Ultra-Small Iron Nanoparticles Target Mitochondria Inducing Autophagy, Acting on Mitochondrial DNA and Reducing Respiration

All Roads Lead to Rome: Comparing Nanoparticle- and Small Molecule-Driven Cell Autophagy

Autophagy, vital for removing cellular waste, is triggered differently by small molecules and nanoparticles. Small molecules, like rapamycin, non-selectively activate autophagy by inhibiting the mTOR pathway, which is essential for cell regulation. This can clear damaged components but may cause cytotoxicity with prolonged use. Nanoparticles, however, induce autophagy, often causing oxidative stress, through broader cellular interactions and can lead to a targeted form known as "xenophagy." Their impact varies with their properties but can be harnessed therapeutically. In this review, the autophagy induced by nanoparticles is explored and small molecules across four dimensions: the mechanisms behind autophagy induction, the outcomes of such induction, the toxicological effects on cellular autophagy, and the therapeutic potential of employing autophagy triggered by nanoparticles or small molecules. Although small molecules and nanoparticles each induce autophagy through different pathways and lead to diverse effects, both represent invaluable tools in cell biology, nanomedicine, and drug discovery, offering unique insights and therapeutic opportunities.

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.

Valorization of Olea europaea and olive oil processing by-products/wastes

Olive (Olea europaea) is a native species from the Mediterranean region and widely cultivated for its edible fruit, known as olives. Olives are a rich source of monounsaturated fatty acids, vitamin E, and polyphenols, and have been shown to have various health benefits. They are commonly used for cooking and are also employed in cosmetics and the pharmaceutical industry. The extract obtained from olive fruits and several subproducts of the olive industry has demonstrated several biological activities mainly associated with their antioxidant and inflammatory properties. Thus, olives, olive-derived products, and subproducts of the olive industry have gained popularity in recent years due to their potential health benefits and their use in traditional medicine. The present chapter summarizes the main applications of Olea europaea and olive oil processing by-products as therapeutic agents against cancer, cardiovascular diseases, and antimicrobial agents.

Programmed T cells infiltration into lung metastases with harnessing dendritic cells in cancer immunotherapies by catalytic antigen-capture sponges

T lymphocytes served as immune surveillance to suppress metastases by physically interacting with cancer cells. Whereas tumor immune privilege and heterogeneity protect immune attack, it limits immune cell infiltration into tumors, especially in invasive metastatic clusters. Here, a catalytic antigen-capture sponge (CAS) containing the catechol-functionalized copper-based metal organic framework (MOF) and chloroquine (CQ) for programming T cells infiltration is reported. The intravenously injected CAS accumulates at the tumor via the folic acid-mediated target and margination effect. In metastases, Fenton-like reaction induced by copper ions of CAS disrupts the intracellular redox potential, i.e., chemodynamic therapy (CDT), thereby reducing glutathione (GSH) levels. Furthermore, CQ helps inhibit autophagy by inducing lysosomal deacidification during CDT. This process leads to the breakdown of self-defense mechanisms, which exacerbates cytotoxicity. The therapies promote the liberation of tumor-associated antigens, such as neoantigens and damage-associated molecular patterns (DAMPs). Subsequently, the catechol groups present on CAS perform as antigen reservoirs and transport the autologous tumor-associated antigens to dendritic cells, resulting in prolonged immune activation. The CAS, which is capable of forming in-situ, serves as an antigen reservoir in CDT-mediated lung metastasis and leads to the accumulation of immune cells in metastatic clusters, thus hindering metastatic tumors.

