RNA干扰小鼠NgR基因表达促进脊髓损伤修复的实验研究
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摘要
中枢神经系统(CNS)损伤后轴突难以再生的原因之一是轴突再生抑制性因子的存在, Nogo–A, MAG和Omgp通过一个共同的受体(NgR)发挥神经抑制作用, NgR是轴突再生抑制因子作用的集中点。
     本实验采用RNA干涉技术使NgR基因沉默,阻断抑制因子的传导通路,促进中枢神经轴突再生。应用RT-PCR﹑Western-Blot和免疫组织化学检测海马细胞内源性NgR基因沉默效果;体内实验表明,通过载体介导的特异性NgR干涉小发夹能够抑制NgR在脊髓神经元中的表达,同时脊髓损伤轴突再生特异性蛋白GAP-43的表达上调。
     实验证明,质粒介导的RNA干涉小发夹能够有效地沉默NgR基因,抑制NgR在脊髓神经元中的表达可以促进脊髓损伤的轴突再生。
Background
     Spinal cord injury (SCI) is a major problem in orthopaedics and neurodurgery. Until now, no breakthrough has been made. However, with the rapid development of modern science and technology and preclinical medicine especially the molecular biology, a series of experiments have been conducted concerning spinal cord regeneration, and invigorating results have been obtained. Currently, many methods are applied in the study of the SCI regeneration, including neurotrophic factors, antagonists for growth inhibitory factors, electrostimulation, neural transplantation involved peripheral nerve, embryonic spinal cord, neural stem cell, olfactory ensheathing cell and gene therapy, which could make recoveries of SCI of adult mammal to some extent.
     The regeneration of central nervous system (CNS) injury is always a hot spot as well as a difficulty of neuroscience. More and more researchers are focusing their eyes on the studies of SCI. At present, the inability of CNS neurons to regenerate and the growth-inhibitory molecules present in local environment are regarded as the main reasons for the failure of axon regeneration. And myelin and keloid-related inhibitory molecules may take a major role. So far, three major inhibitors from central nervous myelin sheath have been identified as Nogo-A, myelin-associated glycoprotein (MAG) and oligodendrocyte myelin glycoprotein (OMgp). These inhibitors are generated from oligodendrocytes and some neuron and could be found in the central and peripheral myelin sheath and on the surface of oligodendrocytes. These myelin proteins could induce growth cone collapse and inhibit axon outgrowth. Recent findings indicate that they inhibit axon growth by binding a common receptor, the Nogo-66 receptor (NgR).
     Mouse NgR is a protein of 473 amino acids, containing a transposition signal sequence and eight adjacent leucine-rich repeats (LRR) at its N terminal and a specific C-terminal unit. LRR domain shares a moderate amino acid homology (35%) with other proteins containing the same domain. The results from enzyme digest of NgR on the membrance have revealed that its C-terminal is an incidental component for signal of glycosylphosphatidy- linositol (GPI), which is similar to the GPI-anchored receptors. In Genebank, no obvious comparability has been observed between the total cDNA and NgR, except that only few expressed sequence tags (EST) could match some fragments of NgR sequence accurately. Rat NgRcDNA shares an amino acid homology of 89% with human NgRcDNA. In situ hybridization has proved the wide distribution of NgRcDNA in various kinds of SCI neurons, including cerebral cortex neurons, hippocampi neurons, cerebellum Purkinje cells and pons neurons. The distribution of NgR is consistent with that of its mRNA. NgR is expressed in CNS neurons but not in oligodendrocytes. However, Nogo could be expressed in oligodendrocytes, which illustrates that Nogo-A exerts inhibitory effect on central nerve just by interacting with the receptor NgR.
     RNA interference (RNAi) is a process of posttransc- riptional gene silencing by sequence-specific mRNA degradation, which is triggered by short double-stranded RNA. The main mechanism is that the dsRNAs get processed into small fragments of 21-23 nt by an RNase, which could be used as templates to cleave and destroy the cognate RNA at specific sites and with specific distance.
