GLDA and EDTA assisted phytoremediation potential of Sedum hybridum 'Immergrunchen' for Cd and Pb contaminated soil.

Exogenous application of chelants is a common way to enhance the phytoextraction of heavy metals. A pot experiment was conducted to investigate the influences of cadmium (Cd), lead (Pb), Cd and Pb, L-glutamic acid N, N-diacetic acid (GLDA) and ethylene diamine tetraacetate (EDTA) on the growth, Cd and Pb accumulation of Sedum hybridum 'Immergrunchen'. The results showed that Sedum hybridum 'Immergrunchen' had a high tolerance to Pb treatment, followed by Cd-Pb treatment. The plant was sensitive to Cd stress. EDTA treatment was more harmful to plant growth than that of GLDA treatment. The optimal Cd concentration of shoot and root reached 27.6 mg·kg-1 and 32.6 mg·kg-1, 757 mg·kg-1 and 1,025 mg·kg-1for Pb accumulation at 100-1,500 mg·kg-1. The maximum Cd and Pb phytoextraction from 3 mmol·kg-1 GLDA treatment were 1.40 and 1.73 times as much as that of the control, 1.21 and 1.02 times under 6 mmol·kg-1 EDTA treatment. Therefore, the enhanced phytoremediation of GLDA to Cd and Pb co-contaminated soil was better than that of EDTA. GLDA-assisted phytoextraction of Cd and Pb by Sedum hybridum 'Immergrunchen' can be considered as a promising way to phytoremediate Cd and Pb co-contaminated soil.

Sedum hybridum 'Immergrunchen', characterized by strong resistance to waterlogging, draught, salt and zinc, high propagating rate, long green period and high ornamental value, was used as the experimental material. Here, we investigated the best phytoremediation effect of Sedum hybridum 'Immergrunchen' to Cd-Pb stress, GLDA and EDTA assisted phytoremediation potential of Sedum hybridum 'Immergrunchen' for Cd and Pb contaminated soil under the best phytoremediation concentration. The results indicated that Cd and Pb phytoextraction under 3 mmol·kg⁻¹GLDA treatment increased by 39.8% and 73.4% compared with the control, while increased by 21.0% and 1.80% under 6 mmol·kg⁻¹EDTA. More importantly, Pb concentration of shoot in Sedum hybridum 'Immergrunchen' reached the criteria of hyperaccumulators under 3 mmol·kg⁻¹ GLDA treatment.

A Noncovalent π-Stacked Porous Organic Molecular Framework for Selective Separation of Aromatics and Cyclic Aliphatics.

Selective separation using porous adsorbents is an energy-efficient alternative to traditional separation techniques. Stacked porous organic molecular frameworks (POMFs) capable of noncovalent π⋅⋅⋅π interactions are emerging as a new kind of adsorbents that facilitate green separation. Here we report a robust porous molecular crystal (TAPM-1), which is stabilized by multiple intermolecular π⋅⋅⋅π interactions. With its long-range π-stacking, TAPM-1 has excellent hydrophobicity, thermostability, recyclability, and high selectivity for aromatics over the corresponding cyclic aliphatics. This enables TAPM-1 to serve as the stationary phase in the high-resolution gas chromatographic separation of benzene and cyclohexane or toluene and methylcyclohexane.

Bisphenol A stimulates steroidogenic acute regulatory protein expression via an unknown mechanism in adrenal cortical cells.

Bisphenol A (BPA) is one of the most widespread endocrine disrupting chemicals in the environment. Exposure to BPA is known to be associated with disruption of steroidogenesis in reproductive tissues, but little is known about its effects on the adrenal gland. We previously showed that prenatal BPA exposure resulted in elevated plasma corticosterone levels concomitant with increased adrenal levels of steroidogenic acute regulatory protein (StAR), the rate-limiting step in steroidogenesis, in adult female mouse offspring. However, the molecular mechanisms underlying the BPA-induced StAR protein expression in the adrenal gland remain unknown. Therefore, the current study was designed to address this important question using the human cortical cell line, H295A cells, as an in vitro model system. We found that: (1) BPA increased StAR protein levels in a dose-dependent manner; (2) both estrogen receptor alpha (ERα)- and ERß-specific agonists mimicked while the ER antagonist ICI abrogated the stimulatory effects of BPA on StAR protein levels; and (3) BPA did not alter StAR messenger RNA, 37kDa preprotein or protein half-life. Taken together, these findings demonstrate that BPA increases StAR protein levels through an unknown mechanism independent of StAR gene transcription, translation, and protein half-life. Furthermore, such effects are likely mediated by ERα and/or ERß.

