MOTS-C

AIMS: Hyperoxia-induced oxidative stress is a primary cause of neonatal injury. Neonatal heart shows a particular susceptibility to hyperoxic toxicity, yet mechanisms and effective therapeutic strategies remain limited. Oxeiptosis is a ROS-specific programmed cell death. Mitochondrial-derived peptide MOTS-c possesses well-known anti-oxidative effect. This study investigated the cardio-protective role of MOTS-c in hyperoxia exposed neonatal mice and its mechanism. MAIN METHODS: Neonatal mice exposed hyperoxia (85% O 2 ) were used to establish the hyperoxic cardiac injury model. Additionally, the rat cardiomyocyte cell line H9C2 were subjected to hyperoxic conditions as an in vitro model. Serum MOTS-c content was measured using enzyme-linked immunosorbent assay. Hematoxylin and eosin staining, Real-time PCR, Western blotting, immunohistochemistry, and immunofluorescence techniques were employed to evaluate the effects of MOTS-c on hyperoxia-induced cardiac insufficiency. KEY FINDINGS: We found that hyperoxia exposure in neonatal mice led to significant cardiac hypertrophy, fibrosis, and dysfunction, concomitant with decreased serum MOTS-c content. Administration of MOTS-c markedly ameliorated these pathological changes and restored cardiac function. In vitro and in vivo experiments revealed that hyperoxia triggers oxidative stress and oxeiptosis via activating KEAP1-PGAM5-AIFM1 axis, and MOTS-c inhibited oxeiptosis. Mechanistically, MOTS-c could potentially interact with KEAP1, thereby maintaining the KEAP1-PGAM5 interaction, and inhibiting the downstream nuclear translocation of AIFM1. Notably, KEAP1 overexpression abrogated the protective effects of MOTS-c, confirming KEAP1 as a critical target of MOTS-c in hyperoxia-induced cardiac injury. SIGNIFICANCE: MOTS-c attenuates hyperoxic cardiac injury by inhibiting KEAP1-mediated oxeiptosis, highlighting its potential as a novel therapeutic agent for neonatal cardiomyopathy.

Mitochondrial function is critical for spermatogenesis and male fertility. MOTS-c, a mitochondrially encoded regulatory peptide, has recently been reported to effectively protect testicular spermatogenesis in mice, but its specific role and mechanism remain unclear. This study first demonstrated that MOTS-c levels were significantly reduced in the serum of patients with oligoasthenozoospermia, and these levels correlated with semen quality parameters. Spermatogenic dysfunction, including decreased sperm concentration, disrupted seminiferous tubule architecture, and a reduction in spermatogonia, was induced by mechanical stress through microgravity model. Notably, exogenous MOTS-c ameliorated spermatogenic impairment by suppressing oxidative stress and ferroptosis induced by mechanical stress. Solute Carrier Family 7 Member 11 (SLC7A11), a key molecule in ferroptosis, was identified as a target of MOTS-c. Moreover, loss- and gain-of-function studies showed that SLC7A11 inhibited ferroptosis and oxidative stress and promoted spermatogonia proliferation. Furthermore, MOTS-c enhanced the protection against spermatogenic impairment by increasing SLC7A11 levels under mechanical stress. Collectively, this study elucidates the crucial role of MOTS-c in protecting spermatogenesis by antagonizing ferroptosis, providing a theoretical foundation for its potential therapeutic use in male infertility associated with spermatogenic defects.

BACKGROUND: Mitochondrial dysfunction contributes substantially to myocardial ischemia-reperfusion (IR) injury through impaired bioenergetics, oxidative stress, and disruption of mitochondrial homeostasis. MOTS-c, a mitochondrial-derived peptide encoded within the 12 S rRNA region of mtDNA, has been implicated in metabolic stress adaptation, although its role in myocardial IR injury remains incompletely understood. METHODS AND RESULTS: Isolated female Wistar rat hearts (n = 6/group) were subjected to 30 min global ischemia followed by 60 min reperfusion using the Langendorff perfusion model. MOTS-c (53 µM) was administered either before ischemia or at reperfusion onset. Cardiac mechanical function, myocardial injury, mitochondrial bioenergetics, oxidative stress, mtDNA copy number, and mitochondrial regulatory gene expression were evaluated in subsarcolemmal and interfibrillar mitochondrial populations. IR significantly impaired cardiac mechanical recovery, increased oxidative stress, reduced electron transport chain and dehydrogenase enzyme activities, disrupted mitochondrial membrane potential, and decreased mtDNA copy number and expression of mitochondrial regulatory genes. MOTS-c treatment improved post-ischemic mechanical recovery, attenuated oxidative stress, partially preserved mitochondrial enzyme activities and membrane potential, and mitigated reductions in mtDNA copy number and mitochondrial gene expression. Protective effects were observed in both mitochondrial subpopulations, although responses varied across parameters. CONCLUSIONS: MOTS-c treatment was associated with preservation of mitochondrial functional integrity and improved cardiac recovery following IR injury. These findings support a potential role for mitochondrial-derived peptides in modulating cardiac mitochondrial stress responses during ischemia-reperfusion injury, although the underlying signaling mechanisms require further validation.

