Low-dose LPS alleviates early brain injury after SAH by modulating microglial M1/M2 polarization via USP19/FOXO1/IL-10/IL-10R1 signaling

Dynamic development of microglia and macrophages after spinal cord injury

JOURNAL/nrgr/04.03/01300535-202512000-00029/figure1/v/2025-01-31T122243Z/r/image-tiff Secondary injury following spinal cord injury is primarily characterized by a complex inflammatory response, with resident microglia and infiltrating macrophages playing pivotal roles. While previous studies have grouped these two cell types together based on similarities in structure and function, an increasing number of studies have demonstrated that microglia and macrophages exhibit differences in structure and function and have different effects on disease processes. In this study, we used single-cell RNA sequencing and spatial transcriptomics to identify the distinct evolutionary paths of microglia and macrophages following spinal cord injury. Our results showed that microglia were activated to a pro-inflammatory phenotype immediately after spinal cord injury, gradually transforming to an anti-inflammatory steady state phenotype as the disease progressed. Regarding macrophages, our findings highlighted abundant communication with other cells, including fibroblasts and neurons. Both pro-inflammatory and neuroprotective effects of macrophages were also identified; the pro-inflammatory effect may be related to integrin β2 ( Itgb2 ) and the neuroprotective effect may be related to the oncostatin M pathway. These findings were validated by in vivo experiments. This research underscores differences in the cellular dynamics of microglia and macrophages following spinal cord injury, and may offer new perspectives on inflammatory mechanisms and potential therapeutic targets.

Exploring medical gas therapy in hemorrhagic stroke treatment: A narrative review

Hemorrhagic stroke (HS) is a neurological disorder caused by the rupture of cerebral blood vessels, resulting in blood seeping into the brain parenchyma and causing varying degrees of neurological impairment, including intracerebral hemorrhage (ICH) and subarachnoid hemorrhage (SAH). Current treatment methods mainly include hematoma evacuation surgery and conservative treatment. However, these methods have limited efficacy in enhancing neurological function and prognosis. The current challenge in treating HS lies in inhibiting the occurrence and progression of secondary brain damage after bleeding, which is a key factor affecting the prognosis of HS patients. Studies have shown that medical gas therapy is gaining more attention and has demonstrated various levels of neuroprotective effects on central nervous system disorders, such as hyperbaric oxygen, hydrogen sulfide, nitric oxide, carbon monoxide, and other inhalable gas molecules. These medical gas molecules primarily improve brain tissue damage and neurological dysfunction by regulating inflammation, oxidative stress, apoptosis, and other processes. However, many of these medical gasses also possess neurotoxic properties. Therefore, the use of medical gases in HS deserves further exploration and research. In this review, we will elucidate the therapeutic effects and study the advances in medical gas molecules in HS.

Ginsenoside Rg3 alleviates brain damage caused by chlorpyrifos exposure by targeting and regulating the microbial-gut-brain axis

INTRODUCTION

The utilization of organophosphorus pesticides (OPs) has been demonstrated to exert a substantial positive influence on crop yield enhancement. However, due to the multitude of exposure routes and the persistence of these compounds, humans are routinely exposed to pesticides on a daily basis through dermal contact, inhalation, and ingestion. This has serious consequences for the health of living organisms. The existing research on the effects of organophosphorus pesticides on organisms primarily encompasses the impact on vital organs such as the liver, kidneys, heart, various blood parameters, and potential neurotoxicity, teratogenicity, carcinogenicity, and mutagenic effects. However, there is a paucity of research addressing the alleviation of brain tissue damage in OP pesticide poisoning through the microbial-intestinal-brain axis.

OBJECTIVES

The objective of the present study is to illuminate the biological activity and mechanism of ginsenoside Rg3 in addressing brain injury induced by chlorpyrifos, employing both in vivo and in vitro models. This investigation will elucidate the role of the microbiota-gut-brain axis and the polarization of macrophages in this process.

