Autophagic effects and mechanisms of silver nanoparticles in renal cells under low dose exposure

Review on the role of autophagy in the toxicity of nanoparticles and the signaling pathways involved

As the development of nanotechnology, the application of nanoproducts and the advancement of nanomedicine, the contact of nanoparticles (NPs) with human body is becoming increasingly prevalent. This escalation elevates the risk of NPs exposure for workers, consumers, researchers, and both aquatic and terrestrial organisms throughout the production, usage, and disposal stages. Consequently, evaluating nanotoxicity remains critically important, though standardized assessment criteria are still lacking. The diverse and complex properties of NPs further complicate the understanding of their toxicological mechanisms. Autophagy, a fundamental cellular process, exhibits dual functions-both pro-survival and pro-death. This review offers an updated perspective on the dual roles of autophagy in nanotoxicity and examines the factors influencing autophagic responses. However, no definitive framework exists for predicting NPs-induced autophagy. Beyond the conventional autophagy pathways, the review highlights specific transcription factors activated by NPs and explores metabolic reprogramming. Particular attention is given to NPs-induced selective autophagy, including mitophagy, ER-phagy, ferritinophagy, lysophagy, and lipophagy. Additionally, the review investigates autophagy's involvement in NPs-mediated biological processes such as ferroptosis, inflammation, macrophage polarization, epithelial-mesenchymal transition, tumor cell proliferation and drug resistance, as well as liver and kidney injury, neurotoxicity, and other diseases. In summary, this review presents a novel update on selective autophagy-mediated nanotoxicity and elucidates the broader interactions of autophagy in NPs-induced biological processes. Collectively, these insights offer valuable strategies for mitigating nanotoxicity through autophagy modulation and advancing the development of NPs in biomedical applications.

Bioinspired and Green Synthesis of Silver Nanoparticles for Medical Applications: A Green Perspective

Silver nanoparticles (AgNPs) possess unmatched chemical, biological, and physical properties that make them unique compounds as antimicrobial, antifungal, antiviral, and anticancer agents. With the increasing drug resistance, AgNPs serve as promising entities for targeted drug therapy against several bacterial, fungal, and viral components. In addition, AgNPs also serve as successful anticancer agents against several cancers, including breast, prostate, and lung cancers. Several works in recent years have been done towards the development of AgNPs by using plant extracts like flowers, leaves, bark, root, stem, and whole plant parts. The green method of AgNP synthesis thus has several advantages over chemical and physical methods, especially the low cost of synthesis, no toxic byproducts, eco-friendly production pathways, can be easily regenerated, and the bio-reducing potential of plant derived nanoparticles. Furthermore, AgNPs are biocompatible and do not harm normally functioning human or host cells. This review provides an exhaustive overview and potential of green synthesized AgNPs that can be used as antimicrobial, antifungal, antiviral, and anticancer agents. After a brief introduction, we discussed the recent studies on the development of AgNPs from different plant extracts, including leaf parts, seeds, flowers, stems, bark, root, and whole plants. In the following section, we highlighted the different therapeutic actions of AgNPs against various bacteria, fungi, viruses, and cancers, including breast, prostate, and lung cancers. We then highlighted the general mechanism of action of AgNPs. The advantages of the green synthesis method over chemical and physical methods were then discussed in the article. Finally, we concluded the review by providing future perspectives on this promising field in nanotechnology.

Silver Nanoparticles (AgNPs) as Enhancers of Everolimus and Radiotherapy Sensitivity on Clear Cell Renal Cell Carcinoma

