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

The Role of Exosomes in Central Immune Tolerance and Myasthenia Gravis

BACKGROUND

Immune homeostasis plays a crucial role in immunology andis dependent on both central and peripheral tolerance. Centraltolerance and peripheral tolerance occur in the thymus and thesecondary lymphoid tissues, respectively. Tolerance breakdown andimmune regulation defects can lead to autoimmune disorders. In thisreview article, we aimed to describe the role of exosomes inregulating central tolerance and provide a summary of their effectson the pathogenesis, diagnosis, and therapeutic potential inmyasthenia gravis (MG).

METHODS

Articles for this review wereidentified using the PubMed database.

RESULTS

As the primarylymphoid organ, the thymus is responsible for building an immunecompetent, yet self-tolerant of T-cell population. Thymic statesinclude thymoma, thymic hyperplasia, and thymic atrophy, which canexert a significant influence on the central immune tolerance andrepresent specific characteristics of MG. Previous studies have foundthat exosomes derived from human thymic epithelial cells carryantigen-presenting molecules and a wide range of tissue restrictedantigens, which may indicate a vital role of thymic exosomes in MG.Besides, exosomal miRNAs and lncRNAs may also play a critical role inthe pathophysiology of MG.

CONCLUSION

This review provides thetherapeutic and diagnostic potential of exosomes in MG patients.

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.

Registered trials on novel therapies for myasthenia gravis: a cross-sectional study on ClinicalTrials.gov

Novel biologics in MG therapy research is on the rise. This research aimed to investigate the characteristics of registered trials on novel therapies for myasthenia gravis on ClinicalTrials.gov. This cross-sectional study used a descriptive approach to assess the features of the included trials on ClinicalTrials.gov. We found 62 registered trials from 2007 to 2023 on ClinicalTrials.gov. The results showed a yearly rise in the number of registered trials (r = 0.76, p < 0.001). Following 2017, more industry-sponsored trials were conducted (91.5% [43] vs. 60% [9], p = 0.009), fewer results were released (10.6% [5] vs. 60% [9], p = 0.001), and more trials entered phase 3 (67.4% [31] vs. 20% [2], p = 0.001). The most researched novel medications were neonatal Fc receptor inhibitors (51.2% [21]), complement inhibitors (39.0% [16]), and B cell depletors (14.6% [6]). According to the website's data, the neonatal Fc receptor inhibitors and complement inhibitors were effective in treating myasthenia gravis patients in three trials (NCT03315130, NCT03669588, and NCT00727194). This study provides valuable insights into the profile of registered trials on novel therapies for myasthenia gravis. More clinical studies are needed in the future to prove the value of its application.

Myasthenia Gravis Treatment: From Old Drugs to Innovative Therapies with a Glimpse into the Future

Myasthenia gravis (MG) is a rare autoimmune disease that causes debilitating muscle weakness due to impaired neuromuscular transmission. Since most (about 80-90%) MG patients present autoantibodies against the acetylcholine receptor, standard medical therapy consists of symptomatic treatment with acetylcholinesterase inhibitors (e.g., pyridostigmine). In addition, considering the autoimmune basis of MG, standard therapy includes immunomodulating agents, such as corticosteroids, azathioprine, cyclosporine A, and cyclophosphamide. New strategies have been proposed for the treatment of MG and include complement blockade (i.e., eculizumab, ravulizumab, and zilucoplan) and neonatal Fc receptor antagonism (i.e., efgartigimod and rozanolixizumab). The aim of this review is to provide a detailed overview of the pre- and post-marketing evidence on the five pharmacological treatments most recently approved for the treatment of MG, by identifying both preclinical and clinical studies registered in clinicaltrials.gov. A description of the molecules currently under evaluation for the treatment of MG is also provided.