Biological function of Extracellular Vesicles (EVs): a review of the field

Proteomics of plasma-derived extracellular vesicles reveals S100A8 as a novel biomarker for Alzheimer's disease: A preliminary study

Extracellular vesicles (EVs) act as mediators for intercellular transfer of Aβ and tau proteins, promoting the propagation of these pathological misfolded proteins throughout the brain in Alzheimer's disease (AD). Levels of blood exosomal Aβ42, total Tau (t-Tau) and phosphorylated Tau (p-Tau) had a high correlation with their concentrations in cerebrospinal fluid (CSF), demonstrating that exosomal biomarkers have equal contribution as those in CSF for the diagnosis of AD. We aimed to comprehensively characterize the proteome of plasma-derived EVs to identify differentially expressed proteins (DEPs) and pathways in AD. Tandem mass tag (TMT) labeled quantitative proteomics was applied to analyze plasma-derived EV proteins in 9 AD patients and 9 healthy controls. 335 proteins were quantified, and 12 DEPs were identified including seven upregulated proteins and five down-regulated proteins. Oligomerized Aβ1-42 induced SH-SY5Y cell damage model was built to mimic the pathological changes of AD, and small interfering RNA (siRNA) against S100A8 was used to knock down S100A8 expression. Results displayed S100A8 was down regulated in plasma-derived EVs from AD patients, while enriched in EVs derived from Aβ1-42-induced SH-SY5Y cells. Furthermore, Aβ1-42-induced SH-SY5Y cells treated with S100A8 siRNA showed decreased Aβ levels in cell lysate and EVs, especially in EVs. SIGNIFICANCE: The investigation aimed to comprehensively characterize the proteome of plasma-derived EVs to identify DEPs and potential biomarker of AD. S100A8 was found down regulated in plasma-derived EVs from AD patients using TMT labeled quantitative proteomics. The diagnostic value of S100A8 was also confirmed using receiver operating characteristic curve (ROC) analysis. Furthermore, Aβ1-42-induced SH-SY5Y cells treated with S100A8 siRNA showed decreased Aβ levels in cell lysate and EVs, especially in EVs. The preliminary findings suggest that suppression of S100A8 expression inhibits Aβ aggregation both in cell lysate and EVs from Aβ1-42-induced SH-SY5Y cells, and S100A8 more likely regulates Aβ aggregation via EVs. Therefore, plasma-derived EV S100A8 might be a potential biomarker of AD. Manipulation of S100A8 expression may be a novel therapeutic strategy in the treatment of AD.

Secretome analysis using Affinity Proteomics and Immunoassays: a focus on Tumor Biology

The study of the cellular secretome using proteomic techniques continues to capture the attention of the research community across a broad range of topics in biomedical research. Due to their untargeted nature, independence from the model system employed, historically superior depth of analysis, as well as comparative affordability, mass spectrometry-based approaches traditionally dominate such analyses. More recently, however, affinity-based proteomic assays have massively gained in analytical depth, which together with their high sensitivity, dynamic range coverage as well as high throughput capabilities render them exquisitely suited to secretome analysis. In this review, we revisit the analytical challenges implied by secretomics and provide an overview of affinity-based proteomic platforms currently available for such analyses, using the study of the tumor secretome as an example for basic and translational research.

Cell Therapies for Acute Radiation Syndrome

The risks of severe ionizing radiation exposure are increasing due to the involvement of nuclear powers in combat operations, the increasing use of nuclear power, and the existence of terrorist threats. Exposure to a whole-body radiation dose above about 0.7 Gy results in H-ARS (hematopoietic acute radiation syndrome), which is characterized by damage to the hematopoietic system; higher doses result in further damage to the gastrointestinal and nervous systems. Only a few medical countermeasures for ARS are currently available and approved for use, although others are in development. Cell therapies (cells or products produced by cells) are complex therapeutics that show promise for the treatment of radiation injury and have been shown to reduce mortality and morbidity in animal models. Since clinical trials for ARS cannot be ethically conducted, animal testing is extremely important. Here, we describe cell therapies that have been tested in animal models. Both cells and cell products appear to promote survival and lessen tissue damage after whole-body irradiation, although the mechanisms are not clear. Because radiation exposure often occurs in conjunction with other traumatic injuries, animal models of combined injury involving radiation and future countermeasure testing for these complex medical problems are also discussed.

Roles of Myokines and Muscle-Derived Extracellular Vesicles in Musculoskeletal Deterioration under Disuse Conditions

Prolonged inactivity and disuse conditions, such as those experienced during spaceflight and prolonged bedrest, are frequently accompanied by detrimental effects on the motor system, including skeletal muscle atrophy and bone loss, which greatly increase the risk of osteoporosis and fractures. Moreover, the decrease in glucose and lipid utilization in skeletal muscles, a consequence of muscle atrophy, also contributes to the development of metabolic syndrome. Clarifying the mechanisms involved in disuse-induced musculoskeletal deterioration is important, providing therapeutic targets and a scientific foundation for the treatment of musculoskeletal disorders under disuse conditions. Skeletal muscle, as a powerful endocrine organ, participates in the regulation of physiological and biochemical functions of local or distal tissues and organs, including itself, in endocrine, autocrine, or paracrine manners. As a motor organ adjacent to muscle, bone tissue exhibits a relative lag in degenerative changes compared to skeletal muscle under disuse conditions. Based on this phenomenon, roles and mechanisms involved in the communication between skeletal muscle and bone, especially from muscle to bone, under disuse conditions have attracted widespread attention. In this review, we summarize the roles and regulatory mechanisms of muscle-derived myokines and extracellular vesicles (EVs) in the occurrence of muscle atrophy and bone loss under disuse conditions, as well as discuss future perspectives based on existing research.

Relevance of multilamellar and multicompartmental vesicles in biological fluids: understanding the significance of proportional variations and disease correlation

Extracellular vesicles (EVs) have garnered significant interest in the field of biomedical science due to their potential applications in therapy and diagnosis. These vesicles participate in cell-to-cell communication and carry a diverse range of bioactive cargo molecules, such as nucleic acids, proteins, and lipids. These cargoes play essential roles in various signaling pathways, including paracrine and endocrine signaling. However, our understanding of the morphological and structural features of EVs is still limited. EVs could be unilamellar or multilamellar or even multicompartmental structures. The relative proportions of these EV subtypes in biological fluids have been associated with various human diseases; however, the mechanism remains unclear. Cryo-electron microscopy (cryo-EM) holds great promise in the field of EV characterization due to high resolution properties. Cryo-EM circumvents artifacts caused by fixation or dehydration, allows for the preservation of native conformation, and eliminates the necessity for staining procedures. In this review, we summarize the role of EVs biogenesis and pathways that might have role on their structure, and the role of cryo-EM in characterization of EVs morphology in different biological samples and integrate new knowledge of the alterations of membranous structures of EVs which could be used as biomarkers to human diseases.