久米 晃啓

Background Mesenchymal stein cells (MSCs) are a promising vehicle for targeted cancer gene therapy because of their potential of tumor tropism. For efficient therapeutic application, we developed retroviral vector-producing MSCs that enhance tumor transduction via progeny vector production. Methods Rat bone marrow-derived MSCs were nucleofected with the proviral plasmids (vesicular stomatitis virus-G protein-pseudotyped retroviral vector components) (VP-MSCs) or pLTR plasmid alone (non-VP-MSCs). The luciferase-based in vivo imaging system was used to assess gene expression periodically. To evaluate the anticancer effects, we administered MSCs expressing herpes simplex virus-thymidine kinase (HSV-tk) into the left ventricular cavity of nude mice engrafted with 9L glioma cells subcutaneously. Results In vivo imaging revealed that administration of luciferase-expressing non-VP-MSCs enhanced the bioluminescence signal at the inoculation sites of 9L cells, whereas no accumulation was observed in juice at the site of the control Rat-1 fibroblasts. Compared to non-VP-MSCs, the administration of VP-MSCs resulted in significant augmentation of the signal with an increase in transgene copy number. Immunohistochemical analysis showed marked luciferase expression at the tumor periphery in mice injected with VP-MSCs, whereas little expression was detected in those in injected. with non-VP-MSCs. Under the continuous infusion of ganciclovir systemic, administration of VP-MSCs expressing HSV-tk Suppressed tumor growth more effectively than non-VP-MSC administration, whereas no anticancer effect was observed Without ganciclovir treatment. Furthermore, VP-MSC administration caused no transgene transduction in the normal tissues and organs. Conclusions VP-MSCs accumulated at the site of tumors after intravascular injection in tumor-bearing mice, followed by in situ gene transfer to tumors without transduction of normal organs. When applied to the HSV-tk/ganciclovir suicide gene therapy, more efficient tumor growth Suppression was observed using VP-MSCs compared to non-VP-MSCs. This VP-MSC-based system has great potential for improved cancer gene therapy. Copyright (C) 2009 John Wiley & Sons, Ltd.

Regions required for chicken glycine decarboxylase gene transcription were examined. A region between -82 and +22 (-82/+22) with motifs similar to binding sites for Sp1, NF-Y and CP2 was assigned to the proximal promoter active in both chicken hepatoma cell line, LMH, and hepatocytes in primary culture. In LMH cells, a genomic region, KX, between Kpn1 (-4155) and Xbal (-2113) sites changed promoter activity with the aid of four additional genomic regions termed upstream regulator regions for suppression (UpRS) and activation (UpRA) of transcription. Those precise segments are UpR1S (-376/-346), UpR1A (-345/-291), UpR2S (-137/-108) and UpR2A (-107/-83). Within KX, -4155/-3605 activates and -3604/-3367 suppresses the promoter. -3366/-3024 activates or suppresses the promoter, probably with different UpR counterparts. -2197/-2113 restores the actions of -3366/-3024. While in LMH cells, the upstream UpRs abrogate the functions of immediately downstream UpRs, UpR1S or UpR2S or both may be at least less active in hepatocytes than in LMH cells. Nuclear extracts from various chicken tissues and LMH cells had UpR2A binding proteins in different populations, suggesting that together with the UpRs, the segments in KX are involved in the regulation of cell type-specific transcription of this gene. (c) 2008 Elsevier B.V. All rights reserved.

We investigated a fabrication process and optical properties of electro-optic (EO) light modulators with Fabry-Perot structure, which consisted of PLZT [(Pb 0.91,La 009)(Zr 0 65,Ti 0,35)O 3] thick films by aerosol deposition method. A supernatant elimination process for small size PLZT powder with diameter of 0.125-0.175 μm was effective in order to obtain a transparent film. In the fabricated Fabry-Perot type EO light modulator with a ITO (Indium Tin Oxide))/PLZT/ITO defect layer, a wavelength of resonant localized mode was shifted about 1.0 nm from 788 nm by applying an electric field of+400 kV/cm in reflectance mode, and consequently the reflectance difference of 7.2 % was observed. The Fabry-Perot type EO light modulator had the advantage of contrast of light in the reflection mode. © 2009 The Institute of Electrical Engineers of Japan.

