l-Borneol Exerted the Neuroprotective Effect by Promoting Angiogenesis Coupled With Neurogenesis via Ang1-VEGF-BDNF Pathway

Natural herbal extract roles and mechanisms in treating cerebral ischemia: A systematic review

Background

Stroke has been the focus of medical research due to its serious consequences and sequelae. Among the tens of millions of new stroke patients every year, cerebral ischemia patients account for the vast majority. While cerebral ischemia drug research and development is still ongoing, most drugs are terminated at preclinical stages due to their unacceptable toxic side effects. In recent years, natural herbs have received considerable attention in the pharmaceutical research and development field due to their low toxicity levels. Numerous studies have shown that natural herbs exert actions that cannot be ignored when treating cerebral ischemia.

Methods

We reviewed and summarized the therapeutic effects and mechanisms of different natural herbal extracts on cerebral ischemia to promote their application in this field. We used keywords such as "natural herbal extract," "herbal medicine," "Chinese herbal medicine" and "cerebral ischemia" to comprehensively search PubMed, ScienceDirect, ScienceNet, CNKI, and Wanfang databases, after which we conducted a detailed screening and review strategy.

Results

We included 120 high-quality studies up to 10 January 2024. Natural herbal extracts had significant roles in cerebral ischemia treatments via several molecular mechanisms, such as improving regional blood flow disorders, protecting the blood-brain barrier, and inhibiting neuronal apoptosis, oxidative stress and inflammatory responses.

Conclusion

Natural herbal extracts are represented by low toxicity and high curative effects, and will become indispensable therapeutic options in the cerebral ischemia treatment field.

Vasculature cells control neuroglial co-localization and synaptic connection in a central nervous system tissue mimic system

Despite the development of neural tissue differentiation methods using a wide variety of stem cells and compartments, there is no standardized strategy for establishing synapses. As the neuronal network is developed in parallel with blood vessel angiogenesis in the central nervous system (CNS) from the embryonic period, we examined neuron-astrocyte-vasculature interactions to understand the effect of the vasculature on the development and stabilization of neurological morphogenesis. We generated a cellular co-culture module targeting the CNS that was embedded in a collagen-based extracellular matrix (ECM) gel. Our neuron-astrocyte-vascular complex module identified the neurological co-localization effect by endothelial cells, as well as the pericyte-induced improvement of synaptic connections. Furthermore, it was suggested that the PDGF, BDNF, IGF, and WNT/BMP pathways were upregulated in synaptic connections enhanced conditions, which are composed of neurexin. These results suggest that the integrity of the vasculature cells in the CNS is important for the establishment of neuronal networks and for synapse connection.

Neuroprotective effect of Astragali Radix on cerebral infarction based on proteomics

Objective: Astragali Radix (AR, Huangqi in Chinese) has a neuroprotective effect on cerebral infarction (CI). In order to explore the biological basis and therapeutic mechanism of AR in CI, a double-blind randomized controlled trial was established in this study, and proteomics analysis was carried out on serum samples of patients. Methods: The patients were divided into the AR group (n = 35) and the control group (n = 30). The curative effect was evaluated by the traditional Chinese medicine (TCM) syndrome score and clinical indicators, and the serum of the two groups was analyzed by proteomics. Based on bioinformatics analysis methods, the changes in differential proteins between two groups of samples were explored, and the key proteins were validated through enzyme-linked immunosorbent assay (ELISA). Results: The results of this study showed that the scores of deficiency of vital energy (DVE), blood stasis (BS), and NIH Stroke Scale (NIHSS) decreased significantly (p < 0.05), while the scores of the Barthel Index (BI) increased, indicating that AR could significantly improve the symptoms of CI patients. In addition, we found that compared with the control group, AR upregulated 43 proteins and downregulated 20 proteins, especially focusing on anti-atherosclerosis and neuroprotective effects. Moreover, ELISA indicated the levels of IL-6, TNF-α, VCAM-1, MCP-1, and ICAM-1 were significantly decreased in the serum of the AR group (p < 0.05, p < 0.01). Conclusion: This study found that AR can significantly recover the clinical symptoms of CI. Serum proteomics research results show that AR may act on IL-6, TNF-α, VCAM-1, MCP-1, and ICAM-1, and play anti-atherosclerosis and neuroprotective roles. Clinical Trial Registration: [clinicaltrials.gov], identifier [NCT02846207].

