Different biomarkers are investigated to detect the causes of severe complications in preterm infants. Extracellular vesicles (EVs) are recognized as an important part of cell-to-cell communication, and their increased levels were reported in numerous pathological states. We aimed to increase our knowledge about the incidence of platelet and endothelial EVs in cord blood of preterm newborns using conventional flow cytometry. The presence of platelet (CD36+CD41+), activated platelet (CD41+CD62+), and endothelial (CD31+CD105+) EVs was analyzed. Immune electron microscopy was used to confirm the presence of EVs and the specificity of their labeling. The size of detected extracellular vesicles was in the range 400-2000 nm. The differences in the counts of EVs between the preterm and control group were not significant and no correlation of EVs count with gestation age was recorded. Cord blood plasma samples with free hemoglobin level > 1 mg/mL had more than threefold higher counts of CD36+CD41+ and CD41+CD62+ EVs (p < 0.001), while the count of CD31+CD105+ EVs was only moderately increased (p < 0.05). Further studies utilizing cytometers with improved sensitivity are needed to confirm that the analysis of large platelet and endothelial EVs mirrors the quantitative situation of their whole plasma assemblage.

• Keywords
• cord blood, extracellular vesicles, flow cytometry, immune electron microscopy,
• Publication type
• Journal Article MeSH

Transmissive spongiform encephalopathies (TSE) are neurodegenerative diseases characterized by depositions of abnormally folded prion protein (PrP(TSE)) in brain. PrP(TSE) is at present the only specific biochemical marker of human and animal TSE. As deposits of PrP(TSE) remain in the body for long periods, there is substantial chance of them being nonenzymatically modified by glycation. The detection of glycated PrP(TSE) may have potential to serve as a diagnostic marker. Monoclonal antibodies specific for carboxymethyl lysine/arginine-modified prion protein were prepared. Recombinant human prion protein (rhPrP) was bacterially expressed and purified by affinity chromatography. rhPrP was modified by glyoxylic acid that introduces carboxymethyl groups on lysine and arginine residues present within the molecule of the protein. Modified rhPrP (rhPrP-CML) was used for immunization of 6 mice, and 960 hybridoma cells were prepared. Screening of cell supernatants resulted in the selection of four promising clones. One of them (EM-31) strongly reacts with human and mouse recombinant PrP-CML, and three other clones react also with CML in vitro modified human and mouse brain PrP. Besides possible implication in TSE diagnostics, the antibodies may serve as tolls to advance our knowledge regarding the role of glycation in the prion pathophysiology.

• MeSH
• Arginine analogs & derivatives   chemistry   metabolism   MeSH
• Glycosylation MeSH
• Hybridomas immunology   metabolism   MeSH
• Humans MeSH
• Lysine analogs & derivatives   chemistry   metabolism   MeSH
• Antibodies, Monoclonal * immunology   metabolism   MeSH
• Brain immunology   metabolism   MeSH
• Mice, Knockout MeSH
• Mice, Transgenic MeSH
• Mice MeSH
• Peptides chemistry   metabolism   MeSH
• Prion Diseases diagnosis   immunology   metabolism   MeSH
• Prions * chemistry   metabolism   MeSH
• Recombinant Proteins chemistry   metabolism   MeSH
• Animals MeSH
• Check Tag
• Humans MeSH
• Mice MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Arginine MeSH
• Lysine MeSH
• Antibodies, Monoclonal * MeSH
• N(6)-carboxymethyllysine MeSH Browser
• Peptides MeSH
• Prions * MeSH
• Recombinant Proteins MeSH

Prion diseases have been observed to deregulate the transcription of erythroid genes, and prion protein knockout mice have demonstrated a diminished response to experimental anemia. To investigate the role of the cellular prion protein (PrP(C)) in erythropoiesis, we studied the protein's expression on mouse erythroid precursors in vivo and utilized an in vitro model of the erythroid differentiation of murine erythroleukemia cells (MEL) to evaluate the effect of silencing PrP(C) through RNA interference.The expression of PrP(C) and selected differentiation markers was analyzed by quantitative multicolor flow cytometry, western blot analysis and quantitative RT-PCR. The silencing of PrP(C) expression in MEL cells was achieved by expression of shRNAmir from an integrated retroviral vector genome. The initial upregulation of PrP(C) expression in differentiating erythroid precursors was detected both in vivo and in vitro, suggesting PrP(C)'s importance to the early stages of differentiation. The upregulation was highest on early erythroblasts (16200±3700 PrP(C) / cell) and was followed by the gradual decrease of PrP(C) level with the precursor's maturation reaching 470±230 PrP(C) / cell on most mature CD71(-)Ter119(+) small precursors. Interestingly, the downregulation of PrP(C) protein with maturation of MEL cells was not accompanied by the decrease of PrP mRNA. The stable expression of anti-Prnp shRNAmir in MEL cells led to the efficient (>80%) silencing of PrP(C) levels. Cell growth, viability, hemoglobin production and the transcription of selected differentiation markers were not affected by the downregulation of PrP(C).In conclusion, the regulation of PrP(C) expression in differentiating MEL cells mimics the pattern detected on mouse erythroid precursors in vivo. Decrease of PrP(C) protein expression during MEL cell maturation is not regulated on transcriptional level. The efficient silencing of PrP(C) levels, despite not affecting MEL cell differentiation, enables created MEL lines to be used for studies of PrP(C) cellular function.

• MeSH
• Leukemia, Erythroblastic, Acute genetics   pathology   MeSH
• Cell Differentiation genetics   MeSH
• Bone Marrow Cells cytology   MeSH
• Down-Regulation MeSH
• Erythroid Precursor Cells cytology   metabolism   MeSH
• Genetic Vectors genetics   MeSH
• Hemoglobins biosynthesis   MeSH
• RNA, Small Interfering genetics   MeSH
• RNA, Messenger genetics   metabolism   MeSH
• Mice MeSH
• Cell Line, Tumor MeSH
• Prions genetics   MeSH
• Gene Expression Regulation, Neoplastic * MeSH
• Retroviridae genetics   MeSH
• RNA Interference MeSH
• Spleen cytology   MeSH
• Animals MeSH
• Check Tag
• Mice MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Hemoglobins MeSH
• RNA, Small Interfering MeSH
• RNA, Messenger MeSH
• Prions MeSH