1
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Pyo JH, Jeon HJ, Park JS, Lee JS, Chung HY, Yoo MA. Drosophila PEBP1 inhibits intestinal stem cell aging via suppression of ERK pathway. Oncotarget 2018; 9:17980-17993. [PMID: 29719584 PMCID: PMC5915051 DOI: 10.18632/oncotarget.24834] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Accepted: 03/06/2018] [Indexed: 12/19/2022] Open
Abstract
The intestine is a high cellular turnover tissue largely dependent on the regenerative function of stem cell throughout life, and a signaling center for the health and viability of organisms. Therefore, better understanding of the mechanisms underlying the regulation of intestinal stem cell (ISC) regenerative potential is essential for the possible intervention of aging process and age-related diseases. Drosophila midgut is a well-established model system for studying the mechanisms underlying ISC regenerative potential during aging. Here, we report the requirement of Drosophila phosphatidylethanolamine binding protein 1 (PEBP1) in ISC regenerative potential. We showed that PEBP1 was strongly expressed in enterocytes (ECs) of guts and its decrease with age and oxidative stress. Furthermore, the downregulation of PEBP1 in ECs accelerates ISC aging, as evidenced by ISC hyper-proliferation, γH2AX accumulation, and centrosome amplification, and intestinal hyperplasia. The decrease in PEBP1 expression was associated with increased extracellular signal-regulated kinase (ERK) activity in ECs. All these phenotypes by EC-specific depletion of PEBP1 were rescued by the concomitant inhibition of ERK signaling. Our findings evidence that the age-related downregulation of PEBP1 in ECs is a novel cause accelerating ISC aging and that PEBP1 is an EC-intrinsic suppressor of epidermal growth factor receptor (EGFR)/ERK signaling. Our study provides molecular insights into the tight regulation of EGFR/ERK signaling in niches for stem cell regenerative potential.
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Affiliation(s)
- Jung-Hoon Pyo
- Department of Molecular Biology, Pusan National University, Busan, Republic of Korea.,Institute of Systems Biology (ISB), Pusan National University, Busan, Republic of Korea.,Molecular Inflammation Research Center for Aging Intervention (MRCA), College of Pharmacy, Pusan National University, Busan, Republic of Korea
| | - Ho-Jun Jeon
- Department of Molecular Biology, Pusan National University, Busan, Republic of Korea
| | - Joung-Sun Park
- Department of Molecular Biology, Pusan National University, Busan, Republic of Korea.,Institute of Systems Biology (ISB), Pusan National University, Busan, Republic of Korea
| | - Jae-Sun Lee
- Department of Molecular Medicine and Hypoxia-Related Disease Research Center, Inha University College of Medicine, Incheon, Republic of Korea
| | - Hae-Young Chung
- Molecular Inflammation Research Center for Aging Intervention (MRCA), College of Pharmacy, Pusan National University, Busan, Republic of Korea
| | - Mi-Ae Yoo
- Department of Molecular Biology, Pusan National University, Busan, Republic of Korea.,Institute of Systems Biology (ISB), Pusan National University, Busan, Republic of Korea
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2
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Park JS, Jeon HJ, Pyo JH, Kim YS, Yoo MA. Deficiency in DNA damage response of enterocytes accelerates intestinal stem cell aging in Drosophila. Aging (Albany NY) 2018; 10:322-338. [PMID: 29514136 PMCID: PMC5892683 DOI: 10.18632/aging.101390] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Accepted: 02/23/2018] [Indexed: 09/29/2023]
Abstract
Stem cell dysfunction is closely linked to tissue and organismal aging and age-related diseases, and heavily influenced by the niche cells' environment. The DNA damage response (DDR) is a key pathway for tissue degeneration and organismal aging; however, the precise protective role of DDR in stem cell/niche aging is unclear. The Drosophila midgut is an excellent model to study the biology of stem cell/niche aging because of its easy genetic manipulation and its short lifespan. Here, we showed that deficiency of DDR in Drosophila enterocytes (ECs) accelerates intestinal stem cell (ISC) aging. We generated flies with knockdown of Mre11, Rad50, Nbs1, ATM, ATR, Chk1, and Chk2, which decrease the DDR system in ECs. EC-specific DDR depletion induced EC death, accelerated the aging of ISCs, as evidenced by ISC hyperproliferation, DNA damage accumulation, and increased centrosome amplification, and affected the adult fly's survival. Our data indicated a distinct effect of DDR depletion in stem or niche cells on tissue-resident stem cell proliferation. Our findings provide evidence of the essential role of DDR in protecting EC against ISC aging, thus providing a better understanding of the molecular mechanisms of stem cell/niche aging.
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Affiliation(s)
- Joung-Sun Park
- Department of Molecular Biology, Pusan National University, Busan 46241, Republic of Korea
- Equal contribution
| | - Ho-Jun Jeon
- Department of Molecular Biology, Pusan National University, Busan 46241, Republic of Korea
- Equal contribution
| | - Jung-Hoon Pyo
- Department of Molecular Biology, Pusan National University, Busan 46241, Republic of Korea
| | - Young-Shin Kim
- Department of Molecular Biology, Pusan National University, Busan 46241, Republic of Korea
| | - Mi-Ae Yoo
- Department of Molecular Biology, Pusan National University, Busan 46241, Republic of Korea
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3
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Na HJ, Pyo JH, Jeon HJ, Park JS, Chung HY, Yoo MA. Deficiency of Atg6 impairs beneficial effect of metformin on intestinal stem cell aging in Drosophila. Biochem Biophys Res Commun 2018; 498:18-24. [PMID: 29496445 DOI: 10.1016/j.bbrc.2018.02.191] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Accepted: 02/26/2018] [Indexed: 12/15/2022]
Abstract
Age-related changes of adult stem cell are crucial for tissue aging and age-related diseases. Thus, clarifying mechanisms to prevent adult stem cell aging is indispensable for healthy aging. Metformin, a drug for type 2 diabetes, has been highlighted for its anti-aging and anti-cancer effect. In Drosophila intestinal stem cell (ISC), we previously reported the inhibitory effect of metformin on age-related phenotypes of ISC. Here, we showed that knockdown of Atg6, a crucial autophagy-related factor, in ISC induces age-related phenotypes of ISC such as hyperproliferation, centrosome amplification, and DNA damage accumulation. Then, we revealed that metformin inhibits ISC aging phenotypes in Atg6-dependent manner. Taken together, our study suggests that Atg6 is required for the inhibitory effect of metformin on ISC aging, providing an intervention mechanism of metformin on adult stem cell aging.
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Affiliation(s)
- Hyun-Jin Na
- Department of Molecular Biology, Pusan National University, Busan, Republic of Korea
| | - Jung-Hoon Pyo
- Department of Molecular Biology, Pusan National University, Busan, Republic of Korea
| | - Ho-Jun Jeon
- Department of Molecular Biology, Pusan National University, Busan, Republic of Korea
| | - Joung-Sun Park
- Department of Molecular Biology, Pusan National University, Busan, Republic of Korea
| | - Hae-Young Chung
- Molecular Inflammation Research Center for Aging Intervention (MRCA), College of Pharmacy, Pusan National University, Busan, Republic of Korea.
| | - Mi-Ae Yoo
- Department of Molecular Biology, Pusan National University, Busan, Republic of Korea.
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4
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Suong DNA, Shimaji K, Pyo JH, Park JS, Yoshida H, Yoo MA, Yamaguchi M. Overexpression of dJmj differentially affects intestinal stem cells and differentiated enterocytes. Cell Signal 2018; 42:194-210. [DOI: 10.1016/j.cellsig.2017.10.017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Revised: 10/19/2017] [Accepted: 10/29/2017] [Indexed: 01/17/2023]
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5
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Hwang SY, Kang YJ, Sung B, Jang JY, Hwang NL, Oh HJ, Ahn YR, Kim HJ, Shin JH, Yoo MA, Kim CM, Chung HY, Kim ND. Folic acid is necessary for proliferation and differentiation of C2C12 myoblasts. J Cell Physiol 2017; 233:736-747. [PMID: 28471487 DOI: 10.1002/jcp.25989] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2017] [Accepted: 05/03/2017] [Indexed: 02/04/2023]
Abstract
Folic acid, a water soluble B vitamin, plays an important role in cellular metabolic activities, such as functioning as a cofactor in one-carbon metabolism for DNA and RNA synthesis as well as nucleotide and amino acid biosynthesis in the body. A lack of dietary folic acid can lead to folic acid deficiency and result in several health problems, including macrocytic anemia, elevated plasma homocysteine, cardiovascular disease, birth defects, carcinogenesis, muscle weakness, and walking difficulty. However, the effect of folic acid deficiency on skeletal muscle development and its molecular mechanisms are unknown. We, therefore, investigated the effect of folic acid deficiency on myogenesis in skeletal muscle cells and found that folic acid deficiency induced proliferation inhibition and cell cycle breaking as well as cellular senescence in C2C12 myoblasts, implying that folic acid deficiency influences skeletal muscle development. Folic acid deficiency also inhibited differentiation of C2C12 myoblasts and induced deregulation of the cell cycle exit and many cell cycle regulatory genes. It inhibited expression of muscle-specific marker MyHC as well as myogenic regulatory factor (myogenin). Moreover, immunocytochemistry and Western blot analyses revealed that DNA damage was more increased in folic acid-deficient medium-treated differentiating C2C12 cells. Furthermore, we found that folic acid resupplementation reverses the effect on the cell cycle and senescence in folic acid-deficient C2C12 myoblasts but does not reverse the differentiation of C2C12 cells. Altogether, the study results suggest that folic acid is necessary for normal development of skeletal muscle cells.
