@article{CullLimaPradoGodinhoFernandesRodriguesetal.2014, author = {Cull, Benjamin and Lima Prado Godinho, Joseane and Fernandes Rodrigues, Juliany Cola and Frank, Benjamin and Schurigt, Uta and Williams, Roderick AM and Coombs, Graham H and Mottram, Jeremy C}, title = {Glycosome turnover in Leishmania major is mediated by autophagy}, series = {Autophagy}, volume = {10}, journal = {Autophagy}, number = {12}, doi = {10.4161/auto.36438}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-150277}, pages = {2143-2157}, year = {2014}, abstract = {Autophagy is a central process behind the cellular remodeling that occurs during differentiation of Leishmania, yet the cargo of the protozoan parasite's autophagosome is unknown. We have identified glycosomes, peroxisome-like organelles that uniquely compartmentalize glycolytic and other metabolic enzymes in Leishmania and other kinetoplastid parasitic protozoa, as autophagosome cargo. It has been proposed that the number of glycosomes and their content change during the Leishmania life cycle as a key adaptation to the different environments encountered. Quantification of RFP-SQL-labeled glycosomes showed that promastigotes of L. major possess ~20 glycosomes per cell, whereas amastigotes contain ~10. Glycosome numbers were significantly greater in promastigotes and amastigotes of autophagy-defective L. major Δatg5 mutants, implicating autophagy in glycosome homeostasis and providing a partial explanation for the previously observed growth and virulence defects of these mutants. Use of GFP-ATG8 to label autophagosomes showed glycosomes to be cargo in ~15\% of them; glycosome-containing autophagosomes were trafficked to the lysosome for degradation. The number of autophagosomes increased 10-fold during differentiation, yet the percentage of glycosome-containing autophagosomes remained constant. This indicates that increased turnover of glycosomes was due to an overall increase in autophagy, rather than an upregulation of autophagosomes containing this cargo. Mitophagy of the single mitochondrion was not observed in L. major during normal growth or differentiation; however, mitochondrial remnants resulting from stress-induced fragmentation colocalized with autophagosomes and lysosomes, indicating that autophagy is used to recycle these damaged organelles. These data show that autophagy in Leishmania has a central role not only in maintaining cellular homeostasis and recycling damaged organelles but crucially in the adaptation to environmental change through the turnover of glycosomes.}, language = {en} } @article{GlaserSchultheisHazraetal.2014, author = {Glaser, Jan and Schultheis, Martina and Hazra, Sudipta and Hazra, Banazri and Moll, Heidrun and Schurigt, Uta and Holzgrabe, Ulrike}, title = {Antileishmanial Lead Structures from Nature: Analysis of Structure-Activity Relationships of a Compound Library Derived from Caffeic Acid Bornyl Ester}, doi = {10.3390/molecules19021394}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-112835}, year = {2014}, abstract = {Bioassay-guided fractionation of a chloroform extract of Valeriana wallichii (V. wallichii) rhizomes lead to the isolation and identification of caffeic acid bornyl ester (1) as the active component against Leishmania major (L. major) promastigotes (IC50 = 48.8 µM). To investigate the structure-activity relationship (SAR), a library of compounds based on 1 was synthesized and tested in vitro against L. major and L. donovani promastigotes, and L. major amastigotes. Cytotoxicity was determined using a murine J774.1 cell line and bone marrow derived macrophages (BMDM). Some compounds showed antileishmanial activity in the concentration range of pentamidine and miltefosine which are the standard drugs in use. In the L. major amastigote assay compounds 15, 19 and 20 showed good activity with relatively low cytotoxicity against BMDM, resulting in acceptable selectivity indices. Molecules with adjacent phenolic hydroxyl groups exhibited elevated cytotoxicity against murine cell lines J774.1 and BMDM. The Michael system seems not to be essential for antileishmanial activity. Based on the results compound 27 can be regarded as new lead structure for further structure optimization}, language = {en} }