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.

艰难梭菌是美国主要的医院感染，也是 VA 急性和长期感染的主要关注点。 目前针对艰难梭菌感染 (CDI) 的治疗方法是使用抗生素来治疗艰难梭菌。 但这可能导致共生细菌被杀死，从而降低对艰难梭菌的定植抵抗力，而艰难梭菌 反过来又会促进 CDI 复发，因此迫切需要 CDI 治疗的微生物群保护方法。 宿主中性粒细胞增多的程度是 CDI 后疾病结果的关键调节因素。 瘦素-瘦素受体 (LEPR) 轴在调节 CDI 诱导的中性粒细胞增多中发挥关键作用：我们的研究表明 LEPR 中的 SNP (Q223R) 存在于高达 50% 的人类中，可调节两只小鼠的中性粒细胞数量 突变 LEPR 等位基因（RR 基因型）的纯合性与 CDI 患者的增加有关。 急性 CDI 期间，中性粒细胞计数伴随着显着的组织损伤和更高的死亡率，但更早 由于异质性中性粒细胞群体有助于解决组织中性粒细胞增多症和临床疾病。 组织损伤和组织对于调节传染病结果至关重要，我们假设不同的 中性粒细胞类型响应艰难梭菌而发展，并有助于组织损伤和修复。 我们现在拥有令人信服的初步数据，揭示了骨髓中不同的中性粒细胞群 我们根据细胞内颗粒定义了艰难梭菌感染小鼠的结肠组织。 （FACS 上的侧向散射）和 2 整合素 (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（总数以及激活的细胞群、SSChiCD11bhi 细胞） 严重伴有严重的组织损伤和临床疾病，随后组织中性粒细胞（总数）下降。 和激活的人群）与较不严重的肠道病理和较早从临床症状中恢复相关 此外，共生肠道微生物群在不同疾病的产生中发挥着重要作用。 中性粒细胞群及其从小鼠骨髓室中的动员。 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， 我们现在以 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。 提议全面定义 CDI 过程中中性粒细胞群的演变， 了解 LEPR SNP 和与 SNP 相关的肠道微生物群调节形成的机制 CDI 后明显的中性粒细胞。 我们将回答以下主要问题： 1) 急性期和消退期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发病机制？ 3) 特定肠道细菌在调节中性粒细胞群发育中的作用是什么？ 4) CDI 后调节中性粒细胞异质性的 LEPR 信号下游通路有哪些？ 我们研究的目标是在过程中识别致病性和促进中性粒细胞亚群的解决 CDI 并了解其发展机制、组织损伤和识别。 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 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 LEPR SNP 所在的精准医学方法 用作 CDI 患者风险分层的新型遗传生物标志物。