Synthesis and biological activities of vitamin D3 derivatives with cyanoalkyl side chain at C-2 position

We synthesized and evaluated novel vitamin D3 derivatives with cyanoalkyl side chain at C-2 position on the basis of our previous research for 2α side chain which bears nitrogen atom-containing functional group. Through a study of X-ray co-crystal structures of human VDR and compound 3, we demonstrated that the 2α alkyl side chain in compound 3 shows a novel interaction in the complex of hVDR-LBD and ligand. This article is part of a Special Issue entitled '17th Vitamin D Workshop'.

Design and synthesis of 2α-(tetrazolylethyl)-1α,25-dihydroxyvitamin D3 as a high affinity ligand for vitamin D receptor

X-ray cocrystallographic studies of the human vitamin D receptor (hVDR)-[2α-(3-hydroxypropyl)-1α,25-dihydroxyvitamin D3 (O1C3)] complex showed that the terminal hydroxy group of the 2α-functional group of O1C3 formed a hydrogen bond with Arg274 in the ligand binding domain (LBD) of hVDR to stabilize the complex; therefore, O1C3 showed 3-times greater binding affinity for VDR than the natural hormone. Here, the effects of a heteroaromatic ring on binding to hVDR instead of the terminal OH group of O1C3 and also on preliminary biological activities were studied. We synthesized 2α-[2-(tetrazol-2-yl)ethyl]-1α,25(OH)2D3 (1a) and its regioisomer 2α-[2-(tetrazol-1-yl)ethyl]-1α,25(OH)2D3 (1b), in which 1a showed much higher hVDR binding affinity and greater osteocalcin promoter transactivation activity in human osteosarcoma (HOS) cells than those of 1b. X-ray cocrystallographic analysis of the hVDR-1a complex showed new hydrogen bond formation between one of the nitrogen atoms of the tetrazole ring and Arg274. This article is part of a Special Issue entitled '16th Vitamin D Workshop'.

Upregulation of non-β cell-derived vascular endothelial growth factor A increases small clusters of insulin-producing cells in the pancreas

Pancreatic β cell-derived vascular endothelial growth factor A (VEGF-A) contributes to normal β cell function. We therefore hypothesized that non-β cell-derived VEGF-A may affect its properties in adult mice.We generated transgenic mice expressing human VEGF-A (hVEGF-A) in a visceral smooth muscle cell (SMC)-dominant manner under the control of the transgelin (Tagln/SM22α) promoter via a tamoxifen-induced Cre/loxP recombination system (SM-CreER(T2)/hVEGF mice).SM-CreER(T2)/hVEGF mice received tamoxifen orally followed by microscopic examination of their pancreas 4 weeks after the hVEGF-A induction. The number of clusters of insulin-producing cells (IPCs) in islets, pancreatic ducts, and individual IPCs were counted.The number of small IPC clusters (100-215 μm(2)) in the pancreas increased significantly in SM-CreER(T2)/hVEGF mice compared with SM-CreER(T2)(Ki) mice (473 out of 1 992 counts vs. 199 out of 976 counts, p<0.05), although total IPC area and the number of pancreatic duct IPCs, in proportion to exocrine area, were similar between the 2 groups. Although most small IPC clusters observed in SM-CreER(T2)/hVEGF mice were not accompanied by α and/or δ cells, some were attached to a single or a few α cells. An STZ-induced diabetic state in SM-CreER(T2)/hVEGF mice was slightly ameliorated, with only one point of significance 12 weeks after STZ administration, compared with SM-CreER(T2)(Ki) mice.Upregulation of non-β cell-derived VEGF-A may alter the composition of pancreatic IPCs by increasing the number of small IPC clusters. These findings provide new information on the role of non-β cell-derived VEGF-A to IPC regeneration and insulin production.

Synthesis of 2α-heteroarylalkyl active vitamin d3 with therapeutic effect on enhancing bone mineral density in vivo

2α-Heteroarylethyl-1α,25-dihydroxyvitamin D3 analogues, which were designed to form a hydrogen bond between Arg274 of human vitamin D receptor (hVDR) and a nitrogen atom of the heteroaromatic ring at the 2α-position, were synthesized. Among them, 2α-[2-(tetrazol-2-yl)ethyl]-1α,25-dihydroxyvitamin D3 showed higher osteocalcin promoter transactivation activity in human osteosarcoma (HOS) cells and a greater therapeutic effect in ovariectomized (OVX) rats, osteoporosis model animals, on enhancing bone mineral density than those of active vitamin D3. X-ray cocrystallographic analysis of the hVDR-ligand complex confirms that the new hydrogen bond formation stabilized the complex.

Synthesis of 14-epi-2α-hydroxypropoxy-1α,25-dihydroxy-19-nortachysterol and its hVDR binding

Recently, we evaluated a novel skeleton in the vitamin D family, 14-epi-1α,25(OH)2-19-nortachysterol, and discovered its unique binding configuration in the human vitamin D receptor (VDR) with the C5,6- and C7,8-s-trans triene configuration. Because of its unprecedented form, this skeleton has a promising characteristic profile for clinical use, and also the synthesis of its derivatives should be versatile. Therefore, we synthesized the novel analog, 2α-hydroxypropoxy substituted 14-epi-1α,25(OH)2-19-nortachysterol, and evaluated its human VDR binding affinity. Although this substitution is one of the promising modification of vitamin D3 such as eldecalcitol (ED-71), it had negative effects on the binding affinity, and the compound showed lower affinity than 1α,25(OH)2D3 and its parent compound, 14-epi-1α,25(OH)2-19-nortachysterol. It was thought that the unprecedented binding configuration of this skeleton should not allow the terminal hydroxyl group of the 2α-substituent to construct effective hydrogen bond networks around the amino acid residues in the binding pocket. This article is part of a Special Issue entitled 'Vitamin D Workshop'.

