• KSBB Journal
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• v.21 no.6 s.101
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• pp.466-473
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• 2006

Impaired insulin secretion from pancreatic beta-cells in response to glucose is an important feature in the pathology of non-insulin-dependent diabetes mellitus (NIDDM). In the course of screening for useful insulin secretagogues, we have isolated and identified YHB-2017 (Genistein) as a insulin secretion potentiator from fermentation broths of our in-house microbial library. The insulinotropic activity of YHB-2017 in isolated rat pancreatic islets was exerted only at high concentration of glucose (8.3-16 mM) but not at low concentration of glucose (3.3-5.5 mM). Also, in perifusion study with isolated rat pancreatic islets, YHB-2017 stimulated insulin secretion in a time-dependent manner when YHB-2017 was added to KRB buffer containing 16 mM glucose. In the presence of $200\;{\mu}M$ diazoxide and 35 mM KCI, which stimulates maximum $Ca^{2+}$ influx independently of KATP channel, YHB-2017 enhanced KATP channel-independent insulin secretion at high concentration glucose (16 mM). To elucidate the mechanisms of the glucose-dependent potentiation effect of YHB-2017, pharmacologic inhibitors for protein kinase A, protein kinase C and calcium/calmodulin kinase II were pre-treated and then the potentiation effect of YHB-2017 on insulin secretion was investigated. Pre-treatment of H89 as a PKA inhibitor had a significant inhibitory effect on YHB-2017-induced potentiation effect. Furthermore, western immunoblotting analyses revealed that YHB-2017 increased phosphorylation of PKA substrates and cAMP response element-binding protein (CREB) under high concentration of glucose. These results demonstrated that the insulinotropic effect of YHB-2017 is mediated through PKA signal pathway and activated amplifying $K_{ATP}$ channel-independent insulin secretion pathway.

• The Korean Journal of Physiology and Pharmacology
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• v.12 no.5
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• pp.259-265
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• 2008

$[Ca^{2+}]_i$ transients by reverse mode of cardiac $Na^+/Ca^{2+}$ exchanger (NCX1) were recorded in fura-2 loaded BHK cells with stable expression of NCX1. Repeated stimulation of reverse NCX1 produced a long-lasting decrease of $Ca^{2+}$ transients ('rundown'). Rundown of NCX1 was independent of membrane $PIP_2$ depletion. Although the activation of protein kinase C (PKC) was observed during the $Ca^{2+}$ transients, neither a selective PKC inhibitor (calphostin C) nor a PKC activator (PMA) changed the degrees of rundown. By comparison, a non-specific PKC inhibitor, staurosporine (STS), reversed rundown in a dose-dependent and reversible manner. The action of STS was unaffected by pretreatment of the cells with calphostin C, PMA, or forskolin. Taken together, the results suggest that the stimulation of reverse NCX1 by STS is independent of PKC and/or PKA inhibition.

• BMB Reports
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• v.43 no.10
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• pp.704-709
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• 2010

The Swedish mutation (K595N/M596L) of amyloid precursor protein (APP-swe) has been known to increase abnormal cleavage of cellular APP by Beta-secretase (BACE), which causes tau protein hyperphosphorylation and early-onset Alzheimer's disease (AD). Here, we analyzed the effect of APP-swe in global gene expression using deep transcriptome sequencing technique. We found 283 genes were down-regulated and 348 genes were up-regulated in APP-swe expressing H4-swe cells compared to H4 wild-type cells from a total of approximately 74 million reads of 38 base pairs from each transcriptome. Two independent mechanisms such as kinase and phosphatase signaling cascades leading hyperphosphorylation of tau protein were regulated by the expression of APP-swe. Expressions of catalytic subunit as well as several regulatory subunits of protein phosphatases 2A were decreased. In contrast, expressions of tau-phosphorylating glycogen synthase kinase $3\beta$(GSK-3$\beta$), cyclin dependent kinase 5 (CDK5), and cAMP-dependent protein kinase A (PKA) catalytic subunit were increased. Moreover, the expression of AD-related Aquaporin 1 and presenilin 2 expression was regulated by APP-swe. Taken together, we propose that the expression of APP-swe modulates global gene expression directed to AD pathogenesis.

• The Korean Journal of Physiology and Pharmacology
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• v.16 no.5
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• pp.333-337
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• 2012

Gene expression of neuronal nitric oxide synthase (nNOS) changes in the hypothalamic paraventricular nucleus (PVN) depending on feeding conditions, which is decreased during food deprivation and restored by refeeding, and phosphorylated cAMP response element binding protein (pCREB) was suggested to play a role in its regulation. This study was conducted to examine if the fasting-induced down-regulation of the PVN-nNOS expression is restored by activation of cAMP-dependent protein kinase A (cAMP/PKA) pathway. Freely moving rats received intracerebroventricular (icv) injection of cAMP/PKA activator Sp-cAMP (40 nmol) or vehicle (sterilized saline) following 48 h of food deprivation. One hour after drug injections, rats were transcardially perfused with 4% paraformaldehyde, and the PVN tissues were processed for nNOS or pCREB immunohistochemistry. Sp-cAMP significantly increased not only nNOS but also pCREB immunoreactivities in the PVN of food deprived rats. Fastinginduced down-regulation of the PVN-nNOS was restored by 1 h after the icv Sp-cAMP. Results suggest that cAMP/PKA pathway may mediate the regulation of the PVN-nNOS expression depending on different feeding conditions.

