Adult telomerase positive stem cells: Effects of biological agents on single cell 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. Within the body, both aTPSCs and progenitor cells, including MSCs, respond to environmental cues (biological activities) dictating their ability to repair/regenerate damaged cells and tissues. Four biological activities were noted during the repair/regeneration process, e.g., proliferation, progression, induction, and anti-differentiation. This study was designed to test these four biological activities on the single cell generated clones to determine their response. We utilized human recombinant proteins, morphogenetic proteins isolated from both demineralized bone matrix and sera, and cell-specific exosome conditioned media to test the hypothesis that aTPSCs and MSCs react both similarly and differently to biological activities inherent in the body, e.g., proliferation, progression, induction, and anti-differentiation.