Is dysregulated IP3R calcium signaling a nexus where genes altered in ASD converge to exert their deleterious effect?

Place de l'Étoile in Paris and the avenues radiating from it.  The Arc de Triomphe in the centre would be the IP3 receptor

There are a small number of researchers in the field of autism who really do seem to know what they are talking about;  one of those is Jay Gargus, from University of California at Irvine.  He is one of the few well versed on ion channel dysfunctions (channelopathies).  Today we look at his recent paper relating to the IP3R calcium channel in something called the endoplasmic reticulum (ER).

Gargus’ recent findings relate to calcium signaling, which we have seen previously in this blog to be dysfunctional in autism.  Blocking one type of calcium channel, with Verapamil, has had a remarkable effect in the children of some of those reading this blog; this has included resolving aggressive behavior, resolving GI problems and, most recently, greatly reducing seizures.  An interesting side effect of this drug is that it protects older people from Type 2 diabetes.

We will also encounter yet another kind of stress, ER stress (endoplasmic reticulum stress), which plays a role in many disorders including Type 2 diabetes and is suggested by some Japanese researchers to play a role in autism.  Interestingly some of my pet autism interventions are known to affect ER stress.

As usual in this blog, I will skip some of the complexities, but we do need to know some new words.  The explanation is mainly courtesy of the remarkable Wikipedia.

Organelle

In cell biology, an organelle is a specialized subunit within a cell that has a specific function.  Individual organelles are usually separately enclosed within their own lipid bilayers.  These lipid bilayers are also extremely important and need to be perfectly intact.  It does appear that these lipid bilayers are a little different in autism.

Components of a typical animal cell:

1.     Nucleolus
2.     Nucleus
3.     Ribosome (little dots)
4.    Vesicle
5.    Rough endoplasmic reticulum
6.    Golgi apparatus (or "Golgi body")
7.    Cytoskeleton
8.   Smooth endoplasmic reticulum
9.   Mitochondrion
10.   Vacuole
11.   Cytosol (fluid that contains organelles)
12.    Lysosome
13.    Centrosome
14.    Cell membrane

Endoplasmic Reticulum (ER) and ER Stress

The endoplasmic reticulum (ER) is the cellular organelle in which protein folding, calcium homeostasis, and lipid biosynthesis occur. Stimuli such as oxidative stress, ischemic insult, disturbances in calcium homeostasis, and enhanced expression of normal and/or folding-defective proteins lead to the accumulation of unfolded proteins, a condition referred to as ER stress.

Inositol trisphosphate receptor (InsP3R) or IP3R

IP3R is a Ca²⁺ channel activated by inositol trisphosphate (InsP3). InsP3R is very diverse among organisms, and is necessary for the control of cellular and physiological processes including cell division, cell proliferation, apoptosis, fertilization, development, behavior, learning and memory. Inositol triphosphate receptor represents a dominant second messenger leading to the release of Ca²⁺ from intracellular store sites.

It has a broad tissue distribution but is especially abundant in the cerebellum. Most of the InsP3Rs are found in the cell integrated into the endoplasmic reticulum.

Genes and autism

It is a widely held view that autism is essentially a genetic condition with some environmental triggers.

What is strange is that many hundreds, and later I suspect thousands, of genes are known to be implicated.  Do these lead to thousands of unique dysfunctions that ultimately manifest themselves as what we, rather clumsily, describe as “autism”?  This appears to be unlikely, more likely is that a much smaller number of downstream dysfunctions are involved.  This is behind what is suggested later by Gargus.

What I have always found odd is that siblings with idiopathic autism do NOT generally share the same genetic variations.  Most autism is called idiopathic, which means of unknown cause.  This is why I have not done any genetic testing on my son.

If siblings have Fragile X, then of course they do have the same genetic defect; the brother will likely be much more severely affected than the sister.

It occurs to me that unless the idiopathic autistic siblings live under some high voltage power cables, next to a TV transmitter or a chemical factory, the genetic testing must be missing something.  We have seen that sequencing the exome, the current “ultimate genetic test”, in fact only looks at 5% of genome.  We have also seen that in the remaining 95% are the so called enhancers and silencers of the genes in the exome.  We have also seen that overexpression of a perfect gene (as in Down syndrome) can do as much damage as a faulty gene.

My advice is to look in the remaining 95% of the genome.

Gargus, IP3R and Autism

Having completed the introduction now we can move on to the Gargus paper.

He is suggesting that a dysfunction at a specific calcium channel in the ER may be the common dysfunction triggered by “autism genes”.

So far he has only tested his idea on some single gene autisms, fragile X and tuberous sclerosis.