     Small interfering RNA (siRNA) is an extremely effective tool for reducing gene expression of target genes in a variety of organisms and cell types (e.g., worms, fruit flies, plants, and mammalian). The ability of transfected siRNAs to suppress the transcription of specific genes has proved a useful technique to probe gene function, gene knockout, antiviral research, and gene therapy in mammalian cells. This simple, effective and specific method for down-regulating gene expression holds enormous scientific, commercial, and therapeutic potential.
     Herein, we used small vector-mediated hairpin RNA (shRNA) to mediate NgR gene silencing in rat neurons. The shRNA could down-regulate NgR gene expression, blocking its interactions with myelin-related inhibitors (like Nogo-A, MAG, and OMgp), and therefore, promoting the axonal growth and the recovery of injured spinal cord. The results may provide a new strategy for systematic investigations on the therapy of SCI.
     Objective:
     1. 1.Design and synthesize small hairpin RNAs homologous to NgR and construct siNgR expression vector.
     2. 2.Transfect the constructed siNgR expression vector into mice hippocampal cells cultured in vitro to interfere with NgR expression in hippocampus, and screen out the shRNA with the highest inhibitory effect.
     3. Discuss the influences of interference of NgR gene on axon regeneration after SCI.
     Methods:
     1. Two NgR-specific siRNAs were chemically synthesized and the vector pMU6shRNA-NgR was constructed. The construction was verified for further experiments.
     2. Mice hippocampal cells were cultured in vitro. Then, the specific vector-mediated siRNA was transfected singly into hippocampal cells with liposomal transfection reagent. RT-PCR, Western-Blot, and immunohistochemical analysis were carried out to detect the silencing of endogenous NgR gene. The pMU6shRNA-NgR with the highest inhibition effect was screened out for the following experiments.
     3. Established a contusion model of SCI, which resulted in mice with incomplete paraplegia.
     4. Vectors incuding NgR-specific siRNAs were locally injected into zones of SCI. The expression of NgR mRNA was detected using RT-PCR and the presence of NgR protein was tested using Western-Blot.
     5. Detect the expression of GAP-43 protein using immunocytochemistry and predict the axon regeneration after NgR gene silencing.
     Results:
     1. The expression vector for NgR siRNA pMU6sh-NgR has been successfully constructed.
     2. NgR siRNAs have been proved to inhibit the expression of NgR in mice hippocampal cells. The expression of endogenous NgR mRNA has been down-regulated 57%and NgR protein has been down-regulated 52%with statistical significance (P<0.05).
     3. .In the mice model of SCI, the expression of CAP-43, a specific protein related to the neurite outgrowth after SCI, was found to increase after the injection of NgR siRNAs with statistical significance (P<0.05).
     Conclusions:
     We have demonstrated that chemically-synthesized NgR-specific siRNAs can effectively inhibit NgR expression in cultured mice hippocampal cells. NgR gene silencing is efficient and specific, and the effect is the most effective at 3 days post transfection. In mice SCI model, the level of NgR mRNA and protein was down-regulated significantly by the two siNgR. The increasing expression of GAP-43 mRNA could promote axon regeneration of mice after SCI.
     To sum up, our future work is to investigate NgR signal conduction pathway and other associated genes by multiple gene combination RNAi strategy. We hope to develop gene therapy medicine that could inhibit NgR, proliferation specifically and effectively.
引文
[l]Spinal cord regeneration[J]. Science,1996,273-451.
    [2]Cajal SRY.Degeneration and regeneration of the neuronal system [M].London ,Oxford University press,1928,3
    [3]DavidS,Aguayo AJ .Axonal elongation into peripheral neryous system “bridges”after central nervous system injury inadult rats [J].Science,1981,214:931-933
    [4]Koda M, Hashimoto M, Murakami M, et al. Adenovirus vector-mediated in vivo gene transfer of brain-derived neurotrophic factor (BDNF) promotes rubrospinal axonal regeneration and functional re- covery after complete transection of the adult rat spinal cord[J]. JNeurotrauma,2004, 21(3): 329-337.
