Histidine phosphorylation (pHis) was first reported in 1962. There are few studies on pHis because of the thermal and acidic instability of pHis and the lack of specific methods to detect it. pHis has two isomers of 1-phosphate histidine (1-pHis) and 3-phosphate histidine (3-pHis). pHis antibodies have been developed recently and have promoted research in this field. In this study, we established a CCl₄-induced liver fibrosis model in C57 mice and a TGF-β1-induced HSC activation model in LX-2 cells, to study the role of histidine phosphorylation. The expression of histidine kinases NME1 and NME2 was increased, histidine phosphatase PGAM5 and PHPT1 was unchanged, and 1-pHis and 3-pHis were increased in the in vivo and in vitro models. The expression of LHPP was decreased in the in vivo model but not in the in vitro model. To further study the role of NME1, NME2, and histidine phosphorylation in HSC activation, we silenced NME1 or NME2 and administered TGF-β1 in LX-2 cells. The results showed silencing NME1 or NME2 decreased TGF-β1-induced pHis levels and the expression of α-SMA and COL1A1, indicating the activation of HSC was suppressed. Then, we found the inhibitory effect on HSC activation is due to reduced phosphorylation of Smad2 and Smad3. In summary, our studies indicate that NME1 and NME2 are involved in TGF-β1-induced HSC activation and CCl₄-induced liver fibrosis, which may be mediated by histidine phosphorylation.

组氨酸磷酸化（pHis）于1962年首次报道。关于pHis的研究很少，因为pHis的热和酸不稳定性以及缺乏检测它的特定方法。pHis具有1-磷酸组氨酸（1-pHis）和3-磷酸组氨酸（3-pHis）的两种异构体。pHis抗体最近已经开发出来，并促进了该领域的研究。在这项研究中，我们建立了CCl ₄研究C57小鼠的肝纤维化模型和LX-2细胞的TGF-β1诱导的HSC激活模型，以研究组氨酸磷酸化的作用。在体内和体外模型中，组氨酸激酶NME1和NME2的表达增加，组氨酸磷酸酶PGAM5和PHPT1不变，并且1-pHis和3-pHis增加。LHPP的表达在体内模型中降低，但在体外模型中没有降低。为了进一步研究NME1，NME2和组氨酸磷酸化在HSC激活中的作用，我们沉默了NME1或NME2并在LX-2细胞中施用了TGF-β1。结果表明沉默NME1或NME2降低了TGF-β1诱导的pHis水平，α-SMA和COL1A1的表达，表明HSC的激活受到抑制。然后，我们发现对HSC活化的抑制作用是由于Smad2和Smad3磷酸化的降低。_4-诱导的肝纤维化，其可以由组氨酸磷酸化介导。