Brain-Targeting Emodin Mitigates Ischemic Stroke via Inhibiting AQP4-Mediated Swelling and Neuroinflammation

Utilization of nanotechnology to surmount the blood-brain barrier in disorders of the central nervous system

Central nervous system (CNS) diseases are a major cause of disability and death worldwide. Due to the blood-brain barrier (BBB), drug delivery for CNS diseases is extremely challenging. Nano-delivery systems can overcome the limitations of BBB to deliver drugs to the CNS, improve the ability of drugs to target the brain and provide potential therapeutic methods for CNS diseases. At the same time, the choice of different drug delivery methods (bypassing BBB or crossing BBB) can further optimize the therapeutic effect of the nano-drug delivery system. This article reviews the different methods of nano-delivery systems to overcome the way BBB enters the brain. Different kinds of nanoparticles to overcome BBB were discussed in depth.

Electroacupuncture promotes neural function recovery by alleviating mitochondria damage in cerebral ischemia mice

AIMS

This study aimed to observe the effect of electroacupuncture (EA) at Zusanli point (ST36) on motor function of cerebral ischemia mice, and to observe the effect of EA on mitochondrial morphology of peri-infarct cortex neurons in cerebral ischemia mice.

METHODS

Middle cerebral artery occlusion (MCAO) was used to develop an ischemic stroke mice model. EA treatment was performed for three consecutive days for 15 min per day after MCAO modeling. We investigated the therapeutic effects of EA on MCAO mice by performing neurobehavioral assessment (modified Neurological Severity Score, Rotarod test, Open-field test and Gait analysis) and TTC staining. The morphology and function of neuronal mitochondria were evaluated by transmission electron microscopy, qRT-PCR, chemiluminescence, and western blot. Nissl staining, TUNEL staining and immunofluorescence staining were used to observe neuronal morphology and apoptosis. Furthermore, ELISA was employed to measure the expression levels of inflammatory factors in mouse serum.

RESULTS

EA alleviated motor dysfunction and infarct volume in mice with cerebral ischemia. It improved the neuronal mitochondria damage in MCAO mice, and decreased the protein and mRNA expression level of mitochondrial fission related proteins (FIS1 and Drp1). In addition, EA can reduce neuronal damage and apoptosis of nerve cells, and decrease the level of inflammatory factors (IL-1β, TNF-α, IL-6 and IL-8) in cerebral ischemia mice.

CONCLUSION

EA therapy can improve motor dysfunction and alleviate the damage of neuron mitochondria in cerebral ischemic mice.

Fenofibrate Reduces Ischemic Cerebral Edema via the Suppression of Aquaporin-4

The study aimed to investigate the neuroprotective effects of fenofibrate (FENO), a triglyceride-lowering drug, in rats with cerebral ischemia. An ischemic cerebral edema model was established in rats, and an oxygen-glucose deprivation/reoxygenation (OGD/R) model was created in astrocytes. Neurological deficits were quantified using a standardized deficit score. Protein expression levels were assessed through immunohistochemical staining, western blot analysis, and enzyme-linked immunosorbent assays (ELISA). Gene expression was determined using real-time polymerase chain reaction (RT-PCR), while luciferase activity was measured using a commercially available kit. We found that FENO significantly reduced infarct volume and neurological deficits in rats subjected to middle cerebral artery occlusion (MCAO). Additionally, FENO inhibited increased brain water content and upregulated the expression of aquaporin-4 (AQP4), a protein associated with cerebral edema, in the ischemic hemisphere. Furthermore, FENO suppressed the inflammatory response in cortical tissue by reducing the expression of cytokines such as interleukin-6 (IL-6), monocyte chemoattractant protein-1 (MCP-1), and tumor necrosis factor-alpha (TNF-α). It also increased the expression of myeloperoxidase (MPO) and promoted activation of astrocytes by increasing glial fibrillary acidic protein (GFAP). In vitro experiments further demonstrated that FENO reduced the expression of AQP4 against OGD/R in primary rat astrocytes. FENO also inhibited the activation of p38 by reducing its phosphorylation. Correspondingly, FENO suppressed the activation of activator protein 1 (AP-1) by reducing the levels of c-Jun and c-Fos, as well as the luciferase activity of AP-1. These effects were enhanced by the p38 specific inhibitor SB203580. Notably, the presence of the AP-1 specific inhibitor T5224 further promoted the effects of FENO in suppressing the expression of AQP4, implicating that the inhibitory effects of FENO on AQP4 expression are mediated by the p38/AP-1 signaling pathway. These findings suggest that FENO may have potential therapeutic benefits in stroke by targeting the p38/AP-1 signaling pathway and reducing AQP4 expression, thereby alleviating cerebral edema and inflammation.

