Lipid compartments and lipid metabolism as therapeutic targets against coronavirus

Lipids perform a series of cellular functions, establishing cell and organelles’ boundaries, organizing signaling platforms, and creating compartments where specific reactions occur. Moreover, lipids store energy and act as secondary messengers whose distribution is tightly regulated. Disruption of lipid metabolism is associated with many diseases, including those caused by viruses. In this scenario, lipids can favor virus replication and are not solely used as pathogens’ energy source. In contrast, cells can counteract viruses using lipids as weapons. In this review, we discuss the available data on how coronaviruses profit from cellular lipid compartments and why targeting lipid metabolism may be a powerful strategy to fight these cellular parasites. We also provide a formidable collection of data on the pharmacological approaches targeting lipid metabolism to impair and treat coronavirus infection

Lipid droplet levels vary heterogeneously in response to simulated gastrointestinal stresses in different probiotic Saccharomyces cerevisiae strains

AbstractTo exert their therapeutic action, probiotic Saccharomyces cerevisiae strains must survive harsh digestive environments. Lipid droplets accumulate in cells which undergo stress-inducing situations, supposedly having a protective role. We assessed lipid droplet levels, either naturally accumulated or induced in response to digestive challenges, of probiotic strains S. boulardii, S. cerevisiae A-905, S. cerevisiae Sc47 and S. cerevisiae L11, and of non-probiotic strains S. cerevisiae BY4741 and S. cerevisiae BY4743. Strains 905 and Sc47 had lower and higher lipid droplet levels, respectively, when compared to the remaining strains, showing that higher accumulationof these neutral lipids is not a feature shared by all probiotic Saccharomyces strains. When submitted to simulated gastric or bile salts environments, lipid droplet levels increase in all tested probiotic strains, at least for one to the induced stresses, suggesting that lipid droplets participate in the protective mechanisms against gastrointestinal stresses in probiotic Saccharomyces yeasts

A New Fluorescence-Based Method Identifies Protein Phosphatases Regulating Lipid Droplet Metabolism

In virtually every cell, neutral lipids are stored in cytoplasmic structures called lipid droplets (LDs) and also referred to as lipid bodies or lipid particles. We developed a rapid high-throughput assay based on the recovery of quenched BODIPY-fluorescence that allows to quantify lipid droplets. The method was validated by monitoring lipid droplet turnover during growth of a yeast culture and by screening a group of strains deleted in genes known to be involved in lipid metabolism. In both tests, the fluorimetric assay showed high sensitivity and good agreement with previously reported data using microscopy. We used this method for high-throughput identification of protein phosphatases involved in lipid droplet metabolism. From 65 yeast knockout strains encoding protein phosphatases and its regulatory subunits, 13 strains revealed to have abnormal levels of lipid droplets, 10 of them having high lipid droplet content. Strains deleted for type I protein phosphatases and related regulators (ppz2, gac1, bni4), type 2A phosphatase and its related regulator (pph21 and sap185), type 2C protein phosphatases (ptc1, ptc4, ptc7) and dual phosphatases (pps1, msg5) were catalogued as high-lipid droplet content strains. Only reg1, a targeting subunit of the type 1 phosphatase Glc7p, and members of the nutrient-sensitive TOR pathway (sit4 and the regulatory subunit sap190) were catalogued as low-lipid droplet content strains, which were studied further. We show that Snf1, the homologue of the mammalian AMP-activated kinase, is constitutively phosphorylated (hyperactive) in sit4 and sap190 strains leading to a reduction of acetyl-CoA carboxylase activity. In conclusion, our fast and highly sensitive method permitted us to catalogue protein phosphatases involved in the regulation of LD metabolism and present evidence indicating that the TOR pathway and the SNF1/AMPK pathway are connected through the Sit4p-Sap190p pair in the control of lipid droplet biogenesis

Microglial phagolysosome dysfunction and altered neural communication amplify phenotypic severity in Prader-Willi Syndrome with larger deletion

