MOTS-c

MOTS-c: A promising mitochondrial-derived peptide for therapeutic exploitation.

Mitochondrial ORF of the 12S rRNA Type-C (MOTS-c) is a mitochondrial-derived peptide composed of 16 amino acids encoded by the 12S rRNA region of the mitochondrial genome. The MOTS-c protein is transferred to the nucleus during metabolic stress and directs the expression of nuclear genes to promote cell balance. Different tissues co-expressed the protein with mitochondria, and plasma also contained the protein, but its level decreased with age. In addition, MOTS-c has been shown to improve glucose metabolism in skeletal muscle, which indicates its benefits for diseases such as diabetes, obesity, and aging. Nevertheless, MOTS-c has been used less frequently in disease treatment, and no effective method of applying MOTS-c in the clinic has been developed. Throughout this paper, we discussed the discovery and physiological function of mitochondrial-derived polypeptide MOTS-c, and the application of MOTS-c in the treatment of various diseases, such as aging, cardiovascular disease, insulin resistance, and inflammation. To provide additional ideas for future research and development, we tapped into the molecular mechanisms and therapeutic potentials of MOTS-c to improve diseases and combined the technology with synthetic biology in order to offer a new approach to its development and application.

The mitochondrial-derived peptide MOTS-c promotes metabolic homeostasis and reduces obesity and insulin resistance.

Mitochondria are known to be functional organelles, but their role as a signaling unit is increasingly being appreciated. The identification of a short open reading frame (sORF) in the mitochondrial DNA (mtDNA) that encodes a signaling peptide, humanin, suggests the possible existence of additional sORFs in the mtDNA. Here we report a sORF within the mitochondrial 12S rRNA encoding a 16-amino-acid peptide named MOTS-c (mitochondrial open reading frame of the 12S rRNA-c) that regulates insulin sensitivity and metabolic homeostasis. Its primary target organ appears to be the skeletal muscle, and its cellular actions inhibit the folate cycle and its tethered de novo purine biosynthesis, leading to AMPK activation. MOTS-c treatment in mice prevented age-dependent and high-fat-diet-induced insulin resistance, as well as diet-induced obesity. These results suggest that mitochondria may actively regulate metabolic homeostasis at the cellular and organismal level via peptides encoded within their genome.

Mitochondrial-Derived Peptide MOTS-c Suppresses Ovarian Cancer Progression by Attenuating USP7-Mediated LARS1 Deubiquitination.

Mitochondrial-nuclear communication plays a vital role in maintaining cellular homeostasis. MOTS-c, a short peptide derived from the 12S rRNA of mitochondrial DNA, has been suggested as a retrograde mitochondrial signal. Although recent clinical studies have suggested a possible link between MOTS-c and human cancer, the role of MOTS-c in tumorigenesis has yet to be investigated. Here, MOTS-c levels are found to be reduced in both serum and tumor tissues from ovarian cancer (OC) patients, which are associated with poor patients' prognosis. Exogenous MOTS-c inhibits the proliferation, migration and invasion of OC cells, and induces cell cycle arrest and apoptosis. Mechanistically, MOTS-c interacts with LARS1 and promotes its ubiquitination and proteasomal degradation. In addition, USP7 was identified as a deubiquitinase of LARS1, and MOTS-c can attenuates USP7-mediated LARS1 deubiquitination by competing with USP7 for binding to LARS1. Besides, LARS1 was found to be increased and play an important oncogenic function in OC. More importantly, MOTS-c displays a marked anti-tumor effect on OC growth without systemic toxicity in vivo. In conclusion, this study reveals a crucial role of MOTS-c in OC and provides a possibility for MOTS-c as a therapeutic target for the treatment of this manlignacy.

The mitochondrial-derived peptide MOTS-c relieves hyperglycemia and insulin resistance in gestational diabetes mellitus.

The most common complication during pregnancy, gestational diabetes mellitus (GDM), can cause adverse pregnancy outcomes and result in the mother and infant having a higher risk of developing type 2 diabetes after pregnancy. However, existing therapies for GDM remain scant, with the most common being lifestyle intervention and appropriate insulin treatment. MOTS-c, a mitochondrial-derived peptide, can target skeletal muscle and enhance glucose metabolism. Here, we demonstrate that MOTS-c can be an effective treatment for GDM. A GDM mouse model was established by short term high-fat diet combined with low-dose streptozotocin (STZ) treatment while MOTS-c was administrated daily during pregnancy. GDM symptoms such as blood glucose and insulin levels, glucose and insulin tolerance, as well as reproductive outcomes were investigated. MOTS-c significantly alleviated hyperglycemia, improved insulin sensitivity and glucose tolerance, and reduced birth weight and the death of offspring induced by GDM. Similar to a previous study, MOTS-c also could activate insulin sensitivity in the skeletal muscle of GDM mice and elevate glucose uptake in vitro. In addition, we found that MOTS-c protects pancreatic β-cell from STZ-mediated injury. Taken together, our findings demonstrate that MOTS-c could be a promising strategy for the treatment of GDM.

The Mitochondrial-Encoded Peptide MOTS-c Translocates to the Nucleus to Regulate Nuclear Gene Expression in Response to Metabolic Stress.

Cellular homeostasis is coordinated through communication between mitochondria and the nucleus, organelles that each possess their own genomes. Whereas the mitochondrial genome is regulated by factors encoded in the nucleus, the nuclear genome is currently not known to be actively controlled by factors encoded in the mitochondrial DNA. Here, we show that MOTS-c, a peptide encoded in the mitochondrial genome, translocates to the nucleus and regulates nuclear gene expression following metabolic stress in a 5'-adenosine monophosphate-activated protein kinase (AMPK)-dependent manner. In the nucleus, MOTS-c regulated a broad range of genes in response to glucose restriction, including those with antioxidant response elements (ARE), and interacted with ARE-regulating stress-responsive transcription factors, such as nuclear factor erythroid 2-related factor 2 (NFE2L2/NRF2). Our findings indicate that the mitochondrial and nuclear genomes co-evolved to independently encode for factors to cross-regulate each other, suggesting that mitonuclear communication is genetically integrated.

Mitochondrial-derived microprotein MOTS-c attenuates immobilization-induced skeletal muscle atrophy by suppressing lipid infiltration.

