Role of Angiotensin II in Hypertension-Induced Cardiac Hypertrophy and Failure

Besides playing a role in blood-pressure regulation and salt and fluid homeostasis, the octapeptide angiotensin II mediates cell growth and differentiation. Its effects are dependent on angiotensin receptors, of which both AT1 and AT2 receptors are extensively described. In cardiac hypertrophy and heart failure, angiotensin receptors are differentially regulated. It is established that AT1 receptors induce cell growth, while AT2 receptors have been associated with growth inhibition, differentiation, and apoptosis. The availability of receptors controlling cell function within a broad spectrum for a single hormone and the regulation of these receptors during cardiac hypertrophy and failure emphasize a complex role for angiotensin II in cardiac pathogenesis. Due to their functional properties, AT1 and AT2 receptors might counteract each other in cell growth processes. Therefore, the current clinical use of specific AT1 receptor antagonists raises questions as to the role of the AT2 receptor in disease processes such as cardiac hypertrophy and failure. Under AT1 receptor antagonist treatment, AT2 receptors are overexposed to angiotensin II. This article describes a possible role of angiotensin II through its angiotensin receptors AT1 and AT2 in cardiac hypertrophy and heart failure.     

Relevance of Angiotensin II for Cardiac Hypertrophy and Failure Induced by Cardiac Volume Overload

Angiotensin II can contribute to the development and maintenance of cardiac hypertrophy indirectly via its hemodynamic effects and directly via its cardiac trophic effects. Cardiac volume overload by aortocaval shunt increases plasma angiotensin II as well as angiotensin II generated by cardiac tissue. Plasma angiotensin II contributes to the cardiac volume overload via its hemodynamic effects, since blockers of the renin–angiotensin system attenuate the rise in left ventricular end-diastolic pressure (LVEDP). Increased cardiac angiotensin II, generated by and dependent on cardiac ACE, however, appears to drive the hypertrophic response. For a similar prevention of the rise in circulating angiotensin II and in LVEDP, only an angiotensin-converting enzyme (ACE) inhibitor with high affinity for cardiac ACE (quinapril) also prevents the rise in cardiac angiotensin II and—similar to an AT1 receptor blocker—the development of cardiac hypertrophy. An ACE inhibitor with low affinity for cardiac ACE (enalapril) does not prevent the rise in cardiac angiotensin II by aortocaval shunt and the development of cardiac hypertrophy. In the maintenance phase of cardiac volume overload, cardiac angiotensin II returns to normal and hypertrophic growth and cardiac remodeling cease. In this phase, enalapril causes regression of cardiac hypertrophy in relation to its hemodynamic effects and in a manner similar to an AT1 receptor blocker.In other models of cardiac volume overload (e.g., aortic insufficiency or minoxidil treatment), data on plasma and cardiac angiotensin II are missing, and the role of cardiac angiotensin II in the development and maintenance of cardiac hypertrophy is still to be assessed. Similarly, the role of cardiac angiotensin II in the transition from maintenance phase into heart failure and the progression of heart failure has not yet been studied.     

Effects of Olmesartan, an Angiotensin II Receptor Blocker, on Mechanically-Modulated Genes in Cardiac Myocytes

Background: Angiotensin II plays an important role in cardiac hypertrophy or remodeling. Angiotensin II receptor blockers (ARB) are clinically useful for the treatment of hypertension and heart failure. However, the molecular effects of ARB in the mechanically-stressed myocardium have not been completely defined. We investigated the effects of ARB on mechanically-modulated genes in cardiac myocytes. Methods: We used powerful DNA microarray technology to study the effects of the ARB, CS-886 (olmesartan), on genes modulated in neonatal rat cardiac myocytes using mechanical stimuli. Mechanical deformation was applied to a thin and transparent membrane on which neonatal rat cardiac myocytes were cultured in the presence or absence of RNH-6270, an active metabolite of CS-886. Expression profiles of 8000 rat genes using the Affymetrix GeneChip (Rat Genome U34A) were investigated with mRNA obtained from the samples above. Results: Nine genes induced under 4% mechanical strain were significantly suppressed by RNH-6270 in rat cardiac myocytes: monoamine oxidase B, neuromedine B receptor, olfactory receptor, synaptotagmin XI, retinol-binding protein, and 4 expressed sequence tags (ESTs). In contrast, 21 genes suppressed under mechanical strain were significantly restored by RNH-6270: major acute phase alpha 1-protein, Sp-1, Bcl-Xalpha, JAK2, 2 genes encoding detoxification, few genes for receptor, structure, metabolism or ion channel, and 10 ESTs. Conclusions: As some of these genes may be involved in promoting or modulating cardiac remodeling, these findings suggest that ARB may affect cardiovascular morbidity and mortality partially via these molecular alterations.     

