Metabotropic glutamate receptors(mGluRs)in epileptogenesis:an update on abnormal mGluRs signaling and its therapeutic implications

Epilepsy is a neurological disorder characterized by high morbidity,high recurrence,and drug resistance.Enhanced signaling through the excitatory neurotransmitter glutamate is intricately associated with epilepsy.Metabotropic glutamate receptors(mGluRs)are G protein-coupled receptors activated by glutamate and are key regulators of neuronal and synaptic plasticity.Dysregulated mGluR signaling has been associated with various neurological disorders,and numerous studies have shown a close relationship between mGluRs expression/activity and the development of epilepsy.In this review,we first introduce the three groups of mGluRs and their associated signaling pathways.Then,we detail how these receptors influence epilepsy by describing the signaling cascades triggered by their activation and their neuroprotective or detrimental roles in epileptogenesis.In addition,strategies for pharmacological manipulation of these receptors during the treatment of epilepsy in experimental studies is also summarized.We hope that this review will provide a foundation for future studies on the development of mGluR-targeted antiepileptic drugs.

Netrin-1 signaling pathway mechanisms in neurodegenerative diseases

Netrin-1 and its receptors play crucial roles in inducing axonal growth and neuronal migration during neuronal development.Their profound impacts then extend into adulthood to encompass the maintenance of neuronal survival and synaptic function.Increasing amounts of evidence highlight several key points:(1)Diminished Netrin-1 levels exacerbate pathological progression in animal models of Alzheimer’s disease and Parkinson’s disease,and potentially,similar alterations occur in humans.(2)Genetic mutations of Netrin-1 receptors increase an individuals’susceptibility to neurodegenerative disorders.(3)Therapeutic approaches targeting Netrin-1 and its receptors offer the benefits of enhancing memory and motor function.(4)Netrin-1 and its receptors show genetic and epigenetic alterations in a variety of cancers.These findings provide compelling evidence that Netrin-1 and its receptors are crucial targets in neurodegenerative diseases.Through a comprehensive review of Netrin-1 signaling pathways,our objective is to uncover potential therapeutic avenues for neurodegenerative disorders.

Adenosine 2A receptor contributes to the facilitation of postinfectious irritable bowel syndrome by γδ T cells via the PKA/CREB/NF-κB signaling pathway

BACKGROUND Immunological dysfunction-induced low-grade inflammation is regarded as one of the predominant pathogenetic mechanisms in post-infectious irritable bowel syndrome(PI-IBS).γδT cells play a crucial role in innate and adaptive immunity.Adenosine receptors expressed on the surface ofγδT cells participate in intestinal inflammation and immunity regulation.AIM To investigate the role ofγδT cell regulated by adenosine 2A receptor(A2AR)in PI-IBS.METHODS The PI-IBS mouse model has been established with Trichinella spiralis(T.spiralis)infection.The intestinal A2AR and A2AR inγδT cells were detected by immunohistochemistry,and the inflammatory cytokines were measured by western blot.The role of A2AR on the isolatedγδT cells,including proliferation,apoptosis,and cytokine production,were evaluated in vitro.Their A2AR expression was measured by western blot and reverse transcription polymerase chain reaction(RT-PCR).The animals were administered with A2AR agonist,or A2AR antagonist.Besides,γδT cells were also injected back into the animals,and the parameters described above were examined,as well as the clinical features.Furthermore,the A2AR-associated signaling pathway molecules were assessed by western blot and RT-PCR.RESULTS PI-IBS mice exhibited elevated ATP content and A2AR expression(P<0.05),and suppression of A2AR enhanced PI-IBS clinical characteristics,indicated by the abdominal withdrawal reflex and colon transportation test.PI-IBS was associated with an increase in intestinal T cells,and cytokine levels of interleukin-1(IL-1),IL-6,IL-17A,and interferon-α(IFN-α).Also,γδT cells expressed A2AR in vitro and generated IL-1,IL-6,IL-17A,and IFN-α,which can be controlled by A2AR agonist and antagonist.Mechanistic studies demonstrated that the A2AR antagonist improved the function ofγδT cells through the PKA/CREB/NF-κB signaling pathway.CONCLUSION Our results revealed that A2AR contributes to the facilitation of PI-IBS by regulating the function ofγδT cells via the PKA/CREB/NF-κB signaling pathway.

