The cardiomyocyte lineage is critical for optimization of stem cell therapy in a mouse model of myocardial infarction

Abstract

We recently described a murine embryonic stem cell (ESC) line engineered to express the activated Notch 4 receptor in a tetracycline (doxcycline; Dox) regulated fashion (tet-notch4 ESCs). Notch 4 induction in Flk1(+) hematopoietic and vascular progenitors from this line respecified them to a cardiovascular fate. We reasoned that these cells would be ideal for evaluating the contribution of the cardiomyocyte and vascular lineages to the functional improvement noted following stem cell transplantation in infarcted hearts. Flk-1(+) Tet-notch4 cells from d 3 embryoid bodies exposed to doxycycline (Dox(+)) were compared to uninduced (Dox(-)) Flk-1(+) cells. Mice underwent transplantation of 5 x 10(5) Dox(+) cells, Dox(-)cells, or an equal volume of serum-free medium after surgically induced myocardial infarction. The mean ejection fraction was 59 + or - 15, 46 + or - 17, and 39 + or - 13% in the Dox(+), Dox(-), and serum-free medium groups, respectively (P<0.05 for the differences among all 3 groups). Immunohistochemistry of hearts injected with Dox(+) grafts expressed myocardial and vascular markers, whereas grafts of Dox(-) cells expressed primarily vascular markers. We conclude that cardiovascular progenitors are more effective than vascular progenitors in improving function after myocardial infarction. The transplantation of appropriate cell types is critical for maximizing the benefit of cardiovascular cell therapy.-Adler, E. D., Chen, V. C., Bystrup, A., Kaplan, A. D., Giovannone, S., Briley-Saebo, K., Young, W., Kattman, S., Mani, V., Laflamme, M., Zhu, W.-Z., Fayad, Z., Keller, G. The cardiomyocyte lineage is critical for optimization of stem cell therapy in a mouse model of myocardial infarction.

Cardiopoietic Factors

“…266 Given to infarcted mice, these Notch4-activated cells generate more cardiac muscle in vivo than control cells and a greater benefit to cardiac pump function. 267 Because these cardiogenic effects resemble the findings in Rpbj-deficient ESCs, it was surmised that Notch might activate cardiogenesis via mechanisms independent of Rbpj, such as its known interaction with Smads 233,268 or Dvl. 234 Most neonatal mouse cardiac progenitor cells expressing c-kit coexpress Notch1, and in these cells, immobilized Jagged-1 or the NICD induces Nkx2-5, possibly by direct binding of Rbpj to the Nkx2-5 promoter.…”

Cardiac Tissue Engineering

“…Monkey ES cell-derived cardiomyocyte precursors differentiated into cardiomyocytes, and replaced 1/5 of a cardiac scar in primates 8 . MESC derived cardiomyocytes transplanted in rodent hearts (Adler et al, 2010;Christoforou et al, 2010;Lu et al, 2010b), and sheep hearts , also contributed to cardiac repair.…”

“…Dissection of beating clusters (Asp et al, 2010;Caspi et al, 2009;Passier et al, 2005;Segev et al, 2005), procedures taking advantage of differences in cardiomyocyte density Xu et al, 2002), fluorescent or antibiotic selection of transgenic cultures Huber et al, 2007;Kita-Matsuo et al, 2009;Xu et al, 2008b), cell sorting based on mitochondrial activity (Hattori et al, 2009), cell sorting using an antibody-based approach with lineage restricting cell surface proteins (Adler et al, 2010;Nelson et al, 2008;Yang et al, 2008), and cell sorting using an antibody-based approach with cardiomyocyte lineage specific cell surface proteins Honda et al, 2006;Rust et al, 2009;Van Hoof et al, 2010). Finally, as summarized in section 1.3.2, the directed differentiation approach has led to high cardiomyocyte culture purities, and can be combined with all of the aforementioned purification strategies.…”

“…Keller at the University of Toronto (Adler et al, 2010;Yang et al, 2008). Embryonic mouse cell tracking and ESC differentiation studies have lead many groups to believe that myocardial and endothelial lineages develop from a common Flk-1-positive progenitor (Kattman et al, 2006).…”

“…The Flk-1 positive cell population isolated from mESCs differentiates into a higher portion of cardiac muscle than the Flk-1-negative cell population in vivo, however this marker was not specific enough on its own to generate a pure population of precursors cells that exclusively differentiated into cardiomyocytes (Baba et al, 2007a;Baba et al, 2007b;Iida et al, 2005;Nelson et al, 2009). When Flk1+ mESCs were transplanted in vivo into the hearts of a cardiomyopathic mouse, significant improvement in cardiac function was recorded (Adler et al, 2010;Baba et al, 2007b). Kdr has also been used to isolate populations of differentiating hESCs.…”