• BMB Reports
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• 제55권10호
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• pp.481-487
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• 2022

Over the past few years, hydrogen sulfide (H₂S) has been shown to exert several biological functions in mammalian. The endogenous production of H₂S is mainly mediated by cystathione β-synthase, cystathione γ-lyase and 3-mercaptopyruvate sulfur transferase. These enzymes are broadly expressed in liver tissue and regulates liver function by working on a variety of molecular targets. As an important regulator of liver function, H₂S is critically involved in the pathogenesis of various liver diseases, such as non-alcoholic steatohepatitis and liver cancer. Targeting H₂S-generating enzymes may be a therapeutic strategy for controlling liver diseases. This review described the function of H₂S in liver disease and summarized recent characterized role of H₂S in several cellular process of the liver.

• 생명과학회지
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• 제25권2호
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• pp.223-230
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• 2015

RCAN1은 calcineurin을 억제하는 내인성 단백질로 calcineurin-NFATc1 신호전달 경로와 관련된 질환의 병인에 중요한 역할을 담당한다. 특히 RCAN1-4 아형 유전자의 경우 NFATc1 전사인자에 의해 조절된다. RANKL 자극은 calcineurin-NFATc1 경로로 파골세포 분화를 유도하는데, RCAN1과 파골세포의 분화에 관련된 연구는 보고 된 바 없다. 따라서 본 연구는 RANKL 처리에 의해 파골세포 분화가 유도될 때 RCAN1이 calcineurin-NFATc1 경로에 미치는 영향을 in vitro에서 조사했다. 마우스로부터 분리한 골수단핵세포에 RANKL을 처리하여 파골세포 분화를 유도했다. RANKL 처리 후 조사 대상 유전자의 mRNA 발현과 단백질 발현을 각각 RT-PCR과 Western blot로써 측정했다. 마우스 RCAN1-4 vector를 파골전구세포인 RAW 264.7 단핵세포주와 골수단핵세포에 형질도입(transfection)시켜 RCAN1-4 유전자의 과발현을 유도했다. 형질도입 후 파골세포 분화의 형태적 변화는 TRAP 염색을 통해 관찰했다. RANKL 처리 후 NFATc1, calcineurin, RCAN1-4 mRNA 발현은 크게 증가했다. 단백질 발현의 경우 NFATc1과 RCAN1은 증가했으나 calcineurin은 대조군과 차이가 없었다. RCAN1-4 유전자의 과발현 유도 시 RCAN1-4 mRNA는 크게 증가되었으나 RCAN1 단백질 발현은 증가되지 않았다. 특히 RANKL 존재 시 RCAN1 유전자를 knock-down시켜도 RCAN1 발현은 정상적으로 유지되었다. 한편, NFATc1 발현은 과발현 유도시 감소했고 knock-down 유도 시 증가하는 경향을 보였다. RCAN1-4 유전자 과발현을 유도한 골수단핵세포에서 배양 5일 후 파골세포 분화는 대조군과 차이가 없었다. 이러한 결과는 RANKL에 의한 파골세포 분화 시 RCAN1이 calcineurin-NFATc1 경로를 통해 파골세포 분화에 미치는 영향은 제한적일 것으로 사료된다.

• Molecules and Cells
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• 제27권1호
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• pp.15-19
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• 2009

Notch signaling is controlled at multiple levels. In particular, stabilized Notch receptor activation directly affects the transcriptional activations of Notch target genes. Although some progress has been made in terms of defining the regulatory mechanism that alters Notch stability, it has not been determined whether Notch1/NICD stability is regulated by $GSK-3{\alpha}$. Here, we show that Notch1/NICD levels are significantly regulated by $GSK-3{\beta}$ and by $GSK-3{\alpha}$. Treatment with LiCl (a specific GSK-3 inhibitor) or the overexpression of the kinase-inactive forms of $GSK-3{\alpha}/{\beta}$ significantly increased Notch1/NICD levels. Endogenous NICD levels were also increased by either $GSK-3{\alpha}/{\beta}$- or $GSK-3{\alpha}$-specific siRNA. Furthermore, it was found that $GSK-3{\alpha}$ binds to Notch1. Deletion analysis showed that at least three Thr residues in Notch1 (Thr-1851, 2123, and 2125) are critical for its response to LiCl, which increased not only the transcriptional activity of endogenous NICD but also Hes1 mRNA levels. Taken together, our results indicate that $GSK-3{\alpha}$ is a negative regulator of Notch1/NICD.

