Plasma levels of vascular endothelial growth factor and fibroblast growth factor 2 in patients with major depressive disorders.

We investigated the plasma levels of VEGF and FGF-2, important factors for regulation of neuroplasticity such as neurogenesis, in patients in remission from major depressive disorders (MDD). The plasma VEGF levels were significantly higher in the MDD patients than in the matched control subjects, while no significant difference in plasma FGF-2 levels was found. In particular, the MDD patients with family history of psychiatric disorders, but not patients without such a family history, showed significantly higher values of plasma VEGF than the controls. Although this is a preliminary study, altered VEGF levels might be involved in the pathophysiology of MDD.

Noradrenergic regulation of period1 expression in spinal astrocytes is involved in protein kinase A, c-Jun N-terminal kinase and extracellular signal-regulated kinase activation mediated by α1- and ß2-adrenoceptors.

Our recent data suggest that noradrenaline (NA) regulates expression of Per1 mRNA in rat C6 cells, as a model of brain astrocytes, by two distinct NA-mediating pathways. Although C6 cells possess potential astrocyte-type characteristics, we hypothesize that astrocytes located in a distinct tissue or organ play specific roles consistent with their own unique functions in response to the surrounding environment. We have herein found in primary rat spinal astrocytes using real-time RT-PCR that NA induced robust transient increases in Per1, Cry1, Cry2 and Bmal1 mRNA expression. Cry1, Cry2 and Bmal1 expressions induced by NA were attenuated by transfection of Per1 small interference RNA (siRNA). The effect of NA on Per1 expression was partially blocked by either prazosin (a selective antagonist of α1-adrenoceptor) or ICI118551 (a selective antagonist of ß2-adrenoceptor), and completely blocked by the combination of both antagonists. Treatment with H89 (a protein kinase A [PKA] inhibitor), SP600125 (a c-Jun N-terminal kinase [JNK] inhibitor), or PD98059 (an extracellular signal-regulated kinase [ERK] inhibitor), partially inhibited NA-induced Per1 mRNA expression, and the combination of these three inhibitors inhibited expression to nearly a non-stimulated level. Furthermore, NA phosphorylated not only ERK but also JNK1, an effect that was detected by western blotting. These actions were inhibited only by prazosin, and not by ICI118551. In addition, we found that NA induced phosphorylation of transcription-related proteins such as cAMP response element binding protein (CREB) and c-Jun. These phosphorylation processes were regulated through distinct pathways: CREB phosphorylation was dependent on the PKA and JNK pathways but c-Jun phosphorylation was mediated by the ERK and JNK pathways. These results suggest that Per1 plays a key role in noradrenergic regulation on clock gene expression in spinal astrocytes and activation of α1 and ß2 adrenoceptors are of importance in regulation of Per1 mRNA expression via PKA/JNK-CREB and ERK/JNK-c-Jun cascades.

Differential display of ethanol-induced gene in N18TG2 cells.

BACKGROUND: Recent advances in molecular biology, such as polymerase chain reaction (PCR) differential display, have enabled the screening of mRNAs transcriptionally regulated by chronic ethanol treatment. Screening of gene expression after ethanol exposure will be the most needed for new biological insights into alcoholism. METHODS: We used PCR differential display to detect differentially expressed RNAs in N18TG2 cells treated for 4 days with physiologic concentrations of ethanol (25 mM). RESULTS: We succeeded in identifying two differentially expressed RNAs in the ethanol-treated cells. The increase in the expression of the two RNAs was verified by Northern hybridization analysis. Sequence analyses and searches of the sequence databases revealed that one of the RNAs was that of the heat shock cognate protein 73 (HSC73) gene and that the other was the product of a novel gene. The increase in the level of HSC73 mRNA after ethanol administration was consistent with similar reports from other laboratories, and indicated that our assay system would be applicable to the screening of up-regulated gene expression during ethanol treatment. Rapid amplification of cDNA 5'-ends (5'-RACE) allowed us to determine the upstream sequence of the uncharacterized mRNA that would code for a protein of 113 amino acids. A homology search by MPsrch indicated very low homology to the calcium channel L-type alpha I subunit. CONCLUSIONS: The function of this new gene product is presently unknown, but our results indicate that an investigation of the pathophysiological significance of the gene in alcoholism would be worthwhile. Identification of genes that are influenced by chronic ethanol will certainly increase of the molecular mechanisms underlying physiologic dependence.

Antidepressant drug treatments induce glial cell line-derived neurotrophic factor (GDNF) synthesis and release in rat C6 glioblastoma cells.

Modulation of neurotrophic factors to protect neurons from damage is proposed as a novel mechanism for the action of antidepressants. However, the effect of antidepressants on modulation of glial cell line-derived neurotrophic factor (GDNF), which has potent and widespread effects, remains unknown. Here, we demonstrated that long-term use of antidepressant treatment significantly increased GDNF mRNA expression and GDNF release in time- and concentration-dependent manners in rat C6 glioblastoma cells. Amitriptyline treatment also increased GDNF mRNA expression in rat astrocytes. GDNF release continued for 24 h following withdrawal of amitriptyline. Furthermore, following treatment with antidepressants belonging to several different classes (amitriptyline, clomipramine, mianserin, fluoxetine and paroxetine) significantly increased GDNF release, but which did not occur after treatment with non-antidepressant psychotropic drugs (haloperidol, diazepam and diphenhydramine). Amitriptyline-induced GDNF release was inhibited by U0126 (10 microM), a mitogen-activated protein kinase (MAPK)-extracellular signal-related kinase (ERK) kinase (MEK) inhibitor, but was not inhibited by H-89 (1 microM), a protein kinase A inhibitor, calphostin C (100 nM), a protein kinase C inhibitor and PD 169316 (10 microM), a p38 mitogen-activated protein kinase inhibitor. These results suggested that amitriptyline-induced GDNF synthesis and release occurred at the transcriptional level, and may be regulated by MEK/MAPK signalling. The enhanced and prolonged induction of GDNF by antidepressants could promote neuronal survival, and protect neurons from the damaging effects of stress. This may contribute to explain therapeutic action of antidepressants and suggest new strategies of pharmacological intervention.