122 research outputs found
한국인 조기 류마티스 관절염 환자에서 다양한 치료 방법에 따른 효과 분석
의과대학/석사배경: 류마티스 관절염의 치료의 종류 및 방법은 점차 늘어나고 있지만, 관절 손상과 기능 저하를 막는 최적의 치료법에 대한 제시는 여전히 뚜렷하지 않다. 이에 우리는 한국인 조기 류마티스 관절염 환자에 적합한 치료법을 밝히고자 4가지의 서로 다른 치료 방법의 임상 및 방사선학적 결과를 연구하고자 한다. 대상 및 방법: 195명의 환자를 4개의 서로 다른 치료군: 순차적 초기 단일요법 (그룹1), 단계적 초기 병합요법 (그룹2), 고용량 스테로이드의 단계적 감량과 초기 병합요법 (그룹3), 종양괴사인자 길항제와 methotrexate 병합요법 (그룹4)에 배정하였다. 임상적 관해(28개의 관절 질병활성도 점수<2.6)를 목표로 매달 평가 후 치료를 조절하였다. 결과: 일차적 결과인 건강 평가 설문은 치료 전을 제외하고 각 그룹별 시기별 차이를 보이지 않았다. 변형된 Sharp/Van der Heijde 방사선 관절 점수가 악화되는 환자는 그룹 4에서보다 그룹 1에서 좀더 자주 관찰되었으나, 통계학적인 의미는 없었다 (그룹 1에서 25% vs 그룹 4에서 6%). 이차적 결과였던 American College of Rheumatology (ACR) 치료 반응은 치료 후 3개월 째 ACR 20, 50이, 6개월 째 ACR 20, 50, 70이 그룹 1,2와 그룹 3,4간에 의미있는 차이를 보였으나, 이는 6개월이 경과하며 차이가 소실되었다. 치료 후 1년이 지났을 때 각 그룹간에는 통계학적 차이가 없었으나, 모든 군에서 약 60%의 관해율을 보였다 (각 그룹 1-4에서 54%, 61%, 62%, 62%).결론: 한국인 조기 류마티스 관절염 환자에서, 뚜렷한 목표와 집중 관찰을 하며 치료를 적용해 나가면, 치료법과 상관 없이 높은 비율의 임상적 관해를 이룰 수 있다.ope
Takayasu arteritis associated with ulcerative colitis and optic neuritis: First case in Korea
Takayasu arteritis (TA) is a chronic vasculitis that affects the aortic arch and its primary branches. Ulcerative colitis (UC) is an inflammatory bowel disease of unknown etiology. Patients diagnosed with both TA and UC have rarely been reported. The pathogenesis of TA and UC is uncertain, but cell-mediated mechanisms play an important role in both diseases, and a genetic factor is thought to have an effect on the coincidence of these two diseases. We herein report a 38-year-old female with TA who had a history of UC with optic neuritis. We believe that this is the first case of the coexistence of TA and UC in Korea.ope
Differences in Clinical Manifestations and Outcomes between Adult and Child Patients with Henoch-Schonlein Purpura
We aimed to investigate differences in clinical manifestations and outcomes between adult and child patients with Henoch-Schönlein purpura (HSP), and to analyze the factors associated with poor prognosis for HSP nephritis. This retrospective 10-yr study enrolled 160 patients with HSP who visited Severance Hospital. Purpura was mostly detected in lower extremities, but purpura in upper extremities was more frequently observed in adults than children (41.7% vs 19.3%). Children had a greater frequency of arthralgia (55.4% vs 27.1%), while adults had a greater frequency of diarrhea (20% vs 1.6%). Anemia, elevated C-reactive protein, and level of IgA were more frequently observed in adults (25% vs 7.1%, 65.6% vs 38.4%, 26.3% vs 3.5%). Renal involvement in adults was more severe than in children (79.2% vs 30.4%). Chronic renal failure showed a significant difference in outcomes of HSP between adults (10.4%) and children (1.8%) after a follow up period of an average of 27 months. Furthermore, renal insufficiency at diagnosis was significantly related to the progression to chronic renal failure. Our results showed several differences in the clinical features of HSP between adults and children. Adults with HSP had a higher frequency of renal insufficiency and worse renal outcomes than children. Renal insufficiency at diagnosis might be of predictive value for the progression to chronic renal failure in HSP patients.ope
Ventricular Tachyarrhythmias in a Patient with Andersen-Tawil Syndrome