BACKGROUND: Cancer cachexia is a multifactorial metabolic syndrome marked by progressive skeletal muscle loss, reduced function, and increased mortality. Mitochondrial dysfunction is a key driver of this phenotype. MOTS-c, a mitochondrial-derived peptide that regulates metabolic homeostasis and mimics exercise signaling, may counteract cachexia, but its role remains largely unexplored, and human studies using MOTS-c in subjects with cancer cachexia are needed. METHODS: Differentiated myotubes were treated with MOTS-c (50 μM) to assess intracellular signaling. In vivo , male mice were inoculated with Colon-26 (C26) carcinoma cells and treated daily with MOTS-c (15 mg/kg/2x Day, i.p.) or vehicle. Body weight was monitored daily. At euthanasia, organ and skeletal muscle masses were measured. Molecular analyses focused on FOXO signaling, atrogene expression (MuRF1, Atrogin-1), and mitochondrial biogenesis markers, including PGC-1α. RESULTS: In vitro , MOTS-c increased PGC-1α mRNA (+84.6%) and AMPK phosphorylation (+103.1%). C26 tumor-bearing mice exhibited significant systemic wasting (~9% body weight loss). Although MOTS-c did not prevent total body weight or fat loss, it significantly preserved skeletal muscle mass, rescuing quadriceps weight (+12% vs. C26 vehicle; p < 0.05) and trending toward protection of gastrocnemius mass and EDL function. Cachexia-induced upregulation of Atrogin-1 (+8.6-fold) and MuRF1 (+16-fold) was attenuated by MOTS-c, accompanied by increased inhibitory pFOXO1 (+80%), reduced pFOXO3a (-39%), and partial restoration of PGC-1α protein (+143%). CONCLUSION: Our findings demonstrate that MOTS-c partially protects against skeletal muscle loss in C26 cachexia by modulating FOXO-driven catabolic signaling and promoting mitochondrial biogenesis, supporting its therapeutic potential in cancer cachexia.

Background : Hashimoto's thyroiditis (HT) is a common autoimmune disorder characterized by chronic inflammation and metabolic alterations. Mitochondria-derived peptides (MDPs), particularly mitochondrial open-reading frame of the 12S rRNA-c (MOTS-c), have emerged as key regulators of cellular metabolism, insulin sensitivity, oxidative stress, and inflammatory responses. This study aimed to investigate the association between circulating MOTS-c levels and HT and to explore its potential role in thyroid autoimmunity and metabolic regulation. Methods : In this cross-sectional study, patients diagnosed with HT ( n : 90) were compared with age- and sex-matched healthy controls ( n : 90). Results : A total of 180 participants were included, comprising 90 patients with HT and 90 age- and sex-matched healthy controls. Circulating MOTS-c levels were significantly lower in patients with HT compared to controls ( p < 0.001). MOTS-c levels demonstrated significant inverse correlations with body mass index, fasting glucose, HbA1c, HOMA-IR, thyroid-stimulating hormone, C-reactive protein, and thyroid autoantibody levels (all p < 0.05). In subgroup analyses, these associations remained significant within the HT cohort, particularly for HOMA-IR and thyroid autoantibodies. Multivariable regression analysis identified HT (β = -30.04, p < 0.001) and HOMA-IR (β = -0.85, p < 0.001) as independent determinants of reduced circulating MOTS-c levels. Levothyroxine (LT4) use was not associated with significant differences in MOTS-c concentrations. Conclusions : Circulating MOTS-c levels are markedly reduced in patients with HT and are independently associated with insulin resistance and autoimmune burden. These findings suggest that impaired mitochondrial signaling may play a role in the pathophysiology of thyroid autoimmunity and highlight MOTS-c as a promising biomarker linking metabolic dysfunction and immune dysregulation.

