Abstract
BackgroundDefinite identification of the cell types and the mechanism relevant to cardiomyogenesis is essential for effective cardiac regenerative medicine. We aimed to identify the cell populations that can generate cardiomyocytes and to clarify whether generation of donor-marker+ cardiomyocytes requires cell fusion between BM-derived cells and recipient cardiomyocytes.Methodology/Principal FindingsPurified BM stem/progenitor cells from green fluorescence protein (GFP) mice were transplanted into C57BL/6 mice or cyan fluorescence protein (CFP)-transgenic mice. Purified human hematopoietic stem cells (HSCs) from cord blood were transplanted into immune-compromised NOD/SCID/IL2rγnull mice. GFP+ cells in the cardiac tissue were analyzed for the antigenecity of a cardiomyocyte by confocal microscopy following immunofluorescence staining. GFP+ donor-derived cells, GFP+CFP+ fused cells, and CFP+ recipient-derived cells were distinguished by linear unmixing analysis. Hearts of xenogeneic recipients were evaluated for the expression of human cardiomyocyte genes by real-time quantitative polymerase chain reaction. In C57BL/6 recipients, Lin−/lowCD45+ hematopoietic cells generated greater number of GFP+ cardiomyocytes than Lin−/lowCD45− mesenchymal cells (37.0+/−23.9 vs 0.00+/−0.00 GFP+ cardiomyocytes per a recipient, P = 0.0095). The number of transplanted purified HSCs (Lin−/lowSca-1+ or Lin−Sca-1+c-Kit+ or CD34−Lin−Sca-1+c-Kit+) showed correlation to the number of GFP+ cardiomyocytes (P<0.05 in each cell fraction), and the incidence of GFP+ cardiomyocytes per injected cell dose was greatest in CD34−Lin−Sca-1+c-Kit+ recipients. Of the hematopoietic progenitors, total myeloid progenitors generated greater number of GFP+ cardiomyocytes than common lymphoid progenitors (12.8+/−10.7 vs 0.67+/−1.00 GFP+ cardiomyocytes per a recipient, P = 0.0021). In CFP recipients, all GFP+ cardiomyocytes examined coexpressed CFP. Human troponin C and myosin heavy chain 6 transcripts were detected in the cardiac tissue of some of the xenogeneic recipients.Conclusions/SignificanceOur results indicate that HSCs resulted in the generation of cardiomyocytes via myeloid intermediates by fusion-dependent mechanism. The use of myeloid derivatives as donor cells could potentially allow more effective cell-based therapy for cardiac repair.
Highlights
Modification of regenerative capacity in injured heart could be potentially alternative to conventional therapy for treating patients suffering from heart failure [1,2,3,4,5,6,7]
We detected green fluorescence protein (GFP)+ cells preferentially located adjacent to the injured cites
Cardiomyocytes were counted by their specific intracellular striated structure and longer diameter compared with hematopoietic cells
Summary
Modification of regenerative capacity in injured heart could be potentially alternative to conventional therapy for treating patients suffering from heart failure [1,2,3,4,5,6,7]. Based on the promising results in rodents [3,4], clinical trials of cellular therapy using bone marrow (BM) cells for ischemic heart disease patients have been designed. BM contains heterogeneous cell populations including at least two distinct stem cells, hematopoietic stem cells (HSCs) and mesenchymal stem cells (MSCs) [9], and various progenitors of myeloid and lymphoid lineages. Both HSCs and MSCs have been reported to acquire the phenotype of cardiomyocytes in syngeneic or xenogeneic recipients [4,10,11,12,13]. We aimed to identify the cell populations that can generate cardiomyocytes and to clarify whether generation of donor-marker+ cardiomyocytes requires cell fusion between BM-derived cells and recipient cardiomyocytes
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.