San Diego, CA, United States
San Diego, CA, United States

Time filter

Source Type

Li G.,University of Sichuan | Xu F.,Sun Yat Sen University | Zhu J.,Institute for Engineering in Medicine | Krawczyk M.,Institute for Engineering in Medicine | And 28 more authors.
Journal of Biological Chemistry | Year: 2015

PAX6 is a master regulatory gene involved in neuronal cell fate specification. It also plays a critical role in early eye field and subsequent limbal stem cell (LSC) determination during eye development. Defects in Pax6 cause aniridia and LSC deficiency in humans and the Sey (Small eye) phenotype in mice (Massé, K., Bhamra, S., Eason, R., Dale, N., and Jones, E. A. (2007) Nature 449, 1058-1062). However, how PAX6 specifies LSC and corneal fates during eye development is not well understood. Here, we show that PAX6 is expressed in the primitive eye cup and later in corneal tissue progenitors in early embryonic development. In contrast, p63 expression commences after that of PAX6 in ocular adnexal and skin tissue progenitors and later in LSCs. Using an in vitro feeder-free culture system, we show that PAX6 knockdown in LSCs led to up-regulation of skin epidermis-specific keratins concomitant with differentiation to a skin fate. Using gene expression analysis, we identified the involvement of Notch, Wnt, and TGF-β signaling pathways in LSC fate determination. Thus, loss of PAX6 converts LSCs to epidermal stem cells, as demonstrated by a switch in the keratin gene expression profile and by the appearance of congenital dermoid tissue. © 2015, American Society for Biochemistry and Molecular Biology Inc. All rights reserved.


PubMed | Sun Yat Sen University, Institute for Engineering in Medicine, University of Sichuan, Harvard University and 2 more.
Type: Journal Article | Journal: The Journal of biological chemistry | Year: 2015

PAX6 is a master regulatory gene involved in neuronal cell fate specification. It also plays a critical role in early eye field and subsequent limbal stem cell (LSC) determination during eye development. Defects in Pax6 cause aniridia and LSC deficiency in humans and the Sey (Small eye) phenotype in mice (Mass, K., Bhamra, S., Eason, R., Dale, N., and Jones, E. A. (2007) Nature 449, 1058-1062). However, how PAX6 specifies LSC and corneal fates during eye development is not well understood. Here, we show that PAX6 is expressed in the primitive eye cup and later in corneal tissue progenitors in early embryonic development. In contrast, p63 expression commences after that of PAX6 in ocular adnexal and skin tissue progenitors and later in LSCs. Using an in vitro feeder-free culture system, we show that PAX6 knockdown in LSCs led to up-regulation of skin epidermis-specific keratins concomitant with differentiation to a skin fate. Using gene expression analysis, we identified the involvement of Notch, Wnt, and TGF- signaling pathways in LSC fate determination. Thus, loss of PAX6 converts LSCs to epidermal stem cells, as demonstrated by a switch in the keratin gene expression profile and by the appearance of congenital dermoid tissue.


