Tetramethylpyrazine Preserves the Integrity of Blood-Brain Barrier Associated With Upregulation of MCPIP1 in a Murine Model of Focal Ischemic Stroke

Bibliometric analysis of research progress on tetramethylpyrazine and its effects on ischemia-reperfusion injury

In recent decades, natural products have attracted worldwide attention and become one of the most important resources for pharmacological industries and medical sciences to identify novel drug candidates for disease treatment. Tetramethylpyrazine (TMP) is an alkaloid extracted from Ligusticum chuanxiong Hort., which has shown great therapeutic potential in cardiovascular and cerebrovascular diseases, liver and renal injury, as well as cancer. In this review, we analyzed 1270 papers published on the Web of Science Core Collection from 2002 to 2022 and found that TMP exerted significant protective effects on ischemia-reperfusion (I/R) injury that is the cause of pathological damages in a variety of conditions, such as ischemic stroke, myocardial infarction, acute kidney injury, and liver transplantation. TMP is limited in clinical applications to some extent due to its rapid metabolism, a short biological half-life and poor bioavailability. Obviously, the structural modification, administration methods and dosage forms of TMP need to be further investigated in order to improve its bioavailability. This review summarizes the clinical applications of TMP, elucidates its potential mechanisms in protecting I/R injury, provides strategies to improve bioavailability, which presents a comprehensive understanding of the important compound. Hopefully, the information and knowledge from this review can help researchers and physicians to better improve the applications of TMP in the clinic.

Synergistic amelioration between Ligusticum striatum DC and borneol against cerebral ischemia by promoting astrocytes-mediated neurogenesis

ETHNOPHARMACOLOGICAL RELEVANCE

Ligusticum chuanxiong Hort (LCH), with the accepted name of Ligusticum striatum DC in "The Plant List" database, is a widely used ethnomedicine in treating ischemic stroke, and borneol (BO) is usually prescribed with LCH for better therapy. Our previous study confirmed their synergistic effect on neurogenesis against cerebral ischemia. However, the underlying mechanism is still unclear.

AIM OF THE STUDY

More and more evidence indicated that astrocytes (ACs) might be involved in the modulation of neurogenesis via polarization reaction. The study was designed to explore the synergic mechanism between LCH and BO in promoting astrocyte-mediated neurogenesis.

MATERIALS AND METHODS

After primary cultures and identifications of ACs and neural stem cells (NSCs), the oxygen-glucose deprivation (OGD) model and the concentrations of LCH and BO were optimized. After the OGD-injured ACs were treated by LCH, BO, and their combination, the conditioned mediums were used to culture the OGD-injured NSCs. The proliferation, migration, and differentiation of NSCs were assessed, and the secretions of BDNF, CNTF, and VEGF from ACs were measured. Then the expressions of C3 and PTX3 were detected. Moreover, the mice were performed a global cerebral ischemia/reperfusion model and treated with LCH and (or) BO. After the assessments of Nissl staining, the expressions of Nestin, DCX, GFAP, C3, PTX3, p65 and p-p65 were probed.

RESULTS

The most appropriate duration of OGD for the injury of both NSCs and ACs was 6 h, and the optimized concentrations of LCH and BO were 1.30 μg/mL and 0.03 μg/mL, respectively. The moderate OGD environment induced NSCs proliferation, migration, astrogenesis, and neurogenesis, increased the secretions of CNTF and VEGF from ACs, and upregulated the expressions of C3 and PTX3. For the ACs, LCH further increased the secretions of BDNF and CNTF, enhanced PTX3 expression, and reduced C3 expression. Additionally, the conditioned medium from LCH-treated ACs further enhanced NSC proliferation, migration, and neurogenesis. The in vivo study showed that LCH markedly enhanced the Nissl score and neurogenesis, and decreased astrogenesis which was accompanied by downregulations of C3, p-p65, and p-p65/p65 and upregulation of PTX3. BO not only decreased the expression of C3 in ACs both in vitro and in vivo but also downregulated p-p65 and p-p65/p65 in vivo. Additionally, BO promoted the therapeutic effect of LCH for most indices.