Synthesis and characterization of π-extended "earring" subporphyrins.

A π-extended "earring" subporphyrin 3 was synthesized from ß,ß'-diiodosubporphyrin and diboryltripyrrane via a Suzuki-Miyaura coupling and following oxidation. Its Pd complex 3Pd was also synthesized and both of the compounds were fully characterized by 1H NMR, MS and X-ray single crystal diffraction. The 1H NMR spectra and single crystal structures revealed that aromatic ring current did not extend to the "ear" in both of the two compounds. Their UV-vis/NIR spectra were recorded and the absorption of both compounds is extended to the NIR region and that the absorption of 3Pd is further red-shifted and more intense.

Bisphenol A suppresses glucocorticoid target gene (ENaCγ) expression via a novel ERß/NF-κB/GR signalling pathway in lung epithelial cells.

We previously demonstrated that prenatal exposure to Bisphenol A (BPA) disrupts fetal lung maturation likely through the glucocorticoid signalling pathway, but the precise molecular mechanisms remain obscure. Given that BPA diminished the expression of epithelial sodium channel-γ (ENaCγ), a well-known glucocorticoid receptor (GR) target gene, in fetal lungs, we used this GR target gene to delineate the molecular pathway through which BPA exerts its effects on lung cells. The A549 lung epithelial cell line was used as an in vitro model system. As a first step, we validated our in vitro cell model by demonstrating a robust concentration-dependent suppression of ENaCγ expression following BPA exposure. We also showed that both dexamethasone and siRNA-mediated knockdown of GR expression blocked/abrogated the inhibitory effects of BPA on ENaCγ expression, suggesting that BPA repressed ENaCγ expression via inhibition of GR activity. Given the well-known antagonistic interactions between the pro-inflammatory transcriptional factor NF-κB and GR, we then showed that BPA inhibited GR activity through the activation of NF-κB. Lastly, since BPA is known to function as a pro-inflammatory factor via the estrogen receptor ß (ERß), we provided evidence that BPA signals through ERß to activate the NF-κB signalling pathway. Taken together, these findings demonstrate that BPA acts on ERß to activate the NF-κB signalling pathway, which in turn leads to diminished GR activity and consequent repression of ENaCγ expression in lung epithelial cells. Thus, our present study reveals a novel BPA signalling pathway that involves ERß, NF-κB and GR.

Prenatal Exposure to Bisphenol A Disrupts Mouse Fetal Liver Maturation in a Sex-Specific Manner.

Bisphenol A (BPA) is one of the most prevalent endocrine disrupting chemicals in the environment. Developmental exposure to BPA is known to be associated with liver dysfunction and diseases, such as hepatic steatosis, liver tumors, metabolic syndrome, and altered hepatic gene expression, and DNA methylation profiles. However, the effects of BPA on rodent liver development are unknown. The present study was undertaken to address this important question using the mouse as an experimental model. Pregnant mice were exposed to BPA via diet from embryonic day 7.5 (E7.5) to E18.5. At E18.5, fetal livers were collected, and analyzed for changes in the expression of key hepatocyte maturation markers. We found the following significant alterations in BPA-exposed female but not male fetal livers: (a) levels of the mature hepatocyte markers, albumin and glycogen synthase proteins, were decreased (-65% and -40%, respectively); (b) levels of the immature hepatocyte marker, α-fetoprotein, were increased (+43%); (c) the level of C/EBP-α protein, the master transcription factor essential for hepatocyte maturation, was down-regulated (-50%); and (d) the level of PCNA protein (marker of proliferation) was elevated (+40%), while that of caspase-3 protein and activity (markers of apoptosis) was reduced (-40% and -55%, respectively), suggestive of a perturbed balance between cell proliferation and apoptosis in BPA-exposed female fetuses. Taken together, these findings demonstrate that prenatal exposure to BPA disrupts the mouse fetal liver maturation in a sex-specific manner, and suggest a fetal origin for BPA-induced hepatic dysfunction and diseases.

