Chemogenetic Depletion of Hypophysiotropic GnRH Neurons Does Not Affect Fertility in Mature Female Zebrafish.

The hypophysiotropic gonadotropin-releasing hormone (GnRH) and its neurons are crucial for vertebrate reproduction, primarily in regulating luteinizing hormone (LH) secretion and ovulation. However, in zebrafish, which lack GnRH1, and instead possess GnRH3 as the hypophysiotropic form, GnRH3 gene knockout did not affect reproduction. However, early-stage ablation of all GnRH3 neurons causes infertility in females, implicating GnRH3 neurons, rather than GnRH3 peptides in female reproduction. To determine the role of GnRH3 neurons in the reproduction of adult females, a Tg(gnrh3:Gal4ff; UAS:nfsb-mCherry) line was generated to facilitate a chemogenetic conditional ablation of GnRH3 neurons. Following ablation, there was a reduction of preoptic area GnRH3 neurons by an average of 85.3%, which was associated with reduced pituitary projections and gnrh3 mRNA levels. However, plasma LH levels were unaffected, and the ablated females displayed normal reproductive capacity. There was no correlation between the number of remaining GnRH3 neurons and reproductive performance. Though it is possible that the few remaining GnRH3 neurons can still induce an LH surge, our findings are consistent with the idea that GnRH and its neurons are likely dispensable for LH surge in zebrafish. Altogether, our results resurrected questions regarding the functional homology of the hypophysiotropic GnRH1 and GnRH3 in controlling ovulation.

Vasoactive Intestinal Peptide Indirectly Elicits Pituitary LH Secretion Independent of GnRH in Female Zebrafish.

Vasoactive intestinal peptide (Vip) regulates luteinizing hormone (LH) release through the direct regulation of gonadotropin-releasing hormone (GnRH) neurons at the level of the brain in female rodents. However, little is known regarding the roles of Vip in teleost reproduction. Although GnRH is critical for fertility through the regulation of LH secretion in vertebrates, the exact role of the hypophysiotropic GnRH (GnRH3) in zebrafish is unclear since GnRH3 null fish are reproductively fertile. This phenomenon raises the possibility of a redundant regulatory pathway(s) for LH secretion in zebrafish. Here, we demonstrate that VipA (homologues of mammalian Vip) both inhibits and induces LH secretion in zebrafish. Despite the observation that VipA axons may reach the pituitary proximal pars distalis including LH cells, pituitary incubation with VipA in vitro, and intraperitoneal injection of VipA, did not induce LH secretion and lhß mRNA expression in sexually mature females, respectively. On the other hand, intracerebroventricular administration of VipA augmented plasma LH levels in both wild-type and gnrh3-/- females at 1 hour posttreatment, with no observed changes in pituitary GnRH2 and GnRH3 contents and gnrh3 mRNA levels in the brains. While VipA's manner of inhibition of LH secretion has yet to be explored, the stimulation seems to occur via a different pathway than GnRH3, dopamine, and 17ß-estradiol in regulating LH secretion. The results indicate that VipA induces LH release possibly by acting with or through a non-GnRH factor(s), providing proof for the existence of functional redundancy of LH release in sexually mature female zebrafish.

Sequential actions of immune effector cells induced by viral activation of dendritic cells to eliminate murine neuroblastoma.

PURPOSE: In preclinical trails, we reported the antitumor effect of dendritic cells activated with Sendai virus (rSeV/DC) combined with γ-irradiation against neuroblastoma. However, what kind of effector cells for the combined therapy were used to show the antitumor effect was unclear. In this study, we performed radiation and rSeV/DC therapy in vivo and examined the effector cells involved. METHODS: Dendritic cells were cultured from bone marrow cells, activated with SeV and administered intratumorally at 106 weekly for 3weeks. Radiation was administered at 4Gy/time × 3 times. During the treatment, CD4+ and CD8+ cells and natural killer (NK) cells were removed by antibodies. RESULTS: Complete remission of neuroblastoma was observed in 62.5% of individuals in the combined therapy group. By depleting the effector cells using antibodies, the tumor increased in size from an early stage of treatment in the CD4+ and NK cell-depleted group. In contrast, the tumor increased in size in the late stage of treatment in the CD8+ cell-depleted group. CONCLUSION: The combination of radiation and rSeV/DC therapy induces different effector cells, depending on the time point during treatment. LEVEL OF EVIDENCE: V.

Effects of high-intensity swimming training on the bones of ovariectomized rats.

