In this study, we constructed engineered exosomes carrying the long non-coding RNA (lncRNA) SVIL-AS1 (SVIL-AS1 Exos), and explored its role and mechanism in lung cancer. After the construction of SVIL-AS1 Exos, their physicochemical characteristics were identified. Then, their function and effect in three different cell lines, A549, HeLa, and HepG2, were detected using western blot, the quantitative reverse transcriptase polymerase chain reaction, flow cytometry, 5-ethynyl-2\'-deoxyuridine, and Cell Counting Kit-8 experiments. Finally, a mouse xenograft model was constructed to analyze tumor growth and explore the in vivo utility of SVIL-AS1 Exos using hematoxylin and eosin staining, immunohistochemistry, and the TdT-mediated dUTP nick end labeling assay. The results demonstrated that SVIL-AS1 Exos preferentially targeted A549 lung cancer cells over HeLa and HepG2 cells. SVIL-AS1 Exos promoted apoptosis and inhibited A549 cell proliferation by elevating expression of the lncRNA, SVIL-AS1. In vivo, SVIL-AS1 Exos effectively inhibited the growth of lung cancer A549 cells. Furthermore, SVIL-AS1 Exos suppressed the expression of miR-21-5p and upregulated the expression of caspase-9, indicating that SVIL-AS1 may regulate the development of lung cancer through the miR-21-5p/caspase-9 pathway. In conclusion, the engineered SVIL-AS1 Exos targeted lung cancer cells to inhibit the expression of miR-21-5p, upregulate the expression of caspase-9, and inhibit the development of lung cancer.

BACKGROUND: MiR-21-5p is a highly expressed microRNA that plays an important role in various cancer-promoting processes, including anchorage-independent growth, invasion, migration metastasis, and drug resistance in lung cancer. Studies indicate that miR-21-5p may contribute to these processes by promoting epithelial-mesenchymal transition (EMT). Ras homolog gene family member B (RhoB), a gene downregulated by miR-21-5p, has also been linked to EMT in lung cancer. However, the role of the miR-21-5p/RhoB axis in EMT regulation in lung adenocarcinoma remains unclear. In this study, we aimed to investigate the regulatory role of the miR-21-5p/RhoB axis in EMT and related in vitro functional characteristics such as migration, invasion, cisplatin resistance, and the formation of tumor spheroids.
RESULTS: A549 cells were transfected with the miR-21-5p inhibitor, RhoB siRNA, and their corresponding negative controls. Wound healing, transwell invasion, Methyl thiazole tetrazolium (MTT), and sphere formation assays were also performed to evaluate the migration, invasion, cisplatin resistance, and anchorage-independent growth of A549 cells. RT-qPCR was used to determine the mRNA expression levels of EMT markers. MiR-21-5p knockdown inhibited migration, invasion, cisplatin resistance, and sphere formation while upregulating E-cadherin and downregulating Slug. Furthermore, RhoB silencing restored EMT and related in vitro functional characteristics in A549 cells.
CONCLUSIONS: Knockdown of miR-21-5p inhibits EMT and related in vitro functional characteristics by upregulating RhoB, suggesting that miR-21-5p may promote EMT through downregulation of RhoB.

Bladder cancer (BC) is one of the most prevalent malignant tumors worldwide, and the incidence is especially higher in males. Extensive evidence has demonstrated the pivotal role of circular RNAs (circRNAs) in BC progression. However, the exact regulatory mechanism of circRNAs in BC remains incompletely elucidated and warrants further exploration. This study screened a novel circRNA-circPGM5 from thousands of circRNAs by high-throughput sequencing. We found that circPGM5, originating from the PGM5 gene, was significantly lower expressed in BC tissues. Quantitative real-time PCR (qRT-PCR) verified that circPGM5 showed relatively low expression in 50 pairs of BC tissues and EJ and T24 cells. Notably, circPGM5 expression was correlated with stage, grade, and lymphatic metastasis of BC. Through RNA-FISH assay, we confirmed that circPGM5 predominantly localized in the cytoplasm. Functionally, overexpression of circPGM5 inhibited the proliferation, migration, and invasion of BC cells in vitro. Remarkably, circPGM5 demonstrated markedly significant tumor growth and metastasis suppression in vivo. Mechanistically, we discovered that circPGM5 upregulated the mitogen-activated protein kinase 10 (MAPK10) expression by influencing the oncogenic miR-21-5p activity through miR-21-5p absorption. This modulation of MAPK10 impacted the phosphorylation of the tumor suppressor Foxo3a in BC. In conclusion, our findings uncovered the tumor-suppressing role of circPGM5 in BC via the miR-21-5p/MAPK10/Foxo3a axis.

