Cerium oxide nanoparticles inhibit adipogenesis in rat mesenchymal stem cells: potential therapeutic implications

Redox Biology in Adipose Tissue Physiology and Obesity

Reactive oxygen species (ROS), a by-product of mitochondrial oxidative phosphorylation and cellular metabolism, is vital for cellular survival, proliferation, damage, and senescence. In recent years, studies have shown that ROS levels and redox status in adipose tissue are strongly associated with obesity and metabolic diseases. Although it was previously considered that excessive production of ROS and impairment of antioxidant capability leads to oxidative stress and potentially contributes to increased adiposity, it has become increasingly evident that an adequate amount of ROS is vital for adipocyte differentiation and thermogenesis. In this review, by providing a systematic overview of the recent understanding of the key factors of redox systems, endogenous mechanisms for redox homeostasis, advanced techniques for dynamic redox monitoring, as well as exogenous stimuli for redox production in adipose tissues and obesity, the importance of redox biology in metabolic health is emphasized.

Oxygen in Metabolic Dysfunction and Its Therapeutic Relevance

Significance: In recent years, a number of studies have shown altered oxygen partial pressure at a tissue level in metabolic disorders, and some researchers have considered oxygen to be a (macro) nutrient. Oxygen availability may be compromised in obesity and several other metabolism-related pathological conditions, including sleep apnea-hypopnea syndrome, the metabolic syndrome (which is a set of conditions), type 2 diabetes, cardiovascular disease, and cancer. Recent Advances: Strategies designed to reduce adiposity and its accompanying disorders have been mainly centered on nutritional interventions and physical activity programs. However, novel therapies are needed since these approaches have not been sufficient to counteract the worldwide increasing rates of metabolic disorders. In this regard, intermittent hypoxia training and hyperoxia could be potential treatments through oxygen-related adaptations. Moreover, living at a high altitude may have a protective effect against the development of abnormal metabolic conditions. In addition, oxygen delivery systems may be of therapeutic value for supplying the tissue-specific oxygen requirements. Critical Issues: Precise in vivo methods to measure oxygenation are vital to disentangle some of the controversies related to this research area. Further, it is evident that there is a growing need for novel in vitro models to study the potential pathways involved in metabolic dysfunction to find appropriate therapeutic targets. Future Directions: Based on the existing evidence, it is suggested that oxygen availability has a key role in obesity and its related comorbidities. Oxygen should be considered in relation to potential therapeutic strategies in the treatment and prevention of metabolic disorders. Antioxid. Redox Signal. 35, 642-687.

Multi-functional cerium oxide nanoparticles regulate inflammation and enhance osteogenesis

Oxidative stress increases bone loss and limits repair, in part, through immunoregulation and the formation and maintenance of low-grade chronic inflammation. The aim of this study was to investigate the effect of cerium oxide nanoparticles (CeONPs) on (i) macrophage phenotype and cytokine expression under normal and simulated acute and chronic inflammatory conditions and, (ii) human mesenchymal stem cell (hBMSCs) proliferation, osteoinduction and osteogenic differentiation. Spherical particles composed of 60% Ce³⁺ with a hydrodynamic size of ~35 nm and surface charge of 25.4 mV were internalized within cells. Under both acute and chronic conditions, inducible nitric oxide synthase (iNOS) activity decreased with a significant reduction seen in the 1 and 10 μg/mL groups (p < 0.001). A dose dependent and significant increase in anti-inflammatory cytokine gene expression was observed in all CeONP groups under chronic inflammatory condition. No increase in alkaline phosphatase (ALP) activity or mineral deposits were measured following hBMSCs cultured without osteogenic media in any of the CeONP groups, however, a significant increase in osteogenic-related gene expression, ALP activity and bone mineral deposits was measured when supplemented with both CeONPs and osteogenic media. CeONP activity was multifaceted and exhibited low toxicity. A therapeutic dose of 1 μg/mL delivered a disparate but protective effect when under both acute and chronic inflammatory conditions while at the same dose, potentiated osteogenesis.

