August 25, 2005

New Route to Reprogrammed Cells May Allow Study of ALS

Roberta Friedman, PhD, ALSA Research Department Information Coordinator

[QUICK SUMMARY: Fusion of embryonic stem cells and adult skin cells announced by Harvard researchers suggests new tool for finding ALS therapeutics]

Published in the August 26 issue of the journal Science, Harvard researchers report a new possibility to generate cells that act like stem cells with the ability to produce all types of cells in the body. The hybrids hold promise for finding new therapies, but the cells cannot be used themselves as therapeutics, as they contain double the number of human chromosomes and would be rejected by the body.

The fused product of a human embryonic stem cell and adult skin cell contain the genes from both cell types, but surprisingly, only the embryonic properties are expressed.

“This new technology gives us the means to develop cell lines that will allow drug discovery for ALS,” said Lucie Bruijn, Ph.D., science director and vice president of The ALS Association, because cells might be made that would reflect the biology of an ALS patient. “It’s an exciting tool to test new drugs and learn more about the disease mechanism,” Bruijn said.

The publication details the process of taking cells from an existing set of human embryonic stem cells growing in the lab and fusing these with human cells obtained from foreskins to produce a hybrid cell. The maneuver transfers the embryonic state to an adult cell.

Despite double the usual number of genes, the hybrids survive, grow, and can generate all sorts of cell types including muscle and nerve. The fusing technique also worked with bone cells, and for mouse as well as a separate human embryonic stem cell line.

Kevin Eggan, Ph.D. of the Harvard collaboration noted in a press conference Monday that “we can make a lot of these cells in a different way than with somatic cell nuclear transfer, and manipulate them” in the lab far more readily.

He was referring to work done by Korean scientists who have reprogrammed adult cells by taking donated human egg cells without a nucleus and inserting a nucleus from an adult cell. This process is called somatic cell nuclear transfer. Somehow the egg’s cytoplasm can produce the embryonic state despite the adult genes present. 

The Harvard researchers write in their report that understanding how reprogramming works might allow conversion of adult cells into stem cells “and thus the production of genetically tailored cell lines for the study and treatment of human disease.”

ALS researchers envision studying the disease by placing a nucleus from a cell from ALS patients into cells that can live in the lab to generate cell lines that are more representative of ALS.