Fate-mapping of erythropoietin-producing cells in mouse models of hypoxaemia and renal tissue remodelling reveals repeated recruitment and persistent functionality

Aim

Fibroblast‐like renal erythropoietin (Epo) producing (REP) cells of the corticomedullary border region “sense” a decrease in blood oxygen content following anaemia or hypoxaemia. Burst‐like transcription of Epo during tissue hypoxia is transient and is lost during fibrotic tissue remodelling, as observed in chronic kidney disease. The reason for this loss of Epo expression is under debate. Therefore, we tested the hypothesis that REP cell migration, loss and/or differentiation may cause Epo inhibition.

Methods

Using a reporter mouse that allows permanent labelling of active REP cells at any given time point, we analysed the spatiotemporal fate of REP cells following their initial hypoxic recruitment in models of hypoxaemia and renal tissue remodelling.

Results

In long‐term tracing experiments, tagged REP reporter cells neither died, proliferated, migrated nor transdifferentiated into myofibroblasts. Approximately 60% of tagged cells re‐expressed Epo upon a second hypoxic stimulus. In an unilateral model of tissue remodelling, tagged cells proliferated and ceased to produce Epo before a detectable increase in myofibroblast markers. Treatment with a hypoxia‐inducible factor (HIF) stabilizing agent (FG‐4592/roxadustat) re‐induced Epo expression in the previously active REP cells of the damaged kidney to a similar extent as in the contralateral healthy kidney.

Conclusions

Rather than cell death or differentiation, these results suggest cell‐intrinsic transient inhibition of Epo transcription: following long‐term dormancy, REP cells can repeatedly be recruited by tissue hypoxia, and during myofibrotic tissue remodelling, dormant REP cells are efficiently rescued by a pharmaceutic HIF stabilizer, demonstrating persistent REP cell functionality even during phases of Epo suppression.

Neurogenic and pericytic plasticity of conditionally immortalized cells derived from renal erythropoietin-producing cells

In adult mammals, the kidney is the main source of circulating erythropoietin (Epo), the master regulator of erythropoiesis. In vivo data in mice demonstrated multiple subtypes of interstitial renal Epo‐producing (REP) cells. To analyze the differentiation plasticity of fibroblastoid REP cells, we used a transgenic REP cell reporter mouse model to generate conditionally immortalized REP‐derived (REPD) cell lines. Under nonpermissive conditions, REPD cells ceased from proliferation and acquired a stem cell‐like state, with strongly enhanced hypoxia‐inducible factor 2 (HIF‐2α), stem cell antigen 1 (SCA‐1), and CD133 expression, but also enhanced alpha‐smooth muscle actin (αSMA) expression, indicating myofibroblastic signaling. These cells maintained the “on‐off” nature of Epo expression observed in REP cells in vivo, whereas other HIF target genes showed a more permanent regulation. Like REP cells in vivo, REPD cells cultured in vitro generated long tunneling nanotubes (TNTs) that aligned with endothelial vascular structures, were densely packed with mitochondria and became more numerous under hypoxic conditions. Although inhibition of mitochondrial oxygen consumption blunted HIF signaling, removal of the TNTs did not affect or even enhance the expression of HIF target genes. Apart from pericytes, REPD cells readily differentiated into neuroglia but not adipogenic, chondrogenic, or osteogenic lineages, consistent with a neuronal origin of at least a subpopulation of REP cells. In summary, these results suggest an unprecedented combination of differentiation features of this unique cell type.

Gender differences in facial emotion recognition in persons with chronic schizophrenia

Background

The aim of the present study was to investigate possible sex differences in the recognition of facial expressions of emotion and to investigate the pattern of classification errors in schizophrenic males and females. Such an approach provides an opportunity to inspect the degree to which males and females differ in perceiving and interpreting the different emotions displayed to them and to analyze which emotions are most susceptible to recognition errors.

Methods

Fifty six chronically hospitalized schizophrenic patients (38 men and 18 women) completed the Penn Emotion Recognition Test (ER40), a computerized emotion discrimination test presenting 40 color photographs of evoked happy, sad, anger, fear expressions and neutral expressions balanced for poser gender and ethnicity.

Results

We found a significant sex difference in the patterns of error rates in the Penn Emotion Recognition Test. Neutral faces were more commonly mistaken as angry in schizophrenic men, whereas schizophrenic women misinterpreted neutral faces more frequently as sad. Moreover, female faces were better recognized overall, but fear was better recognized in same gender photographs, whereas anger was better recognized in different gender photographs.

Conclusions

The findings of the present study lend support to the notion that sex differences in aggressive behavior could be related to a cognitive style characterized by hostile attributions to neutral faces in schizophrenic men.

The neuronal oxygen-sensing pathway controls postnatal vascularization of the murine brain

The contribution of neurons to growth and refinement of the microvasculature during postnatal brain development is only partially understood. Tissue hypoxia is the physiologic stimulus for angiogenesis by enhancing angiogenic mediators partly through activation of hypoxia-inducible factors (HIFs). Hence, we investigated the HIF oxygen-sensing pathway in postmitotic neurons for physiologic angiogenesis in the murine forebrain during postnatal development by using mice lacking the HIF suppressing enzyme prolyl-4-hydroxylase domain (PHD)2 and/or HIF-1/2α in postmitotic neurons. Perinatal activation or inactivation of the HIF pathway in neurons inversely modulated brain vascularization, including endothelial cell number and proliferation, density of total and perfused microvessels, and vascular branching. Accordingly, several angiogenesis-related genes were up-regulated in vivo and in primary neurons derived from PHD2-deficient mice. Among them, only VEGF and adrenomedullin (Adm) promoted angiogenic sprouting of brain endothelial cells. VEGF and Adm additively enhanced endothelial sprouting through activation of multiple pathways. PHD2 deficiency in neurons caused HIF-α stabilization and increased VEGF mRNA levels not only in neurons but unexpectedly also in astrocytes, suggesting a new mechanism of neuron-to-astrocyte signaling. Collectively, our results identify the PHD-HIF pathway in neurons as an important determinant for vascularization of the brain during postnatal development.-Nasyrov, E., Nolan, K. A., Wenger, R. H., Marti, H. H., Kunze, R. The neuronal oxygen-sensing pathway controls postnatal vascularization of the murine brain.