METHODS AND RESULTS

Ginsenoside Rg3 is characterized by notable antioxidant and neuroprotective properties. The results showed that Rg3 improved the cognitive and learning memory impairment after chlorpyrifos (CPF) exposure in C57 mice, alleviated macrophage infiltration in the hippocampus, repaired synaptic ultrastructural damage and restored the absence of synapse-related proteins (BDNF, SYP, and PSD-95) through behavioral assays, ameliorated neuronal apoptosis and hypothalamo-pituitary-adrenal axis (HPA axis) disorders, and mediated the development of MPA axis disorders, while mediating M1/M2 macrophage polarization and attenuating apoptosis in brain tissue. In intestinal tissues, Rg3 improved the intestinal flora of mice, significantly reduced macrophage infiltration, and down-regulated the expression of pro-inflammatory cytokines (tumor necrosis factor-α, IL-1β, and IL-6), while concurrently augmenting the levels of short-chain fatty acids. And the therapeutic role of Rg3 in ameliorating the brain damage induced by chlorpyrifos exposure was substantiated by protein imprinting through the NLRP3/Caspase-1/IL-1β signaling pathway. Meanwhile, the results of in vitro experiments demonstrated that ginsenoside Rg3 could attenuate CPF-induced inflammatory responses in BV-2 microglia by modulating M1/M2 macrophage polarization.

CONCLUSION

The results of this study confirmed that ginsenoside Rg3 can be utilized as a promising therapeutic strategy to mitigate brain tissue damage resulting from OP-type pesticide poisoning. These findings suggest that Rg3 has the potential to serve as a promising clinical drug for the treatment of organs affected by organophosphorus pesticide poisoning. This study offers novel insights into the application of Rg3 in the context of the microbial-gut-brain axis, providing a theoretical foundation for the development of ginsenoside Rg3 in clinical settings and the future development of novel drugs.

Pioglitazone Modulates Microglia M1/M2 Polarization Through PPAR-γ Pathway and Exerts Neuroprotective Effects in Experimental Subarachnoid Hemorrhage

Subarachnoid hemorrhage (SAH), a subtype of hemorrhagic stroke primarily resulting from the rupture of intracranial aneurysms, remains a significant contributor to disability and mortality, notwithstanding advancements in treatment. This study investigates the neuroprotective effects of pioglitazone in SAH, focusing on the PPAR-γ pathway and its potential role in mitigating early brain injury (EBI) following SAH. Neuroprotective efficacy was assessed through neurobehavioral assessment, brain water content analysis, TUNEL, immunofluorescence, western blotting, and inflammatory factor assay. Results indicate that pioglitazone treatment effectively mitigated brain edema, reduced neuronal death, and enhanced short-term neurobehavioral function in SAH-afflicted rats. Furthermore, pioglitazone demonstrated sustained improvements in long-term neurobehavioral function and decreased neuronal loss post-SAH. Mechanistically, SAH induced the polarization of microglia towards the M1 phenotype and the release of pro-inflammatory cytokines. Conversely, pioglitazone treatment predominantly shifted microglia polarization towards the M2 phenotype, eliciting a notable release of anti-inflammatory cytokines. Notably, the positive effects of pioglitazone were nullified by the PPAR-γ inhibitor T0070907. In conclusion, our findings suggest that pioglitazone may alleviate neuroinflammation by modulating microglia M1/M2 polarization through the PPAR-γ pathway, thereby conferring neuroprotection against SAH injury and positing itself as a potential therapeutic agent for SAH treatment.

Activation of central Angiotensin-(1-7)/Mas receptor alleviates synaptic damage in diabetes-associated cognitive impairment via modulating AKT/FOXO1/PACAP axis