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Affiliation(s)
- Seong Y Hwang
- Department of Pharmacy, College of Pharmacy, Pusan National University, Busan, Republic of Korea
| | - Yong J Kang
- Department of Pharmacy, College of Pharmacy, Pusan National University, Busan, Republic of Korea
| | - Bokyung Sung
- Department of Pharmacy, College of Pharmacy, Pusan National University, Busan, Republic of Korea
| | - Jung Y Jang
- Department of Pharmacy, College of Pharmacy, Pusan National University, Busan, Republic of Korea
| | - Na L Hwang
- Department of Pharmacy, College of Pharmacy, Pusan National University, Busan, Republic of Korea
| | - Hye J Oh
- Department of Pharmacy, College of Pharmacy, Pusan National University, Busan, Republic of Korea
| | - Yu R Ahn
- Department of Pharmacy, College of Pharmacy, Pusan National University, Busan, Republic of Korea
| | - Hong J Kim
- Department of Pharmacy, College of Pharmacy, Pusan National University, Busan, Republic of Korea
| | - Jin H Shin
- Department of Neurology, Pusan National University Yangsan Hospital, Yangsan, Republic of Korea
| | - Mi-Ae Yoo
- Department of Molecular Biology, Pusan National University, Busan, Republic of Korea
| | - Cheol M Kim
- Research Center for Anti-Aging Technology Development, Pusan National University, Busan, Republic of Korea.,Department of Biochemistry, Pusan National University School of Medicine, Yangsan, Republic of Korea
| | - Hae Y Chung
- Department of Pharmacy, College of Pharmacy, Pusan National University, Busan, Republic of Korea.,Molecular Inflammation Research Center for Aging Intervention, Pusan National University, Busan, Republic of Korea
| | - Nam D Kim
- Department of Pharmacy, College of Pharmacy, Pusan National University, Busan, Republic of Korea.,Research Center for Anti-Aging Technology Development, Pusan National University, Busan, Republic of Korea.,Molecular Inflammation Research Center for Aging Intervention, Pusan National University, Busan, Republic of Korea
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6
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Abstract
The stem cell genomic stability forms the basis for robust tissue homeostasis, particularly in high-turnover tissues. For the genomic stability, DNA damage response (DDR) is essential. This study was focused on the role of two major DDR-related factors, ataxia telangiectasia-mutated (ATM) and ATM- and RAD3-related (ATR) kinases, in the maintenance of intestinal stem cells (ISCs) in the adult Drosophila midgut. We explored the role of ATM and ATR, utilizing immunostaining with an anti-pS/TQ antibody as an indicator of ATM/ATR activation, γ-irradiation as a DNA damage inducer, and the UAS/GAL4 system for cell type-specific knockdown of ATM, ATR, or both during adulthood. The results showed that the pS/TQ signals got stronger with age and after oxidative stress. The pS/TQ signals were found to be more dependent on ATR rather than on ATM in ISCs/enteroblasts (EBs). Furthermore, an ISC/EB-specific knockdown of ATR, ATM, or both decreased the number of ISCs and oxidative stress-induced ISC proliferation. The phenotypic changes that were caused by the ATR knockdown were more pronounced than those caused by the ATM knockdown; however, our data indicate that ATR and ATM are both needed for ISC maintenance and proliferation; ATR seems to play a bigger role than does ATM.
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Affiliation(s)
- Joung-Sun Park
- Department of Molecular Biology, Pusan National University, Busan, 609-735, Republic of Korea
| | - Hyun-Jin Na
- Department of Molecular Biology, Pusan National University, Busan, 609-735, Republic of Korea
| | - Jung-Hoon Pyo
- Department of Molecular Biology, Pusan National University, Busan, 609-735, Republic of Korea
| | - Ho-Jun Jeon
- Department of Molecular Biology, Pusan National University, Busan, 609-735, Republic of Korea
| | - Young-Shin Kim
- Department of Molecular Biology, Pusan National University, Busan, 609-735, Republic of Korea
| | - Mi-Ae Yoo
- Department of Molecular Biology, Pusan National University, Busan, 609-735, Republic of Korea
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7
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Hwang SY, Kang YJ, Sung B, Kim M, Kim DH, Lee Y, Yoo MA, Kim CM, Chung HY, Kim ND. Folic acid promotes the myogenic differentiation of C2C12 murine myoblasts through the Akt signaling pathway. Int J Mol Med 2015; 36:1073-80. [PMID: 26310574 DOI: 10.3892/ijmm.2015.2311] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Accepted: 08/10/2015] [Indexed: 11/05/2022] Open
Abstract
Folic acid is a water-soluble vitamin in the B-complex group, and an exogenous intake is required for health, growth and development. As a precursor to co-factors, folic acid is required for one-carbon donors in the synthesis of DNA bases and other essential biomolecules. A lack of dietary folic acid can lead to folic acid deficiency and can therefore result in several health problems, including macrocytic anemia, elevated plasma homocysteine levels, cardiovascular disease, birth defects, carcinogenesis, muscle weakness and difficulty in walking. Previous studies have indicated that folic acid exerts a positive effect on skeletal muscle functions. However, the precise role of folic acid in skeletal muscle cell differentiation remains poorly understood. Thus, in the present study, we examined the effects of folic acid on neo-myotube maturation and differentiation using C2C12 murine myoblasts. We found that folic acid promoted the formation of multinucleated myotubes, and increased the fusion index and creatine kinase (CK) activity in a concentration-dependent manner. In addition, western blot analysis revealed that the expression levels of the muscle-specific marker, myosin heavy chain (MyHC), as well as those of the myogenic regulatory factors (MRFs), MyoD and myogenin, were increased in the folic acid-treated myotubes during myogenic differentiation. Folic acid also promoted the activation of the Akt pathway, and this effect was inhibited by treatment of the C2C12 cells with LY294002 (Akt inhibitor). Blocking of the Akt pathway with a specific inhibitor revealed that it was necessary for mediating the stimulatory effects of folic acid on muscle cell differentiation and fusion. Taken together, our data suggest that folic acid promotes the differentiation of C2C12 cells through the activation of the Akt pathway.
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Affiliation(s)
- Seong Yeon Hwang
- Department of Pharmacy, College of Pharmacy, Pusan National University, Busan 609-735, Republic of Korea
| | - Yong Jung Kang
- Department of Pharmacy, College of Pharmacy, Pusan National University, Busan 609-735, Republic of Korea
| | - Bokyung Sung
- Department of Pharmacy, College of Pharmacy, Pusan National University, Busan 609-735, Republic of Korea
| | - Minjung Kim
- Department of Pharmacy, College of Pharmacy, Pusan National University, Busan 609-735, Republic of Korea
| | - Dong Hwan Kim
- Department of Pharmacy, College of Pharmacy, Pusan National University, Busan 609-735, Republic of Korea
| | - Yujin Lee
- Department of Pharmacy, College of Pharmacy, Pusan National University, Busan 609-735, Republic of Korea
| | - Mi-Ae Yoo
- Department of Molecular Biology, Pusan National University, Busan 609-735, Republic of Korea
| | - Cheol Min Kim
- Research Center for Anti-Aging Technology Development, Pusan National University, Busan 609-735, Republic of Korea
| | - Hae Young Chung
- Department of Pharmacy, College of Pharmacy, Pusan National University, Busan 609-735, Republic of Korea
| | - Nam Deuk Kim
- Department of Pharmacy, College of Pharmacy, Pusan National University, Busan 609-735, Republic of Korea
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8
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Na HJ, Park JS, Pyo JH, Jeon HJ, Kim YS, Arking R, Yoo MA. Metformin inhibits age-related centrosome amplification in Drosophila midgut stem cells through AKT/TOR pathway. Mech Ageing Dev 2015; 149:8-18. [PMID: 25988874 DOI: 10.1016/j.mad.2015.05.004] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2015] [Revised: 04/23/2015] [Accepted: 05/06/2015] [Indexed: 12/16/2022]
Abstract
We delineated the mechanism regulating the inhibition of centrosome amplification by metformin in Drosophila intestinal stem cells (ISCs). Age-related changes in tissue-resident stem cells may be closely associated with tissue aging and age-related diseases, such as cancer. Centrosome amplification is a hallmark of cancers. Our recent work showed that Drosophila ISCs are an excellent model for stem cell studies evaluating age-related increase in centrosome amplification. Here, we showed that metformin, a recognized anti-cancer drug, inhibits age- and oxidative stress-induced centrosome amplification in ISCs. Furthermore, we revealed that this effect is mediated via down-regulation of AKT/target of rapamycin (TOR) activity, suggesting that metformin prevents centrosome amplification by inhibiting the TOR signaling pathway. Additionally, AKT/TOR signaling hyperactivation and metformin treatment indicated a strong correlation between DNA damage accumulation and centrosome amplification in ISCs, suggesting that DNA damage might mediate centrosome amplification. Our study reveals the beneficial and protective effects of metformin on centrosome amplification via AKT/TOR signaling modulation. We identified a new target for the inhibition of age- and oxidative stress-induced centrosome amplification. We propose that the Drosophila ISCs may be an excellent model system for in vivo studies evaluating the effects of anti-cancer drugs on tissue-resident stem cell aging.
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Affiliation(s)
- Hyun-Jin Na
- Department of Molecular Biology, Pusan National University, Busan 609-735, South Korea
| | - Joung-Sun Park
- Department of Molecular Biology, Pusan National University, Busan 609-735, South Korea
| | - Jung-Hoon Pyo
- Department of Molecular Biology, Pusan National University, Busan 609-735, South Korea
| | - Ho-Jun Jeon
- Department of Molecular Biology, Pusan National University, Busan 609-735, South Korea
| | - Young-Shin Kim
- Department of Molecular Biology, Pusan National University, Busan 609-735, South Korea
| | - Robert Arking
- Department of Biological Sciences, Wayne State University, Detroit, MI 48202, USA
| | - Mi-Ae Yoo
- Department of Molecular Biology, Pusan National University, Busan 609-735, South Korea.
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9
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Jeon HJ, Kim YS, Park JS, Pyo JH, Na HJ, Kim IJ, Kim CM, Chung HY, Kim ND, Arking R, Yoo MA. Age-related change in γH2AX of Drosophila muscle: its significance as a marker for muscle damage and longevity. Biogerontology 2015; 16:503-16. [PMID: 25860864 DOI: 10.1007/s10522-015-9573-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Accepted: 04/06/2015] [Indexed: 11/26/2022]
Abstract
Muscle aging is closely related to unhealthy late-life and organismal aging. Recently, the state of differentiated cells was shown to be critical to tissue homeostasis. Thus, understanding how fully differentiated muscle cells age is required for ensuring healthy aging. Adult Drosophila muscle is a useful model for exploring the aging process of fully differentiated cells. In this study, we investigated age-related changes of γH2AX, an indicator of DNA strand breaks, in adult Drosophila muscle to document whether its changes are correlated with muscle degeneration and lifespan. The results demonstrate that γH2AX accumulation increases in adult Drosophila thoracic and leg muscles with age. Analyses of short-, normal-, and long-lived strains indicate that the age-related increase of γH2AX is closely associated with the extent of muscle degeneration, cleaved caspase-3 and poly-ubiquitin aggregates, and longevity. Further analysis of muscle-specific knockdown of heterochromatin protein 1a revealed that the excessive γH2AX accumulation in thoracic and leg muscles induces accelerated degeneration and decreases longevity. These data suggest a strong correlation between age-related muscle damage and lifespan in Drosophila. Our findings indicate that γH2AX may be a reliable biomarker for assessing muscle aging in Drosophila.
