Imaging actin organisation and dynamics in 3D.

The actin cytoskeleton plays a critical role in cell architecture and the control of fundamental processes including cell division, migration and survival. The dynamics and organisation of F-actin have been widely studied in a breadth of cell types on classical two-dimensional (2D) surfaces. Recent advances in optical microscopy have enabled interrogation of these cytoskeletal networks in cells within three-dimensional (3D) scaffolds, tissues and in vivo. Emerging studies indicate that the dimensionality experienced by cells has a profound impact on the structure and function of the cytoskeleton, with cells in 3D environments exhibiting cytoskeletal arrangements that differ to cells in 2D environments. However, the addition of a third (and fourth, with time) dimension leads to challenges in sample preparation, imaging and analysis, necessitating additional considerations to achieve the required signal-to-noise ratio and spatial and temporal resolution. Here, we summarise the current tools for imaging actin in a 3D context and highlight examples of the importance of this in understanding cytoskeletal biology and the challenges and opportunities in this domain.

Sox9 Accelerates Vascular Aging by Regulating Extracellular Matrix Composition and Stiffness.

BACKGROUND: Vascular calcification and increased extracellular matrix (ECM) stiffness are hallmarks of vascular aging. Sox9 (SRY-box transcription factor 9) has been implicated in vascular smooth muscle cell (VSMC) osteo/chondrogenic conversion; however, its relationship with aging and calcification has not been studied. METHODS: Immunohistochemistry was performed on human aortic samples from young and aged patients. Young and senescent primary human VSMCs were induced to produce ECM, and Sox9 expression was manipulated using adenoviral overexpression and depletion. ECM properties were characterized using atomic force microscopy and proteomics, and VSMC phenotype on hydrogels and the ECM were examined using confocal microscopy. RESULTS: In vivo, Sox9 was not spatially associated with vascular calcification but correlated with the senescence marker p16 (cyclin-dependent kinase inhibitor 2A). In vitro Sox9 showed mechanosensitive responses with increased expression and nuclear translocation in senescent cells and on stiff matrices. Sox9 was found to regulate ECM stiffness and organization by orchestrating changes in collagen (Col) expression and reducing VSMC contractility, leading to the formation of an ECM that mirrored that of senescent cells. These ECM changes promoted phenotypic modulation of VSMCs, whereby senescent cells plated on ECM synthesized from cells depleted of Sox9 returned to a proliferative state, while proliferating cells on a matrix produced by Sox9 expressing cells showed reduced proliferation and increased DNA damage, reiterating features of senescent cells. LH3 (procollagen-lysine, 2-oxoglutarate 5-dioxygenase 3) was identified as an Sox9 target and key regulator of ECM stiffness. LH3 is packaged into extracellular vesicles and Sox9 promotes extracellular vesicle secretion, leading to increased LH3 deposition within the ECM. CONCLUSIONS: These findings highlight the crucial role of ECM structure and composition in regulating VSMC phenotype. We identify a positive feedback cycle, whereby cellular senescence and increased ECM stiffening promote Sox9 expression, which, in turn, drives further ECM modifications to further accelerate stiffening and senescence.

Characterisation and correction of polarisation effects in fluorescently labelled fibres.

Many biological structures take the form of fibres and filaments, and quantitative analysis of fibre organisation is important for understanding their functions in both normal physiological conditions and disease. In order to visualise these structures, fibres can be fluorescently labelled and imaged, with specialised image analysis methods available for quantifying the degree and strength of fibre alignment. Here we show that fluorescently labelled fibres can display polarised emission, with the strength of this effect varying depending on structure and fluorophore identity. This can bias automated analysis of fibre alignment and mask the true underlying structural organisation. We present a method for quantifying and correcting these polarisation effects without requiring polarisation-resolved microscopy and demonstrate its efficacy when applied to images of fluorescently labelled collagen gels, allowing for more reliable characterisation of fibre microarchitecture.

The time is now: addressing implicit bias in obstetrics and gynecology education.

