Discovery of tetrahydropalmatine and protopine regulate the expression of dopamine receptor D2 to alleviate migraine from Yuanhu Zhitong formula

α7nAChR-mediated astrocytic activation: A novel mechanism of Xiongzhi Dilong decoction in ameliorating chronic migraine

ETHNOPHARMACOLOGICAL RELEVANCE

Alpha 7 nicotinic acetylcholine receptor (α7nAChR)-mediated astrocytic activation is closely related to central sensitization of chronic migraine (CM). Xiongzhi Dilong decoction (XZDL), originated from Xiongzhi Shigao decoction of Yi-zong-jin-jian, has been confirmed to relieve CM in experiment and clinic. However, its underlying mechanism for treating CM has not been elucidated.

AIM OF THE STUDY

To reveal the underlying mechanisms of XZDL to alleviate CM in vivo focusing mainly on α7nAChR-mediated astrocytic activation and central sensitization in TNC.

MATERIALS AND METHODS

CM rat model was established by subcutaneous injection of nitroglycerin (NTG) recurrently, and treated with XZDL simultaneously. Migraine-like behaviors of rats (ear redness, head scratching, and cage climbing) and pain-related reactions (mechanical hind-paw withdrawal threshold) of rats were evaluated before and after NTG injection and XZDL administration at different points in time for nine days. The immunofluorescence single and double staining were applied to detect the levels of CGRP, c-Fos, GFAP and α7nAChR in NTG-induced CM rats. ELISA kits were employed to quantify levels of TNF-α, IL-1β, and IL-6 in medulla oblongata of CM rats. The expression levels of target proteins were examined using western blotting. Finally, methyllycaconitine citrate (MLA, a specific antagonist of α7nAChR) was applied to further validate the mechanisms of XZDL in vivo.

RESULTS

XZDL significantly attenuated the pain-related behaviors of the NTG-induced CM rats, manifesting as constraints of aberrant migraine-like behaviors including elongated latency of ear redness and decreased numbers of head scratching and cage climbing, and increment of mechanical withdrawal threshold. Moreover, XZDL markedly lowered levels of CGRP and c-Fos, as well as inflammatory cytokines (IL-1β, IL-6 and TNF-α) in CM rats. Furthermore, XZDL significantly enhanced α7nAChR expression and its co-localization with GFAP, while markedly inhibited the expression of GFAP and the activation of JAK2/STAT3/NF-κB pathway in the TNC of CM rats. Finally, blocking α7nAChR with MLA reversed the effects of XZDL on astrocytic activation, central sensitization, and the pain-related behaviors in vivo.

CONCLUSION

XZDL inhibited astrocytic activation and central sensitization in NTG-induced CM rats by facilitating α7nAChR expression and suppressing JAK2/STAT3/NF-κB pathway, implying that the regulation of α7nAChR-mediated astrocytic activation represents a novel mechanism of XZDL for relieving CM.

Omics-based pharmacological evaluation reveals Yuanhu Zhitong oral liquid ameliorates arthritis by regulating PKC/ERK/NF-κB signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Successful use of herbal medicine in the treatment of rheumatoid arthritis (RA) creates opportunities for alternative therapies. Yuanhu Zhitong oral liquid (YZOL) is an herbal preparation known for its potent analgesic and anti-inflammatory properties in traditional use. However, the pharmacological mechanism of YZOL for treating RA remains unclear.

AIM OF THE STUDY

The aim of this study was to evaluate the efficacy of YZOL in the treatment of RA and to explore its potential mechanisms through omics analysis.

MATERIALS AND METHODS

Type II collagen was used to induce an arthritis rat model. The effects of YZOL on paw swelling, inflammatory cytokines, oxidative stress, and histopathological changes were systematically investigated. A pathway-driven transcriptomic analysis was performed to identify key signaling pathways associated with YZOL therapy. The key alterations were validated by qRT-PCR, Western blot, and immunohistochemistry assays.

RESULTS

YZOL significantly attenuated arthritis progression, reduced paw swelling rate, and lowered arthritis score in CIA rats. YZOL also inhibited systemic inflammation and associated oxidative stress during RA. Transcriptomic analysis identified 341 genes with significantly altered expression following YZOL treatment. These genes were enriched in inflammation-related pathways, particularly in the NF-κB and MAPK signaling pathways. In addition, we discovered that YZOL can alleviate inflammation in the local synovial tissue. The effect of YZOL was confirmed by the suppression of PKC/ERK/NF-κB p65 signaling at systemic and local levels.

CONCLUSIONS

This study provides novel evidence that YZOL treatment ameliorates RA by suppressing the PKC/ERK/NF-κB pathway, suggesting its potential as an alternative therapy for RA.

