Pharmacological Inhibition of Epac1 Protects against Pulmonary Fibrosis by Blocking FoxO3a Neddylation.

Background: Idiopathic Pulmonary fibrosis (IPF) is characterized by progressive scarring and fibrosis within the lungs. There is currently no cure for IPF; therefore, there is an urgent need to identify novel therapeutic targets that can prevent the progression of IPF. Compelling evidence indicates that the second messenger, cyclic adenosine monophosphate (cAMP), inhibits lung fibroblast proliferation and differentiation through the classical PKA pathway. However, the contribution of the e xchange p rotein directly a ctivated by c AMP 1 (Epac1) to IPF pathophysiological processes is yet to be investigated. Objective: To determine the role of the cAMP-binding protein Epac1 in the progression of IPF. Methods: We used lung samples from IPF patients or healthy controls, mouse lung samples, or lung fibroblast isolated from a preclinical mouse model of PF induced by bleomycin intratracheal injection. The effect of bleomycin (BLM) treatment was determined in Epac1 knock-out mice or wild-type littermates. Epac1 expression was modulated in vitro by using lentiviral vectors or adenoviruses. The therapeutic potential of the Epac1-selective pharmacological inhibitor, AM-001, was tested in vivo and in vitro, using a bleomycin mouse model of PF and an ex vivo precision-cut lung slices (PCLs) model of human lung fibrosis. Results: Epac1 expression was increased in the lung tissue of IPF patients, in IPF-diseased fibroblasts and in BLM-challenged mice. Furthermore, Epac1 genetic or pharmacological inhibition with AM-001 decreased normal and IPF fibroblast proliferation and the expression of profibrotic markers, αSMA, TGF-ß/SMAD2/3, and interleukin-6 (IL-6)/STAT3 signaling pathways. Consistently, blocking Epac1 protected against BLM-induced lung injury and fibrosis, suggesting a therapeutic effect of Epac1 inhibition on PF pathogenesis and progression. Global gene expression profiling revealed a decrease in the key components of the profibrotic gene signature and neddylation pathway in Epac1-deficient lung fibroblasts and IPF human-derived PLCs. Mechanistically, the protective effect of Epac1 inhibition against PF development involves the inhibition of FoxO3a neddylation and its subsequent degradation by NEDD8, and in part, by limiting the proliferative capacity of lung-infiltrating monocytes. Conclusions: We demonstrated that Epac1 is an important regulator of the pathological state of fibroblasts in PF and that small molecules targeting Epac1 can serve as novel therapeutic drugs against PF.

Pirfenidone and nintedanib attenuates pulmonary artery endothelial and smooth muscle cells transformations induced by IL-11.

Idiopathic pulmonary fibrosis (IPF) associated to pulmonary hypertension (PH) portends a poor prognosis, characterized by lung parenchyma fibrosis and pulmonary artery remodeling. Serum and parenchyma levels of Interleukin 11 (IL-11) are elevated in IPF-PH patients and contributes to pulmonary artery remodeling and PH. However, the effect of current approved therapies against IPF in pulmonary artery remodeling induced by IL-11 is unknown. The aim of this study is to analyze the effects of nintedanib and pirfenidone on pulmonary artery endothelial and smooth muscle cell remodeling induced by IL-11 in vitro. Our results show that nintedanib (NTD) and pirfenidone (PFD) ameliorates endothelial to mesenchymal transition (EnMT), pulmonary artery smooth muscle cell to myofibroblast-like transformation and pulmonary remodeling in precision lung cut slices. This study provided also evidence of the inhibitory effect of PFD and NTD on IL-11-induced endothelial and muscle cells proliferation and senescence. The inhibitory effect of these drugs on monocyte arrest and angiogenesis was also studied. Finally, we observed that IL-11 induced canonical signal transducer and activator of transcription 3 (STAT3) and non-canonical mitogen-activated protein kinase 1/2 (ERK1/2) phosphorylation, but, PFD and NTD only inhibited ERK1/2 phosphorylation. Therefore, this study provided evidence of the inhibitory effect of NTD and PFD on markers of pulmonary artery remodeling induced by IL-11.

Paclitaxel alters melanogenesis and causes pigmentation in the skin of gynecological cancer patients.