Improvement in mismatch negativity generation during d-serine treatment in schizophrenia: Correlation with symptoms

BACKGROUND

Deficits in N-methyl-d-aspartate-type (NMDAR) function contribute to symptoms and cognitive dysfunction in schizophrenia. The efficacy of NMDAR agonists in the treatment of persistent symptoms of schizophrenia has been variable, potentially reflecting limitations in functional target engagement. We recently demonstrated significant improvement in auditory mismatch negativity (MMN) with once-weekly treatment with d-serine, a naturally occurring NMDAR glycine-site agonist. This study investigates effects of continuous (daily) NMDAR agonists in schizophrenia/schizoaffective disorder.

METHODS

Primary analysis was on MMN after double-blind crossover (60mg/kg/d, n=16, 6weeks) treatment with d-serine/placebo. Secondary measures included clinical symptoms, neurocognition, and the effects of open-label (30-120mg/kg/d, n=21) d-serine and bitopertin/placebo (10mg, n=29), a glycine transport inhibitor.

RESULTS

Double-blind d-serine treatment led to significant improvement in MMN frequency (p=0.001, d=2.3) generation and clinical symptoms (p=0.023, d=0.80). MMN frequency correlated significantly with change in symptoms (r=-0.63, p=0.002) following co-variation for treatment type. d-Serine treatment led to a significant, large effect size increase vs. placebo in evoked α-power in response to standards (p=0.036, d=0.81), appearing to normalize evoked α power relative to previous findings with controls. While similar results were seen with open-label d-serine, no significant effects of bitopertin were observed for symptoms or MMN.

CONCLUSIONS

These findings represent the first randomized double-blind placebo-controlled study with 60mg/kg d-serine in schizophrenia, and are consistent with meta-analyses showing significant effects of d-serine in schizophrenia. Results overall support suggest that MMN may have negative, as well as positive, predictive value in predicting efficacy of novel compounds.

CLINICAL TRIALS REGISTRATION

Clinicaltrials.gov: NCT00322023/NCT00817336 (d-serine); NCT01116830 (bitopertin).

Hypoxia: from basic mechanisms to therapeutics - a meeting report on the Keystone and HypoxiaNet Symposium

In May 2015, the hypoxia research community came together at the largest meeting in this field to date, to present and discuss their most recent and mainly unpublished findings. This meeting report aims to summarize the data presented at this conference, which were broadly separated into the areas of the cellular hypoxic response, the relevance of the hypoxic response in health and disease, and the development of new therapeutics targeting the hypoxic response.

Respite-retreat for dementia caregivers: A demonstration

A one-day retreat focusing on spiritual renewal for caregivers was offered in conjunction with a concurrent dementia day care program. Postretreat questionnaire responses indicated positive attitudes overall toward the spiritual retreat, but many caregivers expressed a desire for greater informational content and more time for interaction with other caregivers. All were satisfied with the level of care patients received in the day program. Although there was no significant change in mean level of depression in caregivers following the retreat, the concurrent respite-retreat experience appeared to motivate several caregivers to try a group support service for thefirst time.

REST is a hypoxia-responsive transcriptional repressor

Cellular exposure to hypoxia results in altered gene expression in a range of physiologic and pathophysiologic states. Discrete cohorts of genes can be either up- or down-regulated in response to hypoxia. While the Hypoxia-Inducible Factor (HIF) is the primary driver of hypoxia-induced adaptive gene expression, less is known about the signalling mechanisms regulating hypoxia-dependent gene repression. Using RNA-seq, we demonstrate that equivalent numbers of genes are induced and repressed in human embryonic kidney (HEK293) cells. We demonstrate that nuclear localization of the Repressor Element 1-Silencing Transcription factor (REST) is induced in hypoxia and that REST is responsible for regulating approximately 20% of the hypoxia-repressed genes. Using chromatin immunoprecipitation assays we demonstrate that REST-dependent gene repression is at least in part mediated by direct binding to the promoters of target genes. Based on these data, we propose that REST is a key mediator of gene repression in hypoxia.

What can the study of first impressions tell us about attitudinal ambivalence and paranoia in schizophrenia?

Although social cognition deficits have been associated with schizophrenia, social trait judgments - or first impressions - have rarely been studied. These first impressions, formed immediately after looking at a person's face, have significant social consequences. Eighty-one individuals with schizophrenia or schizoaffective disorder and 62 control subjects rated 30 neutral faces on 10 positive or negative traits: attractive, mean, trustworthy, intelligent, dominant, fun, sociable, aggressive, emotionally stable and weird. Compared to controls, patients gave higher ratings for positive traits as well as for negative traits. Patients also demonstrated more ambivalence in their ratings. Patients who were exhibiting paranoid symptoms assigned higher intensity ratings for positive social traits than non-paranoid patients. Social trait ratings were negatively correlated with everyday problem solving skills in patients. Although patients appeared to form impressions of others in a manner similar to controls, they tended to assign higher scores for both positive and negative traits. This may help explain the social deficits observed in schizophrenia: first impressions of higher degree are harder to correct, and ambivalent attitudes may impair the motivation to interact with others. Consistent with research on paranoia and self-esteem, actively-paranoid patients' positive social traits judgments were of higher intensity than non-paranoid patients'.

