NLRP3 Inflammasome in the Pathophysiology of Hemorrhagic Stroke: A Review

The regulatory effect of intermittent fasting on inflammasome activation in health and disease

Intermittent fasting (IF), one of the most popular diets, can regulate inflammation and promote health; however, the detailed molecular mechanisms are not fully understood. The present review aims to provide an overview of recent preclinical and clinical studies that have examined the effect of IF on inflammasome signaling, and to discuss the translational gap between preclinical and clinical studies. Three databases (PubMed, Web of Science, and Embase) were searched to identify all relevant preclinical and clinical studies up to October 30, 2022. A total of 1544 studies were identified through the database searches, and 29 preclinical and 10 clinical studies were included. Twenty-three of the 29 preclinical studies reported that IF treatment could reduce inflammasome activation in neurological diseases, metabolic and cardiovascular diseases, immune and inflammatory diseases, gastrointestinal diseases, and pulmonary diseases, and 7 of the 10 clinical studies demonstrated reduced inflammasome activation after IF intervention in both healthy and obese participants. Among various IF regimens, time-restricted eating seemed to be the most effective one in terms of inflammasome regulation, and the efficacy of IF might increase over time. This review highlights the regulatory effect of IF on inflammasome activation in health and disease. Future studies using different IF regimens, in various populations, are needed in order to evaluate its potential to be used alone or as an adjunct therapy in humans to improve health and counteract diseases.

Dysregulation of the Gut Microbiota Contributes to Sevoflurane-Induced Cognitive Dysfunction in Aged Mice by Activating the NLRP3 Inflammasome

Postoperative cognitive dysfunction (POCD), a common complication in elderly patients after surgery, seriously affects patients' quality of life. Long-term or repeated inhalation of sevoflurane can cause neuroinflammation, which is a risk factor for POCD. However, the underlying mechanism needs to be further explored. Recent research had revealed a correlation between neurological disorders and changes in the gut microbiota. Dysfunction of the gut microbiota is involved in the occurrence and development of central nervous system diseases. Here, we found that cognitive dysfunction in aged mice induced by sevoflurane exposure (3%, 2 hours daily, for 3 days) was related to gut microbiota dysbiosis, while probiotics improved cognitive function by alleviating dysbiosis. Sevoflurane caused a significant decrease in the abundance of Akkermansia (P<0.05), while probiotics restored the abundance of Akkermansia. Compared to those in the control group, sevoflurane significantly increased the expression of NLRP3 inflammasome-associated proteins in the gut and brain in the sevoflurane-exposed group, thus causing neuroinflammation and synaptic damage, which probiotics can mitigate (con vs. sev, P < 0.01; p+sev vs. sev, P < 0.05). In conclusion, for the first time, our study revealed that dysbiosis of the gut microbiota caused by sevoflurane anesthesia contributes to the NLRP3 inflammasome-mediated neuroinflammation and cognitive dysfunction from the perspective of the gut-brain axis. Perhaps postoperative cognitive impairment in elderly patients can be alleviated or even prevented by regulating the gut microbiota. This study provides new insights and methods for the prevention and treatment of cognitive impairment induced by sevoflurane.

Cystatin C Attenuates Perihematomal Secondary Brain Injury by Inhibiting the Cathepsin B/NLRP3 Signaling Pathway in a Rat Model of Intracerebral Hemorrhage

Secondary brain injury (SBI) is a noticeable contributor to the high mortality and morbidity rates associated with intracerebral hemorrhage (ICH), and effective treatment options remain limited. Cystatin C (CysC) emerges as a novel candidate for SBI intervention. The therapeutic effects and underlying mechanisms of CysC in mitigating SBI following ICH were explored in the current research. An in vivo ICH rat model was established by injecting autologous blood into the right caudate nucleus. Western blotting (WB) was utilized to assess the levels of CysC, cathepsin B (CTSB), and the NLRP3 inflammasome. Subsequently, the ICH rat model was treated with exogenous CysC supplementation or CysC knockdown plasmids. Various parameters, including Evans blue (EB) extravasation, brain water content, and neurological function in rats, were examined. RT-qPCR and WB were employed to determine the expression levels of CTSB and the NLRP3 inflammasome. The co-expression of CTSB, CysC, and NLRP3 inflammasome with GFAP, NeuN, and Iba1 was assessed through double-labeled immunofluorescence. The interaction between CysC and CTSB was investigated using double-labeled immunofluorescence and co-immunoprecipitation. The findings revealed an elevation of CysC expression level, particularly at 24 h after ICH. Exogenous CysC supplementation alleviated severe brain edema, neurological deficit scores, and EB extravasation induced by ICH. Conversely, CysC knockdown produced opposite effects. The expression levels of CTSB and the NLRP3 inflammasome were significantly risen following ICH, and exogenous CysC supplement attenuated their expression levels. Double-labeled immunofluorescence illustrated that CysC, CTSB, and the NLRP3 inflammasome were predominantly expressed in microglial cells, and the interaction between CysC and CTSB was evidenced. CysC exhibited potential in ameliorating SBI following ICH via effectively suppressing the activation of the NLRP3 inflammasome mediated by CTSB specifically in microglial cells. These findings underscore the prospective therapeutic efficacy of CysC in the treatment of ICH-induced complications.

The NLRP3 inhibitor, OLT1177 attenuates brain injury in experimental intracerebral hemorrhage

BACKGROUND AND PURPOSE

It has been reported activation of NLRP3 inflammasome after intracerebral hemorrhage (ICH) ictus exacerbates neuroinflammation and brain injury. We hypothesized that inhibition of NLRP3 by OLT1177 (dapansutrile), a novel NLRP3 inflammasome inhibitor, could reduce brain edema and attenuate brain injury in experimental ICH.

METHODS

ICH was induced by injection of autologous blood into basal ganglia in mice models. Sixty-three C57Bl/6 male mice were randomly grouped into the sham, vehicle, OLT1177 (Dapansutrile, 200 mg/kg intraperitoneally) and treated for consecutive three days, starting from 1 h after ICH surgery. Behavioral test, brain edema, brain water content, blood-brain barrier integrity and vascular permeability, cell apoptosis, and NLRP3 and its downstream protein levels were measured.

RESULTS

OLT1177 significantly reduced cerebral edema after ICH and contributed to the attenuation of neurological deficits. OLT1177 could preserve blood-brain barrier integrity and lessen vascular leakage. In addition, OLT1177 preserved microglia morphological shift and significantly inhibited the activation of caspase-1 and release of IL-1β. We also found that OLT1177 can protect against neuronal loss in the affected hemisphere.

CONCLUSIONS

OLT1177 (dapansutrile) could significantly attenuate the brain edema after ICH and effectively alleviate the neurological deficit. This result suggests that the novel NLRP3 inhibitor, OLT1177, might serve as a promising candidate for the treatment of ICH.

Vagus nerve stimulation as a promising neuroprotection for ischemic stroke via α7nAchR-dependent inactivation of microglial NLRP3 inflammasome

Ischemic stroke is a major cause of disability and death worldwide, and its management requires urgent attention. Previous studies have shown that vagus nerve stimulation (VNS) exerts neuroprotection in ischemic stroke by inhibiting neuroinflammation and apoptosis. In this study, we evaluated the timing for VNS intervention in ischemic stroke, and the underlying mechanisms  of VNS-induced neuroprotection. Mice were subjected to transient middle cerebral artery occlusion (tMCAO) for 60 min. The left vagus nerve at cervical level was exposed and attached to an electrode connected to a low-frequency electrical stimulator. Vagus nerve stimulation (VNS) was given for 60 min before, during and after tMCAO (Pre-VNS, Dur-VNS, Post-VNS). Neurological function was assessed 24 h after reperfusion. We found that all the three VNS significantly protected against the tMCAO-induced injury evidenced by improved neurological function and reduced infarct volume. Moreover, the Pre-VNS was the most effective against the ischemic injury. We found that tMCAO activated microglia in the ischemic core and penumbra regions of the brain, followed by the NLRP3 inflammasome activation-induced neuroinflammation, which finally triggered neuronal death. VNS treatment preserved α7nAChR expression in the penumbra regions, inhibited NLRP3 inflammasome activation and ensuing neuroinflammation, rescuing cerebral neurons. The role of α7nAChR in microglial NLRP3 inflammasome activation in ischemic stroke was further validated using genetic manipulations, including Chrna7 knockout mice and microglial Chrna7 overexpression mice, as well as pharmacological interventions using the α7nAChR inhibitor methyllycaconitine and agonist PNU-282987. Collectively, this study demonstrates the potential of VNS as a safe and effective strategy to treat ischemic stroke, and presents a new approach targeting microglial NLRP3 inflammasome, which might be therapeutic for other inflammation-related diseases.

