Impaired TRIM16-Mediated Lysophagy in Chronic Obstructive Pulmonary Disease Pathogenesis.

Insufficient autophagic degradation has been implicated in accelerated cellular senescence during chronic obstructive pulmonary disease (COPD) pathogenesis. Aging-linked and cigarette smoke (CS)-induced functional deterioration of lysosomes may be associated with impaired autophagy. Lysosomal membrane permeabilization (LMP) is indicative of damaged lysosomes. Galectin-3 and tripartite motif protein (TRIM) 16 play a cooperative role in recognizing LMP and inducing lysophagy, a lysosome-selective autophagy, to maintain lysosome function. In this study, we sought to examine the role of TRIM16-mediated lysophagy in regulating CS-induced LMP and cellular senescence during COPD pathogenesis by using human bronchial epithelial cells and lung tissues. CS extract (CSE) induced lysosomal damage via LMP, as detected by galectin-3 accumulation. Autophagy was responsible for modulating LMP and lysosome function during CSE exposure. TRIM16 was involved in CSE-induced lysophagy, with impaired lysophagy associated with lysosomal dysfunction and accelerated cellular senescence. Airway epithelial cells in COPD lungs showed an increase in lipofuscin, aggresome and galectin-3 puncta, reflecting accumulation of lysosomal damage with concomitantly reduced TRIM16 expression levels. Human bronchial epithelial cells isolated from COPD patients showed reduced TRIM16 but increased galectin-3, and a negative correlation between TRIM16 and galectin-3 protein levels was demonstrated. Damaged lysosomes with LMP are accumulated in epithelial cells in COPD lungs, which can be at least partly attributed to impaired TRIM16-mediated lysophagy. Increased LMP in lung epithelial cells may be responsible for COPD pathogenesis through the enhancement of cellular senescence.

Effects of CYP3A4/5 and ABC transporter polymorphisms on osimertinib plasma concentrations in Japanese patients with non-small cell lung cancer.

The effects of polymorphisms in CYP3A4 (20230G > A), CYP3A5 (6986A > G), ABCB1 (1236C > T, 2677G > T/A, 3435C > T), ABCG2 (421C > A), and ABCC2 (-24C > T) on the area under the concentration-time curve (AUC) of osimertinib in 23 patients with non-small cell lung cancer were investigated. Blood sampling was performed just prior to and at 1, 2, 4, 6, 8, 12, and 24 h after osimertinib administration at the steady-state on day 15 after beginning therapy. The osimertinib AUC0-24 was significantly correlated with age (P = 0.038), serum albumin (P = 0.002), and serum creatinine (P = 0.012). Additionally, there were significant differences in the AUC0-24 of osimertinib among the groups administered vonoprazan, histamine 2-receptor antagonists or esomeprazole, and no acid suppressants (P = 0.021). By contrast, there were no significant differences in the AUC0-24 of osimertinib between genotypes of CYP3A4/5 or ABC transporters. Furthermore, there were no significant differences in the AUC0-24 of osimertinib between patients with diarrhea, skin rash, or hepatotoxicity and those without these conditions. In multivariate analysis, only serum albumin value was an independent factor predicting the AUC0-24 of osimertinib. Analysis of CYP3A4/5 and ABC transporter polymorphisms before osimertinib therapy may not predict the efficacy or side effects of osimertinib. The lower serum albumin values were associated with an increase in the AUC0-24 of osimertinib; however, further studies are needed to assess the factors contributing to the interindividual variability of osimertinib pharmacokinetics.

Chaperone-Mediated Autophagy Suppresses Apoptosis via Regulation of the Unfolded Protein Response during Chronic Obstructive Pulmonary Disease Pathogenesis.

