Inhibition of homodimerization of Toll-like receptor 4 by curcumin

Toll-like receptors play a key role in sensing microbial components and inducing innate immune responses. Ligand-induced dimerization of TLR4 is required for the activation of downstream signaling pathways. Thus, the receptor dimerization may be one of the first lines of regulation in activating TLR-mediated signaling pathways and induction of subsequent immune responses. LPS induces the activation of NF-kappaB and IRF3 through MyD88- or TRIF-dependent pathways. Curcumin, a polyphenol found in the plant Curcuma longa, has been shown to suppress the activation of NF-kappaB induced by various pro-inflammatory stimuli by inhibiting IKKbeta kinase activity in MyD88-dependent pathway. Curcumin also inhibited LPS-induced IRF3 activation. These results imply that curcumin inhibits both MyD88- and TRIF-dependent pathways in LPS-induced TLR4 signaling. However, in TRIF-dependent pathway, curcumin did not inhibit IRF3 activation induced by overexpression of TRIF in 293T cells. These results suggest that TLR4 receptor complex is the molecular target of curcumin in addition to IKKbeta. Here, we report biochemical evidence that phytochemicals (curcumin and sesquiterpene lactone) inhibit both ligand-induced and ligand-independent dimerization of TLR4. Furthermore, these results demonstrate that small molecules with non-microbial origin can directly inhibit TLRs-mediated signaling pathways at the receptor level. These results imply that the activation of TLRs and subsequent immune/inflammatory responses induced by endogenous molecules or chronic infection can be modulated by certain dietary phytochemicals we consume daily.     

异氟烷对幼小鼠自主活动和学习记忆行为的影响

目的观察异氟烷(Iso)对幼小鼠自主活动和学习记忆行为的影响,探讨其与γ-氨基丁酸A受体(GABAA)的关系。方法 360只小鼠分为3大组,分别进行自主活动实验、避暗实验和跳台实验,每大组按分层随机区组设计分为正常对照组,Iso 0.05,0.1和0.2 ml·kg-1组、GABAA受体特异性阻断剂一叶萩碱(Sec)2,4和8 mg.kg-1组和Iso 0.2 m.lkg-1+Sec 2,4和8 mg.kg-1组。小鼠sc给予Sec 10 min后,再ip给予Iso,测试给药后15,30,45和60 min小鼠5 min内活动次数;跳台仪和避暗仪记录小鼠步入、跳下的潜伏期和错误次数。结果与同一时间点的正常对照组相比,Iso可减少小鼠自主活动次数,给予Iso后1 d小鼠避暗实验和跳台实验的步入和跳下潜伏期缩短以及错误次数增加(P<0.05)。正常小鼠单独给Sec(除Sec 8 mg·kg-1组15 min外)对小鼠自主活动、步入和跳下潜伏期和错误次数无明显影响,但Sec可改善Iso导致的小鼠自主活动次数,拮抗Iso对小鼠自主活动的影响,但随着时间延长拮抗作用逐渐减弱,明显低于正常对照组(P<0.05)。Sec延长Iso小鼠的跳下和步入潜伏期,减少错误次数,基本恢复至正常对照组水平,明显改善Iso对幼小鼠学习记忆的影响(P<0.05)。结论 Iso可降低幼小鼠自主活动次数,损害学习记忆能力,GABAA受体可能部分参与了以上作用。     

Astrocytes in the damaged brain: Molecular and cellular insights into their reactive response and healing potential

Long considered merely a trophic and mechanical support to neurons, astrocytes have progressively taken the center stage as their ability to react to acute and chronic neurodegenerative situations became increasingly clear. Reactive astrogliosis starts when trigger molecules produced at the injury site drive astrocytes to leave their quiescent state and become activated. Distinctive morphological and biochemical features characterize this process (cell hypertrophy, upregulation of intermediate filaments, and increased cell proliferation). Moreover, reactive astrocytes migrate towards the injured area to constitute the glial scar, and release factors mediating the tissue inflammatory response and remodeling after lesion. A novel view of astrogliosis derives from the finding that subsets of reactive astrocytes can recapitulate stem cell/progenitor features after damage, fostering the concept of astroglia as a promising target for reparative therapies. But which biochemical/signaling pathways modulate astrogliosis with respect to both the time after injury and the type of damage? Are reactive astrocytes overall beneficial or detrimental for neuroprotection and tissue regeneration? This debate has been animating this research field for several years now, and an integrated view on the results obtained and the possible future perspectives is needed. With this Commentary article we have attempted to answer the above-mentioned questions by reviewing the current knowledge on the molecular mechanisms controlling and sustaining the reaction of astroglia to injury and its stem cell-like properties. Moreover, the cellular/molecular mechanisms supporting the detrimental or beneficial features of astrogliosis have been scrutinized to gain insights on possible pharmacological approaches to enhance astrocyte neuroprotective activities.     

