Inositol 1,4,5-trisphosphate receptor in the liver:Expression and function

The liver is a complex organ that performs several functions to maintain homeostasis.These functions are modulated by calcium,a second messenger that regulates several intracellular events.In hepatocytes and cholangiocytes,which are the epithelial cell types in the liver,inositol 1,4,5-trisphosphate(InsP3)receptors(ITPR)are the only intracellular calcium release channels.Three isoforms of the ITPR have been described,named type 1,type 2 and type 3.These ITPR isoforms are differentially expressed in liver cells where they regulate distinct physiological functions.Changes in the expression level of these receptors correlate with several liver diseases and hepatic dysfunctions.In this review,we highlight how the expression level,modulation,and localization of ITPR isoforms in hepatocytes and cholangiocytes play a role in hepatic homeostasis and liver pathology.

Expression of Inositol 1,4,5-trisphosphate Receptor mRNA in Myocardium of Spontaneous Hypertension Rats and Cultured Vascular Smooth Muscle Cells of Rats

Objective\ To investigate expression of inositol 1,4,5 trisphosphate receptor (IP\-3R) mRNA on sacroplasmic reticular in myocardium of spontaneous hypertension rats (SHRs) and cultured vascular smooth muscle cells (VSMC) of rats and effects of perindopril and urapidil on them. Methods\ SHRs were orally given perindopril (1.0 mg·kg\+\{ 1\}·d\+\{ 1\}) or urapidil (15 mg·kg\+\{ 1\}·d\+\{ 1\}) for 24 weeks, respectively. Expression of IP\-3R mRNA was examined by semi quantitative reverse transcription polymers chain reaction (RT PCR) using three oligonuclotide primers for each subtype of IP\-3R with β actin as internal label. Results\ All subtypes of IP\-3R were expressed in myocardium of SHR, WKY and cultured VSMC. Expression of IP\-3R mRNA in left ventricle of SHR was markedly enhanced. Urapidil could down regulate expression of IP\-3R Ⅰand IP\-3R Ⅲ, perindopril slightly increased expression of IP\-3R Ⅱ and decreased expression of IP\-3R Ⅰand IP\-3R Ⅲ in myocardium of SHR. Conclusion\ Our results suggest that expression of IP\-3R mRNA in cardiovascular system could be regulated by urapidil and perindopril.

High expression of type I inositol 1,4,5-trisphosphate receptor in the kidney of rats with hepatorenal syndrome

AIM To detect the expression of typeⅠ inositol 1,4,5-trisphosphate receptor(IP3 RI) in the kidney of rats with hepatorenal syndrome(HRS).METHODS One hundred and twenty-five Sprague-Dawley rats were randomly divided into four groups to receive an intravenous injection of D-galactosamine(D-Gal N) plus lipopolysaccharide(LPS; group G/L, n = 50), D-Gal N alone(group G, n = 25), LPS alone(group L, n = 25), and normal saline(group NS, n = 25), respectively.At 3, 6, 9, 12, and 24 h after injection, blood, liver, and kidney samples were collected. Hematoxylineosin staining of liver tissue was performed to assess hepatocyte necrosis. Electron microscopy was used to observe ultrastructural changes in the kidney. Western blot analysis and real-time PCR were performed to detect the expression of IP3 RI protein and m RNA in the kidney, respectively.RESULTS Hepatocyte necrosis was aggravated gradually, which was most significant at 12 h after treatment with D-galactosamine/lipopolysaccharide, and was characterized by massive hepatocyte necrosis. At the same time, serum levels of biochemical indicators including liver and kidney function indexes were all significantly changed. The structure of the renal glomerulus and tubules was normal at all time points. Western blot analysis indicated that IP3 RI protein expression began to rise at 3 h(P < 0.05) and peaked at 12 h(P < 0.01). Real-time PCR demonstrated that IP3 RI m RNA expression began to rise at 3 h(P < 0.05) and peaked at 9 h(P < 0.01).CONCLUSION IP3 RI protein expression is increased in the kidney of HRS rats, and may be regulated at the transcriptional level.

