Mechanism and Application of α7 nAChR in Cholinergic Antiinflammatory Pathway / 中国生物化学与分子生物学报

Cholinergic anti-inflammatory pathway in which acetylcholine released as the neurotransmitter, plays an important role in nerve-immune regulation. In this pathway, with the vagus nerve in the central nervous system as a starting point, the alpha 7 nicotinic acetylcholine receptor (α7 nAChR) on the surface of immune cell membrane is the key functional part. The interaction between electrical and chemical signals regulates the inflammation in the body via modulation of the JAK-STAT3, PI3K-Akt and other signaling pathways and the nuclear translocation of NF-κB, leading to inhibition of the release of pro-inflammatory factors and promotion of the release of anti-inflammatory factors. However, the detailed mechanism is far from clear. Studies have shown that the cholinergic anti-inflammatory pathway can be activated by drug targeting α7 nAChR and electrical stimulation of vagus nerve. Activation of α7 nAChR has the advantages of simple operation, less damage and significant effect. The commonly used drugs are selective agonists such as PNU282987 and GTS-21, and non-selective agonists such as nicotine. And this method has been found to play a role in the treatment of peripheral organ inflammatory diseases such as sepsis, ischemia-reperfusion injury, gastroenteritis, osteoarthritis and autoimmune diseases. As a key factor in the cholinergic anti-inflammatory pathways, α7 nAChR has become a potential therapeutic target for many inflammatory diseases. This paper reviewed the anti-inflammatory mechanism and activation mode of α7 nAChR involved in cholinergic anti-inflammatory pathway, as well as its application in inflammatory diseases in recent years, which may provide a reference for future research on its detailed mechanism of action and potential application as a new therapeutic target.

Effect of Huanglian Jiedutang on Learning and Memory Ability and Cholinergic System in AD Rats Induced by Aβ1-42 / 中国实验方剂学杂志

Objective:To investigate the effects of Huanglian Jiedutang on learning and memory ability and the cholinergic system in Alzheimer's disease（AD） rats induced by amyloid <italic>β</italic>-protein（A<italic>β</italic>）_1-42. Method:Sixty male SD rats were divided into normal group， model group， huperzine A group （2.1×10^-5 g·kg^-1）， high-， medium- and low dose of Huanglian Jiedutang groups （6，3，1.5 g·kg^-1）. AD rat model was replicated by hippocampal injection of A<italic>β</italic>_1-42. After 4 weeks of treatment， Morris water maze test was performed. Hematoxylineosin （HE） staining was used to observe the pathological changes of rat hippocampus. Sampling blood from abdominal aorta was taken. Acetylcholine （ACh）， acetylcholinesterase （AchE） and choline acetyltransferase （ChAT） in serum and hippocampus were detected by enzyme-linked immunosorbent assay （ELISA）. The expression of hippocampal <italic>α</italic>7 nicotinic acetylcholine receptor （<italic>α</italic>7nAChR） protein was detected by Western blot. The expression of hippocampal <italic>α</italic>7nAChR mRNA was detected by Real-time fluorescence quantitative polymerase chain reaction （Real-time PCR）. Result:Compared with the normal group， there were obvious pathological changes in the model group，such as neuron necrosis in the cerebral cortex，pyramidal cell or granular cell necrosis in the hippocampus，disorder of arrangement and inflammatory cell infiltration，prolonged escape latency，decreased escape platform times，decreased residence time in the effective area and swimming path in the effective area （<italic>P<</italic>0.05，<italic>P<</italic>0.01）. The contents of <italic>α</italic>7nAChR mRNA，ACh，AchE，ChAT，<italic>α</italic>7nAChR in the hippocampus decreased （<italic>P<</italic>0.01）. Compared with the model group，the escape latency of the middle dose group was shorter （<italic>P<</italic>0.05）， the escape platform times，the swimming path in the effective area and the residence time in the effective area increased （<italic>P<</italic>0.05，<italic>P<</italic>0.01）， the contents of serum ACh，ChAT， hippocampal AchE，ChAT and <italic>α</italic>7nAChR increased （<italic>P<</italic>0.05，）. The expression of hippocampal <italic>α</italic>7nAChR protein significantly increased （<italic>P<</italic>0.01）， the residence time of effective area in high dose group was prolonged （<italic>P<</italic>0.01）， the times of escape platform increased，and the contents of serum ACh，ChAT and hippocampal ACh，AchE，<italic>α</italic>7nAChR protein and <italic>α</italic>7nAChR mRNA increased （<italic>P<</italic>0.05）. Conclusion:Huanglian Jiedutang can significantly improve the learning and memory ability of AD rats induced by A<italic>β</italic>_1-42，and its mechanism may be related to the improvement of cholinergic system damage and enhancement of cholinergic system function induced by A<italic>β</italic>_1-42.

