Mechanism of Shaoyaotang in Regulating Water Metabolism and Intestinal Epithelial Permeability in Ulcerative Colitis Through cAMP/PKA/CREB Signaling Pathway / 中国实验方剂学杂志

ObjectiveTo investigate the role of cyclic adenosine monophosphate （cAMP）/protein kinase A （PKA）/cAMP-response element binding protein （CREB） signaling pathway in water metabolism and intestinal epithelial permeability in ulcerative colitis （UC） and the intervention mechanism of Shaoyaotang based on the theory of large intestine governing fluids. MethodSixty male SD rats were divided into blank group， model group， mesalazine group （0.42 g·kg-1）， Shaoyaotang low-dose group （11.1 g·kg-1）， Shaoyaotang medium-dose group （22.2 g·kg-1） and Shaoyaotang high-dose group （44.4 g·kg-1）， with 10 in each group. The UC rat model of internal retention of dampness-heat was established by compound factors. The blank group and the model group were given normal saline （ig）. The mesalazine group was given mesalazine （ig）， and Shaoyaotang low-， medium- and high-dose groups were administrated with corresponding doses of Shaoyaotang （ig）. The treatment lasted for 14 days. The diarrhea score and fecal moisture content of rats in each group were observed. The contents of diamine oxidase （DAO） and D-lactic acid in plasma were detected by enzyme-linked immunosorbent assay （ELISA）. The protein expressions of aquaporin （AQP）8， AQP4， ZO-1 and Occludin in colon tissues were detected by immunohistochemistry， while those of cAMP， PKA and CREB in colon tissues were determined by Western blot. ResultCompared with the normal group， the model group had elevated diarrhea score and fecal moisten content （P<0.01）， increased contents of DAO and D-lactic acid in plasma （P<0.01） and decreased protein expressions of ZO-1， Occludin， AQP8， AQP4， cAMP， PKA and CREB in colon （P<0.01）. Compared with the conditions in the model group， the contents of DAO and D-lactic acid in plasma in each administration groups were lower （P<0.01）， while the protein expressions of ZO-1， Occludin， AQP8， AQP4， cAMP， PKA and CREB in colon were higher （P<0.01）. ConclusionShaoyaotang alleviates the diarrhea in UC， probably through activating cAMP/PKA/CREB signaling pathway， up-regulating expressions of AQPs， enhancing tight junctions in intestinal epithelium and thus improving the water metabolism in colon and the intestinal mucosal permeability.

Mechanism of Modified Shenqiwan in Relieving Renal Interstitial Fibrosis in Diabetic Mice Based on GSK-3β/CREB Pathway / 中国实验方剂学杂志

ObjectiveTo observe the effects of modified Shenqiwan on renal function and fibrosis in diabetic nephropathy mice and explore the underlying mechanism based on the glycogen synthase kinase-3β （GSK-3β）/cyclic adenosine monophosphate （cAMP） response element-binding protein （CREB） signaling pathway. MethodFifty male db/db mice and 10 db/m mice were used in this study. The fifty db/db mice were randomly divided into model group， irbesartan group， and low-， medium-， and high-dose modified Shenqiwan groups. The 10 db/m mice were assigned to the normal group. The mice in the low-， medium-， and high-dose modified Shenqiwan groups were administered with modified Shenqiwan in the dosage form of suspension of Chinese medicinal granules by gavage， those in the irbesartan group were given irbesartan suspension by gavage， and those in the normal and model groups were given distilled water of equal volume by gavage. The intervention lasted for 12 weeks. The blood glucose levels， urine albumin-to-creatinine ratio （UACR）， and the protein expression levels of GSK-3β， CREB， transforming growth factor-β1 （TGF-β1）， E-cadherin， Vimentin， fibronectin （FN）， plasminogen activator inhibitor-1 （PAI-1）， and Collagen type Ⅳ （Coll Ⅳ） in the mouse kidneys were recorded before and after treatment. The extent of renal pathological damage was also observed. ResultCompared with the normal group， the model group showed significant increases in blood glucose levels， UACR levels， and the protein expression levels of GSK-3β， TGF-β1， E-cadherin， Vimentin， FN， PAI-1， and Coll Ⅳ in the kidneys （P<0.05）， decreased protein expression level of CREB （P<0.05）， and severe renal pathological damage. Compared with the model group， the low-， medium-， and high-dose modified Shenqiwan groups and the irbesartan group showed varying degrees of decreases in blood glucose levels， UACR levels， and the protein expression levels of GSK-3β， TGF-β1， E-cadherin， Vimentin， FN， PAI-1， and Coll Ⅳ in the kidneys （P<0.05）， increased expression level of CREB protein （P<0.05）， and improved renal pathological damage. ConclusionModified Shenqiwan can effectively reduce blood glucose levels， improve renal function， and alleviate fibrosis， and the mechanism of action is related to the inhibition of the GSK-3β/CREB signaling pathway.

