SCIENTIFIC REPORTS | ARTICLE OPEN
Real-time single-cell imaging of protein secretion
Yoshitaka Shirasaki, Mai Yamagishi, Nobutake Suzuki, Kazushi Izawa, Asahi Nakahara, Jun Mizuno, Shuichi Shoji, Toshio Heike, Yoshie Harada, Ryuta Nishikomori & Osamu Ohara
AffiliationsContributionsCorresponding author
Scientific Reports 4, Article number: 4736 doi:10.1038/srep04736
Received 03 October 2013 Accepted 02 April 2014 Published 22 April 2014
Protein secretion, a key intercellular event for transducing cellular signals, is thought to be strictly regulated. However, secretion dynamics at the single-cell level have not yet been clarified because intercellular heterogeneity results in an averaging response from the bulk cell population. To address this issue, we developed a novel assay platform for real-time imaging of protein secretion at single-cell resolution by a sandwich immunoassay monitored by total internal reflection microscopy in sub-nanolitre-sized microwell arrays. Real-time secretion imaging on the platform at 1-min time intervals allowed successful detection of the heterogeneous onset time of nonclassical IL-1ß secretion from monocytes after external stimulation. The platform also helped in elucidating the chronological relationship between loss of membrane integrity and IL-1ß secretion. The study results indicate that this unique monitoring platform will serve as a new and powerful tool for analysing protein secretion dynamics with simultaneous monitoring of intracellular events by live-cell imaging.