P11 Expression Research Articles

P11 mediates the BDNF-protective effects in dendritic outgrowth and spine formation in B27-deprived primary hippocampal cells

Backgroundp11 (S100A10) is a key regulator of depression-like behaviors and antidepressant drug response in rodent models. Recent studies suggest that p11 mediates the behavioral antidepressant action of brain-derived neurotrophic factor (BDNF) in rodents. BDNF improves neural plasticity, which is linked to the cellular actions of antidepressant drugs. In the present study, we investigated whether p11 regulated BDNF action on neural plasticity in vitro. MethodsWe generated primary hippocampal cultures. p11 expression, total dendritic length, and spine density were investigated under toxic conditions induced by B27 deprivation, which causes hippocampal cell death. ResultsB27 deprivation significantly decreased p11 expression. Treatment with BDNF significantly prevented the B27 deprivation-induced decrease in p11 levels in a concentration-dependent manner, whereas these concentrations had no effect on control cultures. B27 deprivation significantly reduced the total length of hippocampal dendrites and spine density. BDNF increased the total dendritic length and spine density in conditions with or without B27. Furthermore, p11 knockdown through small interfering RNA (siRNA) transfection blocked these effects. The overexpression of p11 in B27-deprived cells increased the total dendritic length and spine density, and treatment with BDNF potentiated these effects. LimitationThis study should be confirmed in animal models of depression. ConclusionTaken together, our data suggest that BDNF-induced improvement in neural plasticity may depend on the regulation of p11 in hippocampal cells with B27 deprivation. These results provide evidence to strengthen the theoretical basis of a role for p11 in BDNF-induced antidepressant action.

Gene therapy blockade of dorsal striatal p11 improves motor function and dyskinesia in parkinsonian mice

Complications of dopamine replacement for Parkinson's disease (PD) can limit therapeutic options, leading to interest in identifying novel pathways that can be exploited to improve treatment. p11 (S100A10) is a cellular scaffold protein that binds to and potentiates the activity of various ion channels and neurotransmitter receptors. We have previously reported that p11 can influence ventral striatal function in models of depression and drug addiction, and thus we hypothesized that dorsal striatal p11 might mediate motor function and drug responses in parkinsonian mice. To focally inhibit p11 expression in the dorsal striatum, we injected an adeno-associated virus (AAV) vector producing a short hairpin RNA (AAV.sh.p11). This intervention reduced the impairment in motor function on forced tasks, such as rotarod and treadmill tests, caused by substantia nigra lesioning in mice. Measures of spontaneous movement and gait in an open-field test declined as expected in control lesioned mice, whereas AAV.sh.p11 mice remained at or near normal baseline. Mice with unilateral lesions were then challenged with l-dopa (levodopa) and various dopamine receptor agonists, and resulting rotational behaviors were significantly reduced after ipsilateral inhibition of dorsal striatal p11 expression. Finally, p11 knockdown in the dorsal striatum dramatically reduced l-dopa-induced abnormal involuntary movements compared with control mice. These data indicate that focal inhibition of p11 action in the dorsal striatum could be a promising PD therapeutic target to improve motor function while reducing l-dopa-induced dyskinesias.

P11 modulates calcium handling through 5-HT4R pathway in rat ventricular cardiomyocytes

