Multi-potent adult progenitor cells from swine bone marrow

¹ Stem Cell Institute, University of Minnesota, Minneapolis, Minnesota; Department of Biomedical Engineering, University of Minnesota, Minneapolis, Minnesota
² Stem Cell Institute, University of Minnesota, Minneapolis, Minnesota
³ Department of Medicine, Medical School, University of Minnesota, Minneapolis, Minnesota
⁴ Veterinary Population Medicine Department, University of Minnesota, Minneapolis, Minnesota
⁵ Department of Medicine, Medical School, University of Minnesota, Minneapolis, Minnesota; Department of Biomedical Engineering, University of Minnesota, Minneapolis, Minnesota
⁶ Stem Cell Institute, University of Minnesota, Minneapolis, Minnesota; Department of Medicine, Medical School, University of Minnesota, Minneapolis, Minnesota

^* To whom correspondence should be addressed. E-mail: verfa001{at}umn.edu.

	Abstract

We show that Multi-potent Adult Progenitor Cells (MAPCs) can be derived from both postnatal and fetal swine bone marrow (BM). Although swine (sw)MAPC cultures are initially mixed, cultures are phenotypically homogenous by 50 population doublings (PDs) and can be maintained as such for more than 100 PDs. swMAPCs are CD44, CD45, and MHC-Class I and II negative, express octamer binding transcription factor 3a (Oct3a) mRNA and protein at levels close to those seen in human embryonic stem cells (hESCs), and have telomerase activity preventing telomere shortening even after 100 PDs. Using Q-RT-PCR, Immunofluorescence and functional assays, we demonstrate that swMAPCs differentiate into chondrocytes, adipocytes, osteoblasts, smooth muscle cells, endothelium, hepatocyte-like cells and neuron-like cells. Consistent with what we have shown for human and rodent MAPCs, Q-RT-PCR, demonstrated a significant upregulation of transcription factors and other lineage specific transcripts in a time dependent fashion similar to development. When swMAPCs were passaged for 3-6 passages at high density (2,000-8,000 cells/cm²), Oct3a mRNA levels were no longer detectable, cells acquired the phenotype of mesenchymal stem cells (CD44+, MHC-Class I+), and could only differentiate into typical mesenchymal lineages (adipocytes, osteoblasts and chondroblasts), but not endothelium, hepatocyte- and neuron-like cells. Even if cultures were subsequently replated at low density (100500 cells/cm²) for >20 PDs, Oct3a was not re-expressed, nor were cells capable of differentiating to cells other than mesenchymal type cells. This suggests that the phenotype and functional characteristics of swMAPCs may not be an in vitro culture phenomenon.