Ex vivo expansion of human circulating myogenic progenitors on cluster-assembled nanostructured TiO2

Environmental stressor assessment of hydrocarbonoclastic bacteria biofilms from a marine oil spill

The environmental and economic impact of an oil spill can be significant. Biotechnologies applied during a marine oil spill involve bioaugmentation with immobilised or encapsulated indigenous hydrocarbonoclastic species selected under laboratory conditions to improve degradation rates. The environmental factors that act as stressors and impact the effectiveness of hydrocarbon removal are one of the challenges associated with these applications. Understanding how native microbes react to environmental stresses is necessary for effective bioaugmentation. Herein, Micrococcus luteus and M. yunnanensis isolated from a marine oil spill mooring system showed hydrocarbonoclastic activity on Maya crude oil in a short time by means of total petroleum hydrocarbons (TPH) at 144 h: M. luteus up to 98.79 % and M. yunnanensis 97.77 % removal. The assessment of Micrococcus biofilms at different temperature (30 °C and 50 °C), pH (5, 6, 7, 8, 9), salinity (30, 50, 60, 70, 80 g/L), and crude oil concentration (1, 5, 15, 25, 35 %) showed different response to the stressors depending on the strain. According to response surface analysis, the main effect was temperature > salinity > hydrocarbon concentration. The hydrocarbonoclastic biofilm architecture was characterised using scanning electron microscopy (SEM) and atomic force microscopy (AFM). Subtle but significant differences were observed: pili in M. luteus by SEM and the topographical differences measured by AFM Power Spectral Density (PSD) analysis, roughness was higher in M. luteus than in M. yunnanensis. In all three domains of life, the Universal Stress Protein (Usp) is crucial for stress adaptation. Herein, the uspA gene expression was analysed in Micrococcus biofilm under environmental stressors. The uspA expression increased up to 2.5-fold in M. luteus biofilms at 30 °C, and 1.3-fold at 50 °C. The highest uspA expression was recorded in M. yunnanensis biofilms at 50 °C with 2.5 and 3-fold with salinities of 50, 60, and 80 g/L at hydrocarbon concentrations of 15, 25, and 35 %. M. yunnanensis biofilms showed greater resilience than M. luteus biofilms when exposed to harsh environmental stressors. M. yunnanensis biofilms were thicker than M. luteus biofilms. Both biofilm responses to environmental stressors through uspA gene expression were consistent with the behaviours observed in the response surface analyses. The uspA gene is a suitable biomarker for assessing environmental stressors of potential microorganisms for bioremediation of marine oil spills and for biosensing the ecophysiological status of native microbiota in a marine petroleum environment.

Cluster-Assembled Nanoporous Super-Hydrophilic Smart Surfaces for On-Target Capturing and Processing of Biological Samples for Multi-Dimensional MALDI-MS

Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) on cluster-assembled super-hydrophilic nanoporous titania films deposited on hydrophobic conductive-polymer substrates feature a unique combination of surface properties that significantly improve the possibilities of capturing and processing biological samples before and during the MALDI-MS analysis without changing the selected sample target (multi-dimensional MALDI-MS). In contrast to pure hydrophobic surfaces, such films promote a remarkable biologically active film porosity at the nanoscale due to the soft assembling of ultrafine atomic clusters. This unique combination of nanoscale porosity and super-hydrophilicity provides room for effective sample capturing, while the hydrophilic-hydrophobic discontinuity at the border of the dot-patterned film acts as a wettability-driven containment for sample/reagent droplets. In the present work, we evaluate the performance of such advanced surface engineered reactive containments for their benefit in protein sample processing and characterization. We shortly discuss the advantages resulting from the introduction of the described chips in the MALDI-MS workflow in the healthcare/clinical context and in MALDI-MS bioimaging (MALDI-MSI).

Multifunctional Polypyrrole-Coated Mesoporous TiO2 Nanocomposites for Photothermal, Sonodynamic, and Chemotherapeutic Treatments and Dual-Modal Ultrasound/Photoacoustic Imaging of Tumors

