👤 Delia Ramírez

Alzheimer's disease (AD) is a neurodegenerative disorder (NDD) associated with the accumulation of beta-amyloid plaques (βA), oxidative stress, and a decrease in cholinergic activity among other pathologies. Given the limitations of current treatments, multitarget strategies present a promising alternative. In this study we prioritized six AD-related protein targets: acetylcholinesterase (AChE), beta-secretase 1 (BACE-1), cannabinoid receptor type 2 (CB2), glycogen synthase kinase 3 beta (GSK-3β), monoamine oxidase A (MAO-A), and the neuronal acetylcholine receptor subunit alpha-7 (nAChR7). Ligand- and structure-based virtual screening methods were applied to identify potential multitarget directed ligands (MTDLs), reducing an initial database of 14 million compounds to 21 early stage candidate MTDLs, that were tested experimentally against AChE, BACE-1, GSK-3β, MAO-A, nAChR7, and the additional targets BChE and MAO-B; however, CB2 could not be experimentally assessed. Among the tested molecules, PJ17 exhibited a dual-target profile with submicromolar activity against AChE and GSK-3β, while PJ11 showed notable MAO-B inhibition. Molecular dynamics simulations revealed key common interactions between PJ17 and those targets providing insights into its potential for further hit-to-lead optimization. In addition, PJ17 showed a safe profile in cellular primary culture suggesting its use as a template to design multitarget drugs against AD. Show less

Gene-environment interaction studies are emerging as a promising tool to shed light on the reasons for the rapid increase in excess body weight (overweight and obesity). We aimed to investigate the influence of several polymorphisms on excess weight in Spanish children according to a short- and long-term exposure to bisphenols and parabens, combining individual approach with the joint effect of them. This case-control study included 144 controls and 98 cases children aged 3-12 years. Thirty SNPs in genes involved in obesity-related pathways, xenobiotic metabolism and hormone systems were genotyped using the GSA microchip technology and qPCRs with Taqman® probes. Levels of bisphenols and parabens in urine and hair were used to assess short- and long-term exposure, respectively, via UHPLC-MS/MS system. LEPR rs9436303 was identified as a relevant risk variant for excess weight (OR Show less

Lipopolysaccharide binding proteins (LBPs) and bactericidal permeability increasing proteins (BPIs) play significant roles in the immune response of vertebrates against bacterial pathogens. These soluble proteins produced by immune cells, specifically interact with and bind to bacterial lipopolysaccharides (LPS), with BPIs also displaying antibacterial activity. In Argopecten purpuratus scallop larvae resistant to Vibrio bivalvicida VPAP30, we identified a significant overexpression of a transcript displaying molecular features of an LBP/BPI protein, both before and after infection. Therefore, in the present work we aimed to understand the role of this novel LBP/BPI, named ApLBP/BPI3, in the scallop resistance to this Vibrio. The ApLBP/BPI3 open reading frame encodes a putative protein of 506 amino acids, with a molecular weight 56.78 kDa. The protein contains a C-terminal domain of 403-amino acid that, after theorical cleavage, displays a soluble form of 44.99 kDa, featuring two BPI/LBP/CETP domains, an apolar binding pocket, a single disulfide bond and a BPI dimerization interface. Phylogenetic analysis reveals high similarity between ApLBP/BPI3 and other mollusk LBP/BPI proteins. Aplbp/bpi3 transcripts were constitutively and highly expressed in hemocytes, gills, mantle, and digestive gland tissues, and were induced following VPAP30 infection in scallop larvae and adult hemocytes. We characterized ApLBP/BPI3 protein using a polyclonal antibody against a synthetic peptide. ApLBP/BPI3 was secreted to the media by infected cultured hemocytes, detected by ELISA. ApLBP/BPI3 was spotted inside non-infected hemocytes, bound to the cell wall of V. bivalvicida after in vitro hemocyte infection, and coating the gills and mantle epithelial barriers before and after an in vivo immune challenge, with stronger detection after VPAP30 injection, detected by immunofluorescence. Infected scallop larvae showed increased ApLBP/BPI3 levels, with slightly higher production in resistant larvae, determined by Western blot. Finally, silencing the Aplbp/bpi3 transcript through RNA interference and and subsequently infecting scallop juveniles with an LD50 of V. bivalvicida resulted in 100 % mortality. Altogether, results demonstrate the essential role of this immune effector in the resistance of A. purpuratus. Show less