Mesenchymal stem cells (MSCs) are considered to be a promising platform for cell and gene therapy for a variety of diseases. First, in the field of hematopoietic stem cell transplantation, there are two applications of MSCs: 1) the improvement of stem cell engrafting and the acceleration of hematopoietic reconstitution based on the hematopoiesis-supporting ability; and 2) the treatment of severe graft-versus-host disease (GVHD) based on the immunomodulatory ability. Regarding the immunosuppressive ability, we found that nitric oxide (NO) is involved in the MSC-mediated suppression of T cell proliferation. Second, tumor-bearing nude mice were injected with luciferase-expressing MSCs. An in vivo imaging analysis showed the significant accumulation of the MSCs at the site of tumors. The findings suggest that MSCs can be utilized to target metastatic tumors and to deliver anti-cancer molecules locally. As the third application, MSCs may be utilized as a cellular vehicle for protein-supplement gene therapy. When long-term transgene expression is needed, a therapeutic gene should be introduced with a minimal risk of insertional mutagenesis. To this end, site-specific integration into the AAVS 1 locus on the chromosome 19 (19q13.4) by using the integration machinery of adeno-associated virus (AAV) would be particularly valuable. There will be wide-ranging applications of MSCs to frontier medical treatments in the near future. (C) 2008 Elsevier Ltd. All rights reserved.

Background Inflammation plays an important role in the pathogenesis of hypertension and hypertensive organ damage. Interleukin (IL)-10, a pleiotropic anti-inflammatory cytokine, exerts vasculoprotective effects in many animal models. In the present study, we examined the preventive effects of adeno-associated virus (AAV) vector-mediated sustained IL-10 expression against hypertensive heart disease and renal dysfunction in Dahl salt-sensitive rats. Methods We injected the rats intramuscularly with an AAV type I-based vector encoding rat IL-10 or enhanced green fluorescent protein (EGFP) at 5 weeks of age; subsequently, the rats were fed a high-sodium diet from 6 weeks of age. Results Sustained IL-10 expression significantly improved survival rate of Dahl salt-sensitive rats compared with EGFP expression (62.5% versus 0%, p < 0.001); it also caused 26.0% reduction in systolic blood pressure at 15 weeks (p < 0.0001). Echocardiography exhibited a 22.0% reduction in hypertrophy (p < 0.0001) and a 26.3% improvement in fractional shortening (p < 0.0001) of the rat left ventricle in the IL-10 group compared to the EGFP group. IL-10 expression also caused a 21.7% decrease in the heart weight/body weight index and cardiac atrial natriuretic peptide levels. Histopathological studies revealed that IL-10 decreased inflammatory cell infiltration, fibrosis, and transforming growth factor-P, levels in the failing heart. Furthermore, IL-10 expression significantly reduced urine protein excretion with increased glomerular filtration rates. Conclusions This is the first study to demonstrate that the anti-inflammatory cytokine IL-10 has a significant anti-hypertensive effect. AAV vector-mediated IL-10 expression potentially prevents the progression of refractory hypertension and hypertensive organ damage in humans. Copyright (c) 2008 John Wiley & Sons, Ltd.

Since standard aminoglycoside treatment progressively causes hearing disturbance with hair cell degeneration, systemic use of the drugs is limited. Adeno-associated virus (AAV)-based vectors have been of great interest because they mediate stable transgene expression in a variety of postmitotic cells with minimal toxicity. In this study, we investigated the effects of regulated AAV1-mediated glial cell line-derived neurotrophic factor (GDNF) expression in the cochlea on aminoglycoside-induced damage. AAV1-based vectors encoding GDNF or vectors encoding GDNF with an rtTA2s- S2 Tet- on regulation system were directly microinjected into the rat cochleae through the round window at 5 x 10(10) genome copies/body. Seven days after the virus injection, a dose of 333 mg/kg of kanamycin was subcutaneously given twice daily for 12 consecutive days. GDNF expression in the cochlea was confirmed and successfully modulated by the Tet-on system. Monitoring of the auditory brain stem response revealed an improvement of cochlear function after GDNF transduction over the frequencies tested. Damaged spiral ganglion cells and hair cells were significantly reduced by GDNF expression. Our results suggest that AAV1-mediated expression of GDNF using a regulatedexpression system in the cochlea is a promising strategy to protect the cochlea from aminoglycoside-induced damage.

Since standard aminoglycoside treatment progressively causes hearing disturbance with hair cell degeneration, systemic use of the drugs is limited. Adeno-associated virus (AAV)-based vectors have been of great interest because they mediate stable transgene expression in a variety of postmitotic cells with minimal toxicity. In this study, we investigated the effects of regulated AAV1-mediated glial cell line-derived neurotrophic factor (GDNF) expression in the cochlea on aminoglycoside-induced damage. AAV1-based vectors encoding GDNF or vectors encoding GDNF with an rtTA2s- S2 Tet- on regulation system were directly microinjected into the rat cochleae through the round window at 5 x 10(10) genome copies/body. Seven days after the virus injection, a dose of 333 mg/kg of kanamycin was subcutaneously given twice daily for 12 consecutive days. GDNF expression in the cochlea was confirmed and successfully modulated by the Tet-on system. Monitoring of the auditory brain stem response revealed an improvement of cochlear function after GDNF transduction over the frequencies tested. Damaged spiral ganglion cells and hair cells were significantly reduced by GDNF expression. Our results suggest that AAV1-mediated expression of GDNF using a regulatedexpression system in the cochlea is a promising strategy to protect the cochlea from aminoglycoside-induced damage.

