Modeling primitive and definitive erythropoiesis with induced pluripotent stem cells

Area of Science:

• Hematology
• Stem Cell Biology
• Developmental Biology

Background:

• Erythroid cells develop via primitive and definitive hematopoietic waves with distinct characteristics.
• Human induced pluripotent stem cells (iPSCs) offer a model for studying red blood cell (RBC) development, particularly post-primitive hematopoiesis.
• Generating definitive hematopoietic progenitors from iPSCs allows for direct comparison with primitive RBCs from isogenic sources.

Purpose of the Study:

• To compare primitive and definitive erythrocytes derived from iPSCs and fetal liver cells.
• To investigate functional and transcriptomic differences between primitive and definitive RBCs.
• To assess the utility of iPSCs for modeling genetic hematologic diseases and developing transfusion products.

Main Methods:

• Generated isogenic primitive and definitive RBCs from iPSCs derived from fetal liver cells.
• Performed functional assays to compare RBC characteristics.
• Utilized single-cell RNA sequencing (scRNA-seq) for transcriptome profiling.
• Introduced a pathogenic mutation in KLF1 in iPSC lines to study disease-specific changes.

Main Results:

• Primitive RBCs exhibited reduced proliferation, larger size, no Duffy antigen expression, and higher embryonic globin expression compared to definitive RBCs.
• scRNA-seq revealed high similarity between fetal liver- and iPSC-derived definitive RBCs, with distinct gene expression patterns for primitive RBCs.
• iPSC lines with a KLF1 mutation showed definitive RBC-specific phenotypic changes.

Conclusions:

• This study provides novel insights into the differences between primitive and definitive erythropoiesis.
• Highlights the importance of considering hematopoietic ontology when using iPSCs for disease modeling.
• The similarity between fetal liver- and iPSC-derived definitive RBCs supports their potential for diagnostic and transfusion applications.