• Journal of Microbiology
• /
• 제44권4호
• /
• pp.461-465
• /
• 2006

The occurrence of thioredoxin reductase (NAD(P)H: oxidized-thioredoxin reductase, EC 1.6.4.5, TrxR) in five mesophilic species of Deinococcus was investigated by PAGE. Each species possessed a unique TrxR pattern, for example, a single TrxR characterized D. radiopugnans while multiple forms of TrxR occurred in other Deinococcal spp. Most of TrxRs occurring in Deinococcus showed dual cofactor specificity, active with either NADH or NADPH, although the NADPH specific-TrxR was observed in D. radiophilus and D. proteolytic us.

• 생명과학회지
• /
• 제32권1호
• /
• pp.63-69
• /
• 2022

Thioredoxin reductase (TrxR) 시스템은 세포 내 산화 환원 반응의 항상성 유지와 신호 전달 경로를 조절하는데 중추적인 역할을 함으로써 세포의 생존과 기능 유지에 필수적이다. TrxR 시스템은 thioredoxin (Trx), TrxR 및 nicotinamide adenine dinucleotide phosphate의 구성요소를 포함하며, TrxR 효소의 촉매 반응에 의해 환원된 Trx는 하위 표적 단백질을 환원시켜 결과적으로 산화적 스트레스에 대한 방어와 세포 분화, 성장 및 사멸을 조절한다. 암세포는 무한한 세포 증식과 높은 대사율로 인해 과도하게 생성된 활성산소종을 소거하기 위해 세포 내 항산화능을 향상시켜 세포의 생존을 유지하는 반면, 항산화 시스템에 대한 의존도 및 민감도가 높아 이를 표적으로 한 항암 활성 연구에서 잠재적인 가능성이 있음을 제시한다. 여러 연구 결과에서 TrxR이 다양한 유형의 암에서 높은 수준으로 발현되고 있음이 밝혀졌고, 또한 TrxR 시스템을 표적으로 한 항암 활성에 대한 연구가 증가하고 있다. 따라서 본 총설에서는 세포 내 TrxR 시스템의 기능과 암의 발달 및 진행에서의 역할을 다루고, TrxR 억제제의 항암 활성 및 기전을 검토함으로써 항암 활성 연구에 대한 전략으로 TrxR 시스템의 타당성과 가치를 논하였다.

• Molecules and Cells
• /
• 제22권1호
• /
• pp.113-118
• /
• 2006

Thioredoxin reductase (TrxR), a component of the redox control system involving thioredoxin (Trx), is implicated in defense against oxidative stress, control of cell growth and proliferation, and regulation of apoptosis. In the present study a stable transfectant was made by introducing the vector pcDNA3.0 harboring the fission yeast TrxR gene into COS-7 African green monkey kidney fibroblast cells. The exogenous TrxR gene led to an increase in TrxR activity of up to 3.2-fold but did not affect glutathione (GSH) content, or glutaredoxin and caspase-3 activities. Levels of reactive oxygen species (ROS), but not those of nitric oxide (NO), were reduced. Conversely, 1-chloro-2,4-dinitrobezene (CDNB), an irreversible inhibitor of mammalian TrxR, enhanced ROS levels in the COS-7 cells. After treatment with hydrogen peroxide, the level of intracellular ROS was lower in the transfectants than in the vector control cells. These results confirm that TrxR is a crucial determinant of the level of cellular ROS during oxidative stress as well as in the normal state.

