Inhibition of caspase-1-mediated inflammasome activation reduced blood coagulation in cerebrospinal fluid after subarachnoid haemorrhage

Cav3.2 channel regulates cerebral ischemia/reperfusion injury: a promising target for intervention

JOURNAL/nrgr/04.03/01300535-202419110-00028/figure1/v/2024-03-08T184507Z/r/image-tiff Calcium influx into neurons triggers neuronal death during cerebral ischemia/reperfusion injury. Various calcium channels are involved in cerebral ischemia/reperfusion injury. Cav3.2 channel is a main subtype of T-type calcium channels. T-type calcium channel blockers, such as pimozide and mibefradil, have been shown to prevent cerebral ischemia/reperfusion injury-induced brain injury. However, the role of Cav3.2 channels in cerebral ischemia/reperfusion injury remains unclear. Here, in vitro and in vivo models of cerebral ischemia/reperfusion injury were established using middle cerebral artery occlusion in mice and high glucose hypoxia/reoxygenation exposure in primary hippocampal neurons. The results showed that Cav3.2 expression was significantly upregulated in injured hippocampal tissue and primary hippocampal neurons. We further established a Cav3.2 gene-knockout mouse model of cerebral ischemia/reperfusion injury. Cav3.2 knockout markedly reduced infarct volume and brain water content, and alleviated neurological dysfunction after cerebral ischemia/reperfusion injury. Additionally, Cav3.2 knockout attenuated cerebral ischemia/reperfusion injury-induced oxidative stress, inflammatory response, and neuronal apoptosis. In the hippocampus of Cav3.2-knockout mice, calcineurin overexpression offset the beneficial effect of Cav3.2 knockout after cerebral ischemia/reperfusion injury. These findings suggest that the neuroprotective function of Cav3.2 knockout is mediated by calcineurin/nuclear factor of activated T cells 3 signaling. Findings from this study suggest that Cav3.2 could be a promising target for treatment of cerebral ischemia/reperfusion injury.

Hepcidin depending on astrocytic NEO1 ameliorates blood-brain barrier dysfunction after subarachnoid hemorrhage

Subarachnoid hemorrhage (SAH) significantly compromises the blood-brain barrier (BBB) and impairs patient recovery. This study elucidates the critical role of astrocytic Neogenin-1 (NEO1) in BBB integrity post-SAH and examines the regulatory effects of hepcidin on endothelial cell (EC) function amid NEO1-mediated disruptions in iron homeostasis. Proteomic analyses of cerebrospinal fluid (CSF) from SAH patients revealed a substantial decrease in NEO1 expression, identifying it as a key factor in BBB integrity. 111 CSF proteins were significantly reduced in early SAH stages (days 1-3), with NEO1 among the most significantly altered. This dysregulation was linked to poorer patient outcomes, as indicated by a negative correlation between NEO1 levels and Modified Rankin Scale scores six months post-SAH (R = -0.4743, P < 0.0001). Experimental models further highlighted the importance of NEO1: SAH model and NEO1GFAP-Cre mice exhibited exacerbated EC dysfunction and increased BBB permeability, evidenced by significant Evans Blue retention and dextran leakage in the parietal cortex, effects that were mitigated by hepcidin administration. Our findings highlight the complex interplay between astrocytic signaling and endothelial function in SAH pathophysiology. The loss of astrocytic NEO1 led to increased EC proliferation and altered BBB structure, as confirmed by transmission electron microscopy and immunostaining for PECAM-1, indicating heightened blood vessel density in the affected cortex. Hepcidin treatment effectively reversed the EC dysfunction and BBB disruption in both NEO1-cKO mice and the SAH model, highlighting its potential as a therapeutic agent to enhance recovery and improve prognosis following SAH.

Increased serum caspase-1 in adult-onset Still's disease

BACKGROUND

Caspase-1 is a crucial component in the inflammasome activation cascade. This study evaluated the potential of serum caspase-1 level as an inflammatory biomarker in patients with adult-onset Still's disease (AOSD).

METHODS

The study included 51 consecutive patients diagnosed with AOSD based on the Yamaguchi criteria, 66 patients with rheumatoid arthritis (RA) as disease control, and 36 healthy controls (HCs). Serum caspase-1 concentrations were measured using enzyme-linked immunosorbent assay. The serum 69 cytokine levels were analyzed using a multisuspension cytokine array in patients with AOSD, and a cluster analysis of each cytokine was performed to determine specific molecular networks.

RESULTS

Patients with AOSD had significantly increased serum caspase-1 levels versus patients with RA (p < 0.001) and HCs (p < 0.001). Additionally, serum caspase-1 demonstrated significant positive correlations with AOSD disease activity score (Pouchot score, r = 0.59, p < 0.001) and serum ferritin (r = 0.54, p < 0.001). Furthermore, among patients with AOSD, significant correlations existed between serum caspase-1 and inflammatory cytokines, including interleukin-18. Immunoblot analysis detected the cleaved form of caspase-1 (p20) in the serum of untreated patients with AOSD, not in those from patients with inactive AOSD receiving immunosuppressive treatments.

