Renal complications of lipodystrophy: A closer look at the natural history of kidney disease

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/144612/1/cen13732_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/144612/2/cen13732.pd

PDMS filter structures for size-dependent larval sorting and on-chip egg extraction of C. elegans

C. elegans-based assays require age-synchronized populations prior to experimentation to achieve standardized sets of worm populations, due to which age-induced heterogeneous phenotyping effects can be avoided. There have been several approaches to synchronize populations of C. elegans at certain larval stages; however, many of these methods are tedious, complex and have low throughput. In this work, we demonstrate a polydimethylsiloxane (PDMS) microfluidic filtering device for high-throughput, efficient, and extremely rapid sorting of mixed larval populations of C. elegans. Our device consists of three plasma-activated and bonded PDMS parts and permits sorting of mixed populations of two consecutive larval stages in a matter of minutes. After sorting, we also retain the remaining larval stage of the initially mixed worm population on the chip, thereby enabling collection of the two sorted larval populations from the device. We demonstrated that the target larvae could be collected from a mixed worm population by cascading these devices. Our approach is based on only passive hydrodynamics filter structures, resulting in a user-friendly and reusable tool. In addition, we employed the equivalent of a standard bleaching procedure that is practiced in standard worm culture on agar plates for embryo harvesting on our chip, and we demonstrated rapid egg extraction and subsequent harvesting of a synchronized L1 larvae population

Automated high-content phenotyping from the first larval stage till the onset of adulthood of the nematode Caenorhabditis elegans

The nematode Caenorhabditis elegans is increasingly used as a model for human biology. However, in vivo culturing platforms for C. elegans allowing high-content phenotyping during their life cycle in an automated fashion are lacking so far. Here, a multiplexed microfluidic platform for the rapid high-content phenotyping of populations of C. elegans down to single animal resolution is presented. Nematodes are (i) reversibly and regularly confined during their life inside tapered channels for imaging fluorescence signal expression and to measure their growth parameters, and (ii) allowed to freely move in microfluidic chambers, during which the swimming behavior was video-recorded. The obtained data sets are analyzed in an automated way and 19 phenotypic parameters are extracted. Our platform is employed for studying the effect of bacteria dilution, a form of dietary restriction (DR) in nematodes, on a worm model of Huntington's disease and demonstrates the influence of DR on disease regression

Automated phenotyping of Caenorhabditis elegans embryos with a high-throughput-screening microfluidic platform

The nematode Caenorhabditis elegans has been extensively used as a model multicellular organism to study the influence of osmotic stress conditions and the toxicity of chemical compounds on developmental and motility-associated phenotypes. However, the several-day culture of nematodes needed for such studies has caused researchers to explore alternatives. In particular, C. elegans embryos, due to their shorter developmental time and immobile nature, could be exploited for this purpose, although usually their harvesting and handling is tedious. Here, we present a multiplexed, high-throughput and automated embryo phenotyping microfluidic approach to observe C. elegans embryogenesis after the application of different chemical compounds. After performing experiments with up to 800 embryos per chip and up to 12h of time-lapsed imaging per embryo, the individual phenotypic developmental data were collected and analyzed through machine learning and image processing approaches. Our proof-of-concept platform indicates developmental lag and the induction of mitochondrial stress in embryos exposed to high doses (200mM) of glucose and NaCl, while small doses of sucrose and glucose were shown to accelerate development. Overall, our new technique has potential for use in large-scale developmental biology studies and opens new avenues for very rapid high-throughput and high-content screening using C. elegans embryos. Microfluidics: High-throughput screening of embryosA new microfluidic approach enables the high-throughput and automated phenotyping of C. elegans embryos. Understanding the effect of osmotic stress-induced damage on cells is vital for understanding a number of biological processes. C. elegans embryos are considered ideal model systems for osmotic studies, but their phenotyping is traditionally a labor intensive and time-consuming process. Now, a team from EPFL in Switzerland led by Martin Gijs demonstrate a microfluidic platform for high-throughput phenotyping of C. elegans. Embryos are exposed to various osmotic compounds, followed by an automated phenotyping script to assess phenotypes via machine learning and image processing. Their proof of concept experiment demonstrates that their technique can be used for a systems-based approach for osmotic studies

Anin vivomicrofluidic study of bacterial transit inC. elegansnematodes

Caenorhabditis elegans(C. elegans) constitutes an important model organism for use in nutrition and aging studies. We report a novel method for studying the dynamics ofEscherichia coli(E. coli) bacterial transit through the worms' intestine. A microfluidic chip was designed for alternatingC. eleganson-chip culture and immobilization, thereby enabling periodic high-resolution time-lapse imaging at single-worm resolution over several days. Immobilization was achieved in a reversible way using arrays of tapered channels suitable for assay parallelization. DedicatedC. elegansfeeding protocols were applied. TwoE. colibacterial strains, HT115 and OP50, respectively labeled with green fluorescent protein (GFP) and red fluorescent protein (RFP), were used as food source and imaged with fluorescence microscopy techniques to measure relevant parameters of the bacterial transit process. Feeding behavior andE. colitransit dynamics in the whole intestinal tract of the worms were characterized in an automated way over the first 3 days of adulthood, revealing both fast transit phenomena and variations in microbial accumulation. In particular, we studied the bacterial food transit periodicity in wild-type andeat-2(ad465) mutantC. elegansstrains in both trapped and free-swimming conditions. In order to further demonstrate the versatility of our microfluidic platform, we also studied drug-induced modifications of the bacterial transit by measuring the response of the worms' intestine to exposure to the neurotransmitter serotonin

Massively Parallelized Pollen Tube Guidance and Mechanical Measurements on a Lab-on-a-Chip Platform

Pollen tubes are used as a model in the study of plant morphogenesis, cellular differentiation, cell wall biochemistry, biomechanics, and intra- and intercellular signaling. For a "systems-understanding" of the bio-chemo-mechanics of tip-polarized growth in pollen tubes, the need for a versatile, experimental assay platform for quantitative data collection and analysis is critical. We introduce a Lab-on-a-Chip (LoC) concept for high-throughput pollen germination and pollen tube guidance for parallelized optical and mechanical measurements. The LoC localizes a large number of growing pollen tubes on a single plane of focus with unidirectional tip-growth, enabling high-resolution quantitative microscopy. This species-independent LoC platform can be integrated with micro-/nano-indentation systems, such as the cellular force microscope (CFM) or the atomic force microscope (AFM), allowing for rapid measurements of cell wall stiffness of growing tubes. As a demonstrative example, we show the growth and directional guidance of hundreds of lily (Lilium longiflorum) and Arabidopsis (Arabidopsis thaliana) pollen tubes on a single LoC microscopy slide. Combining the LoC with the CFM, we characterized the cell wall stiffness of lily pollen tubes. Using the stiffness statistics and finite-element-method (FEM)-based approaches, we computed an effective range of the linear elastic moduli of the cell wall spanning the variability space of physiological parameters including internal turgor, cell wall thickness, and tube diameter. We propose the LoC device as a versatile and high-throughput phenomics platform for plant reproductive and development biology using the pollen tube as a model

Correction: Massively Parallelized Pollen Tube Guidance and Mechanical Measurements on a Lab-on-a-Chip Platform.

[This corrects the article DOI: 10.1371/journal.pone.0168138.]