Recent findings relate obesity to inflammation in key hypothalamic areas for body weight control. Hypothalamic inflammation has also been related to oxidative stress. Palmitic acid (PA) is the most abundant free fatty acid found in food, and in vitro studies indicate that it triggers a pro-inflammatory response in the brain. Melanocortins are neuropeptides with proven anti-inflammatory and neuroprotective action mediated by melanocortin receptor 4 (MC4R), but little is known about the effect of melanocortins on oxidative stress. The aim of this study was to investigate whether melanocortins could alleviate oxidative stress induced by a high fat diet (HFD) model. We found that NDP-MSH treatment decreased PA-induced reactive oxygen species production in astrocytes, an effect blocked by the MC4R inhibitor JKC363. NDP-MSH abolished nuclear translocation of Nrf2 induced by PA and blocked the inhibitory effect of PA on superoxide dismutase (SOD) activity and glutathione levels while it also per se increased activity of SOD and γ-glutamate cysteine ligase (γ-GCL) antioxidant enzymes. However, HFD reduced hypothalamic MC4R and brain derived neurotrophic factor mRNA levels, thereby preventing the neuroprotective mechanism induced by melanocortins. Show less

α-Melanocyte stimulating hormone (α-MSH) is a melanocortin which exerts potent anti-inflammatory and anti-apoptotic effects. Melanocortin 4 receptors (MC4R) are abundantly expressed in the brain and we previously demonstrated that [Nle(4), D-Phe(7)]melanocyte-stimulating hormone (NDP-MSH), an α-MSH analogue, increased expression of brain derived-neurotrophic factor (BDNF), and peroxisome proliferator-activated receptor-γ (PPAR-γ). We hypothesized that melanocortins could affect striatal cell survival through BDNF and PPAR-γ. First, we determined the expression of these factors in the striatum. Acute intraperitoneal administration (0.5 mg/kg) of α-MSH increased the levels of BDNF mRNA in rat striatum but not in rat cerebral cortex. Also, protein expression of PPAR-γ and MC4R was increased by acute treatment with α-MSH in striatum but not in cortex. No changes were observed by 48 h treatment. Next, we evaluated melanocortins effect on neuron and glial survival. 3-nitropropionic acid (3-NP), which is known to induce striatal degeneration, was used to induce cell death in the rat striatal cell line ST14A expressing mutant human huntingtin (Q120) or in ST14A cells expressing normal human huntingtin (Q15), in primary cultured astrocytes, and in BV2 cells. NDP-MSH protected Q15 cells, astrocytes and BV2 cells from death by 3-NP whereas it did not fully protect Q120 cells. Protection of Q15 cells and astrocytes was blocked by a MC4R specific inhibitor (JKC-363) and a PPAR-γ antagonist (GW9662). The BDNF receptor antagonist (ANA-12) abolished NDP-MSH protective effect in astrocytes but not in Q15 cells. We demonstrate for the first time that melanocortins, acting through PPAR-γ and BDNF, protect neurons and glial cells from 3-NP toxicity. Show less