Obstetrician-gynecologists can improve the learning environment and patient care by addressing implicit bias. Accumulating evidence demonstrates that racial and gender-based discrimination is woven into medical education, formal curricula, patient-provider-trainee interactions in the clinical workspace, and all aspects of learner assessment. Implicit bias negatively affects learners in every space. Strategies to address implicit bias at the individual, interpersonal, institutional, and structural level to improve the well-being of learners and patients are needed. The authors review an approach to addressing implicit bias in obstetrics and gynecology education, which includes: (1) curricular design using an educational framework of antiracism and social justice theories, (2) bias awareness and management pedagogy throughout the curriculum, (3) elimination of stereotypical patient descriptions from syllabi and examination questions, and (4) critical review of epidemiology and evidence-based medicine for underlying assumptions based on discriminatory practices or structural racism that unintentionally reinforce stereotypes and bias. The movement toward competency-based medical education and holistic evaluations may result in decreased bias in learner assessment. Educators may wish to monitor grades and narratives for bias as a form of continuous educational equity improvement. Given that practicing physicians may have little training in this area, faculty development efforts in bias awareness and mitigation strategies may have significant impact on learner well-being.

A method for reproducible high-resolution imaging of 3D cancer cell spheroids.

Multicellular tumour cell spheroids embedded within three-dimensional (3D) hydrogels or extracellular matrices (ECM) are widely used as models to study cancer growth and invasion. Standard methods to embed spheroids in 3D matrices result in random placement in space which limits the use of inverted fluorescence microscopy techniques, and thus the resolution that can be achieved to image molecular detail within the intact spheroid. Here, we leverage UV photolithography to microfabricate PDMS (polydimethylsiloxane) stamps that allow for generation of high-content, reproducible well-like structures in multiple different imaging chambers. Addition of multicellular tumour spheroids into stamped collagen structures allows for precise positioning of spheroids in 3D space for reproducible high-/super-resolution imaging. Embedded spheroids can be imaged live or fixed and are amenable to immunostaining, allowing for greater flexibility of experimental approaches. We describe the use of these spheroid imaging chambers to analyse cell invasion, cell-ECM interaction, ECM alignment, force-dependent intracellular protein dynamics and extension of fine actin-based protrusions with a variety of commonly used inverted microscope platforms. This method enables reproducible, high-/super-resolution live imaging of multiple tumour spheroids, that can be potentially extended to visualise organoids and other more complex 3D in vitro systems.

Out of the mouths of Peer Leaders: Perspectives on how to improve a telephone-based peer support intervention in type 2 diabetes.

OBJECTIVE: To explore the experiences of peer leaders with respect to delivering core components of a 12-month, telephone-based peer support intervention in type 2 diabetes within a tertiary-care setting. METHODS: Seventeen peer leaders were recruited and interviewed. Interviews lasted approximately 20 to 45 min, were audio-taped, and transcribed verbatim. The transcripts were analysed by two team members using the qualitative descriptive approach. FINDINGS: Peer leaders reported mutually beneficial and reciprocal relationships with participants. They encountered challenges in maintaining regular contact with participants and in motivating them to make lifestyle changes. To improve the programme, peer leaders suggested having more frequent - but shorter - training sessions and reducing the diabetes education component of the training programme. To enhance the intervention fidelity and retention rate, they recommended matching peer leaders to participants on more meaningful variables (e.g. diabetes-related commonalities, personality, life experiences, etc.) beyond just gender, geographic proximity and availability. They also requested more frequent face-to-face contacts with participants (Modality of Contact), and additional ongoing support from the research team. CONCLUSION: Peer leaders were satisfied with the intervention design. However, future studies may consider more comprehensive peer leader-matching algorithms and increased opportunities for in-person communication modalities. CLINICALTRIALS: gov Identifier: NCT02804620.

Integration of health systems science and women's healthcare.

Health systems science addresses the complex interactions in healthcare delivery. At its core, health systems science describes the intricate details required to provide high-quality care to individual patients by assisting them in navigating the multifaceted and often complicated US healthcare delivery system. With advances in technology, informatics, and communication, the modern physician is required to have a strong working knowledge of health systems science to provide effective, low-cost, high-quality care to patients. Medical educators are poised to introduce health systems science concepts alongside the basic science and clinical science courses already being taught in medical school. Because of the common overlap of women's healthcare subject matter with health systems science topics, such as interprofessional collaboration, ethics, advocacy, and quality improvement, women's health medical educators are at the forefront of incorporating health systems science into the current medical school educational model. Here, the authors have described the concept of health systems science and discussed both why and how it should be integrated into the undergraduate medical education curriculum. Medical educators must develop physicians of the future who can not only provide excellent patient care but also actively participate in the advancement and improvement of the healthcare delivery system.