Implicit emotion perception in schizophrenia

Explicit but not implicit facial emotion perception has been shown to be impaired in schizophrenia. In this study, we used newly developed technology in social neuroscience to examine implicit emotion processing. It has been shown that when people look at faces, they automatically infer social traits, and these trait judgments rely heavily on facial features and subtle emotion expressions even with neutral faces. Eighty-one individuals with schizophrenia or schizoaffective disorder and 62 control subjects completed a computer task with 30 well-characterized neutral faces. They rated each face on 10 trait judgments: attractive, mean, trustworthy, intelligent, dominant, fun, sociable, aggressive, emotionally stable and weird. The degree to which trait ratings were predicted by objectively-measured subtle emotion expressions served as a measure of implicit emotion processing. Explicit emotion recognition was also examined. Trait ratings were significantly predicted by subtle facial emotional expressions in controls and patients. However, impairment in the implicit emotion perception of fear, happiness, anger and surprise was found in patients. Moreover, these deficits were associated with poorer everyday problem-solving skills and were relatively independent of explicit emotion recognition. Implicit emotion processing is impaired in patients with schizophrenia or schizoaffective disorder. Deficits in implicit and explicit emotion perception independently contribute to the patients' poor daily life skills. More research is needed to fully understand the role of implicit and explicit processes in the functional deficits of patients, in order to develop targeted and useful remediation interventions.

Induction of long noncoding RNA MALAT1 in hypoxic mice

Long thought to be “junk DNA”, in recent years it has become clear that a substantial fraction of intergenic genomic DNA is actually transcribed, forming long noncoding RNA (lncRNA). Like mRNA, lncRNA can also be spliced, capped, and polyadenylated, affecting a multitude of biological processes. While the molecular mechanisms underlying the function of lncRNAs have just begun to be elucidated, the conditional regulation of lncRNAs remains largely unexplored. In genome-wide studies our group and others recently found hypoxic transcriptional induction of a subset of lncRNAs, whereof nuclear-enriched abundant/autosomal transcript 1 (NEAT1) and metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) appear to be the lncRNAs most ubiquitously and most strongly induced by hypoxia in cultured cells. Hypoxia-inducible factor (HIF)-2 rather than HIF-1 seems to be the preferred transcriptional activator of these lncRNAs. For the first time, we also found strong induction primarily of MALAT1 in organs of mice exposed to inspiratory hypoxia. Most abundant hypoxic levels of MALAT1 lncRNA were found in kidney and testis. In situ hybridization revealed that the hypoxic induction in the kidney was confined to proximal rather than distal tubular epithelial cells. Direct oxygen-dependent regulation of MALAT1 lncRNA was confirmed using isolated primary kidney epithelial cells. In summary, high expression levels and acute, profound hypoxic induction of MALAT1 suggest a hitherto unrecognized role of this lncRNA in renal proximal tubular function.

Paricalcitol protects against TGF-β1-induced fibrotic responses in hypoxia and stabilises HIF-α in renal epithelia

Epithelial injury and tubulointerstitial fibrosis (TIF) within a hypoxic microenvironment are associated with progressive loss of renal function in chronic kidney disease [CKD]. Transforming growth factor beta-1 (TGF-β1) is an important mediator of renal fibrosis. Growing evidence suggests that Vitamin D [1,25-(OH)2D] and its analogues may have a renoprotective effect in CKD. Here we examined the protective effect of the vitamin D analogue paricalcitol [PC; 19-nor-1α,3β,25-trihydroxy-9,10-secoergosta-5(Z),7(E) 22(E)-triene] on the responses of human renal epithelial cells to TGF-β1. PC attenuated TGF-β1-induced Smad 2 phosphorylation and upregulation of the Notch ligand Jagged-1, α-smooth muscle actin and thrombospondin-1 and prevented the TGF-β1-mediated loss of E-Cadherin. To mimic the hypoxic milieu of CKD we cultured renal epithelial cells in hypoxia [1% O2] and observed similar attenuation by PC of TGF-β1-induced fibrotic responses. Furthermore, in cells cultured in normoxia [21% O2], PC induced an accumulation of hypoxia-inducible transcription factors (HIF) 1α and HIF-2α in a time and concentration [1 µM-2 µM] dependent manner. Here, PC-induced HIF stabilisation was dependent on activation of the PI-3Kinase pathway. This is the first study to demonstrate regulation of the HIF pathway by PC which may have importance in the mechanism underlying renoprotection by PC.

The two common polymorphic forms of human NRH-quinone oxidoreductase 2 (NQO2) have different biochemical properties

There are two common forms of NRH-quinone oxidoreductase 2 (NQO2) in the human population resulting from SNP rs1143684. One has phenylalanine at position 47 (NQO2-F47) and the other leucine (NQO2-L47). Using recombinant proteins, we show that these variants have similar steady state kinetic parameters, although NQO2-L47 has a slightly lower specificity constant. NQO2-L47 is less stable towards proteolytic digestion and thermal denaturation than NQO2-F47. Both forms are inhibited by resveratrol, but NQO2-F47 shows negative cooperativity with this inhibitor. Thus these data demonstrate, for the first time, clear biochemical differences between the variants which help explain previous biomedical and epidemiological findings.

Lipoxins attenuate renal fibrosis by inducing let-7c and suppressing TGFβR1

Lipoxins, which are endogenously produced lipid mediators, promote the resolution of inflammation, and may inhibit fibrosis, suggesting a possible role in modulating renal disease. Here, lipoxin A4 (LXA4) attenuated TGF-β1-induced expression of fibronectin, N-cadherin, thrombospondin, and the notch ligand jagged-1 in cultured human proximal tubular epithelial (HK-2) cells through a mechanism involving upregulation of the microRNA let-7c. Conversely, TGF-β1 suppressed expression of let-7c. In cells pretreated with LXA4, upregulation of let-7c persisted despite subsequent stimulation with TGF-β1. In the unilateral ureteral obstruction model of renal fibrosis, let-7c upregulation was induced by administering an LXA4 analog. Bioinformatic analysis suggested that targets of let-7c include several members of the TGF-β1 signaling pathway, including the TGF-β receptor type 1. Consistent with this, LXA4-induced upregulation of let-7c inhibited both the expression of TGF-β receptor type 1 and the response to TGF-β1. Overexpression of let-7c mimicked the antifibrotic effects of LXA4 in renal epithelia; conversely, anti-miR directed against let-7c attenuated the effects of LXA4. Finally, we observed that several let-7c target genes were upregulated in fibrotic human renal biopsies compared with controls. In conclusion, these results suggest that LXA4-mediated upregulation of let-7c suppresses TGF-β1-induced fibrosis and that expression of let-7c targets is dysregulated in human renal fibrosis.

