增龄相关听力丧失小鼠耳蜗毛细胞表型与基因突变的关系

目的 观察增龄相关听力丧失 (AHL)小鼠耳蜗毛细胞病理改变的超微结构 ,为老年性聋病理生理及临床表现+基因表型提供形态学改变依据。方法 应用扫描电镜 (SEM)观察BALB/c小鼠耳蜗Corti器毛细胞的超微结构改变 ,测定动物ABR反应阈值。DNA提取PCR扩增分析基因型。结果 6月龄BALB/c小鼠耳蜗底回内外毛细胞有连续的缺失 ,静纤毛束有融合、散乱、变短和失去劲度。ABR阈值呈中到重度听力损失。证明种系特异的Ahl基因位点和基因功能。结论 耳蜗毛细胞静纤毛束融合、散乱、变短是老年性聋早期的主要病理改变 ,mdfw与Ah1的表现形式是同一基因位点 ,可能与myosin基因突变有关。

MicroRNA Expression Profiles and MiR-10a Target in Anti-benzo[a] pyrene-7,8-diol-9,10-epoxide-transformed Human 16HBE Cells

Objective To screen miRNA profiles of malignantly transformed human bronchial epithelial cells, 16HBE-T, induced by anti-benzo[a]pyrene-trans-7,8-diol-9,10-epoxide （anti-BPDE）, and to analyze putative miR-10a targets in 16HBE-T. Methods A novel microarray platform was employed to screen miRNA profiles of 16HBE-T cells transformed by anti-BPDE. Microarray data for miR-10a and miR-320 were validated using quantitative real time polymerase chain reaction （QRT-PCR）. The expression of a putative target for miR-10a, HOXA1, was analyzed by reverse transcription polymerase chain reaction （RT-PCR） and QRT-PCR. Results In comparison with the vehicle-treated cells （16HBE-N）, 16HBE-T exhibited differential expression of 54 miRNAs, in which, 45 were over-expressed and 9 were down-regulated. The five most highly expressed miRNAs were miR-494, miR-320, miR-498, miR-129, and miR-106a. The lowest expressed miRNAs were miR-10a, miR-493-5p, and miR-363＊. Three members of miR-17-92 cluster, miR-17-5p, miR-20a, and miR-92, showed significantly higher abundance in 16BHE-T as miR-21, miR-141, miR-27a, miR-27b, miR-16 and miRNAs of the let-7 family. The putative target for miR-10a, HOXA1 mRNA was up-regulated 3-9-fold in 16HBE-T, as compared with 16HBE-N. Conclusion The findings of the study provide information on differentially expressed miRNA in malignant 16HBE-T, and also suggest a potential role of these miRNAs in cell transformation induced by anti-BPDE. HOXA1 is similarly up-regulated, suggesting that miR-10a is associated with the process of HOXA 1-mediated transformation.

Fine Mapping of a Deafness Mutation hml on Mouse Chromosome 10

Objective To map a mouse deafness gene, identify the underlying mutation and develop a mouse model for human deafness. Methods Genetic linkage cross and genome scan were used to map a novel mutation named hypoplasia of the membranous labyrinth (hml), which causes hearing loss in mutant mice. Results ① hml was mapped on mouse Chr 10 (～43 cM from the centromere) suggests that the homologous human gene is on 12q22-q24, which was defined on the basis of known mouse-human homologies (OMIM, 2004). ② This study has generated 25 polymorphic microsatellite markers, placed 3 known human genes in the correct order in a high-resolution mouse map and narrowed the hml candidate gene region to a 500 kb area.

小鼠10号染色体上致聋突变基因hml的精确定位(英文)

目的 定位小鼠致聋基因 ,识别决定其性状的有关突变 ,为人类耳聋基因研究提供动物模型。方法 利用全基因组扫描来定位名为hml可致小鼠听力丧失突变基因。结果 ①hml基因定位在小鼠 10号染色体上 ,距中心粒约4 3cM处。根据已知的鼠 人同源同线性特点 ,提示人的同源基因位于 12 q2 2 -q2 4 ;②获得了 2 5个多态性微卫星标记 ,通过高分辨的小鼠图谱将 3个已知人类基因进行了正确排列 ,并将hml侯选基因限定在一个 5 0 0kb的区域内。

Delivery of Cas9 Protein into Mouse Zygotes through a Series of Electroporation Dramatically Increases the Efficiency of Model Creation

Previously we established Zygote Electroporation of Nucleases（ZEN） technology as an efficient and high-throughput way to generate genetically modified mouse models.However,there were significant variations of the targeting efficiency among different genomic loci using our previously published protocol.In this study,we improved the ZEN technology by delivering Cas9 protein into mouse zygotes through a series of electroporation.Using this approach,we were able to introduce precise nucleotide substitutions,large segment deletion and short segment insertion into targeted loci with high efficiency.

