Effect of Grilled Nux Vomica on Differential RNA Expression Profile of Gastrocnemius Muscle and Toll‑Like Receptor 4 (TLR-4)/Nuclear Factor kappa B (NF-κB) Signaling in Experimental Autoimmune Myasthenia Gravis Rats

Grilled nux vomica alleviates myasthenia gravis by inhibiting the JAK2/STAT3 signaling pathway: a study in a mice model

BACKGROUND

Grilled Nux Vomica (GNV) is a promising traditional Chinese medicine to treat myasthenia gravis (MG), but its effects and mechanisms need further exploration.

METHODS

Experimental autoimmune MG (EAMG) model was established by muscle-specific kinase (MuSK) induction on C57BL/6 J mice. Mice were treated with GNV and/or ruxolitinib (JAK2 inhibitor) or AG490 (STAT3 inhibitor) for 30 days via gavage after modeling and randomized into 7 groups: control, model, low-dose GNV, middle-dose GNV, high-dose GNV, GNV + ruxolitinib, GNV + AG490. Body weight, muscle strength, clinical score, MuSK level, neuromuscular junction integrity (agrin and acetylcholine receptor [AChR] levels), inflammatory factors (IL-2 and IL-6), and the activation of the JAK2/STAT3 pathway were measured and compared between groups.

RESULTS

GNV significantly improved body weight and muscle strength, as well as reduced clinical scores, MuSK levels, and inflammatory markers (IL-2 and IL-6) levels compared with untreated EAMG mice. GNV also protected the neuromuscular junction and increased agrin and AChR co-expression in a dose-dependent manner. In addition, GNV attenuated the levels of p-JAK2 and p-STAT3, which are aberrantly upregulated in EAMG mice. After co-treatment with ruxolitinib or AG490, the effect of GNV on body weight, muscle strength, clinical score, MuSK level, neuromuscular junction integrity, levels of inflammatory factors, and JAK2/STAT3 pathway was further amplified in EAMG mice.

CONCLUSIONS

GNV improves MG by inhibiting the JAK2/STAT3 pathway, which might be an effective therapeutic strategy for MG.

Myasthenia Gravis: Novel Findings and Perspectives on Traditional to Regenerative Therapeutic Interventions

The prevalence of myasthenia gravis (MG), an autoimmune disorder, is increasing among all subsets of the population leading to an elevated economic and social burden. The pathogenesis of MG is characterized by the synthesis of autoantibodies against the acetylcholine receptor (AChR), low-density lipoprotein receptor-related protein 4 (LRP4), or muscle-specific kinase at the neuromuscular junction, thereby leading to muscular weakness and fatigue. Based on clinical and laboratory examinations, the research is focused on distinguishing MG from other autoimmune, genetic diseases of neuromuscular transmission. Technological advancements in machine learning, a subset of artificial intelligence (AI) have been assistive in accurate diagnosis and management. Besides, addressing the clinical needs of MG patients is critical to improving quality of life (QoL) and satisfaction. Lifestyle changes including physical exercise and traditional Chinese medicine/herbs have also been shown to exert an ameliorative impact on MG progression. To achieve enhanced therapeutic efficacy, cholinesterase inhibitors, immunosuppressive drugs, and steroids in addition to plasma exchange therapy are widely recommended. Under surgical intervention, thymectomy is the only feasible alternative to removing thymoma to overcome thymoma-associated MG. Although these conventional and current therapeutic approaches are effective, the associated adverse events and surgical complexity limit their wide application. Moreover, Restivo et al. also, to increase survival and QoL, further recent developments revealed that antibody, gene, and regenerative therapies (such as stem cells and exosomes) are currently being investigated as a safer and more efficacious alternative. Considering these above-mentioned points, we have comprehensively reviewed the recent advances in pathological etiologies of MG including COVID-19, and its therapeutic management.

