0000000000056461
AUTHOR
Pilar Sepúlveda
showing 22 related works from this author
Diagnosis of systemic candidiasis by enzyme immunoassay detection of specific antibodies to mycelial phase cell wall and cytoplasmic candidal antigens
1993
Diagnosis of systemic Candida infections was attempted by the use of an enzyme-linked immunosorbent assay (EIA) to detect IgG antibodies towards cell wall-bound and cytoplasmic candidal antigens. Cell wall antigens were sequentially solubilized by treatment of germinated blastoconidia of Candida albicans (ATCC 26555 strain) with beta-mercaptoethanol (beta ME extract) and digestion with Zymolyase 20T, a beta-glucanase preparation (Zymolyase extract). Protoplasts obtained after treatment with Zymolyase were osmotically lysed (cytoplasmic antigens). Sera were obtained from patients with systemic (n = 28) and superficial (n = 46) candidiasis. Control sera were obtained from normal healthy indiv…
Cloning and characterization of a cDNA coding forCandida albicanspolyubiquitin
1996
Immunoscreening of a Candida albicans cDNA library in the expression vector lambda gt11 with rabbit polyclonal antibodies against the 37 kDa cell surface laminin receptor of C albicans resulted in the isolation of a cDNA clone of 0.9 kb. Sequencing of this clone demonstrated a full length open reading frame encoding the polyubiquitin, which contains three tandem copies, head-to-tail spacerless repeats, of the 228 nucleotides coding for the 76 amino acids of the ubiquitin protein, which is identical to that of Saccharomyces cerevisiae. The third copy possesses an extra C-terminal amino acid which is distinct to that found in S. cerevisiae. Northern blot analysis revealed a single mRNA popula…
HIF-Overexpression and Pro-Inflammatory Priming in Human Mesenchymal Stromal Cells Improves the Healing Properties of Extracellular Vesicles in Exper…
2021
Extracellular vesicles (EVs) derived from mesenchymal stromal cells (MSCs) have therapeutic potential in the treatment of several immune disorders, including ulcerative colitis, owing to their regenerative and immunosuppressive properties. We recently showed that MSCs engineered to overexpress hypoxia-inducible factor 1-alpha and telomerase (MSC-T-HIF) and conditioned with pro-inflammatory stimuli release EVs (EVMSC-T-HIFC) with potent immunomodulatory activity. We tested the efficacy of EVMSC-T-HIFC to repolarize M1 macrophages (Mφ1) to M2-like macrophages (Mφ2-like) by analyzing surface markers and cytokines and performing functional assays in co-culture, including efferocytosis and T-cel…
Polycaprolactone/gelatin-based scaffolds with tailored performance: in vitro and in vivo validation
2019
Abstract Nanofibrous scaffolds composed of polycaprolactone (PCL) and gelatin (Ge) were obtained through a hydrolytic assisted electrospinning process. The PCL-to-Ge proportion (100/0 to 20/80), as well as the dissolution time (24, 48, 72, 96, 120 h) into a 1:1 formic/acetic acid solvent before electrospinning were modified to obtain the different samples. A strong influence of these factors on the physicochemical properties of the scaffolds was observed. Higher Ge percentage reduced crystallinity, allowed a uniform morphology and increased water contact angle. The increase in the dissolution time considerably reduced the molar mass and, subsequently, fibre diameter and crystallinity were a…
Conductive polycaprolactone/gelatin/polyaniline nanofibres as functional scaffolds for cardiac tissue regeneration
2022
Abstract The endorsement of functional features such as biocompatibility, mechanical integrity, or electrical conductivity to tissue engineering (TE) scaffolds is essential to stimulate cell adhesion and proliferation. In this study, electrospun nanofibers based on polycaprolactone (PCL) and gelatin (Ge) (ratios 60/40, 50/50, and 40/60), and polyaniline (PAni) particles (0.25, 0.50, and 1.00%wt) were prepared. The time of dissolution in an acid solvent mixture before electrospinning allowed for obtaining nanofibers with controlled features. Changes in the molar mass (Mn from 90·103 to 15·103 g·mol−1), in the crystalline microstructure (Xc from 60 to 25%) and the surface morphology (diameter…
miR-133a Enhances the Protective Capacity of Cardiac Progenitors Cells after Myocardial Infarction
2014