Ca~(2+)-CaN-NFAT信号通路在心肌肥大中的作用及研究进展

钙调神经磷酸酶(calcineurin,CaN)是Ca2 的下游因子,在细胞内钙升高引起的心肌肥大中有重要作用。现综述Ca2 CaN及其下游因子活化T细胞核因子3(NFAT3)和锌指转录因子(GATA4)在心肌肥大中的作用及近年的研究进展。     

钙调神经磷酸酶在醛固酮诱导心肌肥大中的作用

目的观察钙调神经磷酸酶(CaN)在醛固酮(Ald)诱导的心肌肥大信号转导机制中的作用及其调节。方法24只Wistar大鼠随机分为2组:实验组和对照组。实验组给予醛固酮腹腔注射后,再随机分为3组,分别给予环孢霉素A、螺内酯、及生理盐水干预,对照组仅腹腔注射生理盐水。测定大鼠血浆中血管活性因子Ald、AngⅡ、ET1与NO-3的浓度,心重/体重,心肌组织中的CaN活性;心肌组织中肥大相关基因心房利钠因子(ANF)及CaNAβmRNA的水平,同时用免疫组化方法观察心肌胞浆中CaN的表达。结果醛固酮腹腔注射后血浆中的醛固酮水平明显增高,醛固酮腹腔注射4周可使心肌肥大相关基因ANFmRNA水平明显升高,心肌中CaN活性明显升高,心肌细胞浆中的CaN表达上调;环孢霉素A及螺内酯干预4周,可明显抑制心肌CaN活性,并下调ANF(P<0.05)的表达。结论CaN参与了外源性醛固酮诱导的心肌肥大的信号通路,醛固酮通过活化CaN,使肥大相关基因表达增加产生心肌肥大。螺内酯通过拮抗醛固酮与受体结合抑制心肌肥大。     

Effect of Losartan on Right Ventricular Hypertrophy and Cardiac Angiotensin I-Converting Enzyme Activity in Pulmonary Hypertensive Rats

The aim of this study was to investigate the effect of prophylactic treatment with the angiotensin type 1 (AT₁) receptor antagonist losartan on right ventricularhypertrophy and cardiac angiotensin I-converting enzyme (ACE) activity in a rat model of monocrotaline-induced pulmonary hypertension. Losartan failed to prevent either pulmonary hypertension or right ventricular hypertrophy. Right ventricular ACE in untreated pulmonary hypertensive rats did not differ from control rats. Losartan treatment in pulmonary hypertensive rats caused a significant 2-fold increase of ACE activity in the hypertrophied right (p<0.005) but not in the left ventricle. Thus, cardiac ACE activity is not stimulated in rats with monocrotaline-induced right ventricular hypertrophy. Prophylactic losartan treatment in this model of progressive pulmonary hypertension failed to prevent or reduce the increase in ventricular afterload. The relevance of the increase in right ventricular ACE activity during pulmonary hypertension after losartan treatment is unknown and needs to be evaluated in further studies.     

血管紧张素受体拮抗剂对SHR左室肥厚的影响

目的探讨血管紧张素Ⅱ受体（ＡＴＲ）拮抗剂在左室肥厚中的作用。方法自发性高血压大鼠（ＳＨＲ）分别接受ＴＣＶ－１１６（血管紧张素Ⅱ－１受体拮抗剂）、德那脯利（Ｄｅｌａｐｒｉｌ）及ＰＤ１２３３１９（血管紧张素Ⅱ－２受体拮抗剂）治疗３周,ＷＫＹ大鼠分别接受ＴＣＶ－１１６、Ｄｅｌａｐｒｉｌ治疗３周,分别与对照组比较收缩压及左室重量与体重比（ＬＶＷ／ＢＷ）。结果ＳＨＲ实验组：口服ＴＣＶ－１１６和Ｄｅｌａｐｒｉｌ分别使收缩压下降１８．５％和１９．０％,使ＬＶＷ／ＢＷ下降７．６％和８．３％;皮下注射ＰＤ１２３３１９对收缩压及ＬＶＷ／ＢＷ均无影响。ＷＫＹ实验组：口服ＴＣＶ－１１６和Ｄｅｌａｐｒｉｌ分别使收缩压下降１１．８％和１１．１％,对ＬＶＷ／ＢＷ无影响。结论血管紧张素Ⅱ－１型受体拮抗剂ＴＣＶ－１１６能逆转ＳＨＲ左室肥厚;血管紧张素Ⅱ－２型受体拮抗剂ＰＤ１２３３１９对ＳＨＲ左室肥厚无逆转作用。     

