Neurovascular glial unit: A target of phytotherapy for cognitive impairments

Electroacupuncture promotes oligodendrocyte differentiation and myelin repair in a rat model of vascular dementia: Investigation of the mechanism from NF-κB-mediated inflammation

Myelin impairment is an important cause of cognitive impairment in vascular dementia (VD). Promoting myelin regeneration has become an important improvement strategy and oligodendrocytes are important targets. This study used a multiple microinfarctions (MMI)-induced VD rat model to reveal the mechanism of myelination of oligodendrocytes in the recovery of VD model, and to investigate the intervention mechanism of electroacupuncture (EA), an effective therapeutic for VD. Initially, our transcriptomic analysis identified 52 differentially expressed genes between the sham and MMI groups. These genes are primarily associated with axonal pathways, including the synaptic vesicle cycle, glutamatergic synapse, axon guidance, and sphingolipid metabolism. Compared with sham group, inflammation, impaired differentiation of oligodendrocyte precursor cells (OPCs) and myelin damage were remarkably observable in the hippocampus of MMI group, indicating the involvement of inflammation-regulated impairment of OPCs. Accordingly, pyrrolidinedithiocarbamate (PDTC), a NF-κB inhibitor could improve learning and memory impairment, reverse the hippocampal inflammation and impairment of OPCs differentiation, and decrease myelin damage in MMI rats. Importantly, EA could also improve learning and memory, attenuate the inflammatory response in the hippocampus and facilitate the differentiation of OPCs to aid in the repair of myelin damage in MMI rats. In conclusion, our data suggest that NF-κB activation is a prohibited factor for the myelin repair, while EA might reduce NF-κB activation and promote the differentiation of OPCs to repair the myelin damage in MMI rats.

Insight into cerebral microvessel endothelial regulation of cognitive impairment: A systematic review of the causes and consequences

Research on cognitive impairment (CI) has increasingly focused on the central nervous system, identifying numerous neuronal targets and circuits of relevance for CI pathogenesis and treatment. Brain microvascular endothelial cells (BMECs) form a barrier between the peripheral and central nervous systems, constituting the primary component of the blood-brain barrier (BBB) and playing a vital role in maintaining neural homeostasis. Stemming from the recognition of the close link between vascular dysfunction and CI, in recent years intense research has been devoted to characterize the pathological changes and molecular mechanisms underlying BMEC dysfunction both during normal aging and in disorders of cognition such as Alzheimer's disease and vascular dementia. In this review, keywords such as "dementia", "cognitive impairment", and "endothelium" were used to search PubMed and Web of Science. Based on the literature thus retrieved, we first review some common triggers of CI, i.e., amyloid beta and tau deposition, chronic cerebral hypoperfusion, hyperglycemia, viral infections, and neuroinflammation, and describe the specific mechanisms responsible for endothelial damage. Second, we review molecular aspects of endothelial damage leading to BBB disruption, neuronal injury, and myelin degeneration, which are crucial events underlying CI. Finally, we summarize the potential targets of endothelial damage in the development of cognitive dysfunction associated with Alzheimer's disease, vascular dementia, type 2 diabetes mellitus, and physiological aging. A thorough understanding of the induction mechanism and potential outcomes of microvascular endothelial damage is of great significance for the study of CI, to guide both diagnostic and therapeutic approaches for its prevention and treatment.

Exploring the mechanism of Pujin oral liquid in the treatment of preterm white matter injury using network pharmacology and molecular docking

We aimed to elucidate the pharmacological mechanisms of Pujin oral liquid in treating preterm white matter injury (PWMI). The Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform was used to identify Pujin oral liquid's active ingredients and predict their targets. The known targets related to treating PWMI were identified from the GeneCards, Online Mendelian Inheritance in Man, DisGeNet, PharmGKB, and CTD databases. A drug-disease intersecting protein-protein interaction network using a STRING database was built; gene ontology function and Kyoto Encyclopedia of Genes and Genomes signaling pathway enrichment analyses were performed on common target genes using the Metascape database. Molecular docking of the active ingredients and key targets was validated using the AutoDock Vina software. In total, 470 Pujin oral liquid targets and 13,290 disease targets were screened from multiple databases, and Venn analysis identified 407 common targets. Protein-protein interaction analysis showed that Pujin oral liquid may impact SRC, MAPK3, MAPK1, TP53, STAT3, AKT1, PIK3R1, JUN, RELA, CTNNB1, and ESR1. Moreover, gene ontology functional analysis revealed processes such as the response to inorganic substances, cellular response to organic cyclic compounds, response to xenobiotic stimuli, regulation of system processes, and protein phosphorylation. The main signaling pathways were neuroactive ligand-receptor interaction and the cGMP-PKG, JAK-STAT, and cAMP signaling pathways. Molecular docking showed that the active ingredients' small molecules bond strongly to target proteins. The therapeutic effect of Pujin oral liquid on PWMI is multifaceted, involving multiple targets and pathways. Its clinical application in treating preterm white matter injuries is promising.

