Protein Sialylation and De-Sialyation in Cell Surface Glycoprotein Homeostasis and Disease

细胞表面糖蛋白稳态和疾病中的蛋白质唾液酸化和去唾液酸化

基本信息

批准号：
10211776
负责人：
JAMEY MARTH
金额：
$ 48.75万
依托单位：
SANFORD BURNHAM PREBYS MEDICAL DISCOVERY INSTITUTE
依托单位国家：
美国
项目类别：
财政年份：
2021
资助国家：
美国
起止时间：
2021-02-01 至 2026-01-31
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10211776
关键词：
Age Aging Alkaline Phosphatase Anti-Inflammatory Agents Bacterial Infections Blood Body Weight decreased Cell surface Clinical Trials Colitis Colon Data Development Diarrhea Disease Disease model Dose Drug Metabolic Detoxication Engineering Enteral Enterocytes Environmental Risk Factor Enzymes Epithelial Epithelial Cells Family Food Poisoning Frequencies Functional disorder Funding Genetic Glycoproteins Gram-Negative Bacterial Infections Half-Life Histopathology Homeostasis Human Immune response Infection Inflammation Inflammatory Inflammatory Bowel Diseases Intestinal Diseases Intestines Isoenzymes Knockout Mice Laboratories Link Lipopolysaccharides Maintenance Measurement Measures Membrane Glycoproteins Modeling Molecular Mucin-2 Staining Method Mucins Mus Neuraminidase Pathogenesis Pathogenicity Peptide Hydrolases Play Post-Translational Protein Processing Predisposition Prevention Protein Dephosphorylation Proteins Proteolysis Publications Publishing Rectal Prolapse Recurrence Regulation Reporting Research Resistance Role Salmonella Salmonella enterica Salmonella typhimurium Sepsis Serotyping Sialic Acids Sialyltransferases Stomach TLR4 gene Testing Time Tissues Ulcerative Colitis Yang cell type cohort colon bacteria commensal bacteria comparative cytokine enteric pathogen foodborne illness gastrointestinal inflammatory disease of the intestine inorganic phosphate member mouse model novel pathogen pathogenic bacteria premature recurrent infection response sialylation

项目摘要

SUMMARY Protein sialylation is a post-translational modification produced by members of a family of sialyltransferases. We recently discovered that the resulting sialic acid linkages are involved in the regulation of glycoprotein abundance and function in an intrinsic homeostatic mechanism that is targeted by multiple pathogens. Environmental factors are dominant in the origins of the human Inflammatory Bowel Diseases (IBDs) and seasonal bacterial infections have been implicated. We therefore developed a mouse model of repeated human food poisoning comprised of recurrent low-titer non-lethal gastric infections of the Gram-negative bacterial pathogen Salmonella enterica Typhimurium (ST), a leading cause of human foodborne illness worldwide. In this unique model, the ST pathogen was rapidly cleared by the host, however a progressively severe and persistent colitis developed similar to Ulcerative Colitis (UC). We demonstrated that pathogenesis was linked to the disabling of a protective mechanism in the host involving the anti-inflammatory Intestinal Alkaline Phosphatase (IAP) glycoprotein enzyme produced by enterocytes. Recurrent ST infections resulted in Toll-like receptor-4 (Tlr4) induction of neuraminidase (Neu) activity and host Neu3 abundance with nascent IAP de-sialylation and endocytic degradation, thereby reducing IAP half-life, abundance, and function. IAP deficiency was similarly acquired in mice lacking the ST3Gal6 sialyltransferase resulting in spontaneous colitis. The disease mechanism in both cases was Tlr4-dependent and linked to reduced dephosphorylation and detoxification of the lipopolysaccharide-phosphate produced by commensal bacteria of the colon. In humans, similar modulation of IAP and Neu3 have been reported in colitis, and genetic deficiency of IAP causes colitis, supporting the rationale for ongoing clinical trials of IAP augmentation and neuraminidase inhibition. However, the key involvement of Neu3 remains to be established. Research proposed herein will directly test the role of host Neu3 in the onset and progression of colitis among Neu3-null mice. In addition, the possibility that other enteric Gram-negative pathogens similarly provoke IAP deficiency will be investigated with the development of other recurrent non-lethal gastric infection models using related Gram-negative enteric pathogens including the hypervirulent Salmonella enterica Choleraesuis serovar. We have recently measured elevated Neu activity and Neu3 protein abundance in the colon during recurrent ST infection associated with the de-sialylation of Mucin– 2 (Muc2), the major glycoprotein component of the protective mucin barrier. The mechanism of erosion of the mucin barrier in colitis remains unknown but plays a large role in pathogenesis. We have recently linked erosion of the mucin barrier to reductions of Muc2 protein sialylation, likely by ST3Gal6. Remarkably, Neu treatment increases Muc2 proteolysis with reduced Muc2 abundance. Research proposed herein will determine the role of Muc2 sialylation by ST3Gal6 in generating and maintaining the protective mucin barrier. Together these studies will provide important advances pertaining to the prevention and treatment of colitis.

