Targeting IL-11 system as a treatment of pulmonary arterial hypertension.

IL-11 is linked to fibrotic diseases, but its role in pulmonary hypertension is unclear. We examined IL-11's involvement in idiopathic pulmonary arterial hypertension (iPAH). Using samples from control (n = 20) and iPAH (n = 6) subjects, we assessed IL-11 and IL-11Rα expression and localization through RT-qPCR, ELISA, immunohistochemistry, and immunofluorescence. A monocrotaline-induced PAH model helped evaluate the impact of siRNA-IL-11 on pulmonary artery remodeling and PH. The effects of recombinant human IL-11 and IL-11Rα on human pulmonary artery smooth muscle cell (HPASMC) proliferation, pulmonary artery endothelial cell (HPAEC) mesenchymal transition, monocyte interactions, endothelial tube formation, and precision cut lung slice (PCLS) pulmonary artery remodeling and contraction were evaluated. IL-11 and IL-11Rα were over-expressed in pulmonary arteries (3.2-fold and 75-fold respectively) and serum (1.5-fold and 2-fold respectively) of patients with iPAH. Therapeutic transient transfection with siRNA targeting IL-11 resulted in a significant reduction in pulmonary artery remodeling (by 98%), right heart hypertrophy (by 66%), and pulmonary hypertension (by 58%) in rats exposed to monocrotaline treatment. rhIL-11 and soluble rhIL-11Rα induce HPASMC proliferation and HPAEC to monocyte interactions, mesenchymal transition, and tube formation. Neutralizing monoclonal IL-11 and IL-11Rα antibodies inhibited TGFß1 and EDN-1 induced HPAEC to mesenchymal transition and HPASMC proliferation. In 3D PCLS, rhIL-11 and soluble rhIL-11Rα do not promote pulmonary artery contraction but sensitize PCLS pulmonary artery contraction induced by EDN-1. In summary, IL-11 and IL-11Rα are more highly expressed in the pulmonary arteries of iPAH patients and contribute to pulmonary artery remodeling and the development of PH.

Obacunone Photoprotective Effects against Solar-Simulated Radiation-Induced Molecular Modifications in Primary Keratinocytes and Full-Thickness Human Skin.

Solar radiation can cause damage to the skin, leading to various adverse effects such as sunburn, reactive oxygen species production, inflammation, DNA damage, and photoaging. To study the potential of photoprotective agents, full-thickness skin models are increasingly being used as in vitro tools. One promising approach to photoprotection involves targeting the redox-sensitive transcription factor Nrf2, which is responsible for regulating various cellular defense mechanisms, including the antioxidant response, inflammatory signaling, and DNA repair. Obacunone, a natural triterpenoid, has been identified as a potent Nrf2 agonist. The present study aims to evaluate the relevance of full-thickness (FT) skin models in photoprotection studies and to explore the potential photoprotective effects of obacunone on those models and in human keratinocytes. Phenion® full-thickness skin models and keratinocytes were incubated with increasing concentrations of obacunone and irradiated with solar-simulated radiation (SSR). Various photodamage markers were evaluated, including histological integrity, oxidative stress, apoptosis, inflammation, photoaging-related dermal markers, and photocarcinogenesis markers. Increasing doses of SSR were found to modulate various biomarkers related to sun damage in the FT skin models. However, obacunone attenuated cytotoxicity, inflammation, oxidative stress, sunburn reaction, photoaging, and photocarcinogenesis in both keratinocytes and full thickness skin models exposed to SSR. These results suggest that obacunone may have potential as a photoprotective agent for preventing the harmful effects of solar radiation on the skin.

IL-11 system participates in pulmonary artery remodeling and hypertension in pulmonary fibrosis.