 

Shared functional defect in IP₃R-mediated calcium signaling in diverse monogenic autism syndromes

Autism spectrum disorder (ASD) affects 2% of children, and is characterized by impaired social and communication skills together with repetitive, stereotypic behavior. The pathophysiology of ASD is complex due to genetic and environmental heterogeneity, complicating the development of therapies and making diagnosis challenging. Growing genetic evidence supports a role of disrupted Ca²⁺ signaling in ASD. Here, we report that patient-derived fibroblasts from three monogenic models of ASD—fragile X and tuberous sclerosis TSC1 and TSC2 syndromes—display depressed Ca²⁺ release through inositol trisphosphate receptors (IP₃Rs). This was apparent in Ca²⁺ signals evoked by G protein-coupled receptors and by photoreleased IP₃ at the levels of both global and local elementary Ca²⁺ events, suggesting fundamental defects in IP₃R channel activity in ASD. Given the ubiquitous involvement of IP₃R-mediated Ca²⁺ signaling in neuronal excitability, synaptic plasticity, gene expression and neurodevelopment, we propose dysregulated IP₃R signaling as a nexus where genes altered in ASD converge to exert their deleterious effect. These findings highlight potential pharmaceutical targets, and identify Ca²⁺ screening in skin fibroblasts as a promising technique for early detection of individuals susceptible to ASD.

This part I found interesting:-

Because of the ubiquitous nature of IP3R signaling and its diverse roles in almost all cells of the body, deficits in IP3-mediated Ca2+ signaling may not be limited to neurological correlates of ASD, but may also explain other characteristic ASD-associated heterogeneous symptoms, such as those of the gastrointestinal tract and immune system.  Furthermore, since the ER serves as a sensor of a host of environmental stressors, this same mechanism may contribute to the known environmental component

to the ASD phenotype, and holds the potential to reveal relevant stressors.

Is it a coincidence that the Verapamil therapy I propose also benefits autism symptoms linked to the gastrointestinal tract and immune system (mast cells/allergy) and also now seizures (hyper excitability)?  I think not,

Here is the rather easier to read press release from the University:-

UCI researchers find biomarker for autism that may aid diagnostics

Study also points to potential new drug discovery advances

Irvine, Calif., Sept. 22, 2015 — By identifying a key signaling defect within a specific membrane structure in all cells, University of California, Irvine researchers believe, they have found both a possible reliable biomarker for diagnosing certain forms of autism and a potential therapeutic target.

Dr. J. Jay Gargus, Ian Parker and colleagues at the UCI Center for Autism Research & Translation examined skin biopsies of patients with three very different genetic types of the disorder (fragile X syndrome and tuberous sclerosis 1 and 2). They discovered that a cellular calcium signaling process involving the inositol trisphosphate receptor was very much altered.

This IP3R functional defect was located in the endoplasmic reticulum, which is among the specialized membrane compartments in cells called organelles, and may underpin cognitive impairments – and possibly digestive and immune problems – associated with autism.

“We believe this finding will be another arrow in the quiver for early and accurate diagnoses of autism spectrum disorders,” said Gargus, director of the Center for Autism Research & Translation and professor of pediatrics and physiology & biophysics. “Equally exciting, it also presents a target of a molecular class already well-established to be useful for drug discovery.”

Study results appear online in Translational Psychiatry, a Nature publication.

Autism spectrum disorder is a range of complex neurodevelopmental disorders affecting 2 percent of U.S. children. The social and economic burden of ASD is enormous, currently estimated at more than $66 billion per year in the U.S. alone. Drug development has proven problematic due to the limited understanding of the underlying causes of ASD, as demonstrated by the recent failure of several much anticipated drug trials.

There are also no current, reliable diagnostic biomarkers for ASD. Genetic research has identified hundreds of genes that are involved, which impedes diagnosis and, ultimately, drug development. There simply may be too many targets, each with too small an effect.

Many of these genes associated with ASD, however, have been found to be part of the same signaling pathway, and multiple defects in this pathway may converge to produce a large functional change.

The UCI scientists detected such a convergence in the IP3R calcium channel in an organelle called the endoplasmic reticulum. Organelles are membrane structures within cells with specialized cellular functions. According to Gargus, diseases of the organelles, such as the ER, are an emerging field in medicine, with several well-recognized neurological ailments linked to two other ones, the mitochondria and lysosomes.

The IP3R controls the release of calcium from the ER. In the brain, calcium is used to communicate information within and between neurons, and it activates a host of other cell functions, including ones regulating learning and memory, neuronal excitability and neurotransmitter release – areas known to be dysfunctional in ASD.
“We propose that the proper function of this channel and its signaling pathway is critical for normal performance of neurons and that this signaling pathway represents a key ‘hub’ in the pathogenesis of ASD,” said Parker, a fellow of London’s Royal Society and UCI professor of neurobiology & behavior, who studies cellular calcium signaling.

To see if IP3R function is altered across the autism spectrum, clinical researchers at The Center for Autism & Neurodevelopmental Disorders – which is affiliated with the Center for Autism Research & Translation – are currently expanding the study and have begun to examine children with and without typical ASD for the same signaling abnormalities. These patients undergo complete behavioral diagnostic testing, and sophisticated EEG, sleep and biochemical studies are performed. This includes the sequencing of their entire genome. Also, skin cell samples are cultured and made available to lab-based researchers for functional assays.