Current advances in the pain treatment and mechanisms of Traditional Chinese Medicine

Traditional Chinese Medicine (TCM), as a unique medical model in China, has been shown to be effective in the treatment of many diseases. It has been proven that TCM can increase the pain threshold, increase the level of endorphins and enkephalins in the body, and reduce the body's response to adverse stimuli. In recent years, TCM scholars have made valuable explorations in the field of pain treatment, using methods such as internal and external application of TCM and acupuncture to carry out research on pain treatment and have achieved more satisfactory results. TCM treats pain in a variety of ways, and with the discovery of a variety of potential bioactive substances for pain treatment. With the new progress in the research of other TCM treatment methods for pain, TCM will have greater potential in the clinical application of pain.

Variations of the fungal microbiome in Corydalis Rhizoma with different collection areas, processing methods, and storage conditions

Corydalis Rhizoma (CR, Yanhusuo in Chinese) has been widely used as an analgesic in herbal medicine and functional food. Cases of fungal and mycotoxin contamination in CR have been reported. In this study, the composition and diversity of fungal microbiome in CR samples from four herbal markets and two processing methods were investigated by DNA metabarcoding. Variations of the fungal microbiome in CR during cold and conventional storage were monitored. Results showed that Aspergillus was the dominant genus and saprotroph was the dominant trophic mode. Six potential toxigenic fungi, namely, Aspergillus fumigatus, Aspergillus ostianus, Aspergillus terreus, Penicillium citrinum, Penicillium oxalicum, and Trichothecium roseum, were detected. Differences in fungal composition and diversity among various groups based on collection areas and processing methods were also observed. Moreover, the relative abundance of dominant genera in CR samples stored at different temperatures was significantly different and changed with storage time. This study is the first to reveal the influence of collection areas, processing methods, and storage conditions on the fungal microbiome in CR, which was expected to provide a basis for control strategies of fungal contamination in the industrial chain of CR.

In vitro drug screening models derived from different PC12 cell lines for exploring Parkinson's disease based on electrochemical signals of catecholamine neurotransmitters

Gold nanostructures and a Nafion modified screen-printed carbon electrode (Nafion/AuNS/SPCE) were developed to assess the cell viability of Parkinson's disease (PD) cell models. The electrochemical measurement of cell viability was reflected by catecholamine neurotransmitter (represented by dopamine) secretion capacity, followed by a traditional tetrazolium-based colorimetric assay for confirmation. Due to the  capacity to synthesize, store, and release catecholamines as well as their unlimited homogeneous proliferation, and ease of manipulation, pheochromocytoma (PC12) cells were used for PD cell modeling. Commercial low-differentiated and highly-differentiated PC12 cells, and home-made nerve growth factor (NGF) induced low-differentiated PC12 cells (NGF-differentiated PC12 cells) were included in the modeling. This approach achieved sensitive and rapid determination of cellular modeling and intervention states. Notably, among the three cell lines, NGF-differentiated PC12 cells displayed the enhanced neurotransmitter secretion level accompanied with attenuated growth rate, incremental dendrites in number and length that were highly resemble with neurons. Therefore, it was selected as the PD-tailorable modeling cell line. In short, the electrochemical sensor can be used to sensitively determine the biological function of neuron-like PC12 cells with negligible destruction and to explore the protective and regenerative impact of various substances on nerve cell model.

Based on spinal central sensitization creating analgesic screening approach to excavate anti-neuropathic pain ingredients of Corydalis yanhusuo W.T.Wang

ETHNOPHARMACOLOGICAL RELEVANCE

Corydalis Rhizome (RC) as a traditional analgesic Chinese medicine is the dried tuber of Corydalis yanhusuo W.T.Wang. Many efforts have revealed that RC could effectively alleviate neuropathic pain, while its active ingredients in neuropathic pain are still not clear.

AIM OF THE STUDY

Spinal central sensitization contributes greatly to neuropathic pain, and neuron, astrocyte and microglia play important roles in spinal central sensitization. The aim of the present study is to excavate active compounds in RC regulating spinal central sensitization to inhibit neuropathic pain.

MATERIALS AND METHODS

Immunofluorescence and western blotting were used to determine protein expression levels. Gene expression levels were detected by RT-PCR. PC12 neuronal cells, C6 astrocyte cells, and BV2 microglia cells were cultured for in vitro studies. Targeting multi types of cells extraction combined with HPLC-Q-TOF-MS/MS was established to identify components binding to above cells. Animal studies were used to verify the analgesic activities of components.

