MOTS-c

Age-related macular degeneration (AMD), the leading cause of irreversible vision loss in the US, is on the rise among the elderly. Uncontrolled mitochondria-derived peptide production from mtDNA disruption and 16S or 12S rRNA damage could worsen AMD. Our previous work has shown that Humanin G possesses cytoprotective effects in retinal pigment epithelial (RPE) cells. However, MOTS-c, a highly efficient mitochondrial peptide, has yet to be evaluated on retinal cell survival. In this study, we show that there are differences in effects between wild-type (wt-) and differentiated ARPE19 cells (diff-ARPE19), implying that the cellular differentiation status may influence how cells respond to MOTS-c. MOTS-c has dose-dependent effects on apoptosis, inflammation, and mitochondrial biogenesis in diff-ARPE19 cells. Lower doses (500 nM) have more significant impacts than 5 µM concentrations. In diff-ARPE19 cells, a lower dose of MOTS-c can reduce the negative impact of hypoxia on cellular survival and gene expression, including apoptosis (CASP3, CASP9), mitochondrial biogenesis (TFAM, PGC-1α), and metabolic sensor (AMPK). However, it had no significant effect on ROS levels or NRF1 expression, regardless of MOTS-c dose. Exposing diff-ARPE19 cells to varied MOTS-c dosages before and after therapy in a chemically induced hypoxic environment yields no extra benefits as compared to MOTS-c treatment alone. MOTS-c had different effects on the expression of genes linked with apoptosis, mitochondrial biogenesis, and antioxidant activity in AMD patients versus age-matched control cybrids. The MOTS-c peptide appears to enhance cellular metabolism and regulate gene expression, which could potentially provide therapeutic benefits in AMD.

OBJECTIVE: Hepatitis B virus (HBV) infection causes substantial harm to mitochondrial activity, which hinders the development of effective treatments for chronic hepatitis B (CHB). The discovery of the mitochondrial-derived short peptide MOTS-c, which possesses multiple bioactivities, offers a promising new approach in treating HBV infection. This study aims to explore the diagnostic and therapeutic potential of MOTS-c in HBV-related diseases and its molecular mechanism. DESIGN: In total, 85 healthy subjects and 404 patients with HBV infection, including 20 clinical treatment cohorts, were recruited for this study. MOTS-c levels were measured by ELISA and its diagnostic value was evaluated by receiving operating characteristic curve analysis. The therapeutic effect of MOTS-c was observed in multiple HBV-infected mice and cells through various techniques, including transcriptomic sequencing, flow cytometry, immunofluorescence and electron microscopy. Additionally, MOTS-c's potential interaction with myosin-9 (MYH9) and actin was predicted using immunoprecipitation, proteomics and target prediction software. RESULTS: MOTS-c negatively correlates with HBV DNA expression (R=-0.71), and its AUC (the area under the curve) for distinguishing CHB from healthy controls is 0.9530, and IA (immune reactive) from IC (inactive HBV carrier) is 0.8689. Inhibition of HBV replication (with a 50-70% inhibition rate) was observed alongside improved liver function without notable toxicity in vitro or in vivo. MOTS-c was found to promote mitochondrial biogenesis and enhance the MAVS (mitochondrial antiviral signalling protein) signalling pathway. The impact is dependent on MOTS-c's ability to regulate MYH9-actin-mediated mitochondrial homeostasis. CONCLUSION: MOTS-c has the potential to serve as a biomarker for the progression of HBV infection while also enhancing antiviral efficacy. These findings present a promising innovative approach for effectively treating patients with CHB. Furthermore, our research uncovers a novel role for MOTS-c in regulating MYH9-actin-mediated mitochondrial dynamics and contributing to mitochondrial biogenesis.

