Explore the vast range of titles available.

In native states, animal cells of many types are supported by a fibrous network that forms the main structural component of the ECM. Mechanical interactions between cells and the 3D ECM critically regulate cell function, including growth and migration. However, the physical mechanism that governs the cell interaction with fibrous 3D ECM is still not known. In this article, we present single-cell traction force measurements using breast tumor cells embedded within 3D collagen matrices. We recreate the breast tumor mechanical environment by controlling the microstructure and density of type I collagen matrices. Our results reveal a positive mechanical feedback loop: cells pulling on collagen locally align and stiffen the matrix, and stiffer matrices, in return, promote greater cell force generation and a stiffer cell body. Furthermore, cell force transmission distance increases with the degree of strain-induced fiber alignment and stiffening of the collagen matrices. These findings highlight the importance of the nonlinear elasticity of fibrous matrices in regulating cell–ECM interactions within a 3D context, and the cell force regulation principle that we uncover may contribute to the rapid mechanical tissue stiffening occurring in many diseases, including cancer and fibrosis.

Biomaterial scaffolds mimicking the environment in metastatic organs can deconstruct complex signals and facilitate the study of cancer progression and metastasis. Here we report that a subcutaneous scaffold implant in mouse models of metastatic breast cancer in female mice recruits lung-tropic circulating tumor cells yet suppresses their growth through potent in situ antitumor immunity. In contrast, the lung, the endogenous metastatic organ for these models, develops lethal metastases in aggressive breast cancer, with less aggressive tumor models developing dormant lungs suppressing tumor growth. Our study reveals multifaceted roles of neutrophils in regulating metastasis. Breast cancer-educated neutrophils infiltrate the scaffold implants and lungs, secreting the same signal to attract lung-tropic circulating tumor cells. Second, antitumor and pro-tumor neutrophils are selectively recruited to the dormant scaffolds and lungs, respectively, responding to distinct groups of chemoattractants to establish activated or suppressive immune environments that direct different fates of cancer cells. 3D scaffolds can be used to recapitulate key aspects of the microenvironment of primary tumors and metastatic organs. Here the authors use subcutaneous porous 3D scaffold implants as a tool to study the immune signals in the lungs of metastatic breast cancer, revealing multifaceted roles of neutrophils in regulating lung metastasis.

Introduction Natural killer (NK) cell-based therapies are a promising new method for treating indolent cancer, however engineering new therapies is complex and progress towards therapy for solid tumors is slow. New methods for determining the underlying intracellular signaling driving the killing phenotype would significantly improve this progress. Methods We combined single-cell RNA sequencing with live cell imaging of a model system of NK cell killing to correlate transcriptomic data with functional output. A model of NK cell activity, the NK-92 cell line killing of HeLa cervical cancer cells, was used for these studies. NK cell killing activity was observed by microscopy during co-culture with target HeLa cells and killing activity subsequently manually mapped based on NK cell location and Annexin V expression. NK cells from this culture system were profiled by single-cell RNA sequencing using the 10× Genomics platform, and transcription factor activity inferred using the Viper and DoRothEA R packages. Luminescent microscopy of reporter constructs in the NK cells was then used to correlate activity of inferred transcriptional activity with killing activity. Results NK cells had heterogeneous killing activity during 10 h of culture with target HeLa cells. Analysis of the single cell sequencing data identified Nuclear Factor Kappa B (NF-κB), Signal Transducer and Activator of Transcription 1 (STAT1) and MYC activity as potential drivers of NK cell functional phenotype in our model system. Live cell imaging of the transcription factor activity found NF-κB activity was significantly correlated with past killing activity. No correlation was observed between STAT1 or MYC activity and NK cell killing. Conclusions Combining luminescent microscopy of transcription factor activity with single-cell RNA sequencing is an effective means of assigning functional phenotypes to inferred transcriptomics data.

