Role for RIP1 in mediating necroptosis in experimental intracerebral hemorrhage model both in vivo and in vitro

A OHCs-Targeted Strategy for PEDF Delivery in Noise-Induced Hearing Loss

Noise-induced hearing loss (NIHL) results from prolonged exposure to intense noise, causing damage to sensory outer hair cells (OHCs) and spiral ganglion neurons (SGNs). The blood labyrinth barrier (BLB) hinders systemic drug delivery to the inner ear. This study applied a retro-auricular round window membrane (RWM) method to bypass the BLB, enabling the transport of macromolecular proteins into the inner ear. Pigment epithelium-derived factor (PEDF), which has anti-inflammatory and neuroprotective properties, is conjugated to a prestin-targeting peptide 2 (PrTP2) using N-succinimidyl-3-maleimidopropionate (SMP) to form PrTP2-SMP/PEDF. This compound specifically targeted Prestin and accumulated around OHCs for sustained release, effectively reducing OHC and SGN loss. Functional and structural tests, including auditory brainstem response (ABR), confocal microscopy, and scanning electron microscopy (SEM), revealed significant hearing restoration and cellular protection. Additionally, the results of enzyme-linked immunosorbent assay (ELISA), Annexin V and propidium iodide (PI) staining and immunoblotting show that noise exposure may induce pyroptosis in the cochlea by activating the NOD-like receptor protein 3 (NLRP3)-apoptosis-associated speck-like protein containing a CARD (ASC) - cysteinyl aspartate specific proteinase (Caspase-1) pathway and PrTP2-SMP/PEDF alleviates the inflammatory response by inhibiting pyroptosis. Toxicity analysis indicates no adverse effects, suggesting that PrTP2-SMP/PEDF has a promising therapeutic prospective for NIHL.

Targeted Pyroptosis with Resveratrol Nanoparticles to Reduce Secondary Brain Injury and Post-Traumatic Epilepsy

Traumatic brain injury (TBI) is associated with high mortality and disability rates globally, leading to significant sequelae, particularly post-traumatic epilepsy (PTE), which severely impacts physical health and quality of life. TBI involves primary and secondary damage, with the latter exacerbating the initial injury through neuroinflammation, influencing the overall outcome. Recent studies highlight pyroptosis as a crucial factor in the spread of secondary brain damage and the development of epilepsy, making it a vital therapeutic target. While current TBI treatments focus on surgical and medical interventions to reduce intracranial pressure, addressing secondary damage has limited clinical translation, largely due to the blood-brain barrier (BBB) hindering drug accumulation in the affected area. Resveratrol (RV) shows promise as a therapeutic agent due to its anti-inflammatory properties. This study presents a nanoliposome (C-Lips/RV) engineered with cysteine-alanine-glutamine-lysine peptides to enhance RV delivery to the brain, mitigate pyroptosis, and reduce inflammation. In TBI rats, C-Lips/RV demonstrates a longer half-life and effective targeting of brain injury, leading to reduced pyroptosis and PTE, slowed secondary damage progression, and improved functional recovery. This work offers insights into managing secondary brain damage and PTE.

The dual role of microglia in intracerebral hemorrhage

Intracerebral hemorrhage has the characteristics of high morbidity, disability and mortality, which has caused a heavy burden to families and society. Microglia are resident immune cells in the central nervous system, and their activation plays a dual role in tissue damage after intracerebral hemorrhage. The damage in cerebral hemorrhage is embodied in the following aspects: releasing inflammatory factors and inflammatory mediators, triggering programmed cell death, producing glutamate induced excitotoxicity, and destroying blood-brain barrier; The protective effect is reflected in the phagocytosis and clearance of harmful substances by microglia, and the secretion of anti-inflammatory and neurotrophic factors. This article summarizes the function of microglia and its dual regulatory mechanism in intracerebral hemorrhage. In the future, drugs, acupuncture and other clinical treatments can be used to intervene in the activation state of microglia, so as to reduce the harm of microglia.

Ubiquitous regulation of cerebrovascular diseases by ubiquitin-modifying enzymes

Cerebrovascular diseases (CVDs) are a major threat to global health. Elucidation of the molecular mechanisms underlying the pathology of CVDs is critical for the development of efficacious preventative and therapeutic approaches. Accumulating studies have highlighted the significance of ubiquitin-modifying enzymes (UMEs) in the regulation of CVDs. UMEs are a group of enzymes that orchestrate ubiquitination, a post-translational modification tightly involved in CVDs. Functionally, UMEs regulate multiple pathological processes in ischemic and hemorrhagic stroke, moyamoya disease, and atherosclerosis. Considering the important roles of UMEs in CVDs, they may become novel druggable targets for these diseases. Besides, techniques applying UMEs, such as proteolysis-targeting chimera and deubiquitinase-targeting chimera, may also revolutionize the therapy of CVDs in the future.

The role of gut microorganisms and metabolites in intracerebral hemorrhagic stroke: a comprehensive review

Intracerebral hemorrhagic stroke, characterized by acute hemorrhage in the brain, has a significant clinical prevalence and poses a substantial threat to individuals' well-being and productivity. Recent research has elucidated the role of gut microorganisms and their metabolites in influencing brain function through the microbiota-gut-brain axis (MGBA). This article provides a comprehensive review of the current literature on the common metabolites, short-chain fatty acids (SCFAs) and trimethylamine-N-oxide (TMAO), produced by gut microbiota. These metabolites have demonstrated the potential to traverse the blood-brain barrier (BBB) and directly impact brain tissue. Additionally, these compounds have the potential to modulate the parasympathetic nervous system, thereby facilitating the release of pertinent substances, impeding the buildup of inflammatory agents within the brain, and manifesting anti-inflammatory properties. Furthermore, this scholarly analysis delves into the existing dearth of investigations concerning the influence of gut microorganisms and their metabolites on cerebral functions, while also highlighting prospective avenues for future research.

BCL-3 Promotes Intracerebral Hemorrhage Progression by Increasing Blood-Brain Barrier Permeability, Inflammation, and Cell Apoptosis via Endoplasmic Reticulum Stress

Background

Intracerebral hemorrhage (ICH) is among the common types of stroke with high mortality and morbidity. Molecular biomarker selection is crucial for ICH diagnosis and treatment. However, the identification of ICH-related biomarkers remains inadequate.

Materials and Methods

In vivo and in vitro ICH models were generated and transfected with silenced B-cell lymphoma-3 (BCL-3 and siRNA BCL-3), overexpressed BCL-3, and endoplasmic reticulum stress (ERS) agonist (2-CLHA). Hematoxylin-eosin staining and transmission electron microscopy were used to observe the transfected cells. RNA sequencing was performed in vivo on the sham and ICH groups. The blood-brain barrier (BBB) permeability was evaluated by determining Evans blue dye extravasation, transendothelial electrical resistance, and paracellular permeability. Moreover, tight junction-, cell apoptosis-, and endoplasmic reticulum stress- (ERS-) related proteins were evaluated through real-time quantitative PCR, western blotting, immunohistochemistry, and TUNEL staining. The levels of inflammatory cytokines were measured through the enzyme-linked immunosorbent assay.

Results

RNA-seq revealed that BCL-3 acts as a key player. BCL-3 promotes ICH progression by increasing BBB permeability, ERS, inflammation, and cell apoptosis. Silencing of BCL-3 slows ICH progression by reducing BBB permeability and inflammation and terminating cell apoptosis and ERS in vitro and in vivo.

Conclusion

Our study identified ICH biomarkers and elucidated the role of BCL-3 in ICH for the first time.

Annao Pingchong decoction alleviate the neurological impairment by attenuating neuroinflammation and apoptosis in intracerebral hemorrhage rats

ETHNOPHARMACOLOGICAL RELEVANCE

Intracerebral hemorrhage (ICH) is a central nervous system disease that causes severe disability or death. Even though Annao Pingchong decoction (ANPCD), a traditional Chinese decoction, has been used clinically to treat ICH in China, its molecular mechanism remains unclear.

AIM OF THE STUDY

To study whether the neuroprotective effect of ANPCD on ICH rats is achieved by alleviating neuroinflammation. This paper mainly explored whether inflammation-related signaling pathways (HMGB1/TLR4/NF-κB P65) plays a role in ANPCD treatment of ICH rats.

