Lijuan Song

Objective: To investigate the potential mechanisms of Piper longum L. in the treatment of cerebral ischemic stroke (CIS) and conduct experimental verification. Methods: Network pharmacology was used to identify intersecting targets of Piper longum L. and CIS. A drug-active component-target-disease network and the target protein-protein interaction (PPI) network were subsequently constructed, to screen major components and key targets. The intersecting targets were subjected to comprehensive Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses. Molecular docking and molecular dynamics (MD) simulations were performed to assess the binding energy and stability between the main active components and core targets. Surface plasmon resonance (SPR) was also employed to validate these binding interactions, providing further evidence for the underlying molecular mechanisms. Results: In total, 13 active components were identified in Piper longum L., and 60 intersectional targets were acquired. Among the main active components were piperine, 1,2,5,6-tetrahydrotanshinone, sesamin, N-(2,5-dimethoxyphenyl)-4-methoxybenzamide, and pipernonaline. The key targets predominantly consisted of tumor necrosis factor (TNF), interleukin-6 (IL-6), prostaglandin-endoperoxide synthase 2 (PTGS2), cAMP response element-binding protein (CREB1), and interleukin-1β (IL-1β). These identified targets were enriched in 77 GO terms and involved in multiple signaling pathways, including the TNF and cAMP (cyclic adenosine monophosphate) pathways. The main active components exhibit low binding energies with the key targets. MD simulations further demonstrated the structural stability of the complex formed between the main component, sesamin, and the associated CREB1 target, as well as the significance of key residues ILE240 (isoleucine240), ARG241 (arginine241), and PRO244 (proline244) in the binding interaction. Finally, the SPR method provided experimental evidence of the direct binding between sesamin and CREB1. Conclusions: Piper longum L. may exert pharmacological effects on CIS by acting on targets such as CREB1, PTGS2, and TNF, and by modulating signaling pathways including cAMP and inflammation.

Lipocalin-2 (LCN2), an acute phase protein mainly expressed in astrocytes (Ast), is closely related to the production of inflammatory cytokines following ischemic stroke. During the pathophysiological process of ischemic stroke, the Janus kinase 2/signal transducer and activator of transcription 3 (JAK2/STAT3) signaling pathway is activated. Despite evidence suggesting some link between the two, the relationship between the JAK2/STAT3 signaling pathway and the LCN2 expression in Ast following brain ischemia is incompletely understood. Hydroxysafflower yellow A (HSYA), an active ingredient found in Carthamus tinctorius L flowers, has been demonstrated to effectively mitigate cerebral ischemia via its anti-inflammatory effect. However, whether HSYA mitigates the neuroinflammatory damage after ischemic stroke by disrupting the interaction between the JAK2/STAT3 signaling pathway and LCN2 in Ast is unknown. Focusing on these two scientific questions, we established an in vivo middle cerebral artery occlusion/reperfusion (MCAO/R) rat model and in vitro primary astrocyte oxygen glucose deprivation/reperfusion (OGD/R) model. In vivo results showed that HSYA treatment alleviated nerve damage and inhibited the expression of LCN2 and inflammatory factors in Ast. In vitro results showed after OGD/R the expression of LCN2 and inflammatory cytokines increased and the JAK2/STAT3 was activated in Ast. Meanwhile, after OGD/R the JAK2/STAT3 activation in Ast increased LCN2 expression, and the inhibition of LCN2 expression by HSYA decreased the JAK2/STAT3 activation in Ast. These findings suggest that there is an interaction between the LCN2 and JAK2/STAT3 in Ast after ischemic stroke, which can enhance the inflammatory factors and exacerbate neuroinflammatory injury. Therefore, we conclude that HSYA may inhibit the LCN2/STAT3 loop in Ast, thereby mitigating neuroinflammation after cerebral ischemia.

