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Kim HS, Chung SS, Lee RA, Noh GT. Splenic flexure mobilization for sigmoid colon cancer with da Vinci SP ® surgical system: a video vignette. Tech Coloproctol 2023; 28:1. [PMID: 38063907 DOI: 10.1007/s10151-023-02876-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Accepted: 11/04/2023] [Indexed: 12/18/2023]
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Kim HS, Noh GT, Chung SS, Lee RA. Long-term oncological outcomes of robotic versus laparoscopic approaches for right colon cancer: a systematic review and meta-analysis. Tech Coloproctol 2023; 27:1183-1189. [PMID: 37783821 DOI: 10.1007/s10151-023-02857-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Accepted: 08/09/2023] [Indexed: 10/04/2023]
Abstract
PURPOSE The short-term outcomes of robotic right hemicolectomy for right colon cancer have been extensively studied in comparison to conventional laparoscopic right hemicolectomy. However, the long-term oncological outcomes of the two approaches have not been investigated, except in single-center retrospective studies. Therefore, this meta-analysis aimed to investigate the long-term oncological outcomes of robotic right hemicolectomy compared with those of laparoscopic right hemicolectomy for right colon cancer. METHODS We searched PubMed, EMBASE, and Cochrane Library for studies comparing robotic right hemicolectomy with conventional laparoscopic right hemicolectomy for right colon cancer from the date of database inception to August 2022. For survival data extraction, hazard ratios (HRs) with 95% confidence intervals (CI) were calculated using random- or fixed-effects models from the Kaplan-Meier survival curves in the included studies. All calculations and statistical tests were performed using Review Manager software, version 5.4. RESULTS A total of 523 patients (robotic right hemicolectomy, 230; laparoscopic right hemicolectomy, 293) from five studies were included in this meta-analysis. There were no significant differences in patient characteristics between the two groups. In terms of pathological characteristics, TNM stage was not different and revealed no differences in the number of harvested lymph nodes even though a larger number of lymph nodes were harvested in the robotic group in one study. Pooled analyses demonstrated no significant difference in disease-free survival (HR 0.72, 95% CI 0.46-1.13, p = 0.15) and overall survival (HR 0.73, 95% CI 0.48-1.13, p = 0.16) between robotic and laparoscopic right hemicolectomy for right colon cancer. CONCLUSION Robotic right hemicolectomy for right colon cancer is comparable with conventional laparoscopic right hemicolectomy in terms of long-term oncological survival. More prospective, multicenter, randomized trials are necessary to determine the oncologic safety of robotic right hemicolectomy.
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Lee JS, Min JE, Choe HJ, Park KS, Chung SS. SUMO-specific protease 2 regulates lipid droplet size through ERRα-mediated CIDEA expression in adipocytes. Biochem Biophys Res Commun 2023; 681:29-35. [PMID: 37748256 DOI: 10.1016/j.bbrc.2023.09.052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Revised: 09/16/2023] [Accepted: 09/19/2023] [Indexed: 09/27/2023]
Abstract
Lipid droplets are not only lipid storage sites but also are closely related to lipid metabolism. Lipid droplet growth increases lipid storage capacity and suppresses lipolysis via lipase associated with the lipid droplet surface. The cell death-inducing DFF45-like effector (CIDE) family of proteins mediates lipid droplet fusion, which mainly contributes to lipid droplet growth. We previously demonstrated small ubiquitin-like modifier (SUMO)-specific protease 2 (SENP2) plays important roles in lipid metabolism and induction/maintenance of adipogenesis. In this study, we determined whether SENP2 regulates lipid droplet size in adipocytes. Overexpression of SENP2 increased lipid droplet size in differentiated 3T3-L1 adipocytes and facilitated CIDEA transcription. We found SENP2 increased CIDEA expression mainly through desumoylation of estrogen-related receptor α (ERRα), which acted in coordination with peroxisome proliferator-activated receptor γ-coactivator α. In addition, palmitate treatment increased SENP2 and CIDEA mRNA levels. Specific small interfering RNA-mediated knockdown of SENP2, as well as ERRα knockdown, eliminated palmitate-induced CIDEA expression. These results suggest SENP2 enhances CIDEA expression by modulating ERRα when SENP2 is upregulated, such as after palmitate treatment, to increase lipid droplet size in adipocytes.
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Kim HS, Oh BY, Cheong C, Park MH, Chung SS, Lee RA, Kim KH, Noh GT. Single-incision robotic colorectal surgery with the da Vinci SP® surgical system: initial results of 50 cases. Tech Coloproctol 2023; 27:589-599. [PMID: 36971849 DOI: 10.1007/s10151-023-02791-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Accepted: 03/14/2023] [Indexed: 06/06/2023]
Abstract
PURPOSE The da Vinci SP® (dVSP) surgical system (Intuitive Surgical, Sunnyvale, CA, USA), a robotic platform designed for single-incision surgery, overcame the need for multiple ports in traditional robotic surgery and issues including triangulation and retraction in single-incision laparoscopic surgery. However, previous studies only included case reports or series with small sample sizes. The aim of this study was to assess the safety and performance of the dVSP surgical system and its instruments and accessories for colorectal procedures. METHODS The medical records of patients who had surgery with the dVSP from March 2019 to September 2021 at Ewha Womans University Seoul Hospital were investigated. The pathologic and follow-up data of patients who had malignant tumors were analyzed separately to evaluate oncological safety. RESULTS Fifty patients (26 male and 24 female) with a median age of 59 years (interquartile range 52.5-63.0 years) were enrolled. The procedures included low anterior resection with total mesorectal excision (n = 16), sigmoid colectomy with complete mesocolic excision and central vessel ligation (CME + CVL) (n = 14), right colectomy with CME + CVL (n = 9), left colectomy with CME + CVL (n = 4), right colectomy (n = 6), and sigmoid colectomy (n = 1). Operative time significantly decreased after 25 cases (early phase vs. late phase; operative time 295.0 min vs. 250.0 min, p = 0.015; docking time 16.0 min vs. 12.0 min, p = 0.001; console time 212.0 min vs. 190.0 min, p = 0.019). Planned procedures were successfully completed in all patients. Postoperative outcomes were acceptable with only six cases of mild adverse events through a 3-month follow-up. No local recurrence and only one case of systemic recurrence occurred within 1 year postoperatively. CONCLUSIONS This study demonstrated the surgical and oncological safety and feasibility of dVSP, which may be a novel surgical platform for colorectal surgery.