Synaptic damage is a pathological hallmark of diabetes-associated cognitive impairment (DACI). Angiotensin-(1-7)/Mas receptor has been implicated in regulating peripheral glucose homeostasis and exerting neuroprotective effects on central nervous system. This study investigated the possible roles of Angiotensin-(1-7)/Mas receptor in DACI, aiming to elucidate the molecular mechanisms underlying synaptic damage. We observed a significant reduction of Angiotensin-(1-7) levels in type 2 diabetic patients with mild cognitive impairment and diabetic cognitive impairment mice. Downregulation of Angiotensin-(1-7)/Mas receptor was associated with the decreased synaptic protein expressions in diabetic cognitive impairment mice, and high glucose-stimulated primary hippocampal neurons. Administration of the Mas agonist AVE 0991 into the hippocampus effectively ameliorated synaptic and memory dysfunctions in diabetic cognitive impairment mice. Inhibition of hippocampal neuronal Mas receptor aggravated synaptic damage. Mechanistically, we first elucidated that pituitary adenylate cyclase-activating polypeptide (PACAP) serves as a downstream synaptic function-related target gene of Mas receptor. Furthermore, we identified AKT/FOXO1 pathway as a critical downstream mediator of Mas receptor in modulating PACAP expression, with FOXO1 binding directly to the PACAP promoter region. In conclusion, Angiotensin-(1-7)/Mas receptor may modulate synaptic function-related target gene PACAP expression through AKT/FOXO1 pathway, thereby providing a deeper theoretical basis and molecular target for future DACI treatment.

Tenascin-C Facilitates Microglial Polarization via TLR4/MyD88/NF-κB Pathway Following Subarachnoid Hemorrhage

Purpose

This study primarily aims to elucidate the underlying mechanism of Tenascin-C in neuroinflammation and microglia polarization in a mouse model of subarachnoid hemorrhage (SAH).

Methods

The subarachnoid hemorrhage model was constructed by injecting blood into the anterior chiasmatic cistern and stimulating primary microglia with hemoglobin in vitro. Then, Imatinib mesylate was used to inhibit Tenascin-C. Through neurological function scoring, brain edema, primary cell extraction, immunofluorescence staining, CCK8, Tunel staining, Elisa, Western blot and other methods, the potential mechanism of Tenascin-C induced microglia cell polarization was explored.

Results

The results of this study observed that the expression of Tenascin-C was up-regulated after subarachnoid hemorrhage. Inhibiting the increase of Tenascin-C by imatinib could significantly ameliorate neuroinflammation, neuronal apoptosis, blood brain barrier disruption and brain edema. When the level of Tenascin-C decreased, the numbers of TLR4 positive, MyD88 positive and NF-κB positive microglial cells decreased accordingly. Moreover, after subarachnoid hemorrhage, the number of microglial cells positive for M1-type markers increased significantly. After imatinib inhibited Tenascin-C, the number of M1-type microglial cells decreased and the number of M2-type microglial cells increased significantly.

Conclusion

In summary, the elevated level of Tenascin-C after subarachnoid hemorrhage induces the activation of microglia, releasing a large number of inflammatory factors and aggravating early brain injury.

MicroRNAs Associated with Parenchymal Hematoma After Endovascular Mechanical Reperfusion for Acute Ischemic Stroke in Rats

Background/Objectives: Hemorrhagic transformation after endovascular thrombectomy predicts poor outcomes in acute ischemic stroke with large-vessel occlusion. The roles of microRNAs (miRNAs) in the pathogenesis of parenchymal hematoma (PH) after endovascular thrombectomy still remain unclear. This study aimed to investigate the miRNA and mRNA regulatory network associated with PH after mechanical reperfusion in an animal stroke model and an oxygen-glucose deprivation/reoxygenation (OGD/R) model. Methods: Twenty-five miRNAs were assessed in a mechanical reperfusion-induced hemorrhage transformation model in rats under hyperglycemic conditions receiving 5 h middle cerebral artery occlusion. The differentially expressed miRNAs associated with PH were assessed in a neuron, astrocyte, microglia, brain microvascular endothelial cell (BMEC), and pericyte model of OGD/R. The predicted target genes of the differentially expressed miRNAs were further assessed in the animal model. The miRNA-mRNA regulatory network of PH was established. Results: Thirteen down-regulated miRNAs (miRNA-29a-5p, miRNA-29c-3p, miRNA-126a-5p, miRNA-132-3p, miRNA-136-3p, miRNA-142-3p, miRNA-153-5p, miRNA-218a-5p, miRNA-219a-2-3p, miRNA-369-5p, miRNA-376a-5p, miRNA-376b-5p, and miRNA-383-5p) and one up-regulated miRNA (miRNA-195-3p) were found in the rat peri-infarct with PH after mechanical reperfusion. Of these 14 PH-related miRNAs, 10 were significantly differentially expressed in at least two of the five neuron, astrocyte, microglia, BMEC, and pericyte models after OGD/R, consistent with the animal stroke model results. Thirty-one predicted hub target genes were significantly differentially expressed in the rat peri-infarct with PH after mechanical reperfusion. Forty-nine miRNA-mRNA regulatory axes of PH were revealed, and they were related to the mechanisms of inflammation, immunity, oxidative stress, and apoptosis. Conclusions: Fourteen miRNAs were associated with PH after mechanical reperfusion in the rat stroke and the OGD/R models. Simultaneously differentially expressed miRNAs and related genes in several cells of the neurovascular unit may serve as valuable targets for PH after endovascular thrombectomy in acute ischemic stroke.

