BDNF agonist treatment in experimental allergic encephalomyelitis

多发性硬化症(MS)的病理特征是炎症和神经变性。因为 目前治疗多发性硬化症的方法是免疫调节剂，但不能防止神经元丢失和残疾， 人们一直在寻求神经保护性治疗。脑源性神经营养因子是一种血液性营养因子 具有神经保护特性的细胞因子，已被研究为一种潜在的治疗方法。在一个动物模型中 MS，实验性变态反应性脑脊髓炎(EAE)，BDNF由免疫细胞产生，与 减少轴突丢失。BDNF存在于MS病变中，可能在病变的发病机制中起保护作用。 外源性应用BDNF的研究因其血清半衰期短和血脑功能差而受到限制。 屏障(BBB)渗透，因此我们进行了使用基因工程骨髓干细胞的研究 在EAE中交付BDNF。BDNF减少炎症和神经退行性变，我们的观察结果是 Linker等人(4)使用慢病毒递送系统证实了这一点。总之，这些研究表明，BDNF 治疗可减少EAE的炎症和神经变性。 2010年，Jang等人。报道称，7，8-二羟基黄酮(DHF)具有强大的脑源性神经营养因子激动剂活性，可以 口服给药，容易通过血脑屏障。在培养的神经元中，它激活了BDNF、TrkB和 下行信令。它保护野生型神经元，但不能保护TrkB缺陷的神经元免于凋亡。DHF已激活 TrkB对小鼠脑内红藻氨酸诱导的神经毒性的抑制作用，缩小实验性脑梗塞体积 TrkB依赖的小鼠卒中，并在帕金森病动物模型中具有神经保护作用 疾病。并非所有的DHF效应都依赖于TrkB：DHF具有NFKB依赖的抗炎活性 和抗氧化作用，可以减少炎症损伤。我们在C57BL/6小鼠中检测了DHF对MOG诱导的EAE的影响 并表明，即使在治疗的时候，治疗也能降低临床和病理严重程度 被推迟到出现症状时。总之，这些结果为进一步研究DHF提供了可能 治疗多发性硬化症 根据上面概述的结果，至少有四种可能的机制可以通过DHF 降低EAE的严重程度：它可以通过其抗氧化活性减轻炎性损伤，它可以减少 炎症通过非TrkB介导的途径，它可以通过TrkB介导的途径减轻炎症 对炎症细胞有作用，也可能对神经细胞有直接的TrkB介导的保护作用。我们 提出以下基本假设：DHF治疗MOG诱导的C57BL/6小鼠EAE可降低 疾病的临床和病理严重程度。我们提出以下次要假设：DHF 治疗MOG诱导的C57BL/6小鼠EAE可通过TrkB依赖机制降低疾病严重程度。 我们将通过完成以下具体目标来检验这些假设： 具体目标1：优化DHF给药剂量对C57BL/6小鼠MOG诱导的EAE模型的影响。 具体目标2：确定症状出现时开始的DHF治疗对中枢神经系统的影响 MOG诱导的C57BL/6小鼠EAE的炎症、免疫、脱髓鞘、轴突丢失和细胞凋亡。 特定目标#3：确定第50天开始的DHF治疗对中枢神经系统炎症、免疫、 MOG诱导的C57BL/6小鼠EAE脱髓鞘、轴突丢失和细胞凋亡 特定目标#4：确定DHF在MOG诱导的C57BL/6小鼠EAE中的作用是否是TrkB TrkBF616A基因敲除C57BL/6小鼠对DHF敏感性的测定 带和不带工作TrkB。 证实我们的假说将提供有关DHF治疗的重要新信息。 为MS患者DHF的研究提供理论依据。

Multiple sclerosis (MS) is characterized pathologically by inflammation and neurodegeneration. Because current treatments for MS, which are immune modulators, do not prevent neuronal loss and disability, neuroprotective treatments have been sought. Brain derived neurotrophic factor (BDNF) is a phleotrophic cytokine with neuroprotective properties that has been studied as a potential treatment. In an animal model of MS, experimental allergic encephalomyelitis (EAE), BDNF is produced by immune cells and is responsible for reducing axonal loss. BDNF is present in MS lesions and may play a protective role in lesion pathogenesis. Studies of exogenously administered BDNF have been limited by its short serum half-life and poor blood brain barrier (BBB) penetration so we conducted studies using genetically engineered bone marrow stem cells to deliver BDNF in EAE. BDNF reduced inflammation and neurodegeneration and our observations have been confirmed by Linker et al (4) using a lentivirus delivery system. Together these studies suggest that BDNF treatment reduces inflammation and neurodegeneration in EAE. In 2010 Jang et al. reported that 7,8-dihydroxyflavone (DHF) has potent BDNF agonist activity, can be given orally and readily crosses the BBB. In cultured neurons it activated the receptor for BDNF, TrkB, and downstream signaling. It protected wild-type, but not TrkB-deficient neurons from apoptosis. DHF activated TrkB in the mouse brain, inhibited kainic acid-induced neurotoxicity, decreased infarct volumes in experimental murine stroke in a TrkB-dependent manner, and was neuroprotective in an animal model of Parkinson's disease. Not all DHF effects are TrkB dependent: DHF has anti-inflammatory activity that is NFKB dependent and antioxidant effects that could reduce inflammatory injury. We tested DHF in MOG-induced EAE in C57Bl/6 mice and showed that treatment resulted in reduced clinical and pathological severity even when treatment was delayed until the onset of symptoms. Together these results support further studies of DHF as a possible treatment for MS. Based on the results outlined above, there are at least four possible mechanisms through with DHF could reduce the severity of EAE: It could reduce inflammatory injury through its antioxidant activity, it could reduce inflammation through a non-TrkB mediated pathway, it could reduce inflammation through a TrkB mediated effect on inflammatory cells or it could have a direct TrkB mediated protective effect on neuronal cells. We propose the following Primary Hypothesis: DHF treatment of MOG-induced EAE in C57Bl/6 mice reduces the clinical and pathological severity of disease. We propose the following Secondary Hypothesis: DHF treatment of MOG-induced EAE in C57Bl/6 mice reduces disease severity by a TrkB dependent mechanism. We will test these hypotheses by completing the following specific aims: Specific Aim #1: Optimize DHF dosing of C57Bl/6 mice with MOG-induced EAE. Specific Aim #2: Determine the effect of DHF treatment started at the time of symptom onset on CNS inflammation, immunity, demyelination, axonal loss and apoptosis in the MOG-induced EAE in C57Bl/6 mice. Specific Aim #3: Determine the effect of DHF treatment started on day 50 on CNS inflammation, immunity, demyelination, axonal loss and apoptosis in MOG-induced EAE in C57Bl/6 mice. Specific Aim #4: Determine whether the effect of DHF in MOG-induced EAE in C57Bl/6 mice is TrkB dependent by determining the sensitivity of the TrkBF616A knock-in C57Bl/6 mouse to the effects of DHF in mice with and without functioning TrkB. Confirming our hypotheses will provide important new information about the effects of DHF treatment in a model of MS and could provide a rationale for studies of DHF in MS patients.