Andersen-Tawil syndrome (ATS), a rare autosomal dominant disorder, is characterized by periodic paralysis, dysmorphic features and cardiac arrhythmias. This syndrome is caused by mutations of KCNJ2 gene, which encodes inward rectifying potassium channel. Here, we report an 18-year-old girl who was presented with life-threatening cardiac arrhythmia and acute respiratory distress. She was diagnosed with ATS, based on dysmorphic features, ventricular arrhythmia, and periodic paralysis. This is the first case to be reported in Korea who experienced a fatal cardiac arrest and respiratory failure caused by ATS.ope
Application of the 2013 ACR/EULAR classification criteria for systemic sclerosis to patients with Raynaud's phenomenon
INTRODUCTION: We investigated how many patients, who presented with Raynaud's phenomenon (RP) and who had not been classified as systemic sclerosis (SSc), would be reclassified as SSc, if the 2013 American College of Rheumatology (ACR)/the European League Against Rheumatism (EULAR) classification criteria were used. We also analyzed the predictive values of the reclassification as SSc in those patients.
METHODS: We consecutively enrolled 64 patients with RP and 60 patients with SSc. We applied the new classification criteria to them, reclassified them, and compared variables between those who were newly classified as SSc and those who were not or previously classified as SSc.
RESULTS: Seventeen of 64 patients (26.5%), who presented with RP, but did not fulfill the 1980 ACR classification criteria, were newly classified as SSc by the 2013 ACR/EULAR classification criteria. The newly classified patients as SSc showed increased frequencies of sclerodactyly, digital tip ulcer, telangiectasia, abnormal nailfold capillaries and the presence of anti-centromere antibody, compared to those not and telangiectasia and anti-centromere antibody, compared to the previously classified patients. For the reclassification as SSc, the variables with independent predictive value were sclerodactyly (odds ratio (OR) 60.025), telangiectasia (OR 13.353) and the presence of anti-centromere antibody (OR 11.168).
CONCLUSIONS: Overall, 26.5% of the patients, who presented with RP, but who did not fulfill the 1980 ACR classification criteria, were newly classified as SSc according to the 2013 ACR/EULAR classification criteria. Sclerodactyly, telangiectasia, and the presence of anti-centromere antibody had independent predictive value for reclassifying patients with RP as SSc.ope
Successful Prasugrel Rescue Therapy in Clopidogrel Resistant Patients Who Had Recurrent Stent Thrombosis of Drug-Eluting-Stent: The Role of Prasugrel in Clopidogrel Nonresponders
Stent thrombosis is a very serious problem after drug-eluting stent (DES) implantation even though its incidence is about or less than 1%. As the clopidogrel resistance is expected to play an important role in the occurrence of stent thrombosis, new anti-platelet agents overcoming this issue can give us another choice. We experienced a case of a 58-year-old male with successful prasugrel rescue therapy in a patient with clopidogrel resistance who had recurrent stent thrombosis following DES implantation.ope
Typical 18-FDG-PET/CT Findings of Polymyalgia Rheumatica: A Case Report
