosa (PA)103 bacterial pneumonia. For lungs with baseline alveolar fluid clearance (AFC) <10%/h, HMW HA 1 or 2 mg was injected intravenously after 1 h (n = 4-9), and EVs released during PA pneumonia were collected from the perfusate over 6 h. For lungs with baseline AFC > 10%/h, HMW HA 2 mg was injected intravenously after 1 h (n = 6). In vitro experiments were conducted to evaluate the effects of HA on inflammation and bacterial phagocytosis. For lungs with AFC < 10%/h, administration of HMW HA intravenously significantly restored AFC and numerically decreased protein permeability and alveolar inflammation from PA103 pneumonia but had no effect on bacterial counts at 6 h. However, HMW HA improved bacterial phagocytosis by human monocytes and neutrophils and suppressed the inflammatory properties of EVs released during pneumonia on monocytes. For lungs with AFC > 10%/h, administration of HMW HA intravenously improved AFC from PA103 pneumonia but had no significant effects on protein permeability, inflammation, or bacterial counts. In the presence of impaired alveolar epithelial transport capacity, administration of HMW HA improved the resolution of pulmonary edema from Pseudomonas PA103 bacterial pneumonia.

Asunto(s)

Lesión Pulmonar Aguda/tratamiento farmacológico , Ácido Hialurónico/farmacología , Neumonía Bacteriana/tratamiento farmacológico , Infecciones por Pseudomonas/tratamiento farmacológico , Pseudomonas aeruginosa/efectos de los fármacos , Edema Pulmonar/tratamiento farmacológico , Lesión Pulmonar Aguda/microbiología , Lesión Pulmonar Aguda/patología , Adulto , Vesículas Extracelulares/patología , Femenino , Humanos , Pulmón/efectos de los fármacos , Pulmón/microbiología , Pulmón/patología , Masculino , Persona de Mediana Edad , Monocitos/inmunología , Neutrófilos/inmunología , Técnicas de Cultivo de Órganos , Fagocitosis/efectos de los fármacos , Neumonía Bacteriana/microbiología , Neumonía Bacteriana/patología , Edema Pulmonar/microbiología , Edema Pulmonar/patología , Síndrome de Dificultad Respiratoria/tratamiento farmacológico , Síndrome de Dificultad Respiratoria/microbiología , Síndrome de Dificultad Respiratoria/patología

RESUMEN

Chronic alcohol abuse increases the risk of mortality and poor outcomes in patients with acute respiratory distress syndrome. However, the underlying mechanisms remain to be elucidated. The present study aimed to investigate the effects of chronic alcohol consumption on lung injury and clarify the signaling pathways involved in the inhibition of alveolar fluid clearance (AFC). In order to produce rodent models with chronic alcohol consumption, wild­type C57BL/6 mice were treated with alcohol. A2a adenosine receptor (AR) small interfering (si)RNA or A2bAR siRNA were transfected into the lung tissue of mice and primary rat alveolar type II (ATII) cells. The rate of AFC in lung tissue was measured during exposure to lipopolysaccharide (LPS). Epithelial sodium channel (ENaC) expression was determined to investigate the mechanisms underlying alcohol­induced regulation of AFC. In the present study, exposure to alcohol reduced AFC, exacerbated pulmonary edema and worsened LPS­induced lung injury. Alcohol caused a decrease in cyclic adenosine monophosphate (cAMP) levels and inhibited α­ENaC, ß­ENaC and γ­ENaC expression levels in the lung tissue of mice and ATII cells. Furthermore, alcohol decreased α­ENaC, ß­ENaC and γ­ENaC expression levels via the A2aAR or A2bAR­cAMP signaling pathways in vitro. In conclusion, the results of the present study demonstrated that chronic alcohol consumption worsened lung injury by aggravating pulmonary edema and impairing AFC. An alcohol­induced decrease of α­ENaC, ß­ENaC and γ­ENaC expression levels by the A2AR­mediated cAMP pathway may be responsible for the exacerbated effects of chronic alcohol consumption in lung injury.

