Taurochenodeoxycholic acid (TCDCA) is one of the main effective components of bile acid, playing critical roles in apoptosis and immune responses through the TGR5 receptor. In this study, we reveal the interaction between TCDCA and TGR5 receptor in TGR5-knockdown H1299 cells and the regulation of inflammation via the cyclic adenosine monophosphate (cAMP)-protein kinase A (PKA)-cAMP response element binding (CREB) signal pathway in NR8383 macrophages. In TGR5-knockdown H1299 cells, TCDCA significantly activated cAMP level via TGR5 receptor, indicating TCDCA can bind to TGR5; in NR8383 macrophages TCDCA increased cAMP content compared to treatment with the adenylate cyclase (AC) inhibitor SQ22536. Moreover, activated cAMP can significantly enhance gene expression and protein levels of its downstream proteins PKA and CREB compared with groups of inhibitors. Additionally, TCDCA decreased tumour necrosis factor-α (TNF-α), interleukin-1β (IL-1β), IL-6, IL-8 and IL-12 through nuclear factor kappa light chain enhancer of activated B cells (NF-κB) activity. PKA and CREB are primary regulators of anti-inflammatory and immune response. Our results thus demonstrate TCDCA plays an essential anti-inflammatory role via the signaling pathway of cAMP-PKA-CREB induced by TGR5 receptor.
Animals ; Cell Line ; Cyclic AMP/metabolism* ; Cyclic AMP Response Element-Binding Protein/metabolism* ; Cyclic AMP-Dependent Protein Kinases/metabolism* ; Cytokines/metabolism* ; Humans ; Inflammation ; Macrophages ; Rats ; Receptors, G-Protein-Coupled/metabolism* ; Signal Transduction/drug effects* ; Taurochenodeoxycholic Acid/pharmacology*

Lysophosphatidic acid (LPA) is a phospholipid growth factor that acts through G-protein-coupled receptors. Previously, we demonstrated an altered profile of LPA-dependent cAMP content during the aging process of human diploid fibroblasts (HDFs). In attempts to define the molecular events associated with the age-dependent changes in cAMP profiles, we determined the protein kinase A (PKA) activity, phosphorylation of cAMP-response element binding protein (CREB), and the protein expression of CRE-regulatory genes, c-fos and COX-2 in young and senescent HDFs. We observed in senescent cells, an increase in mRNA levels of the catalytic subunit a of PKA and of the major regulatory subunit Ia. Senescence-associated increase of cAMP after LPA treatment correlated well with increased CREB phosphorylation accompanying activation of PKA in senescent cells. In senescent cells, after LPA treatment, the expression of c-fos and COX-2 decreased initially, followed by an increase. In young HDFs, CREB phosphorylation decreased following LPA treatment, and both c-fos and COX-2 protein levels increased rapidly. CRE-luciferase assay revealed higher basal CRE-dependent gene expression in young HDFs compared to senescent HDFs. However, LPA-dependent slope of luciferase increased more rapidly in senescent cells than in young cells, presumably due to an increase of LPA-induced CREB phosphorylation. CRE-dependent luciferase activation was abrogated in the presence of inhibitors of PKC, MEK1, p38MAPK, and PKA, in both young and senescent HDFs. We conclude that these kinase are coactivators of the expression of CRE-responsive genes in LPA-induced HDFs and that their changed activities during the aging process contribute to the final expression level of CRE-responsive genes.
Time Factors ; Protein Kinase Inhibitors/pharmacology ; Phosphorylation ; Male ; Lysophospholipids/*pharmacology ; Luciferases/genetics/metabolism ; Humans ; Gene Expression/drug effects ; Fibroblasts/cytology/*drug effects/metabolism ; Diploidy ; Cyclic AMP-Dependent Protein Kinases/genetics/metabolism ; Cyclic AMP Response Element-Binding Protein/metabolism ; Cyclic AMP/*metabolism ; Cells, Cultured ; Cell Aging/physiology ; Catalytic Domain/genetics

BACKGROUNDHistamine H(3) receptor antagonists have been considered as potential drugs to treat central nervous system diseases. However, whether these drugs can inhibit epileptogenesis remains unclear. This study aimed to investigate the effects of thioperamide, a selective and potent histamine H(3) receptor antagonist, on the seizure development and memory impairment induced by pentylenetetrazole (PTZ)-kindling epilepsy in rats.

METHODSChemical kindling was elicited by repeated intraperitoneal (ip) injections of a subconvulsant dose of PTZ (35 mg/kg) once every 48 hours for 12 times, and seizure activity of kindling was recorded for 30 minutes. Control rats were ip injected with saline instead of PTZ. Morris water maze was used to evaluate the spatial memory. Phosphorylated cyclic adenosine monophosphate response element binding protein (p-CREB) was tested by Western blotting in hippocampus.