    [5]Tuszynski MH, Grill R, Jones LL, et al. NT-3 gene delivery elicitsgrowth of chronically injured corticospinal axons and modestly im-proves functional deficits after chronic scar resection[J]. Exp Neu-rol,2003, 181(1): 47-56.
    [6]Cao L, Liu L, Chen ZY, et al. Olfactory ensheathing cells genetica-lly modified to secrete GDNF to promote spinal cord repair [J].Brain, 2004, 127(pt3): 535-549.
    [7]Grill R,Murai K,Blesch A,Gage FH,Tuszynski MH.1997.Cellular delivery of neurotrophin-3 promotes corticospinal axonal growth and partial functional recovery after spinal cord injury. J. Neurosci.17: 5560-72
    [8]SchnellL,Schneider R,Kolbeck R,BardeYA,Schwab ME.1994. Neurotr- ophin- 3 enhances sprouting of corticospinal tract duringdevelopment and after adult spinal cord lesion. Nature 367:170-73.
    [9]Bregman BS,McAtee M,Dai HN, Kuhn PL .1997. Neurotrophic factor-increase axonal growth after spinal cord injury and transplantation in the adult rat.Exp.Neurol.148:475-94.
    [10]Ghosh A,David S.1997.Neurite growth inhibitory activity in the adult rat cerebral cortical gray matter.J.Neurobiol.32:671-83.
    [11]Felderhoff-Mueser U, Sifringer M, Pesditschek S, et al.Pathwaysleading to apoptotic neurodegeneration following trauma to the de-veloping rat brain[J]. Neurobiol Dis, 2002, 11(2): 231-245.
    [12]Schwartz ED, Shumsky JS, Wehrli S, et al. Ex vivo MR determined apparent diffusion coefficients correlate with motor recovery media-ted by intraspinal transplants of fibroblasts genetically modified toexpress BDNF[J].Exp Neurol, 2003,182(1):49-63.
    [13] Hiebert GW, Khodarahmi K, McGraw J, et al. Brain-derived neu-rotrophic factor applied to the motor cortex promotes sprouting of corticospinal fibers but not regeneration into a peripheral nerve transplant[J]. Neurosci Res, 2002,69(2):160-168.
    [14]Taylor SJ, McDonald JW 3rd, Sakiyama-Elbert SE. Controlled re-lease of neurotrophin-3 from fibrin gels for spinal cord injury[J]. JControl Release, 2004, 98(2): 281-294.
    [15]Saini HS, Gorse KM, Boxer LM, et al. Neurotrophin-3 and a CREB-mediated signaling pathway regulate Bcl-2 expression in oligo- dendrocyte progenitor cells[J]. J Neurochem, 2004, 89(4): 951-961.
    [16]Jean I, Lavialle C, Barthelaix-Pouplard A, et al. Neurotrophin-3 specifically increases mature oligodendrocyte population and en-hances remyelination after chemical demyelination of adult rat CNS [J]. Brain Res, 2003, 972(1-2): 110-118.
    [17]Zhou L, Baumgartner BJ, Hill-Felberg SJ, et al. Neurotrophin-expressed in si tu induces axonal plasticity in the adult injured spinal cord [J]. Neurosci, 2003, 23 (4): 1424-1431.
    [18]Keir SD,Xiao X, Li J, et al. Adeno-associated virus-mediated de-livery of glial cell line-derived neurotrophic factor protects motor neuron-like cells from apoptosis[J].J Neurovirol, 2001 , 7 (5) : 437-446.