Synthesis of novel C-2 substituted vitamin D derivatives having ringed side chains and their biological evaluation on bone

Up to the present, numerous vitamin D derivatives have been synthesized, but most of them have straight side chains, and there are few publications described about in vitro and in vivo evaluations on bone by vitamin D derivatives. In our previous paper, we reported the synthesis of various C-2 substituted vitamin D derivatives (2b-2i) with a 2,2-dimethylcyclopentanone unit in the CD-ring side chains, and that the derivatives have strong activity for enhancing bone growth. On the basis of results, this time, we report the synthesis of 2α-substituted vitamin D3 derivatives with chiral cyclopentanone (3-6 and 12-16). These derivatives were obtained by Pd-coupling reaction with A-ring precursor and CD-rings precursor. We evaluated novel derivatives in vitro assays, for affinities for VDR and transactivation assays by human osteosarcoma (HOS) cells. In this research, we demonstrated that some novel vitamin D derivatives (12-MP, 13-MP, 15-MP and 16-LP) have strong transactivation activities in spite of lower affinity for VDR than 1. In addition, we also demonstrated that these derivatives have strong activities for enhancing bone growth using OVX therapeutic rats. This article is part of a Special Issue entitled 'Vitamin D Workshop'.

TEI-A00114: a new vitamin D3 analogue that inhibits neutrophil recruitment in an acute lung injury hamster model while showing reduced hypercalcemic activity

While searching for vitamin D(3) analogues which inhibit neutrophil recruitment in the lung without elevating plasma calcium level, we found that (5Z,7E)-(1S,3R)-20(R)-[(5E)-(2S)-2-hydroxy-2-methyl-cyclopentanone-5-ylidene]methyl-9,10-secopregna-5,7,10(19)-triene-1,3-diol (TEI-A00114) had the best efficacy and calcemic action. TEI-A00114 has a vitamin D receptor affinity 2.5-fold weaker and a vitamin D binding protein affinity 330.9-fold weaker than those of 1α,25(OH)(2)D(3). The estimated effective doses for 40% inhibition (ED(40)) via peroral and intratracheal administration are 7.6 and 0.4 μg/kg, respectively. TEI-A00114 was also tested by inhaled administration, and its ED(40) was calculated as 0.2 μg/kg. The estimated 40% inhibitory concentration (IC(40)) of TEI-A00114 on interleukin (IL)-8 production induced by lipopolysaccharide and on IL-1β in human whole blood cells in vitro were 9.8 × 10(-8) or 1.8 × 10(-9)M, respectively. These levels of TEI-A00114's activities are equal to those of 1α,25(OH)(2)D(3). On the other hand, the calcemic action of TEI-A00114, which was evaluated at day 14 after sequential peroral quaque die administration, was 89-fold weaker (molar ratio) than that of 1α,25(OH)(2)D(3). These results indicate that TEI-A00114 has a dissociated profile between inhibition of neutrophil recruitment in the lung and calcemic action, suggesting its suitability over 1α,25(OH)(2)D(3) as a candidate for the treatment of acute lung injury.

Comparative study of the physiological properties of collagen, gelatin and collagen hydrolysate as cosmetic materials

The cell biological properties of collagen, gelatin and collagen hydrolysate (<15 000 Da) were studied using murine keratinocytes. Keratinocyte culture experiments demonstrated that only collagen had significant effects on cell attachment and proliferation, but the results of cells cultured on gelatin and collagen hydrolysate showed the rates of adhesion and proliferation were similar to those of cells cultured on plastic as a control. It is concluded that collagen has better physiological effects than those of gelatin and collagen hydrolysate as skin-care cosmetic materials.

C15-functionalized 16-ene-1α,25-dihydroxyvitamin D3 is a new vitamin D analog with unique biological properties

The Δ(16) structure as a vitamin D analog enhanced vitamin D receptor (VDR) binding affinity and induced significant cell differentiation, whereas its relative calcemic activity was reduced compared to 1α,25-dihydroxyvitamin D(3) (1α,25(OH)(2)D(3)). Methodologies available to introduce a double bond at C16-C17 of the D-ring on the seco-steroidal skeleton were limited; therefore, a new synthetic strategy was developed to obtain not only the Δ(16) structure, but also a new C15-functional group. Since C15-functionalization was unprecedented in vitamin D analog studies, the hybrid structure of Δ(16) and the C15-OH group at the D-ring may provide important information on the structure-activity relationship with vitamin D analogs. The synthesized 16-ene-2α-methyl-1α,15α,25-trihydroxyvitamin D(3) showed almost 3-times higher VDR binding affinity and an equipotent level of osteocalcin promoter transactivation activity in human osteosarcoma cells as compared to 1α,25(OH)(2)D(3).

