Alzheimer's disease (AD) is the most common form of dementia among the elderly, characterized by amyloid plaques, neurofibrillary tangles, and neuroinflammation in the brain, as well as impaired cognitive behaviors. A sex difference in the prevalence of AD has been noted, while sex differences in the cerebral pathology and relevant molecular mechanisms are not well clarified. In the present study, we systematically investigated the sex differences in pathological characteristics and cognitive behavior in 12-month-old male and female APP/PS1/tau triple-transgenic AD mice (3×Tg-AD mice) and examined the molecular mechanisms. We found that female 3×Tg-AD mice displayed more prominent amyloid plaques, neurofibrillary tangles, neuroinflammation, and spatial cognitive deficits than male 3×Tg-AD mice. Furthermore, the expression levels of hippocampal protein kinase A-cAMP response element-binding protein (PKA-CREB) and p38-mitogen-activated protein kinases (MAPK) also showed sex difference in the AD mice, with a significant increase in the levels of p-PKA/p-CREB and a decrease in the p-p38 in female, but not male, 3×Tg-AD mice. We suggest that an estrogen deficiency-induced PKA-CREB-MAPK signaling disorder in 12-month-old female 3×Tg-AD mice might be involved in the serious pathological and cognitive damage in these mice. Therefore, sex differences should be taken into account in investigating AD biomarkers and related target molecules, and estrogen supplementation or PKA-CREB-MAPK stabilization could be beneficial in relieving the pathological damage in AD and improving the cognitive behavior of reproductively-senescent females.
Alzheimer Disease ; metabolism ; pathology ; psychology ; Amyloid beta-Protein Precursor ; genetics ; metabolism ; Animals ; Cyclic AMP Response Element-Binding Protein ; metabolism ; Cyclic AMP-Dependent Protein Kinases ; metabolism ; Disease Models, Animal ; Female ; Hippocampus ; metabolism ; pathology ; Humans ; Inflammation ; metabolism ; pathology ; psychology ; Male ; Maze Learning ; physiology ; Mice, Inbred C57BL ; Mice, Transgenic ; Neurofibrillary Tangles ; metabolism ; pathology ; Plaque, Amyloid ; metabolism ; pathology ; psychology ; Presenilin-1 ; genetics ; metabolism ; Sex Characteristics ; Spatial Memory ; physiology ; p38 Mitogen-Activated Protein Kinases ; metabolism ; tau Proteins ; genetics ; metabolism

OBJECTIVETo study the effects of Zuogui Pill (, ZGP) and Yougui Pill (, YGP) on the expressions of brain-derived neurotrophic factor (BDNF) and cyclic adenosine monophosphate (cAMP)/protein kinase A (PKA) signaling of axonal regeneration in the Lewis rats with experimental autoimmune encephalomyelitis (EAE), in order to explore the possible mechanism of ZGP and YGP on promoting axonal regeneration.

METHODSThe rats were randomly divided into normal control (NC), model (MO), prednisone acetate (PA), ZGP and YGP groups. The EAE model of rat was established by injecting antigen containing myelin basic protein (MBP)68-86. The brain and spinal cord were harvested on the 14th and 28th day post-immunization (PI), the protein and mRNA expression of BDNF and PKA in the brain and spinal cord of rats were detected by Western blot analysis and real-time quantitative polymerase chain reaction (PCR), and the cAMP levels were detected by using enzyme-immunoassay method.

RESULTS(1) On the 28th day PI, the mRNA expression of BDNF in brain white matter and spinal cord of rats in ZGP and YGP groups were up-regulated, especially in YGP group (P<0.05 or P<0.01). (2) On the 14th day PI, the cAMP levels in brain white matters significantly increased in PA and YGP groups compared with MO group (P<0.05 or P<0.01), and the cAMP level in YGP group was higher than that in ZGP group (P<0.05). The cAMP level in spinal cord also significantly increased in YGP group compared with MO, PA and ZGP groups, respectively (P<0.01). (3) On the 14th day PI, the PKA expression in spinal cord of rats in ZGP group was significantly decreased compared with MO and YGP groups, respectively (P<0.05). (4) On the 28th day PI, there was a positive correlation between cAMP and PKA expression in the brain white matter of YGP rats.

CONCLUSIONSThe results suggest that ZGP and YGP may promote axonal regeneration by modulating cAMP/PKA signal transduction pathway, but the targets of molecular mechanism of ZGP may be different from those of YGP.

