Toxicity of polyhydroxylated fullerene to mitochondria

Versatile applications of fullerenol nanoparticles

Nanomaterials have become increasingly important over time as research technology has enabled the progressively precise study of materials at the nanoscale. Developing an understanding of how nanomaterials are produced and tuned allows scientists to utilise their unique properties for a variety of applications, many of which are already incorporated into commercial products. Fullerenol nanoparticles C60(OH)n, 2 ≤ n ≤ 44 are fullerene derivatives and are produced synthetically. They have good biocompatibility, low toxicity and no immunological reactivity. In addition, their nanometre size, large surface area to volume ratio, ability to penetrate cell membranes, adaptable surface that can be easily modified with different functional groups, drug release, high physical stability in biological media, ability to remove free radicals, magnetic and optical properties make them desirable candidates for various applications. This review comprehensively summarises the various applications of fullerenol nanoparticles in different scientific fields such as nanobiomedicine, including antibacterial and antiviral agents, and provides an overview of their use in agriculture and biosensor technology. Recommendations are also made for future research that would further elucidate the mechanisms of fullerenols actions.

New insights into the impact of polystyrene micro/nanoplastics on the nutritional quality of marine jacopever (Sebastes schlegelii)

Microplastics (MPs) and nanoplastics (NPs) are ubiquitous in the marine environments due to the wide use and mismanagement of plastics. However, the effect of MPs/NPs on the nutrition quality of economic species is poorly understood, and their underlying mechanisms remained unclear. We therefore investigated the impacts of polystyrene MPs/NPs on the nutrition composition of marine jacopever Sebastes schlegelii from the perspective of assimilation and metabolism. Results showed that NPs reduced more nutrition quality than MPs. Despite no notable impact on intestinal microbiota function, MPs/NPs influenced the assimilation of fish through intestinal damage. Furthermore, NPs induced greater damage to hepatocyte metabolism than MPs, caused by hepatocyte uptake through membrane protein pumps/channels and clathrin/caveolin-mediated endocytosis for NPs, while through phagocytosis/pinocytosis for MPs. NPs triggered more cell apoptosis signals in Ferroptosis and FoxO signaling pathways than MPs, destroying mitochondria structure. Compared with MP treatments, a significant upregulation of genes (PRODH and SLC25A25A) associated with the electron transfer chain of mitochondria was detected in the NP treatments, influencing the tricarboxylic acid cycle and interfering with liver metabolism of proteins, fatty acid, glycerol phospholipids, and carbohydrates. This work provides new insights into the potential impacts of MPs/NPs on the quality and safety of seafood.

Tailoring the Inherent Properties of Biobased Nanoparticles for Nanomedicine

Biobased nanoparticles are at the leading edge of the rapidly developing field of nanomedicine and biotherapeutics. Their unique size, shape, and biophysical properties make them attractive tools for biomedical research, including vaccination, targeted drug delivery, and immune therapy. These nanoparticles are engineered to present native cell receptors and proteins on their surfaces, providing a biomimicking camouflage for therapeutic cargo to evade rapid degradation, immune rejection, inflammation, and clearance. Despite showing promising clinical relevance, commercial implementation of these biobased nanoparticles is yet to be fully realized. In this perspective, we discuss advanced biobased nanoparticle designs used in medical applications, such as cell membrane nanoparticles, exosomes, and synthetic lipid-derived nanoparticles, and highlight their benefits and potential challenges. Moreover, we critically assess the future of preparing such particles using artificial intelligence and machine learning. These advanced computational tools will be able to predict the functional composition and behavior of the proteins and cell receptors present on the nanoparticle surfaces. With more advancement in designing new biobased nanoparticles, this field of research could play a key role in dictating the future rational design of drug transporters, thereby ultimately improving overall therapeutic outcomes.

Glucose Biosensor Based on Glucose Oxidase Immobilized on BSA Cross-Linked Nanocomposite Modified Glassy Carbon Electrode

Glucose sensors based blood glucose detection are of great significance for the diagnosis and treatment of diabetes because diabetes has aroused wide concern in the world. In this study, bovine serum albumin (BSA) was used to cross-link glucose oxidase (GOD) on a glassy carbon electrode (GCE) modified by a composite of hydroxy fullerene (HFs) and multi-walled carbon nanotubes (MWCNTs) and protected with a glutaraldehyde (GLA)/Nafion (NF) composite membrane to prepare a novel glucose biosensor. The modified materials were analyzed by UV-visible spectroscopy (UV-vis), transmission electron microscopy (TEM), and cyclic voltammetry (CV). The prepared MWCNTs-HFs composite has excellent conductivity, the addition of BSA regulates MWCNTs-HFs hydrophobicity and biocompatibility, and better immobilizes GOD on MWCNTs-HFs. MWCNTs-BSA-HFs plays a synergistic role in the electrochemical response to glucose. The biosensor shows high sensitivity (167 μA·mM^-1·cm^-2), wide calibration range (0.01-3.5 mM), and low detection limit (17 μM). The apparent Michaelis-Menten constant Kmapp is 119 μM. Additionally, the proposed biosensor has good selectivity and excellent storage stability (120 days). The practicability of the biosensor was evaluated in real plasma samples, and the recovery rate was satisfactory.

Toxic Effect of Fullerene and Its Derivatives upon the Transmembrane β2-Adrenergic Receptors

Numerous experiments have revealed that fullerene (C₆₀) and its derivatives can bind to proteins and affect their biological functions. In this study, we explored the interaction between fullerine and the β₂-adrenergic receptor (β₂AR). The MD simulation results show that fullerene binds with the extracellular loop 2 (ECL2) and intracellular loop 2 (ICL2) of β₂AR through hydrophobic interactions and π–π stacking interactions. In the C₆₀_in1 trajectory, due to the π–π stacking interactions of fullerene molecules with PHE and PRO residues on ICL2, ICL2 completely flipped towards the fullerene direction and the fullerene moved slowly into the lipid membrane. When five fullerene molecules were placed on the extracellular side, they preferred to stack into a stable fullerene cluster (a deformed tetrahedral aggregate), and had almost no effect on the structure of β₂AR. The hydroxyl groups of fullerene derivatives (C₆₀(OH)_X, X represents the number of hydroxyl groups, X = 4, 8) can form strong hydrogen bonds with the ECL2, helix6, and helix7 of β₂AR. The hydroxyl groups firmly grasp the β₂AR receptor like several claws, blocking the binding entry of ligands. The simulation results show that fullerene and fullerene derivatives may have a significant effect on the local structure of β₂AR, especially the distortion of helix4, but bring about no great changes within the overall structure. It was found that C₆₀ did not compete with ligands for binding sites, but blocked the ligands’ entry into the pocket channel. All the above observations suggest that fullerene and its derivatives exhibit certain cytotoxicity.

