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Week in Review: February 23–27

Stem cells in culture; engineered cancer biomarkers; small molecule improves stem cell homing; reproducible bacterial evolution; how human adaptive immunity develops

Tracy Vence

Culturing stable stem cells

WIKIMEDIA, NISSIM BEVENISTYCulture conditions and cellular processing can impact the genetic changes that human embryonic stem cells (ESCs) undergo over time, according to a study published in PLOS ONE this week (February 25). A team led by investigators at the Scripps Research Institute in La Jolla, California, found that ESCs grown on a layer of feeder cells and passaged mechanically harbored less genetic variation than cells grown without a feeder layer and passaged chemically.

“I’m trying to get other people in the field to closely examine their cells before they do anything else with them,” said study coauthor Jeanne Loring of Scripps.

“The study is important in that it suggests that there are ways that we might avoid growing cells and having these abnormalities appear,” said stem-cell scientist Martin Pera of the University of Melbourne who was not involved in the work.

Stem cell homing...

WIKIMEDIA, ROBERT M. HUNTHuman mesenchymal stem cells (MSCs) pretreated with a certain small molecule are more likely to target inflamed tissue in mice, members of a public-private research collaboration led by investigators at Brigham and Women’s Hospital and Harvard Medical School showed in Cell Reports this week (February 26). The results point to a way researchers might increase the clinical utility of such cells.

“Generally speaking, MSCs do have great potential for tissue regeneration,” said Sophia Khaldoyanidi, a stem-cell biologist at the Torrey Pines Institute for Molecular Studies in San Diego, California, who was not involved in the work. “Unfortunately, the majority of clinical trials did not reach their full potential. In my opinion, this is mostly due to the fact that we didn’t learn everything about the basic biology of these cells, and we rushed quickly to clinical trials. The current study is so important because they really tried to understand how to make sure that cells actually go to the location where we want them to be.”

Engineered cancer biomarkers

WIKIMEDIA, TOM MALLINSONTumor cell-specific reporter proteins, which are triggered by tumor-activatable DNA-loaded vectors and can be detected in blood, may represent a new approach for finding cancer early, according to Stanford University researchers who published their findings in PNAS this week (February 23).

“It’s unconventional . . . that they tried to use an engineered biomarker,” said Andrei Drabovich of the University Toronto who was not involved in the study. “It’s probably not ready yet for screening applications in the general population, but you can definitely find some niche when it comes to cancer patients or suspected cancer patients.”

“I wouldn’t say that it would be so safe and with no concerns that we could apply it to everybody, but it does open up opportunities to screen high-risk patients,” added Shuk-Mei Ho of the University of Cincinnati, who also did not participate in the research.

Speedy, reproducible evolution

WIKIMEDIA, RIRAQ25Pseudomonas fluorescens bacteria that lack a protein vital for growing flagella can still produce the tail-like structures under pressure, researchers from University of Reading, U.K., reported in Science this week (February 26). The researchers also showed that independent P. fluorescens strains evolved the same adaptation similarly each time, by repurposing a distantly related protein.

“This is a fascinating set of evolution experiments,” evolutionary biologist Richard Lenski of Michigan State University told The Scientist. “Their experiments show how a biological function . . . can re-evolve after the deletion of a seemingly critical gene. The bacteria regained motility not by reacquiring the lost gene . . . but instead by mutations in other genes that put their products to new uses.”

Development of adaptive immunity

WIKIMEDIA, NEVITUsing next-generation sequencing and related approaches on B and T cells, investigators from Boston Children’s Hospital, Harvard Medical School, Sheba Medical Center, Tel Aviv University, and their colleagues have mapped the development of adaptive immunity throughout human fetal development. Their work was published in Science Translational Medicine this week (February 25).

“This is a very important study for increasing our fundamental knowledge on how both T- and B-cell immune diversity develops during fetal development,” said Barry Finette of the University of Vermont who was not involved in the work.

“It’s a nice and comprehensive survey,” echoed immunologist Harry Schroeder of the University of Alabama School of Medicine who also did not participate in the research.

Other news in life science:

UK OKs Three-Parent IVF
The British House of Lords has approved new rules regarding the creation of embryos using genetic material from three donors.

Indian Grad Students on Strike
With a promised pay hike delayed, thousands of Indian PhD students launch protests in New Delhi.

Rapid Ebola Test Approved
The World Health Organization OKs the first 15-minute Ebola diagnostic test.

HIV Scientist Pleads Guilty to Fraud
A former Iowa State University researcher faces up to 10 years in prison for faking data involving a study of an HIV vaccine.

New Tick-Borne Virus Discovered
Bourbon virus may have killed a previously healthy man in Kansas last year, the US Centers for Disease Control and Prevention reports.

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