• Title/Summary/Keyword: Akt signaling

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The Mechanism of Whole Plant Extract of Viola verecunda on the Proliferation of Dermal Papilla Cells (콩제비꽃 전초 추출물의 모유두세포 증식 기전)

  • Kang, Jung-Il;Seo, Min Jeong;Choi, Youn Kyung;Shin, Su Young;Hwang, Yong;Goh, Jae duk;Yoo, Eun-Sook;Kim, Sang-Cheol;Kang, Hee-Kyoung
    • Korean Journal of Pharmacognosy
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    • v.52 no.1
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    • pp.34-40
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    • 2021
  • Proliferation and maintain of dermal papilla during progression of hair-cycle are crucial to the duration of anagen and regulated by diverse signaling pathway such as PI3K/Akt/Wnt/β-catenin pathway. In this study, we investigated the effects and mechanisms of Viola verecunda on dermal papilla cells. Treatment of dermal papilla cells with whole plant extract of V. verecunda resulted in cell proliferation, which was accompanied by up-regulation of cyclin D1, phospho (ser780)-pRB and cdc2 p34, and down-regulation of p27kip1. V. verecunda extract also promoted the levels of phospho (ser473)-Akt and phospho (ser780)-pRB in a time-dependent manner. Inhibition of PI3K/Akt by Wortmannin suppressed progression of cell-cycle, thereby attenuated the increases in proliferation of dermal papilla cells by V. verecunda extract. We further investigated Wnt/β-catenin pathway with respect to the effects of V. verecunda extract on the proliferation of dermal papilla cells. Treatment with V. verecunda extract results in up-regulation of Wnt/β-catenin proteins such as phospho (ser9)-GSKβ, phospho (ser552)-β-catenin and phospho (ser675)-β-catenin. In addition, Wortmannin abrogated V. verecunda extract mediated up-regulation of cdc2 p34 and down-regulation of p27kip1. These finding reveal that the proliferative effect of V. verecunda mediated by alteration of cell-cycle via activating PI3K/Akt/Wnt pathway in dermal papilla cells.

Puerarin pretreatment attenuates cardiomyocyte apoptosis induced by coronary microembolization in rats by activating the PI3K/Akt/GSK-3β signaling pathway

  • Chen, Zhi-Qing;Zhou, You;Huang, Jun-Wen;Chen, Feng;Zheng, Jing;Li, Hao-Liang;Li, Tao;Li, Lang
    • The Korean Journal of Physiology and Pharmacology
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    • v.25 no.2
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    • pp.147-157
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    • 2021
  • Coronary microembolization (CME) is associated with cardiomyocyte apoptosis and cardiac dysfunction. Puerarin confers protection against multiple cardiovascular diseases, but its effects and specific mechanisms on CME are not fully known. Hence, our study investigated whether puerarin pretreatment could alleviate cardiomyocyte apoptosis and improve cardiac function following CME. The molecular mechanism associated was also explored. A total of 48 Sprague-Dawley rats were randomly divided into CME, CME + Puerarin (CME + Pue), sham, and sham + Puerarin (sham + Pue) groups (with 12 rats per group). A CME model was established in CME and CME + Pue groups by injecting 42 ㎛ microspheres into the left ventricle of rats. Rats in the CME + Pue and sham + Pue groups were intraperitoneally injected with puerarin at 120 mg/kg daily for 7 days before operation. Cardiac function, myocardial histopathology, and cardiomyocyte apoptosis index were determined via cardiac ultrasound, hematoxylin-eosin (H&E) and hematoxylin-basic fuchsin-picric acid (HBFP) stainings, and TdT-mediated dUTP nick-end labeling (TUNEL) staining, respectively. Western blotting was used to measure protein expression related to the phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt)/glycogen synthase kinase-3β (GSK-3β) pathway. We found that, puerarin significantly ameliorated cardiac dysfunction after CME, attenuated myocardial infarct size, and reduced myocardial apoptotic index. Besides, puerarin inhibited cardiomyocyte apoptosis, as revealed by decreased Bax and cleaved caspase-3, and up-regulated Bcl-2 and PI3K/Akt/GSK-3β pathway related proteins. Collectively, puerarin can inhibit cardiomyocyte apoptosis and thus attenuate myocardial injury caused by CME. Mechanistically, these effects may be achieved through activation of the PI3K/Akt/GSK-3β pathway.

