Surface glycans contribute to differences between seminal prostasomes from normozoospermic and oligozoospermic men

Urinary exosomes: Potential diagnostic markers and application in bladder cancer

Background

The exosome is a critical component of the intercellular communication., playing a vital role in regulating cell function. These small vesicles contain proteins, mRNAs, miRNAs, and lncRNAs, surrounded by lipid bilayer substances. Most cells in the human body can produce exosomes, released into various body fluids such as urine, blood, and cerebrospinal fluid. Bladder cancer is the most common tumor in the urinary system, with high recurrence and metastasis rates. Early diagnosis and treatment are crucial for improving patient outcomes.

Methods

This study employed the PubMed search engine to retrieve publicly accessible data pertaining to urinary exosomes.

Results

We summarize the origins and intricate biological characteristics of urinary exosomes, the introduction of research methodologies used in basic experiments to isolate and analyze these exosomes, the discussion of their applications and progress in the diagnosis and treatment of bladder cancer, and the exploration of the current limitations associated with using urinary exosomes as molecular biomarkers for diagnosing bladder cancer.

Conclusion

Exosomes isolated from urine may be used as molecular biomarkers for early detection of bladder cancer.

Extracellular vesicles and glycans: new avenue for biomarker research

The investigation of biomarkers is constantly evolving. New molecules and molecular assemblies, such as soluble and particulate complexes, emerged as biomarkers from basic research and investigation of different proteomes, genomes, and glycomes. Extracellular vesicles (EVs), and glycans, complex carbohydrates are ubiquitous in nature. The composition and structure of both reflect physiological state of paternal cells and are strikingly changed in diseases. The EV-associated glycans, alone or in combination with soluble glycans in related biological fluids, used as analytes, aim to capture full complex biomarker picture, enabling its use in different clinical settings. Bringing together EVs and glycans can help to extract meaningful data from their extreme and distinct heterogeneities for use in the real-time diagnostics. The glycans on the surface of EVs could mark their subpopulations and establish the glycosignature, the solubilisation signature and molecular patterns. They all contribute to a new way of looking at and looking for composite biomarkers.

Lectins as potential tools for cancer biomarker discovery from extracellular vesicles

Extracellular vesicles (EVs) have considerable potential as diagnostic, prognostic, and therapeutic agents, in large part because molecular patterns on the EV surface betray the cell of origin and may also be used to "target" EVs to specific cells. Cancer is associated with alterations to cellular and EV glycosylation patterns, and the surface of EVs is enriched with glycan moieties. Glycoconjugates of EVs play versatile roles in cancer including modulating immune response, affecting tumor cell behavior and site of metastasis and as such, paving the way for the development of innovative diagnostic tools and novel therapies. Entities that recognize specific glycans, such as lectins, may thus be powerful tools to discover and detect novel cancer biomarkers. Indeed, the past decade has seen a constant increase in the number of published articles on lectin-based strategies for the detection of EV glycans. This review explores the roles of EV glycosylation in cancer and cancer-related applications. Furthermore, this review summarizes the potential of lectins and lectin-based methods for screening, targeting, separation, and possible identification of improved biomarkers from the surface of EVs.

Development of tandem cation exchange chromatography for high purity extracellular vesicle isolation: The effect of ligand steric availability

Purification of extracellular vesicles for research and therapeutic applications requires updated methodology to address the limitations of traditional ultracentrifugation and other size-based separation techniques. Their downfalls include induced extracellular vesicle aggregation, low yields, poor scalability and one-dimensionality of the separation process, as the size or sedimentation speed of extracellular vesicles is often the only selection criterion. Ion exchange chromatography is a promising alternative or supplementary method candidate, as it offers a different approach for extracellular vesicle separation, which is surface charge. For now, mostly anion exchange chromatography has been evaluated for extracellular vesicle purification, as it successfully relies on the strongly negative surface charge of extracellular vesicles. However, as extracellular vesicles are very complex in their structure, also cation exchange chromatography could be applicable, due to individual cationic domains on the extracellular vesicle surface. Here, we compare anion exchange chromatography to different types of cation exchange chromatography for the purification of platelet extracellular vesicle samples also containing plasma-derived impurities. We found that the choice of resin structure used for cation exchange chromatography is critical for binding platelet extracellular vesicles, as a conventional-type cation exchanger was found to only capture and elute less than 20% of extracellular vesicles. With the tentacle-type resin, it was possible to obtain comparable platelet extracellular vesicle yields (over 90%) with cation exchange chromatography compared to anion exchange chromatography, as well as superior purity, especially when it was combined to conventional cation exchange resin.

