This letter describes the discovery and SAR optimization of tetrazoyl tetrahydroquinoline derivatives as potent CETP inhibitors. Compound 6m exhibited robust HDL-c increase in hCETP/hApoA1 double ...transgenic model and favorable pharmacokinetic properties.
2-Methylalanyl-N-{1-(1R)-1-(4-fluorophenyl)-1-methyl-2-oxo-2-pyrrolidin-1-ylethyl-1H-imidazol-4-yl}-5-phenyl-D-norvalinamide (LY654322) was rapidly cleared in rats and dogs by renal excretion of ...parent and metabolism (oxidative and hydrolytic). Among the metabolites identified in the urine of rats and dogs was M25, which was structurally unusual. Indeed, the characterization of M25 and investigation into its disposition relied on the convergence of diverse analytical methodologies. M25 eluted after the parent on reverse-phase chromatography with an MH(+) at m/z 598 (parent + 35 Da). Given its increased lipophilicity and its mass difference compared with the parent, it was evident that M25 was not a phase 2 conjugate. Subsequent liquid chromatography with multiple-stage tandem mass spectrometry and accurate mass experiments identified the structure of M25 as having two replicates of the 1-(4-fluorophenyl)-1-methyl-2-oxo-2-pyrrolidinyl substructure flanking a central aromatic core of composition C(7)H(3)N(5) that was refractory to fragmentation. Compared with the UV spectrum of the parent (λ(max) = 213 nm), M25 displayed a bathochromic shift (λ(max) = 311 nm), which substantiated extensive conjugation within the central core. Subsequent NMR analysis of M25 isolated from dog urine coupled with molecular modeling revealed the structure to be consistent with a diimidazopyridine core with two symmetrically substituted 1-(4-fluorophenyl)-1-methyl-2-oxo-2-pyrrolidinyl moieties. Using a structural analog with a chromophore similar to M25, LC-UV was used to quantitate M25 and determine its urinary disposition. The formation of M25 appears consistent with hydrolysis of LY654322 to an aminoimidazole, dimerization of the latter with the loss of NH(3), C-formylation, and subsequent ring closure and aromatization with loss of H(2)O.
La main humaine est considérée comme unique au travers certaines spécificités fonctionnelles comme l’individualisation des doigts et la capacité de saisir avec puissance un outil entre le pouce et le ...côté latéral de l'index. Cependant, les primates non-humains présentent de grandes capacités de manipulations. Ainsi, peut-on réellement affirmer que ces caractéristiques fonctionnelles humaines ne sont pas partagées par d'autres primates ? L'étude préliminaire menée ici a pour objectif d'analyser les stratégies de manipulation chez des humains, adultes (N = 10 hommes, âge = 28 ± 5,92 ans) comme enfants (N = 10 garçons, âge = 5,3 ± 0,48) et des bonobos ("Pan paniscus") captifs (N = 6 dont 4 femelles et 2 mâles, âge = 20,33 ± 5,31) au cours d’une même tâche nécessitant la manipulation d'un outil. Cette nouvelle tâche consiste à récupérer une noix placée dans un labyrinthe en bois et ceci à travers un grillage. Les deux espèces disposaient d'un choix varié de branches (divers tailles et diamètres). Trois sessions par individu, une session correspondant à 1 noix récupérée, ont été menées chez les bonobos comme les humains. Différents paramètres ont été quantifiés comme le type de saisie (uni-manuelle versus bi-manuelle), de postures manuelles (e.g. puissance, précision) et la performance (basée sur les nombres de mouvements et d'obstacles touchés). Les résultats montrent des différences inter et intra-spécifiques et un effet de l'âge chez les humains pour certains paramètres. Tout d'abord, les bonobos ont utilisé un seul outil avec une seule main alors que les humains (adultes et enfants) ont employé en majorité des stratégies bi-manuelles (65 %) et les adultes se sont parfois servis de deux outils (30 %). Concernant les saisies uni-manuelles, les bonobos ont utilisé 32 formes de postures manuelles contre 26 pour les humains adultes et 125 pour les enfants. Au cours des saisies bi-manuelles, 4 fois plus de postures ont été quantifiées. Par ailleurs, les enfants ont davantage utilisé des saisies de puissance que les adultes qui ont principalement employé une saisie de précision à 3 doigts (e.g. tenue du stylo) pendant que les bonobos ont présenté des préférences différenciées au niveau individuel. Pour finir, les adultes humains se sont montrés plus performants que les bonobos, eux-mêmes plus performants que les enfants. L'utilisation des deux mains chez les humains pourrait s'expliquer par une saisie plus stable et puissante de l'outil pendant que l'utilisation de deux outils chez les adultes, plus complexe sur le plan de la coordination, pourrait apporter à certains individus une optimisation du trajet de la noix par dissociation des actions de la main droite versus de la main gauche (pousser vs contrôler). La plus grande variabilité des types de saisies chez les enfants pourrait s'expliquer par le manque d'expérience et d'apprentissage dans les stratégies de manipulation. Les bonobos présentent quant à eux des spécificités individuelles pouvant traduire la spécialisation de leurs stratégies de manipulations. L'ensemble des résultats montre qu’il est nécessaire d'approfondir les manipulations d'objets afin de mieux comprendre les spécificités de chaque espèce, et pas seulement humaines, et les causes des convergences parfois partagées. Seule une approche détaillée et comparative (inter et intra-spécifique) nous permettra de discuter sous un nouvel angle l'émergence des éventuelles spécificités humaines.
