Detection and Quantitation of Circulating Human Irisin by Tandem Mass Spectrometry.
Exercise provides many health benefits, including improved metabolism, cardiovascular health, and cognition. We have shown previously that FNDC5, a type I transmembrane protein, and its circulating form, irisin, convey some of these benefits in mice. However, recent reports questioned the existence of circulating human irisin both because human FNDC5 has a non-canonical ATA translation start and because of claims that many human irisin antibodies used in commercial ELISA kits lack required specificity. In this paper we have identified and quantitated human irisin in plasma using mass spectrometry with control peptides enriched with heavy stable isotopes as internal standards. This precise state-of-the-art method shows that human irisin is mainly translated from its non-canonical start codon and circulates at ∼ 3.6 ng/ml in sedentary individuals; this level is increased to ∼ 4.3 ng/ml in individuals undergoing aerobic interval training. These data unequivocally demonstrate that human irisin exists, circulates, and is regulated by exercise.
Dana-Farber Cancer Institute and Department of Cell Biology, Harvard Medical School, 44 Binney Street, Boston, MA 02115, USA.|Department of Cell Biology, Harvard Medical School, 240 Longwood Avenue Boston, MA 02115.
Mark P
MP
Jedrychowski
Dana-Farber Cancer Institute and Department of Cell Biology, Harvard Medical School, 44 Binney Street, Boston, MA 02115, USA.
Christiane D
CD
Wrann
Department of Cell Biology, Harvard Medical School, 240 Longwood Avenue Boston, MA 02115.
Joao A
JA
Paulo
Dana-Farber Cancer Institute and Department of Cell Biology, Harvard Medical School, 44 Binney Street, Boston, MA 02115, USA.
Kaitlyn K
KK
Gerber
Department of Cell Biology, Harvard Medical School, 240 Longwood Avenue Boston, MA 02115.
John
J
Szpyt
Division of Endocrinology, 200 First Street SW, Joseph 5-193, Mayo Clinic, Rochester, MN 55905.
Matthew M
MM
Robinson
Division of Endocrinology, 200 First Street SW, Joseph 5-193, Mayo Clinic, Rochester, MN 55905.
K Sreekumaran
KS
Nair
Department of Cell Biology, Harvard Medical School, 240 Longwood Avenue Boston, MA 02115.
Steven P
SP
Gygi
Dana-Farber Cancer Institute and Department of Cell Biology, Harvard Medical School, 44 Binney Street, Boston, MA 02115, USA.
Bruce M
BM
Spiegelman
D000328:Adult; D000595:Amino Acid Sequence; D015992:Body Mass Index; D002851:Chromatography, High Pressure Liquid; D004591:Electrophoresis, Polyacrylamide Gel; D015444:Exercise; D005353:Fibronectins / Q000097:blood* / Q000378:metabolism; D006801:Humans; D007553:Isotope Labeling; D008297:Male; D008969:Molecular Sequence Data; D010455:Peptides / Q000032:analysis; D053719:Tandem Mass Spectrometry; D055815:Young Adult
C577593:FNDC5 protein, human; D005353:Fibronectins; D010455:Peptides