Stat 3--参与心肌肥大的一个新的信号转导及转录激活因子

信号转导及转录激活因子 3是细胞浆内的一种潜在的核转录因子 ,参与多种促心肌肥大因素的信号转导 ,并与心肌局部肾素血管紧张素系统相关联 ,本文对信号转导及转录激活因子 3在心肌肥大的发生发展中的作用作一综述。     

Signaling Pathways Involved in Cardiac Hypertrophy

Cardiac hypertrophy is the heart's response to a variety of extrinsic and intrinsic stimuli that impose increased biomechanical stress. Traditionally, it has been considered a beneficial mechanism; however, sustained hypertrophy has been associated with a significant increase in the risk of cardiovascular disease and mortality. Delineating intracellular signaling pathways involved in the different aspects of cardiac hypertrophy will permit future improvements in potential targets for therapeutic intervention. Generally, there are two types of cardiac hypertrophies, adaptive hypertrophy, including eutrophy (normal growth) and physiological hypertrophy (growth induced by physical conditioning), and maladaptive hypertrophy, including pathologic or reactive hypertrophy (growth induced by pathologic stimuli) and hypertrophic growth caused by genetic mutations affecting sarcomeric or cytoskeletal proteins. Accumulating observations from animal models and human patients have identified a number of intracellular signaling pathways that characterized as important transducers of the hypertrophic response, including calcineurin/nuclear factor of activated T- cells, phosphoinositide 3-kinases/Akt (PI3Ks/Akt) , G protein-coupled receptors, small G proteins, MAPK, PKCs, Gpl30/STAT3, Na /H exchanger, peroxisome proliferator-activated receptors, myocyte enhancer factor 2/histone deacetylases, and many others. Furthermore, recent evidence suggests that adaptive cardiac hypertrophy is regulated in large part by the growth hormone/insulin-like growth factors axis via signaling through the PI3K/Akt pathway. In contrast, pathological or reactive hypertrophy is triggered by autocrine and paracrine neurohormonal factors released during biomechanical stress that signal through the Gq/phosphorlipase C pathway, leading to an increase in cytosolic calcium and activation of PKC.     

Role of Endogenous Angiotensin II and Prostaglandins in the Antihypertensive Mechanism of Angiotensin Converting Enzyme Inhibitor in Hypertension

The role of endogenous angiotensin II and prostaglandins (PGs) in the antihypertensive effect of converting enzyme inhibitor, captopril, was studied in essential hypertension by the separate and the combined administration of captopril and indomethacin. Although plasma angiotensin II was similarly suppressed by the separate and the combined administration of captopril and indomethacin, captopril lowered and indomethacin increased the mean blood pressure. There were negative correlations between the changes in mean blood pressure and in urinary sodium excretion as well as in urinary PGE excretion. These results suggest that endogenous PGs may be implicated in the antihypertensive effect of captopril through the alteration of sodium balance.     

心肌肥厚和扩张型心肌病中的Notch信号通路

Notch信号通路在脊椎动物和无脊椎动物中高度保守。它对正常心血管系统的发育有重要作用。心肌肥厚是许多疾病发展的一个重要阶段,但是它的形成机制到现在还没有完全清楚。扩张型心肌病是一组由于基因缺陷、心肌细胞损伤、心肌组织浸润使心脏肌肉层直接受累的疾病,其临床表现主要为心脏增大、心律失常,最终发生心力衰竭。最近的研究揭示Notch很可能在在这些疾病进程中起到非常关键的保护作用。     

Effects of Angiotensin II on Expression of the Gap Junction Channel Protein Connexin 43 in Neonatal Rat Ventricular Myocytes

