Orally administered MOTS-c analogue ameliorates dextran sulfate sodium-induced colitis by inhibiting inflammation and apoptosis

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.

Central and peripheral mechanism of MOTS-c attenuates pain hypersensitivity in a mice model of inflammatory pain

BACKGROUND

Inflammatory pain is caused by damaged tissue or noxious stimuli, accompanied by the release of inflammatory mediators that often leads to severe hyperalgesia and allodynia with limited therapy options. Recently, a novel mitochondrial-derived peptide (named MOTS-c) was reported to regulate obesity, metabolic homeostasis and inflammatory response. The aim of this study was to investigate the effects of MOTS-c and its related regulatory mechanisms involved in inflammatory pain.

METHODS

Male Kunming mice (8-10 weeks-old) were intraplantar injected with formalin, capsaicin, λ-Carrageenan and complete Freund adjuvant (CFA) to establish acute and chronic inflammatory pain. The effects of MOTS-c on the above inflammatory pain mice and its underlying mechanisms were examined by behavioral tests, quantitative polymerase chain reaction (qPCR), western blotting, enzyme linked immunosorbent assay (ELISA), immunohistochemistry (IHC) and immunofluorescence (IF).

RESULTS

Behavioral experiments investigated the potential beneficial effects of MOTS-c on multiple acute and chronic inflammatory pain in mice. The results showed that MOTS-c treatment produced potent anti-allodynic effects in formalin-induced acute inflammatory pain, capsaicin-induced nocifensive behaviors and λ-Carrageenan/CFA-induced chronic inflammatory pain model. Further mechanistic studies revealed that central MOTS-c treatment significantly ameliorated CFA-evoked the release of inflammatory factors and activation of glial cells and neurons in the spinal dorsal horn. Moreover, peripheral MOTS-c treatment reduced CFA-evoked inflammatory responses in the surface structure of hindpaw skin, accompanied by inhibiting excitation of peripheral calcitonin gene-related peptide (CGRP) and P2X3 nociceptive neurons.

CONCLUSIONS

The present study indicates that MOTS-c may serve as a promising therapeutic target for inflammatory pain.

The Role of AMPK Signaling in Ulcerative Colitis

Ulcerative colitis (UC) is a chronic non-specific inflammatory bowel disease characterized by inflammation and ulcer formation of the intestinal mucosa. Due to its high recurrence rate, prolonged course, limited curative options, and significant impact on patients' quality of life, along with a notable potential for malignant transformation, UC is designated as a refractory global health challenge by the World Health Organization (WHO). The elucidation of the pathogenesis and therapeutic strategies for UC requires further in-depth investigation. AMP-activated protein kinase (AMPK) serves as a central regulator of cellular energy metabolic homeostasis. Emerging evidence indicates that interventions involving traditional Chinese medicine (TCM) components, as well as other pharmacological measures, exert beneficial effects on the intestinal mucosal inflammation and epithelial barrier dysfunction in UC by modulating AMPK signaling, thereby influencing biological processes such as cellular autophagy, apoptosis, inflammatory responses, macrophage polarization, and NLRP3 inflammasome-mediated pyroptosis. The role of AMPK in UC is of significant importance. This manuscript provides a comprehensive overview of the mechanisms through which AMPK is involved in UC, as well as a compilation of pharmacological agents capable of activating the AMPK signaling pathway within the context of UC. The primary objective is to facilitate a deeper comprehension of the pivotal role of AMPK in UC among researchers and clinical practitioners, thereby advancing the identification of novel therapeutic targets for interventions in UC.

MOTS-c Peptide Attenuated Diabetic Cardiomyopathy in STZ-Induced Type 1 Diabetic Mouse Model

BACKGROUND

Diabetic cardiomyopathy (DCM) pathogenesis is a common complication of diabetes, but effective treatments remain limited. Mitochondrial-derived peptide MOTS-c has shown therapeutic promise in animal models of various heart diseases, but its efficacy in DCM is unknown. This study investigates the effects of MOTS-c treatment in a mouse model of type 1 diabetes-induced DCM.

METHODS

Type 1 diabetes (T1DM) was induced in mice by streptozotocin (STZ) injection. After diabetes establishment, the mice were randomly dividend into two groups treated with or without MOTS-c peptide, which was administered subcutaneously by osmotic pump for 12 weeks. At the end of the experiment, cardiac function, histology, and molecular changes were determined.

RESULTS

The results showed that diabetic mice exhibited significant cardiac dysfunction, dilatation, and adverse cardiac remodeling. MOTS-c treatment markedly ameliorated these diabetes-associated myocardial function and structure abnormalities. Additionally, MOTS-c reversed AMPK signaling deactivation and inhibited inflammation in the diabetic heart.

CONCLUSIONS

Our data demonstrated a protective effect of MOTS-c against diabetic cardiomyopathy potentially by activating the AMPK pathway and inhibiting inflammation. These findings demonstrate the therapeutic efficacy of MOTS-c for diabetic cardiomyopathy and warrant further investigation into its clinical potential.

Cell-permeable peptide-based delivery vehicles useful for subcellular targeting and beyond

Personal medicine aims to provide tailor-made diagnostics and treatments and has been emerged as a promising but challenging strategy during the last years. This includes the active delivery and localization of a therapeutic compound to a targeted site of action within a cell. An example being targeting the interference of a distinct protein-protein interaction (PPI) within the cell nucleus, mitochondria or other subcellular location. Therefore, not only the cell membrane has to be overcome but also the final intracellular destination has to be reached. One approach which fulfills both requirements is to use short peptide sequences that are able to translocate into cells as targeting and delivery vehicles. In fact, recent progress in this field demonstrates how these tools can modulate the pharmacological parameters of a drug without compromising its biological activity. Beside classical targets that are addressed by various small molecule drugs such as receptors, enzymes, or ion channels, PPIs have received increasing attention as potential therapeutic targets. Within this review, we will provide a recent update on cell-permeable peptides targeting subcellular destinations. We include chimeric peptide probes that combine cell-penetrating peptides (CPPs) and a targeting sequence, as well peptides having intrinsic cell-permeability and which are often used to target PPIs.

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.