γ-丁内酯类衍生物的合成及其脂肪酸合成酶抑制活性的研究

目的 以C75为先导化合物,设计、合成γ-丁内酯类衍生物,并研究其脂肪酸合成酶（fatty acid synthase, FAS）的抑制活性,以期发现新颖的FAS抑制剂。方法 以衣康酸酐为起始原料,经酯化、烃代、缩合/环合、水解4步反应合成目标化合物,采用体外方法初步筛选其FAS的抑制作用。结果与结论 合成了11个目标化合物,其结构经核磁和质谱确证;初步活性评价结果显示,含饱和烷烃侧链的化合物具有较好的FAS抑制活性,随侧链烷基的延长,其抑酶活性有增强的趋势。     

1-取代吡唑烷酮类抗惊构效关系的研究

1-正癸基吡唑烷-3-酮(Ⅱ结构式见表1)是欧洲专利报道的一种新型减肥剂。White等报道该化合物可通过血脑屏障,并对γ-氨基丁酸氨基转移酶(GABA-T)有强烈的抑制活性,但对谷氨酸脱羧酶的抑制作用较弱,因此可引起脑内γ-氨基丁酸(GABA)水平的升高,故我们相信应有抗惊活性。经我们合成后,发现Ⅱ确有良好的抗癲痫活性,抗小鼠最大电     

去甲斑蝥素对G422脑胶质瘤抑制作用的体内研究

目的:研究去甲斑蝥素(NCTD)体内对脑胶质瘤G422细胞的抑制作用。方法:建立G422细胞小鼠移植瘤模型,将荷瘤小鼠随机分为模型组、CTX阳性对照组及NCTD高、中、低剂量组(100、50、25 mg.kg-1),每组10只,另设10只为正常对照组,正常对照组每日给生理盐水灌胃,CTX和NCTD组采用腹腔注射方式给药,10 d后双抗体夹心ABC-ELISA法测sIL-2R的含量;酶联免疫ELISA法测IFN-γ含量;剥瘤,计算抑瘤率;剥瘤的同时取脾脏,计算脾脏指数;MTT法检测NCTD对荷瘤小鼠脾脏T、B淋巴细胞增殖的影响。结果:NCTD可降低荷瘤小鼠血清sIL-2R含量,提高IFN-γ含量,抑制G422细胞小鼠移植瘤的生长;对脾脏指数影响较少,可促进荷瘤小鼠的T、B淋巴细胞增殖。结论:NCTD体内外可抑制G422细胞生长,并具有免疫调节作用。     

呼吸道合胞病毒肺炎患儿急性期血清IFN-γ水平与病情相关性研究

目的观察呼吸道合胞病毒（RSV）肺炎患儿急性期血清中IFN-γ水平的变化和病情严重程度、过敏状态的关系,为临床上使用干扰素治疗重症RSV感染提供理论依据。方法实验组为RSV阳性的肺炎患儿42例;以患儿入院时的临床表现,将患儿分为轻度组和重度组其余为轻度,其中轻度组33例,重度组9例;根据患儿的过敏状况（如湿疹史）及家族过敏史（哮喘、过敏性鼻炎、过敏性结膜炎、特应性皮炎等）分为具有过敏因素组29例和无过敏因素组13例。对照组38例为年龄在2岁以内,同时期在医院外科住院,近1周内无呼吸道感染的患儿。用ELISA法检测血清中IFN-γ的浓度。结果实验组IFN-γ浓度与对照组比较,差异无统计学意义（P〉0.05）。实验组中轻度组IFN-γ浓度与重度组比较差异有统计学意义（P〈0.05）;而具有过敏因素组IFN-γ浓度与无过敏因素组比较差异无统计学意义（P〉0.05）。结论 RSV感染早期血清中IFN-γ的浓度与正常婴幼儿无明显差异;IFN-γ的水平与疾病的严重程度呈现明显的负相关,重度患儿IFN-γ浓度显著低于轻度患儿,对重度的RSV肺炎患儿,使用干扰素是合理的;RSV感染时IFN-γ的浓度与过敏因素之间未发现有显著的联系。     