Simultaneous antioxidant and neuroprotective effects of two-dimensional (2D) MXene-loaded isoquercetin for ischemic stroke treatment

Oxidative stress and reactive oxygen species drive ischemic stroke and its related complications. New antioxidant medications are therefore crucial for treating ischemic stroke. We developed Ti2C@BSA-ISO nanocomposites loaded with the hydrophobic drug isoquercetin (ISO) encapsulated in BSA on Ti2C nano-enzymes as a novel therapeutic nanomedicine for the treatment of ischemic stroke targeting reactive oxygen species (ROS). TEM visually proved the successful preparation of Ti2C@BSA-ISO, and the FTIR, XPS, zeta potential and DLS together demonstrated the acquisition of Ti2C@BSA-ISO. In addition, the enzyme-mimicking activity of Ti2C was evaluated and the antioxidant capacity of Ti2C@BSA-ISO was verified. Ti2C@BSA-ISO was able to reverse the decrease in cellular activity caused by ROS. Experiments in vivo showed that Ti2C@BSA-ISO could promote neuroprotection and scavenging of ROS in the hippocampal CA1 area and cerebral cortex of rats, thereby inhibiting cellular death and alleviating ischaemic stroke. Specifically, Ti2C@BSA-ISO alleviated ischemic stroke by inhibiting NLRP3/caspase-1/GSDMD pathway-mediated pyroptosis. Our study demonstrates the effectiveness of nanomedicines that can be directly used as drugs for the treatment of ischemic stroke in synergy with other drugs, which greatly expands the application of nanomaterials in the treatment of ischemic stroke.

Role of CD36 in central nervous system diseases

CD36 is a highly glycosylated integral membrane protein that belongs to the scavenger receptor class B family and regulates the pathological progress of metabolic diseases. CD36 was recently found to be widely expressed in various cell types in the nervous system, including endothelial cells, pericytes, astrocytes, and microglia. CD36 mediates a number of regulatory processes, such as endothelial dysfunction, oxidative stress, mitochondrial dysfunction, and inflammatory responses, which are involved in many central nervous system diseases, such as stroke, Alzheimer's disease, Parkinson's disease, and spinal cord injury. CD36 antagonists can suppress CD36 expression or prevent CD36 binding to its ligand, thereby achieving inhibition of CD36-mediated pathways or functions. Here, we reviewed the mechanisms of action of CD36 antagonists, such as Salvianolic acid B, tanshinone IIA, curcumin, sulfosuccinimidyl oleate, antioxidants, and small-molecule compounds. Moreover, we predicted the structures of binding sites between CD36 and antagonists. These sites can provide targets for more efficient and safer CD36 antagonists for the treatment of central nervous system diseases.

Mitophagy in intracerebral hemorrhage: a new target for therapeutic intervention

Intracerebral hemorrhage is a life-threatening condition with a high fatality rate and severe sequelae. However, there is currently no treatment available for intracerebral hemorrhage, unlike for other stroke subtypes. Recent studies have indicated that mitochondrial dysfunction and mitophagy likely relate to the pathophysiology of intracerebral hemorrhage. Mitophagy, or selective autophagy of mitochondria, is an essential pathway to preserve mitochondrial homeostasis by clearing up damaged mitochondria. Mitophagy markedly contributes to the reduction of secondary brain injury caused by mitochondrial dysfunction after intracerebral hemorrhage. This review provides an overview of the mitochondrial dysfunction that occurs after intracerebral hemorrhage and the underlying mechanisms regarding how mitophagy regulates it, and discusses the new direction of therapeutic strategies targeting mitophagy for intracerebral hemorrhage, aiming to determine the close connection between mitophagy and intracerebral hemorrhage and identify new therapies to modulate mitophagy after intracerebral hemorrhage. In conclusion, although only a small number of drugs modulating mitophagy in intracerebral hemorrhage have been found thus far, most of which are in the preclinical stage and require further investigation, mitophagy is still a very valid and promising therapeutic target for intracerebral hemorrhage in the long run.

Intracerebral Hemorrhage-Induced Brain Injury: the Role of Lysosomal-Associated Transmembrane Protein 5

Intracerebral hemorrhage (ICH) is a lethal stroke with high mortality or disability. However, effective therapy for ICH damage is generally lacking. Previous investigations have suggested that lysosomal protein transmembrane 5 (LAPTM5) is involved in various pathological processes, including autophagy, apoptosis, and inflammation. In this study, we aimed to identify the expression and functions of LAPTM5 in collagenase-induced ICH mouse models and hemoglobin-induced cell models. We found that LAPTM5 was highly expressed in brain tissues around the hematoma, and double immunostaining studies showed that LAPTM5 was co-expressed with microglia cells, neurons, and astrocytes. Following ICH, the mice presented increased brain edema, blood-brain barrier permeability, and neurological deficits, while pathological symptoms were alleviated after the LAPTM5 knockdown. Adeno-associated virus 9-mediated downregulation of LAPTM5 also improves ICH-induced secondary cerebral damage, including neuronal degeneration, the polarization of M1-like microglia, and inflammatory cascades. Furthermore, LAPTM5 promoted activation of the nuclear factor kappa-B (NF-κB) pathway in response to neuroinflammation. Further investigations indicated that brain injury improved by LAPTM5 knockdown was further exacerbated after the overexpression of receptor-interacting protein kinase 1 (RIP1), which is revealed to trigger the NF-κB pathway. In vitro experiments demonstrated that LAPTM5 silencing inhibited hemoglobin-induced cell function and confirmed regulation between RIP1 and LAPTM5. In conclusion, the present study indicates that LAPTM5 may act as a positive regulator in the context of ICH by modulating the RIP1/NF-κB pathway. Thus, it may be a candidate gene for further study of molecular or therapeutic targets.

Remote limb ischemic postconditioning inhibits microglia pyroptosis by modulating HGF after acute ischemia stroke

The repetitive inflation-deflation of a blood pressure cuff on a limb is known as remote limb ischemic postconditioning (RIPostC). It prevents brain damage induced by acute ischemia stroke (AIS). Pyroptosis, executed by the pore-forming protein gasdermin D (GSDMD), is a type of regulated cell death triggered by proinflammatory signals. It contributes to the pathogenesis of ischemic brain injury. However, the effects of RIPostC on pyroptosis following AIS remain largely unknown. In our study, linear correlation analysis confirmed that serum GSDMD levels in AIS patients upon admission were positively correlated with NIHSS scores. RIPostC treatment significantly reduced GSDMD level compared with patients without RIPostC at 3 days post-treatment. Besides, middle cerebral artery occlusion (MCAO) surgery was performed on C57BL/6 male mice and RIPostC was induced immediately after MCAO. We found that RIPostC suppressed the activation of NLRP3 inflammasome to reduce the maturation of GSDMD, leading to decreased pyroptosis in microglia after AIS. Hepatocyte growth factor (HGF) was identified using the high throughput screening. Importantly, HGF siRNA, exogenous HGF, and ISG15 siRNA were used to reveal that HGF/ISG15 is a possible mechanism of RIPostC regulation in vivo and in vitro.

Scientific Landscape of Oxidative Stress in Stroke: From a Bibliometric Analysis to an in-Depth Review

Stroke is an acute cerebrovascular disease resulting from either obstruction or rupture of a blood vessel in the brain. Oxidative stress (OS), referred to a status where cellular oxidative capacities overwhelm antioxidative defenses, is involved in the pathophysiology of stroke. The bibliometric analysis and in-depth review aim to depict the research trend of OS in stroke. Relevant scientific publications were acquired from the Web of Science Core Collection database. Scientific landscape of OS in stroke was illustrated by general quantitative trend, impactful journals, and co-authorship of various academic units (i.e., countries/regions, organizations, and authors). Furthermore, theme analysis predicting the hot research issues and frontiers was performed. 15,826 documents regarding OS in stroke were obtained over a time span of more than 20 years from 1992 to 2021. The overall tendency of publication counts was continuously on the rise. Bibliometric analysis indicated China and the United States were predominant in this study field, as reflected by their high publication counts and intensive collaboration with other countries. Current key research areas of OS in stroke may lie in the investigation of neuroinflammation, and interaction among multiple cell death mechanisms including apoptosis, autophagy, and ferroptosis to search for effective treatments. Moreover, another hot topic could be the association between air pollution and stroke, and its underlying mechanisms. As the exploration of OS in stroke is speculated to be a continuous hot spot in the future, this article may be helpful for researchers to conduct future studies with the understanding of influential academic forces and research highlights.

HIF-1, an important regulator in potential new therapeutic approaches to ischemic stroke

Ischemic stroke is a leading cause of disability and mortality worldwide due to the narrow therapeutic window of the only approved therapies like intravenous thrombolysis and thrombectomy. Hypoxia inducible factor-1α (HIF-1α) is a sensitive regulator of oxygen homeostasis, and its expression is rapidly induced after hypoxia/ischemia. It plays an extensive role in the pathophysiology of stroke by regulating multiple pathways including glucose metabolism, angiogenesis, neuronal survival, neuroinflammation and blood brain barrier regulation. Here, we give a brief overview of the HIF-1α-targeting strategies currently under investigation and summarise recent research on how HIF-1α is regulated in various brain cells, including neurons and microglia, at various stages in ischemic stroke. The roles of HIF-1 in stroke varies with ischemic time and degree of ischemia, are still up for debate. More focus has been placed on prospective HIF-1α targeting drugs, such as HIF-1α activator, HIF-1α stabilizers, and natural compounds. In this review, we have highlighted the regulation of HIF-1α in the novel therapeutic approaches for treatment of stroke.

