Rho激酶抑制剂Y-27632对MRL/lpr狼疮小鼠的保护作用北大核心CSCD

目的探讨Rho激酶抑制剂Y-27632对MRL/lpr狼疮小鼠的保护作用机制。方法 MRL/lpr狼疮小鼠20只随机分为MRL/lpr对照组、5 mg/kg Y-27632处理组,每组10只;野生型对照组C57BL/6小鼠10只。采用ELISA检测各组小鼠血清、脾脏组织中超氧化物歧化酶(SOD)、丙二醛(MDA)水平,ELISA检测血清核因子κB(NF-κB)相关炎症因子白细胞介素6(IL-6)、IL-1β、肿瘤坏死因子α(TNF-α)含量;采用Western blot法检测各组小鼠脾脏组织中硫氧还蛋白结合蛋白(Txnip)/硫氧还蛋白(Trx)、丝裂原激活蛋白激酶(MAPK)相关蛋白胞外信号调节激酶(ERK)、c-Jun氨基末端激酶(JNK)和p38MAPK以及NF-κB的水平;Western blot法检测各组小鼠脾脏T淋巴细胞Txnip、p38MAPK、NF-κB蛋白水平;ELISA检测T淋巴细胞上清液IL-6、IL-1β、TNF-α水平。结果 Y-27632提高MRL/lpr狼疮小鼠血清及脾脏组织SOD水平;降低血清及脾脏组织MDA水平;降低血清、脾脏组织和脾脏T淋巴细胞上清液IL-6、IL-1β、TNF-α水平;抑制脾脏和脾脏T淋巴细胞Txnip、MAPK相关蛋白ERK、JNK和p38MAPK以及NF-κB表达,增加Trx含量。结论 Rho激酶抑制剂Y-27632对MRL/lpr狼疮小鼠有保护作用。     

三七皂苷Rg1抑制脂多糖诱导小胶质细胞激活的机制研究

目的:探讨中药有效成分三七皂苷Rg1(Ginsenoside Rg1,Rg1)对抑制脂多糖(lipopolysaccharide,LPS)诱导的小胶质细胞株BV-2细胞激活的机制。方法:用LPS刺激BV-2细胞构建激活模型,采用四甲基偶氮唑蓝比色法(MTT)检测Rg1对BV-2细胞的活力影响,蛋白质免疫印迹(Western Blot)方法检测不同浓度Rg1(10、20和40μmol/L)对磷酸化的核因子-κB抑制蛋白-α(inhibitorκB-α,IκB-α)和反应结合蛋白(cAMP-responseelement binding protein,CREB)以及促分裂原活化蛋白激酶(mitogen-activated protein kinases,MAPKs)家族的细胞外信号调节激酶(extracellular signal-regulated kinase 1/2,ERK1/2)、c-Jun氨基端激酶(c-Jun N-terminal kinase,JNK)和p38促分裂原活化蛋白激酶(p38 mitogen-activated protein kinase,p38 MAPK)等细胞信号通路蛋白的表达及其变化规律。结果:不同浓度的Rg1明显抑制了LPS诱导的磷酸化IκB-α和CREB蛋白表达以及MAPKs通路(ERK1/2,JNK,p38 MAPK)磷酸化蛋白表达,并且对p38 MAPK表达的影响呈剂量依赖性。结论:Rg1可能通过抑制MAPKs的磷酸化来调控LPS诱导的小胶质细胞株BV-2细胞激活,发挥其神经抗炎的作用。     

