Type 1 11 β-hydroxysteroid Dehydrogenase as Universal Drug Target in Metabolic Diseases?

Udo      Oppermann

doi:10.2174/187153006778250000

Abstract

Glucocorticoid hormones play essential roles in adaptation to stress, regulation of metabolism and inflammatory responses. Their effects primarily depend on their binding to intracellular receptors leading to altered target gene transcription as well as on cell-type specific biotransformation between 11β -hydroxy glucocorticoids and their 11- oxo metabolites. The latter effect is accomplished by two different 11 β-hydroxysteroid dehydrogenase isozymes, constituting a shuttle system between the receptor ligand cortisol and its non-binding precursor cortisone. Whereas the type 1 enzyme (11β-HSD1) is in vitro a NADP(H)- dependent bidirectional enzyme, it reduces in most instances in vivo cortisone to active cortisol. The type 2 enzyme is an exclusive NAD+ dependent dehydrogenase of glucocorticoids, thus “protecting” the mineralocorticoid receptor against illicit occupation by cortisol. Inhibition of tissue-specific glucocorticoid activation by 11 β-HSD1 constitutes a promising target in the treatment of metabolic and cardiovascular diseases. Pharmacological inhibition leads in animal models to lowered hepatic glucose production and increased insulin sensitivity, the primary goals in therapy of diabetes mellitus. Importantly, 11 β-HSD1 activity appears to be intrinsically linked to all features of the metabolic syndrome, which could at least in animal experiments be modulated by use of synthetic selective inhibitors. Importantly, these features include not only insulin resistance but also dyslipidemia, obesity and arterial hypertension. Animal studies and pharmacological experiments suggest further unrelated target areas, for example improvement of cognitive function and treatment of glaucoma, due to the role of glucocorticoids and cellular activation by 11 β-HSD1 in these pathologies. The recent development of specific 11 β-HSD1 inhibitors coupled with advances on structural knowledge and regulation of the 11 β-HSD1 target has undoubtedly promoted the understanding of glucocorticoid control of metabolic regulation. Taken together, it appears that inhibitors against 11 -HSD1 constitute a promising avenue for novel treatment strategies against the underlying causes of cardiovascular and other metabolic diseases.

Keywords: Glucocorticoid metabolism, 11 β-hydroxysteroid dehydrogenase, metabolic disease, drug development

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