Prenatal exposure to bisphenol A disrupts mouse fetal lung development.

Developmental exposure to bisphenol A (BPA) is associated with lung dysfunction and diseases. However, it is unknown if this association has a fetal origin. The present study addressed this important question by examining the effects of BPA on fetal lung development. BPA was administered to pregnant mice via diet from embryonic day (E) 7.5 to E18.5. Fetal lungs were analyzed at E18.5 for changes in structure and expression of key molecular markers of lung maturation. Our main findings were as follows: BPA severely retards fetal lung maturation, as evidenced by diminished alveolar airspace (15% of control) and thickened septa, hallmarks of lung immaturity; this immaturity is characterized by aberrant alveolar epithelial type I cell differentiation because expression of the type I cell marker, aquaporin 5, but not type II cell markers, is dramatically reduced (16% of control); and the effects of BPA are likely mediated through the glucocorticoid signaling pathway because the expression of epithelial sodium channel γ and glutathione peroxidase, 2 well-known glucocorticoid target genes, is down-regulated in BPA-exposed fetal lungs, and, importantly, maternal dexamethasone administration rescues the lung immaturity phenotype. Taken together, these findings demonstrate that BPA disrupts fetal lung maturation, thus suggesting a fetal origin for BPA-induced lung diseases.

Metallothionein-I- and -II-deficient mice display increased susceptibility to cadmium-induced fetal growth restriction.

Maternal cadmium exposure induces fetal growth restriction (FGR), but the underlying mechanisms remain largely unknown. The placenta is the main organ known to protect the fetus from environmental toxins such as cadmium. In this study, we examine the role of the two key placental factors in cadmium-induced FGR. The first is placental enzyme 11ß-hydroxysteroid dehydrogenase type 2 (11ß-HSD2), which is known to protect the fetus from exposure to high cortisol levels and subsequently FGR, and the second the cadmium binding/sequestering proteins metallotheionein (MT)-I and -II. Using the MT-I/II(-/-) mouse model, pregnant mice were administered cadmium, following which pups and placentas were collected and examined. MT-I/II(-/-) pups exposed to cadmium were significantly growth restricted, but neither placental weight nor 11ß-HSD2 was altered. Although cadmium administration did not result in any visible structural changes in the placenta, increased apoptosis was detected in MT-I/II(-/-) placentas following cadmium exposure, with a significant increase in levels of both p53 and caspase 3 proteins. Additionally, glucose transporter (GLUT1) was significantly reduced in MT-I/II(-/-) placentas of pups exposed to cadmium, whereas zinc transporter (ZnT-1) remained unaltered. Taken together, these results demonstrate that MT-I/II(-/-) mice are more vulnerable to cadmium-induced FGR. The present data also suggest that increased apoptosis and reduced GLUT1 expression in the placenta contribute to the molecular mechanisms underlying cadmium-induced FGR.

The ERK1/2 signaling pathway regulates 11beta-hydroxysteroid dehydrogenase type 2 expression in human trophoblast cells through a transcriptional mechanism.

The placental 11beta-hydroxysteroid dehydrogenase type 2 (11beta-HSD2; encoded by the HSD11B2 gene) plays a key role in fetal development, but its regulation is incompletely understood. We previously demonstrated that p38 MAPK was a positive regulator of placental 11beta-HSD2. However, it remains unknown if the other two MAPKs, ERK1/2 and JNK, were also involved. In the present study, we identified ERK1/2 as an important regulator of placental 11beta-HSD2. We showed that inhibition of ERK1/2 with the pharmacological inhibitor U0126 led to a 3-fold increase in 11beta-HSD2 activity, protein, and mRNA in primary human placental trophoblast cells. In contrast, the JNK inhibitor SP600125 had no effect. Furthermore, U0126 increased the HSD11B2 promoter activity by 300%, indicating that ERK1/2 regulates placental 11beta-HSD2 expression through a transcriptional mechanism. Importantly, siRNA-mediated knockdown of ERK1/2 caused a similar increase in 11beta-HSD2 protein. In addition, given that we previously showed that cadmium reduced placental 11beta-HSD2 expression via a transcriptional mechanism, but the signal transduction pathways involved remain unclear, we also addressed this question and found that treatment of trophoblast cells with cadmium led to rapid activation of ERK1/2. Importantly, U0126 completely abrogated the inhibitory effects of cadmium on placental 11beta-HSD2. Taken together, the present study not only identifies the ERK1/2 signaling pathway as a potent negative regulator of placental 11beta-HSD2 but also demonstrates that this pathway mediates cadmium repression of placental 11beta-HSD2. Thus, our present study reveals 11beta-HSD2 as an important target through which ERK1/2 may regulate human placental function and consequently fetal development.

