Cardiac metabolism,inflammation, and peroxisome proliferator-activated receptors modulated by 1,25-dihydroxyvitamin D3 in diabetic rats

Background

High free fatty acid with reduced glucose utilization in diabetes mellitus (DM) impairs cardiac function. Peroxisome proliferator-activated receptors (PPARs) modulate myocardial lipid and glucose homeostasis. The active 1,25-dihydroxyvitamin D₃ (1,25(OH)₂D₃) regulates oxidative stress and inflammation, which may play a key role in the modulation of PPARs. The aim of this study was to investigate whether 1,25(OH)₂D₃ can modulate the cardiac PPARs and fatty acid metabolism.

Methods

Electrocardiogram, echocardiogram, and Western blot analysis were used to evaluate cardiac fatty acid metabolism, inflammation, and PPAR isoform expression in Wistar-Kyoto (WKY) rats, DM rats, and DM rats treated with 1,25(OH)₂D₃.

Results

Compared to healthy rats, DM and 1,25(OH)₂D₃-treated DM rats had lower body weight. DM rats had larger left ventricular end-diastolic diameter, and longer QT interval than healthy or 1,25(OH)₂D₃-treated DM rats. Moreover, compared to healthy or 1,25(OH)₂D₃-treated DM rats, DM rats had fewer cardiac PPAR-α and PPAR-δ protein expressions, but had increased cardiac PPAR-γ protein levels, tumor necrosis factor-α, interleukin-6, 5′ adenosine monophosphate-activated protein kinaseα2, phosphorylated acetyl CoA carboxylase, carnitine palmitoyltransferase 1, PPAR-γ coactivator 1-α, cluster of differentiation 36, and diacylglycerol acyltransferase 2 protein expressions.

Conclusions

1,25(OH)₂D₃ significantly changed the cardiac function and fatty acid regulations in DM hearts, which may be caused by its regulations on cardiac PPARs and proinflammatory cytokines.     

microRNA-33通过调节巨噬细胞自噬 干预心肌细胞胆固醇代谢受损和功能缺陷

目的 探讨microRNA-33通过调节巨噬细胞自噬对心肌细胞胆固醇代谢受损和功能缺陷的影响.方法 分别培养人单核巨噬细胞和人心肌细胞后将实验分为对照组、miR-33模拟物组(10、5.0、1.0μmol/L组)和miR-33抑制剂组(10、5.0、1.0μmol/L组).分别测定各组巨噬细胞存活率和自噬相关蛋白表达水...     

Recombinant adeno-associated virus serotype 9 with p65 ribozyme protects H9c2 cells from oxidative stress through inhibiting NF-κB signaling pathway

Background Oxidative stress is a major mechanism underlying the pathogenesis of cardiovascular disease. It can trigger inflammatory cascades which are primarily mediated via nuclear factor-κB (NF-κB). ...     

miR-139-3p在低氧诱导凋亡的心肌细胞中的表达及其作用研究

目的:探讨微小RNA-139-3p(miR-139-3p)在低氧诱导的原代心肌细胞凋亡模型中的表达及其意义。方法:在正常和低氧条件下,采用RT-qPCR检测乳大鼠原代心肌细胞miR-139-3p的表达水平;进一步将miR-139-3p抑制剂和miR-139-3p抑制剂阴性对照转染到心肌细胞后,将细胞置于37℃密闭的缺氧盒中(95%N_2和5%CO_2)培养12 h,采用流式细胞术和Western blot法检测细胞凋亡情况。结果:低氧培养12 h后,与正常培养组(n=3)比较,低氧组(n=3)心肌细胞中的miR-139-3p相对表达量显著上调(P0.05)。低氧组心肌细胞凋亡率也显著升高(P0.05)。与miR-139-3p抑制剂阴性对照组(n=3)比较,miR-139-3p抑制剂组(n=3)的心肌细胞凋亡率显著降低(P0.05)。结论:miR-139-3p在低氧诱导的原代心肌细胞凋亡模型中表达上调。抑制miR-139-3p的表达能降低低氧诱导的心肌细胞凋亡。     

The extracellular matrix: At the center of it all

The extracellular matrix is not only a scaffold that provides support for cells, but it is also involved in cell-cell interactions, proliferation and migration. The intricate relationships among the cellular and acellular components of the heart drive proper heart development, homeostasis and recovery following pathological injury. Cardiac myocytes, fibroblasts and endothelial cells differentially express and respond to particular extracellular matrix factors that contribute to cell communication and overall cardiac function. In addition, turnover and synthesis of ECM components play an important role in cardiac function. Therefore, a better understanding of these factors and their regulation would lend insight into cardiac development and pathology, and would open doors to novel targeted pharmacologic therapies. This review highlights the importance of contributions of particular cardiac cell populations and extracellular matrix factors that are critical to the development and regulation of heart function.     

