Fullerol antagonizes dexamethasone-induced oxidative stress and adipogenesis while enhancing osteogenesis in a cloned bone marrow mesenchymal stem cell

Catalpol ameliorates dexamethasone-induced osteoporosis by promoting osteogenic differentiation of bone marrow mesenchymal stem cells via the activation of PKD1 promoter

OBJECTIVE

To investigate the effects of CA on glucocorticoid-induced osteoporosis (GIOP) and lucubrate the underlying mechanism of CA via the activation of polycystic kidney disease-1(PKD1) in bone marrow mesenchymal stem cells (BMSCs).

METHODS

In vivo, a GIOP model in mice treated with dexamethasone (Dex) was established. Biomechanical, micro-CT, immunofluorescence staining of OCN, ALP and PKD1 and others were severally determined. qRT-PCR and Western blot methods were adopted to elucidate the particular mechanisms of CA on GIOP. In addition, BMSCs cultured in vitro were also induced by Dex to verify the effects of CA. Finally, siRNA and luciferase activity assays were performed to confirm the mechanisms.

RESULTS

We found that CA could restore the destroyed bone microarchitecture and increase the bone mass in GIOP mice. CA could also upregulate PKD1 protein expression, reduce oxidative stress, and promote mRNA expression of bone formation-associated markers in GIOP mice. Furthermore, it was also observed that CA reduced oxidative stress and promoted osteogenic differentiation in Dex-induced BMSCs. Mechanically, CA could promote protein expression via increasing the activity of PKD1 promoter.

CONCLUSION

This study provides important evidences for CA in the further clinical treatment of GIOP, reveals the activation of PKD1 promoter as the underlying mechanism.

Carbon Nanomaterial-Based Hydrogels as Scaffolds in Tissue Engineering: A Comprehensive Review

Carbon-based nanomaterials (CBNs) are a category of nanomaterials with various systems based on combinations of sp2 and sp3 hybridized carbon bonds, morphologies, and functional groups. CBNs can exhibit distinguished properties such as high mechanical strength, chemical stability, high electrical conductivity, and biocompatibility. These desirable physicochemical properties have triggered their uses in many fields, including biomedical applications. In this review, we specifically focus on applying CBNs as scaffolds in tissue engineering, a therapeutic approach whereby CBNs can act for the regeneration or replacement of damaged tissue. Here, an overview of the structures and properties of different CBNs will first be provided. We will then discuss state-of-the-art advancements of CBNs and hydrogels as scaffolds for regenerating various types of human tissues. Finally, a perspective of future potentials and challenges in this field will be presented. Since this is a very rapidly growing field, we expect that this review will promote interdisciplinary efforts in developing effective tissue regeneration scaffolds for clinical applications.

Nanotechnology enabled radioprotectants to reduce space radiation-induced reactive oxidative species

Interest in space exploration has seen substantial growth following recent launch and operation of modern space technologies. In particular, the possibility of travel beyond low earth orbit is seeing sustained support. However, future deep space travel requires addressing health concerns for crews under continuous, longer-term exposure to adverse environmental conditions. Among these challenges, radiation-induced health issues are a major concern. Their potential to induce chronic illness is further potentiated by the microgravity environment. While investigations into the physiological effects of space radiation are still under investigation, studies on model ionizing radiation conditions, in earth and micro-gravity conditions, can provide needed insight into relevant processes. Substantial formation of high, sustained reactive oxygen species (ROS) evolution during radiation exposure is a clear threat to physiological health of space travelers, producing indirect damage to various cell structures and requiring therapeutic address. Radioprotection toward the skeletal system components is essential to astronaut health, due to the high radio-absorption cross-section of bone mineral and local hematopoiesis. Nanotechnology can potentially function as radioprotectant and radiomitigating agents toward ROS and direct radiation damage. Nanoparticle compositions such as gold, silver, platinum, carbon-based materials, silica, transition metal dichalcogenides, and ceria have all shown potential as viable radioprotectants to mitigate space radiation effects with nanoceria further showing the ability to protect genetic material from oxidative damage in several studies. As research into space radiation-induced health problems develops, this review intends to provide insights into the nanomaterial design to ameliorate pathological effects from ionizing radiation exposure. This article is categorized under: Therapeutic Approaches and Drug Discovery > Emerging Technologies Nanotechnology Approaches to Biology > Nanoscale Systems in Biology Nanotechnology Approaches to Biology > Cells at the Nanoscale Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease.

Incorporating the Antioxidant Fullerenol into Calcium Phosphate Bone Cements Increases Cellular Osteogenesis without Compromising Physical Cement Characteristics

Herein, fullerenol (Ful), a highly water-soluble derivative of C60 fullerene with demonstrated antioxidant activity, is incorporated into calcium phosphate cements (CPCs) to enhance their osteogenic ability. CPCs with added carboxymethyl cellulose/gelatin (CMC/Gel) are doped with biocompatible Ful particles at concentrations of 0.02, 0.04, and 0.1 wt v%-1 and evaluated for Ful-mediated mechanical performance, antioxidant activity, and in vitro cellular osteogenesis. CMC/gel cements with the highest Ful concentration decrease setting times due to increased hydrogen bonding from Ful's hydroxyl groups. In vitro studies of reactive oxygen species (ROS) scavenging with CMC/gel cements demonstrate potent antioxidant activity with Ful incorporation and cement scavenging capacity is highest for 0.02 and 0.04 wt v%-1 Ful. In vitro cytotoxicity studies reveal that 0.02 and 0.04 wt v%-1 Ful cements also protect cellular viability. Finally, increase of alkaline phosphatase (ALP) activity and expression of runt-related transcription factor 2 (Runx2) in MC3T3-E1 pre-osteoblast cells treated with low-dose Ful cements demonstrate Ful-mediated osteogenic differentiation. These results strongly indicate that the osteogenic abilities of Ful-loaded cements are correlated with their antioxidant activity levels. Overall, this study demonstrates exciting potential of Fullerenol as an antioxidant and proosteogenic additive for improving the performance of calcium phosphate cements in bone reconstruction procedures.

