Health-related quality of life in people with ME and Long Covid: A conversation with Breanna Weigel, Griffith University, Australia

By Dylan Murphy

In March 2024 the UN Disabilities Committee issued a damning report which stated that disabled people in the UK faced systemic violations of their human rights ranging from cuts to benefits to the lack of housing for disabled people. Fast forward to late February 2025 and the UN Economic and Cultural Committee issued a report on the UK which criticized the Labour government for its failures to reduce poverty and social inequality. Since then our government in its infinite wisdom has decided to slash £7 billion from disability benefits and is removing free bus passes from hundreds of thousands of disabled people on PIP.

On the ME front our government has engaged in endless gas lighting postponing the Department of Health care plan for ME several times. It claims that the care plan for ME will be published sometime in June just when it is due to announce major cuts to public spending which makes it very unlikely that it will put any resources into funding this plan.

In 2017 I put in a freedom of information request to the DWP which revealed that a third of pwME applying for PIP were having their applications turned down. The DWP is of course completely ignorant of the heavy disease burden of ME on those suffering with this wretched illness. It chooses to ignore the wealth of scientific evidence revealing the low quality of life outcomes for pwME.

In light of the above developments I came across a recent research paper, Health-related quality of life in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome and Post COVID-19 Condition: A systematic review, by a group of scientists from the  National Centre for Neuroimmunology and Emerging Diseases (NCNED) at Griffith University, Australia.

One of the co-authors of the above paper, Breanna Weigel, took time out from her busy schedule to talk to me about this important piece of research which may be of value to those pwME navigating the treacherous waters which are our current benefits system. It was such a pleasure to talk to a passionate young scientist who is so committed to the field of ME/Long Covid research. Breanna told me, “ It is a privilege to share these findings with the ME and Long COVID community, who have had an immeasurable impact on my growth as a researcher and my passion for making a difference for people who live with these chronic illness.’’

Breanna Weigel has five years’ experience working in the field of ME/CFS and Long COVID research at the National Centre for Neuroimmunology and Emerging Diseases (NCNED), Griffith University, Gold Coast, Australia. This month, Breanna will be submitting her PhD thesis, titled “Living with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome and Long COVID in Australia: An examination of illness experiences and healthcare policy”.

DM: How did you get involved in the field of ME research?

BW: Chronic illness has been an important part of my life and an area that I have wanted to work in for a long time. My Mum has lived with a chronic illness that has affected her life every day for the last 23 years. Seeing the extensive impacts that this had on my Mum, I was motivated to pursue a career that enabled me to contribute to helping people with chronic illness. I also developed a chronic illness four years ago, which considerably disrupted my life. However, my own lived experiences have provided me with additional insight that has informed my approach to research.

My involvement in ME research commenced in 2019 during my search for a supervisor for my Honours project. As I had a strong interest in public health and epidemiology, my program advisor shared with me the public health research that was being conducted at the National Centre for Neuroimmunology and Emerging Diseases (NCNED) and put me in contact with Prof Sonya Marshall-Gradisnik. It was then that I was introduced to the world of ME research.

I have continued to work with the NCNED over the last five years and I am presently finalising my PhD thesis, which highlights the lived experiences of people with ME and people with Post COVID-19 Condition (PCC). Throughout my early research career, I have had the invaluable opportunity to work directly with people who live with these conditions. Hearing their stories and experiences of living with ME or PCC has strengthened my motivation to make a difference for people who live with chronic illnesses that affect so many aspects of life.

DM: In the paper you co-authored, “Health-related quality of life in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome and Post COVID-19 Condition: A systematic review”, you make the following observation: “people with ME/CFS (pwME/CFS) and people with PCC (pwPCC) are often precluded from accessing necessary disability and social support services. These unmet care needs exacerbate the existing illness burdens experienced by pwME/CFS and pwPCC.’’

This is a very timely and astute observation.

In October 2023 the Department of Health UK held a public consultation regarding its plans to improve the quality of life for people with ME, which admitted that people with ME face many difficulties accessing disability and social care services. Now we face huge cuts to disability benefits such as Personal Independence Payment (PIP), which many people with ME claim to help them with the extra costs of being disabled. Due to the fluctuating nature of the illness many people with ME have problems claiming disability benefits and accessing social care services.

Bearing this in mind can you explain the purpose of your systematic review?

BW: Unfortunately, many people with ME and people with PCC face similar barriers to receiving such necessary support in Australia. Based on results in my Honours and PhD research, approximately half of the people with ME who participated in these studies and were unable to work due to their illness were not receiving income support through the Disability Support Pension (DSP), which is our federally funded income assistance program here in Australia.