Altered expression of stromal interaction molecule(STIM)-calcium release-activated calcium channel protein(ORAI) and inositol1,4,5-trisphosphate receptors(IP_3Rs)in cancer:will they become a new battlefield for oncotherapy?

The stromal interaction molecule(STIM)-calcium release-activated calcium channel protein(ORAI) and inositol1,4,5-trisphosphate receptors(IP_3Rs) play pivotal roles in the modulation of Ca^(2+)-regulated pathways from gene transcription to cell apoptosis by driving calcium-dependent signaling processes.Increasing evidence has implicated the dysregulation of STIM-ORAI and IP_3Rs in tumorigenesis and tumor progression.By controlling the activities,structure,and/or expression levels of these Ca^(2+)-transporting proteins,malignant cancer cells can hijack them to drive essential biological functions for tumor development.However,the molecular mechanisms underlying the participation of STIM-ORAI and IP_3Rs in the biological behavior of cancer remain elusive.In this review,we summarize recent advances regarding STIM-ORAI and IP_3Rs and discuss how they promote cell proliferation,apoptosis evasion,and cell migration through temporal and spatial rearrangements in certain types of malignant cells.An understanding of the essential roles of STIM-ORAI and IP_3Rs may provide new pharmacologic targets that achieve a better therapeutic effect by inhibiting their actions in key intracellular signaling pathways.

Temperature-dependence and conformational basis of inositol 1,4,5-trisphosphate receptor regulated by Ca^(2+)

The inositol 1,4,5-trisphosphate (lnsP3) receptor was purified from bovine cerebellum and reconstituted in liposomes composed of phosphatidylcholine (PC) and phosphatidylethanola-mine (PE) (1:1) successfully. No effect of Ca2+ concentration on [3H]-lnsP3 binding to unreconsti-tuted lnsP3 receptor could be observed either at 4℃ or at 25℃, whereas the effect of [Ca2+] on reconstituted lnsP3 receptor depended on the temperature. The Ca2+ concentration outside the proteolipsome ([Ca2+]o) had no detectable effect on lnsP3 binding to lnsP3 receptor at 4℃. In contrast, with increase of [Ca2+]o from 0 to 100 nmol/L at 25℃, the lnsP3 binding activity increased gradually. Then the lnsP3 binding activity was decreased drastically at higher [Ca2+]0 and inhibited entirely at 50 nmol/L [Ca2+]. Conformational studies on intrinsic fluorescence of the reconstituted lnsP3 receptor and its quenching by Kl and HB indicated that the global conformation of reconstituted lnsP3 receptor could not be affected by [Ca2+]o

1,4,5-三磷酸肌醇受体与神经变性疾病

1,4,5-三磷酸肌醇受体(inositol 1,4,5-trisphosphate receptors,IP3Rs)是细胞内质网上的钙离子(cal⁃cium ion,Ca^(2+))通道,通过调控Ca^(2+)参与细胞生物学功能,是维持中枢神经系统正常功能的关键分子。近年来,越来越多的研究发现,IP3Rs结构和功能异常与神经变性疾病如阿尔茨海默病、帕金森病、亨廷顿病、脊髓小脑共济失调等的发病机制密切相关,这些结构和功能异常如何影响IP3Rs功能,及相关钙信号,并且如何在这些疾病的发病和严重程度中发挥作用,仍尚不清楚。IP3Rs如何在神经变性疾病中发挥作用将于本文中进行综述。

Participation of the inositol 1,4,5-trisphosphategated calcium channel in the zona pellucida- and progesterone-induced acrosome reaction and calcium influx in human spermatozoa