结缔组织生长因子促进肾小球系膜细胞合成RANTES部分依赖于p42/44 MAPK

检测结缔组织生长因子(CTGF)是否诱导肾小球系膜细胞分泌正常T细胞表达分泌的活化调节因子(RANTES),并探讨其作用机制。应用CTGF刺激静息的培养大鼠肾小球系膜细胞,在刺激后不同时间点应用RT-PCR方法测定RANTES的mRNA表达,应用酶联免疫吸附试验(ELISA)测定上清液中RANTES。应用趋化试验测定上清液对单核细胞(THP-1)的趋化作用。应用Westernblot测定CTGF对丝裂原激活的蛋白激酶(p42/44MAPK)磷酸化的作用。应用磷酸化p42/44MAPK抑制剂PD98059预处理,观察CTGF对上清液中RANTES分泌的影响。结果显示,应用CTGF(100ng/ml)刺激后,系膜细胞的RANTES的mRNA表达上升,上清液中RANTES分泌量增加。RANTES抗体可部分阻止上清液对单核细胞的趋化作用。CTGF诱导p42/p44MAPK磷酸化,而PD98059可抑制这一作用,并部分抑制CTGF诱导的上清液中RANTES的分泌。研究表明,CTGF可引起系膜细胞分泌RANTES,其作用机制部分依赖于p42/p44MAPK的磷酸化。     

PPARγ配体4i通过抑制NF-κB和MAPK信号通路抑制小鼠巨噬细胞炎性细胞因子的产生

目的探讨新型过氧化物酶体增殖物激活受体γ(PPARγ)配体4i的体外抗炎作用及机制。方法取对数生长期RAW264. 7小鼠腹腔巨噬细胞,经100 ng/m L脂多糖(LPS)诱导,采用ELISA检测10μmol/L 4i对巨噬细胞肿瘤坏死因子α(TNF-α)、白细胞介素6(IL-6)分泌的影响;采用Western blot法检测4i对核因子κBp65(NF-κBp65)、核因子κB抑制蛋白α(IκBα)、c-Jun氨基端激酶(JNK)、胞外信号调节激酶1/2(ERK1/2)、p38丝裂原激活蛋白激酶(p38MAPK)活性的影响,加入不可逆的PPARγ拮抗剂GW9662(5μmol/L)探讨PPARγ在NF-κB和MAPK相关蛋白表达中的作用;采用SYBYL 8. 1软件进行分子对接分析探讨4i与PPARγ蛋白的结合特性。结果 4i显著抑制TNF-α和IL-6的产生呈时间依赖性;不同程度抑制NF-κBp65、IκBα、JNK、ERK1/2和p38MAPK蛋白的磷酸化水平,且抑制作用被GW9662所逆转; 4i能与PPARγ受体较好地结合。结论4i通过激活PPARγ抑制NF-κB和MAPK信号通路相关蛋白的活化,抑制TNF-α、IL-6等的产生,发挥抗炎作用。     

小檗碱抑制人外周血单核细胞COX-2 mRNA及蛋白的表达:c-JUN末端激酶信号转导途径

背景:当细胞受到各种细胞因子及环境刺激时,c-JUN末端激酶信号转导通路可以通过激活不同的受体,对细胞的发育、分化、凋亡、癌变、炎症和免疫反应起调节作用。目的:观察中药小檗碱是否通过c-JUN末端激酶信号转导途径抑制人外周血单核细胞COX-2 mRNA及蛋白表达。方法:取人外周静脉血分离培养单核细胞,分为5组培养:空白对照组、脂多糖组、脂多糖+小檗碱25μmol/L组、脂多糖+小檗碱50μmol/L组、脂多糖+小檗碱100μmol/L组。分别在培养后30min,6h,12h,24h提取细胞,采用RT-PCR测定COX-2 mRNA水平,采用Western blot测定c-JUN末端激酶及COX-2蛋白水平。同时加入选择性c-JUN末端激酶抑制剂,测定COX-2 mRNA及蛋白水平。结果与结论:与空白对照组相比,脂多糖组COX-2 mRNA及蛋白表达明显增强(P0.01)。加入不同浓度小檗碱后COX-2 mRNA及蛋白表达明显被抑制(P0.05),且随着浓度增加,抑制作用更明显,给药后12h,抑制作用最强。但c-JUN末端激酶活性水平无明显变化(P0.05),脂多糖+小檗碱100μmol/L组c-JUN末端激酶活性水平变化明显(P0.05)。加入c-JUN末端激酶抑制剂后,COX-2 mRNA及蛋白水平降低明显(P0.05)。证实小檗碱能抑制人外周血单核细胞COX-2 mRNA及蛋白水平,并呈浓度依赖性,高浓度小檗碱对c-JUN末端激酶活性蛋白表达有明显抑制作用,其可能通过c-JUN末端激酶信号转导途径抑制人外周血单核细胞COX-2 mRNA及蛋白表达。     