PURPOSE: This study was performed to assess the effects of high-intensity intermittent swimming training(HIT) on bone in ovariectomized rats. METHODS: Six-week-old female Sprague-Dawley rats were randomly assigned to either sham operation or bilateral ovariectomy. After surgery, they were divided into the following four groups: 1) sham-operated sedentary (S), 2) sham-operated exercise training (SE), 3) OVX sedentary (O), 4) OVX exercise training (OE) 5) OVX given 17ß-estradiol (OE2) and 6) OVX exercise training and given 17ß-estradiol (OEE). SE, OE and OEE rats were used extremely high-intensity swim exercise. The rats repeated fourteen 20-s swimming bouts with a weight equivalent to 14, 15, and 16% of body weight for the first 5, the next 9, and the last 5 days, respectively. Between exercise bouts, a 10-s pause was allowed. HIT was originally designed as an exercise method; a method that very quickly induces an increase in the maximum oxygen intake (Tabata I et al., 1996). OEE and OE2 rats were subcutaneously injected ethanol with 25µg/kg body weight 17ß-estradiol 3 times per week. RESULTS: Bone strength, bone mineral density and trabecular bone parameters were measured after a 8-weeks experimental period. Bone strength was significantly higher in the SE, OE, OE2 and OEE group compared with the O group. BV/TV was significant increase in the SE, OE groups compared with the O group. BMD showed no difference in the OE group compared with the O group. CONCLUSION: This study demonstrate some beneficial effects of postmenopausal osteoporosis of high-intensity intermittent swimming training on bone structure and strength.

Glypican 3 expression in pediatric malignant solid tumors.

PURPOSE: Glypican 3 (GPC3) is one of the cell surface heparan sulfate proteoglycans that binds to the cell membrane, and it is known as an oncofetal protein in adult malignant tumors. Clinical trials using a GPC3 peptide vaccine have already been started in Japan as a new immunotherapy for hepatocellular carcinoma in adult patients. To investigate the possibility of GPC3 immunotherapy for pediatric malignant tumors, we assessed the expression of GPC3 in pediatric malignant tumors. METHODS: Immunohistochemically, the GPC3 expression was examined in 159 pediatric solid tumors, including 35 cases of neuroblastoma, 30 cases of Wilms tumor, 10 cases of hepatoblastoma, 25 cases of germ cell tumors, 56 cases of rhabdomyosarcoma, and 3 cases of other tumors. In addition, to clarify the physiological expression during the fetal to neoinfantile period, autopsy specimens of subjects without any neoplastic diseases were assessed in 9 fetal cases and 21 neoinfantile cases. The serum levels of GPC3 were also analyzed using specimens obtained from 53 subjects by the sandwich enzyme-linked immunosorbent assay method. RESULTS: Histologically, a high rate of GPC3 expression was noted in 10 (90.9%) of the 11 subjects with yolk sac tumors and 6 (60.0%) of the 10 subjects with hepatoblastoma. In addition, 9 (30.0%) of the 30 subjects with Wilms tumors and 14 (25.0%) of the 56 subjects with rhabdomyosarcoma were positive for the expression of GPC3. Concerning autopsy specimens, most of the 23 subjects younger than 7 months showed positive findings in the liver (94.7%) and kidney (81.8%). Two subjects (100%) with yolk sac tumors and six (75.0%) of the eight subjects with hepatoblastoma serologically demonstrated a high rate of positive expression. Concerning the distribution of the serum GPC3 level according to age, 8 (80.0%) of the 10 subjects younger than 1 year showed a positive finding, while only 16 (37.3%) of the 43 subjects older than 1 year showed a positive finding. CONCLUSION: Most cases of hepatoblastoma and yolk sac tumor, and some cases of other tumors were found to express GPC3 either histologically or serologically. On the other hand, GPC3 was physiologically expressed during the fetal and neoinfantile period under 1 year of age. Although, more preliminary data and experience are required, patients older than 1 year that show a positive finding for GPC3 are considered to be appropriate candidates to receive the new immunotherapy using GPC3 peptide vaccination.

Neonatal appendicitis mimicking intestinal duplication: a case report.

INTRODUCTION: Acute appendicitis is a common disease in older children but rare in neonates. CASE PRESENTATION: We report the case of a 2-day-old Asian baby who suffered from neonatal appendicitis mimicking intestinal duplication. Laparoscopic appendectomy was successfully performed after the trans-umbilical division of adhesions, and the postoperative course was uneventful. CONCLUSION: There are few reports describing abdominal masses caused by appendicitis mimicking intestinal duplication. The laparoscopic approach for neonatal appendicitis is considered to be a safe and useful therapeutic modality with good cosmetic results.