The acrosome reaction is a prerequisite for fertilization,and its signaling pathway has been investigated for decades.Regardless of the type of inducers present,the acrosome reaction is ultimately mediated by the elevation of cytosolic calcium.Inositol 1,4,5-trisphosphate-gated calcium channels are important components of the acrosome reaction signaling pathway and have been confirmed by several researchers.In this study,we used a novel permeabilization tool BioPORTER?and first demonstrated its effectiveness in spermatozoa.The inositol 1,4,5-trisphosphate type-1 receptor antibody was introduced into spermatozoa by BioPORTER?and significantly reduced the calcium influx and acrosome reaction induced by progesterone,solubilized zona pellucida,and the calcium ionophore A23187.This finding indicates that the inositol 1,4,5-trisphosphate type-1 receptor antibody is a valid inositol 1,4,5-trisphosphate receptor inhibitor and provides evidence of inositol 1,4,5-trisphosphate-gated calcium channel involvement in the acrosome reaction in human spermatozoa.Moreover,we demonstrated that the transfer of 1,4,5-trisphosphate into spermatozoa induced acrosome reactions,which provides more reliable evidence for this process.In addition,by treating the spermatozoa with inositol 1,4,5-trisphosphate/BioPORTER?in the presence or absence of calcium in the culture medium,we showed that the opening of inositol 1,4,5-trisphosphate-gated calcium channels led to extracellular calcium influx.This particular extracellular calcium influx may be the major process of the final step of the acrosome reaction signaling pathway.

大鼠心肌缺血再灌注时心肌细胞核1,4,5三磷酸肌醇受体结合特性改变的研究

目的观察大鼠心肌缺血再灌注时心肌细胞核1,4,5三磷酸肌醇受体(IP3R)的结合特性改变,进一步探索心肌缺血再灌注时细胞凋亡的病理机制。方法TUNEL技术检测心肌细胞核凋亡率。蔗糖密度梯度离心法提纯心肌细胞核,放射配体分析法检测心肌细胞核膜上IP3R的结合特性变化。结果①缺血再灌注损伤(IRI)组大鼠心肌细胞凋亡率高于对照组(P<0.01)。②大鼠心肌缺血再灌注损伤时,心肌细胞核IP3R的最大结合容量Bmax较假手术组增加2.6倍;而其亲和力Kd值无明显变化。③IRI组心肌细胞核IP3R经激活的PKC磷酸化后结合特性增强1.54倍,对照组核IP3R经PKC磷酸化后结合特性无明显改变。④[Ca2+]对IRI组及假手术组心肌细胞核IP3R的调节均呈双相性,胞浆钙超载状态下([Ca2+]为5μmol·L-1时)较正常胞浆钙浓度下([Ca2+]为100nmol·L-1时),两组核IP3R结合特性均增强,[Ca2+]为100μmol·L-1时,两组核IP3R结合特性降低。结论大鼠心肌心肌缺血再灌注损伤病理情况下心肌细胞核IP3R结合特性增强,致核内钙浓度([Ca2+]n)增高,这可能是心肌缺血再灌注损伤中心肌细胞凋亡的主要病理机制之一。

肿瘤坏死因子-α增强肝肾综合征时肾脏I型1,4,5-三磷酸肌醇受体表达

目的:通过观察TNF-α对肾组织中Ⅰ型IP3R表达的影响来探讨肝肾综合征的发病机制.方法:制备大鼠离体肾灌注模型,随机分成对照组(A组)、肝素处理组(B组)、TNF-α处理组(C组),留取的标本应用免疫组织化学技术、Westernblot及实时定量PCR检测肾组织Ⅰ型IP3R蛋白的定位、表达及mRNA的变化.结果:Ⅰ型IP3R主要分布于肾小球系膜细胞和血管平滑肌细胞的胞质内.免疫组化结果显示,C组与A组相比棕褐色颗粒着色的阳性细胞明显增多,有显著性差异(U=2.26,P<0.05);B组与A组相比阳性染色细胞无明显减少(P>0.05);Western blot结果与免疫组织化学结果相一致:C组与A组相比Ⅰ型IP3R蛋白表达水平明显增高,有显著性差异(1.89±0.11vs0.55±0.03,P<0.05);B组与A组相比无显著性差异(P>0.05);实时定量PCR结果显示:C组与A组相比Ⅰ型IP3R mRNA的表达水平明显增高,有显著性差异(7.99±0.12vs1.00±0.05,P<0.05);B组与A组相比无显著性差异(P>0.05).结论:TNF-α可增强肾小球系膜细胞和血管平滑肌细胞Ⅰ型IP3R蛋白的表达,且Ⅰ型IP3R mRNA也呈增加趋势.

