• Biomolecules & Therapeutics
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• 제26권2호
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• pp.201-209
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• 2018

G protein-coupled receptor 119 (GPR119) is expressed in the pancreas and gastrointestinal tract, and its activation promotes insulin secretion in the beta cells of the pancreatic islets as well as the secretion of glucagon-like peptide-1 (GLP-1) in intestinal L cells, consequently improving glucose-stimulated insulin secretion. Due to this dual mechanism of action, the development of small-molecule GPR119 agonists has received significant interest for the treatment of type 2 diabetes. We newly synthesized 1,2,4-triazolone derivatives of GPR119 agonists, which demonstrated excellent outcomes in a cyclic adenosine monophosphate (cAMP) assay. Among the synthesized derivatives, YH18968 showed cAMP=2.8 nM; in GLUTag cell, GLP-1secretion=2.3 fold; in the HIT-T15 cell, and insulin secretion=1.9 fold. Single oral administration of YH18968 improved glucose tolerance and combined treatment with a dipeptidyl peptidase 4 (DPP-4) inhibitor augmented the glucose lowering effect as well as the plasma level of active GLP-1 in normal mice. Single oral administration of YH18968 improved glucose tolerance in a diet induced obese mice model. This effect was maintained after repeated dosing for 4 weeks. The results indicate that YH18968 combined with a DPP-4 inhibitor may be an effective therapeutic candidate for the treatment of type 2 diabetes.

• Natural Product Sciences
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• 제22권4호
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• pp.246-251
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• 2016

This study investigated the effects of (-)-sesamin on memory deficits in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-lesioned mouse model of Parkinson's disease (PD). MPTP lesion (30 mg/kg/day, 5 days) in mice showed memory deficits including habit learning memory and spatial memory. However, treatment with (-)-sesamin (25 and 50 mg/kg) for 21 days ameliorated memory deficits in MPTP-lesioned mouse model of PD: (-)-sesamin at both doses improved decreases in the retention latency time of the passive avoidance test and the levels of dopamine, norepinephrine, 3,4-dihydroxyphenylacetic acid, and homovanillic acid, improved the decreased transfer latency time of the elevated plus-maze test, reduced the increased expression of N-methyl-D-aspartate (NMDA) receptor, and increased the reduced phosphorylation of extracellular signal-regulated kinase (ERK1/2) and cyclic AMP-response element binding protein (CREB). These results suggest that (-)-sesamin has protective effects on both habit learning memory and spatial memory deficits via the dopaminergic neurons and NMDA receptor-ERK1/2-CREB system in MPTP-lesioned mouse model of PD, respectively. Therefore, (-)-sesamin may serve as an adjuvant phytonutrient for memory deficits in PD patients.

• Journal of Microbiology and Biotechnology
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• 제10권5호
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• pp.670-676
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• 2000

Several clones obtained from Serratia marcescens stimulated E. coli TP2139 (${\Delta}lac, \;{\Delta} crp$) cells to use maltose as a carbon source. The crp gene clone, pCKB12, was confirmed to stimulate the $\beta$-galactosidase activity, by Southern hybridization [31]. The nucleotide sequence of the crp region consisting of 1,979 bp was determined. The sequencing of the fragment led to the identification of two open reading frames: One of these, the crp gene, encoded 210 amino acid and the other encoded a truncated protein. The S. marcescens and E. coli crp genes showed a higher degree of divergence in their nucleotide sequence with 120 changes, however, the corresponding amino acid sequences showed only two amino acid differences. Yet, an analysis of the amino acid divergence revealed that the catabolite gene activator protein, the crp gene product, was the most conserved protein observed so far. Using a crp-lac protein fusion, it was demonstrated that S. marcescens CRP could repress its own expression, probably via a mechanism similar to that previously described for the E. coli crp gene.

