Wenli Zhou

Excessive accumulation of reactive oxygen species (ROS) in the brain and the resulting oxidative stress are core drivers of neurodegenerative processes. Human dental pulp stem cells (DPSCs) secrete small extracellular vesicles (sEVs) abundant in functional microRNAs, which possess prominent regenerative capacity. The present study investigated the neuroprotective effects of DPSC-derived sEVs (DPSC-sEVs) against oxidative injury in SH-SY5Y neuronal cells and elucidated the underlying molecular mechanisms. DPSC identity was confirmed via flow cytometric immunophenotyping and multipotent differentiation assays. sEVs were isolated from DPSC-conditioned medium and characterized by transmission electron microscopy, nanoparticle tracking analysis and detection of canonical exosomal markers (CD63, CD81, and TSG101). An in vitro model of neuronal oxidative stress was established using hydrogen peroxide (H₂O₂). Cell viability, apoptosis, intracellular ROS levels, and lactate dehydrogenase (LDH) release, as well as the levels/activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and malondialdehyde (MDA), were assessed to evaluate the protective effects of sEVs. Candidate miRNAs in sEVs were screened by quantitative real-time PCR (qPCR). Direct binding of miR-100-5p to the 3′ untranslated region (3′UTR) of mammalian target of rapamycin (mTOR) was verified via dual-luciferase reporter assay. Autophagic activity was evaluated by immunoblotting and immunofluorescence staining of LC3B/p62. Pretreatment with DPSC-sEVs significantly ameliorated H₂O₂-induced neuronal oxidative damage and apoptosis. Mechanistically, sEV miR-100-5p conferred neuroprotective and antioxidant properties by inhibiting mTOR signaling and activating autophagy in vitro. Blockade of miR-100-5p or pharmacological inhibition of autophagy by 3-methyladenine (3-MA) largely abolished these protective effects. In conclusion, DPSC-sEVs attenuate neuronal oxidative stress by reversing mTOR-mediated suppression of autophagy, and this protective effect is dependent on the function of miR-100-5p in SH-SY5Y cells. The miR-100-5p/mTOR/autophagy axis mediates the neuroprotective effects of DPSC-sEVs, representing a promising therapeutic candidate for oxidative stress-associated neurodegenerative diseases that merits further in vivo validation.

Tumor-associated macrophages (TAMs) are inflammatory cells that are important components of the tumor microenvironment. TAMs are functionally heterogeneous and divided into two main subpopulations with distinct and opposite functions: M1 and M2 macrophages. The secretory function of TAMs is essential for combating infections, regulating immune responses, and promoting tissue repair. Extracellular vesicles (EVs) are nanovesicles that are secreted by cells. They play a crucial role in mediating intercellular information transfer between cells. EVs can be secreted by almost all types of cells, and they contain proteins, microRNAs, mRNAs, and even long non-coding RNAs (lncRNAs) that have been retained from the parental cell through the process of biogenesis. EVs can influence the function and behavior of target cells by delivering their contents, thus reflecting, to some extent, the characteristics of their parental cells. Here, we provide an overview of the role of M1 macrophages and their EVs in cancer therapy by exploring the impact of M1 macrophage-derived EVs (M1-EVs) on tumors by transferring small microRNAs. Additionally, we discuss the potential of M1-EVs as drug carriers and the possibility of reprogramming M2 macrophages into M1 macrophages for disease treatment. We propose that M1-EVs play a crucial role in cancer therapy by transferring microRNAs and loading them with drugs. Reprogramming M2 macrophages into M1 macrophages holds great promise in the treatment of cancers.