TiO₂ nanoparticles have emerged as satisfactory sonosensitizers in sonodynamic therapy over the years, but shortcomings such as poor drug loading capability and inadequate techniques to construct suitable TiO₂ nanoparticles, limit their broader applications. Hence, in this paper, versatile nanocomposites that combine mesoporous TiO₂ nanoparticles (mTiO₂ s) with the promising photothermal material, polypyrrole (PPY) to exert synergistic therapeutic effects on tumors are fabricated. The PPY-coated mesoporous TiO₂ nanocomposites (mTiO₂ @PPYs) act as drug delivery vehicles and ultrasonically activated sonosensitizers as well as photothermal agents. Besides, mTiO₂ @PPY may have potential as an ultrasound/photoacoustic (US/PA) imaging contrast agent. The mTiO₂ @PPY shows a favorable drug loading and good photothermal conversion ability. Moreover, intracellular reactive oxygen species generation is verified. The in vitro cell experiments on HepG2 and 4T1 cells demonstrate that honokiol (HNK)-loaded mTiO₂ @PPY has satisfactory cytotoxicity under laser and US irradiation, and the results are further validated by animal experiments. The ability of mTiO₂ @PPY as a contrast agent for US and PA imaging is investigated both in vitro and in vivo. The results indicate that mTiO₂ @PPY-HNK has multitherapeutic effects and bimodal imaging property, which shows great prospect as a novel nanosystem in antitumor applications.

Autologous intramuscular transplantation of engineered satellite cells induces exosome-mediated systemic expression of Fukutin-related protein and rescues disease phenotype in a murine model of limb-girdle muscular dystrophy type 2I

α-Dystroglycanopathies are a group of muscular dystrophies characterized by α-DG hypoglycosylation and reduced extracellular ligand-binding affinity. Among other genes involved in the α-DG glycosylation process, fukutin related protein (FKRP) gene mutations generate a wide range of pathologies from mild limb girdle muscular dystrophy 2I (LGMD2I), severe congenital muscular dystrophy 1C (MDC1C), to Walker-Warburg Syndrome and Muscle-Eye-Brain disease. FKRP gene encodes for a glycosyltransferase that in vivo transfers a ribitol phosphate group from a CDP –ribitol present in muscles to α-DG, while in vitro it can be secreted as monomer of 60kDa. Consistently, new evidences reported glycosyltransferases in the blood, freely circulating or wrapped within vesicles. Although the physiological function of blood stream glycosyltransferases remains unclear, they are likely released from blood borne or distant cells. Thus, we hypothesized that freely or wrapped FKRP might circulate as an extracellular glycosyltransferase, able to exert a “glycan remodelling” process, even at distal compartments. Interestingly, we firstly demonstrated a successful transduction of MDC1C blood-derived CD133+ cells and FKRP L276I^KI mouse derived satellite cells by a lentiviral vector expressing the wild-type of human FKRP gene. Moreover, we showed that LV-FKRP cells were driven to release exosomes carrying FKRP. Similarly, we observed the presence of FKRP positive exosomes in the plasma of FKRP L276I^KI mice intramuscularly injected with engineered satellite cells. The distribution of FKRP protein boosted by exosomes determined its restoration within muscle tissues, an overall recovery of α-DG glycosylation and improved muscle strength, suggesting a systemic supply of FKRP protein acting as glycosyltransferase.

Skeletal Muscle Regenerative Potential of Human MuStem Cells following Transplantation into Injured Mice Muscle

After intra-arterial delivery in the dystrophic dog, allogeneic muscle-derived stem cells, termed MuStem cells, contribute to long-term stabilization of the clinical status and preservation of the muscle regenerative process. However, it remains unknown whether the human counterpart could be identified, considering recent demonstrations of divergent features between species for several somatic stem cells. Here, we report that MuStem cells reside in human skeletal muscle and display a long-term ability to proliferate, allowing generation of a clinically relevant amount of cells. Cultured human MuStem (hMuStem) cells do not express hematopoietic, endothelial, or myo-endothelial cell markers and reproducibly correspond to a population of early myogenic-committed progenitors with a perivascular/mesenchymal phenotypic signature, revealing a blood vessel wall origin. Importantly, they exhibit both myogenesis in vitro and skeletal muscle regeneration after intramuscular delivery into immunodeficient host mice. Together, our findings provide new insights supporting the notion that hMuStem cells could represent an interesting therapeutic candidate for dystrophic patients.

Quantitative Control of Protein and Cell Interaction with Nanostructured Surfaces by Cluster Assembling

