SPDEF and acute respiratory distress syndrome: The ERN2/IRE1β sensor is essential for goblet cell differentiation and allows adaptation of the unfolded stress response in the ER to allow for production of MUC2 in goblet cells.33,34 The transcription factors ATOH1 and SPDEF are regulators of intestinal differentiation and goblet cell formation and are responsible for the regulation of a network of genes involved in mucus production.35–37 In our dataset, ATOH1 showed a non-significant trend that indicated upregulation under ALI conditions.