Recent advances in self-targeting natural product-based nanomedicines

Natural products, recognized for their potential in disease prevention and treatment, have been integrated with advanced nano-delivery systems to create natural product-based nanomedicines, offering innovative approaches for various diseases. Natural products derived from traditional Chinese medicine have their own targeting effect and remarkable therapeutic effect on many diseases, but there are some shortcomings such as poor physical and chemical properties. The construction of nanomedicines using the active ingredients of natural products has become a key step in the modernization research process, which could be used to make up for the defects of natural products such as low solubility, large dosage, poor bioavailability and poor targeting. Nanotechnology enhances the safety, selectivity, and efficacy of natural products, positioning natural product-based nanomedicines as promising candidates in medicine. This review outlines the current status of development, the application in different diseases, and safety evaluation of natural product-based nanomedicines, providing essential insights for further exploration of the synergy between natural products and nano-delivery systems in disease treatment.

Trillium tschonoskii rhizome saponin improves spatial learning and memory by enhancing neurovascular restorative in ischemic rats

BACKGROUND

Trillium tschonoskii rhizome saponins (TSTT) has been significantly effective in treating traumatic injury, neurasthenia, cancer and inflammatory diseases as a folk medicine. However, the mechanism regarding to TSTT induced the neurovascular restorative after ischemia is without fully elucidated.

PURPOSE

This research was constructed to study the value of TSTT in promoting endogenous repair of neurovascular and augmenting the ability of spatial study and memory retention in ischaemic rats.

STUDY DESIGN

The improvement of TSTT on cerebral infraction and perfusion was observed by magnetic resonance imaging (MRI) experiments and the molecular mechanisms were further explored.

METHODS

First, rats were ligated the middle cerebral artery to construct a permanent ischaemia model, subsequently intragastric injection administrated with TSTT (120, 60, 30 mg kg-1) at 6 h after operation, then once a day during next 30 days. Morris water maze was applied to observe the neurobehavioral changes. Multimodal MRI sequences were performed to monitoring brain injuries as well as cerebral blood flow. Histopathological staining was employed to evaluate the morphological changes of neurons. Transmission electron microscopy (TEM) was employed to detect the neurons, vascular structure, and synapse. Immunofluorescent staining was utilized to evaluate the endogenous repair progress. The axonal growth-inhibitors and axonal guidance cues were analyzed using western blotting.

RESULTS

Contrast to the model group, TSTT declined the infarction and elevated the parenchymal volume. Notably, treated with TSTT significantly decreased the ADC (ipsilateral/contralateral). In histopathologic examination, TSTT prominently boosted amounts of cortical and striatal nerve cells and protected ultrastructure of neurovascular unit. According with results of nuclear magnetic imaging, TSTT enhanced endogenous repair progress. Especially, TSTT treatments obviously inhibited protein levels of NogoA/NgR/RhoA/ROCK2, accompanied by increased expression of Netrin/DCC and Slit2/Robo1.

CONCLUSION

To sum up, our data illustrated that TSTT promoted cerebral reestablishment. The above result was in line with improving cerebral blood flow, elevated integrity of neurovascular structure, accelerating endogenous restoration and impairing the axonal growth inhibitors NogoA/NgR/RhoA/ROCK2 signaling, thereby improving poststroke learning and memory.

Comprehensive spatial distribution profiling of bioactive emodin in mouse organs using mass spectrometry imaging

Emodin is an important anthraquinone compound with good anti-inflammatory activity in Chinese traditional medicine rhubarb. Detailed spatial distribution information in bio-tissues plays an important role in revealing the pharmacodynamics, toxicology and chemical mechanism of emodin. Herein, the matrix-assisted laser desorption/ionization time-of-flight mass spectrometry imaging (MALDI-TOF-MSI) analytical method was established to obtain information on the spatial and temporal changes of emodin in multiple mouse tissue sections (heart, liver, spleen, lung, kidney, and brain) after intraperitoneal injection of emodin in mice. The measurements were accomplished in the negative ion mode in the range of m/z 250-285 Da with a spatial resolution on 40 µm. It was found that emodin was predominantly distributed in the arteriolar vascular region of the heart, the capsule region of the spleen, and the cortex of the kidney. Moreover, the MALDI-TOF-MSI result implied that emodin might be distributed in the brain. These more detailed spatial distribution information provides the significant reference for investigating the action mechanism of emodin, which cannot be obtained from conventional LC-MS analysis. The distribution trend of emodin in the results of MALDI-TOF-MSI analysis agreed with the ultra-performance liquid chromatography/tandem mass spectrometry (UPLC-MS/MS) results well, demonstrating the complementarity and reliability of the established MALDI-TOF-MSI method. Our work provided a label-free molecular imaging method to investigate the precise spatial distribution of emodin in various organs, which prove great potential in studying the effective substances and mechanism of rhubarb.

