PAK inhibitors and potentially treating some Autism using Grandpa’s Medicine Cabinet

I wrote several posts about why PAK1 inhibitors should be beneficial in some autism and indeed some schizophrenia.

We also saw that PAK1-blocking drugs could be potentially useful for the treatment of neurofibromatosis type 2, in addition to RAS-induced cancers and neurofibromatosis type 1.

One problem with drugs developed for cancer is that, even if they finally get approved, they tend to be ultra-expensive.  Production volumes are low because even if they “work” they do not prolong life for so long and cancer has numerous sub-types.

Cheap drugs are ones used to treat common chronic conditions like high blood pressure, high cholesterol and indeed treatment of male lower urinary tract symptoms (LUTS), like benign prostatic hyperplasia (BPH).

A small number of readers of this blog have confirmed the beneficial effect of PAK inhibitors in their specific sub-types of autism.  The problem is that there are no potent PAK1 inhibitors suitable for long term use that are readily available.

The anti-parasite drug Ivermectin is an extremely cheap PAK1 inhibitor, but cannot be used long term, due to its other effects.

Propolis containing CAPE (Caffeic Acid Phenethyl Ester) is a natural PAK1 inhibitor, but may not be sufficiently potent as is reported by people with neurofibromatosis.

You would think somebody would just synthesize CAPE (Caffeic Acid Phenethyl Ester) artificially and then higher doses could be achieved.

PAK Inhibitors and Treatment of Prostate Enlargement

I was rather surprised that research has recently been published suggesting that PAK inhibitors could be used to treat the prostate enlargement, common in most older men. 

P21-Activated Kinase Inhibitors FRAX486 and IPA3: Inhibition of Prostate Stromal Cell Growth and Effects on Smooth Muscle Contraction in the Human Prostate

Abstract

Prostate smooth muscle tone and hyperplastic growth are involved in the pathophysiology and treatment of male lower urinary tract symptoms (LUTS). Available drugs are characterized by limited efficacy. Patients’ adherence is particularly low to combination therapies of 5α-reductase inhibitors and α₁-adrenoceptor antagonists, which are supposed to target contraction and growth simultaneously. Consequently, molecular etiology of benign prostatic hyperplasia (BPH) and new compounds interfering with smooth muscle contraction or growth in the prostate are of high interest. Here, we studied effects of p21-activated kinase (PAK) inhibitors (FRAX486, IPA3) in hyperplastic human prostate tissues, and in stromal cells (WPMY-1). In hyperplastic prostate tissues, PAK1, -2, -4, and -6 may be constitutively expressed in catecholaminergic neurons, while PAK1 was detected in smooth muscle and WPMY-1 cells. Neurogenic contractions of prostate strips by electric field stimulation were significantly inhibited by high concentrations of FRAX486 (30 μM) or IPA3 (300 μM), while noradrenaline- and phenylephrine-induced contractions were not affected. FRAX486 (30 μM) inhibited endothelin-1- and -2-induced contractions. In WPMY-1 cells, FRAX486 or IPA3 (24 h) induced concentration-dependent (1–10 μM) degeneration of actin filaments. This was paralleled by attenuation of proliferation rate, being observed from 1 to 10 μM FRAX486 or IPA3. Cytotoxicity of FRAX486 and IPA3 in WPMY-1 cells was time- and concentration-dependent. Stimulation of WPMY-1 cells with endothelin-1 or dihydrotestosterone, but not noradrenaline induced PAK phosphorylation, indicating PAK activation by endothelin-1. Thus, PAK inhibitors may inhibit neurogenic and endothelin-induced smooth muscle contractions in the hyperplastic human prostate, and growth of stromal cells. Targeting prostate smooth muscle contraction and stromal growth at once by a single compound is principally possible, at least under experimental conditions.

It looks like a PAK inhibitor could potentially solve both the key problems in BPH and so replace the current therapies.

Existing Drugs for LUTS/BPH

Undoubtedly someone is going to wonder whether existing drugs for LUTS/BPH might improve autism.  This is actually possible, but totally unrelated to PAK1 inhibition and RASopathies.

Existing drugs are in two classes, 5α-reductase inhibitors and α₁-adrenoceptor antagonists.