A primary barrier to accessing this necessary support for Australians who live with ME or PCC is the lack of recognition for these illnesses as real, physical disabilities in healthcare policy. The purpose of our recently published systematic review was, therefore, to elucidate that the profound impacts of ME and PCC on the health and functioning of people who live with these conditions warrant access to care and support services, such as the DSP.

The systematic review method enabled all relevant studies published worldwide to be included in the analysis. By examining all the existing relevant literature, this systematic review not only provided evidence that ME and PCC are associated with significantly lower quality of life when compared with healthy people, but also indicated that these findings are consistent across studies, countries and time.

DM: Sadly, pwME over many years have suffered from a dismissive and discriminatory attitude from many health professionals and media outlets with their illness being dismissed as psychosomatic in nature. Here in the UK, we still have some of the royal medical colleges maintaining that psychological therapies are an appropriate treatment for pwME. Many people with Long COVID are facing similar negative attitudes towards their illness. Based on the extensive research which you carried out for your systematic review, how would you characterize ME and Long COVID: Are they physical or psychological illnesses?

BW: The findings of our recent systematic review reiterate that ME and PCC are real, physical illnesses that are not psychogenic in nature. I use the term, “PCC”, here as our systematic review specifically examined publications documenting quality of life among people with persistent COVID-19-related symptoms for at least three months, which is consistent with the World Health Organization’s definition of “Post COVID-19 Condition” (PCC).

Importantly, the illness impact trends observed across the studies analyzed in our systematic review highlight that physical health and the ability to complete daily activities are consistently the most substantially impacted components of quality of life among people with ME and people with PCC. In addition, mental health was consistently the least impacted component of quality of life among these two cohorts. These findings affirm that, whilst living with an invisible and incurable chronic illness can have significant mental health repercussions, these impacts are secondary to and not causative of ME or PCC.

This conclusion is supported by the extensive literature documenting disruptions to cellular functioning among people with ME and people with PCC. This includes the world-first research from the NCNED. Laboratory-based studies from our Centre have consistently identified impaired TRPM3 calcium ion channel function among people * with ME and people with PCC, in which these impairments are absent in healthy people. * see footnote for explanation of this term.

DM: People with ME suffer from a multitude of symptoms which have a very debilitating and disabling impact on their lives. Can you explain the disabling impact of the illness on people with ME and its long-term impact on them? Do people with Long COVID suffer from the same issues?

BW: Our systematic review, for the first time, provides consistent evidence of the shared widespread impact of ME and PCC on the health and well being of people with these conditions. Overall health, as well as all individual aspects of health and functioning, are considerably poorer among pwME and pwPCC when compared with healthy people.

In conjunction with the results of two other studies that contribute to my PhD project (which were published in 2024 [1, 2]) and the NCNED’s laboratory findings [3, 4], the illness impact patterns observed in our systematic review indicate that the collection of post-COVID-19 sequelae (an after effect of a disease, condition, or injury)  includes an illness presentation that is highly reminiscent of ME.

Combined with the post-viral nature of a considerable proportion of ME cases, this suggests that, after an episode of COVID-19, some people may experience the typical illness trajectory of people with ME. Hence, people who experience ME-like illness after COVID-19 may be at risk of long-term, complex chronic illness associated with widespread and debilitating symptoms, profound limitations on their ability to participate in daily, work and social life, and high healthcare needs.

DM: During the discussion section of your paper, you observe that pwME and people with Long COVID suffer from a comparable, profound level of disability. You note that “the illness presentation of ME/CFS and PCC poses a considerable barrier to completing physical tasks associated with daily living, …’’ Can you please explain this observation with examples from your research?

BW: The ability to participate in typical daily activities was consistently one of the most impacted components of health and functioning across the studies captured in our systematic review. In the context of the patient-reported outcome measures that were used to collect data in these studies, this refers to the ability to complete work both around the home and in relation to employment or study.

Such patient-reported outcome measures used by the studies included in our systematic review (and used in our studies at the NCNED) quantify quality of life and functioning across a range of scales. These include scales that consider overall health, as well as collections of more specific scales that focus on individual aspects of health. In terms of overall health, our research indicates that most people with ME/CFS and people with PCC have a functional status between 30% and 50% of total functioning. This is significantly lower than the level of functioning of healthy people, who typically return a score of (or close to) 100%.

Overall health status scores between 30% and 50% represent a considerable impact on the ability to complete daily activities, such as only being able to complete a limited number of tasks (like housework or grocery shopping) per day with adequate rest periods. However, people experiencing severe illness can return overall health status scores of 20% or 10%. People who return these considerably low scores may be mostly bed bound and unable to shower or eat independently.

The consistent finding that people with ME and people with PCC have a profoundly impaired ability to perform typical daily activities (including being able to continue employment) in our systematic review is critical in relation to guiding care and support access. As these impairments were repeatedly observed through the collection of data by validated and standardised patient-reported outcome measures, this provides evidence that ME and PCC are real, disabling conditions and must be considered eligible for care and support services, such as income assistance.”