RESULTSIntracerebroventricular (icv) injections with thioperamide (10 µg, 20 µg) 30 minutes before every PTZ injections, significantly prolonged the onset of PTZ-kindling and inhibited the seizure stages. PTZ-kindling seizures led to the impairment of spatial memory in rats, and thioperamide ameliorated the impairment of spatial learning and memory. Compared to non-kindling rats, there was a significant decrease in p-CREB level in hippocampus of the PTZ-kindling rats, which was reversed by thioperamide.

CONCLUSIONSThioperamide plays a protective role in seizure development and cognitive impairment of PTZ-induced kindling in rats. The protection of thioperamide in cognitive impairment is possibly associated with the enhancement of CREB-dependent transcription.

Animals ; Anticonvulsants ; pharmacology ; Cyclic AMP Response Element-Binding Protein ; metabolism ; Histamine H3 Antagonists ; pharmacology ; Kindling, Neurologic ; drug effects ; Male ; Memory Disorders ; prevention & control ; Neuroprotective Agents ; pharmacology ; Pentylenetetrazole ; Piperidines ; pharmacology ; Rats ; Rats, Sprague-Dawley ; Seizures ; prevention & control ; Synaptic Transmission

OBJECTIVETo study the effects of methionine and choline on the expression levels of CaMKII and CREB mRNA and proteins in hippocampus of rats exposed to lead.

METHODSMale SD rats were divided into five groups. (1) control group, (2) group exposed to lead+2 by drinking water with 0.40 g/L lead acetate, (3) group exposed to methionine and choline (1:1, 400 mg/kg), (4) group exposed to 0.40 g/L lead acetate plus methionine and choline (1:1, 100 mg/kg), (5) group exposed to 0.40 g/L lead acetate plus methionine and choline (1:1, 400 mg/kg). In 8 weeks after exposure, all rats were killed. Then CREB mRNA and CaMK II mRNA expression levels in hippocampus were detected by real-time PCR, CREB and CaMK II protein expression levels in hippocampus were measured by western blot assay.

RESULTSThe expression levels (0.743 ± 0.185 and 0.729 ± 0.199) of CaMKII mRNA and CREB mRNA in the hippocampus of lead group were significantly lower than those (0.950 ± 0.238 and 0.901 ± 0.232) of control group (P < 0.05), also the expression levels (0.271 ± 0.045 and 0.212 ± 0.058) of CREB protein and pCREB protein in the hippocampus of lead group were significantly lower than those (0.319 ± 0.058 and 0.506 ± 0.125) of control group (P < 0.05). The expression levels (1.014 ± 0.210 and 1.126 ± 0.379) of CaMKII mRNA and the expression levels (1.029 ± 0.335 and 0.932 ± 0.251) of CREB mRNA in the hippocampus of 2 groups exposed to lead acetate plus methionine and choline were significantly higher than those of lead group (P < 0.05). The expression levels (0.407 ± 0.951 and 0.563 ± 0.178) of CREB protein and pCREB protein in the hippocampus of group exposed to lead acetate plus 400 mg/kg methionine and choline were significantly higher than those of lead group (P < 0.05).

CONCLUSIONMethionine and choline could decrease the inhibition effects of lead on the expression of CaMKII and CREB mRNA or CREB and pCREB proteins in the hippocampus of rats.

Animals ; Calcium-Calmodulin-Dependent Protein Kinase Type 2 ; metabolism ; Choline ; pharmacology ; Cyclic AMP Response Element-Binding Protein ; metabolism ; Hippocampus ; drug effects ; metabolism ; Lead ; toxicity ; Male ; Methionine ; pharmacology ; RNA, Messenger ; genetics ; Rats ; Rats, Sprague-Dawley

Transcription factor cyclic AMP response element-binding protein (CREB) in embryonic cortical neurons is an important modulator of Brain-derived neurotrophic factor (BDNF) induced gene expression. Meanwhile, our early researches have indicated that BDNF possesses neuroprotective role for hypoxic neurons against hypoxia. In order todisclose whether the neuroprotective role of BDNF for embryonic rat cortical neurons against hypoxia is fulfilled via nucleoprotein CREB phosphorylation, we used western blotting method to detect the expression of CREB and phosphorylated CREB in experimental groups (with BDNF) and hypoxic control group (without BDNF) with the time changes of exposure to hypoxia. Results indicated that hypoxia and BDNF both could induce phosphorylation of CREB in embryonic cortical neurons. Phosphorylation of CREB in experimental group (with BDNF) was much higher than that in hypoxic control group at the same time points (P<0.01). The expression of phosphorylated CREB reached the highest level at the first hour after being exposed to hypoxia in experimental groups, then phosphorylated CREB decreased slowly and remained at the level for much longer time in experimental groups than in control group. The total amount of CREB in embryonic cortical neurons at the first 0-3 hours after being exposed to hypoxia in experimental groups were the same as that in hypoxic control group. CREB decreased more quickly in hypoxic control group at 5-6 hours after hypoxia. This in vitro research demonstrates that BDNF plays its neuroprotective role for embryonic rat cortical neurons against hypoxia via CREB phosphorylation.
Animals ; Brain-Derived Neurotrophic Factor ; chemistry ; pharmacology ; Cell Hypoxia ; Cells, Cultured ; Cerebral Cortex ; cytology ; Cyclic AMP Response Element-Binding Protein ; chemistry ; Embryo, Mammalian ; Neurons ; cytology ; Neuroprotective Agents ; chemistry ; pharmacology ; Phosphorylation ; Rats

