• Biomedical Science Letters
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• v.14 no.2
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• pp.69-76
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• 2008

${\gamma}$-aminobutyric acid (GABA) is the major inhibitory neurotransmitter in the central nervous system, and its actions are mediated by subtypes of GABA receptors named as $GABA_A$, $GABA_B,\;and\;GABA_C,\;GABA_A$, receptor consisting of ${\alpha},\;{\beta},\;{\gamma}\;and\;{\delta}$ subunits is a heterooligomeric ligand-gated chloride channel. This study was performed to investigate regulation of $GABA_A$ receptor by protein kinase C(PKC). Ion currents were recorded using gramicidine-perforated patch and whole cell patch clamp. mRNA encoding the subunits of PKC expressed in major pelvic ganglion (MPG) neurons was detected by using RT-PCR. The GABA-induced inward current was increased by PKC activators and decreased by PKC inhibitors, respectively. These effects were not associated with intracellular $Ca^{2+}$ and GAG (1-oleoyl-2-acetyl-sn-glycerol), a membrane permeable diacylglycerol (DAG) analogue. These results mean that the subfamily of PKC participating in activation of $GABA_A$ receptor would be an atypical PKC (aPKC). Among theses, ${\xi}$ isoform of aPKC was detected by RT-PCR. Taking together, we suggest that excitable $GABA_A$ receptor in sympathetic MPG neuron seemed to be regulated by aPKC, particular in ${\xi}$ isoform. The regulatory roles of PKC on excitatory $GABA_A$ receptors in sympathetic neurons of MPG may be an important factor to control the functional activity of various pelvic organs such as bowel movement, micturition and erection.

• Korean Journal of Clinical Laboratory Science
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• v.55 no.3
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• pp.184-194
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• 2023

In this study, we investigated whether p-anisaldehyde (PAA), the main component of essential oils derived from anise seeds, influences the differentiation of mouse C2C12 myoblasts. Cells were induced to differentiate over 5 days using a differentiation medium with or without PAA (50 or 200 mg/mL). Myotube length and diameter were measured, and the expressions of myogenic markers (myoblast determination protein 1, myogenin, myocyte enhancer factor 2, muscle creatine kinase, and myosin heavy chain) and atrophy-related genes (atrogin-1 and muscle ring finger-1 [MuRF-1]) were assessed by quantitative real-time polymerase chain reaction. Additionally, protein kinase B (Akt) phosphorylation was monitored by western blotting. PAA significantly induced the formation of smaller and thinner myotubes and reduced myogenic marker expression. Furthermore, PAA increased the expressions of atrogin-1 and MuRF-1 and simultaneously reduced Akt phosphorylation. Our findings indicate that PAA inhibits the myogenic differentiation of C2C12 cells by reducing the phosphorylation and activation of Akt.

• Journal of Photoscience
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• v.9 no.2
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• pp.25-28
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• 2002

The chicken pineal gland has been used for studies on the circadian clock, because it retains an intracellular phototransduction pathway regulating the phase of the intrinsic clock oscillator. Previously, we identified chicken clock genes expressed in the gland (cPer2, cPer3, cBmal1, cBmal2, cCry1, cCry2, and cClock), and showed that a cBMALl/2-cCLOCK heteromer acts as a regulator transactivating cPer2 gene through the CACGTG E-box element found in its promoter. Notably, mRNA expression of cPer2 gene is up-regulated by light as well as is driven by the circadian clock, implying that light-dependent clock resetting may involve the up-regulation of cPer2 gene. To explore the mechanism of light-dependent gene expression unidentified in animals, we first focused on pinopsin gene whose mRNA level is also up-regulated by light. A pinopsin promoter was isolated and analyzed by transcriptional assays using cultured chicken pineal cells, resulting in identification of an 18-bp light-responsive element that includes a CACGTG E-box sequence. We also investigated a role of mitogen-activated protein kinase (MAPK) in the clock resetting, especially in the E-box-dependent transcriptional regulation, because MAPK is phospholylated (activated) in a circadian manner and is rapidly dephosphorylated by light in the gland. Both pulldown analysis and kinase assay revealed that MAPK directly associates with BMAL1 to phosphorylate it at several Ser/Thr residues. Transcriptional analyses implied that the MAPK-mediated phosphorylation may negatively regulate the BMAL-CLOCK-dependent transactivation through the E-box. These results suggest that the CACGTG E-box serves not only as a clock-controlled element but also as a light-responsive element.