In the area of drug discovery, scientists at the Center for Autism Research & Translation continue to probe the IP3R channel, specifically how it regulates the level of neuron excitability. The brains of people who have autism show signs of hyperexcitability, which is also seen in epilepsy, a disorder increasingly found to be associated with ASD. Cells from individuals who have autism exhibit depressed levels of calcium signaling, and this might explain why these patients experience this hyperexcitability. By restoring the release of calcium from the IP3R, the researchers believe, they can apply a “brake” on this activity.

ER Stress

As we saw above, the endoplasmic reticulum (ER) is the cellular organelle in which protein folding, calcium homeostasis, and lipid biosynthesis occur. Stimuli such as oxidative stress, ischemic insult, disturbances in calcium homeostasis, and enhanced expression of normal and/or folding-defective proteins lead to the accumulation of unfolded proteins, a condition referred to as ER stress.

We know that we usually have oxidative stress in autism and we know that calsium homeostasis is disturbed, so it is not surprising if we found ER stress in autism.

The following paper is not open access but it does suggest that ER stress leads to impaired synaptic function and specifically GABA_B dysfunction.  If you respond well to Baclofen, you likely have a GABA_B dysfunction.  Based on anecdotal evidence I would suggest that people with Asperger’s and anxiety might well have ER stress, since they are the ones that respond well to baclofen.

Genetic factors and epigenetic factors for autism: Endoplasmic reticulum stress and impaired synaptic function

The molecular pathogenesis of ASD (autism spectrum disorder), one of the heritable neurodevelopmental disorders, is not well understood, although over 15 autistic-susceptible gene loci have been extensively studied. A major issue is whether the proteins that these candidate genes encode are involved in general function and signal transduction. Several mutations in genes encoding synaptic adhesion molecules such as neuroligin, neurexin, CNTNAP (contactin-associated protein) and CADM1 (cell-adhesion molecule 1) found in ASD suggest that impaired synaptic function is the underlying pathogenesis. However, knockout mouse models of these mutations do not show all of the autism-related symptoms, suggesting that gain-of-function in addition to loss-of-function arising from these mutations may be associated with ASD pathogenesis. Another finding is that family members with a given mutation frequently do not manifest autistic symptoms, which possibly may be because of gender effects, dominance theory and environmental factors, including hormones and stress. Thus epigenetic factors complicate our understanding of the relationship between these mutated genes and ASD pathogenesis. We focus in the present review on findings that ER (endoplasmic reticulum) stress arising from these mutations causes a trafficking disorder of synaptic receptors, such as GABA (γ-aminobutyric acid) B-receptors, and leads to their impaired synaptic function and signal transduction. In the present review we propose a hypothesis that ASD pathogenesis is linked not only to loss-of-function but also to gain-of-function, with an ER stress response to unfolded proteins under the influence of epigenetic factors.

I was surprised how much is known about ER stress, there is even a scientific journal devoted to it.

As is often the case, the literature is again full papers like the one below suggesting something, ER stress in this case, is a good drug target, but then do not suggest any drugs.

Endoplasmic Reticulum Stress As a Therapeutic Target in Cardiovascular Disease

Abstract

Cardiovascular disease constitutes a major and increasing health burden in developed countries. Although treatments have progressed, the development of novel treatments for patients with cardiovascular diseases remains a major research goal. The endoplasmic reticulum (ER) is the cellular organelle in which protein folding, calcium homeostasis, and lipid biosynthesis occur. Stimuli such as oxidative stress, ischemic insult, disturbances in calcium homeostasis, and enhanced expression of normal and/or folding-defective proteins lead to the accumulation of unfolded proteins, a condition referred to as ER stress. ER stress triggers the unfolded protein response (UPR) to maintain ER homeostasis. The UPR involves a group of signal transduction pathways that ameliorate the accumulation of unfolded protein by increasing ER-resident chaperones, inhibiting protein translation and accelerating the degradation of unfolded proteins. The UPR is initially an adaptive response but, if unresolved, can lead to apoptotic cell death. Thus, the ER is now recognized as an important organelle in deciding cell life and death. There is compelling evidence that the adaptive and proapoptotic pathways of UPR play fundamental roles in the development and progression of cardiovascular diseases, including heart failure, ischemic heart diseases, and atherosclerosis. Thus, therapeutic interventions that target molecules of the UPR component and reduce ER stress will be promising strategies to treat cardiovascular diseases. In this review, we summarize the recent progress in understanding UPR signaling in cardiovascular disease and its related therapeutic potential. Future studies may clarify the most promising molecules to be investigated as targets for cardiovascular diseases.

However all is not lost, a little digging uncovers several existing substances that affect ER Stress.

Atorvastatin, long part of my autism Polypill, is quite prominent.  Atorvastatin is lipophilic statin, which means it can better cross the blood brain barrier.  By chance it is the statin with the least side effects.

Lipophilic And Hydrophilic Statins Differentially Modulate Endoplasmic Reticulum Stress Response In Cardiac Myocytes

Statins inhibit HMG-CoA reductase, target mevalonic acid synthesis, and limit cholesterol biosynthesis. HMG-CoA reductase is expressed in the membrane of the endoplasmic reticulum (ER). Statins are prescribed to prevent cardiovascular events.

