A new subset of small stem cells in bovine bone marrow stromal cell populations.

Bone marrow stromal cells (BMSCs) are a unique population of multipotent cells that exhibit pluripotent properties to a certain extent and are significantly heterogeneous in terms of the cell population. We isolate a small cell subpopulation from bovine BMSCs, bovine small stem cells (bSSCs), and herein characterize their properties. The bSSCs are smaller in size and express nuclear Oct-4 and other pluripotency markers. In addition, when cultured in suspension conditions, bSSCs form three-dimensional spheres and display a strong capability for self-renewal and differentiation into cells from three germ layers. Notably, bSSCs display neural features with Sox1 and Pax6 expression. Using bSSCs as donor nuclear cells for somatic cell nuclear transfer, we further demonstrate that the developmental potential of cloned embryos in vitro is significantly increased. Our study identifies a new bovine bone marrow stromal cell-derived stem cell subtype that could have broad importance for developmental biology as well as great potential for regenerative medicine.