• Biomolecules & Therapeutics
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• v.21 no.6
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• pp.435-441
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• 2013

Emodin, a naturally occurring anthraquinone derivative isolated from Polygoni cuspidati radix, has several beneficial pharmacologic effects, which include anti-cancer, anti-diabetic, and anti-inflammatory activities. In this study, the authors examined the effect of emodin on the production of proinflammatory cytokines, such as, tumor necrosis factor (TNF)-${\alpha}$ and interleukin (IL)-6, in mouse bone marrow-derived mast cells (BMMCs) stimulated with phorbol 12-myristate 13-acetate (PMA) plus the calcium ionophore A23187. To investigate the mechanism responsible for the regulation of pro-inflammatory cytokine production by emodin, the authors assessed its effects on the activations of transcriptional factor nuclear factor-${\kappa}B$ (NF-${\kappa}B$) and mitogen-activated protein kinases (MAPKs). Emodin attenuated the nuclear translocation of (NF)-${\kappa}B$ p65 and its DNA-binding activity by reducing the phosphorylation and degradation of $I{\kappa}B{\alpha}$ and the phosphorylation of $I{\kappa}B$ kinase B (IKK). Furthermore, emodin dose-dependently attenuated the phosphorylations of MAPKs, such as, extracellular signal-regulated kinase 1/2 (ERK1/2), p38 MAP kinase, and the stress-activated protein kinases (SAPK)/c-Jun-N-terminal kinase (JNK). Taken together, the findings of this study suggest that the anti-inflammatory effects of emodin on PMA plus A23187-stimulated BMMCs are mediated via the inhibition of NF-${\kappa}B$ activation and of the MAPK pathway.

• Korean Journal of Environmental Biology
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• v.21 no.1
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• pp.52-55
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• 2003

There is considerable evidence that ionizing radiation (IR) mediates checkpoint control, repair and cell death. In this study, we have used a high density microarray hybridization approach to characterize the transcriptional response of human breast carcinoma MCF-7 cell line to ${\gamma}$-radiation, such as 4 Gy 4 hr, 8 Gy 4 hr, and 8 Gy 12 hr. We found that exposure to ${\gamma}$-ray alters by at least a $log_2$ factor of 1.0 the expression of 115 known genes. Of the 66 genes affected by ${\gamma}$-radiation, 49 are down-regulated. In our results, the cellular response to irradiation includes induction of the c-jun and EGR1 early response genes. The present work has examined potential cytoplasmic signaling cascades that transduce IR-induced signals to the nucleus. 40S ribosomal protein s6 kinase modulates the activities of the mitogen activated protein kinase (MAPK) and c-Jun $NH_2$-terminal kinase (JNK1) cascades in human monocytic leukemia (U937/pREP4) cells. 14-3-3 family members are dimeric phosphoserine -binding proteins that participate in signal transduction and checkpoint control pathways.

