The spaceflight environment exposes biological systems to microgravity and cosmic radiation, which are factors known to induce oxidative stress and neurodegenerative processes. As the central nervous system is highly susceptible to disruptions in redox homeostasis, the development of effective strategies to safeguard astronaut health and cognitive function during extended space missions has become imperative. In this study, we investigate cerium oxide nanoparticles (nanoceria, NC) as an antioxidant agent for human neuron-like cells aboard the International Space Station. Nanoceria demonstrated excellent biocompatibility, strong antioxidant properties, and the ability to stimulate neurite extension under both Earth gravity and simulated microgravity. Following the return of the samples to Earth, transcriptomic analyses revealed that nanoceria effectively counteracted the detrimental transcriptional alterations triggered by spaceflight stressors, thereby maintaining neuronal homeostasis. Importantly, the expression of genes involved in antioxidant defense, mitochondrial activity, and dopamine metabolism remained stable in nanoceria-treated neurons, in contrast to the dysregulation observed in untreated controls. These findings position cerium oxide nanoparticles as promising antioxidant neuroprotectants for long-duration space missions and related neurodegenerative conditions.

The obtainment of innovative models recalling complex tumour architectures and activitiesin vitrois a challenging drive in the understanding of pathology molecular bases, yet it is a crucial path to the identification of targets for advanced oncotherapy. Cell environment recapitulation by 3D scaffolding and gravitational unloading of cell cultures represent powerful means in tumour biomimicry processes, but their simultaneous adoption has consistently been explored only in the latest decade. Here, an unprecedented bioengineering approach capitalizing on spaceflight biology practice is proposed for modelling of glioblastoma multiforme, a highly aggressive neoplasm that affects the central nervous system and has poorly effective pharmacological and radiological countermeasures. Tumour modelling was pursued by the original implementation of two-photon polymerization in fast prototyping of 3D scaffolds on flexible substrates for U87-MG glioma cell culture, and by the exposure of cell-laden scaffolds to simulated microgravity (s-μg). Realistic spaceflight conditions were applied to collect preliminary information suitable for testing of U87-MG cell-laden scaffold in low Earth orbit. Responses of glioma cells anchored to 3D scaffolds were investigated by microscopy, quantitative reverse transcription-polymerase chain reaction and proteomic analyses, revealing synergic regulatory effects of cell scaffolding and s-μg on markers of tumour cell growth, metabolism and invasiveness.

Exposure to microgravity and cosmic radiation during spaceflight is responsible for oxidative stress onset, contributing to neuronal dysfunction and degeneration. The central nervous system is particularly vulnerable to redox imbalance and requires effective countermeasures to ensure astronaut health and performance on long-duration missions. In this study, the neuroprotective properties of polydopamine nanoparticles (PDNPs), known for their antioxidant activity, are investigated on neuron-like cells exposed to different gravitational and radiation regimes. Culture conditions included administration of PDNPs and permanence aboard the International Space Station (ISS) or on a random positioning machine. Transcriptomic analyses are conducted to assess gene expression alterations associated with oxidative stress, nuclear and mitochondrial integrity, and dopamine metabolism. In-flight, PDNP treatment mitigates the transcriptional changes induced by space stressors, preserving neuronal homeostasis. Notably, expression of key antioxidant defense genes, mitochondrial function markers and dopamine metabolism genes is stabilized in PDNP-treated neurons. This study provides preliminary evidence on the efficacy of PDNPs in protecting neuronal cells from the combined stressors associated with spaceflight: these findings suggest PDNPs as a promising countermeasure for space-induced neurodegeneration and support their potential translational application in the treatment of oxidative stress-related neurodegenerative pathologies on Earth.