PURPOSE: Oxidative stress (OS) and endothelial dysfunction are major drivers of cardiovascular disease (CVD) in peritoneal dialysis (PD). MOTS-c, a mitochondria-derived peptide, is emerging as a key regulator of skeletal muscle health, metabolic homeostasis, and vascular function, yet its role in the uremic environment remains unexplored. We investigated the relationship between MOTS-c levels, OS markers, and vascular stiffness in PD patients. METHODS: This pilot, clinical study included 32 stable PD patients (mean age 60.7 ± 1.2 years, 62.5% male). MOTS-c levels were quantified in serum (sMOTS-c), urine (uMOTS-c), and peritoneal dialysate (dMOTS-c). Systemic oxidative status was assessed via plasma Advanced Oxidation Protein Products (AOPPs). Vascular function was evaluated by carotid-femoral Pulse Wave Velocity (PWV), and left ventricular systolic function was assessed echocardiographically. RESULTS: Urinary MOTS-c (uMOTS-c) levels were inversely correlated with serum AOPPs (R = - 0.592, p = 0.012) and a positive association with PWV (R = 0.708, p = 0.001) and left ventricular systolic function (R = 0.440, p = 0.04). Conversely, dialysate MOTS-c (dMOTS-c) were strongly and inversely correlated with PWV (R = - 0.717, p = 0.019) as well as systolic and diastolic blood pressure (R = -0.5, p < 0.01). CONCLUSION: Ηigher urinary MOTS-c was linked to lower systemic oxidative stress, suggesting a potential protective role, and associated with greater arterial stiffness, potentially reflecting a compensatory response to vascular injury. In contrast, higher peritoneal MOTS-c levels were associated with an improved vascular profile. These findings suggest a novel 'Mitochondrial-Vascular Axis' in uremia, highlighting MOTS-c as a potential biomarker.

Background: Atrial fibrillation (AF) is a common clinical arrhythmia associated with mitochondrial dysfunction, oxidative stress, and atrial fibrosis. Mitochondrial-derived peptides (MDPs), including humanin (HN) and MOTS-c, exhibit cytoprotective properties, but their role in AF remains largely unknown. Objective: This study aimed to investigate the expression of HN and MOTS-c in AF patients and to evaluate their therapeutic potential and underlying mechanisms in an AngII-induced mouse model and primary cardiac cells. Methods: HN and MOTS-c expression in human atrial tissues was analyzed using public GEO data, immunohistochemistry, and immunofluorescence. Plasma levels were measured in a matched cohort (39 AF patients, 39 sinus rhythm controls). Murine AF models (male C57BL/6J mice, n = 36) and primary rat cardiomyocytes and fibroblasts were exposed to angiotensin II (AngII) with or without treatment with HNG (an HN analogue) or MOTS-c. Results: HN and MOTS-c were significantly downregulated in human AF atrial tissue, and their levels inversely correlated with fibrosis extent. Plasma MOTS-c was decreased in AF patients and inversely correlated with NT-proBNP. In vivo, HNG or MOTS-c treatment reduced AF inducibility and attenuated AngII-induced atrial fibrosis and hypertrophy. Peptide treatment was associated with improved mitochondrial ultrastructure, reduced mitochondrial fission proteins (Drp1, Fis1), and lower pro-inflammatory cytokines (IL-1β, IL-6) in mouse atria. In primary cardiomyocytes, both peptides mitigated AngII-induced oxidative stress. In fibroblasts, they directly inhibited AngII-induced activation, proliferation, and migration. Exploratory RNA-seq suggested that HNG predominantly affects cell adhesion pathways, while MOTS-c acts on metabolic processes. Conclusions: Downregulation of HN and MOTS-c in human AF is associated with disease severity. In murine models, HNG or MOTS-c administration attenuates atrial fibrosis and mitochondrial dysfunction and reduces AF inducibility. These findings suggest that MDPs may represent a novel therapeutic avenue for AF, although further validation with larger cohorts and mechanistic studies are required.

