Changes of behavior and depression-like classic indicators after hippocampal microinjection of K252a / 中国比较医学杂志

Objective To study the changes of behavior and depression-like classic indicators after hippocampal microinjection of K252a,and to establish a new animal model of depression.Methods SD rats were randomly divided into five groups,namely the control group,sham group,chronic stress depression model group,hippocampal of K252a microinjection group,and hippocampal microinjection K252a plus chronic stress group.Open field experiments,sucrose consumption test,and Morris water maze behavioral assay were used to assess the behavioral changes in the rats.ELISA was used to detect the plasma monoamine neurotransmitter,radioimmunoassay was used to determine the plasma CRH,ACTH,CORT contents,and western-blotting was performed to observe the protein expression of BDNF,CREB,ERK1/2,and BCL-2 in the hippocampus.Results Compared with the control group,the amount of activity,sugar consumption,learning and memory abilities were decreased(P<0.05 or P<0.01),also the serum monoamine neurotransmitters were decreased (P<0.01),HPA axis function was improved (P<0.01),and the expression of BDNF,CREB,ERK1/2,BCL-2 decreased in the CUMS group(P<0.05 or P<0.01),but there was no significant difference in the DMSO group.Compared with the DMSO group,the activity,consumption of sucrose,learning and memory ability were significantly decreased(P<0.05 or P<0.01),while the HPA axis function was increased (P<0.05 or P<0.01),the serum monoamine neurotransmitters decreased(P<0.05 or P<0.01),and the BDNF,CREB,ERK1/2,BCL-2 expressions in the hypocampus were significantly decreased(P<0.05 or P<0.01) in the K252a group and K252a + CUMS group.Compared with the CUMS group,the K252a group and K252a + CUMS group did not show significant changes in these parameters.Compared with the K252a group,these indicators were not significantly changed in the K252a + CUMS group.Conclusions The results of behavior,hematology,and molecular biology analysis show that this model has a great similarity to the classical model of CUMS in surface validity,construct validity,and functional validity.It may provide an alternative investigative technology platform for basic research and antidepressant drug screening.

Effects of tyrosine kinase receptor B-brain-derived neurotrophic factor signal pathway on the secretion of vascular endothelial growth factor and matrix metalloproteinase-9 of neuroblastoma / 中国小儿急救医学

Objective To study the effects of tyrosine kinase receptor B-brain-derived neurotrophic factor (TrkB-BDNF) signal pathway on the secretion of vascular endothelial growth factor (VEGF) and matrix metalloproteinases-9(MMP-9) of neuroblastoma.Methods We used all-trans retinoic acid (ATRA) to induce the high expression of TrkB in the SH-SY5Y cell line,and then added the ectogenid BDNF to activate the TrkB-BDNF and its three downstream signal pathways.TrkB-BDNF signal pathway was inhibited by specific tyrosine kinase inhibitor K252a.The three downstream signal pathway was respectively inhibited by LY294002 (the phosphatidylinositol 3-hydroxy kinase (PI3 K) pathway inhibitor)、U73122 (the phospholipase C pathway inhibitor) 、U0126(the mitogen activated protein kinase pathway inhibitor).Enzyme linked immunosorbent assay was used to detect the concentration of VEGF and MMP-9 protein in the SY5Y cell culture supernatants.Results VEGF [(485.89 ± 109.99) pg/ml] and MMP-9 [(15.73 ± 1.72) pg/ml] protein levels in neuroblastoma cells cultured in serum-free media in the group of ATRA + BDNF were significantly higher than that of the control group and ATRA alone group(P ＜0.05).VEGF [(272.42 ±86.33) pg/ml]and MMP-9 [(5.25 ± 1.44) pg/ml] protein levels in the group of ATRA + BDNF + K252a were significantly lower than those of the ATRA + BDNF group(P ＜ 0.05) and had no significant difference compared with the control group and the ATRA alone group(P ＞0.05).VEGF [(314.12 ±24.68) pg/ml] and MMP-9 [(4.91 ± 1.08) pg/ml] protein levels in the group of ATRA + BDNF + LY294002 were significantly lower than those of the ATRA + BDNF group(P ＜ 0.05) and had no significant difference compared with the control group and the ATRA alone group(P ＞0.05).VEGF [(444.08 ±64.49) pg/ml] and MMP-9 [(13.28 ±3.38) pg/ml] protein levels in neuroblastoma cells cultured in serum-free media in the group of ATRA +BDNF + U73122 had no significant difference compared with the ATRA + BDNF group(P ＞ 0.05).VEGF [(429.97 ± 19.95) pg/ml] and MMP-9 [(13.96 ± 4.45) pg/ml] protein levels in neuroblastoma cells cultured in serum-free media in the group of ATRA + BDNF + U0126 had no significant difference compared with the ATRA + BDNF group(P ＞ 0.05).Conclusion Activation of TrkB-BDNF signal pathway can increase the synthesis and secretion of VEGF and MMP-9 in human neuroblastoma cells.TrkB-BDNF signal pathway may be through activating its downstream PI3K pathway to increase the synthesis and secretion of VEGF and MMP-9 in human neuroblastoma cells.The synthesis and secretion of VEGF and MMP-9 can be inhibited by blocking the TrkB-BDNF signal pathway with K252a or blocking its downstream signal pathway PI3 K with LY294002.

