Mesenchymal Stem Cells Deliver Exogenous MicroRNA-let7c via Exosomes to Attenuate Renal Fibrosis

Abstract

The advancement of microRNA (miRNA) therapies has been hampered by difficulties in delivering miRNA to the injured kidney in a robust and sustainable manner. Using bioluminescence imaging in mice with unilateral ureteral obstruction (UUO), we report that mesenchymal stem cells (MSCs), engineered to overexpress miRNA-let7c (miR-let7c-MSCs), selectively homed to damaged kidneys and upregulated miR-let7c gene expression, compared with nontargeting control (NTC)-MSCs. miR-let7c-MSC therapy attenuated kidney injury and significantly downregulated collagen IVα1, metalloproteinase-9, transforming growth factor (TGF)-β1, and TGF-β type 1 receptor (TGF-βR1) in UUO kidneys, compared with controls. In vitro analysis confirmed that the transfer of miR-let7c from miR-let7c-MSCs occurred via secreted exosomal uptake, visualized in NRK52E cells using cyc3-labeled pre-miRNA-transfected MSCs with/without the exosomal inhibitor, GW4869. The upregulated expression of fibrotic genes in NRK52E cells induced by TGF-β1 was repressed following the addition of isolated exosomes or indirect coculture of miR-let7c-MSCs, compared with NTC-MSCs. Furthermore, the cotransfection of NRK52E cells using the 3'UTR of TGF-βR1 confirmed that miR-let7c attenuates TGF-β1-driven TGF-βR1 gene expression. Taken together, the effective antifibrotic function of engineered MSCs is able to selectively transfer miR-let7c to damaged kidney cells and will pave the way for the use of MSCs for therapeutic delivery of miRNA targeted at kidney disease.

Exosome and Microvesicle-Enriched Fractions Isolated from Mesenchymal Stem Cells by Gradient Separation Showed Different Molecular Signatures and Functions on Renal Tubular Epithelial Cells

“…The activity of EVs has been at least in part ascribed to their miRNA content [42–45]. A subset of miRNA families, was specific signature of the biologically active CF2 medium-density fraction.…”

Prospective application of stem cells to prevent post‐operative skeletal fibrosis

“…Kidney fibrosis commonly appearing interstitially is considered a feature of chronic kidney disease. In a recent study, stem cells were tested for the effect on kidney fibrosis models, including Col4α3 –/– and Col4α5 −/− , unilateral ureteral obstruction (UUO), remnant kidney, renal artery stenosis, transplantation, unilateral ischemia‐reperfusion (IR) injury and nephrectomy IR cyclosporine . Evidence indicates that stem cells could reduce renal fibrosis through some potential mechanisms, including inhibition of the renin‐angiotensin system, suppression of the inflammatory response, activation of the paracrine system and regeneration of podocytes .…”

“…In addition to the above mentioned mechanisms, others include the p38/MAPK pathway, regulation of miR‐let7c and the ER stress pathway . In particular, ER stress has been proven to be linked to post‐operative skeletal fibrosis .…”

Mesenchymal stromal cells prevent bleomycin‐induced lung and skin fibrosis in aged mice and restore wound healing

“…MSCs have been shown to exert anti‐inflammatory, anti‐oxidant, and immunomodulatory effects, as well as an ability to modulate pro‐fibrotic factors (Eming, Martin, & Tomic‐Canic, ; Toonkel, Hare, Matthay, & Glassberg, ; Usunier et al, ). MSCs have been investigated in pre‐clinical and clinical studies for diseases in various organs including the heart (Chen et al, ), lung (Glassberg et al, ), kidney (Wang et al, ), liver (Haldar, Henderson, Hirschfield, & Newsome, ), and skin (Ojeh, Pastar, Tomic‐Canic, & Stojadinovic, ; Otero‐Vinas & Falanga, ). Benefits of MSCs in various organs are thought to stem from their ability to adapt to the local environment and regulate its secretome (Usunier et al, ).…”