A virus as a trigger for some Cancer, most Multiple Sclerosis (MS) and perhaps some Autism

 

Mexico is the world's largest exporter of beer, and it's not just Corona

Not many years ago you would have been considered mad to suggest that a virus could trigger cancer, MS or some autism.

We now have a vaccine to prevent cancers triggered by the human papillomavirus (HPV). Young people aged 9 - 26 are offered this vaccine in many wealthy countries.

It is believed that the Epstein-Barr virus (EBV) contributes to about 1.5% of all cases of human cancer.

 

Epstein-Barr Virus and Cancer

 

EBV causes mononucleosis (IM, mono), also known as glandular fever. A commercial vaccine does not yet exist but is thought to be achievable.

Multiple sclerosis (MS) has long been thought to have a viral trigger. I have been reading about impaired myelination for 10 years and it takes a very long time for ideas to get confirmed.  In the case of MS it is again the Epstein-Barr virus. Almost all adults have been exposed to this virus and most people do not develop MS.  The science suggests that multiple events are needed to trigger MS, but that a required one is the presence of this virus.  That would suggest that if children were vaccinated against EBV, they could not go on to develop MS later in life.

 

Epstein-Barr virus may be leading cause of multiple sclerosis

 “The hypothesis that EBV causes MS has been investigated by our group and others for several years, but this is the first study providing compelling evidence of causality,” said Alberto Ascherio, professor of epidemiology and nutrition at Harvard Chan School and senior author of the study. “This is a big step because it suggests that most MS cases could be prevented by stopping EBV infection, and that targeting EBV could lead to the discovery of a cure for MS.”

 

Recall that MS is one of those diseases that is very much more prevalent in females than men.  It is the opposite of autism.

The science is moving on and now has got the point of explaining why EBV can cause cancer.  The actual biological pathways have been proposed.

 

Signaling pathways of EBV-induced oncogenesis

 

One of several examples is EBV-induced oncogenesis through the PI3K/AKT signaling pathway.

 

 

EBV-induced oncogenesis through the PI3K/AKT signaling pathway. LMP1 and LMP2A promote angiogenesis through the PI3K/AKT/HIF-1α/CCL5 signaling axis and the PI3K/AKT/mTOR/HIF-1α signaling axis, respectively. LMP1 inhibits PTEN through miRNA-21 and enhances the PI3K/AKT signaling pathway to promote the formation and proliferation of CSCs. EBV-miRNA-BART7-3P can also promote the high expression of β-catenin by inhibiting PTEN, leading to EMT

 

Regular readers may notice overlaps with what we have seen in autism. The same pathway can lead to autism.

Here is a recent autism paper on this same pathway.

Targeting PI3K-AKT/mTOR signaling in the prevention of autism

 The role of viruses in autism

Now we have established that medicine accepts that a virus can play a role in triggering cancer and that science points a finger at a virus being a trigger for MS, it is not so crazy to think about the role viruses might play in some autism. 

 

The easy part – Maternal Immune Activation (MIA)

We have clear evidence that if a pregnant mother’s immune system is activated during pregnancy the incidence of autism rises.  In this case it is the immune response that causes the problem, rather than the specific virus.

 

Virus specific

One very damaging virus, spread by mosquitos, is Zika. If a mother is infected  during pregnancy it may lead to microcephaly (small head), brain damage and joint/muscle malformation in her child.

 

Endogenous retroviruses

It has been suggested in the research for many years that endogenous retroviruses play a role in autism.

Human endogenous retroviruses (HERVs) are DNA sequences within human chromosomes; they comprise 1 to 8% of the human genome.  HERVs represent footprints of previous retroviral infection and have been termed “fossil viruses”.

 

Demystified . . . Human endogenous retroviruses

Human endogenous retroviruses (HERVs) are a family of viruses within our genome with similarities to present day exogenous retroviruses. HERVs have been inherited by successive generations and it is possible that some have conferred biological benefits. However, several HERVs have been implicated in certain cancers and autoimmune diseases. This article demystifies these retroviruses by providing an insight into HERVs, their means of classification, and a synopsis of HERVs implicated in cancer and autoimmunity. Furthermore, the biological roles of HERVs are explored.

Take home messages

o   Human endogenous retroviruses (HERVs) make up part of our genome and represent footprints of previous retroviral infection

o   HERVs possess a similar genomic organisation (gag–pol–env) to present day exogenous retroviruses but are not infectious

o   The HERV-K superfamily represents one of the most active HERVs and is capable of producing retroviral particles

o   HERVs may be of benefit to the host but could also be harmful, and may be involved in certain autoimmune diseases and cancers

 

I came across this article recently: 

Could an Ancient Virus Be a Genetic Driver of Autism?

