@article {NakaharaPA2449, author = {Yoshio Nakahara and Naozumi Hashimoto and Koji Sakamoto and Akira Ando and Masahide Inoue and Atsushi Suzuki and Atsushi Enomoto and Yoshinori Hasegawa}, title = {The new-defined mesenchymal stromal/stem cell marker has a protective role in the development of acute lung injury}, volume = {54}, number = {suppl 63}, elocation-id = {PA2449}, year = {2019}, doi = {10.1183/13993003.congress-2019.PA2449}, publisher = {European Respiratory Society}, abstract = {Background: Acute lung injury is characterized by infiltration of mixed inflammatory cells and diffuse destruction of the alveolar{\textendash}capillary barrier. Although some stem cells populations are reported to regulate lung homeostasis in lung tissues, vascular adventitial fibroblasts involve mesenchymal stem/progenitor cells. In a recent study, a newly defined MSCs marker A was identified as a regulator of their undifferentiated state in fibroblasts. However, the roles of the marker A in the development of acute lung injury have not been investigated.Objectives: We examined the expression of the marker A in the lung and its involvement in acute lung injury.Methods and Results: In a model of bleomycin (BLM)-induced acute lung injury, the expression of the marker A in whole lung elevated on day 7 and peaked on day 14 in BLM group. Histological analysis revealed that whereas the marker A-positive cell located slightly at peribronchiolar and perivascular lesion in control group, they located robustly at fibrotic lesion in BLM group. The gene A knock out (KO) mice exhibited a drastic loss of body weight and a shorter survival after BLM administration than did WT mice. Histological analysis showed abnormal infiltration of inflammatory cells in the BLM-treated gene A KO mice. Analysis of bronchoalveolar lavage fluid (BALF) revealed an increase in the numbers of neutrophils and total protein concentration in the BLM-treated gene A KO mice.Conclusion: These data suggested that the newly defined MSCs marker A may have a protective role in the development of acute lung injury.FootnotesCite this article as: European Respiratory Journal 2019; 54: Suppl. 63, PA2449.This is an ERS International Congress abstract. No full-text version is available. Further material to accompany this abstract may be available at www.ers-education.org (ERS member access only).}, issn = {0903-1936}, URL = {https://erj.ersjournals.com/content/54/suppl_63/PA2449}, eprint = {https://erj.ersjournals.com/content}, journal = {European Respiratory Journal} }