A new way to turn adult human cells into ultra-flexible stem cells could make it easier to produce them in large quantities and make them more effective at treating disease.
Stem cells can develop into any of the cells within our bodies. 快猫短视频s have long hoped to exploit this ability by programming stem cells to become specific cells for use in treatments.
But acquiring stem cells can be difficult. One method is to take them from embryos before they implant into the uterus, but the controversy involved in doing so set researchers looking at an alternative: inducing adult human cells to reprogram themselves back into stem cells which can be turned into all types of cells that make up the body 鈥� also known as pluripotent stem cells.
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This method comes with its own problems because it isn鈥檛 a complete reprogramming, says at the University of Western Australia. Instead, some of these newly induced stem cells retain residual DNA markers of their original adult human cells, he says.
These markers can make it harder to convert induced stem cells into new types of cells and can cause the resulting cells to act in undesired ways, says Lister.
Such issues don鈥檛 occur in stem cells taken from embryos, however, because there is a phase early in human development when the chemical modifications of DNA 鈥� also known as the epigenome 鈥� from the sperm and egg are reset and erased, says Lister. 鈥淚t essentially wipes the slate clean,鈥� he says.
While we already know how to induce adult cells into stem cells that resemble those found in preimplantation embryos, existing methods are unable to do so at scale and without producing cells with anomalies, says Lister.
Lister and his colleagues wanted to try and combine both methods so that the induced stem cells have fewer residual DNA markers from their original cell state but are also able to be easily cultured and turned into new cell types that avoid anomalies.
The team found that the best method was to first induce the human cells to become stem cells in the typical way, culturing them for seven days. The cells were then transferred into a second culture medium containing chemicals designed to make the stem cells more closely resemble those found in an embryo preimplantation. After five days in this second culture medium, the team returned the cells to the original culture medium type for just over two weeks.
This five-day transfer removes most of the residual DNA markers, says Lister. 鈥淚n this way, we mimic the natural process of how the epigenome resets in the early embryo,鈥� he says.
The researchers also compared stem cells produced in this new way, which they called the transient naive treatment (TNT), to those produced in the typical way, by inducing them to become various types of adult cell such as neurons and those in skeletal muscle. The team found that the TNT method led to a higher conversion rate than the typical method.
at Stanford University in California says this new method could lead to more effective and safer therapeutic interventions using induced stem cells. 鈥淭hese findings are a significant step towards harnessing induced pluripotent stem cells鈥� potential for various scientific and clinical purposes,鈥� says Wu.
Nature
