Ammonium tetrathiomolybdate triggers autophagy-dependent NRF2 activation in vascular endothelial cells

Cuproptosis, a potential target for the therapy of diabetic critical limb ischemia

Diabetic patients are considered as the high risk population to develop critical limb ischemia (CLI), a peripheral vascular disease (PVD) resulted from atherosclerosis. Cuproptosis is a novel copper-dependent cell death that has shown the regulatory role in diabetes, while its effect on diabetic CLI has not been explored yet. In this study, Diabetic CLI mice was induced by femoral artery ligation (FAL) on diabetic mice. Endothelial injury in diabetic CLI was mimicked in human microvascular endothelial cells (HMEC-1) via the induction with high glucose (HG) and nutrient deprivation (ND). Besides, copper chelator Ammonium Tetrathiomolybdate (TM), which has shown the anti-cuproptosis property, was administrated to explore its potential effects on diabetic CLI mice and HG/ND-induced HMEC-1 cells. Strikingly, obvious cuproptosis was found in the gastrocnemius muscles of diabetic CLI mice and HG/ND-induced HMEC-1 cells, as evidenced by the copper overload and dysregulated cuproptosis-related proteins (such as Fe-S cluster proteins, copper exporter ATP7A, and copper importer SLC31A1). More importantly, TM protected against the hindlimb ischemic damages in diabetic CLI mice and alleviated cuproptosis-associated cell deaths in HG/ND-induced HMEC-1 cells. In summary, this study indicates the involvements of cuproptosis in diabetic CLI, and provides novel insights into copper chelator TM on diabetic CLI therapy.

Bilateral Synergistic Effects of Phototherapy-Based NIR-II Absorption Photosensitizer for Allergic Rhinitis

Allergic rhinitis (AR) is the most prevalent global health issue, affecting approximately 3 billion people, with its incidence increasing annually. The current first-line pharmacotherapy for symptom relief has limited efficacy and often results in notable side effects. Here, aza-BODIPY-based nanoparticles (RH@NPs) are developed that exhibit mild photothermal therapy (PTT) and type I photodynamic therapy (PDT) capabilities. Enhanced intramolecular charge transfer induces NIR-II absorption of the photosensitizer (RH), facilitating deeper tissue penetration for augmented AR therapy. Additionally, the use of an asymmetric donor-acceptor-acceptor' configuration promotes the self-assembly of RH, enhancing its intersystem crossing ability and enabling efficient photophysical activity. The synergistic effects of PTT (enhancing HSF1 DNA-binding activity to inhibit epithelial-mesenchymal transition by epigenetically regulating the expression of epithelial-mesenchymal transition-associated genes) and PDT (activating NRF2 transcriptional activity to stimulate the antioxidant defense system) enable RH@NPs to provide a superior therapeutic effect in a mouse model of AR. This effect is achieved by mechanically reducing the allergic response rather than merely alleviating symptoms. Notably, the photosensitizer-based physical therapy demonstrates enhanced safety. This study is the first to successfully investigate the application of phototherapy for AR and elucidate its mechanism of action, offering a novel, straightforward, and efficient treatment strategy for AR.

Bovine milk-derived extracellular vesicles reduce oxidative stress and ferroptosis induced by Klebsiella pneumoniae in bovine mammary epithelial cells

BACKGROUND

Ferroptosis is characterized by increased production of reactive oxygen species (ROS) and membrane lipid peroxidation that can exacerbate inflammatory damage. Extracellular vesicles (EVs) isolated from bovine milk have many biological functions, including antioxidant properties. However, the role of EVs on Klebsiella pneumoniae-induced ferroptosis and oxidative stress in bovine mammary epithelial cells (bMECs) and murine mammary tissue is unclear. In this study, EVs were isolated from bovine colostrum, mature milk and clinical mastitis milk (defined as C-EVs, M-EVs and CM-EVs, respectively) and assessed by transmission electron microscopy, Western blot and transcriptome sequencing. Effects of EVs on K. pneumoniae-induced ferroptosis and oxidative stress in bMECs were evaluated with immunofluorescence and Western blot.