Purification and Characterization of a Dark Red Skin Related Dimeric Polyphenol Oxidase from Huaniu Apples.

The distinct dark-red skin of Huaniu apples renders them attractive to customers. However, the mechanism that leads to the development of the color of the fruit is unclear. In this study, we found that compared with red Fuji (a bright-red apple cultivar), Huaniu apples had higher contents of (-)-epicatechin (EC), (-)-epigallocatechin (EGC), (-)-gallocatechin gallate (GCG), and procyanidins (PCs) B2 and C1 in the peel, which implies that the polymerization of the flavanols and PCs may be correlated with the dark-red skin of the fruit. Using EC as a substrate, we purified an enzyme from Huaniu peel. We performed protein sequencing and discovered that the enzyme was a polyphenol oxidase (PPO). The molecular weight of the enzyme was approximately 140 kDa, which we estimated by native-PAGE and SDS-PAGE, while it was 61 kDa by urea-SDS-PAGE, from which we discovered that the PPO was a dimer. We observed the lowest Km value for catechol (0.60 mM), and the best substrate was 4-methylcatechol, with a Vmax of 526.32 U mg-1 protein. EC is a suitable natural substrate, with a Km value of 1.17 mM, and 55.27% of the Vmax/Km of 4-methylcatechol. When we used EC as a substrate, the optimum temperature and pH of the PPO were 25 °C and 5.0, respectively. In summary, we purified a dimeric PPO from Huaniu apples that showed high activity to EC, which might catalyze the polymerization of flavanols and PCs and lead to the dark-red color development of the fruit.

BMP-3 promotes mesenchymal stem cell proliferation through the TGF-beta/activin signaling pathway.

Adipogenesis plays a key role in the pathogenesis of obesity. It begins with the commitment of mesenchymal stem cells (MSCs) to the adipocyte lineage, followed by terminal differentiation of preadipocytes to mature adipocytes. A critical, but poorly understood, component of adipogenesis involves proliferation of MSCs and preadipocytes. The present study was undertaken to examine the hypothesis that bone morphogenetic protein-3 (BMP-3) promotes adipogenesis using C3H10T1/2 MSCs and 3T3-L1 preadipocytes as in vitro model systems. We demonstrated that although it did not promote the commitment of MSCs to the adipocyte lineage or the differentiation of preadipocytes to adipocytes, BMP-3-stimulated proliferation by threefold in both cell types. Owing to a lack of information on MSC proliferation, we then delineated the molecular mechanisms underlying BMP-3-stimulated MSC proliferation. We showed that BMP-3 activated the transforming growth factor-beta (TGF-beta)/activin but not ERK1/2, p38 MAPK, or JNK signaling pathways in C3H10T1/2 cells. Furthermore, the TGF-beta/activin receptor kinase inhibitor SB-431542 blocked BMP-3-stimulated proliferation. Importantly, siRNA-mediated knockdown of the key TGF-beta/activin signaling pathway components, ActRIIB, ALK4, or Smad2, abrogated the mitogenic effects of BMP-3 on MSCs. Together, these results demonstrate that BMP-3 stimulates MSC proliferation via the TGF-beta/activin signaling pathway, thus revealing a novel role for this divergent and poorly understood member of the TGF-beta superfamily in regulating MSC proliferation.

Keratinocyte growth factor promotes preadipocyte proliferation via an autocrine mechanism.

