Just weeks after invalidating a groundbreaking paper describing a simple technique for generating pluripotent stem cells, professor Kenneth Ka Ho Lee now believes he has identified the correct approach.
Lee, chief of stem cell research at the Chinese University of Hong, spoke to Wired.co.uk in March about his tentative excitement when he read the Nature study in question, published at the start of the year. The proposed Stap cells (stimulus-triggered acquisition of pluripotency) in it were a revelation, because they suggested there was a simple way to generate embryonic-like stem cells that could potentially be used in the treatment of diseases such as Parkinson's. The method involved reprogramming a donor's own adult blood and skin cells (in this case, mice) by exposing them to extreme trauma, such as an acid bath.
Lee could see its potential, but like the rest of the community he had his doubts. While reports circulated that the images published in the Nature study also featured in older papers penned by lead researcher Haruko Obokata of Japan's Riken Centre, Lee set about trying to replicate the experiment himself.
It didn't work.
Since then the Riken Centre has launched an investigation into the legitimacy of the trial, and that investigation today revealed Obokata had indeed falsified information, including results and images of DNA fragments used.
"Actions like this completely destroy data credibility," commented Shunsuke Ishii, head of the investigative committee and a Riken molecular geneticist, at a press conference. "There is no doubt that she was fully aware of this danger. We've therefore concluded this was an act of research misconduct involving fabrication." Obokata has denied the allegations, but Riken says its own research team will be the one to verify the results and carry out the experiment again.
In the interim however, a coauthor on the paper at the centre of the debacle,Charles Vacanti published yet another protocol for the Stap technique. Vacanti, of ear-on-a-mouse fame, is a professor at Harvard Medical School and published online what he said was found to be "an effective protocol for generating Stap cells in our lab, regardless of the cell type being studied". It was a combination of the two approaches mentioned in the Naturepaper -- the acid bath, and the trituration process (the application of pressure on the cells using pipettes to induce stress). He describes the latter process as being exerted with force, more so than in the original paper, and over a lengthy period -- twice a day for the first week.
Nature had already rejected Lee's version of experiments for publication last month. Undeterred, he set about applying Vacanti's technique. Liveblogging the experiments on ResearchGate, the open source platform where Lee had published his first set of experiments, the Hong Kong researcher immediately saw the excess stress was leading to rapid cell death among the lung fibroblast cells used.
"We estimated that there was a 50 percent decrease in cell number," Lee wrote four days ago on the blog. "In the original paper reported in Nature, such decrease in cell count was reported for day two, which is inline with our current experiment. Day three will be critical as this was the time Oct4-GFP expression [an indication that stem cells are generating] was reported for Stap cells. If we find that the cell number decreased even more drastically in our cultures, we will harvest some of the cultures and use them directly for qPCR analysis [quantitative polymerase chain reaction,a screening technique for stem cells]."
Nevertheless, things appeared to turn around. In his preliminary studies Lee has concluded that it could be the extreme stress through trituration, and not the acid bath, that was responsible for creating the Stap cells. "I am shocked and amazed by the qPCR results for the three-day-old control and Stap cultures," he wrote on ResearchGate, alongside a graph of the results. "Totally speechless!"
Read more from the original source:
'Fabricated' stem cell paper may have just been proven valid
