Generation of human induced pluripotent stem cells from urine samples

Generation of human induced pluripotent stem cells from urine samples

Nature Protocols

PHOTO: Morphology of urinary cells at different time points after collection.
(a) Fresh female urine samples mainly consist of squamous cells and a few blood cells (arrowheads). (b) Fresh male urine samples mainly contain a few blood cells (arrowhead). (c–h) Type I (c,e,g) and type II (d,f,h) urinary cell colonies (arrowheads) at days 4 (c,d), 9 (e,f) and 12 (g,h). Representative images are shown in a–h; scale bars, 400 μm.

Human induced pluripotent stem cells (iPSCs) have been generated with varied efficiencies from multiple tissues. Yet, acquiring donor cells is, in most instances, an invasive procedure that requires laborious isolation. Here we present a detailed protocol for generating human iPSCs from exfoliated renal epithelial cells present in urine. This method is advantageous in many circumstances, as the isolation of urinary cells is simple (30 ml of urine are sufficient), cost-effective and universal (can be applied to any age, gender and race). Moreover, the entire procedure is reasonably quick—around 2 weeks for the urinary cell culture and 3–4 weeks for the reprogramming—and the yield of iPSC colonies is generally high—up to 4% using retroviral delivery of exogenous factors. Urinary iPSCs (UiPSCs) also show excellent differentiation potential, and thus represent a good choice for producing pluripotent cells from normal individuals or patients with genetic diseases, including those affecting the kidney.

Stem Cell Potency Definitions

PHOTO: Pluripotent, embryonic stem cells originate as inner cell mass (ICM) cells within a blastocyst. These stem cells can become any tissue in the body, excluding a placenta. Only cells from an earlier stage of the embryo, known as the morula, are totipotent, able to become all tissues in the body and the extraembryonic placenta.

Potency specifies the differentiation potential (the potential to differentiate into different cell types) of the stem cell.

• Totipotent (a.k.a. omnipotent) stem cells can differentiate into embryonic and extraembryonic cell types. Such cells can construct a complete, viable organism. These cells are produced from the fusion of an egg and sperm cell. Cells produced by the first few divisions of the fertilized egg are also totipotent.
• Pluripotent stem cells are the descendants of totipotent cells and can differentiate into nearly all cells,i.e. cells derived from any of the three germ layers.
• Multipotent stem cells can differentiate into a number of cells, but only those of a closely related family of cells
• Oligopotent stem cells can differentiate into only a few cells, such as lymphoid or myeloid stem cells.
• Unipotent cells can produce only one cell type, their own,but have the property of self-renewal, which distinguishes them from non-stem cells (e.g., muscle stem cells).