Pep 2-8, a linear peptide consisting of 13 amino acids, inhibits PCSK9 with a KD value of 0.7μM and suppresses the binding of LDL receptors and the EGF(A) domain to PCSK9, with IC50 values of 0.8 and 0.4μM, respectively [1]. Pep 2-8 neutralizes the activity of PCSK9, prevents the degradation of LDL receptors and restore the function of LDL receptors in cells[2]. Pep 2-8 has been widely used as a model compound to develop a series of derivatives for regulating the level of LDLR protein in cells [3].
In vitro, Pep 2-8 treatment for 24h (10µM) in the presence of lipopolysaccharide (20ng/mL;24h) significantly decreased phosphorylation of mTOR in vascular smooth muscle cells (VSMCs) and decreased apoptosis[4]. Pep 2-8 (10μM) pretreatment of VSMCs from obese insulin-resistant Zucker rats for 30 minutes can inhibit the expression of pERK-1/2 induced by a high glucose environment, and block the activation of the MAPK/ERK-1/2 pathway[5].
In vivo, Pep 2-8 treatment via subcutaneous injection (10µg/kg) once every two weeks for 10 weeks significantly inhibited the downregulation of NOX4, MAPK subunits, and NF-κB expression caused by PCSK9 in the aorta of mice, as well as the secretion of pro-inflammatory cytokines, preventing vascular aging[6]. A single intravenous injection of Pep 2-8 (10μg/kg) for 120 minutes reduced the myocardial infarction area in rats with ischemia/reperfusion injury, improved the mitochondrial function of the heart, and decreased the expression of apoptosis-related proteins[7]. Intravenous injection of Pep 2-8 (10µg per mouse/day) for one week improved the contractile function of the hearts of mice with left coronary artery (LCA) occlusion and inhibited the autophagic activity in ischemic hearts[8].
References:
[1] Zhang Y, Eigenbrot C, Zhou L, et al. Identification of a small peptide that inhibits PCSK9 protein binding to the low density lipoprotein receptor[J]. Journal of Biological Chemistry, 2014, 289(2): 942-955.
[2] Lammi C, Sgrignani J, Arnoldi A, et al. Biological characterization of computationally designed analogs of peptide TVFTSWEEYLDWV (Pep2-8) with increased PCSK9 antagonistic activity[J]. Scientific reports, 2019, 9(1): 2343.
[3] Tombling B J, Lammi C, Bollati C, et al. Increased valency improves inhibitory activity of peptides targeting proprotein convertase subtilisin/kexin type 9 (PCSK9)[J]. ChemBioChem, 2021, 22(12): 2154-2160.
[4] Ding Z, Liu S, Wang X, et al. Cross-talk between PCSK9 and damaged mtDNA in vascular smooth muscle cells: role in apoptosis[J]. Antioxidants & redox signaling, 2016, 25(18): 997-1008.
[5] Barale C, Tempesta G, Melchionda E, et al. PCSK9 Expression in Vascular Smooth Muscle Cells: Role of Insulin Resistance and High Glucose[J]. International Journal of Molecular Sciences, 2025, 26(3): 1003.
[6] Liu S, Wu J, Stolarz A, et al. PCSK9 attenuates efferocytosis in endothelial cells and promotes vascular aging[J]. Theranostics, 2023, 13(9): 2914.
[7] Palee S, McSweeney C M, Maneechote C, et al. PCSK9 inhibitor improves cardiac function and reduces infarct size in rats with ischaemia/reperfusion injury: Benefits beyond lipid‐lowering effects[J]. Journal of cellular and molecular medicine, 2019, 23(11): 7310-7319.
[8] Ding Z, Wang X, Liu S, et al. PCSK9 expression in the ischaemic heart and its relationship to infarct size, cardiac function, and development of autophagy[J]. Cardiovascular Research, 2018, 114(13): 1738-1751.
Pep 2-8是一种由13个氨基酸组成的线性肽，可抑制PCSK9活性（KD=0.7μM），并抑制LDL受体及EGF(A)结构域与PCSK9的结合，IC50值分别为0.8μM和0.4μM[1]。Pep 2-8通过中和PCSK9活性，阻止LDL受体降解并恢复细胞中LDL受体功能[2]。Pep 2-8已被广泛作为模型化合物用于开发调控细胞LDLR蛋白水平的一系列衍生物[3]。
在体外，在脂多糖（20ng/mL；24小时）存在下，10µM的Pep 2-8处理24小时可显著降低血管平滑肌细胞（VSMCs）中mTOR磷酸化水平并减少细胞凋亡[4]。10μM的Pep 2-8预处理来自肥胖胰岛素抵抗Zucker大鼠的VSMCs 30分钟，能抑制高糖环境诱导的pERK-1/2表达，并阻断MAPK/ERK-1/2通路激活[5]。
在体内，小鼠每两周皮下注射Pep 2-8（10µg/kg；持续10周）可显著抑制主动脉中PCSK9引起NOX4、MAPK亚基和NF-κB表达的下调，减少促炎细胞因子分泌，延缓血管老化[6]。大鼠单次静脉注射10μg/kg剂量的Pep 2-8（120分钟）能减少缺血/再灌注损伤后的心肌梗死面积，改善心脏线粒体功能并降低凋亡相关蛋白表达[7]。左冠状动脉结扎小鼠每日静脉注射10µg的Pep 2-8（持续一周）可改善心脏收缩功能，并抑制缺血心脏的自噬活性[8]。