• 한국동물학회지
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• 제39권3호
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• pp.266-272
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• 1996

봄에 채집한 참개구리의 난소조각 배양계를 사용하여 난자의 배란과정에 프로스타글란딘과 protein kinase C(PKC)가 관여하는 지를 조사하였다. 난소조각을 배양하면서 뇌하수체추출물(FPH) 혹은PKC의 활성제인 12-O-tetradecanoyl phorbol-13-acetate (TPA)를 처리한 후 배란율과 프로스타글란딘의 생상량을 방사면역측정법으로 조사한 결과 농도에 의존하여 난자의 배란이 유도 되었으며 프로스타글란딘의 생성이 촉진되었다. FPH와 TPA에 의한 배란과 프로스타글란딘 생성은, 4월 보다는 5월에 채집한 개구리에서 훨씬 더 효과적이었다. FPH처리는 프로스타글란딘과 함께 progestreone의 생성을 촉진하였으나 TPA는 progestreone의 생성을 촉진하지는 못하였다. FPH와 TPA에 의한 배란과ㅣ 프로스타글라딘 생성 억제제인 indomethacin에 의해서는 난자의 배랑니 억제되지는 않았다. 이러한 결과들은 참개구리 난자의 배란 과정에 PKC의 활성화가 중요한 역할을 하며, 프로스타글라딘의 생성이 매개할 것으로 생각된다.

• 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 .

• 대한의생명과학회지
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• 제12권3호
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• pp.249-254
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• 2006

It has been reported that liver is a very important organ to xenotransplantation. Pig is known to be a most suitable species in transplantation of human organs. However, the physiological function of pig hepatocytes is not clear elucidated. Epidermal growth factor (EGF) is known to be a mitogen in various cell systems. Thus, we examined the effect of EGF on cell proliferation and its related signal cascades in primary cultured pig hepatocytes. EGF stimulates cell proliferation in a dose (>1ng/ml) dependent manner. EGF-induced increase of $[^3H]-thymidine$ incorporation was blocked by AG 1478 ($10^{-6}M$, an EGF receptor antagonist) genistein and herbymycin A (tyrosine kinase inhibitors, $10^{-6}M$), suggesting the role of activation and tyrosine phosphorylation of EGF receptor. In addition, EGF-induced increase of $[^3H]-thymidine$ incorporation was prevented by neomycin $(10^{-4}M)$, U73122 $(10^{-5}M)$ (phospholipase C [PLC] inhibitors), staurosporine ($(10^{-8}M)$, or bisindolylmaleimide I $(10^{-6}M)$ (protein kinase C [PKC] inhibitors), suggesting the role of PLC and PKC. Moreover, EGF-induced increase of $[^3H]-thymidine$ incorporation was blocked by PD 98059 (a p44/42 mitogen activated protein kinase [MAPK] inhibitor), SB 203580 (a p38 MAPK inhibitor), and SP 600125 (a JNK inhibitor). EGF increased the translocation of PKC from cytosol to membrane fraction and activated p42/44 MAPK, p38 MAPK and JNK. In conclusion, EGF stimulates cell proliferation via PKC and MAPK in cultured pig hepatocytes.

• 한국응용약물학회:학술대회논문집
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• 한국응용약물학회 2003년도 Annual Meeting of KSAP : International Symposium on Pharmaceutical and Biomedical Sciences on Obesity
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• pp.78-78
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• 2003

Inulin, an active component of Chicorium intybus root, has been shown to stimulate the growth of bifidobacteria, and inhibit colon carcinogenesis. NO mediates a number of the host-defense functions of activated macrophages, including antimicrobial and tumoricidal activity. We examined the effect of inulin on the synthesis of NO in RAW 264.7 cells. Inulin alone had no effect, whereas inulin with IFN-ν synergistically increased the NO production and inducible NO synthase (iNOS) expression in RAW 264.7 cells. Synergy between IFN-ν and inulin was mainly dependent on inulin-induced TNF-${\alpha}$ secretion. Also, protein kinase C (PKC)-${\alpha}$ was involved in the inulin-induced NO production. Inulin-mediated NO production was inhibited by the protein tyrosine kinase (PTK) inhibitor, tyrphostin AG126. Since iNOS gene transcriptions have been shown to be under the control of the NF -$\kappa$B/Rel family of transcription factors, we assessed the effect of inulin on NF -$\kappa$B/Rel using an EMSA. Inulin produced strong induction of NF-$\kappa$B/Rel binding, whereas AP-l binding was slightly induced in RAW 264.7 cells. Inulin stimulated phosphorylation and degradation of I$\kappa$B-${\alpha}$. These results suggest that in IFN-ν-primed RAW 264.7 cells inulin might stimulate NO synthesis via activation of PKC-${\alpha}$ and PTK, resulting in the activation of NF-$\kappa$B.