RESULTS

Total alkaloids of RC (RC-TA) significantly relieved neuropathic pain in chronic constriction injury (CCI) rats and repressed spinal central sensitization. Eight components of RC-TA were found to bind to PC12, C6, or BV2 cells. They could respectively suppress the activation of cells in vitro and alleviate CCI-induced neuropathic pain, among which glaucine and dehydrocorydaline induced antinociception was stronger than l-THP. Meanwhile, glaucine had no effect on acute or chronic inflammatory pain, and its antinociception in neuropathic pain could be abolished by dopamine D1 receptor agonist.

CONCLUSIONS

Employing multi types of cells based on spinal central sensitization rather than single cell may allow for more thorough excavation of active substances. Glaucine was firstly found could attenuate neuropathic pain but not other types of pain which indicated that different alkaloids in RC exert distinct analgesic effects on different pain models, and gluacine has the potential to be developed as an analgesic drug specifically for neuropathic pain relieving.

The composition, pharmacological effects, related mechanisms and drug delivery of alkaloids from Corydalis yanhusuo

Corydalis yanhusuo W. T. Wang, also known as yanhusuo, yuanhu, yanhu and xuanhu, is one of the herb components of many Chinese Traditional Medicine prescriptions such as Jin Ling Zi San and Yuanhu-Zhitong priscription. C. yanhusuo was traditionally used to relieve pain and motivate blood and Qi circulation. Now there has been growing interest in pharmacological effects of alkaloids, the main bioactive components of C. yanhusuo. Eighty-four alkaloids isolated from C. yanhusuo are its important bioactive components and can be characterized into protoberberine alkaloids, aporphine alkaloids, opiate alkaloids and others and proper extraction or co-administration methods modulate their contents and efficacy. Alkaloids from C. yanhusuo have various pharmacological effects on the nervous system, cardiovascular system, cancer and others through multiple molecular mechanisms such as modulating neurotransmitters, ion channels, gut microbiota, HPA axis and signaling pathways and are potential treatments for many diseases. Plenty of novel drug delivery methods such as autologous red blood cells, self-microemulsifying drug delivery systems, nanoparticles and others have also been investigated to better exert the effects of alkaloids from C. yanhusuo. This review summarized the alkaloid components of C. yanhusuo, their pharmacological effects and mechanisms, and methods of drug delivery to lay a foundation for future investigations.

Frankincense-Myrrh treatment alleviates neuropathic pain via the inhibition of neuroglia activation mediated by the TLR4/MyD88 pathway and TRPV1 signaling

BACKGROUND

Neuroglia are important modulators of neuronal functionality, and thus play an integral role in the pathogenesis and treatment of neuropathic pain (NP). According to traditional Chinese medicine, Frankincense-Myrrh is capable of "activating blood and dissipating blood stasis", and as such these two biological compounds are commonly used to treat NP, however, the mechanisms underlying the efficacy of such treatment are unclear.

PURPOSE

This study aimed to further elucidate the protective effects associated with the Frankincense-Myrrh treatment of NP.

METHODS

A chronic sciatic nerve compression injury (CCI) model of NP was established, after which animals were gavaged with Frankincense, Myrrh, Frankincense-Myrrh, or the positive control drug pregabalin for 14 days. Network pharmacology approaches were used to identify putative pathways and targets associated with the Frankincense-Myrrh-mediated treatment of NP, after which these targets were subjected to in-depth analyses. The impact of TLR4 blockade on NP pathogenesis was assessed by intrathecally administering a TLR4 antagonist (LRU) or the MyD88 homodimerization inhibitory peptide (MIP).

RESULTS

Significant alleviation of thermal and mechanical hypersensitivity in response to Frankincense and Myrrh treatment was observed in NP model mice, while network pharmacology analyses suggested that the pathogenesis of NP may be related to TLR4/MyD88-mediated neuroinflammation. Consistently, Frankincense-Myrrh treatment was found to reduce TLR4, MyD88, and p-p65 expression in spinal dorsal horn neuroglia from treated animals, in addition to inhibiting neuronal TRPV1 and inflammatory factor expression. Intrathecal LRU and MIP delivery were sufficient to alleviate thermal and mechanical hyperalgesia in these CCI model mice, with concomitant reductions in neuronal TRPV1 expression and neuroglial activation in the spinal dorsal horn.

CONCLUSION

These data suggest that Frankincense-Myrrh treatment was sufficient to alleviate NP in part via inhibiting TLR4/MyD88 pathway and TRPV1 signaling activity. Blocking TLR4 and MyD88 activation may thus hold value as a means of treating NP.