RESULTS

In bMECs, infection with K. pneumoniae induced oxidative stress, decreasing protein expression of Nrf2, Keap1 and HO-1 plus SOD activity, and increasing ROS concentrations. However, protein expression of GPX4, ACSL4 and S100A4 in bMECs, all factors that regulate ferroptosis, was downregulated by K. pneumoniae. Furthermore, this bacterium compromised tight junctions in murine mammary tissue, with low expression of ZO-1 and Occludin, whereas protein expression of Nrf2 and GPX4 was also decreased in mammary tissue. Adding C-EVs, M-EVs or CM-EVs reduced oxidative stress and ferroptosis in K. pneumoniae-infected bMECs in vitro and murine mammary tissues in vivo.

CONCLUSION

In conclusion, all 3 sources of milk-derived EVs alleviated oxidative stress and ferroptosis in K. pneumoniae-infected bMECs and mammary tissues.

N6-methyladenosine demethylase FTO regulates neuronal oxidative stress via YTHDC1-ATF3 axis in arsenic-induced cognitive dysfunction

Excessive exposure to metals in daily life has been proposed as an environmental risk factor for neurological disorders. Oxidative stress is an inevitable stage involved in the neurotoxic effects induced by metals, nevertheless, the underlying mechanisms are still unclear. In this study, we used arsenic as a representative environmental heavy metal to induce neuronal oxidative stress and demonstrated that both in vitro and in vivo exposure to arsenic significantly increased the level of N6-methyladenosine (m6A) by down-regulating its demethylase FTO. Importantly, the results obtained from FTO transgenic mice and FTO overexpressed/knockout cells indicated that FTO likely regulated neuronal oxidative stress by modulating activating transcription factor 3 (ATF3) in a m6A-dependent manner. We also identified the specific m6A reader protein, YTHDC1, which interacted with ATF3 and thereby affecting its regulatory effects on oxidative stress. To further explore potential intervention strategies, cerebral metabolomics was conducted and we newly identified myo-inositol as a metabolite that exhibited potential in protecting against arsenic-induced oxidative stress and cognitive dysfunction. Overall, these findings provide new insights into the importance of the FTO-ATF3 signaling axis in neuronal oxidative stress from an m6A perspective, and highlight a beneficial metabolite that can counteract the oxidative stress induced by arsenic.

Copper mediated follicular atresia: Implications for granulosa cell death

3-nitropropanoic acid is a potent oxidative stress inducer that is conventionally regarded as a regulator of follicular atresia by regulating granulosa cells (GCs) death through the apoptosis pathway. There has been no research investigating the impact of copper metal overload induced Cuproptosis in ovarian GCs as a factor contributing to hindered follicular development.To elucidate whether 3-NP-induced oxidative stress plays a contributory role in promoting Cuproptosis, and discuss the role of Cuproptosis in the development of ovarian follicles.We conducted an analysis of cuproptosis occurrence in murine GCs and C57BL/6 J mice under the influence of 3-NP and 3-NP with added exogenous copper.The results revealed that 3-NP serving as a robust facilitator of exogenous copper uptake by upregulating the expression of copper transporter 1 (CTR1). In turn, culminated in the accumulation of intracellular copper within mouse granulosa cells (mGCs). Furthermore, 3-NP promoted mitochondrial permeability transition pore opening and concurrently reduced the stability of lipoic acid proteins. These actions collectively induced the oligomerization of Dihydrolipoamide S-Acetyltransferase (DLAT), ultimately leading to cuproptosis in GCs and consequent follicular atresia. Heavy metal copper and fungal decomposition product 3-NP, induce ovarian atresia via cuproptosis, modulating the reproductive performance of female animals.

Nrf2 Connects Cellular Autophagy and Vascular Senescence in Atherosclerosis: A Mini-Review

Nuclear factor erythroid 2-related factor 2 (Nrf2), a transcriptional factor that maintains intracellular redox equilibrium, modulates the expression of antioxidant genes, scavenger receptors, and cholesterol efflux transporters, all of which contribute significantly to foam cell development and plaque formation. Nrf2 has recently emerged as a key regulator that connects autophagy and vascular senescence in atherosclerosis. Autophagy, a cellular mechanism involved in the breakdown and recycling of damaged proteins and organelles, and cellular senescence, a state of irreversible growth arrest, are both processes implicated in the pathogenesis of atherosclerosis. The intricate interplay of these processes has received increasing attention, shedding light on their cumulative role in driving the development of atherosclerosis. Recent studies have revealed that Nrf2 plays a critical role in mediating autophagy and senescence in atherosclerosis progression. Nrf2 activation promotes autophagy, which increases lipid clearance and prevents the development of foam cells. Meanwhile, the activation of Nrf2 also inhibits cellular senescence by regulating the expression of senescence markers to preserve cellular homeostasis and function and delay the progression of atherosclerosis. This review provides an overview of the molecular mechanisms through which Nrf2 connects cellular autophagy and vascular senescence in atherosclerosis. Understanding these mechanisms can provide insights into potential therapeutic strategies targeting Nrf2 to modulate cellular autophagy and vascular senescence, thereby preventing the progression of atherosclerosis.