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Affiliation(s)
- Ho-Jun Jeon
- Department of Molecular Biology, Pusan National University, Busan, 609-735, Republic of Korea
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10
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Kim M, Sung B, Kang YJ, Kim DH, Lee Y, Hwang SY, Yoon JH, Yoo MA, Kim CM, Chung HY, Kim ND. The combination of ursolic acid and leucine potentiates the differentiation of C2C12 murine myoblasts through the mTOR signaling pathway. Int J Mol Med 2015; 35:755-62. [PMID: 25529824 DOI: 10.3892/ijmm.2014.2046] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Accepted: 12/08/2014] [Indexed: 11/06/2022] Open
Abstract
Aging causes phenotypic changes in skeletal muscle progenitor cells that lead to the progressive loss of myogenic differentiation and thus a decrease in muscle mass. The naturally occurring triterpene, ursolic acid, has been reported to be an effective agent for the prevention of muscle loss by suppressing degenerative muscular dystrophy. Leucine, a branched-chain amino acid, and its metabolite, β-hydroxy-β-methylbutyric acid, have been reported to enhance protein synthesis in skeletal muscle. Therefore, the aim of the present study was to investigate whether the combination of ursolic acid and leucine promotes greater myogenic differentiation compared to either agent alone in C2C12 murine myoblasts. Morphological changes were observed and creatine kinase (CK) activity analysis was performed to determine the conditions through which the combination of ursolic acid and leucine would exert the most prominent effects on muscle cell differentiation. The effect of the combination of ursolic acid and leucine on the expression of myogenic differentiation marker genes was examined by RT-PCR and western blot analysis. The combination of ursolic acid (0.5 µM) and leucine (10 µM) proved to be the most effective in promoting myogenic differentiation. The combination of ursolic acid and leucine significantly increased CK activity than treatment with either agent alone. The level of myosin heavy chain, a myogenic differentiation marker protein, was also enhanced by the combination of ursolic acid and leucine. The combination of ursolic acid and leucine significantly induced the expression of myogenic differentiation marker genes, such as myogenic differentiation 1 (MyoD) and myogenin, at both the mRNA and protein level. In addition, the number of myotubes and the fusion index were increased. These findings indicate that the combination of ursolic acid and leucine promotes muscle cell differentiation, thus suggesting that this combination of agents may prove to be beneficial in increasing muscle mass.
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Affiliation(s)
- Minjung Kim
- Department of Pharmacy, College of Pharmacy, Pusan National University, Busan 609‑735, Republic of Korea
| | - Bokyung Sung
- Department of Pharmacy, College of Pharmacy, Pusan National University, Busan 609‑735, Republic of Korea
| | - Yong Jung Kang
- Department of Pharmacy, College of Pharmacy, Pusan National University, Busan 609‑735, Republic of Korea
| | - Dong Hwan Kim
- Department of Pharmacy, College of Pharmacy, Pusan National University, Busan 609‑735, Republic of Korea
| | - Yujin Lee
- Department of Pharmacy, College of Pharmacy, Pusan National University, Busan 609‑735, Republic of Korea
| | - Seong Yeon Hwang
- Department of Pharmacy, College of Pharmacy, Pusan National University, Busan 609‑735, Republic of Korea
| | - Jeong-Hyun Yoon
- Department of Pharmacy, College of Pharmacy, Pusan National University, Busan 609‑735, Republic of Korea
| | - Mi-Ae Yoo
- Department of Molecular Biology, Pusan National University, Busan 609‑735, Republic of Korea
| | - Cheol Min Kim
- Research Center for Anti‑Aging Technology Development, Pusan National University, Busan 609‑735, Republic of Korea
| | - Hae Young Chung
- Department of Pharmacy, College of Pharmacy, Pusan National University, Busan 609‑735, Republic of Korea
| | - Nam Deuk Kim
- Department of Pharmacy, College of Pharmacy, Pusan National University, Busan 609‑735, Republic of Korea
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11
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Lee SY, Jeon HM, Ju MK, Jeong EK, Kim CH, Yoo MA, Park HG, Han SI, Kang HS. Dlx-2 is implicated in TGF-β- and Wnt-induced epithelial-mesenchymal, glycolytic switch, and mitochondrial repression by Snail activation. Int J Oncol 2015; 46:1768-80. [PMID: 25651912 DOI: 10.3892/ijo.2015.2874] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Accepted: 01/05/2015] [Indexed: 01/09/2023] Open
Abstract
Epithelial-mesenchymal transition (EMT) and oncogenic metabolism (including glycolytic switch) are important for tumor development and progression. Here, we show that Dlx-2, one of distal-less (Dlx) homeobox genes, induces EMT and glycolytic switch by activation of Snail. In addition, it was induced by TGF-β and Wnt and regulates TGF-β- and Wnt-induced EMT and glycolytic switch by activating Snail. We also found that TGF-β/Wnt suppressed cytochrome c oxidase (COX), the terminal enzyme of the mitochondrial respiratory chain, in a Dlx-2/Snail-dependent manner. TGF-β/Wnt appeared to downregulate the expression of various COX subunits including COXVIc, COXVIIa and COXVIIc; among these COX subunits, COXVIc was a common target of TGF-β, Wnt, Dlx-2 and Snail, indicating that COXVIc downregulation plays an important role(s) in TGF-β/Wnt-induced COX inhibition. Taken together, our results showed that Dlx-2 is involved in TGF-β- and Wnt-induced EMT, glycolytic switch, and mitochondrial repression by Snail activation.
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Affiliation(s)
- Su Yeon Lee
- Department of Molecular Biology, College of Natural Sciences, Pusan National University, Pusan 609-735, Republic of Korea
| | - Hyun Min Jeon
- Department of Molecular Biology, College of Natural Sciences, Pusan National University, Pusan 609-735, Republic of Korea
| | - Min Kyung Ju
- Department of Molecular Biology, College of Natural Sciences, Pusan National University, Pusan 609-735, Republic of Korea
| | - Eui Kyong Jeong
- Department of Molecular Biology, College of Natural Sciences, Pusan National University, Pusan 609-735, Republic of Korea
| | - Cho Hee Kim
- Department of Molecular Biology, College of Natural Sciences, Pusan National University, Pusan 609-735, Republic of Korea
| | - Mi-Ae Yoo
- Department of Molecular Biology, College of Natural Sciences, Pusan National University, Pusan 609-735, Republic of Korea
| | - Hye Gyeong Park
- Nanobiotechnology Center, Pusan National University, Pusan 609-735, Republic of Korea
| | - Song Iy Han
- The Division of Natural Medical Sciences, College of Health Science, Chosun University, Gwangju 501-759, Republic of Korea
| | - Ho Sung Kang
- Department of Molecular Biology, College of Natural Sciences, Pusan National University, Pusan 609-735, Republic of Korea
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12
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Pyo JH, Park JS, Na HJ, Jeon HJ, Lee SH, Kim JG, Park SY, Jin YW, Kim YS, Yoo MA. Functional Modification of Drosophila Intestinal Stem Cells by Ionizing Radiation. Radiat Res 2014; 181:376-86. [DOI: 10.1667/rr13545.1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- Jung-Hoon Pyo
- Department of Molecular Biology, Pusan National University, Busan 609–735, Korea
| | - Joung-Sun Park
- Department of Molecular Biology, Pusan National University, Busan 609–735, Korea
| | - Hyun-Jin Na
- Department of Molecular Biology, Pusan National University, Busan 609–735, Korea
| | - Ho-Jun Jeon
- Department of Molecular Biology, Pusan National University, Busan 609–735, Korea
| | - Shin-Hae Lee
- Department of Molecular Biology, Pusan National University, Busan 609–735, Korea
| | - Joong-Gook Kim
- Department of Molecular Biology, Pusan National University, Busan 609–735, Korea
| | - So-Young Park
- Division of Brain Diseases, Center for Biomedical Sciences, Korea National Institute of Health, Chungcheongbuk-do 363–951, Korea
| | - Young-Woo Jin
- National Radiation Emergency Center, Korea Institute of Radiological & Medical Sciences, Seoul 139–706, Korea; and
| | - Young-Shin Kim
- Research Institute of Genetic Engineering, Pusan National University, Busan 609–735, Korea
| | - Mi-Ae Yoo
- Department of Molecular Biology, Pusan National University, Busan 609–735, Korea
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Na HJ, Park JS, Pyo JH, Lee SH, Jeon HJ, Kim YS, Yoo MA. Mechanism of metformin: inhibition of DNA damage and proliferative activity in Drosophila midgut stem cell. Mech Ageing Dev 2013; 134:381-90. [PMID: 23891756 DOI: 10.1016/j.mad.2013.07.003] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2013] [Revised: 06/13/2013] [Accepted: 07/14/2013] [Indexed: 02/06/2023]
Abstract
Age-related changes in stem cells could have a profound impact on tissue aging and the development of age-related diseases such as cancer. However, the effects of metformin, a recently recognized anti-cancer drug, on stem cell aging remain largely unknown. In the present study, an experiment was set up to investigate the underlying mechanism of metformin's beneficial effects on age-related changes in intestinal stem cells (ISCs) derived from Drosophila midgut. Results showed that metformin reduced age- and oxidative stress-related accumulation of DNA damage marked by Drosophila γH2AX foci and 8-oxo-dG in ISCs and progenitor cells. Metformin also inhibited age and- oxidative stress-related ISC hyperproliferation as well as intestinal hyperplasia. Our study further revealed that the inhibitory effects of metformin on DNA damage accumulation may be due to the down-regulation of age-related and oxidative stress-induced AKT activity. These data indicate that metformin has beneficial effects on age-related changes in ISCs derived from Drosophila midgut. Further, our results suggest a possible impact of DNA damage on stem cell genomic instability, which leads to the development of age-related diseases. Additionally, our study suggests that Drosophila midgut stem cells can be a suitable model system for studying stem cell biology and stem cell aging.
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Affiliation(s)
- Hyun-Jin Na
- Department of Molecular Biology, College of Natural Science, Pusan National University, Busan 609-735, Republic of Korea
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14
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Kwon HJ, Sung BK, Kim JW, Lee JH, Kim ND, Yoo MA, Kang HS, Baek HS, Bae SJ, Choi JS, Takahashi R, Goto S, Chung HY. The effect of lipopolysaccharide on enhanced inflammatory process with age: Modulation of NF-κB. J Am Aging Assoc 2013; 24:163-71. [PMID: 23604881 DOI: 10.1007/s11357-001-0017-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Oxidative stress is thought to be a causative factor for age-related damage in a wide variety of cellular constituents that can lead to dysfunction and various pathological conditions, including the inflammatory process. At the molecular level, the redox-sensitive transcription factor, NF-κB plays a key role in the regulation of the inflammatory process, along with cytokines, cyclooxygenase-2 (COX-2), and inducible nitric oxide synthase (iNOS). We studied the mechanism underlying the modulation of the inflammatory reaction with age by investigating NF-κB activation and the expression of COX-2, iNOS, and cytokines genes in hepatic tissues isolated from young and old rats. We expanded our investigation of these factors in rats injected with the inflammatory activator, lipopolysaccharide (LPS). Data showed that NF-κB activity was up-regulated with age and was further enhanced by LPS injection, indicating an increased susceptibility and sensitivity to the inflammatory stimulus with age. To explore further the molecular events leading to NF-κB activation, we investigated the inhibitory component of NF-κB complex, IκB. Cytosolic IκBα, but not IκBβ, was significantly decreased in both old and LPS-treated rats, signifying the enhanced migration of cytosolic NF-κB complex into the nucleus following dissociation from the inhibitor. The appearance of the polypeptide, p65, as determined in the nucleus, corresponded with the change in IκBα, providing further supporting evidence for the molecular process involved in NF-κB activation. Our additional investigation of two proinflammatory-related enzymes, COX-2 and iNOS, and three cytokines, interleukin-1β (IL-1β), interleukin-6 (IL-6), and tumor necrosis factor-α, clearly showed aged-related increases, in corroboration with the NF-κB activation. Our results demonstrated that LPS injection caused the enhanced gene expression of inducible proinflammatory proteins, COX-2 and iNOS through NF-κB activation.