MATERIALS AND METHODS

Liquid chromatography-tandem mass spectrometry was used to analyze the chemical composition of ANPCD. ICH models were established by injecting autologous whole blood into the left caudate nucleus of Sprague-Dawley (SD) rats. Modified neurological severity scoring (mNSS) was used to assess the neurological deficits. The levels of tumor necrosis factor (TNF)-α, interleukin (IL)-1β, and IL-6 were analyzed using enzyme-linked immunosorbent assay (ELISA). Pathological changes in the rat brains were observed using hematoxylin-eosin, Nissl, and TUNEL staining. The protein levels of HMGB1, TLR4, NF-κB p65, B-cell lymphoma 2 (Bcl-2), and Bcl-2-associated X protein (Bax) were measured by western blotting and immunofluorescence analysis.

RESULTS

Ninety-three ANPCD compounds were identified, including 48 active plasma components. Treatment with ANPCD effectively improved the outcome, as observed by the neurological function scores analysis and brain histopathology. Our results showed that ANPCD exerts its anti-inflammatory effects by significantly downregulating the expression of HMGB1, TLR4, NF-κB p65, TNF-α, IL-1β, and IL-6. ANPCD also exerted anti-apoptotic effects by significantly decreasing the apoptosis rate and Bax/Bcl-2 ratio.

CONCLUSION

We found that ANPCD had neuroprotective effect in clinical work. Here, we also found that the action mechanism of ANPCD might be related to attenuate neuroinflammation and apoptosis. These effects were achieved by inhibiting the expression of HMGB1, TLR4 and NF-κB p65.

Induction Mechanism of Ferroptosis, Necroptosis, and Pyroptosis: A Novel Therapeutic Target in Nervous System Diseases

In recent years, three emerging cell deaths, ferroptosis, necroptosis and pyroptosis, have gradually attracted everyone's attention, and they also play an important role in the occurrence and development of various diseases. Ferroptosis is an idiographic iron-dependent form regulated cell death with the hallmark of accumulation of the intracellular reactive oxygen species (ROS). Necroptosis is a form of regulated necrotic cell death mediated by the receptor-interacting protein kinase 1(RIPK1) and receptor-interacting protein kinase 3RIPK3. Pyroptosis, also known as cell inflammatory necrosis, is a programmed cell necrosis mediated by Gasdermin D (GSDMD). It is manifested by the continuous swelling of the cells until the cell membrane ruptures, resulting in the release of the cell contents and the activation of a strong inflammatory response. Neurological disorders remain a clinical challenge and patients do not respond well to conventional treatments. Nerve cell death can aggravate the occurrence and development of neurological diseases. This article reviews the specific mechanisms of these three types of cell death and their relationship with neurological diseases and the evidence for the role of the three types of cell death in neurological diseases; understanding these pathways and their mechanisms is helpful for the treatment of neurological diseases.

Unwinding the modalities of necrosome activation and necroptosis machinery in neurological diseases

Necroptosis, a regulated form of cell death, is involved in the genesis and development of various life-threatening diseases, including cancer, neurological disorders, cardiac myopathy, and diabetes. Necroptosis initiates with the formation and activation of a necrosome complex, which consists of RIPK1, RIPK2, RIPK3, and MLKL. Emerging studies has demonstrated the regulation of the necroptosis cell death pathway through the implication of numerous post-translational modifications, namely ubiquitination, acetylation, methylation, SUMOylation, hydroxylation, and others. In addition, the negative regulation of the necroptosis pathway has been shown to interfere with brain homeostasis through the regulation of axonal degeneration, mitochondrial dynamics, lysosomal defects, and inflammatory response. Necroptosis is controlled by the activity and expression of signaling molecules, namely VEGF/VEGFR, PI3K/Akt/GSK-3β, c-Jun N-terminal kinases (JNK), ERK/MAPK, and Wnt/β-catenin. Herein, we briefly discussed the implication and potential of necrosome activation in the pathogenesis and progression of neurological manifestations, such as Alzheimer's disease, Parkinson's disease, multiple sclerosis, traumatic brain injury, and others. Further, we present a detailed picture of natural compounds, micro-RNAs, and chemical compounds as therapeutic agents for treating neurological manifestations.

GSDMD knockdown exacerbates hippocampal damage and seizure susceptibility by crosstalk between pyroptosis and apoptosis in kainic acid-induced temporal lobe epilepsy

BACKGROUND

Neuronal loss is a vital pathological feature of temporal lobe epilepsy (TLE). However, the exact mechanism of neuronal loss in TLE is not fully understood. Pyroptosis, a novel form of programmed cell death (PCD), has been considered a contributor to the pathogenesis of TLE. However, recent studies have implicated extensive molecular crosstalk among pyroptosis, apoptosis, and necroptosis in various diseases, and they can be transformed to each other according to different contexts. This study aimed to investigate whether gasdermin D (GSDMD)-mediated pyroptosis is involved in the pathogenesis of TLE and whether crosstalk exists in the process of the modulation of pyroptosis.

METHODS

The TLE model was established by intra-amygdala injection of kainic acid. The Racine score and local field potential (LFP) recordings were used to assess seizure severity. Western blotting and immunofluorescence were applied to detect the levels and cellular localization of GSDMD. The neuronal loss and type of neuronal death in the bilateral hippocampus were assessed by Nissl staining and flow cytometry analysis. The underlying crosstalk among pyroptosis, apoptosis, and necroptosis was explored by western blot and verified by VX765.

RESULTS

GSDMD was significantly upregulated and mainly expressed within the neurons of the hippocampus in the TLE model. Inhibition of pyroptosis by GSDMD knockdown triggered caspase-3-mediated apoptosis, leading to excess neuronal loss and deterioration of epileptic behaviors. Blocking caspase-1 markedly inhibited caspase-3-mediated apoptosis and improved epileptic behaviors under GSDMD knockdown.

CONCLUSIONS

Our results demonstrate that GSDMD-mediated pyroptosis is involved in the pathogenesis of TLE. However, inhibition of GSDMD triggers caspase-1-mediated crosstalk between pyroptosis and apoptosis, which exacerbates neuronal loss and seizure susceptibility. Therefore, the complex crosstalk among different forms of PCD should be considered when a potential molecular target in the single PCD pathway is modulated. On the other hand, along with further studies of molecular crosstalk among the PCD pathways, taking advantage of crosstalk to attenuate neuronal loss may provide new insight for the clinical therapy of TLE.

Receptor-interacting protein 3-phosphorylated Ca2+ /calmodulin-dependent protein kinase II and mixed lineage kinase domain-like protein mediate intracerebral hemorrhage-induced neuronal necroptosis

Necroptosis-mediated cell death is an important mechanism in intracerebral hemorrhage (ICH)-induced secondary brain injury (SBI). Our previous study has demonstrated that receptor-interacting protein 1 (RIP1) mediated necroptosis in SBI after ICH. However, further mechanisms, such as the roles of receptor-interacting protein 3 (RIP3), mixed lineage kinase domain-like protein (MLKL), and Ca²⁺ /calmodulin-dependent protein kinase II (CaMK II), remain unclear. We hypothesized that RIP3, MLKL, and CaMK II might participate in necroptosis after ICH, including their phosphorylation. The ICH model was induced by autologous blood injection. First, we found the activation of necroptosis after ICH in brain tissues surrounding the hematoma (propidium iodide staining). Meanwhile, the phosphorylation and expression of RIP3, MLKL, and CaMK II were differently up-regulated (western blotting and immunofluorescent staining). The specific inhibitors could suppress RIP3, MLKL, and CaMK II (GSK'872 for RIP3, necrosulfonamide for MLKL, and KN-93 for CaMK II). We found the necroptosis surrounding the hematoma and the concrete interactions in RIP3-MLKL/RIP3-CaMK II also both decreased after the specific intervention (co-immunoprecipitation). Then we conducted the short-/long-term neurobehavioral tests, and the rats with specific inhibition mostly had better performance. We also found less blood-brain barrier (BBB) injury, and less neuron loss (Nissl staining) in intervention groups, which supported the neurobehavioral tests. Besides, oxidative stress and inflammation were also alleviated with intervention, which had significant less reactive oxygen species (ROS), tumor necrosis factor (TNF)-α, lactate dehydrogenase (LDH), Iba1, and GFAP surrounding the hematoma. These results confirmed that RIP3-phosphorylated MLKL and CaMK II participate in ICH-induced necroptosis and could provide potential targets for the treatment of ICH patients.

