• Archives of Pharmacal Research
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• 제21권2호
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• pp.164-167
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• 1998

Bis-${\gamma}$-lactones (1,2) having a perhydrofuro[3,4-c]furan-1,4-dione skeleton were designed as conformationally constrained diacylglycerol analogues. They were synthesized from D-apiose in 11 steps, and evaluated as $PKC-{\alpha}$ ligands by measuring their ability to displace bound $^3H$]PDBU from the enzyme. The compounds showed moderate binding affinities with $K_i$ values of 13.89 (${\pm}5.67$) ${\mu}M$ and 11.47 (${\pm}0.89$) ${\mu}M$, respectively. Their similar binding affinities indicate that these two bicyclic compounds were not effectively discriminated by $PKC-{\alpha}$ in terms of the direction of the side chain as other ligands built on similar bis-${\gamma}$-lactones.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제23권4호
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• pp.295-305
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• 2001

구강은 흡연이나 음주와 같은 화학적 발암물질이 쉽게 접촉할 수 있는 화학적 발암물질의 표적장기이며 구강암을 포함한 대부분의 암 발생의 근원이 되는 세포는 상피세포이다. 따라서 본 연구는 인체상피세포를 화학적 발암물질인 MNING에 노출시켜 발암화를 유도하고 이에 따른 작용 기전을 분석함으로써 구강암과 같은 상피세포 기원의 종양 발생기전을 이해하는 데 기여하고자 하였다. 인체 상피세포에 $0.001{\mu}g/ml$에서 $1{\mu}g/ml$ 용량의 MNNG를 투여한 결과 용량 의존적인 세포발암성을 나타내었으며 $0.01{\mu}g/ml$ 투여군이 가장 높은 암세포의 지표를 보였다. MNNG투여후 TPA를 처리한 결과 발암세포의 지표인 saturation density, soft agar colony formation, cell aggregation 등에서 MNNG의 단독 투여시보다 높은 발암성을 나타내었으며 최초의 foci출현시기도 단축되었다. 이와같은 결과는 Phorbol ester binding assay에서도 나타나 세포 발암화 촉진에 PKC활성이 관여함을 추정할 수 있다. PKC translocation 현상은 세포외 칼슘이 있을 경우에만 나타나 MNNG에 의한 PKC활성에 classical PKC가 관여함을 추정할 수 있었다. MNNG에 대한 초기반응으로 cPKC의 경우 $PKC-{\alpha}$와 $PKC-{\gamma}$가 고농도에서 활성의 증가를 보였으며 nPKC의 경우 $PKC-{\varepsilon}$가 뚜렷한 활성을 보여 이들 isoform이 MNNG에 의한 발암화 초기단계에 관여함을 암시하였다. 반면 aPKC는 어느 형태도 MNNG에 반응하지 않아 화학적 발암화 과정에 isoform의 특이성이 존재함을 입증하였다. MNNG에 의해 발암화 특성을 나타낸 세포는 $PKC-{\alpha}$ 및 $PKC-{\gamma}$의 지속적인 활성증가를 나타내어 발암의 초기단계부터 지속적이 활성을 유지하고 있는 isoform으로 추정된다. 본 연구결과 인체상피 세포의 모든 PKC isoform에 대한 발현을 분석하고 화학적 발암화에 관여하는 isoform을 선별해냄으로써 특정한 inhibitor 등을 상요한 발암화 억제제의 개발에 필요한 기초자료를 제공하였을 뿐만 아니라 구강암과 같은 상피세포 기원의 암발생 기전을 이해하는 데 기여할 것으로 사료된다.

• 한국응용약물학회:학술대회논문집
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• 한국응용약물학회 1993년도 제2회 신약개발 연구발표회 초록집
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• pp.135-135
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• 1993