BACKGROUND: Pulmonary hypertension (PH) associated to idiopathic pulmonary fibrosis (IPF) portends a poor prognosis. IL-11 has been implicated in fibrotic diseases, but their role on pulmonary vessels is unknown. Here we analyzed the contribution of IL-11 to PH in patients with IPF and the potential mechanism implicated. METHODS: Pulmonary arteries, lung tissue and serum of control subjects (n = 20), IPF (n = 20) and PH associated to IPF (n = 20) were used to study the expression and localization of IL-11 and IL-11Rα. Two models of IL-11 and bleomycin-induced lung fibrosis associated to PH were used in Tie2-GFP transgenic mice to evaluate the contribution of IL-11 and endothelial cells to pulmonary artery remodeling. The effect of IL-11 and soluble IL-11Rα on human pulmonary artery endothelial cells and smooth muscle cell transformations and proliferation were analyzed. RESULTS: IL-11 and IL-11Rα were over-expressed in pulmonary arteries and serum of patients with PH associated to IPF vs IPF patients without PH. Recombinant mice (rm)IL-11 induced lung fibrosis and PH in Tie2-GFP mice, activating in vivo EnMT as a contributor of pulmonary artery remodeling and lung fibrosis. Transient transfection of siRNA-IL-11 reduced lung fibrosis and PH in Tie2-GFP bleomycin model. Human (h)rIL-11 and soluble hrIL-11Rα induced endothelial to mesenchymal transition (EnMT) and pulmonary artery smooth muscle cell to myofibroblast-like transformation, cell proliferation and senescence in vitro. CONCLUSIONS: IL-11 and IL-11Rα are overexpressed in pulmonary arteries of PH associated to IPF patients, and contributes to pulmonary artery remodeling and PH.

GSE4-loaded nanoparticles a potential therapy for lung fibrosis that enhances pneumocyte growth, reduces apoptosis and DNA damage.

Idiopathic pulmonary fibrosis is a lethal lung fibrotic disease, associated with aging with a mean survival of 2-5 years and no curative treatment. The GSE4 peptide is able to rescue cells from senescence, DNA and oxidative damage, inflammation, and induces telomerase activity. Here, we investigated the protective effect of GSE4 expression in vitro in rat alveolar epithelial cells (AECs), and in vivo in a bleomycin model of lung fibrosis. Bleomycin-injured rat AECs, expressing GSE4 or treated with GSE4-PLGA/PEI nanoparticles showed an increase of telomerase activity, decreased DNA damage, and decreased expression of IL6 and cleaved-caspase 3. In addition, these cells showed an inhibition in expression of fibrotic markers induced by TGF-ß such as collagen-I and III among others. Furthermore, treatment with GSE4-PLGA/PEI nanoparticles in a rat model of bleomycin-induced fibrosis, increased telomerase activity and decreased DNA damage in proSP-C cells. Both in preventive and therapeutic protocols GSE4-PLGA/PEI nanoparticles prevented and attenuated lung damage monitored by SPECT-CT and inhibited collagen deposition. Lungs of rats treated with bleomycin and GSE4-PLGA/PEI nanoparticles showed reduced expression of α-SMA and pro-inflammatory cytokines, increased number of pro-SPC-multicellular structures and increased DNA synthesis in proSP-C cells, indicating therapeutic efficacy of GSE4-nanoparticles in experimental lung fibrosis and a possible curative treatment for lung fibrotic patients.

Paclitaxel-Induced Epidermal Alterations: An In Vitro Preclinical Assessment in Primary Keratinocytes and in a 3D Epidermis Model.

Paclitaxel is a microtubule-stabilizing chemotherapeutic agent approved for the treatment of ovarian, non-small cell lung, head, neck, and breast cancers. Despite its beneficial effects on cancer and widespread use, paclitaxel also damages healthy tissues, including the skin. However, the mechanisms that drive these skin adverse events are not clearly understood. In the present study, we demonstrated, by using both primary epidermal keratinocytes (NHEK) and a 3D epidermis model, that paclitaxel impairs different cellular processes: paclitaxel increased the release of IL-1α, IL-6, and IL-8 inflammatory cytokines, produced reactive oxygen species (ROS) release and apoptosis, and reduced the endothelial tube formation in the dermal microvascular endothelial cells (HDMEC). Some of the mechanisms driving these adverse skin events in vitro are mediated by the activation of toll-like receptor 4 (TLR-4), which phosphorylate transcription of nuclear factor kappa B (NF-κb). This is the first study analyzing paclitaxel effects on healthy human epidermal cells with an epidermis 3D model, and will help in understanding paclitaxel's effects on the skin.

Increased Expression of Galectin-3 in Skin Fibrosis: Evidence from In Vitro and In Vivo Studies.

