Tufts doctoral student Sarah Sundelacruz, Professor of Biology Michael Levin, and Chair of Biomedical Engineering David L. Kaplan (corresponding author) published their paper "Membrane Potential Controls Adipogenic and Osteogenic Differentiation of Mesenchymal Stem Cells" in the November 17, 2008, issue of PLoS ONE (http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0003737).
"We have found that voltage changes act as a signal to delay or accelerate the decision of a stem cell to drop out of a stem state and differentiate into a specific cell type. This discovery gives scientists in regenerative medicine a new set of control knobs to use in ongoing efforts to shape the behavior of adult stem cells," said Levin. "In addition, by uncovering a new mechanism by which these cells are controlled in the human body, this research suggests potential future diagnostic applications."
Harnessing the potential of stem cells for applications such as wound healing and tissue regeneration is a tantalizing yet daunting task. Although many studies indicate that electrophysiology plays a crucial role in cell proliferation and differentiation, its functional role in stem cell biology is poorly understood.
The Tufts researchers studied the changes in membrane potential (voltage across the membrane) shown by human mesenchymal stem cells (hMSCs) obtained from donor bone marrow as the hMSCs were differentiating into fat and bone cells. They found that hyperpolarization (increased difference between the voltage in the interior and exterior of a cell) was characteristic of differentiated cells compared with undifferentiated cells and that hMSCs show different membrane potential profiles during bone vs. fat differentiation.
To determine whether hyperpolarization was functionally required for differentiation, the scientists depolarized the hMSCs by exposing them either to high levels of extracellular potassium ions or to ouabain, a compound that blocks the transfer of ions in and out of cells. Both treatments disrupted the normal increase in negative voltage that occurs during differentiation and suppressed fat and bone cell differentiation markers.
In contrast, treatment with hyperpolarizing reagents up-regulated bone cell markers – indicating that voltage changes are not merely permissive for differentiation but can act as an instructive signal to either induce or inhibit differentiation.
More study is needed to determine whether hyperpolarization also determines which specific type of cell stem cells will differentiate into, according to the Tufts researchers.
Funding for the study came from the National Science Foundation through the Graduate Research Fellowship Program, the National Institutes of Health through the Tissue Engineering Resource Center, the National Highway Traffic Safety Administration and the U.S. Defense Advanced Research Projects Agency.
Tufts University, located on three Massachusetts campuses in Boston, Medford/Somerville, and Grafton, and in Talloires, France, is recognized among the premier research universities in the United States. Tufts enjoys a global reputation for academic excellence and for the preparation of students as leaders in a wide range of professions. A growing number of innovative teaching and research initiatives span all Tufts campuses, and collaboration among the faculty and students in the undergraduate, graduate and professional programs across the university's schools is widely encouraged.
Kim Thurler | Newswise Science News
Rainbow colors reveal cell history: Uncovering β-cell heterogeneity
22.09.2017 | DFG-Forschungszentrum für Regenerative Therapien TU Dresden
The pyrenoid is a carbon-fixing liquid droplet
22.09.2017 | Max-Planck-Institut für Biochemie
Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.
A warming planet
Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.
The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...
Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...
Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!
When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...
For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.
Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...
19.09.2017 | Event News
12.09.2017 | Event News
06.09.2017 | Event News
22.09.2017 | Life Sciences
22.09.2017 | Medical Engineering
22.09.2017 | Physics and Astronomy