Conversion of human fibroblasts to angioblast-like progenitor cells

Abstract

Lineage conversion of one somatic cell type into another constitutes an attractive approach for research and clinical use. Lineage conversion can proceed in a direct manner, in the absence of proliferation and multipotent progenitor generation, or in an indirect manner, by the generation of expandable multipotent progenitor states. Here we report on the development of a combined reprogramming methodology that, transitioning through a plastic intermediate state, allows for the generation of human mesodermal progenitor cells while circumventing the traditional hallmarks of pluripotency. Converted mesodermal progenitor cells demonstrated bi-potent differentiation potential and were able to generate endothelial and smooth muscle lineages. Importantly, human fibroblasts can be converted into angioblast-like progenitor cells by non-integrative approaches. Differentiated angioblast-like cells exhibit neo-angiogenesis and anastomosis in vivo. The methodology for indirect lineage conversion to angioblast-like cells described here adds to the armamentarium of reprogramming approaches aimed at the clinical treatment of ischemic pathologies.

Direct Conversion of Adult Skin Fibroblasts to Endothelial Cells by Defined Factors

“…8 The direct conversion of adult cells into ECs can provide new therapeutic modalities to overcome the hurdles associated factors (OCT4, SOX2, KLF4, and c-MYC) 24,25 can convert human fibroblasts into ECs without inducing pluripotent status. [30][31][32] However, because conversion by these techniques involves the generation of intermediate progenitor cells or partial iPSCs, these are essentially different from our direct conversion technology. Moreover, because these studies used pluripotent factors, there are still concerns about their tumorigenic potential.…”

Direct lineage reprogramming via pioneer factors; a detour through developmental gene regulatory networks

“…This creates a primary spatial organization within Pioneer transcription factors have been used in many instances of direct conversion of cell fate between differentiated states, both in mouse and human. These include the conversion of fibroblasts to cardiomyocytes (Ieda et al, 2010), hepatocytes (Huang et al, 2011;Sekiya and Suzuki, 2011;Zhu et al, 2014), glutamatergic neurons (Ambasudhan et al, 2011;Pang et al, 2011;Vierbuchen et al, 2010;Yoo et al, 2011), dopaminergic neurons (Caiazzo et al, 2011;Pfisterer et al, 2011), motor neurons (Son et al, 2011), hematopoietic progenitors (Pereira et al, 2013;Szabo et al, 2010), neural progenitors (Lujan et al, 2012;Thier et al, 2012), bipotent hepatic progenitors (Yu et al, 2013), angioblast-like progenitor cells (Kurian et al, 2013) and osteoblasts (Yamamoto et al, 2015). Other cell type conversions (not shown) include hepatocyte to neuron conversion , and cortical astrocytes to glutamatergic (Heinrich et al, 2010) and GABAergic (Berninger et al, 2007;Heinrich et al, 2010) neurons.…”

“…Conversion from fibroblasts to hematopoietic progenitors (Pereira et al, 2013;Szabo et al, 2010), to neuronal stem/precursor cells (Lujan et al, 2012;Thier et al, 2012), to bipotent hepatic progenitors (Yu et al, 2013), to angioblast-like progenitor cells (Kurian et al, 2013) and to osteoblasts (Yamamoto et al, 2015), and conversion from proximal tubule cells to nephron progenitors have all been achieved via transcription factor-mediated lineage reprogramming. Several recent methodologies have relied on a transient burst of Yamanaka factor expression, with the intention to direct cell fate to an alternative lineage before the pluripotent state is reached (Kurian et al, 2013;Thier et al, 2012;Zhu et al, 2014). Recently, however, two elegant studies have demonstrated that these cells do in fact passage through a pluripotent state (Bar-Nur et al, 2015;Maza et al, 2015).…”

Preexisting endothelial cells mediate cardiac neovascularization after injury

“…Unraveling new sources of vascular endothelial cells in the heart provides important insights into therapeutic deployment for cardiac regeneration (3). One paradigm in the field for promoting neovascularization is generation of new blood vessels through lineage conversion from other types of differentiated cells (4). Fibroblasts are regarded as terminally differentiated cells, and excessive new fibroblasts are accumulated after tissue injury, such as myocardial infarction (5,6).…”