Cell migration is a central process in the development and maintenance of multicellular organisms. Tissue formation during embryonic development, wound healing and immune responses all require the orchestrated movement of cells in particular directions to specific locations. Cells often migrate in response to specific external signals, including chemical signals and mechanical signals.[1] Errors during this process have serious consequences, including intellectual disability, vascular disease, tumor formation and metastasis.[2] [3] An understanding of the mechanism by which cells migrate may lead to the development of novel therapeutic strategies for controlling, for example, invasive tumour cells.
Due to the highly viscous environment (low Reynolds number), cells need to continuously produce forces in order to move. Cells achieve active movement by very different mechanisms. Many less complex prokaryotic organisms (and sperm cells) use flagella or cilia to propel themselves. Eukaryotic cell migration typically is far more complex and can consist of combinations of different migration mechanisms. It generally involves drastic changes in cell shape which are driven by the cytoskeleton. Two very distinct migration scenarios are crawling motion (most commonly studied) and blebbing motility.[4][5] A paradigmatic example of crawling motion is the case of fish epidermal keratocytes, which have been extensively used in research and teaching.[6]
Cell migration studies
editThe migration of cultured cells attached to a surface or in 3D is commonly studied using microscopy.[7][8][5] As cell movement is very slow, a few μm/minute, time-lapse microscopy videos are recorded of the migrating cells to speed up the movement. Such videos (Figure 1) reveal that the leading cell front is very active, with a characteristic behavior of successive contractions and expansions. It is generally accepted that the leading front is the main motor that pulls the cell forward.
Common features
editThe processes underlying mammalian cell migration are believed to be consistent with those of (non-spermatozooic) locomotion.[9] Observations in common include:
- cytoplasmic displacement at leading edge (front)
- laminar removal of dorsally-accumulated debris toward trailing edge (back)
The latter feature is most easily observed when aggregates of a surface molecule are cross-linked with a fluorescent antibody or when small beads become artificially bound to the front of the cell.[10]
Other eukaryotic cells are observed to migrate similarly. The amoeba Dictyostelium discoideum is useful to researchers because they consistently exhibit chemotaxis in response to cyclic AMP; they move more quickly than cultured mammalian cells; and they have a haploid genome that simplifies the process of connecting a particular gene product with its effect on cellular behaviour.[11]
Molecular processes of migration
editThere are two main theories for how the cell advances its front edge: the cytoskeletal model and membrane flow model. It is possible that both underlying processes contribute to cell extension.
Cytoskeletal model (A)
editLeading edge
editExperimentation has shown that there is rapid actin polymerisation at the cell's front edge.[12] This observation has led to the hypothesis that formation of actin filaments "push" the leading edge forward and is the main motile force for advancing the cell's front edge.[13][14] In addition, cytoskeletal elements are able to interact extensively and intimately with a cell's plasma membrane.[15]
Trailing edge
editOther cytoskeletal components (like microtubules) have important functions in cell migration. It has been found that microtubules act as "struts" that counteract the contractile forces that are needed for trailing edge retraction during cell movement. When microtubules in the trailing edge of cell are dynamic, they are able to remodel to allow retraction. When dynamics are suppressed, microtubules cannot remodel and, therefore, oppose the contractile forces.[16] The morphology of cells with suppressed microtubule dynamics indicate that cells can extend the front edge (polarized in the direction of movement), but have difficulty retracting their trailing edge.[17] On the other hand, high drug concentrations, or microtubule mutations that depolymerize the microtubules, can restore cell migration but there is a loss of directionality. It can be concluded that microtubules act both to restrain cell movement and to establish directionality.
Membrane flow model (B)
editThe leading edge at the front of a migrating cell is also the site at which membrane from internal membrane pools is returned to the cell surface at the end of the endocytic cycle.[18][19] This suggests that extension of the leading edge occurs primarily by addition of membrane at the front of the cell. If so, the actin filaments that form there might stabilize the added membrane so that a structured extension, or lamella, is formed — rather than a bubble-like structure (or bleb) at its front.[20] For a cell to move, it is necessary to bring a fresh supply of "feet" (proteins called integrins, which attach a cell to the surface on which it is crawling) to the front. It is likely that these feet are endocytosed [21] toward the rear of the cell and brought to the cell's front by exocytosis, to be reused to form new attachments to the substrate.