Gamma-aminobutyric acid A receptors in Alzheimer＇s disease： highly localized remodeling of a complex and diverse signaling pathway

Alzheimer＇s disease （AD）, the predominant form of dementia, is a chronic, incurable neurodegenerative disorder presenting with symptoms includ- ing progressive memory loss and disturbed emotional state. It has been estimated that dementia affects over 47 million people worldwide （Prince et al., 2015）, and with 60-80% of cases attributable to AD.

Yemazhui(Herba Eupatorii Lindleyani)ameliorates lipopolysaccharide-induced acute lung injury via modulation of the toll-like receptor 4/nuclear factor kappa-B/nod-like receptor family pyrin domain-containing 3 protein signaling pathway and intestinal flor

OBJECTIVE:To investigate the impact of Yemazhui(Herba Eupatorii Lindleyani,HEL)against lipopolysaccharide(LPS)-induced acute lung injury(ALI)and explore its underlying mechanism in vivo.METHODS:The chemical constituents of HEL were analyzed by ultra-high performance liquid chromatographyquadrupole time-of-flight mass spectrometry method.Then,HEL was found to suppress LPS-induced ALI in vivo.Six-week-old male Sprague-Dawley rats were randomly divided into 6 groups:control,LPS,Dexamethasone(Dex),HEL low dose 6 g/kg(HEL-L),HEL medium dose 18 g/kg(HEL-M)and HEL high dose 54 g/kg(HEL-H)groups.The model rats were intratracheally injected with 3 mg/kg LPS to establish an ALI model.Leukocyte counts,lung wet/dry weight ratio,as well as myeloperoxidase(MPO)activity were determined followed by the detection with hematoxylin and eosin staining,enzyme linked immunosorbent assay,quantitative real time polymerase chain reaction,western blotting,immunohistochemistry,and immunofluorescence.Besides,to explore the effect of HEL on ALI-mediated intestinal flora,we performed 16s rRNA sequencing analysis of intestinal contents.RESULTS:HEL attenuated LPS-induced inflammation in lung tissue and intestinal flora disturbance.Mechanism study indicated that HEL suppressed the lung coefficient and wet/dry weight ratio of LPS-induced ALI in rats,inhibited leukocytes exudation and MPO activity,and improved the pathological injury of lung tissue.In addition,HEL reduced the expression of tumor necrosis factoralpha,interleukin-1beta(IL-1β)and interleukin-6(IL-6)in bronchoalveolar lavage fluid and serum,and inhibited nuclear displacement of nuclear factor kappa-B p65(NF-κBp65).And 18 g/kg HEL also reduced the expression levels of toll-like receptor 4(TLR4),myeloid differentiation factor 88,NF-κBp65,phosphorylated inhibitor kappa B alpha(phospho-IκBα),nod-like receptor family pyrin domain-containing 3 protein(NLRP3),IL-1β,and interleukin-18(IL-18)in lung tissue,and regulated intestinal flora disturbance.CONCLUSIONS:In summary,our findings revealed that HEL has a protective effect on LPS-induced ALI in rats,and its mechanism may be related to inhibiting TLR4/NF-κB/NLRP3 signaling pathway and improving intestinal flora disturbance.

