Department of Biomedical Engineering, The Cleveland Clinic, 9500 Euclid Avenue, ND 20, Cleveland, OH, 44195, USA.
Department of Chemical and Biomedical Engineering, Cleveland State University, 2121 Euclid Avenue, Cleveland, OH, 44115, USA.
Drug Deliv Transl Res. 2018 Aug;8(4):964-984. doi: 10.1007/s13346-017-0419-y.
Growth of abdominal aortic aneurysms (AAA), localized aortal wall expansions, is driven by the disruption and subsequent loss of aortal wall elastic fibers by matrix metalloproteases (MMPs). Since elastic fibers do not naturally regenerate or repair, arresting/reversing AAA growth has not been possible. Previously, we showed utility of doxycycline (DOX), an MMP inhibitor drug, to stimulate elastic matrix neoassembly and crosslinking at low microgram per milliliter doses in addition to inhibiting MMPs. We currently show in aneurysmal smooth muscle cell (SMC) cultures that effects of exogenous DOX in this dose range are linked to its upregulation of transforming growth factor beta (TGF-β1) via its inhibition of the regulatory protein c-Jun-N-terminal kinase 2 (JNK 2). We have identified a DOX dose range that stimulates elastogenesis and crosslinking without adversely impacting cell viability. Using JNK 2 inhibition as a metric for pro-regenerative matrix effects of DOX, we further demonstrate that sustained, steady-state release of DOX at the useful dose, from poly(ethylene glycol)-poly(lactic glycolic acid) nanoparticles (NPs), provides pro-elastogenic and anti-proteolytic effects that could potentially be more pronounced than that of exogenous DOX. We attribute these outcomes to previously determined synergistic effects provided by cationic amphiphile groups functionalizing the polymer NP surface. Released DOX inhibited expression and phosphorylation of JNK to likely increase expression of TGF-β1, which is known to increase elastogenesis and lysyl oxidase-mediated crosslinking of elastic matrix. Our results suggest that JNK inhibition is a useful metric to assess pro-elastic matrix regenerative effects and point to the combinatorial regenerative benefits provided by DOX and cationic-functionalized NPs.
腹主动脉瘤（AAA）的生长是由于基质金属蛋白酶（MMPs）破坏和随后丧失主动脉壁弹性纤维所驱动的。由于弹性纤维不能自然再生或修复，因此阻止/逆转 AAA 的生长是不可能的。先前，我们发现多西环素（DOX），一种 MMP 抑制剂药物，在低微克/毫升剂量下除了抑制 MMPs 之外，还具有刺激弹性基质新组装和交联的作用。我们目前在动脉瘤平滑肌细胞（SMC）培养物中表明，这种剂量范围内外源性 DOX 的作用与其通过抑制调节蛋白 c-Jun-N-末端激酶 2（JNK 2）而上调转化生长因子β（TGF-β1）有关。我们已经确定了一个 DOX 剂量范围，该范围刺激了弹性蛋白形成和交联，而不会对细胞活力产生不利影响。我们进一步使用 JNK 2 抑制作为 DOX 促再生基质作用的指标，证明了在有用剂量下从聚乙二醇-聚（乳酸-乙醇酸）纳米颗粒（NPs）中持续、稳定的 DOX 释放具有促弹性蛋白形成和抗蛋白水解的作用，其效果可能比外源性 DOX 更为明显。我们将这些结果归因于通过阳离子两亲性基团官能化聚合物 NP 表面提供的先前确定的协同作用。释放的 DOX 抑制 JNK 的表达和磷酸化，可能增加 TGF-β1 的表达，已知 TGF-β1 可增加弹性蛋白形成和赖氨酰氧化酶介导的弹性基质交联。我们的结果表明，JNK 抑制是评估促弹性基质再生作用的有用指标，并指出 DOX 和阳离子官能化 NPs 提供的组合再生益处。