Protective Effects of Medicinal Herbal Mixture (HME) through Akt/FoxO3 Signal Regulation in Oxidative Damaged C2C12 Myotubes (C2C12 myotube의 산화적 손상에 대한 혼합 한약재 추출물(HME)의 Akt/FoxO3 신호 조절을 통한 보호 효과)

  • Kim, So Young;Choi, Moon-Yeol;Lee, Un Tak;Choo, Sung Tae;Kim, Mi Ryeo
    • The Korea Journal of Herbology
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    • v.37 no.4
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    • pp.31-38
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    • 2022
  • Objectives : In this study, we investigated the synergistic protective effects of medicinal herbal mixture (HME) including Mori Ramulus (MR), Acanthopanacis Cortex (AC), Eucommiae Cortex (EC), and Black soybean (BS) in C2C12 cells, mouse myoblasts. Methods : Effects of HME on cell viability of C2C12 myoblasts were monitored by MTT assay. Anti-atrophic activity of HME was determined in myoblasts and myotubes under oxidative stress by H2O2. C2C12 myoblasts were differentiated into myotubes in a medium containing 2% horse serum for 6 days. After that, we measured that expression of MyoD and myogenine, the myogenic regulatory factors, to identify the mechanism of inhibiting muscle atophy after HME treatment. In addition, suppression of phosphorylation of Akt, FoxO3a and MARF-1, transcription factors of degradation proteins were analyzed via western blotting. Results : As a result of MTT, HME there was no show cytotoxicity up to a concentration of 1 mg/ml. The cytoprotective effects on oxidative stressed myoblast and myotube was better in HME extract than those of MR, AC, EU, and BS, respectively. HME treatment in Myotube induced by oxidative stress after H2O2 treatment increased Myo D, Myogenine activation, and Akt, FoxO3a phosphorylation and decreased expression of MuRF-1. As the results, HME has synergistic effects on protection against proteolysis of C2C12 myotubes through activation of the Akt signaling pathway under oxidative stress. Conclusions : These results suggest that HME may also be useful as a preventing and treating material for skeletal muscle atrophy caused by age-related diseases.

Changes in expression of insulin signaling pathway genes by dietary fat source in growing-finishing pigs

  • Kim, Seung-Chang;Jang, Hong-Chul;Lee, Sung-Dae;Jung, Hyun-Jung;Park, Jun-Cheol;Lee, Seung-Hwan;Kim, Tae-Hun;Choi, Bong-Hwan
    • Journal of Animal Science and Technology
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    • v.56 no.4
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    • pp.12.1-12.7
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    • 2014
  • This study investigated changes in gene expression by dietary fat source, i.e., beef tallow, soybean oil, olive oil, and coconut oil (each 3% in feed), in both male and female growing-finishing pigs. Real-time PCR was conducted on seven genes (insulin receptor; INSR, insulin receptor substrate; IRS, phosphatidylinositol (3,4,5)-triphosphate; PIP3, 3-phosphoinositide-dependent protein kinase-1; PDK1, protein kinase B; Akt, forkhead box protein O1; FOXO1 and cGMP-inhibited 3', 5'-cyclic phosphodiesterase; PDE3) located upstream of the insulin signaling pathway in the longissimus dorsi muscle (LM) of pigs. The INSR, IRS, PIP3, and PDE3 genes showed significantly differential expression in barrow pigs. Expression of the PIP3 and FOXO1 genes was significantly different among the four dietary groups in gilt pigs. In particular, the PIP3 gene showed the opposite expression pattern between barrow and gilt pigs. These results show that dietary fat source affected patterns of gene expression according to animal gender. Further, the results indicate that the type of dietary fat affects insulin signaling-related gene expression in the LM of pigs. These results can be applied to livestock production by promoting the use of discriminatory feed supplies.

