Cognitive effects of the GSK-3 inhibitor “lithium” in LPS/chronic mild stress rat model of depression: Hippocampal and cortical neuroinflammation and tauopathy

Low-dose repeated lipopolysaccharide pre-challenge followed by chronic mild stress (LPS/CMS) protocol has been introduced as a rodent model of depression combining the roles of immune activation and chronic psychological stress. However, the impact of this paradigm on cognitive functioning has not been investigated hitherto.MethodsThis study evaluated LPS/CMS-induced cognitive effects and the role of glycogen synthase kinase-3β (GSK-3β) activation with subsequent neuroinflammation and pathological tau deposition in the pathogenesis of these effects using lithium (Li) as a tool for GSK-3 inhibition.ResultsLPS pre-challenge reduced CMS-induced neuroinflammation, depressive-like behavior and cognitive inflexibility. It also improved spatial learning but increased GSK-3β expression and exaggerated hyperphosphorylated tau accumulation in hippocampus and prefrontal cortex. Li ameliorated CMS and LPS/CMS-induced depressive and cognitive deficits, reduced GSK-3β over-expression and tau hyperphosphorylation, impeded neuroinflammation and enhanced neuronal survival.ConclusionThis study draws attention to LPS/CMS-triggered cognitive changes and highlights how prior low-dose immune challenge could develop an adaptive capacity to buffer inflammatory damage and maintain the cognitive abilities necessary to withstand threats. This work also underscores the favorable effect of Li (as a GSK-3β inhibitor) in impeding exaggerated tauopathy and neuroinflammation, rescuing neuronal survival and preserving cognitive functions. Yet, further in-depth studies utilizing different low-dose LPS challenge schedules are needed to elucidate the complex interactions between immune activation and chronic stress exposure.     

Poly(Ethyleneimine)‐Immobilized‐Cloth Enzyme Immunoassay for the Detection of Salmonella Lipopolysaccharide

Poly(ethyleneimine) (PEI) was immobilized on non‐woven polyester cloth and examined for application on a simple, rapid and economical “cloth enzyme immunoassay (CEIA)” which was developed originally as polymyxin‐CEIA for the detection of Salmonella lipopolysaccharide (LPS). PEI‐cloth regardless of the PEI molecular weight, but with the amine group contents of 0.1 ～ 0.35 meq/g immobilized either in a physisorption‐like or chemisorption‐like manner, adsorbed LPS rapidly, preferentially and effectively. The captured LPS was then able to be detected qualitatively and quantitatively as an antigen by enzyme immunoassay. PEI‐CEIA had a detection limit for Salmonella LPS of 10 ng/ml, which was equivalent to 1.6 × 10⁵ cell/ml and was ten times more sensitive than polymyxin‐CEIA. It was possible to detect Salmonella LPS in the presence of a 100‐fold excess of E. coli LPS. PEI‐CEIA was found to be more sensitive and much easier to carry out than polymyxin‐CEIA but had the same advantages as polymyxin‐CEIA.     

In utero immune programming of autism spectrum disorder (ASD)

Maladaptation of immune tolerance at the maternal-fetal interface affects balanced maternal-fetal cross-talk and placental health and is associated with adverse pregnancy outcomes. The concept of in utero programming of childhood and adulthood diseases has revolutionized the research on the role of pregnancy in maternal, neonatal, and adult health. However, it is not yet well understood whether dysregulation of uterine immunity contributes to any health consequences during childhood or later in life. Recent observations in mice and humans have strongly supported the notion that uterine immunity during pregnancy determines the health trajectory of the offspring and significantly impacts cognitive function and mental health. Importantly, IL-17a producing Th17 T cells have been projected as the main contributors to heterogeneous pathological and behavioral phenotypes associated with autism spectrum disorder (ASD). However, since normal pregnancy is associated with little or no Th17 cells at the maternal-fetal interface, it is not clear how and when the Th17 T cells are generated and which interventions can ameliorate the ASD-like features in newborns. We propose that infection-associated uterine immune activation within a critical window of development may propel trans-differentiation of Th17 T cells that eventually affect fetal brain development and induce ASD-like behavioral phenotype in the offspring.     