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Lee SA, Kim S, Kim SY, Park JY, Nan J, Park HS, Lee H, Lee YD, Lee H, Kang S, Jung HS, Chung SS, Park KS. Direct Differentiation of Bone Marrow Mononucleated Cells Into Insulin-Producing Cells Using 4 Specific Soluble Factors. Stem Cells Transl Med 2023:szad035. [PMID: 37350544 DOI: 10.1093/stcltm/szad035] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Accepted: 05/12/2023] [Indexed: 06/24/2023] Open
Abstract
Bone marrow-derived stem cells are self-renewing and multipotent adult stem cells that differentiate into several types of cells. Here, we investigated a unique combination of 4 differentiation-inducing factors (DIFs), including putrescine (Put), glucosamine (GlcN), nicotinamide, and BP-1-102, to develop a differentiation method for inducing mature insulin-producing cells (IPCs) and apply this method to bone marrow mononucleated cells (BMNCs) isolated from mice. BMNCs, primed with the 4 soluble DIFs, were differentiated into functional IPCs. BMNCs cultured under the defined conditions synergistically expressed multiple genes, including those for PDX1, NKX6.1, MAFA, NEUROG3, GLUT2, and insulin, related to pancreatic beta cell development and function. They produced insulin/C-peptide and PDX1, as assessed using immunofluorescence and flow cytometry. The induced cells secreted insulin in a glucose-responsive manner, similar to normal pancreatic beta cells. Grafting BMNC-derived IPCs under kidney capsules of mice with streptozotocin (STZ)-induced diabetes alleviated hyperglycemia by lowering blood glucose levels, enhancing glucose tolerance, and improving glucose-stimulated insulin secretion. Insulin- and PDX1-expressing cells were observed in the IPC-bearing graft sections of nephrectomized mice. Therefore, this study provides a simple protocol for BMNC differentiation, which can be a novel approach for cell-based therapy in diabetes mellitus.
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Kim PC, Lee JS, Chung SS, Park KS. Role of SUMO-Specific Protease 2 in Leptin-Induced Fatty Acid Metabolism in White Adipocytes. Diabetes Metab J 2023:dmj.2022.0156. [PMID: 36872063 DOI: 10.4093/dmj.2022.0156] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Accepted: 08/08/2022] [Indexed: 03/07/2023] Open
Abstract
BACKGROUND Leptin is a 16-kDa fat-derived hormone with a primary role in controlling adipose tissue levels. Leptin increases fatty acid oxidation (FAO) acutely through adenosine monophosphate-activated protein kinase (AMPK) and on delay through the SUMO-specific protease 2 (SENP2)-peroxisome proliferator-activated receptor δ/γ (PPARδ/γ) pathway in skeletal muscle. Leptin also directly increases FAO and decreases lipogenesis in adipocytes; however, the mechanism behind these effects remains unknown. Here, we investigated the role of SENP2 in the regulation of fatty acid metabolism by leptin in adipocytes and white adipose tissues. METHODS The effects of leptin mediated by SENP2 on fatty acid metabolism were tested by siRNA-mediated knockdown in 3T3-L1 adipocytes. The role of SENP2 was confirmed in vivo using adipocyte-specific Senp2 knockout (Senp2-aKO) mice. We revealed the molecular mechanism involved in the leptin-induced transcriptional regulation of carnitine palmitoyl transferase 1b (Cpt1b) and long-chain acyl-coenzyme A synthetase 1 (Acsl1) using transfection/reporter assays and chromatin immunoprecipitation. RESULTS SENP2 mediated the increased expression of FAO-associated enzymes, CPT1b and ACSL1, which peaked 24 hours after leptin treatment in adipocytes. In contrast, leptin stimulated FAO through AMPK during the initial several hours after treatment. In white adipose tissues, FAO and mRNA levels of Cpt1b and Acsl1 were increased by 2-fold 24 hours after leptin injection in control mice but not in Senp2-aKO mice. Leptin increased PPARα binding to the Cpt1b and Acsl1 promoters in adipocytes through SENP2. CONCLUSION These results suggest that the SENP2-PPARα pathway plays an important role in leptin-induced FAO in white adipocytes.
