Role of a common leptin receptor polymorphism in regulating neutrophil heterogeneity after C. difficile infection

常见瘦素受体多态性在艰难梭菌感染后调节中性粒细胞异质性中的作用

• 批准号: 9974287
• 负责人: Rajat Madan
• 金额: --
• 依托单位: CINCINNATI VA MEDICAL CENTER RESEARCH
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-07-01 至 2023-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9974287
• 关键词: Acute; Admission activity; Adoptive Transfer; Alleles; Antibiotic Therapy; Antibiotics; Bacteria; Bacterial Infections; Binding; Biological Assay; Bone Marrow; Bone Marrow Cells; CCAAT-Enhancer-Binding Proteins; Cecum; Cell Line; Cell surface; Cells; Characteristics; Clinical; Clostridium difficile; Coculture Techniques; Communicable Diseases; Cytoplasmic Granules; Data; Development; Diphtheria Toxin; Disease; Disease Outcome; Enzyme-Linked Immunosorbent Assay; Evolution; Flow Cytometry; Future; Generations; Genetic Markers; Genetic Polymorphism; Genotype; Goals; Granulopoiesis; Health care facility; Healthcare Systems; Heterogeneity; High Prevalence; Human; Human Genetics; ITGAM gene; In Vitro; Infection; Inflammation; Inflammatory; Integrins; Interleukin-8B Receptor; Intestines; Knowledge; Leptin; Leukocytosis; Long-Term Care; Measures; Medical center; Morbidity - disease rate; Mus; Mutation; Nature; Neutropenia; Neutrophilia; Nosocomial Infections; Outcome; Pathogenesis; Pathogenicity; Pathology; Pathway interactions; Patients; Phase; Phenotype; Physiological; Play; Population; Public Health; Receptor Signaling; Recovery; Recurrence; Reporting; Reproduction spores; Resolution; Risk; Risk Factors; Risk stratification; Role; Severities; Side; Signal Pathway; Signal Transduction; Single Nucleotide Polymorphism; Stat3 protein; Stomach; Tissues; base; c-myc Genes; colonization resistance; commensal bacteria; cost estimate; design; genetic variant; gut bacteria; gut microbiome; gut microbiota; human disease; improved; in vivo; intestinal epithelium; intestinal injury; leptin receptor; metagenomic sequencing; microbiota; migration; mortality; mouse model; mutant; neutrophil; novel; peripheral blood; population based; precision medicine; receptor; repaired; response; targeted treatment; tissue repair; transcription factor

Clostridium difficile is the leading nosocomial infection in the U.S and a major concern for VA acute and long- term care facilities. The current therapies for C. difficile infection (CDI) target C. difficile bacterium with antibiotics. But this can leads to killing of commensal bacteria and thus reduce colonization resistance to C. difficile which can in turn promote recurrent CDI. Thus, microbiota sparing approaches for CDI therapy are urgently needed. Magnitude of host neutrophilia is a key regulator of disease outcomes after CDI. We have previously reported a key role for leptin-leptin receptor (LEPR) axis in regulating CDI-induced neutrophilia: our studies revealed that a SNP in LEPR (Q223R), which is present in up to 50% of humans, regulates neutrophil numbers in both mice and patients with CDI. Homozygosity for the mutant LEPR allele (RR genotype) was associated with increased neutrophil counts along with significant tissue damage and higher mortality during acute CDI, but earlier resolution of tissue neutrophilia and clinical disease. Since heterogenous neutrophil populations that contribute to both tissue damage and tissue are critical in regulating infectious disease outcomes, we postulate that different neutrophil types develop in response to C. difficile and contribute to tissue damage and repair. We now have compelling preliminary data that reveals distinct neutrophil populations in bone marrow and colonic tissue of C. difficile infected mice. We have defined these populations based on intra-cellular granules (side scatter on FACS) and 2 integrin (CD11b) expression. In RR mice, an increase in the number of tissue neutrophils (total as well as the activated population, SSChiCD11bhi cells) during acute phase of CDI correlated strongly with severe tissue damage and clinical disease. Subsequently, decline in tissue neutrophils (both total and activated population) was associated with less severe intestinal pathology and earlier recovery from clinical disease in these mice. Further, commensal gut microbiota play an important role in the generation of different neutrophil populations and their mobilization from bone marrow compartment of mice. Our central hypothesis is that LEPR Q to R change is associated with alterations in the gut microbiome that influence the effect of neutrophils on tissue responses to C. difficile in a STAT3-dependent manner. We now propose to comprehensively define the evolution of neutrophil populations during the course of CDI and understand the mechanisms by which LEPR SNP and gut microbiota associated with the SNP regulate formation of distinct neutrophils after CDI. We will answer the following main questions: 1) What are the functional and phenotypic characteristics of neutrophils formed during acute and resolution phase of CDI in both patients and mice with the QQ and RR genotype? 2) How do these neutrophils induce colonic tissue damage and regulate CDI pathogenesis? 3) What is the role of specific gut bacteria in regulating the development of such neutrophil populations? 4) What are the signaling pathways downstream of LEPR that regulate neutrophil heterogeneity after CDI? The goal of our studies is to identify pathogenic and resolution promoting neutrophil subsets during the course of CDI and understand the mechanisms of their development. Identification of the tissue damaging and reparative neutrophil types after CDI has the potential to identify new microbiota-sparing targets for the design of future CDI therapies. In addition, understanding the role of a common human genetic variant in regulating neutrophil heterogeneity and CDI outcomes can be used in precision medicine approaches where LEPR SNP is utilized as a novel genetic biomarker for risk stratification of CDI patients.

