Attilio Peter J, Snapper Dustin M, Rusnak Milan, Isaac Akira, Soltis Anthony R, Wilkerson Matthew D, Dalgard Clifton L, Symes Aviva J
Graduate Program in Neuroscience, Uniformed Services University of the Health Sciences, Bethesda, MD, United States.
Department of Pharmacology and Molecular Therapeutics, Uniformed Services University of the Health Sciences, Bethesda, MD, United States.
Front Neurosci. 2021 Mar 22;15:636259. doi: 10.3389/fnins.2021.636259. eCollection 2021.
Traumatic brain injury (TBI) results in complex pathological reactions, where the initial lesion is followed by secondary inflammation and edema. Our laboratory and others have reported that angiotensin receptor blockers (ARBs) have efficacy in improving recovery from traumatic brain injury in mice. Treatment of mice with a subhypotensive dose of the ARB candesartan results in improved functional recovery, and reduced pathology (lesion volume, inflammation and gliosis). In order to gain a better understanding of the molecular mechanisms through which candesartan improves recovery after controlled cortical impact injury (CCI), we performed transcriptomic profiling on brain regions after injury and drug treatment. We examined RNA expression in the ipsilateral hippocampus, thalamus and hypothalamus at 3 or 29 days post injury (dpi) treated with either candesartan (0.1 mg/kg) or vehicle. RNA was isolated and analyzed by bulk mRNA-seq. Gene expression in injured and/or candesartan treated brain region was compared to that in sham vehicle treated mice in the same brain region to identify genes that were differentially expressed (DEGs) between groups. The most DEGs were expressed in the hippocampus at 3 dpi, and the number of DEGs reduced with distance and time from the lesion. Among pathways that were differentially expressed at 3 dpi after CCI, candesartan treatment altered genes involved in angiogenesis, interferon signaling, extracellular matrix regulation including integrins and chromosome maintenance and DNA replication. At 29 dpi, candesartan treatment reduced the expression of genes involved in the inflammatory response. Some changes in gene expression were confirmed in a separate cohort of animals by qPCR. Fewer DEGs were found in the thalamus, and only one in the hypothalamus at 3 dpi. Additionally, in the hippocampi of sham injured mice, 3 days of candesartan treatment led to the differential expression of 384 genes showing that candesartan in the absence of injury had a powerful impact on gene expression specifically in the hippocampus. Our results suggest that candesartan has broad actions in the brain after injury and affects different processes at acute and chronic times after injury. These data should assist in elucidating the beneficial effect of candesartan on recovery from TBI.
创伤性脑损伤（TBI）会导致复杂的病理反应，最初的损伤之后会继发炎症和水肿。我们实验室以及其他研究团队均已报道，血管紧张素受体阻滞剂（ARBs）对改善小鼠创伤性脑损伤后的恢复具有疗效。用亚降压剂量的ARB坎地沙坦治疗小鼠，可改善功能恢复，并减轻病理变化（损伤体积、炎症和胶质增生）。为了更好地了解坎地沙坦改善控制性皮质撞击伤（CCI）后恢复的分子机制，我们对损伤和药物治疗后的脑区进行了转录组分析。我们检测了在损伤后3天或29天用坎地沙坦（0.1mg/kg）或赋形剂处理的同侧海马体、丘脑和下丘脑的RNA表达。通过大量mRNA测序分离并分析RNA。将损伤和/或坎地沙坦处理的脑区中的基因表达与假手术赋形剂处理小鼠同一脑区中的基因表达进行比较，以鉴定组间差异表达的基因（DEGs）。大多数DEGs在损伤后3天在海马体中表达，并且DEGs的数量随着与损伤的距离和时间而减少。在CCI后3天差异表达的通路中，坎地沙坦治疗改变了参与血管生成、干扰素信号传导、细胞外基质调节（包括整合素）以及染色体维持和DNA复制的基因。在29天时，坎地沙坦治疗降低了参与炎症反应的基因的表达。通过qPCR在另一组动物中证实了基因表达的一些变化。在丘脑发现的DEGs较少，在损伤后3天在下丘脑中仅发现一个。此外，在假手术损伤小鼠的海马体中，3天的坎地沙坦治疗导致384个基因的差异表达，表明在无损伤的情况下坎地沙坦对基因表达有强大影响，特别是在海马体中。我们的结果表明，坎地沙坦在损伤后对大脑具有广泛作用，并在损伤后的急性和慢性时期影响不同的过程。这些数据应有助于阐明坎地沙坦对TBI恢复的有益作用。