BackgroundThe role of the serotonin receptor 4 (5-HT4R) pathway in cardiac excitation-contraction coupling (ECC) remains unclear. In the brain, induction of the calcium (Ca2+)-binding protein p11 enhances 5-HT4R translocation and signaling and could therefore be considered as a modulator of the 5-HT4R pathway in the myocardium. p11 expression is increased by brain-derived neurotrophic factor (BDNF) or antidepressant drugs (imipramine). Thus, we investigated whether p11 regulates the 5-HT4R pathway in the heart in physiological conditions or under pharmacological induction and the effects on calcium handling. Methods and resultsp11 expression was induced in vivo in healthy Wistar rats by imipramine (10mg/kg/21 days) and in vitro in left ventricular cardiomyocytes exposed to BDNF (50ng/ml/8h). Cell shortening and real-time Ca2+ measurements were processed on field-stimulated intact cardiomyocytes with the selective 5-HT4R agonist, prucalopride (1μM). Both imipramine and BDNF-induced cardiomyocyte p11 expression unmasked a strong response to prucalopride characterized by an increase of both cell shortening and Ca2+ transient amplitude compared to basal prucalopride associated with a high propensity to trigger diastolic Ca2+ events. Healthy rats treated with BDNF (180 ng/day/14 days) exhibited a sustained elevated heart rate following a single injection of prucalopride (0.1mg/kg) which was not observed prior to treatment. ConclusionsWe have identified a novel role for p11 in 5-HT4R signaling in healthy rat ventricular cardiomyocytes. Increased p11 expression by BDNF and imipramine unraveled a 5-HT4R-mediated modulation of cardiac Ca2+ handling and ECC associated with deleterious Ca2+ flux disturbances. Such mechanism could partly explain some cardiac adverse effects induced by antidepressant treatments.

0330: Cardiac p11 expression is related to 5-HT4 receptor pathway in failing and non-failing rat left ventricular cardiomyocytes

Heart failure is the inability to maintain a sufficient cardiac output necessary to meet metabolic demand. Cellular compensatory mechanisms, such as the serotonin 4 receptor (5-HT4R) pathway, take place to improve the defective cardiac excitation-contraction coupling (CEC). However, little is known about the regulation of this pathway. Our objective was to investigate the potential involvement of the 5-HT4R partner p11 in the activation of the pathway during heart failure. Wistar rats underwent ligation of the left coronary artery to mimic infarction. Control Sham-operated animals underwent the same surgery without ligation. Seven weeks post myocardial infarction (PMI) hearts were collected and/or enzymatically digested in order to perform biochemical studies or to assess intracellular calcium (Ca 2+ ) handling at the single cell level. p11 mRNA expression in the left posterior wall was significantly increased at 7 weeks PMI compared to Sham (272±40 vs.141±27 A.U, P<0.05). However, p11 protein levels in 7 weeks PMI myocytes showed a trend toward a decrease compared to sham (0,16±0,02 vs. 0,25±0,09). Interestingly, the expression of the p11 partner Annexin A2 was significantly increased (1,52±0.32 vs. 0,53±0.14, P<0.05) suggesting improved p11 stability. At the CEC level, stimulation of the 5-HT4R pathway by prucalopride did not exert an effect on all CEC parameters evaluated in both PMI and Sham myocytes. Nevertheless, induction of p11 expression by Brain-Derived Neuron Factor treatment in freshly isolated healthy myocytes showed a remarkable increase in Ca2+ transient amplitude (0,27±0,02 vs. 0,18±0,01, P<0.05) and basal Ca2+level (0,67±0,01 vs. 0,64±0,01, P<0.05) following prucalopride stimulation compared to untreated cells. Cardiac expression of p11 seems to play a role in the modulation of the response to 5-HT4R pathway in both failing and non-failing hearts.

Cell-Type Specific Expression of p11 Controls Cocaine Reward

The high rate of comorbidity between depression and cocaine addiction suggests shared molecular mechanisms and anatomical pathways. Limbic structures, such as the nucleus accumbens (NAc), play a crucial role in both disorders, yet how different cell types within these structures contribute to the pathogenesis remains elusive. Downregulation of p11 (S100A10), specifically in the NAc, elicits depressive-like behaviors in mice, but its role in drug addiction is unknown. We combined mouse genetics and viral strategies to determine how the titration of p11 levels within the entire NAc affects the rewarding actions of cocaine on behavior (six to eight mice per group) and molecular correlates (three experiments, five to eight mice per group). Finally, the manipulation of p11 expression in distinct NAc dopaminoceptive neuronal subsets distinguished cell-type specific effects of p11 on cocaine reward (five to eight mice per group). We demonstrated that p11 knockout mice have enhanced cocaine conditioned place preference, which is reproduced by the focal downregulation of p11 in the NAc of wild-type mice. In wild-type mice, cocaine reduced p11 expression in the NAc, while p11 overexpression exclusively in the NAc reduced cocaine conditioned place preference. Finally, we identified dopamine receptor-1 expressing medium spiny neurons as key mediators of the effects of p11 on cocaine reward. Our data provide evidence that disruption of p11 homeostasis in the NAc, particularly in dopamine receptor-1 expressing medium spiny neurons, may underlie pathophysiological mechanisms of cocaine rewarding action. Treatments to counter maladaptation of p11 levels may provide novel therapeutic opportunities for cocaine addiction.