DM:  Your study is the first systematic review to capture and compare quality of life metrics for both pwME and people suffering from Long COVID. In your paper, you state “The present systematic review therefore serves to elucidate the pervasive impacts of ME/CFS and PCC on people who live with these conditions to inform and guide healthcare policy reform, as well as future research.” What recommendations would you suggest to public health agencies and governments to help pwME and Long COVID have a better quality of life?

BW: The co-production of healthcare policies and services with ME and PCC consumers will be an essential step in improving quality of life for people who live with these conditions. Importantly, care accessibility must be increased for these cohorts and the processes of accessing care must accommodate for the functional limitations of people who live with ME or PCC.

DM: I had the opportunity to further discuss the role of consumers’ lived illness experiences in shaping healthcare policy in my recent collaboration with the Deeble Institute for Health Policy Research, Australian Healthcare and Hospitals Association, which can be accessed via this link: https://doi.org/10.25916/b246-r560

BW: If anyone has any questions after reading the interview or would like to discuss our research in general, they are more than welcome to contact us at ncned@griffith.edu.au

References:
1. Weigel B, Eaton-Fitch N, Thapaliya K, & Marshall-Gradisnik SM. Illness presentation and quality of life in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome and Post COVID-19 Condition: A pilot Australian cross-sectional study. Qual Life Res. 2024,33(9):2489–507. doi: 10.1007/s11136-024-03710-3.
2. Weigel B, Eaton-Fitch N, Thapaliya K, & Marshall-Gradisnik SM. A pilot cross-sectional investigation of symptom clusters and associations with patient-reported outcomes in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome and Post COVID-19 Condition. Qual Life Res. 2024,33(12):3229–43. doi: 10.1007/s11136-024-03794-x.
3. Martini Sasso E, Muraki K, Eaton-Fitch N, Smith P, Lesslar OL, Deed G, et al. Transient receptor potential melastatin 3 dysfunction in Post COVID-19 Condition and Myalgic Encephalomyelitis/Chronic Fatigue Syndrome patients. Mol Med. 2022,28(1):98. doi: 10.1186/s10020-022-00528-y.
4. Martini Sasso E, Muraki K, Eaton-Fitch N, Smith P, Jeremijenko A, Griffin P, et al. Investigation into the restoration of TRPM3 ion channel activity in Post-COVID-19 Condition: A potential pharmacotherapeutic target. Front Immunol. 2024,15:1264702. doi: 10.3389/fimmu.2024.1264702.

Glossary

* What is TRPM3? Imagine TRPM3 as a tiny “gate” on the surface of cells. This gate specializes in allowing calcium ions (charged particles) to flow into the cell when triggered. Calcium acts like a messenger, telling the cell to perform specific tasks.

How Does It Work? 

Triggers: The TRPM3 gate opens in response to certain signals, such as heat (like a body temperature rise) or specific molecules (like those released when you’re injured or when blood sugar is high). – Calcium’s Role: Once the gate opens, calcium rushes in, acting like a text message that alerts the cell to take action. This could mean sending a pain signal, releasing hormones, or adjusting to temperature changes.

1. Calcium Signaling & Cellular Stress: What’s Happening?

TRPM3 allows calcium to enter cells, which is critical for communication between nerves, muscles, and the immune system. In ME/CFS, abnormal calcium flow might disrupt this communication.

Impact: Too much calcium in cells (due to overactive TRPM3) could cause “cellular stress,” damaging mitochondria (the cell’s energy factories) or overstimulating nerves. This might explain the fatigue, muscle weakness, and “brain fog” seen in ME/CFS.

2. Pain Sensitivity & Nervous System Overdrive – What’s Happening?

TRPM3 helps nerves detect pain and temperature. If it’s hypersensitive, it might send constant “false alarms” to the brain.

Impact: This could contribute to chronic pain, allodynia (pain from light touch), or temperature intolerance (feeling too hot/cold) common in ME/CFS. It might also worsen “sensory overload,” where lights, sounds, or movement feel overwhelming.

3. Immune System & Inflammation – What’s Happening?

TRPM3 is activated by inflammatory molecules. In ME/CFS, chronic inflammation or immune dysfunction (e.g., after infections like Epstein-Barr virus) might keep TRPM3 stuck in the “on” position.

Impact: This could lead to a vicious cycle: inflammation → TRPM3 overactivity → more inflammation → worsened symptoms. Studies show ME/CFS patients often have abnormal immune cells (like natural killer cells), and TRPM3 defects in these cells might impair their ability to fight infections.

4. Energy Metabolism & Crashes – What’s Happening?

TRPM3 helps regulate insulin release and cellular energy. If it malfunctions, cells might struggle to manage glucose (sugar) for energy.