Antagonism of VEGF by genetically engineered dendritic cells is essential to induce antitumor immunity against malignant ascites.

Malignant ascitis (MA) is a highly intractable and immunotherapy-resistant state of advanced gastrointestinal and ovarian cancers. Using a murine model of MA with CT26 colon cancer cells, we here determined that the imbalance between the VEGF-A/vascular permeability factor and its decoy receptor, soluble fms-like tryrosine kinase receptor-1 (sFLT-1), was a major cause of MA resistance to dendritic cell (DC)-based immunotherapy. We found that the ratio of VEGF-A/sFLT-1 was increased not only in murine but also in human MA, and F-gene-deleted recombinant Sendai virus (rSeV/dF)-mediated secretion of human sFLT-1 by DCs augmented not only the activity of DCs themselves, but also dramatically improved the survival of tumor-bearing animals associated with enhanced CTL activity and its infiltration to peritoneal tumors. These findings were not seen in immunodeficient mice, indicating that a VEGF-A/sFLT-1 imbalance is critical for determining the antitumor immune response by DC-vaccination therapy against MA.

The genetic and clinical significance of MYCN gain as detected by FISH in neuroblastoma.

PURPOSE: MYCN amplification (MYCN-A) is a strong prognostic factor in neuroblastoma (NB). MYCN gain which is a low level of MYCN-A as determined by FISH. It is unclear whether the MYCN gain is the pre-status of MYCN-A. This study assessed the status of MYCN gene and chromosome 2p of MYCN-A, MYCN gain and no MYCN amplification using a single nucleotide polymorphism (SNP) array, and the clinical implication of MYCN gain in NB. METHODS: The status of the MYCN gene was determined by FISH in 47 primary NB samples and the status of chromosome 2p in all cases was analyzed using an SNP array. RESULTS: 8 of the 47 cases analyzed using FISH showed MYCN-A, 7 cases showed MYCN gain and 32 cases showed no MYCN amplification. An SNP array analysis showed that only 2 of 8 cases with MYCN-A by FISH had both amplification of MYCN region and distal 2p gain and other 6 cases had amplification of the MYCN region without distal 2p gain. All 7 cases with MYCN gain by FISH had distal 2p gain without amplification of the MYCN region, and all 32 cases with no MYCN amplification by FISH demonstrated neither the amplification of the MYCN region nor the 2p gain. 5-year overall survival rate of patients with MYCN gain (n = 7, 71.4%) was not significant different from that of patients with no MYCN amplification (n = 32, 90.6%) by FISH (p = 0.11). CONCLUSIONS: These results suggested that the MYCN gain detected by FISH represents the 2p gain, and the MYCN gain is not considered to represent the pre-status of MYCN amplification.

Hedgehog signaling pathway in neuroblastoma differentiation.

PURPOSE: The hedgehog (Hh) signaling pathway is activated in some adult cancers. On the other hand, the Hh signaling pathway plays an important role in the development of the neural crest in embryos. The aim of this study is to show the activation of Hh signaling pathway in neuroblastoma (NB), a pediatric malignancy arising from neural crest cells, and to reveal the meaning of the Hh signaling pathway in NB development. METHODS: This study analyzed the expression of Sonic hedgehog (Shh), GLI1, and Patched 1 (Ptch1), transactivators of Hh signaling pathway, by immunohistochemistry in 82 NB and 10 ganglioneuroblastoma cases. All 92 cases were evaluated for the status of MYCN amplification. RESULTS: Of the 92 cases, 67 (73%) were positive for Shh, 62 cases (67%) were positive for GLI1, and 73 cases (79%) were positive for Ptch1. Only 2 (10%) of the 20 cases with MYCN amplification were positive for Shh and GLI1, and 4 cases (20%) were positive for Ptch1 (MYCN amplification vs no MYCN amplification, P ≦ .01). The percentage of GLI1-positive cells in the cases with INSS stage 1 without MYCN amplification was significantly higher than that with INSS stage 4. Of 72 cases without MYCN amplification, 60 were GLI1-positive. Twelve cases were GLI1-negative, and the prognosis of the GLI1-positive cases was significantly better than that of the GLI1-negative cases (P = .015). CONCLUSIONS: Most of NBs without MYCN amplification were positive for Shh, GLI1, and Ptch1. In the cases without MYCN amplification, the high expression of GLI1 was significantly associated with early clinical stage and a good prognosis of the patients. In contrast to adult cancers, the activation of the Hh signaling pathway in NB may be associated with the differentiation of the NB.

