Department of Basic Sciences, School of Medicine, Gonabad University of Medical Sciences, Gonabad, Iran.
Department of Neurosciences and Cognition, Faculty of Advanced Medical Sciences, Tabriz University of Medical Sciences, Tabriz, Iran; Stem Cell Research Center, Tabriz University of Medical Sciences, Tabriz, Iran.
Biomed Pharmacother. 2018 Jun;102:9-17. doi: 10.1016/j.biopha.2018.02.073. Epub 2018 Mar 14.
The end of linear chromosomes is formed of a special nucleoprotein heterochromatin structure with repetitive TTAGGG sequences called telomere. Telomere length is regulated by a special enzyme called telomerase, a specific DNA polymerase that adds new telomeric sequences to the chromosome ends. Telomerase consists of two parts; the central protein part and the accessory part which is a RNA component transported by the central part. Regulation of telomere length by this enzyme is a multi-stage process. Telomere length elongation is strongly influenced by the level of telomerase and has a strong correlation with the activity of telomerase enzyme. Human Telomerase Reverse Transcriptase (hTERT) gene expression plays an important role in maintaining telomere length and high proliferative property of cells. Except a low activity of telomerase enzyme in hematopoietic and few types of stem cells, most of somatic cells didn't showed telomerase activity. Moreover, cytokines are secretory proteins that control many aspects of hematopoiesis, especially immune responses and inflammation. Also, the induction of hTERT gene expression by cytokines is organized through the PI3K/AKT and NF/kB signaling pathways. In this review we have tried to talk about effects of immune cell cytokines on telomerase expression/telomere length and the induction of telomerase expression by cytokines.
线性染色体的末端由一种特殊的核蛋白异染色质结构形成，该结构带有称为端粒的重复 TTAGGG 序列。端粒长度由一种称为端粒酶的特殊酶调节，端粒酶是一种特殊的 DNA 聚合酶，可在染色体末端添加新的端粒序列。端粒酶由两部分组成；中央蛋白部分和辅助部分，辅助部分是由中央部分运输的 RNA 成分。该酶对端粒长度的调节是一个多阶段的过程。端粒长度的延长强烈受到端粒酶水平的影响，并且与端粒酶酶的活性具有很强的相关性。人端粒酶逆转录酶（hTERT）基因表达在维持端粒长度和细胞的高增殖特性方面起着重要作用。除了造血和少数类型的干细胞中端粒酶酶活性较低外，大多数体细胞都没有表现出端粒酶活性。此外，细胞因子是控制造血的许多方面，特别是免疫反应和炎症的分泌蛋白。此外，细胞因子诱导 hTERT 基因表达是通过 PI3K/AKT 和 NF/ kB 信号通路组织的。在这篇综述中，我们试图讨论免疫细胞细胞因子对端粒酶表达/端粒长度的影响，以及细胞因子诱导端粒酶表达。
