Modulation of the Transcriptional Activity of Peroxisome Proliferator-Activated Receptor Gamma by Protein-Protein Interactions and Post-Translational Modifications

Peroxisome proliferator-activated receptor gamma (PPARγ) belongs to a nuclear receptor superfamily; members of which play key roles in the control of body metabolism principally by acting on adipose tissue. Ligands of PPARγ, such as thiazolidinediones, are widely used in the treatment of metabolic syndromes and type 2 diabetes mellitus (T2DM). Although these drugs have potential benefits in the treatment of T2DM, they also cause unwanted side effects. Thus, understanding the molecular mechanisms governing the transcriptional activity of PPARγ is of prime importance in the development of new selective drugs or drugs with fewer side effects. Recent advancements in molecular biology have made it possible to obtain a deeper understanding of the role of PPARγ in body homeostasis. The transcriptional activity of PPARγ is subject to regulation either by interacting proteins or by modification of the protein itself. New interacting partners of PPARγ with new functions are being unveiled. In addition, post-translational modification by various cellular signals contributes to fine-tuning of the transcriptional activities of PPARγ. In this review, we will summarize recent advancements in our understanding of the post-translational modifications of, and proteins interacting with, PPARγ, both of which affect its transcriptional activities in relation to adipogenesis.ope

개의 급성 척수 손상 모델에서 정맥 투여된 지방유래 중간엽 줄기 세포와 Methylprednisolone의 항산화 효과

This study was performed to investigate the antioxidant effect of intravenously injected adipose-derived mesenchymal stem cells (AD-MSCs) in an acute canine spinal cord injury (SCI) model. The antioxidant capacities of AD-MSCs, conditioned cell culture medium and methylprednisolone sodium succinate (MPSS) were measured by total antioxidant capacity kit. Sixteen adult dogs were assigned to four groups according to the treatments after SCI by epidural balloon compression: control group (no treatment), MPSS group (MPSS treatment), MSCs group (AD-MSCs treatment), and MSCs+MPSS group (AD-MSCs treatment with MPSS). AD-MSCs of 1x107 cells were intravenously injected once a day for 3 days from 6 h after SCI. MPSS was also intravenously injected according to the protocol for acute SCI. Three-nitrotyrosine (3-NT), 4-hydroxynenonal (4-HNE) and protein carbonyl (PC) as markers for oxidative damage events were measured by ELISA kits. Deep pain perception and gastrointestinal hemorrhage were also evaluated with toe pinching and fecal occult blood (FOB) test kit. The AD-MSCs (1x107 cells) and their conditioned medium (1 ml) showed antioxidant capacities as potent as 100 uM of alpha-tocopherol. 3-NT levels of MPSS and MSCs+MPSS groups were significantly lower than that of the control (p < 0.05). 4-HNE levels of all treatment groups were significantly lower than that of the control. PC levels of MSCs and MSCs+MPSS groups were significantly lower than that of control group. Groups treated with the MSCs and/or MPSS, were improved deep pain restoration clinically, but the groups with MPSS treatment had a side effect of gastrointestinal hemorrhage indicated by FOB test. These results suggested that the intravenous injection of AD-MSCs with MPSS treatment in dogs with SCI had an antioxidant effect which might improve pain perception and prevent the gastrointestinal disorders.본 연구는 개의 급성 척수 손상 모델에서 정맥 투여된 지방유래 중간엽 줄기 세포의 항산화 효과를 알아보기 위하여 수행되었다. 실험에 사용된 지방유래 줄기 세포, 줄기 세포 배양 배지, methyl-prednisolone sodium succinate (MPSS)의 항산화능은 total antioxidant capacity (TAC) 키트를 사용하여 평가하였다. 열여섯 마리의 비글 견에서 척수강 내 balloon catheter를 장착하여 척수 손상을 유발하였으며, 처치 방법에 따라 대조군(척수 손상 유발 후 무처치, n=4), MPSS 군(척수 손상 유발 후 MPSS 처치, n=4), mesenchymal stem cells (MSCs) 군(척수 손상 유발 후 지방유래 줄기 세포 처치, n=4), 그리고 MSCs+MPSS 군(척수 손상 유발 후 줄기 세포와 MPSS 처치, n=4)의 4 군으로 나누어 실험하였다. 줄기 세포의 처치는 1 x 107 개의 세포를 척수 손상 유발 6시간 후부터 3 일 간 총 3 회 정맥 투여 하였다. MPSS는 급성 척수 손상 처치 기준에 따라 30 mg/kg 1 회 투여 후 5.4 mg/kg/h 로 48 시간 동안 점적 투여 하였다. 손상 척수에서 산화적 반응물을 확인하기 위해 3-nitrotyrosine (3-NT), 4-hydroxy-nonenal (4-HNE), 그리고 protein carbonyl (PC)를 측정하였다. 임상적 평가를 위해 심부 통각 반응과 분변 내 잠혈 반응 검사를 실시하였다. 줄기 세포(1 x 107개) 와 줄기 세포 배양 배지(1 ml)의 항산화 능력은 비타민 E (알파 토코페롤)의 100 uM 수준으로 확인되었다. 대조군과 비교하여, MPSS와 MSCs+MPSS 처치 군에서 3-NT의 농도가 유의적으로 감소하였다 (p < 0.05). 4-HNE 농도는 모든 실험군에서 유의적으로 감소하였다. PC 농도는 MSCs와 MSCs+MPSS 처치 군에서 유의적으로 감소하였다. 줄기 세포와 MPSS 처치 군에서 심부 통각 반응의 회복이 빠르게 개선됨을 확인하였으나, MPSS 처치 군에서 위장관 내 출혈의 부작용을 분변 내 잠혈 반응 검사를 통해 확인하였다. 이상의 결과로 보아 중간엽 줄기 세포와 MPSS의 정맥주사는 급성 척수 손상 개에서 항산화 효과를 보이며 긍정적인 치료효과를 기대할 수 있다.INTRODUCTION ∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙ 1 MATERIALS AND METHODS 1. Isolation, culture, and differentiation test of AD-MSCs ∙∙∙∙∙∙∙∙ 4 2. Animals ∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙ 5 3. Induction of SCI ∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙ 5 4. Injection of AD-MSCs and MPSS ∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙ 7 5. Sampling of injured spinal cord tissue ∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙ 7 6. Clinical assessments ∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙ 7 7. Oxidant metabolites assessments ∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙ 8 8. In vitro TAC assay ∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙ 8 9. Statistical analyses ∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙ 8 RESULTS 1. Clinical assessments ∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙ 9 2. Oxidant metabolites levels ∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙ 11 3. TAC assay ∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙ 13 DISCUSSION ∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙ 14 REFERENCES ∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙ 18 국문초록 ∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙ 25Maste