Partial blood replacement ameliorates middle cerebral artery occlusion generated neurological aberrations by intervening TLR4 and NLRP3 cascades in rats

Acute ischemic stroke is a catastrophic medical condition that causes severe disability and mortality if the sufferer escapes treatment within a stipulated timeframe. While timely intervention with clot-bursting agents like tissue-plasminogen activators abrogates some post-stroke neurologic deficits, no neuroprotective therapy is yet promisingly addresses the post-recanalization neuroinflammation in post-stroke survivors. Herein, we investigated the effect of partial blood replacement therapy (BRT), obtained from healthy and treadmill-trained donor rats, on neurological deficits, and peripheral and central inflammatory cascades using the ischemia-reperfusion animal paradigm. The cerebral ischemia-reperfusion was induced in rats by occlusion of the middle cerebral artery (MCAO) for 90 min, followed by reperfusion. Rats underwent MCAO surgery displayed remarkable sensorimotor and motor deficits in rotarod, foot fault, adhesive removal, and paw whisker tests till 5 days post-surgery. These behavior abnormalities were ameliorated in the BRT-recipient MCAO rats. BRT also reduced the infarct volume and neuronal death in the ipsilateral hemisphere revealed by TTC and cresyl violet staining compared to the MCAO group. Rats received BRT infusion exhibited the reduced expression of glial fibrillary acidic protein, ionized calcium-binding adaptor molecule-1 (Iba-1), and MyD88 on day 5 post-MCAO in immunohistochemistry and immunofluorescent assays. Moreover, elevated levels of toll-like receptor 4 (TLR4) and mRNA expression of IL-1β, TNF-α, matrix metalloproteinase-9 and NLRP3, and decreased levels of zonula occludens-1 in MCAO rats, were reversed following BRT. These findings suggest that the partial BRT may rescind MCAO-induced neurological dysfunctions and cerebral injury by intervening in the TLR4 and NLRP3 pathways in rats.

VCAM-1+ hUC-MSCs Exert Considerable Neuroprotection Against Cerebral Infarction in Rats by Suppression of NLRP3-Induced Pyroptosis

Mesenchymal stem/stromal cells (MSCs) are spindle-like heterogeneous cell populations with advantageous bidirectional immunomodulatory and hematopoietic support effects. Vascular cellular adhesion molecule-1 (VCAM-1)+ MSCs have been reported to exhibit immunoregulatory and proangiogenic capacities. Here, we studied the effects of VCAM-1+ human umbilical cord (hUC)-MSCs on neuroprotection against cerebral infarction. Sprague-Dawley rats were subjected to middle cerebral artery occlusion (MCAO), and VCAM-1- and VCAM-1+ hUC-MSCs were intravenously injected into the rat 4 h post-MCAO surgery. Thereafter, modified neurological severity scores (mNSS) were determined, and the Morris water maze test, 2,3,5-triphenyltetrazolium chloride (TTC), hematoxylin and eosin (H&E), Nissl, TUNEL staining, and qRT-PCR were conducted. Following induction of oxygen-glucose deprivation/reoxygenation (OGD/R), SH-SY5Y cells were co-cultured with VCAM-1- and VCAM-1+ hUC-MSCs. CCK-8, flow cytometry, ELISA, and western blot analyses were performed in vitro. Compared with VCAM-1- hUC-MSCs, administration of VCAM-1+ hUC-MSCs revealed improved therapeutic efficacy against cerebral infarction in rats, as confirmed by lower mNSS scores and infarct volumes, as well as improved learning and memory capacities. In addition, VCAM-1+ hUC-MSCs exhibited improved efficacy against neurological defects in rats with cerebral infarction, accompanied by inhibition of the NLRP3-mediated inflammatory response. VCAM-1+ hUC-MSC co-culture improved the viability and diminished NLRP3-mediated inflammatory response in OGD/R-treated SH-SY5Y cells. Moreover, NLRP3 overexpression in SH-SY5Y cells prevented the beneficial effects of VCAM-1+ hUC-MSC co-culture. Overall, our findings demonstrated the relevance of VCAM-1+ hUC-MSC-based cytotherapy for preclinical neuroprotection against cerebral infarction.

Mesenchymal stem cells (MSCs) and MSC-derived exosomes in animal models of central nervous system diseases: Targeting the NLRP3 inflammasome

The NLRP3 (NOD-, LRR-, and pyrin domain-containing protein 3) inflammasome is a multimeric protein complex that is engaged in the innate immune system and plays a vital role in inflammatory reactions. Activation of the NLRP3 inflammasome and subsequent release of proinflammatory cytokines can be triggered by microbial infection or cellular injury. The NLRP3 inflammasome has been implicated in the pathogenesis of many disorders affecting the central nervous system (CNS), ranging from stroke, traumatic brain injury, and spinal cord injury to Alzheimer's disease, Parkinson's disease, epilepsy, multiple sclerosis, and depression. Furthermore, emerging evidence has suggested that mesenchymal stem cells (MSCs) and their exosomes may modulate NLRP3 inflammasome activation in a way that might be promising for the therapeutic management of CNS diseases. In the present review, particular focus is placed on highlighting and discussing recent scientific evidence regarding the regulatory effects of MSC-based therapies on the NLRP3 inflammasome activation and their potential to counteract proinflammatory responses and pyroptotic cell death in the CNS, thereby achieving neuroprotective impacts and improvement in behavioral impairments.

Serum amyloid A-dependent inflammasome activation and acute injury in a mouse model of experimental stroke

Serum amyloid A (SAA) proteins increase dramatically in the blood following inflammation. Recently, SAAs are increased in humans following stroke and in ischemic animal models. However, the impact of SAAs on whether this signal is critical in the ischemic brain remains unknown. Therefore, we investigated the role of SAA and SAA signaling in the ischemic brain. Wildtype and SAA deficient mice were exposed to middle cerebral artery occlusion and reperfusion, examined for the impact of infarct volumes, behavioral changes, inflammatory markers, TUNEL staining, and BBB changes. The underlying mechanisms were investigated using SAA deficient mice, transgenic mice and viral vectors. SAA levels were significantly increase following MCAo and mice deficient in SAAs showed reduced infarct volumes and improved behavioral outcomes. SAA deficient mice showed a reduction in TUNEL staining, inflammation and decreased glial activation. Mice lacking acute phase SAAs demonstrated a reduction in expression of the NLRP3 inflammasome and SAA/NLRP3 KO mice showed improvement. Restoration of SAA expression via SAA tg mice or adenoviral expression reestablished the detrimental effects of SAA. A reduction in BBB permeability was seen in the SAA KO mice and anti-SAA antibody treatment reduced the effects on ischemic injury. SAA signaling plays a critical role in regulating NLRP3-induced inflammation and glial activation in the ischemic brain. Blocking this signal will be a promising approach for treating ischemic stroke.

LncRNA Gm44206 Promotes Microglial Pyroptosis Through NLRP3/Caspase-1/GSDMD Axis and Aggravate Cerebral Ischemia-Reperfusion Injury

Inhibition of the inflammatory response triggered by microglial pyroptosis inflammatory activation may be one of the effective ways to alleviate cerebral ischemia-reperfusion injury, the specific mechanism of which remains unclear. In this study, BV-2 microglia with or without oxygen-glucose deprivation/reoxygenation (OGD/R) or long noncoding RNA (lncRNA) Gm44206 knockdown were used as cell models to conduct an in vitro study. Detection of lactate dehydrogenase release and pyroptosis-related protein levels was performed using a corresponding kit and western blotting, respectively. Proliferation of microglia was evaluated by CCK8 assay. Enzyme-linked immunosorbent assay was applied for measuring levels of proinflammatory cytokines. This study verified the involvement of microglial pyroptosis as well as upregulation of NLRP3, Caspase-1, GSDMD, and Apoptosis-associated Speck-like protein containing a C-terminal caspase-recruitment domain (ASC) in cerebral ischemia-reperfusion injury. Moreover, knockdown of lncRNA Gm44206 could alleviate OGD/R-induced microglial pyroptosis and cell proliferation inhibition through the NLRP3/Caspase-1/GSDMD pathway, thus decreasing the release of proinflammatory cytokines, including interleukin (IL)-1β, IL-6, IL-18, and tumor necrosis factor-alpha. In conclusion, this study established a correlation between microglial pyroptosis and cerebral ischemia-reperfusion injury and identified lncRNA Gm44206 as a potential regulator of NLRP3/Caspase-1/GSDMD axis-mediated microglial pyroptosis, which could be considered a promising therapeutic target.

The Potential of NLRP3 Inflammasome as a Therapeutic Target in Neurological Diseases

NLRP3 (NLRP3: NOD-, LRR-, and pyrin domain-containing protein 3) inflammasome is the best-described inflammasome that plays a crucial role in the innate immune system and a wide range of diseases. The intimate association of NLRP3 with neurological disorders, including neurodegenerative diseases and strokes, further emphasizes its prominence as a clinical target for pharmacological intervention. However, after decades of exploration, the mechanism of NLRP3 activation remains indefinite. This review highlights recent advances and gaps in our insights into the regulation of NLRP3 inflammasome. Furthermore, we present several emerging pharmacological approaches of clinical translational potential targeting the NLRP3 inflammasome in neurological diseases. More importantly, despite small-molecule inhibitors of the NLRP3 inflammasome, we have focused explicitly on Chinese herbal medicine and botanical ingredients, which may be splendid therapeutics by inhibiting NLRP3 inflammasome for central nervous system disorders. We expect that we can contribute new perspectives to the treatment of neurological diseases.

Monomeric and dimeric guaianolide sesquiterpenoids with hypoglycemic activity from Achillea alpina

Three new monomeric (1-3) and two newdimeric guaianolides (4 and 5), along with three known analogues (6-8) were isolated from the aerial part of Achillea alpina L. Compounds 1-3 were three novel 1,10-seco-guaianolides, while 4 and 5 were two novel 1,10-seco-guaianolides involved heterodimeric [4 + 2] adducts. The new structures were elucidated by analysis of spectroscopic data and quantum chemical calculations. All isolates were evaluated for their hypoglycemic activity with a glucose consumption model in palmitic acid (PA)-induced HepG2-insulin resistance (IR) cells, and compound 1 showed the most promising activity. A mechanistic study revealed that compound 1 appeared to mediate hypoglycemic activity via inhibition of the ROS/TXNIP/NLRP3/caspase-1 pathway.