Microwave Exposure Impairs Synaptic Plasticity in the Rat Hippocampus and PC12 Cells through Over-activation of the NMDA Receptor Signaling Pathway

Objective The aim of this study is to investigate whether microwave exposure would affect the N-methyI-D-aspartate receptor （NMDAR） signaling pathway to establish whether this plays a role in synaptic plasticity impairment. Methods 48 male Wistar rats were exposed to 30 mW/cm^2 microwave for 10 min every other day for three times. Hippocampal structure was observed through H＆E staining and transmission electron microscope. PC12 cells were exposed to 30 mW/cm^2 microwave for 5 min and the synapse morphology was visualized with scanning electron microscope and atomic force microscope. The release of amino acid neurotransmitters and calcium influx were detected. The expressions of several key NMDAR signaling molecules were evaluated. Results Microwave exposure caused injury in rat hippocampal structure and PC12 cells, especially the structure and quantity of synapses. The ratio of glutamic acid and gamma-aminobutyric acid neurotransmitters was increased and the intracellular calcium level was elevated in PC12 cells. A significant change in NMDAR subunits （NR1, NR2A, and NR2B） and related signaling molecules （CaZ＋/calmodulin-dependent kinase II gamma and phosphorylated cAMP-response element binding protein） were examined. Conclusion 30 mW/cm^2 microwave exposure resulted in alterations of synaptic structure, amino acid neurotransmitter release and calcium influx. NMDAR signaling molecules were closely associated with impaired synaptic plasticity.

B cell receptor signaling pathway involved in benign lymphoepithelial lesions of the lacrimal gland

AIM：To detect the expression of B cell receptor signaling pathway（BCRSP） in lacrimal gland benign lymphoepithelial lesions（LGBLEL）.METHODS：Gene microarray was used to compare whole-genome expression in lacrimal gland tissues from LGBLEL patients to tissues from orbital cavernous hemangioma（control tissues）. Expression of BCRSP was confirmed by polymerase chain reaction（PCR） and immunohistochemistry. RESULTS：The expression of 22 genes of the BCRSP increased significantly in LGBLEL patients. PCR analysis showed that CD22, CR2, and BTK were all highly expressed in LGBLEL tissues. Immunohistochemical analysis showed that CR2 protein was present in LGBLEL, but CD22 and BTK proteins were negative. CR2, CD22, and BTK were not observed in the orbital cavernous hemangiomas with either PCR or immunohistochemistry. CONCLUSION：BCRSP might be involved in the pathogenesis of LGBLEL.

MiRNA-122 Promotes Ischemia-Reperfusion Injury after Lung Transplantation via the Toll-like Receptor Signaling Pathway

Objective:MiRNAs have been recently implicated in the pathogenesis of ischemia-reperfusion(IR)injury.This study aimed to investigate the miRNA expression profiles,in the early stages after lung transplantation(LT)and to study the involvement of the Toll-like receptor(TLR)signaling pathway in lung IR injury following LT.Methods:We established the left LT model in mice and selected the miRNA-122 as a research target.The mice were injected with a miRNA-122-specific inhibitor,following which pathological changes in the lung tissue were studied using different lung injury indicators.In addition,we performed deep sequencing of transplanted lung tissues to identify differentially expressed(DE)miRNAs and their target genes.These target genes were used to further perform gene ontology(GO)enrichment analysis and Kyoto Encyclopedia of Genes and Genomes(KEGG)analysis.Results:A total of 12 DE miRNAs were selected,and 2476 target genes were identified.The GO enrichment analysis predicted 6063 terms,and the KEGG analysis predicted 1554 biological pathways.Compared with the control group,inhibiting the expression of miRNA-122 significantly reduced the lung injury and lung wet/dry ratio(P<0.05).In addition,the activity of myeloperoxidase and the expression levels of tumor necrosis factor-alpha and TLR2/4 were decreased(P<0.05);whereas the expression of interleukin-10 was increased(P<0.05).Furthermore,the inhibition of miRNA-122 suppressed the IR injury-induced activation of the TLR signaling pathway.Conclusion:Our findings showed the differential expression of several miRNAs in the early inflammatory response following LT.Of these,miRNA-122 promoted IR injury following LT,whereas its inhibition prevented IR injury in a TLR-dependent manner.

