Microsoft Word - 21-인경수

Size: px

Start display at page:

Download "Microsoft Word - 21-인경수"

규필 강전
5 years ago
Views:

1 Journal of Bacteriology and Virology Vol. 46, No. 4 p Research Update (Minireview) The Role of Sodium-taurocholate Co-transporting Polypeptide as a Receptor during HBV Infection So-Young Kim 1, Eungyeong Jang 2 and Kyung-Soo Inn 1 * 1 Department of Pharmaceutical Science, College of Pharmacy, Kyung Hee University, Seoul; 2 Department of Internal Medicine, College of Korean Medicine, Kyung Hee University, Seoul, Korea According to World Health Organization, more than 200 million people suffer with chronic hepatitis caused by Hepatitis B virus (HBV) infection worldwide. Chronic hepatitis B causes various complications including liver cirrhosis and hepatocellular carcinoma and approximately 0.5~4.2 million deaths occur annually due to HBV infection. Current therapies such as antivirals and vaccine are often hampered by drug intolerance, side effects, and long-time medication, therefore, the development of powerful anti-hbv drugs is demanded. Recently, sodium taurocholate co-transporting polypeptide (NTCP) receptor was revealed to play a pivotal role in HBV entry into hepatocytes. Cell lines transfected with NTCP receptor enables to analyze HBV life cycle by inducing HBV infection stably, but in vivo models still have some limitations such as high costs, restrictive differentiation, and unveiled cofactors related to human NTCP. Therefore, it requires well-established in vivo models to develop and evaluate novel therapeutic agents targeting NTCP receptor, and viral entry inhibitors that inhibit the early step of viral infection are potent sufficient to substitute for existing antivirals. Key Words: Hepatitis B virus, Receptor, Sodium-taurocholate co-transporting polypeptide, Entry INTRODUCTION B형간염바이러스 (Hepatitis B virus, HBV) 는간염뿐아니라간경화, 간세포암등의원인이되는대표적인바이러스로전세계인구의 3분의 1에해당하는약 20억명의사람이 HBV에감염된적이있을정도로유병률이높다. 그중대부분은경도감염으로수개월이내회복이되지만, 약 3억 5천만명은만성간염으로진행되어간경화와간암의위험에노출된다. 세계질병부담연구 (Global Burden of Disease, GBD) 에서발표한 2013년보고서에서는, HBV 감염으로인한사망자수가매년 78만 7천명정도로질병으로인한전체사망원인중상당한비중을차지하고있 음에도불구하고국제질병전문가들이 HBV 감염에대한적극적인논의를하고있지않다고경고한다. 특히우리나라의경우, 1983년에 HBV 감염을예방할수있는 B형간염백신이도입되고 1995년부터영유아대상정기예방접종사업이시행되면서 10대이하의유병률은현격히감소하였으나여전히매년 200여만명이 HBV 감염으로인한만성간질환으로고통받고있다. 이렇게전세계적으로많은사람이 HBV 감염으로인한만성간질환의위험에노출되어있는것은 HBV가 ' 조용한 ' 바이러스로감염초기에심각한증상이나타나지않아적기의치료나관리없이방치되면서결국간경화, 간암으로까지진행하게되기때문이다 (1). HBV는간세포에감염되어염증을일으키는헤파드나 Received: December 7, 2016/ Revised: December 15, 2016/ Accepted: December 15, 2016 * Corresponding author: Kyung-Soo Inn. Department of Pharmaceutical Science, College of Pharmacy, Kyung Hee University, 26 Kyungheedae-ro, Dongdaemun-gu, Seoul, 02447, Korea. Phone: , Fax: , innks@khu.ac.kr CC This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License ( 335