Genome and transcriptome analysis revealed BTBR autism mouse models have increased levels of endogenous retrovirus genes. BTBR/R models of ASD showed differences in the expression of a variety of genes that are indicative of endogenous retrovirus activation. BTBR/R mice exhibit autistic-like behaviors without reduced learning abilities. 

Overall, the study revealed that retrovirus activation causes the copy number variants in BTBR mice to increase, which leads to the differences in behavior and brain structure seen in BTBR/J and BTBR/R mice. 

Further Developments 

BTBR/J mice are widely used by researchers as a mouse model of autism. However, the results of this study highlight the usefulness of the other lineage of BTBR/R mice because they exhibit autistic-like behavior without compromised spatial learning ability. The results also suggest that it may be possible to develop new treatments for autism that suppress ERV activation. 

Furthermore, it is necessary to classify autism subtypes according to their onset mechanism, which is a vital first step towards opening up new avenues of treatment for autism.

 

Here is the full paper, which comes from the RIKEN Brain Science Institute in Japan, which has been mentioned in a previous post.

 

An old model with new insights: endogenous retroviruses drive the evolvement toward ASD susceptibility and hijack transcription machinery during development

The BTBR T+Itpr3tf/J (BTBR/J) strain is one of the most valid models of idiopathic autism, serving as a potent forward genetics tool to dissect the complexity of autism. We found that a sister strain with an intact corpus callosum, BTBR TF/ArtRbrc (BTBR/R), showed more prominent autism core symptoms but moderate ultrasonic communication/normal hippocampus-dependent memory, which may mimic autism in the high functioning spectrum. Intriguingly, disturbed epigenetic silencing mechanism leads to hyperactive endogenous retrovirus (ERV), a mobile genetic element of ancient retroviral infection, which increases de novo copy number variation (CNV) formation in the two BTBR strains. This feature makes the BTBR strain a still evolving multiple-loci model toward higher ASD susceptibility. Furthermore, active ERV, analogous to virus infection, evades the integrated stress response (ISR) of host defense and hijacks the transcriptional machinery during embryonic development in the BTBR strains. These results suggest dual roles of ERV in the pathogenesis of ASD, driving host genome evolution at a long-term scale and managing cellular pathways in response to viral infection, which has immediate effects on embryonic development. The wild-type Draxin expression in BTBR/R also makes this substrain a more precise model to investigate the core etiology of autism without the interference of impaired forebrain bundles as in BTBR/J.

 

Hyper-activation of ancient retroviral infection accelerates host genome evolution toward ASD susceptibility by increasing the chance of CNV formation. The accumulated genetic variations lead to the divergence of autistic-like behaviors in both BTBR strains. Active ERV also recapitulates the viral infection process of ISR pathway invasion and IRES-mediated translation, which changes the global transcriptome during embryonic development in BTBR mice. BTBR/R has severer core symptoms of autism and wildtype Draxin expression, which suggests BTBR/R is a valid autism model with unaffected forebrain bundles.

 

There have been previous studies looking into ERVs and autism.

 

Children With Autism Spectrum Disorder and Their Mothers Share Abnormal Expression of Selected Endogenous Retroviruses Families and Cytokines

 

Human Endogenous Retroviruses in Autism Spectrum Disorders: Recent Advances and New Perspectives at the Gene-Environment Interface

Human endogenous retroviruses (HERVs) are genetic elements, derived from their exogenous retroviral counterpart by a process of germline infection and proliferation within the human genome, and their integration as proviruses led to the fixation and the vertical transmission, following Mendelian laws. HERVs currently make up ~8% of the genetic material, and some of them have been cooped for physiological functions. Otherwise, their activation in response to environmental factors has been associated with human pathological conditions. In the setting of neurodevelopmental disorders, HERVs have been proposed as contributing factors involved in Autism Spectrum Disorders (ASD), spanning the bridge between genetic susceptibility, environmental risk factors and immune response. We described a distinct expression profile of some HERV families and cytokines in lymphocytes from autistic children and in their mothers suggesting a close mother-child association in ASD. Moreover, in vitro treatment with an antiretroviral drug was able to restore the expression level of HERVs and cytokines providing new insights into the potential role of HERVs as biomarkers of ASD and raising the possibility of using HERVs expression as a therapeutic target for a tailored approach to patient care.

