Karen Fuenzalida - Academia.edu (original) (raw)

Papers by Karen Fuenzalida

bioRxiv (Cold Spring Harbor Laboratory), Mar 17, 2021

The biomedical potential of the edible red seaweed Agarophyton chilense (former Gracilaria chilen... more The biomedical potential of the edible red seaweed Agarophyton chilense (former Gracilaria chilensis) has not been explored. Red seaweeds are enriched in polyunsaturated fatty acids and eicosanoids, which are known natural ligands of the PPARγ nuclear receptor. PPARγ is the molecular target of thiazolidinediones (TZDs), drugs used as insulin sensitizers to treat type 2 diabetes mellitus. TZDs medical use is limited due to undesired side effects, the fact that it has triggered the search for partial agonists without the TZDs side effects. We produced A.chilense oleoresin (Gracilex®) that induces the activation of PPARγ without inducing adipocyte differentiation, similar to PPARγ partial agonists. In a model of high-fat diet-induced obesity in male mice, we showed that treatment with Gracilex® improves insulin sensitivity, normalizing altered glucose and insulin parameters. Gracilex® was enriched in palmitic acid, arachidonic acid, oleic acid, and lipophilic antioxidants such as ß-carotene and tocopherols. Gracilex® possesses antioxidant activity in vitro (CUPRAC) and increased the antioxidant capacity in vivo in Caenorhabditis elegans. These findings support the idea that Gracilex® is an excellent source of healthy lipids targeting PPARγ with antioxidant activity and a high nutraceutical value.

Metabolites

Phenylketonuria (PKU) is an autosomal recessive inborn error of metabolism where high phenylalani... more Phenylketonuria (PKU) is an autosomal recessive inborn error of metabolism where high phenylalanine (Phe) concentrations cause irreversible intellectual disability that can be prevented by newborn screening and early treatment. Evidence suggests that PKU subjects not adherent to treatment could be at risk of insulin resistance (IR). We studied how Phe concentrations (PheCs) relate to IR using machine learning (ML) and derived potential biomarkers. In our cross-sectional study, we analyzed subjects with neonatal diagnoses of PKU, grouped as follows: 10 subjects who adhered to treatment (G1); 14 subjects who suspended treatment (G2); and 24 control subjects (G3). We analyzed plasma biochemical variables, as well as profiles of amino acids and acylcarnitines in dried blood spots (DBSs). Higher PheCs and plasma insulin levels were observed in the G2 group compared to the other groups. Additionally, a positive correlation between the PheCs and homeostatic measurement assessments (HOMA-IR...

Journal of Biological Chemistry, 2007

Peroxisome proliferator-activated receptor γ (PPARγ) has been proposed as a therapeutic target fo... more Peroxisome proliferator-activated receptor γ (PPARγ) has been proposed as a therapeutic target for neurodegenerative diseases because of its anti-inflammatory action in glial cells. However, PPARγ agonists preventβ-amyloid (Aβ)-induced neurodegeneration in hippocampal neurons, and PPARγ is activated by the nerve growth factor (NGF) survival pathway, suggesting a neuroprotective anti-inflammatory independent action. Here we show that the PPARγ agonist rosiglitazone (RGZ) protects hippocampal and dorsal root ganglion neurons against Aβ-induced mitochondrial damage and NGF deprivation-induced apoptosis, respectively, and promotes PC12 cell survival. In neurons and in PC12 cells RGZ protective effects are associated with increased expression of the Bcl-2 anti-apoptotic protein. NGF-differentiated PC12 neuronal cells constitutively overexpressing PPARγ are resistant to Aβ-induced apoptosis and morphological changes and show functionally intact mitochondria and no increase in reactive oxy...

