• 생명과학회지
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• 제27권1호
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• pp.8-14
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• 2017

치자 열매는 아시아에서 음식과 옷의 염료로 사용되어 왔다. 본 연구에서는 BV-2 소교세포에서 치자열매 열수추출물(GJ)의 항염증 효과를 관찰하고 그 작용 기전을 연구하였다. GJ는 세포에 독성을 유도하지 않으면서 lipopolysaccharide로 인한 nitric oxide (NO) 분비와 inducible nitric oxide synthase (iNOS) 생성 및 활성산소 생성을 억제하였다. 또한 GJ는 농도의존적으로 heme oxygenase-1 (HO-1)의 발현을 유도하였다. 더군다나 HO-1 siRNA를 처리했을 때는 GJ가 iNOS의 발현을 억제하지 못하였다. GJ는 HO-1의 발현에 관여하는 전사인자인 nuclear factor E2-related factor 2를 핵으로 이동시켰다. 또한 GJ에 의한 HO-1의 발현은 phosphatidylinositol 3-kinase(PI-3K) 및 p38 kinase 억제제에 의해 감소되었으며, GJ가 Akt와 p38 kinase의 인산화를 유도하였다. 이상의 결과를 종합해보면, GJ는 PI3K/Akt 및 p38 신호전달과정을 통해 HO-1의 발현을 유도함으로써 NO와 같은 염증매개물질의 생성을 억제한다는 것을 알 수 있다. 이러한 연구결과는 치자열매가 신경염증을 억제하는 새로운 기전을 밝힌 것이다.

• Biomolecules & Therapeutics
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• 제23권6호
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• pp.549-556
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• 2015

Consumption of herbal tea [flower buds of Cleistocalyx operculatus (Roxb.) Merr. et Perry (Myrtaceae)] is associated with health beneficial effects against multiple diseases including diabetes, asthma, and inflammatory bowel disease. Emerging evidences have reported that High mobility group box 1 (HMGB1) is considered as a key "late" proinflammatory factor by its unique secretion pattern in aforementioned diseases. Dimethyl cardamonin (2',4'-dihydroxy-6'-methoxy-3',5'-dimethylchalcone, DMC) is a major ingredient of C. operculatus flower buds. In this study, the anti-inflammatory effects of DMC and its underlying molecular mechanisms were investigated on lipopolysaccharide (LPS)-induced macrophages. DMC notably suppressed the mRNA expressions of TNF-${\alpha}$, IL-$1{\beta}$, IL-6, and HMGB1, and also markedly decreased their productions in a time- and dose-dependent manner. Intriguingly, DMC could notably reduce LPS-stimulated HMGB1 secretion and its nucleo-cytoplasmic translocation. Furthermore, DMC dose-dependently inhibited the activation of phosphatidylinositol 3-kinase (PI3K), phosphoinositide-dependent kinase 1 (PDK1), and protein kinase C alpha (PKC${\alpha}$). All these data demonstrated that DMC had anti-inflammatory effects through reducing both early (TNF-${\alpha}$, IL-$1{\beta}$, and IL-6) and late (HMGB1) cytokines expressions via interfering with the PI3K-PDK1-PKC${\alpha}$ signaling pathway.

• Molecules and Cells
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• 제39권4호
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• pp.322-329
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• 2016

Voltage-gated $Ca^{2+}$ ($Ca_V$) channels are dynamically modulated by Gprotein-coupled receptors (GPCR). The $M_1$ muscarinic receptor stimulation is known to enhance $Ca_V2.3$ channel gating through the activation of protein kinase C (PKC). Here, we found that $M_1$ receptors also inhibit $Ca_V2.3$ currents when the channels are fully activated by PKC. In whole-cell configuration, the application of phorbol 12-myristate 13-acetate (PMA), a PKC activator, potentiated $Ca_V2.3$ currents by ~two-fold. After the PMA-induced potentiation, stimulation of $M_1$ receptors decreased the $Ca_V2.3$ currents by $52{\pm}8%$. We examined whether the depletion of phosphatidylinositol 4,5-bisphosphate ($PI(4,5)P_2$) is responsible for the muscarinic suppression of $Ca_V2.3$ currents by using two methods: the Danio rerio voltage-sensing phosphatase (Dr-VSP) system and the rapamycin-induced translocatable pseudojanin (PJ) system. First, dephosphorylation of $PI(4,5)P_2$ to phosphatidylinositol 4-phosphate (PI(4)P) by Dr-VSP significantly suppressed $Ca_V2.3$ currents, by $53{\pm}3%$. Next, dephosphorylation of both PI(4)P and $PI(4,5)P_2$ to PI by PJ translocation further decreased the current by up to $66{\pm}3%$. The results suggest that $Ca_V2.3$ currents are modulated by the $M_1$ receptor in a dual mode-that is, potentiation through the activation of PKC and suppression by the depletion of membrane $PI(4,5)P_2$. Our results also suggest that there is rapid turnover between PI(4)P and $PI(4,5)P_2$ in the plasma membrane.

