Johann Mar Gudbergsson

A comprehensive overview of exosomes as drug delivery vehicles - endogenous nanocarriers for targeted cancer therapy.

Exosomes denote a class of secreted nanoparticles defined by size, surface protein and lipid composition, and the ability to carry RNA and proteins. They are important mediators of intercellular communication and regulators of the cellular niche, and their altered characteristics in many diseases, such as cancer, suggest them to be important both for diagnostic and therapeutic purposes, prompting the idea of using exosomes as drug delivery vehicles, especially for gene therapy. This review covers the current status of evidence presented in the field of exosome-based drug delivery systems. Components for successful exosome-based drug delivery, such as choice of donor cell, therapeutic cargo, use of targeting peptide, loading method and administration route are highlighted and discussed with a general focus pertaining to the results obtained in models of different cancer types. In addition, completed and on-going clinical trials are described, evaluating exosome-based therapies for the treatment of different cancer types. Due to their endogenous origin, exosome-based drug delivery systems may have advantages in the treatment of cancer, but their design needs further refinement to justify their usage on the clinical scale.

Systematic review of factors influencing extracellular vesicle yield from cell cultures

The potential therapeutic utility of extracellular vesicles (EVs) has spawned an interest into a scalable production, where the quantity and purity of EV samples is sufficient for clinical applications. EVs can be isolated using several different protocols; however, these isolation protocols and the subsequent methods of quantifying the resulting EV yield have not been sufficiently standardized. Therefore, the possibility of comparing different studies with respect to these parameters is limited. In this review, we have presented factors that might influence the yield and function of EVs from cell culture supernatants. The methods of isolation, downstream quantification, and culture conditions of the EV producing cells have been discussed. In order to examine the inter-study coherency of EV yields, 259 studies were initially screened, and 46 studies were included for extensive downstream analysis of EV yields where information pertaining to the isolation protocols and quantification methods was obtained from each study. Several other factors influencing yield were compared, such as cell type producing EVs, cell confluence level, and cell stimulation. In conclusion, various factors may impact the resulting EV yield, including technical aspects such as EV isolation and quantification procedures, and biological aspects such as cell type and culture conditions. The reflections presented in this review might aid in future standardization of the workflow in EV research.

Evaluation of electroporation-induced adverse effects on adipose-derived stem cell exosomes

In the recent years, the possibility of utilizing extracellular vesicles for drug delivery purposes has been investigated in various models, suggesting that these vesicles may have such potential. In addition to the choice of donor cell type for vesicle production, a major obstacle still exists with respect of loading the extracellular vesicles efficiently with the drug of choice. One of the proposed solutions to this problem has been drug loading by electroporation, where small pores are created in the membrane of the extracellular vesicles, hereby allowing for free diffusion of the drug compound into the interior of the vesicle. We investigated the utility of adipose-derived stem cells (ASCs) as an efficient exosome donor cell type with a particular focus on the treatment of glioblastoma multiforme (GBM). In addition, we evaluated electroporation-induced effects on the ASC exosomes with respect to their endogenous potential of stimulating GBM proliferation, and morphological changes to single and multiple ASC exosomes. We found that electroporation does not change the endogenous stimulatory capacity of ASC exosomes on GBM cell proliferation, but mediates adverse morphological changes including aggregation of the exosomes. In order to address this issue, we have successfully optimized the use of a trehalose-containing buffer system as a way of maintaining the structural integrity of the exosomes.

On the use of liposome controls in studies investigating the clinical potential of extracellular vesicle-based drug delivery systems: A commentary

The field of extracellular vesicle (EV)-based drug delivery systems has evolved significantly through the recent years, and numerous studies suggest that these endogenous nanoparticles can function as efficient drug delivery vehicles in a variety of diseases. Many characteristics of these EV-based drug delivery vehicles suggest them to be superior at residing in the systemic circulation and possibly at mediating therapeutic effects compared to synthetic drug delivery vehicles, e.g. liposomes. In this Commentary, we discuss how some currently published head-to-head comparisons of EVs versus liposomes are weakened by the inadequate choice of liposomal formulation, and encourage researchers to implement better controls to show any potential superiority of EVs over other synthetic nanoparticles.