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Affiliation(s)
- H J Kwon
- College of Pharmacy, Pusan National University, Pusan, 609-735 Korea
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15
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Kim YS, Nam HJ, Chung HY, Kim ND, Ryu JH, Lee WJ, Arking R, Yoo MA. Role of xanthine dehydrogenase and aging on the innate immune response of Drosophila. J Am Aging Assoc 2013; 24:187-93. [PMID: 23604884 DOI: 10.1007/s11357-001-0020-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
It has been proposed that uric acid is an important scavenger of deleterious oxygen species and peroxynitrite in biological systems. The cellular sources responsible for the generation of damage-causing reactive oxygen species (ROS) are widespread. Xanthine dehydrogenase (XDH) / oxidase (XOD) catalyzes the oxidation of xanthine to uric acid. The rosy (ry) gene encodes XDH/XOD in Drosophila melanogaster. XDH codes for uric acid which is a ROS scavenger. XOD however is an enzyme system implicated in ROS production. In this study, we investigated the roles of XDH in the fly's immune defense response to infection and in the aging process. We first compared ROS generation and nitric oxide (NO) level in the whole body and the gut of XDH mutant with those of wild type. Our results suggested that XDH has a protective effect with respect to both ROS and NO generations, particularly in the gut. We also examined the effect of a XDH deletion mutant on the relative sensitivity of the organism against bacterial infection, on the immune inducibility of antimicrobial peptides and on the effect of aging in the defensive response to infection. Our results strongly suggest that XDH plays an important role in the innate immune response and that the age-associated deterioration of the innate immune response might be, at least in part, associated with the loss of XDH activity in the aging process.
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Affiliation(s)
- Y S Kim
- Department of Molecular Biology, Pusan National University, Gumjung-ku, Pusan, 609-735 ; Institute of Genetic Engineering, Pusan National University, Gumjung-ku, Pusan, 609-735
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16
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Park JS, Choi YJ, Thao DTP, Kim YS, Yamaguchi M, Yoo MA. DREF is involved in the steroidogenesis via regulation of shadow gene. Am J Cancer Res 2012; 2:714-725. [PMID: 23226617 PMCID: PMC3512185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2012] [Accepted: 10/21/2012] [Indexed: 06/01/2023] Open
Abstract
The Drosophila DNA replication-related element-binding factor (dDREF) has been identified as a master regulator of cell proliferation-related genes via its binding to the DRE sequence, 5'-TATCGATA. However, the biological roles of DREF are still to be clarified. Here, we show that DREF mutant females have steroid hormone ecdysone-deficient phenotypes, such as the loss of vitellogenic egg chambers. Furthermore, DREF knockdown in the prothoracic gland of larva prevented pupation and this was rescued via 20-hydroxyecdysone treatment. We found a DRE-like sequence (-625 to -632) in the 5'-flanking region of the Drosophila shadow gene, which catalyzes the conversion of 2-deoxyecdysone to ecdysone, and demonstrated that shadow is a novel target gene of dDREF using quantitative RT-PCR and Chip assays. In addition, we show that the level of dDREF protein correlated with age-related changes in the level of shadow mRNA in the ovaries of wild-type flies. Taken together, our data indicate that dDREF plays a key role in steroid synthesis via regulation of the shadow gene.
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Affiliation(s)
- Joung-Sun Park
- Department of Molecular Biology, Pusan National UniversityBusan 609-735, Republic of Korea
| | - Yoon-Jeong Choi
- Department of Molecular Biology, Pusan National UniversityBusan 609-735, Republic of Korea
| | - Dang Thi Phuong Thao
- Department of Applied Biology, Insect Biomedical Research Center, Kyoto Institute of TechnologyMatsugasaki, Sakyo-ku, Kyoto 606-8585, Japan
- Present address: Department of Molecular and Environmental Biotechnology, University of Science, Vietnam National University in Ho Chi Minh CityVietnam
| | - Young-Shin Kim
- Research Institute of Genetic Engineering, Pusan National UniversityBusan 609-735, Republic of Korea
| | - Masamitsu Yamaguchi
- Department of Applied Biology, Insect Biomedical Research Center, Kyoto Institute of TechnologyMatsugasaki, Sakyo-ku, Kyoto 606-8585, Japan
| | - Mi-Ae Yoo
- Department of Molecular Biology, Pusan National UniversityBusan 609-735, Republic of Korea
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Shin MK, Kim MJ, Baek JH, Yoo MA, Koh JS, Lee SJ, Lee MH. Analysis of the temporal change in biophysical parameters after fractional laser treatments using reflectance confocal microscopy. Skin Res Technol 2012; 19:e515-20. [DOI: 10.1111/srt.12003] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/09/2012] [Indexed: 11/30/2022]
Affiliation(s)
- Min-Kyung Shin
- Department of Dermatology; College of Medicine; Kyung Hee University; Seoul; Korea
| | - Min-Joong Kim
- Department of Dermatology; College of Medicine; Kyung Hee University; Seoul; Korea
| | | | - Mi-Ae Yoo
- Dermapro/Skin research Center; Seoul; Korea
| | | | | | - Mu-Hyoung Lee
- Department of Dermatology; College of Medicine; Kyung Hee University; Seoul; Korea
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Lee SH, Park JS, Kim YS, Chung HY, Yoo MA. Requirement of matrix metalloproteinase-1 for intestinal homeostasis in the adult Drosophila midgut. Exp Cell Res 2012; 318:670-81. [DOI: 10.1016/j.yexcr.2012.01.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2011] [Revised: 12/29/2011] [Accepted: 01/03/2012] [Indexed: 12/20/2022]
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Lee SH, Kim IJ, Kim JG, Park JS, Kim YS, Yamaguchi M, Kim CM, Yoo MA. Regulation of intestinal stem cell proliferation by human methyl-CpG-binding protein-2 in Drosophila. Cell Struct Funct 2011; 36:197-208. [PMID: 21979236 DOI: 10.1247/csf.11027] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Recent studies have suggested the involvement of epigenetic factors such as methyl-CpG-binding protein-2 (MeCP2) in tumorigenesis. In addition, cancer may represent a stem cell-based disease, suggesting that understanding of stem cell regulation could provide valuable insights into the mechanisms of tumorigenesis. However, the function of epigenetic factors in stem cell regulation in adult tissues remains poorly understood. In the present study, we investigated the role of human MeCP2 (hMeCP2), a bridge factor linked to DNA modification and histone modification, in stem cell proliferation using adult Drosophila midgut, which appears to be an excellent model system to study stem cell biology. Results show that enterocyte (EC)-specific expression of hMeCP2 in adult midgut using an exogenous GAL4/UAS expression system induced intestinal stem cell (ISC) proliferation marked by staining with anti-phospho-histone H3 antibody and BrdU incorporation assays. In addition, hMeCP2 expression in ECs activated extracellular stress-response kinase signals in ISCs. Furthermore, expression of hMeCP2 modulated the distribution of heterochromatin protein-1 in ECs. Our data suggests the hypothesis that the expression of hMeCP2 in differentiated ECs stimulates ISC proliferation, implying a role of MeCP2 as a stem cell regulator.
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Affiliation(s)
- Shin-Hae Lee
- Department of Molecular Biology, College of Natural Science, Pusan National University, Busan, Republic of Korea
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20
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Park SY, Jeong MS, Yoo MA, Jang SB. Caudal-related homeodomain proteins CDX1/2 bind to DNA replication-related element binding factor. Biochim Biophys Acta 2011; 1814:1891-9. [PMID: 21821154 DOI: 10.1016/j.bbapap.2011.07.021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2011] [Revised: 07/19/2011] [Accepted: 07/22/2011] [Indexed: 12/28/2022]
Abstract
In the intestinal epithelium, the CDX1 and CDX2 homeodomain genes play proliferative and tumor suppressor roles, respectively. The transcription factor DNA replication-related element binding factor (DREF), is an 80kDa polypeptide homodimer that plays an important role in regulating cell proliferation-related genes. Homeodomain genes encode DNA-binding proteins that play crucial roles during development by defining the body plan and determining cell fate. However, until now, the regulation of DREF function by caudal-related homeodomain proteins is poorly understood. In this study, recombinant CDX1/2 homeodomains (CDX1, amino acids [aa] 152-216 and CDX2, aa 184-248) and the DNA-binding domain of Drosophila DREF (dDREF; aa 1-125) were isolated in order to investigate the regulatory mechanism of their interaction. The expression and purification of the truncated CDX1/2 and DREF proteins were successfully performed in Escherichia coli. Models of the CDX1/2 homeodomain and dDREF were constructed using SWISS-MODEL software, a program for relative protein structure modeling. The binding of CDX1/2 and DREF proteins was detected by fluorescence measurement, size-exclusion column (SEC) chromatography, His-tagged pull-down assay, and surface plasmon resonance spectroscopy (BIAcore). In addition, we identified that four different mutants of CDX1 (S185A, N190A, T194A, and V212A) were bound to dDREF with different degrees of interaction. Our results indicate that CDX1/2 homeodomains interact with the DNA-binding domain of dDREF, thereby regulating its transcription activity.
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Affiliation(s)
- So Young Park
- Department of Molecular Biology, Pusan National University, Busan, Republic of Korea
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21
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Kim CH, Jeon HM, Lee SY, Ju MK, Moon JY, Park HG, Yoo MA, Choi BT, Yook JI, Lim SC, Han SI, Kang HS. Implication of snail in metabolic stress-induced necrosis. PLoS One 2011; 6:e18000. [PMID: 21448462 PMCID: PMC3063248 DOI: 10.1371/journal.pone.0018000] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2010] [Accepted: 02/22/2011] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Necrosis, a type of cell death accompanied by the rupture of the plasma membrane, promotes tumor progression and aggressiveness by releasing the pro-inflammatory and angiogenic cytokine high mobility group box 1. It is commonly found in the core region of solid tumors due to hypoxia and glucose depletion (GD) resulting from insufficient vascularization. Thus, metabolic stress-induced necrosis has important clinical implications for tumor development; however, its regulatory mechanisms have been poorly investigated. METHODOLOGY/PRINCIPAL FINDINGS Here, we show that the transcription factor Snail, a key regulator of epithelial-mesenchymal transition, is induced in a reactive oxygen species (ROS)-dependent manner in both two-dimensional culture of cancer cells, including A549, HepG2, and MDA-MB-231, in response to GD and the inner regions of a multicellular tumor spheroid system, an in vitro model of solid tumors and of human tumors. Snail short hairpin (sh) RNA inhibited metabolic stress-induced necrosis in two-dimensional cell culture and in multicellular tumor spheroid system. Snail shRNA-mediated necrosis inhibition appeared to be linked to its ability to suppress metabolic stress-induced mitochondrial ROS production, loss of mitochondrial membrane potential, and mitochondrial permeability transition, which are the primary events that trigger necrosis. CONCLUSIONS/SIGNIFICANCE Taken together, our findings demonstrate that Snail is implicated in metabolic stress-induced necrosis, providing a new function for Snail in tumor progression.