Microfluidics facilitating the use of small extracellular vesicles in innovative approaches to male infertility

Sperm are transcriptionally and translationally quiescent and, therefore, rely on the seminal plasma microenvironment for function, survival and fertilization of the oocyte in the oviduct. The male reproductive system influences sperm function via the binding and fusion of secreted epididymal (epididymosomes) and prostatic (prostasomes) small extracellular vesicles (S-EVs) that facilitate the transfer of proteins, lipids and nucleic acids to sperm. Seminal plasma S-EVs have important roles in sperm maturation, immune and oxidative stress protection, capacitation, fertilization and endometrial implantation and receptivity. Supplementing asthenozoospermic samples with normospermic-derived S-EVs can improve sperm motility and S-EV microRNAs can be used to predict non-obstructive azoospermia. Thus, S-EV influence on sperm physiology might have both therapeutic and diagnostic potential; however, the isolation of pure populations of S-EVs from bodily fluids with current conventional methods presents a substantial hurdle. Many conventional techniques lack accuracy, effectiveness, and practicality; yet microfluidic technology has the potential to simplify and improve S-EV isolation and detection.

Seminal Plasma Glycoproteins as Potential Ligands of Lectins Engaged in Immunity Regulation

Environmental pollution, chronic stress, and unhealthy lifestyle are factors that negatively affect reproductive potential. Currently, 15-20% of couples in industrialized countries face the problem of infertility. This growing health and social problem prompts researchers to explore the regulatory mechanisms that may be important for successful fertilization. In recent years, more attention has been paid to male infertility factors, including the impact of seminal plasma components on regulation of the female immune response to allogenic sperm, embryo and fetal antigens. Directing this response to the tolerogenic pathway is crucial to achieve a healthy pregnancy. According to the fetoembryonic defense hypothesis, the regulatory mechanism may be associated with the interaction of lectins and immunomodulatory glycoepitopes. Such interactions may involve lectins of dendritic cells and macrophages, recruited to the cervical region immediately after intercourse. Carbohydrate binding receptors include C type lectins, such as DC-SIGN and MGL, as well as galectins and siglecs among others. In this article we discuss the expression of the possible lectin ligands, highly fucosylated and high mannose structures, which may be recognized by DC-SIGN, glycans of varying degrees of sialylation, which may differ in their interaction with siglecs, as well as T and Tn antigens in O-glycans.

Glycoproteins Presenting Galactose and N-Acetylgalactosamine in Human Seminal Plasma as Potential Players Involved in Immune Modulation in the Fertilization Process

In light of recent research, there is increasing evidence showing that extracellular semen components have a significant impact on the immune reaction of the female partner, leading to the tolerogenic response enabling the embryo development and implantation as well as further progress of healthy pregnancy. Seminal plasma glycoproteins are rich in the unique immunomodulatory glycoepitopes that may serve as ligands for endogenous lectins that decorate the surface of immune cells. Such interaction may be involved in modulation of the maternal immune response. Among immunomodulatory glycans, Lewis type antigens have been of interest for at least two decades, while the importance of T/Tn antigens and related structures is still far from understanding. In the current work, we applied two plant lectins capable of distinguishing glycoepitopes with terminal GalNAc and Gal to identify glycoproteins that are their efficient carriers. By means of lectin blotting and lectin affinity chromatography followed by LC-MS, we identified lactotransferrin, prolactin inducible protein as well as fibronectin and semenogelins 1 and 2 as lectin-reactive. Net-O-glycosylation analysis results indicated that the latter three may actually carry T and/or Tn antigens, while in the case of prolactin inducible protein and lactotransferrin LacdiNAc and lactosamine glycoepitopes were more probable. STRING bioinformatics analysis linked the identified glycoproteins in the close network, indicating their involvement in immune (partially innate) processes. Overall, our research revealed potential seminal plasma ligands for endogenous Gal/GalNAc specific lectins with a possible role in modulation of maternal immune response during fertilization.

