Health Update: Lions, Tigers, and Bears, Oh My! No lions or tigers, but plenty of bears (or at least one bear). A black bear swiped the dogs’ food while we were on a walk, then proceeded to disrupt things repeatedly at night, causing the dogs to bark and me to lose sleep.  (The bear never actually made it into camp).

The dogs – two approximately 80 lb Catahoula dogs – which were actually bred to track and fix bears, got theirs back by treeing the bear twice, and hopefully, that bear will move on. (This is only the 3rd bear encounter in 15 years of camping…)

 All this has been exciting and exhausting, and it’s set me back a bit.  With the heat, two fires, that uncaring forest service employee, and now this bear, it’s been a crazy summer! The good news is that I am continuing to improve, and I think the long-term outlook is good. 

Health Rising recently covered two NIH brain studies suggesting low energy levels in the brains of ME/CFS and/or long COVID patients. The first study found a dramatic reduction in energy availability in the cingulate cortex – a part of the brain involved in “effort”, pain sensitivity, autonomic nervous system activity, and more. The second suggested that low-energy conditions may keep the norepinephrine-producing neurons in the locus coeruleus from producing sufficient norepinephrine.

The blog pointed out several factors that could be producing the abnormalities found, but it left one out: Paul Hwang’s 2023 WASF3 finding.  Because Hwang is operating in a way that is unusual for us, it’s good to check out who he is and how he works.

 

Paul Hwang MD, PhD.

First, Paul Hwang is an intramural researcher; i.e., he is employed by the NIH. He is not the typical outside researcher we usually follow who submits grant proposals. That fact changes a lot.

Hwang joined the NIH in 2001 and has been a senior investigator in the Cardiovascular and Cancer Genetics Laboratory at the National Heart, Lung, and Blood Institute (NHLBI) since 2011. His main focus is mitochondrial regulation and cellular metabolism.

The NIH gives its senior investigators significant latitude over what they study. This lets them respond quickly to new findings, ramp up programs swiftly, and sustain them over long periods. Hwang, for instance, doesn’t have to submit his projects for peer review – always a potential danger for ME/CFS researchers.

Hwang’s funding depends on periodic reviews that show how much progress he’s making and how much funding the Scientific Director wants to give him.

But because he doesn’t have to take the time to write a large grant proposal, wait 6 months or so to get approved, and then wait for the funds to be disbursed, Hwang can follow his interests and move with lightning speed compared to outside extramural researchers we’re more familiar with.

In 2025, Hwang stated:

“It’s really hard to plan for discovery; instead, we follow the science, or, in this case, we follow the molecules. That’s one of the great things about NIH: we’re given the freedom to follow the science, and with my clinical background, do translational studies that bring clinical relevance to our findings about human biology.”

Hwang’s 2023 ME/CFS paper, “WASF3 disrupts mitochondrial respiration and may mediate exercise intolerance in myalgic encephalomyelitis/chronic fatigue syndrome,” was one of the most shocking ME/CFS studies I can remember.

Suddenly, a researcher with no prior experience in ME/CFS, working at an NIH institute (NHLBI) that has virtually ignored ME/CFS, produced a major paper on ME/CFS that offered an entirely new slant on the disease.

The fact that Hwang’s study included laboratory, genetically modified animal, and human studies makes it clear that at some point Hwang chose to take on ME/CFS in a big way.

The 2023 WASF3 Study

Hwang’s ME/CFS saga started with a family with a cancer-promoting gene mutation. Luckily for us, that family

included a 38-year-old woman with mysterious fatigue, which had started after a bout with infectious mononucleosis at age 16. Talk about serendipity.

Looking in her muscle tissue for evidence of the suspect gene, Hwang found abnormally high levels of WASF3 in the woman with fatigue (but not in the other family members).

He apparently latched onto ME/CFS when WASF3 popped up in an obscure 2011 ME/CFS study. That short paper – which used a novel gene-gene association technique – ended up focusing on WASF3. It stated that WASF3 “possibly regulates brain cytokines involved in the mechanism of fatigue through the p38 MAPK regulatory pathway.”

WASF3

WASF3 is best known for regulating the cell’s actin “skeleton” but can also disrupt mitochondrial functioning.

