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Showing posts with label mTOR. Show all posts
Showing posts with label mTOR. Show all posts

Wednesday, 6 November 2019

Metformin to raise Cognition in Fragile X and some other Autisms?




I started to write this post a long time ago, when Agnieszka first highlighted an interview with Dr Hagerman from UC Davis.  Hagerman is experimenting in using Metformin to treat Fragile-X.

Having again be reminded about Metformin, I realized that I never finished my post on this subject. With some extras about autophagy and a nice graphic courtesy of Ling’s excellent paper, here it is. 

Metformin has already been covered in 5 previous posts.


One interesting point is that the researchers at UC Davis are using the measurement of IQ as one of the outcome measures in their trial of Metformin.  I have been suggesting the French Bumetanide researchers do this for a long time.

It is my opinion that simple medical interventions can have a profound impact on the IQ of some people with severe autism. I mean raising IQ not by 5-10 points as at UC Davis, but by 20-50 points.  IQ can be measured using standardized tools and is far less subjective than any autism rating scale.

The big-time potential IQ enhancers we have seen in this blog include: -

·        Bumetanide/Azosemide
·        Statins (Atorvastatin, Lovastatin, Simvastatin, but they are not equivalent and the effect has nothing to do with lowering cholesterol)
·        Micro-dose Clonazepam
·        Clemastine
·        It seems DMF, in n=2 trial

The good news is that these drugs are all off-patent cheap generics (except DMF), as is metformin.  No need for drugs costing $50,000 a year.

For those that do not know, metformin is the first line medication for type-2 diabetes. It was introduced as a medication in France in 1957 and the United States in 1995.  In many countries Metformin is extremely cheap, with 30 x 500 mg tablets costing about $2 or Eur 2. In the US it costs about $10 for generic, so not expensive. 

There are sound reasons why Metformin could increase IQ in someone with autism or Fragile-X. In the case of idiopathic autism is there a likely biomarker to identify a likely responder? One has not yet been identified.

Clearly Metformin will not work for all people with autism and MR/ID, but even if it only works for 10% that would be great.

Are all parents going to notice an increase in IQ of 5-10 points?  You might think so, but I doubt it.  I would hope therapists, teachers and assistants would notice.

I think basic mental maths is the best way to notice improved cognitive function in people with IQ less than 70.  You can easily establish a baseline and then you can notice/measure improvements.

Improved cognitive function does not just help with maths, it helps with learning basic skills like tying shoe laces, brushing teeth and later shaving.  This does also involve many other types of skill.





In the study, researchers from the UC Davis Medical Investigation of Neurodevelopmental Disorders Institute in California tested the long-term effects of metformin, delivered at 1,000 milligrams (mg) twice a day, for one year in two male patients, 25 and 30 years old. Genetic analysis confirmed that both patients had mutations in the FMR1 gene, confirming their fragile X syndrome diagnoses.

The younger patient had autism and was also diagnosed with generalized anxiety disorder. First prescribed metformin at 22, he is currently taking 500 mg of metformin twice a day and 10 mg per day of simvastatin — used to lower the level of cholesterol in the blood.
The second patient was also diagnosed with anxiety and exhibited socially nervous behaviors, including panic attacks. He had severe limitations in language use, and communicated in short sentences and by mumbling. He had been on an extended-release formulation of metformin, taking 1,000 mg once a day for one year.

Both patients showed significant cognitive and behavioral improvements. After one year of treatment with metformin, test results revealed an increase in the patients’ IQ scores, from 53 to 57 in the younger patient and from 50 to 58 in the second patient.

Verbal and nonverbal IQ — the ability to analyze information and solve problems using visual or hands-on reasoning — were also improved in both patients. Non-verbal IQ increased from 50 to 52 in the younger patient and from 47 to 51 in the other. Verbal IQ went from 61 to 66 in the first patient, and from 58 to 68 in the second.

                                                              

Researcher Randi Hagerman is a big proponent of metformin — a diabetes drug that helps people manage their weight. In fact, Hagerman takes the drug herself as a preventive measure against cancer.
Metformin has also unexpectedly shown promise for improving cognition in people with fragile X syndrome, a leading genetic cause of autism characterized by severe intellectual disability.

A study published in 2017 linked impaired insulin signalling in the brain to cognitive and social deficits in a fruit fly model of fragile X, and the flies improved on metformin. A second paper that year showed that metformin reverses abnormalities in a mouse model of the syndrome, including the number of branches the mice’s neurons form. It also improved seizures and hyperactivity in the mice — issues we also see in people with fragile X.
I began prescribing metformin to people with fragile X syndrome to help curb overeating. Many of the people I treat are overweight because of this habit — it’s one of the symptoms of a subtype of fragile X called the Prader-Willi phenotype, not to be confused with Prader-Willi syndrome.
I was surprised when the families of these individuals told me they could talk better and carry out conversations, where they couldn’t before. That really gave us impetus to conduct a controlled clinical trial.
It’s not a cure-all, but we do see some positive changes. It doesn’t resolve intellectual disability, but we have seen IQ improvements of up to 10 points in two boys who have been treated with metformin. We are very excited about that.

Individuals on metformin tend to start eating less, and often lose weight as a result. I could kick myself, because metformin has been approved to treat obesity for many years, but I never thought to use it in fragile X syndrome. Oftentimes children with fragile X syndrome have so many problems that you aren’t thinking about obesity as the top priority.
We’ve also seen a gradual effect on language, which we can detect after two to three months. Sometimes there are improvements in other behaviors too; I’ve seen mood-stabilizing effects. Many people with fragile X syndrome have issues with aggression, and it’s possible these could be moderated with metformin too. 