Extracellular Vesicles From Mesenchymal Stem Cells and Their Potential in Tumor Therapy

This chapter is focused on the utility of extracellular vesicles (EVs) from mesenchymal stem/stromal cells (MSCs) as therapeutics to target tumor growth. In order to provide an introduction to the field, the biology of EVs and subsequent characterization have been presented, providing a basic overview. Much of what is known about tumor biology and the respective cancer hallmarks is highlighted in the context of EVs playing a major role in tumor progression. Cell-to-cell communication in the form of paracrine signaling for both tumor cells and MSCs can be aligned, and a number of studies have investigated the effects of MSCs on respective tumor hallmarks. The clinical utility of MSC as therapeutics and the various avenues of targeting have been summarized and critically appraised with respect to future therapeutic intervention.

GBM extracellular vesicles: mediators of invasion and brain stromal modulation

Extracellular vesicles (EVs) have a demonstrated involvement in modulating the immune system. It has been proposed that EVs could be used as biomarkers for detection of inflammatory and immunological disorders. Consequently, it is of great interest to investigate EVs in more detail with focus on immunological markers. In this study, five major leukocyte subpopulations and the corresponding leukocyte-derived EVs were phenotyped with focus on selected immunological lineage-specific markers and selected vesicle-related markers. The leukocyte-derived EVs displayed phenotypic differences in the 34 markers investigated. The majority of the lineage-specific markers used for identification of the parent cell types could not be detected on EVs released from monocultures of the associated cell types. In contrast, the vesicular presentation of CD9, CD63, and CD81 correlated to the cell surface expression of these markers, however, with few exceptions. Furthermore, the cellular expression of CD9, CD63, and CD81 varied between leukocytes present inwhole blood and cultured leukocytes. In summary, these data demonstrate that the cellular and vesicular presentation of selected lineage-specific and vesicle-relatedmarkersmay differ, supporting the accumulating observations that sorting of molecular cargo into EVs is tightly controlled.ISEV2016 is organized by The Local Organizing Committee Chair Edit I Buzás (Hungary), Aled Clayton (United Kingdom), Dolores Di Vizio (USA), Juan Manuel Falcon-Perez (Spain), Guido Jenster (The Netherlands), Lorraine O’Driscoll (Ireland), Yong Song Gho (South Korea), Marjolein van Driel (The Netherlands), Hans van Leeuwen (The Netherlands), Guillaume van Niel (France), Marca HM Wauben (The Netherlands), Kenneth W Witwer (USA), María Yáñez-Mó (Spain) Together with the Executive ISEV Board (2014 – 2016) President: Jan Lötvall Secretary General: Clotilde Théry Interim Treasurer: Kenneth W Witwer Executive Chair Science / Meetings: Marca Wauben Executive Chair Education: Yong Song Gho Executive Chair Communication: Andrew Hill Members at Large: Peter Quesenberry, Kenneth W Witwer, Susmita Sahoo, Dolores Di Vizio, Chris Gardiner, Edit I Buzás, Hidetoshi Tahara, Suresh Mathivanan, Igor Kurochkin

Extracellular vesicles from glioblastoma cells as potential drug-delivery vehicles to isotypic tumours

