Open AccessLaminin isoforms in human embryonic stem cells: synthesis, receptor usage and growth support
Author(s) -
Vuoristo Sanna,
Virtanen Ismo,
Takkunen Minna,
Palgi Jaan,
Kikkawa Yamato,
Rousselle Patricia,
Sekiguchi Kiyotoshi,
Tuuri Timo,
Otonkoski Timo
Publication year - 2009
Publication title -
journal of cellular and molecular medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.44
H-Index - 130
eISSN - 1582-4934
pISSN - 1582-1838
DOI - 10.1111/j.1582-4934.2008.00643.x
Subject(s) - matrigel , microbiology and biotechnology , embryonic stem cell , laminin , biology , cell adhesion , integrin , stem cell , induced pluripotent stem cell , adhesion , cell culture , receptor , extracellular matrix , cell , chemistry , biochemistry , genetics , gene , organic chemistry
To reveal the functional intrinsic niche of human embryonic stem cells (hESC) we examined the production of basement membrane (BM) proteins and the presence of their receptors in feeder‐free cell culture conditions. In addition, we investigated binding of hESCs to purified human BM proteins and identified the receptors mediating these contacts. Also, we tested whether purified human laminin (Lm) isoforms have a role in hESC self‐renewal and growth in short‐term cultures. The results show that hESCs synthesize Lm α 1 and Lm α 5 chains together with Lm β 1 and γ 1 chains suggesting the production of Lms‐111 and ‐511 into the culture medium and deposits on cells. hESCs contain functionally important integrin (Int) subunits, Int β 1 , α 3 , α 6 , α 5 , β 5 and α V , as well as the Lm α 5 receptor, Lutheran (Lu) glycoprotein and its truncated form, basal cell adhesion molecule (B‐CAM). In cell adhesion experiments, Int β 1 was crucial for adhesion to most of the purified human BM proteins. Lu/B‐CAM mediated adhesion to Lm‐511 together with Int α 3 β 1 , and was essential for the adhesion of hESCs to embryonic feeder cells. Adhesion to Lm‐411 was mediated by Int α 6 β 1 . Lm‐511 supported hESC growth in defined medium equally well as Matrigel. These results provide consequential information of the biological role of BM in hESCs, warranting further investigation of BM biology of human pluripotent stem cells.