Non-canonical Wnt Signaling Enhances Differentiation of Human Circulating Progenitor Cells to Cardiomyogenic Cells

Abstract

Human endothelial circulating progenitor cells (CPCs) can differentiate to cardiomyogenic cells during co-culture with neonatal rat cardiomyocytes. Wnt proteins induce myogenic specification and cardiac myogenesis. Here, we elucidated the effect of Wnts on differentiation of CPCs to cardiomyogenic cells. CPCs from peripheral blood mononuclear cells were isolated from healthy volunteers and co-cultured with neonatal rat cardiomyocytes. 6 -10 days after co-culture, cardiac differentiation was determined by ␣-sarcomeric actinin staining of human lymphocyte antigen-positive cells (fluorescence-activated cell-sorting analysis) and mRNA expression of human myosin heavy chain and atrial natriuretic peptide. Supplementation of co-cultures with Wnt11-conditioned medium significantly enhanced the differentiation of CPCs to cardiomyocytes (1.7 ؎ 0.3-fold), whereas Wnt3A-conditioned medium showed no effect. Cell fusion was not affected by Wnt11-conditioned medium. Because Wnts inhibit glycogen synthase kinase-3␤, we further determined whether the glycogen synthase kinase-3␤ inhibitor LiCl also enhanced cardiac differentiation of CPCs. However, LiCl (10 mM) did not affect CPC differentiation. In contrast, Wnt11-conditioned medium time-dependently activated protein kinase C (PKC). Moreover, the PKC inhibitors bisindolylmaleimide I and III significantly blocked differentiation of CPCs to cardiomyocytes. PKC activation by phorbol 12-myristate 13-acetate significantly increased CPC differentiation to a similar extent as compared with Wnt11-conditioned medium. Our data demonstrate that Wnt11, but not Wnt3A, augments cardiomyogenic differentiation of human CPCs. Wnt11 promotes cardiac differentiation via the non-canonical PKC-dependent signaling pathway.

The Multiple Phases and Faces of Wnt Signaling During Cardiac Differentiation and Development

“…49,51 Overexpression of Wnt11 in Xenopus explants is sufficient to induce contractile tissue formation. 51 This cardiac promoting activity of Wnt11 has also been shown in other model systems such as quail mesoderm, 58,59 murine ES cells, 32,60 endothelial progenitor cells 61 and mesenchymal or bone marrow derived stem cells. [62][63][64] The cardiac supporting activity of Wnt11 could be linked to noncanonical Wnt signaling branches.…”

Bone marrow cells adopt the cardiomyogenic fate in vivo

“…The unmodified Cre-recombinase present in progenitor cells can cross the membrane of the recipient cell (25), mimicking fusion events. Also, this enzyme can be translocated via nanotubules (26) from BMCs carrying the Cre-recombinase to the resident cells, giving the false impression of cell fusion. Therefore, we have excluded cell fusion by documenting a diploid DNA content together with one set only of sex chromosomes in nuclei of newly formed myocytes, SMCs, and ECs.…”

Wnt2 Coordinates the Commitment of Mesoderm to Hematopoietic, Endothelial, and Cardiac Lineages in Embryoid Bodies

“…Inhibition of Wnt signaling by Dkk-1 induces heart-specific gene expression in posterior lateral plate mesoderm, and Wnt signals (Wnt3a and Wnt1) from the neural tube block heart formation in the adjacent paraxial mesoderm (32,33). However, noncanonical Wnt signaling mediated by Wnt11 is required for heart formation in Xenopus embryos (42), and promotes differentiation of both ES cells and circulating progenitors to cardiomyocytes (30,43). These studies suggest that canonical Wnt signaling is an inhibitory signal, whereas noncanonical Wnts may positively regulate cardiogenesis.…”