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Rapamycin is an immunosuppressant that inhibits the mammalian or mechanistic target of rapamycin (mTOR) protein kinase and extends lifespan in organisms including mice. Myf5 and MyoD act as muscle-specific transcriptional factors for skeletal muscle differentiation. In this study, we determined whether rapamycin-induced autophagy causes the decrease of Myf5 and MyoD protein in C2C12 myoblast cells. Rapamycin induced a significant increase in the expression of the microtubule-associated protein 1 light chain 3 (LC3) II protein in a dose-dependent manner for 12 h. Rapamycin treatment also significantly increased p-ERK, p-Akt, and catalase expressions, and decreased Mn-SOD expression in a dose-dependent manner. Bax expression was significantly high compared to Bcl-2 expression in a dose-dependent manner of rapamycin for 12 h. For further study of rapamycin-induced autophagy in C2C12 myoblast cells, we investigated rapamycin treatment for 24, 36, and 48 h. Cell viability did not change with rapamycin treatment for 24, 36, and 48 h. Rapamycin-induced LC3-II, Beclin-1, Bax, and Bcl-2 proteins were significantly increased compared to without rapamycin. p-ERK expression increased with rapamycin treatment for 24 and 36 h compared to that without rapamycin, but decreased for 48 h. p-Akt expression decreased with rapamycin treatment for 36 and 48 h compared to that without rapamycin. In the same conditions, rapamycin-induced autophagy significantly reduced the Myf5 and MyoD proteins. Together, these results suggest that rapamycin-induced autophagy results in the decrease of Myf5 and MyoD proteins in C2C12 myoblast cells.

The embryoid body test (EBT) is a developmental toxicity test method that assesses the half inhibitory concentrations of substances in the area of embryoid bodies (EBs), and in the viability of mouse embryonic stem cells (ESCs) and fibroblasts (3T3 cells) following chemical exposure for three and four days, respectively. In the previous study, the EBT showed more advanced than the embryonic stem cell test (EST) from the European Centre for the Validation of Alternative Methods (ECVAM) applying cardiac differentiation of mouse ESCs, because the EBT greatly reduced the exposure time, labor, and amount of materials required, and misclassification of embryotoxic potential. This pre-validation study evaluated the predictive accuracy of the EBT using 26 coded test substances by two steps: intra-laboratory and inter-laboratory reproducibility tests. Since some substances have different embryotoxic potentials at different pregnancy periods, in this study, a new prediction model consisting of non-toxic and toxic classes was used, instead of the existing prediction model assessing embryotoxicants in four classes. The results of the intra- and inter-laboratory tests were highly accurate (above 80%) when substances were classified using the predictive model. In conclusion, EBT can accurately classify various embryotoxicants in a short time with less effort and greater validation.

In pancreatic β cells, which produce and secrete insulin, Ca2+ signals contribute to insulin production and secretion. Bisphenol A (BPA) and octylphenol (OP) are reported to increase plasma insulin levels and insulin transcription factors, but regulation of plasma glucose levels did not decrease proportionally to the insulin increase. We hypothesized that BPA and OP disrupt calcium homeostasis resulting in insulin resistance through induction of endoplasmic reticulum (ER) stress. BPA and OP treatment leads to survival of pancreatic β cells against streptozotocin, but despite an increased insulin level, serum glucose regulation is not properly regulated. The expression of genes involved in transporting calcium ions to the cytosol and ER decreased while the expression of those affecting the removal of calcium from the cytosol and ER increased. Depletion of calcium from the ER leads to ER stress and can induce insulin resistance. Insulin resistance is also confirmed by insulin-responsive gene, such as glucose transporter 4 (GLUT4) and IRS2, expression. Taken together, these results imply that disruption of calcium homeostasis by BPA and OP induces ER stress and leads to insulin resistance, especially in a streptozotocin (STZ) -induced type 1 diabetes mellitus model.

