ASS1 and idiopathic pulmonary fibrosis: As expected, we found that IPF fibroblasts with ASS1 deficiency display downregulated inositol level and upregulated expression of several enzymes (i.e., MIOX and CDIPT) involved in inositol catabolism and phosphatidylinositol metabolism, suggesting that ASS1-deficient lung fibroblasts tend to consume and/or eliminate most of cellular inositol.