Cigarette smoke (CS) induces accumulation of misfolded proteins with concomitantly enhanced unfolded protein response (UPR). Increased apoptosis linked to UPR has been demonstrated in chronic obstructive pulmonary disease (COPD) pathogenesis. Chaperone-mediated autophagy (CMA) is a type of selective autophagy for lysosomal degradation of proteins with the KFERQ peptide motif. CMA has been implicated in not only maintaining nutritional homeostasis but also adapting the cell to stressed conditions. Although recent papers have shown functional cross-talk between UPR and CMA, mechanistic implications for CMA in COPD pathogenesis, especially in association with CS-evoked UPR, remain obscure. In this study, we sought to examine the role of CMA in regulating CS-induced apoptosis linked to UPR during COPD pathogenesis using human bronchial epithelial cells (HBEC) and lung tissues. CS extract (CSE) induced LAMP2A expression and CMA activation through a Nrf2-dependent manner in HBEC. LAMP2A knockdown and the subsequent CMA inhibition enhanced UPR, including CHOP expression, and was accompanied by increased apoptosis during CSE exposure, which was reversed by LAMP2A overexpression. Immunohistochemistry showed that Nrf2 and LAMP2A levels were reduced in small airway epithelial cells in COPD compared with non-COPD lungs. Both Nrf2 and LAMP2A levels were significantly reduced in HBEC isolated from COPD, whereas LAMP2A levels in HBEC were positively correlated with pulmonary function tests. These findings suggest the existence of functional cross-talk between CMA and UPR during CSE exposure and also that impaired CMA may be causally associated with COPD pathogenesis through enhanced UPR-mediated apoptosis in epithelial cells.

Involvement of GPx4-Regulated Lipid Peroxidation in Idiopathic Pulmonary Fibrosis Pathogenesis.

The imbalanced redox status in lung has been widely implicated in idiopathic pulmonary fibrosis (IPF) pathogenesis. To regulate redox status, hydrogen peroxide must be adequately reduced to water by glutathione peroxidases (GPx). Among GPx isoforms, GPx4 is a unique antioxidant enzyme that can directly reduce phospholipid hydroperoxide. Increased lipid peroxidation products have been demonstrated in IPF lungs, suggesting the participation of imbalanced lipid peroxidation in IPF pathogenesis, which can be modulated by GPx4. In this study, we sought to examine the involvement of GPx4-modulated lipid peroxidation in regulating TGF-ß-induced myofibroblast differentiation. Bleomycin-induced lung fibrosis development in mouse models with genetic manipulation of GPx4 were examined. Immunohistochemical evaluations for GPx4 and lipid peroxidation were performed in IPF lung tissues. Immunohistochemical evaluations showed reduced GPx4 expression levels accompanied by increased 4-hydroxy-2-nonenal in fibroblastic focus in IPF lungs. TGF-ß-induced myofibroblast differentiation was enhanced by GPx4 knockdown with concomitantly enhanced lipid peroxidation and SMAD2/SMAD3 signaling. Heterozygous GPx4-deficient mice showed enhancement of bleomycin-induced lung fibrosis, which was attenuated in GPx4-transgenic mice in association with lipid peroxidation and SMAD signaling. Regulating lipid peroxidation by Trolox showed efficient attenuation of bleomycin-induced lung fibrosis development. These findings suggest that increased lipid peroxidation resulting from reduced GPx4 expression levels may be causally associated with lung fibrosis development through enhanced TGF-ß signaling linked to myofibroblast accumulation of fibroblastic focus formation during IPF pathogenesis. It is likely that regulating lipid peroxidation caused by reduced GPx4 can be a promising target for an antifibrotic modality of treatment for IPF.

Involvement of Lamin B1 Reduction in Accelerated Cellular Senescence during Chronic Obstructive Pulmonary Disease Pathogenesis.