BACKGROUND: Lung and breast cancer are the most frequent causes of death from cancer globally. The objectives of this research were to evaluate the serum mitochondrial open reading frame of the 12S rRNA-c (MOTS-c) and humanin levels in lung or breast cancer patients, and investigate the impacts of radiation therapy on the circulating levels of these peptides. METHODS: 35 lung cancer patients, 34 breast cancer patients, and healthy volunteers as a control group were recruited in this prospective observatory research. Lung cancer patients with stage IIIA/IIIB were treated with paclitaxel-based chemotherapy plus radiotherapy (2 Gy per day, 30 times, 60 Gy total dose). Breast cancer stage IIA/IIB patients were treated with postoperative locoregional radiation therapy (2 Gy per day, 25 times, 50 Gy total dose). The ELISA method was used to detect serum humanin and MOTS-c levels during, before, and after radiotherapy. RESULTS: We observed marked elevations in circulating MOTS-c, but not humanin levels in patients with lung cancer (P < 0.001). Radiation therapy led to a marked augmentation in MOTS-c levels in these patients (P < 0.001). On the other hand, there was a marked decline in humanin, but not MOTS-c, levels in breast cancer patients (P < 0.001). CONCLUSION: Our research has shown, for the first time, that increased MOTS-c and decreased humanin levels play a role in lung cancer and breast cancer, respectively. Additionally, radiotherapy modifies MOTS-c levels in patients with lung, but not breast cancer.

Sodium-glucose cotransporter 2 (SGLT2) inhibitors produce cardioprotective effects on heart failure (HF), even in the absence of diabetes. However, the underlying mechanisms of this cardioprotective effect remain unexplored. The purpose of this study was to examine the effects of SGLT2 inhibitors on serum MOTS-c, humanin levels, nitrosative stress, and ferroptosis parameters in diabetic patients with HF with reduced ejection fraction (HFrEF). A total of 74 adult diabetic patients with HFrEF and 37 healthy controls were included in this prospective study. Half of the patients were using SGLT2 inhibitors (empagliflozin or dapagliflozin) for at least two months. Serum nitric oxide and 3-nitrotyrosine levels were markedly higher in diabetic patients with HFrEF than the control (P < 0.001), but these elevations were inhibited with SGLT2 inhibitors. Although SGLT2 inhibitors had no marked effect on humanin levels, they significantly augmented MOTS-c levels when compared to the control. SGLT2 inhibitors augmented GPX4 but inhibited ACSL4 levels when compared to diabetic patients with HF. However, TFRC levels were increased in the patient group (P < 0.001 for all) but not modified with SGLT2 inhibitors. Our results suggest that increased nitrosative stress is significantly depressed by SGLT2 inhibitors. This study was the first to show that SGLT2 inhibitors can stimulate MOTS-c, but not humanin, in diabetic patients with HFrEF. SGLT2 inhibitors reduced ferroptosis through elevation of GPX4 and suppression of ACSL4 levels. Our data suggest that SGLT2 inhibitors could produce cardioprotective effects through relieving ferroptosis, inhibiting nitosative stress, and stimulating mitochondrial MOTS-c release.

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.

The aim of the study was to investigate the effect of MOTS-c on the key functional alterations in the rat soleus muscle during 7-day unloading - the transformation of slow fibers into fast ones, atrophy and increased fatigue. We daily intraperitoneally injected male Wistar rats with a short mitochondrial peptide MOTS-c during 7-day unloading of their hind limbs. After the end of the experiment, we conducted an ex vivo fatigue test of soleus muscle and showed that the MOTS-c administration prevents increased fatigue during 7-day hind limb unloading. Also, using immunohistochemical analysis, we showed that MOTS-c prevents the transformation of slow fibers into fast ones, mitigates the slow muscle atrophy fibers (but not fast ones) of the soleus muscle. In the group receiving MOTS-c, the decrease in Akt and GSK3β phosphorylation was prevented, and the 18 S and 28 S rRNA levels were at the control level. The ubiquitin ligases MuRF and Atrogin-1 mRNA were also reduced compared to the hindlimb unloading group with placebo. In addition, MOTS-c prevented a decrease in the expression of a few mitochondrial biogenesis parameters and the level of ACC phosphorylation (AMPK target). Thus, the MOTS-C injections during hind limb unloading lead to the normalization of several protein synthesis and degradation processes and support the expression of genes that ensure muscle resistance to fatigue.