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

The upregulation of TNKS1 drives the phenotypic switching of vascular smooth muscle cells in aortic dissection through the activation of ferroptosis

OBJECTIVE

Aortic dissection (AD) is a life-threatening disease. Tankyrase1 (TNKS1), a PARylating ADP-ribosyl transferase, plays a major role in myogenesis, a vital process known to drive muscle fiber formation and regeneration.This study explores the impact of TNKS1 on the transformation of human aortic smooth muscle cells (HASMCs) in AD.

METHODS AND RESULTS

Single-cell RNA sequencing was performed and clusters were used for between-disease differential gene expression analyses. In the AD aorta, WB, immunofluorescence and RT-q-PCR revealed that TNKS1 expression was elevated, accompanied by a disorganized cell phenotype. Further examination like WB，immunofluorescence,Scratch-Wound Assay confirmed the upregulation of TNKS1 triggers phenotypic switching.Subsequent studies revealed that ferroptosis played a key role in TNKS1-induced phenotypic switching. Increased ferroptosis markers, such as elevated iron content,ROS and lipid peroxidation, were observed in HASMCs overexpressing TNKS1, while inhibition of ferroptosis restored the contractile phenotype.Co-IP assay demonstrated a direct protein-protein interaction between TNKS1 and SLC7A11 at the molecular level. In vivo, the upregulation of TNKS1 not only activated ferroptosis but also triggered phenotypic transformation.

CONCLUSION

This study demonstrates that TNKS1 is a key regulator of AD pathogenesis, driving HASMC phenotypic switching through ferroptosis activation, ultimately leading to aortic wall destabilization and dissection. Targeting TNKS1 or the ferroptosis pathway may offer novel therapeutic strategies for AD prevention and treatment.

Circulating Mitochondrial N-Formyl Peptides Are Associated with Acute Respiratory Distress Syndrome after Cardiopulmonary Bypass and Regulate Endothelial Barrier through FPR2

Cardiopulmonary bypass (CPB) increases the risk of acute respiratory distress syndrome (ARDS) because of endothelial cell (EC) barrier dysfunction. However, the specific role of mitochondrial N-formyl peptides (mtNFPs) in ARDS after CPB remains unexplored. Here, we investigated the differential expression of circulating mtNFPs in patients after CPB, focusing on the novel role of FPR2 (formyl-peptide receptor 2) in ECs. Concentrations of circulating mtNFPs were assessed using ELISA. Several mtNFPs (ND4 [nicotinamide adenine dinucleotide dehydrogenase subunit 4], ND5, ND6, and Cox1) were significantly upregulated in patients with ARDS at Day 1 after CPB compared with patients without ARDS. Higher concentrations of ND6 were correlated with worse ratios of arterial oxygen pressure to fraction of inspired oxygen (r = -0.2219; P < 0.0001) and cardiac troponin T (r = 2.107; P < 0.0001). Using patient-derived serum and a rat lung ischemia-reperfusion injury model, we observed a positive correlation between serum ND6 concentration and ARDS, which is also associated with EC barrier dysfunction. In vitro experiments, using transendothelial electric resistance measurements and fluorescence microscopy with FITC-labeled vascular endothelial cadherin, demonstrated that ND6 disrupts the EC barrier through FPR2. Furthermore, FPR2 controls the release of ND6 out of mitochondria and cytoplasm under hypoxia-reoxygenation. Activated FPR2 leads to the upregulation of NF-κB by inducing IκBα phosphorylation, promoting ICAM1 (intercellular cell adhesion molecule-1) and VCAM1 expression, thereby compromising EC barrier integrity. Circulating proinflammatory and barrier-disruptive mtNFPs, particularly ND6, are associated with ARDS in patients undergoing CPB. The novel ND6-FPR2 axis regulates inflammation and EC permeability through the NF-κB pathway.

New Insights into Quercetin Restoring the Impairment of Testicular Angiogenesis Induced by Silicon Dioxide Particles in Food: Inhibiting ROS/PPARγ-Mediated Ferroptosis

Silicon dioxide particles (SiO2) have been widely used in food additives. Increasing data demonstrate that SiO2 can cause multisystem damage through oxidative stress. Quercetin (Que) is one of the most popular nutritional antioxidants. Ferroptosis reduces the level of angiogenesis. However, whether Que alleviates the inhibition of testicular angiogenesis by relieving SiO2-induced ferroptosis via ROS/PPARγ is unclear. Based on this, we established SiO2-exposed mice testicular and C166 cell models and added oxidative stress activators Sanguinarine chloride (SAN), PPARγ inhibitor GW9662, and ferroptosis activator Erastin to the models in vitro. The results showed that the SiO2 exposure group had antioxidant dysfunction; PPARγ was significantly downregulated; ferroptosis levels were increased; and angiogenesis was reduced. Que treatment can alleviate these changes. The addition of SAN, GW9662, and Erastin reduced the effects of Que by activating oxidative stress, inhibiting PPARγ, and activating ferroptosis, respectively. In general, Que can alleviate SiO2-induced ferroptosis through ROS/PPARγ, thus restoring testicular angiogenesis in mice.