In the case of Dictyostelium amoebae, three conditional temperature sensitive mutants which affect membrane recycling block cell migration at the restrictive (higher) temperature;[22][23][24] they provide additional support for the importance of the endocytic cycle in cell migration. Furthermore, these amoebae move quite quickly — about one cell length in ~5 mins. If they are regarded as cylindrical (which is roughly true whilst chemotaxing), this would require them to recycle the equivalent of one cell surface area each 5 mins, which is approximately what is measured.[25]
Mechanistic basis of amoeboid migration
editAdhesive crawling is not the only migration mode exhibited by eukaryotic cells. Importantly, several cell types — Dictyostelium amoebae, neutrophils, metastatic cancer cells and macrophages — have been found to be capable of adhesion-independent migration. Historically, the physicist E. M. Purcell theorized (in 1977) that under conditions of low Reynolds number fluid dynamics, which apply at the cellular scale, rearward surface flow could provide a mechanism for microscopic objects to swim forward.[27] After some decades, experimental support for this model of cell movement was provided when it was discovered (in 2010) that amoeboid cells and neutrophils are both able to chemotax towards a chemo-attractant source whilst suspended in an isodense medium.[28] It was subsequently shown, using optogenetics, that cells migrating in an amoeboid fashion without adhesions exhibit plasma membrane flow towards the cell rear that may propel cells by exerting tangential forces on the surrounding fluid.[26][29] Polarized trafficking of membrane-containing vesicles from the rear to the front of the cell helps maintain cell size.[26] Rearward membrane flow was also observed in Dictyostelium discoideum cells.[30] These observations provide strong support for models of cell movement which depend on a rearward cell surface membrane flow (Model B, above). The migration of supracellular clusters has also been found to be supported by a similar mechanism of rearward surface flow.[31]
Collective biomechanical and molecular mechanism of cell motion
editBased on some mathematical models, recent studies hypothesize a novel biological model for collective biomechanical and molecular mechanism of cell motion.[32] It is proposed that microdomains weave the texture of cytoskeleton and their interactions mark the location for formation of new adhesion sites. According to this model, microdomain signaling dynamics organizes cytoskeleton and its interaction with substratum. As microdomains trigger and maintain active polymerization of actin filaments, their propagation and zigzagging motion on the membrane generate a highly interlinked network of curved or linear filaments oriented at a wide spectrum of angles to the cell boundary. It is also proposed that microdomain interaction marks the formation of new focal adhesion sites at the cell periphery. Myosin interaction with the actin network then generate membrane retraction/ruffling, retrograde flow, and contractile forces for forward motion. Finally, continuous application of stress on the old focal adhesion sites could result in the calcium-induced calpain activation, and consequently the detachment of focal adhesions which completes the cycle.
Polarity in migrating cells
editMigrating cells have a polarity—a front and a back. Without it, they would move in all directions at once, i.e. spread. How this polarity is formulated at a molecular level inside a cell is unknown. In a cell that is meandering in a random way, the front can easily give way to become passive as some other region, or regions, of the cell form(s) a new front. In chemotaxing cells, the stability of the front appears enhanced as the cell advances toward a higher concentration of the stimulating chemical. From biophysical perspective, polarity was explained in terms of a gradient in inner membrane surface charge between front regions and rear edges of the cell.[33] This polarity is reflected at a molecular level by a restriction of certain molecules to particular regions of the inner cell surface. Thus, the phospholipid PIP3 and activated Ras, Rac, and CDC42 are found at the front of the cell, whereas Rho GTPase and PTEN are found toward the rear.[34][35][36][37]
It is believed that filamentous actins and microtubules are important for establishing and maintaining a cell's polarity.[38] Drugs that destroy actin filaments have multiple and complex effects, reflecting the wide role that these filaments play in many cell processes. It may be that, as part of the locomotory process, membrane vesicles are transported along these filaments to the cell's front. In chemotaxing cells, the increased persistence of migration toward the target may result from an increased stability of the arrangement of the filamentous structures inside the cell and determine its polarity. In turn, these filamentous structures may be arranged inside the cell according to how molecules like PIP3 and PTEN are arranged on the inner cell membrane. And where these are located appears in turn to be determined by the chemoattractant signals as these impinge on specific receptors on the cell's outer surface.
Although microtubules have been known to influence cell migration for many years, the mechanism by which they do so has remained controversial. On a planar surface, microtubules are not needed for the movement, but they are required to provide directionality to cell movement and efficient protrusion of the leading edge.[17][39] When present, microtubules retard cell movement when their dynamics are suppressed by drug treatment or by tubulin mutations.[17]
Inverse problems in the context of cell motility
editAn area of research called inverse problems in cell motility has been established. [40][41][32] This approach is based on the idea that behavioral or shape changes of a cell bear information about the underlying mechanisms that generate these changes. Reading cell motion, namely, understanding the underlying biophysical and mechanochemical processes, is of paramount importance.[42] The mathematical models developed in these works determine some physical features and material properties of the cells locally through analysis of live cell image sequences and uses this information to make further inferences about the molecular structures, dynamics, and processes within the cells, such as the actin network, microdomains, chemotaxis, adhesion, and retrograde flow.
