Induction of DNA Hydroxymethylation Protects the Brain After Stroke
Induction of DNA Hydroxymethylation Protects the Brain After Stroke
复制标题
DOI：
10.1161/strokeaha.119.025665
复制
发表时间：
2019-09-01
期刊：
影响因子：
8.3
通讯作者：
Vemuganti, Raghu
中科院分区：
文献类型：
--
作者：
Morris-Blanco, Kahlilia C.;Kim, TaeHee;Vemuganti, Raghu
背景与目的-表观遗传学在脑病理中起着重要作用。我们目前评估了最近发现的富含大脑的表观遗传修饰，即5-羟甲基胞嘧啶（5hmC）在局灶性缺血性损伤后调节转录组学和致病机制中的作用。方法：采用一过性大脑中动脉闭塞的方法，对年轻、年老的雄性和雌性小鼠进行再灌注时梗死周围区域的观察。大脑中动脉闭塞前2天，在脑内注射抗5hmC产生酶TET（10 - 11转位酶）亚型的短干扰RNA。在再灌注后5分钟、30分钟或2小时腹腔注射抗坏血酸。用旋转杆和梁行走试验测试运动功能。结果-局灶性缺血可迅速诱导TET（一种催化5hmC形成的酶）的活性，并优先增加缺血皮质梗死周围区域TET3异构体的表达。5hmC水平以TET3依赖的方式增加，TET3的抑制导致参与抗氧化防御和DNA修复的神经保护基因的死后表达大规模减少。在成年雄性和雌性小鼠中，TET3敲低进一步增加局灶性缺血后的脑变性，表明TET3和5hmC具有内源性卒中保护作用。局灶性缺血后抗坏血酸治疗可增强梗死周围区域TET3活性和5hmC富集。抗坏血酸激活TET3对雌雄小鼠的缺血性损伤提供了强有力的保护。此外，抗坏血酸治疗改善了雄性和雌性小鼠的运动功能恢复。结论：总的来说，这些结果表明TET3和5hmC作为新的卒中治疗靶点的潜力。
Background and Purpose- Epigenetics play a significant role in brain pathologies. We currently evaluated the role of a recently discovered brain-enriched epigenetic modification known as 5-hydroxymethylcytosine (5hmC) in regulating transcriptomic and pathogenic mechanisms after focal ischemic injury. Methods- Young and aged male and female mice were subjected to transient middle cerebral artery occlusion, and the peri-infarct region was analyzed at various times of reperfusion. Two days before middle cerebral artery occlusion, short-interfering RNA against an isoform of the 5hmC producing enzyme TET (ten-eleven translocase) was injected intracerebrally. Ascorbate was injected intraperitoneally at 5 minutes, 30 minutes, or 2 hours of reperfusion. Motor function was tested with rotarod and beam-walk test. Results- Focal ischemia rapidly induced the activity of TET, the enzyme that catalyzes the formation of 5hmC and preferentially increased expression of the TET3 isoform in the peri-infarct region of the ischemic cortex. Levels of 5hmC were increased in a TET3-dependent manner, and inhibition of TET3 led to wide-scale reductions in the postischemic expression of neuroprotective genes involved in antioxidant defense and DNA repair. TET3 knockdown in adult male and female mice further increased brain degeneration after focal ischemia, demonstrating a role for TET3 and 5hmC in endogenous protection against stroke. Ascorbate treatment after focal ischemia enhanced TET3 activity and 5hmC enrichment in the peri-infarct region. TET3 activation by ascorbate provided robust protection against ischemic injury in young and aged mice of both sexes. Moreover, ascorbate treatment improved motor function recovery in both male and female mice. Conclusions- Collectively, these results indicate the potential of TET3 and 5hmC as novel stroke therapeutic targets.