Progress in mechanobiology allowed us to better understand the important role of mechanical forces in the regulation of biological processes. Space research in the field of life sciences clearly showed that gravity plays a crucial role in biological processes. The space environment offers the unique opportunity to carry out experiments without gravity, helping us not only to understand the effects of gravitational alterations on biological systems but also the mechanisms underlying mechanoperception and cell/tissue response to mechanical and gravitational stresses. Despite the progress made so far, for future space exploration programs it is necessary to increase our knowledge on the mechanotransduction processes as well as on the molecular mechanisms underlying microgravity-induced cell and tissue alterations. This white paper reports the suggestions and recommendations of the SciSpacE Science Community for the elaboration of the section of the European Space Agency roadmap “Biology in Space and Analogue Environments” focusing on “How are cells and tissues influenced by gravity and what are the gravity perception mechanisms?” The knowledge gaps that prevent the Science Community from fully answering this question and the activities proposed to fill them are discussed.

Periodically, the European Space Agency (ESA) updates scientific roadmaps in consultation with the scientific community. The ESA SciSpacE Science Community White Paper (SSCWP) 9, "Biology in Space and Analogue Environments", focusses in 5 main topic areas, aiming to address key community-identified knowledge gaps in Space Biology. Here we present one of the identified topic areas, which is also an unanswered question of life science research in Space: "How to Obtain an Integrated Picture of the Molecular Networks Involved in Adaptation to Microgravity in Different Biological Systems?" The manuscript reports the main gaps of knowledge which have been identified by the community in the above topic area as well as the approach the community indicates to address the gaps not yet bridged. Moreover, the relevance that these research activities might have for the space exploration programs and also for application in industrial and technological fields on Earth is briefly discussed.

Oxidative stress is a widespread causative agent of disease. Together with its general relevance for biomedicine, such a dynamic is recognizably detrimental to space exploration. Among other solutions, cerium oxide nanoparticles (or nanoceria, NC) display a long-lasting, self-renewable antioxidant activity. In a previous experiment, we evaluated oxidative imbalance in rat myoblasts in space, aboard the International Space Station, and unveiled possible protective effects from NC through RNA sequencing. Here, we focus on the myoblast response to NC on land by means of proteomics, defining a list of proteins that putatively react to NC and confirming nucleosomes/histones as likely mediators of its molecular action. The proteomics data set we present here and its counterpart from the space study share four factors. These are coherently either up- (Hist1h4b) or down-regulated (Gnl3, Mtdh, Trip12) upon NC exposure.

Spaceflight typically exerts detrimental effects on living organisms by promoting/accelerating some degenerative processes associated with aging and pathology onset on Earth, like muscle degeneration. As possible countermeasures to spaceflight effects, a few recent studies successfully tested the administration of nanomaterials for tuning of cellular activities and for promotion of certain cell phenotypes in microgravity, but largely missed investigation of early interactions of these nanomaterials with their cellular targets under altered gravity conditions. This study aims at filling this gap by elucidation of early interactions of a selected typology of redox-active nanoparticles (cerium oxide nanoparticles, also termed nanoceria, NC) with proliferating human skeletal myoblasts (HSkM) by concomitant exposure to simulated microgravity (achieved by a random positioning machine, RPM). To this purpose, NC were synthesized by a direct precipitation method and were chemically, structurally, and functionally characterized by several independent techniques prior to administration to skeletal muscle cell cultures and loading on the RPM. Confocal and electron microscopy evidence of nanoparticle internalization by several mechanisms (mostly involving macropinocytosis) in HSkM is provided, along with evidence of transcriptional regulation of key antioxidant response markers (Nos1, Sod2, and Sod3), promising oxidative stress alleviation and muscle protection under mechanical unloading conditions.

The present white paper concerns the indications and recommendations of the SciSpacE Science Community to make progress in filling the gaps of knowledge that prevent us from answering the question: “How Do Gravity Alterations Affect Animal and Human Systems at a Cellular/Tissue Level?” This is one of the five major scientific issues of the ESA roadmap “Biology in Space and Analogue Environments”. Despite the many studies conducted so far on spaceflight adaptation mechanisms and related pathophysiological alterations observed in astronauts, we are not yet able to elaborate a synthetic integrated model of the many changes occurring at different system and functional levels. Consequently, it is difficult to develop credible models for predicting long-term consequences of human adaptation to the space environment, as well as to implement medical support plans for long-term missions and a strategy for preventing the possible health risks due to prolonged exposure to spaceflight beyond the low Earth orbit (LEO). The research activities suggested by the scientific community have the aim to overcome these problems by striving to connect biological and physiological aspects in a more holistic view of space adaptation effects.

