Subarachnoid hemorrhage (SAH) is a neurological emergency characterized by dysfunctional inflammatory response. However, no effective therapeutic options have been reported so far. Microglia polarization has been proposed to exert an essential role in modulating inflammatory response after SAH. Sestrin2 is a stress response protein. Growing evidence has reported that sestrin2 could inhibit M1 microglia and promote M2 microglia polarization. The current study investigated the effects of sestrin2 on microglia phenotype switching and the subsequent brain injury and sought to elucidate the underlying mechanism. We conducted an endovascular perforation SAH model in mice. It was found that sestrin2 was significantly increased after SAH and was mainly distributed in neurons and microglia. Exogenous recombinant human sestrin2 (rh-sestrin2) evidently alleviated inflammatory insults and oxidative stress, and improved neurofunction after SAH. Moreover, rh-sestrin2 increased M2-like microglia polarization and suppressed the number of M1-like microglia after SAH. The protection by rh-sestrin2 was correlated with the activation of Nrf2 signaling. Nrf2 inhibition by ML385 abated the cerebroprotective effects of rh-sestrin2 against SAH and further manifested M1 microglia polarization. In conclusion, promoting microglia polarization from the M1 to M2 phenotype and inducing Nrf2 signaling might be the major mechanism by which sestrin2 protects against SAH insults. Sestrin2 might be a new molecular target for treating SAH.

Background: Extracellular vesicles (EVs) are produced during abnormal and normal physiological conditions. Understanding the expression profile of microRNA (miRNA) in plasma-derived small extracellular vesicles (sEVs) and their roles in subarachnoid hemorrhage (SAH) that cause cerebral vasospasm (CVS) is imperative. Methods: Sprague Dawley rats (250-300 g) were allocated to sham or SAH groups established using endovascular perforation method. miRNA expression profiles of plasma sEVs in both groups (each n = 4) were evaluated using next-generation sequencing (NGS). Results: There were 142 microRNAs (miRNAs) significantly expressed differently between the two groups, of which 73 were up-regulated while 69 were down-regulated in SAH sEVs compared with those of sham (p < 0.05; fold change ≥ 2). The Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway and Gene Ontology (GO) analyses of differently expressed (DE) miRNAs revealed signaling pathways and target genes (TGs) in the SAH group. rno-miR-185-5p, rno-miR-103-3p, rno-miR-15b-3p, rno-miR-93-5p, and rno-miR-98-5p were the top five most up-regulated sEVs miRNAs. Conclusion: Our results suggest that miRNA can be selectively packaged into sEVs under SAH, and this could help develop potential targets for the prevention, diagnosis, and treatment of CVS after this condition.

Background: Cerebral ischemia-reperfusion (CI/R) injury is a subtype of complication after treatment of ischemic stroke. It has been reported that exosomes derived from BMSCs could play an important role in CI/R injury. However, whether BMSCs-derived exosomes could regulate CI/R injury via carrying miRNAs remains to be further explored. Methods: RNA sequencing was performed to identify the differentially expressed miRNAs. To mimic CI/R in vitro, SH-SY5Y cells were exposed to oxygen glucose deprivation/reoxygenation (OGD/R). The viability of SH-SY5Y cells was tested by CCK8 assay, and TUNEL staining was performed to detect the cell apoptosis. Results: MiR-133a-3p was identified to be reduced in exosomes derived from the plasma of patients with IS. Upregulation of miR-133a-3p significantly reversed OGD/R-induced SH-SY5Y cell growth inhibition. Consistently, BMSCs-derived exosomal miR-133a-3p could restore OGD/R-decreased SH-SY5Y cell proliferation via inhibiting apoptosis. Meanwhile, DAPK2 was a direct target of miR-133a-3p. In addition, OGD/R notably upregulated the level of DAPK2 and weakened the expressions of p-Akt and p-mTOR in SH-SY5Y cells, whereas exosomal miR-133a-3p derived from BMSCs notably reversed these phenomena. Exosomal miR-133a-3p derived from BMSCs could reverse OGD/R-induced cell apoptosis via inhibiting autophagy. Furthermore, exosomal miR-133a-3p derived from BMSCs markedly alleviated the symptom of CI/R injury in vivo. Conclusion: Exosomal miR-133a-3p derived from BMSCs alleviates CI/R injury via targeting DAPK2/Akt signaling. Thus, our study might shed new light on discovering new strategies against CI/R injury.

Background A large amount of evidence has shown the necessity of lowering blood pressure (BP) in patients with acute cerebral hemorrhage, but whether reducing BP contributes to lower short-term and long-term mortality in these patients remains uncertain. Aims We aimed to explore the association between BP, including systolic and diastolic BP, during intensive care unit (ICU) admission and 1-month and 1-year mortality after discharge of patients with cerebral hemorrhage. Methods A total of 1085 patients with cerebral hemorrhage were obtained from the Medical Information Mart for Intensive Care III (MIMIC-III) database. Maximum and minimum values of systolic and diastolic BP in these patients during their ICU stay were recorded, and endpoint events were defined as the 1-month mortality and 1-year mortality after the first admission. Multivariable adjusted models were performed for the association of BP with the endpoint events. Results We observed that patients with hypertension were likely to be older, Asian or Black and had worse health insurance and higher systolic BP than those without hypertension. The logistic regression analysis showed inverse relationships between systolic BP-min (odds ratio (OR) = 0.986, 95% CI 0.983–0.989, P < 0.001) and diastolic BP-min (OR = 0.975, 95% CI 0.968–0.981, P < 0.001) and risks of 1-month, as well as 1-year mortality when controlling for confounders including age, sex, race, insurance, heart failure, myocardial infarct, malignancy, cerebral infarction, diabetes and chronic kidney disease. Furthermore, smooth curve analysis suggested an approximate L-shaped association of systolic BP with the risk of 1-month mortality and 1-year mortality. Reducing systolic BP in the range of 100–150 mmHg has a lower death risk in these patients with cerebral hemorrhage. Conclusion We observed an L-shaped association between systolic BP levels and the risks of 1-month and 1-year mortality in patients with cerebral hemorrhage, which supported that lowering BP when treating an acute hypertensive response could reduce short-term and long-term mortality.