The development of smart prosthetics, scaffolds, and biomaterials for tissue engineering and organ-on-a-chip devices heavily depends on the understanding and control of biotic/abiotic interfaces. In recent years, the nanometer scale emerged as the predominant dimension for processes impacting on protein adsorption and cellular responses on surfaces. In this context, the extracellular matrix (ECM) can be seen as the prototype for an intricate natural structure assembled by nanoscale building blocks forming highly variable nanoscale configurations, dictating cellular behavior and fate. How exactly the ECM nanotopography influences mechanotransduction, that is, the cellular capacity to convert information received from the ECM into appropriate responses, remains partially understood due to the complexity of the involved biological structures, limiting also the attempts to artificially reproduce the nanoscale complexity of the ECM. In this Account, we describe and discuss our strategies for the development of an efficient and large-scale bottom-up approach to fabricate surfaces with multiscale controlled disorder as substrates to study quantitatively the effect of nanoscale topography on biological entities. Our method is based on the use of supersonic cluster beam deposition (SCBD) to assemble, on a substrate, neutral clusters produced in the gas phase and accelerated by a supersonic expansion. The assembling of clusters in the ballistic deposition regime follows simple scaling laws, allowing the quantitative control of surface roughness and asperity layout over large areas. Due to their biocompatibility, we focused on transition metal oxide nanostructured surfaces assembled by titania and zirconia clusters. We demonstrated the engineering of structural and functional properties of the cluster-assembled surfaces with high relevance for interactions at the biotic/abiotic interface. We observed that isoelectric point and wettability, crucial parameters for the adhesion of biological entities on surfaces, are strongly influenced and controlled by the nanoscale roughness. By developing a high-throughput method (protein surface interaction microarray, PSIM), we characterized quantitatively the capacity of the nanostructured surfaces to adsorb proteins, showing that with increasing roughness the adsorption rises beyond what could be expected by the increase in specific area, paralleled by an almost linear decrease in protein binding affinity. We also determined that the spatial layout of the surface asperities effectively perceived by the cells mimics at the nanoscale the topographical ECM characteristics. The interaction with these features consequently regulates parameters significant for cell adhesion and mechanotransductive signaling, such as integrin clustering, focal adhesion maturation, and the correlated cellular mechanobiology, eventually impacting the cellular program and differentiation, as we specifically showed for neuronal cells.

Contributions of muscle-resident progenitor cells to homeostasis and disease

Adult skeletal muscle maintains a homeostatic state with modest levels of cellular turnover, unlike the skin or blood. However, the muscle is highly sensitive to tissue injury, which unleashes a cascade of regenerative and inflammatory processes. Muscle regeneration involves cross-talk between numerous cytokine signaling axes, and the coordinated activity of multiple muscle-resident and circulating progenitor populations. Satellite cells, closely associated with myofibers, are established as the canonical muscle stem cell, with self-renewal and myofiber-regenerating capacity. However, a heterogeneous group of mesenchymal progenitor cells residing within the muscle interstitium are also highly responsive to muscle injury and exhibit varying degrees of regenerative potential. These cells interact with satellite cells via direct and indirect mechanisms to regulate regeneration or repair. We describe the known phylogenetic and functional relationships of the multiple progenitor populations residing within skeletal muscle, their putative roles in the coordination of injury repair, and their possible contributions to health and disease.

Potential application of functional porous TiO2 nanoparticles in light-controlled drug release and targeted drug delivery

Novel multifunctional porous titanium dioxide (TiO2) nanoparticles modified with polyethylenimine (PEI) were developed to explore the feasibility of exploiting the photocatalytic property of titanium dioxide to achieve ultraviolet (UV) light triggered drug release. Additionally, in order to further realize targeting delivery, folic acid, which chemically conjugated to the surface of the functionalized multifunctional porous TiO2 nanoparticles through amide linkage with free amine groups of PEI, was used as a cancer-targeting agent to effectively promote cancer-cell-specific uptake through receptor-mediated endocytosis. And a typical poorly water-soluble anti-cancer drug, paclitaxel, was encapsulated in multifunctional porous TiO2 nanoparticles. The PEI on the surface of multifunctional porous TiO2 nanoparticles could effectively block the channel to prevent premature drug release, thus providing enough circulation time to target cancer cells. Following UV light radiation, PEI molecules on the surface were cut off by the free radicals (OH˙ and O2-) that TiO2 produced, and then the drug loaded in the carrier was released rapidly into the cytoplasm. Importantly, the amount of drug released from multifunctional porous TiO2 nanoparticles can be regulated by the UV-light radiation time to further control the anti-cancer effect. This multifunctional porous TiO2 nanoparticle exhibits a combination of stimuli-triggered drug release and cancer cell targeting. The authors believe that the present study will provide important information for the use of porous TiO2 nanomaterials in light-controlled drug release and targeted therapy.