Buyang Huanwu decoction promotes angiogenesis of rat brain microvascular endothelial cells after oxygen-glucose deprivation reperfusion injury via activation of PI3K-AKT signaling pathway

OBJECTIVE

To investigate the effect and mechanism of Buyang Huanwu decoction (BYHWD) on angiogenesis of rat brain microvascular endothelial cells (RBMECs) after oxygen-glucose deprivation reperfusion (OGD/R) injury.

METHODS

RBMECs were pretreated with BYHWD containing serum 24 h before OGD/R injury was induced. Cells were randomly divided into blank control group, model control group, BYHWD group (provided BYHWD containing serum) and LY294002 group [treated with phosphoinositide 3-kinase (PI3K) inhibitor LY294002 for 1 h before provided BYHWD containing serum]. The cell viability, migration and tube formation abilities of RBMECs were detected by CCK-8, scratch wound healing, Transwell migration and tube formation assays, respectively. The protein expression levels of PI3K, p-PI3K, protein kinase B (AKT), p-AKT, hypoxia-inducible factor (HIF)-1α and vascular endothelial growth factor (VEGF) were determined by Western blotting.

RESULTS

Compared with model control group, cell viability, migration and tube formation abilities of RBMECs were significantly improved in BYHWD group (all P<0.01), the protein expression levels of p-PI3K, p-AKT, HIF-1α and VEGF were up-regulated (all P<0.05); while above effects were blocked by LY294002.

CONCLUSION

BYHWD can promote angiogenesis of RBMECs after OGD/R injury, which may be related to the increased protein expression of HIF-1α and VEGF through activation of PI3K-AKT signaling pathway.

Application and mechanism of anti-VEGF drugs in age-related macular degeneration

Age-related macular degeneration (AMD) is the leading cause of blindness in the elderly. The incidence rate increases with age in people over 50 years of age. With the advent of China’s aging society, the number of patients is increasing year by year. Although researchers have done a lot of basic research and clinical research on the pathogenesis and treatment of AMD in recent years, the pathogenesis of AMD is still controversialdue to the complexity of the disease itself. AMD is the primary cause of blindness in the elderly over 50 years old. It is characterized by the formation of choroidal neovascularization (CNV) and the over secretion of vascular endothelial growth factor (VEGF) as its main mechanism, which can eventually lead to vision loss or blindness. The occurrence and development of AMD is an extremely complex process, in which a large number of regulatory factors and cytokines are involved. Most of the existing treatments are for its concomitant CNV. Targeted VEGF drugs for neovascularization, such as Lucentis and Aflibercept, are the first-line drugs for AMD. Their application has greatly reduced the blinding rate of patients. However, there are still some patients who have no response to treatment or cannot maintain their vision after long-term treatment. Frequent injection also increases the risk of complications and economic burden. In order to further improve the quality of life and long-term prognosis of AMD patients, a variety of new treatmentshave been or will be applied in clinic, including combined treatment with the same or different targets to improve the curative effect, change or simplify the mode of medication, inhibit VEGF receptor tyrosine protein kinase and so on. This article provides a brief review of the research progress of anti-VEGF drugs and their mechanisms for the treatment of AMD, it is expected to provide a better treatment plan for AMD treatment.

Molecular mediators of angiogenesis and neurogenesis after ischemic stroke

The mechanisms governing neurological and functional recovery after ischemic stroke are incompletely understood. Recent advances in knowledge of intrinsic repair processes of the CNS have so far translated into minimal improvement in outcomes for stroke victims. Better understanding of the processes underlying neurological recovery after stroke is necessary for development of novel therapeutic approaches. Angiogenesis and neurogenesis have emerged as central mechanisms of post-stroke recovery and potential targets for therapeutics. Frameworks have been developed for conceptualizing cerebral angiogenesis and neurogenesis at the tissue and cellular levels. These models highlight that angiogenesis and neurogenesis are linked to each other and to functional recovery. However, knowledge of the molecular framework linking angiogenesis and neurogenesis after stroke is limited. Studies of potential therapeutics typically focus on one mediator or pathway with minimal discussion of its role within these multifaceted biochemical processes. In this article, we briefly review the current understanding of the coupled processes of angiogenesis and neurogenesis after stroke. We then identify the molecular mediators and signaling pathways found in pre-clinical studies to upregulate both processes after stroke and contextualizes them within the current framework. This report thus contributes to a more-unified understanding of the molecular mediators governing angiogenesis and neurogenesis after stroke, which we hope will help guide the development of novel therapeutic approaches for stroke survivors.