Nanomedicine's advent has promised to revolutionize different biomedical fields, including oncology. Silver Nanoparticles (AgNPs) showed promising results in different tumor models. Clear cell Renal Cell Carcinoma (ccRCC) is especially challenging due to its late diagnosis, poor prognosis and treatment resistance. Therefore, defining new therapeutic targets and regimens could improve patient management. This study intends to evaluate AgNPs' effect in ccRCC cells and explore their potential combinatory effect with Everolimus and Radiotherapy. AgNPs were synthesized, and their effect was evaluated regarding their entering pathway, cellular proliferation capacity, ROS production, mitochondrial membrane depolarization, cell cycle analysis and apoptosis assessment. AgNPs were combined with Everolimus or used to sensitize cells to radiotherapy. AgNPs are cytotoxic to 786-O cells, a ccRCC cell line, entering through endocytosis, increasing ROS, depolarizing mitochondrial membrane, and blocking the cell cycle, leading to a reduction of proliferation capacity and apoptosis. Combined with Everolimus, AgNPs reduce cell viability and inhibit proliferation capacity. Moreover, 786-O is intrinsically resistant to radiation, but after AgNPs' administration, radiation induces cytotoxicity through mitochondrial membrane depolarization and S phase blockage. These results demonstrate AgNPs' cytotoxic potential against ccRCC and seem promising regarding the combination with Everolimus and sensitization to radiotherapy, which can, in the future, benefit ccRCC patients' management.

Dual Implications of Nanosilver-Induced Autophagy: Nanotoxicity and Anti-Cancer Effects

In recent years, efforts have been made to identify new anti-cancer therapies. Various types of nanomaterials, including silver nanoparticles (AgNPs), are being considered as an option. In addition to its well-known antibacterial activity, AgNPs exhibit cytotoxic potential in both physiological and cancer cells by inducing stress-mediated autophagy and apoptotic cell death. A rapidly growing collection of data suggests that the proper regulation of autophagic machinery may provide an efficient tool for suppressing the development of cancer. In this light, AgNPs have emerged as a potential anti-cancer agent to support therapy of the disease. This review summarizes current data indicating the dual role of AgNP-induced autophagy and highlights factors that may influence its protective vs. its toxic potential. It also stresses that our understanding of the cellular and molecular mechanisms of autophagy machinery in cancer cells, as well as AgNP-triggered autophagy in both normal and diseased cells, remains insufficient.

Long-term application of silver nanoparticles in dental restoration materials: potential toxic injury to the CNS

Silver nanoparticles (AgNPs) have durable and remarkable antimicrobial effects on pathogenic microorganisms, such as bacteria and fungi, in dental plaques. As such, they are widely added to dental restoration materials, including composite resins, denture bases, adhesives, and implants, to solve the problems of denture stomatitis, peri-implant inflammation, and oral infection caused by the long-term use of these dental restoration materials. However, AgNPs can be absorbed into the blood circulatory system through the nasal/oral mucosa, lungs, gastrointestinal tract, skin, and other pathways and then distributed into the lungs, kidneys, liver, spleen, and testes, thereby causing toxic injury to these tissues and organs. It can even be transported across the blood-brain barrier (BBB) and continuously accumulate in brain tissues, causing injury and dysfunction of neurons and glial cells; consequently, neurotoxicity occurs. Other nanomaterials with antibacterial or remineralization properties are added to dental restoration materials with AgNPs. However, studies have yet to reveal the neurotoxicity caused by dental restoration materials containing AgNPs. In this review, we summarize the application of AgNPs in dental restoration materials, the mechanism of AgNPs in cytotoxicity and toxic injury to the BBB, and the related research on the accumulation of AgNPs to cause changes of neurotoxicity. We also discuss the mechanisms of neurotoxicity caused by AgNPs and the mode and rate of AgNPs released from dental restorative materials added with AgNPs to evaluate the probability of neurotoxic injury to the central nervous system (CNS), and then provide a theoretical basis for developing new composite dental restoration materials. Mechanism of neurotoxicity caused by AgNPs: AgNPs in the blood circulation enter the brain tissue after being transported across the BBB through transendothelial cell pathway and paracellular transport pathway, and continuously accumulate in brain tissue, causing damage and dysfunction of neurons and glial cells which ultimately leads to neurotoxicity. The uptake of AgNPs by neurons, astrocytes and microglia causes damage to these cells. AgNPs with non-neurotoxic level often increases the secretion of a variety of cytokines, up-regulates the expression of metallothionein in glial cells, even up-regulates autophagy and inflammation response to protect neurons from the toxic damage of AgNPs. However, the protective effect of glial cells induced by AgNPs exposure to neurotoxic levels is insufficient, which leads to neuronal damage and dysfunction and even neuronal programmed cell death, eventually cause neurotoxicity.