2 336 S-Y Kim, et al. Figure 1. Structure of Hepatitis B virus. HBV consists of an outer envelope and inner nucleocapsid. The envelop contains HBsAg which comprises three proteins; the small (S), middle (S+ pres2), large (S+preS2+preS1) surface protein. Among them, only the pres1 domain has an infectious capacity. The capsid encloses genomic DNA, DNA polymerase, HBeAg, and HBcAg. 바이러스과 (Hepadnaviridae) 의 DNA 바이러스로, 1965년미국의 Blumberg 가오스트레일리아원주민의혈청에서처음발견하여오스트레일리아항원으로명명하였다. 크기는 42 nm로표면항원 (HBsAg) 이발견되는바이러스바깥쪽껍질 (envelop) 과핵항원 (HBcAg) 이있는캡시드 (capsid) 의이중단백질껍질로구성되어있으며캡시드는 3.2 kbp 크기의 circular partial duplex DNA genome 과 HBV polymerase 단백질을둘러싸고있다. HBsAg은캡시드없이단독으로과잉생산되어내부 DNA 게놈이없는빈원형이나튜브모양의입자의형태로말초혈액내에서발견되기도하는데이경우전염성이없기때문에서브바이러스입자 (subviral particles) 또는공입자 (empty particles) 라고부른다. 42 nm의구형인 Dane 입자는 3.2 kbp의이중가닥 DNA 게놈과그것을둘러싸는캡시드단백질및바깥쪽껍질을모두갖추고있기때문에전염성이있는완전한형태의비리온이다. HBsAg은크기에따라 L-, M-, S- HBsAg로구분되며각각 1:1:4의비율로구성되어있다. S-HBsAg 은 S domain만을, M-HBsAg 은 pre-s2 와 S domain 을, L-HBsAg 은 pre-s1, pre-s2, S domain을가지며특히 pre-s1 domain 은 HBV 감염에중요한역할을하는단백질로간세포의 receptor 에결합하는바이러스리간드역할을한다 (Fig. 1) (2, 3). 최근의연구에따르면 HBV는간세포막의 heparan sulfate proteoglycans (HSPGs) 에부착한후 HBsAg의 pre-s1 domain 이간세포수용체인 sodium taurocholate cotransport polypeptide (NTCP) 에결합하여 endocytosis 를통해간세포안으로진입한다. 진입후 uncoating 과정을겪고 genomic DNA가핵내로이동한다. Genomic DNA는핵안에서 episome 형태로유지되는 HBV DNA인 cccdna (covalently closed circular DNA) 로전환된다. cccdna는 subgenomic RNA (sgrna) 와 pregenomic RNA (pgrna) 로전사되는주형으로사용되어 HBV 증식에필수적인형태이다. pgrna 는세포질로이동하여 HBV의 genome DNA 복제에 RNA 주형으로활용되며결합되어있는역전사효소에의해 genomic DNA로전환된다. 현재임상적으로사용되고있는만성 B형간염치료제로는 IFN-α, pegylated INF-α (peg INF-α) 와 Nucleos(t)ide 유사체인 lamivudine, adefovir, entecavir, telbivudine, tenofovir 등이있다. 다양한항바이러스작용을나타내는 INF-α 는만성 B형간염치료에성공적으로사용되어, 약제내성없이조기 HBeAg 혈청전환과높은 HBsAg 혈청소실률을보이지만피하주사의불편함과감기증상, 우울증같은부작용이나타난다 (4). Nucleos(t)ide 유사체는 HBV polymerases 의작용을경쟁적으로저해하기때문에핵안에서 relaxed circular DNA (rcdna) 의 cccdna 로의전환을억제하여 HBV 증식을막는다. 이러한 Nucleos(t)ide 유사체는피하주사가아닌경구복용방법으로투약되기때문에환자들의약에대한거부감은적지만오랜기간동안

