Renal lineage cells as a source for renal regeneration.

The mammalian kidney is a highly complex organ, composed of various cell types within a unique structural framework. Nonetheless, in recent years, giant leaps in our understanding of nephrogenesis and the origin of new cells in the adult kidney have resulted in novel routes to regenerate damaged nephrons. While several strategies can be envisioned to achieve this aim, one common theme is the reliance on renal lineage cells, as extrarenal cells, such as bone marrow-derived cells, have been shown to be devoid of renal differentiation capacity. Herein, we will present the main motivation for the pursuit for cell-based therapies, which is the ever growing problem of chronic kidney disease (CKD), and discuss different strategies toward replenishing the damaged renal parenchyma. These include transplantation of fetal kidney grafts or fetal kidney stem cells, directed differentiation of pluripotent stem cells into kidney epithelia, establishment of renal progenitors from the adult kidney, and genetic reprogramming of mature kidney cells into a progenitor state. Taken together with novel techniques recapitulating the three-dimensional developmental environment, these advances are expected to take the field into a new era, bringing us closer than ever to the day when kidney stem cell-based therapy becomes a viable therapeutic option.