Targeting Succinate Signaling Impedes Periodontitis Progression

摘要 2 型糖尿病被认为是导致更严重和进展性糖尿病的重要危险因素 牙周炎。糖尿病可能会通过代谢失调加速牙周炎， 细菌定植、炎症和骨质流失的变化。我们最近发现琥珀酸 激活琥珀酸受体 (SucnR1) 以刺激破骨细胞生成和骨吸收。我们的 初步数据进一步显示（1）龈沟液（GCF）中琥珀酸盐含量升高 牙周炎患者的升高程度明显更高 牙周炎和 T2D； (2) T2D小鼠自发性牙周炎伴有牙周炎升高 牙周组织中的琥珀酸水平和胃肠道微生物群的改变与正常情况相比 老鼠； (3)琥珀酸在体外有利于牙周病原菌的生长； (4)外源性琥珀酸 增强野生型（WT）牙周骨质流失； (5) 牙周骨丢失量为 在 SucnR1 敲除小鼠 (KO) 小鼠中减轻。当前的提案建立在强有力的基础上 确定琥珀酸升高是否会加速牙周病的初步数据 进展。我们将使用小鼠模型来测试我们的假设，即针对琥珀酸 信号传导可防止牙周病加速发病。在目标 1 中，我们将使用喂食的小鼠 正常饮食下，喂食高脂肪饮食（HFD）的小鼠会出现高血糖，而琥珀酸盐 受体敲除小鼠 (SucnR1_KO) 以确定琥珀酸/SucnR1 信号传导是否有效 在正常和高血糖情况下影响全身反应并改变口腔微生物群 条件。我们将使用细菌从牙周部位转移到无菌小鼠来测试 通过细菌引起的骨质流失来测量致病性。我们的工作假设是细菌 来自 HFD 糖尿病小鼠的细菌比来自匹配血糖正常小鼠的细菌会导致更多的骨质流失 控制。在目标 2 中，我们将确定琥珀酸是否激活 SucnR1 以增强牙周功能 炎症刺激引起的骨质流失。在目标 3 中，我们将确定是否阻塞 前破骨细胞中的琥珀酸信号传导可减轻牙周骨质流失。我们将使用 lysMCre， SucnR1L/L小鼠模型评估琥珀酸信号传导是否通过其受体增强 非炎症刺激引起的骨质流失。我们还将测试特定 SucnR1 的功效 拮抗剂预防自发发展的 T2D 小鼠模型中的牙周炎 牙周炎。我们认为，通过激活 SucnR1，琥珀酸在以下方面具有重要意义： 牙周病，通过描述这种新机制，我们将有助于预防 糖尿病患者牙周骨质流失。

Abstract Type 2 Diabetes is recognized as an important risk factor for more severe and progressive periodontitis. Diabetic condition may accelerate periodontitis through metabolic dysregulation, shift in bacterial colonization, inflammation, and bone loss. We recently found that succinate activates succinate receptor (SucnR1) to stimulate osteoclastogenesis and bone resorption. Our preliminary data further show (1) succinate was elevated in the gingival crevicular fluid (GCF) from periodontitis patients and the elevation was significantly greater in patients with both periodontitis and T2D; (2) spontaneous periodontitis in T2D mice was accompanied by elevated succinate levels in the periodontium and altered gastrointestinal microbiome compare to normal mice; (3) succinate favors the growth of periodontal pathogens in vitro; (4) exogenous succinate enhances periodontal bone loss in wild type (WT); and (5) the periodontal bone loss is mitigated in SucnR1 knock out mice (KO) mice. The current proposal is built on strong preliminary data to determine whether succinate elevation accelerates periodontal disease progression. We will employ mouse models to test our hypotheses that targeting succinate signaling prevents accelerated periodontal disease pathogenesis. In Aim 1 we will use mice fed on normal diet, mice fed on High Fat Diet (HFD) which become hyperglycemic, and succinate receptor knock out mice (SucnR1_KO) to determine whether succinate/SucnR1 signaling influences systemic response and alters oral microbiota in normal and hyperglycemia conditions. We will use bacterial transfer from the periodontal site to germ free mice to test the pathogenicity as measured by bacteria-induced bone loss. Our working hypothesis is bacteria from HFD diabetic mice will induce more bone loss than bacteria from matched normoglycemic controls. In Aim 2 we will determine whether succinate activates SucnR1 to enhance periodontal bone loss stimulated by inflammation stimulus. In Aim 3 we will determine whether blocking succinate signaling in pre-osteoclasts alleviates periodontium bone loss. We will use lysMCre, SucnR1L/L mouse model to assess whether succinate signaling through its receptor to enhance non-inflammatory stimuli induced bone loss. We will also test the efficacy of a specific SucnR1 antagonist in preventing periodontitis in a T2D mouse model that spontaneously develop periodontitis. We propose that via activation of SucnR1, succinate has significant implications in periodontal disease and by delineating this novel mechanism, we will help to prevent periodontal bone loss in diabetic patients.