• Molecules and Cells
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• 제24권2호
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• pp.224-231
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• 2007

$H_2O_2$, as an example of oxidative stress, induces cardiac myocyte apoptosis. Bcl-2 family proteins are key regulators of the apoptotic response while their functions can be regulated by post-translational modifications including phosphorylation, dimerization or proteolytic cleavage. In this study, we examined the role of various protein kinases in regulating total BAD protein levels in adult rat cardiac myocytes undergoing apoptosis. Stimulation with 0.1 mM $H_2O_2$, which induces apoptosis, resulted in a marked down-regulation of BAD protein, which is attributed to cleavage by caspases since it can be restored in the presence of a general caspase inhibitor. Inhibition of PKC, p38-MAPK, ERK1/2 and PI-3-K did not influence the reduced BAD protein levels observed after stimulation with $H_2O_2$. On the contrary, inhibition of PKA or specifically $PKC{\delta}$ resulted in up-regulation of BAD. Decreased caspase 3 activity was observed in $H_2O_2$ treated cells after inhibition of PKA or $PKC{\delta}$ whereas inhibition of PKA also resulted in improved cell survival. Furthermore, addition of okadaic acid to inhibit selected phosphatases resulted in enhanced BAD cleavage. These data suggest that, during oxidative stress-induced cardiac myocyte apoptosis, there is a caspase-dependent down-regulation of BAD protein, which seems to be regulated by coordinated action of PKA, $PKC{\delta}$ and phosphatases.

• Journal of Ginseng Research
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• 제44권2호
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• pp.274-281
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• 2020

Background: Ultraviolet (UV) goes through the epidermis and promotes release of inflammatory cytokines in keratinocytes. Granulocyte-macrophage colony-stimulating factor (GM-CSF), one of the keratinocyte-derived cytokines, regulates proliferation and differentiation of melanocytes. Extracellular signal-regulated kinase (ERK1/2) and protein kinase C (PKC) signaling pathways regulate expression of GM-CSF. Based on these results, we found that ginsenoside Rh3 prevented GM-CSF production and release in UV-B-exposed SP-1 keratinocytes and that this inhibitory effect resulted from the reduction of PKCδ and ERK phosphorylation. Methods: We investigated the mechanism by which ginsenoside Rh3 from Panax ginseng inhibited GM-CSF release from UV-B-irradiated keratinocytes. Results: Treatment with 12-O-tetradecanoylphorbol-13-acetate (TPA) or UV-B induced release of GM-CSF in the SP-1 keratinocytes. To elucidate whether the change in GM-CSF expression could be related to PKC signaling, the cells were pretreated with H7, an inhibitor of PKC, and irradiated with UV-B. GM-CSF was decreased by H7 in a dose-dependent manner. When we analyzed which ginsenosides repressed GM-CSF expression among 15 ginsenosides, ginsenoside Rh3 showed the largest decline to 40% of GM-CSF expression in enzyme-linked immunosorbent assay. Western blot analysis showed that TPA enhanced the phosphorylation of PKCδ and ERK in the keratinocytes. When we examined the effect of ginsenoside Rh3, we identified that ginsenoside Rh3 inhibited the TPA-induced phosphorylation levels of PKCδ and ERK. Conclusion: In summary, we found that ginsenoside Rh3 impeded UV-B-induced GM-CSF production through repression of PKCδ and ERK phosphorylation in SP-1 keratinocytes.

• 대한약리학회지
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• 제31권2호
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• pp.145-152
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• 1995

The effects and interactions of $4{\beta}-phorbol$ 12,13-dibutyrate(PDB) and polymyxin B(PMB) with adenosine on the electrically-evoked norepinephrine (NE) release were studied in the rat hippocampus. Slices from the rat hippocampus were equilibrated with $^3H-noradrenaline$ and the release of the labelled product, $^3H-NE$, which evoked by electrical stimulation$(3\;Hz,\;2\;ms,\;5\;VCm^{-1},\;rectangular\;pulses)$ was measured. PDB$(0.3{\sim}10\;{\mu}M)$, a selective protein kinase C(PKC) activator, increased the evoked NE release in a dose related fashion while increasing the basal rate of release. And the effects of $1\;{\mu}M$ PDB were significantly inhibited by $0.3\;{\mu}M$ tetrodotoxin(TTX) pretreatment or $Ca^{++}-free$ medium. $PMB(0.03{\sim}1\;mg)$, a specific PKC inhibitor, decreased the NE release in a dose dependent manner while increasing the basal rate of release. Adenosine $(1{\sim}10\;{\mu}M)$ decreased the NE release without changing the basal rate of release, and this effect was significantly inhibited by 8-cyclopentyl-1,3-dipropylxanthine$(2\;{\mu}M)$, a selective $A_1-receptor$ antagonist, treatment. Also, adenosine effects were significantly inhibited by PDB-and PMB-pretreatment. These results suggest that the PKC plays a role in the NE release in the rat hippocampus and might be participated in a post-receptor mechanism of the $A_1-adenosine$ receptor.