In cultured neonatal mouse cardiac myocytes the lipophilic statin atorvastatin and the hydrophilic statin pravastatin both up-regulated PDI, indicating unfolded protein response (UPR) meant to relieve ER stress. Only atorvastatin increased ER stress, growth arrest, and induced apoptosis via induction of CHOP, Puma, active Caspase-3 and PARP. Dose-dependent release of LDH was only observed in atorvastatin treated cells (1–10 μM). Hearts of mice treated with atorvastatin (5mg/kg/day for 7 months) showed protein aggresomes and autophagosomes when compared to vehicle treated controls. While atorvastatin changed mitochondrial ultrastructure, no differences in cardiac function, exercise ability or creatine kinase levels were found.

We show differential activation of ER stress by atorvastatin and pravastatin in cardiac myocytes. Our results provide a novel mechanism through which specific statins therapeutically modulate the balance of UPR/ER stress responses thereby possibly influencing cardiac remodeling.

Neuroprotective effects of atorvastatin against cerebral ischemia/reperfusion injury through the inhibition of endoplasmic reticulum stress

Cerebral ischemia triggers secondary ischemia/reperfusion injury and endoplasmic reticulum stress initiates cell apoptosis. However, the regulatory mechanism of the signaling pathway remains unclear. We hypothesize that the regulatory mechanisms are mediated by the protein kinase-like endoplasmic reticulum kinase/eukaryotic initiation factor 2α in the endoplasmic reticulum stress signaling pathway. To verify this hypothesis, we occluded the middle cerebral artery in rats to establish focal cerebral ischemia/reperfusion model. Results showed that the expression levels of protein kinase-like endoplasmic reticulum kinase and caspase-3, as well as the phosphorylation of eukaryotic initiation factor 2α, were increased after ischemia/reperfusion. Administration of atorvastatin decreased the expression of protein kinase-like endoplasmic reticulum kinase, caspase-3 and phosphorylated eukaryotic initiation factor 2α, reduced the infarct volume and improved ultrastructure in the rat brain. After salubrinal, the specific inhibitor of phosphorylated eukaryotic initiation factor 2α was given into the rats intragastrically, the expression levels of caspase-3 and phosphorylated eukaryotic initiation factor 2α in the were decreased, a reduction of the infarct volume and less ultrastructural damage were observed than the untreated, ischemic brain. However, salubrinal had no impact on the expression of protein kinase-like endoplasmic reticulum kinase. Experimental findings indicate that atorvastatin inhibits endoplasmic reticulum stress and exerts neuroprotective effects. The underlying mechanisms of attenuating ischemia/reperfusion injury are associated with the protein kinase-like endoplasmic reticulum kinase/eukaryotic initiation factor 2α/caspase-3 pathway.

Peroxisome Proliferator-Activated Receptor γ Activation Restores Islet Function in Diabetic Mice through Reduction of Endoplasmic Reticulum Stress and Maintenance of Euchromatin Structure^▿

ABSTRACT

The nuclear receptor peroxisome proliferator-activated receptor γ (PPAR-γ) is an important target in diabetes therapy, but its direct role, if any, in the restoration of islet function has remained controversial. To identify potential molecular mechanisms of PPAR-γ in the islet, we treated diabetic or glucose-intolerant mice with the PPAR-γ agonist pioglitazone or with a control. Treated mice exhibited significantly improved glycemic control, corresponding to increased serum insulin and enhanced glucose-stimulated insulin release and Ca²⁺ responses from isolated islets in vitro. This improved islet function was at least partially attributed to significant upregulation of the islet genes Irs1, SERCA, Ins1/2, and Glut2 in treated animals. The restoration of the Ins1/2 and Glut2 genes corresponded to a two- to threefold increase in the euchromatin marker histone H3 dimethyl-Lys4 at their respective promoters and was coincident with increased nuclear occupancy of the islet methyltransferase Set7/9. Analysis of diabetic islets in vitro suggested that these effects resulting from the presence of the PPAR-γ agonist may be secondary to improvements in endoplasmic reticulum stress. Consistent with this possibility, incubation of thapsigargin-treated INS-1 β cells with the PPAR-γ agonist resulted in the reduction of endoplasmic reticulum stress and restoration of Pdx1 protein levels and Set7/9 nuclear occupancy. We conclude that PPAR-γ agonists exert a direct effect in diabetic islets to reduce endoplasmic reticulum stress and enhance Pdx1 levels, leading to favorable alterations of the islet gene chromatin architecture.

PPAR-γ agonist pioglitazone is known to have a positive effect in some autism, but it does have side effects.

Other PPAR-γ agonists include Ibuprofen and Tangeretin (sold as Sytrinol).

ER stress plays a key role in diabetes and some obesity.

The role for endoplasmic reticulum stress in diabetes mellitus

Endoplasmic reticulum stress links obesity, insulin action, and type 2 diabetes

Conclusion

So as to Gargus’ question and the tittle of this post:

Is dysregulated IP₃R calcium signaling a nexus where genes altered in ASD converge to exert their deleterious effect?