Exploring the effects of moxibustion on cognitive function in rats with multiple cerebral infarctions from the perspective of glial vascular unit repairing

Objective

This study aimed to explore the effect of moxibustion at Governor Vessel (GV) acupoints, including Baihui (GV 20), Shenting (GV 24) and Dazhui (GV 14) for 14 days on glial vascular unit (GVU) in rats with multiple microinfarctions (MMI), and to explore its action mechanism.

Methods

The effect and mechanism of moxibustion on vascular dementia (VD) were studied in MMI rats by means of behavioral and molecular biology experiments.

Results

Rats receiving MMI showed impairment of memory function, reduction of cerebral blood flow, damage of blood-brain barrier (BBB) integrity and increased brain mass. MMI also increased neuronal degeneration in the hippocampus. Notably, levels of glial fibrillary acidic protein (GFAP) and complement component 3 significantly increased, but those of Connexin43 (CX43) and platelet derived growth factor receptor β (PDGFRβ) significantly decreased in the hippocampus of the rats receiving MMI. Moxibustion, as well as oxiracetam (ORC) treatment improved memory function and neuronal degeneration, ameliorated BBB integrity, increased cerebral blood flow and decreased brain mass. In addition, moxibustion as well as oxiracetam (ORC) treatment reduced the decrease of CX43 protein and increased PDGFRβ protein level in the hippocampus of MMI rats. Moreover, moxibustion treatment reversed MMI-induced increase of the GFAP/CX43 ratio in vascular structural units. Importantly, after PDGFRβ inhibition, VD rats treated with moxibustion had impaired learning and memory, decreased cerebral blood flow, and BBB disruption.

Conclusion

Moxibustion treatment at various GV acupoints improved cerebral blood flow and repaired BBB function in rats with MMI, likely through protecting GVU.

Molecular profiling of a rat model of vascular dementia: Evidences from proteomics, metabolomics and experimental validations

Decrease of cerebral blood flow is the primary cause of vascular dementia (VD), but its pathophysiological mechanisms are still not known. This study aims to profile the molecular changes of a rat model of VD induced by bilateral common carotid artery ligation. The Morris water maze and new object recognition tasks were used to test the cognitive function of rats. Hematoxylin and Eosin (HE) staining was used to detect pathological changes in the hippocampus. After confirming the model, proteomics was used to detect differentially expressed proteins in the hippocampus, and metabolomics was used to detect differential metabolites in rat serum. Thereafter, bioinformatics were used to integrate and analyze the potential molecular profile. The results showed that compared with the sham control group, the spatial and recognition memory of the rats were significantly reduced, and pathological changes were observed in the hippocampal CA1 region of the model group. Proteomic analysis suggested 206 differentially expressed proteins in the hippocampus of VD rats, with 117 proteins upregulated and 89 downregulated. Protein-protein interaction network analysis suggested that those differentially expressed proteins might play crucial roles in lipid metabolism, cell adhesion, intracellular transport, and signal transduction. Metabolomics analysis identified 103 differential metabolites, and comparison with the human metabolome database revealed 22 common metabolites, which predicted 265 potential targets. Afterwards, by intersecting the predicted results from metabolomics with the differentially expressed proteins from proteomics, we identified five potential targets, namely ACE, GABBR1, Rock1, Abcc1 and Mapk10. Furthermore, western blotting confirmed that compared with control group, hippocampal GABBR1 and Rock1 were enhanced in the model group. Together, this study showed the molecular profile of VD rats through a combination of proteomics, metabolomics, and experimental confirmation methods, offering crucial molecular targets for the diagnosis and treatment of VD.

Involvement of Astrocytes in the Formation, Maintenance, and Function of the Blood-Brain Barrier

The blood-brain barrier (BBB) is a fundamental structure that protects the composition of the brain by determining which ions, metabolites, and nutrients are allowed to enter the brain from the blood or to leave it towards the circulation. The BBB is structurally composed of a layer of brain capillary endothelial cells (BCECs) bound to each other through tight junctions (TJs). However, its development as well as maintenance and properties are controlled by the other brain cells that contact the BCECs: pericytes, glial cells, and even neurons themselves. Astrocytes seem, in particular, to have a very important role in determining and controlling most properties of the BBB. Here, we will focus on these latter cells, since the comprehension of their roles in brain physiology has been continuously expanding, even including the ability to participate in neurotransmission and in complex functions such as learning and memory. Accordingly, pathological conditions that alter astrocytic functions can alter the BBB's integrity, thus compromising many brain activities. In this review, we will also refer to different kinds of in vitro BBB models used to study the BBB's properties, evidencing its modifications under pathological conditions.