Concordance for neuroblastoma in monozygotic twins: case report and review of the literature.

The patients were infant male twins born by cesarean delivery following a healthy pregnancy at 36 weeks' gestation to unrelated parents. At 4 months of age, twin 2 presented with hepatomegaly and a right suprarenal mass. Resection of an adrenal tumor and a liver tumor biopsy were performed. Twin 1 had no symptoms at 4 months of age. Screening by abdominal ultrasonography showed multiple masses in the liver but no adrenal mass. Metaiodobenzylguanidine scintigraphy showed positive findings in multiple liver masses. A laparoscopic biopsy for a liver tumor was performed. All primary tumor and liver tumor specimens from twin 2 and the liver tumor of twin 1 had the same histologic classification of neuroblastoma and nearly identical genetic aberrations, including a chromosome gain or loss using array-comparative genomic hybridization. From these clinical and pathologic findings and genetic analyses, we strongly demonstrate the transplacental metastatic spread from twin 2 to twin 1. In the literature, 9 pairs of concordant twin neuroblastomas, including the current twin, have been presented; and the clinical findings of 5 twin pairs may represent placental metastases from one twin with congenital neuroblastoma to the other twin. This study is the first report presenting the possibility of twin-to-twin metastasis in monozygotic twins with neuroblastoma based on an analysis of the clinical features and genetic aberrations.

Successful treatment of advanced pancreatoblastoma by a pylorus-preserving pancreatoduodenectomy after radiation and high-dose chemotherapy.

BACKGROUND: Pancreatoblastoma (PB) is a rare malignant pancreatic tumor in children and approximately 200 cases have been reported in the literature. The overall 5-year survival rate in PB is 43-50% and no standard treatment for PB has been established. This report presents the case of a 6-year-old female with advanced PB treated successfully by a pylorus-preserving pancreatoduodenectomy (PPPD) after induction chemotherapy, radiation and stem cell transplantation (SCT). CASE REPORT: A 6-year-old girl was hospitalized for abdominal pain, fever, and vomiting. Abdominal computed tomography (CT) scan showed a 9-cm heterogeneous mass located at the pancreatic head and body, and the duodenum was completely compressed. The inferior vena cava, superior mesenteric artery, and vein were encased by the tumor. The tumor had well-defined margins and calcification. She showed severe anemia and her hemoglobin level was 4.0 g/dl, and the serum alpha-fetoprotein (AFP) level was elevated (884.8 ng/ml). Initially, a resection of the tumor was impossible. An open biopsy was performed and the histopathological diagnosis was PB. She underwent five cycles of the induction chemotherapy regimen for advanced neuroblastoma (cyclophosphamide, etoposide, vincristine, pirarubicin and cisplatin), and the tumor size was decreased to a diameter of 7.5 cm. Furthermore, chemotherapy with irinotecan and vincristine, radiotherapy (40 Gy) and SCT (etoposide, carboplatin, melphalan) was administered. The serum AFP level decreased to 41.1 ng/ml, and the tumor size was decreased to a diameter of 6.5 cm. Then she underwent a PPPD and the tumor was completely resected. The patient's recovery was uneventful, and the AFP returned to the normal values (6.2 ng/ml) after surgery. The child was administered mild postoperative chemotherapy using irinotecan and has been disease-free for 4 months and, and her serum AFP levels remain within normal values. CONCLUSION: This is the first case of PB that was treated with SCT effectively before surgery. The combined therapy including the intensive chemotherapy with SCT and the radiation followed by surgical treatment is thought to be effective for the treatment of advanced PB.

Risks and benefits of ending of mass screening for neuroblastoma at 6 months of age in Japan.