BACKGROUND: Paclitaxel (PTX) is a microtubule-stabilizing antineoplastic that has been shown to damage healthy tissues like the skin. Hyperpigmentation can be found among the adverse effects caused by PTX, but the literature is limited and the mechanisms driving PTX-induced pigmentary alterations are unknown. OBJECTIVES: This study aimed to describe the pigmentary alterations caused by PTX and to determine the effects of PTX on melanocytes. METHODS: Pigmentary skin alterations were measured in 20 gynecological cancer patients under PTX treatment by using specific probes, which determine the melanin index and the pigmentation level. Melanocytes were incubated with paclitaxel to analyze melanogenesis markers gene expression, melanin content, and transcription factors activation. RESULTS: Paclitaxel induced alterations in the skin pigmentation with no visible clinical manifestations. Gynecological cancer patients under paclitaxel treatment had an increase in the melanin index and pigmentation levels. In vitro, PTX exposure to melanocytes increased the expression of melanogenesis markers, melanin content, and induced activation of ERK and MITF. CONCLUSIONS: The results suggest that PTX alters pigmentation in patients with no clinically visible manifestations, and these alterations might be driven by its capacity to stimulate melanogenesis on melanocytes through the MITF activation pathway.

Damaging effects of UVA, blue light, and infrared radiation: in vitro assessment on a reconstructed full-thickness human skin.

Introduction: Exposure to solar radiation can cause a range of skin damage, including sunburn, erythema, skin carcinogenesis, the release of reactive oxygen species (ROS), inflammation, DNA damage, and photoaging. Other wavelengths beyond UVB, such as UVA, blue light, and infrared radiation, can also contribute to the harmful effects of solar radiation. Reconstructed full-thickness human skin has the potential to serve as effective predictive in vitro tools for evaluating the effects of solar radiation on the skin. The aim of this work was to evaluate the damaging effects of UVA, blue light, and infrared radiation in a full-thickness skin model in terms of viability, inflammation, photoaging, tissue damage, photocarcinogenesis. Methods: Full thickness skin models were purchased from Henkel (Phenion FT; Düsseldorf, Germany), and irradiated with increasing doses of UVA, blue light, or infrared radiation. Different endpoints were analyzed on the tissues: Hematoxylin-eosin staining, inflammation mediators, photoaging-related dermal markers and oxidative stress marker GPX1, evaluated by real-time quantitative PCR, as well as photocarcinogenesis markers by Western Blot. Results and Discussion: The results showed differential responses in cytokine release for each light source. In terms of photoaging biomarkers, collagen, metalloproteinases 1 and 9, elastin, and decorin were modulated by UVA and blue light exposure, while not all these markers were affected by infrared radiation. Furthermore, exposure to UVA and blue light induced loss of fibroblasts and modulation of the photocarcinogenesis markers p53 and p21. In conclusion, the presented results suggest that the various wavelengths of solar light have distinct and differential damaging effects on the skin. Understanding the differential effects of UVA, blue light, and infrared radiation can serve as a valuable tool to investigate the efficacy of photoprotective agents in full thickness skin models.

Mechanisms underlying corticosteroid resistance in patients with asthma: a review of current knowledge.

INTRODUCTION: Corticosteroids are the most cost-effective anti-inflammatory drugs available for the treatment of asthma. Despite their effectiveness, several asthmatic patients have corticosteroid resistance or insensitivity and exhibit a poor response. Corticosteroid insensitivity implies a poor prognosis due to challenges in finding alternative therapeutic options for asthma. AREAS COVERED: In this review, we describe asthma phenotypes and endotypes, as well as their differential responsiveness to corticosteroids. In addition, we describe the mechanism of action of corticosteroids underlying their regulation of the expression of glucocorticoid receptors (GRs) and their anti-inflammatory effects. Furthermore, we summarize the mechanistic evidence underlying corticosteroid-insensitive asthma, which is mainly related to changes in GR gene expression, structure, and post-transcriptional modifications. Finally, various pharmacological strategies designed to reverse corticosteroid insensitivity are discussed. EXPERT OPINION: Corticosteroid insensitivity is influenced by the asthma phenotype, endotype, and severity, and serves as an indication for biological therapy. The molecular mechanisms underlying corticosteroid-insensitive asthma have been used to develop targeted therapeutic strategies. However, the lack of clinical trials prevents the clinical application of these treatments.

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.

