Browsing by Author "Espinoza, Javier"

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    Effect of lithium on the properties of a liquid crystal formed by sodium dodecylsulphate and decanol in aqueous solution
    (AMER INST PHYSICS, 2013) Bahamonde Padilla, V. E.; Espinoza, Javier; Weiss Lopez, B. E.; Lopez Cascales, J. J.; Montecinos, R.; Araya Maturana, R.
    Understanding the molecular interactions that rule the physicochemical properties of molecular assemblies is of particular interest when trying to explain the behavior of much more complicated systems, such as the cell membranes. This work was devoted to study a discotic nematic lyotropic liquid crystal, formed by sodium dodecylsulphate (3% SDS-d(25)) and decanol (20% DeOH-alpha-d(2)), dissolved in aqueous solutions (0.1% D2O) of Na2SO4 or Li2SO4. The average size of the aggregates was estimated using fluorescence quenching experiments, and their dynamics were studied by measuring the H-2-NMR quadrupole splitting (Delta nu(Q)) and the longitudinal relaxation times (T-1) of the deuterated species. To provide an atomic insight into these assemblies, molecular dynamics simulations of the systems were carried out with atomic detail. As a previous step in this study, a reparameterization of the standard GROMOS 87 force field was required to perform the equilibrated simulations and to prevent instabilities emerging during the simulations. Finally, an excellent agreement between simulation and experimental data was obtained. In addition, variations in the long range electrostatic interactions at the aggregate/solution interface, the orientation and the re-orientational relaxation time of the water dipole, the translational diffusion coefficient of sodium ions, and the amphiphile-counterion coordination associated with the presence of Li+ in the solution were other key aspects investigated to explain the variation in the quadrupole splittings (Delta nu(Q)) in the presence of lithium in solution. (C) 2013 AIP Publishing LLC.
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    FOXO1 regulates wound-healing responses in human gingival fibroblasts
    (2024) Rojas, Leticia; Tobar, Nicolas; Espinoza, Javier; Rios, Susana; Martinez, Constanza; Martinez, Jorge; Graves, Dana T.; Smith, Patricio C.
    Background and objective: Forkhead box-O 1 (FOXO1) is a transcription factor actively involved in oral wound healing at the epithelial barrier. However, less is known regarding the role of FOXO1 during the tissue repair response in the connective tissue compartment. This study explored the involvement of FOXO1 in the modulation of fibroblast activity related to wound healing. Methods: Primary cultures of human gingival fibroblasts were obtained from four healthy young donors. Myofibroblastic differentiation, collagen gel contraction, cell migration, cell spreading, and integrin activation were evaluated in the presence or absence of a FOXO1 inhibitor (AS1842856). Variations in mRNA and proteins of interest were evaluated through qRT-PCR and western blot, respectively. Distribution of actin, alpha-smooth muscle actin, and beta 1 integrin was evaluated using immunofluorescence. FOXO1 and TGF-beta 1 expression in gingival wound healing was assessed by immunohistochemistry in gingival wounds performed in C57BL/6 mice. Images were analyzed using ImageJ/Fiji. ANOVA or Kruskal-Wallis test followed by Tukey's or Dunn's post-hoc test was performed. All data are expressed as mean +/- SD. p < .05 was considered statistically significant. Results: FOXO1 inhibition caused a decrease in the expression of the myofibroblastic marker alpha-SMA along with a reduction in fibronectin, type I collagen, TGF-beta 1, and beta 1 integrin mRNA level. The FOXO1 inhibitor also caused decreases in cell migration, cell spreading, collagen gel contraction, and beta 1 integrin activation. FOXO1 and TGF-beta 1 were prominently expressed in gingival wounds in fibroblastic cells located at the wound bed. Conclusion: The present study indicates that FOXO1 plays an important role in the modulation of several wound-healing functions in gingival fibroblast. Moreover, our findings reveal an important regulatory role for FOXO1 on the differentiation of gingival myofibroblasts, the regulation of cell migration, and collagen contraction, all these functions being critical during tissue repair and fibrosis.
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    KDEL receptor regulates secretion by lysosome relocation- and autophagy-dependent modulation of lipid-droplet turnover
    (2019) Tapia, Diego; Zamora, Constanza; Espinoza, Javier; Rizzo, Riccardo; González Cárdenas, Alexis; Fuentes Peña, Danitza Natalia; Hernández, Sergio; Cavieres, Viviana A.; Guzmán, Fanny; Arriagada, Gloria; Yuseff Sepúlveda, María Isabel; Mardones, Gonzalo A.; Burgos , Patricia V.; Luini, Alberto; González, Alfonso; Cancino, Jorge; Jiménez, Tomás; Soza Gajardo, Andrea