Fas-associated factor 1 induces the accumulation of α-synuclein through autophagic suppression in dopaminergic neurons.

Impairment of protein clearance mechanisms leads to α-synuclein accumulation in dopaminergic neurons, contributing to the pathogenesis of Parkinson's disease (PD). Based on the finding that Fas-associated factor 1 (FAF1), a positive modulator of PD, colocalizes with α-synuclein in PD patient brains, we investigated the existence of pathological interplay between FAF1 and α-synuclein. Monomeric and high-molecular-weight forms of α-synuclein were increased in FAF1-overexpressing SH-SY5Y cells. In particular, α-synuclein turnover was accelerated by genetic depletion of FAF1 in SH-SY5Y cells. Therefore, we questioned whether FAF1 is involved in the α-synuclein clearance process. Autophagy inhibitors, but not proteasome inhibitors, restored concurrent attenuation of α-synuclein expression by FAF1 depletion in SH-SY5Y cells. Moreover, we found alterations in autophagy markers in SH-SY5Y cells caused by FAF1 overexpression, indicating that FAF1 disturbed α-synuclein clearance through the autophagy-lysosome pathway. Indeed, FAF1 activated the mammalian target of rapamycin (mTOR) pathway, subsequently suppressing autophagosome formation. Consistently, α-synuclein-mediated mitochondrial dysfunction was observed in FAF1-overexpressing SH-SY5Y cells. Furthermore, FAF1 overexpression using stereotaxic injection of adeno-associated virus led to α-synuclein accumulation and autophagy dysregulation in the PD model mice. Taken together, our results reveal a novel role for FAF1: that of a negative regulator of autophagic α-synuclein clearance.

Novel colchicine derivatives enhance graft survival after transplantation via suppression of T-cell differentiation and activity.

Immunosuppressants are crucial in organ transplantation but their side effects are a trade-off for long-term use. Colchicine has been shown to be effective in various diseases, albeit with many side effects. To enhance the immunosuppressive effects of colchicine, in addition to minimizing its side effects, we attempted to synthesize new colchicine derivatives (KR compounds). In rat cardiac and pancreatic islet allograft, long-term graft survival was identified in KR compound-treated groups. The use of cyclosporine A (CsA) or colchicine inhibited the CD3+ and CD4+ T-cell proliferation, whereas KR compounds inhibited the CD8+ T cells as well as CD4+ T cells. KR compounds reduced the apoptosis, interleukin-2 receptor expression, and signal transducer and activator of transcription 3 phosphorylation more than CsA. These results indicate that KR compounds have a potential therapeutic value as novel agents for prevention of graft deterioration by allograft of rejection.

Design and synthesis of fluorescent and biotin tagged probes for the study of molecular actions of FAF1 inhibitor.

To study the molecular action of ischemic Fas-mediated cell death inhibitor, we prepared fluorescent-tagged and biotin-tagged probes of the potent inhibitor, KR-33494, of ischemic cell death. We used the molecular modeling technique to find the proper position for attaching those probes with minimum interference in the binding process of probes with Fas-mediated cell death target, FAF1.

Subacute toxicity evaluation of KR-33493, FAF1 inhibitor for a new anti-parkinson's disease agent, after oral administration in rats and dogs.

KR33493, a newly developed FAS-associated factor 1 (FAF1) inhibitor for Parkinson's disease, is being evaluated in a Phase I clinical trial. In the present study, the subchronic toxicity of KR33493 in Sprague-Dawley (SD) rats and beagle dogs was investigated at various oral doses for 28 and 14 days, respectively. During the study, food consumption, body weights, organ weights, gross findings, and mortality were examined; and ophthalmoscopy, electrocardiography, hematology, serum biochemistry, urinalysis, histopathology, and toxicokinetics were performed. In rats, weight gain decreased in both sexes at 500 mg/kg/day, with no significant differences. In dogs, some significant differences compared with the control were found during the trial; however, at the end of recovery periods, these were no longer observed and there was no dose correlation. Some histopathological findings were observed, but these were considered as incidental changes. Since no other significant changes were observed, doses above 500 and 1000 mg/kg KR33493 in rat and dogs, respectively, caused no observed adverse effects. Therefore, based on these results, the Phase 1 clinical trial for KR33493 was approved by the Korean Food & Drug Administration.

Accumulation of the parkin substrate, FAF1, plays a key role in the dopaminergic neurodegeneration.

