Myocarditis is a progressive inflammatory disorder of the myocardium and a significant cause of sudden cardiac death and dilated cardiomyopathy (DCM), especially in young individuals. Although immunosuppressive or immunomodulatory therapies are currently employed for autoimmune or virus-negative myocarditis, their clinical application is often hampered by limited efficacy and systemic side effects. There is an urgent need for safer and more precisely targeted therapeutic options [1], [2], [3], [4], [5], [6].

Despite its diverse etiologies, a critical stage in myocarditis progression is the transition from acute inflammation to chronic fibrosis, which leads to cardiac dysfunction [1], [7], [8]. Emerging evidence highlights the pivotal role of T helper 17 (Th17) cells and their signature cytokine interleukin-17A (IL-17A) in driving cardiac inflammation and fibrosis in both experimental and human myocarditis [9], [10]. In parallel, transforming growth factor-β (TGF-β) acts as a master regulator of fibrosis, stimulating the activation and differentiation of CFs into myofibroblasts [11], [12], [13], [14]. These findings position CFs as central cellular hubs that integrate inflammatory and fibrotic signaling in myocarditis and suggest that simultaneous modulation of both axes in CFs may be particularly effective.

Neddylation is a post-translational modification in which the ubiquitin-like protein NEDD8 is covalently attached to specific substrates by NEDD8-specific E1, E2 and E3 enzymes, thereby regulating cullin-RING ligase activity, protein stability and multiple inflammatory and fibrotic signaling cascades [15], [16]. Studies in rheumatoid arthritis, liver and kidney fibrosis have shown that dysregulated neddylation promotes pro-inflammatory and profibrotic activation of tissue-resident mesenchymal cells, including fibroblast-like synoviocytes, hepatic stellate cells and renal interstitial fibroblasts [17], [18], [19]. In the cardiovascular system, neddylation is essential for perinatal cardiac maturation and the maintenance of cardiac function and its selective DCN1 inhibitors has shown promise in reducing pathological fibrosis and remodeling in experimental models [20], [21]. Specifically, systemic administration of the NEDD8-activating enzyme inhibitor MLN4924 was found to ameliorate experimental autoimmune myocarditis by modulating inflammatory signaling in cardiomyocytes [22]. Critically, the specific contribution of neddylation to CF activation during myocarditis and thus the potential of a fibroblast-targeted strategy to more effectively uncouple inflammation from fibrosis, remain undefined.

Therefore, the present study was designed to address these fundamental gaps. We first aimed to elucidate the role of neddylation in mediating the pathological activation of cardiac fibroblasts driven by IL-17A and TGF-β. Subsequently, to overcome the limitations of systemic administration, we developed a novel biomimetic nanoplatform. Building on the established biocompatibility of liposomes and leveraging the homologous targeting effect of cell membrane camouflage, we engineered a fibroblast-membrane-camouflaged liposomal system to deliver MLN4924 (FMlipo@MLN4924). Finally, we evaluated this targeted strategy in the EAM model, with the goal of enhancing therapeutic efficacy and elucidating the role of neddylation within this key pathogenic cell type.