Human artificial chromosome carrying R-spondin1 and IL-22 expression cassettes in rejuvenated MSCs enhances therapeutic efficacy in ulcerative colitis model mice.

Ulcerative colitis (UC) is an incurable intestinal disease, with current treatments mainly focused on inflammation control and, in severe cases, surgical resection. Recent studies have highlighted the need for new therapies that promote tissue regeneration. R-spondin-1 (RSPO1) and interleukin-22 (IL-22) have shown anti-inflammatory and regenerative effects in UC models, but have short half-lives and poor targeting abilities.

Pathological Comparison of TDP-43 Between Motor Neurons and Interneurons Expressed by a Tetracycline Repressor System on the Mouse Artificial Chromosome.

Background: Cytoplasmic mislocalization of TAR-DNA binding protein of 43 kDa (TDP-43) is a major hallmark of amyotrophic lateral sclerosis (ALS). TDP-43 aggregation is detected in the cortical and spinal motor neurons in most ALS cases; however, pathological mechanism of this mislocalized TDP-43 remains unknown.

Methods: We generated a tetracycline-inducible TDP-43 A315T system on a mouse artificial chromosome (MAC) vector to avoid transgene-insertional mutagenesis, established a mouse embryonic stem (ES) cell line holding this MAC vector system, and investigated whether overexpressed exogenous TDP-43 A315T was mislocalized in the cytoplasm of the ES cell-derived neurons and triggered the neurotoxic effects on these cells.

A transchromosomic rat model with human chromosome 21 shows robust Down syndrome features.

Progress in earlier detection and clinical management has increased life expectancy and quality of life in people with Down syndrome (DS). However, no drug has been approved to help individuals with DS live independently and fully. Although rat models could support more robust physiological, behavioral, and toxicology analysis than mouse models during preclinical validation, no DS rat model is available as a result of technical challenges.

Engineering of human induced pluripotent stem cells via human artificial chromosome vectors for cell therapy and disease modeling.

Genetic engineering of induced pluripotent stem cells (iPSCs) holds great promise for gene and cell therapy as well as drug discovery. However, there are potential concerns regarding the safety and control of gene expression using conventional vectors such as viruses and plasmids. Although human artificial chromosome (HAC) vectors have several advantages as a gene delivery vector, including stable episomal maintenance and the ability to carry large gene inserts, the full potential of HAC transfer into iPSCs still needs to be explored.

Development of a Safeguard System Using an Episomal Mammalian Artificial Chromosome for Gene and Cell Therapy.

The development of a safeguard system to remove tumorigenic cells would allow safer clinical applications of stem cells for the treatment of patients with an intractable disease including genetic disorders. Such safeguard systems should not disrupt the host genome and should have long-term stability. Here, we attempted to develop a tumor-suppressing mammalian artificial chromosome containing a safeguard system that uses the immune rejection system against allogeneic tissue from the host.

Retargeting of microcell fusion towards recipient cell-oriented transfer of human artificial chromosome.

Background: Human artificial chromosome (HAC) vectors have some unique characteristics as compared with conventional vectors, carrying large transgenes without size limitation, showing persistent expression of transgenes, and existing independently from host genome in cells. With these features, HACs are expected to be promising vectors for modifications of a variety of cell types. However, the method of introduction of HACs into target cells is confined to microcell-mediated chromosome transfer (MMCT), which is less efficient than other methods of vector introduction.

The transfer of human artificial chromosomes via cryopreserved microcells.

Microcell-mediated chromosome transfer (MMCT) technology enables a single and intact mammalian chromosome or megabase-sized chromosome fragments to be transferred from donor to recipient cells. The conventional MMCT method is performed immediately after the purification of microcells. The timing of the isolation of microcells and the preparation of recipient cells is very important.

Prognostic significance of sirtuin 2 protein nuclear localization in glioma: an immunohistochemical study.

The sirtuin 2 (SIRT2) protein is a member of the sirtuin family and homologous to Sir2 (silent information regulator 2) of Saccharomyces cerevisiae. To assess the pathobiological significance of SIRT2 protein expression and/or subcellular localization in human glioma, we examined SIRT2 protein expression in human gliomas using a polyclonal anti-SIRT2 antibody and immunohistochemistry. In this study, samples from 23 patients with glioblastoma (GB, grade IV), 8 patients with diffuse astrocytoma (DA, grade II) and 5 healthy individuals were examined.

