Reactivation of miR-203 expression is required for neural crest coalescence to form trigeminal ganglion

SÁNCHEZ-VÁSQUEZ, ESTEFANÍA; STROBL MAZZULLA, P.H.; BERNARDI, YANEL

Buenos Aires

Simposio; Latin american society of developmental biology; 2019

Neural crest (NC) is a transient pluripotent group ofcells that emigrate from the dorsal neural tube, via epithelial-mesenchymaltransition (EMT), to contribute to numerous derivatives in vertebrates. Ourgroup have recently demonstrated that the epigenetic repression of miR-203 isrequired to initiate the EMT. In a manner that is essentially the reverse of thisinitial transition, the formation of sensory ganglia requires the coalescenceof NC. In this context, we hypothesized that a dynamic and reversibleepigenetic mechanisms may be involved on the regulation of miR-203 expression duringthe trigeminal ganglion (TG) formation. Expression analysis by in situ hybridization reveals that miR-203is not detected in migratory NC, but it is re-expressed on the coalescent cellsof the TG. This dynamic expression is in agreement with the reduced percentageof CpG methylation detected in migratory compared with pre-migratory NC. Interestingly,overexpression of miR-203 generates ectopic aggregation of NC as well as a morecondensed TG. In an opposite manner, loss of function of miR-203 results in amore disperse TG assembly. Taking all into account, we conclude thatre-activation of miR-203 expression is key for the NC condensation to form the TG.The complete understanding of this epigenetic-miRNA reversibility during thedelamination and coalescence of NC may have potential implication in theunderstanding of tumor metastasis, specially the establishment of secondarytumors.