Lacroix Alexandre, Toussay Xavier, Anenberg Eitan, Lecrux Clotilde, Ferreirós Nerea, Karagiannis Anastassios, Plaisier Fabrice, Chausson Patrick, Jarlier Frédéric, Burgess Sean A, Hillman Elizabeth M C, Tegeder Irmgard, Murphy Timothy H, Hamel Edith, Cauli Bruno
Sorbonne Universités, UPMC Université Paris 06, Institut de Biologie Paris-Seine (IBPS), UM 119, Neuroscience Paris Seine, F-75005, Paris, France, CNRS, UMR 8246, Neuroscience Paris Seine, F-75005, Paris, France, INSERM, UMR-S 1130, Neuroscience Paris Seine, F-75005, Paris, France.
Sorbonne Universités, UPMC Université Paris 06, Institut de Biologie Paris-Seine (IBPS), UM 119, Neuroscience Paris Seine, F-75005, Paris, France, CNRS, UMR 8246, Neuroscience Paris Seine, F-75005, Paris, France, INSERM, UMR-S 1130, Neuroscience Paris Seine, F-75005, Paris, France, Laboratory of Cerebrovascular Research, Montreal Neurological Institute, McGill University, Montréal, Québec H3A 2B4, Canada.
J Neurosci. 2015 Aug 26;35(34):11791-810. doi: 10.1523/JNEUROSCI.0651-15.2015.
Vasodilatory prostaglandins play a key role in neurovascular coupling (NVC), the tight link between neuronal activity and local cerebral blood flow, but their precise identity, cellular origin and the receptors involved remain unclear. Here we show in rats that NMDA-induced vasodilation and hemodynamic responses evoked by whisker stimulation involve cyclooxygenase-2 (COX-2) activity and activation of the prostaglandin E2 (PgE2) receptors EP2 and EP4. Using liquid chromatography-electrospray ionization-tandem mass spectrometry, we demonstrate that PgE2 is released by NMDA in cortical slices. The characterization of PgE2 producing cells by immunohistochemistry and single-cell reverse transcriptase-PCR revealed that pyramidal cells and not astrocytes are the main cell type equipped for PgE2 synthesis, one third expressing COX-2 systematically associated with a PgE2 synthase. Consistent with their central role in NVC, in vivo optogenetic stimulation of pyramidal cells evoked COX-2-dependent hyperemic responses in mice. These observations identify PgE2 as the main prostaglandin mediating sensory-evoked NVC, pyramidal cells as their principal source and vasodilatory EP2 and EP4 receptors as their targets.
Brain function critically depends on a permanent spatiotemporal match between neuronal activity and blood supply, known as NVC. In the cerebral cortex, prostaglandins are major contributors to NVC. However, their biochemical identity remains elusive and their cellular origins are still under debate. Although astrocytes can induce vasodilations through the release of prostaglandins, the recruitment of this pathway during sensory stimulation is questioned. Using multidisciplinary approaches from single-cell reverse transcriptase-PCR, mass spectrometry, to ex vivo and in vivo pharmacology and optogenetics, we provide compelling evidence identifying PgE2 as the main prostaglandin in NVC, pyramidal neurons as their main cellular source and the vasodilatory EP2 and EP4 receptors as their main targets. These original findings will certainly change the current view of NVC.
血管舒张性前列腺素在神经血管耦合（NVC）中起关键作用，神经血管耦合是指神经元活动与局部脑血流之间的紧密联系，但其确切身份、细胞来源及相关受体仍不清楚。我们在大鼠中发现，NMDA诱导的血管舒张以及触须刺激引起的血流动力学反应涉及环氧合酶-2（COX-2）活性以及前列腺素E2（PgE2）受体EP2和EP4的激活。利用液相色谱-电喷雾电离-串联质谱法，我们证明NMDA在皮质切片中释放PgE2。通过免疫组织化学和单细胞逆转录酶-PCR对产生PgE2的细胞进行表征，结果显示锥体细胞而非星形胶质细胞是具备PgE2合成能力的主要细胞类型，三分之一的锥体细胞表达与PgE2合酶系统性相关的COX-2。与它们在NVC中的核心作用一致，在体光遗传学刺激锥体细胞在小鼠中引发了COX-2依赖性充血反应。这些观察结果确定PgE2是介导感觉诱发NVC的主要前列腺素，锥体细胞是其主要来源，血管舒张性EP2和EP4受体是其作用靶点。
脑功能严重依赖于神经元活动与血液供应之间永久的时空匹配，即神经血管耦合。在大脑皮质中，前列腺素是神经血管耦合的主要贡献者。然而，它们的生化特性仍然难以捉摸，其细胞来源仍存在争议。尽管星形胶质细胞可通过释放前列腺素诱导血管舒张，但在感觉刺激过程中该途径的参与情况受到质疑。通过从单细胞逆转录酶-PCR、质谱分析到离体和在体药理学及光遗传学等多学科方法，我们提供了令人信服的证据，确定PgE2是神经血管耦合中的主要前列腺素，锥体细胞是其主要细胞来源，血管舒张性EP2和EP4受体是其主要作用靶点。这些原创性发现必将改变目前对神经血管耦合的看法。