OBJECTIVE: MOTS-c is a mitochondria-derived peptide associated with reduced insulin resistance and obesity. The m.1382A>C polymorphism of the MOTS-c gene is linked to an increased risk of type 2 diabetes in men. However, no studies have explored the relationship between this polymorphism and MOTS-c levels in adolescents with polycystic ovary syndrome (PCOS). This study aimed to investigate the differences in MOTS-c levels between adolescents diagnosed with PCOS and those without PCOS, as well as the associations with metabolic parameters. The association between the MOTS-c gene polymorphism and serum MOTS-c levels in adolescents with PCOS was also evaluated. SUBJECTS AND METHODS: Adolescents aged 12-18 diagnosed with PCOS were recruited based on irregular menstrual cycles and clinical/biochemical hyperandrogenism, excluding other conditions. The control group consisted of adolescents with regular menstruation. Serum MOTS-c levels were measured using ELISA, and the m.1382A>C polymorphism was analyzed by sequencing. RESULTS: The study included 121 adolescents with PCOS and 125 healthy controls. The mean serum MOTS-c levels in the PCOS group were higher than in the control group; however, this difference did not reach statistical significance (p = 0.059). There was no significant association between MOTS-c levels and anthropometric or metabolic parameters within the PCOS group (p > 0.05). All participants had the wild-type (A/A) genotype for the m.1382A>C polymorphism. RESULTS: indicate that the MOTS-c gene (m.1382A>C) polymorphism shows no significant association with PCOS, and serum MOTS-c levels are comparable between individuals with PCOS and healthy controls, suggesting that MOTS-c may have a minor involvement in the pathophysiology of PCOS.

Mitochondria form highly dynamic and interconnected networks that continuously communicate with the cytoplasm and the nucleus to maintain cellular homeostasis and coordinate adaptive responses to stress. This bidirectional communication, known as mito-nuclear crosstalk, is essential for regulating metabolism, redox balance, immune activation, and cell fate decisions. While retrograde signalling has traditionally been viewed as a consequence of metabolic or oxidative perturbations, mounting evidence positions mitochondrial DNA (mtDNA) as a central and active regulator of these signalling pathways. Beyond encoding essential subunits of the electron transport chain, mtDNA functions as a signalling hub that conveys information about mitochondrial functional status to the nucleus. Perturbations in mtDNA integrity, copy number, or expression initiate retrograde responses through metabolic rewiring, alterations in redox and calcium signalling, and activation of stress-responsive transcriptional programmes. In addition, mtDNA-derived products, including mitochondrial-derived non-coding RNAs (mt-ncRNAs) and mitochondrial-derived peptides (MDPs), have emerged as key messengers that shuttle between cellular compartments, reshape nuclear gene expression, and influence cellular and systemic responses to stress. These molecules participate in diverse processes, ranging from mitochondrial biogenesis and quality control to innate immune activation and epigenetic regulation. This review synthesises current knowledge on mtDNA-driven retrograde signalling, highlighting both classical and emerging mechanisms by which the mitochondrial genome communicates with the nucleus. We discuss how mtDNA instability, defective repair, and altered mitochondrial dynamics trigger signalling cascades involving metabolic sensors, calcium fluxes, and innate immune pathways. We further examine the growing evidence supporting regulatory roles for mt-ncRNAs, including small RNAs, long non-coding RNAs, double-stranded RNAs, and circular RNAs, as well as MDPs such as Humanin, SHLPs, and MOTS-c, in coordinating adaptive nuclear responses. By integrating these diverse signalling modalities, this review highlights mtDNA as an integral and active signalling platform that coordinates mitochondrial stress sensing with nuclear adaptive responses.