• Journal of Microbiology
• /
• 제44권1호
• /
• pp.35-41
• /
• 2006

The unique gene encoding thioredoxin reductase (TrxR) was previously cloned and characterized from the fission yeast Schizosaccharomyces pombe, and its expression was induced by oxidative stress. To elucidate tbe regulatory mechanism of the S. pombe TrxR gene, three fusion plasmids were generated using polymerase chain reaction: pYUTR20, pYUTR30, and pYUTR40. Plasmid pYUTR20 has an upstream region of 891 base pairs, pYUTR30 has 499 in this region, and pYUTR40 has an 186 bp upstream region. Negatively acting sequence is located between $-1,526\;\~\;-891bp$ upstream of the gene. The upstream sequence, responsible for the induction of TrxR by menadione (MD), is situated on the $-499\;\~\;-186bp$ region, which is also required for TrxR induction by mercuric chloride. The same region also appeared to be required for Pap1-mediated transcriptional regulation of the TrxR gene, which contains the two plausible Papl binding sites, TTACGAAT and TTACGCGA. Consistently, basal and inducible expression of the TrxR gene was markedly lower in the Pap1-negative TP108-3C cells than in wild-type yeast cells. In summary, up-regulation of the S. pombe TrxR gene is mediated by Pap1 via the transcriptional motif(s) located on the $-499\;\~\;-186bp$ region.

• 한국결정학회:학술대회논문집
• /
• 한국결정학회 2003년도 춘계학술연구발표회
• /
• pp.18-18
• /
• 2003

Thioredoxin (Trx) is a small redox protein that is ubiquitously distributed from achaes to human. In diverse organisms, the protein is involved in various physiological roles by acting as electron donor and regulators of transcription and apoptosis as well as antioxidants. Sequences of Trx within various species are 27～69% identical to that of E. coli and all Trx proteins have the same overall fold, which consists of central five β strands surrounded by four α helices. The N-terminal cysteine in WCGPC motif of Trx is redox sensitive and the motif is highly conserved. Compared with general cysteine, the N-terminal cysteine has low pKa value. The result leads to increased reduction activity of protein. Recently, novel thio.edoxin-related protein (TRP14) was found from rat brain. TRP14 acts as disulfide reductase like Trx1, and its redox potential and pKa are similar to those of Trx1. However, TRP14 takes up electrons from cytosolic thioredoxin reductase (TrxR1), not from the mitochondrial thioredoxin reductase (TrxR2). Biological roles of TES14 were reported to be involved in regulating TNF-α induced signaling pathways in different manner with Trx1. In depletion experiments, depletion of TRP14 increased TNF-α induced phosphorylation and degradation of IκBα more than the depletion Trx1 did. It also facilitated activation of JNK and p38 MAP kinase induced by TNF-α. Unlike Trx1, TRP14 shows neither interaction nor interference with ASK1. Here, we determined three-dimensional crystal structure of TRP14 by MAD method at 1.8Å. The structure reveals that the conserved cis-Pro (Pro90) and active site-W-C-X-X-C motif, which may be involved in substrate recognition similar to Trx1 , are located at the beginning position of strand β4 and helix α2, respectively. The TRP14 structure also shows that surface of TRP14 in the vicinity of the active site, which is surrounded by an extended flexible loop and an additional short a helix, is different from that of Trx1. In addition, the structure exhibits that TRP14 interact with a distinct target proteins compared with Trx1 and the binding may depend mainly on hydrophobic and charge interactions. Consequently, the structure supports biological data that the TRP14 is involved in regulating TNF-α induced signaling pathways in different manner with Trx1.

