Exosomes derived from bone marrow mesenchymal stem cells inhibit human aortic vascular smooth muscle cells calcification via the miR-15a/15b/16/NFATc3/OCN axis.

Cardiovascular events among patients with chronic kidney disease (CKD) are associated with vascular calcification (VC). Nevertheless, the process of vascular calcification is complicated. A mechanism of VC is cellular osteogenic transdifferentiation. The mechanism through which bone marrow mesenchymal stem cell-derived exosomes (BMSC-Exo) relieve VC is unknown. For the purpose of this study, we used human aortic vascular smooth muscle cells (HA-VSMCs) stimulated by high phosphate to investigate how BMSC-Exo works. Cell calcification was detected by Alizarin red S staining, AKP activity analysis, and the Ca2+ concentration test. The dual-luciferase reporter gene assays were utilized to confirm the targeting link between miR-15a-5p, miR-15b-5p, and miR-16-5p (miR-15a/15b/16) and nuclear factors of activated T cells 3 (NFATc3). The expression of osteogenic transdifferentiation biomarkers was detected using Western blot and RT-qPCR. Based on our findings, miR-15a/15b/16 plays a crucial role in BMSC-Exo's inhibitory effects on calcification and osteogenic transdifferentiation. We then confirmed that miR-15a/15b/16 specifically target the 3'UTR of NFATc3 mRNA and that three miRNAs are more effective than one miRNA. Moreover, we found that down-regulation of NFATc3 could inhibit osteocalcin (OCN) expression, thereby inhibiting the osteogenic transdifferentiation and calcification of HA-VSMCs. This study found that BMSC-Exo plays a role in calcification inhibition by transferring miR-15a/15b/16 and inhibiting their common target gene NFATc3, which down-regulates OCN expression and thus inhibits HA-VSMC osteogenic transdifferentiation. This study identifies a novel target for therapeutic therapy of CKD-VC.

Knockdown of NLRP3 alleviates high glucose or TGFB1-induced EMT in human renal tubular cells

Tubular injury is one of the crucial determinants of progressive renal failure in diabetic nephropathy (DN), while epithelial-to-mesenchymal transition (EMT) of tubular cells contributes to the accumulation of matrix protein in the diabetic kidney. Activation of the nucleotide binding and oligomerization domain-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome leads to the maturation of interleukin (IL)-1B and is involved in the pathogenic mechanisms of diabetes. In this study, we explored the role of NLRP3 inflammasome on high glucose (HG) or transforming growth factor-B1 (TGFB1)-induced EMT in HK-2 cells. We evaluated EMT through the expression of α-smooth muscle actin (α-SMA) and E-cadherin as well as the induction of a myofibroblastic phenotype. Reactive oxygen species (ROS) was observed using the confocal microscopy. HG was shown to induce EMT at 48 h, which was blocked by NLRP3 silencing or antioxidant N-acetyl-L-cysteine (NAC). We found that NLRP3 interference could inhibit HG-induced ROS. Knockdown of NLRP3 could prevent HG-induced EMT by inhibiting the phosphorylation of SMAD3, P38 MAPK and ERK1/2. In addition, P38 MAPK and ERK1/2 might be involved in HG-induced NLRP3 inflammasome activation. Besides, TGFB1 induced the activation of NLRP3 inflammasome and the generation of ROS, which were blocked by NLRP3 interference or NAC. Tubular cells exposed to TGFB1 also underwent EMT, and this could be inhibited by NLRP3 shRNA or NAC. These results indicated that knockdown of NLRP3 antagonized HG-induced EMT by inhibiting ROS production, phosphorylation of SMAD3, P38MAPK and ERK1/2, highlighting NLRP3 as a potential therapy target for diabetic nephropathy.