The interaction of amyloid beta (Aβ) peptide with cell membranes has been shown to be influenced by Aβ conformation, membrane physicochemical properties and lipid composition. However, the effect of cholesterol and its oxidized derivatives, oxysterols, on Aβ-induced neurotoxicity to membranes is not fully understood. We employed here model membranes to investigate the localization of Aβ in membranes and the peptide-induced membrane dynamics in the presence of cholesterol and 7-ketocholesterol (7keto) or 25-hydroxycholesterol (25OH). Our results have indicated that oxysterols rendered membranes more sensitive to Aβ, in contrast to role of cholesterol in inhibiting Aβ/membrane interaction. We have demonstrated that two oxysterols had different impacts owing to distinct positions of the additional oxygen group in their structures. 7keto-containing cell-sized liposomes exhibited a high propensity toward association with Aβ, while 25OH systems were more capable of morphological changes in response to the peptide. Furthermore, we have shown that 42-amino acid Aβ (Aβ-42) pre-fibril species had higher association with membranes, and caused membrane fluctuation faster than 40-residue isoform (Aβ-40). These findings suggest the enhancing effect of oxysterols on interaction of Aβ with membranes and contribute to clarify the harmful impact of cholesterol on Aβ-induced neurotoxicity by means of its oxidation.

A novel series of RORγ inhibitors was identified starting with the HTS hit 1. After SAR investigation based on a prospective consideration of two drug-likeness metrics, ligand efficiency (LE) and fraction of sp 3 carbon atoms (Fsp 3 ), significant improvement of metabolic stability as well as reduction of CYP inhibition was observed, which finally led to discovery of a selective and orally efficacious RORγ inhibitor 3z.KEYWORDS: Th17, immunological diseases, nuclear receptor, RORγ, ligand efficiency (LE), fraction of sp 3 carbon atoms (Fsp 3 )T wo decades after the discovery of Th1 and Th2 cells, a third subset of T helper cells called Th17 cells was identified and has drawn considerable attention since it was suggested to play a central role in the pathogenesis of various autoimmune diseases such as psoriasis and rheumatoid arthritis. 1,2 Among several regulatory pathways in which Th17 development and function are involved, the one regulated by the nuclear receptor RORγ appears to be crucial for controlling the differentiation and function. 3 Given its validity as an emerging drug target for treatment of immunological diseases, many research groups have made significant efforts in the discovery of RORγ modulators in recent years. 4−19 Since starting our RORγ inhibitor program in 2003, we discovered several structurally diverse hits after a HTS campaign. 20 From these hits we selected compound 1 as the first hit-to-lead series for optimization. In addition to being reasonably potent against RORγ (hLUC EC 50 = 1.7 μM, FRET EC 50 = 0.85 μM), compound 1 also demonstrated >20-fold selectivity over five nuclear receptors (hRORα, hFXR, hRXRα, hPR, and hPPARγ) and was structurally unique in comparison to other nuclear receptor modulators. 16−18 However, this compound has several drawbacks. For example, the microsomal stability in liver microsomes is poor with only 18% remaining at 10 min in human liver microsomes. It also has a modest time-dependent human CYP3A4 inhibition (IC 50 = 4 μM) probably due to some reactive metabolites formed by the oxidation of 1. The ligand efficiency is only 0.25, far below the literature consensus value (0.30) for a drug-like molecule. 21 The concept of ligand efficiency (LE) was first introduced by Kuntz 22 and is widely accepted as a reliable index of drug-like qualities. 23 Improvement of LE inevitably results in lower molecular weight and higher potency. We reasoned that a strategy of increasing LE and lowering the lipophilicity should therefore significantly improve the drug-like properties of compound 1. In addition, compound 1 is a rather flat molecule with a fraction of saturated carbons (Fsp 3 ) of 0.24. Fsp 3 is a newer index representing drug-likeness. 24 Lovering et al. pointed out that a decrease of Fsp 3 value would result in an increased incidence of CYP inhibition. 25 The desired Fsp 3 value is over 0.47 according to the literature. 24 Thus, we considered that improvement of the poor Fsp 3 value of compound 1 would be a rational way to overcome the CYP inhibi...

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Obesity, hyperglycemia, hyperlipidemia, and diabetes-associated complications appear at younger ages (6-8 weeks) in the male Spontaneously Diabetic Torii-Lepr fa (SDTfa/fa) rat than in the male original SDT (SDT-+/+) rat. However, the incidence and progression of diabetes mellitus and diabetic complications in the female SDT-fa/fa rat have not been reported in detail. In the present study, the pathophysiological features of the female SDT-fa/ fa rat were examined, and compared with those of the female SDT-+/+ rat. Female SDT-fa/ fa rats showed hyperphagia, obesity, hyperglycemia, and hyperlipidemia from 5 or 6 weeks of age, and hyperinsulinemia was observed from 5 to 12 weeks. Pathological changes pancreatic islets were observed from 8 weeks. Renal function parameters, such as urine volume and urinary protein, increased from 16 weeks, and pathological findings in the renal tubule, and cataracts were also observed from 16 weeks. Increases of visceral and subcutaneous fats were obvious during the observation period. In pair-feeding with SDT-+/+ rats, SDT-fa/fa rats showed improved hyperglycemia and hypertriglycemia, but hypercholesterolemia was not entirely improved during the study period. Female SDT-fa/fa rats showed diabetes mellitus and diabetes-associated complications at young ages, and fat accumulation was remarkable. Suppression of hyperphagia in SDT-fa/fa rats was effective at improving hyperglycemia and hypertriglycemia. In conclusion, the female SDT-fa/fa rat has the potential to become an important animal model of type 2 diabetes mellitus with obesity, especially for women, for which few models currently exist.

Inhibitors of microsomal triglyceride transfer protein (MTP) expressed in the liver and small intestine are potential candidates for lipid-lowering agents. However, inhibition of hepatic MTP could lead to significant safety issues such as fatty liver disease. To develop a specific inhibitor of intestinal MTP, JTT-130, was designed to be rapidly hydrolyzed in the absorption process. Here, we describe JTT-130, an intestine-specific MTP inhibitor, and evaluate its pharmacological properties. In in vitro metabolic stability tests, JTT-130 was readily hydrolyzed during incubation with liver S9 from humans, hamsters, and rats. In an in vitro triglyceride (TG) transfer assay with human intestinal MTP, JTT-130 potently inhibited TG transfer activity with an IC 50 value of 0.83 nM. When orally administered to hamsters, JTT-130 significantly suppressed an increase in chylomicron-TG after olive oil loading at 0.3 mg/kg and above but did not inhibit TG secretion from the liver at doses of up to 1000 mg/kg, indicating an inhibitory action highly specific for the small intestine. In rats orally administered [14 C]triolein, JTT-130 potently suppressed an increase in blood 14 C radioactivity and increased 14 C radioactivity in the upper small intestine and the intestinal lumen. In hyperlipidemic hamsters fed a high-fat and high-cholesterol diet, repeated dosing with JTT-130 for 2 weeks reduced TG and cholesterol levels in the plasma and TG content in the liver. These results indicated that JTT-130 is a potent inhibitor specific to intestinal MTP and suggested that JTT-130 would be a useful compound for the treatment of dyslipidemia without inducing hepatotoxicity.