Tasdemiroglu Yagmur, Council-Troche McAlister, Chen Miao, Ledford Benjamin, Norris Russell A, Poelzing Steven, Gourdie Robert G, He Jia-Qiang
Department of Biomedical Sciences and Pathobiology, College of Veterinary Medicine, Virginia Tech, 225 Duck Pond Drive, Blacksburg, Virginia 24061, United States.
Department of Medicine, Medical University of South Carolina, Charleston, South Carolina 29425, United States.
ACS Pharmacol Transl Sci. 2024 Apr 22;7(5):1624-1636. doi: 10.1021/acsptsci.4c00120. eCollection 2024 May 10.
In previous research, a synthetic α-carboxyl terminus 1 (αCT1) peptide derived from connexin 43 (Cx43) and its variant (αCT11) showed beneficial effects in an ischemia-reperfusion (I/R) heart injury model in mouse. In an mouse model of cryo-induced ventricular injury, αCT1 released from adhesive cardiac patches reduced Cx43 remodeling and arrhythmias, as well as maintained cardiac conduction. Whether intravenous injection of αCT1 or αCT11 produces similar outcomes has not been investigated. Given the possibility of peptide degradation in plasma, this study utilized I/R cardiac injury and blood plasma models to examine factors that may limit the therapeutic potential of peptide therapeutics . Following tail vein administration of αCT11 (100 μM) in blood, no effect on I/R infarct size was observed in adult rat hearts on day 1 (D1) and day 28 (D28) after injury ( > 0.05). There was also no difference in the echocardiographic ejection fraction (EF%) between the control and the αCT11 groups ( > 0.05). Surprisingly, αCT11 in blood plasma collected from these rats was undetectable within ∼10 min after tail vein injection. To investigate factors that may modulate αCT11 degradation in blood, αCT11 was directly added to blood plasma isolated from normal rats without I/R and peptide levels were measured under different experimental conditions. Consistent with observations, significant αCT11 degradation occurred in plasma within 10 min at 22 and 37 °C and was nearly undetectable by 30 min. These responses were reduced by the addition of protease/phosphatase (PTase/PPTase) inhibitors to the isolated plasma. Interestingly, no significant differences in αCT11 degradation in plasma were noted between male and female rats. We conclude that fast degradation of αCT11 is likely the reason that no beneficial effects were observed in the I/R model and inhibition or shielding from PTase/PPTase activity may be a strategy that will assist with the viability of peptide therapeutics.
在先前的研究中，一种源自连接蛋白43（Cx43）的合成α羧基末端1（αCT1）肽及其变体（αCT11）在小鼠缺血再灌注（I/R）心脏损伤模型中显示出有益效果。在冷冻诱导的心室损伤小鼠模型中，从粘附性心脏贴片释放的αCT1减少了Cx43重塑和心律失常，并维持了心脏传导。静脉注射αCT1或αCT11是否会产生类似结果尚未得到研究。鉴于肽在血浆中可能降解的可能性，本研究利用I/R心脏损伤和血浆模型来检查可能限制肽疗法治疗潜力的因素。在成年大鼠心脏损伤后第1天（D1）和第28天（D28），尾静脉注射αCT11（100μM）后，未观察到对I/R梗死面积有影响（>0.05）。对照组和αCT11组之间的超声心动图射血分数（EF%）也没有差异（>0.05）。令人惊讶的是，在尾静脉注射后约10分钟内，从这些大鼠收集的血浆中未检测到αCT11。为了研究可能调节αCT11在血液中降解的因素，将αCT11直接添加到从无I/R的正常大鼠分离的血浆中，并在不同实验条件下测量肽水平。与观察结果一致，在22℃和37℃下，血浆中αCT11在10分钟内发生显著降解，到30分钟时几乎检测不到。向分离的血浆中添加蛋白酶/磷酸酶（PTase/PPTase）抑制剂可减少这些反应。有趣的是，雄性和雌性大鼠血浆中αCT11降解没有显著差异。我们得出结论，αCT11的快速降解可能是在I/R模型中未观察到有益效果的原因，抑制或屏蔽PTase/PPTase活性可能是一种有助于肽疗法可行性的策略。