신호전달과정에 중요한 역할을 하고 있는 다기능 serinei/threonine 단백질인산화효소인 protein kinase C(PKC)의 연구를 위해 이 효소의 정제를 뇌에서 착수하였다 PKC의 활성측정을 myelin basic protein을 기질로 하여 20 mM Tris 완충용액 PH 7.5, 0.15 mM [${\gamma}$-$^{32}$P]ATP(3 $\times$ $10^{5}$ cpm), 0.1 mM $Ca^{2＋}$, 10$\mu\textrm{g}$ phosphatidylserine과 2$\mu\textrm{g}$ diolein을 넣어 반응시켰다. 반응은 TCA로 정지시킨 후 방사성 단백질을 Millipore filter paper로 걸러 섬광 계수기로 읽었다. Cytosol PKC의 정제과정은 첫 단계에서 DEAE-cellulose를 사용하였으며, phenyl sepharose CL-4B와 protamine agarose를 연속적으로 이용하여 800배의 정제에 성공했다. SDS-PACE 상에서 80 kD로 나타났으며 순도는 95 % 이상이였다. 이를 이용 PKC의 각종 기질 연구에 착수하기 시작했으며, 이중 MBP의 인산화연구를 통한 myelin의 안정성과 MBP와의 구조 관계가 일부 수행되고 있다 연차적으로 PKC와 이와 관련된 단백질의 특성을 살피기 위해 뇌의 PKC 기질 중 cold stress를 통해 환경에 민감한 것을 찾고 있으며, 현재 autoradiography를 이용해 80 kD, 54 kD, 49 kD와 35 kD의 단백질이 연구대상이 되고있다. 그 중 49 kD는 B-50(또는 GAP43, neuromodulin이라고도 함)일 가능성이 높아 이 단백질 조절과 PKC 활성화 사이의 관계 정립이 흥미로운 과제로 대두되고 있다.다.

• The Korean Journal of Physiology and Pharmacology
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• 제5권1호
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• pp.55-63
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• 2001

In macrophages, lipopolysaccharide (LPS) alone or in combination with $interferon-{\gamma}\;(IFN-{\gamma})$ has been shown to release a nitric oxide (NO) through the increase of the transcription of the inducible nitric oxide synthase (iNOS) gene. To investigate the exact intracellular signaling pathway of the regulation of iNOS gene transcription by LPS plus $IFN-{\gamma},$ the effects of protein tyrosine kinase (PTK) inhibitor and protein kinase C (PKC) inhibitors on NO production, iNOS mRNA expression, nuclear $factor-_{\kappa}B\;(NF-_{\kappa}B)$ binding activity and the promoter activity of iNOS gene containing two $NF-_{\kappa}B$ sites have been examined in a mouse macrophage RAW 264.7 cells. LPS or $IFN-{\gamma}$ stimulated NO production, and their effect was enhanced synergistically by mixture of LPS and $IFN-{\gamma}.$ The PTK inhibitor such as tyrphostin reduced LPS plus $IFN-{\gamma}-induced$ NO production, iNOS mRNA expression and $NF-_{\kappa}B$ binding activity. In contrast, PKC inhibitors such as H-7, Ro-318220 and staurosporine did not show any effect on them. In addition, transfection of RAW 264.7 cells with iNOS promoter linked to a CAT reporter gene revealed that tyrphostin inhibited the iNOS promoter activity through the $NF-_{\kappa}B$ binding site, whereas PKC inhibitors did not. Taken together, these suggest that PTK, but not PKC pathway, is involved in the regulation of the iNOS gene transcription through the $NF-_{\kappa}B$ sites of iNOS promoter in RAW 264.7 macrophages by LPS plus $IFN-{\gamma}$.

• BMB Reports
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• 제32권4호
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• pp.339-344
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• 1999

We studied the effects of ginsenosides in immature rats based upon the previous results that ginseng has a suppressive or anticonvulsive activity. To examine the suppressive effect of ginsenosides on kainic acid-induced seizures, the severities and frequencies were observed for 4 h after injection of kainic acid (KA; i.p., 2 mg/kg b.w.) using 10-day-old male Sprague-Dawley rats ($22{\pm}2\;g$). Protopanaxadiol saponins such as ginsenoside-Rb1 (Rb1), ginsenoside-Rb2 (Rb2), ginsenoside-Rc (Rc), and ginsenoside-Rd(Rd) generally reduced the seizure activities while protopanaxatriol saponins such as ginsenoside-Rg1 (Rg1) and ginsenoside-Re (Re) rather increased stereotypic "paddling-like" movements. When vinyl-GABA (v-G) was injected together with Rb1 or Rc, KA-induced seizure severities were additionally reduced only by the injection of Rc, but not by Rb1. The level of gamma isozyme of protein kinase C (PKC-${\gamma}$) in the hippocampus increased about three times as much as that of normal rats at 4 h after KA injection. The increased level of PCK-${\gamma}$ by KA was significantly reduced to about 35% by the coinjection with v-G alone, but it was not changed by v-G together with Rb1 or Rc. The increased level of PKC-${\gamma}$ at 4 h after injection of KA was not consistent with the reduction of seizure severities between Rb1 and Rc. These results suggest that Rc and Rb1 may reduce seizure severity independent of PKC-${\gamma}$ levels, and Rc may additionally act with v-G regarding the GABA metabolism during the stage of KA-induced seizures in the immature rats.

