Therapeutic Effects of Hypoxic and Pro-Inflammatory Priming of Mesenchymal Stem Cell-Derived Extracellular Vesicles in Inflammatory Arthritis

Mesenchymal stem cells (MSCs) immunomodulate inflammatory responses through paracrine signalling, including via secretion of extracellular vesicles (EVs) in the cell secretome. We evaluated the therapeutic potential of MSCs-derived small EVs in an antigen-induced model of arthritis (AIA). EVs isolated from MSCs cultured normoxically (21% O₂, 5% CO₂), hypoxically (2% O₂, 5% CO₂) or with a pro-inflammatory cytokine cocktail were applied into the AIA model. Disease pathology was assessed post-arthritis induction through swelling and histopathological analysis of synovial joint structure. Activated CD4+ T cells from healthy mice were cultured with EVs or MSCs to assess deactivation capabilities prior to application of standard EVs in vivo to assess T cell polarisation within the immune response to AIA. All EVs treatments reduced knee-joint swelling whilst only normoxic and pro-inflammatory primed EVs improved histopathological outcomes. In vitro culture with EVs did not achieve T cell deactivation. Polarisation towards CD4+ helper cells expressing IL17a (Th17) was reduced when normoxic and hypoxic EV treatments were applied in vitro. Normoxic EVs applied into the AIA model reduced Th17 polarisation and improved Regulatory T cell (Treg):Th17 homeostatic balance. Normoxic EVs present the optimal strategy for broad therapeutic benefit. EVs present an effective novel technology with the potential for cell-free therapeutic translation.     

Trabecular Bone Parameters,TIMP-2, MMP-8, MMP-13, VEGF Expression and Immunolocalization in Bone and Cartilage in Newborn Offspring Prenatally Exposed to Fumonisins

Fumonisins are protein serine/threonine phosphatase inhibitors and potent inhibitors of sphingosine N-acyltransferase (ceramide synthase) disrupting de novo sphingolipid biosynthesis. The experiment was conducted to evaluate the effects of fumonisins (FB) exposure from the 7th day of pregnancy to parturition on offspring bone development. The rats were randomly allocated to either a control group (n = 6), not treated with FBs, or to one of the two groups intoxicated with FBs (either at 60 mg FB/kg b.w. or at 90 mg FB/kg b.w. Numerous negative, offspring sex-dependent effects of maternal FB exposure were observed with regards to the histomorphometry of trabecular bone. These effects were due to FB-inducted alterations in bone metabolism, as indicated by changes in the expression of selected proteins involved in bone development: tissue inhibitor of metalloproteinases 2 (TIMP-2), matrix metalloproteinase 8 (MMP-8), matrix metalloproteinase 13 (MMP-13), and vascular endothelial growth factor (VEGF). The immunolocalization of MMPs and TIMP-2 was performed in trabecular and compact bone, as well as articular and growth plate cartilages. Based on the results, it can be concluded that the exposure of pregnant dams to FB negatively affected the expression of certain proteins responsible for bone matrix degradation in newborns prenatally exposed to FB in a dose- and sex-dependent manner.     

The Effects of Endogenous Non-Peptide Molecule Isatin and Hydrogen Peroxide on Proteomic Profiling of Rat Brain Amyloid-β Binding Proteins: Relevance to Alzheimer’s Disease?

The amyloid-β peptide is considered as a key player in the development and progression of Alzheimer’s disease (AD). Although good evidence exists that amyloid-β accumulates inside cells, intracellular brain amyloid-binding proteins remain poorly characterized. Proteomic profiling of rat brain homogenates, performed in this study, resulted in identification of 89 individual intracellular amyloid-binding proteins, and approximately 25% of them were proteins that we had previously identified as specifically binding to isatin, an endogenous neuroprotector molecule. A significant proportion of the amyloid-binding proteins (more than 30%) are differentially expressed or altered/oxidatively modified in AD patients. Incubation of brain homogenates with 70 µM hydrogen peroxide significantly influenced the profile of amyloid-β binding proteins and 0.1 mM isatin decreased the number of identified amyloid-β binding proteins both in control and hydrogen peroxide treated brain homogenates. The effects of hydrogen peroxide and isatin have been confirmed in optical biosensor experiments with purified glyceraldehyde-3-phosphate dehydrogenase, one of the known crucial amyloid-β binding proteins (also identified in this study). Data obtained suggest that isatin protects crucial intracellular protein targets against amyloid binding, and possibly favors intracellular degradation of this protein via preventing formation of amyloid-β oligomers described in the literature for some isatin derivatives.     

