title: Neutrophils and neutrophil serine proteases are increased in the spleens of estrogen-treated C57BL/6 mice and several strains of spontaneous lupus-prone mice.
abstract: Estrogen, a natural immunomodulator, regulates the development and function of diverse immune cell types. There is now renewed attention on neutrophils and neutrophil serine proteases (NSPs) such as neutrophil elastase (NE), proteinase 3 (PR3), and cathepsin G (CG) in inflammation and autoimmunity. In this study, we found that although estrogen treatment significantly reduced total splenocytes number, it markedly increased the splenic neutrophil absolute numbers in estrogen-treated C57BL/6 (B6) mice when compared to placebo controls. Concomitantly, the levels of NSPs and myeloperoxidase (MPO) were highly upregulated in the splenocytes from estrogen-treated mice. Despite the critical role of NSPs in the regulation of non-infectious inflammation, by employing NE-/-/PR3-/-/CG-/- triple knock out mice, we demonstrated that the absence of NSPs affected neither estrogen's ability to increase splenic neutrophils nor the induction of inflammatory mediators (IFNγ, IL-1β, IL-6, TNFα, MCP-1, and NO) from ex vivo activated splenocytes. Depletion of neutrophils in vitro in splenocytes with anti-Ly6G antibody also had no obvious effect on NSP expression or LPS-induced IFNγ and MCP-1. These data suggest that estrogen augments NSPs, which appears to be independent of enhancing ex vivo inflammatory responses. Since estrogen has been implicated in regulating several experimental autoimmune diseases, we extended our observations in estrogen-treated B6 mice to spontaneous autoimmune-prone female MRL-lpr, B6-lpr and NZB/WF1 mice. There was a remarkable commonality with regards to the increase of neutrophils and concomitant increase of NSPs and MPO in the splenic cells of different strains of autoimmune-prone mice and estrogen-treated B6 mice. Collectively, since NSPs and neutrophils are involved in diverse pro-inflammatory activities, these data suggest a potential pathologic implication of increased neutrophils and NSPs that merits further investigation.
authors.affiliation: Infectious Disease Research Facility (IDRF), Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine (VMCVM), Virginia Tech, Blacksburg, Virginia, United States of America.
authors.forename: Rujuan
authors.initials: R
authors.lastname: Dai
authors.affiliation: Infectious Disease Research Facility (IDRF), Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine (VMCVM), Virginia Tech, Blacksburg, Virginia, United States of America.
authors.forename: Catharine
authors.initials: C
authors.lastname: Cowan
authors.affiliation: Infectious Disease Research Facility (IDRF), Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine (VMCVM), Virginia Tech, Blacksburg, Virginia, United States of America.
authors.forename: Bettina
authors.initials: B
authors.lastname: Heid
authors.affiliation: Infectious Disease Research Facility (IDRF), Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine (VMCVM), Virginia Tech, Blacksburg, Virginia, United States of America.
authors.forename: Deena
authors.initials: D
authors.lastname: Khan
authors.affiliation: Infectious Disease Research Facility (IDRF), Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine (VMCVM), Virginia Tech, Blacksburg, Virginia, United States of America.
authors.forename: Zhihong
authors.initials: Z
authors.lastname: Liang
authors.affiliation: Department of Medicine, Division of Rheumatology, Washington University School of Medicine, St. Louis, Missouri, United States of America.
authors.forename: Christine T N
authors.initials: CT
authors.lastname: Pham
authors.affiliation: Infectious Disease Research Facility (IDRF), Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine (VMCVM), Virginia Tech, Blacksburg, Virginia, United States of America.
authors.forename: S Ansar
authors.initials: SA
authors.lastname: Ahmed
mesh_terms: D000818:Animals; D015153:Blotting, Western; D056649:Cathepsin G / Q000235:genetics / Q000378:metabolism; D002478:Cells, Cultured; D016207:Cytokines / Q000378:metabolism; D004967:Estrogens / Q000008:administration & dosage / Q000494:pharmacology*; D005260:Female; D005434:Flow Cytometry; D015870:Gene Expression / Q000187:drug effects; D018836:Inflammation Mediators / Q000378:metabolism; D019272:Leukocyte Elastase / Q000235:genetics / Q000378:metabolism; D008297:Male; D008810:Mice, Inbred C57BL; D019463:Mice, Inbred MRL lpr; D008814:Mice, Inbred NZB; D018345:Mice, Knockout; D053146:Myeloblastin / Q000235:genetics / Q000378:metabolism; D009504:Neutrophils / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism; D009195:Peroxidase / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D057057:Serine Proteases / Q000235:genetics / Q000378:metabolism*; D013045:Species Specificity; D013154:Spleen / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism
chemical_list: D016207:Cytokines; D004967:Estrogens; D018836:Inflammation Mediators; D009195:Peroxidase; D057057:Serine Proteases; D056649:Cathepsin G; D019272:Leukocyte Elastase; D053146:Myeloblastin