Synergistic Treatment of Obesity via Locally Promoting Beige Adipogenesis and Antioxidative Defense in Adipose Tissues

Obesity is a primary risk factor for type 2 diabetes, cardiovascular diseases, cancer, and other chronic diseases. Current antiobesity medications need frequent administration and show limited efficacy with severe side effects. Herein, browning agent rosiglitazone (Rsg) and antioxidant manganese tetroxide nanoparticles (MnNPs, around 250 nm) are integrated into electrospun short fibers (SF@Rsg-Mn) with a 1.5 μm width and a 20 μm length. Upon injection into inguinal adipose tissues, SF@Rsg-Mn are well retained in the local depots to sustainably release Rsg in 30 days for adipose tissue browning, while MnNPs on the fiber surface continuously scavenge adipose reactive oxygen species (ROS) for an extended period of time. Synergistic inhibition of fat accumulation through ROS scavenging and white adipocyte browning has been demonstrated for the first time, and the optimal synergistic ratio of Rsg and MnNPs is determined to be 1/14 via combination index examination. SF@Rsg-Mn inhibit lipid accumulation through downregulation of adipogenic gene PPARγ while promoting energy expenditure through upregulation of brown-specific gene UCP1 and mitochondrial function gene COX7A1. In a diet-induced obesity mouse model, a single injection of SF@Rsg-Mn into inguinal adipose tissues has accomplished a synergistic effect on body weight loss, fat reduction, glucose, and lipid metabolic improvement while minimizing adverse effects on other tissues, thereby paving the way to efficacious, safe, and practical treatment of obesity.

An overview on recent in vivo biological application of cerium oxide nanoparticles

Cerium oxide nanoparticles (CNPs) possess a great potential as therapeutic agents due to their ability to self-regenerate by reversibly switching between two valences +3 and +4. This article reviews recent articles dealing with in vivo studies of CNPs towards Alzheimer's disease, obesity, liver inflammation, cancer, sepsis, amyotrophic lateral sclerosis, acute kidney injury, radiation-induced tissue damage, hepatic ischemia reperfusion injury, retinal diseases and constipation. In vivo anti-cancer studies revealed the effectiveness of CNPs to reduce tumor growth and angiogenesis in melanoma, ovarian, breast and retinoblastoma cancer cell-induced mice, with their conjugation with folic acid, doxorubicin, CPM, or CXC receptor-4 antagonist ligand eliciting higher efficiency. After conjugation with triphenylphosphonium or magnetite nanoparticles, CNPs were shown to combat Alzheimer's disease by reducing amyloid-β, glial fibrillary acidic protein, inflammatory and oxidative stress markers in mice. By improving muscle function and longevity, the citrate/EDTA-stabilized CNPs could ameliorate amyotrophic lateral sclerosis. Also, they could effectively reduce obesity in mice by scavenging ROS and reducing adipogenesis, triglyceride synthesis, GAPDH enzyme activity, leptin and insulin levels. In CCl4-induced rats, stress signaling pathways due to inflammatory cytokines, liver enzymes, oxidative and endoplasmic reticulum messengers could be attenuated by CNPs. Commercial CNPs showed protective effects on rats with hepatic ischemia reperfusion and peritonitis-induced hepatic/cardiac injuries by decreasing oxidative stress and hepatic/cardiac inflammation. The same CNPs could improve kidney function by diminishing renal superoxide, hyperglycemia and tubular damage in peritonitis-induced acute kidney injury in rats. Radiation-induced lung and testicular tissue damage could be alleviated in mice, with the former showing improvement in pulmonary distress and bronchoconstriction and the latter exhibiting restoration in spermatogenesis rate and spermatid/spermatocyte number. Through enhancement of gastrointestinal motility, the CNPs could alleviate constipation in both young and old rats. They could also protect rat from light-induced retinal damage by slowing down neurodegenerative process and microglial activation.

One-pot synthesis of cerium and praseodymium co-doped carbon quantum dots as enhanced antioxidant for hydroxyl radical scavenging

The antioxidant activity of ceria nanoparticles is tightly regulated by size distribution and heteroatom doping. Inspired by this rule, cerium and praseodymium codoped carbon quantum dots (Ce/Pr-CQDs) were synthesized through the one-pot hydrothermal carbonization method. Taking intrinsic advantage of CQDs, the resultant Ce/Pr-CQDs exhibited uniform and ultra-small morphology with an average size of 2.8 nm, which led to an increased proportion of Ce³⁺. In addition, the doping of Pr into Ce-CQDs improved the redox properties. As we expected, the Ce/Pr-CQDs possessed enhanced hydroxyl radical scavenging properties compared with the cerium-doped carbon quantum dots (Ce-CQDs). Furthermore, Ce/Pr-CQDs with favorable biocompatibility and negligible cytotoxicity are readily internalized into cytoplasm, decreasing the level of reactive oxygen species (ROS). Taken together, the resultant Ce/Pr-CQDs displayed great potential for applications relating to oxidative-stress-associated disease.