    [19]Zheng WH, Kar S, Quirion R. Insulin-like growth factor-1-in-duced phosphorylation of transcription factor FKHRL1 is mediated by phosphatidylinositol 3-kinase/Akt kinase and role of this pathway in insulin-like growth factor-1-induced survival of cultured hippocampal neurons[J].Mol Phammacol, 2002, 62(2): 225-233.
    [20]D'Ercole AJ, Ye P, O'Kusky JR. Mutant mouse models of insulin-like growth factor actions in the central nervous system[J].Neu-ropeptides, 2002, 36(2-3): 209-220.
    [21]Dow JK, deVere White RW. Fibroblast growth factor: its struc-ture and property, paracrine function, tumor angiogenesis, and prostate-related mitogenic and, oncogenic functions[J]. Urology, 2000, 55(6): 800-806.
    [22]Lu P, Jones LL, Tuszynski MH.BDNF-expressing marrow stroma cells support extensive axonal growth at sites of spinal cord injury [J].Exp Neurol,2005,191(2):344-360.
    [23]Arthur B, Mary JR,Lynne CW. NGF message and protein distribu-tion in the injured rat spinal cord[J].Exp Neurol, 2004, 188(1):115-127.
    [24]Qiao L, Vizzard MA. Up-regulation of tyrosine kinase (Trka,Trkb) receptor expression and phosphorylation in lumbosacral dorsal root ganglia after chronic spinal cord (T8-T10) injury[J]. Comp Neurol,2002,449(3):217-230.
    [25]Cao X, Tang C, Luo Y. Effect of nerve growth factor on neuronal apoptosis after spinal cord injury in rats[J]. Neurotrauma, 2002,5 (22):131-135.
    [26]Kim DH, Jahng TA. Continuous brain-derived neurotrophic factor (BDNF) infusion after methylprednisolone treatment in severe spinal cord injury[J]. Korean Med Sci,2004,19(1):113-122.
    [27]Novikova LN, Kellerth JO. Differential effects of neurotrophins onneuronal survival and axonal regeneration after spinal cord injury inadult rats[J]. Comp Neurol, 2002, 452(3):255-263.
    [28]Tuszynski MH, Peterson PA, Ray J,et al. Fibroblasts geneti-cally modified to produce nerve growth factor induce robust neuritic in growth after graftingto the spinal cord[J]. Exp Neurol, 1994,126:1-14.
    [29]Okano H,Momma S,Blaise D,et al. Transplantation of in vitro ex-panded neural stem cells results in neurogenesis and recovery of mo-tor function after spinal cord contusion injury in rats[J]. Soc Neu-rosci,2000,26(4):863.
    [30]Galvin KA,Jones DG. Adult human neural stem cells for cell-re-placement therapies in the central nervous system[J]. Med Aust,2002,177 (6):316-318.
    [31]Levi AD, Dancausse H, Li X, et al. Peripheral nerve grafts pro-moting central nervous system regeneration after spinal cord injury in the primate[J]. Neurosurg,2002, 96 (2 Suppl): 197-205.
    [32]Franklin RJ. Remyelination by transplanted olfactory ensheathing cells[J]. Anat Rec, 2003, 271(1): 71-76.
    [33]Lu J,Féron F,Ho SM,et al. Transplantation of nasal olfactory tissue promotes partial recovery in paraplegic adult rat [J ].Brain Research,2001,889 (1-2):344-357.
    [34] athryn Senior. Olfactory ensheathing cells to be used in spinal cord repair trial[J]. Lancet Neurol,2002,1 (5): 269-272.
    [35]Bergman BS, Kunkel-Bagden E, Schnell L, et al. Recovery from spinal cord injury meaiated by antibodies to neurite growth inhibitors[J]. Nature, 1995,378 :498-501.
    [36]Bomze H, Bulsara KR, Iskandar BJ, et al. Spinal axon regen-eration evoked by replacing two growth cone proteins in adult neurons[J]. Nat Neurosci,2001, 4:38-43.
