Impact of changes in social anxiety on social functioning and quality of life in outpatients with schizophrenia: A naturalistic longitudinal study.

The prevalence of comorbid social anxiety disorder among patients with schizophrenia is currently attracting attention, and symptoms of social anxiety are reportedly associated with various clinical features. However, the contribution of social anxiety to social functioning and quality of life (QOL) over time remains obscure. The aim of this study was to examine the impact of changes in social anxiety symptoms on social functioning and QOL among outpatients with schizophrenia. Of the 207 outpatients who were eligible at baseline, 118 patients agreed with and completed a follow-up investigation at least 1 year (695.8 days on average) after the baseline study. Stepwise multiple regressions examining the change in social functioning using demographic data and changes in clinical variables as explanatory variables demonstrated that the changes in social anxiety and general psychopathology contributed to the change in the Social Functioning Scale, while the changes in clinical severity and negative symptoms contributed to the change in the Global Assessment of Functioning scale. Stepwise multiple regressions for the change in QOL demonstrated that the changes in social anxiety and depression contributed to the change in the World Health Organization QOL scale, Brief version, and the changes in social anxiety and positive symptoms contributed to the Subjective Well-being Under Neuroleptic Drug Treatment, Short Form. The results revealed that the changes in social anxiety symptoms were significantly associated with the change in functional outcome among patients with schizophrenia. Treatments targeting social anxiety seem to be key to achieving a full recovery in patients with schizophrenia.

Social anxiety and risk factors in patients with schizophrenia: Relationship with duration of untreated psychosis.

Social anxiety is commonly reported as a comorbid condition among people with schizophrenia. The aims of this study were to elucidate the associations between demographic/clinical features and social anxiety. A total of 207 outpatients with schizophrenia underwent assessments for social anxiety, psychiatric symptoms, social cognition, cognitive function, social functioning, and quality of life (QOL). To confirm the prediction model for social anxiety, we conducted multiple linear regressions using the Liebowitz Social Anxiety Scale (LSAS) score as an outcome variable and demographic/clinical variables as predictors. Of the 207 patients, 30 (14.5%) met the criteria for social anxiety disorder and 109 (52.7%) had a mean LSAS score higher than 30, suggesting that their social anxiety symptoms had reached a clinical level. Social anxiety was significantly correlated with psychiatric symptoms, social functioning, and QOL, whereas significant correlations with social cognition and cognitive function were not observed. A multiple regression analysis identified social functioning, gender, age of onset, and duration of untreated psychosis (DUP) as predictors that were most closely associated with the LSAS score. We confirmed that social anxiety symptoms were highly prevalent among outpatients with schizophrenia and were closely associated with social functioning and DUP, rather than social cognitive impairments.

Proteome analysis of soluble nuclear proteins reveals that HMGB1/2 suppress genotoxic stress in polyglutamine diseases.

Nuclear dysfunction is a key feature of the pathology of polyglutamine (polyQ) diseases. It has been suggested that mutant polyQ proteins impair functions of nuclear factors by interacting with them directly in the nucleus. However, a systematic analysis of quantitative changes in soluble nuclear proteins in neurons expressing mutant polyQ proteins has not been performed. Here, we perform a proteome analysis of soluble nuclear proteins prepared from neurons expressing huntingtin (Htt) or ataxin-1 (AT1) protein, and show that mutant AT1 and Htt similarly reduce the concentration of soluble high mobility group B1/2 (HMGB1/2) proteins. Immunoprecipitation and pulldown assays indicate that HMGBs interact with mutant AT1 and Htt. Immunohistochemistry showed that these proteins were reduced in the nuclear region outside of inclusion bodies in affected neurons. Compensatory expression of HMGBs ameliorated polyQ-induced pathology in primary neurons and in Drosophila polyQ models. Furthermore, HMGBs repressed genotoxic stress signals induced by mutant Htt or transcriptional repression. Thus, HMGBs may be critical regulators of polyQ disease pathology and could be targets for therapy development.