Thiolutin attenuates ischemic stroke injury via inhibition of NLRP3 inflammasome: an in vitro and in vivo study

A recent study confirmed that thiolutin is effective in the treatment of nucleotide-binding domain-like receptor protein 3 (NLRP3)-related inflammatory diseases. Nevertheless, whether thiolutin (THL) is involved in the regulation of NLRP3 inflammasome in ischemic stroke is not known. The murine neuronal cell oxygen-glucose deprivation (OGD) model was first established, and then different concentrations (25 nM and 50 nM) of THL were administered for 48 h incubation, respectively. Subsequently, cell viability and toxicity, and the levels of intracellular inflammatory factors interleukin-1β (IL-1β), interleukin-18 (IL-18), oxidative stress factors superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), catalase (CAT) and malondialdehyde (MDA), and NLRP3 inflammasome activation-related proteins pro-caspase, caspase-1, apoptosis-associated speck like-protein (ASC) and NLRP3 were examined, respectively. We further established the mouse middle cerebral artery occlusion (MCAO) model to evaluate the therapeutic effects of THL on cerebral infarction like behaviors in mice and the preventive effects on NLRP3 inflammasome activation in vivo. Cell cytotoxic, and the levels of inflammatory factors and oxidative stress were conspicuously increased, and NLRP3 inflammasome was materially activated in the OGD-induced cell model and MCAO-established mouse model, which were partially countered by THL treatment. Besides, intraperitoneal injection of THL could prominently reduce the cerebral infarct volume and neuromotor deficit scores in MCAO mice. The present study confirmed that THL attenuated neuronal and cerebral inflammatory injury caused by OGD and MCAO models in mice through restraining NLRP3 inflammasome activation in vitro and in vivo.

Autophagy regulates inflammation in intracerebral hemorrhage: Enemy or friend?

Intracerebral hemorrhage (ICH) is the second-largest stroke subtype and has a high mortality and disability rate. Secondary brain injury (SBI) is delayed after ICH. The main contributors to SBI are inflammation, oxidative stress, and excitotoxicity. Harmful substances from blood and hemolysis, such as hemoglobin, thrombin, and iron, induce SBI. When cells suffer stress, a critical protective mechanism called "autophagy" help to maintain the homeostasis of damaged cells, remove harmful substances or damaged organelles, and recycle them. Autophagy plays a critical role in the pathology of ICH, and its function remains controversial. Several lines of evidence demonstrate a pro-survival role for autophagy in ICH by facilitating the removal of damaged proteins and organelles. However, many studies have found that heme and iron can aggravate SBI by enhancing autophagy. Autophagy and inflammation are essential culprits in the progression of brain injury. It is a fascinating hypothesis that autophagy regulates inflammation in ICH-induced SBI. Autophagy could degrade and clear pro-IL-1β and apoptosis-associated speck-like protein containing a CARD (ASC) to antagonize NLRP3-mediated inflammation. In addition, mitophagy can remove endogenous activators of inflammasomes, such as reactive oxygen species (ROS), inflammatory components, and cytokines, in damaged mitochondria. However, many studies support the idea that autophagy activates microglia and aggravates microglial inflammation via the toll-like receptor 4 (TLR4) pathway. In addition, autophagy can promote ICH-induced SBI through inflammasome-dependent NLRP6-mediated inflammation. Moreover, some resident cells in the brain are involved in autophagy in regulating inflammation after ICH. Some compounds or therapeutic targets that regulate inflammation by autophagy may represent promising candidates for the treatment of ICH-induced SBI. In conclusion, the mutual regulation of autophagy and inflammation in ICH is worth exploring. The control of inflammation by autophagy will hopefully prove to be an essential treatment target for ICH.

Dual roles of anesthetics in postoperative cognitive dysfunction: Regulation of microglial activation through inflammatory signaling pathways

Postoperative cognitive dysfunction (POCD) is a prevalent clinical entity following surgery and is characterized by declined neurocognitive function. Neuroinflammation mediated by microglia is the essential mechanism of POCD. Anesthetics are thought to be a major contributor to the development of POCD, as they promote microglial activation and induce neuroinflammation. However, this claim remains controversial. Anesthetics can exert both anti- and pro-inflammatory effects by modulating microglial activation, suggesting that anesthetics may play dual roles in the pathogenesis of POCD. Here, we review the mechanisms by which the commonly used anesthetics regulate microglial activation via inflammatory signaling pathways, showing both anti- and pro-inflammatory properties of anesthetics, and indicating how perioperative administration of anesthetics might either relieve or worsen POCD development. The potential for anesthetics to enhance cognitive performance based on their anti-inflammatory properties is further discussed, emphasizing that the beneficial effects of anesthetics vary depending on dose, exposure time, and patients' characteristics. To minimize the incidence of POCD, we recommend considering these factors to select appropriate anesthetics.

Role of SIRT3 in neurological diseases and rehabilitation training

Sirtuin3 (SIRT3) is a deacetylase that plays an important role in normal physiological activities by regulating a variety of substrates. Considerable evidence has shown that the content and activity of SIRT3 are altered in neurological diseases. Furthermore, SIRT3 affects the occurrence and development of neurological diseases. In most cases, SIRT3 can inhibit clinical manifestations of neurological diseases by promoting autophagy, energy production, and stabilization of mitochondrial dynamics, and by inhibiting neuroinflammation, apoptosis, and oxidative stress (OS). However, SIRT3 may sometimes have the opposite effect. SIRT3 can promote the transfer of microglia. Microglia in some cases promote ischemic brain injury, and in some cases inhibit ischemic brain injury. Moreover, SIRT3 can promote the accumulation of ceramide, which can worsen the damage caused by cerebral ischemia-reperfusion (I/R). This review comprehensively summarizes the different roles and related mechanisms of SIRT3 in neurological diseases. Moreover, to provide more ideas for the prognosis of neurological diseases, we summarize several SIRT3-mediated rehabilitation training methods.

Research progress on pyroptosis-mediated immune-inflammatory response in ischemic stroke and the role of natural plant components as regulator of pyroptosis: A review

Ischemic stroke (IS) is one of the leading causes of death and disability. Its pathogenesis is not completely clear, and inflammatory cascade is one of its main pathological processes. The current clinical practice of IS is to restore the blood supply to the ischemic area after IS as soon as possible through thrombolytic therapy to protect the vitality and function of neurons. However, blood reperfusion further accelerates ischemic damage and cause ischemia-reperfusion injury. The pathological process of cerebral ischemia-reperfusion injury involves multiple mechanisms, and the exact mechanism has not been fully elucidated. Pyroptosis, a newly discovered form of inflammatory programmed cell death, plays an important role in the initiation and progression of inflammation. It is a pro-inflammatory programmed death mediated by caspase Caspase-1/4/5/11, which can lead to cell swelling and rupture, release inflammatory factors IL-1β and IL-18, and induce an inflammatory cascade. Recent studies have shown that pyroptosis and its mediated inflammatory response are important factors in aggravating ischemic brain injury, and inhibition of pyroptosis may alleviate the ischemic brain injury. Furthermore, studies have found that natural plant components may have a regulatory effect on pyroptosis. Therefore, this review not only summarizes the molecular mechanism of pyroptosis and its role in ischemic stroke, but also the role of natural plant components as regulator of pyroptosis, in order to provide reference information on pyroptosis for the treatment of IS in the future.

New Insights of Early Brain Injury after Subarachnoid Hemorrhage: A Focus on the Caspase Family

Spontaneous subarachnoid hemorrhage (SAH), primarily caused by ruptured intracranial aneurysms, remains a prominent clinical challenge with a high rate of mortality and morbidity worldwide. Accumulating clinical trials aiming at the prevention of cerebral vasospasm (CVS) have failed to improve the clinical outcome of patients with SAH. Therefore, a growing number of studies have shifted focus to the pathophysiological changes that occur during the periods of early brain injury (EBI). New pharmacological agents aiming to alleviate EBI have become a promising direction to improve outcomes after SAH. Caspases belong to a family of cysteine proteases with diverse functions involved in maintaining metabolism, autophagy, tissue differentiation, regeneration, and neural development. Increasing evidence shows that caspases play a critical role in brain pathology after SAH. Therefore, caspase regulation could be a potential target for SAH treatment. Herein, we provide an overview pertaining to the current knowledge on the role of caspases in EBI after SAH, and we discuss the promising therapeutic value of caspase-related agents after SAH.