NEURONS AND INDUCES MITOCHONDRIAL STABILIZATION AND PROTECTION AGAINST OXIDATIVE STRESS AND APOPT... more NEURONS AND INDUCES MITOCHONDRIAL STABILIZATION AND PROTECTION AGAINST OXIDATIVE STRESS AND APOPTOSIS. Karen Fuenzalida, Rodrigo Quintanilla, Patricio Ramos, Daniela Piderit, Rodrigo A Fuentealba, Gabriela Martinez, Nibaldo C Inestrosa and Miguel Bronfman. From the Centro de Regulación Celular y Patologia “Joaquín V. Luco” (CRCP), and Millennium Institute for Fundamental and Applied Biology, Department of Cellular and Molecular Biology, Facultad de Ciencias Biológicas, P.Universidad Católica de Chile, Santiago, Chile. Running Title: PPAR gamma up-regulates Bcl-2 anti-apoptotic protein Address correspondence to: Miguel Bronfman, Department of Cellular and Molecular Biology, Facultad de Ciencias Biológicas, P.Universidad Católica de Chile, Alameda 340, Santiago, Chile, Tel. 56 2 686 2833; E-Mail: mbronfman@bio.puc.cl

Peroxisome proliferator-activated receptor (PPAR) has been proposed as a therapeutic target for n... more Peroxisome proliferator-activated receptor (PPAR) has been proposed as a therapeutic target for neurodegenerative diseases because of its anti-inflammatory action in glial cells. However, PPAR agonists prevent-amyloid (A)-induced neurodegeneration in hippocampal neurons, and PPAR is activated by the nerve growth factor (NGF) survival pathway, suggesting a neuroprotective anti-inflammatory independent action. Here we show that the PPAR agonist rosiglitazone (RGZ) protects hippocampal and dorsal root ganglion neurons against A-induced mitochondrial damage and NGF deprivation-induced apoptosis, respectively, and promotes PC12 cell survival. In neurons and in PC12 cells RGZ protective effects are associated with increased expression of the Bcl-2 anti-apoptotic protein. NGF-differentiated PC12 neuronal cells constitutively overexpressing PPAR are resistant to A-induced apoptosis and morphological changes and show functionally intact mitochondria and no increase in reactive oxygen species...

Elevation of branched-chain amino acids (BCAAs) in biological fluids indicates a deficiency in th... more Elevation of branched-chain amino acids (BCAAs) in biological fluids indicates a deficiency in the branched-chain ketoacid dehydrogenase complex, which causes maple syrup urine disease (MSUD). Detection of increased levels of alloisoleucine confirms the diagnosis, while routine monitoring of leucine concentration is crucial for preventing metabolic decompensation and neurological dysfunction. In the metabolic center at Universidad de Chile, we have confirmed and monitored more than fifty MSUD patients in the last 20 years. Most diagnoses were made by clinical and sibling diagnosis, as MSUD is not included in the Chilean national newborn screening program. Shortening diagnosis time has a fundamental impact on the outcome of patients, therefore we focused on implementing detection of BCAAs in dried blood spot by liquid chromatography mass spectrometry (LC-MSMS) for disease confirmation as well as for biochemical monitoring. Retrospective analysis of samples from 9 diagnosed MSUD patients were performed; BCAAs values were determined via MSMS and LC-MSMS conducted in parallel. Leucine and alloisoleucine levels were positively correlated with patient's diagnosis age. Alloisoleucine was significatively elevated as early as 24 hr after birth. A predictable variation in BCAAs levels after nutritional intervention among diagnosed MSUD patients was found.

JIMD reports, Jan 30, 2017

Phenylketonuria (PKU, OMIM 261600) is an autosomal recessive disease, caused by mutations in the ... more Phenylketonuria (PKU, OMIM 261600) is an autosomal recessive disease, caused by mutations in the Phenylalanine Hydroxylase (PAH) gene situated in chromosome 12q22-q24.2. This gene has 13 exons. To date, 991 mutations have been described. The genotype is one of the main factors that determine the phenotype of this disease. Characterize PKU genotype and phenotype seen in Chilean PKU patients. We studied the PAH gene by restriction fragment length polymorphism (RFLP) and/or sequencing techniques to identify pathogenic mutations in 71 PKU subjects. We classified the phenotype according to Guldberg predicted value. We identified 26 different mutations in 134 of the 142 alleles studied (94.4%), 88.7% of the subjects had biallelic pathogenic mutations while 11.3% had only one pathogenic mutation identified. Compound heterozygous represented 85.9% of the cases. Exon 7 included the majority of mutations (26.9%) and 50% of mutations were missense. The most frequent mutations were c.1066-11G &...

