Copper - a novel stimulator of autophagy

Copper homeostasis dysregulation in respiratory diseases: a review of current knowledge

Cu is an essential micronutrient for various physiological processes in almost all human cell types. Given the critical role of Cu in a wide range of cellular processes, the local concentrations of Cu and the cellular distribution of Cu transporter proteins in the lung are essential for maintaining a steady-state internal environment. Dysfunctional Cu metabolism or regulatory pathways can lead to an imbalance in Cu homeostasis in the lungs, affecting both acute and chronic pathological processes. Recent studies have identified a new form of Cu-dependent cell death called cuproptosis, which has generated renewed interest in the role of Cu homeostasis in diseases. Cuproptosis differs from other known cell death pathways. This occurs through the direct binding of Cu ions to lipoylated components of the tricarboxylic acid cycle during mitochondrial respiration, leading to the aggregation of lipoylated proteins and the subsequent downregulation of Fe-S cluster proteins, which causes toxic stress to the proteins and ultimately leads to cell death. Here, we discuss the impact of dysregulated Cu homeostasis on the pathogenesis of various respiratory diseases, including asthma, chronic obstructive pulmonary disease, idiopathic interstitial fibrosis, and lung cancer. We also discuss the therapeutic potential of targeting Cu. This study highlights the intricate interplay between copper, cellular processes, and respiratory health. Copper, while essential, must be carefully regulated to maintain the delicate balance between necessity and toxicity in living organisms. This review highlights the need to further investigate the precise mechanisms of copper interactions with infections and immune inflammation in the context of respiratory diseases and explore the potential of therapeutic strategies for copper, cuproptosis, and other related effects.

UiO-66 nanoparticles combat influenza A virus in mice by activating the RIG-I-like receptor signaling pathway

The Influenza A virus (IAV) is a zoonotic pathogen that infects humans and various animal species. Infection with IAV can cause fever, anorexia, and dyspnea and is often accompanied by pneumonia characterized by an excessive release of cytokines (i.e., cytokine storm). Nanodrug delivery systems and nanoparticles are a novel approach to address IAV infections. Herein, UiO-66 nanoparticles (NPs) are synthesized using a high-temperature melting reaction. The in vitro and in vivo optimal concentrations of UiO-66 NPs for antiviral activity are 200 μg mL-1 and 60 mg kg-1, respectively. Transcriptome analysis revealed that UiO-66 NPs can activate the RIG-I-like receptor signaling pathway, thereby enhancing the downstream type I interferon antiviral effect. These NPs suppress inflammation-related pathways, including the FOXO, HIF, and AMPK signaling pathways. The inhibitory effect of UiO-66 NPs on the adsorption and entry of IAV into A549 cells is significant. This study presents novel findings that demonstrate the effective inhibition of IAV adsorption and entry into cells via UiO-66 NPs and highlights their ability to activate the cellular RIG-I-like receptor signaling pathway, thereby exerting an anti-IAV effect in vitro or in mice. These results provide valuable insights into the mechanism of action of UiO-66 NPs against IAV and substantial data for advancing innovative antiviral nanomedicine.

Recent Progress of Copper-Based Nanomaterials in Tumor-Targeted Photothermal Therapy/Photodynamic Therapy

Nanotechnology, an emerging and promising therapeutic tool, may improve the effectiveness of phototherapy (PT) in antitumor therapy because of the development of nanomaterials (NMs) with light-absorbing properties. The tumor-targeted PTs, such as photothermal therapy (PTT) and photodynamic therapy (PDT), transform light energy into heat and produce reactive oxygen species (ROS) that accumulate at the tumor site. The increase in ROS levels induces oxidative stress (OS) during carcinogenesis and disease development. Because of the localized surface plasmon resonance (LSPR) feature of copper (Cu), a vital trace element in the human body, Cu-based NMs can exhibit good near-infrared (NIR) absorption and excellent photothermal properties. In the tumor microenvironment (TME), Cu2+ combines with H2O2 to produce O2 that is reduced to Cu1+ by glutathione (GSH), causing a Fenton-like reaction that reduces tumor hypoxia and simultaneously generates ROS to eliminate tumor cells in conjunction with PTT/PDT. Compared with other therapeutic modalities, PTT/PDT can precisely target tumor location to kill tumor cells. Moreover, multiple treatment modalities can be combined with PTT/PDT to treat a tumor using Cu-based NMs. Herein, we reviewed and briefly summarized the mechanisms of actions of tumor-targeted PTT/PDT and the role of Cu, generated from Cu-based NMs, in PTs. Furthermore, we described the Cu-based NMs used in PTT/PDT applications.

