Overexpression of miR-4669 Enhances Tumor Aggressiveness and Generates an Immunosuppressive Tumor Microenvironment in Hepatocellular Carcinoma: Its Clinical Value as a Predictive Biomarker.

Accumulating evidence suggests the involvement of tumor-derived exosomes in the development and recurrence of hepatocellular carcinoma (HCC). We previously identified miR-4669 as a highly expressed microRNA in circulating exosomes obtained from patients with post-transplant HCC recurrence. This study aimed to explore how overexpression of miR-4669 affects HCC development and recurrence. The impact of miR-4669 overexpression in Hep3B cells on tumor cell behavior and the tumor microenvironment was evaluated in vitro. In addition, the clinical value of exosomal miR-4669 for the prediction of treatment response to HCC downstaging therapies and following post-transplant HCC recurrence was explored. Overexpression of miR-4669 enhanced migration ability and led to acquired sorafenib resistance with an elevation of sirtuin 1 and long noncoding RNA associated with microvascular invasion. Active release of tumor-derived exosomes and glyceraldehyde 3-phosphate dehydrogenase (GAPDH) contributed to generating an immunosuppressive tumor microenvironment through the induction of M2 macrophage polarization. The retrospective analysis demonstrated the clinical value of exosomal miR-4669 for predicting treatment response to HCC downstaging therapies and for risk assessment of post-transplant HCC recurrence. In summary, the present data demonstrate the impact of exosomal miR-4669 on HCC recurrence through the enhancement of tumor aggressiveness and generation of an immunosuppressive tumor microenvironment.

Hydration Dynamics and the Future of Small-Amplitude AFM Imaging in Air.

Here, we discuss the effects that the dynamics of the hydration layer and other variables, such as the tip radius, have on the availability of imaging regimes in dynamic AFM-including multifrequency AFM. Since small amplitudes are required for high-resolution imaging, we focus on these cases. It is possible to fully immerse a sharp tip under the hydration layer and image with amplitudes similar to or smaller than the height of the hydration layer, i.e., ~1 nm. When mica or HOPG surfaces are only cleaved, molecules adhere to their surfaces, and reaching a thermodynamically stable state for imaging might take hours. During these first hours, different possibilities for imaging emerge and change, implying that these conditions must be considered and reported when imaging.

Sunlight Exposure and Phototherapy: Perspectives for Healthy Aging in an Era of COVID-19.

Most humans depend on sunlight exposure to satisfy their requirements for vitamin D3. However, the destruction of the ozone layer in the past few decades has increased the risk of skin aging and wrinkling caused by excessive exposure to ultraviolet (UV) radiation, which may also promote the risk of skin cancer development. The promotion of public health recommendations to avoid sunlight exposure would reduce the risk of skin cancer, but it would also enhance the risk of vitamin D3 insufficiency/deficiency, which may cause disease development and progression. In addition, the ongoing global COVID-19 pandemic may further reduce sunlight exposure due to stay-at-home policies, resulting in difficulty in active and healthy aging. In this review article, we performed a literature search in PubMed and provided an overview of basic and clinical data regarding the impact of sunlight exposure and vitamin D3 on public health. We also discuss the potential mechanisms and clinical value of phototherapy with a full-spectrum light (notably blue, red, and near-infrared light) as an alternative to sunlight exposure, which may contribute to combating COVID-19 and promoting active and healthy aging in current aged/superaged societies.

Daily full spectrum light exposure prevents food allergy-like allergic diarrhea by modulating vitamin D3 and microbiota composition.

The importance of sun exposure on human health is well recognized, and a recent trend in the avoidance of sun exposure has led to the risk of missing the beneficial effects such as vitamin D3 biogenesis. Vitamin D3 insufficiency is one of the risk factors for the development of food allergies (FAs), and vitamin D3 status controls gut homeostasis by modulating the microbiota. This study aimed to explore the impact of daily full spectrum light exposure (phototherapy) on the pathogenesis of FAs. Phototherapy ameliorated allergic diarrhea and improved FA-associated vitamin D3 insufficiency and dysbiosis. Fecal microbiota transplantation (FMT) of FA donor feces induced allergic diarrhea with OVA-specific IgE elevation in naïve mice. In contrast, FMT of naïve donor feces ameliorated allergic diarrhea in established FA mice, suggesting the involvement of the microbiota composition in FA. Phototherapy is an alternative approach for the prevention of FA-like allergic diarrhea through the modulation of vitamin D3 status and microbiota composition.

