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Wednesday, 3 October 2018

Ketones and Autism Part 6 - Capric Acid (C10) for Mitochondrial Disease, in Particular Complex 1, plus more on Metformin



Capric Acid (C10) is so named because it smells like a goat (Goat in Latin = Caper)
Photographer: Armin Kübelbeck, CC-BY-SA, Wikimedia Commons

Rather than Goaty acid, C10 is called Capric acid, or indeed Decanoic acid (after its 10 carbon atoms). Today’s post is indirectly again about ketones, because if you eat a Ketogenic Diet (KD) you are likely to consume a fair amount of Capric acid (C10).
I have written a lot in this blog about mitochondria, even though I do not think my son has mitochondrial dysfunction. Clearly many people with autism do have a lack of one or more of the critical mitochondrial enzyme complexes that allow glucose to be converted to ATP (usable energy), by the clever process OXPHOS (Oxidative phosphorylation).

The “rate limiting” enzyme is usually Complex 1, meaning that is the one it is most important not to be short of.
Another favourite, but obscure, subject of this blog is PPAR gamma.

Peroxisome proliferator-activated receptors (PPARs) are a group of proteins that function as transcription factors regulating the expression of certain genes. Transcription factors are particularly important because they trigger numerous effects.
PPAR gamma plays a key role in fat storage and glucose metabolism, but has other functions. 

Activation of PPAR-gamma by Capric acid (C10) has been shown to increase the number of mitochondria, increase the mitochondrial enzyme citrate synthase, increase complex I activity in mitochondria, and increase activity of the antioxidant enzyme catalase. 
So, if you have autism and impaired mitochondrial function, C10 may well give a benefit because it can increase the peak power available to your brain.


The Ketogenic diet (KD) is an effective treatment with regards to treating pharmaco-resistant epilepsy. However, there are difficulties around compliance and tolerability. Consequently, there is a need for refined/simpler formulations that could replicate the efficacy of the KD. One of the proposed hypotheses is that the KD increases cellular mitochondrial content which results in elevation of the seizure threshold. Here, we have focussed on the medium-chain triglyceride form of the diet and the observation that plasma octanoic acid (C8) and decanoic acid (C10) levels are elevated in patients on the medium-chain triglyceride KD. Using a neuronal cell line (SH-SY5Y), we demonstrated that 250-μM C10, but not C8, caused, over a 6-day period, a marked increase in the mitochondrial enzyme, citrate synthase along with complex I activity and catalase activity. Increased mitochondrial number was also indicated by electron microscopy. C10 is a reported peroxisome proliferator activator receptor γ agonist, and the use of a peroxisome proliferator activator receptor γ antagonist was shown to prevent the C10-mediated increase in mitochondrial content and catalase. C10 may mimic the mitochondrial proliferation associated with the KD and raises the possibility that formulations based on this fatty acid could replace a more complex diet. We propose that decanoic acid (C10) results in increased mitochondrial number. Our data suggest that this may occur via the activation of the PPARγ receptor and its target genes involved in mitochondrial biogenesis. This finding could be of significant benefit to epilepsy patients who are currently on a strict ketogenic diet. Evidence that C10 on its own can modulate mitochondrial number raises the possibility that a simplified and less stringent C10-based diet could be developed.

Capric Acid (C10) as a PPARγ agonist

As shown in the above study the mechanism by which C10 benefits the mitochondria is via PPARγ agonism.

Here is another study confirming that C10 is indeed a PPARγ agonist.


Background: Mechanism of action of medium chain fatty acid remains unknown.

Results: Our results show that decanoic acid (C10) binds and activates PPARγ.

Conclusion: Decanoic acid acts as a modulator of PPARγ and reduces blood glucose levels with no weight gain.

Significance: This study could lead to design of better type 2 diabetes drugs.


Other PPARγ agonists
PPARγ agonists have been covered previously in this blog and we know that glitazones, a class of drugs for diabetes, do improve some types of autism. Glitazones are PPARγ agonists.

Metformin, a very widely used drug for type 2 diabetes, works differently to Glitazones, but I did suggest a while back it should help some types of autism. Last year it was indeed found to be beneficial in Fragile X.


 "Basically, it's something like a wonder drug," Sonenberg said.
The study suggests that metformin might also be used to treat other autism spectrum disorders, said Ilse Gantois, a research associate in Sonenberg's lab at McGill.
"We mostly looked at the autistic form of behaviour in the Fragile X mouse model," explained Gantois, who is co-lead author with McGill researchers Arkady Khoutorsky and Jelena Popic. "We want to start testing other mouse models to see if the drug could also have benefits for other types of autism."

Metformin is very cheap and has been used in humans for 60 years. It is another example of re-purposing a drug from Grandpa’s medicine cabinet to treat Grandson’s autism. 

Metformin has been trialled to combat obesity in idiopathic autism caused by antipsychotics. It did help with weight gain, but no comments were made about behavioural improvements, but then those studied were on antipsychotic drugs, which might mask such effects. 
Glitazone-type drugs appear more problematic than Metformin.