Nanomaterials for the theranostics of obesity

As a chronic and lifelong disease, obesity not only significant impairs health but also dramatically shortens life span (at least 10 years). Obesity requires a life-long effort for the successful treatment because a number of abnormalities would appear in the development of obesity. Nanomaterials possess large specific surface area, strong absorptivity, and high bioavailability, especially the good targeting properties and adjustable release rate, which would benefit the diagnosis and treatment of obesity and obesity-related metabolic diseases. Herein, we discussed the therapy and diagnosis of obesity and obesity-related metabolic diseases by using nanomaterials. Therapies of obesity with nanomaterials include improving intestinal health and reducing energy intake, targeting and treating functional cell abnormalities, regulating redox homeostasis, and removing free lipoprotein in blood. Diagnosis of obesity-related metabolic diseases would benefit the therapy of these diseases. The development of nanomaterials will promote the diagnosis and therapy of obesity and obesity-related metabolic diseases.

Facile synthesis of cerium-doped carbon quantum dots as a highly efficient antioxidant for free radical scavenging

Excessive reactive oxygen species (ROS) can lead to irreversible damage to the human body in vivo, therefore it is highly desirable to exploit an efficient antioxidant. Recently, cerium oxide nanoparticles have attracted extensive attention in the field of biomedicine due to their excellent antioxidant properties. In this study, cerium-doped carbon quantum dots (Ce-doped CQDs) with hydroxyl radical scavenging capacity were synthesized for first time by one-step hydrothermal carbonization method. The resultant Ce-doped CQDs with the average particle size of 2.5 nm possessed the properties of good water solubility, colloid stability, and strong fluorescence, which are similar to traditional CQDs. Meanwhile, the Ce-doped CQDs had good biocompatibility and negligible cytotoxicity. Taking advantage of inherent ultra-small size, the Ce-doped CQDs exhibited a high Ce³⁺/Ce⁴⁺ ratio at the surface of particles. The radical scavenging capability of the Ce-doped CQDs was proved by a simple photometric system in vitro, which provided direct evidence for its antioxidant potency. Furthermore, the Ce-doped CQDs had a high ability to protect cells from hydrogen peroxide-induced damage by scavenging hydroxyl radicals. These results suggest that Ce-doped CQDs as a new ROS scavenger may provide potential prospects for the treatment of oxidative stress-related diseases.

Cerium Oxide Nanoparticles Regulate Insulin Sensitivity and Oxidative Markers in 3T3-L1 Adipocytes and C2C12 Myotubes

Insulin resistance is associated with oxidative stress, mitochondrial dysfunction, and a chronic low-grade inflammatory status. In this sense, cerium oxide nanoparticles (CeO₂ NPs) are promising nanomaterials with antioxidant and anti-inflammatory properties. Thus, we aimed to evaluate the effect of CeO₂ NPs in mouse 3T3-L1 adipocytes, RAW 264.7 macrophages, and C2C12 myotubes under control or proinflammatory conditions. Macrophages were treated with LPS, and both adipocytes and myotubes with conditioned medium (25% LPS-activated macrophages medium) to promote inflammation. CeO₂ NPs showed a mean size of ≤25.3 nm (96.7%) and a zeta potential of 30.57 ± 0.58 mV, suitable for cell internalization. CeO₂ NPs reduced extracellular reactive oxygen species (ROS) in adipocytes with inflammation while increased in myotubes with control medium. The CeO₂ NPs increased mitochondrial content was observed in adipocytes under proinflammatory conditions. Furthermore, the expression of Adipoq and Il10 increased in adipocytes treated with CeO₂ NPs. In myotubes, both Il1b and Adipoq were downregulated while Irs1 was upregulated. Overall, our results suggest that CeO₂ NPs could potentially have an insulin-sensitizing effect specifically on adipose tissue and skeletal muscle. However, further research is needed to confirm these findings.

