Pectic Oligogalacturonide Facilitates the Synthesis and Activation of Adiponectin to Improve Hepatic Lipid Oxidation.

SCOPE: Adiponectin (ADPN), a kind of adipokines, plays an important role in the regulation of lipid metabolism. The objective of this study is focused on the ADPN to investigate the functional mechanisms of pectin oligosaccharide (POS) from hawthorn fruit in the improvement of hepatic fatty acid oxidation. METHOD AND RESULTS: High-fat fed mice are used in this experiment. POS is administrated with the doses of 0.25, 0.75, and 1.5 g kg-1 diet, respectively. The results demonstrate that gene and protein expressions of ADPN synthesis regulators involved in PKA/ERK/CREB and C/EBPα/PPARγ pathways are upregulated by POS administration. POS also activates the AdiopR1/AMPKα/PGC1 and AdipoR2/PPARα signaling pathways to improve the fatty acid oxidation in the liver, which is further accelerated by the enhancement of mitochondrial functions. CONCLUSION: POS can act as an ADPN activator to improve lipid metabolism, leading it to the applications of biomedical and functional foods for ameliorating chronic liver diseases resulted from a high-energy diet.

Fgf15 Neurons of the Dorsomedial Hypothalamus Control Glucagon Secretion and Hepatic Gluconeogenesis.

The counterregulatory response to hypoglycemia is an essential survival function. It is controlled by an integrated network of glucose-responsive neurons, which trigger endogenous glucose production to restore normoglycemia. The complexity of this glucoregulatory network is, however, only partly characterized. In a genetic screen of a panel of recombinant inbred mice we previously identified Fgf15, expressed in neurons of the dorsomedial hypothalamus (DMH), as a negative regulator of glucagon secretion. Here, we report on the generation of Fgf15CretdTomato mice and their use to further characterize these neurons. We show that they were glutamatergic and comprised glucose-inhibited and glucose-excited neurons. When activated by chemogenetics, Fgf15 neurons prevented the increase in vagal nerve firing and the secretion of glucagon normally triggered by insulin-induced hypoglycemia. On the other hand, they increased the activity of the sympathetic nerve in the basal state and prevented its silencing by glucose overload. Higher sympathetic tone increased hepatic Creb1 phosphorylation, Pck1 mRNA expression, and hepatic glucose production leading to glucose intolerance. Thus, Fgf15 neurons of the DMH participate in the counterregulatory response to hypoglycemia by a direct adrenergic stimulation of hepatic glucose production while suppressing vagally induced glucagon secretion. This study provides new insights into the complex neuronal network that prevents the development of hypoglycemia.

Alpinia oxyphylla-Schisandra chinensis Herb Pair Alleviates Amyloid-ß Induced Cognitive Deficits via PI3K/Akt/Gsk-3ß/CREB Pathway.

Alzheimer's disease (AD), one of the most common neurodegenerative diseases, threatens people's health. Based on the theory of traditional Chinese medicine (TCM) efficacy and treatment theory, we first proposed the Alpinia oxyphylla-Schisandra chinensis herb pair (ASHP) for finding a candidate of AD treatment. This study aimed at exploring the effects of ASHP on improving the cognitive function and neurodegeneration, and revealing the possible mechanism. In this study, an amyloid-ß (Aß) induced AD model was established in mice via intracerebroventricular injection. The Y-maze test and Morris water maze test were carried out to observe the behavioral change of mice, which showed that ASHP significantly ameliorated cognitive impairment. In addition, ASHP reduced amyloid-ß deposition and downregulated the hyperphosphorylation of tau via immunofluorescence assay and western blot analysis, respectively. Subsequently we focused on the PI3K/Akt pathway that is a classical pathway related to nervous system diseases. It also noticeably ASHP improved the histopathological changes in the hippocampus and cortex. Moreover, it was found that ASHP could upregulate the PI3K/Akt/Gsk-3ß/CREB signaling pathway in N2a-SwedAPP cells. Taken together, it suggests that ASHP might reverse cognitive deficits and neurodegeneration via PI3K/Akt/Gsk-3ß/CREB pathway.

Regulation of Atrial Fibrosis by the Bone.