Hwang dug deeper and found that the fatigued woman had multiple mitochondrial abnormalities, including unusually prolonged recovery (phosphocreatine (PCr)) periods after exercise, a lower mitochondrial oxygen consumption rate (read energy production), a decreased ability to transfer electrons from complex III to complex IV in the electron transport chain of the mitochondria, and decreased cytochrome oxidase enzymes. No wonder the woman was so fatigued!

This made sense, as WASF3 can disrupt mitochondria by inhibiting part of the electron transport chain. Indeed, Hwang found that knocking down WASF3 levels in her cells improved mitochondrial function. He’d just discovered a new way to potentially explain the energy problems in ME/CFS.

Next, he created transgenic mice with high WASF3 levels in their skeletal muscles and stressed them with exercise. That resulted in higher blood lactate levels – a sign of mitochondrial distress, which is seen in ME/CFS – and lower glycogen levels. The mice also showed a significant reduction in endurance during a running test.

Nath’s Study Participants Take Center Stage

Next, Hwang brought in samples from ME/CFS patients in Nath’s intramural study. He and his colleagues found significantly increased WASF3 levels and dramatically reduced cytochrome oxidase and MTO1 levels. (MTO1 is a protein expressed in high-energy-demand tissues such as the muscles.)

So far, so good.

The Real Culprit Shows Up? (And the Viral Connection)

Looking upstream, Hwang found a dramatic reduction in an endoplasmic reticulum protein called BiP, which regulates WASF3 production. They apparently examined the endoplasmic reticulum (ER) because infections put the ER under considerable stress. Indeed, a marker of endoplasmic reticulum (ER) stress called PERK was high.

The endoplasmic reticulum regulates protein folding. Proteins, which do the work of the cell, are extremely complex structures that must be folded correctly to work. The high ER stress levels suggested that too many improperly folded proteins were present in the ME/CFS patients.

It turns out that the endoplasmic reticulum (ER) plays an important role in cellular viral defense.  Viruses attempt to counteract this by upregulating genes that impair its ability to properly fold proteins or remove misfolded ones.

The high WASF3 levels found in ME/CFS patients then appeared to result from an overstressed endoplasmic reticulum that could not properly regulate WASF3.

The authors concluded that:

“WASF3, induced by ER stress…(provides) a molecular explanation for the energy deficiency symptoms of exercise intolerance and postexertional malaise in a patient with chronic fatigue.

A Critically Important Process? 

Hwang was clearly quite interested in the role mitochondria play in ME/CFS because two years later, in 2025, his group published an overview, “Mitochondrial Dysfunction in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome“. The review, which highlighted exercise intolerance, suggested that the ER-WASF3 connection could be what we’re looking for: a “critically important cellular process” that affects many systems.

“ME/CFS could be a complex manifestation of multiple systems being affected by the derangement of a critically important cellular process that has wide-ranging effects depending on the characteristics of each tissue or organ.”

The authors noted that the mitochondria play a far larger role than just providing energy and cited over 20 studies suggesting the mitochondria have been affected in ME/CFS.

While substantial evidence suggests mitochondria are affected in ME/CFS, it’s not considered a mitochondrial disease because no genetic basis for the mitochondrial dysfunction is present. (Liz Worthey and Camille Birch argue that mitochondrial conditions can be “acquired”, that is, produced by non-genetic means over time in the body.)

The Big Shift

When the paper shifted to oxidative stress, something new emerged. The general understanding has been that because the mitochondria produce most of the free radicals, or reactive oxygen species, in the cell, damaged mitochondria in ME/CFS must be flooding our cells with these dangerous substances.

Hwang and Syed turned that idea on its head. Instead of being dangerous free-radical merchants, they portrayed mitochondria as containing the cell’s most “powerful antioxidant mechanism(s)”. (!)

The idea that the mitochondria may play an important antioxidant role has been around for over 30 years. It rests on the realization that while mitochondria do produce scads of potentially harmful reactive oxygen species, they also – at complex IV of the electron transport chain – turn most of those free radicals into water.

Mitochondria, in fact, contain a huge array of antioxidant factors (manganese superoxide dismutase (SOD2), glutathione and glutathione peroxidases, peroxiredoxins, mitochondrial thioredoxin (TRX2), thioredoxin reductase) designed to ensure that the vast majority of ROS are destroyed before they can cause damage.

