Cyclic Adenosine Monophosphate Response Element Research Articles

Hippocampal Salt-Inducible Kinase 2 Plays a Role in Depression via the CREB-Regulated Transcription Coactivator 1–cAMP Response Element Binding–Brain-Derived Neurotrophic Factor Pathway

BackgroundDeveloping novel pharmacological targets beyond monoaminergic systems is now a popular strategy for finding new ways to treat depression. Salt-inducible kinase (SIK) is a kinase that regulates the nuclear translocation of cyclic adenosine monophosphate response element binding protein (CREB)-regulated transcription coactivator (CRTC) by phosphorylation. Here, we hypothesize that dysfunction of the central SIK-CRTC system may contribute to the pathogenesis of depression. MethodsChronic social defeat stress (CSDS) and chronic unpredictable mild stress (CUMS) models of depression, various behavioral tests, viral-mediated gene transfer, Western blotting, coimmunoprecipitation, quantitative real-time reverse transcription polymerase chain reaction, and immunohistochemistry were used in this study (for in vivo studies, n = 10; for in vitro studies, n = 5). ResultsBoth CSDS and CUMS markedly increased the expression of hippocampal SIK2, which reduced CRTC1 nuclear translocation and binding of CRTC1 and CREB in the hippocampus. Genetic overexpression of hippocampal SIK2 in naïve mice simulated chronic stress, inducing depressive-like behaviors in the forced swim test, tail suspension test, sucrose preference test, and social interaction test, as well as decreasing the brain-derived neurotrophic factor signaling cascade and neurogenesis in the hippocampus. In contrast, genetic knockdown and knockout of hippocampal SIK2 protected against CSDS and CUMS, exerting significant antidepressant-like effects that were mediated via the downstream CRTC1-CREB–brain-derived neurotrophic factor pathway. Moreover, fluoxetine, venlafaxine, and mirtazapine all significantly restored the effects of CSDS and CUMS on the hippocampal SIK2-CRTC1 pathway, which was necessary for their antidepressant actions. ConclusionsThe hippocampal SIK2-CRTC1 pathway is involved in the pathogenesis of depression, and hippocampal SIK2 could be a novel target for the development of antidepressants.

Social defeat stress before pregnancy induces depressive-like behaviours and cognitive deficits in adult male offspring: correlation with neurobiological changes

BackgroundEpidemiological surveys and studies with animal models have established a relationship between maternal stress and affective disorders in their offspring. However, whether maternal depression before pregnancy influences behaviour and related neurobiological mechanisms in the offspring has not been studied.ResultsA social defeat stress (SDS) maternal rat model was established using the resident-intruder paradigm with female specific pathogen-free Wistar rats and evaluated with behavioural tests. SDS maternal rats showed a significant reduction in sucrose preference and locomotor and exploratory activities after 4 weeks of stress. In the third week of the experiment, a reduction in body weight gain was observed in SDS animals. Sucrose preference, open field, the elevated-plus maze, light–dark box, object recognition, the Morris water maze, and forced swimming tests were performed using the 2-month-old male offspring of the female SDS rats. Offspring subjected to pre-gestational SDS displayed enhanced anxiety-like behaviours, reduced exploratory behaviours, reduced sucrose preference, and atypical despair behaviours. With regard to cognition, the offspring showed significant impairments in the retention phase of the object recognition test, but no effect was observed in the acquisition phase. These animals also showed impairments in recognition memory, as the discrimination index in the Morris water maze test in this group was significantly lower for both 1 h and 24 h memory retention compared to controls. Corticosterone, adrenocorticotropic hormone, and monoamine neurotransmitters levels were determined using enzyme immunoassays or radioimmunoassays in plasma, hypothalamus, left hippocampus, and left prefrontal cortex samples from the offspring of the SDS rats. These markers of hypothalamic–pituitary–adrenal axis responsiveness and the monoaminergic system were significantly altered in pre-gestationally stressed offspring. Brain-derived neurotrophic factor (BDNF), cyclic adenosine monophosphate response element binding protein (CREB), phosphorylated CREB (pCREB), and serotonin transporter (SERT) protein levels were evaluated using western blotting with right hippocampus and right prefrontal cortex samples. Expression levels of BDNF, pCREB, and SERT in the offspring were also altered in the hippocampus and in the prefrontal cortex; however, there was no effect on CREB.ConclusionWe conclude that SDS before pregnancy might induce depressive-like behaviours, cognitive deficits, and neurobiological alterations in the offspring.

Downregulation of thioredoxin-1 in the ventral tegmental area delays extinction of methamphetamine-induced conditioned place preference.