CONCLUSION

A certain degree of OGD might induce ACs to stimulate the proliferation, astrogenesis, and neurogenesis of NSCs. LCH and BO exhibited a marked synergy in promoting ACs-mediated neurogenesis and reducing astrogenesis, in which LCH played a dominant role and BO boosted the effect of LCH. The mechanism of LCH might be involved in switching the polarization of ACs from A1 to A2, while BO preferred to inhibit the formation of A1 phenotype via downregulating NF-κB pathway.

Tetramethylpyrazine-loaded electroconductive hydrogels promote tissue repair after spinal cord injury by protecting the blood-spinal cord barrier and neurons

Spinal cord injury (SCI) usually induces profound microvascular dysfunction. It disrupts the integrity of the blood-spinal cord barrier (BSCB), which could trigger a cascade of secondary pathological events that manifest as neuronal apoptosis and axonal demyelination. These events can further lead to irreversible neurological impairments. Thus, reducing the permeability of the BSCB and maintaining its substructural integrity are essential to promote neuronal survival following SCI. Tetramethylpyrazine (TMP) has emerged as a potential protective agent for treating the BSCB after SCI. However, its therapeutic potential is hindered by challenges in the administration route and suboptimal bioavailability, leading to attenuated clinical outcomes. To address this challenge, traditional Chinese medicine, TMP, was used in this study to construct a drug-loaded electroconductive hydrogel for synergistic treatment of SCI. A conductive hydrogel combined with TMP demonstrates good electrical and mechanical properties as well as superior biocompatibility. Furthermore, it also facilitates sustained local release of TMP at the implantation site. Furthermore, the TMP-loaded electroconductive hydrogel could suppress oxidative stress responses, thereby diminishing endothelial cell apoptosis and the breakdown of tight junction proteins. This concerted action repairs BSCB integrity. Concurrently, myelin-associated axons and neurons are protected against death, which meaningfully restore neurological functions post spinal cord injury. Hence, these findings indicate that combining the electroconductive hydrogel with TMP presents a promising avenue for potentiating drug efficacy and synergistic repair following SCI.

Neuroprotective Effects of Melittin Against Cerebral Ischemia and Inflammatory Injury via Upregulation of MCPIP1 to Suppress NF-κB Activation In Vivo and In Vitro

Melittin, a principal constituent of honeybee venom, exhibits diverse biological effects, encompassing anti-inflammatory capabilities and neuroprotective actions against an array of neurological diseases. In this study, we probed the prospective protective influence of melittin on cerebral ischemia, focusing on its anti-inflammatory activity. Mechanistically, we explored whether monocyte chemotactic protein-induced protein 1 (MCPIP1, also known as ZC3H12A), a recently identified zinc-finger protein, played a role in melittin-mediated anti-inflammation and neuroprotection. Male C57/BL6 mice were subjected to distal middle cerebral artery occlusion to create a focal cerebral cortical ischemia model, with melittin administered intraperitoneally. We evaluated motor functions, brain infarct volume, cerebral blood flow, and inflammatory marker levels within brain tissue, employing quantitative real-time polymerase chain reaction, enzyme-linked immunosorbent assays, and western blotting. In vitro, an immortalized BV-2 microglia culture was stimulated with lipopolysaccharide (LPS) to establish an inflammatory cell model. Post-melittin exposure, cell viability, and cytokine expression were examined. MCPIP1 was silenced using siRNA in LPS-induced BV-2 cells, with the ensuing nuclear translocation of nuclear factor-κB assessed through cellular immunofluorescence. In vivo, melittin enhanced motor functions, diminished infarction, fostered blood flow restoration in ischemic brain regions, and markedly inhibited the expression of inflammatory cytokines (interleukin-1β, interleukin-6, tumor necrosis factor-α, and nuclear factor-κB). In vitro, melittin augmented MCPIP1 expression in LPS-induced BV-2 cells and ameliorated inflammation-induced cell death. The neuroprotective effect conferred by melittin was attenuated upon MCPIP1 knockdown. Our findings establish that melittin-induced tolerance to ischemic injury is intrinsically linked with its anti-inflammatory capacity. Moreover, MCPIP1 is, at the very least, partially implicated in this process.