The difference between 14-epi-previtamin D3 and 14-epi-19-norprevitamin D3: their synthesis and binding affinity for human VDR

The synthesis of 14-epi-1α,25(OH)(2)previtamin D(3), 14-epi-19-nor-1α,25(OH)(2)previtamin D(3), and their 2-substituted analogs is described. The vitamin D receptor (VDR) binding affinity was further evaluated and 2α-methyl substituted 14-epi-1α,25(OH)(2)previtamin D(3) had 17-fold more potent affinity than 14-epi-1α,25(OH)(2)previtamin D(3).In the comparison of these compounds, the effects of thermal equilibrium, with or without 19-carbon at the A-ring, and their CD-ring structures are discussed.

Synthesis of 2beta-substituted-14-epi-previtamin D3 and testing of its genomic activity

2beta-substituted analogs of 14-epi-previtamin D(3) were synthesized for the first time by the thermal isomerization of the corresponding 14-epi-vitamin D3 that were available using coupling reaction between the A-ring phosphine oxide derived from a chiral epoxide and CD-ring cis-hydrindanone. The VDR binding affinity and transactivation activity of osteocalcin promoter in HOS cells were evaluated, and the new analogs were found to be less active, 0.01-0.18% of VDR binding affinity compared with the natural hormone and EC50 1.0-9.1 nM for transactivation activity, than 14-epi-previtamin D3 with 0.5% (VDR) and EC50 0.46 nM, respectively.

Synthesis and biological activities of 14-epi-MART-10 and 14-epi-MART-11: implications for cancer and osteoporosis treatment

The 14-epimer of MART-10, namely 14-epi-MART-10 (14-epi-2alpha-(3-hydroxypropyl)-1alpha,25-dihydroxy-19-norvitamin D3) and its 2-epimeric analog (14-epi-MART-11) were efficiently synthesized using the Julia coupling reaction to connect between the C5 and C6 positions (steroid numbering). An A-ring precursor was prepared from (-)-quinic acid as shown in the previous MART-10 synthesis. The novel 14-epi-CD-ring coupling partner with an elongated two carbon unit as a sulfone was synthesized from 14-epi-25-hydroxy Grundmann's ketone in good yield. The subsequent coupling reaction followed by a deprotection step afforded a mixture of 14-epi-MART-10 and 14-epi-MART-11 in 40% yield. To separate 14-epi-MART-10 and 14-epi-MART-11, each primary hydroxyl group was esterified with a pivaloyl group and the resulting pivalates 2alpha and 2beta were separated by high performance liquid chromatography. After the separation, the C2-stereochemistry of each (2alpha or 2beta) was determined by 1H NMR (nuclear magnetic resonance) studies including NOE (nuclear Overhauser effect) experiments. The pivaloyl group was removed under basic conditions to obtain the target molecules of 14-epi-MART-10 and 14-epi-MART-11, respectively. The VDR (vitamin D receptor)-binding affinity, HL-60 (human promyelocytic leukemia) cell differentiation activity, antiproliferative activity in PZ-HPV-7 (immortalized normal prostate) cells and transactivation activity of the osteocalcin promoter in HOS (human osteoblast cell line) cells (serum-free conditions) were investigated. In addition, the effects on bone mineral density (BMD) and the blood and urine calcium concentrations of ovariectomized (OVX) rats were examined. 14-epi-MART-10 has much greater antiproliferative and cell differentiation activities compared to 1alpha,25-dihydroxyvitamin D3 (1alpha,25(OH)2D3).

Structure of the ligand-binding domain of rat VDR in complex with the nonsecosteroidal vitamin D3 analogue YR301

Vitamin D receptor (VDR) is a ligand-inducible hormone receptor that mediates 1alpha,25(OH)(2)D(3) action, regulating calcium and phosphate metabolism, induces potent cell differentiation activity and has immunosuppressive effects. Analogues of 1alpha,25(OH)(2)D(3) have been used clinically for some years. However, the risk of potential side effects limits the use of these substances. LG190178 is a novel nonsecosteroidal ligand for VDR. (2S)-3-[4-(3-{4-[(2R)-2-hydroxy-3,3-dimethylbutoxy]-3-methylphenyl}pentan-3-yl)-2-methylphenoxy] propane-1,2-diol (YR301) is the only one of the four evaluated stereoisomers of LG190178 to have strong activity. To understand the strong activity of YR301, the crystal structure of YR301 complexed with the rat VDR ligand-binding domain (VDR LBD) was solved at 2.0 A resolution and compared with the structure of the VDR LBD-1alpha,25(OH)(2)D(3) complex. YR301 and 1alpha,25(OH)(2)D(3) share the same position and the diethylmethyl group occupies a similar space to the C and D rings of 1alpha,25(OH)(2)D(3). YR301 has two characteristic hydroxyl groups which contribute to its potent activity. The first is 2'-OH, which forms hydrogen bonds to the NE2 atoms of both His301 and His393. The other is 2-OH, which interacts with Ser233 OG and Arg270 NH1. These two hydroxyl groups of YR301 correspond exactly to 25-OH and 1-OH, respectively, of 1alpha,25(OH)(2)D(3). The terminal hydroxyl group (3-OH) of YR301 is directly hydrogen bonded to Arg270 and also interacts indirectly with Tyr232 OH and the backbone NH of Asp144 via water molecules. Additional derivatization of the terminal hydroxyl group using the positions of the water molecules might be useful for the design of more potent compounds.