Suppression of Hepatocyte Ferroptosis via USP19-Mediated Deubiquitination of SLC7A11 in Ischemia-Free Liver Transplantation

Ischemia-free liver transplantation (IFLT) is developed as a novel clinical approach to avoid ischemia-reperfusion injury (IRI). This study aims to identify the most distinguished programmed cell death pathway in grafts undergoing IFLT versus conventional liver transplantation (CLT) and to explore the underlying mechanism. Ferroptosis is the most distinct programmed cell death form between IFLT and CLT grafts. Among various cell death inhibitors, the ferroptosis inhibitor (Ferrostain-1) is the most effective one to prevent hepatocytes from damage induced by oxygen deprivation/reoxygenation (OGD/R). Hepatocyte ferroptosis is significantly alleviated in IFLT versus CLT grafts in both human beings and pigs. Ubiquitination enzyme screening identifies augmented amounts of ubiquitin-specific protease 19 (USP19) in IFLT versus CLT grafts. The upregulation of USP19 in the grafts is correlated with reduced pathological Suzuki's score, lower post-transplant peak liver enzyme level, and less early allograft dysfunction in liver transplant recipients. USP19 overexpression mitigates post-transplant liver injury in mice. Mechanistically, USP19 inhibits the degradation of solute carrier family 7 member 11 (SLC7A11) by removing its K63-linked ubiquitin chains. Notably, USP19 overexpression reduces ferroptosis and IRI in a SLC7A11-dependent manner in mice. Collectively, USP19-mediated suppression of hepatocyte ferroptosis via deubiquitinating SLC7A11 is a key mechanism by which IFLT abrogates graft IRI.

Research progress of early brain Injury in subarachnoid hemorrhage from 2004 to 2024: a bibliometric analysis

Early brain injury (EBI) after subarachnoid hemorrhage (SAH) is a clear correlation with poor prognosis. In the past 20 years, the research on EBI has increased rapidly. However, there is a lack of bibliometric analysis related to EBI. The purpose of this study was to identify emerging targets for the treatment of EBI and analyze the current situation and trend of EBI post-SAH in the past 20 years through bibliometric analysis. EBI related literature was retrieved from Web of Science Core Collection during 2004-2024, and analyzed by Microsoft Office Excel 2023, CiteSpace, and VOSviewer. 1364 articles were retrieved, and finally 1271 articles were involved in the analysis. The number of EBI-related articles has grown steadily over the past 20 years. China cooperated most closely with other countries. Loma Linda University was the most productive institution and John H Zhang was the most prolific author. The most productive and co-cited journals were Translational Stroke Research and Stroke, respectively. The burst keywords suggested that EBI research was focusing on cell inflammation and multiple mechanisms of cell damage. This is the first bibliometric analysis of EBI-related studies after SAH. As a critical period for the treatment of SAH, our study will provide a good direction for future investigators.

The sentinel against brain injury post-subarachnoid hemorrhage: efferocytosis of erythrocytes by leptomeningeal lymphatic endothelial cells