    [37]Simonen M, Pedersen V, Weinmann O, et al. Systemic dele- tion of the myelin-associated outgrowth inhibitor nogo-A im-proves regenerative and plastic responses after spinal cord inju-ry[J]. Neuron, 2003,38:201-211.
    [38]Kim J, Li S, GrandPréT, et al. Axon regeneration in young adult mice lacking nogo-A/B[J]. Neuron, 2003,38:187-199.
    [39]heng B, Ho C, Li S, et al. Lack of enhanced spinal regenera-tion in nogo-deficient mice[J].Neuron, 2003,38:213-224.
    [40] earson H. Insearch of a miracle[J].Nature, 2003,423:112- 113.
    [41]Ahmed Z, DentRG, SuggateEL, eta.l Disinhibition ofneurotro-phin-induced dorsal rootganglion cell neurite outgrowth on CNS myelin by siRNA-mediated knockdown ofNgR, p75NTR and Rho-A. MolCell Neurosc,i 2005, 28: 509-523.
    [42]SchwabME, Thoenen H. Dissociated neurons regenerate into sciatic butnoto ptic nerve explants in culture irrespective ofneurotrophic factors [J]. J Neurosc,i 1985, 5(9): 2415-2423.
    [43]Kim JE, Li SX, GrandPre T, et a.l Axon regeneration in young adultmice lackingNogo-A/B [J]. Neuron, 2003, 38(2): 187-199.
    [44]SimonenM, Pedersen V, SchwabME, et a.l Systemic deletion of the myelin-associated outgrowth inhibitorNogo-A improves regenerative and plastic responses after spinal cord injury [J]. Neuron, 2003, 38(2):201-211.
    [45]Tobias CA, Shumsky JS, Shibata M,et al. Delayed grafting of BD-NF and NT-3 producing fibroblasts into the injured spinal cord stim-ulates sprouting, partially rescues axotomized red nucleus neurons from loss and atrophy, and provides limited regeneration[J]. Exp Neurol, 2003,184(1):97-113.
    [46]Abe Y, Yamamoto T, Sugiyama Y, et al. Apoptotic cells associated with wallerian degeneration after experimental spinal cord injury: a possible mechanism of oligodendroglial death. J Neurotrauma, 1999; 16:945~952.
    [47]Domeniconi M, Filnin MT, Overcoming inhibitors in myelin to promote axonal regeneration. JOURNAL OF THE NEUROLOGICAL SCIENCES , 2005, 233 (1-2): 43-47.
    [48]Cafferty WBJ, Gardiner NJ, Das P. et al. Conditioning injury-induced spinal axon regeneration fails in interleukin-6 knock-out mice. JOURNAL OF NEUROSCIENCE,2004 24 (18): 4432-4443.
    [49]Fournier AE, GrandPre T, Strittmatter SM. Identification of areceptor mediating Nogo-66 inhibition of axonal regeneration . Nature , 2001, 409(6818):341-346.
    [50] GrandPre T ,Li S , Strittmatter SM. Nogo-66receptor antagonist peptide promotea axonal regeneration. Nature 2002;417(6888):547-51.
    [51]Venkatesh K, Chivatakarn O,Lee H, et al. The Nogo-66 receptor homolog NgR2 is a sialic acid-dependent receptor selective for myelin-associated glycoprotein. JOURNAL OF NEUROSCIENCE,2005, 25 (4): 808-822.
    [52]Cherry Ee, Lin Ng, Bor Luen Tang.Nogos and the Nogo-6 Receptor:Factors Inhibiting CNS Neuron Regeneration.Journal of Neuroscience Research, 2002,67(1002)559-565.
    [53]Yu PP, Xu XM. et al. Rho and axonal regeneration in the central nervous system.PROGRESS IN BIOCHEMISTRY AND BIOPHYSICS.2004 31 (4): 296-298.
