Developing a non-animal model system to investigate bitter tastants as new treatments for asthma

最近的观察表明，苦味化合物会导致肺部气道打开，这表明这些化合物在治疗哮喘方面有一定作用。这是出乎意料的，因为苦味检测被认为是保护动物（包括人类）免受摄入有害的，通常是苦味的化合物的行为。苦味化合物是由舌头上的TAS2Rs受体家族检测到的。然而，有趣的是，尚不清楚这些TAS2Rs是否参与哮喘治疗，或者这种作用是否通过未识别的蛋白质发生。越来越多的证据表明，这些化合物可能通过与TAS2R无关的靶点起作用，但这些靶点仍有待发现。对苦味化合物及其在哮喘中的作用方式的研究主要集中在使用从豚鼠和小鼠身上获得的肺组织，但也有来自人类的肺组织。这项研究包括使用这种动物组织来确定苦味化合物引发肌肉松弛的过程（与缓解哮喘诱导有关）。利用这种方法，人们期望每种苦味化合物的作用可以被绘制出来，并由此获得的信息用于开发改善慢性哮喘的治疗方法。不幸的是，迄今为止，苦味化合物已被证明以多种方式介导其扩张作用，其中一些独立于这些动物组织中已知的tas2rs依赖过程。因此，确定这些机制非常重要。开发替代的非动物系统来研究苦味化合物的机制将大大减少动物在这一研究领域的使用。这项研究还将提供动物模型中无法获得的实验方法，从而在哮喘治疗方面取得突破。我们建议开展一个两阶段系统的苦味剂研究，首先使用社会变形虫盘基骨柱来确定这些苦味剂是如何起作用的，然后使用人类细胞来证实我们的发现与哮喘治疗有关。我们已经证明盘基ostelium可以成功地用于鉴定与人类健康有关的化合物的新的作用机制。该模型的有效使用是毋庸置疑的，因为它已被用于发现双相情感障碍药物的机制(Williams et al . (2002) Nature, 417, 292-5；威廉姆斯（2005）在Neuro-Psychopharmacol。和杂志。精神病学29,1029-37)，最广泛使用的癫痫治疗机制，丙戊酸(Xu et al . (2007) Euk Cell, 6, 899-90；Chang et al .（2012）疾病模型与机制，5,115 -124；Chang et al（2013）疾病的神经生物学，62C, 296-306)和MCT生酮饮食的潜在治疗机制(Chang et al（2013）神经药理学，69,105-14；Williams and Walker（2013）生物化学。Soc。反式,41岁,1625 - 8)。它还被用于鉴定两种结构独立的苦味剂的新分子靶点(Robery et al . (2013) Journal of Cell Science, 126, 5465-76；Waheed et al (2014) British Journal of Pharmacology, 171, 2659-70)。因此，该项目将使用盘基骨菌作为动物替代模型，确定治疗哮喘的苦味化合物的治疗相关靶点。最终，我们的目标是将盘基骨柱作为一种非动物系统来开发，以揭示苦味化合物介导其作用的机制，并确定治疗哮喘的新分子靶点。

The recent observation that bitter tasting compounds cause the opening of airways in the lung suggest a role for these compounds in the treatment of asthma. This is unexpected, since bitter taste detection was thought act to protect animals (including humans) from ingesting harmful, often bitter, compounds. Bitter tasting compounds are detected by a family of receptors called TAS2Rs that are found on the tongue. Intriguingly, however, it remains unclear if these TAS2Rs are involved in asthma treatment, or if this effect occurs through unidentified proteins. Increasing evidence suggests that these compounds may act through TAS2R independent targets, but these targets are still to be discovered. Research into bitter compounds and the way they work in asthma has focused on using lung tissue obtained from guinea pigs and mice, but also from humans. This research involves using this animal tissue to identify the process that bitter compounds trigger to cause muscle relaxation (related to relieving asthma induction). Using this approach, it was expected that the effect of each bitter compound could be mapped, and resulting information used to develop improved treatments for chronic asthma. Unfortunately, to date, bitter tasting compounds have been shown to mediate their dilatory effects in multiple ways, some acting independently of known TAS2Rs-dependent processes within these animal tissues. Identifying these mechanisms is thus highly important.Developing alternate non-animal systems to investigate the mechanisms of bitter tasting compounds will significantly reduce the use of animals in this research area. This research will also provide experimental approaches unavailable in animal models leading to breakthroughs in the treatment of asthma. We propose to develop a two stage system bitter tastant research, initially using the social amoeba Dictyostelium to identify how these tastants work, and then using human cells to confirm our discoveries are relevant to asthma treatment. We have shown that Dictyostelium can be successfully used to identify new mechanisms of action for compound relevant to human health. The effective use of this model is beyond doubt, as it has been used to find the mechanism of bipolar disorder drugs (Williams et al (2002) Nature, 417, 292-5; Williams (2005) Prog. in Neuro-Psychopharmacol. and Biol. Psychiatry 29, 1029-37), the mechanism of the most wildly used epilepsy treatment, valproic acid (Xu et al (2007) Euk Cell, 6, 899-90; Chang et al (2012) Disease Models and Mechanism, 5, 115-124; Chang et al (2013) Neurobiology of Disease, 62C, 296-306) and the underlying therapeutic mechanism of the MCT ketogenic diet (Chang et al (2013) Neuropharmacology, 69,105-14; Williams and Walker (2013) Biochem. Soc. Trans, 41,1625-8). It has also been used to identify novel molecular targets for two structurally independent bitter tastants been (Robery et al (2013) Journal of Cell Science, 126, 5465-76; Waheed et al (2014) British Journal of Pharmacology, 171, 2659-70). Hence therapeutically relevant targets for bitter compounds in the treatment of asthma will be identified in the project using Dictyostelium as an animal replacement model.Ultimately, our goal is to develop Dictyostelium as a non-animal system to uncover the mechanisms whereby bitter tasting compounds mediate their effects, to identify novel molecular targets for the treatment of asthma.