Function of the CaMKII-ryanodine receptor signaling pathway in rabbits with left ventricular hypertrophy and triggered ventricular arrhythmia

BACKGROUND:Calcium calmodulin-dependent kinase II(CaMKII) can be more active in patients with left ventricular hypertrophy(LVH),which in turn causes phosphorylation of ryanodine receptors,resulting in inactivation and the instability of intracellular calcium homeostasis.The present study aimed to determine the effect of CaMKII-ryanodine receptor pathway signaling in rabbits with left ventricular hypertrophy and triggered ventricular arrhythmia.METHODS:Forty New Zealand rabbits were randomized into four groups(10 per group):sham group,LVH group,KN-93 group(LVH+KN-93),and ryanodine group(LVH+ryanodine).Rabbits in the LVH,KN-93,and ryanodine groups were used to establish a left ventricular hypertrophy model by the coarctation of the abdominal aorta,while those in the sham group did not undergo the coarctation.After eight weeks,action potentials(APs) were recorded simultaneously in the endocardium and epicardium,and a transmural electrocardiogram(ECG) was also recorded in the rabbit left ventricular wedge model.Drugs were administered to the animals in the KN-93 and ryanodine groups,and the frequency of triggered APs and ventricular tachycardia was recorded after the rabbits were given isoprenaline(1 μmol/L) and high-frequency stimulation.RESULTS:The frequency(animals/group) of triggered APs was 0/10 in the sham group,10/10 in the LVH group,4/10 in the KN-93 group,and 1/10 in the ryanodine group.The frequencies of ventricular tachycardia were 0/10,9/10,3/10,and 1/10,respectively.The frequencies of polymorphic ventricular tachycardia or ventricular fibrillation were 0/10,7/10,2/10,and 1/10,respectively.The frequencies of triggered ventricular arrhythmias in the KN-93 and ryanodine groups were much lower than those in the LVH group(P<0.05).CONCLUSIONS:KN-93 and ryanodine can effectively reduce the occurrence of triggered ventricular arrhythmia in rabbits with LVH.The CaMKII-ryanodine signaling pathway can be used as a new means of treating ventricular arrhythmia.

Effects of (-)-Epigallocatechin gallate on some protein factors involved in the epidermal growth factor receptor signaling pathway

（-）-Epigallocatechin gallate （EGCG）, a major polyphenolic constituent of green tea, can inhibit activity of specific receptor tyrosine kinases （RTKs） and related downstream signal transduction pathways, resulting in the control of unwanted cell proliferation. The epidermal growth factor receptor （EGFR） signaling pathway is one of the most important pathways that regulates growth, survival,proliferation and differentiation in mammalian cells. This review addresses the effects of EGCG on some protein factors involved in the EGFR signaling pathway in a direct or indirect manner. Based on our understanding of the interaction between EGCG and these factors, and based on their structures, EGCG could be used as a lead compound for designing and synthesizing novel drugs with significant biological activity.

Research progress on the regulation of androgen receptor signaling pathway in the treatment of prostate cancer by traditional Chinese medicine monomers

The prevalence of prostate cancer in males worldwide is increasing every year.Androgen and androgen receptor drive the development of prostate cancer and are important targets for the treatment of prostate cancer.A growing number of reports indicate that the traditional Chinese medicine has a clear advantage in the prevention and treatment of prostate cancer.This article provides an overview of the in vitro and in vivo studies of different traditional Chinese medicine monomers acting on the androgen receptor-signaling pathway in prostate cancer.

Fibroblast growth factor receptor signaling as therapeutic targets in gastric cancer

Fibroblast growth factor receptors(FGFRs) regulate a variety of cellular functions, from embryogenesis to adult tissue homeostasis. FGFR signaling also plays significant roles in the proliferation, invasion, and survival of several types of tumor cells. FGFR-induced alterations, including gene amplification, chromosomal translocation, and mutations, have been shown to be associated with the tumor initiation and progression of gastric cancer, especially in diffuse-type cancers. Therefore, the FGFR signaling pathway might be one of the therapeutic targets in gastric cancer. This review aims to provide an overview of the role of FGFR signaling in tumorigenesis, tumor progression, proliferation, and chemoresistance. We also discuss the accumulating evidence that demonstrates the effectiveness of using clinical therapeutic agents to inhibit FGFR signaling for the treatment of gastric cancer.