Polymyalgia rheumatica (PMR) is an inflammatory rheumatic condition characterized by generalized pain and morning stiffness in the shoulders, hip girdle, and neck. Since the pathogenesis of PMR is still uncertain, the diagnosis of PMR depends on clinical features. There have been several studies regarding radiological tools for the diagnosis of PMR. Recent studies using 18-FDG-PET showed bursitis, synovitis, uptake in the spinous process and asymptomatic large-vessel vasculitis in PMR patients. However, there was no report on the efficacy of 18-FDG-PET for diagnosis of PMR in Korea. Here, we are first reporting a case of a Korean patient with PMR, who had radiological findings including bursitis, synovitis, uptake in the spinous process and asymptomatic large-vessel vasculitis on 18-FDG-PET/CT.ope
유기물 혹은 반데르발스 접합을 통한 이황화몰리브덴 포토드랜지스터의 광전기적 특성 연구
학위논문(박사)--서울대학교 대학원 :자연과학대학 물리·천문학부(물리학전공),2019. 8. 이탁희.본 학위 논문에서는 이황화 몰리브덴 포토트랜지스터의 광 전자적 특성에 대해 연구를 수행하였다. 박사 학위 과정에서 2차원 물질 기반의 포토 트랜지스터의 광 전자적 특성을 주로 탐구하였다. 2차원 물질은 원자스케일의 얇은 두께로 인해 많은 빛의 양을 흡수할 수 없고 상당히 큰 엑시톤 결합 에너지를 가지고 있다. 이 두 요인은 2차원 물질 기반의 광 검출기의 광 반응성을 억제시킨다. 그러나 포토 트랜지스터는 드래인 전압 및 게이트 전압을 이용해서 광 특성을 증폭시킬 수 있는 구조이기 때문에, 2차원 물질 기반의 포토 트랜지스터의 광 전자적 특성을 향상시킬 수 있다.
본 학위 논문의 2장에서는 이황화 몰리브덴 포토트랜지스터의 광 특성 향상시키는 연구를 소개한다. 이황화 몰리브덴 표면에 유기물질을 이용한 표면처리로 광 반응성과 광 스위칭 특성을 개선시킬 수 있었다. 광 전자적 특성 성능향상을 위한 연구뿐만 아니라, 이차원 물질의 본질적인 광 전자적 특성에 대해서 연구를 수행하였다. 본 학위 논문의 3장에서는 반데르발스 헤테로 구조를 이용하여 제작한 완전히 투명한 이황화 몰리브덴 포토트랜지스터의 본연의 광 전자적 특성을 설명하였다. 4장에서는 이황화 몰리브덴 뿐만 아니라, 홀 도핑이 텅스텐 디셀레나이드 기반의 포토트랜지스터의 광전자 특성에 미치는 영향에 대해서도 요약하였다.
광 전자적 성능을 증폭하기 위해서 외부 전기장을 이용하는 포토트랜지스터의 구조적 특성 때문에, 강한 전기장 내에서의 전기적 그리고 광 전자적 특성에 대해서 연구를 수행하였다. 이황화 몰리브덴 트랜지스터가 강한 전기장 내에서 어떤 전기적 특성이 나타나는지에 대해 연구를 수행했고 흥미로운 현상들을 발견했다. 5장과 6장에서는 강한 전기장 내에서 발생하는 애벌런치 항복 현상과 이차원 물질과 기판사이에서의 전자 트랩현상에 대해서 설명하였다.In this thesis, the optoelectronic characteristics of MoS2 phototransistors are mainly studied. The major reason of exploring the optoelectronic characteristics of 2D materials-based phototransistors, not of photodiodes, during my doctorate course is because 2D materials cannot absorb significant amount of light and they have considerably high exciton binding energy, originating from their atomically thin thickness. These features suppress the optoelectronic performance in the perspective of 2D materials-based photodetectors. However, the phototransistor can amplify the photodetection capability by employing the external electric fields, such as drain-source voltage and gate-source voltage.
After introduction of my thesis work in Chapter 1, in Chapter 2 I will summarize a research result of improving photosensitivity of MoS2 phototransistors conducted in 2014 as my first research topic. I demonstrated that a surface treatment with organic materials on MoS2 could improve the photoresponsivity and photoswitching characteristics. In addition to the exploration for improving optoelectronic performance, I became interested in the intrinsic optoelectronic characteristics of 2D materials during my doctorate course. In Chapter 3, I summarize the intrinsic optoelectronic characteristics of fully transparent MoS2 phototransistors employing a van der Waals heterostructure. And, in Chapter 4, the effects of p-doping on optoelectronic characteristics of WSe2 phototransistors are explained.