    [54]Domeniconi M, Zampieri N. et al.MAG induces regulated intramem-brane proteolysis of the p75 neurotrophin receptor to inhibit neurite outgrowth .NEURON .2005.46 (6): 849-855.
    [55]Yamashita T, Tohyama M. The p75 receptor acts as a displacement factor that releases Rho from Rho-GDI. Nat Neurosci, 2003, 6 (5): 461-467.
    [56]Bandtlow C, Dechant G. et al. From cell death to neuronal regeneration, effects of the p75 neurotrophin receptor depend on interactions with partner subunits. Sci STKE 2004 (235) : 24-27.
    [57]Mi S, Lee X, Shao Z, et al. LINGO-1 is a component of the Nogo-66 receptor / p75 signaling complex. Nat Neurosci, 2004, 7 (3): 221-228.
    [58]DomeniconiM, Cao Z, Spencer T, et al.Myelin-associated gly-coprotein interactswith thenogo66 receptor to inhibit neurite outgrowth. Neuron. 2002, 35(2):283-290.
    [59]Sivasankaran R, Pei J,Wang KC, et al. PKC mediates inhibitory effects ofmyelin and chondroitin sulfate proteoglycans on axonal regeneration. NatNeurosci. 2004,7 (3):261-268.
    [60]Yuste R, Bonhoeffer T. Morphological changes in dendritic spines associated with long-term synaptic plasticity. Annu Rev Neurosci.2001, 24: 1071-1089.
    [61]Raineteau O, Fouad K, Noth P, et al. Functional switch between motor tracts in the presence of the mAb IN-1 in the adult rat.Proc Natl Acad Sci USA. 2002, 98(12):6929-6934.
    [62]Wang X, Chun SJ, TreloarH, et al. Localization ofNogo-A an Nogo-66 receptor proteins at sites of axon-myelin and synaptic cont -act .J Neurosci.2002, 22(13):5505-5515.
    [63]Josephson A, Trifunovski A, W idmer HR, et al. Nogo receptor gene activity: cellular localizationand developmental regulation of mRNA in mice and humans. J Comp Neurol. 2002, 453(3)::292-304.
    [64]O Neill P, Whalley K, Ferretti P. Nogo and Nogo-66 receptor in human and chick: implications for development and regeneration. Dev Dyn. 2004, 231(1):109-121.
    [65]Li W,Walus L,Rabacchi SA,et al.A neutralizing anti-Nogo66 receptor monoclonal antibody reverses inhibition of neurite outgrowth by central nervous system myelin.J Biol Chem 2004 ; 279 (42):43780-43788.
    [66]Kim JE, Liu BP, park JH, et al. Nogo-66 receptor prevents raphesp inal and rubrospinal axon regeneration and lim its functional recovery from spinal cord in ju ry. Neu ron, 2004, 44(3): 439-451.
    [67]Bareure FM, Haudenschild B, Schwab ME. Long-laseing aprouting and gene expressiom changes Induced by the monoclonal antibody IN-1 in the adult spinal cotd . J Neurosci, 2002, 22(16):7097-71110.
    [68]Liu BP , Fournier A , Grandpre T , et al . Myelin-Associsted Glycoprotein as a Functiomal Lingand for the Nogo-66 reveptor Svience ,2002, 297(5584):1190-1193.
    [69]Wang KC,Koprivica V,Kim JA ,et al.Oligodendrocyte—myelin glycoprotein is a Nogo receptor ligand that inhibits neutie outgrowth .Nature , 2002, 417(6892):941-944.
    [70]Zuo J, Neubauer D, Dyess K, Ferguson TA, Muir D. 1998. Degradation of chondroitinsulfate proteoglycan enhances the neurite-promoting potential of spinal cord tissue. Exp Neurol 154:654–662.