• Biomolecules & Therapeutics
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• v.29 no.1
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• pp.41-51
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• 2021

Src family kinases (SFKs), an important group of non-receptor tyrosine kinases, are suggested to be excessively activated during various types of tissue fibrosis. The present study investigated the effect of KF-1607, an orally active and a newly synthesized Src kinase inhibitor (SKI) with proposed low toxicity, in preventing the progression of renal interstitial fibrosis. Unilateral ureteral obstruction (UUO) surgery was performed in 6-week-old male C57BL/6 mice to induce renal interstitial fibrosis. Either KF-1607 (30 mg/kg, oral gavage) or PP2 (2 mg/kg, intraperitoneal injection), a common experimental SKI, was administered to mice for seven days, started one day prior to surgery. UUO injury-induced SFK expression, including Src, Fyn, and Lyn kinase. SFK inhibition by KF-1607 prevented the progression of tubular injury in UUO mice, as indicated by decreases in albuminuria, urinary KIM-1 excretion, and kidney NGAL protein expression. Renal tubulointerstitial fibrosis was attenuated in response to KF-1607, as shown by decreases in α-SMA, collagen I and IV protein expression, along with reduced Masson's trichrome and collagen-I staining in kidneys. KF-1607 also inhibited inflammation in the UUO kidney, as exhibited by reductions in F4/80 positive-staining and protein expression of p-NFκB and ICAM. Importantly, the observed effects of KF-1607 were similar to those of PP2. A new pan Src kinase inhibitor, KF-1607, is a potential pharmaceutical agent to prevent the progression of renal interstitial fibrosis.

• BMB Reports
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• v.30 no.3
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• pp.194-199
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• 1997

Previous studies have shown that the HD3 human enterocytic differentiated colon carcinoma cell lines having low $PKC{\beta}$ activity did not respond to diacylglycerol and basic FGF by growth and by activation of pp57 MAP kinase, but undifferentiated cell lines exhibiting high $PKC{\beta}$ activity did. To confirm a role of $PKC{\beta}$ in colonocyte mitogenesis, derivatives of HD3 cell line that stably overexpress a full-length of cDNA encoding the ${\beta}_1$ isoform of human PKC were generated. The abundance and activity of $PKC{\beta}$ in two of the these cell lines, PKC3 and PKC8 were much higher than those in the C1 control cell line that carries the vector lacking the $PKC{\beta}_1\;cDNA$ insert. Following exposure to diacylglycerol or basic FGF, proliferation of PKC3 and PKC8 cells increased about 50%; but this effect was not seen with the control C1 cells. Also, in contrast to the control cells, the $PKC{\beta}_1-overproducing$ cells displayed activation of pp57 MAP kinase when treated with diacylglycerol and basic FGF as undifferentiated cell lines did. These results provide direct evidence that $PKC{\beta}_1$ which plays a key role in mitogenic responses of colon carcinoma cells to diacylglycerol and basic FGF is down-regulated in enterocytic differentiation of colon cells.

• Journal of Ginseng Research
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• v.39 no.4
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• pp.354-364
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• 2015

Background: Intracellular $Ca^{2+}$($[Ca^{2+}]_i$) is a platelet aggregation-inducing molecule. Therefore, understanding the inhibitory mechanism of $[Ca^{2+}]_i$mobilization is very important to evaluate the antiplatelet effect of a substance. This study was carried out to understand the $Ca^{2+}$-antagonistic effect of total saponin from Korean Red Ginseng (KRG-TS). Methods: We investigated the $Ca^{2+}$-antagonistic effect of KRG-TS on cyclic nucleotides-associated phosphorylation of inositol 1,4,5-trisphosphate receptor type I ($IP_3RI$) and cyclic adenosine monophosphate (cAMP)-dependent protein kinase (PKA) in thrombin (0.05 U/mL)-stimulated human platelet aggregation. Results: The inhibition of $[Ca^{2+}]_i$ mobilization by KRG-TS was increased by a PKA inhibitor (Rp-8-BrcAMPS), which was more stronger than the inhibition by a cyclic guanosine monophosphate (cGMP)- dependent protein kinase (PKG) inhibitor (Rp-8-Br-cGMPS). In addition, Rp-8-Br-cAMPS inhibited phosphorylation of PKA catalytic subunit (PKAc) ($Thr^{197}$) by KRG-TS. The phosphorylation of $IP_3RI$ ($Ser^{1756}$) by KRG-TS was very strongly inhibited by Rp-8-Br-cAMPS compared with that by Rp-8-BrcGMPS. These results suggest that the inhibitory effect of $[Ca^{2+}]_i$ mobilization by KRG-TS is more strongly dependent on a cAMP/PKA pathway than a cGMP/PKG pathway. KRG-TS also inhibited the release of adenosine triphosphate and serotonin. In addition, only G-Rg3 of protopanaxadiol in KRG-TS inhibited thrombin-induced platelet aggregation. Conclusion: These results strongly indicate that KRG-TS is a potent beneficial compound that inhibits $[Ca^{2+}]_i$ mobilization in thrombin-platelet interactions, which may result in the prevention of platelet aggregation-mediated thrombotic disease.