The mitochondrial-derived peptide MOTS-c regulates metabolic and cellular stress responses, but its dose-response profile and direct cardioprotective mechanisms in myocardial ischemia-reperfusion injury (MIRI) remain undefined. This proof-of-concept study aimed to identify the optimal cardioprotective dose of exogenous MOTS-c and delineate its multi-pathway mechanisms using an ex vivo rat heart IR model with in silico support. Isolated Langendorff-perfused rat hearts underwent 30-min global ischemia and 60-min reperfusion with or without MOTS-c (0.25-0.7 mg/kg) delivered via Krebs-Henseleit buffer during the first 10 min of reperfusion. Hemodynamics, infarct size (TTC), oxidative stress markers, inflammation, and apoptotic gene expression were quantified. Peptide-protein interactions with survival pathways were predicted computationally. MOTS-c at 0.5 mg per kg conferred maximal protection, producing a 73% reduction in infarct size compared with ischemia-reperfusion alone, improving heart rate, left ventricular developed pressure, and rate-pressure product, and lowering end-diastolic pressure. Lactate dehydrogenase release decreased by 65%. Antioxidant defenses improved with increased superoxide dismutase, catalase, and glutathione redox ratio, along with reduced lipid peroxidation. Myeloperoxidase activity normalized, pro-apoptotic genes including caspase 3, caspase 7, caspase 9, BAX, and PARP were downregulated, while cytoprotective genes including BCL2, GPX4, and FOXO were increased. Molecular docking demonstrated high-affinity interactions of MOTS-c with MAPK, mTOR, AMPK, NRF2, PI3K, and caspase 3. This ex vivo study identifies 0.5 mg/kg as the optimal dose within the tested range, producing coordinated anti-apoptotic, antioxidant, and anti-inflammatory effects. Although the isolated heart model isolates direct myocardial actions, the lack of systemic influences and limited dose range necessitate broader dosing and pharmacokinetic studies before translational application.

Oxidative stress play key roles in the pathogenesis of bronchopulmonary dysplasia (BPD). MOTS-c is a mitochondria-derived peptide containing 16 amino acids that is reported to be involved in the treatment of oxidative stress-related diseases. However, whether MOTS-c functions on hyperoxia-induced BPD remains unknown. The purpose of this study was to investigate the potential therapeutic effect and mechanism of MOTS-c on hyperoxia-induced BPD. Here, hyperoxia (70% O 2 ) was used to mimic the murine BPD model. We found that MOTS-c content was reduced in hyperoxia-induced BPD mice. Exogenous MOTS-c supplementation alleviated growth retardation, attenuated alveolar simplification, and pulmonary vascular abnormalities in hyperoxia-induced BPD mice. Besides, MOTS-c supplement increased cell viability, inhibited cell death and promoted tube formation in hyperoxia-stimulated HUVECs. Moreover, MOTS-c administration significantly inhibited inflammation and oxidative stress both in vivo and in vitro. In addition, the beneficial effect of MOTS-c was Nrf2 dependent, since the anti-inflammation, anti-oxidative and pro-angiogenic effects of MOTS-c were offset in ML385 (a specific Nrf2 inhibitor) treated HUVECs or in Nrf2 deficiency mice. In conclusion, MOTS-c protects against hyperoxia-induced lung alveolar simplification and abnormal angiogenesis in an Nrf2-dependent manner. MOTS-c emerges as a potential anti-oxidant therapeutic agent to treat hyperoxia-induced BPD.

Mitochondrial-derived peptides are a small class of regulatory peptides encoded by short open reading frames in mitochondrial DNA. One such peptide, mitochondrial open reading frame of the 12S rRNA-c (MOTS-c), has been shown to exert numerous beneficial effects on whole-cell and systemic metabolic parameters when administered exogenously. However, potential MOTS-c-mediated effects on mitochondrial bioenergetics have been largely overlooked. Therefore, the primary aim of the present study was to elucidate whether and, if so, how MOTS-c regulates skeletal muscle (SkM) mitochondrial function. We demonstrate, using two distinct transgenic mouse strains, that administration of MOTS-c augments muscle mitochondrial bioenergetic performance through reliance on both the transcriptional coactivator, Peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PGC-1α), and cellular energy-sensing kinase, 5' adenosine monophosphate-activated protein kinase (AMPK). These effects seem to be exerted without apparent impact on mitochondrial respiratory protein content, alluding to intrinsic mitochondrial changes rather than changes in volume. Furthermore, MOTS-c treatment lowers mitochondrial reactive oxygen species (ROS) emission and ROS-related protein damage indicating substantial alleviation of cellular oxidative stress. RNA-sequence data reveal the effects of MOTS-c treatment to potentially be exerted subtly across a number of mitochondrial parameters such as redox handling, mitochondrial integrity and OXPHOS efficiency, jointly indicating a mechanistic basis for the observed functional improvements in mitochondrial bioenergetics. Despite increased interstitial MOTS-c levels no change was observed in the arterio-venous difference during one-legged knee extensor exercise in humans. This suggests that SkM may not be the source of circulating MOTS-c in response to exercise.

