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Davenport N.R.,Cellular and Molecular Biology | Sonnemann K.J.,Laboratory of Cell and Molecular Biology | Eliceiri K.W.,Laboratory of Cell and Molecular Biology | Eliceiri K.W.,Laboratory for Optical and Computational Instrumentation | And 3 more authors.
Molecular Biology of the Cell

Cells rapidly reseal after damage, but how they do so is unknown. It has been hypothesized that resealing occurs due to formation of a patch derived from rapid fusion of intracellular compartments at the wound site. However, patching has never been directly visualized. Here we study membrane dynamics in wounded Xenopus laevis oocytes at high spatiotemporal resolution. Consistent with the patch hypothesis, we find that damage triggers rampant fusion of intracellular compartments, generating a barrier that limits influx of extracellular dextrans. Patch formation is accompanied by compound exocytosis, local accumulation and aggregation of vesicles, and rupture of compartments facing the external environment. Subcellular patterning is evident as annexin A1, dysferlin, diacylglycerol, active Rho, and active Cdc42 are recruited to compartments confined to different regions around the wound. We also find that a ring of elevated intracellular calcium overlaps the region where membrane dynamics are most evident and persists for several minutes. The results provide the first direct visualization of membrane patching during membrane repair, reveal novel features of the repair process, and show that a remarkable degree of spatial patterning accompanies damage-induced membrane dynamics. © 2016 van Gent and Kanaar. Source

Ittmann M.,Baylor College of Medicine | Ittmann M.,Michael bakey Veterans Affairs Medical Center | Huang J.,University of California at Los Angeles | Radaelli E.,University of Milan | And 15 more authors.
Cancer Research

Animal models, particularly mouse models, play a central role in the study of the etiology, prevention, and treatment of human prostate cancer. While tissue culture models are extremely useful in understanding the biology of prostate cancer, they cannot recapitulate the complex cellular interactions within the tumor microenvironment that play a key role in cancer initiation and progression. The National Cancer Institute (NCI) Mouse Models of Human Cancers Consortium convened a group of human and veterinary pathologists to review the current animal models of prostate cancer and make recommendations about the pathologic analysis of these models. More than 40 different models with 439 samples were reviewed, including genetically engineered mouse models, xenograft, rat, and canine models. Numerous relevant models have been developed over the past 15 years, and each approach has strengths and weaknesses. Analysis of multiple genetically engineered models has shown that reactive stroma formation is present in all the models developing invasive carcinomas. In addition, numerous models with multiple genetic alterations display aggressive phenotypes characterized by sarcomatoid carcinomas and metastases, which is presumably a histologic manifestation of epithelial-mesenchymal transition. The significant progress in development of improved models of prostate cancer has already accelerated our understanding of thecomplex biology of prostate cancer andpromises to enhance developmentof new approaches to prevention, detection, and treatment of this common malignancy. Cancer Res; 73(9); 2718-36. © 2013 AACR. Source

Freeman B.T.,University of Minnesota | Ogle B.M.,Laboratory for Optical and Computational Instrumentation | Ogle B.M.,University of Minnesota | Ogle B.M.,University of Wisconsin - Madison
Stem Cells Translational Medicine

Evidence suggests that transplanted mesenchymal stem cells (MSCs) can aid recovery of damaged myocardium caused by myocardial infarction. One possible mechanism for MSC-mediated recovery is reprogramming after cell fusion between transplanted MSCs and recipient cardiac cells. We used a Cre/LoxP-based luciferase reporter system coupled to biophotonic imaging to detect fusion of transplanted human pluripotent stem cell-derived MSCs to cells of organs of living mice. Human MSCs, with transient expression of a viral fusogen, were delivered to the murine heart via a collagen patch. At 2 days and 1 week later, living mice were probed for bioluminescence indicative of cell fusion. Cell fusion was detected at the site of delivery (heart) and in distal tissues (i.e., stomach, small intestine, liver). Fusion was confirmed at the cellular scale via fluorescence in situ hybridization for human-specific and mouse-specific centromeres. Human cells in organs distal to the heart were typically located near the vasculature, suggesting MSCs and perhaps MSC fusion products have the ability to migrate via the circulatory system to distal organs and engraft with local cells. The present study reveals previously unknown migratory patterns of delivered human MSCs and associated fusion products in the healthy murine heart. The study also sets the stage for follow-on studies to determine the functional effects of cell fusion ina model of myocardial damage or disease. © AlphaMed Press 2015. Source

Velten A.,Laboratory for Optical and Computational Instrumentation | Velten A.,Morgridge Institute for Research | White J.G.,Laboratory for Optical and Computational Instrumentation | Mackie T.R.,Morgridge Institute for Research | Eliceiri K.W.,Morgridge Institute for Research
CLEO: Applications and Technology, CLEO_AT 2013

Improved spectral resolution in confocal microscopy is important in both materials research and biological studies. When studying dynamic fluorescent samples, it is ideal to image at high spectral resolution while retaining good viability and signal sensitivity, as well as high temporal fidelity. We present a high-speed spectral confocal microscope that utilizes a low-loss Amici prism for spectral separation in conjunction with a multi-point confocal design for high-speed image capture. Our system achieves 15 channels of spectral resolution at a 2 frames per second imaging rate and with minimal loss of overall signal. © 2013 Optical Society of America. Source

Gehler S.,Augustana College at Rock Island | Ponik S.M.,University of Wisconsin - Madison | Ponik S.M.,Laboratory for Optical and Computational Instrumentation | Riching K.M.,Laboratory for Optical and Computational Instrumentation | And 3 more authors.
Critical Reviews in Eukaryotic Gene Expression

Cell transformation and tumor progression involve a common set of acquired capabilities, including increased proliferation, failure of cell death, self-sufficiency in growth, angiogenesis, and tumor cell invasion and metastasis. The stromal environment consists of many cell types and various extracellular matrix (ECM) proteins that support normal tissue maintenance and which have been implicated in tumor progression. Both the chemical and mechanical properties of the ECM have been shown to influence normal and malignant cell behavior. For instance, mesenchymal stem cells differentiate into specific lineages that are dependent on matrix stiffness, while tumor cells undergo changes in cell behavior and gene expression in response to matrix stiffness. ECM remodeling is implicated in tumor progression and can result in increased deposition of stromal ECM, enhanced contraction of ECM fibrils, and altered collagen alignment and ECM stiffness. Tumor cells respond to changes in ECM remodeling through altered intracellular signaling and cell cycle control that lead to enhanced proliferation, loss of normal tissue architecture, and local tumor cell migration and invasion. This review focuses on the bi-directional interplay between the mechanical properties of the ECM and integrin-mediated signal transduction events in an effort to elucidate cell behaviors during tumor progression. © 2013 Begell House, Inc. Source

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