Downregulation of lamin B1 has been recognized as a crucial step for development of full senescence. Accelerated cellular senescence linked to mechanistic target of rapamycin kinase (MTOR) signaling and accumulation of mitochondrial damage has been implicated in chronic obstructive pulmonary disease (COPD) pathogenesis. We hypothesized that lamin B1 protein levels are reduced in COPD lungs, contributing to the process of cigarette smoke (CS)-induced cellular senescence via dysregulation of MTOR and mitochondrial integrity. To illuminate the role of lamin B1 in COPD pathogenesis, lamin B1 protein levels, MTOR activation, mitochondrial mass, and cellular senescence were evaluated in CS extract (CSE)-treated human bronchial epithelial cells (HBEC), CS-exposed mice, and COPD lungs. We showed that lamin B1 was reduced by exposure to CSE and that autophagy was responsible for lamin B1 degradation in HBEC. Lamin B1 reduction was linked to MTOR activation through DEP domain-containing MTOR-interacting protein (DEPTOR) downregulation, resulting in accelerated cellular senescence. Aberrant MTOR activation was associated with increased mitochondrial mass, which can be attributed to peroxisome proliferator-activated receptor γ coactivator-1ß-mediated mitochondrial biogenesis. CS-exposed mouse lungs and COPD lungs also showed reduced lamin B1 and DEPTOR protein levels, along with MTOR activation accompanied by increased mitochondrial mass and cellular senescence. Antidiabetic metformin prevented CSE-induced HBEC senescence and mitochondrial accumulation via increased DEPTOR expression. These findings suggest that lamin B1 reduction is not only a hallmark of lung aging but is also involved in the progression of cellular senescence during COPD pathogenesis through aberrant MTOR signaling.

ABCG2 C421A polymorphisms affect exposure of the epidermal growth factor receptor inhibitor gefitinib.

ATP-binding castle protein G2 (ABCG2) is thought to inhibit the activities of certain gefitinib transporters, thereby affecting drug pharmacokinetics. The C421A polymorphism affects the function and expression of ABCG2 on the cell membrane. Previous studies have shown that proton-pump inhibitors (PPIs) inhibit gefitinib absorption, as well as the function of ABCG2. We evaluated the plasma concentrations of gefitinib in patients with and without the ABCG2 C421A polymorphism, who were or were not taking PPIs. In total, 61 patients with advanced epidermal-growth-factor-positive non-small-cell lung cancer were enrolled in this study. They were treated with gefitinib at a dose of 250 mg per day. Plasma gefitinib concentration and ABCG2 C421A status were determined after 2 weeks. The patients were divided into CC- and CA/AA genotype groups. We compared the trough and peak gefitinib levels and the area under the curve (AUC) values for 24-h gefitinib concentrations. We also compared these parameters among four groups distinguished according to the presence or absence of the polymorphism and PPI use. The mean trough gefitinib level and AUC value for 24-h gefitinib concentration were significantly lower in the CA/AA group compared to the CC group (mean trough level: 333.2 vs. 454.5 ng/mL, respectively, P = 0.021; AUC: 9949.9 vs. 13,085.4 ng・h/mL, respectively, P = 0.034). Among patients taking PPIs, the mean trough gefitinib level was significantly lower in the CA/AA group than the CC group (220.1 vs. 340.5 ng/mL, respectively, P = 0.033). The CA/AA-type of ABCG2 C421A polymorphism may be associated with lower gefitinib plasma concentrations.

Effects of STAT3 polymorphisms and pharmacokinetics on the clinical outcomes of gefitinib treatment in patients with EGFR-mutation positive non-small cell lung cancer.

WHAT IS KNOWN AND OBJECTIVE: We investigated the correlations among signal transducer and activator of transcription 3 (STAT3) rs4796793C >G polymorphism, gefitinib pharmacokinetics and clinical responses in Japanese patients with non-small cell lung cancer receiving gefitinib therapy. METHODS: Forty-five patients were enrolled in this study. Plasma trough concentrations (C0 ) of gefitinib at the steady-state were measured by high-performance liquid chromatography. RESULTS AND DISCUSSION: Patients having a gefitinib C0 of at least ≥200 ng/mL had significantly longer PFS than patients having a C0 of <200 ng/mL (median [95% confidence interval (CI)] PFS: 11.0 [8.2-13.7] and 5.3 [0.0-12.0] months, respectively, P = .042). There were no significant differences in PFS between patients with STAT3 rs4796793C/C and G alleles; however, patients with STAT3 rs4796793C/C having a gefitinib C0 of ≥ 200 ng/mL had significantly longer progression-free survival (PFS) and overall survival (OS) than those with a C0 of <200 ng/mL (median [95% CI] PFS: 11.4 [4.1-18.6] and 3.0 [0.0-7.0] months, respectively, P = .008; median [95% CI] OS: 20.6 [7.4-33.7] and 12.6 [10.1-15.1] months, respectively, P = .042). In patients with the STAT3 rs4796793G allele, there were no significant differences in PFS and OS between the two gefitinib C0 groups. In addition, there were no significant differences in PFS or OS according to smoking, presence of proton pump inhibitor combination, or onset of side effects. WHAT IS NEW AND CONCLUSION: Clinical outcomes of gefitinib in patients with the STAT3 rs4796793C/C genotype depended on plasma concentrations of gefitinib. In addition to information regarding EGFR mutations, the STAT3 rs4796793C >G polymorphism and gefitinib C0 may be potential predictors of clinical outcomes after beginning of gefitinib therapy.

