---

Academic Qualifications

2003-2010 Postdoctoral Fellow, Physics department and Free Electron Laser Lab, Duke University, USA
2003 Postdoctoral Fellow, Institute of Laser Engineering, Osaka University, Japan
2003 Ph.D., Osaka University, Japan
2000 M.E., Osaka University, Japan
1998 B.E., Hokkaido University, Japan

Research Areas

Tissue dynamics, apoptosis, Drosophila development

Research Interests

Our lab studies tissue dynamics in living embryo and cultured tissue. We are interested in two particular aspects, how cell mechanics that evolve over time and in space emerge as large-scale tissue dynamics (as an intrinsic force), and how cell mechanics arises from tissue dynamics and feedback to cellular and molecular function (as an extrinsic force). To study the mechanical interactions between cells within a tissue, we detect and extract the mechanical signatures (e.g., cell-cell adhesion, cytoskeleton, and mechanical forces) from a tissue with an interdisciplinary approach that combines imaging, quantitative analysis, gene manipulation, biophysical manipulation tools (e.g., laser ablation), and biophysical modeling. The major scientific topics we have been asking lie in 2 areas: Mechanical role of apoptosis (a.k.a. apoptotic force) within a tissue, and 3D cell shape changes during collective cell migration.

Biography

Dr Toyama had a formal training in physics and engineering during graduate (Osaka Univ.) and undergraduate (Hokkaido Univ.) school in Japan. In 2003, he earned a Ph.D. in Engineering where his doctoral work was focused on plasma physics and laser driven nuclear fusion. He then embraced biophysics and mechanobiology during his postdoctoral carrier at Duke Univ. under supervision of Prof. Glenn Edwards (Physics department) and Prof. Dan Kiehart (Biology department). Dr Toyama joined Department of Biological Sciences at National University of Singapore as an Assistant Professor in 2010, and promoted as an Associate Professor in 2018. He also has an appointment as a Principal Investigator in Mechanobiology Institute since 2010.

Selected Publications

See Latest Publications

1. Sun Z, Amourda C, Shagirov M, Hara Y, Saunders TE, Toyama Y. “Basolateral protrusion and apical contraction cooperatively drive Drosophila germband extension.” Nature Cell Biology (2017, in press)

2. Saw TB, Doostmohammadi A, Nier V, Kocgozlu L, Thampi S, Toyama Y, Marcq P, Lim CT*, Yeomans JM*, Ladoux B* “Topological defects in epithelia govern cell death and extrusion” Nature (2017, in press)

3. Teng X, Qin L, Le Borgne R, Toyama Y. “Remodeling of adhesion and modulation of mechanical tensile forces during apoptosis in Drosophila epithelium” Development 144, 95-105 (2017)

4. Bertocchi C, Wang Y, Ravasio A, Hara Y, Wu Y, Sailov T, Baird MA, Davidson MW, Zaidel-Bar R, Toyama Y, Ladoux B, Mege RM, Kanchanawong P. “Nanoscale architecture of cadherin-based cell adhesions” Nature Cell Biology 19, 28-37 (2017)

5. Kocgozlu L*, Saw TB*, Le AP, Yow I, Shagirov M, Wong E, Mège RM, Lim CT, Toyama Y**, Ladoux B** *, **: Equal contribution “Epithelial cell packing induces distinct modes of cell extrusions” Current Biology 26, 2942-50 (2016)

6. Hara Y, Shagirov M, Toyama Y. “Cell boundary elongation by non-autonomous contractility in cell oscillation” Current Biology 26, 2388-96 (2016)

7. Ravasio A, Cheddadi I, Chen T, Pereira T, Ong HT, Bertocchi C, Brugues A, Jacinto A, Kabla AJ, Toyama Y, Trepat X, Gov N, Neves de Almeida L, Ladoux B. “Gap geometry dictates epithelial closure efficiency” Nature Communications 6, 7683 (2015)

8. Vedula S.R.K, Peyret G, Cheddadi I, Chen T, Brugués A, Hirata H, Lopez-Menendez H, Toyama Y, Almeida L, Trepat X, Lim CT, Ladoux B  “Mechanics of epithelial closure over non-adherent environments” Nature Communications 6, 6111 (2015)

9. Kawashima T, Maruyama D, Shagirov M, Hamamura Y, Li J, Yelagandula R, Toyama Y, Berger F “Dynamic F-actin movement is essential for fertilization in Arabidopsis thaliana” eLife 3, 04501 (2014)

10. Vedula S.R.K, Hirata H, Nai MH, Brugés A, Toyama Y, Trepat X, Lim CT and Ladoux B.  “Epithelial bridges maintain tissue integrity during collective cell migration” Nature Material 13, 87–96 (2014)

11. Sokolow, A, Toyama, Y, Kiehart, D.P. and Edwards, G.S. “Cell ingression and apical shape oscillations during dorsal closure in Drosophila” Biophysical Journal 102, 969-979 (2012)     

12. Teng, X, Toyama Y. “Apoptotic force: Active mechanical function of cell death during morphogenesis” Development Growth and Differentiation. 53, 269-276 (2011) Review

13. Layton, A.T.,* Toyama, Y.,* Yang, G-Q.,* Edwards, G.S., Kiehart, D.P., Venakides, S. *: Equal contribution. “Drosophila Morphogenesis: Tissue Force Laws and the Modeling of Dorsal Closure” HFSP (Human Frontier Science Program) Journal 3, 441-460 (2009). 

14. Toyama, Y., Peralta, X.G., Wells, A.R., Kiehart, D.P., and Edwards, G.S. “Apoptotic force and tissue dynamics during Drosophila embryogenesis” Science 321, 1683-1686 (2008).

15. Rodriguez-Diaz, A., Toyama, Y., Abravanel, D.L., Wiemann, J.M., Wells, A.R., Tulu, U.S., Edwards, G.S., and Kiehart, D.P. “Actomyosin purse strings: renewable resources that make morphogenesis robust and resilient” HFSP Journal 2, 220-237 (2008).

16. Peralta, X.G., Toyama, Y., Kiehart, D.P., and Edwards, G.S. “Emergent properties during dorsal closure in Drosophila morphogenesis” Physical Biology 5, 015004 (2008).

17. Peralta, X.G., Toyama, Y., Hutson, M.S., Montague, R., Venakides, S., Kiehart, D.P., and Edwards, G.S. “Upregulation of forces and morphogenic asymmetries in dorsal closure during Drosophila development” Biophysical Journal 92, 2583-2596 (2007).

18. Kiehart, D.P., Tokutake, Y., Chang, M.S., Hutson, M.S., Wiemann, J., Peralta, X.G., Toyama, Y., Wells, A.R., Rodriguez, A., and Edwards, G.S.  “Ultraviolet Laser Microbeam for Dissection of Drosophila Embryos. ” Cell Biology: A Laboratory Handbook, 3rd edition, edited by J.E. Celis (2006), pp. 87-103, Elsevier (Chapter 9)