Amelioration of mitochondrial dysfunction in heart failure through S-sulfhydration of Ca^2＋/calmodulin-dependent protein kinase Ⅱ

OBJECTIVE To determine the functional role of hydrogen sulfide(H_2S) in protecting against mitochondrial dysfunction in heart failure through the inhibition of Ca^(2+)/calmodulin-dependent protein kinaseⅡ(Ca MKⅡ) using wild type and CSE knockout mouse models.METHODS Continuous subcutaneous injection isoprenaline(7.5 mg·kg^(-1) per day),once a day for 4 weeks to induce heart failure in male C57BL/6(6-8 weeks old) mice and CSE-/-mice.150 μmol·L^(-1) H_2O_2 was used to induce oxidative stress in H9c2 cells.Echocardiograph was used to detect cardiac parameters.H&E stain and Masson stain was to observation histopathological changes.Western blot was used to detect protein expression and activity.The si RNA was used to silence protein expression.HPLC was used to detect H_2S level.Biotin assay was used to detect the level of S-sulfhydration protein.RESULTS Treatment with S-propyl-L-cysteine(SPRC) or sodium hydrosulfide(Na HS),modulators of blood H_2S levels,attenuated the development of heart failure in animals,reduced lipid peroxidation,and preserved mitochondrial function.The inhibition Ca MKⅡ phosphorylation by SPRC and Na HS as demonstrated using both in vivo and in vitro models corresponded with the cardioprotective effects of these compounds.Interestingly,Ca MKⅡ activity was found to be elevated in CSE-/-mice as compared to wild type animals and the phosphorylation status of Ca MK Ⅱ appeared to relate to the severity of heart failure.Importantly,in wild type mice SPRC was found to promote S-sulfhydration of Ca MKⅡ leading to reduced activity of this protein however,in CSE-/-mice S-sulfhydration was abolished following SPRC treatment.CONCLUSION A novel mechanism depicting a role of S-sulfhydration in the regulation of Ca MKⅡ is presented.SPRC mediated S-sulfhydration of Ca MKⅡ was found to inhibit Ca MKⅡ activity and to preserve cardiovascular homeostasis.

Ca2+/calmodulin-dependent protein kinase II regulates colon cancer proliferation and migration via ERK1/2 and p38 pathways

AIM To investigate the role of calmodulin-dependent protein kinase Ⅱ(Ca MKⅡ) in colon cancer growth,migration and invasion.METHODS Ca MKⅡ expression in colon cancer and paracancerous tissues was evaluated via immunochemistry. Transcriptional and posttranscriptional levels of Ca MKⅡin tissue samples and MMP2,MMP9 and TIMP-1 expression in the human colon cancer cell line HCT116 were assessed by q RTPCR and western blot. Cell proliferation was detected with the MTT assay. Cancer cell migration and invasion were investigated with the Transwell culture system and woundhealing assay.RESULTS We first demonstrated that CaMK Ⅱ was ove rexpressed in human colon cancers and was associated with cancer differentiation. In the human colon cancer cell line HCT116,the Ca MKII-specific inhibitor KN93,but not its inactive analogue KN92,decreased cancer cell proliferation. Furthermore,KN93 also significantly prohibited HCT116 cell migration and invasion. The specific inhibition of ERK1/2 or p38 decreased the proliferation and migration of colon cancer cells.CONCLUSION Our findings highlight Ca MKⅡ as a potential critical mediator in human colon tumor development and metastasis.

Role of Protein Kinase C in the Activation of Store-operated Ca^(2+) Entry in Airway Smooth Muscle Cells

