Erythropoiesis; Proteins/metabolism; Antioxidants/pharmacology; Apoptosis; Bone Marrow Diseases/drug therapy; Bone Marrow Diseases/metabolism; Cell Proliferation; Cells, Cultured; Colony-Forming Units Assay; Erythroid Precursor Cells/cytology; Erythroid Precursor Cells/drug effects; Erythroid Precursor Cells/metabolism; Exocrine Pancreatic Insufficiency/drug therapy; Exocrine Pancreatic Insufficiency/metabolism; Gene Expression Regulation; Gene Knockdown Techniques; Hematopoietic Stem Cells/cytology; Hematopoietic Stem Cells/drug effects; Hematopoietic Stem Cells/metabolism; Humans; K562 Cells; Leucine/metabolism; Lipomatosis/drug therapy; Lipomatosis/metabolism; Oxidative Stress; Protein Biosynthesis; Proteins/antagonists & inhibitors; Proteins/genetics; RNA, Messenger/metabolism; RNA, Small Interfering; Reactive Oxygen Species/metabolism; Recombinant Proteins/antagonists & inhibitors; Recombinant Proteins/metabolism; Ribosomes/metabolism; Shwachman-Diamond Syndrome