Objectives To study the effects of angiotensin II, as a mediator of cardiac hypertrophy, on expression of connexin 43 (Cx43) in cultured neonatal rat ventricular myocytes and correlation of expression of Cx43 and cardiomyocyte hypertrophy. Methods Cardiomyocytes were isolated from newborn SD rats. Angiotensin II was added into the media to induce myocyte hypertrophy. Cultures were exposed to 10～6 mol/L angiotensin II for 72 h, Cx43 expression was characterized by RT-PCR and Immunofluorescence methods. Results Immunofluorescence analysis revealed decreased Cx43 immunoreactivity in cells treated for 72 h with angiotensin II. RT-PCR analysis demonstrated there was an obvious decrease of Cx43 mRNA level in cells exposed to angiotensin II for 72 h. The changes of expression of connexin 43 were related to its entrance into S phase of the cell cycle. Cultured neonatal rat cardiomyocytes were exposed for 72 h to increase concentrations of angiotensin II (1.0×10-9～1.0×10-6mol/L), resulting in significantly decreased Cx43 expression. Conclusions Angiotensin II leads to a concentration-dependent decrease in Cx43 protein in cultured neonatal rat ventricular myocytes by decreasing Cx43 mRNA synthesis. Signal transduction pathways activated by angiotensin II under pathophysiologic conditions of cardiac hypertrophy could initiate remodeling of gap junctions.     

Angiotensin II receptor blocker attenuates stress pressor response in young adult African Americans

African Americans (AAs) are susceptible to hypertension (HTN) and its associated organ damage leading to adverse cardiovascular (CV) outcomes. Psychological stress is proposed to contribute to the development of HTN; however, the potential role of the renin‐angiotensin system (RAS) in stress‐related HTN in AAs is largely unknown. In this study, we tested the hypothesis that activation of RAS is a potential contributing factor for altered CV responses to stress, and suppression of angiotensin II (Ang II) activity will improve hemodynamic responses to a prolonged mental stressor in healthy young AAs. Utilizing a double‐blind, randomized, crossover study design, 132 normotensive AAs (25 ± 7 years) were treated with either a placebo (PLC) or 150 mg/d irbesartan (an Ang II type 1 receptor blocker; ARB) for 1 week. On the final day of each treatment, hemodynamic measures and urinary sodium excretion (UNaV) were collected before, during and after a 45 minute‐mental stress. The magnitude of stress‐induced increase in blood pressure with ARB was blunted and delayed compared to PLC. Systolic blood pressure at the end of recovery on ARB was significantly lower compared to either PLC (110 ± 13 vs 117 ± 12 mm Hg respectively; P < 0.001) or the prestress level on ARB (P = 0.02). ARB treatment reduced overall vasoconstriction and improved poststress UNaV. ARB attenuated blood pressure responses to mental stress and improved the poststress BP recovery process which were partly linked to reduced overall vasoconstriction and improved stress‐induced UNaV in young adult AAs prior to the development of disease conditions. These results suggest that treatment approaches that inhibit RAS action could have significant relevance to potentially lower susceptibility to stress responses and eventually the premature development of HTN in AAs.     

Human Angiotensin II Receptors are Regulated By Angiotensin II

Specific angiotensin II (ANG II) binding on human platelets in man was measured to examine ANG II receptor regulation in man. Eight normal volunteers received either a high, or a low sodium diet, or a low sodium diet together with the ANG I converting enzyme inhibitor enalapril. The following parameters were determined at the end of each study period: ANG II platelet receptor binding capacity (B_max) and dissociation constant (K_D); plasma-ANG II, plasma renin, plasma-aldosterone, plasma-atrial natriuretic peptide; and blood pressure (BP) increase to graded doses of i.v. given ANG II. Plasma ANG II (6±0.5, 21±4, 8±1 fmol/ml) and B_max (14±2, 5±1, 10±2 sites/cell) changed in a reciprocal fashion on a high, low or low sodium diet with enalapril respectively. Plasma concentration of atrial natriuretic peptide was unchanged on a low sodium intake and consistently decreased when enalapril was added to the low sodium regimen. BP increase to 4 ng ANG II/kg/min was 27±3, 10±1, and 24±5 mmHg during the three study periods respectively. The data suggest that ANG II regulates maximal capacity of platelet ANG II binding. Therefore, regulation of platelet ANG II binding sites goes in parallel with, and may serve as index for, ANG II receptors on vascular smooth muscle, but ANG II receptor regulation is apparently different in adrenal cells.     

