Fluorine-19 magnetic resonance imaging probe for the detection of tau pathology in female rTg4510 mice.

Aggregation of tau into neurofibrillary tangles (NFTs) is characteristic of tauopathies, including Alzheimer's disease. Recent advances in tau imaging have attracted much attention because of its potential contributions to early diagnosis and monitoring of disease progress. Fluorine-19 magnetic resonance imaging (19 F-MRI) may be extremely useful for tau imaging once a high-quality probe has been formulated. In this investigation, a novel fluorine-19-labeling compound has been developed as a probe for tau imaging using 19 F-MRI. This compound is a buta-1,3-diene derivative with a polyethylene glycol side chain bearing a CF3 group and is known as Shiga-X35. Female rTg4510 mice (a mouse model of tauopathy) and wild-type mice were intravenously injected with Shiga-X35, and magnetic resonance imaging of each mouse's head was conducted in a 7.0-T horizontal-bore magnetic resonance scanner. The 19 F-MRI in rTg4510 mice showed an intense signal in the forebrain region. Analysis of the signal intensity in the forebrain region revealed a significant accumulation of fluorine-19 magnetic resonance signal in the rTg4510 mice compared with the wild-type mice. Histological analysis showed fluorescent signals of Shiga-X35 binding to the NFTs in the brain sections of rTg4510 mice. Data collected as part of this investigation indicate that 19 F-MRI using Shiga-X35 could be a promising tool to evaluate tau pathology in the brain.

Keto form of curcumin derivatives strongly binds to Aß oligomers but not fibrils.

The accumulation of ß-amyloid (Aß) aggregates in the brain occurs early in the progression of Alzheimer's disease (AD), and non-fibrillar soluble Aß oligomers are particularly neurotoxic. During binding to Aß fibrils, curcumin, which can exist in an equilibrium state between its keto and enol tautomers, exists predominantly in the enol form, and binding activity of the keto form to Aß fibrils is much weaker. Here we described the strong binding activity the keto form of curcumin derivative Shiga-Y51 shows for Aß oligomers and its scant affinity for Aß fibrils. Furthermore, with imaging mass spectrometry we revealed the blood-brain barrier permeability of Shiga-Y51 and its accumulation in the cerebral cortex and the hippocampus, where Aß oligomers were mainly localized, in a mouse model of AD. The keto form of curcumin derivatives like Shiga-Y51 could be promising seed compounds to develop imaging probes and therapeutic agents targeting Aß oligomers in the brain.

Amyloid imaging using fluorine-19 magnetic resonance imaging ((19)F-MRI).

The formation of senile plaques followed by the deposition of amyloid-ß is the earliest pathological change in Alzheimer's disease. Thus, the detection of senile plaques remains the most important early diagnostic indicator of Alzheimer's disease. Amyloid imaging is a noninvasive technique for visualizing senile plaques in the brains of Alzheimer's patients using positron emission tomography (PET) or magnetic resonance imaging (MRI). Because fluorine-19 ((19)F) displays an intense nuclear magnetic resonance signal and is almost non-existent in the body, targets are detected with a higher signal-to-noise ratio using appropriate fluorinated contrast agents. The recent introduction of high-field MRI allows us to detect amyloid depositions in the brain of living mouse using (19)F-MRI. So far, at least three probes have been reported to detect amyloid deposition in the brain of transgenic mouse models of Alzheimer's disease; (E,E)-1-fluoro-2,5-bis-(3-hydroxycarbonyl-4-hydroxy)styrylbenzene (FSB), 1,7-bis(4'-hydroxy-3'-trifluoromethoxyphenyl)-4-methoxycarbonylethyl-1,6-heptadiene3,5-dione (FMeC1, Shiga-Y5) and 6-(3',6',9',15',18',21'-heptaoxa-23',23',23'-trifluorotricosanyloxy)-2-(4'-dimethylaminostyryl)benzoxazole (XP7, Shiga-X22). This review presents the recent advances in amyloid imaging using (19)F-MRI, including our own studies.

Validation of a rapid one-step high sensitivity real-time quantitative PCR system for detecting major BCR-ABL1 mRNA on an International Scale.

BACKGROUND: Detection and quantitation of BCR-ABL1 transcripts are crucial for managing patients with chronic myeloid leukemia (CML). Although real-time quantitative polymerase chain reaction (RT-qPCR) can be measured on an International Scale (IS), this has not become fully universal. By using a WHO international standard panel established for calibrating secondary standards based on the IS, we have previously developed an RT-qPCR kit, ODK-1201, for quantification of major BCR-ABL1. RESULTS: In this study, the reliability of kit-specific conversion factor 1.12 was validated by exchanging patients' samples between three local clinical laboratories and a reference laboratory. The mean bias of the local method after IS conversion was 1.6 fold lower than the reference method. The clinically-useful sensitivity of the kit was further evaluated for monitoring patients with deep molecular response. Based on the correlation of the IS values between ODK-1201 and the reference laboratory method, the detection level of the kit was estimated as 0.0032 % BCR-ABL1 (IS). CONCLUSIONS: ODK-1201 is a highly sensitive one-step RT-qPCR system for detecting BCR-ABL1 on the IS in 2 h after RNA extraction, thus contributing to standardization of molecular monitoring in CML.