CONCLUSIONS

Caspase-1 is a useful biomarker for AOSD diagnosis and monitoring. Caspase-1 activation could be correlated with the inflammatory component of AOSD, specifically through proinflammatory cytokine induction via inflammasome activation cascades.

Selective Activation of G Protein-Coupled Estrogen Receptor 1 (GPER1) Reduces ER Stress and Pyroptosis via AMPK Signaling Pathway in Experimental Subarachnoid Hemorrhage

Neuroinflammation is a critical pathogenic event following hemorrhagic stroke. Endoplasmic reticulum (ER) stress-induced apoptosis and nucleotide-binding domain, leucine-rich repeat, and pyrin domain-containing protein 3(NLRP3)-associated pyroptosis can contribute to the escalation of neuroinflammatory responses, leading to increased brain damage. G protein-coupled estrogen receptor 1(GPER1), as the most extensively characterized brain-derived estrogen, was reported to trigger neuroprotective effects. However, the anti-apoptotic and anti-pyroptotic effect of GPER1 activation and the underlying mechanism has not been fully elucidated. We established the experimental SAH model by intravascular perforation. The GPER1 selective agonist G1 was intravenously administered 1 h following SAH. For mechanistic exploration, the selective inhibitor of adenosine monophosphate-activated protein kinase (AMPK), dorsomorphin, was administered via intracerebroventricular injection 30 min prior to SAH induction. Post-SAH assessments included SAH grade, the short-term and long-term neurological outcomes, brain edema, cerebral blood flow, transmission electron microscopy (TEM), western blot (WB), ELISA, TUNEL staining, Fluoro-Jade C staining (FJC), and immunofluorescence staining. The expression of GPER1 was observed to elevate at 6 h and peaked at 24 h subsequent to SAH, predominantly co-localized with neurons. Post-treatment with G1 markedly ameliorated both the short-term and long-term neurological deficits of SAH mouse, as well as inhibiting the expression of neuronal ER stress-associated apoptotic proteins (i.e., CHOP, GRP78, Caspase-12, Cleaved Caspase-3, Bax, Bcl2) and pyroptosis-associated proteins (i.e., NLRP3, ASC, Cleaved Caspase-1). Additionally, our research revealed that inhibition of AMPK with dorsomorphin attenuated the neuroprotective effects of G1. This was accompanied by modifications in the molecular pathways associated with ER stress-induced apoptosis and pyroptosis. These data herein elucidated that GPER1 exerted neuroprotective effects by mitigating neuroinflammation in an AMPK-dependent manner, which modulates neuronal ER stress-associated apoptosis and pyroptosis. Boosting the anti-apoptotic and anti-pyroptotic effect by activating GPER1 may be an efficient treatment strategy for SAH patients.

Potential convergence of olfactory dysfunction in Parkinson's disease and COVID-19: The role of neuroinflammation

Parkinson's disease (PD) is a prevalent neurodegenerative disorder that affects 7-10 million individuals worldwide. A common early symptom of PD is olfactory dysfunction (OD), and more than 90% of PD patients suffer from OD. Recent studies have highlighted a high incidence of OD in patients with SARS-CoV-2 infection. This review investigates the potential convergence of OD in PD and COVID-19, particularly focusing on the mechanisms by which neuroinflammation contributes to OD and neurological events. Starting from our fundamental understanding of the olfactory bulb, we summarize the clinical features of OD and pathological features of the olfactory bulb from clinical cases and autopsy reports in PD patients. We then examine SARS-CoV-2-induced olfactory bulb neuropathology and OD and emphasize the SARS-CoV-2-induced neuroinflammatory cascades potentially leading to PD manifestations. By activating microglia and astrocytes, as well as facilitating the aggregation of α-synuclein, SARS-CoV-2 could contribute to the onset or exacerbation of PD. We also discuss the possible contributions of NF-κB, the NLRP3 inflammasome, and the JAK/STAT, p38 MAPK, TLR4, IL-6/JAK2/STAT3 and cGAS-STING signaling pathways. Although olfactory dysfunction in patients with COVID-19 may be reversible, it is challenging to restore OD in patients with PD. With the emergence of new SARS-CoV-2 variants and the recurrence of infections, we call for continued attention to the intersection between PD and SARS-CoV-2 infection, especially from the perspective of OD.

Knockdown of NR4A1 alleviates doxorubicin-induced cardiotoxicity through inhibiting the activation of the NLRP3 inflammasome

Doxorubicin (DOX) is a widely used antitumor drug, but its clinical applicability is hampered by the unfortunate side effect of DOX-induced cardiotoxicity (DIC). In our current study, we retrieved three high-throughput sequencing datasets related to DIC from the Gene Expression Omnibus (GEO) datasets. We conducted differential analysis using R (DESeq2) to pinpoint differentially expressed genes (DEGs, and identified 11 genes that were consistently altered in both the control and DOX-treated groups. Notably, our Random Forest analysis of these three GEO datasets highlighted the significance of nuclear receptor subfamily 4 group A member 1 (NR4A1) in the context of DIC. The DOX-induced mouse model and cell model were used for the in vivo and in vitro studies to reveal the role of NR4A1 in DIC. We found that silencing NR4A1 by adeno-associated virus serotype 9 (AAV9) contained shRNA in vivo alleviated the DOX-induced cardiac dysfunction, cardiomyocyte injury and fibrosis. Mechanistically, we found NR4A1 silencing was able to inhibit DOX-induced the cleavage of NLRP3, IL-1β and GSDMD in vivo. Further in vitro studies have shown that inhibition of NR4A1 suppressed DOX-induced cytotoxicity and oxidative stress through the same molecular mechanism. We prove that NR4A1 plays a critical role in DOX-induced cardiotoxicity by inducing pyroptosis via activation of the NLRP3 inflammasome, and it might be a promising therapeutic target for DIC.