OBJECTIVETo investigate the changes in CREB (cAMP response element binding protein) in hippocampus, PFC (prefrontal cortex) and NAc (nucleus accumbens) during three phases of morphine induced CPP (conditioned place preference) in rats, and to elucidate the role of CREB during the progress of conditioned place preference.

METHODSMorphine induced CPP acquisition, extinction and drug primed reinstatement model was established, and CREB expression in each brain area was measured by Western Blot methods.

RESULTSEight alternating injections of morphine (10 mg/kg) induced CPP, and 8 d saline extinction training that extinguished CPP. CPP was reinstated following a priming injection of morphine (2.5 mg/kg). During the phases of CPP acquisition and reinstatement, the level of CREB expression was significantly changed in different brain areas.

CONCLUSIONIt was proved that CPP model can be used as an effective tool to investigate the mechanisms underlying drug-induced reinstatement of drug seeking after extinction, and that morphine induced CPP and drug primed reinstatement may involve activation of the transcription factor CREB in several brain areas, suggesting that the CREB and its target gene regulation pathway may mediate the basic mechanism underlying opioid dependence and its drug seeking behavior.

Analgesics, Opioid ; pharmacology ; Animals ; Blotting, Western ; Conditioning (Psychology) ; Conditioning, Operant ; drug effects ; Cyclic AMP Response Element-Binding Protein ; biosynthesis ; Hippocampus ; metabolism ; Male ; Morphine ; pharmacology ; Nucleus Accumbens ; metabolism ; Prefrontal Cortex ; metabolism ; Rats ; Rats, Sprague-Dawley ; Time Factors

OBJECTIVE: To investigate the effect of miR-203/CREB1 signaling regulation mediated by DNA methylation on the proliferation, invasion and apoptosis of multiple myeloma (MM) cells. METHODS: The methylation level of miR-203 in the RPMI 8226 cells was detected by bisulfite sequcucing polymerase chain reaction (BSP). The mRNA expression of miR-203 was measured by quantitative real-time polymerase chain reaction. RPMI 8226 cells were treated with DNA methyltransferase inhibitor 5-Aza-2'-deoxycytidine (5-Aza-CdR). The miR-203 mimic in MM cell line RPMI 8226 was transfected to establish overexpressed miR-203 cell. The proliferation, invasion ability and apoptosis of RPMI 8226 cell was detected by CCK-8 assay, Transwell, and flow cytometry, respectively. The targeting relationship between miR-203 and CREB1 was verified by double luciferase report assay. Western blot was used to detect the expression of CREB1 protein. RESULTS: Hypermethylation of miR-203 promoter region and low expression level of miR-203 mRNA were detected in the RPMI 8226 cells, which showed that demethylation could induce the expression of miR-203. The proliferation and invasion ability of RPMI 8226 cells after treated by 5-Aza-CdR were inhibited, and showed statistical significance as compared with blank control group (both P<0.05)，while the apoptosis rate was promoted (P<0.05). The proliferation, invasion ability and apoptosis of overexpressed miR-203 were the same as the demethylation group. Double luciferase report assay confirmed that CREB1 was the direct target of miR-203. The protein level of CREB1 was inhibited by demethylation and showed statistical significance as compared with control group (P<0.05). CONCLUSION MiR-203 targeting CREB1 mediated by DNA methylation leads to maintain the malignant biological behaviors of MM cells.
Apoptosis ; Azacitidine/pharmacology* ; Cell Line, Tumor ; Cell Proliferation ; Cyclic AMP Response Element-Binding Protein/pharmacology* ; DNA Methylation ; Gene Expression Regulation, Neoplastic ; Humans ; MicroRNAs/metabolism* ; Multiple Myeloma/genetics* ; RNA, Messenger/metabolism*

OBJECTIVETo study the effects of kaixinsan on behavior and expression of p-CREB in hippocampus of the chronic stress rats.

