In vivo notch reactivation in differentiating cochlear hair cells induces sox2 and prox1 expression but does not disrupt hair cell maturation

COVER PHOTOGRAPH: Lineage tracing of Prox1 expressing inner ear cochlear cells in Prox1CreEGFP/+; Rosa26‐EYFPloxp/+ mice at P23. All cochlear hair cells are labeled with calbindin in red. EYFP in green historically records the cochlear cells experiencing Prox1 expression during the development, which include hair cells and supporting cells (both inside and outside the organ of Corti). From Liu et al., Developmental Dynamics 241:684–696, 2012.     

In vivo Notch reactivation in differentiating cochlear hair cells induces Sox2 and Prox1 expression but does not disrupt hair cell maturation

Background: Notch signaling is active in mouse cochlear prosensory progenitors but declines in differentiating sensory hair cells (HCs). Overactivation of the Notch1 intracellular domain (NICD) in progenitors blocks HC fate commitment and/or differentiation. However, it is not known whether reactivation of NICD in differentiating HCs also interrupts their developmental program and reactivates its downstream targets. Results: By analyzing Atoh1^CreER+; Rosa26‐NICD^loxp/+ or Atoh1^CreER+; Rosa26‐NICD^loxp/+; RBP‐J^loxp/loxp mice, we demonstrated that ectopic NICD in differentiating HCs caused reactivation of Sox2 and Prox1 in an RBP‐J‐dependent manner. Interestingly, Prox1 reactivation was exclusive to outer HCs (OHCs). In addition, lineage tracing analysis of Prox1^CreER/+; Rosa26‐EYFP^loxp/+ and Prox1^CreEGFP/+; Rosa26‐EYFP^loxp/+ mice showed that nearly all HCs experiencing Prox1 expression were OHCs. Surprisingly, these HCs still matured normally with expression of prestin, wild‐type‐like morphology, and uptake of FM4‐64FX dye at adult ages. Conclusions: Our results suggest that the developmental program of cochlear differentiating HCs is refractory to Notch reactivation and that Notch is an upstream regulator of Sox2 and Prox1 in cochlear development. In addition, our results support that Sox2 and Prox1 should not be the main blockers for terminal differentiation of HCs newly regenerated from postnatal cochlear SCs that still maintain Sox2 and Prox1 expression. Developmental Dynamics 241:684–696, 2012. © 2012 Wiley Periodicals, Inc.     

卡那霉素对小鼠耳蜗内毛细胞带状突触数量的影响

目的通过研究卡那霉素对小鼠耳蜗内毛细胞带状突触数量的影响,探讨卡那霉素耳毒性的发病机制。方法实验组昆明小鼠分为6组,每组10只,每日丁胺卡那霉素(400mg/kg)进行肌肉注射,并于第0d、第3d、第7d、第10d、第14d、和第21d取耳蜗基底膜顶回作为标本。对照组(每组10只)采用等体积生理盐水肌肉注射。使用免疫荧光双标法对耳蜗内毛细胞带状突触前膜RIBEYE蛋白和突触后膜GluR2&3蛋白进行标记,激光共聚焦显微镜对耳蜗基底膜顶回进行光学连续切片,运用3dMax8.0软件对带状突触进行三维建模及重构,并观察带状突触形态变化和计算其数量改变。结果所有小鼠耳蜗内毛细胞轮廓完整,但内毛细胞带状突触数量存在差异。与生理盐水对照组相比,在卡那霉素注射初期带状突触数量未见明显变化,给药第7d时内毛细胞带状突触数量显著增加,第21d显著下降。结论卡那霉素连续作用21d,耳蜗内毛细胞带状突触数量呈先增高后降低的趋势。     

Relationship between stiffness,internal cell pressure and shape of outer hair cells isolated from the guinea-pig hearing organ

