TAK1信号通路在高糖诱导骨髓来源巨噬细胞激活中的作用

Objective To investigate the role of transforming growth factor-β activated kinase-1 (TAK1) signaling pathway in the activation of bone marrow derived macrophages (BMDM) induced by high glucose. Methods Purity of mouse BMDM was detected by flow cytometry. The mice macrophages cultured in vitro were stimulated by high glucose and treated with TAK1 specific inhibitor 5Z-7-oxozeaenol. Cells were divided into normal control group (RPMI 1640), osmolality control group (25 mmol/L mannitol), high glucose group (33 mmol/L D-glucose) and inhibitor group (33 mmol/L D-glucose+300 nmol/L 5Z-7-oxozeaenol). Immunocytochemistry and flow cytometry were used to detect macrophage subtype. The expression of monocyte chemotactic protein-1 (MCP-1) and tumor necrosis Factor-α (TNF-α) mRNA were determined by real time PCR. Expressions of p-TAK1, TAK1 binding protein (TAB1), p-JNK, p-p38 MAPK and NF-κB p65 proteins were analyzed by Western blotting. Results The purity of BMDM was about 99.36%. Compared with normal control group, high glucose group had increased percentage of M1 macrophages, increased expression of MCP-1 and TNF-α mRNA (all P＜0.05). Moreover, p-TAK1, TAB1, p-JNK, p-p38 MAPK and NF-κB p65 proteins expression also increased significantly in high glucose group (all P＜0.05). After treatment with inhibitor 5Z-7-oxozeaenol, the effects induced by high glucose were inhibited (P＜0.05). Conclusions High glucose can induce M1 macrophage activation and expression of inflammatory cytokine of BMDM, which can be inhibited 5Z-7-oxozeaenol through inhibiting TAK1/MAPK and TAK1/NF-κB pathway.     

p38信号通路对腹膜间皮细胞p27kip1和纤连蛋白的影响

目的 探讨p38有丝分裂素激活蛋白激酶(MAPK)对高糖诱导的人腹膜问皮细胞(HPMC)p27^kip1的表达和纤连蛋白(FN)分泌的影响。方法 同步化生长融合的HPMC在有或无p38 MAPK抑制剂SB203580的条件下和不同浓度的葡萄糖共同孵育。采用Bradford法测定细胞内总蛋白量。采用逆转录．聚合酶链反应(RT．PCR)方法检测p27^kip1 mRNA的表达。p27^kip1和p38 MAPK蛋白用Western印迹法测定。采用酶联免疫吸附试验(ELISA)测定细胞培养液FN水平。结果 高糖刺激HPMC时细胞内总蛋白量、p27^kip1蛋白及细胞培养液里的FN蛋白水平明显升高。抑制p38 MAPK活性可有效阻断高糖介导的腹膜间皮细胞p27^kip1的表达及FN的分泌。结论 高糖通过p38 MAPK的活化可上调HPMC p27^kip1的表达和FN的分泌。     