Sleep fragmentation exacerbates myocardial ischemia‒reperfusion injury by promoting copper overload in cardiomyocytes

Sleep disorders increase the risk and mortality of heart disease, but the brain-heart interaction has not yet been fully elucidated. Cuproptosis is a copper-dependent type of cell death activated by the excessive accumulation of intracellular copper. Here, we showed that 16 weeks of sleep fragmentation (SF) resulted in elevated copper levels in the male mouse heart and exacerbated myocardial ischemia-reperfusion injury with increased myocardial cuproptosis and apoptosis. Mechanistically, we found that SF promotes sympathetic overactivity, increases the germination of myocardial sympathetic nerve terminals, and increases the level of norepinephrine in cardiac tissue, thereby inhibits VPS35 expression and leads to impaired ATP7A related copper transport and copper overload in cardiomyocytes. Copper overload further leads to exacerbated cuproptosis and apoptosis, and these effects can be rescued by excision of the sympathetic nerve or administration of copper chelating agent. Our study elucidates one of the molecular mechanisms by which sleep disorders aggravate myocardial injury and suggests possible targets for intervention.

Fructose aggravates copper-deficiency-induced cardiac remodeling by inhibiting SERCA2a

OBJECTIVES

Accumulating evidence demonstrates that copper deficiency (CuD) is a risk factor for cardiovascular diseases, besides, fructose has been strongly linked to the development of cardiovascular diseases. However, how CuD or fructose causes cardiovascular diseases is not clearly delineated. The present study aims to investigate the mechanism of CuD or fructose on cardiac remodeling.

METHODS

We established a model of CuD- or fructose-induced cardiac hypertrophy in 3-week-old male Sprague-Dawley (SD) rats by CuD diet supplemented with or without 30% fructose for 4 weeks. In vitro study was performed by treating cardiomyocytes with tetrathiomolydbate (TM) and fructose. Echocardiography, histology analysis, immunofluorescence, western blotting, and qPCR were performed.

KEY FINDINGS

Our findings revealed that CuD caused noticeable cardiac hypertrophy either in the presence or absence of fructose supplement. Fructose exacerbated CuD-induced cardiac remodeling and intramyocardial lipid accumulation. Furthermore, we presented that the inhibition of autophagic flux caused by Ca2+ disturbance is the key mechanism by which CuD- or fructose-induced cardiac remodeling. The reduced expression of sarcoplasmic/endoplasmic reticulum Ca2+ ATPase 2a (SERCA2a) in cardiomyocytes accounts for the elevated cytoplasmic Ca2+ concentration.

CONCLUSIONS

Collectively, our study suggested that fructose aggravated CuD-induced cardiac remodeling through the blockade of autophagic flux via SERCA2a decreasing-induced Ca2+ imbalance.

Disulfidptosis, A Novel Cell Death Pathway: Molecular Landscape and Therapeutic Implications

Programmed cell death is pivotal for several physiological processes, including immune defense. Further, it has been implicated in the pathogenesis of developmental disorders and the onset of numerous diseases. Multiple modes of programmed cell death, including apoptosis, pyroptosis, necroptosis, and ferroptosis, have been identified, each with their own unique characteristics and biological implications. In February 2023, Liu Xiaoguang and his team discovered "disulfidptosis," a novel pathway of programmed cell death. Their findings demonstrated that disulfidptosis is triggered in glucose-starved cells exhibiting high expression of a protein called SLC7A11. Furthermore, disulfidptosis is marked by a drastic imbalance in the NADPH/NADP+ ratio and the abnormal accumulation of disulfides like cystine. These changes ultimately lead to the destabilization of the F-actin network, causing cell death. Given that high SLC7A11 expression is a key feature of certain cancers, these findings indicate that disulfidptosis could serve as the basis of innovative anti-cancer therapies. Hence, this review delves into the discovery of disulfidptosis, its underlying molecular mechanisms and metabolic regulation, and its prospective applications in disease treatment.