Enhancers of mesenchymal stem cell stemness and therapeutic potency

Mesenchymal stem cells (MSCs) are multipotent stromal cells that can differentiate into a range of cell types, including osteoblasts, chondrocytes, myocytes, and adipocytes. Multiple preclinical investigations and clinical trials employed enhanced MSCs-dependent therapies in treatment of inflammatory and degenerative diseases. They have demonstrated considerable and prospective therapeutic potentials even though the large-scale use remains a problem. Several strategies have been used to improve the therapeutic potency of MSCs in cellular therapy. Treatment of MSCs utilizing pharmaceutical compounds, cytokines, growth factors, hormones, and vitamins have shown potential outcomes in boosting MSCs' stemness. In this study, we reviewed the current advances in enhancing techniques that attempt to promote MSCs' therapeutic effectiveness in cellular therapy and stemness in vivo with potential mechanisms and applications.

Antioxidant and antiviral activity of fullerol against Zika virus

Neglected for years, Zika virus (ZIKV) has become one of the most relevant arboviruses in current public health. The recent Zika fever epidemic in the Americas generated a worldwide alert due to the association with diseases such as Guillain-Barré syndrome and congenital syndromes. Among the pathogenesis of ZIKV, recent studies suggest that oxidative stress plays an important role during infection and that compounds capable of modulating oxidative stress are promising as therapeutics. Furthermore, so far there are no specific and efficient antiviral drug or vaccine available against ZIKV. Thus, fullerol was evaluated in the context of infection by ZIKV, since it is a carbon nanomaterial known for its potent antioxidant action. In this study, fullerol did not alter cell viability at the concentrations tested, proving to be inert, beyond to presenting high antioxidant power at low concentrations. ZIKV infection of human glioblastoma increased the production of reactive oxygen species by 60% and modulated the Nrf-2 pathway activity negatively. After treatment with fullerol, both conditions were restored to baseline levels. Additionally, fullerol was able to reduce viral production by up to 90%. Therefore, our results suggest that fullerol as a promising candidate in the control of ZIKV infections, presenting both antioxidant and antiviral action.

Adverse Effects of Oxidative Stress on Bone and Vasculature in Corticosteroid-Associated Osteonecrosis: Potential Role of Nuclear Factor Erythroid 2-Related Factor 2 in Cytoprotection

Significance: Osteonecrosis (ON) is characterized by bone tissue death due to disturbance of the nutrient artery. The detailed process leading to the necrotic changes has not been fully elucidated. Clinically, high-dose corticosteroid therapy is one of the main culprits behind osteonecrosis of the femoral head (ONFH). Recent Advances: Numerous studies have proposed that such ischemia concerns various intravascular mechanisms. Of all reported risk factors, the involvement of oxidative stress in the irreversible damage suffered by bone-related and vascular endothelial cells during ischemia simply cannot be overlooked. Several articles also have sought to elucidate oxidative stress in relation to ON using animal models or in vitro cell cultures. Critical Issues: However, as far as we know, antioxidant monotherapy has still not succeeded in preventing ONFH in humans. To provide this desideratum, we herein summarize the current knowledge about the influence of oxidative stress on ON, together with data about the preventive effects of administering antioxidants in corticosteroid-induced ON animal models. Moreover, oxidative stress is counteracted by nuclear factor erythroid 2-related factor 2 (Nrf2)-dependent cytoprotective network through regulating antioxidant expressions. Therefore, we also describe Nrf2 regulation and highlight its role in the pathology of ON. Future Directions: This is a review of all available literature to date aimed at developing a deeper understanding of the pathological mechanism behind ON from the perspective of oxidative stress. It may be hoped that this synthesis will spark the development of a prophylactic strategy to benefit corticosteroid-associated ONFH patients. Antioxid. Redox Signal. 35, 357-376.

Ameliorative impacts of Allium cepa Linnaeus aqueous extract against testicular damage induced by dexamethasone

The present study aimed to explore the impact of onion (Allium cepa Linnaeus) extract on testicular damage induced by dexamethasone. Forty male Wistar rats were divided into four groups (control, dexamethasone, onion extract and dexamethasone group treated with onion extract). Testosterone levels, antioxidant parameters and the expression of caspase-3 and IL-1β, IL-12, IL-10 genes, as well as histopathological examination and immunohistochemical studies of Bcl2 and caspase-9 expression, were examined. Dexamethasone was found to decrease GSH, total antioxidant activity and testosterone levels, meanwhile treatment with onion extract normalised these levels. MDA was increased in dexamethasone group but appeared normal in the treated group. Dexamethasone was shown to downregulate IL-10 and IL-2 gene expression. Conversely, IL-1β and caspase-3 gene expression were upregulated by dexamethasone and normalised in the treated group. Histopathological analysis found that dexamethasone caused atrophy to the seminiferous tubules and degeneration to spermatocytes, and immunohistochemical analysis showed overexpression of caspase-9 and inhibited the expression of Bcl-2 in dexamethasone group. These effects were normalised in the onion extract treated group. In conclusion, onion extract have a preventative effect against dexamethasone-induced testicular damage in rats; therefore, its use in complementary therapy is recommended.

