PTD-FGF2 Attenuates Elastase Induced Emphysema in Mice and Alveolar Epithelial Cell Injury.

Aberrant communication in alveolar epithelium is a major feature of inflammatory response for the airway remodeling leading to chronic obstructive pulmonary disease (COPD). In this study, we investigated the effect of protein transduction domains (PTD) conjugated Basic Fibroblast Growth Factor (FGF2) (PTD-FGF2) in response to cigarette smoke extract (CSE) in MLE-12 cells and porcine pancreatic elastase (PPE)-induced emphysematous mice. When PPE-induced mice were intraperitoneally treated with 0.1-0.5 mg/kg PTD-FGF2 or FGF2, the linear intercept, infiltration of inflammatory cells into alveoli and pro-inflammatory cytokines were significantly decreased. In western blot analysis, phosphorylated protein levels of c-Jun N-terminal Kinase 1/2 (JNK1/2), extracellular signal-regulated kinase (ERK1/2) and p38 mitogen-activated protein kinases (MAPK) were decreased in PPE-induced mice treated PTD-FGF2. In MLE-12 cells, PTD-FGF2 treatment decreased reactive oxygen species (ROS) production and further decreased Interleukin-6 (IL-6) and IL-1b cytokines in response to CSE. In addition, phosphorylated protein levels of ERK1/2, JNK1/2 and p38 MAPK were reduced. We next determined microRNA expression in the isolated exosomes of MLE-12 cells. In reverse transcription-polymerase chain reaction (RT-PCR) analysis, level of let-7c miRNA was significantly increased while levels of miR-9 and miR-155 were decreased in response to CSE. These data suggest that PTD-FGF2 treatment plays a protective role in regulation of let-7c, miR-9 and miR-155 miRNA expressions and MAPK signaling pathways in CSE-induced MLE-12 cells and PPE-induced emphysematous mice.

WKYMVm ameliorates acute lung injury via neutrophil antimicrobial peptide derived STAT1/IRF1 pathway.

Formyl peptide receptors (FPRs) are mainly expressed on leucocytes and sense microbe-associated molecular pattern (MAMP) molecules, thereby regulating leukocyte chemotaxis and activation. The formyl peptide receptor 2 (FPR2) selective agonist WKYMVm (Trp-Lys-Met-Val-D-Met) has shown potent pro-angiogenic, anti-inflammatory, and anti-apoptotic properties. In this study, we investigated whether WKYMVm exhibits bactericidal activity during neutrophil accumulation in acute lung injury (ALI) in mice and determined its cellular signaling pathways in HL-60 neutrophil-like cells. A daily intraperitoneal treatment of ALI mice with WKYMVm (2.5- and 5 mg/kg/d) daily over four days decreased the levels of proinflammatory cytokines TNF-α, IL-6, and IL-1ß, while it increased the MPO and NO release by differentiated HL-60 neutrophil-like cells. The IRF1 level and STAT1 phosphorylation at S727 were increased in the lungs of mice with ALI treated with WKYMVm. Lung histology induced by ALI was unaffected by treatment with WKYMVm. In vitro, WKYMVm increased MPO, NO, and SOD activity, as well as IRF1 and STAT1 phosphorylation at Ser727. Taken together, our data suggest therapeutic potential of WKYMVm, via FPR2-dependent regulation of STAT1/IRF1, in ALI.