GDNF-expressing STO Feeder Layer Supports Long-term Propagation Of Mouse Spermatogonial Stem Cells

Development of stem cell culture system will expediate our understanding of the biology for tissue regeneration.Spermatogonial stem cell(SSC)is the foundation for life-long male spermatogenesis and the culture of SSCs has been optimized continuously in recent years,but there were still some inconveniences to reconstruct SSC self-renewal and proliferation in vitro,including frequent refreshment of multiple recombinant growth factors into culture.GDNF is the essential growth factor for SSC maintenance,however,we found that STO and MEF cells,both previously used as feeders for SSC growth,did not express GDNF.However,a GDNF-expressing STO feeder could support mouse SSC propagation in vitro for over three months without refreshment of recombinant growth factor GDNF.The cell morphology,growth rate and SSC-associated gene expression remained identical to those SSCs cultured using previous methods.Transplantation of SSCs growing on GDNF-expressing STO feeder could generate extensive colonies of spermatogenesis in recipient testis,functionally validating sternness of these cells.Collectively,our data indicated that further modification of feeder cells might facilitate self-renewal and propagation of SSCs in vitro.