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Background: Although numerous reports addressing pathological involvements of diabetic polyneuropathy have been conducted, a universally effective treatment of diabetic polyneuropathy has not yet been established. Recently, regenerative medicine studies in diabetic polyneuropathy using somatic stem/progenitor cell have been reported. However, the effectiveness of these cell transplantations was restricted because of their functional and numerical impairment in diabetic objects. Here, we investigated the efficacy of treatment for diabetic polyneuropathy using angioblast-like cells derived from mouse embryonic stem cells., Methods and Results: Angioblast-like cells were obtained from mouse embryonic stem cells and transplantation of these cells improved several physiological impairments in diabetic polyneuropathy: hypoalgesia, delayed nerve conduction velocities, and reduced blood flow in sciatic nerve and plantar skin. Furthermore, pathologically, the capillary number to muscle fiber ratios were increased in skeletal muscles of transplanted hindlimbs, and intraepidermal nerve fiber densities were ameliorated in transplanted plantar skin. Transplanted cells maintained their viabilities and differentiated to endothelial cells and smooth muscle cells around the injection sites. Moreover, several transplanted cells constructed chimeric blood vessels with recipient cells., Conclusions: These results suggest that transplantation of angioblast like cells induced from embryonic stem cells appears to be a novel therapeutic strategy for diabetic polyneuropathy.

Chronic obstructive pulmonary disease (COPD) is characterized by lung destruction and inflammation. As a major compound of cigarette smoke, acrolein plays a critical role in the induction of respiratory diseases. GADD34 is known as a growth arrest and DNA damage-related gene, which can be overexpressed in adverse environmental conditions. Here we investigated the effects of GADD34 on acrolein-induced lung injury. The intranasal exposure of acrolein induced the expression of GADD34, developing the pulmonary damage with inflammation and increase of reactive oxygen species (ROS). Conversely, the integrality of pulmonary structure was preserved and the generation of ROS was reduced in GADD34-knockout mice. Acrolein-induced phosphorylation of eIF2α in GADD34-knockout epithelial cells by shRNA protected cell death by reducing misfolded protein-caused oxidative stress. These data indicate that GADD34 participates in the development of acrolein-induced lung injury.

Hematopoietic stem cells (HSCs) generate all known hematopoietic lineages and are capable of self-renewal. Upon aging, myeloid-biased HSCs are maintained, whereas lymphoid-biased HSCs are lost. GADD34 protein is expressed in myeloid-lineage cells and has been cloned from them. However, the function of GADD34 in the myeloid lineage has not yet been elucidated. Here, we show that early age-dependent deviation to the myeloid lineage occurs in GADD34-deficient mice. Early increases of GR-1(int)CD11b(+) and GR-1(high)CD11b(+) neutrophils were observed in the spleen, bone marrow (BM) and blood of GADD34-deficient mice. We found that BM Lin(-) c-Kit(+) Sca1(+) and Lin(-) c-Kit(+) Sca1(-)cells expressed GADD34 protein without stimulation and increased GADD34 expression following intravenous injection of Staphylococcus aureus (S.aureus). These cell populations were high in GADD34-deficient BM and were increased by the injection of S. aureus. Because of the increase in granulocyte colony-stimulating factor (G-CSF) induced by S. aureus injection, we examined the signaling pathway from the G-CSF receptor (G-CSFR). We found that phosphorylation of signal transducer and activator of transcription factor 3 was highly increased in GADD34-deficient Lin(-) BM cells by the stimulation of G-CSF. These results indicate that GADD34 binds to Lyn and inhibit G-CSFR signaling. We show here that GADD34 works to inhibit the proliferation and differentiation of HSCs or myeloid precursor cells and maintains homeostatic differentiation of neutrophil-lineage cells to avoid early immunological senescence.

The growth arrest and DNA damage-inducible protein, GADD34, has been proved to be involved in TGF-β signaling pathway and correlates with cell death, which are two important mechanisms in regulating myofibroblast differentiation and apoptosis during tissue repair. But roles of GADD34 in myofibroblasts differentiation and apoptosis remain unknown. To investigate the function of GADD34 in these processes, we subjected WT and GADD34(-/-) mice to dermal wound healing. Here we show that GADD34(-/-) mice exhibited accelerated wound closure compared with WT mice. In addition, GADD34(-/-) mice showed increased number of myofibroblasts, elevated collagen production, and decreased cell apoptosis during wound healing. Moreover, we found that GADD34(-/-) mice showed increased phosphorylation of Smad3 and lower level of cleaved caspase-3. Thus these results indicate that GADD34 appears to suppress myofibroblast differentiation through inhibiting Smad3-dependent TGFβ signal pathway and promote its apoptosis by activating caspase-3 pathway.