• Journal of Yeungnam Medical Science
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• 제36권1호
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• pp.26-35
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• 2019

Background: Dysregulation of hepatic glucose production (HGP) contributes to the development of type 2 diabetes mellitus. Telmisartan, an angiotensin II type 1 receptor blocker (ARB), has various ancillary effects in addition to common blood pressure-lowering effects. The effects and mechanism of telmisartan on HGP have not been fully elucidated and, therefore, we investigated these phenomena in hyperglycemic HepG2 cells and high-fat diet (HFD)-fed mice. Methods: Glucose production and glucose uptake were measured in HepG2 cells. Expression levels of phosphoenolpyruvate carboxykinase (PEPCK) and glucose-6-phosphatase ${\alpha}$ ($G6Pase-{\alpha}$), and phosphorylation levels of insulin receptor substrate-1 (IRS-1) and protein kinase C ${\zeta}$ ($PKC{\zeta}$) were assessed by western blot analysis. Animal studies were performed using HFD-fed mice. Results: Telmisartan dose-dependently increased HGP, and PEPCK expression was minimally increased at a $40{\mu}M$ concentration without a change in $G6Pase-{\alpha}$ expression. In contrast, telmisartan increased phosphorylation of IRS-1 at Ser302 ($p-IRS-1-Ser^{302}$) and decreased $p-IRS-1-Tyr^{632}$ dose-dependently. Telmisartan dose-dependently increased $p-PKC{\zeta}-Thr^{410}$ which is known to reduce insulin action by inducing IRS-1 serine phosphorylation. Ectopic expression of dominant-negative $PKC{\zeta}$ significantly attenuated telmisartan-induced HGP and $p-IRS-1-Ser^{302}$ and -inhibited $p-IRS-1-Tyr^{632}$. Among ARBs, including losartan and fimasartan, only telmisartan changed IRS-1 phosphorylation and pretreatment with GW9662, a specific and irreversible peroxisome proliferator-activated receptor ${\gamma}$ ($PPAR{\gamma}$) antagonist, did not alter this effect. Finally, in the livers from HFD-fed mice, telmisartan increased $p-IRS-1-Ser^{302}$ and decreased $p-IRS-1-Tyr^{632}$, which was accompanied by an increase in $p-PKC{\zeta}-Thr^{410}$. Conclusion: These results suggest that telmisartan increases HGP by inducing $p-PKC{\zeta}-Thr^{410}$ that increases $p-IRS-1-Ser^{302}$ and decreases $p-IRS-1-Tyr^{632}$ in a $PPAR{\gamma}$-independent manner

• 대한의생명과학회지
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• 제16권2호
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• pp.119-122
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• 2010

Interleukin-1${\beta}$ $(IL-1{\beta})$ is one of the key proinflammatory cytokines and it plays an important role for the antimycobacterial host defense mechanisms. In this study, we examined Mycobacterium tuberculosis (MTB)-stimulated induction of IL-1${\beta}$ and evaluated the associated signal transduction pathways. In PMA-differentiated THP-1 cells, MTB infection increased mRNA expression of IL-$1{\beta}$ in a dose-dependent manner. The expression of IL-1${\beta}$ mRNA began to be induced at 1.5 h after infection, and induced expression of IL-1${\beta}$ was retained for 48 h after MTB infection. The increase in expression of IL-1${\beta}$ caused by MTB was reduced in cells treated with Ro-31-8425 (an inhibitor of PK$C{\alpha}$, ${\beta}I$, ${\beta}II$, ${\gamma}$, ${\varepsilon}$) or PD98059 (an inhibitor of MEK1), meanwhile, pre-treatment with $G\ddot{o}6976$ (an inhibitor of $Ca^{2+}$ dependent PK$C{\alpha}$ and PK$C{\beta}I$) or Rottlerin (an inhibitor of PK$C{\delta}$) has no effect on MTB-induced expression of $IL-1{\beta}$ mRNA. These results show that the expression of $IL-1{\beta}$ mRNA caused by MTB may be mediated via MEK1 and PKC isoforms including PK$C{\beta}II$, $PKC{\gamma}$, or $PKC{\varepsilon}$. Further studies are required to determine whether other PKC isoforms $(PKC {\eta},\;{\theta},\;{\varepsilon},\;and\;{\lambda}/{\iota})$, except $PKC{\delta}$, $PKC{\alpha}$, and $PKC{\beta}I$, are also involved in $IL-1{\beta}$ mRNA expression after mycobacterial infection.