Silver nanoparticles inhibit beige fat function and promote adiposity

Objective

Obesity is a complex chronic disease of high prevalence worldwide. Multiple factors play integral roles in obesity development, with rising interest focusing on the contribution of environmental pollutants frequent in modern society. Silver nanoparticles (AgNPs) are widely used for bactericidal purpose in various applications in daily life. However, their potential toxicity and contribution to the obesity epidemic are not clear.

Methods

Beige adipocytes are newly discovered adipocytes characterized by high thermogenic and energy dissipating capacity upon activation and the “browning” process. In the present study, we assess the impact of AgNPs exposure on beige adipocytes differentiation and functionality both in vitro and in vivo. We also systematically investigate the influence of AgNPs on adiposity and metabolic performance in mice, as well as the possible underlying molecular mechanism.

Results

The results showed that, independent of particle size, AgNPs inhibit the adipogenic, mitochondrial, and thermogenic gene programs of beige adipocytes, thus suppressing their differentiation ability, mitochondrial activity, and thermogenic response. Importantly, exposure to AgNPs in mice suppresses browning gene programs in subcutaneous fat, leading to decreased energy expenditure and increased adiposity in mice. Mechanistically, we found that AgNPs increase reactive oxidative species (ROS) levels and specifically activate MAPK-ERK signaling in beige adipocytes. The negative impacts of AgNPs on beige adipocytes can be ameliorated by antioxidant or ERK inhibitor FR180204 treatment.

Conclusions

Taken together, these results revealed an unexpected role of AgNPs in promoting adiposity through the inhibition of beige adipocyte differentiation and functionality, possibly by disrupting ROS homeostasis and ERK phosphorylation. Future assessments on the health risk of AgNPs applications and their safe dosages are warranted.

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The environmental pollutant AgNPs promote adiposity and metabolic disorders in mice.

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AgNPs suppress beige adipocytes differentiation and functionality both in vitro and in vivo.

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AgNPs increase ROS levels and specifically activate ERK signaling in beige adipocytes.

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The negative impacts of AgNPs can be ameliorated by antioxidant or ERK inhibitor.

The Impact of Metallic Nanoparticles on Stem Cell Proliferation and Differentiation

Nanotechnology has a wide range of medical and industrial applications. The impact of metallic nanoparticles (NPs) on the proliferation and differentiation of normal, cancer, and stem cells is well-studied. The preparation of NPs, along with their physicochemical properties, is related to their biological function. Interestingly, various mechanisms are implicated in metallic NP-induced cellular proliferation and differentiation, such as modulation of signaling pathways, generation of reactive oxygen species, and regulation of various transcription factors. In this review, we will shed light on the biomedical application of metallic NPs and the interaction between NPs and the cellular components. The in vitro and in vivo influence of metallic NPs on stem cell differentiation and proliferation, as well as the mechanisms behind potential toxicity, will be explored. A better understanding of the limitations related to the application of metallic NPs on stem cell proliferation and differentiation will afford clues for optimal design and preparation of metallic NPs for the modulation of stem cell functions and for clinical application in regenerative medicine.

Quantitative Proteomics Study Reveals Changes in the Molecular Landscape of Human Embryonic Stem Cells with Impaired Stem Cell Differentiation upon Exposure to Titanium Dioxide Nanoparticles

The increasing number of nanoparticles (NPs) being used in various industries has led to growing concerns of potential hazards that NP exposure can incur on human health. However, its global effects on humans and the underlying mechanisms are not systemically studied. Human embryonic stem cells (hESCs), with the ability to differentiate to any cell types, provide a unique system to assess cellular, developmental, and functional toxicity in vitro within a single system highly relevant to human physiology. Here, the quantitative proteomics approach is adopted to evaluate the molecular consequences of titanium dioxide NPs (TiO₂ NPs) exposure in hESCs. The study identifies ≈328 unique proteins significantly affected by TiO₂ NPs exposure. Proteomics analysis highlights that TiO₂ NPs can induce DNA damage, elevated oxidative stress, apoptotic responses, and cellular differentiation. Furthermore, in vivo analysis demonstrates remarkable reduction in the ability of hESCs in teratoma formation after TiO₂ NPs exposure, suggesting impaired pluripotency. Subsequently, it is found that TiO₂ NPs can disrupt hESC mesoderm differentiation into cardiomyocytes. The study unveils comprehensive changes in the molecular landscape of hESCs by TiO₂ NPs and identifies the impact which TiO₂ NPs can have on the pluripotency and differentiation properties of human stem cells.