高糖和血管紧张素Ⅱ对人肾小管上皮细胞Toll样受体4信号表达及炎性和纤维化因子的影响

Objective To investigate the effects of angiotensinⅡ(AngⅡ) or high glucose on the toll-like receptor 4 (TLR4) expression, inflammatory cytokines and fibrotic factors in human tubular epithelial cells (HK-2), revealing the innate immune-related pathogenesis of diabetic nephropathy (DN) which may have clinical implications. Methods Three TLR4 siRNA sequences were designed and synthetized. After transfection, the most effective siRNA was selected to use for further expriments. The experiment consisted of 2 parts. Part 1: Cells were divided into three groups: normal-glucose group (NG, 5.5mmol/L glucose), mannose group (M, 5.5 mmol/L glucose+19.5 mmol/L mannose), High-glucose group (HG, 25 mmol/L glucose), preliminary validated the effects of high glucose and high osmotic pressure. Part 2: Cells were divided into seven groups: NG group, HG group, AngⅡgroup, AngⅡ+ negative group, HG+ negative group, AngⅡ+ siRNA group and HG+ siRNA group. Real time PCR was used to analyze the mRNA expression of TLR4, myeloid differentiation factor 88 (MyD88), heat shock protein 47 (HSP47). Western blotting was used to observe the protein expression of TLR4, MyD88, HSP47, NF-κB, type Ⅳ collagen (ColIV). ELISA was used to detect the expression of monocyte chemotactic protein-1 (MCP-1) and interleukin-6 (IL-6). Results Compared with NG group, TLR4, MyD88, HSP47 mRNA and TLR4, MyD88, NF-κB, ColⅣ, HSP47 protein were highly expressed under high glucose or AngⅡconditions (P＜0.01), and the expression levels of MCP-1 and IL-6 also increased significantly (P＜0.01). Compared with HG or AngⅡ group, the above indicators were obviously inhibited in the TLR4 siRNA groups (P＜0.01). Comparison between blank vector transfected groups and HG group as well as AngⅡ group indicated no statistic significance (P＞0.05). Conclusions Both AngⅡ and high glucose stimulate TLR4 expression, which result in the up-regulation of inflammatory and fibrotic factors in HK-2. Specific target of TLR4 gene silencing can block the TLR4 pathway that is activated by high glucose and AngⅡ, and thus reduce the inflammatory and fibtogenic factors' release. TLR4 signal is the common innate immune response pathway which induces the release of inflammatory and fibrotic factors in HK-2 under high glucose or high angiotension conditions.     

脂联素及其受体对糖尿病肾病大鼠的保护作用

目的 探讨脂联素（ADPN）及其受体（AdipoR）对糖尿病肾病的保护作用及其可能机制。 方法 （1）64只雌性SD大鼠被随机均分入对照组和实验组：实验组一次性空腹腹腔注射链脲菌素（STZ) 60 mg/kg,诱导糖尿病大鼠模型;对照组腹腔注射等体积的枸橼酸缓冲液。于糖尿病大鼠成模后第2、6、10、12周两组分别测体质量、肾质量、空腹血糖、24 h尿白蛋白排泄量;心内采血检测空腹血清胰岛素;ELISA法检测血、尿脂联素浓度;取肾脏常规制作PAS染色,免疫组化SP法检测肾脏脂联素受体1和2（AdipoR1和AdipoR2）的表达。（2）将NRK-52E细胞分别用含5 mmol/L葡萄糖（正常对照组）、30 mmol/L葡萄糖（高糖组）、30 mmol/L葡萄糖+不同浓度ADPN（终浓度分别为1 mg/L、5 mg/L、10 mg/L）培养,12 h后RT-PCR法检测单核细胞趋化蛋白1（MCP-1） mRNA表达。 结果 （1）造模成功后6、10、12周实验组血清和尿ADPN水平均高于对照组（P < 0.01）,并随着肾脏病变进展而逐渐升高。（2）实验组各时期AdipoR1和AdipoR2在肾脏的表达高于对照组,并随时间逐渐增强,其与血清脂联素水平呈正相关（r = 0.666,P < 0.01;r = 0.684,P < 0.01）。（3）MCP-1 mRNA在高糖组表达较高,加入脂联素以后MCP-1 mRNA表达显著减少（P < 0.05）。 结论 血和尿脂联素水平随糖尿病肾病病程进展而升高,与AdipoR1和AdipoR2的表达亦呈正相关,推测脂联素通过AdipoR直接作用于肾小管,通过减少MCP-1的表达对肾脏起保护作用。     

Effects of benazepril on the expressions of intergrin-linked kinase and α-smooth muscle actin in glomerular mesangial cells exposed to high glucose