Artifact-free high-density localization microscopy analysis.

High-density analysis methods for localization microscopy increase acquisition speed but produce artifacts. We demonstrate that these artifacts can be eliminated by the combination of Haar wavelet kernel (HAWK) analysis with standard single-frame fitting. We tested the performance of this method on synthetic, fixed-cell, and live-cell data, and found that HAWK preprocessing yielded reconstructions that reflected the structure of the sample, thus enabling high-speed, artifact-free super-resolution imaging of live cells.

A Proposed Shared Vision for Leadership Development for all Medical Students: A Call from a Coalition of Diverse Medical Schools.

Issue: Despite clear relevance, need, descriptive literature, and student interest, few schools offer required curriculum to develop leadership skills. This paper outlines a proposed shared vision for leadership development drawn from a coalition of diverse medical schools. We advocate that leadership development is about self (looking inward), teams (not hierarchy), and change (looking outward). We propose that leadership development is for all medical students, not for a subset, and we believe that leadership curricula and programs must be experiential and applied. Evidence: This paper also draws on the current literature and the experience of medical schools participating in the American Medical Association's (AMA) Accelerating Change in Medical Education Consortium, confronts the common arguments against leadership training in medical education, and provides three cross-cutting principles that we believe must each be incorporated in all medical student-centered leadership development programs as they emerge and evolve at medical schools. Implications: By confronting common arguments against leadership training and providing a framework for such training, we give medical educators important tools and insights into developing leadership training for all students at their institutions.

The Rényi divergence enables accurate and precise cluster analysis for localization microscopy.

Motivation: Clustering analysis is a key technique for quantitatively characterizing structures in localization microscopy images. To build up accurate information about biological structures, it is critical that the quantification is both accurate (close to the ground truth) and precise (has small scatter and is reproducible). Results: Here, we describe how the Rényi divergence can be used for cluster radius measurements in localization microscopy data. We demonstrate that the Rényi divergence can operate with high levels of background and provides results which are more accurate than Ripley's functions, Voronoi tesselation or DBSCAN. Availability and implementation: The data supporting this research and the software described are accessible at the following site: https://dx.doi.org/10.18742/RDM01-316. Correspondence and requests for materials should be addressed to the corresponding author. Supplementary information: Supplementary data are available at Bioinformatics online.

"They're always there": resident experiences of living with rats in a disadvantaged urban neighbourhood.

BACKGROUND: The presence of urban rats in the neighbourhood environment may negatively impact the physical and mental health of residents. Our study sought to describe the experiences with, perceptions of, and feelings towards rats and rat control efforts among a group of disadvantaged urban residents in Vancouver, Canada. METHODS: Semi-structured interviews were held with 20 members of the Vancouver Area Network of Drug Users (VANDU) recruited by VANDU staff. Interviews were audio recorded, transcribed, and analyzed using thematic analysis. RESULTS: Participants reported daily sightings of rats and close contact during encounters. Participants generally disliked encountering rats, raising issues of health and safety for themselves and the community due to the belief that rats carry disease. Fear of rats was common, and in some cases resulted in avoidance of rats. Effects of rats on participants were particularly pronounced for those living with rats in the home or for homeless participants who described impacts on sleep due to the sounds made by rats. Although rats were viewed as more problematic in their neighbourhood than elsewhere in Vancouver, participants believed there to be a lack of neighbourhood-level control initiatives that angered and disheartened participants. In combination with other community-level concerns (e.g., housing quality and availability), the presence of rats was viewed by some to align with a general disregard for the community and its residents. CONCLUSIONS: This study suggests that the presence of rats in urban centres may have several consequences on the physical and mental health of residents living in close contact with them. These effects may be exacerbated with continued contact with rats and when residents perceive a lack of initiative to control rats in their neighbourhood. As such, research and policies aimed at mitigating the health risks posed by rats should extend beyond disease-related risk and incorporate diverse health outcomes.

Investigation of podosome ring protein arrangement using localization microscopy images.