Carbonaceous Nanomaterials-Mediated Defense Against Oxidative Stress

The concept of nanoscale materials and their applications in industrial technologies, consumer goods, as well as in novel medical therapies has rapidly escalated in the last several years. Consequently, there is a critical need to understand the mechanisms that drive nanomaterials biocompatibility or toxicity to human cells and tissues. The ability of nanomaterials to initiate cellular pathways resulting in oxidative stress has emerged as a leading hypothesis in nanotoxicology. Nevertheless, there are a few examples revealing another face of nanomaterials - they can alleviate oxidative stress via decreasing the level of reactive oxygen species. The fundamental structural and physicochemical properties of carbonaceous nanomaterials that govern these anti-oxidative effects are discussed in this article. The signaling pathways influenced by these unique nanomaterials, as well as examples of their applications in the biomedical field, e.g. cell culture, cell-based therapies or drug delivery, are presented. We anticipate this emerging knowledge of intrinsic anti-oxidative properties of carbon nanomaterials to facilitate the use of tailored nanoparticles in vivo.

Bromosulfophthalein suppresses inflammatory effects in lipopolysaccharide-stimulated RAW264.7 macrophages

OBJECTIVE

It has been reported that glutathione (GSH), the most abundant cellular antioxidant, can inhibit production of pro-inflammatory cytokines by activated macrophages. Bromosulfophthalein (BSP) has been recognized as an inhibitor of the efflux of reduced GSH from cells, leading to an increase in the intracellular GSH level. In this study, we evaluated, for the first time, whether BSP possessed anti-inflammatory effects in lipopolysaccharide (LPS)-stimulated macrophages.

MATERIALS AND METHODS

RAW 264.7 cells were treated with BSP and the levels of proinflammatory cytokines, GSH, and nitrite were assessed. Gene expression of inducible nitric oxide synthase (iNOS), tumor necrosis factor alpha (TNF α), interleukin-1beta (IL-1β), and interleukin-6 (IL-6) was analyzed via quantitative RT-PCR. We also examined various inflammatory signaling pathways including Akt/forkhead box protein O1 (FoxO1)/toll-like receptor 4 (TLR4), mitogen-activated protein kinases (MAPKs), and Fas protein by Western blot and flow cytometry analysis.

RESULTS

Our study demonstrated that BSP induced an increase in intracellular GSH level in LPS-stimulated macrophages. BSP inhibited production of nitric oxide and proinflammatory cytokines. BSP increased phosphorylation of Akt and nuclear exclusion of FoxO1 and suppressed TLR4 expression. Additionally, BSP decreased MAPKs activation and Fas expression.

DISCUSSION AND CONCLUSION

Taken together, these data suggest that BSP can attenuate inflammation through multiple signaling pathways. These findings highlight the potential of BSP as a new anti-inflammatory agent.

Cytoprotective effects of antioxidant supplementation on mesenchymal stem cell therapy

Mesenchymal stem cells (MSCs) are earmarked as perfect candidates for cell therapy and tissue engineering due to their capacity to differentiate into different cell types. However, their potential for application in regenerative medicine declines when the levels of the reactive oxygen and nitrogen species (RONS) increase from the physiological levels, a phenomenon which is at least inevitable in ex vivo cultures and air-exposed damaged tissues. Increased levels of RONS can alter the patterns of osteogenic and adipogenic differentiation and inhibit proliferation, as well. Besides, oxidative stress enhances senescence and cell death, thus lowering the success rates of the MSC engraftment. Hence, in this review, we have selected some representatives of antioxidants and newly emerged nano antioxidants in three main categories, including chemical compounds, biometabolites, and protein precursors/proteins, which are proved to be effective in the treatment of MSCs. We will focus on how antioxidants can be applied to optimize the clinical usage of the MSCs and their associated signaling pathways. We have also reviewed several paralleled properties of some antioxidants and nano antioxidants which can be simultaneously used in real-time imaging, scaffolding techniques, and other applications in addition to their primary antioxidative function.

New strategy of bone marrow mesenchymal stem cells against oxidative stress injury via Nrf2 pathway: oxidative stress preconditioning

Clinically, bone marrow mesenchymal stem cells (BMSCs) have been used in treatment of many diseases, but the local oxidative stress (OS) of lesion severely limits the survival of BMSCs, which reduces the efficacy of BMSCs transplantation. Therefore, enhancing the anti‐OS stress ability of BMSCs is a key breakthrough point. Preconditioning is a common protective mechanism for cells or body. Here, the aim of this study was to investigate the effects of OS preconditioning on the anti‐OS ability of BMSCs and its mechanism. Fortunately, OS preconditioning can increase the expression of superoxide dismutase, catalase, NQO1, and heme oxygenase 1 through the nuclear factor erythroid 2‐related factor 2 pathway, thereby decreased the intracellular reactive oxygen species (ROS) levels, relieved the damage of ROS to mitochondria, DNA and cell membrane, enhanced the anti‐OS ability of BMSCs, and promoted the survival of BMSCs under OS.

Antioxidative nanofullerol inhibits macrophage activation and development of osteoarthritis in rats

Background: There is emerging evidence which suggests that cellular ROS including nitric oxide (NO) are important mediators for inflammation and osteoarthritis (OA). Water-soluble polyhydroxylated fullerene C60 (fullerol) nanoparticle has been demonstrated to have an outstanding ability to scavenge ROS.

Purpose: The objective of this study is to assess the effects of fullerol on inflammation and OA by in vitro and in vivo studies.

Methods: For in vitro experiments, primary mouse peritoneal macrophages and a macrophage cell line RAW264.7 were stimulated to inflammatory phenotypes by lipopolysaccharide (LPS) in the presence of fullerol. For the animal study, OA model was created by intra-articular injection of monoiodoacetate into the knee joints of rats and fullerol was intravenously injected immediately after OA induction.

Results: NO production and pro-inflammatory gene expression induced by LPS was significantly diminished by fullerol in both macrophage cell types. Meanwhile, fullerol could remarkably reduce phosphorylation of p38 mitogen-activated protein kinase, and protein level of transcription factors nuclear factor-kappaB and forkhead box transcription factor 1 within the nucleus. The animal study delineated that systematic administration of fullerol prevented OA, inhibiting inflammation of synovial membranes and the damage toward the cartilage chondrocytes in the OA joints.