More importantly, perhaps, because the mitochondria also take in free radicals from the cell and metabolize them to harmless substances, the mitochondria may actually play an essential role in keeping our cells free of damaging ROS (free radicals).

In a 2022 “State of the Art Review” “Mitochondria and oxygen homeostasis,” Hwang and Mori asserted that “insights gleaned from these basic mechanisms are likely to be important for understanding disease pathogenesis and developing strategies for maintaining health.”

The key point for ME/CFS, though, is that the mitochondria’s ability to keep cells healthy and clean depends entirely on having the energy needed to produce these antioxidants.

In their 2025 paper, Syed and Hwang proposed that mitochondria’s low energy status in ME/CFS means they can’t metabolize the ROS present, leading to the consistently high levels of oxidative stress found in this disease.

The real zinger, though, comes when WASF3 gets packed into the mitochondrial equation. It turns out that increased WASF3 levels disrupt the exact part of the electron transport chain (complex IV) responsible for cleaning up the reactive oxygen species in the mitochondria.

Inhibiting complex IV would decrease antioxidant and energy production, as well as increase reactive oxygen species levels.

A Potential Vicious Circle Emerges

Increased reactive oxygen species (ROS) levels could then loop back and damage the endoplasmic reticulum, creating a vicious circle: high ER stress, possibly caused by an infection, dysregulates WASF3. WASF3 damages the electron transport chain, reducing ATP production and increasing reactive oxygen species. Those reactive oxygen species further damage the ER, causing more WASF3 dysregulation, more mitochondrial damage, and on it goes. Syed and Hwang appear to be the first researchers to explicitly flesh out this process.

Once this self-reinforcing system, or vicious circle, is established, there’s no need for a pathogen to keep disrupting things.

Now we can see, at least in part, why Hwang is so fascinated by ME/CFS – the disease appears to perfectly fit their mitochondrial/major antioxidant thesis. WASF3 damages the core antioxidant process, which they believe gives mitochondria their superpower as the cell’s premier free-radical buster.

That’s not nearly the end of their hypothesis, though. Over time, Hwang and company have really worked this problem…

A Pathogen Fighter as Well?

They propose that this WASF3 upregulation is usually a short-lived adaptive change that helps the body fight off an infection. WASF3  does this by downregulating ATP production and upregulating glycolysis – the primary energy source immune cells use when they ramp up to fight an infection.

The potential problem in ME/CFS and related diseases occurs when this temporary adaptive change becomes chronic, and immune cells get stuck in anaerobic energy-production mode. (More on that below).

Note that the increased reliance on glycolysis or anaerobic energy production fits what the ME/CFS and long COVID exercise studies have found. Lactate increases when the cell can no longer produce energy aerobically and is forced to rely on the dirtier, much (much) less efficient, and less productive anaerobic energy pathways.

Hwang has produced a highly integrated and coherent hypothesis. If he is right, then exercise should cause WASF3 levels, ER stress markers, and reactive oxygen species (free radicals) in the muscles to skyrocket, and complex IV, ATP production, and antioxidant levels to decline.

Back to the “Critically Important Cellular Process”

Remember the “critically important cellular process” Syed and Hwang proposed could dysregulate systems across the body? Because WASF3 is found in many cells across the body (brain and retina, muscle, epithelial tissues, immune cells, and reproductive tissues), it could dysregulate many systems.

Immune System

Towards the end of the 2025 paper, they suggested that the mitochondrial insufficiency they’d found in the muscles could be affecting immune cells. Because WASF3 hasn’t been well studied in immune cells, they presented this as a possibility to be tested.

They focused on T and B cells, both of which have become a major area of interest in ME/CFS.

WASF3 could disrupt these cells in several ways. Its ability to regulate actin could impact signaling, migration, calcium entry, and interaction with antigen-presenting cells. Ultimately, it could impair their ability to interact with invaders.

Perhaps more importantly, WASF3 could affect energy production. While T-cells use glycolysis to ramp up and produce clones, they then rely on aerobically produced energy. Mature T-cells stuck in glycolytic mode by increased WASF3 levels would have trouble recognizing and killing infected cells, and would be inflammatory, too.

T-cell exhaustion seems like an expected outcome and offers another test: does stimulating T-cells increase WASF3 levels, impair aerobic respiration and increase glycolysis, cause calcium issues, etc.?