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Nan J, Lee JS, Moon JH, Lee SA, Park YJ, Lee DS, Chung SS, Park KS. SENP2 regulates mitochondrial function and insulin secretion in pancreatic β cells. Exp Mol Med 2022; 54:72-80. [PMID: 35064188 PMCID: PMC8814193 DOI: 10.1038/s12276-021-00723-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Revised: 09/22/2021] [Accepted: 10/29/2021] [Indexed: 01/01/2023] Open
Abstract
AbstractIncreasing evidence has shown that small ubiquitin-like modifier (SUMO) modification plays an important role in metabolic regulation. We previously demonstrated that SUMO-specific protease 2 (SENP2) is involved in lipid metabolism in skeletal muscle and adipogenesis. In this study, we investigated the function of SENP2 in pancreatic β cells by generating a β cell-specific knockout (Senp2-βKO) mouse model. Glucose tolerance and insulin secretion were significantly impaired in the Senp2-βKO mice. In addition, glucose-stimulated insulin secretion (GSIS) was decreased in the islets of the Senp2-βKO mice without a significant change in insulin synthesis. Furthermore, islets of the Senp2-βKO mice exhibited enlarged mitochondria and lower oxygen consumption rates, accompanied by lower levels of S616 phosphorylated DRP1 (an active form of DRP1), a mitochondrial fission protein. Using a cell culture system of NIT-1, an islet β cell line, we found that increased SUMO2/3 conjugation to DRP1 due to SENP2 deficiency suppresses the phosphorylation of DRP1, which possibly induces mitochondrial dysfunction. In addition, SENP2 overexpression restored GSIS impairment induced by DRP1 knockdown and increased DRP1 phosphorylation. Furthermore, palmitate treatment decreased phosphorylated DRP1 and GSIS in β cells, which was rescued by SENP2 overexpression. These results suggest that SENP2 regulates mitochondrial function and insulin secretion at least in part by modulating the phosphorylation of DRP1 in pancreatic β cells.
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Nan J, Lee JS, Lee SA, Lee DS, Park KS, Chung SS. An Essential Role of the N-Terminal Region of ACSL1 in Linking Free Fatty Acids to Mitochondrial β-Oxidation in C2C12 Myotubes. Mol Cells 2021; 44:637-646. [PMID: 34511469 PMCID: PMC8490201 DOI: 10.14348/molcells.2021.0077] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Revised: 07/15/2021] [Accepted: 08/03/2021] [Indexed: 12/25/2022] Open
Abstract
Free fatty acids are converted to acyl-CoA by long-chain acyl-CoA synthetases (ACSLs) before entering into metabolic pathways for lipid biosynthesis or degradation. ACSL family members have highly conserved amino acid sequences except for their N-terminal regions. Several reports have shown that ACSL1, among the ACSLs, is located in mitochondria and mainly leads fatty acids to the β-oxidation pathway in various cell types. In this study, we investigated how ACSL1 was localized in mitochondria and whether ACSL1 overexpression affected fatty acid oxidation (FAO) rates in C2C12 myotubes. We generated an ACSL1 mutant in which the N-terminal 100 amino acids were deleted and compared its localization and function with those of the ACSL1 wild type. We found that ACSL1 adjoined the outer membrane of mitochondria through interaction of its N-terminal region with carnitine palmitoyltransferase-1b (CPT1b) in C2C12 myotubes. In addition, overexpressed ACSL1, but not the ACSL1 mutant, increased FAO, and ameliorated palmitate-induced insulin resistance in C2C12 myotubes. These results suggested that targeting of ACSL1 to mitochondria is essential in increasing FAO in myotubes, which can reduce insulin resistance in obesity and related metabolic disorders.
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Kim HI, Lee JS, Kwak BK, Hwang WM, Kim MJ, Kim YB, Chung SS, Park KS. Metformin Ameliorates Lipotoxic β-Cell Dysfunction through a Concentration-Dependent Dual Mechanism of Action. Diabetes Metab J 2019; 43:854-866. [PMID: 31339010 PMCID: PMC6943256 DOI: 10.4093/dmj.2018.0179] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Accepted: 01/15/2019] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND Chronic exposure to elevated levels of free fatty acids contributes to pancreatic β-cell dysfunction. Although it is well known that metformin induces cellular energy depletion and a concomitant activation of AMP-activated protein kinase (AMPK) through inhibition of the respiratory chain, previous studies have shown inconsistent results with regard to the action of metformin on pancreatic β-cells. We therefore examined the effects of metformin on pancreatic β-cells under lipotoxic stress. METHODS NIT-1 cells and mouse islets were exposed to palmitate and treated with 0.05 and 0.5 mM metformin. Cell viability, glucose-stimulated insulin secretion, cellular adenosine triphosphate, reactive oxygen species (ROS) levels and Rho kinase (ROCK) activities were measured. The phosphorylation of AMPK was evaluated by Western blot analysis and mRNA levels of endoplasmic reticulum (ER) stress markers and NADPH oxidase (NOX) were measured by real-time quantitative polymerase chain reaction analysis. RESULTS We found that metformin has protective effects on palmitate-induced β-cell dysfunction. Metformin at a concentration of 0.05 mM inhibits NOX and suppresses the palmitate-induced elevation of ER stress markers and ROS levels in a AMPK-independent manner, whereas 0.5 mM metformin inhibits ROCK activity and activates AMPK. CONCLUSION This study suggests that the action of metformin on β-cell lipotoxicity was implemented by different molecular pathways depending on its concentration. Metformin at a usual therapeutic dose is supposed to alleviate lipotoxic β-cell dysfunction through inhibition of oxidative stress and ER stress.
