Kadzielawa Konrad, Mathew Biji, Stelman Clara R, Lei Arden Zhengdeng, Torres Leianne, Roth Steven
Department of Anesthesiology, University of Illinois at Chicago, Chicago, IL, USA.
Center for Research Bioinformatics, University of Illinois at Chicago, Chicago, IL, USA.
Graefes Arch Clin Exp Ophthalmol. 2018 May;256(5):935-949. doi: 10.1007/s00417-018-3905-0. Epub 2018 Mar 5.
The pathophysiology of retinal ischemia involves mechanisms including inflammation and apoptosis. Ischemic post-conditioning (Post-C), a brief non-lethal ischemia, induces a long-term ischemic tolerance, but the mechanisms of ischemic post-conditioning in the retina have only been described on a limited basis. Accordingly, we conducted this study to determine the molecular events in retinal ischemic post-conditioning and to identify targets for therapeutic strategies for retinal ischemia.
To determine global molecular events in ischemic post-conditioning, a comprehensive study of the transcriptome of whole retina was performed. We utilized RNA sequencing (RNA-Seq), a recently developed, deep sequencing technique enabling quantitative gene expression, with low background noise, dynamic detection range, and discovery of novel genes. Rat retina was subjected to ischemia in vivo by elevation of intraocular pressure above systolic blood pressure. At 24 h after ischemia, Post-C or sham Post-C was performed by another, briefer period of ischemia, and 24 h later, retinas were collected and RNA processed.
There were 71 significantly affected pathways in post-conditioned/ischemic vs. normals and 43 in sham post conditioned/ischemic vs. normals. Of these, 28 were unique to Post-C and ischemia. Seven biological pathways relevant to ischemic injury, in Post-C as opposed to sham Post-C, were examined in detail. Apoptosis, p53, cell cycle, JAK-STAT, HIF-1, MAPK and PI3K-Akt pathways significantly differed in the number as well as degree of fold change in genes between conditions.
Post-C is a complex molecular signaling process with a multitude of altered molecular pathways. We identified potential gene candidates in Post-C. Studying the impact of altering expression of these factors may yield insight into new methods for treating or preventing damage from retinal ischemic disorders.
视网膜缺血的病理生理学涉及炎症和细胞凋亡等机制。缺血后处理（Post-C）是一种短暂的非致死性缺血，可诱导长期的缺血耐受，但视网膜缺血后处理的机制仅在有限的基础上得到描述。因此，我们进行了这项研究，以确定视网膜缺血后处理中的分子事件，并确定视网膜缺血治疗策略的靶点。
为了确定缺血后处理中的整体分子事件，我们对整个视网膜的转录组进行了全面研究。我们利用了RNA测序（RNA-Seq），这是一种最近开发的深度测序技术，能够进行定量基因表达分析，具有低背景噪声、动态检测范围和发现新基因的能力。通过将眼压升高至收缩压以上，使大鼠视网膜在体内发生缺血。缺血24小时后，通过另一段较短时间的缺血进行Post-C或假Post-C处理，24小时后收集视网膜并处理RNA。
与正常相比，Post-C/缺血组中有71条通路受到显著影响，假Post-C/缺血组中有43条通路受到显著影响。其中，28条通路是Post-C和缺血所特有的。详细研究了Post-C组与假Post-C组中与缺血损伤相关的7条生物学通路。凋亡、p53、细胞周期、JAK-STAT、HIF-1、MAPK和PI3K-Akt通路在不同条件下基因数量以及倍数变化程度上存在显著差异。
Post-C是一个复杂的分子信号传导过程，有多种分子通路发生改变。我们在Post-C中鉴定出了潜在的基因候选物。研究改变这些因子表达的影响可能会为治疗或预防视网膜缺血性疾病的损伤提供新的方法。
