XI International Meeting on Paracoccidioidomycosis

XI International Meeting on Paracoccidioidomycosis

Resume:19-1

Oral / Poster

19-1

Comparative analysis of cell surface-associated lipids using Paracoccidioides brasiliensis Pb18 and Pb3 as model

Authors:

Larissa Valle Guilhen Longo (UNIFESP - Universidade Federal de Sao Paulo) ; Ernesto S Nakayasu (UTEP - University of Texas at El Paso) ; Felipe Gazos Lopes (UTEP - University of Texas at El Paso) ; Alisson Leonardo Matsuo (UNIFESP - Universidade Federal de Sao Paulo) ; Milene Carmes Vallejo (UNIFESP - Universidade Federal de Sao Paulo) ; Igor Correia Almeida (UTEP - University of Texas at El Paso) ; Rosana Puccia (UNIFESP - Universidade Federal de Sao Paulo)

Abstract

We compared the cell surface-associated lipids of the yeast phase from Paracoccidioides brasiliensis Pb3 and Pb18, which represent different phylogenetic groups and cause paracoccidioidomycosis in B10.A mice with distinct characteristics. The isolates were cultivated in Ham`s defined medium/glucose in the presence or absence of human plasma. Lipids from 100 mg of cell-free, extensively washed cell wall preparations were sequentially extracted with chloroform:methanol (2:1, v/v) and chloroform:methanol:water (1:2:0.8, v/v/v), and fractionated in a silica-gel 60 column in sterols, glycolipids, and phospholipids. Phospholipids and glycolipids were analyzed by ESI-LIT-MS/MS while sterols and fatty acids isolated from phospholipids were analyzed by GC-MS/MS. In both isolates, we found phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidic acid (PA), phosphatidylinositol (PI), phosphatidylserine (PS), and phosphatidylglycerol (PG). Nevertheless, a higher number of PA and PG species was found in Pb18. Fatty acid composition showed that both oleic acid (C18:1) and linoleic acid (C18:2) were prevalent in Pb18, but only C18:1 was prevalent in Pb3. In Pb18, plasma evoked an increase of C18:1 and C18:2, whereas in Pb3 there was a slight decrease of both fatty acids in the presence of plasma. Palmitic acid (C16:0) and stearic acid (C18:0) were also detected in both isolates, but in small amounts. A single abundant glycosphingolipid, Hex-h18:0/d19:2-Cer, and small amounts of Hex-h18:1/d19:2-Cer were detected in Pb3 and Pb18. The presence of plasma in the culture medium induced a remarkable increase of some sterols (e.g., campesterol, ergostadienol, and ergosterol), especially in Pb3. The increase of ergostadienol in the presence of plasma was almost 12-fold in Pb3, versus 2.5-fold in Pb18. When cultivated in the presence of plasma, Pb3 also incorporated to the cell wall 2.3-fold more cholesterol than Pb18. Similar lipidomic data were found when extracellular vesicles from both isolates were analyzed, which suggests that at least part of the cell wall-associated lipids derives from vesicles crossing the cell wall. Our results might help to understand the distinct aspects of virulence showed by Pb3 and Pb18. Support: FAPESP, CNPq, NIH (grants # 5G12RR008124-16A1 and 5G12RR008124-16A1S1)

Keyword: cell wall, lipids, Paracoccidioides brasiliensis, phospholipids, sterols

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