1alpha,25-Dihydroxyvitamin D(3)-26,23-lactam analogues function as vitamin D receptor antagonists in human and rodent cells

(23S,25S)-N-Benzyl-1alpha,25-dihydroxyvitamin D(3)-26,23-lactam ((23S,25S)-N-benzyl-1alpha,25-(OH)(2)D(3)-26,23-lactam, (23S,25S)-DLAM-1P) antagonizes nuclear vitamin D receptor (VDR)-mediated differentiation of human promyelocytic leukemia (HL-60) cells [Y. Kato, Y. Nakano, H. Sano, A. Tanatani, H. Kobayashi, R. Shimazawa, H. Koshino, Y. Hashimoto, K. Nagasawa, Synthesis of 1alpha,25-dihydroxy vitamin D(3)-26,23-lactams (DLAMs), a novel series of 1alpha,25-dihydroxy vitamin D(3) antagonist, Bioorg. Med. Chem. Lett. 14 (2004) 2579-2583]. To enhance its VDR antagonistic actions, we synthesized multiple analogues of 1alpha,25-(OH)(2)D(3)-26,23-lactam. Among these analogues, (23S,25S)-N-phenetyl-1alpha,25-(OH)(2)D(3)-26,23-lactam, ((23S,25S)-DLAM-2P) had the strongest VDR binding affinity, which was 3 times higher than that of (23S,25S)-DLAM-1P. The 1alpha,25-(OH)(2)D(3)-26,23-lactam analogues never induced HL-60 cell differentiation even at 10(-6)M, but (23S,25S)-DLAM-1P and (23S,25S)-DLAM-2P significantly and dose-dependently inhibited HL-60 differentiation induced by 10(-8)M 1alpha,25-dihydroxyvitamin D(3) (1alpha,25-(OH)(2)D(3)). These compounds also inhibited human and mouse cultures of osteoclast formation by marrow cells treated with 1alpha,25-(OH)(2)D(3). Moreover, the 1alpha,25-(OH)(2)D(3)-26,23-lactam analogues minimally induced 25-hydroxyvitamin D(3)-24-hydroxylase gene expression in HL-60 cells and human and mouse osteoblastic cells, but 10(-6)M (23S,25S)-DLAM-1P or (23S,25S)-DLAM-2P significantly blocked 24-hydroxylase gene expression induced by 10(-8)M 1alpha,25-(OH)(2)D(3). (23S,25S)-DLAM-2P was 5-12 times more potent as a vitamin D antagonist than (23S,25S)-DLAM-1P in HL-60 cells, human and mouse bone marrow cultures. These results demonstrate that (23S,25S)-DLAM-1P and (23S,25S)-DLAM-2P antagonize HL-60 cell differentiation and osteoclast formation by human and mouse osteoclast precursors induced by 1alpha,25-(OH)(2)D(3) through blocking VDR-mediated gene transcription. In contrast, (23S)-25-deoxy-1alpha-hydroxyvitamin D(3)-26,23-lactone, which only blocks human VDR, these vitamin D antagonists can block VDR in human cells and rodent cells.

Creative synthesis of novel vitamin D analogs for health and disease

We report new analogs of 1alpha,25-dihydroxyvitamin D(3) (1) in three categories. First, design and synthesis of ligands for a mutant vitamin D receptor (VDR)(Arg274Leu), which possess proper functional groups at both C1alpha and C2alpha positions of 1 to study the biological activity of the mutant VDR. Among our synthetic analogs, 1alpha-methyl-2alpha-(3-hydroxypropyl)-25-hydroxyvitamin D(3) (8) showed 7.3-fold greater transcriptional activity for the VDR(Arg274Leu) than that of 1. Next, we examined the antiproliferative activity of 2-substituted 19-norvitamin D(3) analogs on an immortalized normal prostate cell line, PZ-HPV-7, and we found MART 10 (14) showed the activity even at very low concentration of 10(-10) to 10(-11)M. We also synthesized 25-hydroxy-19-norvitamin D(3) (13) using Julia-type olefination to connect between the C5 and C6 positions, effectively, to test it as a prohormone type agent for antiprostate diseases. Synthesized compound 13 showed potent antiproliferative activity in PZ-HPV-7, which has high 1alpha-hydroxylase activity. Finally, we describe design and synthesis of a new TEI-9647 analog, 2alpha-(3-hydroxypropoxy)-24-propyl-25-dehydro-1alpha-hydroxyvitamin D(3)-26,23-lactone (17), which showed the strongest VDR antagonism. Its IC(50) value is 7.4pM to inhibit differentiation of HL-60 cells induced by 10nM of 1.

Further Synthetic and Biological Studies on Vitamin D Hormone Antagonists Based on C24-Alkylation and C2α-Functionalization of 25-Dehydro-1α-hydroxyvitamin D3-26,23-lactones

An efficient synthesis and the biological evaluation of 80 novel analogs of 25-dehydro-1alpha-hydroxyvitamin D3-26,23S-lactone 2 (TEI-9647) and its 23R epimer (3) in which the lactone ring was systematically functionalized by introduction of a C1 to C4 primary alkyl group at the C24 position (5 sets of 4 diastereomers), together with their C2alpha-methyl, 3-hydroxypropyl, and 3-hydroxypropoxy-substituted derivatives were described. The triene structure of the vitamin D3 was constructed using palladium-catalyzed alkenylative cyclization of the A-ring precursor enyne with the CD-ring counterpart bromoolefin having the C24-alkylated lactone moiety on the side chain. The CD-ring precursors having 23,24-cis lactones were prepared by using a chromium-mediated syn-selective allylation-lactonization process, and the 23,24-trans lactone derivatives were derived from these via inversion of the C23 stereochemistry. The biological evaluation revealed that both binding affinity for chick vitamin D hormone receptor and antagonistic activity (inhibition of vitamin D hormone induced HL-60 cell differentiation) were affected by the orientation and chain-length of the primary alkyl group on the lactone ring. Furthermore, the C2alpha-functionalization of the C24-alkylated vitamin D3 lactones dramatically enhanced their biological activities. The most potent compound to emerge, (23S,24S)-2alpha-(3-hydroxypropoxy)-24-propyl exhibited almost 1000-fold stronger antagonistic activity (IC50=7.4 pM) than 2 (IC50=6.3 nM).

