• 한국가금학회지
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• 제45권3호
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• pp.209-217
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• 2018

The innate immune recognition is based on the detection of microbial products. Toll-like receptors (TLRs) located on the cell surface and the endosome senses microbial components and nucleic acids, respectively. Chicken TLRs mediate immune responses by sensing ligands from pathogens, have been studied as immune adjuvants to increase the efficacy of vaccines. Single nucleotide polymorphisms (SNPs) of TLR3 and TLR4 genes in chicken were associated with resistance and susceptibility to viral infection. In this study, SNPs of chTLR3 and chTLR4 genes were retrieved from public database and annotated with chicken reference genome. Three-dimensional models of the chTLR3 and chTLR4 proteins were built using a Swiss modeler. We identified 35 and 13 nsSNPs in chTLR3 and chTLR4 genes respectively. Sorting Intolerant from Tolerant (SIFT) and Polymorphism Phenotyping v2 (Polyphen-2) analyses, suggested that, out of 35 and 13 nsSNPs, 4 and 2 SNPs were identified to be deleterious in chTLR3 and chTLR4 gene respectively. In chTLR3, 1 deleterious SNP was located in ectodomain and 3 were located in the Toll / IL-1 receptor (TIR) domain. Further structural model of chTLR3-TIR domain suggested that 1 deleterious SNP be present in the B-B loop region, which is important for TIR-TIR domain interactions in the downstream signaling. In chTLR4, the deleterious SNPs were located both in the ectodomain and TIR domain. SNPs predicted for chTLR3 and chTLR4 in this study, might be related to resistance or susceptible to viral infection in chickens. Results from this study will be useful to develop the effective measures in chicken against infectious diseases.

• 한국식품과학회지
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• 제39권2호
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• pp.175-180
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• 2007

TLRs는 병원균이 숙주의 몸 속에 들어 왔을 때, 병원균들이 가지고 있는 독특한 구조를 인식하여 선천성 면역반응과 뒤이어 후천성 면역반응을 유도하는 중요한 역할을 한다. 우리는 이번 실험을 통하여 curcumin이 선행연구에서 밝혀낸 TLR4 뿐만 아니라 TLR2와 TLR6 그리고 TLR3를 또한 분자학적인 타깃으로 할 수 있다는 것을 알아내었다. Curcumin이 MALP-2(TLR2,6 agonist)에 의해서 유도된 IRAK-1 degradation을 억제시켰다. 이러한 결과는 curcumin의 분자학적인 타깃이 IRAK-1위에 놓여 있으며, TLR2와 TLR6가 될 것이라는 가능성을 제시해 준다고 할 수 있다. 또한 curcumin은 viral 자극제인 poly[I:C](TLR3 agonist)에 의해서 유도된 IRF3나 $NF-{\kappa}B$ 활성화를 억제하였지만, TRIF에 의해서 유도된 IRF3 활성화는 억제시키지를 못하였다. 이러한 결과 또한 TLR3 자체가 curcumin의 분자학적인 타깃이라는 가능성을 제시해 준다고 할 수 있겠다. 이러한 결과를 종합해 볼때, curcumin의 분자학적인 타깃이 $IKK{\beta}$ 이외에 모든 TLRs가 될 수 있다는 가능성을 제시해 준다고 할 수 있겠다. 이러한 결과는 curcumin이 그람음성균 뿐만이 아니라 바이러스나 박테리아 등 여러 병원균들로부터 유도되는 염증반응이나 만성적인 질병들을 조절할 수 있다는 것을 보여주는 결과라 할 수 있겠다.

