[Usefulness of an anti-mouse cerebellar tissue-derived antigen antibody test in predicting immunotherapy efficacy in patients with idiopathic cerebellar ataxia].

BACKGROUND: Autoimmune cerebellar ataxia (AICA) is a general term for diseases in which the cerebellum is damaged by an autoimmune mechanism. For the diagnosis of the AICA, anti-thyroid antibodies (anti-thyroid peroxidase antibody and anti-thyroglobulin antibody), anti-glutamic acid decarboxylase (GAD) antibodies, and anti-gliadin antibodies are measured. Immunotherapy is known to be effective for AICA, but some patients with effective immunotherapy lack autoantibodies associated with cerebellar ataxia. The purpose of this study was to clarify whether the effectiveness of immunotherapy in patients with suspected AICA could be predicted by anti-mouse cerebellar tissue-derived antigen antibody tests. METHODS: This study was conducted on 25 patients with idiopathic cerebellar ataxia (excluding multiple system atrophy, hereditary spinocerebellar degeneration, cancer-bearing patients, and patients taking phenytoin) who received immunotherapy from 2005 to 2016 at Tokyo Medical University Hachioji Medical Center. The patients were suspected of having AICA because they were positive for cerebellar ataxia-related autoantibodies (anti-thyroid antibody, anti-GAD antibody, anti-gliadin antibody, or anti-transglutaminase 6 antibody) or other autoantibodies. Antibodies that bind to mouse cerebellar tissue-derived antigens were defined as "anti-mouse cerebellar tissue-derived antigen antibodies" in this study, and their IgG-class antibodies were comprehensively measured using a slot blot. RESULTS: Anti-mouse cerebellar tissue-derived antigen antibody test results were correlated with immunotherapy efficacy. Furthermore, the combination of anti-mouse cerebellar tissue-derived antigen and anti-GAD antibody tests could predict the effectiveness of immunotherapy with 83% sensitivity and 100% specificity, while the combination of the anti-mouse cerebellar tissue-derived antigen, anti-GAD, and anti-gliadin (IgA class) antibody tests could predict the effectiveness of immunotherapy with 94% sensitivity and 86% specificity. CONCLUSION: Anti-mouse cerebellar tissue-derived antigen antibody tests could help to provide useful information for immunotherapy administration to patients with idiopathic cerebellar ataxia suspected to be AICA.

Primary intrahepatic squamous cell carcinoma in a sika deer.

A white nodule was detected in the liver of a wild female sika deer. The nodule was histologically diagnosed as squamous cell carcinoma (SCC), and it transitioned into a hyperplastic and chronically inflamed intrahepatic bile duct showing Fasciola infection. Therefore, the tumor was demonstrated to have originated from the biliary epithelium of the intrahepatic bile duct. Hyperplastic and chronic inflammatory changes of the biliary epithelium might have contributed the carcinogenesis of the present case, as proposed in human primary intrahepatic SCC cases. To the best of our knowledge, this is the first reported case of primary intrahepatic SCC in an animal.

[Cerebellar Ataxia and Autoantibodies].

The cerebellum is one of the main targets in the central nervous system for autoimmunity. Immune-mediated cerebellar ataxias include gluten ataxia, GAD antibody-associated cerebellar ataxia, Hashimoto's encephalopathy, and paraneoplastic cerebellar degeneration. Autoimmune cerebellar ataxia may be of either insidious or subacute onset, and vertigo or transient neurological symptoms occur in some patients before the onset of the disease, in contrast to spinocerebellar degeneration. If autoimmune cerebellar ataxia is suspected, early diagnosis and introduction of treatment are very important. For diagnosis, testing for gliadin antibody, TG6 antibody, GAD antibody, thyroid antibody, and anti-neuronal antibodies, including mGluR1, is useful. Magnetic resonance imaging voxel-based morphometry is also useful because it can detect cortical cerebellar atrophy of autoimmune cerebellar ataxia, different from spinocerebellar ataxia. As for treatment, it is important to remove autoimmune triggering factors (e.g.,dietary gluten or neoplasm). When the ataxia symptoms are causing hindrances in the daily life, it is worth considering immunotherapy including IVIg, steroid therapy and so on.

Syntaxin 17 promotes lipid droplet formation by regulating the distribution of acyl-CoA synthetase 3.