  

Conclusion 

We know that some cancer is preventable via a vaccine blocking the progress of a virus, hopefully more types of cancer will be prevented in future.

Some of the suggested modes of action for the Epstein-Barr virus (EBV) to cause cancer do involve pathways that are very relevant to autism.

It appears that an effective EBV vaccine might protect women (and some men) from developing multiple sclerosis (MS).  Will it also have the effect of reducing their chance of giving birth to a child with autism?  Time will tell.

Any kind of illness, viral or other, may trigger an exaggerated immune response during pregnancy and increase the incidence of autism.  This is the basis of one of the common animal models of autism, called Maternal Immune Activation (MIA).

The human endogenous retroviruses  (ERVs) accumulated as junk in our DNA do appear to be able to affect gene expression leading to cancer, autoimmune disease and indeed some autism.

The Japanese researchers from RIKEN suggest that it may be possible to develop new treatments for autism that suppress ERV activation.

One logical question is whether viruses are relevant just to causing autism or its ongoing level of severity.

In the case of cancer and MS it looks like the virus is primarily involved in triggering the disease.  Once the process has started, the benefit from suppressing the virus may have passed. 

Can existing antiviral drugs treat some autism?  Antiviral drugs work just for specific viruses and they just suppress them, rather than eliminating them.

The antiviral drug Valtrex has long been used by some doctors to treat autism in the US. Just Google it and you will find enthusiasts like parent Jenny McCarthy -- “when we started him on Valtrex, speech started pouring out of him”.  There have been no clinical trials.

This is an area where more research genuinely is needed. Hopefully the RIKEN Brain Science Institute will translate their ERV findings into approved therapies.  That is what is supposed to happen, but usually does not when it comes to autism.

Autism is nowadays such a broadly defined diagnosis, just about anything might have caused it. Autistic behaviors have been caused by a bacterium, a fungus/mold and very possibly a virus.  If only it was as straightforward as understanding and treating MS.

Another Potential Autism Therapy - novel compound E100 from Krakow, a combined histamine H3 receptor blocker (H3R antagonist) and an acetylcholine esterase inhibitor (AChEI)

 

Source:  Sukiennice and Main Square as seen from St. Mary's Basilica

Krakow’s old town is well worth a visit and is notable in Poland for not having been destroyed by the Germans, Russians or the US/UK during World War 2

 

Brain histamine and acetylcholine are implicated in cognitive disorders such as Alzheimer’s, schizophrenia, anxiety, and narcolepsy, all of which are found to be comorbid with autism.  This led a group in the United Arab Emirates (UAE) to test a new compound developed in Krakow, Poland, to see if this new Alzheimer’s compound is effective in two different models of autism. 

The Valproic Acid induced model of autism and the BTBR models were chosen.  The BTBR model is seen as a proxy for idiopathic autism; in this model there is no corpus callosum, which joins the left are right sides of the brain (red part in the graphic below). In an earlier post we looked at agenesis of the corpus callosum, which can be full or partial and is a feature of many types of disabling autism.

 

Source: https://en.wikipedia.org/wiki/Corpus_callosum#/media/File:Corpus_callosum.gif

  

The results of the mouse research were positive and it was concluded that E-100 is a potential drug candidate for future therapeutic management of autistic-like behaviours.

  

Simultaneous Blockade of Histamine H₃ Receptors and Inhibition of Acetylcholine Esterase Alleviate Autistic-Like Behaviors in BTBR T+ tf/J Mouse Model of Autism

Autism spectrum disorder (ASD) is a heterogenous neurodevelopmental disorder defined by persistent deficits in social interaction and the presence of patterns of repetitive and restricted behaviors. The central neurotransmitters histamine (HA) and acetylcholine (ACh) play pleiotropic roles in physiological brain functions that include the maintenance of wakefulness, depression, schizophrenia, epilepsy, anxiety and narcolepsy, all of which are found to be comorbid with ASD. Therefore, the palliative effects of subchronic systemic treatment using the multiple-active test compound E100 with high H₃R antagonist affinity and AChE inhibitory effect on ASD-like behaviors in male BTBR T+tf/J (BTBR) mice as an idiopathic ASD model were assessed. E100 (5, 10 and 15 mg/kg, i.p.) dose-dependently palliated social deficits of BTBR mice and significantly alleviated the repetitive/compulsive behaviors of tested animals. Moreover, E100 modulated disturbed anxiety levels, but failed to modulate hyperactivity parameters, whereas the reference AChE inhibitor donepezil (DOZ, one milligram per kilogram) significantly obliterated the increased hyperactivity measures of tested mice. Furthermore, E100 mitigated the increased levels of AChE activity in BTBR mice with observed effects comparable to that of DOZ and significantly reduced the number of activated microglial cells compared to the saline-treated BTBR mice. In addition, the E100-provided effects on ASD-like parameters, AChE activity, and activated microglial cells were entirely reversed by co-administration of the H₃R agonist (R)-α-methylhistamine (RAM). These initial overall results observed in an idiopathic ASD mice model show that E100 (5 mg/kg) alleviated the assessed behavioral deficits and demonstrate that simultaneous targeting of brain histaminergic and cholinergic neurotransmissions is crucial for palliation of ASD-like features, albeit further in vivo assessments on its effects on brain levels of ACh as well as HA are still needed. 

