Ex vivo mouse hematopoietic stem cell expansion using polyvinyl alcohol

The self-renewal of multipotent hematopoietic stem cells (HSCs) is key for life-long maintenance of hematopoiesis and the curative capacity of clinical bone marrow transplantation. However, while in vivo HSC self-renewal has been well-described, existing culture conditions poorly support ex vivo HSC self-renewal and afford a very limited window to study or modify HSCs in-a-dish. Here, we describe a simple culture platform that supports functional mouse HSCs ex vivo for 1-2 months. Rather than containing serum albumin, the media uses the synthetic polymer polyvinyl alcohol (PVA). PVA represents an inexpensive and chemically-defined alternative to serum albumin supplements, which have long represented a major source of biological contaminants and batch-to-batch variability in HSC cultures. This novel culture system therefore provides a useful platform to expand and interrogate mouse HSCs.