DWI-Leibniz-Institute for Interactive Materials e.V., Forckenbeckstr. 50, 52056 Aachen, Germany.
Department of Anesthesiology, Intensive Care and Pain Medicine, University Hospital Münster, Albert-Schweitzer-Campus 1, Bldg. A1, 48149 Münster, Germany.
Biomater Sci. 2021 Dec 21;10(1):85-99. doi: 10.1039/d1bm01591e.
Neutrophil extracellular traps (NETs) are web-like chromatin structures produced and liberated by neutrophils under inflammatory conditions which also promote the activation of the coagulation cascade and thrombus formation. The formation of NETs is quite prominent when blood comes in contact with artificial surfaces like extracorporeal circuits, oxygenator membranes, or intravascular grafts. DNase I as a factor of the host defense system, digests the DNA backbone of NETs, which points out its treatment potential for NET-mediated thrombosis. However, the low serum stability of DNase I restricts its clinical/therapeutic applications. To improve the bioavailability of the enzyme, DNase I was conjugated to the microgels (DNase I MG) synthesized from highly hydrophilic -(2-hydroxypropyl) methacrylamide (HPMA) and zwitterionic carboxybetaine methacrylamide (CBMAA). The enzyme was successfully conjugated to the microgels without any alternation to its secondary structure. The value representing the enzymatic activity of the conjugated DNase I was calculated to be 0.063 μM demonstrating a high enzyme-substrate affinity. The DNase I MGs were protein repellant and were able to digest NETs more efficiently compared to free DNase in a biological media, remarkably even after long-term exposure to the stimulated neutrophils continuously releasing NETs. Overall, the conjugation of DNase I to a non-fouling microgel provides a novel biohybrid platform that can be exploited as non-thrombogenic active microgel-based coatings for blood-contacting surfaces to reduce the NET-mediated inflammation and microthrombi formation.
中性粒细胞胞外陷阱 (NETs) 是在炎症条件下由中性粒细胞产生并释放的网状染色质结构，同时也促进了凝血级联反应和血栓形成的激活。当血液接触到人工表面，如体外循环、氧合器膜或血管内移植物时，NETs 的形成非常明显。DNase I 作为宿主防御系统的一个因素，可消化 NETs 的 DNA 骨架，这表明其在 NET 介导的血栓形成中的治疗潜力。然而，DNase I 的血清稳定性低限制了其临床/治疗应用。为了提高酶的生物利用度，将 DNase I 与由高亲水性 -（2-羟丙基）甲基丙烯酰胺（HPMA）和两性离子羧基甜菜碱甲基丙烯酰胺（CBMAA）合成的微凝胶（DNase I MG）偶联。该酶成功地与微凝胶偶联，而其二级结构没有任何改变。代表偶联 DNase I 酶活性的 值计算为 0.063 μM，表明酶-底物亲和力很高。与游离的 DNase 相比，DNase I MGs 具有蛋白质排斥性，并且能够在生物介质中更有效地消化 NETs，即使在长期暴露于不断释放 NETs 的刺激中性粒细胞后也是如此。总的来说，将 DNase I 偶联到非污染的微凝胶上提供了一种新型的生物杂交平台，可以作为非血栓形成的主动基于微凝胶的涂层用于与血液接触的表面，以减少 NET 介导的炎症和微血栓形成。