Neuroprotection by tetramethylpyrazine and its synthesized analogues for central nervous system diseases: a review

BACKGROUND

Due to the global increase in aging populations and changes in modern lifestyles, the prevalence of neurodegenerative diseases, cerebrovascular disorders, neuropsychiatrcic conditions, and related ailments is rising, placing an increasing burden on the global public health system.

MATERIALS AND METHODS

All studies on tetramethylpyrazine (TMP) and its derivatives were obtained from reputable sources such as PubMed, Elsevier, Library Genesis, and Google Scholar. Comprehensive data on TMP and its derivatives was meticulously compiled.

RESULTS

This comprehensive analysis explains the neuroprotective effects demonstrated by TMP and its derivatives in diseases of the central nervous system. These compounds exert their influence on various targets and signaling pathways, playing crucial roles in the development of various central nervous system diseases. Their multifaceted mechanisms include inhibiting oxidative damage, inflammation, cell apoptosis, calcium overload, glutamate excitotoxicity, and acetylcholinesterase activity.

CONCLUSION

This review provides a brief summary of the most recent advancements in research on TMP and its derivatives in the context of central nervous system diseases. It involves synthesizing analogs of TMP and evaluating their effectiveness in models of central nervous system diseases. The ultimate goal is to facilitate the practical application of TMP and its derivatives in the future treatment of central nervous system diseases.

Synthesis and bioevaluation of Scutellarein-Tertramethylpyrazine hybrid molecules for the treatment of ischemic stroke

Ischemic stroke caused by insufficient blood supply to the brain may produce a sequence of cascade reactions, leading to oxidative stress and ultimately inducing nerve cell damage. Therefore, hybrid molecules with multiple therapeutic effects have irreplaceable advantages for the treatment of ischemic stroke. Based on the previous works, two types of Scutellarein and Tertramethylpyrazine hybrid molecules were designed and synthesized according to the PepT 1-based design. After systematic research, all synthesized hybrid molecules exhibited more excellent neuroprotective effect and antiplatelet activity compared to the original drugs. Among them, the selected compound 1e with superior neuroprotective and antiplatelet effects could significantly enhance the permeability on the Caco-2 monolayer membrane and inhibit the Gly-Sar uptake on Caco-2 cells. Meanwhile, the result of intestinal perfusion has also confirmed that the absorption of the selected compound 1e is indeed increased. Further, the selected compound 1e significantly reduce the cerebral infarction volume of middle cerebral artery occlusion/reperfusion rats. Especially, the cerebral infarction volume of the high-dose 1e group reduced to one fourth of the model group. Meanwhile, results of hematoxylin-eosin staining also indicated that the damage in the hippocampus CA1 region was significantly alleviated after treatment with the compound 1e. Accordingly, molecular hybridization strategy is one of the simple and feasible ways to improve the therapeutic effect of single targeted drug.

Bone marrow mesenchymal stem cells-derived exosomes mediated delivery of tetramethylpyrazine attenuate cerebral ischemic injury

OBJECTIVES

Tetramethylpyrazine (TEP) can protect the brain from ischemic damage, but it has defects such as short half-life, fast absorption, wide distribution, and rapid elimination, which limits its application. Exosomes (Exos) have the property of loading drugs and transporting signal substances. Here, we elucidated the effect of TEP-loaded bone marrow mesenchymal stem cell (BMSC)-derived Exos (Exo-TEP) on cerebral ischemic injury.