Individuals with fragile X syndrome (FXS) have both behavioral and medical comorbidities and the latter include obesity in approximately 30% and the Prader‐Willi Phenotype (PWP) characterized by severe hyperphagia and morbid obesity in less than 10%. Metformin is a drug used in individuals with type 2 diabetes, obesity or impaired glucose tolerance and it has a strong safety profile in children and adults. Recently published studies in the Drosophila model and the knock out mouse model of FXS treated with metformin demonstrate the rescue of multiple phenotypes of FXS.

Materials and Methods

We present 7 cases of individuals with FXS who have been treated with metformin clinically. One case with type 2 diabetes, 3 cases with the PWP, 2 adults with obesity and/or behavioral problems and, a young child with FXS. These individuals were clinically treated with metformin and monitored for behavioral changes with the Aberrant Behavior Checklist and metabolic changes with a fasting glucose and HgbA1c.

Results

We found consistent improvements in irritability, social responsiveness, hyperactivity, and social avoidance, in addition to comments from the family regarding improvements in language and conversational skills. No significant side‐effects were noted and most patients with obesity lost weight.

Conclusion

We recommend a controlled trial of metformin in those with FXS. Metformin appears to be an effective treatment of obesity including those with the PWP in FXS. Our study suggests that metformin may also be a targeted treatment for improving behavior and language in children and adults with FXS.

Recruiting: Clinical Trial of Metformin for Fragile X Syndrome


While a growing number of families are trying metformin and reporting mixed results, metformin has not yet been systematically studied in patients with Fragile X syndrome. This open-label trial is designed to better understand the safety and efficacy of this medicine on behavior and cognition, and to find the best dosages for children and adults.

20 children and adults with Fragile X syndrome will take metformin 250mg twice a day for the first week, followed by metformin 500mg twice a day for the next 8 weeks.
The study will measure changes in the total score on the Aberrant Behavior Checklist-Community (ABC-C) after 9 weeks of metformin treatment. The ABC-C is a 58-item behavior scale which is filled out by a caregiver. In addition, Transcranial Magnetic Stimulation (TMS) will be used to look for changes in cortical excitability and Electroencephalography (EEG) will assess levels of synaptic plasticity.
Participants in this study must be Canadian residents and be able to travel to the University of Sherbrooke in Quebec, Canada, for several visits. If you are interested in metformin but this trial is not convenient, there are two alternatives. FRAXA is funding a new trial of metformin in New Jersey, and Dr. Randi Hagerman is currently recruiting for metformin trial at the University of California at Davis MIND Institute.



Metformin has emerged as a candidate drug for the targeted treatment of FXS based on animal studies showing rescue of multiple phenotypes in the FXS model. Metformin may contribute to normalizing signalling pathways in FXS in the central nervous system, which may include activities of mTOR and PI3K, both of which have shown to be pathogenically overactive in FXS. In addition, metformin inhibits phosphodiesterase, which would lead to correction of cAMP levels, and MMP9 production, which is also elevated in FXS. Looking at the potential signalling pathways, metformin appears to be a good candidate for targeting several of the intracellular functions in neurons disrupted in FXS and, therefore, has potential to rescue several types of symptoms in individuals with FXS. The researchers have utilized metformin in the clinical treatment of over 20 individuals with FXS between the ages of 4 and 58 years and have found the medication to be well tolerated and to provide benefits not only in lowering weight gain and normalizing appetite but also in language and behavior. In this controlled trial, the researchers hope to further assess metformin's safety and benefits in the areas of language and cognition, eating and weight loss, and overall behavior.


mTOR and P13K

Hagerman highlights Metformin’s effects on mTOR and P13K pathways.

This is a highly complex subject and the graphic below from an early post shows how interconnected everything is.  If mTOR is not working correctly you can expect many things not to work as nature intended.

Numerous things can cause an imbalance in mTOR and so there are numerous ways to re-balance it.

Not surprisingly much of this pathway plays a role in many types of cancer.

Hagerman herself is taking Metformin to reduce her chances of developing cancer. I think that is a good choice, particularly if you are overweight.  My anticancer choice, not being overweight, is Atorvastatin which targets inhibition of PI3K signalling through Akt and increases PTEN.

Hagerman is 70 years old and I think many cancers actual initiate years before they are large enough to get noticed and to be effective any preventative therapy needs to be started before that initiation has occurred. Hopefully she started her Metformin long ago. 

Given that 50% of people are likely to develop one cancer or another, I am with Dr Hagerman on the value of prevention, rather than treatment/cure.







The Wrong Statin for Fragile-X?

In the first article highlighted in this post, there is a case history of a man with FX being treated by a Statin, it looks to me that he has the wrong prescription (Simvastatin). Perhaps Dr Hagerman should read this old post from this blog:-


Choose your Statin with Care in FXS, NF1 and idiopathic Autism







   Simvastatin does not reduce ERK1/2 or mTORC1 activation in the Fmr1-/y hippocampus.
So  ? = Does NOT inhibit

The key is to reduce Ras. In the above graphic it questions does Simvastatin inhibit RAS and Rheb.
                                                                                                     

For anyone really interested, the following graphic from a previous post shows the fragile X mental retardation protein, FMRP.  Lack of FMRP goes on increase neuroligins (NLFNS) this then creates an excitatory/inhibitory imbalance which cause mental retardation and features of autism.





This all suggests that the 25 year-old young man with Fragile X treated at UC Davis (case study above) should switch from Simvastatin to Lovastatin.




Metformin and Autophagy

I also think Dr Hagerman is less likely to get dementia now that she is talking metformin.  If she takes vigorous exercise at least once a week, I think that is also going to keep her grey cells ticking over nicely. Like Dr Ben Ari, Hr Hagerman is working way past normal retirement.  If you love your job, then why not?  As with many things, in the case of neurons, “use them or lose them”.

