García-Calvo José, López-Andarias Javier, Maillard Jimmy, Mercier Vincent, Roffay Chloé, Roux Aurélien, Fürstenberg Alexandre, Sakai Naomi, Matile Stefan
School of Chemistry and Biochemistry, NCCR Chemical Biology, University of Geneva Geneva Switzerland
Chem Sci. 2022 Feb 3;13(7):2086-2093. doi: 10.1039/d1sc05208j. eCollection 2022 Feb 16.
HydroFlippers are introduced as the first fluorescent membrane tension probes that report simultaneously on membrane compression and hydration. The probe design is centered around a sensing cycle that couples the mechanical planarization of twisted push-pull fluorophores with the dynamic covalent hydration of their exocyclic acceptor. In FLIM images of living cells, tension-induced deplanarization is reported as a decrease in fluorescence lifetime of the dehydrated mechanophore. Membrane hydration is reported as the ratio of the photon counts associated to the hydrated and dehydrated mechanophores in reconvoluted lifetime frequency histograms. Trends for tension-induced decompression and hydration of cellular membranes of interest (MOIs) covering plasma membrane, lysosomes, mitochondria, ER, and Golgi are found not to be the same. Tension-induced changes in mechanical compression are rather independent of the nature of the MOI, while the responsiveness to changes in hydration are highly dependent on the intrinsic order of the MOI. These results confirm the mechanical planarization of push-pull probes in the ground state as most robust mechanism to routinely image membrane tension in living cells, while the availability of simultaneous information on membrane hydration will open new perspectives in mechanobiology.
HydroFlippers作为首个能够同时报告膜压缩和水合作用的荧光膜张力探针被引入。该探针设计围绕一个传感循环展开，该循环将扭曲的推拉荧光团的机械平面化与其环外受体的动态共价水合作用相结合。在活细胞的荧光寿命成像（FLIM）图像中，张力诱导的平面化表现为脱水机械荧光团荧光寿命的降低。膜水合作用以反卷积寿命频率直方图中与水合和脱水机械荧光团相关的光子计数之比来表示。研究发现，覆盖质膜、溶酶体、线粒体、内质网和高尔基体的感兴趣细胞膜（MOI）的张力诱导减压和水合作用趋势并不相同。张力诱导的机械压缩变化与MOI的性质相当无关，而对水合作用变化的响应高度依赖于MOI的固有有序性。这些结果证实了基态下推拉探针的机械平面化是在活细胞中常规成像膜张力的最可靠机制，而同时获得的膜水合作用信息将为力学生物学开辟新的前景。