Animals ; Axons ; drug effects ; pathology ; Brain ; drug effects ; metabolism ; pathology ; Brain-Derived Neurotrophic Factor ; genetics ; metabolism ; Cyclic AMP ; metabolism ; Cyclic AMP-Dependent Protein Kinases ; genetics ; metabolism ; Disease Models, Animal ; Drugs, Chinese Herbal ; pharmacology ; therapeutic use ; Encephalomyelitis, Autoimmune, Experimental ; drug therapy ; enzymology ; genetics ; Female ; Gene Expression Regulation ; drug effects ; Nerve Regeneration ; drug effects ; genetics ; RNA, Messenger ; genetics ; metabolism ; Rats ; Rats, Inbred Lew ; Signal Transduction ; drug effects ; genetics ; Spinal Cord ; drug effects ; metabolism ; pathology ; Tablets

OBJECTIVEEffects of ginsenoside Rb1, Rg1 and Re on neurotrophic factor signal transduction pathway using liposome-mediated transfection of eukaryotic cells approach.

METHODThe injury model was established by treating SH-SY5Y cells with 0.6 mmol x L(-1) of corticosterone (CORT) by 24 h. SH-SY5Y cell were pretreated with CORT for 30 min followed by co-treated with 120,60 and 20 micromol x L(-1) of Rb1, 120, 80 and 40 micromol x L(-1) of Rg1 and 120, 80 and 40 micromol x L(-1) of Re for 24 h. Cells viability was determined by Cell Counting Kit (CCK) assay. CREB expressing Luciferase reporter gene was constructed and transfected with plasmid containing hRaf, hcAMP, hAkt, hCaMK gene into human embryonic kidney (HEK293) cells using liposornal transfection reagent lipofection 2000. The expression of CREB before and after it addion of Rb1, Rg1 and Re was examined by Luc assay system and Western blotting.

RESULTCompared with normal control group, CORT significantly decreased the viability of SH-SY5Y cells to 67.21% (P < 0.01). CCK results show that Rb1 (60 micromol x L(-1)), Rg1 (80 micromol x L(-1)) and Re (80 micromol x L(-1)) on SH-SY5Y cells have significant protective effect (P < 0.01). Lucassay and Western blotting results show that the gene and protein levels of CREB increased significantly through the pathway of Raf and Akt with Rb1 and Rg1 (P < 0.01), Re can increase significantly the gene and protein levels of CREB through the pathway of Raf and CaMK II.

CONCLUSIONRb1, Rg1 and Re protects SH-SY5Y cells from CORT-induced damage and the neuroprotective mechanism may be associated with the Raf-CREB, Akt-CREB and CaMK II -CREB pathways.

Calcium-Calmodulin-Dependent Protein Kinase Type 2 ; genetics ; metabolism ; Cell Line ; Cell Survival ; drug effects ; Cyclic AMP Response Element-Binding Protein ; genetics ; metabolism ; Drugs, Chinese Herbal ; pharmacology ; Genes, Reporter ; Ginsenosides ; pharmacology ; Humans ; Panax ; chemistry ; Proto-Oncogene Proteins c-akt ; genetics ; metabolism ; Signal Transduction ; drug effects ; raf Kinases ; genetics ; metabolism

OBJECTIVETo observe the effects of Mongolian pharmaceutical Betel shisanwei ingredients pill on AC-cAMP-PKA signal transduction pathways in hippocampus and prefrontal cortex of depressive rats.

METHODSixty male Wistar rats were randomly divided into six groups according to the sugar consumption test (10 rats in each group), normal control group,model group,fluoxetine group (3.3 mg x kg(-1)) and low dose, medium dose and high dose group (0.25, 0.5, 1 g x kg(-1)) of Betel shisanwei ingredients pill. Except the normal control,the other groups were treated with the chronic unpredictable mild stress stimulation combined with lonely raising for 28 days. 10 mL x kg(-1) of drugs were given to each rat once daily,continuously for 28 days. The AC activity of the hippocampus and prefrontal cortex were determined by radiation immunity analysis (RIA), while cAMP and PKA quantity were determinated by Enzyme-linked immunosorbent (ELISA).

