Alzheimer’s disease is a debilitating,progressive neurodegenerative disorder characterized by the progressive accumulation of abnormal proteins,including amyloid plaques and intracellular tau tangles,primarily within the brain.Lysosomes,crucial intracellular organelles responsible for protein degradation,play a key role in maintaining cellular homeostasis.Some studies have suggested a link between the dysregulation of the lysosomal system and pathogenesis of neurodegenerative diseases,including Alzheimer’s disease.Restoring the normal physiological function of lysosomes hold the potential to reduce the pathological burden and improve the symptoms of Alzheimer’s disease.Currently,the efficacy of drugs in treating Alzheimer’s disease is limited,with major challenges in drug delivery efficiency and targeting.Recently,nanomaterials have gained widespread use in Alzheimer’s disease drug research owing to their favorable physical and chemical properties.This review aims to provide a comprehensive overview of recent advances in using nanomaterials(polymeric nanomaterials,nanoemulsions,and carbon-based nanomaterials)to enhance lysosomal function in treating Alzheimer’s disease.This review also explores new concepts and potential therapeutic strategies for Alzheimer’s disease through the integration of nanomaterials and modulation of lysosomal function.In conclusion,this review emphasizes the potential of nanomaterials in modulating lysosomal function to improve the pathological features of Alzheimer’s disease.The application of nanotechnology to the development of Alzheimer’s disease drugs brings new ideas and approaches for future treatment of this disease.
Recent studies have suggested that abnormal acidification of lysosomes induces autophagic accumulation of amyloid-βin neurons,which is a key step in senile plaque formation.Therefore,resto ring normal lysosomal function and rebalancing lysosomal acidification in neurons in the brain may be a new treatment strategy for Alzheimer's disease.Microtubule acetylation/deacetylation plays a central role in lysosomal acidification.Here,we show that inhibiting the classic microtubule deacetylase histone deacetylase 6 with an histone deacetylase 6 shRNA or thehistone deacetylase 6 inhibitor valproic acid promoted lysosomal reacidification by modulating V-ATPase assembly in Alzheimer's disease.Fu rthermore,we found that treatment with valproic acid markedly enhanced autophagy.promoted clearance of amyloid-βaggregates,and ameliorated cognitive deficits in a mouse model of Alzheimer's disease.Our findings demonstrate a previously unknown neuroprotective mechanism in Alzheimer's disease,in which histone deacetylase 6 inhibition by valproic acid increases V-ATPase assembly and lysosomal acidification.
Zhimin LongChuanhua GeYueyang ZhaoYuanjie LiuQinghua ZengQing TangZhifang DongGuiqiong He
Calcification of cartilage by hydroxyapatite is a hallmark of osteoarthritis and its deposition strongly correlates with the severity of osteoarthritis.However,no effective strategies are available to date on the prevention of hydroxyapatite deposition within the osteoarthritic cartilage and its role in the pathogenesis of this degenerative condition is still controversial.Therefore,the present work aims at uncovering the pathogenic mechanism of intra-cartilaginous hydroxyapatite in osteoarthritis and developing feasible strategies to counter its detrimental effects.With the use of in vitro and in vivo models of osteoarthritis,hydroxyapatite crystallites deposited in the cartilage are found to be phagocytized by resident chondrocytes and processed by the lysosomes of those cells.This results in lysosomal membrane permeabilization(LMP)and release of cathepsin B(CTSB)into the cytosol.The cytosolic CTSB,in turn,activates NOD-like receptor protein-3(NLRP3)inflammasomes and subsequently instigates chondrocyte pyroptosis.Inhibition of LMP and CTSB in vivo are effective in managing the progression of osteoarthritis.The present work provides a conceptual therapeutic solution for the prevention of osteoarthritis via alleviation of lysosomal destabilization.
Lysosomes are discrete organelles that act as recycling centers for extracellular and intracellular materials,playing a pivotal role in maintaining cellular homeostasis.Their acidic environment,maintained by numerous hydrolytic enzymes,facilitates substrate degradation.Dysfunction in lysosomal processes can lead to abnormal substrate degradation,significantly impacting cellular homeostasis.High energy-demanding cells,such as post-mitotic neurons,are especially vulnerable to these changes,often resulting in neurological diseases.Autophagy,a conserved catabolic process,requires extensive lysosomal utilization.It plays a key role in removing unnecessary intracellular components,ensuring cellular homeostasis,and promoting cell survival during stress conditions such as starvation,infection,or cellular damage.