Lipid droplets (LDs) are ubiquitous organelles that contain neutral lipids and are surrounded by a phospholipid monolayer. How proteins specifically localize to the phospholipid monolayer of the LD surface has been a matter of extensive investigations. In the present study, we show that syntaxin 17 (Stx17), a soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) protein whose expression in the liver is regulated by diet, participates in LD biogenesis by regulating the distribution of acyl-CoA synthetase (ACSL)3, a key enzyme for LD biogenesis that redistributes from the endoplasmic reticulum (ER) to LDs during LD formation. Stx17 interacts with ACSL3, but not with LD formation-unrelated ACSL1 or ACSL4, through its SNARE domain. The interaction occurs at the ER-mitochondria interface and depends on the active site occupancy of ACSL3. Depletion of Stx17 impairs ACSL3 redistribution to nascent LDs. The defect in LD maturation due to Stx17 knockdown can be compensated for by ACSL3 overexpression, suggesting that Stx17 increases the efficiency of ACSL3 redistribution to LDs. Moreover, we show that the interaction between Stx17 and ACSL3 during LD maturation may be regulated by synaptosomal-associated protein of 23 kDa.

Prevalence of Autoantibodies and the Efficacy of Immunotherapy for Autoimmune Cerebellar Ataxia.

OBJECTIVE: Autoimmune cerebellar ataxias were recently reported to be treatable. However, the proportion of patients with cortical cerebellar atrophy of unknown etiology with autoimmune-associated cerebellar ataxia and the actual effectiveness of immunotherapy in these diseases remain unknown. METHODS: We measured the level of autoantibodies (including anti-gliadin antibody, anti-glutamic acid decarboxylase (GAD) antibody, and anti-thyroid antibody) in 58 Japanese patients with cerebellar ataxia, excluding those with multiple system atrophy, hereditary spinocerebellar ataxia, cancer, or those who were receiving phenytoin, and the efficacy of immunotherapy was assessed. RESULTS: Thirty-one of 58 (53%) patients were positive for anti-GAD antibody, anti-gliadin antibody, or anti-thyroid antibody. Seven of the 12 anti-gliadin antibody-positive patients, three of the four anti-GAD antibody-positive patients, and three of the six anti-thyroid antibody-positive patients responded well to immunotherapy, indicating that 59% of patients with ataxia-associated antibody-positive cerebellar ataxia undergoing immunotherapy responded well. CONCLUSION: Some patients with cerebellar ataxia have autoimmune conditions and diagnosing autoimmune cerebellar ataxia is therefore an important component in the care of patients with this disease entity.

Identification of acyl-CoA thioesterase in mouse mesenteric lymph nodes.

Acyl-CoA thioesterases (ACOTs) are a group of enzymes that catalyze the hydrolysis of fatty acyl-CoAs to free fatty acids and CoA, with the potential to regulate the intracellular levels of these molecules. In this study, we show that a cytosolic isoform, ACOT7, is expressed at a significant level in the mesenteric lymph nodes (MLNs) of mice. While crude preparations of the mesenteric visceral fat contained significant levels of palmitoyl-CoA thioesterase activity, enzyme activity was concentrated 6.9-fold in MLNs compared with the residual adipose portion after excision of MLNs. When MLN homogenates were centrifuged, 82% of the enzyme activity was recovered in the cytosolic fraction, concomitant with almost exclusive recovery of ACOT7. Immunoprecipitation using anti-ACOT7 antibody estimated that 87% of enzyme activity in the homogenates was accounted for by ACOT7. On MLN sections, the germinal centers of secondary lymphoid follicles were immunostained with the antibody. In MLNs of mice fasted for 16 h, ACOT7 levels were induced 1.8-fold, which reflected a 1.5-fold increase in enzyme activity. These findings suggest that ACOT7 may be involved in dietary intake-associated responses in fatty acid metabolism in MLNs.

Quantitative evaluation of the role of cysteine and methionine residues in the antioxidant activity of human serum albumin using recombinant mutants.

The importance of cysteine (Cys) and methionine (Met) residues for the antioxidant activity of human serum albumin (HSA) was investigated using recombinant HSA mutants, in which Cys34 and/or the six Met residues had been mutated to Ala. The scavenging activities of the mutants against five reactive oxygen and nitrogen species were evaluated by a chemiluminescence assay, electron paramagnetic resonance spectroscopy, or a HPLC-flow reactor assay. Our results showed that the contributions of Cys34 and the Met residues to the antioxidant activity of HSA were 61% and 29% against O(2)(•-), 68% and 61% against H(2)O(2), 38% and 6% against HO(•), 36% and 13% against HOCl, and 51% and 1% against (•)NO, respectively. Thus, the findings propose in a direct way that Cys34 plays a more important role than the Met residues in the antioxidant activity of HSA.

Eosinophils are required for the induction of bronchial hyperresponsiveness in a Th transfer model of BALB/c background.