The mechanical properties of outer hair cells are of importance for normal hearing, and it has been shown that damage of the cells can lead to a reduction in the hearing sensitivity. In this study, we measured the stiffness of isolated outer hair cells in hyper- and hypotonic conditions, and examined the change in stiffness in relation to the corresponding changes in internal cell pressure and cell shape. The results showed that the axial stiffness of isolated outer hair cells (30–90 μm in length, 8–12 μm in diameter), ranging from 0.13–5.39 mN m^?1, was inversely related to cell length. Exposure to hyper- and hypotonic external media with a small percentage change in osmolality caused a similar magnitude of change in cell length and cell diameter, but an average 60% change in cell stiffness. Therefore, a moderate osmotic change in the external medium can lead to a significant alteration in cell stiffness. The findings thus indicate an important contribution of internal cell pressure to cell stiffness.     

雷公藤甲素对2型糖尿病小鼠耳蜗毛细胞的保护作用

目的：探讨雷公藤甲素对2 型糖尿病小鼠耳蜗毛细胞的保护作用及机制。方法：选取 Balb/c 雄性小鼠,随 机分为正常组、糖尿病组和雷公藤甲素组。制备2 型糖尿病小鼠模型后,雷公藤甲素组给予雷公藤甲素0.1 mg/kg 灌胃,正常组和糖尿病组小鼠均给予等体积生理盐水灌胃。观察3 组小鼠耳蜗毛细胞的变化,检测耳蜗毛细胞内 氧化应激相关信号通路、抗氧化蛋白及凋亡分子的表达变化。结果：糖尿病组和雷公藤甲素组耳蜗毛细胞均有不 同程度的丢失,且雷公藤甲素组耳蜗毛细胞的丢失率小于糖尿病组。雷公藤甲素组小鼠耳蜗毛细胞中的p-ERK、 E2 核因子相关因子2（Nrf2）、硫氧还蛋白（Trx）表达量及Erk 磷酸化水平高于糖尿病组, JNK磷酸化水平和凋 亡分子cleaved-caspase-3 的蛋白表达量低于糖尿病组。结论：雷公藤甲素可以减缓糖尿病小鼠耳蜗毛细胞凋亡, 其机制与上调ERK、Nrf2 和Trx 的表达,下调JNK信号,抑制凋亡分子cleaved-caspase-3 的表达有关,有望成为 治疗2 型糖尿病耳蜗病变的有效药物。     

Effect of bone morphogenetic protein-2 on proliferation and apoptosis of gastric cancer cells

Objective: To investigate the effects of bone morphogenetic protein-2 (BMP-2) on the proliferation, differentiation and apoptosis of normal human gastric mucosal cells and gastric cancer cells.Methods: Poorly differentiated gastric cancer BGC823 cells, moderately differentiated gastric cancer cells and normal human gastric mucosal epithelial GES-1 cells were independently treated with recombinant human BMP-2 or its inhibitor Noggin. MTT assay was performed to detect the proliferation, flow cytometry done to measure the cell cycle and apoptosis and immunohistochemistry carried out to determine the expression of cyclin-dependent kinase 4 (CDK4).Results: BMP-2 exerted inhibitory effect on the growth of all types of cells and the inhibition become more evident with the increase of BMP-2 dose. After treatment with 200 ng/ml BMP-2, cancer cells arrested in G1 phase and those in S phase reduced. Gastric cancer cells had higher CDK4 expression than GES-1 cells. BMP-2 decreased CDK-4 expression in cancer cells but had no influence in GES-1 cells. Noggin conferred promotive effect on the growth of 3 types of cells. In 2 types of cancer cells, treatment with 2000 ng/ml Noggin significantly increased the proportion of cells in S phase but reduced that in G1 phase. However, Noggin did not affect the cell cycle of GES-1 cells. The CDK4 expression was markedly increased in 2 types of cancer cells but that of GES-1 remained unchanged after treatment with 2000 ng/ml Noggin.Conclusions: BMP-2 may inhibit the proliferation of both normal and malignant gastric epithelial cells, down-regulate CDK4 expression in gastric cancer cells and arrest gastric cancer cells in G1-phase in cell cycle. Through antagonizing BMP-2, Noggin, may accelerate the proliferation of gastric cancer cells. Thus, the abnormality of BMP signaling pathway may play an important role in the pathogenesis of gastric cancer.     