See also
editReferences
edit- ^ Mak M, Spill F, Kamm RD, Zaman MH (February 2016). "Single-Cell Migration in Complex Microenvironments: Mechanics and Signaling Dynamics". Journal of Biomechanical Engineering. 138 (2): 021004. doi:10.1115/1.4032188. PMC 4844084. PMID 26639083.
- ^ Swaney K, Huang CH, Devreotes PN (2010). "Eukaryotic Chemotaxis: A Network of Signaling Pathways Controls Motility, Directional Sensing, and Polarity". Annual Review of Biophysics. 39: 265–289. doi:10.1146/annurev.biophys.093008.131228. PMC 4364543. PMID 20192768.
- ^ Zhan H, Bhattacharya S, Cai H, Iglesias PA, Huang CH, Devreotes PN (September 2020). "An excitable Ras/PI3K/ERK signaling network controls migration and oncogenic transformation in epithelial cells". Developmental Cell. 54 (5): 608–623. doi:10.1016/j.devcel.2020.08.001. PMC 7505206. PMID 32877650.
- ^ Huber F, Schnauß J, Rönicke S, Rauch P, Müller K, Fütterer C, et al. (January 2013). "Emergent complexity of the cytoskeleton: from single filaments to tissue". Advances in Physics. 62 (1): 1–112. Bibcode:2013AdPhy..62....1H. doi:10.1080/00018732.2013.771509. PMC 3985726. PMID 24748680. online
- ^ a b Pebworth MP, Cismas SA, Asuri P (2014). "A novel 2.5D culture platform to investigate the role of stiffness gradients on adhesion-independent cell migration". PLOS ONE. 9 (10): e110453. Bibcode:2014PLoSO...9k0453P. doi:10.1371/journal.pone.0110453. PMC 4195729. PMID 25310593.
- ^ Prieto D, Aparicio G, Sotelo-Silveira JR (November 2017). "Cell migration analysis: A low-cost laboratory experiment for cell and developmental biology courses using keratocytes from fish scales". Biochemistry and Molecular Biology Education. 45 (6): 475–482. doi:10.1002/bmb.21071. PMID 28627731.
- ^ Dormann D, Weijer CJ (August 2006). "Imaging of cell migration". The EMBO Journal. 25 (15): 3480–3493. doi:10.1038/sj.emboj.7601227. PMC 1538568. PMID 16900100.
- ^ Shih W, Yamada S (December 2011). "Live-cell imaging of migrating cells expressing fluorescently-tagged proteins in a three-dimensional matrix". Journal of Visualized Experiments (58). doi:10.3791/3589. PMC 3369670. PMID 22215133.
- ^ "What is Cell Migration?". Cell Migration Gateway. Cell Migration Consortium. Archived from the original on 22 October 2014. Retrieved 24 March 2013.
- ^ Abercrombie M, Heaysman JE, Pegrum SM (October 1970). "The locomotion of fibroblasts in culture. 3. Movements of particles on the dorsal surface of the leading lamella". Experimental Cell Research. 62 (2): 389–398. doi:10.1016/0014-4827(70)90570-7. PMID 5531377.
- ^ Willard SS, Devreotes PN (September 2006). "Signaling pathways mediating chemotaxis in the social amoeba, Dictyostelium discoideum". European Journal of Cell Biology. 85 (9–10): 897–904. doi:10.1016/j.ejcb.2006.06.003. PMID 16962888.
- ^ Wang YL (August 1985). "Exchange of actin subunits at the leading edge of living fibroblasts: possible role of treadmilling". The Journal of Cell Biology. 101 (2): 597–602. doi:10.1083/jcb.101.2.597. PMC 2113673. PMID 4040521.
- ^ Mitchison TJ, Cramer LP (February 1996). "Actin-based cell motility and cell locomotion". Cell. 84 (3): 371–379. doi:10.1016/S0092-8674(00)81281-7. PMID 8608590. S2CID 982415.
- ^ Pollard TD, Borisy GG (February 2003). "Cellular motility driven by assembly and disassembly of actin filaments". Cell. 112 (4): 453–465. doi:10.1016/S0092-8674(03)00120-X. PMID 12600310. S2CID 6887118.
