Department of Molecular and Cellular Pathology of Alcohol, Príncipe Felipe Research Center, Valencia, Spain.
Alcohol Clin Exp Res. 2017 Jul;41(7):1257-1270. doi: 10.1111/acer.13416. Epub 2017 Jun 5.
We previously showed that, by activating innate immune receptors Toll-like 4 (TLR4), adolescent intermittent ethanol (EtOH) exposure causes neuroinflammation, myelin damage, and behavioral dysfunctions. Recent findings reveal that clinically used opioid antagonists naltrexone (NT) and naloxone (NX) inhibit opioid-induced TLR4 signaling and that NT, NX, and nalmefene (NF), the 6-methylene derivative of NX, are able to reduce alcohol drinking escalation.
NF (0.1 mg/kg, intraperitoneally) was injected 1 hour prior to EtOH (3 g/kg, intraperitoneally) following intermittent treatment in female (PND35) adolescent mice. Inflammatory molecules, myelin proteins, and apoptotic markers were assessed in the prefrontal cortex (PFC) and striatum/nucleus accumbens (STR/NAcc). The effect of NF on alcohol drinking preference was evaluated in both the wild-type and TLR4 knockout (KO) adolescent mice. Using astroglial cells, the inhibitory potential of NT, NX, and NF on lipopolysaccharide (LPS), or the EtOH-triggered TLR4 response, was compared.
Our findings indicate that NF prevents the up-regulation of cytokines (IL-1β, IL-17A, TNF-α), chemokines (MCP-1, MIP-1, KC), and pro-inflammatory mediators (iNOS, COX-2), along with myelin damage and apoptotic events, in both PFC and STR/NAcc. NF also abolishes EtOH-induced escalation of alcohol preference/consumption, but has no effect when administered to TLR4-KO mice. In vitro experiments indicate that NX and NF inhibit TLR4 activation upon LPS or EtOH stimulation. Immunofluorescence studies and lipid rafts isolation show that NF is able to prevent TLR4 translocation to lipid rafts/caveolae in astrocytes.
These results suggest that NF prevents neuroinflammation and brain damage by blocking the TLR4 response and also support the role of central pro-inflammatory immune signaling in the modulation of alcohol consumption/addiction.
我们之前的研究表明，通过激活先天免疫受体 Toll 样受体 4（TLR4），青少年间歇性乙醇（EtOH）暴露会导致神经炎症、髓鞘损伤和行为功能障碍。最近的研究结果表明，临床上使用的阿片受体拮抗剂纳曲酮（NT）和纳洛酮（NX）可抑制阿片诱导的 TLR4 信号转导，并且 NT、NX 和纳美芬（NF），NX 的 6-亚甲基衍生物，能够减少酒精摄入的增加。
NF（0.1mg/kg，腹腔内注射）在雌性（PND35）青少年小鼠间歇性治疗后 1 小时预先给予 EtOH（3g/kg，腹腔内注射）。在额皮质（PFC）和纹状体/伏隔核（STR/NAcc）中评估炎症分子、髓鞘蛋白和凋亡标志物。NF 对青少年野生型和 TLR4 敲除（KO）小鼠饮酒偏好的影响进行了评估。使用星形胶质细胞，比较了 NT、NX 和 NF 对脂多糖（LPS）或 EtOH 触发的 TLR4 反应的抑制潜力。
我们的研究结果表明，NF 可防止细胞因子（IL-1β、IL-17A、TNF-α）、趋化因子（MCP-1、MIP-1、KC）和促炎介质（iNOS、COX-2）在上皮细胞和 STR/NAcc 中的上调，以及髓鞘损伤和凋亡事件。NF 还可消除 EtOH 诱导的酒精偏好/消耗增加，但在给予 TLR4-KO 小鼠时无影响。体外实验表明，NX 和 NF 可抑制 LPS 或 EtOH 刺激时 TLR4 的激活。免疫荧光研究和脂质筏分离表明，NF 能够阻止 TLR4 在星形胶质细胞中向脂质筏/小窝易位。
这些结果表明，NF 通过阻断 TLR4 反应来防止神经炎症和脑损伤，并支持中枢促炎免疫信号在调节酒精摄入/成瘾中的作用。