Conclusion: Antioxidative fullerol may have a potential therapeutic application for OA.

Aggregation Behavior and Antioxidant Properties of Amphiphilic Fullerene C60 Derivatives Cofunctionalized with Cationic and Nonionic Hydrophilic Groups

Amphiphilic derivatives of fullerene C₆₀ are attractive from viewpoints of supramolecular chemistry and biomedicine. The establishment of relationships among the molecular structure, aggregation behavior and properties such as scavenging radicals of the amphiphilic C₆₀ derivatives is the key to push these carbon nanomaterials to real applications. In this work, six monosubstituted C₆₀ derivatives were synthesized by a one-step quaternization of their neutral precursors, which bear Percec monodendrons terminated with oligo(poly(ethylene oxide)) (o-PEO) chain(s). The main difference among the C₆₀ derivatives lies in the number and substituted position of the o-PEO chain(s) within the Percec monodendron. Derivative with a 4-substitution of the o-PEO chain still showed limited solubility in water. Other derivatives possessing two or three o-PEO chains exhibited much improved solubilities and rich aggregation behavior in water. It was found that the formation of aggregates is regulated both by the number and the substituted pattern of the o-PEO chains. Typical morphologies include nanosheets, nanowires, vesicles, nanotubes, and nanorods. Although the structures of the C₆₀ derivatives are different from those of traditional surfactants, their aggregation behavior can be also well explained by applying the theory of critical packing parameter. Interestingly, the capabilities of the C₆₀ derivatives to scavenge the hydroxyl radicals (OH^·-) followed the same order of their solubility in water, where the compound bearing three o-PEO chains with a 2,3,4-substitution got the champion quenching efficiency of ∼97.79% at a concentration of 0.15 mg·mL^-1 (∼0.11 mmol·L^-1).

The Yin and Yang of carbon nanomaterials in atherosclerosis

With unique characteristics such as high surface area, capacity of various functionalization, low weight, high conductivity, thermal and chemical stability, and free radical scavenging, carbon nanomaterials (CNMs) such as carbon nanotubes (CNTs), fullerene, graphene (oxide), carbon nanohorns (CNHs), and their derivatives have increasingly been utilized in nanomedicine and biomedicine. On the one hand, owing to ever-increasing applications of CNMs in technological and industrial fields as well as presence of combustion-derived CNMs in the ambient air, the skepticism has risen over the adverse effects of CNMs on human being. The influences of CNMs on cardiovascular system and cardiovascular diseases (CVDs) such as atherosclerosis, of which consequences are ischemic heart disease and ischemic stroke, as the main causes of death, is of paramount importance. In this regard, several studies have been devoted to specify the biomedical applications and cardiovascular toxicity of CNMs. Therefore, the aim of this review is to specify the roles and applications of various CNMs in atherosclerosis, and also identify the key role playing parameters in cardiovascular toxicity of CNMs so as to be a clue for prospective deployment of CNMs.

Regulation of the mitochondrial reactive oxygen species: Strategies to control mesenchymal stem cell fates ex vivo and in vivo

Mesenchymal stem cells (MSCs) are broadly used in cell‐based regenerative medicine because of their self‐renewal and multilineage potencies in vitro and in vivo. To ensure sufficient amounts of MSCs for therapeutic purposes, cells are generally cultured in vitro for long‐term expansion or specific terminal differentiation until cell transplantation. Although physiologically up‐regulated reactive oxygen species (ROS) production is essential for maintenance of stem cell activities, abnormally high levels of ROS can harm MSCs both in vitro and in vivo. Overall, additional elucidation of the mechanisms by which physiological and pathological ROS are generated is necessary to better direct MSC fates and improve their therapeutic effects by controlling external ROS levels. In this review, we focus on the currently revealed ROS generation mechanisms and the regulatory routes for controlling their rates of proliferation, survival, senescence, apoptosis, and differentiation. A promising strategy in future regenerative medicine involves regulating ROS generation via various means to augment the therapeutic efficacy of MSCs, thus improving the prognosis of patients with terminal diseases.

Mangiferin inhibits apoptosis and oxidative stress via BMP2/Smad-1 signaling in dexamethasone-induced MC3T3-E1 cells

Mangiferin is a xanthone glucoside, which possesses antioxidant, antiviral, antitumor and anti-inflammatory functions, and is associated with gene regulation. However, it remains unknown whether mangiferin protects osteoblasts, such as the MC3T3-E1 cell line, against glucocorticoid-induced damage. In the present study, MC3T3-E1 cells were treated with dexamethasone (Dex), which is a well-known synthetic glucocorticoid, in order to establish a glucocorticoid-induced cell injury model. After Dex and/or mangiferin treatment, cell viability, apoptosis and reactive oxygen species (ROS) production was measured by Cell Counting kit-8 (CCK-8) and flow cytometry, respectively, and the concentration of tumor necrosis factor (TNF)-α, interleukin (IL)-6 and macrophage colony-stimulating factor (M-CSF) was measured by ELISA. The expression of bone morphogenetic protein 2 (BMP2), phosphorylated-SMAD family member 1 (p-Smad-1), t-Smad-1, osterix (OSX), osteocalcin (OCN), osteoprotegerin (OPG), receptor activator of nuclear factor-κB (RANK), RANK ligand (RANKL), B-cell lymphoma 2 (Bcl-2) and Bcl-2-associated X protein (Bax) was measured by real-time PCR and/or western blot analysis. The results indicated that pretreatment of MC3T3-E1 cells with mangiferin for 3 h prior to exposure to Dex for 48 h significantly attenuated Dex-induced injury and inflammation, as demonstrated by increased cell viability, and decreases in apoptosis, ROS generation, and the secretion of TNF-α, IL-6 and M-CSF. In addition, pretreatment with mangiferin markedly reduced Dex-induced BMP2 and p-Smad-1 downregulation, and corrected the expression of differentiation- and apoptosis-associated markers, including alkaline phosphatase, OSX, OCN, OPG, RANK, RANKL, Bcl-2 and Bax, which were altered by Dex treatment. Similar to the protective effects of mangiferin, overexpression of BMP2 suppressed not only Dex-induced cytotoxicity, but also ROS generation, and the secretion of TNF-α, IL-6 and M-CSF. In conclusion, the results of the present study are the first, to the best of our knowledge, to demonstrate that mangiferin protects MC3T3-E1 cells against Dex-induced apoptosis and oxidative stress by activating the BMP2/Smad-1 signaling pathway.