Prader-Willi Syndrome (PWS) is a rare neurodevelopmental disorder of genetic etiology, characterized by paternal deletion of genes located at chromosome 15 in 70% of cases. Two distinct genetic subtypes of PWS deletions are characterized, where type I (PWS T1) carries four extra haploinsufficient genes compared to type II (PWS T2). PWS T1 individuals display more pronounced physiological and cognitive abnormalities than PWS T2, yet the exact neuropathological mechanisms behind these differences remain unclear. Our study employed postmortem hypothalamic tissues from PWS T1 and T2 individuals, conducting transcriptomic analyses and cell-specific protein profiling in white matter, neurons, and glial cells to unravel the cellular and molecular basis of phenotypic severity in PWS sub-genotypes. In PWS T1, key pathways for cell structure, integrity, and neuronal communication are notably diminished, while glymphatic system activity is heightened compared to PWS T2. The microglial defect in PWS T1 appears to stem from gene haploinsufficiency, as global and myeloid-specific Cyfip1 haploinsufficiency in murine models demonstrated. Our findings emphasize microglial phagolysosome dysfunction and altered neural communication as crucial contributors to the severity of PWS T1’s phenotype

Heme-Oxygenases during Erythropoiesis in K562 and Human Bone Marrow Cells

In mammalian cells, heme can be degraded by heme-oxygenases (HO). Heme-oxygenase 1 (HO-1) is known to be the heme inducible isoform, whereas heme-oxygenase 2 (HO-2) is the constitutive enzyme. Here we investigated the presence of HO during erythroid differentiation in human bone marrow erythroid precursors and K562 cells. HO-1 mRNA and protein expression levels were below limits of detection in K562 cells. Moreover, heme was unable to induce HO-1, at the protein and mRNA profiles. Surprisingly, HO-2 expression was inhibited upon incubation with heme. To evaluate the physiological relevance of these findings, we analyzed HO expression during normal erythropoiesis in human bone marrow. Erythroid precursors were characterized by lack of significant expression of HO-1 and by progressive reduction of HO-2 during differentiation. FLVCR expression, a recently described heme exporter found in erythroid precursors, was also analyzed. Interestingly, the disruption in the HO detoxification system was accompanied by a transient induction of FLVCR. It will be interesting to verify if the inhibition of HO expression, that we found, is preventing a futile cycle of concomitant heme synthesis and catabolism. We believe that a significant feature of erythropoiesis could be the replacement of heme breakdown by heme exportation, as a mechanism to prevent heme toxicity

Stromal-vascular fraction content and adipose stem cell behavior are altered in morbid obese and post bariatric surgery ex-obese women

