The Importance of Model Systems

Animal models of autism, including cell based models, have received criticism because autism is a uniquely human condition so there is no value in studying it in a model like a mouse or a cell. On the other hand, model systems have been used for decades to develop therapies for a myraid of other conditions and disorders, and produced evidence-based treatments for not just autism but conditions from ADHD to schizophrenia. So why is there so much backlash about this line of research? The ASF podcast talks to Jill Silverman at UC Davis to get some perspective.

https://pubmed.ncbi.nlm.nih.gov/35285132

https://www.vox.com/future-perfect/377739/autism-research-mice-lab-models

More about the environmental influences in autism

New research points to a previously understudied but fascinating mechanism by which environmental factors may lead to autism: it’s called the “GABA/glutamate switch” which is a critical period in development when certain cells turn from turning on cell activity to turning them off. These environmental factors may delay this process leading to long term effects on the developing brain consistent with autism. While this data on the mechanism is brand new, the topic of the environment in autism was inspired by a recent effort at NIEHS which is developing an interactive database for people to access information about what environmental exposures have been studied and how in autism.

https://www.niehs.nih.gov/news/events/aware

https://www.pnas.org/doi/epub/10.1073/pnas.2406928121

Research for the end of Autism Action Month

In honor of the last week of Autism Awareness/Acceptance Month, we review two new scientific findings that call for more awareness and action, and less acceptance of the status quo. First: sex differences in autism are not well understood, and as it turns out, the influences on a diagnosis are different. Males have a higher rate of heritability compared to females. Second, those with rare genetic disorders have very few options for treatment, but a new study promises hope for more personalized approaches. The researchers use Timothy Syndrome as an example of how cells can start to function properly through a targeted approach which focuses on a small part of a gene. This is potentially life saving for individuals with this disorder.

https://www.ncbi.nlm.nih.gov/pmc/articles/pmid/38630491/

https://www.nature.com/articles/s41586-024-07310-6

How do you solve a problem like aggression?

Irritability and aggression are dangerous behaviors that can lead to harm and injury and are overlooked in research. Unfortunately there are only two FDA medications approved to treat them in autism. The drugs have many side effects, and there are efforts to improve these treatments and minimize side effects by lowering the dose with adjunct therapies that enhance the efficacy of the drug. So far, there are a few promising leads, but nothing that is ready for the clinic. How do scientists make the move from an interesting discovery in a lab to testing the safety and efficacy of a drug? Through animal models or model systems that examine different phenotypes in an animal and test medications on outcomes like aggression. Mice are not people, but they are necessary to ensure safe and effective treatments are translated into practice.

https://pubmed.ncbi.nlm.nih.gov/38263251/

The ASF Year End Review of Science

Just three days before 2024, ASF provides a summary of the the highlights of scientific discoveries and how they have translated into tools families can use. They include ways to speed up diagnosis and reduce waitlists, study of the brains in females and clinical recommendations for helping autistic females at birth, evidence of better practices around intervention and supports, and a review of the numbers of people who have a diagnosis. It isn’t comprehensive and if something was missed, our apologies, but the summary is 20 minutes.

You can read the text here: https://autismsciencefoundation.org/2023-year-end-review/

Animal models can explain heterogeneity

Just like no two people are the same, no two strains of mice are the same. Using dozens of different strains of mice with and without a genetic mutation associated with autism called CHD8, researchers at University of Southern California showed great variability in the effect of this mutation on behaviors associated with neurodevelopmental disorders. This can reflect the great differences across people with autism and even people with a rare genetic syndrome associated with autism. It isn’t just one gene, it’s the other hundreds of genes that can contribute to susceptibility or resilience to different features of NDDs. One thing this study did not do was overlay environmental factors, which will also significantly influence the variability seen across the different background genetics in these mice.

https://pubmed.ncbi.nlm.nih.gov/36738737/

Can animals be autistic?

The answer is obviously “no”, however, animal models are necessary to help understand brain circuitry and improve interventions and supports for not just core symptoms but associated issues like anxiety, OCD, seizures and GI issues. Scientists view behaviors consistent with an ASD diagnosis differently, and this has created some problems in interpretation of animal model data. This week’s #ASFpodcast will break down a recent paper in Genes, Brain and Behavior which addresses inconsistencies in the literature and makes recommendations on how researchers should shift how they think about how they can replicate features of ASD in a model system.

https://pubmed.ncbi.nlm.nih.gov/35285132/

Environmental factors as both causes and interventions?

Environmental exposures, including toxic chemicals, can contribute to the causes of ASD. But how do other environmental factors, like behavioral supports, work in the brain to improve behaviors associated with ASD? For this, you need a broad interpretation of the term “environmental” and an animal model so you can see the mechanism involved. Studies show while environmental factors can contribute, they can also provide modifications in cellular and molecular function which support learning and improved developmental trajectory. Finally, on a different topic, are autistic adults more likely to be involved in a crime compared to other groups? No, they are not, but there are factors which affect the risk of being involved with the criminal justice system, at least in the UK. Read more in the studies below.

https://pubmed.ncbi.nlm.nih.gov/34972219/

https://pubmed.ncbi.nlm.nih.gov/35259351/

https://pubmed.ncbi.nlm.nih.gov/35261275/

Ribbit…Ribbit… frogs are the new mouse of ASD research

You’ve heard a lot about CRISPR technology to manipulate gene expression. But what have scientists actually learned? Well, the cells in which DNA is manipulated could come from different animal models, including frogs and mice. These model systems are used to track brain development, sex differences, and the downstream effects of convergence of genetic manipulations of autism relevant genes on brain cells. They can be used, as one study demonstrated, to examine protective or resilience factors in the brain. This week we talk to Helen Willsey, PhD, at UCSF to hear about her research about manipulating genes in frog eggs and what it says about the female protective effect.

https://pubmed.ncbi.nlm.nih.gov/33497602/

https://pubmed.ncbi.nlm.nih.gov/33243861/

Happy New Year – reasons to be excited for 2021

Welcome to 2021! Over the holiday break, autism researchers were busy coming up with answers to important questions: 1) how does an environmental exposure relevant to ASD change gene expression and 2) does Telehealth work and for whom? The first question was addressed by an ASF undergraduate who published in Nature. He is going to go on to do great things.