Kye Jung Shin

Expression of Liver X Receptor Correlates with Intrahepatic Inflammation and Fibrosis in Patients with Nonalcoholic Fatty Liver Disease

BackgroundLiver X receptor (LXR) is an oxysterol-activated nuclear receptor involved in the control of major metabolic pathways for cholesterol homeostasis and lipogenesis. Although the role of LXR in hepatic steatosis is well known, its correlation with intrahepatic inflammation and fibrosis has not been thoroughly studied. We investigated the association between LXRα, hepatic inflammation, and fibrosis, as well as its correlation with other intrahepatic lipid transporters in patients with nonalcoholic fatty liver disease (NAFLD).MethodsWe evaluated clinical characteristics including sex, age, body mass index, and laboratory findings from 40 NAFLD and 16 control patients. Immunohistochemical staining was carried out on liver biopsy samples from all patients.ResultsThe positive rate of LXRα expression was 30xa0% in the control group, 50xa0% in the NAFLD group, and 97xa0% in NASH groups. LXRα expression was positively correlated with not only the amount of intrahepatic fat, but also with intrahepatic inflammation and hepatic fibrosis. LXRα expression showed positive correlation with intrahepatic expression of ABCG5/8, CD36, and SREBP-1c. The expression of ABCA1, ABCG5/8, SREBP-1c, and CD36 was higher in NAFLD than in controls and there was no further increase in the NASH group. NPC1L1 was abundant in human liver. Expression of NPC1L1 was negatively correlated with intrahepatic inflammation and LXRα intensity.ConclusionLXR expression correlated with the degree of hepatic fat deposition, as well as with hepatic inflammation and fibrosis in NAFLD patients. Our research suggests that LXR is an attractive target for treatment and regulation of hepatic inflammation and fibrosis.

Synthesis and structure-activity relationships of tri-substituted thiazoles as RAGE antagonists for the treatment of Alzheimer's disease.

A series of thiazole derivatives were designed, and prepared to develop RAGE antagonist for the treatment of Alzheimers disease (AD). SAR studies were performed to optimize inhibitory activity on Aβ-RAGE binding. SAR studies showed that introducing an amino group at part A was essential for inhibitory activity on Aβ-RAGE binding. Compounds selected from Aβ-RAGE binding screening displayed inhibitory activity on Aβ transport across BBB. They also showed inhibitory activity against Aβ-induced NF-κB activation. These results indicated that our derivatives had a potential as therapeutic agent for the treatment of AD.

Antinociceptive curcuminoid, KMS4034, effects on inflammatory and neuropathic pain likely via modulating TRPV1 in mice

BACKGROUNDnCurcumin, the active ingredient of turmeric (Curcuma longa), has a wide range of beneficial effects including anti-inflammation and analgesia. However, poor bioavailability of curcumin hinders its clinical application. To overcome this limitation, we modified the structure of curcumin and synthesized new derivatives with favourable pharmacokinetic profiles. Recently, curcumin has been shown to have an antagonizing effect on transient receptor potential vanilloid type 1 (TRPV1) ion channels. We investigated the antinociceptive activity of KMS4034 which had the most favourable pharmacokinetics among the tested curcumin derivatives.nnnMETHODSnTo evaluate the mechanism of the antinociceptive effects of KMS4034, capsaicin (I(CAP))- and heat (I(heat))-induced currents in TRPV1 expressing HEK293 cells were observed after the application of KMS4034. Nociceptive behavioural measurement using the hot-plate test, formalin test, and chronic constriction injury (CCI) model were evaluated in mice. Also, calcitonin gene-related peptide (CGRP) was stained immunohistochemically in the L4/5 dorsal horns in mice with neuropathic pain.nnnRESULTSnI(CAP) (P<0.01) and I(heat) (P<0.05) of TRPV1 were significantly blocked by 10 μM KMS4034. Behaviourally, noticeable antinociceptive effects after 10 mg kg(-1) of KMS4034 treatment were observed in the first (P<0.05) and second phases (P<0.05) of the formalin and hot-plate tests. The mechanical threshold of CCI mice treated with 10 mg kg(-1) KMS4034 was significantly increased compared with control. Immunohistochemical CGRP expression was decreased in the lamina I-II of the lumbar dorsal horns in KMS4034-treated CCI mice compared with the control (P<0.05).nnnCONCLUSIONSnKMS4034 may be an effective analgesic for various pain conditions.

Small molecules that protect against β-amyloid-induced cytotoxicity by inhibiting aggregation of β-amyloid

Aggregated β-amyloid (Aβ) plays crucial roles in Alzheimers disease (AD) pathogenesis, therefore blockade of Aβ aggregation is considered as a potential therapeutic target. We designed and synthesized small molecules to reduce Aβ-induced cytotoxicity by inhibiting Aβ aggregation. The small molecules were screened via ThT, MTT, and cell-based cytotoxicity assay (Aβ burden assay). Selected compounds 1c, 1d, 1e, and 1f were then investigated by evaluating their effects on cognitive impairment of acute AD mice model. Learning and memory dysfunction by injection of Aβ(1-42) was recovered by administration of these molecules. Especially, 1d showed the best recovery activity in Y-maze task, object recognition task, and passive avoidance task with dose dependent manner. These results suggest that 1d has high potential as a therapeutic agent for AD.

