Dipping your feet in the water: podocytes in urine

Podocyte injury and loss plays an important role in the pathogenesis and progression of many kidney diseases. Studies have shown that podocyte-related markers and products can be detected in the urine of patients with glomerular diseases such as focal segmental glomerulosclerosis, IgA nephropathy, lupus nephritis, diabetic nephropathy and pre-eclampsia. Therefore, detecting the loss of podocytes in the urine provides a useful noninvasive technique of gathering information about the disease type and/or activity of glomerular diseases. Currently, urine podocyte-related protein markers, mRNA, microRNA and exosomes have been used with varying degrees of success to study glomerular diseases. The determination of urinary podocyte loss may become an important noninvasive tool in the evaluation of glomerular diseases.     

树突状细胞外泌体诱导间充质干细胞向成骨细胞分化

本研究观察人树突状细胞（dendriticcells,DC）来源的外泌体（DC—derivedexosome,DCex）对人骨髓间充质干细胞（mesenchymalstemcells,MSC）成骨分化的影响。采用超速离心法从树突状细胞培养上清中获取DCex,应用电子显微镜观察DCex形态并通过流式细胞术检测和鉴定其细胞来源。取第3代MSC,设3组培养诱导体系：①对照组：d—MEM基础培养液组;②实验组：d—MEM基础培养液＋DCex（10μg/m1）组;③α-MEM基础培养液＋标准诱导剂组。采用荧光实时定量PCR、琼脂糖凝胶电泳检测各组成骨分化转录因子Runx2mRNA的表达情况,并进行碱性磷酸酶（ALP）活性检测。另外,荧光染料DiI标记DCex,应用共聚焦显微镜观察DCex进入MSC的过程。结果显示,在电子显微镜下DCex呈典型的圆形或椭圆形膜层结构,直径为40—100nm,并表达DC细胞的标志物CD83,CD86,CD80和HLA—DR。在DCex处理MSC后6h时,可在共聚焦显微镜下观察到进入到MSC胞质内的DCex,随着作用时间延长,细胞荧光强度增加。按组培养第7天,DCex实验组Runx2表达较对照组增高,差异有统计学显著性（P〈0．05）;MSC培养第14天,DCex组ALP含量OD值与对应蛋白比为2．22±0．27,显著高于阴性对照组（1．20±0．21）（P〈0．01）,但低于标准诱导组（3．22±0．24）（P〈0．05）。结论：DCex可以促进MSC向成骨细胞分化,其且体机制仍需讲一步研穷证实．     

Dendritic Cell-Derived Exosomes Stimulate Stronger CD8^＋ CTL Responses and Antitumor Immunity than Tumor Cell-Derived Exosomes

Exosomes （EXO） derived from dendritic cells （DC） and tumor cells have been used to stimulate antitumor immune responses in animal models and in clinical trials. However, there has been no side-by-side comparison of the stimulatory efficiency of the antitumor immune responses induced by these two commonly used EXO vaccines. In this study, we selected to study the phenotype characteristics of EXO derived from a transfected EG7 tumor cells expressing ovalbumin （OVA） and OVA-pulsed DC by flow cytometry. We compared the stimulatory effect in induction of OVA-specific immune responses between these two types of EXO. We found that OVA protein-pulsed DCOVA-derived EXO （EXODC） can more efficiently stimulate naive OVA-specific CD8^＋ T cell proliferation and differentiation into cytotoxic T lymphocytes in vivo, and induce more efficient antitumor immunity than EG7 tumor cell-derived EXO （EXOEG7）. In addition, we elucidated the important role of the host DC in EXO vaccines that the stimulatory effect of EXO is delivered to T cell responses by the host DC. Therefore, DC-derived EXO may represent a more effective EXO-based vaccine in induction of antitumor immunity. Cellular ＆ Molecular Immunology. 2006;3（3）：205-211.     

肺癌细胞裂解物负载对树突状细胞分泌的exosome诱导抗肿瘤作用的影响

目的为制备高效的胞外体（exosome）肿瘤疫苗提供理论依据。方法用细胞因子诱导培养树突状细胞（DC）,将肺癌细胞裂解物负载DC,提取exosome用exosome活化T细胞（负载组）,以未负载DC的exosome（未负载组）及肺癌细胞裂解物负载DC（DC组）活化的T细胞为对照,MTr法检测三组肺癌细胞的杀伤率。结果exosome中有HSP70、HLA及CEA表达。活化T细胞／肺癌细胞为25：1、10：1、5：1时负载组杀伤率均明显高于未负载组及DC组（P均〈0．05）。结论肺癌细胞裂解物负载能增强DC分泌的exosome诱导的抗肿瘤作用;本研究为制备高效的exosome肿瘤疫苗提供了理论依据。     

丹皮酚通过抑制p38 MAPK/N-SMase2通路减少脂多糖诱导的THP-1细胞外泌体分泌

目的探讨丹皮酚抑制脂多糖诱导后THP-1细胞分泌外泌体的作用及机制。方法超速离心法提取外泌体,透射电镜(TEM)观察外泌体形态,Western blot检测标志蛋白Alix、TSG101、CD9和CD63,动态光散射检测外泌体粒径。CCK-8检测细胞存活率,BCA法检测外泌体蛋白量,Western blot检测N-SMase2、p-p38 MAPK蛋白水平。结果超速离心法获得的微囊泡结构物具有完整清晰茶托样膜,直径众数为130 nm,含标志性蛋白Alix、TSG101、CD9和CD63,鉴定为外泌体。丹皮酚(120、60及30μmol/L)可降低脂多糖(1 mg/L)诱导的THP-1细胞分泌外泌体,减少N-SMase2蛋白表达,抑制p38 MAPK磷酸化。结论丹皮酚抑制THP-1细胞外泌体分泌,该作用与抑制p38 MAPK/N-SMase2通路有关。     

Mesenchymal stem cell-derived exosomes attenuate phosgene-induced acute lung injury in rats

Objective: We have previously found that mesenchymal stem cell (MSC) therapy can ameliorate phosgene-induced acute lung injury (ALI). Moreover, exosomes can be used as a cell-free alternative therapy. In the present study, we aimed to assess the effect of MSC-derived exosomes on phosgene-induced ALI.

Methods: MSC-derived exosomes were isolated from MSCs through ultracentrifugation. Sprague-Dawley (SD) rats were exposed to phosgene at 8.33?g/m³ for 5?min. MSC-derived exosomes were intratracheally administered and rats were sacrificed at the time points of 6, 24 and 48?h.

Results: Compared with the phosgene group, MSC-derived exosomes reversed respiratory function alterations, showing increased levels of TV, PIF, PEF and EF50 as well as decreased levels of RI and EEP. Furthermore, MSC-derived exosomes improved pathological alterations and reduced wet-to-dry ratio and total protein content in BALF. MSC-derived exosomes reduced the levels of TNF-α, IL-1β and IL-6 and increased the IL-10 level in BALF and plasma. MSC-derived exosomes suppressed the MMP-9 level and increased the SP-C level.

Conclusions: MSC-derived exosomes exerted beneficial effects on phosgene-induced ALI via modulating inflammation, inhibiting MMP-9 synthesis and elevating SP-C level.