MR-1通过抑制PERK/Nrf2途径减轻缺氧/复氧诱导的心肌细胞凋亡

 目的:研究肌原纤维形成调节因子1 (MR-1)是否通过抑制蛋白激酶R样内质网激酶 (PERK)/核因子E2相关因子2（Nrf2）途径减轻缺氧/复氧 (H/R)诱导的心肌细胞凋亡。方法:在原代培养的乳大鼠心肌细胞H/R模型上,采用Annexin V/PI双标法检测心肌细胞的凋亡率;以Western blotting检测葡萄糖调节蛋白78 (GRP78)、磷酸化PERK、Nrf2、活化转录因子4 (ATF4)、C/EBP同源蛋白 (CHOP)、Bcl-2和Bax的蛋白水平,研究过表达或敲低对于H/R致心肌细胞凋亡的影响及其与PERK/Nrf2途径活化的关系。结果:H/R引起心肌细胞凋亡;过表达MR-1减轻H/R引起的细胞凋亡 (P<0.01),下调CHOP表达 (P<0.05),引起Bcl-2/Bax值升高 (P<0.01),并抑制H/R诱导的PERK磷酸化、Nrf2核转位和ATF4表达 (P<0.01)。敲低MR-1加重H/R引起的细胞凋亡 (P<0.01)、CHOP表达上调 (P<0.05)和Bcl-2/Bax值下降 (P<0.01),并加重H/R诱导的PERK磷酸化 (P<0.05)、Nrf2核转位和ATF4表达 (P<0.01)。结论:MR-1通过抑制PERK/Nrf2途径而减轻缺氧/复氧诱导的心肌细胞凋亡。     

番茄红素对缺氧/复氧诱导小鼠心肌细胞内质网应激和凋亡的影响

目的 评价番茄红素对缺氧/复氧(hypoxia/reoxygenation,H/R)引起的小鼠心肌细胞内质网应激(endoplasmic reticulum stress,ERS)和凋亡的影响. 方法 建立C57BU6乳鼠心肌细胞H/R模型,采用随机数字表法将C57BL/6小鼠心肌细胞分为正常对照组(C组)、番茄红素组(Lyc组,含5μmol/L番茄红素的培养基预处理4h)、H/R组(H/R组,缺氧4h复氧6h)和番茄红素+H/R组(Lyc+H/R组,给予5μmol/L番茄红素预处理4h后行H/R处理).采用水溶性四氮唑-8(cell counting Kit-8,CCK-8)法检测心肌细胞存活率,倒置显微镜下观察细胞搏动频率,TUNEL法检测细胞凋亡率,二氯荧光素法(dichlomnuorescein diacetate,DCFH-DA)检测细胞内活性氧(reactive oxygen species,ROS)含量,实时荧光定量PCR (real-time PCR)检测葡萄糖调节蛋白78(glucose-regulated protein 78,GRP78)、C/EBP同源蛋白(C/EBP homologous protein,CHOP)及半胱天冬氨酸蛋白酶-12 (cysteme aspartate specific protease-12,caspase-12)mRNA的表达,Western blot法分析剪切的半胱天冬氨酸蛋白酶-12(cleaved cysteme aspartate specific protease-12,Cleaved-caspase-12)和剪切的半胱天冬氨酸蛋白酶-3(cleaved cysteme aspartate specific protease-3,Cleaved-caspase-3)的表达. 结果 与C组比较,H/R组心肌细胞存活率显著降低[(100±5)％,(69±6)％](P＜0.01),搏动频率显著降低[(94±6),(28±5)次/min](P＜0.01),心肌细胞凋亡率[(4.9±1.5)％,(25.6±2.6)％]和ROS含量[(100±11)％,(226±10)％]显著升高(P＜0.01);CHOP mRNA[(1.00±0.10)、(2.60±0.19)]和GRP78 mRNA[(1.00±).18)、(4.12±0.23)]表达水平显著升高(P＜0.05);caspase-12 mRNA[(1.00±0.09)、(1.79±0.14)]、Cleaved-caspase-12[(1.00±0.08)、(1.85±0.10)]和Cleaved-caspase-3[(1.00±0.07)、(1.89±0.14)]表达水平显著升高(P＜0.05).与H/R组比较,Lyc+H/R组心肌细胞存活率明显升高[(69±6)％、(84±7)％](P＜0.05),搏动频率增加[(28±5)、(73±6)次/min] (P＜0.05),凋亡率显著降低[(25.6±2.6)％,(18.2±2.2)％](P＜0.05),细胞内ROS含量[(226±10)％、(140±16)％]明显降低,CHOP mRNA [(2.60±0.19)、(1.71±0.14)]和GRP78 mRNA[(4.12±0.23),(1.98±0.19)]表达水平显著降低(P＜O.05);caspase-12 mRNA[(1.79±0.14)、(1.38±0.11)]、Cleaved-caspase-12[(1.85±0.10)、(1.26±0.12)]和Cleaved-caspase-3[(1.89±0.14)、(1.36±0.12)]表达水平显著降低(P＜0.05). 结论 番茄红素可抑制H/R过程中的ERS及其凋亡信号途径而减轻心肌细胞损伤.     

