Nurr1 overexpression in the primary motor cortex alleviates motor dysfunction induced by intracerebral hemorrhage in the striatum in mice.

Hemorrhage-induced injury of the corticospinal tract (CST) in the internal capsule (IC) causes severe neurological dysfunction in both human patients and rodent models of intracerebral hemorrhage (ICH). A nuclear receptor Nurr1 (NR4A2) is known to exert anti-inflammatory and neuroprotective effects in several neurological disorders. Previously we showed that Nurr1 ligands prevented CST injury and alleviated neurological deficits after ICH in mice. To prove direct effect of Nurr1 on CST integrity, we examined the effect of Nurr1 overexpression in neurons of the primary motor cortex on pathological consequences of ICH in mice. ICH was induced by intrastriatal injection of collagenase type VII, where hematoma invaded into IC. Neuron-specific overexpression of Nurr1 was induced by microinjection of synapsin I promoter-driven adeno-associated virus (AAV) vector into the primary motor cortex. Nurr1 overexpression significantly alleviated motor dysfunction but showed only modest effect on sensorimotor dysfunction after ICH. Nurr1 overexpression also preserved axonal structures in IC, while having no effect on hematoma-associated inflammatory events, oxidative stress, and neuronal death in the striatum after ICH. Immunostaining revealed that Nurr1 overexpression increased the expression of Ret tyrosine kinase and phosphorylation of Akt and ERK1/2 in neurons in the motor cortex. Moreover, administration of Nurr1 ligands 1,1-bis(3'-indolyl)-1-(p-chlorophenyl)methane or amodiaquine increased phosphorylation levels of Akt and ERK1/2 as well as expression of glial cell line-derived neurotrophic factor and Ret genes in the cerebral cortex. These results suggest that the therapeutic effect of Nurr1 on striatal ICH is attributable to the preservation of CST by acting on cortical neurons.

Lithium Binaphtholate-Catalyzed Asymmetric Michael Reaction of Acrylamides.

Chiral lithium binaphtholates prepared from the corresponding binaphthols and lithium tert-butoxide effectively catalyze the asymmetric Michael additions of ketones to poorly reactive acrylamides. The lithium binaphtholate catalyst mediates ketone deprotonation and enantioselective carbon-carbon bond formation to the acrylamide to deliver the Michael adduct in good yield and enantioselectivity. A small excess of lithium tert-butoxide relative to the binaphthol successfully enolizes the ketone in the initial stage of the reaction to promote the Michael reaction. Computational analysis of the transition state suggested that the 3- and 3'-phenyl groups of the binaphtholate catalyst regulate the orientation of the lithium enolate and the subsequent approach of the acrylamide, leading to superior enantioselectivity.

Enantioselective and Chemoselective Phosphine Oxide-catalyzed Aldol Reactions of N-Unprotected Cyclic Carboxyimides.

Asymmetric catalytic transformations of N-unprotected cyclic carboxyimides such as succinimides, hydantoins, oxazolidinediones, and glitazones, is a powerful way of directly accessing variety of biologically valuable chiral compounds. Herein, a bis(trichlorosilyl) nucleophilic intermediate formed from cyclic carboxyimides was reacted with aldehydes via (S)-SEGPHOS dioxide (SEGPHOSO), proceeding the aldol reaction in highly enantioselective fashion through a cyclic transition state. Furthermore, N-unprotected carboxyimides were chemoselectively activated, even in the presence of N-alkylated carboxyimides, to undergo stereoselective and chemoselective aldol reactions via in situ silicon tetrachloride activation. The functionalized cyclic carboxyimides is readily derived to the several synthetic units derivatization to various chiral building blocks without unnecessary protection/deprotection steps.

Arteperoxides A-C, tris-normonoterpene-sesquiterpene conjugates with peroxide-bridges from Artemisia judaica exhibiting antiosteoclastogenic activity.