KLF4在LPS诱导的心肌细胞损伤中的作用研究

背景:KLF4作为一种转录因子在保持血管内皮功能中发挥重要作用,然而其是否能够保护心肌细胞免受脂多糖诱导的损伤尚不清楚。目的探讨KLF4在脂多糖诱导的心肌细胞损伤中的作用。方法:分离培养原代大鼠乳鼠心肌细胞,将其随机（随机数字法）分为5组：空白组,阴性对照组（NC组）,NC+脂多糖刺激组（NC+LPS组）,KLF4过表达组,KLF4过表达+LPS组。采用MTT法检测细胞活性,采用试剂盒检测细胞活性氧（ROS）,超氧化物歧化酶（SOD2）,谷胱甘肽过氧化物酶（Gpx）和丙二醛（MDA）的水平;采用酶联免疫吸附法（Elisa）检测细胞中肿瘤坏死因子（TNFa）,白细胞介素-1β（IL-1β）和IL-6的水平。采用Tunel染色检测细胞凋亡。采用免疫印迹检测TLR4和核因子E2相关因子2（NRF2）的蛋白水平。结果:心肌细胞转染KLF4过表达腺病毒后,细胞中KLF4的表达明显高于NC组（ P<0.05）。NC+LPS组细胞活性明显低于NC组（ P<0.05）,KLF4过表达+LPS组细胞活性高于NC+LPS组（ P<0.05）。与对照组相比,NC+LPS组中的心肌细胞TNFα、IL-1β、IL-6蛋白表达水平明显升高（ P<0.0001）,KLF4过表达+LPS组心肌细胞TNFα、IL-1β、IL-6蛋白表达水平则显著降低（ P<0.0001）。NC+LPS组心肌细胞ROS和MDA水平明显高于NC组,而SOD2和Gpx的活性低于NC组（ P<0.0001）;KLF4过表达+LPS组心肌细胞ROS和MDA水平的水平明显降低,而SOD2和Gpx的活性明显升高（ P<0.0001）。LPS组心肌细胞凋亡数量明显高于NC组,KLF4过表达+LPS组心肌细胞凋亡数量明显降低（ P<0.001）。LPS组心肌细胞TLR4总蛋白水平高于NC组,NRF2的核蛋白水平低于NC组;KLF4过表达+LPS组心肌细胞TLR4的总蛋白水平降低,NRF2的核蛋白水平显著增高（ P<0.001）。 结论：:KLF4可抑制LPS诱导的心肌细胞损伤,其作用机制可能是通过抑制LPS诱导的心肌细胞中TLR4的表达,促进NRF2向细胞核转移来抑制炎症因子释放,减轻氧化应激损伤及抑制细胞凋亡。     

五味子乙素对脂多糖诱导的脓毒症急性肺损伤大鼠肺组织病理损伤、炎症反应和核因子-κB表达的影响

目的 观察五味子乙素对脂多糖（lipopolysaccharide,LPS）诱导的脓毒症急性肺损伤大鼠肺组织病理损伤、炎症反应和核因子 -κB （nuclear factor kappa-B,NF-κB）表达的影响。方法 采用气管滴注40 mg/kg LPS制备大鼠急性肺损伤大鼠模型,手术前1 h腹腔注射80 mg/kg 五味子乙素进行干预治疗,测定大鼠肺湿/干质量比,BCA试剂盒测定大鼠支气管肺泡灌洗液（bronchoalceolar lavage fluid,BALF）总蛋白,牛鲍氏计数板计算 BALF中白细胞数,苏木精-伊红染色观察大鼠肺组织损伤情况,ELISA法检测大鼠肺组织中肿瘤坏死因子-α（tumor necrosis factor-α,TNF-α）、白细胞介素-1β（interleukin-1β,IL-1β）、白细胞介素-6（interleukin-6,IL-6）含量,相关试剂盒检测大鼠肺组织中丙二醛（malondialdehyde,MDA）和超氧化物歧化酶（superoxide dismutase,SOD）含量,蛋白质印迹法检测大鼠肺组织中NF-κB p65、磷酸核因子- κB 抑制蛋白（phosphorylation inhibitor of nuclear factor kappa-B,pIκBα）和Toll样受体4（Toll-like receptor 4,TLR4）的表达水平。结果 与模型组相比,五味子乙素组大鼠肺湿/干质量比、BALF中总蛋白含量及白细胞数均显著减少（P<0.05）,病理损伤显著减轻,TNF-α、IL-1β、IL-6含量均显著减少（P<0.05）,MDA含量显著下降,SOD活性显著升高（P<0.05）,NF-κB p65、pIκBα和TLR4表达水平均显著下调（P<0.05）。结论 五味子乙素能够减轻LPS诱导的脓毒症急性肺损伤大鼠肺组织的病理损伤,抑制炎症反应和氧化应激反应,抑制NF-κB通路激活。     