Rationale: The clearance of extravasated erythrocytes represents the most reasonable strategy against brain injury post-subarachnoid hemorrhage (SAH). There is little knowledge about the autologous clearance of extravasated erythrocytes post-SAH. The leptomeningeal lymphatic endothelial cells (LLECs) have been less studied functionally, which were firstly harvested and cultured in vitro by our group previously and are probably related to the clearance of extravasated erythrocytes post-SAH for they closely surround subarachnoid space. Methods: We established a SAH animal model, employed primary LLECs in vitro, mimicked the conditions of the SAH in vitro, performed RNA sequencing, and transfected LLECs with adenovirus and adeno-associated virus both in vivo and in vitro to reveal the molecular mechanisms of efferocytosis of erythrocytes by LLECs and its neuroprotection post-SAH. Results: Firstly, we demonstrated the eryptosis-initiated degradation of extravasated erythrocytes in vitro. Furthermore, we found LLECs preferentially adhered and engulfed apoptotic erythrocytes in vivo and in vitro while sparing from intact erythrocytes, suggesting their novel capacity in the efferocytosis of erythrocytes. Additionally, the efferocytosis of erythrocytes by LLECs plays a role on neuroprotection via improving neurological functions, maintaining neurostructural integrity, and alleviating neuropathological consequences post-SAH. During efferocytosis, phosphatidylserine (PS) and phosphatidylserine receptor (PSR) mediated the recognition of apoptotic erythrocytes by LLECs. We also confirmed that NHL repeat-containing 2 (NHLRC2) positively regulated the efferocytosis of erythrocytes by LLECs to serve as a central regulator in it mediated neuroprotection post-SAH. Conclusions: This study elucidated the efferocytosis of erythrocytes by LLECs and subsequently neuroprotection post-SAH. These findings highlight a prompt, efficient, and regulable pathway for the autologous clearance of extravasated erythrocytes that performs as a sentinel against brain injury post-SAH.

An Ultrasound-Activated Supramolecular Modulator Enhancing Autophagy to Prevent Ventricular Arrhythmias Post-Myocardial Infarction

Ventricular arrhythmias (VAs) triggered by myocardial infarction (MI) are the leading cause of sudden cardiac mortality worldwide. Current therapeutic strategies for managing MI-induced VAs, such as left stellate ganglion resection and ablation, are suboptimal, highlighting the need to explore safer and more effective intervention strategies. Herein, we rationally designed two supramolecular sonosensitizers RuA and RuB, engineered through acceptor modification to generate moderate reactive oxygen species (ROS) to modulate VAs. Both RuA and RuB demonstrated high ultrasound (US)-activated ROS production efficiency, with singlet oxygen (1O2) quantum yield (ΦΔ) of 0.70 and 0.88, respectively, surpassing ligand IR1105 and the conventional sonosensitizer ICG (ΦΔ=0.40). In vitro, RuB, at a modest concentration and under US intensity notably boosts pro-survival autophagy in microglia BV2 cell. To improve in vivo stability and biocompatibility, RuB was further encapsulated into DSPE-PEG5000 to prepare RuB nanoparticles (RuB NPs). In vivo studies after microinjection of RuB NPs into the paraventricular nucleus (PVN) and subsequent US exposure, demonstrated that RuB NPs-mediated US modulation effectively suppresses sympathetic nervous activity (SNA) and inflammatory responses, thereby preventing VAs. Importantly, no tissue injury was observed post RuB NPs-mediated US modulation. This work pioneers the design of long-wave emission supramolecular sonosensitizers, offering new insights into regulating cardiovascular diseases.

Identification of core genes related to exosomes and screening of potential targets in periodontitis using transcriptome profiling at the single-cell level

BACKGROUND

The progression and severity of periodontitis (PD) are associated with the release of extracellular vesicles by periodontal tissue cells. However, the precise mechanisms through which exosome-related genes (ERGs) influence PD remain unclear. This study aimed to investigate the role and potential mechanisms of key exosome-related genes in PD using transcriptome profiling at the single-cell level.

METHODS

The current study cited GSE16134, GSE10334, GSE171213 datasets and 19,643 ERGs. Initially, differential expression analysis, three machine learning (ML) models, gene expression analysis and receiver operating characteristic (ROC) analysis were proceeded to identify core genes. Subsequently, a core gene-based artificial neural network (ANN) model was built to evaluate the predictive power of core genes for PD. Gene set enrichment analysis (GSEA) and immunoinfiltration analysis were conducted based on core genes. To pinpoint key cell types influencing the progression of periodontal at the single-cell level, a series of single-cell analyses covering pseudo-time series analysis were accomplished. The expression verification of core genes was performed through quantitative reverse transcription polymerase chain reaction (qRT-PCR).