• Nutrition Research and Practice
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• v.18 no.5
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• pp.587-601
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• 2024

BACKGROUND/OBJECTIVES: UV radiation is a major factor contributing to DNA damage in skin cells, including stem cells and mesenchymal stem cells, leading to the depletion of these crucial cells. This study examined whether a mixture of Indian gooseberry and barley sprout (IB) could inhibit UVB irradiation and 3-isobutyl-1-methylxanthine (IBMX)-induced photoaging and oxidative stress in the skin using HaCaT, Hs27, and B16F10 cells. MATERIALS/METHODS: The moisturizing-related factors, the collagen synthesis-related c-Jun N-terminal kinase (JNK)/c-Fos/c-Jun/matrix metalloproteinases (MMPs) pathway, and the melanogenesis-related cyclic adenosine monophosphate (cAMP)/protein kinase A (PKA)/cAMP-responsive binding protein (CREB)/melanocyte inducing transcription factor (MITF)/tyrosinase-related protein (TRP)/tyrosinase activation pathways were analyzed in vitro by an enzyme-linked immunosorbent assay, real-time polymerase chain reaction, and Western blot analysis. RESULTS: The IB complex increased the hyaluronic acid and sphingomyelin levels and the collagenase inhibitory activity, enhanced hydration-related factors, including collagen, hyaluronic acid synthase (HAS), elastin, long chain base subunit 1 (LCB1) (serine palmitoyltransferase; SPT), and delta 4-desaturase sphingolipid 1 (DEGS1), modulated the inflammatory cytokines levels, antioxidant enzyme activities and the NF-κB/MMPs/cyclooxygenase-2 (COX-2) pathway in UVB-irradiated HaCaT cells, and inhibited wrinkle formation by down-regulation of the JNK/c-Fos/c-Jun/MMP pathway and up-regulation of the transforming growth factor-𝛽 receptor I (TGF𝛽R1)/small mothers against decapentaplegic homolog (Smad3)/procollagen type I pathway in UVB-irradiated Hs27 cells. Moreover, the IB complex prevented melanin production by down-regulating the PKA/CREB/MITF/TRP-1/TRP-2 pathway in IBMX-induced B16F10 cells. CONCLUSION: These findings suggest that the IB complex has the potential to serve as a safeguard, shielding the skin from UVB radiation-induced photo-damage.

• Journal of Life Science
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• v.18 no.1
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• pp.114-119
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• 2008

The molecular machinery controlling cell cycle is centered around the regulation of the activity of maturation-promoting factor (MPF), a complex composed of a catalytic Cdc2 and the cyclinB regulatory subunit. Cdc2 kinase is inactivated by phosphorylation of inhibitory kinase, Wee1. It has been known that there are three different Wee1 kinases in the mammalian cell, Wee1A, Wee1B and Myt1. To investigate the regulatory mechanism of Wee1 kinases, the phosphorylation and degradation of Wee1A and Wee1B were checked in the Xenopus oocyte cell cycle. When Wee1 kinases were injected into frog oocyte, Wee1B was more stable than Wee1A. Wee1A and Wee1B kinase were phosphorylated by many kinases such as PKA and Akt. The roles of amino or carboxyl terminal in mouse Wee1A or Wee1B kinase were investigated using chimeric constructs. The degree of protein phosphorylation, degradation and cell cycle progression were different between chimeric constructs. The amino domain of Wee1A was implicated in the protein phosphorylation and degradation while amino domain of Wee1B and carboxyl domain of Wee1A were involved in the activity regulation. These results suggested that the domains of Wee1 kinase have different and significant roles in regulating the Wee1 kinases in the cell cycle progression.

• Journal of Life Science
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• v.32 no.5
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• pp.331-339
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• 2022

Melanin is a pigment produced by melanocytes to protect the skin from external stimuli, mainly ultraviolet (UV) rays. However, abnormal and excessive production of melanin causes hyperpigmentation disorders, such as freckles, age spots, and discoloration. Natural cosmeceuticals are a new trend for treating or preventing hyperpigmentation due to fewer side effects and biocompatibility. In this context, the current study focused on Cnidium japonicum, a halophyte with several uses in folk medicine, to evaluate its potential as a skin-whitening agent. The effect of C. japonicum extract (CJE) on melanin production was analyzed in melanogenesis-stimulated B16F10 melanoma cells. The results showed that CJE successfully inhibited the oxidation of tyrosine and L-DOPA by tyrosinase and subsequently decreased the production of the key enzymes responsible for melanin production: tyrosinase, tyrosinase-related protein-1, and protein-2. This effect was confirmed by decreased intracellular and extracellular melanin levels in B16F10 melanoma cells after CJE treatment. Further experiments to elucidate the action mechanism revealed that CJE treatment suppressed melanin production by inhibiting the activation of glycogen synthase kinase 3 β (GSKβ)/β-catenin and protein kinase A (PKA)/cAMP-response element binding protein (CREB) pathways, which are the upstream activators of melanogenesis. In conclusion, the present study suggests that C. japonicum is a potential natural source of bioactive substances for the development of novel cosmeceuticals that can act against hyperpigmentation.