TNF-α增强主动脉平滑肌细胞内1型1,4,5-三磷酸肌醇受体表达参与感染性休克的发生机制

目的研究TNF-α对主动脉平滑肌细胞(VSMC)内1型1,4,5-三磷酸肌醇受体(IP3RⅠ)表达的影响,揭示TNF-α影响VSMC收缩功能参与感染性休克的发生机制。方法原代分离培养大鼠VSMC。按TNF-α处理的不同时间点(0、4、8、24h)分4组。分别应用Western blot、免疫荧光、RT-PCR、双荧光素酶检测方法,观察TNF-α对IP3RⅠmRNA、蛋白表达及其启动子活性的影响。结果 TNF-α处理组细胞内IP3RⅠ分布未见变化,8、24h组荧光强度增强提示IP3RⅠ蛋白含量增加,IP3RⅠ蛋白表达升高(4h:1.059±0.005 vs 1.000±0.002,P=0.010;8h:2.416±0.042 vs 1.000±0.002,P<0.01;24h:2.138±0.010vs 1.000±0.002,P<0.01,n=9),IP3RⅠmRNA表达明显增加(4h:2.260±0.889 vs 1.00±0.02,P=0.193;8h:5.449±2.279 vs1.00±0.02,P=0.000;24h:3.049±1.684 vs 1.00±0.02,P=0.042,n=9)。转染PGL3-IP3RⅠpromoter质粒后TNF-α组IP3RⅠ启动子活性明显增强(3.56±0.65 vs 1.00±0.05,P=0.020,n=9)。结论 TNF-α可上调IP3RⅠ基因启动子活性,从而引起IP3RⅠ蛋白表达升高,增强VSMC内IP3Rs系统介导的Ca2+释放作用,这可能是TNF-α影响VSMC收缩功能参与感染性休克血管调控的机制之一。

1,4,5-三磷酸肌醇受体与心血管疾病

1,4,5-三磷酸肌醇受体是一种细胞内Ca2+释放通道,它与1,4,5-三磷酸肌醇结合后,引起Ca2+浓度发生改变,从而参与钙信号转导,调节多种细胞代谢活动。近年来,越来越多的研究提示其参与心力衰竭、心肌肥厚、心房颤动等心血管疾病的发生。现就三磷酸肌醇受体的结构、分布、激活Ca2+通道开放以及与心血管疾病发病机制的研究进展等作一综述。

1,4,5-三磷酸肌醇受体3促进常染色体显性遗传性多囊肾病囊泡生长

本文旨在阐明1,4,5-三磷酸肌醇受体3(inositol 1,4,5-trisphosphate receptor 3,IP_(3)R3)在常染色体显性遗传性多囊肾病(autosomal dominant polycystic kidney disease,ADPKD)肾囊泡发生、发展过程中的作用,为ADPKD的治疗提供理论基础。使用2-氨基乙氧基二苯基硼酸盐(2-aminoethoxy-diphenyl borate,2-APB)和shRNA抑制IP_(3)R3的表达水平,通过MDCK(MadinDarby canine kidney)囊泡模型、胚胎肾囊泡模型、肾脏特异性Pkd1敲除(PKD)小鼠模型探究IP_(3)R3在囊泡生长过程中的作用,并通过Western blot、免疫荧光染色技术探究IP_(3)R3调控囊泡生长的分子机制。结果显示,在PKD小鼠肾脏中,IP_(3)R3的表达水平显著升高。在胚胎肾囊泡模型和MDCK囊泡模型中,通过2-APB或shRNA抑制IP_(3)R3的表达可显著延缓囊泡的生长。机制研究结果显示,在ADPKD肾囊泡生长过程中,异常活化的cAMP-PKA信号通路促进了IP_(3)R3的表达,并促进其从内质网向细胞间连接处转运。IP_(3)R3的上调以及亚细胞定位的异常激活MAPK和mTOR信号通路,加速细胞周期,引起囊泡上皮细胞异常增殖,最终促进囊泡的生长。上述结果提示,IP_(3)R3在促进ADPKD肾囊泡生长过程中发挥重要作用,抑制IP_(3)R3的表达及亚细胞再分布过程可以有效延缓囊泡的生长,而IP_(3)R3有望成为ADPKD的治疗靶点。

