• IMMUNE NETWORK
• /
• 제13권4호
• /
• pp.116-122
• /
• 2013

This study was conducted to determine whether CD4 T cell responses to citrullinated fibrinogen occur in patients with rheumatoid arthritis (RA), especially in HLA-DR4-positive subjects. Whole peripheral blood mononuclear cells (PBMCs) of RA patients and control subjects were stimulated with citrullinated fibrinogen peptides, and T-cell production of proliferation and proinflammatory cytokines, such as interferon-${\gamma}$(IFN-${\gamma}$) and interleukin-17A (IL-17A), were measured. In addition, CD4 T cells from RA patients were stimulated with the citrullinated fibrinogen peptide, $Fib-{\alpha}$ R84Cit, identified as a DRB1*0401-restricted T cell epitope in HLA-DR4 transgenic mice, and the degree of T cell activation was examined similarly. No proliferative responses to the citrullinated fibrinogen peptides were observed in whole PBMCs or CD4 T cells from RA patients. Furthermore, no increased production of IFN-${\gamma}$ or IL-17A was found in whole PBMCs or CD4 T cells stimulated with the citrullinated fibrinogen peptides, although these cells responded to recall antigen, a mixture of tetanus toxoid, purified protein derivative (PPD) from Mycobacterium tuberculosis, and Candida albicans. The results of this study indicate that anti-citrulline immunity in RA patients may be mediated by fibrinogen because there is no evidence of CD4 T cell-mediated immune responses to citrullinated fibrinogen peptides.

• 한국산학기술학회논문지
• /
• 제14권5호
• /
• pp.2393-2399
• /
• 2013

본 논문에서는 특이값 분해(SVD: singular value decomposition)에 의한 기저 스펙트럼의 합성을 통해 혈소판 라만 스펙트럼에서 알츠하이머병(AD: Alzheimer's disease)을 검출하는 방법을 제안하였다. AD가 유도된 형질 전환 실험용 쥐의 혈소판에서 측정한 라만 스펙트럼은 가산 잡음과 배경 잡음의 제거와 정규화로 구성된 전처리 과정을 수행한다. 각 데이터 행렬의 열벡터는 AD와 정상(NR: normal)의 라만 스펙트럼으로 구성한다. 이 데이터 행렬을 SVD로 분해한 다음 각 행렬의 열벡터 12개를 AD와 NR의 기저 스펙트럼으로 결정한다. 분류 과정은 각 클래스의 기저 스펙트럼을 선형 합성한 스펙트럼과 분류 스펙트럼의 평균제곱근오차(root mean square error)가 최소인 클래스를 선택하는 것으로 완료된다. 278개의 혈소판 라만 스펙트럼을 사용한 실험에 따르면 제안한 방법의 평균 분류율은 약 97.6%로 주성분 분석(principle components analysis)으로 추출한 특징에 MLP(multi-layer perceptron)를 이용한 경우보다 약 6.1% 정도의 우수한 성능을 보였다. 이 결과에서 SVD에 의한 기저 스펙트럼이 혈소판 라만 스펙트럼에서 AD의 검출에 적합하게 사용될 수 있음을 확인하였다.

• Maxillofacial Plastic and Reconstructive Surgery
• /
• 제28권2호
• /
• pp.111-117
• /
• 2006

An area of current research is investigating the app1ication of human mesenchymal stem cells or hMSCs as a cell-based regenerative therapy. In order to achieve effective bone regeneration, appropriate matrices functioning as cell-carriers must be identified and optimized in terms of function, efficacy and biocompatibility. Two methods of approaching optimization of matrices are to facilitate adhesion of the donor hMSCs and furthermore to facilitate recruitment of host progenitor cells to osteoblastic differentiation. Pleiotrophin is an extracellular matrix protein that was first identified in developing rat brains and believed to be associated with developing neuronal pathways. A recent publication by Imai and colleagues demonstrated that transgenic mice with upregulated pleiotrophin expression developed a greater volume of cortical as well as cancellous bone. The proposed mechanism of action of pleiotrophin is demonstrated here. Through either environmental stresses and/or intracellular regulation, there is an increase in pleiotrophin production. The pleiotrophin is released extracellularly into areas requiring bone deposition. A receptor-mediated process recruits host osteoprogenitor cells into these areas. Therefore, the aim of our study was to investigate the osteoconductive properties of pleiotrophin. We wanted to determine if pleiotrophin coating facilitates cellular adhesion and furthermore if this has any effect on hMSCs derived bone formation in an animal model. The results showed a dose dependent response of cellular adhesion in fibronectin samples, and cellular adhesion was facilitated with increasing pleiotrophin concentrations. Histologic findings taken after 5 weeks implantation in SCID mouse showed no presence of bone formation with only a dense fibrous connective tissue. Possible explanations for the results of the osteogenesis assay include inappropriate cell loading.