A new chromosome 14-based human artificial chromosome (HAC) vector system for efficient transgene expression in human primary cells.

The use of non-integrating human artificial chromosomes (HACs) in gene therapy possibly allows for safe and reliable genetic modification of human cells without insertional mutagenesis and/or unexpected oncogene activations. Although we previously demonstrated that the HAC provides long-term therapeutic erythropoietin (EPO) production in normal human primary fibroblasts (hPFs), the expression level of EPO was too low to provide medical benefits for human therapy. Thus, the next challenge for the application of this system in therapeutic purposes is to improve the transgene expression on HACs.

Integration-free iPS cells engineered using human artificial chromosome vectors.

Human artificial chromosomes (HACs) have unique characteristics as gene-delivery vectors, including episomal transmission and transfer of multiple, large transgenes. Here, we demonstrate the advantages of HAC vectors for reprogramming mouse embryonic fibroblasts (MEFs) into induced pluripotent stem (iPS) cells. Two HAC vectors (iHAC1 and iHAC2) were constructed.

Integration-free and stable expression of FVIII using a human artificial chromosome.

Human artificial chromosome (HAC) has several advantages as a gene therapy vector, including stable episomal maintenance that avoids insertional mutations and the ability to carry large gene inserts. To examine the copy number effect on the gene expression levels and its stability for a long-term culture for a future application in gene therapy, we constructed a HAC vector carrying the human factor VIII (FVIII) complementary DNA, FVIII-HAC in Chinese hamster ovary (CHO) cells. One and more copies of FVIII gene on the HAC were expressed in the copy-number-dependent manner in the CHO cells.

Complete genetic correction of ips cells from Duchenne muscular dystrophy.

Human artificial chromosome (HAC) has several advantages as a gene therapy vector, including stable episomal maintenance that avoids insertional mutations and the ability to carry large gene inserts including the regulatory elements. Induced pluripotent stem (iPS) cells have great potential for gene therapy, as such cells can be generated from the individual's own tissues, and when reintroduced can contribute to the specialized function of any tissue. As a proof of concept, we show herein the complete correction of a genetic deficiency in iPS cells derived from Duchenne muscular dystrophy (DMD) model (mdx) mice and a human DMD patient using a HAC with a complete genomic dystrophin sequence (DYS-HAC).

A gene delivery system with a human artificial chromosome vector based on migration of mesenchymal stem cells towards human glioblastoma HTB14 cells.

Mesenchymal stem cells (MSCs) have been expected to become useful gene delivery vehicles against human malignant gliomas when coupled with an appropriate vector system, because they migrate towards the lesion. Human artificial chromosomes (HACs) are non-integrating vectors with several advantages for gene therapy, namely, no limitations on the size and number of genes that can be inserted. We investigated the migration of human immortalized MSCs bearing a HAC vector containing the herpes simplex virus thymidine kinase gene (HAC-tk-hiMSCs) towards malignant gliomas in vivo.

SIRT2 downregulation confers resistance to microtubule inhibitors by prolonging chronic mitotic arrest.

We previously identified SIRT2, a deacetylase for tubulin and histone H4, as a protein downregulated in gliomas, and reported that exogenously-expressed SIRT2 arrests the cell cycle prior to entry into mitosis to prevent chromosomal instability in response to microtubule inhibitors (MTIs) such as nocodazole, characteristics previously reported for the CHFR protein. We herein investigated the effects of SIRT2 downregulation on sensitivity to MTIs using HCT116 cells, a mitotic checkpoint-proficient near-diploid cancer cell line used for studying checkpoints. We found that SIRT2 downregulation confers resistance to MTIs as well as that of BubR1, a well-characterized mitotic checkpoint protein, though by a different mechanism.

Telomerase-mediated life-span extension of human primary fibroblasts by human artificial chromosome (HAC) vector.

Telomerase-mediated life-span extension enables the expansion of normal cells without malignant transformation, and thus has been thought to be useful in cell therapies. Currently, integrating vectors including the retrovirus are used for human telomerase reverse transcriptase (hTERT)-mediated expansion of normal cells; however, the use of these vectors potentially causes unexpected insertional mutagenesis and/or activation of oncogenes. Here, we established normal human fibroblast (hPF) clones retaining non-integrating human artificial chromosome (HAC) vectors harboring the hTERT expression cassette.

