Publications by authors named "Ana Lucia Fuentes"

7 Publications

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Increased peripheral blood neutrophil activation phenotypes and NETosis in critically ill COVID-19 patients: a case series and review of the literature.

Clin Infect Dis 2021 May 14. Epub 2021 May 14.

Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, University of California San Diego (UCSD), La Jolla, CA 92093, USA.

Background: Increased inflammation has been well defined in COVID-19, while definitive pathways driving severe forms of this disease remain uncertain. Neutrophils are known to contribute to immunopathology in infections, inflammatory diseases and acute respiratory distress syndrome (ARDS), a primary cause of morbidity and mortality in COVID-19. Changes in neutrophil function in COVID-19 may give insight into disease pathogenesis and identify therapeutic targets.

Methods: Blood was obtained serially from critically ill COVID-19 patients for eleven days. Neutrophil extracellular trap formation (NETosis), oxidative burst, phagocytosis and cytokine levels were assessed. Lung tissue was obtained immediately post-mortem for immunostaining. Pubmed searches for neutrophils, lung and COVID-19 yielded ten peer-reviewed research articles in English.

Results: Elevations in neutrophil-associated cytokines IL-8 and IL-6, and general inflammatory cytokines IP-10, GM-CSF, IL-1b, IL-10 and TNF, were identified both at first measurement and across hospitalization (p<0.0001). COVID neutrophils had exaggerated oxidative burst (p<0.0001), NETosis (p<0.0001) and phagocytosis (p<0.0001) relative to controls. Increased NETosis correlated with leukocytosis and neutrophilia, and neutrophils and NETs were identified within airways and alveoli in lung parenchyma of 40% of SARS-CoV-2 infected lungs available for examination (2 out of 5). While elevations in IL-8 and ANC correlated with disease severity, plasma IL-8 levels alone correlated with death.

Conclusions: Literature to date demonstrates compelling evidence of increased neutrophils in the circulation and lungs of COVID-19 patients. importantly, neutrophil quantity and activation correlates with severity of disease. Similarly, our data shows that circulating neutrophils in COVID-19 exhibit an activated phenotype with enhanced NETosis and oxidative burst.
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http://dx.doi.org/10.1093/cid/ciab437DOI Listing
May 2021

Transforming Growth Factor-β1 Decreases β-Agonist-induced Relaxation in Human Airway Smooth Muscle.

Am J Respir Cell Mol Biol 2019 08;61(2):209-218

1Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania.

Helper T effector cytokines implicated in asthma modulate the contractility of human airway smooth muscle (HASM) cells. We have reported recently that a profibrotic cytokine, transforming growth factor (TGF)-β1, induces HASM cell shortening and airway hyperresponsiveness. Here, we assessed whether TGF-β1 affects the ability of HASM cells to relax in response to β-agonists, a mainstay treatment for airway hyperresponsiveness in asthma. Overnight TGF-β1 treatment significantly impaired isoproterenol (ISO)-induced relaxation of carbachol-stimulated, isolated HASM cells. This single-cell mechanical hyporesponsiveness to ISO was corroborated by sustained increases in myosin light chain phosphorylation. In TGF-β1-treated HASM cells, ISO evoked markedly lower levels of intracellular cAMP. These attenuated cAMP levels were, in turn, restored with pharmacological and siRNA inhibition of phosphodiesterase 4 and Smad3, respectively. Most strikingly, TGF-β1 selectively induced phosphodiesterase 4D gene expression in HASM cells in a Smad2/3-dependent manner. Together, these data suggest that TGF-β1 decreases HASM cell β-agonist relaxation responses by modulating intracellular cAMP levels via a Smad2/3-dependent mechanism. Our findings further define the mechanisms underlying β-agonist hyporesponsiveness in asthma, and suggest TGF-β1 as a potential therapeutic target to decrease asthma exacerbations in severe and treatment-resistant asthma.
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http://dx.doi.org/10.1165/rcmb.2018-0301OCDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6670035PMC
August 2019

Nutritional status at diagnosis of cancer in children and adolescents in Guatemala and its relationship to socioeconomic disadvantage: A retrospective cohort study.

Pediatr Blood Cancer 2019 06 7;66(6):e27647. Epub 2019 Feb 7.

Departments of Pediatrics, Pathology and Medicine, McMaster University, Hamilton, Ontario, Canada.