α-adrenoceptor antagonists

Alpha blockers relax certain muscles and help small blood vessels remain open. They work by keeping the hormone norepinephrine (noradrenaline) from tightening the muscles in the walls of smaller arteries and veins, which causes the vessels to remain open and relaxed. This improves blood flow and lowers blood pressure.

Because alpha blockers also relax other muscles throughout the body, these medications can help improve urine flow in older men with prostate problems.

Selective α₁-adrenergic receptor antagonists are often used in BPH because it is the α₁-adrenergic receptor that is present in the prostate.

 α ₂-adrenergic receptors are present elsewhere in the body

Alpha-2 blockers are used to treat anxiety and post-traumatic stress disorder (PTSD). They decrease sympathetic outflow from the central nervous system. Post-traumatic stress disorder is an anxiety disorder that is theorized to be related to a hyperactive sympathetic nervous system.

Alpha-2 receptor agonists for the treatment of post-traumatic stress disorder

So a nonselective alpha blocker, like one given to an older man with high blood pressure and BPH, might well have an effect on some kinds of anxiety.

You would think that a selective alpha 2 blocker might be interesting, how about Idazoxan?

Idazoxan is a drug which is used in research. It acts as both a selective α2 adrenergic receptor antagonist, and an antagonist for the imidazoline receptor. Idazoxan has been under investigation as an antidepressant, but it did not reach the market as such. More recently, it is under investigation as an adjunctive treatment in schizophrenia. Due to its alpha-2 receptor antagonism it is capable of enhancing therapeutic effects of antipsychotics, possibly by enhancing dopamine neurotransmission in the prefrontal cortex of the brain, a brain area thought to be involved in the pathogenesis of schizophrenia.

Mirtazapine is a cheap generic drug used at high doses for depression.  It happens to be a selective alpha 2 blocker, but it has numerous other effects as well.  One reader of this blog does respond very well to Mirtazapine.

So realistically in Grandpa’s medicine cabinet there might a selective alpha 1 agonist or a non-selective alpha agonist, it is the latter type that might have an effect on some kinds of autism.

5α-reductase inhibitors

The pharmacology of 5α-reductase inhibition involves the binding of NADPH to the enzyme followed by the substrate. Specific substrates include testosterone, progesterone, androstenedione, epitestosterone, cortisol, aldosterone, and deoxycorticosterone.

Beyond being a catalyst in testosterone reduction, 5α-reductase isoforms I and II reduce progesterone to 5α-dihydroprogesterone (5α-DHP) and deoxycorticosterone to dihydrodeoxycorticosterone (DHDOC).

In vitro and animal models suggest subsequent 3α-reduction of DHT, 5α-DHP and DHDOC lead to neurosteroid metabolites with effect on cerebral function.

These neurosteroids, which include allopregnanolone, tetrahydrodeoxycorticosterone (THDOC), and 5α-androstanediol, act as potent positive allosteric modulators of GABA_A receptors, and have anticonvulsant, antidepressant, anxiolytic, prosexual, and anticonvulsant effects.

Inhibition of 5α-reductase results in decreased conversion of testosterone to DHT.

This, in turn, results in slight elevations in testosterone and estradiol levels. 

In BPH, DHT acts as a potent cellular androgen and promotes prostate growth; therefore, it inhibits and alleviates symptoms of BPH. In alopecia, male and female-pattern baldness is an effect of androgenic receptor activation, so reducing levels of DHT also reduces hair loss.

