Education 【 display / non-display 】

Education 【 display / non-display 】

• 2003

  -

  2007

  Sapporo Medical University   Graduate School of Medicine  

• 　

  -

  2002

  Hokkaido University   School of Dental Medicine   歯学科  

Degree 【 display / non-display 】

Degree 【 display / non-display 】

• 2007.03   Sapporo Medical University Graduate School of Medicine   Ph.D.

Research Experience 【 display / non-display 】

Research Experience 【 display / non-display 】

• 2023.11

  -

  Now

  Research Institute for Regenerative Medicine, Sapporo Medical University School of Medicine   Department of Tissue Development and Regeneration   Lecturer

• 2019.07

  -

  2023.09

  Research Institute for Frontier Medicine, Sapporo Medical University School of Medicine   Department of Tissue Development and Regeneration   instructor

• 2014

  -

  2019.06

  Sapporo Medical University   School of Medicine   研究員

  研究員

Research Areas 【 display / non-display 】

Research Areas 【 display / non-display 】

• Life sciences   General surgery, pediatric surgery  

• Life sciences   Experimental pathology  

Affiliation 【 display / non-display 】

Affiliation 【 display / non-display 】

• Sapporo Medical University, Graduate School of Medicine   Department of Tissue Development and Regeneration, Research Institute for Regenerative Medicine   Lecturer  

Research Interests 【 display / non-display 】

Research Interests 【 display / non-display 】

• 口腔外科

• スキャフォールド

• 基底膜

• ヒト肝幹細胞

• 共培養

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Papers 【 display / non-display 】

Papers 【 display / non-display 】

• Transplantation of Thy1(+) Cells Accelerates Liver Regeneration by Enhancing the Growth of Small Hepatocyte-Like Progenitor Cells via IL17RB Signaling

  Norihisa Ichinohe, Masayuki Ishii, Naoki Tanimizu, Junko Kon, Yusuke Yoshioka, Takahiro Ochiya, Toru Mizuguchi, Koichi Hirata, Toshihiro Mitaka

  STEM CELLS ( WILEY )  35 ( 4 ) 920 - 931  2017.04  [Refereed]

  Authorship：   Lead author  , Corresponding author

  　View Summary

  Small hepatocyte-like progenitor cells (SHPCs) transiently form clusters in rat livers treated with retrorsine (Ret)/ 70% partial hepatectomy (PH). When Thy1(+) cells isolated from D-galactosamine-treated rat livers were transplanted into the livers of Ret/ PH-treated rats, the mass of the recipient liver transiently increased during the first 30 days after transplantation, suggesting that liver regeneration was enhanced. Here we addressed how Thy1(+) cell transplantation stimulates liver regeneration. We found that the number and size of SHPC clusters increased in the liver at 14 days after transplantation. GeneChip analysis revealed that interleukin 17 receptor b (IL17rb) expression significantly increased in SHPCs from livers transplanted with Thy1(+) cells. We subsequently searched for ligand-expressing cells and found that sinusoidal endothelial cells (SECs) and Kupffer cells expressed Il17b and Il25, respectively. Moreover, extracellular vesicles (EVs) separated from the conditioned medium of Thy1(+) cell culture induced IL17b and IL25 expression in SECs and Kupffer cells, respectively. Furthermore, EVs enhanced IL17rb expression in small hepatocytes (SHs), which are hepatocytic progenitor cells; in culture, IL17B stimulated the growth of SHs. These results suggest that Thy1-EVs coordinate IL17RB signaling to enhance liver regeneration by targeting SECs, Kupffer cells, and SHPCs. Indeed, the administration of Thy1-EVs increased the number and size of SHPC clusters in Ret/ PH-treated rat livers. Sixty days post-transplantation, most expanded SHPCs entered cellular senescence, and the enlarged liver returned to its normal size. In conclusion, Thy1(+) cell transplantation enhanced liver regeneration by promoting the proliferation of intrinsic hepatic progenitor cells via IL17RB signaling.