Early responses to deep brain stimulation in depression are modulated by anti-inflammatory drugs

Deep brain stimulation (DBS) in the subgenual cingulated gyrus (SCG) is a promising new technique that may provide sustained remission in resistant major depressive disorder (MDD). Initial studies reported a significant early improvement in patients, followed by a decline within the first month of treatment, an unexpected phenomenon attributed to potential placebo effects or a physiological response to probe insertion that remains poorly understood. Here we characterized the behavioural antidepressant-like effect of DBS in the rat medial prefrontal cortex, focusing on modifications to rodent SCG correlate (prelimbic and infralimbic (IL) cortex). In addition, we evaluated the early outcome of DBS in the SCG of eight patients with resistant MDD involved in a clinical trial. We found similar antidepressant-like effects in rats implanted with electrodes, irrespective of whether they received electrical brain stimulation or not. This effect was due to regional inflammation, as it was temporally correlated with an increase of glial-fibrillary-acidic-protein immunoreactivity, and it was blocked by anti-inflammatory drugs. Indeed, inflammatory mediators and neuronal p11 expression also changed. Furthermore, a retrospective study indicated that the early response of MDD patients subjected to DBS was poorer when they received anti-inflammatory drugs. Our study demonstrates that electrode implantation up to the IL cortex is sufficient to produce an antidepressant-like effect of a similar magnitude to that observed in rats receiving brain stimulation. Moreover, both preclinical and clinical findings suggest that the use of anti-inflammatory drugs after electrode implantation may attenuate the early anti-depressive response in patients who are subjected to DBS.

6r, a novel oxadiazole analogue of ethacrynic acid, exhibits antitumor activity both in vitro and in vivo by induction of cell apoptosis and S-phase arrest

This study investigated the in vitro and in vivo antitumor effects of 5-[2,3-Dichloro-4-(2-methylene-1-oxobutyl) phenoxymethyl]-3-methyl-1,2,4- oxadiazole (6r), a novel ethacrynic acid (EA) derivative. The in vitro effect of 6r on cell proliferation of human colon, leukemia, prostate, lung, breast, ovarian and cervical tumor cell lines was assessed using MTT assay and the in vivo effect was determined with an SW620 xenografts nude mice model. The effect of 6r on expressions of GST P1-1 and apoptosis-related proteins were measured by western blotting and the effect on cell apoptosis was analysed by Hoechst 33258 nuclear staining as well as by cell surface staining of annexin V/propidium iodide. The effect on cell cycle was assessed by flow cytometry. Results showed that 6r inhibit proliferation of a range of human cancer cells in vitro and growth of SW620 tumor xenografts in vivo. The anti-proliferative effect of 6r is associated with cell apoptosis as a result of increased ratio of cellular Bax/bcl-2 expression and subsequent cytochrome-c and caspase-3 activation. Unlike EA, 6r did not show any influence on cellular GST P1-1 expression and its anti-proliferative action was associated with cell cycle arrest in G1/S-phase. In conclusion, 6r has the potential to be developed as a chemotherapeutic agent by induction of cell apoptosis but not regulating GST P1-1.