Keratinocyte growth factor (KGF; also known as FGF-7) is a well-characterized paracrine growth factor for tissue growth and regeneration. However, its role in adipose tissue, which is known to undergo tremendous expansion in obesity, is virtually unknown. Given that we previously identified KGF as one of the up-regulated growth factors in adipose tissue of an early-life programmed rat model of visceral obesity, the present study was undertaken to examine the hypothesis that KGF promotes adipogenesis. Using 3T3-L1 and rat primary preadipocytes as in vitro model systems, we demonstrated that (1) KGF stimulated preadipocyte proliferation in a concentration-dependent manner with a maximal effect at 2.5 ng/ml (approximately 2-fold increase); (2) KGF mRNA was highly expressed in rat adipocytes and preadipocytes as well as 3T3-L1 cells; (3) treatment of preadipocytes with a neutralizing antibody against KGF and siRNA-mediated knockdown of KGF led to a 50% reduction in their proliferative capacity; (4) KGF activated the protein kinase Akt, and the PI3 kinase inhibitor LY294002 blocked KGF stimulation of preadipocyte proliferation; and (5) KGF did not promote differentiation of preadipocytes to mature adipocytes. Together, these results reveal adipocytes and their precursor cells as novel sites of KGF production. Importantly, they also demonstrate that KGF promotes preadipocyte proliferation by an autocrine mechanism that involves activation of the PI3K/Akt signaling pathway. Aberrant KGF expression may have consequences not only for normal adipose tissue growth but also for the pathogenesis of obesity.

Neuropeptide Y is produced in visceral adipose tissue and promotes proliferation of adipocyte precursor cells via the Y1 receptor.

Neuropeptide Y (NPY) is synthesized in neural tissue of the central and peripheral nervous systems and has a number of important functions besides regulating appetite and energy homeostasis. Here we identify a novel site of NPY biosynthesis and a role for NPY in promoting proliferation of adipocyte precursor cells. We show that NPY mRNA is not only expressed in visceral adipose tissue (VAT) but that its levels are up-regulated 6-fold in our early-life programmed rat model of increased visceral adiposity. This is accompanied by a parallel rise in NPY protein, demonstrating that VAT is a novel peripheral site of NPY biosynthesis. Furthermore, NPY mRNA expression is also elevated >2-fold in VAT of obese Zucker rats. Importantly, NPY stimulates proliferation of primary rat preadipocytes as well as 3T3-L1 preadipocytes in vitro. This mitogenic effect appears to be mediated by the Y1 receptor and involves the activation of extracellular related kinase 1/2. In addition, insulin and glucocorticoid up-regulate VAT NPY expression in lean but not obese Zucker rats. Taken together, these results suggest that an enhanced local expression of NPY within VAT may be a common feature of and contribute to the molecular mechanisms underlying increased visceral adiposity.

Insulin and dexamethasone dynamically regulate adipocyte 11beta-hydroxysteroid dehydrogenase type 1.

The adipocyte enzyme 11beta-hydroxysteroid dehydrogenase type 1 (11beta-HSD1) amplifies local glucocorticoid action by generating active glucocorticoids from inactive metabolites and has emerged as a key player in the pathogenesis of central obesity and metabolic syndrome. However, the regulation of adipocyte 11beta-HSD1 is incompletely understood. Therefore, the present study was designed to investigate the effects of insulin and glucocorticoid as well as their underlying molecular mechanisms on 11beta-HSD1 activity and expression in 3T3-L1 adipocytes and determine whether the in vitro findings could be confirmed in vivo. Our main in vitro findings are 1) insulin stimulated whereas dexamethasone inhibited 11beta-HSD1 activity and expression in a time- and concentration-dependent manner; 2) the effect of dexamethasone was mimicked by both cortisol and corticosterone but blocked by the glucocorticoid receptor antagonist RU486; 3) the p38 MAPK inhibitor SB220025, but not the ERK inhibitor U0126 or the phosphatidylinositol 3-kinase inhibitor LY294002, prevented insulin stimulation of 11beta-HSD1 activity; and 4) although dexamethasone did not alter the half-life of 11beta-HSD1 mRNA, insulin doubled it. Taken together, these in vitro results demonstrate that insulin stimulates adipocyte 11beta-HSD1 through a posttranscriptional mechanism that involves activation of the p38 MAPK signaling pathway, whereas dexamethasone exerts an opposite effect by a glucocorticoid receptor-mediated transcriptional mechanism. In contrast, both insulin and dexamethasone augmented 11beta-HSD1 activity and expression in rat white adipose tissue in vivo, thus confirming the role of insulin but revealing a fundamental difference regarding the role of dexamethasone in regulating adipocyte 11beta-HSD1 between the two model systems.