Valence State Manipulation of Cerium Oxide Nanoparticles on a Titanium Surface for Modulating Cell Fate and Bone Formation

Understanding cell-biomaterial interactions is critical for the control of cell fate for tissue engineering and regenerative medicine. Here, cerium oxide nanoparticles (CeONPs) are applied at different Ce4+/Ce3+ ratios (i.e., 0.46, 1.23, and 3.23) to titanium substrate surfaces by magnetron sputtering and vacuum annealing. Evaluation of the cytotoxicity of the modified surface to cultured rat bone marrow mesenchymal stem cells (BMSCs) reveals that the cytocompatibility and cell proliferation are proportional to the increases in Ce4+/Ce3+ ratio on titanium surface. The bone formation capability induced by these surface modified titanium alloys is evaluated by implanting various CeONP samples into the intramedullary cavity of rat femur for 8 weeks. New bone formation adjacent to the implant shows a close relationship to the surface Ce4+/Ce3+ ratio; higher Ce4+/Ce3+ ratio achieves better osseointegration. The mechanism of this in vivo outcome is explored by culturing rat BMSCs and RAW264.7 murine macrophages on CeONP samples for different durations. The improvement in osteogenic differentiation capability of BMSCs is directly proportional to the increased Ce4+/Ce3+ ratio on the titanium surface. Increases in the Ce4+/Ce3+ ratio also elevate the polarization of the M2 phenotype of RAW264.7 murine macrophages, particularly with respect to the healing-associated M2 percentage and anti-inflammatory cytokine secretion. The manipulation of valence states of CeONPs appears to provide an effective modulation of the osteogenic capability of stem cells and the M2 polarization of macrophages, resulting in favorable outcomes of new bone formation and osseointegration.

Trimetallic Nitride Endohedral Fullerenes Carboxyl-Gd3N@C80: A New Theranostic Agent for Combating Oxidative Stress and Resolving Inflammation

Antioxidative and anti-inflammatory effects of trimetallic nitride endohedral fullerenes carboxyl-Gd₃N@C₈₀, a newly developed magnetic resonance imaging (MRI) contrast agent, were investigated. All hydrochalarone and carboxyl-functionalized fullerenes showed effective radical (hydroxyl and superoxide anion) scavenging, whereas the carboxyl-Gd₃N@C₈₀ more efficiently attenuated lipopolysaccharide (LPS) induced oxidative stress in macrophages. Carboxyl-Gd₃N@C₈₀ also suppressed LPS-elicited mRNA expression of pro-inflammatory inducible nitric oxide synthase and tumor necrosis factor-alpha, and upregulated antioxidative enzyme axis Nrf2 and heme oxygenase-1, possibly via ERK but not AKT signaling pathways. Therefore, carboxyl-Gd₃N@C₈₀ held a great promise in becoming a novel theranostic nanoplatform for simultaneously deliver MRI contrast and therapeutic functions to inflammation-related diseases.

Mechanism of ROS scavenging and antioxidant signalling by redox metallic and fullerene nanomaterials: Potential implications in ROS associated degenerative disorders

BACKGROUND

The balance between oxidation and anti-oxidation is believed to be critical in maintaining healthy biological systems. However, our endogenous antioxidant defense systems are incomplete without exogenous antioxidants and, therefore, there is a continuous demand for exogenous antioxidants to prevent stress and ageing associated disorders. Nanotechnology has yielded enormous variety of nanomaterials (NMs) of which metallic and carbonic (mainly fullerenes) NMs, with redox property, have been found to be strong scavengers of ROS and antioxidants in preclinical in vitro and in vivo models.

SCOPE OF REVIEW

Redox activity of metal based NMs and membrane translocation time of fullerene NMs seem to be the major determinants in ROS scavenging potential exhibited by these NMs. A comprehensive knowledge about the effects of ROS scavenging NMs in cellular antioxidant signalling is largely lacking. This review compiles the mechanisms of ROS scavenging as well as antioxidant signalling of the aforementioned metallic and fullerene NMs.

MAJOR CONCLUSIONS

Direct interaction between NMs and proteins does greatly affect the corona/adsorption formation dynamics but such interaction does not provide the explanation behind diverse biological outcomes induced by NMs. Indirect interaction, however, that could occur via NMs uptake and dissolution, NMs ROS induction and ROS scavenging property, and NMs membrane translocation time seem to work as a central mode of interaction.

GENERAL SIGNIFICANCE

The usage of potential antioxidant NMs in biological systems would greatly impact the field of nanomedicine. ROS scavenging NMs hold great promise in the future treatment of ROS related degenerative disorders.