BACKGROUND: This study investigated the effects of dietary graviola (Annona muricata L.) oil extract (GOE) (supplemented at 200, 400, and 600 mg/kg) on the growth performance and circadian rhythm profiles of adipokine, cardiac, and mitochondrial function biomarkers in 48 male Anatolian Merino lambs (2.5 months old). METHODS: Lambs were assigned to a control group (G0) or supplementation groups (G200, G400, G600 mg/kg) for a 60-day trial (70 days total). The study was conducted under a 12-h light/12-h dark cycle to ensure controlled environmental conditions. To analyze circadian profiles, blood samples were collected on days 0, 15, 30, 45, and 60 at four time points (07:00, 13:00, 19:00, and 01:00). Serum levels of Apelin, cTnI, BMAL1, MOTS-c, and BMCP1 were measured by ELISA. Data were analyzed using GLM Multivariate analysis (p < 0.05). RESULTS: Key findings showed the G400 dose resulted in the most effective linear increase in live weight and live weight gain by day 60, and had a significant overall effect on live weight (p < 0.05). The G200 dose significantly improved the feed conversion ratio (p < 0.05), while feed consumption was unaffected (p > 0.05). Regarding biomarkers on day 60, the G400 dose effectively modulated BMAL1, MOTS-c, and BMCP1 (peak at 19:00). The G600 dose yielded the best results for Apelin (peak at 19:00) and cTnI (peaks at 13:00 and 07:00). CONCLUSIONS: In conclusion, GOE at a dose of 400 mg/kg (G400) not only optimizes fattening performance in Anatolian Merino lambs but also supports metabolic homeostasis by modulating adipokine levels, cardiac function, and mitochondrial biogenesis processes in a manner consistent with the circadian rhythm. These findings demonstrate that the G400 dose is a safe and effective phytogenic strategy for improving animal health and production efficiency.

BACKGROUND: Sepsis-associated encephalopathy (SAE) is a serious complication of sepsis, increasing short-term and long-term mortality. It involves neuroinflammation, neuronal damage, and blood-brain barrier (BBB) disruption. MOTS-c, a mitochondrion-derived peptide, exerts neuroprotective effects by modulating inflammatory responses and cellular functions. This study explored the protective effects of MOTS-c against brain injury in mice with LPS-induced sepsis. METHODS: A mouse model of sepsis was established via intraperitoneal injection of LPS. The mice were divided into four groups: Control, Control + MOTS-c, LPS, and LPS + MOTS-c groups. The mice in the latter two groups received MOTS-c (20 mg/kg) four hours before model establishment. Survival rates and the murine sepsis score (MSS) were recorded. H&E staining, ELISA, Evans blue staining, brain water content detremination, immunofluorescence staining, western blotting, and qPCR were performed to assess brain tissue damage, inflammation, BBB permeability, and BBB-related protein expression. RESULTS: MOTS-c treatment increased the survival rate, decreased the MSS score, alleviated brain tissue damage, downregulated the expression of inflammatory factors, reversed the increase in BBB permeability, upregulated the expression of BBB-related proteins and CD31/PDGFRβ, decreased the expression of GFAP/Iba-1/MMP-9, and increased the expression of neurotrophic factors in septic mice. CONCLUSION: MOTS-c effectively reduced mortality rates and the MSS, attenuated neuroinflammatory responses, mitigated increase in BBB permeability, promoted neurotrophic factor production, and protecting against brain injury in mice with LPS-induced sepsis.

Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by impaired social interaction and repetitive behaviors, with currently limited therapeutic options. Oxidative stress is suggested as significant in ASD pathophysiology, making antioxidant strategies a promising therapeutic direction. Exercise reduces oxidative stress, alleviates ASD symptoms, and increases tetrahydrobiopterin (BH4) and brain-derived neurotrophic factor (BDNF) levels through AMP-activated protein kinase (AMPK) activation. MOTS-c, a mitochondrial-derived peptide acting through AMPK, mimics the effects of exercise but reportedly does not cross the blood-brain barrier (BBB). Considering the challenges in exercise adherence in ASD, our study hypothesizes that MOTS-c could increase circulating BH4 and BDNF, both of which are BBB-permeable, and alleviate oxidative stress and ASD symptoms. To evaluate this hypothesis, we investigated the effects of MOTS-c in the valproic acid-induced rat model of autism. Pregnant Sprague-Dawley rats received intraperitoneal 500 mg/kg valproic acid or saline on embryonic day 12. Female and male offspring were treated with 0.5 mg/kg/day MOTS-c or saline intraperitoneally from postnatal days 21 to 46. Following behavioral testing, animals were sacrificed, and histological and biochemical analyses were performed. Valproic acid exposure led to impaired sociability, repetitive behaviors, anxiety, cerebellar Purkinje cell loss, and increased oxidative stress and neuronal damage in the prefrontal cortex. These alterations were reversed by MOTS-c, except for anxiety and neocortical damage. No significant changes in plasma BH4 or BDNF levels were detected. Through its neuroprotective and antioxidant effects independent of BH4 and BDNF, MOTS-c may alleviate autism-like behaviors, suggesting its potential as a therapeutic candidate for ASD.