3 NTCP, the Receptor for HBV 337 약을복용하는과정에서발생하는내성이나약물부작용등을피할수없는상황이다 (5). 이와같이 HBV에대한현치료제의여러가지한계점으로인해높은치료율, 짧은치료기간, 치료제에대한낮은저항성과부작용을갖는치료제의개발이시급한상황이다. 한편 HBV는종특이적으로오직사람과몇몇영장류에만감염이된다고보고되고있어서 (6) HBV 치료제개발을위한효율적인동물모델개발이쉽지않다. 이로인하여바이러스의간세포로의진입과정을설명해줄 HBV 의생활사등에대한제반연구가미흡할수밖에없다. 물론사람의일차간세포주 (primary human hepatocyte, PHH) 가 HBV의복제과정과관련된연구에활용되고있기는하지만이용성과가변성면에서한계를보이고있다. 이러한상황에서최근발견된 NTCP 수용체는 HBV가숙주세포안으로들어가는초기진입단계에대한실마리를제공하고 (7), NTCP 수용체를 HepG2 나 Huh7 등의간암세포에발현시켜지속적으로 HBV를복제할수있는세포주를만들어서세포연구의한계를극복하여 HBV 감염에대한새로운치료제개발을앞당길수있다는점에서시사하는바가크다. 이러한이유때문에본종설에서는현재까지진행된 NTCP 에대한발견과정을규명하고그구조와기능을살펴보고지금까지알려진 NTCP를발현하는실험모델과그모델을통해밝혀진 NTCP에특이적으로결합하여 HBV 숙주세포로의진입을경쟁적으로저해하는저해제에대한전반적인내용을조사하였다. NTCP의발견과규명 HBV가숙주의간세포에감염되기위해서는간세포막에존재하는 heparan surface proteoglycan 에부착하여감염을시작하는것이알려졌다 ( 즉, 기존연구에서 HBV의간세포부착단계에서 HSPGs 가주요 binding factor 로작용하여 HBV 감염에핵심적인역할을한다고밝혀진바있다 ) (8). 하지만 HBV가숙주세포에본격적으로들어가기위해서는좀더높은친화력을가지는간세포특이적인수용체가필요하며그수용체를밝히기위한연구가계속되었다 (9). 1986년에 HepG2 세포에결합하는 HBV L-HBsAg 을구성하는 Pre-S1 도메인중아미노산서열 2-47번에해당하는부위 (PLGFFPDHQLDPAFGANSNNPD- WDFNP) 가간세포에결합하는리간드역할을한다고증명하였다 (10). 그러나그당시만하더라도 HBV의 Pre-S1 도메인이간세포에존재하는어떠한수용체에결합하는 지에대해서는명확하게규명하지못하였으나담즙산이간세포내로흡수되는것이억제되는것을통해 HBV가간세포의안과밖을연결해주면서담즙산을흡수하는수용체와관련이있을것이라고예측하였다 (10). 2005년에이르러 HBsAg을구성하는 pre-s1 도메인의아미노산 (amino acid, AA) 을분석하여 AA 9-18 부분이간세포에존재하는수용체에결합하는데필수적인부분이며 AA 부분이결합을더강화하여 B형및 D형간염바이러스의리간드역할을하여감염을일으킨다고보고하였으며 (2) 2012 년도에드디어특정단백질에결합하는단백질들을정제해내는기술인 TAP (Tandem affinity purification) 을이용하여 HBV의 Pre-S1 도메인과직접적으로결합하는숙주세포의수용체인 NTCP를규명하게된다 (Fig. 2) (11). 더나아가 NTCP 수용체가종특이적으로 HBV 감염을유발하는특징을설명하기위해 HBV pre-s1 도메인과직접적으로결합하는 NTCP 수용체의필수적인부분 (AA ) 과 HBV 감염을유도하는서열 (AA 84-87) 을분석한결과, 사람의 NTCP (hntcp) 수용체의경우는두시퀀스가모두존재하지만마우스 NTCP의경우에는 AA84-87 부분의결핍되어있음을확인하였다 (3, 11~13). NTCP의구조와기능 Solute carrier (SLC) 는세포막의운송을담당하는단백질로총 52 패밀리를구성하는 300가지의유전자로구성되어있으며특히담즙산의운송을담당하는 SLC10 패밀리 (SLC-10A1~7) 중 SLC10A1 유전자에의해 hntcp가만들어진다 (14). 현재 NTCP의구조가완전하게밝혀지지는않았으나주로간세포의기저막에분포하는당단백질로서 hntcp의경우 349개의아미노산으로구성되어있으며질량은 56 kda이다 (3). NTCP 는 7~9 개의세포막을통과하는도메인을가지고있는것으로추정되며 NTCP의 N 말단부위는세포막바깥쪽에 C 말단부위는세포막안쪽에위치해있다 (15, 16). NTCP는 2개의 sodium ion과 1개의담즙산인 taurocholate 와결합하는폴리펩타이드이다. NTCP 수용체는주로간세포에서 sodium ion 의존적으로담즙산을흡수하는세포수용체의역할 (17) 과 HBV의 pre-s1 도메인과결합하여간염바이러스의유입통로를제공하는역할을한다. 이는 hntcp가 HBV의 pre-s1 도메인과결합하였을때 taurocholate 의흡수가저해되고몇 NTCP 기질들에의해 HBV