The researchers are now looking at children with and without idiopathic autism to see if dysregulated IP₃R calcium is indeed a reliable marker.

Given so many things can lead to behavior diagnosed as autism, I think they will just identify an IP₃R cluster.  Hopefully it is a big one.  Then they can find a therapy to  release calcium from IP3R.

Where does ER stress fit into this picture?  Gargus briefly mentions stressors and unfolded protein responses:-

“In addition to its role in Ca2+ homeostasis, the ER serves as a key integrator of environmental stressors with metabolism and gene expression, as it mediates a host of broad ranging cell stress responses such as the heat shock and unfolded protein responses”

I think he is missing something here. 

The endoplasmic reticulum (ER) is the cellular organelle in which lipid biosynthesis occurs as well as protein folding and calcium homeostasis.

I suspect all three may be dysfunctional.  We have ample evidence of lipid abnormalities in autism and even lipid bilayer abnormalities. The Japanese research referred to above suggests protein folding dysfunction.  Note that what reduces ER stress (statins and tangeretin) also reduces cholesterol.

The good news is that plenty of therapeutic avenues already exist.

The other good news is that after 261 posts of this blog, so many pieces of the autism puzzle seem to be fitting together, not perfectly, but well enough to figure out how to treat multiple aspects of classic autism.

I did stumble across a recent quote by Ricardo Dolmetsch, formerly of Stanford and currently Global Head of Neuroscience at drug maker Novartis.  He also has a son with classic autism.  He was quoted again saying there are currently no drug treatments for core autism.  He knows a thousand times more about biology than me, but he is totally wrong to keep saying that there is nothing you can do beyond behavioral education and, if that fails, institutionalization.  I did write to him a while back and I do feel rather sorry for him, since it was his research on Timothy Syndrome that indirectly led to my Verapamil “discovery”.

Some people are just too clever (him, not me).

NMDAR hypo-function causing E/I imbalance in Autism and Schizophrenia – Baclofen, Sodium benzoate and Cinnamon (again)

Click on figure to enlarge

Source of text quoted:   E-I Balance and Human Diseases – from Molecules to Networking

Interpretation, extrapolation and graphic - Peter  

Today’s post is not the one I intended.

It nearly got tucked into long complicated one, that most people might not read.

I should caution that I am perhaps over-simplifying something that is extremely complicated, but no one fully understands the subject.

There is much talk in autism about the imbalance between excitatory and inhibitory processes. In this blog this is normally all about the inhibitory neurotransmitter, GABA, not functioning properly.

There is of course another side to the story.  The excitatory neurotransmitter Glutamate signals via receptors including the NMDA receptors.  If signaling via these receptors is either up or downregulated, the delicate balance between excitatory and inhibitory can again be lost.

What caught my interest was an experiment on mice that caused downregulation of (excitatory) NMDA signaling. This caused the famous E/I imbalance and resulting autistic behavior.

The interesting part is that the researchers normalized the imbalance and the autism not by targeting NMDA but by targeting GABA.  They used baclofen that acts on GABA_B receptors.  So they made the mouse autistic by adjusting NMDA (Glutamate) signaling, but recovered the mouse by adjusting the GABA signaling.  This is really quite compelling and made me look into the E/I imbalance again.

It also neatly explains why anti-epileptics, like valproate, when given during pregnancy can result in autistic off spring.  The Valproate increases GABA signaling, i.e. it inhibits neurons from firing too easily.  This reduced the tendency towards seizures.  It will unfortunately also enter the blood stream of the unborn child.  Here again it will shift the E/I balance towards inhibitory, but unlike in the mother, the E/I balance in the child was perfectly fine.  The valproate shifts the E/I balance out of the “safe zone” into the inhibitory danger zone.  This then can affects critical processes in the developing brain leading to autism.

   

NMDA hyper/hypo function

In earlier posts we have already seen that in autism NMDA activity be hyper (too much), hypo (too little) or normal.  There are drugs that can increase NMDA activity and others that reduce it.

In this post the research shows that reduced NMDAR signaling has been associated with schizophrenia, (some) autism and intellectual disability. 

A person with autism might be in this group, but as we saw in earlier posts on NMDA they might be in the opposite group and so have excessive NMDAR signaling.  A bit of trial and error would reveal whether the person was hyper, hypo or just right.  All three are possible in autism.   

GABA/Glutamate imbalance in Autism

The neurotransmitter GABA is supposed to be inhibitory and it is kept in balance by the excitatory neurotransmitter Glutamate. Glutamate binds to NMDA receptors and AMPA receptors.  GABA binds to GABA_A and GABA_B receptors.

In 2003 John Rubenstein and Michael Merzenich published a paper suggesting that autism might be the result of an E/I imbalance that disrupted both the development of the brain at critical periods and also was the underlying cause of some on-going autistic symptoms, including epilepsy (found in 30% of “old” autism) and what I refer to as pre-epilepsy (odd epileptiform activity without seizures – another 40% of “old” autism).  Plenty of subsequent research has supported their hypothesis.

