05 Mar 2014 01:20

Simple, new method for reprogramming body cells discovered

KOBE (Kyodo) -- A team of scientists led by a young Japanese female researcher has discovered that by simply exposing body cells to acidic liquids, the cells can be reprogrammed to grow into any type of mature tissue.

The discovery was announced in the journal Nature on Wednesday.

The new method, which differs from the one developed by Nobel Prize-winning Japanese scientist Shinya Yamanaka to create induced pluripotent stem cells, or iPS cells, could have a far-reaching impact on cancer research, regenerative medicine and new drugs.

The research was conducted by scientists at the state-backed Riken institute and Harvard University and led by 30-year-old Haruko Obokata, a scientist at Riken's Center for Developmental Biology in Kobe who also spent some time researching at Harvard.

In experiments, the scientists soaked lymph corpuscle taken from 7-day-old mice into mildly acidic liquids for about 30 minutes. A few cells that survived the environment were then cultured and transplanted into mice, where they developed into nerve and muscle tissues.

Under normal circumstances, cells that have matured into specific cells cannot be reprogrammed. But the researchers have discovered a new way of reprogramming adult cells. They named the method of generating pluripotent cells, or cells that can grow into any type of mature tissues in the body, "stimulus-triggered acquisition of pluripotency," or STAP.

The scientists say STAP cells can also become tissue that forms the placenta, something not possible with iPS cells that are created by injecting four gene control agents into an adult cell, or embryonic stem cells.

STAP cells can be produced within a shorter period of time than iPS cells, which can take several weeks to produce. The risk of STAP cells developing into cancer in the body is also believed to be lower than that of iPS cells.

The experiments were successful not just with lymph corpuscle but also with other body cells, such as those forming skin tissue, lungs and heart muscle.

Apparently, STAP cells are created under "sublethal" conditions where they are exposed to stimulus-induced stress.

Riken's Obokata told reporters that the new method "may lead to the regeneration of organs and tissues in the body and the development of new medical technology, such as one aimed at suppressing cancer that would be caused by stress on cells."

Researchers have been surprised by the discovery. "This is amazing. High-quality cells that could exceed the existing pluripotent stem cells have been created in an enormously simple way," said Arata Honda, associate professor at the University of Miyazaki, who was briefed on the research.

But much remains unknown about STAP cells, including why they can only be cultured but not created inside the body, and why such cells are created at all. Observers say it will take further research to see if the same thing can be done with human cells.

Obokata and her team are studying whether STAP cells can be produced with human cells and those of other animals.

January 30, 2014(Mainichi Japan)