Effect of Glucocorticoid and 11β-Hydroxysteroid-Dehydrogenase Type 1 (11β-HSD1) in Neurological and Psychiatric Disorders

Role of 11β-Hydroxysteroid Dehydrogenase and Mineralocorticoid Receptor on Alzheimer's Disease Onset: A Systematic Review

The role of 11β-HSD1 in Alzheimer's disease (AD) has garnered significant attention due to its involvement in glucocorticoid metabolism, neuroinflammation, and cognitive decline. This review explores the current understanding of 11β-HSD1 in AD, examining genetic, preclinical, and clinical research. Genetic studies have identified 11β-HSD1 polymorphisms that may influence AD risk, although findings remain inconsistent. Mechanistically, 11β-HSD1 promotes neurodegeneration through the dysregulation of glucocorticoid activity, contributing to hippocampal atrophy, amyloid plaque formation, and tau pathology. Preclinical studies have shown that 11β-HSD1 inhibitors offer neuroprotective effects, including enhanced cognitive function, reduced inflammation, and improved mitochondrial activity. However, clinical trials, including those involving ABT-384 and Xanamem, have produced mixed results, with no substantial cognitive improvements despite effective enzyme inhibition. These inconsistencies highlight the complexity of AD and the challenges in translating preclinical findings into clinical outcomes. Moreover, while 11β-HSD1 inhibition holds therapeutic potential, other strategies targeting neuroinflammation, autophagy, and glucocorticoid signaling are also being explored. Ongoing research is focusing on optimizing 11β-HSD1 inhibitors, identifying biomarkers for patient selection, and investigating combination therapies to enhance treatment efficacy. Ultimately, 11β-HSD1's role in AD presents a promising therapeutic target, but further studies are required to fully understand its potential in managing the disease.

Clinical Pharmacology and Approach to Dose Selection of Emestedastat, a Novel Tissue Cortisol Synthesis Inhibitor for the Treatment of Central Nervous System Disease

This review demonstrates the value of central pharmacodynamics (PD), including positron emission tomography (PET) and computerized cognitive testing, to supplement pharmacokinetic (PK) and peripheral PD for determining the target dose range for clinical efficacy testing of emestedastat, an 11β-hydroxysteroid dehydrogenase 1 (11β-HSD1) inhibitor. Combined data from 6 clinical trials in cognitively normal volunteers and patients with Alzheimer disease included a population PK model, endocrine PD, a human PET trial (11β-HSD1 brain imaging), and computerized cognitive testing. PK and PET findings were similar in volunteers and patients with Alzheimer disease. PK modeling suggested that 20 mg daily would be optimal to maintain cerebrospinal fluid concentrations above the brain half maximal inhibitory concentration. However, subsequent PET scanning suggested that emestedastat doses of 10 or even 5 mg daily may be sufficient to adequately inhibit 11β-HSD1. With once-daily doses of 5-20 mg in cognitively normal, older volunteers, a consistent pattern of pro-cognitive benefit, without dose-response, was seen as improvement in attention and working memory but not episodic memory. Thus, emestedastat therapeutic activity might be attained at doses lower than those predicted from cerebrospinal fluid drug levels. Doses as low as 5 mg daily may be efficacious and were studied in subsequent trials.

IL17RB genetic variants are associated with acamprosate treatment response in patients with alcohol use disorder: A proteomics-informed genomics study

Acamprosate is a Food and Drug Administration (FDA) approved medication for the treatment of alcohol use disorder (AUD). However, only a subset of patients achieves optimal treatment outcomes. Currently, no biological measures are utilized to predict response to acamprosate treatment. We applied our established pharmaco-omics informed genomics strategy to identify potential biomarkers associated with acamprosate treatment response. Specifically, our previous open-label acamprosate clinical trial recruited 442 patients with AUD who were treated with acamprosate for three months. We first performed proteomics using baseline plasma samples to identify potential biomarkers associated with acamprosate treatment outcomes. Next, we applied our established "proteomics-informed genome-wide association study (GWAS)" research strategy, and identified 12 proteins, including interleukin-17 receptor B (IL17RB), associated with acamprosate treatment response.​ A GWAS for IL17RB concentrations identified several genome-wide significant signals. Specifically, the top hit single nucleotide polymorphism (SNP) rs6801605 with a minor allele frequency of 38% in the European American population mapped 4 kilobase (Kb) upstream of IL17RB, and intron 1 of the choline dehydrogenase (CHDH) gene on chromosome 3 (p: 4.8E-20). The variant genotype (AA) for the SNP rs6801605 was associated with lower IL17RB protein expression. In addition, we identified a series of genetic variants in IL17RB that were associated with acamprosate treatment outcomes. Furthermore, the variantgenotypes for all of those IL17RB SNPs were protective for alcohol relapse. Finally, we demonstrated that the basal level of mRNA expression of IL17RB was inversely correlated with those of nuclear factor-κB (NF-κB) subunits, and a significantly higher expression of NF-κB subunits was observed in AUD patients who relapsed to alcohol use. In summary, this study illustrates that IL17RB genetic variants might contribute to acamprosate treatment outcomes. This series of studies represents an important step toward generating functional hypotheses that could be tested to gain insight into mechanisms underlying acamprosate treatment response phenotypes. (The ClinicalTrials.gov Identifier: NCT00662571).

