Tokunori Ikeda

Characterization of dendritic cells and macrophages generated by directed differentiation from mouse induced pluripotent stem cells.

Methods have been established to generate dendritic cells (DCs) from mouse and human embryonic stem (ES) cells. We designated them as ES‐DCs and mouse models have demonstrated the induction of anti‐cancer immunity and prevention of autoimmune disease by in vivo administration of genetically engineered ES‐DCs. For the future clinical application of ES‐DCs, the histoincompatibility between patients to be treated and available human ES cells and the ethical concerns associated with human ES cells may be serious obstacles. However, recently developed induced pluripotent stem (iPS) cell technology is expected to resolve these issues. This report describes the generation and characterization of DCs derived from mouse iPS cells. The iPS cell‐derived DCs (iPS‐DCs) possessed the characteristics of DCs including the capacity of T‐cell‐stimulation, antigen‐processing and presentation and cytokine production. DNA microarray analyses revealed the upregulation of genes related to antigen‐presenting functions during differentiation into iPS‐DCs and similarity in gene expression profile in iPS‐DCs and bone marrow cell‐derived DCs. Genetically modified iPS‐DCs expressing antigenic protein primed T‐cells specific to the antigen in vivo and elicited efficient antigen‐specific anti‐tumor immunity. In addition, macrophages were generated from iPS cells (iPS‐MP). iPS‐MP were comparable with bone marrow cell‐derived macrophages in the cell surface phenotype, functions, and gene expression profiles. Stem Cells 2009;27:1021–1031

Generation of dendritic cells and macrophages from human induced pluripotent stem cells aiming at cell therapy

This report describes generation of dendritic cells (DCs) and macrophages from human induced pluripotent stem (iPS) cells. iPS cell-derived DC (iPS-DC) exhibited the morphology of typical DC and function of T-cell stimulation and antigen presentation. iPS-DC loaded with cytomegalovirus (CMV) peptide induced vigorous expansion of CMV-specific autologous CD8+ T cells. Macrophages (iPS-MP) with activity of zymosan phagocytosis and C5a-induced chemotaxis were also generated from iPS cells. Genetically modified iPS-MPs were generated by the introduction of expression vectors into undifferentiated iPS cells, isolation of transfectant iPS cell clone and subsequent differentiation. By this procedure, we generated iPS-MP expressing a membrane-bound form of single chain antibody (scFv) specific to amyloid β (Aβ), the causal protein of Alzheimer’s disease. The scFv-transfectant iPS-MP exhibited efficient Aβ-specific phagocytosis activity. iPS-MP expressing CD20-specific scFv engulfed and killed BALL-1 B-cell leukemia cells. Anti-BALL-1 effect of iPS-MP in vivo was demonstrated in a xeno-transplantation model using severe combined immunodeficient mice. In addition, we established a xeno-free culture protocol to generate iPS-DC and iPS-MP. Collectively, we demonstrated the possibility of application of iPS-DC and macrophages to cell therapy.

Neuroradiologic and clinicopathologic features of oculoleptomeningeal type amyloidosis

Objective: To clarify the pathogenesis of leptomeningeal amyloidosis in familial amyloidotic polyneuropathy amyloidogenic transthyretin Y114C (FAP ATTR Y114C). Methods: The authors analyzed eight FAP ATTR Y114C patients. Six patients showed CNS symptoms associated with leptomeningeal amyloidosis. To examine the function of the blood–CSF barrier and blood–brain barrier (BBB), the authors performed CSF and MRI studies. The authors also performed a histopathologic study of autopsy specimens to examine the distribution of amyloid deposition in the CNS. Results: CSF study showed high total protein concentrations and increased albumin CSF/serum concentration quotients (Qalb; an indication of blood–CSF barrier function). MRI with gadolinium (Gd) revealed enhancement from brainstem to spinal cord. Serial brain MRI studies with FLAIR images after Gd administration showed Gd leakage into the subarachnoid space (two patients). These findings suggested the blood–CSF barrier and BBB dysfunctions. Constructive interference in steady state (CISS) three-dimensional Fourier transformation (CISS-3DFT) sequence analysis demonstrated amyloid-induced funiculus structures joining the spinal cord and dura mater (one patient). Histopathologic study revealed intense amyloid deposition in leptomeninges, vessel walls, and parenchyma in spinal cord and the brain. These distributions of amyloid deposition are unique compared to other TTR related leptomeningeal amyloidosis. Conclusions: Patients with familial amyloidotic polyneuropathy amyloidogenic transthyretin Y114C had CNS disorders related to amyloid deposition in leptomeninges, vessel walls, and parenchyma in spinal cord and the brain. The pathogenesis of CNS disorders may reflect disruption of the blood–CSF barrier and blood–brain barrier by amyloid deposition.