Ferroptosis in Cardiovascular Diseases and Ferroptosis-Related Intervention Approaches

OBJECTIVE

Cardiovascular diseases (CVDs) are major public health problems that threaten the lives and health of individuals. The article has reviewed recent progresses about ferroptosis and ferroptosis-related intervention approaches for the treatment of CVDs and provided more references and strategies for targeting ferroptosis to prevent and treat CVDs.

METHODS

A comprehensive review was conducted using the literature researches.

RESULTS AND DISCUSSION

Many ferroptosis-targeted compounds and ferroptosis-related genes may be prospective targets for treating CVDs and our review provides a solid foundation for further studies about the detailed pathological mechanisms of CVDs.

CONCLUSION

There are challenges and limitations about the translation of ferroptosis-targeted potential therapies from experimental research to clinical practice. It warrants further exploration to pursure safer and more effective ferroptosis-targeted thereapeutic approaches for CVDs.

Effects of empagliflozin and dapagliflozin on serum humanin, MOTS-c levels, nitrosative stress, and ferroptosis parameters in diabetic patients with heart failure

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.

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

BACKGROUND

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.

AIM OF REVIEW

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.

KEY SCIENTIFIC CONCEPTS OF REVIEW

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.

Relationship between ferroptosis and mitophagy in acute lung injury: a mini-review

Acute lung injury (ALI) is one of the most deadly and prevalent diseases in the intensive care unit. Ferroptosis and mitophagy are pathological mechanisms of ALI. Ferroptosis aggravates ALI, whereas mitophagy regulates ALI. Ferroptosis and mitophagy are both closely related to reactive oxygen species (ROS). Mitophagy can regulate ferroptosis, but the specific relationship between ferroptosis and mitophagy is still unclear. This study summarizes previous research findings on ferroptosis and mitophagy, revealing their involvement in ALI. Examining the functions of mTOR and NLPR3 helps clarify the connection between ferroptosis and mitophagy in ALI, with the goal of establishing a theoretical foundation for potential therapeutic approaches in the future management of ALI.

The role of FPR2-mediated ferroptosis in formyl peptide-induced acute lung injury against endothelial barrier damage and protective effect of the mitochondria-derived peptide MOTS-c

BACKGROUND

Acute lung injury (ALI) has garnered significant attention in the field of respiratory and critical care due to its high mortality and morbidity, and limited treatment options. The role of the endothelial barrier in the development of ALI is crucial. Several bacterial pathogenic factors, including the bacteria-derived formyl peptide (fMLP), have been implicated in damaging the endothelial barrier and initiating ALI. However, the mechanism by which fMLP causes ALI remains unclear. In this study, we aim to explore the mechanisms of ALI caused by fMLP and evaluate the protective effects of MOTS-c, a mitochondrial-derived peptide.

METHODS

We established a rat model of ALI and a human pulmonary microvascular endothelial cell (HPMVEC) model of ALI by treatment with fMLP. In vivo experiments involved lung histopathology assays, assessments of inflammatory and oxidative stress factors, and measurements of ferroptosis-related proteins and barrier proteins to evaluate the severity of fMLP-induced ALI and the type of tissue damage in rats. In vitro experiments included evaluations of fMLP-induced damage on HPMVEC using cell activity assays, assessments of inflammatory and oxidative stress factors, measurements of ferroptosis-related proteins, endothelial barrier function assays, and examination of the key role of FPR2 in fMLP-induced ALI. We also assessed the protective effect of MOTS-c and investigated its mechanism on the fMLP-induced ALI in vivo and in vitro.

