Large-scale investigation confirms TRPM3 ion channel dysfunction in ME/CFS, 2025, Marshall-Gradisnik et al

[John Mac]

Full title: Large-scale investigation confirms TRPM3 ion channel dysfunction in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome

Introduction: Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a chronic disease hallmarked by multiple systemic symptoms, including neurocognitive, respiratory, immunological, gastrointestinal and cardiovascular impairment that worsen following physical and mental exertion. ME/CFS is characterized by an elusive pathomechanism, profound impact on quality of life and an absence of diagnostic tests or evidence-based treatments. Transient Receptor Potential Melastatin 3 (TRPM3) ion channel has been suggested as a potential biomarker and target for therapeutics in people with ME/CFS, supported by a series of publications reporting genetic and protein changes. This study aimed to undertake a multi-site large-scale investigation to determine the consistency of TRPM3 ion channel dysfunction in people with ME/CFS.

Methods: TRPM3 ion channel activity was assessed in two distinct laboratory sites by independent investigators using whole-cell patch-clamp recordings performed in isolated natural killer (NK) cells from 36 ME/CFS participants characterized according to the Canadian Consensus Criteria and 42 healthy controls. The Mann-Whitney U test was used to compare endogenous TRPM3-like currents between cohorts. The effect of location was determined using a covariance analysis, while antagonist sensitivity was determined using Fisher's Exact test.

Results: Electrophysiological experiments revealed a significant reduction in TRPM3 function in NK cells from individuals diagnosed with ME/CFS compared with controls in all parameters analyzed. Importantly, there was no significant effect of the laboratory sites on the results of this investigation, which confirms TRPM3 as a consistent biomarker for ME/CFS.

Conclusion: The current large-sample-size study confirmed previous results regarding TRPM3 ion channel dysfunction in NK cells in ME/CFS, demonstrating involvement of TRPM3 in the pathomechanism of this condition. Therefore, this multiple-site investigation offers strong evidence demonstrating TRPM3 as a potential biomarker for the diagnosis of ME/CFS, given the accumulating evidence.

Frontiers | Large-scale investigation confirms TRPM3 ion channel dysfunction in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome

Introduction: Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a chronic disease hallmarked by multiple systemic symptoms, including neurocogni...

www.frontiersin.org

 

[forestglip]

Relevant tags with previous papers by this group and others: TRPM3, TRPM

 

[Trish]

Is only the abstract available. I'll wait to see how much overlap there is between pwME and health controls before I get interested. They are claiming it's a biomarker, which to me implies clear separation between groups.

 

[Sly Saint]

Relevant tags with previous papers by this group and others: TRPM3, TRPM

all tags are at the top of the thread. All papers by this group are under tag "marshall-gradisnik".

 

[Trish]

I have no idea how difficult or expensive the test is, but boasting of a study being
'a multi-site large-scale investigation' when they only tested 36 pwME in 2 labs seems somewhat overblown.

 

[DMissa]

I have no idea how difficult or expensive the test is, but boasting of a study being
'a multi-site large-scale investigation' when they only tested 36 pwME in 2 labs seems somewhat overblown.

Just to address the question of the method, patch clamping is notoriously difficult

 

[ScoutB]

The fact that this was found in 2 labs does seem exciting -- sort of like a partial replication I guess? Depending on how much their tools and inputs overlapped between labs. Impatient to see the full paper.

 

[V.R.T.]

Just to address the question of the method, patch clamping is notoriously difficult

Would this count as a 'large scale investigation' as far as patch clamping goes then?

 

[DMissa]

Would this count as a 'large scale investigation' as far as patch clamping goes then?

I have no idea what is typical when using this technique to test samples from people (whether this is a thing that anybody else does in other disease contexts, I also don’t know)

 

[V.R.T.]

Does anyone knowledgable have any opinions on whether this paper in fact strengthens the groups previous findings or whether it repeats the problems with the previous papers at a larger scale?

 

[DMissa]

Does anyone knowledgable have any opinions on whether this paper in fact strengthens the groups previous findings or whether it repeats the problems with the previous papers at a larger scale?

Have to wait for the paper to be out for the smarter forum members to scrutinise results

(To be clear, I mean smarter than me)

 

[V.R.T.]

Have to wait for the paper to be out for the smarter forum members to scrutinise results

Oh, it's just an abstract! I hadn't noticed.

