The Galat laboratory at Stanley Manne Children's Research Institute, Ann & Robert H. Lurie Children's Hospital of Chicago, has developed an elegant system to derive blood cell precursors from human pluripotent stem cells (hPSC). This type of stem cell has the potential to develop into many different kinds of cells in the body, and is capable of participating in organ repair and function. These qualities have prompted scientists to test the use of hPSC to treat some diseases. However, the development of a fully defined system to generate functional blood cell precursors has proven to be a significant challenge. The Galat lab's findings hold promise to overcome this challenge.
The approach is reliable, cost-effective and relatively simple. By eliminating variables used in other systems, the lab has streamlined the process of developing blood cell precursors. This allows scientists to study the factors that affect early stages of blood cell development, and provides a mechanism for clinician-researchers to develop therapies for patients.
In a series of experiments, the lab converted adult skin cells into hPSC and then used these patient specific cells to optimize their platform of blood cell precursor derivation. Various assays were employed in order to demonstrate the ability of blood cell precursors to form mature cells of blood lineage. The cells were identified in collaboration with immunology labs at Lurie Children's and Rosalind Franklin University.
A description of the work, entitled "Cytokine Free Directed Differentiation of hPSC Efficiently Produces Hemogenic Endothelium With Lymphoid Potential," is published online in the journal Stem Cell Research & Therapy.
Previously, scientists have relied on the introduction of external factors - proteins or cells - to induce hPSC to differentiate. In addition to potentially changing the outcomes, these factors can complicate the experimental setup and cause inefficiencies or bias in the generation of blood cell precursors.
"We designed the platform to exclude as many factors that can cause variability in the differentiation outcome as possible. These factors include co-culturing the hPSC with non-human animal cells that secrete an un-measurable amount of substances into the media, which is used to promote differentiation. We also excluded cytokines - proteins that affect hPSC differentiation in various ways depending on their quality," says Yekaterina Galat, first author on the publication. "We demonstrated that the unique approach we developed efficiently promotes differentiation of hPSC to blood cell precursors, while eliminating many complications," she continues.
Co-senior author Philip M. Iannaccone, MD, PhD, says, "Importantly, this novel induction system, grown on one layer, avoids unwarranted effects associated with cellular interactions that happen in 3D cultures, as well as excessive priming by multiple cytokines, which complicates studies of developmental and functional aspects of the formation of blood cells, and their specifications." Iannaccone is Professor of Pediatrics at Northwestern University Feinberg School of Medicine and director of the Developmental Biology Program at the Manne Research Institute.
Says corresponding author and laboratory director Vasil Galat, PhD, "Our hope is to leverage this platform so that we can help other scientists and clinicians. The cells we derive can be used to study factors for their effects on hPSC differentiation, paving the way for studies of drug efficacy and toxicity, and to model diseases. We envision, for example, the ability to take blood cells from a patient, correct the genetic defects in the lab, and then re-introduce them into the patient. It is hoped that processes such as this can be used to treat blood disorders."
Galat's lab is currently working with Ramsay Fuleihan, MD, an attending physician in the Division of Allergy and Immunology and the director of Primary Immunodeficiency Clinical Services at Lurie Children's, on a project to derive patient cells, fix the mutation causing immune deficiency and differentiate the cells into healthy blood lineage.