Drug addiction is characterized by compulsive drug use and relapse. Thioredoxin-1 is emerging as an important modulator involved in the cellular protective response against a variety of toxic stressors. Previous study has reported that thioredoxin-1 overexpression prevents the acquisition of methamphetamine-conditioned place preference. Here, we aimed to investigate the effect of thioredoxin-1 on methamphetamine-conditioned place preference extinction and the possible mechanism. (a) An extinction procedure in mice was employed to investigate the effect of thioredoxin-1 on the extinction of methamphetamine-conditioned place preference. After the acquisition of methamphetamine-conditioned place preference, mice underwent the following procedures: the injection of thioredoxin-1 small interfering RNA in the ventral tegmental area followed by the post-conditioned place preference test, four days of extinction training followed by four days of recovery after surgery. (b) The levels of thioredoxin-1, dopamine D1 receptor, tyrosine hydroxylase, phosphorylated extracellular regulated kinase, and phosphorylated cyclic adenosine monophosphate response element binding protein were examined by using Western blot analysis. Thioredoxin-1 downregulation in the ventral tegmental area delayed methamphetamine-conditioned place preference extinction. The expression of thioredoxin-1 was decreased in the ventral tegmental area of mice in control and negative groups after methamphetamine-conditioned place preference extinction, but not in the thioredoxin-1 siRNA group. The levels of dopamine D1 receptor, tyrosine hydroxylase, phosphorylated extracellular regulated kinase, and phosphorylated cyclic adenosine monophosphate response element binding protein were decreased in the ventral tegmental area, nucleus accumbens, and prefrontal cortex of mice in the control and negative groups after methamphetamine-conditioned place preference extinction, but were inversely increased in thioredoxin-1 siRNA group. The results suggest that downregulation of thioredoxin-1 in the ventral tegmental area may delay methamphetamine-conditioned place preference extinction by regulating the mesocorticolimbic dopaminergic signaling pathway.

Gintonin Attenuates D-Galactose-Induced Hippocampal Senescence by Improving Long-Term Hippocampal Potentiation, Neurogenesis, and Cognitive Functions

Background: Ginseng has been used to improve brain function and increase longevity. However, little is known about the ingredients of ginseng and molecular mechanisms of its anti-brain aging effects. Gintonin is a novel exogenous ginseng-derived lysophosphatidic acid (LPA) receptor ligand; LPA and LPA1 receptors are involved in adult hippocampal neurogenesis. D-galactose (D-gal) is used to induce brain ­aging in animal models because long-term treatment with D-gal facilitates hippocampal aging in experimental adult animals by decreasing hippocampal neurogenesis and inducing learning and memory dysfunction. Objective: To investigate the protective effects of gintonin on D-gal-induced hippocampal senescence, impairment of long-term potentiation (LTP), and memory dysfunction. Methods: Brain hippocampal aging was induced by D-gal administration (150 mg/kg/day, s.c.; 10 weeks). From the 7th week, gintonin (50 or 100 mg/kg/day, per os) was co-administered with D-gal for 4 weeks. We performed histological analyses, LTP measurements, and object location test. Results: Co-administration of gintonin ameliorated D-gal-induced reductions in hippocampal Ki67-immunoreactive proliferating cells, doublecortin-immunoreactive neuroblasts, 5-bromo-2’-deoxyuridine-incorporating NeuN-immunoreactive mature neurons, and LPA1 receptor expression. Co-administration of gintonin in D-gal-treated mice increased the expression of phosphorylated cyclic adenosine monophosphate response element binding protein in the hippocampal dentate gyrus. In addition, co-administration of gintonin in D-gal-treated mice enhanced LTP and restored the cognitive functions compared with those in mice treated with D-gal only. Conclusion: These results show that gintonin administration restores D-gal-induced memory deficits by enhancing hippocampal LPA1 receptor expression, LTP, and neurogenesis. Finally, the present study shows that gintonin exerts anti-brain aging effects that are responsible for alleviating brain aging-related dysfunction.

Analysis of gene expression and functional changes of adrenal gland in a rat model of kidney yang deficiency syndrome treated with Sini decoction.

Sini decoction (SND), a well-known traditional Chinese medicine, has been used to treat kidney Yang deficiency for ~1,800 years. The present study aimed to evaluate the effects of SND treatment on hypothalamic-pituitary-adrenal axis hormones in a rat model of Yang deficiency and to explore the molecular mechanisms using microarray analysis of adrenal glands and in vitro adrenocortical cell culture systems. The results indicated that SND treatment recovered circulating serum cortisol, adrenocortical hormone (ACTH) and testosterone levels in a yang deficiency model. Immunohistochemical analysis of pituitary and hypothalamic tissues confirmed increased expression of ACTH and corticotropin-releasing factor, respectively, in response to SND treatment. Microarray analysis identified a marked upregulation of genes involved in ≤metabolic and stress response pathways in rat adrenal tissues in response to SND treatment, exemplified by cyclooxygenase-2 and nuclear factor (NF)-κB. In vitro, SND exerted a protective effect on mitochondria in response to H2O2 exposure also activated NF-κB and cyclic adenosine monophosphate response element binding protein reporter gene activity. These results contributed towards an improved understanding of how SND effectively alleviates the symptoms of kidney Yang deficiency syndrome at the molecular level.