Alzheimer’s disease (AD) is characterized by cognitive decline stemming from the accumulation of beta-amyloid (Aβ) plaques and the propagation of tau pathology through synapses. Exosomes, crucial mediators in neuronal development, maintenance, and intercellular communication, have gained attention in AD research. Yet, the molecular mechanisms involving exosomal miRNAs in AD remain elusive. In this study, we treated APPswe/PSEN1dE9 transgenic (APP/PS1) mice, a model for AD, with either vehicle (ADNS) or fasudil (ADF), while C57BL/6 (control) mice received vehicle (WT). Cognitive function was evaluated using the Y-maze test, and AD pathology was confirmed through immunostaining and western blot analysis of Aβ plaques and phosphorylated tau. Exosomal RNAs were extracted, sequenced, and analyzed from each mouse group. Our findings revealed that fasudil treatment improved cognitive function in AD mice, as evidenced by increased spontaneous alternation in the Y-maze test and reduced Aβ plaque load and phosphorylated tau protein expression in the hippocampus. Analysis of exosomal miRNAs identified three miRNAs (mmu-let-7i-5p, mmu-miR-19a-3p, mmu-miR-451a) common to both ADNS vs ADF and WT vs ADNS groups. Utilizing miRTarBase software, we predicted and analyzed target genes associated with these miRNAs. Gene ontology (GO) annotation and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis of miRNA target genes indicated that mmu-miR-19a-3p and mmu-miR-451a are implicated in signal transduction, immune response, cellular communication, and nervous system pathways. Specifically, mmu-miR-19a-3p targeted genes involved in the sphingolipid signaling pathway, such as Pten and Tnf, while mmu-miR-451a targeted Nsmaf, Gnai3, and Akt3. Moreover, mmu-miR-451a targeted Myc in signaling pathways regulating the pluripotency of stem cells. In conclusion, fasudil treatment enhanced cognitive function by modulating exosomal MicroRNAs, particularly mmu-miR-451a and mmu-miR-19a-3p. These miRNAs hold promise as potential biomarkers and therapeutic targets for novel AD treatments. Graphical Abstract

Ischemic stroke (IS) is a leading cause of death and disability worldwide. Tissue plasminogen activator (tPA) administration and mechanical thrombectomy are the main treatments but have a narrow time window. Mesenchymal stem cells (MSCs), which are easily scalable in vitro and lack ethical concerns, possess the potential to differentiate into various types of cells and secrete a great number of growth factors for neuroprotection and regeneration. Moreover, MSCs have low immunogenicity and tumorigenic properties, showing safety and preliminary efficacy both in preclinical studies and clinical trials of IS. However, it is unlikely that MSC treatment alone will be sufficient to maximize recovery due to the low survival rate of transplanted cells and various mechanisms of ischemic brain damage in the different stages of IS. Preconditioning was used to facilitate the homing, survival, and secretion ability of the grafted MSCs in the ischemic region, while combination therapies are alternatives that can maximize the treatment effects, focusing on multiple therapeutic targets to promote stroke recovery. In this case, the combination therapy can yield a synergistic effect. In this review, we summarize the type of MSCs, preconditioning methods, and combined strategies as well as their therapeutic mechanism in the treatment of IS to accelerate the transformation from basic research to clinical application.

The treatment of immunomodulation in multiple sclerosis (MS) can alleviate the severity and relapses. However, it cannot improve the neurological disability of patients due to a lack of myelin protection and regeneration. Therefore, remyelinating therapies may be one of the feasible strategies that can prevent axonal degeneration and restore neurological disability. Natural product icariin (ICA) is a flavonol compound extracted from epimedium flavonoids, which has neuroprotective effects in several models of neurological diseases. Here, we attempt to explore whether ICA has the potential to treat demyelination and its possible mechanisms of action using lipopolysaccharide-treated BV2 microglia, primary microglia, bone marrow-derived macrophages, and cuprizone-induced demyelination model. The indicators of oxidative stress and inflammatory response were evaluated using commercial kits. The results showed that ICA significantly reduced the levels of oxidative intermediates nitric oxide, hydrogen peroxide, malondialdehyde, and inflammatory cytokines TNF-α, IL-1β, and increased the levels of antioxidants superoxide dismutase, catalase, glutathione peroxidase, and anti-inflammatory cytokines IL-10 and TGF-β in vitro cell experiments. In vivo demyelination model, ICA significantly alleviated the behavioral abnormalities and enhanced the integrated optical density/mm² of Black Gold II and myelin basic protein myelin staining, accompanied by the inhibition of oxidative stress/inflammatory response. Immunohistochemical staining showed that ICA significantly induced the expression of nuclear factor erythroid derived 2/heme oxygenase-1 (Nrf2/HO-1) and inhibited the expression of toll-like receptor 4/ nuclear factor kappa B (TLR4/NF-κB), which are two key signaling pathways in antioxidant and anti-inflammatory processes. Our results strongly suggest that ICA may be used as a potential agent to treat demyelination via regulating Nrf2/HO-1-mediated antioxidative stress and TLR4/NF-κB-mediated inflammatory responses.

