Human-induced pluripotent stem cell-derived neural stem cell exosomes improve blood-brain barrier function after intracerebral hemorrhage by activating astrocytes via PI3K/AKT/MCP-1 axis.

JOURNAL/nrgr/04.03/01300535-202502000-00029/figure1/v/2024-05-28T214302Z/r/image-tiff Cerebral edema caused by blood-brain barrier injury after intracerebral hemorrhage is an important factor leading to poor prognosis. Human-induced pluripotent stem cell-derived neural stem cell exosomes (hiPSC-NSC-Exos) have shown potential for brain injury repair in central nervous system diseases. In this study, we explored the impact of hiPSC-NSC-Exos on blood-brain barrier preservation and the underlying mechanism. Our results indicated that intranasal delivery of hiPSC-NSC-Exos mitigated neurological deficits, enhanced blood-brain barrier integrity, and reduced leukocyte infiltration in a mouse model of intracerebral hemorrhage. Additionally, hiPSC-NSC-Exos decreased immune cell infiltration, activated astrocytes, and decreased the secretion of inflammatory cytokines like monocyte chemoattractant protein-1, macrophage inflammatory protein-1α, and tumor necrosis factor-α post-intracerebral hemorrhage, thereby improving the inflammatory microenvironment. RNA sequencing indicated that hiPSC-NSC-Exo activated the PI3K/AKT signaling pathway in astrocytes and decreased monocyte chemoattractant protein-1 secretion, thereby improving blood-brain barrier integrity. Treatment with the PI3K/AKT inhibitor LY294002 or the monocyte chemoattractant protein-1 neutralizing agent C1142 abolished these effects. In summary, our findings suggest that hiPSC-NSC-Exos maintains blood-brain barrier integrity, in part by downregulating monocyte chemoattractant protein-1 secretion through activation of the PI3K/AKT signaling pathway in astrocytes.

Blood-brain barrier disruption following brain injury: Implications for clinical practice.

The blood-brain barrier (BBB) plays a critical role in regulating the exchange of substances between peripheral blood and the central nervous system and in maintaining the stability of the neurovascular unit in neurological diseases. To guide clinical treatment and basic research on BBB protection following brain injury, this manuscript reviews how BBB disruption develops and influences neural recovery after stroke and traumatic brain injury (TBI). By summarizing the pathological mechanisms of BBB damage, we underscore the critical role of promoting BBB repair in managing brain injury. We also emphasize the potential for personalized and precise therapeutic strategies and the need for continued research and innovation. From this, broadening insights into the mechanisms of BBB disruption and repair could pave the way for breakthroughs in the treatment of brain injury-related diseases.

Exosomes derived from microglia overexpressing miR-124-3p alleviate neuronal endoplasmic reticulum stress damage after repetitive mild traumatic brain injury.

JOURNAL/nrgr/04.03/01300535-202409000-00033/figure1/v/2024-01-16T170235Z/r/image-tiff We previously reported that miR-124-3p is markedly upregulated in microglia-derived exosomes following repetitive mild traumatic brain injury. However, its impact on neuronal endoplasmic reticulum stress following repetitive mild traumatic brain injury remains unclear. In this study, we first used an HT22 scratch injury model to mimic traumatic brain injury, then co-cultured the HT22 cells with BV2 microglia expressing high levels of miR-124-3p. We found that exosomes containing high levels of miR-124-3p attenuated apoptosis and endoplasmic reticulum stress. Furthermore, luciferase reporter assay analysis confirmed that miR-124-3p bound specifically to the endoplasmic reticulum stress-related protein IRE1α, while an IRE1α functional salvage experiment confirmed that miR-124-3p targeted IRE1α and reduced its expression, thereby inhibiting endoplasmic reticulum stress in injured neurons. Finally, we delivered microglia-derived exosomes containing miR-124-3p intranasally to a mouse model of repetitive mild traumatic brain injury and found that endoplasmic reticulum stress and apoptosis levels in hippocampal neurons were significantly reduced. These findings suggest that, after repetitive mild traumatic brain injury, miR-124-3 can be transferred from microglia-derived exosomes to injured neurons, where it exerts a neuroprotective effect by inhibiting endoplasmic reticulum stress. Therefore, microglia-derived exosomes containing miR-124-3p may represent a novel therapeutic strategy for repetitive mild traumatic brain injury.

IL-33/ST2 Axis: A Potential Therapeutic Target in Neurodegenerative Diseases.