MR (mineralocorticoid receptor) antagonists have been demonstrated to provide beneficial effects on preventing atrial fibrosis. However, the underlying cellular and molecular mechanisms remain unclear. We aim to determine the role of osteoblast MR in atrial fibrosis and to explore the underlying mechanism. Using osteoblast MR knockout mouse in combination with mutant TGF (transforming growth factor)-ß1 transgenic mouse, we demonstrated that MR deficiency in osteoblasts significantly attenuated atrial fibrosis. Mechanistically, MR directly regulated expression of OCN (osteocalcin) in osteoblasts. Both carboxylated and undercarboxylated OCNs (ucOC) were less secreted in osteoblast MR knockout mice. Mutant TGF-ß1 transgenic mice supplemented with recombinant ucOC showed aggravated atrial fibrosis. In cultured atrial fibroblasts, ucOC treatment promoted proliferation and migration of atrial fibroblasts, whereas cotreatment with an antagonist for a GPRC6A (G-protein-coupled receptor, family C, group 6, member A) abolished these effects. Western blotting analysis revealed upregulation of PKA (protein kinase A) and CREB (cAMP-response element-binding protein) phosphorylation after ucOC treatment. Inhibition of PKA with its antagonist reduced ucOC-induced proliferation and migration of atrial fibroblasts. Finally, the impact of osteoblast MR deficiency on atrial fibrosis was abolished by ucOC administration in mutant TGF-ß1 transgenic mice. Taken together, MR deficiency in osteoblasts attenuated atrial fibrosis by downregulation of OCN to promote proliferation and migration of atrial fibroblasts.

An Essential Role of cAMP Response Element Binding Protein in Ginsenoside Rg1-Mediated Inhibition of Na+/Glucose Cotransporter 1 Gene Expression.

The Na(+)/glucose cotransporter 1 (SGLT1) is responsible for glucose uptake in intestinal epithelial cells. It has been shown that the intestinal SGLT1 level is significantly increased in diabetic individuals and positively correlated with the pathogenesis of diabetes. The development of targeted therapeutics that can reduce the intestinal SGLT1 expression level is, therefore, important. In this study, we showed that ginsenoside Rg1 effectively decreased intestinal glucose uptake through inhibition of SGLT1 gene expression in vivo and in vitro. Transient transfection analysis of the SGLT1 promoter revealed an essential cAMP response element (CRE) that confers the Rg1-mediated inhibition of SGLT1 gene expression. Chromatin immunoprecipitation assay and targeted CRE-binding protein (CREB) silencing demonstrated that Rg1 reduced the promoter binding of CREB and CREB binding protein associated with an inactivated chromatin status. In addition, further studies showed that the epidermal growth factor receptor (EGFR) signaling pathway also plays an essential role in the inhibitory effect of Rg1; taken together, our study demonstrates the involvement of the EGFR-CREB signaling pathway in the Rg1-mediated downregulation of SGLT1 expression, which offers a potential strategy in the development of antihyperglycemic and antidiabetic treatments.

Protein kinase A-mediated cardioprotection of Tongxinluo relates to the inhibition of myocardial inflammation, apoptosis, and edema in reperfused swine hearts.

BACKGROUND: Our previous studies have demonstrated that Tongxinluo (TXL), a traditional Chinese medicine, can protect hearts against no-reflow and reperfusion injury in a protein kinase A (PKA)-dependent manner. The present study was to investigate whether the PKA-mediated cardioprotection of TXL against no-reflow and reperfusion injury relates to the inhibition of myocardial inflammation, edema, and apoptosis. METHODS: In a 90-minute ischemia and 3-hour reperfusion model, minipigs were randomly assigned to sham, control, TXL (0.05 g/kg, gavaged one hour prior to ischemia), and TXL + H-89 (a PKA inhibitor, intravenously and continuously infused at 1.0 µg/kg per minute) groups. Myocardial no-reflow, necrosis, edema, and apoptosis were determined by pathological and histological studies. Myocardial activity of PKA and myeloperoxidase was measured by colorimetric method. The expression of PKA, phosphorylated cAMP response element-binding protein (p-CREB) (Ser(133)), tumor necrosis factor α (TNF-α), P-selectin, apoptotic proteins, and aquaporins was detected by Western blotting analysis. RESULTS: TXL decreased the no-reflow area by 37.4% and reduced the infarct size by 27.0% (P < 0.05). TXL pretreatment increased the PKA activity and the expression of Ser(133) p-CREB in the reflow and no-reflow myocardium (P < 0.05). TXL inhibited the ischemia-reperfusion-induced elevation of myeloperoxidase activities and the expression of TNF-α and P-selectin, reduced myocardial edema in the left ventricle and the reflow and no-reflow areas and the expression of aquaporin-4, -8, and -9, and decreased myocytes apoptosis by regulation of apoptotic protein expression in the reflow and no-reflow myocardium. However, addition of the PKA inhibitor H-89 counteracted these beneficial effects of TXL. CONCLUSION: PKA-mediated cardioprotection of TXL against no-reflow and reperfusion injury relates to the inhibition of myocardial inflammation, edema, and apoptosis in the reflow and no-reflow myocardium.