RESULTThe AC activity, cAMP and PKA quantity of hippocampus and prefrontal of mouse model of Chronic stress depression decreased significantly than those of control group (P < 0.05 or P < 0.01). However, the AC activity, cAMP and PKA quantity of rat hippocampus and prefrontal cortex in the fluoxetine group and the Mongolian pharmaceutical Betel shisanwei ingredients pill group indecreased significantly than those of model group (P < 0.01 or P < 0.05). Especially for the high dose group of Mongolian pharmaceutical Betel shisanwei ingredients pill.

CONCLUSIONThe AC-cAMP-PKA signal transduction pathways in hippocampus and prefrontal cortex of depression model of rats is down-regulated, whereas Mongolian pharmaceutical Betel shisanwei ingredients pill could up-regulated it to resist depression.

Adenylyl Cyclases ; genetics ; metabolism ; Animals ; Cyclic AMP ; metabolism ; Cyclic AMP-Dependent Protein Kinases ; genetics ; metabolism ; Depression ; drug therapy ; genetics ; metabolism ; Drugs, Chinese Herbal ; administration & dosage ; Hippocampus ; drug effects ; metabolism ; Humans ; Male ; Mice ; Prefrontal Cortex ; drug effects ; metabolism ; Rats ; Rats, Wistar ; Signal Transduction ; drug effects

To further test whether protein kinase A (PKA) can affect the mitotic cell cycle, one-cell stage mouse embryos at S phase (22 h after hCG injection) were incubated in M16 medium containing various concentrations of H-89, a PKA inhibitor. With increasing concentrations of H-89 (0-50 μmol/L), the G(2) phase of eggs was decreased and the cleavage rate was accelerated. A concentration of 40 μmol/L H-89 led to all of the mouse eggs entering the M phase of mitosis. Furthermore, to study the role of PKA in regulating the phosphorylation status of S149 and S321 sites of cell division cycle 25B (CDC25B) on one-cell stage fertilized mouse eggs, pBSK-CDC25B-WT, pBSK-CDC25B-S149A, pBSK-CDC25B-S321A and pBSK-CDC25B-S149A/S321A were transcribed into mRNAs in vitro, then mRNAs were microinjected into S phase of mouse fertilized eggs and cultured in M16 medium pretreated with H-89. Then, the cleavage of fertilized eggs, maturation promoting factor (MPF) activity and phosphorylation status of CDC2-Tyr15 were observed. In the presence of 40 μmol/L H-89, the cleavage rate of fertilized eggs in CDC25B-S/A-mRNAs and CDC25B-WT-mRNA injected groups was significantly higher than that in the control groups, and the peak of MPF activity appeared in the CDC25B-S/A-mRNAs and CDC25B-WT-mRNA injected groups earlier than that in the control groups. CDC2-Tyr15 phosphorylation state was consistent with MPF activity. In conclusion, the present study suggests that PKA regulates the early development of mouse embryos by phosphorylation of S149 and S321 of CDC25B, which plays an important role in the regulation of G(2)/M transition in the mitotic cell cycle of fertilized mouse eggs.
Animals ; Cyclic AMP-Dependent Protein Kinases ; genetics ; physiology ; Embryonic Development ; physiology ; Female ; Male ; Mice ; Microinjections ; Mitosis ; drug effects ; Phosphorylation ; Serine ; genetics ; metabolism ; Zygote ; cytology ; growth & development ; cdc25 Phosphatases ; genetics ; metabolism

BACKGROUNDEnhanced and prolonged expression of connective tissue growth factor (CTGF) is associated with kidney fibrosis. Parathyroid hormone (PTH) is involved in the genesis of disturbed calcium/phosphate metabolism and ostitis fibrosa in renal failure. PTH activated mitogen-activated protein kinase (MAPK) signaling pathway is present in renal tubular cells. The aim of this study was to identify the mechanism how the signal is transduced to result in extracellular signal-regulated protein kinase (ERK) activation, leading to upregulation of CTGF.

METHODSThe levels of CTGF mRNA and protein in human kidney proximal tubular cells (HK-2) treated with PTH in the presence or absence of the MAPK inhibitor PD98059 were analyzed by quantitative real-time polymerase chain reaction (RT-PCR) and immunoblotting assay. The activation of the CTGF promoter in HK-2 cells was determined by the dual-luciferase assay. The effects of the protein kinase A (PKA) activator 8-Br-cAMP and protein kinase C (PKC) activator phorbol 12-myristate 13-acetate (PMA) on MAPK phosphorylation, and the effects of the PKA inhibitor H89 and PKC inhibitor calphostin C on MAPK phosphorylation and CTGF expression were detected by immunoblotting assay.

