miR-146a通过TLR4/NF-κB通路调节小胶质细胞/巨噬细胞极化对缺血性脑卒中的保护作用

目的 探讨微小RNA-146a(MicroRNA-146a, miR-146a)在缺血性脑卒中小胶质细胞/巨噬细胞极化中的作用及其潜在机制。方法 构建大脑中动脉闭塞(Middle cerebral artery occlusion, MCAO)模型,脑内注射阴性对照物(Negative control mimic, NC mimic)或miR-146a mimic;构建BV2小鼠小胶质细胞(BV2 mouse microglia, BV2)缺血缺氧(Oxygen glucose deprivation, OGD)模型,将NC mimic, miR-146a mimic转染至OGD处理的BV2细胞中,进行改良神经功能缺损评分(Modified neurological severity scores, mNSS)评估神经功能;2,3,5-氯化三苯基四氮唑(2,3,5-Triphenyltetrazolium chloride, TTC)染色检测脑梗死体积;实时荧光定量聚合酶链反应(Real time quantification polymerase chain reaction, RT...     

钴铬、镍铬、含钛镍铬烤瓷合金在人工唾液中耐腐蚀性能的比较

目的:评价钴铬、镍铬、含钛镍铬烤瓷合金在人工唾液中的耐腐蚀性能。方法:采用动电位极化曲线法测定钴铬、镍铬、含钛镍铬烤瓷合金试件的自腐蚀电流密度、极化电阻、自腐蚀电位,并得出3种合金的极化曲线。应用场发射扫描电子显微镜(FSEM),观察实验前、后试件表面的形貌变化。采用SPSS11.0软件包对数据进行单因素方差分析。结果:钴铬合金试件自腐蚀电流密度显著低于镍铬合金(P<0.05)及含钛镍铬合金(P<0.05);含钛镍铬合金试件自腐蚀电流密度低于镍铬合金(P<0.05)。钴铬合金试件的极化电阻显著高于镍铬合金(P<0.05)及含钛镍铬合金(P<0.05);含钛镍铬合金试件的极化电阻明显高于镍铬合金(P<0.05)。钴铬合金试件的自腐蚀电位高于镍铬合金(P<0.05)及含钛镍铬合金(P>0.05);含钛镍铬合金试件的自腐蚀电位高于镍铬合金(P>0.05)。FSEM显示,钴铬合金试样表面腐蚀较镍铬合金及含钛镍铬合金轻微。结论:钴铬烤瓷合金的耐腐蚀性优于镍铬烤瓷合金及含钛镍铬烤瓷合金,含钛镍铬烤瓷合金耐腐蚀性不及镍铬烤瓷合金。     

Effect of the methylenetetrahydrofolate reductase gene polymorphisms on homocysteine, folate and vitamin B12 in patients with bipolar disorder and relatives

We investigated the effect of polymorphic variants of c.1298A>C (Glu429Ala) and c.677C>T (Ala222Val) in methylenetetrahydrofolate (MTHFR) gene on the total homocysteine (tHcy), folate and B12 levels in patients with bipolar disorder, first-degree relatives of patients, and controls. The c.677C>T and c.1298A>C polymorphisms in MTHFR were determined by polymerase chain reaction-restriction fragment length polymorphism in 197 bipolar patients, 278 relatives and 238 controls. tHcy and folate and vitamin B12 levels were measured by Fluorescence Polarization Immunoassay and Electrochemiluminescence, respectively. The tHcy was significantly increased in patients and relatives. In contrast, folate and B12 were significantly lower in patients and relatives. Gender was not considered as a significant determinant in the multivariate analysis. Genotypes of c.1298A>C and c.677C>T were correlated with tHcy, folate and B12. Patients and relatives carrying TT and/or AA and AC genotypes had elevated tHcy and reduced folate and B12 levels. High tHcy but low folate and vitamin B12 levels may be a risk factor for development of bipolar disorder.     

Neuroprotective modulation of microglia effector functions following priming with interleukin 4 and 13: current limitations in understanding their mode-of-action

In recent years the long-standing theory of microglia’s properties for dual polarization towards a pro- or anti-inflammatory phenotype has been deeply challenged. Furthermore, the elucidation of microglia ontogenesis exposed intrinsic differences between microglia and peripheral myeloid cells, thereby further underscoring the need to re-evaluate microglia-specific activation behavior, especially within an inflamed central nervous system (CNS) environment. This review critically summarizes recent literature on the in vitro and in vivo response of murine microglia to the immune-modulatory cytokines interleukin 4 (IL4) and interleukin 13 (IL13), i.e. those driving the so-called anti-inflammatory phenotype. Here we highlight several pivotal factors that may influence experimental outcome and/or interpretation of in vitro and in vivo studies evaluating microglia’s phenotypical and functional properties upon IL4/IL13 treatment. Finally, the current therapeutic relevance of IL4/IL13-induced microglia activation in both acute and chronic CNS disorders is discussed.     

