Identification of hepta-histidine as a candidate drug for Huntington's disease by in silico-in vitro- in vivo-integrated screens of chemical libraries.

We identified drug seeds for treating Huntington's disease (HD) by combining in vitro single molecule fluorescence spectroscopy, in silico molecular docking simulations, and in vivo fly and mouse HD models to screen for inhibitors of abnormal interactions between mutant Htt and physiological Ku70, an essential DNA damage repair protein in neurons whose function is known to be impaired by mutant Htt. From 19,468 and 3,010,321 chemicals in actual and virtual libraries, fifty-six chemicals were selected from combined in vitro-in silico screens; six of these were further confirmed to have an in vivo effect on lifespan in a fly HD model, and two chemicals exerted an in vivo effect on the lifespan, body weight and motor function in a mouse HD model. Two oligopeptides, hepta-histidine (7H) and Angiotensin III, rescued the morphological abnormalities of primary neurons differentiated from iPS cells of human HD patients. For these selected drug seeds, we proposed a possible common structure. Unexpectedly, the selected chemicals enhanced rather than inhibited Htt aggregation, as indicated by dynamic light scattering analysis. Taken together, these integrated screens revealed a new pathway for the molecular targeted therapy of HD

25<i>S</i>‑Adamantyl-23-yne-26,27-dinor-1α,25-dihydroxyvitamin D₃: Synthesis, Tissue Selective Biological Activities, and X‑ray Crystal Structural Analysis of Its Vitamin D Receptor Complex

Both 25<i>R</i>- and 25<i>S</i>-25-adamantyl-23-yne-26,27-dinor-1α,25-dihydroxy­vitamin D₃ (<b>4a</b> and <b>4b</b>) were stereoselectively synthesized by a Pd(0)-catalyzed ring closure and Suzuki–Miyaura coupling between enol-triflate <b>7</b> and alkenyl-boronic ester <b>8</b>. The 25<i>S</i> isomer (<b>4b</b>) showed high vitamin D receptor (VDR) affinity (50% of that of the natural hormone 1α,25-dihydroxy­vitamin D₃, <b>1</b>) and transactivation potency (kidney HEK293, 90%). In endogenous gene expression, it showed high cell-type selectivity for kidney cells (HEK293, CYP24A1 160% of <b>1</b>), bone cells (MG63, osteocalcin 64%), and monocytes (U937, CAMP 96%) over intestine (SW480, CYP24A1 8%) and skin (HaCaT, CYP24A1 7%) cells. The X-ray crystal structural analysis of <b>4b</b> in complex with rat VDR-ligand binding domain (LBD) showed the highest Cα positional shift from the <b>1/</b>VDR-LBD complex at helix 11. Helix 11 of the <b>4b</b> and <b>1</b> VDR-LBD complexes also showed significant differences in surface properties. These results suggest that <b>4b</b> should be examined further as another candidate for a mild preventive osteoporosis agent

25<i>S</i>‑Adamantyl-23-yne-26,27-dinor-1α,25-dihydroxyvitamin D₃: Synthesis, Tissue Selective Biological Activities, and X‑ray Crystal Structural Analysis of Its Vitamin D Receptor Complex

Both 25<i>R</i>- and 25<i>S</i>-25-adamantyl-23-yne-26,27-dinor-1α,25-dihydroxy­vitamin D₃ (<b>4a</b> and <b>4b</b>) were stereoselectively synthesized by a Pd(0)-catalyzed ring closure and Suzuki–Miyaura coupling between enol-triflate <b>7</b> and alkenyl-boronic ester <b>8</b>. The 25<i>S</i> isomer (<b>4b</b>) showed high vitamin D receptor (VDR) affinity (50% of that of the natural hormone 1α,25-dihydroxy­vitamin D₃, <b>1</b>) and transactivation potency (kidney HEK293, 90%). In endogenous gene expression, it showed high cell-type selectivity for kidney cells (HEK293, CYP24A1 160% of <b>1</b>), bone cells (MG63, osteocalcin 64%), and monocytes (U937, CAMP 96%) over intestine (SW480, CYP24A1 8%) and skin (HaCaT, CYP24A1 7%) cells. The X-ray crystal structural analysis of <b>4b</b> in complex with rat VDR-ligand binding domain (LBD) showed the highest Cα positional shift from the <b>1/</b>VDR-LBD complex at helix 11. Helix 11 of the <b>4b</b> and <b>1</b> VDR-LBD complexes also showed significant differences in surface properties. These results suggest that <b>4b</b> should be examined further as another candidate for a mild preventive osteoporosis agent

