Retinoids ameliorate insulin resistance in a leptin-dependent manner in mice.

UNLABELLED: Transgenic mice expressing dominant-negative retinoic acid receptor (RAR) α specifically in the liver exhibit steatohepatitis, which leads to the development of liver tumors. Although the cause of steatohepatitis in these mice is unknown, diminished hepatic expression of insulin-like growth factor-1 suggests that insulin resistance may be involved. In the present study, we examined the effects of retinoids on insulin resistance in mice to gain further insight into the mechanisms responsible for this condition. Dietary administration of all-trans-retinoic acid (ATRA) significantly improved insulin sensitivity in C57BL/6J mice, which served as a model for high-fat, high-fructose diet-induced nonalcoholic fatty liver disease (NAFLD). The same effect was observed in genetically insulin-resistant KK-A(y) mice, occurring in concert with activation of leptin-signaling pathway proteins, including signal transducer and activator of transcription 3 (STAT3) and Janus kinase 2. However, such an effect was not observed in leptin-deficient ob/ob mice. ATRA treatment significantly up-regulated leptin receptor (LEPR) expression in the livers of NAFLD mice. In agreement with these observations, in vitro experiments showed that in the presence of leptin, ATRA directly induced LEPR gene expression through RARα, resulting in enhancement of STAT3 and insulin-induced insulin receptor substrate 1 phosphorylation. A selective RARα/ß agonist, Am80, also enhanced hepatic LEPR expression and STAT3 phosphorylation and ameliorated insulin resistance in KK-A(y) mice. CONCLUSION: We discovered an unrecognized mechanism of retinoid action for the activation of hepatic leptin signaling, which resulted in enhanced insulin sensitivity in two mouse models of insulin resistance. Our data suggest that retinoids might have potential for treating NAFLD associated with insulin resistance.

A Case of Pediatric Garré's Osteomyelitis Caused by Germ Infection in the Lower Impacted Wisdom Tooth.

Garré's osteomyelitis, first described by Carl Garré in 1893, is a type of chronic osteomyelitis accompanied by hyperplastic periostitis. This condition affects relatively young patients and occurs in the fibula, femur, and other long bones as chronic non-purulent sclerosing osteomyelitis. Further, reactive periosteal bone formation develops due to chronic irritation or infection. In the maxillofacial region, it often occurs in the first molar region of the mandible due to caries and other similar causes, and it is rarely associated with impacted teeth. Herein, we present a 12-year-old female patient who primarily complained of swelling on the right side of the mandible. Despite taking antibiotics prescribed at local otolaryngologist, the swelling did not completely resolve. Thus, the patient was referred to the Department of Otorhinolaryngology at our hospital, where a dental-related disease was suspected. On a computed tomography scan, radiolucent findings were observed around the germ of the impacted wisdom tooth as well as hyperostosis in the lower jaw. Thus, Garré's osteomyelitis was suspected. The patient received oral anti-inflammatory treatment by the incision prior to surgery. Thereafter, the tooth germ was enucleated and newly-formed bone, which was laterally located to the cortical bone of the mandible, was removed under the effect of general anesthesia. On computed tomography scan 9 months after the surgery, hyperostosis in the angle of the mandible disappeared. Thereafter, pain and swelling did not recur, and the patient was doing well.

A Case Report of Atypical Spindle Cell Lipomatous Tumor of the Tongue.

Herein, we report a case of atypical spindle cell lipomatous tumor (ASCLT) on both sides of the tongue in a 74-year-old male patient. The patient was referred to our department for treatment of the masses in the tongue. Several elastic soft indolent masses were detected during the first examination. The masses were well defined, and their consistency was similar to that of adipose tissues. No signs of induration were observed in the surrounding tissues. The patient was not aware of the masses, which were only detected during his visit at the dental clinic that referred him to our institution. Thus, the onset of the masses remains unknown. ASCLT was identified via histopathological examination. Then, tumor excision was performed under general anesthesia. Thirteen months after surgery, the condition of the patient was good, and signs of local recurrence or postoperative metastasis were not observed.

Hepatic differentiation of human bone marrow-derived mesenchymal stem cells by tetracycline-regulated hepatocyte nuclear factor 3beta.

UNLABELLED: 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 3beta (HNF3beta), a forkhead/winged helix transcription factor, is essential for liver development. In the present study, we established a tetracycline (Tet)-regulated expression system for HNF3beta in UE7T-13 BM-MSCs. HNF3beta expression significantly enhanced expression of albumin, alpha-fetoprotein (AFP), tyrosine amino transferase (TAT) and epithelial cell adhesion molecule (EpCAM) genes. The differentiated cells showed hepatocyte-specific functions including glycogen production and urea secretion. During treatment with the Tet-on system for 8 days, over 80% of UE7T-13 cells turned out to express albumin. Furthermore, the combination of Tet with basic fibroblast growth factor (bFGF) efficiently induced the genes such as albumin and TAT, which are associated with maturity of hepatocytes; however, it suppressed genes such as AFP and EpCAM, which are associated with immaturity of hepatocytes, suggesting that Tet-induced HNF3beta expression sensitizes BM-MSCs to bFGF signals. Finally, the results of the present study suggest that down-regulation of Wnt/beta-catenin signals caused by translocation of beta-catenin to cytoplasmic membrane is associated with hepatic differentiation of human BM-MSCs. CONCLUSION: HNF3beta expression induced efficient differentiation of UE7T-13 human BM-MSCs.

