scholarly journals An Anthranilate Derivative Inhibits Glutamate Release and Glutamate Excitotoxicity in Rats

2022 ◽  
Author(s):  
Cheng-Wei Lu ◽  
Chen-Yung Lin ◽  
Pei-Wen Hsieh ◽  
Kuan-Ming Chiu ◽  
Ming-Yi Lee ◽  
...  
Keyword(s):  
Glutamate Release ◽  
Inhibitory Effect ◽  
Glutamate Excitotoxicity ◽  
Kinase Substrate ◽  
Homologous Protein ◽  
Kinase C ◽  
Level Elevation ◽  
Excitatory Neurotransmission ◽  
Related Proteins

Abstract The neurotransmitter glutamate plays an essential role in excitatory neurotransmission; however, excessive amounts of glutamate lead to excitotoxicity, which is the most common pathogenic feature of numerous brain disorders. This study aimed to investigate the role of butyl 2-[2-(2-fluorophenyl)acetamido]benzoate (HFP034), a synthesized anthranilate derivative, in the central glutamatergic system. We used rat cerebrocortical synaptosomes to examine the effect of HFP034 on glutamate release. In addition, we used a rat model of kainic acid (KA)-induced glutamate excitotoxicity to evaluate the neuroprotective potential of HFP034. We showed that HFP034 inhibits 4-aminopyridine (4-AP)-induced glutamate release from synaptosomes, and this inhibition was absent in the absence of extracellular calcium. HFP034-mediated inhibition of glutamate release was associated with decreased 4-AP-evoked Ca2+ level elevation and had no effect on synaptosomal membrane potential. The inhibitory effect of HFP034 on evoked glutamate release was suppressed by blocking P/Q-type Ca2+ channels and protein kinase C (PKC). Furthermore, HFP034 inhibited the phosphorylation of PKC and its substrate, myristoylated alanine‐rich C kinase substrate (MARCKS), in synaptosomes. We also observed that HFP034 pretreatment reduced neuronal death, glutamate concentration, glial activation, and the levels of endoplasmic reticulum stress-related proteins, calpains, glucose-regulated protein 78 (GRP 78), C/EBP homologous protein (CHOP), and caspase-12 in the hippocampus of KA-injected rats. We conclude that HFP034 is a neuroprotective agent that prevents glutamate excitotoxicity, and we suggest that this effect involves inhibition of presynaptic glutamate release through the suppression of P/Q‐type Ca2+ channels and PKC/MARCKS pathways.

scholarly journals Anthranilate Derivative Inhibits Glutamate Release and Glutamate Excitotoxicity In Rats

2021 ◽  
Author(s):  
Tzu-Yu Lin ◽  
Cheng-Wei Lu ◽  
Pei-Wen Hsieh ◽  
Kuan-Ming Chiu ◽  
Ming-Yi Lee ◽  
...  
Keyword(s):  
Glutamate Release ◽  
Inhibitory Effect ◽  
Glutamate Excitotoxicity ◽  
Kinase Substrate ◽  
Homologous Protein ◽  
Kinase C ◽  
Level Elevation ◽  
Excitatory Neurotransmission ◽  
Related Proteins