OBJECTIVE: Exosome-based therapies are gaining increasing attention, with growing evidence suggesting a link between alterations in mesentery adipose tissue (MAT) and intestinal disease in Crohn\'s disease (CD). However, the specific mechanism by which mesenchymal stem cells (MSCs)-Exos may alleviate colitis through targeting MAT remains not fully understood.
METHODS: Human umbilical cord MSCs (HucMSCs) were cultured to isolate the corresponding exosomes (HucMSCs-Exos), which were confirmed by their morphology, size distribution, and expression of markers. In vivo, 2,4,6-trinitrobenzenesulfonic acid solution (TNBS) and dextran sodium sulfate (DSS) -induced mouse colitis models were used to detect the therapeutic effects of HucMSCs-Exos. ELISA, qRT-PCR, western blotting, and immunofluorescence determined the expression of key molecules. Luciferase reporter assay was used to confirm the relationship between miR-21-5p and SPRY2.
RESULTS: Exosomes treatment through mesenteric injection demonstrated therapeutic effects on mesenteric inflammation and colitis. These therapeutic benefits were contingent on macrophages, significantly facilitating the M2 polarization of mesenteric macrophages. The expression data from GSE159814 and GSE211008 revealed that exosomal miR-21-5p was enriched in HucMSCs-Exos and could be delivered to macrophages. Additionally, the results indicated that miR-21-5p could directly target the 3\'UTR of SPRY2 and activate the phosphorylation of ERK to modify macrophage phenotypes. Mechanistically, exosomal miR-21-5p derived from HucMSCs could promote macrophage M2 polarization via the SPRY2/ERK axis.
CONCLUSIONS: Mesenteric injection of HucMSCs-Exos significantly alleviates mesenteric inflammation and colitis by promoting mesenteric macrophage M2 polarization, making it a promising approach to treat colitis and suggesting therapeutic potential role of exosomal miR-21-5p in CD.

The toxicity of silica nanoparticles (SiNPs) to lung is known. We previously demonstrated that exposure to SiNPs promoted pulmonary impairments, but the precise pathogenesis remains elucidated. Ferroptosis has now been identified as a unique form of oxidative cell death, but whether it participated in SiNPs-induced lung injury remains unclear. In this work, we established a rat model with sub-chronic inhalation exposure of SiNPs via intratracheal instillation, and conducted histopathological examination, iron detection, and ferroptosis-related lipid peroxidation and protein assays. Moreover, we evaluated the effect of SiNPs on epithelial ferroptosis, possible mechanisms using in vitro-cultured human bronchial epithelial cells (16HBE), and also assessed the ensuing impact on fibroblast activation for fibrogenesis. Consequently, fibrotic lesions occurred in the rat lungs, concomitantly by enhanced lipid peroxidation, iron overload, and ferroptosis. Consistently, the in vitro data showed SiNPs triggered oxidative stress and caused the accumulation of lipid peroxides, resulting in ferroptosis. Importantly, the mechanistic investigation revealed miR-21-5p as a key player in the epithelial ferroptotic process induced by SiNPs via targeting GCLM for GSH depletion. Of note, ferrostatin-1 could greatly suppress ferroptosis and alleviate epithelial injury and ensuing fibroblast activation by SiNPs. In conclusion, our findings first revealed SiNPs triggered epithelial ferroptosis through miR-21-5p/GCLM signaling and thereby promoted fibroblast activation for fibrotic lesions, and highlighted the therapeutic potential of inhibiting ferroptosis against lung impairments upon SiNPs exposure.

