Noncanonical Wnt11 Signaling Is Sufficient to Induce Cardiomyogenic Differentiation in Unfractionated Bone Marrow Mononuclear Cells

Abstract

Background— Despite the frequent clinical use of adult unfractionated bone marrow mononuclear cells (BMMNCs) for cardiac repair, whether these cells are capable of undergoing cardiomyogenic differentiation in vitro remains uncertain. In addition, the role of Wnt signaling in cardiomyogenic differentiation of adult cells is unclear. Methods and Results— Unfractionated BMMNCs were isolated from adult mice via Ficoll-Paque density-gradient centrifugation and cultured in the presence of Wnt3a or Wnt11. In control BMMNCs, Wnt11 was not expressed, whereas the expression of markers of pluripotency (Oct-4 and Nanog), as well as that of Wnt3a and β-catenin, decreased progressively during culture. Exposure to Wnt3a rescued β-catenin expression and markedly increased the expression of Oct-4 and Nanog, concomitant with increased cell proliferation and CD45 expression. In contrast, exposure to ectopically expressed noncanonical Wnt11 markedly decreased the expression of Oct-4 and Nanog and induced mRNA expression (quantitative real-time reverse-transcription polymerase chain reaction) of cardiac-specific genes (Nkx2.5, GATA-4, atrial natriuretic peptide, α- and β-myosin heavy chain, and cardiac troponin T) by day 3 with subsequent progression to a pattern characteristic of the cardiac fetal gene program. After 21 days, 27.6±0.6% and 29.6±1.4% of BMMNCs expressed the cardiac-specific antigens cardiac myosin heavy chain and cardiac troponin T, respectively (immunocytochemistry), indicating cardiomyogenic lineage commitment. Wnt11-induced cardiac-specific expression was completely abolished by the protein kinase C inhibitor bisindolylmaleimide I, partially abolished by the c-Jun-N-terminal kinase inhibitor SP600125, and attenuated by the Wnt inhibitor Dickkopf-1. Conclusions— In adult density-gradient separated BMMNCs, canonical Wnt3a promotes stemness, proliferation, and hematopoietic commitment, whereas noncanonical signaling via Wnt11 induces robust cardiomyogenic differentiation in a protein kinase C– and c-Jun-N-terminal kinase–dependent manner.

Enhancing the Outcome of Cell Therapy for Cardiac Repair

“…127 Subsequent studies reported that Wnt-11 or other noncanonical members of the Wnt family such as Wnt-5a induced or enhanced cardiac gene expression in a variety of adult progenitor cells, including circulating progenitor cells, 101,104 MSCs, 128 and unfractionated bone marrow-derived cells. 102 The downstream signaling events underlying noncanonical Wnt-induced cardiac gene expression are not entirely clear but include a protein kinase C-dependent pathway. 102,104 In contrast, the effect of canonical Wnts is rather complex.…”

“…102 The downstream signaling events underlying noncanonical Wnt-induced cardiac gene expression are not entirely clear but include a protein kinase C-dependent pathway. 102,104 In contrast, the effect of canonical Wnts is rather complex. The activation of ␤-catenin was initially shown to suppress cardiac differentiation during embryonic development, whereas cardiac differentiation was promoted in an in vitro model of a pluripotent mouse cell line.…”

We heart cultured hearts. A comparative review of methodologies for targeted differentiation and maintenance of cardiomyocytes derived from pluripotent and multipotent stem cells

“…[44]. Stimulation of non-canonical Wnt signaling was later shown to induce cardiomyogenic differentiation in mononuclear cells from bone marrow [45]. In 2013 was reported that cells isolated from murine amniotic fluid may be induced to differentiate to cardiomyocytes [46].…”

Gene and Cell Therapy for Heart Failure

“…The cells that have been applied to stimulate post-MI wound healing are of a greater variety in their origin than are the cells that have been transplanted into the chronically failing heart. Functional improvement after cell transplantation after MI has been demonstrated in preclinical and clinical studies for homogenous and heterogenous autologous cell populations from peripheral blood and bone marrow (33,97,113), cells of mesenchymal origin such as bone marrow stromal cells (28), adipose stromal cells (129), epicardium-derived cells (130), and mesenchymal progenitor cells (49), as well as cardiac progenitor cells (94) and stem cells (56). It is unclear whether these different cell types achieve functional improvement through a final common pathway or whether the improvement is the result of different mechanisms attributable to different progenitor cell types.…”