RESULTSPD98059 inhibited the PTH stimulated expression of CTGF, which strongly suggested that the MAPK signaling pathway plays an important role in the PTH-induced CTGF upregulation in renal tubular cells. A PKA activator as well as PKC activators induced MAPK phosphorylation, and both PKA and PKC inhibitors antagonized PTH-induced MAPK phosphorylation and CTGF expression.

CONCLUSIONCTGF expression is upregulated by PTH through a PKC/PKA-ERK-dependent pathway.

Cells, Cultured ; Connective Tissue Growth Factor ; genetics ; physiology ; Cyclic AMP-Dependent Protein Kinases ; physiology ; Extracellular Signal-Regulated MAP Kinases ; physiology ; Fibrosis ; Flavonoids ; pharmacology ; Humans ; Kidney Tubules, Proximal ; metabolism ; pathology ; MAP Kinase Signaling System ; Mitogen-Activated Protein Kinases ; physiology ; Parathyroid Hormone ; pharmacology ; Phosphorylation ; Protein Kinase C ; physiology

OBJECTIVETo investigate the effect and mechanism of emodin for regulating aquapoin-2 (AQP2) in NRK cells cultured in vitro.

METHODSExperiments on NRK cells cultured with alpha-DMEM medium in vitro were conducted in two steps. (1) Cells were randomly divided into 4 groups: the control group, and the three emodin treated groups treated with different dosages of emodin (5, 10 and 20 mg/L) respectively. After 24 h treatment, the location of AQP2 was decided by indirect immunofluorescene, and the AQP2 protein and mRNA expression levels were detected by Western blot and semiquantive RT-PCR. (2) Cells were randomly divided into 4 groups, the control group, and the three treated groups treated respectively with 10 mg/L 8-Bromo-cAMP, 20 mg/L emodin, and 20 mg/L emodin +10 mg/L 8-Bromo-cAMP. The activity of protein kinase A (PKA) in NRK cells after 24 h treatment was determined with non-radioactive detecting method.

RESULTSAQP2 was located at the cell membrane of NRK cells. Western blot and semiquantitive RT-PCR found that AQP2 protein and mRNA expressions were significantly decreased in NRK cells of groups treated by 10 mg/L and 20 mg/L emodin (P < 0.05). PKA activity determination showed significantly decreased phosphorylation level of PKA in NRK cells of groups treated with 20 mg/L emodin group (P < 0.05).

CONCLUSIONEmodin can inhibit the genetic transcription and the translation of AQP2 gene in NRK cells, which demonstrates that the change of AQP2 expression regulated by emodin may be correlated with the diuresis effect of rhubarb, and it is likely that the regulation is going through PKA signal pathway.

Animals ; Aquaporin 2 ; genetics ; metabolism ; Cell Line ; Cyclic AMP-Dependent Protein Kinases ; metabolism ; Emodin ; pharmacology ; Kidney ; cytology ; metabolism ; RNA, Messenger ; genetics ; metabolism ; Rats ; Signal Transduction ; drug effects

The aim of this project is to establish a GLP-1 signaling pathway targeted cell model, for screening the new class of GLP-1 receptor agonists as anti-diabetic candidates. Firstly construct a recombined plasmid with multi-copied specific response element (RIP-CRE) regulated by GLP-1 signaling pathway and E-GFP reporter gene. Transient transfect this recombined plasmid into islet cell NIT-1, then detect the responsibility of transfected cell to GLP-1 analogue, Exendin 4. For secondly, use stable transfection and monocloning cell culture to obtain a GLP-1 signaling-specific cell line. It indicates that this cell model can response to Exendin 4, which response can be completely inhibited by GLP-1 receptor antagonist, Exendin 9-39, further showing GLP-1 receptor specific activity with a cAMP-PKA-independently mechanism. Establishment of this novel cell model can be used in high-throughput drug screening of peptides or small molecular GLP-1 analogues.
Animals ; Cell Line ; Cyclic AMP Response Element Modulator ; pharmacology ; Cyclic AMP-Dependent Protein Kinases ; antagonists & inhibitors ; Drug Delivery Systems ; Drug Evaluation, Preclinical ; Genes, Reporter ; Glucagon-Like Peptide-1 Receptor ; Green Fluorescent Proteins ; metabolism ; Hypoglycemic Agents ; agonists ; antagonists & inhibitors ; metabolism ; Islets of Langerhans ; cytology ; drug effects ; metabolism ; Isoquinolines ; pharmacology ; Peptide Fragments ; pharmacology ; Peptides ; antagonists & inhibitors ; pharmacology ; Plasmids ; Rats ; Receptors, Glucagon ; agonists ; antagonists & inhibitors ; genetics ; metabolism ; Recombinant Proteins ; genetics ; metabolism ; Signal Transduction ; Sulfonamides ; pharmacology ; Transfection ; Venoms ; pharmacology