In silico screening reveals structurally diverse, nanomolar inhibitors of NQO2 that are functionally active in cells and can modulate NF-κB signaling

The National Cancer Institute chemical database has been screened using in silico docking to identify novel nanomolar inhibitors of NRH:quinone oxidoreductase 2 (NQO2). The inhibitors identified from the screen exhibit a diverse range of scaffolds and the structure of one of the inhibitors, NSC13000 cocrystalized with NQO2, has been solved. This has been used to aid the generation of a structure-activity relationship between the computationally derived binding affinity and experimentally measured enzyme inhibitory potency. Many of the compounds are functionally active as inhibitors of NQO2 in cells at nontoxic concentrations. To show this, advantage was taken of the NQO2-mediated toxicity of the chemotherapeutic drug CB1954. The toxicity of this drug is substantially reduced when the function of NQO2 is inhibited, and many of the compounds achieve this in cells at nanomolar concentrations. The NQO2 inhibitors also attenuated TNFα-mediated, NF-кB-driven transcriptional activity. The link between NQO2 and the regulation of NF-кB was confirmed by using short interfering RNA to NQO2 and by the observation that NRH, the cofactor for NQO2 enzyme activity, could regulate NF-кB activity in an NQO2-dependent manner. NF-кB is a potential therapeutic target and this study reveals an underlying mechanism that may be usable for developing new anticancer drugs.

Self-report and laboratory measures of impulsivity in patients with schizophrenia or schizoaffective disorder and healthy controls

This study examined self-reported impulsivity and aggression and performance on the stop-signal task in patients with schizophrenia or schizoaffective disorder and healthy volunteers. Compared to controls, patients had higher scores on interview and questionnaire measures of impulsivity and aggression and showed increased stop-signal reaction time and greater response variability. These findings are consistent with a specific impairment in response inhibition in schizophrenia.

Abstract 1713: Mechanisms of resistance to platinum based drugs uncovered by protection caused by substituted coumarins

Disruption of p53 can have a profound effect on cellular sensitivity to Platinum-based drugs. Inhibition of NQO1 by dicoumarol and other substituted coumarins can target p53 for degradation. Thus, we tested the ability of NQO1 inhibitors to protect HCT116 cells (containing wild type p53) against the cytotoxic effects of cisplatin. All the NQO1 inhibitors protect cells against the damaging effects of cisplatin (see the table for representative data for one of the inhibitors, AS3). Protection was also seen in a second cell line with wild type p53 (RT112 bladder carcinoma cells). To confirm p53 dependence, experiments were carried out using cells with mutant (MDA231) or null (HCT116 -/-) p53. Surprisingly, the coumarin-based agents also protected these cells against cisplatin-induced damage. In addition, these observations were not dependent on NQO1, since MDA231 cells, with negligible NQO1, and cells overexpressing NQO1 (MDA321-DTD) were similarly protected. Protection is also observed for oxaliplatin but, interestingly, there is no protection against etoposide toxicity.

Cell cycle analysis of HCT116 cells treated with cisplatin show that, 24 hours after treatment, cells are blocked in G2. When cells are given the dicoumarol analogues at the same time as the cisplatin, no cell cycle delay is observed. Further, analysis of apoptosis mediators shows that treatment with AS3 inhibits oxaliplatin induction of Bak and reduces caspase-3 activity. Understanding the mechanism by which treatment with the dicoumarol analogues can cause resistance to cisplatin could reveal new methods for potentially overcoming resistance to platinum-based drugs in the clinic.

Abstract 3713: Inhibition of NQO2 by imidozoacridinones, including C1311 (Symadex, NSC645809): Implications for their mechanism of action

INTRODUCTION: Imidazoacridinones (IAs) have well documented anti-tumour activity in vitro and in vivo. They are thought to act as intercalating agents and inhibitors of topoisomerase II. More recently C1311 and other IAs have been shown to act as inhibitors of receptor tyrosine kinases such as FLT3 (J Clin Oncol 2008. Vol 26(15S) 2576). We have recently demonstrated that a structurally related series of triazoloacridinones can act as potent inhibitors of the oxidoreductases NQO1 and NQO2 (Bioorg Med Chem, 2009. In Press). Consequently, we conducted a computational substructure screen of the NCI chemical database to identify compounds with an IA scaffold. Here we describe these compounds, as novel inhibitors of NQO2, with low nanomolar potency. Moreover, some of these agents are up to 50-fold more efficient than the standard inhibitor, resveratrol.

EXPERIMENTAL: Compounds were evaluated spectrophotometrically for their ability to inhibit human NQO2 using NRH and DCPIP as co-substrates. Inhibitory potency (IC50) was related to computational binding affinity in order to derive potential structure/activity relationships. Toxicity was assessed in HCT116 cells (measured as the concentration required to reduce proliferation by 50%) using the MTT assay. The capacity of the compounds to interact with DNA was measured by changes in DNA melting temperature. Intercalative properties were confirmed by ethidium bromide displacement in SDS-PAGE gel electrophoresis

RESULTS: Seventeen compounds were evaluated for inhibitory potency which ranged from 6 to 1000nM. IC50 values were correlated with computationally derived binding affinities with a correlation coefficient of 0.93. However, the 200 fold difference in NQO2 inhibitory potency was not associated with any major change in toxicity which ranged from 460 to 3000nM. All compounds (at 10μM) were able to increase the melting temperature of calf thymus DNA in low salt solution. Changes in Tm ranged from 4.5 to 9oC and correlated well with ethidium bromide displacement. Though, as previously reported for IAs (Biochem Pharma, 2002. Vol 63, 1653), no obvious relationship could be determined between toxicity and Tm or the ability to displace ethidium bromide from DNA.

