Approaches to in vitro tissue regeneration with application for human disease modeling and drug development

Reliable in vitro human disease models that capture the complexity of in vivo tissue behaviors are crucial to gain mechanistic insights into human disease and enable the development of treatments that are effective across broad patient populations. The integration of stem cell technologies, tissue engineering, emerging biomaterials strategies and microfabrication processes, as well as computational and systems biology approaches, is enabling new tools to generate reliable in vitro systems to study the molecular basis of human disease and facilitate drug development. In this review, we discuss these recently developed tools and emphasize opportunities and challenges involved in combining these technologies toward regenerative science.National Institute for Biomedical Imaging and Bioengineering (U.S.) (Grant 5R01EB010246-02)National Center for Advancing Translational Sciences (U.S.) (Grant 1UH2TR000496)United States. Defense Advanced Research Projects Agency (Cooperative Agreement W911NF-12-2-0039

A microphysiological system model of therapy for liver micrometastases

Metastasis accounts for almost 90% of cancer-associated mortality. The effectiveness of cancer therapeutics is limited by the protective microenvironment of the metastatic niche and consequently these disseminated tumors remain incurable. Metastatic disease progression continues to be poorly understood due to the lack of appropriate model systems. To address this gap in understanding, we propose an all-human microphysiological system that facilitates the investigation of cancer behavior in the liver metastatic niche. This existing LiverChip is a 3D-system modeling the hepatic niche; it incorporates a full complement of human parenchymal and non-parenchymal cells and effectively recapitulates micrometastases. Moreover, this system allows real-time monitoring of micrometastasis and assessment of human-specific signaling. It is being utilized to further our understanding of the efficacy of chemotherapeutics by examining the activity of established and novel agents on micrometastases under conditions replicating diurnal variations in hormones, nutrients and mild inflammatory states using programmable microdispensers. These inputs affect the cues that govern tumor cell responses. Three critical signaling groups are targeted: the glucose/insulin responses, the stress hormone cortisol and the gut microbiome in relation to inflammatory cues. Currently, the system sustains functioning hepatocytes for a minimum of 15 days; confirmed by monitoring hepatic function (urea, α-1-antitrypsin, fibrinogen, and cytochrome P450) and injury (AST and ALT). Breast cancer cell lines effectively integrate into the hepatic niche without detectable disruption to tissue, and preliminary evidence suggests growth attenuation amongst a subpopulation of breast cancer cells. xMAP technology combined with systems biology modeling are also employed to evaluate cellular crosstalk and illustrate communication networks in the early microenvironment of micrometastases. This model is anticipated to identify new therapeutic strategies for metastasis by elucidating the paracrine effects between the hepatic and metastatic cells, while concurrently evaluating agent efficacy for metastasis, metabolism and tolerability.National Institutes of Health (U.S.) (Grant 1UH2TR000496-01)United States. Defense Advanced Research Projects Agency. Microphysiological Systems Program (W911NF-12-2-0039

Invasive annual grasses—Reenvisioning approaches in a changing climate

For nearly a century, invasive annual grasses have increasingly impacted terrestrial ecosystems across the western United States. Weather variability associated with climate change and increased atmospheric carbon dioxide (CO2) are making even more difficult the challenges of managing invasive annual grasses. As part of a special issue on climate change impacts on soil and water conservation, the topic of invasive annual grasses is being addressed by scientists at the USDA Agricultural Research Service to emphasize the need for additional research and future studies that build on current knowledge and account for (extreme) changes in abiotic and biotic conditions. Much research has focused on understanding the mechanisms underlying annual grass invasion, as well as assessing patterns and responses from a wide range of disturbances and management approaches. Weather extremes and the increasing occurrences of wildfire are contributing to the complexity of the problem. In broad terms, invasive annual grass management, including restoration, must be proactive to consider human values and ecosystem resiliency. Models capable of synthesizing vast amounts of diverse information are necessary for creating trajectories that could result in the establishment of perennial systems. Organization and collaboration are needed across the research community and with land managers to strategically develop and implement practices that limit invasive annual grasses. In the future, research will need to address invasive annual grasses in an adaptive integrated weed management (AIWM) framework that utilizes models and accounts for climate change that is resulting in altered/new approaches to management and restoration

