At the time of writing, it has been less than two years since the Exoid has been released. Given the time it takes for research to progress, there is always a lag between the release of an instrument and seeing it feature in a published journal article. Despite this, we have been delighted to see Exoid publications arrive into our inboxes. Here are three of our favourite papers where researchers have used the Exoid to analyse extracellular vesicles (EVs).
Paper title: Extracellular Vesicle Secretion by Leukemia Cells In Vivo Promotes CLL Progression by Hampering Antitumor T-cell Responses1
Key research question: Chronic lymphatic leukemia (CLL) requires an immunosuppressive environment for disease progression, but how does it craft this environment?
What did they find out? Due to an increase in the expression of genes involved in EV biogenesis in human and mouse CCL cells, Gargiulo et al (2022) hypothesised that there may be more EVs in the leukemia microenvironment (LME) than in healthy spleens. Indeed, they managed to validate and quantify this increase in LME EVs using the Exoid (Figure 1A).
These LME EVs then altered CD8+ T cells in vivo in an anti-inflammatory manner, leading to decreased cytotoxicity against CCL cells. Furthermore, when CCL cells from a Rab27 knockout mouse (i.e., depleted in EV biogenesis) were transplanted into mice, disease progression was dramatically inhibited as compared to wild-type CCL cells (Figure 1C). This inhibition was reversed by the addition of LME EVs from wild-type CCL cells.
The bottom line? Using the Exoid, Gargiulo et al. were able to critically detect an increased concentration of EVs in the LME which led to the determination that these EVs promote CLL progression via immune modulation.
Paper title: Extracellular Vesicles Derived from Bone Marrow in an Early Stage of Ionizing Radiation Damage Are Able to Induce Bystander Responses in the Bone Marrow2
Key research question: Irradiated cells can transmit negative effects to neighbouring cells via EVs in the bystander effect. Can bone marrow cells of irradiated animals transmit negative effects to stem cells of non-irradiated mice?
What did they find out? Irradiating mice increased the numbers of EVs released by bone marrow cells at 24 hours and, more surprisingly, at three months post irradiation (Figure 2A). Both irradiation itself and injection with the bone marrow EVs from irradiated animals reduced the numbers of haematopoietic stem cells, lymphoid progenitor cells and mesenchymal stem cells. Some of these effects remained at three months.
Furthermore, bone marrow haematopoietic stem cells, lymphoid progenitor cells and mesenchymal stem cells were apoptotic four hours after irradiation (Figure 2B). For haematopoietic stem cells and lymphoid progenitor cells, a similar increase in apoptosis was seen in non-irradiated mice four hours after injection with EVs from irradiated mice. This suggests that bone marrow derived EVs perpetuate cell death in irradiated organisms.
The bottom line? Using the Exoid to gain precise measures of EV concentration, Kis et al. were able to detect a dose-response increase in bone marrow EVs with increasing irradiation doses to mice. These EVs had a negative impact on other bone marrow cells, even when injected into non-irradiated mice, demonstrating the bystander effect.
Paper title: Bio-Pulsed Stimulation Effectively Improves the Production of Avian Mesenchymal Stem Cell-Derived Extracellular Vesicles That Enhance the Bioactivity of Skin Fibroblasts and Hair Follicle Cells3
Key research question: Mesenchymal stem cell EVs have been shown to improve skin wound healing and hair follicle health. Can avian mesenchymal stem cells be used as a cheap source of EVs and will “bio-pulsing” with Polygonum multiflorum extract improve their effectiveness?
What did they find out? Avian stem cells from chicks were cultured in the presence (bio-pulsed) or absence (control) of Polygonum multiflorum extract. Bio-pulsing significantly improved EV yield (Figure 3A) and trended towards reducing mean EV diameter (Figure 3B). Human skin fibroblast proliferation was increased with equal amounts (µg) of EV isolates from bio-pulsed cells as compared to control cells. In vitro, this translated into increased fibroblasts in the wound area following a scratch assay (Figure 3C). Additionally, expression of collagen genes was increased, LPS-challenged inflammation was decreased, hair follicle cell gene expression was altered in a beneficial manner.
The bottom line? Avian mesenchymal stem cell EVs were beneficial in a number of skin-based assays. By using the Exoid, the group identified that bio-pulsing with Polygonum multiflorum extract increased EV production. Bio-pulsing also improved beneficial skin effects, suggesting that Polygonum multiflorum extract may be of use in therapeutic EV production.