UNLABELLED: Polycystic ovary syndrome (PCOS) is characterized by insulin resistance and metabolic dysfunction. Mitochondrial-derived peptides (MDPs), including MOTS-c, regulate glucose homeostasis and skeletal muscle metabolism. Whether MOTS-c expression is altered in PCOS across different physiological compartments remains unknown. The aim was to assess circulating and skeletal muscle MOTS-c levels in women with PCOS and to examine their associations with metabolic and hormonal parameters. Forty women with PCOS and 40 age- and BMI-matched healthy controls underwent clinical, biochemical, and hormonal phenotyping. Serum MOTS-c concentrations were quantified by ELISA. In a representative subgroup, skeletal muscle MOTS-c expression was assessed in vastus lateralis biopsy specimens using Western blotting. Women with PCOS exhibited lower circulating MOTS-c concentrations compared with controls (220.2 ± 147.6 pg/mL vs. 498.3 ± 224.4 pg/mL, p < 0.001). Skeletal muscle MOTS-c expression was also reduced in the PCOS group (74.2 ± 15.2 vs. 100.0 ± 8.5 arbitrary units; p = 0.005). Serum MOTS-c levels were inversely associated with total testosterone ( r = − 0.224, p = 0.046) and total cholesterol ( r = − 0.228, p = 0.044). Women with PCOS display reduced MOTS-c expression in both the circulation and skeletal muscle, suggesting reduced availability of this mitochondrial-derived peptide. Associations with hyperandrogenism and lipid profiles suggest a potential link between altered mitochondrial peptide biology and the endocrine–metabolic phenotype of PCOS. These findings suggest that MOTS-c may represent a potential marker of tissue-specific mitochondrial involvement in PCOS and warrant further investigation. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1038/s41598-026-39687-x.

Glucocorticoids, such as dexamethasone (DEXA), are effective therapeutics but cause severe muscle wasting. Mitochondrial-derived peptides (MDPs) are promising countermeasures, but their effectiveness is largely unexplored. We tested the hypothesis that the MDP S14G-humanin (HNG) and the mitochondrial open reading frame of the 12S rRNA-c (MOTS-c) mitigate DEXA-induced atrophy in human skeletal myotubes. Fully differentiated primary human myotubes were exposed to 10 μM DEXA ±10 μM HNG or 10 μM MOTS-c. DEXA decreased myotube size (area, p < 0.001) and differentiation (Fusion Index, p = 0.05). Additionally, DEXA increased both muscle ring finger protein 1 (MURF1, p < 0.001) and muscle atrophy F-box (MAFbx, p = 0.01) as well as peroxisome proliferator-activated receptor-gamma coactivator-1 alpha (PGC1α, p < 0.001). MOTS-c co-treatment with DEXA completely preserved myotube area (p < 0.001) and fusion index (p = 0.02), increased Akt phosphorylation (p = 0.0015) and blunted both MURF1 upregulation (p = 0.03) and STAT3 activation (p = 0.005) compared to DEXA alone. HNG co-treatment with DEXA preserved myotube area (p < 0.001), blunted DEXA-induced STAT3 activation (p = 0.027), but had no effect on fusion index or E3 ligase mRNA levels. Those findings suggest that MOTS-c could be an effective inhibitor of glucocorticoid-induced atrophy in human muscle, not only through selective inhibition of MURF1 but also by enhancing Akt signaling and suppressing STAT3 activation.