Antiosteoclastogenic-guided screening was conducted with 120 extracts of the medicinal plants collected in Egypt that led to the selection of Artemisia judaica L. (Asteraceae). Three undescribed davanone-related terpenoids, arteperoxides A-C, were isolated from the extract with two known derivatives, hydroxydavanone and davana acid. Structural analysis revealed that arteperoxides A-C were tris-normonoterpene-sesquiterpene conjugates with peroxide bridges. Although davanone derivatives with peroxides, such as a hydroperoxyl and peroxyhemiketal groups, have been isolated from Artemisia species, arteperoxides A-C are the first variations observed to contain peroxide bridges between two terpene-derived units. The absolute configurations of arteperoxides A and B were studied based on their spectroscopic data compared with those of the semisynthetic analogs that have ether linkages. The natural and synthetic compounds were tested for the antiosteoclastogenic activity, and arteperoxide C and hydroxydavanone were more potent than other compounds at 20 µM.

Combinatorial screening for therapeutics in ATTRv amyloidosis identifies naphthoquinone analogues as TTR-selective amyloid disruptors.

Hereditary ATTR amyloidosis is caused by the point mutation in serum protein transthyretin (TTR) that destabilizes its tetrameric structure to dissociate into monomer. The monomers form amyloid fibrils, which are deposited in peripheral nerves and organs, resulting in dysfunction. Therefore, a drug that dissolves amyloid after it has formed, termed amyloid disruptor, is needed as a new therapeutic drug. Here, we first established a high throughput screening system to find TTR interactors from the LOPAC1280 compound library. Among the hit compounds, thioflavin T-based post-treatment assay determined lead compounds for TTR amyloid disruptors, NSC95397 and Gossypol, designated as B and R, respectively. Because these compounds have naphthoquinone-naphthalene structures, we tested 100 naphthoquinone derivatives, and found 10 candidate compounds that disrupted TTR amyloid. Furthermore, to determine whether these 10 compounds are selective for TTR amyloid, we evaluated them against beta-amyloid (Aß1-42). We found two compounds that were selective for TTR and did not disrupt Aß-derived amyloid. Therefore, we succeeded in identifying TTR-selective amyloid disruptors, and demonstrated that naphthoquinone compounds are useful structures as amyloid disruptors. These findings contribute to the on-going efforts to discover new therapeutic tools for TTR amyloidosis.

A Nurr1 ligand C-DIM12 attenuates brain inflammation and improves functional recovery after intracerebral hemorrhage in mice.

We have previously reported that amodiaquine, a compound that binds to the ligand-binding domain of a nuclear receptor Nurr1, attenuates inflammatory responses and neurological deficits after intracerebral hemorrhage (ICH) in mice. 1,1-Bis(3'-indolyl)-1-(p-chlorophenyl)methane (C-DIM12) is another Nurr1 ligand that recognizes a domain of Nurr1 different from the ligand-binding domain. In the present study, mice were treated daily with C-DIM12 (50 or 100 mg/kg, p.o.) or amodiaquine (40 mg/kg, i.p.), or twice daily with 1400 W (20 mg/kg, i.p.), an inducible nitric oxide synthase (iNOS) inhibitor, from 3 h after ICH induction by microinjection of collagenase into the striatum. C-DIM12 improved the recovery of neurological function and prevented neuron loss in the hematoma, while suppressed activation of microglia/macrophages and expression of inflammatory mediators interleukin-6 and CC chemokine ligand 2. In addition, C-DIM12 as well as amodiaquine preserved axonal structures in the internal capsule and axonal transport function. We also found that C-DIM12 and amodiaquine suppressed the increases of iNOS mRNA expression after ICH. Moreover, 1400 W improved neurological function and prevented neuron loss, activation of microglia/macrophages and axonal transport dysfunction. These results suggest that suppression of iNOS induction contributes to several features of the therapeutic effects of Nurr1 ligands.

Isolation, Synthesis, and Structure-Activity Relationship Study on Daphnane and Tigliane Diterpenes as HIV Latency-Reversing Agents.