Skin fibrosis is a hallmark of a wide array of dermatological diseases which can greatly impact the patients' quality of life. Galectin-3 (GAL-3) has emerged as a central regulator of tissue fibrosis, playing an important pro-fibrotic role in numerous organs. Various studies are highlighting its importance as a skin fibrotic diseases biomarker; however, there is a need for further studies that clarify its role. This paper aims to ascertain whether the expression of GAL-3 is increased in relevant in vitro and in vivo models of skin fibrosis. We studied the role of GAL-3 in vitro using normal human dermal fibroblasts (NHDF) and fibrocytes. In addition, we used a skin fibrosis murine model (BALB/c mice) and human biopsies of healthy or keloid tissue. GAL-3 expression was analyzed using real time PCR, Western blot and immunostaining techniques. We report a significantly increased expression of GAL-3 in NHDF and fibrocytes cell cultures following stimulation with transforming growth factor ß1 (TGFß1). In vivo, GAL-3 expression was increased in a murine model of systemic sclerosis and in human keloid biopsies. In sum, this study underlines the involvement of GAL-3 in skin fibrosis using several models of the disease and highlights its role as a relevant target.

N-acetylcysteine Reduces Inflammasome Activation Induced by SARS-CoV-2 Proteins In Vitro.

Inflammasome activation is one of the first steps in initiating innate immune responses. In this work, we studied the activation of inflammasomes in the airways of critically ill COVID-19 patients and the effects of N-acetylcysteine (NAC) on inflammasomes. Tracheal biopsies were obtained from critically ill patients without COVID-19 and no respiratory disease (control, n = 32), SARS-CoV-2 B.1 variant (n = 31), and B.1.1.7 VOC alpha variant (n = 20) patients. Gene expression and protein expression were measured by RT-qPCR and immunohistochemistry. Macrophages and bronchial epithelial cells were stimulated with different S, E, M, and N SARS-CoV-2 recombinant proteins in the presence or absence of NAC. NLRP3 inflammasome complex was over-expressed and activated in the COVID-19 B.1.1.7 VOC variant and associated with systemic inflammation and 28-day mortality. TLR2/MyD88 and redox NOX4/Nrf2 ratio were also over-expressed in the COVID-19 B.1.1.7 VOC variant. The combination of S-E-M SARS-CoV-2 recombinant proteins increased cytokine release in macrophages and bronchial epithelial cells through the activation of TLR2. NAC inhibited SARS-CoV-2 mosaic (S-E-M)-induced cytokine release and inflammasome activation. In summary, inflammasome is over-activated in severe COVID-19 and increased in B.1.1.7 VOC variant. In addition, NAC can reduce inflammasome activation induced by SARS-CoV-2 in vitro, which may be of potential translational value in COVID-19 patients.

AAV1.SERCA2a Gene Therapy Reverses Pulmonary Fibrosis by Blocking the STAT3/FOXM1 Pathway and Promoting the SNON/SKI Axis.

Inhibition of pulmonary fibrosis (PF) by restoring sarco/endoplasmic reticulum calcium ATPase 2a isoform (SERCA2a) expression using targeted gene therapy may be a potentially powerful new treatment approach for PF. Here, we found that SERCA2a expression was significantly decreased in lung samples from patients with PF and in the bleomycin (BLM) mouse model of PF. In the BLM-induced PF model, intratracheal aerosolized adeno-associated virus serotype 1 (AAV1) encoding for human SERCA2a (AAV1.hSERCA2a) reduces lung fibrosis and associated vascular remodeling. SERCA2a gene therapy also decreases right ventricular pressure and hypertrophy in both prevention and curative protocols. In vitro, we observed that SERCA2a overexpression inhibits fibroblast proliferation, migration, and fibroblast-to-myofibroblast transition induced by transforming growth factor ß (TGF-ß1). Thus, pro-fibrotic gene expression is prevented by blocking nuclear factor κB (NF-κB)/interleukin-6 (IL-6)-induced signal transducer and activator of transcription 3 (STAT3) activation. This effect is signaled toward an inhibitory mechanism of small mother against decapentaplegic (SMAD)/TGF-ß signaling through the repression of OTU deubiquitinase, ubiquitin aldehyde binding 1 (OTUB1) and Forkhead box M1 (FOXM1). Interestingly, this cross-inhibition leads to an increase of SKI and SnoN expression, an auto-inhibitory feedback loop of TGF-ß signaling. Collectively, our results demonstrate that SERCA2a gene transfer attenuates bleomycin (BLM)-induced PF by blocking the STAT3/FOXM1 pathway and promoting the SNON/SKI Axis. Thus, SERCA2a gene therapy may be a potential therapeutic target for PF.

Role of JAK/STAT in Interstitial Lung Diseases; Molecular and Cellular Mechanisms.

