EVs-mediated delivery of CB2 receptor agonist for Alzheimer’s disease therapy

Alzheimer’s disease(AD)is a typical neurodegenerative disease that leads to irreversible neuronal degeneration,and effective treatment remains elusive due to the unclear mechanism.We utilized biocompatible mesenchymal stem cell-derived extracellular vesicles as carriers loaded with the CB2 target medicine AM1241(EVs-AM1241)to protect against neurodegenerative progression and neuronal function in AD model mice.According to the results,EVs-AM1241 were successfully constructed and exhibited better bioavailability and therapeutic effects than bare AM1241.The Morris water maze(MWM)and fear conditioning tests revealed that the learning and memory of EVs-AM1241-treated model mice were significantly improved.In vivo electrophysiological recording of CA1 neurons indicated enhanced response to an auditory conditioned stimulus following fear learning.Immunostaining and Western blot analysis showed that amyloid plaque deposition and amyloidβ(Aβ)-induced neuronal apoptosis were significantly suppressed by EVs-AM1241.Moreover,EVs-AM1241 increased the number of neurons and restored the neuronal cytoskeleton,indicating that they enhanced neuronal regeneration.RNA sequencing revealed that EVs-AM1241 facilitated Aβphagocytosis,promoted neurogenesis and ultimately improved learning and memory through the calcium-Erk signaling pathway.Our study showed that EVs-AM1241 efficiently reversed neurodegenerative pathology and enhanced neurogenesis in modelmice,indicating that they are very promising particles for treating AD.

Central CB2 receptors in inflammation-driven neurodegeneration： dysregulation and therapeutic potential

In recent times there has been an intensification of interest in the pathological role of neuroinflammation in neurodegenerative disease. Neuroprotective strategies to slow, halt or reverse neuro- degeneration have not proven fruitful clinically, and the notion of a multi-hit hypothesis in the progression of neurodegenerative disease has steered focus towards other contributory pathological factors, particularly neuroinflammation. Neuroinflammation is believed to sustain the neurodegenerative pathology, forming a cy- clical and self-sustaining pathological process, with dying neurons activating microglia, which, once activated, can release several fac- tors that kill further neurons （reviewed in Blandini, 2013）.

大麻素受体2激动剂在谷氨酸氧化应激损伤中保护作用实验研究

目的:评价大麻素受体2(CB 2受体)通过抗氧化应激机制在谷氨酸对共培养小胶质细胞和神经元损伤中的保护作用。方法:采用随机数字表法将培养的N9小胶质细胞和HT22神经元分为四组(n=24):对照组(Con组)、谷氨酸组(Glu组)、CB 2受体激动剂AM1241+谷氨酸组(AM1241+Glu组)和AM1241+CB 2受体拮抗剂AM630+谷氨酸组(AM1241+AM630+Glu组)。Con组正常培养24 h;Glu组用含10 mmol/L谷氨酸的培养基孵育24 h;AM1241+Glu组用含2μmol/L AM1241和10 mmol/L谷氨酸的培养基孵育24 h;AM1241+AM630+Glu组含2μmol/L AM1241、6μmol/L AM630及10 mmol/L谷氨酸的培养基孵育24 h。采用MTT法测定细胞活力,采用化学比色法测定乳酸脱氢酶(LDH)、超氧化物歧化酶(SOD)活性及丙二醛(MDA)的含量。结果:与Con组比较,Glu组和AM1241+AM630+Glu组细胞活力和SOD活性降低,LDH活性和MDA含量升高(均P<0.05),AM1241+Glu组细胞活力和SOD活性降低,LDH含量升高(均P<0.05);与Glu组比较,AM1241+Glu组细胞活力和SOD活性升高,LDH活性和MDA含量降低(均P<0.05);与AM1241+Glu组比较,AM1241+AM630+Glu组细胞活力和SOD活性降低,LDH活性和MDA含量升高(均P<0.05)。结论:CB 2受体激活减轻谷氨酸诱发小胶质细胞和神经元损伤的机制与抗氧化作用有关。

Inhibition of 5-HT_3 Receptors-activated Currents by Cannabinoids in Rat Trigeminal Ganglion Neurons

This study investigated the modulatory effect of synthetic cannabinoids WIN55,212-2 on 5-HT3 receptor-activated currents (I5-HT3) in cultured rat trigeminal ganglion (TG) neurons using whole-cell patch clamp technique. The results showed that: (1) The majority of examined neurons (78.70%) were sensitive to 5-HT (3–300 μmol/L). 5-HT induced inward currents in a concentration-dependent manner and the currents were blocked by ICS 205-930 (1 μmol/L), a selective antagonist of the 5-HT3 receptor; (2) Pre-application of WIN55,212-2 (0.01–1 μmol/L) significantly inhibited I5-HT3 reversibly in concentration-dependent and voltage-independent manners. The concentra-tion-response curve of 5-HT3 receptor was shifted downward by WIN55,212-2 without any change of the threshold value. The EC50 values of two curves were very close (17.5±4.5) mmol/L vs. (15.2±4.5) mmol/L and WIN55,212-2 decreased the maximal amplitude of I5-HT3 by (48.65±4.15)%; (3) Neither AM281, a selective CB1 receptor antagonist, nor AM630, a selective CB2 receptor antagonist reversed the inhibition of I5-HT3 by WIN55,212-2; (4) When WIN55,212-2 was given from 15 to 120 s before 5-HT application, inhibitory effect was gradually increased and the maximal inhibition took place at 90 s, and the inhibition remained at the same level after 90 s. We are led to concluded that-WIN55,212-2 inhibited I5-HT3 significantly and neither CB1 receptor antagonist nor CB2 receptor antagonist could reverse the inhibition of I5-HT3 by WIN55,212-2. Moreover, WIN55,212-2 is not an open channel blocker (OCB) of 5-HT3 receptor. WIN55,212-2 significantly inhibited 5-HT-activated currents in a non-competitive manner. The inhibition of I5-HT3 by WIN55,212-2 is probably new one of peripheral analgesic mechanisms of WIN55,212-2, but the mechanism by which WIN55,212-2 inhibits I5-HT3 warrants further investigation.

大麻素CB1受体对大鼠视网膜神经节细胞诱发动作电位的作用(英文)

激活大麻素CB1受体(CB1Rs)通过调控多种离子通道,从而调节脊椎动物视网膜的功能。本文旨在利用膜片钳全细胞记录技术,在大鼠视网膜薄片上研究CB1Rs对神经节细胞兴奋性的作用。结果显示,在电流钳制状态下,灌流CB1R激动剂WIN55212-2(WIN,5μmol/L)对神经节细胞的自发动作电位发放频率和静息膜电位均没有显著影响。在灌流液中加入CNQX,D-APV,bicuculline和strychnine以阻断神经节细胞的兴奋性和抑制性输入,灌流5μmol/L WIN对正向电流注入(+10pA到+100pA)诱发的动作电位的频率也没有显著影响。位相分析结果显示,触发动作电位的阈值电位和触发第一个动作电位的延迟时间在加入WIN前后也没有显著改变;然而,WIN显著降低动作电位的上升和下降相速率(±dV/dtmax),而且该作用可被CB1R拮抗剂SR141716所阻断。此外,在阻断突触输入的情况下,WIN对神经节细胞的膜电位也没有显著影响。以上结果提示,激活大麻素CB1Rs通过调控诱发动作电位,从而调节大鼠视网膜神经节细胞的兴奋性。