MATERIALS AND METHODS

The Exos were extracted by ultracentrifugation and TEP was loaded into the Exos by electroporation. Oxygen-glucose deprivation (OGD) induced-primary cortical neurons and middle cerebral artery occlusion (MCAO)-induced mouse models were used to determine the effect of Exo-TEP on cerebral ischemic injury in vitro and in vivo.

RESULTS

Exo-TEP exhibited a stable and sustained release pattern compared to free TEP. Exo-TEP treatment was more significant in improving OGD-mediated decrease in cell activity, as well as a elevation in apoptosis and ROS production in cortical neurons. In comparison with Exo and free TEP treatment, Exo-TEP treatment significantly improved pathological changes, shrunk cerebral infarction volume, as well reduced neurological deficit scores and neuronal apoptosis, and oxidative stress.

CONCLUSIONS

Exo-TEP was superior to free TEP in improving cerebral ischemic injury by reducing neuronal apoptosis and oxidative stress.

Huoluo Xiaoling Pellet promotes microglia M2 polarization through increasing MCPIP1 expression for ischemia stroke alleviation

Huoluo Xiaoling Pellet (HXP), a Chinese patent medicine, is commonly administered for the treatment of treat ischemic strokes. MCPIP1, an inducible suppressor of the inflammatory response, is a regulator of microglial M2 polarization. This study aimed to explore whether HXP can promote microglial M2 polarization by upregulating MCPIP1 expression, consequently mitigating cerebral ischemic injury. Our study involved 85 Sprague-Dawley rats (weighing 250-280 g). We established middle cerebral artery occlusion (MCAO) and oxygen-glucose deprivation-reoxygenation (OGD/R) models with MCPIP1 knockdown to assess the effects of HXP on ischemic strokes. Our findings show that HXP reduced brain water content, improved neurological function, and inhibited the expression of inflammatory factors in the brain tissues of MCAO rats. The neuroprotective effects of HXP on cerebral ischemic injuries were compromised by MCPIP1 knockdown. Immunofluorescence results indicated that the expression of microglia marker Iba1 and M2 phenotypic marker CD206 was upregulated in MCAO rats and OGD/R-treated microglia. Administration of HXP significantly reduced Iba1 expression and facilitated CD206 expression, an effect that was counteracted by sh-MCPIP1 transfection. Western blotting revealed that HXP treatment augmented the expression of MCPIP1, microglial M2 marker proteins (CD206 and Arg1), and PPARγ, while reducing the expression of microglial M1 marker proteins (CD16 and iNOS) in MCAO rats and OGD/R-induced microglia. MCPIP1 knockdown suppressed HXP-mediated upregulation of MCPIP1, CD206, Arg1, and PPARγ, as well as the downregulation of CD16 and iNOS. Our findings suggest that HXP primarily ameliorates ischemic stroke through the upregulation of MCPIP1, which in turn induces microglial M2 polarization.

Neuroprotective Strategies for Stroke by Natural Products: Advances and Perspectives

Cerebral ischemic stroke is a disease with high prevalence and incidence. Its management focuses on rapid reperfusion with intravenous thrombolysis and endovascular thrombectomy. Both therapeutic strategies reduce disability, but the therapy time window is short, and the risk of bleeding is high. Natural products (NPs) have played a key role in drug discovery, especially for cancer and infectious diseases. However, they have made little progress in clinical translation and pose challenges to the treatment of stroke. Recently, with the investigation of precise mechanisms in cerebral ischemic stroke and the technological development of NP-based drug discovery, NPs are addressing these challenges and opening up new opportunities in cerebral stroke. Thus, in this review, we first summarize the structure and function of diverse NPs, including flavonoids, phenols, terpenes, lactones, quinones, alkaloids, and glycosides. Then we propose the comprehensive neuroprotective mechanism of NPs in cerebral ischemic stroke, which involves complex cascade processes of oxidative stress, mitochondrial damage, apoptosis or ferroptosis-related cell death, inflammatory response, and disruption of the blood-brain barrier (BBB). Overall, we stress the neuroprotective effect of NPs and their mechanism on cerebral ischemic stroke for a better understanding of the advances and perspective in NPs application that may provide a rationale for the development of innovative therapeutic regimens in ischemic stroke.