There are natural PPAR gamma agonists and they are often used to lower cholesterol, lower blood sugar and improve insulin sensitivity.
Sytrinol, a product containing flavanols tangeretin and nobiletin does indeed have a positive effect on some people’s autism, but for most people (but not all) the effect is lost after a few days.

Our doctor reader Maja, did suggest combining it with a PPARα agonist to see if the effect might be maintained.
This combination has indeed been researched for type 2 diabetes.               

The effect of dual PPAR alpha/gamma stimulation with combination of rosiglitazone and fenofibrate on metabolic parameters in type 2 diabetic patients.


There actually is another natural substance that is an agonist of both PPARγ and PPARα, Berberine, the alkaloid long used in Chinese medicine.
In the research it is suggested that BRB localizes in mitochondria, inhibits respiratory electron chain and activates AMPK”, which is not what you would want. But this may not be correct.

People who like supplements might want to follow up on Berberine.
Berberine is used by many people with diabetes and a few with autism, for all kinds of reasons, from mercury to GI problems.

Berberine is a potent agonist of peroxisome proliferator activated receptor alpha.


Although berberine has hypolipidemic effects with a high affinity to nuclear proteins, the underlying molecular mechanism for this effect remains unclear. Here, we determine whether berberine is an agonist of peroxisome proliferator-activated receptor alpha (PPARalpha), with a lipid-lowering effect. The cell-based reporter gene analysis showed that berberine selectively activates PPARalpha (EC50 =0.58 mM, Emax =102.4). The radioligand binding assay shows that berberine binds directly to the ligand-binding domain of PPARalpha (Ki=0.73 mM) with similar affinity to fenofibrate. The mRNA and protein levels of CPT-Ialpha gene from HepG2 cells and hyperlipidemic rat liver are remarkably up-regulated by berberine, and this effect can be blocked by MK886, a non-competitive antagonist of PPARalpha. A comparison assay in which berberine and fenofibrate were used to treat hyperlipidaemic rats for three months shows that these drugs produce similar lipid-lowering effects, except that berberine increases high-density lipoprotein cholesterol more effectively than fenofibrate. These findings provide the first evidence that berberine is a potent agonist of PPARalpha and seems to be superior to fenofibrate for treating hyperlipidemia.


                                                                                                                                     

Sources of Capric Acid (C10)
Goat milk is a good source of capric acid.
Capric acid is 8-10% of coconut oil and 4% of palm kernel oil

Capric acid is a large component (about 40%) of the less expensive MCT oil supplements.


1.2. Fatty acid composition in goat milk fat Average goat milk fat differs in contents of its fatty acids significantly from average cow milk fat, being much higher in butyric (C4:0), caproic (C6:0), caprylic (C8:0), capric (C10:0), lauric (C12:0), myristic (C14:0), palmitic (C16:0), linoleic (C18:2), but lower in stearic (C18:0), and oleic acid (C18:1) (Table 1). Three of the medium chain fatty acids (caproic, caprylic, and capric) have actually been named after goats, due to their predominance in goat milk. They contribute to 15% of the total fatty acid content in goat milk in comparison to 5% in cow milk (Haenlein, 1993). The presence of relatively high levels of medium chain fatty acids (C6:0 to C10:0) in goat milk fat could be responsible for its inferior flavour (Skjevdal, 1979). 

             
Conclusion
If someone responds well to coconut oil or cheaper MCT oil the reason may have more to do with PPAR gamma and improved mitochondrial function than anything to do with ketones and what they do.
Cheaper MCT oils are mainly a mixture of C8 and C10. To maximize the production of the ketone BHB you really want just C8, but if what you really need is a PPAR gamma agonist, to perk up your mitochondria, it is the C10 you need.
You may indeed benefit from both ketones and agonizing PPAR gamma, in which case you either follow the Ketogenic Diet, or supplement BHB, C8 and C10.
I think this explains why some people with autism reportedly respond well to teaspoon-sized doses of cheaper MCT oil or small amounts of coconut oil.
If you have Complex 1 mitochondrial dysfunction then a dose of Capric acid (C10) is likely to help.
Berberine may, or may not be, as effective as C10. I doubt we will ever know. I think C10 is the better option. 
I wonder when the Canadian researchers will publish their results showing whether Metformin is beneficial beyond Fragile X syndrome. They do not really know why it helps, but that is a repeating theme in medicine.  It is a cheap safe drug, so it would be a pity to waste time finding out if it could be repurposed for some autism.



Wednesday, 26 September 2018

Back to School and Try to be Cool


The Milaneses and their shops
                                             
Another school year has begun, which is always a good time for Monty, with ASD now aged 15. He loves his small international school; he has been there since was 3 years old. School is fun because he gets lots of attention and stimulation. Other children are surprisingly nice to him and the teachers get to meet someone with autism.

In kindergarten and the early years of primary/junior school boys with autism often get taken care of by some of the nicer girls. It is like having a live human doll to mother. It is amazing how this pattern repeats among different children with autism. This gradually seems to fade away as girls discover that they need to be cool and kids with special needs tend not to be cool.

