Reprogramming human B cells into induced pluripotent stem cells and its enhancement by C/EBPα.

Area of Science:

• Stem Cell Biology
• Immunology
• Genetics

Background:

• B cells are typically refractory to cellular reprogramming.
• Previous methods for generating B-cell-derived induced pluripotent stem cells (iPSCs) required genetic engineering or immortalized cell lines.

Purpose of the Study:

• To investigate the direct reprogramming of freshly isolated human B cells into iPSCs.
• To determine the efficiency of non-integrative Sendai virus vectors for B-cell reprogramming.
• To assess the differentiation potential of resulting iPSCs and explore the role of epigenetic memory.

Main Methods:

• Reprogramming of freshly isolated human cord blood (CB) and peripheral blood (PB) CD19+CD20+ B cells using non-integrative tetracistronic Sendai virus vectors expressing Oct4, Sox2, Klf4, and Myc (OSKM).
• Evaluation of co-expression with C/EBPα to enhance reprogramming efficiency.
• Comparison of reprogramming efficiency between B cells, T lymphocytes, and myeloid cells.
• Assessment of differentiation potential of generated iPSCs back into their cell of origin.

Main Results:

• Successfully generated iPSCs from non-cultured human CB- and PB-derived B cells, retaining complete VDJH immunoglobulin gene rearrangements.
• Non-integrative tetracistronic, but not monocistronic, OSKM-expressing Sendai virus enabled reprogramming.
• Co-expression of C/EBPα significantly facilitated iPSC generation from B cells.
• Myeloid cells showed higher reprogramming efficiency compared to B and T lymphocytes.
• Generated iPSCs (B-cell, T-cell, myeloid, fibroblast) exhibited unbiased differentiation potential, suggesting no significant 'epigenetic memory' influence.

Conclusions:

• Freshly isolated human primary B cells can be directly reprogrammed into iPSCs using specific Sendai virus vectors.
• This method overcomes previous limitations and allows for the study of cell-autonomous reprogramming capacity.
• The ability to generate B-cell-derived iPSCs provides a powerful tool for studying B lymphopoiesis and modeling B-cell malignancies.