Yukiteru Ouji

Potential Use of Embryonic Stem Cells for the Treatment of Mouse Parkinsonian Models: Improved Behavior by Transplantation of In Vitro Differentiated Dopaminergic Neurons from Embryonic Stem Cells

Background and Aims. The purpose of the present study was to examine the efficacy of transplantation of mouse embryonic‐stem‐(ES)‐cell‐derived tyrosine hydroxylase‐positive (TH+) cells into Parkinsonian mice using behavioral tests and immunohistochemical evaluation.

A Novel Human AlkB Homologue, ALKBH8, Contributes to Human Bladder Cancer Progression

We recently identified a novel human AlkB homologue, ALKBH8, which is expressed in various types of human cancers including human urothelial carcinomas. In examining the role and function of ALKBH8 in human bladder cancer development in vitro, we found that silencing of ALKBH8 through small interfering RNA transfection reduced reactive oxygen species (ROS) production via down-regulation of NAD(P)H oxidase-1 (NOX-1) and induced apoptosis through subsequent activation of c-jun NH(2)-terminal kinase (JNK) and p38. However, we also found that JNK and p38 activation resulted in phosphorylation of H2AX (gammaH2AX), a variant of mammalian histone H2A, which contributes to the apoptosis induced by silencing ALKBH8 and NOX-1. Silencing of ALKBH8 significantly suppressed invasion, angiogenesis, and growth of bladder cancers in vivo as assessed both in the chorioallantoic membrane assay and in an orthotopic mouse model using green fluorescent protein-labeled KU7 human urothelial carcinoma cells. Immunohistochemical examination showed high expression of ALKBH8 and NOX-1 proteins in high-grade, superficially and deeply invasive carcinomas (pT(1) and >pT(2)) as well as in carcinoma in situ, but not in low-grade and noninvasive phenotypes (pT(a)). These findings indicate an essential role for ALKBH8 in urothelial carcinoma cell survival mediated by NOX-1-dependent ROS signals, further suggesting new therapeutic strategies in human bladder cancer by inducing JNK/p38/gammaH2AX-mediated cell death by silencing of ALKBH8.

Cotransplantation of mouse embryonic stem cells and bone marrow stromal cells following spinal cord injury suppresses tumor development.

Embryonic stem (ES) cells are a potential source for treatment of spinal cord injury (SCI). Although one of the main problems of ES cell-based cell therapy is tumor formation, there is no ideal method to suppress tumor development. In this study, we examined whether transplantation with bone marrow stromal cells (BMSCs) prevented tumor formation in SCI model mice that received ES cell-derived grafts containing both undifferentiated ES cells and neural stem cells. Embryoid bodies (EBs) formed in 4-day hanging drop cultures were treated with retinoic acid (RA) at a low concentration of 5 × 10–9 M for 4 days, in order to allow some of the ES cells to remain in an undifferentiated state. RA-treated EBs were enzymatically digested into single cells and used as ES cell-derived graft cells. Mice transplanted with ES cell-derived graft cells alone developed tumors at the grafted site and behavioral improvement ceased after day 21. In contrast, no tumor development was observed in mice cotransplanted with BMSCs, which also showed sustained behavioral improvement. In vitro results demonstrated the disappearance of SSEA-1 expression in cytochemical examinations, as well as attenuated mRNA expressions of the undifferentiated markers Oct3/4, Utf1, Nanog, Sox2, and ERas by RT-PCR in RA-treated EBs cocultured with BMSCs. In addition, MAP2-immunopositive cells appeared in the EBs cocultured with BMSCs. Furthermore, the synthesis of NGF, GDNF, and BDNF was confirmed in cultured BMSCs, while immunohistochemical examinations demonstrated the survival of BMSCs and their maintained ability of neurotrophic factor production at the grafted site for up to 5 weeks after transplantation. These results suggest that BMSCs induce undifferentiated ES cells to differentiate into a neuronal lineage by neurotrophic factor production, resulting in suppression of tumor formation. Cotransplantation of BMSCs with ES cell-derived graft cells may be useful for preventing the development of ES cell-derived tumors.

