Time filter

Source Type

Helsinki, Finland

Espino E.,University of Helsinki | Koskenniemi K.,University of Helsinki | Koskenniemi K.,Ductor Corporation | Mato-Rodriguez L.,University of Helsinki | And 9 more authors.
Journal of Proteome Research | Year: 2015

The present study reports the identification and comparison of all expressed cell-surface exposed proteins from the well-known probiotic L. rhamnosus GG and a related dairy strain, Lc705. To obtain this information, the cell-surface bound proteins were released from intact cells by trypsin shaving under hypertonic conditions with and without DTT. Liquid chromatography tandem mass spectrometry (LC-MS/MS) analyses of the purified peptides identified a total of 102 and 198 individual proteins from GG and Lc705, respectively. Comparison of both data sets suggested that the Msp-type antigens (Msp1, Msp2) and the serine protease HtrA were uniquely exposed at the cell surface of GG, whereas the Lc705-specific proteins included lactocepin and a wider range of different moonlighting proteins. ImmunoEM analyses with the GG and Lc705 antibodies suggested that the whole-cell immunization yielded antibodies toward surface-bound proteins and proteins that were secreted or released from the cell-surface. One of the detected antigens was a pilus-like structure on the surface of GG cells, which was not detected with Lc705 antibodies. Further 2-DE immunoblotting analysis of GG proteins with both L. rhamnosus antisera revealed that majority of the detected antigens were moonlighting proteins with potential roles in adhesion, pathogen exclusion or immune stimulation. The present study provides the first catalog of surface-exposed proteins from lactobacilli and highlights the importance of the specifically exposed moonlighting proteins for adaptation and probiotic functions of L. rhamnosus. © 2015 American Chemical Society. Source

Rahkila J.,Abo Akademi University | Ekholm F.S.,Abo Akademi University | Ekholm F.S.,Glykos Finland Ltd. | Panchadhayee R.,Abo Akademi University | And 4 more authors.
Carbohydrate Research | Year: 2014

Phosphorylated β-(1→2)-oligomannosides are found on the cell surface of several Candida species, including Candida albicans (an opportunistic pathogen). These molecules are believed to take part in the invasion process of fungal infections, which in the case of C. albicans can lead to severe bloodstream infections and death, and can therefore be considered important from a biological standpoint. Understanding the mechanism of their action requires access to the corresponding oligosaccharide model compounds in pure form. In the present work, synthesis of the model core structures involved in the invasion process of C. albicans, consisting of phosphorylated β-(1→2)-linked mannotriose and tetraose, is reported. In order to elucidate the nature of these molecules in more detail, an extensive NMR-spectroscopic study encompassing complete spectral characterization, conformational analysis and molecular modelling was performed. The obtained results were also compared to similar chemical entities devoid of the charged phosphate group. © 2013 Elsevier Ltd. All rights reserved. Source

Nystedt J.,Finnish Red Cross Blood Service | Anderson H.,Finnish Red Cross Blood Service | Tikkanen J.,Finnish Red Cross Blood Service | Pietila M.,University of Oulu | And 12 more authors.
Stem Cells | Year: 2013

The promising clinical effects of mesenchymal stromal/ stem cells (MSCs) rely especially on paracrine and nonimmunogenic mechanisms. Delivery routes are essential for the efficacy of cell therapy and systemic delivery by infusion is the obvious goal for many forms of MSC therapy. Lung adhesion of MSCs might, however, be a major obstacle yet to overcome. Current knowledge does not allow us to make sound conclusions whether MSC lung entrapment is harmful or beneficial, and thus we wanted to explore MSC lung adhesion in greater detail. We found a striking difference in the lung clearance rate of systemically infused MSCs derived from two different clinical sources, namely bone marrow (BM-MSCs) and umbilical cord blood (UCB-MSCs). The BM-MSCs and UCB-MSCs used in this study differed in cell size, but our results also indicated other mechanisms behind the lung adherence. A detailed analysis of the cell surface profiles revealed differences in the expression of relevant adhesion molecules. The UCB-MSCs had higher expression levels of a4 integrin (CD49d, VLA-4), a6 integrin (CD49f, VLA-6), and the hepatocyte growth factor receptor (c-Met) and a higher general fucosylation level. Strikingly, the level of CD49d and CD49f expression could be functionally linked with the lung clearance rate. Additionally, we saw a possible link between MSC lung adherence and higher fibronectin expression and we show that the expression of fibronectin increases with MSC culture confluence. Future studies should aim at developing methods of transiently modifying the cell surface structures in order to improve the delivery of therapeutic cells. © 2012 AlphaMed Press. Source