Possible mechanism of Vitis vinifera L. flavones on neurotransmitters, synaptic transmission and related learning and memory in Alzheimer model rats

BackgroundThis study explored the possible mechanism of flavones from Vitis vinifera L. (VTF) on neurotransmitters, synaptic transmission and related learning and memory in rats with Alzheimer disease (AD).MethodsThe researchers injected amyloid-β(25–35) into the hippocampus to establish AD model rats. The Sprague-Dawley (SD) rats were divided into a control group, a donepezil group, an AD model group, a VTF low-dose group, a VTF medium-dose group and a VTF high-dose group. The researchers detected the activity of choline acetyltransferase (ChAT) and acetylcholinesterase (AChE) according to kit instructions. The protein expression of brain-derived neurotrophic factor (BDNF), synaptotagmin-1 (SYT1) and cyclic adenosine monophosphate response element binding protein (CREB) in the rats’ hippocampi was detected by immunohistochemistry and Western blot, and the gene expression of cAMP-regulated enhancer (CRE) was detected by real-time quantitative polymerase chain reaction (PCR).ResultsVTF may enhance the protein expression of p-CREB, BDNF and SYT1 in rat hippocampi, depending on dose. The messenger RNA (mRNA) level of CREB was significantly higher in the VTF high-dose group than in the model group, which was consistent with the results of Western blotting. VTF may reduce the activity of AChE and increase that of ChAT in rat hippocampi. Finally, VTF effectively improved the learning and memory abilities of AD rats.ConclusionsVTF can promote synaptic plasticity and indirectly affect the expression of cholinergic neurotransmitters, which may be one mechanism of VTF protection in AD rats.

Misaligned Feeding May Aggravate Pain by Disruption of Sleep-Awake Rhythm.

Increasing evidence suggests that patients with eating disorders are more likely to develop chronic pain. A misaligned diet has been reported to disrupt the sleep-awake rhythms. Combined with our previous investigation on circadian pain, we aimed to investigate the role of misaligned diet in the pain sensitivity and the underlying mechanisms. Two-month-old C57BL/6J male mice were administered chronic constriction injury (CCI) surgery to establish neuropathic pain models. CCI mice were randomized to scheduled food access throughout the whole day (CCI-free), during the daytime (CCI-misaligned), and at night (CCI-aligned), respectively. The paw withdrawal mechanical threshold, indicating pain behavior, was measured by Von Frey. The gross motor activity pattern indicating the sleep-awake rhythm was monitored by Mini-Mitter. Melatonin (Mel) was administered to ameliorate the sleep-awake rhythm (CCI-free + Mel and CCI-misaligned + Mel). The expressions of circadian pain-related proteins were detected by quantitative polymerase chain reaction and western blot. The primary outcome is the pain threshold and the secondary outcome is the sleep-awake rhythm. Misaligned diet during the peri-CCI surgery period significantly decreased the paw withdrawal mechanical threshold compared with the CCI-free mice (day 14: 0.40 ± 0.09 vs 0.64 ± 0.15; P = .03;) and altered the sleep-awake rhythm. Mel pretreatment alleviated the increased pain (day 14, CCI-misaligned + Mel versus CCI-misaligned: day 14: 0.60 ± 0.13 vs 0.35 ± 0.12; P = .022) and the disrupted sleep-awake rhythm caused by misaligned feeding. The mRNA levels of N-methyl-D-aspartate receptor subtype 2B (NR2B), Ca/calmodulin-dependent protein kinase II (CaMKII), and cyclic adenosine monophosphate-response element binding protein (CREB) in the spinal dorsal horn increased in CCI-misaligned mice compared with the CCI-free mice. The phosphor-NR2B, phosphor-CaMKII, and phosphor-CREB also increased in CCI-misaligned mice compared with the CCI-free mice. However, the expressions of NR2B, CaMKII, and CREB were decreased in CCI-misaligned + Mel mice compared to CCI-misaligned mice at both transcriptional and translational levels. Misaligned diet might aggravate pain sensitivity through the disruption of the sleep-awake cycle, which could be recovered by Mel. NR2B-CaMKII-CREB may participate in the disruption of sleep-awake rhythm-mediated pain aggravation.

MK-0677, a Ghrelin Agonist, Alleviates Amyloid Beta-Related Pathology in 5XFAD Mice, an Animal Model of Alzheimer's Disease.

Alzheimer’s disease (AD) is a progressive neurodegenerative disorder characterized by cognitive deficits, neuroinflammation, and neuronal death. The primary pathogenic cause is believed to be the accumulation of pathogenic amyloid beta (Aβ) assemblies in the brain. Ghrelin, which is a peptide hormone predominantly secreted from the stomach, is an endogenous ligand for the growth hormone secretagogue-receptor type 1a (GHS-R1a). MK-0677 is a ghrelin agonist that potently stimulates the GHS-R1a ghrelin receptor. Interestingly, previous studies have shown that ghrelin improves cognitive impairments and attenuates neuronal death and neuroinflammation in several neurological disorders. However, it is unknown whether MK-0677 can affect Aβ accumulation or Aβ-mediated pathology in the brains of patients with AD. Therefore, we examined the effects of MK-0677 administration on AD-related pathology in 5XFAD mice, an Aβ-overexpressing transgenic mouse model of AD. MK-0677 was intraperitoneally administered to three-month-old 5XFAD mice. To visualize Aβ accumulation, neuroinflammation, and neurodegeneration, thioflavin-S staining and immunostaining with antibodies against Aβ (4G8), ionized calcium-binding adaptor molecule 1 (Iba-1), glial fibrillary acidic protein (GFAP), neuronal nuclear antigen (NeuN), and synaptophysin were conducted in the neocortex of 5XFAD and wild-type mice, and to evaluate changes of phosphorylated cyclic adenosine monophosphate (cAMP) response element binding protein (pCREB) levels, immunostaining with antibody against pCREB was performed in dentate gyrus of the hippocampus of 5XFAD and wild-type mice. The histological analyses indicated that MK-0677-treated 5XFAD mice showed reduced Aβ deposition, gliosis, and neuronal and synaptic loss in the deep cortical layers, and inhibited the decrement of pCREB levels in dentate gyrus of the hippocampus compared to vehicle-treated 5XFAD mice. Our results showed that activation of the ghrelin receptor with MK-0677 inhibited the Aβ burden, neuroinflammation, and neurodegeneration, which suggested that MK-0677 might have potential as a treatment of the early phase of AD.