Interstitial lung diseases (ILDs) comprise different fibrotic lung disorders characterized by cellular proliferation, interstitial inflammation, and fibrosis. The JAK/STAT molecular pathway is activated under the interaction of a broad number of profibrotic/pro-inflammatory cytokines, such as IL-6, IL-11, and IL-13, among others, which are increased in different ILDs. Similarly, several growth factors over-expressed in ILDs, such as platelet-derived growth factor (PDGF), transforming growth factor ß1 (TGF-ß1), and fibroblast growth factor (FGF) activate JAK/STAT by canonical or non-canonical pathways, which indicates a predominant role of JAK/STAT in ILDs. Between the different JAK/STAT isoforms, it appears that JAK2/STAT3 are predominant, initiating cellular changes observed in ILDs. This review analyzes the expression and distribution of different JAK/STAT isoforms in ILDs lung tissue and different cell types related to ILDs, such as lung fibroblasts and alveolar epithelial type II cells and analyzes JAK/STAT activation. The effect of JAK/STAT phosphorylation on cellular fibrotic processes, such as proliferation, senescence, autophagy, endoplasmic reticulum stress, or epithelial/fibroblast to mesenchymal transition will be described. The small molecules directed to inhibit JAK/STAT activation were assayed in vitro and in in vivo models of pulmonary fibrosis, and different JAK inhibitors are currently approved for myeloproliferative disorders. Recent evidence indicates that JAK inhibitors or monoclonal antibodies directed to block IL-6 are used as compassionate use to attenuate the excessive inflammation and lung fibrosis related to SARS-CoV-2 virus. These altogether indicate that JAK/STAT pathway is an attractive target to be proven in future clinical trials of lung fibrotic disorders.

The Role of JAK/STAT Molecular Pathway in Vascular Remodeling Associated with Pulmonary Hypertension.

Pulmonary hypertension is defined as a group of diseases characterized by a progressive increase in pulmonary vascular resistance (PVR), which leads to right ventricular failure and premature death. There are multiple clinical manifestations that can be grouped into five different types. Pulmonary artery remodeling is a common feature in pulmonary hypertension (PH) characterized by endothelial dysfunction and smooth muscle pulmonary artery cell proliferation. The current treatments for PH are limited to vasodilatory agents that do not stop the progression of the disease. Therefore, there is a need for new agents that inhibit pulmonary artery remodeling targeting the main genetic, molecular, and cellular processes involved in PH. Chronic inflammation contributes to pulmonary artery remodeling and PH, among other vascular disorders, and many inflammatory mediators signal through the JAK/STAT pathway. Recent evidence indicates that the JAK/STAT pathway is overactivated in the pulmonary arteries of patients with PH of different types. In addition, different profibrotic cytokines such as IL-6, IL-13, and IL-11 and growth factors such as PDGF, VEGF, and TGFß1 are activators of the JAK/STAT pathway and inducers of pulmonary remodeling, thus participating in the development of PH. The understanding of the participation and modulation of the JAK/STAT pathway in PH could be an attractive strategy for developing future treatments. There have been no studies to date focused on the JAK/STAT pathway and PH. In this review, we focus on the analysis of the expression and distribution of different JAK/STAT isoforms in the pulmonary arteries of patients with different types of PH. Furthermore, molecular canonical and noncanonical JAK/STAT pathway transactivation will be discussed in the context of vascular remodeling and PH. The consequences of JAK/STAT activation for endothelial cells and pulmonary artery smooth muscle cells' proliferation, migration, senescence, and transformation into mesenchymal/myofibroblast cells will be described and discussed, together with different promising drugs targeting the JAK/STAT pathway in vitro and in vivo.

MUC16 Is Overexpressed in Idiopathic Pulmonary Fibrosis and Induces Fibrotic Responses Mediated by Transforming Growth Factor-ß1 Canonical Pathway.