Recent review of the effect of nanomaterials on stem cells

The field of stem-cell-therapy offers considerable promise as a means of delivering new treatments for a wide range of diseases. Recent progress in nanotechnology has stimulated the development of multifunctional nanomaterials (NMs) for stem-cell-therapy. Several clinical trials based on the use of NMs are currently underway for stem-cell-therapy purposes, such as drug/gene delivery and imaging. However, the interactions between NMs and stem cells are far from being completed, and the effects of the NMs on cellular behavior need critical evaluation. In this review, the interactions between several types of mostly used NMs and stem cells, and their associated possible mechanisms are systematically discussed, with specific emphasis on the possible differentiation effects induced by NMs. It is expected that the enhanced understanding of NM-stem cell interactions will facilitate biomaterial design for stem-cell-therapy and regenerative medicine applications.

Biomineralization-Inspired Synthesis of Cerium-Doped Carbonaceous Nanoparticles for Highly Hydroxyl Radical Scavenging Activity

Cerium oxide nanoparticles recently have received extensive attention in biomedical applications due to their excellent anti-oxidation performance. In this study, a simple, mild, and green approach was developed to synthesize cerium-doped carbonaceous nanoparticles (Ce-doped CNPs) using bio-mineralization of bull serum albumin (BSA) as precursor. The resultant Ce-doped CNPs exhibited uniform and ultrasmall morphology with an average size of 14.7 nm. XPS and FTIR results revealed the presence of hydrophilic group on the surface of Ce-doped CNPs, which resulted in excellent dispersity in water. The CCK-8 assay demonstrated that Ce-doped CNPs possessed favorable biocompatibility and negligible cytotoxicity. Using H₂O₂-induced reactive oxygen species (ROS) as model, Ce-doped CNPs showed highly hydroxyl radical scavenging capability. Furthermore, flow cytometry and live-dead staining results indicated that Ce-doped CNPs protected cells from H₂O₂-induced damage in a dose-dependent effect, which provided a direct evidence for anti-oxidative performance. These findings suggest that Ce-doped CNPs as novel ROS scavengers may provide a potential therapeutic prospect in treating diseases associated with oxidative stress.

Artificial cerium-based proenzymes confined in lyotropic liquid crystals: synthetic strategy and on-demand activation

The artificial proenzyme concept for ultra-small cerium-based nanoparticles: the on-demand activation of inactive nanoparticles to mimic the activity of superoxide dismutase.

Smart Materials Meet Multifunctional Biomedical Devices: Current and Prospective Implications for Nanomedicine

With the increasing advances in the fabrication and in monitoring approaches of nanotechnology devices, novel materials are being synthesized and tested for the interaction with biological environments. Among them, smart materials in particular provide versatile and dynamically tunable platforms for the investigation and manipulation of several biological activities with very low invasiveness in hardly accessible anatomical districts. In the following, we will briefly recall recent examples of nanotechnology-based materials that can be remotely activated and controlled through different sources of energy, such as electromagnetic fields or ultrasounds, for their relevance to both basic science investigations and translational nanomedicine. Moreover, we will introduce some examples of hybrid materials showing mutually beneficial components for the development of multifunctional devices, able to simultaneously perform duties like imaging, tissue targeting, drug delivery, and redox state control. Finally, we will highlight challenging perspectives for the development of theranostic agents (merging diagnostic and therapeutic functionalities), underlining open questions for these smart nanotechnology-based devices to be made readily available to the patients in need.

Cerium oxide nanoparticles inhibit differentiation of neural stem cells

Cerium oxide nanoparticles (nanoceria) display antioxidant properties and have shown cytoprotective effects both in vitro and in vivo. Here, we explored the effects of nanoceria on neural progenitor cells using the C17.2 murine cell line as a model. First, we assessed the effects of nanoceria versus samarium (Sm) doped nanoceria on cell viability in the presence of the prooxidant, DMNQ. Both particles were taken up by cells and nanoceria, but not Sm-doped nanoceria, elicited a temporary cytoprotective effect upon exposure to DMNQ. Next, we employed RNA sequencing to explore the transcriptional responses induced by nanoceria or Sm-doped nanoceria during neuronal differentiation. Detailed computational analyses showed that nanoceria altered pathways and networks relevant for neuronal development, leading us to hypothesize that nanoceria inhibits neuronal differentiation, and that nanoceria and Sm-doped nanoceria both interfere with cytoskeletal organization. We confirmed that nanoceria reduced neuron specific β3-tubulin expression, a marker of neuronal differentiation, and GFAP, a neuroglial marker. Furthermore, using super-resolution microscopy approaches, we could show that both particles interfered with cytoskeletal organization and altered the structure of neural growth cones. Taken together, these results reveal that nanoceria may impact on neuronal differentiation, suggesting that nanoceria could pose a developmental neurotoxicity hazard.