Mitochondrial open reading frame of the 12S ribosomal RNA type-c (MOTS-c), a mitochondrial microprotein, has been described as a novel regulator of glucose and lipid metabolism. In addition to its role as a metabolic regulator, MOTS-c prevents skeletal muscle atrophy in high fat-fed mice. Here, we examined the preventive effect of MOTS-c on skeletal muscle mass, using an immobilization-induced muscle atrophy model, and explored its underlying mechanisms. Male C57BL/6J mice (10 wk old) were randomly assigned to one of the three experimental groups: nonimmobilization control group (sterilized water injection), immobilization control group (sterilized water injection), and immobilization and MOTS-c-treated group (15 mg/kg/day MOTS-c injection). We used casting tape for the immobilization experiment. After 8 days of the experimental period, skeletal muscle samples were collected and used for Western blotting, RNA sequencing, and lipid and collagen assays. Immobilization reduced ∼15% of muscle mass, whereas MOTS-c treatment attenuated muscle loss, with only a 5% reduction. MOTS-c treatment also normalized phospho-AKT, phospho-FOXO1, and phospho-FOXO3a expression levels and reduced circulating inflammatory cytokines, such as interleukin-1b (IL-1β), interleukin-6 (IL-6), chemokine C-X-C motif ligand 1 (CXCL1), and monocyte chemoattractant protein 1 (MCP-1), in immobilized mice. Unbiased RNA sequencing and its downstream analyses demonstrated that MOTS-c modified adipogenesis-modulating gene expression within the peroxisome proliferator-activated receptor (PPAR) pathway. Supporting this observation, muscle fatty acid levels were lower in the MOTS-c-treated group than in the casted control mice. These results suggest that MOTS-c treatment inhibits skeletal muscle lipid infiltration by regulating adipogenesis-related genes and prevents immobilization-induced muscle atrophy.NEW & NOTEWORTHY MOTS-c, a mitochondrial microprotein, attenuates immobilization-induced skeletal muscle atrophy. MOTS-c treatment improves systemic inflammation and skeletal muscle AKT/FOXOs signaling pathways. Furthermore, unbiased RNA sequencing and subsequent assays revealed that MOTS-c prevents lipid infiltration in skeletal muscle. Since lipid accumulation is one of the common pathologies among other skeletal muscle atrophies induced by aging, obesity, cancer cachexia, and denervation, MOTS-c treatment could be effective in other muscle atrophy models as well.

The mitochondrial-derived peptide MOTS-c suppresses ferroptosis and alleviates acute lung injury induced by myocardial ischemia reperfusion via PPARγ signaling pathway.

Acute lung injury (ALI) is a life-threatening complication of cardiac surgery that has a high rate of morbidity and mortality. Epithelial ferroptosis is believed to be involved in the pathogenesis of ALI. MOTS-c has been reported to play a role in regulating inflammation and sepsis-associated ALI. The purpose of this study is to observe the effect of MOTS-c on myocardial ischemia reperfusion (MIR)-induced ALI and ferroptosis. In humans, we used ELISA kits to investigate MOTS-c and malondialdehyde (MDA) levels in patients undergoing off-pump coronary artery bypass grafting (CABG). In vivo, we pretreated Sprague-Dawley rats with MOTS-c, Ferrostatin-1 and Fe-citrate(Ⅲ). We conducted Hematoxylin and Eosin (H&E) staining and detection of ferroptosis-related genes in MIR-induced ALI rats. In vitro, we evaluated the effect of MOTS-c on hypoxia regeneration (HR)-induced mouse lung epithelial-12 (MLE-12) ferroptosis and analyzed the expression of PPARγ through western blotting. We found that circulating MOTS-c levels were decreased in postoperative ALI patients after off-pump CABG, and that ferroptosis contributed to ALI induced by MIR in rats. MOTS-c suppressed ferroptosis and alleviated ALI induced by MIR, and the protective effect of MOTS-c- was dependent on PPARγ signaling pathway. Additionally, HR promoted ferroptosis in MLE-12 cells, and MOTS-c inhibited ferroptosis against HR through the PPARγ signaling pathway. These findings highlight the therapeutic potential of MOTS-c for improving postoperative ALI induced by cardiac surgery.

Mitochondrial-Encoded Peptide MOTS-c, Diabetes, and Aging-Related Diseases.

Mitochondria are complex metabolic organelles with manifold pathophysiological implications in diabetes. Currently published mitochondrial-encoded peptides, which are expressed from the mitochondrial open reading frame of the 12S ribosomal RNA type-c (MOTS-c), 16S rRNA (humanin and short humanin like peptide 1-6 [SHLP1-6]), or small human mitochondrial open reading frame over serine tRNA (SHMOOSE) are associated with regulation of cellular metabolism and insulin action in age-related diseases, such as type 2 diabetes mellitus. This review focuses mainly on recent advances in MOTS-c research with regards to diabetes, including both type 1 and type 2. The emerging understanding of MOTS-c in diabetes may provide insight into the development of new therapies for diabetes and other age or senescence-related diseases.

MOTS-c, the Most Recent Mitochondrial Derived Peptide in Human Aging and Age-Related Diseases.

MOTS-c, a 16 amino acid mitochondrial derived peptide, is encoded from the 12S rRNA region of the mitochondrial genome. Under stress conditions, MOTS-c translocates to the nucleus where it regulates a wide range of genes in response to metabolic dysfunction. It is colocalized to mitochondria in various tissues and is found in plasma, but the levels decline with age. Since MOTS-c has important cellular functions as well as a possible hormonal role, it has been shown to have beneficial effects on age-related diseases including Diabetes, Cardiovascular diseases, Osteoporosis, postmenopausal obesity and Alzheimer. Aging is characterized by gradual loss of (mitochondrial) metabolic balance, decreased muscle homeostasis and eventual diminished physical capability, which potentially can be reversed with MOTS-c treatment. This review examines the latest findings on biological effects of MOTS-c as a nuclear regulatory peptide and focuses on the role of MOTS-c in aging and age-related disorders, including mechanisms of action and therapeutic potential.

MOTS-c: A novel mitochondrial-derived peptide regulating muscle and fat metabolism.

Mitochondria are ancient organelles that are thought to have emerged from once free-living α-proto-bacteria. As such, they still possess several bacterial-like qualities, including a semi-autonomous genetic system, complete with an independent genome and a unique genetic code. The bacterial-like circular mitochondrial DNA (mtDNA) has been described to encode 37 genes, including 22 tRNAs, 2 rRNAs, and 13 mRNAs. Two additional peptides reported to originate from the mtDNA, namely humanin (Hashimoto et al., 2001; Ikone et al., 2003; Guo et al., 2003) [1-3] and MOTS-c (mitochondrial ORF of the twelve S c) (Lee et al., 2015) [4], indicate a larger mitochondrial genetic repertoire (Shokolenko and Alexeyev, 2015) [5]. These mitochondrial-derived peptides (MDPs) have profound and distinct biological activities and provide a paradigm-shifting concept of active mitochondrial-encoded signals that act at the cellular and organismal level (i.e. mitochondrial hormone) (da Cunha et al., 2015; Quiros et al., 2016) [6,7]. Considering that mitochondria are the single most important metabolic organelle, it is not surprising that these MDPs have metabolic actions. MOTS-c has been shown to target the skeletal muscle and enhance glucose metabolism. As such, MOTS-c has implications in the regulation of obesity, diabetes, exercise, and longevity, representing an entirely novel mitochondrial signaling mechanism to regulate metabolism within and between cells.

Mitochondria-derived peptide MOTS-c restores mitochondrial respiration in type 2 diabetic heart.

Type 2 diabetes (T2D) is a global epidemic, and heart failure is the primary cause of premature death among T2D patients. Mitochondrial dysfunction has been linked to decreased contractile performance in diabetic heart, partly due to a disturbance in the mitochondrial capacity to supply adequate metabolic energy to contractile proteins. MOTS-c, a newly discovered mitochondrial-derived peptide, has shown promise as a therapeutic for restoring energy homeostasis and muscle function in metabolic diseases. However, whether MOTS-c therapy improves T2D heart function by increasing mitochondrial bioenergetic function remains unknown. Here we studied the mitochondrial bioenergetic function of heart tissues isolated from a rat model mimicking type 2 diabetes induced by a high-fat diet and low-dose streptozotocin. Treated diabetic group received MOTS-c (15 mg/kg) daily injection for 3 weeks. We employed high-resolution respirometric and fluorometric techniques to simultaneously assess mitochondrial ATP production and hydrolysis capacity, reactive oxygen species (ROS) production, and oxygen flux in cardiac tissue homogenates. We found that untreated T2D rats had hyperglycemia, poor glucose control, and left ventricular hypertrophy relative to controls. T2D mitochondria showed decreased oxygen flux at the oxidative phosphorylation (OXP) while ROS production, ATP production and hydrolysis rates remained unchanged. Diabetic rats treated with MOTS-c showed decreased fasting glucose levels, improved glucose homeostasis, and decreased degree of cardiac hypertrophy. At the subcellular level, MOTS-c treated mitochondria showed increased OXPHOS respiration and ROS levels and decreased ATP hydrolysis rate during anoxic conditions. These findings demonstrate beneficial effects of MOTS-c treatment on glucose homeostasis and suggest a useful therapeutic option for diabetic-related cardiomyopathy and mitochondrial dysfunction.

