Metabolic trajectory of cellular differentiation in small intestine by Phasor Fluorescence Lifetime Microscopy of NADH

• DOI: 10.1038/srep00568
• Publication Date: 2012-08-10T09:11:46Z
• Authors: Chiara Stringari; Robert A. Edwards; Kira T. Pate; Marian L. Waterman; Peter J. Donovan; Enrico Gratton
• Keywords: catenin; autofluorescence; Article; stem-cells; Mice; 03 medical and health sciences; expression; Intestine, Small; Animals; signaling components; live tissue; Intestinal Mucosa; Cell Proliferation; 0303 health sciences; Stem Cells; Cell Differentiation; Epithelial Cells; NAD; states; Microscopy, Fluorescence; Cell Tracking; cancer cells; vivo; epithelium; Biomarkers

There is a lack of fast and high resolution methods to measure metabolic activity of single cells in their native environment. Here we develop a straightforward, non-invasive and sensitive method to measure metabolic phenotype of single cells in a live tissue. By using NADH as optical biomarker and the phasor approach to Fluorescence Lifetime microscopy (FLIM) we identify cellular metabolic fingerprints related to different rates of oxidative phosphorylation and glycolysis. For the first time we measure a three dimensional metabolic gradient in the small intestine (SI) epithelia that appears tightly associated with epithelial cell proliferation, differentiation and the Wnt gradient. The highest free/bound NADH ratios are measured at the base of the crypt within the highly proliferative stem cells, indicating high levels of glycolysis. For the first time mouse small intestinal stem cells in intact live crypts are identified within the tissue by their metabolic fingerprint.