Research on stem cells: Ideas, questions, data gathering Brenda Russell PhD Physiology, Bioengineering, Medicine UIC 22 Feb, 2008 ©

BIG QUESTION ? How is life evolved to adapt to physical forces? Idea = guess= hypothesis Based on work done by others and new unexpected observations Scientific method Tests to see if guesses are correct or not ©

Hypothesis = ? Strong attachment of cells to surroundings affects their function Test Alter surroundings with bioengineering and observe cells ©

Stem cell differentiation and maturation Chemical : growth factors, genes, drugs, cell signaling Physical : forces, topography, scaffolds stem final Cell source

Cell soon after plating in culture Focal adhesions Crawling

Micro Soccer reactive forces immobile sphere mobile sphere reactive forces ©

flat 10  m high fibroblast # x 1000 Day Flat Micropeg Fibroblasts on 2D flat or 3D niche membranes Boateng, SY, TJ Hartman, N Ahluwalia, H Vidula, TA. Desai and B. Russell. Am J. Physiol: Cell. 285:C171-C182, 2003 ©

Net force is zero Cells can do physics Newton’s Third Law of Physics Every force has an equal and opposite reactive force. N ©

Hypothesis Stem cell niche of microenvironment affects function ©

How many cell divisions before cells specialize? One division = 2 cells Two divisions = 4 cells Three divisions = 8 cells ©

Four divisions = 16 cells One cell is now in the middle Rest have inner and outer surfaces Physical Niche

Engler AJ, Sen S, Sweeney HL, Discher DE. Matrix elasticity directs stem cell lineage specification. Cell Aug 25;126(4): brain muscle bone

Hypothesis Stem cells respond to the physical cues Experiment to test Alter niche by microtopography and measure cell response

PP PP  Projection  cardiac myocyte  non Myocyte Microtopography: mouse cardiac stem cells Disclosure: Microtextured surfaces will be manufactured by Cell Habitats, LLC US Patent: Russell and Desai ©

Cell division on flat surfaces Dividing Green- BrDU+ ALL: Red- PI ©

Cell division blunted by 80µm projections Dividing Green- BrDU+ ©

* * * p<0.05 (4 days) Mouse embryonic stem cell proliferation Projection Spacing (n=4) Ratio of Flat 80um 500um ©

Mouse embryonic stem cells division is blunted by 80um projections nearfar Distance from Projection Ratio dividing ©

Beating cells derived from mouse embryonic stem cells Flat surface ©

Beating cells grown on microprojections ©

Conclusion Microtopgraphy blunts proliferation of stem cells Beating rates of derived heart cells vary greatly when plated on microprojections

Science new ideas questions test with latest techniques measurments Leads to next guess and next ?

Acknowledgements Funding from NIH and Illinois regenerative medicine Russell Lab UIC Sam Boateng PhD Delara Motlagh PhD Haytham Mansour PhD Yevgeniya Koshman PhD Sam Senyo Jesse Biehl John Collins Tejal Desai, Ph.D. Bioengineering, UCSF Allen Samarel MD Loyola, Maywood, IL