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: 10266039
• 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/10266039
• 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; 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; risk stratification; 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.

艰难梭菌是美国领先的医院感染，对VA急性和长期关注 定期护理设施。艰难梭菌感染（CDI）靶向艰难梭菌细菌的当前疗法。 但这可能导致共生细菌杀死，从而降低对艰难梭菌的抗性性，而艰难梭菌的抗性 反过来可以促进复发性CDI。这是急需CDI治疗的少量群保留方法。 宿主嗜中性粒细胞的大小是CDI后疾病结局的关键调节剂。我们以前报道了 瘦素 - leptin受体（LEPR）轴在确定CDI诱导的嗜中性粒细胞中的关键作用：我们的研究表明， LEPR（Q223R）中的SNP（最多50％的人）调节了两只小鼠的中性粒细胞数 和患有CDI的患者。突变体LEPR等位基因（RR基因型）的纯合性与增加有关 中性粒细胞计数以及急性CDI期间显着的组织损伤和更高的死亡率，但更早 组织中性粒细胞和临床疾病的分辨率。由于有助于的异质性嗜中性粒细胞种群 对于组织损伤和组织，对于控制疾病预后至关重要，我们假设不同 中性粒细胞类型会响应艰难梭菌，并有助于组织损伤和修复。 现在，我们拥有引人注目的初步数据，该数据揭示了骨髓和 艰难梭菌感染小鼠的结肠组织。我们已经根据细胞内颗粒定义了这些种群 （侧面散射在FACS上）和2整联蛋白（CD11b）表达。在RR小鼠中，组织数量增加 CDI急性期相关的中性粒细胞（总体和活化的种群，sschicd11bhi细胞） 强烈患有严重的组织损伤和临床疾病。随后，组织中性粒细胞的下降（均为总体） 激活的种群）与较严重的肠道病理学相关，并从临床中恢复早期恢复 这些小鼠的疾病。此外，共生肠道微生物群在不同的生成中起重要作用 中性粒细胞种群及其从小鼠的骨髓室动员。 我们的核心假设是，LEPR Q变化与肠道微生物组的改变有关 以STAT3依赖性方式影响中性粒细胞对艰难梭菌组织反应的影响。我们现在 在CDI和 了解LEPR SNP和肠道微生物群与SNP调节形成相关的机制 CDI后不同的嗜中性粒细胞。 我们将回答以下主要问题： 1）在急性和分辨率期间形成的中性粒细胞的功能和表型特征是什么 QQ和RR基因型的患者和小鼠的CDI阶段？ 2）这些中性粒细胞如何诱导结肠组织损伤并调节CDI发病机理？ 3）特定肠道细菌在确定这种中性粒细胞种群的发展中有什么作用？ 4）在CDI后，LEPR下游的信号通路是什么？ 我们研究的目的是确定在课程中促进中性粒细胞亚群的致病性和解决方案 CDI并了解其发展的机制。识别组织破坏和 CDI之后的修复性嗜中性粒细胞类型有可能识别设计新的微生物群的目标 未来的CDI疗法。另外，了解常见人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LEPR SNP的精确医学方法 用于CDI患者风险分层的新型遗传生物标志物。