Secondary White Matter Injury Mediated by Neuroinflammation after Intracerebral Hemorrhage and Promising Therapeutic Strategies of Targeting the NLRP3 Inflammasome

Intracerebral hemorrhage (ICH) is a neurological disease with high mortality and disability. Recent studies showed that white matter injury (WMI) plays an important role in motor dysfunction after ICH. WMI includes WMI proximal to the lesion and WMI distal to the lesion, such as corticospinal tract injury located at the cervical enlargement of the spinal cord after ICH. Previous studies have tended to focus only on gray matter (GM) injury after ICH, and fewer studies have paid attention to WMI, which may be one of the reasons for the poor outcome of previous drug treatments. Microglia and astrocyte-mediated neuroinflammation are significant mechanisms responsible for secondary WMI following ICH. The NOD-like receptor family, pyrin domain-containing 3 (NLRP3) inflammasome activation, has been shown to exacerbate neuroinflammation and brain injury after ICH. Moreover, NLRP3 inflammasome is activated in microglia and astrocytes and exerts a vital role in microglia and astrocytes-mediated neuroinflammation. We speculate that NLRP3 inflammasome activation is closely related to the polarization of microglia and astrocytes and that NLRP3 inflammasome activation may exacerbate WMI by polarizing microglia and astrocytes to the pro-inflammatory phenotype after ICH, while NLRP3 inflammasome inhibition may attenuate WMI by polarizing microglia and astrocytes to the anti-inflammatory phenotype following ICH. Therefore, NLRP3 inflammasome may act as leveraged regulatory fulcrums for microglia and astrocytes polarization to modulate WMI and WM repair after ICH. This review summarized the possible mechanisms by which neuroinflammation mediated by NLRP3 inflammasome exacerbates secondary WMI after ICH and discussed the potential therapeutic targets.

Glial Cells Response in Stroke

As the second-leading cause of death, stroke faces several challenges in terms of treatment because of the limited therapeutic interventions available. Previous studies primarily focused on metabolic and blood flow properties as a target for treating stroke, including recombinant tissue plasminogen activator and mechanical thrombectomy, which are the only USFDA approved therapies. These interventions have the limitation of a narrow therapeutic time window, the possibility of hemorrhagic complications, and the expertise required for performing these interventions. Thus, it is important to identify the contributing factors that exacerbate the ischemic outcome and to develop therapies targeting them for regulating cellular homeostasis, mainly neuronal survival and regeneration. Glial cells, primarily microglia, astrocytes, and oligodendrocytes, have been shown to have a crucial role in the prognosis of ischemic brain injury, contributing to inflammatory responses. They play a dual role in both the onset as well as resolution of the inflammatory responses. Understanding the different mechanisms driving these effects can aid in the development of therapeutic targets and further mitigate the damage caused. In this review, we summarize the functions of various glial cells and their contribution to stroke pathology. The review highlights the therapeutic options currently being explored and developed that primarily target glial cells and can be used as neuroprotective agents for the treatment of ischemic stroke.

Exploring the Neuroprotective Mechanism of Curcumin Inhibition of Intestinal Inflammation against Parkinson's Disease Based on the Gut-Brain Axis

Parkinson's disease (PD) is a chronic progressive neurodegenerative disease commonly seen in aged people, in which gastrointestinal dysfunction is the most common nonmotor symptom and the activation of the gut-brain axis by intestinal inflammation may contribute to the pathogenesis of PD. In a previous study, curcumin was considered neuroprotective in PD, and this neuroprotective mechanism may act by inhibiting intestinal inflammation. Therefore, the aim of this study was to evaluate the effect of curcumin on motor dysfunction and the loss of dopaminergic neurons in a PD mouse model, induced by N-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) using open field test and pole test behavioral assessments and the immunofluorescence and Western blot methods. Moreover, the effects of curcumin on gastrointestinal dysfunction, gastric barrier function, pro-inflammatory cytokines, and the SIRT1/NRF2 pathway in intestinal tissues in a PD mouse model were assessed using fecal parameters and intestinal dynamics, immunofluorescence, ELISA, and Western blot. A motor impairment study of an MPTP-induced mouse group prior to treatment with curcumin had a lower total movement distance and a slow average speed, while there was no statistical difference in the curcumin group. After treatment with curcumin, the total movement distance and average speed improved, the tyrosine hydroxylase (TH) rate in the substantia nigra pars compacta (SNpc) and striatum were reduced, the pyroptosis of AIM2 and caspase-1 activations were inhibited, and intestinal inflammatory factors and intestinal inflammation were reduced. Curcumin improved gastrointestinal disorders and gastrointestinal barrier function in the MPTP-induced mice and reversed MPTP-induced motor dysfunction and dopaminergic neuron loss in mice. The above effects may be partly dependent on curcumin activation of the SIRT1/NRF2 pathway in the colon. This study provides a potential opportunity to develop new preventive measures and novel therapeutic approaches that could target the gut-brain axis in the context of PD and provide a new intervention in the treatment of Parkinson's disease.

Inhibition of Dectin-1 Alleviates Neuroinflammatory Injury by Attenuating NLRP3 Inflammasome-Mediated Pyroptosis After Intracerebral Hemorrhage in Mice: Preliminary Study Results

BACKGROUND

Neuroinflammation plays an important role following intracerebral hemorrhage (ICH). NLRP3 inflammasome-mediated pyroptosis contributes to the mechanism of neuroinflammation. It has been reported that dendritic cell-associated C-type lectin-1 (Dectin-1) activation triggers inflammation in neurological diseases. However, the role of Dectin-1 on NLRP3 inflammasome-mediated pyroptosis after ICH remains unclear. Here, we aimed to explore the effect of Dectin-1 on NLRP3 inflammasome-mediated pyroptosis and neuroinflammation after ICH.

METHODS

Adult male C57BL/6 mice were used to establish the ICH model. Laminarin, an inhibitor of Dectin-1, was administered for intervention. Expression of Dectin-1 was evaluated by Western blot and immunofluorescence. Brain water content and neurobehavioral function were tested to assess brain edema and neurological performance. Western blot was conducted to evaluate the level of GSDMD-N. ELISA kits were used to measure the levels of IL-1β and IL-18. qRT-PCR and Western blot were performed to evaluate the expressions of NLRP3 inflammasome, IL-1β, and IL-18.

RESULTS

The expression of Dectin-1 increased following ICH, and Dectin-1 was expressed on microglia. In addition, inhibition of Dectin-1 by laminarin decreased brain edema and neurological impairment after ICH. Moreover, inhibition of Dectin-1 decreased the expression of pyroptosis-related protein, GSDMD-N, and inflammatory cytokines (IL-1β and IL-18). Mechanistically, Dectin-1 blockade inhibits NLRP3 inflammasome activation, thereby alleviating neuroinflammatory injury by attenuating NLRP3 inflammasome-mediated pyroptosis both in vivo and in vitro.

CONCLUSION

Our study indicates that the inhibition of Dectin-1 alleviates neuroinflammation by attenuating NLRP3 inflammasome-mediated pyroptosis after ICH.

Serum concentrations of NLRP3 in relation to functional outcome and delayed cerebral ischemia after aneurysmal subarachnoid hemorrhage

BACKGROUND

Nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing 3 (NLRP3) participates in neuroinflammation. We endeavored to determine the role of serum NLRP3 as a biomarker of neuroinflammation, severity, delayed cerebral ischemia (DCI) and functional outcome following aneurysmal subarachnoid hemorrhage (aSAH).

METHODS

In this prospective and observational study, a total of 118 aSAH patients and 118 healthy volunteers were enrolled. Serum NLRP3 concentrations, blood glucose concentrations, serum C-reactive protein concentrations, and blood leucocyte counts were quantified. A poor outcome was defined as extended Glasgow outcome scale scores of 1-4 at post-injury 90 days.

RESULTS

As compared to controls, significantly increased serum NLRP3 concentrations after aSAH were intimately correlated with the Glasgow coma scale scores, World Federation of Neurological Surgeons scale scores, Hunt-Hess scores, modified Fisher scores, extended Glasgow outcome scale scores, blood glucose concentrations, serum C-reactive protein concentrations and blood leucocyte counts. Serum NLRP3 emerged as an independent predictor for DCI and poor 90-day outcome. Using receiver operating characteristic curve, serum NLRP3 concentrations were significantly predictive of DCI and poor 90-day outcome. Its prognostic predictive ability was comparable to those of the Glasgow coma scale scores, World Federation of Neurological Surgeons scale scores, Hunt-Hess scores and modified Fisher scores.

CONCLUSIONS

Serum NLRP3 may represent an inflammatory biomarker in relation to the severity, DCI and poor functional outcome after aSAH.

Emerging trends and hot spots of NLRP3 inflammasome in neurological diseases: A bibliometric analysis

Background: NLRP3 inflammasome has been of great interest in the field of neurological diseases. To visualize the research hotspots and evolutionary trends in this area, we collected the relevant articles in the Web of Science Core Collection database from 2010 to 2022 and analyzed them using CiteSpace software.

Methods: We performed a systematic search of the literature within the Web of Science Core Collection database using the strategy described below: TS = NLRP3 inflammasome AND TS = neurological diseases OR TS = neurological disorder OR TS = brain disorder OR TS = brain injury OR TS = central nervous system disease OR TS = CNS disease OR TS = central nervous system disorder OR TS = CNS disorder AND Language = English from 2010 to 2022. The type of literature was limited to articles and reviews. The data were processed using CiteSpace software (version 5.8. R3).

Results: A total of 1,217 literature from 67 countries/regions and 337 research institutions was retrieved. Publications in this area have increased rapidly since 2013. China presents the highest number of published articles, but the United States has a higher centrality and h-index. The top five most published institutions and authors are from China, Zhejiang University and Li Y ranking first, respectively. Of the ten most cited articles, Prof. Heneka MT and colleagues accounted for three of them. In terms of the co-occurrence keyword diagram, the five most frequent keywords are “nlrp3 inflammasome”, “activation”, “oxidative stress”, “expression”, and “alzheimers disease”.