Interleukin 33 (IL-33) belongs to the IL-1 family and is localized in the nucleus. IL-33 is primarily composed of three distinct domains, namely the N-terminal domain responsible for nuclear localization, the intermediate sense protease domain, and the C-terminal cytokine domain. Its specific receptor is the suppression of tumorigenicity 2 (ST2), which is detected in serum-stimulated fibroblasts and oncogenes. While most other cytokines are actively produced in cells, IL-33 is passively produced in response to tissue damage or cell necrosis, thereby suggesting its role as an alarm following cell infection, stress, or trauma. IL-33 plays a crucial role in congenital and acquired immunity, which assists in the response to environmental stress and maintains tissue homeostasis. IL-33/ST2 interaction further produces many pro-inflammatory cytokines. Moreover, IL-33 is crucial for central nervous system (CNS) homeostasis and the pathogenic mechanisms underlying CNS degenerative disorders. The present work summarizes the structure of IL-33, its fundamental activities, and its role in immunoregulation and neurodegenerative diseases. Therefore, this work proposes that IL-33 may play a role in the pathogenic mechanism of diseases and can be used in the development of treatment strategies.

Intranasal Delivery of Gene-Edited Microglial Exosomes Improves Neurological Outcomes after Intracerebral Hemorrhage by Regulating Neuroinflammation.

Neural inflammatory response is a crucial pathological change in intracerebral hemorrhage (ICH) which accelerates the formation of perihematomal edema and aggravates neural cell death. Although surgical and drug treatments for ICH have advanced rapidly in recent years, therapeutic strategies that target and control neuroinflammation are still limited. Exosomes are important carriers for information transfer among cells. They have also been regarded as a promising therapeutic tool in translational medicine, with low immunogenicity, high penetration through the blood-brain barrier, and ease of modification. In our previous research, we have found that exogenous administration of miRNA-124-overexpressed microglial exosomes (Exo-124) are effective in improving post-injury cognitive impairment. From this, we evaluated the potential therapeutic effects of miRNA-124-enriched microglial exosomes on the ICH mice in the present study. We found that the gene-edited exosomes could attenuate neuro-deficits and brain edema, improve blood-brain barrier integrity, and reduce neural cell death. Moreover, the protective effect of Exo-124 was abolished in mice depleted of Gr-1+ myeloid cells. It suggested that the exosomes exerted their functions by limiting the infiltration of leukocyte into the brain, thus controlling neuroinflammation following the onset of ICH. In conclusion, our findings provided a promising therapeutic strategy for improving neuroinflammation in ICH. It also opens a new avenue for intranasal delivery of exosome therapy using miRNA-edited microglial exosomes.

Potential blood biomarkers for chronic traumatic encephalopathy: The multi-omics landscape of an observational cohort.

Chronic traumatic encephalopathy (CTE) is a neurodegenerative disease associated with exposure to repetitive head impacts, which is susceptible in elderly people with declined mobility, athletes of full contact sports, military personnel and victims of domestic violence. It has been pathologically diagnosed in brain donors with a history of repetitive mild traumatic brain injury (rmTBI), but cannot be clinically diagnosed for a long time. By the continuous efforts by neuropathologists, neurologists and neuroscientists in recent 10 years, an expert consensus for the diagnostic framework of CTE was proposed in 2021 funded by the National Institute of Neurological Disorders and Stroke. The new consensus contributes to facilitating research in the field. However, it still needs to incorporate in vivo biomarkers to further refine and validate the clinical diagnostic criteria. From this, a single-center, observational cohort study has been being conducted by Tianjin Medical University General Hospital since 2021. As a pilot study of this clinical trial, the present research recruited 12 pairs of gender- and age-matched rmTBI patients with healthy subjects. Their blood samples were collected for exosome isolation, and multi-omics screening to explore potential diagnostic biomarkers in blood and its exosomes. The expression level of CHL1 protein, KIF2A mRNA, LIN7C mRNA, miR-297, and miR-1183 in serum and exosomes were found to be differentially expressed between groups. Besides, serum and exosomal CHL1, KIF2A, and miR-1183, as well as exosomal miR-297 were further verified as potential biomarkers for CTE by low-throughput assays. They are expected to contribute to establishing a novel set of CTE diagnostic signatures with classic neurodegenerative indicators in our future study, thereby updating the consensus diagnostic criteria for CTE by incorporating new evidence of the in vivo biomarkers.

Discovery of dehydroandrographolide derivatives with C19 hindered ether as potent anti-ZIKV agents with inhibitory activities to MTase of ZIKV NS5.