Store-operated Ca2＋ channels （SOCs） are plasma membrane Ca2＋ permeable channels activated by depletion of intracellular Ca2＋ store. Ca2＋ entry through SOCs is known as store-operated Ca2＋ entry （SOCE）, which plays an important role in the functional regulation of airway smooth muscle cells （ASMCs）. Protein kinase C （PKC） has been shown to have an activating or inhibiting effect on SOCE, depending on cell types and PKC isoforms that are involved. In ASMCs, the effect of PKC on SOCE has not been elucidated so far. In this study, the role of PKC in the activation of SOCE in rat ASMCs was examined by using Ca2＋ fluorescence imaging technique. The results showed that acute application of PKC activators PMA and PDBu did not affect SOCE induced by the sarcoplasmic reticulum Ca2＋-ATPase （SERCA） inhibitor thapsigargin. The non-selective PKC inhibitor chelerythrine significantly inhibited thapsigargin- and bradykinin-induced SOCE. RT-PCR assay identified PKCα, δ and ε isoforms in rat ASMCs. PKCα-selective inhibitor G6976 and PKCε-inhibiting peptide Epsilon-V1-2 had no effect on SOCE; by contrast, PKCδ-selective inhibitor rottlerin attenuated SOCE dramatically, suggesting that PKCδ was the major PKC isoform involved in the activation of SOCE in ASMCs. Moreover, PKC down-regulation by extended exposure to high doses of PMA or PDBu also reduced SOCE, confirming the essential role of PKC in the activation of SOCE in ASMCs. In addition, PKC down-regulation did not influence the expression of stromal interaction molecule 1 （STIM1） and Orai1, two elementary molecules in the regulation and activation of SOCs. These results identified PKCδ as an essential PKC isoform involved in the activation of SOCE, and confirmed that PKC regulates the function of ASMCs in a SOCE-dependent manner.

石杉碱甲对血管性痴呆小鼠海马神经细胞[Ca^(2+)]_i及钙调蛋白、蛋白激酶Ⅱ信使核糖核酸表达的影响

目的 :观察石杉碱甲对血管性痴呆 (VD)小鼠海马神经细胞 [Ca2 + ] i 和钙调蛋白 (CaM) ,Ca2 +钙调蛋白依赖性蛋白激酶Ⅱ (CaMPKⅡ )mRNA表达的影响。方法 :采用双侧颈总动脉线结法 ,制作小鼠VD模型 ,并设假手术对照组 ,石杉碱甲为治疗组 ;术后d 2 9,30测试学习、记忆成绩。利用激光共焦显微镜检测各组海马神经细胞 [Ca2 + ] i;用RT PCR技术检测CaM ,CaMPKⅡmRNA。结果 :模型组[Ca2 + ] i 荧光强度 (44±s 3)显著高于假手术组(2 6± 4) (P <0 .0 1 )和石杉碱甲组 (2 8.5± 2 .5) (P<0 .0 1 ) ;模型组CaMmRNA含量 (0 .76± 0 .2 1 )显著低于假手术组 (1 .1 3± 0 .2 3) (P <0 .0 1 )和石杉碱甲组 (0 .97± 0 .1 9) (P <0 .0 5) ,CaMPKⅡmRNA含量(0 .43± 0 .0 7)显著低于假手术组 (0 .67± 0 .1 0 )(P <0 .0 1 )和石杉碱甲 (0 .61± 0 .0 8) (P <0 .0 1 )。结论 :石杉碱甲可降低VD小鼠海马神经细胞[Ca2 + ] i,提高CaM ,CaMPKⅡmRNA表达水平 。

大鼠脑缺血后P-CaMKⅡ的表达与Ca^(2+)浓度的关系

目的探讨脑缺血后脑组织Ca2+浓度和磷酸化钙调蛋白依赖性蛋白激酶Ⅱ(P-CaMKⅡ)表达的变化及其相关关系。方法采用大鼠大脑中动脉阻断模型,干湿质量法测量脑组织含水量,免疫组化方法检测P-CaMKⅡ的表达,Fura-2/AM荧光法测定水肿周围Ca2+浓度。结果与对照组相比,脑缺血后6 h,P-CaMKⅡ的表达、Ca2+浓度和脑含水量均开始上调,在脑缺血2~3 d表达最强;Ca2+浓度的变化与P-CaMKⅡ的表达强度呈正相关。结论脑缺血后由于细胞内Ca2+超载,导致CaMKⅡ磷酸化作用增强,它们可能共同参与了缺血性脑水肿的形成。

