Maresin-1 inhibits high glucose induced ferroptosis in ARPE-19 cells by activating the Nrf2/HO-1/GPX4 pathway

Effective protective mechanisms of HO-1 in diabetic complications: a narrative review

Diabetes mellitus is a metabolic disorder with persistent hyperglycemia caused by a variety of underlying factors. Chronic hyperglycemia can lead to diverse serious consequences and diversified complications, which pose a serious threat to patients. Among the major complications are cardiovascular disease, kidney disease, diabetic foot ulcers, diabetic retinopathy, and neurological disorders. Heme oxygenase 1 (HO-1) is a protective enzyme with antioxidant, anti-inflammatory and anti-apoptotic effects, which has been intensively studied and plays an important role in diabetic complications. By inducing the expression and activity of HO-1, it can enhance the antioxidant, anti-inflammatory, and anti-apoptotic capacity of tissues, and thus reduce the degree of damage in diabetic complications. The present study aims to review the relationship between HO-1 and the pathogenesis of diabetes and its complications. HO-1 is involved in the regulation of macrophage polarization and promotes the M1 state (pro-inflammatory) towards to the M2 state (anti-inflammatory). Induction of HO-1 expression in dendritic cells inhibits them maturation and secretion of pro-inflammatory cytokines and promotes regulatory T cell (Treg cell) responses. The induction of HO-1 can reduce the production of reactive oxygen species, thereby reducing oxidative stress and inflammation. Besides, HO-1 also has an important effect in novel programmed cell death such as pyroptosis and ferroptosis, thereby playing a protective role against diabetes. In conclusion, HO-1 plays a significant role in the occurrence and development of diabetic complications and is closely associated with a variety of complications. HO-1 is anticipated to serve as a novel target for addressing diabetic complications, and it holds promise as a potential therapeutic agent for diabetes and its associated complications. We hope to provide inspiration and ideas for future studies in the mechanism and targets of HO-1 through this review.

BMSC-derived exosomal miR-219-5p alleviates ferroptosis in neuronal cells caused by spinal cord injury via the UBE2Z/NRF2 pathway

OBJECTIVE

The aim of this study was to investigate the molecular mechanism of exosomal miR-219-5p derived from bone marrow mesenchymal stem cells (BMSCs) in the treatment of spinal cord injury (SCI).

METHODS

Basso Beattie Bresnahan (BBB) score and tissue staining were used to assess SCI and neuronal survival in rats. The contents of Fe2+, malondialdehyde (MDA), glutathione (GSH), and superoxide dismutase (SOD) were detected by a kit. The expression levels of ubiquitin-conjugating enzyme E2 Z (UBE2Z), nuclear factor erythroid 2-related Factor 2 (NRF2) and ferroptosis-related proteins were detected by Western blotting. In addition, the ability of BMSC-derived exosomes to inhibit ferroptosis in neuronal cells in rats with SCI was validated by in vivo injection of ferroptosis inhibitors/inducers.

RESULTS

In this study, we found that miR-219-5p-rich BMSC-derived exosomes inhibited ferroptosis in SCI rats and that the alleviating effect of BMSC-Exos on SCI was achieved by inhibiting the ferroptosis signaling pathway and that NRF2 played a key role in this process. Our study confirmed that BMSC exosome-specific delivery of miR-219-5p can target UBE2Z to regulate its stability and that overexpression of UBE2Z reverses miR-219-5p regulation of NRF2. In addition, in vivo experiments showed that BMSC exosomes alleviated ferroptosis in neuronal SCI progression, and inhibiting the expression of miR-219-5p in BMSCs reduced the alleviating effect of exosomes on ferroptosis in neuronal cells and SCI.

CONCLUSION

miR-219-5p in BMSC-derived exosomes can repair the injured spinal cord. In addition, miR-219-5p alleviates ferroptosis in neuronal cells induced by SCI through the UBE2Z/NRF2 pathway.

Resveratrol Protects Müller Cells Against Ferroptosis in the Early Stage of Diabetic Retinopathy by Regulating the Nrf2/GPx4/PTGS2 Pathway

