Biology subjects

Macarelli, V.

Publications and source records attributed to Macarelli, V..

2 recordsLinked to original sources

bioRxiv2024

GLP1R agonists activate human POMC neurons

Drugs like semaglutide (a.k.a. Ozempic/Wegovy) that activate the glucagon-like peptide-1 receptor (GLP-1R) are a promising therapy for obesity and type 2 diabetes (T2D). Animal studies suggest that these drugs likely function by stimulating GLP-1R on appetite-suppressing neuron populations in the brain, but it is still unclear how they act to reduce food intake in humans. We therefore generated appetite-regulatory hypothalamic neurons from human pluripotent stem cells (hPSCs) to study their responses to GLP-1R agonists by calcium imaging and electrophysiology. We found that hPSC-derived proopiomelanocortin (POMC) and other hypothalamic neuron subtypes expressed GLP1R mRNA, and many of these neurons robustly responded to GLP-1R agonists by membrane depolarization, increased action potential firing, and extracellular calcium influx that persisted long after agonist withdrawal. The observed GLP-1R-induced response was likely mediated by the activation of PKA and L-type calcium channels, and led to significant changes in gene expression. These findings provide mechanistic insight into how GLP-1R agonists may suppress appetite in humans.

neuroscience↗

bioRxiv2024

A short sequence targets transmembrane proteins to primary cilia

Primary cilia are finger-like sensory organelles that extend from the bodies of most cell types and have a distinct lipid and protein composition from the plasma membrane. This partitioning is maintained by a diffusion barrier that restricts the entry of non-ciliary proteins, and allows the selective entry of proteins harboring a ciliary targeting sequence (CTS). However, CTSs are not stereotyped, and previously-reported sequences are insufficient to drive efficient ciliary localization across diverse cell types. Here, we describe a short peptide sequence that efficiently targets transmembrane proteins to primary cilia in all tested cell types, including human neurons. We generate human induced pluripotent stem cell (hiPSC) lines stably expressing a transmembrane construct bearing an extracellular HaloTag and intracellular fluorescent protein, that enables bright, specific labeling of primary cilia in neurons and other cell types. We demonstrate the utility of this resource by developing an image analysis pipeline for the automated measurement of primary cilia to detect changes in their length.

cell biology↗