4 338 S-Y Kim, et al. Figure 2. Hepatitis B virus S protein structure. (A) HBsAg consists of three surface proteins. The small S antigen has only S domain and the middle S antigen harbors pres2 and S domains. The large S antigen contains pres1, pres2, and S domains. (B) Schematic structure of pres1-s2 domains. pres1 domain amino acids 2-77 are necessary for viral infection. Among amino acid 2-48, amino acid 9-18 are essential binding sites of HBsAg for NTCP receptor of human hepatocyte, and amino acid are accessory parts. Both pres1 and pres2 domains are important for virion formation. 의간세포내로의진입이저해되는것을통해이두가지기능을하는 NTCP 의부분이서로독립적이지않음을연구결과로서입증된바있다 (11, 17). NTCP 발현세포주및한계 HBV의숙주세포로의진입과정에서 NTCP 수용체의역할을증명하기위해 sirna를이용하여 NTCP의발현을억제시킨 PHH (18) 실험에서 HBV 감염률이 30~50% 정도줄어드는것을확인하였다 (19). 이처럼 NTCP 를발현시킨세포주에서는 HBV 감염률이 50~70% 정도로비교적높게나타난반면 NTCP 발현이약한 HepG2, Huh7 세포나간세포주가아닌 HeLa 세포에서는감염이거의나타나지않았다. 하지만 lipofectamine 을이용하여 hntcp 유전자를사람의간세포에형질주입시킨결과 hntcp- HepG2, hntcp-hun7 세포는 HepG2, Huh7 세포와비교하였을때 HBV 감염효율이 PHH와비슷할정도로높게나타남을확인하였다 (5). 또한 HepG2 세포에 DMSO를처리하였을때세포질내 DNA가증가한다는이전결과를토대로 (20) 실험한결과 hntcp-hepg2 세포를 2% 의 DMSO가첨가된배지에배양하면 HBV 감염정도가 10% 이하이나 DMSO를 2.5~ 3% 로증가시킨배지에서는감염효율이 50~70% 정도로상승됨이관찰되었다 (5, 11). 이처럼 hntcp-hepg2, hntcp-huh7 의형질주입전에 DMSO를처리하였을경우 hntcp 와의결합을통한 HBV 감염효율이높아질수있다. 이러한결과를통해 DMSO 가세포에발현되는 NTCP 의양, NTCP 의세포막에서의발현위치, NTCP의 posttranslational modification 에영향을준다는것을추측할수있다. 하지만 DMSO 증가에따른 NTCP와 HBV의결합에의한감염효율증대와관련된정확한메커니즘은아직밝혀진바가없어서더많은연구가필요하다. 지금까지살펴본바와같이형질주입을통해 hntcp 를발현시키는실험이사람의간세포에서만진행된것은 Hepa1-6, MMHD3 과같은마우스세포주에서는 hntcp 유전자를인위적으로발현시켜도 hntcp-hepg2, hntcp- Huh7에서관찰되는수준의 HBV 감염이나타나지않기

(B) Schematic drawing of HBs domain of Homo sapiens, macaca fascicularis and mus musculus. Amino acid full sequence of Homo sapiens is in discord with that of macaca fascicularis and mus musculus.