The ST2 gene produces a soluble secreted form and a transmembrane form, referred to as soluble ST2 and ST2L, respectively. A recent study has reported that interleukin (IL)-33 is a specific ligand of ST2L and induces production of T helper type 2 (Th2) cytokines. Although soluble ST2 is highly produced in sera of asthmatic patients and plays a critical role for production of Th2 cytokines, the function of soluble ST2 in relation to IL-33 signaling remains unclear. Here we show antagonistic effects of soluble ST2 on IL-33 signaling using a murine thymoma EL-4 cells stably expressing ST2L and a murine model of asthma. Soluble ST2 directly bound to IL-33 and suppressed activation of NF-kappa B in EL-4 cells stably expressing ST2L, suggesting that the complex of soluble ST2 and IL-33 fails to bind to ST2L. In a murine model of asthma, pretreatment with soluble ST2 reduced production of IL-4, IL-5, and IL-13 from IL-33-stimulated splenocytes. These results indicate that soluble ST2 acts as a negative regulator of Th2 cytokine production by the IL-33 signaling. Our study provides a molecular mechanism wherein soluble ST2 modulates the biological activity of IL-33 in allergic airway inflammation.

Prostacyclin synthase (PGIS) is the final committed enzyme in the metabolic pathway of prostacyclin production. The therapeutic option of intravenous prostacyclin infusion in patients with pulmonary arterial hypertension is limited by the short half-life of the drug and life-threatening catheter-related complications. To develop a better delivery system for prostacyclin, we examined the feasibility of intramuscular injection of an adenoassociated virus (AAV) vector expressing PGIS for preventing monocrotaline-induced pulmonary arterial hypertension in rats. We developed an AAV serotype 1-based vector carrying a human PGIS gene (AAV-PGIS). AAV-PGIS or the control AAV vector expressing enhanced green fluorescent protein was injected into the anterior tibial muscles of 3-week-old male Wistar rats; this was followed by the monocrotaline administration at 7 weeks. Eight weeks after injecting the vector, the plasma levels of 6-keto-prostaglandin F-1 alpha increased in a vector dose-dependent manner. At this time point, the PGIS transduction (1x10(10) genome copies per body) significantly decreased mean pulmonary arterial pressure (33.9 +/- 2.4 versus 46.1 +/- 3.0 mm Hg; P < 0.05), pulmonary vascular resistance (0.26 +/- 0.03 versus 0.41 +/- 0.03 mm Hg . mL(-1) . min(-1) . kg(-1); P < 0.05), and medial thickness of the peripheral pulmonary artery (14.6 +/- 1.5% versus 23.5 +/- 0.5%; P < 0.01) as compared with the controls. Furthermore, the PGIS-transduced rats demonstrated significantly improved survival rates as compared with the controls (100% versus 50%; P < 0.05) at 8 weeks postmonocrotaline administration. An intramuscular injection of AAV-PGIS prevents monocrotaline-pulmonary arterial hypertension in rats and provides a new therapeutic alternative for preventing pulmonary arterial hypertension in humans.

Pulmonary arterial hypertension (PAH) is a fatal disease associated with inflammation and pathological remodeling of the pulmonary artery (PA). Interleukin (IL)-10 is a pleiotropic antiinflammatory cytokine with vasculoprotective properties. Here, we report the preventive effects of IL-10 on monocrotaline-induced PAH. Three-week-old Wistar rats were intramuscularly injected with an adeno-associated virus serotype 1 vector expressing IL-10, followed by monocrotaline injection at 7 weeks old. IL-10 transduction significantly improved survival rates of the PAH rats 8 weeks after monocrotaline administration compared with control gene transduction (75% versus 0%, P < 0.01). IL-10 also significantly reduced mean PA pressure (22.8 +/- 1.5 versus 29.7 +/- 2.8 mm Hg, P < 0.05), a weight ratio of right ventricle to left ventricle plus septum (0.35 +/- 0.04 versus 0.42 +/- 0.05, P < 0.05), and percent medial thickness of the PA (12.9 +/- 0.3% versus 21.4 +/- 0.4%, P < 0.01) compared with controls. IL-10 significantly reduced macrophage infiltration and vascular cell proliferation in the remodeled PA in vivo. It also significantly decreased the lung levels of transforming growth factor-beta(1) and IL-6, which are indicative of PA remodeling. In addition, IL-10 increased the lung level of heme oxygenase-1, which strongly prevents PA remodeling. In vitro analysis revealed that IL-10 significantly inhibited excessive proliferation of cultured human PA smooth muscle cells treated with transforming growth factor-beta(1) or the heme oxygenase inhibitor tin protoporphyrin IX. Thus, IL-10 prevented the development of monocrotaline-induced PAH, and these results provide new insights into the molecular mechanisms of human PAH.

