Geoff’s Narration

The GIST

 

“Together, these findings demonstrate that WASF3 suppresses oxidative metabolism in the brain and contributes to cognitive dysfunction, providing mechanistic insights into the “brain fog” reported in ME/CFS.” Hwang et al.

WASF3 – a mitochondrial-inhibiting protein – an already very interesting potential factor in ME/CFS – just got more interesting. (Thanks, Matthias, for the tip about the new study.) You can read about Paul Hwang’s fascinating saga with the mitochondrial inhibitor WASF3 in a past blog (see below).

Hwang, a senior intramural researcher at the NIH, first got interested in WASF3’s effects on the muscles. His finding that elevated WASF3 activity in ME/CFS was linked to disrupted mitochondrial activity could help explain the muscle fatigue found in ME/CFS.

He also found that reducing ER stress with a drug called salubrinal improved mitochondrial functioning in patient-derived cells. It appears that endoplasmic reticulum stress is the trigger that sets off WASF3, which then impacts the mitochondria.

The Study

WASF3 is also found throughout the brain, and Hwang earlier suggested the WASF3 problems he was seeing in the muscles might be present in the brain as well. His recent study, “Stress-inducible WASF3 regulates brain metabolism and cognitive function“, in the venerable Proceedings of the National Academy of Sciences (PNAS), suggests WASF3 could have a major impact on the brain.

Hwang used two different genetic techniques to produce mice without WASF3. One technique used CRISPR to delete the part of the gene that produces the WASF3 protein, but it did not find that deleting WASF3 impaired the mice.

Using something called “Cre-lox”, which also creates cellular stress, they found that increasing cellular stress in mice with WASF3, by contrast, resulted in altered “fear conditioning behavior” and learning. However, when they removed WASF3 from the mice, increased cellular stress did not reduce cognition.

This suggested that the key factor is not just increased WASF3 levels but cellular stress plus increased WASF3 levels. This fits with Hwang’s prior finding that increased endoplasmic reticulum stress was associated with increased WASF3 levels and impaired mitochondrial functioning.

A Close Look at the Hippocampus

Hwang found WASF3 throughout the mouse brain, but WASF3 levels were particularly high in three brain regions associated with ME/CFS: the amygdala, hippocampus, and cerebellum. Hwang then subjected hippocampal tissues to differing WASF3 levels.

The hippocampus plays an important role in short-term memory retention, emotions, spatial navigation, and learning.

Increasing WASF3 levels in those tissues reduced their oxygen levels by a startling 50%. The tissues were clearly under dramatically increased stress, as markers of mitochondrial oxidative metabolism, including ATPIF1 and MTCO1, and oxygen consumption rose.

The more WASF3 present, the worse complex IV of the mitochondrial electron transport chain functioned. Conversely, reducing WASF3 improved mitochondrial functioning.

Hwang and company next did a metabolomic analysis of those tissues. The fact that increasing WASF3 levels generally produced lower levels of several metabolites suggested WASF3 had put the brain into a hypometabolic or low-energy state – as some brain ME/CFS studies have suggested

For instance, decreased levels of glycolysis metabolites in high WASF3 mice suggested that: a) glycolysis wasn’t proceeding normally; and b) an attempt to compensate for reduced mitochondrial ATP production was underway.

Similarly, fats provide an important energy source, and some fat metabolites were reduced. Plus, increased levels of some fatty acids (medium-chain dicarboxylic acids pimelate, suberate, and azelate) suggested fatty acid metabolism had been disrupted.

Even peroxisomes, for those who remember Ian Lipkin’s big paper, got into the act. Lipids expected to accumulate when peroxisomes are dysfunctional increased. WASF3 also inhibited a histamine-derived metabolite called IAA, which triggers activity of the feel-good compound GABA.

Note that these studies are still very small – just five or six mice – but Hwang’s findings suggest that increased WASF3 levels are highly detrimental to the mitochondria.

The Real Target? The Brain… 

While Hwang found WASF3 in mitochondrial membranes in muscles in his earlier study, this time he found it in spades in the endoplasmic reticulum and the “mitochondria-associated membranes (MAMs”) in mouse brain cells.

Finding WASF3 in the MAMs surprised Hwang and is potentially important because it suggests WASF3 may affect much more than energy production. Besides energy production, these mitochondrial-associated membranes, or MAMs, also affect calcium transfer, lipid metabolism, stress signaling, and coordination of mitochondrial activity.

This suggests ER stress/WASF3 could also affect many aspects of neuronal functioning. Cognition, learning, and the ability to sustain mental activity could all be affected.

More Ways to Pummel the Mitochondria

As they dug deeper into WASF3’s effects on mitochondria, they found that increased WASF3 levels reduced levels of a compound called ATPIF1, which regulates how much ATP mitochondria produce. (WASF3 does this by increasing the levels of another protein that degrades ATPIF1. Reduced ATPIF1 was recently found in ME/CFS.)