RESULTS

CKAP2, IGLL5, MZB1, CXCL6, and AADACL2 served as core genes diagnosing PD. Four core gene were elevated in the PD group in addition to down-regulated AADACL2. The core gene-based-ANN model had AUC values of 0.909 in GSE16134 dataset, which exceeded AUC of each core gene, highlighting the accurately and credibly predictive performance of ANN model. GSEA revealed that ribosome was co-enriched by 5 core genes, manifesting the expression of these genes might be critical for protein structure or function. Immunoinfiltration analysis found that CKAP2, IGLL5, MZB1, and CXCL6 exhibited positive correlations with most discrepant immune cells/discrepant stromal cells, which were highly infiltrated in PD. B cells and T cells holding crucial parts in PD were identified as key cell types. Pseudo-time series analysis revealed that the expression of IGLL5 and MZB1 increased during T cell differentiation, increased and then decreased during B cell differentiation. The qRT-PCR proved the mRNA expression levels of CKAP2 and MZB1 were increased in the blood of PD patients compared to controls. But the mRNA expression levels of AADACL2 was decreased in the PD patients compared to controls. This is consistent with the trend in the amount of expression in the dataset.

CONCLUSION

CKAP2, IGLL5, MZB1, CXCL6 and AADACL2 were identified as core genes associated with exosomes, helping us to understand the role of these genes in PD.

Insulin Resistance Predicts Prognosis in Patients With Subarachnoid Hemorrhage

OBJECTIVE

The objective of this study was to determine whether insulin resistance (IR) could be used as a predictor of poor prognosis at 3 months after subarachnoid hemorrhage (SAH).

METHODS

The study included patients aged 18 years or older with a confirmed diagnosis of SAH due to ruptured aneurysm from January 2021 to March 2024. Patients with confirmed diabetes mellitus and taking glucose-lowering drugs, or taking lipid-lowering drugs, or SAH not due to ruptured aneurysm, or comorbid systemic diseases were excluded. Patients were classified into good prognosis (modified Rankin scale [MRS] 0-2) and poor prognosis (MRS 3-6). Receiver operating characteristic curve (ROC), least absolute shrinkage and selection operator (LASSO) analysis, and multivariate logistic regression analysis were used to determine the potential of triglyceride-glucose (TyG) index and the triglyceride to high-density lipoprotein cholesterol (TG/HDL) ratio as predictors of poor prognosis. Finally, a prognostic prediction model based on IR was constructed.

RESULTS

A total of 358 patients were included in this study. Poor prognosis patients had higher age, BMI, hypertension percentage, glucose, triglycerides, TyG index and TG/HDL ratio, and lower HDL. ROC, LASSO, and multivariate logistic regression analysis revealed that age, glucose, TyG index, and TG/HDL ratio had significant potential to predict the prognosis of SAH patients. The prognostic prediction model constructed by combining age, glucose, TyG index, and TG/HDL ratio had high discriminatory power (area under the curve [AUC] = 0.80), satisfactory calibration curves, and good clinical utility.

CONCLUSION

IR is strongly associated with the prognosis of SAH patients, and the combination of age, glucose, TyG index, and TG/HDL ratio can provide a new direction for future treatment.

Exosomes-mediated delivery of miR-486-3p alleviates neuroinflammation via SIRT2-mediated inhibition of mitophagy after subarachnoid hemorrhage

BACKGROUND

Neuroinflammation participates in the pathogenesis of subarachnoid haemorrhage (SAH); however, no effective treatments exist. MicroRNAs regulate several aspects of neuronal dysfunction. In a previous study, we found that exosomal miR-486-3p is involved in the pathophysiology of SAH. Targeted delivery of miR-486-3p without blood-brain barrier (BBB) restriction to alleviate SAH is a promising neuroinflammation approach.