TAP-deficient human iPS cell-derived myeloid cell lines as unlimited cell source for dendritic cell-like antigen-presenting cells

We previously reported a method to generate dendritic cell (DC)-like antigen-presenting cells (APC) from human induced pluripotent stem (iPS) cells. However, the method is relatively complicated and laborious. In the current study, we attempted to establish a method through which we could obtain a large number of functional APC with a simple procedure. We transduced iPS cell-derived CD11b+ myeloid cells with genes associated with proliferative or anti-senescence effects, enabling the cells to propagate for more than 4 months in a macrophage colony-stimulating factor (M-CSF)-dependent manner while retaining their capacity to differentiate into functional APC. We named these iPS cell-derived proliferating myeloid cells ‘iPS-ML’, and the iPS-ML-derived APC ‘ML-DC’. In addition, we generated TAP2-deficient iPS cell clones by zinc finger nuclease-aided targeted gene disruption. TAP2-deficient iPS cells and iPS-ML avoided recognition by pre-activated allo-reactive CD8+ T cells. TAP2-deficient ML-DC expressing exogenously introduced HLA-A2 genes stimulated HLA-A2-restricted MART-1-specific CD8+ T cells obtained from HLA-A2-positive allogeneic donors, resulting in generation of MART-1-specific cytotoxic T lymphocyte (CTL) lines. TAP-deficient iPS-ML introduced with various HLA class I genes may serve as an unlimited source of APC for vaccination therapy. If administered into allogeneic patients, ML-DC with appropriate genetic modifications may survive long enough to stimulate antigen-specific CTL and, after that, be completely eliminated. Based on the present study, we propose an APC-producing system that is simple, safe and applicable to all patients irrespective of their HLA types.

Dual Effects of TRAIL in Suppression of Autoimmunity: The Inhibition of Th1 Cells and the Promotion of Regulatory T Cells

TRAIL is known to play a pivotal role in the inhibition of autoimmune disease. We previously demonstrated that administration of dendritic cells engineered to express TRAIL and myelin-oligodendrocyte glycoprotein reduced the severity of experimental autoimmune encephalomyelitis and suggested that CD4+CD25+ regulatory T cells (Tregs) were involved in mediating this preventive effect. In the current study, we investigated the effect of TRAIL on Tregs, as well as conventional T cells, using TRAIL-deficient mice. Upon induction of experimental autoimmune encephalomyelitis, TRAIL-deficient mice showed more severe clinical symptoms, a greater frequency of IFN-γ–producing CD4+ T (Th1) cells, and a lower frequency of CD4+Foxp3+ Tregs than did wild-type mice. In vitro, conventional T cells stimulated by bone marrow-derived dendritic cells (BM-DCs) from TRAIL-deficient mice showed a greater magnitude of proliferation than did those stimulated by BM-DCs from wild-type mice. In contrast, TRAIL expressed on the stimulator BM-DCs enhanced the proliferative response of CD4+CD25+ Tregs in the culture. The functional TRAILR, mouse death receptor 5 (mDR5), was expressed in conventional T cells and Tregs upon stimulation. In contrast, the decoy receptor, mDc-TRAILR1, was slightly expressed only on CD4+CD25+ Tregs. Therefore, the distinct effects of TRAIL may be due to differences in the mDc-TRAILR1 expression or the signaling pathways downstream of mouse death receptor 5 between the two T cell subsets. Our data suggest that TRAIL suppresses autoimmunity by two mechanisms: the inhibition of Th1 cells and the promotion of Tregs.

