Abstract Nontumoral cortisol dysregulation in obese individuals is associated with many facets of metabolic syndrome, including central adiposity, diabetes mellitus (T2DM), dyslipidemia, and hypertension. Glucocorticoid availability and function at the cell/tissue level are classically regulated by 11-beta hydroxysteroid dehydrogenase type (11β-HSD) enzymes. The 11β-HSD1 enzyme is expressed primarily in the liver and adipose tissue (AT) where cortisone in converted into its active form, cortisol. 11β-HSD1 expression in AT promotes adipocyte proliferation and hypertension, leading to the development of abdominal obesity and comorbidities. The 11β-HSD1 enzyme is a key therapeutic target for modulating obesity and associated metabolic disorders.In response to this need, our research aimed to design and characterize a family of nonsteroidal compounds displaying specific and selective inhibition of the 11β-HSD1 enzyme. For this purpose, we designed, synthetized, and characterized a family of adamantyloxadiazole compounds to selectively inhibit the human 11β-HSD1 enzyme that are henceforth designated sequentially from A to N (14 compounds). Our newly synthesized compounds were designed in silico and synthesized via retrosynthesis. We tested the following properties of our novel compounds: (1) their biopharmaceutical properties, (2) their inhibitory potency (IC50) over 11β-HSD1 reductase activity in cell-free assays, and (3) their relative inhibitory potency and IC50 in human adipocytes.Biopharmaceutical characterization of the compounds revealed high transcellular permeability and no interaction with P-glycoprotein, a known efflux pump that decreases oral systemic and central exposure, for Compounds J and L . In vitro studies of the inhibition of the 11β-HSD1 enzyme via cell-free and microsome-based assays indicated significant inhibitory potency, with optimal specificity and selectivity observed at the nanomolar level, highlighting both the IC50 values of Compound J (11,8 nM) and Compound L (3,9 nM), which also preserve 11b-HSD oxidase activities (> 90%). In human adipocytes, 1 µM Compounds E , J and L demonstrated a high potency of 11β-HSD1 inhibition, near 40–60%, compared to 1 µM inhibitor carbenoxolone, which showed approximately a 90% inhibition.The preclinical evaluation of these adamantyloxadiazole derivatives revealed their potential as effective inhibitors of the 11β-HSD1 enzyme, with Compounds E , J and L showing particularly relevant performance in vitro . These findings support the progression of in vivo studies to further explore their therapeutic potential in treating obesity and associated metabolic disorders.

Early life stress (ELS) is a major risk factor for developing psychiatric disorders, with glucocorticoids (GCs) implicated in mediating its effects in shaping adult phenotypes. In this process, exposure to high levels of developmental GC (hdGC) is thought to induce molecular changes that prime differential adult responses. However, identities of molecules targeted by hdGC exposure are not completely known. Here, we describe lifelong molecular consequences of hdGC exposure using a newly developed zebrafish double-hit stress model, which shows altered behaviors and stress hypersensitivity in adulthood. We identify a set of primed genes displaying altered expression only upon acute stress in hdGC-exposed adult fish brains. Interestingly, this gene set is enriched in risk factors for psychiatric disorders in humans. Lastly, we identify altered epigenetic regulatory elements following hdGC exposure. Thus, our study provides comprehensive datasets delineating potential molecular targets mediating the impact of hdGC exposure on adult responses.
© 2024 The Author(s).

Early life stress (ELS) exposure alters stress susceptibility in later life and affects vulnerability to stress-related disorders, but how ELS changes the long-lasting responsiveness of the stress system is not well understood. Zebrafish provides an opportunity to study conserved mechanisms underlying the development and function of the stress response that is regulated largely by the neuroendocrine hypothalamus-pituitary-adrenal/interrenal (HPA/I) axis, with glucocorticoids (GC) as the final effector. In this study, we established a method to chronically elevate endogenous GC levels during early life in larval zebrafish. To this end, we employed an optogenetic actuator, beggiatoa photoactivated adenylyl cyclase, specifically expressed in the interrenal cells of zebrafish and demonstrate that its chronic activation leads to hypercortisolaemia and dampens the acute-stress evoked cortisol levels, across a variety of stressor modalities during early life. This blunting of stress-response was conserved in ontogeny at a later developmental stage. Furthermore, we observe a strong reduction of proopiomelanocortin (pomc)-expression in the pituitary as well as upregulation of fkbp5 gene expression. Going forward, we propose that this model can be leveraged to tease apart the mechanisms underlying developmental programming of the HPA/I axis by early-life GC exposure and its implications for vulnerability and resilience to stress in adulthood.
© 2024 The Authors. European Journal of Neuroscience published by Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

Exposure to excess glucocorticoid (GC) during early development is implicated in adult dysfunctions. Reduced adult hippocampal neurogenesis is a well-known consequence of exposure to early life stress or elevated GC, however the effects on neurogenesis during development and effects on other brain regions are not well understood. Using an optogenetic zebrafish model, here we analyse the effects of GC exposure on neurogenesis during development in the whole brain. We identify that the hypothalamus is a highly GC-sensitive region where elevated GC causes precocious development. This is followed by failed maturation and early decline accompanied by impaired feeding, growth, and survival. In GC-exposed animals, the developmental trajectory of hypothalamic progenitor cells is strikingly altered, potentially mediated by direct regulation of transcription factors such as rx3 by GC. Our data provide cellular and molecular level insight into GC-induced alteration of the hypothalamic developmental trajectory, a process crucial for health across the life-course.
© 2024. The Author(s).

Stress alters social functioning in a complex manner. An important variable determining the final effects of stress is stressor intensity. However, the precise relationship between stressor intensity and social behavior is not well understood. Here, we investigate the effects of varying acute stressor intensity exposure on social behavior using adult zebrafish. We first establish a novel test using adult zebrafish that allows distinguishing fish's drive to approach a social cue and its ability to engage and maintain social interaction within the same behavioral paradigm. Next, we combined this test with a new method to deliver an acute stress stimulus of varying intensities. Our results show that both social approach and social maintenance are reduced in adult zebrafish on acute stress exposure in an intensity-dependent manner. Interestingly, lower stress intensity reduces social maintenance without affecting the social approach, while a higher stress level is required to alter social approach. These results provide evidence for a direct correlation between acute stressor intensity and social functioning and suggest that distinct steps in social behavior are modulated differentially by the acute stress level.
Copyright © 2023 Cook et al.