The Regulated Cell Death and Potential Interventions in Preterm Infants after Intracerebral Hemorrhage

Intracerebral hemorrhage (ICH) in preterm infants is one of the major co-morbidities of preterm birth and is associated with long-term neurodevelopmental deficits. There are currently no widely accepted treatments to prevent ICH or therapies for the neurological sequelae. With studies broadening the scope of cell death, the newly defined concept of regulated cell death has enriched our understanding of the underlying mechanisms of secondary brain injury after ICH and has suggested potential interventions in preterm infants. In this review, we will summarize the current evidence for regulated cell death pathways in preterm infants after ICH, including apoptosis, necroptosis, pyroptosis, ferroptosis, autophagy, and PANoptosis as well as several potential intervention strategies that may protect the immature brain from secondary injury after ICH through regulating regulated cell death.

Axin1 participates in blood-brain barrier protection during experimental ischemic stroke via phosphorylation at Thr485 in rats

Axin1 takes an important part in a variety of signaling pathway, such as MEKK1, GSK3β, and β-catenin, and plays a variety of physiological functions; but its effects on the brain-blood barrier (BBB) and stroke remain unclear. To explore the effects and underlying mechanisms of Axin1 on the BBB in ischemic stroke, Sprague-Dawley rats were subjected to middle cerebral artery occlusion (MCAO). Human brain microvascular endothelial cells (HBMEC) were subjected to oxygen/glucose deprivation/reoxygenation (OGD/R) to imitate ischemia/reperfusion (I/R) injury. We found that Axin1 was upregulated in HBMEC after OGD without reoxygenation, and downregulated in the injured hemisphere after MCAO without reperfusion. Tight junction (TJ) proteins were upregulated both in HBMEC after OGD without reoxygenation and in ischemic penumbra of the injured hemisphere in rats after MCAO without reperfusion. TJ proteins were downregulated after MCAO/R in rats. Overexpression of Axin1 upregulated the levels of TJ proteins, which alleviated BBB permeability, reduced infarction volume, and ultimately improved neurological behavioral indicators after I/R injury. Furthermore, inhibiting phosphorylation of Axin1 at Thr485 notably increased the expression of Snail and decreased the expression of TJ proteins. Our findings demonstrate that Axin1 participates in BBB protection and improvement of neurological functions during ischemic stroke by regulating TJ proteins. Axin1 may serve as a potential novel candidate to protect BBB and relieve brain injury.

Molecular mechanisms of neuronal death in brain injury after subarachnoid hemorrhage

Subarachnoid haemorrhage (SAH) is a common cerebrovascular disease with high disability and mortality rates worldwide. The pathophysiological mechanisms involved in an aneurysm rupture in SAH are complex and can be divided into early brain injury and delayed brain injury. The initial mechanical insult results in brain tissue and vascular disruption with hemorrhages and neuronal necrosis. Following this, the secondary injury results in diffused cerebral damage in the peri-core area. However, the molecular mechanisms of neuronal death following an aneurysmal SAH are complex and currently unclear. Furthermore, multiple cell death pathways are stimulated during the pathogenesis of brain damage. Notably, particular attention should be devoted to necrosis, apoptosis, autophagy, necroptosis, pyroptosis and ferroptosis. Thus, this review discussed the mechanism of neuronal death and its influence on brain injury after SAH.

Advances in RIPK1 kinase inhibitors

Programmed necrosis is a new modulated cell death mode with necrotizing morphological characteristics. Receptor interacting protein 1 (RIPK1) is a critical mediator of the programmed necrosis pathway that is involved in stroke, myocardial infarction, fatal systemic inflammatory response syndrome, Alzheimer's disease, and malignancy. At present, the reported inhibitors are divided into four categories. The first category is the type I ATP-competitive kinase inhibitors that targets the area occupied by the ATP adenylate ring; The second category is type Ⅱ ATP competitive kinase inhibitors targeting the DLG-out conformation of RIPK1; The third category is type Ⅲ kinase inhibitors that compete for binding to allosteric sites near ATP pockets; The last category is others. This paper reviews the structure, biological function, and recent research progress of receptor interaction protein-1 kinase inhibitors.

Sam50 exerts neuroprotection by maintaining the mitochondrial structure during experimental cerebral ischemia/reperfusion injury in rats

AIM

To investigate the role of Sam50, a barrel protein on the surface of the mitochondrial outer membrane, in cerebral ischemia-reperfusion (I/R) injury and its underlying mechanisms.

METHODS

A middle cerebral artery occlusion/reperfusion (MCAO/R) model in adult male Sprague-Dawley rats was established in vivo, and cultured neurons were exposed to oxygen-glucose deprivation/reoxygenation (OGD/R) to simulate I/R injury in vitro. Lentiviral vector encoding Sam50 or Sam50 shRNA was constructed and administered to rats by intracerebroventricular injection to overexpress and knockdown Sam50, respectively.

RESULTS

First, after MCAO/R induction, the mitochondrial structure was damaged, and Sam50 protein levels were increased responsively both in vivo and in vitro. Then, it was found that Sam50 overexpression could reduce infarction size, inhibit neuronal cell death, improve neurobehavioral disability, protect mitochondrial structure integrity, and ameliorate mitochondrial dysfunction, which was induced by I/R injury both in vivo and in vitro. However, Sam50 downregulation showed the opposite results and aggravated I/R injury by inducing neuronal cell death, neurobehavioral disability, and mitochondrial dysfunction. Moreover, we found that the interaction between Sam50 and Mic19 was broken off after OGD/R, showing that the Sam50-Mic19-Mic60 axis was breakage in neurons, which would be a reason for mitochondrial structure and function abnormalities induced by I/R injury.

CONCLUSION

Sam50 played a vital role in the protection of neurons and mitochondria in cerebral I/R injury, which could be a novel target for mitochondrial protection and ameliorating I/R injury.

An IgM monoclonal antibody against domain 1 of CD147 induces non-canonical RIPK-independent necroptosis in a cell type specific manner in hepatocellular carcinoma cells

CD147/Basigin/EMMPRIN is overexpressed in several cancerous tissues and it has been shown to induce matrix metalloproteinases (MMPs) whose expression is associated with cancer metastasis. Thus, targeting CD147 with monoclonal antibodies (mAbs) potentially has therapeutic applications in cancer immunotherapy. Here, we report the use of anti-CD147 mAbs targeting domain 1 of CD147, namely M6-1D4 (IgM), M6-1F3 (IgM), M6-2F9 (IgM) and M6-1E9 (IgG2a), against several human cancer cell lines. Strikingly, IgM but not IgG mAbs against CD147, especially clone M6-1D4, induced acute cellular swelling, and this phenomenon appeared to be specifically found with hepatocellular carcinoma (HCC) cells. Furthermore, molecular investigation upon treating HepG2 cells with M6-1D4 showed unfolded protein response (UPR) activation, autophagosome accumulation, and cell cycle arrest, but without classic apoptosis related features. More interestingly, prolonged M6-1D4 treatment (24 h) resulted in irreversible oncosis leading to necroptosis. Furthermore, treatment with a mixed lineage kinase domain-like psuedokinase (MLKL) inhibitor and partial knockout of MLKL resulted in reduced sensitivity to necroptosis in M6-1D4-treated HepG2 cells. Surprisingly however, the observed necroptotic signaling axis appeared to be non-canonical as it was independent of receptor-interacting serine/threonine-protein kinase (RIPK) phosphorylation. In addition, no cytotoxic effect on human dermal fibroblast (HDF) was observed after incubation with M6-1D4. Taken together, this study provides clues to target CD147 in HCC using mAbs, as well as sheds new light on a novel strategy to kill cancerous cells by the induction of necroptosis.

Neuroprotection by Trans-Resveratrol in Rats With Intracerebral Hemorrhage: Insights into the Role of Adenosine A1 Receptors

Given the neuroprotective effects of trans-resveratrol (RV), this study aimed to investigate the involvement of the adenosine A1 receptor (A1R) in RV-mediated neuroprotection in a rat intracerebral hemorrhage (ICH) model induced by intrastriatal injection of collagenase. Rats were divided into 5 groups: (1) control, (2) sham-operated, (3) ICH pretreated with vehicle, (4) ICH pretreated with RV, and (5) ICH pretreated with RV and the A1R antagonist DPCPX. At 48 hours after ICH, the rats were subjected to neurological testing. Brain tissues were assessed for neuronal density and morphological features using routine and immunohistochemical staining. Expression of tumor necrosis factor-α (TNF-α), caspase-3, and RIPK3 proteins was examined using ELISA. A1R, MAPK P38, Hsp90, TrkB, and BDNF genes were examined using RT-qPCR. RV protected against neurological deficits and neuronal depletion, restored the expression of TNF-α, CASP3, RIPK3, A1R, and Hsp90, and increased BDNF/TrkB. DPCPX abolished the effects of RV on neurological outcomes, neuronal density, CASP3, RIPK3, A1R, Hsp90, and BDNF. These data indicate that the neuroprotection by RV involves A1R and inhibits CASP3-dependent apoptosis and RIPK3-dependent necroptosis in the perihematoma region; this is likely to be mediated by crosstalk between A1R and the BDNF/TrkB pathway.

