Phosphorylation of transcription factor specificity protein 4 is increased in peripheral blood mononuclear cells of first-episode psychosis

BACKGROUND: Altered expression of transcription factor specificity protein 4 (SP4) has been found in the postmortem brain of patients with psychiatric disorders including schizophrenia and bipolar disorder. Reduced levels of SP4 protein have recently been reported in peripheral blood mononuclear cells in first-episode psychosis. Also, SP4 levels are modulated by lithium treatment in cultured neurons. Phosphorylation of SP4 at S770 is increased in the cerebellum of bipolar disorder subjects and upon inhibition of NMDA receptor signaling in cultured neurons. The aim of this study was to investigate whether SP4 S770 phosphorylation is increased in lymphocytes of first-episode psychosis patients and the effect of lithium treatment on this phosphorylation. METHODS: A cross-sectional study of S770 phosphorylation relative to total SP4 immunoreactivity using specific antibodies in peripheral blood mononuclear cells in first-episode psychosis patients (n = 14, treated with lithium or not) and matched healthy controls (n = 14) by immunoblot was designed. We also determined the effects of the prescribed drugs lithium, olanzapine or valproic acid on SP4 phosphorylation in rat primary cultured cerebellar granule neurons. RESULTS: We found that SP4 S770 phosphorylation was significantly increased in lymphocytes in first-episode psychosis compared to controls and decreased in patients treated with lithium compared to patients who did not receive lithium. Moreover, incubation with lithium but not olanzapine or valproic acid reduced SP4 phosphorylation in rat cultured cerebellar granule neurons. CONCLUSIONS: The findings presented here indicate that SP4 S770 phosphorylation is increased in lymphocytes in first-episode psychosis which may be reduced by lithium treatment in patients. Moreover, our study shows lithium treatment prevents this phosphorylation in vitro in neurons. This pilot study suggests that S770 SP4 phosphorylation could be a peripheral biomarker of psychosis, and may be regulated by lithium treatment in first-episode psychosis

Phosphorylation of transcription factor specificity protein 4 is increased in peripheral blood mononuclear cells of first-episode psychosis

Altered expression of transcription factor specificity protein 4 (SP4) has been found in the postmortem brain of patients with psychiatric disorders including schizophrenia and bipolar disorder. Reduced levels of SP4 protein have recently been reported in peripheral blood mononuclear cells in first-episode psychosis. Also, SP4 levels are modulated by lithium treatment in cultured neurons. Phosphorylation of SP4 at S770 is increased in the cerebellum of bipolar disorder subjects and upon inhibition of NMDA receptor signaling in cultured neurons. The aim of this study was to investigate whether SP4 S770 phosphorylation is increased in lymphocytes of first-episode psychosis patients and the effect of lithium treatment on this phosphorylation.A cross-sectional study of S770 phosphorylation relative to total SP4 immunoreactivity using specific antibodies in peripheral blood mononuclear cells in first-episode psychosis patients (n = 14, treated with lithium or not) and matched healthy controls (n = 14) by immunoblot was designed. We also determined the effects of the prescribed drugs lithium, olanzapine or valproic acid on SP4 phosphorylation in rat primary cultured cerebellar granule neurons.We found that SP4 S770 phosphorylation was significantly increased in lymphocytes in first-episode psychosis compared to controls and decreased in patients treated with lithium compared to patients who did not receive lithium. Moreover, incubation with lithium but not olanzapine or valproic acid reduced SP4 phosphorylation in rat cultured cerebellar granule neurons.The findings presented here indicate that SP4 S770 phosphorylation is increased in lymphocytes in first-episode psychosis which may be reduced by lithium treatment in patients. Moreover, our study shows lithium treatment prevents this phosphorylation in vitro in neurons. This pilot study suggests that S770 SP4 phosphorylation could be a peripheral biomarker of psychosis, and may be regulated by lithium treatment in first-episode psychosis

Phosphorylation of transcription factor specificity protein 4 is increased in peripheral blood mononuclear cells of first-episode psychosis

BACKGROUND: Altered expression of transcription factor specificity protein 4 (SP4) has been found in the postmortem brain of patients with psychiatric disorders including schizophrenia and bipolar disorder. Reduced levels of SP4 protein have recently been reported in peripheral blood mononuclear cells in first-episode psychosis. Also, SP4 levels are modulated by lithium treatment in cultured neurons. Phosphorylation of SP4 at S770 is increased in the cerebellum of bipolar disorder subjects and upon inhibition of NMDA receptor signaling in cultured neurons. The aim of this study was to investigate whether SP4 S770 phosphorylation is increased in lymphocytes of first-episode psychosis patients and the effect of lithium treatment on this phosphorylation. METHODS: A cross-sectional study of S770 phosphorylation relative to total SP4 immunoreactivity using specific antibodies in peripheral blood mononuclear cells in first-episode psychosis patients (n = 14, treated with lithium or not) and matched healthy controls (n = 14) by immunoblot was designed. We also determined the effects of the prescribed drugs lithium, olanzapine or valproic acid on SP4 phosphorylation in rat primary cultured cerebellar granule neurons. RESULTS: We found that SP4 S770 phosphorylation was significantly increased in lymphocytes in first-episode psychosis compared to controls and decreased in patients treated with lithium compared to patients who did not receive lithium. Moreover, incubation with lithium but not olanzapine or valproic acid reduced SP4 phosphorylation in rat cultured cerebellar granule neurons. CONCLUSIONS: The findings presented here indicate that SP4 S770 phosphorylation is increased in lymphocytes in first-episode psychosis which may be reduced by lithium treatment in patients. Moreover, our study shows lithium treatment prevents this phosphorylation in vitro in neurons. This pilot study suggests that S770 SP4 phosphorylation could be a peripheral biomarker of psychosis, and may be regulated by lithium treatment in first-episode psychosis