Model of autism: increased ratio of excitation/inhibition in key neural systems

Once well-established theory for the development of autism is that the balance of various neurotransmitters is out of balance.  GABA, the key inhibitory neurotransmitter in the brain, ceases to inhibit the firing of neurons as it should.  The result is chaos in the brain.

In this blog we have concentrated one cause of this so called E/I (excitatory/Inhibitory) imbalance.  That cause is the presence of the NKCC1 transporter in the brain beyond the first few weeks of life.  This transporter leads to an excess of chloride inside the cells and this shifts GABA away from inhibitory to excitatory.  This then results in a GABA/Glutamate imbalance.  This impairs cognitive function and logically may be a cause of some seizures.

As Rubenstein and Merzenich observed, the hypothesis of E/I imbalance gives hope that drugs correcting this balance may treat autism. This has already been proved to be the case.

But there are other possible causes of E/I imbalance.  Today’s post is about one of those.  People who respond to the prescription drug Baclofen and the experimental drug Arbaclofen most likely are affected by this kind of E/I imbalance.

This blog has extensively covered the GABA_A-related cause of E/I imbalance, for which the prescription drug Bumetanide is effective.

Baclofen affects the GABA_B receptor.  One reader of this blog did tell us that in her patients with Asperger’s and anxiety did respond well to Baclofen.  They quite possibly have an E/I imbalance of the type covered in this post.  If so the underlying cause may well be NMDAR-hypofunction.

Reduced NMDAR signaling has been associated with schizophrenia, autism and intellectual disability.  By definition people with Asperger’s do not have and intellectual disability, but the Reduced NMDAR signaling may still be holding back their ever higher potential cognitive function.

As we will see, there may be a simple way to treat the NMDAR-hypofunction.

We have already covered this in an earlier post, when I talked about sodium benzoate and schizophrenia.

Sodium benzoate has multiple effects.

Sodium benzoate is a D-amino acid oxidase inhibitor. It will raise the levels of D-amino acids by blocking their metabolism and in doing so enhance NMDA function.  In doing so the E/I balance is shifted towards excitatory.

Sodium benzoate also increases the expression of a protein called DJ-1.  This is well known gene/protein because of its role in Parkinson’s disease.  The DJ-1 protein plays a supporting role to a key anti-oxidative stress defense called Nrf-1.

At times of oxidative stress, the body activated Nrf-1 which in then turns on key genes that need to respond to the stress.  In the absence of enough DJ-1, Nrf-1 is unable to sound the alarm and turn on those genes.

Sodium Benzoate is a common food additive (people with histamine intolerance “should be” allergic to it) but it is also a byproduct of eating cinnamon.  This is why cinnamon was shown to have therapeutic value in Parkinson’s disease.  Rather surprising it has also been shown to be beneficial in early Alzheimer’s disease.

In the earlier post we also saw that cinnamon had other useful effects like lowing cholesterol and improving insulin sensitivity.

We saw in the earlier post that it is important to use the “purer” cinnamon that come from Sri Lanka, since the related species from China that is commonly used by bakers does actually have side effects in large doses.

The Sri Lankan cinnamon may cost a bit more, but a one year supply is only about $15.

GABA_B-mediated rescue of altered excitatory–inhibitory balance, gamma synchrony and behavioral deficits following constitutive NMDAR-hypofunction

            Abstract

Reduced N-methyl-D-aspartate-receptor (NMDAR) signaling has been associated with schizophrenia, autism and intellectual disability. NMDAR-hypofunction is thought to contribute to social, cognitive and gamma (30–80 Hz) oscillatory abnormalities, phenotypes common to these disorders. However, circuit-level mechanisms underlying such deficits remain unclear. This study investigated the relationship between gamma synchrony, excitatory–inhibitory (E/I) signaling, and behavioral phenotypes in NMDA-NR1^neo−/− mice, which have constitutively reduced expression of the obligate NR1 subunit to model disrupted developmental NMDAR function. Constitutive NMDAR-hypofunction caused a loss of E/I balance, with an increase in intrinsic pyramidal cell excitability and a selective disruption of parvalbumin-expressing interneurons. Disrupted E/I coupling was associated with deficits in auditory-evoked gamma signal-to-noise ratio (SNR). Gamma-band abnormalities predicted deficits in spatial working memory and social preference, linking cellular changes in E/I signaling to target behaviors. The GABA_B-receptor agonist baclofen improved E/I balance, gamma-SNR and broadly reversed behavioral deficits. These data demonstrate a clinically relevant, highly translatable neural-activity-based biomarker for preclinical screening and therapeutic development across a broad range of disorders that share common endophenotypes and disrupted NMDA-receptor signaling.

Add-on Treatment of Benzoate for Schizophrenia A Randomized, Double-blind, Placebo-Controlled Trial of D-Amino Acid Oxidase Inhibitor

IMPORTANCE In addition to dopaminergic hyperactivity, hypofunction of the N-methyl-D-aspartate receptor (NMDAR) has an important role in the pathophysiology of schizophrenia. Enhancing NMDAR-mediated neurotransmission is considered a novel treatment approach. To date, several trials on adjuvant NMDA-enhancing agents have revealed beneficial, but limited, efficacy for positive and negative symptoms and cognition.

