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リエゾンラボ研究会
発表内容

Title:
From cartoon to real biology: intravital multiphoton imaging of cellular dynamics in bone resorption, inflammation and cancers.

Masaru Ishii
Professor
Laboratory of Cellular Dynamics, Immunology Frontier Research Center , Osaka University , Japan

Abstract:
During the last decade, multi-photon microscopy has launched a new era in the field of biological imaging. The near-infrared excitation laser for multi-photon microscopy can penetrate thicker specimens, enabling the visualization of living cell behaviors deep within tissues and organs without thin sectioning. The minimized photo-bleaching and toxicity contributes to the visualization of live and intact specimens for extended observation periods. By using this advanced imaging technique we have established a new system for visualizing in situ behavior of a diversity of living cells within intact tissues and organs.
Bone has been a mysterious organ where various kinds of hematopoietic cells are resident and undergo maturation or differentiation into specific lineages, processes that occur in specialized locations called ‘niches’, and proper localization of precursor cells to such niches is the first critical step for effective subsequent developmental processes. However, by means of conventional methodology such as histological analyses with fixed and decalcified bone tissues, the information regarding cellular movements was completely missing. To analyze their movements in vivo, we must definitely see them in live bone tissues. By means of ‘intravital’ multiphoton microscopy, we succeeded in visualizing the various dynamic phenomena in bone marrow cavity. Especially we have focused on the behavior of osteoclast, a cell type contributing bone remodeling, and revealed a novel mechanism controlling migration and localization of osteoclasts in situ.
In this presentation, I will present the latest data on this new concept in the field of bone and inflammatory biology, as well as show our recent trials for visualizing and analysing the cellular dynamics in various kinds of biological systems such as immune reaction and cancer cell invasion. I would also like to discuss the future application of this novel methodology in immunology and more.

References:
1. Ishii M, et al. Chemorepulsion by blood S1P regulates osteoclast precursor mobilization and bone remodeling in vivo. J. Exp. Med. 207. 2793-2798, 2010.

2. Ishii M, et al. Sphingosine-1-phosphate mobilizes osteoclast precursors and regulates bone homeostasis. Nature. 458. 524-528, 2009.