[Vitamin D and cancer]

Vitamin D is a steroid hormone which regulates calcium and bone homeostasis through intestine, bone, kidney and parathyroid. It has been reported that vitamin D inhibits the cancer incidence and tumor growth. In this review, we summarize the epidemiological, animal and clinical research of vitamin D on breast, colon and prostate cancer.

Practical synthesis and evaluation of the biological activities of 1alpha,25-dihydroxyvitamin D3 antagonists, 1alpha,25-dihydroxyvitamin D3-26,23-lactams. Designed on the basis of the helix 12-folding inhibition hypothesis

A practical synthetic route to novel vitamin D antagonists of DLAM (1alpha,25-dihydroxyvitamin D(3)-26,23-lactam) was developed from vitamin D(2) via the 1,3-dipolar cycloaddition reaction as a key step. Six DLAM derivatives (24 compounds) with a variety of nitrogen substituents and stereochemistries at C23 and C25 were synthesized. Among these new derivatives, (23S,25S)-DLAM isomers bound effectively to VDRs and showed antagonistic activity in the HL-60 cell differentiation inhibition assay. The importance of the substituent on the nitrogen of DLAMs for antagonistic activity was also suggested by computational docking studies.

Molecular mechanism of the vitamin D antagonistic actions of (23S)-25-dehydro-1alpha-hydroxyvitamin D3-26,23-lactone depends on the primary structure of the carboxyl-terminal region of the vitamin d receptor

We reported that (23S)-25-dehydro-1alpha-hydroxyvitamin D(3)-26,23-lactone (TEI-9647) antagonizes vitamin D receptor (VDR)-mediated genomic actions of 1alpha,25-dihydroxyvitamin D(3) [1alpha,25(OH)(2)D(3)] in human cells but is agonistic in rodent cells. Human and rat VDR ligand-binding domains are similar, but differences in the C-terminal region are important for ligand binding and transactivation and might determine the agonistic/antagonistic effects of TEI-9647. We tested TEI-9647 on 1alpha,25(OH)(2)D(3) transactivation using SaOS-2 cells (human osteosarcoma) or ROS 24/1 cells (rat osteosarcoma) cotransfected with human or rodent VDR and a reporter. In both cell lines, TEI-9647 was antagonistic with wild-type human (h)VDR, but agonistic with overexpressed wild-type rat (r)VDR. VDR chimeras substituting the hVDR C-terminal region (activation function 2 domain) with corresponding rVDR residues diminished antagonism and increased agonism of TEI-9647. However, substitution of 25 C-terminal rVDR residues with corresponding hVDR residues diminished agonism and increased antagonism of TEI-9647. hVDR mutants (C403S, C410N) demonstrated that Cys403 and/or 410 was necessary for TEI-9647 antagonism of 1alpha,25(OH)(2)D(3) transactivation. These results suggest that species specificity of VDR, especially in the C-terminal region, determines the agonistic/antagonistic effects of TEI-9647 that determine, in part, VDR interactions with coactivators and emphasize the critical interaction between TEI-9647 and the two C-terminal hVDR Cys residues to mediate the antagonistic effect of TEI-9647.

Synthesis and structure-activity relationships of TEI-9647 derivatives as Vitamin D3 antagonists

The Vitamin D(3) lactone analogues, (23S)- and (23R)-25-dehydro-1alpha-hydroxyvitamin D(3)-26,23-lactone (TEI-9647 and TEI-9648) are antagonists of the 1alpha,25-dihydroxyvitamin D(3) (1alpha,25-(OH)(2)D(3)) nuclear receptor (VDR)-mediated differentiation of human leukemia (HL-60) cells. In order to clarify the structure-Vitamin D antagonistic activity relationship, we paid attention to the unique lactone moiety of TEI-9647 and TEI-9648: alpha-exo-methylene-gamma-lactone structure. We synthesized the exo-methylene-modified analogues (methylene saturated, endo-methylene, methylene-deleted, methyl-substituted, dimethyl-substituted, methylene-replaced with dimethyl and cyclopropane) and oxygen-modified analogues (oxygen atom replaced with nitrogen and carbon atom) by convergent method using palladium-catalyzed coupling reaction or direct modification of VD(3) skeleton. The antagonistic activity in HL-60 cell differentiation evaluating system of these analogues revealed that any exo-methylene-modified analogues and nitrogen analogue did not have the antagonistic activity, on the other hand carbon analogue did show. The results suggest that "alpha-exo-methylene carbonyl" structure of VD(3) side-chain is crucial for antagonistic activity. The structure is integral building block of many natural products which have interesting biological and it is thought that Michael-type addition of alpha-exo-methylene carbonyl structure with protein nucleophiles such as cysteine would play an important role for the activities. According to this theory, Michael-type reaction of TEI-9647 and TEI-9648 with cysteine residue in protein related to VDR/VDRE-mediated genomic actions such as VDR would be essential step of the antagonistic action.

