title: Evidence for a role of frataxin in pancreatic islets isolated from multi-organ donors with and without type 2 diabetes mellitus.
abstract: Frataxin (FXN) is a mitochondrial protein involved in iron metabolism and in the modulation of reactive oxygen and/or nitrogen species production. No information is currently available as for the role of frataxin in isolated human pancreatic islets. We studied islets from pancreases of multi-organ donors with (T2DM) and without (Ctrl) Type 2 diabetes mellitus. In these islets, we determined FXN gene and protein expression by qualitative and quantitative Real-Time RT-PCR, nitrotyrosine concentration, and insulin release in response to glucose stimulation (SI). FXN gene and protein were expressed in human islets, though the level of expression was much lower in T2DM islets. The latter also had lower insulin release and higher concentration of nitrotyrosine. A positive correlation was apparent between SI and FXN gene expression, while a negative correlation was found between nitrotyrosine islet concentration and FXN expression. Transfection of Ctrl islets with siRNA FXN caused reduction of FXN expression, increase of nitrotyrosine concentration, and reduction of insulin release. In conclusion, in human pancreatic islets FXN contributes to regulation of oxidative stress and insulin release in response to glucose. In islets from T2DM patients FXN expression is reduced while oxidative stress is increased and insulin release in response to glucose impaired.
authors.affiliation: Department of Endocrinology and Metabolism, Section of Metabolic Diseases and Diabetes, Pisa University Hospital, Pisa, Italy.
authors.forename: S
authors.initials: S
authors.lastname: Del Guerra
authors.forename: V
authors.initials: V
authors.lastname: D'Aleo
authors.forename: G
authors.initials: G
authors.lastname: Gualtierotti
authors.forename: R
authors.initials: R
authors.lastname: Pandolfi
authors.forename: U
authors.initials: U
authors.lastname: Boggi
authors.forename: F
authors.initials: F
authors.lastname: Vistoli
authors.forename: S
authors.initials: S
authors.lastname: Barnini
authors.forename: F
authors.initials: F
authors.lastname: Filipponi
authors.forename: S
authors.initials: S
authors.lastname: Del Prato
authors.forename: R
authors.initials: R
authors.lastname: Lupi
mesh_terms: D003924:Diabetes Mellitus, Type 2 / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D005260:Female; D005786:Gene Expression Regulation; D006801:Humans; D033862:Iron-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D007515:Islets of Langerhans / Q000378:metabolism* / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D034741:RNA, Small Interfering / Q000378:metabolism; D012044:Regression Analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014019:Tissue Donors; D014443:Tyrosine / Q000031:analogs & derivatives; D000096923:Frataxin
chemical_list: D033862:Iron-Binding Proteins; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D014443:Tyrosine; D000096923:Frataxin; C002744:3-nitrotyrosine