    [71]McKerracher L, David S, Jackson DL, Kottis V, Dunn RJ, Braun PE.Identification of myelin-associated glycoprotein as a major myelinderived inhibitor of neurite growth. 1994 Neuron 13:805-811.
    [72]Varga ZM, Schwab ME, Nicholls JG. Myelin-associated neurite growth-inhibitory proteins and suppression of regeneration of immature mammalian spinal cord in culture. Proc Natl Acad Sci 1995, U S A 92:10959–10963.
    [73]Brosamle C, Huber AB, Fiedler M, Skerra A, Schwab ME. Regeneration of lesioned corticospinal tract fibers in the adult rat induced by a recombinant, humanized IN-1 antibody fragment. J Neurosci 2000,20:8061–8068.
    [74]Spillmann AA, Bandtlow CE, Lottspeich F, Keller F, Schwab ME. Identification and characterization of a bovine neurite growth inhibitor (bNI-220). J Biol Chem 1998, 273:19283–19293.
    [75]NaPoli C,Lemieux C & Jorgensen R .Introduction of a chalcone synthase gene into Petunia results in reversible co-suppression of homologous genes in trans .Plant Cell,1990,2:279-289.
    [76]Cogoni C, RomanoN, MacinoG. Suppression of gene expression by homologous transgenes. Antonie Van Leeuwenhoek, 1994,(3)65:205-209.
    [77]GuoS,Kempheus KJ.Par-1,a gene required for establishing polarity in C.elegans embryos,encodes a putative Ser/Thr kinase that is asymmetrically distributed [J].Cell,1995,81∶611-620.
    [78]Fire A, Xu S, Mello CC.et al. Potent and specific genetic interference bydouble-stranded RNA in Caenorhabditis elegans Nature 1998,391 (6669): 806-811.
    [79]Alvarado A S, Newmark P A. Double-stranded RNA specifically disrupts gene express during planarian regeneration[J].Pros Natl Acad Sci USA,1999.96:5049-5054.
    [80]Chuang C. Meyerowitz E M. Specific and heritable genetic interference by double-stranded RNA in Arabidopsis thaliana [J].Proc Natl Acad Sci USA,2000,97 (9):4985-5054.
    [81] Bernstein E, Hammond SM, Hannon GJ. Role for a bidentate ribonuclease in the initiation step of RNA interference. Nature. 2001,409 (6818):363-366.
    [82]Hammond, S. M. , Kobayashi, R. & Hannon, G. J.et al. Argonaute2, a Link Between Genetic and Biochemical Analyses of RNAi.Science 2001,293 (5532): 1146-1150.
    [83]Sijen T, Simmer F, Fire A.et al. On the role of RNA amplification in dsRNA-triggered gene silencing. Cell .2001,107(4):465-476
    [84]Lipardi C, Wei Q, Paterson BM. RNAi as random degradative PCR: siRNA primers convert mRNA into dsRNAs that are degraded to generate new siRNAs. Cell.2001,107(3):297-307
    [85]Hannon GJ. RNA interference. Nature. 2002,418 (6894) :244-251.
    [86]MacManus MT,Sharp PA. Gene silencing in mammals by small interfering RNAs. Nat Rev Genet. 2002,3:737-747..
    [87]Elbashir SM,Lendeckel W, Tuschl T RNA interference is mediated by 21-and 22-nucleotide RNAs..Genes Dev. 2003,17 (4):438-442.
    [88]Elbashir S M, Harborth J, Lendeckel W,et al. Duplexes of 21 nucleotide RNAs mediate RNA interference in cultured mammalian cells. Nature, 2001,411(6836): 494-498.
    [89]Nishikura K. A short primer on RNAi:RNA-directed RNA polymerase acts as a key catalyst. Cell. 2001,107 (4):415-418.
    [90]Gitlin L,Karelsky S. Short interfering RNA confers intracellular antiviral immunity in human cells.Nature.2002,418:430-434.
