• Genomics & Informatics
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• 제21권2호
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• pp.23.1-23.9
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• 2023

The mammalian sirtuin family, consisting of SIRT1-SIRT7, plays a vital role in various biological processes, including cancer, diabetes, neurodegeneration, cardiovascular disease, cellular metabolism, and cellular homeostasis maintenance. Due to their involvement in these biological processes, modulating sirtuin activity seems promising to impact immuneand aging-related diseases, as well as cancer pathways. However, more understanding is required regarding the safety and efficacy of sirtuin-targeted therapies due to the complex regulatory mechanisms that govern their activity, particularly in the context of multiple targets. In this study, the interaction landscape of the sirtuin family was analyzed using a systems biology approach. A sirtuin protein-protein interaction network was built using the Cytoscape platform and analyzed using the NetworkAnalyzer and stringApp plugins. The result revealed the sirtuin family's association with numerous proteins that play diverse roles, suggesting a complex interplay between sirtuins and other proteins. Based on network topological and functional analysis, SIRT1 was identified as the most prominent among sirtuin family members, demonstrating that 25 of its protein partners are involved in cancer, 22 in innate immune response, and 29 in aging, with some being linked to a combination of two or more pathways. This study lays the foundation for the development of novel therapies that can target sirtuins with precision and efficacy. By illustrating the various interactions among the proteins in the sirtuin family, we have revealed the multifaceted roles of SIRT1 and provided a framework for their possible roles to be precisely understood, manipulated, and translated into therapeutics in the future.

• 대한본초학회지
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• 제37권2호
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• pp.1-11
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• 2022

Objectives : Although the anti-obesity effect of Schizandrae Fructus water extract has been demonstrated, its underlying mechanism is still unclear. Therefore, we aimed to evaluate the anti-obesity effect of Schizandrae Fructus water extract through the p-AMP-activated protein kinase (p-AMPK), sirtuin1 (Sirt1), and peroxisome proliferator-activated receptor-gamma coactivator 1α (PGC-1α) signaling in 60% high-fat diet (HFD)-induced obese mouse model. Methods : Male C57BL/6 mice were divided into four groups. The Normal group was fed a normal diet and the obese groups were fed 60% HFD. Except for the Control group, the GG group was supplemented with 0.5% Garcinia gummigutta and the SCW group was supplemented with 0.5% Schizandrae Fructus water extract. After 6 weeks, obesity-related biomarkers in serum were measured and the expressions of protein for lipid-related factors in liver tissue were analyzed by western blot. Results : Treatment with SCW significantly down-regulated body weight compared to the Control group. SCW down-regulated levels of triglyceride and total cholesterol in serum and significantly increased p-AMPK, Sirt1, and PGC-1α in liver tissue. In addition, the expressions of fatty acid oxidation-related proteins such as peroxisome proliferator-activated receptor α (PPARα), carnitine palmitoyltransferase 1A (CPT-1A), uncoupling protein 1 (UCP1), and uncoupling protein 3 (UCP3) were significantly up-regulated. However, fatty acid synthesis-related proteins including sterol regulatory element-binding protein-1 (SREBP-1), phospho-Acetyl-CoA Carboxylase (p-ACC), and fatty acid synthase (FAS) were significantly down-regulated. Conclusions : Taken together, SCW treatment showed anti-obesity effect by regulating both fatty acid oxidation-related and fatty acid synthesis-related proteins through AMPK/Sirt1/PGC-1α signaling in 60% HFD-induced obese mice.

• Journal of Ginseng Research
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• 제46권6호
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• pp.759-770
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• 2022

Background: Aerobic cellular respiration provides chemical energy, adenosine triphosphate (ATP), to maintain multiple cellular functions. Sirtuin 1 (SIRT1) can deacetylate peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PGC-1α) to promote mitochondrial biosynthesis. Targeting energy metabolism is a potential strategy for the prevention and treatment of various diseases, such as cardiac and neurological disorders. Ginsenosides, one of the major bioactive constituents of Panax ginseng, have been extensively used due to their diverse beneficial effects on healthy subjects and patients with different diseases. However, the underlying molecular mechanisms of total ginsenosides (GS) on energy metabolism remain unclear. Methods: In this study, oxygen consumption rate, ATP production, mitochondrial biosynthesis, glucose metabolism, and SIRT1-PGC-1α pathways in untreated and GS-treated different cells, fly, and mouse models were investigated. Results: GS pretreatment enhanced mitochondrial respiration capacity and ATP production in aerobic respiration-dominated cardiomyocytes and neurons, and promoted tricarboxylic acid metabolism in cardiomyocytes. Moreover, GS clearly enhanced NAD⁺-dependent SIRT1 activation to increase mitochondrial biosynthesis in cardiomyocytes and neurons, which was completely abrogated by nicotinamide. Importantly, ginsenoside monomers, such as Rg1, Re, Rf, Rb1, Rc, Rh1, Rb2, and Rb3, were found to activate SIRT1 and promote energy metabolism. Conclusion: This study may provide new insights into the extensive application of ginseng for cardiac and neurological protection in healthy subjects and patients.