Potential indicators of mitochondrial structure and function

Mitochondria regulate a range of important physiological and biochemical cellular processes including apoptotic cell death, energy production, calcium homeostasis, oxidative stress, and lipid metabolism. Given their role as the 'engines' of cells, their dysfunction is associated with a variety of disease states. Exploring the relationship between mitochondrial function and disease can reveal the mechanism(s) of drug activity and disease pathology. In this review, we summarized the methods of evaluating the structure and function of mitochondria, including the morphology, membrane fluidity, membrane potential, opening of the membrane permeability transition pore, inner membrane permeabilization, mitochondrial dynamics, mitophagy, oxidative stress, energy metabolism-related enzymes, apoptotic pathway related proteins, calcium concentration, DNA copy number, oxygen consumption, β-oxidation-related genes and proteins, cardiolipin content, and adenosine triphosphate content. We believe that the information presented in this review will help explore the pathological processes of mitochondria in the occurrence and development of diseases, as well as the activity and mechanism of drugs, and the discovery of new drugs.

The Imbalance of Mitochondrial Homeostasis of Peripheral Blood-Derived Macrophages Mediated by MAFLD May Impair the Walking Ability of Elderly Patients with Osteopenia

Introduction

Many Asian cohort studies have shown that nonalcoholic fatty liver disease (NAFLD), now renamed as metabolic dysfunction-associated fatty liver disease (MAFLD), increases the risk of osteoporosis, yet the effect of MAFLD on elderly patients with osteopenia (OPe) has not been reported.

Objective

This study aimed to explore the influence of MAFLD on the function of macrophages in patients with OPe.

Methods

A total of 107 elderly OPe patients with or without MAFLD who visited the Huadong Hospital Affiliated to Fudan University (Shanghai, China) between January 1st, 2021, and September 30th, 2021, were evaluated for an interviewer-assisted questionnaire, as well as clinical and biological assessments.

Results

Comparing two groups of elderly patients with the same bone mass level, we found that the six-minute walking distance (P = 0.012) and short physical performance battery (SPPB) score (P = 0.0029) of the elderly OPe patients with MAFLD are worse than those in OPe patients without MAFLD. Our results confirmed that the mitochondrial reactive oxygen species (mtROS) in peripheral blood of OPe patients with MAFLD was significantly higher than those without. We also observed the mitochondrial metabolism level of peripheral blood-derived macrophages in the included patients and peripheral blood macrophages in patients with MAFLD with more unbalanced mitochondrial dynamics of macrophages, more weakened mitochondrial respiratory capacity, and greater mitochondrial microstructure damage, when compared with the elderly patients without MAFLD.

Conclusions

To conclude, our data revealed that MAFLD itself may aggravate the inflammatory state in elderly OPe people due to mitochondrial homeostasis imbalance of peripheral blood macrophages. Damaged monocyte-macrophages might trigger attenuation of the walking ability of OPe patients.

Understanding the interactions between inorganic-based nanomaterials and biological membranes

The interactions between inorganic-based nanomaterials (NMs) and biological membranes are among the most important phenomena for developing NM-based therapeutics and resolving nanotoxicology. Herein, we introduce the structural and functional effects of inorganic-based NMs on biological membranes, mainly the plasma membrane and the endomembrane system, with an emphasis on the interface, which involves highly complex networks between NMs and biomolecules (such as membrane proteins and lipids). Significant efforts have been devoted to categorizing and analyzing the interaction mechanisms in terms of the physicochemical characteristics and biological effects of NMs, which can directly or indirectly influence the effects of NMs on membranes. Importantly, we summarize that the biological membranes act as platforms and thereby mediate NMs-immune system contacts. In this overview, the existing challenges and potential applications in the areas are addressed. A strong understanding of the discussed concepts will promote therapeutic NM designs for drug delivery systems by leveraging the NMs-membrane interactions and their functions.

Mesenchymal Stem Cells Differentiation: Mitochondria Matter in Osteogenesis or Adipogenesis Direction

Mesenchymal Stem Cells (MSCs) exhibit enormous therapeutic potential because of their indispensable regenerative, reparative, angiogenic, anti-apoptotic, and immunosuppressive properties. MSCs can best differentiate into mesodermal cell lineages, including osteoblasts, adipocytes, muscle cells, endothelial cells and chondrocytes. Specific differentiation of MSCs could be induced through limited conditions. In addition to the relevant differentiation factors, drastic changes also occur in the microenvironment to conduct it in an optimal manner for particular differentiation. Recent evidence suggests that the mitochondria participate in the regulating of direction and process of MSCs differentiation. Therefore, our current review focuses on how mitochondria participate in both osteogenesis and adipogenesis of MSC differentiation. Besides that, in our current review, we try to provide a further understanding of the relationship between the behavior of mitochondria and the direction of MSC differentiation, which could optimize current cellular culturing protocols for further facilitating tissue engineering by adjusting specific conditions of stem cells.

Antitumor Activity and Potential Mechanism of Novel Fullerene Derivative Nanoparticles

The development of novel nanoparticles as a new generation therapeutic drug platform is an active field of chemistry and cancer research. In recent years, fullerene nanoparticles have received extensive attention due to their unique physical and chemical properties. Properly modified fullerene nanoparticles have excellent biocompatibility and significant anti-tumor activity, which makes them have broad application prospects in the field of cancer therapy. Therefore, understanding the anti-tumor mechanism of fullerene nanoparticles is of great significance for the design and development of anti-tumor drugs with low toxicity and high targeting. This review has focused on various anti-tumor mechanisms of fullerene derivatives and discusses their toxicity and their distribution in organisms. Finally, the review points out some urgent problems that need solution before fullerene derivatives as a new generation of anti-tumor nano-drug platform enter clinical research.