Summary miR-133a and miR-1 are known as muscle-specific microRNAs that are involved in cardiac development and pathophysiology. We have shown that both miR-1 and miR-133a are early and progressively upregulated during in vitro cardiac differentiation of adult cardiac progenitor cells (CPCs), but only miR-133a expression was enhanced under in vitro oxidative stress. miR-1 was demonstrated to favor differentiation of CPCs, whereas miR-133a overexpression protected CPCs against cell death, targeting, among others, the proapoptotic genes Bim and Bmf. miR-133a-CPCs clearly improved cardiac function in a rat myocardial infarction model by reducing fibrosis and hypertrophy and increasing vasculari…
Mesenchymal Stem Cells Provide Better Results Than Hematopoietic Precursors for the Treatment of Myocardial Infarction
2010
Objectives The purpose of this study was to compare the ability of human CD34(+) hematopoietic stem cells and bone marrow mesenchymal stem cells (MSC) to treat myocardial infarction (MI) in a model of permanent left descendent coronary artery (LDA) ligation in nude rats. Background Transplantation of human CD34(+) cells and MSC has been proved to be effective in treating MI, but no comparative studies have been performed to elucidate which treatment prevents left ventricular (LV) remodelling more efficiently. Methods Human bone marrow MSC or freshly isolated CD34(+) cells from umbilical cord blood were injected intramyocardially in infarcted nude rats. Cardiac function was analyzed by echoc…
HIF-1α and Pro-Inflammatory Signaling Improves the Immunomodulatory Activity of MSC-Derived Extracellular Vesicles
2021
Despite the strong evidence for the immunomodulatory activity of mesenchymal stromal cells (MSCs), clinical trials have so far failed to clearly show benefit, likely reflecting methodological shortcomings and lack of standardization. MSC-mediated tissue repair is commonly believed to occur in a paracrine manner, and it has been stated that extracellular vesicles (EVs) secreted by MSCs (EVMSC) are able to recapitulate the immunosuppressive properties of parental cells. As a next step, clinical trials to corroborate preclinical studies should be performed. However, effective dose in large mammals, including humans, is quite high and EVs industrial production is hindered by the proliferative s…
Electrospun poly(hydroxybutyrate) scaffolds promote engraftment of human skin equivalents via macrophage M2 polarization and angiogenesis.
2018
Human dermo-epidermal skin equivalents (DE) comprising in vitro expanded autologous keratinocytes and fibroblasts are a good option for massive burn treatment. However, the lengthy expansion time required to obtain sufficient surface to cover an extensive burn together with the challenging surgical procedure limits their clinical use. The integration of DE and biodegradable scaffolds has been proposed in an effort to enhance their mechanical properties. Here, it is shown that poly(hydroxybutyrate) electrospun scaffolds (PHB) present good biocompatibility both in vitro and in vivo and are superior to poly-epsilon-caprolactone electrospun scaffolds as a substrate for skin reconstruction. Impl…
A comparative study on cell wall antigens and cell surface hydrophobicity in clinical isolates ofCandida albicans
1994
Characterization of common cell surface-bound antigens in Candida albicans strains, particularly those expressed in the walls of mycelial cells might be useful in the diagnosis of systemic candidiasis. Hence, antigenic similarities among wall proteins and mannoproteins from C. albicans clinical serotype A and B isolates, were studied using polyclonal (mPAbs) and monoclonal (MAb 4C12) antibodies raised against wall antigens from the mycelial form of a common C. albicans serotype A laboratory strain (ATCC 26555). Zymolyase digestion of walls isolated from cells of the different strains studied grown at 37 degrees C (germination conditions), released, in all cases, numerous protein and mannopr…
In vitro validation of biomedical polyester-based scaffolds: Poly(lactide-co-glycolide) as model-case
2018
[EN] Monitoring and understanding the in vitro behaviour of polyester based scaffolds both comprising the study of the hydrolytic degradation and the cell seeding viability is essential to ensure the desired functionality, according to a given biomedical purpose. As a model case to compare the performance of techniques to monitor the in vitro behaviour, poly(lactide-co-glycolide) (PLGA) scaffolds were chosen. The in vitro hydrolytic degradation of PLGA scaffolds was carried out in water and phosphate buffered saline (PBS). The evolution of the mass loss, the molar mass, the thermal properties and the surface morphology were monitored. The hydrolytic degradation media was correspondingly eva…