Discussion on the Mechanism of Gandoufumu Decoction Attenuates Liver Damage of Wilson's Disease by Inhibiting Autophagy through the PI3K/Akt/mTOR Pathway Based on Network Pharmacology and Experimental Verification

Background

Gandoufumu decoction (GDFMD) is a traditional Chinese medicine that has been widely used to treat Wilson's disease (WD) liver damage patients. However, its specific molecular mechanism currently remains unclear. Autophagy as a key contributor to WD liver damage has been intensely researched in the recent years. Therefore, the aim of this present study is to explore the effect of GDFMD on autophagy in WD liver damage, and the final purpose is to provide scientific evidence for GDFMD treatment in WD liver damage.

Methods

The molecular mechanisms and autophagy-related pathways of GDFMD in the treatment of WD liver damage were predicted using network pharmacology. Copper assay kit was used to determine copper content in serum. Enzyme-linked immunosorbent assay (ELISA) was utilized to quantify serum levels of liver enzymes and oxidative stress-related indicators. Hematoxylin-eosin (HE), Masson, and Sirius red staining were used for the characterization of liver pathological changes. Transmission electron microscopy, immunofluorescence, and Western blot analyses were used to evaluate autophagy activity. The impact of the GDFMD on typical autophagy-related pathway (PI3K/Akt/mTOR pathway) molecules was also assessed via Western blot analysis.

Results

GDFMD effectively attenuated serum liver enzymes, oxidative stress, autophagy, and degree of hepatic histopathological impairment and reduced serum copper content. Through network pharmacological approaches, PI3K/Akt/mTOR pathway was identified as the typical autophagy-related pathway of GDFMD in the treatment of WD liver damage. Treatment with GDFMD activated the PI3K/Akt/mTOR pathway, an effect that was able to be counteracted by LY294002, a PI3K antagonist or Rapa (rapamycin), an autophagy inducer.

Conclusions

GDFMD imparted therapeutic effects on WD through autophagy suppression by acting through the PI3K/Akt/mTOR pathway.

A Novel Vision of Reinforcing Nanofibrous Masks with Metal Nanoparticles: Antiviral Mechanisms Investigation

Prevention of spreading viral respiratory disease, especially in case of a pandemic such as coronavirus disease of 2019 (COVID-19), has been proved impossible without considering obligatory face mask-wearing protocols for both healthy and contaminated populations. The widespread application of face masks for long hours and almost everywhere increases the risks of bacterial growth in the warm and humid environment inside the mask. On the other hand, in the absence of antiviral agents on the surface of the mask, the virus may have a chance to stay alive and be carried to different places or even put the wearers at risk of contamination when touching or disposing the masks. In this article, the antiviral activity and mechanism of action of some of the potent metal and metal oxide nanoparticles in the role of promising virucidal agents have been reviewed, and incorporation of them in an electrospun nanofibrous structure has been considered an applicable method for the fabrication of innovative respiratory protecting materials with upgraded safety levels.