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Koo YD, Lee JS, Lee SA, Quaresma PGF, Bhat R, Haynes WG, Park YJ, Kim YB, Chung SS, Park KS. SUMO-specific protease 2 mediates leptin-induced fatty acid oxidation in skeletal muscle. Metabolism 2019; 95:27-35. [PMID: 30902749 PMCID: PMC7398119 DOI: 10.1016/j.metabol.2019.03.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Revised: 02/28/2019] [Accepted: 03/15/2019] [Indexed: 12/13/2022]
Abstract
BACKGROUND AND PURPOSE In addition to the central nervous system-mediated action, leptin also directly induces fatty acid oxidation in skeletal muscle. Rapid induction of FAO by leptin is mediated by the AMP-activated protein kinase (AMPK) pathway, but the mechanism of prolonged FAO by leptin was previously unknown. In an earlier study, we showed that free fatty acids increase transcription of small ubiquitin-like modifier (SUMO) specific protease 2 (SENP2) in skeletal muscle, and that SENP2 stimulates expression of FAO-associated enzymes by deSUMOylating peroxisome proliferator-activated receptors, PPARδ and PPARγ. In this study, we examine whether SENP2 is involved in prolonged stimulation of FAO by leptin. METHODS The Effect of leptin on expression of SENP2 and on SENP2-mediated FAO was investigated by using western blotting and real time qPCR of C2C12 myotubes, and of C2C12 myotubes in which expression of specific genes was knocked down using siRNAs. Additionally, muscle-specific SENP2 knockout mice were generated to test the involvement of SENP2 in leptin-induced FAO in vivo. RESULTS We show that leptin treatment of C2C12 myotubes causes signal transducer and activator of transcription 3 (STAT3) to bind to the Senp2 promoter, inducing SENP2 expression. We also show that leptin increases the binding of PPARδ and PPARγ to PPRE sites in the promoters of two FAO-associated genes: long-chain acyl-CoA synthetase 1 (Acsl1) or carnitine palmitoyl transferase 1b (Cpt1b). When SENP2 is knocked down in myotubes, leptin-induced expression of FAO-associated enzymes and prolonged increase of FAO are suppressed, but rapid increase of FAO is unaffected. In addition, leptin-induced expression of FAO-associated enzymes was not observed in muscle tissue of SENP2 knockout mice. CONCLUSIONS We demonstrate that the peripheral actions of leptin on FAO are mediated by two different pathways: AMPK causes a rapid increase in FAO, and SENP2 of the STAT3 pathway causes a slow, prolonged increase in FAO.
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Oh JE, Choi OK, Park HS, Jung HS, Ryu SJ, Lee YD, Lee SA, Chung SS, Choi EY, Lee DS, Gho YS, Lee H, Park KS. Direct differentiation of bone marrow mononucleated cells into insulin producing cells using pancreatic β-cell-derived components. Sci Rep 2019; 9:5343. [PMID: 30926860 PMCID: PMC6441031 DOI: 10.1038/s41598-019-41823-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Accepted: 03/04/2019] [Indexed: 12/31/2022] Open
Abstract
Transplantation of stem cell-derived insulin producing cells (IPCs) has been proposed as an alternative to islet transplantation for the treatment of diabetes mellitus. However, current IPC differentiation protocols are focused on generating functional cells from the pluripotent stem cells and tend to rely on multistep, long-term exposure to various exogenous factors. In this study, we addressed the observation that under stress, pancreatic β-cells release essential components that direct the differentiation of the bone marrow nucleated cells (BMNCs) into IPCs. Without any supplementation with known differentiation-inducing factors, IPCs can be generated from BMNCs by in vitro priming for 6 days with conditioned media (CM) from the β-cells. In vitro primed BMNCs expressed the β-cell-specific transcription factors, as well as insulin, and improved hyperglycemia and glucose intolerance after transplantation into the streptozotocin-induced diabetic mice. Furthermore, we have found that components of the CM which trigger the differentiation were enclosed by or integrated into micro particles (MPs), rather than being secreted as soluble factors. Identification of these differentiation-directing factors might enable us to develop novel technologies required for the production of clinically applicable IPCs.
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Abstract
Peroxisome proliferator-activated receptor γ (PPARγ) is a member of the nuclear receptor family and plays an important role in adipocyte differentiation, glucose homeostasis, and insulin sensitivity. Thiazolidinediones (TZDs), synthetic ligands of PPARγ, have been used for the treatment of diabetes mellitus for two decades. TZDs were expected to be amazing drugs not only for type 2 diabetes but also for metabolic syndrome and atherosclerotic vascular disease because they can reduce both insulin resistance and inflammation in experimental studies. However, serious unwanted effects pushed TZDs back to an optional second-tier drug for type 2 diabetes. Nevertheless, PPARγ is still one of the most important targets for the treatment of insulin resistance and diabetes mellitus, and novel strategies to modulate PPARγ activity to enhance its beneficial effects and reduce unwanted adverse effects are anticipated. Recent studies showed that post-translational modification (PTM) of PPARγ regulates PPARγ activity or stability and may be a novel way to optimize PPARγ activity with reduced adverse effects. In this review, we will focus on recent advances in PTM of PPARγ and the mechanisms regulating PPARγ function as well as in the development of PPARγ modulators or agonists.
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Chung SS, Zheng JS, Burket SR, Brooks BW. Select antibiotics in leachate from closed and active landfills exceed thresholds for antibiotic resistance development. ENVIRONMENT INTERNATIONAL 2018; 115:89-96. [PMID: 29550713 DOI: 10.1016/j.envint.2018.03.014] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Revised: 03/07/2018] [Accepted: 03/11/2018] [Indexed: 05/23/2023]
Abstract
Though antibiotic resistance (ABR) represents a major global health threat, contributions of landfill leachate to the life cycle of antibiotics and ABR development are poorly understood in rapidly urbanizing regions of developing countries. We selected one of the largest active landfills in Asia and two landfills that have been closed for 20 years to examine antibiotic occurrences in leachates and associated hazards during wet and dry season sampling events. We focused on some of the most commonly used human antibiotics in Hong Kong, one of the most populous Asian cities and the fourth most densely populated cities in the world. Seven antibiotics (cephalexin [CLX], chloramphenicol [CAP], ciprofloxacin [CIP], erythromycin [ERY], roxithromycin [ROX], trimethoprim [TMP], sulfamethoxazole [SMX]) were quantitated using HPLC-MS/MS generally following previously reported methods. Whereas CLX, CAP, ROX and SMX in leachates did not exceed ABR predicted no effect concentrations (PNECs), exceedances were observed for CIP, ERY and TMP in some study locations and on some dates. In fact, an ABR PNEC for CIP was exceeded in leachates during both sampling periods from all study locations, including leachates that are directly discharged to coastal systems. These findings highlight the importance of developing an advanced understanding of pharmaceutical access, usage and disposal practices, effectiveness of intervention strategies (e.g., leachate treatment technologies, drug take-back schemes), and contributions of landfill leachates to the life cycle of antibiotics and ABR development, particularly in rapidly urbanizing coastal regions with less advanced waste management systems than Hong Kong.
