An innovative tool allows researchers to observe protein aggregation throughout the life of a worm. The development of these aggregates, which play a role in the onset of a number of neurodegenerative diseases, can now be monitored automatically and in real time. This breakthrough was made possible by isolating worms in tiny microfluidic chambers developed at EPFL.
For rent: 32 individual rooms for a combined surface area of 4cm2, heating and food included! Biologists and microfluidics specialists at EPFL have joined forces and developed a highly innovative research tool: a 2cm by 2cm ‘chip’ with 32 independent compartments, each of which is designed to hold a nematode – a widely used worm in the research world. The device is described in the journal Molecular Neurodegeneration.
“Unlike conventional cultures in petri dishes, this device lets us monitor individual worms rather than a population of them,” said Laurent Mouchiroud, from EPFL’s Laboratory of Integrative Systems Physiology.
Freeze frame
Each of these ‘cells’ is fed by microfluidic channels. These allow variable concentrations of nutrients or therapeutic molecules to be injected with precision. The ambient temperature can also be adjusted.
Each worm is observed through a microscope throughout its life. However, for more detailed investigations and very high resolution images, the worms need to be immobilized. “For this we use a temperature-sensitive solution,” said Matteo Cornaglia, from the Laboratory of Microsystems. “We inject it in liquid form at 15°C, then bring the temperature up to 25°C, which transforms it into a gel. The worm is immobilized in just a few minutes, then we bring the temperature back down and rinse out the solution – and the worm is able to move again.”
Protein aggregates in the cross-hairs
This method is fully reversible and does not affect the nematode’s development. Using it, researchers can observe the formation of protein aggregates linked to several neurodegenerative diseases like Alzheimer’s, Parkinson’s and Huntington’s. The same worm can be photographed several times, as the clusters develop. “This is totally new, and it will help us learn more not only about how these aggregates grow, but also about the tissue in which they form,” said Mouchiroud. “In addition, we have already been able to test and observe the effect of certain drugs on how the clusters form.”
Nematodes are very useful models for studying a number of human diseases. In many cases, they obviate the need to experiment on rodents. But until now, handling nematodes was a delicate affair. By simplifying the process, this new technology should accelerate research on numerous afflictions and how they are treated.
Funding: This work was funded by the Canada Research Chairs program, the Graham Boeckh Foundation and the Natural Sciences and Engineering Research Council.
Source: Emmanuel Barraud – EPFL
Image Credit: The image is adapted from the EPFL press release.
Original Research: Full open access research for “Automated longitudinal monitoring of in vivo protein aggregation in neurodegenerative disease C. elegans models” by Matteo Cornaglia, Gopalan Krishnamani, Laurent Mouchiroud, Vincenzo Sorrentino, Thomas Lehnert, Johan Auwerx and Martin A. M. Gijs in Molecular Neurodegeneration. Published online February 9 2016 doi:10.1186/s13024-016-0083-6
Abstract
Automated longitudinal monitoring of in vivo protein aggregation in neurodegenerative disease C. elegans models
Background
While many biological studies can be performed on cell-based systems, the investigation of molecular pathways related to complex human dysfunctions – e.g. neurodegenerative diseases – often requires long-term studies in animal models. The nematode Caenorhabditis elegans represents one of the best model organisms for many of these tests and, therefore, versatile and automated systems for accurate time-resolved analyses on C. elegans are becoming highly desirable tools in the field.
Results
We describe a new multi-functional platform for C. elegans analytical research, enabling automated worm isolation and culture, reversible worm immobilization and long-term high-resolution imaging, and this under active control of the main culture parameters, including temperature. We employ our platform for in vivo observation of biomolecules and automated analysis of protein aggregation in a C. elegans model for amyotrophic lateral sclerosis (ALS). Our device allows monitoring the growth rate and development of each worm, at single animal resolution, within a matrix of microfluidic chambers. We demonstrate the progression of individual protein aggregates, i.e. mutated human superoxide dismutase 1 – Yellow Fluorescent Protein (SOD1-YFP) fusion proteins in the body wall muscles, for each worm and over several days. Moreover, by combining reversible worm immobilization and on-chip high-resolution imaging, our method allows precisely localizing the expression of biomolecules within the worms’ tissues, as well as monitoring the evolution of single aggregates over consecutive days at the sub-cellular level. We also show the suitability of our system for protein aggregation monitoring in a C. elegans Huntington disease (HD) model, and demonstrate the system’s ability to study long-term doxycycline treatment-linked modification of protein aggregation profiles in the ALS model.
Conclusion
Our microfluidic-based method allows analyzing in vivo the long-term dynamics of protein aggregation phenomena in C. elegans at unprecedented resolution. Pharmacological screenings on neurodegenerative disease C. elegans models may strongly benefit from this method in the near future, because of its full automation and high-throughput potential.
“Automated longitudinal monitoring of in vivo protein aggregation in neurodegenerative disease C. elegans models” by Matteo Cornaglia, Gopalan Krishnamani, Laurent Mouchiroud, Vincenzo Sorrentino, Thomas Lehnert, Johan Auwerx and Martin A. M. Gijs in Molecular Neurodegeneration. Published online February 9 2016 doi:10.1186/s13024-016-0083-6