ATG5 Knockdown Attenuates Ischemia‒Reperfusion Injury by Reducing Excessive Autophagy-Induced Ferroptosis

Autophagy has been described to be both protective and pathogenic in cerebral ischemia/reperfusion (I/R) injury. The underlying association between autophagy and ferroptosis in ischemic stroke has not yet been clearly investigated. The purpose of this study was to explore the role of autophagy-related gene 5 (ATG5) in experimental ischemic stroke. After injection of ATG5 shRNA lentivirus, mice underwent surgery for transient middle cerebral artery occlusion (MCAO)-induced focal cerebral ischemia. The infarct volume, neurological function, apoptosis, reactive oxygen species (ROS), autophagy, and ferroptosis levels were evaluated. After MCAO, ATG5-knockdown mice had a smaller infarct size and fewer neurological deficits than wild-type mice. The levels of apoptosis and ROS in ischemic mouse brains were alleviated through ATG5 knockdown. The expression of LC3 I/II was reduced through ATG5 knockdown after MCAO. Additionally, the expression of beclin1 and LC3 II was increased after I/R, but the increase was counteracted by preconditioning with ATG5 knockdown. After ischemic stroke, the levels of Fe2+ and malondialdehyde (MDA) were increased, but they were reduced by ATG5 knockdown. Similarly, the expression of glutathione peroxidase 4 (GPX4) and glutathione (GSH) was decreased by I/R but elevated by ATG5 knockdown. The present study shows that ATG5 knockdown attenuates autophagy-induced ferroptosis, which may offer a novel potential approach for ischemic stroke treatment.

Ferritinophagy Mediated by Oxidative Stress-Driven Mitochondrial Damage Is Involved in the Polystyrene Nanoparticles-Induced Ferroptosis of Lung Injury

Nanoplastics are a common type of contaminant in the air. However, no investigations have focused on the toxic mechanism of lung injury induced by nanoplastic exposure. In the present study, polystyrene nanoplastics (PS-NPs) caused ferroptosis in lung epithelial cells, which could be alleviated by ferrostatin-1, deferoxamine, and N-acetylcysteine. Further investigation found that PS-NPs disturbed mitochondrial structure and function and triggered autophagy. Mechanistically, oxidative stress-derived mitochondrial damage contributed to ferroptosis, and autophagy-dependent ferritinophagy was a pivotal intermediate link, resulting in ferritin degradation and iron ion release. Furthermore, inhibition of ferroptosis using ferrostatin-1 alleviated pulmonary and systemic toxicity to reverse the mouse lung injury induced by PS-NPs inhalation. Most importantly, the lung-on-a-chip was further used to clarify the role of ferroptosis in the PS-NPs-induced lung injury by visualizing the ferroptosis, oxidative stress, and alveolar-capillary barrier dysfunction at the organ level. In summary, our study indicated that ferroptosis was an important mechanism for nanoplastics-induced lung injury through different lung cells, mouse inhalation models, and three-dimensional-based lung-on-a-chip, providing an insightful reference for pulmonary toxicity assessment of nanoplastics.

Ammonium tetrathiomolybdate relieves oxidative stress in cisplatin-induced acute kidney injury via NRF2 signaling pathway

Cisplatin is an efficient chemotherapeutic agent for various solid tumors, but its usage is restricted by nephrotoxicity. A single dose of cisplatin can cause acute kidney injury (AKI), which is characterized by rapid reduction in kidney function. However, the current therapies, such as hydration, are limited. It is vital to develop novel therapeutic reagents that have both anticancer and renoprotective properties. The objective of this study was to determine whether ammonium tetrathiomolybdate (TM), a copper chelator used to treat cancer and disorders of copper metabolism, may offer protection against cisplatin-induced AKI. In this study, we demonstrated that TM treatment had antioxidative effects and mitigated cisplatin-induced AKI both in vivo and in vitro. Mechanically, TM inhibited NRF2 ubiquitination, which activated the NRF2 pathway in HK-2 cells and promoted the expression of target genes. It should be noted that the protective effect conferred by TM against cisplatin was compromised by the knockdown of the NRF2 gene. Furthermore, TM selectively activated the NRF2 pathways in the liver and kidney. The current study provided evidence for additional clinical applications of TM by showing that it activates NRF2 and has a favorable therapeutic impact on cisplatin-induced AKI.