A new look at the 5alpha-reductase inhibitor finasteride

Finasteride is the first 5alpha-reductase inhibitor that received clinical approval for the treatment of human benign prostatic hyperplasia (BPH) and androgenetic alopecia (male pattern hair loss). These clinical applications are based on the ability of finasteride to inhibit the Type II isoform of the 5alpha-reductase enzyme, which is the predominant form in human prostate and hair follicles, and the concomitant reduction of testosterone to dihydrotestosterone (DHT). In addition to catalyzing the rate-limiting step in the reduction of testosterone, both isoforms of the 5alpha-reductase enzyme are responsible for the reduction of progesterone and deoxycorticosterone to dihydroprogesterone (DHP) and dihydrodeoxycorticosterone (DHDOC), respectively. Recent preclinical data indicate that the subsequent 3alpha-reduction of DHT, DHP and DHDOC produces steroid metabolites with rapid non-genomic effects on brain function and behavior, primarily via an enhancement of gamma-aminobutyric acid (GABA)ergic inhibitory neurotransmission. Consistent with their ability to enhance the action of GABA at GABA(A) receptors, these steroid derivatives (termed neuroactive steroids) possess anticonvulsant, antidepressant and anxiolytic effects in addition to altering aspects of sexual- and alcohol-related behaviors. Thus, finasteride, which inhibits both isoforms of 5alpha-reductase in rodents, has been used as a tool to manipulate neuroactive steroid levels and determine the impact on behavior. Results of some preclinical studies and clinical observations with finasteride are described in this review article. The data suggest that endogenous neuroactive steroid levels may be inversely related to symptoms of premenstrual and postpartum dysphoric disorder, catamenial epilepsy, depression, and alcohol withdrawal.

This would suggest that a 5α-reductase inhibitor, like finasteride, that might be among Grandpa’s tablets might very well have an effect on someone with GABAa dysfunction, this includes very many people with autism, schizophrenia and Down Syndrome.

Whether the effect will be good or bad is hard to say, and may well depend on whether other drugs that target GABA or NMDA receptors are being used. Due to their other effects, 5α-reductase inhibitors are usually only used in adults.

Merck developed a lower dose form of finasteride, called Prospecia to treat baldness, usually in men.  It is 20% the normal potency used for BPH.

Side effects

The current BPH drugs cause side effects in some people.  PAK1 inhibitors may also have some side effects.

Conclusion

Going back in the days of living with your extended family might make treating many people’s autism much simpler.  It looks like many older people’s drugs can be repurposed for some types of autism (ion channel modifying diuretics, calcium channel blockers, statins, even potentially intranasal insulin in some).  Because older people’s drugs are so widely used they are well understood and inexpensive.  

Clearly the research on PAK inhibitors for LUTS/BPH is at an early stage, but there is a huge potential market.   A widely available PAK1 inhibitor might be a big help to some people with autism, neurofibromatosis, other RASopathies, not just Grandpa’s prostate.

In addition to FRAX486 and IPA3, why doesn’t someone try synthetic CAPE, i.e. without the bees, as a PAK inhibitor?

Bioactivity and chemical synthesis of caffeic acid phenethyl ester and its derivatives.

There is far more chance of a PAK1 inhibitor coming to market for LUTS/BPH, or certain cancers than for autism.  That is a fact of life.

As for 5α-reductase inhibitors, like finasteride, we know from Hardan’s study on Pregnenolone at Stanford that this hormone can have a positive effect and we know that various natural steroid metabolites will modulate GABA subunits.  So it is quite likely that finasteride is going have a behavioral effect.  Perhaps Hardan would like to trial finasteride 5mg and 1mg (Prospecia) in some adults with autism. I suspect it will make some people “worse” and others somewhat “better”; so please do not report the “average” response, highlight the nature of the positive responders.

It’s not Autism, it’s Sotos Syndrome – and more about GABA therapies

 Peter the wild boy, with Pitt Hopkins Syndrome

I recently returned from a 25 year class reunion; of the 200 or so class members about 120 turned up. Of the 200 we know that at least 5 have a son with autism and at least one has a nephew with autism.  So I had my first ever “autism lunch” discussing all those tricky issues we are left to deal with.

What was immediately apparent was how different each child’s “autism” was and that none of them were the autism-lite variants that are now being so widely diagnosed in older children. or even adults .  Of the six, two are non-verbal, one is institutionalized, yet one talks a lot.  Three sets of parents are big ABA fans and one child did not respond to ABA.

You may be wondering about that high incidence of autism.  This was not a gathering of science boffins or mathematicians; this was at a business school.  One thing is obvious, you can correlate some autism incidence with educational level.  You can connect all sorts of measures of IQ to autism, from having a math prodigy in the family, to having professors at Ivy league type Universities, particularly in Mathematics.  It does appear to be true that the so-called clever genes are also associated with some types of autism.

I presume that if my science-only university organized such events the incidence of autism would be even higher.