Oxymatrine reduces neuroinflammation in rat brain A signaling pathway

Cerebral neuroinflammation models were established by injecting 10μg lipopolysaccharide into the hippocampus of male Sprague-Dawley rats. The rats were treated with an intraperitoneal injection of 120, 90, or 60 mg/kg oxymatrine daily for three days prior to the lipopolysaccharide injection. Twenty-four hours after model induction, the hippocampus was analyzed by real-time quantitative PCR, and the cerebral cortex was analyzed by enzyme-linked immunosorbent assay and western blot assay. The results of the enzyme-linked immunosorbent assay and the real-time quantitative PCR showed that the secretion and mRNA expression of the pro-inflammatory cytokines interleukin-113 and tumor necrosis factor-a were significantly decreased in the hippocampus and cerebral cortex of model rats treated with oxymatrine. Western blot assay and real-time quantitative PCR analysis indicated that toll-like receptor 4 mRNA and protein expression were significantly decreased in the groups receiving different doses of oxymatrine. Additionally, 120 and 90 mg/kg oxymatrine were shown to reduce protein levels of nuclear factor-KB p65 in the nucleus and of phosphorylated IKBa in the cytoplasm of brain cells, as detected by western blot assay. Experimental findings indicate that oxymatrine may inhibit neuroinflammation in rat brain via downregulating the expression of molecules in the toll-like receptor 4/nuclear factor-KB signaling Dathwav.

Pathogenesis of RON receptor tyrosine kinase in cancer cells: activation mechanism, functional crosstalk, and signaling addiction

The RON receptor tyrosine kinase, a member of the MET proto-oncogene family, is a pathogenic factor im- plicated in tumor malignancy. Specifically, aberrations in RON signaling result in increased cancer cell growth, survival, invasion, angiogenesis, and drug resistance. Biochemical events such as ligand binding, receptor over- expression, generation of structure-defected variants, and point mutations in the kinase domain contribute to RON signaling activation. Recently, functional crosstalk between RON and signaling proteins such as MET and EFGR has emerged as an additional mechanism for RON activation, which is critical for tumorigenic develop- ment. The RON signaling crosstalk acts either as a regulatory feedback loop that strengthens or enhances tumor- igenic phenotype of cancer cells or serves as a signaling compensatory pathway providing a growth/survival ad- vantage for cancer cells to escape targeted therapy. Moreover, viral oncoproteins derived from Friend leukemia or Epstein-Barr viruses interact with RON to drive viral oncogenesis. In cancer cells, RON signaling is integrated into cellular signaling network essential for cancer cell growth and survival. These activities provide the mo- lecular basis of targeting RON for cancer treatment. In this review, we will discuss recent data that uncover the mechanisms of RON activation in cancer cells, review evidence of RON signaling crosstalk relevant to cancer malignancy, and emphasize the significance of the RON signaling addiction by cancer cells for tumor therapy. Understanding aberrant RON signaling will not only provide insight into the mechanisms of tumor pathogenesis, but also lead to the development of novel strategies for molecularly targeted cancer treatment.

Research progress on signaling pathways in cirrhotic portal hypertension

Portal hypertension(PHT) is an important consequence of liver cirrhosis, which can lead to complications that adversely affect a patient's quality of life and survival, such as upper gastrointestinal bleeding, ascites, and portosystemic encephalopathy. In recent years, advances in molecular biology have led to major discoveries in the pathological processes of PHT, including the signaling pathways that may be involved: PI3 K-AKT-mTOR, RhoA/Rho-kinase, JAK2/STAT3, and farnesoid X receptor. However, the pathogenesis of PHT is complex and there are numerous pathways involved. Therefore, the targeting of signaling pathways for medical management is lagging. This article summarizes the progress that has been made in understanding the signaling pathways in PHT, and provides ideas for treatment of the disorder.

