PDF(Pubmed)
Abstract：
Cryptosporidium causes severe gastrointestinal disease resulting from the ingestion of oocysts, followed by oocyst excystation in the small intestine and the release of infective sporozoites. An understudied strategy for Cryptosporidium inactivation is purposeful oocyst excystation, as sporozoites do not survive long in the environment. This study showed that C. parvum oocyst excystation was induced by direct contact with various glycosaminoglycans (GAGs), including heparin (Hep), chondroitin sulfate A (CSA), and hyaluronan (HA), assembled on polydopamine (PD)-functionalized surfaces. PD surfaces elicited 97.9 ± 3.6% oocyst attachment, with some of the attached oocysts partially (7.3 ± 1.3%) or fully (4.0 ± 0.6%) excysted after 4 days. The PD-GAG surfaces (GAG concentration = 2 mg/mL) elicited similarly high attachment (>97%) and higher oocyst excystation efficiencies after 4 days. The PD-Hep surfaces elicited the highest number of attached excysted oocysts (11.8 ± 0.63% partially excysted; 11.9 ± 0.49% fully excysted), and the PD-HA surfaces elicited the lowest (8.8 ± 2.1% partially excysted; 7.8 ± 1.2% fully excysted). Surface characterization revealed that the addition of GAGs to the PD surface changed both the surface roughness as well as the surface wettability. Treatment of oocysts with an enzyme that degraded the surface glycocalyx markedly reduced excystation (to <2%) of the oocysts attached to the PD and PD-GAG surfaces. These findings suggest that GAGs provide an important local signal for the excystation of C. parvum oocysts and that certain surface-expressed oocyst receptors are necessary for efficient excystation. These oocyst-receptor relationships may be useful in the design of functionalized surfaces for the purposeful inactivation of oocysts in the environment or in water treatment systems. IMPORTANCE Polydopamine surfaces functionalized with glycosaminoglycans were shown to facilitate the attachment and excystation of Cryptosporidium parvum oocysts. Our findings suggest that a surface-expressed receptor on the oocyst wall plays a key role in excystation, with glycosaminoglycans serving as ligands that trigger the initiation of the process. Future technologies and treatment strategies designed to promote premature excystation of oocysts will minimize the ingestion of sporozoites that initiate infection. Therefore, the results from this study have important implications for the protection of public health from waterborne cryptosporidiosis and may serve as a foundation for engineered surfaces designed to remove oocysts from surface waters or inactivate oocysts in water treatment systems.
摘要：
隐孢子虫由于摄入卵囊而导致严重的胃肠道疾病，其次是小肠的卵囊脱落和感染性子孢子的释放。隐孢子虫灭活的一项研究策略是有目的的卵囊切除，因为子孢子在环境中不能存活很长时间。这项研究表明，小梭菌卵囊脱落是通过与各种糖胺聚糖（GAGs）直接接触而引起的，包括肝素（Hep），硫酸软骨素A（CSA），和透明质酸（HA），组装在聚多巴胺（PD）功能化的表面。PD表面引起97.9±3.6%卵囊附着，4天后，一些附着的卵囊部分（7.3±1.3％）或完全（4.0±0.6％）排出。PD-GAG表面(GAG浓度=2mg/mL)在4天后引起类似的高附着(>97%)和更高的卵囊排出效率。PD-Hep表面引起最多数量的附着卵囊（11.8±0.63％部分排出；11.9±0.49％完全排出），PD-HA表面引起的最低（部分排出8.8±2.1％；完全排出7.8±1.2％）。表面表征表明，在PD表面添加GAG会改变表面粗糙度和表面润湿性。用降解表面糖萼的酶处理卵囊显著减少了附着于PD和PD-GAG表面的卵囊的脱落(至<2%)。这些发现表明，GAG为小梭菌卵囊的脱落提供了重要的局部信号，并且某些表面表达的卵囊受体对于有效的脱落是必需的。这些卵囊-受体关系可用于设计功能化表面,用于环境或水处理系统中的卵囊的有目的的失活。重要性显示用糖胺聚糖官能化的聚多巴胺表面有助于隐孢子虫卵囊的附着和脱落。我们的研究结果表明，卵囊壁上的表面表达受体在卵囊脱落中起着关键作用。以糖胺聚糖作为引发该过程的配体。旨在促进卵囊过早脱落的未来技术和治疗策略将最大程度地减少引发感染的子孢子的摄入。因此,这项研究的结果对保护公众健康免受水性隐孢子虫病的影响具有重要意义，并且可以作为工程表面的基础，该工程表面旨在从地表水中去除卵囊或在水处理系统中灭活卵囊。