艰难梭菌是美国主要的医院感染，也是VA急性和长期的主要问题。 长期护理设施。目前治疗C.艰难梭菌感染（CDI）靶向C.艰难梭菌与抗生素 但这会导致肠道细菌的死亡，从而降低对C.困难的是， 可以反过来促进CDI的复发。因此，迫切需要用于CDI治疗的微生物群保护方法。 宿主嗜中性粒细胞数量是CDI后疾病结局的关键调节因子。之前我们已经报道 瘦素-瘦素受体（LEPR）轴在调节CDI诱导的嗜中性粒细胞中的关键作用：我们的研究表明， LEPR中的SNP（Q223 R）存在于高达50%的人类中，调节两只小鼠的中性粒细胞数量 CDI患者。突变型LEPR等位基因（RR基因型）的纯合性与增加 中性粒细胞计数沿着有显著的组织损伤和较高的死亡率，但在急性CDI期间， 解决组织嗜中性粒细胞和临床疾病。由于异质性中性粒细胞群 对组织损伤和组织的影响在调节传染病结果中至关重要，我们假设不同的 嗜中性粒细胞类型响应于C.并有助于组织损伤和修复。 我们现在有了令人信服的初步数据，揭示了骨髓中不同的中性粒细胞群， 结肠组织C.艰难梭菌感染的小鼠。我们已经根据细胞内颗粒定义了这些群体 (side FACS上的散射）和CD11b 2整联蛋白（CD11b）表达。在RR小鼠中，组织数量的增加 CDI急性期的中性粒细胞（总细胞和活化细胞群，SSChiCD11bhi细胞）与CDI相关， 严重的组织损伤和临床疾病。随后，组织中性粒细胞（总 和激活的人群）与较轻的肠道病理和较早的临床恢复有关。 这些老鼠的疾病此外，消化道微生物群在不同微生物的产生中起重要作用。 嗜中性粒细胞群体及其从小鼠骨髓区室的动员。 我们的中心假设是，LEPR Q到R的变化与肠道微生物组的改变有关， 影响中性粒细胞对组织对C.以STAT3依赖的方式表达艰难梭菌。我们现在 建议全面定义CDI过程中中性粒细胞群体的演变， 了解LEPR SNP和与SNP相关的肠道微生物群调节形成的机制 CDI后中性粒细胞明显增多 我们将回答以下主要问题： 1)急性期和缓解期形成的中性粒细胞的功能和表型特征是什么 在QQ和RR基因型的患者和小鼠的CDI期？ 2)这些中性粒细胞如何诱导结肠组织损伤并调节CDI发病机制？ 3)特定的肠道细菌在调节这些中性粒细胞群体的发育中起什么作用？ 4)CDI后LEPR下游调节中性粒细胞异质性的信号通路是什么？ 本研究的目的是确定病程中致病和促进消退的中性粒细胞亚群 并了解其发展机制。组织损伤的识别和 CDI后的修复性中性粒细胞类型有可能为设计确定新的微生物群保护目标 未来的CDI疗法此外，了解常见的人类遗传变异在调节中的作用 中性粒细胞异质性和CDI结果可用于精确医学方法，其中LEPR SNP是 用作CDI患者风险分层的新型遗传生物标志物。