• Clinical and Experimental Pediatrics
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• 제45권6호
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• pp.732-742
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• 2002

목 적: 저산소-허혈에 대한 신경독성의 규명 및 xanthine oxidase inhibitor인 allopurinol의 저산소성-허혈 유도에 미치는 방어효과를 조사하기 위하여 본 연구를 시도하였다. 방 법: 신생쥐에 우측 총경동맥을 결찰 및 8% O2의 노출로 허혈 및 저산소 상태를 만든 후 저산소성-허혈이 12-72시간 동안 대뇌의 neuron과 astrocyte에 미치는 영향을 조사하여 신경독성을 규명하고, 또한 xanthine oxidase inhibitor인 allopurinol이 저산소성-허혈 유도에 미치는 영향을 조사하기 위하여 저산소성-허혈 유도 15분 전에 150 mg/kg의 allopurinol을 복강 투여한 다음 투여 후 14일 후에 신생쥐를 희생하여 이의 뇌 조직으로부터 순수분리 배양한 신경 세포에 대하여 세포의 수적 변화와 생존율을 비롯하여 LDH와 단백질합성 및 PKC를 조사하였다. 결 과 : 1) 저산소성-허혈은 저산소-허혈 유도 직후부터 72시간 동안 시간경과에 비례하여 신생쥐의 대뇌 neurons의 수와 세포생존율을 유의하게 감소시켰다. 2) 저산소성-허혈은 저산소-허혈 유도 직후부터 72시간 동안 시간경과에 비례하여 신생쥐의 대뇌 astrocyte의수와 세포생존율을 다소 감소시켰다. 3) 저산소-허혈 유도 14일 후 neuron의 수와 세포 생존율 및 단백질합성은 대조군에 비하여 유의하게 감소하였으나 LDH는 매우 증가하였다. 4) 저산소-허혈 유도 직전 allopurinol 처리에 의하여 neuron의 수와 세포생존율 및 단백질합성은 유의하게 증가하였고 LDH치는 현저히 감소하였다. 5) 배양된 neuron에 대한 PKC 조사에 있어서 허혈 유도 10분에 현저한 PKC치의 증가를 보였으며, allopurinol의 전 처리는 허혈 유도에 의한 PKC치의 증가를 유의하게 감소시켰다. 결 론 : 저산소성-허혈은 신생쥐의 대뇌 신경세포에 독성효과를 나타냈으며 활성산소 제거제인 allopurinol은 세포수 및 세포생존률의 증가에 의한 신경세포의 손상보호를 나타내었고, 단백질합성 증가, LDH치 및 PKC치의 감소로 세포손상에 대한 효과적 방어도 관찰할 수 있었다.

• 한국의학물리학회지:의학물리
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• 제11권1호
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• pp.29-38
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• 2000

지금까지 각종 신경전달물질의 칼슘통로 억제 효과는 일반적으로 protein kinase 의 관여없이 G-protein mediated, membrane-delimited mechanism$^{1)}$ 으로 설명되어왔다. 그러나 최근들어 protein kinase C (PKC)의 활성화가 몇몇 신경전달물질에 의한 칼슘통로 억제효과를 야기하는 중요한 세포내 기전으로 보고되고 있다 그러므로 본 연구에서는 흰쥐 교감신경뉴론을 대상으로 하여 whole cell patch clamp technique을 사용하여 칼슘전류를 기록하고, 세포밖에 norepinephrine (NE)과 함께 PKC agonist 인 phorbol-12, 13-dibutyrate (PDBu)을 투여하면서 PDBu 전 처치로 인하여 NE 에 의한 칼슘전류 억제에 어떤 변화가 초래되는 지를 분석함으로써, 신경전달물질의 칼슘전류 억제효과시 PKC의 역할을 밝히고자 하였다. PDBu (500 nM) 처치는 칼슘전류의 크기를 증가시켰으며 이는 막전압 의존성을 보여 -10 mV ~ +10 mV 의 저분극 자극시 가장 크게 전류크기가 증가하였다. 또한 PDBu 처치는 tail current 의 deactivation을 느리게 하였다. PDBu 는 NE 에 의하여 활성화되는 pertussis toxin 예민성 G protein pathway를 통한 칼슘전류 억제를 감소시켰다. 비특이적인 protein kinase 길항제인 staurosporine (1 $\mu$M) 을 전처치 하고 PDBu를 투여하면 PDBu의 칼슘전류 크기 증가 효과가 소실되었으며 또한 NE에 의한 칼슘전류 억제를 해제하는 PDBu 의 조절효과도 소실되었다. 이상의 결과로부터 Protein Kinase C 가 활성되면 G protein을 경유하여 나타나는 칼슘전류 억제 효과가 소실된다고 결론지을 수 있다. Protein Kinase C 에 의하여 인산화되는 부위가 G-protein 인지 혹은 칼슘통로인 지에 관한 해답을 얻기 위하여는 추후 연구가 진행되어야 한다.

• 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