Hwang’s findings now suggest WASF3 could be whacking the mitochondria in three ways: 

1. by interrupting the electron transport chain at complex IV.
2. by reducing how much ATP the mitochondria are asked to produce (low APIF1).
3. by impairing mitochondrial movement. There’s ATP production, and there’s getting the ATP to where it’s needed. Mitochondria should be able to move closer to where the cell needs energy. WASF3 also appears to impair that.

Hwang further tested WASF3’s ability to impact the mitochondria by introducing a chemotherapy agent known to produce “chemo-fog” and found that, in the presence of that agent, WASF3 inhibited complex IV in the electron transport chain in mitochondria of brain cells as well.

Interestingly, Hwang’s new paper also indicates that different parts of the WASF3 protein have different effects. He demonstrated that removing one part of the protein resulted in mitochondrial movement being restored, but complex IV in the electron transport chain was still affected.

The findings suggest that Hwang will likely dive deeper into WASF3’s molecular structure to understand the effects of different parts of the protein. These findings could have important treatment implications.

The Key – Cellular Stress

The fact that WASF3 appears to have particularly detrimental effects when cellular stress is present fits nicely with what happens in ME/CFS; i.e., that stress – whether it comes from physical or mental activity or emotional issues – makes things worse. At its core, ME/CFS seems to be a stress response disorder.

In this scenario, increased cellular stress increases WASF3, which then inhibits mitochondrial energy production. Fatigue and other symptoms result. Post-exertional malaise could be explained by a long-term reduction in the mitochondria’s ability to produce energy, accompanied by increased oxidative stress, and what have you.

Cautionary Note

The fact that Hwang continues to explore WASF3 in mice is an encouraging sign as they’re probably the next logical step for many researchers who want to understand what’s going on. The mouse findings cannot prove, though, that increased WASF3 levels cause mental or physical fatigue or cognitive problems in people with ME/CFS. We don’t know, for instance, that WASF3 levels are increased in the brains of people with ME/CFS.

The mouse studies suggest that if they are, they could be having quite an impact.

Almost In Spite of Itself, the NIH Turns Interesting

Say what you will about an NIH administration that has refused to sufficiently fund ME/CFS for decades; some really nice work is going on in the brain right now, and it’s mostly being driven by internal or intramural researchers who have latched onto the illness.

We have two senior intramural researchers (Hwang and Chung) digging into the mitochondria and the brain in their labs. We have an emeritus, highly accomplished neuroscientist (Goldstein) looking at norepinephrine and energy production, and a neuroscientist (Bedard) focused on the brain-muscle interaction.

These researchers got to ME/CFS in a variety of ways. Hwang came via a person with ME/CFS who happened to be in a family cancer study, Chung via a Solve M.E. board member whom he met at a wedding (!), and Goldstein and Bedard via Nath’s intramural study. Thanks to a Solve M.E. grant, an ME/CFS mouse study is underway in a most interesting drug.

As Hwang was uncovering WASF3’s impact on muscle mitochondria, Chung was producing a potentially powerful mitochondrial compound (IVO-21) that may affect WASF3. (A Solve M.E. grant is exploring that.)

Meanwhile, quite apart from the others, Goldstein proposed that reduced ATP production (energy again) caused the reduced norepinephrine activity he found.

Hwang’s latest finding suggests that WASF3 is not only present in more places in brain cells than in muscle cells, but could also interfere with mitochondria and ATP production in more ways than previously thought.

Plus, Bedard’s finding that ME/CFS patients’ muscle force declined rapidly during the handgrip test suggested that the brain-muscle system gets plastered under physical stress. Whether triggered by physical or mental activity or emotional distress, we’re talking about problems with energy production and stress at the cellular level. The big question right now is how much of that is due to WASF3 and ER stress.

Of course, Hwang examined mice, not humans, and we don’t know that WASF3 levels are increased in ME/CFS and long-COVID patients’ brains. Still, the signs, at least for now, are positive.

The big fly in the ointment right now is that the studies are still quite small. Before we can say WASF3 and ER stress are major factors in ME/CFS, these findings need validation and expansion in much larger studies.

The potential certainly seems there for a great deal of collaboration, but we don’t know if these groups are working together. Because these are intramural efforts, we don’t know how much funding is going into this research or what the next steps are.

As far as I can tell, there are no signs that a major study is currently underway. One would hope some grant applications are in. If the NIH has been looking for a reason to fund a major grant effort (a big if after all these years), I wonder what more they could want? These findings, after all, come from internal NIH researchers, mostly senior NIH researchers. If they don’t trust their results, who can they trust?

In any case, regarding Hwang’s latest finding, some further studies could determine if physical or cognitive stress really does increase WASF3 activity in ME/CFS, and if increased WASF3 levels are associated with an inability to sustain a handgrip test, aka Bedard, and/or reduced NE functioning/synthesis, aka Goldstein. A positive result to those studies would suggest researchers have identified a major player in ME/CFS.

Drug Trial Coming

A drug trial showing that reducing WASF3 levels reduces symptoms would, of course, be huge, and the good news is that Hwang told me an ME/CFS trial is in its final stages of approval. The only thing we know about that drug is that it has not been tested in ME/CFS before. (Paul Hwang has promised a Zoom interview sometime, probably in December, to discuss it.)

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