骨形态发生蛋白2及碱性成纤维生长因子2对大鼠骨髓间充质干细胞膜片增殖和成骨分化的影响

文题释义：细胞膜片技术：是在体外接种培养高密度的细胞,使其相互融合生长至100%而形成的透明致密膜状物。该技术不需要胰酶消化即可收集细胞,因此保留了大量的胞外基质、细胞间连接以及细胞-基质连接等结构。目前细胞膜片技术已成为组织工程领域的研究热点,已被推广应用于牙周膜、角膜、心脏、软骨、食管等多种组织器官修复。成骨细胞：主要由内外骨膜和间充质始祖细胞分化而来,在复杂的骨形成过程中发挥着主要的功能,承担着骨基质的合成、分泌和矿化。骨髓间充质干细胞具有多向分化潜能,能定向分化为成骨细胞,其成骨分化过程可受多种因素的影响,如细胞因子的调控、遗传因素和激素水平等。背景：现阶段骨形态发生蛋白2和碱性成纤维生长因子2对骨髓间充质干细胞膜片增殖、成骨分化的影响和作用机制还尚未可知,如何将生长因子与组织工程细胞膜片技术相整合,最终将其用于骨缺损修复具有重要意义。目的：探讨单独及联合应用骨形态发生蛋白2和碱性成纤维生长因子2对骨髓间充质干细胞膜片增殖和成骨分化的影响。方法：体外分离培养鉴定SD大鼠骨髓间充质干细胞并构建细胞膜片,选用不同质量浓度的骨形态发生蛋白2和碱性成纤维生长因子2单独及联合诱导骨髓间充质干细胞膜片,CCK-8法结合碱性磷酸酶活性检测确定2种因子促进膜片增殖和成骨分化的最佳有效质量浓度;然后对骨髓间充质干细胞膜片进行成骨诱导,通过大体及显微镜观察、Vonkossa染色、茜素红染色、RT-PCR检测相关成骨标志物来评估诱导效果。结果与结论：单独应用骨形态发生蛋白2可增强骨髓间充质干细胞膜片的碱性磷酸酶活性,最佳质量浓度为100 μg/L(P < 0.001),单独应用碱性成纤维生长因子2能加速骨髓间充质干细胞膜片的增殖,最佳质量浓度为20 μg/L(P < 0.001),而联合应用既可以促进膜片增殖又能提高其碱性磷酸酶活性(P < 0.001);经成骨诱导后,4组膜片在形态学上无明显差异,均能诱导骨髓间充质干细胞膜片的成骨分化,其中联合组钙结节最明显(P < 0.001),可显著促进膜片晚期成骨分化并抑制其早期成骨分化,具有明显的协同促进作用(P < 0.001)。结果表明,骨形态发生蛋白2和碱性成纤维生长因子2联合应用时具有协同作用,既可以促进骨髓间充质干细胞膜片增殖,又能显著增强其成骨诱导能力。ORCID: 0000-0003-1918-579X(何惠宇)中国组织工程研究杂志出版内容重点：干细胞;骨髓干细胞;造血干细胞;脂肪干细胞;肿瘤干细胞;胚胎干细胞;脐带脐血干细胞;干细胞诱导;干细胞分化;组织工程     

Islets of Langerhans from prohormone convertase‐2 knockout mice show α‐cell hyperplasia and tumorigenesis with elevated α‐cell neogenesis