Objective To investigate the effect of benazepril on intergrin-linked kinase (ILK) and α-smooth muscle actin (α-SMA) expression in glomerular mesangial cells induced by high-glucose. Methods The mesangial cells from SD rat (HBZY-1) were cultured conventionally and randomly divided into four groups: normal glucose (D-glucose 5.5 mmol/L, group NG), mannitol-treated group (mannitol 20 mmol/L, group MG), high glucose (D-glucose 30 mmol/L, group HG), Benazepril-treated high glucose group (D-glucose 30 mmol/L＋Benazepril 10 μmol/L, group ACEI). Cells from NG, MG, HG, ACEI gronps were harvested after 3, 6, 12, 24, 48 and 72 hours of treatment respectively. The mRNA expressions of ILK and α-SMA were detected by RT-PCR. The protein levels of ILK and α-SMA were detected by Western blotting and immunofluorescence. Results The expressions of ILK mRNA and protein in HG group were significantly increased compared with those in NG group (all P＜0.05). The increased expressions of ILK and α-SMA in HG group were time-dependent and the expression reached the peak at 48 h (ILK, P＜0.05) or 72 h (α-SMA, P＜0.01). The expressions of ILK and α-SMA in ACEI group were lower than those in HG group (all P＜0.01), but failed to rescue to the same level as those in NG. There was no significant differences of ILK expressions between MG group and NG group at the same time point (P＞0.05). The expressions of α-SMA mRNA and protein in MG were higher than that in NG (P＜0.05), which suggest that high osmotic pressure could cause the increasing of α-SMA. Conclusions Benazepril can decrease the expressions of ILK and α-SMA to inhibit the process of fibrosis in DN and mediate the phenotypic transformation of glomerular mesangial cells. The phenotypic transformation of glomerular mesangial cells in glucose may also depend on high osmotic pressure in DN.     

Effects of KIM-1 on high glucose induced the expression of MCP-1 and FN in rat tubular epithelial cells

Objective To evaluate the effects of KIM-1 on high glucose induced the expression of MCP-1 and FN in rat tubular epithelial cells and to explore the possible mechanisms of KIM-1 involved in renal interstitial fibrosis of DN. Methods The rat renal tubular epithelial cells (NRK52E) were cultured in vitro and divided into five groups: Normal control group (D-glucose 5.6 mmol/L), Hypertonic group (D-glucose 5.6 mmol/L＋D-mannitol 24.4 mmol/L), High glucose group (D-glucose 30 mmol/L), Control siRNA group,KIM-1 siRNA group. ELISA assay was used to assess the levels of MCP-1 and FN in the cells supernatant; Western blotting was used to detect the protein expression of KIM-1; RT-PCR was used to detect mRNA expression of KIM-1, MCP-1 and FN. Results Compared with the control group, the protein and mRNA expression of KIM-1 in the high glucose group were increased at 12 h (P＜0.05), and reached the peak at 48 h (P＜0.05); the protein and mRNA expression of MCP-1 and FN in high glucose group were increased at 24 h significantly (P＜0.05), and peaked at 48 h (P＜0.05). Compared with the high glucose group, the protein and mRNA expressions of MCP-1 and FN in KIM-1 siRNA group were decreased (P＜0.05). Conclusions Down-regulating the expression of KIM-1 can significantly inhibit the expression of MCP-1 and FN, which suggests that KIM-1 may be involved in renal interstitial fibrosis of DN by regulating expression of MCP-1 and FN.     

Effects of metformin on expression of AMP - activated protein kinase in rat glomerular mesangial cells

ObjectiveTo observe the effects of metformin on expression of Adenosine 5’- monophosphate (AMP)-activated protein kinase (AMPK), nuclear factor-κB (NF-κB) and transforming growth factor β1 (TGF - β1) in cultured rat glomerular mesangial cells (MCs), and explore its reno - protective mechanisms. Methods MCs were cultured in the medium with normal glucose (group NG, 5.6 mmol/L), high glucose (group HG, 25mmol/L) and different concentrations of metformin (group M1, M2, M3). After 48 h exposure, the supernatants and MCs were collected. The expression of NF-κB and TGF-β1 mRNA was analyzed by real time-PCR. Total-AMPK, phospho-Thr-172 AMPK (p-AMPK), NF -κB p65 and TGF-β1 were visualized by Western blot. ResultsThe real time-PCR and Western blot result showed MCs could express AMPK, NF-κB and TGF-β1 mRNA and protein. After stimulated by HG, the levels of intracellular NF - κB and TGF - β1 expressions were significantly increased compared with group NG (P＜0.05); The levels of NF-κB and TGF-β1 were significantly decreased in group M1, M2 and group M3 compared with group HG in a dose-dependent manner. After stimulated by HG, the level of intracellular p-AMPK were down-regulated compared with group NG(all P＜0.05); The expression of p-AMPK increased with the rising of metformin concentration, presenting the opposite trend (P＜0.05), while the level of total-AMPK protein was unchanged with exposure to HG or different concentrations of metformin(P＞0.05). ConclusionMetformin can suppress the expression of NF- κB and TGF-β1 of glomerular MCs induced by HG via AMPK activation, which may partly contribute to its reno-protection.     