Background Information: Persistent myelin debris can inhibit axonal regeneration, thereby hindering remyelination. Effective removal of myelin debris is essential to eliminate the interference of myelin debris in oligodendrocyte progenitor cell (OPC) activation, recruitment to demyelinating sites and/or differentiation into mature oligodendrocytes (OLs). In addition to microglia, it has been reported that astrocytic phagocytosis of myelin debris is a feature of early demyelination.Results: In the present study, astrocytes effectively phagocytized myelin debris in vitro and in vivo. On the 5th day after injecting myelin debris into the brain, astrocytes were enriched in the area injected with myelin debris compared with microglia, and their ability to engulf myelin debris was stronger than that of microglia. When exposed to myelin debris, astrocytes phagocytizing myelin debris triggered self‐apoptosis, accompanied by the activation of NF‐κB, down‐regulation of Nrf2, and the increase of ciliary neurotrophic factor (CNTF) and basic fibroblast growth factor (bFGF). However, the activation of astrocytic NF‐κB did not influence the inflammatory cytokines IL‐1β, IL‐6, and TNF‐α, and the anti‐inflammatory factor IL‐10. The proliferation of astrocytes and mobilization of OPCs in the subventricular zone were elevated on the 5th day after intracerebral injection of myelin debris.Conclusions: The results suggested that myelin phagocytosis of astrocytes should help improve the microenvironment and promote myelin regeneration by increasing CNTF and bFGF within the central nervous system.Significance: However, the molecular interaction of astrocytes acting as phagocytes remains to be further explored. Therefore, an improvement of astrocytes to phagocytize myelin debris may be a promising treatment measure to prevent demyelination and promote remyelination in MS and other diseases with prominent myelin injury.

Astragaloside IV (AST IV), a major saponin component and active ingredient isolated from Astragalus membranaceus, has been well known to exhibit neuroprotective effects on diverse models of neurological diseases. Accumulating evidence suggests that dynamic balance of microglia/macrophages and...

In the process of ischemic stroke (IS), cellular macroautophagy/autophagy and apoptosis play a vital role in neuroprotection against it. Therefore, regulating their balance is a potential therapeutic strategy. It has been proved that hydroxysafflor yellow A (HSYA) has anti-inflammatory and antioxidant effects, which can both protect neurons. By exploring bioinformatics combined with network pharmacology, we found that HIF1A and CASP3, key factors regulating autophagy and apoptosis, may be important targets of HSYA for neuroprotection in an oxygen glucose deprivation and reperfusion (OGD/R) model. In this study, we explored a possible new mechanism of HSYA neuroprotection in the OGD/R model. The results showed that OGD/R increased the expression of HIF1A and CASP3 in SH-SY5Y cells and induced autophagy and apoptosis, while HSYA intervention further promoted the expression of HIF1A and inhibited the level of CASP3, accompanied by an increase in autophagy and a decrease in apoptosis in SH-SY5Y cells. The inhibition of HIF1A diminished the activation of autophagy induced with HSYA, while the inhibition of autophagy increased cell apoptosis and blocked the neuroprotective effect of HSYA, suggesting that the neuroprotective effect of HSYA should be mediated by activating the HIF1A/BNIP3 signaling pathway to induce autophagy. These results demonstrate that HSYA may be a promising agent for treating IS.

Background: The etiology of Parkinson’s disease (PD), a chronic and progressive neurodegenerative disease, is multifactorial but not fully unknown. Until now, no drug has been proven to have neuroprotective or neuroregenerative effects in patients with PD. Objectives: To observe the therapeutic potential of Bilobalide (BB), a constituent of ginkgo biloba, in MPTP-induced PD model, and explore its possible mechanisms of action. Material and Methods: Mice were randomly divided into three groups: healthy group, MPTP group and MPTP + BB group. PD-related phenotypes were induced by intraperitoneal injection of MPTP into male C57BL/6 mice, and BB (40 mg/kg/day) was intraperitoneally given for 7 consecutive days at the end of modeling. The injection of saline was set up as the control in a similar manner. Results: BB induced M2 polarization of microglia, accompanied by inhibition of neuroinflammation in the brain. Simultaneously, BB promoted the expression of BDNF in astrocytes and neurons, and expression of GDNF in neurons. Most interestingly, BB enhanced the formation of GFAP⁺ astrocytes expressing nestin, Brn2 and Ki67, as well as the transformation of GFAP⁺ astrocytes expressing tyrosine hydroxylase around subventricular zone, providing experimental evidence that BB could promote the conversion of astrocytes into TH⁺ dopamine neurons in vivo and in vitro. Conclusions: These results suggest the natural product BB may utilize multiple pathways to modify degenerative process of TH⁺ neurons, revealing an exciting opportunity for novel neuroprotective therapeutics. However, its multi-target and important mechanisms need to be further explored. Graphical Abstract

In recent years, neurovascular unit (NVU) which is composed of neurons, astrocytes (Ast), microglia (MG), vascular cells and extracellular matrix (ECM), has become an attractive field in ischemic stroke. As the important component of NVU, Ast closely interacts with other constituents, which has been playing double-edged sword roles, beneficial or detrimental after ischemic stroke. Based on the pathophysiological changes, we evaluated some strategies for targeting Ast in treating ischemic stroke. The present review is focused on the roles of Ast in NVU and its complex signaling molecular network after ischemic stroke, which may be a prospective approach to the treatment of ischemic diseases in central nervous system.