The insufficiency of the adaptive immune process (T and B cells) and the compensatory response of the highly inflammatory innate immune system in ME/CFS seems well established.  By whacking the mitochondria in the T and B cells, WASF3 could conceivably account for that.

The problem would show up not necessarily in the initial response to pathogens but in a sustained response to pathogens

Interestingly, because the JAK2/STAT3 pathway can also regulate WASF3 levels, JAK/STAT inhibitors – which are being assessed in long COVID – could be helpful. In fact, bariticinib which is currently being tested in the huge (n=550) long COVID trial, might be one of the better inhibitors to try.

Hypometabolic Muscles, Too?

“For example, in disorders associated with immune and exercise tolerance abnormalities such as ME/CFS, it could be speculated that the innate immune activation caused by exercise stress may contribute to the clinical symptom of post-exertional malaise.” The authors

The authors propose that during exercise, weakened mitochondria release a danger-associated molecular pattern (DAMP) called mtDNA into the cell interior (cytosol).

That produces a location problem. mtDNA looks fine in the mitochondria, but once it enters the cell interior (cytosol), it looks like viral DNA to the immune system.

The innate immune system immediately goes on the attack. Energy production in muscle tissue drops, causing a prolonged metabolic shutdown. Reactive oxygen species (free radicals) levels skyrocket. Muscle repair mechanisms that should kick in after exercise get dramatically delayed.

The result: the muscles now exist in a hypometabolic, antiviral‑like state.

As the muscles spill cytokines and danger signals into the bloodstream, the vagus nerve activates nervous system circuits that tell the brain to produce the symptoms associated with “sickness behavior” to cause the patient to isolate themselves. The result: the big functioning hit and flu-like symptoms that pervade ME/CFS.

The difference is that, in this case, the symptoms are produced not by a virus but by a condition in the muscle cells (mtDNA) that mimics a viral attack.

Hence the authors suggestion:

“It could be revealing to investigate whether PEM, a key symptom of ME/CFS with neuroimmune features, is mediated in part by the mitochondrial innate immune signaling mechanism involved in skeletal muscle adaptation to exercise.

The Brain, Too?

And then there’s the brain. The authors wrote:

“Given the high energy demands of neurons for action potential generation and cell signaling, decreased mitochondrial respiration could affect brain function in unpredictable ways given the complexity of neuronal circuitries.”

and

“Because WASF3 is highly expressed in brain tissue, it is also tempting to speculate that disruption of WASF3 homeostasis could be involved in neuroinflammation as observed in ME/CFS.”

WASF3 is indeed found in many parts of the brain. Interestingly, it’s particularly abundant in the two brain regions which recent NIH studies suggest may exhibit reduced energy levels: the cingulate cortex and the locus coeruleus.

Because WASF3 is found in neurons and astrocytes, it could contribute to both reduced norepinephrine activity (neurons) and neuroinflammation (indirectly via astrocytes).

Indeed, the WASF3 finding predicts that the NE-producing neurons would act as Goldstein and Aregawi found. They might start off normally, but as they became more stressed, they would quickly fail. WASF3, then, would also produce the increasing inability of ME/CFS patients to maintain a steady handgrip force – as the MRS brain findings suggested.

Ultimately, it could affect the effort/supplementary motor cortex/motor cortex/muscle recruitment issues recent papers suggest may be occurring.

A nice potential brain connection has emerged. One wonders if Hwang is working with Goldstein and/or Bedard at the NIH to explore it?

Connective Tissue Connection?

WASF3 may have one more trick up its sleeve.  As noted earlier, WASF3 regulates actin, which makes up the “skeleton” of the cell, and is also involved in extracellular matrix (ECM) remodeling. Enter Rob Wust’s group, which found extensive ECM remodeling in muscle tissue that Slaghekke believes may be interfering with capillary blood flow to the muscles.

ECM remodeling, aka connective tissue remodeling, could be contributing to many issues in ME/CFS. Could WASF3 be contributing to this? This is also highly conjectural, but the potential connection seems to be there.

Endoplasmic Reticulum Stress: Take II

WASF3 could be doing a lot of damage, but Hwang’s findings suggest that endoplasmic reticulum stress is driving the high WASF3 levels. He was, after all, able to reduce WASF3 and restore mitochondrial functioning in the original patient’s cells with a drug that affects the endoplasmic reticulum.