Buyang Huanwutang Treats Diabetic Peripheral Neuropathy via Mitochondrial Transport in Rats / 中国实验方剂学杂志

ObjectiveTo investigate the mechanism of Buyang Huanwutang in treating diabetic peripheral neuropathy （DPN） via mitochondrial transport. MethodDiabetes in SD rats was induced by a high-carbohydrate/high-fat diet and intraperitoneal injection of streptozotocin （STZ）. The 45 diabetic rats were randomly assigned into a DPN group， an alpha-lipoic acid （60 mg·kg-1·d-1） group， and a Buyang Huanwutang （15 g·kg-1·d-1） group， with 15 rats in each group. Fifteen normal SD rats were fed with the standard diet and set as the control group. The rats were administrated with corresponding drugs by gavage for 12 weeks. The paw withdraw threshold （PWT） and motor nerve conduction velocity （MNCV） were measured at the end of medication， and the sciatic nerve and the bilateral dorsal root ganglia of L4-5 were collected. The injury model of NSC34 cells was established by treating with 50 mmol·L-1 glucose and 250 μmol·L-1 sodium palmitate. The NSC34 cells were then randomly assigned into a blank （10% blank serum） group， a DPN （10% blank serum） group， an apha-lipoic acid （10% apha-lipoic acid-containing serum） group， a Buyang Huanwutang （10% Buyang Huanwutang-containing serum） group， and a Buyang Huanwutang + Compound C （CC） （10% Buyang Huanwutang-containing serum + 10 μmol·L-1 CC） group. The cell intervention lasted for 24 h. The immunofluorescence method， immunohistochemistry， and Western blot were employed to determine the expression levels of phosphorylated adenosine monophosphate-activated protein kinase （p-AMPK）， phosphorylated cAMP-response element binding protein （p-CREB）， kinesin family member 5A （KIF5A）， and dynein cytoplasmic 1 intermediate chain 2 （DYNC1I2）. ResultCompared with the control group， the DPN group of rats showed increased fasting blood glucose （P<0.01）， decreased MNCV and PWT （P<0.01）， down-regulated expression of KIF5A， p-AMPK/AMPK， and p-CREB/CREB （P<0.01）， and up-regulated expression of DYNC1I2 （P<0.01）. Compared with the DPN group， drug intervention groups showed increased MNCV and PWT （P<0.01）， up-regulated expression of KIF5A， p-AMPK/AMPK， and p-CREB/CREB （P<0.05， P<0.01）， and down-regulated expression of DYNC1I2 （P<0.05， P<0.01）. The Buyang Huanwutang group had higher levels of MNCV and KIF5A （P<0.05） and lower level of DYNC1I2 （P<0.01） than the apha-lipoic acid group. Compared with the blank group， the DPN group of NSC34 cells showed decreased levels of KIF5A， p-AMPK/AMPK， and p-CREB/CREB （P<0.01） and increased level of DYNC1I2 （P<0.01）. The apha-lipoic acid group and Buyang Huanwutang group had higher levels of KIF5A， p-AMPK/AMPK， and p-CREB/CREB （P<0.05， P<0.01） and lower level of DYNC1I2 （P<0.01） in NSC34 cells than the DPN group. Buyang Huanwutang group had higher KIF5A level （P<0.05） in NSC34 cells than the apha-lipoic acid group. Moreover， the Buyang Huanwutang + CC group had lower levels of KIF5A， DYNC1I2， p-AMPK/AMPK， and p-CREB/CREB （P<0.01） in NSC34 cells than the Buyang Huanwutang group. ConclusionBuyang Huanwutang may regulate mitochondrial anterograde transport via the AMPK/CREB pathway to prevent and treat DPN.