Rapid discrimination of chemically distinctive surface terminations in 2D material based heterostructures by direct van der Waals identification.

We demonstrate that surfaces presenting heterogeneous and atomically flat domains can be directly and rapidly discriminated via robust intensive quantifiables by exploiting one-pass noninvasive methods in standard atomic force microscopy (AFM), single ∼2 min passes, or direct force reconstruction, i.e., ∼103 force profiles (∼10 min collection time), allowing data collection, interpretation, and presentation in under 20 min, including experimental AFM preparation and excluding only sample fabrication, in situ and without extra experimental or time load. We employ a misfit SnTiS3 compound as a model system. Such heterostructures can be exploited as multifunctional surface systems and provide multiple support sites with distinguishable chemical, mechanical, or opto-electronic distinct properties. In short, they provide an ideal model system to exemplify how current AFM methods can significantly support material discovery across fields.

Explaining doping in material research (Hf substitution in ZnO films) by directly quantifying the van der Waals force.

Non-monotonic behavior has been observed in the optoelectronic properties of ZnO thin films as doped with Hf (HZO). Here we propose that two competing mechanisms are responsible for such behaviour. Specifically, we propose that provided two crystal orientations dominate film growth, only one of them might be responsible for direct Hf substitution. Nonmonotonic behaviour is expected at once by considering that preferential growth of the crystal that allows for direct Hf substitution is inhibited by Hf concentration in the manufacturing process. This inhibition would also be a thermodynamic consequence of Hf substitution. Maxima in Hf substitution is thus reached at a point where enough crystals exhibit the preferential orientation, and where enough Hf is present on the surface for substitution. Outside this optimum scenario, Hf substitution can only decrease. We interpret the surface phenomena by discussing surface energy and the van der Waals forces as measured experimentally by means of atomic force microscopy.

Insights into graphene wettability transparency by locally probing its surface free energy.

In this work, we study the surface energy of monolayer, bilayer and multilayer graphene coatings, produced through exfoliation of natural graphite flakes and chemical vapor deposition. We employ bimodal atomic force microscopy and micro-Raman spectroscopy for high spatial resolution and large area scanning of force of adhesion on the regions of the graphene/SiO2 surface with different graphene layers. Our measurements show that the interface conditions between graphene and SiO2 dominate the experimentally observed graphene surface energy. This finding sheds new light on the controversy surrounding graphene transparency studies. By separating the surface energy into polar and non-polar interactions, our findings suggest that monolayer graphene is nearly van der Waals opaque but partially transparent (near 60%) to polar interactions, which is further supported by characterizing graphene on the copper surface and two levels of density functional theory simulation. In addition to providing quantitative insight into the surface interactions of complicated graphene coatings, this work demonstrates a new route to nondestructively monitor the interface between graphene and coated substrates.

Direct Measurement of the Magnitude of the van der Waals Interaction of Single and Multilayer Graphene.

Vertical stacking of monolayers via van der Waals (vdW) assembly is an emerging field that opens promising routes toward engineering physical properties of two-dimensional materials. Industrial exploitation of these engineering heterostructures as robust functional materials still requires bounding their measured properties so as to enhance theoretical tractability and assist in experimental designs. Specifically, the short-range attractive vdW forces are responsible for the adhesion of chemically inert components and are recognized to play a dominant role in the functionality of these structures. Here, we reliably quantify the strength of ambient vdW forces in terms of an effective Hamaker coefficient for chemical vapor deposition-grown graphene and show how it scales by a factor of two or three from single to multiple layers on standard supporting surfaces such as copper or silicon oxide. Furthermore, direct measurements on freestanding graphene provide the means to discern the interplay between the vdW potential of graphene and its supporting substrate. Our results demonstrated that the underlying substrates could be controllably exploited to enhance or reduce the vdW force of graphene surfaces. We interpret the physical phenomena in terms of a Lifshitz theory-based analytical model.

The evolution in graphitic surface wettability with first-principles quantum simulations: the counterintuitive role of water.

The surface wettability of graphite has gained a lot of interest in nanotechnology and fundamental studies alike, but the types of adsorptions that dominate its time resolved surface property variations in ambient environment are still elusive. Prediction of the intrinsic surface wettability of graphite from first-principles simulations offers an opportunity to clarify the overall evolution. In this study, by combining experimental temporal Fourier transform infrared spectroscopy, atomic force microscopy (AFM), and static contact angle measurements with density functional theory (DFT)-predicted contact angles and DFT AFM force simulations, we provide conclusive evidence to demonstrate the role played by water adsorption in the evolution of surface properties of aged graphite in ambient air. Moreover, this study has the merit of linking DFT-predicted adhesive energy at the solid/liquid interface and cohesive energy at the liquid/liquid interface with the DFT AFM-predicted force of adhesion through the Young-Dupre equation. This establishes the basis of the quantum surface wettability theory by combining two independent atomic-level quantum physics simulation methodologies.

