Adult telomerase positive stem cells: Effects of biological agents and characterization criteria on genomically-labeled clones and unlabeled clones of adult cells

The adult human body is composed of trillions and trillions of cells. These cells can be divided into three categories: telomerase negative differentiated cells, telomerase negative progenitor cells, and telomerase positive stem cells (aTPSCs). The aTPSCs are uniquely different from differentiated cells and progenitor cells, due mainly to not conforming to standard tissue culture practices, their limited number in the body, and the presence of the telomerase enzyme. Therefore, special technologies were developed to examine aTPSCs in vitro, which have been extensively outlined in recent publications. The aTPSCs and a Tripotent progenitor cell, e.g., mesenchymal stem cell (MSC), were cloned from single cells using repetitive single cell clonogenic analysis with 5-6x exosome-conditioned medium. These clones were examined with proliferation, progression, induction, and anti-differentiation biological agents to assess their particular responses. As noted, both aTPSCs and MSC clones responded similarly to proliferation and anti-differentiation agents, but differently with respect to progression and induction agents. The aTPSC clones were subsequently genomically-labeled with the Lac-Z gene for beta-galactosidase, using lipofection, to track the cells both in vitro and in vivo. This study was undertaken to determine if genomically labelling of aTPSCs caused any alteration in their response to 1. human recombinant proteins, morphogenetic proteins isolated from both demineralized bone matrix and sera, and cell-specific exosome conditioned media for the four activities of biological agents, e.g., proliferation, progression, induction, and anti-differentiation, and 2. standardized procedures for characterizing aTPSCs and MSCs.