This study reports the physical and functional interplay between Fas-associated factor 1 (FAF1), a death-promoting protein, and parkin, a key susceptibility protein for Parkinson's disease (PD). We found that parkin acts as an E3 ubiquitin ligase to ubiquitinate FAF1 both in vitro and at cellular level, identifying FAF1 as a direct substrate of parkin. The loss of parkin function due to PD-linked mutations was found to disrupt the ubiquitination and degradation of FAF1, resulting in elevated FAF1 expression in SH-SY5Y cells. Moreover, FAF1-mediated cell death was abolished by wild-type parkin, but not by PD-linked parkin mutants, implying that parkin antagonizes the death potential of FAF1. This led us to investigate whether FAF1 participates in the pathogenesis of PD. To address this, we used a gene trap mutagenesis approach to generate mutant mice with diminished levels of FAF1 (Faf1(gt/gt)). Using the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-treated mouse model of PD, we found that FAF1 accumulated in the substantia nigra pars compacta (SNc) of MPTP-treated PD mice, and that MPTP-induced dopaminergic cell loss in the SNc was significantly attenuated in Faf1(gt/gt) mice versus Faf1(+/+) mice. MPTP-induced reduction of locomotor activity was also lessened in Faf1(gt/gt) mice versus Faf1(+/+) mice. Furthermore, we found that FAF1 deficiency blocked PD-linked biochemical events, including caspase activation, ROS generation, JNK activation and cell death. Taken together, these results suggest a new role for FAF1: that of a positive modulator for PD.

Quantitative determination of enzalutamide, an anti-prostate cancer drug, in rat plasma using liquid chromatography-tandem mass spectrometry, and its application to a pharmacokinetic study.

This report details a method using liquid chromatography-tandem mass spectrometry (LC-MS/MS) that allows one to determine the concentration of an atypical anticancer drug, enzalutamide, in rat plasma. Specifically, this method involves the addition of an acetonitrile and bicalutamide (internal standard) solution to plasma samples. Following centrifugation of this mixture, an aliquot of the supernatant was directly injected into the LC-MS/MS system. Separation was achieved using a column packed with octadecylsilica (5 µm, 2.1 × 50 mm) with 10 mM ammonium acetate in acetonitrile as the mobile phase; detection was accomplished using MS/MS by multiple-reaction monitoring via an electrospray ionization source. This method demonstrated a linear standard curve (r = 0.997) over a concentration range of 0.001-1 µg/mL, as well as an intra- and inter-assay precision of 2.7 and 5.1%, respectively, and an accuracy range from 100.8 to 105.6%. The lower limit of quantification was 1.0 ng/mL in 50 µL of rat plasma sample. We also demonstrated that this analytical method could be successfully applied to the pharmacokinetic study of enzalutamide in rats.

Discovery of non-LBD inhibitor for androgen receptor by structure-guide design.

In this study, we synthesized the BF-3 binding small molecules, a series of pyridazinone-based compounds, as a novel class of non-LBP antiandrogens for treating prostate cancer by inhibiting androgen receptor. The new class compound was discovered to inhibitor the viability of AR-dependent human prostate LNCap cells and AR activity combining with the computational method. It showed a good physicochemical and PK property.

Pharmacological Intervention Targeting FAF1 Restores Autophagic Flux for α-Synuclein Degradation in the Brain of a Parkinson's Disease Mouse Model.

α-Synuclein accumulation is implicated in the pathogenesis of neurodegenerative diseases, including Parkinson's disease (PD). Previously, we reported that Fas-associated factor 1 (FAF1), which plays a role in PD pathogenesis, potentiates α-synuclein accumulation through autophagy impairment in dopaminergic neurons. In this study, we show that KM-819, a FAF1-targeting compound, which has completed phase I clinical trials, interferes with α-synuclein accumulation in the mouse brain, as well as in human neuronal cells (SH-SY5Ys). KM-819 suppressed the accumulation of monomeric, oligomeric, and aggregated forms of α-synuclein in neuronal cells. Furthermore, KM-819 restored the turnover rate of α-synuclein in FAF1-overexpressing SH-SY5Y cells, implicating KM-819-mediated reconstitution of the α-synuclein degradative pathway. In addition, KM-819 reconstituted autophagic flux in FAF1-transfected SH-SY5Y cells, also suppressing α-synuclein-induced mitochondrial dysfunction. Moreover, oral administration of KM-819 also interfered with α-synuclein accumulation in the midbrain of mice overexpressing FAF1 via an adeno-associated virus system. Consistently, KM-819 reduced α-synuclein accumulation in both the hippocampus and the midbrain of human A53T α-synuclein transgenic mice. Collectively, these data imply that KM-819 may have therapeutic potential for patients with PD.

