Extracellular vesicles (EVs) are heterogeneous lipid containers with a complex molecular cargo comprising several populations with unique roles in biological processes. These vesicles are closely associated with specific physiological features, which makes them invaluable in the detection and monitoring of various diseases. EVs play a key role in pathophysiological processes by actively triggering genetic or metabolic responses. However, the heterogeneity of their structure and composition hinders their application in medical diagnosis and therapies. This diversity makes it difficult to establish their exact physiological roles, and the functions and composition of different EV (sub)populations. Ensemble averaging approaches currently employed for EV characterization, such as western blotting or ‘omics’ technologies, tend to obscure rather than reveal these heterogeneities. Recent developments in single-vesicle analysis have made it possible to overcome these limitations and have facilitated the development of practical clinical applications. In this review, we discuss the benefits and challenges inherent to the current methods for the analysis of single vesicles and review the contribution of these approaches to the understanding of EV biology. We describe the contributions of these recent technological advances to the characterization and phenotyping of EVs, examination of the role of EVs in cell-to-cell communication pathways and the identification and validation of EVs as disease biomarkers. Finally, we discuss the potential of innovative single-vesicle imaging and analysis methodologies using microfluidic devices, which promise to deliver rapid and effective basic and practical applications for minimally invasive prognosis systems. Understanding the heterogeneity of extracellular vesicles is crucial for unraveling their functions. This review describes the benefits, challenges and contributions of the state-of-the art methods used in single-vesicle analysis.

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Using single-vesicle technologies to unravel the heterogeneity of extracellular vesicles.

The microflora and pH of gastric contents were determined in breast-fed and in bottle-fed normal infants, in well nourished infants with acute diarrhoea and in infants with chronic diarrhoea and protein-calorie malnutrition. The last group of infants was reevaluated after recovery from diarrhoea and protein-calorie malnutrition. A bactericidal pH effect below 2-5 was observed. Bottle-fed controls had low pH values and low bacterial concentrations, whereas infants with chronic diarrhoea and protein-calorie malnutrition had high pH values and bacterial overgrowth, essentially of Gram-negative bacilli. After recovery, the only remaining alteration was the frequent isolation of yeast-like fungi in low concentrations. Infants with acute diarrhoea, except for the isolation more frequently of yeast-like fungi, presented no alterations; this seems to indicate that pH alterations and Gram-negative bacilli overgrowth occurred during the evolution of the disease to a chronic state. Breast-fed normal infants had hydrogen-ion concentrations similar to those of the chronic diarrhoea group, but without Gram-negative bacilli overgrowth, suggesting that other factors, besides pH, regulate bacterial growth in the gastric contents of these groups of infants.

https://gut.bmj.com/content/gutjnl/16/9/719.full.pdf

Gastric pH and microflora of normal and diarrhoeic infants.

Triple-negative breast cancer (TNBC) is a subtype of breast cancer with high risk of distant metastasis, in which the intercellular communication between tumor cells also plays a role. Exosomes can be released by tumor cells and promote distant metastasis through intercellular communication or changes in tumor microenvironment, it is an optimized transportation facility for biologically active payloads. This was a hypothesis-generating research on role of exosomal payload in TNBC distant metastasis.Exosomes isolated from supernatant of MDA-MB-231 and MDA-MB-231-HM (a highly pulmonary metastatic variant of parental MDA-MB-231 cells) were characterized. MMP-1 level was detected using mass spectrometry and western blot. Transwell assay, wound healing and CCK-8 assay were employed to explore the effect of exosomal MMP-1 on the metastatic capability of TNBC cells in vitro. Human breast cancer lung metastasis model in nude mice was established to observe the effect of exosomal MMP-1 in vivo. Tissue microarray and blood samples of TNBC patients were applied to analyze the relevance between MMP-1 with metastasis.MDA-MB-231-HM cells secrete exosomes enriched MMP-1, which can be taken up and enhance invasion and migration activities of TNBC cells, including MDA-MB-231, MDA-MB-468 and BT549. After ingesting exosomes enriched with MMP-1, cells secret more MMP-1, which may interact with membrane G protein receptor protease activated receptor 1 (PAR1), thereby initiating epithelial-mesenchymal transition (EMT) to enhance capability of migration and invasion. The lung colonization model shows that the expressions of MMP-1 and PAR1 in the metastases of the 231-HM-exo treated mice were both upregulated. Clinically, the enrichment of MMP-1 can be detected in exosomes extracted from serum of patients with metastasis at higher concentration than that in pre-operative patients. Moreover, in patients with multiple distant metastases, the level of MMP-1 in exosomes is also higher than that in patients with single lesion.MMP-1 from TNBC cells of high metastasis potential can promote the distant metastasis of transform those with low metastasis potential through PAR1-mediated EMT and is likely to be a potential molecular marker. 

