Multi-modal brain magnetic resonance imaging database covering marmosets with a wide age range.

Magnetic resonance imaging (MRI) is a non-invasive neuroimaging technique that is useful for identifying normal developmental and aging processes and for data sharing. Marmosets have a relatively shorter life expectancy than other primates, including humans, because they grow and age faster. Therefore, the common marmoset model is effective in aging research. The current study investigated the aging process of the marmoset brain and provided an open MRI database of marmosets across a wide age range. The Brain/MINDS Marmoset Brain MRI Dataset contains brain MRI information from 216 marmosets ranging in age from 1 and 10 years. At the time of its release, it is the largest public dataset in the world. It also includes multi-contrast MRI images. In addition, 91 of 216 animals have corresponding high-resolution ex vivo MRI datasets. Our MRI database, available at the Brain/MINDS Data Portal, might help to understand the effects of various factors, such as age, sex, body size, and fixation, on the brain. It can also contribute to and accelerate brain science studies worldwide.

The Brain/MINDS 3D digital marmoset brain atlas.

We present a new 3D digital brain atlas of the non-human primate, common marmoset monkey (Callithrix jacchus), with MRI and coregistered Nissl histology data. To the best of our knowledge this is the first comprehensive digital 3D brain atlas of the common marmoset having normalized multi-modal data, cortical and sub-cortical segmentation, and in a common file format (NIfTI). The atlas can be registered to new data, is useful for connectomics, functional studies, simulation and as a reference. The atlas was based on previously published work but we provide several critical improvements to make this release valuable for researchers. Nissl histology images were processed to remove illumination and shape artifacts and then normalized to the MRI data. Brain region segmentation is provided for both hemispheres. The data is in the NIfTI format making it easy to integrate into neuroscience pipelines, whereas the previous atlas was in an inaccessible file format. We also provide cortical, mid-cortical and white matter boundary segmentations useful for visualization and analysis.

Synthesis of 3-Arylmethyl-2-oxindole Derivatives and Their Effects on Neuronal Cell Death.

Various 3-arylmethyl-2-oxindole derivatives were synthesized by the Knoevenagel condensation of oxindole and aromatic aldehydes followed by palladium-mediated hydrogenation or hydride-reduction. Further substituted derivatives at C-3 and/or N-1 of the oxindole skeleton were prepared from the condensation products. Their protective effect against neuronal cell death induced by oxidative stress was evaluated by lactate dehydrogenase assay. A structure-activity relationship study revealed that compounds with any of the dialkylamino, nitro or hydroxy groups on the 3-arylmethyl moieties elicit a superior potency to suppress cell death, while others are ineffective. Substitutions with less polar functional groups on the benzene or lactam ring of the oxindole skeleton positively, but not remarkably, affect the potency. In addition, the stereochemistry at C-3 of the oxindole core was not a crucial factor for the neuroprotective activity of the compounds.

MPIase is a glycolipozyme essential for membrane protein integration.

Protein integration into biological membranes is a vital cellular event for all organisms. We previously reported an integration factor in the inner membrane of Escherichia coli, named MPIase (membrane protein integrase). Here we show that in contrast to previously identified integration factors that are proteins, MPIase is a glycolipid composed of diacylglycerol and a glycan chain of three acetylated aminosugars linked through pyrophosphate. Hydrolytic removal of the lipid moiety gives a soluble product with higher integration activity than that of the original MPIase. This soluble form of MPIase directly interacts with a newborn membrane protein, maintaining its integration-competent structure and allowing its post-translational integration. MPIase actively drives protein integration following chaperoning membrane proteins. We further demonstrate with anti-MPIase antibodies that MPIase is likely involved in integration in vivo. Collectively, our results suggest that MPIase, essential for membrane protein integration, is to our knowledge the first glycolipid with an enzyme-like activity.

Lipopolysaccharide induces raft domain expansion in membrane composed of a phospholipid-cholesterol-sphingomyelin ternary system.

The molecular behavior and interaction of Re-type lipopolysaccharide (ReLPS) and phospholipids were investigated in two different types of model membrane systems, a pure phospholipid membrane consisting of 1,2-dielaidoyl-snglycero-3-phosphoethanolamine (DEPE) and a raft-forming membrane composed of equimolar DEPE, sphingomyelin (SM), and cholesterol (Chol) by solid-state NMR spectroscopy. A remarkable influence of ReLPS on the property of lipid bilayer was found by analyzing the (13)C-NMR spectra. Namely, while both liquid-ordered (L(o)) and liquid-disordered (L(d)) phases co-exist in DEPE/SM/Chol, only the L(o) phase is present in DEPE/SM/Chol/ReLPS. This clearly indicates that ReLPS induces expansion of the raft area in the raft-forming membrane. The (1)H spin-lattice relaxation times in the rotating frame T( 1ρ) (H) in the two different membranes, DEPE/ReLPS and DEPE/SM/Chol/ReLPS, indicate that the motion of DEPE is affected by the presence of ReLPS, Chol, and SM, and much faster than that of ReLPS in both membranes. The ReLPS in the raft-forming membrane, in particular, accelerated the movement of DEPE. Thus, this study shows the possibility that LPS induces the expansion of raft region and the rapid motion of the raft-forming membranes to favor molecular interactions in the animal cell membrane during innate immune recognition.

Induction of arginase II mRNA by nitric oxide using an in vitro model of gyrate atrophy of choroid and retina.