In 2025, a small study (n=22) from Maureen Hanson’s lab, “Extracellular vesicle proteomics uncovers energy metabolism, complement system, and endoplasmic reticulum stress response dysregulation postexercise in males with myalgic encephalomyelitis/chronic fatigue syndrome,” brought ER stress to the fore.

Fortunately, the Glass/Hanson study used exercise as a stressor. Hwang’s study suggested that exercise should increase ER stress but could not test that. The Hanson group found that exercise dramatically increased ER stress – and that stress was strongly correlated with PEM symptoms.

The Hanson group’s study went beyond what Hwang achieved in his more limited study. BiP – the stress protein Hwang found dysregulated in muscle tissue – was dysregulated in the extracellular vesicles as well, but so were 9 other ER stress proteins. That suggested exercise had produced a broad dysregulation of the ER stress response. They also found a broad downregulation of proteins associated with aerobic energy production and other metabolic pathways. The authors wrote:

“Collectively, this highlights ER stress and protein folding as key therapeutic targets warranting further investigation.”

The fact that an independent lab exploring a different compartment of the body found similar evidence of ER stress was pretty compelling. The main issue – it was another small study….

Treatment Possibilities

If ER stress and WASF3 elevations are causing trouble in ME/CFS and related diseases, what to do about them? Hwang definitely has ideas. Whether he can test them is another question.

In 2023, Hwang stated he hoped to “embark on clinical studies” to improve energy levels in ME/CFS. In a 2023 LinkedIn post, one of Hwang’s co-authors, Jin Ma, reported the same thing (and posted a link to the Health Rising article :)). In Jan. 2025, in an NIH Advocacy call, Avindra Nath reported that Hwang was “going to do a small clinical trial”.

Everything seems to have stopped after that. They may have trouble finding the right drug.

Salubrinal – the drug he used to reverse WASF3 levels in patient one’s cells – is not FDA-approved. Interestingly, a 2024 paper from Nova Southeastern (home of Nancy Klimas’s lab) proposed using salubrinal to reduce ER stress and enhance cellular stress pathways in ME/CFS and long COVID.

Relyvrio seemed like a likely option until, in 2024, it failed a large ALS trial, prompting the drug company to withdraw it from the US and Canadian markets and the FDA to revoke its approval.

Almost a year later, Nath still reported that a small clinical trial was going to be done, indicating that Hwang had other options (sodium phenylbutyrate (Pheburane) and/or taurursodiol, guanabenz?).

However, an extensive ChatGPT search could not find references to an ongoing trial. Hwang still lists ME/CFS as a research focus on his NIH page, so he appears to still be involved, but no evidence indicates that a trial has. or is about to take place.

Conclusion

WASF3/ER stress clearly has the potential to be a “critically important cellular process” that can disrupt many systems.

Is it? Could a basic mitochondrial problem be the key? Or is the WASF3 hypothesis another beautiful hypothesis, as Robert Phair has noted, that our very complex body ends up rejecting? Time will tell.

One nice thing is that Hwang appears to be operating in a potentially rich environment right now with NIH researchers looking at the muscles and the brain in potentially interconnected ways. Are they working together? We don’t know.

Note that we’re still very much stuck in a rather familiar place – we’re in intriguing results/small study mode! Small studies from Hwang, Goldstein, Berdard, Wust, Hanson’s group, Prusty, and many others are driving the field forward in potentially fruitful ways.

We’re just missing the next step – launch mode – which involves large studies that can validate and expand the smaller study results.

We’re not in a terrible place – we’re in a MUCH better place than we were five years ago – but thus far, major funders like the NIH haven’t been willing to step up, put on their big-boy pants, and fund some major grant projects. That’s when things will really start happening. (Let’s hope that ME/CFS advocates can get Congress to allocate $50 million for the ME/CFS roadmap.)

Because Hwang is an intramural researcher, it’s hard to know exactly what he’s working on. We know he has plenty of latitude to explore different options – and has used that latitude to dig deeply into WASF3 and ME/CFS but what he’s doing now, how much funding he has, who he’s working with, whether a clinical trial is in the works, whether he’s able to bring in new patients, etc., is unclear. I will try to find out.

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