In vitiligo, skin pigment cells lose color because a molecular brake on inflammation (the protein NLRP3) fails to be cleared from cells, leading to excessive cell death. Researchers found this happens because a key recycling enzyme is reduced in vitiligo melanocytes. Delivering Nlrp3-silencing genetic material using KPV-modified liposomes, where KPV acts as a targeting tag, significantly slowed vitiligo progression in mice and points toward a targeted cell-specific treatment approach.
Abstract
NLRP3 functions as a critical intracellular danger sensor for inflammasome activation, playing a crucial role in autoimmune diseases. Vitiligo progression has been linked to NLRP3, yet its specific involvement in melanocytes of vitiligo remains poorly understood. In this study, we demonstrate that NLRP3 expression is significantly upregulated in the melanocytes of vitiligo patients and melanoma-Treg-induced vitiligo mouse model. Genetic knockout of NLRP3 effectively alleviates vitiligo progression in these mice. Our mechanistic investigations reveal that the downregulation of the E3 ligase β-TrCP1 in vitiligo melanocytes decreases K27-linked ubiquitination levels of NLRP3, which in turn weakens its interaction with the autophagy receptor NDP52. This disruption impairs the selective autophagic degradation of NLRP3, leading to hyperactivation of inflammation and pyroptosis in melanocytes, thereby accelerating vitiligo pathogenesis. Notably, melanocyte-specific knockdown of NLRP3 using lysine-proline-valine (KPV)-modified deformable liposomes (KPV-Lipos) carrying Nlrp3 shRNA significantly alleviates vitiligo development. This study elucidates the mechanism by which autophagy dysfunction mediated excessive NLRP3 inflammasome activation in melanocytes contributes to vitiligo pathogenesis, highlighting potential therapeutic strategies targeting these pathways for the treatment of vitiligo and other pigment-related skin diseases. Overview of disrupted NLRP3 autophagic degradation in vitiligo melanocytes. In healthy melanocytes, NLRP3 expression is upregulated when subjected to oxidative stress, along with an increase in the E3 ligase β-TrCP1, which enhances the K27-linked ubiquitination of NLRP3 and further strengthens its binding to the autophagy receptor protein NDP52, thus effectively suppressing the excessive inflammatory response. Whereas in the melanocytes of vitiligo patients, decreased expression of β-TrCP1 leads to downregulation of K27-linked ubiquitination in NLRP3, thus inhibiting its autophagic degradation. The persistent activation of NLRP3 in vitiligo melanocytes promotes the cleavage of pro-IL-1β and GSDMD. GSDMD-N subsequently forms pores on the cell membrane, which causes the release of IL-1β and results in melanocyte pyroptosis. In our study, we utilize KPV-Lipos with Nlrp3 shRNA to precisely knockdown NLRP3 expression in melanocytes and effectively alleviate vitiligo development, which provide a potentially promising strategy for the treatment of vitiligo. MC, melanocytes.