Protopine alleviates lipopolysaccharide-triggered intestinal epithelial cell injury through retarding the NLRP3 and NF-κB signaling pathways to reduce inflammation and oxidative stress

BACKGROUND

Inflammatory bowel disease (IBD) is a common chronic intestinal disease. Protopine isolated from different plants has been investigated to understand its special functions on varied diseases. However, the regulatory effects of protopine on the progression of IBD remain unclear. Our study is aimed to explore the effects of protopine on the progression of IBD and its underlying regulatory mechanism of action.

METHODS

The cell viability was assessed through MTT colorimetric assay. The protein expressions of genes were examined by Western blot analysis. The cell apoptosis and reactive oxygen species level were measured using flow cytometry. The levels of inflammation and oxidative stress-related proteins were tested through enzyme-linked-immunosorbent serologic assay. The intracellular Ca²⁺ concentration and mitochondrial membrane potential were measured through immunofluorescence assay.

RESULTS

First, different concentrations of lipopolysaccharide (LPS) were treated with NCM460 cells to establish IBD cell model, and 5-μg/mL LPS was chosen for followed experiments. In this study, we discovered that protopine relieved the LPS-induced inhibited intestinal epithelial cell viability and enhanced cell apoptosis. Moreover, protopine attenuated LPS-stimulated inflammation activation and oxidative stress. Further experiments illustrated that the increased intracellular Ca²⁺ concentration and decreased mitochondrial membrane potential stimulated by LPS were reversed by protopine treatment. Finally, through Western blot analysis, it was demonstrated that protopine retarded the activated NLR family pyrin domain containing 3 (NLRP3) and nuclear factor kappa B (NF-κB) signaling pathways mediated by LPS.

CONCLUSION

Protopine alleviated LPS-triggered intestinal epithelial cell injury by inhibiting NLRP3 and NF-κB signaling pathways to reduce inflammation and oxidative stress. This discovery may provide a useful drug for treating IBD.

Acute, chronic, and genotoxic studies on the protopine total alkaloids of the Macleaya cordata (willd.) R. Br. in rodents

The protopine alkaloids are widely distributed within the opium poppy family and have a wide range of pharmacological effects. MPTA is a product of the protopine total alkaloids extracted from the Macleaya cordata (Willd.) R. Br. Previously, we reported good anti-inflammatory activity of MPTA as well as oral acute and sub-chronic toxicity studies in rats. In order to perform a systematic toxicological safety assessment of MPTA, oral acute toxicity, genotoxicity (bone marrow cell chromosome aberration test, sperm abnormality test, bone marrow cell micronucleus test, and rat teratogenicity test), and chronic toxicity in mice were performed in this study. In the oral acute toxicity test, the LD₅₀ in ICR mice was 481.99 mg/kg, with 95% confidence limits ranging from 404.27 to 574.70 mg/kg. All three mutagenicity tests tested negative in the range of 60.25–241.00 mg/kg. The results of the teratogenicity test in rats showed no reproductive or embryonic developmental toxicity at only 7.53 mg/kg, which can be considered as a no observed effect level (NOEL) for the teratogenicity test. Therefore, MPTA is safe for use at the doses tested, but attention should be paid to the potential risk to pregnant animals and the safety evaluation and toxicity mechanisms in target animals should be further investigated.

Discovery of anti-stroke active substances in Guhong injection based on multi-phenotypic screening of zebrafish

Ischemic stroke is a leading cause of death worldwide, and it remains an urgent task to develop novel and alternative therapeutic strategies for the disease. We previously reported the positive effects of Guhong injection (GHI), composed of safflower extract and aceglutamide, in promoting functional recovery in ischemic stroke mice. However, the active substances and pharmacological mechanism of GHI is still elusive. Aiming to identify the active anti-stroke components in GHI, here we conducted a multi-phenotypic screening in zebrafish models of phenylhydrazine-induced thrombosis and ponatinib-induced cerebral ischemia. Peripheral and cerebral blood flow was quantified endogenously in erythrocytes fluorescence-labeled thrombosis fish, and baicalein and rutin were identified as major anti-thrombotic substances in GHI. Moreover, using a high-throughput video-tracking system, the effects of locomotion promotion of GHI and its main compounds were analyzed in cerebral ischemia model. Chlorogenic acid and gallic acid showed significant effects in preventing locomotor dyfunctions. Finally, GHI treatment greatly decreased the expression levels of coagulation factors F7 and F2, NF-κB and its mediated proinflammatory cytokines in the fish models. Molecular docking suggested strong affinities between baicalein and F7, and between active substances (baicalein, chlorogenic acid, gallic acid, and rutin) and NF-κB p65. In summary, our findings established a novel drug discovery method based on multi-phenotypic screening of zebrafish, provided endogenous evidences of GHI in preventing thrombus formation and promoting behavioral recovery after cerebral ischemia, and identified baicalein, rutin, chlorogenic acid, and gallic acid as active compounds in the management of ischemic stroke.