CREB regulates the expression of neuronal glucose transporter 3: a possible mechanism related to impaired brain glucose uptake in Alzheimer's disease.

Impaired brain glucose uptake and metabolism precede the appearance of clinical symptoms in Alzheimer disease (AD). Neuronal glucose transporter 3 (GLUT3) is decreased in AD brain and correlates with tau pathology. However, what leads to the decreased GLUT3 is yet unknown. In this study, we found that the promoter of human GLUT3 contains three potential cAMP response element (CRE)-like elements, CRE1, CRE2 and CRE3. Overexpression of CRE-binding protein (CREB) or activation of cAMP-dependent protein kinase significantly increased GLUT3 expression. CREB bound to the CREs and promoted luciferase expression driven by human GLUT3-promoter. Among the CREs, CRE2 and CRE3 were required for the promotion of GLUT3 expression. Full-length CREB was decreased and truncation of CREB was increased in AD brain. This truncation was correlated with calpain I activation in human brain. Further study demonstrated that calpain I proteolysed CREB at Gln28-Ala29 and generated a 41-kDa truncated CREB, which had less activity to promote GLUT3 expression. Importantly, human brain GLUT3 was correlated with full-length CREB positively and with activation of calpain I negatively. These findings suggest that overactivation of calpain I caused by calcium overload proteolyses CREB, resulting in a reduction of GLUT3 expression and consequently impairing glucose uptake and metabolism in AD brain.

Antidepressant-like effect of Fuzi total alkaloid on ovariectomized mice.

Recent studies in vivo and vitro have shown that Fuzi polysaccharide has an antidepressant-like effect. Polysaccharide and total alkaloid are the two most important components of Fuzi. However, little is known about the antidepressant-like effect of Fuzi total alkaloid. To investigate the antidepressant-like effect of Fuzi total alkaloid, behavioral studies were performed in the open field test and forced swimming test. Repeated intragastric administration of Fuzi total alkaloid for 7 days (10 mg/kg) to normal mice decreased immobility time compared to the vehicle group. Furthermore, repeated administration of Fuzi total alkaloid (10 or 30 mg/kg) to ovariectomized mice also decreased immobility time in a dose-dependent manner. However, these antidepressant-like behavioral effects were not simply due to locomotor hyperactivity. Further experiments showed that Fuzi total alkaloid enhanced the ratio of phospho-CREB/CREB (cAMP response element-binding) and BDNF (brain-derived neurotrophic factor) protein level in the frontal cortex and hippocampus in ovariectomized mice but not in normal mice. These results indicate that the CREB-BDNF pathway may be involved in the antidepressant-like effect of Fuzi total alkaloid in ovariectomized mice.

Insulin/IGF-I regulation of necdin and brown adipocyte differentiation via CREB- and FoxO1-associated pathways.

