The role of AgRP neurons in the metabolic and reproductive complications of Cushing's Syndrome

/ABSTRACT Cushing’s syndrome results from chronic exposure to excess glucocorticoids, which can be from an endogenous source of autonomous cortisol production or from exogenous administration of glucocorticoids. Chronic hypercortisolism leads to multiple morbidities, including metabolic syndrome and infertility, as well as increased mortality. These comorbidities may not be resolved even after successful treatment and remission. The neuronal mechanisms regulating fertility are tightly linked to energy balance. Hypothalamic neurons expressing agouti-related peptide (AgRP) are activated after fasting and have been proposed as the link between metabolism and reproduction. Increased activity of this hunger pathway leads to reduced GnRH/LH pulse generation and subsequently to impaired fertility. Chronic glucocorticoid exposure on the other hand, which is known to cause hyperphagia and infertility, has been shown to increase AgRP activity, as well. This proposal aims to explore whether glucocorticoids act directly on AgRP neurons to mediate the metabolic and reproductive effects. First, I will elucidate the role of AgRP neurons in these glucocorticoid-induced effects. Using a chemogenetic approach I will determine if the inhibition of AgRP neurons can prevent or ameliorate reproductive and metabolic impairments. Then, I will generate a mouse model with conditional deletion of glucocorticoid receptor (GR) in AgRP neurons to explore their resistance to developing Cushing’s phenotype under chronic glucocorticoid treatment. In Agrp-cre mice treated with glucocorticoids I will selectively delete GR in AgRP neurons (via CRISPR approach) after developing the Cushing’s phenotype to improve fertility and obesity. Finally given the fact that Cushing’s syndrome is more prevalent in women and these complications can persist in many patients even after remission, I hypothesize that chronic glucocorticoid exposure will mediate transcriptomic and epigenetic modifications within the GR-gene regulatory network of the arcuate nucleus of hypothalamus in a sex-dependent manner and among the affected genes will be genes associated with energy balance and reproduction. Using RNA seq analysis and a highly sensitive fluorescent in situ hybridization I will try to identify differentially expressed genes within the AgRP neurons after chronic glucocorticoid exposure. To further investigate potential long-lasting GR conformational changes, I will perform chromatin immunoprecipitation sequencing analysis. In summary, the overarching goals of this proposal are to elucidate the precise mechanisms by which chronic glucocorticoid exposure affects metabolism and reproduction, focusing on the role of AgRP neurons, and to advance our comprehension of the transcriptomic and epigenetic alterations induced by chronic glucocorticoid exposure. Successful completion of this project may identify potential therapeutic targets to improve the quality of life for patients with Cushing’s syndrome. Furthermore, it may discover unique biomarkers in genetically susceptible individuals, thereby aiding in the prediction of patients at risk of developing these comorbidities. Project Number: 1K08HD116931-01A1 | Fiscal Year: 2026 | NIH Institute/Center: Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) | Principal Investigator: George Stamatiades | Institution: BRIGHAM AND WOMEN'S HOSPITAL, BOSTON, MA | Award Amount: $167,400 | Activity Code: K08 | Study Section: Special Emphasis Panel[ZRG1 EMS-S (90)] View on NIH RePORTER: https://reporter.nih.gov/project-details/11300785