A critical review on genotoxicity potential of low dimensional nanomaterials

Low dimensional nanomaterials (LDNMs) have earned attention among researchers as they exhibit a larger surface area to volume and quantum confinement effect compared to high dimensional nanomaterials. LDNMs, including 0-D and 1-D, possess several beneficial biomedical properties such as bioimaging, sensor, cosmetic, drug delivery, and cancer tumors ablation. However, they threaten human beings with the adverse effects of cytotoxicity, carcinogenicity, and genotoxicity when exposed for a prolonged time in industry or laboratory. Among different toxicities, genotoxicity must be taken into consideration with utmost importance as they inherit DNA related disorders causing congenital disabilities and malignancy to human beings. Many researchers have performed NMs' genotoxicity using various cell lines and animal models and reported the effect on various physicochemical and biological factors. In the present work, we have compiled a comparative study on the genotoxicity of the same or different kinds of NMs. Notwithstanding, we have included the classification of genotoxicity, mechanism, assessment, and affecting factors. Further, we have highlighted the importance of studying the genotoxicity of LDNMs and signified the perceptions, future challenges, and possible directives in the field.

Environmental risk of nanomaterials and nanoparticles and EPR technique as an effective tool to study them-a review

Nanotechnologies and different types of nanomaterials belong in present day to intensively studied materials due to their unique properties and diverse potential applications in, e.g., electronics, medicine, or display technologies. Together with the investigation of their desired beneficial properties, a need to investigate and evaluate their influence on the environment and possible harmful effects towards living organisms is growing. This review summarizes possible toxic effects of nanomaterials on environment and living organisms, focusing on the possible bioaccumulation in organisms, toxicity, and its mechanisms. The main goal of this review is to refer to potential environmental risks rising from the use of nanomaterials and the necessity to deal with the possible toxic effects considering the growing interest in the wide-scale utilization of these materials. Electron paramagnetic resonance spectroscopy as the only analytical technique capable of detecting radical species enables detection, quantification, and monitoring of the generation of short-lived radicals often coupled with toxic effects of nanomaterials, which makes it an important method in the process of nanotoxicity mechanism determination.

Ex vivo interaction study of NaYF4 :Yb,Er nanophosphors with isolated mitochondria

Ex vivo interaction of NaYF₄ :Yb,Er nanophosphors with isolated mitochondria has been investigated. The nanophosphors were synthesized using the hydrothermal method. The synthesized NaYF₄ :Yb,Er nanophosphors were characterized for physicochemical properties. The NaYF₄ :Yb,Er nanophosphors showed successful upconversion with excitation wavelength lying in the near-infrared region. The effect of synthesized NaYF₄ :Yb,Er nanophosphors on mitochondria isolated from the chicken heart tissue was examined through ROS generation capacity, membrane fluidity, and complex II activity. The exposer of NaYF₄ :Yb,Er nanophosphors to isolated mitochondria inhibits ROS generation activity as compared to control. The mitochondria membrane fluidity of the lipid bilayer and complex-II activity of mitochondria was observed to be unaltered after the interaction with NaYF₄ :Yb,Er nanoparticles. The results confirm that synthesized NaYF₄ :Yb,Er nanoparticles can be used as a safe contrast agent.

A Protein and Membrane Integrity Study of TiO2 Nanoparticles-Induced Mitochondrial Dysfunction and Prevention by Iron Incorporation

The paper assessed the toxic effect of titanium dioxide (TiO₂) nanoparticles (NPs) on isolated mitochondria and its dysfunction prevention after Iron (Fe) incorporation. TiO₂ and Fe content TiO₂ NPs were synthesized and characterized using XPS, PL spectroscopy, and TEM. The nanostructure interaction with isolated mitochondria was investigated using circular dichroism (CD) confocal microscopy, flow cytometry, atomic force microscopy (AFM), surface-enhanced Raman spectroscopy (SERS), and FT-IR spectroscopy via nonspecific pathway. Fe content TiO₂ NPs helps to control the dissolution rate of parent nanomaterial of TiO₂ on the mitochondrial membrane. Confocal micrographs and flow cytometry results confirmed that Rhodamine 123 dye intensity get increased after interaction with Fe content TiO₂ NPs which states the integrity of the mitochondrial membrane. AFM results revealed that TiO₂ induces the swelling of mitochondrial tubules and also impaired the mitochondrial structure, whereas Fe content TiO₂ NPs interaction prevents the impairment of mitochondrial tubules. The denaturation of a membrane protein by TiO₂ interactions was observed through CD Spectroscopy. Further, nano-bio-interface study was performed using SERS, through shifting and extinct of peaks affiliated to membrane proteins and lipids. However, Fe content TiO₂-treated samples showed a significant increase in the membrane potential of mitochondria via flow cytometry results.

Acute exposure to C60 fullerene damages pulmonary mitochondrial function and mechanics

C60 fullerene (C60) nanoparticles, a nanomaterial widely used in technology, can offer risks to humans, overcome biological barriers, and deposit onto the lungs. However, data on its putative pulmonary burden are scanty. Recently, the C60 interaction with mitochondria has been described in vitro and in vivo. We hypothesized that C60 impairs lung mechanics and mitochondrial function. Thirty-five male BALB/c mice were randomly divided into two groups intratracheally instilled with vehicle (0.9% NaCl + 1% Tween 80, CTRL) or C60 (1.0 mg/kg, FUL). Twenty-four hours after exposure, 15 FUL and 8 CTRL mice were anesthetized, paralyzed, and mechanically ventilated for the determination of lung mechanics. After euthanasia, the lungs were removed en bloc at end-expiration for histological processing. Lung tissue elastance and viscance were augmented in FUL group. Increased inflammatory cell number, alveolar collapse, septal thickening, and pulmonary edema were detected. In other six FUL and six CTRL mice, mitochondria expressed reduction in state 1 respiration [FUL = 3.0 ± 1.14 vs. CTRL = 4.46 ± 0.9 (SEM) nmol O₂/min/mg protein, p = 0.0210], ATP production (FUL = 122.6 ± 18 vs. CTRL = 154.5 ± 14 μmol/100 μg protein, p = 0.0340), and higher oxygen consumption in state 4 [FUL = 12.56 ± 0.9 vs. CTRL = 8.26 ± 0.6], generation of reactive oxygen species (FUL 733.1 ± 169.32 vs. CTRL = 486.39 ± 73.1 nmol/100 μg protein, p = 0.0313) and reason ROS/ATP [FUL = 8.73 ± 2.3 vs. CTRL = 2.99 ± 0.3]. In conclusion, exposure to fullerene C60 impaired pulmonary mechanics and mitochondrial function, increased ROS concentration, and decrease ATP production.