Abstract The neurotransmitter glutamate plays an essential role in excitatory neurotransmission; however, excessive glutamate leads to excitotoxicity, which is the most common pathogenic feature of numerous brain disorders. This study aimed to investigate the role of butyl 2-[2-(2-fluorophenyl)acetamido]benzoate (HFP034), a synthesized anthranilate derivative, in the central glutamatergic system. We used rat cerebrocortical synaptosomes to examine the effect of HFP034 on glutamate release. In addition, we used a rat model of kainic acid (KA)-induced glutamate excitotoxicity to evaluate the neuroprotective potential of HFP034. We showed that HFP034 inhibited 4-aminopyridine (4-AP)-induced glutamate release from the synaptosomes, and this inhibition was abolished in the absence of extracellular calcium. HFP034-mediated inhibition of glutamate release was associated with a decreased 4-AP-evoked Ca2+ level elevation, and had no effect on synaptosomal membrane potential. The inhibitory effect of HFP034 on evoked glutamate release was suppressed by blocking P/Q-type Ca2+ channels and protein kinase C (PKC). Furthermore, HFP034 inhibited the phosphorylation of PKC and its substrate, myristoylated alanine-rich C kinase substrate (MARCKS), in the synaptosomes. We also observed that HFP034 pretreatment reduced neuronal death, glutamate concentration, glial activation, and the levels of endoplasmic reticulum stress-related proteins, calpains, glucose-regulated protein 78 (GRP 78), C/EBP homologous protein (CHOP), and caspase-12 in the hippocampus of KA-injected rats. We concluded that HFP034 is a neuroprotective agent that prevents glutamate excitotoxicity, and we suggest that this effect involves the inhibition of presynaptic glutamate release by suppressing P/Q‐type Ca2+ channels and PKC/MARCKS pathways.

scholarly journals Inhibition of IL-13 and IL-13Rα2 Expression by IL-32θ in Human Monocytic Cells Requires PKCδ and STAT3 Association

2019 ◽  
Vol 20 (8) ◽  
pp. 1949 ◽  
Author(s):  
Thu-Huyen Pham ◽  
Yesol Bak ◽  
Jae-Wook Oh ◽  
Jingi Hong ◽  
Seungyeoun Lee ◽  
...  
Keyword(s):  
Mrna Expression ◽  
Nuclear Translocation ◽  
Inhibitory Effect ◽  
Additive Effects ◽  
Signal Transducer ◽  
Monocytic Cells ◽  
Kinase C ◽  
Direct Association ◽  
Transcription 3

Interleukin (IL)-32θ, a newly identified IL-32 isoform, has been reported to exert pro-inflammatory effects through the association with protein kinase C delta (PKCδ). In this study, we further examined the effects of IL-32θ on IL-13 and IL-13Rα2 expression and the related mechanism in THP-1 cells. Upon stimulating IL-32θ-expressing and non-expressing cells with phorbol 12-myristate 13-acetate (PMA), the previous microarray analysis showed that IL-13Rα2 and IL-13 mRNA expression were significantly decreased by IL-32θ. The protein expression of these factors was also confirmed to be down-regulated. The nuclear translocation of transcription factors STAT3 and STAT6, which are necessary for IL-13Rα2 and IL-13 promoter activities, was suppressed by IL-32θ. Additionally, a direct association was found between IL-32θ, PKCδ, and signal transducer and activator of transcription 3 (STAT3), but not STAT6, revealing that IL-32θ might act mainly through STAT3 and indirectly affect STAT6. Moreover, the interaction of IL-32θ with STAT3 requires PKCδ, since blocking PKCδ activity eliminated the interaction and consequently limited the inhibitory effect of IL-32θ on STAT3 activity. Interfering with STAT3 or STAT6 binding by decoy oligodeoxynucleotides (ODNs) identified that IL-32θ had additive effects with the STAT3 decoy ODN to suppress IL-13 and IL-13Rα2 mRNA expression. Taken together, our data demonstrate the intracellular interaction of IL-32θ, PKCδ, and STAT3 to regulate IL-13 and IL-13Rα2 synthesis, supporting the role of IL-32θ as an inflammatory modulator.