RESULTS

Results from both in vitro and in vivo experiments demonstrate that fMLP promotes the expression of inflammatory and oxidative stress factors, activates ferroptosis and disrupts the vascular endothelial barrier, ultimately contributing to the development and progression of ALI. Mechanistically, ferroptosis mediated by FPR2 plays a key role in fMLP-induced injury, and the Nrf2 and MAPK pathways are involved in this process. Knockdown of FPR2 and inhibition of ferroptosis can attenuate ALI induced by fMLP. Moreover, MOTS-c could protect the vascular endothelial barrier function by inhibiting ferroptosis and suppressing the expression of inflammatory and oxidative stress factors through Nrf2 and MAPK pathways, thereby alleviating fMLP-induced ALI.

CONCLUSION

Overall, fMLP disrupts the vascular endothelial barrier through FPR2-mediated ferroptosis, leading to the development and progression of ALI. MOTS-c demonstrates potential as a protective treatment against ALI by alleviating the damage induced by fMLP.

PEBP4 deficiency aggravates LPS-induced acute lung injury and alveolar fluid clearance impairment via modulating PI3K/AKT signaling pathway

Acute lung injury (ALI) is a common clinical syndrome, which often results in pulmonary edema and respiratory distress. It has been recently reported that phosphatidylethanolamine binding protein 4 (PEBP4), a basic cytoplasmic protein, has anti-inflammatory and hepatoprotective effects, but its relationship with ALI remains undefined so far. In this study, we generated PEBP4 knockout (KO) mice to investigate the potential function of PEBP4, as well as to evaluate the capacity of alveolar fluid clearance (AFC) and the activity of phosphatidylinositide 3-kinases (PI3K)/serine-theronine protein kinase B (PKB, also known as AKT) signaling pathway in lipopolysaccharide (LPS)-induced ALI mice models. We found that PEBP4 deficiency exacerbated lung pathological damage and edema, and increased the wet/dry weight ratio and total protein concentration of bronchoalveolar lavage fluid (BALF) in LPS-treated mice. Meanwhile, PEBP4 KO promoted an LPS-induced rise in the pulmonary myeloperoxidase (MPO) activity, serum interleuin (IL)-1β, IL-6, and tumor necrosis factor (TNF)-α levels, and pulmonary cyclooxygenase-2 (COX-2) expression. Mechanically, PEBP4 deletion further reduced the protein expression of Na+ transport markers, including epithelial sodium channel (ENaC)-α, ENaC-γ, Na,K-ATPase α1, and Na,K-ATPase β1, and strengthened the inhibition of PI3K/AKT signaling in LPS-challenged mice. Furthermore, we demonstrated that selective activation of PI3K/AKT with 740YP or SC79 partially reversed all of the above effects caused by PEBP4 KO in LPS-treated mice. Altogether, our results indicated the PEBP4 deletion has a deterioration effect on LPS-induced ALI by impairing the capacity of AFC, which may be achieved through modulating the PI3K/AKT pathway.

Prognostic Signature Constructed of Seven Ferroptosis-Related lncRNAs Predicts the Prognosis of HBV-Related HCC

BACKGROUND

Ferroptosis and lncRNAs both play crucial roles in cancers. But the roles of ferroptosis-related lncRNAs (FRLncs) in HBV-related HCC (HBV-HCC) remain ambiguous.

METHODS

The gene expression profile and clinical data were originated from the Cancer Genome Atlas (TCGA) database. The risk signature was constructed by FRLncs based on the Cox regression analysis. The survival curve, Cox regression analysis, and time-dependent receiver operating characteristic (ROC) curve were adopted to verify the independence and reliability of the signature. A nomogram was established. Immune-infiltrating cells, immune functions, and checkpoints were analyzed.

RESULTS

A risk signature composed of 7 FRLncs (LINC00942, AC131009.1, POLH-AS1, AC090772.3, MKLN1-AS, AC009403.1, AL031985.3) was constructed and divided HBV-HCC patients into high- and low-risk groups. Patients in the high-risk group showed a poor prognosis. The area under curves (AUC) of the signature for 1-, 3-, and 5-year was satisfactory. A nomogram composed of gender, stage, age, grade, and risk signature was established. The risk signature and nomogram displayed appreciable independence and reliability in HBV-HCC patients. The T-cell CD8 + , monocyte, and macrophage M1 were expressed differently significantly in HCC patients, while macrophage M2 showed an obvious difference in the HBV-HCC patients between the different risk groups. PDCD1 and CTL4 were expressed higher in the high-risk group of HCC patients.

CONCLUSION

A 7-lncRNA signature was identified as a potential prognostic predictor for HBV-HCC patients. Immune therapy may be a promising strategy for HCC patients, especially HBV-HCC patients.

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.