PYK2 is a Ca(2+)-dependent, nonreceptor protein tyrosine kinase that is involved in the induction of left ventricular hypertrophy (LVH) and its transition to heart failure. We and others have previously investigated PYK2's function in vitro using cultured neonatal and adult rat ventricular myocytes as model systems. However, the function of PYK2 in the in vivo adult heart remains unclear. Here we evaluate the effect of PYK2 inhibition following myocardial infarction (MI) using adenoviral (Adv) overexpression of the C-terminal domain of PYK2, known as CRNK. First we demonstrate that CRNK functions as a dominant-negative inhibitor of PYK2-dependent signaling, presumably by displacing PYK2 from focal adhesions and costameres. Then, male Sprague-Dawley rats (~300 g) underwent permanent left anterior descending coronary artery ligation. One wk post-MI, either Adv-GFP (n=34) or Adv-CRNK (n=28) was administered (10(10) pfu, 0.1 ml) via catheter-based, Optison-mediated gene transfer. LV structure and function were evaluated by echocardiography 1 and 3 wk after gene transfer, and LV tissue was analyzed by real-time RT-PCR and Western blotting. CRNK overexpression was readily detected by Western blotting 1 wk following gene transfer. Adv-CRNK improved overall survival (P=0.03; Logrank Test) and LV fractional shortening (23+/-2% vs. 31+/-2% for Adv-GFP vs. Adv-CRNK infected animals, respectively; P<0.05). Whereas MI hearts exhibited increased beta-, and decreased alpha-myosin heavy chain (MHC) mRNA expression characteristic of LVH, Adv-CRNK reversed the MHC isoenzyme switch (3.3+/-1.4 fold increase in alpha MHC; 0.4+/-0.1 fold decrease in beta MHC; P<0.05 for both). In summary, CRNK gene transfer improves survival, increases LV function, and alters MHC gene expression suggesting an attenuation of LV remodeling post-MI.

中文翻译：

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CRNK 基因转移在心肌梗塞后左心室重构期间改善功能并逆转肌球蛋白重链同工酶转换。

PYK2 是一种 Ca(2+) 依赖的非受体蛋白酪氨酸激酶，参与诱导左心室肥大 (LVH) 及其向心力衰竭的转变。我们和其他人以前使用培养的新生和成年大鼠心室肌细胞作为模型系统在体外研究了 PYK2 的功能。然而，PYK2 在体内成人心脏中的功能仍不清楚。在这里，我们使用 PYK2 的 C 末端结构域（称为 CRNK）的腺病毒 (Adv) 过表达来评估心肌梗塞 (MI) 后 PYK2 抑制的影响。首先，我们证明 CRNK 作为 PYK2 依赖性信号传导的显性负抑制剂起作用，大概是通过从粘着斑和肋骨上置换 PYK2。然后，雄性 Sprague-Dawley 大鼠 (~300 g) 接受了永久性左冠状动脉前降支结扎术。MI 后一周，通过基于导管的 Optison 介导的基因转移，给予 Adv-GFP（n=34）或 Adv-CRNK（n=28）（10（10）pfu，0.1 毫升）。在基因转移后第 1 周和第 3 周通过超声心动图评估 LV 结构和功能，并通过实时 RT-PCR 和蛋白质印迹分析 LV 组织。在基因转移后 1 周，通过蛋白质印迹很容易检测到 CRNK 过表达。Adv-CRNK 改善了总体存活率（P=0.03；Logrank 检验）和 LV 缩短分数（Adv-GFP 与 Adv-CRNK 感染的动物分别为 23+/-2% 与 31+/-2%；P<0.05 ）。MI 心脏表现出 LVH 特征性的 β-肌球蛋白重链 (MHC) mRNA 表达增加和降低，而 Adv-CRNK 逆转了 MHC 同工酶开关（α MHC 增加了 3.3+/-1.4 倍；0.4+/-0.1 倍） β MHC 降低；两者的 P < 0.05）。总之，