• International Journal of Oral Biology
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• 제35권2호
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• pp.61-67
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• 2010

Selenoprotein S (SelS) is widely expressed in diverse tissues where it localizes in the plasma membrane and endoplasmic reticulum. We studied the potential function of SelS in erythrocyte differentiation using K562 cells stably over-expressing SelS wild-type (WT) or one of two SelS point mutants, $U_{188}S$ or $U_{188}C$. We found that in the K562 cells treated with $1\;{\mu}M$ Ara-C, SelS gradually declined over five days of treatment. On day 4, intracellular ROS levels were higher in cells expressing SelS-WT than in those expressing a SelS mutant. Moreover, the cell cycle patterns in cells expressing SelS-WT or $U_{188}C$ were similar to the controls. The expression and activation of SIRT1 were also reduced during K562 differentiation. Cells expressing SelS-WT showed elevated SIRT1 expression and activation (phosphorylation), as well as higher levels of FoxO3a expression. SIRT1 activation was diminished slightly in cells expressing SelS-WT after treatment with the ROS scavenger NAC (12 mM), but not in those expressing a SelS mutant. After four days of Ara-C treatment, SelS-WT-expressing cells showed elevated transcription of $\beta$-globin, $\gamma$-globin, $\varepsilon$-globin, GATA-1 and zfpm-1, whereas cells expressing a SelS mutant did not. These results suggest that the suppression of SelS acts as a trigger for proerythrocyte differentiation via the ROS-mediated downregulation of SIRT1.

• BMB Reports
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• 제46권9호
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• pp.429-438
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• 2013

Aging is the strongest risk factor for cancer development, suggesting that molecular crosstalks between aging and tumorigenesis exist in many cellular pathways. Recently, Sirtuins (Sirt1-7), the mammalian homologues of aging-related $sir2{\alpha}$ in yeast, have been shown to modulate several major cellular pathways, such as DNA repair, inflammation, metabolism, cell death, and proliferation in response to diverse stresses, and may serve as a possible molecular link between aging and tumorignenesis. In addition, growing evidence suggests that sirtuins are directly implicated in the development of cancer, and they can act as either a tumor suppressor or promoter, depending on the cellular context and tumor types. While the functions of Sirt1 in tumorigenesis have been reported and reviewed in many studies, the connection between sirtuins 2-7 and the development of cancer is less established. Thus, this review will present the recent updates on the emerging roles of Sirt2-7 members in carcinogenesis.

• 생명과학회지
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• 제20권3호
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• pp.444-452
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• 2010

본 연구의 목적은 PS-2 (N141I) 알츠하이머 형질전환 모델 생쥐를 대상으로 트레드밀 운동이 뇌의 세포질과 미토콘드리아의 $A{\beta}$-42, cytochrome c, SOD-1, 2 and Sirt-3 단백질 발현에 미치는 효과를 알아보는데 있다. 우선 알츠하이머 형질전환 생쥐를 Non-Tg-sedentary (n=5), Non-Tg-treadmill exercise (n=5) 집단과 Tg-sedentary (n=5), Tg-treadmill exercise (n=5) 집단으로 구분하고 트레드밀 운동을 통한 신경보호 효과를 검증하기 위해 Tg와 Non-Tg집단에 12주간 트레드밀 운동을 수행한 후 인지능력을 살펴보고 뇌의 세포질과 미토콘드리아의 $A{\beta}$-42, cytochrome c, anti-oxidant enzymes (SOD-1, SOD-2)와 Sirt-3 단백질을 분석하였다. 먼저 트레드밀운동은 Tg 집단에서 인지능력의 개선을 나타냈으며 미토콘드리아의 $A{\beta}$-42와 세포질의 cytochrome c 단백질의 감소와 항산화 효소인 SOD-1, SOD-2를 유의하게 증가시켰다. 게다가 트레드밀 운동은 모든 집단에서 Sirt-3 단백질의 발현을 증가시켰다. 따라서 트레드밀 운동은 인지능력의 향상과 세포 내 스트레스를 유발하는 $A{\beta}$-42를 억제시켜 알츠하이머 질환을 개선시킬 수 있는 효과적인 방법이라고 생각된다.

• 대한한방내과학회지
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• 제35권1호
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• pp.70-78
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• 2014

Objectives : Hoechunyanggyeok-san (HYS) is a traditional herbal medicine, which has been clinically used for treating febrile and inflammatory diseases. HYS has been reported to be a useful treatment for diabetes, atherosclerosis and hyperlipidemia in the type 1 diabetic model. However, the mechanism of the effects of HYS against hyperglycemia and hyperlipidemia is poorly understood. In the present study, we investigated the underlying mechanism of ameliorative effect of HYS on hyperglycemia and hyperlipidemia in vivo. Methods : HYS (10, 50 mg/kg/day, p.o.) was administered every day for 2 weeks to db/db mice and its effect was compared with vehicle-treated db/db mice. To confirm serum glucose and triglyceride (TG) changes, serological testing was performed. The levels of sterol regulatory element-binding protein-1 (SREBP-1) activity and Sirtuin1 (SIRT1), AMP-activated protein kinase (AMPK), and acetyl-CoA carboxylase ${\alpha}$ ($ACC{\alpha}$) expression were analyzed by western blot analysis. Results : The administration of HYS significantly decreased the elevated serum glucose and TG in db/db mice. HYS administration increased the levels of SIRT1 and AMPK expression compared with the vehicle-treated group. Moreover, HYS treatment significantly inhibited SREBP-1 activity and $ACC{\alpha}$ expression in the liver, while the vehicle-treated group exhibited their increase. Conclusions : In conclusion, HYS is suggested to have an improvement effect on hyperglycemia and hyperlipidemia by activating the SIRT1/AMPK signaling pathway and inhibiting SREBP-1.

