The Effect Of Lentiviral Vector-mediated TNF-αSiRNA On Neurodegeneration In Niemann-Pick Type C Mice

Chronic inflammatory processes are considered to play an important role in theprogression of neurodegenerative diseases, such as Alzheimer's disease (AD), Parkinsondisease (PD), Amyotrophic lateral sclerosis (ALS) and Niemann-Pick disease type C (NPC),etc. It is thought that microglia activation and the TNF-αit relased participate andaccelerated the neuronal dysfunction, regulates synaptic mechanisms, and mediatesamyloidinduced disruption of molecular mechanisms involved in memory. Many studiesshowed that downregulation of TNF-αby its blockers and TNF-α-SiRNA resulted inpredominant improvement of the symptom of AD patients, ALS patients and theneuropathology of AD mouse model. It is not know whether TNF-αis essential key for theneurodegeneration. The naturally occurring npc-1 mutant mouse mimics human NPC, indiaplaying activation of mocroglia and over excess TNF-αbut its role in the neuropathologyand the processing of NPC is not clearly. We use this mouse model and lentiviral-deliveredTNF-α-SiRNA to determine whether TNF-αis necessary for NPC neuropathology. In thisstudy, we constructed Lentivector-mediated-TNF-α-SiRNA, and the tite was 2×10~8ifu/L.Interference efficiency of the lentivirus expressing TNF-α-SiRNA, was determined byRT-PCR and Elisa in BV-2 cells and astrocytes. At the same time, the constructedLenti-TNF-α-SiRNA was intracerebroventricularly infused into 4-week old npc mice for a4-week period. By using immunohistochemistry and real-time PCR, the down-regulation ofthe target genes was detected. We observed the neuropathology and the behavior of npc niceby immunohistology, western-blot, body weight, hanger test and foot print. As a result, theLenti-TNF-α-SiRNA downregulated the expression of murine TNF-αgene efficiently invitro and in vivo. Lentivirus could be expressed stably for long-term in the npc mice brainand reduced the hyperphosphorylation of cytoskeleton and improved the behavior of npcmice, which provided a potential tool for studying and treating neurodegenerative diseasesand TNF-α-related diseases.