Autophagy regulation by inorganic, organic, and organic/inorganic hybrid nanoparticles: Organelle damage, regulation factors, and potential pathways

The rapid development of nanotechnology requires a more thorough understanding of the potential health effects caused by nanoparticles (NPs). As a programmed cell death, autophagy is one of the biological effects induced by NPs, which maintain intracellular homeostasis by degrading damaged organelles and removing aggregates of defective proteins through lysosomes. Currently, autophagy has been shown to be associated with the development of several diseases. A significant number of research have demonstrated that most NPs can regulate autophagy, and their regulation of autophagy is divided into induction and blockade. Studying the autophagy regulation by NPs will facilitate a more comprehensive understanding of the toxicity of NPs. In this review, we will illustrate the effects of different types of NPs on autophagy, including inorganic NPs, organic NPs, and organic/inorganic hybrid NPs. The potential mechanisms by which NPs regulate autophagy are highlighted, including organelle damage, oxidative stress, inducible factors, and multiple signaling pathways. In addition, we list the factors influencing NPs-regulated autophagy. This review may provide basic information for the safety assessment of NPs.

Implications of ferroptosis in silver nanoparticle-induced cytotoxicity of macrophages

Metal nanoparticles (NPs) are widely used in daily life and commercial activities owing to their unique physicochemical properties. Consequently, there is an increasing risk of daily and occupational exposure to metal NPs, which raises concerns regarding their health hazards. Programmed cell deaths (PCDs) have been clarified to be involved in metal NP-induced cytotoxicity, including apoptosis, autophagy, and pyroptosis. However, whether and how ferroptosis, a newly recognized PCD, contributes to metal NP-induced cell death remain unclear. In this study, we investigated the ferroptotic effects of two representative metal NPs, silver nanoparticles (AgNPs) and gold nanoparticles (AuNPs), on macrophages in vitro. Our results revealed that AgNPs, rather than AuNPs, induced non-apoptotic PCD, accompanied by lipid peroxidation and iron homeostasis disorders, which are two hallmarks of ferroptosis, in macrophages. Treatment with a ferroptosis inhibitor (ferrostatin-1) and iron chelator (deferoxamine) reversed AgNP-induced PCD, corroborating the induction of ferroptosis upon exposure to AgNPs. Moreover, our results revealed that smaller AgNPs elicited greater ferroptotic effects on macrophages than larger ones. Importantly, ferroptosis in AgNP-treated macrophages was mainly triggered by AgNPs per se rather than by Ag ions. Overall, our study highlights the ferroptotic effects elicited by AgNPs in macrophages, which will promote the understanding of their cytotoxic effects and facilitate the safer design of metal nanoproducts.

Early Epigenetic Responses in the Genomic DNA Methylation Fingerprints in Cells in Response to Sublethal Exposure of Silver Nanoparticles

With the rapid development of nanotechnology and nanoscience, nanosafety assessment has raised public concern. Although many studies have illustrated that nanomaterials could lead to genotoxicity, the early alterations of DNA methylation with nanomaterials under low-dose exposure have not been completely clear. In this study, we investigated the potential effect and molecular mechanism of AgNPs on the alternation of DNA methylation fingerprints in HEK293T cells under sublethal exposure. Intriguingly, silver nanoparticle treatment increased 5-mC level and changed methylation-related enzyme contents. Mechanistically, we scrutinized the changes in the molecular signaling and biological functions by means of MeDIP-Seq and RNA-seq. Our results revealed that AgNPs might undermine a number of vital regulatory networks including the metabolic processes, biological regulation and other cellular processes. More specifically at the DNA methylation fingerprints, there were 12 up-regulated and simultaneous hypomethylated genes, and 22 down-regulated and concomitant hypermethylated genes in HEK293T cells responding to AgNPs. Notably, these genes were primarily involved in lipid metabolism and ion metabolism. Together, these responsive genes might be used as early sensitive indicators for the variations of early epigenetic integrity through changing the DNA methylation fingerprints, as reflective of biological risk and toxicity of silver nanoparticles under realistic exposure scenarios.

