The Effect of CC16 on Macrophage Polarization

Abstract

Club Cell Secretory Protein (CC16) is a protein that is secreted in the lungs and exhibits protective effects against the development of obstructive lung diseases, altered pulmonary function, airway remodeling, and helps lower pathogenic load in the lungs [3]. Deficiencies in CC16 have been linked to worsened symptoms in asthma [13], rapid decrease of lung function in COPD-like disease in mice [14] and has been linked to increasing airway remodeling in mice [12]. rCC16 has been demonstrated to regulate the expression of pro-inflammatory cytokines via NF-kB. Resident macrophages are known to participate in a variety of these processes, but whether CC16 exerts protective effects in the lung via macrophage-dependent mechanisms remains unknown and was the topic of study in this thesis. Experiments were conducted with RAW 264.7 and immortalized bone marrow derived macrophages (IBMDM) cells to shed light on the effects of CC16 on macrophage polarization. Stimulated RAW 264.7 cells were used to measure M2 polarization in the presence of M2 stimuli with and without rCC16. In these studies, rCC16 had minimal impact on limiting M2 polarization of RAW 264.7 cells at the dose and time point tested. Both RAW 264.7 and IBMDM cells were used to measure gene expression associated with M2 macrophage polarization, including expression of genes for IL-10, IL-13, Arg1, and PPAR-G. Major findings were that in RAW 264.7 cells, IL-10 was significantly upregulated by rCC16 alone and PPAR-G was significantly downregulated by rCC16 in the presence of IL-4+IL-13. In IBMDM cells, rCC16 has less impact on M2 gene expression resulting from IL-4 stimulation, however, rCC16 alone and in the presence of IL-4, also increased IL-10 gene expression.