Effects of nanosilver on hematologic, histologic and molecular parameters of rainbow trout (Oncorhynchus mykiss)

Efficient antibacterial and antifungal properties of silver nanoparticles (AgNPs) sparked its commercial application in several industrial and household products. Drastic increase of AgNPs production raised concerns over aquatic organisms' exposure. The toxic dose, mechanism of toxicity, physiological damages, gene expression alteration, hematological and blood parameter distortion by AgNP needs to be investigated to explore inevitable risk in aquatic animals. In this study, rainbow trout (Oncorhynchus mykiss) (122.4 ± 1.4 g, 23.8 ± 0.7 cm) were exposed to colloidal AgNPs (28.3 ± 12.6 um) to determine the lethal concentration (LC50)(8.9 mg/l). Sub-lethal concentrations (10 %LC50, 25 %LC50, plus LC50 value) impact on hematologic, histological and molecular responses were evaluated. Results showed sever damage to blood cells morphology, and hematologic parameters change including RBC, WBC, Hct and Hb in all AgNP-treated groups. Histological damage in gill and liver of exposed fish were observed. Significant up-regulating of HSP70 and P53 genes were detected in response to AgNPs, whereas, it was found that in comparison to HSP70 gene, P53 induction occurred in lower AgNPs concentrations and lower exposure time. These results indicate adversely effects of AgNPs exposure to aquatic environments.

A Multiparametric Study of Internalization of Fullerenol C60(OH)36 Nanoparticles into Peripheral Blood Mononuclear Cells: Cytotoxicity in Oxidative Stress Induced by Ionizing Radiation

The aim of this study was to investigate the uptake and accumulation of fullerenol C₆₀(OH)₃₆ into peripheral blood mononuclear cells (PBMCs). Some additional studies were also performed: measurement of fullerenol nanoparticle size, zeta potential, and the influence of fullerenol on the ionizing radiation-induced damage to PMBCs. Fullerenol C₆₀(OH)₃₆ demonstrated an ability to accumulate in PBMCs. The accumulation of fullerenol in those cells did not have a significant effect on cell survival, nor on the distribution of phosphatidylserine in the plasma membrane. However, fullerenol-induced depolarization of the mitochondrial membrane proportional to the compound level in the medium was observed. Results also indicated that increased fullerenol level in the medium was associated with its enhanced transport into cells, corresponding to its influence on the mitochondrial membrane. The obtained results clearly showed the ability of C₆₀(OH)₃₆ to enter cells and its effect on PBMC mitochondrial membrane potential. However, we did not observe radioprotective properties of fullerenol under the conditions used in our study.

Inhibition of Autophagy via Lysosomal Impairment Enhances Cytotoxicity of Fullerenol under Starvation Condition

Autophagy is well-known as a common cellular response to nanomaterials. As one of the most comprehensively studied carbon-based nanomaterials, fullerene and its derivatives have been reported to bring about autophagic features in various cell lines, but little is known about the role of fullerenol (C₆₀(OH)₄₄) on the modulation of autophagy in human gastric tumor cell line SGC-7901. Fullerenol treatment led to the accumulation of autophagosomes, as evidenced by the increased fluorescent intensity of monodansylcadaverine (MDC) staining cells, an elevated level of LC3 protein, and the observation of auotphagosomes in cytoplasm. Subsequent results of the p62 level demonstrated that the accumulation of autophagosomes resulted from the blockade of autophagic flux rather than the activation of autophagy. Fullerenol disrupted autophagic flux by impairing lysosomal function, including lysosome membrane permeabilization (LMP), alkaline of lysosomes, and reduced activity of capthesin B. Interestingly, fullerenol treatment was noncytotoxic under a nutrient-rich condition. When serum was deprived, cytotoxicity occurred in a concentration- and time-dependent manner, along with massive vacuoles in cytoplasm, a large amount of ROS generation, and finally cell death, which can be ascribed to the disruption of essential autophagy in cells. Taken together, understanding this autophagy-lysosome pathway will shed light on the potential anticancer application of fullerenol.

Mitochondrial toxicity of nanomaterials

In recent years, nanomaterials have been widely applied in electronics, food, biomedicine and other fields, resulting in increased human exposure and consequent research focus on their biological and toxic effects. Mitochondria, the main target organelle for nanomaterials (NM), play a critical role in their toxic activities. Several studies to date have shown that nanomaterials cause alterations in mitochondrial morphology, mitochondrial membrane potential, opening of the mitochondrial permeability transition pore (MPTP) and mitochondrial respiratory function, and promote cytochrome C release. An earlier mitochondrial toxicity study of NMs additionally reported induction of mitochondrial dynamic changes. Here, we have reviewed the mitochondrial toxicity of NMs and provided a scientific basis for the contribution of mitochondria to the toxicological effects of different NMs along with approaches to reduce mitochondrial and, consequently, overall toxicity of NMs.

Bidirectional Regulatory Mechanisms of Jaceosidin on Mitochondria Function: Protective Effects of the Permeability Transition and Damage of Membrane Functions

Many natural products could induce apoptosis through mitochondrial pathways. However, direct interactions between natural products and mitochondria have rarely been reported. In this work, the effects and regulatory mechanisms of Jaceosidin on the isolated rat liver mitochondria have been studied. The results of the experiments which by introducing exogenous Ca²⁺ illustrated that Jaceosidin has the protective effects on the structure and function of the isolated mitochondria. These protective effects were related to the chelation of Ca²⁺ with Jaceosidin. Besides, Jaceosidin could scavenge reactive oxygen species produced during electron transport, and weaken the mitochondrial lipid peroxidation rate, which may be attributed to the antioxidant effect of phenolic hydroxyl groups of Jaceosidin. In addition, Jaceosidin has some damage effects on mitochondrial function, such as the inhibition of mitochondrial respiration and the increase of mitochondrial membrane fluidity. These results of this work provided comprehensive information to clarify the mechanisms of Jaceosidin on mitochondria, which may be the bidirectional regulatory mechanisms.