Infection by Zika virus (ZIKV), a mosquito-transmitted arbovirus and a member of Flavivirus, could make pediatric microcephaly and Guillain-Barré syndrome, which remains an ongoing global threat. The efficient antivirals to ZIKV infection are of great medical need. Andrographolide and its analogues were discovered to be active against flaviviral infection. In this study, we discovered some dehydroandrographolide derivatives of 3-oximido- or 3-alcohol-19-hindered ether to be potent anti-ZIKV agents with low cytotoxicities (CC50 > 200 µM). Time of addition assay suggests that compound 5a and its analogues act on inhibition of post-entry stage of ZIKV life cycle. It is discovered by experimental and molecular docking studies that active anti-ZIKV compounds of 3a, 5a, 5b and 5c possess inhibitory activities of ZIKV NS5 MTase (methyl transferase) enzymatic activity. Preliminary SAR reveals that C19-modification with bulky groups is necessary for anti-ZIKV infection and replication, anti-ZIKV activity of 5a comes from itself bearing hindered trityl ether but not from its instability, the backbone of dehydroandrographolide is more effective against ZIKV infection than that of andrographolide, and 3-oxime derivatives are more active against ZIKV infection than 3-alcohol derivatives. To our knowledge, 5a is the first reported MTase inhibitor of andrographolide derivatives. More importantly, discovery of active compound 5b with acid-stable 19-OCHPh2 against ZIKV infection is valued and gives us a clue to design and discover generally acid-stable anti-ZIKV agents.

Mesenchymal stromal cell treatment attenuates repetitive mild traumatic brain injury-induced persistent cognitive deficits via suppressing ferroptosis.

The incidence of repetitive mild traumatic brain injury (rmTBI), one of the main risk factors for predicting neurodegenerative disorders, is increasing; however, its underlying mechanism remains unclear. As suggested by several studies, ferroptosis is possibly related to TBI pathophysiology, but its effect on rmTBI is rarely studied. Mesenchymal stromal cells (MSCs), the most studied experimental cells in stem cell therapy, exert many beneficial effects on diseases of the central nervous system, yet evidence regarding the role of MSCs in ferroptosis and post-rmTBI neurodegeneration is unavailable. Our study showed that rmTBI resulted in time-dependent alterations in ferroptosis-related biomarker levels, such as abnormal iron metabolism, glutathione peroxidase (GPx) inactivation, decrease in GPx4 levels, and increase in lipid peroxidation. Furthermore, MSC treatment markedly decreased the aforementioned rmTBI-mediated alterations, neuronal damage, pathological protein deposition, and improved cognitive function compared with vehicle control. Similarly, liproxstatin-1, a ferroptosis inhibitor, showed similar effects. Collectively, based on the above observations, MSCs ameliorate cognitive impairment following rmTBI, partially via suppressing ferroptosis, which could be a therapeutic target for rmTBI.

A Novel Blood Inflammatory Indicator for Predicting Deterioration Risk of Mild Traumatic Brain Injury.

Mild traumatic brain injury (mTBI) has a relatively higher incidence in aging people due to walking problems. Cranial computed tomography and magnetic resonance imaging provide the standard diagnostic tool to identify intracranial complications in patients with mTBI. However, it is still necessary to further explore blood biomarkers for evaluating the deterioration risk at the early stage of mTBI to improve medical decision-making in the emergency department. The activation of the inflammatory response is one of the main pathological mechanisms leading to unfavorable outcomes of mTBI. As complete blood count (CBC) analysis is the most extensively used laboratory test in practice, we extracted clinical data of 994 patients with mTBI from two large clinical cohorts (MIMIC-IV and eICU-CRD) and selected inflammation-related indicators from CBC analysis to investigate their relationship with the deterioration after mTBI. The combinatorial indices neutrophil-to-lymphocyte ratio (NLR), red cell distribution width-to-platelet ratio (RPR), and NLR times RPR (NLTRP) were supposed to be potential risk predictors, and the data from the above cohorts were integratively analyzed using our previously reported method named MeDICS. We found that NLR, RPR, and NLTRP levels were higher among deteriorated patients than non-deteriorated patients with mTBI. Besides, high NLTRP was associated with increased deterioration risk, with the odds ratio increasing from NLTRP of 1-2 (2.69, 1.48-4.89) to > 2 (4.44, 1.51-13.08), using NLTRP of 0-1 as the reference. NLTRP had a moderately good prognostic performance with an area under the ROC curve of 0.7554 and a higher prediction value than both NLR and RPR, indicated by the integrated discrimination improvement index. The decision curve analysis also showed greater clinical benefits of NLTRP than NLR and RPR in a large range of threshold probabilities. Subgroup analysis further suggested that NLTRP is an independent risk factor for the deterioration after mTBI. In addition, in vivo experiments confirmed the association between NLTRP and neural/systemic inflammatory response after mTBI, which emphasized the importance of controlling inflammation in clinical treatment. Consequently, NLTRP is a promising biomarker for the deterioration risk of mTBI. It can be used in resource-limited settings, thus being proposed as a routinely available tool at all levels of the medical system.