Vitamin D antagonist, TEI-9647, inhibits osteoclast formation induced by 1alpha,25-dihydroxyvitamin D3 from pagetic bone marrow cells

(23S)-25-Dehydro-1alpha-hydroxyvitamin D(3)-26,23-lactone (TEI-9647) functions an antagonist of the 1alpha,25-dihydroxyvitamin D(3) (1alpha,25-(OH)(2)D(3)) nuclear receptor (VDR)-mediated differentiation of human leukemia (HL-60) cells [J. Biol. Chem. 274 (1999) 16392]. We examined the effect of vitamin D antagonist, TEI-9647, on osteoclast formation induced by 1alpha,25-(OH)(2)D(3) from bone marrow cells of patients with Paget's disease. TEI-9647 itself never induced osteoclast formation even at 10(-6)M, but dose-dependently (10(-10) to 10(-6)M) inhibited osteoclast formation induced by physiologic concentrations of 1alpha,25-(OH)(2)D(3) (41 pg/ml, 10(-10)M) from bone marrow cells of patients with Paget's disease. At the same time, 10(-8)M of TEI-9647 alone did not cause 1alpha,25-(OH)(2)D(3) dependent gene expression, but almost completely suppressed TAF(II)-17, a potential coactivator of VDR and 25-hydroxyvitamin D(3)-24-hydroxylase (25-OH-D(3)-24-hydroxylase) gene expression induced by 10(-10)M 1alpha,25-(OH)(2)D(3) in bone marrow cells of patients with Paget's disease. Moreover, TEI-9647 dose-dependently inhibited bone resorption induced by 10(-9)M 1alpha,25-(OH)(2)D(3) by osteoclasts produced by RANKL and M-CSF treatment of measles virus nucleocapsid gene transduced bone marrow cells. These results suggest that TEI-9647 acts directly on osteoclast precursors and osteoclasts, and that TEI-9647 may be a novel agent to suppress the excessive bone resorption and osteoclast formation in patients with Paget's disease.

Dramatic Enhancement of Antagonistic Activity on Vitamin D Receptor: A Double Functionalization of 1α-Hydroxyvitamin D3 26,23-Lactones

The synthesis of novel vitamin D receptor antagonists, 24-methyl-1alpha-hydroxyvitamin D(3) 26,23-lactones, is reported. We found that the biological activities of the vitamin D(3) lactones were affected by the structure of the lactone part. Furthermore, introduction of a 2alpha-methyl group into the 24-methylvitamin D(3) lactones dramatically enhanced their anti-vitamin D activity. [reaction: see text]

Remarkable effect of 2α-modification on the VDR antagonistic activity of 1α-hydroxyvitamin D3-26,23-lactones

Novel 2[small alpha]-methyl-, 2[small alpha]-(3-hydroxypropyl)- and 2[small alpha]-(3-hydroxypropoxy)-substituted 25-dehydro-1[small alpha]-hydroxyvitamin D-26,23-lactone derivatives were efficiently synthesized Reformatsky type allylation and palladium-catalyzed alkenylative cyclization processes, and their biological activities were evaluated. Introducing functional groups into the 2[small alpha]-position of the vitamin D-26,23-lactones resulted in remarkable enhancement of their antagonistic activity on vitamin D receptor (VDR).

Aberrant brain activation following motor skill learning in schizophrenic patients as shown by functional magnetic resonance imaging

BACKGROUND

Motor skill learning may be impaired in schizophrenia. While functional brain imaging studies have shown reduced activation during motor task performance in schizophrenic patients, brain activity changes with motor skill learning in these patients have not been studied by functional imaging.

METHODS

A sequential complex motor task involving the right hand was performed by nine medicated schizophrenic patients and 10 age-matched healthy controls. Functional magnetic resonance images were obtained using a gradient echo, echoplanar imaging (EPI) pulse sequence before and after 1 week of training in performing the task.

RESULTS

Bilaterally, patients showed significantly less blood oxygenation level-dependent (BOLD) signal response in the premotor area (PMA) before beginning motor training than controls. BOLD signal response increased in the left PMA of schizophrenic patients after 1 week of motor training; in contrast, the signal decreased in the left PMA of control subjects. Training effects concerning the number of finger movement sequences achieved did not differ between groups. Daily neuroleptic dose did not significantly affect changes with training in BOLD signal response in the PMA.

CONCLUSIONS

These preliminary results suggest that schizophrenic patients have dysfunction of neural networks in areas including the PMA that are involved in executing a complex motor task. In terms of brain activity, motor learning may be less efficient or slower in the patients than in healthy subjects.

Directed coherence of EEG on ICSS rats with methamphetamine-induced hyperactivity and stereotyped behavior

Methamphetamine (MAP) can reinforce intracranial self-stimulation (ICSS) in rats, that is, reward-seeking behavior. However, the ICSS can be inhibited by the stereotyped behavior induced by MAP. This study was designed to observe the mutual information flow between prefrontal cortex (PFC) and ventral tegmental area (VTA) using directed coherence (DC) analysis during the hyperactivity and stereotyped behavior induced by administration of MAP (a derivative of amphetamine). The DC from PFC to VTA increased at 5-7 Hz in the hyperactivity as compared to the stereotypy. In contrast, enhanced information flow from VTA to PFC was observed in the stereotypy as compared to the hyperactivity. We found a reciprocal information flow between PFC and VTA corresponding to the hyperactivity and stereotyped behavior that was induced by administration of MAP.

