The Japanese researcher and lead author of two recent papers on groundbreaking stem cell research that have been called into question gave a co-author stem cells produced from mice of different genetic lines than originally asked for, officials with the government-backed Riken institute said.
The episode raises further questions about the quality of research conducted by Haruko Obokata, a unit leader at the Riken Center for Developmental Biology who claimed her team had found a new, simple way to produce stem cells — called STAP cells (stimulus-triggered acquisition of pluripotency) — that can transform into any type of body tissue.
The papers, which appeared in the journal Nature in late January, have come under scrutiny due to a litany of problems, including images resembling those used in Obokata’s doctoral dissertation in 2011. The revelations have prompted Obokata and other co-authors at Riken to agree to have the papers retracted.
Before the papers were published, Teruhiko Wakayama, a co-author of the papers who is no longer at the Riken Center for Developmental Biology and is currently a professor at the University of Yamanashi, asked Obokata to create STAP stem cells using “129” mice, according to officials.
The purpose of Wakayama’s request was to see whether STAP cells could be produced regardless of mouse genetic lines. Obokata later provided two clusters of cells to Wakayama.
When Wakayama examined the genes of the two cell clusters, he discovered that they had come from “B6” and “F1” mice, not “129” mice, the officials said.
“We will proceed with a detailed examination in cooperation with Mr. Wakayama,” said Riken Director Masatoshi Takeichi, after Wakayama relayed his findings to the institute.
Wakayama, who was the first co-author of the papers to call publicly for their retraction, has sent the STAP stem cells he received to a third party for detailed analysis. STAP stem cells, purportedly produced by converting STAP cells, are claimed to have a proliferative quality that the latter do not possess.
Harvard Medical School professor Charles Vacanti, who was listed on Obokata’s doctoral dissertation as a member of the examination committee that approved it, told Nature this month he has not read the dissertation, according to the journal’s website.
“I was not presented with or asked to read a copy of her dissertation,” said Vacanti, who is also the senior corresponding author on the paper published in Nature, according to the website.