On the way back home we met an acquaintance at the airport, who was telling us all about his son with Sotos Syndrome.  "It is not autism", we were informed, but then I am not quite sure what is.  When you look it up, many of the symptoms look just like autism.  In fact, it is a single gene dysfunction that leads to gigantism and various elements of autism.

This brings me to the painting above of Peter the Wild Boy; it is not me I should point out.  The above Peter was a German boy who came to live in England in the 18^th Century; he was non-verbal and is now thought to have had Pitt Hopkins Syndrome.  Like Sotos, this is another very rare single gene disorder.

We have already come across Rett Syndrome, which for some reason is treated as autism.

Fragile X is thought of as a syndrome where autism can be comorbid.

Timothy Syndrome is fortunately extremely rare, but I have already drawn on it in my own research into autism.

There are also autism related disorders involving multiple genes.

Prader–Willi syndrome  is a rare genetic disorder in which seven genes (or some subset thereof) on chromosome 15 (q 11–13) are deleted or unexpressed (chromosome 15q partial deletion) on the paternal chromosome.  If the maternally derived genetic material from the same region is affected instead, the sister Angelman Syndrome is the result.

The most frequent disorder caused by known multiple gene overexpression is Down Syndrome.  We saw in earlier post that DS is caused by the presence of all or part of a third copy of chromosome 21.  This results in over-expression of some 300 genes.

Why So Many Syndromes

Even before the days of genetic testing, these syndromes had been identified.  How could that be?  Each syndrome is marked by clear physical differences.

These physical differences where used to identify those affected.

Within autism too, sometimes there are physical differences.  Big heads, small heads, slim stature or heavy stature, advanced bone age or retarded bone age.

So many syndromes , but no therapies

Many of the rare syndromes have their own foundations funding research, mainly on the basis that if there is a known genetic dysfunction there should be matching therapy somewhere.

As of today, there are no approved therapies for any of these syndromes.

The Futility of Genetic Research?

A great deal of autism research funding goes into looking for target genes.  The idea goes that once you know which gene is the problem you can work out how to correct it.  There are numerous scientific journal dedicated to this approach.

Since no progress has been made in treating known genetic conditions leading to “autism”, is all this research effort well directed?  Some clever researchers think it is not.

All I can do is make my observations from the side lines.

What do Down Syndrome, Autism and Pitt Hopkins Syndrome all have in common?

In at least some of those affected, they have the identical excitatory-inhibitory imbalance of GABA, that can be corrected by Bumetanide.

If you did whole exome genetic testing on the responders with these three conditions you would not find a common genetic dysfunction; and yet they respond to the same therapy.

I am actually all for continued genetic research, but those involved have got to understand its limitations, as well as its potential.

More on GABA

This post returns to the theme of the dysfunctional GABA neurotransmitter because the research indicates it is present in numerous of the above-mentioned conditions. 

Table 1.  Summary of GABAA signaling alterations in neurodevelopmental disorders (click for the full Table)

·        Autism

·        Fragile X

·        Rett Syndrome

·        Down Syndrome

·        Neurofibromatosis type 1

·        Tourette syndrome

·        Schizophrenia

·        Tuberous sclerosis complex (TSC)

·        Prader-Willi syndrome

·        Angelman Syndrome

Based on feedback to me, we should add Pitt Hopkins Syndrome to the above list.

The GABA dysfunction is not the same in all the above conditions, but at least in some people, Bumetanide is effective in cases of autism, Down Syndrome and Pitt Hopkins Syndrome.  I suspect that since it works in mice with Fragile-X , it will work in at least some humans.

GABA_A has already been covered in some depth in this blog, but I am always on the lookout for more on this subject, since interventions are highly effective.  It is complicated, but for those of you using Bumetanide, Low Dose Clonazepam, Oxytocin and some even Diamox, the paper below will be of interest.

