Formation of intracellular aggregates is the hallmark of polyglutamine (polyQ) diseases. We analyzed the components of purified nuclear polyQ aggregates by mass spectrometry. As a result, we found that the RNA-binding protein translocated in liposarcoma (TLS) was one of the major components of nuclear polyQ aggregate-interacting proteins in a Huntington disease cell model and was also associated with neuronal intranuclear inclusions of R6/2 mice. In vitro study revealed that TLS could directly bind to truncated N-terminal huntingtin (tNhtt) aggregates but could not bind to monomer GST-tNhtt with 18, 42, or 62Q, indicating that the tNhtt protein acquired the ability to sequester TLS after forming aggregates. Thioflavin T assay and electron microscopic study further supported the idea that TLS bound to tNhtt-42Q aggregates at the early stage of tNhtt-42Q amyloid formation. Immunohistochemistry showed that TLS was associated with neuronal intranuclear inclusions of Huntington disease human brain. Because TLS has a variety of functional roles, the sequestration of TLS to polyQ aggregates may play a role in diverse pathological changes in the brains of patients with polyQ diseases. Huntington disease (HD)2 is a hereditary neurodegenerative disease caused by an expansion of the CAG repeat located in exon 1 of the HD gene (1). Expansion of the polyglutamine (polyQ) stretch in huntingtin (htt), the HD gene product, leads to the formation of intracellular aggregates (2, 3). Previous studies have demonstrated that nuclear accumulation of insoluble polyQ aggregates or formation of neuronal intranuclear inclusions is closely correlated with disease progression (4 -6), and disruption of nuclear physiological processes may account for many of the disease phenotypes in the mouse models generated by expressing mutant N-terminal fragments of htt (7).There are many aggregate-interacting proteins (AIPs), some of which, including the heat shock protein (Hsp) 40, 70, and 90 families, are thought to suppress aggregate formation and cellular toxicity induced by expanded polyQ proteins (8, 9). In addition, functionally important proteins, including transcription factors (10 -12) and members of the ubiquitin-proteosome pathway (13,14), are sequestered in the polyQ aggregates, which could cause their loss of function and result in cellular dysfunction. These studies suggest that the components of AIPs reflect either the cellular defense against polyQ aggregates or the cellular machinery affected by polyQ aggregates. Therefore, identification of AIPs should help elucidate the process of aggregate formation, the cellular response to aggregates, and the mechanisms of cellular dysfunction caused by the polyQ aggregates, but the AIPs are still not fully uncovered.We have previously established a method to identify the components of nuclear polyQ AIPs from Neuro2a cells stably transfected with tNhtt-150Q-EGFP-NLS (HD150Q-NLS cells), which express a cDNA encoding htt exon 1 containing 150 CAG repeats and fused with enhanced green fluorescent pr...

The role of aryl hydrocarbon receptor (AhR) on the antiandrogenic effects of polycyclic aromatic hydrocarbons (PAHs) was studied in LNCaP cells. The PAHs used in this study were chrysene (Chr), benzo[ k]fluoranthene (BkF), benzo[ a]pyrene (BaP), anthracene (Ant) and pyrene (Pyr). Chr, BkF and BaP acted as AhR agonists in LNCaP cells, while Ant and Pyr did not. The antiandrogenic effects of the PAHs were evaluated on the basis of regulation of prostate-specific antigen (PSA) mRNA and protein levels by 5alpha-dihydrotestosterone (DHT). Chr, BkF and BaP exhibited an antiandrogenic effect, but Ant and Pyr did not. alpha-Naphthoflavone (alpha-NF), an AhR antagonist, reversed the antiandrogen action of Chr, BkF and BaP, suggesting a requirement for activated AhR. The antiandrogenic PAHs did not significantly decrease androgen receptor (AR) levels or cellular DHT concentrations. Gel mobility shift assays revealed that Chr, BkF and BaP inhibited the binding of AR in nuclear extracts to oligonucleotide probes containing the AR-responsive element (ARE), whereas Ant and Pyr had no effect. The antiandrogenic PAHs elevated mRNA levels of c-fos and c-jun. Since activator protein-1 (AP-1), a heterodimer of c-jun and c-fos proteins, is known to inhibit binding of AR to ARE by protein-protein interaction with AR, the findings in the present study suggest a possible involvement of AP-1 in the antiandrogenic effects of PAHs acting as AhR agonists. These results suggest that AhR can stimulate AP-1 expression resulting in inhibition of the binding of AR to ARE in the transcription regulatory region of target genes such as PSA.

