BACKGROUND/AIMS: Oxidized low-density lipoprotein (ox-LDL) is a powerful atherogen. Toll-like receptor 4 (TLR4) has a pathophysiological role in regulating inflammatory responses and atherosclerosis. Mast cells can infiltrate into the atheromatous plaque and secrete various pro-inflammatory cytokines, which significantly amplify the atherogenic processes and promote plaque vulnerability. Small interfering RNA (siRNA) is an effective method to silence the target genes. We evaluated whether ox-LDL-induced inflammation depended in part on the activation of TLR4-dependent signaling pathways in a cultured human mast cell line (HMC-1). METHOD: HMC-1 cells were cultured, and treated with ox-LDL, TLR4-specific siRNA, or inhibitors of phosphorylation of mitogen-activated protein kinase (MAPKs), and nuclear factor-κB (NF-κB), a critical mediator of inflammation. The expression of monocyte chemoattractant protein-1 (MCP-1), tumor necrosis factor-α (TNF-α) and interleukin 6 (IL-6) was measured subsequently. RESULTS: Ox-LDL increased the expression of TLR4 and secretion of MCP-1, TNF-α and IL-6. Moreover, ox-LDL stimulated the translocation of NF-κB, from the cytoplasm to nucleus. Additionally, phosphorylation of MAPK was greatly increased. These ox-LDL-induced alterations were significantly attenuated by pretreatment with TLR4-specific siRNA. CONCLUSION: Ox-LDL induced inflammatory responses in cultured HMC-1 cells including NF-κB nuclear translocation and phosphorylation of MAPKs, a process mediated in part by TLR4.
BACKGROUND/AIMS: Oxidized low-density lipoprotein (ox-LDL) is a powerful atherogen. Toll-like receptor 4 (TLR4) has a pathophysiological role in regulating inflammatory responses and atherosclerosis. Mast cells can infiltrate into the atheromatous plaque and secrete various pro-inflammatory cytokines, which significantly amplify the atherogenic processes and promote plaque vulnerability. Small interfering RNA (siRNA) is an effective method to silence the target genes. We evaluated whether ox-LDL-induced inflammation depended in part on the activation of TLR4-dependent signaling pathways in a cultured human mast cell line (HMC-1). METHOD: HMC-1 cells were cultured, and treated with ox-LDL, TLR4-specific siRNA, or inhibitors of phosphorylation of mitogen-activated protein kinase (MAPKs), and nuclear factor-κB (NF-κB), a critical mediator of inflammation. The expression of monocyte chemoattractant protein-1 (MCP-1), tumor necrosis factor-α (TNF-α) and interleukin 6 (IL-6) was measured subsequently. RESULTS: Ox-LDL increased the expression of TLR4 and secretion of MCP-1, TNF-α and IL-6. Moreover, ox-LDL stimulated the translocation of NF-κB, from the cytoplasm to nucleus. Additionally, phosphorylation of MAPK was greatly increased. These ox-LDL-induced alterations were significantly attenuated by pretreatment with TLR4-specific siRNA. CONCLUSION: Ox-LDL induced inflammatory responses in cultured HMC-1 cells including NF-κB nuclear translocation and phosphorylation of MAPKs, a process mediated in part by TLR4.
Authors: K Rozsívalová; A Pierzynová; H Kratochvílová; J Lindner; M Lipš; T Kotulák; P Ivák; I Netuka; M Haluzík; T Kučera Journal: Physiol Res Date: 2020-06-25 Impact factor: 1.881
Authors: Ke Yang; Xiao Jie Zhang; Li Juan Cao; Xin He Liu; Zhu Hui Liu; Xiao Qun Wang; Qiu Jin Chen; Lin Lu; Wei Feng Shen; Yan Liu Journal: PLoS One Date: 2014-04-22 Impact factor: 3.240