暴发性肝衰竭时肾脏Ⅰ型1，4，5-三磷酸肌醇受体表达增加

目的 研究暴发性肝衰竭小鼠肾脏I型1,4,5-三磷酸肌醇受体（IP3R）表达的变化。方法 采用D-氨基半乳糖和内毒素联合腹腔注射制备暴发性肝衰竭小鼠动物模型。动物随机分为4组,即等渗盐水对照组、LPS对照组、D-氨基半乳糖对照组、暴发性肝衰竭组（2、6、9 h）。应用免疫组织化学、Western blot及RT-PCR技术检测暴发性肝衰竭进程中,小鼠肾脏IP3R蛋白质的定位、表达及mRNA表达的变化。结果 Ⅰ型IP3R主要分布于肾小球系膜细胞和血管平滑肌细胞的胞浆内。在暴发性肝衰竭组小鼠,6 h时I型IP3R免疫组织化学染色阳性细胞开始增加,9 h时更为明显（6 h：x^2=7．11,P〈0．01,9 h： x^2=9．15,P〈0.01）。Western blot结果与免疫组织化学结果一致,6 h时开始增加（t=3．16,P〈0．05）,9 h达到最高值（t=5．43,P〈0．01）,与等渗盐水对照组相比差异有统计学意义。RT PCR结果显示暴发性肝衰竭小鼠2 h时I型IP3R mRNA即开始增加,6 h时达到最高值,9 h时有所恢复,但与等渗盐水对照组相比差异均有统计学意义（2 h：t=2．47,P〈0．05,6 h：t=4．42,P〈0.01,9 h：t=2．16,P〈0．05）。结论 在暴发性肝衰竭进程中,肾脏I型1,4,5-三磷酸肌醇受体表达增强,其mRNA也呈上调趋势。

肝硬化大鼠肾小球血管袢和肾小球前小动脉Ⅰ型1,4,5-三磷酸肌醇受体的表达

目的 探讨跨膜信息传导机制在肝硬化并肝肾综合征发病机制中的作用。 方法 应用40％四氯化碳制备肝硬化动物模型,免疫组织化学方法检测肝硬化大鼠肾小球血管袢和肾小球前小动脉的Ⅰ型1,4,5-三磷酸肌醇受体(IP3R),观察其表达情况。 结果 肾小球血管袢和肾小球前小动脉Ⅰ型IP3R表达,实验组分别为:4.97±1.34、4.09±1.14,正常大鼠组分别为:2.43±1.67、1.83±1.32,两组之间差异有非常显著性,t值分别为3.43和3.70,P值分别为0.0037和0.0022;实验组肾小球血管袢和肾小球前小动脉Ⅰ型IP3R表达,差异有显著性,t值为2.28,P=0.0458。大鼠肾脏常规病理检查均无改变。 结论 跨膜信息传导机制在肝硬化并肝肾综合征发生机制中发挥重要作用。

肌醇1,4,5-三磷酸受体与阿尔茨海默病

细胞内质网上的肌醇1,4,5-三磷酸受体(inositol 1,4,5-trisphosphate receptors, IP3Rs)是调节Ca^2+释放的重要离子通道。Ca^2+稳态是维持机体细胞生理功能的重要基础,Ca^2+信号参与酶激活、囊泡释放和细胞凋亡等多种细胞过程。研究表明,Ca^2+信号异常与阿尔茨海默病(Alzheimer’s disease, AD)密切相关,神经元中钙信号异常可以导致细胞稳态失衡、突触功能丧失,甚至细胞死亡。现对IP3Rs的生物特性及其介导的Ca2+释放在阿尔茨海默病发生发展过程中的作用进行综述。

