Regulatory B cells in skin and connective tissue diseases

金沢大学医薬保健研究域医学系While B cells are generally considered to be positive regulators of humoral immune responses due to their ability to differentiate into plasmablasts/plasma cells and produce antibodies, B cells also modulate immune responses through antigen presentation and cytokine secretion. Moreover, " regulatory B cells" that suppress immune responses have been recognized as an important new component of the immune system. In mice, the function of regulatory B cells is almost exclusively dependent on IL-10. The cell-surface phenotype of murine IL-10-producing regulatory B cells is reported to be CD1dhiCD5+ or CD1dhiCD21hiCD23+IgMhi, and thus their phenotype overlaps with that of CD5+ B-1a cells, CD1dhiCD21hiCD23loIgMhi marginal zone (MZ) B cells, and CD1dhiCD21hiCD23hiIgMhi T2-MZ precursor B cells. Contrary to earlier work that suggested a minor role for B cells in contact hypersensitivity, regulatory B cells are now known to have a critical inhibitory functions in this type of immune response. Furthermore, studies using murine disease models have demonstrated that regulatory B cells play a significant role in autoimmune connective tissue diseases such as rheumatoid arthritis and systemic lupus erythematosus, as well as organ-specific autoimmune diseases including experimental autoimmune encephalomyelitis and inflammatory bowel disease. In comparison to mouse regulatory B cells, little is known regarding their human counterparts. One recent study demonstrates that human CD19+CD24hiCD38hi B cells possess regulatory capacity. Clarifying the molecular mechanisms by which regulatory B cells suppress immune responses will be of great benefit in the development of new B cell-targeted therapeutic strategies. © 2010 Japanese Society for Investigative Dermatology

Immunological Self Recognition and its Disorders

金沢大学医薬保健研究域医学系マウスにおけるIL-10産生制御性B細胞の特異的マーカーとシグナル伝達経路を、DNAチップを用いた網羅的な発現遺伝子解析を用いて同定することを目的に、野生型のC57BL/6マウスから、脾臓B細胞を分離し、LPS+PMA+イオノマイシン刺激によりIL-10産生を誘導した。これらの細胞を蛍光標識されたモノクローナル抗体にて染色し、高速セルソーターをもちいてIL-10産生細胞をソートした。コントロールとして、同様の処理にてIL-10を産生しないB細胞を用いた。このように細胞からRNAを抽出し、マウスの全遺伝子型DNAチップを用いて、コントロール群との比較により網羅的な発現遺伝子解析を行った。このような解析により、PI3K経路が重要であることが示唆されたため、PTENをB細胞特異的にコンディショナルノックアウト(cKO)したPTEN-cKOマウスを作製した。PTEN-cKOマウスでは、これまでに同定されていない制御性B細胞が著増しており、これらの細胞はin vivoにおいても実験性自己免疫性脳脊髄炎や接触過敏反応を抑制することができた。また、線維化疾患における制御性B細胞の役割を検討するために、全身性強皮症のマウスモデルでもあるブレオマイシン誘導肺線維症のモデルを解析した。B細胞を欠損したuMTマウスでは、肺線維症の増悪が認められ、これは制御性B細胞の移入により改善した。また、マウス抗マウスCD20抗体を用いてB細胞除去療法を行うと、抗体投与時期によって、その反応性の違いが認められた。研究課題/領域番号:22021017, 研究期間(年度):2010 – 201

