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Extracellular vesicles (EVs) derived from mesenchymal stem/stromal cells (MSCs) have been recognized as promising cytotherapeutics due to their demonstrated immunomodulatory effects in various preclinical models. The immunomodulatory capabilities of EVs stem from the proteins and genetic materials they carry from parent cells, but the cargo contents of EVs are significantly influenced by MSC tissues and donors, cellular age and culture conditions, resulting in functional variations. However, there are no surrogate assays available to validate the immunomodulatory potency of MSC‐EVs before in vivo administration. In previous work, we discovered that microcarrier culture conditions enhance the immunomodulatory function of MSC‐EVs, as well as the levels of immunosuppressive molecules such as TGF‐β1 and let‐7b in MSC‐EVs. Building on these findings, we investigated whether TGF‐β1 levels in MSC‐EVs could serve as a surrogate biomarker for predicting their potency in vivo. Our studies revealed a strong correlation between TGF‐β1 and let‐7b levels in MSC‐EVs, as well as their capacity to suppress IFN‐γ secretion in stimulated splenocytes, establishing biopotency and surrogate assays for MSC‐EVs. Subsequently, we validated MSC‐EVs generated from monolayer cultures (ML‐EVs) or microcarrier cultures (MC‐EVs) using murine models of experimental autoimmune uveoretinitis (EAU) and additional in vitro assays reflecting the Mode of Action of MSC‐EVs in vivo. Our findings demonstrated that MC‐EVs carrying high levels of TGF‐β1 exhibited greater efficacy than ML‐EVs in halting disease progression in mice with EAU as well as inducing apoptosis and inhibiting the chemotaxis of retina‐reactive T cells. Additionally, MSC‐EVs suppressed the MAPK/ERK pathway in activated T cells, with treatment using TGF‐β1 or let‐7b showing similar effects on the MAPK/ERK pathway. Collectively, our data suggest that MSC‐EVs directly inhibit the infiltration of retina‐reactive T cells toward the eyes, thereby halting the disease progression in EAU mice, and their immunomodulatory potency in vivo can be predicted by their TGF‐β1 levels.

Human mesenchymal stem cells (hMSCs) are effective in treating disorders resulting from an inflammatory or heightened immune response. The hMSCs derived from induced pluripotent stem cells (ihMSCs) share the characteristics of tissue derived hMSCs but lack challenges associated with limited tissue sources and donor variation. To meet the expected future demand for ihMSCs, there is a need to develop scalable methods for their production at clinical yields while retaining immunomodulatory efficacy. Herein, we describe a platform for the scalable expansion and rapid harvest of ihMSCs with robust immunomodulatory activity using degradable gelatin methacryloyl (GelMA) microcarriers. GelMA microcarriers were rapidly and reproducibly fabricated using a custom microfluidic step emulsification device at relatively low cost. Using vertical wheel bioreactors, 8.8 to 16.3‐fold expansion of ihMSCs was achieved over 8 days. Complete recovery by 5‐minute digestion of the microcarriers with standard cell dissociation reagents resulted in >95% viability. The ihMSCs matched or exceeded immunomodulatory potential in vitro when compared with ihMSCs expanded on monolayers. This is the first description of a robust, scalable, and cost‐effective method for generation of immunomodulatory ihMSCs, representing a significant contribution to their translational potential. A scalable system for the generation and rapid harvest of immunomodulatory induced pluripotent stem cell‐derived mesenchymal stem cells..

We investigated the use of termite baiting, a proven system of targeted colony elimination, in an overall area-wide control strategy against subterranean termites. At two field sites, we used microsatellite markers to estimate the total number of Reticulitermes colonies, their spatial partitioning, and breeding structure. Termite pressure was recorded for two years before and after the introduction of Trelona® (active ingredient novaluron) to a large area of one of the sites. Roughly 70% of the colonies in the treatment site that were present at the time of baiting were not found in the site within two months after the introduction of novaluron. Feeding activity of the remaining colonies subsequently ceased over time and new invading colonies were unable to establish within this site. Our study provides novel field data on the efficacy of novaluron in colony elimination of Reticulitermes flavipes, as well as evidence that an area-wide baiting program is feasible to maintain a termite-free area within its native range.

BackgroundOsteosarcoma (OS) is the most common primary bone malignancy. Chemotherapy plays an essential role in OS treatment, potentially doubling 5-year event-free survival if tumour necrosis can be stimulated. The canonical Wnt inhibitor Dickkopf-1 (Dkk-1) enhances OS survival in part through upregulation of aldehyde-dehydrogenase-1A1 which neutralises reactive oxygen species originating from nutritional stress and chemotherapeutic challenge.MethodsA vivo morpholino (DkkMo) was employed to block the expression of Dkk-1 in OS cells. Cell mitosis, gene expression and bone destruction were measured in vitro and in vivo in the presence and absence of doxorubicin (DRB).ResultsDkkMo reduced the expression of Dkk-1 and Aldh1a1, reduced expansion of OS tumours, preserved bone volume and architecture and stimulated tumour necrosis. This was observed in the presence or absence of DRB.ConclusionThese results indicate that administration of DkkMo with or without chemotherapeutics can substantially improve OS outcome with respect to tumour expansion and osteolytic corruption of bone in experimental OS model.