MicroRNA regulation of embryonic lung mesenchyme proliferation and differentiation

MicroRNAs (miRNAs) are small non-coding RNAs that regulate gene expression by binding to their target mRNAs. Mice with ablation of Dicer in the lung epithelium show abnormal lung branching and growth indicating a critical role of the miRNAs machinery during lung morphogenesis. We have investigated miRNAs expression in the embryonic lung and identified miRNAs specifically enriched in the epithelium versus mesenchyme. The role of specific miRNAs was analyzed with embryonic lung organ cultures by loss of function of specific miRNAs using morpholinos. We have specifically screened for miRNAs that contribute to the regulation of FGF and WNT signaling in the embryonic mesenchyme. Modulation of the branching, and effects on cell proliferation and differentiation were used as a readout.