CONCLUSION: We have identified IAs as novel inhibitors of NQO2, with some in the series being the most potent inhibitors yet reported. Therefore, these agents could have applications in processes, such as inflammation, where NQO2 may be important. Furthermore, one of the IAs in the series is C1311 (IC50 = 148nM), an agent currently in clinical trial. It has been reported that tyrosine kinase inhibitors, such as imatinib, can also interact with NQO2 (BMC Struct Biol, 2009. Vol 9(7) 1472) and this may compromise drug action. Hence, when reviewing the activity of C1311, the cellular content of NQO2 should be considered since drug/enzyme interactions could influence overall activity.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 3713.

Adolescent cannabis use, psychosis and catechol-O-methyltransferase genotype in African Americans and Caucasians

Cannabis has been reported as a likely risk factor for the development of psychosis, and a gene × environment interaction with the catechol-O-methyltransferase (COMT) gene has been proposed. Moreover, COMT has been separately linked to affective symptoms in psychosis. Despite a high rate of cannabis abuse and affective symptoms in African Americans, no studies exploring a relationship between COMT and psychosis in this group have been reported. An existing database of psychotic patients with and without adolescent cannabis use/affective symptoms was examined, and chi-square analyses for independence were applied separately for both Caucasians and African-Americans to examine genotype associations with adolescent cannabis use and affective symptoms (past or present). The two subject groups did not differ with respect to the prevalence of adolescent cannabis abuse or presence of affective symptoms. Further study is needed, with non-psychotic controls and larger samples.

Staff and patient views of the reasons for aggressive incidents: a prospective, incident-based study

Aggression is a serious problem in psychiatric hospitals. It is not clear whether reasons for aggression guide which therapeutic interventions are selected. Aggression was monitored in participants in a randomized clinical trial of the antiaggressive efficacy of adjunctive valproate in patients with schizophrenia. The Overt Aggression Scale was used to record aggression type and severity, reasons given by patients and staff, and interventions delivered. Forty two patients caused 317 aggressive incidents. Patients reported more often than staff that aggression was provoked by external factors (e.g., interpersonal conflict, limit-setting). Staff cited internal factors (e.g., psychotic symptoms, tension) more often than patients. Interventions administered were related to type and severity of aggression but not to either staff or patients' reasons. Responses to aggressive events do not take causes into account. It is possible that consideration of the reasons for the aggressive behavior might yield more targeted interventions.

Analysis of a promoter polymorphism in the SMDF neuregulin 1 isoform in Schizophrenia

BACKGROUND/AIMS

Neuregulin 1 (NRG1) is a positional candidate gene in schizophrenia (SZ). Two major susceptibility loci in the NRG1 gene approximately one million nucleotides apart have been identified in genetic studies. Several candidate functional allelic variants have been described that might be involved in disease susceptibility. However, the findings are still preliminary. We recently mapped active promoters and other regulatory domains in several SZ and bipolar disorder (BD) candidate genes using ChIP-chip (chromatin immunoprecipitation hybridized to microarrays). One was the promoter for the NRG1 isoform, SMDF, which maps to the 3' end of the gene complex. Analysis of the SNP database revealed several polymorphisms within the approximate borders of the region immunoprecipitated in our ChIP-chip experiments, one of which is rs7825588.

METHODS

This SNP was analyzed in patients with SZ and BD and its effect on promoter function was assessed by electromobility gel shift assays and luciferase reporter constructs.

RESULTS

A significant increase in homozygosity for the minor allele was found in patients with SZ (genotype distribution chi(2) = 7.32, p = 0.03) but not in BD (genotype distribution chi(2) = 0.52, p = 0.77). Molecular studies demonstrated modest, but statistically significant allele-specific differences in protein binding and promoter function.

CONCLUSION

The findings suggest that homozygosity for rs725588 could be a risk genotype for SZ.

Methodological structure for aggression research

Kendler's seminal essay listed 8 major propositions outlining a philosophical framework for the entire field of psychiatry [Kendler (American Journal of Psychiatry 162:433-440, 2005)]. These propositions have grounded psychiatric research on a coherent conceptual basis. The field of aggression research needs a general conceptual framework that would help us to integrate the contributions of neurobiology, sociology, criminology, and other areas. All of Kendler's propositions are generally relevant in this respect. The aim of the current article is to develop specific applications of four of Kendler's propositions for aggression research. These four propositions are: "Psychiatry is irrevocably grounded in mental, first-person experiences", "Psychiatric disorders are etiologically complex, and we can expect no more "spirochete-like" discoveries that will explain their origin in simple terms", "Explanatory pluralism is preferable to monistic explanatory approaches, especially biological reductionism", and "Acceptance of Patchy Reductionism".

Public-academic partnerships: integrating state psychiatric hospital treatment and clinical research

Collaboration between state clinical treatment services and academic research is fertile ground for clinical research opportunities. Such joint initiatives require careful planning, including provisions for joint training, integration of research staff into clinical activities, and integration of clinical treatment staff into research activities. The authors describe the planning and development of a 24-bed research unit at the Nathan S. Kline Institute for Psychiatric Research, colocated on the same campus as Rockland Psychiatric Center, each of which is an independent facility operated by the New York State Office of Mental Health.

Reducing inpatient aggression: does paying attention pay off?