5 NTCP, the Receptor for HBV 339 Figure 3. NTCP amino acid sequence homology between human and other species. (A) Identities and Homologies come from protein sequence Homo sapiens against Crab eating monkey, Rattus norvegicus and Mus musculus. (B) Schematic drawing of HBs domain of Homo sapiens, macaca fascicularis and mus musculus. Amino acid full sequence of Homo sapiens is in discord with that of macaca fascicularis and mus musculus. Amino acid of macaca facicularis and amino acid of mus musculus are different from Homo sapiens amino acids. 때문이다 (12). 또한, 마우스로부터얻은 mntcp 를사람의간세포에발현시키면 HBV의 pre-s1 도메인에결합을하지만바이러스의감염이나타나지는않으며이는 mntcp 의 아미노산서열이 hntcp 와다르기때문이다. 반면, 게먹이원숭이로부터얻은 mkntcp 는 HBV의 pres1 도메인에결합조차하지않는다 (Fig. 3). 또한간세포가아닌 HeLa 세포에서도 hntcp 의과발현이 HBV의숙주세포감염효율을올릴수없음이확인되었다 (13). 이러한결과를통해 HBV가숙주세포로진입하는단계에서 NTCP 가중요한역할을하기위해서는사람의간세포에서만특이적으로존재하는또다른주된요소가필요하다는것을예상할수있다. 최근연구에따르면 Glypican-5 와 heparin sulfate 의일부분이 HBV와 hepatitis D virus (HDV) 의숙주세포로의진입시 NTCP 와함께중요한역할을한다고보고되었으며 Glypican-5 의발현을저해하였을때 HBV의복제시에분비되는 HBsAg과 HBV pgrna 의양이감소됨을확인한바있다 (Fig. 4) (21). 현재까지밝혀진 hntcp를발현하는세포주들에대한 HBV 감염의효율은 50~70% 정도로낮기때문에 HBV 감염의효율을높이기위해서는 NTCP 이외의또다른수용체나다른요소들에대한연구가절실하게요구된다. HBV 실험에사용되는동물모델과한계점기존에 HBV 감염연구를위한마우스모델의경우유체역학의원리를이용한주입모델 (hydrodynamic injection), 인간화마우스모델, HBV 유전자형질전환마우스모델등이주로사용되어왔다. Hydrodynamic 모델은면역능력 Figure 4. Schematic representation of the hepatitis B virus attachment. Heparan sulfate proteoglycan (HSPG) and Glypican5 (GPC5) help pre-s1 domain of HBsAg attach to NTCP receptor expressed in the surface of human hepatocyte. 을갖는마우스에 hydrodynamic injection 방법으로 HBV 의 super-genomic DNA 를주입하여급성 HBV 를유도하는동 물모델이다. 이모델에서는마우스무게의 10% 에해당 하는 DNA 를꼬리정맥에 4~7 초내로빠르게주입을하 면주입된유전자가 90% 는간에서나머지 10% 정도는 간이외기관에서발현을한다 (22, 23). 인간화마우스 모델은사람의간세포를분리해서 upa-scid 마우스의 간에이식을하는모델이다. 이 upa-scid 마우스는면역 력이결핍된 SCID 마우스와 urokinase-type plasminogen activator transgenic mouse 를교배시켰기때문에 hntcp 를 발현한다고알려진 PHH 를마우스의간에이식하여도 면역거부반응없이 HBV 감염이유도된다 (24). 또한

