Although it is known that tumor necrosis factor-related apoptosis-inducing ligand (TNFSF10/TRAIL) induces autophagy, the mechanism by which autophagy is activated by TNFSF10 is still elusive. In th...

Tumour‑associated macrophages (TAMs) compose a major component of the tumour microenvironment and form in this microenvironment prior to cancer metastasis. However, the detailed mechanisms of TAM remodelling in the context of bladder cancer have not been clearly defined. The present study collected exosomes from the conditioned medium of human bladder T24 cancer cells. The effects of macrophages treated with exosomes derived from T24 cells on bladder cancer cell migration and invasion were analysed by Transwell assays. The expression levels of endogenous and exosomal microRNA‑21 (miR‑21) were examined by reverse transcription‑quantitative PCR, while the expression level of the target protein was analysed by western blot analysis. Luciferase reporter plasmids and mutants were used to confirm direct targeting. The effects of miR‑21 on bladder cancer cell migration and invasion were analysed by Transwell and Matrigel assays following miR‑21 transfection. It was identified that exosomes derived from bladder cancer cells polarized THP‑1 cell‑derived macrophages into the M2 phenotype, and TAM‑mediated pro‑migratory and pro‑invasive activity was determined. Moreover, it was found that miR‑21 was highly expressed in exosomes derived from bladder cancer cells as well as in macrophages treated with exosomes. In addition, macrophages transfected with miR‑21 exhibited M2 polarization and promoted T24 cell migratory and invasive ability. Mechanistically, exosomal miR‑21 derived from bladder cancer cells inhibited phosphatase and tensin homolog activation of the PI3K/AKT signalling pathway in macrophages and enhanced STAT3 expression to promote M2 phenotypic polarization. The present results suggest that exosomal miR‑21 can promote cancer progression by polarizing TAMs.

Bone marrow–derived mesenchymal stem cells (BMSCs) have been recently reported to play a variety of vital roles in organ and tissue damage repair, mainly via potent paracrine activity, including secreting extracellular vesicles, such as exosomes, that serve as mediators facilitating intercellular communication and reprogramming recipient cells by delivering their contents to target cells. However, the underlying mechanisms are diverse and complex, and the influencing characteristics have rarely been studied. Accordingly, we designed this study to explore the time dependence of the effects of exosomes derived from BMSCs (BMexos) on renal ischemia‐reperfusion (I/R) injury and the underlying mechanisms associated with the reperfusion time. Impressively, our study is the first to find that BMexos protected against renal I/R injury in vitro and in vivo at the very early reperfusion stages, especially 4–8 h after reperfusion in vitro and 8–16 h after reperfusion in vivo . Interestingly, we simultaneously found that endoplasmic reticulum (ER) stress was significantly suppressed following the administration of BMexos in vitro and in vivo with a similar time dependence. Additionally, we discovered that miR‐199a‐5p, which was abundant in the BMSCs, was transferred into renal tubular epithelial cells (NRK‐52E) in a time‐dependent manner and significantly inhibited I/R‐induced ER stress by targeting binding immunoglobulin protein (BIP). Cocultivation with miR‐199a‐5p‐overexpressing BMSCs amplified the suppression of ER stress and further protected against I/R injury. However, coculture with miR‐199a‐5p‐knockdown BMSCs obviously increased ER stress and reversed the BMexos‐induced protection, and silencing BIP by small interfering RNA–1098 in NRK‐52E inhibited these effects. This study provides evidence that administering BMexos at the very early reperfusion stages significantly protects against renal I/R injury, and ER stress is closely linked to this protection. These results suggest a novel therapeutic strategy during the very early reperfusion stages of renal I/R injury.—Wang, C., Zhu, G., He, W., Yin, H., Lin, F., Gou, X., Li, X. BMSCs protect against renal ischemia‐reperfusion injury by secreting exosomes loaded with miR‐199a‐5p that target BIP to inhibit endoplasmic reticulum stress at the very early reperfusion stages. FASEB J. 33, 5440–5456 (2019). www.fasebj.org

Bladder cancer is a leading cause of morbidity and mortality worldwide. Currently, immunotherapy has become a worthwhile therapy for bladder cancer. Tumor mutation burden (TMB) has been regarded as the most prevalent biomarker to predict immunotherapy. Bladder cancer is reported to have the third highest mutation rate. However, whether these gene mutations are related to TMB and immune response remain unknown. In this study, we downloaded somatic mutation data of bladder cancer from The Cancer Genome Atlas (TCGA) and International Cancer Genome Consortium (ICGC) datasets, and found 11 frequently mutated genes were covered by both two cohorts including FGFR3, TTN, XIRP2, CREBBP, PIK3CA, TP53, MUC16, EP300 (E1A binding protein P300), ARID1A, ERBB2, and KDM6A. Among them, EP300 mutation was associated with higher TMB and indicated a favorable clinical prognosis. Furthermore, based on Gene set enrichment analysis (GSEA) and CIBERSORT algorithm, we observed that EP300 mutation upregulated signaling pathways involved in immune system and enhanced antitumor immune response. In conclusion, EP300 is frequently mutated in bladder cancer, and its mutation is associated with increased TMB and promotes antitumor immunity, which may serve as a biomarker to predict immune response.