Study of mitochondrial swelling, membrane fluidity and ROS production induced by nano-TiO2 and prevented by Fe incorporation

The potential impact of TiO2 and Fe incorporated TiO2 nanoparticles at the organelle level has been reported. The toxicity of the samples on mitochondria isolated from chicken liver tissue has been examined through mitochondrial swelling, membrane fluidity, ROS generation capacity, and activity of complex II. The toxic effect of TiO2 was prevented by incorporating Fe into the TiO2 matrix at different concentrations. The activity of the succinate dehydrogenase enzyme complex was affected and permeabilization of the mitochondrial inner membrane to H+ and K+ and its alteration in membrane fluidity at 100 μg mL-1 of nano-TiO2 dosage were investigated, which showed significant changes in the anisotropy of DPH-labeled mitochondria. Fe incorporation into the TiO2 matrix makes it more biocompatible by changing its structure and morphology.

Effect of TiO2 and Fe doped TiO2 nanoparticles on mitochondrial membrane potential in HBL-100 cells

Titanium dioxide (TiO₂) nanoparticles (NPs) have made unbelievable progress in the field of nanotechnology and biomedical research. The proper toxicological assessment of TiO₂ NPs and the reduction of its cytotoxicity need to be addressed. Fe doping in TiO₂ has been investigated to reduce the toxic effects of TiO₂ NPs. Fe doped TiO₂ powder samples were synthesized by sol-gel methods. The prepared samples were characterized by x-ray diffractometer (XRD), transmission electron microscope (TEM), and Raman spectroscopy to study their structure, morphology, and molecular conformation. XRD results revealed the coexistence of anatase (A) and rutile (R) phases of TiO₂. The A-R transformation was observed with an increase in Fe doping along with the formation of α-Fe₂O₃ phase. TEM showed changes in morphology from spherical nanoparticles to elongated rod-shaped nanostructures with increasing Fe content. Shape variation of TiO₂ nanoparticles after incorporation of Fe is a key reason behind the toxicity reduction. The authors observed that the toxicity of TiO₂ nanoparticles was rescued upon Fe incorporation. The effect of NPs on the mitochondrial membrane potential (MMP) was assessed using flow cytometry. The MMP (%) decreased in TiO₂ treated cells and increased by 1% Fe doped TiO₂ NPs treated cells. Confocal imaging revealed the presence of functional mitochondria upon the exposure of Fe doped TiO₂ NPs. The goal of the present study was to decrease the toxic effects induced by TiO₂ NPs on mitochondrial potential and its prevention by Fe doping.

Toxic effects and involved molecular pathways of nanoparticles on cells and subcellular organelles

Owing to the increasing application of engineered nanoparticles (NPs), besides the workplace, human beings are also exposed to NPs from nanoproducts through the skin, respiratory tract, digestive tract and vein injection. This review states pathways of cellular uptake, subcellular distribution and excretion of NPs. The uptake pathways commonly include phagocytosis, micropinocytosis, clathrin- and caveolae-mediated endocytosis, scavenger receptor-related pathway, clathrin- or caveolae-independent pathway, and direct penetration or insertion. Then the ability of NPs to decrease cell viability and metabolic activity, change cell morphology, and destroy cell membrane, cytoskeleton and cell function was presented. In addition, the lowest dose decreasing cell metabolic viability compared with the control or IC₅₀ of silver, titanium dioxide, zinc oxide, carbon black, carbon nanotubes, silica, silicon NPs and cadmium telluride quantum dots to some cell lines was gathered. Next, this review attempts to increase our understanding of NP-caused adverse effects on organelles, which have implications in mitochondrial dysfunction, endoplasmic reticulum stress and lysosomal rupture. In particular, the disturbance of mitochondrial biogenesis and mitochondrial dynamic fusion-fission, mitophagy and cytochrome c-dependent apoptosis are involved. In addition, prolonged endoplasmic reticulum stress will result in apoptosis. Rupture of the lysosomal membrane was associated with inflammation, and both induction of autophagy and blockade of autophagic flow can result in cytotoxicity. Finally, the network mechanism of the combined action of multiple organelle dysfunction, apoptosis, autophagy and oxidative stress was discussed.

Antagonistic Interactions between Benzo[a]pyrene and Fullerene (C60) in Toxicological Response of Marine Mussels

This study aimed to assess the ecotoxicological effects of the interaction of fullerene (C60) and benzo[a]pyrene (B[a]P) on the marine mussel, Mytilus galloprovincialis. The uptake of nC60, B[a]P and mixtures of nC60 and B[a]P into tissues was confirmed by Gas Chromatography-Mass Spectrometry (GC-MS), Liquid Chromatography-High Resolution Mass Spectrometry (LC-HRMS) and Inductively Coupled Plasma Mass Spectrometer (ICP-MS). Biomarkers of DNA damage as well as proteomics analysis were applied to unravel the interactive effect of B[a]P and C60. Antagonistic responses were observed at the genotoxic and proteomic level. Differentially expressed proteins (DEPs) were only identified in the B[a]P single exposure and the B[a]P mixture exposure groups containing 1 mg/L of C60, the majority of which were downregulated (~52%). No DEPs were identified at any of the concentrations of nC60 (p < 0.05, 1% FDR). Using DEPs identified at a threshold of (p < 0.05; B[a]P and B[a]P mixture with nC60), gene ontology (GO) and Kyoto encyclopedia of genes and genomes (KEGG) pathway analysis indicated that these proteins were enriched with a broad spectrum of biological processes and pathways, including those broadly associated with protein processing, cellular processes and environmental information processing. Among those significantly enriched pathways, the ribosome was consistently the top enriched term irrespective of treatment or concentration and plays an important role as the site of biological protein synthesis and translation. Our results demonstrate the complex multi-modal response to environmental stressors in M. galloprovincialis.

In vitro modulation of mercury-induced rat liver mitochondria dysfunction

Mercury (Hg) is a toxic environmental pollutant that exerts its cytotoxic effects as cations by targeting mitochondria. In our work, we determined different mitochondrial toxicity factors using specific substrates and inhibitors following the addition of Hg2+ to the mitochondria isolated from Wistar rat liver in vitro. We found that Hg2+ induced marked changes in the mitochondrial ultrastructure accompanied by mitochondrial swelling, mitochondrial membrane potential collapse, mitochondrial membrane fluidity increase and Cytochrome c release. Additionally, the effects of Hg2+ on heat production of mitochondria were investigated using microcalorimetry; simultaneously, the effects on mitochondrial respiration were determined by Clark oxygen-electric methods. Microcalorimetry could provide detailed kinetic and thermodynamic information which demonstrated that Hg2+ had some biotoxicity effect on mitochondria. The inhibition of energy metabolic activities suggested that high concentrations of Hg2+ could induce mitochondrial ATP depletion under MPT and mitochondrial respiration inhibition. These results help us learn more about the toxicity of Hg2+ at the subcellular level.