• Journal of Veterinary Science
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• 제23권2호
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• pp.27.1-27.16
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• 2022

Background: The role of Toll-like receptors (TLRs) in a feline infectious peritonitis virus (FIPV) infection is not completely understood. Objectives: This study examined the expression of TLR3, TLR7, TLR9, tumor necrosis factor-alpha (TNF-α), interferon (IFN)-β, and interleukin (IL)-10 upon an FIPV infection in Crandell-Reese feline kidney (CRFK) cells and feline monocytes. Methods: CRFK cells and monocytes from feline coronavirus (FCoV)-seronegative cats and FCoV-seropositive cats were infected with type II FIPV-79-1146. At four, 12, and 24 hours post-infection (hpi), the expression of TLR3, TLR7, TLR9, TNF-α, IFN-β, and IL-10, and the viral load were measured using reverse transcription quantitative polymerase chain reaction. Viral protein production was confirmed using immunofluorescence. Results: FIPV-infected CRFK showed the upregulation of TLR9, TNF-α, and IFN-β expression between 4 and 24 hpi. Uninfected monocytes from FCoV-seropositive cats showed lower TLR3 and TLR9 expression but higher TLR7 expression compared to uninfected monocytes from FCoV-seronegative cats. FIPV-infected monocytes from FCoV-seropositive cats downregulated TLR7 and TNF-α expression between 4 and 24 hpi, and 4 and 12 hpi, respectively. IFN-β was upregulated early in FIPV-infected monocytes from FCoV-seropositive cats, with a significant difference observed at 12 hpi compared to FCoV-seronegative cats. The viral load in the CRFK and FIPV-infected monocytes in both cohorts of cats was similar over time.ConclusionTLR7 may be the key TLR involved in evading the innate response against inhibiting TNF-α production. Distinct TLR expression profiles between FCoV-seronegative and FCoV-seropositive cats were observed. The associated TLR that plays a role in the induction of IFN-β needs to be explored further.

• IMMUNE NETWORK
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• 제20권3호
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• pp.21.1-21.10
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• 2020

TLRs are pattern recognition receptors (PRRs) whose cytoplasmic signalling domain is similar to that of IL-1. The extracellular domain of TLRs serve as the binding site of pathogen associated molecular patterns. TLRs are found on both plasma and endosomal membranes and they mainly exert their function by activating genes which lead to production of inflammatory factors. The latest TLR to be discovered, TLR10 is a unique TLR which exhibit anti-inflammatory properties. TLR10 is found on the plasma membrane with other TLRs namely TLR1, TLR2, TLR4, TLR5 and TLR6. Studies have revealed that TLR10 is found on the same gene cluster with TLR1 and TLR6 and is also a coreceptor of TLR2. Up to date, TLR10 is the only TLR which exhibit anti-inflammatory property. Previously, TLR10 was thought to be an "orphan receptor" but much recent studies have identified ligands for TLR10. Currently there is no review article on TLR10 that has been published. In this narrative review, we are going to give an account of TLR10, its functions mainly as an anti-inflammatory PRR and its possible applications as a target in therapeutics.

• Clinical and Experimental Reproductive Medicine
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• 제45권4호
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• pp.154-162
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• 2018

Objective: The fallopian tubes play a critical role in the early events of fertilization. The rapid innate immune defense is an important part of the fallopian tubes. Toll-like receptor 3 (TLR3), as a part of the innate immune system, plays an important role in detecting viral infections. In this basic and experimental study, the effect of sex hormones on the function of TLR3 in the OE-E6/E7 cell line was investigated. Methods: The functionality of TLR3 in this cell line was evaluated by cytokine measurements (interleukin [IL]-6 and IL-1b) and the effects of sex hormones on TLR3 were tested by an enzyme-linked immunosorbent assay kit. Additionally, TLR3 small interfering RNA (siRNA) and a TLR3 function-blocking antibody were used to confirm our findings. Results: The production of IL-6 significantly increased in the presence of polyinosinic-polycytidylic acid (poly(I:C)) as the TLR3 ligand. Using a TLR3-siRNA-ransfected OE-E6/E7 cell line and function-blocking antibody confirmed that cytokine production was due to TLR3. In addition, 17-${\beta}$ estradiol and progesterone suppressed the production of IL-6 in the presence and absence of poly(I:C). Conclusion: These results imply that sex hormones exerted a suppressive effect on the function of TLR3 in the fallopian tube cell line when different concentrations of sex hormones were present. The current results also suggest that estrogen receptor beta and nuclear progesterone receptor B are likely to mediate the hormonal regulation of TLR3, as these two receptors are the main estrogen and progesterone receptors in OEE6/E7 cell line.