METHODS

In this study, we modified exosomes (Exo) to form an RVG-miR-486-3p-Exo (Exo/miR) to achieve targeted delivery of miR-486-3p to the brain. Neurological scores, brain water content, BBB damage, flow cytometry and FJC staining were used to determine the effect of miR-486-3p on SAH. Western blot analysis, ELISA and RT-qPCR were used to measure relevant protein and mRNA levels. Immunofluorescence staining and laser confocal detection were used to measure the expression of mitochondria, lysosomes and autophagosomes, and transmission electron microscopy was used to observe the level of mitophagy in the brain tissue of mice after SAH.

RESULTS

Tail vein injection of Exo/miR improved targeting of miR-486-3p to the brains of SAH mice. The injection reduced levels of neuroinflammation-related factors by changing the phenotype switching of microglia, inhibiting the expression of sirtuin 2 (SIRT2) and enhancing mitophagy. miR-486-3p treatment alleviated neurobehavioral disorders, brain oedema, BBB damage and neurodegeneration. Further research found that the mechanism was achieved by regulating the acetylation level of peroxisome proliferator-activated receptor γ coactivator l alpha (PGC-1α) after SIRT2 enters the nucleus.

CONCLUSION

Exo/miR treatment attenuates neuroinflammation after SAH by inhibiting SIRT2 expression and stimulating mitophagy, suggesting potential clinical applications.

The potential therapeutic role of itaconate and mesaconate on the detrimental effects of LPS-induced neuroinflammation in the brain

Despite advances in antimicrobial and anti-inflammatory treatment, inflammation and its consequences remain a major challenge in the field of medicine. Inflammatory reactions can lead to life-threatening conditions such as septic shock, while chronic inflammation has the potential to worsen the condition of body tissues and ultimately lead to significant impairment of their functionality. Although the central nervous system has long been considered immune privileged to peripheral immune responses, recent research has shown that strong immune responses in the periphery also affect the brain, leading to reactive microglia, which belong to the innate immune system and reside in the brain, and neuroinflammation. The inflammatory response is primarily a protective mechanism to defend against pathogens and tissue damage. However, excessive and chronic inflammation can have negative effects on neuronal structure and function. Neuroinflammation underlies the pathogenesis of many neurological and neurodegenerative diseases and can accelerate their progression. Consequently, targeting inflammatory signaling pathways offers potential therapeutic strategies for various neuropathological conditions, particularly Parkinson's and Alzheimer's disease, by curbing inflammation. Here the blood-brain barrier is a major hurdle for potential therapeutic strategies, therefore it would be highly advantageous to foster and utilize brain innate anti-inflammatory mechanisms. The tricarboxylic acid cycle-derived metabolite itaconate is highly upregulated in activated macrophages and has been shown to act as an immunomodulator with anti-inflammatory and antimicrobial functions. Mesaconate, an isomer of itaconate, similarly reduces the inflammatory response in macrophages. Nevertheless, most studies have focused on its esterified forms and its peripheral effects, while its influence on the CNS remained largely unexplored. Therefore, this study investigated the immunomodulatory and therapeutic potential of endogenously synthesized itaconate and its isomer mesaconate in lipopolysaccharide (LPS)-induced neuroinflammatory processes. Our results show that both itaconate and mesaconate reduce LPS-induced neuroinflammation, as evidenced by lower levels of inflammatory mediators, reduced microglial reactivity and a rescue of synaptic plasticity, the cellular correlate of learning and memory processes in the brain. Overall, this study emphasizes that both itaconate and mesaconate have therapeutic potential for neuroinflammatory processes in the brain and are of remarkable importance due to their endogenous origin and production, which usually leads to high tolerance.

T cell-mediated skin-brain axis: Bridging the gap between psoriasis and psychiatric comorbidities

Psoriasis, a chronic inflammatory skin condition, is often accompanied by psychiatric comorbidities such as anxiety, depression, suicidal ideation, and other mental disorders. Psychological disorders may also play a role in the development and progression of psoriasis. The intricate interplay between the skin diseases and the psychiatric comorbidities is mediated by the 'skin-brain axis'. Understanding the mechanisms underlying psoriasis and psychiatric comorbidities can help improve the efficacy of treatment by breaking the vicious cycle of diseases. T cells and related cytokines play a key role in the pathogenesis of psoriasis and psychiatric diseases, and are crucial components of the 'skin-brain axis'. Apart from damaging the blood-brain barrier (BBB) directly, T cells and secreted cytokines could interact with the hypothalamic-pituitary-adrenal axis (HPA axis) and the sympathetic nervous system (SNS) to exacerbate skin diseases or mental disorders. However, few reviews have systematically summarized the roles and mechanisms of T cells in the interaction between psoriasis and psychiatric comorbidities. In this review, we discussed several key T cells and their roles in the 'skin-brain axis', with a focus on the mechanisms underlying the interplay between psoriasis and mental commodities, to provide data that might help develop effective strategies for the treatment of both psoriasis and psychiatric comorbidities.

