Sirolimus induces depletion of intracellular calcium stores and mitochondrial dysfunction in pancreatic beta cells

Angela Lombardi, Jessica Gambardella, Xue Liang Du, Daniela Sorriento, Maurizio Mauro, Guido Iaccarino, Bruno Trimarco, Gaetano Santulli

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Sirolimus (rapamycin) is an immunosuppressive drug used in transplantation. One of its major side effects is the increased risk of diabetes mellitus; however, the exact mechanisms underlying such association have not been elucidated. Here we show that sirolimus impairs glucose-stimulated insulin secretion both in human and murine pancreatic islets and in clonal ß cells in a dose- and timedependent manner. Importantly, we demonstrate that sirolimus markedly depletes calcium (Ca2+) content in the endoplasmic reticulum and significantly decreases glucose-stimulated mitochondrial Ca2+ uptake. Crucially, the reduced mitochondrial Ca2+ uptake is mirrored by a significant impairment in mitochondrial respiration. Taken together, our findings indicate that sirolimus causes depletion of intracellular Ca2+ stores and alters mitochondrial fitness, eventually leading to decreased insulin release. Our results provide a novel molecular mechanism underlying the increased incidence of diabetes mellitus in patients treated with this drug.

Original languageEnglish (US)
Article number15823
JournalScientific Reports
StatePublished - Jan 1 2017


ASJC Scopus subject areas

  • General

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