Clinical benefits of adjuvant chemotherapy with carboplatin and gemcitabine in patients with non-small cell lung cancer: a single-center retrospective study.

PURPOSE: In cases of non-small cell lung cancer (NSCLC), surgery remains the best option for cure, but surgery is of benefit only when the disease is localized. Although adjuvant chemotherapy reportedly has a significant beneficial effect on survival, the benefit of a carboplatin (CBDCA) regimen is unclear. We therefore investigated the efficacy and tolerability of CBDCA (area under the curve 5) plus gemcitabine (GEM, 1000 mg/m2) as adjuvant chemotherapy. METHODS: A total of 82 pStage IB-IIIA NSCLC patients who had undergone complete resection and received adjuvant chemotherapy were analyzed retrospectively. Among them, 65 patients received CBDCA + GEM and 17 received CDDP + VNR. Propensity score analysis generated 17 matched pairs of both groups. RESULTS: Sixty-five patients received CBDCA + GEM. Their 5-year relapse-free survival (RFS) and overall survival were 47.8% (median, 52.5 months) and 76.9% (median, 90.1 months), respectively. Toxicities, which included neutropenia, nausea/anorexia, fatigue, and vasculitis, were significantly milder than with CDDP + VNR. There were no significant differences in RFS between CBDCA + GEM and CDDP + VNR (p = 0.079) after matching for age, performance status, and pStage. CONCLUSION: CBDCA + GEM was effective and well tolerated as adjuvant chemotherapy, with a manageable toxicity profile.

Efficacy of mepolizumab for patients with severe asthma and eosinophilic chronic rhinosinusitis.

BACKGROUND: Several major randomized control studies have demonstrated that mepolizumab, an anti-IL-5 monoclonal antibody, is effective for patients with severe eosinophilic asthma who show exacerbation or require systemic corticosteroid maintenance therapy. However, the predictive factors of the response to mepolizumab other than blood eosinophil count are unclear in clinical practice. OBJECTIVE: To elucidate the predictive factors of the response to mepolizumab for patients with severe eosinophilic asthma. METHODS: From July 2016 to December 2017, 28 patients with severe asthma received mepolizumab in our hospital. To determine the predictive factors, we retrospectively evaluated patient characteristics, comorbidities, biomarkers, pulmonary function, maintenance dose of systemic corticosteroids and number of exacerbations. RESULTS: The response rate to mepolizumab treatment was 70% (19/27; one pregnant woman was excluded from analysis). Compared with 11 patients without eosinophilic chronic rhinosinusitis (ECRS), 16 patients with ECRS showed significantly improved systemic corticosteroid-sparing effects [- 71.3 ± 37.0% vs - 10.7 ± 20.1%, P = 0.006], change from baseline FeNO [- 19 ± 57 (%) vs 30 ± 77 (%), P = 0.023] and symptoms [14 patients (88%) vs five patients (45%), P = 0.033]. ECRS was identified as a predictive factor of the response to mepolizumab in a multivariate logistic regression analysis [odds ratio = 22.5, 95% CI (1.5-336), P = 0.024]. Of the eight patients previously administered omalizumab, five responded to mepolizumab. Staphylococcus aureus enterotoxin B IgE results were negative in 80% of responders (P = 0.14). CONCLUSION: Both groups showed improved symptom scores and a decreased number of exacerbations. Mepolizumab substantially improved the clinical variables of patients with eosinophilic asthma complicated with ECRS.