Researchers at the University of Minnesota have made a major breakthrough that allows people to control a robotic arm using only their minds. The research has the potential to help millions of people who are paralyzed or have neurodegenerative diseases. The study is published online today in Scientific Reports, a Nature research journal. "This is the first time in the world that people can operate a robotic arm to reach and grasp objects in a complex 3D environment using only their thoughts without a brain implant," said Bin He, a University of Minnesota biomedical engineering professor and lead researcher on the study. "Just by imagining moving their arms, they were able to move the robotic arm." The noninvasive technique, called electroencephalography (EEG) based brain-computer interface, records weak electrical activity of the subjects' brain through a specialized, high-tech EEG cap fitted with 64 electrodes and converts the "thoughts" into action by advanced signal processing and machine learning. Eight healthy human subjects completed the experimental sessions of the study wearing the EEG cap. Subjects gradually learned to imagine moving their own arms without actually moving them to control a robotic arm in 3D space. They started from learning to control a virtual cursor on computer screen and then learned to control a robotic arm to reach and grasp objects in fixed locations on a table. Eventually, they were able to move the robotic arm to reach and grasp objects in random locations on a table and move objects from the table to a three-layer shelf by only thinking about these movements. All eight subjects could control a robotic arm to pick up objects in fixed locations with an average success rate above 80 percent and move objects from the table onto the shelf with an average success rate above 70 percent. "This is exciting as all subjects accomplished the tasks using a completely noninvasive technique. We see a big potential for this research to help people who are paralyzed or have neurodegenerative diseases to become more independent without a need for surgical implants," He said. The researchers said the brain-computer interface technology works due to the geography of the motor cortex--the area of the cerebrum that governs movement. When humans move, or think about a movement, neurons in the motor cortex produce tiny electric currents. Thinking about a different movement activates a new assortment of neurons, a phenomenon confirmed by cross-validation using functional MRI in He's previous study. Sorting out these assortments using advanced signal processing laid the groundwork for the brain-computer interface used by the University of Minnesota researchers, He said. The robotic arm research builds upon He's research published three years ago in which subjects were able to fly a small quadcopter using the noninvasive EEG technology. The research gained international media attention. "Three years ago, we weren't sure moving a more complex robotic arm to grasp and move objects using this brain-computer interface technology could even be achieved," He said. "We're happily surprised that it worked with a high success rate and in a group of people." He anticipates the next step of his research will be to further develop this brain-computer interface technology realizing a brain-controlled robotic prosthetic limb attached to a person's body or examine how this technology could work with someone who has had a stroke or is paralyzed. In addition to Professor He, who also serves as director of the University of Minnesota Institute for Engineering in Medicine, the research team includes biomedical engineering postdoctoral researcher Jianjun Meng (first author); biomedical engineering graduate student Bryan Baxter; Institute for Engineering in Medicine staff member Angeliki Bekyo; and biomedical engineering undergraduate students Shuying Zhang and Jaron Olsoe. The researchers are affiliated with the University of Minnesota College of Science and Engineering and the Medical School. The University of Minnesota study was funded by the National Science Foundation (NSF), the National Center for Complementary and Integrative Health, National Institute of Biomedical Imaging and Bioengineering, and National Institute of Neurological Disorders and Stroke of the National Institutes of Health (NIH), and the University of Minnesota's MnDRIVE (Minnesota's Discovery, Research and InnoVation Economy) Initiative funded by the Minnesota Legislature. To read the full research paper, entitled "Noninvasive Electroencephalogram Based Control of a Robotic Arm for Reach and Grasp Tasks," visit the Nature Scientific Reports website.


Microscopy image depicting fat cells (or adipocytes) after differentiation. The cells are stained with Oil Red O, which highlights lipid or fat droplets that accumulate with the fat cells. The metabolic studies described here indicated that fat cells produce these fatty acids, in part, from essential amino acids rather than sugar only. Credit: Metabolic Systems Biology lab, UC San Diego Jacobs School of Engineering Researchers at the University of California, San Diego report new insights into what nutrients fat cells metabolize to make fatty acids. The findings pave the way for understanding potential irregularities in fat cell metabolism that occur in patients with diabetes and obesity and could lead to new treatments for these conditions. The researchers published their findings online in the Nov. 16 issue of Nature Chemical Biology. "This study highlights how specific tissues in our bodies use particular nutrients. By understanding fat cell metabolism at the molecular level, we are laying the groundwork for further research to identify better drug targets for treating diabetes and obesity," said Christian Metallo, a bioengineering professor in the Jacobs School of Engineering at UC San Diego and senior author of the study. Metallo is affiliated with the Institute for Engineering in Medicine, the Moore's Cancer Center, and the CHO Systems Biology Center, all at UC San Diego. In the new study, researchers discovered that as fat cells develop, they change what types of nutrients they metabolize to produce fat and energy. Pre-adipocytes, which are precursors to fat cells, preferentially consume glucose, a simple sugar, to grow and make energy. But when pre-adipocytes become fat cells, researchers found that they metabolize not just glucose, but also branched-chain amino acids, a small set of the essential amino acids for humans. This finding is important because it shows that fat cells play an important role in regulating the body's levels of branched-chain amino acids—which are typically elevated in individuals with diabetes and obesity. "We've taken a step towards understanding why these amino acids are accumulating in the blood of diabetics and those suffering from obesity," said Courtney Green, a bioengineering Ph.D. student at UC San Diego and first author of the study. "The next step is to understand how and why this metabolic pathway becomes impaired in the fat cells of these individuals." Metallo and his team studied the metabolism of fat cells from the pre-adipocyte stage throughout the fat cell differentiation process. They induced pre-adipocytes to differentiate into fat cells and cultured the cells in media containing nutrients enriched with carbon-13 isotopes, a form of carbon atoms that are used as metabolic tracers in cells, animals, and people. Through this method, researchers were able to trace what carbon-based nutrients the cells metabolized and what they produced at different stages of the cell differentiation process. "We are curious about how different cells in our body, such as fat cells, consume and metabolize their surrounding nutrients. A better understanding of how these biochemical pathways are used by cells could help us find new approaches to treat diseases such as cancer or diabetes," said Metallo. More information: Courtney R Green et al. Branched-chain amino acid catabolism fuels adipocyte differentiation and lipogenesis, Nature Chemical Biology (2015). DOI: 10.1038/nchembio.1961