아임계 및 초임계 조건에서 극저온 스월 유동의 불안정성

학위논문 (박사)-- 서울대학교 대학원 : 기계항공공학부, 2015. 2. 윤영빈.Instability characteristics of cryogenic swirl flows were experimentally investigated. The cryogenic liquid nitrogen was injected into a high-pressure chamber through a simplex swirl injector under subcritical to supercritical conditions of nitrogen. High-speed photography with backlight imaging was used to obtain images of the temporally changing flow. The set of images was analyzed by the image processing method. The instability frequency was measured by flow image processing and the laser beam diagnostics. Surface instability of the flow under subcritical to supercritical condition was investigated. Comparing the flow images of the cryogenic and conventional swirl flows, different behaviors were noted, and it was hypothesized that the instability of the cryogenic swirl flow was dominated by the precessing vortex core in the central toroidal recirculation zone. When the ambient condition of the flow was changed from subcritical to supercritical, the phase change and subsequent density change of the injectant differed and flow actions, such as the behavior of the downstream flow, the spray angle, the wavelength, and the propagation velocity, changed drastically. When measuring the frequency of the flow instability, it was found to correspond to that of the precessing vortex core instability. The frequency decreased with the ambient pressure due to the decreasing flow velocity, but it did not change drastically when the surrounding conditions changed from subcritical to supercritical. This implies that the interface of the flow is highly affected by the density of the phase-changed injectant, but that the instability of the flow is determined by the flow in a liquid state. The dynamic characteristics of a cryogenic swirl flow under supercritical conditions were experimentally investigated using a mode decomposition method. Superposed instability structures and vortex ring structures were found in the instantaneous flow image. The spray angle was decreased under supercritical conditions because of the unusual phase change of the injectant inside the injector. Two kinds of modes were deduced by POD analysis of the flow images. The analysis showed that two types of modes exist: a symmetric/tilted-ring shaped mode and an anti-symmetric shaped mode. The Kelvin-Helmholtz instability mechanism generated the symmetric mode. The anti-symmetric structure was created by helical instability, which was generated by the instability of the liquid film inside the injector under subcritical conditions. However, under supercritical conditions, the precessing vortex core in the central toroidal recirculation zone determined the unstable behavior of the flow. A spatial and temporal analysis of the POD modes supported this explanation for the instability. Meanwhile, the spatial characteristics of the coherent structures became similar in the downstream region or under supercritical conditions, which implicates the strong influence of the state of the injectant in flow behavior.CHAPTER 1. INTRODUCTION 1 1.1 Background and Motivation 1 1.2 Survey of Relevant Literature 5 1.2.1 Characteristics of fluid under supercritical condition 5 1.2.2 Single and coaxial jet flow 6 1.2.3 Jet flow with external excitation 8 1.2.4 Simplex swirl flow 9 1.3 Scope of Study 10 CHAPTER 2. EXPERIMENTAL METHOD 11 2.1 Experimental Apparatus 11 2.1.1 Design procedure of swirl injector 11 2.1.2 High-pressure chamber 17 2.1.3 Cryogenic