Background: Stroke is a leading cause of adult disability that can severely compromise patients' quality of life, yet no effective medication currently exists to accelerate rehabilitation. A variety of circular RNA (circRNAs) molecules are known to function in ischemic brain injury. Lentivirus-based expression systems have been widely used in basic studies of circRNAs, but safety issues with such delivery systems have limited exploration of potential therapeutic roles for circRNAs. Methods: Circular RNA SCMH1 (circSCMH1) was screened from the plasma of acute ischemic stroke (AIS) patients using circRNA microarrays. Engineered RVG-circSCMH1-extracellular vesicles (RVG-circSCMH1-EVs) were generated to selectively deliver circSCMH1 to the brain. Nissl staining was used to examine infarct size. Behavioral tasks were performed to evaluate motor functions in both rodent and nonhuman primate ischemic stroke models. Golgi staining and immunostaining were used to examine neuroplasticity and glial activation. Proteomic assays and RNA-seq data combined with transcriptional profiling were used to identify downstream targets of circSCMH1. Results: CircSCMH1 levels were significantly decreased in plasma of AIS patients, offering significant power in predicting stroke outcomes. The decreased levels of circSCMH1 were further confirmed in the plasma and peri-infarct cortex of photothrombotic (PT) stroke mice. Beyond demonstrating proof-of-concept for an RNA drug delivery technology, we observed that circSCMH1 treatment improved functional recovery post stroke in both mice and monkeys, and discovered that circSCMH1 enhanced the neuronal plasticity and also inhibited glial activation and peripheral immune cell infiltration. Mechanistically, circSCMH1 binds to the transcription factor MeCP2, thereby releasing repression of MeCP2 target gene transcription. Conclusions: RVG-circSCMH1-EVs afford protection by promoting functional recovery in the rodent and the nonhuman primate ischemic stroke models. Our study presents a potentially widely applicable nucleotide drug delivery technology and demonstrates the basic mechanism of how circRNAs can be therapeutically exploited to improve post-stroke outcomes.

Background and Purpose— Circular RNAs (CircRNAs) show promise as stroke biomarkers because of their participation in various pathophysiological processes associated with acute ischemic stroke (AIS) and stability in peripheral blood. Methods— A circRNA microarray was used to identify differentially expressed circulating circRNAs in a discovery cohort (3 versus 3). Validation (36 versus 36) and replication (200 versus 100) were performed in independent cohorts by quantitative polymerase chain reaction. Platelets, lymphocytes, and granulocytes were separated from blood to examine the origins of circRNAs. Results— There were 3 upregulated circRNAs in Chinese population–based AIS patients compared with healthy controls. The combination of 3 circRNAs resulted in an area under the curve of 0.875, corresponding to a specificity of 91% and a sensitivity of 71.5% in AIS diagnosis. Furthermore, the combination of change rate in 3 circRNAs within the first 7 days of treatment showed an area under the curve of 0.960 in predicting stroke outcome. There was significant increase in lymphocytes and granulocytes for circPDS5B (circular RNA PDS5B) and only in granulocytes for circCDC14A (circular RNA CDC14A) in AIS patients compared with healthy controls. Conclusions— Three circRNAs could serve as biomarkers for AIS diagnosis and prediction of stroke outcomes. The elevated levels of circPDS5B and circCDC14A after stroke might be because of increased levels in lymphocytes and granulocytes.

BACKGROUND: N 6-methyladenosine (m 6 A) is the most abundant epigenetic modification in eukaryotic messenger RNAs and is essential for multiple RNA processing events in physiological and pathological processes. However, precisely how m 6 A methylation is involved in major depressive disorder (MDD) is not fully understood. METHODS: Circular RNA STAG1 (circSTAG1) was screened from the hippocampus of chronic unpredictable stresstreated mice using high-throughput RNA sequencing. Microinjection of circSTAG1 lentivirus into the mouse hippocampus was used to observe the role of circSTAG1 in depression. Sucrose preference, forced swim, and tail suspension tests were performed to evaluate the depressive-like behaviors of mice. Astrocyte dysfunction was examined by GFAP immunostaining and 3D reconstruction. Methylated RNA immunoprecipitation sequence analysis was used to identify downstream targets of circSTAG1/ALKBH5 (alkB homolog 5) axis. Cell Counting Kit-8 assay was performed to evaluate astrocyte viability in vitro. RESULTS: circSTAG1 was significantly decreased in the chronic unpredictable stress-treated mouse hippocampus and in peripheral blood of patients with MDD. Overexpression of circSTAG1 notably attenuated astrocyte dysfunction and depressive-like behaviors induced by chronic unpredictable stress. Further examination indicated that overexpressed circSTAG1 captured ALKBH5 and decreased the translocation of ALKBH5 into the nucleus, leading to increased m 6 A methylation of fatty acid amide hydrolase (FAAH) messenger RNA and degradation of FAAH in astrocytes with subsequent attenuation of depressive-like behaviors and astrocyte loss induced by corticosterone in vitro. CONCLUSIONS: Our findings dissect the functional link between circSTAG1 and m 6 A methylation in the context of MDD, providing evidence that circSTAG1 may be a novel therapeutic target for MDD.

The development of versatile nanoplatforms with efficient tumor-targeting properties and synergistic therapeutic strategies to realize effective antitumor efficiency are highly anticipated in the field of cancer therapy. Herein, we innovatively synthesized targeted nanocomplexes (NCGO-FA) with nanoscale structures by a modified Hummers' method and then used these nanocomplexes to separately load the doxorubicin (DOX) and methylene blue (MB) via π−π stacking, electrostatic attractions, and/or hydrophobic interactions,

Multifunctional core‐shell structural nanoparticles (NPs) integrating of therapeutic and imaging modalities have presented superior prospects as drug delivery systems in the treatment of cancer. In this work, graphene quantum dots (GQDs) and doxorubicin (DOX) were encapsulated into the cores of PLGA (Poly (D, L‐lactide‐co‐glycolide)) nanoparticles coated with bovine serum albumin via a double emulsion‐solvent evaporation method to construct pH‐responsive nanoparticles (DOX/PB and GQDs@DOX/PB NPs) with spherical core‐shell structures. Subsequently, the cellular uptake, cytotoxicity and biocompatibility of the NPs were studied via in vitro experiments. The results demonstrated that DOX/PB NPs and GQDs@DOX/PB NPs exhibit high drug‐loading efficiency and promote the release of DOX in a mild acidic microenvironment, which was expected to result in intelligent intracellular drug carriers. In vitro cytotoxicity measurements showed that all the NPs exhibit dose‐ and time‐dependent cytotoxicity to the HeLa cells and PLGA NPs loaded with GQDs contribute to reducing cancer cell viability. Moreover, no significant difference in ROS level was determined during the endocytosis. In addition, all the NPs displayed excellent blood compatibility by hemolysis assay. These results demonstrate that pH‐responsive NPs may be excellent candidates for efficient cancer therapy and in vivo biological imaging probes.