蛋白酪氨酸激酶与血管紧张素I受体信号转导

血管紧张素Ｉ（ＡｎｇＩ）受体虽然缺乏内源性蛋白酪氨酸激酶活性,但它却细胞内信号转导的磷脂酶Ｃ磷酸肌醇途径、酶蛋白受体Ｒａｓ途径和ＪＡＫ／ＳＴＡＴ途径中多种信号分子,及其受体本身和粘着斑激酶等分子的酪氨酸磷酸化密切相关。蛋白酪氨酸磷酸化是细胞转导生长与分化信号的重要机制。本文叙述血管平滑肌细胞和心脏细胞在ＡｎｇＩ受体各信号转导途径中的蛋白酪氨酸磷酸化现象。     

丙酮酸通过抑制p38丝裂原激活蛋白激酶(p38MAPK)磷酸化减轻低氧对PC12细胞的损伤北大核心CSCD

目的观察丙酮酸对低氧诱导神经细胞损伤的保护作用及机制。方法采用丙酮酸处理PC12细胞,10 m L/L O2的低氧环境暴露12、24、48 h。MTT法观察细胞增殖情况,检测胱天蛋白酶3(caspase-3)活性观察细胞凋亡情况,ELISA检测白细胞介素1β(IL-1β)、IL-6、肿瘤坏死因子α(TNF-α)的水平,Western blot法检测p38丝裂原激活蛋白激酶(p38MAPK)、磷酸化的p38MAPK(p-p38MAPK)蛋白水平。结果低氧暴露24、48 h,抑制PC12细胞增殖,caspase-3活性增强,IL-1β、IL-6、TNF-α和p-p38MAPK水平增高;丙酮酸处理可显著增加PC12细胞增殖,减少细胞凋亡,降低IL-1β、IL-6、TNF-α水平,抑制p38MAPK的磷酸化水平。结论丙酮酸通过抑制p38MAPK的磷酸化而抑制低氧暴露引起PC12细胞炎症因子的表达,对低氧暴露导致的神经元损伤起保护作用。     

洛美利嗪调控小鼠巨噬细胞极化的机制研究

目的:探究洛美利嗪对小鼠巨噬细胞M1型和M2型极化的调控作用及分子机制。方法:采用RTqPCR及Western blot实验检测洛美利嗪对小鼠骨髓来源的巨噬细胞和Raw 264.7小鼠巨噬细胞M1和M2型极化的影响;Western blot实验检测洛美利嗪对调控巨噬细胞极化的丝裂原活化蛋白激酶(MAPK)、核因子κB(NF-κB)和信号转导及转录激活因子6(STAT6)信号通路的影响。结果:洛美利嗪能够显著抑制脂多糖(LPS)诱导的M1型巨噬细胞炎症因子肿瘤坏死因子α(TNF-α)、白细胞介素6(IL-6)和IL-1β的产生(P0.01),且剂量依赖性地降低M1型极化标志物诱导型一氧化氮合酶(iNOS)的表达(P0.05),同时促进IL-4诱导的M2型巨噬细胞标志物几丁质酶3样蛋白3(CHI3L3/Ym-1)、Fizz-1(found in inflammatory zone-1)和精氨酸酶1(Arg-1)的mRNA和蛋白表达(P0.05)。洛美利嗪能够剂量依赖性地抑制MAPK信号通路中p38 MAPK、细胞外信号调节激酶1/2(ERK1/2)和c-Jun氨基末端激酶1/2(JNK1/2)的磷酸化以及NF-κB信号通路中NF-κB p65的磷酸化,并促进核因子κB抑制因子α(IκBα)的表达(P0.05),进而介导巨噬细胞极化。结论:洛美利嗪可以通过调控MAPK和NF-κB信号通路进而剂量依赖性地抑制小鼠巨噬细胞M1型极化,同时洛美利嗪还可以显著促进M2型极化。     