Total Flavones of Spatholobi Caulis Regulate Hippocampal Neuroplasticity in Depressed Rats Through CREB/BDNF Pathway / 中国实验方剂学杂志

ObjectiveTo investigate the effect and mechanism of total flavones of Spatholobi Caulis （TFSC） against depression in rats. MethodThe fifty KM mice were randomly divided into the normal group and high-， medium-， and low-dose （1， 0.5， 0.25 g·kg-1） TFSC groups and gavaged with the corresponding drugs for 12 successive days. One hour after the last administration， the immobility time in forced swimming test and tail suspension test was recorded. The SD rats were randomly divided into the normal group， model group， fluoxetine （5 mg·kg-1） group， and high- and low-dose （1， 0.25 g·kg-1） TFSC groups. Following the exposure of rats to two different kinds of stimuli daily for inducing chronic unpredictable stress， they were administered with the corresponding drugs for 21 d. After the experiment， the levels of serum neurotransmitters and inflammatory factors in rats were detected by enzyme-linked immunosorbent assay （ELISA）. The changes in hippocampal neurons of rats were observed by hematoxylin-eosin （HE） and Nissl staining. The mRNA expression levels of nuclear factor-κB （NF-κB） and tumor necrosis factor-α （TNF-α） in the hippocampus of rats were detected by real-time fluorescence quantitative polymerase chain reaction （Real-time PCR）， and the protein expression levels of cAMP-response element binding protein （CREB）， phosphorylated CREB （p-CREB）， and brain-derived neurotrophic factor （BDNF） in hippocampal tissues by Western blot. ResultCompared with the normal group， TFSC significantly shortened the immobility time of mice in tail suspension and swimming tests （P<0.05）. Compared with the normal group， the model group exhibited reduced sucrose intake and wilderness activity （P<0.01）， decreased 5-HT， DA， NE （P<0.05， P<0.01）， MAO， IL-6， TNF-α （P<0.05， P<0.01）， damaged neurons， increased mRNA levels of TNF-α and NF-κB （P<0.01）， and down-regulated BDNF and CREB protein expression （P<0.05）. Compared with the model group， TFSC significantly enhanced sucrose intake and wilderness activity of rats （P<0.05）， increased the serum 5-HT， DA and NE （P<0.05， P<0.01）， and decreased the serum MAO， IL-6， and TNF-α （P<0.05， P<0.01） as well as NF-κB and TNF-α mRNA expression （P<0.01）， up-regulated the protein expression levels of BDNF and CREB （P<0.01）， and improved the pathological symptoms of hippocampus. ConclusionTFSC improved the hippocampal neurons of rats via CREB/BDNF signaling pathway and reduced depressive pathological damage， thus relieving depression.

Da Chaihutang Protects Liver Mitochondrial Function of Nutritionally Obese Rats via CREB/PGC-1α Pathway / 中国实验方剂学杂志

Objective:To observe the effects of Da Chaihutang on Cyclic adenosine monophosphate （cAMP）-response element binding protein （CREB）/peroxisome proliferator-activated receptor-gamma coactivator-1 alpha （PGC-1<italic>α</italic>） pathway in nutritionally obese rats and the protective mechanism on liver mitochondria. Method:A total of 120 8-week-old male SD rats were randomly divided into a control group （<italic>n</italic>=20） and an experimental group （<italic>n</italic>=100）. The rats in the control group were fed on a normal diet， while those in the experimental group were administered with a high-fat feed. Successfully modeled rats were randomly divided into a model group， a positive drug （metformin） group， and low-， medium- and high-dose Da Chaihutang groups （4.25， 8.5， and 17 g∙kg^-1， respectively）， with 20 rats in each group. After treatment with Da Chaihutang， the body weight， Lee's index， liver mitochondrial membrane potential and mitochondrial ultrastructure， PGC-1<italic>α </italic>expression and CREB phosphorylation of each group were measured and compared. Result:Compared with the control group， the model group showed increased body weight and Lee's index （<italic>P</italic><0.01）， whereas decreased mitochondrial membrane potential， PGC-1<italic>α</italic> expression， and CREB phosphorylation level （<italic>P</italic><0.01）. As compared with the model group， Da Chaihutang significantly reduced the body weight and Lee's index of obese rats （<italic>P</italic><0.05， <italic>P</italic><0.01）， enhanced liver mitochondrial membrane potential （<italic>P</italic><0.05， <italic>P</italic><0.01） to protect the integrity of mitochondrial structure， up-regulated PGC-1<italic>α</italic> expression and promoted CREB phosphorylation （<italic>P</italic><0.05， <italic>P</italic><0.01）. Conclusion:Da Chaihutang protects the structure and function of mitochondria and inhibits weight gain in obese rats by activating the CREB/PGC-1<italic>α</italic> pathway.