In the past decades, bone tissue engineering developed and exploited many typologies of bioreactors, which, besides providing proper culture conditions, aimed at integrating those bio-physical stimulations that cells experience in vivo, to promote osteogenic differentiation. Nevertheless, the highly challenging combination and deployment of many stimulation systems into a single bioreactor led to the generation of several unimodal bioreactors, investigating one or at mostly two of the required biophysical stimuli. These systems miss the physiological mimicry of bone cells environment, and often produced contrasting results, thus making the knowledge of bone mechanotransduction fragmented and often inconsistent. To overcome this issue, in this study we developed a perfusion and electroactive-vibrational reconfigurable stimulation bioreactor to investigate the differentiation of SaOS-2 bone-derived cells, hosting a piezoelectric nanocomposite membrane as cell culture substrate. This multimodal perfusion bioreactor is designed based on a numerical (finite element) model aimed at assessing the possibility to induce membrane nano-scaled vibrations (with ~12 nm amplitude at a frequency of 939 kHz) during perfusion (featuring 1.46 dyn cm-2 wall shear stress), large enough for inducing a physiologically-relevant electric output (in the order of 10 mV on average) on the membrane surface. This study explored the effects of different stimuli individually, enabling to switch on one stimulation at a time, and then to combine them to induce a faster bone matrix deposition rate. Biological results demonstrate that the multimodal configuration is the most effective in inducing SaOS-2 cell differentiation, leading to 20-fold higher collagen deposition compared to static cultures, and to 1.6- and 1.2-fold higher deposition than the perfused- or vibrated-only cultures. These promising results can provide tissue engineering scientists with a comprehensive and biomimetic stimulation platform for a better understanding of mechanotransduction phenomena beyond cells differentiation.

EDITORIAL article Front. Mol. Biosci., 18 October 2022Sec. Nanobiotechnology Volume 9 - 2022 | https://doi.org/10.3389/fmolb.2022.1044063

Smart materials able to respond to an external stimulus or an environmental condition represent milestone developments in modern medicine. Among them, zinc oxide (ZnO) is a highly intriguing inorganic material with versatile morphologies/shapes and multifunctional properties like piezoelectricity, enhanced reactive oxygen species (ROS) generation, and antimicrobial ones. Here, the fabrication of smart ZnO-based films is shown that can remotely be activated by ultrasound (US). US exposure induces electrical potentials on the fabricated devices that can be exploited to stimulate electrically responsive cells or promote ROS generation for cancer treatment. ZnO microparticles with surface nanostructuring are thus synthesized and processed in the form of a paste to deposit thin films on flexible polymeric supports. ZnO paste formulation and the fabrication procedure of the final device are optimized in terms of uniformity, hydrophilicity, and purity. Graphene oxide and poly(2-hydroxyethyl methacrylate) are also layered onto the ZnO films in order to provide the devices with additional functionalities. ROS generation and electro-mechanical performances upon US stimulation are evaluated for all of the developed devices. Finally, biocompatibility studies are conducted with osteoblast-like cell cultures for possible applications in the contexts of bone tissue engineering/therapy.

Parkinson's disease (PD) is a progressive neurodegenerative disease with no satisfactory therapy options. Similar to other neurodegenerative conditions, such as Alzheimer's and Huntington's diseases, oxidative stress plays a key factor in the neurodegeneration process. To counteract the uncontrolled increase of reactive oxygen species (ROS) and oxidative stress-dependent cell death, several preclinical and clinical tests exploit natural-derived organic antioxidants, such as polyphenols. Despite some promising results, free antioxidants show scarce brain accumulation and may exhaust their scavenging activity before reaching the brain. In this work, we developed an antioxidant therapeutic nanoplatform consisting of nano-sized functionalized liposomes loaded with selected polyphenol-rich vegetal extracts with high blood-brain barrier crossing capabilities. The antioxidant extracts were obtained from the grape seeds and skins as a byproduct of wine production (i.e., pomace), following a sustainable circular approach with reduced environmental impact. The antioxidant nanoplatform was successfully tested in a relevant in vitro model of PD, where it completely rescued the ROS levels, prevented the aggregation of α-synuclein fibrils, and restored cell viability, paving the way for preclinical translation of the approach.