Three new diterpenes, stellejasmins A (1) and B (2) and 12-O-benzoylphorbol-13-heptanoate (3), were isolated from the roots of Stellera chamaejasme L. The structures of 1-3 were elucidated by extensive NMR and mass spectroscopic analyses. Compounds 1 and 2 are the first derivatives containing a hydroxy group at C-2 in the family of daphnane and tigliane diterpenes. The presence of a chlorine atom in 1 is unique in the plant metabolite. Compound 3 has an odd-number acyl group, which is biosynthetically notable. Human immunodeficiency virus (HIV) LTR-driven transcription activity was tested with 1-3 and 17 known diterpenes isolated from S. chamaejasme L. and Wikstroemia retusa A.Gray. Among these, gnidimacrin (4), stelleralide A (5), and wikstroelide A (20) were highly potent, with EC50 values of 0.14, 0.33, and 0.39 nM, respectively. The structure-activity relationship (SAR) was investigated using 20 natural and eight synthetic diterpenes. This is the first SAR study on natural daphnane and tigliane diterpenes.

Molecular recognition of a single-chain Fv antibody specific for GA-pyridine, an advanced glycation end-product (AGE), elucidated using biophysical techniques and synthetic antigen analogues.

Advanced glycation end-products (AGEs) are a heterogeneous group of compounds formed by non-enzymatic reaction between reducing-sugar and Arg/Lys in proteins and are involved in various diabetic complications. GA-pyridine is derived from glycolaldehyde and is one of the most cytotoxic AGEs. Here, we established a single-chain Fv (scFv) antibody against GA-pyridine, 73MuL9-scFv, and examined the details of its specificity and antigen recognition by using various techniques involving biophysics, chemical biology and structural biology. We also synthesized several compounds that differ slightly in regard to the position and number of GA-pyridine substituent groups, and revealed that GA-pyridine was specifically bound to 73MuL9-scFv. Thermodynamic analysis revealed that the association of GA-pyridine to 73MuL9-scFv was an exothermic and enthalpy driven reaction, and thus that the antigen recognition involved multiple specific interactions. Crystallographic analysis of the Fv fragment of 73MuL9-scFv revealed that several CH-π and hydrogen bond interactions took place between the Fv-fragment and GA-pyridine, which was consistent with the results of thermodynamic analysis. Further studies using 73MuL9-scFv as a tool to clarify the relevance of GA-pyridine to diabetic complications are warranted.

Melinjo seed extract increases adiponectin multimerization in physiological and pathological conditions.

Melinjo seed extract (MSE) contains large amounts of polyphenols, including dimers of trans-resveratrol (e.g. gnetin C, L, gnemonoside A, B and D), and has been shown to potentially improve obesity. However, there is no clinical evidence regarding the anti-obesity effects of MSE, and its mechanisms are also unclear. We investigated the hypothesis that MSE supplementation increases the adiponectin (APN) multimerization via the up-regulation of disulfide bond A oxidoreductase-like protein (DsbA-L) under either or both physiological and obese conditions. To investigate the effect of MSE on the physiological condition, 42 healthy young volunteers were enrolled in a randomized, double-blind placebo-controlled clinical trial for 14 days. The participants were randomly assigned to the MSE 150 mg/day, MSE 300 mg/day or placebo groups. Furthermore, in order to investigate the effect of MSE on APN levels under obese conditions, we administered MSE powder (500 or 1000 mg/kg/day) to control-diet- or high-fat-diet (HFD)-fed C57BL/6 mice for 4 weeks. All participants completed the clinical trial. The administration of MSE 300 mg/day was associated with an increase in the ratio of HMW/total APN in relation to the genes regulating APN multimerization, including DsbA-L. Furthermore, this effect of MSE was more pronounced in carriers of the DsbA-L rs191776 G/T or T/T genotype than in others. In addition, the administration of MSE to HFD mice suppressed their metabolic abnormalities (i.e. weight gain, increased blood glucose level and fat mass accumulation) and increased the levels of total and HMW APN in serum and the mRNA levels of ADIPOQ and DsbA-L in adipose tissue. The present study suggests that MSE may exert beneficial effects via APN multimerization in relation to the induction of DsbA-L under both physiological and obese conditions.

