Optimization of 1,2,4-Triazolopyridines as Inhibitors of Human 11β-Hydroxysteroid Dehydrogenase Type 1 (11β-HSD-1)

Small alkyl groups and spirocyclic-aromatic rings directly attached to the left side and right side of the 1,2,4-triazolopyridines (TZP), respectively, were found to be potent and selective inhibitors of human 11β-hydroxysteroid dehydrogenase-type 1 (11β-HSD-1) enzyme. 3-(1-(4-Chlorophenyl)­cyclopropyl)-8-cyclopropyl-[1,2,4]­triazolo­[4,3-<i>a</i>]­pyridine (<b>9f</b>) was identified as a potent inhibitor of the 11β-HSD-1 enzyme with reduced Pregnane-X receptor (PXR) transactivation activity. The binding orientation of this TZP series was revealed by X-ray crystallography structure studies

11β-Hydroxysteroid Dehydrogenase Type 1 Gene Knockout Attenuates Atherosclerosis and In Vivo Foam Cell Formation in Hyperlipidemic apoE^−/− Mice

<div><h3>Background</h3><p>Chronic glucocorticoid excess has been linked to increased atherosclerosis and general cardiovascular risk in humans. The enzyme 11β-hydroxysteroid dehydrogenase type 1 (11βHSD1) increases active glucocorticoid levels within tissues by catalyzing the conversion of cortisone to cortisol. Pharmacological inhibition of 11βHSD1 has been shown to reduce atherosclerosis in murine models. However, the cellular and molecular details for this effect have not been elucidated.</p> <h3>Methodology/Principal Findings</h3><p>To examine the role of 11βHSD1 in atherogenesis, 11βHSD1 knockout mice were created on the pro-atherogenic apoE^−/− background. Following 14 weeks of Western diet, aortic cholesterol levels were reduced 50% in 11βHSD1^−/−/apoE^−/− mice vs. 11βHSD1^+/+/apoE^−/− mice without changes in plasma cholesterol. Aortic 7-ketocholesterol content was reduced 40% in 11βHSD1^−/−/apoE^−/− mice vs. control. In the aortic root, plaque size, necrotic core area and macrophage content were reduced ∼30% in 11βHSD1^−/−/apoE^−/− mice. Bone marrow transplantation from 11βHSD1^−/−/apoE^−/− mice into apoE^−/− recipients reduced plaque area 39–46% in the thoracic aorta. In vivo foam cell formation was evaluated in thioglycollate-elicited peritoneal macrophages from 11βHSD1^+/+/apoE^−/− and 11βHSD1^−/−/apoE^−/− mice fed a Western diet for ∼5 weeks. Foam cell cholesterol levels were reduced 48% in 11βHSD1^−/−/apoE^−/− mice vs. control. Microarray profiling of peritoneal macrophages revealed differential expression of genes involved in inflammation, stress response and energy metabolism. Several toll-like receptors (TLRs) were downregulated in 11βHSD1^−/−/apoE^−/− mice including TLR 1, 3 and 4. Cytokine release from 11βHSD1^−/−/apoE^−/−-derived peritoneal foam cells was attenuated following challenge with oxidized LDL.</p> <h3>Conclusions</h3><p>These findings suggest that 11βHSD1 inhibition may have the potential to limit plaque development at the vessel wall and regulate foam cell formation independent of changes in plasma lipids. The diminished cytokine response to oxidized LDL stimulation is consistent with the reduction in TLR expression and suggests involvement of 11βHSD1 in modulating binding of pro-atherogenic TLR ligands.</p> </div

Differentially expressed genes related to toll-like receptor signaling in peritoneal macrophages from Western-diet fed 11β^+/+/apoE^−/− and 11β^−/−/apoE^−/− mice.

<p>Toll-like receptors and associated signal transduction pathway genes.</p

Total plasma cholesterol and triglycerides in fasted 11βHSD1^+/+/apoE^−/− and 11βHSD1^−/−/apoE^−/− mice 14

<p> <b>weeks post Western diet. </b><b>A</b>) Plasma total cholesterol and <b>B</b>) triglycerides in male mice (n = 23, 11βHSD1^+/+/apoE^−/−; n = 13, 11βHSD1^−/−/apoE^−/−). <b>C</b>) Plasma total cholesterol and <b>D</b>) triglycerides in female mice (n = 14, 11βHSD1^+/+/apoE^−/−; n = 8, 11βHSD1^−/−/apoE^−/−). Data are pooled from three independently run in vivo studies.</p

Aortic cholesterol analysis in 11βHSD1^+/+/apoE^−/− and 11βHSD1^−/−/apoE^−/− mice.