Graphical Abstract

Molecular mechanisms and therapeutic effects of different vitamins and minerals in COVID-19 patients

COVID-19 is a rapidly spreading disease, which has caught the world by surprise. Millions of people suffer from illness, and the mortality rates are dramatically high. Currently, there is no specific and immediate treatment for this disease. Remedies are limited to supportive regiments and few antiviral and anti-inflammatory drugs. The lack of a definite cure for COVID-19 is the reason behind its high mortality and global prevalence. COVID-19 can lead to a critical illness with severe respiratory distress and cytokine release. Increased oxidative stress and excessive production of inflammatory cytokines are vital components of severe COVID-19. Micronutrients, metalloids, and vitamins such as iron, manganese, selenium, Zinc, Copper, vitamin A, B family, and C are among the essential and trace elements that play a pivotal role in human nutrition and health. They participate in metabolic processes that lead to energy production. In addition, they support immune functions and act as antioxidants. Therefore, maintaining an optimal level of micronutrients intake, particularly those with antioxidant activities, is essential to fight against oxidative stress, modulate inflammation, and boost the immune system. Therefore, these factors could play a crucial role in COVID-19 prevention and treatment. In this review, we aimed to summarize antiviral properties of different vitamins and minerals. Moreover, we will investigate the correlation between them and their effects in COVID-19 patients.

Identification of a prognostic model using cuproptosis-related genes in uveal melanoma

The most common intraocular malignancy in adults remains uveal melanoma (UVM), and those with metastatic disease have a poor outlook. Proliferation, angiogenesis, and metastasis of tumor cells can be triggered by cuproptosis, affecting the survival of cancer patients. Nonetheless, cuproptosis-related genes (CRGs) have not been identified in UVM. In this study, we analyzed 10 CRGs in 80 patients with UVM in the Cancer Genome Atlas (TCGA) database regarding the alterations of the genes including copy number variation and methylation. We further constructed a prognostic gene model using these CRGs and built the risk score formula. Univariate and multivariate Cox regression was applied to validate the risk score as an independent prognostic factor. The prognostic model was validated using 63 UVM samples from the GSE22138 cohort, an independent validation data set. Based on the risk scores for 80 patients with UVM from TCGA, we categorized the patients into high- and low-risk groups. Differentially expressed genes (DEGs) between groups were enriched in allograft rejection, hypoxia, glycolysis, TNFα signaling via NF-κB, and interferon-γ responses via Gene set enrichment analysis (GSEA). CD8 T cells and exhausted T cells were notably enriched in the high-risk group. In conclusion, the alteration of CRGs is related to patients with UVM, and the constructed CRG-related model may be helpful to predict the prognosis of such patients.

Antiviral effects of coinage metal-based nanomaterials to combat COVID-19 and its variants

The world has been suffering from the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic, and millions of people have been infected through human-to-human transmission and lost their lives within months. Although multidisciplinary scientific approaches have been employed to fight against this deadly pandemic, various mutations and diverse environments keep producing constraints in treating SARS-CoV-2. Indeed, the efficacy of the developed vaccines has been limited, and inoculation with the vaccines does not guarantee complete protection even though multiple doses are required, which is a frustrating process. Historically, coinage metals (Cu, Ag, and Au) have been well-known for their effectiveness in antiviral action as well as good biocompatibility, binding receptor inhibition, reactive oxygen species, and phototherapy properties. Thus, this review highlights the diagnostic and therapeutic mechanisms of SARS-CoV-2 using the antivirus ability and mode of action of coinage metals such as viral entry mechanisms into host cells and the NP-inhibition process, which are explained in detail. This article also draws attention to coinage metal nanomaterial-based approaches to treat other contagious viruses. In addition, coinage metal-based biosensors and an overview of some other biocompatible metal-based nanomaterials to fight against SARS-CoV-2 variants are discussed. Finally, the advantages, perspectives and challenges of coinage metal nanoparticles are given to fight against viral infections in the future.