薯蓣皂苷对培养乳鼠心肌细胞缺氧／复氧损伤的保护作用

目的研究薯蓣皂苷对培养乳鼠心肌细胞缺氧／复氧损伤的保护作用并探讨其作用机制。方法采用体外培养乳鼠心肌细胞，建立缺氧／复氧损伤模型，以薯蓣皂苷进行干预。心肌细胞随机分为5组：空白对照组（C组）；缺氧／复氧组（A／R组）；薯蓣皂苷（Dioscin）低、中、高剂量干预组（Dioscin＋A／R组）。分别观察各组心肌细胞搏动频率；MTr法测细胞存活率；用Rhl23荧光探针标记线粒体，检测荧光强度以反映线粒体膜电位（△ψm）变化；Fluo-3负载心肌细胞，激光扫描共聚焦显微镜观察细胞内钙离子浓度变化。结果薯蓣皂苷干预组心肌细胞搏动频率、细胞存活率、△ψm与A／R组比较明显升高；细胞内平均钙离子荧光强度显著低于A／R组。结论从细胞水平初步证实薯蓣皂苷预处理心肌细胞对A／R损伤有一定保护作用，保护机制可能涉及对线粒体膜保护和防止细胞内钙超载等。     

心肌细胞裂解成分诱导骨髓间充质干细胞分化的超微结构观察

目的:观察骨髓间充质干细胞(MSCs)在心肌细胞裂解成分作用下超微结构改变,了解心肌细胞裂解成分对MSCs分化的诱导作用。 方法:分离并裂解新生大鼠的心肌细胞;自成年大鼠骨髓中分离MSCs;将分离的MSCs分3组培养:仅用普通培养基培养(对照组);5-氮杂胞苷(5-aza)诱导后用普通培养基培养(5-aza诱导组);含有心肌细胞裂解成分的培养基培养(心肌细胞裂解成分培养组)。培养1周,观察细胞形态及超微结构的改变,对培养的细胞进行抗心脏特异性肌钙蛋白T(cTnT)及抗分化决定簇31(CD31)细胞免疫化学染色,并分析各组细胞的增殖情况。 结果:对照组MSCs无明显的肌样细胞或内皮样细胞形成,抗cTnT和抗CD31染色阴性。5-aza诱导组部分MSCs分化为肌样细胞,电镜下可见大量细胞器空化,抗cTnT染色阳性,但细胞增殖缓慢。心肌细胞裂解成分培养组的MSCs分化为肌样细胞,电镜下可见肌丝样结构,抗cTnT染色阳性,细胞增殖旺盛,另见部分MSCs分化为内皮样细胞,形成内皮细胞特有的胞质突起和质膜小泡等超微结构,且抗CD31染色阳性。 结论:含有心肌细胞裂解成分的培养基可以诱导MSCs向心肌样细胞和内皮样细胞方向分化。