Ten-eleven translocation methylcytosine dioxygenase 1 () initiates DNA demethylation by converting 5-methylcytosine (5-mC) to 5-hydroxymethylcytosine (5-hmC) at CpG-rich regions of genes, which have key roles in adult neurogenesis and memory. In addition, the overexpression of Tet1 with 5-hmC alteration in patients with psychosis has also been reported, for instance in schizophrenia and bipolar disorders. The mechanism underlying Tet1 overexpression in the brain; however, is still elusive. In the present study, we found that Tet1-transgenic (Tet1-TG) mice displayed abnormal behaviors involving elevated anxiety and enhanced fear memories. We confirmed that Tet1 overexpression affected adult neurogenesis with oligodendrocyte differentiation in the hippocampal dentate gyrus of Tet1-TG mice. In addition, Tet1 overexpression induced the elevated expression of immediate early genes, such as ,, , and, followed by the activation of intracellular calcium signals (, CamKII, ERK, and CREB) in prefrontal and hippocampal neurons. The expression of GABA receptor subunits ( and ) fluctuated in the prefrontal cortex and hippocampus. We evaluated the effects of Tet1 overexpression on intracellular calcium-dependent cascades by activating the promoter Tet1 enhanced Egr1 expression, which may have led to alterations in and expression in neurons. Taken together, we suggest that the Tet1 overexpression in our Tet1-TG mice can be applied as an effective model for studying various stress-related diseases that show hyperactivation of intracellular calcium-dependent cascades in the brain.-Kwon, W., Kim, H.-S., Jeong, J., Sung, Y., Choi, M., Park, S., Lee, J., Jang, S., Kim, S. H., Lee, S., Kim, M. O., Ryoo, Z. Y. Tet1 overexpression leads to anxiety-like behavior and enhanced fear memories the activation of calcium-dependent cascade through Egr1 expression in mice.

TALLYHO/JngJ (TallyHo) mouse is a recently established animal model for type 2 diabetes mellitus (T2DM) with phenotypes of mild obesity and male-limited hyperglycemia. In this study, we investigated how obesity develops in TallyHo mice by measuring parameters of food intake and energy expenditure. At 4 weeks of age, TallyHo mice were heavier than control C57BL/6 mice with increased food intake but comparable energy expenditure parameters, such as body temperature, cold-induced thermogenesis, oxygen consumption rate (VO(2)) and spontaneous locomotor activity. Furthermore, pair-fed TallyHo mice, which were fed the same amount of food as C57BL/6 mice, showed similar patterns of body weight gain to C57BL/6 mice at all ages, implying that obesity in TallyHo mice may develop by increased food intake but not by decreased energy consumption. TallyHo mice appear to have hypothalamic leptin resistance at 4 weeks of age, as indicated by the increased expression of orexigenic neuropeptides in the hypothalamus and no alteration of food intake and neuropeptide expression upon intravenous leptin treatment. Leptin injection to TallyHo mice, however, increased the phosphorylation of STAT3 and Akt, an important signaling mediator of leptin, in a pattern similar to that in C57BL/6 mice. In conclusion, increased food intake is a crucial component in the development of obesity in TallyHo mice, in which central leptin resistance, possibly caused by uncoupling between activation of leptin signaling and neuropeptide expression, might be involved.

Juxtaposed with another zinc finger protein 1 (Jazf1) is a zinc finger protein and is known to affect both prostate cancer and type 2 diabetes. Jazf1 inhibits testicular nuclear receptor 4 (TR4) activation through protein-protein interaction, which results in weight loss and alleviates diabetes. However, the role of Jazf1 in prostate cancer is still poorly understood. Hence, we investigated whether the expression of Jazf1 is associated with prostate cancer progression. We confirmed the upregulation of Jazf1 expression in human prostate tissue samples. In addition, using Jazf1 overexpressing prostate cancer cell lines, DU145 and LNCaP, we found Jazf1 promoted cell proliferation and colony formation ability. We also observed that Jazf1 dramatically enhanced cell migration and invasion in transwell assays. Additionally, we checked the upregulation of vimentin and downregulation of E-cadherin expression in Jazf1-overexpressing DU145 and LNCaP cells. Moreover, we found that Slug, which is known to be regulated by JNK/c-Jun phosphorylation, was upregulated in the microarray analysis of two prostate cancer cell lines. Jazf1 promotes the phosphorylation of JNK/c-Jun, likely promoting cell proliferation and invasion through Slug. In a xenograft model, tumors overexpressing Jazf1 were larger than control tumors, and tumors with decreased Jazf1 were smaller. These data indicated that Jazf1 enhances prostate cancer progression and metastasis via regulating JNK/Slug signaling. Taken together, these results suggest that Jazf1 plays an important role in both androgen dependent and independent prostate cancer.

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Lin28, which is highly expressed during embryogenesis, has been shown to play an important role in cell growth and embryonic development. Meanwhile, Lin28 represses let-7 miRNA biogenesis and block pre-let-7 processing in the cytoplasm.The let-7 family of miRNAs is known to repress oncogenesis and cell cycle progression by targeting oncogenic genes and signalling pathways. Consequently, Lin28 acts as an oncogene by upregulating let-7 targets through the repression of let-7 biogenesis. A recent genome-wide association study (GWAS) showed that many genes related to Type 2 diabetes (T2D) are also oncogenes or cell cycle regulators. The role of Lin28 in mouse growth and glucose metabolism in metabolic-related tissues has also been studied. In these studies, whole-body Lin28 overexpression was found to promote glucose utilization and prevent weight gain by inhibiting let-7 biogenesis.Furthermore, Lin28 has been found to directly stimulate skeletal myogenesis and cell growth. Therefore, we determined whether similar effects mediated by Lin28a, which is essential for cell growth and proliferation, may also apply to pancreatic ß-cells. We found that overexpression of Lin28a protects pancreatic β-cells from streptozotocin (STZ)-induced β-cell destruction in vitro and in vivo. Furthermore, Lin28aoverexpressing transgenic (Tg) mice had higher insulin secretion in the presence of glucose than in control mice. Our findings suggest that the Lin28/let-7 axis is an important regulator of pancreatic β-cell functions and that precise modulation of this axis may be helpful in treating metabolic diseases such as diabetes.Significance of the study: We demonstrate that Lin28a prevents pancreatic β-cell death against streptozotocin (STZ)-induced β-cell destruction in vitro and in vivo. Furthermore, Lin28a promotes cell survival and proliferation by activating the PI3K-Akt signalling pathway, which may be dependent on let-7 regulation. Taken together, our results imply that the Lin28a/let-7 axis is an important regulator of pancreatic β-cell functions and that precise modulation of this axis may be helpful in treating metabolic diseases such as diabetes.