Access to Adequate Outpatient Depression Care for Mothers in the USA: A Nationally Representative Population-Based Study

Maternal depression is often untreated, resulting in serious consequences for mothers and their children. Factors associated with receipt of adequate treatment for depression were examined in a population-based sample of 2,130 mothers in the USA with depression using data from the 1996–2005 Medical Expenditure Panel Survey. Chi-squared analyses were used to evaluate differences in sociodemographic and health characteristics by maternal depression treatment status (none, some, and adequate). Multivariate regression was used to model the odds of receiving some or adequate treatment, compared to none. Results indicated that only 34.8% of mothers in the USA with depression received adequate treatment. Mothers not in the paid workforce and those with health insurance were more likely to receive treatment, while minority mothers and those with less education were less likely to receive treatment. Understanding disparities in receipt of adequate treatment is critical to designing effective interventions, reducing treatment inequities, and ultimately improving the mental health and health of mothers and their families

Effects of the neurogranin variant rs12807809 on thalamocortical morphology in schizophrenia

10.1371/journal.pone.0085603PLoS ONE812-POLN

High-resolution three-dimensional reconstruction of a whole yeast cell using focused-ion beam scanning electron microscopy

We developed an approach for focused gallium-ion beam scanning electron microscopy with energy filtered detection of backscattered electrons to create near isometric voxels for high-resolution whole cell visualization. Specifically, this method allowed us to create three-dimensional volumes of high-pressure frozen, freeze-substituted Saccharomyces cerevisiae yeast cells with pixel resolutions down to 3 nm/pixel in x, y, and z, supported by both empirical data and Monte Carlo simulations. As a result, we were able to segment and quantify data sets of numerous targeted subcellular structures/organelles at high-resolution, including the volume, volume percentage, and surface area of the endoplasmic reticulum, cell wall, vacuoles, and mitochondria from an entire cell. Sites of mitochondrial and endoplasmic reticulum interconnectivity were readily identified in rendered data sets. The ability to visualize, segment, and quantify entire eukaryotic cells at high-resolution (potentially sub-5 nanometers isotropic voxels) will provide new perspectives and insights of the inner workings of cells

A liver microphysiological system of tumor cell dormancy and inflammatory responsiveness is affected by scaffold properties

Distant metastasis is the major cause of breast cancer-related mortality, commonly emerging clinically after 5 or more years of seeming 'cure'of the primary tumor, indicating a quiescent dormancy. The lack of relevant accessible model systems for metastasis that recreate this latent stage has hindered our understanding of the molecular basis and the development of therapies against these lethal outgrowths. We previously reported on the development of an all-human 3D ex vivo hepatic microphysiological system that reproduces several features of liver physiology and enables spontaneous dormancy in a subpopulation of breast cancer cells. However, we observed that the dormant cells were localized primarily within the 3D tissue, while the proliferative cells were in contact with the polystyrene scaffold. As matrix stiffness is known to drive inflammatory and malignant behaviors, we explored the occurrence of spontaneous tumor dormancy and inflammatory phenotype. The microphysiological system was retrofitted with PEGDa-SynKRGD hydrogel scaffolding, which is softer and differs in the interface with the tissue. The microphysiological system incorporated donor-matched primary human hepatocytes and non-parenchymal cells (NPCs), with MDA-MB-231 breast cancer cells. Hepatic tissue in hydrogel scaffolds secreted lower levels of pro-inflammatory analytes, and was more responsive to inflammatory stimuli. The proportion of tumor cells entering dormancy was markedly increased in the hydrogel-supported tissue compared to polystyrene. Interestingly, an unexpected differential response of dormant cells to varying chemotherapeutic doses was identified, which if reflective of patient pathophysiology, has important implications for patient dosing regimens. These findings highlight the metastatic microphysiological system fitted with hydrogel scaffolds as a critical tool in the assessment and development of therapeutic strategies to target dormant metastatic breast cancer