海地瓜硫酸软骨素对3T3-L1前脂肪细胞增殖和分化的影响

目的研究海地瓜硫酸软骨素(Acaudina Molpadioideschondroitin sulfate,AM-CHS)对3T3-L1前脂肪细胞增殖和分化的影响,并探讨其作用机制。方法采用传统的鸡尾酒诱导剂诱导分化3T3-L1前脂肪细胞,以MTT法检测AM-CHS对3T3-L1前脂肪细胞及不同分化阶段3T3-L1细胞增殖活性的影响;分别采用油红O染色和甘油三酯(triglycerides,TG)含量测定法评价其对3T3-L1前脂肪细胞分化的影响。采用RT-PCR法检测脂肪细胞中过氧化物酶体增殖体激活受体γ(peroxisome proliferators-activated receptors gamma,PPARγ)、CCAAT增强子结合蛋白α(CCAAT/enhancer bind-ing protein alpha,C/EBPα)、固醇调节元件结合蛋白-1c(ste-rol regulatory element binding protein-1c,SREBP-1c)等分化相关基因的mRNA表达水平。结果 AM-CHS能明显抑制3T3-L1前脂肪细胞和成熟脂肪细胞的增殖,抑制3T3-L1前脂肪细胞的分化过程,以对分化早期的抑制作用最强。RT-PCR结果表明,AM-CHS能明显降低脂肪细胞PPARγ、C/EBPα和SREBP-1c mRNA的表达。结论海地瓜AM-CHS能明显抑制3T3-L1前脂肪细胞的增殖和分化,其作用机制与下调分化相关基因PPARγ、C/EBPα和SREBP-1c的表达有关。     

IFN‐α/β‐mediated NK2R expression is related to the malignancy of colon cancer cells

Neurokinin 2 receptor (NK2R), a G protein‐coupled receptor for neurokinin A (NKA), a tachykinin family member, regulates various physiological functions including pain response, relaxation of smooth muscle, dilation of blood vessels, and vascular permeability. However, the precise role and regulation of NK2R expression in cancer cells have not been fully elucidated. In this study, we found that high NK2R gene expression was correlated with the poor survival of colorectal cancer patients, and Interferon (IFN‐α/β) stimulation significantly enhanced NK2R gene expression level of colon cancer cells in a Janus kinas 1/2 (JAK 1/2)‐dependent manner. NKA stimulation augmented viability/proliferation and phosphorylation of Extracellular‐signal‐regulated kinase 1/2 (ERK1/2) levels of IFN‐α/β‐treated colon cancer cells and NK2R blockade by using a selective antagonist reduced the proliferation in vitro. Administration of an NK2R antagonist alone or combined with polyinosinic‐polycytidylic acid, a synthetic analog of double‐stranded RNA, to CT26‐bearing mice significantly suppressed tumorigenesis. NK2R‐overexpressing CT26 cells showed enhanced tumorigenesis and metastatic colonization in both lung and liver after the inoculation into mice. These findings indicate that IFN‐α/β‐mediated NK2R expression is related to the malignancy of colon cancer cells, suggesting that NK2R blockade may be a promising strategy for colon cancers.     

止咳平喘合剂对哮喘大鼠Th1/Th2细胞因子影响的实验研究

目的：观察中药复方止咳平喘合剂对哮喘大鼠Th1/Th2细胞因子的影响,从而进一步深化探讨名老中医经验方的作用机制。方法：随机将60只SD大鼠分为空白对照组、模型组、阳性对照组、止咳平喘合剂大、中、剂小剂量组,每组均为10只,以卵白蛋白（oval albumin,OVA）复制哮喘大鼠模型,采用ELISA方法检测血清中IL-4、IFN-γ含量,取右肺组织行HE染色进行形态学观察。结果：模型组血清中IL-4明显高于空白对照组（P〈0.01）,而IFN-γ明显低于空白对照组（P〈0.01）,存在IL-4/IFN-γ失衡;与模型组相比,阳性对照组、中药大剂量与中剂量组IL-4含量降低（P〈0.05）,而IFN-γ含量均有升高（P〈0.01～0.05）;并且血清IL-4与IFN-γ呈明显负相关（r为-0.974,P〈0.01）。结论：IFN-γ/IL-4的失衡参与哮喘发病过程,止咳平喘合剂可能通过下调IL-4的水平和提高IFN-γ的含量,纠正Th1/Th2细胞因子的失衡,进而减轻气道炎症。