Role of syndecan-1 (CD138) in cell survival of human urothelial carcinoma

Heparan sulfate proteoglycan syndecan‐1, CD138, is well known to be associated with cell proliferation, adhesion, and migration in various types of malignancies. In the present study, we focused on the role of syndecan‐1 in human urothelial carcinoma of the urinary bladder. Silencing of syndecan‐1 by siRNA transfection down‐regulated transcriptional factor junB and the long isoform of FLICE‐inhibitory protein (FLIP long), resulting in the induction of apoptosis in the urothelial carcinoma cell lines UMUC2 and UMUC3. Knockdown of junB and FLIP long as well as syndecan‐1 silencing mediated apoptosis that was inhibited by pan‐caspase inhibitors. Transurethral injection of syndecan‐1 siRNA into the urinary bladder significantly reduced syndecan‐1 gene expression and growth of red fluorescent‐labeled KU‐7/RFP bladder cancer cells in the mouse orthotopic bladder cancer model. Immunohistochemical examination showed high syndecan‐1 protein expression in high‐grade, superficial, and deep invasive carcinomas (pT1 and ≥pT2) as well as carcinoma in situ, but not in low‐grade and noninvasive phenotypes (pTa). In addition, the percentage of cancer cells positive for syndecan‐1 at initial diagnosis was statistically associated with the frequency of bladder cancer recurrence after transurethral resection. In conclusion, syndecan‐1 might contribute to urothelial carcinoma cell survival and progression; therefore, this molecule could be a new therapeutic target in human urinary bladder cancer. (Cancer Sci 2009)

Embryonic stem cells reduce liver fibrosis in CCl4-treated mice.

We transplanted undifferentiated embryonic stem (ES) cells into the spleens of carbon tetrachloride (CCl4)‐treated mice to determine their effects on liver fibrosis. Carbon tetrachloride at 0.5 ml/kg of body weight was injected intraperitoneally into C57BL/6 mice twice weekly for up to 20 weeks. Four weeks after the first injection, the mice were divided into two groups and those in group 1 received 1 × 105 ES cells genetically labelled with enhanced green fluorescent protein (GFP) in the spleens, while group 2 mice received 0.1 ml of phosphate‐buffered saline. In group 1, GFP‐immunopositive cells were retained and found in areas of fibrosis in the liver, and reduced liver fibrosis was observed as compared with group 2. Secondary transplantation of ES cells at 12 weeks after the initial transplantation enhanced the reduction in liver fibrosis. No teratoma formation or uncontrolled growth of ES cells in organs, including the liver and spleen, was observed in any of the mice. In the livers of group 1 mice, metalloproteinase 9‐immunopositive cells derived from ES cells as well as those from the recipient were observed. These cells were also found to be immunopositive for the hepatoblast marker Delta‐like (DlK‐1), a member of the DlK‐1 family of transmembrane proteins. These results suggest that ES‐based cell therapy is potentially useful for liver fibrosis treatment and that reduction in CCl4‐induced liver fibrosis by transplantation of ES cells may be related closely to the emergence of metalloproteinase‐producing hepatoblast‐like cells.

A familial case of visceral toxocariasis due to consumption of raw bovine liver

We present 3 adult cases of visceral toxocariasis from the same family, who each consumed thin slices of raw bovine liver weekly, and developed eosinophilia and multiple small lesions in their livers and lungs. Serological examinations using the larval excretory-secretory product of Toxocara canis strongly indicated infection with Toxocara species larvae. The patients responded well to treatment with albendazole. Ingestion of raw liver from paratenic animals is considered to be a common transmission route of human toxocariasis, especially in adults.

Syndecan-1, a new target molecule involved in progression of androgen-independent prostate cancer.