脾虚大鼠壁细胞Ca^(2+)/CaM-PKⅡ活性的变化及黄芪的作用

目的 :观察大黄及利血平两种脾虚模型大鼠壁细胞Ca2 + /CaM PKⅡ的活性变化及黄芪注射液对其的作用。方法 :用Lewin胃袋法、Percoll密度梯度离心分离与纯化壁细胞 ,根据Ca2 + /CaM PKⅡ活性与激活底物磷酸化量成线性关系 ,而底物磷酸化可通过掺入标记的磷酸盐反映 ,从而测定Ca2 + /CaM PKⅡ活性 (pmol/min)。 结果 :大黄、利血平脾虚大鼠胃壁细胞内Ca2 + /CaM PKⅡ活性 (pmol/min)均明显下降 ,黄芪注射液对其有明显上调作用。 结论 :脾虚证在壁细胞胃泌素受体后信号传导通路上病理表现为低下的状态 ,这一通路活性可能为健脾益气中药发挥药理作用的重要靶点之一。

大鼠脑出血后血肿周围Ca^(2+)浓度的变化与磷酸化CaMKⅡ表达的实验研究

目的 探讨脑出血后血肿周围脑组织钙离子浓度和磷酸化的钙调蛋白依赖性蛋白激酶 (P-Ca MK )表达的变化及其相关联系。方法 采用胶原酶注入尾状核建立大鼠脑出血模型 ,干湿重法测量脑组织含水量 ,Fura-2 / AM荧光法测定血肿周围 Ca2 +浓度 ,免疫组化方法检测 P-Ca MK 的表达。结果 与正常组相比 ,脑出血后 6h,Ca2 +浓度、脑含水量和 P-Ca MK 的表达均开始上调 ,第 3天达高峰 ,此后逐渐回落 ,持续 1周仍高于正常水平 ;Ca2 +浓度的变化与 P-Ca MK 的表达强度呈明显正相关。结论 脑出血后细胞内钙超载 ,导致 Ca MK 磷酸化作用增强 。

皮质酮对原代培养的海马神经元及其[Ca^(2+)]_i和钙/钙调蛋白依赖性蛋白激酶Ⅱ表达的影响

目的:探讨皮质酮(CORT)对培养的海马神经元及其[Ca2+]i和钙/钙调蛋白依赖性蛋白激酶Ⅱ(CaMKⅡ)表达的影响和可能的机制。方法:海马神经元被分为不同终浓度的CORT处理组、CORT+MK-8 0 1或高浓度葡萄糖组。采用MTT法、流式细胞术、荧光标记和免疫细胞化学法,观察海马神经元活力、死亡方式[、Ca2+]i和CaMKⅡ表达的变化规律。结果:1 0-6和1 0-5mol/L CORT组,其海马神经元的活力明显降低,分别以凋亡和坏死为主,并使海马神经元[Ca2+]i显著升高;CaMKⅡ的表达明显减少。MK-8 0 1和高浓度葡萄糖均能拮抗1 0-6mol/L CORT对海马神经元的损伤作用。结论:在CORT的作用下,海马神经元发生凋亡和坏死;[Ca2+]i升高可能既是海马神经元损伤的结果,又是引起其发生凋亡和CaMKⅡ表达下降的原因。

加压素(4-8)对大鼠脑内Ca^(2+)/CaM依赖的蛋白激酶Ⅱ自身磷酸化的影响

大鼠皮下注射加压素（AVP）（4-8）1h后，大脑皮层中Ca2+／CaM依赖的蛋白激酶Ⅱ（CaMKⅡ）自身磷酸化程度与对照组比较增高192％，P＜0.001；海马中增高40％，P＜0．05。CaMKⅡ的自身磷酸化程度依赖于Ca2+及CaM的浓度。在用抗CaMKⅡα单克隆抗体对给药1h组样品和对照组样品进行免疫印迹检测时，发现皮下注射AVP（4-8）1h后，大脑皮层中CaMKⅡα亚基的蛋白量没有明显差异。AVP（4－8）的拮抗剂ZDC（C）PR可以明显阻断AVP（4-8）的作用，表明AVP（4-8）刺激CaMKⅡ的活化是通过受体介导的信号转导过程。

