The experimental gene therapy with lentiviralmediated RNA interference targeting tumor necrosis factor-α

Abstract

Objective To investigate the effects of lentiviral-mediated RNA interference(RNAi) targeting tumor necrosis factor-α (TNF)-α gene on the expression of TNF-α, interleukin (IL)-1β, IL-6 of murine macrophages RAW264.7, and the efficiency of RNAi experimental gene therapy for the murine collagen-induced arthritis (CIA). Methods The RAW264.7 macrophages were infected by lentivirus-RNAi particles, then stimulated by Lipopolysaccharides(LPS). The TNF- α, IL-1β, IL-6 expression of RAW264.7 macrophages were measured with realtime polymerase chain reaction (PCR) and enzyme linked immunosorbent assay (ELISA). CIA models were esta-blished in DBA/1 mice using bovine type Ⅱ collagen. The treatment effect of lentivirus-RNAi on CIA were observed through arthritis scores, serum TNF-α measurement and hind paw paraffin section hematoxylin/eosin staining after lentivirus-RNAi particles tail vein injection. Results The TNF - α mRNA relative expression level of lentiviral RNAi group was 0.291±0.021, significantly lower than that of negative control group 0.925±0.013 (t=25.4, P<0.01). The inhibition rate in mRNA levels was 68.5%. The serum TNF-α level of lentiviral RNAi group was [(249±11) ng/ml], significantly lower than that of negative control [(382±6) ng/ml] (t=10.31, P<0.05). The inhibition rate of protein levels was 34.7%. It had no effect on the IL-1β and IL-6 mRNA expression. On the 8th day after systemic administration, the arthritis score of lentivirus-RNAi group was 2.50±0.19, which was significantly lower than that of blank controls (3.63±0.18) and negative controls (3.75± 0.16) (F=42.8, P<0.01). From now on, arthritis score of lentivirus-RNAi group and positive control decreased slowly to at least 2 weeks after treatment induction. The serum TNF- α levels of lentivirus-RNAi group and positive controls were [(35±6) pg/ml] and [(32±7) pg/ml] significantly lower than that of negative controls [(47±3) pg/ml] (t=3.03, 4.11, P<0.01) respectively. Morphological examination showed that the lentivirus-RNAi decreased CIA pathological manifestations. Conclusion Lentiviralmediated RNAi targeting murine TNF- α gene can effectively inhibit TNF- α expression both in vitro and in vivo, which also effectively improve the CIA arthritis score. Lentiviralmediated RNAi targeting TNF- α gene provides a potential strategy for rheumatoid arthritis (RA) treatment. Key words: Lentivirus; Tumor necrosis factor-α; RNA interference; Gene therapy, experimental