Mitochondrial morphology and function impaired by dimethyl sulfoxide and dimethyl Formamide

In this work, the effects of two non-ionic, non-hydroxyl organic solvents, dimethyl sulfoxide (DMSO) and dimethyl formamide (DMF) on the morphology and function of isolated rat hepatic mitochondria were investigated and compared. Mitochondrial ultrastructures impaired by DMSO and DMF were clearly observed by transmission electron microscopy. Spectroscopic and polarographic results demonstrated that organic solvents induced mitochondrial swelling, enhanced the permeation to H⁺/K⁺, collapsed the potential inner mitochondrial membrane (IMM), and increased the IMM fluidity. Moreover, with organic solvents addition, the outer mitochondrial membrane (OMM) was broken, accompanied with the release of Cytochrome c, which could activate cell apoptosis signaling pathway. The role of DMSO and DMF in enhancing permeation or transient water pore formation in the mitochondrial phospholipid bilayer might be the main reason for the mitochondrial morphology and function impaired. Mitochondrial dysfunctions induced by the two organic solvents were dose-dependent, but the extents varied. Ethanol (EtOH) showed the highest potential damage on the mitochondrial morphology and functions, followed by DMF and DMSO.

Hepatoprotective effect of fullerenol/doxorubicin nanocomposite in acute treatment of healthy rats

In our recent studies we have designed fullerenol/doxorubicin nanocomposite (FNP/DOX) as the new drug nanocarrier. This research has demonstrated that this novel nanocomposite has had better implications on the liver tissue in vivo (Wistar rats treated intraperitoneally), than treatment based only on DOX. FNP/DOX has been characterised by DLS, TEM and AFM measurements which have shown that DOX loaded onto FNP did not influence fullerenol nanoparticle's size. FNP/DOX affected oxidative status in blood causing a significant decrease of catalase and SOD activity in comparison to DOX, implicating the reduction in oxidative stress. qRT-PCR results on the mRNA level of antioxidative enzymes (catalase and MnSOD) revealed that the effect of oxidative stress is significantly reduced by the treatment with FNP/DOX (p < .05). The ultrastructural analysis of the liver tissue has revealed that FNP/DOX nanocomposite generated considerably less damage in the liver tissue, than DOX applied at the same dose. Hence, our results have indicated that FNP, within FNP/DOX nanocomposite, exhibits protective effects to the liver tissue of the healthy rats.

Carbon black suppresses the osteogenesis of mesenchymal stem cells: the role of mitochondria

BACKGROUND

The rapid increase in carbon black poses threats to human health. We evaluated the effect of CB (Printex 90) on the osteogenesis of bone-marrow-derived mesenchymal stem cells (MSCs). Mitochondria play an important role in the osteogenesis of MSCs and are potential targets of nanomaterials, so we studied the role of mitochondria in the CB Printex 90-induced effects on osteogenesis.

RESULTS

Low doses of Printex 90 (3 ng/mL and 30 ng/mL) that did not cause deleterious effects on MSCs' viability significantly inhibited osteogenesis of MSCs. Printex 90 caused down-regulation of osteoblastic markers, reduced activity of alkaline phosphatase (ALP), and poor mineralization of osteogenically induced MSCs. Cellular ATP production was decreased, mitochondrial respiration was impaired with reduced expression of ATPase, and the mitochondrial membrane was depolarized. The quantity and quality of mitochondria are tightly controlled by mitochondrial biogenesis, mitochondrial dynamics and mitophagy. The transcriptional co-activator and transcription factors for mitochondrial biogenesis, PGC-1α, Nrf1 and TFAM, were suppressed by Printex 90 treatment, suggesting that decreased biogenesis was caused by Printex 90 treatment during osteogenesis. Mitochondrial fusion and fission were significantly inhibited by Printex 90 treatment. PINK1 accumulated in Printex 90-treated cells, and more Parkin was recruited to mitochondria, indicating that mitophagy increased to remove the damaged mitochondria.

CONCLUSIONS

This is the first report of the inhibitory effects of CB on the osteogenesis of MSCs and the involvement of mitochondria in CB Printex 90-induced suppression of MSC osteogenesis.

Metabolic Responses of Mytilus galloprovincialis to Fullerenes in Mesocosm Exposure Experiments

In this study, Mediterranean mussels (Mytilus galloprovincialis) were exposed through the diet to fullerene soot at three concentrations in parallel to a control group. Their metabolomics response was assessed by high-performance liquid chromatography coupled to high-resolution mass spectrometry (HPLC-HRMS). The experiments were conducted in marine mesocosms, during 35 days (7 days of acclimatization, 21 days of exposure, and 7 days of depuration). Real conditions were emulated in terms of physicochemical conditions of the habitat. Results confirmed the bioaccumulation of fullerenes, and the metabolome of the exposed organisms revealed significant differences in the concentrations of seven free amino acids in comparison to the control group. An increase in small nonpolar amino acids (e.g., alanine) and branched chain amino acids (leucine and isoleucine) were observed. Also, glutamine concentrations decreased significantly, suggesting the activation of facultative anaerobic energy metabolism. Branched chain amino acids, such as leucine and isoleucine, followed the opposite trend after the highest level of exposure, which can imply hormesis effects. Other significant differences were observed on lipids content, such as the general increase of free fatty acids, i.e., long-chain fatty acids (lauric, myristic, and palmitic acids) when the concentration of exposure was increased. These results were consistent with hypoxia and oxidative stress.