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Hwang CJ, Chung SS, Lee KY, Lee JH, Moon SH, Kim JH, Cho KJ, Ahn JS, Kim DS, Park YS, Park HJ. Analgesic Efficacy and Safety of Prolonged-Release Oxycodone/Naloxone in Korean Patients with Chronic Pain from Spinal Disorders. Clin Orthop Surg 2018; 10:33-40. [PMID: 29564045 PMCID: PMC5851852 DOI: 10.4055/cios.2018.10.1.33] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Accepted: 11/07/2017] [Indexed: 11/16/2022] Open
Abstract
Background A prolonged-release formulation of oxycodone/naloxone has been shown to be effective in European populations for the management of chronic moderate to severe pain. However, no clinical data exist for its use in Korean patients. The objective of this study was to assess efficacy and safety of prolonged-release oxycodone/naloxone in Korean patients for management of chronic moderate-to-severe pain. Methods In this multicenter, single-arm, open-label, phase IV study, Korean adults with moderate-to-severe spinal disorder-related pain that was not satisfactorily controlled with weak opioids and nonsteroidal anti-inflammatory drugs received prolonged-release oral oxycodone/naloxone at a starting dose of 10/5 mg/day (maximum 80/40 mg/day) for 8 weeks. Changes in pain intensity and quality of life (QoL) were measured using a numeric rating scale (NRS, 0–10) and the Korean-language EuroQol-five dimensions questionnaire, respectively. Results Among 209 patients assessed for efficacy, the mean NRS pain score was reduced by 25.9% between baseline and week 8 of treatment (p < 0.0001). There was also a significant improvement in QoL from baseline to week 8 (p < 0.0001). The incidence of adverse drug reactions was 27.7%, the most common being nausea, constipation, and dizziness; 77.9% of these adverse drug reactions had resolved or were resolving at the end of the study. Conclusions Prolonged-release oxycodone/naloxone provided significant and clinically relevant reductions in pain intensity and improved QoL in Korean patients with chronic spinal disorders. (ClinicalTrials.gov identifier: NCT01811238)
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Choi JW, Ohn JH, Jung HS, Park YJ, Jang HC, Chung SS, Park KS. Carnitine induces autophagy and restores high-fat diet-induced mitochondrial dysfunction. Metabolism 2018; 78:43-51. [PMID: 28966077 DOI: 10.1016/j.metabol.2017.09.005] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Revised: 09/12/2017] [Accepted: 09/23/2017] [Indexed: 12/19/2022]
Abstract
OBJECTIVE Autophagy is suppressed in skeletal muscle and the liver with insulin resistance induced by a high-fat diet. Autophagy is essential for maintaining mitochondrial function, and dysfunctional mitochondria are associated with insulin resistance. As carnitine treatment is well known to improve insulin resistance by promoting mitochondrial function, we investigated if carnitine affects autophagy in the skeletal muscle of a high-fat diet-induced rodent model of obesity. RESULTS After 6weeks on a high-fat diet (48kcal% fat), mice developed glucose intolerance, and the gastrocnemius muscle showed a decrease in insulin signaling and mitochondrial function, which was reversed after carnitine (100mg/kg/day) treatment by oral gavage for 2weeks. Swollen mitochondria with destroyed cristae were observed in the skeletal muscle of high-fat diet-fed mice but were not there after carnitine treatment. High-fat diet decreased LC3B-II, a marker of autophagosome formation, and increased sequestosome 1 (SQSTM1), expression of which was reversed after carnitine treatment. In C2C12 myotubes, prolonged treatment with palmitate suppressed autophagy, which was relieved by carnitine treatment. However, the induction of autophagy by carnitine in C2C12 myotubes was not observed after knock-down of peroxisome proliferator-activated receptor γ (PPARγ), which is known to regulate autophagy. CONCLUSION We conclude that the removal of dysfunctional mitochondria by induction of autophagy through PPARγ may be a novel mechanism by which carnitine improves insulin resistance and mitochondrial dysfunction in obesity.
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Choi S, Ryoo SB, Park KJ, Kim DS, Song KH, Kim KH, Chung SS, Shin EJ, Cho YB, Oh ST, Kang WK, Kim MH. Autologous adipose tissue-derived stem cells for the treatment of complex perianal fistulas not associated with Crohn's disease: a phase II clinical trial for safety and efficacy. Tech Coloproctol 2017; 21:345-353. [PMID: 28567691 DOI: 10.1007/s10151-017-1630-z] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Accepted: 04/16/2017] [Indexed: 12/18/2022]
Abstract
PURPOSE Injection of adipose tissue-derived stem cells (ASCs) is a novel method for the treatment of complex perianal fistulas. We aimed to evaluate the safety and efficacy of ASCs in the treatment of complex anal fistulas not associated with Crohn's disease. METHODS A phase II clinical trial was performed comparing two different doses of ASCs (group 1: 1 × 107 cells/mL and group 2: 2 × 107 cells/mL). Eligible patients were administered an amount of ASCs proportional to the length of the fistula by injection into the submucosal layer surrounding the internal opening and inside of the fistula tract. ASCs at twice the initial concentration were administered if complete closure was not achieved within 8 weeks. The efficacy endpoint was the complete closure of fistulas 8 weeks after injection. Patients demonstrating complete closure at week 8 were subjected to follow-up for 6 months. RESULTS Fifteen patients were injected with ASCs; thirteen completed the study. Complete closure was observed in 69.2% (9/13) of patients at 8 weeks. Three of five patients in group 1, and six of eight in group 2 displayed complete closure; no significant differences were observed between the groups. Six of nine patients who showed complete closure participated in additional follow-up; five (83.3%) showed persistent response at 6 months. No grade 3 or 4 adverse events (AEs) were observed; observed AEs were not related to ASC treatment. CONCLUSION ASCs might be a good option for the treatment of complex perianal fistulas are not healed by conventional operative procedures.
