Supplementary Material for: Hampered Lung Maturation in Methimazole-Induced Hypothyroidism in Fetal Chicken: Morphological and Molecular Correlates to Human Fetal Development

<br><strong><em>Background:</em></strong> Molecular understanding of lung development is crucial for developing therapies and diagnostic tools. Animal models with altered thyroid hormone signaling provide mechanistic insight into thyroid-dependent neonatal lung disease. Repression of Klf2 (Krüppel-like factor 2), a suggested T3 target gene, is associated with disrupted lung development in mice. Klf2 is proposed to be specifically involved in type I pneumocyte differentiation. <b><i>Objectives:</i></b> To explore mechanisms of thyroid-dependent lung disease, we studied developing chicken fetuses with experimentally induced hypothyroidism. <b><i>Methods:</i></b> Morphology and the expression of a panel of molecules linked to Klf2 were assessed using histology, immunohistochemistry, Western blot and qPCR. <b><i>Results:</i></b> Methimazole injections at E14 hampered lung maturation. The effects of methimazole were evident in several tissue compartments, and impacted on both pneumocyte and vascular differentiation, suggesting cellular and molecular pleiotropy. <b><i>Conclusions:</i></b> Concomitant expression changes in a panel of selected microRNAs regulated by Klf2 suggest importance in lung development. These microRNAs may thus represent potential clinical targets and diagnostic and prognostic tools in thyroid-dependent lung disease.