OBJECTIVE

Inpatient aggression is poorly documented in official records. Video technology can improve detection, but is labor-intensive and costly. We examined the effectiveness of interventions to improve reporting on a secure inpatient research unit equipped with audio/video surveillance.

METHOD

Systematic review of all video recorded during a six-week period in 2000 revealed that official documentation omitted 16/71 aggressive incidents (23%). Subsequent interventions to improve reporting involved therapy aides, whose jobs entail continuous direct contact with patients. We reviewed the corresponding period in 2005 to investigate changes in aggression and reporting.

RESULTS

Although the number of aggressive incidents did not change significantly, reporting improved: 59/62 (95%) events detected in 2005 had been reported. Physical aggression decreased and verbal aggression increased.

CONCLUSIONS

Improved reporting may have the unanticipated benefit of reducing physical aggression, perhaps by fostering recognition of and intervention in events that might otherwise escalate into more serious aggression.

Differential effect of catechol-O-methyltransferase Val158Met genotype on emotional recognition abilities in healthy men and women

The catechol-O-methyltransferase (COMT) Val158Met polymorphism modulates executive functions and working memory and recent neuroimaging studies implicate an association with emotional processing. We examined the relationship between the COMT Val158Met polymorphism and facial emotion recognition and differentiation in 100 healthy individuals. Compared to Met homozygosity, Val homozygosity was associated with better and faster recognition of negative facial expressions such as anger and sad. Our study provides evidence for a possible influence of the COMT polymorphism on emotion recognition abilities in healthy subjects. Additional research is needed to further define the neurocognitive phenotypes associated with COMT polymorphisms.

Positive association of schizophrenia to JARID2 gene

Dysbindin (DTNBP1) is a positional candidate gene for 6p22.3-linked schizophrenia (SZ). However, so far, no disease-causing alleles have been identified. DTNBP1 is immediately adjacent to JARID2, a member of the ARID (AT-rich interaction domain) family of transcription modulators. We have previously suggested that proteins which bind to AT-rich domains could play a role in SZ pathogenesis. Consequently, we explored the possibility that JARID2 itself could be a candidate gene for 6p22.3-linked SZ. We used a case control design to analyze single nucleotide polymorphisms (SNPs) and insertion/deletion variants affecting AT-rich domains in both the DTNBP1 and JARID2 genes. Three of the DTNBP1 SNPs analyzed had previously been shown to be associated with SZ. We did not detect any significant difference in allele, genotype or haplotype distribution for any of these DTNBP1 markers. However, we did detect a significant difference in allele distribution for a tetranucleotide repeat polymorphism in the JARID2 gene that affects an AT-rich domain. A significant increase in short alleles (less than 11 repeats) was found in patients with SZ (chi(2) = 7.02; P = 0.008). No other JARID2 marker displayed statistically significant allele and genotype distributions. Our findings suggest that JARID2 should be viewed as a candidate gene for 6p22.3-linked SZ.

In silico identification and biochemical characterization of novel inhibitors of NQO1

From in silico docking and COMPARE analysis, novel inhibitors of human NAD(P)H quinone oxidoreductase (NQO1) have been identified from the NCI compound database, the most potent of which has an observed IC(50) of 0.7muM. The inhibitors exhibit a diverse range of scaffolds. The ability of docking calculations to predict experimentally determined binding affinities for NQO1 is discussed, considering the influence of target flexibility and scoring function.

Analysis of polymorphisms in AT-rich domains of neuregulin 1 gene in schizophrenia

Linkage analysis and association studies have pointed to neuregulin 1 (NRG1) as the prime candidate for 8p-linked schizophrenia (SZ). However, so far, no specific functional alleles in the gene's exons, intron-exon junctions and promoters have been identified that are unequivocally associated with SZ. In this study, we analyzed several NRG1 polymorphisms that affect ATTT motifs and AT-rich regions of the gene. We have previously identified a number of such polymorphisms in the promoters of other SZ and bipolar disorder (BD) candidate genes and found positive associations to several of them. In addition, allele specific differences in the binding of brain proteins have been found for many of the polymorphisms. A case control design was used to compare allele frequencies in Caucasian and African American patients with SZ and controls. In the African American group, a significant difference was found in the allele and genotype distribution for several of the markers and haplotype blocks located in the 5'- and 3'-ends of the gene. The most significant result was obtained for rs6150532, an insertion/deletion variant in a conserved region of an intron that separates two small, alternatively spliced exons. Allele-specific and developmental differences were detected in the binding of a brain protein using newborn rat pups when probes containing the two rs6150532 alleles were used in electromobility gel shift assays. There were no significant differences in allele or genotype distribution found for any of the markers in the Caucasian sample. Although the samples size is relatively small, the findings support a role for NRG1 in SZ in African Americans and suggest that polymorphic differences in regions of the gene that recognize AT-binding proteins may be a factor in disease pathogenesis.

Aggression and psychopathology in treatment-resistant inpatients with schizophrenia and schizoaffective disorder

Positive psychotic symptoms, such as threat/"control-override" delusions or command hallucinations, have been related to aggression in patients with schizophrenia. However, retrospective data collection has hampered evaluation of the direct influence of psychopathology on aggressive behavior. In this study, we monitored aggressive behavior and psychopathology prospectively and in close temporal proximity in 157 treatment-resistant inpatients diagnosed with chronic schizophrenia or schizoaffective disorder participating in a 14-week double-blind clinical trial. Aggressive behavior was rated with the overt aggression scale (OAS). Psychopathology was assessed using the positive and negative syndrome scale (PANSS). At baseline, subjects who would be aggressive during the study had higher scores on only two PANSS items: hostility and poor impulse control. During the study PANSS positive subscale scores were significantly higher in aggressive subjects. Total PANSS scores were higher within 3 days of an aggressive incident, as were positive and general psychopathology subscale scores. However, in a smaller subsample for whom PANSS ratings were available within 3 days before aggressive incidents, only scores on the PANSS positive subscale were significantly higher. These findings in chronic, treatment resistant inpatients support the view that positive symptoms may lead to aggression.

