A novel mechanism of neurovascular protection in ischemic tolerance

缺血耐受中神经血管保护的新机制

• 批准号: 9234076
• 负责人: Feng Zhang
• 金额: $ 33.69万
• 依托单位: UNIVERSITY OF PITTSBURGH AT PITTSBURGH
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-05-01 至 2020-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9234076
• 关键词: Acetylcysteine; Adherens Junction; Affect; Alteplase; Antioxidants; Astrocytes; Attenuated; Binding; Blood - brain barrier anatomy; Blood flow; Brain; Categories; Cause of Death; Cells; Cellular Structures; Chemical Structure; Clinic; Coculture Techniques; Cysteine; Data; Disease; Economic Burden; Elements; Endothelial Cells; Enzymes; Future; Generations; Genes; Gerbils; Glutamate-Cysteine Ligase; Hexenal; Hydrogen Peroxide; In Vitro; Infarction; Injury; Investigation; Ischemia; Ischemic Preconditioning; Ischemic Stroke; Knockout Mice; Lipid Peroxidation; Lipid Peroxides; Lipids; Mediating; Medicine; Methods; Middle Cerebral Artery Occlusion; Mus; Nervous System Physiology; Neurons; Nuclear; Omega-3 Fatty Acids; Omega-6 Fatty Acids; Outcome; Oxidative Stress; Pathway interactions; Permeability; Pharmacologic Substance; Phase; Phosphotransferases; Play; Protein Biosynthesis; Proteins; Rattus; Reaction; Research; Response Elements; Role; Route; Signal Transduction; Societies; Stroke; Sulfhydryl Compounds; Superoxide Dismutase; System; TXN gene; Testing; Translating; Work; base; beta-Transducin Repeat-Containing Proteins; cadherin 5; clinical translation; disability; enhancing factor; glycogen synthase kinase 3 beta; heme oxygenase-1; improved; in vivo; inhibitor/antagonist; multicatalytic endopeptidase complex; neuronal survival; neuroprotection; neurovascular; neurovascular unit; novel; particle; preconditioning; promoter; protective effect; public health relevance; small hairpin RNA; social; tool; transcription factor; ubiquitin-protein ligase

 DESCRIPTION (provided by applicant): Neurovascular units (NVU) are the structural and functional elements of the brain and are exquisitely susceptible to ischemic stroke. Stroke is the third leading cause of death and the leading cause of long-term disability, posing an enormous social and economic burden to society. Although the FDA has approved tissue plasminogen activator for restoring blood flow, no neuroprotective medicine is available for stroke victims. Ischemic preconditioning (IPC) has recently been shown to be able to induce ischemic tolerance of the brain against subsequent ischemic injury to the NVU; however, the underlying protective mechanisms are not clear. Using both in vitro and in vivo methods, we have obtained exciting preliminary results suggesting that IPC protects against ischemic injury via the transcription factor Nrf2 and the generation of endogenous lipid electrophiles that create mild oxidative stress. Suppressing Nrf2 or neutralizing electrophiles with N- acetylcysteine eliminates the ischemic tolerance. Electrophiles robustly activate Nrf2, induce phase 2 enzymes, and protect mouse brains, cultured rat primary cortical neurons, mouse brain microvessel endothelial cells (MBMEC), and astrocyte-endothelial cell co-cultures from ischemic injury. Furthermore, treating MBMEC cells with 4-HNE or preconditioning attenuates blood-brain barrier (BBB) damage induced by ischemia. The purpose of this proposal is to further investigate the mechanisms responsible for Nrf2 activation and neurovascular protection induced by IPC. The overall hypotheses are that IPC causes mild oxidative stress in the brain, leading to the generation of sublethal levels of lipid electrophiles; these electrophiles then activate the Nrf2 pathway by suppressing both Keap1 and GSK3ß, thereby protecting NVU components. Three specific aims are proposed: Aim 1 tests the hypotheses that IPC offers long-term neuroprotection against focal ischemia in mice and that Nrf2 and electrophiles are required for the sustained protection; Aim 2 tests the hypothesis that lipid electrophiles activate Nrf2 by inhibiting Keap1 and GSK3ß in NVU component cells; Aim 3 tests the hypothesis that IPC reinforces BBB via upreglulating CDH5 and that Nrf2 action protects the BBB and NVU in ischemic brain. This thorough investigation of the protective mechanisms of IPC may help develop future therapies that boost endogenous regulatory mechanisms in stroke victims.

 描述（由应用提供）：神经血管单元（NVU）是大脑的结构和功能元素，并且完全容易受到缺血性中风。中风是死亡的第三大主要原因，也是长期残疾的主要原因，对社会构成了巨大的社会和经济焚烧。尽管FDA已批准组织纤溶酶原激活剂来恢复血液，但最近已证明没有神经保护药物可用于中风缺血性预处理（IPC）（IPC）能够诱导大脑对随后缺血性损伤的缺血性耐受性；但是，基本的保护机制尚不清楚。使用体外和体内方法，我们获得了令人兴奋的初步结果，这表明IPC通过转录因子NRF2预防缺血性损伤，并产生内源性脂质电力，从而产生轻度的氧化物应激。用N-乙酰半胱氨酸抑制NRF2或中和电力可消除缺血性耐受性。电力物可牢固地激活NRF2，诱导2期酶，并保护小鼠大脑，培养的大鼠原发性皮质神经元，小鼠脑微血管内皮细胞（MBMEC）和星形胶质细胞 - 内皮细胞共培养物免受缺血性损伤。此外，用4-HNE或预处理治疗MBMEC细胞会减轻缺血引起的血脑屏障（BBB）损害。该提案的目的是进一步研究IPC引起的NRF2激活和神经血管保护的机制。总体假设是，IPC会导致大脑中的轻度氧化物应激，从而导致脂质电力的脂肪产生。然后，这些亲电器通过抑制KEAP1和GSK3ß来激活NRF2途径，从而保护NVU组件。提出了三个具体目的：目标1检验IPC在小鼠中对局灶性缺血的长期神经保护作用，并且需要NRF2和电力物来持续保护； AIM 2检验了以下假设：脂质电力通过抑制NVU组分细胞中的Keap1和GSK3ß激活NRF2。 AIM 3检验了以下假设：IPC通过上调CDH5增强BBB，并且NRF2作用保护缺血性大脑中的BBB和NVU。对IPC保护机制的彻底研究可能有助于发展未来的疗法，从而促进中风滥用中的内源性调节机制。