过氧化氢对肺动脉内皮细胞环氧合酶-2表达的影响及CaMKⅡ的作用

目的:探讨过氧化氢(H2O2)对肺动脉内皮细胞环氧合酶-2(COX-2)表达的影响及钙-钙调蛋白激酶Ⅱ(CaMKⅡ)在其中的作用。方法:采用活细胞计数法(CCK-8法)检测H2O2处理肺动脉内皮细胞后的细胞活性,采用RT-PCR检测COX-2 mRNA的表达水平,采用Western blotting检测COX-2蛋白质的表达水平。结果:H2O2增强COX-2表达,呈浓度和时间依赖性。100μmol/L H2O2处理肺动脉内皮细胞4 h,COX-2 mRNA和蛋白质表达水平明显高于正常对照组,COX-2 mRNA水平为正常对照组的256.01%±22.36%(P<0.05),蛋白质水平为正常对照组的216.65%±21.52%(P<0.05)。CaMKⅡ特异性抑制剂KN-93能抑制H2O2的这一效应。结论:H2O2可增强肺动脉内皮细胞COX-2基因的表达,CaMKⅡ是H2O2增强肺动脉内皮细胞COX-2基因表达的途径之一。

蛋白磷酸酶1与Ca^(2+)/钙调素依赖性蛋白激酶Ⅱ在心肌病中研究进展

蛋白质的磷酸化与去磷酸化是细胞信号转导过程中最重要的调控方式,其循环过程就像调控分子的开关一样,参与众多生理活动。负责这一修饰调节的是蛋白激酶与蛋白磷酸酶。报道显示人类染色体编码多达500个蛋白激酶,这些蛋白激酶满足人类高度多样性与差异性调控蛋白磷酸化作用,而有趣的是人类编码的蛋白磷酸酶却仅仅约为150个,其中约有40个是丝氨酸/苏氨酸蛋白磷酸酶。越来越多的证据表明蛋白磷酸酶/蛋白激酶调控异常在心肌病中起关键作用。蛋白磷酸酶1(protein phosphatase 1,PP1)是一多功能的丝氨酸/苏氨酸蛋白磷酸酶,研究显示PP1在心肌肥厚和心衰的发生发展过程中起重要作用。而Ca2+/钙调素依赖性蛋白激酶Ⅱ(Ca2+/calmodulin-dependent protein kinaseⅡ,CaMKⅡ)是一种多功能的丝氨酸/苏氨酸蛋白激酶,它作为Ca2+信号转导的关键因子,调节细胞的多种生物学功能,其功能异常可引起肥厚心肌胞内钙稳态失衡进而引起心律失常等心肌病。该文就PP1与CaMKⅡ的功能和心肌病的关系作一综述。

大鼠骨髓间充质干细胞体外诱导分化的心肌样细胞内Ca^(2+)和CaMKⅡ的变化

目的探讨大鼠骨髓间充质干细胞(rat bone m arrow m esenchym al stem cells,MSCs)体外诱导分化为心肌样细胞内游离钙浓度([Ca2+]i)及钙调蛋白依赖性蛋白激酶Ⅱ(CaMKⅡ)的表达变化。方法取健康SD大鼠骨髓,用5-氮杂胞苷体外诱导培养。取诱导培养2、3、4周的MSCs为Ⅰ、Ⅱ、Ⅲ组,另取急性分离的心肌细胞为对照组,分别用激光共聚焦技术和W estern b lot技术检测[Ca2+]i及CaMKⅡ表达水平。结果经荧光探针结合Ca2+后,用激光共聚焦技术检测发现,随诱导培养时间的延长,[Ca2+]i逐渐增加;诱导培养4周的MSCs内[Ca2+]i与对照组比较无显著差异[(100.81±17.64),(100.32±17.10),P>0.05]。各组细胞CaMKⅡ的变化趋势与[Ca2+]i定量分析结果相似,Ⅰ、Ⅱ、Ⅲ组及对照组分别为(322.45±19.43)、(434.43±16.77)、(680.91±20.61)、(682.69±21.03),Ⅲ组与对照组比较P>0.05。结论大鼠MSCs在体外诱导培养4周后已分化为心肌样细胞,其细胞内游离钙浓度和CaMKⅡ蛋白表达水平与正常心肌细胞相似。