Another method to enhance NMDA function is to raise the levels of D-amino acids by blocking their metabolism. Sodium benzoate is a D-amino acid oxidase inhibitor.

OBJECTIVE To examine the clinical and cognitive efficacy and safety of add-on treatment of sodium benzoate for schizophrenia.

DESIGN, SETTING, AND PARTICIPANTS A randomized, double-blind, placebo-controlled trial in 2 major medical centers in Taiwan composed of 52 patients with chronic schizophrenia who had been stabilized with antipsychotic medications for 3 months or longer.

INTERVENTIONS Six weeks of add-on treatment of 1 g/d of sodium benzoate or placebo.

MAIN OUTCOMES AND MEASURES The primary outcome measure was the Positive and Negative Syndrome Scale (PANSS) total score. Clinical efficacy and adverse effects were assessed biweekly. Cognitive functions were measured before and after the add-on treatment.

RESULTS Benzoate produced a 21% improvement in PANSS total score and large effect sizes

(range, 1.16-1.69) in the PANSS total and subscales, Scales for the Assessment of Negative Symptoms–20 items, Global Assessment of Function, Quality of Life Scale and Clinical Global Impression and improvement in the neurocognition subtests as recommended by the National Institute of Mental Health’s Measurement and Treatment Research to Improve Cognition in Schizophrenia initiative, including the domains of processing speed and visual learning. Benzoate was well tolerated without significant adverse effects.

CONCLUSIONS AND RELEVANCE Benzoate adjunctive therapy significantly improved a variety of symptom domains and neurocognition in patients with chronic schizophrenia. The preliminary results show promise for D-amino acid oxidase inhibition as a novel approach for new drug development for schizophrenia.

Up-regulation of neurotrophic factors by cinnamon and its metabolite sodium benzoate: Therapeutic implications for neurodegenerative disorders

Abstract 

This study underlines the importance of cinnamon, a widely-used food spice and flavoring material, and its metabolite sodium benzoate (NaB), a widely-used food preservative and a FDA-approved drug against urea cycle disorders in humans, in increasing the levels of neurotrophic factors [e.g., brain-derived neurotrophic factor (BDNF) and neurotrophin-3 (NT-3)] in the CNS. NaB, but not sodium formate (NaFO), dose-dependently induced the expression of BDNF and NT-3 in primary human neurons and astrocytes. Interestingly, oral administration of ground cinnamon increased the level of NaB in serum and brain and upregulated the levels of these neurotrophic factors in vivo in mouse CNS. Accordingly, oral feeding of NaB, but not NaFO, also increased the level of these neurotrophic factors in vivo in the CNS of mice. NaB induced the activation of protein kinase A (PKA), but not protein kinase C (PKC), and H-89, an inhibitor of PKA, abrogated NaB-induced increase in neurotrophic factors. Furthermore, activation of cAMP response element binding (CREB) protein, but not NF-κB, by NaB, abrogation of NaB-induced expression of neurotrophic factors by siRNA knockdown of CREB and the recruitment of CREB and CREB-binding protein to the BDNF promoter by NaB suggest that NaB exerts its neurotrophic effect through the activation of CREB. Accordingly, cinnamon feeding also increased the activity of PKA and the level of phospho-CREB in vivo in the CNS. These results highlight a novel neutrophic property of cinnamon and its metabolite NaB via PKA – CREB pathway, which may be of benefit for various neurodegenerative disorders.

There are several advantages of NaB and cinnamon over other proposed anti-neurodegenerative therapies. First, both NaB and cinnamon are fairly nontoxic. Cinnamon has been widely used as flavoring material and spice throughout the world for centuries. Cinnamon is metabolized to NaB. NaB is excreted through the urine, if in excess.

Second, cinnamon and NaB can be taken orally, the least painful route.

Third, cinnamon and NaB are very economical compared to other existing anti-neurodegenerative therapies.

Fourth, after oral administration, NaB rapidly diffuses through the BBB. Similarly, after oral administration of cinnamon, we also detected NaB in the brain

Fifth, glycine toxicity is a problem in different neurological diseases because for movement disorders, glycine is one of the factors for inhibiting motor neurons. When impaired, glycinergic inhibition leads to spastic and hypertonic disorders such as featured in PD, multiple sclerosis (MS) and spinal cord trauma. NaB is known to combine with glycine to produce hippurate, a compound that is readily excreted in the urine. Because PD and MS patients exhibit significant elevation in plasma level of glycine, NaB and cinnamon may have added benefits for MS and PD.

Benzoate, a D-amino acid oxidase inhibitor, for the treatment of early-phase Alzheimer disease: a randomized, double-blind, placebo-controlled trial.

Abstract 

BACKGROUND: 

N-methyl-D-aspartate receptor (NMDAR)-mediated neurotransmission is vital for learning and memory. Hypofunction of NMDAR has been reported to play a role in the pathophysiology of Alzheimer disease (AD), particularly in the early phase. Enhancing NMDAR activation might be a novel treatment approach. One of the methods to enhance NMDAR activity is to raise the levels of NMDA coagonists by blocking their metabolism. This study examined the efficacy and safety of sodium benzoate, a D-amino acid oxidase inhibitor, for the treatment of amnestic mild cognitive impairment and mild AD.

