Repetitive Intermittent Hyperglycemia Drives the M1 Polarization and Inflammatory Responses in THP-1 Macrophages Through the Mechanism Involving the TLR4-IRF5 Pathway
Repetitive Intermittent Hyperglycemia Drives the M1 Polarization and Inflammatory Responses in THP-1 Macrophages Through the Mechanism Involving the TLR4-IRF5 Pathway
复制标题
DOI：
10.3390/cells9081892
复制
发表时间：
2020-08-01
期刊：
影响因子：
6
通讯作者：
Ahmad, Rasheed
中科院分区：
文献类型：
--
作者：
Al-Rashed, Fatema;Sindhu, Sardar;Ahmad, Rasheed
重复性间歇性高血糖（RIH）是2型糖尿病（T2 D）相关并发症的独立危险因素。血糖控制不佳或接受强化治疗的T2 D患者通常会出现血糖波动。降低血糖以及血糖波动对于控制T2 D及其大血管/微血管并发症至关重要。干扰素调节因子（IRF）-5位于营养传感器Toll样受体（TLR）-4的下游，是一种重要的代谢调节因子。目前尚不清楚葡萄糖波动如何改变单核细胞/巨噬细胞中的IRF 5/TLR 4表达和炎症反应。为了研究这一点，首先，我们通过实时qRT-PCR测定了来自39名T2 D和48名非糖尿病个体的白色脂肪组织样本中的IRF 5基因表达。接下来，我们在低血糖和高血糖条件下培养THP-1巨噬细胞，并在蛋白质和转录水平上，将IRF 5、TLR 4和M1/M2极化曲线和炎症标志物的表达与对照组（正常对照组）进行比较。使用流式细胞术、ELISA、蛋白质印迹和/或共聚焦显微镜评估蛋白质表达。通过小干扰RNA（siRNA）转染实现IRF 5沉默。数据显示，T2 D患者的脂肪IRF 5基因表达高于非糖尿病患者（p= 0.006），与糖化血红蛋白（HbA 1c）相关（r = 0.47/p< 0.001），胰岛素抵抗的稳态模型评估（HOMA-IR）（r = 0.23/p= 0.03）、肿瘤坏死因子（TNF）-α（r = 0.56/p< 0.0001）、白细胞介素（IL）-1 β（r = 0.40/p= 0.0009）和C-C基序趋化因子受体（CCR）-2（r = 0.49/p< 0.001）表达。与正常血糖（5 mM/L）相比，低血糖（3 mM/L）、持续高血糖（15 mM/L-25 mM/L）和RIH/葡萄糖波动（3-15 mM/L）诱导/上调巨噬细胞中的IRF 5表达（p< 0.05）。RIH/葡萄糖波动还诱导巨噬细胞中的M1极化和炎症特征（CD 11 c、IL-1 β、TNF-α、IL-6和单核细胞趋化蛋白（MCP）-1）。RIH/葡萄糖波动还驱动基质金属蛋白酶（MMP）-9的表达（p< 0.001），其是T2 D患者中心血管并发症的已知标志物。值得注意的是，所有这些变化都被巨噬细胞中的IRF 5沉默所抵消。结论：RIH/葡萄糖波动通过TLR 4-IRF 5通路促进巨噬细胞M1极化和炎症反应，这可能对代谢性炎症具有重要意义。
Repetitive intermittent hyperglycemia (RIH) is an independent risk factor for complications associated with type-2 diabetes (T2D). Glucose fluctuations commonly occur in T2D patients with poor glycemic control or following intensive therapy. Reducing blood glucose as well as glucose fluctuations is critical to the control of T2D and its macro-/microvascular complications. The interferon regulatory factor (IRF)-5 located downstream of the nutrient sensor toll-like receptor (TLR)-4, is emerging as a key metabolic regulator. It remains unclear how glucose fluctuations may alter the IRF5/TLR4 expression and inflammatory responses in monocytes/macrophages. To investigate this, first, we determined IRF5 gene expression by real-time qRT-PCR in the white adipose tissue samples from 39 T2D and 48 nondiabetic individuals. Next, we cultured THP-1 macrophages in hypo- and hyperglycemic conditions and compared, at the protein and transcription levels, the expressions of IRF5, TLR4, and M1/M2 polarization profile and inflammatory markers against control (normoglycemia). Protein expression was assessed using flow cytometry, ELISA, Western blotting, and/or confocal microscopy. IRF5 silencing was achieved by small interfering RNA (siRNA) transfection. The data show that adipose IRF5 gene expression was higher in T2D than nondiabetic counterparts (p= 0.006), which correlated with glycated hemoglobin (HbA1c) (r = 0.47/p< 0.001), homeostatic model assessment of insulin resistance (HOMA-IR) (r = 0.23/p= 0.03), tumor necrosis factor (TNF)-alpha (r = 0.56/p< 0.0001), interleukin (IL)-1 beta (r = 0.40/p= 0.0009), and C-C motif chemokine receptor (CCR)-2 (r = 0.49/p< 0.001) expression. IRF5 expression in macrophages was induced/upregulated (p< 0.05) by hypoglycemia (3 mM/L), persistent hyperglycemia (15 mM/L-25 mM/L), and RIH/glucose fluctuations (3-15 mM/L) as compared to normoglycemia (5 mM/L). RIH/glucose fluctuations also induced M1 polarization and an inflammatory profile (CD11c, IL-1 beta, TNF-alpha, IL-6, and monocyte chemoattractant protein (MCP)-1) in macrophages. RIH/glucose fluctuations also drove the expression of matrix metalloproteinase (MMP)-9 (p< 0.001), which is a known marker for cardiovascular complication in T2D patients. Notably, all these changes were counteracted by IRF5 silencing in macrophages. In conclusion, RIH/glucose fluctuations promote the M1 polarization and inflammatory responses in macrophages via the mechanism involving TLR4-IRF5 pathway, which may have significance for metabolic inflammation.