Background: At least 80% of children with cancer live in low- and middle-income countries where the prevalence of malnutrition and socioeconomic disadvantage is high. We examined the relationship between nutritional status (NS), assessed by arm anthropometry, and socioeconomic status (SES) in children diagnosed with cancer at Unidad Nacional de Oncologia Pediatrica (UNOP) in Guatemala over a three-year period.

Method: Patients aged 0 to 18 years of age diagnosed between January 2015 and December 2017 were included. NS was evaluated by mid-upper arm circumference, triceps skin fold thickness, and serum albumin level, and subjects were classified as adequately nourished, moderately depleted, and severely depleted nutritionally. SES was measured by a 15-item instrument developed at UNOP.

Results: Of 1365 patients diagnosed in the study period, 1060 (78%) fulfilled the eligibility criteria. Only 6% of patients were classified as medium to high, the remainder as medium-low to extremely low SES. Almost 47% were severely depleted at diagnosis, 19% moderately depleted, and 34% adequately nourished. SES was shown to be a determinant of NS; with progressively lower SES, the probability of a decline in NS increased by a factor of 1.04 points (P < 0.0001). Leukemia and lymphoma were also important predictors of nutritional depletion with odds ratios of 6.08 (95% CI, 1.74-28.28; P = 0.008) for leukemias and 4.83 (95% CI, 1.33-23.03; P = 0.03) for lymphomas.

Conclusion: Both low SES and a diagnosis of leukemia or lymphoma are strong predictors of poor NS at diagnosis in children with cancer in Guatemala.
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http://dx.doi.org/10.1002/pbc.27647DOI Listing
June 2019

Effects of Toll-like receptor ligands on RAW 264.7 macrophage morphology and zymosan phagocytosis.

Tissue Cell 2016 Aug 22;48(4):389-96. Epub 2016 Apr 22.

Department of Molecular Biology and Biochemistry, Simon Fraser University, 8888 University Drive, Burnaby, B.C. V5A 1S6 Canada.

In this study we compared the effects of the Toll-like receptor (TLR) ligands lipopolysaccharide (LPS), flagellin, the synthetic bacterial triacylated lipopeptide Pam3-Cys-Ser-Lys4 (Pam3CSK4), Polyinosinic:polycytidylic acid (Poly I:C), and macrophage-activating lipopeptide (MALP-2), which are TLR4, TLR5, TLR1/2, TLR3, and TLR2/6 agonists, respectively, on cell morphology and phagocytosis of zymosan particles, derived from Saccharomyces cerevisiae, and rich in fungal PAMPs including beta-glucan, mannose, and chitin. LPS, Pam3CSK4, and MALP-2 induced an activated macrophage phenotype and enhanced zymosan phagocytosis. In contrast, flagellin and Poly I:C, respectively, had little effect on cell morphology and phagocytosis. We examined the role of scavenger receptor A (SR-A) on zymosan phagocytosis. Cells cultured in medium alone expressed SR-A, and LPS induced further expression of the receptor. We also observed inhibitory effects of scavenger receptor antagonists fucoidan, dextran sulphate, and Polyinosinic (Poly I), respectively, on zymosan phagocytosis of cells in medium alone and those pre-treated with LPS. We conclude that exposure to specific TLR ligands impacts both cellular morphology and phagocytic capacity, and that scavenger receptors contribute to zymosan ingestion as well as LPS-induced augmentation of phagocytosis.
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http://dx.doi.org/10.1016/j.tice.2016.04.002DOI Listing
August 2016

Identification of Plant Extracts that Inhibit the Formation of Diabetes-Linked IAPP Amyloid.

J Herb Med 2016 Mar;6(1):37-41

Department of Chemistry and Biochemistry, Loyola Marymount University, 1 LMU Drive, Los Angeles, CA 90045.