Involvement of N-acetyltransferase human in the cytotoxic activity of 5-fluorouracil.

N-acetyltransferase human (NATH) participates in a posttranslational modification of the proteins and has been reported to play a role in apoptosis. In this study, the involvement of NATH in the cytotoxic action of 5-fluorouracil (5-FU) in human squamous cell carcinoma HEp-2 cells was examined. We found that 5-FU decreased NATH expression in a dose-dependent and time-dependent manner. No change was observed after treatment with bleomycin, nedaplatin, mitomycin C, or methotrexate. Interestingly, knockdown of NATH by small interfering RNA resulted in the downregulation of thymidylate synthase mRNA expression and induced apoptosis. Conversely, NATH overexpression facilitated cell proliferation independent of the presence of 5-FU. The effect of NATH knockdown on the expression of proteins in HEp-2 cells was examined using two-dimensional gel electrophoresis and mass spectrometry. Profilin 1, CutA, ras-related nuclear protein, annexin A5, enolase 1, and elongation factor 1 alpha 1 were found to be upregulated and 14-3-3eta, tublin, nuclear auto antigenic sperm protein, heat shock protein 70, and heat shock protein 90 were downregulated by knockdown of NATH. The results of this study suggest that NATH plays an important role in the cytotoxic activity of 5-FU.

Synthetic retinoid CD437 induces mitochondria-mediated apoptosis in hepatocellular carcinoma cells.

Retinoids play an important role in the regulation of cell growth and death. Synthetic retinoid CD437 reportedly induces apoptosis in various cancer cell lines. However, the mechanism of inducing apoptosis in hepatocellular carcinoma (HCC) cells by this agent remains to be clarified. In this study, we investigated the signaling pathway by which CD437 induces apoptosis in HCC cell lines. Apoptosis of six human HCC cell lines was induced by treatment with CD437. Caspase-3 and -9 were activated by CD437, suggesting that the apoptosis is mediated by mitochondrial pathways. Consistent with these findings, the treatment with CD437 upregulated Bax protein, downregulated Bcl-2 protein and released cytochrome c into the cytoplasm. Moreover, rhodamine123 staining revealed mitochondrial depolarization in the cells treated with CD437. These data of the present study suggest that CD437 induces apoptosis in HCC cells via mitochondrial pathways.

CD437 induces apoptosis in ovarian adenocarcinoma cells via ER stress signaling.

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.

An antioxidant effect by acyclic retinoid suppresses liver tumor in mice.

The mechanisms of prevention of the development of liver cancer by NIK-333, an acyclic retinoid (ACR), were investigated. The transgenic mice expressing the dominant negative form of retinoic acid receptor alpha (RARE mice), that produce reactive oxygen species and lead to development of liver tumor were used. The effect of NIK-333 on hepatocarcinogenesis in RARE mice was studied. The RARE mice were examined after feeding 0.03% and 0.06% NIK-333 diets at 12 months of age. In the mice fed 0.06% NIK-333 diet, tumor incidence was greatly suppressed, compared to that of wild type mice (0/9 versus 5/9, P<0.05), but not in the mice fed 0.03% NIK-333 diet. In addition, expression of cytochrome p450 4a14 and acyl-CoA oxidase was normalized, and the percentages of positive cells for 8-hydroxy-2'-deoxyguanosine, 4-hydroxy-2-nonenal and proliferating cell nuclear antigen were decreased. Furthermore, expression of beta-catenin and cyclin D1 was also depressed. These data suggest that NIK-333 suppressed liver tumor in association with repression of oxidative stress.

Hepatic differentiation of human bone marrow-derived UE7T-13 cells: Effects of cytokines and CCN family gene expression.

