Snapshot: What are Caenorhabditis elegans models?

What are C. elegans?

If you read the title of this article and had no idea what Caenorhabditis elegans are, you are not alone! Caenorhabditis elegans, more commonly known as C. elegans, are microscopic worms that typically grow up to 1 mm in length. C. elegans are naturally found worldwide in soil where there is rotting vegetation. If you are feeling brave, you can try to locate them in your household compost! Although these worms are less familiar to the general public, C. elegans are well known to scientists, since studying these tiny worms has taught us a lot about human disease.

Why are C. elegans used as a model system?

C. elegans were first isolated in 1900 and, since the late 1960s, have been used to “model” human disease. This is because C. elegans and humans share some common physiological features and have a significant overlap in their genetic codes. SCAsource previously published a Snapshot on mouse models, which are widely used in ataxia research,. Although C. elegans are not used as widely in ataxia research, there are many advantages to using C. elegans as a model system:

  • C. elegans are inexpensive to maintain, allowing for the screening of thousands of drugs at a relatively low cost. Once administered, scientists can study the drugs’ effects on C. elegans movement, development, and nervous system function.
  • C. elegans are easy to grow in the laboratory.
  • C. elegans are self-fertilizing hermaphrodites, meaning that they can reproduce without a sexual partner. A single hermaphrodite can produce 300-350 offspring over a 3-day period, allowing scientists to easily study a large number of worms that have the same genetic characteristics.
  • Scientists can easily manipulate the genome of C. elegans to study many human diseases.
  • Because C. elegans are transparent, their internal organs, including the nervous system, can be imaged without dissection.

How can C. elegans be used to study neurodegeneration?

The nervous system of a C. elegans is made up of a few hundred neurons, which is relatively simple compared to the human brain (which contains about 86 billion neurons). Because of this simplicity, scientists have used C. elegans to develop models for several neurodegenerative diseases, including Alzheimer’s, Parkinson’s, Friedreich’s ataxia and, more recently, spinocerebellar ataxia type III (SCA3). The SCA3 C. elegans model was developed by a research group in Portugal led by Dr. Patrícia Maciel, and it is the first of its kind in the spinocerebellar ataxia field. These worms express the human SCA3-causing protein in all their neurons, resulting in adult-onset motor dysfunction that resembles what we see in SCA3 patients.

a microscope image of neurons in two c. elegans worms. One is a smooth, healthy neuron. One has a damaged neuron that has a break in it.
A microscopy image of C. elegans neurons coloured green. Image courtesy of Kim Pho.

Neurodegeneration (damage/death of neurons) in C. elegans is monitored by tagging neurons with a marker that shines green under a specific type of light. The health of neurons is then assessed, making it possible to determine if neurodegeneration has occurred. The image above shows a healthy C. elegans neuron on the left, which appears intact, compared to a damaged C. elegans neuron on the right, which has a break (white arrowhead). Being able to distinguish between healthy and damaged neurons in C. elegans is very useful, as scientists can use this tool to test different ways of repairing or protecting neurons. If scientists are able to slow or prevent neurodegeneration in C. elegans, there is potential that such a discovery could eventually help treat human neurodegeneration, as well.

I hope this short summary has shown you that there is a massive amount of scientific potential in these tiny worms! Understanding the biology of C. elegans provides insight into human biology, like how neurodegeneration occurs and what we can do to stop it.

If you would like to learn more about C. elegans model systems, take a look at WormBook, Wormbase, and WormAtlas.

Thank you to Kim Pho from Dr. Lesley MacNeil’s lab at McMaster University for providing the fluorescent images of C. elegans neurons.

Snapshot written by Katie Graham and edited by Dr. Lesley MacNeil.

Working with cerebellar ataxia

Written by Dr. David Bushart Edited by Dr. Sriram Jayabal

How can employment be made more accessible for ataxia patients? What barriers exist? A study of workers and non-workers with ataxia analyzes the benefit of employment, as well as how to reduce risk of injury.

A job can often become part of a person’s identity. When people meet for the first time, one of the first questions that often comes up is “what do you do for work?” While this question can be harmless, it can also be frustrating to non-workers, particularly to those who are actively looking for employment. This may include some patients with cerebellar ataxia.

It can be difficult to manage disease symptoms alongside the stress of a job. However, some patients may find that including a job as part of their routine can be helpful for physical and mental wellness. In these cases, it is important for ataxia patients to have access to fair employment. Despite these benefits, finding a job can prove quite challenging, and unfortunately, ignorant assumptions about the capabilities of workers with ataxia may make finding employment even harder. How can employment be made more accessible to ataxia patients who wish to work?

two people shaking bands over a business agreement
Photo by fauxels on Pexels.com

Determining the work capabilities of ataxia patients

Helping ataxia patients find work might have a significant benefit on their overall quality-of-life. Researchers in Italy designed a study to get a better idea about the capabilities of workers with ataxia and the barriers to employment that they face. The research team, led by Alberto Ranavolo, interviewed both workers and non-workers with ataxia. Importantly, the patients interviewed for this study had been diagnosed with different types of ataxia, including dominantly-inherited ataxias, Friedrich’s ataxia, and other ataxias with unknown causes. Within this group, 24 were currently workers and 58 were non-workers at the time of the study. This allowed the researchers to determine how characteristics such as age, gender, education, and duration of symptoms might impact the ability to work.

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