Asunto(s)

Lesión Pulmonar Aguda/metabolismo , Células Epiteliales Alveolares/metabolismo , Canales Epiteliales de Sodio/efectos de los fármacos , Canales Epiteliales de Sodio/metabolismo , Etanol/farmacología , Receptores de Adenosina A2/metabolismo , Lesión Pulmonar Aguda/inducido químicamente , Lesión Pulmonar Aguda/patología , Células Epiteliales Alveolares/patología , Animales , AMP Cíclico/metabolismo , Citocinas , Lipopolisacáridos/efectos adversos , Pulmón/metabolismo , Lesión Pulmonar/inducido químicamente , Lesión Pulmonar/metabolismo , Lesión Pulmonar/patología , Ratones , Ratones Endogámicos C57BL , Alveolos Pulmonares/metabolismo , Edema Pulmonar/inducido químicamente , Edema Pulmonar/metabolismo , Edema Pulmonar/patología , Factores de Empalme de ARN/genética , Factores de Empalme de ARN/metabolismo , Ratas , Receptor de Adenosina A2A/genética , Receptor de Adenosina A2A/metabolismo , Transducción de Señal

RESUMEN

Prolonged oxygen therapy leads to oxidative stress, epithelial dysfunction, and acute lung injury in preterm infants and adults. Heterozygous Scnn1b mice, which overexpress lung epithelial sodium channels (ENaC), and their wild-type (WT) C57Bl6 littermates were utilized to study the pathogenesis of high fraction inspired oxygen ([Formula: see text])-induced lung injury. Exposure to high [Formula: see text] from birth to postnatal (PN) day 11 was used to model oxidative stress. Chronic exposure of newborn pups to 85% O2 increased glutathione disulfide (GSSG) and elevated the GSH/GSSG redox potential (Eh) of bronchoalveolar lavage fluid (BALF). Longitudinal X-ray imaging and Evans blue-labeled-albumin assays showed that chronic 85% O2 and acute GSSG (400 µM) exposures decreased alveolar fluid clearance (AFC) in the WT lung. Morphometric analysis of WT pups insufflated with GSSG (400 µM) or amiloride (1 µM) showed a reduction in alveologenesis and increased lung injury compared with age-matched control pups. The Scnn1b mouse lung phenotype was not further aggravated by chronic 85% O2 exposure. These outcomes support the hypothesis that exposure to hyperoxia increases GSSG, resulting in reduced lung fluid reabsorption due to inhibition of amiloride-sensitive ENaC. Flavin adenine dinucleotide (FADH2; 10 µM) was effective in recycling GSSG in vivo and promoted alveologenesis, but did not impact AFC nor attenuate fibrosis following high [Formula: see text] exposure. In conclusion, the data indicate that FADH2 may be pivotal for normal lung development, and show that ENaC is a key factor in promoting alveologenesis, sustaining AFC, and attenuating fibrotic lung injury caused by prolonged oxygen therapy in WT mice.

Asunto(s)

Lesión Pulmonar Aguda , Canales Epiteliales de Sodio , Oxígeno , Animales , Femenino , Masculino , Ratones , Lesión Pulmonar Aguda/etiología , Lesión Pulmonar Aguda/metabolismo , Lesión Pulmonar Aguda/patología , Lesión Pulmonar Aguda/prevención & control , Amilorida/toxicidad , Bloqueadores del Canal de Sodio Epitelial/toxicidad , Canales Epiteliales de Sodio/genética , Canales Epiteliales de Sodio/metabolismo , Disulfuro de Glutatión/toxicidad , Ratones Endogámicos C57BL , Oxígeno/toxicidad