The extracts of 27 vegetables, spices and herbs were screened for their functional ability to inhibit the aggregation of islet amyloid polypeptide (IAPP, amylin) into toxic amyloid aggregates. The aggregation of IAPP has been directly linked to the death of pancreatic β-islet cells in type 2 diabetes. Inhibiting the aggregation of IAPP is believed to have the potential to slow, if not prevent entirely, the progression of this disease. As vegetables, spices and herbs are known to possess many different positive health effects, the extracts of 27 plants (abundant within the United States and spanning several plant families) were screened for their ability to inhibit the formation of toxic IAPP aggregates. Their anti-amyloid activities were assessed through (1) thioflavin T binding assays, (2) visualization of amyloid fibers using atomic force microscopy and (3) cell rescue studies. From this research, mint, peppermint, red bell pepper and thyme emerged as possessing the greatest anti-amyloid activity.
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http://dx.doi.org/10.1016/j.hermed.2015.11.001DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4815265PMC
March 2016

Lipopolysaccharide-mediated enhancement of zymosan phagocytosis by RAW 264.7 macrophages is independent of opsonins, laminarin, mannan, and complement receptor 3.

J Surg Res 2014 Jun 17;189(2):304-12. Epub 2014 Mar 17.

Biology Department, Faculty of Science and Technology, New Westminster British Columbia, Canada. Electronic address:

Background: Fungal and bacterial coinfections are common in surgical settings; however, little is known about the effects of polymicrobial interactions on the cellular mechanisms involved in innate immune recognition and phagocytosis.

Materials And Methods: Zymosan particles, cell wall derivatives of the yeast Saccharomyces cerevisiae, are used to model fungal interactions with host immune cells since they display carbohydrates, including beta-glucan, that are characteristic of fungal pathogens. Using in vitro cell culture, RAW 264.7 macrophages were challenged with zymosan, and phagocytosis determined via light microscopy. The effects of different concentrations of lipopolysaccharide (LPS) on zymosan phagocytosis were assessed. In addition, the transfer of supernatant from LPS-treated cells to naïve cells, the effects of soluble carbohydrates laminarin, mannan, or galactomannan, and the impact of complement receptor 3 (CR3) inhibition on phagocytosis were also determined.

Results: LPS enhanced phagocytosis of zymosan in a dose-dependent manner. Transfer of supernatants from LPS-primed cells to naïve cells had no effect on phagocytosis. Laminarin inhibited zymosan phagocytosis in naïve cells but not in LPS-primed cells. Neither mannan, galactomannan, nor CR3 inhibition had a significant effect on ingestion of unopsonized zymosan in naïve or LPS-treated cells.

Conclusions: Zymosan recognition by naïve cells is inhibited by laminarin, but not mannan, galactomannan, or CR3 inhibition. LPS enhancement of phagocytosis is laminarin insensitive and not mediated by supernatant factors or zymosan engagement by the mannose or CR3 receptors. Our data suggest alternative mechanisms of zymosan recognition in the presence and absence of LPS.
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http://dx.doi.org/10.1016/j.jss.2014.03.024DOI Listing
June 2014

Laminarin, a soluble beta-glucan, inhibits macrophage phagocytosis of zymosan but has no effect on lipopolysaccharide mediated augmentation of phagocytosis.

Int Immunopharmacol 2011 Nov 19;11(11):1939-45. Epub 2011 Aug 19.

Biology Department, Douglas College, P.O. Box 2503, New Westminster, BC, Canada V3L 5B2.

Phagocytosis is a fundamental aspect of innate resistance against microbes, including fungi. In this study we investigated the significance of beta-glucan on the surfaces of zymosan particles, derived from Saccharomyces cerevisiae, during phagocytosis by RAW 264.7 macrophages. Phagocytosis was assessed in vitro by macrophage exposure to zymosan particles followed by cell staining and light microscopy. Macrophage ingestion of zymosan was dependent on cellular recognition of the particles' beta-glucans since laminarin, a soluble beta-glucan, inhibited phagocytosis in a concentration dependent manner when added to cell cultures. In contrast, the presence of another carbohydrate, mannan, had no effect on zymosan phagocytosis by cells. In addition we showed that LPS and dexamethasone had opposing effects on phagocytosis of zymosan. LPS significantly augmented ingestion while in contrast dexamethasone, like laminarin, suppressed it. The LPS-enhanced ingestion of zymosan was insensitive to the presence of laminarin in cell cultures, however dexamethasone partially ameliorated the effects of LPS on phagocytosis. Our findings confirm beta-glucan as an important ligand identified by macrophages and required for zymosan phagocytosis in naïve cells, but not in cells previously exposed to LPS.
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http://dx.doi.org/10.1016/j.intimp.2011.08.005DOI Listing
November 2011