- ^ Doherty GJ, McMahon HT (2008). "Mediation, modulation, and consequences of membrane-cytoskeleton interactions". Annual Review of Biophysics. 37: 65–95. doi:10.1146/annurev.biophys.37.032807.125912. PMID 18573073.
- ^ Yang H, Ganguly A, Cabral F (October 2010). "Inhibition of cell migration and cell division correlates with distinct effects of microtubule inhibiting drugs". The Journal of Biological Chemistry. 285 (42): 32242–32250. doi:10.1074/jbc.M110.160820. PMC 2952225. PMID 20696757.
- ^ a b c Ganguly A, Yang H, Sharma R, Patel KD, Cabral F (December 2012). "The role of microtubules and their dynamics in cell migration". The Journal of Biological Chemistry. 287 (52): 43359–43369. doi:10.1074/jbc.M112.423905. PMC 3527923. PMID 23135278.
- ^ Bretscher MS (January 1983). "Distribution of receptors for transferrin and low density lipoprotein on the surface of giant HeLa cells". Proceedings of the National Academy of Sciences of the United States of America. 80 (2): 454–458. Bibcode:1983PNAS...80..454B. doi:10.1073/pnas.80.2.454. PMC 393396. PMID 6300844.
- ^ Hopkins CR, Gibson A, Shipman M, Strickland DK, Trowbridge IS (June 1994). "In migrating fibroblasts, recycling receptors are concentrated in narrow tubules in the pericentriolar area, and then routed to the plasma membrane of the leading lamella". The Journal of Cell Biology. 125 (6): 1265–1274. doi:10.1083/jcb.125.6.1265. PMC 2290921. PMID 7515888.
- ^ Bretscher MS (November 1996). "Getting membrane flow and the cytoskeleton to cooperate in moving cells". Cell. 87 (4): 601–606. doi:10.1016/S0092-8674(00)81380-X. PMID 8929529. S2CID 14776455.
- ^ Bretscher MS (February 1992). "Circulating integrins: alpha 5 beta 1, alpha 6 beta 4 and Mac-1, but not alpha 3 beta 1, alpha 4 beta 1 or LFA-1". The EMBO Journal. 11 (2): 405–410. doi:10.1002/j.1460-2075.1992.tb05068.x. PMC 556468. PMID 1531629.
- ^ Thompson CR, Bretscher MS (September 2002). "Cell polarity and locomotion, as well as endocytosis, depend on NSF". Development. 129 (18): 4185–4192. doi:10.1242/dev.129.18.4185. PMID 12183371.
- ^ Bretscher MS, Clotworthy M (August 2007). "Using single loxP sites to enhance homologous recombination: ts mutants in Sec1 of Dictyostelium discoideum". PLOS ONE. 2 (8): e724. Bibcode:2007PLoSO...2..724B. doi:10.1371/journal.pone.0000724. PMC 1933600. PMID 17684569.
- ^ Zanchi R, Howard G, Bretscher MS, Kay RR (October 2010). "The exocytic gene secA is required for Dictyostelium cell motility and osmoregulation". Journal of Cell Science. 123 (Pt 19): 3226–3234. doi:10.1242/jcs.072876. PMC 2939799. PMID 20807800.
- ^ Aguado-Velasco C, Bretscher MS (December 1999). "Circulation of the plasma membrane in Dictyostelium". Molecular Biology of the Cell. 10 (12): 4419–4427. doi:10.1091/mbc.10.12.4419. PMC 25767. PMID 10588667.
- ^ a b c O'Neill PR, Castillo-Badillo JA, Meshik X, Kalyanaraman V, Melgarejo K, Gautam N (July 2018). "Membrane Flow Drives an Adhesion-Independent Amoeboid Cell Migration Mode". Developmental Cell. 46 (1): 9–22.e4. doi:10.1016/j.devcel.2018.05.029. PMC 6048972. PMID 29937389.
- ^ Purcell EM (1977). "Life at Low Reynolds Number". American Journal of Physics. 45 (3): 3–11. Bibcode:1977AmJPh..45....3P. doi:10.1119/1.10903. hdl:2433/226838.
- ^ Barry NP, Bretscher MS (June 2010). "Dictyostelium amoebae and neutrophils can swim". Proceedings of the National Academy of Sciences of the United States of America. 107 (25): 11376–11380. Bibcode:2010PNAS..10711376B. doi:10.1073/pnas.1006327107. PMC 2895083. PMID 20534502.
- ^ Bell GR, Collins SR (July 2018). ""Rho"ing a Cellular Boat with Rearward Membrane Flow". Developmental Cell. 46 (1): 1–3. doi:10.1016/j.devcel.2018.06.008. PMID 29974859.