Derlin-1 overexpression ameliorates mutant SOD1-induced endoplasmic reticulum stress by reducing mutant SOD1 accumulation

Unfolded protein responses, including induction of stress sensor kinases, chaperones, and apoptotic mediators, are involved in the familial amyotrophic lateral sclerosis (ALS) model related to mutant Cu/Zn superoxide dismutase (SOD1) and sporadic ALS. We hypothesized that the endoplasmic reticulum-resident factor Derlin-1 plays a pivotal role in the regulation of misfolded proteins evoked by mutant SOD1. We show that Derlin-1 overexpression reduced mutant SOD1-induced cell toxicity and increased cell viability by suppressing the activation of the ER stress pathway factors: immunoglobulin-binding protein, activating transcription factor 6 p50, and C/EBP homologous protein. Interestingly, exogenous Derlin-1 resulted in a decrease in the amount of mutant SOD1, and a lesser decrease in that of wild-type SOD1, in transfected cells. Reduced SOD1 protein expression was observed in the microsomal fraction of wild-type and mutant SOD1 cells. Our results indicate that Derlin-1 regulates the turn over of SOD1 by promoting the proteasomal and autophagosomal degradation of SOD1 protein, but not by decreasing mutant SOD1 mRNA levels. Insights into the effects of Derlin-1 on mutant SOD1 may facilitate advancements in the treatment of motor neuron degeneration associated with ALS.

Multiple Antigen-targeted Immunotherapy With α-Galactosylceramide–loaded and Genetically Engineered Dendritic Cells Derived From Embryonic Stem Cells

Numerous tumor-associated antigens (TAA) have been identified and their use in immunotherapy is considered to be promising. For TAA-based immunotherapy to be broadly applied as standard anticancer medicine, methods for active immunization should be improved. In the present study, we demonstrated the efficacy of multiple TAA-targeted dendritic cell (DC) vaccines and also the additive effects of loading α-galactosylceramide to DC using mouse melanoma models. On the basis of previously established methods to generate DC from mouse embryonic stem cells (ES-DC), 4 kinds of genetically modified ES-DC, which expressed the melanoma-associated antigens, glypican-3, secreted protein acidic and rich in cysteine, tyrosinase-related protein-2, or gp100 were generated. Anticancer effects elicited by immunization with the ES-DC were assessed in preventive and also therapeutic settings in the models of peritoneal dissemination and spontaneous metastasis to lymph node and lung. The in vivo transfer of a mixture of 3 kinds of TAA-expressing ES-DC protected the recipient mice from melanoma cells more effectively than the transfer of ES-DC expressing single TAA, thus demonstrating the advantage of multiple as compared with single TAA-targeted immunotherapy. Loading ES-DC with α-galactosylceramide further enhanced the anticancer effects, suggesting that excellent synergic effects of TAA-specific cytotoxic T lymphocytes and natural killer T cells against metastatic melanoma can be achieved by using genetically modified ES-DC. With the aid of advancing technologies related to pluripotent stem cells, induced pluripotent stem cells, and ES cells, clinical application of DC highly potent in eliciting anticancer immunity will be realized in the near future.

Activation of Antigen-Specific Cytotoxic T Lymphocytes by β2-Microglobulin or TAP1 Gene Disruption and the Introduction of Recipient-Matched MHC Class I Gene in Allogeneic Embryonic Stem Cell-Derived Dendritic Cells

