Yasunori Shintani

Publications (40) View all

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  Available from: Yasunori Shintani

  Article: TLR9 mediates cellular protection by modulating energy metabolism in cardiomyocytes and neurons.

  Yasunori Shintani, Amar Kapoor, Masahiro Kaneko, Ryszard T Smolenski, Fulvio D'Acquisto, Steven R Coppen, Narumi Harada-Shoji, Hack Jae Lee, Christoph Thiemermann, Seiji Takashima, Kenta Yashiro, Ken Suzuki
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  ABSTRACT: Toll-like receptors (TLRs) are the central players in innate immunity. In particular, TLR9 initiates inflammatory response by recognizing DNA, imported by infection or released from tissue damage. Inflammation is, however, harmful to terminally differentiated organs, such as the heart and brain, with poor regenerative capacity, yet the role of TLR9 in such nonimmune cells, including cardiomyocytes and neurons, is undefined. Here we uncover an unexpected role of TLR9 in energy metabolism and cellular protection in cardiomyocytes and neurons. TLR9 stimulation reduced energy substrates and increased the AMP/ATP ratio, subsequently activating AMP-activated kinase (AMPK), leading to increased stress tolerance against hypoxia in cardiomyocytes without inducing the canonical inflammatory response. Analysis of the expression profiles between cardiomyocytes and macrophages identified that unc93 homolog B1 (C. elegans) was a pivotal switch for the distinct TLR9 responses by regulating subcellular localization of TLR9. Furthermore, this alternative TLR9 signaling was also found to operate in differentiated neuronal cells. These data propose an intriguing model that the same ligand-receptor can concomitantly increase the stress tolerance in cardiomyocytes and neurons, whereas immune cells induce inflammation upon tissue injury.
  Proceedings of the National Academy of Sciences 03/2013; · 9.68 Impact Factor
• Article: The Use of Scaffold-free Cell Sheet Technique to Refine Mesenchymal Stromal Cell-based Therapy for Heart Failure.

  Takuya Narita, Yasunori Shintani, Chiho Ikebe, Masahiro Kaneko, Niall G Campbell, Steven R Coppen, Rakesh Uppal, Yoshiki Sawa, Kenta Yashiro, Ken Suzuki
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  ABSTRACT: Transplantation of bone marrow-derived mesenchymal stromal cells (MSCs) is an emerging treatment for heart failure based on their secretion-mediated "paracrine effects". Feasibility of the scaffoldless cell sheet technique to enhance the outcome of cell transplantation has been reported using other cell types, though the mechanism underpinning the enhancement remains uncertain. We here investigated the role of this innovative technique to amplify the effects of MSC transplantation with a focus on the underlying factors. After coronary artery ligation in rats, syngeneic MSCs were grafted by either epicardial placement of MSC sheets generated using temperature-responsive dishes or intramyocardial (IM) injection. Markedly increased initial retention boosted the presence of donor MSCs persistently after MSC sheet placement although the donor survival was not improved. Most of the MSCs grafted by the cell sheet technique remained resided on the epicardial surface, but the epicardium quickly regressed and new vessels sprouted into the sheets, assuring the permeation of paracrine mediators from MSCs into the host myocardium. In fact, there was augmented upregulation of various paracrine effect-related genes and signaling pathways in the early phase after MSC sheet therapy. Correspondingly, more extensive paracrine effects and resultant cardiac function recovery were achieved by MSC sheet therapy. Further development of this approach towards clinical application is encouraged.Molecular Therapy (2013); doi:10.1038/mt.2013.9.
  Molecular Therapy 01/2013; · 6.87 Impact Factor
• Article: The use of cell-sheet technique eliminates arrhythmogenicity of skeletal myoblast-based therapy to the heart with enhanced therapeutic effects.

  Takuya Narita, Yasunori Shintani, Chiho Ikebe, Masahiro Kaneko, Narumi Harada, Nomathamsanqa Tshuma, Kunihiko Takahashi, Niall G Campbell, Steven R Coppen, Kenta Yashiro, Yoshiki Sawa, Ken Suzuki
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  ABSTRACT: BACKGROUND: Clinical application of skeletal myoblast transplantation has been curtailed due to arrhythmogenicity and inconsistent therapeutic benefits observed in previous studies. However, these issues may be solved by the use of a new cell-delivery mode. It is now possible to generate "cell-sheets" using temperature-responsive dishes without artificial scaffolds. This study aimed to validate the safety and efficacy of epicardial placement of myoblast-sheets (myoblast-sheet therapy) in treating heart failure. METHODS AND RESULTS: After coronary artery ligation in rats, the same numbers of syngeneic myoblasts were transplanted by intramyocardial injection or cell-sheet placement. Continuous radio-telemetry monitoring detected increased ventricular arrhythmias, including ventricular tachycardia, after intramyocardial injection compared to the sham-control, while these were abolished in myoblast-sheet therapy. This effect was conjunct with avoidance of islet-like cell-cluster formation that disrupts electrical conduction, and with prevention of increased arrhythmogenic substrates due to exaggerated inflammation. Persistent ectopic donor cells were found in the lung only after intramyocardial injection, strengthening the improved safety of myoblast-sheet therapy. In addition, myoblast-sheet therapy enhanced cardiac function, corresponding to a 9.2-fold increase in donor cell survival, compared to intramyocardial injection. Both methods achieved reduced infarct size, decreased fibrosis, attenuated cardiomyocyte hypertrophy, and increased neovascular formation, in association with myocardial upregulation of a group of relevant molecules. The pattern of these beneficial changes was similar between two methods, but the degree was more substantial after myoblast-sheet therapy. CONCLUSION: The cell-sheet technique enhanced safety and therapeutic efficacy of myoblast-based therapy, compared to the current method, thereby paving the way for clinical application.
  International journal of cardiology 10/2012; · 7.08 Impact Factor
• Article: A simple and novel method for RNA-seq library preparation of single cell cDNA analysis by hyperactive Tn5 transposase.