Necrosulfonamide Alleviates Acute Brain Injury of Intracerebral Hemorrhage via Inhibiting Inflammation and Necroptosis

Objective

Intracerebral hemorrhage (ICH) is the most lethal subtype of stroke, without effective treatment. Necrosulfonamide (NSA), a specific inhibitor for mixed lineage kinase domain-like protein, has been reported to exert neuroprotective effects in neurological diseases by ameliorating neuroinflammation and necroptosis. We hypothesized that NSA would alleviate acute brain injury and improve behavioral outcomes after ICH.

Materials and Methods

Male adult C57BL/6 mice were assigned randomly into three groups. In vehicle and treatment groups, animals were injected with collagenase VII to induce ICH. The solvent (0.25% DMSO) and NSA (5 mg/kg) were administrated intraperitoneally twice a day, respectively. The sham group was injected with saline and administrated with DMSO. The brain hematoma volume, inflammatory factors, and blood-brain barrier permeability were measured on day 3 after the operation. Fluorescent double immunostaining was performed to evaluate the neuronal death. Neurological functions were assessed.

Results

In the NSA group, the hematoma size was significantly reduced, inflammatory cells and cytokines were suppressed, and the blood-brain barrier was protected compared to vehicle controls. NSA dramatically reduced the death of neurons and improved the performance of neurological functions after ICH.

Conclusion

Necrosulfonamide has a neuroprotective role in alleviating acute brain injury in a mouse ICH model, and this is associated with reduced neuroinflammation and necroptosis.

Role and Mechanism of Ferroptosis in Neurological Diseases

Background

Ferroptosis, as a new form of cell death, is different from other cell deaths such as autophagy or senescence. Ferroptosis involves in the pathophysiological progress of several diseases, including cancers, cardiovascular diseases, nervous system diseases, and kidney damage. Since oxidative stress and iron deposition are the broad pathological features of neurological diseases, the role of ferroptosis in neurological diseases has been widely explored.

Scope of review

Ferroptosis is mainly characterized by changes in iron homeostasis, iron-dependent lipid peroxidation, and glutamate toxicity accumulation, of which can be specifically reversed by ferroptosis inducers or inhibitors. The ferroptosis is mainly regulated by the metabolism of iron, lipids and amino acids through System Xc⁻, voltage-dependent anion channels, p53, p62-Keap1-Nrf2, mevalonate and other pathways. This review also focus on the regulatory pathways of ferroptosis and its research progress in neurological diseases.

Major conclusions

The current researches of ferroptosis in neurological diseases mostly focus on the key pathways of ferroptosis. At the same time, ferroptosis was found playing a bidirectional regulation role in neurological diseases. Therefore, the specific regulatory mechanisms of ferroptosis in neurological diseases still need to be further explored to provide new perspectives for the application of ferroptosis in the treatment of neurological diseases.

Modes of Brain Cell Death Following Intracerebral Hemorrhage

Intracerebral hemorrhage (ICH) is a devastating form of stroke with high rates of mortality and morbidity. It induces cell death that is responsible for neurological deficits postinjury. There are no therapies that effectively mitigate cell death to treat ICH. This review aims to summarize our knowledge of ICH-induced cell death with a focus on apoptosis and necrosis. We also discuss the involvement of ICH in recently described modes of cell death including necroptosis, pyroptosis, ferroptosis, autophagy, and parthanatos. We summarize treatment strategies to mitigate brain injury based on particular cell death pathways after ICH.

Hydrogen-rich saline alleviates early brain injury through inhibition of necroptosis and neuroinflammation via the ROS/HO-1 signaling pathway after traumatic brain injury

Traumatic brain injury (TBI) has been recognized as a serious public health issue and a key contributor to disability and death, with a huge economic burden worldwide. Hydrogen, which is a slight and specific cytotoxic oxygen radical scavenger, has been demonstrated to ameliorate early brain injury (EBI) through reactive oxygen species (ROS), oxidative stress injury, apoptosis and necroptosis. Necroptosis refers to a type of programmed cell death process that has a vital function in neuronal cell death following TBI. The specific function of necroptosis in hydrogen-mediated neuroprotection after TBI, however, has yet to be determined. The present study aimed to examine the neuroprotective effects and possible molecular basis that underly hydrogen-rich saline in TBI-stimulated EBI by examining neural necroptosis in the C57BL/6 mouse model. The brain water content, neurological score, neuroinflammatory cytokines (NF-κΒ, TNF-α, IL-6 and IL-1β) and ROS were evaluated using flow cytometry. Malondialdehyde, superoxide dismutase (SOD) and glutathione (GSH) levels were evaluated using a biochemical kit. Receptor-interacting protein kinase (RIP)1, RIP3, Nrf2 and Heme oxygenase-1 (HO-1) were evaluated using western blotting. mRNA of Nrf2 and HO-1 were evaluated using quantitative PCR. Neuronal death was evaluated by TUNEL staining. The outcomes illustrated that hydrogen-rich saline treatment considerably enhanced the neurological score, increased neuronal survival, decreased the levels of serum MDA and brain ROS, increased the levels of serum GSH and SOD. In addition the protein expression levels of RIP1 and RIP3 and the cytokines NF-κB, TNF-α, IL-1β and IL-6 were downregulated compared with the TBI group, which demonstrated that hydrogen-rich saline-induced inhibition of necroptosis and neuroinflammation ameliorated neuronal death following TBI. The neuroprotective capacity of hydrogen-rich saline was demonstrated to be partly dependent on the ROS/heme oxygenase-1 signaling pathway. Taken together, the findings of the present study indicated that hydrogen-rich saline enhanced neurological outcomes in mice and minimized neuronal death by inducing protective effects against neural necroptosis as well as neuroinflammation.

Ulinastatin alleviates early brain injury after intracerebral hemorrhage by inhibiting necroptosis and neuroinflammation via MAPK/NF-κB signaling pathway

Purpose:

Spontaneous intracerebral hemorrhage (ICH) is a major public health problem with a huge economic burden worldwide. Ulinastatin (UTI), a serine protease inhibitor, has been reported to be anti-inflammatory, immune regulation, and organ protection by reducing reactive oxygen species production, and inflammation. Necroptosis is a programmed cell death mechanism that plays a vital role in neuronal cell death after ICH. However, the neuroprotection of UTI in ICH has not been confirmed, and the potential mechanism is unclear. The present study aimed to investigate the neuroprotection and potential molecular mechanisms of UTI in ICH-induced EBI in a C57BL/6 mouse model.

Methods:

The neurological score, brain water content, neuroinflammatory cytokine levels, and neuronal damage were evaluated. The anti-inflammation effectiveness of UTI in ICH patients also was evaluated.

Results:

UTI treatment markedly increased the neurological score, alleviate the brain edema, decreased the inflammatory cytokine TNF-α, interleukin‑1β (IL‑1β), IL‑6, NF‑κB levels, and RIP1/RIP3, which indicated that UTI-mediated inhibition of neuroinflammation, and necroptosis alleviated neuronal damage after ICH. UTI also can decrease the inflammatory cytokine of ICH patients. The neuroprotective capacity of UTI is partly dependent on the MAPK/NF-κB signaling pathway.

Conclusions:

UTI improves neurological outcomes in mice and reduces neuronal death by protecting against neural neuroinflammation, and necroptosis.

The neuroprotection of cerebrolysin after spontaneous intracerebral hemorrhage through regulates necroptosis via Akt/ GSK3β signaling pathway

PURPOSE

Spontaneous intracerebral hemorrhage (ICH) is a major cause of death and disability with a huge economic burden worldwide. Cerebrolysin (CBL) has been previously used as a nootropic drug. Necroptosis is a programmed cell death mechanism that plays a vital role in neuronal cell death after ICH. However, the precise role of necroptosis in CBL neuroprotection following ICH has not been confirmed.