Influence of dose and exposition time in the effectiveness of N-Acetyl-l-cysteine treatment in A549 human epithelial cells.

N-Acetyl-l-cysteine (NAC) acts as a precursor of the tripeptide glutathione (GSH), one of the principal cell mechanisms for reactive oxygen species (ROS) detoxification. Chronic obstructive pulmonary disease (COPD) is associated with enhanced inflammatory response and oxidative stress and NAC has been used to suppress various pathogenic processes in this disease. Studies show that the effects of NAC are dose-dependent, and it appears that the efficient doses in vitro are usually higher than the achieved in vivo plasma concentrations. However, to date, the inconsistencies between the in vitro NAC antioxidant and anti-inflammatory in vitro effects, by reproducing the in vivo NAC plasma concentrations as well as high NAC concentrations. To do so, A549 were transfected with polyinosinic-polycytidylic acid (Poly (I:C)) and treated with NAC at different treatment periods. Oxidative stress, release of proinflammatory mediators and NFkB activation were analyzed. Results suggest that NAC at low doses in chronic administration has sustained antioxidant and anti-inflammatory effects, while acute treatment with high dose NAC exerts a strong antioxidant and anti-inflammatory response.

Molecular and Clinical Predictors of Quality of Life in Chronic Rhinosinusitis with Nasal Polyps.

(1) Background: Factors influencing the quality of life (QoL) of patients with chronic rhinosinusitis with nasal polyposis (CRSwNP) are poorly understood. We set out to determine the predictive factors on patients' QoL using the Sino-Nasal Outcome Test-22 (SNOT-22); (2) Methods: An ambispective analysis of data from patients diagnosed with CRSwNP in our institution. All the patients underwent a nasal polyp biopsy and completed the SNOT-22 questionnaire. Demographic and molecular data as well as the SNOT-22 scores were collected. Patients were classified in six subgroups considering the presence of asthma, non-steroidal drugs (NSAID) intolerance and corticosteroid resistance; (3) Results: The mean SNOT-22 score was 39. Considering the clinical parameters, the SNOT-22 value was significantly associated with NSAID intolerance (p = 0.04) and the endoscopic polyp score (p = 0.04). A high SNOT-22 value was also correlated with high tissue eosinophilia (p = 0.01) and high IL-8 expression; (4) Conclusions: Eosinophilia, IL-8 expression and NSAID intolerance can be used as predictors of worse QoL in patients with CRSwNP.

Evaluation of Delayed-Type Hypersensitivity to Antineoplastic Drugs-An Overview.

Nowadays, clinical practice encounters the problem of delayed-type hypersensitivity (DTH) induced by several drugs. Antineoplastic treatments are among the drugs which show an elevated proportion of DHT reactions, leading to the worsening of patients' quality of life. The range of symptoms in DHT reactions can vary from mild, such as self-limiting maculopapular eruptions, to severe, such as Stevens-Johnson Syndrome. The development of these reactions supposes a negative impact, not only by limiting patients' quality of life, but also leading to economic loss due to market withdrawal of the affected drugs and high hospitalization costs. However, despite this problem, there are no available standard in vitro or in vivo methods that allow for the evaluation of the sensitizing potential of drugs in the preclinical phase. Therefore, the aim of this review is to summarize the skin reactions caused by the different antineoplastic families, followed by a comprehensive evaluation of the in vitro and in vivo methods used to detect DTHs and that could be suitable to test antineoplastic hypersensitivity reactions.

Determining What Represents Value in the Treatment of Refractory or Unexplained Chronic Cough from the Perspective of Key Stakeholders in Spain Using Multi-Criteria Decision Analysis.