Lewis Base-Catalyzed Enantioselective Conjugate Reduction of ß,ß-Disubstituted α,ß-Unsaturated Ketones with Trichlorosilane: E/Z-Isomerization, Regioselectivity, and Synthetic Applications.

The chiral bisphosphine dioxide-catalyzed asymmetric conjugate reduction of acyclic ß,ß-disubstituted α,ß-unsaturated ketones with trichlorosilane affords saturated ketones having a stereogenic carbon center at the carbonyl ß-position with high enantioselectivities. Because the E/Z-isomerizations of enone substrates occur concomitantly, reduction products with the same absolute configurations are obtained from either (E)- or (Z)-enones. Conjugate reduction is accelerated in the presence of an electron-rich aryl group at the ß-position of the enone owing to its carbocation-stabilizing ability. Computational studies were also conducted in order to elucidate the origin of the observed enantioselectivity. The regio- and enantioselective reductions of dienones were realized and applied to the syntheses of ar-turmerone, turmeronol A, mutisianthol, and jungianol, which are optically active sesquiterpenes.

Phosphine Oxide-Catalyzed Asymmetric Aldol Reactions and Double Aldol Reactions.

Chiral phosphine oxides successfully catalyze asymmetric cross-aldol reactions of various carbonyl compounds in a highly enantioselective manner. The phosphine oxide catalysts coordinate to chlorosilanes to form chiral hypervalent silicon complexes in situ, which activate both aldol donors and acceptors, thus realizing cross-aldol reactions between a ketone and an aldehyde, between two aldehydes, between two ketones, and of 2,6-diketones. The use of phosphine oxide catalysis can be further extended to achieve the first catalytic enantioselective double aldol reactions, realizing one-pot stereoselective construction of up to four stereogenic centers.

Stereoselective Synthesis of 2-Fluoro-1,3-Diols via Lithium Binaphtholate-Catalyzed Aldol-Tishchenko Reaction.

Lithium binaphtholate, readily prepared from ( R)-3,3'-I2-BINOL and lithium tert-butoxide, efficaciously catalyzed the enantioselective aldol-Tishchenko tandem reaction of α-fluoroketones with aldehydes, achieving the enantioselective synthesis of 2-fluoro-1,3-diols with three contiguous stereogenic centers. Kinetic studies revealed that the aldol reaction and the subsequent hemiacetal formation are in equilibrium under the reaction conditions and that the lithium binaphtholate catalyst selectively promotes hydride shift of one of the eight stereoisomers to produce 2-fluoro-1,3-diols containing a tetrasubstituted fluorinated carbon center.

Catalytic Enantioselective Aldol Reactions of Unprotected Carboxylic Acids under Phosphine Oxide Catalysis.

The first catalytic enantioselective aldol reaction of various unprotected carboxylic acids is described. In the presence of a chiral bis(phosphine oxide) as a Lewis base catalyst, carboxylic acids were activated with silicon tetrachloride to form the corresponding bis(trichlorosilyl)enediolates in situ, which subsequently underwent an aldol reaction with an aldehyde or a ketone to produce ß-hydroxycarboxylic acids in high enantioselectivities of up to 92 % ee.

Asymmetric Aldol/Vinylogous Aldol/Cyclization Reaction Using Phosphine Oxide Catalysts.

Chiral phosphine oxide sequentially activates silicon tetrachloride and trichlorosilyl enol ethers to facilitate asymmetric aldol/vinylogous aldol reaction of 4-methoxy-3-penten-2-one and conjugated aldehydes in a highly enantioselective fashion, and the subsequent cyclization produced optically active 2,6-disubstituted 2,3-dihydro-4-pyranones bearing stereogenic centers at a remote position in a single operation.

Stereoselective Synthesis of Nitrogen-Containing Compounds from Enamines.