Pear pomace ethanol extract improves insulin resistance through enhancement of insulin signaling pathway without lipid accumulation

  • You, Mi-Kyoung;Kim, Hwa-Jin;Rhyu, Jin;Kim, Hyeon-A
    • Nutrition Research and Practice
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    • v.11 no.3
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    • pp.198-205
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    • 2017
  • BACKGROUND/OBJECTIVES: The anti-diabetic activity of pear through inhibition of ${\alpha}-glucosidase$ has been demonstrated. However, little has been reported about the effect of pear on insulin signaling pathway in obesity. The aims of this study are to establish pear pomace 50% ethanol extract (PPE)-induced improvement of insulin sensitivity and characterize its action mechanism in 3T3-L1 cells and high-fat diet (HFD)-fed C57BL/6 mice. MATERIALS/METHODS: Lipid accumulation, monocyte chemoattractant protein-1 (MCP-1) secretion and glucose uptake were measure in 3T3-L1 cells. Mice were fed HFD (60% kcal from fat) and orally ingested PPE once daily for 8 weeks and body weight, homeostasis model assessment of insulin resistance (HOMA-IR), and serum lipids were measured. The expression of proteins involved in insulin signaling pathway was evaluated by western blot assay in 3T3-L1 cells and adipose tissue of mice. RESULTS: In 3T3-L1 cells, without affecting cell viability and lipid accumulation, PPE inhibited MCP-1 secretion, improved glucose uptake, and increased protein expression of phosphorylated insulin receptor substrate 1 [p-IRS-1, ($Tyr^{632})$)], p-Akt, and glucose transporter type 4 (GLUT4). Additionally, in HFD-fed mice, PPE reduced body weight, HOMA-IR, and serum lipids including triglyceride and LDL-cholesterol. Furthermore, in adipose tissue, PPE up-regulated GLUT4 expression and expression ratio of p-IRS-1 ($Tyr^{632})/IRS$, whereas, down-regulated p-IRS-1 ($Ser^{307})/IRS$. CONCLUSIONS: Our results collectively show that PPE improves glucose uptake in 3T3-L1 cells and insulin sensitivity in mice fed a HFD through stimulation of the insulin signaling pathway. Furthermore, PPE-induced improvement of insulin sensitivity was not accompanied with lipid accumulation.

Immunostimulatory Activities of Polysaccharides from Liquid Culture of Pine-Mushroom Tricholoma matsutake

  • Kim, Joo-Young;Byeon, Se-Eun;Lee, Yong-Gyu;Lee, Ji-Yeon;Park, Jong-Sun;Hong, Eock-Ki;Cho, Jae-Youl
    • Journal of Microbiology and Biotechnology
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    • v.18 no.1
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    • pp.95-103
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    • 2008
  • Mushrooms are regarded as one of the well-known foods and biopharmaceutical materials with a great deal of interest. Polysaccharide ${\beta}$-glucan is the major component of mushrooms that displays various biological activities such as antidiabetic, anticancer, and antihyperlipidemic effects. In this study, we compared the immunostimulatory potency of polysaccharide fractions, prepared from liquid culture of pine-mushroom Tricholoma matsutake, with a potent immunogen lipopolysaccharide (LPS), and their molecular mechanisms on the functional activation of macrophages. We found that fraction II (TMF-II) was able to comparably upregulate or highly enhance the phenotypic functions of macrophages such NO production and cytokine (IL-$1{\beta}$, IL-6, IL-12, and TNF-${\alpha}$) expression, to LPS. TMF-II triggered the phosphorylation of $I{\kappa}B{\alpha}$, a critical step for NF-${\kappa}B$ activation and translocation. Of the upstream signaling enzymes tested, Src and Akt were thought to be the responsible upstream signaling components in induction of NO production, although TMF-II strongly upregulated the phosphorylation of all MAPK pathways. Therefore, our data suggest that T. matsutake-derived ${\beta}$-glucan may exert its immunostimulating activities with similar potency to LPS via activation of multiple signaling pathways linked to NF-${\kappa}B$ activation.