We had a visit over the summer from a Dutch girl who was one of these nice little girls when she was younger. Now she is also 15 and has not seen Monty for a few years. The difference between them now is much starker than 10 years ago, but there still is a bond.
Last year at school for friendship development day they had to climb a small mountain, this year they went bowling. The girls in the year above wanted to teach Monty how to bowl and they did. The year above is unusual in being mainly girls.
I know that most children with autism/Asperger's cope with junior school but many, particularly Aspies, really hate high school, because they do not fit in and so they get bullied. Monty has never experienced any such problems, but he is not an Aspie, so he is not a target.  People who are a tiny bit different get bullied, people who are more different tend not to get picked on.
Big brother has graduated from high school and gone to University in Milan, Italy, far away. In his time at school the class were not so nice to the Aspie boy they had in their group and he was not nice to them. I think it was a lost opportunity; ultimately it is up to parents to make things happen.  Parents often blame schools, but most schools have no expert knowledge and have many other issues to deal with. Much more could be done to integrate those who are just a tiny bit different.
I think that to fit in, the special needs pupil needs to be “cool” and have an assistant who is seen by the class as “cool”. What counts as cool? How you dress, sport you do, musical skills etc. For the assistant it includes how old you behave; having an Assistant who behaves like a 50-year-old, is not going to help integrate a teenager.
Most kids figure out what is cool, but if you have any degree of autism you may not. I think some people would indeed benefit from “cool lessons”, you could call it “how to be a teenager”. There are workshops for Aspie teenagers, a little bit like this. 
In our household this new school year is much more about big brother. We have lots of video calls about Italian bureaucracy, how to cook, how expensive going out is, but how cheap Italian coffee is (no Starbucks).  Overall Milan is beautiful city, full of very fashion-conscious people who do seem to enjoy life.  The Italian students in class can be identified by their expensive sunglasses and their going for “aperitivo”.  The foreign boys are going for birra, bier, pivo, bira or cerveza, which is cheap in a supermarket but very expensive elsewhere. 
Bocconi is Italy’s top University for economics; it seems pretty well organized and is very inclusive. They have many students from poorer countries, who get substantial financial support from the University, which is the opposite of what happens in England (where foreign students face paying up to 3 times more for tuition). Germany is also good in this regard, where even Medical School is free to all, but you do need to learn German. Big brother is getting to practise his foreign languages, but tuition is in English.


   

Wednesday, 19 September 2018

Ketones and Autism Part 5 - BHB, Histone Acetylation Modification, BDNF Expression, PKA, PKB/Akt, Microglial Ramification, Depression and Kabuki Syndrome















Child displaying elongated eyelids typical of Kabuki syndrome
Source: Given by Parents of children pictured with purpose of representing children with kabuki on Wikipedia. 

The syndrome is named after its resemblance to Japanese Kabuki makeup.

As we have discovered in this blog, autism is just a condition where certain genes are over-expressed and other genes are under-expressed. Put like that makes it sound quite simple.

Methylation of histones can either increase or decrease transcription of genes. The subject is highly complex, but we can keep things simple.

The child in the photo above has Kabuki syndrome and is likely to exhibit features of autism.  In most cases this is the result of a lack of expression of the KMT2D/MLL2 gene which encodes a protein called Histone-lysine N-methyltransferase.  Unfortunately, this is quite an important protein, because it promotes the “opening of chromatin”.  It adds a “trimethylation mark to H3K4”, just think of it as a pink post-it on your DNA. 
We get H3K4me3, which is an epigenetic marker (me3, because it is trimethylation). H3K4me3 promotes gene activation and it can cause a relative imbalance between open and closed chromatin states for critical genes. It has been suggested that it may be possible to restore this balance with drugs that promote open chromatin states, such as histone deacetylase inhibitors (HDACi).
What all this means is that people with Kabuki start with under-expression of just one gene, but this leads to the miss-expression of numerous other genes. Because science has figured out what the KMT2D/MLL2 gene does, we can find ways of treating this syndrome.

BHB as an HDAC inhibitor and a treatment for Kabuki syndrome

HDAC inhibitors (HDACi) are also suggested as therapies for other single gene syndromes. We saw in an earlier post that in Pitt Hopkins syndrome people lack Transcription Factor 4 (TCF4). Too little TC4 is not good, but too much TC4 is one feature of schizophrenia.
We saw in the research that we can increase expression of TCF4 using a class 1 HDAC inhibitor and we can also activate the Wnt pathway, which can also be achieved by inhibiting GSK3 (all themes covered in this blog).
So, Pitt Hopkins therapies include: -
·        Wnt activation (covered extensively in this blog) this includes statins and GSK3 inhibitors like Lithium

·        HDAC inhibitors like valproic acid, some cancer drugs, sodium butyrate and indeed the ketone BHB
This also means that people with schizophrenia, and likely too much TCF4, might benefit from the opposite gene expression modification, so a Wnt inhibitor, these include some cheap, safe, drugs used to treat children with parasites (Mebendazole/ Niclosamide etc) and of course GSK3 activators.
It is interesting that after 500 posts of this amateur blog you can start to fit the science together and identify rational therapies for complex disorders and  note that these therapies have much wider application, either to milder conditions or discovering avenues to treat the opposite genetic variation.  The underlying biological themes are all reoccurring in different types of autism/schizophrenia/ bipolar and you do wonder why more has not been done by professionals to apply this knowledge. 500 posts may sound a lot, but for autism researchers this is their paid, full-time job, not just a hobby pastime.