Hepatocellular carcinoma cell-derived exosomes regulates Treg cells via cyclic adenosine monophosphate response element binding protein/forkhead/winged helix transcription factor P3 pathway

Objective To investigate whether hepatocellular carcinoma cell line HepG2 derived exosomes regulates Treg cells via cyclic adenosine monophosphate response element binding protein/forkhead/winged helix transcription factor P3 (CREB/Foxp3) pathway. Methods Ultracentrifugation was used to isolate exosomes of hepatocellular carcinoma cell line HepG2 and normal hepatocellular cell line L02. Transmission electron microscopy was used to determine the morphology of exosomes and Western blotting was used to detect the protein markers of exosomes and CREB/Foxp3 expression. HepG2-exo and L02-exo were co-cultured with peripheral blood mononuclear cells. The percent of Treg cells were determined by flow cytometry. Results Exosomes was about 30-100 nm with a circular or oval shape vesicular structure. CD81 and CD63 were highly expressed in exosomal proteins, while not expressed in cell proteins derived from HepG2 or L02 cells. Compared to L02-exo [(1.87±0.18)%] and blank control group [(1.43±0.12)%], HepG2-exo strongly increased the percent of Treg cells [(6.87±0.87)%], with P value of 0.005 and 0.004 respectively. Phosphorylation of CREB in HepG2-exo group was 1.74 and 1.63 fold higher than it in L02-exo and blank control group, and both of the P=0.001. Phosphorylation of Foxp3 in HepG2-exo group was 1.93 and 1.78 fold higher than it in L02-exo and blank control group, and both of the P=0.001. Conclusion These results provided evidence that hepatocellular carcinoma cell HepG2 derived exosomes could regulates Treg cells via CREB/Foxp3 pathway. Key words: Exsomes; Treg cell; Cyclic adenosine monophosphate response element binding protein; Forkhead/winged helix transcription factor P3; Hepatocellular carcinoma

Order-disorder transition of intrinsically disordered kinase inducible transactivation domain of CREB.

Transcription factor cyclic Adenosine monophosphate response-element binding protein plays a critical role in the cyclic AMP response pathway via its intrinsically disordered kinase inducible transactivation domain (KID). KID is one of the most studied intrinsically disordered proteins (IDPs), although most previous studies focus on characterizing its disordered state structures. An interesting question that remains to be answered is how the order-disorder transition occurs at experimental conditions. Thanks to the newly developed IDP-specific force field ff14IDPSFF, the quality of conformer sampling for IDPs has been dramatically improved. In this study, molecular dynamics (MD) simulations were used to study the order-to-disorder transition kinetics of KID based on the good agreement with the experiment on its disordered-state properties. Specifically, we tested four force fields, ff99SBildn, ff99IDPs, ff14IDPSFF, and ff14IDPs in the simulations of KID and found that ff14IDPSFF can generate more diversified disordered conformers and also reproduce more accurate experimental secondary chemical shifts. Kinetics analysis of MD simulations demonstrates that the order-disorder transition of KID obeys the first-order kinetics, and the transition nucleus is I127/L128/L141. The possible transition pathways from the nucleus to the last folded residues were identified as I127-R125-L138-L141-S143-A145 and L128-R125-L138-L141-S143-A145 based on a residue-level dynamical network analysis. These computational studies not only provide testable prediction/hypothesis on the order-disorder transition of KID but also confirm that the ff14IDPSFF force field can be used to explore the correlation between the structure and function of IDPs.

