Department of Surgery, Indiana University School of Medicine, Indianapolis, IN 46202, USA.
Am J Physiol Heart Circ Physiol. 2010 May;298(5):H1529-36. doi: 10.1152/ajpheart.01087.2009. Epub 2010 Feb 19.
Toll-like receptor 2 (TLR2), a key component of the innate immune system, is linked to inflammation and myocardial dysfunction after ischemia-reperfusion injury (I/R). Treatment of the heart with mesenchymal stem cells (MSCs) is known to improve myocardial recovery after I/R in part by paracrine factors such as VEGF. However, it is unknown whether TLR2 activation on the MSCs affects MSC-mediated myocardial recovery and VEGF production. We hypothesized that the knockout of TLR2 on the MSCs (TLR2KO MSCs) would 1) improve MSC-mediated myocardial recovery and 2) increase myocardial and MSC VEGF release. With the isolated heart perfusion system, Sprague-Dawley rat hearts were subjected to I/R and received one of three intracoronary treatments: vehicle, male wild-type MSCs (MWT MSCs), or TL2KO MSCs. All treatments were performed immediately before ischemia, and heart function was measured continuously. Postreperfusion, heart homogenates were analyzed for myocardial VEGF production. Contrary to our hypothesis, only MWT MSC treatment significantly improved the recovery of left ventricular developed pressure and the maximal positive and negative values of the first derivative of pressure. In addition, VEGF production was greatest in hearts treated with MWT MSCs. To investigate MSC production of VEGF, MSCs were activated with TNF in vitro and the supernatants collected for ELISA. In vitro basal levels of MSC VEGF production were similar. However, with TNF activation, MWT MSCs produced significantly more VEGF, whereas activated TLR2KO MSC production of VEGF was unchanged. Finally, we observed that MWT MSCs proliferated more rapidly than TLR2KO MSCs. These data indicate that TLR2 may be essential to MSC-mediated myocardial recovery and VEGF production.
Toll 样受体 2（TLR2）是先天免疫系统的关键组成部分，与缺血再灌注损伤（I/R）后的炎症和心肌功能障碍有关。用间充质干细胞（MSCs）治疗心脏已知可以通过旁分泌因子如 VEGF 改善 I/R 后的心肌恢复。然而，TLR2 在 MSCs 上的激活是否影响 MSC 介导的心肌恢复和 VEGF 产生尚不清楚。我们假设 MSCs 上 TLR2 的敲除（TLR2KO MSCs）将 1）改善 MSC 介导的心肌恢复，2）增加心肌和 MSC VEGF 释放。在离体心脏灌注系统中，用 Sprague-Dawley 大鼠心脏进行 I/R，并接受三种冠状动脉内治疗之一：载体、雄性野生型 MSCs（MWT MSCs）或 TLR2KO MSCs。所有治疗均在缺血前进行，并连续测量心功能。再灌注后，分析心脏匀浆中心肌 VEGF 的产生。与我们的假设相反，只有 MWT MSC 治疗才能显著改善左心室发展压的恢复和压力一阶导数的最大正、负数值。此外，用 MWT MSCs 治疗的心脏中 VEGF 的产生最大。为了研究 MSC 产生的 VEGF，用 TNF 在体外激活 MSCs，并收集上清液进行 ELISA 分析。MSC 基础水平的 VEGF 产生相似。然而，在 TNF 激活后，MWT MSCs 产生的 VEGF 明显更多，而激活的 TLR2KO MSC 产生的 VEGF 不变。最后，我们观察到 MWT MSCs 的增殖速度快于 TLR2KO MSCs。这些数据表明 TLR2 可能对 MSC 介导的心肌恢复和 VEGF 产生至关重要。