Regulation of eosinophil function by phosphatidylinositol-specific PLC and cytosolic PLA2

2001 ◽  
Vol 281 (4) ◽  
pp. L844-L851 ◽  
Author(s):  
Akiko Sano ◽  
Xiangdong Zhu ◽  
Hiroyuki Sano ◽  
Nilda M. Muñoz ◽  
Evan Boetticher ◽  
...  
Keyword(s):  
Inhibitory Effect ◽  
Acetoxymethyl Ester ◽  
Protein Kinase C Inhibitors ◽  
Cytosolic Phospholipase ◽  
Kinase C ◽  
Intracellular Ca ◽  
Cytosolic Pla2 ◽  
Arachidonate Release ◽  
Eosinophil Degranulation

We examined the regulatory role of cytosolic phospholipase A2 (cPLA2) and phosphatidylinositol (PI)-specific phospholipase C (PLC) in the degranulation of human eosinophils and leukotriene (LT) C4synthesis. Activation with formyl-Met-Leu-Phe + cytochalasin B (fMLP/B) caused a time-dependent release of eosinophil peroxidase (EPO) and LTC4, which was inhibited by pertussis toxin. By immunoblotting, eosinophil PLC-β2 and -γ2 isoforms were identified, and PLC activation was measured as a function of inositol 1,4,5-trisphosphate concentration. Stimulated release of EPO and intracellular Ca2+ concentration was inhibited by ET-18-OCH3, a PI-PLC inhibitor, whereas trifluoromethylketone (TFMK), a cPLA2blocker, had no inhibitory effect. Both TFMK and ET-18-OCH3attenuated stimulated arachidonate release and LTC4secretion, suggesting that activation of both PLC and cPLA2is essential for LTC4 synthesis caused by fMLP/B. The structurally unrelated protein kinase C inhibitors bisindolylmaleimide, Ro-31–8220, and Go-6976 all blocked fMLP/B-induced EPO release but not LTC4 secretion. 1,2-bis(2-Aminophenoxy)ethane- N,N,N′,N′- tetraacetic acid acetoxymethyl ester, an intracellular Ca2+ chelator, suppressed both EPO release and LTC4 secretion. We found that fMLP/B-induced LTC4 secretion from human eosinophils is regulated by PI-PLC through calcium-mediated activation of cPLA2. However, cPLA2 does not regulate eosinophil degranulation.

Localization of IP in rabbit kidney and functional role of the PGI2/IP system in cortical collecting duct

2002 ◽  
Vol 283 (4) ◽  
pp. F689-F698 ◽  
Author(s):  
Rania Nasrallah ◽  
Rolf M. Nusing ◽  
Richard L. Hébert
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Functional Role ◽  
Collecting Duct ◽  
Inhibitory Effect ◽  
Rabbit Kidney ◽  
Cortical Collecting Duct ◽  
Kinase C ◽  
Protein Kinase C Inhibitor

To clarify the role of the PGI2/PGI2 receptor (IP) system in rabbit cortical collecting duct (RCCD), we characterized the expression of IP receptors in the rabbit kidney. We show by Northern and Western blotting that IP mRNA and protein was detectable in all three regions of the kidney. To determine how PGI2 signals, we compared the effects of different PGI2 analogs [iloprost (ILP), carba-prostacyclin (c-PGI2), and cicaprost (CCP)] in the isolated perfused RCCD. PGI2 analogs did not increase water flow ( L p). Although PGI2 analogs did not reduce an established L p response to 8-chlorophenylthio-cAMP, they equipotently inhibited AVP-stimulated L p by 45%. The inhibitory effect of ILP and c-PGI2 on AVP-stimulated L p is partially reversed by the protein kinase C inhibitor staurosporine and abolished by pertussis toxin; no effect was obtained with CCP. In fura 2-loaded RCCD, CCP did not alter cytosolic Ca2+concentration ([Ca2+]i), but, in the presence of CCP, individual infusion of ILP and PGE2 increased [Ca2+]i, suggesting that CCP did not cause desensitization to either ILP or PGE2. We concluded that ILP and c-PGI2 activate PKC and the liberation of [Ca2+]i but not CCP. This suggested an important role for phosphatidylinositol hydrolysis in mediating ILP and c-PGI2 effects but not CCP in RCCD.

scholarly journals Glutamine protects against apoptosis via downregulation of Sp3 in intestinal epithelial cells