TLS-CHOP represses miR-486 expression, inducing upregulation of a metastasis regulator PAI-1 in human myxoid liposarcoma

Myxoid liposarcomas (MLSs) are characterized by t(12;16)(q13;p11) translocation and expression of TLS-CHOP chimeric oncoprotein. However, the molecular functions of TLS-CHOP have not been fully understood. On the other hand, microRNAs (miRNAs) comprise an abundant class of endogenous small non-coding RNAs that negatively regulate the expression of their target genes, and are involved in many biological processes. It is now evident that dysregulation of miRNAs is an important step in the development of many cancers. To our knowledge, however, there have been no reports of the miRNAs involved in MLS tumorigenesis and development. In this study, we have found that miR-486 expression was repressed in TLS-CHOP-expressed NIH3T3 fibroblasts and MLS tissues, and exogenous overexpression of miR-486 repressed growth of MLS cells. Thus, downregulation of miR-486 may be an important process for MLS. In addition, we have identified plasminogen activator inhibitor-1 (PAI-1) as a novel target gene of miR-486. PAI-1 is a unique type of serine protease inhibitor and is known to be one of the key regulators of tumor invasion and metastasis. Furthermore, knockdown of PAI-1 by a specific small interfering RNA (siRNA) inhibited growth of MLS cells, suggesting that increased expression of PAI-1 by miR-486 repression is critical for survival of MLS cells. Collectively, these results suggest a novel essential molecular mechanism that TLS-CHOP activates PAI-1 expression by repression of miR-486 expression in MLS tumorigenesis and development.

Interferon‐γ stimulates p11‐dependent surface expression of annexin A2 in lung epithelial cells to enhance phagocytosis

Annexin A2 (p36) is usually present together with its natural ligand p11 as a heterotetramer complex, which has multiple biological functions depending on its cellular localization. However, the detailed mechanism of annexin A2 translocation and its physiological role in inflammation remain unclear. Here, we show that IFN-γ stimulation enhances surface translocation of annexin A2 on lung epithelial cells. While total annexin A2 protein remains unchanged, the expression of p11 is upregulated via the IFN-γ-activated JAK2/STAT1 signal pathway. Notably, IFN-γ-induced p11 expression is required for annexin A2 translocation to the cell surface. Since annexin A2 lacks a signal peptide for surface translocation by the classical endoplasmic reticulum-Golgi route, its mode of trafficking remains unclear. We observed that p11-dependent surface translocation of annexin A2 is associated with the exosomal secretion pathway. The IFN-γ-induced increase of annexin A2 in the exosomes is blocked in p11-silenced cells. Furthermore, IFN-γ-induced surface expression of annexin A2 mediates phagocytosis of apoptotic cells by lung epithelial cells. These findings provide insights into the surface translocation mechanism of annexin A2 and illustrate a pivotal function of surface annexin A2 in the phagocytic response to IFN-γ.

Silencing of GSTP1, a Prostate Cancer Prognostic Gene, by the Estrogen Receptor-β and Endothelial Nitric Oxide Synthase Complex

We recently identified in prostate tumors (PCa) a transcriptional prognostic signature comprising a significant number of genes differentially regulated in patients with worse clinical outcome. Induction of up-regulated genes was due to chromatin remodeling by a combinatorial complex between estrogen receptor (ER)-β and endothelial nitric oxide synthase (eNOS). Here we show that this complex can also repress transcription of prognostic genes that are down-regulated in PCa, such as the glutathione transferase gene GSTP1. Silencing of GSTP1 is a common early event in prostate carcinogenesis, frequently caused by promoter hypermethylation. We validated loss of glutathione transferase (GST) P1-1 expression in vivo, in tissue microarrays from a retrospective cohort of patients, and correlated it with decreased disease-specific survival. Furthermore, we show that in PCa cultured cells ERβ/eNOS causes GSTP1 repression by being recruited at estrogen responsive elements in the gene promoter with consequential remodeling of local chromatin. Treatment with ERβ antagonist or its natural ligand 5α-androstane-3β,17β-diol, eNOS inhibitors or ERβ small interference RNA abrogated the binding and reversed GSTP1 silencing, demonstrating the direct involvement of the complex. In vitro, GSTP1 silencing by ERβ/eNOS was specific for cells from patients with worse clinical outcome where it appeared the sole mechanism regulating GSTP1 expression because no promoter hypermethylation was present. However, in vivo chromatin immunoprecipitation assays on fresh PCa tissues demonstrated that silencing by ERβ/eNOS can coexist with promoter hypermethylation. Our findings reveal that the ERβ/eNOS complex can exert transcriptional repression and suggest that this may represent an epigenetic event favoring inactivation of the GSTP1 locus by methylation. Moreover, abrogation of ERβ/eNOS function by 3β-adiol emphasizes the significance of circulating or locally produced sex steroid hormones or their metabolites in PCa biology with relevant clinical/therapeutic implications.