Brown adipose tissue plays an important role in obesity, insulin resistance, and diabetes. We have previously shown that the transition from brown preadipocytes to mature adipocytes is mediated in part by insulin receptor substrate (IRS)-1 and the cell cycle regulator protein necdin. In this study, we used pharmacological inhibitors and adenoviral dominant negative constructs to demonstrate that this transition involves IRS-1 activation of Ras and ERK1/2, resulting in phosphorylation of cAMP response element-binding protein (CREB) and suppression of necdin expression. This signaling did not include an elevation of intracellular calcium. A constitutively active form of CREB expressed in IRS-1 knockout cells decreased necdin promoter activity, necdin mRNA, and necdin protein levels, leading to a partial restoration of differentiation. By contrast, forkhead box protein (Fox)O1, which is regulated by the phosphoinositide 3 kinase-Akt pathway, increased necdin promoter activity. Based on reporter gene assays using truncations of the necdin promoter and chromatin immunoprecipitation studies, we demonstrated that CREB and FoxO1 are recruited to the necdin promoter, likely interacting with specific consensus sequences in the proximal region. Based on these results, we propose that insulin/IGF-I act through IRS-1 phosphorylation to stimulate differentiation of brown preadipocytes via two complementary pathways: 1) the Ras-ERK1/2 pathway to activate CREB and 2) the phosphoinositide 3 kinase-Akt pathway to deactivate FoxO1. These two pathways combine to decrease necdin levels and permit the clonal expansion and coordinated gene expression necessary to complete brown adipocyte differentiation.

p38-targeted inhibition of interleukin-12 expression by ethanol extract from Cordyceps bassiana in lipopolysaccharide-activated macrophages.

Cordyceps species have been known as ethnopharmacologically valuable mushroom in Korea, China, and Japan. This plant has been reported to exhibit a variety of pharmacological activities such as antioxidative, anticancer, anti-inflammatory, antidiabetic, and antiobesity effects. Although numerous pharmacological potentials of Cordyceps spp. have been demonstrated, immunomodulatory effect of Cordyceps bassiana has not been published yet. To evaluate its immunomodulatory activity, macrophages activated by lipopolysaccharide (LPS) were employed and the production of interleukin-12 (IL-12) was explored in terms of understanding its molecular inhibitory mechanism. Seventy percent of ethanol extract from Cordyceps bassiana (Cb-EE) was able to suppress the expression of IL-12, a cytokine regulating interferon-γ (IFN-γ)-producing T helper type 1 (Th1) polarization response, at the transcriptional levels. The inhibitory effect of Cb-EE seemed to be due to activator protein-1 (AP-1) translocation inhibition, according to immunoblotting analysis with nuclear fraction and luciferase assay. In agreement with this, Cb-EE strongly suppressed the phosphorylation of p38, a prime signal to stimulate AP-1 translocation and IL-12 production, strongly suppressed by SB203580, a p38 inhibitor. Furthermore, this extract also suppressed IFN-γ production in both phytohemaglutinin A and LPS-activated splenocytes. Our results suggest that Cb-EE can be applied as a Th1 response regulatory herbal medicine.

A genome-wide RNA interference screen reveals an essential CREB3L2-ATF5-MCL1 survival pathway in malignant glioma with therapeutic implications.

Activating transcription factor-5 (ATF5) is highly expressed in malignant glioma and has a key role in promoting cell survival. Here we perform a genome-wide RNAi screen to identify transcriptional regulators of ATF5. Our results reveal an essential survival pathway in malignant glioma, whereby activation of a RAS-mitogen-activated protein kinase or phosphoinositide-3-kinase signaling cascade leads to induction of the transcription factor cAMP response element-binding protein-3-like-2 (CREB3L2), which directly activates ATF5 expression. ATF5, in turn, promotes survival by stimulating transcription of myeloid cell leukemia sequence-1 (MCL1), an antiapoptotic B cell leukemia-2 family member. Analysis of human malignant glioma samples indicates that ATF5 expression inversely correlates with disease prognosis. The RAF kinase inhibitor sorafenib suppresses ATF5 expression in glioma stem cells and inhibits malignant glioma growth in cell culture and mouse models. Our results demonstrate that ATF5 is essential in malignant glioma genesis and reveal that the ATF5-mediated survival pathway described here provides potential therapeutic targets for treatment of malignant glioma.

Reduced blockade by extracellular Mg(2+) is permissive to NMDA receptor activation in cerebellar granule neurons that model a migratory phenotype.