Ferroptosis in early brain injury after subarachnoid hemorrhage: review of literature

Spontaneous subarachnoid hemorrhage (SAH), mainly caused by ruptured intracranial aneurysms, is a serious acute cerebrovascular disease. Early brain injury (EBI) is all brain injury occurring within 72 h after SAH, mainly including increased intracranial pressure, decreased cerebral blood flow, disruption of the blood-brain barrier, brain edema, oxidative stress, and neuroinflammation. It activates cell death pathways, leading to neuronal and glial cell death, and is significantly associated with poor prognosis. Ferroptosis is characterized by iron-dependent accumulation of lipid peroxides and is involved in the process of neuron and glial cell death in early brain injury. This paper reviews the research progress of ferroptosis in early brain injury after subarachnoid hemorrhage and provides new ideas for future research.

Inhibition of S100A9 alleviates neurogenic pulmonary edema after subarachnoid hemorrhage

BACKGROUND AND PURPOSE

Neurogenic pulmonary edema (NPE) frequently arises as a complication subsequent to subarachnoid hemorrhage (SAH). Heterodimers of S100A8 and S100A9 are commonly formed, thereby initiating an inflammatory reaction through receptor binding on the cell surface. Paquinimod serves as a specific inhibitor of S100A9. The objective of this investigation is to assess the impact of Paquinimod administration and S100A9 knockout on NPE following SAH.

METHODS

In this study, SAH models of C57BL/6J wild-type (WT) and S100A9 knockout mice were established through intravascular perforation. These models were then divided into several groups, including the WT-sham group, S100A9-KO-sham group, WT-SAH group, WT-SAH + Paquinimod group, and S100A9-KO-SAH group. After 24 h of SAH induction, pulmonary edema was assessed using the lung wet-dry weight method and Hematoxylin and eosin (HE) staining. Additionally, the expression levels of various proteins, such as interleukin-1β (IL-1β), tumor necrosis factor α (TNF-α), occludin, claudin-3, Bax, Bcl-2, TLR4, MYD88, and pNF-κB, in lung tissue were analyzed using western blot and immunofluorescence staining. Lung tissue apoptosis was detected by TUNEL staining.

RESULTS

Firstly, our findings indicate that the knockout of S100A9 has a protective effect on early brain injury following subarachnoid hemorrhage (SAH). Additionally, the reduction of brain injury after SAH can also alleviate neurogenic pulmonary edema (NPE). Immunofluorescence staining and western blot analysis revealed that compared to SAH mice with wild-type S100A9 expression (WT-SAH), the lungs of S100A9 knockout SAH mice (S100A9-KO-SAH) and mice treated with Paquinimod exhibited decreased levels of inflammatory molecules (IL-1β and TNF-α) and increased levels of tight junction proteins. Furthermore, the knockout of S100A9 resulted in upregulated expression of the apoptotic-associated protein Bax and down-regulated expression of Bcl-2. Furthermore, a decrease in TLR4, MYD88, and phosphorylated pNF-κB was noted in S100A9-KO-SAH and Paquinimod treated mice, indicating the potential involvement of the TLR4/MYD88/NF-κB signaling pathway in the inhibition of the protective effect of S100A9 on NPE following SAH.

CONCLUSION

The knockout of S100A9 not only ameliorated initial cerebral injury following subarachnoid hemorrhage (SAH), but also mitigated SAH-associated neurogenic pulmonary edema (NPE). Additionally, Paquinimod was found to diminish NPE. These findings imply a correlation between the central nervous system and peripheral organs, highlighting the potential of safeguarding the brain to mitigate harm to peripheral organs.