Vitamin C deficiency attenuates liver fibrosis by way of up-regulated peroxisome proliferator-activated receptor-gamma expression in senescence marker protein 30 knockout mice.

UNLABELLED: Senescence marker protein 30 (SMP30), an important aging marker molecule that is highly expressed in the liver, has been known to protect hepatocytes from apoptosis by the synthesis of vitamin C. To explore the function of SMP30 in liver fibrosis, the effect of SMP30 deficiency on liver fibrosis was investigated in SMP30 knockout (KO) mice. Moreover, the in vivo results were further confirmed by way of hepatic stellate cell (HSC) isolation. We demonstrated that carbon tetrachloride (CCl(4))-induced liver fibrosis and the nuclear translocation of p-Smad2/3, the immediate downstream of transforming growth factor beta (TGF-beta), were significantly inhibited in the liver of SMP30 KO mice compared with wildtype (WT) mice. We also confirmed that both WT and SMP30 KO HSCs did not express SMP30. Finally, we further confirmed that up-regulation of peroxisome proliferator-activated receptor-gamma (PPAR-gamma) caused by a lack of vitamin C was the pivotal factor in the mechanisms for attenuated liver fibrosis of SMP30 KO mice, and feeding with vitamin C restored CCl(4)-induced liver fibrosis in SMP30 KO mice. CONCLUSION: Vitamin C deficiency by SMP30 depletion attenuated liver fibrosis by way of up-regulated PPAR-gamma expression in SMP30 KO mice. Our results provide, for the first time, the possible mechanisms underlying inhibition of HSC activation associated with vitamin C and PPAR-gamma up-regulation in liver fibrosis of SMP30 KO mice.

Discovery of new inhibitor for PDE3 by virtual screening.

In this work, we tried to find a new scaffold for a PDE3 using virtual screening for the obesity treatment. We first analyzed structural features for the known PDE3 inhibitors based on the PDE3B-ligand complex structure, and then carried out a docking study based on PDE3B 3D structure. We obtained a compound as potent PDE3 inhibitor stimulating lipolysis in murine adipocytes and human adipocytes.

Synthesis and SAR investigations of novel 2-arylbenzimidazole derivatives as melanin-concentrating hormone receptor 1 (MCH-R1) antagonists.

Compounds containing 2-arybenzimidazole ring systems linked to arylpiperidines were synthesized and evaluated as MCH-R1 antagonists. The results of structure-activity relationship studies led to the identification of compound 4c as a potent MCH-R1 antagonist (IC(50)=1 nM). This compound also has good metabolic stability, and favorable pharmacokinetic and brain penetration properties. However 4c was found to be potent inhibitor of the hERG potassium channel.

Discovery of ß-aminoacyl containing thiazolidine derivatives as potent and selective dipeptidyl peptidase IV inhibitors.

A series of ß-aminoacyl containing thiazolidine derivatives was synthesized and evaluated for their ability to inhibit DPP-IV. Several thiazolidine derivatives with an acid moiety were found to be potent DPP-IV inhibitors. Among them, compound 2da is the most active in this series with an IC(50) value of 1 nM, and it showed excellent selectivity over DPP-IV related enzymes including DPP-2, DPP-8, and DPP-9. Compound 2da is chemically and metabolically stable, and showed no CYP inhibition, hERG binding or cytotoxicity. Compound 2db, an ester prodrug of 2da, showed good in vivo DPP-IV inhibition after oral administration in rat and dog models.

Synthesis and biological evaluation of 3-substituted-benzofuran-2-carboxylic esters as a novel class of ischemic cell death inhibitors.

A series of 3-substituted-benzofuran-2-carboxylic esters was synthesized and evaluated for biological activity as ischemic cell death inhibitors in H9c2 cells and rat primary cardiac myocytes under conditions of oxygen and glucose deprivation. The introduction of a sulfur atom at the three-position substituent of the benzofuran ring markedly improved ischemic cell death inhibitory potency. In particular, 3-[2-(4-nitro-phenylsulfanyl)-acetylamino]-benzofuran-2-carboxylic acid ester (10) (EC(50)=0.532 µM, cell death=6.18%) and 4-chloro-3-[3-(pyridin-2-ylsulfanyl)-propionylamino]-benzofuran-2-carboxylic ester (18) (EC(50)=0.557 µM, cell death=7.02%) were shown to be the most potent in this series of benzofuran analogs.