Glucuronidation of a Sarpogrelate Active Metabolite Is Mediated by UDP-Glucuronosyltransferases 1A4, 1A9, and 2B4

Sarpogrelate is a selective serotonin 5-HT2A–receptor antagonist used to treat patients with peripheral arterial disease. This drug is rapidly hydrolyzed to its main metabolite (R,S)-1-[2-[2-(3–methoxyphenyl)ethyl]phenoxy]-3-(dimethylamino)-2-propanol (M-1), which is mainly excreted as a glucuronide conjugate. Sarpogrelate was also directly glucuronidated to an O-acyl glucuronide and a N-glucuronide by UDP-glucuronosyltransferases (UGTs) in human liver microsomes (HLMs). Since M-1 is pharmacologically more active than sarpogrelate, we examined glucuronidation of this metabolite in HLMs and characterized the UGTs responsible for M-1 glucuronidation. Diastereomers of O-glucuronide (SMG1 and SMG3) and a N-glucuronide (SMG2) were identified by incubation of M-1 with HLMs in the presence of uridine 5′-diphosphoglucuronic acid (UDPGA), and their structures were confirmed by nuclear magnetic resonance and mass spectrometry analyses. Two O-glucuronides were identified as chiral isomers: SMG1 as R-isomer and SMG3 as S-isomer. Using recombinant UGT enzymes, we determined that SMG1 and SMG3 were predominantly catalyzed by UGT1A9 and UGT2B4, respectively, whereas SMG2 was generated by UGT1A4. In addition, significant correlations were noted between the SMG1 formation rate and propofol glucuronidation (a marker reaction of UGT1A9; r = 0.6269, P < 0.0031), and between the SMG2 formation rate and trifluoperazine glucuronidation (a marker reaction of UGT1A4; r = 0.6623, P < 0.0015) in a panel of HLMs. Inhibition of SMG1, SMG2, and SMG3 formation by niflumic acid, hecogenin, and fluconazole further substantiated the involvement of UGT1A9, UGT1A4, and UGT2B4, respectively. These findings collectively indicate that UGT1A4, UGT1A9, and UGT2B4 are the major UGT isoforms responsible for glucuronidation of M-1, an active metabolite of sarpogrelate.

Induction of NQO1 and Neuroprotection by a Novel Compound KMS04014 in Parkinson's Disease Models

Parkinson’s disease (PD) is a progressive neurodegenerative disorder associated with a selective loss of the neurons containing dopamine (DA) in the substantia nigra pars compacta. Lines of evidence suggest that oxidative stress is a major factor contributing to the vulnerability of DA cells and that the enzyme NAD(P)H quinone oxidoreductase (NQO1) provides protection in these cells. In the present study, we report the synthesis of a novel compound KMS04014 and show that it induces NQO1 gene expression and protects DAergic neuronal cells in both cell culture and animal models of PD. In vitro, KMS04014 increased both mRNA and protein levels of NQO1 and induced nuclear translocation of Nrf2 in the DAergic neuronal cell line CATH.a. It also protected the cells against oxidative stress generated by tetrahydrobiopterin, 1-methyl-4-phenylpyridinium (MPP+), and H2O2. In vivo, KMS04014 attenuated the loss of tyrosine hydroxylase-immunopositive DAergic neurons in the substantia nigra and reduced degeneration of the nigral neurons and striatal fibers in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-treated mice, an animal model of PD. Taken together, KMS04014 may be utilized toward development of neuroprotective therapy for PD.

Synthesis and biological evaluation of 4-piperidinecarboxylate and 4-piperidinecyanide derivatives for T-type calcium channel blockers

To obtain selective and potent inhibitor for T-type calcium channel by ligand based drug design, 4-piperidinecarboxylate and 4-piperidinecyanide derivatives were prepared and evaluated for in vitro and in vivo activity against α(1G) calcium channel. Among them, several compounds showed good T-type calcium channel inhibitory activity and minimal off-target activity over hERG channel (% inhibition at 10 μM=61.85-71.99, hERG channel IC(50)=1.57 ± 0.14-4.98 ± 0.36 μM). Selected compound 31a was evaluated on SNL model of neuropathic pain and showed inhibitory effect on mechanical allodynia.

Discovery of potent and selective rhodanine type IKKβ inhibitors by hit-to-lead strategy

Regulation of NF-κB activation through the inhibition of IKKβ has been identified as a promising target for the treatment of inflammatory and autoimmune disease such as rheumatoid arthritis. In order to develop novel IKKβ inhibitors, we performed high throughput screening toward around 8000 library compounds, and identified a hit compound containing rhodanine moiety. We modified the structure of hit compound to obtain potent and selective IKKβ inhibitors. Throughout hit-to-lead studies, we have discovered optimized compounds which possess blocking effect toward NF-κB activation and TNFα production in cell as well as inhibition activity against IKKβ. Among them, compound 3q showed the potent inhibitory activity against IKKβ, and excellent selectivity over other kinases such as p38α, p38β, JNK1, JNK2, and JNK3 as well as IKKα.

Stereoselective Synthesis of 3-(1,3-Diarylallylidene)oxindoles via a Palladium-Catalyzed Tandem Reaction

We have developed an efficient three-component tandem reaction for the synthesis of 3-(1,3-diarylallylidene)oxindoles combining three palladium-catalyzed reactions: the Sonogashira, Heck, and Suzuki-Miyaura reactions. This method allows a stereoselective approach to each (E)- and (Z)-isomer by ligand change and controlling the reaction temperature.

Consecutive One-Pot versus Domino Multicomponent Approaches to 3-(Diarylmethylene)oxindoles

Based on consecutive one-pot conditions combining three palladium-catalyzed reactions (Sonogashira, Heck and Suzuki-Miyaura reactions), a more efficient domino multicomponent method has been successfully developed to access a wide variety of 3-(diarylmethylene)oxindoles. Microwave irradiation and use of a silver salt were the most important factors to achieve high yields and stereoselectivity.