Vascular Biology Center and Division of Hematology-Oncology-Transplantation, Department of Medicine, University of Minnesota Medical School, 420 Delaware Street SE, Minneapolis, MN 55455, USA.
Am J Hematol. 2010 Jan;85(1):18-23. doi: 10.1002/ajh.21558.
Altered inflammation signaling within the cerebral vasculature may be an important risk factor for stroke in children with sickle cell anemia (SCA). This study examines how differential expression of NFkappaB/p65 (RelA), KLF2, and other transcription factors may act as switches in inflammation signaling leading to observed differences between non-SCA (NS) African Americans and African Americans with SCA who are either at risk (AR) or not at risk (NAR) of childhood stroke based on occurrence of Circle of Willis disease. Clover/Transfac analysis was used to identify overrepresented transcription factor binding motifs on genes associated with inflammation. Transcription factor binding motifs for the NFkappaB family and RFX1 were overrepresented on inflammation signaling gene set analysis. Variations in protein expression were determined by flow cytometry of blood outgrowth endothelial cells (BOECs) from NS, AR, and NAR donors and Western blots of protein extracts from both unstimulated and TNFalpha/IL1beta-stimulated BOECs. BOECs from patients with SCA had more cytoplasmic-derived RelA compared with NS BOECs. Sickle BOECs also had heightened responses to inflammatory stimuli compared with NS BOECs, as shown by increased nuclear RelA, and intracellular adhesion molecule (ICAM) response to TNFalpha/IL1beta stimulation. Multiple control points in RelA signaling were associated with risk of childhood stroke. The ratio of proinflammatory factor RelA to anti-inflammatory factor KLF2 was greater in BOECs from AR donors than NS donors. Group risk of childhood stroke with SCA was greatest among individuals who exhibited increased expression of proinflammatory transcription factors and decreased expression of transcription factors that suppress inflammation.
脑血管内炎症信号的改变可能是镰状细胞贫血（SCA）儿童中风的一个重要危险因素。本研究探讨了 NFkappaB/p65（RelA）、KLF2 和其他转录因子的差异表达如何作为炎症信号的开关，导致非 SCA（NS）非裔美国人和 SCA 非裔美国人之间观察到的差异，这些 SCA 患者要么存在（AR）要么不存在（NAR）儿童中风风险，这取决于 Willis 环疾病的发生。Clover/Transfac 分析用于识别与炎症相关基因的转录因子结合基序的过度表达。NFkappaB 家族和 RFX1 的转录因子结合基序在炎症信号基因集分析中过度表达。通过来自 NS、AR 和 NAR 供体的血液衍生的内皮细胞（BOEC）的流式细胞术和未刺激和 TNFalpha/IL1beta 刺激的 BOEC 蛋白提取物的 Western blot 确定蛋白表达的变化。与 NS BOEC 相比，SCA 患者的 BOEC 具有更多的细胞质衍生的 RelA。与 NS BOEC 相比，镰状细胞 BOEC 对炎症刺激的反应也更高，表现为核 RelA 增加和细胞内黏附分子（ICAM）对 TNFalpha/IL1beta 刺激的反应增加。RelA 信号的多个控制点与儿童中风的风险相关。来自 AR 供体的 BOEC 中促炎因子 RelA 与抗炎因子 KLF2 的比值大于 NS 供体。SCA 个体中，促炎转录因子表达增加和抑制炎症的转录因子表达减少与儿童中风的群体风险最高。