Podosomes are adhesive structures formed on the plasma membrane abutting the extracellular matrix of macrophages, osteoclasts, and dendritic cells. They consist of an f-actin core and a ring structure composed of integrins and integrin-associated proteins. The podosome ring plays a major role in adhesion to the underlying extracellular matrix, but its detailed structure is poorly understood. Recently, it has become possible to study the nano-scale structure of podosome rings using localization microscopy. Unlike traditional microscopy images, localization microscopy images are reconstructed using discrete points, meaning that standard image analysis methods cannot be applied. Here, we present a pipeline for podosome identification, protein position calculation, and creating a podosome ring model for use with localization microscopy data.

Correlative super-resolution fluorescence and electron microscopy using conventional fluorescent proteins in vacuo.

Super-resolution light microscopy, correlative light and electron microscopy, and volume electron microscopy are revolutionising the way in which biological samples are examined and understood. Here, we combine these approaches to deliver super-accurate correlation of fluorescent proteins to cellular structures. We show that YFP and GFP have enhanced blinking properties when embedded in acrylic resin and imaged under partial vacuum, enabling in vacuo single molecule localisation microscopy. In conventional section-based correlative microscopy experiments, the specimen must be moved between imaging systems and/or further manipulated for optimal viewing. These steps can introduce undesirable alterations in the specimen, and complicate correlation between imaging modalities. We avoided these issues by using a scanning electron microscope with integrated optical microscope to acquire both localisation and electron microscopy images, which could then be precisely correlated. Collecting data from ultrathin sections also improved the axial resolution and signal-to-noise ratio of the raw localisation microscopy data. Expanding data collection across an array of sections will allow 3-dimensional correlation over unprecedented volumes. The performance of this technique is demonstrated on vaccinia virus (with YFP) and diacylglycerol in cellular membranes (with GFP).

Inflammasome activation causes dual recruitment of NLRC4 and NLRP3 to the same macromolecular complex.

Pathogen recognition by nucleotide-binding oligomerization domain-like receptor (NLR) results in the formation of a macromolecular protein complex (inflammasome) that drives protective inflammatory responses in the host. It is thought that the number of inflammasome complexes forming in a cell is determined by the number of NLRs being activated, with each NLR initiating its own inflammasome assembly independent of one another; however, we show here that the important foodborne pathogen Salmonella enterica serovar Typhimurium (S. Typhimurium) simultaneously activates at least two NLRs, whereas only a single inflammasome complex is formed in a macrophage. Both nucleotide-binding domain and leucine-rich repeat caspase recruitment domain 4 and nucleotide-binding domain and leucine-rich repeat pyrin domain 3 are simultaneously present in the same inflammasome, where both NLRs are required to drive IL-1ß processing within the Salmonella-infected cell and to regulate the bacterial burden in mice. Superresolution imaging of Salmonella-infected macrophages revealed a macromolecular complex with an outer ring of apoptosis-associated speck-like protein containing a caspase activation and recruitment domain and an inner ring of NLRs, with active caspase effectors containing the pro-IL-1ß substrate localized internal to the ring structure. Our data reveal the spatial localization of different components of the inflammasome and how different members of the NLR family cooperate to drive robust IL-1ß processing during Salmonella infection.

Super-resolution imaging in live cells.

Over the last twenty years super-resolution fluorescence microscopy has gone from proof-of-concept experiments to commercial systems being available in many labs, improving the resolution achievable by up to a factor of 10 or more. There are three major approaches to super-resolution, stimulated emission depletion microscopy, structured illumination microscopy, and localisation microscopy, which have all produced stunning images of cellular structures. A major current challenge is optimising performance of each technique so that the same sort of data can be routinely taken in live cells. There are several major challenges, particularly phototoxicity and the speed with which images of whole cells, or groups of cells, can be acquired. In this review we discuss the various approaches which can be successfully used in live cells, the tradeoffs in resolution, speed, and ease of implementation which one must make for each approach, and the quality of results that one might expect from each technique.

Emergence of embryonic pattern through contact inhibition of locomotion.

The pioneering cell biologist Michael Abercrombie first described the process of contact inhibition of locomotion more than 50 years ago when migrating fibroblasts were observed to rapidly change direction and migrate away upon collision. Since then, we have gleaned little understanding of how contact inhibition is regulated and only lately observed its occurrence in vivo. We recently revealed that Drosophila macrophages (haemocytes) require contact inhibition for their uniform embryonic dispersal. Here, to investigate the role that contact inhibition plays in the patterning of haemocyte movements, we have mathematically analysed and simulated their contact repulsion dynamics. Our data reveal that the final pattern of haemocyte distribution, and the details and timing of its formation, can be explained by contact inhibition dynamics within the geometry of the Drosophila embryo. This has implications for morphogenesis in general as it suggests that patterns can emerge, irrespective of external cues, when cells interact through simple rules of contact repulsion.

