(CUMC/New York Stem Cell Foundation) A team of scientists from Hebrew University, Columbia University Medical Center and The New York Stem Cell Foundation Research Institute (NYSCF) have found a way to create human stem cells with only 23 chromosomes, rather than the usual 46. This greatly enhances the ability to study genetic mutations and create therapies for diseases such as Tay-Sachs.
Researchers have been limited by the fact that human cells are diploid, meaning they contain two copies of the human genome. The discovery of a haploid cell with only 23 chromosomes makes it simpler for scientists to isolate and study genetic mutations without the “interference” of the second set. And, unlike the diploid cells, they may be used to create human embryonic stem cells that can be used to duplicate many other cell types, including nerve, heart, and pancreatic cells—all while retaining a single set of chromosomes.
“We showed that the haploid stem cells are a powerful tool for genetic screens, and thus can unravel interactions between the gene causing the disorder and other genes in the genome,” said the lead scientist, Dr. Nissim Benvenisty of Hebrew U of the discovery, which was published in the journal Nature.
The advantages for medical science include:
GENETIC SCREENING: Because they have just a single copy of a gene to target, haploid human cells may constitute a powerful tool for genetic screens. “Being able to affect single-copy genes in haploid human stem cells has the potential to facilitate genetic analysis in biomedical fields such as cancer research, precision and regenerative medicine,” said Prof. Nissim Benvenisty, Director of the Azrieli Center for Stem Cells and Genetic Research at the Hebrew University of Jerusalem and principal co-author of the study. “One of the greatest advantages of using haploid human cells is that it is much easier to edit their genes,” said Ido Sagi, the PhD student who led the research at the Azrieli Center for Stem Cells and Genetic Research at the Hebrew University of Jerusalem.
CELL-BASED THERAPIES: Since the stem cells described in this study were a genetic match to the egg cell donor, they could be used to develop cell-based therapies for diseases such as blindness, diabetes or other conditions in which genetically identical cells offer a therapeutic advantage.
REPRODUCTIVE SCIENCE: Because their genetic content is equivalent to germ cells, these cells will provide researchers with a novel tool for understanding human development and the reasons why we reproduce sexually, instead of from a single parent, and could have implications for human reproductive therapies.
Previous efforts to generate embryonic stem cells using human egg cells had resulted in diploid stem cells. In this study, the scientists triggered unfertilized human egg cells into dividing. They then highlighted the DNA with a fluorescent dye and isolated the haploid stem cells, which were scattered among the more populous diploid cells.
The Israeli research team was led by Prof. Nissim Benvenisty, Director, and Ido Sagi, PhD student, at the Azrieli Center for Stem Cells and Genetic Research at the Hebrew University of Jerusalem. The US team was led by Prof. Dieter Egli, Columbia University Medical Center and New York Stem Cell Foundation Research Institute.
The research was supported by The New York Stem Cell Foundation, the New York State Stem Cell Science Program, and by the Azrieli Foundation, underscoring the importance of private philanthropy in advancing cutting-edge science.