Several transmembrane mucins have demonstrated that they contribute intracellularly to induce fibrotic processes. The extracellular domain of MUC16 is considered as a biomarker for disease progression and death in IPF patients. However, there is no evidence regarding the signalling capabilities of MUC16 that contribute to IPF development. Here, we demonstrate that MUC16 was overexpressed in the lung tissue of IPF patients (n = 20) compared with healthy subjects (n = 17) and localised in fibroblasts and hyperplastic alveolar type II cells. Repression of MUC16 expression by siRNA-MUC16 transfection inhibited the TGF-ß1-induced fibrotic processes such as mesenchymal/ myofibroblast transformations of alveolar type II A549 cells and lung fibroblasts, as well as fibroblast proliferation. SiRNA-MUC16 transfection also decreased the TGF-ß1-induced SMAD3 phosphorylation, thus inhibiting the Smad Binding Element activation. Immunoprecipitation assays and confocal immunofluorescence showed the formation of a protein complex between MUC16/p-SMAD3 in the cell membrane after TGF-ß1 stimulation. This study shows that MUC16 is overexpressed in IPF and collaborates with the TGF-ß1 canonical pathway to induce fibrotic processes. Therefore, direct or indirect targeting of MUC16 could be a potential drug target for human IPF.

MUC1 intracellular bioactivation mediates lung fibrosis.

BACKGROUND: Serum KL6/mucin 1 (MUC1) has been identified as a potential biomarker in idiopathic pulmonary fibrosis (IPF), but the role of MUC1 intracellular bioactivation in IPF is unknown. OBJECTIVE: To characterise MUC1 intracellular bioactivation in IPF. METHODS AND RESULTS: The expression and phosphorylation of Thr41 and Tyr46 on the intracellular MUC1-cytoplasmic tail (CT) was increased in patients with IPF (n=22) compared with healthy subjects (n=21) and localised to fibroblasts and hyperplastic alveolar type II cells. Transforming growth factor (TGF)-ß1 phosphorylated SMAD3 and thereby increased the phosphorylation of MUC1-CT Thr41 and Tyr46 in lung fibroblasts and alveolar type II cells, activating ß-catenin to form a phospho-Smad3/MUC1-CT and MUC1-CT/ß-catenin nuclear complex. This nuclear complex promoted alveolar epithelial type II and fibroblast to myofibroblast transitions, as well as cell senescence and fibroblast proliferation. The inhibition of MUC1-CT nuclear translocation using the inhibitor, GO-201 or silencing MUC1 by siRNA, reduced myofibroblast transition, senescence and proliferation in vitro. Bleomycin-induced lung fibrosis was reduced in mice treated with GO-201 and in MUC1-knockout mice. The profibrotic lectin, galectin-3, directly activated MUC1-CT and served as a bridge between the TGF-ß receptor and the MUC1-C domain, indicating TGF-ß1-dependent and TGF-ß1-independent intracellular bioactivation of MUC1. CONCLUSIONS: MUC1 intracellular bioactivation is enhanced in IPF and promotes fibrotic processes that could represent potential druggable targets for IPF.

Pharmacological Profile of AZD8871 (LAS191351), a Novel Inhaled Dual M3 Receptor Antagonist/ß 2-Adrenoceptor Agonist Molecule with Long-Lasting Effects and Favorable Safety Profile.

AZD8871 is a novel muscarinic antagonist and ß 2-adrenoceptor agonist in development for chronic obstructive pulmonary disease. This study describes the pharmacological profile of AZD8871 in in vitro and in vivo assays. AZD8871 is potent at the human M3 receptor (pIC50 in binding assays: 9.5) and shows kinetic selectivity for the M3 (half-life: 4.97 hours) over the M2 receptor (half-life: 0.46 hour). It is selective for the ß 2-adrenoceptor over the ß 1 and ß 3 subtypes (3- and 6-fold, respectively) and shows dual antimuscarinic and ß 2-adrenoceptor functional activity in isolated guinea pig tissue (pIC50 in electrically stimulated trachea: 8.6; pEC50 in spontaneous tone isolated trachea: 8.8, respectively), which are sustained over time. AZD8871 exhibits a higher muscarinic component than batefenterol in human bronchi, with a shift in potency under propranolol blockade of 2- and 6-fold, respectively, together with a persisting relaxation (5.3% recovery at 8 hours). Nebulized AZD8871 prevents acetylcholine-induced bronchoconstriction in both guinea pig and dog with minimal effects on salivation and heart rate at doses with bronchoprotective activity. Moreover, AZD8871 shows long-lasting effects in dog, with a bronchoprotective half-life longer than 24 hours. In conclusion, these studies demonstrate that AZD8871 is a dual-acting molecule with a high muscarinic component and a long residence time at the M3 receptor; moreover, its preclinical profile in animal models suggests a once-daily dosing in humans and a favorable safety profile. Thus, AZD8871 has the potential to be a next generation of inhaled bronchodilators in respiratory diseases.