基于p38MAPK/SERCA2α通路观察羟基红花黄色素A对大鼠心肌缺血/再灌注损伤的保护作用

目的:基于p38丝裂原活化蛋白激酶/肌质网Ca^(2+)-ATP酶2α(p38MAPK/SERCA2α)通路观察羟基红花黄色素A(HSYA)对大鼠心肌缺血/再灌注损伤(MIRI)的保护作用。方法:120只SD雄性大鼠随机分为假手术组(Sham组)、缺血再灌注组(I/R组)、HSYA 5 mg/kg组、HSYA 10 mg/kg组、HSYA 20 mg/kg组及p38MAPK信号通路抑制剂组(SB203580组)。5、10、20 mg/kg HSYA组大鼠分别灌胃给予对应剂量HSYA,SB203580组给予100µg/kg SB203580,末次灌胃结束后制作MIRI模型,Sham组仅切开左胸暴露心脏不结扎。缺氧4 h、复氧12 h建立H9C2心肌细胞OGD/R损伤模型并分为6组:对照组(Control组)、缺氧复氧模型组(OGD/R组)、5、10、20µmol/L HSYA组及SB203580组,Control组、OGD/R组不进行药物干预。TTC染色测定大鼠心肌梗死面积;超声心动图检测大鼠心脏功能;HE染色观察大鼠心肌组织病理学改变;Annexin V-FITC/PI双染法检测大鼠心肌组织和H9C2细胞凋亡;检测大鼠血清氧化应激及心肌酶指标;ELISA检测大鼠心肌组织和H9C2细胞炎症因子含量;CCK8及EdU染色检测H9C2细胞增殖能力;qRT-PCR检测心肌组织和H9C2细胞p38MAPK、SERCA2αmRNA表达;Western blot检测大鼠心肌组织和H9C2细胞p38MAPK、p-p38MAPK、SERCA2α、B细胞淋巴瘤-2(Bcl-2)、Bcl-2相关X蛋白(Bax)的蛋白表达。结果:10µmol/L或10 mg/kg HSYA能够提高左室射血分数(LVEF)、左室短轴缩短率(LVFS)、Bcl-2、SERCA2α水平,降低肌酸激酶(CK)、乳酸脱氢酶(LDH)、天冬氨酸转氨酶(AST)、超氧化物歧化酶(SOD)活力,降低Bax、肌钙蛋白Ⅰ(cTnⅠ)、丙二醛(MDA)、TNF-α、IL-1β、IL-6、p-p38MAPK/p38MAPK水平,促进心肌细胞增殖,抑制细胞凋亡,减少心肌梗死面积,改善心肌损伤。结论:HSYA能够抑制心肌细胞凋亡、氧化应激及炎症,从而减轻MIRI,其机制可能与p38MAPK/SERCA2α信号通路有关。

Fungus induces the release of IL- 8 in human corneal epithelial cells, via Dectin-1-mediated protein kinase C pathways

