A novel approach for the prevention of ionizing radiation-induced bone loss using a designer multifunctional cerium oxide nanozyme

The disability, mortality and costs due to ionizing radiation (IR)-induced osteoporotic bone fractures are substantial and no effective therapy exists. Ionizing radiation increases cellular oxidative damage, causing an imbalance in bone turnover that is primarily driven via heightened activity of the bone-resorbing osteoclast. We demonstrate that rats exposed to sublethal levels of IR develop fragile, osteoporotic bone. At reactive surface sites, cerium ions have the ability to easily undergo redox cycling: drastically adjusting their electronic configurations and versatile catalytic activities. These properties make cerium oxide nanomaterials fascinating. We show that an engineered artificial nanozyme composed of cerium oxide, and designed to possess a higher fraction of trivalent (Ce³⁺) surface sites, mitigates the IR-induced loss in bone area, bone architecture, and strength. These investigations also demonstrate that our nanozyme furnishes several mechanistic avenues of protection and selectively targets highly damaging reactive oxygen species, protecting the rats against IR-induced DNA damage, cellular senescence, and elevated osteoclastic activity in vitro and in vivo. Further, we reveal that our nanozyme is a previously unreported key regulator of osteoclast formation derived from macrophages while also directly targeting bone progenitor cells, favoring new bone formation despite its exposure to harmful levels of IR in vitro. These findings open a new approach for the specific prevention of IR-induced bone loss using synthesis-mediated designer multifunctional nanomaterials.

The energetics of carbonated PuO2 surfaces affects nanoparticle morphology: a DFT+U study

Radiolytic corrosion of actinide materials represent an issue for the long term storage and disposal of nuclear materials. Molecular species adsorbed at the surface of the actinides may impact the rate of radiolysis, and as the surfaces corrode, the soluble toxic and radioactive species leach into groundwater. It is therefore critical to characterise the surface composition of actinides. Here, we employ ab initio modelling to determine the surface composition of PuO2 with respect to adsorbed CO2. We found that CO2 interacts strongly with the surface forming carbonate species. By mapping the energetics of this interaction, we then calculate the temperature of desorption, finding that surface morphology has a strong impact on the adsorption of CO2, with the {100} being the most and the {111} the least affected by carbonation. Finally, we predict the effect of carbonation on the morphology of PuO2 nanoparticles as a function of temperature and pressure, finding that truncated octahedral is the preferred morphology. This modelling strategy helps characterise surface compensition and nanoparticle morphology, and we discuss the implication for radiolytically driven dispersal of material into the environment.

The cytoskeleton adaptor protein ankyrin-1 is upregulated by p53 following DNA damage and alters cell migration

The integrity of the genome is maintained by a host of surveillance and repair mechanisms that are pivotal for cellular function. The tumour suppressor protein p53 is a major component of the DNA damage response pathway and plays a vital role in the maintenance of cell-cycle checkpoints. Here we show that a microRNA, miR-486, and its host gene ankyrin-1 (ANK1) are induced by p53 following DNA damage. Strikingly, the cytoskeleton adaptor protein ankyrin-1 was induced over 80-fold following DNA damage. ANK1 is upregulated in response to a variety of DNA damage agents in a range of cell types. We demonstrate that miR-486-5p is involved in controlling G1/S transition following DNA damage, whereas the induction of the ankyrin-1 protein alters the structure of the actin cytoskeleton and sustains limited cell migration during DNA damage. Importantly, we found that higher ANK1 expression correlates with decreased survival in cancer patients. Thus, these observations highlight ANK1 as an important effector downstream of the p53 pathway.

Analysis of a care planning intervention for reducing depression in older people in residential care

Approximately 40% of older people in residential care have significant symptoms of depression. A training and care-planning approach to reducing depression was implemented for 114 depressed residents living in 14 residential care homes in North Yorkshire, UK. Care staff were offered brief mental health training by community mental health teams for older people. They were then assigned to work individually with residents in implementing the care-planning intervention, which was aimed at alleviating depression and any health, social or emotional factors that might contribute to the resident's depression. Clinically significant improvements in depression scores were associated with implementation of the care-planning intervention as evidenced by changes in scores on the Geriatric Mental State Schedule-Depression Scale. There was evidence of an interaction between the power of the intervention and degree of dementia. These improvements were not accounted for by any changes in psychotropic medication. The training was highly valued by care staff and heads of homes, and they considered that the care-planning intervention represented an improvement in quality of care for all residents, irrespective of levels of dementia. Staff also reported improvements in morale and increased confidence in the caring role as a result of their participation. The limitations of this study are discussed. On the basis of a growing body of evidence, it is argued that there is an urgent need for a suitably powered randomised controlled trial and economic evaluation, to test the cost-effectiveness of personalised care planning interventions aimed at reducing depression in older people in residential care.

The effects of caffeine on psychological functioning

The past few years have witnessed a growing literature on the behavioural, cognitive and performance effects, both beneficial and hazardous, of caffeine ingestion. A brief overview of these studies is provided and methodological difficulties discussed. Disagreement over such factors as the quantity of caffeine required to produce deleterious effects, difficulties obtaining valid measures of caffeine intake from self-reports and differing interpretations of tolerance levels and absorption rates between studies, often prevent the derivation of meaningful results. The need for a rigorous, scientific appraisal of the effects of caffeine on psychological functioning is emphasised. This requires agreement about criteria referred to above, a more valid data base, and in some cases, the adoption of alternative methodology.