@article {69147, title = {Believing is seeing - the deceptive influence of bias in quantitative microscopy.}, journal = {Journal of Cell Science}, volume = {137}, year = {2024}, month = {2024 Jan 10}, abstract = {

The visual allure of microscopy makes it an intuitively powerful research tool. Intuition, however, can easily obscure or distort the reality of the information contained in an image. Common cognitive biases, combined with institutional pressures that reward positive research results, can quickly skew a microscopy project towards upholding, rather than rigorously challenging, a hypothesis. The impact of these biases on a variety of research topics is well known. What might be less appreciated are the many forms in which bias can permeate a microscopy experiment. Even well-intentioned researchers are susceptible to bias, which must therefore be actively recognized to be mitigated. Importantly, although image quantification has increasingly become an expectation, ostensibly to confront subtle biases, it is not a guarantee against bias and cannot alone shield an experiment from cognitive distortions. Here, we provide illustrative examples of the insidiously pervasive nature of bias in microscopy experiments - from initial experimental design to image acquisition, analysis and data interpretation. We then provide suggestions that can serve as guard rails against bias.

}, keywords = {Bias, Humans, Microscopy, Research Personnel}, issn = {1477-9137}, doi = {10.1242/jcs.261567}, author = {Lee, Rachel M and Eisenman, Leanna R and Khuon, Satya and Aaron, Jesse S and Chew, Teng-Leong} } @article {68954, title = {Direct observation of the conformational states of PIEZO1.}, journal = {Nature}, volume = {620}, year = {2023}, month = {2023 Aug 31}, pages = {1117-1125}, abstract = {

PIEZOs are mechanosensitive ion channels that convert force into chemoelectric signals and have essential roles in diverse physiological settings. In vitro studies have proposed that PIEZO channels transduce mechanical force through the deformation of extensive blades of transmembrane domains emanating from a central ion-conducting pore. However, little is known about how these channels interact with their native environment and which molecular movements underlie activation. Here we directly observe the conformational dynamics of the blades of individual PIEZO1 molecules in a cell using nanoscopic fluorescence imaging. Compared with previous structural models of PIEZO1, we show that the blades are significantly expanded at rest by the bending stress exerted by the plasma membrane. The degree of expansion varies dramatically along the length of the blade, where decreased binding strength between subdomains can explain increased flexibility of the distal blade. Using chemical and mechanical modulators of PIEZO1, we show that blade expansion and channel activation are correlated. Our findings begin to uncover how PIEZO1 is activated in a native environment. More generally, as we reliably detect conformational shifts of single nanometres from populations of channels, we expect that this approach will serve as a framework for the structural analysis of membrane proteins through nanoscopic imaging.

}, issn = {1476-4687}, doi = {10.1038/s41586-023-06427-4}, author = {Mulhall, Eric M and Gharpure, Anant and Lee, Rachel M and Dubin, Adrienne E and Aaron, Jesse S and Marshall, Kara L and Spencer, Kathryn R and Reiche, Michael A and Henderson, Scott C and Chew, Teng-Leong and Patapoutian, Ardem} } @article {68715, title = {Extracellular matrix assembly stress initiates Drosophila central nervous system morphogenesis.}, journal = {Developmental Cell}, year = {2023}, month = {2023 Apr 17}, abstract = {

Forces controlling tissue morphogenesis are attributed to cellular-driven activities, and any role for extracellular matrix (ECM) is assumed to be passive. However, all polymer networks, including ECM, can develop autonomous stresses during their assembly. Here, we examine the morphogenetic function of an ECM before reaching homeostatic equilibrium by analyzing de novo ECM assembly during Drosophila ventral nerve cord (VNC) condensation. Asymmetric VNC shortening and a rapid decrease in surface area correlate with the exponential assembly of collagen IV (Col4) surrounding the tissue. Concomitantly, a transient developmentally induced Col4 gradient leads to coherent long-range flow of ECM, which equilibrates the Col4 network. Finite element analysis and perturbation of Col4 network formation through the generation of dominant Col4 mutations that affect assembly reveal that VNC morphodynamics is partially driven by a sudden increase in ECM-driven surface tension. These data suggest that ECM assembly stress and associated network instabilities can actively participate in tissue morphogenesis.