Human skeletal muscle-derived CD133(+) cells form functional satellite cells after intramuscular transplantation in immunodeficient host mice

Stem cell therapy is a promising strategy for treatment of muscular dystrophies. In addition to muscle fiber formation, reconstitution of functional stem cell pool by donor cells is vital for long-term treatment. We show here that some CD133(+) cells within human muscle are located underneath the basal lamina of muscle fibers, in the position of the muscle satellite cell. Cultured hCD133(+) cells are heterogeneous and multipotent, capable of forming myotubes and reserve satellite cells in vitro. They contribute to extensive muscle regeneration and satellite cell formation following intramuscular transplantation into irradiated and cryodamaged tibialis anterior muscles of immunodeficient Rag2-/γ chain-/C5-mice. Some donor-derived satellite cells expressed the myogenic regulatory factor MyoD, indicating that they were activated. In addition, when transplanted host muscles were reinjured, there was significantly more newly-regenerated muscle fibers of donor origin in treated than in control, nonreinjured muscles, indicating that hCD133(+) cells had given rise to functional muscle stem cells, which were able to activate in response to injury and contribute to a further round of muscle regeneration. Our findings provide new evidence for the location and characterization of hCD133(+) cells, and highlight that these cells are highly suitable for future clinical application.

Nitric oxide synthase mediates PC12 differentiation induced by the surface topography of nanostructured TiO2

Background

Substrate nanoscale topography influences cell proliferation and differentiation through mechanisms that are at present poorly understood. In particular the molecular mechanism through which cells 'sense’ and adapt to the substrate and activate specific intracellular signals, influencing cells survival and behavior, remains to be clarified.

Results

To characterize these processes at the molecular level we studied the differentiation of PC12 cells on nanostructured TiO₂ films obtained by supersonic cluster beam deposition.

Our findings indicate that, in PC12 cells grown without Nerve Growth Factor (NGF), the roughness of nanostructured TiO₂ triggers neuritogenesis by activating the expression of nitric oxide synthase (NOS) and the phospho-extracellular signal-regulated kinase 1/2 (pERK1/2) signaling. Differentiation is associated with an increase in protein nitration as observed in PC12 cells grown on flat surfaces in the presence of NGF. We demonstrate that cell differentiation and protein nitration induced by topography are not specific for PC12 cells but can be regarded as generalized effects produced by the substrate on different neuronal-like cell types, as shown by growing the human neuroblastoma SH-SY5Y cell line on nanostructured TiO₂.

Conclusion

Our data provide the evidence that the nitric oxide (NO) signal cascade is involved in the differentiation process induced by nanotopography, adding new information on the mechanism and proteins involved in the neuritogenesis triggered by the surface properties.

Quantitative characterization of the influence of the nanoscale morphology of nanostructured surfaces on bacterial adhesion and biofilm formation

Bacterial infection of implants and prosthetic devices is one of the most common causes of implant failure. The nanostructured surface of biocompatible materials strongly influences the adhesion and proliferation of mammalian cells on solid substrates. The observation of this phenomenon has led to an increased effort to develop new strategies to prevent bacterial adhesion and biofilm formation, primarily through nanoengineering the topology of the materials used in implantable devices. While several studies have demonstrated the influence of nanoscale surface morphology on prokaryotic cell attachment, none have provided a quantitative understanding of this phenomenon. Using supersonic cluster beam deposition, we produced nanostructured titania thin films with controlled and reproducible nanoscale morphology respectively. We characterized the surface morphology; composition and wettability by means of atomic force microscopy, X-ray photoemission spectroscopy and contact angle measurements. We studied how protein adsorption is influenced by the physico-chemical surface parameters. Lastly, we characterized Escherichia coli and Staphylococcus aureus adhesion on nanostructured titania surfaces. Our results show that the increase in surface pore aspect ratio and volume, related to the increase of surface roughness, improves protein adsorption, which in turn downplays bacterial adhesion and biofilm formation. As roughness increases up to about 20 nm, bacterial adhesion and biofilm formation are enhanced; the further increase of roughness causes a significant decrease of bacterial adhesion and inhibits biofilm formation. We interpret the observed trend in bacterial adhesion as the combined effect of passivation and flattening effects induced by morphology-dependent protein adsorption. Our findings demonstrate that bacterial adhesion and biofilm formation on nanostructured titanium oxide surfaces are significantly influenced by nanoscale morphological features. The quantitative information, provided by this study about the relation between surface nanoscale morphology and bacterial adhesion points towards the rational design of implant surfaces that control or inhibit bacterial adhesion and biofilm formation.

Stem cell-biomaterial interactions for regenerative medicine

The synergism of stem cell biology and biomaterial technology promises to have a profound impact on stem-cell-based clinical applications for tissue regeneration. Biomaterials development is rapidly advancing to display properties that, in a precise and physiological fashion, could drive stem-cell fate both in vitro and in vivo. Thus, the design of novel materials is trying to recapitulate the molecular events involved in the production, clearance and interaction of molecules within tissue in pathologic conditions and regeneration of tissue/organs. In this review we will report on the challenges behind translating stem cell biology and biomaterial innovations into novel clinical therapeutic applications for tissue and organ replacements (graphical abstract).