METHODS

In the present study, we aimed to investigate the neuroprotective effects and potential molecular mechanisms of CBL in ICH-induced early brain injury (EBI) by regulating neural necroptosis in the C57BL/6 mice model. Mortality, neurological score, brain water content, and neuronal death were evaluated by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining, Evans blue extravasation, Western blotting, and quantitative real-time polymerase chain reaction (PCR).

RESULTS

The results show that CBL treatment markedly increased the survival rate, neurological score, and neuron survival, and downregulated the protein expression of RIP1 and RIP3, which indicated that CBL-mediated inhibition of necroptosis, and ameliorated neuronal death after ICH. The neuroprotective capacity of CBL is partly dependent on the Akt/GSK3β signaling pathway.

CONCLUSIONS

CBL improves neurological outcomes in mice and reduces neuronal death by protecting against neural necroptosis.

RIPK3-Dependent Necroptosis Activates MCP-1-Mediated Inflammation in Mice after Intracerebral Hemorrhage

BACKGROUND

Recent studies have reported that receptor-interacting protein kinase 3 (RIPK3)-dependent necroptosis is related to the pathological process of intracerebral hemorrhage (ICH). Some studies support the view that inhibiting necroptosis is a key mechanism preventing inflammation. Inflammation is a crucial factor contributing to neurological injuries and unfavorable outcomes after ICH. The aim of this study was to clarify the association between necroptosis and monocyte chemoattractant protein-1 (MCP-1)-mediated inflammation and identify a new target for the treatment of ICH.

METHODS

An ICH model was established in C57BL/6 mice by injecting collagenase IV into the right basal ganglia. The RIPK3 inhibitor GSK872 was administered through intraventricular injection. Then, we assessed brain edema and neurobehavioral function. Western blotting was employed to detect changes in RIPK3, phospho-mixed lineage kinase domain-like protein (p-MLKL), MCP-1, phospho-c-Jun N-terminal kinase (p-JNK) and interleukin 6 (IL-6) levels in the brain tissue. The localization of RIPK3 and MCP-1 was observed using immunofluorescence staining. Co-immunoprecipitation was performed to determine the interaction between RIPK3 and MCP-1.

RESULTS

Compared with the sham group, the levels of RIPK3, p-MLKL, MCP-1, p-JNK and IL-6 were increased post-ICH. GSK872 pretreatment significantly reduced RIPK3, p-MLKL, MCP-1, p-JNK and IL-6 expression, accompanied by mitigated cerebral edema and neurobehavioral defects. RIPK3 and MCP-1 colocalized in the perinuclear region after ICH. We detected the formation of the RIPK3-MCP-1 complex in ICH brain tissue.

CONCLUSIONS

There exerted an association between RIPK3 and MCP-1. The inhibition of RIPK3 alleviated MCP-1-mediated inflammation following 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.

Fraxinellone ameliorates intracerebral hemorrhage-induced secondary brain injury by regulating Krüppel-like transcription factor 2 expression in rats

Damage to the blood-brain barrier (BBB) is an important factor leading to intracerebral hemorrhage (ICH)-induced secondary brain injury (SBI). Krüppel-like transcription factor 2 (KLF2) plays an important role in the maintenance of the BBB. This study aims to detect the changes of KLF2 after ICH and evaluate the potential effects of fraxinellone on ICH-induced SBI and its correlation with KLF2. An ICH model was established by injecting autologous blood into the right basal ganglia of Sprague-Dawley (SD) rats. First, after ICH induction, the protein levels of KLF2 were reduced. Then, we found that the decrease of KLF2 protein levels induced by ICH could be effectively reversed with the treatment of fraxinellone in vascular endothelial cells. Furthermore, fraxinellone treatment effectively alleviated brain edema, decreased the levels of TNF-α and IL-1β, and improved neuronal cell degeneration induced by ICH. Meanwhile, fraxinellone ameliorated neurobehavioral disorders, motor and sensory impairments, and neurobehavioral disorders and memory loss caused by ICH. Collectively, these findings reveal that KLF2 may be a potential target for fraxinellone to exert neuroprotective effects after ICH, and fraxinellone could be a potential therapeutic agent for SBI after ICH.

Emerging immune and cell death mechanisms in stroke: Saponins as therapeutic candidates

The complexity of the ischemic cascade is based on the integrated crosstalk of every cell type in the neurovascular unit. Depending on the features of the ischemic insult, several cell death mechanisms are triggered, such as apoptosis, necroptosis, ferroptosis/oxytosis, ETosis or pyroptosis, leading to reactive astrogliosis. However, emerging evidence demonstrates a dual role for the immune system in stroke pathophysiology, where it exerts both detrimental and also beneficial functions. In this review, we discuss the relevance of several cell death modalities and the dual role of the immune system in stroke pathophysiology. We also provide an overview of some emerging immunomodulatory therapeutic strategies, amongst which saponins, which are promising candidates that exert multiple pharmacological effects.

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Several cell death mechanisms coexist in stroke pathophysiology.

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Neurons are more vulnerable to necroptosis than glial cells.

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Inhibitors of receptor-interacting protein kinases and of ferroptosis induce neuroprotection.

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Saponins exert modulatory effects on inflammation and neuronal cell death in stroke.

Metformin ameliorates neuronal necroptosis after intracerebral hemorrhage by activating AMPK

BACKGROUND

Intracerebral hemorrhage (ICH) is a major cause of death and disability globally. As a type of secondary injury after ICH, treatment for cell death can promote the recovery of neurological function.

METHODS

Among all the cell death, neuronal necroptosis has recently been demonstrated of significance in the pathogenesis of ICH. However, the administration of drugs against necroptosis has many limitations.

RESULTS

In the present study, we found that metformin, a first-line medication for the treatment of type 2 diabetes, can effectively inhibit neuronal necroptosis after ICH through activating AMPK related pathway, thereby significantly improving neurological function scores and reducing brain edema.

CONCLUSION

These results will provide a new perspective for future research in necroptosis.

Perampanel, an AMPAR antagonist, alleviates experimental intracerebral hemorrhage‑induced brain injury via necroptosis and neuroinflammation

Spontaneous intracerebral hemorrhage (ICH) is a subtype of stroke with high mortality and morbidity due to the lack of effective therapies. The alpha‑amino‑3‑hydroxy‑5‑methyl‑4‑isoxazolepropionic acid receptor antagonist perampanel has been reported to alleviate early brain injury following subarachnoid hemorrhage and traumatic brain injury by reducing reactive oxygen species, apoptosis, autophagy, and necroptosis. Necroptosis is a caspase‑independent programmed cell death mechanism that serves a vital role in neuronal cell death following ICH. However, the precise role of necroptosis in perampanel‑mediated neuroprotection following ICH has not been confirmed. The present study aimed to investigate the neuroprotective effects and potential molecular mechanisms of perampanel in ICH‑induced early brain injury by regulating neural necroptosis in C57BL/6 mice and in a hemin‑induced neuron damage cell culture model. Mortality, neurological score, brain water content, and neuronal death were evaluated. The results demonstrated that perampanel treatment increased the survival rate and neurological score, and increased neuron survival. In addition, perampanel treatment downregulated the protein expression levels of receptor interacting serine/threonine kinase (RIP) 1, RIP3, and mixed lineage kinase domain like pseudokinase, and of the cytokines IL‑1β, IL‑6, TNF‑α, and NF‑κB. These results indicated that perampanel‑mediated inhibition of necroptosis and neuroinflammation ameliorated neuronal death in vitro and in vivo following ICH. The neuroprotective capacity of perampanel was partly dependent on the PTEN pathway. Taken together, the results of the present study demonstrated that perampanel improved neurological outcomes in mice and reduced neuronal death by protecting against neural necroptosis and neuroinflammation.