Antagonism of the effects of glucagon as an adjunct therapy with other glucose‐lowering drugs in the chronic treatment of diabetes has been suggested to aggressively control blood glucose levels. Antagonism of glucagon effects, by targeting glucagon secretion or disabling the glucagon receptor, is associated with α‐cell hyperplasia. We evaluated the influence of total glucagon withdrawal on islets of Langerhans using prohormone convertase‐2 knockout mice (PC2‐ko), in which α‐cell hyperplasia is present from a young age and persists throughout life, in order to understand whether or not sustained glucagon deficit would lead to islet tumorigenesis. PC2‐ko and wild‐type (WT) mice were maintained drug‐free, and cohorts of these groups sampled at 3, 12 and 18 months for plasma biochemical and morphological (histological, immunohistochemical, electron microscopical and image analytical) assessments. WT mice showed no islet tumours up to termination of the study, but PC2‐ko animals displayed marked changes in islet morphology from α‐cell hypertrophy/hyperplasia/atypical hyperplasia, to adenomas and carcinomas, these latter being first encountered at 6–8 months. Islet hyperplasias and tumours primarily consisted of α‐cells associated to varying degrees with other islet endocrine cell types. In addition to substantial increases in islet neoplasia, increased α‐cell neogenesis associated primarily with pancreatic duct(ule)s was present. We conclude that absolute blockade of the glucagon signal results in tumorigenesis and that the PC2‐ko mouse represents a valuable model for investigation of islet tumours and pancreatic ductal neogenesis.     

Analyses of H-2 restriction specificity of helper T cells in fully allogeneic bone marrow chimera in mice

Using irradiation bone marrow chimeras to analyze restriction specificity of helper T cells, we found that recipient H-2 type dictated the H-2 type which the T cells recognize as self (adaptive differentiation). T cells from (H-2b----H-2k) chimeras cooperate with non-T cells bearing Iak to generate a vigorous PFC response to sheep erythrocytes (SRBC) in vitro, but not with genetically identical H-2b cells. However, when T cells from the chimeras and H-2b non-T cells were adoptively transferred into irradiated (donor X recipient) F1 mice with SRBC, marked responses were seen in recipient spleens where radio-resistant F1 macrophages might exist and act as antigen presenting cells (APC). From these in vitro and in vivo observations, we considered that in the primary antibody response to a T dependent antigen such as SRBC, only T cell-macrophage (APC) matching is required. In contrast, when T cells from H-2 incompatible chimeras which had been primed with SRBC in vivo were analyzed in vitro, these cells cooperated also with H-2b non-T cells. These findings indicate that there may be two separate stages of T cell differentiation during which the self restriction specificity is acquired: one appears to be responsive to intrathymic influences and is not associated with antigenic stimuli, and the other shows signs of being responsive to post-thymic stimuli and of involving antigenic presentation. Moreover, the latter appears to utilize the influence of donor type macrophages.     

BCL-2 family proteins in peripheral T-cell lymphomas: correlation with tumour apoptosis and proliferation

The present study investigated expression levels of the anti-apoptotic proteins BCL-2, BCL-XL and MCL-1 and the pro-apoptotic proteins BAX and BCL-XS in a series of 112 peripheral T-cell lymphomas (PTCLs) classified according to the WHO classification. Using immunohistochemical methods and a 10% cut-off, each protein was detected in a subset of PTCLs: BCL-2 in 46%, BCL-XS in 49%, BAX in 57%, BCL-XL in 57%, and MCL-1 in 65%. The mean percentage of positive cells for these proteins varied significantly among the PTCL types. Only two types of PTCL, ALK-positive anaplastic large cell lymphoma (ALCL) and enteropathy-type T-cell lymphoma, had a distinctive pattern of expression; all were BCL-2-negative and MCL-1-positive. The mean percentage of BAX-positive and BCL-XS-positive tumour cells was higher in ALK-positive ALCL than in ALK-negative ALCL or other types of PTCL (p = 0.06 and p = 0.01, respectively, Kruskal-Wallis test). MCL-1 was detected significantly more frequently (p = 0.01, chi-square test) and at higher levels (p = 0.0001, Kruskal-Wallis test) in ALK-positive ALCL and ALK-negative ALCL than in other PTCL types. The apoptotic rate, evaluated by the TUNEL assay, correlated inversely with BCL-2 expression (p = 0.035). The proliferation index, assessed by the MIB-1 antibody, correlated with expression levels of MCL-1 (R = 0.42, p = 0.003), BCL-2 (R = 0.32, p = 0.027), BAX (R = 0.33, p = 0.014), and BCL-XL (R = 0.34, p = 0.015) (Spearman rank). In conclusion, BCL-2 family proteins are expressed by a subset of PTCLs and their levels correlate with some histological types, apoptotic rate, and proliferation index. Expression of these proteins may explain the poor response of many types of PTCL to standard chemotherapy. These proteins may also provide novel targets for experimental therapy.     

