Modulation of Human Neutrophil Peptides on P. aeruginosa Killing, Epithelial Cell Inflammation and Mesenchymal Stromal Cell Secretome Profiles

Abstract

Qingqing Dai,1,* Yasumasa Morita,2,* Yongbo Huang,3 Patricia C Liaw,4 Jianfeng Wu,5 Julie Khang,6 Diana Islam,6 Kaijiang Yu,7 Yimin Li,3 Haibo Zhang3,8–10 1Department of Critical Care Medicine, The 2nd Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang, People’s Republic of China; 2Department of Emergency and Critical Care Medicine, Chiba Aoba Municipal Hospital, Chiba, Japan; 3The State Key Laboratory of Respiratory Disease, and The 1st Affiliated Hospital of Guangzhou Medical University, Guangzhou, People’s Republic of China; 4Department of Medicine, McMaster University, Hamilton, Canada; 5Department of Critical Care Medicine, The 1st Affiliated Hospital of Sun Yat-Sen University, Guangzhou, People’s Republic of China; 6Keenan Research Center for Biomedical Science of Unity Health Toronto, Toronto, Canada; 7Department of Critical Care Medicine, The 1st Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang, People’s Republic of China; 8Interdepartmental Division of Critical Care Medicine, University of Toronto, Ontario, Canada; 9Departments of Anesthesia, University of Toronto, Ontario, Canada; 10Physiology, University of Toronto, Ontario, Canada*These authors contributed equally to this workCorrespondence: Kaijiang Yu 23 Youzheng Street, Harbin, Heilongjiang 150001, People’s Republic of ChinaTel/Fax [phone]Email [email protected] Li 151 Yanjiang Road West, Guangzhou, Guangdong 510120, People’s Republic of ChinaTel/Fax [phone]Email [email protected]: Neutrophil infiltration and release of the abundant human neutrophil peptides (HNP) are a common clinical feature in critically ill patients. We tested a hypothesis that different cell types respond to HNP differently in lung microenvironment that may influence the host responses.Methods: Plasma concentrations of HNP were measured in healthy volunteers and patients with sepsis. Cells including the bacteria P. aeruginosa, human lung epithelial cells and mesenchymal stromal cells (MSCs) were exposed to various concentrations of HNP. Bacterial killing, epithelial cell inflammation, MSC adhesion and behaviours were examined after HNP stimulation.Results: Incubation of P. aeruginosa or stimulation of human lung epithelial cells with HNP resulted in bacterial killing or IL-8 production at a dose of 50 μg/mL, while MSC adhesion and alternations of secretome profiles took place after HNP stimulation at a dose of 10 μg/mL. The secretome profile changes were characterized by increased release of the IL-6 family members such as C-reactive protein (CRP), leukemia inhibitory factor (LIF) and interleukin (IL-11), and first apoptosis signal (FAS) and platelet-derived growth factor-AA as compared to a vehicle control group.Conclusion: Stimulation of MSCs with HNP resulted in changes of secretome profiles at 5-fold lower concentration than that required for bacterial killing and lung epithelial inflammation. This undisclosed risk factor of HNP in lung environment should be taken into consideration when MSCs are applied as cell therapy in inflammatory lung diseases.Keywords: defensins, sepsis, lung injury, cytokines

Keywords

• defensins
• sepsis
• lung injury
• cytokines