Mitochondrial-encoded peptide MOTS-c prevents pancreatic islet cell senescence to delay diabetes.

Mitochondria are crucial for cell survival and function, partly through peptides encoded by the mitochondrial genome. Although mitochondrial dysfunction is a hallmark of age-related diseases and senescence, the role of mitochondrial-genome-encoded peptides in pancreatic β-cell senescence during type 1 and type 2 diabetes pathogenesis is largely unexplored. Here we show that MOTS-c levels decrease with aging and senescence in pancreatic islet cells. Treating aged C57BL/6 mouse pancreatic islets with MOTS-c reduced pancreatic islet senescence by modulating nuclear gene expression and metabolites involved in β-cell senescence. MOTS-c treatment improved pancreatic islet senescence and glucose intolerance in S961-treated C57BL/6 and in nonobese diabetic mice. In humans, circulating MOTS-c levels are lower in type 2 diabetes patients compared with healthy controls. Our findings suggest that mitochondrial-encoded MOTS-c regulate pancreatic islet cell senescence and that MOTS-c could act as a senotherapeutic agent to prevent pancreatic islet cell senescence and diabetes progression.

Mitochondrial-Derived Peptide MOTS-c Increases Adipose Thermogenic Activation to Promote Cold Adaptation.

Cold exposure stress causes hypothermia, cognitive impairment, liver injury, and cardiovascular diseases, thereby increasing morbidity and mortality. Paradoxically, cold acclimation is believed to confer metabolic improvement to allow individuals to adapt to cold, harsh conditions and to protect them from cold stress-induced diseases. However, the therapeutic strategy to enhance cold acclimation remains less studied. Here, we demonstrate that the mitochondrial-derived peptide MOTS-c efficiently promotes cold adaptation. Following cold exposure, the improvement of adipose non-shivering thermogenesis facilitated cold adaptation. MOTS-c, a newly identified peptide, is secreted by mitochondria. In this study, we observed that the level of MOTS-c in serum decreased after cold stress. MOTS-c treatment enhanced cold tolerance and reduced lipid trafficking to the liver. In addition, MOTS-c dramatically upregulated brown adipose tissue (BAT) thermogenic gene expression and increased white fat "browning". This effect might have been mediated by MOTS-c-activated phosphorylation of the ERK signaling pathway. The inhibition of ERK signaling disturbed the up-regulatory effect of MOTS-c on thermogenesis. In summary, our results indicate that MOTS-c treatment is a potential therapeutic strategy for defending against cold stress by increasing the adipose thermogenesis via the ERK pathway.

The Mitochondrial-Derived Peptide MOTS-c Alleviates Radiation Pneumonitis via an Nrf2-Dependent Mechanism.

Radiation pneumonitis (RP) is a prevalent and fatal complication of thoracic radiotherapy due to the lack of effective treatment options. RP primarily arises from mitochondrial injury in lung epithelial cells. The mitochondrial-derived peptide MOTS-c has demonstrated protective effects against various diseases by mitigating mitochondrial injury. C57BL/6 mice were exposed to 20 Gy of lung irradiation (IR) and received daily intraperitoneal injections of MOTS-c for 2 weeks. MOTS-c significantly ameliorated lung tissue damage, inflammation, and oxidative stress caused by radiation. Meanwhile, MOTS-c reversed the apoptosis and mitochondrial damage of alveolar epithelial cells in RP mice. Furthermore, MOTS-c significantly inhibited oxidative stress and mitochondrial damage in MLE-12 cells and primary mouse lung epithelial cells. Mechanistically, MOTS-c increased the nuclear factor erythroid 2-related factor (Nrf2) level and promoted its nuclear translocation. Notably, Nrf2 deficiency abolished the protective function of MOTS-c in mice with RP. In conclusion, MOTS-c alleviates RP by protecting mitochondrial function through an Nrf2-dependent mechanism, indicating that MOTS-c may be a novel potential protective agent against RP.

Exercise-Induced Muscle-Fat Crosstalk: Molecular Mediators and Their Pharmacological Modulation for the Maintenance of Metabolic Flexibility in Aging.

Regular physical activity induces a dynamic crosstalk between skeletal muscle and adipose tissue, modulating the key molecular pathways that underlie metabolic flexibility, mitochondrial function, and inflammation. This review highlights the role of myokines and adipokines-particularly IL-6, irisin, leptin, and adiponectin-in orchestrating muscle-adipose tissue communication during exercise. Exercise stimulates AMPK, PGC-1α, and SIRT1 signaling, promoting mitochondrial biogenesis, fatty acid oxidation, and autophagy, while also regulating muscle hypertrophy through the PI3K/Akt/mTOR and Wnt/β-catenin pathways. Simultaneously, adipose-derived factors like leptin and adiponectin modulate skeletal muscle metabolism via JAK/STAT3 and AdipoR1-mediated AMPK activation. Additionally, emerging exercise mimetics such as the mitochondrial-derived peptide MOTS-c and myostatin inhibitors are highlighted for their roles in increasing muscle mass, the browning of white adipose tissue, and improving systemic metabolic function. The review also addresses the role of anti-inflammatory compounds, including omega-3 polyunsaturated fatty acids and low-dose aspirin, in mitigating NF-κB and IL-6 signaling to protect mitochondrial health. The resulting metabolic flexibility, defined as the ability to efficiently switch between lipid and glucose oxidation, is enhanced through repeated exercise, counteracting age- and disease-related mitochondrial and functional decline. Together, these adaptations demonstrate the importance of inter-tissue signaling in maintaining energy homeostasis and preventing sarcopenia, obesity, and insulin resistance. Finally, here we propose a stratified treatment algorithm based on common age-related comorbidities, offering a framework for precision-based interventions that may offer a promising strategy to preserve metabolic plasticity and delay the age-associated decline in cardiometabolic health.

MOTS-c, a mitochondrial-derived peptide, ameliorates lysosomal membrane permeability and improves survival of soft tissue transplantation.

