PLA and PBAT-based electrospun fibers functionalized with antibacterial bio-based polymers

Antimicrobial fibers based on biodegradable polymers, poly(lactic acid) (PLA), and poly(butylene adipate-co-terephthalate) (PBAT) are prepared by electrospinning. For this purpose, a biodegradable/bio-based polyitaconate containing azoles groups (PTTI) is incorporated at 10 wt.% into the electrospinning formulations. The resulting fibers functionalized with azole moieties are uniform and free of beads. Then, the accessible azole groups are subjected to N-alkylation, treatment that provides cationic azolium groups with antibacterial activity at the surface of fibers. The positive charge density, roughness, and wettability of the cationic fibers are evaluated and compared with flat films. It is confirmed that these parameters exert an important effect on the antimicrobial properties, as well as the length of the alkylating agent and the hydrophobicity of the matrix. The quaternized PLA/PTTI fibers exhibit the highest efficiency against the tested bacteria, yielding a 4-Log reduction against S. aureus and 1.7-Log against MRSA. Then, biocompatibility and bioactivity of the fibers are evaluated in terms of adhesion, morphology and viability of fibroblasts. The results show no cytotoxic effect of the samples, however, a cytostatic effect is appreciated, which is ascribed to the strong electrostatic interactions between the positive charge at the fiber surface and the negative charge of the cell membranes

The role of MTHFR polymorphisms in the risk of lipedema

Objective: This study examines the role of MTHFR gene polymorphism (rs1801133) in women with lipedema (LIPPY) body composition parameters compared to a control group (CTRL). Subjects and methods: We carried out a study on a sample of 45 LIPPY and 50 women as a CTRL. Body composition parameters were examined by Dual-energy X-ray Absorptiometry (DXA). A genetic test was performed for the MTHFR polymorphism (rs1801133, 677C>T) using a saliva sample for LIPPY and CTRL groups. Mann-Whitney tests evaluated statistically significant differences between four groups (carriers and non-carriers of the MTHFR polymorphism for LIPPY and CTRL groups) on anthropometric/body composition parameters to identify patterns. Results: LIPPY showed significantly higher (p<0.05) anthropometric parameters (weight, BMI, waist, abdominal, hip circumferences) and lower waist/hip ratio (p<0.05) compared to the CTRL group. The association between the polymorphism alleles related to the rs1801133 MTHFR gene and the body composition values LIPPY carriers (+) showed an increase in fat tissue of legs and fat region of legs percentage, arm's fat mass (g), leg's fat mass (g), and leg's lean mass (g) (p<0.05) compared to CTRL (+). Lean/fat arms and lean/fat legs were lower (p<0.05) in LIPPY (+) than in CTRL (+). In the LIPPY (+), the risk of developing the lipedema disease was 2.85 times higher (OR=2.85; p<0.05; 95% confidence interval = 0.842-8.625) with respect to LIPPY (-) and CTRL. Conclusions: The presence or absence of MTHFR polymorphism offers predictive parameters that could better characterize women with lipedema based on the association between body composition and MTHFR presence

Drying of a Microdroplet of Water Suspension of Nanoparticles: from Surface Aggregates to Microcrystal

The method of formation of nanoparticle aggregates such as high-coverage spherical shells of microspheres or 3-D micro crystals grown in the geometry unaffected by a substrate is described. In the reported experiment, the evaporation of single levitated water droplet containing 200 nm diameter polystyrene spheres was studied. Successive stages of the drying process were discussed by analyzing the intensity of light elastically scattered by the evaporating droplet. The numerically simulated self-assembly coincides nicely with the observed morphologies resulting from transformation of a droplet of suspension into a solid microcrystal via kinetically driven self-assembly of nanostructures.Comment: 5 pages, 6 figure

Topoisomerase II-Mediated DNA Damage Is Differently Repaired during the Cell Cycle by Non-Homologous End Joining and Homologous Recombination

Topoisomerase II (Top2) is a nuclear enzyme involved in several metabolic processes of DNA. Chemotherapy agents that poison Top2 are known to induce persistent protein-mediated DNA double strand breaks (DSB). In this report, by using knock down experiments, we demonstrated that Top2α was largely responsible for the induction of γH2AX and cytotoxicity by the Top2 poisons idarubicin and etoposide in normal human cells. As DSB resulting from Top2 poisons-mediated damage may be repaired by non-homologous end joining (NHEJ) or homologous recombination (HR), we aimed to analyze both DNA repair pathways. We found that DNA-PKcs was rapidly activated in human cells, as evidenced by autophosphorylation at serine 2056, following Top2-mediated DNA damage. The chemical inhibition of DNA-PKcs by wortmannin and vanillin resulted in an increased accumulation of DNA DSB, as evaluated by the comet assay. This was supported by a hypersensitive phenotype to Top2 poisons of Ku80- and DNA-PKcs- defective Chinese hamster cell lines. We also showed that Rad51 protein levels, Rad51 foci formation and sister chromatid exchanges were increased in human cells following Top2-mediated DNA damage. In support, BRCA2- and Rad51C- defective Chinese hamster cells displayed hypersensitivity to Top2 poisons. The analysis by immunofluorescence of the DNA DSB repair response in synchronized human cell cultures revealed activation of DNA-PKcs throughout the cell cycle and Rad51 foci formation in S and late S/G2 cells. Additionally, we found an increase of DNA-PKcs-mediated residual repair events, but not Rad51 residual foci, into micronucleated and apoptotic cells. Therefore, we conclude that in human cells both NHEJ and HR are required, with cell cycle stage specificity, for the repair of Top2-mediated reversible DNA damage. Moreover, NHEJ-mediated residual repair events are more frequently associated to irreversibly damaged cells

Is a phenylalanine-glucosamine derivative able to affect the main responsible for IκB protein phosphorylation?

