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Medizinische Universität Graz

Dagmar Kratky, PhD:

 

Role of intracellular lipid hydrolases in lipid and energy metabolism in placenta and fetus

Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging, Chair of Molecular Biology and Biochemistry, Medical University of Graz, Neue Stiftingtalstraße 6/6, A-8010 Graz;
phone: +43-316-385 71965, fax: +43-316-385 79615, ✉ e-mail

Keywords:

 

Lipid metabolism, lipases, atherosclerosis, inflammation, lipid signaling, leukocytes, diabetes, placenta

Research interest:

 

Intracellular lipid droplet formation, neutral lipid hydrolysis, and lipid catabolism are tightly regulated processes, which involve intracellular hydrolases, enzymes involved in lipid biosynthesis, and regulatory proteins. Excessive lipid storage in lipid droplets is central to the pathogenesis of prevalent metabolic diseases, such as obesity, diabetes, and atherosclerosis. The research interests of our group focus on lipid and energy metabolism in non-adipose tissues and cells. Over the past years, we concentrated our efforts on the consequences of lipase deficiency on the regulation of lipid and energy metabolism [1, 2]. We utilize transgenic and knockout mouse models with loss or overexpression of lipases to investigate the impact of the respective enzymes on systemic lipid and energy metabolism and atherogenesis. In addition, we are interested in cell and tissue autonomous functions of the respective enzymes. The role of lipases in lipid metabolism and inflammation in the placenta and the fetus are incompletely understood. We have previously reported on lipase activities in human and murine placenta with extracellular lipases (lipoprotein lipase, endothelial lipase) being involved [3]. The role of intracellular lipases, however, has not been addressed. We hypothesize that loss of adipose triglyceride lipase, hormone-sensitive lipase, monoglyceride lipase, and lysosomal acid lipase affects lipid and / or energy metabolism in the placenta and the fetus, thereby leading to alterations in cells (e. g. macrophages) and tissues (e. g. placenta).

 

 

Illustrations:

 

Fig. 1: Immunohistochemistry in human placenta: pronounced expression of MGL in trophoblasts (maternal side) and endothelium (fetal side) (unpublished).

References:      

  1. Radović B, Vujić N, Leopold C, Schlager S, Goeritzer M, Patankar JV, Korbelius M, Kolb D, Reindl J, Wegscheider M, Tomin T, Birner-Gruenberger R, Schittmayer M, Groschner L, Magnes C, Diwoky C, Frank S, Steyrer E, Du H, Graier WF, Madl T, Kratky D: Lysosomal acid lipase regulates VLDL synthesis and insulin sensitivity in mice. Diabetologia, 2016; 59(8): 1743–1752
  2. Chandak PG, Radovic B, Aflaki E, Kolb D, Buchebner M, Fröhlich E, Magnes C, Sinner F, Haemmerle G, Zechner R, Tabas I, Levak-Frank S, Kratky D: Efficient phagocytosis requires triacylglycerol hydrolysis by adipose triglyceride lipase.. J Biol Chem, 2010; 285(26): 20192–20201.    
  3. Lindegaard ML, Olivecrona G, Christoffersen C, Kratky D, Hannibal J, Petersen BL, Zechner R, Damm P, Nielsen LB: Endothelial and lipoprotein lipases in human and mouse placenta. J Lipid Res, 2005; 46(11): 2339–2446.   

 

Collaborations within the DP-iDP:

  • G. Desoye will assist the students in detailed analysis of endothelial cell function such as proliferation / cell-cycle assays and train students in the isolation of placental endothelial cells of mutant mouse models.  
  • C. Wadsack will help the students with ex vivo placental perfusion assays of mutant mouse models.
  • M. Gauster will train the students in immunhistochemical analysis of placental tissue.
  • Á. Heinemann will train the students in leukocyte–endothelial interaction.
  • G. Marsche will train the students in (patho)physiology of lipoproteins.
  • M. van Poppel will introduce students to biostatistics and the biology of angiogenesis.   
          

Know-how and infrastructure of the research group:

 

Dagmar Kratky is a biochemist and molecular biologist at the Institute of Molecular Biology and Biochemistry. Since 2006 she has been leading her own group, which currently comprises 1 senior scientist, 1 postdoctoral fellow, and 4 PhD students. Two technicians with permanent positions are financed by the MUG. Equipment and methodologies are available for gene cloning, DNA sequencing, real-time PCR analysis, heterologous expression of genes as well as gene silencing techniques and adenoviral infections, and an FPLC system for lipoprotein analysis. The local infrastructure includes cell culture facilities, an isotope laboratory, fluorescent and deconvolution microscopes, GC and HPLC systems for lipid analysis, a proteomics platform, and an XF24 Extracellular Flux Analyzer (Seahorse) for simultaneous measurements of oxygen consumption and extracellular acidification rates. Our animal facility houses more than 25 different mouse models.

Scientific concepts and techniques that students will learn in this laboratory:

 

In D. Kratky’s laboratory, DP-iDP students will get insights into whole body lipid and energy metabolism and the consequences of lipid and energy overload in disease. In addition, they will get background knowledge on biochemistry and cell biology of lipid droplet formation. DP-iDP students will be trained in radioactive and non-radioactive labeling of lipids and lipoproteins. Tracer experiments will include uptake studies of fatty acids and glucose. Students will learn RNA and DNA methodologies including isolation of RNA from tissues and cells, determine mRNA expression by RT and real-time PCR, isolate full-length cDNAs, clone cDNAs into protein expression vectors, transfect mammalian cells with recombinant constructs and silence specific genes with siRNA techniques. Moreover, selected collegiates will perform hydrolase activity assays, lipid uptake and efflux experiments, determine lipid parameters in plasma, cells and tissues, examine lipoprotein profiles, and analyze mRNA and protein expression. Students under D. Kratky’s supervision will be trained in animal handling and breeding, tissue and cell isolation, dietary studies, injections, blood sampling, and perfusions.

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