Neutrophil Immunomodulatory Activity of (−)-Borneol, a Major Component of Essential Oils Extracted from Grindelia squarrosa

Grindelia squarrosa (Pursh) Dunal is used in traditional medicine for treating various diseases; however, little is known about the immunomodulatory activity of essential oils from this plant. Thus, we isolated essential oils from the flowers (GEO_Fl) and leaves (GEO_Lv) of G. squarrosa and evaluated the chemical composition and innate immunomodulatory activity of these essential oils. Compositional analysis of these essential oils revealed that the main components were α-pinene (24.7 and 23.2% in GEO_Fl and GEO_Lv, respectively), limonene (10.0 and 14.7%), borneol (23.4 and 16.6%), p-cymen-8-ol (6.1 and 5.8%), β-pinene (4.0 and 3.8%), bornyl acetate (3.0 and 5.1%), trans-pinocarveol (4.2 and 3.7%), spathulenol (3.0 and 2.0%), myrtenol (2.5 and 1.7%), and terpinolene (1.7 and 2.0%). Enantiomer analysis showed that α-pinene, β-pinene, and borneol were present primarily as (−)-enantiomers (100% enantiomeric excess (ee) for (−)-α-pinene and (−)-borneol in both GEO_Fl and GEO_Lv; 82 and 78% ee for (−)-β-pinene in GEO_Fl and GEO_Lv), while limonene was present primarily as the (+)-enantiomer (94 and 96 ee in GEO_Fl and GEO_Lv). Grindelia essential oils activated human neutrophils, resulting in increased [Ca²⁺]_i (EC₅₀ = 22.3 µg/mL for GEO_Fl and 19.4 µg/mL for GEO_Lv). In addition, one of the major enantiomeric components, (−)-borneol, activated human neutrophil [Ca²⁺]_i (EC₅₀ = 28.7 ± 2.6), whereas (+)-borneol was inactive. Since these treatments activated neutrophils, we also evaluated if they were able to down-regulate neutrophil responses to subsequent agonist activation and found that treatment with Grindelia essential oils inhibited activation of these cells by the N-formyl peptide receptor 1 (FPR1) agonist fMLF and the FPR2 agonist WKYMVM. Likewise, (−)-borneol inhibited FPR-agonist-induced Ca²⁺ influx in neutrophils. Grindelia leaf and flower essential oils, as well as (−)-borneol, also inhibited fMLF-induced chemotaxis of human neutrophils (IC₅₀ = 4.1 ± 0.8 µg/mL, 5.0 ± 1.6 µg/mL, and 5.8 ± 1.4 µM, respectively). Thus, we identified (−)-borneol as a novel modulator of human neutrophil function.

Identification of (-)-bornyl diphosphate synthase from Blumea balsamifera and its application for (-)-borneol biosynthesis in Saccharomyces cerevisiae

Borneol is a precious monoterpenoid with two chiral structures, (-)-borneol and (+)-borneol. Bornyl diphosphate synthase is the key enzyme in the borneol biosynthesis pathway. Many (+)-bornyl diphosphate synthases have been reported, but no (-)-bornyl diphosphate synthases have been identified. Blumea balsamifera leaves are rich in borneol, almost all of which is (-)-borneol. In this study, we identified a high-efficiency (-)-bornyl diphosphate synthase (BbTPS3) from B. balsamifera that converts geranyl diphosphate (GPP) to (-)-bornyl diphosphate, which is then converted to (-)-borneol after dephosphorylation in vitro. BbTPS3 exhibited a K_m value of 4.93 ± 1.38 μM for GPP, and the corresponding k_cat value was 1.49 s⁻¹. Multiple strategies were applied to obtain a high-yielding (-)-borneol producing yeast strain. A codon-optimized BbTPS3 protein was introduced into the GPP high-yield strain MD, and the resulting MD-B1 strain produced 1.24 mg·L^-1 (-)-borneol. After truncating the N-terminus of BbTPS3 and adding a Kozak sequence, the (-)-borneol yield was further improved by 4-fold to 4.87 mg·L^-1. Moreover, the (-)-borneol yield was improved by expressing the fusion protein module of ERG20^F96W-N127W-YRSQI-t14-BbTPS3K2, resulting in a final yield of 12.68 mg·L^-1 in shake flasks and 148.59 mg·L^-1 in a 5-L bioreactor. This work is the first reported attempt to produce (-)-borneol by microbial fermentation.