Role of pyroptosis in the pathogenesis of various neurological diseases

Pyroptosis, an inflammatory programmed cell death process, has recently garnered significant attention due to its pivotal role in various neurological diseases. This review delves into the intricate molecular signaling pathways governing pyroptosis, encompassing both caspase-1 dependent and caspase-1 independent routes, while emphasizing the critical role played by the inflammasome machinery in initiating cell death. Notably, we explore the Nucleotide-binding domain leucine-rich repeat (NLR) containing protein family, the Absent in melanoma 2-like receptor family, and the Pyrin receptor family as essential activators of pyroptosis. Additionally, we comprehensively examine the Gasdermin family, renowned for their role as executioner proteins in pyroptosis. Central to our review is the interplay between pyroptosis and various central nervous system (CNS) cell types, including astrocytes, microglia, neurons, and the blood-brain barrier (BBB). Pyroptosis emerges as a significant factor in the pathophysiology of each cell type, highlighting its far-reaching impact on neurological diseases. This review also thoroughly addresses the involvement of pyroptosis in specific neurological conditions, such as HIV infection, drug abuse-mediated pathologies, Alzheimer's disease, and Parkinson's disease. These discussions illuminate the intricate connections between pyroptosis, chronic inflammation, and cell death in the development of these disorders. We also conducted a comparative analysis, contrasting pyroptosis with other cell death mechanisms, thereby shedding light on their unique aspects. This approach helps clarify the distinct contributions of pyroptosis to neuroinflammatory processes. In conclusion, this review offers a comprehensive exploration of the role of pyroptosis in various neurological diseases, emphasizing its multifaceted molecular mechanisms within various CNS cell types. By elucidating the link between pyroptosis and chronic inflammation in the context of neurodegenerative disorders and infections, it provides valuable insights into potential therapeutic targets for mitigating these conditions.

Neutrophil extracellular trap-mediated impairment of meningeal lymphatic drainage exacerbates secondary hydrocephalus after intraventricular hemorrhage

Rationale: Hydrocephalus is a substantial complication after intracerebral hemorrhage (ICH) or intraventricular hemorrhage (IVH) that leads to impaired cerebrospinal fluid (CSF) circulation. Recently, brain meningeal lymphatic vessels (mLVs) were shown to serve as critical drainage pathways for CSF. Our previous studies indicated that the degradation of neutrophil extracellular traps (NETs) after ICH/IVH alleviates hydrocephalus. However, the mechanisms by which NET degradation exerts beneficial effects in hydrocephalus remain unclear. Methods: A mouse model of hydrocephalus following IVH was established by infusing autologous blood into both wildtype and Cx3cr1-/- mice. By studying the features and processes of the model, we investigated the contribution of mLVs and NETs to the development and progression of hydrocephalus following secondary IVH. Results: This study observed the widespread presence of neutrophils, fibrin and NETs in mLVs following IVH, and the degradation of NETs alleviated hydrocephalus and brain injury. Importantly, the degradation of NETs improved CSF drainage by enhancing the recovery of lymphatic endothelial cells (LECs). Furthermore, our study showed that NETs activated the membrane protein CX3CR1 on LECs after IVH. In contrast, the repair of mLVs was promoted and the effects of hydrocephalus were ameliorated after CX3CR1 knockdown and in Cx3cr1-/- mice. Conclusion: Our findings indicated that mLVs participate in the development of brain injury and secondary hydrocephalus after IVH and that NETs contribute to acute LEC injury and lymphatic thrombosis. CX3CR1 is a key molecule in NET-induced LEC damage and meningeal lymphatic thrombosis, which leads to mLV dysfunction and exacerbates hydrocephalus and brain injury. NETs may be a critical target for preventing the obstruction of meningeal lymphatic drainage after IVH.

Neuroinflammation Targeting Pyroptosis: Molecular Mechanisms and Therapeutic Perspectives in Stroke

Pyroptosis is a recently identified type of pro-inflammatory programmed cell death (PCD) mediated by inflammasomes and nucleotide oligomerization domain-like receptors (NLs) and dependent on members of the caspase family. Pyroptosis has been widely reported to participate in the occurrence and progression of various inflammatory diseases, including stroke, a frequently lethal disease with high prevalence and many complications. To date, there have been no effectively therapeutic strategies and methods for treating stroke. Pyroptosis is thought to be closely related to the occurrence and development of stroke. Understanding inflammatory responses induced by the activation of pyroptosis would be hopeful to provide feasible approaches and strategies. Targeting on molecules in the upstream or downstream of pyroptosis pathway has shown promise in the treatment of stroke. The present review summarizes current research on the characteristics of pyroptosis, the function and pathological phenomena of pyroptosis in stroke, the molecule mechanisms related to inflammatory pathways, and the drugs and other molecules that can affect outcomes after stroke. These findings may help identify possible targets or new strategies for the diagnosis and treatment of stroke.

