Smad-Interacting Protein-1 and MicroRNA 200 Family Define a Nitric Oxide–Dependent Molecular Circuitry Involved in Embryonic Stem Cell Mesendoderm Differentiation
Objective—Smad-interacting protein-1 (Sip1/ZEB2) is a transcriptional repressor of the human catalytic telomerase subunit (Tert) and has recently been identified as a key regulator of embryonic cell fate with a phenotypic effect similar, in our opinion, to that reported for nitric oxide (NO). Remarkably, SIP1/ZEB2 is a known target of the microRNA 200 (miR-200) family. In this light, we postulated that Sip1/ZEB2 and the miR-200 family could play a role during the NO-dependent differentiation of mES.
Methods and Results—The results of the present study show that Sip1/ZEB2 expression is downregulated during the NO-dependent expression of mesendoderm and early cardiovascular precursor markers, including Flk1 and CXCR4 in mES. Coincidently, members of the miR-200 family, namely miR-429, -200a, -200b, and -200c, were transcriptionally induced in parallel to mouse Tert. This regulation occurred at the level of chromatin. Remarkably, miR-429/miR-200a overexpression or Sip1/ZEB2 knockdown by short hairpin RNA interference elicited a gene expression pattern similar to that of NO regardless of the presence of leukemia inhibitory factor.
Conclusion—These results are the first demonstrating that the miR-200 family and Sip1/ZEB2 transcription factor are regulated by NO, indicating an unprecedented molecular circuitry important for telomerase regulation and early differentiation of mES.
- biology, developmental
- gene expression
- molecular biology
- nitric oxide
- vascular biology
- Received August 12, 2010.
- Accepted December 22, 2010.
- © 2011 American Heart Association, Inc.