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Affiliation(s)
- Cho Hee Kim
- Department of Molecular Biology, College of Natural Sciences, Pusan National University, Pusan, Korea
| | - Hyun Min Jeon
- Department of Molecular Biology, College of Natural Sciences, Pusan National University, Pusan, Korea
| | - Su Yeon Lee
- Department of Molecular Biology, College of Natural Sciences, Pusan National University, Pusan, Korea
| | - Min Kyung Ju
- Department of Molecular Biology, College of Natural Sciences, Pusan National University, Pusan, Korea
| | - Ji Young Moon
- Department of Molecular Biology, College of Natural Sciences, Pusan National University, Pusan, Korea
| | - Hye Gyeong Park
- Nanobiotechnology Center, Pusan National University, Pusan, Korea
| | - Mi-Ae Yoo
- Department of Molecular Biology, College of Natural Sciences, Pusan National University, Pusan, Korea
| | - Byung Tae Choi
- Division of Meridian and Structural Medicine, School of Oriental Medicine, Pusan National University, Pusan, Korea
| | - Jong In Yook
- Department of Oral Pathology, Oral Cancer Research Institute, College of Dentistry, Yonsei University, Seoul, Korea
| | - Sung-Chul Lim
- Research Center for Resistant Cells, College of Medicine, Chosun University, Gwangju, Korea
- Department of Pathology, College of Medicine, Chosun University, Gwangju, Korea
| | - Song Iy Han
- Research Center for Resistant Cells, College of Medicine, Chosun University, Gwangju, Korea
| | - Ho Sung Kang
- Department of Molecular Biology, College of Natural Sciences, Pusan National University, Pusan, Korea
- * E-mail:
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Hwang MS, Lee SJ, Jeong HE, Lee S, Yoo MA, Shin JG. Genetic variations in UDP-glucuronosyltransferase 2B7 gene (UGT2B7) in a Korean population. Drug Metab Pharmacokinet 2010; 25:398-402. [PMID: 20814162 DOI: 10.2133/dmpk.dmpk-10-sc-021] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Glucuronidation by UDP-glucuronosyltransferase 2B7 (UGT2B7) has been identified as an important pathway for the elimination of its substrate drugs in humans. Alterations in UGT2B7 function or expression may influence individual variations in drug responses. In an effort to screen for UGT2B7 single nucleotide polymorphisms (SNPs) in Koreans, the UGT2B7 gene was directly sequenced in 50 normal subjects. A total of 19 genetic variations were found: seven in exons, eight in introns, and four in the 5'-untranslated region. The order of the frequency distribution of UGT2B7 variations was: -900A>G, -327G>A, -161C>T, 10539A>G, 10711G>C and 10806T>A (40%); 2099T>A, 2100C>T, 2283A>G and 2316A>G (39%); 12029T>A (37%); 10928C>A (33%); 10541G>A (28%); 10897insA (24%); 372A>G (13%) and 211G>T (12%), as well as other minor alleles with less than 10% frequency. Nineteen variations were used to characterize linkage disequilibrium (LD) structures at the UGT2B7 locus. Eight tagging SNPs in UGT2B7 were determined. Identification of UGT2B7 SNPs with LD and the tagging SNPs lays the foundation for investigating UGT2B7-related genotype/phenotype association studies for Koreans as well as other populations.
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Affiliation(s)
- Mi-Sun Hwang
- Department of Pharmacology and Pharmacogenomics Research Center, Busan, Korea
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Yang DJ, Chung JY, Lee SJ, Park SY, Pyo JH, Ha NC, Yoo MA, Park BJ. Slug, mammalian homologue gene of Drosophila escargot, promotes neuronal-differentiation through suppression of HEB/daughterless. Cell Cycle 2010; 9:2789-2802. [PMID: 20647756] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/29/2023] Open
Abstract
At the neuron developmental stage, neuron-precursor cells can be differentiated into neuron or glia cells. However, precise molecular mechanism to determine the cell fate has not been clearly demonstrated. In this study, we reveal that Drosophila esgarcot and its mammalian homologue genes, Snail and Slug, play a key role in neuronal differentiation. In Drosophila model system, overexpression of Esg, like as Wingless, suppresses the bristle formation. In contrast, elimination of Esg though RNAi promotes double bristle phenotype. We can also observe the similar phenotype in Snail-overexpression system. In mammalian system, overexpression of Slug or Snail can induce neuronal differentiation. Esg and its mammalian homologue gene Slug directly interact with Daughtherless and its mammalian homologue HEB and eliminate them through siah-1 mediated protein degradation. Thus, overexpression of siah-1 can promote neuron cell differentiation, whereas si-siah-1 blocks the Slug-induced HEB suppression. In fact, Drosophila SINA, Siah-1 homologue, has been also known to be involved in bristle formation and Neuronal differentiation. In addition, it has been revealed that CK1 is involved in Esg or Snail stability and Neuronal differentiation. However, Snail is regulated only by CK1 but not by Siah. Considering the fact that Slug mutations have been found in human genetic disease, waardenberg syndrome, major symptoms of which is loss of hearing neuron and odd eye, our result implies that slug/Snail system is required for proper neuronal differentiation, like as Esg in Drosophila.
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Affiliation(s)
- Dong-Jin Yang
- Department of Molecular Biology, College of Natural Science, Pusan National University, Busan, Korea
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Yang DJ, Chung JY, Lee SJ, Park SY, Pyo JH, Ha NC, Yoo MA, Park BJ. Slug, mammalian homologue gene of Drosophila escargot, promotes neuronal-differentiation through suppression of HEB/daughterless. Cell Cycle 2010. [DOI: 10.4161/cc.9.14.12247] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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Jeong MS, Hwang EY, Kim HT, Yoo MA, Jang SB. Purification of caudal-related homeodomain transcription factor and its binding characterization. J Microbiol Biotechnol 2010; 19:1557-64. [PMID: 20075618 DOI: 10.4014/jmb.0905.05021] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
Abstract
Human CDX2 is known as a caudal-related homeodomain transcription factor that is expressed in the intestinal epithelium and is important in differentiation and maintenance of the intestinal epithelial cells. The caudal-related homeobox proteins bind DNA according to a helix-turn-helix structure, thereby increasing the structural stability of DNA. A cancer-tumor suppressor role for Cdx2 has been shown by a decrease in the level of the expression of Cdx2 in colorectal cancer but the mechanism of transcriptional regulation has not been examined at the molecular level. We developed a large-scale system for expression of the recombinant, novel CDX2, in the Escherichia coli. A highly purified and soluble CDX2 protein was obtained in E. coli strain BL21(DE3)RIL and a hexahistidine fusion system using Ni-NTA affinity column, anion exchange, and gel filtration chromatography. The identity and secondary structure of the purified CDX2 protein were confirmed by MALDI-TOF MS, Western blot, and a circular dichroism analyses. In addition, we studied the DNA binding activity of recombinant CDX2 by ELISA experiment and isolated human CDX2 binding proteins derived from rat cells by an immobilized GST-fusion method. Three CDX2-binding proteins were found in the gastric tissue, and those proteins were identified to the homeobox protein Hox-D8, LIM homeobox protein 6, and SMC1L1 protein.
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Affiliation(s)
- Mi Suk Jeong
- Department of Molecular Biology, College of Natural Sciences, Pusan National University, Busa, Korea
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Park JS, Kim YS, Kim JG, Lee SH, Park SY, Yamaguchi M, Yoo MA. Regulation of the Drosophila p38b gene by transcription factor DREF in the adult midgut. Biochim Biophys Acta 2010; 1799:510-9. [PMID: 20346429 DOI: 10.1016/j.bbagrm.2010.03.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2010] [Revised: 03/17/2010] [Accepted: 03/18/2010] [Indexed: 01/14/2023]
Abstract
The Drosophila midgut is an excellent model for evaluation of gene networks that regulate adult stem cell proliferation and differentiation. The Drosophila p38b (D-p38b) gene has been shown to be involved in intestinal stem cell (ISC) proliferation and differentiation in the adult midgut. Here, we report that D-p38b gene expression is regulated by DREF (DNA replication-related element binding factor) in the adult midgut. We have identified a DRE in the 5'-flanking region of the D-p38b gene and showed that DREF could bind to this DRE via a gel mobility shift assay and a ChIP assay. Base-substitution mutations of the D-p38b promoter DRE and analyses of transformants carrying D-p38b-lacZ or D-p38b-DREmut-lacZ indicated that this DRE is required for the activity of the D-p38b gene promoter. Furthermore, by using the GAL4-UAS system, we showed that DREF regulates the activity of the D-p38b gene promoter in adult ISCs and progenitors. In addition, the D-p38b knockdown phenotypes in the midgut were rescued by DREF overexpression, suggesting a functional link between these two factors. Our results suggest that the D-p38b gene is regulated by the DREF pathway and that DREF is involved in the regulation of proliferation and differentiation of Drosophila ISCs and progenitors.
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Affiliation(s)
- Joung-Sun Park
- Department of Molecular Biology, Pusan National University, Busan 609-735, Korea
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27
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Hong SE, Heo HS, Kim DH, Kim MS, Kim CH, Lee J, Yoo MA, Yu BP, Leeuwenburgh C, Chung HY. Revealing system-level correlations between aging and calorie restriction using a mouse transcriptome. Age (Dordr) 2010; 32:15-30. [PMID: 19590981 PMCID: PMC2829640 DOI: 10.1007/s11357-009-9106-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/26/2008] [Accepted: 06/17/2009] [Indexed: 05/28/2023]
Abstract
Although systems biology is a perfect framework for investigating system-level declines during aging, only a few reports have focused on a comprehensive understanding of system-level changes in the context of aging systems. The present study aimed to understand the most sensitive biological systems affected during aging and to reveal the systems underlying the crosstalk between aging and the ability of calorie restriction (CR) to effectively slow-down aging. We collected and analyzed 478 aging- and 586 CR-related mouse genes. For the given genes, the biological systems that are significantly related to aging and CR were examined according to three aspects. First, a global characterization by Gene Ontology (GO) was performed, where we found that the transcriptome (a set of genes) for both aging and CR were strongly related in the immune response, lipid metabolism, and cell adhesion functions. Second, the transcriptional modularity found in aging and CR was evaluated by identifying possible functional modules, sets of genes that show consistent expression patterns. Our analyses using the given functional modules, revealed systemic interactions among various biological processes, as exemplified by the negative relation shown between lipid metabolism and the immune response at the system level. Third, transcriptional regulatory systems were predicted for both the aging and CR transcriptomes. Here, we suggest a systems biology framework to further understand the most important systems as they age.
