Background and Purpose: Neuronal pyroptosis is a type of regulated cell death triggered by proinflammatory signals. CCR5 (C-C chemokine receptor 5)-mediated inflammation is involved in the pathology of various neurological diseases. This study investigated the impact of CCR5 activation on neuronal pyroptosis and the underlying mechanism involving cAMP-dependent PKA (protein kinase A)/CREB (cAMP response element binding)/NLRP1 (nucleotide-binding domain leucine-rich repeat pyrin domain containing 1) pathway after experimental intracerebral hemorrhage (ICH). Methods: A total of 194 adult male CD1 mice were used. ICH was induced by autologous whole blood injection. Maraviroc (MVC)—a selective antagonist of CCR5—was administered intranasally 1 hour after ICH. To elucidate the underlying mechanism, a specific CREB inhibitor, 666-15, was administered intracerebroventricularly before MVC administration in ICH mice. In a set of naive mice, rCCL5 (recombinant chemokine ligand 5) and selective PKA activator, 8-Bromo-cAMP, were administered intracerebroventricularly. Short- and long-term neurobehavioral assessments, Western blot, Fluoro-Jade C, terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL), and immunofluorescence staining were performed. Results: The brain expression of CCL5 (chemokine ligand 5), CCR5, PKA-Cα (protein kinase A-Cα), p-CREB (phospho-cAMP response element binding), and NLRP1 was increased, peaking at 24 hours after ICH. CCR5 was expressed on neurons, microglia, and astrocytes. MVC improved the short- and long-term neurobehavioral deficits and decreased neuronal pyroptosis in ipsilateral brain tissues at 24 hours after ICH, which were accompanied by increased PKA-Cα and p-CREB expression, and decreased expression of NLRP1, ASC (apoptosis-associated speck-like protein containing a CARD), C-caspase-1, GSDMD (gasdermin D), and IL (interleukin)-1β/IL-18. Such effects of MVC were abolished by 666-15. At 24 hours after injection in naive mice, rCCL5 induced neurological deficits, decreased PKA-Cα and p-CREB expression in the brain, and upregulated NLRP1, ASC, C-caspase-1, N-GSDMD, and IL-1β/IL-18 expression. Those effects of rCCL5 were reversed by 8-Bromo-cAMP. Conclusions: CCR5 activation promoted neuronal pyroptosis and neurological deficits after ICH in mice, partially through the CCR5/PKA/CREB/NLRP1 signaling pathway. CCR5 inhibition with MVC may provide a promising therapeutic approach in managing patients with ICH.

Background and Purpose: Neuroinflammation has been proven to play an important role in the pathogenesis of early brain injury after subarachnoid hemorrhage (SAH). EZH2 (enhancer of zeste homolog 2)-mediated H3K27Me3 (trimethylation of histone 3 lysine 27) has been recognized to play a critical role in multiple inflammatory diseases. However, there is still a lack of evidence to address the effect of EZH2 on the immune response of SAH. Therefore, the aim of this study was to determine the role of EZH2 in SAH-induced neuroinflammation and explore the effect of EZH2 inhibition with its specific inhibitor EPZ6438. Methods: The endovascular perforation method was performed on rats to induce subarachnoid hemorrhage. EPZ6438, a specific EZH2 inhibitor, was administered intraperitoneally at 1 hour after SAH. SOCS3 (Suppressor of cytokine signaling 3) siRNA and H3K27me3 CRISPR were administered intracerebroventricularly at 48 hours before SAH to explore potential mechanisms. The SAH grade, short-term and long-term neurobehavioral tests, immunofluorescence staining, and western blots were performed after SAH. Results: The expression of EZH2 and H3K27me3 peaked at 24 hours after SAH. In addition, inhibition of EZH2 with EPZ6438 significantly improved neurological deficits both in short-term and long-term outcome studies. Moreover, EPZ6438 treatment significantly decreased the levels of EZH2, H3K27Me3, pathway-related proteins TRAF6 (TNF [tumor necrosis factor] receptor family 6), NF-κB (nuclear factor-κB) p65, proinflammatory cytokines TNF-α, IL (interleukin)-6, IL-1β, but increased the expression levels of SOCS3 and anti-inflammatory cytokine IL-10. Furthermore, administration of SOCS3 siRNA and H3k27me3-activating CRISPR partly abolished the neuroprotective effect of EPZ6438, which indicated that the neuroprotective effect of EPZ6438 acted, at least partly, through activation of SOCS3. Conclusions: In summary, the inhibition of EZH2 by EPZ6438 attenuated neuroinflammation via H3K27me3/SOCS3/TRAF6/NF-κB signaling pathway after SAH in rats. By targeting EZH2, this study may provide an innovative method to ameliorate early brain injury after SAH.