The aim of this study was to investigate the anti-ferroptotic effect of resveratrol (RSV) on retinal Müller cells (RMCs) in the early stages of diabetic retinopathy (DR) via the nuclear factor erythroid 2-related factor 2 (Nrf2)/glutathione peroxidase 4 (GPx4)/prostaglandin-endoperoxide synthase 2 (PTGS2). The retina was obtained from normal and diabetic Sprague-Dawley rats or wild-type and Nrf2 knockout (KO) diabetic mice, with or without RSV (10 mg/kg/d) treatment for 12 weeks. RMCs transfected with or without SiNrf2 were cultured with high glucose and RSV (20 mM). The retinal neurofunctional changes were measured by electroretinogram (ERG). The retinal inner nuclear layer cell mitochondrial morphological changes were detected by transmission electron microscopy. The cell viabilities were measured by cell counting kit-8 (CCK-8) assay. The levels of Fe2+, malonic dialdehyde (MDA), and glutathione (GSH) were measured by colorimetric method. The expression of Nrf2, GPx4, and PTGS2 was detected by quantitative real-time polymerase chain reaction (qRT-PCR), western blotting, and immunocytochemistry. In vivo, RSV inhibited retinal neurofunctional changes and mitochondrial morphological changes; decreased Fe2+, MDA, and PTGS2; and increased GSH, Nrf2, and GPx4 in retina of DM rats. In vitro, RSV decreased MDA and PTGS2 and increased cell viability, GSH, Nrf2, and GPx4. In vivo and vitro, the role of Nrf2-regulated signaling pathway in anti-ferroptosis by RSV was further confirmed using Nrf2 KO mice and pre-transfected SiNrf2 in RMCs. These findings indicated that RSV is a potential therapeutic option for DR and that Nrf2/GPx4/PTGS2 plays a role in the anti-ferroptosis mechanism of RSV on RMCs.

Ferroptosis: a novel mechanism of cell death in ophthalmic conditions

Ferroptosis, a new type of programmed cell death proposed in recent years, is characterized mainly by reactive oxygen species and iron-mediated lipid peroxidation and differs from programmed cell death, such as apoptosis, necrosis, and autophagy. Ferroptosis is associated with a variety of physiological and pathophysiological processes. Recent studies have shown that ferroptosis can aggravate or reduce the occurrence and development of diseases by targeting metabolic pathways and signaling pathways in tumors, ischemic organ damage, and other degenerative diseases related to lipid peroxidation. Increasing evidence suggests that ferroptosis is closely linked to the onset and progression of various ophthalmic conditions, including corneal injury, glaucoma, age-related macular degeneration, diabetic retinopathy, retinal detachment, and retinoblastoma. Our review of the current research on ferroptosis in ophthalmic diseases reveals significant advancements in our understanding of the pathogenesis, aetiology, and treatment of these conditions.

Emerging role of ferroptosis in diabetic retinopathy: a review

BACKGROUND

Diabetic retinopathy (DR) is a significant complication of diabetes and the primary cause of blindness among working age adults globally. The development of DR is accompanied by oxidative stress, characterised by an overproduction of reactive oxygen species (ROS) and a compromised antioxidant system. Clinical interventions aimed at mitigating oxidative stress through ROS scavenging or elimination are currently available. Nevertheless, these treatments merely provide limited management over the advanced stage of the illness. Ferroptosis is a distinctive form of cell death induced by oxidative stress, which is characterised by irondependent phospholipid peroxidation.

PURPOSE

This review aims to synthesise recent experimental evidence to examine the involvement of ferroptosis in the pathological processes of DR, as well as to explicate the regulatory pathways governing oxidative stress and ferroptosis in retina.

METHODS

We systematically reviewed literature available up to 2023.

RESULTS

This review included 12 studies investigating the involvement of ferroptosis in DR.

Novel lipid mediator 7S,14R-docosahexaenoic acid: biogenesis and harnessing mesenchymal stem cells to ameliorate diabetic mellitus and retinal pericyte loss

Introduction: Stem cells can be used to treat diabetic mellitus and complications. ω3-docosahexaenoic acid (DHA) derived lipid mediators are inflammation-resolving and protective. This study found novel DHA-derived 7S,14R-dihydroxy-4Z,8E,10Z,12E,16Z,19Z-docosahexaenoic acid (7S,14R-diHDHA), a maresin-1 stereoisomer biosynthesized by leukocytes and related enzymes. Moreover, 7S,14R-diHDHA can enhance mesenchymal stem cell (MSC) functions in the amelioration of diabetic mellitus and retinal pericyte loss in diabetic db/db mice. Methods: MSCs treated with 7S,14R-diHDHA were delivered into db/db mice i.v. every 5 days for 35 days. Results: Blood glucose levels in diabetic mice were lowered by 7S,14R-diHDHA-treated MSCs compared to control and untreated MSC groups, accompanied by improved glucose tolerance and higher blood insulin levels. 7S,14R-diHDHA-treated MSCs increased insulin+ β-cell ratio and decreased glucogan+ α-cell ratio in islets, as well as reduced macrophages in pancreas. 7S,14R-diHDHA induced MSC functions in promoting MIN6 β-cell viability and insulin secretion. 7S,14R-diHDHA induced MSC paracrine functions by increasing the generation of hepatocyte growth factor and vascular endothelial growth factor. Furthermore, 7S,14R-diHDHA enhanced MSC functions to ameliorate diabetes-caused pericyte loss in diabetic retinopathy by increasing their density in retina in db/db mice. Discussion: Our findings provide a novel strategy for improving therapy for diabetes and diabetic retinopathy using 7S,14R-diHDHA-primed MSCs.