Because of the nature of phototransistors using external electric fields for amplifying the optoelectronic performance, I studied the electrical and optoelectronic phenomena of 2D-based phototransistors under the high electric fields. I have discovered the interesting electrical phenomena in MoS2 transistors under the high electric fields in the process of arranging for the experimental setup for studying optoelectronic characteristics. However, I could not finish this research on the optoelectronic characteristics under the high electric fields due to the insufficient time. I summarized the thickness-dependent avalanche breakdown phenomena and charge trapping dynamics under the high electric fields in Chapters 5 and 6.List of Contents
Abstract ....................................................................................................... i
List of Contents .......................................................................................... ii
Chapter 1. Introduction ............................................................................ 8
1.1. Brief introduction of TMDs and MoS2 ............................................... 8
1.2. Optoelectronic characteristics of MoS2 and a MoS2-based heterostructure for enhancing photosensitivity .................................. 9
1.3. Intrinsic optoelectronics of MoS2 phototransistors .......................... 10
1.4. Electrical characteriscitcs of MoS2 under high electric fields .......... 11
1.5. Outline of this thesis ......................................................................... 12
References ............................................................................................... 13
Chapter 2. Optoelectronic characteristics of MoS2 phototransistors via vertical heterostructure with organic material ................. 16
2.1. Introduction ...................................................................................... 17
2.2. Experiments ...................................................................................... 19
2.2.1. Device fabrication process ..................................................... 19
2.3. Results and discussions .................................................................... 20
2.3.1. Electrical chararcteristics of MoS2 FETs ............................. 20
2.3.2. Modulation of threshold voltage via a heterostructure .......... 22
2.3.3. Enhancement of photoresponsive characteristics .................. 26
2.3.4. Improved photoswitching characteristics .............................. 34
2.4. Conclusion ........................................................................................ 38
Figure captions ........................................................................................ 39
References ............................................................................................... 41
Chapter 3. Intrinsic optoelectronic characteristics of MoS2 phototransistors via a fully transparent van der Waalsheterostructure ...................................................................... 45
3.1. Introduction ...................................................................................... 46
3.2. Experiments ...................................................................................... 48
3.2.1. Device fabrication process ..................................................... 48
3.2.2. Electrical and optical characterizations ................................. 49
3.3. Results and discussions .................................................................... 49
3.3.1. Structure and electrical characteristics of transparent MoS2 phototransistors .................................................................... 49
3.3.2. Spectroscopic characteristics of the transparent MoS2 phototransistors ...................................................................... 52
3.3.3. Comparision of the optoelectronic characteristics of MoS2 phototransistors on transparent and opaque substrates .......... 53
3.3.4. Intrinsic optoelectronic characteristics of transparent MoS2 phototransistors under visible light ........................................ 58
3.3.5. Time-resolved photoresponse characteristics in transparent MoS2 phototransisotrs .......................................................... 63
3.4. Conclusion ........................................................................................ 65
Figure captions ........................................................................................ 66
References ............................................................................................... 67
Chapter 4. Effect of facile p-doping on electrical and optoelectronic characteristics of ambipolar WSe2 field-effect transistors 73
4.1. Introduction ...................................................................................... 74