Autophagy is a highly regulated physiologic mechanism in which cells maintain homeostasis by degrading excessive or unnecessary proteins and damaged or aged organelles through the lysosomal machinery (Yorimitsu and Klionsky, 2005) [1]. MyoD is basic helix-loop-helix (bHLH) transcription factors that regulate myoblast proliferation and myogenic differentiation. MyoD is expressed in adult skeletal muscle (Megeney et al., 1996) [2] and adult fibers (Brack et al., 2005) [3]. MyoD is mainly degraded by the ubiquitin-proteasome system (Floyd et al., 2001) [4] and partly by autophagy (Kim et al., 2012) [5]. Data showed that autophagy decreased MyoD protein in C2C12 cells by Western blotting analysis. Keywords: MyoD, Degradation, Autophagy, C2C12 cells

To secure the safety for industrial applications of plant essential oils, it is necessary to determine the inhibitory concentration and inhibitory mechanism of cell proliferation in skin cells and lung cells. Considering inhalation through the respiratory system and skin contact of humans with essential oils, we used human lung cancer cells A549 and human skin fibroblasts Detroit 551 cells for all experiments. In this study, we examined IC50 values and protein levels of cell cycle markers (cyclin A, cyclin B, cyclin D, and cyclin E) and apoptosis marker (caspase-3) after exposure to 10 plant essential oils, including Dendranthema indicum (L.) Des Moul, Peucedanum japonicum Thunb, Dendranthema zawadskii var. latilobum (Maxim.) Kitam, Agastache rugosa (Fisch.&Mey.) Kuntze, Vitex rotundifolia L.f, Pinus rigida Mill; Orixa japonica Thunb, Pinus strobus L, Chamaecyparis pisifera (Siebold et Zucc.) Endl. var. filifera Beissn. et Hochst, and Citrus sunki Hort. ex Tanaka. After the treatment of A549 and Detroit 551 cells to varying concentrations of the 10 plant essential oils, IC50 values were determined by CCK analysis, whereas protein expressions of the four cyclins and caspase-3 were identified by Western blotting analysis. We believe that by examining the degree and mechanism of cell proliferation inhibition exerted by essential oils on skin and lung cells of humans, data obtained in this study can provide guidelines for the industrial application of plant essential oils.

Composites consisting of bacterial cellulose (BC) and ionic conducting polymer (ICP) were prepared. BC was biosynthesized in media at 0, 25, 50 and 100 rpm. ICP was chemically synthesized at different concentrations of ionic salt. The corresponding electrical conductivity of the composites was measured as a function of ionic salt concentration. ICP improved the optical transparency and electrical conductivity of the BC/ICP composites. Morphological images of BC/ICP composites showed that the pore size of the BC pellicle increased while the diameter and density of the BC fibers decreased. The cultivation method was critical in affecting the structure and electrical conductivity of the composites.

Aims Parathyroid hormone-related protein (PTHrP) is a peptide growth factor produced in a wide range of tissues from brain and parathyroid, to kidney and uterus. The purpose of this study was to determine whether the adrenal cortical hormones, hydrocortisone (cortisol), modulate PTHrP expression and glucocorticoid receptor (GR)β in mice kidney. Main methods Changes in PTHrP gene expression were determined by real-time PCR and its protein level was examined by Western blot analysis. In addition, expression of renal PTHrP protein was localized by immunohistochemistry. Effects of RU486 on the expression levels of GRα/β or PTHrP gene in the kidneys were analyzed by Western blot analysis. Key findings We found that renal expression levels of PTHrP mRNA were higher in males than in females up to 9 weeks of age. Using immunohistochemistry, we observed higher levels of PTHrP expression within the cortex than in the medulla in both male and female mice, and this expression was localized in the epithelial cells of the renal proximal tubules. Treatment of 4-week-old mice with aldosterone and cortisol for three days showed larger increases in both PTHrP mRNA and protein levels in males compared with females. The expression of GRβ in male, but not female, kidneys was significantly upregulated after treatment with cortisol, but not after treatment with aldosterone. Inhibition of glucocorticoid signaling by pre-treatment with a GR antagonist prior to cortisol administration largely abolished this cortisol-dependent increase in PTHrP and GRβ expressions. Significance These results suggest that PTHrP expression and GRβ in the kidneys of male mice may be regulated by cortisol.

Murine embryonic stem (ES) cells constitute a versatile biological system that has facilitated major advances in the fields of cell and developmental biology. Although melatonin has a wide variety of biological functions, its effect on ES cells is still unknown. In this study, we examined the effects of melatonin on transcription factors of ES cells (ES-E14TG2a cells) using an in vitro culture system. We found that melatonin affected cellular proliferation and Akt phosphorylation. Melatonin treatment also increased Bcl-2 expression and suppressed Bax expression and decreased phosphorylation of GSK α/β. The transcription factor Oct4, which contains the POU (N-terminal to homeobox) domain, and the transcription factor Sox2, the zinc finger transcription factor Zfp206, and the zinc finger gene REX-1 (Znf42), which contain the high mobility group (HMG) domain, are all important for cellular pluripotency and pre-implantation development. In this study, melatonin treatment influenced Oct4 and REX-1 expression at day 1 but not significantly at days 2 and 3. In addition, Sox2 and Zfp206 expressions did not change over the course of melatonin treatment. Taken together, melatonin may affect Akt activation but does not influence the mRNA expressions of Oct4, REX-1, Sox2, or Zfp206, suggesting that melatonin may stimulate proliferation of ES-E14TG2a cells via Akt phosphorylation.