Modulation of GABAergic transmission indevelopment and neurodevelopmental disorders: investigating physiology andpathology to gain therapeutic perspectives

Regular readers will know that in autism high levels of chloride Cl⁻ inside the neuron have been shown to make GABA excitatory rather than inhibitory.  This leads to neurons firing too frequently;  this results in effects ranging from anxiety to seizures and with reduced cognitive functioning.  Therapies revolve around reducing chloride levels, this can be done by restricting the flow in ,or by increasing the flow out.  The Na⁺/K⁺/Cl⁻ cotransporter NKCC1  imports Cl⁻ into the neuron.  By blocking this transporter using Bumetanide you can achieve lower Cl⁻ within the neuron, but with this drug you also affect NKCC2, an isoform present in the kidney, which is why Bumetanide is a diuretic.  Some experimental drugs are being tested that block NKCC1 without affecting NKCC2 and better cross the blood brain barrier. 

The interesting new approach is to restore Cl⁻ balance by increasing KCC2 expression at the plasma membrane.  This means increasing the number of transporters that carry  Cl⁻  out of the neurons.

Chloride extrusion enhancers as novel therapeutics for neurological diseases

In the Modulation of GABAergic transmission paper there is no mention of acetazolamide (Diamox) which I suggested in my posts could also reduce Cl⁻, but via the AE3 exchanger.  This would explain why Diamox can reduce seizures in some people.

The paper does mention oxytocin and it does occur to me that babies born via Cesarean/Caesarean section will completely miss this surge of the oxytocin hormone.  This oxytocin surge is suggested to be key to the GABA switch, which should occur soon after birth when GABA switches from excitatory to inhibitory.  In much autism this switch never takes place.

That would suggest that perhaps all babies born via Caesarean section should perhaps receive an artificial dose of oxytocin at birth.  This might then reduce the incidence of GABA dysfunctions in later life, which would include autism and some epilepsy.

Indeed, children born by Caesarean section (CS) are 20% more likely to develop autism.

Association Between Obstetric Mode of Delivery and Autism Spectrum Disorder - :  A Population-Based Sibling Design Study

Conclusions and Relevance  This study confirms previous findings that children born by CS are approximately 20% more likely to be diagnosed as having ASD. However, the association did not persist when using sibling controls, implying that this association is due to familial confounding by genetic and/or environmental factors.

So as not to repeat the vaccine/autism scare, the researchers do not say that Caesarean section leads to more autism, rather that the kinds of people who are born by Caesarean section already had an elevated risk of autism.  This is based on analysing sibling pairs, but I do not entirely buy into that argument.  They do not want to scare people from having a procedure that can be life-saving for mother and baby.

If you look at it rationally, you can see that the oxytocin surge at birth is there for an evolutionary reason.  It is very easy to recreate it with synthetic oxytocin.

Another interesting point is in the conflict of interest statement:-

Laura Cancedda is on the Provisional Application: US 61/919,195, 2013. Modulators of Intracellular Chloride Concentration For Treating An Intellectual Disability

Regular readers will note that in this blog we have known for some time that modifying GABA_A leads to improved cognitive function.  I even suggested to Ben-Ari that IQ should be measured in their autism trials for Bumetanide.  IQ is much less subjective than measures of autism.

Conclusion

My conclusion is that while genetic testing has its place, it is more productive to look at identifying and treating the downstream dysfunctions that are shared by many individual genetic dysfunctions.

By focusing on individual genes there is a big risk of just giving up, so if you have Pitt Hopkins Syndrome, like Peter the Wild Boy, it is a single gene cause of “autism” and there is no known therapy.  Well it seems that it shares downstream consequences with many other types of autism, so it is treatable after all.

I also think more people need to consider that cognitive dysfunction (Intellectual Disability/MR) may indeed be treatable, and not just via GABA; so good luck to Laura Cancedda.

Gingerols and Statins (as Farnesyltransferase inhibitors) for RASopathies and Some Autism

Today’s post was driven by another attempt not to take a statin.

Statins are among the world’s most prescribed, and yet most maligned, drugs.  Hundreds of millions of people take a statin drug every day to lower their cholesterol, but a small, vocal minority complain about muscle pains, memory loss and even type 2 diabetes.

Since my Polypill is evidently a therapy, and not a cure, for autism, the odds are that it will be needed life-long.  Regardless of the apparent lack of side-effects, nobody should be taking drugs/supplements that are not really needed.  Atorvastatin (Lipitor/Sortis) is part of my Polypill for the type of autism affecting Monty, aged 11, with ASD.

