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Principal Investigator: Koichi Yuki
Organization: BOSTON CHILDREN'S HOSPITAL
Fiscal Year: 2024
Award: $386,433
Funding agency: National Institute of General Medical Sciences
Project Summary/ Abstract
Sepsis remains to be associated with a high mortality of 20 to 30% with annual cost of $24 billion, accounting
for nearly one-fifth of the total aggregate costs in all the hospitalizations in the United States. Current sepsis
management is supportive. Therefore, identifying therapeutic approaches is an urgent task to improve the
outcome of sepsis. Neutrophils eradicate microbes as the first-line defense innate immune cells. In sepsis,
exaggerated de novo neutrophil production called emergency granulopoiesis occurs mainly via G-CSF
production. However, immature neutrophils are also released into a circulation to meet a high demand for
neutrophil number, but they have less antimicrobial defense functions, leading to worse host defense in septic
patients. G-CSF itself does not trigger full neutrophil maturation. Thus, an intervention to attain the
enhancement of neutrophil maturation is critical in sepsis for better host defense. Integrin CD11c was
considered a sensitive marker to differentiate sepsis from systemic inflammatory response syndrome. We
previously showed that CD11c KO mice had worse survival in the polymicrobial sepsis induced by cecal
ligation and puncture (CLP) surgery, indicating the critical role of CD11c in sepsis. There has been a paucity of
research about its functional role in vivo. We unexpectedly identified that CD11c was expressed in the bone
marrow (BM) neutrophils (largely intracellular) and its deficiency was associated with less BM neutrophil
maturation. In a mouse model to recapitulate emergency granulopoiesis, mature neutrophils were released in
significantly less quantity in CD11c KO mice compared to wild type (WT) mice, further suggesting its
importance in neutrophil maturation. We created CD11c constitutively active knock-in (KI) mice, which
demonstrated to have more mature neutrophils in the BM in a steady-state condition and during infection with
better bacterial eradication and outcomes. In addition, our in vitro neutrophil maturation experiments using
primary murine CD11c KO neutrophils or HL-60 cells devoid of CD11c by CRISPR/Cas9 technology showed
less neutrophil maturation. Based on these results, we hypothesized that CD11c activity would significantly
regulate the degree of neutrophil maturation in a steady state and emergency granulopoiesis in a cell-intrinsic
manner. Our preliminary data suggested that CD11c would also regulate a subset of neutrophil effector
functions irrelevant of maturation. Thus, we will determine the role of CD11c in neutrophil maturation and
effector functions in a steady state and sepsis in Aim 1 and Aim 2. Because IQGAP1 was suggested to be a
binding partner for CD11c, its role will also be studied to delineate the mechanism of how CD11c regulates
neutrophil maturation and effector functions. Studies will be done by using human sepsis subjects and murine
models. Because there are no CD11c small molecule agonists and antagonists available, we will screen them
in Aim 3. Upon the completion of the proposal, we expect that we would solidify that CD11c would be a critical
regulator of neutrophil maturation and effector functions for a therapeutic intervention in sepsis.