Benzo[4,5]imidazo[1,2-a]pyrimidine-based derivatives play crucial roles in medicines,pesticides,tracers and photoelectric materials.However,their synthesis approach still needs to be optimized,and their fluorescent properties in intracellular microenvironment are unclear.Here,a Cu(II)-catalyzed cascade coupling cyclization reaction was successfully developed to synthesize benzo[4,5]imidazo[1,2-a]pyrimidine scaffold with mild reaction conditions,broad substrate scopes and high yields.After a system study,we found that compound 4aa displayed an optimal viscosity-specific response with remarkable fluorescence enhancement(102-fold)for glycerol at 490 nm.Particularly,4aa possessed excellent structure-inherent targeting(SIT)capability for lysosome(P=0.95)with high p H stability and large Stokes shift.Importantly,4aa was validated for its effectiveness in diagnosing lysosomal storage disorders(LSD)in living cells.The 4aa also showed its potential to map the micro-viscosity and its metabolism process in zebrafish.This work not only affords an efficient protocol to fabricate benzo[4,5]imidazo[1,2-a]pyrimidine derivatives,reveals this skeleton has excellent SIT features for lysosome,but also manifests that 4aa can serve as a practical tool to monitor lysosomal viscosity and diagnose LSD.
Nanocarriers have therapeutic potential to facilitate drug delivery,including biological agents,smallmolecule drugs,and nucleic acids.However,their efficiency is limited by several factors;among which,endosomal/lysosomal degradation after endocytosis is the most important.This review summarizes advanced strategies for overcoming endosomal/lysosomal barriers to efficient nanodrug delivery based on the perspective of cellular uptake and intracellular transport mechanisms.These strategies include promoting endosomal/lysosomal escape,using non-endocytic methods of delivery to directly cross the cell membrane to evade endosomes/lysosomes and making a detour pathway to evade endosomes/lysosomes.On the basis of the findings of this review,we proposed several promising strategies for overcoming endosomal/lysosomal barriers through the smarter and more efficient design of nanodrug delivery systems for future clinical applications.
Hernandezine(Her),a bisbenzylisoquinoline alkaloid extracted from Thalictrum flavum,is recognized for its range of biological activities inherent to this herbal medicine.Despite its notable properties,the anti-cancer effects of Her have remained largely unexplored.In this study,we elucidated that Her significantly induced cytotoxicity in cancer cells through the activation of apoptosis and necroptosis mechanisms.Furthermore,Her triggered autophagosome formation by activating the AMPK and ATG5 conjugation systems,leading to LC3 lipidation.Our findings revealed that Her caused damage to the mitochondrial membrane,with the damaged mitochondria undergoing mitophagy,as evidenced by the elevated expression of mitophagy markers.Conversely,Her disrupted autophagic flux,demonstrated by the upregulation of p62 and accumulation of autolysosomes,as observed in the RFP-GFP-LC3 reporter assay.Initially,we determined that Her did not prevent the fusion of autophagosomes and lysosomes.However,it inhibited the maturation of cathepsin D and increased lysosomal pH,indicating an impairment of lysosomal function.The use of the early-stage autophagy inhibitor,3-methyladenine(3-MA),did not suppress LC3II,suggesting that Her also induces noncanonical autophagy in autophagosome formation.The application of Bafilomycin A1,an inhibitor of noncanonical autophagy,diminished the recruitment of ATG16L1 and the accumulation of LC3II by Her,thereby augmenting Her-induced cell death.These observations imply that while autophagy initially plays a protective role,the disruption of the autophagic process by Her promotes programmed cell death.This study provides the first evidence of Her’s dual role in inducing apoptosis and necroptosis while also initiating and subsequently impairing autophagy to promote apoptotic cell death.These insights contribute to a deeper understanding of the mechanisms underlying programmed cell death,offering potential avenues for enhancing cancer prevention and therapeutic strategies.