Toxicity and Efficacy of Water-eluted Fraction from Siegesbeckiae Herba Against Human Embryonic Lung Fibroblasts / 中国实验方剂学杂志

Objective:To detect the toxicity of water-eluted fraction from Siegesbeckiae Herba （SWEF） at different concentrations against MRC-5 human embryonic lung fibroblasts and its impacts on the expression of <italic>α</italic>7 nicotinic acetylcholine receptor （<italic>α</italic>7nAChR） and inflammatory factors， so as to figure out the active components responsible for toxicity and efficacy. Method:The toxicities of SWEF at 1， 6， 10， 20， and 50 g·L^-1 against MRC-5 cells were determined by cell counting kit-8 （CCK-8） assay combined with flow cytometry and Trypan blue staining. The changes in <italic>α</italic>7nAChR expression and inflammatory factor levels before and after <italic>α</italic>7nAChR gene silencing were detected to reveal the pharmacodynamic effect of SWEF on MRC-5 cells. Result:SWEF （≥6 g·L^-1） obviously inhibited the viability of MRC-5 cells （<italic>P</italic><0.01） and promoted their apoptosis and necrosis （<italic>P</italic><0.01）， with the half-maximal inhibitory concentration （IC₅₀） being 6.03 g·L^-1. The determination of <italic>α</italic>7nAChR expression and inflammatory factor levels in MRC-5 cells showed that SWEF contained <italic>α</italic>7nAChR agonist-like substance， which enhanced <italic>α</italic>7nAChR mRNA and protein expression （<italic>P</italic><0.05， <italic>P</italic><0.01） and decreased the inflammatory factor levels （<italic>P</italic><0.05， <italic>P</italic><0.01）. SWEF down-regulated the inflammatory factors possibly by re-regulating <italic>α</italic>7nAChR mRNA expression， exhibiting a negative correlation between them （<italic>P</italic><0.01）. Conclusion:SWEF （≥6 g·L^-1） is highly toxic to MRC-5 cells. Pharmacodynamic studies have confirmed that <italic>α</italic>7nAChR agonist-like substance contained in SWEF was responsible for the elevated <italic>α</italic>7nAChR expression and reduced inflammatory cytokines. It is inferred that excessive <italic>α</italic>7nAChR agonist-like substance may trigger the toxicity of<italic> </italic>Siegesbeckiae Herba.

Construction of the brain-targeting drug carrier through imprinting of nicotinic acetylcholine receptor α7 / 药学学报

In this study, a novel brain-targeting carrier was made via conformational epitope imprinting. Acrylamide and N,N'-methylene bisacrylamide was used as carrier materials and the N-terminal epitope of nicotinic acetylcholine receptor α7 (nAchR α7) was tested as a template molecule, and the polymer nanoparticles were obtained after polymerization and template removal. The nanoparticles were investigated by particle size analyzer and transmission electron microscopy (TEM). Their targeting capabilities were investigated with a cell uptake assay in vitro and fluorescence imaging in vivo. The results suggest that the nanoparticles had a small particle size (42.1±4.3 nm) with a homogeneous distribution, and good targeting properties in vitro and in vivo. We have made the molecularly imprinted polymer nanoparticles with brain targeting capability, which represents a new tool in the treatment of brain diseases.

Changes of nicotinic acetylcholine receptor α7 expression in CD4 + CD25+ T lymphocytes of children with sepsis / 中华实用儿科临床杂志

Objective To study the expression of nicotinic acetylcholine receptor α7 in CD4 + CD25 + T lymphocytes of peripheral blood in children with sepsis,and to analyze the role of α7nAChR in the development of sepsis.Methods Forty-nine hospitalized patients with sepsis from Nov.2011 to Dec.2012 in PICU of Nanjing Children's Hospital Affiliated to Nanjing Medical University were enrolled,and they were divided into the survival group (n =33)and the dead group (n =16) in accordance with the outcome.At the same time,the total of 40 cases including the children receiving inguinal hernia repair and the children receiving health examination were enrolled as control group.Peripheral venous blood was collected to detect the expression of CD4 +/CD25 +/α7nAChR by indirect flow cytometry.Simultaneously,the CD3 +,CD4 +,CD8 +,CD4 +/CD8 + ratio were detected,and Acute Physiology and Chronic Health Evaluation Ⅱ (APACHE Ⅱ) scores were calculated.Results The expressions of CD4 +/CD25 +/α7nAChR in sepsis group were much lower than those in the control group [(25.8 ± 3.1) ％ vs (34.9 ± 2.9) ％,P ＜ 0.05] ; and the expression of CD4 + CD25 +/α7nAChR in the dead group was also significantly lower than that in the survival group [(22.4 ± 2.5) ％ vs (28.1 ± 2.9) ％,P ＜ 0.05].The expressions of α7nAChR on CD4 +/CD25 + T lymphocytes of peripheral blood in children with sepsis was negatively correlated with the APACHE Ⅱ score (r =-0.512,P ＜ 0.05).The CD3 +,CD4 +,CD4 +/CD8 + ratios in the dead group were significantly lower than those in the control group (all P ＜ 0.05) ; in the survival group and the control group,the values of CD3 +,CD4 +,CD8 + were not significantly different,while the ratios of CD4 +/CD8 + between these 2 groups had a significant difference(P ＜ 0.05).Conclusions The expressions of α7nAChR on the CD4 + CD25 +T lymphocytes in the children with sepsis were reduced,and the expressions were lower,the outcome were worse;the children with sepsis have cell immune dysfunction.