Lipoprotein(a) (Lp(a)), an independent, causal cardiovascular risk factor, is a lipoprotein particle that is formed by the interaction of a low-density lipoprotein (LDL) particle and ...apolipoprotein(a) (apo(a))
. Apo(a) first binds to lysine residues of apolipoprotein B-100 (apoB-100) on LDL through the Kringle IV (K
) 7 and 8 domains, before a disulfide bond forms between apo(a) and apoB-100 to create Lp(a) (refs.
). Here we show that the first step of Lp(a) formation can be inhibited through small-molecule interactions with apo(a) K
7-8. We identify compounds that bind to apo(a) K
7-8, and, through chemical optimization and further application of multivalency, we create compounds with subnanomolar potency that inhibit the formation of Lp(a). Oral doses of prototype compounds and a potent, multivalent disruptor, LY3473329 (muvalaplin), reduced the levels of Lp(a) in transgenic mice and in cynomolgus monkeys. Although multivalent molecules bind to the Kringle domains of rat plasminogen and reduce plasmin activity, species-selective differences in plasminogen sequences suggest that inhibitor molecules will reduce the levels of Lp(a), but not those of plasminogen, in humans. These data support the clinical development of LY3473329-which is already in phase 2 studies-as a potent and specific orally administered agent for reducing the levels of Lp(a).
It is postulated that the hepatotoxicity of valproic acid (VPA) results from the mitochondrial beta-oxidation of its cytochrome P450 metabolite, 2-propyl-4-pentenoic acid (4-ene VPA), to ...2-propyl-(E)-2,4-pentadienoic acid ((E)-2,4-diene VPA) which, in the CoA thioester form, either depletes GSH or produces a putative inhibitor of beta-oxidation enzymes. In order to test this hypothesis, 2-fluoro-2-propyl-4-pentenoic acid (alpha-fluoro-4-ene VPA) which was expected to be inert to beta-oxidative metabolism was synthesized and its effect on rat liver studied in comparison with that of 4-ene VPA. Similarly, the known hepatotoxicant 4-pentenoic acid (4-PA) and 2,2-difluoro-4-pentenoic acid (F2-4-PA) were compared. Male Sprague-Dawley rats (150-180 g, 4 rats per group) were dosed ip with 4-ene VPA (0.7 mmol/kg per day), 4-PA (1.0 mmol/kg per day), or equivalent amounts of their alpha-fluorinated analogues for 5 days. Both 4-ene VPA and 4-PA induced severe hepatic microvesicular steatosis ( > 85% affected hepatocytes), and 4-ene VPA produced mitochondrial alterations. By contrast, alpha-fluoro-4-ene VPA and F2-4-PA were not observed to cause morphological changes in the liver. The major metabolite of 4-ene VPA in the rat urine and serum was the beta-oxidation product (E)-2,4-diene VPA. The N-acetylcysteine (NAC) conjugate of (E)-2,4-diene VPA was also found in the urine. Neither (E)-2,4-diene VPA nor the NAC conjugate could be detected in the rats administered alpha-fluoro-4-ene VPA. In a second set of rats (3 rats per group), total liver GSH levels were determined to be depleted to 56% and 72% of control following doses of 4-ene VPA (1.4 mmol/kg) and equivalent alpha-fluoro-4-ene VPA, respectively. Mitochondrial GSH remained unchanged in the alpha-fluoro-4-ene VPA treated group but was reduced to 68% of control in the rats administered 4-ene VPA. These results strongly support the theory that hepatotoxicity of 4-ene VPA, and possibly VPA itself, is mediated largely through beta-oxidation of 4-ene VPA to reactive intermediates that are capable of depleting mitochondrial GSH.
The synthesis and biological evaluation of a series of benzimidazolone beta(3) adrenergic receptor agonists are described. A trend toward the reduction of rat atrial tachycardia upon increasing ...steric bulk at the 3-position of the benzimidazolone moiety was observed.
The microsomal metabolism of 7-ethoxycoumarin (7-EC) was investigated using liquid chromatography (LC)-NMR and liquid chromatography-mass spectrometry (LC-MS) to characterize the coupling of ...oxidative-conjugative metabolism events. Within microsomes, cytochromes P450 (P450s) and UDP-glucuronosyltransferases (UGTs) are spatially disparate, each having surface and luminal localization, respectively. To optimize cofactor and substrate transit to UGT without compromising P450 activity, the pore-forming peptide alamethicin was used for microsomal perforation. Aqueous extracts of microsomal incubations containing NADPH and UDP-glucuronic acid were injected for LC-NMR and LC-MS analysis. The analytical complementarity of LC-NMR and LC-MS permitted the identification of four metabolites (M1 to M4). The metabolites M1 and M2 are novel microsomal metabolites for 7-EC, consistent with 3-hydroxylation and subsequent glucuronidation, respectively. Metabolites M3 and M4 were 7-hydroxycoumarin (7-HC) and 7-HC glucuronide, respectively. Viewed collectively, these results illustrate the utility of alamethicin in the examination of coupled oxidative-conjugative metabolism and the synergy of LC-NMR and LC-MS in metabolite identification.
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