Cytotoxicity of Metal-Based Nanoparticles: From Mechanisms and Methods of Evaluation to Pathological Manifestations

Metal-based nanoparticles (NPs) are particularly important tools in tissue engineering-, drug carrier-, interventional therapy-, and biobased technologies. However, their complex and varied migration and transformation pathways, as well as their continuous accumulation in closed biological systems, cause various unpredictable toxic effects that threaten human and ecosystem health. Considerable experimental and theoretical efforts have been made toward understanding these cytotoxic effects, though more research on metal-based NPs integrated with clinical medicine is required. This review summarizes the mechanisms and evaluation methods of cytotoxicity and provides an in-depth analysis of the typical effects generated in the nervous, immune, reproductive, and genetic systems. In addition, the challenges and opportunities are discussed to enhance future investigations on safer metal-based NPs for practical commercial adoption.

Cancer Therapy by Silver Nanoparticles: Fiction or Reality?

As an emerging new class, metal nanoparticles and especially silver nanoparticles hold great potential in the field of cancer biology. Due to cancer-specific targeting, the consequently attenuated side-effects and the massive anti-cancer features render nanoparticle therapeutics desirable platforms for clinically relevant drug development. In this review, we highlight those characteristics of silver nanoparticle-based therapeutic concepts that are unique, exploitable, and achievable, as well as those that represent the critical hurdle in their advancement to clinical utilization. The collection of findings presented here will describe the features that distinguish silver nanoparticles from other anti-cancer agents and display the realistic opportunities and implications in oncotherapeutic innovations to find out whether cancer therapy by silver nanoparticles is fiction or reality.

Subacute silica nanoparticle exposure induced oxidative stress and inflammation in rat hippocampus combined with disruption of cholinergic system and behavioral functions

Increasing environmental exposure to silica nanoparticles (SiNPs) and limited neurotoxicity studies pose a challenge for safety evaluation and management of these materials. This study aimed to explore the adverse effects and underlying mechanisms of subacute exposure to SiNPs by the intraperitoneal route on hippocampus function in rats. Data showed that SiNPs induced a significant increase in oxidative/nitrosative stress markers including reactive oxygen species (ROS), malondialdehyde (MDA), protein oxidation (PCO) and nitrite (NO) production accompanied by reduced antioxidant enzyme activity (catalase, superoxide dismutase, and glutathione peroxidase) and decreased glutathione (GSH). Phenotypically, SiNPs exhibited spatial learning and memory impairment in the Morris water maze (MWM) test, a decrease of the discrimination index in the novel object recognition test (NORT) and higher anxiety-like behavior. SiNPs affected the cholinergic system as reflected by reduced acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) activity. In addition, SiNPs significantly increased mRNA expression level of genes related to inflammation (TNF-α, IL-1β, IL-6, and COX-2) and decreased mRNA expression level of genes related to cholinergic system including choline acetyltransferase (ChAT), vesicular acetylcholine transporter (VAChT), AChE, muscarinic acetylcholine receptor M1 (m1AChR) and nicotinic acetylcholine receptors (nAChR). Histopathological results further showed an alteration in the hippocampus of treated animals associated with marked vacuolation in different hippocampus areas. These findings provide new insights into the molecular mechanism of SiNPs-induced hippocampal alterations leading to impairment of cognitive and behavioral functions, and implicating oxidative stress and inflammation in the hippocampus, as well as disruption of cholinergic system.

Silver Nanoparticles Induced Oxidative Stress and Mitochondrial Injuries Mediated Autophagy in HC11 Cells Through Akt/AMPK/mTOR Pathway

