Project description:Clinical applications of human interferon (IFN)-alpha have met with varying degrees of success. Nevertheless, key molecules in IFN-alpha-induced cell death have not been clearly identified. Our previous study indicated that IFN (alpha, beta and omega) receptor (IFNAR) 1/2- and IFN regulatory factor (IRF) 9-RNA interference (RNAi) completely inhibited the antiproliferative (AP) activity of IFN-alpha in human ovarian adenocarcinoma OVCAR3 cells sensitive to IFN-alpha., followed by transcription of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL). Here, IFNAR1/2- and IRF9-RNAi inhibited the gene expression of TRAIL, but not of Fas ligand (FasL), following IFN-alpha treatment. In fact, TRAIL but not FasL inhibited the proliferation of OVCAR3 cells. IFN-alpha notably up-regulated the levels of TRAIL protein in the supernatant and on the membrane of OVCAR3 cells. Following TRAIL signaling, Caspase 8 inhibitor and BH3 interacting domain death agonist (BID)-RNAi significantly abrogated both AP activities of IFN-alpha and TRAIL. Furthermore, BID-RNAi prevented both IFN-alpha and TRAIL from collapsing the mitochondrial membrane potential (Delta Psi m). Finally, we provide important new evidence that BID overexpression led to a major enhancement of both AP activities of IFN-alpha and TRAIL in human lung carcinoma A549 cells resistant to IFN-alpha. Thus, this study suggests that BID is crucial in IFN-alpha-induced cell death, indicating a notable potential to be a targeted therapy for IFN-alpha resistant tumors. Biological replicate samples were created by treating OVCAR3 cells with IFN-alpha2c (n=8); IFNAR1-RNAi and IFN-alpha2c (n=4); IFNAR2-RNAi and IFN-alpha2c (n=5); ISGF3gamma-RNAi and IFN-alpha2c (n=3); and Negative RNAi and IFN-alpha2c (n=3). For analysis, the eight IFN-alpha2c treated OVCAR3 samples were paired with an untreated OVCAR3 control sample. The 15 RNAi treated OVCAR3 samples were paired with a Negative RNAi control sample.
Project description:Clinical applications of human interferon (IFN)-alpha have met with varying degrees of success. Nevertheless, key molecules in IFN-alpha-induced cell death have not been clearly identified. Our previous study indicated that IFN (alpha, beta and omega) receptor (IFNAR) 1/2- and IFN regulatory factor (IRF) 9-RNA interference (RNAi) completely inhibited the antiproliferative (AP) activity of IFN-alpha in human ovarian adenocarcinoma OVCAR3 cells sensitive to IFN-alpha., followed by transcription of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL). Here, IFNAR1/2- and IRF9-RNAi inhibited the gene expression of TRAIL, but not of Fas ligand (FasL), following IFN-alpha treatment. In fact, TRAIL but not FasL inhibited the proliferation of OVCAR3 cells. IFN-alpha notably up-regulated the levels of TRAIL protein in the supernatant and on the membrane of OVCAR3 cells. Following TRAIL signaling, Caspase 8 inhibitor and BH3 interacting domain death agonist (BID)-RNAi significantly abrogated both AP activities of IFN-alpha and TRAIL. Furthermore, BID-RNAi prevented both IFN-alpha and TRAIL from collapsing the mitochondrial membrane potential (Delta Psi m). Finally, we provide important new evidence that BID overexpression led to a major enhancement of both AP activities of IFN-alpha and TRAIL in human lung carcinoma A549 cells resistant to IFN-alpha. Thus, this study suggests that BID is crucial in IFN-alpha-induced cell death, indicating a notable potential to be a targeted therapy for IFN-alpha resistant tumors.
Project description:Dysregulation of professional APC has been postulated as a major mechanism underlying Ag-specific T cell hyporesponsiveness in patients with patent filarial infection. To address the nature of this dysregulation, dendritic cells (DC) and macrophages generated from elutriated monocytes were exposed to live microfilariae (mf), the parasite stage that circulates in blood and is responsible for most immune dysregulation in filarial infections. DC exposed to mf for 24â96 h showed a marked increase in cell death and caspase-positive cells compared with unexposed DC, while mf exposure did not induce apoptosis in macrophages. Interestingly, 48 h exposure of DC to mf induced mRNA expression of the pro-apoptotic gene TRAIL and both mRNA and protein expression of TNF-alpha. mAb to TRAIL-R2, TNF-R1, or TNF-alpha partially reversed mf-induced cell death in DC, as did knocking down the receptor for TRAIL-R2 using small interfering RNA. Mf also induced gene expression of BH3-interacting domain death agonist (Bid) and protein expression of cytochrome c in DC; mf-induced cleavage of Bid could be shown to induce release of cytochrome c, leading to activation of caspase 9. Our data suggest that mf induce DC apoptosis in a TRAIL- and TNF-alpha-dependent fashion. Experiment Overall Design: Microfilariae and human monocyte derived-DCs were cultuted at a multiplicity of infection of 1:1 for 24hrs for four independent donors. Matching samples exposed to media alone were used for controls The four experimental and 4 control samples were then pooled to create one experoimental and one healthy pool used for microarray analysis.
Project description:Dysregulation of professional APC has been postulated as a major mechanism underlying Ag-specific T cell hyporesponsiveness in patients with patent filarial infection. To address the nature of this dysregulation, dendritic cells (DC) and macrophages generated from elutriated monocytes were exposed to live microfilariae (mf), the parasite stage that circulates in blood and is responsible for most immune dysregulation in filarial infections. DC exposed to mf for 24–96 h showed a marked increase in cell death and caspase-positive cells compared with unexposed DC, while mf exposure did not induce apoptosis in macrophages. Interestingly, 48 h exposure of DC to mf induced mRNA expression of the pro-apoptotic gene TRAIL and both mRNA and protein expression of TNF-alpha. mAb to TRAIL-R2, TNF-R1, or TNF-alpha partially reversed mf-induced cell death in DC, as did knocking down the receptor for TRAIL-R2 using small interfering RNA. Mf also induced gene expression of BH3-interacting domain death agonist (Bid) and protein expression of cytochrome c in DC; mf-induced cleavage of Bid could be shown to induce release of cytochrome c, leading to activation of caspase 9. Our data suggest that mf induce DC apoptosis in a TRAIL- and TNF-alpha-dependent fashion. Keywords: Dendritic Cell, Parasite, Human, Microfilariae