• The Journal of Korean Physical Therapy
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• 제20권4호
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• pp.35-42
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• 2008

Purpose: Alterations in the structure and function of vascular smooth muscle cells (VSMCs) are important in cardiovascular disease and maintaining chronic hypertension. Chronic hypertension is associated with changes in vascular smooth muscle tone. The spontaneous or myogenic tone of a blood vessel reflects the ability to adapt smooth muscle tone to changes in transmural pressure. However, the intracellular signaling mechanisms involved in myogenic tone are not fully understood. Methods: Here, we investigated the relationship between mitogen-activated protein kinases (MAPKs) and phosphatidylinositol-3 kinase (PI3K) in isometric contraction and enzymatic activity using muscle strips from rats made hypertensive with aldosterone-analogue deoxycorticosterone acetate (DOCA) salts. Results: Changes in myogenic tone and intracellular $Ca^{2+}$ concentration ($[Ca^{2+}]_i$) were different after physiological salt solution (PSS) in normotensive and hypertensive rats. The myogenic tone and quiescent phosphorylation induced by the PSS treatment were inhibited by 10 ${\mu}$M PD098059, an extracellular-regulated protein kinase 1/2 (ERK1/2) inhibitor, and 10 ${\mu}$M wortmannin, an inhibitor of PI3K, in hypertensive rats. Conclusion: The development of DOCA-induced hypertension is associated with altered isometric contractions and $[Ca^{2+}]_i$ via changes in activation of ERK1/2 and PI3K after DOCA-salt treatment. Therefore, ERK1/2 and PI3K activity affect hypertension and may be suitable targets for physical therapy in cardiovascular disease.

• Clinical and Experimental Reproductive Medicine
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• 제39권1호
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• pp.10-14
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• 2012

The ovarian follicles develop initially from primordial follicles. The majority of ovarian primordial follicles are maintained quiescently as a reserve for the reproductive life span. Only a few of them are activated and develop to an advanced follicular stage. The maintenance of dormancy and activation of primordial follicles are controlled by coordinated actions of a suppressor/activator with close communications with somatic cells and intra-oocyte signaling pathways. Many growth factors and signaling pathways have been identified and the transforming growth factor-beta superfamily plays important roles in early folliculogenesis. However, the mechanism of maintaining the dormancy and survival of primordial follicles has remained unknown for decades. Recently, since the first finding that all primordial follicles are activated prematurely in mice deficient forkhead box O3a, phosphatidylinositol 3 kinase/phosphatase and tensin homolog (PTEN) signaling pathway was reported to be important in the regulation of dormancy and initial follicular activation. With these informations on early folliculogenesis, clinical application can be expected such as in vitro maturation of immature oocytes or in vitro activation of follicles by PTEN inhibitor in cryopreserved ovarian cortical tissues for fertility preservation.

• Journal of Ginseng Research
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• 제41권1호
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• pp.96-102
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• 2017