Conditioning-induced cardioprotection: Aging as a confounding factor

  • Randhawa, Puneet Kaur;Bali, Anjana;Virdi, Jasleen Kaur;Jaggi, Amteshwar Singh
    • The Korean Journal of Physiology and Pharmacology
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    • v.22 no.5
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    • pp.467-479
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    • 2018
  • The aging process induces a plethora of changes in the body including alterations in hormonal regulation and metabolism in various organs including the heart. Aging is associated with marked increase in the vulnerability of the heart to ischemia-reperfusion injury. Furthermore, it significantly hampers the development of adaptive response to various forms of conditioning stimuli (pre/post/remote conditioning). Aging significantly impairs the activation of signaling pathways that mediate preconditioning-induced cardioprotection. It possibly impairs the uptake and release of adenosine, decreases the number of adenosine transporter sites and down-regulates the transcription of adenosine receptors in the myocardium to attenuate adenosine-mediated cardioprotection. Furthermore, aging decreases the expression of peroxisome proliferator-activated receptor gamma co-activator 1-alpha ($PGC-1{\alpha}$) and subsequent transcription of catalase enzyme which subsequently increases the oxidative stress and decreases the responsiveness to preconditioning stimuli in the senescent diabetic hearts. In addition, in the aged rat hearts, the conditioning stimulus fails to phosphorylate Akt kinase that is required for mediating cardioprotective signaling in the heart. Moreover, aging increases the concentration of $Na^+$ and $K^+$, connexin expression and caveolin abundance in the myocardium and increases the susceptibility to ischemia-reperfusion injury. In addition, aging also reduces the responsiveness to conditioning stimuli possibly due to reduced kinase signaling and reduced STAT-3 phosphorylation. However, aging is associated with an increase in MKP-1 phosphorylation, which dephosphorylates (deactivates) mitogen activated protein kinase that is involved in cardioprotective signaling. The present review describes aging as one of the major confounding factors in attenuating remote ischemic preconditioning-induced cardioprotection along with the possible mechanisms.

Prediction the efficacy and mechanism of action of Daehwangmokdanpitang to treat psoriasis based on network pharmacology (네트워크 약리학 기반 대황목단피탕(大黃牧丹皮湯)의 건선 조절 효능 및 작용 기전 예측)

  • Bitna Kweon;Dong-Uk Kim;Gabsik Yang; Il-Joo Jo
    • The Korea Journal of Herbology
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    • v.38 no.6
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    • pp.73-91
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    • 2023
  • Objectives : This study used a network pharmacology approach to elucidate the efficacy and molecular mechanisms of Daehwangmokdanpitang (DHMDPT) on Psoriasis. Methods : Using OASIS databases and PubChem database, compounds of DHMDPT and their target genes were collected. The putative target genes of DHMDPT and known target genes of psoriasis were compared and found the correlation. Then, the network was constructed using Cytoscape 3.10.1. The key target genes were screened by Analyzer network and their functional enrichment analysis was conducted based on the Gene Ontology (GO) enrichment analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) Pathways to predict the mechanisms. Results : The result showed that total 30 compounds and 439 related genes were gathered from DHMDPT. 264 genes were interacted with psoriasis gene set, suggesting that the effects of DHMDPT are closely related to psoriasis. Based on GO enrichment analysis and KEGG pathways, 'Binding', 'Cytokine Activity', 'Receptor Ligand Activity' 'HIF-1 signaling pathway', 'IL-17 signaling pathway', 'Toll-like receptor signaling pathway', and 'TNF signaling pathway' were predicted as functional pathways of 16 key target genes of DHMDPT on psoriasis. Among the target genes, IL6, IL1B, TNF, AKT1 showed high correlation with the results of KEGG pathways. Additionally, Emodin, Acetovanillone, Gallic acid, and Ferulic acid showed a high relevance with key genes and their mechanisms. Conclusion : Through a network pharmacological method, DHMDPT was predicted to have high relevance with psoriasis. This study could be used as a basis for studying therapeutic effects of DHMDPT on psoriasis.

