Microvesicle-mediated release of soluble LH/hCG receptor (LHCGR) from transfected cells and placenta explants

• Published in: Reproductive biology and endocrinology 2011-05, Vol.9 (1), p.64-64, Article 64
• Main Authors: Chambers, Anne E, Stanley, Paul F, Randeva, Harpal, Banerjee, Subhasis
• Format: Article
• Language: English
• Subjects: Animals; Cells, Cultured; CHO Cells; Cricetinae; Cricetulus; Female; Gonadotropin releasing hormone; Humans; Organ Culture Techniques; Physiological aspects; Placenta; Placenta - metabolism; Placenta - secretion; Pregnancy; Receptors, LH - genetics; Receptors, LH - metabolism; Recombinant proteins; Secretory Vesicles - metabolism; Solubility; Transfection
• ISSN: 1477-7827; 1477-7827
• DOI: 10.1186/1477-7827-9-64

Placental hCG and pitutary LH transduce signals in target tissues through a common receptor (LHCGR). We demonstrate that recombinant LHCGR proteins which include the hormone-binding domain are secreted from transfected cells and that natural LHCGR is also secreted from human placental explants. LHCGR recombinant proteins representing varying lengths of the N-terminal extracellular domain were expressed in Chinese Hamster Ovary cells in suspension culture. Secretion was minimal up to 72h but by 96h 24-37% of the LHCGR had been released into the culture medium. The secreted proteins were folded and sensitive to glycosidases suggesting N-linked glycosylation. Secretion was independent of recombinant size and was mediated via structurally defined membrane vesicles (50-150nm). Similarly cultured human early pregnancy placental explants also released LHCGR via microvesicles. These studies provide the first experimental evidence of the possible mechanistic basis of the secretion of LHCGR.