Impact: This could worsen energy crashes (post-exertional malaise) and contribute to the “dead battery” feeling in ME/CFS. Poor calcium regulation in muscles might also explain why even mild activity leads to severe fatigue.

5. The Bigger Picture: A Key Piece of the Puzzle?

ME/CFS is likely caused by a mix of genetic, immune, and environmental factors. TRPM3 dysfunction could be one piece of this puzzle. For example: – Genetic mutations in TRPM3 might make some people more prone to ME/CFS.

Viral infections or toxins could “break” TRPM3, triggering symptoms.

Overactive TRPM3 in the brain might disrupt sleep/wake cycles or hormone regulation.

Hope for Treatments? Researchers are exploring drugs that target TRPM3 to: ✅ Calm overactive channels (e.g., using blockers like primidone or certain antidepressants). ✅ Reduce inflammation linked to TRPM3 activation. ✅ Improve cellular energy by restoring calcium balance. However, this is still experimental—no treatments exist yet specifically for TRPM3 in ME/CFS.

Key Takeaway: TRPM3’s role in ME/CFS highlights how tiny cellular “gates” can have big impacts on fatigue, pain, and immune function. While more research is needed

Potential pathophysiological role of the ion channel TRPM3 in myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) and the therapeutic effect of low-dose naltrexone

Abstract:

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a debilitating disease with a broad overlap of symptomatology with Post-COVID Syndrome (PCS). Despite the severity of symptoms and various neurological, cardiovascular, microvascular, and skeletal muscular findings, no biomarkers have been identified.

The Transient receptor potential melastatin 3 (TRPM3) channel, involved in pain transduction, thermosensation, transmitter and neuropeptide release, mechanoregulation, vasorelaxation, and immune defense, shows altered function in ME/CFS. Dysfunction of TRPM3 in natural killer (NK) cells, characterized by reduced calcium flux, has been observed in ME/CFS and PCS patients, suggesting a role in ineffective pathogen clearance and potential virus persistence and autoimmunity development.

TRPM3 dysfunction in NK cells can be improved by naltrexone in vitro and ex vivo, which may explain the moderate clinical efficacy of low-dose naltrexone (LDN) treatment. We propose that TRPM3 dysfunction may have a broader involvement in ME/CFS pathophysiology, affecting other organs. This paper discusses TRPM3’s expression in various organs and its potential impact on ME/CFS symptoms, with a focus on small nerve fibers and the brain, where TRPM3 is involved in presynaptic GABA release.

Source: Löhn M, Wirth KJ. Potential pathophysiological role of the ion channel TRPM3 in myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) and the therapeutic effect of low-dose naltrexone. J Transl Med. 2024 Jul 5;22(1):630. doi: 10.1186/s12967-024-05412-3. PMID: 38970055; PMCID: PMC11227206. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11227206/ (Full Text)

Novel characterization of endogenous transient receptor potential melastatin 3 ion channels from Gulf War Illness participants

Abstract:

Gulf War Illness (GWI) is a chronic condition characterized by multisystem symptoms that still affect up to one-third of veterans who engaged in combat in the Gulf War three decades ago. The aetiology of GWI is mainly explained by exposure to multiple toxic agents, vaccines, and medications. As there is a significant overlap in symptoms between GWI and Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS), the objective of this study was to investigate a biomarker widely reported in Natural Killer (NK) cells from ME/CFS patients, the Transient Receptor Potential Melastatin 3 (TRPM3) ion channel.

NK cells from 6 healthy controls (HC) and 6 GWI participants were isolated, and TRPM3 function was assessed through whole-cell patch-clamp. As demonstrated by prior studies, NK cells from HC expressed typical TRPM3 function after pharmacomodulation.

In contrast, this pilot investigation demonstrates a dysfunctional TRPM3 in NK cells from GWI participants through application of a TRPM3 agonist and confirmed by a TRPM3 antagonist. There was a significant reduction in TRPM3 function from GWI than results measured in HC. This study provides an unprecedented research field to investigate the involvement of TRP ion channels in the pathomechanism and potential medical interventions to improve GWI quality of life.

Source: Marshall-Gradisnik S, Martini Sasso E, Eaton-Fitch N, Smith P, Baraniuk JN, Muraki K. Novel characterization of endogenous transient receptor potential melastatin 3 ion channels from Gulf War Illness participants. PLoS One. 2024 Jun 25;19(6):e0305704. doi: 10.1371/journal.pone.0305704. PMID: 38917121; PMCID: PMC11198784. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11198784/ (Full text)

Investigation into the restoration of TRPM3 ion channel activity in post-COVID-19 condition: a potential pharmacotherapeutic target

Abstract:

Introduction: Recently, we reported that post COVID-19 condition patients also have Transient Receptor Potential Melastatin 3 (TRPM3) ion channel dysfunction, a potential biomarker reported in natural killer (NK) cells from Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) patients. As there is no universal treatment for post COVID-19 condition, knowledge of ME/CFS may provide advances to investigate therapeutic targets. Naltrexone hydrochloride (NTX) has been demonstrated to be beneficial as a pharmacological intervention for ME/CFS patients and experimental investigations have shown NTX restored TRPM3 function in NK cells. This research aimed to: i) validate impaired TRPM3 ion channel function in post COVID-19 condition patients compared with ME/CFS; and ii) investigate NTX effects on TRPM3 ion channel activity in post COVID-19 condition patients.