4.2. Experiments ...................................................................................... 75
4.3. Results and discussions .................................................................... 76
4.3.1. Change of electrical and photoswitching characteristics ....... 76
4.3.2. XPS analysis .......................................................................... 83
4.3.3. Photoluminescence analysis .................................................. 84
4.4. Conclusion ........................................................................................ 87
Figure captions ........................................................................................ 88
References ............................................................................................... 89
Chapter 5. Thickness-dependent avalanche breakdown phenomena inMoS2 field effect transistors under high electric fields ...... 93
5.1. Introduction ...................................................................................... 94
5.2. Experiments ...................................................................................... 95
5.2.1. Device fabrication process ..................................................... 95
5.2.2. Electrical and optical characterizations ................................. 96
5.3. Results and discussions .................................................................... 97
5.3.1. Structure and electrical characteristics of MoS2 FETs ........... 97
5.3.2. Effects of lateral electric field, thermal stress caused by Joule heating, and carrier concentration on electrical breakdown in MoS2 FETs ........................................................................... 100
5.3.3. Unique thickness dependency of MoS2 on avalanche multiplication ....................................................................... 104
5.3.4. Temperature dependence of avalanche multiplication in MoS2 FETs ..................................................................................... 108
5.3.5. Comparision of critical electric field with conventional semiconductor materials ...................................................... 110
5.4. Conclusion ...................................................................................... 111
Figure captions ...................................................................................... 112
References ............................................................................................. 114
Chapter 6. Trapped charge modulation at the MoS2/SiO2 interface by lateral electric field in MoS2 field-effect transistors ........ 119
6.1. Introduction .................................................................................... 120
6.2. Experiments .................................................................................... 121
6.2.1. Device fabrication process ................................................... 121
6.2.2. Electrical characterizations .................................................. 122
6.3. Results and discussions .................................................................. 122
6.3.1. Structure and electrical characteristics of MoS2 FETs ......... 122
6.3.2. Charge trapping and detrapping phenomena depending on the VDS measurement range ........................................................ 124
6.3.3. Charge detrapping processes by the multiple VDS sweeps ... 128
6.3.4. The inflence of h-BN buffer layer inserted between MoS2 channel and SiO2 interfaces ................................................. 130
6.4. Conclusion ...................................................................................... 132
Figure captions ...................................................................................... 133
References ............................................................................................. 134
Chapter 7. Summary ............................................................................. 138
감사의 글 .............................................................................................. 141Docto
Analysis of causes of idiopathic genu vara and its treatment
의학과/석사[한글]
기능상 혹은 미용상 장애를 초래하는 하지의 특발성 내반 변형의 원인을 분석하고 이에 대한 수술적 치료법을 제시하고자 10년간 양쪽 하지의 특발성 내반 변형을 주소로 내원하여 수술적 치료 후 최소 1년 이상 추시(평균 3.1년)가 가능하였던 28명의 환자를 대상으로 기립 방사선 촬영과 컴퓨터 단층 촬영을 통해 하지의 선열 및 염전과 관계되는 방사선학적 계측을 시행하고 변형의 종류, 병원을 방문하게 되는 연령과 주요 증상, 수술의 주요 목적, 변형에 따른 수술적 방법 및 치료 결과를 평가하였다. 원인에 따라 각각 대퇴 전염각 증가군, 근위 경골의 내반 변형이 동반된 경골의 외회전각 증가군 및 근위 경골의 내반 변형군의 3개 군으로 분류하고, 각각의 원인에 대한 회전 및 교정 절골술을 시행한 결과 만족할 만한 기능적, 미용적 교정이 되는 것을 확인하였다.이에 본 연구자는, 더 이상의 자연교정을 기대하기 어려운 8-10세 이후의 환자에서 나타난 특발성 내반 변형을 수술적으로 치료하고자 할 경우에는, 실제 변형이 존재하는 해부학적 위치를 분석하여 단순히 근위 경골의 내반 변형에 의한 것인지 혹은 하지의 염전에 의하거나 동반된 것인지를 감별하고, 그 원인에 따라 수술적 치료를 시행할 필요가 있다는 결론을 얻었으며, 이와 같이 원인 분석에 따른 치료를 시행하면 보다 효과적인 치료결과를 얻을 것으로 사료된다.