Exosome lncRNA IFNG-AS1 derived from mesenchymal stem cells of human adipose ameliorates neurogenesis and ASD-like behavior in BTBR mice

BACKGROUND

The transplantation of exosomes derived from human adipose-derived mesenchymal stem cells (hADSCs) has emerged as a prospective cellular-free therapeutic intervention for the treatment of neurodevelopmental disorders (NDDs), as well as autism spectrum disorder (ASD). Nevertheless, the efficacy of hADSC exosome transplantation for ASD treatment remains to be verified, and the underlying mechanism of action remains unclear.

RESULTS

The exosomal long non-coding RNAs (lncRNAs) from hADSC and human umbilical cord mesenchymal stem cells (hUCMSC) were sequenced and 13,915 and 729 lncRNAs were obtained, respectively. The lncRNAs present in hADSC-Exos encompass those found in hUCMSC-Exos and are associated with neurogenesis. The biodistribution of hADSC-Exos in mouse brain ventricles and organoids was tracked, and the cellular uptake of hADSC-Exos was evaluated both in vivo and in vitro. hADSC-Exos promote neurogenesis in brain organoid and ameliorate social deficits in ASD mouse model BTBR T + tf/J (BTBR). Fluorescence in situ hybridization (FISH) confirmed lncRNA Ifngas1 significantly increased in the prefrontal cortex (PFC) of adult mice after hADSC-Exos intraventricular injection. The lncRNA Ifngas1 can act as a molecular sponge for miR-21a-3p to play a regulatory role and promote neurogenesis through the miR-21a-3p/PI3K/AKT axis.

CONCLUSION

We demonstrated hADSC-Exos have the ability to confer neuroprotection through functional restoration, attenuation of neuroinflammation, inhibition of neuronal apoptosis, and promotion of neurogenesis both in vitro and in vivo. The hADSC-Exos-derived lncRNA IFNG-AS1 acts as a molecular sponge and facilitates neurogenesis via the miR-21a-3p/PI3K/AKT signaling pathway, thereby exerting a regulatory effect. Our findings suggest a potential therapeutic avenue for individuals with ASD.

Rutin prevents pyroptosis and M1 microglia via Nrf2/Mac-1/caspase-1-mediated inflammasome axis to improve POCD

BACKGROUND

Neuroinflammation following peripheral surgery plays a key role in postoperative cognitive dysfunction (POCD) development and there is no effective therapy to inflammation-mediated cognitive impairment. Recent studies showed that rutin, a natural flavonoid compound, conferred neuroprotection. However, the effects and mechanisms of rutin on cognition of surgical and aged mice and LPS-induced BV2 need deeper exploration.

METHODS

The effect of rutin in vivo and vitro were evaluated by Morris water maze test, HE stainin, Golgi-Cox staining, IF, IHC, RT-PCR, Flow Cytometer and Western blotting. In vivo, aged mice were treated with rutin and surgery. In vitro, rutin, Nrf2 knockdown, MAC-1 overexpression and VX765, a caspase-1 inhibitor, were administration on BV2 microglial cells.

RESULTS

Surgery led to compensatory increase in nuclear Nrf2 and rutin could further increase it. Neural damage was accompanied with high level in MAC-1, caspase-1-mediated pyroptosis and M1 microglia, while rutin recovered the process. Nrf2 inhibition abolished the effect of rutin with the increase of MAC-1, caspase-1-mediated pyroptosis and M1 microglia. Activation of MAC-1 abrogated protection of rutin by increase in pyroptosis and M1 microglia. Finally, we found that treatment with VX765 improved injury and increased M2 microglia against overexpression of MAC-1.

CONCLUSIONS

Our study indicated that rutin may be a potential therapy in POCD and exerted neural protection via Nrf2/ Mac-1/ caspase-1-mediated inflammasome axis to regulate pyroptosis and microglial polarization.

Osteopontin modulates microglial activation states and attenuates inflammatory responses after subarachnoid hemorrhage in rats

AIMS

Osteopontin (OPN) has demonstrated neuroprotective effects in various stroke models. Its role in neuroinflammation after brain injury remains to be elucidated. This study aims to clarify the effect of OPN on neuroinflammation, particularly on the functional states of microglia after subarachnoid hemorrhage (SAH).

METHODS

77 rats were randomly divided into the following groups: Sham, SAH 24 h, SAH + rOPN, SAH + Vehicle (PBS), SAH + OPN siRNA, and SAH + Scr siRNA, SAH + rOPN+Fib-14 and SAH + rOPN+DMSO. Modified Garcia and beam balance tests were used to evaluate neurobehavioral outcomes. Semi-quantitative immunofluorescence staining was performed to measure expression of myeloperoxidase (MPO) and microglia activation state markers CD16, CD206 after SAH and recombinant OPN treatment. The quantification of microglia activation and functional markers CD16, CD206, TNF-α and IL-10 were further evaluated using Western-blotting.

