S6K1 Phosphorylation of H2B Mediates EZH2 Trimethylation of H3: A Determinant of Early Adipogenesis.

S6K1 has been implicated in a number of key metabolic responses, which contribute to obesity. Critical among these is the control of a transcriptional program required for the commitment of mesenchymal stem cells to the adipocytic lineage. However, in contrast to its role in the cytosol, the functions and targets of nuclear S6K1 are unknown. Here, we show that adipogenic stimuli trigger nuclear translocation of S6K1, leading to H2BS36 phosphorylation and recruitment of EZH2 to H3, which mediates H3K27 trimethylation. This blocks Wnt gene expression, inducing the upregulation of PPARγ and Cebpa and driving increased adipogenesis. Consistent with this finding, white adipose tissue from S6K1-deficient mice exhibits no detectable H2BS36 phosphorylation or H3K27 trimethylation, whereas both responses are highly elevated in obese humans or in mice fed a high-fat diet. These findings define an S6K1-dependent mechanism in early adipogenesis, contributing to the promotion of obesity.

SAR ATR for Limited Training Data Using DS-AE Network.

Although automatic target recognition (ATR) with synthetic aperture radar (SAR) images has been one of the most important research topics, there is an inherent problem of performance degradation when the number of labeled SAR target images for training a classifier is limited. To address this problem, this article proposes a double squeeze-adaptive excitation (DS-AE) network where new channel attention modules are inserted into the convolutional neural network (CNN) with a modified ResNet18 architecture. Based on the squeeze-excitation (SE) network that employs a representative channel attention mechanism, the squeeze operation of the DS-AE network is carried out by additional fully connected layers to prevent drastic loss in the original channel information. Then, the subsequent excitation operation is performed by a new activation function, called the parametric sigmoid, to improve the adaptivity of selective emphasis of the useful channel information. Using the public SAR target dataset, the recognition rates from different network structures are compared by reducing the number of training images. The analysis results and performance comparison demonstrate that the DS-AE network showed much more improved SAR target recognition performances for small training datasets in relation to the CNN without channel attention modules and with the conventional SE channel attention modules.

Reversine induces multipotency of lineage-committed cells through epigenetic silencing of miR-133a.

Reversine has been shown to induce dedifferentiation of C2C12 murine myoblasts into multipotent progenitor cells. However, little is known about the key regulators mediating the dedifferentiation induced by reversine. Here, we show that large scale miRNA gene expression profiling of reversine-treated C2C12 myoblasts identifies a down-regulated miRNA, miR-133a, involved in dedifferentiation of myoblasts. Reversine treatment results in up- and down-regulated miRNA profiles. Among miRNAs affected by reversine, the level of muscle-specific miR-133a, which has been shown to be up-regulated during muscle development and to suppress differentiation into other lineages, is markedly reduced by treatment of C2C12 myoblasts with reversine. In parallel, reversine decreases the expression and recruitment of myogenic factor, SRF, to the enhancer regions of miR-133a. Sequentially, down-regulation of miR-133a by reversine is accompanied by a decrease in active histone modifications including trimethylation of histone H3K4 and H3K36, phosphorylation of H3S10, and acetylation of H3K14 on the miR-133a promoter, leading to dissociation of RNA polymerase II from the promoter. Furthermore, inhibition of miR-133a by transfection of C2C12 myoblasts with miR-133a inhibitor increases the expression of osteogenic lineage marker, Ogn, and adipotenic lineage marker, ApoE, similar to that in response to reversine. In contrast, the co-overexpression of miR-133a mimic reversed the effect of reversine on C2C12 myoblast dedifferentiation. Taken together, the results indicate that reversine induces a multipotency of C2C12 myoblasts by suppression of miR-133a expression through depletion of active histone modifications, and suggest that miR-133a is a potential miRNA regulating the reversine-induced dedifferentiation. Collectively, our findings provide a mechanistic rationale for the application of reversine to dedifferentiation of somatic cells.

Requirement of protein l-isoaspartyl O-methyltransferase for transcriptional activation of trefoil factor 1 (TFF1) gene by estrogen receptor alpha.