Effect of Jianpi Bufei Prescription on cAMP/PKA/CREB Signaling Pathway in Juvenile Asthma Rats / 中国实验方剂学杂志

Objective:To investigate the effect of Jianpi Bufei prescription （JPBFP） on airway inflammation， airway hyperresponsiveness （AHR）， and cyclic adenosine monophosphate （cAMP） signaling pathway activity in ovalbumin （OVA）-sensitized and challenged juvenile asthma rats. Method:Seventy-five male SD rats were randomly divided into a blank group （<italic>n</italic>=15） and an experimental group （<italic>n</italic>=60）. The rats in the experimental group were sensitized by aluminum hydroxide gel containing 0.2% OVA and stimulated by aerosol inhalation of normal saline containing 1% OVA to induce an asthma model， followed by assignment into the following groups： a model group （<italic>n</italic>=15）， a JPBFP group （<italic>n</italic>=15， 8.37 g·kg^-1·d^-1）， an aminophylline group （<italic>n</italic>=15， 40 mg·kg^-1·d^-1）， and a dexamethasone group （<italic>n</italic>=15， 0.1 mg·kg^-1·d^-1）. AHR was detected by the pulmonary function analyzer， changes in inflammatory cells by white blood cell （WBC） count and differential blood count in bronchoalveolar lavage fluid （BALF）， and pathological changes of lung tissues by hematoxylin-eosin （HE）， Masson， and periodic acid-schiff （PAS） staining. The interleukin （IL）-4， IL-5， IL-13， interferon （IFN）-<italic>γ</italic>， and tumor necrosis factor （TNF）-<italic>α</italic> levels in serum and the cAMP level in plasma were tested by the enzyme-linked immunosorbent assay （ELISA）. Protein kinase A （PKA） expression in lung tissues was detected by immunohistochemistry. The cAMP-response element-binding protein （CREB） mRNA and protein expression in lung tissues was detected by the real-time fluorescence quantitative polymerase chain reaction （Real-time PCR） and Western blot. Result:Compared with the blank group， the model group showed increased lung resistance， decreased pulmonary compliance （<italic>P</italic><0.05）， elevated WBC count and proportion of eosinophils in BALF （<italic>P</italic><0.05）， up-regulated levels of IL-4， IL-5， IL-13， and TNF-<italic>α</italic> in peripheral blood， declining IFN-<italic>γ</italic> level （<italic>P</italic><0.01）， severe pathological changes of lung tissues， dwindled cAMP， and down-regulated PKA and CREB expression （<italic>P</italic><0.01）. Compared with the model group， JPBFP inhibited AHR， reduced WBC count and proportion of eosinophils in BALF and lung resistance （<italic>P</italic><0.05）， improved pathological changes of lung tissues， increased pulmonary compliance， and up-regulated cAMP in serum and PKA and CREB expression in lung tissues （<italic>P</italic><0.01）. Conclusion:JPBFP can improve AHR， inhibit airway inflammation， and alleviate lung injury in asthma rats. Its mechanism may be related to the up-regulation of the activity of the cAMP/PKA/CREB signaling pathway.

Effect of electroacupuncture on expression of CREB and its ability to bind to synaptic proteins in amygdala and hippocampus of rats with post-traumatic stress disorder / 针刺研究

OBJECTIVE: To observe the effect of electroacupuncture (EA) on the expression of cAMP-response element binding protein (CREB, a key protein for BDNF-TrkB signaling) and it's blinding ability to synaptic key protein in the amygdala and hippocampus of rats with post-traumatic stress disorder (PTSD), so as to lay a foundation for further study of the interaction mechanism between BDNF-TrkB signaling and synaptic plasticity. METHODS: Twenty-four male SD rats were randomly divided into blank, model and electroacupuncture (EA) groups, with 8 rats in each group. The PTSD model was established by psychological stress (bondage) and physiological stress (forced swimming and anesthesia). After modeling, EA (2 Hz/100 Hz, 1 mA) was applied to "Baihui"(GV20) "Shenting"(GB24) and bilateral "Shenshu"(BL23) for 20 min, once daily for 21 days. The behavioral changes (spontaneous locomotor within 30 min and contextual fear conditioning tests in 7 days) were detected by using a spontaneous locomotor detection box, and a conditioned fear response test chamber, respectively. The expression of CREB was detected by immunohistochemistry and Western blot, separately. The binding abilities of CREB to synaptic proteins (post synaptic density 95 [PSD95], synaptophysin [SYN] and growth-associated protein 43 [GAP43]) were verified by chromatin-immunoprecipitation (CHIP) technique. RESULTS: After modeling, the spontaneous locomotor distance, the expression levels of CREB and the binding ability of CREB to PSD95 protein in the amygdala and hippocampus were significantly decreased (P0.05). CONCLUSION: EA can improve the motor activity in PTSD rats, which may be associated with its effect in increasing the binding ability of CREB to the synaptic key protein PSD95 to regulate the interaction between the synaptic plasticity and BDNF-TrkB signaling pathway of the amygdala and hippocampus.