骨巨细胞瘤中Skp2、p27及E2F-1的表达及意义

目的研究骨巨细胞瘤中Skp2(S期激酶相关蛋白2)、p27(周期素依赖性蛋白激酶抑制因子)及E2F-1(细胞周期相关性转录因子家族成员)的表达并探讨其与放射学分期、肿瘤复发等关系。方法运用免疫组化SP法检测44例骨巨细胞瘤中Skp2、p27及E2F-1的表达情况。结果 Skp2、p27及E2F-1的阳性率分别为65.91%3、8.64%和63.64%,在影像学分期1型、2型3、型中的阳性率分别为50%、64.29%、100%(P<0.05),60%、28.57%、10%(P<0.05),50%、71.43%、80%(P>0.05)。Skp2、p27及E2F-1在复发组与未复发组的阳性率分别为91.67%、56.25%(P<0.05),8.33%、50%(P<0.05),75.00%、59.38%(P>0.05)。Skp2、骨皮质破坏或软组织浸润、手术方式以及p27对复发均有明显影响,其中前两者是骨巨细胞瘤复发的危险因素,后两者(截骨的手术方式、p27)则是骨巨细胞瘤复发的保护因素。Skp2与p27的表达呈负相关(P<0.05)。结论在骨巨细胞瘤中,Skp2与p27的表达均与骨巨细胞瘤的复发有关,二者在骨巨细胞...     

Analyses of Ia restriction specificity of helper T cells in H-2 subregion compatible bone marrow chimera in mice

Using irradiation bone marrow chimeras which had partial compatibility in H-2 subregions between donor and recipient mice, we found that H-2I matching was sufficient for the chimeras to generate anti-sheep erythrocyte plaque-forming cell (PFC) responses. In such chimeras, T cells appeared to encounter appropriate partner cells bearing the same Ia antigens as those which they had learned to recognize as self in the recipient micro-environment. Furthermore, the PFC number seen in I-A compatible chimeras was only about half of that seen in I-A, I-E compatible chimeras, suggesting the existence of two independent subpopulations of helper T cells. When incompatibility of donor and recipient mice existed on the left side of the H-2I region, the responses were very weak. However, even in such chimeras, marked responses were observed for both IgM and IgG type PFC following a sufficient period after immunization. This observation appears to indicate the existence of a minor subpopulation of helper T cells which can expand and interact effectively with antigen presenting cells of donor type.     

Heterogeneity of vascular and progenitor cell compartments in tumours from MMTV-PyVmT transgenic mice during mammary cancer progression