• IMMUNE NETWORK
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• 제3권3호
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• pp.201-210
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• 2003

Objective: The role of prostaglandin $E_2$ (PGE2) in the etiopathogenesis of immune and inflammatory diseases has become the subject of recent debate. To determine the role of PGE2 in rheumatoid arthritis (RA), we tested the effect of exogenous PGE2 on the production of cyclooxygenase-2 (COX-2) by rheumatoid synoviocytes. Methods: Fibroblast-like synoviocytes (FLS) were prepared from the synovial tissues of RA patients, and cultured in the presence of PGE2. The COX-2 mRNA and protein expression levels were determined by RT-PCR and Western blot analysis, respectively. The PGE2 receptor subtypes in the FLS were analyzed by RT-PCR. Electrophoretic mobility shift assay (EMSA) was used to measure the NF-${\kappa}B$ binding activity for COX-2 transcription. The in vivoeffect of PGE2 on the development of arthritis was also tested in collagen induced arthritis (CIA) animals. Results: PGE2 ($10^{-11}$ to $10^{-5}M$) dose-dependently inhibited the expression of COX-2 mRNA and the COX-2 protein stimulated with IL-$1{\beta}$, but not COX-1 mRNA. NS-398, a selective COX-2 inhibitor, displayed an additive effect on PGE2-induced COX-2 downregulation. The FLS predominantly expressed the PGE2 receptor (EP) 2 and EP4, which mediated the COX-2 suppression by PGE2. Treatment with anti-IL-10 monoclonal antibodies partially reversed the PGE2-induced suppression of COX-2 mRNA, suggesting that IL-10 may be involved in modulating COX-2 by PGE2. Experiments using an inducer and an inhibitor of cyclic AMP (cAMP) suggest that cAMP is the major intracellular signal that mediates the regulatory effect of PGE2 on COX-2 expression. EMSA revealed that PGE2 inhibited the binding of NF-${\kappa}B$ in the COX-2 promoter via a cAMP dependent pathway. In addition, a subcutaneous injection of PGE2 twice daily for 2 weeks significantly reduced the incidence and severity of CIA as well as the production of IgG antibodies to type II collagen. Conclusion: Our data suggest that overproduced PGE2 in the RA joints may function as an autocrine regulator of its own synthesis by inhibiting COX-2 production and may, in part, play an anti-inflammatory role in the arthritic joints.

• 대한의생명과학회지
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• 제23권3호
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• pp.251-260
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• 2017

Platelet activation is essential at the sites of vascular injury, which leads to hemostasis through adhesion, aggregation, and secretion process. However, potent and continuous platelet activation may be an important reason of circulatory disorders. Therefore, proper regulation of platelet activation may be an effective treatment for vascular diseases. In this research, inhibitory effects of cordycepin (3'-deoxyadenosine) on platelet activation were determined. As the results, cordycepin increased cAMP and cGMP, which are intracellular $Ca^{2+}$-antagonists. In addition, cordycepin reduced collagen-elevated $[Ca^{2+}]_i$ mobilization, which was increased by a cAMP-dependent protein kinase (PKA) inhibitor (Rp-8-Br-cAMPS), but not a cGMP-protein kinase (PKG) inhibitor (Rp-8-Br-cGMPS). Furthermore, cordycepin increased $IP_3RI$ ($Ser^{1756}$) phosphorylation, indicating inhibition of $IP_3$-mediated $Ca^{2+}$ release from internal store via the $IP_3RI$, which was strongly inhibited by Rp-8-Br-cAMPS, but was not so much inhibited by Rp-8-Br-cGMPS. These results suggest that the reduction of $[Ca^{2+}]_i$ mobilization is caused by the cAMP/A-kinase-dependent $IP_3RI$ ($Ser^{1756}$) phosphorylation. In addition, cordycepin increased the phosphorylation of VASP ($Ser^{157}$) known as PKA substrate, but not VASP ($Ser^{239}$) known as PKG substrate. Cordycepin-induced VASP ($Ser^{157}$) phosphorylation was inhibited by Rp-8-Br-cAMPS, but was not inhibited by Rp-8-Br-cGMPS, and cordycepin inhibited collagen-induced fibrinogen binding to ${\alpha}IIb/{\beta}_3$, which was increased by Rp-8-Br-cAMPS, but was not inhibited by Rp-8-Br-cGMPS. These results suggest that the inhibition of ${\alpha}IIb/{\beta}_3$ activation is caused by the cAMP/A-kinase-dependent VASP ($Ser^{157}$) phosphorylation. In conclusion, these results demonstrate that inhibitory effects of cordycepin on platelet activation were due to inhibition of $[Ca^{2+}]_i$ mobilization through cAMP-dependent $IP_3RI$ ($Ser^{1756}$) phosphorylation and suppression of ${\alpha}IIb/{\beta}_3$ activation through cAMP-dependent VASP ($Ser^{157}$) phosphorylation. These results strongly indicated that cordycepin might have therapeutic or preventive potential for platelet activation-mediated disorders including thrombosis, atherosclerosis, myocardial infarction, or cardiovascular disease.