Specificity proteins 1 and 4, hippocampal volume and first-episode psychosis

We assessed specificity protein 1 (SP1) and 4 (SP4) transcription factor levels in peripheral blood mononuclear cells and conducted a voxel-based morphometry analysis on brain structural magnetic resonance images from 11 patients with first-episode psychosis and 14 healthy controls. We found lower SP1 and SP4 levels in patients, which correlated positively with right hippocampal volume. These results extend previous evidence showing that such transcription factors may constitute a molecular pathway to the development of psychosis.</p

SP4 phosphorylation at S770 is reduced by lithium chloride treatment.

<p><b>A.</b> Cerebellar granule neurons were treated with serum-free media containing 25mM KCl for two hours in the presence of the indicated concentrations of lithium chloride <b>(A)</b>, valproic acid (VPA) <b>(B)</b> or olanzapine (OLZ) <b>(C)</b>. 14 μg <b>(A)</b> or 5 μg <b>(B and C)</b> of a total protein extracts were analyzed by Western blot using antisera to phospho-SP4 S770, total SP4, phospho-GSK3β S9 (a positive control for lithium treatment) <b>(A)</b>, phospho-Tau S396 (a positive control for VPA) <b>(B)</b>, p42/44 MAPK (a positive control for OLZ) <b>(C)</b> and GAPDH as a loading control. The graphs show the densitometric quantification of S770 phosphorylated SP4 relative to the levels of total SP4. Statistical analysis was performed using ANOVA followed by Bonferroni’s post hoc comparison between untreated condition and the different doses of drugs. N = 3 (**p<0.01).</p

Phospho-SP4 S770 is increased in peripheral blood mononuclear cells of patients with first-episode psychosis compared to control subjects and this increase is not present in those patients with lithium prescription.

<p>Immunoreactivity of phospho-SP4 S770, SP4 and β-actin was determined in the same protein extracts from peripheral blood mononuclear cells (PBMC) of control (C, n = 14), and first-episode psychosis (FEP, n = 14) individuals. The resultant bands were quantified by densitometry. Both phospho-SP4 (pSP4) and SP4 were normalized to β-actin values and referred to a standard sample in two independent immunoblot analysis for pSP4 and SP4. pSP4/SP4 ratio was calculated for these samples by referring the mean normalized phospho-SP4 immunoreactivity levels to the mean normalized total SP4 immunoreactivity. Final pSP4/SP4 values were normalized to the mean of control group. Levels of total SP4 immunoreactivity normalized to β-actin were reported previously [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0125115#pone.0125115.ref019" target="_blank">19</a>]. <b>(A)</b> Images show representative pSP4, SP4, and β-actin immunoblots from four control individuals and four FEP subjects. Patients FEP₂ and FEP₄ were both receiving lithium treatment. <b>(B)</b> The graph shows the mean and standard deviation of the normalized pSP4/SP4 ratio for control and FEP groups. Each value represents the mean of two independent analyses. One sample in FEP group had to be excluded from the analysis due to almost undetectable levels of pSP4 and SP4 (n = 13). Statistical analysis was performed using one-tailed Mann-Whitney test. <b>(C)</b> The graph shows the mean and standard deviation of normalized pSP4/SP4 ratio for FEP patients without lithium treatment (Untreated, n = 7), and FEP patients with lithium treatment (Treated, n = 6). Each value represents the mean of two independent analyses. An outlier was detected for pSP4/SP4 ratio in the lithium treated group using the Peirce criterion and therefore excluded from the analysis (n = 5). Statistical analysis was performed using two-tailed Mann-Whitney test. <b>(D)</b> The graph shows the mean and standard deviation of normalized total SP4 immunoreactivity for FEP patients without lithium treatment, and FEP patients with lithium treatment. Each value represents the mean of two independent analyses. Statistical analysis was performed using two-tailed Mann-Whitney test. (*p<0.05; n.s., not significant).</p

Demographic and clinical features of cases (n = 28).

<p>Adapted from [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0125115#pone.0125115.ref019" target="_blank">19</a>]. Mean ± standard deviation or relative frequency are shown for each variable; FEP, first-episode psychosis; APd, antipsychotic dose; PANSS, Positive and Negative Syndrome Scale; CDS, Calgary Depression Scale; YMRS, Young Mania Rating Scale; Li, lithium; VA, valproic acid; N/A, not applicable.</p><p>^a Mann-Whitney U is shown for non-parametric variables.</p><p>^b χ² and degrees of freedom are shown for qualitative variables.</p><p>^c Chlorpromazine equivalent dose was calculated based on the electronic records of drug prescriptions of the patients [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0125115#pone.0125115.ref029" target="_blank">29</a>].</p><p>Demographic and clinical features of cases (n = 28).</p