METHODThe male Wistar rats which gained the similar scores by Open-field test were selected, then the depression model rat was produced by separation and chronic unpredictable mild stress. Open-field test was performed to detect the behavior of rats and immunohistochemistry was used to observe the changes of p-CREB expression in hippocampus.

RESULTOn the 22nd day, the body weight and sacchar-intake of the depression model rats were all lower than those of the normal rats and the body weight and sacchar-intake of the rats treated by drugs were higher compared with model rats (P < 0.01). The depressive behavior in kaixinsan 4 g x kg(-1) group was significantly improved compared with the model group, the crossing scores and rearing scores were all increased (P < 0.01) and the expression of p-CREB in CA1, CA3 and DG in hippocampus was higher than that in the model group (P < 0.05 and P < 0.01).

CONCLUSIONKaixinsan might improve depressive behavior by increasing expression of p-CREB in CA1, CA3 and DG in hippocampus of the chronic stress rats.

Animals ; Antidepressive Agents ; pharmacology ; Behavior, Animal ; drug effects ; Cyclic AMP Response Element-Binding Protein ; metabolism ; Depression ; etiology ; physiopathology ; Drug Combinations ; Drugs, Chinese Herbal ; isolation & purification ; pharmacology ; Hippocampus ; metabolism ; Male ; Plants, Medicinal ; chemistry ; Random Allocation ; Rats ; Rats, Wistar ; Stress, Psychological ; complications

BACKGROUNDThe CKLF-like MARVEL transmembrane domain-containing family (CMTM) is a novel family of proteins linking chemokines and TM4SF. Different members exhibit diverse biological functions. In this study, the effect of intracellular CMTM2 on regulating human immunodeficiency virus type-1 (HIV-1) transcription was evaluated.

METHODSThe effects of CMTM2 on regulating full-length HIV-1 provirus and the HIV-1 long terminal repeat (LTR)-directed transcription were assessed by luciferase assay. Transcription factor assays, using the luciferase reporter plasmids of AP-1, CRE, and NF-κB were conducted to explore the signaling pathway(s) that may be regulated by CMTM2. The potential relationship between CMTM2 and the transcription factor AP-1 was further analyzed by Western blotting analyses to investigate the effect of CMTM2 on PMA-induced ERK1/2 phosphorylation.

RESULTSThe results from the current study revealed that CMTM2 acts as a negative regulator of HIV-1 transcription. CMTM2 exerted a suppressive action on both full-length HIV-1 provirus and HIV-1 LTR-directed transcription. Transcription factor assays showed that CMTM2 selectively inhibited basal AP-1 and CREB activity. Co-expression of HIV-1 Tat, a potent AP-1 and CREB activator, can not reverse CMTM2-mediated AP-1 and CREB inhibition, suggesting a potent and specific effect of CMTM2 on negatively regulating these two signaling pathways.

CONCLUSIONIntracellular CMTM2 can negatively regulate HIV-1 transcription, at least in part, by targeting the AP-1 and CREB pathways. Exploring the mechanisms further may lead to new ways to control HIV-1 replication.

Chemokines ; physiology ; Cyclic AMP Response Element-Binding Protein ; antagonists & inhibitors ; HIV Long Terminal Repeat ; HIV-1 ; genetics ; Humans ; Intracellular Space ; metabolism ; Jurkat Cells ; MARVEL Domain-Containing Proteins ; Tetradecanoylphorbol Acetate ; pharmacology ; Transcription Factor AP-1 ; antagonists & inhibitors ; Transcription, Genetic ; U937 Cells

To define the molecular basis of ethanol dependence, changes in the phosphorylation of cAMP response element binding protein (CREB) in the nucleus accumbens of rats after acute and chronic ethanol administration were detected using immunohistochemistry. The results demonstrate that the expression of phospho-CREB (p-CREB) protein in the rat nucleus accumbens significantly increased after 15 min of acute ethanol exposure, reaching a peak at 30 min after ethanol administration. The increment remained after 1 or 6 h of ethanol exposure compared to the control rats. In contrast, chronic intake of ethanol solution obviously decreased the expression of p-CREB protein compared to the control rats. The decrement remained 24 h or 72 h after ethanol withdrawal, and returned to the control levels after 7 d of ethanol withdrawal. The results suggest that an acute ethanol administration led to an increase in the phosphorylation of CREB in the nucleus accumbens, but chronic ethanol administration produced a decrement, which is possibly one of the molecular mechanisms of alcohol dependence.
Alcoholism ; metabolism ; physiopathology ; Animals ; Cyclic AMP Response Element-Binding Protein ; chemistry ; metabolism ; Ethanol ; pharmacology ; Male ; Nucleus Accumbens ; metabolism ; Phosphorylation ; Rats ; Rats, Sprague-Dawley ; Substance Withdrawal Syndrome ; metabolism ; physiopathology ; Substance-Related Disorders ; metabolism ; physiopathology