Kunihiro Suzuki

Neutrophil elastase inhibitor sivelestat ameliorates gefitinib-naphthalene-induced acute pneumonitis in mice

Gefitinib, an epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI), is an effective therapeutic agent for non-small cell lung cancer with EGFR mutations. It can cause severe acute pneumonitis in some patients. We previously demonstrated that mice with naphthalene-induced airway epithelial injury developed severe gefitinib-induced pneumonitis and that neutrophils played important roles in the development of the disease. This study aimed to investigate the effects of the neutrophil elastase inhibitor sivelestat on gefitinib-induced pneumonitis in mice. C57BL/6J mice received naphthalene (200xa0mg/kg) intraperitoneally on day 0. Gefitinib (250 or 300xa0mg/kg) was orally administered to mice from dayxa0-1 until day 13. Sivelestat (150xa0mg/kg) was administered intraperitoneally from day 1 until day 13. Bronchoalveolar lavage fluid (BALF) and lung tissues were sampled on day 14. Sivelestat treatment significantly reduced the protein level, neutrophil count, neutrophil elastase activity in BALF, and severity of histopathologic findings on day 14 for mice administered with 250xa0mg/kg of gefitinib. Moreover, sivelestat treatment significantly improved the survival of mice administered with 300xa0mg/kg of gefitinib. These results indicate that sivelestat is a promising therapeutic agent for severe acute pneumonitis caused by gefitinib.

Probucol attenuates hyperoxia-induced lung injury in mice

Hyperoxic lung injury is pathologically characterized by alveolar edema, interlobular septal edema, hyaline membrane disease, lung inflammation, and alveolar hemorrhage. Although the precise mechanism by which hyperoxia causes lung injury is not well defined, oxidative stress, epithelial cell death, and proinflammatory cytokines are thought to be involved. Probucol—a commercially available drug for treating hypercholesterolemia—has been suggested to have antioxidant and antiapoptotic effects. This study aimed to assess whether probucol could attenuate hyperoxic lung injury in mice. Mice were exposed to 95% O2 for 72 h, with or without pre-treatment with 130 μg/kg probucol intratracheally. Probucol treatment significantly decreased both the number of inflammatory cells in the bronchoalveolar lavage fluid and the degree of lung injury in hyperoxia-exposed mice. Probucol treatment reduced the number of cells positive for 8-hydroxyl-2′-deoxyguanosine or terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) and suppressed NF-κB activation, Bax expression, and caspase-9 activation in lung tissues from hyperoxia-exposed mice. These results suggest that probucol can reduce oxidative DNA damage, apoptotic cell death, and inflammation in lung tissues. Intratracheal administration of probucol may be a novel treatment for lung diseases induced by oxidative stress, such as hyperoxic lung injury and acute respiratory distress syndrome.

Amphiregulin suppresses epithelial cell apoptosis in lipopolysaccharide-induced lung injury in mice

BACKGROUND AND OBJECTIVEnAs a member of the epidermal growth factor family, amphiregulin contributes to the regulation of cell proliferation. Amphiregulin was reported to be upregulated in damaged lung tissues in patients with chronic obstructive pulmonary disease and asthma and in lung epithelial cells in a ventilator-associated lung injury model. In this study, we investigated the effect of amphiregulin on lipopolysaccharide (LPS)-induced acute lung injury in mice.nnnMETHODSnAcute lung injury was induced by intranasal instillation of LPS in female C57BL/6 mice, and the mice were given intraperitoneal injections of recombinant amphiregulin or phosphate-buffered saline 6 and 0.5xa0h before and 3xa0h after LPS instillation. The effect of amphiregulin on apoptosis and apoptotic pathways in a murine lung alveolar type II epithelial cell line (LA-4xa0cells) were examined using flow cytometry and western blotting, respectively.nnnRESULTSnRecombinant amphiregulin suppressed epithelial cell apoptosis in LPS-induced lung injury in mice. Western blotting revealed that amphiregulin suppressed epithelial cell apoptosis by inhibiting caspase-8 activity.nnnCONCLUSIONnAmphiregulin signaling may be a therapeutic target for LPS-induced lung injury treatment through its prevention of epithelial cell apoptosis.