. The receptor of epidermal growth factor (EGFR) critically regulates tumor cell invasion and is a potent therapeutic target for treatment of many types of cancers, including carcinomas and glioblastomas. It is known that EGF regulates cell motility when tumor cells are embedded within a 3D biomatrix. However, roles of EGF in modulating tumor cell motility phenotype are largely unknown. In this article, we report that EGF promotes a mesenchymal over an amoeboid motility phenotype using a malignant breast tumor cell line, MDA-MB-231, embedded within a 3D collagen matrix. Amoeboid cells are rounded in shape, while mesenchymal cells are elongated, and their migrations are governed by a distinctly different set of biomolecules. Using single cell tracking analysis, we also show that EGF promotes cell dissemination through a significant increase in cell persistence along with a moderate increase of speed. The increase of persistence is correlated with the increase of the percentage of the mesenchymal cells within the population. Our work reveals a novel role of microenvironmental cue, EGF, in modulating heterogeneity and plasticity of tumor cell motility phenotype. In addition, it suggests a potential visual cue for diagnosing invasive states of breast cancer cells. This work can be easily extended beyond breast cancer cells.

Conspiracy theories (CTs) appear to be an increasingly widespread aspect of everyday thought about social and political events. They call into question common understandings of people and institutions within society, and can have implications for political and policy relevant behaviours (e.g. voting, vaccine uptake). This thesis challenges a central finding in the limited literature covering belief in CTs – the proposition of ‘monologicality’ as proposed by Goertzel (1994), that belief in one CT is accompanied by wholescale endorsement of many others. The thesis takes a mixed-methods approach, triangulating qualitative and quantitative data, to revise our understanding of monologicality. Through qualitative analyses of interview data as presented in Chapters 2, 3 and 4, the central argument put forward is that not all belief in CTs is monological but there are various other ways of endorsing CTs. In Chapter 2, a thematic analysis reveals five types of conspiracist worldviews, proposing a gradient from non-monological worldviews, characterised by intrigue or limited endorsement, to fully monological worldviews premised upon generalised human agency (e.g. government conspiracy) or supernatural agency (e.g. extra-terrestrial cover up, spiritual entities). Chapter 3 advances the concept of ‘dialogicality,’ revealing that CT ideas are endorsed alongside commonplace ideas of science, religion and politics and society. Five dialogical relations are substantiated, including: integrative thinking, synthetic thinking, target dependent thinking, cognitive dissonance and analogical thinking. Chapter 4 provides a narrative insight into the development of CT belief for all five monological types – focussing on the perceived origins of CT belief and later development. Next, we turn to quantitative data gathered via online surveys. Chapter 5 establishes a new scale known as the Conspiracist Worldviews Scale; the first to measure different types of conspiracist worldviews from non-monological to fully 5 monological. Five subscales representing five types of conspiracist worldviews (Type 2, Type 3, Type 4, Type 5-Alien, Type 5-Spiritual) achieve construct, convergent, concurrent and diagnostic validity. The quantitative findings of Chapter 5 validate earlier qualitative findings of Chapters 2-4 and extend previous understandings of monologicality. The thesis concludes, bringing all these empirical findings together and by recognising the importance of looking beyond monologicality if we are to fully understand the phenomena characterising conspiracist belief.

Pre-metastatic niches in distant tissue facilitate metastasis from the primary tumor. Cargo-free porous polymer scaffolds implanted in tumor-bearing mice act as synthetic metastatic niches recruiting metastasizing cancer cells. Herein, we investigated the mechanisms by which these implants attract cancer cells from circulation. Scaffolds attract cancer cells in part via S100A8/A9 secreted by Gr1+ myeloid cells in a mechanism that mimics lung metastasis. Further, cancer cells attracted to the scaffold have a lung-tropic gene expression signature regardless of their tissue of origin. The scaffold implant reduces metastasis to the lung suggesting otherwise lung-tropic cancer cells are diverted to the scaffold. The suppression of metastatic spread by the scaffold suggests this mechanism may be exploited for novel therapies, and may broadly influence the design of scaffold-based drug delivery system for anti-cancer therapy.