Phase II trial of induction chemotherapy with carboplatin and paclitaxel plus bevacizumab in patients with stage IIIA to IV nonsquamous non-small cell lung cancer.

PURPOSE: Surgery remains the best curative treatment option for non-small cell lung cancer (NSCLC), but is of benefit only to patients with localized disease. A meta-analysis showed a significant beneficial effect of induction chemotherapy on survival, but there is still no clear evidence. This phase II study was conducted to establish whether induction chemotherapy with carboplatin (CBDCA) and paclitaxel (PTX) plus bevacizumab prior to surgery reduces the risk of progression. METHODS: The subjects of this study were 29 patients with treatment-naive nonsquamous NSCLC (clinical stages IIIA to IV). Patients received PTX (200 mg/m2), CBDCA (area under the curve, 5), and bevacizumab (15 mg/kg) followed by surgery. Chemotherapy was repeated every 3 weeks for up to six cycles. RESULTS: The overall response rate was 72.4%. Of the 29 patients, ten underwent surgery after the induction chemotherapy and complete resection was achieved in 7 (70%). The median progression-free-survival (PFS) time and the 3-year PFS rate were 0.92 years and 16.2%, respectively. The median overall survival (OS) time and the 3-year OS rate were 1.96 years and 44.9%, respectively. CONCLUSION: Combined modality therapy with surgery after induction chemotherapy with CBDCA and PTX plus bevacizumab is clinically feasible and tolerable for patients with unknown or negative molecular profiles.

Involvement of PARK2-Mediated Mitophagy in Idiopathic Pulmonary Fibrosis Pathogenesis.

Fibroblastic foci, known to be the leading edge of fibrosis development in idiopathic pulmonary fibrosis (IPF), are composed of fibrogenic myofibroblasts. Autophagy has been implicated in the regulation of myofibroblast differentiation. Insufficient mitophagy, the mitochondria-selective autophagy, results in increased reactive oxygen species, which may modulate cell signaling pathways for myofibroblast differentiation. Therefore, we sought to investigate the regulatory role of mitophagy in myofibroblast differentiation as a part of IPF pathogenesis. Lung fibroblasts were used in in vitro experiments. Immunohistochemical evaluation in IPF lung tissues was performed. PARK2 was examined as a target molecule for mitophagy regulation, and a PARK2 knockout mouse was employed in a bleomycin-induced lung fibrosis model. We demonstrated that PARK2 knockdown-mediated mitophagy inhibition was involved in the mechanism for activation of the platelet-derived growth factor receptor (PDGFR)/PI3K/AKT signaling pathway accompanied by enhanced myofibroblast differentiation and proliferation, which were clearly inhibited by treatment with both antioxidants and AG1296, a PDGFR inhibitor. Mitophagy inhibition-mediated activation of PDGFR signaling was responsible for further autophagy suppression, suggesting the existence of a self-amplifying loop of mitophagy inhibition and PDGFR activation. IPF lung demonstrated reduced PARK2 with concomitantly increased PDGFR phosphorylation. Furthermore, bleomycin-induced lung fibrosis was enhanced in PARK2 knockout mice and subsequently inhibited by AG1296. These findings suggest that insufficient mitophagy-mediated PDGFR/PI3K/AKT activation, which is mainly attributed to reduced PARK2 expression, is a potent underlying mechanism for myofibroblast differentiation and proliferation in fibroblastic foci formation during IPF pathogenesis.

Risk factors of postoperative pulmonary complications in patients with asthma and COPD.

