Identification of in vitro differential cell secretions due to cigarette smoke condensate exposure using nanoflow capillary liquid chromatography and high-resolution mass spectrometry.

Secreted proteins, the secretome, can be isolated from biological fluids (e.g., blood) and are often responsible for the regulation of biological processes such as cell signaling, growth, and apoptosis. The identification of secreted proteins can lead to an understanding of disease mechanisms and they can serve as early candidate biomarkers of disease and exposure. However, it is time-consuming and costly to conduct in vivo interrogations of the human secretome. The purpose of this article is to provide a detailed description of a rapid in vitro technique for the analysis of differential protein secretion due to exposure to smoking-machine-generated cigarette smoke (CS) condensate (total particulate matter, TPM). Endothelial cells were exposed to CS-TPM, the supernatant was collected, and the secretome was elucidated by nano liquid chromatography coupled with high-resolution mass spectrometry. A total of 1,677 unique peptides were identified in the cell culture supernatants. Several proteins were differentially expressed following CS-TPM exposure that relate to several biological processes, such as metabolism, development, communication, response to stimulus, and response to stress.