Exosomal microRNA-342-5p secreted from adipose-derived mesenchymal stem cells mitigates acute kidney injury in sepsis mice by inhibiting TLR9

Abstract

Background Sepsis-related acute kidney injury (AKI) is an inflammatory disease associated with extremely high mortality and health burden. This study explored the possibility of exosomes secreted by adipose-derived mesenchymal stem cells (AMSCs) serving as a carrier for microRNA (miR)-342-5p to alleviate sepsis-related AKI and investigated the possible mechanism. Methods Serum was obtained from 30 patients with sepsis-associated AKI and 30 healthy volunteers for the measurement of miR-342-5p, blood urea nitrogen (BUN), and serum creatinine (SCr) levels. For in vitro experiments, AMSCs were transfected with LV-miR-342-5p or LV-miR-67 to acquire miR-342-5p-modified AMSCs and miR-67-modified AMSCs, from which the exosomes (AMSC-Exo-342 and AMSC-Exo-67) were isolated. The human renal proximal tubular epithelial cell line HK-2 was induced by lipopolysaccharide (LPS) to construct a cellular model of sepsis. The expression of Toll-like receptor 9 (TLR9) was also detected in AKI cells and mouse models. The interaction between miR-342-5p and TLR9 was predicted by dual luciferase reporter gene assay. Results Detection on clinical serum samples showed that BUN, SCr, and TLR9 were elevated and miR-342-5p level was suppressed in the serum of patients with sepsis-associated AKI. Transfection with LV-miR-342-5p reinforced miR-342-5p expression in AMSCs and AMSC-secreted exosomes. miR-342-5p negatively targeted TLR9. LPS treatment enhanced TLR9 expression, reduced miR-342-5p levels, suppressed autophagy, and increased inflammation in HK-2 cells, while the opposite trends were observed in LPS-induced HK-2 cells exposed to AMSC-Exo-342, Rapa, miR-342-5p mimic, or si-TLR9. Additionally, the effects of AMSC-Exo-342 on autophagy and inflammation in LPS-induced cells could be weakened by 3-MA or pcDNA3.1-TLR9 treatment. Injection of AMSC-Exo-342 enhanced autophagy, mitigated kidney injury, suppressed inflammation, and reduced BUN and SCr levels in sepsis-related AKI mouse models. Conclusion miR-342-5p transferred by exosomes from miR-342-5p-modified AMSCs ameliorated AKI by inhibiting TLR9 to accelerate autophagy. Graphical Abstract

3D Culture and Interferon-γ Priming Modulates Characteristics of Mesenchymal Stromal/Stem Cells by Modifying the Expression of Both Intracellular and Exosomal microRNAs

“…Xing et al found that EXOs derived from MSCs exhibited protective effects on endothelial cells in an in vitro model of atherosclerosis, and this protective effect was mediated by the action of miR-342-5p, which targeted PPP1R12B [ 45 ]. Moreover, Liu and colleagues nicely proved that exosomal miR-342-5p derived from MSCs had the ability to mitigate acute kidney injury by inhibiting TLR9 in a sepsis mouse model [ 46 ].…”

Regulation of immune responses to infection through interaction between stem cell-derived exosomes and toll-like receptors mediated by microRNA cargoes

“…Liu et al. conducted a study that showed miRNA-342-5p in exosomes secreted from AD-MSCs via TLR9 inhibition leads to the reduction of acute kidney damage (AKI) in LPS-induced sepsis mice ( Liu W. et al., 2023 ). This miRNA facilitates cellular autophagy by downregulating TLR9 expression, thereby leading to protection against sepsis-associated AKI.…”

“…This miRNA facilitates cellular autophagy by downregulating TLR9 expression, thereby leading to protection against sepsis-associated AKI. The results suggest that by influencing necrosis, inflammation, and apoptosis, selective activation of renal proximal tubule TLR9 may worsen ischemic AKI ( Liu W. et al., 2023 ). In addition, Zhang et al.…”

“…Based on this, several research has demonstrated that miRNAs and their interactions with TLRs have a significant impact on reducing AKI (Vaźquez-Carballo et al, 2021). Liu et al conducted a study that showed miRNA-342-5p in exosomes secreted from AD-MSCs via TLR9 inhibition leads to the reduction of acute kidney damage (AKI) in LPS-induced sepsis mice (Liu W. et al, 2023). This miRNA facilitates cellular autophagy by downregulating TLR9 expression, thereby leading to protection against sepsis-associated AKI.…”

The role of toll-like receptors in orchestrating osteogenic differentiation of mesenchymal stromal cells and osteoimmunology

“…Furthermore, the therapeutic efficacy of EVs in sepsis was partially diminished when transfected with miR-21a-5p inhibitors ( Niu et al, 2023 ). Liu et al reported that miR-342-5p secreted by h-AMSC-derived EVs negatively regulated TLR9 to induce autophagy, thereby attenuating inflammation induced by LPS and improving acute kidney injury (AKI) in a mouse model ( Liu et al, 2023 ). hplMSC-EVs could ameliorate LPS-induced inflammation in RAW264.7 cells by regulating TLR4-mediated NF-κB/MAPK and PI3K signaling pathways ( Hu et al, 2022 ).…”