P11 expression and PET in bipolar disorders

Background Bipolar disorder (BD) is a common mental disorder, subdivided into BD-I and BD-II. Currently, few biomarkers differentiate BD-I from BD-II. However, it is suggested that peripheral blood mononuclear cell (PBMC) mRNA levels of p11 and positron emission tomography (PET) might be potential biomarkers for BD. Methods Healthy controls (HCs), BD-I, and BD-II patients in remission ( n = 20 in each group) underwent a resting PET study with the radiotracer [ 18F]-2-deoxy-2-fluoro- d-glucose ( 18F-FDG). PBMC p11 mRNA levels were determined by quantitative real-time PCR. Results Comparing BD patients to HCs, normalized glucose metabolism (NGM) was higher in the hippocampus, parahippocampus, and amygdala, but lower in the anterior cingulate cortex (aCC), medial prefrontal cortex (mPFC), dorsolateral prefrontal cortex (dlPFC), insula and thalamus. Compared to BD-II, BD-I had hypometabolism of glucose in the aCC, bilateral middle and inferior gyrus, insula and striatum, and hypermetabolism of glucose in the left parahippocampus. PBMC p11 mRNA was over-expressed in both BD-I and BD-II, although there was no significant difference in its expression levels between BD-I and B-II patients. Further, there were significant positive correlations between PBMC p11 mRNA and NGM in the mPFC, aCC, left insula, bilateral orbitofrontal cortex (OFC), and left middle, inferior and superior temporal gyri. Also, PBMC p11 mRNA was positively correlated to the number of depressive episodes in BD patients, especially in BD-I patients. Discussion This study demonstrates that PBMC p11 mRNA expression is associated with neural activation in the brain of BD patients and warrants a larger translational study to determine its clinical utility.

The antidepressive effect of the physical exercise correlates with increased levels of mature BDNF, and proBDNF proteolytic cleavage-related genes, p11 and tPA

Clinical studies show an evident antidepressive effect of physical exercise and animal research corroborate such evidence. However, the neurobiological mechanisms underlying the antidepressive effect of exercise are not completely understood. Notwithstanding, it is known that exercise increases brain-derived neurotrophic factor (BDNF) expression in the hippocampus similarly to antidepressant drugs. BDNF is synthesized as a precursor molecule that undergoes a proteolytic cleavage to generate either a mature or a truncated isoform. Precursor and mature BDNF are assumed to elicit opposing biological effects in neuroplasticity. In the present study we investigated the effect of voluntary physical activity on precursor and mature brain-derived neurotrophic factor levels and on proBDNF cleavage related genes, p11 and tissue plasminogen activator (tPA), as well as the antidepressive and cognitive effects of voluntary physical activity. Mice had access to mobile or locked running wheels for 28 days and were submitted to forced-swim, tail suspension and water maze tests. Their hippocampi were dissected and analyzed by Western blot and real time RT-PCR. Voluntary physical activity, but not locked wheel exposure, induced a robust increase in hippocampal mature BDNF protein levels, as well as in p11 and tPA mRNA expression; and also promoted antidepressive effects and improved learning, when compared with sedentary mice. On the other hand, there were no significant differences between any groups in the expression of precursor or truncated isoforms of BDNF. Our data suggest that the antidepressive effect of the physical exercise may depend, at least in part, on changes in BDNF post-translational processing.