AIM: To identify whether Aspergillus fumigatus(A.fumigatus) hyphae antigens induced the release of interleukin-8(IL-8) in anti-fungal innate immunity of cultured human corneal epithelial cells(HCECs) and determine the involvement of intracellular signalling pathways. METHODS: HCECs were treated with A. fumigatus hyphae antigens with different concentrations and time.The cytoplasmic calcium of HCECs were assessed by fluorescence imaging. Western blot was used to detect the expression of Ca2 +-dependent protein kinase C(PKC). The IL-8 levels were determined by specific human IL-8 enzyme-linked immunosorbent assay(ELISA) and reverse transcriptase polymerase chain reaction(RT-PCR). Using a series of pharmacological inhibitors, we examined the upstream signalling pathway responsible for IL-8 expression in response to A.fumigatus hyphae antigens. RESULTS: Cells exposed to A. fumigatus hyphae antigens showed higher level of IL-8 m RNA expression and protein production. We demonstrated here that stimulation of HCECs with A. fumigatus hyphae triggers an intracellular Ca2 +flux and results in the activation of Ca2 +-dependent PKC(α, βⅠ and βⅡ) which can be attenuated by pre-treatment of cells with laminarin,suggesting that Dectin-1 signals pathway induced cytoplasmic calcium and influence the activation of PKC in HCECs. Inhibitors of Ca2 +-dependent PKC(Ro-31-8220 and Go6976) significantly abolished hyphae-induced expression of IL-8.CONCLUSION: Our findings suggest that A. fumigatushyphae-induced IL-8 expression was regulated by the activation of Dectin-1-mediated Ca2 +-dependent PKC in HCECs.

兴奋毒性对海马脑片Ca^(2+)/CaM PK Ⅱ活性的影响

用离体孵育的大鼠海马脑片模型，研究兴奋毒性与Ｃａ２＋／ＣａＭＰＫＩＩ活性的关系。结果表明，外源性谷氨酸或ＮＭＤＡ均可抑制Ｃａ２＋／ＣａＭＰＫＩＩ的活性，此活性的抑制可被ＭＫ８０１完全拮抗，而ＤＮＱＸ却无明显拮抗作用；无胞外Ｃａ２＋时，谷氨酸导致的酶活性抑制程度不如有胞外Ｃａ２＋时显著；无胞外Ｍｇ２＋时，谷氨酸导致的酶活性抑制程度比有胞外Ｍｇ２＋时显著。

Decorin Induces Cardiac Hypertrophy by Regulating the CaMKⅡ/MEF-2 Signaling Pathway In Vivo

Objective:Cardiac hypertrophy is an adaptive reaction of the heart against cardiac overloading,but continuous cardiac hypertrophy can lead to cardiac remodeling and heart failure.Cardiac hypertrophy is mostly considered reversible,and recent studies have indicated that decorin not only prevents cardiac fibrosis associated with hypertension,but also achieves therapeutic effects by blocking fibrosis-related signaling pathways.However,the mechanism of action of decorin remains unknown and unconfirmed.Methods:We determined the degree of myocardial hypertrophy by measuring the ratios of the heart weight/body weight and left ventricular weight/body weight,histological analysis and immunohistochemistry.Western blotting was performed to detect the expression levels of CaMKⅡ,p-CaMKⅡ and MEF-2 in the heart.Results:Our results confirmed that decorin can regulate the CaMKⅡ/MEF-2 signaling pathway,with inhibition thereof being similar to that of decorin in reducing cardiac hypertrophy.Conclusion:Taken together,the results of the present study showed that decorin induced cardiac hypertrophy by regulating the CaMKⅡ/MEF-2 signaling pathway in vivo,revealing a new therapeutic approach for the prevention of cardiac hypertrophy.

MK801拮抗脑缺血导致的Ca^(2+)/CaMPKⅡ活性抑制

目的研究脑缺血兴奋毒性与Ｃａ２＋／ＣａＭＰＫⅡ的关系。方法采用离体孵育的大鼠海马脑片制备“缺血”模型。采用３２Ｐ标记，滤纸片吸附法测定Ｃａ２＋／ＣａＭＰＫⅡ活性。结果①Ｃａ２＋／ＣａＭＰＫⅡ活性随“缺血”时间延长而降低，“缺血”３０ｍｉｎ可降至正常的１６．４％；②单纯过量外源性谷氨酸作用３０ｍｉｎ可导致Ｃａ２＋／ＣａＭＰＫⅡ活性降低；无胞外Ｃａ２＋时，谷氨酸导致的酶活性抑制程度不如有胞外Ｃａ２＋时显著；③ＭＫ８０１对“缺血”导致的Ｃａ２＋／ＣａＭＰＫⅡ活性抑制有部分拮抗作用，２５μｍｏｌ／ＬＭＫ８０１可使“缺血”３０ｍｉｎ的Ｃａ２＋／ＣａＭＰＫⅡ活性恢复至正常的４３．８％。结论脑缺血导致的Ｃａ２＋／ＣａＭＰＫⅡ活性抑制可被ＭＫ８０１部分拮抗，说明其活性抑制与ＮＭＤＡ受体介导的兴奋性毒性作用有关。