概括蛋白质唾液酸化是由唾液酸转移酶家族成员产生的翻译后修饰。我们最近发现由此产生的唾液酸键参与糖蛋白的调节多种病原体针对的内在稳态机制中的丰度和功能。环境因素在人类炎症性肠病 (IBD) 的起源中起主导作用因此，我们开发了一种反复感染的小鼠模型。人类食物中毒，由革兰氏阴性菌反复发生的低滴度非致命性胃部感染组成细菌病原体肠沙门氏菌鼠伤寒 (ST)，人类食源性疾病的主要原因在这个独特的模型中，ST 病原体迅速被宿主清除，但清除过程是逐渐进行的。严重和持续性结肠炎的发展与溃疡性结肠炎（UC）相似。与宿主体内涉及抗炎肠道的保护机制的失效有关肠细胞产生的碱性磷酸酶 (IAP) 糖蛋白导致反复 ST 感染。 Toll 样受体 4 (Tlr4) 诱导神经氨酸酶 (Neu) 活性和宿主 Neu3 丰度与新生 IAP 去唾液酸化和内吞降解，从而降低 IAP 半衰期、丰度和功能。缺乏 ST3Gal6 唾液酸转移酶的小鼠也出现了类似的缺陷，导致自发性结肠炎。两种情况下的疾病机制均依赖于 Tlr4，并与去磷酸化减少和人类结肠共生细菌产生的脂多糖磷酸盐的解毒。 IAP 和 Neu3 的类似调节在结肠炎中已有报道，并且 IAP 的遗传缺陷会导致结肠炎，支持正在进行的 IAP 增强和神经氨酸酶抑制临床试验的基本原理。 Neu3 的关键参与仍有待确定，本文提出的研究将直接测试其作用。宿主Neu3在Neu3缺失小鼠结肠炎的发病和进展中的作用此外，还有其他可能性。肠道革兰氏阴性病原体同样会引起 IAP 缺乏症，随着使用相关革兰氏阴性肠道病原体的其他复发性非致命性胃感染模型，包括我们最近检测到高毒力沙门氏菌猪霍乱血清型的 Neu 活性升高。复发性 ST 感染期间结肠中 Neu3 蛋白丰度与粘蛋白去唾液酸化相关 2 (Muc2)，保护性粘蛋白屏障的主要糖蛋白成分侵蚀机制。结肠炎中的粘蛋白屏障仍然未知，但在发病机制中发挥着重要作用。粘蛋白屏障的侵蚀导致 Muc2 蛋白唾液酸化的减少，可能是 ST3Gal6 引起的。本文提出的研究将增加 Muc2 蛋白水解作用并降低 Muc2 丰度。确定 ST3Gal6 对 Muc2 唾液酸化在生成和维持保护性粘蛋白屏障中的作用。这些研究将共同为结肠炎的预防和治疗提供重要进展。