• 고려인삼학회:학술대회논문집
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• 고려인삼학회 1998년도 Advances in Ginseng Research - Proceedings of the 7th International Symposium on Ginseng -
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• pp.244-252
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• 1998

Ginsenoside Rh, (G-Rh,) from Panax ginseng induced morphological features of apoptosis and DNA fragmentation as a biochemical marker of apoptosis confirmed by TUNEL reaction and agarose gel electrophoresis in human neuroblastoma SK-N-BE(2) and rat glioma C6Bu-1 cells During apoptosis by G-Rh2, protein kinase C (PKC) isoforms were analysed by immunoblotting. In SK-N-BE(2) cells, the levels of a, p and ${\gamma}$ subtypes were increased by undergoing apoptosis, while PKC e isoform increased early in treatment (3 h and 6 h). In addition, PKC s isoform gradually decreased during apoptosis by G-Rh2 and PKC $\theta$ isoform was detected in neither untreated- nor G-Rh1-treated SK-N-BE(2) cells (data not shown). However, no significant changes in the level of S and s isoforms were observed in C6Bu-1 cells undergoing apoptosis by G-Rh2. These results suggest that PKC subtypes may play differential roles in apoptotic signal pathways and their roles can be cell type-specific in apoptosis induced by G-Rh2.

• 동의생리병리학회지
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• 제25권1호
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• pp.29-36
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• 2011

Nardostachyts chinensis (N. chinensis) belonging to the family Valerianaceae has been used to elicit stomachic and sedative effects. The MAPKs are serine/threonine kinases involved in the regulation of various cellular responses, such as cell proliferation, differentiation and apoptosis. The PKC also plays a key role in regulating the response of hematopoietic cells to both physiological and pathological inducers of proliferation and differentiation. This study investigated the signaling pathways on the U937 cell differentiation induced by N. chinensis. N. chinensis induced the differentiation of U937 cells, as shown by increased of differentiation surface antigen CD11b. Activation of ERK increased time-dependently in differentiation of U937 cells induced by N. chinensis, but activations of JNK and p38 were unaffected. Inhibitor of ERK (PD98059) significantly reduced CD11b expression induced by N. chinensis in U937 cells. In addition, N. chinensis increased protein level of PKC ${\beta}$I and PKC ${\beta}$II isoforms, but the protein level of PKC ${\alpha}$ and PKC ${\gamma}$was constant. PKC inhibitors (GF 109203X and H-7) inhibited U937 cell differentiation and the ERK activation induced by N. chinensis. These results indicated that PKC and ERK may be involved in U937 cell differentiation induced by N. chinensis.

• Environmental Analysis Health and Toxicology
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• 제15권3호
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• pp.69-80
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• 2000

ADP-rubosylation may be involved in the process of macrophage activation. Nitric oxide (NO) has emerged as an important intracellular and interacellular regulatory molecule with function as diverse as vasodilation, neural communication or host defense. NO is derived from the oxidation of the terminal guanidino nitrogen atom of L-arginine by the NADPH -dependent enzyme, nitric oxide synthase (NOS) which is one of the three different isomers in mammalian tissues. Since NO can exert protective or regulatory functions in the cell at a low concentration while toxic effects at higher concentrations, its role may be tightly regulated in the cell. Therefore, this paper was focused on signal transduction pathway of NO synthesis, role of endogenous TGF-$\beta$ in NO production. effect of NO on superoxide formation. Costimulation of murine peritoneal macrophages with interferon-gamma (IFN-γ) and phorbol 12-myristate 13-acetate (PMA) increased both NO secretion and mRNA expression of inducible nitric oxide synthase (iNOS) when PMA abolished costimulation. Pretreatmnet of the cells with PMA abolished costimuation effects due to the depletion of protein kinase C (PKC) activities . The involvement of PKC in NO secretion could be further confirmed by PKC inhibitor, stauroprine, and phorbol ester derivative, phorbol 12,13-didecanoate. Addition of actinomycine D in IFN-γ plus PMA stimulated cells inhibited both NO secretion and mRNA expression of iNOS indication that PMA stabilizes mRNA of iNOS . Exogenous TGF-$\beta$ reduced NO secretion in IFN -γ stimulated murine macrophages. However addition of antisense oligodeoxynucleotide (ODN) to TGF-$\beta$ to this system recovered the ability of NO production and inhibited mRNA expression of TGF-$\beta$. ACAS interactive laser cytometry analysis showed that transportation of FITC -labeled antisense ODN complementary to TGF-$\beta$ mRNA could be observed within 5 min and reached maximal intensity in 30 min in the murine macrophage cells. NO released by activated macrophages inhibits superoxide formation in the same cells . This inhibition nay be related on NO-induced auto -adenosine diphosphate (ADP) -ribosylation . In addition, ADP-ribosylation may be involved in the process of macrophage activation .