Innovations in Breaking Barriers: Liposomes as Near-Perfect Drug Carriers in Ischemic Stroke Therapy

Liposomes, noted for their tunable particle size, surface customization, and varied drug delivery capacities, are increasingly acknowledged in therapeutic applications. These vesicles exhibit surface flexibility, enabling the incorporation of targeting moieties or peptides to achieve specific targeting and avoid lysosomal entrapment. Internally, their adaptable architecture permits the inclusion of a broad spectrum of drugs, contingent on their solubility characteristics. This study thoroughly reviews liposome fabrication, surface modifications, and drug release mechanisms post-systemic administration, with a particular emphasis on drugs crossing the blood-brain barrier (BBB) to address lesions. Additionally, the review delves into recent developments in the use of liposomes in ischemic stroke models, offering a comparative evaluation with other nanocarriers like exosomes and nano-micelles, thereby facilitating their clinical advancement.

The application strategy of liposomes in organ targeting therapy

Liposomes-microscopic phospholipid bubbles with bilayered membrane structure-have been a focal point in drug delivery research for the past 30 years. Current liposomes possess a blend of biocompatibility, drug loading efficiency, prolonged circulation and targeted delivery. Tailored liposomes, varying in size, charge, lipid composition, and ratio, have been developed to address diseases in specific organs, thereby enhancing drug circulation, accumulation at lesion sites, intracellular delivery, and treatment efficacy for various organ-specific diseases. For further successful development of this field, this review summarized liposomal strategies for targeting different organs in series of major human diseases, including widely studied cardiovascular diseases, liver and spleen immune diseases, chronic or acute kidney injury, neurodegenerative diseases, and organ-specific tumors. It highlights recent advances of liposome-mediated therapeutic agent delivery for disease intervention and organ rehabilitation, offering practical guidelines for designing organ-targeted liposomes. This article is categorized under: Therapeutic Approaches and Drug Discovery > Emerging Technologies Biology-Inspired Nanomaterials > Lipid-Based Structures.

Mitochondrial stress: a key role of neuroinflammation in stroke

Stroke is a clinical syndrome characterized by an acute, focal neurological deficit, primarily caused by the occlusion or rupture of cerebral blood vessels. In stroke, neuroinflammation emerges as a pivotal event contributing to neuronal cell death. The occurrence and progression of neuroinflammation entail intricate processes, prominently featuring mitochondrial dysfunction and adaptive responses. Mitochondria, a double membrane-bound organelle are recognized as the "energy workshop" of the body. Brain is particularly vulnerable to mitochondrial disturbances due to its high energy demands from mitochondria-related energy production. The interplay between mitochondria and neuroinflammation plays a significant role in the pathogenesis of stroke. The biological and pathological consequences resulting from mitochondrial stress have substantial implications for cerebral function. Mitochondrial stress serves as an adaptive mechanism aimed at mitigating the stress induced by the import of misfolded proteins, which occurs in response to stroke. This adaptive response involves a reduction in misfolded protein accumulation and overall protein synthesis. The influence of mitochondrial stress on the pathological state of stroke is underscored by its capacity to interact with neuroinflammation. The impact of mitochondrial stress on neuroinflammation varies according to its severity. Moderate mitochondrial stress can bolster cellular adaptive defenses, enabling cells to better withstand detrimental stressors. In contrast, sustained and excessive mitochondrial stress detrimentally affects cellular and tissue integrity. The relationship between neuroinflammation and mitochondrial stress depends on the degree of mitochondrial stress present. Understanding its role in stroke pathogenesis is instrumental in excavating the novel treatment of stroke. This review aims to provide the evaluation of the cross-talk between mitochondrial stress and neuroinflammation within the context of stroke. We aim to reveal how mitochondrial stress affects neuroinflammation environment in stroke.

Emerging diagnostic markers and therapeutic targets in post-stroke hemorrhagic transformation and brain edema

Stroke is a devastating condition that can lead to significant morbidity and mortality. The aftermath of a stroke, particularly hemorrhagic transformation (HT) and brain edema, can significantly impact the prognosis of patients. Early detection and effective management of these complications are crucial for improving outcomes in stroke patients. This review highlights the emerging diagnostic markers and therapeutic targets including claudin, occludin, zonula occluden, s100β, albumin, MMP-9, MMP-2, MMP-12, IL-1β, TNF-α, IL-6, IFN-γ, TGF-β, IL-10, IL-4, IL-13, MCP-1/CCL2, CXCL2, CXCL8, CXCL12, CCL5, CX3CL1, ICAM-1, VCAM-1, P-selectin, E-selectin, PECAM-1/CD31, JAMs, HMGB1, vWF, VEGF, ROS, NAC, and AQP4. The clinical significance and implications of these biomarkers were also discussed.