Use of Synthetic Biology in the Development of Bacterial Adhesins for Skin Grafting applications

尽管最近医学在皮肤移植领域取得了进展，但仍有大量的皮肤移植治疗是不成功的。移植物的失败很大程度上是由于对待治疗的受损区域（通常称为伤床）的“粘附”不良。这些“坏”的伤口床难以粘附的原因之一是由于缺乏自然产生的粘性分子。因此，一种方法可能是使用一种胶水，将这些蛋白质中的一些引入伤口，或者可以与存在的少数蛋白质紧密结合，并在传入的移植细胞和待治疗的伤口床之间形成一种纽带。其中一种存在于糟糕的伤口床上的蛋白质是一种叫做1型胶原蛋白的分子。在这个项目中，我们计划使用一种新方法来生产一种“生物胶”，这种“生物胶”将通过1型胶原蛋白促进皮肤移植物粘附在坏的伤口床上。该项目将利用这样一个事实，即几种人类感染细菌会产生与胶原蛋白紧密结合的小分子，它们利用胶原蛋白粘在人体细胞表面，如呼吸道或皮肤。我们的想法是将这些小的蛋白质分子选择成一种蛋白质纤维——也由细菌产生，叫做鞭毛。设计这些蛋白质纤维的方法将遵循被称为合成生物学的新兴生物学领域的哲学。合成生物学的核心目标是以模块化的方式设计或重新设计生物部件，使其能够轻松地重复使用和重新设计，以用于替代应用。我们可以将其与乐高（Lego）进行类比，其中相同的部件可以用来制造汽车、房屋或起重机。为此目的，细菌的鞭毛可以接受这种操纵。这种蛋白质中直接形成纤维形式的部分可以被认为是蛋白质两端的两个模块，它们单独形成一个纤维形成的蛋白质装置，其中心部分可以被另一个模块取代。我们已经设计了这样一种装置，可以接受粘性蛋白质模块来代替这一部分，从而沿着纤维的长度显示数千种粘性蛋白质。在我们最初的研究中，我们放置了一种1型胶原蛋白分子，并在实验室环境中证明它可以结合1型胶原蛋白并改善皮肤样细胞的粘附。这个项目的目的是生产一系列这种1型胶原蛋白结合的粘性鞭毛，并测试它们将天然皮肤细胞粘附到表面的能力，并在我们开发的基于实验室的皮肤移植试验中提高这些细胞的粘附性。除了应用于皮肤移植之外，这些生物胶还可以在需要改善人体组织粘附性的情况下具有其他医疗应用。此外，这些易于操作的鞭毛显示装置将在这个新兴的合成生物学社区中具有广泛的应用前景。

Despite recent medical advances in the field of skin grafting there are still a large number of skin graft treatments that are unsuccessful. This failure of grafts is largely due to poor 'sticking' to the damaged area to be treated, commonly termed the wound bed. One of the reasons these 'bad' wound beds are difficult to adhere to is due to the lack of naturally occurring sticky molecules. Therefore one approach might be to use a glue that introduces some of these proteins into the wound or that can bind strongly to the few that are present and form a bond between incoming grafted cells and the wound bed to be treated. One of the proteins that is present in the bad wound beds is a molecule called Type 1 collagen. In this project we plan to use a novel approach to produce a 'bioglue' that will promote sticking of skin grafts to bad wound beds via type 1 collagen. This project will take advantage of the fact that several human infecting bacteria produce small molecules that bind strongly to collagen 1 which they use to stick down to human cell surfaces such as the airways or skin. Our idea is to engineer a selection of these small protein molecules into a protein fibre- also produced by bacteria, called the flagellum. The approach to engineering these protein fibres will follow the philosophy of an emerging biological field known as synthetic biology. At its core synthetic biology aims to design or re-engineer biological parts into often novel combinations in a modular manner that allows easy re-use and re-engineering of these parts for use in alternative applications. One can consider an analogy with Lego in which the same component parts can be used to produce a car, a house or a crane. To this end the bacteria flagellum is amenable to this kind of manipulation. The sections of this protein that direct formation of a fibre form can be thought of as two modules at each end of the protein which in isolation would form a fibre forming protein device with a central section that can be replaced with another module. We have engineered such a device to accept sticky protein modules in place of this section and so display thousands of these sticky proteins along the length of the fibre. In our initial studies we have placed one of these type 1 collagen molecules and shown that it can bind type 1 collagen and improve sticking of skin-like cells in a laboratory setting. The aim of this project is to produce a range of these type 1 collagen binding sticky flagella and test their ability to stick natural skin cells to surfaces and also improve adherence of these cells in a laboratory based skin grafting assay that we have developed.As well as applications to skin grafting these bioglues may also have other medical applications in situations where improving adherence of human tissue is required. In addition these easy to manipulate flagella display devices will be of great use to this emerging synthetic biology community for a range of future applications.