Even though the second season of The Jersey Shore takes place in Miami, the cast remain true to their ‘guido’ roots. I guess sometimes you just can’t change who you really are. The same is true for microRNA expression profiles of iPS cells. A recent review (Lakshmipathy et.al. 2010) from Ron Hart’s group at the Rutgers Stem Cell Research Center, describes intrinsic differences in the microRNA profiles of iPS and hESCs. They make a strong case that although iPS cells express pluripotency markers and behave very similar to hESCs, there are still key transcriptional differences between the two.
Previously, Hart’s group deep sequenced small RNAs from hESCs and iPS cells. This review compares their results to two different reports (Chin et al., 2009 and Wilson et al., 2009) and shows that miRNA expression patterns predict that iPS cells aren’t quite as ‘undifferentiated’ as hESCs.
- While most microRNAs are similarly expressed in hESC and iPS, specific sets of microRNAs distinguish the two cultures
- Specific sets of microRNAs, including the miR-371 family, distinguish hESC from iPS, consistent with a status for iPS that is intermediate between ESC and differentiated cells.
These remnants of differentiation after reprogramming might hinder the capacity of iPS cells to differentiate into multiple tissue types. Will it be possible to completely reprogram iPS cells to a hESC state? Who knows, but we bet it’ll be easier to do than getting the gang on Jersey Shore to lay off the tanning beds.
Get your iPS knowledge up-to-date at Regenerative Medicine, July 2010.