Autophagy in Dementias


Dementias are a varied group of disorders typically associated with memory loss, impaired judgment and/or language and by symptoms affecting other cognitive and social abilities to a degree that interferes with daily functioning. Alzheimer’s disease (AD) is the most common cause of a progressive dementia, followed by dementia with Lewy bodies (DLB), frontotemporal dementia (FTD), vascular dementia (VaD) and HIV associated neurocognitive disorders (HAND).
The pathogenesis of this group of disorders has been linked to the abnormal accumulation of proteins in the brains of affected individuals, which in turn has been related to deficits in protein clearance. Autophagy is a key cellular protein clearance pathway with proteolytic cleavage and degradation via the ubiquitin-proteasome pathway representing another important clearance mechanism. Alterations in the levels of autophagy and the proteins associated with the autophagocytic pathway have been reported in various types of dementias. This review will examine recent literature across these disorders and highlight a common theme of altered autophagy across the spectrum of the dementias.

Below is an excellent graphic from a paper highlighted by Ling. Note metformin, above AMPK.


Autophagy Activator Drugs: A New Opportunity in Neuroprotection from Misfolded Protein Toxicity









I would highlight the presence of IP3R, the calcium channel proposed by Gargus as being a nexus in autism, for where multiple types of autism meet up, to do damage.

Verapamil, in Monty’s Polypill, increases autophagy independently of mTOR in a complicated mechanism  involving IP3R and likley calpain.  It is proposed as a therapy for Huntington’s Disease via this mechanism. At the lower right of the chart below we see calpain, a group of calcium dependent enzymes, not well understood.  ROS can activate calpains via L-type calcium channels.





I would not worry about the details.  The take home point is that if you have autism, dementia or many other neurological conditions, you might well benefit from increasing autophagy.  There are very many ways to do this.      
                                                           
Conclusion

Fortunately, I am not a doctor.  I do recall when my doctor father was out visiting his sick patients at their homes, he did have not only his medical bag, but also some useful gadgets always kept in his car, that might come in handy.

The autism equivalent is the personalized Polypill therapy for daily use and the autism toolbox to delve into to treat flare-ups in autism as and when they arise.

I do think some people should have metformin in their daily Polypill therapy.

I think we can safely call Fragile-X a type of autism, so we already know it works for at least some autism.  Metformin is a very safe old drug, with minimal side effects and it is cheap.  It ticks all the boxes for a potential autism therapy.  Will it work for your case?  I can tell you with certainty that it does not work for everyone.

Metformin has been trialled to treat people with obesity and autism, since it can reduce appetite.

Metformin forTreatment of Overweight Induced by Atypical Antipsychotic Medication in YoungPeople With Autism Spectrum Disorder: A Randomized Clinical Trial.


INTERVENTIONS:

Metformin or matching placebo titrated up to 500 mg twice daily for children aged 6 to 9 years and 850 mg twice daily for those 10 to 17 years.

MAIN OUTCOMES AND MEASURES:

The primary outcome measure was change in body mass index (BMI) z score during 16 weeks of treatment. Secondary outcomes included changes in additional body composition and metabolic variables. Safety, tolerability, and efficacy analyses all used a modified intent-to-treat sample comprising all participants who received at least 1 dose of medication.

RESULTS:

Of the 61 randomized participants, 60 participants initiated treatment (45 [75%] male; mean [SD] age, 12.8 [2.7] years). Metformin reduced BMI z scores from baseline to week 16 significantly more than placebo (difference in 16-week change scores vs placebo, -0.10 [95% CI, -0.16 to -0.04]; P = .003). Statistically significant improvements were also noted in secondary body composition measures (raw BMI, -0.95 [95% CI, -1.46 to -0.45] and raw weight, -2.73 [95% CI, -4.04 to -1.43]) but not in metabolic variables. Overall, metformin was well tolerated. Five participants in the metformin group discontinued treatment owing to adverse events (agitation, 4; sedation, 1). Participants receiving metformin vs placebo experienced gastrointestinal adverse events during a significantly higher percentage of treatment days (25.1% vs 6.8%; P = .005).

CONCLUSIONS AND RELEVANCE:

Metformin may be effective in decreasing weight gain associated with atypical antipsychotic use and is well tolerated by children and adolescents with ASD.

My guess is that a minority will be responders, the benefit will manifest itself in different ways and so it will be a useful part of polytherapy for some people, but it will not be a silver bullet.  Other than via an IQ test, I think the benefit will be hard to measure, even when it is very evident. 

In the end there will be a clever way to predict who will respond to which therapy.  Today’s post actually replaces one that will look into genetic testing and DEGs (differentially expressed genes). Most likely testing for DEGs will be the best predictor of what drugs work for whom.

Intelligent, cautious trial and error using safe drugs is an alternative strategy.  It is available today; it is cheap and it does work.

I have not tried Metformin yet, in recent years I have had most success with my own ideas. I have some of Dr Frye's calcium folinate sitting at home waiting for a trial.  Both Metformin and calcium folinate should be trialled.  The other obvious thing to trial is that Japanese PDE4 inhibitor Ibudilast (Ketas).  Thanks to Rene we now know you can acquire this is via any international pharmacy in Germany, with a prescription. It also reappeared on the website of a Japanese online pharmacy. The Western PDE4 inhibitors, like Daxas/Roflumilast are not selective enough and so are emetic (they make you want to vomit). Low dose Roflumilast has been patented as a cognitive enhancer, but you may need to have a bucket with you at all times.




     






Wednesday, 23 October 2019

GABAa receptor trafficking, Migraine, Pain, Light Sensitivity, Autophagy, Jacobsen Syndrome, Angelman Syndrome, GABARAP, TRPV1, PX-RICS, CaMKII and CGRP ... Oh and the "fever effect"



The mechanism controlling transporting just the “right” number of GABAA receptors


Today’s post is not for the faint-hearted.  It is another one that could just keep on rolling.  Ling will like it.

It again shows that GABAA receptors are at the centre of much autism, whether single gene or idiopathic. Today we highlight what can go wrong as these receptors are “transported”.

