# Producing highly effective extracellular vesicles using IBAR and talin F3 domain fusion

## TL;DR

This study introduces a fusion protein that boosts extracellular vesicle production and enhances their uptake by target cells.

## Contribution

The novel IBAR-F3 fusion protein increases EV production and promotes integrin-dependent uptake.

## Key findings

- IBAR-F3 induces filopodia-like membrane protrusions and attracts integrins to those regions.
- EVs produced with IBAR-F3 are efficiently taken up by nearby cells in an integrin-dependent manner.
- IBAR-F3 activates integrins by inducing negative membrane curvature.

## Abstract

Extracellular vesicles (EVs), transporting diverse cellular components, play a crucial role in intercellular communication in numerous physiological and pathological processes. EVs have also been recognized as a drug delivery platform for therapeutic purposes and cell-free regenerative medicine. While various approaches have focused on increasing EV production for efficient use therapeutic use of EVs, enhancing the quality of EVs, such as ensuring efficient uptake by their target cells, has not been widely explored. In this study, we linked a negative membrane curvature-forming inverse BAR (IBAR) domain with an integrin β tail-binding talin F3 domain to create the IBAR-F3 fusion protein. We observed that IBAR-F3 can trigger filopodia-like membrane protrusions and attract integrins to those protrusion-rich regions, when expressed in Chinese hamster ovary cells expressing integrin αIIbβ3. Surprisingly, the expression of IBAR-F3 also induced a robust production of EVs, which were then efficiently taken up by nearby cells in an integrin-dependent manner. Moreover, IBAR triggered integrin activation, presumably by inducing negative membrane curvature that likely disrupts the interaction between the integrin α and β transmembrane domain. Therefore, we suggest that IBAR-F3 should be utilized to promote both EV production and efficient uptake mediated by integrins. Furthermore, the negative curvature-inducing integrin activation suggests that integrins on EVs can be activated by the nanoscale change in the curvature of the EV without the need for conventional machinery to activate integrin inside the EVs.