Prostaglandin E2 receptor subtype 3-siRNA reduces the mesangial cell damage induced by TGF-β1through inhibiting MAPK pathway in mice

Objective To investigate the effects and mechanisms of prostaglandin E2 receptor subtype 3 (EP3) on transforming growth factor β1 (TGF-β1)-induced mouse mesangial cells damage. Methods Primary mouse mesangial cells were separated and cultured. Three siRNAs were synthesized and transfected into mesangial cells for silencing EP3 by LipofectamineTM 2000 and the best one was chosen. MCs were grouped into: (1)control group; (2)TGF-β1 (10 μg/L) group; (3)NC-siRNA plus TGF-β1 (10 μg/L) group; (4) EP3-siRNA group; (5)EP3-siRNA plus TGF-β1 (10 μg/L). Then the proliferation of MCs was evaluated by CCK-8 assay. The expression of PGE2 and cAMP in cell supernatant were detected by ELISA. The mRNA and protein expression of fibronectin (FN), connective tissue growth factor (CTGF), cyclooxygenase-2 (COX2), membrane-bound prostaglandin E2 synthase 1 (mPGES1) were detected by real-time quantitative PCR and Western blotting. The phosphorylation of p38 MAPK and ERK1/2 was decected by Western blotting. Results Compared with control group, the cell proliferation induced by TGF-β1 was increased (P＜0.05), the expression of PGE2 and cAMP were improved, mRNA and protein expression of FN, CTGF, COX2 and mPGES1 were up-regulated (all P＜0.05). Compared with TGF-β1 group, the cell proliferation in EP3-siRNA plus TGF-β1 group was reduced, the expression of FN, CTGF, COX2 and mPGES1 mRNA and protein were downregulated (all P＜0.05), the phosphorylation of ERK1/2, p38 MAPK were also declined (P＜0.05). Conclusion EP3-siRNA may reduce TGF-β1-induced cell damage through upregulating the expression of cAMP, repressing the activity of ERK1/2 and p38 MAPK, inhibiting the expression of COX2 mPGES1 and PGE2 by feedback, then decreased the expression of FN and CTGF.     

细胞因子信号传导抑制蛋白1抑制高糖诱导的肾小球系膜细胞单核细胞趋化蛋白1的表达

目的 探讨细胞因子信号传导抑制蛋白1(SOCS-1)对高糖状态下肾小球系膜细胞单核细胞趋化蛋白1（MCP-1）表达的影响。 方法 体外培养人肾小球系膜细胞,应用脂质体2000分别转染pCR3.1-SOCS-1表达质粒和pCR3.1 空质粒载体,G418筛选阳性克隆。分别采用低糖（5.5 mmol/L）、高糖（30 mmol/L）、低糖+甘露醇（24.5 mmol/L甘露醇）和JAK-STAT信号通路抑制剂AG490 （10 μmol/L）进行刺激。Western印迹检测系膜细胞SOCS-1、信号转导和转录活化因子1、3（STAT1、STAT3）及其磷酸化蛋白（p-STAT1、p-STAT3）的表达。ELISA法和放免法测定细胞上清液中MCP-1、FN和Ⅳ型胶原的含量。RT-PCR法检测SOCS-1和MCP-1 mRNA的表达。 结果 高糖刺激系膜细胞SOCS-1蛋白和mRNA表达呈时间依赖性变化, 4 h表达达到峰值,然后逐渐减低,24 h达基线水平。与低糖组相比,高糖组系膜细胞STAT1和STAT3磷酸化水平显著上调（P < 0.01）; MCP-1 mRNA水平表达显著上调[（0.39±0.05）比（0.16±0.02）,P < 0.01];上清液中MCP-1[（459±67）比（241±19） ng/L]、FN[（5.84±0.61）比（3.41±0.31） mg/L]和Ⅳ型胶原[（16.45±2.30）比（9.56±1.52） μg/L] 含量均显著增加（均P < 0.01）。与空载体对照组相比,SOCS-1过表达组系膜细胞STAT1和STAT3的磷酸化水平显著下降（P < 0.05）;MCP-1 mRNA表达下调[（0.34±0.04）比（0.42±0.05）,P < 0.05]; 上清液中MCP-1[(387±47）比（463±56） ng/L]、 FN[（4.61±0.57）比（5.76±0.74） mg/L]和Ⅳ型胶原[(13.4±2.32)比（17.1±2.57） μg/L] 含量显著减少（均P < 0.05）。与高糖组相比,AG490组系膜细胞MCP-1 mRNA（0.31±0.04）表达显著下调;上清液中MCP-1[（361±53） ng/L]、FN[（5.46±0.71）mg/L]和Ⅳ型胶原[（15.2±1.97） μg/L]含量均减少。 结论 SOCS-1过表达抑制高糖状态下肾小球系膜细胞MCP-1及细胞外基质的分泌可能部分是通过影响STAT1和STAT3的激活而实现。     