Introduction: Besides providing nutrition, breast milk delivers important signals that stimulate the infants developing immune system. It has been postulated that extracellular vesicles (EV) in milk support the instruction and/or development of neonatal immunity. However, little is known about the composition of milk-derived EV, partly due to the difficulty to purify EV from other components in milk. Methods: In this study, an extensive LC-MS/MS proteomic analysis was performed, whereby EV were isolated from breast milk of 7 individual donors using our recently established optimized density gradient-based isolation protocol [1]. High-density, non-floating complexes were included to compare the contents of EV to other macromolecular structures in milk. A comprehensive protein network was composed tracing the possible cellular origins of milk-derived EV and the potential targets in the gut. Results: An average of 579 proteins was identified in EV, compared to 205 proteins in the non-floating fraction. Interestingly, EV associated proteins like ANXA5 and Flotillin were exclusively identified in EV, while CD9, CD63 and CD81 were also present in non-floating protein complexes. Additionally, MHC-II was identified in the EV fraction only, suggesting that antigenic epitopes may be delivered via EV released from antigen-presenting cells. Besides MHC-I, the mammary epithelial cell marker beta-1,4-galactosyltransferase (lactose subunit) was identified in the EV fraction only, demonstrating EV of epithelial origin. Furthermore, several adhesion molecules (ICAM-1, CEACAM-1) were associated to EV which could allow EV binding to gut epithelial cells and gut resident immune cells. Summary/conclusion: In-depth proteomic analysis and compilation of an extensive network of EV proteins involved in immunity demonstrates that milk-derived EV originate from multiple cellular sources and have the ability to target various cell types in the gut.ISEV 2015 is organized by The Local Organizing Committee: Kenneth Witwer (Chair, Baltimore), Shilpa Buch (Omaha), Prasun Datta (Philadelphia), Dolores Di Vizio (Los Angeles), Uta Erdbrügger (Charlottesville), Steven Jay (College Park), Dimitrios Kapogiannis (Baltimore), Leonid Margolis (Bethesda) & Susmita Sahoo (New York) Together with the Executive ISEV Board (2014 – 2016) President: Jan Lötvall Secretary General: Clotilde Théry Treasurer: Fred Hochberg Executive Chair Science / Meetings: Marca Wauben Executive Chair Education: Yong Song Gho Executive Chair Communication: Andrew Hill Members at Large: Peter Quesenberry, Kenneth Witwer, Susmita Sahoo, Dolores Di Vizio, Chris Gardiner, Edit Buzas, Hidetoshi Tahara, Suresh Mathivanan, Igor Kurochkin

The potential of adipose-derived stem cell exosomes as vehicles of drug delivery

ISEV 2014 is organized by Local Organizing Committee: Marca Wauben (Utrecht), Raymond Schiffelers (Utrecht), Michiel Pegtel (Amsterdam), Rienk Nieuwland (Amsterdam), Hans van Leeuwen (Rotterdam) & Esther Nolte-’t Hoen (Utrecht) Together with Executive ISEV Board (2012 – 2014) President: Jan Lötvall Secretary General: Clotilde Théry Treasurer: Janusz Rak Members at Large: Yong Song Gho, Dwidjendra Gupta, Andrew Hill, Fred Hochberg, Peter Quesenberry, Lawrence Rajendran, Douglas Taylor, Marca Wauben Adjunct members: Chris Gardiner, Melissa Piper †, Hidetoshi Tahara Diamond Sponsor: Caris Life Sciences

Characterization of protein expression on glioblastoma multiforme exosomes and evaluation of methods for their isolation

ISEV 2014 is organized by Local Organizing Committee: Marca Wauben (Utrecht), Raymond Schiffelers (Utrecht), Michiel Pegtel (Amsterdam), Rienk Nieuwland (Amsterdam), Hans van Leeuwen (Rotterdam) & Esther Nolte-’t Hoen (Utrecht) Together with Executive ISEV Board (2012 – 2014) President: Jan Lötvall Secretary General: Clotilde Théry Treasurer: Janusz Rak Members at Large: Yong Song Gho, Dwidjendra Gupta, Andrew Hill, Fred Hochberg, Peter Quesenberry, Lawrence Rajendran, Douglas Taylor, Marca Wauben Adjunct members: Chris Gardiner, Melissa Piper †, Hidetoshi Tahara Diamond Sponsor: Caris Life Sciences