OBJECTIVEThis 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).

METHODSPregnant 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).

RESULTSPKA, 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).

CONCLUSIONSTaurine 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.

Animals ; Brain ; drug effects ; Cyclic AMP Response Element-Binding Protein ; genetics ; physiology ; Cyclic AMP-Dependent Protein Kinases ; genetics ; physiology ; Female ; Fetal Growth Retardation ; metabolism ; Fetus ; drug effects ; Glial Cell Line-Derived Neurotrophic Factor ; genetics ; Male ; Pregnancy ; RNA, Messenger ; analysis ; Rats ; Rats, Sprague-Dawley ; Signal Transduction ; drug effects ; Taurine ; pharmacology

Previously we demonstrated that ATP released from LPS-activated microglia induced IL-10 expression in a process involving P2 receptors, in an autocrine fashion. Therefore, in the present study we sought to determine which subtype of P2 receptor was responsible for the modulation of IL-10 expression in ATP-stimulated microglia. We found that the patterns of IL-10 production were dose-dependent (1, 10, 100, 1,000 micrometer) and bell-shaped. The concentrations of ATP, ATP-gammaS, ADP, and ADP-beta S that showed maximal IL-10 release were 100, 10, 100, and 100 micrometer respectively. The rank order of agonist potency for IL-10 production was 2'-3'-O-(4-benzoyl)-benzoyl ATP (BzATP) = dATP > 2-methylthio-ADP (2-meSADP). On the other hand, 2-methylthio-ATP (2-meSATP), alpha,beta-methylene ATP (alpha,beta-meATP), UTP, and UDP did not induce the release of IL-10 from microglia. Further, we obtained evidence of crosstalk between P2 receptors, in a situation where intracellular Ca2+ release and/or cAMP-activated PKA were the main contributors to extracellular ATP-(or ADP)-mediated IL-10 expression, and IL-10 production was down- regulated by either MRS2179 (a P2Y1 antagonist) or 5'-AMPS (a P2Y11 antagonist), indicating that both the P2Y1 and P2Y11 receptors are major receptors involved in IL-10 expression. In addition, we found that inhibition of IL-10 production by high concentrations of ATP-gammaS (100 micrometer) was restored by TNP-ATP (an antagonist of the P2X1, P2X3, and P2X4 receptors), and that IL-10 production by 2-meSADP was restored by 2meSAMP (a P2Y12 receptor antagonist) or pertusis toxin (PTX; a Gi protein inhibitor), indicating that the P2X1, P2X3, P2X4 receptor group, or the P2Y12 receptor, negatively modulate the P2Y11 receptor or the P2Y1 receptor, respectively.
Adenosine Diphosphate/analogs & derivatives/pharmacology ; Adenosine Triphosphate/analogs & derivatives/*pharmacology ; Adenylate Cyclase/antagonists & inhibitors ; Animals ; Calcium/metabolism ; Chelating Agents/pharmacology ; Cyclic AMP-Dependent Protein Kinases/antagonists & inhibitors ; Enzyme Inhibitors/pharmacology ; Extracellular Space/drug effects/*metabolism ; Gene Expression Regulation/drug effects ; Interleukin-10/*biosynthesis ; Microglia/*drug effects/enzymology/*metabolism ; RNA, Messenger/genetics/metabolism ; Rats ; Rats, Sprague-Dawley ; Receptor Cross-Talk/*drug effects ; Receptors, Purinergic P2/agonists/antagonists & inhibitors/genetics/*metabolism ; Thionucleotides/pharmacology