Glucocorticoid-induced p11 over-expression and chromatin remodeling: A novel molecular mechanism of traumatic stress?

While the actions of glucocorticoids on brain function have been comprehensively studied, understanding of the underlying genomic mechanisms is advancing slowly. Recently, it was found that p11 is associated with traumatic stress and depression, and glucocorticoids regulate expression of the p11 gene. The ligand-activated glucocorticoid receptor (GR) interacts with two glucocorticoid response elements (GREs) in the p11 promoter region to up-regulate the p11 gene. RU486, a glucocorticoid receptor antagonist, and mutation of GREs both block glucocorticoid-induced p11 over-expression, suggesting that glucocorticoid-induced p11 over-expression is mediated by GR and GREs. Thus, the p11 gene can be transcriptionally activated. There is evidence that this transcriptional activation is mediated by the remodeling of chromatin complexes in response to glucocorticoid receptor-regulated promotors. The regulation of eukaryotic gene expression by chromatin remodeling is complex and is essential for numerous cellular processes. The association of linker-histone, non-histone and heterochromatin-specific proteins plays a key role in the generation of higher-order chromatin structures. Understanding the chromatin remodeling involved in the glucocorticoid-mediated increase of p11 expression by stress may clarify stress-induced over-expression of p11 and also identify a new therapeutic target for post-traumatic disorder and depressive disorders, i.e., chromatin remodeling.

Reversal of Depressed Behaviors in Mice by p11 Gene Therapy in the Nucleus Accumbens

The etiology of major depression remains unknown, but dysfunction of serotonergic signaling has long been implicated in the pathophysiology of this disorder. p11 is an S100 family member recently identified as a serotonin 1B [5-hydroxytryptamine 1B (5-HT(1B))] and serotonin 4 (5-HT(4)) receptor-binding protein. Mutant mice in which p11 is deleted show depression-like behaviors, suggesting that p11 may be a mediator of affective disorder pathophysiology. Using somatic gene transfer, we have now identified the nucleus accumbens as a key site of p11 action. Reduction of p11 with adeno-associated virus (AAV)-mediated RNA interference in the nucleus accumbens, but not in the anterior cingulate, of normal adult mice resulted in depression-like behaviors nearly identical to those seen in p11 knockout mice. Restoration of p11 expression specifically in the nucleus accumbens of p11 knockout mice normalized depression-like behaviors. Human nucleus accumbens tissue shows a significant reduction of p11 protein in depressed patients when compared to matched healthy controls. These results suggest that p11 loss in rodent and human nucleus accumbens may contribute to the pathophysiology of depression. Normalization of p11 expression within this brain region with AAV-mediated gene therapy may be of therapeutic value.

A Role for p11 in the Antidepressant Action of Brain-Derived Neurotrophic Factor

The protein p11 (also called S100A10) is downregulated in human and rodent depressive-like states. Considerable experimental evidence also implicates p11 in the mechanism of action of antidepressant drugs and electroconvulsive seizures, in part due to its interaction with specific serotonin receptors. Brain-derived neurotrophic factor (BDNF) has been linked to the therapeutic activity of antidepressants in rodent models and humans. In the current study, we investigated whether BDNF regulates p11 in vitro and in vivo. We utilized primary neuronal cultures, in vivo analyses of transgenic mice, and behavioral techniques to assess the effects of BDNF on p11. Results indicate that BDNF stimulates p11 expression through tropomyosin-related kinase B (trkB) receptors and via the mitogen-activated protein kinase signaling pathway. Brain-derived neurotrophic factor-induced changes in p11 in vivo correlate with changes in ligand binding to the 5-hydroxytryptamine receptor 1B, the subcellular localization of which is known to be regulated by p11. Behavioral studies demonstrate that p11 knockout mice are insensitive to the antidepressant actions of BDNF. Taken together, our data demonstrate that p11 levels are regulated by BDNF in vitro and in vivo and that the antidepressant-like effect of BDNF in two well-established behavioral models requires p11. These data support a role for p11 in the antidepressant activity of neurotrophins.