The observed results in an idiopathic ASD mice model comprehend our previously obtained palliative effects of E100 in VPA-induced ASD in mice. Also, the current observations demonstrate that simultaneous targeting of the CNS histaminergic and cholinergic neurotransmissions is crucial for palliation of several ASD-like features, namely ASD-like social deficits and repetitive/compulsive behaviors and mitigated the levels of cerebellar microglial cells and AChE activity of tested BTBR mice used as idiopathic ASD model. Whether the alleviation of autistic-like behaviors in BTBR mice is obtained after administration of H₃R antagonist or co-administration of an H₃R antagonist and an AChEI was beyond the scope of this project and will require dose-finding experiments for several ratios of the combination of AChEIs and H₃R antagonist. Further in vivo assessments on brain levels of ACh as well as HA in BTBR mice following different systemic treatments of test compound as well as reference drugs including a standard H₃R antagonist (e.g., pitolisant) are still needed to evaluate whether multiple-active compounds, e.g., E100, is superior to AChEIs or H₃R antagonists when administered alone.

The design and synthesis of E100, namely 1-(7-(4-chlorophenoxy)heptyl)azepane, was carried out in the Department of Technology and Biotechnology of Drugs, Jagiellonian University Medical College, Krakow, Poland and as described in in previous reports.

  

The Dual-Active Histamine H₃ Receptor Antagonist and Acetylcholine Esterase Inhibitor E100 Alleviates Autistic-Like Behaviors and Oxidative Stress in Valproic Acid Induced Autism in Mice

The histamine H3 receptor (H3R) functions as auto- and hetero-receptors, regulating the release of brain histamine (HA) and acetylcholine (ACh), respectively. The enzyme acetylcholine esterase (AChE) is involved in the metabolism of brain ACh. Both brain HA and ACh are implicated in several cognitive disorders like Alzheimer’s disease, schizophrenia, anxiety, and narcolepsy, all of which are comorbid with autistic spectrum disorder (ASD). Therefore, the novel dual-active ligand E100 with high H3R antagonist affinity (hH3R: K_i = 203 nM) and balanced AChE inhibitory effect (EeAChE: IC₅₀ = 2 µM and EqBuChE: IC₅₀ = 2 µM) was investigated on autistic-like sociability, repetitive/compulsive behaviour, anxiety, and oxidative stress in male C57BL/6 mice model of ASD induced by prenatal exposure to valproic acid (VPA, 500 mg/kg, intraperitoneal (i.p.)). Subchronic systemic administration with E100 (5, 10, and 15 mg/kg, i.p.) significantly and dose-dependently attenuated sociability deficits of autistic (VPA) mice in three-chamber behaviour (TCB) test (all p < 0.05). Moreover, E100 significantly improved repetitive and compulsive behaviors by reducing the increased percentage of marbles buried in marble-burying behaviour (MBB) (all p < 0.05). Furthermore, pre-treatment with E100 (10 and 15 mg/kg, i.p.) corrected decreased anxiety levels (p < 0.05), however, failed to restore hyperactivity observed in elevated plus maze (EPM) test. In addition, E100 (10 mg/kg, i.p.) mitigated oxidative stress status by increasing the levels of decreased glutathione (GSH), superoxide dismutase (SOD), and catalase (CAT), and decreasing the elevated levels of malondialdehyde (MDA) in the cerebellar tissues (all p < 0.05). Additionally, E100 (10 mg/kg, i.p.) significantly reduced the elevated levels of AChE activity in VPA mice (p < 0.05). These results demonstrate the promising effects of E100 on in-vivo VPA-induced ASD-like features in mice, and provide evidence that a potent dual-active H3R antagonist and AChE inhibitor (AChEI) is a potential drug candidate for future therapeutic management of autistic-like behaviours.