  DOI PubMed

• CINC-2 and miR-199a-5p in exosomes secreted by transplanted Thy1+ cells activate hepatocytic progenitor cell growth in rat liver regeneration

  Norihisa Ichinohe, Naoki Tanimizu, Keisuke Ishigami, Yusuke Yoshioka, Naoki Fujitani, Takahiro Ochiya, Motoko Takahashi, Toshihiro Mitaka

  Stem Cell Research and Therapy ( Research Square Platform LLC )   2023.05  [Refereed]

  Authorship：   Lead author  , Corresponding author

  　View Summary

  Abstract Background Small hepatocyte-like progenitor cells (SHPCs) are hepatocytic progenitor cells that transiently form clusters in rat livers treated with retrorsine and with 70% partial hepatectomy (PH). We previously reported that transplantation of Thy1⁺ cells derived from d-galactosamine-treated livers promotes SHPC expansion, resulting in the acceleration of liver regeneration. Extracellular vesicles (EVs) produced by Thy1⁺ cells act on sinusoidal endothelial cells (SECs) and Kupffer cells to secrete IL17B and IL25, respectively, resulting in SHPC activation through IL17 receptor B (RB) signaling. Our aim is to identify factors in Thy1-EVs that activate IL17RB signaling.Methods Thy1⁺ cells isolated from rats with d-galactosamine-induced liver injury were cultured for one week. Although some liver stem/progenitor cells proliferated into colonies, others maintained as mesenchymal cells (MCs). Thy1-MCs or Thy1-liver stem/progenitor cells were transplanted into retrorsine/PH-treated livers to examine their effects on SHPCs. SHs isolated from adult rat livers were used to validate factors regulating growth induction.Results The number and size of SHPCs remarkably increased in livers transplanted with Thy1-MCs. Comprehensive analysis of Thy1-MC-EVs revealed that miR-199a-5p, CINC-2, and MCP-1 are candidates for stimulating SHPC growth. Administration of the miR-199a-5p mimic, and not CINC-2, promoted SH growth. SECs treated with CINC-2 induced IL17b expression and their conditioned medium promoted SH growth.Conclusion Thy1-MC transplantation may accelerate liver regeneration due to SHPCs expansion, which is stimulated by CINC-2/IL17RB signaling and miR-199a-5p.

  DOI

• Generation of functional liver organoids on combining hepatocytes and cholangiocytes with hepatobiliary connections ex vivo.

  Naoki Tanimizu, Norihisa Ichinohe, Yasushi Sasaki, Tohru Itoh, Ryo Sudo, Tomoko Yamaguchi, Takeshi Katsuda, Takafumi Ninomiya, Takashi Tokino, Takahiro Ochiya, Atsushi Miyajima, Toshihiro Mitaka

  Nature communications   12 ( 1 ) 3390 - 3390  2021.06  [Refereed]  [International journal]

  　View Summary

  In the liver, the bile canaliculi of hepatocytes are connected to intrahepatic bile ducts lined with cholangiocytes, which remove cytotoxic bile from the liver tissue. Although liver organoids have been reported, it is not clear whether the functional connection between hepatocytes and cholangiocytes is recapitulated in those organoids. Here, we report the generation of a hepatobiliary tubular organoid (HBTO) using mouse hepatocyte progenitors and cholangiocytes. Hepatocytes form the bile canalicular network and secrete metabolites into the canaliculi, which are then transported into the biliary tubular structure. Hepatocytes in HBTO acquire and maintain metabolic functions including albumin secretion and cytochrome P450 activities, over the long term. In this study, we establish functional liver tissue incorporating a bile drainage system ex vivo. HBTO enable us to reproduce the transport of hepatocyte metabolites in liver tissue, and to investigate the way in which the two types of epithelial cells establish functional connections.

  DOI PubMed

• Extracellular vesicles containing miR-146a-5p secreted by bone marrow mesenchymal cells activate hepatocytic progenitors in regenerating rat livers.

  Norihisa Ichinohe, Masayuki Ishii, Naoki Tanimizu, Toru Mizuguchi, Yusuke Yoshioka, Takahiro Ochiya, Hiromu Suzuki, Toshihiro Mitaka

  Stem cell research & therapy   12 ( 1 ) 312 - 312  2021.05  [Refereed]  [International journal]