Memory deficits in a juvenile rat model of type 1 diabetes are due to excess 11β-HSD1 activity, which is upregulated by high glucose concentrations rather than insulin deficiency

AIMS/HYPOTHESIS

Children with diabetes may display cognitive alterations although vascular disorders have not yet appeared. Variations in glucose levels together with relative insulin deficiency in treated type 1 diabetes have been reported to impact brain function indirectly through dysregulation of the hypothalamus-pituitary-adrenal axis. We have recently shown that enhancement of glucocorticoid levels in children with type 1 diabetes is dependent not only on glucocorticoid secretion but also on glucocorticoid tissue concentrations, which is linked to 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) activity. Hypothalamus-pituitary-adrenal axis dysfunction and memory alteration were further dissected in a juvenile rat model of diabetes showing that excess 11β-HSD1 activity within the hippocampus is associated with hippocampal-dependent memory deficits. Here, to investigate the causal relationships between diabetes, 11β-HSD1 activity and hippocampus-dependent memory deficits, we evaluated the beneficial effect of 11β-HSD1 inhibition on hippocampal-related memory in juvenile diabetic rats. We also examined whether diabetes-associated enhancement of hippocampal 11β-HSD1 activity is due to an increase in brain glucose concentrations and/or a decrease in insulin signalling.

METHODS

Diabetes was induced in juvenile rats by daily i.p. injection of streptozotocin for 2 consecutive days. Inhibition of 11β-HSD1 was obtained by administrating the compound UE2316 twice daily by gavage for 3 weeks, after which hippocampal-dependent object location memory was assessed. Hippocampal 11β-HSD1 activity was estimated by the ratio of corticosterone/dehydrocorticosterone measured by LC/MS. Regulation of 11β-HSD1 activity in response to changes in glucose or insulin levels was determined ex vivo on acute brain hippocampal slices. The insulin regulation of 11β-HSD1 was further examined in vivo using virally mediated knockdown of insulin receptor expression specifically in the hippocampus.

RESULTS

Our data show that inhibiting 11β-HSD1 activity prevents hippocampal-related memory deficits in diabetic juvenile rats. A significant increase (53.0±9.9%) in hippocampal 11β-HSD1 activity was found in hippocampal slices incubated in high glucose conditions (13.9 mmol/l) vs normal glucose conditions (2.8 mmol/l) without insulin. However, 11β-HSD1 activity was not affected by variations in insulin concentration either in the hippocampal slices or after a decrease in hippocampal insulin receptor expression.

CONCLUSIONS/INTERPRETATION

Together, these data demonstrate that an increase in 11β-HSD1 activity contributes to memory deficits observed in juvenile diabetic rats and that an excess of hippocampal 11β-HSD1 activity stems from high glucose levels rather than insulin deficiency. 11β-HSD1 might be a therapeutic target for treating cognitive impairments associated with diabetes.

Spirocyclic Iodonium Ylides for Fluorine-18 Radiolabeling of Non-Activated Arenes: From Concept to Clinical Research

Positron emission tomography (PET) is a powerful imaging tool for drug discovery, clinical diagnosis, and monitoring of disease progression. Fluorine-18 is the most common radionuclide used for PET, but advances in radiotracer development have been limited by the historical lack of methodologies and precursors amenable to radiolabeling with fluorine-18. Radiolabeling of electron-rich (hetero)aromatic rings remains a long-standing challenge in the production of PET radiopharmaceuticals. In this personal account, we discuss the history of spirocyclic iodonium ylide precursors, from inception to applications in clinical research, for the incorporation of fluorine-18 into complex non-activated (hetero)aromatic rings.

Effects and Stress-Relieving Mechanisms of Dark Tea Polysaccharide in Human HaCaT Keratinocytes and SZ95 Sebocytes

A new skincare application scenario for dark tea, a unique and post-fermented tea popular in the health food industry, was developed in this paper. The effects of dark tea polysaccharide (DTP) on stress-induced skin problems and its mechanism of action were investigated by modeling cortisone-induced stress injury in human HaCaT keratinocytes and SZ95 sebaceous gland cells. The results showed a reduced cortisol conversion induced by cortisone under the action of DTP with a concentration of 200 μg/mL, probably by inhibiting the expression of the HSD11B1 enzyme. DTP was also able to suppress the cortisone-induced elevation of lipid levels in SZ95 sebocytes at this concentration. In addition, the composition and structure of DTP were verified by ultrafiltration, ultraviolet-visible spectrophotometry (UV-VIS), high-performance anion-exchange chromatography with pulsed amperometric detection (HPAEC-PAD) and infrared spectroscopy. In brief, DTP has a unique and significant stress-relieving effect, which provides new ideas for the development of new ingredients for the skin care industry.