2010 ◽  
Vol 299 (6) ◽  
pp. G1344-G1353 ◽  
Author(s):  
Kechen Ban ◽  
Rosemary A. Kozar
Keyword(s):  
Protein Expression ◽  
Inhibitory Effect ◽  
Protective Effects ◽  
Intestinal Epithelial ◽  
Bax Protein ◽  
Gut Function ◽  
Dose Dependent Fashion ◽  
Specificity Protein ◽  
Related Proteins

Glutamine plays a key role in intestinal growth and maintenance of gut function, and as we have shown protects the postischemic gut (Kozar RA, Scultz SG, Bick RJ, Poindexter BJ, Desoigne R, Weisbrodt NW, Haber MM, Moore FA. Shock 21: 433–437, 2004). However, the precise mechanisms of the gut protective effects of glutamine have not been well elucidated. In the present study, RNA microarray was performed to obtain differentially expressed genes in intestinal epithelial IEC-6 cells following either 2 mM or 10 mM glutamine. The result demonstrated that specificity protein 3 (Sp3) mRNA expression was downregulated 3.1-fold. PCR and Western blot confirmed that Sp3 expression was decreased by glutamine in a time- and dose-dependent fashion. To investigate the role of Sp3, Sp3 gene siRNA silencing was performed and apoptosis was assessed. Silencing of Sp3 demonstrated a significant increase in Bcl-2 and decrease in Bax protein expression, as well as a decrease in caspase-3, -8, and -9 protein expression and activity. The protein expression of apoptosis-related proteins after hypoxia/reoxygenation was similar to that of normoxia and correlated with a decrease in DNA fragmentation. Importantly, the addition of glutamine to Sp3-silenced cells did not further lessen apoptosis, suggesting that Sp3 plays a major role in the inhibitory effect of glutamine on apoptosis. This novel finding may explain in part the gut-protective effects of glutamine.

Alcohol preference in mice lacking the Avpr1a vasopressin receptor

2008 ◽  
Vol 294 (5) ◽  
pp. R1482-R1490 ◽  
Author(s):  
Atsushi Sanbe ◽  
Norio Takagi ◽  
Yoko Fujiwara ◽  
Junji Yamauchi ◽  
Toshiya Endo ◽  
...  
Keyword(s):  
Glutamate Release ◽  
Ethanol Consumption ◽  
Inhibitory Effect ◽  
Presynaptic Terminal ◽  
Behavioral Effects ◽  
Wild Type ◽  
Pressure Water ◽  
The Central Nervous System ◽  
Voluntary Ethanol Consumption

[Arg8]-vasopressin (Avp), a nonapeptide hormone, is known to regulate blood pressure, water balance, and a variety of behaviors such as anxiety, aggression, and bonding. Although some evidence that Avp modifies ethanol consumption and some of the effects of ethanol on behavior have been reported, the role of Avp in alcohol consumption and preference is poorly understood. The Avp1a receptor (Avpr1a) is ubiquitously expressed in the central nervous system. To determine the role of Avp signaling on the behavioral effects of alcohol, we examined voluntary ethanol consumption in mice with targeted disruptions of the Avpr1a knockout (Avpr1a KO) gene. Avpr1a KO mice displayed both increased ethanol consumption and preference compared with wild-type (WT) mice. Enhanced ethanol consumption was dramatically and reversibly reduced by treatment with N-methyl-d-aspartic acid antagonists. Basal glutamate release was elevated around the striatum in Avpr1a KO mice. Elevation of extracellular glutamate was also produced in WT mice by local application of an Avpr1a antagonist though a dialysis probe, and this elevation was quickly reversed by stopping the perfusion. These results suggest that Avp can inhibit the release of glutamate from the presynaptic terminal via the Avp1a receptor and that elevation of glutamate levels owing to loss of the inhibitory effect via Avp-Avpr1a signaling may play an important role in the preference for ethanol.

scholarly journals Evaluation of GABAergic Transmission Modulation as a Novel Functional Target for Management of Multiple Sclerosis: Exploring Inhibitory Effect of GABA on Glutamate-Mediated Excitotoxicity