A method for the genetic modification of dendritic cells (DC) was previously established based on the in vitro differentiation of embryonic stem (ES) cells to DC (ES-DC). The unavailability of human ES cells genetically identical to the patients will be a problem in the future clinical application of this technology. This study attempted to establish a strategy to overcome this issue. The TAP1 or β2-microglobulin (β2m) gene was disrupted in 129 (H-2b)-derived ES cells and then expression vectors for the H-2Kd or β2m-linked form of Kd (β2m-Kd) were introduced, thus resulting in two types of genetically engineered ES-DC, TAP1−/−/Kd ES-DC and β2m−/−/β2m-Kd ES-DC. As intended, both of the transfectant ES-DC expressed Kd but not the intrinsic H-2b haplotype-derived MHC class I. β2m−/−/β2m-Kd and TAP1−/−/Kd ES-DC were not recognized by pre-activated H-2b-reactive CTL and did not prime H-2b reactive CTL in vitro or in vivo. β2m−/−/β2m-Kd ES-DC and TAP1−/−/Kd ES-DC had a survival advantage in comparison to β2m+/−/β2m-Kd ES-DC and TAP1+/+/Kd ES-DC, when transferred into BALB/c mice. Kd-restricted RSV-M2-derived peptide-loaded ES-DC could prime the epitope-specific CTL upon injection into the BALB/c mice, irrespective of the cell surface expression of intrinsic H-2b haplotype-encoded MHC class I. β2m−/−/β2m-Kd ES-DC were significantly more efficient in eliciting immunity against RSV M2 protein-expressing tumor cells than β2m+/−/β2m-Kd ES-DC. The modification of the β2m or TAP gene may therefore be an effective strategy to resolve the problem of HLA class I allele mismatch between human ES or induced pluripotent stem cells and the recipients to be treated.

Therapeutic Effect of Human iPS-Cell-Derived Myeloid Cells Expressing IFN-β against Peritoneally Disseminated Cancer in Xenograft Models

We recently developed a method to generate myeloid cells with proliferation capacity from human iPS cells. iPS-ML (iPS-cell–derived myeloid/macrophage line), generated by introducing proliferation and anti-senescence factors into iPS-cell–derived myeloid cells, grew continuously in an M-CSF–dependent manner. A large number of cells exhibiting macrophage-like properties can be readily obtained by using this technology. In the current study, we evaluated the possible application of iPS-ML in anti-cancer therapy. We established a model of peritoneally disseminated gastric cancer by intraperitoneally injecting NUGC-4 human gastric cancer cells into SCID mice. When iPS-ML were injected intraperitoneally into the mice with pre-established peritoneal NUGC-4 tumors, iPS-ML massively accumulated and infiltrated into the tumor tissues. iPS-ML expressing IFN-β (iPS-ML/IFN-β) significantly inhibited the intra-peritoneal growth of NUGC-4 cancer. Furthermore, iPS-ML/IFN-β also inhibited the growth of human pancreatic cancer MIAPaCa-2 in a similar model. iPS-ML are therefore a promising treatment agent for peritoneally disseminated cancers, for which no standard treatment is currently available.

A reversible lesion of the corpus callosum splenium with adult influenza-associated encephalitis/encephalopathy: a case report.

ABstractIntroductionInfluenza virus-associated encephalitis/encephalopathy is a severe childhood illness with a poor prognosis. Adult case reports are rare and, to date, there have been no reports of adults with a mild subcortical encephalopathy with reversible lesions of the corpus callosum splenium.Case presentationA previously healthy 35-year-old man presented with acute progressive tetraplegia, transcortical motor aphasia and a mild decrease in his consciousness during his recovery after receiving oseltamivir phosphate treatment, and influenza type A antiviral medication. The initial magnetic resonance imaging study at day 1 showed symmetrical diffuse lesions in the white matter and a lesion on the central portion of the corpus callosum splenium. These findings had resolved on follow-up studies at day 8 and day 146. His neurological deficits mostly recovered within 12 hours following methylprednisolone pulse therapy. The levels of interleukin-6 and interleukin-10 in his blood and cerebrospinal fluid were initially elevated, but rapidly decreased to normal levels by day 8.ConclusionIt is important for clinicians to recognize that even in adulthood, the subcortical encephalopathy observed during the therapeutic treatment for influenza type A infection can occur in conjunction with a reversible lesion of the corpus callosum, which may recover quickly. In addition, the cytokine storm in the blood system and the corticospinal cavity may play an important role in the etiology of the disease process.