But then again, Simon Baron-Cohen, Head of Cambridge University's Autism Research Centre, recently published an article in which he wrote:

"We at the Autism Research Centre have no desire to cure, prevent or eradicate autism ... As scientists, our agenda is simply to understand the causes of autism." 

Whose team is he playing for?

My conclusion is that perhaps Baron-Cohen has Asperger's himself, because he does not realize that a disorder, severe enough for a medical/psychiatric diagnosis, is a bad thing that should be minimized and ideally prevented, just like any other brain disorder. His cousin the actor Sacha gives a very good impression of someone with bipolar, so perhaps they both need a Wnt activator?

Would a mother with Multiple Sclerosis (MS) want her daughter to also develop MS to share the experience? I think not. If it is just "quirky autism", it does not warrant a medical diagnosis, because it is perfectly okay to be quirky. 

This blog does have many Aspie readers who do want pharmacological therapy and that is their choice; I am fully supportive of them and wish them well.

Back to Kabuki
There is more than one type of HDAC and so there are different types of HDACi.  There are actually 18 HDAC enzymes divided into four classes
The ketone BHB inhibits HDAC class I enzymes called HDAC2 and HDAC3
The good news is that the ketogenic diet, which produces BHB, does indeed show merit as a therapy for Kabuki.

Kabuki syndrome is caused by haploinsufficiency for either of two genes that promote the opening of chromatin. If an imbalance between open and closed chromatin is central to the pathogenesis of Kabuki syndrome, agents that promote chromatin opening might have therapeutic potential. We have characterized a mouse model of Kabuki syndrome with a heterozygous deletion in the gene encoding the lysine-specific methyltransferase 2D (Kmt2d), leading to impairment of methyltransferase function. In vitro reporter alleles demonstrated a reduction in histone 4 acetylation and histone 3 lysine 4 trimethylation (H3K4me3) activity in mouse embryonic fibroblasts from Kmt2d+/βGeo mice. These activities were normalized in response to AR-42, a histone deacetylase inhibitor. In vivo, deficiency of H3K4me3 in the dentate gyrus granule cell layer of Kmt2d+/βGeo mice correlated with reduced neurogenesis and hippocampal memory defects. These abnormalities improved upon postnatal treatment with AR-42. Our work suggests that a reversible deficiency in postnatal neurogenesis underlies intellectual disability in Kabuki syndrome.

Intellectual disability is a common clinical entity with few therapeutic options. Kabuki syndrome is a genetically determined cause of intellectual disability resulting from mutations in either of two components of the histone machinery, both of which play a role in chromatin opening. Previously, in a mouse model, we showed that agents that favor chromatin opening, such as the histone deacetylase inhibitors (HDACis), can rescue aspects of the phenotype. Here we demonstrate rescue of hippocampal memory defects and deficiency of adult neurogenesis in a mouse model of Kabuki syndrome by imposing a ketogenic diet, a strategy that raises the level of the ketone beta-hydroxybutyrate, an endogenous HDACi. This work suggests that dietary manipulation may be a feasible treatment for Kabuki syndrome.
 Although BHB has previously been shown to have HDACi activity (7, 21), the potential for therapeutic application remains speculative. Here, we show that therapeutically relevant levels of BHB are achieved with a KD modeled on protocols that are used and sustainable in humans (22, 23). In addition, we demonstrate a therapeutic rescue of disease markers in a genetic disorder by taking advantage of the BHB elevation that accompanies the KD.
Our findings that exogenous BHB treatment lead to similar effects on neurogenesis as the KD support the hypothesis that BHB contributes significantly to the therapeutic effect. In our previous study (6), the HDACi AR-42 led to improved performance in the probe trial of the MWM for both Kmt2d+/βGeo and Kmt2d+/+ mice (genotype-independent improvement). In contrast, KD treatment only led to improvement in Kmt2d+/βGeo mice (genotype-dependent improvement). This discrepancy may relate to the fact that AR-42 acts as an HDACi but also affects the expression of histone demethylases (24), resulting in increased potency but less specificity. Alternatively, because the levels of BHB appear to be higher in Kmt2d+/βGeo mice on the KD, the physiological levels of BHB might be unable to reach levels in Kmt2d+/+ mice high enough to make drastic changes on chromatin.
In addition to the effects seen on hippocampal function and morphology, we also uncovered a metabolic phenotype in Kmt2d+/βGeo mice, which leads to both increased BHB/AcAc and lactate/pyruvate ratios during ketosis; an increased NADH/NAD+ ratio could explain both observations. This increased NADH/NAD+ ratio may relate to a previously described propensity of Kmt2d+/βGeo mice toward biochemical processes predicted to produce NADH, including beta-oxidation, and a resistance to high-fat-diet–induced obesity (27). If this exaggerated BHB elevation holds true in patients with KS, the KD may be a particularly effective treatment strategy for this patient population; however, this remains to be demonstrated. Alterations of the NADH/NAD+ ratio could also affect chromatin structure through the action of sirtuins, a class of HDACs that are known to be NAD+ dependent (28). Advocates of individualized medicine have predicted therapeutic benefit of targeted dietary interventions, although currently there are few robust examples (2931). This work serves as a proof-of-principle that dietary manipulation may be a feasible strategy for KS and suggests a possible mechanism of action of the previously observed therapeutic benefits of the KD for intractable seizure disorder (22, 23).                   
Kabuki syndrome (KS) (Kabuki make-up syndrome, Niikawa-Kuroki syndrome) is a rare genetic disorder first diagnosed in 1981. Kabuki make-up syndrome (KMS) is a multiple malformation/intellectual disability syndrome that was first described in Japan but is now reported in many other ethnic groups. KMS is characterized by multiple congenital abnormalities: craniofacial, skeletal, and dermatoglyphic abnormalities; intellectual disability; and short stature. Other findings may include: congenital heart defects, genitourinary anomalies, cleft lip and/or palate, gastrointestinal anomalies including anal atresia, ptosis and strabismus, and widely spaced teeth and hypodontia. The KS is associated with mutations in the MLL2 gene in some cases were also observed deletions of KDM6A. This study describes three children with autism spectrum disorders (ASDs) and KS and rehabilitative intervention that must be implemented.