  Authorship：   Lead author  , Corresponding author

  　View Summary

  BACKGROUND: Small hepatocyte-like progenitor cells (SHPCs) appear to form transient clusters in rat livers treated with retrorsine (Ret) and 70% partial hepatectomy (PH). We previously reported that the expansion of SHPCs was amplified in Ret/PH-treated rat livers transplanted with Thy1+ cells derived from D-galactosamine-treated injured livers. Extracellular vesicles (EVs) produced by hepatic Thy1+ donor cells activated SHPCs via interleukin (IL)-17 receptor B signaling. As bone marrow-derived mesenchymal cells (BM-MCs) also express Thy1, we aimed to determine whether BM-MCs could also promote the growth of SHPCs. METHODS: BM-MCs were isolated from dipeptidyl-peptidase IV (DPPIV)-positive rats. BM-MCs or BM-MC-derived EVs were administered to DPPIV-negative Ret/PH rat livers, and the growth and the characteristics of SHPC clusters were evaluated 14 days post-treatment. miRNA microarrays and cytokine arrays examined soluble factors within EVs. Small hepatocytes (SHs) isolated from an adult rat liver were used to identify factors enhancing hepatocytic progenitor cells growth. RESULTS: The recipient's livers were enlarged at 2 weeks post-BM-MC transplantation. The number and the size of SHPCs increased remarkably in livers transplanted with BM-MCs. BM-MC-derived EVs also stimulated SHPC growth. Comprehensive analyses revealed that BM-MC-derived EVs contained miR-146a-5p, interleukin-6, and stem cell factor, which could enhance SHs' proliferation. Administration of EVs derived from the miR-146a-5p-transfected BM-MCs to Ret/PH rat livers remarkably enhanced the expansion of SHPCs. CONCLUSIONS: miR-146a-5p involved in EVs produced by BM-MCs may play a major role in accelerating liver regeneration by activating the intrinsic hepatocytic progenitor cells.

  DOI PubMed

• Prolonged oxidative stress and delayed tissue repair exacerbate acetaminophen-induced liver injury in aged mice.

  Naoki Tanimizu, Norihisa Ichinohe, Hiromu Suzuki, Toshihiro Mitaka

  Aging   12 ( 19 ) 18907 - 18927  2020.10  [Refereed]  [International journal]

  　View Summary

  The liver gradually loses its regenerative capabilities with aging. However, it remains unknown whether aging affects drug-induced liver injury. Here, we used acetaminophen induced acute liver injury model to compare tissue injury and regeneration of aged mice (>80 weeks old) with young ones (8-10 weeks old). The mortality of aged mice after acetaminophen injury was higher than that of young mice. Transient increase of serum GOT and decrease of reduced glutathione (GSH) were not returned to original levels in aged mice even at 48 hours. In addition, Foxm1b and its targets Ccnd1 and Cdk1 were upregulated in young but not in aged mice after 48 hours. Moreover, an apoptosis-related gene, Cidea, was upregulated specifically in aged livers, which was consistent with increased number of TUNEL+ hepatocytes. Unexpectedly, damaged hepatocytes were retained in aged liver tissue, which may be caused by impaired recruitment of macrophages to the damaged area, without increases in Ccl2 after acetaminophen injury. Collectively, prolonged oxidative stress due to delayed recovery of GSH and the retention of damaged hepatocytes may suppress tissue repair and hepatocyte proliferation, resulting in exacerbation of acetaminophen injury in aged mice. Thus, aging is a risk factor conferring susceptibility against drug-induced liver injury.

  DOI PubMed

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Misc 【 display / non-display 】

Misc 【 display / non-display 】

• Tissue stem cells and tissue repair

  市戸義久, 石井雅之, 谷水直樹, 水口徹, 平田公一, 三高俊広

  Surgery Frontier.   21 ( 3 ) 67 - 69  2014

  Authorship：   Lead author

  Article, review, commentary, editorial, etc. (trade magazine, newspaper, online media)  

• 肝再生における幹細胞の機能

  三高俊広, 市戸義久, 谷水直樹

  肝胆膵   65 ( 1 ) 37 - 46  2012

  Article, review, commentary, editorial, etc. (other)  

• Identification of hepatic oval cells and small hepatocuyes

  市戸義久, 大栄秀和, 谷水直樹, 三高俊広

  再生医学叢書   5 ( 2 ) 102 - 110  2012

  Authorship：   Lead author

  Article, review, commentary, editorial, etc. (other)  

• 肝臓における幹細胞

  市戸義久, 今 純子, 大栄秀和, 三高俊広

  肝胆膵   59 ( 4 ) 573 - 580  2009

  Article, review, commentary, editorial, etc. (other)  

• 肝再生過程における小型肝細胞の役割

  三高俊広, 今 純子, 大栄秀和, 市戸義久

  移植   43 ( 1 ) 2 - 9  2008

  Article, review, commentary, editorial, etc. (other)  

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Research Projects 【 display / non-display 】

Research Projects 【 display / non-display 】

• Development of designer cells for severe liver diseases treatment and analysis of their regeneration mechanism by focusing on tisse stem cells.