RESUMEN

BACKGROUND: Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) are devastating clinical conditions characterized by pulmonary epithelial damage and protein-rich fluid accumulation in the alveolar spaces. Statins are a class of HMG-CoA reductase inhibitors, which exert cholesterol-lowering and anti-inflammatory effects. METHODS: Rosuvastatin (1 mg/kg) was injected intravenously in rats 12 h before lipopolysaccharide (LPS, 10 mg/kg) administration. Eight hours later after LPS challenge, alveolar fluid clearance (AFC) was detected in rats (n = 6-8). Rosuvastatin (0.3 µmol/mL) and LPS were cultured with primary rat alveolar type II epithelial cells for 8 h. RESULTS: Rosuvastatin obviously improved AFC and attenuated lung-tissue damage in ALI model. Moreover, it enhanced AFC by increasing sodium channel and Na,K-ATPase protein expression. It also up-regulated P-Akt via reducing Nedd4-2 in vivo and in vitro. Furthermore, LY294002 blocked the increase in AFC in response to rosuvastatin. Rosuvastatin-induced AFC was found to be partly rely on sodium channel and Na,K-ATPase expression via the PI3K/AKT/Nedd4-2 pathway. CONCLUSION: In summary, the findings of our study revealed the potential role of rosuvastatin in the management of ALI/ARDS.

RESUMEN

A significant number of patients with coronavirus disease 2019 (COVID-19) develop acute respiratory distress syndrome (ARDS) that is associated with a poor outcome. The molecular mechanisms driving failure of the alveolar barrier upon severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection remain incompletely understood. The Na,K-ATPase is an adhesion molecule and a plasma membrane transporter that is critically required for proper alveolar epithelial function by both promoting barrier integrity and resolution of excess alveolar fluid, thus enabling appropriate gas exchange. However, numerous SARS-CoV-2-mediated and COVID-19-related signals directly or indirectly impair the function of the Na,K-ATPase, thereby potentially contributing to disease progression. In this Perspective, we highlight some of the putative mechanisms of SARS-CoV-2-driven dysfunction of the Na,K-ATPase, focusing on expression, maturation, and trafficking of the transporter. A therapeutic mean to selectively inhibit the maladaptive signals that impair the Na,K-ATPase upon SARS-CoV-2 infection might be effective in reestablishing the alveolar epithelial barrier and promoting alveolar fluid clearance and thus advantageous in patients with COVID-19-associated ARDS.

Asunto(s)

COVID-19/patología , Alveolos Pulmonares/patología , Síndrome Respiratorio Agudo Grave/patología , ATPasa Intercambiadora de Sodio-Potasio/metabolismo , Uniones Estrechas/patología , Transporte Biológico/fisiología , Humanos , Edema Pulmonar/patología , SARS-CoV-2

RESUMEN

The constant transport of ions across the alveolar epithelial barrier regulates alveolar fluid homeostasis. Dysregulation or inhibition of Na+ transport causes fluid accumulation in the distal airspaces resulting in impaired gas exchange and respiratory failure. Previous studies have primarily focused on the critical role of amiloride-sensitive epithelial sodium channel (ENaC) in alveolar fluid clearance (AFC), yet activation of ENaC failed to attenuate pulmonary edema in clinical trials. Since 40% of AFC is amiloride-insensitive, Na+ channels/transporters other than ENaC such as Na+-coupled neutral amino acid transporters (SNATs) may provide novel therapeutic targets. Here, we identified a key role for SNAT2 (SLC38A2) in AFC and pulmonary edema resolution. In isolated perfused mouse and rat lungs, pharmacological inhibition of SNATs by HgCl2 and α-methylaminoisobutyric acid (MeAIB) impaired AFC. Quantitative RT-PCR identified SNAT2 as the highest expressed System A transporter in pulmonary epithelial cells. Pharmacological inhibition or siRNA-mediated knockdown of SNAT2 reduced transport of l-alanine across pulmonary epithelial cells. Homozygous Slc38a2-/- mice were subviable and died shortly after birth with severe cyanosis. Isolated lungs of Slc38a2+/- mice developed higher wet-to-dry weight ratios (W/D) as compared to wild type (WT) in response to hydrostatic stress. Similarly, W/D ratios were increased in Slc38a2+/- mice as compared to controls in an acid-induced lung injury model. Our results identify SNAT2 as a functional transporter for Na+ and neutral amino acids in pulmonary epithelial cells with a relevant role in AFC and the resolution of lung edema. Activation of SNAT2 may provide a new therapeutic strategy to counteract and/or reverse pulmonary edema.