 

[Alinda]

Frontiers | Large-scale investigation confirms TRPM3 ion channel dysfunction in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome

IntroductionMyalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a chronic disease hallmarked by multiple systemic symptoms, such as neurocognitive...

www.frontiersin.org

 

[Kitty]

I don't know anything about TRPM3 or lab techniques, but that's a very striking graph.

Figure 1. TRPM3 ion channel activity in NK cells from HC and ME/CFS. (A–C) Example of a recording on an NK cell from HC. (A) A representative time-series of a current at +100 mV and −100 mV. (B)Representative I–V curve showing results before and at the end of PregS stimulation. (C). Representative I–V curve measured at the conclusion of PregS stimulation and following ononetin exposure. (D–F) Example of a recording on an NK cell from a person diagnosed with ME/CFS. D. A representative time-series of a current amplitude at +100 mV and −100 mV. (E) Representative I–V curve showing results before and at the end of PregS stimulation. (F)Representative I–V curve measured at the conclusion of PregS stimulation and following ononetin exposure. HC, healthy control; ME/CFS, Myalgic Encephalomyelitis/Chronic Fatigue Syndrome; NK, natural killer; PregS, pregnenolone sulfate.

 

[Jonathan Edwards]

I don't know anything about TRPM3 or lab techniques, but that's a very striking graph.

It's only one sample each isn't it?

 

[hotblack]

I’m obviously in no position to comment on validity of any of this. But if it is, this seems like it would be interesting particular in the context of other studies which have shown possible calcium and ion channel involvement (including the precision life analysis).

A few other questions it raises for me. Could this be present beyond NK cells, in other cell populations? How does this fit in with other studies of electrophysiological properties of cells? Where on the chain of cause and effect would this be?

 

[hotblack]

It's only one sample each isn't it?

Oh yeah “Example of a recording on an NK cell from HC” and “Example of a recording on an NK cell from a person diagnosed with ME/CFS”… that does rather spoil things.

Figure 2 seems to aggregate results

 

[StellariaGraminea]

It's only one sample each isn't it?

Is the graph only an example rather than representative? I could be misunderstanding, but thought I read somewhere there were multiple samples of NK cells checked? This is like reading a different language for me so please ignore if I'm not making sense.

"The statistical analysis includes 552 whole-cell patch-clamp recordings. Regarding PregS stimulation, 248 recordings from NK cells from ME/CFS and 304 from HC were taken. Given that the viability of NK cells during perfusion protocols with pharmacological agents or current was unstable during the second half of recording, the number of ononetin analyses included 452 recordings from 195 ME/CFS and 257 HC NK cells. NCNED processed 33 HC and 26 ME/CFS samples, while UWA processed 9 samples from HC and 10 from ME/CFS patients."

 

[Jonathan Edwards]

Is the graph only an example rather than representative?

I think it is just one example and presumably the most impressive one of each. I would not allow a figure like that to be published if I were the referee.

 

[forestglip]

Like another study from this group that was posted here, it looks like the p-values are artificially low due to pseudoreplication. I'll just quote the last time I said it, since it's the same issue, just with the sample size changed:

I think they may have used non-independent samples which artificially decreased the p-values, though. There were 9 people per group, but they used multiple cells per person, which are expected to be correlated to each other. Technically, you could get a p value as low as you want by using a very high number of cells from each person. [Edit: More accurately: greatly increase the chances of a low p value.]

In the electrophysiological experiments, we included nine participants in each group and analyzed recordings from 61, 65, and 63 independent cells for PregS effects from long COVID, HC, and long COVID receiving LDN groups, respectively. In addition, to assess ononetin effects in the presence of PregS, 52 independent recordings from NK cells in the long COVID group, 53 in NK cells from HC, and 53 recordings from NK cells in the long COVID group receiving LDN.

I don't see any indication in the paper's description of methods that they accounted for correlated samples.

See explanation of the issue of pseudoreplication here: Pseudoreplication in physiology: More means less (Eisner, 2021, Journal of General Physiology)

Edit: This is regarding the p values they reported that are very low:

As reported in earlier studies, we confirmed a reduction in ononetin amplitude (p = 0.0021) and the number of cells sensitive to ononetin (p < 0.0001) when compared to the HC and long COVID group. In contrast, NK cells from the long COVID group receiving LDN had a significant elevation in amplitude (p = 0.0005) and sensitivity (p < 0.0001) to ononetin compared with the long COVID group.