Discerning the Contribution of Morphology and Chemistry in Wettability Studies.

The wetting behavior of homogeneous systems is now well understood at the macroscopic scale. However, this understanding offers little predictive power regarding wettability when mesoscopic chemical and morphological heterogeneities come into play. The fundamental interest in the effect of heterogeneity on wettability is derived from its high technological relevance in several industries, including the petroleum industry where wettability is recognized as a key determinant of the overall efficiency of the water-flooding-based enhanced oil recovery process. Here, we demonstrate the use of the atomic force microscopy force curve measurements to distinguish the roles of chemistry and morphology in the wetting properties of rock formations, thus providing a clear interpretation and deeper insight into the wetting behavior of heterogeneous formations. Density functional theory calculations further prove the versatility of our approach by establishing benchmarks on ideal surfaces that differ in chemistry and morphology in a predefined manner.

Surface aging investigation by means of an AFM-based methodology and the evolution of conservative nanoscale interactions.

The divergence in physical properties of surfaces exposed to airborne contaminants in the atmosphere has been widely investigated in recent years, but agreement regarding the role that airborne hydrocarbons and water contamination have on surface property evolution remains elusive. Here we investigate the evolution of a freshly grown highly oriented pyrolytic graphite (HOPG) surface exposed to a controlled environment solely containing airborne water contamination, i.e. water vapor. Our approach combines standard electromagnetic spectrum-based spectrometry methods and atomic force microscopy based techniques to provide a holistic view of the surface properties. We provide evidence of the affect that water adsorption kinetics has on surface properties, interpreting time dependent force-distance profiles and force of adhesion maps directly obtained from the standard observables in a bimodal AFM. To demonstrate the generality of our approach we also apply it to aged calcite surfaces, proving its advantages in providing comprehensive transient characterization of surfaces with sufficient spatial resolution.

Water wettability of graphene: interplay between the interfacial water structure and the electronic structure.

Wetting phenomena are ubiquitous and impact a wide range of applications. Simulations so far have largely relied on classical potentials. Here, we report the development of an approach that combines density-functional theory (DFT)-based calculations with classical wetting theory that allows practical but sufficiently accurate determination of the water contact angle (WCA). As a benchmark, we apply the approach to the graphene and graphite surfaces that recently received considerable attention. The results agree with and elucidate the experimental data. For metal-supported graphene where electronic interactions play a major role, we demonstrate that doping of graphene by the metal substrate significantly alters the wettability. In addition to theory, we report new experimental measurements of the WCA and the force of adhesion that corroborate the theoretical results. We demonstrate a correlation between the force of adhesion and WCA, and the use of the atomic force microscope (AFM) technique as an alternative measure for wettability at the nanoscale. The present work not only provides a detailed understanding of the wettability of graphene, including the role of electrons, but also sets the stage for studying the wettability alteration mechanism when sufficiently accurate force fields may not be available.

Therapeutic potential of α-lipoic acid derivative, sodium zinc histidine dithiooctanamide, in a mouse model of allergic rhinitis.

BACKGROUND: Oxidative stress is involved in various diseases, including allergies. Several studies have pointed to the preventive and therapeutic potential of antioxidants in allergic disorders. However, little is known about the immunomodulatory effects of antioxidants in type I hypersensitivity. In this study we aimed to explore the impact of a water-soluble antioxidant and α-lipoic acid derivative, sodium zinc histidine dithiooctanamide (DHL-HisZn), on mast-cell- and T-cell-mediated allergic and immune responses both in vitro and in vivo. METHODS: The therapeutic impact of DHL-HisZn on mast-cell-mediated type I hypersensitivity was evaluated by a mast-cell degranulation assay using bone marrow-derived mast cells and by a mouse model of ovalbumin (OVA)-induced allergic rhinitis. The effect of DHL-HisZn on the proportion of regulatory T cells (Tregs) was evaluated using flow cytometry. RESULTS: During the course of OVA-induced allergic rhinitis in mice, serum nitrate was elevated, suggesting the involvement of oxidative stress in allergic responses. DHL-HisZn not only suppressed mast-cell degranulation but also ameliorated OVA-induced nasal hypersensitivity, with significant suppression of serum nitrate. DHL-HisZn treatment significantly suppressed OVA-specific immunoglobulin E (IgE) but enhanced OVA-specific IgG2a in OVA-sensitized and nasal-challenged mice. Furthermore, DHL-HisZn treatment suppressed interleukin-17 production in OVA-stimulated splenocytes. Finally, we demonstrated the induction of Tregs by DHL-HisZn in concanavalin A blasts. CONCLUSIONS: These findings suggest that DHL-HisZn may regulate mast-cell-, T-helper 2 (Th2)-, and Th17-mediated allergic and immune responses by induction of Tregs.