Abstract 692: Development of the Gene Therapy With CRE Decoy ODN to Prevent Vascular Intimal Hyperplasia

Background: Intimal hyperplasia (IH) is the main cause of vein graft stenosis or failure after bypass surgery. However, in the previous study, no therapeutic targets for the treatment of IH have been identified. Our recent research have been reported that the inhibition of Cyclic adenosine monophosphate response-element (CRE) binding protein (CREB) activation is a key role for vein graft IH. Objective: In consideration of future clinical application, we focused on decoy oligodeoxynucleotide (ODN) transfection as gene therapy strategy for suppressing IH. The goal of the present study is to identify whether the CRE decoy ODN had the therapeutic efficacy for suppressing IH. Methods: We developed phosphorothioate CRE decoy ODN and checked binding ability to a CRE sequence using CREB transcription assay . We chose a decoy ODN having high first-binding ability and transfected it to vascular smooth muscle cell(VSMC) in vitro. Proliferation was assessed using MTS assay and migration was assessed using a modified Boyden-chamber assay. We examined CRE activity using Luciferase reporter gene assay. We checked expression of mRNAs using qRT-PCR. In wire-injury mouse model(C57BL6,n=6), CRE decoy ODN was transfected to injured vessel wall using ultrasound-sonoporation method in vivo. Results: CREB transcription factor assay showed CRE decoy had about 80 folds binding ability of control decoy in IC50 value (vs.control,n=5). Transfer of CRE decoy ODN resulted in significantly downregulated CRE activity(vs.control,P<.01,n=12) and inhibited VSMC proliferation (vs.control,P<.01,n=12) and migration (vs.control,P<.01,n=5). In a wire-injury mouse model, histopathological analysis revealed that transfer of the CRE decoy ODN significantly repressed IH whereas intensive IH was observed in the control group. In this vessel tissue, Levels of mRNA CCNA2 and Bcl2 were significantly lower in CRE decoy group than in control group(n=6,P<.01,respectively). CRE-activated gene expression was strongly repressed. Conclusions: The present result suggested that CRE decoy ODN inhibiting CREB function provide an effective therapeutic approach to suppressing IH.

Cocaine Self-administration Alters Transcriptome-wide Responses in the Brain’s Reward Circuitry

BackgroundGlobal changes in gene expression underlying circuit and behavioral dysregulation associated with cocaine addiction remain incompletely understood. Here, we show how a history of cocaine self-administration (SA) reprograms transcriptome-wide responses throughout the brain’s reward circuitry at baseline and in response to context and/or cocaine re-exposure after prolonged withdrawal (WD). MethodsWe assigned male mice to one of six groups: saline/cocaine SA + 24-hour WD or saline/cocaine SA + 30-day WD + an acute saline/cocaine challenge within the previous drug-paired context. RNA sequencing was conducted on six interconnected brain reward regions. Using pattern analysis of gene expression and factor analysis of behavior, we identified genes that are strongly associated with addiction-related behaviors and uniquely altered by a history of cocaine SA. We then identified potential upstream regulators of these genes. ResultsWe focused on three patterns of gene expression that reflect responses to 1) acute cocaine, 2) context re-exposure, and 3) drug + context re-exposure. These patterns revealed region-specific regulation of gene expression. Further analysis revealed that each of these gene expression patterns correlated with an addiction index—a composite score of several addiction-like behaviors during cocaine SA—in a region-specific manner. Cyclic adenosine monophosphate response element binding protein and nuclear receptor families were identified as key upstream regulators of genes associated with such behaviors. ConclusionsThis comprehensive picture of transcriptome-wide regulation in the brain’s reward circuitry by cocaine SA and prolonged WD provides new insight into the molecular basis of cocaine addiction, which will guide future studies of the key molecular pathways involved.

Hepatic and cardiac beneficial effects of a long-acting Fc-apelin fusion protein in diet-induced obese mice.

Apelin is a peptide ligand of the G-protein-coupled receptor APJ and exhibits anti-diabetes and anti-heart failure activities. However, short serum half-life of the apelin peptide limits its potential clinical applications. This study aimed to develop a long-acting apelin analog. To extend apelin's in vivo half-life, we made a recombinant protein by fusing the IgG Fc fragment to apelin-13 (Fc-apelin-13), conducted pharmacokinetics studies in mice, and determined in vitro biological activities in suppressing cyclic adenosine monophosphate and activating extracellular signal-regulated kinase signalling by reporter assays. We investigated the effects of Fc-apelin-13 on food intake, body weight, fasting blood glucose and insulin levels, glucose tolerance test, hepatic steatosis, and cardiac function and fibrosis by subcutaneous administration of Fc-apelin-13 in diet-induced obese mice for 4weeks. The estimated half-life of Fc-apelin-13 in blood was approximately 33hours. Reporter assays showed that Fc-apelin-13 was active in suppressing cyclic adenosine monophosphate response element and activating serum response element activities. Four weeks of Fc-apelin-13 treatment in obese mice did not affect food intake and body weight, but resulted in a significant improvement of glucose tolerance, and a decrease in hepatic steatosis and fibrosis, as well as in serum alanine transaminase levels. Moreover, cardiac stroke volume and output were increased and cardiac fibrosis was decreased in the treated mice. Fc-apelin-13 fusion protein has an extended in vivo half-life and exerts multiple benefits on obese mice with respect to the improvement of glucose disposal, amelioration of liver steatosis and heart fibrosis, and increase of cardiac output. Hence, Fc-apelin-13 is potentially a therapeutic for obesity-associated disease conditions.