BACKGROUND AND OBJECTIVE: Chronic cough is defined as cough lasting for more than 8 weeks. It can be described as refractory when persisting despite thorough clinical assessment and treatment of any cough-related underlying condition, or unexplained when no underlying cough-related condition can be identified. Refractory or unexplained chronic cough (RCC|UCC) greatly affects patient health-related quality of life (HRQoL). Although around 10% of the population suffer from chronic cough (with 40-60% of these patients suffering from RCC|UCC), there is limited information available in the literature about the condition and the assessment of treatment success. This study aimed to determine what represents value in the treatment of RCC|UCC from the perspective of key stakeholders in Spain using Multi-Criteria Decision Analysis (MCDA) methodology. METHODS: A literature review was conducted to adapt the MCDA framework to the specific context of RCC|UCC. A total of 24 participants were involved, representing three key stakeholder groups (7 patients, 9 physicians and 8 hospital pharmacists). The study was structured in two phases. In Phase 1, participants validated the adapted MCDA framework and assigned relative weights (100-point allocation) to the framework's value criteria/sub-criteria during three individual stakeholder meetings, one per each stakeholder group. In Phase 2, participants were brought together in a multi-stakeholder meeting to review findings of each stakeholder group, after which stakeholders repeated the weighting exercise as a collective group. All meetings included reflective discussion by participants of each value criteria/sub-criteria included within the adapted MCDA framework, where stakeholders shared their perspectives and opinions on what represents value in RCC|UCC. RESULTS: Refractory or unexplained chronic cough is regarded as a chronic medical condition, with variable severity across patients and the potential to heavily impact their HRQoL (including physical, psychological and social/work productivity domains). Current treatments used by healthcare professionals, which have not been specifically developed and are not approved for RCC|UCC, show limited clinical effectiveness and associated safety and tolerability issues, which result in frequent treatment discontinuations. The reduction of the average cough frequency over a 24-h period is regarded as the primary goal of treatment by stakeholders, with the aim of improving HRQoL. Improvement of other cough symptoms, such as intensity, is also considered important. Minor adverse events and a slower onset of treatment effect would be acceptable to stakeholders if accompanied by strong efficacy and improvement in HRQoL. Given the inability to measure cough frequency in clinical practice, Patient-Reported Outcomes (PROs) could be considered a proxy of treatment effectiveness. A multidisciplinary approach to the condition is regarded as key for treatment success. CONCLUSIONS: Refractory or unexplained chronic cough is a medical condition that seriously impacts patients' HRQoL. The primary goal of treatment is to improve patients' HRQoL by reducing the frequency and intensity of cough.

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.

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.

Evaluation of Antineoplastic Delayed-Type Hypersensitivity Skin Reactions In Vitro.

Delayed-type hypersensitivity (DTH) is caused by a broad number of drugs used in clinic, and antineoplastic drugs show an elevated proportion of DTH, which potentially affects the quality of life of patients. Despite the serious problem and the negative economic impact deriving from market withdrawal of such drugs and high hospitalization costs, nowadays, there are no standard validated methods in vitro or in vivo to evaluate the sensitizing potential of drugs in the preclinical phase. Enhanced predictions in preclinical safety evaluations are really important, and for that reason, the aim of our work is to adapt in vitro DPRA, ARE-Nrf2 luciferase KeratinoSensTM, and hCLAT assays for the study of the sensitizing potential of antineoplastic agents grouped by mechanism of action. Our results reveal that the above tests are in vitro techniques able to predict the sensitizing potential of the tested antineoplastics. Moreover, this is the first time that the inhibition of the VEGFR1 pathway has been identified as a potential trigger of DTH.

Paclitaxel Induces Epidermal Molecular Changes and Produces Subclinical Alterations in the Skin of Gynecological Cancer Patients.

BACKGROUND: Paclitaxel is a microtubule-stabilizing chemotherapeutic agent. Despite its widespread use, it damages healthy tissues such as skin. The goal of this study was to prove that the real impact of paclitaxel-induced skin toxicity could be underestimated because the adverse events might appear asymptomatic. METHODS: Gynecological cancer patients were recruited. Skin parameters measurements were taken after three and six paclitaxel cycles. Measurements were conducted using specific probes which measure hydration, transepidermal water loss (TEWL), sebum, elasticity and firmness, erythema, roughness, smoothness, skin thickness, and desquamation levels. Further, a 3D epidermis model was incubated with paclitaxel to analyze gene and protein expression of aquaporin 3, collagen type 1, elastin, and fibronectin. RESULTS: Paclitaxel induced alterations in the skin parameters with no visible clinical manifestations. Gynecological cancer patients under paclitaxel treatment had a decrease in hydration, TEWL, sebum, elasticity, and thickness of the skin, while erythema, roughness, and desquamation were increased. The molecular markers, related to hydration and the support of the skin layers, and analyzed in the 3D epidermis model, were decreased. CONCLUSIONS: Results suggest that paclitaxel modifies gene and protein expression of skin-related molecular markers, and impairs different physical, physiological, and biomechanical properties of the skin of cancer patients at a subclinical level.

