A possible role for mitochondrial-derived peptides humanin and MOTS-c in patients with Q fever fatigue syndrome and chronic fatigue syndrome. — ME/CFS Atlas
A possible role for mitochondrial-derived peptides humanin and MOTS-c in patients with Q fever fatigue syndrome and chronic fatigue syndrome.
Raijmakers, Ruud P H, Jansen, Anne F M, Keijmel, Stephan P et al. · Journal of translational medicine · 2019 · DOI
Quick Summary
This study looked at a specific type of protein fragment called humanin that is made inside cells' energy factories (mitochondria). Researchers found that people with ME/CFS and Q fever fatigue syndrome had lower levels of this protein compared to healthy people. The findings suggest that problems with how these protein fragments are made may be involved in causing fatigue in these conditions.
Why It Matters
This research identifies a potential biological mechanism shared between ME/CFS and QFS, pointing to mitochondrial dysfunction as a common pathway. Understanding MDP dysregulation could lead to new diagnostic biomarkers or therapeutic targets for ME/CFS patients.
Observed Findings
MT-RNR2 (humanin) was significantly downregulated in CFS (−5.2 log2-fold-change, P=3.49×10⁻¹¹), QFS (−4.8 log2-fold-change, P=2.19×10⁻⁹), and Q fever seropositive controls (−3.7 log2-fold-change, P=1.78×10⁻⁶) compared to healthy controls.
MT-RNR1 (MOTS-c) was significantly downregulated in CFS (−4.4 log2-fold-change, P=2.71×10⁻⁹), QFS (−4.9 log2-fold-change, P=4.69×10⁻⁸), and Q fever seropositive controls (−3.2 log2-fold-change, P=1.12×10⁻⁵) compared to healthy controls.
Median serum humanin concentration was reduced in CFS patients (364 pg/mL, IQR 316–387) and QFS patients (371 pg/mL, IQR 325–384) compared to healthy controls.
Reduced MDP expression was observed even in asymptomatic Q fever seropositive individuals (354 pg/mL humanin), suggesting a persistent transcriptomic change.
Inferred Conclusions
Mitochondrial-derived peptides humanin and MOTS-c are downregulated in both CFS and QFS, suggesting a shared pathophysiological mechanism.
Low-grade inflammation and mitochondrial dysfunction may be relevant to fatigue pathogenesis in both post-infectious and idiopathic chronic fatigue syndromes.
MDPs warrant investigation as potential biomarkers and therapeutic targets in ME/CFS.
Remaining Questions
What are the functional consequences of reduced humanin and MOTS-c levels, and do they directly contribute to fatigue or other CFS/QFS symptoms?
What This Study Does Not Prove
This study does not prove that low humanin levels *cause* ME/CFS or QFS—it only shows an association. The study cannot determine whether reduced MDP expression is a primary cause, a consequence of the illness, or merely a marker of mitochondrial stress. Functional studies are needed to establish whether restoring humanin levels would improve symptoms.
Tags
Symptom:Fatigue
Biomarker:Gene ExpressionBlood Biomarker
Phenotype:Infection-Triggered
Method Flag:Weak Case DefinitionSmall SampleExploratory Only
About the PEM badge: “PEM required” means post-exertional malaise was an explicit required diagnostic criterion for participant inclusion in this study — not that PEM was studied, observed, or discussed. Studies using criteria that do not require PEM (e.g. Fukuda, Oxford) are tagged “PEM not required”. How the atlas works →