Mucin 1 deficiency mediates corticosteroid insensitivity in asthma.

BACKGROUND: The loss of corticosteroid efficacy is an important issue in severe asthma management and may lead to poor asthma control and deterioration of airflow. Recent data indicate that Mucin 1 (MUC1) membrane mucin can mediate corticosteroid efficacy in chronic rhinosinusitis, but the role of MUC1 in uncontrolled severe asthma is unknown. The objective was to analyze the previously unexplored role of MUC1 on corticosteroid efficacy in asthma. METHODS: Mucin 1 expression was evaluated by real-time PCR in human bronchial epithelial cells (HBEC) and blood neutrophils from uncontrolled severe asthma (n = 27), controlled mild asthma (n = 16), and healthy subjects (n = 13). IL-8, MMP9, and GM-CSF were measured by ELISA in HBEC and neutrophils. An asthma model of ovalbumin (OVA) was used in MUC1 KO and WT C57BL/6 mice according to ARRIVE guidelines. RESULTS: Mucin 1-CT expression was downregulated in bronchial epithelial cells and peripheral blood neutrophils from severe asthma patients compared with mild asthma and healthy subjects (P < 0.05). Daily dose of inhaled corticosteroids (ICS) inversely correlated with MUC1 expression in neutrophils from mild and severe asthma (ρ = -0.71; P < 0.0001). Dexamethasone showed lower anti-inflammatory effects in severe asthma peripheral blood neutrophils and HBECs stimulated with lipopolysaccharide (LPS) than in cells from mild asthma. Glucocorticoid receptor (GR)-α phosphorylated at serine 226 was increased in cells from severe asthma, and the MUC1-CT/GRα complex was downregulated in severe asthma cells. OVA asthma model in MUC1 KO mice was resistant to the anti-inflammatory effects of dexamethasone. CONCLUSION: Mucin 1-CT modulates corticosteroid efficacy in vitro and in vivo asthma models.

Idiopathic Pulmonary Fibrosis and Lung Cancer: Mechanisms and Molecular Targets.

Idiopathic pulmonary fibrosis (IPF) is the most common idiopathic interstitial pulmonary disease with a median survival of 2⁻4 years after diagnosis. A significant number of IPF patients have risk factors, such as a history of smoking or concomitant emphysema, both of which can predispose the patient to lung cancer (LC) (mostly non-small cell lung cancer (NSCLC)). In fact, IPF itself increases the risk of LC development by 7% to 20%. In this regard, there are multiple common genetic, molecular, and cellular processes that connect lung fibrosis with LC, such as myofibroblast/mesenchymal transition, myofibroblast activation and uncontrolled proliferation, endoplasmic reticulum stress, alterations of growth factors expression, oxidative stress, and large genetic and epigenetic variations that can predispose the patient to develop IPF and LC. The current approved IPF therapies, pirfenidone and nintedanib, are also active in LC. In fact, nintedanib is approved as a second line treatment in NSCLC, and pirfenidone has shown anti-neoplastic effects in preclinical studies. In this review, we focus on the current knowledge on the mechanisms implicated in the development of LC in patients with IPF as well as in current IPF and LC-IPF candidate therapies based on novel molecular advances.

JAK2 mediates lung fibrosis, pulmonary vascular remodelling and hypertension in idiopathic pulmonary fibrosis: an experimental study.

BACKGROUND: Pulmonary hypertension (PH) is a common disorder in patients with idiopathic pulmonary fibrosis (IPF) and portends a poor prognosis. Recent studies using vasodilators approved for PH have failed in improving IPF mainly due to ventilation (V)/perfusion (Q) mismatching and oxygen desaturation. Janus kinase type 2 (JAK2) is a non-receptor tyrosine kinase activated by a broad spectrum of profibrotic and vasoactive mediators, but its role in PH associated to PH is unknown. OBJECTIVE: The study of JAK2 as potential target to treat PH in IPF. METHODS AND RESULTS: JAK2 expression was increased in pulmonary arteries (PAs) from IPF (n=10; 1.93-fold; P=0.0011) and IPF+PH (n=9; 2.65-fold; P<0.0001) compared with PA from control subjects (n=10). PA remodelling was evaluated in human pulmonary artery endothelial cells (HPAECs) and human pulmonary artery smooth muscle cells (HPASMCs) from patients with IPF in vitro treated with the JAK2 inhibitor JSI-124 or siRNA-JAK2 and stimulated with transforming growth factor beta. Both JSI-124 and siRNA-JAK2 inhibited the HPAEC to mesenchymal transition and the HPASMCs to myofibroblast transition and proliferation. JAK2 inhibition induced small PA relaxation in precision-cut lung slice experiments. PA relaxation was dependent of the large conductance calcium-activated potassium channel (BKCa). JAK2 inhibition activated BKCa channels and reduced intracellular Ca2+. JSI-124 1 mg/kg/day, reduced bleomycin-induced lung fibrosis, PA remodelling, right ventricular hypertrophy, PA hypertension and V/Q mismatching in rats. The animal studies followed the ARRIVE guidelines. CONCLUSIONS: JAK2 participates in PA remodelling and tension and may be an attractive target to treat IPF associated to PH.

