University of South Florida, Department of Cell Biology, Microbiology, and Molecular Biology, 4202 East Fowler Ave, ISA2015, Tampa, FL 33620, USA.
Integrated BioSciences, School of Clinical Dentistry, The University of Sheffield, 19 Claremont Crescent, Sheffield S10 2TA, UK.
Microbiology (Reading). 2019 Nov;165(11):1181-1197. doi: 10.1099/mic.0.000851.
Key to onset and progression of periodontitis is a complex relationship between oral bacteria and the host. The organisms most associated with severe periodontitis are the periodontal pathogens of the red complex: , and . These organisms express sialidases, which cleave sialic acid from host glycoproteins, and contribute to disease through various mechanisms. Here, we expressed and purified recombinant sialidase SiaPG (PG_0352) and characterized its activity on a number of substrates, including host sialoglycoproteins and highlighting the inability to cleave diacetylated sialic acids - a phenomenon overcome by the NanS sialate-esterase from . Indeed SiaPG required NanS to maximize sialic acid harvesting from heavily O-acetylated substrates such as bovine salivary mucin, hinting at the possibility of interspecies cooperation in sialic acid release from host sources by these members of the oral microbiota. Activity of SiaPG and was inhibited using the commercially available chemotherapeutic zanamivir, indicating its potential as a virulence inhibitor, which also inhibited sialic acid release from mucin, and was capable of inhibiting biofilm formation of on oral glycoprotein sources. Zanamivir also inhibited attachment and invasion of oral epithelial cells by and other periodontal pathogens, both in monospecies but also in multispecies infection experiments, indicating potential to suppress host-pathogen interactions of a mixed microbial community. This study broadens our understanding of the multifarious roles of bacterial sialidases in virulence, and indicates that their inhibition with chemotherapeutics could be a promising strategy for periodontitis therapy.
牙周炎发病和进展的关键是口腔细菌与宿主之间的复杂关系。与严重牙周炎最相关的生物体是牙周病原菌的红色复合体： 、 和 。这些生物体表达唾液酸酶，可从宿主糖蛋白上切割唾液酸，并通过多种机制促进疾病的发生。在这里，我们表达并纯化了重组 唾液酸酶 SiaPG（PG_0352），并对其在一系列底物（包括宿主唾液糖蛋白）上的活性进行了表征，同时强调了不能切割二乙酰化的唾液酸-这一现象被来自 的 NanS 唾液酸酯酶克服。事实上，SiaPG 需要 NanS 来最大限度地从高度 O-乙酰化的底物（如牛唾液粘蛋白）中提取唾液酸，这暗示了这些口腔微生物群成员从宿主来源释放唾液酸时可能存在种间合作。商业上可获得的化疗药物扎那米韦抑制了 SiaPG 和 的活性，表明其作为毒力抑制剂的潜力，它还抑制了粘蛋白中唾液酸的释放，并能够抑制 在口腔糖蛋白源上形成生物膜。扎那米韦还抑制了 和其他牙周病原菌对口腔上皮细胞的附着和侵袭，无论是在单种感染还是在混合感染实验中，这表明抑制混合微生物群落中宿主-病原体相互作用的潜力。这项研究拓宽了我们对细菌唾液酸酶在毒力中的多种作用的理解，并表明用化疗药物抑制它们可能是治疗牙周炎的一种有前途的策略。