Every time I stop the statin part of my Polypill therapy, I end up starting it again after only a one day break.  I notice all sorts of little behavioral changes that I really do not want to see.   

These changes involve loss of initiative, flexibility and motivation.  I really do not see how these would be measured in any existing behavioral assessment of autism.  These little changes make a big difference in daily life, so-called adaptive behavior.

In case you are wondering, the types of people with autism that I think might benefit from statins, have high cholesterol and some of the following:-

·        Non-verbal, or people who are slightly verbal, but choose not to speak

·        Poor ability to generalize skills already mastered in 1:1 therapy

·        Great difficulty in separating

·        Great difficulty in coping with change

As with some other elements of the Polypill, there are numerous reasons why statins could/should help in autism.  Today I found yet another one and an interesting non-drug alternative.

Why Statins?

I originally choose statins as a possible therapy, based on their ability to control pro-inflammatory cytokines (e.g. cytokine storms), and their known neuro-protective properties (e.g. reduce mortality after a traumatic brain injury).

I then noted they also affect some autism target genes, such as PTEN and BCL-2.

I did also note that statins were being researched to treat Neurofibromatosis, a single gene condition that is frequently comorbid with an “autism” diagnosis.

Today’s post is really about why statins should help in Neurofibromatosis and what else shares the same mechanism of action. 

Putting aside cytokines, PTEN and BCL-2, this new mechanism (excessive RAS/ERK signaling) might also be active in broader autism and Intellectual Disability / MR.

The other recent development was a study at UCLA that looked at a rare condition called Noonan Syndrome.  Noonan Syndrome and Neurofibromatosis are members of a group of conditions called RASopathies.

The RASopathies are developmental syndromes caused by mutations in genes that alter the Ras subfamily and Mitogen-activated protein kinases that control signal transduction.

Statins reverse learning disabilities caused by genetic disorder

Drawing upon Silva’s previous research on neurofibromatosis 1, another Ras-influenced disease, the UCLA team treated the mice with lovastatin, an FDA-approved statin drug currently in wide clinical use.

When adult mice with Noonan were treated with lovastatin in the UCLA study, the drop in Ras activity dramatically improved their memory and ability to remember objects and navigate mazes.

“We were amazed to see that statin treatment restored the adult animals’ cognitive functions to normal. Traditionally, science assumes that therapy needs to start in the fetal stage to be effective,” explained Silva. “Our research suggests that the leading gene mutation responsible for Noonan syndrome plays critical roles not only in fetal development, but also in how well the adult brain functions.”

According to Silva, UCLA’s approach could help the estimated 35 million Americans who struggle with learning disabilities

The paper itself:-

Mechanism and treatment for learning and memory deficits in mouse models of Noonan syndrome

RAS/ERK Inhibitors

For those of you more interested in the implications, rather than the science, here they are.

Known RAS inhibitors include:-

·        Statins, the popular cholesterol reducing drugs.  The “lipophilic” statins (Simvastatin, Lovastatin, Atorvastatin) can cross the blood brain barrier

·        Farnesyltransferase inhibitors, these are mainly anti-cancer research compounds, but one is the flavonoid Gingerol

Gingerol, is the active constituent of fresh ginger.  It is normally found as a pungent yellow oil, but also can form a low-melting crystalline solid.

Cooking ginger transforms gingerol into zingerone, which is less pungent and has a spicy-sweet aroma. When ginger is dried, gingerol undergoes a dehydration reaction forming shogaols, which are about twice as pungent as gingerol. This explains why dried ginger is more pungent than fresh ginger.

Ginger also contains 8-gingerol, 10-gingerol, and 12-gingerol.

Physiological effects

Gingerol seems to be effective in an animal model of rheumatoid arthritis.

Gingerol has been investigated for its effect on cancerous tumors in the bowel, breast tissue, ovaries, the pancreas, among other tissues, with positive results.