• 한방비만학회지
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• 제20권2호
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• pp.109-121
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• 2020

Objectives: Tanshinone I is a bioactive constituent in Salvia miltiorrhiza. At present, the anti-obesity effect and mechanism of tanshinone I are not fully understood. Here we investigated the effect of tanshinone I on lipid accumulation in 3T3-L1 preadipocytes and zebrafish. Methods: Lipid accumulation and triglyceride (TG) content in 3T3-L1 cells were determined by Oil Red O staining and AdipoRed assay, respectively. The expression and phosphorylation levels of adipogenic/lipogenic proteins in 3T3-L1 cells were evaluated by Western blotting. The messenger RNA (mRNA) expression levels of adipogenic/lipogenic markers and leptin in 3T3-L1 cells were measured by reverse transcription polymerase chain reaction (RT-PCR). Lipid accumulation in zebrafish was assessed by LipidGreen2 staining. Results: Tanshinone I at 5 μM largely blocked lipid accumulation and reduced TG content in differentiating 3T3-L1 cells. Furthermore, tanshinone I decreased the expression of CCAAT/enhancer-binding protein-α (C/EBP-α), peroxisome proliferator-activated receptor-γ (PPAR-γ), fatty acid synthase (FAS), acetyl CoA carboxylase (ACC), and perilipin A but also the phosphorylation of signal transducer and activator of transcription-3 (STAT-3) in differentiating 3T3-L1 cells. In addition, tanshinone I increased the phosphorylation of adenosine 3',5'-cyclic monophosphate (cAMP)-activated protein kinase (AMPK) while decreased the intracellular adenosine triphosphate (ATP) content with no change in the phosphorylation and expression of liver kinase-B1 in differentiating 3T3-L1 cells. Importantly, tanshinone I also reduced the extent of lipid deposit formation in developing zebrafish. Conclusions: These findings demonstrate that tanshinone I has strong anti-adipogenic effects on 3T3-L1 cells and reduces adiposity in zebrafish, and these anti-adipogenic effect in 3T3-L1 cells are mediated through control of C/EBP-α, PPAR-γ, STAT-3, FAS, ACC, perilipin A, and AMPK.

• Molecules and Cells
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• 제45권5호
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• pp.306-316
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• 2022

Chronic stress contributes to the risk of developing depression; the habenula, a nucleus in epithalamus, is associated with many neuropsychiatric disorders. Using genome-wide gene expression analysis, we analyzed the transcriptome of the habenula in rats exposed to chronic restraint stress for 14 days. We identified 379 differentially expressed genes (DEGs) that were affected by chronic stress. These genes were enriched in neuroactive ligand-receptor interaction, the cAMP (cyclic adenosine monophosphate) signaling pathway, circadian entrainment, and synaptic signaling from the Kyoto Encyclopedia of Genes and Genomes pathway analysis and responded to corticosteroids, positive regulation of lipid transport, anterograde trans-synaptic signaling, and chemical synapse transmission from the Gene Ontology analysis. Based on protein-protein interaction network analysis of the DEGs, we identified neuroactive ligand-receptor interactions, circadian entrainment, and cholinergic synapse-related subclusters. Additionally, cell type and habenular regional expression of DEGs, evaluated using a recently published single-cell RNA sequencing study (GSE137478), strongly suggest that DEGs related to neuroactive ligand-receptor interaction and trans-synaptic signaling are highly enriched in medial habenular neurons. Taken together, our findings provide a valuable set of molecular targets that may play important roles in mediating the habenular response to stress and the onset of chronic stress-induced depressive behaviors.

