Biology subjects

Harmon, J. W.

Publications and source records attributed to Harmon, J. W..

3 recordsLinked to original sources

bioRxiv2023

Induced pluripotent stem cell-derived extracellular vesicles promote wound repair in a diabetic mouse model via an anti-inflammatory immunomodulatory mechanism

Extracellular vesicles (EVs) derived from mesenchymal stem/stromal cells (MSCs) have recently been widely explored in clinical trials for treatment of diseases with complex pathophysiology. However, production of MSC EVs is currently hampered by donor-specific characteristics and limited ex vivo expansion capabilities before decreased potency, thus restricting their potential as a scalable and reproducible therapeutic. Induced pluripotent stem cells (iPSCs) represent a self-renewing source for obtaining differentiated iPSC-derived MSCs (iMSCs), circumventing both scalability and donor variability concerns for therapeutic EV production. Thus, we initially sought to evaluate the therapeutic potential of iMSC EVs. Interestingly, while utilizing undifferentiated iPSC EVs as a control, we found that their vascularization bioactivity was similar and their anti-inflammatory bioactivity was superior to donor-matched iMSC EVs in cell-based assays. To supplement this initial in vitro bioactivity screen, we employed a diabetic wound healing mouse model where both the pro-vascularization and anti-inflammatory activity of these EVs would be beneficial. In this in vivo model, iPSC EVs more effectively mediated inflammation resolution within the wound bed. Combined with the lack of additional differentiation steps required for iMSC generation, these results support the use of undifferentiated iPSCs as a source for therapeutic EV production with respect to both scalability and efficacy.

bioengineering↗

bioRxiv2022

Mesenchymal stem cell culture within perfusion bioreactors incorporating 3D-printed scaffolds enables improved extracellular vesicle yield with preserved bioactivity

Extracellular vesicles (EVs) are implicated as promising therapeutics and drug delivery vehicles in various diseases. However, successful clinical translation will depend on development of scalable biomanufacturing approaches, especially due to the documented low levels of intrinsic EV-associated cargo that may necessitate repeated doses to achieve clinical benefit in certain applications. Thus, here we assessed effects of a 3D-printed scaffold-perfusion bioreactor system on the production and bioactivity of EVs secreted from bone marrow-derived mesenchymal stem cells (MSCs), a cell type heavily implicated in generating EVs with therapeutic potential. Our results indicate that perfusion bioreactor culture results in an ~40-80-fold increase, depending on measurement method, in MSC EV production compared to conventional cell culture. Additionally, we demonstrated that MSC EVs generated using the bioreactor system significantly improved wound healing in a diabetic mouse model, with increased CD31+ staining in wound bed tissue compared to animals treated with flask cell culture-generated MSC EVs. Overall, this study establishes a promising solution to major EV translational issues (i.e., scalability and low potency) with potential for adaptation to various EV-based therapeutics and capacity for improvement alongside the continuous advancements in 3D-printing technologies.

bioengineering↗

bioRxiv2022

The Impact of Storage Condition and Duration on Function of Native and Cargo-Loaded Mesenchymal Stromal Cell Extracellular Vesicles

As evidenced by ongoing clinical trials and increased activity in the commercial sector, extracellular vesicle (EV)-based therapies have begun the transition from bench to bedside. As this progression continues, one critical aspect to EV clinical translation is understanding the effects of storage and transport conditions. Several studies have assessed the impact of storage on EV characteristics such as morphology, uptake, and component content, but effects of storage duration and temperature on EV functional bioactivity and, especially, loaded cargo are scarcely reported. Here, EV outcomes following storage at different temperatures (room temperature, 4{degrees}C, -20{degrees}C, -80{degrees}C) for various durations as well as after lyophilization were assessed. Mesenchymal stem/stromal cell (MSC) EVs were observed to retain key aspects of their bioactivity (pro-vascularization, anti-inflammation) for up to 4-6 weeks at -20{degrees}C, -80{degrees}C, and after lyophilization. Furthermore, via in vitro assays and an in vivo wound healing model respectively, these same storage conditions were also demonstrated to enable preservation of the functionality of loaded microRNA (miRNA) as well as long non-coding RNA (lncRNA) cargo in MSC EVs. These findings extend the current understanding of how EV therapeutic potential is impacted by storage conditions and may inform best practices for handling and storage of MSC EVs for both basic research and translational purposes.

bioengineering↗