Hello All as you
Hello all as you probably came acrossed my workshop post regarding a small segment from the introduction of my manuscript, and many of you provided great suggestions and comments to make it clearer so here I post up the revised section here for you to see the changes afterwards. The reviewers thought the writing was clear and easy to follow, thanks guys!
An effective treatment regimen for hematologic disease and malignancy has been challenging due to a lack of suitably-matched donors (1). To circumvent this issue, efforts have focused on generating hematopoietic stem and progenitor cells (HSPCs) from embryonic stem (ES) (2, 3) and induced pluripotent (iPS) cells (4, 5). However, the wide-spread application of pluripotent stem cells is currently hampered by their tumorigenic potential. A proposed alternative is the direct conversion of fibroblasts into HSPCs and blood cells (6, 7). Although lineage specification and reconstitution potential are currently inefficient (6, 7), evidence suggests that improvements in direct hematopoietic reprogramming could provide a viable strategy for hematopoietic based therapeutics. Aided by GFP reporters, recent studies demonstrated that overexpression of specific transcription factors facilitated generation of neurons and cardiomyocytes from fibroblasts (8, 9), suggesting the conversion of fibroblasts into functional HSPCs was plausible. These studies highlight the importance of having a reporter system for hematopoietic marking and a method to track cellular reprogramming.
Since the blood cell therapy field lacks a reliable reporter for hematopoietic production after differentiation of ES and iPS cells (5, 10), the development of a hematopoietic restricted marking system is essential. Furthermore, a fluorescent reporter system enables real time tracking of full reprogramming (11, 12), permits the study of reprogramming intermediates (13, 14), and may facilitate the eventual use of small molecules for direct reprogramming, as demonstrated recently for iPS cell derivation (15). Additionally, a reporter construct could aid in the purification and removal of undifferentiated pluripotent cells to minimize teratoma formation upon transplantation.
An effective reporter should be inactive in fibroblasts and pluripotent stem cells, but turned on in the desired reprogrammed cell fate. Transcription factors such as Gata2, Hoxb4 and Evi1 were previously employed as reporters due to their essential roles in HSPC genesis, maintenance and/or amplification (16-20). However these reporters were not limited to blood cell lineages, and this limited their utility (21, 22). Additionally, these transgenes used in the production of reporter mice (23) cannot be virally introduced into hematopoietic reconstituting cells because the reporter is too large for the viral backbone (24).
A mini introduction from my manuscript (also part of my thesis dissertation)
The development of a hematopoietic restricted marking system is essential since the blood cell therapy field is currently lacking a reporter, a reporter that can faithfully readout hematopoietic production following embryonic stem(ES) and induced pluripotent stem (iPS) cells based differentiation (1, 2). Additionally, this reagent is especially useful for efforts aimed at developing an efficient protocol for the direct reprogramming of fibroblasts into hematopoietic stem and progenitor cells (HSPCs). As cell transplantation, an effective treatment for hematologic disease and malignancy for decades (3), remains challenging due to a lack of suitably-matched donors. Recent efforts focus on generating HSPCs from ES cells (4, 5) and iPS cells (2, 6). The wide-spread application of pluripotent stem cells is currently hampered by the tumorigenic potential of undifferentiated pluripotent stem cells. A proposed alternative is the direct conversion of fibroblasts into HSPCs and blood cells (7, 8); However, lineage specification was inefficient (8) and multilineage reconstitution was not as robust (7). Current evidence suggests improvements in direct hematopoietic reprogramming could be a viable strategy for cell therapy. Overexpression of various transcription factors generated functional neurons, and cardiomyocytes from fibroblasts (9, 10).Not only these studies showed that fibroblasts can de-differentiate to another cell type, but showed that GFP reporter was an effective tool. Thus, regardless whether the study calls for pluripotent cells or fibroblasts to generate HSPC, a reliable hematopoietic marker is beneficial. Having a fluorescent reporter system enables real time tracking of full reprogramming (11, 12), allows reprogramming intermediates to be studied (13, 14), and can facilitate the eventual use of small molecules for direct reprogramming, as demonstrated recently for iPS cell derivation (15). Additionally, the reporter can aids in the purification of differentiated cells from the undifferentiated ones to minimize teratoma formation upon transplantation.