Lysine- and arginine-specific methyltransferases have been shown to act as either direct or secondary transcriptional co-activator of the estrogen receptor (ERα). However, little is known about the role of protein l-isoaspartyl O-methyltransferase (PIMT) on transcriptional regulation. Here, we show that PIMT acts as a co-activator for ERα-mediated transcription. Activation of the estrogen response element (ERE) promoter by ß-estradiol (E(2)) was suppressed by knockdown of PIMT, and enhanced by overexpression of wild-type PIMT. However, the ERE promoter activity was resistant to E(2) stimulation in cells overexpressing a catalytically inactive PIMT mutant, G88A. Consistent with these results, the expression of the endogenous ERα response gene trefoil factor 1 (TFF1) by E(2) was completely abrogated by PIMT depletion and decreased to approximately 50% when PIMT mutant G88A was expressed. In addition, over-expression of PIMT significantly increased the levels of TFF1 mRNA in the presence or absence of E(2). Interestingly, PIMT interacted with ERα and was distributed to the cytosol and the nucleus. The chromatin immunoprecipitation analysis revealed that PIMT was recruited to the promoter of TFF1 gene together with ERα in an E(2)-dependent manner, which was accompanied by uploading of RNA polymerase II on the promoter. Taken together, the results suggest that PIMT may act as a co-activator in ERα-mediated transcription through its recruitment to the promoter via interacting with ERα.

Peripheral blood NK cell cytotoxicities are negatively correlated with CD8(+) T cells in fertile women but not in women with a history of recurrent pregnancy loss.

PROBLEM: We aim to investigate NK cell cytolytic activities and its relationship to other lymphocyte subsets in peripheral blood of women with a history of recurrent pregnancy loss (RPL). METHODS OF STUDY: Women with a history of RPL (n = 48) comprised RPL group, and 15 fertile women served as controls. Lymphocyte subsets such as T (CD3(+)), T helper (CD3(+)/4(+)), cytotoxic T (CD3(+)/8(+)), NK (CD3(-)/56(+)), and peripheral blood NK cell cytolytic activities at three different effector to target cell ratios (E/T ratio, 50:1, 25:1 and 12.5:1) are measured by flow cytometric analysis. RESULTS: Peripheral blood NK cell levels are significantly increased in women with RPL as compared to controls (P = 0.001). NK cell cytolytic activities in RPL group are significantly increased as compared to those of controls at E/T ratio of 50:1 (42.5 ± 16.3 versus 29.9 ± 13.8, P = 0.009), 25:1 (31.6 ± 15.0 versus 19.4 ± 10.1, P = 0.004), and 12.5:1 (20.1 ± 10.9 versus 12.3 ± 7.5, P = 0.011). In RPL group, peripheral blood NK cell levels (%) showed a significant positive correlation with NK cell cytolytic activities at E/T ratio of 50:1 (r = 0.522, P < 0.001), 25:1 (r = 0.588, P < 0.001), and 12.5:1 (r = 0.604, P < 0.001). In controls, CD3(+)/8(+) cells (%) show a negative correlation with NK cell cytolytic activities at E/T ratio of 50:1 (r = -0.566, P = 0.028), 25:1 (r = -0.60., P = 0.017), and 12.5:1 (r = -0.602, P = 0.018). Ratios of T-helper cell to T-cytotoxic cell are positively correlated with NK cell cytolytic activities at E/T ratio of 50:1 (r = 0.601, P = 0.018), 25:1 (r = 0.632, P = 0.012), and 12.5:1 (r = 0.637, P = 0.011). CONCLUSION: NK cell-mediated immunopathology plays a role in RPL. Women with RPL have a disrupted immune regulation between cytotoxic T and NK cells. Failure of immune modulation by CD8(+) T cells may exert NK cell activation and reproductive failures in women with RPL.

Age specific serum anti-Müllerian hormone levels in 1,298 Korean women with regular menstruation.

OBJECTIVE: To determine the age specific serum anti-Müllerian hormone (AMH) reference values in Korean women with regular menstruation. METHODS: Between May, 2010 and January, 2011, the serum AMH levels were evaluated in a total of 1,298 women who have regular menstrual cycles aged between 20 and 50 years. Women were classified into 6 categories by age: 20-31 years, 32-34 years, 35-37 years, 38-40 years, 41-43 years, above 43 years. Measurement of serum AMH was measured by commercial enzyme-linked immunoassay. RESULTS: The serum AMH levels correlated negatively with age. The median AMH level of each age group was 4.20 ng/mL, 3.70 ng/mL, 2.60 ng/mL, 1.50 ng/mL, 1.30 ng/mL, and 0.60 ng/mL, respectively. The AMH values in the lower 5th percentile of each age group were 1.19 ng/mL, 0.60 ng/mL, 0.42 ng/mL, 0.27 ng/mL, 0.14 ng/mL, and 0.10 ng/mL, respectively. CONCLUSION: This study determined reference values of serum AMH in Korean women with regular menstruation. These values can be applied to clinical evaluation and treatment of infertile women.

