Publications by authors named "Stephen J Orena"

Background & Aims: Hyperhomocysteinemia is often associated with liver and metabolic diseases. We studied nuclear receptors that mediate oscillatory control of homocysteine homeostasis in mice.

Methods: We studied mice with disruptions in Nr0b2 (called small heterodimer partner [SHP]-null mice), betaine-homocysteine S-methyltransferase (Bhmt), or both genes (BHMT-null/SHP-null mice), along with mice with wild-type copies of these genes (controls).

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TNFalpha plays key roles in the regulation of inflammation, cell death, and proliferation and its signaling cascade cross-talks with the insulin signaling cascade. PKCdelta, a novel PKC isoform, is known to participate in proximal TNFalpha signaling events. However, it has remained unclear whether PKCdelta plays a role in distal TNFalpha signaling events.

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A series of 4-substituted proline amides was synthesized and evaluated as inhibitors of dipeptidyl pepdidase IV for the treatment of type 2 diabetes. (3,3-Difluoro-pyrrolidin-1-yl)-[(2S,4S)-(4-(4-pyrimidin-2-yl-piperazin-1-yl)-pyrrolidin-2-yl]-methanone (5) emerged as a potent (IC(50) = 13 nM) and selective compound, with high oral bioavailability in preclinical species and low plasma protein binding. Compound 5, PF-00734200, was selected for development as a potential new treatment for type 2 diabetes.

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A series of pyrrolidine based inhibitors of dipeptidyl peptidase IV were developed from a high throughput screening hit for the treatment of type 2 diabetes. Potency, selectivity, and pharmacokinetic properties were optimized resulting in the identification of a pre-clinical candidate for further profiling.

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Inhibitors of the glucagon-like peptide-1 (GLP-1) degrading enzyme dipeptidyl peptidase IV (DPP-IV) have been shown to be effective treatments for type 2 diabetes in animal models and in human subjects. A novel series of cis-2,5-dicyanopyrrolidine alpha-amino amides were synthesized and evaluated as inhibitors of dipeptidyl peptidase IV (DPP-IV) for the treatment of type 2 diabetes. 1-({[1-(Hydroxymethyl)cyclopentyl]amino}acetyl)pyrrolidine-2,5-cis-dicarbonitrile (1c) is an achiral, slow-binding (time-dependent) inhibitor of DPP-IV that is selective for DPP-IV over other DPP isozymes and proline specific serine proteases, and which has oral bioavailability in preclinical species and in vivo efficacy in animal models.

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The serine/threonine kinase Akt/PKB plays key roles in the regulation of cell growth, survival, and metabolism. It remains unclear, however, whether the functions of individual Akt/PKB isoforms are distinct. To investigate the function of Akt2/PKBbeta, mice lacking this isoform were generated.

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