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Shah SA, Yoon GH, Chung SS, Abid MN, Kim TH, Lee HY, Kim MO. Novel osmotin inhibits SREBP2 via the AdipoR1/AMPK/SIRT1 pathway to improve Alzheimer's disease neuropathological deficits. Mol Psychiatry 2017; 22:407-416. [PMID: 27001618 PMCID: PMC5322276 DOI: 10.1038/mp.2016.23] [Citation(s) in RCA: 141] [Impact Index Per Article: 20.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Revised: 02/02/2016] [Accepted: 02/04/2016] [Indexed: 12/22/2022]
Abstract
Extensive evidence has indicated that a high rate of cholesterol biogenesis and abnormal neuronal energy metabolism play key roles in Alzheimer's disease (AD) pathogenesis. Here, for we believe the first time, we used osmotin, a plant protein homolog of mammalian adiponectin, to determine its therapeutic efficacy in different AD models. Our results reveal that osmotin treatment modulated adiponectin receptor 1 (AdipoR1), significantly induced AMP-activated protein kinase (AMPK)/Sirtuin 1 (SIRT1) activation and reduced SREBP2 (sterol regulatory element-binding protein 2) expression in both in vitro and in vivo AD models and in Adipo-/- mice. Via the AdipoR1/AMPK/SIRT1/SREBP2 signaling pathway, osmotin significantly diminished amyloidogenic Aβ production, abundance and aggregation, accompanied by improved pre- and post-synaptic dysfunction, cognitive impairment, memory deficits and, most importantly, reversed the suppression of long-term potentiation in AD mice. Interestingly, AdipoR1, AMPK and SIRT1 silencing not only abolished osmotin capability but also further enhanced AD pathology by increasing SREBP2, amyloid precursor protein (APP) and β-secretase (BACE1) expression and the levels of toxic Aβ production. However, the opposite was true for SREBP2 when silenced using small interfering RNA in APPswe/ind-transfected SH-SY5Y cells. Similarly, osmotin treatment also enhanced the non-amyloidogenic pathway by activating the α-secretase gene that is, ADAM10, in an AMPK/SIRT1-dependent manner. These results suggest that osmotin or osmotin-based therapeutic agents might be potential candidates for AD treatment.
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Shah SA, Yoon GH, Chung SS, Abid MN, Kim TH, Lee HY, Kim MO. Osmotin reduced amyloid beta (Aβ) burden by inhibiting SREBP2 expression in APP/PS1 mice. Mol Psychiatry 2017; 22:323. [PMID: 28220046 DOI: 10.1038/mp.2017.12] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Moon MK, Kang GH, Kim HH, Han SK, Koo YD, Cho SW, Kim YA, Oh BC, Park DJ, Chung SS, Park KS, Park YJ. Thyroid-stimulating hormone improves insulin sensitivity in skeletal muscle cells via cAMP/PKA/CREB pathway-dependent upregulation of insulin receptor substrate-1 expression. Mol Cell Endocrinol 2016; 436:50-8. [PMID: 27452800 DOI: 10.1016/j.mce.2016.07.018] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Revised: 07/13/2016] [Accepted: 07/16/2016] [Indexed: 11/21/2022]
Abstract
Thyroid-stimulating hormone (TSH) receptor is expressed in extrathyroidal tissues such as hepatocytes, adipocytes, and skeletal muscle, which suggests a possible novel role of TSH in various metabolic processes in extrathyroidal tissues independent of thyroid hormones. We investigated whether TSH has any effects on glucose tolerance and insulin sensitivity in the skeletal muscle using diet-induced obesity (DIO) mouse models and rodent skeletal muscle cells. TSH improved glucose tolerance in DIO mice and this was associated with an improvement of skeletal muscle insulin sensitivity resulting from the increased expression of insulin receptor substrate (IRS)-1 protein and mRNA therein. TSH significantly increased both basal and insulin-stimulated glucose transport in rat L6 myotubes and increased the expression of IRS-1 protein and mRNA in these cells as well. TSH also stimulated Irs1 promoter activation; this stimulation was abolished by protein kinase A (PKA) inhibition using H89 or by mutation of the cAMP-response element site located at -1155 to -875 bp of the Irs1 promoter region, supporting a novel role of TSH activated-cAMP/PKA/CREB signaling in the regulation of Irs1 expression. In conclusion, TSH improves insulin sensitivity in skeletal muscle by increasing Irs1 gene expression. This regulatory effect is mediated by a PKA-CREB-dependent pathway.