Heparan sulfate proteoglycan syndecan‐1 (CD138) is well known to be associated with cell proliferation, adhesion and migration in various types of malignancies. In the present study, we focused on the role of syndecan‐1 in human prostate cancer. Immunohistochemical analysis revealed either no or rare expression of syndecan‐1 in normal secretory glands and prostate cancer cells at hormone naïve status, whereas the expression was significantly increased in viable cancer cells following neo‐adjuvant hormonal therapy. Syndecan‐1 expression was much higher in the androgen independent prostate cancer cell lines DU145 and PC3, rather than the androgen‐dependent LNCaP, but the level in LNCaP was up‐regulated in response to long‐term culture under androgen deprivation. Silencing of syndecan‐1 by siRNA transfection reduced endogenous production of reactive oxygen species through down‐regulating NADPH oxidase 2 and induced apoptosis in DU145 and PC3 cells. Consistently, NADPH oxidase 2 knockdown induced apoptosis to a similar extent. Subcutaneous inoculation of PC3 cells in nude mice demonstrated the reduction of tumor size by localized injection of syndecan‐1 siRNA in the presence of atelocollagen. Moreover, the mouse model and chorioallantoic membrane assay demonstrated significant inhibition of vascular endothelial growth factor and tumor angiogenesis by silencing of syndecan‐1. In conclusion, syndecan‐1 might participate in the process of androgen‐dependent to ‐independent conversion, and be a new target molecule for hormone resistant prostate cancer therapy. (Cancer Sci 2009; 100: 1248–1254)

In vitro differentiation of hepatocyte-like cells from embryonic stem cells promoted by gene transfer of hepatocyte nuclear factor 3 β

We investigated the ability of a genetically altered embryonic stem (ES) cell line to promote endodermal differentiation toward hepatocytes in vitro by transfecting the hepatocyte nuclear factor-3beta (HNF-3beta) gene. Parental and HNF-3beta-transfected ES cells were initiated toward differentiation in embryoid bodies (EBs) for 5 days and the resulting EBs were transferred to an attached culture system. Albumin production was observed using an immuno-cytochemical method 7 days after induction of differentiation in almost all differentiating HNF-3beta-transfected ES cells, whereas scant immuno-reactivity against albumin was found on the same day in the cultures of differentiating parental ES cells. An analysis using a reverse transcriptase polymerase chain reaction revealed the HNF-4alpha expression in the HNF-3beta-transfected ES cells and also demonstrated that the expression of endodermal and hepatocyte-related markers, such as transthyretin, alpha-fetoprotein, albumin, alpha-1 antitrypsin, tryptophan-2,3-dioxygenase and phosphoenol-pyruvate carboxykinase, could be observed at an early stage in the outgrowths of HNF-3beta-transfected ES cells compared to the parental ES cells. These results suggest that HNF-3beta-transfected ES cells may be useful for the efficient induction of hepatocytes in vivo.

In vitro differentiation of mouse embryonic stem cells into inner ear hair cell-like cells using stromal cell conditioned medium

Hearing loss is mainly caused by loss of sensory hair cells (HCs) in the organ of Corti or cochlea. Although embryonic stem (ES) cells are a promising source for cell therapy, little is known about the efficient generation of HC-like cells from ES cells. In the present study, we developed a single-medium culture method for growing embryoid bodies (EBs), in which conditioned medium (CM) from cultures of ST2 stromal cells (ST2-CM) was used for 14-day cultures of 4-day EBs. At the end of the 14-day cultures, up to 20% of the cells in EB outgrowths expressed HC-related markers, including Math1 (also known as Atoh1), myosin6, myosin7a, calretinin, α9AchR and Brn3c (also known as Pou4f3), and also showed formation of stereocilia-like structures. Further, we found that these cells were incorporated into the developing inner ear after transplantation into chick embryos. The present inner ear HC induction method using ST2-CM (HIST2 method) is quite simple and highly efficient to obtain ES-derived HC-like cells with a relatively short cultivation time.

Canonical Wnts, specifically Wnt-10b, show ability to maintain dermal papilla cells

Although Wnts are expressed in hair follicles (HFs) and considered to be crucial for maintaining dermal papilla (DP) cells, the functional differences among them remain largely unknown. In the present study, we investigated the effects of Wnts (Wnt-3a, 5a, 10b, 11) on the proliferation of mouse-derived primary DP cells in vitro as well as their trichogenesis-promoting ability using an in vivo skin reconstitution protocol. Wnt-10b promoted cell proliferation and trichogenesis, while Wnt-3a showed those abilities to a limited extent, and Wnt-5a and 11 had no effects. Furthermore, we investigated the effects of these Wnts on cultured DP cells obtained from versican-GFP transgenic mice and found that Wnt-10b had a potent ability to sustain their GFP-positivity. These results suggest that canonical Wnts, specifically Wnt-10b, play important roles in the maintenance of DP cells and trichogenesis.