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We collected diesel exhaust particles (DEPs) emitted from three diesel-engine vehicles--a car, a bus, and a truck--in daily use, and prepared DEP extracts (DEPEs), designated as EC, EB, or ET, respectively. The androgenic and antiandrogenic effects of the DEPE samples were examined by a luciferase reporter assay in human prostate carcinoma PC3/AR cells transiently transfected with a prostate specific antigen gene promoter-driven luciferase expression vector pGLPSA5.8. PC3/AR is a subline of human prostate carcinoma PC3 transformed to stably express wild-type human androgen receptor (AR). While DEPE samples did not exhibit any androgenic effect, they exerted antiandrogenic effect, inhibiting dihydrotestosterone (10 pM) -induced luciferase activity by 24 to 52% at an extract concentration of 10 microg/ml. The antiandrogenic effect was greater in the following order: ET > EB > EC. Co-treatment of PC3/AR cells with SKF-525A, a nonselective inhibitor of cytochrome P450 (CYP) enzymes, enhanced the antiandrogenic effect, indicating that the antiandrogenic effect is caused by intact species of DEPE constituents. The antiandrogenic effect of DEPE samples was reversed by alpha-naphthoflavone, an aryl hydrocarbon receptor (AhR) antagonist. The antiandrogenic activity of a DEPE sample correlated with its AhR agonist activity assayed in PC3/AR cells transiently transfected with CYP1A1 gene promoter-driven luciferase expression vector pLUC1A1. Equimolar mixtures of ten polycyclic aromatic hydrocarbons (PAHs) having four or more rings, structures found in the DEPEs, showed significant antiandrogenic effects and AhR agonist activity at concentrations equivalent to those found in DEPE samples. Further, DEPE samples elicited only antiandrogenic effects in recombinant yeast cells, which express beta-galactosidase in response to androgen. A competitive AR binding assay showed that AR-binding constituents exist in DEPE samples, indicating that greater part of AR-binding constituents in DEPEs are AR antagonists. All these findings show that DEPE samples exhibit significant antiandrogenic effect in cell-based transcription assay and that this effect is due in part to the constituents with AhR agonist activity including PAHs and to the constituents with AR antagonist activity.

Cyclodextrin-modified micellar electrokinetic chromatography was applied to the enantioseparation of vinclozolin, which has been used as a fungicide and has an anti-androgenic activity, using gamma-cyclodextrin together with sodium dodecyl sulfate. Factors affecting the chiral resolution and migration time of vinclozolin were studied. The optimum running conditions were found to be 20 mM phosphate-5 mM borate buffer (pH 8.5) containing 50 mM gamma-cyclodextrin and 100 mM sodium dodecyl sulfate with an effective voltage of 20 kV at 20 degrees C using direct detection at 203 nm. Under these conditions, the resolution (Rs) of racemic vinclozolin was approximately 2.1. The sample was concentrated by solid-phase extraction and was fractionated by HPLC. The peak area ratio of (+)- and (-)-vinclozolins in wine was found to be 2:3, namely, not racemic, suggesting that degradation rates were different between (+)- and (-)-vinclozolins. The anti-androgenic activities of (+)- and (-)-vinclozolins on dihydrotestosterone-induced transcription were also investigated. The anti-androgenic activity of (+)-vinclozolin tended to be stronger than that of (-)-vinclozolin, suggesting the possibility that vinclozolin can act as an enantioselective anti-androgen.