Magnetogenetics edit
Magnetogenetics is a relatively new field that is related to optogenetics, which is the manipulation of cell behavior using light. Magnetogenetics instead use magnetic stimuli to manipulate cell behavior, which can be less invasive in sensitive tissues, like neural tissue, since magnetogenetic methods do not require invasive surgery.[1] This field developed from combining principles observed in various magnetotactic bacteria with optogenetic techniques,[2] helping researchers manipulate cell behaviors and gene expression in the presence of magnetic fields. There are multiple tissues in the body that can be combined with magnetic proteins or with magnetosomes from bacteria, including brain tissue, tumors, and others. The activation of the magnetic compounds can cause effects on the organism via either mechanical or thermal effects.
Magnetotactic Bacteria edit
Magnetotactic bacteria (MTB), which are utilized for the applications of magnetogenetics, are typically found in aquatic environments and uniquely contain an organelle called a magnetosome. This membraned organelle contains a microscopic crystalline structure of a magnetic iron mineral. Magnetosomes are organized in long, chains which assists in the cells motile ability to align and swim parallel to magnetic fields, known as magnetotaxis[3]. These orientations caused by the magnetosome can have various implications on eukaryotic cells that they inhabit. Two magnetotactc bacteria commonly used in laboratory settings are Magnetospirillum megneticum (AMB-1) and Magnetosprillium gryphiswaldense (MSR-1) due their ease in cultivation and ability to produce the compounds necessary for crystalline structure formation. To synthesize the magentosomes first the cell invaginates it outer membrane to create a vesicle and allows for the magnetosome proteins to be sorted in the vesicle membrane. Iron is the imported into the magnetosome as crystal-coated strucutres, and the magentosomes aggregate as a chain[4].
Mechanisms edit
Brain stimulation edit
Magnetogenetic techniques involve first fusing TRPV class receptors, which are selective calcium transporters, with a paramagnetic protein (typically ferratin).[5][6] These paramagnetic proteins, which typically contain iron or have iron-containing cofactors, are then stimulated with a magnetic field exerted on the brain. The next steps in the activation of the neurons is still unclear, but it is thought that the ion channels are activated and opened either by a mechanical force exerted by the paramagnetic proteins,[2] or by the heating of these proteins in response to the stimulation by the magnetic field.
Cancer edit
Magnetosomes can be engulfed by certain eukaryotic cells and this allows these eukaryotic cells to be manipulated in specific ways. One such application is using Magnetic resonance imaging (MRI). The paramagnetic particles contained within the magnetosomes in these bacteria can be used to positive or negative contrast agents.[7] Magnetotactic bacteria have been found to be preferentially taken up by tumor cells allowing for these tumors to be imaged in an MRI.[8]
Magnetic hyperthermia is another potential application of the magnetosomes produced by these bacteria. Hyperthermia therapy is a current clinical technique used to treat cancers; however, magnetic hyperthermia could offer a more specific targeted cancer treatment.[8]
References edit
- ^ Nimpf, Simon; Keays, David A (2017-06-14). "Is magnetogenetics the new optogenetics?". The EMBO Journal. 36 (12): 1643–1646. doi:10.15252/embj.201797177. ISSN 0261-4189. PMC PMCPMC5470037. PMID 28536151.
{{cite journal}}: Check|pmc=value (help) - ^ a b Vogt, Nina (2016-10-31). "Biophysics: Unraveling magnetogenetics". Nature Methods. 13: 900–901. doi:10.1038/nmeth.4060. ISSN 1548-7105.
- ^ Bazylinski, Dennis A.; Lefèvre, Christopher T. (2013-09-01). "Ecology, Diversity, and Evolution of Magnetotactic Bacteria". Microbiol. Mol. Biol. Rev. 77 (3): 497–526. doi:10.1128/MMBR.00021-13. ISSN 1092-2172. PMID 24006473.
- ^ Dirk Schüler; Uebe, René (2016-10). "Magnetosome biogenesis in magnetotactic bacteria". Nature Reviews Microbiology. 14 (10): 621–637. doi:10.1038/nrmicro.2016.99. ISSN 1740-1534.
{{cite journal}}: Check date values in:|date=(help) - ^ Güler, Ali D.; Deppmann, Christopher D.; Patel, Manoj K.; Kucenas, Sarah; Beenhakker, Mark P.; Spano, Anthony J.; Gaykema, Ronald P.; Grippo, Ryan M.; Purohit, Aarti M. (2016-05). "Genetically targeted magnetic control of the nervous system". Nature Neuroscience. 19 (5): 756–761. doi:10.1038/nn.4265. ISSN 1546-1726.
{{cite journal}}: Check date values in:|date=(help) - ^ Long, Xiaoyang; Ye, Jing; Zhao, Di; Zhang, Sheng-Jia (2015-12-01). "Magnetogenetics: remote non-invasive magnetic activation of neuronal activity with a magnetoreceptor". Science Bulletin. 60 (24): 2107–2119. doi:10.1007/s11434-015-0902-0. ISSN 2095-9281. PMC 4692962. PMID 26740890.
{{cite journal}}: CS1 maint: PMC format (link) - ^ Alphandéry, Edouard (2014-03-11). "Applications of Magnetosomes Synthesized by Magnetotactic Bacteria in Medicine". Frontiers in Bioengineering and Biotechnology. 2. doi:10.3389/fbioe.2014.00005. ISSN 2296-4185. PMC PMCPMC4126476. PMID 25152880.
{{cite journal}}: Check|pmc=value (help)CS1 maint: unflagged free DOI (link) - ^ a b Benoit, M. R.; Mayer, D.; Barak, Y.; Chen, I. Y.; Hu, W.; Cheng, Z.; Wang, S. X.; Spielman, D. M.; Gambhir, S. S. (2009-08-11). "Visualizing Implanted Tumors in Mice with Magnetic Resonance Imaging Using Magnetotactic Bacteria". Clinical Cancer Research. 15 (16): 5170–5177. doi:10.1158/1078-0432.ccr-08-3206. ISSN 1078-0432.