Depletion of club cells attenuates bleomycin-induced lung injury and fibrosis in mice

BackgroundThe role of bronchiolar epithelial cells in the pathogenesis of pulmonary fibrosis has not been clarified. We previously demonstrated DNA damage in murine bronchioles in the early stages of bleomycin-induced pulmonary fibrosis that subsequently extended to alveolar cells at the advanced stages of the disease. Club cells are progenitor cells for bronchioles and are known to play protective roles against lung inflammation and damage. The aim of the present study was to elucidate the role of club cells in the development of pulmonary fibrosis.MethodsC57BL/6xa0J mice received naphthalene intraperitoneally on day −2 to deplete club cells and were given intratracheal bleomycin or a vehicle on day 0. Lung tissues were obtained on days 1, 7, and 14, and bronchoalveolar lavage was performed on day 14. Bronchiolar epithelial cells sampled by laser capture microdissection were analyzed by gene expression microarray analysis on day 14.ResultsClub cell depletion induced by naphthalene protected mice from bleomycin-induced lung injury and fibrosis. Bleomycin-triggered bronchiolar TGF-β1 expression was reduced. Gene expression microarray analysis revealed that genes associated with inflammatory response and chemokine activity were downregulated in the bleomycin-injured bronchiolar epithelium with club cell injury compared to that in bronchiolar epithelium without cell injury.ConclusionsClub cells are involved in the development of lung injury and fibrosis.

Bax-inhibiting peptide attenuates bleomycin-induced lung injury in mice

ABSTRACT Bax is a pro-apoptotic member of the Bcl-2 family of proteins, and plays a central role in mitochondria-dependent apoptosis. Several lines of evidence have implied that Bax is involved in both epithelial apoptosis and fibroblast proliferation in idiopathic pulmonary fibrosis; however, the mechanisms remain unknown. Bax-inhibiting peptide V5 (BIP-V5) exhibits membrane permeability and inhibits the activation of Bax. The purpose of this study was to investigate whether the control of Bax activity by BIP-V5 reduces the degree of bleomycin-induced lung injury. C57BL/6J mice were administered bleomycin and BIP-V5 intratracheally on day 0. Bronchoalveolar lavage fluid and lung tissue were obtained on day 7. Human pulmonary alveolar epithelial cells (A549 cells) and mouse pulmonary alveolar epithelial cells (LA-4 cells) were stimulated with bleomycin to induce apoptosis. Administration of BIP-V5 improved the survival rate and degree of bleomycin-induced lung injury by suppressing Bax activation in mice. BIP-V5 treatment decreased bleomycin-induced apoptosis of alveolar epithelial cell lines (A549 cells and LA-4 cells) by suppressing Bax activation. These results indicate that administration of BIP-V5 may constitute a novel therapeutic strategy against lung injury. Summary: The inhibiting peptide for Bax, a pro-apoptotic member of the Bcl-2 family of proteins, ameliorates bleomycin-induced lung injury in mice via apoptosis suppression in epithelial cells.

Recurrent idiopathic pulmonary hemosiderosis after long-term remission presented with Sjogren's syndrome: Idiopathic no more?

We report a case of recurrent idiopathic pulmonary hemosiderosis after a long-term remission presented with Sjögrens syndrome. The patient was diagnosed with IPH due to repeated pneumonia and blood sputum in his childhood. He was admitted to our hospital due to exertional dyspnea and dry cough with bilateral ground-glass opacity in chest computed tomography at the age of 32. Video-assisted thoracoscopic surgery was performed and the specimens showed nonspecific interstitial pneumonia pattern with diffuse, chronic alveolar hemorrhage, suggesting recurrence of IPH. He was also diagnosed with Sjögrens syndrome. Further immunological studies will reveal the pathogenesis of IPH.