RESULTS

Nasal administration of rOPN improved neurological dysfunction, attenuated neutrophil infiltration, and decreased expression of phenotypic and functional markers of pro-inflammatory microglia CD16 and TNF-α. It also promoted an anti-inflammatory microglial state, as evidenced by increased expression of CD206 and IL-10. Furthermore, after blocking the phosphorylation of FAK signaling, the effects of rOPN on microglial activation states were partially reversed. The downstream pathways of STAT3 and NF-κB also exhibited consistent changes, suggesting the involvement of the STAT3 and NF-κB pathways in OPN's modulation of microglial activation via integrin-FAK signaling.

CONCLUSION

OPN attenuates inflammatory responses after SAH by promoting an anti-inflammatory microglial state, potentially mediated through the integrin-FAK-STAT3 and NF-κB signaling pathways.

Mechanisms of PANoptosis and relevant small-molecule compounds for fighting diseases

Pyroptosis, apoptosis, and necroptosis are mainly programmed cell death (PCD) pathways for host defense and homeostasis. PANoptosis is a newly distinct inflammatory PCD pathway that is uniquely regulated by multifaceted PANoptosome complexes and highlights significant crosstalk and coordination among pyroptosis (P), apoptosis (A), and/or necroptosis(N). Although some studies have focused on the possible role of PANpoptosis in diseases, the pathogenesis of PANoptosis is complex and underestimated. Furthermore, the progress of PANoptosis and related agonists or inhibitors in disorders has not yet been thoroughly discussed. In this perspective, we provide perspectives on PANoptosome and PANoptosis in the context of diverse pathological conditions and human diseases. The treatment targeting on PANoptosis is also summarized. In conclusion, PANoptosis is involved in plenty of disorders including but not limited to microbial infections, cancers, acute lung injury/acute respiratory distress syndrome (ALI/ARDS), ischemia-reperfusion, and organic failure. PANoptosis seems to be a double-edged sword in diverse conditions, as PANoptosis induces a negative impact on treatment and prognosis in disorders like COVID-19 and ALI/ARDS, while PANoptosis provides host protection from HSV1 or Francisella novicida infection, and kills cancer cells and suppresses tumor growth in colorectal cancer, adrenocortical carcinoma, and other cancers. Compounds and endogenous molecules focused on PANoptosis are promising therapeutic strategies, which can act on PANoptosomes-associated members to regulate PANoptosis. More researches on PANoptosis are needed to better understand the pathology of human conditions and develop better treatment.

CXCR4-BTK axis mediate pyroptosis and lipid peroxidation in early brain injury after subarachnoid hemorrhage via NLRP3 inflammasome and NF-κB pathway

C-X-C chemokine receptor type 4 (CXCR4) is critical for homeostasis of the adaptive and innate immune system in some CNS diseases. Bruton's tyrosine kinase (BTK) is an essential kinase that regulates inflammation in immune cells through multiple signaling pathways. This study aims to explore the effect of CXCR4 and BTK on neuroinflammation in the pathogenesis of early brain injury (EBI) after subarachnoid hemorrhage (SAH). Our results showed that the expression of CXCR4 and p-BTK increased significantly at 24 h after SAH in vivo and in vitro. Ibrutinib improved neurological impairment, BBB disruption, cerebral edema, lipid peroxidation, neuroinflammation and neuronal death at 24 h after SAH. Inhibition of BTK phosphorylation promoted the in vitro transition of hemin-treated proinflammatory microglia to the anti-inflammatory state, inhibited the p-P65 expression and microglial pyroptosis. NLRP3 deficiency can significantly reduce pyroptosis in SAH mice. Moreover, CXCR4 inhibition can suppress NLRP3-mediated pyroptosis, NF-κB activation and NOX2 expression in vitro, and ibrutinib can abolish CXCR4-aggravated BBB damage and pyroptosis in EBI after SAH. The levels of CXCR4 in CSF of SAH patients is significantly increased, and it is positively correlated with GSDMD and IL-1β levels, and have a moderate diagnostic value for outcome at 6-month follow-up. Our findings revealed the effect of CXCR4 and P-BTK on NLRP3-mediated pyroptosis and lipid peroxidation after SAH in vivo and in vitro, and the potential diagnostic role of CXCR4 in CSF of SAH patients. Inhibition of CXCR4-BTK axis can significantly attenuate NLRP3-mediated pyroptosis and lipid peroxidation by regulating NF-κB activation in EBI after SAH.

CSF hypersecretion versus impaired CSF absorption in posthemorrhagic hydrocephalus: a systematic review

BACKGROUND

The molecular mechanisms underlying development of posthemorrhagic hydrocephalus (PHH) remain elusive. The aim of this systematic review was to evaluate existing literature on increased CSF secretion and impaired CSF absorption as pathogenic contributors to CSF accumulation in neonatal and adult PHH.

METHODS

The systematic review was conducted in accordance with the PRISMA guidelines. Relevant studies published before March 11th, 2023, were identified from PubMed and reference lists. Studies were screened for eligibility using predefined inclusion and exclusion criteria. Data from eligible studies were extracted and potential sources of bias were evaluated.