[영문]28 patients who were treated with corrective surgery for idiopathic genu vara during last 10 years were studied to find out the anatomical causes of deformity, and evaluate their results of surgical treatment.Radiograhic measurements were made using the standing orthoroentgenogram and computerized axial tomography scan. Anatomical causes of idiopathic genu vara, and age on admission, chief complaints, or objectives of surgery were evaluated. Functional and cosmetic results after surgery were also evaluated.Idiopathic genu vara were categorized into three groups: a group associated with increased femoral anteversion, a group associated with tibia vara and increased external rotation of the tibia, and a group associated with tibia vara. Satisfactory functional and cosmetic results after corrective surgeries were based on accurate analysis of their anatomical causes.To make a surgical treatment plan for idiopathic genu vara, an accurate analysis based on rotational as well as angular deformities should be appreciated.ope
TM4SF5-의존적 간 상피세포와 대식세포의 상호관계에 의한 간 섬유화 연구
학위논문(석사)--서울대학교 대학원 :약학대학 약학과,2020. 2. 이정원.만성적 간질환은 지방간, 간염 및 섬유화/경화 그리고 간암을 포함하며 만성적인 염증 환경이 중요한 역할을 하는 것으로 알려져 있다. 특히, 간 섬유화는 만성 간 손상에 의한 결과물로 비가역적인 간 세포의 손상과 염증반응으로 인한 세포외기질(Extracellular matrix, ECM)의 축적에 의해 일어난다. 간 섬유화의 악화는 간경화와 간암으로 이어지며, 현재까지 간 섬유화의 정확한 진단 방법과 치료 약물에 대해서는 잘 알려진 바가 없다. 이전 연구에 따르면 간 섬유화가 진행된 마우스 간 조직과 인간 간 세포에서 Tetraspanin superfamily에 속하는 막 단백질인 Transmembrane 4L 6 superfamily 5(TM4SF5)의 유전자와 단백질의 발현이 증가되어 있는 것으로 알려진 바 있다. 따라서 이를 토대로 본 연구에서는 TM4SF5가 간 섬유화를 유발하는 과정에서 간 상피세포와 대식세포 사이의 상호작용 및 면역적 환경에 미치는 영향에 대해 알아보고자 하였다.
SNU-449 세포와 마우스 간 조직의 RNA-Sequencing을 통해, TM4SF5의 발현이 증가하면 IL-6의 하위 유전자의 발현 또한 함께 증가하는 것을 알 수 있었다. 그리고 Open database를 통해서 TM4SF5와 CCL20과 CXCL10 양의 상관관계를 알 수 있었다. 이를 바탕으로 CCL20과 CXCL10이 TM4SF5 발현에 의해 조절됨을 알 수 있었다.
다음으로, CCL20과 CXCL10의 발현을 조절하는 IL-6를 간 상피세포에 처리하였다. 이때, TM4SF5가 발현되지 않는 세포에 비해 TM4SF5가 발현되는 세포에서 STAT3의 인산화가 증가되었을 뿐만 아니라 CCL20, CXCL10의 발현이 증가된다는 것을 확인하였다. IL-6의 수용체와 TM4SF5의 물리적인 결합을 위한 면역침강법을 통해 IL-6의 작용과 TM4SF5의 발현이 상관성 있음을 확인하였다. 이러한 조건에서 TM4SF5의 선택적 억제제인 TSAHC[4′-(p-toluenesulfonylamido)-4-hydroxychalcone]를 처리하였을 경우 간 세포 내 IL-6 수용체와 TM4SF5의 물리적 결합이 소실 되고, CCL20, CXCL10의 발현 역시 TSAHC의 농도에 의존적으로 감소함을 확인하였다.
한편, 대식세포는 주변 환경에 따라 M1(classical) 또는 M2(alternative)로 분극화된다. M1-대식세포와 M2-대식세포의 Conditioned Media(C.M.)을 얻은 뒤 간 상피세포에 처리해 CCL20, CXCL10의 발현을 측정하거나 IL-6 수용체의 항체를 함께 처리한 실험을 통해 M1-대식세포에서 IL-6가 분비됨을 알 수 있었다. 즉, IL-6는 M1-대식세포에서 분비되며, 간 상피세포의 TM4SF5가 IL-6의 신호전달에 관여해 간 상피세포에서 CCL20, CXCL10을 분비하는 것으로 파악되었다. 이때 TM4SF5가 발현되는 간 상피세포로부터 분비된 CCL20, CXCL10은 M2-대식세포로 분화가 유도되는 것을 더욱 촉진하는 것을 THP-1과 Bone-marrow derived macrophage의 M2 marker(Arg-1, Ppar-γ, CD206 등)가 증가한 것을 통해 알 수 있었다. M2-대식세포는 Hepatic stellate cell을 활성화 시켜 Col1α1을 생성하며, 간 상피세포를 자극해 Laminin γ2의 형성을 유도하였다.