Smart materials able to respond to an external stimulus or an environmental condition represent milestone developments in modern medicine. Among them, zinc oxide (ZnO) is a highly intriguing inorganic material with versatile morphologies/shapes and multifunctional properties like piezoelectricity, enhanced reactive oxygen species (ROS) generation, and antimicrobial ones. Here, the fabrication of smart ZnO‐based films is shown that can remotely be activated by ultrasound (US). US exposure induces electrical potentials on the fabricated devices that can be exploited to stimulate electrically responsive cells or promote ROS generation for cancer treatment. ZnO microparticles with surface nanostructuring are thus synthesized and processed in the form of a paste to deposit thin films on flexible polymeric supports. ZnO paste formulation and the fabrication procedure of the final device are optimized in terms of uniformity, hydrophilicity, and purity. Graphene oxide and poly(2‐hydroxyethyl methacrylate) are also layered onto the ZnO films in order to provide the devices with additional functionalities. ROS generation and electro‐mechanical performances upon US stimulation are evaluated for all of the developed devices. Finally, biocompatibility studies are conducted with osteoblast‐like cell cultures for possible applications in the contexts of bone tissue engineering/therapy.

Il rinnovato interesse per l'esplorazione dello spazio ha evidenziato la necessita di una comprensione profonda dei rischi per l'equipaggio e delle opportunita commerciali insite nel volo, sia in bassa orbita terrestre che nello spazio profondo. L'esplorazione spaziale rappresenta una sfida complessa per gli organismi di origine terrestre, comportando per essi notevoli stress di natura fisica (transizioni gravitazionali, permanenza in microgravita ed assorbimento di radiazioni cosmiche), ma anche chimica, microbiologica e psicologica. Fortemente ostile alla vita, l'ambiente spaziale rappresenta inoltre un prezioso banco di prova di strumenti innovativi per il contrasto di numerosi fenomeni degenerativi associati all'invecchiamento, nonche all'insorgenza di malattie a Terra. Fra questi strumenti, quelli nanotecnologici iniziano a mostrare evidenze promettenti di un valido supporto alla vita nello spazio.

Largely utilized in photocatalysis and photovoltaicis, titanium dioxide (also termed "titania") nanostructures are increasingly finding applications in different fields of biomedical research. Their versatile physicochemical characteristics and their high compatibility with biological systems have indeed motivated their introduction—among the many areas of investigation—also in tissue engineering, drug delivery, and cancer therapy. Here, the most recent findings in these fields will be presented with a special focus on properties tunable by exposure to a contactless source of stimulation, which make titanium dioxide nanostructures actual "smart" materials. Current challenges and prospective opportunities will also be discussed by taking into consideration composite titanium dioxide–based nanostructures enriched in surface and bulk features.

Autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS) is a neurological disease characterized by autosomal recessive mutations in the sacsin gene (SACS), that cause in patients progressive cerebellar atrophy, damage of the peripheral nerves, and cognitive impairment. No effective therapies have been proposed for ARSACS, even if some evidences suggest that powerful antioxidant agents can be considered as a therapeutic tool. Resveratrol (Res) is a natural polyphenol compound derived from vegetal sources, the application of which in biomedicine is increasing in the latest years owing to its significant therapeutic effects, in particular in neurodegenerative diseases. In this study, we provide evidences about its potential exploitation in the treatment of ARSACS. Because of the low solubility of Res in physiological media, a nanoplatform based on nanostructured lipid carriers is proposed for its encapsulation and delivery. Resveratrol-loaded nanostructured lipid carriers (Res-NLCs) have been synthetized, characterized, and tested on healthy and ARSACS patient fibroblasts. Nanovectors displayed optimal stability and biocompatibility, and excellent antioxidant and anti-inflammatory activities. A comprehensive investigation at gene (with real-time quantitative RT-PCR) and protein (with proteomics) level demonstrated the therapeutic potential of Res-NLCs, encouraging future investigations on pre-clinical models.