Site-specific integration of the therapeutic transgene is favorable for gene therapy applications since it minimizes the risk of insertional mutagenesis and thereby prevents target cells from developing tumors. Adeno-associated virus (AAV), a member of parvovirus, is unique in that it integrates its genome into a specific site termed the AAVS1 locus (19q13.4) in the human genome. A non-structural replication initiator protein of AAV, Rep78 or Rep68, binds the inverted terminal repeat (ITR) sequence at either end of the AAV genome via tandem repeats of the GAGC/GCTC motif. A homologous sequence exists at theAAVS1 site. The Rep protein recognizes it and drives the integration of theAAVgenome intoAAVS1. The ITR is a cis element sufficient for AAVS1-specific integration. The incorporation of the ITR sequence into plasmidDNAis thus discussed in terms of Rep-mediated sitespecific integration and of AAVS1 as a hazard-free target for transgene integration. Therefore, the use of the AAV integration machinery should allow us to develop a safer gene delivery system.

BACKGROUND: In vivo expansion of gene-modified cells would be a promising approach in the field of hematopoietic stem cell gene therapy. To this end, we previously developed a selective amplifier gene (SAG), a chimeric gene encoding the granulocyte colony-stimulating factor (G-CSF) receptor (GCR), as a growth-signal generator and the hormone-binding domain of the steroid receptor as a molecular switch. We have already reported that hematopoietic cells retrovirally transduced with the SAG can be expanded in a steroid-dependent manner in vitro and in vivo in mice and nonhuman primates. In this study, we have developed a new-generation SAG, in which the erythropoietin (EPO) receptor (EPOR) is utilized instead of the steroid receptor as a molecular switch. METHODS: Two EPO-driven SAGs were constructed, EPORGCR and EPORMpl, containing the GCR and c-Mpl as a signal generator, respectively. First, to compare the steroid-driven and EPO-driven SAGs, Ba/F3 cells were transduced with these SAGs. Next, to examine whether GCR or c-Mpl is the more suitable signal generator of the EPO-driven SAG, human cord blood CD34(+) cells were transduced with the two EPO-driven SAGs (EPORMpl and EPORGCR). Finally, we examined the in vivo efficacy of EPORMpl in mice. Irradiated mice were transplanted with EPORMpl-transduced bone marrow cells followed by administration of EPO. RESULTS: The EPO-driven SAGs were shown to induce more rapid and potent proliferation of Ba/F3 cells than the steroid-driven SAGs. The EPORMpl induced more efficient EPO-dependent proliferation of the human cord blood CD34(+) cells than the EPORGCR in terms of total CD34(+) cell, c-Kit(+) cell, and clonogenic progenitor cell (CFU-C) numbers. In the transplanted mice the transduced peripheral blood cells significantly increased in response to EPO. CONCLUSIONS: The new-generation SAGs, especially EPORMpl, are able to efficiently confer an EPO-dependent growth advantage on transduced hematopoietic cells in vitro and in vivo in mice.

We previously developed "selective amplifier genes (SAGs)" which confer a growth advantage to transduced cells. The SAG is a chimeric gene encoding the G-CSF receptor (GCR) and the estrogen or tamoxifen (Tm) receptor and is able to expand transduced hematopoietic cells by treatment with estrogen or Tm. In the current study, we examined the in vitro efficacy of modified SAGs containing the thrombopoietin (TPO) receptor (c-Mpl) gene instead of GCR as a more potent signal generator. In addition, we constructed various mutant Mpl-type SAGs to abolish the responsiveness to endogenous TPO while retaining Tm-dependency. When Ba/F3 cells were retrovirally transduced with the Mpl-type SAGs, the cells showed Tm- and TPO-dependent growth even without IL-3. The Mpl-type SAGs induced more potent proliferation of Ba/F3 and cynomolgus CD34(+) cells than the GCR-type SAG. One mutant Mpl-type SAG (Delta GCRMplTmR) successfully lost the responsiveness to TPO without affecting the Tm-dependence.