MUC1 deficiency mediates corticosteroid resistance in chronic obstructive pulmonary disease.

BACKGROUND: Lung inflammation in COPD is poorly controlled by inhaled corticosteroids (ICS). Strategies to improve ICS efficacy or the search of biomarkers who may select those patients candidates to receive ICS in COPD are needed. Recent data indicate that MUC1 cytoplasmic tail (CT) membrane mucin can mediate corticosteroid efficacy in chronic rhinosinusitis. The objective of this work was to analyze the previously unexplored role of MUC1 on corticosteroid efficacy in COPD in vitro and in vivo models. METHODS: MUC1-CT expression was measured by real time PCR, western blot, immunohistochemistry and immunofluorescence. The inflammatory mediators IL-8, MMP9, GM-CSF and MIP3α were measured by ELISA. The effect of MUC1 on inflammation and corticosteroid anti-inflammatory effects was measured using cell siRNA in vitro and Muc1-KO in vivo animal models. RESULTS: MUC1-CT expression was downregulated in lung tissue, bronchial epithelial cells and lung neutrophils from smokers (n = 11) and COPD (n = 11) patients compared with healthy subjects (n = 10). MUC1 was correlated with FEV1% (ρ = 0.7479; p < 0.0001) in smokers and COPD patients. Cigarette smoke extract (CSE) decreased the expression of MUC1 and induced corticosteroid resistance in human primary bronchial epithelial cells and human neutrophils. MUC1 Gene silencing using siRNA-MUC1 impaired the anti-inflammatory effects of dexamethasone and reduced glucocorticoid response element activation. Dexamethasone promoted glucocorticoid receptor alpha (GRα) and MUC1-CT nuclear translocation and co-localization that was inhibited by CSE. Lung function decline and inflammation induced by lipopolysaccharide and cigarette smoke in Muc1 KO mice was resistant to dexamethasone. CONCLUSIONS: These results confirm a role for MUC1-CT mediating corticosteroid efficacy in COPD.

The JAK2 pathway is activated in idiopathic pulmonary fibrosis.

BACKGROUND: Idiopathic pulmonary fibrosis (IPF) is the most rapidly progressive and fatal fibrotic disorder, with no curative therapies. The signal transducer and activator of transcription 3 (STAT3) protein is activated in lung fibroblasts and alveolar type II cells (ATII), thereby contributing to lung fibrosis in IPF. Although activation of Janus kinase 2 (JAK2) has been implicated in proliferative disorders, its role in IPF is unknown. The aim of this study was to analyze JAK2 activation in IPF, and to determine whether JAK2/STAT3 inhibition is a potential therapeutic strategy for this disease. METHODS AND RESULTS: JAK2/p-JAK2 and STAT3/pSTAT3 expression was evaluated using quantitative real time-PCR, western blotting, and immunohistochemistry. Compared to human healthy lung tissue (n = 10) both proteins were upregulated in the lung tissue of IPF patients (n = 12). Stimulating primary ATII and lung fibroblasts with transforming growth factor beta 1 or interleukin (IL)-6/IL-13 activated JAK2 and STAT3, inducing epithelial to mesenchymal and fibroblast to myofibroblast transitions. Dual p-JAK2/p-STAT3 inhibition with JSI-124 or silencing of JAK2 and STAT3 genes suppressed ATII and the fibroblast to myofibroblast transition, with greater effects than the sum of those obtained using JAK2 or STAT3 inhibitors individually. Dual rather than single inhibition was also more effective for inhibiting fibroblast migration, preventing increases in fibroblast senescence and Bcl-2 expression, and ameliorating impaired autophagy. In rats administered JSI-124, a dual inhibitor of p-JAK2/p-STAT3, at a dose of 1 mg/kg/day, bleomycin-induced lung fibrosis was reduced and collagen deposition in the lung was inhibited, as were JAK2 and STAT3 activation and several markers of fibrosis, autophagy, senescence, and anti-apoptosis. CONCLUSIONS: JAK2 and STAT3 are activated in IPF, and their dual inhibition may be an attractive strategy for treating this disease.