Mitochondrial toxicity of organic arsenicals: membrane permeability transition pore opening and respiratory dysfunction

In order to clarify the mitochondrial toxicity mechanism of the organic arsenical MOPIMP (2-methoxy-4-(((4-(oxoarsanyl) phenyl) imino) methyl) phenol), research was carried out at the sub-cell level based on the previous finding that the compound MOPIMP can damage the mitochondria by triggering a burst of ROS. After investigating its influence on isolated mitochondria in vitro, it was demonstrated that a high dose of MOPIMP with short-term exposure can induce mitochondrial swelling, decrease the membrane potential, enhance the permeability of H⁺ and K⁺, and induce membrane lipid peroxidation, indicating that it can result in an MPT process in a ROS-mediated and Ca²⁺-independent manner. Additionally, MPT was also aggravated as a result of impairment of the membrane integrity and membrane fluidity. In addition, short-term incubation between mitochondria and compound MOPIMP promoted the inhibition of respiratory chain complexes I, II, III and IV, as well as damage to the respiration process, which supported the previous finding about the burst of ROS. On the other hand, after long-term exposure by the organic arsenical MOPIMP, mitochondrial metabolic dysfunction was triggered, which was in accordance with perturbation of the respiratory chain complexes as well as the respiration process. This work systematically sheds light on the mitochondrial toxicity mechanism of the organic arsenical MOPIMP, including induction of the MPT process and inhibition of respiratory metabolism, which provides a potential target for organic arsenicals as anti-tumor drugs.

Toxicity of Pb2+ on rat liver mitochondria induced by oxidative stress and mitochondrial permeability transition

Pb2+ exposure in humans occurs mainly through air inhalation, food and water uptake which has been shown to be generally associated with numerous body functions such as the central and peripheral nervous systems, the red blood cells, the kidneys and the liver. It has been reported that the liver is the storage site and an important primary target in Pb2+ toxicity, and the hepatotoxicity of Pb2+ could be resulted from the impairment of the liver mitochondria. In this study, several mitochondrial dysfunctions following the addition of Pb2+ (10-160 μM) were investigated. We found that Pb2+ inhibited the enzyme activities of mitochondrial respiratory complexes and complex III was the major source of Pb2+-induced significant reactive oxygen species (ROS) formation. As a consequence, our results showed that Pb2+ induced significant progress in mitochondrial lipid peroxidation, adenosine triphosphate (ATP) consumption and glutathione (GSH) oxidation. On the other hand, Pb2+ induced marked changes in mitochondrial permeability transition (MPT) accompanied by mitochondrial swelling, mitochondrial membrane potential collapse, mitochondrial membrane fluidity decrease and cytochrome c (Cyt c) release. Additionally, several mitochondrial MPT inhibitors and chelators were utilized to determine the possible interaction sites of Pb2+ on mitochondria. In general, our data supported that the Pb2+-induced liver toxicity was a result of the disruptive effect on the mitochondrial respiratory complexes. This disruptive effect caused oxidative stress and MPT, which led to mitochondrial dysfunctions and even cell death signalling via mitochondrial permeability transition pore (MPTP) opening and Cyt c release.

The relationship between the length of surface ligand and effects of CdTe quantum dots on the physiological functions of isolated mitochondria

The potential toxicity of Quantum dots (QDs) should be assessed comprehensively for their fast spreading applications. Many studies have shown the toxicity of QDs is associated with their surface ligands. In this work, two analog ligands with one carbon difference, 2-mercaptoacetic acid (TGA) and 3-mercaptopropionic acid (MPA) were used as coating materials in the syntheses of two types of CdTe QDs with similar physicochemical properties. Then the biological effects of QDs on isolated mitochondria were studied. It was found that the two types of QDs could impair mitochondrial respiration and induce mitochondrial permeability transition (MPT). However, as compared with TGA-CdTe QDs, MPA-CdTe QDs had a stronger effect on MPT. The weaker effect of TGA-CdTe QDs on MPT might be owing to their better stability and thus less amount of released Cd²⁺, which could be further explained by the stronger affinity between the ligand (TGA) and the cadmium complexes in the crystal growth of QDs. These results highlighted the importance of ligands responsible for the toxicity of QDs at the sub-cellular level.

Silver ion-induced mitochondrial dysfunction via a nonspecific pathway

Silver, once regarded as a safe noble metal for humans, has been widely used in industrial and commercial products, especially in nanometer biomaterials. It is now well known that Ag+ is biologically active and is able to interact with the cell membrane, proteins and DNA. However, very little is understood about the potential impacts of Ag+ at the sub-cellular level. Our work investigated the potential toxicity of Ag+ on mitochondria isolated from rat livers by examining the mitochondrial morphology, respiration, swelling, membrane fluidity and reactive oxygen species (ROS) generation. We observed that Ag+ significantly affects the mitochondrial structure and function, including mitochondrial swelling, collapse of the transmembrane potential, change of permeability and fluidity, decline of the respiratory rate, and acceleration of ROS, indicating that Ag+ should be seriously regarded as a potentially hazardous substance. Moreover, we conclude that Ag+ injures the mitochondrial structure and function by a nonspecific approach, in which the interaction is unregulated by inherent parts such as the mitochondria permeability transition pore (MPTP). These results help us learn more about the toxicity of Ag+ at the subcellular (mitochondrial) level and influence future biological and medical applications of Ag-based materials.

Fullerenes in Biology and Medicine

Fullerenes and related carbon based derivatives have shown a growing relevance in biology and medicine, mainly due to the unique electronic and structural properties that make them excellent candidates for multiple functionalization. This review focuses on the most recent developments of fullerene derivatives for different biological applications.

Characterization of fullerenol-protein interactions and an extended investigation on cytotoxicity

Fullerenols, known as polyhydroxylated derivatives of fullerene, have attracted great attention due to their distinctive material properties and potential applications in biology and medicine. As a step toward the elucidation of basic behavior in biological systems, a variety of spectroscopic measurements as well as isothermal titration calorimetry (ITC) were applied to study the interaction between fullerenol (C₆₀(OH)₄₄) and serum proteins (bovine serum albumin (BSA) and γ-globulins). The results of fluorescence spectra indicated that the intrinsic fluorescence of proteins could be effectively quenched by the dynamic mechanism. The affinity values of both proteins bound to fullerenol were of the same order of magnitude. Meanwhile, ITC results showed that the interaction between fullerenol and BSA was enthalpy favorable, while the interaction with γ-globulins was enthalpy unfavorable. Furthermore, fullerenol had little influence on the secondary structure of both proteins. Additional cytotoxicity tests showed that the presence of proteins attenuated the toxic effect of fullerenol on human normal gastric epithelial cell line (GES-1). Thus, the interaction between fullerenol and proteins is indispensable to evaluate the biosafety of fullerenol, which may in turn promotes the development of its biological applications.