Necroptosis: A Novel Pathway in Neuroinflammation

Neuroinflammation is a complex inflammatory process in the nervous system that is expected to play a significant role in neurological diseases. Necroptosis is a kind of necrosis that triggers innate immune responses by rupturing dead cells and releasing intracellular components; it can be caused by Toll-like receptor (TLR)-3 and TLR-4 agonists, tumor necrosis factor (TNF), certain microbial infections, and T cell receptors. Necroptosis signaling is modulated by receptor-interacting protein kinase (RIPK) 1 when the activity of caspase-8 becomes compromised. Activated death receptors (DRs) cause the activation of RIPK1 and the RIPK1 kinase activity-dependent formation of an RIPK1-RIPK3-mixed lineage kinase domain-like protein (MLKL), which is complex II. RIPK3 phosphorylates MLKL, ultimately leading to necrosis through plasma membrane disruption and cell lysis. Current studies suggest that necroptosis is associated with the pathogenesis of neuroinflammatory diseases, such as Alzheimer’s disease, Parkinson’s disease, and traumatic brain injury. Inhibitors of necroptosis, such as necrostatin-1 (Nec-1) and stable variant of Nec (Nec-1s), have been proven to be effective in many neurological diseases. The purpose of this article is to illuminate the mechanism underlying necroptosis and the important role that necroptosis plays in neuroinflammatory diseases. Overall, this article shows a potential therapeutic strategy in which targeting necroptotic factors may improve the pathological changes and clinical symptoms of neuroinflammatory disorders.

Cell-specific activation of RIPK1 and MLKL after intracerebral hemorrhage in mice

Receptor-interacting protein kinase-1 (RIPK1) is a master regulator of cell death and inflammation, and mediates programmed necrosis (necroptosis) via mixed-lineage kinase like (MLKL) protein. Prior studies in experimental intracerebral hemorrhage (ICH) implicated RIPK1 in the pathogenesis of neuronal death and cognitive outcome, but the relevant cell types involved and potential role of necroptosis remain unexplored. In mice subjected to autologous blood ICH, early RIPK1 activation was observed in neurons, endothelium and pericytes, but not in astrocytes. MLKL activation was detected in astrocytes and neurons but not endothelium or pericytes. Compared with WT controls, RIPK1 kinase-dead (RIPK1^D138N/D138N) mice had reduced brain edema (24 h) and blood-brain barrier (BBB) permeability (24 h, 30 d), and improved postinjury rotarod performance. Mice deficient in MLKL (Mlkl^-/-) had reduced neuronal death (24 h) and BBB permeability at 24 h but not 30d, and improved post-injury rotarod performance vs. WT. The data support a central role for RIPK1 in the pathogenesis of ICH, including cell death, edema, BBB permeability, and motor deficits. These effects may be mediated in part through the activation of MLKL-dependent necroptosis in neurons. The data support development of RIPK1 kinase inhibitors as therapeutic agents for human ICH.

Activated Microglia Exosomes Mediated miR-383-3p Promotes Neuronal Necroptosis Through Inhibiting ATF4 Expression in Intracerebral Hemorrhage

Intracerebral hemorrhage (ICH) is the second largest type of stroke, with high mortality and morbidity, and most patients have severe sequelae. Brain injury induced by ICH includes primary damage and secondary damage, and the secondary brain injury is the main reason of neurological impairment. The hallmark of secondary brain injury is cell death. Necroptosis is a type of the cell death and plays vital roles in various neurological diseases, but the roles of necroptosis in ICH are still not fully known. Microglia cell is the type of immune cell, plays protective roles in nerve damage and modulates the activity of neurons through secreting exosomes. Exosome-contained miRNAs are also involved in the regulating neuronal activity. However, the roles and the mechanisms of microglia-secreted exosomes miRNAs in ICH neurons necroptosis need to further explore. In this study, ICH model was construct in rats and cells. Injury of cells in brain was detected by PI staining. Necroptosis in rats and cells was detected by western blot and flow cytometry. The expression of miR-383-3p was detected by RT-qPCR. The roles of activated microglia-secreted exosomes and exosome-contained miR-383-3p were detected through co-culturing medium or exosomes with neurons. The target gene of miR-383-3p was determined by luciferase assay and the expression of target gene was detected by western blot. Rescue experiments were used to confirm the mechanism of miR-383-3p in neurons necroptosis. The miR-383-3p role was verified in vivo through injecting miR-383-3p mimic into ICH rats. Here, we found that the necroptosis of neurons was increased in ICH rats through detecting the expression of RIP1 and RIP3 and PI staining. Microglia that activated by ICH promote neurons necroptosis through secreting exosomes and transferring miR-383-3p into neurons. In mechanism, miR-383-3p negatively regulated the expression of ATF4 and then promoted the necroptosis of neurons. Overall, our results provide a novel molecular basis to neurons necroptosis in ICH and may provide a new strategy to retard the secondary brain injury of ICH.

Intracerebral Injection of Heme Induces Lipid Peroxidation, Neuroinflammation, and Sensorimotor Deficits

[Figure: see text].

Rbfox-1 contributes to CaMKIIα expression and intracerebral hemorrhage-induced secondary brain injury via blocking micro-RNA-124

RNA-binding protein fox-1 homolog 1 (Rbfox-1), an RNA-binding protein in neurons, is thought to be associated with many neurological diseases. To date, the mechanism on which Rbfox-1 worsens secondary cell death in ICH remains poorly understood. In this study, we aimed to explore the role of Rbfox-1 in intracerebral hemorrhage (ICH)-induced secondary brain injury (SBI) and to identify its underlying mechanisms. We found that the expression of Rbfox-1 in neurons was significantly increased after ICH, which was accompanied by increases in the binding of Rbfox-1 to Ca²⁺/calmodulin-dependent protein kinase II (CaMKIIα) mRNA and the protein level of CaMKIIα. In addition, when exposed to exogenous upregulation or downregulation of Rbfox-1, the protein level of CaMKIIα showed a concomitant trend in brain tissue, which further suggested that CaMKIIα is a downstream-target protein of Rbfox-1. The upregulation of both proteins caused intracellular-Ca²⁺ overload and neuronal degeneration, which exacerbated brain damage. Furthermore, we found that Rbfox-1 promoted the expression of CaMKIIα via blocking the binding of micro-RNA-124 to CaMKIIα mRNA. Thus, Rbfox-1 is expected to be a promising therapeutic target for SBI after ICH.

Neurovascular Units and Neural-Glia Networks in Intracerebral Hemorrhage: from Mechanisms to Translation

Intracerebral hemorrhage (ICH), the most lethal type of stroke, often leads to poor outcomes in the clinic. Due to the complex mechanisms and cell-cell crosstalk during ICH, the neurovascular unit (NVU) was proposed to serve as a promising therapeutic target for ICH research. This review aims to summarize the development of pathophysiological shifts in the NVU and neural-glia networks after ICH. In addition, potential targets for ICH therapy are discussed in this review. Beyond cerebral blood flow, the NVU also plays an important role in protecting neurons, maintaining central nervous system (CNS) homeostasis, coordinating neuronal activity among supporting cells, forming and maintaining the blood-brain barrier (BBB), and regulating neuroimmune responses. During ICH, NVU dysfunction is induced, along with neuronal cell death, microglia and astrocyte activation, endothelial cell (EC) and tight junction (TJ) protein damage, and BBB disruption. In addition, it has been shown that certain targets and candidates can improve ICH-induced secondary brain injury based on an NVU and neural-glia framework. Moreover, therapeutic approaches and strategies for ICH are discussed.

Acupuncture Ameliorates Neuronal Cell Death, Inflammation, and Ferroptosis and Downregulated miR-23a-3p After Intracerebral Hemorrhage in Rats

Baihui-penetrating-Qubin acupuncture is frequently used to treat intracerebral hemorrhage (ICH) in China. Acupuncture affects multiple microRNAs in diseases. MicroRNA-23a-3p (miR-23a-3p) has been demonstrated to be up-regulated in ICH patients. Herein, the effect of Baihui-penetrating-Qubin acupuncture on miR-23a-3p expression after ICH and the role of miR-23a-3p in ICH were discussed. A rat model of ICH was induced by infusing autologous blood into caudate nucleus. Acupuncture was performed after ICH once a day for 30 min. After 3 consecutive days of acupuncture, the neurobehavioral function, brain edema, neuronal cell death, inflammation, ferroptosis, nuclear factor E2-like 2 (NFE2L2) signaling and miR-23a-3p levels in brain tissues were analyzed. Additionally, antagomiR-23a-3p was injected into rats 3 days prior to ICH modeling to analyze the function of miR-23a-3p in neuronal cell death, inflammation, ferroptosis, and NFE2L2 signaling. Acupuncture relieved the ICH-induced neurological function deficits, increases in brain water content and Fluoro-Jade B (FJB)-positive cells and release of proinflammatory cytokines. Acupuncture also alleviated ferroptosis and decreased miR-23a-3p expression, as evidenced by the increased NFE2L2 nuclear translocation and expressions of heme oxygenase-1 and glutathione peroxidase 4 and the decreased iron and malondialdehyde contents and reactive oxygen species accumulation. Additionally, antagomiR-23a-3p inhibited the ICH-induced increases in FJB-positive cells, release of proinflammatory cytokines, ferroptosis, and promoted NFE2L2 activation. Notably, the binding site of miR-23a-3p existed in NFE2L2. Taken together, acupuncture may alleviate the neuronal cell death, inflammation, and ferroptosis after ICH by down-regulating miR-23a-3p. This study provides a potential mechanism underlying the Baihui-penetrating-Qubin acupuncture improving the early injury after ICH.