B細胞シグナル伝達を標的とした自己免疫疾患治療法の開発

1.B細胞の活性化を正に制御する因子であるCD19を欠損したマウスにおいて、DNFB塗布による接触過敏反応を検討した。CD19欠損マウスでは、免疫不全傾向を有し腹腔内B-1細胞が著明に減少しているにもかかわらず、野生型マウスに比べて接触過敏反応が亢進、延長していた。FITC塗布においても同様の結果であった。野生型マウスの脾臓からの辺縁帯B細胞を移入することにより、CD19欠損マウスでの接触過敏反応の亢進は抑制され、辺縁帯B細胞に"RegulatoryB細胞"の役割を担う細胞が存在することが示唆された。以上のことから、CD19が接触過敏反応をはじめとするIV型アレルギーの治療のターゲットになりうると考えられた。2.自己免疫水疱症の発症機序におけるB細胞の関与を検討するために、患者血清におけるBAFFおよび各種ケモカインの濃度を測定し、発症および重症化に寄与する因子を解析した。BAFFは水疱性類天疱瘡患者において発症直前および発症早期に上昇しており、発症に関与する可能性が考えられたが、尋常性天疱瘡患者においては上昇は認められなかった。一方、ケモカインでは、MCP-1, MIG, IP-10の有意な上昇が水庖性類天庖瘡患者血清で認められた。尋常性天疱瘡患者では各サイトカインともに有意な上昇は認められなかった。このように水庖症のそれぞれの疾患の間で発症機序の相違が考えられた。3.全身性エリテマトーデスのモデルであるNZB/NZW F1マウスにおいてもCD19の病態への関与を検討した。CD19を欠損したNZB/NZW F1マウスでは、Regulatory B細胞は欠損しており、これを補充することにより、症状および生存期間の有意な改善が認められ、全身性自己免疫疾患に置いても有望な治療法となりうる可能性が示された。4.BAFFを介したB細胞の自己免疫疾患における線維化機序への関与を検討するために、TSKマウスにおいて抗BAFF抗体投与による症状の改善について検討した。抗BAFF抗体によりマウス皮膚の線維化は有意に抑制された。We assessed the role of the B cell-specific surface molecule CD19 on the development of CHS through examining CD19-deficient mice. CD19 is a member of the Ig superfamily expressed on B cells and follicular dendritic cells, and serves as a positive B-cell response regulator which defines signaling thresholds critical for B cell responses. Contact hypersensitivity (CHS) is a cutaneous immune reaction mediated mainly by Ag-specific effector T cells, and regarded as a model for Th1/Tc1-mediated inflammation, while recent reports have suggested pivotal roles of B cells in CHS. Although CD19-deficient mice are hyposensitive to a variety of transmembrane signals, CD19 loss resulted in increased and prolonged reaction of CHS, suggesting an inhibitory role of CD19 expression in the etiology of CHS. Adoptive transfer experiments revealed that CD19 expression in B cells is recipient mice was required for optimal suppression of CHS response, indicating its role in elicitation phase. Furthermore, spleen B-2 cells, especially marginal zone B cells, from wild type mice were able to normalize exaggerated CHS reactions in CD19-deficient mice. Thus, CD19 expression in B cells is critical for termination of CHS responses, possibly through the function of "regulatory B cells". This B cell subset was also capable for improving murine lupus manifestations.We also assessed serum BAFF and chemokine levels in patieits with autoimmune bullous diseases, and examined BAFF roles in TSK mice, an animal model of systemic sclerosis.研究課題/領域番号:18591239, 研究期間(年度):2006-2007出典：「B細胞シグナル伝達を標的とした自己免疫疾患治療法の開発」研究成果報告書　課題番号18591239 (KAKEN：科学研究費助成事業データベース（国立情報学研究所）)　　　本文データは著者版報告書より作

Eisenhart Lift of 22--Dimensional Mechanics

The Eisenhart lift is a variant of geometrization of classical mechanics with $d$ degrees of freedom in which the equations of motion are embedded into the geodesic equations of a Brinkmann-type metric defined on $(d+2)$-dimensional spacetime of Lorentzian signature. In this work, the Eisenhart lift of $2$-dimensional mechanics on curved background is studied. The corresponding $4$-dimensional metric is governed by two scalar functions which are just the conformal factor and the potential of the original dynamical system. We derive a conformal symmetry and a corresponding quadratic integral, associated with the Eisenhart lift. The energy--momentum tensor is constructed which, along with the metric, provides a solution to the Einstein equations. Uplifts of $2$-dimensional superintegrable models are discussed with a particular emphasis on the issue of hidden symmetries. It is shown that for the $2$-dimensional Darboux--Koenigs metrics, only type I can result in Eisenhart lifts which satisfy the weak energy condition. However, some physically viable metrics with hidden symmetries are presented.Comment: 20 page

A case of biventricular pacing with a spike on T-wave caused by the algorithm maintaining biventricular pacing rate