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Affiliation(s)
- Seong-Eui Hong
- Department of Life Science, Gwangju Institute of Science and Technology, 1 Oryong-dong, Buk-gu, Gwangju, 500-712 Republic of Korea
| | - Hyoung-Sam Heo
- Interdisciplinary Research Program of Bioinformatics, College of Natural Science, Pusan National University, Gumjung-gu, Busan 609-735 Republic of Korea
| | - Dae Hyun Kim
- Department of Pharmacy, Aging Tissue Bank, College of Pharmacy, Pusan National University, 30 Changjeon-dong, Kumjung-gu, Busan 609-735 Republic of Korea
| | - Min-Sun Kim
- Department of Pharmacy, Aging Tissue Bank, College of Pharmacy, Pusan National University, 30 Changjeon-dong, Kumjung-gu, Busan 609-735 Republic of Korea
| | - Chul Hong Kim
- Korean BioInformation Center, Korea Research Institute of Bioscience and Biotechnology, 52 Eoeun-dong, Yooseong-goo, Daejeon 305-333 Republic of Korea
| | - Jaewon Lee
- Department of Pharmacy, Aging Tissue Bank, College of Pharmacy, Pusan National University, 30 Changjeon-dong, Kumjung-gu, Busan 609-735 Republic of Korea
| | - Mi-Ae Yoo
- Department of Molecular Biology, College of Natural Sciences, Pusan National University, Gumjung-gu, Busan 609-735 Republic of Korea
| | - Byung Pal Yu
- Department of Physiology, The University of Texas Health Science Center at San Antonio, San Antonio, TX 78229 USA
| | - Christiaan Leeuwenburgh
- Department of Aging and Geriatrics, College of Medicine, University of Florida, Gainesville, FL 21611-2610 USA
| | - Hae Young Chung
- Department of Pharmacy, Aging Tissue Bank, College of Pharmacy, Pusan National University, 30 Changjeon-dong, Kumjung-gu, Busan 609-735 Republic of Korea
- Department of Aging and Geriatrics, College of Medicine, University of Florida, Gainesville, FL 21611-2610 USA
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Park JS, Kim YS, Yoo MA. The role of p38b MAPK in age-related modulation of intestinal stem cell proliferation and differentiation in Drosophila. Aging (Albany NY) 2009; 1:637-51. [PMID: 20157545 PMCID: PMC2806044 DOI: 10.18632/aging.100054] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2009] [Accepted: 05/20/2009] [Indexed: 04/12/2023]
Abstract
It is important to understand how age-related changes in intestinal stem cells (ISCs) may contribute to age-associated intestinal diseases, including cancer. Drosophila midgut is an excellent model system for the study of ISC proliferation and differentiation. Recently, age-related changes in the Drosophila midgut have been shown to include an increase in ISC proliferation and accumulation of mis-differentiated ISC daughter cells. Here, we show that the p38b MAPK pathway contributes to the age-related changes in ISC and progenitor cells in Drosophila. D-p38b MAPK is required for an age-related increase of ISC proliferation. In addition, this pathway is involved in age and oxidative stress-associated mis-differentiation of enterocytes and upregulation of Delta, a Notch receptor ligand. Furthermore, we also show that D-p38b acts downstream of PVF2/PVR signaling in these age-related changes. Taken together, our findings suggest that p38 MAPK plays a crucial role in the balance between ISC proliferation and proper differentiation in the adult Drosophila midgut.
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Affiliation(s)
- Joung-Sun Park
- Department of Molecular Biology, Pusan National University, Busan 609-735, Korea
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Park JS, Kim SR, Park SY, Yang DJ, Lee SH, Choi YJ, Bae MK, Yamaguchi M, Kim YS, Yoo MA. Big brain, a Drosophila homologue of mammalian aquaporin, is regulated by the DRE/DREF system. Biochimica et Biophysica Acta (BBA) - Gene Regulatory Mechanisms 2008; 1779:789-96. [DOI: 10.1016/j.bbagrm.2008.07.015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2007] [Revised: 07/19/2008] [Accepted: 07/28/2008] [Indexed: 11/28/2022]
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Abstract
Age-associated changes in stem cell populations have been implicated in age-related diseases, including cancer. However, little is known about the underlying molecular mechanisms that link aging to the modulation of adult stem cell populations. Drosophila midgut is an excellent model system for the study of stem cell renewal and aging. Here we describe an age-related increase in the number and activity of intestinal stem cells (ISCs) and progenitor cells in Drosophila midgut. We determined that oxidative stress, induced by paraquat treatment or loss of catalase function, mimicked the changes associated with aging in the midgut. Furthermore, we discovered an age-related increase in the expression of PVF2, a Drosophila homologue of human PDGF/VEGF, which was associated with and required for the age-related changes in midgut ISCs and progenitor cell populations. Taken together, our findings suggest that PDGF/VEGF may play a central role in age-related changes in ISCs and progenitor cell populations, which may contribute to aging and the development of cancer stem cells.
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Affiliation(s)
- Na-Hyun Choi
- Department of Molecular Biology, College of Natural Science, Pusan National UniversityBusan 609-735, South Korea
| | - Joong-Gook Kim
- Department of Molecular Biology, College of Natural Science, Pusan National UniversityBusan 609-735, South Korea
| | - Dong-Jin Yang
- Department of Molecular Biology, College of Natural Science, Pusan National UniversityBusan 609-735, South Korea
| | - Young-Shin Kim
- Research Institute of Genetic Engineering, Pusan National UniversityBusan 609-735, South Korea
| | - Mi-Ae Yoo
- Department of Molecular Biology, College of Natural Science, Pusan National UniversityBusan 609-735, South Korea
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31
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Kim SR, Bae YH, Bae SK, Choi KS, Yoon KH, Koo TH, Jang HO, Yun I, Kim KW, Kwon YG, Yoo MA, Bae MK. Visfatin enhances ICAM-1 and VCAM-1 expression through ROS-dependent NF-kappaB activation in endothelial cells. Biochim Biophys Acta 2008; 1783:886-95. [PMID: 18241674 DOI: 10.1016/j.bbamcr.2008.01.004] [Citation(s) in RCA: 219] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2007] [Revised: 12/26/2007] [Accepted: 01/03/2008] [Indexed: 12/13/2022]
Abstract
Visfatin has recently been identified as a novel visceral adipokine which may be involved in obesity-related vascular disorders. However, it is not known whether visfatin directly contributes to endothelial dysfunction. Here, we investigated the effect of visfatin on vascular inflammation, a key step in a variety of vascular diseases. Visfatin induced leukocyte adhesion to endothelial cells and the aortic endothelium by induction of the cell adhesion molecules, ICAM-1 and VCAM-1. Promoter analysis revealed that visfatin-mediated induction of CAMs is mainly regulated by nuclear factor-kappaB (NF-kappaB). Visfatin stimulated IkappaBalpha phosphorylation, nuclear translocation of the p65 subunit of NF-kappaB, and NF-kappaB DNA binding activity in HMECs. Furthermore, visfatin increased ROS generation, and visfatin-induced CAMs expression and NF-kappaB activation were abrogated in the presence of the direct scavenger of ROS. Taken together, our results demonstrate that visfatin is a vascular inflammatory molecule that increases expression of the inflammatory CAMs, ICAM-1 and VCAM-1, through ROS-dependent NF-kappaB activation in endothelial cells.
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Affiliation(s)
- Su-Ryun Kim
- School of Dentistry, Pusan National University, Pusan, South Korea
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Kim SR, Bae SK, Choi KS, Park SY, Jun HO, Lee JY, Jang HO, Yun I, Yoon KH, Kim YJ, Yoo MA, Kim KW, Bae MK. Visfatin promotes angiogenesis by activation of extracellular signal-regulated kinase 1/2. Biochem Biophys Res Commun 2007; 357:150-6. [PMID: 17408594 DOI: 10.1016/j.bbrc.2007.03.105] [Citation(s) in RCA: 109] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2007] [Accepted: 03/17/2007] [Indexed: 11/17/2022]
Abstract
Adipose tissue is highly vascularized and requires the angiogenic properties for its mass growth. Visfatin has been recently characterized as a novel adipokine, which is preferentially produced by adipose tissue. In this study, we report that visfatin potently stimulates in vivo neovascularization in chick chorioallantoic membrane and mouse Matrigel plug. We also demonstrate that visfatin activates migration, invasion, and tube formation in human umbilical vein endothelial cells (HUVECs). Moreover, visfatin evokes activation of the extracellular signal-regulated kinase 1/2 (ERK1/2) in endothelial cells, which is closely linked to angiogenesis. Inhibition of ERK activation markedly decreases visfatin-induced tube formation of HUVECs and visfatin-stimulated endothelial cell sprouting from rat aortic rings. Taken together, these results demonstrate that visfatin promotes angiogenesis via activation of mitogen-activated protein kinase ERK-dependent pathway and suggest that visfatin may play important roles in various pathophysiological angiogenesis including adipose tissue angiogenesis.
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Affiliation(s)
- Su-Ryun Kim
- School of Dentistry, Pusan National University, Pusan 602-739, Republic of Korea
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Choi YJ, Kwon EJ, Park JS, Kang HS, Kim YS, Yoo MA. Transcriptional regulation of the Drosophila caudal homeobox gene by bHLH-PAS proteins. ACTA ACUST UNITED AC 2006; 1769:41-8. [PMID: 17207870 DOI: 10.1016/j.bbaexp.2006.11.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2006] [Revised: 10/26/2006] [Accepted: 11/21/2006] [Indexed: 02/07/2023]
Abstract
Caudal-related homeobox transcription factors are involved in the definition of the anteroposterior axis and intestinal development. Recent reports indicate that dysregulation of CDX1 and CDX2, the human homologues of Drosophila caudal, are associated with several types of cancer. Very little is known, however, about the regulatory mechanisms that direct the caudal-related homeobox gene expression. In this study, we have identified the binding sites for bHLH-PAS proteins, referred to as CNS midline element (CME), in the 5'-flanking region of the Drosophila caudal gene. Analyses using transgenic flies carrying a caudal-lacZ fusion gene bearing a wild-type or mutant CME indicate that the CME sites are required for caudal gene expression in vivo. We also determined that the caudal promoter activity can be regulated by Trachealess (Trh)/Tango (Tgo) bHLH-PAS proteins, via the CME sites. Our results suggest that the Drosophila caudal gene is a target of the Trh/Tgo bHLH-PAS proteins.