Distal ischemic necrosis remains a major challenge in reconstructive surgery. Mitochondria and lysosomes interact via signaling and membrane contacts to maintain cellular homeostasis. Mitochondrial-derived peptide MOTS-c, encoded by the MT-RNR1/12S rRNA open reading frame, enhances mitochondrial function by reducing reactive oxygen species (ROS) and stabilizing the membrane potential, potentially preserving lysosomal integrity and reducing lysosomal membrane permeabilization (LMP). This study investigated the protective effects and underlying mechanisms of MOTS-c in ischemic flaps. RNA sequencing explored MOTS-c mechanisms in ischemic flaps. Tissue clearing, laser speckle contrast imaging and Doppler analyses revealed improved blood flow perfusion following MOTS-c treatment. Histological staining (HE, Masson, F-CHP) demonstrated enhanced angiogenesis and collagen remodeling. Western blotting, ELISA, and immunofluorescence were used to assess pyroptosis, macroautophagy/autophagy, LMP, and MAPK1/ERK2-MAPK3/ERK1-NFKB/NF-κB pathway-related proteins. MOTS-c reduced endothelial pyroptosis, enhanced autophagy, and attenuated LMP in ischemic flaps. Mechanistically, in vivo overexpression of PLA2G4A/cPLA2 (phospholipase A2, group IVA (calcium, calcium dependent)) via AAV confirmed that MOTS-c enhances autophagy and reduces pyroptosis and LMP by suppressing PLA2G4A phosphorylation. Furthermore, MOTS-c inhibited PLA2G4A via the MAPK1-MAPK3-NFKB signaling cascade, thereby reducing LMP and enhancing flap survival. These findings suggest that MOTS-c restores cellular homeostasis by targeting the PLA2G4A-LMP axis, representing a promising therapeutic strategy for improving outcomes in ischemic flap surgery.Abbreviations: AA = arachidonic acid, AAV = adeno-associated virus, ACTA2/α-SMA = actin alpha 2, smooth muscle, aorta, ALs = autolysosomes, BECN1 = beclin 1, CASP1 = caspase 1, CQ = chloroquine, CTSB = cathepsin B, CTSD = cathepsin D, CTSL = cathepsin L, Co-IP = co-immunoprecipitation, DEGs = differentially expressed genes, ELISA = enzyme-linked immunosorbent assay, F-CHP = 5-FAM-conjugated collagen hybridizing peptide staining, GSDMD = gasdermin D, GO = gene Ontology, GPT/ALT = glutamic pyruvic transaminase, soluble, GOT1/AST = glutamic-oxaloacetic transaminase 1, soluble, HE = hematoxylin-eosin, HUVECs = human umbilical vein endothelial cells, IP/MS = immunoprecipitation coupled with mass spectrometry, IL1B/IL-1β = interleukin 1 beta, IL18 = interleukin 18, IP = intraperitoneal injection, IV = intravenous injection, LDBF = laser Doppler blood flow, LMP = lysosomal membrane permeability, MAP1LC3/LC3 = microtubule-associated protein 1 light chain 3, MAPK = mitogen-activated protein kinase, NAGLU = alpha-N-acetylglucosaminidase (Sanfilippo disease IIIB), NFKB/NF-κB = nuclear factor kappa B, NLRP1 = NLR family pyrin domain containing 1, NLRP3 = NLR family pyrin domain containing 3, PECAM1/CD31 = platelet/endothelial cell adhesion molecule 1, PLA2G4A/cPLA2 = phospholipase A2, group IVA (cytosolic, calcium-dependent), PYCARD/ASC = PYD and CARD domain containing, PIK3C3/VPS34 = phosphatidylinositol 3-kinase catalytic subunit type 3, PMA = phorbol 12-myristate 13-acetate, ROS = reactive oxygen speciesSQSTM1/p62 = sequestosome 1, SPR = surface plasmon resonance, scRNA-seq = single-cell RNA sequencing, UMAP = uniform manifold approximation and projection, WB = western blotting.

MOTS-c Functionally Prevents Metabolic Disorders.

Mitochondrial-derived peptides are a family of peptides encoded by short open reading frames in the mitochondrial genome, which have regulatory effects on mitochondrial functions, gene expression, and metabolic homeostasis of the body. As a new member of the mitochondrial-derived peptide family, mitochondrial open reading frame of the 12S rRNA-c (MOTS-c) is regarding a peptide hormone that could reduce insulin resistance, prevent obesity, improve muscle function, promote bone metabolism, enhance immune regulation, and postpone aging. MOTS-c plays these physiological functions mainly through activating the AICAR-AMPK signaling pathways by disrupting the folate-methionine cycle in cells. Recent studies have shown that the above hormonal effect can be achieved through MOTS-c regulating the expression of genes such as GLUT4, STAT3, and IL-10. However, there is a lack of articles summarizing the genes and pathways involved in the physiological activity of MOTS-c. This article aims to summarize and interpret the interesting and updated findings of MOTS-c-associated genes and pathways involved in pathological metabolic processes. Finally, it is expected to develop novel diagnostic markers and treatment approaches with MOTS-c to prevent and treat metabolic disorders in the future.

Mitochondria-derived peptide MOTS-c: effects and mechanisms related to stress, metabolism and aging.

MOTS-c is a peptide encoded by the short open reading frame of the mitochondrial 12S rRNA gene. It is significantly expressed in response to stress or exercise and translocated to the nucleus, where it regulates the expression of stress adaptation-related genes with antioxidant response elements (ARE). MOTS-c mainly acts through the Folate-AICAR-AMPK pathway, thereby influencing energy metabolism, insulin resistance, inflammatory response, exercise, aging and aging-related pathologies. Because of the potential role of MOTS-c in maintaining energy and stress homeostasis to promote healthy aging, especially in view of the increasing aging of the global population, it is highly pertinent to summarize the relevant studies. This review summarizes the retrograde signaling of MOTS-c toward the nucleus, the regulation of energy metabolism, stress homeostasis, and aging-related pathological processes, as well as the underlying molecular mechanisms.

Mitochondrial-derived peptides and exercise.

Acute exercise, and in particular aerobic exercise, increases skeletal muscle energy demand causing mitochondrial stress, and mitochondrial-related adaptations which are a hallmark of exercise training. Given that mitochondria are central players in the exercise response, it is imperative that they have networks that can communicate their status both intra- and inter-cellularly. Peptides encoded by short open-reading frames within mitochondrial DNA, mitochondrial-derived peptides (MDPs), have been suggested to form a newly recognised branch of this retrograde signalling cascade that contribute to coordinating the adaptive response to regular exercise. Here we summarise the recent evidence that acute high intensity exercise in humans can increase concentrations of the MDPs humanin and MOTS-c in skeletal muscle and plasma, and speculate on the mechanisms controlling MDP responses to exercise stress. Evidence that exercise training results in chronic changes in MDP expression within tissues and the circulation is conflicting and may depend on the mode, duration, intensity of training plan and participant characteristics. Further research is required to define the effect of these variables on MDPs and to determine whether MDPs other than MOTS-c have exercise mimetic properties. MOTS-c treatment of young and aged mice improves exercise capacity/performance and leads to adaptions that are similar to that of being physically active (weight loss, increased antioxidant capacity and improved insulin sensitivity), however, studies utilising a MOTS-c inactivating genetic variant or combination of exercise + MOTS-c treatment in mice suggest that there are distinct and overlapping pathways through which exercise and MOTS-c evoke metabolic benefits. Overall, MOTS-c, and potentially other MDPs, may be exercise-sensitive myokines and further work is required to define inter- and intra-tissue targets in an exercise context.

Mitochondrial-Derived Peptides Exacerbate Senescence.