Next to applications in fermentations, Lactobacillus plantarum is recognized as a food spoilage organism, and its dispersal from biofilms in food processing environments might be implicated in contamination or recontamination of food products. This study provides new insights into biofilm development by L. plantarum WCFS1 through comparative analysis of wild type and mutants affected in cell surface composition, including mutants deficient in the production of Sortase A involved in the covalent attachment of 27 predicted surface proteins to the cell wall peptidoglycan (ΔsrtA) and mutants deficient in the production of capsular polysaccharides (CPS1-4, Δcps1-4). Surface adhesion and biofilm formation studies revealed none of the imposed cell surface modifications to affect the initial attachment of cells to polystyrene while biofilm formation based on Crystal Violet (CV) staining was severely reduced in the ΔsrtA mutant and significantly increased in mutants lacking the cps1 cluster, compared to the wild-type strain. Fluorescence microscopy analysis of biofilm samples pointed to a higher presence of extracellular DNA (eDNA) in cps1 mutants and this corresponded with increased autolysis activity. Subsequent studies using Δacm2 and ΔlytA derivatives affected in lytic behaviour revealed reduced biofilm formation measured by CV staining, confirming the relevance of lysis for the build-up of the biofilm matrix with eDNA. Show less

Regulation of liver X receptors (LXRs) is essential for cholesterol homeostasis and inflammation. The present study was conducted to determine whether oleic acid (OA) could regulate mRNA expression of LXRα and LXRα-regulated genes and to assess the potential promotion of oxidative stress by OA in neutrophils. Human neutrophils were treated with OA at different doses and LXR target gene expression, oxidative stress production, lipid efflux and inflammation state were analyzed. We describe that mRNA synthesis of both LXRα and ABCA1 (a reverse cholesterol transporter) was induced by OA in human neutrophils. This fatty acid enhanced the effects of LXR ligands on ABCA1 and LXR expression, but it decreased the mRNA levels of sterol regulatory element-binding protein 1c (a transcription factor that regulates the synthesis of triglycerides). Although OA elicited a slight oxidative stress in the short term (15-30 min) in neutrophils, it is unlikely that this is relevant for the modulation of transcription in our experimental conditions, which involve longer incubation time (i.e., 6 h). Of physiological importance is our finding that OA depresses intracellular lipid levels and that markers of inflammation, such as ERK1/2 and p38 mitogen-activated protein kinase phosphorylation, were decreased by OA treatment. In addition, 200 μM OA reduced the migration of human neutrophils, another marker of the inflammatory state. However, OA did not affect lipid peroxidation induced by pro-oxidant agents. This work presents for the first time evidence that human neutrophils are highly sensitive to OA and provides novel data in support of a protective role of this monounsaturated acid against the activation of neutrophils during inflammation. Show less

Liver X receptors (LXRs) are ligand-activated members of the nuclear receptor superfamily that regulate the expression of genes involved in lipid metabolism and inflammation, although their role in inflammation and immunity is less well known. It has been reported that oxysterols/LXRs may act as anti-inflammatory molecules, although opposite actions have also been reported. In this study, we investigated the effect of platelet-activating factor (PAF), a proinflammatory molecule, on LXRα signalling in human neutrophils. We found that PAF exerted an inhibitory effect on mRNA expression of TO901317-induced LXRα, ATP-binding cassette transporter A1, ATP-binding cassette transporter G1, and sterol response element binding protein 1c. This negative action was mediated by the PAF receptor, and was dependent on the release of reactive oxygen species elicited by PAF, as it was enhanced by pro-oxidant treatment and reversed by antioxidants. Current data also support the idea that PAF induces phosphorylation of the LXRα molecule in an extracellular signal-regulated kinase 1/2-mediated fashion. These results suggest that a possible mechanism by which PAF exerts its proinflammatory effect is through the downregulation of LXRα and its related genes, which supports the notion that LXRα ligands exert a modulatory role in the neutrophil-mediated inflammatory response. Show less