INTRODUCTION: MOTS-c (mitochondrial open reading frame of the 12S rRNA type-c) is a mitochondrial-derived peptide and regulator of metabolic homeostasis. Although its role in glucose and lipid metabolism is emerging, changes in circulating MOTS-c with obesity remain unclear. We hypothesized that circulating MOTS-c concentrations would be altered in obese vs. lean adults in associations with altered metabolic and inflammatory markers. METHODS: Circulating MOTS-c levels, metabolic parameters, and inflammatory markers were compared between 22 lean controls and 32 obese participants scheduled for bariatric surgery. Longitudinal changes in weight, MOTS-c levels, and metabolic markers were also analyzed in 10 of the obese patients before and 6 months after bariatric surgery. Additionally, adipose tissue MOTS-c expression was assessed by immunofluorescence in lean kidney donors (n = 6) and obese (n = 14) subjects. RESULTS: Circulating MOTS-c levels were significantly higher in obese compared to lean individuals (273 ± 56 vs. 223 ± 50 pg/mL; P < 0.01). BMI and HOMA-IR independently predicted elevated MOTS-c levels ( P = 0.035 and P = 0.032, respectively). MOTS-c showed a biphasic relationship with HOMA-IR, rising sharply above HOMA-IR of ∼ 6.6 mmol/L×µU/mL. Adipose tissue MOTS-c did not differ between the groups or correlate with circulating MOTS-c. Despite significant BMI improvements post-surgery ( P < 0.001), circulating MOTS-c levels remained unchanged ( P = 0.913). CONCLUSION: Circulating MOTS-c levels are elevated in obesity, exhibiting a nonlinear relationship with BMI and insulin resistance. MOTS-c may represent a compensatory metabolic response in obesity and insulin-resistant states, highlighting its potential as a clinical biomarker. This preliminary exploratory study warrants validation in larger and independent cohorts.

Mitochondria-derived peptides (MDPs) are bioactive molecules encoded by small open reading frames within mitochondrial DNA (mtDNA). Humanin, the first MDP to be discovered, functions as a cytoprotective factor, protecting cells from stress-induced apoptosis. Subsequent discoveries expanded this family to include Mitochondrial Open-reading-frame of the Twelve S rRNA-c (MOTS-c), a key regulator of metabolic homeostasis and stress adaptation, and the Small Humanin-Like Peptides (SHLP1-6), which modulate mitochondrial bioenergetics and insulin sensitivity. MDPs play critical roles in liver homeostasis by maintaining mitochondrial function and metabolic balance. Intracellularly, they modulate mitochondrial activity, oxidative stress, and apoptosis, promoting hepatocyte survival. Extracellularly, they act in autocrine, paracrine, or endocrine manners, engaging receptors or signaling pathways to regulate nuclear gene expression and metabolic adaptation. Emerging evidence highlights their relevance in metabolic dysfunction-associated steatotic liver disease (MASLD). Humanin exerts hepatoprotective effects by inhibiting apoptosis and modulating lipid metabolism. MOTS-c activates AMPK, regulates nuclear gene expression, suppresses fibrotic and inflammatory signaling, and restores mitochondrial function in MASLD and fibrosis models. SHLPs, particularly SHLP2, enhance mitochondrial function and insulin sensitivity, supporting glucose homeostasis and mitigating oxidative stress. Collectively, MDPs establish a novel paradigm in mitochondrial signaling, extending mtDNA function beyond energy production. This review summarizes current insights into MDP biology and highlights its emerging therapeutic potential in chronic liver disease.

Sarcopenia, a progressive skeletal muscle disorder marked by loss of mass and function, presents growing societal challenges due to limited therapeutic options. Here, we identify mitochondrial dysfunction and oxidative stress as central drivers of sarcopenia through integrated bioinformatics and clinical validation. To address this pathophysiology, we engineer a muscle-targeted nanocomposite (BP-PEG-MOTS-c, BM) combining mitochondrial-derived peptide MOTS-c with antioxidant black phosphorus nanosheets (BP). BM exhibits dual functionality: MOTS-c restores mitochondrial function, while BP synergistically amplifies ROS scavenging capacity. In cellular and murine models with age-related sarcopenia, BM treatment alleviates muscle dysfunction and muscle loss, concurrently normalizing mitochondrial function and reducing lipid peroxidation. Mechanistic profiling via RNA-seq reveals BM's activation of PI3K/AKT/Nrf2 and suppression of ROS/p38 MAPK signaling pathway, mediating antioxidant responses and maintenance of mitochondrial homeostasis. The nanocomposite demonstrats superior biocompatibility in toxicity assays, outperforming conventional delivery systems. Our findings establish that BM has been established as a promising mitochondrial redox modulator with translational potential for sarcopenia and related age-associated pathologies.