Mitochondrial-derived peptides (MDPs), encoded by mitochondrial DNA, play a cytoprotective role by helping preserve mitochondrial function and cell viability under stressful conditions. Humanin and its homologs and MOTS-c are two of several MDPs hypothesized to have antiaging activity based on correlative studies. For example, humanin plasma levels are inversely correlated with growth hormone and insulin-like growth factor 1 expression, which may promote accelerated aging. Humanin has been shown to protect cells from beta amyloid toxicity and preserve endothelial cell function in a mouse model of atherosclerosis. Furthermore, both humanin and MOTS-c improve insulin sensitivity in mouse models of type 2 diabetes. Recently it was reported that a potent analogue of humanin blocks cardiac fibrosis in aging mice. Although it has been hypothesized that MDPs might have senolytic activity, in a recent report humanin and MOTS-c both exacerbate the senescence-associated-secretory-phenotype (SASP) in senescent cells by stimulating the secretion of IL-6, IL-1β, IL-8, IL-10 and tumor necrosis factor α. It appears that the cytoprotective activity of the MDPs may be permissive for increased expression of a set of proinflammatory cytokines. Given the potential benefits of MDPs in many of the same diseases associated with the presence of senescent cells, a combination of senolytic and MDP-based treatments may be additive or synergistic. The MDPs would protect normal cells, whereas senescent cells would be eliminated by the senolytic therapy. It is even possible that MDPs by increasing the SASP phenotype would make the senescent cells more apt to be cleared by the immune system or more sensitive to senolytics. In contrast, if the MDPs actually cytoprotect the senescent cells, then the treatment can be performed serially with the senolytic used first.

Mitochondrial-derived peptide MOTS-c targets SLC7A11 to preserve spermatogenesis by suppressing ferroptosis.

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.

MOTS-c attenuates lung ischemia-reperfusion injury via MYH9-Dependent nuclear translocation and transcriptional activation of antioxidant genes.

Acute respiratory distress syndrome (ARDS) following cardiopulmonary bypass (CPB) is driven by oxidative stress during lung ischemia-reperfusion injury (LIRI). Mitochondrial-derived peptide MOTS-c has emerged as a regulator of mitochondrial-nuclear communication, yet its role in CPB-induced ARDS remains unclear. Here, we identify MOTS-c as a critical mediator of endothelial protection against LIRI through MYH9-dependent nuclear translocation and transcriptional activation of antioxidant genes. In rat LIRI models, endothelial cells exhibited the most significant MOTS-c upregulation, correlating with barrier preservation and reduced oxidative stress. Mechanistically, hypoxia-reoxygenation (HR) triggered reactive oxygen species (ROS)-dependent phosphorylation of MYH9 at Ser1943 via casein kinase II subunit alpha (CK2A), enabling MOTS-c binding to MYH9-γ-Actin complexes for nuclear transport. RNA sequencing (RNA-seq) combined with chromatin immunoprecipitation sequencing (ChIP-seq) revealed direct MOTS-c interaction with promoters of antioxidant genes (e.g., HMOX1, NQO1), which harbor antioxidant response elements (AREs). Clinically, serum MOTS-c increments within 24 h post-CPB (ΔMOTS-c) outperformed traditional biomarkers in predicting ARDS incidence, with multivariate models incorporating ΔMOTS-c achieving superior discriminative power (AUC = 0.885). Exogenous MOTS-c administration in rats attenuated lung injury by reducing oxidative damage, inflammation, and mortality, recapitulating endogenous protective mechanisms. Our findings establish MOTS-c as a dual-function molecule-acting via ROS-CK2A-MYH9 signaling to activate nuclear antioxidant defenses and serving as a prognostic biomarker for CPB-related complications. This study bridges mitochondrial dynamics, nuclear transcriptional regulation, and clinical outcomes, offering novel preventive avenues for IRI-associated pathologies.

MOTS-c modulates skeletal muscle function by directly binding and activating CK2.

MOTS-c is a mitochondrial microprotein that improves metabolism. Here, we demonstrate CK2 is a direct and functional target of MOTS-c. MOTS-c directly binds to CK2 and activates it in cell-free systems. MOTS-c administration to mice prevented skeletal muscle atrophy and enhanced muscle glucose uptake, which were blunted by suppressing CK2 activity. Interestingly, the effects of MOTS-c are tissue-specific. Systemically administered MOTS-c binds to CK2 in fat and muscle, yet stimulates CK2 activity in muscle while suppressing it in fat by differentially modifying CK2-interacting proteins. Notably, a naturally occurring MOTS-c variant, K14Q MOTS-c, has reduced binding to CK2 and does not activate it or elicit its effects. Male K14Q MOTS-c carriers exhibited a higher risk of sarcopenia and type 2 diabetes (T2D) in an age- and physical-activity-dependent manner, whereas females had an age-specific reduced risk of T2D. Altogether, these findings provide evidence that CK2 is required for MOTS-c effects.

Mitochondria-encoded peptide MOTS-c participates in plasma membrane repair by facilitating the translocation of TRIM72 to membrane.

Rationale: An impairment of plasma membrane repair has been implicated in various diseases such as muscular dystrophy and ischemia/reperfusion injury. MOTS-c, a short peptide encoded by mitochondria, has been shown to pass through the plasma membrane into the bloodstream. This study determined whether this biological behavior was involved in membrane repair and its underlying mechanism. Methods and Results: In human participants, the level of MOTS-c was positively correlated with the abundance of mitochondria, and the membrane repair molecule TRIM72. In contrast to high-intensity eccentric exercise, moderate-intensity exercise improved sarcolemma integrity and physical performance, accompanied by an increase of mitochondria beneath the damaged sarcolemma and secretion of MOTS-c. Furthermore, moderate-intensity exercise increased the interaction between MOTS-c and TRIM72, and MOTS-c facilitated the trafficking of TRIM72 to the sarcolemma. In vitro studies demonstrated that MOTS-c attenuated membrane damage induced by hypotonic solution, which could be blocked by siRNA-TRIM72, but not AMPK inhibitor. Co-immunoprecipitation study showed that MOTS-c interacted with TRIM72 C-terminus, but not N-terminus. The dynamic membrane repair assay revealed that MOTS-c boosted the trafficking of TRIM72 to the injured membrane. However, MOTS-c itself had negligible effects on membrane repair, which was recapitulated in TRIM72-/- mice. Unexpectedly, MOTS-c still increased the fusion of vesicles with the membrane in TRIM72-/- mice, and dot blot analysis revealed an interaction between MOTS-c and phosphatidylinositol (4,5) bisphosphate [PtdIns (4,5) P2]. Finally, MOTS-c blunted ischemia/reperfusion-induced membrane disruption, and preserved heart function. Conclusions: MOTS-c/TRIM72-mediated membrane integrity improvement participates in mitochondria-triggered membrane repair. An interaction between MOTS-c and plasma lipid contributes to the fusion of vesicles with membrane. Our data provide a novel therapeutic strategy for rescuing organ function by facilitating membrane repair with MOTS-c.

Mitochondrial-derived peptides in energy metabolism.