For their remarkable biomimetic properties implying strong modulation of the intracellular and extracellular redox state, cerium oxide nanoparticles (also termed "nanoceria") were hypothesized to exert a protective role against oxidative stress associated with the harsh environmental conditions of spaceflight, characterized by microgravity and highly energetic radiations. Nanoparticles were supplied to proliferating C2C12 mouse skeletal muscle cells under different gravity and radiation levels. Biological responses were thus investigated at a transcriptional level by RNA next-generation sequencing. Lists of differentially expressed genes (DEGs) were generated and intersected by taking into consideration relevant comparisons, which led to the observation of prevailing effects of the space environment over those induced by nanoceria. In space, upregulation of transcription was slightly preponderant over downregulation, implying involvement of intracellular compartments, with the majority of DEGs consistently over- or under-expressed whenever present. Cosmic radiations regulated a higher number of DEGs than microgravity and seemed to promote increased cellular catabolism. By taking into consideration space physical stressors alone, microgravity and cosmic radiations appeared to have opposite effects at transcriptional levels despite partial sharing of molecular pathways. Interestingly, gene ontology denoted some enrichment in terms related to vision, when only effects of radiations were assessed. The transcriptional regulation of mitochondrial uncoupling protein 2 in space-relevant samples suggests perturbation of the intracellular redox homeostasis, and leaves open opportunities for antioxidant treatment for oxidative stress reduction in harsh environments.

Functional and stimuli-responsive nanofibers with an enhanced surface area/volume ratio provide controlled and triggered drug release with higher efficacy. In this study, chemotherapeutic agent Rose Bengal (RB) (4,5,6,7-tetrachloro-2', 4',5',7'-tetraiodofluoresceindisodium)-loaded water-soluble polyvinyl alcohol (PVA) nanofibers were synthesized by using the electrospinning method. A thin layer of poly(4-vinylpyridine-co-ethylene glycol dimethacrylate) p(4VP-co-EGDMA) was deposited on the RB-loaded nanofibers (PVA-RB) via initiated chemical vapor deposition (iCVD), coating the fiber surfaces to provide controllable solubility and pH response to the nanofibers. The uncoated and [p(4VP-co-EGDMA)-PVA] coated PVA-RB nanofiber mats were studied at different pH values to analyze their degradation and drug release profiles. The coated nanofibers demonstrated high stability at neutral and basic pH values for long incubation durations of 72 h, whereas the uncoated nanofibers dissolved in <2 h. The drug release studies showed that the RB release from coated PVA-RB nanofibers was higher at neutral and basic pH values, and proportional to the pH of the solution, whereas the degradation and RB release rates from the uncoated PVA-RB nanofibers were significantly higher and did not depend on the pH of environment. Further analysis of the release kinetics using the Peppas model showed that while polymer swelling and dissolution were the dominant mechanisms for the uncoated nanofibers, for the coated nanofibers, Fickian diffusion was the dominant release mechanism. The biocompatibility and therapeutic efficiency of the coated PVA-RB nanofibers against brain cancer was investigated on glioblastoma multiforme cancer cells (U87MG). The coated PVA nanofibers were observed to be highly biocompatible, and they significantly stimulated the ROS production in cells, increasing apoptosis. These promising results confirmed the therapeutic activity of the coated PVA-RB nanofibers on brain cancer cells, and encouraged their further evaluation as drug carrier structures in brain cancer treatment.

EDITORIAL article Front. Bioeng. Biotechnol., 30 January 2019Sec. Nanobiotechnology Volume 7 - 2019 | https://doi.org/10.3389/fbioe.2019.00011