NMDA receptors (NMDAR) contribute to neuronal development throughout the CNS. However, their mode(s) of activation preceding synaptic maturation is unclear, as they are not co-localized with alpha-amino-3-hydroxy-5-methylisoxazole-4-propionate receptors (AMPARs) which normally provide sufficient depolarization to relieve voltage-dependent blockade by Mg(2+). We used cerebellar granule neurons (CGNs) cultured at a near-physiological KCl concentration to examine maturation-dependent changes in NMDAR responses. In contrast, most studies use KCl-supplemented medium to promote survival. At 2-4 days in vitro CGNs: (i) express developmental markers resembling the in vivo migratory phenotype; (ii) maintain a basal amount of calcium responsive element-binding protein phosphorylation that requires NMDARs and calcium/calmodulin-dependent kinases, but not AMPARs; (iii) exhibit NMDA-mediated Ca(2+) influx not effectively blocked by ambient Mg(2+) (0.75 mM) or AMPARs; (iv) maintain a more depolarized resting membrane potential and increased resistance compared to synaptically-connected CGNs. Moreover, migrating CGNs in explant cultures demonstrate NMDA-mediated Ca(2+) influx not effectively blocked by 0.75 mM Mg(2+), and NMDAR but not AMPAR antagonists slow migration. These data suggest the biophysical properties of immature CGNs render NMDARs less sensitive to Mg(2+) blockade, enhancing the likelihood of activation in the absence of AMPAR depolarization.

Scopolamine induced amnesia is reversed by Bacopa monniera through participation of kinase-CREB pathway.

Scopolamine, an anticholinergic drug, is reported to produce amnesia by interference of long term potentiation and has been used for discerning the efficacy of various antiamnesic drugs. The intoxication with anticholinergics and benzodiazepines tend to produce neurodegeneration which cause memory deficits. Our earlier reports have shown the antiamnesic drug, B. monniera to be capable of alleviating diazepam induced memory deficits. We have now tested how scopolamine affects downstream signaling molecules of long term potentiation and if B. monniera can also modulate the scopolamine induced amnesia. We used Morris water maze scale to test the amnesic effect of scopolamine and its reversal by B. monniera. Rota-rod test was used to screen muscle coordination activity of mice before water maze investigations were carried out. The results showed that scopolamine downregulated protein kinase C and iNOS without affecting cAMP, protein kinase A, calmodulin, MAP kinase, nitrite, CREB and pCREB. B. monniera reversed the scopolamine induced amnesia by significantly improving calmodulin and by partially attenuating protein kinase C and pCREB. These observations suggest involvement of calmodulin in evoking antiamnesic effects of B. monniera.

Hop bitter acids efficiently block inflammation independent of GRalpha, PPARalpha, or PPARgamma.

Hop (Humulus lupulus L.) is an essential ingredient of beer, where it provides the typical bitter taste, but is also applied in traditional folk medicine for sedative and antibacterial purposes. In this study, we demonstrate and compare the anti-inflammatory effect of various classes of hop bitter acids (HBA), including alpha-acids (AA), beta-acids (BA), and iso-alpha-acids (IAA), in fibroblasts, which are important players in the inflammatory response. All three studied classes of HBA blocked the tumor necrosis factor alpha (TNF)-induced production of the cytokine IL6, and inhibited the transactivation of the pro-inflammatory transcription factors nuclear factor kappa B (NF-kappaB), activator protein-1 (AP-1), and cAMP-response element-binding protein (CREB). In this respect, the six-membered ring compounds AA and BA showed equal potency, whereas the five-membered ring compounds, IAA, were effective only when used at higher concentrations. Furthermore, with regard to the mechanism of NF-kappaB suppression, we excluded a possible role for glucocorticoid receptor alpha (GRalpha), peroxisome proliferators-activated receptor alpha/gamma (PPARalpha or PPARgamma), nuclear receptors (NRs) that are also known to inhibit inflammation by directly interfering with the activity of pro-inflammatory transcription factors. Interestingly, combining hop acids and selective agonists for GRalpha, PPARalpha, or PPARgamma resulted in additive inhibition of NF-kappaB activity after TNF treatment, which may open up new avenues for combinatorial anti-inflammatory strategies with fewer side effects. Finally, systemic administration of HBA efficiently inhibited acute local inflammation in vivo.

[Effects of prenatal taurine on mRNA expression of PKA CREB signal pathway and glial cell line derived neurotrophic factor in fetal rat brains of intrauterine growth restriction].