PDZ protein mediated activity-dependent LTP/LTD developmental switch at rat retinocollicular synapses

The insertion of amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) receptors into the plasma membrane and removal via internalization are essential for regulating synaptic strength, which underlies the basic mechanism of learning and memory. The retinocollicular pathway undergoes synaptic refinement during development and shows a wide variety of long-term synaptic changes; however, still little is known about its underlying molecular regulation. Here we report a rapid developmental long-term potentiation (LTP)/long-term depression (LTD) switch and its intracellular mechanism at the rat retinocollicular pathway from postnatal day 5 (P5) to P14. Before P9, neurons always exhibited LTP, whereas LTD was observed only after P10. Blockade of GluR2/3-glutamate receptor-interacting protein (GRIP)/AMPA-receptor-binding protein (ABP)/protein interacting with C kinase 1 (PICK1) interactions with pep2-SVKI could sustain the LTP after P10. This suggests that the LTP/LTD switch relied on PDZ protein activities. Selective interruption of GluR2/3-PICK1 binding by pep2-EVKI blocked the long-lasting effects of both LTP and LTD, suggesting a role for PICK1 in the maintenance of long-term synaptic plasticity. Interestingly, synaptic expression of GRIP increased more than twofold from P7 to P11, whereas ABP and PICK1 expression levels remained stable. Blockade of spontaneous retinal input suppressed this increase and abolished the LTP/LTD switch. These results suggest that the increased GRIP synaptic expression may be a key regulatory factor in mediating the activity-dependent developmental LTP/LTD switch, whereas PICK1 may be required for both LTP and LTD to maintain their long-term effects.

Polymorphisms in predicted microRNA binding sites in integrin genes and breast cancer- ITGB4 as prognostic marker

p11 (S100A10) is a key regulator of depression-like behaviors and antidepressant drug response in rodent models. Recent studies suggest that p11 mediates the behavioral antidepressant action of brain-derived neurotrophic factor (BDNF) in rodents. BDNF improves neural plasticity, which is linked to the cellular actions of antidepressant drugs. In the present study, we investigated whether p11 regulated BDNF action on neural plasticity in vitro.We generated primary hippocampal cultures. p11 expression, total dendritic length, and spine density were investigated under toxic conditions induced by B27 deprivation, which causes hippocampal cell death.B27 deprivation significantly decreased p11 expression. Treatment with BDNF significantly prevented the B27 deprivation-induced decrease in p11 levels in a concentration-dependent manner, whereas these concentrations had no effect on control cultures. B27 deprivation significantly reduced the total length of hippocampal dendrites and spine density. BDNF increased the total dendritic length and spine density in conditions with or without B27. Furthermore, p11 knockdown through small interfering RNA (siRNA) transfection blocked these effects. The overexpression of p11 in B27-deprived cells increased the total dendritic length and spine density, and treatment with BDNF potentiated these effects.This study should be confirmed in animal models of depression.Taken together, our data suggest that BDNF-induced improvement in neural plasticity may depend on the regulation of p11 in hippocampal cells with B27 deprivation. These results provide evidence to strengthen the theoretical basis of a role for p11 in BDNF-induced antidepressant action.

P11 is up-regulated in the forebrain of stressed rats by glucocorticoid acting via two specific glucocorticoid response elements in the p11 promoter

