More Support for the use of Statins in some Autism

Monty, aged 12 with ASD, has been taking Atorvastatin for two years, with a clear cognitive improvement from day one.  

This improvement is lost when this therapy is interrupted.

There are several posts in this blog giving the scientific basis why statins might be beneficial in some autism, these included the genes/proteins RAS, PTEN and BCL2.  In addition, statins possess potent anti-inflammatory properties.

Following a flood of visits to this blog to read about statins and autism, I did a quick check and in recent weeks at least three papers have been published suggesting the potential for statins to improve some autism.

I include the word “some” because with 800 currently identified autism genes, and I expect eventually it will be thousands, what works for one person’s “autism” may not help the next person’s “autism” and might even make it worse.

The first paper is the one getting the media coverage, it is from the University of Edinburgh, plus Mark Bear et al from MIT.  Mark Bear’s lab has featured in this blog several times, particularly relating to Fragile-X.  Lovastatin is being already trialed in humans with Fragile-X.

I use Atorvastatin (Lipitor) because it has best side effect profile.  Lovastatin and Simvastatin will have the same effect.  In some countries these drugs are available cheaply OTC.

Their therapeutic effect in autism, based on my sample of one, is from the first pill.

Over to the "experts":-

Cholesterol drug could aid autism sufferers

Intellectual disabilities and autism spectrum disorders could share similar defects although their genetic causes are different, according to Scottish scientists.

A study of two models of intellectual disability in mice by Edinburgh University has found that they share similar disease mechanisms.

Researchers also found that treatment with a statin drug called Lovastatin, which is often used to treat high cholesterol, can correct high levels of protein production in the brain linked to the conditions.

The findings suggest that different types of intellectual disabilities may benefit from common therapeutic approaches, the researchers say.

Professor Peter Kind, Director of the University of Edinburgh’s Patrick Wild Centre for Research into Autism, Fragile X Syndrome and Intellectual Disabilities, said: “Statins, such as lovastatin, are already used widely for treating people, including children, for high cholesterol with minimal side effects.

“Further studies are needed to determine whether these existing medications could also help people with intellectual disabilities.”

The study has been published in the Journal of Neuroscience

The full paper is here:-

Convergence of Hippocampal Pathophysiology in Syngap+/− and Fmr1−/y Mice

Abstract

Previous studies have hypothesized that diverse genetic causes of intellectual disability (ID) and autism spectrum disorders (ASDs) converge on common cellular pathways. Testing this hypothesis requires detailed phenotypic analyses of animal models with genetic mutations that accurately reflect those seen in the human condition (i.e., have structural validity) and which produce phenotypes that mirror ID/ASDs (i.e., have face validity). We show that SynGAP haploinsufficiency, which causes ID with co-occurring ASD in humans, mimics and occludes the synaptic pathophysiology associated with deletion of the Fmr1 gene. Syngap^+/− and Fmr1^−/y mice show increases in basal protein synthesis and metabotropic glutamate receptor (mGluR)-dependent long-term depression that, unlike in their wild-type controls, is independent of new protein synthesis. Basal levels of phosphorylated ERK1/2 are also elevated in Syngap^+/− hippocampal slices. Super-resolution microscopy reveals that Syngap^+/− and Fmr1^−/y mice show nanoscale alterations in dendritic spine morphology that predict an increase in biochemical compartmentalization. Finally, increased basal protein synthesis is rescued by negative regulators of the mGlu subtype 5 receptor and the Ras–ERK1/2 pathway, indicating that therapeutic interventions for fragile X syndrome may benefit patients with SYNGAP1 haploinsufficiency.

SIGNIFICANCE STATEMENT As the genetics of intellectual disability (ID) and autism spectrum disorders (ASDs) are unraveled, a key issue is whether genetically divergent forms of these disorders converge on common biochemical/cellular pathways and hence may be amenable to common therapeutic interventions. This study compares the pathophysiology associated with the loss of fragile X mental retardation protein (FMRP) and haploinsufficiency of synaptic GTPase-activating protein (SynGAP), two prevalent monogenic forms of ID. We show that Syngap^+/− mice phenocopy Fmr1^−/y mice in the alterations in mGluR-dependent long-term depression, basal protein synthesis, and dendritic spine morphology. Deficits in basal protein synthesis can be rescued by pharmacological interventions that reduce the mGlu₅ receptor–ERK1/2 signaling pathway, which also rescues the same deficit in Fmr1^−/y mice. Our findings support the hypothesis that phenotypes associated with genetically diverse forms of ID/ASDs result from alterations in common cellular/biochemical pathways.

The other two papers are from 2015 Society for Neuroscience annual meeting in Chicago.

  

Experimental cancer drug eases autism symptoms in mice

A drug that blocks a cancer-related pathway normalizes neuron number and prevents behavior problems in mice that lack a copy of the autism-linked chromosomal region 16p11.2. Researchers presented the unpublished results yesterday at the 2015 Society for Neuroscience annual meeting in Chicago.

Loss of 16p11.2 results in intellectual disability, enlarged head, obesity and, often, autism. This region spans 27 genes — including one called ERK1, part of a signaling cascade that regulates cell growth. The cascade, called the RAS pathway, is hyperactive in some types of cancer and in four rare autism-linked neurodevelopmental disorders, collectively dubbed ‘RASopathies.’ The proteins encoded by ERK1 and the related ERK2 gene carry out many of the molecular consequences of RAS pathway activation.