The Effect of Melatonin Modulation of Non-coding RNAs on Central Nervous System Disorders: An Updated Review

Melatonin is a hormone produced in and secreted by the pineal gland. Besides its role in regulating circadian rhythms, melatonin has a wide range of protective functions in the central nervous system (CNS) disorders. The mechanisms underlying this protective function are associated with the regulatory effects of melatonin on related genes and proteins. In addition to messenger ribonucleic acid (RNA) that can be translated into protein, an increasing number of non-coding RNAs in the human body are proven to participate in many diseases. This review discusses the current progress of research on the effects of melatonin modulation of non-coding RNAs (ncRNAs), including microRNA, long ncRNA, and circular RNA. The role of melatonin in regulating common pathological mechanisms through these ncRNAs is also summarized. Furthermore, the ncRNAs, currently shown to be involved in melatonin signaling in CNS diseases, are discussed. The information compiled in this review will open new avenues for future research into melatonin mechanisms and provide a further understanding of ncRNAs in the CNS.

A Multi-Model Pipeline for Translational Intracerebral Haemorrhage Research

Apart from acute and chronic blood pressure lowering, we have no specific medications to prevent intracerebral haemorrhage (ICH) or improve outcomes once bleeding has occurred. One reason for this may be related to particular limitations associated with the current pre-clinical models of ICH, leading to a failure to translate into the clinic. It would seem that a breakdown in the 'drug development pipeline' currently exists for translational ICH research which needs to be urgently addressed. Here, we review the most commonly used pre-clinical models of ICH and discuss their advantages and disadvantages in the context of translational studies. We propose that to increase our chances of successfully identifying new therapeutics for ICH, a bi-directional, 2- or 3-pronged approach using more than one model species/system could be useful for confirming key pre-clinical observations. Furthermore, we highlight that post-mortem/ex-vivo ICH patient material is a precious and underused resource which could play an essential role in the verification of experimental results prior to consideration for further clinical investigation. Embracing multidisciplinary collaboration between pre-clinical and clinical ICH research groups will be essential to ensure the success of this type of approach in the future.

CHIP as a therapeutic target for neurological diseases

Carboxy-terminus of Hsc70-interacting protein (CHIP) functions both as a molecular co-chaperone and ubiquitin E3 ligase playing a critical role in modulating the degradation of numerous chaperone-bound proteins. To date, it has been implicated in the regulation of numerous biological functions, including misfolded-protein refolding, autophagy, immunity, and necroptosis. Moreover, the ubiquitous expression of CHIP in the central nervous system suggests that it may be implicated in a wide range of functions in neurological diseases. Several recent studies of our laboratory and other groups have highlighted the beneficial role of CHIP in the pathogenesis of several neurological diseases. The objective of this review is to discuss the possible molecular mechanisms that contribute to the pathogenesis of neurological diseases in which CHIP has a pivotal role, such as stroke, intracerebral hemorrhage, Alzheimer's disease, Parkinson's disease, and polyglutamine diseases; furthermore, CHIP mutations could also cause neurodegenerative diseases. Based on the available literature, CHIP overexpression could serve as a promising therapeutic target for several neurological diseases.

TMEM175 mediates Lysosomal function and participates in neuronal injury induced by cerebral ischemia-reperfusion

As the main organelles for the clearance of damaged proteins and damaged organelles, the function of lysosomes is crucial for maintaining the intracellular homeostasis of long-lived neurons. A stable acidic environment is essential for lysosomes to perform their functions. TMEM175 has been identified as a new K⁺ channel that is responsible for regulating lysosomal membrane potential and pH stability in neurons. This study aimed to understand the role of TMEM175 in lysosomal function of neurons and neuronal injury following cerebral ischemia-reperfusion (I/R). A middle-cerebral-artery occlusion/reperfusion (MCAO/R) model was established in adult male Sprague-Dawley rats in vivo, and cultured neurons were exposed to oxygen-glucose deprivation/reoxygenation (OGD/R) to mimic ischemia-reperfusion (I/R) injury in vitro. We found that the protein level of TMEM175 decreased after cerebral I/R injury and that TMEM175 overexpression ameliorated MCAO/R-induced brain-cell death and neurobehavioral deficits in vivo. Furthermore, these results were recapitulated in cultured neurons. Acridine orange (AO) staining, as well as LysoSensor Green DND-189, cathepsin-B (CTSB), and cathepsin-D (CTSD) activities, showed that TMEM175 deficiency inhibited the hydrolytic function of lysosomes by affecting lysosomal pH. In contrast, TMEM175 upregulation reversed OGD/R-induced lysosomal dysfunction and impaired mitochondrial accumulation in cultured neurons. TMEM175 deficiency induced by cerebral I/R injury leads to compromised lysosomal pH stability, thus inhibiting the hydrolytic function of lysosomes. Consequently, lysosomal-dependent degradation of damaged mitochondria is suppressed and thereby exacerbates brain damage. Exogenous up-regulation of TMEM175 protein level could reverse the neuronal lysosomal dysfunction after ischemia-reperfusion.

TMEM16F Aggravates Neuronal Loss by Mediating Microglial Phagocytosis of Neurons in a Rat Experimental Cerebral Ischemia and Reperfusion Model

Cerebral ischemia is a severe, acute condition, normally caused by cerebrovascular disease, and results in high rates of disability, and death. Phagoptosis is a newly recognized form of cell death caused by phagocytosis of viable cells, and has been reported to contribute to neuronal loss in brain tissue after ischemic stroke. Previous data indicated that exposure of phosphatidylserine to viable neurons could induce microglial phagocytosis of such neurons. Phosphatidylserine can be reversibly exposed to viable cells as a result of a calcium-activated phospholipid scramblase named TMEM16F. TMEM16F-mediated phospholipid scrambling on platelet membranes is critical for hemostasis and thrombosis, which plays an important role in Scott syndrome and has been confirmed by much research. However, few studies have investigated the association between TMEM16F and phagocytosis in ischemic stroke. In this study, a middle-cerebral-artery occlusion/reperfusion (MCAO/R) model was used in adult male Sprague-Dawley rats in vivo, and cultured neurons were exposed to oxygen-glucose deprivation/reoxygenation (OGD/R) to simulate cerebral ischemia-reperfusion (I/R) injury in vitro. We found that the protein level of TMEM16F was significantly increased at 12 h after I-R injury both in vivo and in vitro, and reversible phosphatidylserine exposure was confirmed in neurons undergoing I/R injury in vitro. Additionally, we constructed a LV-TMEM16F-RNAi transfection system to suppress the expression of TMEM16F during and after cerebral ischemia. As a result, TMEM16F knockdown alleviated motor function injury and decreased the microglial phagocytosis of viable neurons in the penumbra through inhibiting the “eat-me” signal phosphatidylserine. Our data indicate that reducing neuronal phosphatidylserine-exposure via deficiency of TMEM16F blocks phagocytosis of neurons and rescues stressed-but-still-viable neurons in the penumbra, which may contribute to reducing infarct volume and improving functional recovering.

Activated WNK3 induced by intracerebral hemorrhage deteriorates brain injury maybe via WNK3/SPAK/NKCC1 pathway

BACKGROUND

Intracerebral hemorrhage (ICH) is the common brain diseases in middle-aged and elderly people, with high disability and/or mortality rate, and is a serious public health concern. Both WNK3 kinase and the WNK3/SPAK/NKCC1 signaling pathway play an integral role in maintaining normal cell homeostasis. However, their role and underlying mechanisms in ICH-induced secondary brain injury (SBI) have yet to be elucidated.