Effect of Wendantang-containing Serum on CREB Gene Silencing Hippocampal Neuron Apoptosis and BDNF/TrkB/CREB Signaling Pathway / 中国实验方剂学杂志

Objective:To investigate the effect of Wendantang on cyclic adenosine monophosphate （cAMP）-response element binding protein（CREB） gene silencing hippocampal cell activity， apoptosis and signal pathway of brain-derived neurotrophic factor/protomyosin related receptor kinase B/adenosine cyclophosphate effector binding protein （BDNF/TrkB/CREB）. Method:Wendantang-containing serum was prepared. Animal grouping： SD male rats were randomly divided into high， medium， low-dose groups， clozapine group and normal saline group， with 10 rats in each group， while 15 rats for the normal group. Dosage： 20 mL·kg-1 normal saline was given to normal group N， clozapine 0.02 g·kg-1 was given to dozapine group X， while high， medium and low-dose Wendantang groups were respectively given the same amount of Wendantang concentrated crude drug， with concentrations of 2， 1 and 0.5 g·mL-1 respectively once a day for 8 days continuously， and then blood was taken from femoral artery， and centrifuged for 15 min at 5 000 r·min-1. Supernatant was taken， inactivated， stored at -80 ℃ for standby. The CREB gene silenced hippocampal neuron cell line was constructed through transfection of liposomes into hippocampal cells， and Real-time fluorescence quantitative polymerase chain reaction （Real-time PCR） was used to verify the effect of small interfering RNA （siRNA） transcription. The mRNA expressions of BDNF， TrkB， CREB and CaMKⅡ in normal hippocampal cells and CREB gene silenced hippocampal cells were measured. Result:Compared with normal group， the apoptosis of the normal gene silencing group was significantly increased （P<0.01）， compared with the normal gene silencing group， the apoptosis of each group was significantly reduced （P<0.01）. As for the mRNA expressions of BDNF， TrkB， CREB and CaMKⅡ， compared with the normal group， the mRNA expression of CREB， BDNF in the normal gene silencing group was significantly decreased （P<0.01）. Compared with the normal gene silencing group， the mRNA expression of BDNF in each administration group was highly increased （P<0.01）， but with no statistically significant difference between TrkB and CaMKⅡ groups. Conclusion:The Wendantang-containing serum could improve the mRNA expression of BDNF， protect hippocampal neurons and prevent cognitive impairment of schizophrenia by regulating BDNF/TrkB/CREB signal pathway.

Effect of electrical stimulation at auricular points combined with sound masking on the expression of CREB, BDNF and TrkB in the auditory cortex of tinnitus rats / 中国针灸

OBJECTIVE@#To explore the effect of electrical stimulation at auricular points (EAS) combined with sound masking on the expression of cAMP-response element binding protein (CREB), brain-derived neurotrophic factor (BDNF) and tyrosine receptor kinase B (TrkB) in the auditory cortex of tinnitus rats.@*METHODS@#A total of 27 adult male SD rats were randomly divided into a control group, a model group and an EAS group. The rats in the model group and the EAS group were intervened with intraperitoneal injection of sodium salicylate to induce tinnitus model, while the rats in the control group were intervened with injection of 0.9% NaCl solution. After the model was successfully established, the rats in the EAS group were treated with electrical stimulation at "Shenmen" (TF) and "Yidan" (CO), combined with sound masking; the treatment was given once a day for 15 days. The gap prepulse inhibition of acoustic startle (GPIAS) and prepulse inhibition (PPI) testing were performed using the acoustic startle reflex starter package for rats. The expression of BDNF, TrkB, CREB and p-CREB in the auditory cortex of each group were measured with Western Blot analysis.@*RESULTS@#① Compared with the control group, the GPIAS values in 12 kHz, 16 kHz, 20 kHz and 28 kHz were significantly decreased in the model group (all 0.05).@*CONCLUSION@#EAS could improve the GPIAS values of high-frequency background sound in tinnitus rats, which may be related with the upregulation of the BDNF/TrkB/CREB signaling pathway in the auditory cortex, leading to the reversion of the maladaptive plasticity.