So what?
Unless you know someone with Kabuki syndrome, you might be wondering what does this matter to autism.
What is shows is that BHB/KD is sufficiently potent to be a viable HDAC inhibitor. 
We know that some cancer drug HDAC inhibitors are effective in some mouse models of autism. But these drugs usually have side effects. 

HDAC Inhibitors for which Cancer/Autism? 

BHB is safe endogenous substance, so it is a “natural” HDACi. 

The effect of HDAC2 and HDAC3 on BDNF 
Brain derived neurotropic factor (BDNF) is like brain fertilizer. In some types of autism, you would like more BDNF.
When you exercise you produce BHB and that goes on to trigger the release of BDNF. This process also involves NF-kB activation

Exercise induces beneficial responses in the brain, which is accompanied by an increase in BDNF, a trophic factor associated with cognitive improvement and the alleviation of depression and anxiety. However, the exact mechanisms whereby physical exercise produces an induction in brain Bdnf gene expression are not well understood. While pharmacological doses of HDAC inhibitors exert positive effects on Bdnf gene transcription, the inhibitors represent small molecules that do not occur in vivo. Here, we report that an endogenous molecule released after exercise is capable of inducing key promoters of the Mus musculus Bdnf gene. The metabolite β-hydroxybutyrate, which increases after prolonged exercise, induces the activities of Bdnf promoters, particularly promoter I, which is activity-dependent. We have discovered that the action of β-hydroxybutyrate is specifically upon HDAC2 and HDAC3, which act upon selective Bdnf promoters. Moreover, the effects upon hippocampal Bdnf expression were observed after direct ventricular application of β-hydroxybutyrate. Electrophysiological measurements indicate that β-hydroxybutyrate causes an increase in neurotransmitter release, which is dependent upon the TrkB receptor. These results reveal an endogenous mechanism to explain how physical exercise leads to the induction of BDNF.

Results: ROS was significantly increased in neurons after 6 hours of ketone incubation. However, after 24 hours, neurons show improved efficiency in ATP productions, upregulated expressions of antioxidant enzyme SOD2, and enhanced resistance to excitotoxicity. These effects were significantly abolished in neurons after treatment with TrkB inhibitor. More interestingly, ROS scavengers or blocking ROS-dependent NF-kB activation significantly decreased ketone-dependent BDNF-upregulation in neurons, suggesting that ROS may have increased BDNF expressions to improve mitochondrial respiration as adaptive responses.
Conclusions: 3OHB initially generates ROS and poses oxidative stress. However, ROS appears to trigger adaptive responses against oxidative stress by upregulating BDNF through NF-kB activation, which can improve mitochondrial oxidative capacity and ultimately enhance neuroprotection
BHB/KD promotes PKA/CREB activation 
Another clever way to change the function/expression of multiple genes in one single step is to use a protein kinase.  Up to 30% of all human proteins may be modified by kinase activity.  
A protein kinase is an enzyme that modifies other proteins by chemically adding phosphate groups to them (phosphorylation). Phosphorylation usually results in a functional change of the target protein.
In the autism research you may well have come across PKA, PKB (Akt) and PKC. They clearly are disturbed in much autism.
The research shows that BHB activates PKA.
If you want good myelination you need PKA.
This might be another reason why BHB/KD is helpful in people with Multiple Sclerosis.
In much autism the myelin coating is found to be abnormally thin. 

