Interfaces between dendritic cells, other immune cells, and nerve fibres in mouse Peyer's patches: potential sites for neuroinvasion in prion diseases

In this study, we examined where immune cells and nerve fibres are located in mouse Peyer's patches, with a view to identifying potential sites for neuroinvasion by prions. Special attention was paid to dendritic cells, viewed as candidate transporters of infectious prion. Double immunofluorescence labellings with anti-CD11c antibody and marker for other immune cells (B cells, T cells, follicular dendritic cells) were carried out and analysed by confocal microscopy on Peyer's patch cryosections. To reveal the extensive ganglionated networks of the myenteric and submucosal plexi and the sparse meshworks of nerve strands, we used antibodies directed against different neurofilament subunits or against glial fibrillary acidic protein. In the suprafollicular dome, dendritic cells connect, via their cytoplasmic extensions, enterocytes with M cells of the follicle-associated epithelium. They are also close to B and T cells. Nerve fibres are detected in the suprafollicular dome, notably in contact with dendritic cells. Similar connections between dendritic cells, T cells, and nerve fibres are seen in the interfollicular region. Germinal centres are not innervated; inside them dendritic cells establish contacts with follicular dendritic cells and with B cells. After immunolabelling of normal prion protein, dendritic cells of the suprafollicular dome are intensely positive labelled.     

考虑STDP学习律的树突整合型神经元网络的放电同步

生物神经网络的同步被认为在大脑神经信息的处理过程中发挥了重要作用。本文以树突整合型(DHH)神经元网络为研究对象,在网络中考虑脉冲时间依赖可塑性(STDP)学习律,分析网络连接概率、外部扰动以及STDP学习律对网络同步性的影响。研究结果表明,STDP学习律对网络同步的影响不仅与连接概率有关,也与外部扰动有关。在兴奋性神经元网络中,连接概率增大可以增强网络的同步,外部扰动增大会减弱网络的同步,且在较大的外部扰动下STDP学习律对网络同步特性的增强作用减弱;而在抑制性DHH神经元网络中,连接概率增大,也可以增强网络的同步,且在较大的连接概率下,外部扰动增大,可以增强网络的同步,而STDP学习律对网络同步的增强作用也更加明显。     

Surface Engineered Polymersomes for Enhanced Modulation of Dendritic Cells During Cardiovascular Immunotherapy

The principle cause of cardiovascular disease (CVD) is atherosclerosis, a chronic inflammatory condition characterized by immunologically complex fatty lesions within the intima of arterial vessel walls. Dendritic cells (DCs) are key regulators of atherosclerotic inflammation, with mature DCs generating pro‐inflammatory signals within vascular lesions and tolerogenic DCs eliciting atheroprotective cytokine profiles and regulatory T‐cell (Treg) activation. Here, the surface chemistry and morphology of synthetic nanocarriers composed of poly(ethylene glycol)‐b‐poly(propylene sulfide) copolymers to enhance the targeted modulation of DCs by transporting the anti‐inflammatory agent 1,25‐dihydroxyvitamin D3‐(aVD) and ApoB‐100‐derived antigenic peptide P210 are engineered. Polymersomes decorated with an optimized surface display and density for a lipid construct of the P‐D2 peptide, which binds CD11c on the DC surface, significantly enhance the cytosolic delivery and resulting immunomodulatory capacity of aVD in vitro. Weekly low‐dose intravenous administration of DC‐targeted, aVD‐loaded polymersomes significantly inhibit atherosclerotic lesion development in high‐fat‐diet‐fed ApoE^?/? mice. The results validate the key role of DC immunomodulation during aVD‐dependent inhibition of atherosclerosis and demonstrate the therapeutic enhancement and dosage lowering capability of cell‐targeted nanotherapy in the treatment of CVD.     