RESULTS

Nineteen studies quantified CSF production rates and/or CSF absorption capacity in human patients with PHH or animals with experimentally induced PHH. Increased CSF production was reported as early as 24 h and as late as 28 days post ictus in six out of eight studies quantifying CSF production rates in animals with experimentally induced PHH. Impaired CSF absorption was reported in all four studies quantifying CSF absorption capacity in human patients with PHH and in seven out of nine studies quantifying CSF absorption capacity in animals with experimentally induced PHH. Impaired CSF absorption was reported as early as 30 min and as late as 10 months post ictus.

CONCLUSIONS

The pathological CSF accumulation in PHH likely arises from a combination of increased CSF secretion and impaired CSF absorption, which may manifest at different time scales following a hemorrhagic event. Emergent evidence on increased CSF secretion by the choroid plexus may herald a paradigm shift in our understanding of PHH.

Natural compounds as lactate dehydrogenase inhibitors: potential therapeutics for lactate dehydrogenase inhibitors-related diseases

Lactate dehydrogenase (LDH) is a crucial enzyme involved in energy metabolism and present in various cells throughout the body. Its diverse physiological functions encompass glycolysis, and its abnormal activity is associated with numerous diseases. Targeting LDH has emerged as a vital approach in drug discovery, leading to the identification of LDH inhibitors among natural compounds, such as polyphenols, alkaloids, and terpenoids. These compounds demonstrate therapeutic potential against LDH-related diseases, including anti-cancer effects. However, challenges concerning limited bioavailability, poor solubility, and potential toxicity must be addressed. Combining natural compounds with LDH inhibitors has led to promising outcomes in preclinical studies. This review highlights the promise of natural compounds as LDH inhibitors for treating cancer, cardiovascular, and neurodegenerative diseases.

The Role of Neutrophil Extracellular Traps in Early Microthrombosis and Brain Injury After Subarachnoid Hemorrhage in Mice

Microthrombosis plays an important role in secondary brain injury after experimental subarachnoid hemorrhage (SAH), but the specific mechanism of microthrombosis remains unclear. The purpose of this study was to investigate the role of neutrophil extracellular traps (NETs) in microthrombosis after SAH. SAH was induced in male C57BL/6 mice using an endovascular perforation technique. The marker protein of NETs, citrullinated histone H3 (CitH3), was significantly elevated in the cerebral cortex after SAH, and was co-labeled with microthrombi. Both depletion of neutrophils by anti-Ly6G antibody and DNase I treatment significantly reduced the formation of NETs and microthrombi, and ameliorated neurological deficits, brain edema, BBB disruption, and neuronal injury at 24 h after SAH induction. Cerebral hypoperfusion in the first hours after SAH is a major determinant of poor neurological outcome; in this study, we found that DNase I treatment significantly improved the restoration of early cortical perfusion after SAH. In addition, DNase I treatment also significantly attenuated cerebrospinal fluid (CSF) flow after SAH, which was associated with the diffusion barrier caused by microthrombi in the paravascular space after SAH. In conclusion, NETs are associated with early microthrombosis after SAH; they may be a novel therapeutic target for early brain injury (EBI) after SAH.

Amentoflavone mitigates doxorubicin-induced cardiotoxicity by suppressing cardiomyocyte pyroptosis and inflammation through inhibition of the STING/NLRP3 signalling pathway

BACKGROUND

Doxorubicin (DOX) is a potent anticancer chemotherapeutic agent whose clinical application is substantially constrained by its cardiotoxicity. The pathophysiology of DOX-induced cardiotoxicity manifests as cardiomyocyte pyroptosis and inflammation. Amentoflavone (AMF) is a naturally occurring biflavone possessing anti-pyroptotic and anti-inflammatory properties. However, the mechanism through which AMF alleviates DOX-induced cardiotoxicity remains undetermined.

PURPOSE

This study aimed at investigating the role of AMF in alleviating DOX-induced cardiotoxicity.

STUDY DESIGN AND METHODS

To assess the in vivo effect of AMF, DOX was intraperitoneally administered into a mouse model to induce cardiotoxicity. To elucidate the underlying mechanisms, the activities of STING/NLRP3 were quantified using the NLRP3 agonist nigericin and the STING agonist amidobenzimidazole (ABZI). Primary cardiomyocytes isolated from neonatal Sprague-Dawley rats were treated with saline (vehicle) or DOX with or without AMF and/or ABZI. The echocardiogram, haemodynamics, cardiac injury markers, heart/body weight ratio, and pathological alterations were monitored; the STING/NLRP3 pathway-associated proteins were detected by western blot and cardiomyocyte pyroptosis was analysed by immunofluorescence staining of cleaved N-terminal GSDMD and scanning electron microscopy. Furthermore, we evaluated the potential of AMF in compromising the anticancer effects of DOX in human breast cancer cell lines.

RESULTS

AMF substantially alleviated cardiac dysfunction and reduced heart/body weight ratio and myocardial damage in mice models of DOX-induced cardiotoxicity. AMF effectively suppressed DOX-mediated upregulation of IL-1β, IL-18, TNF-α, and pyroptosis-related proteins, including NLRP3, cleaved caspase-1, and cleaved N-terminal GSDMD. The levels of apoptosis-related proteins, namely Bax, cleaved caspase-3, and BCL-2 were not affected. In addition, AMF inhibited STING phosphorylation in DOX-affected hearts. Intriguingly, the administration of nigericin or ABZI dampened the cardioprotective effects of AMF. The in vitro anti-pyroptotic effect of AMF was demonstrated in attenuating the DOX-induced reduction in cardiomyocyte cell viability, upregulation of cleaved N-terminal GSDMD, and pyroptotic morphology alteration at the microstructural level. AMF exhibited a synergistic effect with DOX to reduce the viability of human breast cancer cells.