Circulatory metabolites are important biomarkers for many diseases, especially metabolic disorders. The biological mechanism regulating circulatory levels of metabolites remains incompletely understood. Focusing on the liver as the central organ controlling metabolic homeostasis, we investigated the potential function of nine polymorphisms associated with serum metabolomic traits in a recent GWAS. The mRNA levels of the associated genes were measured by real-time PCR and correlated with genotypes in normal liver tissue (n=42). Genotype and mRNA data were also correlated with total hepatic lipid content (HLC). Our findings were also compared with the previously published gene expression quantitative traits loci (eQTL) data in the liver. We found that seven out of nine genes were highly expressed in hepatic tissue, while expression of four genes was significantly or marginally associated with genotypes (SPTLC3 vs rs168622, P=.002; ACADS vs rs2014355, P=.016; PLEKHH1 vs rs7156144, P=.076; ACADL vs rs2286963, P=.068). The SNP rs168622 at the SPTLC3 locus was also significantly correlated with HLC (P=.02). HLC was significantly correlated with FADS1 (r=-0.45; P=.003) and ETFDH (r=0.33; P=.037) expression. When compared with published eQTL data, SNPs in SPTLC3, ACADS, ELOVL2 and FADS1 were also in strong linkage disequilibrium (R(2)≥0.41, D'≥0.96) with eQTLs significantly affecting expression of these genes (P≤1.74×10(-5)). Our study suggests that genetic variants affecting serum metabolites levels may play a functional role in the liver. This may help elucidate the mechanism by which genetic variants are involved in metabolic diseases. Show less

Liver X receptors (LXRs) are ligand-activated transcription factors of the nuclear receptor superfamily. They play important roles in controlling cholesterol homeostasis and as regulators of inflammatory gene expression and innate immunity, by blunting the induction of classical pro-inflammatory genes. However, opposite data have also been reported on the consequences of LXR activation by oxysterols, resulting in the specific production of potent pro-inflammatory cytokines and reactive oxygen species (ROS). The effect of the inflammatory state on the expression of LXRs has not been studied in human cells, and constitutes the main aim of the present work. Our data show that when human neutrophils are triggered with synthetic ligands, the synthesis of LXRα mRNA became activated together with transcription of the LXR target genes ABCA1, ABCG1 and SREBP1c. An inflammatory mediator, 15-deoxy-Δ(12,14)-prostaglandin J(2) (15dPGJ(2)), hindered T0901317-promoted induction of LXRα mRNA expression together with transcription of its target genes in both neutrophils and human macrophages. This down-regulatory effect was dependent on the release of reactive oxygen species elicited by 15dPGJ(2), since it was enhanced by pro-oxidant treatment and reversed by antioxidants, and was also mediated by ERK1/2 activation. Present data also support that the 15dPGJ(2)-induced serine phosphorylation of the LXRα molecule is mediated by ERK1/2. These results allow to postulate that down-regulation of LXR cellular levels by pro-inflammatory stimuli might be involved in the development of different vascular diseases, such as atherosclerosis. Show less

Hypertrophic cardiomyopathy (HCM) is an autosomal dominant disease, which may afflict as many as 1 in 500 subjects (0.2%), being probably the most common hereditary cardiovascular disease and the most common cause of sudden cardiac death (SCD). Hypertrophic cardiomyopathy is characterized by the presence of unexplained left ventricular hypertrophy (in absence of hypertension, valvular disease, etc), which is usually asymmetric and involves the ventricular septum. Molecular genetic studies have identified eleven genes that code proteins of the sarcomere that are associated with the HCM; the beta-myosin heavy chain gene (MYH7), alpha-myosin heavy chain (MYH6), cardiac troponin T (TNNT2); cardiac troponin C (TNNC1), alpha-tropomyosin (TPM1), myosin binding protein-C (MYBPC3), cardiac troponin (TNNI3), essential and regulatory light chain genes (MYL3 and MYL2, respectively), cardiac alpha-actin gene (ACTC) and titin (TTN). The objective of this paper is the revision of the current state of the knowledge on (1) the organization and mutations of the HCM causing genes and their proteins and (2) the animal models developed for the study of the genes, mutations and proteins in the hypertrophic cardiomyopathy. Show less