Engineered humanized bone organs maintain human hematopoiesis in vivo

Area of Science:

• Stem cell biology
• Tissue engineering
• Hematopoiesis

Background:

• Hematopoietic stem cells (HSCs) rely on the bone marrow (BM) niche for maintenance.
• Human BM HSC niche components are less understood compared to mouse models.
• Mesenchymal stromal cells (MSCs) can be engineered to form bone organs (ossicles).

Purpose of the Study:

• To investigate if human MSC-derived ossicles can support human hematopoiesis in vivo.
• To compare the maintenance of human hematopoietic stem and progenitor cells in ossicles versus mouse BM.
• To explore the potential of engineered ossicles as a platform for studying human hematopoiesis.

Main Methods:

• Developmental tissue engineering approach using human adult BM-derived MSCs.
• In vivo implantation of engineered human ossicles into immunodeficient mice.
• Analysis of human hematopoiesis, including stem and progenitor cell populations and quiescence levels.

Main Results:

• Human ossicles successfully supported both immature and mature human hematopoiesis in vivo.
• A higher percentage of human stem and progenitor cells remained quiescent in human ossicles compared to mouse BM.
• Human MSC-derived ossicles demonstrated functionality as a hematopoietic niche.

Conclusions:

• Human ossicles engineered from MSCs serve as a functional hematopoietic niche.
• These ossicles maintain human hematopoietic stem and progenitor cells in a quiescent state.
• Engineered ossicles offer a promising platform for studying normal and diseased human hematopoiesis.