The Role of Reactive Oxygen Species in Adipogenic Differentiation

Interest in reactive oxygen species and adipocyte differentiation/adipose tissue function is steadily increasing. This is due in part to a search for alternative avenues for combating obesity, which results from the excess accumulation of adipose tissue. Obesity is a major risk factor for complex disorders such as cancer, type 2 diabetes, and cardiovascular diseases. The ability of mesenchymal stromal/stem cells (MSCs) to differentiate into adipocytes is often used as a model for studying adipogenesis in vitro. A key focus is the effect of both intra- and extracellular reactive oxygen species (ROS) on adipogenesis. The consensus from the majority of studies is that ROS, irrespective of the source, promote adipogenesis.The effect of ROS on adipogenesis is suppressed by antioxidants or ROS scavengers. Reactive oxygen species are generated during the process of adipocyte differentiation as well as by other cell metabolic processes. Despite many studies in this field, it is still not possible to state with certainty whether ROS measured during adipocyte differentiation are a cause or consequence of this process. In addition, it is still unclear what the exact sources are of the ROS that initiate and/or drive adipogenic differentiation in MSCs in vivo. This review provides an overview of our understanding of the role of ROS in adipocyte differentiation as well as how certain ROS scavengers and antioxidants might affect this process.

The reduction of oxidative stress by nanocomposite Fullerol decreases mucositis severity and reverts leukopenia induced by Irinotecan

Irinotecan is a useful chemotherapeutic agent for the treatment of several solid tumors. However, this therapy is associated with side effects, including leukopenia and mucositis. Reactive oxygen species (ROS) activate inflammatory pathways and contribute to Irinotecan-induced mucositis. Fullerol is a nanocomposite with anti-oxidant properties that may reduce tissue damage after inflammatory stimuli. In this paper, the effects of Fullerol and mechanisms of protection were investigated in a model of Irinotecan-induced mucositis. Mucositis was induced by an injection of Irinotecan per 4 days in C57BL/6. Fullerol or a vehicle was injected every 12h. On day 7, the intestines were removed to evaluate histological changes, leukocyte influx, and the production of cytokines and ROS. Irinotecan therapy resulted in weight loss, an increased clinical score and intestinal injury. Treatment with Fullerol attenuated weight loss, decreased clinical score and intestinal damage. Irinotecan also induced increased ROS production in enterocytes, oxidative stress, IL-1β production, neutrophil and eosinophil influx in the ileum. Fullerol treatment decreased production of ROS in the enterocytes, oxidative stress, IL-1β production, neutrophil and eosinophil influx in the ileum. Irinotecan therapy also induced leukopenia in an ROS-dependent manner because leukopenia reverted in WT mice treated with Fullerol or Apocynin or in Gp91phox(-/-) mice. Mice treated with Irinotecan presented less melanoma tumor growth compared to the control group. Fullerol does not interfere in the anti-tumor action of Irinotecan. Fullerol has a great pharmacology potential to decreases the severity of mucositis and of leukopenia during chemotherapy treatment.

Fullerene mediates proliferation and cardiomyogenic differentiation of adipose-derived stem cells via modulation of MAPK pathway and cardiac protein expression

Zero-dimensional fullerenes can modulate the biological behavior of a variety of cell lines. However, the effects and molecular mechanisms of proliferation and cardiomyogenic differentiation in brown adipose-derived stem cells (BADSCs) are still unclear. In this study, we report the initial biological effects of fullerene-C₆₀ on BADSCs at different concentrations. Results suggest that fullerene-C₆₀ has no cytotoxic effects on BADSCs even at a concentration of 100 μg/mL. Fullerene-C₆₀ improves the MAPK expression level and stem cell survival, proliferation, and cardiomyogenesis. Further, we found that the fullerene-C₆₀ modulates cardiomyogenic differentiation. Fullerene-C₆₀ improves the expression of cardiomyocyte-specific proteins (cTnT and α-sarcomeric actinin). At elevated concentration, fullerene-C₆₀ reduces the incidence of diminished spontaneous cardiac differentiation of BADSCs with time. At the genetic level, fullerene-C₆₀ (5 μg/mL) also improves the expression of cTnT. In addition, fullerene-C₆₀ promotes the formation of gap junction among cells. These findings have important implications for clinical application of fullerenes in the treatment of myocardial infarction.

Growth and potential damage of human bone-derived cells cultured on fresh and aged C60/Ti films

Thin films of binary C60/Ti composites, with various concentrations of Ti ranging from ~ 25% to ~ 70%, were deposited on microscopic glass coverslips and were tested for their potential use in bone tissue engineering as substrates for the adhesion and growth of bone cells. The novelty of this approach lies in the combination of Ti atoms (i.e., widely used biocompatible material for the construction of stomatological and orthopedic implants) with atoms of fullerene C60, which can act as very efficient radical scavengers. However, fullerenes and their derivatives are able to generate harmful reactive oxygen species and to have cytotoxic effects. In order to stabilize C60 molecules and to prevent their possible cytotoxic effects, deposition in the compact form of Ti/C60 composites (with various Ti concentrations) was chosen. The reactivity of C60/Ti composites may change in time due to the physicochemical changes of molecules in an air atmosphere. In this study, we therefore tested the dependence between the age of C60/Ti films (from one week to one year) and the adhesion, morphology, proliferation, viability, metabolic activity and potential DNA damage to human osteosarcoma cells (lines MG-63 and U-2 OS). After 7 days of cultivation, we did not observe any negative influence of fresh or aged C60/Ti layers on cell behavior, including the DNA damage response. The presence of Ti atoms resulted in improved properties of the C60 layers, which became more suitable for cell cultivation.

Steroid-associated osteonecrosis: Epidemiology, pathophysiology, animal model, prevention, and potential treatments (an overview)

Steroid-associated osteonecrosis (SAON) is a common orthopaedic problem caused by administration of corticosteroids prescribed for many nonorthopaedic medical conditions. We summarised different pathophysiologies of SAON which have adverse effects on multiple systems such as bone marrow stem cells (BMSCs) pool, bone matrix, cell apoptosis, lipid metabolism, and angiogenesis. Different animal models were introduced to mimic the pathophysiology of SAON and for testing the efficacy of both prevention and treatment effects of various chemical drugs, biological, and physical therapies. According to the classification of SAON, several prevention and treatment methods are applied at the different stages of SAON. For the current period, Chinese herbs may also have the potential to prevent the occurrence of SAON. In the future, genetic analysis might also be helpful to effectively predict the development of ON and provide information for personalised prevention and treatment of patients with SAON.