세포 수준의 실험 결과를 동물 수준에서 확인하기 위해, CCl4 처리에 의해 간 섬유화가 유도된 마우스 모델을 구축하여 분석하였다. CCl4의 처리는 TM4SF5의 증가와 Plasma ALT, 간 무게/몸무게 비율의 증가를 일으켰으며, 이는 간 손상의 지표이다. 그러나 CCl4와 TSHAC를 함께 처리하면 Plasma ALT, 간 무게/몸무게 비율이 덜 증가 하거나 궁극적으로 간 손상이 덜 일어난 것을 확인하였다. 그리고 조직 염색과 mRNA level을 통해 α-SMA, Collagen1α1의 발현이 TSAHC를 함께 처리한 그룹에서 감소한 것을 확인하였다. 또한, 간의 Ccl20, Cxcl10의 발현이 감소되고 이로 인해 간으로 유입되는 대식세포가 감소한 것을 알 수 있었다.
한편, 간 상피세포의 TM4SF5와 M1-대식세포에 의존적으로 증가하는 Ccl20의 간 섬유화에서의 역할을 알기 위해 Ccl20 siRNA를 정맥주사하고 CCl4로 간 섬유화를 유도하였다. 그 결과, Ccl20 siRNA을 함께 처리한 그룹이 CCl4만 처리한 그룹에 비해 염증의 정도와 ECM의 생성, 대식세포의 유입이 감소한 것을 조직 염색과 mRNA level을 통해 확인하였다. 결과적으로, TM4SF5를 발현하는 상피세포로부터 Ccl20의 분비가 TM4SF5-의존적 섬유화에 중요함을 확인할 수 있었다.
따라서, 이 연구를 통해 간 섬유화 과정에서 TM4SF5 의존적인 CCL20, CXCL10의 발현, 그에 따른 대식세포 분극화의 중요성을 알 수 있었으며, 간 섬유화 과정에서 TM4SF5를 발현하는 간 상피세포와 대식 세포의 상호작용을 조절하여 간 섬유화를 치료할 수 있는 가능성을 제시하였다.Chronic liver disease includes fatty liver, hepatitis, fibrosis/cirrhosis in which the inflammatory environment is known to play an important role. In particular, hepatic fibrosis is a consequence of chronic liver damage and is caused by the accumulation of extracellular matrix (ECM) following chronic damage of hepatocytes and thereafter inflammatory reactions. Exacerbation of liver fibrosis leads to cirrhosis and eventually cancer. Therefore, earlier diagnosis and cure of liver fibrosis would be clinically beneficial. The previous researches have shown that expression level of transmembrane 4 L6 superfamily 5 (TM4SF5) in hepatocytes, a membrane protein belonging to the tetraspanin superfamily, increased in fibrotic human and mouse liver tissues. However, the roles of the microenvironment of the TM4SF5-positive hepatocytes in the development of fibrosis has not been examined. Therefore, the aim of this study was to investigate the effect of TM4SF5 on the cross-talk between hepatocytes and macrophages as well as the immune environment which would be involved in the progression of liver fibrosis.
RNA-Sequencing of SNU449 cells and mice liver tissues without or with TM4SF5 expression showed that the expression of certain cytokine/chemokine genes down-stream of IL-6 increased by the expression of TM4SF5. The open database also showed a positive correlation between TM4SF5 and CCL20/CXCL10, indicating that CCL20 and CXCL10 could be regulated by TM4SF5 expression. Thus, this study has been examined the roles of CCL20 and CXCL10 in the TM4SF5-dependent fibrosis in the liver.