Transgenic mice are important tools for our study of breast cancer pathobiology. In order to evaluate changes in cell phenotype with breast cancer progression, we examined vascular and progenitor cell characteristics in tumours derived from MMTV-PyVmT mice. We performed dual-immunofluorescence staining for Tie2, pTie2Y1100, VEGFR2 and PDGFR-β and the pan-endothelial marker PECAM-1 (CD31) in 39 tumours from MMTV-PyVmT transgenic mice grouped by nuclear grade and tumour morphology. Immunohistochemical staining for Aldh1a1 was performed in MMTV-PyVmT-derived tumours and in non-transgenic mouse mammary glands. Tumour blood vessels were heterogeneous in all samples analysed, with the proportion of Tie2-, pTie2 (Y1100)-, VEGFR2- and PDGFR-β-positive tumour blood vessels ranging from 18-98%, 7-40%, 19-86% and 16-94% respectively. We observed a statistically significant difference in vascular pTie2Y1100 levels between low-nuclear-grade tumours and intermediate-/high-nuclear-grade tumours (P=0.03) and an increase in the proportion of PDGFR-β-positive tumour blood vessels in tumours with high vs. Intermediate-nuclear grade tumours (P<0.01). Aldh1a1-positive mammary epithelial cells were observed in the terminal end buds of non-transgenic mammary glands and Aldh1a1-positive mammary tumour cells were observed in tumours from MMTV-PyVmT transgenic mice. We observed a decrease in the average number of Aldh1a1-positive cells in tumours with a non-invasive vs. solid morphology (P=0.03), and in the average number of Aldh1a1-positive mammary tumour cells in low vs. intermediate and low vs. High-nuclear grade tumours (P<0.001). Our findings suggest heterogeneous expression of several molecules important for tumour angiogenesis and tumour progression that are currently under investigation as therapeutic targets for metastatic breast cancer.     

Testin interacts with vangl2 genetically to regulate inner ear sensory cell orientation and the normal development of the female reproductive tract in mice

Results: We identified Testin as a Vangl2‐interacting protein through a 2‐hybrid screen with a cochlea cDNA library. Testin is enriched to cell–cell boundaries in the presence of Vangl2 in cultured cells. Genetic inactivation of Testin leads to abnormal hair cell orientation in the vestibule and cellular patterning defects in the cochlea. In addition, Testin genetically interacts with Vangl2 to regulate hair cell orientation in the cochlea and the opening of the vaginal tract. 相似文献   

转化生长因子β和骨形成蛋白2联合诱导小鼠成骨细胞系MC3T3-E1细胞的增殖与分化

背景:生长因子是骨组织形成、改建、修复的关键要素之一,多种生长因子联合诱导骨干细胞成骨分化相较于单一生长因子具有一定的优势,但是何种类型的联合、什么样的浓度组合才能发挥最佳的诱导作用?目前该方向研究较少.目的:探索转化生长因子β和骨形成蛋白2联合诱导对小鼠MC3T3-E1细胞增殖和分化的影响.方法:将不同质量浓度的转化...     

CD8+ T cell responses to human immunodeficiency viruses type 2 (HIV-2) and type 1 (HIV-1) gag proteins are distinguishable by magnitude and breadth but not cellular phenotype

The mechanisms underlying the relatively slow progression of human immunodeficiency virus type 2 (HIV-2) compared with HIV-1 infection are undefined and could be a result of more effective immune responses. We used HIV-2 and HIV-1 IFN-gamma enzyme-linked immunospot assays to evaluate CD8(+) T cell responses in antiretroviral-naive HIV-2- ('HIV-2(+)') and HIV-1-infected ('HIV-1(+)') individuals. Gag-specific responses were detected in the majority of HIV-2(+) and HIV-1(+) subjects. Overlapping gag peptide analysis indicated a significantly greater magnitude and breadth of responses in the HIV-1(+) cohort, and this difference was attributable to low responses in HIV-2(+) subjects with undetectable viral load (medians 2107 and 512 spot-forming units per 10(6) PBMC, respectively, p=0.007). We investigated the phenotype of viral epitope-specific CD8(+) T cells identified with HLA-B53- and HLA-B58-peptide tetramers (8 HIV-2(+), 11 HIV-1(+) subjects). HIV-2-specific CD8(+) T cells were predominantly CD27(+) CD45RA(-), and only a minority expressed perforin. The limited breadth and low frequency of CD8(+) T cell responses to HIV-2 gag in aviremic HIV-2(+) subjects suggests that these responses reflect antigen load in plasma, as is the case in HIV-1 infection. Immune control of HIV-2 does not appear to be related to the frequency of perforin-expressing virus-specific CD8(+) T cells.     