The Role of Zinc and Copper in Platelet Activation and Pathophysiological Thrombus Formation in Patients with Pulmonary Embolism in the Course of SARS-CoV-2 Infection

To date, many studies have proved that COVID-19 increases the incidence of thrombus formation and coagulopathies but the exact mechanism behind such a disease outcome is not well known. In this review we collect the information and discuss the pathophysiology of thrombus formation in patients with pulmonary embolism in the course of COVID-19 disease and the role of zinc and copper in the process. Supplementation of zinc and copper may be beneficial for COVID-19 patients due to its anti-inflammatory and anti-oxidative properties. On the other hand, excess of those microelements in the organism may be harmful, that is why marking the level of those micronutrients should be done at first. We also propose further investigation of diagnostic and therapeutic options of zinc and copper in course of COVID-19 thrombus formation to their potential in patient care, with particular emphasis on the dosage and the duration of their misbalance.

Minerals and Cancer: Overview of the Possible Diagnostic Value

Simple Summary

Minerals are important but often overlooked compounds that are required for a variety of cellular biochemical processes and pathways that regulate cell proliferation. Their dietary imbalance, which is becoming more common in the diets of industrialized countries, is linked to an increased risk of cancer. The current review will present some of the most important minerals for human physiology and evaluate their potential application as cancer biomarkers.

Abstract

Cancer is the second leading cause of death worldwide and is expected to increase by one-third over the next two decades, in parallel with the growing proportion of the elderly population. Treatment and control of cancer incidence is a global issue. Since there is no clear way to prevent or cure this deadly malignancy, diagnostic, predictive, and prognostic markers for oncological diseases are of great therapeutic value. Minerals and trace elements are important micronutrients for normal physiological function of the body. They are abundant in natural food sources and are regularly included in dietary supplements whereas highly processed industrial food often contains reduced or altered amounts of them. In modern society, the daily intake, storage pools, and homeostasis of these micronutrients are dependent on certain dietary habits and can be thrown out of balance by malignancies. The current work summarizes the data on minerals and trace elements associated with abnormal accumulation or depletion states in tumor patients and discusses their value as potential tumor-associated biomarkers that could be introduced into cancer therapy.

Induction of autophagy via the ROS-dependent AMPK-mTOR pathway protects copper-induced spermatogenesis disorder

Copper (Cu) is a necessary micronutrient at lower concentration, while excessive Cu exposure or Cu homeostasis disorders can lead to toxicity. The mechanism of male reproductive toxicity induced by Cu is still unknown. This study aims to investigate whether autophagy plays an important role in copper-induced spermatogenesis disorder in vivo and vitro. The present study showed that copper sulfate (CuSO₄) might significantly promote autophagy level in the testis and mouse-derived spermatogonia cell line GC-1 spg cells. Concurrently, CuSO₄ could induce autophagy via AMPK-mTOR pathway that downregulated p-mTOR/mTOR and subsequently upregulated p-AMPKα/AMPKα as well as p-ULK1/ULK1. In the meanwhile, CuSO₄ treatment could also increase expression levels of the autophagy-related proteins. Then, the role of oxidative stress in CuSO₄-induced autophagy was investigated. The findings demonstrated that oxidative stress inhibitor (NAC) attenuated CuSO₄-induced autophagy in vivo and vitro, reversing the activation for AMPK-mTOR pathway. Additionally, the study also investigated how autophagy worked under the spermatogenesis disorder induced by CuSO₄. Inhibition of autophagy could decrease cell viability, and enhance the ROS accumulation and apoptosis in the GC-1 cells, meanwhile, the spermatogenesis disorder, oxidative stress and histopathological changes were increased in the testis. Furthermore, co-treatment with the apoptosis inhibitor (Z-VAD-FMK) could decrease the spermatogenesis disorder but not influence autophagy. Besides, the crosslink between autophagy and ferroptosis were also measured, the data showed that inhibition of autophagy could suppress CuSO₄-induced ferroptosis in in vivo and vitro. Altogether, abovementioned results indicated that CuSO₄ induced autophagy via oxidative stress-dependent AMPK-mTOR pathway in the GC-1 cells and testis, and autophagy activation possibly led to the generation of protection mechanism through oxidative damage and apoptosis inhibition, however, autophagy also aggravate CuSO₄ toxicology through promoting ferroptosis. Overall, autophagy plays a positive role for attenuating CuSO₄-induced testicular damage and spermatogenesis disorder. Our study provides a possible targeted therapy for Cu overload-induced reproduction toxicology.