Conclusion: The research of NLRP3 inflammasome in neurological disorders is overall developing well. Chinese scholars contributed the most significant number of articles, while researchers from developed countries presented more influential papers. The importance of NLRP3 inflammasome in neurological diseases is widely appreciated, and the mechanism is under study. Moreover, NLRP3 inflammasome is emerging as a promising therapeutic target in treating neurological disorders. However, despite decades of research, our understanding of NLRP3 inflammasome in central nervous system diseases is still lacking. More and more profound research is needed in the future.

Prolonged increased neutrophil-to-lymphocyte ratio is associated with mortality after successful revascularization for treatment of acute ischemic stroke

Background

To determine the association between dynamic neutrophil-to-lymphocyte ratio (NLR) during hospitalization and mortality 1 month after ischemia reperfusion in patients undergoing endovascular treatment (EVT) with successful revascularization for acute large vessel occlusion stroke.

Methods

This retrospective study included patients who had undergone successful EVT. Information was collected regarding patients’ clinical characteristics, imaging data, and mortality at 1 month. Univariate and multivariate logistic regression models were applied to assess the association between NLR and mortality. We used a generalized additive model and a generalized additive mixed model to compare trends in NLR over time between survivors and nonsurvivors.

Results

A total of 237 patients were included. During the 1-month follow-up, 42 of these patients (17.7%) died. The multivariate analysis demonstrated that NLR obtained within 12 to 24 hours (odds ratio [OR] = 1.18; 95% confidence interval [CI]: 1.04, 1.33; P = 0.008), 24 to 48 hours (OR = 1.16; 95% CI: 1.01, 1.35; P = 0.044), and 48 to 72 hours (OR = 1.23; 95% CI: 1.03, 1.47; P = 0.021) after EVT were independently associated with mortality at 1 month. In addition, there was a trend for NLR to decrease gradually over time for both survivors and nonsurvivors; however, NLR in survivors decreased by an average of 0.29 daily than in nonsurvivors.

Conclusions

Increased NLR in the early period after EVT was associated with an increased risk of mortality, and a continued trend toward higher NLR over time was also linked with a higher mortality risk.

Rhodiola crenulate alleviates hypobaric hypoxia-induced brain injury via adjusting NF-κB/NLRP3-mediated inflammation

BACKGROUND

Rhodiola crenulate (R. crenulate), a famous Tibetan medicine, has been demonstrated to possess superiorly protective effects in high-altitude hypoxic brain injury (HHBI). However, its mechanisms on HHBI are still largely unknown.

METHODS

Herein, the protective effects and underlying mechanisms of R. crenulate on HHBI of BABL/c mice were explored through in vivo experiments. The mice model of HHBI was established using an animal hypobaric and hypoxic chamber. R. crenulate extract (RCE) (0.5, 1.0 and 2.0 g/kg) was given by gavage for 7 days. Pathological changes and neuronal viability of mice hippocampus and cortex were evaluated using H&E and Nissl staining, respectively. The brain water content (BWC) in mice was determined by calculating the ratio of dry to wet weight of brain tissue. And serum of malondialdehyde (MDA), superoxide dismutase (SOD), glutathione (GSH-Px) and lactate dehydrogenase (LDH) were detected via commercial biochemical kits. Synchronously, the contents of total antioxidant capacity (T-AOC), lactic acid (LA), adenosine triphosphate (ATP), succinate dehydrogenase (SDH), pyruvate kinase (PK), Ca²⁺-Mg²⁺-ATPcase, Na⁺-K⁺-ATPcase, TNF-α, IL-1β and IL-6 in brain tissue were quantitative analysis by corresponding ELISA assay. Subsequently, NLRP3, ZO-1, claudin-5, occluding, p-p65, p65, ASC, cleaved-caspase-1, caspase-1 and IL-18 were determined by immunofluorescent and western blot analyses.

RESULTS

The results demonstrated that RCE remarkably alleviated pathological damage, BWC, as well enhanced neuronal viability. Furthermore, the oxidative stress injuries were reversely abrogated after RCE treatment, evidenced by the increases of SOD, GSH-Px and T-AOC, while the decreases of MDA and LDH contents. Marvelously, the administration of RCE rectified and balanced the abnormal energy metabolism via elevating the levels of ATP, SDH, PK, Ca²⁺-Mg²⁺-ATPcase and Na⁺-K⁺-ATPcase, and lowering LA. Simultaneously, the expression of tight junction proteins (ZO-1, claudin-5 and occludin) was enhanced, illustrating RCE treatment might maintain the integrity of blood-brain barrier (BBB). Additionally, RCE treatment confined the contents of IL-6, IL-1β and TNF-α, and attenuated fluorescent signal of NLRP3 protein. Concurrently, the results of western blot indicated that RCE treatment dramatically restrained p-p65/p65, ASC, NLRP3, cleaved-caspase-1/caspase-1 and IL-18 protein expressions in brain tissues of mice.

CONCLUSION

RCE may afford a protectively intervention in HHBI of mice through suppressing the oxidative stress, improving energy metabolism and the integrity of BBB, and subsiding inflammatory responses via the NF-κB/NLRP3 signaling pathway. As a promising agent for the treatment of mice HHBI, the deep-crossing molecular mechanisms of R. crenulate still needs to be further elucidated to identify novel core hub targets.

Parthenolide ameliorates neurological deficits and neuroinflammation in mice with traumatic brain injury by suppressing STAT3/NF-κB and inflammasome activation

BACKGROUND

Traumatic brain injury (TBI) triggers a set of complex inflammation that results in secondary injury. Parthenolide (PTN) is a sesquiterpene lactone extracted from the herb Tanacetum parthenium (Feverfew) and has potent anti-inflammatory, anti-apoptosis and anti-oxidative stress effects in the central nervous system (CNS)-related diseases. This study focuses on investigating the potential neuroprotective effect of PTN on TBI and the related mechanism.

METHODS

Bv2 microglia, primary microglia were stimulated by LPS, and HT22 neuron cells were stimulated by OGD/R, and they were treated with different doses of PTN. The expression profiles of pro-inflammatory cytokines, proteins, oxidative stress mediators, STAT3/NF-κB pathway, inflammasomes were detected. Forty male/female C57BL/6 mice were randomly divided into the sham, PTN, TBI, and TBI + PTN groups (10 mice per group). A mouse TBI model was set up with a controlled cortical impact (CCI) device. The modified nerve severity score (mNSS) was implemented to check short-term neurological impairment in mice, and the mice's memory and learning were assessed by the Morris water maze test. The water content in the mice's brains was measured by the dry-wet method. Hematoxylin-eosin (H&E) staining, Nissl staining and terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL) assay were applied for neuronal apoptosis.

RESULTS

PTN dramatically alleviated LPS-induced inflammation in microglia, and OGD-mediated neuronal apoptosis and oxidative stress. In addition, PTN repressed LPS- or OGD-modulated STAT3/NF-κB and NLR family pyrin domain containing 1 (NLRP1), NLRP3, NLR family CARD domain containing 4 (NLRC4) inflammasomes activation. Administering the STAT3 inhibitor Stattic or NF-κB inhibitor Bay 11-7082 attenuated PTN-mediated effects. In vivo, PTN treatment relieved neural function deficits, brain edema and neuron apoptosis and improved the memory and learning function of TBI mice. Additionally, PTN impeded microglial activation and reduced the production of pro-inflammatory cytokines in brain lesions of TBI mice. Furthermore, PTN hindered STAT3/NF-κB and inflammasome activation.

CONCLUSION

PTN can curb microglial activation and neuron apoptosis by dampening the STAT3/NF-κB pathway, thus exerting neuroprotective effects in TBI mice.

Erythropoietin Enhances Post-ischemic Migration and Phagocytosis and Alleviates the Activation of Inflammasomes in Human Microglial Cells

Recombinant human erythropoietin (rhEPO) has been shown to exert anti-apoptotic and anti-inflammatory effects after cerebral ischemia. Inflammatory cytokines interleukin-1β and -18 (IL-1β and IL-18) are crucial mediators of apoptosis and are maturated by multiprotein complexes termed inflammasomes. Microglia are the first responders to post-ischemic brain damage and are a main source of inflammasomes. However, the impact of rhEPO on microglial activation and the subsequent induction of inflammasomes after ischemia remains elusive. To address this, we subjected human microglial clone 3 (HMC-3) cells to various durations of oxygen-glucose-deprivation/reperfusion (OGD/R) to assess the impact of rhEPO on cell viability, metabolic activity, oxidative stress, phagocytosis, migration, as well as on the regulation and activation of the NLRP1, NLRP3, NLRC4, and AIM2 inflammasomes. Administration of rhEPO mitigated OGD/R-induced oxidative stress and cell death. Additionally, it enhanced metabolic activity, migration and phagocytosis of HMC-3. Moreover, rhEPO attenuated post-ischemic activation and regulation of the NLRP1, NLRP3, NLRC4, and AIM2 inflammasomes as well as their downstream effectors CASPASE1 and IL-1β. Pharmacological inhibition of NLRP3 via MCC950 had no effect on the activation of CASPASE1 and maturation of IL-1β after OGD/R, but increased protein levels of NLRP1, NLRC4, and AIM2, suggesting compensatory activities among inflammasomes. We provide evidence that EPO-conveyed anti-inflammatory actions might be mediated via the regulation of the inflammasomes.

