Single-cell qPCR facilitates the optimization of hematopoietic differentiation in hPSCs/OP9 coculture system

Human pluripotent stem cells (hPSCs)/OP9 coculture system is a widely used hematopoietic differentiation approach. The limited understanding of this process leads to its low efficiency. Thus, we used single-cell qPCR to reveal the gene expression profiles of individual CD34+ cells from different stages of differentiation. According to the dynamic gene expression of hematopoietic transcription factors, we overexpressed specific hematopoietic transcription factors (Gata2, Lmo2, Etv2, ERG, and SCL) at an early stage of hematopoietic differentiation. After overexpression, we generated more CD34+ cells with normal expression level of CD43 and CD31, which are used to define various hematopoietic progenitors. Furthermore, these CD34+ cells possessed normal differentiation potency in colony-forming unit assays and normal gene expression profiles. In this study, we demonstrated that single-cell qPCR can provide guidance for optimization of hematopoietic differentiation and transient overexpression of selected hematopoietic transcription factors can enhance hematopoietic differentiation.

Functional disruption of human leukocyte antigen II in human embryonic stem cell

BACKGROUND: Theoretically human embryonic stem cells (hESCs) have the capacity to self-renew and differentiate into all human cell types. Therefore, the greatest promise of hESCs-based therapy is to replace the damaged tissues of patients suffering from traumatic or degenerative diseases by the exact same type of cells derived from hESCs. Allo-graft immune rejection is one of the obstacles for hESCs-based clinical applications. Human leukocyte antigen (HLA) II leads to CD4+ T cells-mediated allograft rejection. Hence, we focus on optimizing hESCs for clinic application through gene modification. RESULTS: Transcription activator-like effector nucleases (TALENs) were used to target MHC class II transactivator (CIITA) in hESCs efficiently. CIITA(-/-)hESCs did not show any difference in the differentiation potential and self-renewal capacity. Dendritic cells (DCs) derived from CIITA(-/-)hESCs expressed CD83 and CD86 but without the constitutive HLA II. Fibroblasts derived from CIITA(-/-)hESCs were powerless in IFN-γ inducible expression of HLA II. CONCLUSION: We generated HLA II defected hESCs via deleting CIITA, a master regulator of constitutive and IFN-γ inducible expression of HLA II genes. CIITA(-/-)hESCs can differentiate into tissue cells with non-HLA II expression. It's promising that CIITA(-/-)hESCs-derived cells could be used in cell therapy (e.g., T cells and DCs) and escape the attack of receptors' CD4+ T cells, which are the main effector cells of cellular immunity in allograft.