Co-administration of human MSC overexpressing HIF-1α increases human CD34+ cell engraftment in vivo
2021
Abstract Background Poor graft function or graft failure after allogeneic stem cell transplantation is an unmet medical need, in which mesenchymal stromal cells (MSC) constitute an attractive potential therapeutic approach. Hypoxia-inducible factor-1α (HIF-1α) overexpression in MSC (HIF-MSC) potentiates the angiogenic and immunomodulatory properties of these cells, so we hypothesized that co-transplantation of MSC-HIF with CD34+ human cord blood cells would also enhance hematopoietic stem cell engraftment and function both in vitro and in vivo. Methods Human MSC were obtained from dental pulp. Lentiviral overexpression of HIF-1α was performed transducing cells with pWPI-green fluorescent pr…
Cloning of a cDNA fragment encoding part of the protein moiety of the 58-kDa fibrinogen-binding mannoprotein of Candida albicans
2006
Immunoscreening of a Candida albicans expression library with antibodies against the 58 kDa fibrinogen-binding mannoprotein (mp58) of the fungus resulted in the isolation of clones encoding the protein moiety of this molecule. Sequence of the 0.9 kb cDNA of one of the clones selected for further analysis, revealed an open reading frame coding for 292 amino acids, which displays sequence similarity to proteins belonging to a family of immunodominant antigens of Aspergillus spp. The gene corresponding to this cDNA was named FBP1 (fibrinogen-binding protein). These results represent the first report on the identification of C. albicans genes encoding surface receptors for host proteins.
Evidence for the presence of collagenous domains in Candida albicans cell surface proteins
1995
Rabbit polyclonal antibodies (PAbs) directed towards the amino-terminal cysteine-rich 7S domain (PAb anti-7S), the major internal collagenous domain (PAb anti-type IV), and the C-terminal noncollagenous region (PAb anti-NC1) of the type IV collagen molecule were probed by indirect immunofluorescence against Candida albicans blastoconidia and germinated blastoconidia. Most nongerminating cells and mother blastoconidia from which germ tubes originated showed strong fluorescence when PAb anti-7S was used, whereas with PAb anti-type IV, fluorescence was found almost exclusively on the surface of filamentous forms. A patched fluorescent pattern rather than a homogenous confluent fluorescence was…
IL1β Induces Mesenchymal Stem Cells Migration and Leucocyte Chemotaxis Through NF-κB
2012
Mesenchymal stem cells are often transplanted into inflammatory environments where they are able to survive and modulate host immune responses through a poorly understood mechanism. In this paper we analyzed the responses of MSC to IL-1β: a representative inflammatory mediator. Microarray analysis of MSC treated with IL-1β revealed that this cytokine activateds a set of genes related to biological processes such as cell survival, cell migration, cell adhesion, chemokine production, induction of angiogenesis and modulation of the immune response. Further more detailed analysis by real-time PCR and functional assays revealed that IL-1β mainly increaseds the production of chemokines such as CC…
Trends of maxillofacial trauma: An update from the prospective register of a multicenter study in emergency services of Chile
2019
Background Determine the behavior of the maxillofacial trauma of adults treated in 3 tertiary care centers in the central zone of Chile. Material and Methods Descriptive, cross-sectional, multicenter study, based on the prospective records of maxillofacial trauma cases attended between May 2016 and April 2017 by dental and maxillofacial clinical teams of Adult Emergency Units of hospitals Dr. Sótero del Río (metropolitan region), Carlos Van Buren and Dr. Gustavo Fricke (region V). Age, sex, date of occurrence, type of trauma according to ICD-10, etiology, legal medical prognosis and associated injuries were recorded, stratifying by sex and age. Chi square and unpaired Wilcoxon tests were us…
Circulating exosomes deliver free fatty acids from the bloodstream to cardiac cells: Possible role of CD36
2019