Hepatitis C virus core protein-induced miR-93-5p upregulation inhibits interferon signaling pathway by targeting IFNAR1

AIM To investigate the mechanism by which hepatitis C virus(HCV) core protein-induced mi R-93-5 p up-regulation regulates the interferon(IFN) signaling pathway.METHODS HCV-1 b core protein was exogenously expressed in Huh7 cells using pc DNA3.1(+) vector. The expression of mi R-93-5 p and interferon receptor 1(IFNAR1) was measured using quantitative reverse transcriptionpolymerase chain reaction and Western blot. The protein expression and phosphorylation level of STAT1 were evaluated by Western blot. The overexpression and silencing of mi R-93-5 p and IFNAR1 were performed using mi R-93-5 p agomir and antagomir, and pc DNA3.1-IFNAR1 and IFNAR1 si RNA, respectively. Luciferase assay was used to identify whether IFNAR1 is a target of mi R-93-5 p. Cellular experiments were also conducted.RESULTS Serum mi R-93-5 p level was increased in patients with HCV-1 b infection and decreased to normal level after HCV-1 b clearance, but persistently increased in those with pegylated interferon-α resistance, compared with healthy subjects. Serum mi R-93-5 p expression had an AUC value of 0.8359 in distinguishing patients with pegylated interferon-α resistance from those with pegylated interferon-α sensitivity. HCV-1 b core protein increased mi R-93-5 p expression and induced inactivation of the IFN signaling pathway in Huh7 cells. Furthermore, IFNAR1 was identified as a direct target of mi R-93-5 p, and IFNAR1 restore could rescue mi R-93-5 p-reduced STAT1 phosphorylation, suggesting that the mi R-93-5 p-IFNAR1 axis regulates the IFN signaling pathway.CONCLUSION HCV-1 b core protein-induced mi R-93-5 p up-regulation inhibits the IFN signaling pathway by directly targeting IFNAR1, and the mi R-93-5 p-IFNAR1 axis regulates STAT1 phosphorylation. This axis may be a potential therapeutic target for HCV-1 b infection.

Wnt-/-β-catenin pathway signaling in human hepatocellular carcinoma

The molecular basis of the carcinogenesis of hepatocellular carcinoma(HCC) has not been adequately clarified, which negatively impacts the development of targeted therapy protocols for this overwhelming neoplasia. The aberrant activation of signaling in the HCC is primarily due to the deregulated expression of the components of the Wnt-/-β-catenin. This leads to the activation of β-catenin/T-cell factor-dependent target genes that control cell proliferation, cell cycle, apoptosis, and cell motility. The deregulation of the Wnt pathway is an early event in hepatocarcinogenesis. An aggressive phenotype was associated with HCC, since this pathway is implicated in the proliferation, migration, and invasiveness of cancer cells, regarding the cell's own survival. The disruption of the signaling cascade Wnt-/-β-catenin has shown anticancer properties in HCC's clinical evaluations of therapeutic molecules targeted for blocking the Wnt signaling pathway for the treatment of HCC, and it represents a promising perspective. The key to bringing this strategy in to clinical practice is to identify new molecules that would be effective only in tumor cells with aberrant signaling β-catenin.