CONCLUSION

AMF alleviates DOX-induced cardiotoxicity by suppressing cardiomyocyte pyroptosis and inflammation via inhibition of the STING/NLRP3 signalling pathway, thereby validating its efficacy as a cardioprotective agent.

Oestrogen ameliorates blood-brain barrier damage after experimental subarachnoid haemorrhage via the SHH pathway in male rats

BACKGROUND

Sex differences affect the occurrence, progression and regression of subarachnoid haemorrhage (SAH). Oestrogen plays a protective role in alleviating the vasospasm and neuronal apoptosis induced by SAH. However, whether oestrogen affects blood‒brain barrier (BBB) integrity has not been fully studied. Oestrogen has been found to regulate the sonic hedgehog (SHH) signalling pathway through the oestrogen receptor in gastric cancer and adrenal glands, and the SHH signalling pathway has an important role in maintaining the BBB by upregulating the expression of tight junction proteins. In this study, we investigated the relationship between oestrogen and the SHH signalling pathway using clinical data and established an experimental SAH model to explore whether oestrogen could ameliorate BBB damage after SAH through the SHH pathway.

METHODS

Correlations between oestrogen and the SHH pathway were analysed by patients' cerebrospinal fluid (CSF) samples and the Genotype-Tissue Expression database (GTEx). Then, an experimental rat SAH model was established using the endovascular perforation method and treated with oestrogen, oestrogen inhibitors and SHH signalling pathway inhibitors. Then, the effects of oestrogen on BBB damage were analysed by western blot, immunofluorescence and neurobehavioural experiments.

RESULTS

ESLIA detection and correlation analysis showed that oestrogen levels in patients' CSF were positively correlated with the SHH pathway, which was further verified by GTEx gene-correlation analysis. SHH was found to be mainly expressed in neurons and astrocytes in rats under physiological conditions and was upregulated by oestrogen pretreatment. In the SAH model, oestrogen pretreatment was found to reverse SAH-induced decreases in the SHH pathway, which were counteracted by oestrogen receptor inhibitors. Furthermore, oestrogen pretreatment reduced SAH-induced BBB damage, brain oedema and neurological dysfunction, which were eliminated by SHH pathway inhibitors.

CONCLUSION

In conclusion, we demonstrate here that oestrogen pretreatment ameliorates brain injury after SAH, at least in part through SHH pathway-mediated BBB protection.

Circadian Rhythm Regulator REV-ERBα Attenuates Neuroapoptosis in Early Brain Injury After Experimental Subarachnoid Hemorrhage in Rats

Subarachnoid hemorrhage (SAH) is associated with circadian rhythm abnormalities, in which REV-ERBα plays a major regulatory role. Our ambition was to investigate the capacity of REV-ERBα to inhibit neuronal neuroapoptosis induced by early brain injury (EBI) after SAH. The endovascular perforation model was used to produce experimental SAH in Sprague-Dawley rats. Specific small-interfering RNA was used to downregulate the expression REV-ERBα while SR9009 was used to upregulate the expression before assessments. Short- and long-term neurobehavior assessments, immunofluorescence staining, TUNEL staining, Nissl staining, brain water content, and Western blot were performed. The expression level of endogenous REVERBα tended to increase and then decrease after SAH and peaked at 48 h. REV-ERBα upregulation diminished neuronal apoptosis and enhanced neurological function deficits. Meanwhile, REV-ERBα downregulation aggravated the damage. Furthermore, the levels of downstream proteins of REV-ERBα (i.e., brain and muscle ARNT-like 1 (BMAL1) and circadian locomotor output cycles kaput (CLOCK)) changed accordingly with REV-ERBα regulation. REV-ERBα may attenuate neuronal apoptosis in EBI after SAH through the BMAL1/CLOCK pathway.

The role of the astrocyte in subarachnoid hemorrhage and its therapeutic implications

Subarachnoid hemorrhage (SAH) is an important public health concern with high morbidity and mortality worldwide. SAH induces cell death, blood−brain barrier (BBB) damage, brain edema and oxidative stress. As the most abundant cell type in the central nervous system, astrocytes play an essential role in brain damage and recovery following SAH. This review describes astrocyte activation and polarization after SAH. Astrocytes mediate BBB disruption, glymphatic–lymphatic system dysfunction, oxidative stress, and cell death after SAH. Furthermore, astrocytes engage in abundant crosstalk with other brain cells, such as endothelial cells, neurons, pericytes, microglia and monocytes, after SAH. In addition, astrocytes also exert protective functions in SAH. Finally, we summarize evidence regarding therapeutic approaches aimed at modulating astrocyte function following SAH, which could provide some new leads for future translational therapy to alleviate damage after SAH.