6 340 S-Y Kim, et al. upa-scid 마우스에서혈청의알부민수치를관찰하여사람의간세포가마우스의간에서잘정착하여증식하고있는지확인할수있으며본마우스의 HBV life cycle이사람과동일하게구현되어현재 HBV 감염모델로도많이활용되고있다 (25). HBV의 DNA를포함하는형질전환마우스는 HBV 발병메커니즘에대한정보를제공하고바이러스복제를억제시키는항바이러스제효과를관찰할수있는모델로유용하게활용될수있으나바이러스의진입단계와전파단계를확인할수없다 (26). 이러한마우스모델들은감염과정을정확히관찰할수없거나면역반응이없는상태에서의감염만을확인할수있는한계를지니고있다. 이러한한계를극복하기위해 hntcp를발현하는형질전환마우스가제작되었지만 hntcp에바이러스가결합하여 HDV 감염이나타나지만 HBV 감염이나타나지않는다 (27). HBV는 hntcp에결합을하나 HBV 감염에있어종특이적인특징으로마우스의간세포에는존재하지않지만사람의간세포에존재하는보조인자들이추가적으로필요한것으로판단되며이러한보조인자의규명이실질적인동물모델구축에필요할것이다 (13). NTCP 저해제현재까지밝혀진대표적인 NTCP 저해제로는 myrcludex B, cyclosporin A 등이있다. Myrcludex B는 HBV의감염에필수적인 pre-s1 도메인의미리스토일화된 2-28번아미노산으로부터유래되어합성된지질펩타이드이다. Myrcludex B는 HBV의 pre-s1 도메인과경쟁적으로 hntcp에결합하여 HBV의숙주세포내로의진입및감염을저해하며약 100 pm의낮은 IC 50 농도를나타낸다. 또한 upa- SCID 마우스가 HBV에감염되기전에 myrcludex B를주입해주면 HBcAg 생성이효과적으로저해될뿐아니라 HBV 복제와 cccdna의생성도억제된다고보고되었으며 (25) 현재유효성과안전성을검증하기위한 phase Ib/IIa 임상시험이진행중이다 (28). Cyclosporin A는 T 세포활성에중요한칼시뉴린의활동을억제하는면역억제제로알려져있다. 2013년도에밝혀진연구결과에따르면 cyclosporin A가 NTCP와결합하는 HBV의 pre-s1 도메인과경쟁이가능하며 8 μm의 cyclosporin A에서가장효율적으로결합을억제함이확인되었다 (29). hntcp-hepg2 세포에 cyclosporin A와 myrcludex B를병용처리시두약물이경쟁적으로작용하는데이는 Myrcludex B와 cyclosporin A가결합하는 NTCP 부분이서로일치함을보여준 다 (29). NTCP의기질로알려진 estrone-3-sulfate, dehydroepiandrosterone (DHEAS), bromosulphthalein 와같은 steroidal hormone, taurocholate, taurourosodeoxycholate는 hntpc-hepg cell, hntpc-huh7cell에서 HBV 감염과동시에처리하였을때 hntcp에경쟁적으로결합하여 HBV의진입과정을억제하며이는 hntcp에의한 taurocholate uptake가줄어드는것을통해확인되었다 (29). HBV 감염환자들에게간기능향상을위해사용되는 ursodeoxycholic acid (UDCA) 는 hntcp를과발현시킨간세포에처리하였을때또한 taurocholate uptake의감소하는것을확인하여잠재적으로 HBV 감염진입을막는항바이러스제로개발가능할것이다 (30). HepG2, Huh7 cell에 hntcp를과발현한세포주를이용하면 NTCP를치료타켓으로작용하는화합물들을대량스크리닝하는데유용하며최근에이방법으로 Oxysterol 계열의화합물들이 NTCP에결합하여 HBV의감염을억제할것이라는연구가보고된바있다 (5). DISCUSSION HBV는급, 만성간염, 간섬유화, 간경변및간암의주원인으로 IFN, nucleos(t)ide 계열의항바이러스제와백신이개발되면서 HBV로인한유병률과사망률이일부감소하고있다. 그러나여전히이러한치료제가인체내감염된 HBV의복제를저해할뿐완전히제거하지못하는한계점으로인하여장기간투여에따른각종내성과부작용이보고되고있다. 따라서기존치료제의한계를극복하고 HBV 치료효과를극대화하기위해서는 HBV의간세포안으로의진입을억제하는치료제및백신의개발이매우시급한실정이다. 2012년도에 HBV가숙주세포로진입하는데필수적인역할을하는 NTCP 수용체가처음규명되었으나 NTCP에대한짧은연구기간, 실제적인바이러스감염이 hntcp와의결합을통해서만발생하는점, 동물모델을원활하게확보할수없는점등의어려움으로인해현재까지효과적인 HBV 진입억제제로서의치료제개발이제대로이루어지지못하고있다. 이러한상황에서무엇보다필요한것은이런과정에관여하는 NTCP 이외의다른수용체나요소들을발견하기위한노력이다. 현재까지의연구결과들은 NTCP 결합만으로는바이러스감염이이루어질수