Reciprocal information flow between prefrontal cortex and ventral tegmental area in an animal model of schizophrenia

The medial prefrontal cortex (PFC) is anatomically and functionally connected with the ventral tegmental area (VTA), the neuronal source of mesocorticolimbic system that is pathophysiologically related to schizophrenia-like symptoms. Methamphetamine (MAP) was applied to examine the functional relationship between PFC and VTA in an animal model of schizophrenia. Hyperactivity and stereotyped behavior were observed accompanied by a distinctive direction of information flow. In hyperactivity, information flow in the direction from PFC to VTA was dominant. Contrarily, dominant information flow from VTA to PFC was found in stereotyped behavior. These results indicate that dysfunctional interaction between PFC and VTA is the neuronal basis of MAP-induced schizophrenia-like psychosis. The information flow and its direction can be useful tool to explain the neurogenesis of these abnormal behaviors.

An efficient method for production of uridine 5'-diphospho-N-acetylglucosamine

Uridine 5'-diphospho-N-acetylglucosamine (UDP-GlcNAc) has been synthesized by a yeast-based method from 5'-UMP and glucosamine, in which yeast cells catalyze the conversion of 5'-UMP to 5'-UTP and provide enzymes involved in UDP-GlcNAc synthesis using 5'-UTP and glucosamine as substrates. However, this conventional method is not suitable for practical production of UDP-GlcNAc because of the low yield of the product. We found that the yqgR gene product of Bacillus subtilis, which has been identified as a glucokinase, can catalyze the phosphorylation of N-acetylglucosamine (GlcNAc) to give GlcNAc-6-phosphate, an intermediate of UDP-GlcNAc biosynthesis. The addition of the yqgR gene product to the yeast-based reaction system enabled us to synthesize UDP-GlcNAc using GlcNAc in place of glucosamine. The addition of two enzymes, GlcNAc-phosphate mutase and UDP-GlcNAc pyrophosphorylase, increased the yield of UDP-GlcNAc. Using this novel method, UDP-GlcNAc was produced at an amount of 78 mM from 100 mM 5'-UMP and 100 mM GlcNAc.

Organization of extracellular matrix components during differentiation of adipocytes in long-term culture

Scanning electron microscopy (SEM) observation showed that fully differentiated spherical adipocytes were embraced by a network of collagens and fibroblastic preadipocytes. The properties of both the collagen networks and the preadipocytes allow the adipocytes to be interconnected, forming a fat-cell cluster, which can anchor to the bottom of a culture dish. In this network structure, collagen fibrils and fibrillar bundles were closely arranged and stratified. We found that immunostained collagens appeared to form extracellular network structures, which can be observed by SEM. The extracellular network of fibronectin was the first to develop among the extracellular matrix (ECM) components, though it became degraded with the progress of adipocyte differentiation. The type I collagen network was the last to develop and remained well organized through the late stage of adipocyte differentiation. The extracellular networks of type III, V, and VI collagen developed by the mid-stage and remained in the late stage of adipocyte differentiation. The network structures of type IV collagen and laminin became degraded during the differentiation process and localized at the surface of spherical cells. In addition to these basement membrane components, types III, V, and VI collagens also showed pericellular spherical staining patterns. These results demonstrated that the constitution and distribution of the ECM are altered during adipocyte differentiation, suggesting that the organization of each ECM component into a suitable structure is a requirement for the differentiation and maintenance of unilocular adipocytes.

Organization of extracellular matrix components during differentiation of adipocytes in long-term culture

Scanning electron microscopy (SEM) observation showed that fully differentiated spherical adipocytes were embraced by a network of collagens and fibroblastic preadipocytes. The properties of both the collagen networks and the preadipocytes allow the adipocytes to be interconnected, forming a fat-cell cluster, which can anchor to the bottom of a culture dish. In this network structure, collagen fibrils and fibrillar bundles were closely arranged and stratified. We found that immunostained collagens appeared to form extracellular network structures, which can be observed by SEM. The extracellular network of fibronectin was the first to develop among the extracellular matrix (ECM) components, though it became degraded with the progress of adipocyte differentiation. The type I collagen network was the last to develop and remained well organized through the late stage of adipocyte differentiation. The extracellular networks of type III, V, and VI collagen developed by the mid-stage and remained in the late stage of adipocyte differentiation. The network structures of type IV collagen and laminin became degraded during the differentiation process and localized at the surface of spherical cells. In addition to these basement membrane components, types III, V, and VI collagens also showed pericellular spherical staining patterns. These results demonstrated that the constitution and distribution of the ECM are altered during adipocyte differentiation, suggesting that the organization of each ECM component into a suitable structure is a requirement for the differentiation and maintenance of unilocular adipocytes.