Methods: Whole-cell patch-clamp was performed to characterize TRPM3 ion channel activity in freshly isolated NK cells of post COVID-19 condition (N = 9; 40.56 ± 11.26 years), ME/CFS (N = 9; 39.33 ± 9.80 years) and healthy controls (HC) (N = 9; 45.22 ± 9.67 years). NTX effects were assessed on post COVID-19 condition (N = 9; 40.56 ± 11.26 years) and HC (N = 7; 45.43 ± 10.50 years) where NK cells were incubated for 24 hours in two protocols: treated with 200 µM NTX, or non-treated; TRPM3 channel function was assessed with patch-clamp protocol.

Results: This investigation confirmed impaired TRPM3 ion channel function in NK cells from post COVID-19 condition and ME/CFS patients. Importantly, PregS-induced TRPM3 currents were significantly restored in NTX-treated NK cells from post COVID-19 condition compared with HC. Furthermore, the sensitivity of NK cells to ononetin was not significantly different between post COVID-19 condition and HC after treatment with NTX.

Discussion: Our findings provide further evidence identifying similarities of TRPM3 ion channel dysfunction between ME/CFS and post COVID-19 condition patients. This study also reports, for the first time, TRPM3 ion channel activity was restored in NK cells isolated from post COVID-19 condition patients after in vitro treatment with NTX. The TRPM3 restoration consequently may re-establish TRPM3-dependent calcium (Ca2+) influx. This investigation proposes NTX as a potential therapeutic intervention and TRPM3 as a treatment biomarker for post COVID-19 condition.

Source: Etianne Martini Sasso, Katsuhiko Muraki, Natalie Eaton-Fitch, Peter Smith, Andrew Jeremijenko, Paul Griffin, Sonya Marshall-Gradisnik. Investigation into the restoration of TRPM3 ion channel activity in post-COVID-19 condition: a potential pharmacotherapeutic target. Front. Immunol., 02 May 2024; Sec. Multiple Sclerosis and Neuroimmunology; Volume 15 – 2024 | https://doi.org/10.3389/fimmu.2024.1264702. https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2024.1264702/full (Full text)

Altered TRPM7-Dependent Calcium Influx in Natural Killer Cells of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome Patients

Abstract:

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a disabling multisystemic condition. The pathomechanism of ME/CFS remains unestablished; however, impaired natural killer (NK) cell cytotoxicity is a consistent feature of this condition. Calcium (Ca2+) is crucial for NK cell effector functions.
Growing research recognises Ca2+ signalling dysregulation in ME/CFS patients and implicates transient receptor potential ion channel dysfunction. TRPM7 (melastatin) was recently considered in the pathoaetiology of ME/CFS as it participates in several Ca2+-dependent processes that are central to NK cell cytotoxicity which may be compromised in ME/CFS. TRPM7-dependent Ca2+ influx was assessed in NK cells isolated from n = 9 ME/CFS patients and n = 9 age- and sex-matched healthy controls (HCs) using live cell fluorescent imaging techniques.
Slope (p < 0.05) was significantly reduced in ME/CFS patients compared with HCs following TRPM7 activation. Half-time of maximal response (p < 0.05) and amplitude (p < 0.001) were significantly reduced in the HCs compared with the ME/CFS patients following TRPM7 desensitisation.
Findings from this investigation suggest that TRPM7-dependent Ca2+ influx is reduced with agonism and increased with antagonism in ME/CFS patients relative to the age- and sex-matched HCs. The outcomes reported here potentially reflect TRPM3 dysfunction identified in this condition suggesting that ME/CFS is a TRP ion channelopathy.
Source: Du Preez S, Eaton-Fitch N, Smith PK, Marshall-Gradisnik S. Altered TRPM7-Dependent Calcium Influx in Natural Killer Cells of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome Patients. Biomolecules. 2023; 13(7):1039. https://doi.org/10.3390/biom13071039 https://www.mdpi.com/2218-273X/13/7/1039 (Full text)

Transient receptor potential melastatin 3 dysfunction in post COVID-19 condition and myalgic encephalomyelitis/chronic fatigue syndrome patients

Abstract:

Background: Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a severe multisystemic condition associated with post-infectious onset, impaired natural killer (NK) cell cytotoxicity and impaired ion channel function, namely Transient Receptor Potential Melastatin 3 (TRPM3). Long-term effects of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus has resulted in neurocognitive, immunological, gastrointestinal, and cardiovascular manifestations recently recognised as post coronavirus disease 2019 (COVID-19) condition. The symptomatology of ME/CFS overlaps significantly with post COVID-19; therefore, this research aimed to investigate TRPM3 ion channel function in post COVID-19 condition patients.