Posttraumatic stress disorder (PTSD) is one of the most common psychiatric disorders. Despite the extensive study of the neurobiological correlates of this disorder, the underlying mechanisms of PTSD are still poorly understood. Recently, a study demonstrated that dexamethasone (Dex), a synthetic glucocorticoid, can up-regulate p11, known as S100A10-protein which is down-regulated in patients with depression, (Yao et al., 1999; Huang et al., 2003) a common comorbid disorder in PTSD. These observations led to our hypothesis that traumatic stress may alter expression of p11 mediated through a glucocorticoid receptor. Here, we demonstrate that inescapable tail shock increased both prefrontal cortical p11 mRNA levels and plasma corticosterone levels in rats. We also found that Dex up-regulated p11 expression in SH-SY5Y cells through glucocorticoid response elements (GREs) within the p11 promoter. This response was attenuated by either RU486, a glucocorticoid receptor (GR) antagonist or mutating two of three glucocorticoid response elements (GRE2 and GRE3) in the p11 promoter. Finally, we showed that p11 mRNA levels were increased in postmortem prefrontal cortical tissue (area 46) of patients with PTSD. The data obtained from our work in a rat model of inescapable tail shock, a p11-transfected cell line and postmortem brain tissue from PTSD patients outline a possible mechanism by which p11 is regulated by glucocorticoids elevated by traumatic stress.

Alterations in Expression of p11 and SERT in Mucosal Biopsy Specimens of Patients With Irritable Bowel Syndrome

The pathophysiology of irritable bowel syndrome (IBS) remains enigmatic; abnormalities in serotonin metabolism have been implicated. Two proteins that influence the function of serotonin and serotonergic receptors are serotonin transporter protein (SERT or soluble carrier protein, SLC6A4) and p11 (S-100A10, or calpactin I light chain). Both proteins are reported to be associated with depression-like states, a frequent comorbid condition in IBS. We explored the hypothesis that expression of these 2 proteins in colonic and rectal mucosa is abnormal in patients with IBS as compared with healthy controls. Messenger RNA (mRNA) expression of SLC6A4 and p11 was measured in sigmoid and rectal mucosal biopsy specimens. Genotype of the promoter for SLC6A4 was also assessed in all participants. Validation studies explored reproducibility of 2 biopsy specimens taken from the same region and biopsy specimens taken an average of approximately 3 months apart. We found normal colonic mucosal expression of SLC6A4 in diarrhea (IBS-D)- or constipation-predominant IBS (IBS-C). On the other hand, p11 expression was increased in IBS. No significant effect on p11 mRNA expression in sigmoid colon or rectum was noted from antidepressant treatment in any of the analyzed subgroups. Colonic mucosal expression of SLC6A4 in IBS is normal. Given that overexpression of p11 can increase serotonergic receptor functions (eg, 5-HT(1B) receptors), these data support the need for further study of the interaction between p11 expression in health and disease and its role in the therapeutic response to serotonergic agents, including antidepressants.

Glutathione S-transferase P1-1 expression modulates sensitivity of human kidney 293 cells to photodynamic therapy with hypericin

Photodynamic therapy (PDT) relies on light-dependent, tissue-targeted, oxidative stress in tumors that have accumulated a photosensitizing drug. Glutathione S-transferases (GSTs) are often up-regulated in tumors and they modulate oxidative stress by several isoform-dependent mechanisms. GSTs, therefore, are potential confounding factors in PDT. Therefore, we examined this possibility in human kidney 293 cells transfected with a plasmid encoding either green fluorescent protein alone (pIRES-GFP) or both GFP and GSTP1-1 (pIRES-GFP-GSTP). Cells were cultured and treated with light alone, the sensitizer hypericin (HYP) alone, or light and HYP. Cells harboring pIRES-GFP-GSTP exhibited a modest 2-fold increase in GSTP1-1 expression over control cells. On the basis of flow cytometry and microscopy, the light-dependent toxicity of HYP was reduced in cells over-expressing GSTP1-1. Paradoxically, the decreased toxicity in the cells with GSTP1-1 over-expression occurred concomitantly with a modest ∼2-fold increase in cellular uptake of the drug. Immunoprecipitation of HYP and Western analysis indicated that GSTP1-1 is a major intracellular-binding site for HYP. These results are the first to demonstrate GST expression as a confounding variable of photodynamic therapy. Further, a high-affinity GST inhibitor reversed the GSTP1-1-dependent resistance, suggesting the possible utility of pharmacological strategies to optimize PDT.