Department of Pathology, Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China.
Department of Pathology, the Affiliated Hospital of Guilin Medical University, 15 Lequn Road, Guilin, 541001, Guangxi, China.
Lipids Health Dis. 2019 Mar 25;18(1):71. doi: 10.1186/s12944-019-1017-4.
Obesity increases the risk of developing diabetes mellitus. Clinical studies suggest that risk factors like palmitic acid (PA) and lipopolysaccharide (LPS) exist simultaneously in diabetes with obesity. Combination of PA and LPS even at low concentration can induce strong inflammatory reaction. Monocyte chemoattractant protein-1 (MCP-1) is an important inflammatory chemokine related to insulin resistance and type II diabetes. Our previous study using PCR array revealed that LPS and PA synergistically induce MCP-1 mRNA expression in macrophage cells RAW264.7, while the protein expression of MCP-1 in this case was not investigated. Moreover, the underling mechanism in the synergistic effect of MCP-1 expression or production induced by treatment of LPS and PA combination remains unclear.
Protein secretion of MCP-1 was measured by the enzyme-linked immunosorbent assay (ELISA) and mRNA levels of MCP-1 and Toll-like receptor 4 (TLR4) were measured by real-time PCR. Statistical analysis was conducted using SPSS software.
LPS could increase MCP-1 transcription as well as secretion in RAW264.7, and PA amplified this effect obviously. Meanwhile, combination of LPS with PA increased TLR4 mRNA expression while LPS alone or PA alone could not, TLR4 knockdown inhibited MCP-1 transcription/secretion induced by LPS plus PA. Moreover, not NF-κB inhibitor but inhibitors of mitogen-activated protein kinase (MAPK) signaling pathways, including c-Jun NH2-terminal kinase (JNK), extracellular signal-regulated kinase (ERK), and p38 MAPK were found to block MCP-1 generation stimulated by LPS plus PA.
LPS and PA synergistically induced MCP-1 secretion in RAW264.7 macrophage cells, in which MCP-1 transcription mediated by MAPK/TLR4 signaling pathways was involved. Combined treatment of PA and LPS in RAW264.7 cells mimics the situation of diabetes with obesity that has higher level of PA and LPS, MAPK/TLR4/ MCP-1 might be potential therapeutic targets for diabetes with obesity.
肥胖会增加患糖尿病的风险。临床研究表明，肥胖伴糖尿病患者体内同时存在棕榈酸（PA）和脂多糖（LPS）等危险因素。即使在低浓度下，PA 和 LPS 的联合作用也能引发强烈的炎症反应。单核细胞趋化蛋白-1（MCP-1）是与胰岛素抵抗和 2 型糖尿病相关的重要炎症趋化因子。我们之前的研究使用 PCR 阵列表明，LPS 和 PA 协同诱导巨噬细胞 RAW264.7 中 MCP-1mRNA 的表达，而在这种情况下尚未研究 MCP-1 蛋白的表达。此外，LPS 和 PA 联合作用诱导 MCP-1 表达或产生协同效应的潜在机制尚不清楚。
通过酶联免疫吸附试验（ELISA）测量 MCP-1 的蛋白分泌，通过实时 PCR 测量 MCP-1 和 Toll 样受体 4（TLR4）的 mRNA 水平。使用 SPSS 软件进行统计分析。
LPS 可增加 RAW264.7 中 MCP-1 的转录和分泌，PA 明显放大了这种作用。同时，LPS 与 PA 的联合作用增加了 TLR4 mRNA 的表达，而 LPS 单独或 PA 单独作用则不能，TLR4 敲低抑制了 LPS 加 PA 诱导的 MCP-1 转录/分泌。此外，不是 NF-κB 抑制剂，而是丝裂原活化蛋白激酶（MAPK）信号通路的抑制剂，包括 c-Jun NH2-末端激酶（JNK）、细胞外信号调节激酶（ERK）和 p38 MAPK，被发现可阻断由 LPS 加 PA 刺激的 MCP-1 生成。
LPS 和 PA 协同诱导 RAW264.7 巨噬细胞中 MCP-1 的分泌，其中涉及 MAPK/TLR4 信号通路介导的 MCP-1 转录。在 RAW264.7 细胞中联合治疗 PA 和 LPS 模拟了肥胖伴糖尿病患者体内更高水平的 PA 和 LPS 的情况，MAPK/TLR4/MCP-1 可能是肥胖伴糖尿病的潜在治疗靶点。
Zotero 插件