CpG寡聚脱氧核苷酸(CpG ODN)协同促进脂多糖诱导的小鼠巨噬细胞增殖与迁移

目的探讨CpG寡聚脱氧核苷酸(CpG ODN)对脂多糖(LPS)诱导的巨噬细胞增殖与迁移能力的影响及机制。方法使用1 mg/L LPS处理小鼠RAW264.7巨噬细胞建立体外炎症细胞模型,采用CCK-8法检测CpG ODN(500 nmol/L)对LPS诱导的巨噬细胞增殖的影响,采用Transwell~(TM)实验检测CpG ODN对细胞迁移能力的影响;采用Western blot法检测p38丝裂原激活蛋白激酶(MAPK)、 c-Jun氨基末端激酶(JNK)、胞外信号调节激酶(ERK)、核因子κBp65(NF-κB p65)的蛋白磷酸化水平,同时使用以上通路的抑制剂SB203580、 SP600125、 PD98059、 BAY11-7082,探讨CpG ODN发挥效应的机制;采用实时定量PCR检测CpG ODN对LPS诱导产生的单核细胞趋化蛋白1(MCP-1)、环加氧酶2(COX2)mRNA水平的影响。结果 CpG ODN协同促进LPS诱导的巨噬细胞增殖与迁移,并促进COX2、 MCP-1的转录,增强JNK、 ERK信号通路蛋白的磷酸化水平,并且JNK与ERK信号通路激酶抑制剂可有效降低CpG ODN的协同效应。结论 CpG ODN可通过JNK与ERK途径协同促进LPS诱导的巨噬细胞增殖与迁移并促进COX2、 MCP-1的转录。     

蛋白酪氨酸激酶6对TNF-α诱导的人气道上皮屏障功能减损的影响北大核心CSCD

目的:探讨蛋白酪氨酸激酶6(PTK6)对TNF-α诱导的人气道上皮屏障功能减损的影响及相关机制。方法:体外培养人气道上皮16HBE细胞,予TNF-α刺激,分别转染PTK6 siRNA和recombined PTK6,以转染Scramble siRNA和Empty vector为对照。四甲基偶氮唑盐法(MTT)检测细胞活性;跨皮细胞组抗仪检测细胞跨皮细胞阻抗(TER);辣根过氧化物酶(HRP)流量法反应细胞通透性;RT-PCR检测ZO-1、Occludin mRNA水平;Western blot检测PTK6、ZO-1、Occludin、磷酸化细胞外信号调节激酶1/2(p-ERK1/2)、磷酸化c-Jun氨基端激酶1/2(p-JNK1/2)和磷酸化p38(p-p38)蛋白水平。结果:TNF-α刺激后,细胞ZO-1、Occludin转录及蛋白水平、TER值显著降低,细胞通透性增高,同时PTK6、p-ERK1/2、p-JNK1/2和p-p38蛋白水平显著增高(P<0.05);上调PTK6使ZO-1、Occludin转录及蛋白水平和TER值进一步降低,细胞通透性和p-JNK1/2、p-p38蛋白水平也进一步增高(P<0.05),但下调PTK6后上述指标呈相反变化(P<0.05);上调或下调PTK6对p-ERK1/2无明显影响。结论:下调PTK6可以降低JNK1/2、p38MAPK磷酸化水平,进而改善TNF-α诱导的气道上皮屏障功能减损。     

The signaling cascades of Ganoderma lucidum extracts in stimulating non-amyloidogenic protein secretion in human neuroblastoma SH-SY5Y cell lines