AbstractCardiac-resynchronization therapy (CRT) improves the cardiac function of patients with left ventricular (LV) dyssynchrony. Maintenance of the biventricular pacing rate is very important in managing the hemodynamics in patients implanted with CRT devices. A low biventricular pacing rate, for example, in cases with atrial fibrillation or rapid intrinsic atrioventricular (AV) conduction, decreases the benefits of CRT. The LUMAX HF-T 540 device series (BIOTRONIK, Berlin, Germany) has a LV-triggered pace algorithm, which allows biventicular pacing rates to be maintained even during rapid intrinsic rhythms caused by shortened AV conduction and/or premature ventricular contraction (PVC) occurring in the right ventricle. We encountered a case of CRT device implantation with a defibrillator wherein this triggered pace algorithm caused a spike on T-wave due to T-wave oversensing. By remote monitoring, we were also able to determine that the T-wave oversensing was due to a PVC. The LUMAX 540 series allows for changes in the sensing threshold and filter settings of the device, which facilitated the elimination of T-wave oversensing in this case

Connective Tissue Growth Factor Gene Expression in Tissue Sections From Localized Scleroderma, Keloid, and Other Fibrotic Skin Disorders

Connective tissue growth factor (CTGF) is a novel peptide that exhibits platelet-derived growth factor-like activities and is produced by skin fibroblasts after activation with transforming growth factor-β. Coordinate expression of transforming growth factor-β followed by CTGF during wound repair suggests a cascade process for control of tissue regeneration. We recently reported a significant correlation between CTGF mRNA expression and histologic sclerosis in systemic sclerosis. To confirm the relation between CTGF and skin fibrosis, we investigated CTGF gene expression in tissue sections from patients with localized scleroderma, keloid, and other sclerotic skin disorders using nonradioactive in situ hybridization. In localized scleroderma, the fibroblasts with positive signals for CTGF mRNA were scattered throughout the sclerotic lesions with no preferential distribution around the inflammatory cells or perivascular regions, whereas the adjacent nonaffected dermis was negative for CTGF mRNA. In keloid tissue, the fibroblasts positive for CTGF mRNA were diffusely distributed, especially in the peripheral expanding lesions. In scar tissue, however, the fibroblasts in the fibrotic lesions showed partially positive signals for CTGF mRNA. In eosinophilic fasciitis, nodular fasciitis, and Dupuytren's contracture, CTGF mRNA was also expressed partially in the fibroblasts of the fibrotic lesions. Our findings reinforce a correlation between CTGF gene expression and skin sclerosis and support the hypothesis that transforming growth factor-β plays an important role in the pathogenesis of fibrosis, as it is the only inducer for CTGF identified to date

Decreased levels of regulatory B cells in patients with systemic sclerosis: Association with autoantibody production and disease activity

Objective. B cell abnormalities characterized by autoantibody production and polyclonal B cell activation play an important role in the pathogenesis of SSc. IL-10 producing regulatory B (Breg) cells also play an important role in the negative immune response. We identified a human Breg cell subset that was predominantly found within the CD24hiCD27+ B cell subpopulation. However, the role of Breg cells in SSc remains unknown. The aim of this study was to investigate the clinical association of Breg cells in SSc patients. Methods. Blood IL-10 producing Breg cell levels were determined by FACS in 35 SSc patients and 30 healthy subjects. In a follow-up study, we analysed six individual dcSSc patients before and after treatment. Results. The frequency of blood Breg cells was significantly lower in SSc patients than in healthy controls (P<0.0001). Similarly, the frequency of CD24hiCD27+ B cells was significantly lower in SSc patients than in healthy controls (P<0.0001). SSc patients with decreased Breg cell levels often had interstitial lung disease (P<0.05). Furthermore, Breg cell levels correlated negatively with the titre of anti-topo I antibody (Ab) and anticentromere Ab in SSc patients. For a follow-up study, Breg cell levels in dcSSc patients after treatment were found to be significantly increased compared with those before treatment (P<0.05), accompanied by decreased disease activity. Thus, Breg cell levels were inversely correlated with disease activity of SSc. Conclusion. These results suggest that decreased Breg cell levels may contribute to the development of SSc. © The Author 2015.Embargo Period 12 month