Dynamic regulation of phosphorylation of NMDA receptor GluN2B subunit tyrosine residues mediates ketamine rapid antidepressant effects.

The rapid antidepressant effects of ketamine depend on the N-methyl-D-aspartate (NMDA) receptor containing 2B subunit (NR2B), whose function is influenced by its phosphorylated regulation and distribution within and outside synapses. It remains unclear if ketamine's rapid onset of antidepressant effects relies on the dynamic phosphorylated regulation of NR2B within and outside synapses. Here, we show that ketamine rapidlyalleviated depression-like behaviors and normalized abnormal expression of pTyr1472NR2B and striatal-enriched protein tyrosine phosphatase (STEP) 61 within and outside synapses in the medial prefrontal cortex (mPFC) induced by chronic unpredictable stress (CUS) and conditional knockdown of STEP 61, a key phosphatase of NR2B, within 1 hour after administration Together, our results delineate the rapid initiation of ketamine's antidepressant effects results from the restoration of NR2B phosphorylation homeostasis within and outside synapses. The dynamic regulation of phosphorylation of NR2B provides a new perspective for developing new antidepressant strategies.

Enhancing excitatory projections from the ventral subiculum to the nucleus accumbens shell contribute to the MK-801-induced impairment of prepulse inhibition.

Prepulse inhibition (PPI), a measure of sensorimotor gating, has been shown to be disrupted in several animal models of neuropsychiatric disorders, such as schizophrenia. The neural circuits involving the hippocampus and nucleus accumbens (NAC) have been studied in rats to uncover the neurochemical and neuroanatomical substrates that regulate PPI. Majority of the studies of the hippocampus on PPI to date have been focused on CA1, CA2, and dentate gyrus (DG) area. Little is known about the role of the subiculum, which maintains the hippocampal formation intact, on the sensorimotor gating. In this study, the PPI disruption was induced by intraperitoneal injection of MK-801 in rats, and the neuronal activity in the dorsal and ventral subiculum by c-Fos immunostaining was examined. The projections from the subiculum to the nucleus accumbens (NAC) were detected by retrograde tracing of cholera toxin B subunit, in the PPI dysfunctional animals. The results showed an increase in neuronal activity in the ventral subiculum (vSub) while remaining constant in the dorsal subiculum during PPI disruption. The excitatory projections from the vSub to the NAC shell were significantly enhanced when PPI was disrupted. Muscimol Inhibition of vSub could significantly ameliorate the MK801-induced PPI deficit. This data suggests that the enhancement of neuronal activity in the vSub was associated with the PPI impairment, possibly due to the enhanced excitatory output from vSub the NAC shell.

[Screening of differential expression genes of human skin epidermal stem cells at different development stages by cDNA microarray technique].

OBJECTIVE: To analyze expression characteristics of human skin epidermal stem cell at different developmental stages, and to explore its biological significance. METHODS: Health skin samples from 28-32 w fetuses (F group), 4-12 y children (C group), and 35-55 y adult (A group) were harvested, with 10 cases in each group. Epidermis were separated using trypsin digestion and EDTA, and human epidermal stem cells were isolated and purified with type IV collagen attachment method. The monoclonal antibody of integrin beta1 and keratin 19 were used for detection and identification of epidermal stem cells by immunohistochemical staining. Total RNA was extracted from above cells by Trizol one-step method, and were detected by formaldehyde denaturing agarose gel electrophoresis. Probes were prepared and hybridized into cDNA microarray for scanning fluorescent signals and analysis of images, with two-fold differential expression value for screening. Significantly up/down-regulated genes were selected for verification by real time RT-PCR. RESULTS: By comparing expression profile between A and C groups, a total of 1808 genes with differential expression were detected, including 1089 up-regulated genes and 719 down-regulated genes, and they were classified into 128 categories. Among them, 1462 genes were known (found in GeneBank), 346 genes were unknown. A total of 4534 genes with differential expression were detected between C and F groups, in which 1783 genes were up-regulated and 2751 genes were down-regulated, and they were classified into 216 categories. Among them, 3577 genes were known (found in GeneBank), and 957 genes were unknown. There were 1104 genes with differential expression consistently detected in F, C and A groups, which were classified into 32 categories according to gene function. Among them, 94 genes were consistently up-regulated and 75 genes consistently down-regulated. Test results of real time RT-PCR were in accordance with above-mentioned results. CONCLUSIONS: Gene expression profiles of epidermal stem cells cultured in vitro, harvested from fetuses, children, and adult, exhibit obvious difference. This may be closely related to different stages of proliferation and differentiation of human epidermal stem cell and self-repair ability of wound at different developmental stages.