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

尽管最近在皮肤移植领域的医学进步，仍然有大量的皮肤移植治疗是不成功的。移植物的这种失败主要是由于对待治疗的受损区域（通常称为伤口床）的不良“粘附”。这些“坏”伤口床难以粘附的原因之一是由于缺乏天然存在的粘性分子。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强烈结合，并在即将到来的移植细胞和待治疗的伤口床之间形成结合。其中一种存在于伤口床中的蛋白质是一种称为1型胶原蛋白的分子。在这个项目中，我们计划使用一种新的方法来生产一种“粘合剂”，它将通过1型胶原促进皮肤移植物粘附到严重的伤口床上。该项目将利用几种人类感染细菌产生与胶原蛋白1强烈结合的小分子的事实，这些小分子用于粘附在人体细胞表面，如气道或皮肤。我们的想法是将这些小蛋白质分子的选择工程化为蛋白质纤维-也由细菌产生，称为鞭毛。设计这些蛋白质纤维的方法将遵循一个新兴的生物学领域的哲学，即合成生物学。合成生物学的核心目标是以模块化的方式将生物部件设计或重新设计成通常新颖的组合，从而可以轻松地重新使用和重新设计这些部件以用于替代应用。人们可以考虑用乐高积木做类比，其中相同的组成部分可以用来生产汽车，房屋或起重机。为了达到这个目的，细菌的鞭毛可以接受这种操纵。这种蛋白质的指导纤维形式形成的部分可以被认为是在蛋白质的每一端的两个模块，其在分离时将形成具有可以被另一个模块替换的中心部分的纤维形成蛋白质装置。我们已经设计了这样一种装置来接受粘性蛋白质模块来代替这一部分，因此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，我们已经放置了这些1型胶原蛋白分子之一，并表明它可以结合1型胶原蛋白，并在实验室环境中改善皮肤样细胞的粘附。本项目的目的是生产一系列1型胶原蛋白结合粘性鞭毛，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改善这些细胞的粘附性。除了皮肤移植应用外，这些鞭毛还可能在需要改善人体组织粘附性的情况下具有其他医学应用。此外，这些易于操作的鞭毛显示设备将对这个新兴的合成生物学社区在未来的一系列应用中有很大的用处。

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.