Autosomal-dominant spinocerebellar ataxias (SCAs) are a heterogeneous group of neurodegenerative disorders. In this study, we performed genetic analysis of a unique form of SCA (SCA36) that is accompanied by motor neuron involvement. Genome-wide linkage analysis and subsequent fine mapping for three unrelated Japanese families in a cohort of SCA cases, in whom molecular diagnosis had never been performed, mapped the disease locus to the region of a 1.8 Mb stretch (LOD score of 4.60) on 20p13 (D20S906-D20S193) harboring 37 genes with definitive open reading frames. We sequenced 33 of these and observed a large expansion of an intronic GGCCTG hexanucleotide repeat in NOP56 and an unregistered missense variant (Phe265Leu) in C20orf194, but we found no mutations in PDYN and TGM6. The expansion showed complete segregation with the SCA phenotype in family studies, whereas Phe265Leu in C20orf194 did not. Screening of the expansions in the SCA cohort cases revealed four additional occurrences, but none were revealed in the cohort of 27 Alzheimer disease cases, 154 amyotrophic lateral sclerosis cases, or 300 controls. In total, nine unrelated cases were found in 251 cohort SCA patients (3.6%). A founder haplotype was confirmed in these cases. RNA foci formation was detected in lymphoblastoid cells from affected subjects by fluorescence in situ hybridization. Double staining and gel-shift assay showed that (GGCCUG)n binds the RNA-binding protein SRSF2 but that (CUG)(6) does not. In addition, transcription of MIR1292, a neighboring miRNA, was significantly decreased in lymphoblastoid cells of SCA patients. Our finding suggests that SCA36 is caused by hexanucleotide repeat expansions through RNA gain of function.

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Human bone marrow-derived mesenchymal stem cells (BM-MSCs) are expected to be a potential source of cells for transplantation. Although recent reports have shown that isolated MSCs can differentiate into hepatocytes, the efficiency of differentiation is insufficient for therapeutic application. To circumvent this problem, it is necessary to understand the mechanisms of hepatic differentiation of human BM-MSCs. Hepatocyte nuclear factor 3␤ (HNF3␤), a forkhead/winged helix transcription factor, is essential for liver development. In the present study, we established a tetracycline (

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A synthetic retinoid, CD437, has been shown to exert potent anti-tumor activity against various types of cancer cell lines, regardless of their sensitivities to natural retinoids. We herein demonstrate that CD437 induces endoplasmic reticulum (ER) stress, including the up-regulation of CHOP, BIP and GADD34 mRNA through ER stress transducer (PERK and IRE1alpha) activation in an ovarian adenocarcinoma cell line, SKOV3. It was also shown that CD437 induced the CHOP and GADD34 expressions in another four ovarian adenocarcinoma cell lines, indicating that CD437 functions as an ER stress inducer in these cell lines. Moreover, the siRNA-mediated knockdown of inducible CHOP expression prevented the cytotoxic effect of CD437. These results suggest that ER stress plays an important role in the mechanism by which CD437 induces apoptosis in ovarian adenocarcinoma cells.

CD437, a synthetic retinoid, has a potent antitumor activity, in which an RAR-independent mechanism may be involved. Our previous study showed that CD437 transcriptionally upregulates the expression of thioredoxin-binding protein 2 (TBP2), leading to c-Jun N-terminal kinase 1 (JNK1)-mediated apoptosis. In the present study, we addressed the mechanism, by which CD437 induces TBP2 mRNA expression. CD437 efficiently caused the cell death of human osteosarcoma cells via apoptosis. CD437 also induced JNK1 activation through the upregulation of TBP2 mRNA, in consistent with our previous observation. A luciferase reporter assay for TBP2 promoter activation suggested that CD437-regulated TBP2 mRNA transcription requires the region between -400 and -300, which contains multiple possible ETS-binding sites. Finally, we demonstrated CD437-dependent recruitment of ETS1 transcription factor to this region by chromatin immunoprecipitation assay. These data suggest that ETS1 is involved in CD437-induced TBP2 mRNA expression in human osteosarcoma MG-63 cells.

Oxidative stress is considered as a major causative factor in the progression of chronic liver diseases. A recent observation of hepatic iron overload in patients with alcoholic liver disease, chronic hepatitis C and nonalcoholic steatohepatitis (NASH), suggests that iron-induced oxidative stress plays an important role in the pathogenesis of chronic liver diseases.1) We have previously reported that a transgenic mouse, which develops steatohepatitis by liver-specific impairment of retinoid signaling, shows significant hepatic iron overload.2,3) It is also known that abnormal lipid metabolism and iron metabolism frequently coexist in chronic liver diseases, although it remains unclear whether the iron metabolism is related to the lipid metabolism in the liver. Choline is an essential nutrient with roles in cell membrane integrity, transmembrane signaling, phosphatidylcholine synthesis and methyl metabolism. The role of dietary choline deficiency in promoting hepatic steatosis and reduced plasma VLDL levels is well established, and the mice fed a choline-deficient diet (CD mice) has been used as a model for non-alcoholic fatty liver disease (NAFLD). 4)Accumulating evidence suggests that dysregulation of hepcidin (HEPC) expression is one of the primary causes of hepatic iron overload. 5) Hemojuvelin (HJV), transferrin receptor 2 (TfR2) and hepatocellular iron content have been reported to be positive regulators of HEPC expression while transmembrane serine protease 6 (TMPRSS6) is its negative regulator. [6][7][8] It is thought that HEPC decreases total body iron amount by inhibiting iron absorption through cellular iron exporter ferroportin (FPN) expressed on the basolateral membrane of small intestinal epithelial cells. 9) Our previous results suggested that FPN, which is present in the liver, plays a role in hepatic iron efflux.2) In addition, the genes, whose expression is regulated through iron responsive element (IRE), such as transferrin receptor 1 (Tfr1), ferritin light chain (Ftl) and divalent metal ion transporter 1 (Dmt1), 10) are expected to be altered in accordance with hepatic iron accumulation. Since FPN is also an IRE-regulated gene, 10) its regulation seems to be complicated. In the present study, we try to clarify the possible link between iron and lipid metabolism in steatotic livers of CD mice. MATERIALS AND METHODS Animal TreatmentSix weeks old male C57BL/6J mice (CLEA Japan, Tokyo, Japan) were fed with normal diet (CE-2, CLEA Japan; nϭ6) or CD diet (Dyets Inc., Bethlehem, PA, U.S.A.; nϭ9) for 12 weeks. The mice were kept under pathogen-free conditions, and were maintained in a temperature-controlled room with a 12 h light/dark illumination cycle. Animals received humane care in accordance with study guidelines established by the Tottori University Subcommittee on Laboratory Animal Care.Biochemical Analysis Determination of hepatic nonheme iron using bathophenantrolinedisulfonate was performed according to the previous report.2) Hepatic non-escerified fatty acid (NEFA) and triglyceride (TG) con...