Mapping of genetic modifiers of Plcd1 in scant hair mice(snthr^(1Bao))

The scant hair mutant mouse(locus symbol:snthr1Bao) is a recessive mutation that originated in an ethylnitrosourea chemical carcinogenesis study using the DBA/2J inbred strain.The gene responsible for the mutation was previously determined to be phospholipase C,delta 1(Plcd1;mutant allele symbol Plcd1snthr1Bao).To map the modifiers of Plcd1,an intercross(DBA/2J-snthr1Bao/snthr1Bao × C57BL/6J+/+) was conducted.The F2 mutant progeny exhibited a variety of alopecia phenotypes;all F2 mutants(n=507) were classified into 3 groups(mild,moderate,and severe alopecia) and genotyped based on 96 microsatellites.A major QTL was identified on mouse chromosome(mChr) 15 at 12 cM with an LOD score greater than 7(P < 0.0001).Three minor QTLs were detected on mChr 2,5,and 7 at 40,84 and 48 cM,respectively.The QTLs on mChr 7 and 15 were associated with minor alopecia while the QTLs on mChr 2 and 5 were associated with moderate to severe alopecia.No antagonistic or synergistic effects among or between the 4 QTLs were found.Integrating the functions of the 4 potential regulatory QTLs and mutant Plcd1snthr1Bao,we found that these QTLs might contribute to variations of scant hair severity by altering the Ca2+ signal pathways in mouse skin.

Human allograft rejection in humanized mice： a historica perspective

Basic research in transplantation immunology has relied primarily on rodent models. Experimentation with rodents has laid the foundation for our basic understanding of the biological events that precipitate rejection of non-self or allogeneic tissue transplants and supported the development of novel strategies to specifically suppress allogeneic immune responses, However, translation of these studies to the clinic has met with limited success, emphasizing the need for new models that focus on human immune responses to allogeneic tissues. Humanized mouse models are an exciting alternative that permits investigation of the rejection of human tissues mediated by human immune cells without putting patients at risk. However, the use of humanized mice is complicated by a diversity of protocols and approaches, including the large number of immunodeficient mouse strains available, the choice of tissue to transplant and the specific human immune cell populations that can be engrafted. Here, we present a historical perspective on the study of allograft rejection in humanized mice and discuss the use of these novel model systems in transplant biology.

Towards smart self-clearing glaucoma drainage device

For patients who are unresponsive to pharmacological treatments of glaucoma,an implantable glaucoma drainage devices(GDD)are often used to manage the intraocular pressure.However,the microscale channel that removes excess aqueous humor from the anterior chamber often gets obstructed due to biofouling,which necessitates additional surgical intervention.Here we demonstrate the proof-of-concept for smart self-clearing GDD by integrating magnetic microactuators inside the drainage tube of GDD.The magnetic microactuators can be controlled using externally applied magnetic fields to mechanically clear biofouling-based obstruction,thereby eliminating the need for surgical intervention.In this work,our prototype magnetic microactuators were fabricated using low-cost maskless photolithography to expedite design iteration.The fabricated devices were evaluated for their static and dynamic mechanical responses.Using transient numerical analysis,the fluid–structure interaction of our microactuator inside a microtube was characterized to better understand the amount of shear force generated by the device motion.Finally,the anti-biofouling performance of our device was evaluated using fluorescein isothiocyanate labeled bovine serum albumin.The microactuators were effective in removing proteinaceous film deposited on device surface as well as on the inner surface of the microchannel,which supports our hypothesis that a smart self-clearing GDD may be possible by integrating microfabricated magnetic actuators in chronically implanted microtubes.

Nature:科学家鉴别出调节机体睡眠的两个关键基因

近日，刊登在国际杂志Nature上的一项研究报告中，来自西南医学中心等机构的研究人员通过研究鉴别出了两个关键的核心基因，这两个基因能够帮助调节机体深度睡眠和做梦的水平，相关研究或为阐明相关的基因控制睡眠的网络提供新的线索。此前研究者通过对小鼠进行研究发现了能够控制机体快速眼动睡眠的基因，同时该基因还能够诱导深度睡眠。而第二个基因能够控制机体对快速眼动睡眠的需求量，相关研究为科学家们提供了一个关键的切入点来帮助解释睡眠工作的机制，同时研究者还鉴别出了治疗睡眠障碍的潜在靶点。