BTB domain and CNC homolog 1 promotes glioma invasion mainly through regulating extracellular matrix and increases ferroptosis sensitivity

BTB Domain and CNC Homolog 1 (Bach1) has been implicated in cancer progression, particularly in invasion, but little is unknown about its effect on glioma. Here, we confirmed that highly expressed Bach1 prominently promoted glioma invasion. Similar to the reported mechanisms in other tumors, Bach1 upregulation was also correlated with epithelial mesenchymal transition (EMT) in glioma cells. More importantly, proteomic analysis indicated that the main mechanism of Bach1 promoting invasion in glioma involved extracellular matrix (ECM). We further found thatBach1 upregulation was associated with the multiple mechanisms of ECM remodeling in glioma, including increasing the expression and deposition of ECM components, activating TGFBR2-smad2/3 signaling, promoting invadopodia formation and inducing the expression and secretion of MMP2. Meanwhile, Bach1 overexpression increased ferroptosis sensitivity in glioma cells. The ferroptosis inducer (sulfasalazine) obviously suppressed the gliomas with Bach1 upregulation in vitro and in vivo. Overall, Bach1 has a two-faced role in glioma. Highly expressed Bach1 promotes glioma invasion. Conversely, Bach1 upregulation is also a potential indicator of the sensitivity of ferroptosis inducers.

Rethinking the initial changes in subarachnoid haemorrhage: Focusing on real-time metabolism during early brain injury

Over the last two decades, neurological researchers have uncovered many pathophysiological mechanisms associated with subarachnoid haemorrhage (SAH), with early brain injury and delayed cerebral ischaemia both contributing to morbidity and mortality. The current dilemma in SAH management inspired us to rethink the nature of the insult in SAH: sudden bleeding into the subarachnoid space and hypoxia due to disturbed cerebral circulation and increased intracranial pressure, generating exogenous stimuli and subsequent pathophysiological processes. Exogenous stimuli are defined as factors which the brain tissue is not normally exposed to when in the healthy state. Intersections of these initial pathogenic factors lead to secondary brain injury with related metabolic changes after SAH. Herein, we summarized the current understanding of efforts to monitor and analyse SAH-related metabolic changes to identify those precise pathophysiological processes and potential therapeutic strategies; in particular, we highlight the restoration of normal cerebrospinal fluid circulation and the normalization of brain-blood interface physiology to alleviate early brain injury and delayed neurological deterioration after SAH.

NLRP3 Inflammasome Overactivation in Patients with Aneurysmal Subarachnoid Hemorrhage

Aneurysmal subarachnoid hemorrhage (aSAH) is an uncommon and severe subtype of stroke leading to the loss of many years of productive life. We analyzed NLRP3 activity as well as key components of the inflammasome cascade in monocytes and plasma from 28 patients with aSAH and 14 normal controls using flow cytometry, western blot, ELISA, and qPCR technologies. Our data reveal that monocytes from patients with aSAH present an overactivation of the NLRP3 inflammasome, which results in the presence of high plasma levels of interleukin (IL)-1β, IL-18, gasdermin D, and tissue factor. Although further research is needed, we propose that serum tissue factor concentration might be a useful prognosis biomarker for clinical outcome, and for Tako-Tsubo cardiomyopathy and cerebral vasospasm prediction. Remarkably, MCC-950 inhibitor effectively blocks NLRP3 activation in aSAH monocyte culture and supresses tissue factor release to the extracellular space. Finally, our findings suggest that NLRP3 activation could be due to the release of erythrocyte breakdown products to the subarachnoid space during aSAH event. These data define NLRP3 activation in monocytes from aSAH patients, indicating systemic inflammation that results in serum TF upregulation which in turns correlates with aSAH severity and might serve as a prognosis biomarker for aSAH clinical outcome and for cerebral vasospasm and Tako-Tsubo cardiomyopathy prediction.

Biological Effects and Mechanisms of Caspases in Early Brain Injury after Subarachnoid Hemorrhage

Caspases are an evolutionarily conserved family of proteases responsible for mediating and initiating cell death signals. In the past, the dysregulated activation of caspases was reported to play diverse but equally essential roles in neurodegenerative diseases, such as brain injury and neuroinflammatory diseases. A subarachnoid hemorrhage (SAH) is a traumatic event that is either immediately lethal or induces a high risk of stroke and neurological deficits. Currently, the prognosis of SAH after treatment is not ideal. Early brain injury (EBI) is considered one of the main factors contributing to the poor prognosis of SAH. The mechanisms of EBI are complex and associated with oxidative stress, neuroinflammation, blood-brain barrier disruption, and cell death. Based on mounting evidence, caspases are involved in neuronal apoptosis or death, endothelial cell apoptosis, and increased inflammatory cytokine-induced by apoptosis, pyroptosis, and necroptosis in the initial stages after SAH. Caspases can simultaneously mediate multiple death modes and regulate each other. Caspase inhibitors (including XIAP, VX-765, and Z-VAD-FMK) play an essential role in ameliorating EBI after SAH. In this review, we explore the related pathways mediated by caspases and their reciprocal regulation patterns after SAH. Furthermore, we focus on the extensive crosstalk of caspases as a potential area of research on therapeutic strategies for treating EBI after SAH.