• Clinical and Experimental Reproductive Medicine
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• v.22 no.2
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• pp.191-201
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• 1995

Transcriptional activation of the embryonic genome initiates at 2-cell stage in mouse embryo and is characterized by the synthesis of TRC which is restricted to 2-cell stage. To investigate the roles of various protein kinases on the embryonic gene activation, the effects of protein kinase inhibitors on in vitro development and protein synthetic profiles of the early mouse embryos were examinded. None of ${\alpna}-amanitin$ which is a mRNA synthetic inhibitor, H8 which is a PKA inhibitor, and H7 which is a PKC inhibitor, affected on first cleavage of mouse 1-cell embryos in vitro. However, all of these drugs inhibited the second cleavage. When the drugs were removed following treatment for 6 hours, H8 or H7 treatment showed little inhibition on subsequent development of 1-cell embryos to 2-cell stage or further. In contrast, ${\alpna}-amanitin$ irreversibly inhibited the development of 1-cell embryos to 2-cell stage following removal of the drug. Genistein, a TPK inhibitor, inhibited both the first cleavage of 1-cell embryos and the second cleavage of 2-cell embryos, suggesting that TPK activity may be important during the early cleavages. All of the above four drugs inhibited TRC synthesis as shown by the fluorographic analysis of $[^{35}S]-Met$ labeled protein profiles. When late 1-cell embryos were treated with H7 and analyzed synthetic patterns of $[^{35}S]-Met$ labeled protein, the quantitative differences of protein synthesis on SDS-PAGE appeared on 77 kD and 33 kD region at $32{\sim}38$ hours post hCG. From these studies, transcriptional activation of embryonic genome is not essenting to the mouse 1-cell embryos to develop to 2-cell stage. Hawever, TPK activity is reguisite for both the first cleavage and second cleavage. Similarly, both PKC and PKA activities are required for the second cleavage of mouse embryos, but not for the first cleavage.

• 한국균학회소식:학술대회논문집
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• 2014.10a
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• pp.43-43
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• 2014

The rice blast disease caused by of Magnaporthe oryzae is one of the most destructive diseases of rice. By the microarray analysis, we profiled expression changes of genes during conidiation and found out many putative genes that are up-regulated. Among those, we first selected MGG_06399 encoding a dual-specificity tyrosine-regulated protein kinase (DYRK), homologous to YAK1 in yeast. To investigate functional roles of MoYAK1, We made ${\Delta}Moyak1$ mutants by homology dependent gene replacement. The deletion mutant showed a remarkable reduction in conidiation and produced abnormally shaped conidia smaller than those of wild type. The conidia form ${\Delta}Moyak1$ were able to develop a germ tube, but failed to form apppressoria on a hydrophobic coverslip. The ${\Delta}Moyak1$ formed appressria on a hydrophobic cover slip when exogenous cAMP was induced, but the appressoria shape was abnormal. The ${\Delta}Moyak1$ also formed appressoria abberent in shape on onion epidermis and rice sheaths and failed to penetrate the surface of the plants. These data indicate that MoYAK1 is associated with cAMP/PKA pathway and important for conidiation, appressorial formation and pathogenic development in Magnaporthe oryzae. Detailed characterization of MoYAK1 will be presented.

• Journal of Acupuncture Research
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• v.25 no.2
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• pp.119-127
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• 2008

목적 : 골관절염치료에 빈용되는 유근피 약침액의 처치가 생쥐의 파골세포에 있어서 골재흡수의 저해에 미치는 영향을 알아보고자 하였다 방법 : 생쥐에게 유근피 약침액을 두개골 세포에 전, 후 처치하여 골재흡수에 대한 유근피 약침액의 억제 활성능을 검토하였다. 결론 : 염증성 cytokine 중 $IL-1{\beta}$ 유도인자인 PGE와 LPS처리로 $IL-1{\beta}$생성이 증가되었으나, 유근피 약침액 처치군은 이를 억제하였다. 유근피 약침액 전처리군에서도 $IL-1{\beta}$ 생성이 억제되었다. 유근피 약침액 처치군은 PGE2유발 $IL-1{\beta}$ 전사를 억제하였으며, PGE2 유발 $IL-1{\beta}$ 유도는 cAMP antagonist인 Rp-cAMP와 protein kinase A(PKA)저해제에 의해서도 억제되어 $IL-1{\beta}$ 발현에 cAMP, PKA 신호전달경로가 관여함을 시사하였다. 본 연구에서 유근피 약침액은 강한 항 관절염효과와 골재흡수 저해 활성이 있으며, 관절염 치료, 예방에 유의함을 밝힌 것으로 사료된다.