Protective effect of astaxanthin against cognitive impairment in offspring prenatally exposed to maternal epilepsy

Objective To investigate the protective effect of prenatal astaxanthin treatment against cognitive impairment in adult offspring induced by exposure to maternal seizures in utero. Methods Female adult Sprague-Dawley rats were randomly divided into four groups: control group, astaxanthin group, kindling group and kindling+astaxanthin group. Each rat was implanted with electrodes. Those in the kindling and kindling+astaxanthin groups were kindled once a day by electrical stimulation of the amygdala. All rats were allowed to mate after one week's amygdala kindling. Rats in the kindling and kindling+astaxanthin groups continued to be treated with electrical stimulation every 48 hours from gestational day 1 to 20, and those in the astaxanthin and kindling+astaxanthin groups were injected intraperitoneally with 30 mg/(kg·d) of astaxanthin simultaneously. Naturally delivered offspring were raised till 12 weeks of age. Morris water maze test was performed to assess the cognitive function of adult offspring. Changes in the morphology of hippocampus were observed with Nissal's staining and transmission electron microscope. Expression of cyclic adenosine monophosphate response element binding protein (CREB) and brain-derived neurotrophic factor (BDNF) in adult offsprings' hippocampus tissues at protein and mRNA levels were determined using Western-blotting and reverse transcription-polymerase chain reaction. Analysis of variance and LSD test were used as statistical methods. Results Morris water maze test showed that from the 3rd day to the 5th day, the kindling group had significantly longer escape latency [(36.33±7.85), (28.80±8.41), (29.50±11.72) s] than the control [(28.90±7.46), (17.59±9.12), (10.40±3.69) s] and kindling+astaxanthin groups [(28.30±5.75), (18.37±3.39), (15.23±6.63) s] (F=3.601, 9.811 and 14.226, all P<0.05). In probe trials, the kindling group had significantly fewer platform crossings as compared with the control and kindling+astaxanthin groups [(4.40±1.71) vs (7.20±1.62) and (6.50±1.84) times, F=6.586, P=0.001]. The kindling group spent dramatically less time in the target quadrant than the control and kindling+astaxanthin groups [(27.35±7.63) vs (58.29±10.48) and (40.41±7.06) s, F=25.825, P<0.001]. Nissl staining showed that hippocampal neurons of offspring in the control group were normal, but there was hippocampal damage in the kindling group and the damage was more severe than that in the kindling+astaxanthin group. Electron microscope observation showed that neurons and synapses in the hippocampal CA1 area of offspring in the control group were normal. However, obvious damage to neurons and synapses was induced in the kindling group and that was worse than the damage induced in the kindling+astaxanthin group. Expression of CREB and BDNF protein in the kindling group (0.19±0.06 and 0.32±0.04, respectively) were significantly lower than those in the control (0.81±0.11 and 0.93±0.04, respectively) and kindling+astaxanthin groups (0.60±0.07 and 0.80±0.06, respectively) (F were 34.015 and 71.074, both P<0.001). Moreover, the kindling group showed decreased expression of CREB and BDNF mRNA (0.48±0.11 and 0.43±0.08, respectively) as compared with the control (1.02±0.65 and 0.99±0.09, respectively) and kindling+astaxanthin groups (0.89±0.15 and 0.96±0.13, respectively) (F were 13.447 and 21.912, both P<0.01). Conclusion Treatment with astaxanthin could ameliorate the cognitive impairment and pathological damage in hippocampus of adult offspring induced by exposure to maternal seizures in utero through regulating the CREB-BDNF signal pathway. Key words: Pregnancy complications; Epilepsy; Xanthophylls; Oxidative stress; Rats

An adenosine�A1R-A2aR imbalance regulates low glucose/hypoxia-induced microglial activation, thereby contributing to oligodendrocyte damage through NF-κB and CREB phosphorylation

Microglial activation-mediated inflammatory damage to oligodendrocytes is a key step in the etiology of ischemic white matter lesions. The adenosineA1receptor (A1R) and adenosineA2areceptor (A2aR) have been reported to regulate the activation of microglia, however, the underlying mechanisms remain elusive. Thus, the present study used a microglia/oligodendrocyte co‑culture model exposed to low glucose/hypoxia, and treated with agonists/antagonists of A1R and A2aR to investigate the role of A1R and A2aR. Changes in A1R and A2aR expression and inflammatory cytokine secretion by the microglia, and oligodendrocyte damage, after exposure were examined. Low glucose/hypoxia induced a higher elevation of A1R than A2aR. In addition, activation of A1R inhibited A2aR protein expression and vice versa. The A1R antagonist DPCPX (100nM) and A2aR agonist CGS 21680 (100nM) inhibited microglial activation, reduced the production of inflammatory cytokines and attenuated oligodendrocyte damage, along with elevating the levels of phosphorylated nuclear factor (NF)‑κB and cyclic adenosine monophosphate response element binding protein (CREB). These data indicate that an A1R‑A2aR imbalance is able to modulate low glucose‑induced microglial activation and the cellular immune response through altering NF‑κB and CREB phosphorylation. This suggests that rebalancing A1R‑A2aR is a promising approach for treating white matter injury.