Ganoderma lucidum (GL) is a medicinal mushroom that possesses various pharmacological properties which are also documented in the ancient reports where GL is praised for its effects on the promotion of health and longevity. In this study, we have investigated the effect of GL mycelia extracts on the non-amyloidogenic protein secretion (sAPPα) and the amyloid precursor protein (APP) expression in SH-SY5Y neuroblastoma cells. In order to characterize the signaling pathway which mediates GL-enhanced sAPPα secretion, we used inhibitors of nerve growth factor (NGF) signaling pathways, phosphatidylinositol 3 kinase (PI3K), phospholipase Cγ1 (PLCγ1), protein kinase C (PKC) and extracellular signal-regulated kinase (ERK1/2), to block GL-mediated sAPPα secretion as well as ERK1/2 and PKC activation by using Western blot analysis. Our results provided for the first time evidence that GL mycelia extracts increased APP expression and promoted sAPPα secretion. In addition, GL extracts activated ERK1/2 and PKC phosphorylation. The complex signaling cascades of PI3K and ERK may be responsible for GL-mediated sAPPα secretion.     

L-3-n-butylphthalide regulates amyloid precursor protein processing by PKC and MAPK pathways in SK-N-SH cells over-expressing wild type human APP695

Amyloid precursor protein (APP) is cleaved by α-secretase, within the amyloid-β (Aβ) sequence, resulting in the release of a secreted fragment (αAPPs) and precluding Aβ production. We investigated the effects of a promising anti-AD new drug, l-3-n-butylphthalide (L-NBP), on APP processing and Aβ generation in neuroblastoma SK-N-SH cells overexpressing wild-type human APP695. L-NBP significantly increased αAPPs release, and reduced Aβ generation. The steady-state full-length APP levels were unaffected by L-NBP. It suggested that L-NBP regulated APP processing towards to the non-amyloidogenic α-secretase pathway. Protein kinase C (PKC) and mitogen activated protein (MAP) kinase might be involved in L-NBP-induced αAPPs secretion. L-NBP significantly increased PKCα and ? activations, lowered PKCγ activation and increased the phosphorylation of p44/p42 MAPK. Furthermore, PKC and MAPK inhibitors partially reduced L-NBP-induced αAPPs secretion. The results suggested alternative pharmacological mechanisms of L-NBP regarding the treatment of Alzheimer's disease (AD).     

Amyloid precursor protein processing is separately regulated by protein kinase C and tyrosine kinase in human astrocytes

Regulation of amyloid precursor protein (APP) processing by protein kinase C (PKC) and phosphotyrosine pathways was investigated in cultured human astrocytes. Phorbol 12, 13-dibutyrate (PDBu), a PKC activator, increased secretion of APPalpha 2-3-fold over control values, and GF109203X, a PKC inhibitor, blocked this effect. Similarly, platelet derived growth factor (PDGF) increased the secreted form of APPalpha (sAPPalpha) level two-fold, and genistein, a tyrosine kinase inhibitor, blocked the stimulatory effect of PDGF. Co-treatment of PDGF and PDBu resulted in a five-fold increase in the sAPPalpha production, and genistein and GF109203X did not block the stimulatory effects of PDBu and PDGF, respectively. These results indicate that both PKC and phosphotyrosine pathways are involved in APP processing in human astrocytes, but they act independently. The two pathways appear to converge to mitogen-activated protein kinase (MAPK) because PD98059, a MAPK inhibitor, blocked the effects of PDBu and PDGF on APPalpha secretion.     

