Injection of Human Bone Marrow and Mononuclear Cell Extract into Infarcted Mouse Hearts Results in Functional Improvement

Background: We have previously shown that mouse whole bone marrow cell (BMC) extract results in improvement of cardiac function and decreases scar size in a mouse model of myocardial infarction (MI), in the absence of intact cells. It is not clear if thes

Mechanisms of blood homeostasis: lineage tracking and a neutral model of cell populations in rhesus macaques

BACKGROUND: How a potentially diverse population of hematopoietic stem cells (HSCs) differentiates and proliferates to supply more than 10(11) mature blood cells every day in humans remains a key biological question. We investigated this process by quantitatively analyzing the clonal structure of peripheral blood that is generated by a population of transplanted lentivirus-marked HSCs in myeloablated rhesus macaques. Each transplanted HSC generates a clonal lineage of cells in the peripheral blood that is then detected and quantified through deep sequencing of the viral vector integration sites (VIS) common within each lineage. This approach allowed us to observe, over a period of 4-12 years, hundreds of distinct clonal lineages. RESULTS: While the distinct clone sizes varied by three orders of magnitude, we found that collectively, they form a steady-state clone size-distribution with a distinctive shape. Steady-state solutions of our model show that the predicted clone size-distribution is sensitive to only two combinations of parameters. By fitting the measured clone size-distributions to our mechanistic model, we estimate both the effective HSC differentiation rate and the number of active HSCs. CONCLUSIONS: Our concise mathematical model shows how slow HSC differentiation followed by fast progenitor growth can be responsible for the observed broad clone size-distribution. Although all cells are assumed to be statistically identical, analogous to a neutral theory for the different clone lineages, our mathematical approach captures the intrinsic variability in the times to HSC differentiation after transplantation. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12915-015-0191-8) contains supplementary material, which is available to authorized users

A self-renewal assay for cancer stem cells

Cancers of epithelial origin are responsible for the majority of cancer-related deaths in the USA. Unfortunately, although chemotherapy and/or radiation therapy can sometimes shrink tumors, metastatic cancers of epithelial origin are essentially incurable. It is clear that new approaches are needed to treat these diseases. Although cancer cell lines provide invaluable information, their biological properties often differ in crucial ways from de novo cancer cells. Our laboratory has developed a novel mouse model that reliably permits individual cancer cells isolated directly from patients’ tumors to be assayed. This will allow the characterization of crucial signaling pathways involved in processes such as self-renewal that are critical for tumor formation by the cancer cells within de novo tumors. These tools should lead to new insights into the cellular and molecular mechanisms that drive human breast cancer growth and invasion.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46932/1/280_2005_Article_97.pd

Further phenotypic characterization of the primitive lineage− CD34+CD38−CD90+CD45RA− hematopoietic stem cell/progenitor cell sub-population isolated from cord blood, mobilized peripheral blood and patients with chronic myelogenous leukemia

The most primitive hematopoietic stem cell (HSC)/progenitor cell (PC) population reported to date is characterized as being Lin−CD34+CD38−CD90+CD45R. We have a long-standing interest in comparing the characteristics of hematopoietic progenitor cell populations enriched from normal subjects and patients with chronic myelogenous leukemia (CML). In order to investigate further purification of HSCs and for potential targetable differences between the very primitive normal and CML stem/PCs, we have phenotypically compared the normal and CML Lin−CD34+CD38−CD90+CD45RA− HSC/PC populations. The additional antigens analyzed were HLA-DR, the receptor tyrosine kinases c-kit and Tie2, the interleukin-3 cytokine receptor, CD33 and the activation antigen CD69, the latter of which was recently reported to be selectively elevated in cell lines expressing the Bcr-Abl tyrosine kinase. Notably, we found a strikingly low percentage of cells from the HSC/PC sub-population isolated from CML patients that were found to express the c-kit receptor (<1%) compared with the percentages of HSC/PCs expressing the c-kitR isolated from umbilical cord blood (50%) and mobilized peripheral blood (10%). Surprisingly, Tie2 receptor expression within the HSC/PC subset was extremely low from both normal and CML samples. Using in vivo transplantation studies, we provide evidence that HLA-DR, c-kitR, Tie2 and IL-3R may not be suitable markers for further partitioning of HSCs from the Lin−CD34+CD38−CD90+CD45RA− sub-population

Primitive hematopoietic stem cell function in vivo is uniquely high in the CXB-12 mouse strain.

Bone marrow cells (BMCs) from CXB-12/HiaJ (CXB-12) mice had 14 times the total long-term repopulating ability found in the best of 11 other CXB recombinant inbred (RI) lines. BMCs from each RI line donor were mixed with genetically marked standard competitor BMCs from the BALB/cByxC57BL/6 F1 (CByB6F1) hybrid, the mice used to produce the RI lines, and the mixtures repopulated lethally irradiated CByB6F1 recipients. Percentages of donor-type erythrocytes and lymphocytes measured the actual long-term repopulating functions of the donor RI lines relative to the standard competitor. CXB-12 BMCs repopulated better after 3 or 6 months than after 1 month, suggesting that the most primitive precursors were involved. Compared to CByB6F1 standard competitor cells, CXB-12 cells repopulated 3 to 12 times as well, with their advantage increasing when higher doses of cells were transplanted, probably because of hybrid resistance of the recipient against low doses. This was far better than expected, because F1 cells normally function 2 to 3 times as well as cells from an inbred strain. In competitive dilution, the advantage resulted from 2 factors: more precursor cells and more function per precursor. In the model that best fit the data, CXB-12 donors had 2.4 times the concentration of hematopoietic stem cells (HSCs) as the CByB6F1 standard, and each HSC repopulated 1.4 times as well. CXB-12 mice did not have elevated erythrocyte and lymphocyte numbers in blood and marrow and did not have unusually elevated concentrations of colony-forming unit spleen, cobblestone colonies, and long-term colony-initiating cells in marrow