Ionophore Ability of Carnosine and Its Trehalose Conjugate Assists Copper Signal in Triggering Brain-Derived Neurotrophic Factor and Vascular Endothelial Growth Factor Activation In Vitro

l-carnosine (β-alanyl-l-histidine) (Car hereafter) is a natural dipeptide widely distributed in mammalian tissues and reaching high concentrations (0.7-2.0 mM) in the brain. The molecular features of the dipeptide underlie the antioxidant, anti-aggregating and metal chelating ability showed in a large number of physiological effects, while the biological mechanisms involved in the protective role found against several diseases cannot be explained on the basis of the above-mentioned properties alone, requiring further research efforts. It has been reported that l-carnosine increases the secretion and expression of various neurotrophic factors and affects copper homeostasis in nervous cells inducing Cu cellular uptake in keeping with the key metal-sensing system. Having in mind this l-carnosine ability, here we report the copper-binding and ionophore ability of l-carnosine to activate tyrosine kinase cascade pathways in PC12 cells and stimulate the expression of BDNF. Furthermore, the study was extended to verify the ability of the dipeptide to favor copper signaling inducing the expression of VEGF. Being aware that the potential protective action of l-carnosine is drastically hampered by its hydrolysis, we also report on the behavior of a conjugate of l-carnosine with trehalose that blocks the carnosinase degradative activity. Overall, our findings describe a copper tuning effect on the ability of l-carnosine and, particularly its conjugate, to activate tyrosine kinase cascade pathways.

Copper impair autophagy on zebrafish (Danio rerio) gill epithelium

Copper (Cu) is an essential element for organism's metabolism, being controversially listed as a priority pollutant. Importantly, the toxicity of Cu has been linked to several cell death pathways. Thus, this study aimed to assess if macroautophagic pathways are triggered by Cu in zebrafish gill, the main target of waterborne pollutants. The electron microscopy findings indicated that Cu induced profound impacts on zebrafish gill structure and functions, being this tissue a biomarker sensitive enough to indicate early toxic effects. The findings also support a clear impairment of autophagy, througth the absence of phagossomes and the significant down-regulation mRNA transcript levels of microtubule-associated protein light chain 3 (LC3). The reduction of LC3 levels was often associated to an increase of apoptotic activation, indicating that the inhibition of macroautophagy triggers apoptosis in zebrafish gills. This study highlighted that the autophagic down-regulation might be affected through the activation of other cell death signaling pathway.

Potential molecular mechanisms of zinc- and copper-mediated antiviral activity on COVID-19

Novel coronavirus disease 2019 (COVID-19) has spread across the globe; and surprisingly, no potentially protective or therapeutic antiviral molecules are available to treat severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection. However, zinc (Zn) and copper (Cu) have been shown to exert protective effects due to their antioxidant, anti-inflammatory, and antiviral properties. Therefore, it is hypothesized that supplementation with Zn and Cu alone or as an adjuvant may be beneficial with promising efficacy and a favorable safety profile to mitigate symptoms, as well as halt progression of the severe form of SARS-CoV-2 infection. The objective of this review is to discuss the proposed underlying molecular mechanisms and their implications for combating SARS-CoV-2 infection in response to Zn and Cu administration. Several clinical trials have also included the use of Zn as an adjuvant therapy with dietary regimens/antiviral drugs against COVID-19 infection. Overall, this review summarizes that nutritional intervention with Zn and Cu may offer an alternative treatment strategy by eliciting their virucidal effects through several fundamental molecular cascades, such as, modulation of immune responses, redox signaling, autophagy, and obstruction of viral entry and genome replication during SARS-CoV-2 infection.

mtROS-mediated Akt/AMPK/mTOR pathway was involved in Copper-induced autophagy and it attenuates Copper-induced apoptosis in RAW264.7 mouse monocytes