Knowledge about the dynamic metabolism and function of cerebrospinal fluid (CSF) physiology has rapidly progressed in recent decades. It has traditionally been suggested that CSF is produced by the choroid plexus and drains to the arachnoid villi. However, recent findings have revealed that the brain parenchyma produces a large portion of CSF and drains through the perivascular glymphatic system and meningeal lymphatic vessels into the blood. The primary function of CSF is not limited to maintaining physiological CNS homeostasis but also participates in clearing waste products resulting from neurodegenerative diseases and acute brain injury. Aneurysmal subarachnoid hemorrhage (SAH), a disastrous subtype of acute brain injury, is associated with high mortality and morbidity. Post-SAH complications contribute to the poor outcomes associated with SAH. Recently, abnormal CSF flow was suggested to play an essential role in the post-SAH pathophysiological changes, such as increased intracerebral pressure, brain edema formation, hydrocephalus, and delayed blood clearance. An in-depth understanding of CSF dynamics in post-SAH events would shed light on potential development of SAH treatment options. This review summarizes and updates the latest physiological characteristics of CSF dynamics and discusses potential pathophysiological changes and therapeutic targets after SAH.

Stroke has a high rate of morbidity and disability, which seriously endangers human health. In stroke, oxidative stress leads to further damage to the brain tissue. Therefore, treatment for oxidative stress is urgently needed. However, antioxidative drugs have demonstrated obvious protective effects in preclinical studies, but the clinical studies have not seen breakthroughs. Nanomaterials, with their characteristically small size, can be used to deliver drugs and have demonstrated excellent performance in treating various diseases. Additionally, some nanomaterials have shown potential in scavenging reactive oxygen species (ROS) in stroke according to the nature of nanomaterials. The drugs’ delivery ability of nanomaterials has great significance for the clinical translation and application of antioxidants. It increases drug blood concentration and half‐life and targets the ischemic brain to protect cells from oxidative stress‐induced death. This review summarizes the characteristics and progress of nanomaterials in the application of antioxidant therapy in stroke, including ischemic stroke, hemorrhagic stroke, and neural regeneration. We also discuss the prospect of nanomaterials for the treatment of oxidative stress in stroke and the challenges in their application, such as the toxicity and the off‐target effects of nanomaterials.

Oxidative stress (OS) and neuronal apoptosis are major pathological processes after hypoxic-ischemic encephalopathy (HIE). Colony stimulating factor 1 (CSF1), binding to CSF1 receptor (CSF1R), has been shown to reduce neuronal loss after hypoxic-ischemia- (HI-) induced brain injury. In the present study, we hypothesized that CSF1 could alleviate OS-induced neuronal degeneration and apoptosis through the CSF1R/PLCG2/PKA/UCP2 signaling pathway in a rat model of HI. A total of 127 ten-day old Sprague Dawley rat pups were used. HI was induced by right common carotid artery ligation with subsequent exposure to hypoxia for 2.5 h. Exogenous recombinant human CSF1 (rh-CSF1) was administered intranasally at 1 h and 24 h after HI. The CSF1R inhibitor, BLZ945, or phospholipase C-gamma 2 (PLCG2) inhibitor, U73122, was injected intraperitoneally at 1 h before HI induction. Brain infarct volume measurement, cliff avoidance test, righting reflex test, double immunofluorescence staining, western blot assessment, 8-OHdG and MitoSOX staining, Fluoro-Jade C staining, and TUNEL staining were used. Our results indicated that the expressions of endogenous CSF1, CSF1R, p-CSF1R, p-PLCG2, p-PKA, and uncoupling protein2 (UCP2) were increased after HI. CSF1 and CSF1R were expressed in neurons and astrocytes. Rh-CSF1 treatment significantly attenuated neurological deficits, infarct volume, OS, neuronal apoptosis, and degeneration at 48 h after HI. Moreover, activation of CSF1R by rh-CSF1 significantly increased the brain tissue expressions of p-PLCG2, p-PKA, UCP2, and Bcl2/Bax ratio, but reduced the expression of cleaved caspase-3. The neuroprotective effects of rh-CSF1 were abolished by BLZ945 or U73122. These results suggested that rh-CSF1 treatment attenuated OS-induced neuronal degeneration and apoptosis after HI, at least in part, through the CSF1R/PLCG2/PKA/UCP2 signaling pathway. Rh-CSF1 may serve as therapeutic strategy against brain damage in patients with HIE.

Stroke is a devastating disease that occurs when a blood vessel in the brain is either blocked or ruptured, consequently leading to deficits in neurological function. Stroke consistently ranked as one of the top causes of mortality, and with the mean age of incidence decreasing, there is renewed interest to seek novel therapeutic treatments. The Scavenger Receptor Class B type 1 (SR-B1) is a multifunctional protein found on the surface of a variety of cells. Research has found that that SR-B1 primarily functions in an anti-inflammatory and anti-atherosclerotic capacity. In this review, we discuss the characteristics of SR-B1 and focus on its potential correlation with the modifiable risk factors of stroke. SR-B1 likely has an impact on stroke through its interaction with smoking, diabetes mellitus, diet, physical inactivity, obesity, hypercholesterolemia, atherosclerosis, coronary heart disease, hypertension, and sickle cell disease, all of which are critical risk factors in the pathogenesis of stroke.