Neurofibromatosis, Behavioral dysfunction and RAS signaling

Neurofibromatosis Type 1: Modeling CNS Dysfunction

Neurofibromatosis type 1 (NF1) is the most common monogenic disorder in which individuals manifest CNS abnormalities. Affected individuals develop glial neoplasms (optic gliomas, malignant astrocytomas) and neuronal dysfunction (learning disabilities, attention deficits). Nf1 genetically engineered mouse models have revealed the molecular and cellular underpinnings of gliomagenesis, attention deficit, and learning problems with relevance to basic neurobiology. Using NF1 as a model system, these studies have revealed critical roles for the NF1 gene in non-neoplastic cells in the tumor microenvironment, the importance of brain region heterogeneity, novel mechanisms of glial growth regulation, the neurochemical bases for attention deficit and learning abnormalities, and new insights into neural stem cell function. Here we review recent studies, presented at a symposium at the 2012 Society for Neuroscience annual meeting, that highlight unexpected cell biology insights into RAS and cAMP pathway effects on neural progenitor signaling, neuronal function, and oligodendrocyte lineage differentiation.

Working memory, which, like attention, depends on intact prefrontal circuitry, is also impaired in both Nf1^+/− mice and in individuals with NF1. Functional imaging studies showed that the working memory impairments of NF1 subjects correlated with hypoactivation in the prefrontal cortex, which may reflect increased GABA-mediated inhibition in prefrontal cortical circuits of Nf1^+/− mice. Remarkably, a dose of a GABA receptor inhibitor (picrotoxin), which caused deficits in working memory in control mice, rescued the working memory deficits of Nf1^+/− mice, a result consistent with the hypothesis that increased inhibition is at the root of the working memory deficits associated with NF1.

Increases in RAS/ERK signaling in Nf1^+/− mice have been implicated in the working memory, attention, and spatial learning deficits of these mice. Genetic and pharmacological manipulations that target the RAS/ERK signaling pathway were shown to rescue the physiological and behavioral deficits of Nf1^+/− mice. Importantly, pharmacological manipulations that impair the isoprenylation of RAS (statins, farnesyl transferase inhibitors), and therefore decrease the levels of RAS/ERK signaling, also rescue key electrophysiological and behavioral phenotypes of Nf1^+/− mice. Indeed, at concentrations that do not affect signaling, physiology, or behavior of wild-type controls, statins reverse the signaling, electrophysiological, attention, and spatial learning deficits of Nf1^+/− mice. Prompted by these findings, clinical studies are currently underway to test the efficacy of statins as a treatment for the behavioral and cognitive deficits in individuals with NF1.

Similar to individuals with NF1, Nf1 mutant mice also show attention deficits. These deficits are thought to be key contributors to academic and social problems in children with NF1. Using an additional Nf1 GEM strain to study attention, in which the Nf1^+/− mutation is combined with Cre-driven homozygous Nf1 gene deletion in GFAP-expressing cells (Nf1 OPG mouse), it was found that reduced striatal dopamine was responsible for the observed attention deficits. Treatment with methylphenidate (but not with drugs that affect RAS) reversed the attention deficits of these Nf1 OPG mutants, suggesting that defects in brain catecholamine homeostasis contribute to the attention deficits observed. These results suggest that, in addition to drugs that affect RAS/ERK signaling, drugs that manipulate dopaminergic function could also be used to treat the cognitive deficits associated with NF1.

Treatments and future directions

With the availability of genetically engineered mouse models for NF1-associated CNS pathology, it now becomes possible to envision a pipeline in which fundamental basic science discoveries lead to the identification of new cellular and molecular targets for therapeutic drug design, culminating in preclinical evaluation before testing in patients with NF1. First, the success of Nf1 mouse model implementation has already resulted in the clinical evaluation of lovastatin in children with NF1-associated learning deficits and rapamycin analogs for the treatment of glioma. Second, mouse models afford an opportunity to envision specific features of NF1 as distinct diseases defined by the timing of NF1 gene inactivation or the particular cell of origin. Similar to other cancers, the identification of molecular or cellular subtypes of NF1-associated nervous system tumors or learning/behavioral problems may result in more individualized treatments with a higher likelihood of success. Third, as we further exploit these powerful preclinical models, additional cellular and molecular targets may emerge as candidates for future therapeutic drug design. In this regard, one could envision more effective therapies resulting from the combined use of targeted inhibition of multiple growth control pathways regulated by neurofibromin in the neoplastic cell (NF1-deficient neuroglial precursor) or dual targeting of non-neoplastic (microglia) and neoplastic cells within NF1-associated CNS tumors.