Identification of 4-[4-(4-fluoro-phenyl)-thiazol-2-ylamino]-2,6-dimethyl-phenol (KR-33749) as an inhibitor of 5-lipoxygenase with potent antiinflammatory activity.

BACKGROUND/AIM: To discover new 5-lipoxygenase (5-LO) inhibitors applicable to inflammation-related skin disease, we identified and examined antiinflammatory properties of a novel 5-LO inhibitor, KR-33749, in vitro and in vivo. METHODS: 5-LO enzyme activity was assayed using insect cell lysates overexpressing rat 5-LO. The leukotriene B(4) (LTB(4)) level was assayed in rat basophilic leukemia (RBL-1) cell line. Mouse ear edema was induced by topical application of arachidonic acid. Atopic dermatitis-like skin lesion was induced by topical application of 1-chloro-2,4-dinitrobenzene (DNCB) to NC/Nga mice. RESULTS: KR-33749 inhibited 5-LO activity with an IC(50) value of 70.5 +/- 6.0 nmol/l in parallel with LTB(4) inhibition in RBL-1 cells. The compound exhibited a >1,000-fold selectivity against 12-LO and 15-LO. KR-33749 showed in vivo protective effects against arachidonic acid-induced ear edema and DNCB-induced atopic dermatitis-like symptoms in NC/Nga mice. CONCLUSION: Our results show that KR-33749, a new 5-LO inhibitor exhibits potent antiinflammatory activities in vitro as well as in vivo.

Neurorestorative Effects of a Novel Fas-Associated Factor 1 Inhibitor in the MPTP Model: An [18F]FE-PE2I Positron Emission Tomography Analysis Study.

Fas-associated factor 1 (FAF1), a Fas-binding protein, is implicated in neuronal cell death in Parkinson's disease (PD). We examined the effects of a novel FAF1 inhibitor, KM-819, in dopaminergic neurons in a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mouse model using [18F]FE-PE2I positron emission tomography (PET). The MPTP model was generated with subacute MPTP treatment (20 mg/kg/day, i.p.) for 5 consecutive days in C57bl/6J mice. This study included three groups: the control group (treatment with saline only), the MPTP model group with KM-819 treatment (20 mg/kg/day p.o.) for 6 days, and the MPTP model group without KM-819 treatment. [18F]FE-PE2I PET studies were conducted in the same animals before and after MPTP with or without KM-819 treatment to monitor changes in striatal dopamine transporter activity indicated by non-displaceable binding potential (BPND) of [18F]FE-PE2I, and the expression levels of tyrosine hydroxylase were assessed using immunohistochemistry before and after KM-819 treatment. After MPTP injection, decreased striatal BPND was observed in the MPTP model group compared with the control group. Striatal BPND increased in the MPTP model group with KM-819 treatment, but not in the MPTP model group without KM-819 treatment. The tyrosine hydroxylase expression levels also significantly increased in the MPTP model group with KM-819 treatment compared with the control group. This study indicates that inhibition of the Fas-mediated cell death pathway by KM-819 has neurorestorative effects in striatal dopamine neurons in the MPTP model. Further studies would be needed to investigate the potential of KM-819 as a therapeutic drug for PD treatment.

Predictive models of Cannabinoid-1 receptor antagonists derived from diverse classes.

Chemical database design is an important consideration for screening processes in drug discovery. More specifically, classification of a diverse compound set deeply influences the validation and the predictive power of prediction model for the designing of novel compounds. In this work, we investigated the effect of the reasonable classification on the prediction model. We first collected the known Cannabinoid-1 receptor antagonists. Following this, we calculate the chemical descriptors in order to classify the collected compounds. Finally, we build two predictive models via the 3D-QSAR using different molecular alignment and the alignment independent Molecular Interaction Field models.

(2-Aryl-5-methylimidazol-4-ylcarbonyl)guanidines and (2-aryl-5-methyloxazol-4-ylcarbonyl)guanidines as NHE-1 inhibitors.

A series of (2-aryl-5-methylimidazol-4-ylcarbonyl)guanidines and (2-aryl-5-methyloxazol-4-ylcarbonyl)guanidines were synthesized and evaluated as NHE-1 inhibitors. The structure-activity relationships well matched those of furan derivatives, which were previously investigated. The (2,5-disubstituted)phenyl compounds showed better activities than the other analogues in both imidazole and oxazole compounds. Especially, 2-(2,5-dichlorophenyl)imidazole 52, and 2-(2-methoxy-5-chlorophenyl)imidazole 54 compounds exhibited potent cardioprotective efficacy both in vitro and in vivo as well as high NHE-1 inhibitory activities.