Silver nanoparticles (AgNPs) are widely used in industrial products, and they have good antibacterial properties, with potential for prevention and treatment of cow mastitis. However, concerns exist about the cytotoxicity of AgNPs. Thus, we have studied the role of autophagy in AgNP-induced cytotoxicity in mouse HC11 mammary epithelium cells. We found that AgNPs injured HC11 cells, with release of lactate dehydrogenase (LDH). AgNPs also induced autophagy in HC11 cells, which was associated with oxidative stress, as indicated by increased reactive oxygen species (ROS) and increased expression of hemoxygenase-1(HO-1) and Nrf2. Mitochondria were altered by AgNPs: mitochondrial membrane potential (MMP) was decreased and the expression of PINK1 and Parkin was increased. AgNPs also increased the expression of p-AMPK and decreased the expression of p-Akt and p-mTOR. The addition of 3-methyl adenine inhibited autophagy and enhanced the cytotoxicity of AgNPs, indicating that autophagy is protective against AgNP-induced cell death. In summary, AgNPs induced protective autophagy in HC11 cells via the Akt/AMPK/mTOR pathway, associated with cellular oxidative stress and mitochondrial alterations. Our research confirms that AgNPs may damage the breast tissue in clinical applications and should be used with caution. Further research is necessary to clarify whether the damage caused by AgNPs will affect the lactation function of the mammary glands and possible residues in milk.

Biosynthesis of silver nanoparticles using Sambucus nigra L. fruit extract for targeting cell death in oral dysplastic cells

The study aims to evaluate the impact of silver nanoparticles, phytosynthesized with polyphenols from Sambucus nigra L. (SN) fruit extract (AgSN), on dysplastic oral keratinocytes (DOK) and human gingival fibroblasts (HGF) in terms of cell viability and apoptosis. The morphology and ultrastructure of treated cells as well as the mechanisms involved in cell death induction were investigated in DOK cultures. The structure of AgSN was studied by using the appropriate analysis tools such as UV-Vis, transmission electron microscopy, Raman spectroscopy, dynamic light scattering (DLS) and zeta potential assessment. DOK and HGF were treated either with silver nanoparticles capped with Sambucus nigra L. extract or with SN extract. Untreated cells were used as controls. Viability was determined by MTS assay. Transmission electronic microscopy (TEM) was used to evaluate the intracellular localization of the nanoparticles at 4 and 24 h. Annexin V-FITC/propidium iodide staining and the expressions of p53, BAX, BCL2, NFkB, phosphorylated NFkB (pNFkB), pan AKT, pan phosphoAKT, LC3B and ɣH₂AX were evaluated to quantify the cell death. ELISA measurements of TNF-α and TRAIL was used for the study of the inflammatory response. Oxidative stress damage induced by nanoparticles was assessed by the malondialdehyde (MDA) level. Silver nanoparticles stimulated HGF proliferation and significantly diminished DOK viability at doses higher than 20 μg/ml. TEM analysis demonstrated the internalization of silver nanoparticles and showed ultrastructural changes of cells such as the appearance of vacuoles, autophagosomes, endosomes. AgSN inhibited the pro-survival molecules and regulators of apoptosis, diminished oxidative stress and inflammation and induced cell death through various mechanisms: necrosis, autophagy and DNA lesions. SN extract had antioxidant and anti-inflammatory effect and increased the DNA lesions and autophagy in DOK cells. Silver nanoparticles protected the normal cells and induced cell death in dysplastic cells by different mechanisms thus offering beneficial effects in the treatment of oral dysplasia.

Silver nanoparticles induced cytotoxicity in HT22 cells through autophagy and apoptosis via PI3K/AKT/mTOR signaling pathway

With the widespread application and inevitable environmental exposure, silver nanoparticles (AgNPs) can be accumulated in various organs. More serious concerns are raised on the biological safety and potential toxicity of AgNPs in the central nervous system (CNS), especially in the hippocampus. This study aimed to investigate the biological effects and the role of PI3K/AKT/mTOR signaling pathway in AgNPs mediated cytotoxicity using the mouse hippocampal neuronal cell line (HT22 cells). AgNPs reduced cell viability and induced membrane leakage in a dose-dependent manner, determined by the MTT and LDH assay. In doses of 25, 50, 100 μg mL^-1 for 24 h, AgNPs promoted the excessive production of reactive oxygen species (ROS) and caused the oxidative stress in HT22 cells. AgNPs induced autophagy, determined by the transmission electron microscopy observation, upregulation of LC3 II/I and downregulation of p62 expression levels. The mechanistic investigation showed that the PI3K/AKT/mTOR signaling pathway was activated by phosphorylation, which was enrolled in an AgNP-induced autophagy process. AgNPs could further trigger the apoptosis by upregulation of caspase-3 and Bax and downregulation of Bcl-2 in HT22 cells. These results revealed AgNP-induced cytotoxicity in HT22 cells, which was mediated by autophagy and apoptosis via the PI3K/AKT/mTOR signaling pathway. The study could provide the experimental evidence and explanation for the potential neurotoxicity triggered by AgNPs in vitro.