Mitochondrial-derived peptides (MDPs) are small bioactive peptides encoded by short open-reading frames (sORF) in mitochondrial DNA that do not necessarily have traditional hallmarks of protein-coding genes. To date, eight MDPs have been identified, all of which have been shown to have various cyto- or metaboloprotective properties. The 12S ribosomal RNA (MT-RNR1) gene harbors the sequence for MOTS-c, whereas the other seven MDPs [humanin and small humanin-like peptides (SHLP) 1-6] are encoded by the 16S ribosomal RNA gene. Here, we review the evidence that endogenous MDPs are sensitive to changes in metabolism, showing that metabolic conditions like obesity, diabetes, and aging are associated with lower circulating MDPs, whereas in humans muscle MDP expression is upregulated in response to stress that perturbs the mitochondria like exercise, some mtDNA mutation-associated diseases, and healthy aging, which potentially suggests a tissue-specific response aimed at restoring cellular or mitochondrial homeostasis. Consistent with this, treatment of rodents with humanin, MOTS-c, and SHLP2 can enhance insulin sensitivity and offer protection against a range of age-associated metabolic disorders. Furthermore, assessing how mtDNA variants alter the functions of MDPs is beginning to provide evidence that MDPs are metabolic signal transducers in humans. Taken together, MDPs appear to form an important aspect of a retrograde signaling network that communicates mitochondrial status with the wider cell and to distal tissues to modulate adaptative responses to metabolic stress. It remains to be fully determined whether the metaboloprotective properties of MDPs can be harnessed into therapies for metabolic disease.

Safety and Efficacy of Approved and Unapproved Peptide Therapies for Musculoskeletal Injuries and Athletic Performance.

Peptides are short chains of amino acids with a unique pharmacological niche between small-molecule drugs and large proteins. Their use in sports medicine is rapidly expanding, driven by patient demand for accelerated injury recovery and performance enhancement. While numerous peptide drugs have undergone a rigorous approval process that evaluates both safety and efficacy, a parallel "gray market" of unapproved compounds has emerged, operating largely outside of regulatory oversight. Our objective is to present the pharmacological mechanisms, safety profiles, and regulatory status of prominent approved and unapproved peptides marketed direct to patients, including AOD-9604 (anti-obesity drug 9604), BPC-157 (body protection compound 157), CJC-1295, FS-344 (follistatin-344), GHK-Cu (glycyl-L-histidyl-L-lysine copper), ipamorelin, MOTS-C (mitochondrial ORF of the 12S rRNA type-c), sermorelin, SS-31 (elamipretide), tesamorelin (Egrifta), Tβ4 (thymosin beta-4), and TB-500 (thymosin beta-4 fragment). Many unapproved peptides demonstrate favorable tissue repair and metabolic outcomes in animal models, but rigorous human safety data are scarce, and there is potential for serious harm to patients. This narrative review focuses on the utilization of peptides in sports medicine, and alternative treatments that may be considered. We provide a framework to navigate patient discussions about peptides to better facilitate evidence-based practices for musculoskeletal healing and athletic performance. We also discuss the placebo effect as a mediator of peptide efficacy, and how social media amplifies this effect.

Mitochondrial derived peptide MOTS-c prevents the development of heart failure under pressure overload conditions in mice.

MOTS-c, a mitochondrial-derived peptide (MDP), has been shown to have multiple biological activities such as antioxidation, anti-inflammation, and anti-apoptosis properties. In the present study, we aimed at evaluating the therapeutic effect of MOTS-c peptide in an animal model of heart failure. The heart failure mouse model was made by transverse aortic constriction (TAC) operations. The MOTS-c peptide was administrated subcutaneously by using an osmotic pump. At the end of the animal experiment, cardiac function was evaluated by echocardiography, and heart tissues were subjected to histological and molecular analysis. In vitro cultured H9C2 cells were used to test the effects of MOTS-c overexpression on cell death in response to H2 O2 stimulation. Our study showed that MOTS-c peptide attenuated TAC-induced cardiac dysfunction and remodelling. In addition, the MOTS-c peptide reduced the inflammatory response and upregulated the antioxidant capacity, coupled with the activation of the AMPK pathway in the heart of the TAC mouse model. In in vitro cultured cardiac cells, overexpression of MOTS-c was shown to activate the AMPK pathway and protect cell apoptosis in response to H2 O2 stimulation. Taken together, our study suggested that MOTS-c peptides may have therapeutic potential in treating HF.

MOTS-c-modified functional self-assembly peptide hydrogels enhance the activity of nucleus pulposus-derived mesenchymal stem cells of intervertebral disc degeneration.

Intervertebral disc degeneration (IDD) is characterized by oxidative-stress driven progressive apoptosis and senescence of nucleus pulposus mesenchymal stem cells (NP-MSCs). MOTS-c, a 16-amino acid peptide encoded by the mitochondrial 12S rRNA open reading frame, has emerged as a key regulator of cellular metabolism, oxidative stress, and senescence. This study investigated the therapeutic potential of MOTS-c in countering tert-butyl hydroperoxide (TBHP)-induced oxidative damage in NP-MSCs, and we developed a novel biomaterial strategy for IDD treatment.Key findings include. MOTS-c significantly attenuated TBHP-induced NP-MSC apoptosis (Annexin V+/PI&#xa0;+&#xa0;cells reduced by 48&#xa0;%, p&#xa0;<&#xa0;0.001), senescence (SA-&#x3b2;-gal&#xa0;+&#xa0;cells decreased by 52&#xa0;%, p&#xa0;<&#xa0;0.005), and ROS overproduction (35&#xa0;% reduction, p&#xa0;<&#xa0;0.0001) via activation of the AMPK/SIRT1 pathway. Pharmacological inhibition of SIRT1 abolished these protective effects, confirming pathway specificity. A sustained-release MOTS-c delivery system (RAD/RMOTS-c) was engineered by conjugating MOTS-c to the self-assembling RADA16-I peptide. The hydrogel exhibited a &#x3b2;-sheet-rich nanofibrous structure (fiber diameter: 362.6&#xa0;nm), shear-thinning rheology (viscosity: 131-217&#xa0;Pa&#xa0;s), and sustained peptide release over 7 days. RAD/RMOTS-c enhanced NP-MSC viability (1.8-fold vs. control, p&#xa0;<&#xa0;0.005) and extracellular matrix (ECM) synthesis, elevating collagen II/aggrecan expression (2.3-fold, p&#xa0;<&#xa0;0.05) while suppressing collagen I (63&#xa0;% reduction, p&#xa0;<&#xa0;0.001).In Vivo Therapeutic Validation: In a rat IDD model, RAD/RMOTS-c injection preserved disc height (DHI%: 82.4 vs. 58.7 in IDD group, p&#xa0;<&#xa0;0.001), restored T2-weighted MRI signals (1.5-fold increase, p&#xa0;<&#xa0;0.001), and reduced histological degeneration scores by 44&#xa0;% compared to untreated controls (p&#xa0;<&#xa0;0.001). This work (1) demonstrates the association between MOTS-c's anti-degenerative effects and AMPK/SIRT1 signaling in NP-MSCs and (2) pioneers a peptide-hydrogel hybrid system that synergistically combines mitochondrial protection with structural support for disc regeneration. The findings can advance IDD therapy toward biology-driven, minimally invasive solutions, aligning with the paradigm of functional biomaterials for degenerative diseases.

A mitochondrial-derived peptide MOTS-c contributes to the protective effect against brain injury associated with LPS-induced sepsis by strengthening the blood-brain barrier's ultrastructure.

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. A mouse model of sepsis was established via intraperitoneal injection of LPS. The mice were divided into four groups: Control, Control&#x2009;+&#x2009;MOTS-c, LPS, and LPS&#x2009;+&#x2009;MOTS-c groups. The mice in the latter two groups received MOTS-c (20&#x2009;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. 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/PDGFR&#x3b2;, decreased the expression of GFAP/Iba-1/MMP-9, and increased the expression of neurotrophic factors in septic mice. 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.