• BMB Reports
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• 제49권6호
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• pp.305-310
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• 2016

Toll-like receptors (TLRs) play a critical role in the innate immune response against pathogens. Each TLR recognizes specific pathogen-associated molecular patterns, after which they activate the adaptor protein MyD88 or TRIF-assembled signaling complex to produce immune mediators, including inflammatory cytokines and type I IFNs. Although the activation of TLR is important for host defense, its uncontrolled activation can damage the host. During the past decade, numerous studies have demonstrated that GSK3β is a key regulator of inflammatory cytokine production in MyD88-mediated TLR signaling via TLR2 and TLR4. Recently, GSK3β has also been implicated in the TRIF-dependent signaling pathway via TLR3. In this review, we describe current advances on the regulatory role of GSK3β in immune responses associated with various TLRs. A better understanding of the role of GSK3β in TLR signaling might lead to more effective anti-inflammatory interventions.

• Molecules and Cells
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• 제38권1호
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• pp.58-64
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• 2015

Activating transcription factor-3 (ATF3) acts as a negative regulator of cytokine production during Gram-negative bacterial infection. A recent study reported that ATF3 provides protection from Streptococcus pneumoniae infection by activating cytokines. However, the mechanism by which S. pneumoniae induces ATF3 after infection is still unknown. In this study, we show that ATF3 was upregulated via Toll-like receptor (TLR) pathways in response to S. pneumoniae infection in vitro. Induction was mediated by TLR4 and TLR2, which are in the TLR family. The expression of ATF3 was induced by pneumolysin (PLY), a potent pneumococcal virulence factor, via the TLR4 pathway. Furthermore, ATF3 induction is mediated by p38 mitogen-activated protein kinase (MAPK) and c-Jun N-terminal kinase (JNK). Thus, this study reveals a potential role of PLY in modulating ATF3 expression, which is required for the regulation of immune responses against pneumococcal infection in macrophages.

• Clinical and Experimental Pediatrics
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• 제52권6호
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• pp.667-673
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• 2009

목 적 : TLR2는 숙주의 항결핵 방어면역의 중요한 역할을 하는 것으로 알려져 있다. 본 연구는 BCG 접종 후 발생한 화농성 림프절염 환자 단핵구에서 TLR2의 발현과 TLR2 리간드 자극에 의한 $TNF-{\alpha}$와 IL-6의 생성을 조사하여 화농성 림프절염 발병과 TLR2의 연관성을 알아보고자 하였다. 방 법 : BCG 접종 후 발생한 화농성 림프절염 환자 16명과 건강 대조군 10명의 말초 혈액에서 단핵구를 분리하고, TLR2 리간드인 Pam3CSK4로 자극한 후 유세포분석과 역전사중합효소반응을 이용하여 TLR2의 발현을 측정하였고, 자극 후 $TNF-{\alpha}$와 IL-6의 생성을 측정하여 TLR2의 발현 정도를 간접적으로 조사하였다. 결 과 : BCG 접종 후 발생한 화농성 림프절염 환자 단핵구의 TLR2 발현 정도($3.39{\pm}1.2%$)는 대조군($4.64{\pm}2.6%$)에 비하여 유의하게 감소하였고, 단핵구 자극에 의한 $TNF-{\alpha}$와 IL-6의 생성도 대조군($TNF-{\alpha}$, $1,098.5{\pm}94.3pg/mL$; IL-6, $6,696.3{\pm}544.3pg/mL$)에 비하여 환자군($TNF-{\alpha}$, $775.5{\pm}60.8pg/mL$; IL-6, $4,645.8{\pm}583.9pg/mL$)에서 유의하게 감소하였다. 그리고 자극 시간에 따른 TLR2 발현 정도와 $TNF-{\alpha}$와 IL-6의 생성 증가가 유사한 양상을 나타내었다. 결 론 : 본 연구의 결과에서 BCG 접종 후 발생한 화농성 림프절염 환자군 단핵구의 TLR2 발현 감소가 연관되어 있고, M. bovis BCG의 리간드 인식에 TLR2가 관여함을 추정할 수 있다.