The Journal of Biological Chemistry, Jan 4, 2005

Journal of Neurochemistry, 2003

Biological Research, 2013

Phototransduction, the mechanism underlying the electrical response to light in photoreceptor cel... more Phototransduction, the mechanism underlying the electrical response to light in photoreceptor cells, has been thoroughly investigated in Drosophila melanogaster, an essential model in signal transduction research. These cells present a highly specialized photosensitive membrane consisting of thousands of microvilli forming a prominent structure termed a rhabdomere. These microvilli encompass the phototransduction proteins, most of which are transmembrane and exclusively rhabdomeric. Rhabdomere membrane lipids play a crucial role in the activation of the transient receptor potential ionic channels (TRP and TRPL) responsible for initiating the photoresponse. Despite its importance, rhabdomere lipid composition has not been established. We developed a novel preparation enriched in rhabdomere membranes to perform a thorough characterization of the lipidomics of Drosophila rhabdomeres. Isolated eyes (500) were homogenized and subjected to a diff erential centrifugation protocol that generates a fraction enriched in rhabdomere membrane. Lipids extracted from this preparation were identifi ed and quantifi ed by gas chromatography coupled to mass spectrometry. We found an abundance of low sterol esters (C16:0, C18:0), highly abundant and diverse triglycerides, free fatty acids, a moderate variety of mono and diacyglycerols (C:16:0, 18:0, C18:1) and abundant phospholipids (principally C18:2). This preparation opens a new avenue for investigating essential aspects of phototransduction.

Journal of Biological …, 2007

... Karen Fuenzalida, Rodrigo Quintanilla, Patricio Ramos, Daniela Piderit, Rodrigo A Fuentealba,... more ... Karen Fuenzalida, Rodrigo Quintanilla, Patricio Ramos, Daniela Piderit, Rodrigo A Fuentealba, Gabriela Martinez, Nibaldo C Inestrosa and Miguel ... Department of Cellular and Molecular Biology, Facultad de Ciencias Biológicas, P.Universidad Católica de Chile, Santiago, Chile. ...

Journal of Clinical Medicine, 2021

Treatment and follow-up in Hereditary Tyrosinemia type 1 (HT-1) patients require comprehensive cl... more Treatment and follow-up in Hereditary Tyrosinemia type 1 (HT-1) patients require comprehensive clinical and dietary management, which involves drug therapy with NTBC and the laboratory monitoring of parameters, including NTBC levels, succinylacetone (SA), amino acids, and various biomarkers of liver and kidney function. Good adherence to treatment and optimal adjustment of the NTBC dose, according to clinical manifestations and laboratory parameters, can prevent severe liver complications such as hepatocarcinogenesis (HCC). We analyzed several laboratory parameters for 15 HT-1 patients over one year of follow-up in a cohort that included long-term NTBC-treated patients (more than 20 years), as well as short-term patients (one year). Based on this analysis, we described the overall adherence by our cohort of 70% adherence to drug and dietary treatment. A positive correlation was found between blood and plasma NTBC concentration with a conversion factor of 2.57. Nonetheless, there was...

XXVI Brazilian Congress on Biomedical Engineering, 2019

Nonalcoholic fatty liver disease (NAFLD) is characterized by the accumulation of intracellular fa... more Nonalcoholic fatty liver disease (NAFLD) is characterized by the accumulation of intracellular fatty acids in the liver. The only method to confirm the stage of this disease is the biopsy, but it is invasive and risky to patients. The idea of defining a classifier using magnetic resonance spectroscopy (MRS) emerges due to the need to find a way to replace biopsy with a non-invasive method that can classify NAFLD based on the chemical structure of fatty acids stored in the liver. The purpose of this study is to investigate and compare the composition of fatty acids to the metabolites signals in MRS in NAFLD mice liver at 2 time-point during the progression of the disease. A group of C57BL/6 mice was fed with high-fat diet for one month (N = 8) and for three months (N = 6). First, we made a histological analysis to the liver. Then, we analysed the fatty acids with gas chromatography (GC) and MRS. As a result, the histological analysis showed the progression of fat content, and the GC ...