}, issn = {1878-1551}, doi = {10.1016/j.devcel.2023.03.019}, author = {Serna-Morales, Eduardo and S{\'a}nchez-S{\'a}nchez, Besaiz J and Marcotti, Stefania and Nichols, Angus and Bhargava, Anushka and Dragu, Anca and Hirvonen, Liisa M and Diaz-de-la-Loza, Maria-Del-Carmen and Mink, Matyas and Cox, Susan and Rayfield, Emily and Lee, Rachel M and Hobson, Chad M and Chew, Teng-Leong and Stramer, Brian M} } @article {68784, title = {Extracellular matrix assembly stress initiates Drosophila central nervous system morphogenesis.}, journal = {Developmental Cell}, volume = {58}, year = {2023}, month = {2023 May 22}, pages = {825-835.e6}, abstract = {

Forces controlling tissue morphogenesis are attributed to cellular-driven activities, and any role for extracellular matrix (ECM) is assumed to be passive. However, all polymer networks, including ECM, can develop autonomous stresses during their assembly. Here, we examine the morphogenetic function of an ECM before reaching homeostatic equilibrium by analyzing de novo ECM assembly during Drosophila ventral nerve cord (VNC) condensation. Asymmetric VNC shortening and a rapid decrease in surface area correlate with the exponential assembly of collagen IV (Col4) surrounding the tissue. Concomitantly, a transient developmentally induced Col4 gradient leads to coherent long-range flow of ECM, which equilibrates the Col4 network. Finite element analysis and perturbation of Col4 network formation through the generation of dominant Col4 mutations that affect assembly reveal that VNC morphodynamics is partially driven by a sudden increase in ECM-driven surface tension. These data suggest that ECM assembly stress and associated network instabilities can actively participate in tissue morphogenesis.

}, keywords = {Animals, Central Nervous System, Drosophila, Extracellular Matrix, Morphogenesis}, issn = {1878-1551}, doi = {10.1016/j.devcel.2023.03.019}, author = {Serna-Morales, Eduardo and S{\'a}nchez-S{\'a}nchez, Besaiz J and Marcotti, Stefania and Nichols, Angus and Bhargava, Anushka and Dragu, Anca and Hirvonen, Liisa M and Diaz-de-la-Loza, Maria-Del-Carmen and Mink, Matyas and Cox, Susan and Rayfield, Emily and Lee, Rachel M and Hobson, Chad M and Chew, Teng-Leong and Stramer, Brian M} } @article {67987, title = {When light meets biology - how the specimen affects quantitative microscopy.}, journal = {Journal of Cell Science}, volume = {135}, year = {2022}, month = {2022 Mar 15}, abstract = {

Fluorescence microscopy images should not be treated as perfect representations of biology. Many factors within the biospecimen itself can drastically affect quantitative microscopy data. Whereas some sample-specific considerations, such as photobleaching and autofluorescence, are more commonly discussed, a holistic discussion of sample-related issues (which includes less-routine topics such as quenching, scattering and biological anisotropy) is required to appropriately guide life scientists through the subtleties inherent to bioimaging. Here, we consider how the interplay between light and a sample can cause common experimental pitfalls and unanticipated errors when drawing biological conclusions. Although some of these discrepancies can be minimized or controlled for, others require more pragmatic considerations when interpreting image data. Ultimately, the power lies in the hands of the experimenter. The goal of this Review is therefore to survey how biological samples can skew quantification and interpretation of microscopy data. Furthermore, we offer a perspective on how to manage many of these potential pitfalls.

}, issn = {1477-9137}, doi = {10.1242/jcs.259656}, author = {Reiche, Michael A and Aaron, Jesse S and Boehm, Ulrike and DeSantis, Michael C and Hobson, Chad M and Khuon, Satya and Lee, Rachel M and Chew, Teng-Leong} }