Background: Korean ginseng, Panax ginseng Meyer, has been used as a traditional oriental medicine to treat illness and promote health for several thousand years. Ginsenosides are the main constituents for the pharmacological effects of P. ginseng. Since several ginsenosides, including ginsenoside (G)-Rg3 and G-Rp1, have reported antiplatelet activity, here we investigate the ability of G-Rp4 to modulate adenosine diphosphate (ADP)-induced platelet aggregation. The ginsenoside Rp4, a similar chemical structure of G-Rp1, was prepared from G-Rg1 by chemical modification. Methods: To examine the effects of G-Rp4 on platelet activation, we performed several experiments, including antiplatelet ability, the modulation of intracellular calcium concentration, and P-selectin expression. In addition, we examined the activation of integrin ${\alpha}IIb{\beta}_3$ and the phosphorylation of signaling molecules using fibrinogen binding assay and immunoblotting in rat washed platelets. Results: G-Rp4 inhibited ADP-induced platelet aggregation in a dose-dependent manner. We found that G-Rp4 decreased calcium mobilization and P-selectin expression in ADP-activated platelets. Moreover, fibrinogen binding to integrin ${\alpha}IIb{\beta}_3$ by ADP was attenuated in G-Rp4-treated platelets. G-Rp4 significantly attenuated phosphorylation of extracellular signal-regulated protein kinases 1 and 2, p38, and c-Jun N-terminal kinase, as well as protein kinase B, phosphatidylinositol 3-kinase, and phospholipase C-${\gamma}$ phosphorylations. Conclusion: G-Rp4 significantly inhibited ADP-induced platelet aggregation and this is mediated via modulating the intracellular signaling molecules. These results indicate that G-Rp4 could be a potential candidate as a therapeutic agent against platelet-related cardiovascular diseases.

• 생명과학회지
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• 제22권12호
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• pp.1621-1627
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• 2012

세포의 이동은 성장, 면역 작용, 그리고 혈관 신생 등 많은 생리현상에 중요한 역할을 한다. 또한 염증 및 종양 세포 침윤 등의 다양한 병리적 현상과도 밀접한 연관이 있다. 본 연구에서는 lysophosphatidic acid (LPA)는 활성산소의 생성을 통해 SKOV-3 난소암세포의 이동을 조절한다는 것을 관찰하였다. 먼저, 난소 암세포인 SKOV-3에서 LPA에 의한 세포의 이동이 강하게 일어남을 확인하였다. LPA에 의한 SKOV-3 세포의 이동은 phosphatidylinositol 3-kinase (PI3K)/Akt 신호전달체계를 저해시키는 약물에 의해서 완벽히 억제됨을 확인하였으나 ERK 신호전달체계를 저해시키는 약물에 의해서는 전혀 영향을 받지 않았다. 그리고 SKOV-3 세포에서 LPA에 의한 활성산소 형성이 시간에 따라 강하게 일어남을 확인하였다. 더욱이 LPA에 의한 활성산소 형성도 PI3K 또는 Akt의 저해제에 의해서 완벽히 억제됨을 확인하였으나 ERK 신호전달을 억제하였을 때는 거의 영향을 받지 않았다. SKOV-3 세포에서 LPA에 의해 생성된 활성산소는 diphenylene idonium (DPI, $10{\mu}M$), apocyanin (Apo, $10{\mu}M$)과 같은 NADPH oxidase 억제제를 전 처리하였을 때 활성산소가 형성되지 못함을 관찰하였다. 그러나 xanthine oxidase (allopurinol, Allo, $10{\mu}M$), cyclooxygenase (indomethacin, Indo, $10{\mu}M$), 또는 mitochondrial respiratory chain complex I (rotenone, Rot, $10{\mu}M$)를 억제하였을 때는 LPA에 의한 활성산소 형성에 영향을 주지 못함을 확인하였다. 마지막으로 활성산소 억제제인 N-acetylcysteine (NAC, $10{\mu}M$)에 의해서 LPA에 의한 암세포의 이동이 억제됨을 관찰하였다. 이와 더불어 LPA에 의한 SKOV-3 세포의 이동도 NADPH oxidase 억제에 의해 저해가 됨을 확인하였다. 이러한 연구결과로 보아 LPA에 의한 활성산소의 형성에는 PI3K/Akt/NADPH oxidase 신호전달체계가 중추적인 역할을 하며 이를 통해 암세포의 이동을 조절한다는 것을 알 수 있었다.

