a-5 Laminin Synthesized by Human Pluripotent Stem Cells Promotes Self-Renewal

The authors study the role of endogenously produced extracellular matrix (ECM) components in regulating hPSC fates. They identify a-5 laminin as a signature ECM component endogenously synthesized by undifferentiated hESC and hiPSC cultured on defined substrates. The cells also produced collagen I but no vitronectin or fibronectin. Knockdown and disruption of the LAMA5 gene dramatically reduced hPSC self-renewal and increased apoptosis without affecting the expression of pluripotency markers. Self-renewal and survival were restored to wild-type levels by culturing the LAMA5-deficient cells on exogenous laminin-521. Systemax or Vitronectin could not restore survival. Treatment of LAMA5-deficient cells with blebbistatin or a ROCK inhibitor partially restored self-renewal and diminished apoptosis. These results demonstrate that endogenous a-5 laminin promotes hPSC survival and self-renewal in an autocrine and paracrine manner. A good publication that also shows how much better laminin-521 performs compared to other competitor matrices.