不同低密度脂蛋白氧化模型中维生素E的抗氧化效率差异

目的　探讨维生素E（VE）在不同低密度脂蛋白（LDL）氧化模型中抗氧化效率的差异,并揭示VE在体外抗氧化效率不高的可能原因。方法　分别建立LDL主动氧化模型和被动氧化模型,观察LDL与VE共刺激0、12　h以及脂多糖（LPS）与VE共刺激0、3　h后细胞内人α防御素（HNP-1）蛋白及其mRNA水平的表达变化,再通过检测羟基化蛋白（PCO）、丙二醛（MDA）来判断VE是否干扰模型的建立。再将两种氧化模型分别设立氧化模型建立前、后加入VE以及VE（－）组,最后检测不同时间点加入VE后MDA、PCO的变化以分析VE在不同模型中的抗氧化效率差异,并观察细胞内氧自由基水平的波动以判断差异产生的可能原因。　结果　（1）氧化模型中HNP-1mRNA及其蛋白水平的表达均升高,MDA和PCO的生成量也显著升高（P<0.05）。（2）主动氧化模型中不同时间点加入VE后PCO生成量无明显差异（P>0.05）;被动氧化前加VE组氧化产物生成量明显低于被动氧化后加VE组（P<0.05）。不同氧化模型的MDA、PCO生成量在氧化前加VE组和氧化后加VE组降低,且被动氧化模型中下降幅度更加明显,而VE（－）组含量变化趋势相同。（3）不同氧化模型中加入VE,均能够显著提高超氧化物歧化酶（SOD）活性;能够降低自由基水平,且在被动氧化前加VE组自由基水平降低更明显（P>0.05）。　结论　VE的抗氧化效率在被动氧化模型中优于主动氧化模型,与VE的加入时间、胞内自由基水平相关。     

CD8~+ T细胞在早期内毒素血症对心功能的损害作用

目的:探讨CD8+T细胞在早期内毒素血症心脏损伤中的浸润及其对心功能的影响。方法:野生雄性小鼠20只随机分为野生对照组和野生内毒素血症组,每组各10只;CD8敲除雄性小鼠10只,随机分为CD8敲除对照组和CD8敲除内毒素血症组,每组各5只。对照组均给予0.9%氯化钠液腹腔注射,内毒素血症组均给予脂多糖腹腔注射。6 h显微超声检测射血分数及短轴缩短分数;即刻处死并收取野生对照组及野生内毒素血症组各3只小鼠心脏组织,流式细胞技术检测心脏细胞悬液中巨噬细胞(F4/80+细胞)及CD8+T细胞、CD4+T细胞分布;其余小鼠心脏组织进行病理切片HE染色,观察心肌纤维断裂及炎症细胞浸润。结果:与野生对照组相比,野生内毒素血症组射血分数及短轴缩短分数显著降低(均为P<0.05);野生内毒素血症组F4/80+细胞、CD4+T细胞及CD8+T细胞均显著增加(均为P<0.05)。与野生内毒素血症组相比,CD8基因敲除内毒素血症组射血分数及短轴缩短分数均显著升高(均为P<0.05)。结论:急性内毒素血症导致心肌纤维损伤、心功能不全,心脏组织CD8+T等炎症细胞浸润;而缺乏CD8+T细胞时则减轻内毒素血症导致的心功能损伤,提示CD8+T细胞在急性内毒素血症诱导的心功能不全早期发挥重要作用。