Transcriptional repression induces a slowly progressive atypical neuronal death associated with changes of YAP isoforms and p73.

Transcriptional disturbance is implicated in the pathology of polyglutamine diseases, including Huntington's disease (HD). However, it is unknown whether transcriptional repression leads to neuronal death or what forms that death might take. We found transcriptional repression-induced atypical death (TRIAD) of neurons to be distinct from apoptosis, necrosis, or autophagy. The progression of TRIAD was extremely slow in comparison with other types of cell death. Gene expression profiling revealed the reduction of full-length yes-associated protein (YAP), a p73 cofactor to promote apoptosis, as specific to TRIAD. Furthermore, novel neuron-specific YAP isoforms (YAPDeltaCs) were sustained during TRIAD to suppress neuronal death in a dominant-negative fashion. YAPDeltaCs and activated p73 were colocalized in the striatal neurons of HD patients and mutant huntingtin (htt) transgenic mice. YAPDeltaCs also markedly attenuated Htt-induced neuronal death in primary neuron and Drosophila melanogaster models. Collectively, transcriptional repression induces a novel prototype of neuronal death associated with the changes of YAP isoforms and p73, which might be relevant to the HD pathology.

PQBP-1 is expressed predominantly in the central nervous system during development.

Mutations of PQBP-1 (polyglutamine binding protein-1) have been shown recently to cause human mental retardation accompanied by microcephaly at a high frequency. As a first step towards understanding the molecular basis of this developmental anomaly, we analysed developmental expression of PQBP-1 by in situ hybridization, immunohistochemistry and Western blot analysis. Although it had been shown by Northern blot analysis that PQBP-1 mRNA is expressed in multiple organs in adult mice, our present results revealed that PQBP-1 mRNA and protein are dominantly expressed in the central nervous system (CNS) in embryos and in newborn mice. The mean expression level of PQBP-1 reaches a peak around birth and is down-regulated in adulthood. Furthermore, the expression pattern in the CNS changes remarkably following birth. PQBP-1 mRNA in the cerebral cortex is high in embryos but it rapidly decreases after birth. PQBP-1 mRNA increases in external and internal granular cell layers of the cerebellum from postnatal day 1 (P1) to P5. In addition, expression in the subventricular zone, where neurogenesis occurs, was high from P5 to adulthood. Collectively, these findings suggest that PQBP-1 might be involved in neuronal proliferation and/or maturation. These ideas may be relevant to the insufficient growth of brain structure reported in PQBP-1-linked human mental retardation.

Polyglutamine tract-binding protein-1 dysfunction induces cell death of neurons through mitochondrial stress.

Polyglutamine tract-binding protein-1 (PQBP-1) is a nuclear protein that interacts and colocalizes with mutant polyglutamine proteins. We previously reported that PQBP-1 transgenic mice show a late-onset motor neuron disease-like phenotype and cell death of motor neurons analogous to human neurodegeneration. To investigate the molecular mechanisms underlying the motor neuron death, we performed microarray analyses using the anterior horn tissues of the spinal cord and compared gene expression profiles between pre-symptomatic transgenic and age-matched control mice. Surprisingly, half of the spots changed more than 1.5-fold turned out to be genes transcribed from the mitochondrial genome. Northern and western analyses confirmed up-regulation of representative mitochondrial genes, cytochrome c oxidase (COX) subunit 1 and 2. Immunohistochemistry revealed that COX1 and COX2 proteins are increased in spinal motor neurons. Electron microscopic analyses revealed morphological abnormalities of mitochondria in the motor neurons. PQBP-1 overexpression in primary neurons by adenovirus vector induced abnormalities of mitochondrial membrane potential from day 5, while cytochrome c release and caspase 3 activation were observed on day 9. An increase of cell death by PQBP-1 was also confirmed on day 9. Collectively, these results indicate that dysfunction of PQBP-1 induces mitochondrial stress, a key molecular pathomechanism that is shared among human neurodegenerative disorders.