Assembly of tetraspanins, galectin-3, and distinct N-glycans defines the solubilization signature of seminal prostasomes from normozoospermic and oligozoospermic men

BACKGROUND

Prostasomes, extracellular vesicles (EVs) abundantly present in seminal plasma, express distinct tetraspanins (TS) and galectin-3 (gal-3), which are supposed to shape their surface by an assembly of different molecular complexes. In this study, detergent-sensitivity patterns of membrane-associated prostasomal proteins were determined aiming at the solubilization signature as an intrinsic multimolecular marker and a new parameter suitable as a reference for the comparison of EVs populations in health and disease.

METHODS

Prostasomes were disrupted by Triton X-100 and analyzed by gel filtration under conditions that maintained complete solubilization. Redistribution of TS (CD63, CD9, and CD81), gal-3, gamma-glutamyltransferase (GGT), and distinct N-glycans was monitored using solid-phase lectin-binding assays, transmission electron microscopy, electrophoresis, and lectin blot.

RESULTS

Comparative data on prostasomes under normal physiology and conditions of low sperm count revealed similarity regarding the redistribution of distinct N-glycans and GGT, all presumed to be mainly part of the vesicle coat. In contrast to this, a greater difference was found in the redistribution of integral membrane proteins, exemplified by TS and gal-3. Accordingly, they were grouped into two molecular patterns mainly consisting of overlapped CD9/gal-3/wheat germ agglutinin-reactive glycoproteins and CD63/GGT/concanavalin A-reactive glycoproteins.

CONCLUSIONS

Solubilization signature can be considered as an all-inclusive distinction factor regarding the surface properties of a particular vesicle since it reflects the status of the parent cell and the extracellular environment, both of which contribute to the composition of spatial membrane arrangements.

Membrane-associated gamma-glutamyl transferase and alkaline phosphatase in the context of concanavalin A- and wheat germ agglutinin-reactive glycans mark seminal prostasome populations from normozoospermic and oligozoospermic men

Background: Human seminal prostasomes are intrinsically heterogeneous extracellular vesicles (EVs) whose composition is, additionally, influenced by different physiological conditions. Aiming at the molecular properties of the prostasomal surface exemplified by glycan compositions as a possible distinction factor, we applied lectin-affinity chromatography (LAC) as a new tool for their separation. Since glycans, generally, exhibit various biological activities, introduction of glyco-parameters as reference could upgrade standardization of EVs isolated by different methods and intended for use in biomedicine.Methods: Preparations of seminal prostasomes from normozoospermic (sPro-N) and oligozoospermic (sPro-O) men were subjected to LAC on concanavalin A (Con A) and wheat germ agglutinin (WGA) columns. Prostasomes recovered in LAC-separated fractions were characterized according to the distribution of selected markers: gamma-glutamyl transferase (GGT), alkaline phosphatase (ALP), tetraspanin CD63, and total protein/glycoprotein composition.Results: Two CD63-immunoreactive populations exhibiting prostasome signature bands but differing in GGT activity and surface glycans were separated on the WGA column. Additional populations having distinct profiles of total glycoproteins and which can be tracked down by ALP activity were enriched on the Con A column. WGA-separated populations were similar in sPro-N and sPro-O, whereas Con A-separated ones were strikingly different.Conclusions: Membrane-associated gamma-glutamyl transferase and alkaline phosphatase in the context of Con A- and WGA-reactive glycans mark seminal prostasomes populations from normozoospermic and oligozoospermic men.