Abstract

Striatal-enriched protein tyrosine phosphatase (STEP), which was initially identified in the striatum, is encoded by the Ptpn5 gene and is expressed in neurons of various structures of the brain. STEP is involved in regulating neuroplasticity, and its expression abnormalities are associated with human neurodegenerative disorders. The STEP inhibitor 8-trifluoromethyl-1,2,3,4,5-benzopentathiepin-6-amine hydrochloride (TC-2153) has been shown to affect the serotoninergic system of the brain. However, the influence of the serotoninergic system on the STEP regulation has not been studied yet. The aim of the study was to investigate how pharmacologically induced changes in the brain serotonin (5-HT) level affect Ptpn5 expression and STEP activity in adult male C57BL/6J mice. To modulate the 5-HT level in the brain, the 5-HT synthesis inhibitor p-chlorophenylalanine or 5-HT degradation inhibitor pargyline was administered intraperitoneally for three successive days. Changes in 5-HT concentration in the brain were assayed using high-performance liquid chromatography. The STEP activity was determined spectrophotometrically in the supernatant by the rate of p-nitrophenyl phosphate dephosphorylation in the absence and presence of the selective STEP inhibitor TC-2153. The Ptpn5 mRNA level was determined using quantitative RT-PCR. The Ptpn5 expression level in the striatum was three times higher than in the cortex and hippocampus. Both increases and decreases in brain 5-HT were for the first time associated with a decrease in Ptpn5 mRNA in the striatum. STEP activity in the striatum and cortex was significantly higher than in the hippocampus. However, p-chlorophenylalanine and pargyline did not affect the STEP activity in the brain structures tested. Thus, a new method was proposed to study the STEP activity in the brain and p-chlorophenylalanine and pargyline were shown to decrease Ptpn5 expression in the striatum in mice.

中文翻译：

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小鼠纹状体和р-氯苯丙氨酸降低编码纹状体富集蛋白酪氨酸磷酸酶（STEP）的Ptpn5的表达。

摘要

最初在纹状体中鉴定的富含纹状体的蛋白酪氨酸磷酸酶（STEP）由Ptpn5基因编码，并在大脑各种结构的神经元中表达。STEP参与调节神经可塑性，其表达异常与人类神经退行性疾病有关。已证明，STEP抑制剂8-三氟甲基-1,2,3,4,5-苯并五硫平-6-胺盐酸盐（TC-2153）可影响大脑的5-羟色胺能系统。然而，尚未研究5-羟色胺能系统对STEP调节的影响。该研究的目的是研究药理学诱导的脑5-羟色胺（5-HT）水平变化如何影响Ptpn5成年雄性C57BL / 6J小鼠体内的表达和STEP活性。为了调节脑中的5-HT水平，连续三天腹膜内施用5-HT合成抑制剂对氯苯丙氨酸或5-HT降解抑制剂精氨酸。使用高效液相色谱法测定大脑中5-HT浓度的变化。在不存在和存在选择性STEP抑制剂TC-2153的情况下，通过对硝基苯基磷酸酯的去磷酸化速率通过分光光度法测定上清液中的STEP活性。所述PTPN5使用定量RT-PCR测定mRNA水平。该PTPN5在纹状体中的表达水平比在皮质和海马中高三倍。脑内5-HT的增加和减少均与纹状体中Ptpn5 mRNA的减少有关。纹状体和皮质中的STEP活性显着高于海马中。但是，对氯苯丙氨酸和精氨酸并不影响所测试的大脑结构中的STEP活性。因此，提出了一种新的方法来研究脑中的STEP活性，并显示对氯苯丙氨酸和Pargyline降低了小鼠纹状体中Ptpn5的表达。