MECHANISMS MEDIATING INTERNALIZATION AND TRANSPORT OF GHRELIN IN HYPOTHALAMIC TANYCYTES

IVANA M. GÓMEZ; DANIEL CASTROGIOVANNI; MAIA URIARTE; MARIO PERELLÓ; PABLO NICOLÁS DE FRANCESCO

Mar del Plata

Congreso; REUNIÓN CONJUNTA SAIC- SAI&FAIC- SAFIS 2022; 2022

SAIC- SAI- SAFIS

Hypothalamic tanycytes are polarized glial cells that line the base of the third ventricle. Their somas contact the cerebrospinal fluid (CSF), while their terminal side (endfeet) contact the capillaries of the blood-brain barrier (BBB) or the fenestrated capillaries of the median eminence, forming a relevant anatomical interface for the transport of molecules between blood and CSF. Usingmice and rats, we recently described that tanycytes internalize the orexigenic hormone ghrelin in vivo and in vitro. Here, we study the cellular mechanisms of ghrelin uptake by hypothalamic tanycytes and its transport direction. Specifically, we incubated primary cultures of rat hypothalamic tanycytes with a fluorescent variant of ghrelin (Fr-ghrelin) in basal conditions or after pharmacological blockage of either clathrin-mediated internalization using Pitstop, or intracellular transport using colchicine. We also coincubated tanycytes with Fr-ghrelin and native ghrelin. We then quantified fluorescence intensity in soma, process and endfeet of each cell. Data were compared using Kruskal Wallis test with Dunn’s post hoc test. We found that intracellular fluorescence: 1) is found predominantly in the soma of tanycytes after a 5 min incubation (K-W p