Rational targeting of autophagy in colorectal cancer therapy: From molecular interactions to pharmacological compounds

The abnormal progression of tumors has been a problem for treatment of cancer and therapeutic should be directed towards targeting main mechanisms involved in tumorigenesis in tumors. The genomic mutations can result in changes in biological mechanisms in human cancers. Colorectal cancer is one of the most malignant tumors of gastrointestinal tract and its treatment has been faced some difficulties due to development of resistance in tumor cells and also, their malignant behavior. Hence, new therapeutic modalities for colorectal cancer are being investigated. Autophagy is a "self-digestion" mechanism that is responsible for homeostasis preserving in cells and its aberrant activation/inhibition can lead to tumorigenesis. The current review focuses on the role of autophagy mechanism in colorectal cancer. Autophagy may be associated with increase/decrease in progression of colorectal cancer due to mutual function of this molecular mechanism. Pro-survival autophagy inhibits apoptosis to increase proliferation and survival rate of colorectal tumor cells and it is also involved in cancer metastasis maybe due to EMT induction. In contrast, pro-death autophagy decreases growth and invasion of colorectal tumor cells. The status of autophagy (upregulation and down-regulation) is a determining factor for therapy response in colorectal tumor cells. Therefore, targeting autophagy can increase sensitivity of colorectal tumor cells to chemotherapy and radiotherapy. Interestingly, nanoparticles can be employed for targeting autophagy in cancer therapy and they can both induce/suppress autophagy in tumor cells. Furthermore, autophagy modulators can be embedded in nanostructures in improving tumor suppression and providing cancer immunotherapy.

Functionalized and Nonfunctionalized Nanosystems for Mitochondrial Drug Delivery with Metallic Nanoparticles

Background: The application of metallic nanoparticles as a novel therapeutic tool has significant potential to facilitate the treatment and diagnosis of mitochondria-based disorders. Recently, subcellular mitochondria have been trialed to cure pathologies that depend on their dysfunction. Nanoparticles made from metals and their oxides (including gold, iron, silver, platinum, zinc oxide, and titanium dioxide) have unique modi operandi that can competently rectify mitochondrial disorders. Materials: This review presents insight into the recent research reports on exposure to a myriad of metallic nanoparticles that can alter the dynamic ultrastructure of mitochondria (via altering metabolic homeostasis), as well as pause ATP production, and trigger oxidative stress. The facts and figures have been compiled from more than a hundred PubMed, Web of Science, and Scopus indexed articles that describe the essential functions of mitochondria for the management of human diseases. Result: Nanoengineered metals and their oxide nanoparticles are targeted at the mitochondrial architecture that partakes in the management of a myriad of health issues, including different cancers. These nanosystems not only act as antioxidants but are also fabricated for the delivery of chemotherapeutic agents. However, the biocompatibility, safety, and efficacy of using metal nanoparticles is contested among researchers, which will be discussed further in this review.

Influence of a concurrent exercise training program during pregnancy on the placenta mitochondrial DNA integrity and content of minerals with enzymatic relevance. The GESTAFIT project

INTRODUCTION

We aimed i) to investigate the effects of a concurrent (aerobic plus strength) exercise intervention during pregnancy on placental mtDNA copy number, proportion of deleted mtDNA, and on the content of some trace and ultra-trace minerals with coenzymatic relevance; ii) to explore the association of such mitochondrial markers with the concentration of these minerals.

METHODS

For the present study specific aims, 47 placentas were randomly selected from women that participated in the GESTAFIT project into exercise (n = 24) or control (n = 23) groups. The exercise group followed a concurrent aerobic and strength training program, three 60-min sessions/week, from the 17th gestational week until birth. Placenta tissue was collected and processed for minerals determination by the inductively coupled plasma mass spectrometry technique. RT-PCR was used to determine placentas mtDNA copy number and ND1/ND4 deletion.

RESULTS

After adjusting for potential confounders, the mothers who participated in the exercise program had placentas with greater mtDNA copy number (p = 0.04) and lower mtDNA deletion (p = 0.003). Placentas from mothers in the exercise group presented higher manganese content than those from the controls (0.26 ± 0.03 mg/dL vs. 0.13 ± 0.03 mg/dL, p = 0.003). Placenta manganese content was significantly associated with lower mtDNA deletions (r = -0.382) and greater mtDNA copy number (r = 0.513). Iron content was associated with higher mtDNA copy number (r = 0.393). Selenium content was associated with lower mtDNA deletion (r = -0.377) and greater mtDNA copy number (r = 0.442). Finally, zinc and magnesium content were associated with higher mtDNA copy number (r = 0.447 and r = 0.453, respectively).