BHB, Microglial Ramification and Depression (yes, depression)
I am increasingly impressed by research from China. The paper below by Chao Huang et al is excellent and I think we need a Chinese on the Dean’s List of this blog, it looks like he is the first.
Nantong, China on the Yangtze River and home to Chao Huang and more than 7 million other people 
Source: Wikipedia Dolly 442

The ketone body metabolite β-hydroxybutyrate induces an antidepression-associated ramification of microglia via HDACs inhibition-triggered Akt-small RhoGTPase activation. 


Abstract


Direct induction of macrophage ramification has been shown to promote an alternative (M2) polarization, suggesting that the ramified morphology may determine the function of immune cells. The ketone body metabolite β-hydroxybutyrate (BHB) elevated in conditions including fasting and low-carbohydrate ketogenic diet (KD) can reduce neuroinflammation. However, how exactly BHB impacts microglia remains unclear. We report that BHB as well as its producing stimuli fasting and KD induced obvious ramifications of murine microglia in basal and inflammatory conditions in a reversible manner, and these ramifications were accompanied with microglial profile toward M2 polarization and phagocytosis. The protein kinase B (Akt)-small RhoGTPase axis was found to mediate the effect of BHB on microglial shape change, as (i) BHB activated the microglial small RhoGTPase (Rac1, Cdc42) and Akt; (ii) Akt and Rac1-Cdc42 inhibition abolished the pro-ramification effect of BHB; (iii) Akt inhibition prevented the activation of Rac1-Cdc42 induced by BHB treatment. Incubation of microglia with other classical histone deacetylases (HDACs) inhibitors, but not G protein-coupled receptor 109a (GPR109a) activators, also induced microglial ramification and Akt activation, suggesting that the BHB-induced ramification of microglia may be triggered by HDACs inhibition. Functionally, Akt inhibition was found to abrogate the effects of BHB on microglial polarization and phagocytosis. In neuroinflammatory models induced by lipopolysaccharide (LPS) or chronic unpredictable stress (CUS), BHB prevented the microglial process retraction and depressive-like behaviors, and these effects were abolished by Akt inhibition. Our findings for the first time showed that BHB exerts anti-inflammatory actions via promotion of microglial ramification. 



NOTE:  Ramified Microglia = Resting Microglia


The brain microglia play important roles in sensing even subtle variations of their milieu. Upon moderate activation, they control brain activity via phagocytosis of cell debris and production of pro-inflammatory mediators and reactive oxygen species. However, a persistent activation would make the microglia transfer into a status with an amoeboid morphology tightly associated with neuronal damage and pro-inflammatory cytokine overproduction.

Unlike the activated microglia, the un-stimulated microglia are in a ramified status with extensively branched processes, an contribute to brain homeostasis via regulation of synaptic remodeling and neurotransmission. The ramified microglia has been shown to be associated with the induction of M2 polarization. A study by McWhorter et al. showed that elongation of macrophage by control of cell shape directly increases the expression of M2 markers and reduces the secretion of proinflammatory cytokines, suggesting that induction of microglial ramification may be a mechanism for regulation of microglial function. Methods that trigger microglial ramification may help treat brain disorders associated with neuroinflammation.
In this study, we found that BHB induces a functional ramification of murine microglia in both basal and inflammatory conditions in vitro and in vivo. The pro-ramification effects of BHB are associated with the change in microglial polarization and phagocytosis as well as the antidepressant-like effects of BHB in LPS- or chronic unpredictable stress (CUS)-stimulated mice. The ramified morphology in microglia is also induced by two BHB-producing stimuli fasting and KD, as well as two other HDACs inhibitors valproic acid (VPA) and trichostatin A (TSA). Given that microglial overactivation can mediate the pathogenesis of depression, induction of microglial ramification by BHB may have therapeutic significance in depression. 

These data confirm that BHB has an ability to transform the activated microglia back to their ramified and resting status in inflammatory conditions.

Recall the recent post about BHB and the Niacin Receptor HCA2/GPR109A in Autism:

The Chinese paper continues:

It is HDACs inhibition but not GPR109A activation that mediates the pro-ramification effect of BHB in microglia Akt inhibition abrogates the effects of BHB on microglial ramification, polarization, and phagocytosis
Akt inhibition prevents the antidepressant-like effects of BHB in acute and chronic depression models

Note that Akt is another name for Protein Kinase B (PKB)

One of the major findings in the present study is that the ketone body metabolite BHB as well as its producing stimuli fasting and KD induced reversible ramifications of murine microglia in vitro and in vivo, and these ramifications were not altered by pro-inflammatory stimuli. The ramified morphology induced by BHB seems to be a signal upstream of microglial polarization, and may mediate the antidepressant-like effect of BHB in depression induced by neuroinflammatory stimuli. Since the regulating effect of BHB in disorders associated with neuroinflammation has been well-documented, our findings provide a novel mechanism for the explanation of the neuroprotective effect of BHB in neurodegenerative and neuropsychiatric disorders from the aspect of the feedback regulation of microglial function by microglial ramification.
Induction of microglial ramification, a strategy neglected by most scientists for a long time, may have more important therapeutic significance than that of regulation of microglial polarization alone at the molecular level.