AIM: Bone marrow-derived mesenchymal stem cells (MSC) are expected to be an excellent source of cells for transplantation. We aimed to study the culture conditions and involved genes to differentiate MSC into hepatocytes. METHODS: The culture conditions to induce the efficient differentiation of human bone marrow-derived UE7T-13 cells were examined using cytokines, hormones, 5-azacytidine and type IV collagen. RESULTS: We found that combination of acidic fibroblast growth factor (aFGF), basic fibroblast growth factor (bFGF) and hepatocyte growth factor (HGF) with type IV collagen coating induced hepatic differentiation of UE7T-13 cells at over 30% frequency, where expression of albumin mRNA was increased over 20-fold. The differentiated cells had functions of albumin production, glycogen synthesis and urea secretion as well as expressing hepatocyte-specific genes. In addition, these cellshave binuclear and cuboidal morphology, which is a characteristic feature of hepatocytes. During hepatic differentiation, UE7T-13 cells showed depressed expression of WISP1 and WISP2 genes, members of the CCN family. Conversely, knockdown of WISP1 or WISP2 gene by siRNA stimulated hepatic differentiation. The effect of aFGF/bFGF/HGF/type IV collagen coating and WISP1-siRNA on hepatic differentiation was additive. CONCLUSION: The present study suggests that aFGF/bFGF/HGF/type IV collagen coating is the efficient condition for hepatic differentiation of UE7T-13 cells, and that WISP1 and WISP2 play an important role in hepatic transdifferentiation of these cells.

Involvement of microRNAs in regulation of osteoblastic differentiation in mouse induced pluripotent stem cells.

UNLABELLED: BACKGOROUND: MicroRNAs (miRNAs), which regulate biological processes by annealing to the 3'-untranslated region (3'-UTR) of mRNAs to reduce protein synthesis, have been the subject of recent attention as a key regulatory factor in cell differentiation. The effects of some miRNAs during osteoblastic differentiation have been investigated in mesenchymal stem cells, however they still remains to be determined in pluripotent stem cells. METHODOLOGY/PRINCIPAL FINDINGS: Bone morphogenic proteins (BMPs) are potent activators of osteoblastic differentiation. In the present study, we profiled miRNAs during osteoblastic differentiation of mouse induced pluripotent stem (iPS) cells by BMP-4, in which expression of important osteoblastic markers such as Rux2, osterix, osteopontin, osteocalcin, PTHR1 and RANKL were significantly increased. A miRNA array analysis revealed that six miRNAs including miR-10a, miR-10b, miR-19b, miR-9-3p, miR-124a and miR-181a were significantly downregulated. Interestingly, miR-124a and miR-181a directly target the transcription factors Dlx5 and Msx2, both of which were increased by about 80-and 30-fold, respectively. In addition, transfection of miR-124a and miR-181a into mouse osteo-progenitor MC3T3-E1 cells significantly reduced expression of Dlx5, Runx2, osteocalcin and ALP, and Msx2 and osteocalcin, respectively. Finally, transfection of the anti-miRNAs of these six miRNAs, which are predicted to target Dlx5 and Msx2, into mouse iPS cells resulted in a significant increase in several osteoblastic differentiation markers such as Rux2, Msx2 and osteopontin. CONCLUSIONS/SIGNIFICANCE: In the present study, we demonstrate that six miRNAs including miR-10a, miR-10b, miR-19b, miR-9-3p, miR-124a and miR-181a miRNAs, especially miR-124a and miR-181a, are important regulatory factors in osteoblastic differentiation of mouse iPS cells.

A role of Wnt/beta-catenin signals in hepatic fate specification of human umbilical cord blood-derived mesenchymal stem cells.

Human umbilical cord blood-derived mesenchymal stem cells (UCBMSCs) are expected to be an excellent source of cells for transplantation. In addition, the stem cell plasticity of human UCBMSCs, which can transdifferentiate into hepatocytes, has been reported. However, the mechanisms involved remain to be clarified. To identify the genes and/or signals that are important in specifying the hepatic fate of human UCBMSCs, we analyzed gene expression profiles during the hepatic differentiation of UCBMSCs with human telomerase reverse transcriptase, UCBMSCs immortalized by infection with a retrovirus carrying telomerase reverse transcriptase, but whose differentiation potential remains unchanged. Efficient differentiation was induced by 5-azacytidine (5-aza)/hepatocyte growth factor (HGF)/oncostatin M (OSM)/fibroblast growth factor 2 (FGF2) treatment in terms of function as well as protein expression: 2.5-fold increase in albumin, 4-fold increase in CCAAT enhancer-binding protein alpha, 1.5-fold increase in cytochrome p450 1A1/2, and 8-fold increase in periodic acid-Schiff staining. Consequently, we found that the expression of Wnt/beta-catenin-related genes downregulated, and the translocation of beta-catenin was observed along the cell membrane and in the cytoplasm, although some beta-catenin was still in the nucleus. Downregulation of Wnt/beta-catenin signals in the cells by Fz8-small interference RNA treatment, which was analyzed with a Tcf4 promoter-luciferase assay, resulted in similar hepatic differentiation to that observed with 5-azacytidine/HGF/OSM/FGF2. In addition, the subcellular distribution of beta-catenin was similar to that of cells treated with 5-azacytidine/HGF/OSM/FGF2. In conclusion, the suppression of Wnt/beta-catenin signaling induced the hepatic differentiation of UCBMSCs, suggesting that Wnt/beta-catenin signals play an important role in the hepatic fate specification of human UCBMSCs.