Regulatory mechanisms of tetramethylpyrazine on central nervous system diseases: A review

Central nervous system (CNS) diseases can lead to motor, sensory, speech, cognitive dysfunction, and sometimes even death. These diseases are recognized to cause a substantial socio-economic impact on a global scale. Tetramethylpyrazine (TMP) is one of the main active ingredients extracted from the Chinese herbal medicine Ligusticum striatum DC. (Chuan Xiong). Many in vivo and in vitro studies have demonstrated that TMP has a certain role in the treatment of CNS diseases through inhibiting calcium ion overload and glutamate excitotoxicity, anti-oxidative/nitrification stress, mitigating inflammatory response, anti-apoptosis, protecting the integrity of the blood-brain barrier (BBB) and facilitating synaptic plasticity. In this review, we summarize the roles and mechanisms of action of TMP on ischemic cerebrovascular disease, spinal cord injury, Parkinson’s disease, Alzheimer’s disease, cognitive impairments, migraine, and depression. Our review will provide new insights into the clinical applications of TMP and the development of novel therapeutics.

Tetramethylpyrazine: A review on its mechanisms and functions

Ligusticum chuanxiong Hort (known as Chuanxiong in China, CX) is one of the most widely used and long-standing medicinal herbs in China. Tetramethylpyrazine (TMP) is an alkaloid and one of the active components of CX. Over the past few decades, TMP has been proven to possess several pharmacological properties. It has been used to treat a variety of diseases with excellent therapeutic effects. Here, the pharmacological characteristics and molecular mechanism of TMP in recent years are reviewed, with an emphasis on the signal-regulation mechanism of TMP. This review shows that TMP has many physiological functions, including anti-oxidant, anti-inflammatory, and anti-apoptosis properties; autophagy regulation; vasodilation; angiogenesis regulation; mitochondrial damage suppression; endothelial protection; reduction of proliferation and migration of vascular smooth muscle cells; and neuroprotection. At present, TMP is used in treating cardiovascular, nervous, and digestive system conditions, cancer, and other conditions and has achieved good curative effects. The therapeutic mechanism of TMP involves multiple targets, multiple pathways, and bidirectional regulation. TMP is, thus, a promising drug with great research potential.

Ligustrazine alleviates psoriasis-like inflammation through inhibiting TRAF6/c-JUN/NFκB signaling pathway in keratinocyte

Ligusticum chuanxiong Hort (Ligusticum; Apiaceae) (accepted name, Ligusticum striatum DC, on "The Plant List" for the latest version) is a Chinese herbal medicine (CHM) which mainly distributed in Sichuan Basin, China. Chuanxiong is the dried rhizome of Ligusticum chuanxiong Hort. Ligustrazine, also known as tetramethylpyrazine (TMP), is a main active fraction of chuanxiong. The aim of this study was to clarify the underlying mechanisms by which TMP protect against psoriasis-like inflammation in keratinocytes. Here, we demonstrated that TMP alleviated the severity and PASI scores of IMQ-induced psoriasis-like skin lesion in vivo. For the histopathology level, TMP inhibited the over-proliferation of keratinocytes in the epidermis and the substantial immune cells influx in dermis. For the mechanism of the ability of TMP on regulating inflammation, we confirmed that TMP regulate the TRAF6/c-JUN/NFκB signaling pathway through analyzing the proteomics profiling and verifying the expression of TRAF6, pho-c-Jun, pho-NFκB, so that the downstream psoriasis-relevant genes transcribed by c-JUN or NFκB were down-regulated. Furthermore, we predicted TRAF6 as the potential binding point of TMP. Accordingly, our study demonstrated that TMP regulated psoriasis-like inflammation through inhibiting TRAF6/c-JUN/NFκB signaling pathway in keratinocytes, which potentially provides evidence of the mechanism of TMP in the treatment and prevention of psoriasis.