高糖通过转化生长因子β信号诱导肾小球内皮细胞向肌成纤维细胞转分化

目的 探讨高糖(HG)能否通过转化生长因子β(TGF-β)途径诱导大鼠肾小球内皮细胞向肌成纤维细胞转分化(EndMT).方法 体外培养大鼠肾小球内皮细胞(GEnC),分为正常对照组(NG,5.5 mmol/L)、高糖组(HG,15、30 mmol/L)、TGF-β抑制剂组(HG+LY36,30 mmol/L葡萄糖+10 μmol/L LY364947)以及高渗对照组(M,5.5 mmol/L葡萄糖+25.5 mmol/L甘露醇)和溶剂对照组(D,5.5 mmol/L葡萄糖+1 ml/LDMSO).采用Western印迹法检测各组细胞内皮细胞标志物claudin5和肌成纤维细胞标志物α-SMA表达变化;实时定量PCR法检测细胞TGF-β1和TGF-β2 mRNA表达改变;免疫荧光法观察细胞形态学变化以及血管内皮细胞标志物VE-cadherin和肌成纤维细胞标志物α-SMA的表达.结果 与NG组比较,HG组claudin5蛋白的表达量随葡萄糖浓度增加而降低(P＜0.05),α-SMA蛋白表达量随葡萄糖浓度增加而升高(P＜0.05),TGF-β1和TGF-β2 mRNA表达均升高(P＜0.05).与HG组比较,TGF-β抑制剂组claudin5蛋白表达量升高(P＜0.05),α-SMA蛋白表达降低(P＜0.05).高渗对照组和溶剂对照组改变差异无统计学意义.激光共聚焦免疫荧光结果显示,高糖处理可引起细胞形态由卵圆形向梭形改变,VE-cadherin表达减少,α-SMA表达增加;TGF-β抑制剂组细胞形态无明显改变.与HG组比较,TGF-β抑制剂组VE-cadherin表达增加,α-SMA表达降低(P＜0.05).结论 高糖诱导大鼠肾小球内皮细胞TGF-β表达增加及内皮细胞-肌成纤维细胞转分化.抑制TGF-β可抑制高糖引起的转分化,提示TGF-β参与了高糖引起的肾小球内皮细胞转分化过程.     

虫草素通过下调TGF-β抑制高糖诱导的大鼠肾小管上皮细胞转分化

目的：探讨虫草素对高糖诱导的大鼠肾小管上皮细胞转分化的影响。方法：体外培养大鼠近端肾小管上皮细胞株（NRK52E细胞株）,分为正常对照组（葡萄糖5.5 mmol/L,NG组）、高糖组（葡萄糖30 mmol/L,HG组）、高糖＋虫草素组（葡萄糖30 mmol/L＋虫草素10μg/ml,HG＋C组）。分别于刺激12 h,24 h,48 h后收集细胞。应用定量RT-PCR测定NRK52E TGF-β,E-cadherin,α-SMA mRNA的表达;Western印迹方法检测TGF-β、E-cadherin、α-SMA蛋白的表达。结果：高糖刺激后NRK52E细胞的TGF-β和α-SMA mRNA及蛋白表达明显高于正常糖组（P〈0.01）,而虫草素组TGF-β和α-SMA mRNA及蛋白表达显著低于高糖组（P〈0.05）;高糖诱导的NRK52E细胞E-cadherin mRNA及蛋白水平明显降低（P〈0.01）;而虫草素组NRK52E细胞E-cadherin mRNA及蛋白水平显著高于高糖组（P〈0.05）。结论：虫草素可以明显抑制高糖诱导的大鼠肾小管上皮细胞转分化,其机制可能是通过下调TGF-β实现。     