The negative effect of silica nanoparticles on adipogenic differentiation of human mesenchymal stem cells

Nanoparticles have drawn much attention for a wide variety of applications in biomedical and bioengineering fields. The combined use of nanoparticles and human mesenchymal stem cells (hMSCs) in tissue engineering and regenerative medicine requires more knowledge of the influence of nanoparticles on cell viability and differentiation potential of hMSCs. The objective of this study is to investigate the in vitro uptake of silica nanoparticles (silica NPs) and their effect on adipogenic differentiation of hMSCs. After exposure of hMSCs to silica NPs, the uptake and localization of silica NPs were assessed using transmission electron microscopy (TEM) and confocal laser scanning microscopy (CLSM). The adipogenic differentiation potential of hMSCs was examined by analyzing the formation and accumulation of lipids droplets, triglyceride (TG) content and the expression of adipogenic marker genes/proteins. The results showed that silica NPs did not affect the cell viability but significantly decreased the differentiation of hMSCs to adipocytes. These findings improve the understanding of the influence of silica NPs on adipogenic differentiation of hMSCs and will provide a reference for the applications of silica NPs in biomedical and bioengineering fields.

Cell-based cytotoxicity assays for engineered nanomaterials safety screening: exposure of adipose derived stromal cells to titanium dioxide nanoparticles

BACKGROUND

Increasing production of nanomaterials requires fast and proper assessment of its potential toxicity. Therefore, there is a need to develop new assays that can be performed in vitro, be cost effective, and allow faster screening of engineered nanomaterials (ENMs).

RESULTS

Herein, we report that titanium dioxide (TiO2) nanoparticles (NPs) can induce damage to adipose derived stromal cells (ADSCs) at concentrations which are rated as safe by standard assays such as measuring proliferation, reactive oxygen species (ROS), and lactate dehydrogenase (LDH) levels. Specifically, we demonstrated that low concentrations of TiO2 NPs, at which cellular LDH, ROS, or proliferation profiles were not affected, induced changes in the ADSCs secretory function and differentiation capability. These two functions are essential for ADSCs in wound healing, energy expenditure, and metabolism with serious health implications in vivo.

CONCLUSIONS

We demonstrated that cytotoxicity assays based on specialized cell functions exhibit greater sensitivity and reveal damage induced by ENMs that was not otherwise detected by traditional ROS, LDH, and proliferation assays. For proper toxicological assessment of ENMs standard ROS, LDH, and proliferation assays should be combined with assays that investigate cellular functions relevant to the specific cell type.

Remote Control of Cellular Functions: The Role of Smart Nanomaterials in the Medicine of the Future

The remote control of cellular functions through smart nanomaterials represents a biomanipulation approach with unprecedented potential applications in many fields of medicine, ranging from cancer therapy to tissue engineering. By actively responding to external stimuli, smart nanomaterials act as real nanotransducers able to mediate and/or convert different forms of energy into both physical and chemical cues, fostering specific cell behaviors. This report describes those classes of nanomaterials that have mostly paved the way to a "wireless" control of biological phenomena, focusing the discussion on some examples close to the clinical practice. In particular, magnetic fields, light irradiation, ultrasound, and pH will be presented as means to manipulate the cellular fate, due to the peculiar physical/chemical properties of some smart nanoparticles, thus providing realistic examples of "nanorobots" approaching the visionary ideas of Richard Feynman.