Multifrequency AFM: from origins to convergence.

Since the inception of the atomic force microscope (AFM) in 1986, influential papers have been presented by the community and tremendous advances have been reported. Being able to routinely image conductive and non-conductive surfaces in air, liquid and vacuum environments with nanoscale, and sometimes atomic, resolution, the AFM has long been perceived by many as the instrument to unlock the nanoscale. From exploiting a basic form of Hooke's law to interpret AFM data to interpreting a seeming zoo of maps in the more advanced multifrequency methods however, an inflection point has been reached. Here, we discuss this evolution, from the fundamental dilemmas that arose in the beginning, to the exploitation of computer sciences, from machine learning to big data, hoping to guide the newcomer and inspire the experimenter.

Hepatic miR-301a as a Liver Transplant Rejection Biomarker? And Its Role for Interleukin-6 Production in Hepatocytes.

Acute rejection (AR) of liver transplantation remains a formidable challenge for diagnostic medicine and biomarker discovery. We characterized AR-related microRNAs (miRNAs) and the underlying AR mechanisms in liver transplantation. Using a rat model of orthotopic liver transplantation (OLT) as well as microarrays, we compared the miRNA expression profiles between naive and AR livers on day 7 after OLT with short- (<14 days, donor Dark Agouti [DA] liver into Lewis [LEW] recipient) and long-term (>60 days, donor DA liver into Piebald Virol Glaxo [PVG] recipient) survival fates. The microarray analysis revealed that the levels of miR-301a in the lethal AR livers were significantly higher than in naive and tolerogenic AR livers. The reduced expression of miR-301a in inflamed livers suggested a difference between AR and inflammation in terms of miR-301a-mediated molecular events. Overexpression of hepatic miR-301a induced IL-6 production in rat primary hepatocytes. Hepatocytes overexpressing miR-301a were capable of transferring miR-301a to cocultured splenocytes through exosomes. These splenocytes then showed overexpression of miR-301a and downregulation of protein inhibitor of activated STAT3 (PIAS3) expression, resulting in the induction of T helper 17 cell differentiation. In conclusion, this report raises the possibility that hepatic miR-301a might potentially prove value as a biomarker of liver transplant rejection. We call for future research on this molecular target and the attendant pathways as liver transplant rejection and its early diagnosis continue to be veritable healthcare challenges.

DHL-HisZn, a novel antioxidant, enhances adipogenic differentiation and antioxidative response in adipose-derived stem cells.

Adipose-derived stem cells (ASCs) are multipotent progenitor cells that have the capacity to differentiate into specific mesenchymal cell lineages including adipocytes in response to environmental cues. Dysfunctional adipose tissue, rather than an excess of adipose tissue, has been proposed as a key factor in the pathogenesis of obesity-related diseases. The insulin-sensitizing effects of antidiabetic drugs are mediated by activation of peroxisome proliferator-activated receptor gamma (PPARγ). Here, we investigated the effects of sodium zinc histidine dithiooctanamide (DHL-HisZn), a strong antioxidant, on PPARγ activation, adipocyte differentiation and insulin sensitivity. Additionally, the effects of DHL-HisZn on cellular antioxidant response and inflammatory cytokine production were also evaluated. In ASCs, DHL-HisZn enhanced adipocyte differentiation and PPARγ expression in a dose-dependent manner. DHL-HisZn also increased the relative abundance of insulin-responsive glucose transporter 4 (GLUT4) and adiponectin mRNA. Furthermore, DHL-HisZn upregulated PPARγ downstream target gene expression. In addition, treatment with DHL-HisZn upregulated mRNA levels of endogenous antioxidants, such as glucose-6-phosphate dehydrogenase (G6PD), superoxide dismutase 2 (SOD2), catalase (CAT) and glutathione reductase (GR). DHL-HisZn treatment enhanced insulin signaling and inhibited NF-κB activation, which subsequently suppressed inflammatory cytokine IL-6 expression. Our results indicate that DHL-HisZn enhances insulin sensitivity in adipocytes by increasing the expression of GLUT4 and IRS-1 via the activation of PPARγ and improving the antioxidant response during adipogenic differentiation. Therefore, DHL-HisZn may have the capability to reduce insulin resistance.