Phosphodiesterase 4 as a target for the development of novel drugs against cognitive impairment:research advances / 国际药学研究杂志

Alzheimer′s disease(AD)is one of the most common causes of cognitive impairment.“Aβhypothesis”and“tau protein aggregation hypothesis”are two representative hypotheses in relation to AD pathology. But recently,therapeutic strategy target?ing on reducing Aβdeposition failed in clinical trials. On the other hand,as the phosphorylation of tau protein is regulated by multiple upstream kinases,inhibition of a single kinase usually cannot effectively suppress the aggregation of the tau. While blocking multiple kinases at the same time will produce serious side effects. Currently,targeting on Aβand tau protein get into awkward situations. In view of this,researchers are looking for new drug targets for improving cognitive function. Phosphodiesterase 4(PDE4 4)is an enzyme responsible for the hydrolysis of cAMP in the body. There are four subtypes for PDE4,and PDE4A,B and D are highly expressed in the central nervous system. Inhibition of PDE4 causes activation of cAMP/PKA/CREB/BDNF signal pathway,which is beneficial for the strengthening and consolidation of learning and memory. This review will focus on the most recent evidence regarding the role of PDE4 in learning and memory.

Insights into the regulation of TNF-a production in human mononuclear cells: the effects of non-specific phosphodiesterase inhibition

OBJECTIVE: The objective of this study was to determine the effect of nonspecific phosphodiesterase inhibition on transcription factor activation and tumor necrosis factor-alpha (TNF-a) production in lipopolysaccharide (LPS)-stimulated human mononuclear cells. INTRODUCTION: The production of TNF-a following LPS stimulation is one of the key steps in bacterial sepsis and inflammation. The mechanism by which phosphodiesterase inhibition alters TNF-a production in the presence of LPS remains unclear. METHODS: Human mononuclear cells were stimulated with LPS (1 µg/mL), in the presence and absence of Pentoxifylline (PTX; 20 mM), a nonspecific phosphodiesterase inhibitor. Western blotting of phosphorylated cytoplasmic I-kBa, nuclear factor-kB p65 (NF-kB), and nuclear cAMP-response element binding protein (CREB) was performed. DNA binding of NF-kB and CREB was verified by electrophoretic mobility shift assay. TNF-a levels were determined in the supernatant of stimulated cells in the presence and absence Protein kinase A inhibition by an enzyme-linked immunosorbent assay (ELISA). RESULTS: PTX was demonstrated to significantly reduce cytoplasmic I-kBa phosphorylation, nuclear p65 phosphorylation, and the DNA binding activity of NF-kB. In contrast, PTX markedly enhanced the phosphorylation and DNA binding activity of CREB. Cells concomitantly treated with PTX and LPS secreted similar levels of TNF-a in the presence and absence Protein kinase A inhibition. DISCUSSION: The increased level of cAMP that results from phosphodiesterase inhibition affects cytoplasmic and nuclear events, resulting in the attenuation of NF-kB and the activation of CREB transcriptional DNA binding through pathways that are partially Protein kinase A-independent. CONCLUSION: PTX-mediated phosphodiesterase inhibition occurs partially through a Protein kinase A-independent pathway and may serve as a useful tool in the attenuation of LPS-induced inflammation.

Protein kinase A mediates microglial activation induced by plasminogen and gangliosides

In the injured brain, microglia is known to be activated and produce proinflammatory mediators such as interleukin-1beta (IL-1beta), tumor necrosis factor-alpha (TNF-alpha) and inducible nitric oxide synthase (iNOS). We investigated the role of protein kinase A (PKA) in microglial activation by both plasminogen and gangliosides in rat primary microglia and in the BV2 immortalized murine microglial cell line. Both plasminogen and gangliosides induced IL-1beta, TNF-alpha and iNOS mRNA expression, and that this expression was inhibited by the addition of the PKA inhibitors, KT5720 and H89. Both plasminogen and gangliosides activated PKA and increased the DNA binding activity of the cAMP response element- binding protein (CREB). Furthermore, KT5720 and H89 reduced the DNA binding activities of CREB and NF-kappaB in plasminogen-treated cells. These results suggest that PKA plays an important role in plasminogen and gangliosides- induced microglial activation.