• 환경위생공학
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• 제14권1호
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• pp.88-96
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• 1999

The effect of acute cadmium-neuropathy on phospholipid metabolism in rat sciatic nerve was investigated. An animal model of cadmium neuropathy was induced by feeding diet containing cadmium to Sprague-Dawley rat for two weeks. Four weeks aged Sprague-Dawley rats were divided into four groups : normal control group, 10ppm-cadmium treated group, 100ppm-cadmium treated group, 1000ppm-cadmium treated group, reference drug, myo-inositol-treated group. All rats were sacrificed at the end of two weeks. The rate of incorporation of 2-[3H]myo-inositol into polyphosphinositide was significantly decreased while the rates of incorporation into phospholipid of titratedserine, ethanolamine and choline were unchanged in sciatic nerve obtained from cadmium-treated rat. Continuously the activities of three enzymes concerned with inositol phospholiped metabolism were measured in homogenates of rat sciatic nerves. Cystidine diglyceride transferase and phophatidylinositol kinase showed significantly decreased activities while phosphatidylinositol-4-phosphate kinase did not show any significant change in activity by cadmium treatment. However these deficits of inositol phospholipid metabolism were ameliorated by myo-inositol administration and these effectiveness were more potent in lower dose cadmiumtreated rats than higher dose cadmium-treated rats. These results suggest that cadmium intoxicated peripheral nerve with perturbation of the ployphosphoinositide metabolism and alteration of the enzyme activity which concerned with myo-inositol metabolism.

• BMB Reports
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• 제47권7호
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• pp.361-368
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• 2014

Lipid components in biological membranes are essential for maintaining cellular function. Phosphoinositides, the phosphorylated derivatives of phosphatidylinositol (PI), regulate many critical cell processes involving membrane signaling, trafficking, and reorganization. Multiple metabolic pathways including phosphoinositide kinases and phosphatases and phospholipases tightly control spatio-temporal concentration of membrane phosphoinositides. Metabolizing enzymes responsible for PI 4,5-bisphosphate (PI(4,5)P2) production or degradation play a regulatory role in Toll-like receptor (TLR) signaling and trafficking. These enzymes include PI 4-phosphate 5-kinase, phosphatase and tensin homolog, PI 3-kinase, and phospholipase C. PI(4,5)P2 mediates the interaction with target cytosolic proteins to induce their membrane translocation, regulate vesicular trafficking, and serve as a precursor for other signaling lipids. TLR activation is important for the innate immune response and is implicated in diverse pathophysiological disorders. TLR signaling is controlled by specific interactions with distinct signaling and sorting adaptors. Importantly, TLR signaling machinery is differentially formed depending on a specific membrane compartment during signaling cascades. Although detailed mechanisms remain to be fully clarified, phosphoinositide metabolism is promising for a better understanding of such spatio-temporal regulation of TLR signaling and trafficking.

• Asian Pacific Journal of Cancer Prevention
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• 제15권21호
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• pp.9327-9333
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• 2014

Breast cancer is the second most common cancer and second leading cause of cancer deaths in women. Phosphatidylinositol-3-kinase (PI3K)/AKT pathway mutations are associated with cancer and phosphatidylinositol-4, 5-bisphosphate 3-kinase catalytic subunit alpha (PIK3CA) gene mutations have been observed in 25-45% of breast cancer samples. Insulin growth factor binding protein-5 (IGFBP-5) can show different effects on apoptosis, cell motility and survival in breast cancer. We here aimed to determine the association between PIK3CA gene mutations and IGFBP-5 expressions for the first time in breast cancer patients. Frozen tumor samples from 101 Turkish breast cancer patients were analyzed with high resolution melting (HRM) for PIK3CA mutations (exon 9 and exon 20) and 37 HRM positive tumor samples were analyzed by DNA sequencing, mutations being found in 31. PIK3CA exon 9 mutations (Q546R, E542Q, E545K, E542K and E545D) were found in 10 tumor samples, exon 20 mutations (H1047L, H1047R, T1025T and G1049R) in 21, where only 1 tumor sample had two exon 20 mutations (T1025T and H1047R). Moreover, we detected one sample with both exon 9 (E542Q) and exon 20 (H1047R) mutations. 35% of the tumor samples with high IGFBP-5 mRNA expression and 29.4% of the tumor samples with low IGFBP-5 mRNA expression had PIK3CA mutations (p=0.9924). This is the first study of PIK3CA mutation screening results in Turkish breast cancer population using HRM analysis. This approach appears to be a very effective and reliable screening method for the PIK3CA exon 9 and 20 mutation detection. Further analysis with a greater number of samples is needed to clarify association between PIK3CA gene mutations and IGFBP-5 mRNA expression, and also clinical outcome in breast cancer patients.