The effect of leukocyte-platelet-rich fibrin on bone morphogenetic protein-2 and insulin-like growth factor-1 levels in patients with chronic periodontitis: a randomized split mouth clinical trail

The present study evaluates the effects of leukocyte-platelet-rich fibrin (L-PRF) combined with open flap debridement (OFD) on clinical parameters and growth factors levels (GFL) in chronic periodontitis (CP) patients. This trial was registered at clinicaltrials.gov as NCT02594605. 16 patients (32 sites) with chronic periodontitis who had at least two areas of horizontal bone loss, were treated with OFD alone or L-PRF with OFD (OFD?+?L-PRF). GFL in gingival crevicular fluid (GCF) were analyzed at baseline, 1?week, 2?weeks and 4?weeks after operation. Probing depth (PD) and clinical attachment level (CAL) were measured at baseline and 6?months postoperatively. PD reduction and CAL gain were significantly higher in the OFD?+?L-PRF sites than in OFD sites. OFD?+?L-PRF group showed significantly increased bone morphogenetic protein-2 and insulin-like growth factor-1 at 2?weeks compared with baseline. L-PRF combined with OFD significantly increases GFL and thus, it enhances the periodontal healing on CP patients.     

Critical role of the NKG2D receptor for NK cell‐mediated control and immune escape of B‐cell lymphoma

Little is known on the control of lymphomas by NK cells. Here, we study the role of the NK group 2D (NKG2D) receptor for the immunosurveillance of lymphoma. By using transplantable tumors as well as a λ‐myc‐transgenic model of endogenously arising lymphoma and NKG2D‐deficient mice, we show that NK cells eliminate tumor cells in vivo after receiving two signals. One step involved the activation of NK cells giving rise to IFN‐γ expression, which was effected by MHCI^low tumor cells or DCs. However, this was necessary but not sufficient to mediate cytotoxicity. Triggering cytotoxicity additionally required a second step, which could be mediated by engagement of the NKG2D receptor. Thus, NKG2D‐deficient NK cells could become activated in vivo, but they were not able to reject transplanted lymphomas or to degranulate in animals bearing autochthonous lymphomas. Tumor growth in NKG2D‐deficient λ‐myc‐transgenic mice was significantly accelerated compared to NKG2D‐competent animals. Whereas the latter developed tumors that lost expression of NKG2D ligands (NKG2D‐L) in late disease stages, this did not occur in NKG2D‐deficient mice. This indicates that NK cells and the NKG2D receptor play a role for control of lymphomas and that selection for NKG2D‐L loss mutants provides a mechanism of tumor escape.     

Susceptibility of T cell receptor-alpha chain knock-out mice to ultraviolet B light and fluorouracil: a novel model for drug-induced cutaneous lupus erythematosus

The anticancer agent 5-fluorouracil (FU) frequently induces cutaneous lupus erythematosus (LE) lesions on sun exposed sites. Based on this observation, we have tried to establish a cutaneous LE model of C57BL/6 J (B6) mice, B6 T cell receptor (TCR)-alpha(-/-) mice and B6 TCR-delta(-/-) mice treated with FU and/or ultraviolet B light (UVBL) in order to clarify the role of T cells and the cytokine profile of cutaneous lupus lesions. Cutaneous LE-like skin lesions could be induced in TCR-alpha(-/-) mice with low FU (0.2 mg) plus UVBL, and in B6 mice treated with a high dose of FU (2.0 mg) plus UVBL. In contrast, low FU plus UVBL induced such skin lesions in TCR-delta(-/-) mice at a very low incidence. Specifically, the skin lesions of TCR-alpha(-/-) mice with low FU plus UVBL appeared more rapidly and were more severe than lesions in B6 mice. The former had the common characteristic features of human chronic cutaneous LE such as typical histology, positive IgG at the dermoepidermal junction, low antinuclear antibody and low mortality. Furthermore, a Th1 response was induced in the development of drug-induced cutaneous LE. FU and UVBL-induced cutaneous LE-like eruption is an excellent model for better understanding the pathomechanisms of skin lesion development in LE.