Terms: <0-11 years old><21+ years old><Accounting><Adhesion Molecule><Adult><Adult Human><Advocate><Aging><Agonist><Assay><Binding><Bioassay><Biological Assay><Biological Markers><Blood><Blood Neutrophil><Blood Polymorphonuclear Neutrophil><Blood Precursor Cell><Blood Reticuloendothelial System><Blood leukocyte><Bone Marrow><Bone Marrow Reticuloendothelial System><CD11c><CD18><CD34><CD34 gene><CLP model><CLP mouse model><CRISPR approach><CRISPR based approach><CRISPR method><CRISPR methodology><CRISPR technique><CRISPR technology><CRISPR tools><CRISPR-CAS-9><CRISPR-based method><CRISPR-based technique><CRISPR-based technology><CRISPR-based tool><CRISPR/CAS approach><CRISPR/Cas method><CRISPR/Cas technology><CRISPR/Cas9><CRISPR/Cas9 technology><Cas nuclease technology><Cecal ligation perforation><Cell Adhesion Molecule Gene><Cell Adhesion Molecules><Cell Body><Cell surface><Cells><Child><Child Youth><Children (0-21)><Circulation><Clinical Trials><Clustered Regularly Interspaced Short Palindromic Repeats approach><Clustered Regularly Interspaced Short Palindromic Repeats method><Clustered Regularly Interspaced Short Palindromic Repeats methodology><Clustered Regularly Interspaced Short Palindromic Repeats technique><Clustered Regularly Interspaced Short Palindromic Repeats technology><Colony Stimulating Factor 3><Complement Receptor><Data><Dendritic Cells><Development><E coli><E. coli><Emergencies><Emergency Situation><Escherichia coli><Future><Gene Transcription><Generations><Genes><Genetic Transcription><Goals><Granulocyte Colony-Stimulating Factor><Granulopoiesis><HL-60 Cells><HL60 Cells><HPCA1><Hematopoietic Progenitor Cells><Hematopoietic stem cells><Heterogeneity><Hospital Admission><Hospital Mortality><Hospitalization><Host Defense><Human><ITGAX><ITGAX gene><ITGB2><ITGB2 gene><Immune><Immunes><In Vitro><In-house Mortalities><Incidence><Infection><Inhospital Mortality><Integrin Binding><Integrins><Integrins Extracellular Matrix><Intervention><Intervention Strategies><KI mice><KO mice><Knock-in Mouse><Knock-out Mice><Knockout Mice><LCAMB><Leukocytes><Leukocytes Reticuloendothelial System><Ligand Binding><Ligands><MF17><Marrow Neutrophil><Marrow leukocyte><Mice><Mice Mammals><Microbe><Modeling><Modern Man><Molecular Interaction><Morbidity><Morbidity - disease rate><Murine><Mus><Neutrophilic Granulocyte><Neutrophilic Leukocyte><Null Mouse><Ontology><Operative Procedures><Operative Surgical Procedures><Outcome><Output><Patients><Phagocytes><Phagocytic Cell><Play><Pluripoietin><Polymorphonuclear Cell><Polymorphonuclear Leukocytes><Polymorphonuclear Neutrophils><Population><Production><Proliferating><RNA Expression><Reporting><Research><Role><Sampling><Sepsis><Signal Pathway><Sterility><Supportive Therapy><Supportive care><Surgical><Surgical Interventions><Surgical Procedure><Systemic Inflammatory Response Syndrome><Testing><Therapeutic><Therapeutic Intervention><Time><Transcription><Translations><United States><Veiled Cells><White Blood Cells><White Cell><Wild Type Mouse><adulthood><aged><amebocyte><antagonism><antagonist><anti-microbial><antimicrobial><bio-markers><biologic marker><biomarker><blood cell progenitor><blood infection><blood progenitor><blood stem cell><blood-forming stem cell><bloodstream infection><candidate identification><cecal ligation and perforation><cecal ligation and puncture><cecal ligation puncture><cecum ligation and puncture><cecum ligation puncture><cell adhesion protein><cost><cytokine><developmental><experiment><experimental research><experimental study><experiments><granulocyte colony stimulating factor><hematopoietic progenitor><hematopoietic stem progenitor cell><hemopoietic progenitor><hemopoietic stem cell><improved><improved outcome><in vivo><integrin bound><intervention therapy><interventional strategy><kids><knockin mice><member><microbial><mortality><mouse model><murine model><neutrophil><new drug treatments><new drugs><new pharmacological therapeutic><new therapeutics><new therapy><next generation therapeutics><novel><novel drug treatments><novel drugs><novel pharmaco-therapeutic><novel pharmacological therapeutic><novel therapeutics><novel therapy><peripheral blood><polymicrobial sepsis><precursor cell><scRNA-seq><sepsis patients><septic><septic patients><single cell RNA-seq><single cell RNAseq><single cell expression profiling><single cell transcriptomic profiling><single-cell RNA sequencing><small molecule><social role><sterile><surgery><transcriptome profiling><transcriptomic profiling><translation><white blood cell><white blood corpuscle><wildtype mouse><youngster>