Heat shock protein-containing exosomes in mid-trimester amniotic fluids.
Exosomes are multivesicular bodies formed by inverse membrane budding into the lumen of an endocytic compartment. Fusion with the plasma membrane leads to their release into the external milieu. The incorporation of heat shock proteins into exosomes has been associated with immune regulatory activity. We have examined whether heat shock protein-containing exosomes are present in mid-trimester amniotic fluid. Exosomes were isolated from mid-trimester amniotic fluids by sequential low-speed and high-speed centrifugation followed by sucrose density gradient centrifugation. Biochemical characterization included floatation pattern in sucrose gradients, acetylcholinesterase (AChE) activity and Western blot analysis for exosome-containing proteins. Exosomes were present in each of 23 amniotic fluids tested. They banded at a density of 1.17g/ml in sucrose gradients, were positive for AChE activity and contained tubulin, the inducible 72kDa heat shock protein, Hsp72 and the constitutively expressed heat shock protein, Hsc73; they were negative for calnexin. Exosome concentrations correlated positively with the number of pregnancies. Heat shock protein-containing exosomes are constituents of mid-trimester amniotic fluids and may contribute to immune regulation within the amniotic cavity.
Asea
Alexzander
A
Department of Pathology and Scott & White Hospital and Clinic, Texas A&M Health Science Center, College of Medicine, Texas, USA.
Jean-Pierre
Claudel
C
Kaur
Punit
P
Rao
Preethi
P
Linhares
Iara M
IM
Skupski
Daniel
D
Witkin
Steven S
SS
D000653:Amniotic Fluid / Q000737:chemistry* / Q000166:cytology / Q000276:immunology; D055354:Exosomes / Q000737:chemistry*; D005260:Female; D006360:Heat-Shock Proteins / Q000032:analysis; D006801:Humans; D011247:Pregnancy; D011262:Pregnancy Trimester, Second
D006360:Heat-Shock Proteins