Enhancement of lysosome biogenesis as a potential therapeutic approach for neurodegenerative diseases

Millions of people are suffering from Alzheimer’s disease globally,but there is still no effective treatment for this neurodegenerative disease.Thus,novel therapeutic approaches for Alzheimer’s disease are needed,which requires further evaluation of the regulato ry mechanisms of protein aggregate degradation.Lysosomes are crucial degradative organelles that maintain cellular homeostasis.Transcription factor EB-mediated lysosome biogenesis enhances autolysosomedependent degradation,which subsequently alleviates neurodege nerative diseases,including Alzheimer’s disease,Parkinson’s disease,and Huntington’s disease.In this review,we start by describing the key features of lysosomes,including their roles in nutrient sensing and degradation,and their functional impairments in different neurodegenerative diseases.We also explain the mechanisms—especially the post-translational modifications—which impact transcription factor EB and regulate lysosome biogenesis.Next,we discuss strategies for promoting the degradation of toxic protein aggregates.We describe Proteolysis-Ta rgeting Chimera and related technologies for the targeted degradation of specific proteins.We also introduce a group of LYsosome-Enhancing Compounds,which promote transcription factor EB-mediated lysosome biogenesis and improve learning,memory,and cognitive function in APP-PSEN1 mice.In summary,this review highlights the key aspects of lysosome biology,the mechanisms of transcription factor EB activation and lysosome biogenesis,and the promising strategies which are emerging to alleviate the pathogenesis of neurodegenerative diseases.

Atg5 regulates late endosome and lysosome biogenesis

Autophagy is an evolutionarily conserved lysosome-based degradation process.Atg5 plays a very important role in autophagosome formation.Here we show that Atg5 is required for biogenesis of late endosomes and lysosomes in an autophagy-independent manner.In Atg5 cells,but not in other essential autophagy genes defecting cells,recycling and retrieval of late endosomal components from hybrid organelles are impaired,causing persistent hybrid organelles and defective formation of late endosomes and lysosomes.Defective retrieval of late endosomal components from hybrid organelles resulting from impaired recruitment of a component of V1-ATPase to acidic organelles blocks the pH-dependent retrieval of late endosomal components from hybrid organelles.Lowering the intracellular pH restores late endosome/lysosome biogenesis in Atg5 cells.Our data demonstrate an unexpected role of Atg5 and shed new light on late endosome and lysosome biogenesis.

A NOVEL DIRECT ACTIVATOR OF TFEB PROMOTES AUTOPHAGY AND LYSOSOME BIOGENESIS AND PROTECTS NEURONS IN THE BRAIN

Autophagy dysfunction is a common feature in neurodegenerative disorders caused by the accumulation of toxic,aggregate-prone proteins.Increasing evidence have demonstrated that genetic or pharmacological activation of transcription factor EB(TFEB),a master regulator of autophagy and lysosomal biogenesis,ameliorates neurotoxicity and rescues neurodegenerative phenotypes in several animal models of neurodegenerative diseases.

Jatrophane Diterpenoids from the Seeds of Euphorbia peplus with Potential Bioactivities in Lysosomal-Autophagy Pathway

Euphopepluanones F−K(1−4),four new jatrophane type diterpenoids were isolated from the seeds of Euphorbia peplus,along with eight known diterpenoids(5−12).Their structures were established on the basis of extensive spectroscopic analysis and X-ray crystallographic experiments.The new compounds 1−4 were assessed for their activities to induce lysosomal biogenesis through LysoTracker Red staining.Compound 2 significantly induced lysosomal biogenesis.In addi-tion,compound 2 could increase the number of LC3 dots,indicating that it could activate the lysosomal-autophagy pathway.

Celastrol enhances transcription factor EB (TFEB)-mediated autophagy and mitigates Tau pathology:Implications for Alzheimer's disease therapy

Alzheimer's disease(AD),characterized by the accumulation of protein aggregates including phosphorylated Tau aggregates,is the most common neurodegenerative disorder with limited therapeutic agents.Autophagy plays a critical role in the degradation of phosphorylated Tau aggregates,and transcription factor EB(TFEB)is a master regulator of autophagy and lysosomal biogenesis.Thus,small-molecule autophagy enhancers targeting TFEB hold promise for AD therapy.Here,we found that celastrol,an active ingredient isolated from the root extracts of Tripterygium wilfordii(Lei Gong Teng in Chinese)enhanced TFEB-mediated autophagy and lysosomal biogenesis in vitro and in mouse brains.Importantly,celastrol reduced phosphorylated Tau aggregates and attenuated memory dysfunction and cognitive deficits in P301S Tau and 3xTg mice,two commonly used AD animal models.Mechanistical studies suggest that TFEB-mediated autophagy-lysosomal pathway is responsible for phosphorylated Tau degradation in response to celastrol.Overall,our findings indicate that Celastrol is a novel TFEB activator that promotes the degradation of phosphorylated Tau aggregates and improves memory in AD animal models.Therefore,Celastrol shows potential as a novel agent for the treatment and/or prevention of AD and other tauopathies.