Huperzine A regulates amyloid precursor protein processing via protein kinase C and mitogen-activated protein kinase pathways in neuroblastoma SK-N-SH cells over-expressing wild type human amyloid precursor protein 695

Alpha-secretase (alpha-secretase), cleaves the amyloid precursor protein (APP) within the amyloid-beta (Abeta) sequence, resulting in the release of a secreted fragment of APP (alphaAPPs) and precluding Abeta generation. We investigated the effects of the acetylcholinesterase inhibitor, huperzine A (Hup A), on APP processing and Abeta generation in human neuroblastoma SK-N-SH cells overexpressing wild-type human APP695. Hup A dose-dependently (0-10 microM) increased alphaAPPs release. Therefore, we evaluated two alpha-secretase candidates, a disintegrin and metalloprotease (ADAM) 10 and ADAM17 in Hup A-induced non-amyloidogenic APP metabolism. Hup A enhanced the level of ADAM10, and the inhibitor of tumor necrosis factor-alpha converting enzyme (TACE)/ADAM17 inhibited the Hup A-induced rise in alphaAPPs levels, further suggesting Hup A directed APP metabolism toward the non-amyloidogenic alpha-secretase pathway. Hup A had no effect on Abeta generation in this cell line. The steady-state levels of full-length APP and cell viability were unaffected by Hup A. Alpha-APPs release induced by Hup A treatment was significantly reduced by muscarinic acetylcholine receptor antagonists (particularly by an M1 antagonist), protein kinase C (PKC) inhibitors, GF109203X and calphostin C, and the mitogen-activated kinase kinase (MEK) inhibitors, U0126 and PD98059. Furthermore, Hup A markedly increased the phosphorylation of p44/p42 mitogen-activated protein (MAP) kinase, which was blocked by treatment with U0126 and PD98059. In addition, Hup A inhibited acetylcholinesterase activity by 20% in neuroblastoma cells. Our results indicate that the activation of muscarinic acetylcholine receptors, PKC and MAP kinase may be involved in Hup A-induced alphaAPPs secretion in neuroblastoma cells and suggest multiple pharmacological mechanisms of Hup A regarding the treatment of Alzheimer's disease (AD).     

Secreted amyloid precursor protein-α upregulates synaptic protein synthesis by a protein kinase G-dependent mechanism

Secreted amyloid precursor protein-α (sAPPα) is a neuroprotective and neurotrophic protein derived from the parent APP molecule. We have shown that sAPPα enhances long-term potentiation in vivo and can restore spatial memory in rats whose endogenous sAPPα production is impaired. These observations imply that the reduction of sAPPα levels seen in Alzheimer's disease, which occurs alongside increased levels of toxic amyloid-β, may be aetiologically significant. The mechanism by which sAPPα brings about changes in plasticity at synapses remains unresolved. We hypothesised that sAPPα may stimulate changes in synaptodendritic protein synthesis, an important mechanism for normal plasticity. To test this hypothesis, we investigated the effect of sAPPα on protein synthesis in synaptoneurosomes prepared from the hippocampi of adult male Sprague–Dawley rats. sAPPα (10 nM) significantly increased de novo protein synthesis as measured by the incorporation of [³⁵S]-methionine into acid-insoluble proteins. This was dose-dependent and blocked completely by inhibitors of protein synthesis (cycloheximide) and of cGMP-dependent protein kinase (KT5823). Inhibitors of calcium/calmodulin-dependent protein kinases (KN62) and mitogen-activated protein kinase (PD98059) partially blocked the response. Further, the sAPPα-induced increase in protein synthesis was significantly attenuated when measured in synapses isolated from aged rats. These observations imply de novo protein synthesis at synapses may contribute to the long-lasting modulatory effects of sAPPα on synaptic plasticity.     

