Genetic Manipulation of Stem Cells

Abstract

Stem cells have the remarkable potential for self-renewal and differentiation into many cell types in the body during early life and development. In addition, in many tissues they constitute a source of internal repair system, dividing essentially without limit to replenish damaged or dead cells. After division, each new cell has the potential either to retain the stem cell status or to differentiate to a more specialized cell type, such as a red blood cell, a brain cell or a heart cell.Until recently, three types of stem cells from animals and humans have been characterized, i.e. embryonic stem cells, fetal stem cells and somatic adult stem cells. However, in late 2007, researchers accomplished another breakthrough by identifying conditions that allow some specialized adult cells to be "reprogrammed" genetically to assume a stem cell-like state. These cells, called induced pluripotent stem cells (iPSCs), express genes and factors important for maintaining the unique properties and features of embryonic stem cells.This review analyzes the mechanisms of genetic manipulation of stem cells, including the transfer of therapeutic genes into patients' cells via recombinant viral vectors for gene therapy purposes and discusses the mechanisms of generation and the resulting properties of induced pluripotent stem cells.