Modafinil Reduces Neuronal Pyroptosis and Cognitive Decline After Sleep Deprivation.

Sleep deprivation (SD) induces systemic inflammation that promotes neuronal pyroptosis. The purpose of this study was to investigate the effect of an antioxidant modafinil on neuronal pyroptosis and cognitive decline following SD. Using a mouse model of SD, we found that modafinil improved learning and memory, reduced proinflammatory factor (IL-1ß, TNF-α, and IL-6) production, and increased the expression of anti-inflammatory factors (IL-10). Modafinil treatment attenuated inflammasome activity and reduced neuronal pyroptosis involving the NLRP3/NLRP1/NLRC4-caspase-1-IL-1ß pathway. In addition, modafinil induced an upregulation of brain-derived neurotrophic factor (BDNF) and synaptic activity. These results suggest that modafinil reduces neuronal pyroptosis and cognitive decline following SD. These effects should be further investigated in future studies to benefit patients with sleep disorders.

Red Cell Distribution Width to Platelet Count Ratio: A Promising Routinely Available Indicator of Mortality for Acute Traumatic Brain Injury.

Prognosis evaluation is crucial for the effective management of patients with acute traumatic brain injury (TBI). However, there is still a lack of routinely available blood indicators for mortality risk in clinical practice. To investigate whether blood red cell distribution width to platelet count ratio (RPR) correlates with hospital mortality of TBI, clinical data of 2220 patients with TBI were extracted from two large intensive care unit cohorts (MIMIC-III and eICU Database), and were integratively analyzed using our developed method named MeDICS. We found that higher RPR can be observed among non-survivors than survivors of TBI (p < 0.001). It had a moderately good prognostic performance for mortality with an area under receiver-operating characteristic curve (AUC) of 0.7367, which was greater than that of Glasgow Coma Scale (GCS; AUC = 0.6022). Besides, the nomogram consisting of RPR, GCS, and other risk factors was developed, where 10-fold cross-validation was performed to protect it against overfitting. A Harrell's C-index of 0.8523 was determined, suggesting an improved prognostic value based on RPR. The in vivo experiments further confirmed the association between RPR and neuro-outcome after TBI. It indicated that the continuous change in RPR post-injury is attributed to the development of inflammation, which emphasized the importance of controlling inflammatory response in clinical treatment. Taken together, RPR is a promising routinely available predictor of mortality for acute TBI. The nomogram generated from it can be used in resource-limited settings, thus be proposed as a prognosis evaluation aid for patients with TBI in all levels of medical system.

Relationship Between Amyloid-ß Deposition and Blood-Brain Barrier Dysfunction in Alzheimer's Disease.

Amyloid-ß (Aß) is the predominant pathologic protein in Alzheimer's disease (AD). The production and deposition of Aß are important factors affecting AD progression and prognosis. The deposition of neurotoxic Aß contributes to damage of the blood-brain barrier. However, the BBB is also crucial in maintaining the normal metabolism of Aß, and dysfunction of the BBB aggravates Aß deposition. This review characterizes Aß deposition and BBB damage in AD, summarizes their interactions, and details their respective mechanisms.

Dl-3-n-butylphthalide regulates cholinergic dysfunction in chronic cerebral hypoperfusion rats.

OBJECTIVES: To investigate whether dl-3-n-butylphthalide (NBP) affects cholinergic system function and ameliorates cognitive decline in a rat model of vascular dementia (VaD). METHODS: The VaD rat model was established by bilateral common carotid artery ligation (two-vessel occlusion, 2VO). Rats were divided into five groups: control, sham, 2VO, 2VO+NBP (80 mg/kg; intragastric), and 2VO+donepezil (1 mg/kg; intragastric). Treatments were administered once daily for 2 weeks from day 21 post-surgery. Spatial learning and memory were evaluated by Morris water maze performance. Hippocampal choline acetyltransferase (ChAT), acetylcholinesterase (AChE), vesicular acetylcholine transporter (VAChT), vascular endothelial growth factor (VEGF), and brain-derived neurotrophic factor (BDNF) expressions were detected using immunohistochemistry, immunofluorescence, and real-time polymerase chain reaction methods. RESULTS: The daily escape latency was significantly longer in 2VO rats than in the sham or control groups, while the time spent in the target quadrant was significantly shorter. The daily escape latency of the 2VO+NBP group was significantly shorter compared with the 2VO group. Following NBP treatment, ChAT, AChE, VAChT, and BDNF expressions were significantly upregulated in the hippocampus. CONCLUSIONS: Central cholinergic dysfunction may be involved in VaD pathogenesis. NBP treatment significantly improved spatial learning and memory in VaD rats, and may enhance cholinergic system function via BDNF-mediated neuroprotection.