RNA isolation and real-time quantitative RT-PCR.

Adipose tissue has emerged as a major endocrine organ producing a wide spectrum of hormones and factors that play crucial roles in regulating cell turnover and function, not only locally within the adipose tissue but also in the brain and other key metabolic organ systems. It is known that gene activity is controlled at both transcriptional and post-transcriptional levels. Consequently, one of the most important means by which the activity of a gene is assessed is through the determination of levels of the corresponding messenger ribonucleic acid (mRNA). This process involves the isolation of total cellular RNA and subsequent analysis of the mRNA of interest. Given the unique nature of adipose tissue and adipocytes (i.e., containing high amounts of lipid), special RNA isolation techniques that have been tested in both white adipose tissue and isolated mature adipocytes from rats and mice will be presented. Although several methods are available for mRNA quantitation, we will describe a real-time quantitative reverse transcription polymerase chain reaction protocol because of its superior sensitivity and reliability.

Bisphenol A stimulates adrenal cortical cell proliferation via ERß-mediated activation of the sonic hedgehog signalling pathway.

We previously demonstrated that prenatal exposure to bisphenol A (BPA) resulted in increased adrenal gland weight independent of changes in plasma ACTH levels in adult mouse offspring. This finding suggested that BPA exposure likely had a direct effect on adrenal development. Given that (1) sonic hedgehog (Shh) signaling is essential for adrenal development; (2) deletion of the Shh gene in mice results in adrenal hypoplasia; (3) BPA is known to signal through estrogen receptor ß (ERß); and (4) ERß is highly expressed in adrenal glands; we hypothesized that BPA stimulates adrenal cell proliferation via ERß-mediated activation of the Shh pathway. To test this hypothesis, the human adrenal cell line, H295A cells, was used as an in vitro model system. Our main findings were: (1) BPA increased cell number and protein levels of proliferating cell nuclear antigen (PCNA; a universal marker of cell proliferation), cyclin D1 and D2 (key proliferation factors), as well as Shh and its key transcriptional regulator Gli1; (2) cyclopamine, a Shh pathway inhibitor, blocked these stimulatory effects of BPA on cell proliferation; (3) BPA increased the nuclear translocation of ERß; and (4) the ERß-specific agonist DPN mimicked while the ERß-specific antagonist PHTPP abrogated the stimulatory effects of BPA on cell proliferation and Shh signaling. Taken together, these findings demonstrate that BPA stimulates adrenal cell proliferation likely through ERß-mediated activation of the Shh signaling pathway. Thus, the present study provides novel insights into the molecular mechanisms underlying our previously reported BPA-induced aberrant adrenal phenotype.

Prevention of chronic renal allograft rejection by SERP-1 protein.

BACKGROUND: In previous studies we have demonstrated that Serp-1, a myxoma virus encoded serine protease inhibitor, dramatically inhibits neointimal hyperplasia in vascular injury and aortic transplant models. Here we examined the effect of peritransplant Serp-1 administration on chronic renal allograft rejection. METHODS: Rat renal transplants were performed with sequential recipient sacrifice on postoperative days 2, 10 and 140 to examine both the acute and chronic effects of Serp-1 in recipient rats. RESULTS: Serp-1 administration reduced early posttransplant injury (POD 2) with less acute tubular and vascular necrosis. This translated into a reduction of the characteristic late stage changes of chronic rejection (POD 140), with significantly decreased glomerulosclerosis and neointimal hyperplasia. Effects of Serp-1 treatment were already evident as early as POD 2 with markedly decreased levels of TGF-beta mRNA witnessed at both the early and late time points (POD 2, 10 and 140). CONCLUSION: We have demonstrated that peritransplant Serp-1 viral protein decreased early injury and allowed reduced chronic rejection in a rat renal model. Recipients treated with Serp-1 are associated with a decrease in TGF-beta mRNA levels in the allografts suggesting that the serine protease inhibitor may inhibit TGF-beta transcription and its profibrotic effects.

Prenatal exposure to bisphenol A disrupts adrenal steroidogenesis in adult mouse offspring.