Induction of Apoptosis and Inhibition of Growth in Human Gastric Cancer by Piperine (Piperine에 의한 위암세포 AGS 증식 억제와 Apoptosis 유도)

  • Shin, Seong-Ah;Lee, Hae-Nim;Choo, Gang-Sik;Kim, So-Jung;Kim, Hyeong-Jin;Park, Young-Seok;Park, Byung-Kwon;Kim, Byeong-Soo;Kim, Sang-Ki;Lee, Hu-Jang;Jung, Ji-Youn
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.45 no.11
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    • pp.1589-1594
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    • 2016
  • Piperine [(E,E)-5-(3,4-methtylenedioxyphenyl)-2,4-pentadienolypiperidide] is a principal of Piperaceae, including Piper nigrum L. and Piper longum Linn., which has been used as a spice and traditional medicine. In this study, we investigated whether or not piperine has anti-cancer effects on AGS human gastric cancer cells. The results demonstrated that piperine not only inhibited proliferation using MTT assay but also induced apoptotic bodies using DAPI assay in a dose-dependent manner in response to piperine. Expression levels of p53, Bax (pro-apoptotic), cleaved caspase-9, and cleaved-PARP increased, whereas expression levels of Bcl-2, XIAP (anti-apoptotic), and Akt decreased in a dose-dependent manner compared with the control by western blotting analysis. To identify the connection between phospo-Akt and Bcl-2 family in response to piperine, LY249002 (Akt inhibitor) was treated with piperine ($150{\mu}M$). The results were shown that expression of phospo-Akt was reduced whereas expression of Bax and cleaved-PARP increased in a dose-dependent manner. These results indicate that piperine induced apoptosis in AGS cells and may serve as a chemopreventive or therapeutic agent for human gastric cancer.

The Stimulatory Effect of Essential Fatty Acids on Glucose Uptake Involves Both Akt and AMPK Activation in C2C12 Skeletal Muscle Cells

  • Park, So Yeon;Kim, Min Hye;Ahn, Joung Hoon;Lee, Su Jin;Lee, Jong Ho;Eum, Won Sik;Choi, Soo Young;Kwon, Hyeok Yil
    • The Korean Journal of Physiology and Pharmacology
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    • v.18 no.3
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    • pp.255-261
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    • 2014
  • Essential fatty acid (EFA) is known to be required for the body to function normally and healthily. However, the effect of EFA on glucose uptake in skeletal muscle has not yet been fully investigated. In this study, we examined the effect of two EFAs, linoleic acid (LA) and ${\alpha}$-linolenic acid (ALA), on glucose uptake of C2C12 skeletal muscle cells and investigated the mechanism underlying the stimulatory effect of polyunsaturated EFAs in comparison with monounsaturated oleic acid (OA). In palmitic acid (PA)-induced insulin resistant cells, the co-treatment of EFAs and OA with PA almost restored the PA-induced decrease in the basal and insulin-stimulated 2-NBDG (fluorescent D-glucose analogue) uptake, respectively. Two EFAs and OA significantly protected PA-induced suppression of insulin signaling, respectively, which was confirmed by the increased levels of Akt phosphorylation and serine/threonine kinases ($PKC{\theta}$ and JNK) dephosphorylation in the western blot analysis. In PA-untreated, control cells, the treatment of $500{\mu}M$ EFA significantly stimulated 2-NBDG uptake, whereas OA did not. Phosphorylation of AMP-activated protein kinase (AMPK) and one of its downstream molecules, acetyl-CoA carboxylase (ACC) was markedly induced by EFA, but not OA. In addition, EFA-stimulated 2-NBDG uptake was significantly inhibited by the pre-treatment of a specific AMPK inhibitor, adenine 9-${\beta}$-D-arabinofuranoside (araA). These data suggest that the restoration of suppressed insulin signaling at PA-induced insulin resistant condition and AMPK activation are involved at least in the stimulatory effect of EFA on glucose uptake in C2C12 skeletal muscle cells.