Expansion of therapeutic stem cells

Sponsored by: Invitria
Session ends: January 25th, 2014, 3:00pm MST
Answers by: Randall Alfano, Cell Culture Scientist, Invitria


The full realization of the therapeutic potential of stem cells has only recently come into the forefront of regenerative medicine. Promising in vivo results have fueled the enthusiasm among basic researchers and their clinical colleagues and thus have widened the scope of stem cell application in human disease but major scientific and regulatory challenges exist and must be addressed in order to both facilitate the “bench to bedside” process of this nascent technology as well as enhance safety of the final cell product. One potential key to advancing stem cell therapies is described in the recent blog “Planting the seed: plant-based biologics for the expansion of therapeutic stem cells.” The blog discusses how human LIF protein (rhLIF) was expressed in rice grain using a plant-based expression platform (ExpressTec) and demonstrated a 97% purity of the protein. The rhLIF was then used in stem cells to promote cell proliferation and maintenance of the pluripotent state. Please submit your questions about the information in the blog, LIF itself, the application of LIF, or animal component-free stem cell media.

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Questions & Answers

Can you explain the different applications for mouse vs. human vs. recombinant human LIF. When would I need to use each?

Traditionally LIF has been supplied to ESCs by secretion directly into the culture media by mitotically-inactivated mouse embryonic fibroblasts (MEFs). However, feeder layers have limitations. Not only are they very labor intensive to prepare, but problems also arise with isolating stem cells due to inefficient separation of the two cell types. Further, variations between MEF […]» Read More

Can you explain more about LIF’s role in stem cell culture its importance?

LIF is a member of the IL-6 cytokine family. It has been identified as a key regulator in the maintenance of stem cell pluripotency. LIF binds to a receptor complex that activates gp130/STAT3-dependent signaling, leading to increased transcription of the stem cell state regulators while simultaneously inhibiting differentiation. See Burdon et al,. Trends in Cell […]» Read More

Can you explain how you extract the LIF from the rice.

Although the exact extraction conditions for the rhLIF is proprietary, the link http://www.ventria.com/about-us/our-technology explains the entire expression and purification process. Typically with any ExpressTec-derived protein, a simple aqueous extraction is sufficient to remove the protein from the rice grain for subsequent chromatography.» Read More