Dopamine receptor D2 regulates GLUA1-containing AMPA receptor trafficking and central sensitization through the PI3K signaling pathway in a male rat model of chronic migraine

Background

The pathogenesis of chronic migraine remains unresolved. Recent studies have affirmed the contribution of GLUA1-containing AMPA receptors to chronic migraine. The dopamine D2 receptor, a member of G protein-coupled receptor superfamily, has been proven to have an analgesic effect on pathological headaches. The present work investigated the exact role of the dopamine D2 receptor in chronic migraine and its effect on GLUA1-containing AMPA receptor trafficking.

Methods

A chronic migraine model was established by repeated inflammatory soup stimulation. Mechanical, periorbital, and thermal pain thresholds were assessed by the application of von Frey filaments and radiant heat. The mRNA and protein expression levels of the dopamine D2 receptor were analyzed by qRT‒PCR and western blotting. Colocalization of the dopamine D2 receptor and the GLUA1-containing AMPAR was observed by immunofluorescence. A dopamine D2 receptor agonist (quinpirole) and antagonist (sulpiride), a PI3K inhibitor (LY294002), a PI3K pathway agonist (740YP), and a GLUA1-containing AMPAR antagonist (NASPM) were administered to confirm the effects of the dopamine D2 receptor, the PI3K pathway and GULA1 on central sensitization and the GLUA1-containing AMPAR trafficking. Transmission electron microscopy and Golgi-Cox staining were applied to assess the impact of the dopamine D2 receptor and PI3K pathway on synaptic morphology. Fluo-4-AM was used to clarify the role of the dopamine D2 receptor and PI3K signaling on neuronal calcium influx. The Src family kinase (SFK) inhibitor PP2 was used to explore the effect of Src kinase on GLUA1-containing AMPAR trafficking and the PI3K signaling pathway.

Results

Inflammatory soup stimulation significantly reduced pain thresholds in rats, accompanied by an increase in PI3K-P110β subunit expression, loss of dopamine receptor D2 expression, and enhanced GLUA1-containing AMPA receptor trafficking in the trigeminal nucleus caudalis (TNC). The dopamine D2 receptor colocalized with the GLUA1-containing AMPA receptor in the TNC; quinpirole, LY294002, and NASPM alleviated pain hypersensitivity and reduced GLUA1-containing AMPA receptor trafficking in chronic migraine rats. Sulpiride aggravated pain hypersensitivity and enhanced GLUA1 trafficking in CM rats. Importantly, the anti-injury and central sensitization-mitigating effects of quinpirole were reversed by 740YP. Both quinpirole and LY294002 inhibited calcium influx to neurons and modulated the synaptic morphology in the TNC. Additional results suggested that DRD2 may regulate PI3K signaling through Src family kinases.

Conclusion

Modulation of GLUA1-containing AMPA receptor trafficking and central sensitization by the dopamine D2 receptor via the PI3K signaling pathway may contribute to the pathogenesis of chronic migraine in rats, and the dopamine D2 receptor could be a valuable candidate for chronic migraine treatment.

Supplementary Information

The online version contains supplementary material available at 10.1186/s10194-022-01469-x.

Exploring the Anti-inflammatory Effects of Protopine Total Alkaloids of Macleaya Cordata (Willd.) R. Br

Macleaya cordata (Willd). R. Br. is a Chinese medicinal plant commonly used externally to treat inflammatory-related diseases such as arthritis, sores, and carbuncles. This study aimed to evaluate the anti-inflammatory activity of protopine total alkaloids (MPTAs) in Macleaya cordata (Willd.) R. Br. in vivo tests in rats with acute inflammation showed that MPTA (2.54 and 5.08 mg/kg) showed significant anti-inflammatory activity 6 h after carrageenan injection. Similarly, MPTA (3.67 and 7.33 mg/kg) showed significant anti-inflammatory activity in the mouse ear swelling test. In addition, the potential mechanisms of the anti-inflammatory effects of MPTA were explored based on network pharmacology and molecular docking. The two main active components of MPTA, protopine and allocryptopine, were identified, and the potential targets and signaling pathways of MPTA's anti-inflammatory effects were initially revealed using tools and databases (such as SwissTargetPrediction, GeneCards, and STRING) combined with molecular docking results. This study provides the basis for the application of MPTA as an anti-inflammatory agent.