MOTS-c: A Mitochondrial-Encoded Regulator of the Nucleus.

Mitochondria are increasingly being recognized as information hubs that sense cellular changes and transmit messages to other cellular components, such as the nucleus, the endoplasmic reticulum (ER), the Golgi apparatus, and lysosomes. Nonetheless, the interaction between mitochondria and the nucleus is of special interest because they both host part of the cellular genome. Thus, the communication between genome-bearing organelles would likely include gene expression regulation. Multiple nuclear-encoded proteins have been known to regulate mitochondrial gene expression. On the contrary, no mitochondrial-encoded factors are known to actively regulate nuclear gene expression. MOTS-c (mitochondrial open reading frame of the 12S ribosomal RNA type-c) is a recently identified peptide encoded within the mitochondrial 12S ribosomal RNA gene that has metabolic functions. Notably, MOTS-c can translocate to the nucleus upon metabolic stress (e.g., glucose restriction and oxidative stress) and directly regulate adaptive nuclear gene expression to promote cellular homeostasis. It is hypothesized that cellular fitness requires the coevolved mitonuclear genomes to coordinate adaptive responses using gene-encoded factors that cross-regulate the opposite genome. This suggests that cellular gene expression requires the bipartite split genomes to operate as a unified system, rather than the nucleus being the sole master regulator.

Mitochondrial-Derived Peptide MOTS-c Ameliorates Spared Nerve Injury-Induced Neuropathic Pain in Mice by Inhibiting Microglia Activation and Neuronal Oxidative Damage in the Spinal Cord via the AMPK Pathway.

MOTS-c, a recently discovered mitochondrial-derived peptide, plays an important role in many physiological and pathological functions via adenosine monophosphate-activated protein kinase (AMPK) activation. Numerous studies have demonstrated that AMPK is an emerging target for the modulation of neuropathic pain. Meanwhile, microglia-activation-evoked neuroinflammation is known to contribute to the development and progression of neuropathic pain. MOTS-c is also known to inhibit microglia activation, chemokine and cytokine expression, and innate immune responses. Accordingly, in this study, we evaluated the effects of MOTS-c on neuropathic pain and investigated the putative underlying mechanisms. We found that MOTS-c levels in plasma and spinal dorsal horn were significantly lower in mice with spared nerve injury (SNI)-induced neuropathic pain than in control animals. Accordingly, MOTS-c treatment produced pronounced dose-dependent antinociceptive effects in SNI mice; however, these effects were blocked by dorsomorphin, an AMPK inhibitor, but not naloxone, a nonselective opioid receptor antagonist. Moreover, intrathecal (i.t.) injection of MOTS-c significantly enhanced AMPK&#x3b1;1/2 phosphorylation in the lumbar spinal cord of SNI mice. MOTS-c also significantly inhibited proinflammatory cytokine production and microglia activation in the spinal cord. The antinociceptive effects of MOTS-c were retained even when microglia activation in the spinal cord was inhibited by minocycline pretreatment, indicating that spinal cord microglia are dispensable for the antiallodynic effects of MOTS-c. In the spinal dorsal horn, MOTS-c treatment inhibited c-Fos expression and oxidative damage mainly in neurons rather than microglia. Finally, in contrast to morphine, i.t. administration of MOTS-c resulted in limited side effects relating to antinociceptive tolerance, gastrointestinal transit inhibition, locomotor function, and motor coordination. Collectively, the present study is the first to provide evidence that MOTS-c may be a promising therapeutic target for neuropathic pain.

The protective effect of the mitochondrial-derived peptide MOTS-c on LPS-induced septic cardiomyopathy.

Septic cardiomyopathy is associated with mechanisms such as excessive inflammation, oxidative stress, regulation of calcium homeostasis, endothelial dysfunction, mitochondrial dysfunction, and cardiomyocyte death, and there is no effective treatment at present. MOTS-c is a mitochondria-derived peptide (MDP) encoded by mitochondrial DNA (mtDNA) that protects cells from stresses in an AMPK-dependent manner. In the present study, we aim to explore the protective effect of MOTS-c on lipopolysaccharide (LPS)-induced septic cardiomyopathy. LPS is used to establish a model of septic cardiomyopathy. Our results demonstrate that MOTS-c treatment reduces the mRNA levels of inflammatory cytokines ( IL-1&#x3b2;, IL-4, IL-6, and TNF&#x3b1;) in cardiomyocytes and the levels of circulating myocardial injury markers, such as CK-MB and TnT, alleviates cardiomyocyte mitochondrial dysfunction and oxidative stress, reduces cardiomyocyte apoptosis, activates cardioprotection-related signaling pathways, including AMPK, AKT, and ERK, and inhibits the inflammation-related signaling pathways JNK and STAT3. However, treatment with the AMPK pathway inhibitor compound C (CC) abolishes the positive effect of MOTS-c on LPS stress. Collectively, our research suggests that MOTS-c may attenuate myocardial injury in septic cardiomyopathy by activating AMPK and provides a new idea for therapeutic strategies in septic cardiomyopathy.

The Mitochondrial-Derived Peptide (MOTS-c) Interacted with Nrf2 to Defend the Antioxidant System to Protect Dopaminergic Neurons Against Rotenone Exposure.

MOTS-c is a 16-amino acid mitochondrial-derived peptide reported to be involved in regulating energy metabolism. However, few studies have reported the role of MOTS-c on neuron degeneration. In this study, it was aimed to explore the action of MOTS-c in rotenone-induced dopaminergic neurotoxicity. In an in vitro study, it was observed that rotenone could influence the expression and localization of MOTS-c significantly in PC12 cells, with more MOTS-c translocating into the nucleus from mitochondria. Further study showed that the translocation of MOTS-c from the mitochondria into the nucleus could directly interact with Nrf2 to regulate HO-1 and NQO1 expression in PC12 cells exposed to rotenone, which had been suggested to be involved in the antioxidant defense system. In vivo and in vitro experiments demonstrated that exogenous MOTS-c pretreatment could protect PC12 cells and rats from mitochondrial dysfunction and oxidative stress induced by rotenone. Moreover, MOTS-c pretreatment significantly decreased the loss of TH, PSD95, and SYP protein expression in the striatum of rats exposed to rotenone. In addition, MOTS-c pretreatment could clearly alleviate the downregulated expression of Nrf2, HO-1, and NQO1, as well as the upregulated Keap1 protein expression in the striatum of rotenone-treated rats. Taken together, these findings suggested that MOTS-c could directly interact with Nrf2 to activate the Nrf2/HO-1/NQO1 signal pathway to defend the antioxidant system to prevent dopaminergic neurons from rotenone-induced oxidative stress and neurotoxicity in vitro and in vivo.

MOTS-c: Magical Molecule for Diabetic Cardiomyopathy?

Mitochondrial-derived peptides in cardiovascular disease: Novel insights and therapeutic opportunities.