BACKGROUND: Postoperative pulmonary complications (PPC) in patients with pulmonary diseases remain to be resolved clinical issue. However, most evidence regarding PPC has been established more than 10 years ago. Therefore, it is necessary to evaluate perioperative management using new inhalant drugs in patients with obstructive pulmonary diseases. METHODS: April 2014 through March 2015, 346 adult patients with pulmonary diseases (257 asthma, 89 chronic obstructive pulmonary disease (COPD)) underwent non-pulmonary surgery except cataract surgery in our university hospital. To analyze the risk factors for PPC, we retrospectively evaluated physiological backgrounds, surgical factors and perioperative specific treatment for asthma and COPD. RESULTS: Finally, 29 patients with pulmonary diseases (22 asthma, 7 COPD) had PPC. In patients with asthma, smoking index (≥ 20 pack-years), peripheral blood eosinophil count (≥ 200/mm3) and severity (Global INitiative for Asthma(GINA) STEP ≥ 3) were significantly associated with PPC in the multivariate logistic regression analysis [odds ratio (95% confidence interval) = 5.4(1.4-20.8), 0.31 (0.11-0.84) and 3.2 (1.04-9.9), respectively]. In patients with COPD, age, introducing treatment for COPD, upper abdominal surgery and operation time (≥ 5 h) were significantly associated with PPC [1.18 (1.00-1.40), 0.09 (0.01-0.81), 21.2 (1.3-349) and 9.5 (1.2-77.4), respectively]. CONCLUSIONS: History of smoking or severe asthma is a risk factor of PPC in patients with asthma, and age, upper abdominal surgery, or long operation time is a risk factor of PPC in patients with COPD. Adequate inhaled corticosteroids treatment in patients with eosinophilic asthma and introducing treatment for COPD in patients with COPD could reduce PPCs.

Pirfenidone inhibits myofibroblast differentiation and lung fibrosis development during insufficient mitophagy.

BACKGROUND: Pirfenidone (PFD) is an anti-fibrotic agent used to treat idiopathic pulmonary fibrosis (IPF), but its precise mechanism of action remains elusive. Accumulation of profibrotic myofibroblasts is a crucial process for fibrotic remodeling in IPF. Recent findings show participation of autophagy/mitophagy, part of the lysosomal degradation machinery, in IPF pathogenesis. Mitophagy has been implicated in myofibroblast differentiation through regulating mitochondrial reactive oxygen species (ROS)-mediated platelet-derived growth factor receptor (PDGFR) activation. In this study, the effect of PFD on autophagy/mitophagy activation in lung fibroblasts (LF) was evaluated, specifically the anti-fibrotic property of PFD for modulation of myofibroblast differentiation during insufficient mitophagy. METHODS: Transforming growth factor-ß (TGF-ß)-induced or ATG5, ATG7, and PARK2 knockdown-mediated myofibroblast differentiation in LF were used for in vitro models. The anti-fibrotic role of PFD was examined in a bleomycin (BLM)-induced lung fibrosis model using PARK2 knockout (KO) mice. RESULTS: We found that PFD induced autophagy/mitophagy activation via enhanced PARK2 expression, which was partly involved in the inhibition of myofibroblast differentiation in the presence of TGF-ß. PFD inhibited the myofibroblast differentiation induced by PARK2 knockdown by reducing mitochondrial ROS and PDGFR-PI3K-Akt activation. BLM-treated PARK2 KO mice demonstrated augmentation of lung fibrosis and oxidative modifications compared to those of BLM-treated wild type mice, which were efficiently attenuated by PFD. CONCLUSIONS: These results suggest that PFD induces PARK2-mediated mitophagy and also inhibits lung fibrosis development in the setting of insufficient mitophagy, which may at least partly explain the anti-fibrotic mechanisms of PFD for IPF treatment.

Detection of pathogens by real-time PCR in adult patients with acute exacerbation of bronchial asthma.