Structural and Magnetoelectric Behavior of Lanthanum Manganite‐Based Multiferroic Heterostructures

The effect of fabrication method on the structure of (100 ? x) wt% BaTiO₃ + x wt% La_0.7Ba_0.3MnO₃ (BT + BLM) and (100 ? x) wt% Na, Bi, Sr‐doped PZT + x wt% La_0.65Pb_0.35MnO₃ (PZTNB‐1 + PLM) magnetoelectric ceramics was studied. Profound interdiffusion of two interacting phases occurs in nearly all cases. The BT + BLM and PZTNB‐1 + PLM ceramics exhibit low piezoelectric parameters even with small manganite contents (10–20 wt%). The increased content of the magnetostrictive phase complicates the polarization process due to the high conductivity of La_0.7Ba_0.3MnO₃ and La_0.65Pb_0.35MnO₃. Doping of BaTiO₃ and PZTNB‐1 with small additions of manganite components affects piezoelectric properties, thereby lowering efficiency of the resulting material.     

Characterization of defects in titanium created by hydrogen charging

In the present work positron annihilation spectroscopy was employed for investigation of defects created in titanium by hydrogen loading. Pure titanium samples were firstly annealed to remove dislocations introduced by cutting and polishing. Subsequently the samples were loaded with hydrogen up to various hydrogen concentrations. Ti samples with different microstructures were compared: (i) conventional coarse grained sample, (ii) ultra fine grained material with microstructure refined by severe plastic deformation. Hydrogen gas loading of coarse grained and ultra fine grained samples was performed at hydrogen gas pressure of 103 bar and temperature of 150 °C. This resulted in formation of δ-TiH_x phase in Ti matrix. The hydrogen content absorbed in the samples was determined by thermogravimetric analysis. The phase composition of hydrogen-loaded samples was characterized by X-ray diffraction. Hydrogen loading introduced vacancies which agglomerated in the sample into small vacancy clusters. In addition to vacancies, dislocations were created by α-Ti → δ-TiH_x phase transition. Differential thermal analysis revealed that hydrogen is trapped at several kinds of traps characterized by different binding energies. The release of hydrogen from these traps precedes the decomposition of the δ-TiH_x phase.     

Cryostructured and Crosslinked Viable Cells Forming Monoliths Suitable for Bioreactor Applications

Applications of immobilized biocatalysts in both research and industry require highly active catalysts, preferably at a low cost. In this study, cryogels with high catalyst density were produced through cryostructuration of whole Escherichia coli (E.coli) cells. Prepared cryogels are macroporous materials composed of metabolically active cells crosslinked to each other via polymeric structures. Different macromolecular reagents: oxidized dextran (OxDex), polyvinyl alcohol (PVA) and polyethyleneimine (PEI), the two latter activated with glutaraldehyde (GTA) have been synthesized. Prepared polymers were tested as effective and mild crosslinkers for cells during the cryostructuration procedure. Combination of the two synthetic polymers: PEI+GTA and PVA+GTA was found most suitable for formation of macroporous and stable structures from cells without any toxic effect on them. About 90 % of β-glucosidase activity in cells was retained after crosslinking with a combination of synthetic polymers, whereas E. coli crosslinked using GTA showed complete loss of activity. Preserved viability of cells in cryogel offers possibility to induce protein expression in cells after crosslinking. For β-glucosidase induction post immobilization yielded 50 % activity of that from cells induced in free form before cryo-structurization. The results of the post immobilization studies indicate an interesting potential for handling very sensitive enzymes.     

Gold nanoparticles into Ti1−xZnxO2 films: Synthesis,structure and application

The gold particles of certain size were incorporated into Ti_1−xZn_xO₂ films by sol–gel method. The synthesis conditions predetermine the size and shape of gold nanoparticles, which were monitored by the absorption spectra and SEM images. The results of Raman spectra measurements indicate that Au nanoparticles inhibit the grain growth of anatase within the film. The photocatalytic activity of Au/Ti_1−xZn_xO₂ films in the degradation of tetracycline hydrochloride depends on the sizes of Au particles.