[Age-dependent expression of HSP90 in the hippocampus of APP/PS1 mice].

The present study aims to observe the change in expression of heat shock protein 90 (HSP90) along with amyloid-ß (Aß) and phosphorylated Tau (p-Tau) protein levels in the hippocampus tissue of Alzheimer's disease (AD) transgenic animal model with age. APP/PS1 transgenic mice at age of 6-, 9- and 12-month and C57BL/6J mice of the same age were used. The cognitive abilities of these animals were evaluated using a Morris water maze. Western blot or immunohistochemistry was used to detect the expressions of HSP90 and Aß1-42, as well as the phosphorylation levels of Tau protein in the hippocampus. The hsp90 mRNA levels and the morphology and number of cells in the hippocampus were detected with real-time quantitative polymerase chain reaction (qRT-PCR) and Nissl staining, respectively. The results showed that compared with C57BL/6J mice of the same age, HSP90 and hsp90 mRNA expression were decreased (P < 0.05 or P < 0.01), while Aß1-42 and p-Tau protein levels were increased (P < 0.05 or P < 0.01) in the hippocampal tissue of APP/PS1 transgenic mice. Meanwhile, the decrease in HSP90 and hsp90 mRNA expression (P < 0.05 or P < 0.01), the increase in Aß1-42 and p-Tau levels (P < 0.01 or P < 0.05) in hippocampal tissue and the reduction in behavioral ability showed a progressive development with the advancing of age in the APP/PS1 transgenic mice. In conclusion, in the hippocampal tissue of APP/PS1 mice, the decrease in HSP90 expression and the increase in Aß1-42 and p-Tau levels together with the decline of their cognitive ability are age-dependent.

[PTK2B affects the levels of Aß in blood and brain and behavioral functions via targeting LRP-1 transporter in Aß-induced cognitive dysfunction mice].

The aim of the present study was to explore the correlation between ptk2b/PTK2B (protein tyrosine kinase 2 beta, a ptk2b-encoded protein) and the level of low density lipoprotein receptor-related protein-1 (LRP-1), as well as to uncover the relationship between the changes in beta amyloid protein (Aß) levels in blood and brain and the expression of ptk2b in Aß-induced cognitive dysfunction mice. A total of 64 3-month-old C57BL/6J mice were divided randomly into the experimental group and control group. All mice underwent the intracerebroventricular (i.c.v.) intubation. Mice in the experimental group received the i.c.v. infusion of oligomeric Aß1-42 (0.1 µg/µL, 3.6 µL) to construct the cognitively impaired models, and three days later, those mice were further injected with PF431396 (an inhibitor of PTK2B, 15 µg/mL, Aß + PF group), phorbol-12-myristate-13-acetate (PMA, an agonist of PTK2B, 18.75 µg/mL, Aß + PMA group), RAP (an inhibitor of LRP-1, 0.2 µg/mL, Aß + RAP group) or normal saline (Aß + NS group). For mice in the control group, they underwent the i.c.v. infusion of NS, and 3 days later, they were additionally injected with PF431396 (PF group), PMA (PMA group), RAP (RAP group) or NS (NS group) in the volume of 2 µL. One week later, all mice were subjected to the determination of behavioral function in Morris water maze and the measurement of expression of Aß1-42, LRP-1 and PTK2B in blood and hippocampus using immunohistochemistry (IHC) staining, enzyme-linked immunosorbent assay (ELISA) and Western blot, and the measurement of mRNA expression of ptk2b in hippocampus using qRT-PCR. The results showed that the infusion of Aß induced an increase of Aß1-42 level in hippocampus and a decrease in blood, with the down-regulation of LRP-1 protein expression in hippocampus and up-regulation of mRNA and protein expression of ptk2b in hippocampus. For cognitively impaired mice, intervention of PF431396 caused the down-regulation of protein and mRNA expression of ptk2b in the hippocampus, while LRP-1 in hippocampus was up-regulated with a decrease in the level of Aß1-42 in hippocampus and an increase in the level of Aß1-42 in the blood, as well as significant improvement in cognitive function, while the administration of PMA resulted in the opposite changes. Moreover, the administration of RAP triggered the down-regulation of LRP-1 expression in hippocampus and an increase in the level of Aß1-42 in hippocampus and a decrease in the level of Aß1-42 in blood, with the deterioration of the behavioral functions, while protein and mRNA expression of ptk2b in hippocampus showed no evident changes. These results suggest that, in cognitively impaired mice, PTK2B, possibly via down-regulating LRP-1, increases the Aß1-42 level in brain, but decreases the Aß1-42 level in blood, thereby deteriorating the cognitive and behavioral functions of mice.

[Time dependent expression profiling of PTK2B and its relationship with Aß, Tau and LRP-1 in hippocampus and blood of APPswe/PS1dE9 double-transgenic mouse].