Altered Blood Brain Barrier Permeability and Oxidative Stress in Cntnap2 Knockout Rat Model

Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by three core symptoms, specifically impaired social behavior, stereotypic/repetitive behaviors, and sensory/communication deficits. Although the exact pathophysiology of ASD is still unknown, host genetics, oxidative stress, and compromised blood brain barrier (BBB) have been implicated in predisposition to ASD. With regards to genetics, mutations in the genes such as CNTNAP2 have been associated with increased susceptibility of developing ASD. Although some studies observed conflicting results suggesting no association of CNTNAP2 with ASD, other investigations correlated this gene with autism. In addition, CNTNAP2 mediated signaling is generally considered to play a role in neurological disorders due to its critical role in neurodevelopment, neurotransmission, and synaptic plasticity. In this investigation, we studied BBB integrity and oxidative stress in Cntnap2^−/− rats. We observed that the BBB permeability was significantly increased in Cntnap2^−/− rats compared to littermate wild-type (WT) animals as determined by FITC-dextran and Evans blue assay. High levels of thiobarbituric acid reactive substances and lower amounts of reduced glutathione were observed in brain homogenates of Cntnap2^−/− rats, suggesting oxidative stress. Brain sections from Cntnap2^−/− rats showed intense inducible nitric oxide synthase immunostaining, which was undetectable in WT animals. Quantification of nitric oxide in brain homogenates revealed significantly high levels in Cntnap2^−/− rats compared to the control group. As increased permeability of the BBB and oxidative stress have been observed in ASD individuals, our results suggest that Cntnap2^−/− rats have a high construct and face validity and can be explored to develop effective therapeutic modalities.

Uncovering the Mechanism of Chuanhong Stroke Capsule in the Treatment of Stroke Based on Network Pharmacology and Molecular Docking Technology

Background and Objective: Chuanhong Stroke Capsule (CHSC) has good clinical efficacy in the treatment of cerebral ischemic stroke (CIS) patients. This study aimed to investigate the pharmacological mechanisms of CHSC in treating CIS using bioinformatics. Methods: The active compounds of CHSC were screened by searching Traditional Chinese Medicine System Pharmacological Database and Analysis Platform (TCMSP), Swiss absorption, distribution, metabolism, and excretion (ADME), PubMed, and China National Knowledge Infrastructure (CNKI) databases. Besides, the potential targets of active compounds were obtained through TCMSP and Swiss Target Prediction databases. CIS targets were obtained from GeneCards, Online Mendelian Inheritance in Man (OMIM), and Gene Expression Omnibus (GEO) databases. CHSC-CIS intersection targets were identified by matching the two, and prediction and analysis of biological functions and pathways of intersection targets was used the enrichments of gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG). Furthermore, protein–protein interaction (PPI) network, herb-target, and compound-target network of CHSC-CIS were constructed by Cytoscape3.7.2, and herb-compound-pathway network was drawn with Sankey diagram. Finally, AutoDock was used for molecular docking verification, and identifying the active binding sites in target proteins. Results: A total of 293 putative targets were obtained from 62 active compounds in CHSC. Among them, 209 targets were related to CIS. PPI network showed that the top 16 key targets were RELA, JUN, FOS, MAPK1, AKT1, etc. KEGG pathway enrichment analysis demonstrated that CHSC was enriched in PI3K-Akt, MAPK, and TNF signaling pathways. In addition, GO enrichment analysis showed the significant enrichment of CHSC in the following categories: kinase binding, cellular response to nitrogen compound, etc. Network topology analysis showed that quercetin, luteolin, kaempferol, etc., were the key components in CHSC. Finally, molecular docking studies suggested that the active components in CHSC had a good binding ability with the key targets. Conclusions: Our study demonstrated that CHSC exerted the effect in treating CIS by the characteristics of multi-target and multi-pathway, thereby providing a theoretical basis for further study of the effective components and mechanism of CHSC in the treatment of CIS.