Mitochondria-targeted TPP-MoS2 with dual enzyme activity provides efficient neuroprotection through M1/M2 microglial polarization in an Alzheimer's disease model

Alzheimer's disease (AD) is one of the most common age-associated brain diseases and is induced by the accumulation of amyloid beta (Aβ) and oxidative stress. Many studies have focused on eliminating Aβ by nanoparticle affinity; however, nanoparticles are taken up mainly by microglia rather than neurons, leading poor control of AD. Herein, mitochondria-targeted nanozymes known as (3-carboxypropyl)triphenyl-phosphonium bromide-conjugated 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[amino(polyethylene glycol)-2000]-functionalized molybdenum disulfide quantum dots (TPP-MoS2 QDs) were designed. TPP-MoS2 QDs mitigate Aβ aggregate-mediated neurotoxicity and eliminate Aβ aggregates in AD mice by switching microglia from the proinflammatory M1 phenotype to the anti-inflammatory M2 phenotype. TPP-MoS2 QDs cross the blood-brain barrier, escape from lysosomes, target mitochondria and exhibit the comprehensive activity of a bifunctional nanozyme, thus preventing spontaneous neuroinflammation by regulating the proinflammatory substances interleukin-1β, interleukin-6 and tumor necrosis factors as well as the anti-inflammatory substance transforming growth factor-β. In contrast to the low efficacy of eliminating Aβ by nanoparticle affinity, the present study provides a new pathway to mitigate AD pathology through mitochondria-targeted nanozymes and M1/M2 microglial polarization.