 

Acetylcholinesterase inhibitor (AChEI)

An acetylcholinesterase inhibitor (AChEI) inhibits the enzyme acetylcholinesterase from breaking down the neurotransmitter acetylcholine, thereby increasing both its level and duration of action.

We know that a surge in acetylcholine improves learning.

Examples of acetylcholinesterase inhibitors include: -

·        Alzheimer’s drugs Donepezil and Galantamine (both used off-label in autism)

·        Caffeine

·        Rosmarinic acid

  

Histamine H3 antagonists

Histamine H3 antagonists bind to H3 receptors in the brain so that histamine cannot activate them, examples include: -

Betahistine

Betahistine/Ciproxifan produces wakefulness and attentiveness in animal studies, and produced cognitive enhancing effects without prominent stimulant effects at relatively low levels of receptor occupancy, and pronounced wakefulness at higher doses. It has therefore been proposed as a potential treatment for sleep disorders such as narcolepsy and to improve vigilance in old age, particularly in the treatment of conditions such as Alzheimer's disease 

Pitolisant 

Pitolisant/ Wakix, is a medication for the treatment of excessive daytime sleepiness (EDS) in adults with narcolepsy. It is a histamine 3 (H₃) receptor antagonist/inverse agonist. It represents the first commercially available medication in its class. Pitolisant enhances the activity of histaminergic neurons in the brain that function to improve a person's wakefulness.

The most common side effects include difficulty sleeping, nausea, and feeling worried

  

There is a lot in this blog about histamine, mainly in relation to mast cells and allergic responses. You do have mast cells in your brain. Science has not fully established the role of histamine in humans, particularly in the brain. 

A quick recap on histamine:- 

H1 receptor

The H1 receptor is what mediates things like pollen allergies, but it plays a role in the brain that affects sleep, appetite, body temperature and cognition.

 

H2 receptor

The H2 receptor in the gut is the target of acid lowering drugs. These receptors do exist in the brain, but nobody has figured out their function.

 

H3 receptor

The H3 receptor is mainly in the central nervous system where it regulates the release of brain histamine (HA) and acetylcholine (ACh); it also affects the release of serotonin and norepinephrine. Elsewhere in the body H3 receptors play a role in the release of gastric acids. 

H4 receptor

The H4 receptor is not well understood. It plays a role in mast cells, but its role in cognition, allergy and inflammation is not fully understood.

 

Histamine-gated Chloride Channels

It does not seem to have a cute name like H5, but there appears to be another target for histamine, that is a histamine gated chloride channel, which seems to be present in the brain 

 

Histamine is produced from the amino acid histidine.  Some food contains histamine.

Somewhat bizarrely, it seems that if you supplement the amino acid histidine you get an anti-allergy effect; it is like more histidine makes/releases less histamine.  One of nature’s feedback loops at work, I suppose.

Histamine is mainly stored in mast cells (the target of mast cell stabilizer drugs), some is stored in basophils. Within the brain histamine functions as a neurotransmitter and you have so-called histaminergic neurons.

Once released, histamine is supposed to be deactivated by the enzymes HNMT or DAO (histamine-N-methyltransferase or diamine oxidase).  If you lack HNMT or DAO you will have problems with histamine.

  

Is there a synergistic benefit from blocking the H3 receptors in the brain and increasing the level of acetylcholine? 

The researchers from the UAE seem to believe that the new Polish drug E-100 has the unique benefit of doing two clever things at once that together might be helpful in human autism, as well as in the original target, Alzheimer’s.

 

 

Conclusion 

I did write in length in this blog about histamine; there are 18 posts tagged with Histamine. 

https://epiphanyasd.blogspot.com/search/label/Histamine

This did take me to the world of mast cell stabilizers and then L-type calcium channel blockers, so it was productive; but there were clearly huge gaps in the science that still remain.

The interesting substances from my original investigation include: -

·        H1 anti-histamines that also stabilize mast cells (Azelastine, Rupatadine, Ketotifen).

·        Pure mast cell stabilizers like Cromolyn Sodium

·        L-type calcium channel blockers such as Verapamil

 

It seemed highly likely that H3 and H4 receptors might also be useful targets, let alone the even less understood histamine gated chloride channels.

Is the new Polish drug E-100 going to be effective in human autism? and in which people?  Are the people with mast cell problems likely to be among the responders?