The domino reaction of enamines, electrophiles (N-sulfonylimines, N-tosylisocyanate, or diethyl azodicarboxylate), and trichlorosilane provided trans-amines (trans/cis = > 99:1 to 96:4). Meanwhile, the sequential imino ene-type reaction of enamines and electrophiles/NaBH3CN reduction afforded cis-amines (trans/cis = 1:>99 to 15:85). The reversal of selectivity is discussed on the basis of diastereofacial selection of the plausible iminium ion intermediates. For the domino reaction of cyclic enamines and cyclic imines, high enantioselectivity (er = 95.7:4.3 to 99.9:0.1) was achieved by utilizing chiral Lewis base catalysts.

Sequential Catalysis of Phosphine Oxide for Stereoselective Synthesis of Stereopentads.

An efficient method for accessing enantiomerically pure stereopentads via a catalytic asymmetric sequential aldol reaction has been developed for the first time. The enantioselective sequential aldol reaction produces a wide range of chiral stereopentad precursors in good yields with excellent enantioselectivities. The key to success is the use of the sequential catalytic system involving a chiral phosphine oxide catalyst and trichlorosilyl triflate.

Indoxyl sulfate potentiates skeletal muscle atrophy by inducing the oxidative stress-mediated expression of myostatin and atrogin-1.

Skeletal muscle atrophy, referred to as sarcopenia, is often observed in chronic kidney disease (CKD) patients, especially in patients who are undergoing hemodialysis. The purpose of this study was to determine whether uremic toxins are involved in CKD-related skeletal muscle atrophy. Among six protein-bound uremic toxins, indole containing compounds, indoxyl sulfate (IS) significantly inhibited proliferation and myotube formation in C2C12 myoblast cells. IS increased the factors related to skeletal muscle breakdown, such as reactive oxygen species (ROS) and inflammatory cytokines (TNF-α, IL-6 and TGF-ß1) in C2C12 cells. IS also enhanced the production of muscle atrophy-related genes, myostatin and atrogin-1. These effects induced by IS were suppressed in the presence of an antioxidant or inhibitors of the organic anion transporter and aryl hydrocarbon receptor. The administered IS was distributed to skeletal muscle and induced superoxide production in half-nephrectomized (1/2 Nx) mice. The chronic administration of IS significantly reduced the body weights accompanied by skeletal muscle weight loss. Similar to the in vitro data, IS induced the expression of myostatin and atrogin-1 in addition to increasing the production of inflammatory cytokines by enhancing oxidative stress in skeletal muscle. These data suggest that IS has the potential to accelerate skeletal muscle atrophy by inducing oxidative stress-mediated myostatin and atrogin-1 expression.

Stereoselective Synthesis of Highly Functionalized 2,3-Dihydro-4-pyranones Using Phosphine Oxide as Catalyst.

2,3-Dihydro-4-pyranones were synthesized stereoselectively using a chiral phosphine oxide as the catalyst. The phosphine oxide sequentially activated silicon tetrachloride and promoted the double aldol reaction of 4-methoxy-3-buten-2-one with aldehydes. Subsequent stereoselective cyclization afforded the corresponding highly functionalized 2,3-dihydro-4-pyranones bearing three contiguous chiral centers in good yields and with high diastereo- and enantioselectivities.

Concise Asymmetric Construction of C2 -symmetric 1,9-Diarylnonanoids Using a Hypervalent Silicon Complex: Total Synthesis of (-)-Ericanone.

By using a phosphine oxide-catalyzed enantioselective double aldol reaction, we achieved the concise construction of C2 -symmetric 1,9-diarylnonanoids, enabling the synthesis of (-)-ericanone from p-hydroxybenzaldehyde in 6 steps with 65 % overall yield. The enantioselective double aldol reaction is useful for establishing C2 -symmetric 1,9-diaryl-3,7-dihydroxy-5-nonanones with a single operation. Furthermore, the use of o-nosyl-protected p-hydroxybenzaldehyde and a 4,4'-disubstituted BINAP dioxide catalyst dramatically improved the reactivity and selectivity in the double aldol reaction, enabling the total synthesis of (-)-ericanone with high yield and with excellent enantiopurity.