• 생명과학회지
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• 제19권11호
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• pp.1506-1513
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• 2009

RGS단백질은 G 단백질 신호전달작용에 있어서 신호를 억제하는 조절단백질로서 G 단백질 매개수용체(GPCR)의 활성을 억제하는 것으로 알려졌다. 그렇지만 캐너비노이드 수용체 CB2의 활성에 있어서 RGS 단백질의 조절효과에 관해서는 지금까지 알려져 있지 않다. 그러므로 본 연구에서 우리는 RGS2, 3, 4, 5와 캐너비노이드 수용체 CB2 cDNA를 동시에 HEK293 세포주에 발현시킨 후 각 RGS 단백질의 효과를 조사하였다. CB2 단백질을 발현하는 HEK293 세포주(CB2-HEK293)에서 CB2 효현제인 WIN55,212-2는 폴스콜린으로 유도된 cAMP response element (CRE) 활성을 억제하였다. 이러한 WIN55,212-2의 CRE 억제 활성은 RGS3에 의하여 차단되었지만 RGS2, 4, 및 RGS5에서는 관찰되지 않았다. 뿐만 아니라 RGS3 small interference RNA (siRNA)를 사용하여 내인성 RGS3 단백질의 발현을 저하시키면 WIN55,212-2에 의한 폴스콜린 유도 CRE 억제활성은 더욱 증강되었다. 이상의 결과는 캐너비노이드 수용체 CB2 신호전달작용에 있어서 RGS 단백질의 기능적 역할과 특히 내인성 RGS3의 캐너비노이드 수용체 CB2에 대한 선택적 작용을 나타낸다.

• BMB Reports
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• 제48권5호
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• pp.249-255
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• 2015

PTPRT/RPTPρ is the most recently isolated member of the type IIB receptor-type protein tyrosine phosphatase family and its expression is restricted to the nervous system. PTPRT plays a critical role in regulation of synaptic formation and neuronal development. When PTPRT was overexpressed in hippocampal neurons, synaptic formation and dendritic arborization were induced. On the other hand, knockdown of PTPRT decreased neuronal transmission and attenuated neuronal development. PTPRT strengthened neuronal synapses by forming homophilic trans dimers with each other and heterophilic cis complexes with neuronal adhesion molecules. Fyn tyrosine kinase regulated PTPRT activity through phosphorylation of tyrosine 912 within the membrane-proximal catalytic domain of PTPRT. Phosphorylation induced homophilic cis dimerization of PTPRT and resulted in the inhibition of phosphatase activity. BCR-Rac1 GAP and Syntaxin-binding protein were found as new endogenous substrates of PTPRT in rat brain. PTPRT induced polymerization of actin cytoskeleton that determined the morphologies of dendrites and spines by inhibiting BCR-Rac1 GAP activity. Additionally, PTPRT appeared to regulate neurotransmitter release through reinforcement of interactions between Syntaxin-binding protein and Syntaxin, a SNARE protein. In conclusion, PTPRT regulates synaptic function and neuronal development through interactions with neuronal adhesion molecules and the dephosphorylation of synaptic molecules. [BMB Reports 2015; 48(5): 249-255]

• IMMUNE NETWORK
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• 제8권1호
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• pp.1-6
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• 2008

Apoptosis signal-regulating kinase 1 (ASK1), a mitogen- activated protein kinase kinase kinase, plays pivotal roles in stress responses. In addition, ASK1 has emerged as a key regulator of immune responses elicited by pathogen-associated molecular patterns (PAMPs) and endogenous danger signals. Recent studies have demonstrated that reactive oxygen species (ROS)-dependent activation of ASK1 is required for LPS-stimulated cytokine production as well as extracellular ATP-induced apoptosis in immune cells. The mechanism of ROS-dependent regulation of ASK1 activity by thioredoxin and TRAFs has been well characterized. In this review, we focus on the molecular details of the activation of ASK1 and its involvement in innate immunity.

• The Korean Journal of Physiology
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• 제20권2호
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• pp.175-183
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• 1986

Since it was proposed that vanadate may be an ‘ideal endogenous regulator of the $Na^+,\;K^+-ATPase$ activity (Cantley et at, 1979), vanadate has been a subject of intensive research and a variety of its physiological effects have been described (Nechay, 1984). In isolated guinea pig heart muscle vanadate shows a positive inotropic effect on ventricular muscle, while it induces a negative inotropic effect on atrial muscle. But its underlying mechanism has not been elucidated so far. Therefore, in this study the flux rates of calcium ion into and from guinea pig heart muscle were measured to throw some light on the underlying mechanism, because those rates have been known to be closely related to the cardiac contractility and the results are summarized as follows: 1) Calcium efflux rates from the intracellular $Ca^{++}$ pool (compartment 4) of both guinea pig left atrium and right ventricle were significantly reduced by vanadate and their pool sizes were significantly increased by vanadate. 2) The magnitude of calcium influx into left atrium was reduced by vanadate, While the magnitude of calcium influx into right ventricle was not affected by vanadate. From these results, it may be concluded that the positive inotropic effect of vanadate on the ventricular muscle was due to a reduced efflux rate of calcium ion and its negative inotropic effect on atrial muscle was resulted from a reduced influx of calcium ion.

