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DJ-1, a protein that promotes the action of multiple anti-apoptotic/pro-survival pathways, is expressed prominently in human reactive astrocytes and in many human cancers. Glioblastomas (GBMs) are the most common adult primary brain tumor, and most show either abnormalities in p53 or epidermal growth factor receptor (EGFR) amplification, but not both. In this retrospective study of 40 surgically resected GBMs, we compared the immunohistochemical intensity of DJ-1 expression (based on blinded scoring by independent examiners) to these and other molecular factors associated with GBM oncogenesis. We report here that: (i) most of the GBMs that we studied expressed DJ-1 protein at significant levels, and typically in a cytoplasmic, non-nuclear fashion; (ii) DJ-1 staining intensity varied directly with strong nuclear p53 expression (assessed by immunostaining); and (iii) DJ-1 staining intensity varied inversely with EGFR amplification (assessed by fluorescent in situ hybridization). Since the anti-apoptotic/pro-survival actions of DJ-1 have been clearly linked in in vitro systems to p53 and receptor tyrosine kinase (i.e. EGFR) pathways that are hypothesized to be critical to GBM genesis, these observations indicate that DJ-1 expression may play a role in the biology of some types of GBMs. Therefore, given the new associations presented here between DJ-1, p53 and EGFR amplification in GBMs, future investigations of these tumors should include an analysis of DJ-1 to determine whether its expression pattern is important for tumor progression, prognosis and responsiveness to therapy. [ABSTRACT FROM AUTHOR]

DJ-1 is a protein with anti-oxidative stress and anti-apoptotic properties that is abundantly expressed in reactive CNS astrocytes in chronic neurodegenerative disorders such as Parkinson's disease (PD), Alzheimer's disease (AD), and Pick's disease. Genetic mutations which eliminate DJ-1 expression in humans are sufficient to produce an early-onset form of familial PD, PARK7, suggesting that DJ-1 is a critical component of the neuroprotective arsenal of the brain. Previous studies in parkinsonism/dementia brain tissues have revealed that reactive astrocytes within and surrounding incidentally identified infarcts were often robustly immunoreactive for DJ-1, especially if the infarcts showed histological features consistent with older age. Given this, we sought to evaluate astrocytic DJ-1 expression in human stroke more extensively, and with a particular emphasis on determining whether immunohistochemical DJ-1 expression in astrocytes correlates with histological infarct age. The studies presented here show that DJ-1 is abundantly expressed in reactive infarct region astrocytes in both gray and white matter, that subacute and chronic infarct region astrocytes are much more robustly DJ-1+ than are acute infarct and non-infarct region astrocytes, and that DJ-1 staining intensity in astrocytes generally correlates with that of the reactive astrocyte marker GFAP. Confocal imaging of DJ-1 and GFAP dual-labelled human brain sections were used to confirm the localization to and expression of DJ-1 in astrocytes. Neuronal DJ-1 staining was minimal under all infarct and non-infarct conditions. Our data support the conclusion that the major cellular DJ-1 response to stroke in the human brain is astrocytic, and that there is a temporal correlation between DJ-1 expression in these cells and advanced infarct age. [ABSTRACT FROM AUTHOR]

Abstract: Mutations that eliminate DJ-1 expression cause a familial form of Parkinson''s disease (PD). In sporadic PD, and many other neurodegenerative diseases, reactive astrocytes over-express DJ-1 whereas neurons maintain its expression at non-disease levels. Since DJ-1 has neuroprotective properties, and since astrocytes are known to support and protect neurons, DJ-1 over-expression in reactive astrocytes may reflect an attempt by these cells to protect themselves and surrounding neurons against disease progression. We used neuron–astrocyte contact and non-contact co-cultures to show that DJ-1 knock-down in astrocytes impaired their neuroprotective capacity, relative to wild-type astrocytes, against the neurotoxin rotenone. Conversely, DJ-1 over-expression in astrocytes augmented their neuroprotective capacity. Experiments using astrocyte conditioned media on neuron-only cultures suggested that astrocyte-released, soluble factors were involved in the DJ-1-dependent, astrocyte-mediated neuroprotective mechanism. Our findings support the developing view that astrocytic dysfunction, in addition to neuronal dysfunction, may contribute to the progression of a variety of neurodegenerative disorders. [Copyright &y& Elsevier]

Abstract: Loss-of-function mutations in the human PARK7 gene, encoding DJ-1, are a rare cause of autosomal recessive Parkinson''s disease (ARPD). To facilitate generation of a novel vertebrate model, in which to examine the biochemical functions of DJ-1 in vivo, we cloned and characterized the zebrafish orthologue of DJ-1 (zDJ-1). The 0.95 kb zDJ-1 mRNA is expressed in adult zebrafish brain, muscle and gut, and in the embryo from 24 h post-fertilization. The zDJ-1 transcript encodes a 19.8 kDa, 189 amino acid protein, which is 83% identical to human DJ-1. Residues thought to be functionally important sites of post-translational modification in human DJ-1, and critical positions affected by pathogenic missense mutations in ARPD patients, are conserved in zDJ-1. The 14 kb zDJ-1 gene contains six exons and is located on zebrafish chromosome 8; the structure of the gene is highly homologous to human DJ-1, except that there are no alternatively spliced non-coding 5′ exons. The single zDJ-1 first exon shows 5′ end heterogeneity, reflecting multiple transcription start sites. In the adult zebrafish brain, zDJ-1 immunoreactivity was prominent in the cytoplasm of most neurons, and in the neuropil, but was less evident within white matter tracts, consistent with neuronal somatic and dendritic localization. Dopaminergic neurons in each of the major forebrain and diencephalic TH-positive cell groups expressed zDJ-1. These studies show that zDJ-1 is very similar to human DJ-1 and delineate essential resources, allowing further examination of the function and regulation of DJ-1, using the zebrafish as a model. [Copyright &y& Elsevier]