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Ankit A. Gilani ◽  
Ranjeet Prasad Dash ◽  
Mehul N. Jivrajani ◽  
Sandeep Kumar Thakur ◽  
Manish Nivsarkar
Keyword(s):  
Multiple Sclerosis ◽  
Sodium Valproate ◽  
Glutamate Release ◽  
Inhibitory Effect ◽  
Glutamate Excitotoxicity ◽  
Nerve Terminals ◽  
Moderate Activity ◽  
Gamma Aminobutyric Acid ◽  
Metabotropic Receptors ◽  
Potential Implication

Multiple sclerosis (MS) is an autoimmune inflammatory disease of the central nervous system (CNS) where the communication ability of nerve cells in the brain and spinal cord with each other gets impaired. Some current findings suggest the role of glutamate excitotoxicity in the development and progression of MS. An excess release of glutamate leads to the activation of ionotropic and metabotropic receptors, thus resulting in accumulation of toxic cytoplasmic Ca2+and cell death. However, it has been observed that gamma-aminobutyric acid-A (GABAA) receptors located in the nerve terminals activate presynaptic Ca2+/calmodulin-dependent signaling to inhibit depolarization-evoked Ca2+influx and glutamate release from isolated nerve terminals, which suggest a potential implication of GABAAreceptor in management of MS. With this proof of concept, we tried to explore the potential of selective GABAAreceptor agonists or positive allosteric modulators (diazepam and phenobarbitone sodium) and GABAAlevel enhancer (sodium valproate) for management of MS by screening them for their activity in experimental autoimmune encephalomyelitis (EAE) model in rats and cuprizone-induced demyelination model in mice. In this study, sodium valproate was found to show the best activity in the animal models whereas phenobarbitone sodium showed moderate activity. However, diazepam was found to be ineffective.

scholarly journals Lycopene depresses glutamate release through inhibition of voltage-dependent Ca2+ entry and protein kinase C in rat cerebrocortical nerve terminals

2018 ◽  
Vol 96 (5) ◽  
pp. 479-484 ◽  
Author(s):  
Cheng-Wei Lu ◽  
Chi-Feng Hung ◽  
Wei-Horng Jean ◽  
Tzu-Yu Lin ◽  
Shu-Kuei Huang ◽  
...  
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Glutamate Release ◽  
Inhibitory Effect ◽  
Nerve Terminals ◽  
Protein Kinase C Inhibitors ◽  
Kinase C ◽  
Protein Kinase C Activity ◽  
Voltage Dependent ◽  
Intracellular Ca

Lycopene is a natural dietary carotenoid that was reported to exhibit a neuroprotective profile. Considering that excitotoxicity and cell death induced by glutamate are involved in many brain disorders, the effect of lycopene on glutamate release in rat cerebrocortical nerve terminals and the possible mechanism involved in such effect was investigated. We observed here that lycopene inhibited 4-aminopyridine (4-AP)-evoked glutamate release and intrasynaptosomal Ca2+ concentration elevation. The inhibitory effect of lycopene on 4-AP-evoked glutamate release was markedly reduced in the presence of the Cav2.2 (N-type) and Cav2.1 (P/Q-type) channel blocker ω-conotoxin MVIIC, but was insensitive to the intracellular Ca2+-release inhibitors dantrolene and CGP37157. Furthermore, in the presence of the protein kinase C inhibitors GF109203X and Go6976, the action of lycopene on evoked glutamate release was prevented. These results are the first to suggest that lycopene inhibits glutamate release from rat cortical synaptosomes by suppressing presynaptic Ca2+ entry and protein kinase C activity.

scholarly journals Varicella-Zoster Virus gB and gE Coexpression, but Not gB or gE Alone, Leads to Abundant Fusion and Syncytium Formation Equivalent to Those from gH and gL Coexpression

