ORCID Profile
0000-0002-8425-7297
Current Organisations
University of Cambridge
,
Max-Planck-Zentrum für Physik und Medizin
,
Friedrich-Alexander-Universität Erlangen-Nürnberg
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Publisher: Springer Science and Business Media LLC
Date: 19-06-2017
DOI: 10.1038/NCB3561
Abstract: Cellular forces are crucial for many biological processes but current methods to image them have limitations with respect to data analysis, resolution and throughput. Here, we present a robust approach to measure mechanical cell-substrate interactions in erse biological systems by interferometrically detecting deformations of an elastic micro-cavity. Elastic resonator interference stress microscopy (ERISM) yields stress maps with exceptional precision and large dynamic range (2 nm displacement resolution over a >1 μm range, translating into 1 pN force sensitivity). This enables investigation of minute vertical stresses (<1 Pa) involved in podosome protrusion, protein-specific cell-substrate interaction and amoeboid migration through spatial confinement in real time. ERISM requires no zero-force reference and avoids phototoxic effects, which facilitates force monitoring over multiple days and at high frame rates and eliminates the need to detach cells after measurements. This allows observation of slow processes such as differentiation and further investigation of cells, for ex le, by immunostaining.
Publisher: Proceedings of the National Academy of Sciences
Date: 17-03-2022
Abstract: Implantable electronic medical devices (IEMDs) are used for some clinical applications, representing an exciting prospect for the transformative treatment of intractable conditions such Parkinson’s disease, deafness, and paralysis. The use of IEMDs is limited at the moment because, over time, a foreign body reaction (FBR) develops at the device–neural interface such that ultimately the IEMD fails and needs to be removed. Here, we show that macrophage nucleotide-binding oligomerization domain-like receptor family pyrin domain containing 3 (NLRP3) inflammasome activity drives the FBR in a nerve injury model yet integration of an NLRP3 inhibitor into the device prevents FBR while allowing full healing of damaged neural tissue to occur.
Publisher: Society for Neuroscience
Date: 11-02-2015
DOI: 10.1523/JNEUROSCI.1150-14.2015
Abstract: Drosophila phototransduction is mediated via a G-protein-coupled PLC cascade. Recent evidence, including the demonstration that light evokes rapid contractions of the photoreceptors, suggested that the light-sensitive channels (TRP and TRPL) may be mechanically gated, together with protons released by PLC-mediated PIP 2 hydrolysis. If mechanical gating is involved we predicted that the response to light should be influenced by altering the physical properties of the membrane. To achieve this, we used diet to manipulate the degree of saturation of membrane phospholipids. In flies reared on a yeast diet, lacking polyunsaturated fatty acids (PUFAs), mass spectrometry showed that the proportion of polyunsaturated phospholipids was sevenfold reduced (from 38 to ∼5%) but rescued by adding a single species of PUFA (linolenic or linoleic acid) to the diet. Photoreceptors from yeast-reared flies showed a 2- to 3-fold increase in latency and time to peak of the light response, without affecting quantum bump waveform. In the absence of Ca 2+ influx or in trp mutants expressing only TRPL channels, sensitivity to light was reduced up to ∼10-fold by the yeast diet, and essentially abolished in hypomorphic G-protein mutants ( G α q ). PLC activity appeared little affected by the yeast diet however, light-induced contractions measured by atomic force microscopy or the activation of ectopic mechanosensitive gramicidin channels were also slowed ∼2-fold. The results are consistent with mechanosensitive gating and provide a striking ex le of how dietary fatty acids can profoundly influence sensory performance in a classical G-protein-coupled signaling cascade.
Publisher: American Association for the Advancement of Science (AAAS)
Date: 12-10-2012
Abstract: There has been a link missing in our understanding of the biochemical signaling mechanism initiated when photons are absorbed by rhodopsin in the photoreceptor cells of Drosophila eyes. Photoisomerization of rhodopsin activates a heterotrimeric guanine nucleotide—binding protein which leads to activation of phospholipase C. But how phospholipase C activates the transient receptor potential (TRP) or the transient receptor potential–like (TRPL) ion channels that produce the rest of the cellular response has been unclear. Hardie and Franze (p. 260 see the Perspective by Liman ) propose that there is a physical mechanism at work. Atomic force microscopy revealed light-induced contractions of photoreceptor cells. Consistent with a physical coupling mechanism, manipulations of the membrane altered responses of the photoreceptor cells to light. Thus, physical changes in the membrane appear to couple phospholipase C activity to the opening of mechanosensitive TRP and TRPL channels.
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Kristian Franze.