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Kim MJ, Koo YD, Kim M, Lim S, Park YJ, Chung SS, Jang HC, Park KS. Rg3 Improves Mitochondrial Function and the Expression of Key Genes Involved in Mitochondrial Biogenesis in C2C12 Myotubes. Diabetes Metab J 2016; 40:406-413. [PMID: 27535645 PMCID: PMC5069397 DOI: 10.4093/dmj.2016.40.5.406] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/03/2015] [Accepted: 01/04/2016] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND Panax ginseng has glucose-lowering effects, some of which are associated with the improvement in insulin resistance in skeletal muscle. Because mitochondria play a pivotal role in the insulin resistance of skeletal muscle, we investigated the effects of the ginsenoside Rg3, one of the active components of P. ginseng, on mitochondrial function and biogenesis in C2C12 myotubes. METHODS C2C12 myotubes were treated with Rg3 for 24 hours. Insulin signaling pathway proteins were examined by Western blot. Cellular adenosine triphosphate (ATP) levels and the oxygen consumption rate were measured. The protein or mRNA levels of mitochondrial complexes were evaluated by Western blot and quantitative reverse transcription polymerase chain reaction analysis. RESULTS Rg3 treatment to C2C12 cells activated the insulin signaling pathway proteins, insulin receptor substrate-1 and Akt. Rg3 increased ATP production and the oxygen consumption rate, suggesting improved mitochondrial function. Rg3 increased the expression of peroxisome proliferator-activated receptor γ coactivator 1α, nuclear respiratory factor 1, and mitochondrial transcription factor, which are transcription factors related to mitochondrial biogenesis. Subsequent increased expression of mitochondrial complex IV and V was also observed. CONCLUSION Our results suggest that Rg3 improves mitochondrial function and the expression of key genes involved in mitochondrial biogenesis, leading to an improvement in insulin resistance in skeletal muscle. Rg3 may have the potential to be developed as an anti-hyperglycemic agent.
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Lee KW, Kwak SH, Koo YD, Cho YK, Lee HM, Jung HS, Cho YM, Park YJ, Chung SS, Park KS. F-box only protein 9 is an E3 ubiquitin ligase of PPARγ. Exp Mol Med 2016; 48:e234. [PMID: 27197753 PMCID: PMC4910150 DOI: 10.1038/emm.2016.31] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Revised: 01/01/2016] [Accepted: 01/07/2016] [Indexed: 01/07/2023] Open
Abstract
Peroxisome proliferator-activated receptor gamma (PPARγ) is a critical regulator of carbohydrate and lipid metabolism, adipocyte differentiation and inflammatory response. Post-translational modification of PPARγ and its degradation involve several pathways, including the ubiquitin–proteasome system. Here, we identified F-box only protein 9 (FBXO9) as an E3 ubiquitin ligase of PPARγ. We screened interacting partners of PPARγ using immunoprecipitation and mass spectrometric analysis and identified FBXO9 as an E3 ubiquitin ligase of PPARγ. FBXO9 directly interacted with PPARγ through the activation function-1 domain and ligand-binding domain. FBXO9 decreased the protein stability of PPARγ through induction of ubiquitination. We found that the F-box motif of FBXO9 was required for its ubiquitination function. The activity of PPARγ was significantly decreased by FBXO9 overexpression. Furthermore, FBXO9 overexpression in 3T3-L1 adipocytes resulted in decreased levels of endogenous PPARγ and suppression of adipogenesis. These results suggest that FBXO9 is an important enzyme that regulates the stability and activity of PPARγ through ubiquitination.
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Choi JW, Kim M, Song H, Lee CS, Oh WK, Mook-Jung I, Chung SS, Park KS. DMC (2',4'-dihydroxy-6'-methoxy-3',5'-dimethylchalcone) improves glucose tolerance as a potent AMPK activator. Metabolism 2016; 65:533-42. [PMID: 26975545 DOI: 10.1016/j.metabol.2015.12.010] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/17/2015] [Revised: 12/16/2015] [Accepted: 12/17/2015] [Indexed: 12/13/2022]
Abstract
OBJECTIVE We investigated the effect and regulatory mechanism of 2',4'-dihydroxy-6'-methoxy-3',5'-dimethylchalcone (DMC) isolated from Cleistocalyx operculatus on metabolic parameters in myotubes, adipocytes and an obese mouse model. MATERIALS AND METHODS Myotubes and adipocytes were incubated with or without DMC. Glucose uptake, fatty acid oxidation, AMPK activation and adipocytes differentiation were investigated. To examine in vivo effect of DMC, 30mg/kg/day DMC was administered by oral gavage for 2weeks in high fat fed C57BL/6 male mice and intra-peritoneal glucose tolerance test was performed. In order to examine whether DMC directly activates AMPK, we performed cell free AMPK assay and surface plasmon resonance spectroscopy analysis. RESULT DMC increases glucose uptake and fatty acid oxidation (FAO) in myotubes. Also, DMC inhibits adipocyte differentiation in 3T3-L1 cells. Interestingly, DMC stimulates phosphorylation of AMP-dependent protein kinase (AMPK) alpha subunit (T172) by directly binding to AMPK, which results in the activation of AMPK. Furthermore, DMC binds AMPK with a higher affinity than AMP. When AMPK was knocked down, the stimulatory effect of DMC on FAO and its inhibitory effect on adipogenesis were abolished. These results suggest that the effects of DMC were primarily mediated by AMPK activation. In addition, treating mice fed a high fat diet with DMC improved glucose tolerance and significantly increased FAO of the muscles. CONCLUSION DMC, as a novel AMPK activator, shows anti-diabetic effects in cell culture systems, such as myotubes and adipocytes, and in a diet-induced obese mouse model.
