We obtained significant insight into the principles of tissue mechanics, by exploiting the experimental advantages of the model organism of Drosophila and applying an interdisciplinary research approach combining genetics, quantitative imaging and biophysics in a whole animal system.
First, we found significant alteration of the muscle mechanical properties (elasticity/viscosity) in Ilk mutant embryos compared with wild type (wt), leading to the conclusion that ILK modulates indeed integrin mechanotransmission. Second, we found significant decrease in the number and amplitude of muscle contraction in Ilk null mutants in comparison to the wt. This result strongly suggests that the overall applied tension in the Ilk mutant embryos is decreased. Third, we found that the molecular force transmitted across Talin is higher in Ilk mutant embryos in comparison to the wt at similar developmental stages. Although, the overall force is decreased, the molecular mechanical tension across Talin is higher. Therefore, the mechanical force could be distributed on fewer Talin proteins in Ilk-/-. Previous data from the host lab indicate that the immobile fraction of integrins in Ilk-/- is decreased compared to wt. We suggest that the mechanically engaged Talin molecules are fewer in Ilk-/-. Collectively, we conclude that ILK modulates integrin mechanotransmission by altering the number of Talin molecules that transmit molecular force.
Application and exploitation of research results
This proposal advanced the mechanotransduction field by providing new cutting-edge knowledge of how integrin adhesome proteins work together to achieve force-dependent strengthening of cell-matrix adhesions in the whole organism, using an interdisciplinary research approach combining genetics, quantitative imaging methodologies, mathematical modelling, and biophysical unique tools that enabled quantification of forces in the living organism. The range of implications of this proposed work is broad and significant, because mechanotransduction emerges as a vital determinant of physiological processes including muscle contractility, tissue formation and organogenesis. Moreover, dysregulated tissue mechanics contribute to many pathologies including heart failure, atherosclerosis, muscle degeneration, bone dysfunction, wound healing, cancer and metastasis.
Dissemination of results
Peer-review publications: One publication entitled “Talin regulates steady-state tensional homeostasis to drive vascular morphodynamics and cancer” (Nikolopoulou P et al) is already submitted and currently is under review. This work was done in collaboration with the group of Dr Kostourou at the BSCR Alex. Fleming, Athens, Greece.
Together with Dr Christos Zervas we have started to draft a manuscript describing the role of ILK in coupling mechanical forces to Talin at Drosophila muscle attachment sites.
A third manuscript is under preparation in the host lab describing the functional role of ILK in the follicular epithelium (Keramidioti et. al, manuscript in preparation).
Conferences:
1) “BioImaging approaches to decipher mechanotransduction in Drosophila muscle attachment sites in vivo”
https://bioimaging.gr/images/site/news/Advanced_Functional_Imaging_programme.pdf(s’ouvre dans une nouvelle fenêtre).
2) 19th International Congress of Developmental Biology, Algarve, Portugal, 16-20/10/2022.
Seminars: I participated as external teacher in the Athens International Master’s Programme in Neurosciences, University of Athens. Over the last 2 years I have delivered 2 lectures on FLIM/FRET principles and related research data. In addition, I have presented one research seminar in the BRFAA institute (12/2019), as part of the institutional research seminars, while one more is schedulled for early 2023.
Lab web site: A distinct web page linked with the host lab was created named “MechanoGenetic”.