In this study, a female pubertal assay on the effects of parabens, including methyl-, ethyl-, propyl-, isopropyl-, butyl-, and isobutylparaben, was performed in a female Sprague-Dawley rat model during the juvenile-peripubertal period. The rats were orally treated with these parabens from postnatal day 21-40 in a dose-dependent manner (62.5, 250 and 1000 mg/kg body weight [BW]/day). 17alpha-Ethinylestradiol (1mg/kg BW/day) was used as a positive control and corn oil as a vehicle. A high dose of methyl- and isopropylparaben (1000 mg/kg BW/day) resulted in a significant delay in the date of vaginal opening and a decrease in length of the estrous cycle. In measurements of organ weight and body weight, we observed significant weight changes in ovaries, adrenal glands, thyroid glands, liver, and kidneys; conversely, body weight was not altered following paraben treatment. The potential effects of parabens on estrogenicity were shown in histopathological abnormities in the reproductive organs. Histological analysis of the ovaries from the peripubertal rats revealed a decrease of corpora lutea, increase in the number of cystic follicles, and thinning of the follicular epithelium. In addition, morphological studies of the uterus revealed the myometrial hypertrophy by a high dose of propyl- and isopropylparaben (1000 mg/kg-day), and in all dose groups of butyl- and isobutylparabens. However, no significant histopathological changes were observed in the other organs (i.e. adrenal and thyroid glands). We also observed a significant decrease in serum estradiol and thyroxine concentrations in methyl-, ethyl-, propyl-, isopropyl-, and isobutylparaben-treated groups. A receptor-binding assay indicated that the relative binding affinities of parabens to estrogen receptors occurred in the order: isobutylparaben>butylparaben>isopropylparaben=propylparaben>ethylparaben. These values were much lower than the binding affinity for 17beta-estradiol. Taken together, long-term exposure to parabens, which show less estrogenic activity than estradiol, can produce suppressive effects on hormonal responsiveness and can disrupt the morphology of reproductive target tissues. In addition, the relation between thyroid weight and thyroid hormone may influence circulating levels of parabens, suggesting the effects of parabens as thyrotoxic during this critical stage of development in female rats.

Plasma membrane sodium/calcium exchangers are an important component of intracellular calcium homeostasis and electrical conduction. A member of the family of potassium-dependent sodium/calcium exchangers, NCKX3 (SLC24A3) plays a critical role in the transport of an intracellular calcium and potassium ion in exchange for four extracellular sodium ions. NCKX3 mRNA transcripts are particularly abundant in brain and smooth muscle, but many other tissues, including uterus, aorta, and intestine, also express NCKX3, albeit at lower levels. In the present study, we examined uterine expression of NCKX3 at the mRNA and protein levels during the estrous cycle in mature female ICR mice in the absence or presence of the sex steroid hormones estrogen (E2) and progesterone (P4). During the estrous cycle in mice, uterine expression of NCKX3 mRNA and protein was elevated at estrus as compared to proestrus and diestrus. To determine the role of sex steroids in the regulation of NCKX3 expression in the uterus, mice were treated with E2 (40 microg/kg body weight), P4 (4 mg/kg body weight) or E2 plus P4 for 3 days. The levels of NCKX3 mRNA in the uterus of mice were significantly reduced by E2 or P4 treatment. Co-treatment with E2 and P4 caused a significant decrease in the transcription of NCKX3 as compared to E2 or P4 alone, but the effect was not synergistic. Using immunohistochemistry, we identified abundant levels of uterine NCKX3 in the cytoplasm of luminal and glandular epithelial cells at estrus. The results of the present study indicate that NCKX3 is abundantly expressed in the uterus and that its expression is regulated by the steroid hormones E2 and P4. Thus, uterine expression of NCKX3 might be involved in reproductive function during the estrous cycle in female mice.