Methods: Whole-cell patch-clamp technique was used to measure TRPM3 ion channel activity in isolated NK cells of N = 5 ME/CFS patients, N = 5 post COVID-19 patients, and N = 5 healthy controls (HC). The TRPM3 agonist, pregnenolone sulfate (PregS) was used to activate TRPM3 function, while ononetin was used as a TRPM3 antagonist.

Results: As reported in previous research, PregS-induced TRPM3 currents were significantly reduced in ME/CFS patients compared with HC (p = 0.0048). PregS-induced TRPM3 amplitude was significantly reduced in post COVID-19 condition compared with HC (p = 0.0039). Importantly, no significant difference was reported in ME/CFS patients compared with post COVID-19 condition as PregS-induced TRPM3 currents of post COVID-19 condition patients were similar of ME/CFS patients currents (p > 0.9999). Isolated NK cells from post COVID-19 condition and ME/CFS patients were resistant to ononetin and differed significantly with HC (p < 0.0001).

Conclusion: The results of this investigation suggest that post COVID-19 condition patients may have impaired TRPM3 ion channel function and provide further evidence regarding the similarities between post COVID-19 condition and ME/CFS. Impaired TRPM3 channel activity in post COVID-19 condition patients suggest impaired ion mobilisation which may consequently impede cell function resulting in chronic post-infectious symptoms. Further investigation into TRPM3 function may elucidate the pathomechanism, provide a diagnostic and therapeutic target for post COVID-19 condition patients and commonalities with ME/CFS patients.

Source: Sasso EM, Muraki K, Eaton-Fitch N, Smith P, Lesslar OL, Deed G, Marshall-Gradisnik S. Transient receptor potential melastatin 3 dysfunction in post COVID-19 condition and myalgic encephalomyelitis/chronic fatigue syndrome patients. Mol Med. 2022 Aug 19;28(1):98. doi: 10.1186/s10020-022-00528-y. PMID: 35986236.  https://molmed.biomedcentral.com/articles/10.1186/s10020-022-00528-y (Full text)

Impaired TRPM3-dependent calcium influx and restoration using Naltrexone in natural killer cells of myalgic encephalomyelitis/chronic fatigue syndrome patients

Abstract:

Background: Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a serious disorder of unknown aetiology. While the pathomechanism of ME/CFS remains elusive, reduced natural killer (NK) cell cytotoxic function is a consistent immunological feature. NK cell effector functions rely on long-term sustained calcium (Ca2+) influx. In recent years evidence of transient receptor potential melastatin 3 (TRPM3) dysfunction supports the hypothesis that ME/CFS is potentially an ion channel disorder. Specifically, reports of single nucleotide polymorphisms, low surface expression and impaired function of TRPM3 have been reported in NK cells of ME/CFS patients. It has been reported that mu (µ)-opioid receptor (µOR) agonists, known collectively as opioids, inhibit TRPM3. Naltrexone hydrochloride (NTX), a µOR antagonist, negates the inhibitory action of µOR on TRPM3 function. Importantly, it has recently been reported that NTX restores impaired TRPM3 function in NK cells of ME/CFS patients.

Methods: Live cell immunofluorescent imaging was used to measure TRPM3-dependent Ca2+ influx in NK cells isolated from n = 10 ME/CFS patients and n = 10 age- and sex-matched healthy controls (HC) following modulation with TRPM3-agonist, pregnenolone sulfate (PregS) and TRPM3-antaognist, ononetin. The effect of overnight (24 h) NTX in vitro treatment on TRPM3-dependent Ca2+ influx was determined.

Results: The amplitude (p < 0.0001) and half-time of Ca2+ response (p < 0.0001) was significantly reduced at baseline in NK cells of ME/CFS patients compared with HC. Overnight treatment of NK cells with NTX significantly improved TRPM3-dependent Ca2+ influx in ME/CFS patients. Specifically, there was no significance between HC and ME/CFS patients for half-time response, and the amplitude of Ca2+ influx was significantly increased in ME/CFS patients (p < 0.0001).

Conclusion: TRPM3-dependent Ca2+ influx was restored in ME/CFS patients following overnight treatment of isolated NK cells with NTX in vitro. Collectively, these findings validate that TRPM3 loss of function results in altered Ca2+ influx supporting the growing evidence that ME/CFS is a TRP ion channel disorder and that NTX provides a potential therapeutic intervention for ME/CFS.

