Downregulation of miR-26b attenuates early brain injury induced by subarachnoid hemorrhage via mediating the KLF4/STAT3/HMGB1 axis

A review of KLF4 and inflammatory disease: Current status and future perspective

Inflammation is the response of the human body to injury, infection, or other abnormal states, which is involved in the development of many diseases. As a member of the Krüppel-like transcription factors (KLFs) family, KLF4 plays a crucial regulatory role in physiological and pathological processes due to its unique dual domain of transcriptional activation and inhibition. A growing body of evidence has demonstrated that KLF4 plays a pivotal role in the pathogenesis of various inflammatory disorders, including inflammatory bowel disease, osteoarthritis, renal inflammation, pneumonia, neuroinflammation, and so on. Consequently, KLF4 has emerged as a promising new therapeutic target for inflammatory diseases. This review systematically generalizes the molecular regulatory network, specific functions, and mechanisms of KLF4 to elucidate its complex roles in inflammatory diseases. An in-depth study on the biological function of KLF4 is anticipated to offer a novel research perspective and potential intervention strategies for inflammatory diseases.

Ferroptosis in early brain injury after subarachnoid hemorrhage: review of literature

Spontaneous subarachnoid hemorrhage (SAH), mainly caused by ruptured intracranial aneurysms, is a serious acute cerebrovascular disease. Early brain injury (EBI) is all brain injury occurring within 72 h after SAH, mainly including increased intracranial pressure, decreased cerebral blood flow, disruption of the blood-brain barrier, brain edema, oxidative stress, and neuroinflammation. It activates cell death pathways, leading to neuronal and glial cell death, and is significantly associated with poor prognosis. Ferroptosis is characterized by iron-dependent accumulation of lipid peroxides and is involved in the process of neuron and glial cell death in early brain injury. This paper reviews the research progress of ferroptosis in early brain injury after subarachnoid hemorrhage and provides new ideas for future research.

Neuronal pyroptosis mediated by STAT3 in early brain injury after subarachnoid hemorrhage

Neuroinflammation induced by early brain injury (EBI) seriously affects the prognosis of patients after subarachnoid hemorrhage (SAH). Pyroptosis can aggravate inflammatory injury by promoting the secretion of inflammatory cytokines. Meanwhile, STAT3 plays a critical role in the inflammatory response of EBI after SAH. However, whether it plays a pyroptotic role in SAH is mainly unknown. This study aimed to explore the mechanism of STAT3 in pyroptosis in EBI after SAH. C57BL/6J mice were used to establish the SAH model. Brain tissues were collected at different time points for q-RT-PCR and western blot to detect the expression level of STAT3. After intracerebroventricular injection of STAT3 inhibitor S3I-201, they were divided into sham, SAH, SAH + Vehicle, and SAH + S3I-201. Then, the SAH grade, cerebral edema content, blood-brain barrier (BBB) damage, and neurological scores of mice in each group were detected. qRT-PCR and western blot were used to detect related genes and proteins, and enzyme-linked immunosorbent assay (ELISA) was used to detect the expression levels of IL-18 and IL-1β. Immunofluorescence staining was used to observe the expression level of proteins. At the same time, S3I-201 was added to the primary neuron cells of the culture medium containing OxyHb to simulate the in vitro experiment, and the relevant indicators consistent with the in vivo experiment were detected. The expression of STAT3 was upregulated after SAH. Inhibition of STAT3 with S3I-201 attenuated neurological deficits, cerebral edema, and BBB damage after SAH. In addition, S3I-201 can also reduce the expression of pyroptosis-related inflammasomes such as GSDMD, NLRP3, Caspase 1, and AIM2 after SAH and the neurological damage caused by IL-18 and IL-1β. Further studies have shown that STAT3 regulates pyroptosis by promoting the nuclear translocation of NF-κB p65. Our finding demonstrated that STAT3 regulates neuronal pyroptosis in EBI after SAH. Inhibition of STAT3 may be a potential target to attenuate the damage that triggers neuroinflammation after SAH.

Small Molecule Regulators of microRNAs Identified by High-Throughput Screen Coupled with High-Throughput Sequencing

MicroRNAs (miRNAs) regulate fundamental biological processes by silencing mRNA targets and are dysregulated in many diseases. Therefore, miRNA replacement or inhibition can be harnessed as potential therapeutics. However, existing strategies for miRNA modulation using oligonucleotides and gene therapies are challenging, especially for neurological diseases, and none have yet gained clinical approval. We explore a different approach by screening a biodiverse library of small molecule compounds for their ability to modulate hundreds of miRNAs in human induced pluripotent stem cell-derived neurons. We demonstrate the utility of the screen by identifying cardiac glycosides as potent inducers of miR-132, a key miRNA downregulated in Alzheimer's disease and other tauopathies. Coordinately, cardiac glycosides downregulate known miR-132 targets, including Tau, and protect rodent and human neurons against various toxic insults. More generally, our dataset of 1370 drug-like compounds and their effects on the miRNome provide a valuable resource for further miRNA-based drug discovery.

Diagnosis potential of subarachnoid hemorrhage using miRNA signatures isolated from plasma-derived extracellular vesicles

The diagnosis and clinical management of aneurysmal subarachnoid hemorrhage (aSAH) is currently limited by the lack of accessible molecular biomarkers that reflect the pathophysiology of disease. We used microRNAs (miRNAs) as diagnostics to characterize plasma extracellular vesicles in aSAH. It is unclear whether they can diagnose and manage aSAH. Next-generation sequencing (NGS) was used to detect the miRNA profile of plasma extracellular vesicles (exosomes) in three patients with SAH and three healthy controls (HCs). We identified four differentially expressed miRNAs and validated the results using quantitative real-time polymerase chain reaction (RT-qPCR) with 113 aSAH patients, 40 HCs, 20 SAH model mice, and 20 sham mice. Exosomal miRNA NGS revealed that six circulating exosomal miRNAs were differentially expressed in patients with aSAH versus HCs and that the levels of four miRNAs (miR-369-3p, miR-410-3p, miR-193b-3p, and miR-486-3p) were differentially significant. After multivariate logistic regression analysis, only miR-369-3p, miR-486-3p, and miR-193b-3p enabled prediction of neurological outcomes. In a mouse model of SAH, greater expression of miR-193b-3p and miR-486-3p remained statistically significant relative to controls, whereas expression levels of miR-369-3p and miR-410-3p were lower. miRNA gene target prediction showed six genes associated with all four of these differentially expressed miRNAs. The circulating exosomes miR-369-3p, miR-410-3p, miR-193b-3p, and miR-486-3p may influence intercellular communication and have potential clinical utility as prognostic biomarkers for aSAH patients.