Effect of NGF on Cultured Human Retinal Capillary Endothelial Cells(HRCEC) / 中山大学学报(医学科学版)

[Objective] To observe NGF on cultured human retinal vascular endothelial cells (HRCEC) proliferation. [Methods] The MTT assay was used to analyze the impact of culture HRCEC on different factors (NGF concentration groups, NGF + K252a concentration groups, bFGF group, bFGF + K252a groups, the normal culture medium groups) in normal and hypoxic condition. [Results] With the increase of NGF concentration (20,50,100 ng/mL), HRCEC significantly increased (normal condition: 0.254±0.033,0.696±0.029, 1.136±0.051; hypoxic condition: 0.422±0.036, 0.798±0.044, 1.376±0.052, P< 0.05). Compared NGF + K252a group with the same concentration of NGF (100 ng/ml) group, HRCEC reduced (P<0.05), with increasing the concentration of K252a (50,100,200 nmol/L), the trend of HRCEC decreasing is become more significant (normal condition:0.864±0.067, 0.496±0.025, 0.202±0.078; hypoxic condition:K252a 1.042±0.047,0.700±0.065, 0.401±0.078, P<0.05). [Conclusion] NGF can promote the proliferation of HRCEC, the effect could be specifically blocked by TrkA inhibitor K252a.

Protein tyrosine kinase inhibitors modify kainic acid-induced epileptiform activity and mossy fiber sprouting but do not protect against limbic cell death

Intrahippocampal administration of kainic acid (KA) induces synaptic release of neurotrophins, mainly brain-derived neurotrophic factor, which contributes to the acute neuronal excitation produced by the toxin. Two protein tyrosine kinase inhibitors, herbimycin A and K252a, were administered intracerebroventricularly, in a single dose, to attenuate neurotrophin signaling during the acute effects of KA, and their role in epileptogenesis was evaluated in adult, male Wistar rats weighing 250-300 g. The latency for the first Racine stage V seizure was 90 ± 8 min in saline controls (N = 4) which increased to 369 ± 71 and 322 ± 63 min in animals receiving herbimycin A (1.74 nmol, N = 4) and K252a (10 pmol, N = 4), respectively. Behavioral alterations were accompanied by diminished duration of EEG paroxysms in herbimycin A- and K252a-treated animals. Notwithstanding the reduction in seizure severity, cell death (60-90 percent of cell loss in KA-treated animals) in limbic regions was unchanged by herbimycin A and K252a. However, aberrant mossy fiber sprouting was significantly reduced in the ipsilateral dorsal hippocampus of K252a-treated animals. In this model of temporal lobe epilepsy, both protein kinase inhibitors diminished the acute epileptic activity triggered by KA and the ensuing morphological alterations in the dentate gyrus without diminishing cell loss. Our current data indicating that K252a, but not herbimycin, has an influence over KA-induced mossy fiber sprouting further suggest that protein tyrosine kinase receptors are not the only factors which control this plasticity. Further experiments are necessary to elucidate the exact signaling systems associated with this K252a effect.

Inhibition effect of c-Met inhibitor on proliferation of lens epithelial cells / 国际眼科杂志(Guoji Yanke Zazhi)

AIM: To observe the inhibition of c-Met inhibitor on proliferation of lens epithelial cells (LECs).METHODS: Human's LECs were cultured and hepatocyte growth factor (HGF) and K252a were added to second passage of cells supplied with Dulbecco's modified eagle's medium (DMEM). MTT assay was used to examine the proliferation of LECs, and Western-blot was used to detect the expression change of Bcl-2 and Caspase-3.RESULTS: The photodensity (A) of HGF (50nmol/L) + K252a (30nmol/L) was not significantly different from that of DMEM control (P＞0.05). The expression of Bcl-2 and Caspase-3 were not significantly different from that in the control group.CONCLUSION: K252a, the inhibitor of c-Met, can effectively inhibit the proliferation of LECs.

Effect of neurotrophic tyrosine kinase receptor B on in vitro invasiveness of malignant transformed hFOB1.19 cells / 第三军医大学学报

Objective To study the effect of neurotrophic tyrosine kinase receptor B(TrKB) on in vitro invasiveness of malignant transformed hFOB1.19 cells and the role of TrKB in invasion and metastasis of osteosarcoma.Methods Expression of TrKB in malignant transformed hFOB1.19 cells and SaOS-2 osteosarcoma cells was detected by RT-PCR and immunofluorescence.Function of TrKB of malignant transformed hFOB1.19 cells was further studied.Malignant transformed hFOB1.19 cells were treated with specific tyrosine kinase inhibitor K252a for 24 h as a treatment group,and untreated malignant transformed hFOB1.19 cells into which DMSO was added served as a control group.Morphology of cells was observed under an inverted phase contrast microscope.Cell invasiveness was detected by Transwell assays.Microfilaments of cells were detected by actin immunofluorescence.Results The expression of TrKB was significantly higher in malignant transformed hFOB1.19 cells than in SaOS-2 osteosarcoma cells(P