DISCUSSION

This concurrent exercise training program induced a better placental status, which might be mediated through an improvement of mitochondrial bioenergetics and antioxidative capacity.

Elucidating the Therapeutic Potential of Bis(Maltolato)OxoVanadium(IV): The Protective Role of Copper in Cellular Metabolism

Vanadium (V) is a trace mineral whose biological activity, role as a micronutrient, and pharmacotherapeutic applications remain unknown. Over the last years, interest in V has increased due to its potential use as an antidiabetic agent mediated by its ability to improve glycemic metabolism. However, some toxicological aspects limit its potential therapeutic application. The present study aims to evaluate the effect of the co-treatment with copper (Cu) and bis(maltolato)oxovanadium(IV) (BMOV) as a possible strategy to reduce the toxicity of BMOV. Treating hepatic cells with BMOV reduced cell viability under the present conditions, but cell viability was corrected when cells were co-incubated with BMOV and Cu. Additionally, the effect of these two minerals on nuclear and mitochondrial DNA was evaluated. Co-treatment with both metals reduced the nuclear damage caused by BMOV. Moreover, treatment with these two metals simultaneously tended to reduce the ND1/ND4 deletion of the mitochondrial DNA produced with the treatment using BMOV alone. In conclusion, these results showed that combining Cu and V could effectively reduce the toxicity associated with V and enhance its potential therapeutic applications.

Mitophagy Induced by Metal Nanoparticles for Cancer Treatment

Research on nanoparticles, especially metal nanoparticles, in cancer therapy is gaining momentum. The versatility and biocompatibility of metal nanoparticles make them ideal for various applications in cancer therapy. They can bring about apoptotic cell death in cancer cells. In addition to apoptosis, nanoparticles mediate a special type of autophagy facilitated through mitochondria called mitophagy. Interestingly, nanoparticles with antioxidant properties are capable of inducing mitophagy by altering the levels of reactive oxygen species and by influencing signaling pathways like PINK/Parkin pathway and P13K/Akt/mTOR pathway. The current review presents various roles of metal nanoparticles in inducing mitophagy in cancer cells. We envision this review sheds some light on the blind spots in the research related to mitophagy induced by nanoparticles for cancer treatment.

Distinct Uptake Routes Participate in Silver Nanoparticle Engulfment by Earthworm and Human Immune Cells

The consequences of engineered silver nanoparticle (AgNP) exposure and cellular interaction with the immune system are poorly understood. The immunocytes of the Eisenia andrei earthworm are frequently applied in ecotoxicological studies and possess functional similarity to vertebrate macrophages. Hence, we characterized and compared the endocytosis mechanisms for the uptake of 75 nm AgNPs by earthworm coelomocytes, human THP-1 monocytes, and differentiated THP-1 (macrophage-like) cells. Our results indicate that microtubule-dependent, scavenger-receptor, and PI3K signaling-mediated macropinocytosis are utilized during AgNP engulfment by human THP-1 and differentiated THP-1 cells. However, earthworm coelomocytes employ actin-dependent phagocytosis during AgNPs uptake. In both human and earthworm immunocytes, AgNPs were located in the cytoplasm, within the endo-/lysosomes. We detected that the internalization of AgNPs is TLR/MyD88-dependent, also involving the bactericidal/permeability-increasing protein (BPI) in the case of human immunocytes. The exposure led to decreased mitochondrial respiration in human immunocytes; however, in coelomocytes, it enhanced respiratory parameters. Our findings provide more data about NP trafficking as nano-carriers in the nanomedicine field, as well as contribute to an understanding of the ecotoxicological consequences of nanoparticle exposure.