高糖环境下舒洛地特对大鼠近端肾小管上皮细胞增殖及细胞间黏附分子1表达的影响

目的探讨舒洛地特对高糖培养的大鼠近端肾小管上皮细胞（NRK52E）增殖和细胞间黏附分子1（ICAM-1）表达的影响。方法将NRK52E细胞用5．6mmol／L葡萄糖（NG组）、25mmol／L葡萄糖（HG组）、25mmol／L葡萄糖联合不同浓度舒洛地特（终浓度分别为0．5LRU／ml、1．0LRU／ml、2LRU／ml）于96孔板中分别培养24h、48h、72h后,运用MTT法测定细胞增殖变化。24h后,运用RT-PCR和Western blotting方法检测ICAM-1mRNA和蛋白质的表达。结果HG组细胞增殖及ICAM-1的表达均增强,舒洛地特组能抑制这种趋势并且呈剂量依赖性。结论舒洛地特能通过减少ICAM-1的表达而起到保护肾脏的作用。     

黄连素通过PI3K/Akt/mTOR信号通路抑制高糖条件下的肾脏系膜细胞增殖

目的：探讨黄连素（berberine,BBR）对高糖条件下的大鼠肾脏系膜细胞 HBZY-1 cells （MCS）增殖的影响及其作用机制。方法将对数生长期细胞分成正常糖处理组（NG 组）,高糖组（HG组）和黄连素组（BBR组）。NG组细胞体系常规培养培养,HG 组细胞体系加入40 mmol/L 葡萄糖,BBR组细胞培养体系中加入40 mmol/L葡萄糖＋黄连素30μmol/L。各组细胞培养48 h 后,利用MTT检测各组HBZY-1细胞增殖;RT-PCR检测各组细胞p85,Akt和mTOR基因表达;West-ern blotting检测细胞中 p85、p-p85、Akt、p-Akt,mTOR 和 Collagen-Ⅳ蛋白的变化。结果 NG 组与HG组增值率分别为（25%±3%）和（75%±5%）,与 NG组增值率比较,HG组肾脏系膜细胞增殖率明显增高（P〈0.05）,p85与 Akt mRNA表达水平和蛋白水平均无明显变化（P＆gt;0.05）,但 p-p85、p-Akt,Collagen-Ⅳ蛋白表达水平和 mTOR mRNA 表达与蛋白水平均明显增加（P〈0.05）;BBR 组增值率为（42%±5%）,与 HG 组比较,BBR 组肾脏系膜细胞增值率明显降低（P〈0.05）,但 p-p85、p-Akt、Collagen-Ⅳ蛋白表达水平和 mTOR mRNA 表达与蛋白水平均明显下降（P〈0.05）,而 p85和Akt mRNA和蛋白表达水平均无统计学差异（P〈0.05）。结论黄连素能抑制高糖导致的系膜细胞增殖,其作用可能是通过抑制PI3K/Akt/mTOR信号通路激活。     

Chemerin/ChemR23 promotes high glucose-induced IL-6 and TNF-α expressions in glomerular endothelial cells via p38 MAPK

