title: Time-lapse imaging of morphological changes in a single neuron during the early stages of apoptosis using scanning ion conductance microscopy.
abstract: Apoptosis plays an important role in many physiologic and pathologic conditions. The biochemical and morphological characteristics of apoptosis including cellular volume decrease, cell membrane blebbing, and phosphatidylserine translocation from the inner to the outer leaflet of the cell membrane are considered important events for phagocyte detection. Despite its importance, the relationship between the biological and morphological changes in a living cell has remained controversial. Scanning ion conductance microscopy is a suitable technique for investigating a series of these changes, because it allows us to observe the morphology of living cells without any mechanical interactions between the probe and the sample surface with a high resolution. Here, we investigated the biochemical and morphological changes in single neurons during the early stages of apoptosis, including apoptotic volume decrease, membrane blebbing and phosphatidylserine translocation, by using scanning ion conductance microscopy. Time-course imaging of apoptotic neurons showed there was a reduction in apoptotic volume after exposure to staurosporine and subsequent membrane bleb formation, which has a similar onset time to phosphatidylserine translocation. Our results show that a reduction in cellular volume is one of the earliest morphological changes in apoptosis, and membrane blebbing and phosphatidylserine translocation occur as subsequent biological and morphological changes. This is the first report to describe this series of morphological and biochemical changes ranging from an apoptotic volume decrease to membrane blebbing and PS translocation by scanning ion conductance microscopy (SICM). This new and direct imaging technique will provide new insight into the relationship between biochemical events inside a cell and cellular morphological changes.
authors.affiliation: NTT Basic Research Laboratories NTT Corporation, 3-1 Morinosato Wakamiya, Atsugi, Kanagawa 243-0198, Japan. Electronic address: tanaka.aya@lab.ntt.co.jp.
authors.forename: Aya
authors.initials: A
authors.lastname: Tanaka
authors.affiliation: Graduate School of Information Science and Technology, Hokkaido University, Kita-ku N14 W9, Sapporo 060-0814, Japan.
authors.forename: Ryosuke
authors.initials: R
authors.lastname: Tanaka
authors.affiliation: NTT Basic Research Laboratories NTT Corporation, 3-1 Morinosato Wakamiya, Atsugi, Kanagawa 243-0198, Japan.
authors.forename: Nahoko
authors.initials: N
authors.lastname: Kasai
authors.affiliation: NTT Basic Research Laboratories NTT Corporation, 3-1 Morinosato Wakamiya, Atsugi, Kanagawa 243-0198, Japan.
authors.forename: Shingo
authors.initials: S
authors.lastname: Tsukada
authors.affiliation: Graduate School of Information Science and Technology, Hokkaido University, Kita-ku N14 W9, Sapporo 060-0814, Japan.
authors.forename: Takaharu
authors.initials: T
authors.lastname: Okajima
authors.affiliation: NTT Basic Research Laboratories NTT Corporation, 3-1 Morinosato Wakamiya, Atsugi, Kanagawa 243-0198, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Sumitomo
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000502:physiology; D002478:Cells, Cultured; D008853:Microscopy; D009474:Neurons / Q000166:cytology*; D010718:Phosphatidylserines / Q000378:metabolism; D051381:Rats; D059008:Time-Lapse Imaging / Q000379:methods*
chemical_list: D010718:Phosphatidylserines
keywords: Apoptosis; Apoptotic volume decrease (AVD); Membrane blebbing; Phosphatidylserine translocation (PS translocation); Scanning ion conductance microscopy (SICM); Time-lapse imaging