Today’s post also draws on several quite recent papers. It seeks to tie together some previous things mentioned in this blog like the symptoms of pain, particularly felt in the head, sensory sensitivity with dysfunction processes like autophagy and linking it all back to the GABAA receptor.  There is even a link at the end to the "fever effect", which occurs when a high temperature in some people causes a marked improvement in their autism symptoms.

We will come across some expensive drugs like Erenumab, the medical food PEA (Palmitoylethanolamide) and indeed Natasa’s favourite, CBD (Cannabidiol) and a newcomer CBDV (Cannabidivarin).   
We come across a protein called GABARAP (GABAA receptor associated protein) for the first time in this blog.  There is a vast amount in this blog about the GABAA receptor, how and why to modulate it. 

CaMKII makes an appearance, this is a protein kinase that is miss-regulated in much neurological disease. It changes the effect of many other proteins, acting just like a switch, by chemically adding phosphate groups to them. We have previously seen how important the protein kinases PKA, PKB and PKC are to autism.  Today add CaMKII to the list.

We come across another distinctive “face” of autism, this time it is Jacobsen syndrome, which I think is easily spotted by the trained eye, or some facial recognition software.  Jacobsen syndrome is a rare chromosomal disorder resulting from deletion of genes from chromosome 11 that includes band 11q24. This may include the gene that encodes the protein PX-RICS and, if so, it will lead to “autism”. Loss of that gene should be treatable with a GABA agonist.     

We also come back to that happy puppet syndrome (Angelman syndrome) which usually involves loss of the gene UBE3A, from chromosome 15. What I found interesting was that both Jacobsen syndrome and Angelman syndrome should share impaired GABAA receptor trafficking as a feature. They each have a different impediment that should reduce the number of functioning GABAA receptors. In the case of Angelman the impediment is CaMKII inhibition, in Jacobsen it is lack of the protein PX-RICS. Angelman syndrome may well respond to the same therapy as Jacobsen syndrome – a GABA agonist, of just a PAM (positive allosteric modulator, to “turn up the volume”).

Back to GABARAP

GABARAP has multiple functions:

1.     Transport of freshly minted GABAA receptors

In order for newly minted GABAA receptors to get to their final destination it requires four “helpers”: GABARAP, PX-RICS, 14-3-3 and Dynactin.  In addition, you need a dose of CaMKII. If you lack any one of these four, you will end up with reduced expression of GABAA receptors. If CaMKII is overactivated you get too many GABAA receptors.

In Jacobsen Syndrome there is reduced GABAA receptor trafficking/transport, leading to reduced surface expression. (in effect not enough functioning GABAA receptors in situ).  In some people with this syndrome the part of their DNA which encodes PX-RICS is missing.  This lack of PX-RICS produces autism.  The autism-like behavioural abnormalities in PX-RICS-deficient mice are ameliorated by enhancing inhibitory synaptic transmission with a GABAAR agonist.

2.     GABARAP modulates TRPV1 expression

GABARAP also does something totally different, it modulates TRPV1 ion channels, that we have previously touched on in this blog.  This then triggers a cascade of effects relating to pain, neuralgia, migraine headaches, microglial activation, epilepsy and indeed longevity.

The simple function of TRPV1 is detection and regulation of body temperature. In addition, TRPV1 provides a sensation of scalding heat and pain. TRPV1 is also known as the capsaicin receptor.  Capsaicin is the active component of chilli peppers.
TRPV1 not only plays a role in pain, but is suggested to play a role in migraine. In migraine TRPV1 plays a role along with calcitonin gene-related peptide receptor (CGRPR). TRPV1 determines how much of the CGRPR protein is produced. CGRPR affects your metabolism broadly and as such plays a key role in longevity.  Ablation of select pain sensory receptors (TRPV1) or the inhibition of CGRP are associated with increased metabolic health and longevity.
Erenumab/Aimovig is a medication which targets CGRPR for the prevention of migraine. It was the first of the group of CGRPR antagonists to be FDA approved in 2018. It is a form of monoclonal antibody therapy in which antibodies are used to block the receptors for the protein CGRP, thought to play a major role in starting migraines.
Recent evidence suggests that TRPV1 may contribute to the onset and progression of some forms of epilepsy;  Cannabidivarin  (CBDV) and cannabidiol (CBD), activate and desensitize TRPV1.
TRPV1 also plays a crucial role in the activation of microglia. As the researchers put it “TRPV1 channels are critical brain inflammation detectorsmicroglia shifted toward an anti-inflammatory phenotype when TRPV1 is lacking.

So, if we jump a few steps forward we can see that desensitizing TRPV1 might be helpful for people with: -

·        Some epilepsy
·        Some neuralgia
·        Perhaps some with chronic migraine
·        People with activated microglia, which is most autism

We also can see that a dysfunction in GABARAP may itself contribute to worsening the above conditions via its effect on TRPV1.


Epilepsy is the most common neurological disorder, with over 50 million people worldwide affected. Recent evidence suggests that the transient receptor potential cation channel subfamily member 1 (TRPV1) may contribute to the onset and progression of some forms of epilepsy. V Since the two nonpsychotropic cannabinoids cannabidivarin (CBDV) and cannabidiol (CBD) exert anticonvulsant activity in vivo and produce TRPV1-mediated intracellular calcium elevation in vitro, we evaluated the effects of these two compounds on TRPV1 channel activation and desensitization and in an in vitro model of epileptiform activity. Patch clamp analysis in transfected HEK293 cells demonstrated that CBD and CBDV dose-dependently activate and rapidly desensitize TRPV1, as well as TRP channels of subfamily V type 2 (TRPV2) and subfamily A type 1 (TRPA1). TRPV1 and TRPV2 transcripts were shown to be expressed in rat hippocampal tissue. When tested on epileptiform neuronal spike activity in hippocampal brain slices exposed to a Mg2+-free solution using multielectrode arrays (MEAs), CBDV reduced both epileptiform burst amplitude and duration. The prototypical TRPV1 agonist, capsaicin, produced similar, although not identical effects. Capsaicin, but not CBDV, effects on burst amplitude were reversed by IRTX, a selective TRPV1 antagonist. These data suggest that CBDV antiepileptiform effects in the Mg2+-free model are not uniquely mediated via activation of TRPV1. However, TRPV1 was strongly phosphorylated (and hence likely sensitized) in Mg2+-free solution-treated hippocampal tissue, and both capsaicin and CBDV caused TRPV1 dephosphorylation, consistent with TRPV1 desensitization. We propose that CBDV effects on TRP channels should be studied further in different in vitro and in vivo models of epilepsy.