PURPOSE: The mass screening (MS) for neuroblastoma (NB) at 6 months of age in Japan was discontinued in 2004. This study assessed the risks and benefits of MS based on an analysis of NB detected before or after discontinuation of MS in Japan. METHODS: The clinical features and Brodeur's genetic type based on MYCN, DNA ploidy, and other genetic aberrations were assessed in 113 NB patients (20 cases after and 93 cases [55 MS cases] before the discontinuation of MS) older than 6 months treated at one institution since 1985. RESULTS: The 20 patients with NBs detected after MS was discontinued ranged in age from 7 to 67 months, 12 patients were stage 4, and 11 patients would have been detected at 6 months of age if they had undergone MS. The Brodeur's genetic type of these 20 patients showed that 30% (6/20) were type 1 (low risk), 55% (11/20) were type 2A (intermediate risk), and 15% (3/20) were type 2B (high risk). Of 93 patients with NB detected before MS was discontinued, 60% (56/93) were type 1, 18% (17/93) were type 2A, and 22% (20/93) were type 2B. Among the type 2A patients, 82% (9/11) of the patients detected after MS was discontinued showed stage 4, whereas only 50% (9/18) of those diagnosed before MS was discontinued were stage 4. The genetic analysis using single nucleotide polymorphism (SNP) array for type 2A showed that the pattern of genetic aberration was equivalent in those detected either before or after MS was discontinued. CONCLUSIONS: There was a decrease of type 1 and an increase of type 2A NB in patients after MS was discontinued in Japan. These results suggest that most of the type 1 detected by MS has regressed, and most of the type 2A detected by MS has appeared sporadically as advanced NB in patients older than 1 year.

Sustained and NK/CD4+ T cell-dependent efficient prevention of lung metastasis induced by dendritic cells harboring recombinant Sendai virus.

We recently demonstrated efficient antitumor immunity against murine tumors using dendritic cells (DCs) activated by recombinant Sendai viruses (rSeVs), and proposed a new concept, "immunostimulatory virotherapy," for cancer immunotherapy. However, there has been little information on the efficacy of this method in preventing metastatic diseases. In this study, we investigated the efficacy of vaccinating DCs activated by fusion gene-deleted nontransmissible rSeV (rSeV/dF) using a murine model of lung metastasis. Bolus and i.v. administration of DCs harboring rSeV/dF-expressing GFP without pulsation of tumor Ag (DC-rSeV/dF-GFP) 2 days before tumor inoculation showed efficient prevention against lung metastasis of c1300 neuroblastoma, but not of RM-9 prostatic cancer. We found that the timing of DC therapy was critical for the inhibition of pulmonary metastasis of RM-9, and that the optimal effect of DCs was seen 28 days before tumor inoculation. Interestingly, the antimetastatic effect was sustained for over 3 mo, even when administered DCs were already cleared from the lung and organs related to the immune system. Although NK cell activity had already declined to baseline at the time of tumor inoculation, Ab-mediated depletion studies revealed that CD4+ cells as well as the presence of, but not the activation of, NK cells were crucial to the prevention of lung metastasis. These results are the first demonstration of efficient inhibition of lung metastasis via bolus administration of virally activated DCs that was sustained and NK/CD4+ cell-dependent, and may suggest a potentially new mechanism of DC-based immunotherapy for advanced malignancies.

Efficient protective immunity against Trypanosoma cruzi infection after nasal vaccination with recombinant Sendai virus vector expressing amastigote surface protein-2.

Chagas' disease, caused by infection with the protozoan parasite Trypanosoma cruzi (T. cruzi), is intractable showing a high mortality rate, and the development of effective vaccines is much desired. To examine the efficacy of a new mode of recombinant viral vaccine, we constructed two non-transmissible Sendai viruses (rSeV/dF) encoding the full-length parasite antigen amastigote surface protein-2 (ASP2) or ASP2 fused with a mono-ubiquitin on its N-terminus (UASP2). C57BL/6 mice immunized intranasally with rSeV/dF expressing either ASP2 or UASP2 showed significantly suppressed parasitemia and could be protected from lethal T. cruzi challenge. Depletion of CD8(+) T cells around the time of infection with T. cruzi completely abolished this protection, confirming that acquired immunity against the infection of T. cruzi is dependent on CD8(+) T cells. We also demonstrated that the protective immunity correlated with higher secretion of interferon-gamma (IFN-gamma) by spleen cells on in vitro-specific or non-specific stimulation. Increased CTL activity was also confirmed by degranulation or CTL assays. Interestingly, the control virus, rSeV/dF-GFP, induced even a higher IFN-gamma production from spleen cells following non-specific but not specific stimulation in vitro, suggesting that SeV may also be a good adjuvant when used as a vaccine vehicle. Taking together, the current findings indicate that recombinant Sendai virus expressing the ASP2 or UASP2 antigens of T. cruzi are interesting candidates for the development of a new mode of recombinant viral vaccine against Chagas' disease.

Clinical implications of a slight increase in the gene dosage of MYCN in neuroblastoma determined using quantitative PCR.