Protective effects of cerium oxide and yttrium oxide nanoparticles on reduction of oxidative stress induced by sub-acute exposure to diazinon in the rat pancreas

Diazinon is a kind of organophosphorus (OP) compound that is broadly used against different species of insects and pests. Oxidative stress can occur at very early stages of diazinon exposure and the pancreas is one of the main target organs for toxicity by diazinon. The aim of this study was to evaluate the protective effects of cerium oxide nanoparticles (CeO₂ NPs) and yttrium oxide nanoparticles (Y₂O₃ NPs) against the pancreatic damage from sub-acute exposure of diazinon. Diazinon at a dose of 70mg/kg/day was given through gavage to rats once a day. Along with diazinon, trace amounts of CeO₂ NPs and Y₂O₃ NPs (35mg/kg and 45mg/kg per day, respectively) were administered by intraperitoneal injection once a day for 2 weeks. Animals weight and blood glucose were measured during the treatment, and oxidative stress biomarkers, diabetes physiology, function and viability of cells were investigated at the end of the treatment in serum and pancreas tissues. Apoptosis of islets was examined by the flow cytometry. The high blood glucose level and significant weight loss resulting from diazinon were modified as a result of the application of the NPs. A significant recovery in oxidative stress markers, pro-insulin, insulin, C-peptide, adenosine diphosphate/adenosine triphosphate (ATP/ADP) ratio, caspase-3 and -9 activities and apoptosis-necrosis in the islets was observed. In conclusion, administration of CeO₂ NPs or Y₂O₃ NPs only or their combination with suitable and defined dose will help to overcome the consequences from oxidant agents.

The Role of Reactive Oxygen Species (ROS) in the Biological Activities of Metallic Nanoparticles

Nanoparticles (NPs) possess unique physical and chemical properties that make them appropriate for various applications. The structural alteration of metallic NPs leads to different biological functions, specifically resulting in different potentials for the generation of reactive oxygen species (ROS). The amount of ROS produced by metallic NPs correlates with particle size, shape, surface area, and chemistry. ROS possess multiple functions in cellular biology, with ROS generation a key factor in metallic NP-induced toxicity, as well as modulation of cellular signaling involved in cell death, proliferation, and differentiation. In this review, we briefly explained NP classes and their biomedical applications and describe the sources and roles of ROS in NP-related biological functions in vitro and in vivo. Furthermore, we also described the roles of metal NP-induced ROS generation in stem cell biology. Although the roles of ROS in metallic NP-related biological functions requires further investigation, modulation and characterization of metallic NP-induced ROS production are promising in the application of metallic NPs in the areas of regenerative medicine and medical devices.

Silica nanoparticles inhibit brown adipocyte differentiation via regulation of p38 phosphorylation

Nanoparticles are of great interest due to their wide variety of biomedical and bioengineering applications. However, they affect cellular differentiation and/or intracellular signaling when applied and exposed to target organisms or cells. The brown adipocyte is a cell type important in energy homeostasis and thus closely related to obesity. In this study, we assessed the effects of silica nanoparticles (SNPs) on brown adipocyte differentiation. The results clearly showed that brown adipocyte differentiation was significantly repressed by exposure to SNPs. The brown adipocyte-specific genes as well as mitochondrial content were also markedly reduced. Additionally, SNPs led to suppressed p38 phosphorylation during brown adipocyte differentiation. These effects depend on the size of SNPs. Taken together, these results lead us to suggest that SNP has anti-brown adipogenic effect in a size-dependent manner via regulation of p38 phosphorylation.

Enhancement of radiotherapy by ceria nanoparticles modified with neogambogic acid in breast cancer cells

Radiotherapy is one of the main strategies for cancer treatment but has significant challenges, such as cancer cell resistance and radiation damage to normal tissue. Radiosensitizers that selectively increase the susceptibility of cancer cells to radiation can enhance the effectiveness of radiotherapy. We report here the development of a novel radiosensitizer consisting of monodispersed ceria nanoparticles (CNPs) covered with the anticancer drug neogambogic acid (NGA-CNPs). These were used in conjunction with radiation in MCF-7 breast cancer cells, and the efficacy and mechanisms of action of this combined treatment approach were evaluated. NGA-CNPs potentiated the toxic effects of radiation, leading to a higher rate of cell death than either treatment used alone and inducing the activation of autophagy and cell cycle arrest at the G2/M phase, while pretreatment with NGA or CNPs did not improve the rate of radiation-induced cancer cells death. However, NGA-CNPs decreased both endogenous and radiation-induced reactive oxygen species formation, unlike other nanomaterials. These results suggest that the adjunctive use of NGA-CNPs can increase the effectiveness of radiotherapy in breast cancer treatment by lowering the radiation doses required to kill cancer cells and thereby minimizing collateral damage to healthy adjacent tissue.