In experiments in vivo, we showed that BHB ameliorated the depressive-like behaviors induced by two neuroinflammatory stimuli LPS and CUS. These results are in accordance with previous reports, which showed that the BHB-producing stimuli, caloric restriction and fasting, produce potential antidepressant-like activities in both animals and humans. Thus, together with the pro-ramification effect of BHB in microglia in vitro, we speculate that the microglial shape change may be an independent signal that determines microglial function.

Our further analysis showed that the BHB-induced microglial ramification was mediated by the Rac1-Cdc42 signal, as BHB markedly increased the activity of Rac1 and Cdc42, and Rac1/Cdc42 inhibition attenuated the pro-ramification effect of BHB. The PI3K-Akt signal has been shown to mediate the activation of Rac1/Cdc42, and once accepting the signal from Akt, the Rac1-Cdc42 will be mobilized to promote lamellipodia/filopodia formation and cell shape change (Huang et al., 2016a). We showed that the BHB-induced microglial ramification was mediated by the Akt signal, as Akt inhibition suppressed the induction of microglial ramification by BHB. As a functional evidence for the involvement of Akt in the pro-ramification effect of BHB, Akt inhibition was found to block the functional changes in BHB-treated microglia in vitro and in vivo, including blockage of the anti-inflammatory and prophagocytic activity of BHB and abrogation of the antidepressant-like effects of BHB. Since the ramified morphology determines the anti-inflammatory phenotype in macrophages (McWhorter et al., 2013), our data suggest that there may exist a causal relationship between the ramified morphology and microglial function after BHB treatment, and this relationship may evidence the clinical significance of our findings, as the microglial process retraction has been shown to mediate the development of neurodegenerative and neuropsychiatric disorders.

Furthermore, considering the serum level of BHB in humans begin to rise to 6 to 8 mM with prolonged fasting (Cahill, 2006), investigation of whether the pro-ramification effect of BHB exists in human individuals should be of great value for the application of BHB in disease therapy. 


 Exposure to hypobaric hypoxia causes neuron cell damage, resulting in impaired cognitive function. Effective interventions to antagonize hypobaric hypoxia-induced memory impairment are in urgent need. Ketogenic diet (KD) has been successfully used to treat drug-resistant epilepsy and improves cognitive behaviors in epilepsy patients and other pathophysiological animal models. In the present study, we aimed to explore the potential beneficial effects of a KD on memory impairment caused by hypobaric hypoxia and the underlying possible mechanisms. We showed that the KD recipe used was ketogenic and increased plasma levels of ketone bodies, especially β-hydroxybutyrate. The results of the behavior tests showed that the KD did not affect general locomotor activity but obviously promoted spatial learning. Moreover, the KD significantly improved the spatial memory impairment caused by hypobaric hypoxia (simulated altitude of 6000 m, 24 h). In addition, the improving-effect of KD was mimicked by intraperitoneal injection of BHB. The western blot and immunohistochemistry results showed that KD treatment not only increased the acetylated levels of histone H3 and histone H4 compared to that of the control group but also antagonized the decrease in the acetylated histone H3 and H4 when exposed to hypobaric hypoxia. Furthermore, KD-hypoxia treatment also promoted PKA/CREB activation and BDNF protein expression compared to the effects of hypoxia alone. These results demonstrated that KD is a promising strategy to improve spatial memory impairment caused by hypobaric hypoxia, in which increased modification of histone acetylation plays an important role

Exogenous BHB prevents spatial memory impairment induced by hypobaric hypoxia

To further verify whether ketone body, a product of KD, has direct improving effect, we chose the most stable physiologic ketone body, BHB, for the subsequent experiment. In order to mimic the effect of KD as above described, the rats were pre-treated with BHB (at a dose of 200mg/kg/day) for 2 weeks and then submitted to Morris water maze test. Since intraperitoneal injection would allow substances to be absorbed at a slower rate and intraperitoneal injection would produce marginal effect during behavioral tests [16], we used the intraperitoneal injection of BHB, which has been applied in published reports [17, 18]. Although the rats in the control and BHB groups learned to find the platform with the same pattern during 5 days of acquisition training (Fig 4B), BHB could significantly improve the memory impairment induced by hypobaric hypoxia, represented by more crossing number, more time in the target quadrant, and decreased latency to first entry to platform compared to hypobaric hypoxia treatment alone (Fig 4C–4F). These results demonstrated that BHB has a direct memory-improving effect and served as the main executor of KD beneficial effects.