• 전자공학회논문지CI
• /
• 제49권1호
• /
• pp.16-22
• /
• 2012

본 논문에서는 알츠하이머병이 유도된 형질전환 마우스로부터 획득한 혈소판 라만 스펙트럼의 분석을 위해 가우시안 모델을 이용한 커브 피팅으로 기준선을 추정하고 보정하는 방법을 제안하였다. 측정된 라만 스펙트럼은 의미 있는 정보와 불필요한 노이즈 성분인 기준선과 가산 노이즈를 포함하고 있다. 스펙트럼의 효율적인 분석을 위해 노이즈를 포함하고 있는 스펙트럼을 몇 개의 피크를 포함하는 영역으로 분할하고 각 로컬 영역의 스펙트럼을 가우시안 모델을 이용한 커브 피팅으로 모델링한다. 가산 노이즈는 원 스펙트럼을 이 델로 대체하는 과정에서 명백하게 제거된다. 피팅된 모델의 로컬 최저점을 linear, piecewise cubic Hermite, cubic spline 알고리즘으로 보간하고 기준선을 보정한다. 기준선을 보정한 피팅 모델은 PCA(principal component analysis) 방법을 이용하여 특징을 추출하고 SVM(support vector machine)과 MAP(maximum $a$ posteriori probability) 분류 방법으로 성능 비교 실험을 하였다. 실험 결과에 따르면 linear 보간법이 모든 주성분 수에 대한 분류율의 평균에서 우세하였고 특히 piecewise cubic Hermite 보간법은 주성분의 수가 5개인 경우에서 SVM 분류율이 약 97.3%로 가장 좋은 성능을 보였다. 또한 이전의 연구 결과와 비교를 통해 제안한 기준선 보정 방법이 혈소판 라만 스펙트럼의 분석에 효과적으로 적용될 수 있음을 확인하였다.

• 한국수정란이식학회:학술대회논문집
• /
• 한국수정란이식학회 2002년도 국제심포지엄
• /
• pp.97-97
• /
• 2002

Human eryhropoietin (EPO) is acidic glycoprotein hormone that plays key role in hematopoiesis by facilitating differentiation of erythrocyte and formation of hemoglobin (Hb) and is used for the treatment of anemia. Human EPO is consist of 166 amino acids which is modified by three N-glycosylations (24, 38, 83) and single O-glycosylation (126). N-glycosylation is reported to be related to the cellular secretion and activity of EPO. In this study, we examined effects of mutagenesis in glycosylation site of recombinat hEPO for the cellular secretion during production from cultured CHO cell. We produced rhEpo which was cloned by PCR from human liver cDNA (TaKaRa) in cultured CHO cell. Using supernatant of the culture, ELISA assay and western analysis were performed. To estimate biological activity, 20IU of rhuEpo was subcutaneously injected into four ICR mice. After 8 days, HCT level was increased average 13 per cent, RBC was increased ca. 2${\times}$10$\^$6//${\mu}\ell$. In disease model Rat (anemia c-kit, WSRC-WS/WS), HCT was increased ca. 12%, RBC was increased ca. 1.6${\times}$10$\^$6//${\mu}\ell$. These results suggests that rhEpo we produced has biological activity. To remove glycosylation site by substituting 24, 38, 83, and 126th asparagine (or serine) with glutamic acid, overlapping -extension site-directed mutagenesis was performed. To add novel glycosylation sites, 69, 105th leucine was mutated to asparagine. Mutant EPO construct was transfected into CHO cell. Supernatant of the cell culture was analyzed using ELISA assay with monoclonal anti-EPO antibody (Medac, Germany). Since, several reports for mutagenesis of glycosylation sites showed case-by-case results, we examined both transient expression and stable expression. Addition of novel glycosylation sites resulted no secretion while deletion mutants had little effect except some double deletion mutants (24/83 and 38/83) and triple mutant. We suggest that not single but combination of glycosyl group affect secretion of EPO.