CREB和ERK1/2在CaMKⅡδ调控破骨细胞分化中的作用

目的探索c AMP反应原件结合蛋白(CREB)、细胞外信号调节激酶1/2(ERK1/2)在钙调蛋白依赖性激酶Ⅱ(Ca MKⅡ)δ调控破骨细胞分化中的作用及分子机制。方法构建Ca MKⅡδR NA干扰载体并转染小鼠R AW264.7细胞,确定其干扰效率。病毒转染细胞后,用50ng/ml核因子-κB受体活化因子配体(RANKL)诱导,于不同时间点检测CREB、ERK1/2蛋白磷酸化水平。应用ERK1/2信号阻断剂PD98059处理细胞,检测ERK1/2信号阻断对活化T细胞核因子c1(NFATc1)基因表达及破骨细胞分化的影响。结果 Ca MKⅡδ干扰载体在m RNA和蛋白水平的干扰效率分别为77.2%和70.2%。Ca MKⅡδ干扰可明显降低CREB、ERK1/2蛋白磷酸化水平,下调幅度分别为21%~55%和55%~64%。此外,ERK1/2信号阻断明显下调了NFATc1蛋白表达,使破骨细胞数目、骨吸收陷窝数目及面积分别下降了39.3%、50.0%和52.3%。结论 Ca MKⅡδRNA干扰可明显抑制CREB和ERK1/2蛋白磷酸化;CREB和ERK1/2参与了Ca MKⅡδ对破骨细胞分化的调控。

铝对大鼠海马[Ca^(2+)]i和PKC生物活性影响

目的通过观察不同浓度慢性铝暴露对海马长时程增强(long-termpotentiation,LTP)的影响,检测海马细胞内Ca2+浓度和蛋白激酶C(PKC)生物活性,研究慢性铝暴露损伤学习记忆的机制。方法选择断乳后Wistar大鼠,以含有不同浓度AlCl3的蒸馏水进行饲养。3个月后,测定脑铝、血铝、海马细胞内Ca2+,测量记录大鼠海马LTP,用改良的Takai法测定PKC活性的变化。结果(1)各染铝组的[Ca2+]i与对照组比较,差异有统计学意义(P<0.01),但各染铝组间差异无统计学意义。(2)各染铝组PKC活性与对照组比较均降低,差异有统计学意义(P<0.01)。结论慢性铝暴露引起大鼠海马细胞内[Ca2+]i下降,使PKC活性降低,导致下游分子的活性受到影响,破坏LTP的形成,损害学习记忆功能。

锌对大鼠成骨细胞膜Ca^(2+)-ATP酶活性的调节

为了研究锌对大鼠成骨细胞膜Ca2+ -ATP酶和Na+ 、K+ -ATP酶活性的影响及其机制,实验设对照组和3个补锌组。采用孔雀绿比色法同步测定膜Ca2+ -ATP酶和Na+ ,K+ -ATP酶活性,以研究Zn2+ 对酶活性的影响以及蛋白激酶C或钙调素特异性抑制剂对Zn2+ 诱导的成骨细胞膜Ca2+ -ATP酶活性的影响。结果表明,Zn2+ 可以显著提高成骨细胞膜Ca2+ -ATP酶活性,但对Na+ ,K+ -ATPase活性无影响;钙调素特异性抑制剂R24571对Zn2+ 诱导的Ca2+ -ATPase活性无影响,钙调素对膜Ca2+ -ATP酶基础活性也无激活作用;蛋白激酶C特异性抑制剂三氟拉嗪可使Zn2+ 诱导的Ca2+ -ATP酶的活性显著降低。因此,锌可能通过蛋白激酶C介导调节成骨细胞膜Ca2+