Objective To observe the role and related mechanism of chemerin and its receptor ChemR23 in glomerular endothelial cells (GEnCs) stimulated by high glucose. Methods Mouse GEnCs were cultured and divided into control group, 20.0 mmol/L high glucose group, 40.0 mmol/L high glucose group and mannitol control group. Then the expressions of interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) in cell culture supernatant as well as the expressions of intracellular protein and mRNA of chemerin, ChemR23, IL-6 and TNF-α were detected. Lentiviral transfection targeting ChemR23 was applied before high glucose- or Chemerin-stimulated, and expressions of supernatant and intracellular mRNA of IL-6 and TNF-α were measured. Meanwhile whether p38 mitogen-activated protein kinase (p38 MAPK) pathway was activated by high glucose was detected. The specific inhibitor of p38 MAPK was added prior to high glucose-stimulated, then supernatant and intracellular mRNA expressions of IL-6 and TNF-α was detected. The supernatant expressions of IL-6 and TNF-α were measured by ELISA. The intracellular protein expression and p38 MAPK phosphorylation activity were detected by Western blotting. The mRNA expression was detected by real time PCR. Results Compared with those in the control group, in high glucose groups the expressions of IL-6, TNF-α and chemerin were significantly increased (all P＜0.05), however, the expressions of ChemR23 did not change (all P＞0.05); the supernatant and mRNA expressions of IL-6 and TNF-α were also elevated in the chemerin group (all P＜0.05). Lentivirus baring shRNA could efficiently suppress ChemR23 expression, and the Chemerin- or high glucose-induced expressions of IL-6 and TNF-α were reduced (all P＜0.05). Also it could significantly reduce the expression of phosphorylated-p38 MAPK (p-p38 MAPK) induced by high glucose (P＜0.05), as high glucose group had higher p-p38 MAPK than control group (P＜0.05). While the high glucose-elevated expressions of IL-6 and TNF-α were significantly attenuated by p38 MAPK inhibitor (all P＜0.05). Conclusions High glucose stimulation can induce the expression of chemerin in GEnCs. By binding to ChemR23, chemerin activates p38 MAPK signaling pathway, and then promotes the expressions of IL-6 and TNF-α. These inflammatory cytokines aggravate inflammation of GEnCs.     

p38丝裂素活化蛋白激酶信号通路在单核细胞趋化蛋白1介导系膜细胞增殖及细胞外基质表达中的作用

目的探讨p38丝裂素活化蛋白激酶（MAPK）信号通路在单核细胞趋化蛋白1（MCP-1）介导大鼠系膜细胞（MCs）增殖及纤连蛋白（FN）和Ⅰ型胶原（ColⅠ）表达中的调控作用。方法用四甲基偶氮唑盐比色法（MTT法）评估不同浓度的MCP-1（12．5、25、50、100ng／ml）及p38MAPK阻断剂SB203580（1、5、10μmol／L）于不同时间对体外培养的大鼠MCs的增殖作用。采用逆转录多聚酶链反应（RT—PCR）检测细胞内FN、ColⅠmRNA的表达。用ELISA法检测上清液FN、ColⅠ蛋白含量。结果MCP-1能刺激MCs的增殖，呈剂量和时间依赖性（P〈0．05），而p38MAPK阻断剂明显抑制上述MCP-1的作用（P〈0.01）。MCP-1能使细胞FN、ColⅠ的表达上调，而p38MAPK阻断剂能抑制其上调表达的作用。结论p38MAPK信号转导通路在MCP-1介导大鼠MCs增殖及FN和ColⅠ表达中起调控作用。MCP-1在系膜增生性肾小球肾炎（MsPGN）的发病中起一定的作用。     

Mediation of inflammatory activation of renal tubular epithelial cells by high mobility group protein box 1 interacting with Toll-like receptor 4

Objective To observe functional changes of renal tubular epithelial cells stimulated by high mobility group protein box 1 (HMGB1) and associated mechanism. Methods Renal tubular epithelial cells (NRK52E) were divided into control group, HMGB1 group and HMGB1+lipopolysaccharide from Rhodobactersphaeroides (LPS RS) group. Toll-like receptor 4 (TLR4) expression was detected by immunofluorescence and Western blotting. Apoptosis rate and cell cycle arrest were identified with flow cytometry. The activation of MAPK signaling pathway and NF-κB were detected by Western blotting. The IL-1, IL-6 and tissue inhibitor of metalloproteinases 2 (TIMP2) mRNA levels were measured by real-time PCR. The secretion levels of IL-1, IL-6 and TIMP2 were measured by protein chips assay. Results TLR4 was expressed by NRK52E cells. Compared with the control group, there were increased cell cycle G1 arrest, MAPK signaling pathway and NF-κB activation in HMGB1 group. Furthermore, IL-1, IL-6 and TIMP2 mRNA levels were increased and IL-1, IL-6 and TIMP2 were secreted by NRK52E when stimulated with HMGB1 (all P＜0.05). However, effects mediated by HMGB1 stimulation could be inhibited by LPS RS (all P＜0.05). Conclusions Inflammatory activation of NRK52E cells can be mediated by the interaction of HMGB1 and TLR4.     