Targeting NLRP3 inflammasome modulates gut microbiota, attenuates corticospinal tract injury and ameliorates neurobehavioral deficits after intracerebral hemorrhage in mice

Intracerebral hemorrhage (ICH) has a high mortality and disability rate. Fewer studies focus on white matter injury (WMI) after ICH, especially the corticospinal tract (CST) injury located in the spinal cord, which correlates with motor impairments. Recent studies have shown that gut microbiota dysbiosis occurs after ICH. Furthermore, NLRP3 inflammasome can be activated after ICH, resulting in inflammatory cascade reactions and aggravating brain injury. However, no direct and causal correlation among NLRP3 inflammasome inhibition, altered gut microbiota, and CST injury following ICH has been reported. This study aimed to investigate the effect of MCC950, a selective NLRP3 inflammasome inhibitor, on the gut microbiota and CST injury after ICH. We observed that compared with the sham group, the members of Firmicutes, such as Faecalibaculum and Dubosiella, were depleted in the ICH + Vehicle group, whereas the members of Proteobacteria and Campilobacterota were enriched, such as Enterobacter and Helicobacter. After treatment with MCC950, the Bacteroides, Bifidobacterium and Paenibacillus were relatively abundant in the gut flora of mice. Moreover, we observed CST injury located in cervical enlargement of the spinal cord, and MCC950 alleviated it. Furthermore, treatment with MCC950 decreased the mNSS score and brain water content in ICH. Taken together, the present study showed that MCC950 modulated gut microbiota, effectively attenuated CST injury located in cervical enlargement of the spinal cord, and ameliorated neurological deficits after ICH. This study provided a novel report that links NLRP3 inflammasome inhibition, gut microbiota alteration and CST injury following ICH and profound implications for ICH treatment.

Neuroinflammation Associated With Inborn Errors of Immunity

The advent of high-throughput sequencing has facilitated genotype-phenotype correlations in congenital diseases. This has provided molecular diagnosis and benefited patient management but has also revealed substantial phenotypic heterogeneity. Although distinct neuroinflammatory diseases are scarce among the several thousands of established congenital diseases, elements of neuroinflammation are increasingly recognized in a substantial proportion of inborn errors of immunity, where it may even dominate the clinical picture at initial presentation. Although each disease entity is rare, they collectively can constitute a significant proportion of neuropediatric patients in tertiary care and may occasionally also explain adult neurology patients. We focus this review on the signs and symptoms of neuroinflammation that have been reported in association with established pathogenic variants in immune genes and suggest the following subdivision based on proposed underlying mechanisms: autoinflammatory disorders, tolerance defects, and immunodeficiency disorders. The large group of autoinflammatory disorders is further subdivided into IL-1β-mediated disorders, NF-κB dysregulation, type I interferonopathies, and hemophagocytic syndromes. We delineate emerging pathogenic themes underlying neuroinflammation in monogenic diseases and describe the breadth of the clinical spectrum to support decisions to screen for a genetic diagnosis and encourage further research on a neglected phenomenon.

Caffeine treatment started before injury reduces hypoxic-ischemic white-matter damage in neonatal rats by regulating phenotypic microglia polarization

BACKGROUND

Reducing neuroinflammatory damage is an effective strategy for treating white-matter damage (WMD) in premature infants. Caffeine can ameliorate hypoxia-ischemia-induced brain WMD; however, its neuroprotective effect and mechanism against hypoxic-ischemic WMD remain unclear.

METHODS

We used 3-day-old Sprague-Dawley rats to establish a model of cerebral hypoxia-ischemia-induced brain WMD after unilateral common carotid artery ligation and hypoxia exposure (8% O₂ + 92% N₂) for 2.5 h. Mechanism experiments were conducted to detect M1/M2 polarization and activation of microglia and NLRP3 inflammasome.

RESULTS

Caffeine inhibited NLRP3 inflammasome activation, reduced microglial Iba-1 activation, inhibited microglia M1 polarization, and promoted microglia M2 polarization by downregulating CD86 and iNOS protein expression, inhibiting the transcription of the proinflammatory TNF-α and IL-1β, upregulating CD206 and Arg-1 expression, and promoting the transcription of the anti-inflammatory factors IL-10 and TGF-β. Importantly, we found that these caffeine-mediated effects could be reversed after inhibiting A2aR activity.

CONCLUSIONS

Caffeine improved long-term cognitive function in neonatal rats with hypoxic-ischemic WMD via A2aR-mediated inhibition of NLRP3 inflammasome activation, reduction of microglial activation, regulation of the phenotypic polarization of microglia and the release of inflammatory factors, and improvement of myelination development.

IMPACT

The direct protective effect of caffeine on hypoxic-ischemic white-matter damage (WMD) and its mechanism remains unclear. This study elucidated this mechanism using neonatal rats as an animal model of hypoxia-ischemia-induced cerebral WMD. The findings demonstrated caffeine as a promising therapeutic tool against immature WMD to protect neonatal cognitive function. We found that caffeine pretreatment reduced WMD in immature brains via regulation of microglial activation and polarization by adenosine A2a receptor, thereby, providing a scientific basis for future clinical application of caffeine.

Biological Functions and Regulatory Mechanisms of Hypoxia-Inducible Factor-1α in Ischemic Stroke

Ischemic stroke is caused by insufficient cerebrovascular blood and oxygen supply. It is a major contributor to death or disability worldwide and has become a heavy societal and clinical burden. To date, effective treatments for ischemic stroke are limited, and innovative therapeutic methods are urgently needed. Hypoxia inducible factor-1α (HIF-1α) is a sensitive regulator of oxygen homeostasis, and its expression is rapidly induced after hypoxia/ischemia. It plays an extensive role in the pathophysiology of stroke, including neuronal survival, neuroinflammation, angiogenesis, glucose metabolism, and blood brain barrier regulation. In addition, the spatiotemporal expression profile of HIF-1α in the brain shifts with the progression of ischemic stroke; this has led to contradictory findings regarding its function in previous studies. Therefore, unveiling the Janus face of HIF-1α and its target genes in different type of cells and exploring the role of HIF-1α in inflammatory responses after ischemia is of great importance for revealing the pathogenesis and identifying new therapeutic targets for ischemic stroke. Herein, we provide a succinct overview of the current approaches targeting HIF-1α and summarize novel findings concerning HIF-1α regulation in different types of cells within neurovascular units, including neurons, endothelial cells, astrocytes, and microglia, during the different stages of ischemic stroke. The current representative translational approaches focused on neuroprotection by targeting HIF-1α are also discussed.

Microglia in the Pathophysiology of Hemorrhagic Stroke and the Relationship Between Microglia and Pain After Stroke: A Narrative Review

Stroke is a leading cause of death worldwide, and about a quarter of stroke patients are dead within 1 month. The prognosis is even worse for those with hemorrhagic stroke because the 1-month mortality approaches 50%. Besides, most patients who survive experience complications such as nausea, vomiting, and chronic pain. These adverse experiences, especially the existence of chronic pain, can lead to a decline in the patient's quality of life. In order to improve the treatment and prognosis of hemorrhagic stroke, there is an urgent need to understand its pathophysiological mechanism as well as the chronic pain it induces. This paper reviews studies of the molecular mechanisms of hemorrhagic stroke, especially the activation of microglia and the relationship between microglia and pain after stroke, which could shed new light on hemorrhagic stroke treatment.

CCR5 Activation Promotes NLRP1-Dependent Neuronal Pyroptosis via CCR5/PKA/CREB Pathway After Intracerebral Hemorrhage

Supplemental Digital Content is available in the text.

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).

Microglia Phenotype and Intracerebral Hemorrhage: A Balance of Yin and Yang

Intracerebral hemorrhage (ICH) features extremely high rates of morbidity and mortality, with no specific and effective therapy. And local inflammation caused by the over-activated immune cells seriously damages the recovery of neurological function after ICH. Fortunately, immune intervention to microglia has provided new methods and ideas for ICH treatment. Microglia, as the resident immune cells in the brain, play vital roles in both tissue damage and repair processes after ICH. The perihematomal activated microglia not only arouse acute inflammatory responses, oxidative stress, excitotoxicity, and cytotoxicity to cause neuron death, but also show another phenotype that inhibit inflammation, clear hematoma and promote tissue regeneration. The proportion of microglia phenotypes determines the progression of brain tissue damage or repair after ICH. Therefore, microglia may be a promising and imperative therapeutic target for ICH. In this review, we discuss the dual functions of microglia in the brain after an ICH from immunological perspective, elaborate on the activation mechanism of perihematomal microglia, and summarize related therapeutic drugs researches.

Bioinformatics Identification of Ferroptosis-Related Biomarkers and Therapeutic Compounds in Ischemic Stroke

Background: Stroke is one of the most common deadly diseases with an estimated 780,000 new cases globally, of which ischemic stroke accounts for over 80% of all cases. Ferroptosis is a new form of programmed cell death that plays a vital role in many diseases, including ischemic stroke and heart diseases. The role of the ferroptosis-related gene in the diagnosis, prognosis, or therapy of ischemic stroke was not fully clarified.

Methods: Ferroptosis-related differentially expressed genes (DEGs) in ischemic stroke were identified by bioinformatic analysis of the GSE16561 and GSE22255 datasets. Subsequently, receiver operator characteristic (ROC) monofactor analysis was performed to evaluate the diagnostic value of ferroptosis-related biomarkers in ischemic stroke.