Mitophagy-lysosomal pathway is involved in silver nanoparticle-induced apoptosis in A549 cells

With the increasing use of silver nanoparticles (AgNPs) in biological materials, the cytotoxicity caused by these particles has attracted much attention. However, the molecular mechanism underlying AgNP cytotoxicity remains unclear. In this study, we aimed to systematically investigate the toxicity induced by AgNP exposure to the lung adenocarcinoma A549 cell line at the subcellular and signaling pathway levels and elucidate the related molecular mechanism. The survival rate of cells exposed to AgNPs at 0, 20, 40, 80, and 160 μg/mL for 24 or 48 h decreased in a dose- and time-dependent manner. AgNPs induced autophagy and mitophagy, determined by the transmission electron microscopy investigation and upregulation of LC3 II/I, p62, PINK1, and Parkin expression levels. AgNP treatment induced lysosomal injury, including the decline of lysosomal membrane integrity and increase in cathepsin B level. The decreased in mitochondrial membrane potential, along with upregulation of cytochrome c, caspases 9 and 3, and BAX/BCL2, further suggested that mitochondrial injury were involved in AgNP-induced apoptosis. In addition, mitochondrial injury may further lead to excessive production of reactive oxygen species and oxidative/ antioxidant imbalance. The results suggested that AgNPs could regulate autophagy via mitochondrial and lysosome injury in A549 cells. The information of the molecular mechanism will provide an experimental basis for the safe application of nanomaterials.

Vitexin suppresses renal cell carcinoma by regulating mTOR pathways

Background

Renal cell carcinoma (RCC) is one of the most common malignant tumors in the world. Vitexin (apigenin-8-C-D-glucopyranoside), a bioactive compound isolated from a variety of plants, has multiple protective effects on human health. The purpose of this study was to investigate the role of vitexin in RC and the related molecular mechanism.

Methods

Proliferation was tested with Cell Counting Kit-8 and Edu staining. Apoptosis was studied with flow cytometry. Immunofluorescent was applied to show LC3 spots. BALB/c nude mice bearing ACHN cells were established and immunohistochemical staining was applied to validate the in vivo effects of vitexin. All the effects and possible signaling pathways involved were validated with western blotting.

Results

Seventy micromole of vitexin started to show significant effect on the growth of normal renal tubular epithelial cells (HK-2), so 0, 10, 20 and 40 µM of vitexin were used in later experiments. Vitexin inhibited growth and induced apoptosis of ACHN and OS-RC-2 cells in a dose-dependent manner, and promoted excessive autophagy by reducing p62 levels and increasing Beclin1 and LC3II levels. Western blotting revealed that vitexin significantly increased the phosphorylation levels of Adenosine Monophosphate Activated Protein Kinase (AMPK) and c-Jun N-terminal kinase (JNK) in ACHN and OS-RC-2 cells, while decreasing the phosphorylation levels of phosphatidylinositol 3-kinase/activates protein kinase/mammalian target of rapamycin (PI3K/AKT/mTOR). In BALB/c nude mice bearing ACHN cells, vitexin inhibited tumor growth, reduced Ki67 and increased caspase-3 levels in the tumor tissues.

Conclusions

The results indicated that the tumor suppressive role of vitexin in ACHN and OS-RC-2 cells involved AMPK/mTOR, PI3K/AKT/mTOR, and JNK pathways. Therefore, vitexin may be a promising drug for the treatment of RCC.