Antigen‐Directed Fabrication of a Multifunctional Nanovaccine with Ultrahigh Antigen Loading Efficiency for Tumor Photothermal‐Immunotherapy

Current antigen‐encapsulated multifunctional nanovaccines for oncotherapy suffer from limited antigen loading efficiency, low yield, tedious manufacture, and systemic toxicity. Here, an antigen‐directed strategy for the fabrication of multifunctional nanovaccine with ultrahigh antigen loading efficiency in a facile way for tumor photothermal‐immunotherapy is shown. As a proof of concept, a model antigen ovalbumin (OVA) is used as a natural carrier to load a representative theranostic agent indocyanine green (ICG). Mixing OVA and ICG in aqueous solution gives the simplest multifunctional nanovaccine so far. The nanovaccine owns antigen loading efficiency of 80.8%, high yield of >90%, intense near‐infrared absorption and fluorescence, excellent reproducibility, good aqueous solubility and stability, and favorable biocompatibility. These merits not only guarantee sensitive labeling/tracking and efficient stimulation of dendritic cells, but also reliable imaging‐guided photothermal‐immunotherapy of tumors and tumor prevention. The proposed strategy provides a facile and robust method for large‐scale and reproducible fabrication of multifunctional nanovaccines with ultrahigh antigen loading efficiency for tumor therapy.     

共担载阿霉素/血红蛋白树枝状介孔硅球的制备及其生物性能研究

实体瘤中普遍存在乏氧现象, 是导致肿瘤对非手术治疗手段抗拒性增加, 降低药物疗效的重要因素。针对这一问题, 本研究采用简单的两相界面法制备了一种小尺寸(65 nm)、单分散、生物稳定性良好的可共载抗癌药物盐酸阿霉素(DOX)和载氧蛋白血红蛋白(Hb)的树枝状介孔硅纳米颗粒(DMSNs)。利用扫描电子显微镜(SEM)、透射电子显微镜(TEM)、动态光散射仪(DLS)和氮气吸附-脱附仪等对材料进行表征。结果表明, 合成的DMSNs纳米颗粒粒径均一、分散性良好, 具有较大的比表面积(654.52 m²/g)和孔容(1.26 cm³/g)以及两套孔道结构(直径2.7 nm和5.4~6.8 nm)。更重要的是, 树枝状介孔层的孔径仅需改变三乙醇胺(TEA)的用量即可调节。药物释放、流式细胞术、激光共聚焦以及细胞毒性等相关实验结果表明, DMSNs可同时装载DOX与Hb, 且具有较高的药物释放能力(75.6%)和持久的释放性能(48 h)。载入血红蛋白后, 其IC₅₀为20.6 μg/mL, 能够有效提高抗癌药物DOX的细胞致死率。因此, 这种小尺寸的树枝状介孔硅球在药物传输和肿瘤治疗方面具有潜在的应用价值。     

树枝状Ag基底的制备及其SERS活性研究

研究了一种表面增强拉曼散射(SERS)活性Ag基底的制备新方法。通过电化学方法和液相生长方法相结合在金属Al表面制备SERS活性Ag膜。用扫描电子显微镜(SEM)表征Ag膜的表面形貌,以结晶紫(C25 H30N3Cl·H2O)为拉曼探针分子,研究了基底的SERS增强效果。研究表明:结晶紫分子吸附在Ag膜表面的SERS强度随电沉积时间的增加呈现先增强后减弱的趋势;进一步的Ag增强剂和引发剂的混合溶液对电沉积Ag膜的浸泡处理可以调节基底Ag膜的结构形态,增强电沉积基底Ag膜的SERS活性。     

负载食管癌抗原肽的脐血树突状细胞诱导杀瘤活性研究

为探讨负载酸洗脱食管癌抗原肽的脐血树突状细胞(DCs)对细胞毒T细胞(CTL)杀伤活性的影响,本研究采用密度梯度离心法分离脐血中的单个核细胞(CBMNC),在重组人粒巨噬细胞集落刺激因子(rhGM-CSF)、重组白介素(rhIL-4)及重组肿瘤坏死因子(rhTNF-a)的配伍作用下,以酸洗脱食管癌抗原肽负载获得分化成熟DCs,利用CytoTox 96试剂盒检测其对特异性CTL的诱导和体外杀伤效应的影响。结果:负载食管癌抗原肽的脐血DCs诱导的CTL对酸洗前食管癌细胞株T.Tn的杀伤率达(78.5±9.5)%,显著高于酸洗后组和各对照组(P<0.05),而对无关肿瘤细胞株Hep2无显著杀伤作用(P<0.05)。结论:负载食管癌抗原肽的脐血DCs体外可诱导CTL产生特异性杀伤效应。本研究为食管癌的免疫治疗提供了新的有效途经。     

The distribution of T lymphocytes,B lymphocytes,and dendritic‐like cells of the anal tonsil in the laboratory shrew,Suncus murinus

