Klotho peptide-engineered red blood cell EVs protect kidneys from fibrosis by suppressing TGFβ/SMAD signaling

Chronic kidney disease is characterized by progressive tubular injury and fibrosis, leading to irreversible loss of renal function. Current therapeutic strategies often fall short in effectively halting this progression. Extracellular vesicles (EVs) offer a promising platform due to their biocompatibility and ability to deliver therapeutic cargo. This study explores the potential of engineering EVs to deliver an active peptide from klotho, an anti-aging hormone, as a targeted antifibrotic approach to address this unmet need in kidney disease.

Researchers engineered red blood cell-derived EVs (RBC-EVs) by surface-functionalizing them with an active klotho peptide (termed RBC-EVKP1). The antifibrotic efficacy was evaluated in two in vitro models: proximal tubular epithelial cells exposed to TGFβ to induce fibrosis, and a 3D proximal tubule-on-chip system. The primary endpoints included assessing fibrotic and mesenchymal gene expression, extracellular matrix accumulation, SMAD signaling, cell migration, and epithelial organization following RBC-EVKP1 treatment.

Treatment with RBC-EVKP1 significantly attenuated TGFβ-induced fibrotic and mesenchymal gene expression in proximal tubular epithelial cells. This intervention also reduced extracellular matrix accumulation and suppressed SMAD signaling, a key pathway in fibrosis. Furthermore, RBC-EVKP1 treatment reduced cell migration and preserved epithelial organization, indicating a protective effect on cellular structure and function. In the more complex 3D tubule-on-chip system, the engineered EVs successfully maintained cytoskeletal integrity and reduced injury-associated marker expression under fibrotic conditions. This collective evidence points to a robust antifibrotic mechanism.

RBC-EVKP1 treatment significantly attenuated TGFβ-induced fibrotic and mesenchymal gene expression, demonstrating a potent antifibrotic effect.