The Mendeleev-Meyer force project.

Here we present the Mendeleev-Meyer Force Project which aims at tabulating all materials and substances in a fashion similar to the periodic table. The goal is to group and tabulate substances using nanoscale force footprints rather than atomic number or electronic configuration as in the periodic table. The process is divided into: (1) acquiring nanoscale force data from materials, (2) parameterizing the raw data into standardized input features to generate a library, (3) feeding the standardized library into an algorithm to generate, enhance or exploit a model to identify a material or property. We propose producing databases mimicking the Materials Genome Initiative, the Medical Literature Analysis and Retrieval System Online (MEDLARS) or the PRoteomics IDEntifications database (PRIDE) and making these searchable online via search engines mimicking Pubmed or the PRIDE web interface. A prototype exploiting deep learning algorithms, i.e. multilayer neural networks, is presented.

Integrated Nano- and Macroscale Investigation of Photoinduced Hydrophilicity in TiO2 Thin Films.

The hydrophilicity of titanium dioxide has been investigated for films, deposited on glass by e-beam evaporation, being exposed to UV radiation and subjected to thermal annealing. The wettability alteration has been showed to depend upon both treatments, and insights into how to introduce more stable hydrophilicity into these films have been presented for the sake of boosting their commercial value. Observations from multiple length scales to assess the wetting behavior of as-deposited and high-temperature annealed samples were assessed through macroscopic measurements, i.e., water contact angle measurements, showing that the annealed crystalline samples, treated at 500 °C, are much more hydrophilic (SCA ≈ 20°) than as-deposited TiO2 films (SCA ≈ 90°), and the nanoscopic experiments performed by amplitude modulation (AM) atomic force microscopy (AFM) indicated that this increased hydrophilicity is related to an enhanced adhesion force and surface energy, resulting in the partial crystallization of TiO2 and the consequent formation of crystals on its surface rather than being related to morphologic differences. XRD and Raman measurements have highlighted that the crystallinity of the TiO2 film is crucial in determining its hydrophilicity, in good agreement with the AFM study. The results also indicated that, after irradiation, the samples treated at 500 °C preserve their hydrophilicity for a significant time compared to previous studies.

Divergent surface properties of multidimensional sp (2) carbon allotropes: the effect of aging phenomena.

Despite the current interest in the scientific community in exploiting divergent surface properties of graphitic carbon allotropes, conclusive differentiation remains elusive even when dealing with parameters as fundamental as adhesion. Here, we set out to provide conclusive experimental evidence on the time evolution of the surface properties of highly oriented pyrolytic graphite (HOPG), graphene monolayer (GML) and multiwalled carbon nanotubes (MWCNTs) as we expose these materials to airborne contaminants, by providing (1) statistically significant results based on large datasets consisting of thousands of force measurements, and (2) errors sufficiently self-consistent to treat the comparison between datasets in atomic force microscopy (AFM) measurements. We first consider HOPG as a model system and then employ our results to draw conclusions from the GML and MWCNT samples. We find that the surface properties of aged HOPG are indistinguishable from those of aged GML and MWCNT, while being distinct from those of cleaved HOPG. Herein, we provide a sufficient body of evidence to disregard any divergence in surface properties for multidimensional sp (2) carbon allotropes that undergo similar aging processes.

Systematic Multidimensional Quantification of Nanoscale Systems From Bimodal Atomic Force Microscopy Data.

Here we explore the raw parameter space in air in bimodal atomic force microscopy (AFM) in order to enhance resolution, provide multiparameter maps, and produce suitable transformations that lead to physically intuitive maps general enough to be recognized by the broader community, i.e., stiffness, Hamaker constant, and adhesion force. We further consider model free transforms to enhance the raw parameter space in the form of alternative and more intelligible contrast maps. We employ highly oriented pyrolytic graphite, calcite, polypropylene, and dsDNA on mica to demonstrate a systematic form of parameter expansion. The proposed methodology to enhance and interpret a larger parameter space introduces a methodology to tractable multidimensional AFM from raw bimodal AFM maps.