• Animal cells and systems
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• v.3 no.4
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• pp.385-391
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• 1999

Changes in the levels of prostaglandian F$_{2a}$ (PGF$_{2a}$) and E$_2$ (PGE$_2$) in culture medium during in vitro ovulation of Rana dybowskii follicles were examined. The ovulation was induced by frog pituitary homogenate (FPH) or TPA (12-O-tetradecanoylphorbol-13-acetate, a protein kinase activator) and the levels of PGs were measured by radioimmunoassay. When the ovarian follicles were cultured, only a few oocytes were ovulated by 12 h, but half of them were ovulated by 24 h in response to FPH, whereas around 30% of oocytes were ovulated by 12 h and maximum ovulation (around 50%) occurred by 24 h in response to TPA. Without any stimulation (control), no ovulation occurred. TPA elevated the level of PGF$_{2a}$ to high levels when compared to control (basal levels), but the increase by FPH was less evident. Likewise, the levels of PGE$_2$ increased markedly in response to TPA, but rather decreased by FPH treatment. Interestingly, PGF$_{2a}$ induced ovulation but PGE$_2$ suppressed FPH- or PGF$_{2a}$-induced oocyte ovulation. Basal levels of PGs Increased steadily during culture. When theca/epithelium (THEP) layer and granulosa cell-enclosed oocytes (GCEOs) were separated by microdissection and cultured independently, higher levels of both PGs were secreted by THEP than by GCEOS. Synthesis of PGs by follicle or follicular components was strongly suppressed by exogenous cAMP or indomethacin. These results suggest that: 1) PGF$_{2a}$ plays an important role in Rana ovulation, 2) protein kinase C is involved in PGs production, and 3) thecal epithelium layer is responsible for the PGs production in Rana.

• CELLMED
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• v.13 no.6
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• pp.7.1-7.6
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• 2023

Raphanus sativus L. has been reported to have anti-inflammatory and anti-tumor activity. However, the anti-inflammatory effect and mechanism of action of the Raphanus sativus L. seeds (RSS) with or without oil are still unknown. This study was undertaken to investigate the in-vitro anti-inflammatory effect with or without oil in the RSS on RAW 264.7 cells stimulated by lipopolysaccharide (LPS). Results showed the suppressed LPS-induced secretion of pro-inflammatory mediators such as nitric oxide (NO), inflammatory cytokine (IL-6, TNF-α). Additionally, a decrease in protein expression of iNOS was observed, but nuclear translocation of NF-κB p65 was not inhibited. To elucidate the underlying mechanism of the anti-inflammatory effect of RSS, the involvement of mitogen-activated protein kinase (MAPK) signaling pathways was examined. We also found that RSS blocked LPS-induced phosphorylation of c-Jun N-terminal kinase/stress-activated protein kinase (JNK) signaling but did not affect the phosphorylation of p38 MAPK and extracellular signal-regulated kinase (ERK) 1/2. These results suggest that RSS may have potential as an anti-inflammatory agent through the inhibition of LPS-induced inflammatory cytokine production via regulation of the JNK pathway.