TRPV1 channels are critical brain inflammation detectors and neuropathic pain biomarkers in mice

The capsaicin receptor TRPV1 has been widely characterized in the sensory system as a key component of pain and inflammation. A large amount of evidence shows that TRPV1 is also functional in the brain although its role is still debated. Here we report that TRPV1 is highly expressed in microglial cells rather than neurons of the anterior cingulate cortex and other brain areas. We found that stimulation of microglial TRPV1 controls cortical microglia activation per se and indirectly enhances glutamatergic transmission in neurons by promoting extracellular microglial microvesicles shedding. Conversely, in the cortex of mice suffering from neuropathic pain, TRPV1 is also present in neurons affecting their intrinsic electrical properties and synaptic strength. Altogether, these findings identify brain TRPV1 as potential detector of harmful stimuli and a key player of microglia to neuron communication.

TRPV1 controls cortical microglia activation

In the healthy mature brain, microglial cells play a role in immune surveillance and ensure the maintenance of brain homeostasis. Upon injuries these cells shift to an activated state characterized by drastic changes in the cellular shape, functional behavior and by the release of different proinflammatory and immunoregulatory factors58,59. Conforming to the capsaicin-mediated induction of microglial chemotaxis29, we investigated whether TRPV1 stimulation regulates the morphology of microglial cells…. Thus, stimulation of TRPV1 induced a pro-inflammatory phenotype of microglia from WTs. Conversely, microglia shifted toward an anti-inflammatory phenotype when TRPV1 is lacking.


Angelman syndrome

Angelman syndrome (Happy puppet syndrome) is a genetic disorder that mainly affects the nervous system. Symptoms include a small head and a specific facial appearance, severe intellectual disability, developmental disability, speaking problems, balance and movement problems, seizures, and sleep problems. Children usually have a happy personality and have a particular interest in water. The symptoms generally become noticeable by one year of age.  Angelman syndrome is typically due to a new mutation rather than one inherited from a person's parents. Angelman syndrome is due to a lack of function of part of chromosome 15 inherited from a person's mother. Most of the time, it is due to a deletion or mutation of the UBE3A gene.

CaMKII inhibition underlies Angelman Syndrome



CaMKII
CaMKII is a serine/threonine-specific protein kinase that is regulated by the Ca2+/calmodulin complex. CaMKII is involved in many signaling cascades and is thought to be an important mediator of learning and memory. CaMKII is also necessary for Ca2+ homeostasis and reuptake in cardiomyocytes, chloride transport in epithelia, positive T-cell selection, and CD8 T-cell activation.
Misregulation of CaMKII is linked to Alzheimer’s disease, Angelman syndrome, and heart arrhythmia.

Recent evidence for CaMKII dysregulation in psychiatric diseases is reviewed.
Changes in postsynaptic structure and function appear to be central to multiple diseases.
Altered regulation of the CaMKIIα gene promoter may be a common mechanism among diseases.
CaMKII dysregulation in diverse brain regions may account for myriad disorders.
Although it has been known for decades that hippocampal calcium/calmodulin (CaM)-dependent protein kinase II (CaMKII) plays an essential role in learning and memory consolidation, the roles of CaMKII in other brain regions are only recently being explored in depth. A series of recent studies suggest that CaMKII dysfunction throughout the brain may underlie myriad neuropsychiatric disorders, including drug addiction, schizophrenia, depression, epilepsy, and multiple neurodevelopmental disorders, perhaps through maladaptations in glutamate signaling and neuroplasticity. I review here the structure, function, subcellular localization, and expression patterns of CaMKII isoforms, as well as recent advances demonstrating that disturbances in these properties may contribute to psychiatric disorders.

A Novel Human CAMK2A Mutation Disrupts Dendritic Morphology and Synaptic Transmission, and Causes ASD-Related Behaviors


Characterizing the functional impact of novel mutations linked to autism spectrum disorder (ASD) provides a deeper mechanistic understanding of the underlying pathophysiological mechanisms. Here we show that a de novo Glu183 to Val (E183V) mutation in the CaMKIIα catalytic domain, identified in a proband diagnosed with ASD, decreases both CaMKIIα substrate phosphorylation and regulatory autophosphorylation, and that the mutated kinase acts in a dominant-negative manner to reduce CaMKIIα-WT autophosphorylation. The E183V mutation also reduces CaMKIIα binding to established ASD-linked proteins, such as Shank3 and subunits of l-type calcium channels and NMDA receptors, and increases CaMKIIα turnover in intact cells. In cultured neurons, the E183V mutation reduces CaMKIIα targeting to dendritic spines. Moreover, neuronal expression of CaMKIIα-E183V increases dendritic arborization and decreases both dendritic spine density and excitatory synaptic transmission. Mice with a knock-in CaMKIIα-E183V mutation have lower total forebrain CaMKIIα levels, with reduced targeting to synaptic subcellular fractions. The CaMKIIα-E183V mice also display aberrant behavioral phenotypes, including hyperactivity, social interaction deficits, and increased repetitive behaviors. Together, these data suggest that CaMKIIα plays a previously unappreciated role in ASD-related synaptic and behavioral phenotypes.
SIGNIFICANCE STATEMENT Many autism spectrum disorder (ASD)-linked mutations disrupt the function of synaptic proteins, but no single gene accounts for >1% of total ASD cases. The molecular networks and mechanisms that couple the primary deficits caused by these individual mutations to core behavioral symptoms of ASD remain poorly understood. Here, we provide the first characterization of a mutation in the gene encoding CaMKIIα linked to a specific neuropsychiatric disorder. Our findings demonstrate that this ASD-linked de novo CAMK2A mutation disrupts multiple CaMKII functions, induces synaptic deficits, and causes ASD-related behavioral alterations, providing novel insights into the synaptic mechanisms contributing to ASD.