OBJECTIVE: This study examined the effects of prenatal application of taurine on mRNA expression of protein kinase A cAMP response element binding protein (PKA-CREB) signal pathway and glial cell line derived neurotrophic factor (GDNF) in fetal rat brains of intrauterine growth restriction (IUGR). METHODS: Pregnant rats were randomly divided into 4 groups: normal control, IUGR model, low dose (100 mg/kg x d) and high dose (300 mg/kg x d) taurine treatment IUGR (n = 5 each). IUGR was induced by food restriction throughout pregnancy. PKA, CREB and GDNF mRNA expression in brains of newborn rats was detected by reverse transcription polymerase chain reaction (RT-PCR). RESULTS: PKA, CREB and GDNF mRNA expression in the IUGR model group was significantly higher than that in the normal control group (p<0.05). Compared with the IUGR model group, mRNA expression of PKA and CREB in both the low dose and high dose taurine treatment groups increased significantly (p<0.05); GDNF mRNA expression in the high dose taurine treatment group also increased significantly (p<0.01). CONCLUSIONS: Taurine can increase mRNA expression of PKA, CREB and GDNF in fetal rat brains of IUGR. This suggests that prenatal application of taurine may increase neurogenesis of the central nervous system and endogenous secretion of neurotrophic factors, thus providing neuroprotective effects.

Bidirectional regulation of the cAMP response element binding protein encodes spatial map alignment in prism-adapting barn owls.

The barn owl midbrain contains mutually aligned maps of auditory and visual space. Throughout life, map alignment is maintained through the actions of an instructive signal that encodes the magnitude of auditory-visual mismatch. The intracellular signaling pathways activated by this signal are unknown. Here we tested the hypothesis that CREB (cAMP response element-binding protein) provides a cell-specific readout of instructive information. Owls were fitted with prismatic or control spectacles and provided rich auditory-visual experience: hunting live mice. CREB activation was analyzed within 30 min of hunting using phosphorylation state-specific CREB (pCREB) and CREB antibodies, confocal imaging, and immunofluorescence measurements at individual cell nuclei. In control owls or prism-adapted owls, which experience small instructive signals, the frequency distributions of pCREB/CREB values obtained for cell nuclei within the external nucleus of the inferior colliculus (ICX) were unimodal. In contrast, in owls adapting to prisms or readapting to normal conditions, the distributions were bimodal: certain cells had received a signal that positively regulated CREB and, by extension, transcription of CREB-dependent genes, whereas others received a signal that negatively regulated it. These changes were restricted to the subregion of the inferior colliculus that received optically displaced input, the rostral ICX, and were not evident in the caudal ICX or central nucleus. Finally, the topographic pattern of CREB regulation was patchy, not continuous, as expected from the actions of a topographically precise signal encoding discrete events. These results support a model in which the magnitude of CREB activation within individual cells provides a readout of the instructive signal that guides plasticity and learning.

Inhibition of MITF and tyrosinase by paeonol-stimulated JNK/SAPK to reduction of phosphorylated CREB.

Tyrosinase and its transcriptional regulator microphthalmia-associated transcription factor (MITF) play critical roles in regulation of melanogenesis, and are required for environmental cues or agents in modulation of melanin synthesis. Identifying the signals regulating tyrosinase and MITF is crucial to understanding how pigmentation responds to extracellular stimuli. In this report, we discovered that paeonol down-regulated melanin production via decreasing MITF expression and consequent mRNA and protein levels of tyrosinase. We also found that paeonol reduced phosphorylation of a cAMP responsive element binding protein (phospho-CREB), which binds and activates MITF. A selective inhibitor of c-jun N-terminal or stress-activated protein kinases (JNK/SAPK)-SP600125 significantly reversed paeonol-induced down-regulation of melanogenesis. Inhibition of cAMP/PKA pathway intensified the hypopigmentation response to paeonol. These results identify a mechanism in which paeonol induces the down-regulation of melanogenesis through inhibition of CREB phosphorylation, leading to the expression reduction of MITF and subsequently tyrosinase. The key kinase mediating the effects of paeonol on melanogenesis in B16F10 cells is JNK/SAPK. Additionally, the cAMP/PKA pathway may take part in this process.

Interference of endocrine disrupting chemicals with aromatase CYP19 expression or activity, and consequences for reproduction of teleost fish.