BACKGROUND: Endothelial cell (EC)-driven intraneural revascularization (INRV) and Schwann cells-derived exosomes (SCs-Exos) both play crucial roles in peripheral nerve injury (PNI). However, the interplay between them remains unclear. We aimed to elucidate the effects and underlying mechanisms of SCs-Exos on INRV following PNI.
RESULTS: We found that GW4869 inhibited INRV, as well as that normoxic SCs-Exos (N-SCs-Exos) exhibited significant pro-INRV effects in vivo and in vitro that were potentiated by hypoxic SCs-Exos (H-SCs-Exos). Upregulation of glycolysis emerged as a pivotal factor for INRV after PNI, as evidenced by the observation that 3PO administration, a glycolytic inhibitor, inhibited the INRV process in vivo and in vitro. H-SCs-Exos more significantly enhanced extracellular acidification rate/oxygen consumption rate ratio, lactate production, and glycolytic gene expression while simultaneously suppressing acetyl-CoA production and pyruvate dehydrogenase E1 subunit alpha (PDH-E1α) expression than N-SCs-Exos both in vivo and in vitro. Furthermore, we determined that H-SCs-Exos were more enriched with miR-21-5p than N-SCs-Exos. Knockdown of miR-21-5p significantly attenuated the pro-glycolysis and pro-INRV effects of H-SCs-Exos. Mechanistically, miR-21-5p orchestrated EC metabolism in favor of glycolysis by targeting von Hippel-Lindau/hypoxia-inducible factor-1α and PDH-E1α, thereby enhancing hypoxia-inducible factor-1α-mediated glycolysis and inhibiting PDH-E1α-mediated oxidative phosphorylation.
CONCLUSIONS: This study unveiled a novel intrinsic mechanism of pro-INRV after PNI, providing a promising therapeutic target for post-injury peripheral nerve regeneration and repair.

BACKGROUND: Cerebral ischemia (CI) induces a profound neuroinflammatory response, but the underlying molecular mechanism remains unclear. Exosomes from adipose-derived stem cells (ADSC-exos) have been found to play a crucial role in cell communication by transferring molecules including microRNAs (miRNAs), which have been shown to modulate the inflammatory response after CI and are viable molecular targets for altering brain function. The current study aimed to explore the contribution of ADSC-exosomal miR-21-5p to the neuroinflammation after CI.
METHODS: The differentially expressed miR-21-5p in CI was screened based on literature search. The target mRNAs of miR-21-5p were predicted using online databases and verified by luciferase reporter assay. Then, BV2 cells were treated with hemin to simulate the inflammatory response after CI, and its animal model was induced using the MCAO method. Ischemia was evaluated in rats using 2, 3, 5-triphenyl tetrazolium chloride (TTC) staining. ADSCs-exos were further isolated and identified by western blot analysis and transmission electron microscope.
RESULTS: MiR-21-5p was significantly down-regulated in CI and alleviated neuropathic damage after CI by the PIK3R1/PI3K/AKT signaling axis. And miR-21-5p derived from ADSCs-exos alleviated neuroinflammation after CI via promoting microglial M2 polarization.
CONCLUSIONS: We demonstrated that ADSC-exosomal miR-21-5p mitigated post-CI inflammatory response through the PIK3R1/PI3K/AKT signaling axis and could offer neuroprotection after CI through promoting polarization of M2 microglia.

Sepsis is a systemic inflammatory response syndrome resulting from the invasion of the human body by bacteria and other pathogenic microorganisms. One of its most prevalent complications is acute lung injury, which places a significant medical burden on numerous countries and regions due to its high morbidity and mortality rates. MicroRNA (miRNA) plays a critical role in the body\'s inflammatory response and immune regulation. Recent studies have focused on miR-21-5p in the context of acute lung injury, but its role appears to vary in different models of this condition. In the LPS-induced acute injury model of A549 cells, there is differential expression, but the specific mechanism remains unclear. Therefore, our aim is to investigate the changes in the expression of miR-21-5p and SLC16A10 in a type II alveolar epithelial cell injury model induced by LPS and explore the therapeutic effects of their targeted regulation. A549 cells were directly stimulated with 10 µg/ml of LPS to construct a model of LPS-induced cell injury. Cells were collected at different time points and the expression of interleukin 1 beta (IL-1β), tumor necrosis factor-α (TNF-α) and miR-21-5p were measured by RT-qPCR and western blot. Then miR-21-5p mimic transfection was used to up-regulate the expression of miR-21-5p in A549 cells and the expression of IL-1β and TNF-α in each group of cells was measured by RT-qPCR and western blot. The miRDB, TargetScan, miRWalk, Starbase, Tarbase and miR Tarbase databases were used to predict the miR-21-5p target genes and simultaneously, the DisGeNet database was used to search the sepsis-related gene groups. The intersection of the two groups was taken as the core gene. Luciferase reporter assay further verified SLC16A10 as the core gene with miR-21-5p. The expression of miR-21-5p and SLC16A10 were regulated by transfection or inhibitors in A549 cells with or without LPS stimulation. And then the expression of IL-1β and TNF-α in A549 cells was tested by RT-qPCR and western blot in different groups, clarifying the role of miR-21-5p-SLC16A10 axis in LPS-induced inflammatory injury in A549 cells. (1) IL-1β and TNF-α mRNA and protein expression significantly increased at 6, 12, and 24 h after LPS stimulation as well as the miR-21-5p expression compared with the control group (P < 0.05). (2) After overexpression of miR-21-5p in A549 cells, the expression of IL-1β and TNF-α was significantly reduced after LPS stimulation, suggesting that miR-21-5p has a protection against LPS-induced injury. (3) The core gene set, comprising 51 target genes of miR-21-5p intersecting with the 1448 sepsis-related genes, was identified. This set includes SLC16A10, TNPO1, STAT3, PIK3R1, and FASLG. Following a literature review, SLC16A10 was selected as the ultimate target gene. Dual luciferase assay results confirmed that SLC16A10 is indeed a target gene of miR-21-5p. (4) Knocking down SLC16A10 expression by siRNA significantly reduced the expression of IL-1β and TNF-α in A549 cells after LPS treatment (P < 0.05). (5) miR-21-5p inhibitor increased the expression levels of IL-1β and TNF-α in A549 cells after LPS stimulation (P < 0.05). In comparison to cells solely transfected with miR-21-5p inhibitor, co-transfection of miR-21-5p inhibitor and si-SLC6A10 significantly reduced the expression of IL-1β and TNF-α (P < 0.05). MiR-21-5p plays a protective role in LPS-induced acute inflammatory injury of A549 cells. By targeting SLC16A10, it effectively mitigates the inflammatory response in A549 cells induced by LPS. Furthermore, SLC16A10 holds promise as a potential target for the treatment of acute lung injury.

