Elucidating the Effect of Protein Phosphatase 2A Inhibitors in Branching Morphogenesis of the Embryonic Chicken Lung

Abstract

The embryonic chicken lung develops through a stereotyped process of branching morphogenesis that is driven by apical constriction. Secondary bronchi form from contracting actomyosin contraction, which causes epithelial cells to form into a wedge-shaped geometry. Protein phosphatase 2A (PP2A) affects the development and differentiation of mammalian lungs by mechanochemical signaling in epithelial cells; however, it is unclear whether PP2A plays a role in apical constriction during the development of the avian lung. To better understand the role of PP2A in avian lung branching morphogenesis, I inhibited its enzymatic activity using okadaic acid (OKA), or calyculin A (Caly A). Specifically, I treated embryonic chicken lungs with these inhibitors to determine the effects on secondary branching. I used immunofluorescent staining to examine the effects of inhibiting PP2A on cell proliferation and the actin cytoskeleton. My data suggests that treatment with PP2A hinders both secondary branch initiation and elongation. Immunofluorescent imagining showed inhibiting PP2A had no effect on cell proliferation or F-actin accumulation. Both inhibitors had similar results– indicating repeatable physiological outcomes when using different PP2A inhibitors.