Catechol O-methyltransferase Val158Met polymorphism in schizophrenia: differential effects of Val and Met alleles on cognitive stability and flexibility

OBJECTIVE

The catechol O-methyltransferase (COMT) Val158Met polymorphism has been associated with cognitive and behavioral phenotypes in schizophrenia. Whether COMT genotype is beneficial may depend on phenotype definition. The authors examined the effects of COMT genotype on a task that distinguishes imitation from reversal learning. They hypothesized that the Val and Met alleles would be associated with deficits in imitation learning and reversal learning, respectively.

METHOD

Twenty-six patients with schizophrenia and schizoaffective disorder completed a task requiring alternation between imitation and reversal rules.

RESULTS

Met homozygotes showed better acquisition of the imitation rule but greater deficit shifting from imitation to reversal. Val homozygotes had poorer imitation performance and slower reaction times.

CONCLUSIONS

The Met allele, by increasing tonic dopamine, may promote cognitive stability but limit cognitive flexibility.

Characteristics of assaultive behavior among psychiatric inpatients

OBJECTIVE

The purpose of this study was to assess the extent to which psychosis, disordered impulse control, and psychopathy contribute to assaults among psychiatric inpatients.

METHODS

The authors used a semistructured interview to elicit reasons for assaults from assailants and their victims on an inpatient research ward. Video monitoring provided supplemental information to confirm participants' identities and activities before and during the assault.

RESULTS

Consensus clinical ratings indicated that approximately 20 percent of the assaults in this sample were directly related to positive psychotic symptoms. Factor analysis revealed two psychosis-related factors, one related to positive psychotic symptoms and the other to psychotic confusion and disorganization, as well as a third factor that differentiated impulsive from psychopathic assaults.

CONCLUSIONS

Information obtained from interviews with assailants can reveal the underlying causes of specific assaults. This information is potentially useful in the selection of rational antiaggressive treatment strategies.

Aggressive behavior in schizophrenia is associated with the low enzyme activity COMT polymorphism: a replication study

We have previously reported that increased aggressive behavior in schizophrenic patients may be associated with a polymorphism at codon 158 of the catechol O-methyltransferase (COMT) gene that encodes a low enzyme activity variant. The finding has been replicated by one group, but not others. The discordant findings could be due to statistical errors or methodological issues in the assessment of aggressive/violent behavior. Consequently, additional studies are needed. Patients with schizophrenia (SZ) were assessed for violent behavior using the Lifetime History of Aggression (LHA) scale, an 11-item questionnaire that includes Aggression, Self-Directed Aggression, and Consequences/Antisocial Behavior subscales. DNA was genotyped for the COMT 158 polymorphism, as well as a functional polymorphism in the monoamine oxidase A (MAOA) gene promoter. Similar to our previously reported findings, a statistically significant association was found between aggressive behavior in SZ and the COMT 158 polymorphism; mean LHA scores were higher in subjects homozygous for 158Met, the low enzyme activity COMT variant (F(2,105) = 5.616, P = 0.005). Analysis of the major LHA subscales revealed that the association with 158Met was due to high scores on the Aggression, and Self-Directed Aggression subscales, but not the Consequences/Antisocial Behavior subscale. No significant association was detected for the MAOA gene alone. Our findings provide further support that COMT is a modifying gene that plays a role in determining interindividual variability in the proclivity for outward and self-directed aggressive behavior found in some schizophrenic patients.

An association between a polymorphism of the tryptophan hydroxylase gene and aggression in schizophrenia and schizoaffective disorder

Serotonergic pathways have been implicated in impulsive and aggressive behavior. Polymorphisms in the regulatory region of the serotonin transporter (5-HTT), in intron 7 of the tryptophan hydroxylase (TPH) gene and in the MAOA gene were previously reported to be associated with mood and anxiety disorders, impulsivity and aggression. In this study, we analyzed these polymorphisms in men and women with schizophrenia or schizoaffective disorder (n = 84) who met our criteria for violence (history of two or more assaults on others) or nonviolence (no history of either assaultive or threatening behavior). In males, a modest association between TPH genotype and history of violence (chi-square test = 6.703, degrees of freedom = 2, P = 0.035) was not statistically significant after correction for multiple comparisons (corrected P = 0.21). The TPH L allele was more frequent in violent males (chi-square = 5.323, degrees of freedom = 1, P = 0.021) but this difference also failed to withstand correction (corrected P = 0.126). No significant associations were found for either the 5-HTT or MAOA polymorphisms in males or females. These results tend to support previous reports by New et al. (1996; 1998) of an association between the TPH L allele and impulsive aggression in males with personality disorder, but larger studies are needed.

Suicidal behavior in patients with schizophrenia is related to COMT polymorphism

A common functional polymorphism that results in a three- to four-fold difference in catechol-O-methyltransferase (COMT) enzyme activity has been related to psychiatric disorders such as ultra-ultra rapid cycling bipolar disorder, drug abuse and alcoholism (Lachman et al., 1996a; Karayiorgou et al., 1997; Vandenbergh et al., 1997; Papolos et al., 1998; Tiihonen et al., 1999). Several studies have also reported associations between the allele encoding the low enzyme activity COMT variant (L allele) and other-directed aggression (Strous et al., 1997; Lachman et al., 1998; Kotler et al., 1999) in schizophrenic and schizoaffective patients. The current study investigated whether the COMT L allele is also associated with suicide attempts in schizophrenic and schizoaffective patients. COMT genotypes were determined and history of suicide attempts was retrospectively investigated in a Finnish sample (n = 94) and a US sample (n = 54). Significant associations were observed between COMT genotype and suicide; specifically, history of violent suicide attempts. The COMT L allele was more frequent in subjects who had attempted suicide by violent means. These associations were significant in males but not females. These findings support a common neurobiological substrate for self- and other-directed aggression, and suggest that catecholaminergic alterations may contribute to these behaviors in schizophrenic and schizoaffective patients.