Deciphering function of the pulmonary arterial sphincters in loggerhead sea turtles (Caretta caretta).

To provide new insight into the pathophysiological mechanisms underlying gas emboli (GE) in bycaught loggerhead sea turtles (Caretta caretta), we investigated the vasoactive characteristics of the pulmonary and systemic arteries, and the lung parenchyma (LP). Tissues were opportunistically excised from recently dead animals for in vitro studies of vasoactive responses to four different neurotransmitters: acetylcholine (ACh; parasympathetic), serotonin (5HT), adrenaline (Adr; sympathetic) and histamine. The significant amount of smooth muscle in the LP contracted in response to ACh, Adr and histamine. The intrapulmonary and systemic arteries contracted under both parasympathetic and sympathetic stimulation and when exposed to 5HT. However, proximal extrapulmonary arterial (PEPA) sections contracted in response to ACh and 5HT, whereas Adr caused relaxation. In sea turtles, the relaxation in the pulmonary artery was particularly pronounced at the level of the pulmonary artery sphincter (PASp), where the vessel wall was highly muscular. For comparison, we also studied tissue response in freshwater sliders turtles (Trachemys scripta elegans). Both PEPA and LP from freshwater sliders contracted in response to 5HT, ACh and also Adr. We propose that in sea turtles, the dive response (parasympathetic tone) constricts the PEPA, LP and PASp, causing a pulmonary shunt and limiting gas uptake at depth, which reduces the risk of GE during long and deep dives. Elevated sympathetic tone caused by forced submersion during entanglement with fishing gear increases the pulmonary blood flow causing an increase in N2 uptake, potentially leading to the formation of blood and tissue GE at the surface. These findings provide potential physiological and anatomical explanations on how these animals have evolved a cardiac shunt pattern that regulates gas exchange during deep and prolonged diving.

MUC4 impairs the anti-inflammatory effects of corticosteroids in patients with chronic rhinosinusitis with nasal polyps.

BACKGROUND: Current evidence suggests that membrane-tethered mucins could mediate corticosteroid efficacy, interacting with glucocorticoid receptor (GR) in patients with chronic rhinosinusitis with nasal polyps (CRSwNP). Mucin 4 (MUC4)-tethered mucin is expressed in nasal polyp (NP) epithelial cells and upregulated under inflammatory conditions. Moreover, MUC4ß has the capacity to interact with other intracellular proteins. We hypothesized that MUC4 modulates corticosteroid efficacy of patients with CRSwNP. OBJECTIVE: We sought to analyze the role of MUC4 in corticosteroid effectiveness in different cohorts of patients with CRSwNP and elucidate the possible mechanisms involved. METHODS: Eighty-one patients with CRSwNP took oral corticosteroids for 15 days. Corticosteroid resistance was evaluated by using nasal endoscopy. Expression of MUC4 and MUC4ß was evaluated by means of real-time PCR, Western blotting, and immunohistochemistry. BEAS-2B knockdown with RNA interference for MUC4 (small interfering RNA [siRNA]-MUC4) was used to analyze the role of MUC4 in the anti-inflammatory effects of dexamethasone. RESULTS: Twenty-two patients had NPs resistant to oral corticosteroids. MUC4 expression was upregulated in these patients. In siRNA-MUC4 BEAS-2B airway epithelial cells dexamethasone produced higher anti-inflammatory effects, increased inhibition of phospho-extracellular signal-regulated kinase 1/2, increased mitogen-activated protein kinase phosphatase 1 expression, and increased glucocorticoid response element activation. Immunoprecipitation and immunofluorescence experiments revealed that MUC4ß forms a complex with GRα in the nuclei of NP epithelial cells from corticosteroid-resistant patients. CONCLUSION: MUC4ß participates in the corticosteroid resistance process, inhibiting normal GRα nuclear function. The high expression of MUC4 in patients with CRSwNP might participate in corticosteroid resistance.