Saiko Ogata-Suetsugu

EGFR Tyrosine Kinase Inhibition Worsens Acute Lung Injury in Mice with Repairing Airway Epithelium

RATIONALE Epidermal growth factor receptor (EGFR) and its ligands play important roles in the regeneration of damaged epithelium and proliferation of various epithelial tumors. Although the EGFR-tyrosine kinase inhibitor gefitinib is effective against advanced non-small cell lung cancer with EGFR mutations, some patients treated with this agent develop severe acute interstitial pneumonia. Characteristics of patients who develop interstitial pneumonia include older age, smoking history, and preexisting interstitial pneumonia suggesting a connection between airway injury and alveolar dysfunction. OBJECTIVES The purpose of this study was to investigate the effects of gefitinib on airway repair after injury. METHODS C57BL/6J mice received intraperitoneally naphthalene at Day 0. Gefitinib (20, 90, or 200 mg/kg) was given daily at Days--1 to 13 after naphthalene administration. Bronchoalveolar lavage fluid and lung tissue were obtained at Days 7 and 14. Terminal bronchial epithelial cells from Days 7 and 14 were retrieved with laser capture microdissection, and gene expression analyzed using microarray. MEASUREMENTS AND MAIN RESULTS Gefitinib treatment after naphthalene prolonged neutrophil sequestration and worsened acute lung injury. We found 17 genes with more than a threefold increase in bronchiolar epithelial cells from mice treated with 200 mg/kg of gefitinib after naphthalene at Day 14 compared with those treated with naphthalene alone. Up-regulated genes included S100A8, S100A6, and StefinA3. These genes are known to participate in neutrophil sequestration, acute inflammation, and airway remodeling. CONCLUSIONS EGFR inhibition in repairing airway epithelial cells modulated significant expression of genes involved in the airway microenvironment, prolonged inflammation, and potentiated acute lung injury.

Association between genetic polymorphisms involved in the hypoxia-inducible factor pathway and lung cancer risk: A case-control study in Japan

Hypoxia‐inducible factor (HIF) contributes to the adaptation of tumor cells to hypoxic conditions, so genetic polymorphisms involved in this pathway may affect cellular response to hypoxia and be associated with cancer risk. Thus, we examined the association between the lung cancer risk and genetic polymorphisms involved in the HIF pathway.

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.