Paradoxically, the ERK proteins are hyperactive in mice lacking a copy of 16p11.2¹. This hyperactivation coincides with a period of intense neuron development in the mouse embryo. The animals also have too few neurons in some parts of the cerebral cortex, the brain’s outer layer, and too many neurons in others.

“Because of this aberrant ERK hyperactivity, we were thinking that we can potentially try to bring the levels down by using a specific ERK inhibitor,” says Joanna Pucilowska, a postdoctoral fellow in Gary Landreth’s lab at Case Western Reserve University in Cleveland, Ohio.

Sniffing clues:

Pucilowska and her colleagues used an experimental drug that blocks activation of the ERK proteins. They injected the drug into pregnant mice to investigate its effects on neuron development in mouse embryos.

Treating mice with the drug prenatally for five days stabilizes ERK activity, the researchers found. It also normalizes neuron numbers in the cerebral cortex.

The treatment has lasting effects on behavior, too. Unlike untreated mice that lack a copy of 16p11.2 — which are underweight, hyperactive and have memory problems — the treated mice resemble those that do not have the chromosomal deletion.

The researchers discovered for the first time that mice lacking 16p11.2 are quicker than those without the deletion to sniff out a hidden snack in their cage, suggesting they have a highly acute sense of smell, like some people missing 16p11.2. Female mice with the deletion are also faster to retrieve pups that stray from the safety of their nest, an innate maternal behavior. The drug treatment normalizes both behaviors.

Pucilowska says she and her colleagues would like to test the drug in cells derived from people missing a copy of 16p11.2. If it works in human cells the same way it does in mice, then it might be possible to treat people with the deletion using cholesterol-lowering drugs called statins, which are also known to block signaling in the RAS pathway. “This can potentially lead to the first treatment for children with 16p11.2 deletion,” Pucilowska says.

Autism model reveals brain processes behind ‘super’ skills

Structural changes in the connections between neurons may underlie the enhanced learning and motor skills seen in mice with an extra copy of the autism-linked gene MeCP2. Blocking these changes with a drug blunts the animals’ performance.

The findings, presented yesterday at the 2015 Society for Neuroscience annual meeting in Chicago, point to neural mechanisms underlying the restricted interests and, in some cases, exceptional learning abilities seen in people with autism.

“This could lead to enhanced learning and enhanced performance in constrained behaviors, like in autistic savants,” says Ryan Ash, a graduate student in Stelios Smirnakis’ lab at Baylor College of Medicine in Houston. “Maybe they can’t iteratively refine those kinds of behaviors over time, so they get stuck in a behavior, which can be exceptional in certain cases but then impaired in others.”

People carrying an extra copy of MeCP2 often have autism. Mice with the same duplication have autism-like symptoms, such as avoiding social interactions with other mice.

“But they also have a super-learner phenotype,” Ash says. They perform better than controls do on a test of motor skill learning that involves balancing on a rotating rod. Typical mice fall off the rod as its speed increases, but mice with the duplication learn to coordinate their feet so that they can stay on about 30 seconds longer.

When mice learn a motor task, new synapses, connections between neurons, form in the brain¹. The researchers suspected that the superior learning abilities of the mice carrying the extra MeCP2 might stem from alterations in the formation and stability of these neuronal links.

To test this hypothesis, the researchers used microscopy to image neurons in the brain that connect to the spinal cord and control movement. They took pictures of the same neurons before and after the mice practiced the rotating rod test for four days, and again after the animals had four days of rest.

Spine support:

As expected, training spurred neurons in typical mice to form new signal-receiving projections, called dendritic spines. About half of these spines remained after four days of rest, suggesting the formation of stable memories. Mutant mice form more spines than controls do, and more of them stay put after the mice take a break.

The stable spines tend to cluster. Enhanced performance on the rod tracks with a greater number of clustered spines remaining after the rest period.

“We think this is important because spines that are near each other can drive the cell more strongly when they get activated at the same time,” Ash says.

Training stimulates greater activation of a signaling cascade called the RAS pathway in the mutant mice than it does in controls. Activation of this pathway is known to strengthen clustered spines².

Blocking the activation of this pathway with an experimental drug called SL327 lowers the mutants’ performance on the rotating rod back to the normal range. And the spines in these animals also look more like those of typical mice.

The findings suggest that spine formation and stability underlie the enhanced learning abilities of the mutant mice. Both processes appear to depend on the activation of the RAS pathway.

The drug the researchers used lasts only for a few hours, so it is not likely to help people with autism, Ash says. But cholesterol-lowering drugs called statins block activation of the same pathway by a different mechanism. “Maybe you could do a more chronic treatment with a statin, but we haven’t tried that yet,” he says.

Other mouse models of autism show enhanced performance on the rotating rod test. These include mice with a duplication in chromosomal region 15q11-13 and with mutations in the CNTNAP2, NLGN3 and NRXN1 genes, Ash says.

Interestingly, mice that lack a copy of MeCP2 — the gene mutated in the autism-linked disorder Rett syndrome — have impaired performance on the same test, and show reduced spine stability. “I would hypothesize that all of these things are actually the opposite in the Rett mice,” Ash says.