Song Li, Ph.D.

Professor Song Li and his research team have shown that physical cues can replace certain chemicals when inducing mature cells back to a pluripotent stage, capable of becoming any cell type in the body.

Bioengineers at the University of California, Berkeley, have shown that physical cues can replace certain chemicals when nudging mature cells back to a pluripotent stage, capable of becoming any cell type in the body.

The researchers grew fibroblasts – cells taken from human skin and mouse ears – on surfaces with parallel grooves measuring 10 micrometers wide and 3 micrometers high. After two weeks of culture in a special cocktail used to reprogram mature cells, the researchers found a four-fold increase in the number of cells that reverted back to an embryonic-like state compared with cells grown on a flat surface. Growing cells in scaffolds of nanofibers aligned in parallel had similar effects.

The study, published online today (Sunday, Oct. 20) in the journal Nature Materials, could significantly enhance the process of reprogramming adult cells into embryonic-like stem cells that can differentiate, or develop, into any type of tissue that makes up our bodies.

The 2012 Nobel Prize in Physiology or Medicine was awarded to scientists who discovered that it was possible to reprogram cells using biochemical compounds and proteins that regulate gene expression. These induced pluripotent stem cells have since become a research mainstay in regenerative medicine, disease modeling and drug screening.

“Our study demonstrates for the first time that the physical features of biomaterials can replace some of these biochemical factors and regulate the memory of a cell’s identity,” said study principal investigator Song Li, UC Berkeley professor of bioengineering. “We show that biophysical signals can be converted into intracellular chemical signals that coax cells to change.”

Professor Song Li is part of the bioengineering faculty at UC Berkeley and specializes in biomechanics and cell & tissue engineering.  He was interviewed to share his experiences and offer advice to current bioengineering students.  He recommends all bioengineering students supplement their engineering education with hands-on research in order to develop a strong set of technical skills that will be attractive to future employers.  He tells students to stay connected to friends and alumni who have graduated from Berkeley and/or have been through similar experiences.  All in all, he believes that bioengineering has very promising life-changing innovations for the future.

One of the top suspects behind killer vascular diseases is the victim of mistaken identity, according to researchers from the University of California, Berkeley, who used genetic tracing to help hunt down the real culprit.

The guilty party is not the smooth muscle cells within blood vessel walls, which for decades was thought to combine with cholesterol and fat that can clog arteries. Blocked vessels can eventually lead to heart attacks and strokes, which account for one in three deaths in the United States.

Instead, a previously unknown type of stem cell — a multipotent vascular stem cell — is to blame, and it should now be the focus in the search for new treatments, the scientists report in a new study appearing June 6 in the journal Nature Communications.

“For the first time, we are showing evidence that vascular diseases are actually a kind of stem cell disease,” said principal investigator Song Li, professor of bioengineering and a researcher at the Berkeley Stem Cell Center. “This work should revolutionize therapies for vascular diseases because we now know that stem cells rather than smooth muscle cells are the correct therapeutic target.”

The finding that a stem cell population contributes to artery-hardening diseases, such as atherosclerosis, provides a promising new direction for future research, the study authors said.