Serum anti-Müllerian hormone levels as a predictor of the ovarian response and IVF outcomes.

OBJECTIVE: The aim of this study was to investigate whether anti-Mullerian hormone (AMH) levels could be predict ovarian poor/hyper response and IVF cycle outcome. METHODS: Between May 2010 and January 2011, serum AMH levels were evaluated with retrospective analysis. Three hundred seventy infertile women undergoing 461 IVF cycles between the ages of 20 and 42 were studied. We defined the poor response as the number of oocytes retrieved was equal or less than 3, and the hyper response as more than 25 oocytes retrieved. Serum AMH was measured by commercial enzyme-linked immunoassay. RESULTS: The number of oocytes retrieved was more correlated with the serum AMH level (r=0.781, p<0.01) than serum FSH (r=-0.412, p<0.01). The cut-off value of serum AMH levels for poor response was 1.05 ng/mL (receiver operating characteristic [ROC] curves/area under the curve [AUC], ROC(AUC)=0.85, sensitivity 74%, specificity 87%). Hyper response cut-off value was 3.55 ng/mL (ROC(AUC)=0.91, sensitivity 94%, specificity 81%). When the study group was divided according to the serum AMH levels (low: <1.05 ng/mL, middle: 1.05 ng/mL - 3.55 ng/mL, high: >3.55 ng/mL), the groups showed no statistical differences in mature oocyte rates (71.6% vs. 76.5% vs. 74.8%) or fertilization rates (76.9% vs. 76.6% vs. 73.8%), but showed significant differences in clinical pregnancy rates (21.7% vs. 24.1% vs. 40.8%, p=0.017). CONCLUSION: The serum AMH level can be used to predict the number of oocytes retrieved in patients, distinguishing poor and high responders.

Comparison of mild ovarian stimulation with conventional ovarian stimulation in poor responders.

OBJECTIVE: To compare the IVF outcomes of mild ovarian stimulation with conventional ovarian stimulation in poor responders. METHODS: From 2004 to 2009, 389 IVF cycles in 285 women showed poor responses (defined as either a basal FSH level ≥12 mIU/mL, or the number of retrieved oocytes ≤3, or serum E(2) level on hCG day <500 pg/mL) were analyzed, retrospectively. In total, 119 cycles with mild ovarian stimulation (m-IVF) and 270 cycles with conventional ovarian stimulation (c-IVF) were included. Both groups were divided based on their age, into groups over and under 37 years old. RESULTS: The m-IVF group was lower than the c-IVF group in the duration of stimulation, total doses of gonadotropins used, serum E(2) level on hCG day, the number of retrieved oocytes, and the number of mature oocytes. However, there was no significant difference in the number of good embryos, the number of transferred embryos, the cancellation rate, or the clinical pregnancy rate. In the m-IVF group over 37 years old, the clinical pregnancy rate and live birth rate were higher when compared with the c-IVF group, but this result was not statistically significant. CONCLUSION: In poor responder groups, mild ovarian stimulation is more cost effective and patient friendly than conventional IVF. Therefore, we suggest that mild ovarian stimulation could be considered for poor responders over 37 years old.

Serum anti-Müllerian hormone is a better predictor of ovarian response than FSH and age in IVF patients with endometriosis.

OBJECTIVE: To evaluate the ability of serum anti-Müllerian hormone (AMH), FSH, and age to clinically predict ovarian response to controlled ovarian hyperstimulation (COH) in IVF patients with endometriosis. METHODS: We evaluated 91 COH cycles, including 43 cycles with endometriosis (group I) and 48 cycles with male factor infertility (group II) from January to December, 2010. Patients were classified into study groups based on their surgical history of endometriosis-group Ia (without surgical history, n=16), group Ib (with a surgical history, n=27). RESULTS: The mean age was not significantly different between group I and group II. However, AMH and FSH were significantly different between group I and group II (1.9±1.9 ng/mL vs. 4.1±2.9 ng/mL, p<0.01; 13.1±7.2 mIU/mL vs. 8.6±3.3 mIU/mL, p<0.01). Furthermore, the number of retrieved oocytes and the number of matured oocytes were significantly lower in group I than in group II. In group II, AMH and FSH as well as age were significant predictors of retrieved oocytes on univariate analysis. Only the serum AMH level was a significant predictor of poor ovarian response in women with endometriosis. CONCLUSION: Serum AMH may be a better predictor of the ovarian response of COH in patients with endometriosis than basal FSH or age. AMH level can be considered a useful clinical predictor of poor ovarian response in endometriosis patients.