Induced pluripotent stem cells: the wonders of training

Researchers from the University of Nebraska, led by Dr. Iqbal Ahmad, managed to prove that somatic cells of the cornea of the eye can be reprogrammed into induced pluripotent stem cells without using transcription factor genes and their protein products, but by changing the microenvironment in which the cells are cultured.

For reprogramming, scientists isolated progenitor cells from the eyes of laboratory rats, localized in the limbal epithelium - a ring of cells located between the cornea and the mucous membrane of the eye. Due to them, there is a constant renewal of the corneal tissue.

The reprogramming process consisted of two stages. At the first stage, the expression of their own genes Klf4, Sox2 and c-Myc was induced in the cells. In specialized cells, these "pluripotency genes" are in a latent state, and in many experiments to create induced pluripotent stem cells, their working copies were injected into specialized cells. Researchers from Nebraska achieved the activation of these three genes by adding the regulatory proteins FGF2 (fibroblast growth factor, fibroblast growth factor) and Noggin (Eng. "head" – it plays a key role in the coordination of other signaling proteins during embryo development) to the culture medium. At the second stage, the cells were transferred to an environment in which embryonic stem cells had been cultured for some time before. The currently unknown products of their vital activity activated the expression of two more "embryonic" genes, Oct4 and Nanog, and effectively supported the expression of all four genes responsible for the state of pluripotency (Oct4, Klf4, Sox2 and c-Myc).

The results of the work are published in the journal Stem Cells in the article "Non Cell-autonomous Reprogramming of Adult Ocular Progenitors: Generation of Pluripotent Stem Cells without Exogenous Transcription Factors".

The authors believe that their development can accelerate the introduction of induced pluripotent stem cells into clinical practice. Limbal progenitor cells can be isolated from tissue obtained during a 2 mm limbal biopsy that does not disrupt the patient's vision, and the cells resulting from reprogramming can be used to restore neurons, cardiomyocytes and hepatocytes.

In the near future, the researchers plan to test the stability of the reprogramming results and analyze the composition of the microenvironment created by embryonic stem cells.

Evgeniya Ryabtseva
Portal "Eternal youth" http://vechnayamolodost.ru based on Genetic Engineering & Biotechnology News: Researchers Create iPSCs from Somatic Cells without Exogenous Transcription Factors

26.10.2009