title: Heat shock protein-containing exosomes in mid-trimester amniotic fluids.
abstract: 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.
authors: Department of Pathology and Scott & White Hospital and Clinic, Texas A&M Health Science Center, College of Medicine, Texas, USA.
authors: Alexzander
authors: A
authors: Asea
authors: Claudel
authors: C
authors: Jean-Pierre
authors: Punit
authors: P
authors: Kaur
authors: Preethi
authors: P
authors: Rao
authors: Iara M
authors: IM
authors: Linhares
authors: Daniel
authors: D
authors: Skupski
authors: Steven S
authors: SS
authors: Witkin
mesh_terms: 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
chemical_list: D006360:Heat-Shock Proteins