Prediction of prognosis, immune infiltration and immunotherapy response with N6-methyladenosine-related lncRNA clustering patterns in cervical cancer

LncRNAs and tumor microenvironment (TME) exert an important effect in antitumor immunity. Nonetheless, the role of m⁶A-related lncRNA clustering patterns in prognosis, TME and immunotherapy of cervical cancer (CC) remains unknown. Here, based on 7 m⁶A-related prognostic lncRNAs obtained from TCGA-CC dataset, two m⁶AlncRNA clustering patterns were determined. m⁶AlncRNA clusterA was characterized by immune cell infiltrates and immune activation. m⁶AlncRNA clusterB was characterized by enrichment of immune evasion and tumorigenic activation pathways as well as survival and clinical stage disadvantage. Then, principal component analysis algorithms were used to construct m⁶AlncRNAscore based on prognostic differentially expressed genes between two m⁶AlncRNA clusters to quantify m⁶AlncRNA clustering patterns. m⁶AlncRNAscore was an independent prognostic protective factor. Higher Th2 and Treg cells and enrichment of immunosuppressive pathways were observed in the low-m⁶AlncRNAscore group, with poorer survival. High-m⁶AlncRNAscore was characterized by increased infiltration of activated CD8 T cell, enrichment of immune activation pathways, lower IL-10 and TGF-beta1 levels, and higher immunophenscore values, indicating inflamed TME and better anti-tumor immunotherapy efficacy. Quantitative Real-Time Polymerase Chain Reaction was used for detection of m⁶A-related prognostic lncRNAs. Collectively, we identified two m⁶AlncRNA clustering patterns which play a nonnegligible role in the prognosis, TME heterogeneity and immunotherapy of CC patients.

Sorting nexin 17 increases low-density lipoprotein receptor-related protein 4 membrane expression: A novel mechanism of acetylcholine receptor aggregation in myasthenia gravis

Myasthenia gravis (MG) is characterized by autoimmune damage to the postsynaptic membrane of the neuromuscular junction (NMJ) with impaired postsynaptic acetylcholine receptor (AChR) aggregation. Low-density lipoprotein receptor-related protein 4 (LRP4) plays an important role in AChR aggregation at endplate membranes via the Agrin–LRP4–muscle-specific receptor tyrosine kinase (MuSK) cascade. Sorting nexin 17 (SNX17) regulates the degradation and recycling of various internalized membrane proteins. However, whether SNX17 regulates LRP4 remains unclear. Therefore, we examined the regulatory effects of SNX17 on LRP4 and its influence on AChR aggregation in MG. We selected C2C12 myotubes and induced LRP4 internalization via stimulation with anti-LRP4 antibody and confirmed intracellular interaction between SNX17 and LRP4. SNX17 knockdown and overexpression confirmed that SNX17 promoted MuSK phosphorylation and AChR aggregation by increasing cell surface LRP4 expression. By establishing experimental autoimmune MG (EAMG) mouse models, we identified that SNX17 upregulation improved fragmentation of the AChR structure at the NMJ and alleviated leg weakness in EAMG mice. Thus, these results reveal that SNX17 may be a novel target for future MG therapy.

Study on the Potential Mechanism of Semen Strychni against Myasthenia Gravis Based on Network Pharmacology and Molecular Docking with Experimental Verification

Background

Semen Strychni (SS) is an effective Chinese medicine formula for treating myasthenia gravis (MG) in clinics. Nonetheless, its molecular mechanism is largely unknown.

Objective

Using network pharmacology, molecular docking, and experimental validation, we aim to identify the therapeutic effect of SS on MG and its underlying mechanism.

Methods

The main ingredients of SS and their targets and potential disease targets for MG were extracted from public databases. The protein-protein interaction (PPI) network was constructed using the STRING 11.0 database, and Cytoscape was used to identify the hub targets. In addition, Gene Ontology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG) were used to identify molecular biological processes and signaling pathways. Then, AutoDock Via conducted molecular docking. The experimental autoimmune myasthenia gravis (EAMG) model in female Lewis rats, quantitative real-time polymerase chain reaction (qRT-PCR), Western blot, and enzyme-linked immunosorbent assay (ELISA) were performed to confirm the effect and mechanism of SS on MG.

Results

The following active compounds and hub targets were identified by screening and analyzing: isobrucine, vomicine, (S)-stylopine, strychnine, brucine-N-oxide, brucine and AKT1, MAPK1, MAPK14, CHRM1, ACHE, and CHRNA4. KEGG enrichment analyses indicated that the cholinergic synapse and neuroactive ligand-receptor interaction signaling pathway may be necessary. The results of molecular docking revealed that the main active ingredients bind well to the hub targets. In vivo experiments proved that SS could improve the weight loss and Lennon scores in the EAMG model. Experiments in molecular biology showed that SS could treat MG by affecting the cholinergic synapse through the respective antibody, receptor, and key enzymes in the cholinergic pathway.

Conclusion

This study provided a preliminary overview of the active constituents, primary targets, and potential pathways of SS against MG. SS ameliorated EAMG by regulating the cholinergic synaptic junction.