• 미생물학회지
• /
• 제52권1호
• /
• pp.1-9
• /
• 2016

치오레독신 환원효소(TrxR)를 encoding하는 Schizosaccharomyces pombe의 유일한 $TrxR^+$ 유전자는 스트레스 반응 전사인자인 Pap1의 매개에 의하여 스트레스 유발 인자들에 의하여 양성적으로 조절됨이 발견되었다. 본 연구에서는, TrxR 과잉 발현 재조합 플라스미드 pHSM10을 사용하여 S. pombe TrxR의 방어적 역할들이 평가되었다. 과산화수소($H_2O_2$)와 superoxide anion을 생성하는 menadione (MD)의 존재 하에서, S. pombe TrxR은 세포성장과 총 글루타치온 (GSH) 수준을 증강시키나, 세포 내 활성산소종(ROS) 수준은 감소시켰다. $H_2O_2$와 MD에 의하여 크게 영향 받지 않는 일산화질소(NO) 수준에는 유의성 없는 효과를 보였다. S. pombe TrxR은 sodium nitroprusside(SNP)에 의하여 생성되는 NO를 소거할 수 있었으나, SNP에 노출된 세포들의 성장, ROS 수준이나 총 글루타치온 수준에는 영향을 보이지 않았다. S. pombe TrxR은 질소 결핍(nitrogen starvation)에 의하여 감소되는 세포 성장 및 총 글루타치온 수준을 증가시키며, 질소 결핍에 의하여 생성되는 ROS와 NO를 소거하였다. 요약하건대, S. pombe TrxR은 산화적, 일산화질소 및 영양 스트레스로부터 효모 세포를 보호하지만, 공통적인 기전에 의하지는 않는다.

• Journal of Microbiology and Biotechnology
• /
• 제28권1호
• /
• pp.145-156
• /
• 2018

Most eukaryotic peroxiredoxins (Prxs) are readily inactivated by a high concentration of hydrogen peroxide ($H_2O_2$) during catalysis owing to their "GGLG" and "YF" motifs. However, such oxidative stress sensitive motifs were not found in the previously identified filamentous fungal Prxs. Additionally, the information on filamentous fungal Prxs is limited and fragmentary. Herein, we cloned and gained insight into Aspergillus nidulans Prx (An.PrxA) in the aspects of protein properties, catalysis characteristics, and especially $H_2O_2$ tolerability. Our results indicated that An.PrxA belongs to the newly defined family of typical 2-Cys Prxs with a marked characteristic that the "resolving" cysteine ($C_R$) is invertedly located preceding the "peroxidatic" cysteine ($C_P$) in amino acid sequences. The inverted arrangement of $C_R$ and $C_P$ can only be found among some yeast, bacterial, and filamentous fungal deduced Prxs. The most surprising characteristic of An.PrxA is its extraordinary ability to resist inactivation by extremely high concentrations of $H_2O_2$, even that approaching 600 mM. By screening the $H_2O_2$-inactivation effects on the components of Prx systems, including Trx, Trx reductase (TrxR), and Prx, we ultimately determined that it is the robust filamentous fungal TrxR rather than Trx and Prx that is responsible for the extreme $H_2O_2$ tolerence of the An.PrxA system. This is the first investigation on the effect of the electron donor partner in the $H_2O_2$ tolerability of the Prx system.

• Biomolecules & Therapeutics
• /
• 제28권5호
• /
• pp.443-455
• /
• 2020

The thioredoxin (Trx) system plays critical roles in regulating intracellular redox levels and defending organisms against oxidative stress. Recent studies indicated that Trx reductase (TrxR) was overexpressed in various types of human cancer cells indicating that the Trx-TrxR system may be a potential target for anti-cancer drug development. This study investigated the synergistic effect of auranofin, a TrxR-specific inhibitor, on sulforaphane-mediated apoptotic cell death using Hep3B cells. The results showed that sulforaphane significantly enhanced auranofin-induced apoptosis by inhibiting TrxR activity and cell proliferation compared to either single treatment. The synergistic effect of sulforaphane and auranofin on apoptosis was evidenced by an increased annexin-V-positive cells and Sub-G1 cells. The induction of apoptosis by the combined treatment caused the loss of mitochondrial membrane potential (ΔΨm) and upregulation of Bax. In addition, the proteolytic activities of caspases (-3, -8, and -9) and the degradation of poly (ADP-ribose) polymerase, a substrate protein of activated caspase-3, were also higher in the combined treatment. Moreover, combined treatment induced excessive generation of reactive oxygen species (ROS). However, treatment with N-acetyl-L-cysteine, a ROS scavenger, reduced combined treatment-induced ROS production and apoptosis. Thereby, these results deduce that ROS played a pivotal role in apoptosis induced by auranofin and sulforaphane. Furthermore, apoptosis induced by auranofin and sulforaphane was significantly increased through inhibition of the phosphoinositide 3-kinase (PI3K)/Akt pathway. Taken together, the present study demonstrated that down-regulation of TrxR activity contributed to the synergistic effect of auranofin and sulforaphane on apoptosis through ROS production and inhibition of PI3K/Akt signaling pathway.