BACKGROUND: Respiratory tract infection is a major cause of acute exacerbation of bronchial asthma (AEBA). Although recent findings suggest that common bacteria are causally associated with AEBA, a comprehensive epidemiologic analysis of infectious pathogens including common/atypical bacteria and viruses in AEBA has not been performed. Accordingly, we attempted to detect pathogens during AEBA by using real-time polymerase chain reaction (PCR) in comparison to conventional methods. METHODS: We prospectively enroled adult patients with AEBA from August 2012 to March 2014. Infectious pathogens collected in nasopharyngeal swab and sputum samples were examined in each patient by conventional methods and real-time PCR, which can detect 6 bacterial and 11 viral pathogens. The causal association of these pathogens with AEBA severity and their frequency of monthly distribution were also examined. RESULTS: Among the 64 enroled patients, infectious pathogens were detected in 49 patients (76.6%) using real-time PCR and in 14 patients (21.9%) using conventional methods (p < 0.001). Real-time PCR detected bacteria in 29 patients (45.3%) and respiratory viruses in 28 patients (43.8%). Haemophilus influenzae was the most frequently detected microorganism (26.6%), followed by rhinovirus (15.6%). Influenza virus was the significant pathogen associated with severe AEBA. Moreover, AEBA occurred most frequently during November to January. CONCLUSIONS: Real-time PCR was more useful than conventional methods to detect infectious pathogens in patients with AEBA. Accurate detection of pathogens with real-time PCR may enable the selection of appropriate anti-bacterial/viral agents as a part of the treatment for AEBA.

Metformin attenuates lung fibrosis development via NOX4 suppression.

BACKGROUND: Accumulation of profibrotic myofibroblasts in fibroblastic foci (FF) is a crucial process for development of fibrosis during idiopathic pulmonary fibrosis (IPF) pathogenesis, and transforming growth factor (TGF)-ß plays a key regulatory role in myofibroblast differentiation. Reactive oxygen species (ROS) has been proposed to be involved in the mechanism for TGF-ß-induced myofibroblast differentiation. Metformin is a biguanide antidiabetic medication and its pharmacological action is mediated through the activation of AMP-activated protein kinase (AMPK), which regulates not only energy homeostasis but also stress responses, including ROS. Therefore, we sought to investigate the inhibitory role of metformin in lung fibrosis development via modulating TGF-ß signaling. METHODS: TGF-ß-induced myofibroblast differentiation in lung fibroblasts (LF) was used for in vitro models. The anti-fibrotic role of metfromin was examined in a bleomycin (BLM)-induced lung fibrosis model. RESULTS: We found that TGF-ß-induced myofibroblast differentiation was clearly inhibited by metformin treatment in LF. Metformin-mediated activation of AMPK was responsible for inhibiting TGF-ß-induced NOX4 expression. NOX4 knockdown and N-acetylcysteine (NAC) treatment illustrated that NOX4-derived ROS generation was critical for TGF-ß-induced SMAD phosphorylation and myofibroblast differentiation. BLM treatment induced development of lung fibrosis with concomitantly enhanced NOX4 expression and SMAD phosphorylation, which was efficiently inhibited by metformin. Increased NOX4 expression levels were also observed in FF of IPF lungs and LF isolated from IPF patients. CONCLUSIONS: These findings suggest that metformin can be a promising anti-fibrotic modality of treatment for IPF affected by TGF-ß.

Autophagy induction by SIRT6 through attenuation of insulin-like growth factor signaling is involved in the regulation of human bronchial epithelial cell senescence.

Cigarette smoke (CS)-induced cellular senescence has been implicated in the pathogenesis of chronic obstructive pulmonary disease, and SIRT6, a histone deacetylase, antagonizes this senescence, presumably through the attenuation of insulin-like growth factor (IGF)-Akt signaling. Autophagy controls cellular senescence by eliminating damaged cellular components and is negatively regulated by IGF-Akt signaling through the mammalian target of rapamycin (mTOR). SIRT1, a representative sirtuin family, has been demonstrated to activate autophagy, but a role for SIRT6 in autophagy activation has not been shown. Therefore, we sought to investigate the regulatory role for SIRT6 in autophagy activation during CS-induced cellular senescence. SIRT6 expression levels were modulated by cDNA and small interfering RNA transfection in human bronchial epithelial cells (HBECs). Senescence-associated ß-galactosidase staining and Western blotting of p21 were performed to evaluate senescence. We demonstrated that SIRT6 expression levels were decreased in lung homogenates from chronic obstructive pulmonary disease patients, and SIRT6 expression levels correlated significantly with the percentage of forced expiratory volume in 1 s/forced vital capacity. CS extract (CSE) suppressed SIRT6 expression in HBECs. CSE-induced HBEC senescence was inhibited by SIRT6 overexpression, whereas SIRT6 knockdown and mutant SIRT6 (H133Y) without histone deacetylase activity enhanced HBEC senescence. SIRT6 overexpression induced autophagy via attenuation of IGF-Akt-mTOR signaling. Conversely, SIRT6 knockdown and overexpression of a mutant SIRT6 (H133Y) inhibited autophagy. Autophagy inhibition by knockdown of ATG5 and LC3B attenuated the antisenescent effect of SIRT6 overexpression. These results suggest that SIRT6 is involved in CSE-induced HBEC senescence via autophagy regulation, which can be attributed to attenuation of IGF-Akt-mTOR signaling.