• 한국미생물·생명공학회지
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• 제38권4호
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• pp.349-361
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• 2010

본 총설에서는 아미노산의 공업적 생산균인 Corynebacterium glutamicum의 탄소 대사 및 이와 관련된 총체적 조절 메커니즘에 대한 최근의 연구를 정리하였다. C. glutamicum의 산업적 발효을 위한 기질로서 사용되는 당밀은 주로 sucrose, glucose, fructose로 이루어져 있으며, 이들 당은 phosphotransferase system을 통해서 수송된다. C. glutamicum의 탄소 대사 특징은 glucose가 다른 당이나 유기산 등과 함께 존재할 때, glucose와 이러한 탄소원 들을 동시에 대사한다. 그러나 glucose/glutamate 혹은 glucose/ethanol 등의 혼합물에서 는 탄소원의 순차적 이용으로 인해 나타나는 diauxic growth 현상을 나타내며, 이러한 carbon catabolite repression(CCR) 현상은 E. coli나 B. subtilis 등에서 알려진 것과는 다른 독특한 분자적 메커니즘과 조절 circuits을 가지고 있음이 밝혀지고 있다. C. glutamicum의 CRP homologue인 GlxR은 acetate 대사를 포함하여 glycolysis, gluconeogenesis 및 TCA cycle 등을 포함하는 중심탄소대사 조절 뿐만 아니라, 다양한 세포 기능의 조절에 관여하는 총체적 조절 단백질로서의 역할이 제시되고 있다. C. glutamicum의 adenylate cyclase(AC)는 막과 결합된 class IIIAC 로서, 막 단백질의 특성상 아직 규명되어 있지 않은 세포 외부의 환경 변화에 대응하여 세포 내의 cAMP합성 수준을 조절할 수 있는 sensor로 추정할 수 있다. 특히 C. glutamicum의 경우 배지내 glucose 를 비롯한 탄소원과 cAMP 농도와의 관련성이 E. coli에서 알려진 교과서적 지식과는 상반되게 변화하는 경향을 보이고 있어, cAMP signaling에 의한 세포 내 regulatory network 등은 향후 풀어야 할 의문으로 남아있다. 탄소대사 조절의 최상위에 존재하며 global 조절자인 GlxRcAMP 복합체 이외에도 차상위 전사조절 단백질로서 RamB, RamA, SugR 등이 존재하여 다양한 탄소대사를 조절한다. 최근 들어서는 새로운 탄소원으로서 대두되고 있는 biomass 관련 기질들을 이용할 수 있는 C. glutamucum 균주 구축을 통하여 이용 기질의 범위를 확대시키고자 하는 연구 및 탄소 대사와 관련하여 L-lysine의 발효 수율 혹은 생산성을 향상시키고자 하는 다양한 분자적 균주 육종 연구 등이 수행되고 있다.

• The Korean Journal of Physiology and Pharmacology
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• 제1권4호
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• pp.413-423
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• 1997