Jacobsen Sydrome

The signs and symptoms of Jacobsen syndrome can vary. Most affected people have delayed development of motor skills and speech; cognitive impairment; and learning difficulties. Behavioral features have been reported and may include compulsive behavior; a short attention span; and distractibility. Many people with the condition are diagnosed with attention deficit-hyperactivity disorder (ADHD). The vast majority of people with Jacobsen syndrome also have a bleeding disorder called Paris-Trousseau syndrome, which causes abnormal bleeding and easy bruising. 

People with Jacobsen syndrome typically have distinctive facial features, which include small and low-set ears; wide-set eyes (hypertelorism) with droopy eyelids (ptosis); skin folds covering the inner corner of the eyes; a broad nasal bridge; down-turned corners of the mouth; a thin upper lip; and a small lower jaw (micrognathia). Affected people often have a large head (macrocephaly) and a skull abnormality called trigonocephaly, giving the forehead a pointed appearance.

The Autism-Related Protein PX-RICS Mediates GABAergic Synaptic Plasticity in Hippocampal Neurons and Emotional Learning in Mice


GABAergic dysfunction underlies many neurodevelopmental and psychiatric disorders. GABAergic synapses exhibit several forms of plasticity at both pre- and postsynaptic levels. NMDA receptor (NMDAR)–dependent inhibitory long-term potentiation (iLTP) at GABAergic postsynapses requires an increase in surface GABAARs through promoted exocytosis; however, the regulatory mechanisms and the neuropathological significance remain unclear. Here we report that the autism-related protein PX-RICS is involved in GABAAR transport driven during NMDAR–dependent GABAergic iLTP. Chemically induced iLTP elicited a rapid increase in surface GABAARs in wild-type mouse hippocampal neurons, but not in PX-RICS/RICS–deficient neurons. This increase in surface GABAARs required the PX-RICS/GABARAP/14–3-3 complex, as revealed by gene knockdown and rescue studies. iLTP induced CaMKII–dependent phosphorylation of PX-RICS to promote PX-RICS–14-3-3 assembly. Notably, PX-RICS/RICS–deficient mice showed impaired amygdala–dependent fear learning, which was ameliorated by potentiating GABAergic activity with clonazepam. Our results suggest that PX-RICS–mediated GABAAR trafficking is a key target for GABAergic plasticity and its dysfunction leads to atypical emotional processing underlying autism.

There is a growing consensus that autism arises from the atypical regulation of the excitation/inhibition balance within specific neural microcircuitry. In terms of neural inhibition, autism is closely related to dysfunctional inhibitory signaling mediated by the γ-aminobutyric acid (GABA) type A receptors (GABAARs). Impaired presynaptic release of GABA and postsynaptic trafficking of GABAARs lead to autistic-like social behavior in mouse models of autism. There is a significant reduction in the number of GABAARs and GABAergic activity in certain brain areas of autistic individuals. Genetic association studies have revealed that several GABAAR subunits are linked to an increased risk for autism. GABAAR–mediated signaling is thus essential for the proper regulation of the excitation/inhibition balance associated with socio-emotional cognition.

PX-RICS, GABARAP and 14-3-3ζ/θ are localized in the specific dendritic compartments that are immunopositive for organelle markers for the endoplasmic reticulum (ER), ER exit sites and the trans-Golgi network. This structure, termed the dendritic satellite secretory pathway, is comprised of the dendritic ER and the Golgi outposts and is involved in the local synthesis, processing and transport of membrane-integral or secretory proteins in dendrites. The rapid increase in surface-expressed GABAARs after NMDA stimulation could be explained by the localization of the PX-RICS–dependent trafficking machinery in the dendritic secretory compartments.
Several lines of evidence suggest that the dysregulation of GABA signaling underlies atypical social behavior in autism However, there has been no report describing deficits in GABAergic plasticity that contribute to autistic features. The present study has shown that PX-RICS is essential for GABAergic iLTP and that loss of the PX-RICS function in mice leads to impaired cued fear learning. Cued fear learning is closely associated with GABAAR–mediated activity and plasticity in the amygdala and is inversely correlated with the severity of autistic symptoms. Considering all of these findings, we thus reason that PX-RICS–dependent GABAAR transport may play critical roles in emotional learning in the amygdala through the control of GABAergic synaptic plasticity and that the impairment of this transport mechanism may lead to improper socio-emotional processing, resulting in autistic-like atypical social behavior (Supplementary Fig. 7). Further elucidation of the functional link between GABAergic plasticity and socio-emotional learning could lead to a better understanding of autism pathogenesis and treatment. 
We have previously identified and characterized two splicing isoforms of GTPase-activating proteins specific for Cdc42 predominantly expressed in neurons of the cerebral cortex, amygdala and hippocampus: RICS (ARHGAP32 isoform 2) and PX-RICS (ARHGAP32 isoform 1) . RICS regulates NMDAR–mediated signaling at the postsynaptic density and axonal elongation at the growth cone. In contrast, PX-RICS forms an adaptor complex with GABARAP and 14-3-3ζ/θ to facilitate steady-state trafficking of the N-cadherin/β-catenin complex and GABAARs. PX-RICS is also responsible for autistic-like features observed in more than half of the patients with Jacobsen syndrome (JBS) [3]. Mice lacking PX-RICS/RICS show marked decreases in surface-expressed GABAARs and GABAAR–mediated inhibitory synaptic transmission, resulting in various autistic-like behaviors and autism-related comorbidities. Rare single-nucleotide variations in PX-RICS are also linked to non-syndromic autism, schizophrenia and alexithymia. These findings strongly suggest that dysfunction of PX-RICS–mediated GABAAR trafficking has severe effects on socio-emotional processing of the brain.
Our previous study described above showed that PX-RICS and other components of the GABAAR trafficking complex are required for constitutive transport of the receptor. In this study, we have focused on the role of PX-RICS in the activity–induced promotion of GABAAR trafficking during iLTP. Here we show that PX-RICS–mediated GABAAR trafficking is also involved in NMDAR activity–dependent trafficking of GABAARs and that PX-RICS is a key target of CaMKII for regulating GABAergic synaptic plasticity. Furthermore, we show that PX-RICS dysfunction in mice leads to impaired amygdala–dependent emotional learning, which manifests as autistic-like social behavior [3].




