Understanding the impact of targeting the epigenetic regulation of lung stem cells in congenital lung disease

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Project Summary Congenital lung diseases are serious disorders which prematurely end the lives of many and place large health burdens on surviving individuals throughout their lives. Congenital Diaphragmatic Hernia (CDH) is one such disease which causes severe underdevelopment (hypoplasia) of the lung. Although the hernia can be surgically repaired, the lung defects are persistent, leading to high mortality and complicated long-term care for survivors. There are many genetic factors contributing to CDH, and some of these genes change lung development independently from the effects of the hernia, showing their intrinsic importance to the normal growth of the lung. Through a synthesis of genomic and transcriptomic analyses of CDH patients we have identified two genes, KMT2D and KDM6A as strong candidates to mediate the severe lung hypoplasia. KMT2D (Lysine Methyltransferase 2D) and KDM6A (Lysine Demethylase 6A) are co-operating epigenetic regulators which can be both mutated and downregulated in CDH and are known to be important to stem cells. New technological advances have allowed us to isolate lung epithelial basal stem cells from the tracheal aspirates of recruited CDH and control patients. We will utilize these cells to test if the loss of function of these epigenetic regulators affects the ability of these cells to self-renew and generate differentiated lung epithelium, and to identify the downstream genes which they control. Our specific aims are 1) Determine the effects of pathogenic KMT2D/KDM6A genetic variants and pharmaceutical interventions on the differentiation/self-renewal of patient- derived lung basal stem cells derived from tracheal aspirates, and 2) Map the H3K4me1 and H3K27me3 epigenetic changes in CDH and control basal stem cells following mutation or inhibition of KMT2D/KDM6A. With this approach we will be taking advantage of the genetic breakthroughs in CDH to make discoveries that are potentially relevant to a whole class of lung diseases. These aims will help us understand how the mechanisms governing lung development go awry and enable us to develop therapies to correct these problems.