  Grant-in-Aid for Scientific Research (C)

  Project Year :

  2023.04

  -

  2026.03

   

  市戸 義久, 三高 俊広

• Renewal of severely damaged livers by activating hepatic progenitor cells

  Grant-in-Aid for Scientific Research (B)

  Project Year :

  2018.04

  -

  2021.03

   

  MITAKA Toshihiro

  　View Summary

  Small hepatocytes (SHs) are a subpopulation of mature hepatocytes that can act as hepatocytic progenitor cells. Hepatocytic parental progenitor cells (HPPCs) exist among SHs. In this study we demonstrated that the self-renewal ability of HPPCs depended on laminin111 through integrin beta1 signaling. In addition, we succeeded in generating a hepatobiliary tubular organoid using mouse hepatocytic progenitor cells and cholangiocytes. Hepatocytes form the bile canalicular network and secret metabolites into the canaliculi, which are then transported into the biliary tubular structure. Transplantation of bone marrow-derived mesenchymal cells (BM-MCs) enhanced the regeneration of retrorsine/PH (Ret/PH) model rat livers. Small hepatocyte-like progenitor cells (SHPCs) are intrinsic hepatic progenitor cells appeared in Ret/PH-treated livers. Administration of BM-MC-derived extracellular vesicles containing miR-146a-5p, interleukin 6, and stem cell factor could enhance the growth of SHPCs.

• In vitro reconstruction of hepatic tissue

  Grant-in-Aid for Challenging Research (Exploratory)

  Project Year :

  2017.06

  -

  2019.03

   

  Mitaka Toshihiro

  　View Summary

  We developed the method to reconstruct hepatic organoids consisting of mouse hepatocytes and cholangiocytes, which could drain bile juice into bile ducts from bile canaliculi formed by hepatocytes. Cholangiocytes are cultured on collagen gel and then hepatocytes are added. After collagen gel containing Matrigel is overlaid on the cells, hepatic organoids with the connections between bile canaliculi and bile ducts are formed within 2 weeks. Hepatocytic parental progenitor cells (HPPCs) with self-renewal capability exist in a population of small hepatocytes, which is a subpopulation of mature hepatocytes. HPPCs could be passaged several times with maintaining their abilities of basic hepatic functions and production of progeny. Self-renewal capability of HPPCs is maintained when they are cultured on laminin 111, which transduces the signal via integrin beta1.

• Translational research for clinical apply using liver stem cells from cell banking

  Grant-in-Aid for Scientific Research (C)

  Project Year :

  2017.04

  -

  2020.03

   

  MIZUGUCHI TORU

  　View Summary

  We established a method to identify and separate liver stem cells from CD45-, TER119-, CD31-, EpCAM-negative, and ICAM-1-positive cells as donor cells for hepatocyte-transplantation. From this cell population, cloned liver stem cells were established. Besides, donor cells treated with oncostatin M had improved regeneration replacement efficiency. Twenty-five studies targeting liver volume assessment were collected and reviewed to improve donor collection efficiency. When projected on a three-dimensional scatter plot as a standard liver volume calculation method, it was found that it was classified into two clusters. The involvement of the structural variant of laminin could be on the self-renewal performance of the parental progenitor cells. When hyaluronic acid was used as a substrate, CD44-positive small hepatocytes proliferated, and the cell recovery rate and the retransplantation rate were improved under the conditions using Matrigel as a substrate.

• Analysis of immunoregulation and mechanism of liver regeneration in cell transplantation

  Grant-in-Aid for Scientific Research (C)

  Project Year :

  2017.04

  -

  2020.03

   

  Norihisa Ichinohe

  Authorship： Principal investigator

  　View Summary

  Small hepatocyte-like progenitor cells (SHPCs) transiently appear in rat livers treated with retrorsine (Ret)/70% partial hepatectomy (PH). We reported that transplantation of Thy1+ cells derived from galactosamine-treated liver accelerated the growth of SHPCs in Ret/PH-treated rat livers. Extracellular vesicles (EVs) produced by Thy1+ donor cells activated SHPCs. As bone marrow-derived mesenchymal cells (BM-MCs) also express Thy1, we investigated whether BM-MCs could promote the growth of SHPCs as well as hepatic Thy1+ cells. EVs isolated from conditioned medium of cultured BM-MCs were administrated into Ret/PH-treated rat livers, resulting in the growth of SHPCs. Soluble factors contained in EVs were examined and we identified that miRNA146a is the most important factor for enhancing the proliferation of cultured small hepatocytes (SHs). EVs derived from BM-MCs carry miR146a into SHPCs for activating their growth capacity.

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