RASopathies & Autism

Autism traits in the RASopathies

Higher prevalence and severity of autism traits in RASopathies compared to unaffected siblings suggests that dysregulation of Ras/MAPK signalling during development may be implicated in ASD risk. Evidence for sex bias and potential sibling correlation suggests that autism traits in the RASopathies share characteristics with autism traits in the general population and clinical ASD population and can shed light on idiopathic ASDs.

This systematic study offers empirical support that autism traits are associated with developmental Ras/MAPK pathway dysregulation. It suggests that individuals affected by RASopathies should be evaluated for social communication challenges and offered treatment in these areas. This is the first strong evidence that multiple members of a well-defined biochemical pathway can contribute to autism traits. Future studies could explore potential modifying or epistatic factors contributing to variation within the RASopathies and the role of Ras/MAPK activation in idiopathic ASDs.

RAS/ERK Inhibitors

Inhibition of Ras for cancer treatment: the search continues

Discussion

Despite intensive effort, to date no effective anti-Ras strategies have successfully made it to the clinic. We present an overview of past and ongoing strategies to inhibit oncogenic Ras in cancer.

Conclusions

Since approaches to directly target mutant Ras have not been successful, most efforts have focused on indirect approaches to block Ras membrane association or downstream effector signaling. While inhibitors of effector signaling are currently under clinical evaluation, genome-wide unbiased genetic screens have identified novel directions for future anti-Ras drug discovery.

Conclusion

In some people with “autism” statins are an effective therapy.  Higher doses of statin are associated with side effects.  By knowing the principal mode of action of statins in autism, we might be able to develop a more potent therapy – STATIN PLUS.

On the basis of today’s post, investigating Farnesyltransferase inhibitors, as inhibitors of RAS signalling, looks an interesting option.

Gingerol is available as an inexpensive, supposedly standardized, product.  Ginger itself has been safely used in traditional medicine for thousands of years.

Perhaps Gingerol is the PLUS and for people unwilling to use a statin, perhaps Gingerol could be the statin?

The current medical view on ginger:-

According to the America Cancer Society

Recent preliminary results in animals show some effect in slowing or preventing tumor growth. While these results are not well understood, they deserve further study. Still, it is too early in the research process to say whether ginger will have the same effect in humans.

Anti-Oxidative and Anti-Inflammatory Effects of Ginger in Health and Physical Activity: Review of Current Evidence

  

Note on Intellectual Disability / MR

Regular readers may recall, I have commented that not only are many types of autism partially treatable, but so should be some types of Intellectual Disability / MR.  This same theme about treating cognitive dysfunction is raised in the paper below.

In the days when most readers of this blog were at school, 30-50% of people with an autism diagnosis were also diagnosed with Intellectual Disability / MR.  This is no longer the case; as autism diagnoses have skyrocketed in Western countries, diagnosis of Intellectual Disability / MR has not followed it.

People born today with what used to be called autism, often suffer from epilepsy and impaired cognitive function.  They do now tend to get rather sidelined by the much wider scope of the “autism” diagnosis used today, mainly in Anglo-Saxon countries (where most research is carried out).

The point where this matters is in clinical trials, since many of the milder autisms (now even being called “quirky autism”) may be caused by entirely different dysfunctions.  The observational diagnosis of “autism” is enough to enter most trials, but as we have seen in this blog, autism is not a true diagnosis; it is merely a description of symptoms.  It is like going to the doctor and saying “I think I might have a head ache” and after some questions, the doctors sits back and says “yes, you have a headache”.  You want to know why you have a head ache and how to make it go away.

Understanding Intellectual Disability through RASopathies

A fraction of the cases of intellectual disability is caused by point mutations or deletions in genes that encode for proteins of the RAS/MAP Kinase signaling pathway known as RASopathies. Here we examined the current understanding of the molecular mechanisms involved in this group of

genetic disorders focusing in studies which provide evidence that intellectual disability is potentially treatable and curable. The evidence presented supports the idea that with the appropriate understanding of the molecular mechanisms involved, intellectual disability could be treated pharmacologically and perhaps through specific mechanistic-based teaching strategies.