• 생명과학회지
• /
• 제24권7호
• /
• pp.713-720
• /
• 2014

본 연구에서는 Ardisia arborescens 에탄올 추출물(AAEE)의 항산화능과 항염증 생리활성을 in vitro assay system 및 cell culture model system을 이용하여 분석하였다. 먼저 AAEE의 항산화능을 DPPH radical 소거능으로 분석한 결과 양성 대조군으로 사용한 ascorbic acid와 유사한 정도의 높은 활성을 보여 매우 강한 항산화능을 보유함을 확인하였다. 또한 RAW 264.7 세포주를 이용한 $H_2O_2$ 및 LPS의 유도에 의해 생성된 ROS에 대한 소거능을 분석한 결과에서도 농도의존적인 강한 소거능을 보였다. 뿐만 아니라 대표적인 항산화효소로 천연물에 의한 항산화능 활성에 의해 발현이 유도되는 HO-1, TrxR1 및 그 전사 인자인 Nrf2의 단백질 발현이 AAEE의 처리에 의해 농도의존적으로 증가됨을 보였으며 이러한 HO-1, TrxR1 및 Nrf2의 발현 변화는 상위신호전달계인 MAPKs에 의해 조절될 가능성을 보였다. 한편 AAEE가 LPS에 의해 유도된 NO 생성에 미치는 영향을 분석한 결과 세포독성 없이 농도의존적인 NO 생성 저해능을 보였으며 이는 NO 생성 단백질인 iNOS의 발현 저해에서 기인함을 확인하였다. 이와 같은 AAEE의 NO 생성 억제 효과는 염증 상위신호전달계인 NF-${\kappa}B$ 및 AP-1의 조절을 통해 일어날 가능성을 보였다. 이러한 결과를 통해 AAEE의 높은 항산화능과 항염증 활성을 처음으로 확인하였으며 향후 기능성 소재로서 유용하게 활용될 수 있을 것으로 판단된다.

• Asian Pacific Journal of Cancer Prevention
• /
• 제15권3호
• /
• pp.1125-1131
• /
• 2014

Background: Schistosomiasis is a parasitic disease causing chronic ill health in humans with a serious consequences for socio-economic development in tropical and subtropical regions. There is also evidence linking Schistosoma mansoni to colonic carcinoma occurrence. The aim of this study was to evaluate some inflammatory and oxidative stress biomarkers, as well as L-fucose as linkers between intestinal schistosomiasis and colonic dysplasia development in mice. Materials and Methods: This study was conducted upon 80 mice that were divided the control group (10 non infected mice) and infected group which was subdivided into 7 sub-groups (10 mice each) according to the time of sacrifaction in the post infection (p.i.) period, 10 mice being sacrificed every two weeks from 6 weeks p.i. to 18 weeks p.i. Tumor necrosis factor alpha (TNF-${\alpha}$), inducible nitric oxide synthase (iNOS), and pentraxin 3 (PTX3) levels were estimated by immunoassay. The L-fucose level, and thioredoxin reductase (TrxR) and lactate dehydrogenase (LDH) activities were also evaluated in colonic tissue. Results: The current study revealed statistically significant elevation in the studied biochemical markers especially at 16 and 18 weeks p.i. The results were confirmed by histopathological examination that revealed atypical architectural and cytological changes in the form of epithelial surface serration and nuclear hyper-chromatizia at 14, 16 and 18 weeks p.i. Conclusions: inflammation, oxidative stress and L-fucose together may form an important link between Schistosomal mansoni infection and colonic dysplasia and they can be new tools for prediction of colonic dysplasia development in experimental schistosomiasis.