Results: A total of 10 ferroptosis-related DEGs were identified in ischemic stroke vs. normal control. GO and KEGG analysis revealed that these 10 ferroptosis-related DEGs were mainly enriched in response to oxidative stress, HIF-1 signaling pathway, ferroptosis, lipid, and atherosclerosis. Moreover, the random forest model suggested three ferroptosis-related biomarkers, namely, PTGS2, MAP1LC3B, and TLR4, for ischemic stroke. Interestingly, the expression of PTGS2, MAP1LC3B, and TLR4 was upregulated in ischemic stroke. ROC monofactor analysis demonstrated a good performance of MAP1LC3B, PTGS2, and TLR4 in the diagnosis of ischemic stroke. The expression and diagnostic value of MAP1LC3B, PTGS2, and TLR4 in ischemic stroke were also verified using GSE22255. We also revealed the transcription factor regulation network and co-expressed protein network of ferroptosis-related biomarkers. Several potential therapeutic compounds corresponding to MAP1LC3B, PTGS2, and TLR4 were also identified for ischemic stroke, including Zinc12503187 (Conivaptan), Zinc3932831 (Avodart), Zinc64033452 (Lumacaftor), Zinc11679756 (Eltrombopag), Zinc100378061 (Naldemedine), and Zinc3978005 (Dihydroergotamine).

Conclusion: Our results suggested MAP1LC3B, PTGS2, and TLR4 as potential diagnostic biomarkers for ischemic stroke, providing more evidence about the vital role of ferroptosis in ischemic stroke.

NLRP3 inhibition attenuates early brain injury and delayed cerebral vasospasm after subarachnoid hemorrhage

BACKGROUND

The NLRP3 inflammasome is a critical mediator of several vascular diseases through positive regulation of proinflammatory pathways. In this study, we defined the role of NLRP3 in both the acute and delayed phases following subarachnoid hemorrhage (SAH). SAH is associated with devastating early brain injury (EBI) in the acute phase, and those that survive remain at risk for developing delayed cerebral ischemia (DCI) due to cerebral vasospasm. Current therapies are not effective in preventing the morbidity and mortality associated with EBI and DCI. NLRP3 activation is known to drive IL-1β production and stimulate microglia reactivity, both hallmarks of SAH pathology; thus, we hypothesized that inhibition of NLRP3 could alleviate SAH-induced vascular dysfunction and functional deficits.

METHODS

We studied NLRP3 in an anterior circulation autologous blood injection model of SAH in mice. Mice were randomized to either sham surgery + vehicle, SAH + vehicle, or SAH + MCC950 (a selective NLRP3 inhibitor). The acute phase was studied at 1 day post-SAH and delayed phase at 5 days post-SAH.

RESULTS

NLRP3 inhibition improved outcomes at both 1 and 5 days post-SAH. In the acute (1 day post-SAH) phase, NLRP3 inhibition attenuated cerebral edema, tight junction disruption, microthrombosis, and microglial reactive morphology shift. Further, we observed a decrease in apoptosis of neurons in mice treated with MCC950. NLRP3 inhibition also prevented middle cerebral artery vasospasm in the delayed (5 days post-SAH) phase and blunted SAH-induced sensorimotor deficits.

CONCLUSIONS

We demonstrate a novel association between NLRP3-mediated neuroinflammation and cerebrovascular dysfunction in both the early and delayed phases after SAH. MCC950 and other NLRP3 inhibitors could be promising tools in the development of therapeutics for EBI and DCI.

Targeting Inflammasomes to Treat Neurological Diseases

Inflammasomes are multimeric protein complexes that can sense a plethora of microbe- and damage-associated molecular signals. They play important roles in innate immunity and are key regulators of inflammation in health and disease. Inflammasome-mediated processing and secretion of proinflammatory cytokines such as interleukin (IL) 1β and IL-18 and induction of pyroptosis, a proinflammatory form of cell death, have been associated with the development and progression of common immune-mediated and degenerative central nervous system (CNS) diseases such as Alzheimer disease, multiple sclerosis, brain injury, stroke, epilepsy, Parkinson disease, and amyotrophic lateral sclerosis. A growing number of pharmacological compounds inhibiting inflammasome activation and signaling show therapeutic efficacy in preclinical models of the aforementioned disease conditions. Here, we illustrate regulatory mechanisms of inflammasome activation during CNS homeostasis and tissue injury. We highlight the evidence for inflammasome activation as a mechanistic underpinning in a wide range of CNS diseases and critically discuss the promise and potential limitations of therapeutic strategies that aim to inhibit the inflammasome components in neurological disorders. ANN NEUROL 2021;90:177-188.

Neferine Protects against Hypoxic-Ischemic Brain Damage in Neonatal Rats by Suppressing NLRP3-Mediated Inflammasome Activation

Hypoxic-ischemic encephalopathy (HIE) is recognized as the main cause of neonatal death, and efficient treatment strategies remain limited. Given the prevalence of HIE and the associated fatality, further studies on its pathogenesis are warranted. Oxidative stress and neuroinflammatory injury are two important factors leading to brain tissue injury and nerve cell loss in HIE. Neferine, an alkaloid extracted from lotus seed embryo, exerts considerable effects against several diseases such as cancers and myocardial injury. In this study, we demonstrated the neuroprotective effect of neferine on HIE and hypothesized that it involves the inhibition of neuronal pyroptosis, thereby ameliorating neurological inflammation and oxidative stress. We demonstrated that the mRNA levels of proteins associated with pyroptosis including caspase-1, the caspase adaptor ASC, gasdermin D, interleukin- (IL-) 18, IL-1β, and some inflammatory factors were significantly increased in neonatal HIBD model rats compared to those in the control group. The increase in these factors was significantly suppressed by treatment with neferine. We stimulated PC12 cells with CoCl₂ to induce neuronal HIBD in vitro and investigated the relationship between neferine and pyroptosis by altering the expression of the NLRP3 inflammasome. The overexpression of NLRP3 partially reversed the neuroprotective effect of neferine on HIBD, whereas NLRP3 knockdown further inhibited caspase-1 activation and IL-1β and IL18 expression. In addition, simultaneous alteration of NLRP3 expression induced changes in intracellular oxidative stress levels after HIBD. These findings indicate that neferine ameliorates neuroinflammation and oxidative stress injury by inhibiting pyroptosis after HIBD. Our study provides valuable information for future studies on neferine with respect to neuroinflammation and pyroptosis.

Pyroptosis in stroke-new insights into disease mechanisms and therapeutic strategies

Stroke is a common disease with high mortality and disability worldwide. Different forms of cell deaths, including apoptosis and necrosis, occur in ischemic or hemorrhagic brain tissue, among which pyroptosis, a newly discovered inflammation-related programmed cell death, is generally divided into two main pathways, the canonical inflammasome pathway and the non-canonical inflammasome pathway. Caspase-mediated pyroptosis requires the assembly of inflammasomes such as NLRP3, which leads to the release of inflammatory cytokines IL-1β and IL-18 through the pores formed in the plasma membrane by GSDMD followed by neuroinflammation. Recently, pyroptosis and its relationship with inflammation have attracted more and more attention in the study of cerebral ischemia or hemorrhage. In addition, many inhibitors of pyroptosis targeting caspase, NLRP3, and the upstream pathway have been found to reduce brain tissue damage after stroke. In this review, we mainly introduce the pathology of stroke, the molecular mechanism, and process of pyroptosis, as well as the pivotal roles of pyroptosis in stroke, in order to provide new insights for the treatment of stroke.

INT-777 attenuates NLRP3-ASC inflammasome-mediated neuroinflammation via TGR5/cAMP/PKA signaling pathway after subarachnoid hemorrhage in rats

BACKGROUND

Inflammasome-mediated neuroinflammation plays an important role in the pathogenesis of early brain injury (EBI) following subarachnoid hemorrhage (SAH). The activation of the TGR5 receptor has been shown to be neuroprotective in a variety of neurological diseases. This study aimed to investigate the effects of the specific synthetic TGR5 agonist, INT-777, in attenuating NLRP3-ASC inflammasome activation and reducing neuroinflammation after SAH.

METHODS

One hundred and eighty-four male Sprague Dawley rats were used. SAH was induced by the endovascular perforation. INT-777 was administered intranasally at 1 h after SAH induction. To elucidate the signaling pathway involved in the effect of INT-777 on inflammasome activation during EBI, TGR5 knockout CRISPR and PKA inhibitor H89 were administered intracerebroventricularly and intraperitoneally at 48 h and 1 h before SAH. The SAH grade, short- and long-term neurobehavioral assessments, brain water content, western blot, immunofluorescence staining, and Nissl staining were performed.

RESULTS

The expressions of endogenous TGR5, p-PKA, and NLRP3-ASC inflammasome were increased after SAH. INT-777 administration significantly decreased NLRP3-ASC inflammasome activation in microglia, reduced brain edema and neuroinflammation, leading to improved short-term neurobehavioral functions at 24 h after SAH. The administration of TGR5 CRISPR or PKA inhibitor (H89) abolished the anti-inflammation effects of INT-777, on NLRP3-ASC inflammasome, pro-inflammatory cytokines (IL-6, IL-1β, and TNF-a), and neutrophil infiltration at 24 h after SAH. Moreover, early administration of INT-777 attenuated neuronal degeneration in hippocampus on 28 d after SAH.

CONCLUSIONS

INT-777 attenuated NLRP3-ASC inflammasome-dependent neuroinflammation in the EBI after SAH, partially via TGR5/cAMP/PKA signaling pathway. Early administration of INT-777 may serve as a potential therapeutic strategy for EBI management in the setting of SAH.