7 NTCP, the Receptor for HBV 341 없으며사람세포에서는이의 endocytosis의촉진등의역할을수행하는인자들이있음을시사하고있다. 이러한연구결과들이뒷받침되면기존한계점을극복한동물모델에서다양한 HBV에대한연구가가능할것이다. 더나아가 NTCP와결합하여바이러스의진입과정을차단할수있는새로운기전의항바이러스제의개발을기대해볼수있다. REFERENCES 1) Global Burden of Disease Study 2010 outlines present and future health priorities, both nationally and internationally. Br J Hosp Med (Lond) 2013;74:71. 2) Glebe D, Urban S, Knoop EV, Cag N, Krass P, Grun S, et al. Mapping of the hepatitis B virus attachment site by use of infection-inhibiting pres1 lipopeptides and tupaia hepatocytes. Gastroenterol 2005;129: ) Watashi K, Urban S, Li W, Wakita T. NTCP and beyond: opening the door to unveil hepatitis B virus entry. Int J Mol Sci 2014;15: ) Dienstag JL. Hepatitis B virus infection. N Engl J Med 2008;359: ) Iwamoto M, Watashi K, Tsukuda S, Aly HH, Fukasawa M, Fujimoto A, et al. Evaluation and identification of hepatitis B virus entry inhibitors using HepG2 cells overexpressing a membrane transporter NTCP. Biochem Biophys Res Commun 2014;443: ) Wieland S, Thimme R, Purcell RH, Chisari FV. Genomic analysis of the host response to hepatitis B virus infection. Proc Natl Acad Sci U S A 2004;101: ) Urban S, Bartenschlager R, Kubitz R, Zoulim F. Strategies to inhibit entry of HBV and HDV into hepatocytes. Gastroenterol 2014;147: ) Zoulim F, Locarnini S. Optimal management of chronic hepatitis B patients with treatment failure and antiviral drug resistance. Liver Int 2013;33 Suppl 1: ) Zoulim F, Perrillo R. Hepatitis B: reflections on the current approach to antiviral therapy. J Hepatol 2008;48 Suppl 1: S ) Neurath AR, Kent SB, Strick N, Parker K. Identification and chemical synthesis of a host cell receptor binding site on hepatitis B virus. Cell 1986;46: ) Ni Y, Lempp FA, Mehrle S, Nkongolo S, Kaufman C, Falth M, et al. Hepatitis B and D viruses exploit sodium taurocholate co-transporting polypeptide for species-specific entry into hepatocytes. Gastroenterology 2014;146: ) Elinger S. HBV: Stowaway of NTCP. Clin Res Hepatol Gastroenterol 2014;38: ) Yan H, Peng B, He W, Zhong G, Qi Y, Ren B, et al. Molecular determinants of hepatitis B and D virus entry restriction in mouse sodium taurocholate cotransporting polypeptide. J Virol 2013;87: ) Hagenbuch B, Meier PJ. Molecular cloning, chromosomal localization, and functional characterization of a human liver Na+/bile acid cotransporter. J Clin Invest 1994;93: ) Meier PJ, Stieger B. Bile salt transporters. Annu Rev Physiol 2002;64: ) Anwer MS, Stieger B. Sodium-dependent bile salt transporters of the SLC10A transporter family: more than solute transporters. Pflugers Arch 2014;466: ) Yan H, Peng B, Liu Y, Xu G, He W, Ren B, et al. Viral entry of hepatitis B and D viruses and bile salts transportation share common molecular determinants on sodium taurocholate cotransporting polypeptide. J Virol 2014;88: ) Glebe D, Urban S. Viral and cellular determinants involved in hepadnaviral entry. World J Gastroenterol 2007;13: ) Yan H, Zhong G, Xu G, He W, Jing Z, Gao Z, et al. Sodium taurocholate cotransporting polypeptide is a functional receptor for human hepatitis B and D virus. Elife 2012;1: e ) Gripon P, Diot C, Corlu A, Guguen-Guillouzo C. Regulation by dimethylsulfoxide, insulin, and corticosteroids of hepatitis B virus replication in a transfected human hepatoma cell line. J Med Virol 1989;28: ) Verrier ER, Colpitts CC, Bach C, Heydmann L, Weiss A, Renaud M, et al. A targeted functional RNA interference screen uncovers glypican 5 as an entry factor for hepatitis B and D viruses. Hepatol 2016;63: ) Huang LR, Wu HL, Chen PJ, Chen DS. An immunocompetent mouse model for the tolerance of human chronic hepatitis B virus infection. Proc Natl Acad Sci U S A 2006; 103: ) Yang PL, Althage A, Chung J, Chisari FV. Hydrodynamic injection of viral DNA: a mouse model of acute hepatitis B virus infection. Proc Natl Acad Sci U S A 2002;99:

8 342 S-Y Kim, et al ) Tateno C, Yoshizane Y, Saito N, Kataoka M, Utoh R, Yamasaki C, et al. Near completely humanized liver in mice shows human-type metabolic responses to drugs. Am J Pathol 2004;165: ) Volz T, Allweiss L, Ben MM, Warlich M, Lohse AW, Pollok JM, et al. The entry inhibitor Myrcludex-B efficiently blocks intrahepatic virus spreading in humanized mice previously infected with hepatitis B virus. J Hepatol 2013; 58: ) Raney AK, Kline EF, Tang H, McLachlan A. Transcription and replication of a natural hepatitis B virus nucleocapsid promoter variant is regulated in vivo by peroxisome proliferators. Virol 2001;289: ) Li N, Zhang P, Yang C, Zhu Q, Li Z, Li F, et al. Association of genetic variation of sodium taurocholate cotransporting polypeptide with chronic hepatitis B virus infection. Genet Test Mol Biomarkers 2014;18: ) Warner N, Locarnini S. The new front-line in hepatitis B/D research: identification and blocking of a functional receptor. Hepatol 2013;58: ) Nkongolo S, Ni Y, Lempp FA, Kaufman C, Lindner T, Esser-Nobis K, et al. Cyclosporin A inhibits hepatitis B and hepatitis D virus entry by cyclophilin-independent interference with the NTCP receptor. J Hepatol 2014;60: ) Chen W, Liu J, Gluud C. Bile acids for viral hepatitis. Cochrane Database Syst Rev 2003;CD

Pharmacotherapeutics Application of New Pathogenesis on the Drug Treatment of Diabetes Young Seol Kim, M.D. Department of Endocrinology Kyung Hee Univ

Pharmacotherapeutics Application of New Pathogenesis on the Drug Treatment of Diabetes Young Seol Kim, M.D. Department of Endocrinology Kyung Hee Univ Application of New Pathogenesis on the Drug Treatment of Diabetes Young Seol Kim, M.D. Department of Endocrinology Kyung Hee University College of Medicine & Hospital E mail : ycell2@yahoo.co.kr Abstract