Interstitial pneumonia caused by dabigatran

We describe the case of a 73-year-old man who experienced dry cough and exertional dyspnea after dabigatran administration. Chest radiographs revealed the development of bilateral consolidative and ground glass opacity, and transbronchial lung biopsy showed organized materials in the alveolar spaces with moderate inflammatory infiltrate and focal fibrosis. Lung opacity gradually disappeared after discontinuing dabigatran. To date, there has been only one report regarding dabigatran-induced lung injury, except for alveolar hemorrhage and eosinophilic pneumonia. Therefore, we should consider that any drug can cause various types of lung injuries.

An autopsy case of bird-related chronic hypersensitivity pneumonitis presenting with repeated acute exacerbation

A 68-year-old woman was admitted to our hospital with a dry cough in 2010. Chest computed tomography showed the appearance of a nonspecific interstitial pneumonia (NSIP) pattern. Video-assisted thoracoscopic surgery (VATS) was performed, and the specimens prominently showed a usual interstitial pneumonia (UIP) pattern. She was diagnosed with bird-related chronic hypersensitivity pneumonitis (BRCHP) on the basis of the detection of antibodies to pigeon dropping extract in her serum and a history of using feather-filled duvets and indirect exposure to birds in her living environment. Even though she was treated with corticosteroids and immunosuppressants and recommended to avoid bird-related antigens, she had a progressive course with repeated acute exacerbation episodes and died of respiratory failure. The autopsy findings showed diffuse alveolar damage superimposed on UIP. Clinicians should be aware that BRCHP patients especially with histopathologically UIP pattern may experience acute exacerbation.

Detection of identical T cell clones in peritumoral pleural effusion and pneumonitis lesions in a cancer patient during immune-checkpoint blockade

Although immune-related adverse events (irAEs) of treatment with immune-checkpoint inhibitors may be due to cellular immunity mediated by T lymphocytes, their pathogenesis has remained unknown. Here we collected bronchoalveolar lavage fluid (BALF) from a cancer patient with nivolumab-induced pneumonitis and isolated mononuclear cells for next-generation sequencing of the complementarity-determining region of the T cell receptor (TCR) β chain. Mononuclear cells in peritumoral pleural effusion isolated from the patient were similarly analyzed, and the results obtained for the two specimens were compared. A substantial number of TCRβ clones in BALF were also identified among lymphocytes in the peritumoral pleural effusion. Such a correlation was not apparent between TCRβ clones in BALF and those in peripheral blood. Moreover, many tumor-associated clones with a read frequency of ≥0.10% were also present in BALF. Our data suggest that irAEs might be induced by drug-activated lymphocytes originating from tumor tissue. Deep sequencing will thus be indispensable for investigations of the immune-based pathogenesis of, and the development of optimal treatments for, irAEs.

Treatment with a programmed cell death-1-specific antibody has little effect on afatinib- and naphthalene-induced acute pneumonitis in mice

Although several antibodies developed to target programmed cell death-1 (PD-1) and its ligand (PD-L1) have demonstrated great promise for the treatment of non-small cell lung cancer (NSCLC), and other malignancies, these therapeutic antibodies can cause pneumonitis. Furthermore, epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI)-induced pneumonitis was reported after treatment with anti PD-1 antibodies. We previously demonstrated that mice with naphthalene-induced airway epithelial injury developed severe gefitinib-induced pneumonitis through a neutrophil-dependent mechanism. The present study aimed to investigate whether treatment with afatinib, an EGFR-TKI that effectively targets EGFR mutation-positive NSCLC, and anti PD-1 antibodies induces pneumonitis in mice. C57BL/6J mice were treated intraperitoneally with naphthalene (200xa0mg/kg) on day 0. Afatinib (20xa0mg/kg) was administered orally on daysxa0-1 to 13. An anti-PD-1 antibody (0.2 mg/mice) was also administered intraperitoneally every 3 days from day 1 until day 13. The bronchoalveolar lavage fluid (BALF) and lung tissues were sampled on day 14. As observed previously with gefitinib, afatinib significantly increased the severity of histopathologic findings and the level of protein in BALF on day 14, compared to treatment with naphthalene alone. A combined anti-PD-1 antibody and afatinib treatment after naphthalene administration had yielded the same histopathological grade of lung inflammation as did afatinib treatment alone. Our results suggest that anti-PD-1 antibody treatment has little effect on afatinib-induced lung injury.