Nuclear factor κB (NFkB) is an ubiquitous transcription factor well known for its role in the innate immune response. In fact, it is involved as activator of inflammatory mediators such as cytokines. It consists of subunit dimers including p65, RelB, c-Rel, p50 and p52. Under normal conditions, they are bound in the cytosol by an inhibitory protein known as inhibitor of NFkB (IkB). The responsible for IkB phosphorylation is IkB kinase (IKK) complex, consisting of two catalytic subunits (IKKα and IKKβ) and a regulatory one. When activated, IKK phosphorylates IkB, thus tagging it for proteasomal degradation and freeing the NFkB subunit dimers which translocate to the nucleus and bind to specific DNA sequences within the promoter region of vast array of genes. Previous in vivo and in vitro studies in our laboratory demonstrate that Glucosamine (GlcN) and its N-acetyl phenylalanine derivative (NAPA) are able to counteract effects induced by inflammatory cytokines, particularly modulating some genes, under the control of NFkB, upregulated by TNF-α. So, the aim of this study is to better understand whether these two molecules may affect the activity of IKKα and IKKβ through some specific interactions. HTB-94, treated respectively with TNF-α and single molecules, are grown, lysated, incubated with anti-IKKα antibody and eventually treated with magnetic beads. This assay is performed to immunoprecipitate the activated IKK complex. Subsequently, an in vitro kinase assay is performed using a recombinant protein as substrate while in presence and absence of both molecules, to analyze the immunoprecipitated complex (IP-IKK). An immunocytochemistry is performed to visualize if IKKα re-localization is affected by GlcN and NAPA. Owing to immunoprecipitated complex formation, molecules can directly interact with kinases because they don’t need to cross cell membrane. In presence of GlcN, IP-IKK can phosphorylate the recombinant substrate, whileas in presence of NAPA 0.5mM the phosphorylation is inhibited. Further studies are performed evaluating IKK inhibition activity by GlcN and NAPA on recombinant protein using recombinant IKKα and IKKβ molecules. As previously observed, NAPA strongly inhibits IKKα activity on itself and on the recombinant substrate, but no effect is observed on IKKβ. On the contrary, GlcN cannot inhibit either IKKα or IKKβ at any concentrations used. In immunocytochemistry IKKα is mainly cytoplasmic in untreated cells, but it accumulates in nucleus under TNF-α stimulus. Pre-treatment with both molecules shows a mainly cytoplasmic IKKα localization. In conclusion, it is observed that both molecules affect IKKα localization, but only NAPA is an effective IkB phosphorylation inhibitor explaining how both molecules modulate expression level gene under NFkB control. Scotto d'Abusco A; Politi A; Giordano C; Scandurra R¸ Arthritis Research & Therapy 2010; doi: 10.1186/ar2920

PLA and PBAT-Based Electrospun Fibers Functionalized with Antibacterial Bio-Based Polymers

Antimicrobial fibers based on biodegradable polymers, poly(lactic acid) (PLA),and poly(butylene adipate-co-terephthalate) (PBAT) are prepared byelectrospinning. For this purpose, a biodegradable/bio-based polyitaconatecontaining azoles groups (PTTI) is incorporated at 10 wt.% into theelectrospinning formulations. The resulting fibers functionalized with azolemoieties are uniform and free of beads. Then, the accessible azole groups aresubjected toN-alkylation, treatment that provides cationic azolium groupswith antibacterial activity at the surface of fibers. The positive charge density,roughness, and wettability of the cationic fibers are evaluated and comparedwith flat films. It is confirmed that these parameters exert an important effecton the antimicrobial properties, as well as the length of the alkylating agentand the hydrophobicity of the matrix. The quaternized PLA/PTTI fibers exhibitthe highest efficiency against the tested bacteria, yielding a 4-Log reductionagainstS. aureusand 1.7-Log against MRSA. Then, biocompatibility andbioactivity of the fibers are evaluated in terms of adhesion, morphology andviability of fibroblasts. The results show no cytotoxic effect of the samples,however, a cytostatic effect is appreciated, which is ascribed to the strongelectrostatic interactions between the positive charge at the fiber surface andthe negative charge of the cell membranesThis work was funded by the MICINN (PID2019-104600RB-I00), the Agen-cia Estatal de Investigación (AEI, Spain) and Fondo Europeo de DesarrolloRegional (FEDER, EU) and by CSIC (LINKA20364). A.C. acknowledges MI-CIU for his FPU fellowship FPU18/01776. The negativ exponents were cor-rected on January 16, 202