Icariin may benefit the mesenchymal stem cells of patients with steroid-associated osteonecrosis by ABCB1-promoter demethylation: a preliminary study

In this study, we found out a previously undefined function of icariin which restored the dynamic balance between osteogenic and adipogenic differentiation of mesenchymal stem cells (MSCs) in patients with osteonecrosis of femoral head (ONFH) via ABCB1-promoter demethylation. These findings provided important information regarding potential implication of icariin targeting epigenetic changes for the treatment of steroid -associated ONFH.

INTRODUCTION

Here, we investigated whether icariin can also exert a beneficial role in the reactivation of MSCs in the patients with steroid-associated ONFH via ABCB1-promoter demethylation.

METHODS

Bone marrow was collected from the proximal femur in patients with steroid-associated ONFH (n = 20) and patients with new femoral neck fractures (n = 22), and then MSCs were isolated. We investigated cell viability, intracellular reactive oxygen species (ROS) level, mitochondrial membrane potential (MMP), P-glycoprotein (P-gp) activity, the transcript levels of ABCB1 and oxidative stress-related genes, methylation extent at CpG islands of ABCB1 promoter, and osteogenic and adipogenic differentiation ability of MSCs from the femoral neck fractures group and from the steroid-associated ONFH group treated with or without icariin.

RESULTS

We observed that MSCs from the steroid-associated ONFH group showed reduced proliferation ability, elevated ROS level, depressed MMP, weakened osteogenesis, and enhanced adipogenesis while low P-gp activity, transcription level of ABCB1, and oxidative stress-related genes as well as aberrant CpG islands hypermethylation of ABCB1 were also noted in steroid-associated ONFH group. Treatment with icariin obviously induced de novo P-gp expression, decreased oxidative stress, and promoted osteogenesis.

CONCLUSION

Icariin may be a potential drug targeting epigenetic changes for the treatment of steroid-associated ONFH.

Long-term effects of nanoparticles on nutrition and metabolism

Nanoparticles have shown great potential in biological and biomedical applications due to their distinct physical and chemical properties. In the meanwhile, the biosafety of nanoparticles has also raised intense concerns worldwide. To address such concerns, great efforts have been made to examine short-term effects of nanoparticles on cell survival and proliferation. More recently, exploration of long-term effects of nanomaterials, particularly those with promising biomedical applications in vivo, has aroused significant interest. For example, gold nanoparticles (AuNPs) are generally considered non-toxic to cell growth, whereas recent studies suggest that AuNPs might have long-term effects on cellular metabolism and energy homeostasis. In this Review, recent advances in this direction are summarized. Further, possible mechanisms under which nanoparticles regulate metabolic signaling pathways, potential long-term effects on cellular anabolic or catabolic processes, and their implications in human health and metabolic disorders are discussed.

Antioxidative fullerol promotes osteogenesis of human adipose-derived stem cells

Antioxidants were implicated as potential reagents to enhance osteogenesis, and nano-fullerenes have been demonstrated to have a great antioxidative capacity by both in vitro and in vivo experiments. In this study, we assessed the impact of a polyhydroxylated fullerene, fullerol, on the osteogenic differentiation of human adipose-derived stem cells (ADSCs). Fullerol was not toxic against human ADSCs at concentrations up to 10 μM. At a concentration of 1 μM, fullerol reduced cellular reactive oxygen species after a 5-day incubation either in the presence or in the absence of osteogenic media. Pretreatment of fullerol for 7 days increased the osteogenic potential of human ADSCs. Furthermore, when incubated together with osteogenic medium, fullerol promoted osteogenic differentiation in a dose-dependent manner. Finally, fullerol proved to promote expression of FoxO1, a major functional isoform of forkhead box O transcription factors that defend against reactive oxygen species in bone. Although further clarification of related mechanisms is required, the findings may help further development of a novel approach for bone repair, using combined treatment of nano-fullerol with ADSCs.

Antioxidative nanofullerol prevents intervertebral disk degeneration

Compelling evidence suggests that reactive oxygen species (ROS) play a pivotal role in disk degeneration. Fullerol nanoparticles prepared in aqueous solution have been demonstrated to have outstanding ability to scavenge ROS. In this report, in vitro and in vivo models were used to study the efficacy of fullerol in preventing disk degeneration. For in vitro experiments, a pro-oxidant H₂O₂ or an inflammatory cytokine interleukin (IL)-1β was employed to induce degenerated phenotypes in human nucleus pulposus cells encapsulated in alginate beads, and fullerol was added in the culture medium. For the animal study, an annulus-puncture model with rabbit was created, and fullerol was injected into disks. It was shown that cytotoxicity and cellular ROS level induced by H₂O₂ were significantly diminished by fullerol. IL-1β-induced nitric oxide generation in culture medium was suppressed by fullerol as well. Gene-profile and biochemical assays showed that fullerol effectively reversed the matrix degradation caused by either H₂O₂ or IL-1β. The animal study delineated that intradiskal injection of fullerol prevented disk degeneration, increasing water and proteoglycan content and inhibiting ectopic bone formation. These results suggest that antioxidative fullerol may have a potential therapeutic application for disk degeneration.

The applications of buckminsterfullerene C60 and derivatives in orthopaedic research

Abstract Buckminsterfullerene C60 and derivatives have been extensively explored in biomedical research due to their unique structure and unparalleled physicochemical properties. C60 is characterized as a "free radical sponge" with an anti-oxidant efficacy several hundred-fold higher than conventional anti-oxidants. Also, the C60 core has a strong electron-attracting ability and numerous functional compounds with widely different properties can be added to this fullerene cage. This review focused on the applications of C60 and derivatives in orthopaedic research, such as the treatment of cartilage degeneration, bone destruction, intervertebral disc degeneration (IVDD), vertebral bone marrow disorder, radiculopathy, etc., as well as their toxicity in vitro and in vivo. We suggest that C60 and derivatives, especially the C60 cores coupled with functional groups presenting new biological and pharmacological activities, are advantageous in orthopaedic research and will be promising in clinical performance for musculoskeletal disorders treatment; however, the pharmacokinetics and toxicology of these agents as local/systemic administration need to be carefully determined.