METHODS:
We conducted a randomized, double-blind, placebo-controlled trial in four major medical centers in Taiwan. Sixty patients with amnestic mild cognitive impairment or mild AD were treated with 250-750 mg/day of sodium benzoate or placebo for 24 weeks. Alzheimer's Disease Assessment Scale-cognitive subscale (the primary outcome) and global function (assessed by Clinician Interview Based Impression of Change plus Caregiver Input) were measured every 8 weeks. Additional cognition composite was measured at baseline and endpoint.

RESULTS:
Sodium benzoate produced a better improvement than placebo in Alzheimer's Disease Assessment Scale-cognitive subscale (p = .0021, .0116, and .0031 at week 16, week 24, and endpoint, respectively), additional cognition composite (p = .007 at endpoint) and Clinician Interview Based Impression of Change plus Caregiver Input (p = .015, .016, and .012 at week 16, week 24, and endpoint, respectively). Sodium benzoate was well-tolerated without evident side-effects.

CONCLUSIONS:
Sodium benzoate substantially improved cognitive and overall functions in patients with early-phase AD. The preliminary results show promise for D-amino acid oxidase inhibition as a novel approach for early dementing processes.

The implications

There are numerous implications, since cinnamon is very cheap and Sri Lanka Cinnamon is seen as very safe.

·        Take cinnamon to lower the risk of Parkinson’s and Alzheimer’s

·        Take cinnamon if you have got Parkinson’s or Alzheimer’s

·        Take cinnamon if you are type 1 or 2 diabetic to improve insulin sensitivity

·        Take cinnamon if you have high cholesterol (perhaps you do not like Statins)

·        Rather unexpectedly, it is suggested that cinnamon should also help multiple sclerosis (MS) because it reduces glycine toxicity which otherwise leads to spastic and hypertonic disorders

·        Trial cinnamon if you have Asperger’s, Schizophrenia, Autism, MR/ID and even COPD

·        Trial cinnamon if (ar)baclofen positively affects your cognitive or emotional function.

Note that some people diagnosed with “autism” have the opposite NMDA dysfunction, they have too much signaling rather than too little.

One method to enhance NMDA function is to raise the levels of D-amino acids by blocking their metabolism. Sodium benzoate is a D-amino acid oxidase inhibitor. Cinnamon is metabolized in the body to sodium benzoate.

Giving cinnamon to someone with hyperfunction of NMDA, should make their symptoms worse.

Sodium Benzoate/Cinnamon also increases the level of BDNF

It is thought that BDNF  increases excitatory synaptic signaling partly

http://jn.physiology.org/content/88/2/595.long

“BDNF increases spontaneous network activity by suppressing GABAergic inhibition, the site of action of BDNF is predominantly postsynaptic, BDNF-induced suppression of GABAergic synaptic transmission is caused by acute downregulation of GABA_A receptors, and BDNF effects are mediated by its TrkB receptor and require PKC activation in the postsynaptic cell.”

BDNF is commonly elevated in autism.

So you would then expect that some people with autism/schizophrenia would benefit while others would not.

Since some people are allergic to sodium benzoate it would wise to start with a tiny amount of cinnamon.

Cinnamon has been used medicinally for centuries.

Cassia cinnamon from China, Vietnam or Indonesia contains coumarin.  Courmarin is not good for you.  Cassia cinnamon is what is normally used in food products, to save money.

In an earlier post:

Altered Homeostasis in Autism: Cl-, K+, Ca2+, and quite possibly Zn2+

we saw that Clioquinol and  D-Cycloserine should help those with those with reduced NMDAR function.

Those with elevated NMDAR function would benefit from Memantine and Ketamine.

So logically Clioquinol and  D-Cycloserine should help schizophrenia:-

Trial of D-Cycloserine in Schizophrenia

Nobody seems to have tried Clioquinol on schizophrenia.

Baclofen for Schizophrenia

It is would also be logical that if some people with schizophrenia do have reduced NMDAR signaling then Baclofen should also help them, just as Sodium Benzoate has been shown to do and therefore cinnamon should.

Going back to 1977 Baclofen was indeed found to be effective in some types of schizophrenia

Baclofen in the treatment of schizophrenia: a pilot study.

Conclusion

I think that Cinnamon is a better bet than Sodium Benzoate, because you actually may have other substances involved, not just NaB.

The dose at which cinnamon shows tangible biological effects in humans (lowing cholesterol etc.) is around 3g a day.  For those who can swallow capsules, that would be 3 large (size 000) gelatin capsules a day, otherwise you have to find a way of eating a teaspoonful of cinnamon a day.

According to the research “cinnamon has been widely used as flavoring material and spice throughout the world for centuries. Cinnamon is metabolized to NaB. NaB is excreted through the urine, if in excess.”  So it looks a safe therapy, whether it helps autism will depend on the specific biology of that individual.