Toll-like receptor 3 (TLR3)藉著辨識病毒產物雙股RNA (dsRNA)，會產生干擾素α和β，而兩者皆屬於第一型干擾素。而第一型干擾素具有對抗病毒入侵和調控免疫反應的功能。現在已知人工合成的polyinosinic-polycytidylic acid (poly(I:C))能夠有效的刺激巨噬細胞，產生type I interferons。在本篇的研究，我們將探討有什麼訊息傳遞路徑參與在poly(I:C)刺激巨噬細胞所產生的IFN-β的過程中。我們發現PP2 (Src family kinases的抑制劑)可以抑制poly(I:C)刺激老鼠的巨噬細胞RAW264.7所產生的IFN-β。PP2會抑制poly(I:C)刺激下所產生的IFN-β且其 mRNA也顯著降低。另外一方面，SNAP (a NO donor)或8-br-cGMP (a cGMP analogue)皆增加IFN-β mRNA。故IFN-β釋放量的增加，可由其mRNA量的增加來反應。有趣的是，基因剃除iNOS 的表現確實可以使的poly(I:C) 刺激巨噬細胞產生IFN-β的釋放量及Src表現量降低。使用了弱化Src的src-specific siRNA細胞會使的poly(I:C)和SNAP所刺激的IFN-β釋放量下降，不過使用了放回ectopic Src的細胞則又能恢復IFN-β的產生。根據這些結果，我們可以得到一個結論，那就是iNOS參與poly(I:C)-induced IFN-β production，而且Src在這個過程中也扮演重要的角色。
By recognizing double stranded RNA (dsRNA), a product of viral infection, TLR3 can produce type I interferons such interferon alpha and beta (i.e. IFNα/β) that possess anti-viral and immune modulating functions. As the synthetic analogue of dsRNA, polyinosinic-polycytidylic acid (poly(I:C)) can effectively induce the production of IFNα/β in macrophages. In this study, we investigated the signal transduction pathways in IFN-β secretion elicited by poly(I:C). We observed that poly(I:C)-mediated IFN-β generation was PP2 (an inhibitor for Src family kinases(SFKs)) sensitive in murine RAW264.7 cells. Pharmacological blockade of AG (an iNOS inhibitor) and ODQ (a sGC inhibitor) suppressed poly(I:C)-evoked IFN-β mRNA expression. Either SNAP (a NO donor) or 8-br-cGMP (a cGMP analogue) could rescue these defects. We found that the increment of IFN-β could be attributable to their increased transcripts. Interestingly, knockout of iNOS suppressed poly(I:C)-evoked IFN-β secretion and Src induction. Notably, attenuation of Src by src-specific siRNA reduced poly(I:C)-, and SNAP-enhanced IFN-β production in macrophages, and reintroduction of avain Src could rescue this defect. With these results, we concluded that iNOS was critical for poly(I:C)-mediated IFN-β production and Src played a pivotal role in this process.