Copper (Cu) is a trace element necessary in animals as well as human beings. However, excessive Cu is toxic to immunocytes, but the precise mechanism is largely unclear so far. This work was conducted aiming to examine the Cu-mediated autophagy mechanism together with its role in Cu toxicology in RAW264.7 cells. Here, we demonstrated that CuSO4 reduced the cell viability depending on its dose. CuSO4 could obviously increase autophagy in RAW264.7 cells. According to the obtained results, CuSO4 induced autophagy through Akt/AMPK/mTOR pathway which characterized by down regulation of p-Akt (Ser473)/Akt, p-mTOR/mTOR, p-ULK1(Ser757)/ULK1 and subsequent up-regulation of p-AMPKα/AMPKα and p-ULK1(Ser555)/ULK1. Furthermore, CuSO4 significantly induced the production of mitochondrial reactive oxygen species (mtROS). In addition, CuSO4-mediated apoptosis and autophagy might be suppressed through suppressing mtROS generation by exposure to Mito-TEMPO. Intriguingly, autophagy promotion with rapamycin could decrease the apoptosis and the inhibition of autophagy with knock down Atg5 could enhance the apoptosis induced by CuSO4. Moreover, our results suggested that mtROS is the original cause in CuSO4-induced apoptosis and autophagy. Additionally, CuSO4 induced autophagy through mtROS-dependent Akt/AMPK/mTOR signalling pathwayin RAW264.7 cells. Moreover, autophagy activation might potentially generate a protection mechanism for improving CuSO4-induced RAW264.7 cell apoptosis.

Rutin ameliorates copper sulfate-induced brain damage via antioxidative and anti-inflammatory activities in rats

Excessive exposure to Copper (Cu) may result in Cu toxicity and adversely affect health outcomes. We investigated the protective role of rutin on Cu-induced brain damage. Experimental rats were treated as follows: group I: control; group II: Cu-sulfate: 200 mg/kg; group III: Cu-sulfate, and rutin 100 mg/kg; and group IV: rutin 100 mg/kg, for 7 weeks. Cu only treatment significantly decreased body weight gain, while rutin cotreatment reversed this decrease. Cu treatment increased malondialdehyde, nitric oxide level, and myeloperoxidase activity and decreased superoxide dismutase and catalase activities in rat brain. Immunohistochemistry showed that COX-2, iNOS, and Bcl-2 proteins were strongly expressed, while Bax was mildly expressed in the brain of Cu-treated rats. Furthermore, brain histology revealed degenerated neurons, and perforated laminae of cerebral cortex in the Cu-only treated rats. Interestingly, coadministration of Cu and rutin reduced the observed histological alteration, improved inflammatory and antioxidant biomarkers, thereby protecting against Cu-induced brain damage via antioxidative and anti-inflammatory mechanisms.

COVID-19: The Potential Role of Copper and N-acetylcysteine (NAC) in a Combination of Candidate Antiviral Treatments Against SARS-CoV-2

BACKGROUND

On March 11, 2020, the World Health Organization (WHO) declared the outbreak of coronavirus disease (COVID-19) a pandemic. Since then, thousands of people have suffered and died, making the need for a treatment of severe acute respiratory syndrome-related coronavirus-2 (SARS-CoV-2) more crucial than ever.

MATERIALS AND METHODS

The authors carried out a search in PubMed, ClinicalTrials.gov and New England Journal of Medicine (NEJM) for COVID-19 to provide information on the most promising treatments against SARS-CoV-2.

RESULTS

Possible COVID-19 agents with promising efficacy and favorable safety profile were identified. The results support the combination of copper, N-acetylcysteine (NAC), colchicine and nitric oxide (NO) with candidate antiviral agents, remdesivir or EIDD-2801, as a treatment for patients positive for SARS-CoV-2.

CONCLUSION

The authors propose to study the effects of the combination of copper, NAC, colchicine, NO and currently used experimental antiviral agents, remdesivir or EIDD-2801, as a potential treatment scheme for SARS-COV-2.