Asunto(s)

Lesión Pulmonar Aguda/prevención & control , Sistema de Transporte de Aminoácidos A/fisiología , Agua Pulmonar Extravascular/metabolismo , Alveolos Pulmonares/metabolismo , Edema Pulmonar/prevención & control , Sodio/metabolismo , Lesión Pulmonar Aguda/inducido químicamente , Lesión Pulmonar Aguda/metabolismo , Lesión Pulmonar Aguda/patología , Animales , Ácido Clorhídrico/toxicidad , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Edema Pulmonar/metabolismo , Edema Pulmonar/patología , Ratas , Ratas Sprague-Dawley

RESUMEN

Acute respiratory distress syndrome (ARDS) is a devastating clinical syndrome that leads to acute respiratory failure and accounts for over 70,000 deaths per year in the United States alone, even prior to the COVID-19 pandemic. While its molecular details have been teased apart and its pathophysiology largely established over the past 30 years, relatively few pharmacological advances in treatment have been made based on this knowledge. Indeed, mortality remains very close to what it was 30 years ago. As an alternative to traditional pharmacological approaches, gene therapy offers a highly controlled and targeted strategy to treat the disease at the molecular level. Although there is no single gene or combination of genes responsible for ARDS, there are a number of genes that can be targeted for upregulation or downregulation that could alleviate many of the symptoms and address the underlying mechanisms of this syndrome. This review will focus on the pathophysiology of ARDS and how gene therapy has been used for prevention and treatment. Strategies for gene delivery to the lung, such as barriers encountered during gene transfer, specific classes of genes that have been targeted, and the outcomes of these approaches on ARDS pathogenesis and resolution will be discussed.

RESUMEN

Adipose-derived stromal cells (ADSCs) showed excellent capacity in regeneration and tissue protection. Low tidal volume ventilation (LVT) strategy demonstrates a therapeutic benefit on the treatment of acute lung injury/acute respiratory distress syndrome (ALI/ARDS). This study, therefore, aimed to undertaken determine whether the combined LVT and ADSCs treatment exerts additional protection against lipopolysaccharide (LPS)-induced ALI in rats. The animals were randomized into seven groups: Group I (control), Group II (instillation of LPS at 10 mg/kg intratracheally), Group III (LPS+LVT 6 ml/kg), Group IV (LPS+intravenous autologous 5 × 106 ADSCs which were pretreated with a scrambled small interfering RNA [siRNA] of keratinocyte growth factor [KGF] negative control), Group V (LPS+ADSCs which were pretreated with a scrambled siRNA of KGF, Group VI (LPS+LVT and ADSCs as in the Group IV), and Group VII (LPS+LVT and ADSCs as in the Group V). We found that levels of tumor necrosis factor-α, transforming growth factor-ß1, and interleukin (IL)-1ß and IL-6, the proinflammatory cytokines, were remarkably increased in LPS rats. Moreover, the expressions of ENaC, activity of Na, K-ATPase, and alveolar fluid clearance (AFC) were obviously reduced by LPS-induced ALI. The rats treated by ADSCs showed improved effects in all these changes of ALI and further enhanced by ADSCs combined with LVT treatment. Importantly, the treatment of ADSCs with siRNA-mediated knockdown of KGF partially eliminated the therapeutic effects. In conclusion, combined treatment with ADSCs and LVT not only is superior to either ADSCs or LVT therapy alone in the prevention of ALI. Evidence of the beneficial effect may be partly due to improving AFC by paracrine or systemic production of KGF and anti-inflammatory properties.

Asunto(s)

Lesión Pulmonar Aguda/terapia , Trasplante de Células Madre Mesenquimatosas , Trasplante Autólogo , Lesión Pulmonar Aguda/inducido químicamente , Lesión Pulmonar Aguda/patología , Tejido Adiposo/citología , Tejido Adiposo/trasplante , Animales , Modelos Animales de Enfermedad , Humanos , Lipopolisacáridos/toxicidad , Pulmón/patología , Células Madre Mesenquimatosas , Ratas , Respiración , Volumen de Ventilación Pulmonar/genética , Ventilación/normas