Ac-HF对Aβ1-42致大鼠皮质原代神经元损伤的保护作用及对α分泌酶活性的影响

目的 探讨贯叶金丝桃素乙酸酯(hyperforin acetate,Ac-HF)对β淀粉样肽(Aβ)1-42毒性损伤大鼠原代培养大脑皮层神经元的作用及对α分泌酶活性的影响及可能机制.方法 采用大鼠原代培养皮层细胞,用MTT法观察Ac-HF对Aβ1-42毒性损伤后的神经细胞活力的影响.用ELASA检测其对α分泌酶活性及可溶性淀粉样前体蛋白(sAPPα)分泌的影响,应用Western blot检其对淀粉样前体蛋白(APP)及解聚金属蛋白酶(a disintegrin and metalloproteinas,ADAM)10表达的影响;并观察Calphostin C(Cal.C)对Ac-HF这些作用的影响.结果 0.1～10.0 μmol/L Ac-HF无细胞毒性(P＞0.05),1.0～50.0 μmol/L Ac-HF可增加Aβ1-42毒性损伤的大鼠皮层神经细胞的活力(P＜0.05),0.1～10.0 μmol/L Ac-HF可使α分泌酶活性增加,sAPPα分泌增多,对APP蛋白表达无影响,使ADAM10表达增多,PKC抑制剂Calphostin C(Cal.C)可抑制Ac-HF对α分泌酶的活性,sAPPα分泌及ADAM10表达的影响.结论 1.0～10.0 μmol/L Ac-HF对Aβ1-42毒性损伤的大鼠皮层神经细胞有保护作用,Ac-HF可通过增加α分泌酶活性及sAPPα分泌产生保护作用,这一作用可能是通过激活PKC通路增加ADAM10表达.     

Estrogen receptor alpha (ERα) phospho-serine-118 is highly expressed in human uterine leiomyomas compared to matched myometrium

It is thought that the growth of uterine leiomyomas may be mediated by the interaction of estrogen receptor alpha (ERalpha) and growth factor pathways and that phosphorylation of ERalpha at serine 118 (ERalpha-phospho-Ser118) is important in this interaction. In this study, immunoblotting and immunohistochemistry were used to investigate the expression of ERalpha-phospho-Ser118, phosphorylated p44/42 mitogen-activated protein kinase (phospho-p44/42 MAPK), and proliferating cell nuclear antigen (PCNA) in human leiomyoma and myometrial tissues during the proliferative and secretory phases of the menstrual cycle. We found that tumors taken from the proliferative phase expressed significantly higher levels of ERalpha-phospho-Ser118, phospho-p44/42 MAPK, and PCNA compared to patient-matched myometria and had significantly higher ERalpha-phospho-Ser118 and PCNA expression compared to secretory phase tumors. Also, enhanced colocalization and association of phospho-p44/42 MAPK and ERalpha-phospho-Ser118 were observed in proliferative phase tumors by confocal microscopy and immunoprecipitation, respectively. These data suggest that ERalpha-phospho-Ser118 may be important in leiomyoma growth and is possibly phosphorylated by phospho-p44/42 MAPK.     

A G protein-associated ERK pathway is involved in LPS-induced proliferation and a PTK-associated p38 MAPK pathway is involved in LPS-induced differentiation in resting B cells

We, previously, showed that PKC-dependent ERK/p38 MAPK activation was inhibited by treating the resting B cell line 38B9 with an anti-MHC class II antibody. Further studies in this work demonstrated that PKA was involved in lipopolysaccharide (LPS)-induced proliferation of the cells, such that the PKC inhibitor activated PKA with concomitant LPS-induced proliferation but not IgG secretion. Consequently, the PKA inhibitor down-regulated ERK and p38 MAPK, and decreased cell proliferation. In addition, the treatment of LPS-stimulated 38B9 cells with PTK inhibitor reduced PKC- and PKA-dependent p38 MAPK activation and reduced the level of IgG secretion rather than the level of proliferation. However, the treatment of LPS-stimulated 38B9 cells with pertussis toxin (PTX), an inhibitor for the G protein-coupled receptor, inhibited the activation of both PKC- and PKA-dependent ERK and significantly reduced LPS-induced proliferation but not IgG secretion. Furthermore, ERK and p38 MAPK inhibitors reduced LPS-induced proliferation and differentiation, respectively, in 38B9 cells in a dose-dependent manner. These results suggest that LPS-induced proliferation of resting B cells is mainly mediated through a G protein-associated PKA/PKC-dependent ERK pathway and that a PTK-associated PKC/PKA-dependent p38 MAPK pathway is mostly involved in LPS-induced differentiation of the resting B cells.