Targeting TNFα Ameliorated Cationic PAMAM Dendrimer-Induced Hepatotoxicity via Regulating NLRP3 Inflammasomes Pathway

Hepatotoxicity of cationic poly amidoamine (PAMAM) dendrimers is one of the most urgent challenges to their medicinal application. Recent studies have indicated that proinflammatory cytokines were critical in nanomaterials-induced toxicity. However, little is known about the roles and underlying regulatory mechanisms of proinflammatory cytokines in cationic PAMAM dendrimer-induced hepatotoxicity. Thus, the aim of the current study was to explore the role of proinflammatory cytokine tumor necrosis factor alpha (TNFα) in cationic PAMAM dendrimer-induced liver injury and its underlying mechanism and develop novel strategies to reduce hepatotoxicity of cationic PAMAM dendrimers through regulating TNFα. In this study, we verified the significant overexpression of TNFα in cationic PAMAM dendrimer-induced hepatotoxicity in mice and found that targeting TNFα by etanercept could protect against cationic PAMAM dendrimer-induced liver injury. Interestingly, etanercept suppressed cationic PAMAM dendrimer-induced inflammasome signaling as demonstrated by reduced activation of NALP3, cleavage of Caspase-1, and maturation of interleukin (IL)-1β. Moreover, suppression of NLRP3 inflammasomes by belnacasan could also protect against cationic PAMAM dendrimer-induced hepatotoxicity and TNFα-induced acute hepatotoxicity. Notably, targeting either TNFα or inflammasomes reduced autophagy activation in hepatotoxicity triggered by cationic PAMAM dendrimers. In general, these findings revealed that targeting TNFα could ameliorate cationic PAMAM dendrimer-induced hepatotoxicity via regulating NLRP3 inflammasome pathway, underscoring that TNFα antagonism by etanercept could be used as an effective pharmacological approach to control hepatotoxicity of cationic PAMAM dendrimers and thus providing novel therapeutic strategies for managing liver toxicity of nanomaterials via regulating inflammatory mediators.