Efficient model for generating human iPSCs developed

Aug 01, 2013
This graphic depicts single RNA generation of human iPS cells. Credit: Peter Allen, UC Santa Barbara.

Researchers at the University of California, San Diego School of Medicine report a simple, easily reproducible RNA-based method of generating human induced pluripotent stem cells (iPSCs) in the August 1 edition of Cell Stem Cell. Their approach has broad applicability for the successful production of iPSCs for use in human stem cell studies and eventual cell therapies.

Partially funded by grants from the California Institute for Regenerative Medicine (CIRM) and the National Institutes of Health (NIH), the methods developed by the UC San Diego researchers dramatically improve upon existing DNA-based approaches – avoiding potential integration problems and providing what appears to be a safer and simpler method for future clinical applications.

The generation of iPSCs has opened the potential for regenerative medicine therapies based on patient-specific, personalized stem cells. Pluripotent means that these cells have the ability to give rise to any of the body's cell types. The human iPSCs are typically artificially derived from a non-pluripotent , such as a skin cell. They retain the characteristics of the body's natural , commonly known as . Because iPSCs are developed from a patient's own cells, it was first thought that treatment using them would avoid any immunogenic responses. However, depending on methods used to generate such iPSCs, they may pose significant risks that limit their use. For example, using viruses to alter the cell's genome could promote cancer in the .

Methods previously developed to generate integration-free iPSCs were not easily and efficiently reproducible. Therefore, the UC San Diego researchers focused their approach on developing a self-replicating, RNA-based method (one that doesn't integrate into the DNA) with the ability to be retained and degraded in a controlled fashion, and that would only need to be introduced once into the cell.

Using a Venezuelan equine virus (VEE) with structural proteins deleted, but non-structural proteins still present, the scientists added four reprogramming factors (OCT4, KLF4, SOX2 with either c-MYC or GLIS1). They made a single transfection of the VEE replicative form (RF) RNA into newborn or adult human fibroblasts, connective tissue cells that provide a structural framework for many other tissues.

"This resulted in efficient generation of iPSCs with all the hallmarks of ," said principal investigator Steven Dowdy, PhD, professor in the UC San Diego Department of Cellular & Molecular Medicine. "The method is highly reproducible, efficient, non-integrative – and it works."

Dowdy added that it worked on both young and old human cells. He explained that this is important since – in order to be used therapeutically in fighting disease or to create disease models for research – iPSCs will need to be derived from the cells of middle-aged to old adults who are more prone to the diseases scientists are attempting to treat. In addition, reprogramming factors can be easily changed.

Explore further: How steroid hormones enable plants to grow

Related Stories

Induced pluripotent stem cells at risk for rejection

May 13, 2011

(PhysOrg.com) -- Biologists at UC San Diego have discovered that an important class of stem cells known as "induced pluripotent stem cells," or iPSCs, derived from an individual's own cells, could face immune ...

Take urine, add mouse cells and grow a new tooth

Jul 31, 2013

(Medical Xpress)—How to grow new teeth for people who are missing teeth because of old age, accidents, or disease has been an area of interest among researchers. Scientists in China say they have grown ...

Recommended for you

Researchers discover new strategy germs use to invade cells

15 hours ago

The hospital germ Pseudomonas aeruginosa wraps itself into the membrane of human cells: A team led by Dr. Thorsten Eierhoff and Junior Professor Dr. Winfried Römer from the Institute of Biology II, members of the Cluster ...

Progress in the fight against harmful fungi

15 hours ago

A group of researchers at the Max F. Perutz Laboratories has created one of the three world's largest gene libraries for the Candida glabrata yeast, which is harmful to humans. Molecular analysis of the Candida ...

How steroid hormones enable plants to grow

Aug 19, 2014

Plants can adapt extremely quickly to changes in their environment. Hormones, chemical messengers that are activated in direct response to light and temperature stimuli help them achieve this. Plant steroid ...

Surviving the attack of killer microbes

Aug 19, 2014

The ability to find food and avoid predation dictates whether most organisms live to spread their genes to the next generation or die trying. But for some species of microbe, a unique virus changes the rules ...

Histones and the mystery of cell proliferation

Aug 19, 2014

Before cells divide, they create so much genetic material that it must be wound onto spools before the two new cells can split apart. These spools are actually proteins called histones, and they must multiply ...

User comments : 0