Mitochondria-derived peptides (MDPs) represent a recently discovered family of peptides encoded by short open reading frames (ORFs) found within mitochondrial genes. This group includes notable members including humanin (HN), mitochondrial ORF of the 12S rDNA type-c (MOTS-c), and small humanin-like peptides 1-6 (SHLP1-6). MDPs assume pivotal roles in the regulation of diverse cellular processes, encompassing apoptosis, inflammation, and oxidative stress, which are all essential for sustaining cellular viability and normal physiological functions. Their emerging significance extends beyond this, prompting a deeper exploration into their multifaceted roles and potential applications. This review aims to comprehensively explore the biogenesis, various types, and diverse functions of MDPs. It seeks to elucidate the central roles and underlying mechanisms by which MDPs participate in the onset and development of cardiovascular diseases (CVDs), bridging the connections between cell apoptosis, inflammation, and oxidative stress. Furthermore, the review highlights recent advancements in clinical research related to the utilization of MDPs in CVD diagnosis and treatment. MDPs levels are diminished with aging and in the presence of CVDs, rendering them potential new indicators for the diagnosis of CVDs. Also, MDPs may represent a novel and promising strategy for CVD therapy. In this review, we delve into the biogenesis, various types, and diverse functions of MDPs. We aim to shed light on the pivotal roles and the underlying mechanisms through which MDPs contribute to the onset and advancement of CVDs connecting cell apoptosis, inflammation, and oxidative stress. We also provide insights into the current advancements in clinical research related to the utilization of MDPs in the treatment of CVDs. This review may provide valuable information with MDPs for CVD diagnosis and treatment.

Mitochondrial-Derived Peptides in Diabetes and Its Complications.

The changes of mitochondrial function are closely related to diabetes and its complications. Here we describe the effects of mitochondrial-derived peptides (MDPs), short peptides formed by transcription and translation of the open reading frame site in human mitochondrial DNA (mtDNA), on diabetes and its complications. We mainly focus on MDPs that have been discovered so far, such as Humanin (HN), mitochondrial open reading frame of the 12S rRNA-c (MOTS-c) and Small humanin-like peptides (SHLP 1-6), and elucidated the role of MDPs in diabetes and its major complications stroke and myocardial infarction by improving insulin resistance, inhibiting inflammatory response and anti-apoptosis. It provides more possibilities for the clinical application of mitochondrial derived peptides.

Reduced serum levels of mitochondria-derived peptide MOTS-c in patients with obstructive sleep apnea.

Recent research has identified the mitochondrial open reading frame of the 12S rRNA-c (MOTS-c) as a crucial mitochondrial peptide that significantly influences metabolic regulation, mimics the effects of exercise, and mitigates oxidative stress. This study aims to investigate the relationship between serum MOTS-c levels and obstructive sleep apnea (OSA) to enhance our understanding of the disease's pathophysiology. By elucidating this relationship, we hope to uncover new insights into the mechanisms underlying OSA and its associated metabolic complications. Seventy-seven participants were enrolled in this study, including 53 patients with OSA and 24 controls. We measured serum MOTS-c levels and collected participants' demographic characteristics, polysomnography (PSG) data, complete blood count (CBC) data, and sleep-related questionnaires. The study included 77 participants, consisting of 8 patients with mild OSA, 16 with moderate OSA, 29 with severe OSA, and 24 controls. The cohort comprised 26 women and 51 men. Analysis revealed that serum MOTS-c levels were significantly correlated with BMI, AHI (Apnea-Hypopnea Index), and ODI (Oxygen Desaturation Index), independent of age. Additionally, the severity of OSA was inversely related to serum MOTS-c levels, with lower levels observed in patients with more severe OSA. Variations in serum MOTS-c levels were also noted across different BMI classifications. Analysis of covariance (ANCOVA), with BMI as a covariate, demonstrated that the severity of OSA was an independent factor influencing serum MOTS-c levels. Serum MOTS-c levels correlate with both severity of OSA and BMI classification, suggesting that MOTS-c may have significant therapeutic potential for treating OSA.

Exercise, Mitohormesis, and Mitochondrial ORF of the 12S rRNA Type-C (MOTS-c).

Low levels of mitochondrial stress are beneficial for organismal health and survival through a process known as mitohormesis. Mitohormetic responses occur during or after exercise and may mediate some salutary effects of exercise on metabolism. Exercise-related mitohormesis involves reactive oxygen species production, mitochondrial unfolded protein response (UPRmt), and release of mitochondria-derived peptides (MDPs). MDPs are a group of small peptides encoded by mitochondrial DNA with beneficial metabolic effects. Among MDPs, mitochondrial ORF of the 12S rRNA type-c (MOTS-c) is the most associated with exercise. MOTS-c expression levels increase in skeletal muscles, systemic circulation, and the hypothalamus upon exercise. Systemic MOTS-c administration increases exercise performance by boosting skeletal muscle stress responses and by enhancing metabolic adaptation to exercise. Exogenous MOTS-c also stimulates thermogenesis in subcutaneous white adipose tissues, thereby enhancing energy expenditure and contributing to the anti-obesity effects of exercise training. This review briefly summarizes the mitohormetic mechanisms of exercise with an emphasis on MOTS-c.

Lipids and insulin regulate mitochondrial-derived peptide (MOTS-c) in PCOS and healthy subjects.

Polycystic ovarian syndrome (PCOS) is a heterogeneous endocrine disorder associated with mitochondrial dysfunction and insulin resistance (IR). MOTS-c, a mitochondrial peptide, promotes insulin sensitivity (IS) through activating AKT and AMPK-dependent pathways. The current study was designed to examine the response of MOTS-c to lipids (intralipid) followed by insulin in PCOS and healthy subjects. All subjects underwent 5-hour intralipid/saline infusion with a hyperinsulinemic-euglycaemic clamp in the final 2&#xa0;hours. Plasma samples were collected to measure circulating MOTS-c using a commercial ELISA kit. Subsequently, this was repeated following an eight-week exercise intervention. Intralipid significantly increased plasma MOTS-c both in controls and PCOS subjects, whilst the insulin infusion blunted the intralipid-induced response seen for both lipids and MOT-c. Intralipid elevated plasma MOTS-c to 232&#xa0;&#xb1;&#xa0;124% of basal in control (P&#xa0;<&#xa0;0.01) and to 349&#xa0;&#xb1;&#xa0;206% of basal in PCOS (P&#xa0;<&#xa0;0.001) subjects. Administration of insulin suppressed intralipid-induced MOTS-c from 232&#xa0;&#xb1;&#xa0;124% to 165&#xa0;&#xb1;&#xa0;97% (NS) in control and from 349&#xa0;&#xb1;&#xa0;206% to 183&#xa0;&#xb1;&#xa0;177% (P&#xa0;<&#xa0;0.05) in PCOS subjects, respectively. Following exercise, intralipid elevated plasma MOTS-c to 305&#xa0;&#xb1;&#xa0;153% of basal in control (P&#xa0;<&#xa0;0.01) and to 215&#xa0;&#xb1;&#xa0;103% of basal in PCOS (P&#xa0;<&#xa0;0.01) subjects; insulin suppressed intralipid-induced MOTS-c only in controls. In conclusion, this is the first study to show increased lipid enhanced circulating MOTS-c whilst insulin attenuated the MOTS-c response in human. Further, eight weeks of moderate exercise training did not show any changes in circulating MOTS-c levels in healthy controls and in women with PCOS.

The mitochondrial-derived peptide MOTS-c: a player in exceptional longevity?

Mitochondrial-derived peptides (MDP) are encoded by functional short open reading frames in the mitochondrial DNA (mtDNA). These include humanin, and the recently discovered mitochondrial open reading frame of the 12S rRNA-c (MOTS-c). Although more research is needed, we suggest that the m.1382A>C polymorphism located in the MOTS-c encoding mtDNA, which is specific for the Northeast Asian population, may be among the putative biological mechanisms explaining the high longevity of Japanese people.