Defining the role of mSMGP/mPIP as an immunoregulatory molecule in host defense

定义 mSMGP/mPIP 作为免疫调节分子在宿主防御中的作用

• 批准号: RGPIN-2014-05539
• 负责人: Myal, Yvonne
• 金额: $ 1.89万
• 依托单位: University of Manitoba
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2014
• 资助国家: 加拿大
• 起止时间: 2014-01-01 至 2015-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=567229
• 关键词: Defining; role; mSMGP; mPIP; immunoregulatory

Defining a role for mSMGP as an immunoregulatory molecule in host defense HYPOTHESIS: The mouse submaxillary (submandibular) gland protein, mSMGP, is an important immunoregulatory molecule that plays a role in both innate and adaptive immune host defense. PROPOSAL: To examine mSMGP’s influence on the adaptive immune system and to delineate the mechanisms of its innate antimicrobial activities. My laboratory is interested in the biology and physiology of the submandibular gland. The submandibular gland in the mouse, as in most other mammals, exhibits both endocrine and exocrine functions, and is the site of synthesis of several biologically active polypeptides, including hormones, growth factors, and digestive enzymes. Many of these proteins are well studied and characterized, however, the function of several others remain elusive. I have identified a gene that is highly expressed in this gland and whose protein we termed the mouse submaxillary gland protein (mSMGP). The function of mSMGP has not been delineated. Following this initial discovery, we subsequently found that not only was mSMGP expressed in salivary glands, but was also expressed at immunologically important ports of entry for pathogens, such as skin, eyes and ears and the secreted protein found in the bodily fluids produced by these tissues such as saliva, tears and sweat. We further demonstrated that mSMGP binds to and aggregates bacteria including several human and mouse oral strains, prohibiting their multiplication and spread. These observations led us to hypothesize that mSMGP plays a role in innate host defense. However, clues that mSMGP may have a broader role in immunity have come from other studies carried out on a human homologue which was shown, like mSMGP, not only to possess the ability to bind to bacterial strains but was capable of binding to the CD4 molecule and inhibit T lymphocyte apoptosis. Furthermore, using a mSMGP knockout model which we generated as a tool to address protein function, we demonstrated that knockout mice had abnormal lymphocytes that exhibited abnormal proliferation rates, had impaired Th1 and possibly, Th2 immune responses and had increased susceptibility to Leishmania major infection. We demonstrated for the first time that mSMGP was involved in cell mediated immunity. We also showed that KO mice saliva was less effective in aggregating oral bacteria and that the composition of the oral flora was different from its wild type counterpart, with a preponderance of representation from the genus Streptococcus. Additionally we showed that loss of mSMGP function resulted in the up regulation of a class of salivary proteins recently identified as putative markers of disease. Our current objectives are to investigate the role of the mSMGP in cell mediated immunity and to delineate the mechanism of mSMGP antimicrobial activities. Protection against invading organisms or infection, particularly via oral contamination is to date, poorly understood. The proposed studies are among the very few that approach the infection phenomenon from an oral perspective. I anticipate this study will yield critical insights into the function and biology of the mSMGP, and will further contribute to increasing our understanding of submandibular gland biology and immunity.

确定mSMGP作为免疫调节分子在宿主防御中的作用假说：小鼠颌下腺蛋白mSMGP是一种重要的免疫调节分子，在天然免疫和获得性免疫宿主防御中发挥作用。建议：检测mSMGP对获得性免疫系统的影响，并阐明其天然抗菌活性的机制。我的实验室对颌下腺的生物学和生理学很感兴趣。与大多数其他哺乳动物一样，小鼠的颌下腺具有内分泌和外分泌功能，是几种生物活性多肽的合成场所，包括激素、生长因子和消化酶。这些蛋白质中的许多都得到了很好的研究和表征，然而，其他几个蛋白质的功能仍然难以捉摸。我已经确定了一种在这个腺体中高度表达的基因，其蛋白被我们称为小鼠颌下腺蛋白(MSMGP)。MSMGP的功能尚未阐明。根据这一初步发现，我们随后发现，mSMGP不仅在唾液腺中表达，而且在病原体的免疫重要入境点也有表达，如皮肤、眼睛和耳朵，以及这些组织产生的体液中的分泌蛋白，如唾液、泪水和汗液。我们进一步证明了mSMGP结合并聚集了包括几种人和小鼠口腔菌株在内的细菌，阻止了它们的繁殖和传播。这些观察结果使我们假设mSMGP在先天性宿主防御中发挥作用。然而，mSMGP在免疫中可能具有更广泛作用的线索来自于对人类同源物进行的其他研究，如mSMGP，它不仅具有与细菌菌株结合的能力，而且能够与CD4分子结合并抑制T淋巴细胞凋亡。此外，使用我们建立的mSMGP基因敲除模型作为研究蛋白质功能的工具，我们证明了基因敲除小鼠具有异常的淋巴细胞，表现出异常的增殖率，损害了Th1和可能的Th2免疫反应，并增加了对利什曼原虫重大感染的易感性。我们首次证明了mSMGP参与了细胞免疫。我们还表明，KO小鼠的唾液在聚集口腔细菌方面效率较低，口腔菌群的组成与野生型不同，主要来自链球菌属。此外，我们还发现，mSMGP功能的丧失导致了一类唾液蛋白的上调，这些唾液蛋白最近被认为是疾病的假定标志。我们目前的目标是研究mSMGP在细胞免疫中的作用，并阐明mSMGP的抗菌活性机制。到目前为止，对入侵生物或感染的保护措施，特别是通过口腔污染的保护措施，知之甚少。拟议的研究是为数不多的从口腔角度探讨感染现象的研究之一。我预计这项研究将对mSMGP的功能和生物学产生重要的见解，并将进一步有助于增加我们对颌下腺生物学和免疫的了解。