Mechanisms Involved in Angiotensin II Induced Increases in Cardiac Output in Pithed Rats

This study was conducted to determine the mechanisms by which angiotensin II (Ang-II) acutely increases cardiac output. Pithed Sprague-Dawley rats were prepared for continuous measurement of cardiac output by electromagnetic flowmetry. Ang-II (31 – 1000 ng/kg, i.v.) produced dose-related increases in cardiac output, heart rate and stroke volume. Although the heart rate increases were abolished by beta-adrenoceptor blockade, the cardiac output responses were unchanged due to an offsetting increase in stroke volume. The constancy of the cardiac output response following beta-adrenoceptor blockade suggested that Ang-II increased cardiac output by constricting venous smooth muscle and thereby increasing venous return. This conclusion is supported by the observation that Ang- I I produced marked increases in 1 eft ventri cul ar end diastolic pressure that paralleled the increases in cardiac output. In fact, based on volume loading with Tyrode's solution, the changes in left ventricular end diastolic pressure produced by Ang-I1 should have resulted in even greater increases in cardiac output. However, it appears that the significant rise in peripheral resistance to Ang-cardiac output. In addition, the Ang-II-induced elevations in II tended to counter the effects of increased venous return on cardiac output. In addition, the Ang-II-induced elevations in cardiac output were not altered by alpha-adrenoceptor blockade. Therefore, catecholamines do not play a role in mediating the Ang-II effects. The results of this study support the conclusion that Ang-II is capable of increasing cardiac output by constriction of venous smooth muscle.     

Apelin对血管紧张素Ⅱ诱导的心肌细胞肥大的作用及其机制

目的：探讨Apelin对血管紧张素Ⅱ（AngⅡ）诱导的心肌细胞肥大的作用及其细胞内信号转导机制。
　　方法：培养1~3 d新生Sprague-Dawley大鼠心肌细胞,给予AngⅡ刺激。在此基础上给予不同浓度Apelin。测定[3H]亮氨酸掺入量、细胞表面积以及总蛋白表达量评价心肌细胞肥大程度。免疫印迹法测定细胞B型尿钠肽、β肌球蛋白重链、活化T细胞的核因子3、钙调神经磷酸酶、磷酸化钙调神经磷酸酶、钙调蛋白激酶Ⅱ、磷酸化钙调蛋白激酶Ⅱ的蛋白表达水平。逆转录-聚合酶链反应法测定B型尿钠肽和β肌球蛋白重链mRNA表达水平。
　　结果：Apelin可以抑制AngⅡ诱导的心肌细胞肥大,其作用呈剂量依赖性。同时,Apelin可以抑制AngⅡ诱导的B型尿钠肽和β肌球蛋白重链mRNA表达水平、B型尿钠肽和β肌球蛋白重链、活化T细胞的核因子3、磷酸化钙调神经磷酸酶、钙调蛋白激酶Ⅱ和磷酸化钙调蛋白激酶Ⅱ的蛋白表达水平升高,且均与Apelin浓度呈剂量依赖性。
　　结论：Apelin可以抑制AngⅡ诱导的心肌细胞肥大,其机制与Ca2+依赖的钙调神经磷酸酶信号转导通路有关。     

短时快速激动对肥厚心肌电生理特性的影响及其与室性心律失常的关系

观察短时快速激动对肥厚心肌电生理特性的影响并探讨其与室性心律失常 (VA)发生的关系。以部分结扎腹主动脉方法制作心肌肥厚模型。阻滞自主神经后 ,在心外膜右室流出道 (RVOT)、右室心尖部 (RVA)、左室流出道(LVOT)及左室心尖部 (LVA)四个部位以 2 2 0 ,2 4 0 ,2 6 0次 /分的频率刺激测定各部位的单相动作电位时限 (MAPD)及有效不应期 (ERP)。然后于 1∶1房室传导下 ,随机进入普通右房电刺激组 (2 2 0次 /分 )和快速右房电刺激组 (2 6 0次 /分 ) ,持续 30min后 ,重复上述测定过程。记录心室后除极的发生次数。最后诱发心室颤动 (VF) ,记录诱发率和VF持续时间。结果 :心肌肥厚组快速激动后除RVA外 ,其他各部位的ERP值均显著延长 (2 2 0 ,2 4 0 ,2 6 0次 /分频率刺激下的前后ERP值 (ms)为 :RVOT 15 1± 18vs181± 2 1,14 5± 17vs173± 14 ,14 0± 15vs 16 7± 14 ;RVA 16 1± 17vs 171± 19,15 5± 16vs 16 6± 19,15 2± 17vs 16 2± 18;LVOT 16 5± 2 7vs192± 2 0 ,16 1± 2 5vs187± 2 1,15 4± 17vs178± 15 ;LVA 170±15vs191± 15 ,16 5± 15vs189± 11,15 9± 13vs 182± 11)。而对照组在快速激动后的ERP延长并不显著。心肌肥厚组和对照组在普通刺激下 ,ERP均无明显延长。各组在刺激前后的MAPD?     

