Brifault Coralie, Gras Marjorie, Liot Donovan, May Victor, Vaudry David, Wurtz Olivier
From the Institut National de la Santé et de la Recherche Médicale (INSERM) U982, Rouen, France (C.B., M.G., D.L., D.V., O.W.); Institute for Research and Innovation in Biomedicine, Normandy University, Rouen, France (C.B., M.G., D.L., D.V., O.W.); Laboratory of Neuronal and Neuroendocrine Differentiation and Communication, Rouen University, Mont-Saint-Aignan Cedex, France (C.B., M.G., D.L., D.V., O.W.); and Departments of Neurological Sciences and Pharmacology, University of Vermont College of Medicine, Burlington (V.M.).
Stroke. 2015 Feb;46(2):520-8. doi: 10.1161/STROKEAHA.114.006864. Epub 2014 Dec 30.
Until now, except thrombolysis, the therapeutical strategies targeting the acute phase of cerebral ischemia have been proven ineffective, and no approach is available to attenuate the delayed cell death mechanisms and the resulting functional deficits in the late phase. Then, we investigated whether a targeted and delayed delivery of pituitary adenylate cyclase-activating polypeptide (PACAP), a peptide known to exert neuroprotective activities, may dampen delayed pathophysiological processes improving functional recovery.
Three days after permanent focal ischemia, PACAP-producing stem cells were transplanted intracerebro ventricularly in nonimmunosuppressed mice. At 7 and 14 days post ischemia, the effects of this stem cell-based targeted delivery of PACAP on functional recovery, volume lesions, and inflammatory processes were analyzed.
The delivery of PACAP in the vicinity of the infarct zone 3 days post stroke promotes fast, stable, and efficient functional recovery. This was correlated with a modulation of the postischemic inflammatory response. Transcriptomic and Ingenuity Pathway Analysis-based bioinformatic analyses identified several gene networks, functions, and key transcriptional factors, such as nuclear factor-κB, C/EBP-β, and Notch/RBP-J as PACAP's potential targets. Such PACAP-dependent immunomodulation was further confirmed by morphometric and phenotypic analyses of microglial cells showing increased number of Arginase-1(+) cells in mice treated with PACAP-expressing cells specifically, demonstrating the redirection of the microglial response toward a neuroprotective M2 phenotype.
Our results demonstrated that immunomodulatory strategies capable of redirecting the microglial response toward a neuroprotective M2 phenotype in the late phase of brain ischemia could represent attractive options for stroke treatment in a new and unexploited therapeutical window.
迄今为止，除溶栓治疗外，针对脑缺血急性期的治疗策略均被证明无效，且尚无方法可减轻延迟性细胞死亡机制及后期由此导致的功能缺损。因此，我们研究了垂体腺苷酸环化酶激活多肽（PACAP，一种已知具有神经保护活性的肽）的靶向性延迟递送是否可抑制延迟性病理生理过程，改善功能恢复。
永久性局灶性缺血3天后，将产生PACAP的干细胞经脑室内移植到未进行免疫抑制的小鼠体内。在缺血后7天和14天，分析这种基于干细胞的PACAP靶向递送对功能恢复、梗死体积和炎症过程的影响。
中风后3天在梗死灶附近递送PACAP可促进快速、稳定且有效的功能恢复。这与缺血后炎症反应的调节相关。基于转录组学和 Ingenuity Pathway Analysis 的生物信息学分析确定了几个基因网络、功能以及关键转录因子，如核因子-κB、C/EBP-β和Notch/RBP-J作为PACAP的潜在靶点。通过对小胶质细胞的形态计量学和表型分析进一步证实了这种依赖PACAP的免疫调节，结果显示，在用表达PACAP的细胞治疗的小鼠中，精氨酸酶-1(+)细胞数量增加，这表明小胶质细胞反应重定向为具有神经保护作用的M2表型。
我们的结果表明，在脑缺血后期能够将小胶质细胞反应重定向为具有神经保护作用的M2表型的免疫调节策略，可能成为在一个新的未开发治疗窗口中治疗中风的有吸引力的选择。