Lateralized memory deficits on the Wada test correlate with the side of lobectomy only for patients with unilateral medial temporal lobe epilepsy

The aim of this study was to determine whether the predictive value of the intracarotid amobarbital test (IAT) for the side to be resected is applicable only to medial temporal lobe epilepsy and to investigate whether there are different patterns of memory performances on the IAT between patients with unilateral mesial temporal sclerosis (UMT group) and those without (non-UMT group). We studied 30 patients in the UMT group and 10 in the non-UMT group, who underwent pre-surgical evaluation for intractable temporal lobe epilepsy. Memory performances on the IAT was defined as the percentage of memory items presented during unilateral hemispheric anesthesia that was recognized after recovery. More than a 20% decline of the memory performance on the IAT compared with the memory performance on the pre-test was regarded as a memory deficit. Age at onset of epilepsy was significantly younger in the UMT than in the non-UMT group. Surgical outcome was significantly better in the UMT than in the non-UMT group. The lateralizing value of unilateral memory deficits on the IAT was statistically confirmed. There was a significant association between falsely lateralizing memory performances and the non-UMT group. Excluding the exceptional cases with right-sided language dominance in spite of right-sided lesions, the high incidence of the unilateral right-sided memory deficits in the non-UMT group was statistically significant. This study suggested that the excellent lateralizing value of the memory performances on the IAT is limited to patients with mesial temporal lobe epilepsy. IAT memory performances in patients without such lesions can be misleading, even if lateralized, because their memory status presumably reflects a natural lateralization of the memory organization which is independent of the epileptogenic focus.

Emotional and behavioral correlates of the anterior cingulate cortex during associative learning in rats

Neuronal activity was recorded from the anterior cingulate cortex of behaving rats during discrimination and learning of conditioned stimuli associated with or without reinforcements. The rats were trained to lick a protruding spout just after a conditioned stimulus to obtain reward (intracranial self-stimulation or sucrose solution) or to avoid aversion. The conditioned stimuli included both elemental (auditory or visual stimuli) and configural (simultaneous presentation of auditory and visual stimuli predicting reward outcome opposite to that predicted by each stimulus presented alone) stimuli. Of the 62 anterior cingulate neurons responding during the task, 38 and four responded differentially and non-differentially to the conditioned stimuli (conditioned stimulus-related neurons), respectively. Of the 38 differential conditioned stimulus-related neurons, 33 displayed excitatory (n = 10) and inhibitory (n = 23) responses selectively to the conditioned stimuli predicting reward. These excitatory and inhibitory differential conditioned stimulus-related neurons were located mainly in the cingulate cortex areas 1 and 3 of the rostral and ventral parts of the anterior cingulate cortex, respectively. The remaining 20 neurons responded mainly during intracranial self-stimulation and/or ingestion of sucrose (ingestion/intracranial self-stimulation-related neurons). Increase in activity of the ingestion/intracranial self-stimulation-related neurons was correlated to the first lick to obtain rewards during the task, suggesting that the activity reflected some aspects of motor functions for learned instrumental behaviors. These ingestion/intracranial self-stimulation-related neurons were located sparsely in cingulate cortex area 1 of the rostral part of the anterior cingulate cortex and densely in frontal area 2 of the caudal and dorsal parts of the anterior cingulate cortex. Analysis by the multidimensional scaling of responses of 38 differential conditioned stimulus-related neurons indicated that the anterior cingulate cortex categorized the conditioned stimuli into three groups based on reward contingency, regardless of the physical characteristics of the stimuli, in a two-dimensional space; the three conditioned (two elemental and one configural) stimuli predicting sucrose solution, the three conditioned (two elemental and one configural) stimuli predicting no reward, and the lone conditioned stimulus predicting intracranial self-stimulation. The results suggest that the anterior cingulate cortex is organized topographically; stimulus attributes predicting reward or no reward are represented in the rostral and ventral parts of the anterior cingulate cortex, while the caudal and dorsal parts of the anterior cingulate cortex are related to execution of learned instrumental behaviors. These results are in line with recent neuropsychological studies suggesting that the rostral part of the anterior cingulate cortex plays a crucial role in socio-emotional behaviors by assigning a positive or negative value to future outcomes.

Effect of intraduodenal lipid on parabrachial gustatory coding in awake rats

Intestinal fat differentially suppresses sham feeding of liquid diets and preferred gustatory stimuli. Although the behavioral effect is robust, no electrophysiological evidence exists to account for its neural basis. Therefore, we investigated the effect of intestinal fat on gustatory coding in the pontine parabrachial nuclei (PBN) by recording from single neurons in awake rats before, during, and after intraduodenal infusions of lipid (Intralipid; 10 ml, 5 kcal). Intraduodenal lipid did not alter the response profiles of PBN taste neurons. It did, however, produce an overall decrease in response magnitude (-16.25%; n = 43), with the largest reduction to sucrose (-30%; n = 43). The most pronounced suppression occurred in sucrose-best neurons in response to sucrose (-55%; n = 19), and this effect was largest for the sucrose-specific cells (-77%; n = 3). After lipid infusions, nonspecific neurons in both the sucrose-best and NaCl-best categories also responded less to their best stimulus (sucrose, -46%; n = 16; NaCl, -35%; n = 13). In contrast, no significant changes were found in NaCl-specific cells in response to NaCl. All effects appeared with short latency ( approximately 5 min) and were reversible within the time frame of a meal. In controls, duodenal infusions of saline did not cause any changes in taste responsiveness. These results suggest that intestinal fat has specific effects on taste coding in the PBN that may contribute to the intake suppression of palatable food observed in behavioral studies. The similar, short latency of both the behavioral and neural effects supports the hypothesis of a preabsorptive site of action.