Hydrogen improves cell viability partly through inhibition of autophagy and activation of PI3K/Akt/GSK3ß signal pathway in a microvascular endothelial cell model of traumatic brain injury.

Objective：Traumatic brain injury (TBI) is one of the most serious public health problems in the world. Hydrogen (H2), a flammable, colorless, and odorless gas, has been observed to have preventive and therapeutic effects on brain trauma and other neurological disorders, but its exact mechanism has not been fully clarified.Methods: To further study the mechanism underlying the role of hydrogen gas in alleviating BBB damage after TBI, we performed the scratch injury model on cultured brain microvascular endothelial cells (bEnd.3), which formed the microvascular endothelial barrier - an integral part of the highly specialized BBB.Results: In the case of TBI, hydrogen was able to improve the decline of cell viability induced by TBI. More importantly, inhibition of PI3 K/Akt/GSK3ß signal pathway or activation of autophagy reduced the protective effect of hydrogen on cell viability, indicating that such protective effect was regulated by PI3 K/Akt/GSK3ß signal pathway and was related to the inhibition of autophagy.Conclusion: So we concluded that hydrogen improved the cell viability in a microvascular endothelial cell model of TBI partly through inhibition of autophagy, and inhibitory effect of hydrogen on autophagy was exerted by activating PI3 K/Akt/GSK3ß signal pathway. These findings enriched our knowledge about the mechanism of hydrogen therapy against TBI.

Subdural haematomas drain into the extracranial lymphatic system through the meningeal lymphatic vessels.

Subdural haematomas (SDHs) are characterized by rapidly or gradually accumulated haematomas between the arachnoid and dura mater. The mechanism of haematoma clearance has not been clearly elucidated until now. The meningeal lymphatic vessel (mLV) drainage pathway is a novel system that takes part in the clearance of waste products in the central nervous system (CNS). This study aimed to explore the roles of the mLV drainage pathway in SDH clearance and its impacting factors. We injected FITC-500D, A488-fibrinogen and autologous blood into the subdural space of mice/rats and found that these substances drained into deep cervical lymph nodes (dCLNs). FITC-500D was also observed in the lymphatic vessels (LYVE+) of the meninges and the dCLNs in mice. The SDH clearance rate in SDH rats that received deep cervical lymph vessel (dCLV) ligation surgery was significantly lower than that in the control group, as evaluated by haemoglobin quantification and MRI scanning. The drainage rate of mLVs was significantly slower after the SDH model was established, and the expression of lymphangiogenesis-related proteins, including LYVE1, FOXC2 and VEGF-C, in meninges was downregulated. In summary, our findings proved that SDH was absorbed through the mLV drainage pathway and that haematomas could inhibit the function of mLVs.

ApoE mimetic improves pathology and memory in a model of Alzheimer's disease.

Alzheimer's disease (AD) is the most common form of dementia and is characterized pathologically by Aß plaques. Current treatments are purely symptomatic despite decades of intensive research interest. Notably, patients with the APOE4 allele are at increased risk for developing AD. One hypothesis regarding the mechanism by which the APOE4 allele might increase AD risk is loss of adaptive function, raising the possibility that the exogenous administration of apoE mimetics would have therapeutic effects. In this study, we utilized a previously characterized murine model of AD containing human APP, PS1 and APOE4TR, the APP/PS1/APOETR mouse. We treated male APP/PS1/APOETR mice with the apoE mimetic CN-105 or vehicle for 40d, beginning either at 14-18 or 25-28 weeks of age. After termination of treatment we tested animals in both Morris water maze and contextual fear conditioning, and examined soluble Aß by biochemistery and Aß deposition in cortex by unbiased stereology. We found that transient treatment with CN-105 for 40d beginning at 14-18 weeks reduced Aß pathology and rescued memory deficits in male APP/PS1/APOETR mice. Notably, delaying treatment onset to 25-28 weeks did not produce as robust an effect. These results suggest CN-105 treatment in a mouse model of AD results in a reduction in AD pathology and improved behavioral outcomes when administered early in the course of disease. As CN-105 has an excellent safety profile and is already in clinical trials, these findings raise the possibility that CN-105 represents a novel and translatable therapeutic strategy for AD.