Potent neutralization of vacuolating cytotoxin (VacA) of Helicobacter pylori by immunoglobulins against the soluble recombinant VacA.

BACKGROUND: The recombinant vacuolating cytotoxin (rVacA) of Helicobacter pylori that retains native conformational epitopes was evaluated as a vaccine antigen for anti-H. pylori treatment. METHODS: s1m1 vacA gene fraction encoding the mature VacA protein was expressed as a soluble protein in E. coli at low temperature. The efficacy of anti-rVacA antibody against VacA or H. pylori was assessed in vitro using AGS cells and in vivo using a murine model. RESULTS: The rabbit antisera against rVacA completely neutralized the vacuolating activity and partially inhibited the cell death induced by VacA in AGS cells. Oral immunization of C57BL/6 mice with rVacA plus CpG-oligodeoxynucleotide (ODN) as an ajuvant stimulated specific anti-VacA antibody and mucosal immune responses which correlated with decreased systemic immune responses and gastric urease activities (p>0.05). CONCLUSION: The rVacA antigen possessing conformational epitopes may have potential as a vaccine component and may be useful in serological and histopathological analysis.

Influences of cytochrome b5 expression and its genetic variant on the activity of CYP2C9, CYP2C19 and CYP3A4.

The objective of the present study was to investigate the effects of cytochrome b5 (cytb5) on the drug metabolism catalyzed by CYP2C9, CYP2C19 and CYP3A4. Activities of CYP2C9, CYP2C19, and CYP3A4 were determined by using the prototypical substrates tolbutamide, omeprazole and midazolam, respectively. Cytb5 protein and mRNA contents showed large inter-individual variations with 11- and 6-fold range, respectively. All of three P450s showed an increased activity in proportion to the amount of cytb5 expression. Particularly, CYP3A4 showed the strongest correlation between cytb5 protein amount and the activity, followed by CYP2C9 and CYP2C19. The putative splicing variant, c.288G>A (rs7238987) was identified and was screened in 36 liver tissues by direct DNA sequencing. Liver tissues having a splicing variant exhibited unexpected sizes of cytb5 mRNA and a decreased expression tendency of cytb5 protein compared to the wild-type. A decreased activity in the metabolism of the CYP2C19 substrate omeprazole was observed in liver tissues carrying the splicing variant when compared to the wild-type Cytb5 (P < 0.05). The present results propose that different expression of cytb5 can cause variations in CYP mediated drug metabolism, which may explain, at least in part, the inter-individual difference in drug responses in addition to the CYP genetic polymorphisms.

Physiologically Based Pharmacokinetic Modeling Approach to Predict Drug-Drug Interactions With Ethionamide Involving Impact of Genetic Polymorphism on FMO3.

The widely used second-line antituberculosis drug ethionamide shows wide interindividual variability in its disposition; however, the relevant factors affecting this phenomenon have not been characterized. We previously reported the major contribution of flavin-containing monooxygenase 3 (FMO3) in the reductive elimination pathway of ethionamide. In this study, ethionamide metabolism was potentially inhibited by methimazole in vitro. The drug-drug interaction leading to methimazole affecting the disposition of ethionamide mediated by FMO3 was then quantitated using a bottom-up approach with a physiologically based pharmacokinetic framework. The maximum concentration (Cmax ) and area under the curve (AUC) of ethionamide were estimated to increase by 13% and 16%, respectively, when coadministered with methimazole. Subsequently, we explored the effect of FMO3 genetic polymorphism on metabolic capacity, by constructing 2 common functional variants, Lys158 -FMO3 and Gly308 -FMO3. Compared to the wild type, recombinant Lys158 -FMO3 and Gly308 -FMO3 variants significantly decreased the intrinsic clearance of ethionamide by 2% and 24%, respectively. Two prevalent functional variants of FMO3 were predicted to affect ethionamide disposition, with mean ratios of Cmax and AUC of up to 1.5 and 1.7, respectively, in comparison with the wild type. In comparing single ethionamide administration with the wild type, simulations of the combined effects of comedications and FMO3 genetic polymorphism estimated that the Cmax and AUC ratios of ethionamide increased up to 1.7 and 2.0, respectively. These findings suggested that FMO3-mediated drug-drug interaction and genetic polymorphism could be important determinants of interindividual heterogeneity in ethionamide disposition that need to be considered comprehensively to optimize the personalized dosing of ethionamide.