Differentiated kidney tubular cell-derived extracellular vesicles enhance maturation of tubuloids

Abstract

The prevalence of end-stage kidney disease (ESKD) is rapidly increasing with the need for regenerative therapies. Adult stem cell derived kidney tubuloids have the potential to functionally mimic the adult kidney tubule, but still lack the expression of important transport proteins needed for waste removal. Here, we investigated the potential of extracellular vesicles (EVs) obtained from matured kidney tubular epithelial cells to modulate in vitro tubuloids functional maturation. We focused on organic anion transporter 1 (OAT1), one of the most important proteins involved in endogenous waste excretion. First, we show that EVs from engineered proximal tubule cells increased the expression of several transcription factors and epithelial transporters, resulting in improved OAT1 transport capacity. Next, a more in-depth proteomic data analysis showed that EVs can trigger various biological pathways, including mesenchymal-to-epithelial transition, which is crucial in the tubular epithelial maturation. Moreover, we demonstrated that the combination of EVs and tubuloid-derived cells can be used as part of a bioartificial kidney to generate a tight polarized epithelial monolayer with formation of dense cilia structures. In conclusion, EVs from kidney tubular epithelial cells can phenotypically improve in vitro tubuloid maturation, thereby enhancing their potential as functional units in regenerative or renal replacement therapies. Graphical Abstract

Polarized HLA Class I Expression on Renal Tubules Hinders the Detection of Donor-Specific Urinary Extracellular Vesicles

“…Renal tubular epithelial cells possess a highly polarized membrane structure, with the apical membrane in direct contact with pro-urine, facilitating the excretion of EVs into urine. 25 , 53 , 54 The Apical membrane is more active in EV excretion than the basolateral membrane, with distinctive EV proteomics and miRNA profiles. Moreover, a dense monolayer of renal tubules establishes high impermeability, allowing less than 1% of EVs to pass through over 72 hours.…”

Extracellular vesicles in kidney development and pediatric kidney diseases

“…This study underlines the important role of EV communication during nephrogenesis, and additional studies will be of interest to fully understand the EV mechanisms of action during kidney development. A recent study found that EVs from engineered kidney tubular epithelial cells improve tubuloid maturation [ 14 ]. Indeed, EVs from proximal tubule epithelial cells overexpressing organic anion transporter, a membrane transporter involved in the excretion of waste, enhanced tubuloid polarization, cilia structure formation and epithelial transport capacity.…”

“…Indeed, EVs from proximal tubule epithelial cells overexpressing organic anion transporter, a membrane transporter involved in the excretion of waste, enhanced tubuloid polarization, cilia structure formation and epithelial transport capacity. Some authors also suggest that EVs can be a major tool for developing bioartificial kidneys by promoting dense cilia structures and organoid differentiation and maturation [ 14 ].…”

Extracellular Vesicles in Kidney Diseases: Moving Forward

“…110,111 Similarly, EVs isolated from engineered proximal tubule cells were shown to improve the functional maturation of “tubuloids” (organoids showing a predominant tubular phenotype) including enhanced transport capacity of organic anion transporter 1. 112 This raises the possibility that EVs mediate proximal-to-distal cross-talk to modify transport function (see Figure 5). 113 If confirmed in vivo , this would represent a novel layer of regulation in addition to other signaling systems.…”