BACKGROUND: Helper T (Th) cells are deeply involved in the pathophysiology of bronchial asthma, such as eosinophilic inflammation, bronchial hyperresponsiveness (BHR), airflow limitation and remodeling. It is still unclear whether Th cells contribute to BHR independently of eosinophilic inflammation. The double GATA (dblGATA) site is a high-affinity GATA-binding site in the GATA-1 promoter. dblGATA site-deficient (Delta dblGATA) mice lack eosinophils. METHOD: Ovalbumin (OVA)-reactive Th clones were transferred into Delta dblGATA and wild-type (WT) mice of BALB/c background. The number of eosinophils in the bronchoalveolar lavage fluid (BALF) and bronchial responsiveness to methacholine were examined after OVA challenge. RESULTS: The number of BALF eosinophils was significantly increased in WT mice, but not detectable in Delta dblGATA mice. BHR was also induced in WT mice, but significantly attenuated in Delta dblGATA mice. CONCLUSION: Eosinophils are involved in T-cell-mediated BHR.

Sterol Regulatory Element-Binding Protein-2 modulates human brain acyl-CoA hydrolase gene transcription.

The brain shows high catalyzing activity during hydrolysis of long-chain acyl-CoAs into fatty acids and CoA-SH. Brain acyl-CoA hydrolase (BACH) is responsible for most of the long-chain acyl-CoA hydrolyzing activity in the brain and is localized exclusively in neurons. We analyzed the human BACH gene promoter, focusing on transcriptional regulation by Sterol Regulatory Element-Binding Protein-2 (SREBP-2), which is a transcription factor that activates genes involved in cholesterol biosynthesis and uptake. When the nuclear form of SREBP-2 gene was transfected into human neuroblastoma cells, transcription of a BACH gene promoter-luciferase reporter gene was activated through a sterol regulatory element (SRE) motif. Moreover, a gel shift assay demonstrated that SREBP-2 specifically bound to the SRE motif. These results suggest that transcription of the BACH gene is activated by SREBP-2. This study also provides insights into BACH function in the interaction between the metabolism of acyl-CoAs and cholesterol in neurons.

A 50-kDa isoform of mouse brain acyl-CoA hydrolase: expression and molecular properties.

Brain acyl-CoA hydrolase (BACH) is responsible for most of the long-chain acyl-CoA hydrolyzing activity in the brain and is localized exclusively in neurons. There are two BACH isoforms: the major isoform, a 43-kDa BACH, and a lesser isoform, a 50-kDa BACH. In our previous work [Brain Res. Mol. Brain Res. 98 (2002) 81], a possibility was raised that these BACH isoforms might be generated from a single mRNA species via a mechanism of alternative use of translation start sites. However, the results obtained in the current study indicated that the 43-kDa BACH and 50-kDa BACH are not generated from a single mRNA species, but from distinct mRNA species transcribed by alternative use of transcription start sites. The molecular properties of the 50-kDa BACH were compared to those of the 43-kDa BACH. Palmitoyl-CoA hydrolase activity and protein stability were almost the same between both BACH isoforms. In addition, both 43-kDa BACH and 50-kDa BACH that were fused to green fluorescent protein showed cytosolic distribution. These results suggest that the 50-kDa BACH plays a similar role as the 43-kDa BACH. Therefore, since the 43-kDa BACH is expressed at higher levels than 50-kDa BACH, the 43-kDa BACH should largely contribute to understanding the physiological functions of the BACH gene in neurons.

Characterization of mouse homolog of brain acyl-CoA hydrolase: molecular cloning and neuronal localization.

Acyl-CoA hydrolase could provide a mechanism via its potency to modulate cellular concentrations of acyl-CoAs for the regulation of various cellular events including fatty acid metabolism and gene expression. However, only limited evidence of this is available. To better understand the physiological role of this enzyme, we characterized a mouse brain acyl-CoA hydrolase, mBACH. The cloned cDNA for mBACH encoded a 338-amino-acid polypeptide with >95% identity to the human and rat homologs, indicating that the BACH gene is highly conserved among species. This was supported by the similarity in genomic organization of the BACH gene between humans and mice. Bacterially expressed mBACH was highly active against long-chain acyl-CoAs with a relatively broad specificity for chain length. While palmitoyl-CoA hydrolase activity was widely distributed in mouse tissues, it was marked in the brain, consistent with mBACH being almost exclusively distributed in this tissue, where >80% of the enzyme activity was explained by mBACH present in the cytosol. Immunohistochemistry demonstrated a neuronal localization of mBACH in both the central and peripheral nervous systems. In neurons, mBACH was distributed throughout the cell body and neurites. Although four isoforms except mBACH itself, that may be generated by the alternative use of exons of a single mBACH gene, were cloned, their mRNA levels in the brain were estimated to be negligible. However, a 50-kDa polypeptide besides the major one of 43-kDa seemed to be translated from the mBACH mRNA with differential in-frame ATG triplets used as the initiation codon. These findings will contribute to the functional analysis of the BACH gene using mice including genetic studies.