Neuroinflammation and blood-brain barrier (BBB) disruption are two critical mechanisms of subarachnoid hemorrhage (SAH)-induced brain injury, which are closely related to patient prognosis. Recently, angiogenic factor with G-patch and FHA domain 1 (Aggf1) was shown to inhibit inflammatory effect and preserve vascular integrity in non-nervous system diseases. This study aimed to determine whether Aggf1 could attenuate neuroinflammation and preserve BBB integrity after experimental SAH, as well as the underlying mechanisms of its protective roles. Two hundred forty-nine male Sprague-Dawley rats were subjected to the endovascular perforation model of SAH. Recombinant human Aggf1 (rh-Aggf1) was administered intravenously via tail vein injection at 1 h after SAH induction. To investigate the underlying neuroprotection mechanism, Aggf1 small interfering RNA (Aggf1 siRNA) and PI3K-specific inhibitor LY294002 were administered through intracerebroventricular (i.c.v.) before SAH induction. SAH grade, neurological score, brain water content, BBB permeability, Western blot, and immunohistochemistry were performed. Expression of endogenous Aggf1 was markedly increased after SAH. Aggf1 was primarily expressed in endothelial cells and astrocytes, as well as microglia after SAH. Administration of rh-Aggf1 significantly reduced brain water content and BBB permeability, decreased the numbers of infiltrating neutrophils, and activated microglia in the ipsilateral cerebral cortex following SAH. Furthermore, rh-Aggf1 treatment improved both short- and long-term neurological functions after SAH. Meanwhile, exogenous rh-Aggf1 significantly increased the expression of PI3K, p-Akt, VE-cadherin, Occludin, and Claudin-5, as well as decreased the expression of p-NF-κB p65, albumin, myeloperoxidase (MPO), TNF-α, and IL-1β. Conversely, knockdown of endogenous Aggf1 aggravated BBB breakdown, inflammatory response and neurological impairments at 24 h after SAH. Additionally, the protective roles of rh-Aggf1 were abolished by LY294002. Taken together, exogenous Aggf1 treatment attenuated neuroinflammation and BBB disruption, improved neurological deficits after SAH in rats, at least in part through the PI3K/Akt/NF-κB pathway.

Background: Neuroinflammation and blood-brain barrier (BBB) disruption are two vital mechanisms of secondary brain injury following intracerebral hemorrhage (ICH). Recently, melanocortin-1 receptor (Mc1r) activation by Nle4-D-Phe7-α-MSH (NDP-MSH) was shown to play a neuroprotective role in an experimental autoimmune encephalomyelitis (EAE) mouse model. This study aimed to investigate whether NDP-MSH could alleviate neuroinflammation and BBB disruption after experimental ICH, as well as the potential mechanisms of its neuroprotective roles. Methods: Two hundred and eighteen male C57BL/6 mice were subjected to autologous blood-injection ICH model. NDP-MSH, an agonist of Mc1r, was administered intraperitoneally injected at 1 h after ICH insult. To further explore the related protective mechanisms, Mc1r small interfering RNA (Mc1r siRNA) and nuclear receptor subfamily 4 group A member 1 (Nr4a1) siRNA were administered via intracerebroventricular (i.c.v) injection before ICH induction. Neurological test, BBB permeability, brain water content, immunofluorescence staining, and Western blot analysis were implemented. Results: The Expression of Mc1r was significantly increased after ICH. Mc1r was mainly expressed in microglia, astrocytes, and endothelial cells following ICH. Treatment with NDP-MSH remarkably improved neurological function and reduced BBB disruption, brain water content, and the number of microglia in the peri-hematoma tissue after ICH. Meanwhile, the administration of NDP-MSH significantly reduced the expression of p-NF-κB p65, IL-1β, TNF-α, and MMP-9 and increased the expression of p-CREB, Nr4a1, ZO-1, occludin, and Lama5. Inversely, the knockdown of Mc1r or Nr4a1 abolished the neuroprotective effects of NDP-MSH. Conclusions: Taken together, NDP-MSH binding Mc1r attenuated neuroinflammation and BBB disruption and improved neurological deficits, at least in part through CREB/Nr4a1/NF-κB pathway after ICH.