2001 ◽  
Vol 75 (19) ◽  
pp. 9483-9492 ◽  
Author(s):  
Lucie Maresova ◽  
Tracy Jo Pasieka ◽  
Charles Grose
Keyword(s):  
Varicella Zoster Virus ◽  
Expression System ◽  
Syncytium Formation ◽  
Inhibitory Effect ◽  
Varicella Zoster ◽  
Homologous Protein ◽  
Simplex Virus ◽  
Expression Plasmids

ABSTRACT Varicella-zoster virus (VZV) is distinguished from herpes simplex virus type 1 (HSV-1) by the fact that cell-to-cell fusion and syncytium formation require only gH and gL within a transient-expression system. In the HSV system, four glycoproteins, namely, gH, gL, gB, and gD, are required to induce a similar fusogenic event. VZV lacks a gD homologous protein. In this report, the role of VZV gB as a fusogen was investigated and compared to the gH-gL complex. First of all, the VZV gH-gL experiment was repeated under a different set of conditions; namely, gH and gL were cloned into the same vaccinia virus (VV) genome. Surprisingly, the new expression system demonstrated that a recombinant VV-gH+gL construct was even more fusogenic than seen in the prior experiment with two individual expression plasmids containing gH and gL (K. M. Duus and C. Grose, J. Virol. 70:8961–8971, 1996). Recombinant VV expressing VZV gB by itself, however, effected the formation of only small syncytia. When VZV gE and gB genes were cloned into one recombinant VV genome and another fusion assay was performed, extensive syncytium formation was observed. The degree of fusion with VZV gE-gB coexpression was comparable to that observed with VZV gH-gL: in both cases, >80% of the cells in a monolayer were fused. Thus, these studies established that VZV gE-gB coexpression greatly enhanced the fusogenic properties of gB. Control experiments documented that the fusion assay required a balance between the fusogenic potential of the VZV glycoproteins and the fusion-inhibitory effect of the VV infection itself.

Role of iduronate-2-sulfatase in glucose-stimulated insulin secretion by activation of exocytosis

2009 ◽  
Vol 297 (3) ◽  
pp. E793-E801 ◽  
Author(s):  
S. Piquer ◽  
S. Casas ◽  
I. Quesada ◽  
A. Nadal ◽  
M. Julià ◽  
...  
Keyword(s):  
Insulin Secretion ◽  
Dermatan Sulfate ◽  
Mrna Levels ◽  
Transfected Cells ◽  
Kinase Substrate ◽  
Kinase C ◽  
Insulin Mrna ◽  
Glucose Stimulated Insulin Secretion ◽  
Insulin Secretory Response

Iduronate-2-sulfatase (IDS) is a lysosomal enzyme expressed in pancreatic islets responsible for the degradation of proteoglycans such as perlecan and dermatan sulfate. Previous findings of our group demonstrated the involvement of IDS in the normal pathway of lysosomal degradation of secretory peptides, suggesting a role of this enzyme in β-cell secretory functionality. The present study was undertaken to characterize the effect of IDS overexpression on insulin release. INS1E cells were transiently transfected with a construct encoding human IDS (hIDS). hIDS overexpression was associated with a gain of function detected by a reduction in heparan sulfate content. hIDS potentiated the glucose-stimulated insulin secretory response compared with controls (61%) with no changes in insulin mRNA levels or insulin peptide content. Results on quantification of the exocytotic process showed a significant increase in hIDS-transfected cells compared with controls. Furthermore, ultramorphological analysis demonstrated an increase in the number of granules in the immediate vicinity of the plasma membrane in hIDS-transfected cells and a decrease in total vesicles per square micrometer. hIDS overexpression induced phosphorylation of protein kinase C (PKC) α and its newly myristoylated alanine-rich C kinase substrate, MARCKS. We conclude that IDS has a role in glucose-stimulated insulin secretion via a mechanism that involves the activation of exocytosis through phosphorylation of PKCα and MARCKS.

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