INTRODUCTION: Recently, determining the MYCN status in neuroblastoma (NB) using the quantitative PCR (Q-PCR) and FISH instead of the Southern blotting (SB) has been recommended. In order to assess the implications of the gene dosage of MYCN in NB, the MYCN status was evaluated using Q-PCR on DNA extracted from small areas of NB specimens obtained using laser capture microdissection (LCM). MATERIALS AND METHODS: MYCN gene dosages (MYCN/NAGK) were determined in 63 primary NB block samples, as well as in 243 microdissected tissues from 63 samples using Q-PCR. In 23 of 63 cases, the MYCN gene status was evaluated using FISH. RESULTS: Nine block samples with the amplification of MYCN based on SB showed a remarkable increase of the MYCN gene dosage using Q-PCR. Twelve of 54 block samples with no amplification of MYCN based on SB showed a slight increase of the MYCN gene dosage (3.56 > or == MYCN/NAGK > 1.84), and 8 of these 12 cases were in the advanced stage. Among these 12 cases, 1 case had several LCM areas with a high copy number of MYCN and several LCM areas which showed no increase of MYCN gene. Another case showed a slight increase in the MYCN gene dosage (3.65 < or == MYCN/NAGK < or == 4.82) in all LCM areas. In addition, a large number of cells with the MYCN gain were found using FISH in the block sample. In 2 other cases of 12 cases, although no LCM areas showed an increased gene dosage of MYCN, a small number of cells with MYCN amplification were found using FISH were found in the block sample. CONCLUSION: A slight increase in the gene dosage of MYCN detected by Q-PCR may indicate that the NB tissue contains a small number of cells with the MYCN amplification or a large number of cells with the MYCN gain, which are associated with the aggressive progression of NB.

Newly-developed Sendai virus vector for retinal gene transfer: reduction of innate immune response via deletion of all envelope-related genes.

BACKGROUND: Recombinant Sendai virus vectors (rSeV) constitute a new class of cytoplasmic RNA vectors that have shown efficient gene transfer in various organs, including retinal tissue; however, the related immune responses remain to be overcome in view of clinical applications. We recently developed a novel rSeV from which all envelope-related genes were deleted (rSeV/dFdMdHN) and, in the present study, assess host immune responses following retinal gene transfer. METHODS: rSeV/dFdMdHN or conventional F-gene deleted rSeV (rSeV/dF) was injected into subretinal space of adult Wistar rats or C57BL/6 mice. The transgene expression and histopathological findings were assessed at various time points. Immunological assessments, including the expression of proinflammatory cytokines, natural killer (NK)-cell activity, as well as SeV-specific cytotoxic T lymphocytes (CTLs) and antibodies, were performed following vector injection. RESULTS: rSeV/dFdMdHN showed high gene transfer efficiency into the retinal pigment epithelium at an equivalent level to that seen with rSeV/dF. In the early phase, the upregulation of proinflammatory cytokines, local inflammatory cell infiltration and tissue damage that were all prominently seen in rSeV/dF injection were dramatically diminished using rSeV/dFdMdHN. NK cell activity was also decreased, indicating a reduction of the innate immune response. In the later phase, on the other hand, CTL activity and anti-SeV antibodies were similarly induced, even using rSeV/dFdMdHN, and resulted in transient transgene expression in both vector types. CONCLUSIONS: Deletion of envelope-related genes of rSeV dramatically reduces the vector-induced retinal damage and may extend the utility for ocular gene transfer; however, further studies regulating the acquired immune response are required to achieve long-term transgene expression of rSeV.

In vivo repopulation of cytoplasmically gene transferred hematopoietic cells by temperature-sensitive mutant of recombinant Sendai viral vector.

Recent clinical studies revealed 'proof of concept' of gene therapy targeting hematopoietic stem cells (HSCs) to treat hematopoietic disorders. However, vector integration-related adverse events of retroviral vectors have slowed progress in this field. As an initial step to overcoming this hurdle, we examined the potential of an improved cytoplasmic RNA vector, temperature-sensitive mutant non-transmissible recombinant Sendai virus (ts-rSeV/dF), for gene transfer to murine HSCs and progenitors. Both conventional vector and ts-rSeV/dF-GFP showed efficient gene transfer to T-lymphocyte-depleted syngeneic bone marrow cells (BMCs) (>85%), but only BMCs treated with ts-rSeV/dF-GFP but not with conventional vector efficiently repopulated in the recipient mice, associated with multilineage differentiation in vitro and in vivo. To our knowledge, this is the first demonstration of the in vivo reconstruction of hematopoietic series by cytoplasmically gene transferred BMCs, that warrants further investigation to realize this strategy in clinical settings.