Psychopathy and violent behavior among patients with schizophrenia or schizoaffective disorder

OBJECTIVE

Although a strong association between violence and psychopathy has been demonstrated in nonpsychotic forensic populations, the relationship between psychopathy and violence among patients with schizophrenia has not been thoroughly explored. Patients with and without a history of persistent violent behavior were compared for comorbidity of psychopathy and schizophrenia or schizoaffective disorder.

METHODS

Violent and nonviolent patients were identified through reviews of hospital charts and records of arrests and convictions. The Psychopathy Checklist: Screening Version was administered to 51 patients, 26 violent patients and 25 matched nonviolent patients. Analysis of variance was used as the principal statistical method for comparing violent and nonviolent groups.

RESULTS

Mean psychopathy scores were higher for violent patients than nonviolent patients. Five of the violent patients (19 percent) had scores exceeding the cutoff for psychopathy, and 13 (50 percent) scored in the possible psychopathic range. All of the nonviolent patients scored below the cutoff for possible psychopathy. Higher psychopathy scores were associated with earlier age of onset of illness and more arrests for both violent and nonviolent offenses.

CONCLUSIONS

The comorbidity of schizophrenia and psychopathy was found to be higher among violent patients than among nonviolent patients. Violent patients with schizophrenia who score high on measures of psychopathy may have a personality disorder that precedes the emergence of psychotic symptoms, or they may constitute a previously unclassified subtype of schizophrenia, characterized by early symptoms of conduct disorder symptoms and persistent violent behavior.

Incidence of the Fuld WAIS-R profile in traumatic brain injury and Parkinson's disease

The frequency of occurrence of the Fuld Profile for cholinergic deficiency was investigated in two clinical populations: inpatients who had suffered traumatic brain injury and outpatients who carried a diagnosis of Parkinson's disease. The observed incidence of positive Fuld profiles was not significantly different in the two groups, 14% in the traumatic brain injury group and 24% in the Parkinson's disease group. These findings are consistent with recent reviews of the sensitivity and specificity of the Fuld profile in various clinical and nonclinical populations. The generally low sensitivity of the Fuld profile does not support its usefulness in the differential diagnosis of dementia. However, it may serve as an indicator of cholinergic deficiency, which could be used to select patients who would be likely to respond to cholinomimetic therapies.

Association between catechol O-methyltransferase genotype and violence in schizophrenia and schizoaffective disorder

OBJECTIVE

The authors previously reported a relationship between an allele encoding the low activity variant of catechol O-methyltransferase (COMT) and aggressive behavior in schizophrenic patients. This study replicates and extends these findings by using more direct measures of violent behavior.

METHOD

Fifty-five white patients (34 men, 21 women) with DSM-IV diagnoses of schizophrenia or schizoaffective disorder were selected to form two groups (violent and nonviolent) on the basis of history of aggressive behavior. COMT genotypes were determined by restriction fragment length polymorphism analysis.

RESULTS

A significant association was found between COMT genotype and history of violent behavior. Sixty-four percent of patients homozygous for the low-activity COMT allele were violent; 80% of patients homozygous for the high-activity allele were nonviolent.

CONCLUSIONS

The gene determining the activity of an important regulatory enzyme in catecholamine inactivation is associated with violent behavior in patients with schizophrenia and schizoaffective disorder.

Ret oncogene activation in papillary thyroid carcinoma: prevalence and implication on the histological parameters

The Ret proto-oncogene is known to be rearranged in papillary carcinoma of the thyroid. The aim of this study was to investigate the in situ expression of Ret mRNA in thyroid tumors. Formalin-fixed, paraffin-embedded tissue specimens from 45 thyroid lesions were examined by in situ hybridization using manual capillary action technology (MicroProbe Staining System) and a 52-base synthetic biotinylated oligonucleotide probe complementary to the tyrosine-kinase domain of Ret proto-oncogene. The clinicopathological features of these patients with thyroid lesions also were noted. Ret was noted in 17 (43%) of 40 papillary carcinomas. In contrast, none of the three follicular carcinomas, follicular adenoma, nodular hyperplasia, and normal thyroids, showed evidence of Ret mRNA. Our results showed that, in papillary thyroid carcinoma, there is an important role of Ret activation. The Ret staining could be a useful marker for papillary carcinoma.

Absence of vascular dementia in an autopsy series from a dementia clinic

OBJECTIVE

The role of cerebrovascular disease in dementia in older people has been the subject of controversy. This study was undertaken to examine the prevalence of vascular disease in a prospective autopsy series of patients with clinically diagnosed dementia.

DESIGN

Structured review of clinical and neuropathological examinations. Clinical diagnoses were assigned in accordance with the recommendations of the NINCDS/ADRDA consensus panel. Neuropathological examinations were performed at an academic neuropathology service using published consensus criteria for the diagnosis of Alzheimer's disease and other forms of dementia.

SETTING

A subspecialty, outpatient dementia clinic in a university-affiliated suburban American hospital.

PARTICIPANTS

Eighty-seven unselected patients coming to autopsy who had undergone clinical dementia evaluation.

RESULTS

Dementia could not be attributed to the effects of cerebrovascular disease alone in any of the 87 patients coming to autopsy. Seventy-six (87%) of the patients were found to have Alzheimer's disease (AD), 44 had AD alone, and 32 had AD in combination with cerebrovascular disease (CVD). All of the patients with signs of CVD at autopsy were also found to have some concomitant neurodegenerative disease. The absence of patients in whom vascular dementia could be diagnosed at neuropathology was not the result of recruitment bias.

CONCLUSION

Clinicians should maintain a high index of suspicion of AD or other neurodegenerative process in older patients whose presenting complaint is dementia, even in the presence of well documented cerebrovascular disease.