• Toxicological Research
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• 제30권1호
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• pp.19-25
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• 2014

Licochalcone (LC), a major phenolic retrochalcone from licorice, has anti-inflammatory activity. This study investigated the effects of licochalcone A (LCA) and licochalcone E (LCE) on Liver X receptor-${\alpha}$ ($LXR{\alpha}$)-mediated lipogenic gene expression and the molecular mechanisms underlying those effects. LCA and LCE antagonized the ability of $LXR{\alpha}$ agonists (T0901317 or GW3965) to increase sterol regulatory element binding protein-1c (SREBP-1c) expression and thereby inhibited target gene expression (e.g., FAS and ACC) in HepG2 cells. Moreover, treatment with LCA and LCE impaired $LXR{\alpha}/RXR{\alpha}$-induced CYP7A1-LXRE-luciferase (CYP7A1) transactivation. The AMPK-Sirt1 signaling pathway is an important regulator of energy metabolism and, therefore, a potential therapeutic target for metabolic diseases, including hepatic steatosis. We found here that LCE increased AMPK phosphorylation and Sirt1 expression. We conclude that LC inhibits SREBP-1c-mediated hepatic lipogenesis via activation of the AMPK/Sirt1 signaling pathway.

• Molecules and Cells
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• 제45권3호
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• pp.112-121
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• 2022

Calorie restriction (CR) and the activation of autophagy extend healthspan by delaying the onset of age-associated diseases in most living organisms. Because protein kinase CK2 (CK2) downregulation induces cellular senescence and nematode aging, we investigated CK2's role in CR and autophagy. This study indicated that CR upregulated CK2's expression, thereby causing SIRT1 and AMP-activated protein kinase (AMPK) activation. CK2α overexpression, including antisense inhibitors of miR-186, miR-216b, miR-337-3p, and miR-760, stimulated autophagy initiation and nucleation markers (increase in ATG5, ATG7, LC3BII, beclin-1, and Ulk1, and decrease in SQSTM1/p62). The SIRT1 deacetylase, AKT, mammalian target of rapamycin (mTOR), AMPK, and forkhead homeobox type O (FoxO) 3a were involved in CK2-mediated autophagy. The treatment with the AKT inhibitor triciribine, the AMPK activator AICAR, or the SIRT1 activator resveratrol rescued a reduction in the expression of lgg-1 (the Caenorhabditis elegans ortholog of LC3B), bec1 (the C. elegans ortholog of beclin-1), and unc-51 (the C. elegans ortholog of Ulk1), mediated by kin-10 (the C. elegans ortholog of CK2β) knockdown in nematodes. Thus, this study indicated that CK2 acted as a positive regulator in CR and autophagy, thereby suggesting that these four miRs' antisense inhibitors can be used as CR mimetics or autophagy inducers.

• Toxicological Research
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• 제34권1호
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• pp.23-29
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• 2018

Ethanol-induced fat accumulation, the earliest and most common response of the liver to ethanol exposure, may be involved in the pathogenesis of liver diseases. Isoliquiritigenin (ISL), an important constituent of Glycyrrhizae Radix, is a chalcone derivative that exhibits antioxidant, anti-inflammatory, and phytoestrogenic activities. However, the effect of ISL treatment on lipid accumulation in hepatocytes and alcoholic hepatitis remains unclear. Therefore, we evaluated the effect and underlying mechanism of ISL on ethanol-induced hepatic steatosis by treating AML-12 cells with 200 mM ethanol and/or ISL ($0{\sim}50{\mu}M$) for 72 hr. Lipid accumulation was assayed by oil red O staining, and the expression of sirtuin1 (SIRT1), sterol regulatory element-binding protein-1c (SREBP-1c), AMP-activated protein kinase (AMPK), and peroxisome proliferator-activated receptor alpha ($PPAR{\alpha}$) was studied by western blotting. Our results indicated that ISL treatment upregulated SIRT1 expression and downregulated SREBP-1c expression in ethanol-treated cells. Similarly, oil red O staining revealed a decrease in ethanol-induced fat accumulation upon co-treatment of ethanol-treated cells with 10, 20, and $50{\mu}M$ of ISL. These findings suggest that ISL can reduce ethanol induced-hepatic lipogenesis by activating the SIRT1-AMPK pathway and thus improve lipid metabolism in alcoholic fatty livers.