Design, Synthesis, and Monoamine Oxidase B Selective Inhibitory Activity of N-Arylated Heliamine Analogues.

Monoamine oxidase B (MAO-B) metabolizes monoamines such as dopamine regarding neural transmission and controls its level in the mammalian's brain. When MAO-B metabolizes dopamine abnormally, normal neurotransmission does not occur, and central nervous system disorders such as Parkinson's disease may develop. Although several MAO inhibitors have been developed, most of them have no selectivity between monoamine oxidase A (MAO-A) and MAO-B, or they work irreversibly against the enzyme. This report describes the first case of screening of N-arylated heliamine derivatives to develop novel MAO-B selective inhibitors that can be synthesized concisely by microwave-assisted Pd nanoparticle-catalyzed Buchwald-Hartwig amination. We discovered that the derivatives 4h, 4i, and 4j display inhibitory activity against MAO-B with IC50 values of 1.55, 13.5, and 5.08 µM, respectively.

Assessment of ATP8B1 Deficiency in Pediatric Patients With Cholestasis Using Peripheral Blood Monocyte-Derived Macrophages.

Progressive familial intrahepatic cholestasis type 1 (PFIC1), a rare inherited recessive disease resulting from a genetic deficiency in ATP8B1, progresses to liver failure. Because of the difficulty of discriminating PFIC1 from other subtypes of PFIC based on its clinical and histological features and genome sequencing, an alternative method for diagnosing PFIC1 is desirable. Herein, we analyzed human peripheral blood monocyte-derived macrophages (HMDM) and found predominant expression of ATP8B1 in interleukin-10 (IL-10)-induced M2c, a subset of alternatively activated macrophages. SiRNA-mediated depletion of ATP8B1 in IL-10-treated HMDM markedly suppressed the expression of M2c-related surface markers and increased the side scatter (SSC) of M2c, likely via impairment of the IL-10/STAT3 signal transduction pathway. These phenotypic features were confirmed in IL-10-treated HMDM from four PFIC1 patients with disease-causing mutations in both alleles, but not in those from four patients with other subtypes of PFIC. This method identified three PFIC1 patients in a group of PFIC patients undiagnosed by genome sequencing, an identical diagnostic outcome to that achieved by analysis of liver specimens and in vitro mutagenesis studies. In conclusion, ATP8B1 deficiency caused incomplete polarization of HMDM into M2c. Phenotypic analysis of M2c helps to identify PFIC1 patients with no apparent disease-causing mutations in ATP8B1.

Successful treatment with 4-phenylbutyrate in a patient with benign recurrent intrahepatic cholestasis type 2 refractory to biliary drainage and bilirubin absorption.

AIM: Benign recurrent intrahepatic cholestasis type 2 (BRIC2) is caused by mutations in ABCB11, a gene encoding the bile salt export pump (BSEP) that mediates biliary bile salt secretion, and presents with repeated intermittent cholestasis with refractory itching. Currently, no effective medical therapy has been established. We previously provided experimental and clinical evidence suggesting the therapeutic potential of 4-phenylbutyrate (4PB) for the cholestatic attacks of BRIC2. METHODS: After examining the potential therapeutic use of 4PB treatment by in vitro studies, a patient with BRIC2 was treated p.o. with 4PB at gradually increasing doses (200, 350, and 500 mg/kg per day) for 4 months. Biochemical, histological and clinical data were collected. RESULTS: The patient was diagnosed with BRIC2 because he had non-synonymous mutations (c.1211A>G [p.D404G] and 1331T>C [p.V444A]) in ABCB11, reduced hepatocanalicular expression of BSEP and low biliary bile salt concentrations. In vitro analysis showed that 4PB treatment partially restored the decreased expression of BSEP caused by p.D404G mutation. During the first 2 months of 4PB therapy at 200 and 350 mg/kg per day, the patient had no relief from his symptoms. No beneficial effect was observed after additional treatment with bilirubin absorption and endoscopic nasobiliary drainage. However, after starting treatment at a dose of 500 mg/kg per day, the patient's liver function tests and intractable itching were markedly improved. No apparent side-effects were observed during or after 4PB therapy. The symptoms relapsed within 1.5 months after cessation of 4PB therapy. CONCLUSION: 4PB therapy would have a therapeutic effect on the cholestatic attacks of BRIC2.

Isolation and analysis of amyloid-ß 1-42 monomer and oligomers in liquid droplets using an immunoaffinity membrane.

Monomeric molecules such as amyloid-ß can aggregate and transform into oligomeric and fibrous forms, which are implicated in the development and progression of Alzheimer's disease. Novel analytical techniques for the formation of oligomers are required to examine the neurotoxic amyloid-ß oligomers involving fibrils. After isolating amyloid-ß monomer 1-42 using a biotinylated antibody bound to membrane-immobilized avidin (immunoaffinity membrane), their masses were determined by MALDI-TOF MS. Fluorometric determination of more than 0.5µM of aggregated amyloid-ß in pipette droplets was performed after aggregation and dilution of 1mM amyloid-ß. Thus, large (>105nm) amyloid-ß oligomers in microliter volumes of fluids were isolated using the immunoaffinity membrane and quantitatively analyzed after removal of amyloid-ß monomers and small oligomers by non-denaturing electrophoresis. In addition, amyloid-ß oligomers were specifically isolated from a mixture of human plasma and aggregated amyloid-ß and then fluorometrically analyzed. Our results show that the combination of immunoaffinity membrane-binding and fluorescence determinations together with one drop analysis could be used to isolate and detect huge neurotoxic amyloid-ß oligomers such as fibrils in plasma samples.