Glial biology; ion channels and synaptic function; systems neuroscience and vision
Vladimir Parpura, M.D., Ph.D holds both a medical degree, awarded from the University of Zagreb in Croatia in 1989, and a doctorate, received in Neuroscience and Zoology from Iowa State University in 1993. He has held faculty appointments at the Department of Zoology and Genetics, Iowa State University and the Department of Cell Biology and Neuroscience, University of California Riverside. He is presently a Professor in the Department of Neurobiology, University of Alabama Birmingham and President-Elect (2-year term) for the American Society for Neurochemistry; to be President 2017-2019. Elected as a Member of Academia Europaea (MAE) in 2012.
His current research includes: i) studying the modulation of calcium-dependent glutamate release from astrocytes in health and disease; ii) visualization of vesicular/receptor trafficking; iii) examination of the nature and energetics of interactions between exocytotic proteins using single molecule detection approaches; iv) development of scaffolds and dispersible materials, most notably modified carbon nanotubes, which can be used in repair after brain injury and v) bio-mimetic micro-robotics. He has been interfacing neuroscience with nanoscience/nanotechnology, synthetic biology and biomedical engineering.
Nearly all of the suggested activities for astrocytes are based on observed correlations, and many of these have been made on cultured cells, whose properties may differ from those in vivo. As an alternative approach to understanding astrocyte function, our group is studying their cell-specific transcription and the role of the GFAP protein. GFAP was selected for study because its gene is expressed fairly strongly, and almost exclusively, in astrocytes. Expression of the gene is also turned on about the same time as astrocytes mature, and its activity increases dramatically following almost any CNS injury. Thus, study of GFAP transcription should yield insights into mechanisms governing development, reaction to injury, and cell specificity. The interesting regulation of the GFAP gene, and the fact that astrocytes have elaborated their own specific intermediate filament protein, predict an important role for GFAP in these cells. We have discovered two such roles for the protein. We have found that the absence of GFAP renders mice hypersensitive to traumatic spinal cord injury, revealing a novel role for GFAP in structural support. We have also discovered that mutations within the coding sequence of the GFAP gene are responsible for many cases of Alexander disease, a rare but often fatal neurodegenerative disorder of humans.
Glial cells were long considered to serve merely as the supporting cast and scenery against which the starring neuronal roles would be played out. Relatively recent evidence, however, indicates that glial cells are intimately involved in many of the brain's functions, including its computational power. Our research has been instrumental in demonstrating a novel functional role for glial cells. Hence, astrocytes, a sub-type of glial cell, can exocytotically release the neurotransmitter glutamate and, in turn, that glutamate released from astrocytes can signal to adjacent neurons. Indeed, by releasing glutamate, astrocytes can modulate synaptic transmission in response to experimental stimuli. Since intracellular calcium ion levels critical for secretion from astrocytes are within the physiological range, this release of glutamate from astrocytes could represent an additional site for modulation of synaptic transmission and integration in the CNS.
A wide repertoire of molecular biological techniques is used in our studies. These include screening of gene libraries, subcloning, DNA sequencing, Southern, northern and western blotting, synthesis of reporter genes and transgenes, site-directed mutagenesis, in vitro transcription and translation, primer extension, riboprobe protection, culture of cell lines and primary cells, transient and stable transfections, DNA footprinting, gel mobility shift assays, polymerase chain reaction (PCR) and reverse-transcription PCR (RT-PCR), fluorescent double-label immunocytochemistry, protein purification and mass spectrometry.
- Parpura, V., Schousboe, A., Verkhratsky, A. (Eds.) Glutamate and ATP at interface of metabolism and signaling in the brain (Advances in Neurobiology Vol. 11). Springer, New York, NY (2014) (Nov 14, 2014; 261 pp) DOI 10.1007/978-3-319-08894-5
- Parpura, V., Verkhratsky, A. (Eds.) Pathological potential of neuroglia: Possible new targets for medical intervention. Springer, New York, NY (2014) (Sept 28, 2014; 541 pp) ISBN-13: 978-1493909735
- Verkhratsky, A., Parpura, V. Physiology of Astroglia: Channels, Receptors, Transporters, Ion Signaling and Gliotransmission. In: Colloquium Series on Neuroglia in biology and medicine: From physiology to disease (Verkhratsky, A., Parpura, V., Eds). Morgan & Claypool Publishers, Colloquium Digital Library of Life Sciences; DOI: 10.4199/C00123ED1V01Y201501NGL004 (March 2015; 174 pp)
- William Lee
- Wei Liu
- Randy F. Stout, Jr.
- Reno C. Reyes
- Vladimir Grubisic
- Roberto Gomez-Suarez
- Josheua J. Samuelson
- J. Robert Grammer
M.D., University of Zagreb
Ph.D., Neuroscience and Zoology, Iowa State University