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Affiliation(s)
- Yoon-Jeong Choi
- Department of Molecular Biology, College of Natural Science, Pusan National University, Busan 609-735, Korea
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Choi KH, Kim JS, Kim YS, Yoo MA, Chon TS. Pattern detection of movement behaviors in genotype variation of Drosophila melanogaster by using self-organizing map. ECOL INFORM 2006. [DOI: 10.1016/j.ecoinf.2005.12.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Bae MK, Kim SR, Wee HJ, Yoo MA, Oh SO, Baek SY, Kim BS, Kim JB, Sik-Yoon, Bae SK. Aspirin-induced blockade of NF-kB activity restrains up-regulation of glial fibrillary acidic protein in human astroglial cells. Vascul Pharmacol 2006. [DOI: 10.1016/j.vph.2006.08.368] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Bae SK, Kim SR, Kim JG, Kim JY, Koo TH, Jang HO, Yun I, Yoo MA, Bae MK. Hypoxic induction of human visfatin gene is directly mediated by hypoxia-inducible factor-1. FEBS Lett 2006; 580:4105-13. [PMID: 16828081 DOI: 10.1016/j.febslet.2006.06.052] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2006] [Revised: 06/19/2006] [Accepted: 06/23/2006] [Indexed: 12/27/2022]
Abstract
Visfatin has been originally identified as a growth factor for early stage B cells and recently known as an adipokine. Here, we report that hypoxia induces the visfatin mRNA and protein levels in MCF7 breast cancer cells. We also demonstrate that induction of visfatin gene is regulated by hypoxia-inducible factor-1alpha (HIF-1alpha). Moreover, 5'-flanking promoter region of human visfatin gene contains two functional HIF responsive elements (HREs), activating the expression of visfatin. Mutation of these HREs in the visfatin promoter abrogates activation of a luciferase reporter gene driven by visfatin promoter under hypoxia. Taken together, our results demonstrate that visfatin is a new hypoxia-inducible gene of which expression is stimulated through the interaction of HIF-1 with HRE sites in its promoter region.
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Affiliation(s)
- Soo-Kyung Bae
- College of Dentistry and Research Institute for Oral Biotechnology, Pusan National University, Pusan 602-739, South Korea
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Kang HJ, Lee SS, Lee CH, Shim JC, Shin HJ, Liu KH, Yoo MA, Shin JG. NEUROTOXIC PYRIDINIUM METABOLITES OF HALOPERIDOL ARE SUBSTRATES OF HUMAN ORGANIC CATION TRANSPORTERS. Drug Metab Dispos 2006; 34:1145-51. [PMID: 16624869 DOI: 10.1124/dmd.105.009126] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Two neurotoxic pyridinium metabolites of haloperidol, 4-(4-chlorophenyl)-1-[4-(4-fluorophenyl)-4-oxybutyl]pyridinium ion (HPP(+)) and 4-(4-(chlorophenyl)-1-4-(fluorophenyl)-4-hydroxybutyl-pyridinium (RHPP(+)), are formed in the liver and found in the brain. To understand how these neurotoxic pyridinium metabolites are distributed in the brain, HPP(+) and RHPP(+) were evaluated as substrates for human organic cation transporters (hOCTs). Both HPP(+) and RHPP(+) were accumulated in Caco-2 cells, and these accumulations were significantly inhibited by pretreatment with the hOCT inhibitors verapamil, cimetidine, phenoxybenzamine, and corticosterone. The contribution of each hOCT was evaluated based on measurements of the intracellular concentrations of haloperidol metabolites in Madin Darby canine kidney (MDCK) cells transfected with hOCT1, hOCT2, or hOCT3. HPP(+) accumulated in hOCT-overexpressing MDCK cells in a concentration-dependent manner, with estimated K(m) values of 0.99, 2.79, and 2.23 microM and V(max) values of 282.1, 256.1, and 400.2 pmol/min/microg protein for hOCT1, hOCT2, and hOCT3, respectively. RHPP(+) accumulated in hOCT1- and hOCT3-overexpressing MDCK cells, with estimated K(m) values of 5.15 and 8.21 microM and V(max) values of 1230.9 and 1348.6 pmol/min/microg protein for hOCT1 and hOCT3, respectively. On the other hand, RHPP(+) did not accumulate in the hOCT2-expressing MDCK cells. These results suggest that HPP(+) and RHPP(+) are substrates for hOCTs, with the exception of RHPP(+) for hOCT2. Thus, hOCTs seem to contribute to the disposition of these toxic metabolites in human subjects, although further in vivo studies are required to elucidate the involvement of hOCTs in the disposition of haloperidol pyridinium metabolites.
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Affiliation(s)
- Ho-Jin Kang
- Department of Pharmacology and PharmacoGenomics Research Center, Inje University College of Medicine, Busan 614-735, Korea
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Bae MK, Kim SR, Lee HJ, Wee HJ, Yoo MA, Ock Oh S, Baek SY, Kim BS, Kim JB, Bae SK. Aspirin-induced blockade of NF-kappaB activity restrains up-regulation of glial fibrillary acidic protein in human astroglial cells. Biochim Biophys Acta 2006; 1763:282-9. [PMID: 16516312 DOI: 10.1016/j.bbamcr.2006.01.005] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2005] [Revised: 01/12/2006] [Accepted: 01/12/2006] [Indexed: 01/04/2023]
Abstract
The marked induction of glial fibrillary acidic protein (GFAP) has been observed in astrocytes during neuropathological processes accompanying reactive gliosis; however, the precise molecular mechanism(s) underlying this GFAP induction remains poorly resolved. Therefore, in this study, we examined whether the change of nuclear factor-kappa B (NF-kappaB) activity can influence GFAP expression levels. Aspirin, widely used to prevent NF-kappaB activity, reduced the levels of GFAP mRNA and protein in human astroglial cells including human glioblastoma A172 cells and primary human brain astrocyte cells (HBAs). Furthermore, aspirin inhibited the effects of hypoxic injury on the up-regulation of GFAP expression in HBAs. We confirmed the repressive effect of aspirin on GFAP transcription by GFAP promoter-driven reporter assay and found that one NF-kappaB binding site conserved in the mouse and human GFAP gene promoters is critical for this effect. To further delineate whether NF-kappaB is directly involved in the regulation of GFAP gene expression, we transfected A172 cells with an expression vector encoding a super-repressor IkappaBalpha protein (IkappaBalpha-SR) to specifically inhibit NF-kappaB activity and found the marked reduction of GFAP protein levels in IkappaBalpha-SR-transfectant cells. Taken together, our results suggest that NF-kappaB may play pivotal roles in GFAP gene expression.
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Affiliation(s)
- Moon-Kyoung Bae
- Department of Oral Physiology, College of Dentistry, Pusan National University, Busan 602-739, South Korea
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Park JH, Sung IJ, Lee SW, Kim KW, Kim YS, Yoo MA. The zinc-finger transcription factor Snail downregulates proliferating cell nuclear antigen expression in colorectal carcinoma cells. Int J Oncol 2005. [DOI: 10.3892/ijo.26.6.1541] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
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Park JH, Sung IJ, Lee SW, Kim KW, Kim YS, Yoo MA. The zinc-finger transcription factor Snail downregulates proliferating cell nuclear antigen expression in colorectal carcinoma cells. Int J Oncol 2005; 26:1541-7. [PMID: 15870867] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/02/2023] Open
Abstract
The Snail family of zinc-finger protein is a transcription repressor that is involved in the development of vertebrate and invertebrate embryos as well as in tumor progression. This family leads to broad biological functions such as cell differentiation, cell motility, cell cycle regulation and apoptosis. However, the target genes of Snail remain little known. In this study, we found several potential Snail binding sequences in the 5'-flanking region of human PCNA gene. Cotransfection experiments showed that Snail reduces human PCNA gene promoter activity in colorectal carcinoma cell lines, HCT116 and Colo320HSR. Snail-reduced PCNA expression was detected in immunoblotting and immunochemistry. In BrdU incorporation experiment, Snail inhibited the BrdU incorporation. Electrophoretic mobility shift assays showed that Snail can bind to the potential Snail recognition sites in the human PCNA promoter. Taken together, our results suggest that Snail may have an inhibitory effect on cell proliferation through down-regulation of PCNA expression as a novel target.
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Affiliation(s)
- Jae-Hong Park
- Department of Molecular Biology, Pusan National University, Busan 609-735, Korea
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Kim KY, Lee JH, Park JH, Yoo MA, Kwak YG, Kim SO, Yoo SE, Hong KW. Anti-apoptotic action of (2S,3S,4R)-N"-cyano-N-(6-amino-3,4-dihydro-3-hydroxy-2-methyl-2-dimethoxymethyl-2H-benzopyran-4-yl)-N'-benzylguanidine (KR-31378) by suppression of the phosphatase and tensin homolog deleted from chromosome 10 phosphorylation and increased phosphorylation of casein kinase2/Akt/ cyclic AMP response element binding protein via maxi-K channel opening in neuronal cells. Eur J Pharmacol 2005; 497:267-77. [PMID: 15336944 DOI: 10.1016/j.ejphar.2004.06.058] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2004] [Revised: 05/17/2004] [Accepted: 06/29/2004] [Indexed: 10/26/2022]
Abstract
This study shows the signaling pathway by which (2S,3S,4R)-N"-cyano-N-(6-amino-3,4-dihydro-3-hydroxy-2-methyl-2-dimethoxymethyl-2H-benzopyran-4-yl)-N'-benzylguanidine (KR-31378) prevents tumor necrosis factor (TNF)-alpha-induced neuronal cell death. KR-31378 restored TNF-alpha-induced decreased cell viability of SK-N-SH. U87-MG cells (PTEN-null glioblastoma cell line) transfected with expression vectors for sense PTEN (phosphatase and tensin homolog deleted from chromosome 10) showed significantly decreased cell viability, which was restored by KR-31378. TNF-alpha-induced increased PTEN phosphorylation and decreased phosphorylation of Akt/cyclic AMP response element-binding protein (CREB) in SK-N-SH cells were concentration-dependently reversed by KR-31378, those of which were antagonized by iberiotoxin, a maxi-K channel blocker. TNF-alpha and apigenin, a casein kinase2 (CK2) inhibitor, showed decreased CK2 phosphorylation and increased PTEN phosphorylation, which were reversed by KR-31378. KR-31378 increased K(+) currents by activating the maxi-K channels in SK-N-SH cells, with suppression of TNF-alpha-induced increase in cytosolic Ca(2+) and elevation of suppressed mitochondrial membrane potential, all of which were antagonized by iberiotoxin. It is suggested that increase in cell viability by KR-31378 is ascribed to the maxi-K channel opening-coupled upregulation of CK2/Akt/CREB phosphorylation and downregulation of PTEN phosphorylation in association with increased Bcl-2 and decreased Bax levels.
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Affiliation(s)
- Ki Young Kim
- Medicinal Science Division, Korea Research Institute of Chemical Technology, Yuseong, Daejeon 305-600, Korea
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Kim JH, Lee SY, Oh SY, Han SI, Park HG, Yoo MA, Kang HS. Methyl jasmonate induces apoptosis through induction of Bax/Bcl-XS and activation of caspase-3 via ROS production in A549 cells. Oncol Rep 2004; 12:1233-8. [PMID: 15547743] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/01/2023] Open
Abstract
Jasmonates are plant lipid derivatives, similar to mammalian eicosanoid, that play a critical role(s) in plant defenses against herbivores and pathogens through up-regulating the expression of defense-related genes. Recently, jasmonates were shown to induce cell cycle arrest or apoptosis in human leukemia, prostate and breast cancer cells, but not in normal lymphocytes, suggesting that the chemicals can be used as a novel class of anti-cancer drugs. In the present study, we examined the molecular mechanism that contributes to methyl jasmonate-induced apoptosis. Herein we show that methyl jasmonate induces apoptosis through induction of Bax/Bcl-XS and activation of caspase-3 via reactive oxygen species production in A549 human lung adenocarcinoma cells.