Systems Pharmacology and Molecular Docking Reveals the Mechanisms of Nux Vomica for the Prevention of Myasthenia Gravis

Background

Myasthenia gravis (MG) is a rare autoimmune disease with clinical symptoms of fluctuating muscle weakness. Due to the side effects of current therapies, there is an urgent need for a new medication for MG treatment. Nux vomica is a traditional Chinese medicine used in various diseases. However, the mechanism of action of Nux vomica against MG remains unclear.

Methods

Network pharmacology was used to explore the underlying mechanisms of Nux vomica in MG treatment, which was validated using molecular docking and in vivo experiments in mice.

Results

Twelve bioactive compounds and 72 targets in Nux vomica were screened. Seventy-nine myasthenia-related targets were obtained from the GENECARD and DisGeNET databases. PPI networks of Nux vomica- and myasthenia-related targets were constructed using Bisogenet, and these two networks were subsequently merged into an intersection to establish a core-target PPI network that consisted of 204 nodes and 4,668 edges. KEGG enrichment analysis indicated that 132 pathways were enriched in 204 core targets. In addition, we obtained 50 docking pairs via molecular docking. In vivo experiments revealed that Nux vomica can improve the symptoms of MG.

Conclusion

Nux vomica is involved in the pathogenesis of MG through the “multicomponent-target-pathway” mechanism.

miR-181a Ameliorates the Progression of Myasthenia Gravis by Regulating TRIM9

Abnormally activated CD4+ T cells are considered to be an important factor in the pathogenesis of myasthenia gravis (MG). In the pathogenesis of MG, the imbalance of proinflammatory cytokines and immune cells maintains the imbalance of immune response and inflammatory microenvironment. Studies have shown that miRNA is involved in the pathogenesis of MG. In our experiment, we extracted peripheral blood mononuclear cells (PBMCs) from MG patients and detected the expression of miR-181a and TRIM9 in PBMCs by qRT-PCR. In vitro experiments were conducted to explore the regulatory mechanism of miR-181a on target genes and its influence on inflammatory factors related to MG disease. Experimental autoimmune myasthenia gravis (EAMG) model mice are established, and the effects of miR-181a on EAMG symptoms and inflammatory factors are explored through in vivo experiments. According to a total of 40 EAMG mice that were successfully modeled, all EAMG mice showed symptoms of muscle weakness; their diet was reduced; their weight gain was slow; and even weight loss occurred. In MG patients and EAMG mice, the expression of miR-181a was low and TRIM9 was highly expressed. Bioinformatics website and dual-luciferase report analysis of miR-181a had a targeting relationship with TRIM9, and miR-181a could target the expression of TRIM9. After upregulating miR-181a or interfering with TRIM9, serum miR-181a in EAMG mice was significantly upregulated; TRIM9 was significantly downregulated; its clinical symptoms were reduced; and the expression of inflammatory factors was reduced. The study finally learned that miR-181a can reduce the level of MG inflammatory factors by targeting the expression of TRIM9 and has the effect of improving the symptoms of MG.

Qiangji Jianli Decoction promotes mitochondrial biogenesis in skeletal muscle of myasthenia gravis rats via AMPK/PGC-1α signaling pathway

The Qiangji Jianli Decoction (QJJLD) is an effective Chinese medicine formula for treating Myasthenia gravis (MG) in the clinic. QJJLD has been proven to regulate mitochondrial fusion and fission of skeletal muscle in myasthenia gravis. In this study, we investigated whether QJJLD plays a therapeutic role in regulating mitochondrial biogenesis in MG and explored the underlying mechanism. Rats were experimentally induced to establish autoimmune myasthenia gravis (EAMG) by subcutaneous immunization with R97-116 peptides. The treatment groups were administered three different dosages of QJJLD respectively. After the intervention of QJJLD, the pathological changes of gastrocnemius muscle in MG rats were significantly improved; SOD, GSH-Px, Na⁺-K⁺ ATPase and Ca²⁺-Mg²⁺ ATPase activities were increased; and MDA content was decreased in the gastrocnemius muscle. Moreover, AMPK, p38MAPK, PGC-1α, NRF-1, Tfam and COX IV mRNA and protein expression levels were also reversed by QJJLD. These results implied that QJJLD may provide a potential therapeutic strategy through promoting mitochondrial biogenesis to alleviate MG via activating the AMPK/PGC-1α signaling pathway.