Antimelanogenesis and skin-protective activities of Panax ginseng calyx ethanol extract

BackgroundThe antioxidant effects of Panax ginseng have been reported in several articles; however, little is known about the antimelanogenesis effect, skin-protective effect, and cellular mechanism of Panax ginseng, especially of P. ginseng calyx. To understand how an ethanol extract of P. ginseng berry calyx (Pg-C-EE) exerts skin-protective effects, we studied its activities in activated melanocytes and reactive oxygen species (ROS)–induced keratinocytes. MethodsTo confirm the antimelanogenesis effect of Pg-C-EE, we analyzed melanin synthesis and secretion and messenger RNA and protein expression levels of related genes. Ultraviolet B (UVB) and hydrogen peroxide (H2O2) were used to induce cell damage by ROS generation. To examine whether this damage is inhibited by Pg-C-EE, we performed cell viability assays and gene expression and transcriptional activation analyses. ResultsPg-C-EE inhibited melanin synthesis and secretion by blocking activator protein 1 regulatory enzymes such as p38, extracellular signal-regulated kinases (ERKs), and cyclic adenosine monophosphate response element–binding protein. Pg-C-EE also suppressed ROS generation induced by H2O2 and UVB. Treatment with Pg-C-EE decreased the expression of matrix metalloproteinases, mitogen-activated protein kinases, and hyaluronidases and increased the cell survival rate. ConclusionThese results suggest that Pg-C-EE may have antimelanogenesis properties and skin-protective properties through regulation of activator protein 1 and cyclic adenosine monophosphate response element–binding protein signaling. Pg-C-EE may be used as a skin-improving agent, with moisture retention and whitening effects.

Glycyrrhizin attenuates histamine-mediated MUC5AC upregulation, inflammatory cytokine production, and aquaporin 5 downregulation through suppressing the NF-κB pathway in human nasal epithelial cells

Allergic rhinitis (AR) is a chronic respiratory inflammatory disease. Glycyrrhizin is a main bioactive component of the licorice root extract and exhibits anti-inflammatory activity. However, the role of glycyrrhizin in AR has not been studied. The aim of the present study was to investigate the effect of glycyrrhizin on histamine-induced human nasal epithelial cells (HNEpCs). Here, we found that glycyrrhizin (20 or 40 μM) inhibited histamine-induced the mRNA expression and secretion of mucin 5 subtype AC (MUC5AC), interleukin (IL)-6 and IL-8 in HNEpCs. The expression levels of aquaporin 5 (AQP5) and phosphorylated cyclic adenosine monophosphate-responsive element binding protein (p-CREB) were decreased by histamine in HNEpCs and increased in cells treated with glycyrrhizin. The glycyrrhizin treatment inhibited histamine-induced expressions of p-NF-κB p65 and p-IκBα in HNEpCs, indicating that glycyrrhizin inhibited the activation of NF-κB pathway in histamine-induced HNEpCs. In addition, inhibition of the NF-κB pathway exhibited the similar effect with glycyrrhizin on histamine-induced HNEpCs. In summary, the results showed that glycyrrhizin reversed the effect of histamine on MUC5AC expression, inflammatory cytokine production, and AQP5 expression in HNEpCs, and the NF-κB pathway was involved in the effect. Glycyrrhizin might be used for complementary and alternative therapeutics of AR.

Peripheral and Central Effects of Memantine in a Mixed Preclinical Mice Model of Obesity and Familial Alzheimer's Disease.

There is growing evidence that obesity associated with type 2 diabetes mellitus (T2DM) and aging are risk factors for the development of Alzheimer's disease (AD). However, the molecular mechanisms through which obesity interacts with β-amyloid (Aβ) to promote cognitive decline remains poorly understood. Memantine (MEM), a N-methyl-D-aspartate receptor antagonist, is currently used for the treatment of AD. Nonetheless, few studies have reported its effects on genetic preclinical models of this neurodegenerative disease exacerbated with high-fat diet (HFD)-induced obesity. Therefore, the present research aims to elucidate the effects of MEM on familial AD HFD-induced insulin resistance and learning and memory impairment. Furthermore, it aspires to determine the possible underlying mechanisms that connect AD to T2DM. Wild type and APPswe/PS1dE9 mice were used in this study. The animals were fed with either chow or HFD until 6months of age, and they were treated with MEM-supplemented water (30mg/kg) during the last 12weeks. Our study demonstrates that MEM improves the metabolic consequences produced by HFD in this model of familial AD. Behavioural assessments confirmed that the treatment also improves animals learning abilities and decreases memory loss. Moreover, MEM treatment improves brain insulin signalling upregulating AKT, as well as cyclic adenosine monophosphate response element binding (CREB) expression, and modulates the amyloidogenic pathway, which, in turn, reduced the accumulation of Aβ. Moreover, this drug increases the activation of molecules involved with insulin signalling in the liver, such as insulin receptor substrate 2 (IRS2), which is a key protein regulating hepatic resistance to insulin. These results provide new insight into the role of MEM not only in the occurrence of AD treatment, but also in its potential application on peripheral metabolic disorders where Aβ plays a key role, as is the case of T2DM.