Supplementary Fig. 7. PX-RICS–mediated GABAAR trafficking underlies NMDAR–dependent GABAergic iLTP PX-RICS, GABARAP and 14-3-3s are assembled to form an adaptor complex that interconnects γ2-containing GABAARs (cargo) and dynein/dynactin (motor). Interaction
of PX-RICS with 14-3-3s depends on the phosphorylation activity of CaMKII, and this interaction is a critical regulatory point for GABAAR trafficking. When CaMKII activity is at a basal level, the PX-RICS–mediated trafficking complex has a role in steady-state transport of GABAARs to maintain the number of surface GABAARs as needed for proper synaptic inhibition.3 Neural activity that evokes moderate Ca2+ influx through NMDAR preferentially increases the activated form of CaMKII and elicits its translocation to inhibitory synapses, where it phosphorylates target proteins such as gephyrin and the GABAAR β3 subunit. Phosphorylated gephyrin and the GABAAR β3 subunit regulate the surface dynamics of GABAARs such as lateral diffusion and synaptic confinement. The present study has revealed that PXRICS
is a downstream CaMKII target associated with anterograde transport of
GABAARs. Enhanced PX-RICS phosphorylation increases the PX-RICS–14-3-3 complex and thereby drives de novo GABAAR surface expression, resulting in GABAergic iLTP. Dysfunction of this trafficking mechanism in the amygdala causes impaired GABAergic synaptic plasticity, which may contribute to deficits in socioemotional behavior as observed in PX-RICS/RICS–deficient mice and JBS patients with autism.


PX-RICS-deficient mice mimic autism spectrum disorder in Jacobsen syndrome through impaired GABAA receptor trafficking


Jacobsen syndrome (JBS) is a rare congenital disorder caused by a terminal deletion of the long arm of chromosome 11. A subset of patients exhibit social behavioural problems that meet the diagnostic criteria for autism spectrum disorder (ASD); however, the underlying molecular pathogenesis remains poorly understood. PX-RICS is located in the chromosomal region commonly deleted in JBS patients with autistic-like behaviour. Here we report that PX-RICS-deficient mice exhibit ASD-like social behaviours and ASD-related comorbidities. PX-RICS-deficient neurons show reduced surface γ-aminobutyric acid type A receptor (GABAAR) levels and impaired GABAAR-mediated synaptic transmission. PX-RICS, GABARAP and 14-3-3ζ/θ form an adaptor complex that interconnects GABAAR and dynein/dynactin, thereby facilitating GABAAR surface expression. ASD-like behavioural abnormalities in PX-RICS-deficient mice are ameliorated by enhancing inhibitory synaptic transmission with a GABAAR agonist. Our findings demonstrate a critical role of PX-RICS in cognition and suggest a causal link between PX-RICS deletion and ASD-like behaviour in JBS patients.


TRPV1

We now come back to TRPV1, which we saw is modulated by GABARAP.

GABAA receptor associated protein (GABARAP) modulates TRPV1 expression and channel function and desensitization


Transient receptor potential vanilloid (TRPV1) transduces noxious chemical and physical stimuli in high-threshold nociceptors. The pivotal role of TRPV1 in the physiopathology of pain transduction has thrust the identification and characterization of interacting partners that modulate its cellular function. Here, we report that TRPV1 associates with γ-amino butyric acid A-type (GABAA) receptor associated protein (GABARAP) in HEK293 cells and in neurons from dorsal root ganglia coexpressing both proteins. At variance with controls, GABARAP augmented TRPV1 expression in cotransfected cells and stimulated surface receptor clustering. Functionally, GABARAP expression attenuated voltage and capsaicin sensitivity of TRPV1 in the presence of extracellular calcium. Furthermore, the presence of the anchor protein GABARAP notably lengthened the kinetics of vanilloid-induced tachyphylaxia. Notably, the presence of GABARAP selectively increased the interaction of tubulin with the C-terminal domain of TRPV1. Disruption of tubulin cytoskeleton with nocodazole reduced capsaicin-evoked currents in cells expressing TRPV1 and GABARAP, without affecting the kinetics of vanilloid-induced desensitization. Taken together, these findings indicate that GABARAP is an important component of the TRPV1 signaling complex that contributes to increase the channel expression, to traffic and cluster it on the plasma membrane, and to modulate its functional activity at the level of channel gating and desensitization.