The potential function and mechanism of circRNAs in regulating malignant performances of Osteosarcoma (OS) cells have not been well investigated. The expression level of CircLMO7, miR-21-5p and ARHGAP24 were detected by RT-qPCR. The relationship between miR-21-5p and circ-LMO7, as well as between miR-21-5p and ARHGAP24, was predicted and examined through bioinformatics analysis and luciferase reporter gene experiments. Moreover, OS cell growth, invasion, migration, and apoptosis were detected using the cell counting kit-8 (CCK-8), transwell and flow cytometry assays, respectively. ARHGAP24 protein level was measured using western blotting. In present study, we choose to investigate the role and mechanism of circ-LOM7 on OS cell proliferation, migration and invasion. circ-LOM7 was found to be down-regulated in OS tissues and cell lines. Enforced expression of circ-LOM7 suppressed the growth, invasion, and migration of OS cells. In contrast, decreasing circ-LMO7 expression had opposite effects. Furthermore, miR-21-5p was predicted to be sponged by circ-LMO7, and had an opposite role of circ-LMO7 in OS. Moreover, ARHGAP24 served as miR-21-5p\'s downstream target. Mechanistically, circ-LMO7 was packed in exosomes and acted as a cancer-suppresser on OS by sponging miR-21-5p and upregulating the expression of ARHGAP24. The exosomal circ-LMO7 expression was significantly decreased in OS cell exosomes, and co-culture experiments showed that exosomal circ-LMO7 suppressed the proliferation ability of OS cells. Circ-LMO7 exerts as a tumor suppressor in OS, and the circ-LMO7/miR-21-5P/ARHGAP24 axis is involved in OS progression.

Developing effective methods for alveolar bone defect regeneration is a significant challenge in orthopedics. Exosomes from human umbilical cord mesenchymal stem cells (HUMSC-Exos) have shown potential in bone repair but face limitations due to undefined application methods and mechanisms. To address this, HUMSC-Exos were encapsulated in polyvinyl alcohol (PVA) hydrogel (Exo@PVA) to create a novel material for alveolar bone repair. This combination enhanced the osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) and human umbilical vein endothelial cells (HUVECs) more effectively than Exos alone. Additionally, Exo@PVA significantly improved alveolar bone regeneration and defect repair in rats. The microRNA-21-5p (miR-21-5p) in Exo@PVA, identified through the GEO database and analyzed via in silico methods, played a crucial role. miR-21-5p promoted BMSC osteogenic differentiation by inhibiting WWP1-mediated KLF5 ubiquitination and enhanced HUVEC angiogenesis by targeting ATP2B4. These findings underscore the potential of an Exo-based approach with PVA hydrogel scaffolds for bone defect repair, operating through the miR-21-5p/WWP1/ATP2B4 signaling axis.