News Article | December 14, 2016
Site: www.rdmag.com

For the first time ever researchers at the University of Minnesota developed a robotic arm that can be controlled through the mind. Bin He, a University of Minnesota biomedical engineering professor and lead researcher on the study, explained this is a breakthrough that could help millions of people who are paralyzed or have neurodegenerative diseases. “This is the first time in the world that people can operate a robotic arm to reach and grasp objects in a complex 3D environment using only their thoughts without a brain implant,” he said in a statement. “Just by imagining moving their arms, they were able to move the robotic arm.” The arm is controlled using a noninvasive technique called electroencephalography (EEG), which is based on brain-computer interfaces. It records weak electrical activity of the subjects’ brain through a specialized, high-tech EEG cap fitted with 64 electrodes and converts the “thoughts” into action by advanced signal processing and machine learning. The researchers tested the invention on eight healthy human subjects. The participants gradually learned to imagine moving their own arm without actually moving them to control a robotic appendage in 3D space. The subjects improved from initially being able to control a virtual cursor on a computer screen to being able to control a robotic arm to reach and grasp objects in fixed locations on a table to a three-layer shelf by only thinking about the movements. Average success rates for the eight subjects in controlling the robotic arm and picking up objects in fixed locations was above 80 percent and the success rate in moving objects from the table onto the shelf was above 70 percent. “This is exciting as all subjects accomplished the tasks using a completely non-invasive technique,” He said. “We see a big potential for this research to help people who are paralyzed or have neurodegenerative diseases to become more independent without a need for surgical implants.” The brain-computer interface is able to work due to the geography of the motor cortex—the area of the cerebrum that governs movement. Neurons in the motor cortex produce tiny electric currents when humans move or think about a movement. When a human thinks about a different movement it activates a new assortment of neurons, a phenomenon confirmed by cross-validation using functional MRI in He’s previous study. According to He, sorting out these assortments using advanced signal processing laid the groundwork for the brain-computer interface used by University of Minnesota. The robotic arm is seen as an advancement of his previous research. “Three years ago, we weren’t sure moving a more complex robotic arm to grasp and move objects using this brain-computer interface technology could even be achieved,” He said. “We’re happily surprised that it worked with a high success rate and in a group of people.” He said the next step would be to further develop the brain-computer interface technology realizing a brain-controlled robotic prosthetic limb attached to a person’s body or examine how the technology could work with someone who has had a stroke or is paralyzed. In addition to He, who also serves as director of the University of Minnesota Institute for Engineering in Medicine, the research team includes biomedical engineering postdoctoral researcher Jianjun Meng (first author); biomedical engineering graduate student Bryan Baxter; Institute for Engineering in Medicine staff member Angeliki Bekyo; and biomedical engineering undergraduate students Shuying Zhang and Jaron Olsoe. The researchers are affiliated with the University of Minnesota College of Science and Engineering and the Medical School. The study was published in Scientific Reports.

Loading Institute for Engineering in Medicine collaborators
Loading Institute for Engineering in Medicine collaborators