Researchers found that people with myasthenia gravis (an autoimmune disease) have lower levels of the hormone kisspeptin, and giving a kisspeptin-like peptide (KP10) to rats with a similar disease improved their symptoms by balancing immune cells and blocking a harmful inflammation pathway.

Myasthenia gravis (MG) is an autoimmune disorder affecting neuromuscular junctions. While neuroendocrine-immune system dysfunction plays a crucial role in the development of autoimmune diseases, its involvement in MG remains largely unexplored. Kisspeptin, a neuropeptide hormone and endogenous ligand for GPR54 receptor, has been demonstrated to regulate antitumor immunity, antiviral immunity, and several autoimmune diseases. However, the role and mechanism of kisspeptin in MG remain to be elucidated. Serum kisspeptin levels were measured by ELISA in MG patients and experimental autoimmune myasthenia gravis (EAMG) rats. EAMG rats were treated with KP10 (kisspeptin analog) to evaluate its effects on body weight, clinical scores, grip strength, antibody levels, and complement deposition. Hypothalamic Kiss1 expression was assessed using Western blot and immunofluorescence. Stereotactic injection of adeno-associated virus overexpressing Kiss1 was performed to study its regulatory effects on disease progression. CD4⁺ T cell transfer via tail vein, Western blot, and flow cytometry were employed to investigate KP10's modulatory effects on CD4⁺ T cell subsets and the NF-κB signaling pathway. Kisspeptin expression was significantly decreased in both MG patient sera and EAMG rat sera, with reduced hypothalamic Kiss1 expression in EAMG rats. Either hypothalamic Kiss1 overexpression or intraperitoneal KP10 administration significantly improved clinical signs in EAMG rats. Further in vivo and in vitro studies revealed that KP10 ameliorated EAMG clinical signs by modulating Th1/Th17/Treg cell balance through inhibition of NF-κB signaling pathway activation in CD4⁺ T cells. This study elucidates that Kisspeptin secreted by hypothalamic participates in MG pathogenesis through the Kisspeptin-GPR54-NF-κB signaling axis by regulating CD4⁺ T cell subset balance, suggesting that the kisspeptin/GPR54 pathway may serve as a potential therapeutic target for MG treatment.