铁稳态代谢表观遗传调控机制的研究进展

铁稳态在机体生长发育和健康维持中发挥重要作用，而机体铁稳态代谢受二价金属离子转运蛋白（DMT1）、转铁蛋白受体1（TFR1）、转铁蛋白受体2（TFR2）、铁外排蛋白（FPN）、铁调素（HAMP）、铁调素调节蛋白（HJV）、铁蛋白重链（Ferritin H）等关键基因精密调控。近年研究报道，DNA甲基化、组蛋白乙酰化和微RNA（miRNA）等表观遗传机制可发挥调控铁稳态的作用。其中，DNA甲基化可通过调控FPN、TFR2、HAMP、HJV和骨形态生成蛋白BMP家族成员6（BMP6）等铁代谢基因启动子区甲基化水平而影响这些基因的表达。此外，组蛋白脱乙酰酶（HDAC）能够通过抑制HAMP基因表达而调控铁代谢；而HDAC抑制剂可促进HAMP基因表达。多个miRNA可靶向DMT1、FPN、TFR1、TFR2和Ferritin H等基因，通过抑制这些铁代谢关键基因的表达而影响机体铁的吸收、转运、储存和利用过程。值得关注的是，表观遗传调控的一些关键酶，如DNA去甲基化酶TET2和组蛋白赖氨酸去甲基酶JmjC KDM需要铁离子才能发挥酶促活性。本文综述了DNA甲基化、组蛋白乙酰化和miRNA等表观遗传机制调控铁稳态代谢的国内外最新研究进展，并针对未来研究方向进行了讨论。

Progress on epigenetic regulation of iron homeostasis

Iron homeostasis plays an important role for the maintenance of human health. It is known that iron metabolism is tightly regulated by several key genes, including divalent metal transport-1(DMT1), transferrin receptor 1(TFR1), transferrin receptor 2(TFR2), ferroportin(FPN), hepcidin(HAMP), hemojuvelin(HJV) and Ferritin H. Recently, it is reported that DNA methylation, histone acetylation, and microRNA (miRNA) epigenetically regulated iron homeostasis. Among these epigenetic regulators, DNA hypermethylation of the promoter region of FPN, TFR2, HAMP, HJV and bone morphogenetic protein 6 (BMP6) genes result in inhibitory effect on the expression of these iron-related gene. In addition, histone deacetylase (HADC) suppresses HAMP gene expression. On the contrary, HADC inhibitor upregulates HAMP gene expression. Additional reports showed that miRNA can also modulate iron absorption, transport, storage and utilization via downregulation of DMT1, FPN, TFR1, TFR2, Ferritin H and other genes. It is noteworthy that some key epigenetic regulatory enzymes, such as DNA demethylase TET2 and histone lysine demethylase JmjC KDMs, require iron for the enzymatic activities. In this review, we summarize the recent progress of DNA methylation, histone acetylation and miRNA in regulating iron metabolism and also discuss the future research directions.