BACKGROUND: Composite tissue allografts are unique because they provide the vascularized bone marrow with stroma, which is the supportive microenvironment. In this study, we investigated the beneficial effect of donor-derived bone marrow cells within the long-surviving recipient rats after limb transplantation. METHODS: Green fluorescent protein (GFP) transgenic rats developed for paramount cell marking were donors, and wild Wistar rats were recipients. Orthotopic hind-limb transplantation was performed using a microsurgical technique. Tacrolimus (1.0 mg/kg) was intramuscularly injected for 14 days postoperatively. The skin graft from GFP donor onto the GFP recipient was performed as a control. Flow cytometric analyses of recipient peripheral blood and bone marrow were carried out at 4 to 6 days, 18 to 21 days, 6 weeks, and 2, 4, 6, 9, and 12 months after transplantation. RESULTS: The rats that received tacrolimus therapy achieved prolonged composite graft acceptance more than 12 months, whereas GFP skin grafts were rejected at 47 days under the same immunosuppressive protocol. Numerous GFP lymphocytes and granulocytes were detected within the recipient bone marrow for the first 6 weeks post limb transplantation. These cells remained relatively stable for more than 12 months. CONCLUSIONS: The results showed that donor-derived hematopoietic stem cells engrafted in recipient bone marrow and differentiated to lymphocytes and granulocytes after limb transplantation. The vascularized bone marrow, transplanted as a part of the hind limb, could have contributed to mixed chimerism and worked as the bone-marrow source in the recipients.

The cytokine receptor common gamma chain (gammac) plays a pivotal role in transmitting multiple interleukin signals. Its gene mutations cause profound lymphoid maldevelopment, a disorder known as X-linked severe combined immunodeficiency (X-SCID). Without successful bone marrow transplantation, affected patients would die in infancy or early childhood due to severe and recurrent infections. Therefore, development of gene therapy strategies has been awaited for those without suitable marrow donors. We constructed a retrovirus vector carrying the gammac and the enhanced green fluorescent protein (EGFP) genes for a preclinical study with a murine X-SCID model. After transduction of X-SCID bone marrow and infusion into myeloablated X-SCID recipients, robust lymphoid reconstitution was observed in all the examined lymphocyte subsets such as CD4(+)-T, CD8(+)-T, B and NK cells. A long-term EGFP expression was demonstrated in both lymphoid and myeloid cells, suggesting that this type of vector is useful in evaluating regimens of stem cell-directed gene therapy.

Background The green fluorescent protein (GFP) has proven a useful marker in retroviral gene transfer studies targeting hematopoietic stem cells (HSCs) in mice. However, several investigators have reported very low in vivo peripheral blood marking levels in nonhuman primates after transplantation of HSCs transduced with the GFP gene. We retrovirally marked cynomolgus monkey HSCs with the GFP gene, and tracked in vivo marking levels within both bone marrow progenitor cells and mature peripheral blood cells following autologous transplantation after myeloablative conditioning. Methods Bone marrow cells were harvested from three cynomolgus macaques and enriched for the primitive fraction by CD34 selection. CD34(+) cells were transduced with one of three retroviral vectors all expressing the GFP gene and were infused after myeloablative total body irradiation (500 cGy x 2). Following transplantation, proviral levels and fluorescence were monitored among clonogenic bone marrow progenitors and mature peripheral blood cells. Results Although 13-37% of transduced cells contained the GFP provirus and 11-13% fluoresced ex vivo, both provirus and fluorescence became almost undetectable in the peripheral blood within several months after transplantation regardless of the vectors used. However, on sampling of bone marrow at multiple time points, significant fractions (5-10%) of clonogenic progenitors contained the provirus and fluoresced exvivo reflecting a significant discrepancy between GFP gene marking levels within bone marrow cells and their mature peripheral blood progeny. The discrepancy (at least one log) persisted for more than 1 year after transplantation. Since no cytotoxic T lymphocytes against GFP were detected in the animals, an immune response against GFP is an unlikely explanation for the low levels of transduced peripheral blood cells. Administration of granulocyte colony stimulating factor and stem cell factor resulted in mobilization of transduced bone marrow cells detectable as mature granulocyte progeny which expressed the GFP gene, suggesting that transduced progenitor cells in bone marrow could be mobilized into the peripheral blood and differentiated into granulocytes. Conclusions Low levels of GFP-transduced mature cells in the peripheral blood of nonhuman primates may reflect a block to differentiation associated with GFP this block an treatment ex vivo and in vivo. Copyright (C) 2002 John Wiley Sons, Ltd.