Cardiac Baroreflex in Hypertension: Role of the Heart and Angiotensin II

Sigmoid logistic function curves provide a powerful means of characterizing the baroreceptor-heart rate reflex. In hypertension the operating range of the reflex is reset in the direction of the elevated resting BP; this can be accounted by rapid resetting of the threshold of the arterial baroreceptors. In addition, there is a deficit in the vagal component of the heart rate (HR) range. Reduction in gain occurs in moderate/severe hypertension, but may be absent in young primary hypertensives. All the changes are reversible, and reversibility of HR range and gain is related to reducing left ventricular hypertrophy or central blood volume rather than to reduction in BP. High plasma angiotensin II can further accentuate the vagal deficit. An input-output model has been developed from comparison of perivascular cuff and drug methods for eliciting the reflex, which place different loads on the heart; the greater load changes simulate many of the alterations in reflex properties observed in hypertension. We conclude that during changes in vasomotor tone in normal animals, about 70% of the drive for the cardiac baroreflex comes from arterial baroreceptors and about 30% from low threshold cardio-pulmonary baroreceptors. In hypertension, the vagal deficit in HR range is due to afferent interactions involving arterial and low and high threshold cardio-pulmonary baroreceptors.     

血管紧张素转换酶基因型与高血压左室肥厚的相关性研究

目的研究血管紧张素转换酶（ＡＣＥ）基因型与高血压患者左室肥厚的关系。方法用ＰＣＲ方法分别检测１５１例原发高血压患者ＡＣＥ基因型,并做超声心动图检查,测量左室舒张末径（ＤＬＶｄ）、左室收缩末径（ＳＬＶｄ）、心脏室间隔厚度（ＩＶＳ）及左室后壁厚度（ＬＶＰＷ）,计算左室重量（ＬＶＭ）。结果各基因型组中ＤＤ型的ＤＬＶｄ、ＳＬＶｄ、ＩＶＳ、ＬＶＰＷ、ＬＶＭ分别为４９．９±５．６ｍｍ、３０．５±６．５ｍｍ、１１．２±１．６ｍｍ、１１．７±１．５ｍｍ、２５９．５±６２．１ｇ,ＩＤ型组的ＤＬＶｄ、ＳＬＶｄ、ＩＶＳ、ＬＶＰＷ、ＬＶＭ分别为４８．９±５．３ｍｍ、３１．５±５．２ｍｍ、１１．４±１．７ｍｍ、１１．９±１．６ｍｍ、２６１．３±７０．３ｇ,Ｉ型组的ＤＬＶｄ、ＳＬＶｄ、ＩＶＳ、ＬＶＰＷ、ＬＶＭ分别为４８．９±５．５ｍｍ、３１．８±６．５ｍｍ、１１．１±１．９ｍｍ、１１．５±１．８ｍｍ、２５０．８±８２．５ｇ,各基因型组间ＤＬＶｄ、ＳＬＶｄ、ＩＶＳ、ＬＶＰＷ、ＬＶＭ并无显著性差异（Ｐ＞０．０５）。结论国人ＡＣＥ基因型与高血压左室肥厚无关。     

肌侵蛋白起始心脏肥厚机制的研究进展

肌侵蛋白是12kDa的锚蛋白重复序列(ANK)蛋白,是最小的(ANK)2重复蛋白,ANK结构域使其能介导蛋白之间以及蛋白与核酸之间的相互作用。肌侵蛋白在哺乳动物的组织中广泛表达并能刺激心肌细胞的生长和心肌蛋白的合成。它最初是在肥厚和患有心肌病的心脏中被鉴定,起始心脏肥厚的过程,并最终导致心力衰竭(心衰)。近来的研究表明核转录因子-kappaB(NF-κB)参与心脏重塑和心衰的病理过程,而肌侵蛋白通过与NF-κB蛋白相互作用活化NF-κB信号途径激活心脏肥厚基因的表达。