Comparison of methods for separating fluorescently labelled placental extracellular vesicles from free stain

Dietary Lactobacillus rhamnosus GG extracellular vesicles enhance antiprogrammed cell death 1 (anti-PD-1) immunotherapy efficacy against colorectal cancer

There is a need to explore combination therapy to improve the efficacy of immunotherapy for colorectal cancer through food probiotics. In this study, extracellular vesicles (EV) derived from Lactobacillus rhamnosus GG (LGG-EV) were successfully isolated. Adjusting the culture temperature to 30 °C led to an elevated LGG-EV yield, and the addition of penicillin resulted in a decrease in particle size. In addition, LGG-EV have better gastrointestinal tract stability in a Ca2+ environment in vivo and in vitro. Oral administration of LGG-EV synergistically improved anti-PD-1 immunotherapy efficacy against colorectal cancer. Mechanistically, LGG-EV modulated intestinal immunity by increasing the CD8+ T/CD4+ T cell ratio in mesenteric lymph nodes and enhancing the ratio of MHC II+ DC cells, CD4+ T cells, and CD8+ T cells in tumor tissues. Meanwhile, the diversity of the gut microbiota and the abundance of beneficial bacteria, such as Lactobacillus, increased in the combined-treatment mice. In addition, there were significant changes in the levels of serum metabolites associated with the microbiota and anti-tumor effects, including uridine, which was elevated by the combination of anti-PD-1 and LGG-EV treatment. Our findings provide theoretical and mechanistic insights into the development of LGG-EV as postbiotics in combination with immune checkpoint inhibitors for cancer therapy.

Studying exogenous extracellular vesicle biodistribution by in vivo fluorescence microscopy

Extracellular vesicles (EVs) are lipid-bound vesicles released from cells that play a crucial role in many physiological processes and pathological mechanisms. As such, there is great interest in their biodistribution. One currently accessible technology to study their fate in vivo involves fluorescent labelling of exogenous EVs followed by whole-animal imaging. Although this is not a new technology, its translation from studying the fate of whole cells to subcellular EVs requires adaptation of the labelling techniques, excess dye removal and a refined experimental design. In this Review, we detail the methods and considerations for using fluorescence in vivo and ex vivo imaging to study the biodistribution of exogenous EVs and their roles in physiology and disease biology.

Extracellular Vesicles Derived From Stem Cells in Intervertebral Disc Degeneration

Intervertebral disc degeneration (IVDD) is the leading cause of low back pain related to degradation of cartilaginous tissues, mainly resulting from oxidative stress, cell apoptosis, and extracellular matrix degradation. Extracellular vesicles (EVs) exist in all bodily fluids and can be produced by all types of cells. Stem cell-derived EVs (SC-EVs), which are the main paracrine components of stem cells, have gained significant attention in the field of regenerative medicine. Over the past years, accumulating evidence indicates the therapeutic and diagnostic potentials of EVs in IVDD. The main mechanisms involve the induction of regenerative phenotypes, apoptosis alleviation, and immune modulation. In addition, the efficiency of SC-EVs can be enhanced by choosing appropriate donor cells and cell phenotypes, optimizing cell culture conditions, or engineering EVs to deliver drugs and targeting molecules. Given the importance and novelty of SC-EVs, we give an overview of SC-EVs and discuss the roles of SC-EVs in IVDD.