• 한국가금학회지
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• 제50권4호
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• pp.283-291
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• 2023

지방산 결합 단백질(FABP)은 LCFA 수송, 지질 합성, 저장을 용이하게 하고, 염증을 포함한 다양한 경로에 영향을 미치는 신호 분자로 작용한다. 특히 FABP4는 혈관 및 심장관련 질환과 관련이 있으며, 대식세포 매개 염증 반응에서 역할을 한다. 이전의 연구들은 FABP4를 지방 생성을 위한 대표적인 바이오 마커일 뿐만 아니라, 면역 반응과도 상관관계가 있는 것으로 확인하였다. 본 연구는 톨-유사 수용체 3(TLR3) 활성화에 의한 닭 FABP4(chFABP4) 유전자의조절을 조사하고 chFABP4 전사 조절에 관여하는 신호 경로를 결정하는 것을 목표로 한다. 우리는 TLR3 자극 DF-1 세포에서 chFABP4의 전사 조절을 분석하였다. 결과는 TLR3 리간드인 폴리이노신-폴리시티딜산(PIC)으로 자극 시 chFABP4가 상향 조절되었음을 보여주었다. 특히 chFABP4 전사는 NF-κB 신호 경로에서 독립적으로 조절되었다. p38 억제에서 상향 조절되어 p38 신호 경로가 TLR3 활성화 DF-1 세포 내에서 chFABP4 전사를 억제할 수 있음을 보여주었다. 이와는 대조적으로, JNK 신호 경로 억제에서는 chFABP4 발현이 하향 조절되었으며, 이는 대식세포의 연구 결과와 일치하며, TLR3 활성화에 반응하여 DF-1 세포에서 chFABP4 전사를 위한 JNK 신호 전달 경로의 긍정적인 조절을 시사한다. MEK 경로 억제는 NF-κB 신호 전달과 유사한 조절을 초래하였다. 이러한 결과는 각 MAPK가 TLR3 활성화에 반응하여 DF-1 세포에서 chFABP4의 전사 조절에 차별적으로 기여함을 시사한다.

• IMMUNE NETWORK
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• 제13권5호
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• pp.194-198
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• 2013

Recent papers have shown that the initial event in the pathogenesis of autoimmune type 1 diabetes (T1D) comprises sensing of molecular patterns released from apoptotic ${\beta}$-cells by innate immune receptors such as toll-like receptor (TLR). We have reported that apoptotic ${\beta}$-cells undergoing secondary necrosis called 'late apoptotic' ${\beta}$-cells stimulate dendritic cells (DCs) and induce diabetogenic T cell priming through TLR2. The role of other innate immune receptors such as TLR7 or TLR9 in the initiation of T1D has also been suggested. We hypothesized that TLR2 blockade could inhibit T1D at the initial step of T1D. Indeed, when a TLR2 agonist, $Pam3CSK_4$ was administered chronically, the development of T1D in nonobese diabetic (NOD) mice was inhibited. Diabetogenic T cell priming by DCs was attenuated by chronic treatment with $Pam3CSK_4$, indicating DC tolerance. For the treatment of established T1D, immune tolerance alone is not enough because ${\beta}$-cell mass is critically reduced. We employed TLR2 tolerance in conjunction with islet transplantation, which led to reversal of newly established T1D. Dipeptidyl peptidase 4 (DPP4) inhibitors are a new class of anti-diabetic agents that have beneficial effects on ${\beta}$-cells. We investigated whether a combination of DPP4 inhibition and TLR2 tolerization could reverse newly established T1D without islet transplantation. We could achieve normoglycemia by TLR2 tolerization in combination with DPP4 inhibition but not by TLR2 tolerization or DPP4 inhibition alone. ${\beta}$-cell mass was significantly increased by combined treatment with TLR2 tolerization and DPP4 inhibition. These results suggest the possibility that a novel strategy of TLR tolerization will be available for the inhibition or treatment of established T1D when combined with measures increasing critically reduced ${\beta}$-cell mass of T1D patients such as DPP4 inhibition or stem cell technology.