Role of Toll-like receptor 4 and Janus kinase and signal transducer and activator of transcription signal transduction pathway in sepsis-induced brain damage

The Janus kinase and signal transducer and activator of transcription （JAK/STAT） signal transduction pathway is involved in sepsis-induced functional damage to the heart, liver, kidney, and other organs. However, the cellular and molecular mechanisms underlying sepsis-induced brain damage remain elusive. In the present study, we found severe loss of neurons in the hippocampal CA1 region in rats with sepsis-induced brain damage following intraperitoneal injection of endotoxin, The expression of toll-like receptor 4, tumor necrosis factor a, and interleukin-6 was significantly increased in brain tissues following lipopolysaccharide exposure. AG490 （JAK2 antagonist） and rapamycin （STAT3 antagonist） significantly reduced neuronal loss and suppressed the increased expression of toll-like receptor 4, tumor necrosis factor a, and interleukin-6 in the hippocampal CA1 region in sepsis-induced brain damaged rats. Overall, these data suggest that blockade of the JAK/STAT signal transduction pathway is neuroprotective in sepsis-induced brain damage via the inhibition of toll-like receptor 4, tumor necrosis factor a, and interleukin-6 exoression.

Involvement of M3 Cholinergic Receptor Signal Transduction Pathway in Regulation of the Expression of Chemokine MOB-1, MCP-1 Genes in Pancreatic Acinar Cells

Whether M3 cholinergic receptor signal transduction pathway is involved in regulation of the activation of NF-κB and the expression of chemokine MOB-1, MCP-1genes in pancreatic acinar cells was investigated. Rat pancreatic acinar cells were isolated, cultured and treated with carbachol, atropine and PDTC in vitro. The MOB-1 and MCP-1 mRNA expression was detected by using RT-PCR. The activation of NF-κB was monitored by using electrophoretic mobility shift assay. The results showed that as compared with control group, M3 cholinergic receptor agonist (10 -3 mol/L, 10 -4 mol/L carbachol) could induce a concentration-dependent and time-dependent increase in the expression of MOB-1, MCP-1 mRNA in pancreatic acinar cells. After treatment with 10 -3 mol/L carbachol for 2 h, the expression of MOB-1, MCP-1 mRNA was strongest. The activity of NF-κB in pancreatic acinar cells was significantly increased (P<0.01) after treated with M3 cholinergic receptor agonist (10 -3 mol/L carbachol) in vitro for 30 min. Either M3 cholinergic receptor antagonist (10 -5 mol/L atropine) or NF-κB inhibitor (10 -2 mol/L PDTC) could obviously inhibit the activation of NF-κB and the chemokine MOB-1, MCP-1 mRNA expression induced by carbachol (P<0.05). This inhibitory effect was significantly increased by atropine plus PDTC (P<0.01). The results of these studies indicated that M3 cholinergic receptor signal transduction pathway was likely involved in regulation of the expression of chemokine MOB-1 and MCP-1genes in pancreatic acinar cells in vitro through the activation of NF-κB.

Endogenous Endothelin-1 Regulates Hypoxia-Induced Atrial Natriuretic Peptide Secretion by Activating the MAPK/ERK and PI3K/Akt Signaling Pathways in Isolated Beating Rabbit Atria

The present study investigated a possible mechanism for endogenous endothelin-1 (ET-1) regulation of atrial natriuretic peptide (ANP) secretion in isolated perfused acute hypoxic rabbit atria. Acute hypoxia significantly enhanced the release of ET-1 and the expression of the ET receptor (ETR) type A and B (ETRA and ETRB) in atrial tissues, with a concomitant increase in ANP secretion. The ETRA or ETRB antagonist, BQ123 (0.3 μmol/L) or BQ788 (0.3 μmol/L), respectively attenuated hypoxia-induced ANP secretion. Both antagonists significantly attenuated the levels of hypoxiainduced atrial phosphorylated (p)-extracellular signal-regulated kinase (ERK) and p-protein kinase B (Akt). The ERK and Akt inhibitors, PD098059 (30 μmol/L) and LY294002 (30 μmol/L), respectively mimicked the effect of the ETR antagonists. These results demonstrated that acute hypoxia- mediated atrial ET-1 regulated ANP secretion through ETR and the subsequent mitogenactivated protein kinase (MAPK)/ERK and ETR-phosphatidylinositol-3-kinase (PI3K)/Akt signaling pathways. These pathways may mediate atrial endocrine functions under hypoxic conditions.