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.

Senescence Alterations in Pulmonary Hypertension.

Cellular senescence is the arrest of normal cell division and is commonly associated with aging. The interest in the role of cellular senescence in lung diseases derives from the observation of markers of senescence in chronic obstructive pulmonary disease (COPD), pulmonary fibrosis (IPF), and pulmonary hypertension (PH). Accumulation of senescent cells and the senescence-associated secretory phenotype in the lung of aged patients may lead to mild persistent inflammation, which results in tissue damage. Oxidative stress due to environmental exposures such as cigarette smoke also promotes cellular senescence, together with additional forms of cellular stress such as mitochondrial dysfunction and endoplasmic reticulum stress. Growing recent evidence indicate that senescent cell phenotypes are observed in pulmonary artery smooth muscle cells and endothelial cells of patients with PH, contributing to pulmonary artery remodeling and PH development. In this review, we analyze the role of different senescence cell phenotypes contributing to the pulmonary artery remodeling process in different PH clinical entities. Different molecular pathway activation and cellular functions derived from senescence activation will be analyzed and discussed as promising targets to develop future senotherapies as promising treatments to attenuate pulmonary artery remodeling in PH.

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.

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.

Nitric Oxide System and Bronchial Epithelium: More Than a Barrier.

Airway epithelium forms a physical barrier that protects the lung from the entrance of inhaled allergens, irritants, or microorganisms. This epithelial structure is maintained by tight junctions, adherens junctions and desmosomes that prevent the diffusion of soluble mediators or proteins between apical and basolateral cell surfaces. This apical junctional complex also participates in several signaling pathways involved in gene expression, cell proliferation and cell differentiation. In addition, the airway epithelium can produce chemokines and cytokines that trigger the activation of the immune response. Disruption of this complex by some inflammatory, profibrotic, and carcinogens agents can provoke epithelial barrier dysfunction that not only contributes to an increase of viral and bacterial infection, but also alters the normal function of epithelial cells provoking several lung diseases such as asthma, chronic obstructive pulmonary disease (COPD), cystic fibrosis (CF) or lung cancer, among others. While nitric oxide (NO) molecular pathway has been linked with endothelial function, less is known about the role of the NO system on the bronchial epithelium and airway epithelial cells function in physiological and different pathologic scenarios. Several data indicate that the fraction of exhaled nitric oxide (FENO) is altered in lung diseases such as asthma, COPD, lung fibrosis, and cancer among others, and that reactive oxygen species mediate uncoupling NO to promote the increase of peroxynitrite levels, thus inducing bronchial epithelial barrier dysfunction. Furthermore, iNOS and the intracellular pathway sGC-cGMP-PKG are dysregulated in bronchial epithelial cells from patients with lung inflammation, fibrosis, and malignancies which represents an attractive drug molecular target. In this review we describe in detail current knowledge of the effect of NOS-NO-GC-cGMP-PKG pathway activation and disruption in bronchial epithelial cells barrier integrity and its contribution in different lung diseases, focusing on bronchial epithelial cell permeability, inflammation, transformation, migration, apoptosis/necrosis, and proliferation, as well as the specific NO molecular pathways involved.

The role of mucin 1 in respiratory diseases.

Recent evidence has demonstrated that mucin 1 (MUC1) is involved in many pathological processes that occur in the lung. MUC1 is a transmembrane protein mainly expressed by epithelial and hematopoietic cells. It has a receptor-like structure, which can sense the external environment and activate intracellular signal transduction pathways through its cytoplasmic domain. The extracellular domain of MUC1 can be released to the external environment, thus acting as a decoy barrier to mucosal pathogens, as well as serving as a serum biomarker for the diagnosis and prognosis of several respiratory diseases such as lung cancer and interstitial lung diseases. Furthermore, bioactivated MUC1-cytoplasmic tail (CT) has been shown to act as an anti-inflammatory molecule in several airway infections and mediates the expression of anti-inflammatory genes in lung diseases such as chronic rhinosinusitis, chronic obstructive pulmonary disease and severe asthma. Bioactivated MUC1-CT has also been reported to interact with several effectors linked to cellular transformation, contributing to the progression of respiratory diseases such as lung cancer and pulmonary fibrosis. In this review, we summarise the current knowledge of MUC1 as a promising biomarker and drug target for lung disease.