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Affiliation(s)
- Ji Hye Kim
- Department of Molecular Biology, College of Natural Sciences, Pusan National University, Pusan 609-735, Korea
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Kim J, Lee S, Oh S, Han S, Park H, Yoo MA, Kang H. Methyl jasmonate induces apoptosis through induction of Bax/Bcl-Xs and activation of caspase-3 via ROS production in A549 cells. Oncol Rep 2004. [DOI: 10.3892/or.12.6.1233] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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Kwon E, Hayashi Y, Otsuki K, Hirose F, Nishida Y, Yoo MA, Yamaguchi M. Armadillo/Pangolin regulates PCNA and DREF promoter activities. ACTA ACUST UNITED AC 2004; 1679:256-62. [PMID: 15358517 DOI: 10.1016/j.bbaexp.2004.07.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2004] [Revised: 07/07/2004] [Accepted: 07/19/2004] [Indexed: 10/26/2022]
Abstract
Here we show that Armadillo and Pangolin (dTCF), downstream effectors of the Wingless (Wg) signal transduction pathway, activate transcription of the important DNA replication-related genes encoding Drosophila proliferating cell nuclear antigen (PCNA) and DNA replication-related element-binding factor (DREF). By transient luciferase expression assays and band mobility shift assays, we demonstrated the PCNA gene to be a direct target gene for the Armadillo/Pangolin complex. Using a GAL4-UAS system, stimulation of the PCNA gene by Armadillo/Pangolin was confirmed in adult females. From the published reports of an inhibitory role, we expected that Drosophila CREB-binding protein (dCBP) would interfere with activation. However, effects were only observed with the DREF but not the PCNA gene. In the latter case, as in mammals, dCBP could potentiate Armadillo-mediated activation. These results suggest that first, PCNA and DREF genes are targets of the Armadillo/Pangolin complex and second, dCBP modulates Wg signaling in a gene-specific manner.
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Affiliation(s)
- Eunjeong Kwon
- Division of Biochemistry, Aichi Cancer Center Research Institute, Chikusa, Nagoya 464-8681, Japan
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Choi YJ, Choi TY, Yamaguchi M, Matsukage A, Kim YS, Yoo MA. Transcriptional regulation of the Drosophila caudal homeobox gene by DRE/DREF. Nucleic Acids Res 2004; 32:3734-42. [PMID: 15254275 PMCID: PMC484175 DOI: 10.1093/nar/gkh688] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The caudal-related homeobox transcription factors are required for the normal development and differentiation of intestinal cells. Recent reports indicate that misregulation of homeotic gene expression is associated with gastrointestinal cancer in mammals. However, the molecular mechanisms that regulate expression of the caudal-related homeobox genes are poorly understood. In this study, we have identified a DNA replication-related element (DRE) in the 5' flanking region of the Drosophila caudal gene. Gel-mobility shift analysis reveals that three of the four DRE-related sequences in the caudal 5'-flanking region are recognized by the DRE-binding factor (DREF). Deletion and site-directed mutagenesis of these DRE sites results in a considerable reduction in caudal gene promoter activity. Analyses with transgenic flies carrying a caudal-lacZ fusion gene bearing wild-type or mutant DRE sites indicate that the DRE sites are required for caudal expression in vivo. These findings indicate that DRE/DREF is a key regulator of Drosophila caudal homeobox gene expression and suggest that DREs and DREF contribute to intestinal development by regulating caudal gene expression.
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Affiliation(s)
- Yoon-Jeong Choi
- Department of Molecular Biology, College of Natural Science and Research Institute of Genetic Engineering, Pusan National University, Busan 609-735, Korea
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Choi TY, Park SY, Kang HS, Cheong JH, Kim HD, Lee BL, Hirose F, Yamaguchi M, Yoo MA. Redox regulation of DNA binding activity of DREF (DNA replication-related element binding factor) in Drosophila. Biochem J 2004; 378:833-8. [PMID: 14651474 PMCID: PMC1224010 DOI: 10.1042/bj20031601] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2003] [Accepted: 12/02/2003] [Indexed: 11/17/2022]
Abstract
DREF [DRE (DNA replication-related element) binding factor] is an 80 kDa polypeptide homodimer which plays an important role in regulating cell proliferation-related genes. Both DNA binding and dimer formation activities are associated with residues 16-115 of the N-terminal region. However, the mechanisms by which DREF dimerization and DNA binding are regulated remain unknown. Here, we report that the DNA binding activity of DREF is regulated by a redox mechanism, and that the cysteine residues are involved in this regulation. Electrophoretic mobility shift analysis using Drosophila Kc cell extracts or recombinant DREF proteins indicated that the DNA binding domain is sufficient for redox regulation. Site-directed mutagenesis and transient transfection assays showed that Cys59 and/or Cys62 are critical both for DNA binding and for redox regulation, whereas Cys91 is dispensable. In addition, experiments using Kc cells indicated that the DNA binding activity and function of DREF are affected by the intracellular redox state. These findings give insight into the exact nature of DREF function in the regulation of target genes by the intracellular redox state.
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Affiliation(s)
- Tae-Yeong Choi
- Department of Molecular Biology, College of Natural Science, Pusan National University, Busan 609-735, Korea
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Abstract
Reactive oxygen species (ROS) cause oxidative stress and aging. The catalase gene is a key component of the cellular antioxidant defense network. However, the molecular mechanisms that regulate catalase gene expression are poorly understood. In this study, we have identified a DNA replication-related element (DRE; 5'-TATCGATA) in the 5'-flanking region of the Drosophila catalase gene. Gel mobility shift assays revealed that a previously identified factor called DREF (DRE- binding factor) binds to the DRE sequence in the Drosophila catalase gene. We used site-directed mutagenesis and in vitro transient transfection assays to establish that expression of the catalase gene is regulated by DREF through the DRE site. To explore the role of DRE/DREF in vivo, we established transgenic flies carrying a catalase-lacZ fusion gene with or without mutation in the DRE. The beta-galactosidase expression patterns of these reporter transgenic lines demonstrated that the catalase gene is upregulated by DREF through the DRE sequence. In addition, we observed suppression of the ectopic DREF-induced rough eye phenotype by a catalase amorphic Cat(n1) allele, indicating that DREF activity is modulated by the intracellular redox state. These results indicate that the DRE/DREF system is a key regulator of catalase gene expression and provide evidence of cross-talk between the DRE/DREF system and the antioxidant defense system.
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Affiliation(s)
- So Young Park
- Department of Molecular Biology, Pusan National University, Busan 609-735, Korea
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Ryu JH, Nam KB, Oh CT, Nam HJ, Kim SH, Yoon JH, Seong JK, Yoo MA, Jang IH, Brey PT, Lee WJ. The homeobox gene Caudal regulates constitutive local expression of antimicrobial peptide genes in Drosophila epithelia. Mol Cell Biol 2004; 24:172-85. [PMID: 14673153 PMCID: PMC303351 DOI: 10.1128/mcb.24.1.172-185.2004] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
In Drosophila melanogaster, although the NF-kappaB transcription factors play a pivotal role in the inducible expression of innate immune genes, such as antimicrobial peptide genes, the exact regulatory mechanism of the tissue-specific constitutive expression of these genes in barrier epithelia is largely unknown. Here, we show that the Drosophila homeobox gene product Caudal functions as the innate immune transcription modulator that is responsible for the constitutive local expression of antimicrobial peptides cecropin and drosomycin in a tissue-specific manner. These results suggest that certain epithelial tissues have evolved a unique constitutive innate immune strategy by recruiting a developmental "master control" gene.
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Affiliation(s)
- Ji-Hwan Ryu
- Division of Molecular Life Science and Center for Cell Signaling Research, Ewha Womans University, Seoul, South Korea
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Choi YH, Kang HS, Yoo MA. Suppression of human prostate cancer cell growth by beta-lapachone via down-regulation of pRB phosphorylation and induction of Cdk inhibitor p21(WAF1/CIP1). J Biochem Mol Biol 2003; 36:223-9. [PMID: 12689523 DOI: 10.5483/bmbrep.2003.36.2.223] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The product of a tree (Tabebuia avellanedae) from South America, beta-lapachone, is known to exhibit various pharmacological properties, the mechanisms of which are poorly understood. The aim of the present study was to further elucidate the possible mechanisms by which beta-lapachone exerts its anti-proliferative action in cultured human prostate cancer cells. We observed that the proliferation-inhibitory effect of beta-lapachone was due to the induction of apoptosis, which was confirmed by observing the morphological changes and cleavage of the poly(ADP-ribose) polymerase protein. A DNA flow cytometric analysis also revealed that beta-lapachone arrested the cell cycle progression at the G1 phase. The effects were associated with the down-regulation of the phosphorylation of the retinoblastoma protein (pRB) as well as the enhanced binding of pRB and the transcription factor E2F-1. Also, beta-lapachone suppressed the cyclin-dependent kinases (Cdks) and cyclin E-associated kinase activity without changing their expressions. Furthermore, this compound induced the levels of the Cdk inhibitor p21(WAF1/CIP1) expression in a p53-independent manner, and the p21 proteins that were induced by beta-lapachone were associated with Cdk2. beta-lapachone also activated the reporter construct of a p21 promoter. Overall, our results demonstrate a combined mechanism that involves the inhibition of pRB phosphorylation and induction of p21 as targets for beta-lapachone. This may explain some of its anticancer effects.
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Affiliation(s)
- Yung Hyun Choi
- Department of Biochemistry, College of Oriental Medicine, Dong-Eui University and Research Center for Oriental Medicine, Pusan 614-052, Korea.
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Hwang MS, Kim YS, Choi NH, Park JH, Oh EJ, Kwon EJ, Yamaguchi M, Yoo MA. The caudal homeodomain protein activates Drosophila E2F gene expression. Nucleic Acids Res 2002; 30:5029-35. [PMID: 12466526 PMCID: PMC137955 DOI: 10.1093/nar/gkf640] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The Drosophila caudal homeobox gene is required for definition of the anteroposterior axis and for gut development, and CDX1 and CDX2, human homologs, play crucial roles in the regulation of cell proliferation and differentiation in the intestine. Most studies have indicated tumor suppressor functions of Cdx2, with inhibition of proliferation, while the effects of Cdx1 are more controversial. The influence of Drosophila Caudal on cell proliferation is unknown. In this study, we found three potential Caudal binding sequences in the 5'-flanking region of the Drosophila E2F (DE2F) gene and showed by transient transfection assays that they are involved in Caudal transactivation of the dE2F gene promoter. Analyses with transgenic flies carrying an E2F-lacZ fusion gene, with and without mutation in the Caudal binding site, indicated that the Caudal binding sites are required for expression of dE2F in living flies. Caudal-induced E2F expression was also confirmed with a GAL4-UAS system in living flies. In addition, ectopic expression of Caudal with heat-shock promotion induced melanotic tumors in larvae. These results suggest that Caudal is involved in regulation of proliferation through transactivation of the E2F gene in Drosophila.
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Affiliation(s)
- Mi-Sun Hwang
- Department of Molecular Biology, Pusan National University, Pusan 609-735, Korea
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