Saposhnikoviae Radix Enhanced the Angiogenic and Anti-Inflammatory Effects of Huangqi Chifeng Tang in a Rat Model of Cerebral Infarction

Huangqi Chifeng Tang (HQCFT), a traditional Chinese formula of three herbs, has been used to treat cerebral infarction (CI). Saposhnikoviae Radix (SR) was designed as a guiding drug for HQCFT to improve its angiogenic and anti-inflammatory effects. In this study, TTC staining was used to detect the area of CI. H&E staining was used to detect the histopathologic changes in the cerebral tissue. Western blotting was performed to detect the protein expression of NLRP3, caspase 1, IL-1β, IL-6, TNF-α, MMP-9, VEGF, and VEGFR2 in cerebral tissue. Immunohistochemistry was used to detect the protein expression of MMP-9, VEGF, and VEGFR2. The contents of HIF-1α, NLRP3, caspase 1, IL-1β, IL-6, and TNF-α in the serum were determined by ELISA. Our study showed that HQCFT and HQCFT-SR could improve the pathological condition and reduce the infarcted area of the brain tissue in a rat model. In addition, HQCFT and HQCFT-SR significantly decreased the expression levels and serum contents of NLRP3, caspase 1, IL-1β, IL-6, and TNF-α; increased the expression levels of the VEGF and VEGFR2 proteins; and obviously reduced the serum content of HIF-1α. Importantly, the cytokines in brain tissue and serum from the HQCFT group exhibited better efficacy than those from the HQCFT-SR group. HQCFT exerted significant angiogenic and anti-inflammatory effects in rats subjected to middle cerebral artery occlusion (MCAO); these effects can be attributed to the guiding and enhancing effect of SR.

Multiple regulation and targeting effects of borneol in the neurovascular unit in neurodegenerative diseases

Efficient delivery of brain-targeted drugs is highly important for the success of therapies in neurodegenerative diseases. Borneol has several biological activities, such as anti-inflammatory and cell penetration enhancing effect, and can regulate processes in the neurovascular unit (NVU), such as protein toxic stress, autophagosome/lysosomal system, oxidative stress, programmed cell death and neuroinflammation. However, the influence of borneol on NVU in neurodegenerative diseases has not been fully explained. This study searched the keywords 'borneol', 'neurovascular unit', 'endothelial cell', 'astrocyte', 'neuron', 'blood-brain barrier', 'neurodegenerative diseases' and 'brain disease', in PubMed, BioMed Central, China National Knowledge Infrastructure (CNKI), and Bing search engines to explore the influence of borneol on NVU. In addition to the principle and mechanism of penetration of borneol in the brain, this study also showed its multiple regulation effects on NVU. Borneol was able to penetrate the blood-brain barrier (BBB), affecting the signal transmission between BBB and the microenvironment of the brain, down-regulating the expression of inflammatory and oxidative stress proteins in NVU, especially in microglia and astrocytes. In summary, borneol is a potential drug delivery agent for drugs against neurodegenerative diseases.

Progress in Borneol Intervention for Ischemic Stroke: A Systematic Review

Background: Borneol is a terpene and bicyclic organic compound that can be extracted from plants or chemically synthesized. As an important component of proprietary Chinese medicine for the treatment of stroke, its neuroprotective effects have been confirmed in many experiments. Unfortunately, there is no systematic review of these studies. This study aimed to systematically examine the neuroprotective effects of borneol in the cascade reaction of experimental ischemic stroke at different periods. Methods: Articles on animal experiments and cell-based research on the actions of borneol against ischemic stroke in the past 20°years were collected from Google Scholar, Web of Science, PubMed, ScienceDirect, China National Knowledge Infrastructure (CNKI), and other biomedical databases. Meta-analysis was performed on key indicators in vivo experiments. After sorting the articles, we focused on the neuroprotective effects and mechanism of action of borneol at different stages of cerebral ischemia. Results: Borneol is effective in the prevention and treatment of nerve injury in ischemic stroke. Its mechanisms of action include improvement of cerebral blood flow, inhibition of neuronal excitotoxicity, blocking of Ca²⁺ overload, and resistance to reactive oxygen species injury in the acute ischemic stage. In the subacute ischemic stage, borneol may antagonize blood-brain barrier injury, intervene in inflammatory reactions, and prevent neuron excessive death. In the late stage, borneol promotes neurogenesis and angiogenesis in the treatment of ischemic stroke. Conclusion: Borneol prevents neuronal injury after cerebral ischemia via multiple action mechanisms, and it can mobilize endogenous nutritional factors to hasten repair and regeneration of brain tissue. Because the neuroprotective effects of borneol are mediated by various therapeutic factors, deficiency caused by a single-target drug is avoided. Besides, borneol promotes other drugs to pass through the blood-brain barrier to exert synergistic therapeutic effects.