Chelluboina Bharath, Warhekar Aditi, Dillard Matt, Klopfenstein Jeffrey D, Pinson David M, Wang David Z, Veeravalli Krishna Kumar
Department of Cancer Biology and Pharmacology, University of Illinois College of Medicine at Peoria, Peoria, IL, USA.
1] Department of Neurosurgery, University of Illinois College of Medicine at Peoria, Peoria, IL, USA [2] Comprehensive Stroke Center, Illinois Neurological Institue, Peoria, IL, USA.
Sci Rep. 2015 May 8;5:9504. doi: 10.1038/srep09504.
This study highlights the possible pathological role of MMP-12 in the context of ischemic stroke. Male rats were subjected to a two-hour middle cerebral artery occlusion (MCAO) procedure. MMP-12 shRNA expressing plasmid formulation was administered to these rats twenty-four hours after reperfusion. The results showed a predominant upregulation of MMP-12 (approximately 47, 58, 143, and 265 folds on days 1, 3, 5, 7 post-ischemia, respectively) in MCAO subjected rats. MMP-12 expression was localized to neurons, oligodendrocytes and microglia, but not astrocytes. Transcriptional inactivation of MMP-12 significantly reduced the infarct size. The percent infarct size was reduced from 62.87±4.13 to 34.67±5.39 after MMP-12 knockdown compared to untreated MCAO subjected rats. Expression of myelin basic protein was increased, and activity of MMP-9 was reduced in ischemic rat brains after MMP-12 knockdown. Furthermore, a significant reduction in the extent of apoptosis was noticed after MMP-12 knockdown. TNFα expression in the ipsilateral regions of MCAO-subjected rats was reduced after MMP-12 knockdown in addition to the reduced protein expression of apoptotic molecules that are downstream to TNFα signaling. Specific knockdown of MMP-12 after focal cerebral ischemia offers neuroprotection that could be mediated via reduced MMP-9 activation and myelin degradation as well as inhibition of apoptosis.
本研究强调了基质金属蛋白酶-12（MMP-12）在缺血性中风背景下可能的病理作用。雄性大鼠接受了两小时的大脑中动脉闭塞（MCAO）手术。在再灌注24小时后，将表达MMP-12短发夹RNA（shRNA）的质粒制剂给予这些大鼠。结果显示，在接受MCAO手术的大鼠中，MMP-12显著上调（在缺血后第1、3、5、7天分别约为47、58、143和265倍）。MMP-12表达定位于神经元、少突胶质细胞和小胶质细胞，但不在星形胶质细胞中。MMP-12的转录失活显著减小了梗死面积。与未处理的MCAO大鼠相比，MMP-12基因敲低后梗死面积百分比从62.87±4.13降至34.67±5.39。MMP-12基因敲低后，缺血大鼠脑中髓鞘碱性蛋白的表达增加，MMP-9的活性降低。此外，MMP-12基因敲低后凋亡程度显著降低。除了TNFα信号下游凋亡分子的蛋白质表达降低外，MMP-12基因敲低后，MCAO大鼠同侧区域的TNFα表达也降低。局灶性脑缺血后特异性敲低MMP-12可提供神经保护作用，这可能是通过降低MMP-9激活和髓鞘降解以及抑制凋亡来介导的。