  Scott Brouilette, Scott Kuersten, Charles Mein, Monika Bozek, Anna Terry, Kerith-Rae Dias, Leena Bhaw-Rosun, Yasunori Shintani, Steven Coppen, Chiho Ikebe, Vinit Sawhney, Niall Campbell, Masahiro Kaneko, Nobuko Tano, Hidekazu Ishida, Ken Suzuki, Kenta Yashiro
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  ABSTRACT: Background: Deep sequencing of single cell-derived cDNAs offers novel insights into oncogenesis and embryogenesis. However, traditional library preparation for RNA-seq analysis requires multiple steps with consequent sample loss and stochastic variation at each step significantly affecting output. Thus, a simpler and better protocol is desirable. The recently developed hyperactive Tn5-mediated library preparation, which brings high quality libraries, is likely one of the solutions. Results and Conclusions: Here, we tested the applicability of hyperactive Tn5-mediated library preparation to deep sequencing of single cell cDNA, optimized the protocol, and compared it with the conventional method based on sonication. This new technique does not require any expensive or special equipment, which secures wider availability. A library was constructed from only 100 ng of cDNA, which enables the saving of precious specimens. Only a few steps of robust enzymatic reaction resulted in saved time, enabling more specimens to be prepared at once, and with a more reproducible size distribution among the different specimens. The obtained RNA-seq results were comparable to the conventional method. Thus, this Tn5-mediated preparation is applicable for anyone who aims to carry out deep sequencing for single cell cDNAs. Developmental Dynamics 241:1584-1590, 2012. © 2012 Wiley Periodicals Inc.
  Developmental Dynamics 08/2012; 241(10):1584-90. · 2.54 Impact Factor
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  Available from: Yasunori Shintani

  Article: Calcineurin splicing variant calcineurin Aβ1 improves cardiac function after myocardial infarction without inducing hypertrophy.

  Leanne E Felkin, Takuya Narita, Renée Germack, Yasunori Shintani, Kunihiko Takahashi, Padmini Sarathchandra, Marina M López-Olañeta, Jesús M Gómez-Salinero, Ken Suzuki, Paul J R Barton, Nadia Rosenthal, Enrique Lara-Pezzi
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  ABSTRACT: Calcineurin is a calcium-regulated phosphatase that plays a major role in cardiac hypertrophy. We previously described that alternative splicing of the calcineurin Aβ (CnAβ) gene generates the CnAβ1 isoform, with a unique C-terminal region that is different from the autoinhibitory domain present in all other CnA isoforms. In skeletal muscle, CnAβ1 is necessary for myoblast proliferation and stimulates regeneration, reducing fibrosis and accelerating the resolution of inflammation. Its role in the heart is currently unknown. We generated transgenic mice overexpressing CnAβ1 in postnatal cardiomyocytes under the control of the α-myosin heavy chain promoter. In contrast to previous studies using an artificially truncated calcineurin, CnAβ1 overexpression did not induce cardiac hypertrophy. Moreover, transgenic mice showed improved cardiac function and reduced scar formation after myocardial infarction, with reduced neutrophil and macrophage infiltration and decreased expression of proinflammatory cytokines. Immunoprecipitation and Western blot analysis showed interaction of CnAβ1 with the mTOR complex 2 and activation of the Akt/SGK cardioprotective pathway in a PI3K-independent manner. In addition, gene expression profiling revealed that CnAβ1 activated the transcription factor ATF4 downstream of the Akt/mTOR pathway to promote the amino acid biosynthesis program, to reduce protein catabolism, and to induce the antifibrotic and antiinflammatory factor growth differentiation factor 15, which protects the heart through Akt activation. Calcineurin Aβ1 shows a unique mode of action that improves cardiac function after myocardial infarction, activating different cardioprotective pathways without inducing maladaptive hypertrophy. These features make CnAβ1 an attractive candidate for the development of future therapeutic approaches.
  Circulation 06/2011; 123(24):2838-47. · 14.74 Impact Factor