Isolation of Exosomes and Microvesicles from Cell Culture Systems to Study Prion Transmission.

Extracellular vesicles (EVs) are composed of microvesicles and exosomes. Exosomes are small membrane vesicles (40-120 nm sized) of endosomal origin released in the extracellular medium from cells when multivesicular bodies fuse with the plasma membrane, whereas microvesicles (i.e.

Efficient inhibition of infectious prions multiplication and release by targeting the exosomal pathway.

Exosomes are secreted membrane vesicles of endosomal origin present in biological fluids. Exosomes may serve as shuttles for amyloidogenic proteins, notably infectious prions, and may participate in their spreading in vivo. To explore the significance of the exosome pathway on prion infectivity and release, we investigated the role of the endosomal sorting complex required for transport (ESCRT) machinery and the need for ceramide, both involved in exosome biogenesis.

Prion strains are differentially released through the exosomal pathway.

Cell-to-cell transfer of prions is a crucial step in the spreading of prion infection through infected tissue. At the cellular level, several distinct pathways including direct cell-cell contacts and release of various types of infectious extracellular vesicles have been described that may potentially lead to infection of naïve cells. The relative contribution of these pathways and whether they may vary depending on the prion strain and/or on the infected cell type are not yet known.

Two dimensional gel electrophoresis analysis of mesenchymal stem cells.

Proteomic analysis is a powerful tool to follow physiological modifications and phenotypes of mesenchymal stem cells (MSC). This approach generates informative data on expression and post-translational modifications of proteins which are of interest to assess the true potential of MSC in regenerative medicine. No matter the technologies used, proteomic analysis is always a challenge as the proteome is extremely diverse (in terms of constituents and concentrations), is changing with time, and is highly sensitive to pre-analytical conditions.

Depletion of one, six, twelve or twenty major blood proteins before proteomic analysis: the more the better?

Depletion of major blood proteins is one of the most promising approaches to access low abundant biomarkers using proteomics. Immunocapture columns often used for this purpose exist in different formats depending on the number of major proteins removed. In this article, we compared the relative interest of depleting either one (albumin), six (albumin, IgG, IgA, transferrin, alpha1-antitrypsin, and haptoglobin), twelve (the previous six and apo A-I and -II, orosomucoid, alpha2-macroglobulin, fibrinogen, IgM) or twenty blood proteins (the previous twelve and IgD, ceruloplasmin, apo B, complement C1q, C3, C4, plasminogen, and prealbumin).

Autoantibody profiling on high-density protein microarrays for biomarker discovery in the cerebrospinal fluid.

Detection of autoantibodies, which are involved in tissue injury and/or the reporters from the immune system of various pathologic events, has an important potential for diagnosis, prognosis, disease staging and treatment selection. This explains the interest for new proteomics technologies, such as the high-density protein microarray used here, that allow a high-throughput, multiplexed and sensitive detection of specific autoantibodies. So far, most of the research has been performed on blood.

Interest of major serum protein removal for Surface-Enhanced Laser Desorption/Ionization - Time Of Flight (SELDI-TOF) proteomic blood profiling.

Background: Surface-Enhanced Laser Desorption/Ionization - Time Of Flight (SELDI-TOF) has been proposed as new approach for blood biomarker discovery. However, results obtained so far have been often disappointing as this technique still has difficulties to detect low-abundant plasma and serum proteins.

Results: We used a serum depletion scheme using chicken antibodies against various abundant proteins to realized a pre-fractionation of serum prior to SELDI-TOF profiling.