First, when IL-6, a representative pro-inflammatory cytokine, was treated to hepatocytes, the phosphorylation of STAT3 was increased in cells expressing TM4SF5 as compared to cells not expressing TM4SF5. Expression of CCL20 and CXCL10, as known as down-stream genes of IL-6, were upregulated by TM4SF5 expression. The physical binding of IL-6 receptor α with TM4SF5 was confirmed by co-immunoprecipitation, indicating that TM4SF5-positive hepatocytes could be affected by IL-6 signaling, presumably for CCL20 and CXCL10 expression. Under these conditions, treatment of TSAHC [4-(p-toluenesulfonylamido)-4-hydroxychalcone], a specific inhibitor of TM4SF5, disrupted the physical binding of IL-6 receptor α and TM4SF5 in hepatocytes. In addition, expression of CCL20 and CXCL10 were also gradually reduced by TSAHC treatment in a dose-dependent manner.
Macrophages, on the other hand, are polarized into M1 or M2 depending on their surrounding microenvironment. When the conditioned-media (CM) from M1-macrophages or M2-macrophages differentiated from THP-1 monocytes was treated to hepatocytes without or with IL-6 receptor antibody, the expression of CCL20 and CXCL10 in hepatocytes increased via the presumable secretion of IL-6 in M1-macrophages. In other words, IL-6 was secreted from M1-macrophages, and TM4SF5 in hepatocytes were involved in the signaling to synthesize CCL20 and CXCL10 by macrophage IL-6. Furthermore, CCL20 and CXCL10 secreted from TM4SF5-positive hepatocytes promoted the polarization of M2-macrophage, which was confirmed by increases in M2 markers (Arg-1, Ppar-γ, and CD206) in THP-1 and bone-marrow derived macrophage. The CM from M2-macrophages then activated hepatic stellate cells to produce Col1α1 (collagen 1 chain α1) mRNA and stimulated hepatocytes to induce the expression of Lamc2 (laminin γ2), suggesting their roles in fibrosis development.
To confirm these results using in vivo animal model, a hepatic fibrosis mouse model was induced by Intraperitoneal injection of CCl4. Injection of CCl4 resulted in an increase in TM4SF5, plasma ALT and liver weight to body weight ratio, which were signs of liver damage. However, the injection of CCl4 together with TSHAC resulted in reduction of plasma ALT and liver weight to body weight ratio. Immunohistochemistry (IHC) and qPCR analyses confirmed that the expression of α-SMA, collagen1 α1 were higher in the group injected with CCl4, which were declined by additional TSAHC treatment. In addition, it was found that the expression of CCL20 and CXCL10 in the CCl4-induced fibrotic livers were reduced by TSAHC treatment, and importantly the macrophages infiltration into the liver was also the case, too.
Because the expression of CCL20 in hepatocytes depended on TM4SF5 expression and M1-macrophages, I wanted to know the significance of CCL20 in liver fibrosis. Ccl20 siRNA was intravenously injected during IP injections with CCl4. As a result, IHC and qPCR showed that the group treated with CCl4 and Ccl20 siRNA reduced degree of inflammation, accumulation of ECM, and infiltration of macrophages, although the group treated with CCl4 alone showed higher levels of them. Thus, secretion of CCL20 in hepatocytes depending on TM4SF5 expression can be important for TM4SF5-dependent fibrosis.
Altogether, this study showed that the importance of TM4SF5-dependent expression of CCL20 and CXCL10 and the effect of M2 macrophage polarization in the process of liver fibrosis. It is reasonable that liver fibrosis can be alleviated by regulating the cross-talks of hepatocytes expressing TM4SF5 with macrophages.ABSTRACT 1
INTRODUCTION 6
MATERIALS AND METHODS 9
RESULTS 15
DISCUSSION 39
REFERENCES 43
국문초록 47Maste
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