Molecular characterisation of Toll-like receptor 4 biased signalling through the TIR-domain-containing adapter-inducing interferon-beta

在所有年龄段的人群中制定成功的疫苗接种战略不仅对整个生命过程中的健康老龄化很重要，而且对减少抗菌素耐药性也很重要。为预防动物疾病和减轻人畜共患病原体负担而接种动物疫苗，对于改善动物健康和福利以及加强粮食安全至关重要。佐剂是用于提高人和动物疫苗效率的分子。许多佐剂靶向一类识别病原微生物的受体，称为模式识别受体（PRRs）。其中一种PRR， toll样受体4 (TLR4)，对于识别革兰氏阴性细菌和保护宿主免受这些细菌的感染很重要。然而，这种受体的过度活跃会导致严重的炎症，人们认为，随着年龄的增长，TLR4的激活增加是许多老年人常见疾病的基础。TLR4激活了独立的、但相互关联的免疫反应。一只手臂，通过一种叫做toll -白细胞介素1受体（TIR）的蛋白质-含结构域的适配器诱导干扰素- β (Trif)，在促进保护性疫苗反应的发展方面非常有效。另一种是通过一种名为髓样分化初级反应88 （MyD88）的蛋白质，保护动物免受革兰氏阴性细菌感染。一种佐剂分子单磷酰脂质A （MPLA）选择性地激活人体内的Trif，但其发生的机制尚不清楚。在本研究中，我们将通过改变TLR4的结构来确定MPLA如何激活TLR4-Trif，并确定这是否会改变Trif和/或MyD88的激活。我们还将确定MPLA激活免疫细胞后Trif形成的蛋白复合物。最后，我们将尝试识别分子，选择性地靶向TLR4和Trif驱动的免疫反应，以产生用于疫苗佐剂和其他治疗应用的新化合物。

Development of successful vaccination strategies in humans of all ages is important not only for healthy ageing across the lifecourse, but also to reduce antimicrobial resistance. Vaccination of animals both to prevent animal diseases and to reduce the burden of zoonotic pathogens is critical to improve animal health and welfare as well as increasing food security. Adjuvants are molecules used to to improve the efficiency of vaccines in man and animals. Many adjuvants target a class of receptors that recognise pathogenic micro-organisms called Pattern Recognition Receptors (PRRs). One PRR, Toll-like Receptor 4 (TLR4), is important for recognising Gram negative bacteria and protecting the host against infections with these bacterial species. Over activity of this receptor, however, leads to severe inflammation and it is thought that increased activation of TLR4 as we age underpins many of the conditions commonly seen in an ageing population. TLR4 activates separate, but linked arms of the immune response. One arm, through a protein called Toll-Interleukin 1 Receptor (TIR)-domain-containing adapter-inducing interferon-beta (Trif), is very efficient at facilitating the development of protective vaccine responses. The other, through a protein called Myeloid Differentiation Primary Response 88 (MyD88), protects animals against Gram negative bacterial infections. An adjuvant molecule monophosphoryl lipid A (MPLA) selectively activates Trif in humans, but the mechanisms by which this occurs are not understood. In this grant we will determine how MPLA activates TLR4-Trif by changing the structure of TLR4 and determining whether this alters activation of Trif and/or MyD88. We will also determine the protein complexes formed by Trif after MPLA activation of immune cells. Finally we will try and identify molecules that will selectively target TLR4 and Trif driven immune responses to generate new compounds for vaccine adjuvants and other therapeutic applications.