Fullerene-biomolecule conjugates and their biomedicinal applications

Fullerenes are among the strongest antioxidants and are characterized as “radical sponges.” The research on biomedicinal applications of fullerenes has achieved significant progress since the landmark publication by Friedman et al in 1993. Fullerene–biomolecule conjugates have become an important area of research during the past 2 decades. By a thorough literature search, we attempt to update the information about the synthesis of different types of fullerene–biomolecule conjugates, including fullerene-containing amino acids and peptides, oligonucleotides, sugars, and esters. Moreover, we also discuss in this review recently reported data on the biological and pharmaceutical utilities of these compounds and some other fullerene derivatives of biomedical importance. While within the fullerene–biomolecule conjugates, in which fullerene may act as both an antioxidant and a carrier, specific targeting biomolecules conjugated to fullerene will undoubtedly strengthen the delivery of functional fullerenes to sites of clinical interest.

Functional TRPV and TRPM channels in human preadipocytes

Preadipocytes are widely used as an in vitro model to investigate proliferation, adipogenic differentiation, and lipodystrophy; however, cellular physiology and biology are not fully understood in human preadipocytes. The present study was to investigate the expression of transient receptor potential (TRP) channels in human preadipocytes and their potential roles in regulating proliferation and adipogenic differentiation using approaches of confocal microscopy, whole-cell patch voltage-clamp, reverse transcription polymerase chain reaction, Western blot, etc. We found that TRPV2, TRPV4, and TRPM7 channels were abundantly expressed in human preadipocytes. The intracellular Ca(2+) transient activated by the TRPV2 activator probenecid was reversed or prevented by ruthenium red, a TRPV2 blocker. The TRPV4 channel activator, 4α-phorbol 12-13-dicaprinate, enhanced intracellular Ca(2+) oscillations, and the effect was inhibited by the TRPV4 blocker RN-1734. TRPM7 current was recorded with dialysis of Mg(2+)-free pipette solution, which was inhibited by the TRP channel blocker 2-aminoethoxydiphenyl borate and enhanced by acidic extracellular pH. Silencing TRPV2 or TRPM7, but not TRPV4, significantly reduced cell proliferation via inhibiting cyclin D1, cyclin E, and p-ERK1/2. Interestingly, individually silencing these three channels decreased adipogenic differentiation of human preadipocytes by reducing p-Akt kinase. Our results demonstrate for the first time that functional TRPV2, TRPV4, and TRPM7 channels are abundantly expressed in human preadipocytes. TRPV2 and TRPM7, but not TRPV4, regulate cell proliferation via activating cyclin D1, cyclin E, and p-ERK1/2, while they are all involved in adipogenesis in human preadipocytes via phosphorylating Akt kinase.

Aberrant CpG islands' hypermethylation of ABCB1 in mesenchymal stem cells of patients with steroid-associated osteonecrosis

OBJECTIVE

Patients carrying an ABCB1 polymorphism have a higher risk of developing osteonecrosis of the femoral head (ONFH). We investigated whether aberrant dinucleotide CpG islands' hypermethylation of ABCB1 gene existed in mesenchymal stem cells (MSC) of patients with ONFH, which results in cell dysfunction.

METHODS

Bone marrow was collected from the proximal femur of patients with glucocorticoid (GC)-associated ONFH (n = 22) and patients with new femoral neck fractures (n = 25). MSC were isolated by density gradient centrifugation. We investigated cell viability, intracellular reactive oxygen species (ROS) level, mitochondrial membrane potential (MMP), the amount of P-glycoprotein (P-gp) and ABCB1 transcripts, and methylation at CpG islands of ABCB1 promoter from both the femoral neck fractures group and the GC-associated ONFH group treated with or without the DNA methyltransferase inhibitor, 5'-Aza-2-deoxycytidine (5'-Aza-dC).

RESULTS

We observed that MSC from GC-associated ONFH groups showed reduced proliferation ability, elevated ROS levels, and depressed MMP when compared with the other 2 groups. Low levels of P-gp and ABCB1 transcript, as well as ABCB1 gene hypermethylation, in patients with GC-associated ONFH were also noted. Treatment with 5'-Aza-dC rapidly restored ABCB1 expression. Analysis of general expression revealed that aberrant CpG islands' hypermethylation of ABCB1 caused sensitivity to GC and induced changes in the proliferation and oxidative stress of MSC under GC administration.

CONCLUSION

These data suggest that aberrant CpG islands' hypermethylation of ABCB1 gene may be responsible for individual differences in the development of GC-associated ONFH.

Redox mechanisms in regulation of adipocyte differentiation: beyond a general stress response

In this review, we summarize advances in our understanding of redox-sensitive mechanisms that regulate adipogenesis. Current evidence indicates that reactive oxygen species may act to promote both the initiation of adipocyte lineage commitment of precursor or stem cells, and the terminal differentiation of preadipocytes to mature adipose cells. These can involve redox regulation of pathways mediated by receptor tyrosine kinases, peroxisome proliferator-activated receptor γ (PPARγ), PPARγ coactivator 1α (PGC-1α), AMP-activated protein kinase (AMPK), and CCAAT/enhancer binding protein β (C/EBPβ). However, the precise roles of ROS in adipogenesis in vivo remain controversial. More studies are needed to delineate the roles of reactive oxygen species and redox signaling mechanisms, which could be either positive or negative, in the pathogenesis of obesity and related metabolic disorders.