Peroxisome proliferator-activated receptor γ (PPARγ), a member of the nuclear receptor superfamil... more Peroxisome proliferator-activated receptor γ (PPARγ), a member of the nuclear receptor superfamily, is subject to considerable interest because of its role in adipocyte differentiation, metabolic control, and anti-inflammatory action. PPARγ research in brain cells is presently focused on glial PPARγ because of its potential as a pharmacological target in the treatment of neurodegenerative diseases with an inflammatory component. In neurons PPARγ function is far from clear, and PPARγ agonist-dependent and -independent effects on cell survival or differentiation have been reported. We used PC12 cells, widely used to study neuronal signaling, such as nerve growth factor (NGF)-induced differentiation and survival or epidermal growth factor-dependent cell proliferation to dissect the possible involvement of PPARγ in these pathways. We show that NGF but not epidermal growth factor increases the transcriptional activity of PPARγ, and modulates the expression of this transcription factor. B...

American Journal of Medical Genetics Part C: Seminars in Medical Genetics

We report the case of a 17‐year‐old girl with Tyrosinemia type 1a who carried a planned pregnancy... more We report the case of a 17‐year‐old girl with Tyrosinemia type 1a who carried a planned pregnancy to term while being under 2‐(2‐nitro‐4‐trifluoromethylbenzoyl)‐1,3‐cyclohexanedione (NTBC, nitisinone) treatment and a tyrosine‐ and phenylalanine‐restricted diet. She was on treatment since 2 months of age with poor metabolic control prior to her pregnancy (tyrosine 838 ± 106 umol/L). NTBC and a low tyrosine and phenylalanine diet were continued during her pregnancy. She unfortunately suffered from urinary tract infection and anemia during her pregnancy, with median plasma tyrosine and phenylalanine levels of 613 ± 106 umol/L (200–400 umol/L) and 40.2 ± 8 umol/L (35–90 umol/L), respectively. After 40 weeks of gestation, the patient gave birth to a healthy boy, with no adverse effects related to the use of NTBC. The newborn presented with a transitory elevation of plasma tyrosine levels and normal phenylalanine, methionine, and succinylacetone levels. By 12 months of age, the child was determined to have normal psychomotor development. At 20 months old, he was diagnosed with a mild developmental delay; however, global cognitive evaluation with the Wechsler Intelligence Scale for Children (WISC) test at 5 years old showed normal performance. Here, we discuss one of the few reported cases of nitisinone treatment during pregnancy and demonstrate a lack of teratogenicity and long‐term cognitive disabilities.

Biotechnology for Biofuels

Background: One of the major problems in the production of lipids for biotechnological purposes u... more Background: One of the major problems in the production of lipids for biotechnological purposes using microalgae is maintaining a high productivity of these molecules without reducing cellular biomass. High production rates are usually obtained by cultivating microalgae under different stress conditions. However, many of these changes usually result in lower biomass productivity. Therefore, the optimization of the culture conditions and genetic modification techniques in these organisms is needed to generate robust new strains for profitable economic use. Results: In this work, we describe a new strategy for random mutation of genomic DNA in the microalgae Nannochloropsis oceanica by insertion of a Transposome complex Tn5. This complex contains an antibiotic-resistance cassette commanded by a CMV viral promoter that allows high efficiency of transformation and the generation of mutants. This strategy, complemented with a large-scale identification and selection system for mutants, such as flow cytometry with cell selection, allowed us to obtain clonal cultures of mutants with altered phenotypes in the accumulation of intracellular lipids. The characterization of some of these mutants uncovered new genes that are likely to be involved in the regulation of lipid synthesis, revealing possible cellular responses that influence the intracellular homeostasis of lipids. Conclusion: The strategies proposed here are easy to implement in different types of microalgae and provide a promising scenario for improving biotechnological applications.