Neuroinflammation has been proven to exert an important effect on brain injury after intracerebral hemorrhage (ICH). Previous studies reported that Didymin possessed anti-inflammatory properties after acute hepatic injury, hyperglycemia-induced endothelial dysfunction, and death. However, the role of Didymin in microglial pyroptosis and neuroinflammation after ICH is unclear. The current study aimed to investigate the effect of Didymin on neuroinflammation mediated by microglial pyroptosis in mouse models of ICH and shed some light on the underlying mechanisms. In this study, we observed that Didymin treatment remarkably improved neurobehavioral performance and decreased BBB disruption and brain water content. Microglial activation and neutrophil infiltration in the peri-hematoma tissue after ICH were strikingly mitigated by Didymin as well. At the molecular level, administration of Didymin significantly unregulated the expression of Rkip and downregulated the expression of pyroptotic molecules and inflammatory cytokines such as Nlrp3 inflammasome, GSDMD, caspase-1, and mature IL-1β, TNF-α, and MPO after ICH. Besides, Didymin treatment decreased the number of Caspase-1-positive microglia and GSDMD-positive microglia after ICH. Inversely, Locostatin, an Rkip-specific inhibitor, significantly abolished the anti-pyroptosis and anti-neuroinflammation effects of Didymin. Moreover, Rkip binding with Asc could interrupt the activation and assembly of the inflammasome. Mechanistically, inhibition of Caspase-1 by VX-765 attenuated brain injury and suppressed microglial pyroptosis and neuroinflammation by downregulation of GSDMD, mature IL-1β, TNF-α, and MPO based on Locostatin-treated ICH. Taken together, Didymin alleviated microglial pyroptosis and neuroinflammation, at least in part through the Asc/Caspase-1/GSDMD pathway via upregulating Rkip expression after ICH. Therefore, Didymin may be a potential agent to attenuate neuroinflammation via its anti-pyroptosis effect after ICH.

Background: Oral contraceptive (OCP) use might increase the risk of stroke in women. We examined a possible dose–response relation between OCP use and the risk of stroke in young and middle-aged women. Methods: A retrieval of PubMed and EMBASE databases was performed. We selected observational studies that reported odds ratios (ORs) with 95% confidence intervals (CIs) for the risk of stroke in OCP users. A two-stage dose–response analysis was conducted using the random-effects model and the restricted spline model. Results: A total of 6 cohort studies and 12 case–control studies were included, which involved 2,143,174 participants and 11,661 cases of stroke including ischemic stroke (IS), hemorrhagic stroke (HS), and stroke of unknown origin. The pooled ORs of total stroke were 1.19 (95% CI, 1.16–1.23) for every 10-μg increment in estrogen dosage, 1.20 (95% CI, 1.05–1.37) for every 5-years increment in duration of OCP use, and 0.82 (95% CI, 0.68–0.98) for every 5-years increment in duration of OCP cessation. The ORs of IS were 1.20 (95% CI, 1.17–1.22) in estrogen dosage, 1.24 (95% CI, 1.04–1.49) in duration of OCP use, and 0.78 (95% CI, 0.67–0.92) in duration of OCP cessation. The ORs of HS were 1.10 (95% CI, 1.04–1.16) in estrogen dosage, 1.13 (95% CI, 0.93–1.36) in duration of OCPs, and 0.71 (95% CI, 0.55–0.92) in duration of OCP cessation. The pooled ORs of total stroke from prospective studies (1.12; 95% CI, 1.01–1.24) were lower than those from retrospective studies (1.30; 95% CI, 1.01–1.67). Conclusions: The higher estrogen dosage significantly increased the risks of total stroke, IS, and HS, respectively. The longer duration of OCP use significantly increased the risks of total stroke and IS, but its effects on HS risk were marginal. The longer duration of OCP cessation significantly decreased the risks of total stroke, IS, and HS, respectively. These findings affirm the contribution of estrogen dose and duration of OCP use to the increased risk of stroke, which may be critical for the instruction of OCP use and the prevention and management of cerebrovascular diseases.

Oxidative stress and neuronal apoptosis play crucial roles in secondary brain injury (SBI) after intracerebral hemorrhage (ICH). Recently, Nle4-D-Phe7-α-melanocyte-stimulating hormone (NDP-MSH), a synthetic agonist of the melanocortin-1 receptor (Mc1r), has been proved to inhibit neuroinflammatory in several diseases. This study is aimed at exploring if NDP-MSH could reduce oxidative stress and neuronal apoptosis following ICH, as well as the potential mechanism. A mouse ICH model was induced by autologous blood injection. NDP-MSH was intraperitoneally injected at 1h after ICH. Mc1r siRNA and PI3K inhibitor LY294002 were administrated to inhibit the expression of Mc1r and phosphorylation of PI3K, respectively. Neurological test, brain water content, enzyme-linked immunosorbent assay (ELISA), terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL), immunofluorescence, and Western blot analysis were utilized in this study. The results exhibited that Mc1r was mainly expressed in neurons, and its level in the ipsilateral hemisphere was significantly elevated after ICH. NDP-MSH treatment significantly attenuated the neurological deficits and brain water content 24 hours after ICH, which was accompanied by the inhibition of oxidative stress and neuronal apoptosis. The administration of NDP-MSH after ICH significantly promoted the expression of Mc1r, p-PI3K, p-Akt, and p-Nrf2, followed by an increase of Bcl-2 and reduction of cleaved caspase-3. Conversely, downregulating the expression of Mc1r and phosphorylation of PI3K aggravated the neurological deficits and brain edema at 24 hours after ICH, meanwhile, the effect of NDP-MSH on the expression of Mc1r, p-PI3K, p-Akt, p-Nrf2, Bcl-2, and cleaved caspase 3 was also abolished. In conclusion, our data suggest that the activation of Mc1r by NDP-MSH ameliorates oxidative stress and neuronal apoptosis through the PI3K/Akt/Nrf2 signaling pathway after ICH in mice.