Mitochondria-Targeted, Nanoparticle-Based Drug-Delivery Systems: Therapeutics for Mitochondrial Disorders

Apart from ATP generation, mitochondria are involved in a wide range of functions, making them one of the most prominent organelles of the human cell. Mitochondrial dysfunction is involved in the pathophysiology of several diseases, such as cancer, neurodegenerative diseases, cardiovascular diseases, and metabolic disorders. This makes it a target for a variety of therapeutics for the diagnosis and treatment of these diseases. The use of nanoparticles to target mitochondria has significant importance in modern times because they provide promising ways to deliver drug payloads to the mitochondria by overcoming challenges, such as low solubility and poor bioavailability, and also resolve the issues of the poor biodistribution of drugs and pharmacokinetics with increased specificity. This review assesses nanoparticle-based drug-delivery systems, such as liposomes, DQAsome, MITO-Porters, micelles, polymeric and metal nanocarriers, as well as quantum dots, as mitochondria-targeted strategies and discusses them as a treatment for mitochondrial disorders.

Programmed Catalytic Therapy-Mediated ROS Generation and T-Cell Infiltration in Lung Metastasis by a Dual Metal-Organic Framework (MOF) Nanoagent

Nano-catalytic agents actuating Fenton-like reaction in cancer cells cause intratumoral generation of reactive oxygen species (ROS), allowing the potential for immune therapy of tumor metastasis via the recognition of tumor-associated antigens. However, the self-defense mechanism of cancer cells, known as autophagy, and unsustained ROS generation often restricts efficiency, lowering the immune attack, especially in invading metastatic clusters. Here, a functional core-shell metal-organic framework nanocube (dual MOF) doubling as a catalytic agent and T cell infiltration inducer that programs ROS and inhibits autophagy is reported. The dual MOF integrated a Prussian blue (PB)-coated iron (Fe²⁺)-containing metal-organic framework (MOF, MIL88) as a programmed peroxide mimic in the cancer cells, facilitating the sustained ROS generation. With the assistance of Chloroquine (CQ), the inhibition of autophagy through lysosomal deacidification breaks off the self-defense mechanism and further improves the cytotoxicity. The purpose of this material design was to inhibit autophagy and ROS efficacy of the tumor, and eventually improve T cell recruitment for immune therapy of lung metastasis. The margination and internalization-mediated cancer cell uptake improve the accumulation of dual MOF of metastatic tumors in vivo. The effective catalytic dual MOF integrated dysfunctional autophagy at the metastasis elicits the ~3-fold recruitment of T lymphocytes. Such synergy of T cell recruitment and ROS generation transported by dual MOF during the metastases successfully suppresses more than 90% of tumor foci in the lung.

Cellular Toxicity Mechanisms and the Role of Autophagy in Pt(IV) Prodrug-Loaded Ultrasmall Iron Oxide Nanoparticles Used for Enhanced Drug Delivery

Ultrasmall iron oxide nanoparticles (<10 nm) were loaded with cis-diamminetetrachloroplatinum (IV), a cisplatin (II) prodrug, and used as an efficient nanodelivery system in cell models. To gain further insight into their behavior in ovarian cancer cells, the level of cellular incorporation as well as the platination of mitochondrial and nuclear DNA were measured using inductively coupled plasma mass spectrometry (ICP-MS) strategies. Quantitative Pt results revealed that after 24 h exposure to 20 µM Pt in the form of the Pt(IV)-loaded nanoparticles, approximately 10% of the incorporated Pt was associated with nuclear DNA. This concentration increased up to 60% when cells were left to stand in drug-free media for 3 h. These results indicated that the intracellular reducing conditions permitted the slow release of cisplatin (II) from the cisplatin (IV)-loaded nanoparticles. Similar results were obtained for the platination of mitochondrial DNA, which reached levels up to 17,400 ± 75 ng Pt/ mg DNA when cells were left in drug-free media for 3 h, proving that this organelle was also a target for the action of the released cisplatin (II). The time-dependent formation of Pt-DNA adducts could be correlated with the time-dependent decrease in cell viability. Such a decrease in cell viability was correlated with the induction of apoptosis as the main route of cell death. The formation of autophagosomes, although observed upon exposure in treated cells, does not seem to have played an important role as a means for cells to overcome nanoparticles’ toxicity. Thus, the designed nanosystem demonstrated high cellular penetration and the “in situ” production of the intracellularly active cisplatin (II), which is able to induce cell death, in a sustained manner.