Source: Eaton-Fitch N, Du Preez S, Cabanas H, Muraki K, Staines D, Marshall-Gradisnik S. Impaired TRPM3-dependent calcium influx and restoration using Naltrexone in natural killer cells of myalgic encephalomyelitis/chronic fatigue syndrome patients. J Transl Med. 2022 Feb 16;20(1):94. doi: 10.1186/s12967-022-03297-8. PMID: 35172836. https://translational-medicine.biomedcentral.com/articles/10.1186/s12967-022-03297-8  (Full text)

The effect of IL-2 stimulation and treatment of TRPM3 on channel co-localisation with PIP 2 and NK cell function in myalgic encephalomyelitis/chronic fatigue syndrome patients

Abstract:

Background: Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a serious multifactorial disorder. The origin remains ambiguous, however reduced natural killer (NK) cell cytotoxicity is a consistent immunological feature of ME/CFS. Impaired transient receptor potential melastatin 3 (TRPM3), a phosphatidylinositol dependent channel, and impaired calcium mobilisation have been implicated in ME/CFS pathology. This investigation aimed to examine the localisation of TRPM3 at the NK cell plasma membrane and co-localisation with phosphatidylinositol 4,5-bisphosphate (PIP2). The effect of IL-2 priming and treatment using pregnenolone sulfate (PregS) and ononetin on TRPM3 co-localisation and NK cell cytotoxicity in ME/CFS patients and healthy controls (HC) was also investigated.

Methods: NK cells were isolated from 15 ME/CFS patients and 15 age- and sex-matched HC. Immunofluorescent technique was used to determine co-localisation of TRPM3 with the NK cell membrane and with PIP2 of ME/CFS patients and HC. Flow cytometry was used to determine NK cell cytotoxicity. Following IL-2 stimulation and treatment with PregS and ononetin changes in co-localisation and NK cell cytotoxicity were measured.

Results: Overnight treatment of NK cells with PregS and ononetin resulted in reduced co-localisation of TRPM3 with PIP2 and actin in HC. Co-localisation of TRPM3 with PIP2 in NK cells was significantly reduced in ME/CFS patients compared with HC following priming with IL-2. A significant increase in co-localisation of TRPM3 with PIP2 was reported following overnight treatment with ononetin within ME/CFS patients and between groups. Baseline NK cell cytotoxicity was significantly reduced in ME/CFS patients; however, no changes were observed following overnight incubation with IL-2, PregS and ononetin between HC and ME/CFS patients. IL-2 stimulation significantly enhanced NK cell cytotoxicity in HC and ME/CFS patients.

Conclusion: Significant changes in co-localisation suggest PIP2-dependent TRPM3 function may be impaired in ME/CFS patients. Stimulation of NK cells with IL-2 significantly enhanced cytotoxic function in ME/CFS patients demonstrating normal function compared with HC. A crosstalk exists between IL-2 and TRPM3 intracellular signalling pathways which are dependent on Ca2+ influx and PIP2. While IL-2R responds to IL-2 binding in vitro, Ca2+ dysregulation and impaired intracellular signalling pathways impede NK cell function in ME/CFS patients.

Source: Eaton-Fitch N, Cabanas H, du Preez S, Staines D, Marshall-Gradisnik S. The effect of IL-2 stimulation and treatment of TRPM3 on channel co-localisation with PIP2 and NK cell function in myalgic encephalomyelitis/chronic fatigue syndrome patients. J Transl Med. 2021 Jul 15;19(1):306. doi: 10.1186/s12967-021-02974-4. PMID: 34266470.  https://pubmed.ncbi.nlm.nih.gov/34266470/

Potential Therapeutic Benefit of Low Dose Naltrexone in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: Role of Transient Receptor Potential Melastatin 3 Ion Channels in Pathophysiology and Treatment

Abstract:

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a debilitating multi-systemic chronic condition of unknown aetiology classified as an immune dysfunction syndrome and neurological disorder. The discovery of the widely expressed Transient Receptor Potential Melastatin 3 (TRPM3) as a nociceptor channel substantially targeted by certain opioid receptors, and its implication in calcium (Ca2+)-dependent Natural Killer (NK) cell immune functions has raised the possibility that TRPM3 may be pharmacologically targeted to treat characteristic symptoms of ME/CFS. Naltrexone hydrochloride (NTX) acts as an antagonist to the mu (μ)-opioid receptor thus negating its inhibitory function on TRPM3.

