Chemical Principles in Tissue Clearing and Staining Protocols for Whole-Body Cell Profiling.
Mammalian bodies have more than a billion cells per cubic centimeter, which makes whole-body cell (WBC) profiling of an organism one of the ultimate challenges in biology and medicine. Recent advances in tissue-clearing technology have enabled rapid and comprehensive cellular analyses in whole organs and in the whole body by a combination of state-of-the-art technologies of optical imaging and image informatics. In this review, we focus mainly on the chemical principles in currently available techniques for tissue clearing and staining to facilitate our understanding of their underlying mechanisms. Tissue clearing is usually conducted by the following steps: (a) fixation, (b) permeabilization, (c) decolorizing, and (d) refractive index (RI) matching. To phenotype individual cells after tissue clearing, it is important to visualize genetically encoded fluorescent reporters and/or to stain tissues with fluorescent dyes, fluorescent labeled antibodies, or nucleic acid probes. Although some technical challenges remain, the chemical principles in tissue clearing and staining for WBC profiling will enable various applications, such as identifying cellular circuits across multiple organs and measuring their dynamics in stochastic and proliferative cellular processes, for example, autoimmune and malignant neoplastic diseases.
Department of Systems Pharmacology, The University of Tokyo, Tokyo 113-0033, Japan.
Kazuki
K
Tainaka
Department of Anatomy and Embryology, Faculty of Medicine, University of Tsukuba, Ibaraki 305-8575, Japan.|PhD Program in Human Biology, School of Integrative and Global Majors, University of Tsukuba, Ibaraki 305-8575, Japan.
Akihiro
A
Kuno
Department of Systems Pharmacology, The University of Tokyo, Tokyo 113-0033, Japan.
Shimpei I
SI
Kubota
Department of Systems Pharmacology, The University of Tokyo, Tokyo 113-0033, Japan.
Tatzya
T
Murakami
Department of Systems Pharmacology, The University of Tokyo, Tokyo 113-0033, Japan.|Laboratory for Synthetic Biology, RIKEN Quantitative Biology Center, Suita, Osaka 565-0871, Japan; email: uedah-tky@umin.ac.jp.
Hiroki R
HR
Ueda
D000818:Animals; D002477:Cells / Q000378:metabolism*; D005453:Fluorescence; D006801:Humans; D010539:Permeability; D012031:Refractometry; D013194:Staining and Labeling; D016707:Tissue Fixation / Q000379:methods*
RI matching; chemical staining; decolorizing; fixation; permeabilization; tissue clearing