Objective: To uncover the time-dependent expression pattern of ptk2b gene and ptk2b-encoded protein, protein tyrosine kinase 2 beta(PTK2B), in the brain tissues of transgenic animal models of Alzheimer's disease (AD) and its relationship with the levels of Aß1-42, phosphorylation of Tau (p-Tau) and low density lipoprotein receptor-related protein-1(LRP-1) in blood and brain tissues. Methods: In this study, 5-, 10- and 15-month-old APPswe/PS1dE9 double-transgenic mice harboring the genotype of AD confirmed by the gene test were divided into the 5-, 10- and 15-month-old experiment groups, and simultaneously, age-matched C57BL/6J mice were placed into the corresponding control groups, with 8 mice in each group. All mice were subjected to the Morris Water Maze for test of cognitive and behavioral ability. Expression profiles of PTK2B, Aß1-42, p-Tau/Tau and LRP-1 in the hippocampus or blood of mice were quantified by using the immunohistochemistry staining, Western blot or enzyme-linked immunosorbent assay (ELISA), while the mRNA expression of ptk2b in the hippocampus was quantified by using the real-time quantitative polymerase chain reaction (qRT-PCR). Results: Results of experiment groups demonstrated that as mice aged, the expression levels of PTK2B, ptk2b mRNA, Aß1-42 and p-Tau/Tau in the hippocampus were increased, and the expression of LRP-1 was decreased gradually. While in the blood, the level of Aß1-42 was decreased, and the cognitive and behavioral ability was decreased in an age-dependent manner (all P＜ 0.05). However, comparisons among the control groups, only the age-dependent downregulation of LRP-1 were observed in hippocampus(P＜0.05), but other indicators had no significant differences (P＞0.05). Conclusion: In the hippocampus of APP/PS1 double-transgenic mice, the expressions of PTK2B, Aß1-42 and p-Tau/Tau are upregulated, LRP-1 is downregulated, while cognitive and behavioral ability is decreased, and such changes are presented in a time-dependent manner.

Histone deacetyltase 6 modulates amyloid ß-induced cognitive dysfunction rats by regulating protein tyrosine kinase 2 beta.

The aim of this study was to investigate the effects of histone deacetyltase (HDAC) 6 on the functional and pathological changes of the amyloid beta (Aß)-induced cognitive dysfunction rats by regulating protein tyrosine kinase 2 beta (PTK2B). Ninety Sprague-Dawley rats were randomly divided into nine groups, consisting of five experimental groups and four control groups. In five experimental groups, Aß1-42 was infused intracerebroventricularly and 3 days later, rats in each group were infused intracerebroventricularly with tubastatin A hydrochloride (TSA), the histone deacetyltase 6 (HDAC6)-specific inhibitor (Aß + TSA group), theophylline, the HDACs agonist (Aß + theophylline group), PF431396, the PTK2B inhibitor (Aß + PF group), the combination of PF431396 and theophylline (Aß + PF + theophylline group) and normal saline (Aß + normal saline group), respectively. Rats in four control groups took normal saline that was equivalent to the volume of Aß1-42, and 3 days later, TSA group, theophylline group, PF431396 (PF group), or normal saline group was given at a volume of 5 µL for rats in each group. Our results showed that HDAC6 may not only lead to the deterioration of learning and memory abilities but also elevate the levels of Aßo and Tau phosphorylation in Aß-induced cognitive dysfunction rats via up-regulating PTK2B.

Histone deacetylase-6 modulates amyloid beta-induced cognitive dysfunction rats by regulating PTK2B.

The aim of this study was to investigate the effects of histone deacetylase-6 (HDAC6) on the functional and pathological changes of the amyloid beta (Aß)-induced cognitive dysfunction rats by regulating protein tyrosine kinase 2 beta (PTK2B). Ninety Sprague Dawley rats were randomly divided into nine groups, consisting of five experimental groups and four control groups. In five experimental groups, Aß1-42 was infused intracerebroventricularly and 3 days later, rats in each group were infused intracerebroventricularly with tubastatin A hydrochloride (TSA), the HDAC6-specific inhibitor (Aß + TSA group), theophylline, the HDACs agonist (Aß + Theo group), PF431396 (PF), the PTK2B inhibitor (Aß + PF group), the combination of PF and theophylline (Aß + PF + Theo group), and normal saline (Aß + normal saline group), respectively. Rats in four control groups took normal saline that was equivalent to the volume of Aß1-42, and 3 days later, TSA (TSA group), theophylline (Theo group), (PF group, or normal saline group) was given at a volume of 5 µL for rats in each group. Our results showed that HDAC6 may not only lead to the deterioration of learning and memory abilities but also elevate the levels of Aßo and Tau phosphorylation in Aß-induced cognitive dysfunction rats via upregulating PTK2B.