Combination of Triple Bond and Adamantane Ring on the Vitamin D Side Chain Produced Partial Agonists for Vitamin D Receptor

Vitamin D receptor (VDR) ligands are therapeutic agents that are used for the treatment of psoriasis, osteoporosis, and secondary hyperparathyroidism and have immense potential as therapeutic agents for autoimmune diseases, cancers, and cardiovascular diseases. However, the major side effect of VDR ligands, the development of hypercalcemia, limits their expanded use. To develop tissue-selective VDR modulators, we have designed vitamin D analogues with an adamantane ring at the side chain terminal, which would interfere with helix 12, the activation function 2, and modulate the VDR potency. Here we report 25- or 26-adamantyl-23,23,24,24-tetradehydro-19-norvitamin D derivatives (ADTK1–4, <b>4b</b>,<b>a</b> and <b>5a</b>,<b>b</b>). These compounds showed high VDR affinities (90% at maximum), partial agonistic activities (EC₅₀ 10^–9–10^–8 M with 40–80% efficacy) in transactivation, and tissue-selective activity in target gene expressions. We investigate the structure–activity relationships of these compounds on the basis of their X-ray crystal structures

Synthesis, Biological Activities, and X‑ray Crystal Structural Analysis of 25-Hydroxy-25(or 26)-adamantyl-17-[20(22),23-diynyl]-21-norvitamin D Compounds

Novel 19-norvitamin D analogues (ADYW1–4, <b>5a</b>–<b>d</b>) in which an adamantyl diyne side chain is attached directly to the 17-position of the D ring are designed and stereoselectively synthesized. The adamantane ring of these analogues was expected to interfere with helix 12 (H12, activation function 2) of the vitamin D receptor (VDR) to modulate its activities. The analogue <b>5b</b> binds to the VDR (7% of the natural hormone) and shows significant partial agonistic activity in transactivation assay. Compound <b>5b</b> showed considerable selectivity in VDR target genes expressions in vitro, it was taken up by target cells 2–3 times more readily, and its lifetime was three times longer than the natural hormone. The X-ray crystal structure of <b>5b</b> in complex with VDR reveals that the ligand binds similarly to the natural hormone, but the diyne moiety is slightly bent (angles around the diyne 5° to 8°) with respect to the original diyne vitamin D compound <b>6</b> in VDR (<1°) due to steric hindrance with helix 12

Combination of Triple Bond and Adamantane Ring on the Vitamin D Side Chain Produced Partial Agonists for Vitamin D Receptor

Vitamin D receptor (VDR) ligands are therapeutic agents that are used for the treatment of psoriasis, osteoporosis, and secondary hyperparathyroidism and have immense potential as therapeutic agents for autoimmune diseases, cancers, and cardiovascular diseases. However, the major side effect of VDR ligands, the development of hypercalcemia, limits their expanded use. To develop tissue-selective VDR modulators, we have designed vitamin D analogues with an adamantane ring at the side chain terminal, which would interfere with helix 12, the activation function 2, and modulate the VDR potency. Here we report 25- or 26-adamantyl-23,23,24,24-tetradehydro-19-norvitamin D derivatives (ADTK1–4, <b>4b</b>,<b>a</b> and <b>5a</b>,<b>b</b>). These compounds showed high VDR affinities (90% at maximum), partial agonistic activities (EC₅₀ 10^–9–10^–8 M with 40–80% efficacy) in transactivation, and tissue-selective activity in target gene expressions. We investigate the structure–activity relationships of these compounds on the basis of their X-ray crystal structures