下调XBP1s通过抑制ITPR介导的线粒体功能障碍改善肾小管上皮细胞缺氧/复氧损伤

目的 探讨剪接型X盒结合蛋白1(XBP1s)对小鼠肾小管上皮细胞缺氧/复氧(H/R)损伤的影响及其作用机制。方法 将小鼠肾小管上皮细胞分为腺病毒阴性对照组(Ad-shNC组)、靶向沉默XBP1s腺病毒组(Ad-shXBP1s组)、Ad-shNC+H/R组、Ad-shXBP1s+H/R组。检测各组细胞凋亡水平、线粒体活性氧活性、线粒体膜电位及线粒体钙离子水平。使用染色质免疫共沉淀测序(ChIP-seq)分析XBP1s调控肌醇1,4,5-三磷酸受体(ITPR)家族的结合位点。检测各组XBP1s和ITPR家族信使RNA(mRNA)和蛋白表达水平。结果 与AdshNC组比较,Ad-shNC+H/R组细胞凋亡水平更高,线粒体活性氧水平升高,线粒体膜电位降低,线粒体钙离子水平升高;与Ad-shNC+H/R组比较,Ad-shXBP1s+H/R组细胞凋亡水平较低,线粒体活性氧水平下降,线粒体膜电位升高,线粒体钙离子水平降低(均为P<0.05)。与Ad-shNC组比较,Ad-shXBP1s组XBP1s、ITPR1、ITPR2和ITPR3 mRNA和蛋白相对表达量降低(均为P<0.05)。与Ad-shNC组相比,Ad-shNC+H/R组XBP1s、ITPR1、ITPR2和ITPR3蛋白相对表达量升高;与Ad-shNC+H/R组相比,Ad-shXBP1s+H/R组XBP1s、ITPR1、ITPR2和ITPR3蛋白相对表达量下降(均为P<0.05)。ChIP-seq结果显示,XBP1s能够结合ITPR1的启动子和外显子、ITPR2外显子和ITPR3外显子。结论 XBP1s可能通过直接调控ITPR转录和翻译而影响线粒体相关的内质网膜结构功能,下调XBP1s能够抑制ITPR表达,改善线粒体损伤。

ERp44 C160S/C212S mutants regulate IP_(3)R_(1) channel activity

Previous studies have indicated that ERp44 inhibits inositol 1,4,5-trisphosphate(IP3)-induced Ca2+release(IICR)via IP3R1,but the mechanism remains largely unexplored.Using extracellular ATP to induce intracellular calcium transient as an IICR model,Ca2+image,pull down assay,and Western blotting experiments were carried out in the present study.We found that extracellular ATP induced calcium transient via IP3Rs(IICR)and the IICR were markedly decreased in ERp44 overexpressed Hela cells.The inhibitory effect of C160S/C212S but not C29S/T396A/ΔT(331–377)mutants of ERp44 on IICR were significantly decreased compared with ERp44.However,the binding capacity of ERp44 to L3V domain of IP3R1(1L3V)was enhanced by ERp44 C160S/C212S mutation.Taken together,these results suggest that the mutants of ERp44,C160/C212,can more tightly bind to IP3R1 but exhibit a weak inhibition of IP3R1 channel activity in Hela cells.