Many natural and synthetic compounds present in the environment exert a number of adverse effects on the exposed organisms, leading to endocrine disruption, for which they were termed endocrine disrupting chemicals (EDCs). A decrease in reproduction success is one of the most well-documented signs of endocrine disruption in fish. Estrogens are steroid hormones involved in the control of important reproduction-related processes, including sexual differentiation, maturation and a variety of others. Careful spatial and temporal balance of estrogens in the body is crucial for proper functioning. At the final step of estrogen biosynthesis, cytochrome P450 aromatase, encoded by the cyp19 gene, converts androgens into estrogens. Modulation of aromatase CYP19 expression and function can dramatically alter the rate of estrogen production, disturbing the local and systemic levels of estrogens. In the present review, the current progress in CYP19 characterization in teleost fish is summarized and the potential of several classes of EDCs to interfere with CYP19 expression and activity is discussed. Two cyp19 genes are present in most teleosts, cyp19a and cyp19b, primarily expressed in the ovary and brain, respectively. Both aromatase CYP19 isoforms are involved in the sexual differentiation and regulation of the reproductive cycle and male reproductive behavior in diverse teleost species. Alteration of aromatase CYP19 expression and/or activity, be it upregulation or downregulation, may lead to diverse disturbances of the above mentioned processes. Prediction of multiple transcriptional regulatory elements in the promoters of teleost cyp19 genes suggests the possibility for several EDC classes to affect cyp19 expression on the transcriptional level. These sites include cAMP responsive elements, a steroidogenic factor 1/adrenal 4 binding protein site, an estrogen-responsive element (ERE), half-EREs, dioxin-responsive elements, and elements related to diverse other nuclear receptors (peroxisome proliferator activated receptor, retinoid X receptor, retinoic acid receptor). Certain compounds including phytoestrogens, xenoestrogens, fungicides and organotins may modulate aromatase CYP19 activity on the post-transcriptional level. As is shown in this review, diverse EDCs may affect the expression and/or activity of aromatase cyp19 genes through a variety of mechanisms, many of which need further characterization in order to improve the prediction of risks posed by a contaminated environment to teleost fish population.

Regulation of Cox-2 by cyclic AMP response element binding protein in prostate cancer: potential role for nexrutine.

We recently showed that Nexrutine, a Phellodendron amurense bark extract, suppresses proliferation of prostate cancer cell lines and tumor development in the transgenic adenocarcinoma of mouse prostate (TRAMP) model. Our data also indicate that the anti-proliferative effects of Nexrutine are emediated in part by Akt and Cyclic AMP response element binding protein (CREB). Cyclooxygenase (Cox-2), a pro-inflammatory mediator, is a CREB target that induces prostaglandin E(2) (PGE(2)) and suppresses apoptosis. Treatment of LNCaP cells with Nexrutine reduced tumor necrosis factor alpha-induced enzymatic as well as promoter activities of Cox-2. Nexrutine also reduced the expression and promoter activity of Cox-2 in PC-3 cells that express high constitutive levels of Cox-2. Deletion analysis coupled with mutational analysis of the Cox-2 promoter identified CRE as being sufficient for mediating Nexrutine response. Immunohistochemical analysis of human prostate tumors show increased expression of CREB and DNA binding activity in high-grade tumors (three-fold higher in human prostate tumors compared to normal prostate; P = .01). We have identified CREB-mediated activation of Cox-2 as a potential signaling pathway in prostate cancer which can be blocked with a nontoxic, cost-effective dietary supplement like Nexrutine, demonstrating a prospective for development of Nexrutine for prostate cancer management.

CREB and the discovery of cognitive enhancers.

In the past few years, a series of molecular-genetic, biochemical, cellular and behavioral studies in fruit flies, sea slugs and mice have confirmed a long-standing notion that long-term memory formation depends on the synthesis of new proteins. Experiments focused on the cAMP-responsive transcription factor, CREB, have established that neural activity-induced regulation of gene transcription promotes a synaptic growth process that strengthens the connections among active neurons. This process constitutes a physical basis for the engram--and CREB is a "molecular switch" to produce the engram. Helicon Therapeutics has been formed to identify drug compounds that enhance memory formation via augmentation of CREB biochemistry. Candidate compounds have been identified from a high throughput cell-based screen and are being evaluated in animal models of memory formation. A gene discovery program also seeks to identify new genes, which function downstream of CREB during memory formation, as a source for new drug discoveries in the future. Together, these drug and gene discovery efforts promise new class of pharmaceutical therapies for the treatment of various forms of cognitive dysfunction.