Nanoparticles induce autophagy via mTOR pathway inhibition and reactive oxygen species generation

Due to their unique physicochemical properties, nanoparticles (NPs) have been increasingly developed for use in various fields. However, there has been both growing negative concerns with toxicity and positive realization of opportunities in nanomedicine, coming from the growing understanding of the associations between NPs and the human body, particularly relating to their cellular autophagic effects. This review summarizes NP-induced autophagy via the modulation of the mTOR signaling pathway and other associated signals including AMPK and ERK and also demonstrates how reactive oxygen species generation greatly underlies the regulation processes. The perspectives in this review aim to contribute to NP design, particularly in consideration of nanotoxicity and the potential for the precise application of NPs in nanomedicine.

Nanoparticle-Mediated Therapeutic Application for Modulation of Lysosomal Ion Channels and Functions

Applications of nanoparticles in various fields have been addressed. Nanomaterials serve as carriers for transporting conventional drugs or proteins through lysosomes to various cellular targets. The basic function of lysosomes is to trigger degradation of proteins and lipids. Understanding of lysosomal functions is essential for enhancing the efficacy of nanoparticles-mediated therapy and reducing the malfunctions of cellular metabolism. The lysosomal function is modulated by the movement of ions through various ion channels. Thus, in this review, we have focused on the recruited ion channels for lysosomal function, to understand the lysosomal modulation through the nanoparticles and its applications. In the future, lysosomal channels-based targets will expand the therapeutic application of nanoparticles-associated drugs.

Silver nanoparticles regulate autophagy through lysosome injury and cell hypoxia in prostate cancer cells

With the rapid development of nanotechnology, nanomaterials are now being used for cancer treatment. Although studies on the application of silver nanoparticles in cancer treatment are burgeoning, few studies have investigated the toxicology mechanisms of autophagy in cancer cells under exposure to sublethal silver nanoparticles. Here, we clarified the distinct mechanisms of silver nanoparticles for the regulation of autophagy in prostate cancer PC-3 cells under sublethal exposure. Silver nanoparticle treatment caused lysosome injury, including the decline of lysosomal membrane integrity, decrease of lysosomal quantity, and attenuation of lysosomal protease activity, which resulted in blockage of autophagic flux. In addition, sublethal silver nanoparticle exposure activated AMP-activated protein kinase/mammalian target of rapamycin-dependent signaling pathway to modulate autophagy, which resulted from silver nanoparticles-induced cell hypoxia and energy deficiency. Taken together, the results show that silver nanoparticles could regulate autophagy via lysosome injury and cell hypoxia in PC-3 cells under sublethal dose exposure. This study will provide an experimental basis for the cancer therapy of nanomaterials.

Ameliorative effect of ursolic acid on ochratoxin A-induced renal cytotoxicity mediated by Lonp1/Aco2/Hsp75

Ochratoxin A (OTA) is a mycotoxin ubiquitous in feeds and foodstuffs. The water-insoluble pentacyclic triterpene bioactive compound, ursolic acid (UA), is widespread in various cuticular waxes of edible fruits, food materials, and medicinal plants. Although studies have reported that oxidative stress was involved in both the nephrotoxicity of OTA and the renoprotective function of UA, the role of stress-responsive Lon protease 1 (Lonp1) in the renoprotection of UA against OTA is still unknown. In this study, cell viability, reactive oxygen species (ROS) production, and several proteins' expressions of human embryonic kidney 293T (HEK293T) cells in response to UA, OTA, and/or Lonp1 inhibitor CDDO-me treatment were detected to reveal the protective mechanism of UA against OTA-induced renal cytotoxicity. Results indicated that a 2 h-treatment of 1 μM UA could significantly alleviate the ROS production and cell death induced by a 24 h-treatment of 8 μM OTA in HEK293T cells (P < 0.05). Compared with the control, the protein expressions of Lonp1, Aco2 and Hsp75 were significantly inhibited after 8 μM OTA treating for 24 h (P < 0.05), which could be notably reversed by the pre-treatment and post-treatment of 1 μM UA (P < 0.05). The protein expressions of Lonp1, Aco2 and Hsp75 were inhibited by the addition of CDDO-me. The three protein expression trends were similar before and after the addition of CDDO-me. In conclusion, OTA could inhibit the expression of Lonp1, suppressing Aco2 and Hsp75 as a result, thereby activating ROS and inducing cell death in HEK293T cells, which could be alleviated by UA pre-treatment.