Based on the benefits reported by patients on their symptoms, low dose NTX (LDN, 3.0–5.0 mg/day) treatment seems to offer some potential benefit suggesting that its effect may be targeted towards the pathomechanism of ME/CFS. As there is no literature confirming the efficacy of LDN for ME/CFS patients in vitro, this study investigates the potential therapeutic effect of LDN in ME/CFS patients. TRPM3 ion channel activity was measured after modulation with Pregnenolone sulfate (PregS) and ononetin in NK cells on 9 ME/CFS patients taking LDN and 9 age- and sex-matched healthy controls using whole-cell patch-clamp technique.

We report that ME/CFS patients taking LDN have restored TRPM3-like ionic currents in NK cells. Small ionic currents with a typical TRPM3-like outward rectification were measured after application of PregS, a TRPM3-agonist, in NK cells from patients taking LDN. Additionally, PregS-evoked ionic currents through TRPM3 were significantly modulated by ononetin, a TRPM3-antagonist, in NK cells from ME/CFS patients taking LDN.

These data support the hypothesis that LDN may have potential as a treatment for ME/CFS by characterising the underlying regulatory mechanisms of LDN treatment involving TRPM3 and opioid receptors in NK cells. Finally, this study may serve for the repurpose of marketed drugs, as well as support the approval of prospective randomized clinical studies on the role and dose of NTX in treating ME/CFS patients.

Source: Helene Cabanas, Katsuhiko Muraki, Natalie Eaton-Fitch, Donald Ross Staines and Sonya Marshall-Gradisnik. Potential Therapeutic Benefit of Low Dose Naltrexone in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: Role of Transient Receptor Potential Melastatin 3 Ion Channels in Pathophysiology and Treatment. Front. Immunol. | https://doi.org/10.3389/fimmu.2021.687806 https://www.frontiersin.org/articles/10.3389/fimmu.2021.687806/full (Full text)

Validation of impaired Transient Receptor Potential Melastatin 3 ion channel activity in natural killer cells from Chronic Fatigue Syndrome/ Myalgic Encephalomyelitis patients

Abstract:

BACKGROUND: Chronic Fatigue Syndrome/ Myalgic Encephalomyelitis (CFS/ME) is a complex multifactorial disorder of unknown cause having multi-system manifestations. Although the aetiology of CFS/ME remains elusive, immunological dysfunction and more particularly reduced cytotoxic activity in natural killer (NK) cells is the most consistent laboratory finding. The Transient Receptor Potential (TRP) superfamily of cation channels play a pivotal role in the pathophysiology of immune diseases and are therefore potential therapeutic targets. We have previously identified single nucleotide polymorphisms in TRP genes in peripheral NK cells from CFS/ME patients. We have also described biochemical pathway changes and calcium signaling perturbations in NK cells from CFS/ME patients. Notably, we have previously reported a decrease of TRP cation channel subfamily melastatin member 3 (TRPM3) function in NK cells isolated from CFS/ME patients compared with healthy controls after modulation with pregnenolone sulfate and ononetin using a patch-clamp technique. In the present study, we aim to confirm the previous results describing an impaired TRPM3 activity in a new cohort of CFS/ME patients using a whole cell patch-clamp technique after modulation with reversible TRPM3 agonists, pregnenolone sulfate and nifedipine, and an effective TRPM3 antagonist, ononetin. Indeed, no formal research has commented on using pregnenolone sulfate or nifedipine to treat CFS/ME patients while there is evidence that clinicians prescribe calcium channel blockers to improve different symptoms.

METHODS: Whole-cell patch-clamp technique was used to measure TRPM3 activity in isolated NK cells from twelve age- and sex-matched healthy controls and CFS/ME patients, after activation with pregnenolone sulfate and nifedipine and inhibition with ononetin.

RESULTS: We confirmed a significant reduction in amplitude of TRPM3 currents after pregnenolone sulfate stimulation in isolated NK cells from another cohort of CFS/ME patients compared with healthy controls. The pregnenolone sulfate-evoked ionic currents through TRPM3 channels were again significantly modulated by ononetin in isolated NK cells from healthy controls compared with CFS/ME patients. In addition, we used nifedipine, another reversible TRPM3 agonist to support the previous findings and found similar results confirming a significant loss of the TRPM3 channel activity in CFS/ME patients.

CONCLUSIONS: Impaired TRPM3 activity was validated in NK cells isolated from CFS/ME patients using different pharmacological tools and whole-cell patch-clamp technique as the gold standard for ion channel research. This investigation further helps to establish TRPM3 channels as a prognostic marker and/ or a potential therapeutic target for CFS/ME.

Source: Cabanas H, Muraki K, Balinas C, Eaton-Fitch N, Staines D, Marshall-Gradisnik S. Validation of impaired Transient Receptor Potential Melastatin 3 ion channel activity in natural killer cells from Chronic Fatigue Syndrome/ Myalgic Encephalomyelitis patients. Mol Med. 2019 Apr 23;25(1):14. doi: 10.1186/s10020-019-0083-4. https://www.ncbi.nlm.nih.gov/pubmed/31014226