We investigated the distribution of T lymphocytes, B lymphocytes, and S‐100 protein‐immunoreactive dendritic‐like in the anal tonsil of the laboratory shrew, Suncus murinus. In adult animals, T lymphocytes were located mainly at the periphery of the anal tonsil, especially around small blood vessels. B lymphocytes were located in the central and subepithelial region of the anal tonsil, which includes primary lymphoid follicles, and in which there are small numbers of scattered T lymphocytes. B and T lymphocytes were distributed over 72.7 and 27.3% of the tonsillar area, respectively. However, their areas of distribution were not clearly distinguished. The areas containing B lymphocytes were enriched in S‐100 protein antibody‐immunoreactive cells, which exhibited a dendritic shape. These S‐100‐positive cells appeared to be identical to the follicular dendritic cells (FDC) seen in the follicles of lymphoid organs. These results suggest that the anal tonsils constitute one of the gut‐associated lymphoid tissues (GALT), and that a function of the anal tonsil includes the capture of intruding antigens that would generate protective antibody responses. Microsc. Res. Tech., 2011. © 2010 Wiley‐Liss, Inc.     

Ultrastructural localization of fructose‐1,6‐bisphosphatase in mouse brain

Fructose‐1,6‐bisphosphatase has been studied in adult mouse brain of different ages using an antibody directed against the liver isoform. The presence of liver fructose‐1,6‐bisphosphatase in cerebellum, cerebral cortex, and hippocampus was assayed using Western blot and different immunocytochemical techniques. Immunocytochemistry with peroxidase reaction product was used to locate fructose‐1,6‐bisphosphatase in both neurons and astrocytes in the same areas, as well as in the rest of the brain, at light and electron microscope levels. Double immunofluorescence with neuronal or astrocytic markers confirmed the neuronal and astrocytic location of fructose‐1,6‐bisphosphatase in confocal microscope images. At the subcellular level, fructose‐1,6‐bisphosphatase was located in the nuclear and cytoplasmic compartments of both neurons and astrocytes, at all ages studied. Ultrastructurally, immunostaining appeared as small patches in the nucleus and the cytosol. In addition, immunostaining was present over the outer mitochondrial membrane, the plasma membrane, and the membranes of the rough endoplasmic reticulum and nuclear envelope, but not over Golgi membranes. In the neuropil fructose‐1,6‐bisphosphatase was located in dendritic spines, as well as in abundant astrocytic processes that, in some cases, surrounded immunopositive synapses. The possible role of fructose‐1,6‐bisphosphatase in neurons and astrocytes is discussed. Microsc. Res. Tech., 2011. © 2010 Wiley‐Liss, Inc.     

Macrophages Compensate for Loss of Protein Tyrosine Phosphatase N2 in Dendritic Cells to Protect from Elevated Colitis

Protein tyrosine phosphatase nonreceptor type 2 (PTPN2) plays a critical role in the pathogenesis of inflammatory bowel diseases (IBD). Mice lacking PTPN2 in dendritic cells (DCs) develop skin and liver inflammation by the age of 22 weeks due to a generalized loss of tolerance leading to uncontrolled immune responses. The effect of DC-specific PTPN2 loss on intestinal health, however, is unknown. The aim of this study was to investigate the DC-specific role of PTPN2 in the intestine during colitis development. PTPN2^fl/flxCD11c^Cre mice were subjected to acute and chronic DSS colitis as well as T cell transfer colitis. Lamina propria immune cell populations were analyzed using flow cytometry. DC-specific PTPN2 deletion promoted infiltration of B and T lymphocytes, macrophages, and DCs into the lamina propria of unchallenged mice and elevated Th1 abundance during acute DSS colitis, suggesting an important role for PTPN2 in DCs in maintaining intestinal immune cell homeostasis. Surprisingly, those immune cell alterations did not translate into increased colitis susceptibility in acute and chronic DSS-induced colitis or T cell transfer colitis models. However, macrophage depletion by clodronate caused enhanced colitis severity in mice with a DC-specific loss of PTPN2. Loss of PTPN2 in DCs affects the composition of lamina propria lymphocytes, resulting in increased infiltration of innate and adaptive immune cells. However, this did not result in an elevated colitis phenotype, likely because increased infiltration of macrophages in the intestine upon loss of PTPN2 loss in DCs can compensate for the inflammatory effect of PTPN2-deficient DCs.