Curcumin derivative with the substitution at C-4 position, but not curcumin, is effective against amyloid pathology in APP/PS1 mice.

Recent evidence supports the amyloid cascade hypothesis that a pathological change of amyloid ß (Aß) in the brain is an initiating event in Alzheimer's disease (AD). Accordingly, modulating the abnormal Aß aggregation is considered a potential therapeutic target in AD. Curcumin, a low-molecular-weight polyphenol derived from the well-known curry spice turmeric, has shown favorable effects on preventing or treating AD pathology. The present study investigated the effects of curcumin and 2 novel curcumin derivatives, FMeC1 and FMeC2, on AD pathology in APPswe/PS1dE9 double transgenic mice. Mice fed a chow diet that contained FMeC1 for 6 months showed a reduction in insoluble Aß deposits and glial cell activity together with reduced cognitive deficits, compared to animals receiving a control diet or with curcumin or FMeC2 in their diet. Both curcumin and FMeC1 modulated the formation of Aß aggregates; however, only FMeC1 significantly attenuated the cell toxicity of Aß. These results indicate that FMeC1 may have potential for preventing AD.

A new diagnostic kit, ODK-1201, for the quantitation of low major BCR-ABL mRNA level in chronic myeloid leukemia: correlation of quantitation with major BCR-ABL mRNA kits.

The current first-line therapy of chronic myeloid leukemia (CML) is based on tyrosine kinase inhibitors. Diagnostic kits that are capable of identifying at least a 4.5 log reduction in the international scale % BCR-ABL/ABL (IS % BCR-ABL/ABL) are needed for use in the clinical evaluation of deeper molecular response to treatment and to determine the timing of dose selection or treatment interruption during the course of treatment. In this study, we evaluated the performance of a new diagnostic kit, ODK-1201, designed to be capable of performing reverse transcription and quantitative PCR in a single tube for the quantitation of major BCR-ABL mRNA. The kit demonstrated excellent assay performance (limit of detection 0.0007 %) and a broader detection range of BCR-ABL mRNA in peripheral blood compared to a commercially available kit for CML (Amp-CML). ODK-1201 was also shown to be as sensitive as Ipsogen and Molecular MD kits in the same assay. Results obtained in this study indicate evidences that ODK-1201 was capable of identifying at least a 4.5 log reduction in the IS % BCR-ABL/ABL.

Preferred features of a fluorine-19 MRI probe for amyloid detection in the brain.

Fluorine-19 magnetic resonance imaging (19F MRI) could be a promising approach for imaging amyloid deposition in the brain. However, the required features of a 19F MRI probe for amyloid detection remain unclear. In the present study, we investigated a series of compounds as potent 19F probes that could prevent the reduction in MR signal when bound to amyloid plaques in the brain. Each compound consists of styrylbenzoxazole as a core structure linked by a different length of polyethylene glycol (PEG) chain to one of three types of fluorine-labeled group: a trifluoroethoxy group, a hexafluoroisopropoxy group, or a 3',5'-bis(trifluoromethyl)benzylamino group. Among these compounds, 6-(3',6',9',15',18',21'-heptaoxa-23',23',23'-trifluoro tricosanyloxy)-2-(4'-dimethylaminostyryl)benzoxazole [compound 3b (m = 6)], which has a trifluoroethoxy group with seven ethylene glycol groups in the PEG chain, showed significant 19F MR signals in the brains of AßPPswe/PS1dE9 double-transgenic mice, but not wild-type mice. This suggested that compound 3b (m = 6) could be a useful 19F MRI probe for amyloid detection. Furthermore, this study identified the most effective length of PEG chain between the fluorine-labeled group and the core structure to ensure a strong MR signal when the probe is bound to amyloid plaques.

Sphingomyelinase C from Streptomyces sp. A9107: unusual primary structure for bacterial sphingomyelinase C.

A sphingomyelinase C (SMase) was identified in the culture supernatant of Streptomyces sp. A9107 (S-SMase). Although S-SMase seems to be a typical bacterial SMase, the primary structure of S-SMase was unusual for known bacterial SMase. The gene was functionally overexpressed in the culture medium of recombinant Rhodococcus erythropolis.

Role of Dlg5/lp-dlg, a membrane-associated guanylate kinase family protein, in epithelial-mesenchymal transition in LLc-PK1 renal epithelial cells.

Discs large homolog 5 (Dlg5) is a member of the membrane-associated guanylate kinase adaptor family of proteins, some of which are involved in the regulation of epithelial-to-mesenchymal transition (EMT). Dlg5 has been described as a susceptibility gene for Crohn's disease; however, the physiological function of Dlg5 is unknown. We show here that transforming growth factor-ß (TGF-ß)-induced EMT suppresses Dlg5 expression in LLc-PK1 cells. Depletion of Dlg5 expression by knockdown promoted the expression of the mesenchymal marker proteins, fibronectin and α-smooth muscle actin, and suppressed the expression of E-cadherin. In addition, activation of JNK and p38, which are stimulated by TGF-ß, was enhanced by Dlg5 depletion. Furthermore, inhibition of the TGF-ß receptor suppressed the effects of Dlg5 depletion. These observations suggest that Dlg5 is involved in the regulation of TGF-ßreceptor-dependent signals and EMT.