IP3R1调控CaMKⅡ和VDAC1在海洛因致心肌细胞节律异常中的作用

目的:探讨1,4,5-三磷酸肌醇1型受体(inositol 1,4,5-trisphosphate receptor type 1,IP3R1)调控钙/钙调蛋白依赖性蛋白激酶Ⅱ(calcium/calmodulin-dependent protein kinaseⅡ,CaMKⅡ)和电压依赖性阴离子通道1(voltage-dependent anion channel 1,VDAC1)在海洛因(heroin,HE)致心肌细胞节律异常中的作用。方法:联合蛋白组学和GEO(Gene Expression Omnibus)数据库分析心律失常芯片数据,寻找关键调控因子。构建IP3R1基因敲减慢病毒并感染原代乳大鼠心肌细胞(neonatal rat cardiomyocytes,NRCMs),实验分为对照(control)组、HE组和HE+shIP3R1组。结晶紫染色观察心肌细胞形态;ELISA法检测乳酸脱氢酶(lactate dehydrogenase,LDH)和天冬氨酸转氨酶(aspartate aminotransferase,AST)水平;透射电镜观察线粒体形态学变化;Fluo-4/AM探针法检测细胞内Ca^(2+)浓度;DCFH-DA荧光探针检测细胞内活性氧(reactive oxygen species,ROS)含量;JC-1染色法检测线粒体膜电位(mitochondrial membrane potential,MMP)水平;ATP检测试剂盒检测细胞内ATP水平;免疫共沉淀(co-immunopre-cipitation,Co-IP)分析IP3R1与CaMKⅡδ和VDAC1蛋白之间的相互作用;Western blot检测IP3R1、CaMKⅡδ、p-CaM-KⅡδ(T287)和VDAC1的蛋白水平。结果:结合蛋白质组学和基因表达谱数据集GSE89410分析,筛选得到80个差异共表达分子,基于基因本体论(Gene Ontology,GO)功能注释和京都基因与基因组百科全书(Kyoto Encyclopedia of Genes and Genomes,KEGG)富集分析结果,最终筛选出关键因子IP3R1,且通过STRING数据库获得IP3R1结合蛋白:CaMKⅡδ和VDAC1。Co-IP结果验证IP3R1与CaMKⅡδ和VDAC1存在相互作用,且HE干预后NRCMs中IP3R1与CaMKⅡδ和VDAC1之间的相互作用增强。体外细胞实验显示,与control组相比,HE组NRCMs数量急剧减少,细胞膜变窄,伪足减少,细胞核结构模糊;LDH和AST水平均显著上升(P<0.05);线粒体超微结构损伤严重,证实HE对NRCMs具有毒性作用并导致线粒体损伤。与control组相比,HE组心肌细胞内Ca^(2+)浓度、ROS水平、MMP以及IP3R1、p-CaMKⅡδ(T287)和VDAC1蛋白水平均显著升高(P<0.05),而HE+shIP3R1组这些指标均显著减低(P<0.05);ATP水平则相反。这证实沉默IP3R1表达可减轻HE干预后NRCMs的钙超载及线粒体损伤。结论:IP3R1通过调控CaMKⅡ和VDAC1引起心肌细胞钙超载和ROS生成增多,参与HE诱导的心肌细胞节律异常。

IP_3R1在弥漫性轴索损伤后早期的表达及其意义

目的通过观察大鼠弥漫性轴索损伤（diffuse axonal injury,DAI）后I型1,4,5-三磷酸肌醇受体（inositol 1,4,5-trisphosphate receptor type I,IP3R1）表达随时间的变化,探讨其作用,为DAI后轴索的继发性损伤及断裂提供研究基础。方法 25只健康雄性成年SD大鼠,随机分为对照组和实验组（DAI组）,采用Golgi镀银染色及SP免疫组织化学染色,观察其在不同时间（3~72h）的脑干组织病理变化及IP3R1的表达情况。结果 Golgi镀银染色证明大鼠DAI模型成功;免疫组织化学染色显示,对照组大鼠脑干中IP3R1有弱阳性表达,实验组阳性细胞较对照组明显增高,在DAI损伤后,大鼠脑干组织IP3R1表达3h时就开始升高,至24h高峰后开始下降,72h下降至低水平。结论IP3R1可能在DAI后轴索的继发性损伤及断裂中起重要作用。

内皮素1对胞浆Ca^(2+)升高调控作用的研究进展

由21个氨基酸残基组成的内皮素1(ET-1)不仅是已知最强的缩血管活性肽,还对血管形成与重构、细胞增殖、细胞外基质合成和感觉神经活化等诸多生理活动具有调控作用。其生理效应多通过升高胞浆Ca2+继而促发连锁反应来实现。增强细胞外Ca2+内流和促进胞内Ca2+释放是ET-1升高胞浆Ca2+浓度的两条基本途径,同时,通过抑制胞内的Ca2+外排与重摄取及对细胞核等非典型Ca2+库内的Ca2+信号的调控同样可以达到升高胞浆Ca2+浓度的目的,本文主要就ET-1升高胞浆Ca2+的调控途径作一综述。