Myostatin is a human placental product that regulates glucose uptake.
BACKGROUND
Myostatin is a member of the TGF-beta superfamily and is primarily known for its ability to inhibit muscle growth. It also has actions on glucose metabolism. We hypothesized that it may act as a paracrine regulator of glucose uptake in the placenta, potentially contributing to fetal and placental growth.


OBJECTIVE
The objective of this study was to determine whether myostatin is present in and formed by the human placenta and to evaluate its effects on glucose uptake.


METHODS
Myostatin protein and mRNA were measured using Western immunoblotting and real-time PCR, respectively. Glucose uptake was assessed by uptake of radiolabeled deoxyglucose in vitro. Placental tissues were obtained at term (n = 8), preterm (n = 8; 24-34 wk), and early in pregnancy (n = 6; 9-13 wk).


RESULTS
Human placentas were shown to express myostatin protein, with a significantly lower expression in term samples compared with samples collected in preterm samples. Human placentas express myostatin mRNA throughout gestation, which does not change. Myostatin treatment of human term placental explants resulted in an increase in deoxyglucose uptake compared with controls.


CONCLUSIONS
Myostatin is synthesized, released, and acts within the human placenta. It contributes to placental glucose homeostasis and may be a therapeutic target in diseases ranging from placental insufficiency to diabetes in pregnancy.
Mitchell
Murray D
MD
Liggins Institute, University of Auckland, Private Bag 92019, Auckland 1003, New Zealand. m.mitchell@auckland.ac.nz
Osepchook
Claire C
CC
Leung
Kai-Cheung
KC
McMahon
Christopher D
CD
Bass
John J
JJ
D000328:Adult; D015153:Blotting, Western; D003847:Deoxyglucose / Q000378:metabolism; D005260:Female; D005947:Glucose / Q000378:metabolism*; D006801:Humans; D055435:Myostatin; D019899:Paracrine Communication / Q000502:physiology; D010920:Placenta / Q000378:metabolism*; D011247:Pregnancy; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016212:Transforming Growth Factor beta / Q000502:physiology*
C525911:MSTN protein, human; D055435:Myostatin; D012333:RNA, Messenger; D016212:Transforming Growth Factor beta; D003847:Deoxyglucose; D005947:Glucose