Tumour-Derived, Extracellular Microvesicles in the Treatment of Acute Renal Failure: An Experimental Study

Abstract

Background/Objectives: This investigation compared the therapeutic efficacy of extracellular microvesicles (MVs) derived from murine L929 sarcoma cells and murine mesenchymal stem cells (MSCs). Methods: A mouse model of acute kidney injury (AKI) was used. Results: Both MVs from L929 cells (L929-MVs) and MSCs (MSC-MVs), unlike those obtained from murine peripheral blood mononuclear cells (PBMCs), enhanced survival rates in AKI mice and significantly improved kidney function. This was indicated by decreased levels of urine albumin and serum creatinine. Furthermore, treatment with L929-MVs and MSC-MVs elevated the proportions of CD4+CD25+FOXP3+ regulatory T cells while reducing the presence of pro-inflammatory CD4+CD44+ T cells in the spleens of AKI mice. Conclusions: the results highlight the potential of tumour-derived MVs to facilitate organ repair and exert cytoprotective immunomodulatory effects.

Keywords: acute kidney injury; mesenchymal stem cell; microvesicles; regeneration; tumour.

Figure 1

Analysis of exovesicle size distribution by flow cytometry. (A) Negative control without exovesicle-containing standard annexin V-FITC particles; (B) exovesicles derived from MSCs; (C) exovesicles derived from the L929 tumour cell line. Events above the threshold levels in the FITC channel were gated and analysed on SSC/FCS histograms; 10 nm—standard particles of 10 nm in diameter for gating microvesicles according to size; P5—area used for analysis and enumeration of microvesicles sized between 100 nm and 1 μm; P3—area used for analysis and enumeration of exovesicles sized 3 μm for normalizing exovesicle enumeration.

Figure 2

Albumin concentrations in the urine of acute kidney injury mice. Albumin levels were measured in untreated control acute kidney injury mice as well as in acute kidney injury mice treated with L929 microvesicles, mesenchymal stem cell microvesicles, or peripheral blood mononuclear cell-derived microvesicles. n = 6 ** p < 0.05 compared to control acute kidney injury mice.

Figure 3

Creatinine concentrations in the sera of acute kidney injury mice. Serum creatinine levels were measured in untreated (control) acute kidney injury mice and in acute kidney injury mice treated with L929 cell-derived microvesicles, mesenchymal stem cell-derived microvesicles, or peripheral blood mononuclear cell-derived microvesicles. n = 6 ** p < 0.05 compared to intact or control acute kidney injury mice.

Figure 4

(A–C) Morphological structure of the damaged kidneys in acute kidney injury mice. (A) acute kidney injury mice, (B) acute kidney injury mice treated with mesenchymal stem cell-derived microvesicles, (C) acute kidney injury mice treated with L929 cell-derived microvesicles; (a) kidney glomeruli, proximal and distal tubules, (b) collecting ducts and Henle’s loops at the junction between the cortex and medulla of the kidney.

Figure 5

Relative proportion of cytoprotective regulatory T cells in the spleens of acute kidney injury mice. The percentage of CD4+CD25+FOXP3+ T cells was determined in the spleens of untreated control acute kidney injury mice and acute kidney injury mice treated with mesenchymal stem cell-derived microvesicles or L929 cell-derived microvesicles. Measurements were taken on day 12 following acute kidney injury induction. n = 6, *** p < 0.001, ** p < 0.05 compared to control acute kidney injury mice.

Figure 6

Relative proportion of cytodestructive pro-inflammatory T cells in the spleens of acute kidney injury mice. The percentage of CD4+CD44+CD62L+ T cells was assessed in the spleens of untreated control acute kidney injury mice and acute kidney injury mice treated with mesenchymal stem cell-derived microvesicles or L929 cell-derived MVs. Measurements were taken on day 12 after AKI induction. n = 6, *** p < 0.001, ** p < 0.05 compared to control or acute kidney injury.