• IMMUNE NETWORK
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• 제19권1호
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• pp.1.1-1.13
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• 2019

Systemic lupus erythematosus (SLE) is the prototypic systemic autoimmune disease characterized by production of autoantibodies to various nuclear antigens and overexpression of genes regulated by IFN-I called IFN signature. Genetic studies on SLE patients and mutational analyses of mouse models demonstrate crucial roles of nucleic acid (NA) sensors in development of SLE. Although NA sensors are involved in induction of antimicrobial immune responses by recognizing microbial NAs, recognition of self NAs by NA sensors induces production of autoantibodies to NAs in B cells and production of IFN-I in plasmacytoid dendritic cells. Among various NA sensors, the endosomal RNA sensor TLR7 plays an essential role in development of SLE at least in mouse models. CD72 is an inhibitory B cell co-receptor containing an immunoreceptor tyrosine-based inhibition motif (ITIM) in the cytoplasmic region and a C-type lectin like-domain (CTLD) in the extracellular region. CD72 is known to regulate development of SLE because CD72 polymorphisms associate with SLE in both human and mice and CD72^-/- mice develop relatively severe lupus-like disease. CD72 specifically recognizes the RNA-containing endogenous TLR7 ligand Sm/RNP by its extracellular CTLD, and inhibits B cell responses to Sm/RNP by ITIM-mediated signal inhibition. These findings indicate that CD72 inhibits development of SLE by suppressing TLR7-dependent B cell response to self NAs. CD72 is thus involved in discrimination of self-NAs from microbial NAs by specifically suppressing autoimmune responses to self-NAs.

• Journal of Gastric Cancer
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• 제6권3호
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• pp.132-138
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• 2006

목적: 도파민은 중추신경전달물질이지만 위장관에서 도파민수용체와 결합하여 점막상피세포 증식, 상피세포의 보호, 위암 세포증식과 관련이 있는 것으로 알려져 있다. 본 연구에서는 위암에서 기원한 세포주를 이용하여 도파민과 각각의 도파민 수용체가 위암 세포 증식과 억제에 작용하는 역할에 대해 알아보았다. 대상 및 방법: 위암세포기원에서 각각 유래한 세포주인 SNU601과 KCU-C2를 이용하여 RNA 추출 후 RT-PCR 시행 후 도파민수용체 D1, D2L과 D2S 각각에 대한 primer로 PCR을 시행하여 수용체 유전자의 상대적인 발현정도를 측정하였다. 도파민과 Dl 수용체의 대항제인 SCH 23390과 D2 수용체 대항제인 raclopride를 사용하여 약물처리에 따른 위암세포주에서 세포 증식에 대한 분석을 하였다. 결과: KCU-C2 세포주에서 D1과 D2L과 D2S 유전자 mRNA의 상대적인 발현정도는 모두 높은 발현을 보였지만, SNU 601 세포주에는 mRNA의 발현이 모두 낮은 수준이었으며, 특히 D2L mRNA는 발현되고 있지 않았다. 약물처리에 따른 위암세포주에서 세포증식에 대한 분석에서는 D1과 D2S 수용체를 통한 도파민의 신호는 세포의 증식을 억제하였고 D2L 수용체를 통한 도파민의 신호는 세포의 증식을 유도하였다. 결론: 본 연구를 통해 도파민이 위암의 세포증식과 억제에 관여하며, 도파민의 이러한 효과는 도파민의 신호가 어느 수용체를 통해 전달되었느냐에 따라 위암세포의 증식과 억제가 이루어짐을 알 수 있었다.

• KSBB Journal
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• 제30권6호
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• pp.313-318
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• 2015

${\delta}$-Aminolevulinic acid (ALA) is an endogenous metabolite formed in the mitochondria from succinyl-CoA and glycine, and plays a key role in the living body as an intermediate of the compound in the porphyrin biosynthesis pathway. ALA has been commonly used in photodynamic therapy for several years, because ALA is of interest as a biodegradable mediator, a growth regulator, and an effective agent used in dermatology. Here, we determined which ALA derivatives were the most effective for the inhibition of the cell proliferation and growth of human fibroblast. As a result, we found that the treatment of ALA derivatives including ALA, ALAP (ALA phosphate salt), MAL (Methyl 5-aminolevulinate hydrochloride salt), PBGL (phophobilinogen lactam) and PBGH (phophobilinogen-HCl) could attenuate cell proliferation of human fibroblast cells. Among them, PBGH was the most effective derivative. In addition, PBGH treatment could induce mitochondrial membrane depolarization, leading to cell death of human fibroblast. These results suggest that mitochondrial membrane depolarization induced by ALA and PBGH treatment might be responsible for inhibition of cell proliferation and death. Taken together, our results propose the possibility that PBGH can be used as one of the effective drugs in human skin disease, psoriasis.