The importance of the kidney in the development of hypertension was first demonstrated by Goldblatt and his colleagues more than fifty years ago. Many hormones and other regulatory factors have been proposed to play a major role in the development of hypertension. Among these factors angiotensia II (ANG II) is closely involved in renal hypertension development since it directly regulates $Na^+$ reabsorption in the renal proximal tubule. Thus the aim of the present study was to examine signaling pathways of low dose of ANC II on the $Na^+$ uptake of primary cultured rabbit renal proximal tubule cells (PTCs) in hormonally defined seum-free medium. The results were as follows: 1) $10^{-11}$ M ANG II has a significant stimulatory effect on growth as compared with control. Alkaline phosphatase exhibited significantly increased activity. However, leucine aminopeptidase and ${\gamma}-glutamyl$ transpeptidase activity were not significant as compared with control. In contrast to $10^{-11}$ M ANG II stimulated $Na^+$ uptake $(108.03{\pm}2.16% of that of control)$, $10^{-9}$ M ANG II inhibited ($92.42{\mu}2.23%$ of that of control). The stimulatory effect of ANG II on $Na^+$ uptake was amiloride-sensitive and inhibited by losartan (ANG II receptor subtype 1 antagonist) and not by PD123319 (ANG II receptor subtype 2 antagonist). 2) Pertussis toxin (PTX) alone inhibited $Na^+$ uptake by $85.52{\pm}3.52%$ of that of control. In addition, PTX pretreatment prevented the AMG II-induced stimulation of $Na^+$ uptake. 8-Bromoadenosine 3',5'-cyclic monophosphate (8-Br-cAMP), forskolin, and isobutylmethylxanthine (IBMX) alone inhibited $Na^+$ uptake by $88.79{\pm}2.56,\;80.63{\pm}4.38,\;and\;84.47{\pm}4.74%$ of that of control, respectively, and prevented the ANG II-induced stimulation of $Na^+$ uptake. However, $10^{-11}$ M ANG II did not stimulate cAMP production. 3) The addition of 12-O-te-tradecanoylphorbol-13-acetate (TPA, 0.01 ng/ml) to the PTCs produced significant increase in $Na^+$ uptake ($114.43{\pm}4.05%$ of that of control). When ANG II and TPA were added together to the PTCs, there was no additive effect on $Na^+$ uptake. Staurosporine alone had no effect on $Na^+$ uptake, but led to a complete inhibition of ANG II- or TPA-induced stimulation of Na'uptake. ANG II treatment resulted in a $111.83{\mu}4.51%$ increase in total protein kinase C (PKC) activity. In conclusion, the PTX-sensitive PKC pathway is the main signaling cascade involved in the stimulatory effects of ANG II on $Na^+$ uptake in the PTCs.

• 동의생리학회지
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• 제14권2호통권20호
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• pp.67-82
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• 1999

The effects of Bogi, Boyang and Onri herbs on glutamte receptor, and the regulatory mechanism of cAMP-protein kinase on the ion currents activated by Bogi, Boyang and Onri herbs using nystatin-perforated patch clamp were investigated and the following results were obtained. Ginseng radix and Astragali radix, Cervi cornu and Boshniakiae herba, and Aconiti tuber and Zingiberis rhizoma were chosen as Bogi, Boyang and Onri herbs respectively. 1. The ion currents activated by $10^{-5}M$ of glycine were used as controls. The magnitudes of the ion currents by the above named herbs were as follows; Cervi cornu>Astragali radix>Aconiti tuber>Zingiberis rhizoma>Ginseng radix>Boshniakiae herba. 2. The magnitudes of the ion currents by $10^{-5}M$ of glutamate pre-treated with 0.01 mg/ml of Bogi, Boyang and Onri herbs were sharply decreased. 3. The activity of ion channels activated by Bogi herbs pre-treated with $10^{-7}M$ of staurosporin, an inhibitor of protein kinase, for thirty seconds was observed as the experiment proceeded. Staurosporin brought about dephosphorylation of ion channels. Hence, while the activity of ion channels activated by Ginseng radix was decreased, the activity of ion channels activated by Astragali radix was increased, as time went by. 4. The activity of ion channels activated by Boyang herbs pre-treated with $10^{-7}M$ of staurosporin, an inhibitor of protein kinase and an dephosphorylating agent of ion channels, for thirty seconds was investigated. While the activity of ion channels activated by Cervi cornu was increased, the activity of ion channels activated by Boshniakiae herba was initially increased then sharply decreased. 5, The activity of ion channels activated by Onri herbs pre-treated with $10^{-7}M$ of staurosporin, an inhibitor of protein kinase and an dephosphorylating agent of ion channels, for thirty seconds was investigated. While the activity of ion channels activated by Aconiti tuber was increased, that of ion channels activated by Zingiberis rhizomal sharply declined.