<p>Total aortic cholesterol mass from each vessel was normalized to delipidated aorta dry weight. <b>A</b>) Aortic cholesterol levels in male 11βHSD1^+/+/apoE^−/− (n = 21) and 11βHSD1^−/−/apoE^−/− (n = 15) mice. <b>B</b>) Aortic cholesterol levels in female 11βHSD1^+/+/apoE^−/− (n = 15) and 11βHSD1^−/−/apoE^−/− (n = 8) mice. Data are pooled from three independently run in vivo studies. <b>C</b>) Aortic 7-ketocholesterol and <b>D</b>) 7β-hydroxycholesterol levels in 11βHSD1^+/+/apoE^−/− (n = 9) and 11βHSD1^−/−/apoE^−/− (n = 7) mixed-sex mice. Data are from a single independently run in vivo study. Significance vs. control: *p≤0.05.</p

Aortic root atherosclerosis.

<p><b>A</b>) Representative trichrome-stained images of lesions in the aortic root and lesion area measurements. Left image: 11βHSD1^+/+/apoE^−/− aortic root. Right image: 11βHSD1^−/−/apoE^−/− aortic root. Asterisks denote regions of acellular necrotic debris. Plot: Lesion area measurements from trichrome-stained images in 11βHSD1^+/+/apoE^−/− (n = 10) and 11βHSD1^−/−/apoE^−/− (n = 9) male mice. <b>B</b>) Intra-plaque necrotic areas. Left image: 11βHSD1^+/+/apoE^−/− aortic root plaque. Right image: 11βHSD1^−/−/apoE^−/− aortic root plaque. Asterisks denote necrotic areas within lesions. Acellularity and features of crystalline clefts were used to demarcate necrotic regions. Plot: Necrotic core area measurements from trichrome-stained images in 11βHSD1^+/+/apoE^−/− (n = 10) and 11βHSD1^−/−/apoE^−/− (n = 9) male mice. <b>C</b>) Macrophage staining via CD68 immunohistochemistry. Left image: 11βHSD1^+/+/apoE^−/− aortic root. Right image: 11βHSD1^−/−/apoE^−/− aortic root. Arrows denote CD68 positive staining. Plot: CD68 positive stained area measurements in 11βHSD1^+/+/apoE^−/− (n = 10) and 11βHSD1^−/−/apoE^−/− (n = 9) male mice. Significance vs. control: *p≤0.05. Data are pooled from two independently run in vivo studies.</p

In vivo foam cell analysis.

<p><b>A</b>) Peritoneal macrophage total cholesterol mass normalized to cell count from hyperlipidemic 11βHSD1^+/+/apoE^−/− (n = 13) and 11βHSD1^−/−/apoE^−/− (n = 16) mixed-sex mice. <b>B</b>) Peritoneal macrophages (MΦ) harvested by lavage from 11βHSD1^+/+/apoE^−/− (left upper and lower images) and 11βHSD1^−/−/apoE^−/− (right upper and lower images) mice stained with oil red O and hematoxylin. Magnification of top images 40X and lower images 100X. Data are pooled from two independently run studies. Significance vs. control: *p≤0.05.</p

Discovery of Clinical Candidate 2‑((2<i>S</i>,6<i>S</i>)‑2-Phenyl-6-hydroxyadamantan-2-yl)-1-(3′-hydroxyazetidin-1-yl)ethanone [BMS-816336], an Orally Active Novel Selective 11β-Hydroxysteroid Dehydrogenase Type 1 Inhibitor

BMS-816336 (<b>6n-2</b>), a hydroxy-substituted adamantyl acetamide, has been identified as a novel, potent inhibitor against human 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) enzyme (IC₅₀ 3.0 nM) with >10000-fold selectivity over human 11β-hydroxysteroid dehydrogenase type 2 (11β-HSD2). <b>6n-2</b> exhibits a robust acute pharmacodynamic effect in cynomolgus monkeys (ED₅₀ 0.12 mg/kg) and in DIO mice. It is orally bioavailable (%<i>F</i> ranges from 20 to 72% in preclinical species) and has a predicted pharmacokinetic profile of a high peak to trough ratio and short half-life in humans. This ADME profile met our selection criteria for once daily administration, targeting robust inhibition of 11β-HSD1 enzyme for the first 12 h period after dosing followed by an “inhibition holiday” so that the potential for hypothalamic–pituitary–adrenal (HPA) axis activation might be mitigated. <b>6n-2</b> was found to be well-tolerated in phase 1 clinical studies and represents a potential new treatment for type 2 diabetes, metabolic syndrome, and other human diseases modulated by glucocorticoid control