Made available in DSpace on 2015-08-19T13:49:20Z (GMT). No. of bitstreams: 2 license.txt: 1914 bytes, checksum: 7d48279ffeed55da8dfe2f8e81f3b81f (MD5) sally_liechocki_etal_IOC_2015.pdf: 2915552 bytes, checksum: 8af3b1c114a5e8427115a01866e373f5 (MD5) Previous issue date: 2015Universidade Federal do Rio de Janeiro. Programa de Pós-Graduação em Clínica Médica. Rio de Janeiro, RJ, Brasil / Universidade Federal do Rio de Janeiro. Xerém em Biologia (Numpex-Bio). Duque de Caxias, RJ, Brasil / Instituto Nacional de Metrologia, Qualidade e Tecnologia (Inmetro). Diretoria de Programas. Programa de Engenharia. Duque de Caxias, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Imunofarmacologia. Rio de Janeiro, RJ, Brasil.Universidade Federal do Rio de Janeiro.Hospital Universitário Clementino Fraga Filho. Departamento de Nutrologia. Rio de Janeiro, RJ, Brasil.Universidade Federal do Rio de Janeiro.Hospital Universitário Clementino Fraga Filho. Serviço de Cirurgia Plástica. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Imunofarmacologia. Rio de Janeiro, RJ, Brasil.Universidade Federal do Rio de Janeiro. Programa de Pós-Graduação em Clínica Médica. Rio de Janeiro, RJ, Brasil / Instituto Nacional de Metrologia, Qualidade e Tecnologia (Inmetro). Diretoria de Programas. Programa de Bioengenharia. Duque de Caxias, RJ, Brasil.Universidade Federal do Rio de Janeiro. Programa de Pós-Graduação em Clínica Médica. Rio de Janeiro, RJ, Brasil / Universidade Federal do Rio de Janeiro. Xerém em Biologia (Numpex-Bio). Duque de Caxias, RJ, Brasil / Instituto Nacional de Metrologia, Qualidade e Tecnologia (Inmetro). Diretoria de Programas. Programa de Engenharia. Duque de Caxias, RJ, Brasil.Introduction: Subcutaneous adipose tissue is an interesting source of autologous stem cells with a fundamental role in the pathophysiology of obesity, metabolic syndromes and insulin resistance. We hypothesize that obesity could alter the stromal-vascular fraction (SVF) and adipose stem cell (ASCs) functions, which could compromise its regenerative behavior. Furthermore, we aimed to evaluate whether ASCs derived from post bariatric surgery ex-obese women maintain their functions in a similar fashion as do those from individuals who have never been obese. Methods: The SVF of subcutaneous adipose tissue from control (n = 6, body mass index – BMI - 27.5 ± 0.5 kg/m2), obese (n = 12, BMI 46.2 ± 5.1 kg/m2) and post bariatric surgery ex-obese (n = 7, initial BMI 47.8 ± 1.3 kg/m2; final BMI 28.1 ± 1.1 kg/m2) women were isolated and evaluated by flow cytometry. ASCs were tested for lipid accumulation by perilipin, adipose differentiation-related protein (ADRP) and Oil Red O staining after adipogenic stimulus. The cytokines secreted by the ASCs and after lipid accumulation induction were also evaluated. Results: The subcutaneous adipose tissue of obese and post bariatric surgery ex-obese women was enriched in pericytes (p = 0.0345). The number of supra-adventitial cells was not altered in the obese patients, but it was highly enriched in the post bariatric surgery ex-obese women (p = 0.0099). The ASCs of the post bariatric surgery ex-obese patients secreted more MCP-1 (monocyte chemoattractant protein-1; p = 0.0078). After lipid accumulation induction, the ASCs of the patients in all groups secreted less IL-6 than the ASCs with no adipogenic stimulus (p < 0.0001). Obese ASCs with lipid accumulation secreted the highest amount of IL-6 (p < 0.001) whereas the ASCs from the controls secreted the highest amount of adiponectin (p < 0.0001). The ASCs from the post bariatric surgery ex-obese patients showed the highest levels of lipid accumulation whereas those from the obese women had the lowest levels (p < 0.0001). Conclusions: SVF content and ASC behavior are altered in the subcutaneous adipose tissue of morbid obese women; these changes are not completely restored after bariatric surgery-induced weight loss. The cellular alterations described in this study could affect the regenerative effects of adipose stem cells. Further investigations are required to avoid jeopardizing the development of autologous stem cell-based therapies

Lipid Droplets accumulate in the hypothalamus of mice and humans with and without metabolic diseases

BACKGROUND: In peripheral tissues, the lipid droplet (LD) organelle links lipid metabolism, inflammation and insulin resistance. Little is known about the brain LDs. OBJECTIVES: We hypothesised that hypothalamic LDs would be altered in metabolic diseases. METHODS: We used immunofluorescence for the specific LD protein, PLIN2, as the marker to visualize and quantify LDs. RESULTS: LDs were abundant in the hypothalamic third ventricle (3V) wall layer with similar heterogeneous distributions between control mice and humans. The LD content was enhanced by HFD in both WT and in low-density lipoprotein receptor deficient (Ldlr -/- HFD) mice. Strikingly, we observed a lower LD amount in T2DM patients when compared with non-T2DM, patients. CONCLUSIONS: LDs accumulate in the normal hypothalamus, with similar distributions in human and mouse. Moreover, metabolic diseases differently modify LD content in mouse and human. Our results point hypothalamic LDs accumulation as an important target to the study of metabolism