Changes in the transcriptomic landscape of the hypothalamus in Prader-Willi Syndrome

Prader-Willi syndrome (PWS) is a complex genetic disorder with distinct developmental stages. In infancy PWS manifests as failure to thrive, hypotonia, and difficulty feeding. During early childhood, a shift occurs that leads to hyperphagia, behavioral challenges, and endocrine disruption. Many of these challenges are rooted in hypothalamic dysfunction, which results in disruption of numerous endocrine processes, including glucose homeostasis, stress responses, growth, and regulation of circadian rhythm. Previous work on PWS has focused on clinical characterization and treatment to improve phenotypic outcome, which has improved outcomes for patients, although the specific mechanisms that underlie many PWS symptoms remain unresolved. To date, animal models of PWS have failed to recapitulate the full scope of the disorder, adding additional challenge to mechanistic characterization of the syndrome. This project aims to address this gap in knowledge by examining the spatial transcriptomic landscape of hypothalamic neurons from individuals with PWS. While some work has been done to examine transcriptional changes in the hypothalamus of these patients through single-cell sequencing, much is left to be explored. For this project, we employed Nanostring’s CosMX Spatial Molecular Imaging (SMI) technology. CosMX SMI offers for high resolution mapping of gene expression within tissues, and allows for the use of formalin fixed, paraffin embedded tissue, which greatly expands the pool of available tissue. We obtained hypothalamic tissue from individuals with PWS and age, sex, and race matched unaffected controls from tissue banks. Differential expression analysis of neurons in PWS and controls showed differences in metabolism and endocrine pathways. Importantly, we found that a subcluster of corticotropin-releasing hormone positive (CRH+) neurons was absent in PWS patients. The closest neuronal neighbor of these neurons was a cluster of neurons with downregulated ACTN4 expression in PWS donors but not in unaffected controls. This could indicate alterations in secretion or the cytoskeletal structure in PWS patients. These differences could potentially be influenced by changes in cellular neighborhood, or the way that cells are positioned around each other. We hope that these findings begin to reveal cellular processes that may contribute to the PWS phenotype, especially those that may be responsible for disrupted neuroendocrine signaling that is seen in these patients. This work is supported through funding provided by the Foundation for Prader-Willi Research This abstract was presented at the American Physiology Summit 2025 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.