Regulation of circulating free fatty acid (FFA) levels and delivery is crucial to maintain tissue homeostasis. Exosomes are nanomembranous vesicles that are released from diverse cell types and mediate intercellular communication by delivering bioactive molecules. Here, we sought to investigate the uptake of FFAs by circulating exosomes, the delivery of FFA-loaded exosomes to cardiac cells and the possible role of the FFA transporter CD36 in these processes. Circulating exosomes were purified from the serum of healthy donors after an overnight fast (F) or 20 minutes after a high caloric breakfast (postprandial, PP). Western blotting, Immunogold Electron Microscopy and FACS analysis of circu…
Ubiquitin-like epitopes associated with Candida albicans cell surface receptors
1996
We have recently reported the cloning of a Candida albicans polyubiquitin gene and the presence of ubiquitin in the cell wall of this fungus. The polyubiquitin cDNA clone was isolated because of its reactivity with antibodies generated against the candidal 37-kDa laminin-binding protein. In the present study, we have further investigated the relationship between ubiquitin and cell wall components displaying receptor-like activities, including the 37-kDa laminin receptor, the 58-kDa fibrinogen-binding mannoprotein, and the candidal C3d receptor. Two-dimensional electrophoretic analysis and immunoblot experiments with antibodies against ubiquitin and the individually purified receptor-like mo…
Human Dental Pulp Stem Cells Improve Left Ventricular Function, Induce Angiogenesis, and Reduce Infarct Size in Rats with Acute Myocardial Infarction
2008
Abstract Human dental pulp contains precursor cells termed dental pulp stem cells (DPSC) that show self-renewal and multilineage differentiation and also secrete multiple proangiogenic and antiapoptotic factors. To examine whether these cells could have therapeutic potential in the repair of myocardial infarction (MI), DPSC were infected with a retrovirus encoding the green fluorescent protein (GFP) and expanded ex vivo. Seven days after induction of myocardial infarction by coronary artery ligation, 1.5 × 106 GFP-DPSC were injected intramyocardially in nude rats. At 4 weeks, cell-treated animals showed an improvement in cardiac function, observed by percentage changes in anterior wall thic…
Preliminary characterization of the material released to the culture medium by Candida albicans yeast and mycelial cells.
1995
Culture filtrate concentrates were obtained from Candida albicans yeast and mycelial cells grown in the presence of 14C-protein hydrolysate for radioactive labeling of cellular polypeptides. Both growth forms released to the medium minor but significant amounts of proteinaceous materials. The analysis of culture filtrate concentrates by means of SDS-polyacrylamide gel electrophoresis and fluorography revealed a similar and complex electrophoretic pattern, though some qualitative and quantitative differences between samples obtained from yeast and mycelial cells were observed. Materials released, mostly composed of mannoproteins as shown by their affinity towards concanavalin A, presented (i…
ATR-FTIR spectroscopy for the routine quality control of exosome isolations
2021
Abstract Exosomes are nanosized vesicles containing specific cargos of DNA, RNA, proteins, metabolites, and intracellular and membrane lipids. Exosome isolation needs to be optimized carefully depending on the type of biofluid and tissue and the retrieved exosomes need to be characterized. The main objective of this study was to determine the feasibility of a multimodal analysis of Attenuated Total Reflectance – Fourier Transform Infrared (ATR-FTIR) spectroscopy and UPLC–QqTOF-MSMS for the development of a routine quality control tool of isolated exosomes and the rapid characterization of their lipid profiles and total protein content. Using human milk as model example, exosomes were isolat…
Expression of the fibrinogen binding mannoprotein and the laminin receptor of Candida albicans in vitro and in infected tissues.
1996
We have previously reported a 37 kDa laminin-binding protein (p37) and a 58 kDa fibrinogen-binding mannoprotein (mp58) on the surface of Candida albicans. A few yeast cells expressed both functional receptors at the surface while germ tubes expressed a functional mp58 fibrinogen but not a functional p37 laminin receptor. These receptors were heterogeneously dispersed at the surface as shown by binding of rabbit antiserum to mp58 (PAb anti-mp58) and antiserum to the human high affinity laminin receptor. In this report we have used a dual fluorescence technique to determine if the two receptors colocalize, perhaps as part of a receptor complex. Fibrinogen was used as a probe for mp58 and poly…