Effect of silencing aquaporin 4 on learning and memory dysfunction in rats with traumatic brain injury

To observe the protein expression related to cognitive and learning memory function, and to investigate the effect of aquaporin 4 (AQP4) silence on learning and memory function in traumatic brain injury (TBI) rats. Ninety-six healthy adult male Wistar rats were divided into groups according to the random number table. (1) Forty-eight rats were divided into sham operation (sham) group, TBI group (by using modified Feeney method), AQP4 RNA interference (RNAi) negative group [TBI+meaningless small interfering RNA (siRNA)-AQP4 liposome solution 10 μL], and AQP4 RNAi group (TBI+siRNA-AQP4 liposome solution 10 μL). In each group, brain tissues of 4 rats were harvested at 1, 6 and 12 hours respectively. The protein expressions of hippocampus AQP4, general control nonderepressible 2 kinase (GCN2), cyclic adenosine monophosphate response element binding protein (CREB) and phosphorylated CREB (p-CREB) were detected by Western Blot. (2) In addition, 48 rats were divided into normal control group (control group), sham group, TBI group and AQP4 RNAi group, brain water content were measured in 6 of them after 12 hours of injury, and 6 were used in Morris water maze test. (1) The protein expressions of hippocampus AQP4 and GCN2 in TBI group were significantly higher than those in sham group, and increased gradually with time with statistical difference at 12 hours (AQP4 protein: 5.03±0.09 vs. 1, GCN2 protein: 4.01±0.13 vs. 1, both P < 0.01); the protein expressions of hippocampus CREB and p-CREB were significantly lower than those in sham group, and decreased gradually with time with statistical difference at 12 hours (CREB protein: 0.38±0.03 vs. 1, p-CREB protein: 0.38±0.03 vs. 1, both P < 0.01). Compared with TBI group, the protein expressions of AQP4 in AQP4 RNAi group was significantly decreased (1 hour: 1.02±0.04 vs. 2.23±0.05, 6 hours: 1.23±0.03 vs. 2.59±0.04, 12 hours: 2.20±0.08 vs. 5.03±0.09, all P < 0.01), but there were no significant difference in the expressions of GCN2, CREB or p-CREB. There was no significant difference in the expression of protein between AQP4 RNAi negative group and TBI group. (2) The brain water content in TBI group was significantly higher than that in control group and sham group [(83.7±0.4)% vs. (76.2±0.2)%, (76.2±0.3)%, both P < 0.01]. The brain water content in AQP4 RNAi group [(78.8±0.3)%] was significantly decreased as compared with that in TBI group (P < 0.01). The latency of Morris water maze test was significantly prolonged in the day 11, 13 and 15 after the injury of the TBI group and AQP4 RNAi group, and the exploration time was significantly shortened. Compared with TBI group, the incubation period of AQP4 RNAi group was significantly shortened at 15 days (s: 60.2±11.1 vs. 62.0±11.5, P < 0.05), and the exploration time was significantly prolonged (s: 37.0±8.5 vs. 32.7±9.2, P < 0.05). The impairment of cognitive and learning memory function in rats after TBI was significantly related to the changes in CREB and GCN2 in cognitive and learning memory function. After RNAi treatment, the cognitive and learning and memory function of rats was not improved obviously, but the brain edema could be alleviated.

Is the Nociception Mechanism Altered in Offspring of Morphine-Abstinent Rats?

To investigate the effect of parental drug abuse on children, nociception, electrophysiological alteration, mRNA expression of opioid receptors, and expression of certain intracellular proteins in offspring of morphine-abstinent rats were studied. Adult male and female animals received water-soluble morphine for 21 days. Ten days after the last morphine administration, animals were placed for mating in 4 groups as follows: healthy (drug naive) female and male, morphine-abstinent female and healthy male, morphine-abstinent male and healthy female, morphine-abstinent male and morphine-abstinent female. Their adult male offspring were tested for nociception, neuronal discharge in nucleus accumbens (NAC) and prefrontal cortex (PFC). Our results showed that nociception in male offspring of all morphine-abstinent parent(s) groups was significantly reduced, compared with the control group. In the offspring of morphine-abstinent parent(s) groups, sensitivity to the antinociceptive effect of morphine was enhanced in chronic as well as in acute phases of the formalin test. Neuronal electrical activity reduced in the offspring of the morphine-exposed parent(s) in NAC as well as PFC regions. Moreover, our findings show that opioid receptors' expressions (µ, κ, and δ) increased in NAC of the litter of morphine-abstinent parent(s), compared with the control group. In addition, the expression of κ receptors was remarkably increased in the PFC in morphine-abstinent parent group, relative to the control group. The phosphorylated levels of extracellular regulated kinase 1/2 and cyclic adenosine monophosphate responsive element binding protein were significantly higher in the offspring of the morphine-abstinent parent(s) than the control group in the NAC. Our results indicated that endogenous opioid is altered in offspring of the morphine-exposed parent(s) and that heritage has a major role. PerspectiveThis study showed that nociception was reduced in offspring of morphine-abstinent rat(s) and also these litters had a low level of neuronal firing rate, and enhanced opioid receptors expression, especially in the NAC. Because these offspring are more sensitive to the analgesic effect of morphine, clinicians should consider this issue to manage the dosage of morphine for treating pain in children with an abstinent parent(s).