Role of Rho-ROCK signaling in MOLT4 cells metastasis induced by CCL25

Our previous research has revealed that binding of the chemokine CCL25 to the CCR9 provides chemotactic cues guiding leukemic cells to specific tissues and organs. The RhoA-ROCK pathway might be involved in cancer migration. The purpose of this study was to explore the role of the RhoA-ROCK-MLC axis in leukemic cell migration following exposure to CCL25. The results showed that CCL25 could increase the amount of the GTPase RhoA and activate MLC in MOLT4 cells in a time-dependent manner. C3 exoenzyme and Y-27632 could block MOLT4 cell migration and chemotaxis. Thus, the RhoA-ROCK-MLC axis might play an important role in MOLT4 cell metastasis induced by CCL25.     

No evidence for behavioral responses to circularly polarized light in four scarab beetle species with circularly polarizing exocuticle

The strongest known circular polarization of biotic origin is the left-circularly polarized (LCP) light reflected from the metallic shiny exocuticle of certain beetles of the family Scarabaeidae. This phenomenon has been discovered by Michelson in 1911. Although since 1955 it has been known that the human eye perceives a visual illusion when stimulated by circularly polarized (CP) light, it was discovered only recently that a stomatopod shrimp is able to perceive circular polarization. It is pertinent to suppose that scarab beetles reflecting LCP light in an optical environment (vegetation) being deficient in CP signals may also perceive circular polarization and use it to find each other (mate/conspecifics) as until now it has been believed. We tested this hypothesis in six choice experiments with several hundred individuals of four scarab species: Anomala dubia, Anomala vitis (Coleoptera, Scarabaeidae, Rutelinae), and Cetonia aurata, Potosia cuprea (Coleoptera, Scarabaeidae, Cetoniinae), all possessing left-circularly polarizing exocuticle. From the results of our experiments we conclude that the studied four scarab species are not attracted to CP light when feeding or looking for mate or conspecifics. We demonstrated that the light reflected by host plants of the investigated scarabs is circularly unpolarized. Our results finally solve a puzzle raised over one hundred years ago, when Michaelson discovered that scarab beetles reflect circularly polarized light.     

Macrophage regulation of graft-vs-host disease

Hematopoietic stem cell transplantation has become a curative choice of many hematopoietic malignancy, but graft-vs-host disease (GVHD) has limited the survival quality and overall survival of hematopoietic stem cell transplantation. Understanding of the immune cells’ reaction in pathophysiology of GVHD has improved, but a review on the role of macrophages in GVHD is still absent. Studies have observed that macrophage infiltration is associated with GVHD occurrence and development. In this review, we summarize and analyze the role of macrophages in GVHD based on pathophysiology of acute and chronic GVHD, focusing on the macrophage recruitment and infiltration, macrophage polarization, macrophage secretion, and especially interaction of macrophages with other immune cells. We could conclude that macrophage recruitment and infiltration contribute to both acute and chronic GVHD. Based on distinguishing pathology of acute and chronic GVHD, macrophages tend to show a higher M1/M2 ratio in acute GVHD and a lower M1/M2 ratio in chronic GVHD. However, the influence of dominant cytokines in GVHD is controversial and inconsistent with macrophage polarization. In addition, interaction of macrophages with alloreactive T cells plays an important role in acute GVHD. Meanwhile, the interaction among macrophages, B cells, fibroblasts, and CD4+ T cells participates in chronic GVHD development.     

间充质干细胞生物学特性的研究进展*

【摘要】 间充质干细胞(mesenchymal stem cells, MSCs)是一种具有自我复制和多向分化潜能的成体干细胞,在体内或体外特定的诱导条件下,能够分化成骨、软骨、脂肪、内皮等多种细胞。MSCs具有低免疫原性,同时还具有强大的免疫调节作用。基于MSCs的生物学特性的多样性,目前对MSCs的研究涉及到抗炎治疗、组织修复和再生、移植物抗宿主病（GVHD）、自身免疫性疾病等多个方面,具有广泛的临床应用前景。本文对MSCs的生物学特性的研究进展作一综述。