Bayesian localization microscopy reveals nanoscale podosome dynamics.

We describe a localization microscopy analysis method that is able to extract results in live cells using standard fluorescent proteins and xenon arc lamp illumination. Our Bayesian analysis of the blinking and bleaching (3B analysis) method models the entire dataset simultaneously as being generated by a number of fluorophores that may or may not be emitting light at any given time. The resulting technique allows many overlapping fluorophores in each frame and unifies the analysis of the localization from blinking and bleaching events. By modeling the entire dataset, we were able to use each reappearance of a fluorophore to improve the localization accuracy. The high performance of this technique allowed us to reveal the nanoscale dynamics of podosome formation and dissociation throughout an entire cell with a resolution of 50 nm on a 4-s timescale.

Fixed pattern noise in localization microscopy.

Localization microscopy vastly improves the resolution achieved by fluorescence microscopy by fitting the positions of individual fluorophores. We examine the reconstructions produced by different fitting algorithms for instances of fixed pattern noise--systematic tendencies to alter estimated emitter positions according to their subpixel location in a way that does not reflect the ground truth structure. We show that while not readily visible at standard empirical signal strengths, fixed pattern noise can occur when performing sub-pixel fitting, and that its degree varies according to the algorithm used and the relative size of the pixels compared to the point spread function. For pixel sizes in the range 80-170 nm, this results in variations in accuracy of the order of 2-4 nm-comparatively small for many applications, but non-negligible in scenarios where very high accuracy is sought.

Urban rats are the 'fall-guy': Resident motivations for municipal rat complaints.

Rats are an important issue in cities globally. Despite their ubiquity, perceptions and concerns about rats vary with circumstance and the context in which a person interacts with them. Municipal rat management programs are a service to communities and therefore must be responsive to the varied concerns of their residents. Understanding why communities are concerned about rats can help inform rat management programs to meet the specific needs of their residents. The objective of this study was to identify why the residents of Vancouver, Canada care about rats and what they want done to address them. To do this, we qualitatively analyzed 6,158 resident complaints about rats made to the city's municipal government between January 2014 and May 2020. Using a qualitative descriptive coding process, we found that rats were a priority in a minority of cases. In general, people were more concerned about broader community issues, such as neighborhood disorder, of which rats were one part. Complaints tended to be made when problems were highly visible, nearby, and when the complainant wanted the city to take action to alleviate this issue, particularly when they were in and around their living spaces. The rates of complaints were highest in the most economically and socially deprived neighborhoods and lowest in the most privileged neighbourhoods. We synthesize this information with a view towards understanding how to develop objectives and actions for municipal management strategies that are grounded in community concerns.

'Misdiagnosed and Misunderstood': Insights into Rarer Forms of Dementia through a Stepwise Approach to Co-Constructed Research Poetry.

This study investigated co-constructed research poetry as a way to understand the lived experiences of people affected by rarer dementia and as a means to use poetry to convey those experiences to healthcare professionals. Using mixed methods, 71 people living with rarer dementia and care-partners (stakeholders) contributed to co-constructing 27 poems with professional poets; stakeholders' verbatim words were analysed with descriptive qualitative analysis. Stakeholders were also surveyed and interviewed about their participation. Healthcare professionals (n = 93) were surveyed to elicit their responses to learning through poetry and its acceptability as a learning tool. Poems conveyed a shared narrative of different aspects of lived experience, often owing to atypical symptoms, misunderstandings by professionals, lack of support pathways, and a continuous struggle to adapt. Stakeholder surveys indicated it was a valuable experience to both co-create and respond to the poems, whilst group interviews revealed people's experiences of the research poetry were characterised by reflection on lived experience, curiosity and exploration. Healthcare professionals' responses reinforced poetry's capacity to stimulate cognitive and affective learning specific to rare dementia support and prompt both empathy and critical thinking in practice. As the largest poetry-based study that we are aware of, this novel accessible approach of creating group poems yielded substantial information about the experiences and needs of those affected by rarer dementia and how poetry can contribute to healthcare education and training.