Spectroscopic, Polarographic, and Microcalorimetric Studies on Mitochondrial Dysfunction Induced by Ethanol

Liver mitochondria are involved in several important life processes; mitochondrial dysfunction and disorders are implicated in several human diseases. Alcohol permeates all tissues of the body and exerts some intrinsic hepatotoxicity. In this work, our results demonstrated that ethanol caused a series of mitochondria permeability transition pore (MPTP) opening factors such as mitochondrial swelling, increased permeability of H⁺ and K⁺, collapsed membrane potential, and increased membrane fluidity. Furthermore, mitochondrial ultrastructure alternation observed clearly by transmission electron microscopy and the release of Cytochrome c could explain the MPTP opening from another aspect. Moreover, ethanol damaged the mitochondrial respiration system and induced disturbance of mitochondrial energy metabolism which was monitored by polarographic and microcalorimetric methods, respectively. Considered together, these damages may promote both apoptotic and necrotic cell death and contribute to the onset or progression alcohol-induced liver diseases.

Engineered nanomaterial-induced lysosomal membrane permeabilization and anti-cathepsin agents

Engineered nanomaterials (ENMs), or small anthropogenic particles approximately < 100 nm in size and of various shapes and compositions, are increasingly incorporated into commercial products and used for industrial and medical purposes. There is an exposure risk to both the population at large and individuals in the workplace with inhalation exposures to ENMs being a primary concern. Further, there is increasing evidence to suggest that certain ENMs may represent a significant health risk, and many of these ENMs exhibit distinct similarities with other particles and fibers that are known to induce adverse health effects, such as asbestos, silica, and particulate matter (PM). Evidence regarding the importance of lysosomal membrane permeabilization (LMP) and release of cathepsins in ENM toxicity has been accumulating. The aim of this review was to describe our current understanding of the mechanisms leading to ENM-associated pathologies, including LMP and the role of cathepsins with a focus on inflammation. In addition, anti-cathepsin agents, some of which have been tested in clinical trials and may prove useful for ameliorating the harmful effects of ENM exposure, are examined.

Effect of PGC-1α overexpression or silencing on mitochondrial apoptosis of goat luteinized granulosa cells

During goat follicular development, abnormal expression of peroxisome proliferator- activated receptor gamma coactivator-1 alpha (PGC-1α) in granulosa cells (GCs) may contribute to follicular atresia with unknown regulatory mechanisms. In this study, we investigate the effect of ectopic expression or interference of PGC-1α on cell apoptosis of goat first passage granulosa cells (FGCs) in vitro. The results indicate that PGC-1α silencing by short hairpin RNA (shRNA) in goat FGCs significantly reduced mitochondrial DNA (mtDNA) copy number (P < 0.05), changed mitochondria ultrastructure, and induced cell apoptosis (P < 0.05). The transcription and translation levels of the apoptosis-related genes BCL-2-associated X protein (BAX), caspase 3, and caspase 9 were significantly up-regulated (P < 0.05, respectively). Moreover, the ratio of BAX/B-cell lymphoma 2 (BCL-2) was reduced (P < 0.05), and the release of cytochrome c (cyt c) and lactate dehydrogenase (LDH) was significantly enhanced (P < 0.05, respectively) in PGC-1α interference goat FGCs. Furthermore, the expression of anti-oxidative related genes superoxide dismutase 2 (SOD2), glutathione peroxidase (GPx) and catalase (CAT) was down-regulated (P < 0.05, respectively) and the activity of glutathione/glutathione disulfide (GSH/GSSG) was inhibited (P < 0.05). While enforced expression of PGC-1α increased the levels of genes involved in the regulation of mitochondrial function and biogenesis, and enhanced the anti-oxidative and anti-apoptosis capacity. Taken together, our results reveal that lack of PGC-1α may lead to mitochondrial dysfunction and disrupt the cellular redox balance, thus resulting in goat GCs apoptosis through the mitochondria-dependent apoptotic pathway.

Microcalorimetric studies on the energy release of isolated rat mitochondria under different concentrations of gadolinium (III)

Gadolinium-based compounds are most widely utilized for paramagnetic contrast agents, but, the toxicological mechanism of gadolinium (Gd) had not been fully elucidated since the first report about Gd anomaly. In this work, we analyzed the effect of Gd(3+) on mitochondria in vitro by microcalorimetry. Microcalorimetry can provide detailed kinetic and thermodynamic information from thermogenic curve. At the tested concentration, Gd(3+) induced the increase of growth rate constant (k1). At high concentration (100-500 μM), the maximum power output time (tm), the decline rate constant (-k2) and the time of activity recovery phase (tR) decreased with the addition of Gd(3+) and the maximum power output (Pm) increased. At low concentration (0-100 μM), the changes were different from high concentration. From the results we concluded that the effect of different concentrations of Gd(3+) had a relationship with time, high concentration of Gd(3+) induced mitochondrial energy metabolism disturb however low concentration may promote mitochondrial adaption to physiological stresses. The effect of low concentration of Gd(3+) need more work to elucidate the mechanism. The results of total heat output (Q) and mitochondrial respiratory activities suggested high concentrations of Gd(3+) could accelerate adenosine triphosphate (ATP) consumption under respiratory system damaged.

Mitochondrial dysfunction induced by ultra-small silver nanoclusters with a distinct toxic mechanism

As noble metal nanoclusters (NCs) are widely employed in nanotechnology, their potential threats to human and environment are relatively less understood. Herein, the biological effects of ultra-small silver NCs coated by bovine serum albumin (BSA) (Ag-BSA NCs) on isolated rat liver mitochondria were investigated by testing mitochondrial swelling, membrane permeability, ROS generation, lipid peroxidation and respiration. It was found that Ag-BSA NCs induced mitochondrial dysfunction via synergistic effects of two different ways: (1) inducing mitochondrial membrane permeability transition (MPT) by interacting with the phospholipid bilayer of the mitochondrial membrane (not with specific MPT pore proteins); (2) damaging mitochondrial respiration by the generation of reactive oxygen species (ROS). As far as we know, this is the first report on the biological effects of ultra-small size nanoparticles (∼2 nm) at the sub-cellular level, which provides significant insights into the potential risks brought by the applications of NCs. It would inspire us to evaluate the potential threats of nanomaterials more comprehensively, even though they showed no obvious toxicity to cells or in vivo animal models. Noteworthy, a distinct toxic mechanism to mitochondria caused by Ag-BSA NCs was proposed and elucidated.