https://www.researchsquare.com/article/rs-751066/latest.pdf

Exosomal MMP-1 transfers metastasis potential in triple-negative breast cancer through PAR1-mediated EMT

Research on the roles of the bacteria in tumor development and progression is a rapidly emerging field. Increasing evidence links bacteria with the modification of the tumor immune microenvironment, which greatly influences the antitumor response. In view of the individual immune effects of various bacteria in various tumors, developing personalized bacteria-modulating therapy may be a key to successful antitumor treatment. This review emphasizes the critical role of the bacteria in immune regulation, including both the tumor bacteria and gut bacteria. Aiming at tumor-related bacteria, we focus on various precise modulation strategies and discuss their impact and potential for tumor suppression. Finally, engineered bacteria with tumor-targeting ability could achieve precise delivery of various payloads into tumors, acting as a precision tool. Therefore, a precise tumor-related bacteria therapy may be a promising approach to suppress the development of tumors, as well as an adjuvant therapy to improve the antitumor efficacy of other approaches. KEY POINTS: • The mini-review updates the knowledge on complex effect of bacteria in TME. • Insight into the interaction and adjustment of bacteria in gut for TME. • Prospects and limitations of bacteria-related personalized therapy in the clinical anticancer therapy.

Precision strategies for cancer treatment by modifying the tumor-related bacteria

The iconic Tasmanian devil (Sarcophilus harrisii) is endangered due to the transmissible cancer Devil Facial Tumour Disease (DFTD), of which there are two genetically independent subtypes (DFT1 and DFT2). While DFT1 and DFT2 can be differentially diagnosed using tumour biopsies, there is an urgent need to develop less-invasive biomarkers that can detect DFTD and distinguish between subtypes. Extracellular vesicles (EVs), the nano-sized membrane-enclosed vesicles present in most biofluids, represent a valuable resource for biomarker discovery. Here, we characterized the proteome of EVs from cultured DFTD cells using data-independent acquisition–mass spectrometry and an in-house spectral library of > 1500 proteins. EVs from both DFT1 and DFT2 cell lines expressed higher levels of proteins associated with focal adhesion functions. Furthermore, hallmark proteins of epithelial–mesenchymal transition were enriched in DFT2 EVs relative to DFT1 EVs. These findings were validated in EVs derived from serum samples, revealing that the mesenchymal marker tenascin-C was also enriched in EVs derived from the serum of devils infected with DFT2 relative to those infected with DFT1 and healthy controls. This first EV-based investigation of DFTD increases our understanding of the cancers’ EVs and their possible involvement in DFTD progression, such as metastasis. Finally, we demonstrated the potential of EVs to differentiate between DFT1 and DFT2, highlighting their potential use as less-invasive liquid biopsies for the Tasmanian devil.

Extracellular vesicle proteomes of two transmissible cancers of Tasmanian devils reveal tenascin-C as a serum-based differential diagnostic biomarker

IgA in the gastric content and in the serum of eutrophic and malnourished infants

Depending on quantity and/or quality, the presence of lactic acid in the colonic lumen may be associated with metabolic damage of the colon. The influence exerted on the rat colon by the different isomers and racemic of the lactic acid, used at two extreme dilutions (20 and 100 mEq/l), has been the subject of study in this paper. The modifications on pH, water and electrolytes are associated with the absorptive/secretory action of the colonic wall. In addition, a study has been made on the influence of lactic acid on the colonic mucus and albumin permeation. Histopathologic studies of the caecum and left colon have been performed. There is a different colonic wall behaviour for each of the different isomers of the lactic and its racemic; a larger absorption of water, Na+ and Cl- for the D (-) isomer at a low concentration; its behaviour is completely opposite at high concentration. The final pH is higher when the D (-) isomer takes part; comparing the different isomers, there are small variations as far as albumin permeation is concerned. At high concentration there is a decline in Cl- absorption. The high percentage of erosions that take place especially in the caecum, where L (+) isomer can be found at high concentration, it is remarkable. The present observations suggest that the presence of lactic acid in (the) ulcerative colitis deserves great attention, especially in about the quantity and quality in which the acid can be found.

González E

Papers

IgA in the gastric content and in the serum of eutrophic and malnourished infants

La acción de los diferentes isómeros del acido láctico en el colón de la rata