Clinical efficacy of anti-glycopeptidolipid-core IgA test for diagnosing Mycobacterium avium complex infection in lung.

BACKGROUND AND OBJECTIVE: It is difficult to verify the bacteriological diagnosis of Mycobacterium avium complex (MAC) infection. The anti-glycopeptidolipid (GPL)-core IgA antibody test was recently developed as a diagnostic method for MAC pulmonary disease. Only a few studies evaluate its clinical efficacy. We conducted retrospective evaluations of clinical characteristics of patients suspected of MAC infection to explore the usefulness of the anti-GPL-core IgA antibody test. METHODS: We retrospectively evaluated 296 patients who were suspected to have MAC infection and underwent anti-GPL-core IgA antibody test between March 2013 and July 2014 in Jikei University hospital. RESULTS: A total of 29 patients were diagnosed with 'definite MAC' based on the American Thoracic Society (ATS) criteria with multiple identifications of MAC. On the other hand, 106 patients were diagnosed with other pulmonary diseases than MAC. The sensitivity and specificity of anti-GPL-core IgA antibody test for MAC diagnosis were 58.6% and 98.1%, respectively. The definite MAC group showed no significant differences in strains, treatment history or number of segments involved. The duration of MAC disease in the positive-antibody group was significantly longer than in the negative-antibody group (P = 0.046). A significant increase in the false-negative rate was observed in patients with malignant disease (P = 0.029). CONCLUSIONS: The anti-GPL-core IgA antibody test demonstrated high sensitivity and specificity for the diagnosis of MAC infection especially in patients without malignant diseases.

Effectiveness of neuromuscular electrical stimulation in patients with acute exacerbation of chronic obstructive pulmonary disease: A systematic review and meta-analysis.

BACKGROUND AND PURPOSE: This study aimed to investigate the effectiveness and acceptability of neuromuscular electrical stimulation (NMES) in patients with acute exacerbation of chronic obstructive pulmonary disease (COPD). METHODS: We conducted a systematic review and meta-analysis to investigate the effectiveness and accessibility of NMES and compared them with usual care in patients with acute exacerbation of COPD by searching databases such as MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials published up to April 2022. Randomized controlled trials (RCTs) involving patients with COPD who were treated within 3 weeks of acute exacerbation onset were included. The risk of bias was assessed using the RoB 2 tools. We pooled limb muscle strength and adverse events and performed a comparison between NMES and usual care. The quality of evidence was assessed using the Grading of Recommendations, Assessment, Development, and Evaluation approach. RESULTS: Five RCTs, including 168 patients, met the eligibility criteria. The meta-analysis showed that limb muscle strength was significantly higher in the NMES group (four studies with 148 patients; standardized mean difference, 0.95; 95% confidence interval, 0.60-1.30; p < 0.001). The quality of evidence was very low due to the risk of bias within the studies, imprecision of the estimates, and small number of studies. Any adverse events served as outcomes in three studies (86 patients), although no adverse events occurred. CONCLUSION: NMES is safe for patients with acute exacerbation of COPD and may maintain and improve limb muscle strength; however, the quality of evidence was very low.