As the immigrant population in the U.S. swells in size and expands across the geographic landscape, virtually every aspect of contemporary social life is being transformed, influencing natives' job prospects, the challenges faced by local schools, and America's ethnic mix and cultural identity. These and other issues are closely related to immigrant settlement patterns across U.S. neighborhoods. Understanding immigrants' imprint on the residential landscape is thus central to broader debates over how immigration impacts American life and how immigrants fare in their new home. This dissertation seeks to address this important topic by providing a detailed, yet comprehensive account of new immigrants' residential circumstances. Specifically, I use neighborhood-level data from Census 2000 and household-level data from the American Housing Survey to explore patterns and correlates of residential segregation and attainment for ten new immigrant groups. In sum, I find that the assimilation of new immigrants is clearly underway: Greater socioeconomic resources and acculturation are associated with greater proximity to native-born whites, lower residential isolation, higher-quality housing, and better neighborhoods. On the other hand, my research also points to a rigid racial/ethnic pattern with Asian immigrants being less segregated and occupying superior housing and neighborhood environments than Latin American and Caribbean immigrants. The extraordinarily high levels of segregation for black immigrants are especially disturbing and indicate the continued relevance of the principle of black exceptionalism. I also show that the fairly high levels of immigrant group segregation in established metropolitan areas are being reproduced in new and nongateway metropolitan destinations. Despite some of these troubling patterns, my analysis generally suggests that immigrant segregation does not translate into poor housing and neighborhood outcomes. While I do find that the odds of homeownership are lower for immigrants in segregated contexts, and that segregation is consistently detrimental for Mexican immigrants' residential attainment, segregation tends to have no effect or exerts positive ones on other measures of housing and neighborhood quality. All in all, this research points not just to the challenges faced by new arrivals in American residential life, but also to the clear signs that new immigrants are participating in the American Dream.

Biomaterial systems have allowed for the in vitro production of complex, emergent tissue behaviors that were not possible with conventional 2D culture systems allowing for analysis of the normal development as well as disease processes. We propose that the path towards developing the design parameters for biomaterial systems lies with identifying the molecular drivers of emergent behavior through leveraging technological advances in systems biology, including single cell omics, genetic engineering, and high content imaging. This research focus, which we term systems tissue engineering, can uniquely interrogate the mechanisms by which complex tissue behaviors emerge with the potential to capture the contribution of i) dynamic regulation of tissue development and dysregulation, ii) single cell heterogeneity and the function of rare cell types, and iii) the spatial distribution and structure of individual cells and cell types within a tissue. Collectively, systems tissue engineering can facilitate the identification of biomaterial design parameters that will accelerate basic science discovery and translation.

The mosquito Aedes aegypti is the primary vector of many disease-causing viruses, including dengue (DENV), Zika, chikungunya, and yellow fever. As consequences of climate change, we expect an increase in both global mean temperatures and extreme climatic events. When temperatures fluctuate, mosquito vectors will be increasingly exposed to temperatures beyond their upper thermal limits. Here, we examine how DENV infection alters Ae . aegypti thermotolerance by using a high-throughput physiological ‘knockdown’ assay modeled on studies in Drosophila . Such laboratory measures of thermal tolerance have previously been shown to accurately predict an insect’s distribution in the field. We show that DENV infection increases thermal sensitivity, an effect that may ultimately limit the geographic range of the virus. We also show that the endosymbiotic bacterium Wolbachia pipientis , which is currently being released globally as a biological control agent, has a similar impact on thermal sensitivity in Ae . aegypti . Surprisingly, in the coinfected state, Wolbachia did not provide protection against DENV-associated effects on thermal tolerance, nor were the effects of the two infections additive. The latter suggests that the microbes may act by similar means, potentially through activation of shared immune pathways or energetic tradeoffs. Models predicting future ranges of both virus transmission and Wolbachia’s efficacy following field release may wish to consider the effects these microbes have on host survival.