Kouji Hayashi

Kyoto University, Kyoto, Kyoto-fu, Japan

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Publications (3)13.02 Total impact

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    ABSTRACT: We previously developed an in vivo tissue suction-mediated transfection method (denoted as the tissue suction method) for naked nucleic acids, such as plasmid DNA (pDNA) and small interfering RNA (siRNA), in mice. However, it remains unclear whether the suction pressure conditions affect the results of this method. Therefore, in the present study, we assembled a computer system to control the suction pressure and investigate the effects of the suction pressure conditions on the efficiency of the liver suction transfection of naked pDNA that encodes luciferase in mice. Using the developed system, we examined the effects of the minimum magnitude of the suction pressure, suction pressure waveform, and suction times of the luciferase expression level in mice livers. We determined that the liver suction method at 5 kPa was not only effective but also caused the lowest hepatic toxicity in mice. Additionally, the results indicated that the suction pressure waveform affects the luciferase expression levels, and a single period of suction on the targeted portion of the liver is sufficient for transfection. Thus, the developed system is useful for performing the tissue suction method with high accuracy and safety.
    Biological & Pharmaceutical Bulletin 01/2014; 37(4):569-75. · 1.85 Impact Factor
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    ABSTRACT: We have developed an in vivo transfection method for naked plasmid DNA (pDNA) and siRNA in mice by using a tissue suction device. The target tissue was suctioned by a device made of polydimethylsiloxane (PDMS) following the intravenous injection of naked pDNA or siRNA. Transfection of pDNA encoding luciferase was achieved by the suction of the kidney, liver, spleen, and heart, but not the duodenum, skeletal muscle, or stomach. Luciferase expression was specifically observed at the suctioned region of the tissue, and the highest luciferase expression was detected at the surface of the tissue (0.12±0.03 ng/mg protein in mice liver). Luciferase expression levels in the whole liver increased linearly with an increase in the number of times the liver was suctioned. Transfection of siRNA targeting glyceraldehyde 3-phosphate dehydrogenase (GAPDH) gene significantly suppressed the expression of GAPDH mRNA in the liver. Histological analysis shows that severe damage was not observed in the suctioned livers. Since the suction device can be mounted onto the head of the endoscope, this method is a minimally invasive. These results indicate that the in vivo transfection method developed in this study will be a viable approach for biological research and therapies using nucleic acids.
    PLoS ONE 07/2012; 7(7):e41319. · 3.53 Impact Factor
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    ABSTRACT: In vivo transfection is an important technique used in biological research and drug therapy development. Previously, we developed a renal pressure-mediated transfection method performed by pressing a kidney after an intravenous injection of naked nucleic acids. Although this is a useful method because of its safety and wide range of applications, an innovative approach for performing this method without repeatedly cutting open the abdomen is required. In this study, we developed an implantable microsystem fabricated by Micro-Electro-Mechanical Systems (MEMS) technologies for renal pressure-mediated transfection. The system consists of a polydimethylsiloxane pneumatic balloon actuator (PBA) used as an actuator to press the target kidney. The PBA of the implanted microsystem can be actuated without opening the abdomen by applying air pressure from outside the body to the pressure-supplying port via a needle. We successfully performed renal pressure-mediated transfection using the newly developed system when the implanted system was activated at 60kPa for 10s. This is the first report of an implantable MEMS-based microsystem that demonstrates in vivo transfection to a kidney using naked plasmid DNA.
    Journal of Controlled Release 12/2011; 159(1):85-91. · 7.63 Impact Factor