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Choi JW, Jo A, Kim M, Park HS, Chung SS, Kang S, Park KS. BNIP3 is essential for mitochondrial bioenergetics during adipocyte remodelling in mice. Diabetologia 2016; 59:571-81. [PMID: 26693709 DOI: 10.1007/s00125-015-3836-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2015] [Accepted: 11/13/2015] [Indexed: 01/09/2023]
Abstract
AIMS/HYPOTHESIS Adipose tissue is a highly versatile system in which mitochondria in adipocytes undergo significant changes during active tissue remodelling. BCL2/adenovirus E1B 19 kDa protein-interacting protein 3 (BNIP3) is a mitochondrial protein and a known mitochondrial quality regulator. In this study, we investigated the role of BNIP3 in adipocytes, specifically under conditions of peroxisome proliferator-activated receptor-γ (PPARγ)-induced adipose tissue remodelling. METHODS The expression of BNIP3 was evaluated in 3T3-L1 adipocytes in vitro, C57BL/6 mice fed a high-fat diet and db/db mice in vivo. Mitochondrial bioenergetics was investigated in BNIP3-knockdown adipocytes after rosiglitazone treatment. A putative peroxisome proliferator hormone responsive element (PPRE) was characterised by promoter assay and electrophoretic mobility shift assay (EMSA). RESULTS The protein BNIP3 was more abundant in brown adipose tissue than white adipose tissue. Furthermore, BNIP3 expression was upregulated by 3T3-L1 pre-adipocyte differentiation, starvation and rosiglitazone treatment. Conversely, BNIP3 expression in adipocytes decreased under various conditions associated with insulin resistance. This downregulation of BNIP3 was restored by rosiglitazone treatment. Knockdown of BNIP3 in adipocytes inhibited rosiglitazone-induced mitochondrial biogenesis and function, partially mediated by the 5' AMP-activated protein kinase (AMPK)-peroxisome proliferator-activated receptor γ, co-activator 1 α (PGC1α) signalling pathway. Rosiglitazone treatment increased the transcription level of Bnip3 in the reporter assay and the presence of the PPRE site in the Bnip3 promoter was demonstrated by EMSA. CONCLUSIONS/INTERPRETATION The protein BNIP3 contributes to the improvement of mitochondrial bioenergetics that occurs on exposure to rosiglitazone. It may be a novel therapeutic target for restoring mitochondrial dysfunction under insulin-resistant conditions.
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Ahn HY, Kim HH, Kim YA, Kim M, Ohn JH, Chung SS, Lee YK, Park DJ, Park KS, Moore DD, Park YJ. Thyroid Hormone Regulates the mRNA Expression of Small Heterodimer Partner through Liver Receptor Homolog-1. Endocrinol Metab (Seoul) 2015; 30:584-92. [PMID: 26485468 PMCID: PMC4722415 DOI: 10.3803/enm.2015.30.4.584] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2015] [Revised: 08/24/2015] [Accepted: 09/24/2015] [Indexed: 01/14/2023] Open
Abstract
BACKGROUND Expression of hepatic cholesterol 7α-hydroxylase (CYP7A1) is negatively regulated by orphan nuclear receptor small heterodimer partner (SHP). In this study, we aimed to find whether thyroid hormone regulates SHP expression by modulating the transcriptional activities of liver receptor homolog-1 (LRH-1). METHODS We injected thyroid hormone (triiodothyronine, T3) to C57BL/6J wild type. RNA was isolated from mouse liver and used for microarray analysis and quantitative real-time polymerase chain reaction (PCR). Human hepatoma cell and primary hepatocytes from mouse liver were used to confirm the effect of T3 in vitro. Promoter assay and electrophoretic mobility-shift assay (EMSA) were also performed using human hepatoma cell line. RESULTS Initial microarray results indicated that SHP expression is markedly decreased in livers of T3 treated mice. We confirmed that T3 repressed SHP expression in the liver of mice as well as in mouse primary hepatocytes and human hepatoma cells by real-time PCR analysis. LRH-1 increased the promoter activity of SHP; however, this increased activity was markedly decreased after thyroid hormone receptor β/retinoid X receptor α/T3 administration. EMSA revealed that T3 inhibits specific LRH-1 DNA binding. CONCLUSION We found that thyroid hormone regulates the expression of SHP mRNA through interference with the transcription factor, LRH-1.
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Koo YD, Choi JW, Kim M, Chae S, Ahn BY, Kim M, Oh BC, Hwang D, Seol JH, Kim YB, Park YJ, Chung SS, Park KS. SUMO-Specific Protease 2 (SENP2) Is an Important Regulator of Fatty Acid Metabolism in Skeletal Muscle. Diabetes 2015; 64:2420-31. [PMID: 25784542 PMCID: PMC4477359 DOI: 10.2337/db15-0115] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/26/2015] [Accepted: 02/27/2015] [Indexed: 12/27/2022]
Abstract
Small ubiquitin-like modifier (SUMO)-specific proteases (SENPs) that reverse protein modification by SUMO are involved in the control of numerous cellular processes, including transcription, cell division, and cancer development. However, the physiological function of SENPs in energy metabolism remains unclear. Here, we investigated the role of SENP2 in fatty acid metabolism in C2C12 myotubes and in vivo. In C2C12 myotubes, treatment with saturated fatty acids, like palmitate, led to nuclear factor-κB-mediated increase in the expression of SENP2. This increase promoted the recruitment of peroxisome proliferator-activated receptor (PPAR)δ and PPARγ, through desumoylation of PPARs, to the promoters of the genes involved in fatty acid oxidation (FAO), such as carnitine-palmitoyl transferase-1 (CPT1b) and long-chain acyl-CoA synthetase 1 (ACSL1). In addition, SENP2 overexpression substantially increased FAO in C2C12 myotubes. Consistent with the cell culture system, muscle-specific SENP2 overexpression led to a marked increase in the mRNA levels of CPT1b and ACSL1 and thereby in FAO in the skeletal muscle, which ultimately alleviated high-fat diet-induced obesity and insulin resistance. Collectively, these data identify SENP2 as an important regulator of fatty acid metabolism in skeletal muscle and further implicate that muscle SENP2 could be a novel therapeutic target for the treatment of obesity-linked metabolic disorders.
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