- ^ Tanaka M, Kikuchi T, Uno H, Okita K, Kitanishi-Yumura T, Yumura S (October 2017). "Turnover and flow of the cell membrane for cell migration". Scientific Reports. 7 (1): 12970. Bibcode:2017NatSR...712970T. doi:10.1038/s41598-017-13438-5. PMC 5636814. PMID 29021607.
- ^ Shellard A, Szabó A, Trepat X, Mayor R (October 2018). "Supracellular contraction at the rear of neural crest cell groups drives collective chemotaxis". Science. 362 (6412): 339–343. Bibcode:2018Sci...362..339S. doi:10.1126/science.aau3301. PMC 6218007. PMID 30337409.
- ^ a b c Coskun H, Coskun H (March 2011). "Cell physician: reading cell motion: a mathematical diagnostic technique through analysis of single cell motion". Bulletin of Mathematical Biology. 73 (3): 658–682. doi:10.1007/s11538-010-9580-x. PMID 20878250. S2CID 37036941.
- ^ Banerjee T, Biswas D, Pal DS, Miao Y, Iglesias PA, Devreotes PN (October 2022). "Spatiotemporal dynamics of membrane surface charge regulates cell polarity and migration". Nature Cell Biology. 24 (10): 1499–1515. doi:10.1038/s41556-022-00997-7. PMC 10029748. PMID 36202973. S2CID 248990694.
- ^ Parent CA, Devreotes PN (April 1999). "A cell's sense of direction". Science. 284 (5415): 765–770. Bibcode:1999Sci...284..765P. doi:10.1126/science.284.5415.765. PMID 10221901.
- ^ Ridley AJ, Schwartz MA, Burridge K, Firtel RA, Ginsberg MH, Borisy G, et al. (December 2003). "Cell migration: integrating signals from front to back". Science. 302 (5651): 1704–1709. Bibcode:2003Sci...302.1704R. doi:10.1126/science.1092053. PMID 14657486. S2CID 16029926.
- ^ Pal DS, Banerjee T, Lin Y, de Trogoff F, Borleis J, Iglesias PA, et al. (July 2023). "Actuation of single downstream nodes in growth factor network steers immune cell migration". Developmental Cell. 58 (13): 1170–1188.e7. doi:10.1016/j.devcel.2023.04.019. PMC 10524337. PMID 37220748.
- ^ Lin Y, Pal DS, Banerjee P, Banerjee T, Qin G, Deng Y, et al. (July 2024). "Ras suppression potentiates rear actomyosin contractility-driven cell polarization and migration". Nature Cell Biology: 1–15. doi:10.1038/s41556-024-01453-4. PMID 38951708.
- ^ Li R, Gundersen GG (November 2008). "Beyond polymer polarity: how the cytoskeleton builds a polarized cell". Nature Reviews. Molecular Cell Biology. 9 (11): 860–873. doi:10.1038/nrm2522. PMID 18946475. S2CID 19500145.
- ^ Meyer AS, Hughes-Alford SK, Kay JE, Castillo A, Wells A, Gertler FB, et al. (June 2012). "2D protrusion but not motility predicts growth factor-induced cancer cell migration in 3D collagen". The Journal of Cell Biology. 197 (6): 721–729. doi:10.1083/jcb.201201003. PMC 3373410. PMID 22665521.
- ^ Coskun H (2006). Mathematical Models for Ameboid Cell Motility and Model Based Inverse Problems (Ph.D. thesis). University of Iowa – via ProQuest.
- ^ Coskun H, Li Y, Mackey MA (January 2007). "Ameboid cell motility: a model and inverse problem, with an application to live cell imaging data". Journal of Theoretical Biology. 244 (2): 169–179. Bibcode:2007JThBi.244..169C. doi:10.1016/j.jtbi.2006.07.025. PMID 16997326.
- ^ Coskun H, Coskun H (March 2011). "Cell physician: reading cell motion: a mathematical diagnostic technique through analysis of single cell motion". Bulletin of Mathematical Biology. 73 (3): 658–82. doi:10.1007/s11538-010-9580-x. PMID 20878250.; Lay summary in: "Mathematicians use cell 'profiling' to detect abnormalities -- including cancer". ScienceDaily.
External links
edit- Cell Migration Gateway The Cell Migration Gateway is a comprehensive and regularly updated resource on cell migration
- The Cytoskeleton and Cell Migration A tour of images and videos by the J. V. Small lab in Salzburg and Vienna