PURPOSE: The authors previously reported ornithine cytotoxicity in ornithine-δ-aminotransferase (OAT)-deficient human retinal pigment epithelial (RPE) cells as an in vitro model of gyrate atrophy of the choroid and retina (GA). Given that RPE cells are severely damaged by arginine combined with ornithine, they investigated the role of arginine metabolism using that in vitro model. METHODS: Human telomerase reverse transcriptase (hTERT)-RPE cells were incubated with ornithine or other agents in the presence of 5-fluoromethylornithine (5-FMO), an OAT-specific inhibitor. mRNA expression was determined by quantitative real-time polymerase chain reaction, and the concentration of nitric oxide (NO) was quantified using a Griess assay. Furthermore, cytotoxicity was examined by morphologic observations and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) colorimetric assays, with the effect of arginase II examined using short interfering (si) RNA for arginase II and S-(2-boronoethyl)-L-cysteine (BEC), an arginase inhibitor. RESULTS: NO production in 5-FMO-treated hTERT-RPE cells was increased by ornithine, and the NO donors S-nitroso-N-acetyl-DL-penicillamine (SNAP) and S-nitrosoglutathione induced cytotoxicity. Ornithine increased the expression of arginase II mRNA in 5-FMO-treated cells. Arginase II upregulation was partially inhibited by an NO synthase inhibitor, N(G)-nitro-L-arginine methyl ester, which was mimicked by SNAP. Arginase II siRNA and BEC enhanced ornithine cytotoxicity, and arginase II silencing resulted in a further increase in NO production. CONCLUSIONS: These results demonstrate that NO is produced in our in vitro GA model, which induced cytotoxicity of RPE cells and upregulation of arginase II. NO may be involved in RPE degeneration in GA through the regulation of arginase II mRNA expression.

A novel complete reconstitution system for membrane integration of the simplest membrane protein.

A complete reconstitution system for membrane integration of the simplest protein was developed by means of defined factors. A mutant version of Pf3 coat protein, 3L-Pf3 coat, requires neither signal recognition particle/Sec factors nor a membrane potential for its integration into the cytoplasmic membrane of Escherichia coli. Although 3L-Pf3 coat is spontaneously integrated into liposomes composed of phospholipids, diacylglycerol completely blocks such spontaneous integrations at a physiological level. Under the conditions where spontaneous integration does not occur, 3L-Pf3 coat integration was absolutely dependent on a novel integration-stimulating factor. Combination of the PURE system, an in vitro translation system composed of the purified factors involved in translation in E. coli, with liposomes containing the highly purified integration-stimulating factor revealed multiple cycles of 3L-Pf3 coat integration, achieving the complete reconstitution of membrane integration. Based on the function of the factor, we propose that the factor is named MPIase (Membrane Protein Integrase).

Neuroprotective effects of (arylthio)cyclopentenone derivatives on manganese-induced apoptosis in PC12 cells.

Parkinson's disease is characterized by degeneration of dopaminergic neurones in the substantia nigra. Chronic manganese poisoning shares many features of Parkinson's disease, and also induces extrapyramidal syndromes that resemble those of Parkinson's disease due to dopamine depletion in the central nervous system. This study was undertaken to develop novel neuroprotective drugs via the identification of compounds that inhibit manganese-induced apoptosis. Here, we report that (arylthio)cyclopentenone derivatives, which are synthetic analogs of cyclopentenone prostaglandins, prevent manganese-induced apoptosis in PC12 cells. A highly sensitive assay of caspase-3/7 activity was used for screening newly synthesized prostaglandin analogs. The results showed that some cyclopentenone derivatives (GIF-0642, GIF-0643, GIF-0644, GIF-0745, and GIF-0747) inhibit manganese-induced caspase-3/7 activation in a concentration-dependent manner. Effective compounds all have an arylthio group, indicating that this structure plays an important role in the anti-apoptotic effects of (arylthio)cyclopentenone derivatives. The anti-apoptotic effects of these compounds were confirmed by verifying their ability to inhibit the DNA fragmentation and caspase-9 activation induced by manganese. Furthermore, GIF-0747 prevented manganese-induced cytochrome c release from mitochondria. These results suggest that (arylthio)cyclopentenone derivatives may be good candidates for treating neurodegenerative diseases.

(Arylthio)cyclopentenones derivatives prevent glutamate-induced HT22 cell death through a PPAR gamma-dependent pathway.

We show that cyclopentenone derivatives, which are synthetic analogs of cyclopentenone prostaglandins, are neuroprotective against glutamate-induced oxidative stress in HT22 cells. This effect was antagonized by a peroxisome proliferator-activated receptor-gamma (PPAR gamma) antagonist, T0070907. Pull-down assays revealed that biotinylated (arylthio)cyclopentenone (GIF-0643-biotin) and other biotin-bound cyclopentenones bind to PPAR gamma. The results also indicate that the GIF-0643-biotin-PPAR gamma complex is localized to the nucleus. Moreover, retinoid X receptor-alpha (RXR) co-precipitated with the GIF-0643-biotin-PPAR gamma complex, indicating that (arylthio)cyclopentenone can activate PPAR gamma-RXR heterodimers. These findings suggest that (arylthio)cyclopentenone derivatives prevent excitotoxicity by modulating gene expression via activation of the PPAR gamma-RXR hetrodimer.