The present study sought to determine if prenatal exposure to bisphenol A (BPA) alters adrenal steroidogenesis in adult offspring. Pregnant mice were exposed to BPA (25mg BPA/kg food pellet) via diet from day 7 to the end of pregnancy. At eight weeks of age, offsprings were sacrificed, blood samples and adrenal glands were collected for hormone assays and western blot analysis, respectively. We found that: (1) BPA increased adrenal gland weight in both males and females; (2) although BPA elevated plasma corticosterone levels in both sexes, it stimulated the expression of StAR and cyp11A1, the two rate-limiting factors in the steroidogenic pathway, only in female adrenal glands; and interestingly (3) BPA did not alter plasma ACTH levels or adrenal expression of the key steroidogenic transcription factor SF-1 in either sex. Taken together, the present study provides novel insights into the long-term consequences of developmental BPA exposure on adrenal steroidogenesis.

Wisp1 mediates Bmp3-stimulated mesenchymal stem cell proliferation.

Adipose tissue expansion, resulting from adipocyte hyperplasia and/or hypertrophy, is a hallmark of obesity. Adipocytes are derived from mesenchymal stem cells (MSCs) through adipogenesis, a process involving three key steps: proliferation, commitment and differentiation. Although studies have elaborated on the mechanisms regulating adipocyte commitment and differentiation, the factors that control MSC proliferation remain largely unknown. Previously, we demonstrated that bone morphogenetic protein 3 (Bmp3), the expression of which was upregulated in our rat model of hyperplasic visceral adiposity, potently stimulated MSC proliferation. In the present study, we investigate the molecular target of Bmp3. We conducted DNA microarray analysis on MSCs treated with and without Bmp3 and identified WNT1-inducible signaling pathway protein 1 (Wisp1) as a differentially expressed gene, whose expression was upregulated 3.7-fold by Bmp3. Wisp1 is a proliferative agent in various non-adipose cell types and is implicated in adipogenesis. Therefore, we tested the hypothesis that Wisp1 mediates Bmp3 stimulation of MSC proliferation. We showed that Bmp3 increased the expression of Wisp1 as early as 3 h following Bmp3 treatment in MSCs. Importantly, the upregulated Wisp1 expression preceded Bmp3-induced MSC proliferation, as determined by [(3)H]-thymidine incorporation. Furthermore, treatment of MSCs with recombinant Wisp1 led to a concentration-dependent increase in [(3)H]-thymidine incorporation with a maximal increase of 300%. In addition, siRNA-mediated knockdown of Wisp1 expression attenuated Bmp3-induced MSC proliferation. Taken together, our present findings reveal Wisp1 as a novel target of Bmp3 and suggest that the Bmp3/Wisp1 signaling pathway play a key role in MSC proliferation, and consequently adipogenesis.

Prenatal exposure to bisphenol A alters mouse fetal pancreatic morphology and islet composition.

BACKGROUND: Exposure to bisphenol A (BPA), an endocrine disrupting chemical, during gestation is associated with a variety of metabolic dysfunctions in adulthood, including hyperinsulinemia, glucose intolerance and insulin resistance. These modifications in glucose homeostasis largely stem from alterations in pancreatic function. However, the effects of BPA on the fetal pancreas have never been explored. The present study addressed this important question by examining the effects of prenatal BPA exposure on the mouse fetal pancreatic development. MATERIALS AND METHODS: Pregnant mice were fed a BPA diet (25 mg BPA/kg diet) from embryonic day 7.5 (E7.5) to E18.5. At E18.5, fetal pancreata were collected and analyzed for morphological changes in the endocrine pancreas such as islet size, number and ß and α cell distribution. RESULTS: We showed that BPA exposed fetal pancreata had a greater number of islet-cell clusters (ICCs; <300 µm(2); p<0.05) compared with controls. Furthermore, immunohistochemical analysis revealed that prenatal BPA exposure increased both glucagon expression in islets and the numbers of glucagon-expressing islet-cell clusters (p<0.05). CONCLUSION: Considering that ICCs represent the initial stages of islet development in the fetal pancreas, our findings suggest that BPA promotes islet differentiation or delays the conversion of ICCs into mature islets. Moreover, the increase in glucagon expression suggests a potential alteration in the α:ß-cell ratio in islets, which may have significant implications for the fetal pancreas both structurally and functionally. This study provides novel insight into the effects of BPA exposure on the fetal pancreata, indicating alterations in glucagon expression in islets and ICCs.