    [91]Sabine B. Antisense-RNA regulation and RNA interference pathway. Cell,2001,107 (3):309-321.
    [92]Irie N, Sakai N, Ueyama T, et al. Subtype-and speciesspecific knockdown of PKC using short interfering RNA. Biochemical and Biophysical RearchCommunications. 2002,298:738-743.
    [93]Harborth J, Elbashir S M, Bechert K,et al. Identification of essential genes in cultured mammalian cells using small interfering.RNAs J Cell Sci,2001,114 (24): 4557-4565.
    [94]Billy E, Zhang HD, Filipowicz W. Specific interference with gene expression induced by long, double-stranded RNA in mouse embryonal teratocarcinoma cell lines. Proc. Natl. Acad. Sci. USA,2001,98 (25): 14428-14433.
    [95]Jiang M,Milner J, Selective silencing of viral gene expression inHPV-positive human cervical carcinoma cells treated with siRNA,a primer of RNA interference.Oncogene 2002,(21):6041-6048.
    [96]Holen T, Wiiger M.T,Prydz H. Positional effects of short interfering RNAs targeting the human coagulation trigger Tissue Factor.Nucleic Acids Research.2002,30(8):1757-1766.
    [97]Brummelkamp.T.R,Bernads.R,Agami.R.A system for stable expressi-on of short interfering RNAs in Mammalian cells. Science. 2002 ;296:550-553
    [98].Krichevsky AM, Kosik KS. RNAi functions in cultured mammalian neurons.Proc Natl Acad Sci USA.2002,99(18):11926-11929.
    [99].Tuschl T. Expanding small RNA interference. Nature Biotechnol. 2002,20:446-448.
    [100]Sui GH, Soohoo C, Shi Y.et al. A DNA vectorbased RNAi technology to suppress gene expression in mammalian cells. Proc. Natl. Acad. Sci.USA.2002,99(8): 5515-5520.
    [101]Yang SH.Tutton S, Yoon K. Specific Double Stranded RNA Interference in Undifferentiated Mouse Embryonic Stem Cells. Molecular and Cellular Biology. 2001,21:7807-7816.
    [102]Charames GS,Bapat B.Cyclooxygenase-2 knockdown by RNA interfer- ence in col cancer [J].Int J Oncol,2006,28 (2):543-549.
    [103]McCaffrey AP, Meuse L, Pham TT, et al.RNA intereference in adultmice. Nature, 2002, 418(6893): 38-39.
    [104]0Nei 1NJ, Manin RL, Tomlinson ML, et al.RNA-mediated interference as a too 1 for identifying drug Am J Pharmacogenomics, 2001,1(1): 45-53.
    [105]Whittenore SR.Neuronal replacement strategies for spinal cord injury[J]. Neurotrauma,1999,6(8):667-673.
    [106]Wang XY, Zhang JT. Effects of ginsenoside Rg1 on synaptic plasticity of freely moving rats and itsmechanism of action. Acta Pharmacol Sin, 2001,22 : 657-662.
    [107]HassiotisM, Ashwell KW, MarotteLR,et al. GAP-43 Immunoreac-tivity in the brain of the developing and adult wallaby (Macropus eugenii). Anat Embryol, 2002, 26 : 97-118.
    [108]Tolner EA, van Vliet EA, Holtmaat AJ,et al. GAP-43 mRNAand protein expression in the hippocampal and parahippocampal region duringthe course of epileptogenesis in rats. Eur J Neurosci, 2003,17 : 2369-2380.
    [109]Carrasco J, PenkowaM, GiraltM,et al. Role ofmetallo-thionein-III following central nervous system damage. Neurobiol Dis, 2003,13: 22-36.
    [110]McIlvain VA, Robertson DR, Maimone MM,et al. Abnormal thalamocortical pathfinding and terminal arbors lead to enlarged barrels in neonatal GAP-43 heterozygous mice. J Comp Neurol, 2003, 21: 252-264.

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