KD increases histone acetylation modification in the hippocampus

A previous study found that BHB is an endogenous HDAC inhibitor, and the KD recipe in our study substantially increased plasma levels of BHB. Then, we detected the effect of KD on histone acetylation in the hippocampus, which is responsible for learning and memory. As shown in Fig 5, the acetylated histone H3 (K9/K14), acetylated histone H3 (K14), and acetylated histone H4 (K12), were all increased in the hippocampus of the KD rats. Although the histone acetylation modifications listed above are decreased in hypoxia-treated rats, KD treatment could reverse the decreased levels of histone acetylation. The same pattern was displayed in the immunohistochemical staining, in which the hypoxia-induced decrease in acetylated histone H3 and acetylated histone H4 in the CA1 region of the hippocampus was reversed by KD treatment  

KD activates PKA/CREB signaling in the hippocampus

To explore a possible underlying mechanism of the beneficial effect of KD treatment on cognition, the activity of the PKA/CREB pathway in the four groups was also evaluated by western blot (Fig 7A). KD treatment was shown to not only increase the levels of PKA substrates and p-CREB (KD vs STD) but also reverse the decline in PKA substrates, p-CREB and CREB (KD-Hy vs STD-Hy). Although KD pre-treatment produced a partial restoration of PKA activity, p-CREB is nearly completely restore to its basic levels, which is may be account for its other upstream kinases, like calmodulin-dependent kinases [19]. Interestingly, the hypoxia-induced down-regulation of BDNF, a well-known neurotrophic factor involved in learning and memory formation processes, was also up-reregulated by KD treatment. These results demonstrated that KD treatment promoted PKA/CREB activation and BDNF protein expression. In order to detect whether KD promoted BDNF expression at mRNA levels, qRT-PCR assays were performed using BDNF specific primers. We found that KD-pretreatment significantly increased mRNA levels compared with that in hypobaric hypoxia group (Fig 7B). Next, we used ChIP-PCR to test if there might be increased enrichment of acetylated histones on the promoter of BDNF gene. We focused on the promoter I of BDNF gene, which response to neuronal activity [20). ]. The results showed that there is increased binding of acetylated histone H3 to the promoter I of BDNF gene (Fig 7C   

Concentrations of acetyl–coenzyme A and nicotinamide adenine dinucleotide (NAD+) affect histone acetylation and thereby couple cellular metabolic status and transcriptional regulation. We report that the ketone body d-β-hydroxybutyrate (βOHB) is an endogenous and specific inhibitor of class I histone deacetylases (HDACs). Administration of exogenous βOHB, or fasting or calorie restriction, two conditions associated with increased βOHB abundance, all increased global histone acetylation in mouse tissues. Inhibition of HDAC by βOHB was correlated with global changes in transcription, including that of the genes encoding oxidative stress resistance factors FOXO3A and MT2. Treatment of cells with βOHB increased histone acetylation at the Foxo3a and Mt2 promoters, and both genes were activated by selective depletion of HDAC1 and HDAC2. Consistent with increased FOXO3A and MT2 activity, treatment of mice with βOHB conferred substantial protection against oxidative stress. 
Abnormalities in mitochondrial function and epigenetic regulation are thought to be instrumental in Huntington's disease (HD), a fatal genetic disorder caused by an expanded polyglutamine track in the protein huntingtin. Given the lack of effective therapies for HD, we sought to assess the neuroprotective properties of the mitochondrial energizing ketone body, D-β-hydroxybutyrate (DβHB), in the 3-nitropropionic acid (3-NP) toxic and the R6/2 genetic model of HD. In mice treated with 3-NP, a complex II inhibitor, infusion of DβHB attenuates motor deficits, striatal lesions, and microgliosis in this model of toxin induced-striatal neurodegeneration. In transgenic R6/2 mice, infusion of DβHB extends life span, attenuates motor deficits, and prevents striatal histone deacetylation. In PC12 cells with inducible expression of mutant huntingtin protein, we further demonstrate that DβHB prevents histone deacetylation via a mechanism independent of its mitochondrial effects and independent of histone deacetylase inhibition. These pre-clinical findings suggest that by simultaneously targeting the mitochondrial and the epigenetic abnormalities associated with mutant huntingtin, DβHB may be a valuable therapeutic agent for HD.  

Conclusion
At the end of this fifth post on ketones and autism, I think we have established beyond any doubt that ketones can do some amazing things for numerous dysfunctions and diseases.
The question remains how much you need to achieve the various possible benefits. 
The next question, already put to me by one parent, is how do you measure such a benefit.  Some people’s idea of treating autism is just to eradicate disturbing behaviours like SIB and ensure a placid, cooperative child when out in public.  Other people notice small cognitive and speech changes, because they spend hours a day teaching their child. Small but significant cognitive improvement may not show up on autism rating scales.
You would expect a dose dependent response, so the more ketones the bigger the response, which suggests that the full Ketogenic Diet (KD) is the ultimate option.
A lot does seem to be possible just with BHB and C8 (caprylic acid) as supplements to a regular diet.
Adults with Alzheimer’s, or Huntington’s, or Multiple Sclerosis (MS) all stand to potentially benefit from ketone supplements.
Children/adults with certain single-gene autisms, not limited to Kabuki and Pitt Hopkins potentially should benefit from ketone supplements.
Interestingly, another benefit of BHB is on mood; it seems to make some people just feel much better, apparently all due to the effect on microglia. So perhaps autism parents who take antidepressants should try BHB instead.