Background: Although pathological involvements of diabetic polyneuropathy (DPN) have been reported, no dependable treatment of DPN has been achieved. Recent studies have shown that mesenchymal stem cells (MSCs) ameliorate DPN. Here we demonstrate a differentiation of induced pluripotent stem cells (iPSCs) into MSC-like cells and investigate the therapeutic potential of the MSC-like cell transplantation on DPN., Research Design and Methods: For induction into MSC-like cells, GFP-expressing iPSCs were cultured with retinoic acid, followed by adherent culture for 4 months. The MSC-like cells, characterized with flow cytometry and RT-PCR analyses, were transplanted into muscles of streptozotocin-diabetic mice. Three weeks after the transplantation, neurophysiological functions were evaluated., Results: The MSC-like cells expressed MSC markers and angiogenic/neurotrophic factors. The transplanted cells resided in hindlimb muscles and peripheral nerves, and some transplanted cells expressed S100 β in the nerves. Impairments of current perception thresholds, nerve conduction velocities, and plantar skin blood flow in the diabetic mice were ameliorated in limbs with the transplanted cells. The capillary number-to-muscle fiber ratios were increased in transplanted hindlimbs of diabetic mice., Conclusions: These results suggest that MSC-like cell transplantation might have therapeutic effects on DPN through secreting angiogenic/neurotrophic factors and differentiation to Schwann cell-like cells.

Induced Pluripotent Stem Cells (IPSCs) open the great possibility to employ patient's own tissue to the previously incurable diseases. However these cells can be used in cell therapy only if they are not rejected when transplanted back into the syngeneic host. We found that the injection of iPSCs derived from different ages of mice into syngeneic C57BL/6 mice produced teratoma and was not rejected. Then we cultured iPSCs and myeloid differentiated iPSCs in three-dimensional porous scaffold and transplanted to C57BL/6 mice and BALB/C mice. After transplantation, we could observe the cell density inside the scaffold increased rapidly in syngeneic mice compared to the allogeneic mice indicating the favorable conditions supporting the growth of iPSCs in vivo. Unlike the allogeneic counterpart, we could not observe few infiltrating T cells inside the scaffold of syngeneic mice. These results contribute to the optimistic view of iPSCs for regenerative medicine in near future.

Thymic epithelial cells (TECs) are present in both cortical and medullary thymic areas, and have crucial roles in functional T-cell development. In this study, we studied the differentiation of induced pluripotent stem cells (iPSCs) to TEC. When iPSC were cultured for 4 days in collagen IV-coated dishes in the presence of both activin A and lithium chloride (LiCl), the cells differentiated to definitive endoderm through mesendoderm. Further treatment with Fgf8 followed by Fgf7, Fgf10 and BMP4 differentiated iPSC to thymic epithelial progenitor cells (TEPCs) by phenotype. Gene expression of Hoxa3, Pax1 and Pax9 was observed and cell surface proteins EpCAM1 and MTS24 were detected at day 14 of iPSC differentiation. TEPCs differentiated to medullary TECs (mTECs) by phenotype following the addition of receptor activator nuclear factor B ligand with LiCl. Thus, we successfully induced efficient differentiation from mouse iPSC to TEPCs and mTEC by phenotype using chemically defined conditions.

Repeated gene manipulations can be performed in yeast by excision of an introduced marker. Cassette modules containing a marker flanked by two direct repeat sequences of hisG or loxP have often been used for marker recycling, but these leave one copy of the repeats in the chromosome after excision. Genomic copies of a repeat can cause increased mistargeting of constructs containing the same repeats or unexpected chromosomal rearrangements via intra- or interchromosomal recombinations. Here, we describe a novel marker recycling procedure that leaves no scar in the genome, which we have designated seamless gene deletion. A 40 base sequence derived from an adjacent region to the targeted locus was placed in an integrating construct to generate direct repeats after integration. Seamless HIS3 deletion was achieved via a PCR fragment that consisted of a URA3 marker attached to a 40 base repeat-generating sequence flanked by HIS3 targeting sequences at both ends. Transformation of the designed construct resulted in his3 disruption and the generation of 40 base direct repeats on both sides of URA3 in the targeted locus. The resulting his3::URA3 disruptants were plated on 5-fluoroorotic acid medium to select for URA3 loss. All the selected colonies had lost URA3 precisely by recombination between the repeats, resulting in his3 deletion without any extraneous sequences left behind in the chromosome., (Copyright 2006 John Wiley & Sons, Ltd.)