fluid feeding system 19 2.2 Flow Measurement 20 2.2.1 High-speed photography 21 2.2.2 Flow instability frequency measurement 23 CHAPTER 3. SURFACE INSTABILITY ON CRYOGENIC SWIRL FLOW UNDER SUB- TO SUPERCRITICAL CONDITIONS 24 3.1 Background and Objectives 24 3.2 Experimental Methods 27 3.2.1 Injector design 27 3.2.2 Experimental conditions 28 3.2.3 Experimental techniques 30 3.3 Results and Discussion 31 3.3.1 Characteristics of the cryogenic swirl flow 31 3.3.2 Effect of the ambient pressure on a cryogenic swirl flow surface 34 3.3.3 Instabilty analysis of a cryogenic swirl flow surface 43 CHAPTER 4. DYNAMIC CHARACTERISTICS OF A CRYOGENIC SWIRL FLOW UNDER SUPERCRITICAL CONDITIONS 46 4.1 Background and Objectives 46 4.2 Experimental Methods 48 4.2.1 Injector design 48 4.2.2 Experimental conditions 50 4.2.3 Experimental techniques 51 4.2.4 Proper Orthogonal Decompsition 51 4.3 Results and Discussion 54 4.3.1 Static characteristics of a cryogenic flow 54 4.3.2 POD analysis of flow image 57 4.3.3 Analysis of POD mode 69 CHAPTER 5. CONCLUSION AND FUTURE WORK 74 5.1 Conclusion 74 5.2 Recommendations for Future Work 76 APPENDIX. PROPER ORTHOGONAL DECOMPOSITION 77 A.1 Background 77 A.2 POD Analysis Procedure 77 BIBLIOGRAPHY 81 ABSTRACT IN KOREAN 87Docto

간 조직의 포도당항상성 유지에서 TXNIP의 역할

Dept. of Medical Science/박사Thioredoxin interacting protein (TXNIP) has multiple functions in several pathways involved in the reactive oxygen species (ROS) generation, apoptosis, inflammation and glucose metabolism. TXNIP is upregulated in the hyperglycemic state and represses glucose uptake into several peripheral tissues, resulting in a homeostatic imbalance of glucose. Although TXNIP has relevance to metabolic syndromes such as obesity and type I and II diabetes mellitus, the role and regulation of TXNIP in liver is unclear. To investigate a metabolic role of TXNIP in the liver, Ad-Txnip is administrated to normal mice and an intraperitoneal glucose tolerance test (IPGTT), insulin tolerance test (ITT), and pyruvate tolerance test (PTT) were performed. Overexpression of TXNIP resulted in an impaired glucose, insulin, and pyruvate tolerance in normal mice. After Ad-Txnip administration, the expression of genes involved in glucose metabolism, including glucose-6-phosphatase (G6pc) and glucokinase (Gck) were analysed using qPCR and western blot. Ad-Txnip transduction upregulated G6pc expression and caused a decrease in Gck levels in the liver of normal mice and primary hepatocytes. To understand increased G6pc expression in the liver as a result of TXNIP overexpression, pull down assays for TXNIP and small heterodimer partner (SHP) were performed and confirmed that TXNIP increased G6pc expression by forming a complex with SHP which is known to be a negative modulator of gluconeogenesis. To study for the regulation of Txnip gene expression, luciferase reporter assays and chromatin immunoprecipitation (ChIP) assays using the Txnip promoter were performed to elucidate the interrelationship between carbohydrate response element binding protein (ChREBP) and transcription factor E3 (TFE3) in the regulation of Txnip expression. Furthermore, Txnip expression in diabetic mouse models was decreased by Ad-Tfe3 administration, suggesting that TFE3 may play a negative role through competition with ChREBP at the E-box of the Txnip promoter. These findings demonstrated that TXNIP impairs glucose and insulin tolerance in mice by upregulating G6pc through interaction with SHP and modulating TXNIP expression.ope