Department of Neurosurgery, Affiliated Haikou Hospital, Xiangya School of Medicine, Central South University, Haikou 570208, China; Department of Physiology and Pharmacology, School of Medicine, Loma Linda University, Loma Linda, CA 92354, USA.
Department of Physiology and Pharmacology, School of Medicine, Loma Linda University, Loma Linda, CA 92354, USA; Department of Neurosurgery, Affiliated Yongchuan Hospital, Chongqing Medical University, Chongqing 402160, China.
Brain Behav Immun. 2021 Jan;91:615-626. doi: 10.1016/j.bbi.2020.09.032. Epub 2020 Oct 6.
Lysophosphatidic acid receptor 1 (LPA1) plays a critical role in proinflammatory processes in the central nervous system by modulating microglia activation. The aim of this study was to explore the anti-inflammatory effects and neurological function improvement of LPA1 inhibition after intracerebral haemorrhage (ICH) in mice and to determine whether prostaglandin E2 (PGE2), E-type prostaglandin receptor 2 (EP2), and NADPH oxidase 2 (NOX2) signalling are involved in LPA1-mediated neuroinflammation. ICH was induced in CD1 mice by autologous whole blood injection. AM966, a selective LPA1 antagonist, was administered by oral gavage 1 h and 12 h after ICH. The LPA1 endogenous ligand, LPA was administered to verify the effect of LPA1 activation. To elucidate potential inflammatory mechanisms of LPA1, the selective EP2 activator butaprost was administered by intracerebroventricular injection with either AM966 or LPA1 CRISPR knockout (KO). Water content of the brain, neurobehavior, immunofluorescence staining, and western blot were performed. After ICH, EP2 was expressed in microglia whereas LPA1 was expressed in microglia, neurons, and astrocytes, which peaked after 24 h. AM966 inhibition of LPA1 improved neurologic function, reduced brain oedema, and suppressed perihematomal inflammatory cells after ICH. LPA administration aggravated neurological deficits after ICH. AM966 treatment and LPA1 CRISPR KO both decreased the expressions of PGE2, EP2, NOX2, NF-κB, TNF-α, IL-6, and IL-1β expressions after ICH, which was reversed by butaprost. This study demonstrated that inhibition of LPA1 attenuated neuroinflammation caused by ICH via PGE2/EP2/NOX2 signalling pathway in mice, which consequently improved neurobehavioral functions and alleviated brain oedema. LPA1 may be a promising therapeutic target to attenuate ICH-induced secondary brain injury.
溶血磷脂酸受体 1（LPA1）通过调节小胶质细胞激活在中枢神经系统的促炎过程中发挥关键作用。本研究旨在探讨 LPA1 抑制在小鼠脑出血（ICH）后的抗炎作用和神经功能改善，并确定前列腺素 E2（PGE2）、E 型前列腺素受体 2（EP2）和 NADPH 氧化酶 2（NOX2）信号是否参与 LPA1 介导的神经炎症。通过自体全血注射在 CD1 小鼠中诱导 ICH。ICH 后 1 小时和 12 小时通过口服灌胃给予 LPA1 选择性拮抗剂 AM966。给予溶血磷脂酸（LPA），一种内源性 LPA1 配体，以验证 LPA1 激活的作用。为了阐明 LPA1 的潜在炎症机制，通过脑室内注射给予选择性 EP2 激活剂 butaprost，同时给予 AM966 或 LPA1 CRISPR 敲除（KO）。进行脑含水量、神经行为、免疫荧光染色和 Western blot。ICH 后，EP2 在小胶质细胞中表达，而 LPA1 在小胶质细胞、神经元和星形胶质细胞中表达，24 小时后达到峰值。AM966 抑制 LPA1 可改善 ICH 后的神经功能，减少脑水肿，并抑制血肿周围炎症细胞。ICH 后给予 LPA 可加重神经功能缺损。AM966 治疗和 LPA1 CRISPR KO 均降低了 ICH 后 PGE2、EP2、NOX2、NF-κB、TNF-α、IL-6 和 IL-1β 的表达，butaprost 逆转了这一作用。本研究表明，在小鼠中，通过 PGE2/EP2/NOX2 信号通路抑制 LPA1 可减轻 ICH 引起的神经炎症，从而改善神经行为功能并减轻脑水肿。LPA1 可能是减轻 ICH 继发性脑损伤的有前途的治疗靶点。