• Journal of Genetic Medicine
• /
• 제4권1호
• /
• pp.22-37
• /
• 2007

The autosomal dominant spinocerebellar ataxias (SCAs) are a group of neurodegenerative diseases, clinically and genetically heterogeneous, characterized by degeneration of spinocerebellar pathways with variable involvement of other neural systems. At present, 27 distinct genetic forms of SCAs are known: SCA1-8, SCA10-21, SCA23, SCA25-28, DRPLA (dentatorubral-pallidoluysian atrophy), and 16q-liked ADCA (autosomal dominant cerebellar ataxia). Epidemiological data about the prevalence of SCAs are restricted to a few studies of isolated geographical regions, and most do not reflect the real occurrence of the disease. In general a prevalence of about 0.3-2 cases per 100,000 people is assumed. As SCA are highly heterogeneous, the prevalence of specific subtypes varies between different ethnic and continental populations. Most recent data suggest that SCA3 is the commonest subtype worldwide; SCA1, SCA2, SCA6, SCA7, and SCA8 have a prevalence of over 2%, and the remaining SCAs are thought to be rare (prevalence <1%). In this review, we highlight and discuss the SCA7. The hallmark of SCA7 is the association of hereditary ataxia and visual loss caused by pigmentary macular degeneration. Visual failure is progressive, bilateral and symmetrical, and leads irreversibly to blindness. This association represents a distinct disease entity classified as autosomal dominant cerebellar ataxia (ADCA) type II by Harding. The disease affectsprimarily the cerebellum and the retina by the moderate to severe neuronal loss and gliosis, but also many other central nervous system structures as the disease progresses. SCA7 is caused by expansion of an unstable trinucleotide CAG repeat in the ATXN7 gene encoding a polyglutamine (polyQ) tract in the corresponding protein, ataxin-7. Normal ATXN7 alleles contain 4-35 CAG repeats, whereas pathological alleles contain from 36->450 CAG repeats. Immunoblott analysis demonstrated that ataxin-7 is widely expressed but that expression levels vary among tissues. Instability of expanded repeats is more pronounced in SCA7 than in other SCA subtypes and can cause substantial lowering of age at onset in successive generations termed ‘anticipation’ so that children may become diseased even before their parents develop symptoms. The strong anticipation in SCA7 and the rarity of contractions should have led to its extinction within a few generations. There is no specific drug therapy for this neurodegenerative disorder. Currently, therapy remains purely symptomatic. Cellular models and SCA7 transgenic mice have been generated which constitute valuable resources for studying the disease mechanism. Understanding the pathogenetic mechanisms of neurodegeneration in SCAs should lead to the identification of potential therapeutic targets and ultimately facilitate drug discovery. Here we summarize the clinical, pathological, and genetic aspects of SCA7, and review the current understanding of the pathogenesis of this disorder. Further, we also review the potential therapeutic strategies that are currently being explored in polyglutamine diseases.

• IMMUNE NETWORK
• /
• 제22권3호
• /
• pp.22.1-22.25
• /
• 2022

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndromecoronavirus-2 (SARS-CoV-2), has spread over the world causing a pandemic which is still ongoing since its emergence in late 2019. A great amount of effort has been devoted to understanding the pathogenesis of COVID-19 with the hope of developing better therapeutic strategies. Transcriptome analysis using technologies such as RNA sequencing became a commonly used approach in study of host immune responses to SARS-CoV-2. Although substantial amount of information can be gathered from transcriptome analysis, different analysis tools used in these studies may lead to conclusions that differ dramatically from each other. Here, we re-analyzed four RNA-sequencing datasets of COVID-19 samples including human bronchoalveolar lavage fluid, nasopharyngeal swabs, lung biopsy and hACE2 transgenic mice using the same standardized method. The results showed that common features of COVID-19 include upregulation of chemokines including CCL2, CXCL1, and CXCL10, inflammatory cytokine IL-1β and alarmin S100A8/S100A9, which are associated with dysregulated innate immunity marked by abundant neutrophil and mast cell accumulation. Downregulation of chemokine receptor genes that are associated with impaired adaptive immunity such as lymphopenia is another common feather of COVID-19 observed. In addition, a few interferon-stimulated genes but no type I IFN genes were identified to be enriched in COVID-19 samples compared to their respective control in these datasets. These features are in line with results from single-cell RNA sequencing studies in the field. Therefore, our re-analysis of the RNA-seq datasets revealed common features of dysregulated immune responses to SARS-CoV-2 and shed light to the pathogenesis of COVID-19.