The role and mechanism of macrophage activation induced by exosomes from high glucose-treated renal tubular epithelial cells

Objective To investigate the role and mechanism of macrophage activation induced by exosomes from high glucose-treated renal tubular epithelial cells. Methods (1) The supernatant of renal tubular epithelial cells which were cultured in normal glucose control group (5.5 mmol/L D-glucose) or high glucose group (30.0 mmol/L D-glucose) for 48 h were collected and ultracentrifuged to harvest exosomes. Exosomes were identified by transmission electron microscope and Western blotting. (2) Exosomes were labeled with the green lipophilic fluorescent dye PKH67 and cultured with THP-1 macrophage to investigate whether HK2-derived exosomes could be internalized by THP-1 macrophage. Observing the morphology microscopically and detecting the chemotaxis function of THP-1 macrophages in Transwell chamber after co-cultured with exosomes. The expression of inducible nitric oxide synthase (iNOS), tumor necrosis factor-α (TNF-α), Interleukin-1β (IL-1β), monocyte chemoattractant protein-1 (MCP-1) in cells and supernatants were separately detected by quantitative Real-time PCR (qRT-PCR) and enzyme linked immunosorbent assay (ELISA), and the expression of p-c-Jun NH2-terminal kinase (p-JNK), mitogen-activated protein kinase p-p38 (p-p38MAPK) and nuclear factor κB p65 (NF-κB p65) in THP-1 macrophages were detected by Western blot. Results (1) Vesicles that harvested by ultracentrifugation ranged in size from 30 nm to 100 nm and expressed exosomal marker CD63, TSG101 but absence of calnexin which is a marker of endoplasmic reticulum, suggesting that the exosomes were not contaminated with cells. (2) Results from laser scanning confocal microscope showed that each group of exosomes can be internalized by THP-1 macrophages. Compared with normal glucose exosomes group, high glucose exosomes had increased the expression of iNOS, TNF-α, IL-1β and MCP-1 in THP-1 macrophages (all P＜0.01), moreover, p-JNK, p-p38 MAPK and NF-κB p65 proteins level also increased significantly (all P＜0.01). Conclusions Exosomes from high glucose-treated HK2 cells can induce THP-1 macrophage activation and functional changes through MAPK/NF-κB pathway.     

MicroRNA-148b influences high glucose-induced endoplasmic reticulum stress in rat mesangial cell by targeting AMPKα1

Objective To observe the expression of microRNA-148b (miR-148b) induced by high glucose in rat mesangial cells, and to explore its effect on its target gene AMP-activated protein kinase α1 (AMPKα1) and extracellular matrix excretion. Methods Rat mesangial cells were divided into 3 groups: normal glucose (NG, 5.5 mmol/L glucose) group, hypertonic (MA, 5.5 mmol/L glucose+ 19.5 mmol/L mannitol) group and high-glucose (HG, 25.0 mmol/L glucose) group. MiR-148b expression was detected by real time PCR. Then miR-148b inhibitor was transfected to rat mesangial cells. Their protein expressions of AMPKα1, glucose regulated protein 78 (GRP78), C/EBP homologous protein (CHOP), fibronectin (FN) and collagen Ⅳ were detected by Western blotting. The expression of AMPKα1 mRNA was detected by real time PCR. The expression of collagen Ⅳ was also detected by immunofluorescence. Results Compared with NG group, HG group showed up-regulated miR-148b expression, down-regulated AMPKα1 mRNA and protein expressions, and up-regulated CHOP, GRP78, collagen Ⅳ and FN expressions (all P＜0.05). HG-induced mesangial cells with miR-148b inhibitor had up-regulated AMPKα1 mRNA and protein expressions, and down-regulated CHOP, GRP78, collagen Ⅳ, FN expressions as compared with HG-induced cells without miR-148b inhibitor (all P＜0.05). Conclusions HG can up-regulate miR-148b expression and down-regulate AMPKα1 expression in rat mesangial cells, then activate endoplasmic reticulum stress to induce extracellular matrix excretion. MiR-148b inhibitor up-regulates AMPKα1 expression, inhibits endoplasmic reticulum stress and reduces extracellular matrix excretion.