The molecular biology of mammalian SIRT proteins: SIRT2 in cell cycle regulation.

Sir2, an NAD+-dependent protein deacetylase, extends the lifespan in diverse species from yeast to flies. Mammals have seven homologs of Sir2, SIRT1-7, which affect aging and metabolism and which are potential targets for pharmacologic intervention. We identified SIRT2, which preferentially deacetylates tubulin and histone H4, as a downregulated protein in gliomas due to its epigenetic aberration.

A comparison study in the proteomic signatures of multipotent germline stem cells, embryonic stem cells, and germline stem cells.

Germline stem (GS) cells can only differentiate into germline cells, while multipotent germ stem (mGS) cells, like embryonic stem (ES) cells, can differentiate into various somatic cells and tissues. The proteomic profiles in GS and mGS cells were compared by two-dimensional gel electrophoresis. Ten down-regulated and 16 up-regulated proteins were differentially expressed in mGS cells in comparison to GS cells, and these proteomic characteristics were very much similar to those in ES cells indicating that multipotency of mGS and ES cells is based on a common molecular event(s).

Heat-regulated production and secretion of insulin from a human artificial chromosome vector.

Human artificial chromosomes (HACs) behave as independent minichromosomes and are potentially useful as a way to achieve safe, long-term expression of a transgene. In this study, we sought to elucidate the potential of HAC vectors carrying the human proinsulin transgene for gene therapy of insulin-dependent diabetes mellitus (IDDM) using non-beta-cells as a host for the vector. To facilitate the production of mature insulin in non-beta-cells and to safely regulate the level of transgene expression, we introduced furin-cleavable sites into the proinsulin coding region and utilized the heat shock protein 70 (Hsp70) promoter.

Proteomic identification of differentially-expressed genes in human gastric carcinomas.

Although genetic alterations in proto-oncogenes, tumor-suppressor genes, cell cycle regulators, and cell growth factors have been implicated in the process of human gastric carcinogenesis, the principle carcinogenic mechanisms are not fully understood. In this study, we used a proteomic approach to search for genes that may be involved in gastric carcinogenesis and that might serve as diagnostic markers. We identified nine proteins with increased expression and 13 proteins with decreased expression in gastric carcinomas.

Abnormal accumulation of citrullinated proteins catalyzed by peptidylarginine deiminase in hippocampal extracts from patients with Alzheimer's disease.

Citrullinated proteins are the products of a posttranslational process in which arginine residues undergo modification into citrulline residues when catalyzed by peptidylarginine deiminases (PADs) in a calcium ion-dependent manner. In our previous report, PAD2 expressed mainly in the rat cerebrum became activated early in the neurodegenerative process. To elucidate the involvement of protein citrullination in human neuronal degeneration, we examined whether citrullinated proteins are produced during Alzheimer's disease (AD).

Searching for genes involved in arteriosclerosis: proteomic analysis of cultured human umbilical vein endothelial cells undergoing replicative senescence.

It is known that replicative senescence of endothelium in vivo contributes at least partially to age-related vascular disorders such as arteriosclerosis. However, the genes involved in this process remain to be identified. In this study, we employed a proteomics-based approach to identify candidate genes using in vitro cultured human umbilical vein endothelial cells (HUVECs) as an experimental model for replicative senescence.

Proteomics-based identification of differentially expressed genes in human gliomas: down-regulation of SIRT2 gene.

A number of chromosomal abnormalities including 19q deletions have been associated with the formation of human gliomas. In this study, we employed a proteomics-based approach to identify possible genes involved in glioma tumorigenesis which may serve as potential diagnostic molecular markers for this type of cancer. By comparing protein spots from gliomas and non-tumor tissues using two-dimensional (2D) gel electrophoresis, we identified 11 up-regulated proteins and four down-regulated proteins in gliomas.

Use of real-time RT-PCR for the detection of allelic expression of an imprinted gene.

Measurement of the relative amounts of transcripts from two alleles is important in the study of imprinted genes, since quantitative differences that vary among tissues or individuals, and subtle differences in the ratio of allelic expression can have pathobiological significance. Discrimination of alleles is commonly based on PCR, followed by restriction endonuclease digestion to recognize a polymorphic site. However, the use of restriction enzymes misses most of the available single nucleotide polymorphisms.