‘Entourage’ effectsof N‐palmitoylethanolamide and N‐oleoylethanolamide on vasorelaxation to anandamide occur through TRPV1 receptors



Age-Dependent Anti-seizure and Neuroprotective Effect of Cannabidivarin in Neonatal Rats


Neonatal seizures and seizures of infancy represent a significant cause of morbidity. 30–40% of infants and children with seizures will fail to achieve seizure remission with current anti-epileptic drug (AED) treatment. Moreover, pharmacotherapy during critical periods of brain development can adversely affect nervous system function. We, and others, have shown that early life exposure to AEDs including phenobarbital, phenytoin, and valproate are associated with induction of enhanced neuronal apoptosis during a confined period of postnatal development in rats. Thus, identification of new therapies for neonatal/infantile epilepsy syndromes that provide seizure control without neuronal toxicity is a high priority.
Current clinical trials report that modulation of the cannabinoid system with the phytocannabinoid cannabidiol exerts anti-seizure effects in children with epilepsy. While cannabidiol and the propyl analog cannabidivarin (CBDV) display anti-seizure efficacy in adult animal models of seizures/epilepsy, they remained unexplored in neonatal models. Therefore, we investigated the therapeutic potential of CBDV in multiple neonatal rodent seizure models. To evaluate the therapeutic potential of CBDV, we tested its anti-seizure efficacy in five models of neonatal seizures: pentylenetetrazole (PTZ), DMCM, hypoxia, kainate and NMDA-evoked spasms, each representing a different clinical seizure phenotype. We also evaluated the preclinical safety profile in the developing brain.
Postnatal day (P) 10 or P20 male, Sprague-Dawley rat pups were pretreated with CBDV or vehicle prior to chemically or hypoxia induced seizures. CBDV only displayed anticonvulsant effects in the P20 rat pups in the PTZ and DMCM models, with no effect on seizure severity or latency in the P10 animals. Therefore, we next measured the relative expression of known targets for CBDV (TRPV1, TRPA1) to determine a mechanism for which CBDV is anticonvulsant in P20, but not P10 animals. The P20 animals show increased expression of TRPV1 in key brain regions implicated in epileptogenic activity.
Together, these results indicate that modulation of the cannabinoid system in a receptor independent manner can provide seizure control in developing animals, but in an age specific manner. Further, during a developmentally sensitive neonatal period, drugs targeting the cannabinoid system do not induce neuronal apoptosis characteristic of many other AEDs. These results provide some of the first systemic, preclinical data evaluating CBDV in pediatric models of epilepsy.


Weight-based dosing of 10 mg/kg/day of CBDV for 12 weeks
Primary Outcome Measures  :
1.     Aberrant Behavior Checklist-Irritability Subscale (ABC-I) [ Time Frame: Change in ABC-I from Baseline to Week 12 (Change over 12 weeks) ]
Change in ABC-I from Baseline to Endpoint


  

Lack of Autophagy will reduce the number of GABAA receptors, by blocking GABARAP function

Regular readers will recall that one feature of autism and many other neurological diseases is a reduction in autophagy, which I likened to an intra-cellular garbage collection service. 

The very recent paper below shows that lack of autophagy blocks GABARAP from its job to transport freshly minted GABAA receptors.
If correct, this actually has very wide implications.



The disruption of MTOR-regulated macroautophagy/autophagy was previously shown to cause autistic-like abnormalities; however, the underlying molecular defects remained largely unresolved. In a recent study, we demonstrated that autophagy deficiency induced by conditional Atg7 deletion in either forebrain GABAergic inhibitory or excitatory neurons leads to a similar set of autistic-like behavioral abnormalities even when induced following the peak period of synaptic pruning during postnatal neurodevelopment. Our proteomic analysis and molecular dissection further revealed a mechanism in which the GABAA receptor trafficking function of GABARAP (gamma-aminobutyric acid receptor associated protein) family proteins was compromised as they became sequestered by SQSTM1/p62-positive aggregates formed due to autophagy deficiency. Our discovery of autophagy as a link between MTOR and GABA signaling may have implications not limited to neurodevelopmental and neuropsychiatric disorders, but could potentially be involved in other human pathologies such as cancer and diabetes in which both pathways are implicated.


Conclusion

You may have skipped to the conclusion to avoid all the science.

The conclusion is simple, you need to keep your GABAA receptors in tip top form if you want to avoid the symptoms of autism.

o   You need the right number of them
o   You need the right balance among the five constituent subunits
o   You need the correct level of chloride inside neurons so the receptors are not “working backwards”

All of the genes that encode proteins involved in the above are individually “autism genes”, because any one of them can disrupt the process.

Whether it is Dravet syndrome (GABAA receptor α2 subunit), Angelman syndrome, Jacobsen syndrome, Down syndrome or numerous other autism syndromes, not to mention idiopathic autism, check the above 3 bullet points.

Tune up/down your GABAA receptors!

Desensitizing TRPV1 looks interesting and not just for epilepsy.  TRPV1 appears to be essential for microglia in the in brain to be activated.  We know that in autism microglia in the brain are permanently activated, as if there was a threat.

I do think there is cross-talk (feedback loops etc) going on here, for example you can treat the severe epilepsy in Dravet syndrome by any of the following:-

·        KBr, to lower intracellular chloride
·        Low dose clonazepam to affect α subunits of GABAA receptors
·        CBD or CBDV to modify TRPV1


Note that Dravet syndrome is caused by a mutation in the gene that encodes the sodium ion channel Nav1.1, the dysfunction of GABAA receptors is a secondary effect. Also of interest is that the seizures that occur in Dravet syndrome are often triggered by hot temperatures or fever, so you can see how TRPV1 is indeed likely involved.  More generally in idiopathic autism, we have the "fever effect" when high temperatures trigger a reduction in autistic behaviors, making it the opposite of Dravet syndrome. 

On the one hand the biology behind the various problems may look horribly complicated and interwoven, the solutions appear to be much simpler and you have multiple options.

I await the results of the autism clinical trial of CBDV (Cannabidivarin) with interest.

Just impaired autophagy may lead to a reduction in GABAA receptors and the appearance of autistic features in an otherwise “normal” brain. This reminds us again of why autism is not a medical diagnosis, it is just a vague/subjective observation, which, in severe cases, should then trigger a thorough medical investigation.