METHODS

We established an ICH model using male Sprague-Dawley (SD) rats by injecting autologous arterial blood into the unilateral basal ganglia. To establish ICH model in vitro, oxyhemoglobin (OxyHb; 20 μM) and neurons were cultured for 6 h at 37 °C, 5% CO₂ atmosphere. To investigate the role of WNK3 and the WNK3/SPAK/NKCC1 signaling pathway in SBI, after genetic interventions, rotation and water maze test, brain edema and neuroinflammation were detected, and terminal-deoxynucleoitidyl transferase mediated dUTP nick end labeling (TUNEL), Fluoro-Jade C (FJC), and Nissl staining were performed.

RESULTS

Our data showed that WNK3 expression in brain tissue were upregulated after ICH induction. In addition, silencing of WNK3 reduced neuronal apoptosis, and inflammatory responses in rats that underwent ICH. Inhibition of WNK3 expression reduced the damaged blood-brain barrier (BBB), alleviated the impaired degree of cerebral edema, and improved disruptive neurobehavioral cognition caused by ICH. Moreover, overexpression of WNK3 had the opposite effects. Finally, WNK3/SPAK/NKCC1 signaling pathway may be involved in the above-mentioned processes.

CONCLUSIONS

In conclusion, our findings showed that WNK3 and WNK3/SPAK/NKCC1 signaling pathway play a vital biological function in ICH-induced SBI. Depletion of WNK3 attenuated brain injury after ICH both in vivo and in vitro. Thus, WNK3 and WNK3/SPAK/NKCC1 signaling pathway are potential targets for treating SBI after ICH.

Targeting CCL20 inhibits subarachnoid hemorrhage-related neuroinflammation in mice

Recent evidence suggests that CC chemokine ligand 20 (CCL20) is upregulated after subarachnoid hemorrhage (SAH). Here, we investigated the functions of CCL20 in SAH injury and its underlying mechanisms of action. We found that CCL20 is upregulated in an SAH mouse model and in cultured primary microglia and neurons. CCL20-neutralizing antibody alleviated SAH-induced neurological deficits, decreased brain water content and neuronal apoptosis, and repressed microglial activation. We observed increased levels of CCL20, CC chemokine receptor 6 (CCR6), interleukin 1 beta (IL-1β), and tumor necrosis factor alpha (TNF-α), as well as of microglial activation in microglia treated with oxyhemoglobin (OxyHb). CCL20 or CCR6 knockdown reversed the effects of OxyHb on microglia. Conditioned medium from OxyHb-treated microglia induced neuronal apoptosis, while the percentage of apoptotic neurons in the conditioned medium from microglia transfected with CCL20 siRNA or CCR6 siRNA was decreased. We observed no decrease in OxyHb-induced apoptosis in CCL20-knockdown neurons. Conditioned medium from OxyHb-treated neurons led to microglial activation and induced CCR6, IL-1β and TNF-α expression, while CCL20 knockdown in neurons or CCR6 knockdown in microglia reversed those effects. Our results thus suggest CCL20 may be targeted to elicit therapeutic benefits after SAH injury.

Changes in Expression of Receptor-Interacting Protein Kinase 1 in Secondary Neural Tissue Damage Following Spinal Cord Injury

Introduction:

Necroptosis is a form of programmed cell death that is different from apoptotic cell death. Receptor-interacting protein kinase 1 (RIPK1) plays a particularly important function in necroptosis execution. This study investigated changes in expression of RIPK1 in secondary neural tissue damage following spinal cord injury in mice. The time course of the RIPK1 expression was also compared with that of apoptotic cell death in the lesion site.

Methods and Materials:

Immunostaining for RIPK1 was performed at different time points after spinal cord injury. The protein expressions of RIPK1 were determined by western blot. The RIPK1 expressions in various neural cells were investigated using immunohistochemistry. To investigate the time course of apoptotic cell death, TUNEL-positive cells were counted at the different time points. To compare the incidence of necroptosis and apoptosis, the RIPK1-labeled sections were co-stained with TUNEL.

Results:

The RIPK1 expression was significantly upregulated in the injured spinal cord. The upregulation of RIPK1 expression was observed in neurons, astrocytes, and oligodendrocytes. The increase in RIPK1 expression started at 4 hours and peaked at 3 days after injury. Time course of the RIPK1 expression was similar to that of apoptosis detected by TUNEL. Interestingly, the increased expression of RIPK1 was rarely observed in the TUNEL-positive cells. Furthermore, the number of RIPK1-positive cells was significantly higher than that of TUNEL-positive cells.

Conclusions:

This study demonstrated that the expression of RIPK1 increased in various neural cells and peaked at 3 days following spinal cord injury. The temporal change of the RIPK1 expression was analogous to that of apoptosis at the lesion site. However, the increase in RIPK1 expression was barely seen in the apoptotic cells. These findings suggested that the RIPK1 might contribute to the pathological mechanism of the secondary neural tissue damage after spinal cord injury.

Assessment of necroptosis in the retina in a repeated primary ocular blast injury mouse model

Primary blast injury (caused by the initial rapid increase in pressure following an explosive blast) to the retina and optic nerve (ON) causes progressive visual loss and neurodegeneration. Military personnel are exposed to multiple low-overpressure blast waves, which may be in quick succession, such as during breacher training or in combat. We investigated the necroptotic cell death pathway in the retina in a mouse repeated primary ocular blast injury (rPBI) model using immunohistochemistry. We further evaluated whether intravitreal injections of a potent necroptosis inhibitor, Necrostatin-1s (Nec-1s), protects the retina and ON axons by retinal ganglion cells (RGC) counts, ON axonal counting and optical coherence tomography (OCT) analysis of vitreous haze. Receptor interacting protein kinase (RIPK) 3, increased in the inner plexiform layer 2 days post injury (dpi) and persisted until 14 dpi, whilst RIPK1 protein expression did not change after injury. The number of degenerating ON axons was increased at 28 dpi but there was no evidence of a reduction in the number of intact ON axons or RNA-binding protein with multiple splicing (RBPMS)⁺ RGC in the retina by 28 dpi in animals not receiving any intravitreal injections. But, when intravitreal injections (vehicle or Nec-1s) were given there was a significant reduction in RBPMS⁺ RGC numbers, suggesting that rPBI with intraocular injections is damaging to RGC. There were fewer RGC lost after Nec-1s than vehicle injection, but there was no effect of Nec-1s or vehicle treatment on the number of degenerating axons. OCT analysis demonstrated no effect of rPBI on vitreous haze, but intravitreal injection combined with rPBI increased vitreous haze (P = 0.004). Whilst necroptosis may be an active cell death signalling pathway after rPBI, its inhibition did not prevent cell death, and intravitreal injections in combination with rPBI increased vitreous inflammation and reduced RBPMS⁺ RGC numbers, implying intravitreal injection is not an ideal method for drug delivery after rPBI.

Miro1 Regulates Neuronal Mitochondrial Transport and Distribution to Alleviate Neuronal Damage in Secondary Brain Injury After Intracerebral Hemorrhage in Rats

Intracerebral hemorrhage (ICH) is a primary cause of death and disability in adults worldwide. Secondary brain injury (SBI) induced by ICH can lead to impaired mitochondrial function, which ultimately contributes to apoptosis and necrosis. Mitochondrial Rho GTPase 1 (Miro1) is a key regulator of mitochondrial movement and motor protein binding. Although Miro1 has been demonstrated to be implicated in various types of central nervous system damage, its potential effect on ICH-induced SBI has not been studied in detail. Hence, in the present new study, we explored the effect of Miro1 on SBI in vivo and in vitro. Self-body heart blood was injected into the right basal ganglia of the rat brain in vivo. Meanwhile, our in vitro model of ICH was based on the stimulation of oxygen hemoglobin (OxyHb) to neurons. Then, Miro1 was overexpressed both in the brains of rats after ICH in vivo and in OxyHb-treated cultured neurons in vitro. Miro1 overexpression in vivo reduced several pathological indexes such as brain edema, neurobehavioral impairment, and neuronal death. Immunofluorescent staining in vitro showed that overexpression of Miro1 ameliorated neuronal damage via facilitation of mitochondrial transport and distribution. JC-1 staining indicated that overexpression of Miro1 reduced the collapse of mitochondrial membrane potential and enhanced mitochondrial mass. Additionally, live-dead cellular staining and flow cytometry analysis revealed that Miro1 overexpression in cultured neurons reduced both necrotic and apoptotic rates. In contrast, inhibition of Miro1 expression yielded opposite effects to those of Miro1 overexpression. Above all, the upregulation of Miro1 significantly alleviated pathological symptoms on SBI in vivo and in vitro.