Kandiba L.,Ben - Gurion University of the Negev | Aitio O.,University of Helsinki | Aitio O.,Glykos Finland Ltd. | Helin J.,Glykos Finland Ltd. | And 5 more authors.
Molecular Microbiology | Year: 2012

VP4, the major structural protein of the haloarchaeal pleomorphic virus, HRPV-1, is glycosylated. To define the glycan structure attached to this protein, oligosaccharides released by β-elimination were analysed by mass spectrometry and nuclear magnetic resonance spectroscopy. Such analyses showed that the major VP4-derived glycan is a pentasaccharide comprising glucose, glucuronic acid, mannose, sulphated glucuronic acid and a terminal 5-N-formyl-legionaminic acid residue. This is the first observation of legionaminic acid, a sialic acid-like sugar, in an archaeal-derived glycan structure. The importance of this residue for viral infection was demonstrated upon incubation with N-acetylneuraminic acid, a similar monosaccharide. Such treatment reduced progeny virus production by half 4h post infection. LC-ESI/MS analysis confirmed the presence of pentasaccharide precursors on two different VP4-derived peptides bearing the N-glycosylation signal, NTT. The same sites modified by the native host, Halorubrum sp. strain PV6, were also recognized by the Haloferax volcanii N-glycosylation apparatus, as determined by LC-ESI/MS of heterologously expressed VP4. Here, however, the N-linked pentasaccharide was the same as shown to decorate the S-layer glycoprotein in this species. Hence, N-glycosylation of the haloarchaeal viral protein, VP4, is host-specific. These results thus present additional examples of archaeal N-glycosylation diversity and show the ability of Archaea to modify heterologously expressed proteins. © 2012 Blackwell Publishing Ltd. Source

Kaprio T.,University of Helsinki | Satomaa T.,Glykos Finland Ltd. | Heiskanen A.,Glykos Finland Ltd. | Hokke C.H.,Leiden University | And 6 more authors.
Molecular and Cellular Proteomics | Year: 2015

All human cells are covered by glycans, the carbohydrate units of glycoproteins, glycolipids, and proteoglycans. Most glycans are localized to cell surfaces and participate in events essential for cell viability and function. Glycosylation evolves during carcinogenesis, and therefore carcinoma- related glycan structures are potential cancer biomarkers. Colorectal cancer is one of the world's three most common cancers, and its incidence is rising. Novel biomarkers are essential to identify patients for targeted and individualized therapy. We compared the N-glycan profiles of five rectal adenomas and 18 rectal carcinomas of different stages by matrix-assisted laser desorption ionization time-of-flight mass spectrometry. Paraffin-embedded tumor samples were deparaffinized, and glycans were enzymatically released and purified. We found differences in glycosylation between adenomas and carcinomas: monoantennary, sialylated, pauci-mannose, and small high-mannose N-glycan structures were more common in carcinomas than in adenomas. We also found differences between stage I-II and stage III carcinomas. Based on these findings, we selected two glycan structures: pauci-mannose and sialyl Lewis a, for immunohistochemical analysis of their tissue expression in 220 colorectal cancer patients. In colorectal cancer, poor prognosis correlated with elevated expression of sialyl Lewis a, and in advanced colorectal cancer, poor prognosis correlated with elevated expression of pauci-mannose. In conclusion, by mass spectrometry we found several carcinoma related glycans, and we demonstrate a method of transforming these results into immunohistochemistry, a readily applicable method to study biomarker expression in patient samples. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc. Source

Discover hidden collaborations