Biology subjects

Kakizuka, T.

Publications and source records attributed to Kakizuka, T..

4 recordsLinked to original sources

bioRxiv2024

The crucial role of intercellular calcium wave propagation triggered by influenza A virus in promoting infection

Influenza A viruses (IAVs) initially infect a few host cells, and the infection subsequently spreads to neighboring cells. However, the molecular mechanisms underlying this expansion remain unclear. Here, we show that IAV infection upregulates the frequency of intercellular calcium wave propagations (iCWPs) that mediate the spread of IAVs. ADP released from initially infected cells mediated iCWPs via the P2Y1 receptor. The generation of iCWPs and spread of viral infection were inhibited by a P2Y1 antagonist. Enhanced endocytosis in the surrounding cells that received ADP signaling upregulated viral entry. Expression of IAV matrix protein 2 (M2) in initially infected cells triggered iCWPs through ADP diffusion, thereby increasing infection, whereas an ion permeability-deficient mutation of M2 or inhibition of its ion channel activity suppressed iCWPs. Therefore, intercellular calcium signaling is essential for early expansion and potential establishment of IAV infection, which offers a promising target for IAV prophylaxis.

cell biology↗

bioRxiv2023

Volumetric trans-scale imaging of massive quantity of heterogeneous cell populations in centimeter-wide tissue and embryo

We established a volumetric trans-scale imaging system with an ultra-large field-of-view (FOV) that enables simultaneous observation of millions of cellular dynamics in centimeter-wide three-dimensional (3D) tissues and embryos. Using a custom-made giant lens system with a magnification of 2x and a numerical aperture (NA) of 0.25, and a CMOS camera with more than 100 megapixels, we built a trans-scale scope AMATERAS-2, and realized fluorescence imaging with a transverse spatial resolution of approximately 1.1 {micro}m across an FOV of approximately 1.5 x 1.0 cm2. The 3D resolving capability was realized through a combination of optical and computational sectioning techniques tailored for our low-power imaging system. We applied the imaging technique to 1.2 cm-wide section of mouse brain, and successfully observed various regions of the brain with sub-cellular resolution in a single FOV. We also performed time-lapse imaging of a 1-cm-wide vascular network during quail embryo development for over 24 hours, visualizing the movement of over 4.0 x 105 vascular endothelial cells and quantitatively analyzing their dynamics. Our results demonstrate the potential of this technique in accelerating production of comprehensive reference maps of all cells in organisms and tissues, which contributes to understanding developmental processes, brain functions, and pathogenesis of disease, as well as high-throughput quality check of tissues used for transplantation medicine.

developmental biology↗

bioRxiv2020

Trans-scale-scope to find rare cellular activity in sub-million cells

In many phenomena of biological systems, not a majority, but a minority of cells act on the entire multicellular system causing drastic changes in the system properties. To understand the mechanisms underlying such phenomena, it is essential to observe the spatiotemporal dynamics of a huge population of cells at sub-cellular resolution, which is difficult with conventional tools such as microscopy and flow cytometry. Here, we describe an imaging system named AMATERAS that enables optical imaging with an over-one-centimeter field-of-view and a-few-micrometer spatial resolution. This trans-scale-scope has a simple configuration, composed of a low-power lens for machine vision and a hundred-megapixel image sensor. We demonstrated its high cell-throughput, capable of simultaneously observing more than one million cells. We applied it to dynamic imaging of calcium ions in HeLa cells and cyclic-adenosine-monophosphate in Dictyostelium discoideum, and successfully detected less than 0.01% of rare cells and observed multicellular events induced by these cells.

cell biology↗

bioRxiv2020

Cellular logics bringing the symmetry breaking in spiral nucleation revealed by trans-scale imaging

SummaryThe spiral wave is a commonly observed spatio-temporal order in diverse signal relaying systems. Although properties of generated spirals have been well studied, the mechanisms for their spontaneous generation in living systems remain elusive. By the newly developed imaging system for trans-scale observation of the intercellular communication among ∼130,000 cells of social amoeba, we investigated the onset dynamics of cAMP signaling and identified mechanisms for the self-organization of the spiral wave at three distinct scalings: At the population-level, the structured heterogeneity of excitability fragments traveling waves at its high/low boundary, that becomes the generic source of the spiral wave. At the cell-level, both the pacemaking leaders and pulse-amplifying followers regulate the heterogeneous growth of the excitability. At the intermediate-scale, the essence of the spontaneous wave fragmentation is the asymmetric positioning of the pacemakers in the high-excitability territories, whose critical controls are operated by a small number of cells, pulse counts, and pulse amounts.Competing Interest StatementThe authors have declared no competing interest.View Full Text

systems biology↗