• Tuberculosis and Respiratory Diseases
• /
• 제79권3호
• /
• pp.143-152
• /
• 2016

Background: Idiopathic pulmonary fibrosis (IPF) is a progressive and lethal lung disease characterized by the accumulation of excessive fibroblasts and myofibroblasts in the extracellular matrix. The transforming growth factor ${\beta}1$ (TGF-${\beta}1$)-induced epithelial-to-mesenchymal transition (EMT) is thought to be a possible source of fibroblasts/myofibroblasts in IPF lungs. We have previously reported that apolipoprotein A1 (ApoA1) has anti-fibrotic activity in experimental lung fibrosis. In this study, we determine whether ApoA1 modulates TGF-${\beta}1$-induced EMT in experimental lung fibrosis and clarify its mechanism of action. Methods: The A549 alveolar epithelial cell line was treated with TGF-${\beta}1$ with or without ApoA1. Morphological changes and expression of EMT-related markers, including E-cadherin, N-cadherin, and ${\alpha}$-smooth muscle actin were evaluated. Expressions of Smad and non-Smad mediators and TGF-${\beta}1$ receptor type 1 ($T{\beta}RI$) and type 2 ($T{\beta}RII$) were measured. The silica-induced lung fibrosis model was established using ApoA1 overexpressing transgenic mice. Results: TGF-${\beta}1$-treated A549 cells were changed to the mesenchymal morphology with less E-cadherin and more N-cadherin expression. The addition of ApoA1 inhibited the TGF-${\beta}1$-induced change of the EMT phenotype. ApoA1 inhibited the TGF-${\beta}1$-induced increase in the phosphorylation of Smad2 and 3 as well as that of ERK and p38 mitogen-activated protein kinase mediators. In addition, ApoA1 reduced the TGF-${\beta}1$-induced increase in $T{\beta}RI$ and $T{\beta}RII$ expression. In a mouse model of silica-induced lung fibrosis, ApoA1 overexpression reduced the silica-mediated effects, which were increased N-cadherin and decreased E-cadherin expression in the alveolar epithelium. Conclusion: Our data demonstrate that ApoA1 inhibits TGF-${\beta}1$-induced EMT in experimental lung fibrosis.

• 한국발생생물학회지:발생과생식
• /
• 제6권1호
• /
• pp.55-66
• /
• 2002

배아줄기세포(embryonic stem cell, ESC)는 미분화상태로 지속적인 계대가 가능하며, 정상 핵형과 전 분화능(pluripotency)을 가져 생체내-외에서 분화 유도시 삼배엽성의 모든 세포로 분화 가능하다. ESC를 feeder 세포 없이 부유배양하면 배아체(embryoid body, EB)를 형성하고, 초기 배아 발생과 유사한 분화 양상을 갖는다. ESC의 분화 유도가 초기배아 발생처럼 생식호르몬(GTH: FSH, LH; steroids)의 영향을 받는지는 불명하다. 본 연구는 ESC가 분화과정중 생식호르몬처리에 의해 그들 수용체가 발현되는가를 알아보고자 하였다. 순계혈통 생쥐인 C57BL/6J에서 과배란 유도후 포배를 수획하고, 유사분열적으로 불활성화된 feeder 세포와 공배양하여, 계대배양 하는 중 배아줄기세포주(JHYl)를 확립하였다. JHY1의 alkaline phosphatase 활성과 SSEA-1, 3, 4 발현을 통해 ESC임을 확인하였다. Feeder 세포 없이 ESC를 계대배양 후 호르몬처리(FSH LH E$_2$, P$_4$, T)하에서 5일 동안 부유배양하여 배아체를 형성시키고, 이후 7일 동안 부착배양하여 분화를 유도하였다. GTH와 스테로이드의 수용체 발현 실험에서 ESC에 E$_2$ 처리에 의한 LHR의 발현 증가를 제외한 나머지 호르몬 처리군에서 ESC보다 낮은 생식호르몬의 수용체 발현이 관찰되었다. 생식호르몬을 농도별 수용체 발현 정도는 증감되지 않았다. 미분화 ESC 표지유전자인 Oct-4는 호르몬 처리군에서도 발현되었다. 각 배엽의 표지유전자들(영양세포, handl; 외배엽성, keratin와fgf-5; 중배엽성, enolase와 $\alpha$ -globin; 내배엽성, gata-4와 $\alpha$ -fetoprotein) 등의 발현 양상을 조사한 결과 호르몬 처리후 내배엽성 표지유전자외에는 발현 증가가 관찰되지 않았다. 즉 생식호르몬에 의해 gata-4, $\alpha$-fetoprotein의 발현이 증가되는 것으로 보아 내배엽성 계열로의 분화 유도가 이루어진 것으로 사료된다.